View source for Lithium-ion battery

{{Short description|Type of rechargeable battery}}
{{Redirect|Lithium-ion|the metal element|Lithium}}
{{Redirect-distinguish|Liion|Lion}}
{{Use dmy dates|date=October 2019}}
{{Infobox battery
| image   = File:Li ion laptop battery.jpg
| caption = A lithium-ion battery pack from a [[Laptop|laptop computer]]
| EtoW    = {{cvt|1|–|270|W.h/kg|kJ/kg}}<ref name="mw"/>
| EtoS    = {{cvt|250|–|693|W.h/L|J/cm3}}<ref>{{cite web  | url = https://www.orbtronic.com/content/NCR18650B-Datasheet-Panasonic-Specifications.pdf  | title = NCR18650B |publisher=Panasonic |access-date=7 October 2016 |archive-url=https://web.archive.org/web/20180817085228/https://na.industrial.panasonic.com/sites/default/pidsa/files/ncr18650b.pdf |archive-date=17 August 2018 }}</ref><ref>{{cite web  | url = https://cdn.shopify.com/s/files/1/0674/3651/files/panasonic-ncr18650-ga-spec-sheet.pdf  | title = NCR18650GA  | access-date = 2 July 2017  | archive-date = 8 March 2021  | archive-url = https://web.archive.org/web/20210308084905/https://cdn.shopify.com/s/files/1/0674/3651/files/panasonic-ncr18650-ga-spec-sheet.pdf  | url-status = live  }}</ref>
| PtoW={{nowrap|1–10,000 W/kg}}<ref name="mw"/>
|CtoDE=80–90%<ref name="Valøen-2007">{{cite conference |last1=Valøen |first1=Lars Ole |last2=Shoesmith |first2=Mark I. |url=http://www.pluginhighway.ca/PHEV2007/proceedings/PluginHwy_PHEV2007_PaperReviewed_Valoen.pdf |title=The effect of PHEV and HEV duty cycles on battery and battery pack performance |conference=Proceedings of the Plug-in Highway Electric Vehicle Conference |date=1–2 November 2007|archive-url=https://web.archive.org/web/20090326150713/http://www.pluginhighway.ca/PHEV2007/proceedings/PluginHwy_PHEV2007_PaperReviewed_Valoen.pdf |archive-date=26 March 2009 }}</ref>
| EtoCP=8.7 Wh/US$ (US$115/kWh)<ref name="Bloomberg-2021">{{cite web | url = https://about.bnef.com/blog/lithium-ion-battery-pack-prices-see-largest-drop-since-2017-falling-to-115-per-kilowatt-hour-bloombergnef/ | title = 
Lithium-Ion Battery Pack Prices See Largest Drop Since 2017, Falling to $115 per Kilowatt-Hour: BloombergNEF
| date = 10 December 2024 | access-date = 13 December 2024 | publisher = Bloomberg New Energy Finance}}</ref>
| SDR=0.35% to 2.5% per month depending on state of charge<ref name="Redondo-Iglesias-2016"/><!--when full. Near zero when partial-->
| CD={{nowrap|400–1,200 [[Battery cycle|cycles]]}}
<ref>{{cite web |url=http://www.thermoanalytics.com/support/publications/batterytypesdoc.html |title=Battery Types and Characteristics for HEV |date=2007 |website=ThermoAnalytics |archive-url=https://web.archive.org/web/20150520021436/http://www.thermoanalytics.com/support/publications/batterytypesdoc.html |archive-date=20 May 2015 |url-status=dead |access-date=11 June 2010}}</ref>
| NomV={{nowrap|3.6 / 3.7 / 3.8 / 3.85 [[Volts|V]],}} {{nowrap|{{chem|Li|Fe|PO|4}} {{val|3.2|ul=V}},}} {{nowrap|{{chem|Li|4|Ti|5|O|12}} {{val|2.3|ul=V}}}}
}}

A '''lithium-ion''' or '''Li-ion battery''' is a type of [[rechargeable battery]] that uses the reversible [[Intercalation (chemistry)|intercalation]] of Li<sup>+</sup> ions into electronically [[Electrical conductor|conducting]] solids to store energy. Li-ion batteries are characterized by higher [[specific energy]], [[energy density]], and [[Energy efficiency (physics)|energy efficiency]] and a longer [[cycle life]] and calendar life than other types of rechargeable batteries. Also noteworthy is a dramatic improvement in lithium-ion battery properties after their market introduction in 1991; over the following 30 years, their volumetric energy density increased threefold while their cost dropped tenfold.<ref>{{Cite journal |last1=Chagas |first1=Luciana Gomes |last2=Jeong |first2=Sangsik |last3=Hasa |first3=Ivana |last4=Passerini |first4=Stefano |date=2019-06-26 |title=Ionic Liquid-Based Electrolytes for Sodium-Ion Batteries: Tuning Properties To Enhance the Electrochemical Performance of Manganese-Based Layered Oxide Cathode |url=https://pubs.acs.org/doi/10.1021/acsami.9b03813 |journal=ACS Applied Materials & Interfaces |language=en |volume=11 |issue=25 |pages=22278–22289 |doi=10.1021/acsami.9b03813 |pmid=31144802 |issn=1944-8244}}</ref> In late 2024 global demand passed {{val|1|u=[[Kilowatt-hour|terawatt-hour]]}} per year,<ref>{{cite web |last1=Maisch |first1=Marija |title=Annual lithium-ion demand surpasses 1 TWh for the first time |url=https://www.ess-news.com/2024/12/20/annual-lithium-ion-demand-surpasses-1-twh-for-the-first-time/ |website=Energy Storage |date=20 December 2024}}</ref> while production capacity was more than twice that.<ref>{{cite web |last1=Rayner |first1=Tristan |title=The battery boom of 2024 as one of five trends in renewables |url=https://www.ess-news.com/2025/01/02/the-battery-boom-of-2024-as-one-of-five-trends-in-renewables/ |website=Energy Storage |date=2 January 2025}}</ref>

The invention and commercialization of Li-ion batteries [[Timeline of historic inventions|has had a large impact on technology]],<ref>The lithium-ion battery: State of the art and future perspectives. 2018. Renew Sust Energ Rev. 89/292-308. G. Zubi, R. Dufo-Lopez, M. Carvalho, G. Pasaoglu. doi: 10.1016/j.rser.2018.03.002.</ref> as recognized by the 2019 [[Nobel Prize in Chemistry]].
Li-ion batteries have enabled portable [[consumer electronics]], [[laptop computers]], [[cellular phones]], and [[electric cars]]. Li-ion batteries also see significant use for [[Battery storage power station|grid-scale energy storage]] as well as  military and aerospace applications.

[[M. Stanley Whittingham]] conceived intercalation electrodes in the 1970s and created the first rechargeable lithium-ion battery, based on a [[titanium disulfide]] cathode and a lithium-aluminium anode, although it suffered from safety problems and was never commercialized.<ref name="TRFSUNY-2017">{{cite web |title=Binghamton professor recognized for energy research |url=https://www.rfsuny.org/rf-news/binghamton-energy/binghamton---energy.html |website=The Research Foundation for the State University of New York |access-date=10 October 2019 |archive-date=30 October 2017 |archive-url=https://web.archive.org/web/20171030175258/https://www.rfsuny.org/rf-news/binghamton-energy/binghamton---energy.html |url-status=live }}</ref> [[John Goodenough]] expanded on this work in 1980 by using [[lithium cobalt oxide]] as a cathode.<ref name="NobelPrize-2019">{{cite web |title=The Nobel Prize in Chemistry 2019 |url=https://www.nobelprize.org/prizes/chemistry/2019/summary/ |website=[[Nobel Prize]] |publisher=[[Nobel Foundation]] |year=2019 |access-date=1 January 2020 |archive-date=21 May 2020 |archive-url=https://web.archive.org/web/20200521195355/https://www.nobelprize.org/prizes/chemistry/2019/summary/ |url-status=live }}</ref> The first prototype of the modern Li-ion battery, which uses a carbonaceous anode rather than lithium metal, was developed by [[Akira Yoshino]] in 1985 and commercialized by a [[Sony]] and [[Asahi Kasei]] team led by Yoshio Nishi in 1991.<ref name="NAE">{{cite web  | title = Yoshio Nishi  | url = https://www.nae.edu/105800/Yoshio-Nishi  | website = [[National Academy of Engineering]]  | access-date = 12 October 2019  | archive-date = 11 April 2019  | archive-url = https://web.archive.org/web/20190411130013/https://www.nae.edu/105800/Yoshio-Nishi  | url-status = live  }}</ref> Whittingham, Goodenough, and Yoshino were awarded the 2019 Nobel Prize in Chemistry for their contributions to the development of lithium-ion batteries.

Lithium-ion batteries can be a fire or explosion hazard as they contain flammable electrolytes. Progress has been made in the development and manufacturing of safer lithium-ion batteries.<ref>{{cite journal | doi=10.1016/j.jechem.2020.10.017 | title=A review of lithium-ion battery safety concerns: The issues, strategies, and testing standards | year=2021 | last1=Chen | first1=Yuqing | last2=Kang | first2=Yuqiong | last3=Zhao | first3=Yun | last4=Wang | first4=Li | last5=Liu | first5=Jilei | last6=Li | first6=Yanxi | last7=Liang | first7=Zheng | last8=He | first8=Xiangming | last9=Li | first9=Xing | last10=Tavajohi | first10=Naser | last11=Li | first11=Baohua | journal=Journal of Energy Chemistry | volume=59 | pages=83–99 | s2cid=228845089 | doi-access=free | bibcode=2021JEnCh..59...83C }}</ref> Lithium-ion [[Solid-state battery|solid-state batteries]] are being developed to eliminate the flammable electrolyte.<ref>{{Cite web |date=2022-12-07 |title=Flameproofing lithium-ion batteries with salt |url=https://www6.slac.stanford.edu/news/2022-12-07-flameproofing-lithium-ion-batteries-salt |access-date=2025-05-28 |website=SLAC National Accelerator Laboratory |quote=A new class of polymer-based electrolytes that are nonflammable even at high temperatures is being developed to improve lithium-ion battery safety.}}</ref> [[Battery recycling|Recycled batteries]] can create toxic waste, including from toxic metals, and are a fire risk.{{Cn|date=June 2025}} Both [[lithium]] and other minerals can have significant issues in mining, with lithium being water intensive in often arid regions and other minerals used in some Li-ion chemistries potentially being [[Conflict resource|conflict minerals]] such as [[cobalt]].<ref>{{Cite web |last=Gross |first=Daniel A. |date=2021-01-07 |title=The Lithium Gold Rush: Inside the Race to Power Electric Vehicles |url=https://e360.yale.edu/features/lithium-mining-water-andes-argentina |access-date=2025-05-28 |website=Yale Environment 360 |quote=Lithium extraction is extremely water intensive and is taking place in some of the driest places on Earth, threatening fragile ecosystems and Indigenous livelihoods.}}</ref> [[Environmental impacts of lithium-ion batteries|Environmental issues]] have encouraged some researchers to improve mineral efficiency and find alternatives such as [[lithium iron phosphate]] lithium-ion chemistries or non-lithium-based battery chemistries such as [[Sodium-ion battery|sodium-ion]] and [[Iron-air battery|iron-air]] batteries.

"Li-ion battery" can be considered a generic term involving at least 12 different chemistries; see [[List of battery types]]. Lithium-ion cells can be manufactured to optimize energy density or power density.<ref>{{Cite journal|last1=Lain|first1=Michael J.|last2=Brandon |first2=James|last3=Kendrick|first3=Emma |date=December 2019|title=Design Strategies for High Power vs. High Energy Lithium Ion Cells|journal=Batteries|language=en|volume=5|issue=4|page=64 |doi=10.3390/batteries5040064|quote=Commercial lithium ion cells are now optimized for either high energy density or high power density. There is a trade-off in cell design between power and energy requirements.|doi-access=free}}</ref> Handheld electronics mostly use [[Lithium polymer battery|lithium polymer batteries]] (with a polymer gel as an electrolyte), a lithium cobalt oxide ({{chem|LiCoO|2}}) cathode material, and a [[graphite]] anode, which together offer high energy density.<ref>{{cite journal |last1=Mauger |first1=A |last2=Julien |first2=C.M. |date=28 June 2017 |title=Critical review on lithium-ion batteries: are they safe? Sustainable? |journal=Ionics |volume=23 |issue=8 |pages=1933–1947 |doi=10.1007/s11581-017-2177-8 |s2cid=103350576 |url=https://hal.sorbonne-universite.fr/hal-01558209/file/Mauger_2017_Critical_review_on.pdf |access-date=26 July 2019 |archive-date=2 March 2023 |archive-url=https://web.archive.org/web/20230302135828/https://hal.sorbonne-universite.fr/hal-01558209/file/Mauger_2017_Critical_review_on.pdf |url-status=live }}</ref><ref name="Ellis-2020" /> [[Lithium iron phosphate]] ({{chem|LiFePO|4}}),<ref>{{Cite web |date=2025-03-26 |title=Lithium iron phosphate |url=https://www.ogniwa-lifepo4.pl/blog/akumulator-litowo-zelazowo-fosforanowy.html |access-date=2025-05-28}}</ref> [[lithium ion manganese oxide battery|lithium manganese oxide]] ({{chem|LiMn|2|O|4}} [[spinel]], or {{chem|Li|2|MnO|3}}-based lithium-rich layered materials, LMR-NMC), and [[lithium nickel manganese cobalt oxide]] ({{chem|LiNiMnCoO|2}} or NMC) may offer longer life and a higher discharge rate. NMC and its derivatives are widely used in the [[electrification of transport]], one of the main technologies (combined with [[renewable energy]]) for reducing [[greenhouse gas emissions]] from vehicles.<ref>{{Cite journal |last1=Zhang |first1=Runsen |last2=Fujimori |first2=Shinichiro |date=2020-02-19 |title=The role of transport electrification in global climate change mitigation scenarios |journal=Environmental Research Letters |language=en |volume=15 |issue=3 |page=034019 |doi=10.1088/1748-9326/ab6658 |bibcode=2020ERL....15c4019Z |s2cid=212866886 |issn=1748-9326|doi-access=free |hdl=2433/245921 |hdl-access=free }}</ref>

== History ==
{{Main|History of the lithium-ion battery}}

Research on rechargeable Li-ion batteries dates to the 1960s; one of the earliest examples is a {{Chem|Cu|F|2}}/Li battery developed by [[NASA]] in 1965. The breakthrough that produced the earliest form of the modern Li-ion battery was made by British chemist [[M. Stanley Whittingham]] in 1974, who first used [[titanium disulfide]] ({{Chem|Ti|S|2}}) as a cathode material, which has a layered structure that can [[Intercalation (chemistry)|take in lithium ions]] without significant changes to its [[crystal structure]]. [[Exxon]] tried to commercialize this battery in the late 1970s, but found the synthesis expensive and complex, as {{Chem|Ti|S|2}} is sensitive to moisture and releases toxic [[hydrogen sulfide|hydrogen sulfide ({{Chem|H|2|S}})]] gas on contact with water. More prohibitively, the batteries were also prone to spontaneously catch fire due to the presence of metallic lithium in the cells. For this, and other reasons, Exxon discontinued the development of Whittingham's lithium-titanium disulfide battery.<ref name="Li-2018a" />

In 1980, working in separate groups Ned A. Godshall et al.,<ref>{{cite journal | doi = 10.1016/0025-5408(80)90135-X | title = Thermodynamic investigations of ternary lithium-transition metal-oxygen cathode materials|journal=Materials Research Bulletin| volume=15|issue=5| page=561|year=1980|last1= Godshall|first1=N.A.|last2= Raistrick|first2=I.D.|last3=Huggins|first3=R.A.}}</ref><ref>Godshall, Ned A. (17 October 1979) "Electrochemical and Thermodynamic Investigation of Ternary Lithium-Transition Metal-Oxide Cathode Materials for Lithium Batteries: Li<sub>2</sub>MnO<sub>4</sub> [[spinel]], LiCoO<sub>2</sub>, and LiFeO<sub>2</sub>", Presentation at 156th Meeting of the Electrochemical Society, Los Angeles, CA.</ref><ref>Godshall, Ned A. (18 May 1980) ''Electrochemical and Thermodynamic Investigation of Ternary Lithium-Transition Metal-Oxygen Cathode Materials for Lithium Batteries''. Ph.D. Dissertation, Stanford University</ref> and, shortly thereafter, [[Koichi Mizushima (scientist)|Koichi Mizushima]] and [[John B. Goodenough]], after testing a range of alternative materials, replaced {{Chem|Ti|S|2}} with [[lithium cobalt oxide]] ({{Chem|Li|Co|O|2}}, or LCO), which has a similar layered structure but offers a higher voltage and is much more stable in air. This material would later be used in the first commercial Li-ion battery, although it did not, on its own, resolve the persistent issue of flammability.<ref name="Li-2018a">{{Cite journal|last1=Li|first1=Matthew |last2=Lu|first2=Jun |last3=Chen|first3=Zhongwei |last4=Amine|first4=Khalil |date=2018-06-14|title=30 Years of Lithium-Ion Batteries|journal=Advanced Materials |language=en|volume=30|issue=33|page=1800561 |doi=10.1002/adma.201800561|pmid=29904941|bibcode=2018AdM....3000561L |osti=1468617 |s2cid=205286653|issn=0935-9648|doi-access=free}}</ref>

These early attempts to develop rechargeable Li-ion batteries used lithium metal anodes, which were ultimately abandoned due to safety concerns, as lithium metal is unstable and prone to [[Dendrite (crystal)|dendrite]] formation, which can cause [[Short circuit|short-circuiting]]. The eventual solution was to use an intercalation anode, similar to that used for the cathode, which prevents the formation of lithium metal during battery charging. The first to demonstrate lithium ion reversible intercalation into graphite anodes was [[Jürgen Otto Besenhard]] in 1974.<ref name="Besenhard-1974">{{Cite journal |last1=Besenhard |first1=J. O. |last2=Fritz |first2=H. P. |date=1974-06-25 |title=Cathodic reduction of graphite in organic solutions of alkali and NR4+ salts |url=https://linkinghub.elsevier.com/retrieve/pii/S0022072874801464 |journal=Journal of Electroanalytical Chemistry and Interfacial Electrochemistry |volume=53 |issue=2 |pages=329–333 |doi=10.1016/S0022-0728(74)80146-4 |issn=0022-0728}}</ref><ref name="Li-2018b">{{Cite journal |last1=Li |first1=Matthew |last2=Lu |first2=Jun |last3=Chen |first3=Zhongwei |last4=Amine |first4=Khalil |date=2018-06-14 |title=30 Years of Lithium-Ion Batteries |journal=Advanced Materials |language=en |volume=30 |issue=33 |page=1800561 |bibcode=2018AdM....3000561L |doi=10.1002/adma.201800561 |issn=0935-9648 |osti=1468617 |pmid=29904941 |s2cid=205286653 |doi-access=free}}</ref> Besenhard used organic solvents such as carbonates, however these solvents decomposed rapidly providing short battery cycle life. Later, in 1980, [[Rachid Yazami]] used a solid organic electrolyte, [[polyethylene oxide]], which was more stable.<ref>International Meeting on Lithium Batteries, Rome, 27–29 April 1982, C.L.U.P. Ed. Milan, Abstract #23</ref><ref>{{Cite journal |last1=Yazami |first1=R. |last2=Touzain |first2=P. |year=1983 |title=A reversible graphite-lithium negative electrode for electrochemical generators |journal=Journal of Power Sources |volume=9 |issue=3 |pages=365–371 |bibcode=1983JPS.....9..365Y |doi=10.1016/0378-7753(83)87040-2}}</ref>

In 1985, [[Akira Yoshino]] at [[Asahi Kasei]] Corporation discovered that [[petroleum coke]], a less graphitized form of carbon, can reversibly intercalate Li-ions at a low potential of ~0.5 V relative to Li+ /Li without structural degradation.<ref>Yoshino, A., Sanechika, K. & Nakajima, T. Secondary battery. JP patent 1989293 (1985)</ref> Its structural stability originates from its [[amorphous carbon]] regions, which serving as covalent joints to pin the layers together. Although it has a lower capacity compared to graphite (~Li0.5C6, 186&nbsp;mAh g–1), it became the first commercial intercalation anode for Li-ion batteries owing to its cycling stability. In 1987, Yoshino patented what would become the first commercial lithium-ion battery using this anode. He used Goodenough's previously reported [[LiCoO2|LiCoO<sub>2</sub>]] as the cathode and a [[carbonate ester]]-based electrolyte. The battery was assembled in the discharged state, which made it safer and cheaper to manufacture. In 1991, using Yoshino's design, [[Sony]] began producing and selling the world's first rechargeable lithium-ion batteries. The following year, a [[joint venture]] between [[Toshiba]] and Asahi Kasei Co. also released a lithium-ion battery.<ref name="Li-2018a" />

Significant improvements in energy density were achieved in the 1990s by replacing Yoshino's soft carbon anode first with [[hard carbon]] and later with graphite. In 1990, [[Jeff Dahn]] and two colleagues at [[Dalhousie University]] (Canada) reported reversible intercalation of lithium ions into graphite in the presence of [[ethylene carbonate]] solvent (which is solid at room temperature and is mixed with other solvents to make a liquid). This represented the final innovation of the era that created the basic design of the modern lithium-ion battery.<ref>{{Cite journal | last1 = Fong | first1 = R. | last2 = von Sacken | first2 = U. | last3 = Dahn | first3 = Jeff | title = Studies of lithium intercalation into carbons using nonaqueous electrochemical cells. | journal = J. Electrochem. Soc.| volume = 137 | pages = 2009–2013 | year = 1990 | issue = 7 | doi = 10.1149/1.2086855 | bibcode = 1990JElS..137.2009F }}</ref>

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In 2010, global lithium-ion battery production capacity was 20 gigawatt-hours.<ref>{{cite web |title=Lithium-ion batteries for mobility and stationary storage applications |publisher=[[European Commission]] |url=https://setis.ec.europa.eu/document/download/9c5d115b-2b45-4378-b454-06affaf9a44c_en |archive-url= https://web.archive.org/web/20190714021601/https://ec.europa.eu/jrc/sites/jrcsh/files/jrc114616_li-ion_batteries_two-pager_final.pdf |archive-date=14 July 2019 |quote=global lithium-ion battery production from about 20GWh (~6.5bn€) in 2010 |url-status=live}}</ref> By 2016, it was 28 GWh, with 16.4 GWh in China.<ref>{{cite web |url=https://www.greentechmedia.com/articles/read/switching-from-lithium-ion-could-be-harder-than-you-think |title=Switching From Lithium-Ion Could Be Harder Than You Think |date=19 October 2017 |access-date=20 October 2017 |archive-date=19 October 2017 |archive-url=https://web.archive.org/web/20171019202000/https://www.greentechmedia.com/articles/read/switching-from-lithium-ion-could-be-harder-than-you-think |url-status=live }}</ref> Global production capacity was 767 GWh in 2020, with China accounting for 75%.<ref>{{cite news |last1=Murray |first1=Cameron |title=Europe and US will shave c.10% off China's Li-ion production capacity market share by 2030 |url=https://www.energy-storage.news/europe-and-us-will-shave-c-10-off-chinas-li-ion-production-capacity-market-share-by-2030/ |website=Energy Storage News |date=8 March 2022 |access-date=8 March 2022 |archive-date=8 March 2022 |archive-url=https://web.archive.org/web/20220308214949/https://www.energy-storage.news/europe-and-us-will-shave-c-10-off-chinas-li-ion-production-capacity-market-share-by-2030/ |url-status=live }}</ref> Production in 2021 is estimated by various sources to be between 200 and 600 GWh, and predictions for 2023 range from 400 to 1,100 GWh.<ref>{{cite report |title=National Blueprint for Lithium Batteries |date=October 2020 |publisher=U.S. Department of Energy |page=12 |url=https://www.energy.gov/sites/default/files/2021-06/FCAB%20National%20Blueprint%20Lithium%20Batteries%200621_0.pdf |access-date=1 August 2021 |archive-date=28 July 2021 |archive-url=https://web.archive.org/web/20210728161024/https://www.energy.gov/sites/default/files/2021-06/FCAB%20National%20Blueprint%20Lithium%20Batteries%200621_0.pdf |url-status=live }}</ref>

In 2012, John B. Goodenough, [[Rachid Yazami]] and [[Akira Yoshino]] received the 2012 IEEE Medal for Environmental and Safety Technologies for developing the lithium-ion battery; Goodenough, Whittingham, and Yoshino were awarded the 2019 [[Nobel Prize in Chemistry]] "for the development of lithium-ion batteries".<ref>{{cite web| title = The Nobel Prize in Chemistry 2019| publisher = Nobel Foundation| url = https://www.nobelprize.org/prizes/chemistry/2019/press-release/| access-date = 4 June 2023| archive-date = 8 December 2019| archive-url = https://web.archive.org/web/20191208071439/https://www.nobelprize.org/prizes/chemistry/2019/press-release/| url-status = live}}</ref> [[Jeff Dahn]] received the ECS Battery Division Technology Award (2011) and the Yeager award from the International Battery Materials Association (2016).

In April 2023, [[CATL]] announced that it would begin scaled-up production of its semi-solid condensed matter battery that produces a then record 500 [[Wh/kg]]. They use electrodes made from a gelled material, requiring fewer binding agents. This in turn shortens the manufacturing cycle. One potential application is in battery-powered airplanes.<ref name="Hanley-2023">{{cite news |last1=Hanley |first1=Steve |title=Condensed Matter Battery From CATL Targets Electric Airplanes |url=https://cleantechnica.com/2023/04/21/condensed-matter-battery-from-catl-targets-electric-airplanes/ |publisher=CleanTechnica |date=21 April 2023 |access-date=30 April 2023 |archive-date=30 April 2023 |archive-url=https://web.archive.org/web/20230430144004/https://cleantechnica.com/2023/04/21/condensed-matter-battery-from-catl-targets-electric-airplanes/ |url-status=live }}</ref><ref name="China-2023">{{cite news |title=China's CATL unveils condensed matter battery to power civil aircraft |url=https://www.reuters.com/technology/chinas-catl-unveils-condensed-matter-battery-power-civil-aircraft-2023-04-19/ |publisher=Reuters |date=19 April 2023 |access-date=30 April 2023 |archive-date=30 April 2023 |archive-url=https://web.archive.org/web/20230430143954/https://www.reuters.com/technology/chinas-catl-unveils-condensed-matter-battery-power-civil-aircraft-2023-04-19/ |url-status=live }}</ref><ref name="Warwick-2023">{{cite news |last1=Warwick |first1=Graham |title=China's CATL Targets Energy-Dense Battery At Electric Aircraft |url=https://aviationweek.com/aerospace/emerging-technologies/chinas-catl-targets-energy-dense-battery-electric-aircraft |agency=Aviation Week |publisher=Informa Markets |date=19 April 2023 |access-date=30 April 2023 |archive-date=30 April 2023 |archive-url=https://web.archive.org/web/20230430143954/https://aviationweek.com/aerospace/emerging-technologies/chinas-catl-targets-energy-dense-battery-electric-aircraft |url-status=live }}</ref> Another new development of lithium-ion batteries are [[flow batteries]] with redox-targeted solids, that use no binders or electron-conducting additives, and allow for completely independent scaling of energy and power.<ref>Flow batteries with solid energy boosters. 2022. J Electrochem Sci Eng. 12/4, 731–66. Y.V. Tolmachev, S.V. Starodubceva. doi: 10.5599/jese.1363.</ref>

== Design ==
[[File:Lithium-Ion Cell cylindric.JPG|thumb|Cylindrical Panasonic [[18650 battery|18650]] lithium-ion cell before closing.]]
[[File:Lithium Ionen Akku Überwachungselektronik.jpg|thumb|Lithium-ion battery monitoring electronics (over-charge and deep-discharge protection)]]
[[File:Liion-18650-AA-battery.jpg|thumb|upright|Left: AA alkaline battery. Right: 18650 lithium ion battery]]

Generally, the negative electrode of a conventional lithium-ion cell is made from [[graphite]]. The positive electrode is typically a metal [[oxide]] or phosphate. The [[electrolyte]] is a [[lithium]] [[Salt (chemistry)|salt]] in an [[organic compound|organic]] [[solvent]].<ref name="Silberberg-2006">Silberberg, M. (2006). ''Chemistry: The Molecular Nature of Matter and Change'', 4th Ed. New York (NY): McGraw-Hill Education. p. 935, {{ISBN|0-07-721650-4}}.</ref> The negative electrode (which is the [[anode]] when the cell is discharging) and the positive electrode (which is the [[cathode]] when discharging) are prevented from shorting by a separator.<ref name="Li-2021">{{Cite journal |last1=Li |first1=Ao |last2=Yuen |first2=Anthony Chun Yin |last3=Wang |first3=Wei |last4=De Cachinho Cordeiro |first4=Ivan Miguel |last5=Wang |first5=Cheng |last6=Chen |first6=Timothy Bo Yuan |last7=Zhang |first7=Jin |last8=Chan |first8=Qing Nian |last9=Yeoh |first9=Guan Heng |date=January 2021 |title=A Review on Lithium-Ion Battery Separators towards Enhanced Safety Performances and Modelling Approaches |journal=Molecules |language=en |volume=26 |issue=2 |page=478 |doi=10.3390/molecules26020478 |issn=1420-3049 |pmc=7831081 |pmid=33477513 |doi-access=free}}</ref> The electrodes are connected to the powered circuit through two pieces of metal called current collectors.<ref name="Zhu-2020" />

The negative and positive electrodes swap their electrochemical roles (anode and [[cathode]]) when the cell is charged. Despite this, in discussions of battery design the negative electrode of a rechargeable cell is often just called "the anode" and the positive electrode "the cathode".

In its fully lithiated state of LiC<sub>6</sub>, graphite correlates to a theoretical capacity of 1339 [[coulomb]]s per gram (372 mAh/g).<ref name="Shao-2020">[https://pubs.acs.org/doi/full/10.1021/acsami.0c12376 G. Shao et al.: Polymer-Derived SiOC Integrated with a Graphene Aerogel As a Highly Stable Li-Ion Battery Anode] ACS Appl. Mater. Interfaces 2020, 12, 41, 46045–46056</ref> The positive electrode is generally one of three materials: a layered [[oxide]] (such as [[lithium cobalt oxide]]), a [[Polyelectrolyte|polyanion]] (such as [[lithium iron phosphate]]) or a [[spinel]] (such as lithium [[manganese oxide]]).<ref>{{Cite journal |last1=Thackeray |first1=M. M. |last2=Thomas |first2=J. O. |last3=Whittingham |first3=M. S. |doi=10.1557/mrs2000.17 |title=Science and Applications of Mixed Conductors for Lithium Batteries |journal=MRS Bulletin |volume=25 |issue=3 |pages=39–46 |year=2011|s2cid=98644365 }}</ref> More experimental materials include [[graphene]]-containing electrodes, although these remain far from commercially viable due to their high cost.<ref>{{cite journal |last1=El-Kady |first1=Maher F. |last2=Shao |first2=Yuanlong |last3=Kaner |first3=Richard B. |title=Graphene for batteries, supercapacitors and beyond |journal=Nature Reviews Materials |date=July 2016 |volume=1 |issue=7 |page=16033 |doi=10.1038/natrevmats.2016.33|bibcode=2016NatRM...116033E }}</ref>

Lithium reacts vigorously with water to form [[lithium hydroxide]] (LiOH) and [[hydrogen]] gas. Thus, a non-aqueous electrolyte is typically used, and a sealed container rigidly excludes moisture from the battery pack. The non-aqueous electrolyte is typically a mixture of organic carbonates such as [[ethylene carbonate]] and [[propylene carbonate]] containing [[Coordination complex|complexes]] of lithium ions.<ref>[http://www.tek.com/Measurement/Service/msds/01914600.pdf MSDS: National Power Corp Lithium Ion Batteries] {{Webarchive | url = https://web.archive.org/web/20110626215943/http://www.tek.com/Measurement/Service/msds/01914600.pdf  | date = 26 June 2011 }} (PDF). tek.com; Tektronix Inc., 7 May 2004. Retrieved 11 June 2010.</ref> [[Ethylene carbonate]] is essential for making solid electrolyte interphase on the carbon anode,<ref>Revisiting the Ethylene Carbonate-Propylene Carbonate Mystery with Operando Characterization. 2022. Adv Mater Interfaces. 9/8, 7. T. Melin, R. Lundstrom, E.J. Berg. doi: 10.1002/admi.202101258.</ref> but since it is solid at room temperature, a liquid [[solvent]] (such as [[propylene carbonate]] or [[diethyl carbonate]]) is added.

The electrolyte salt is almost always{{citation needed|date=April 2024}}<!-- unsupported by this old 2004 source --> [[lithium hexafluorophosphate]] ({{chem|LiPF|6}}), which combines good [[Conductivity (electrolytic)|ionic conductivity]] with chemical and electrochemical stability. The [[hexafluorophosphate]] [[Ion#Anions and cations|anion]] is essential for [[Passivation (chemistry)|passivating]] the aluminium current collector used for the positive electrode. A titanium tab is ultrasonically [[welded]] to the aluminium current collector.
Other salts like [[lithium perchlorate]] ({{chem|LiClO|4}}), [[lithium tetrafluoroborate]] ({{chem|LiBF|4}}), and [[lithium bis(trifluoromethanesulfonyl)imide]] ({{chem|LiC|2|F|6|NO|4|S|2}}) are frequently used in research in tab-less [[Button cell|coin cells]], but are not usable in larger format cells,<ref>{{cite journal |last1=Xu |first1=Kang |title=Nonaqueous Liquid Electrolytes for Lithium-Based Rechargeable Batteries |journal=Chemical Reviews |date=1 October 2004 |volume=104 |issue=10 |pages=4303–4418 |doi=10.1021/cr030203g|pmid=15669157 }}</ref> often because they are not compatible with the aluminium current collector. Copper (with a [[Spot welding|spot-welded]] [[nickel]] tab) is used as the current collector at the negative electrode.

Current collector design and surface treatments may take various forms: foil, mesh, foam (dealloyed), etched (wholly or selectively), and coated (with various materials) to improve electrical characteristics.<ref name="Zhu-2020">{{Cite web|url=https://www.researchgate.net/publication/346987573|title=A review of current collectors for lithium-ion batteries}}</ref>

Depending on materials choices, the [[voltage]], [[energy density]], life, and safety of a lithium-ion cell can change dramatically. Current effort has been exploring the use of [[Nanoarchitectures for lithium-ion batteries|novel architectures]] using [[nanotechnology]] to improve performance. Areas of interest include nano-scale electrode materials and alternative electrode structures.<ref>{{Cite journal |last1=Joyce |first1=C. |last2=Trahy |first2=L. |last3=Bauer |first3=S.| last4=Dogan |first4=F. |last5=Vaughey |first5=J. |doi=10.1149/2.107206jes |title=Metallic Copper Binders for Lithium-Ion Battery Silicon Electrodes| journal=Journal of the Electrochemical Society| volume=159 |issue=6 |pages=909–914| year=2012|doi-access=free }}</ref>

=== Electrochemistry ===

The reactants in the electrochemical reactions in a lithium-ion cell are the materials of the electrodes, both of which are compounds containing lithium atoms. Although many thousands of different materials have been investigated for use in lithium-ion batteries, only a very small number are commercially usable. All commercial Li-ion cells use intercalation compounds as active materials.<ref>{{cite web |title=Anode vs Cathode: What's the difference? |url=https://www.biologic.net/topics/anode-cathode-positive-and-negative-battery-basics/ |access-date=25 May 2023 |publisher=BioLogic |archive-date=25 May 2023 |archive-url=https://web.archive.org/web/20230525123331/https://www.biologic.net/topics/anode-cathode-positive-and-negative-battery-basics/ |url-status=live }}</ref> The negative electrode is usually graphite, although [[Lithium–silicon battery|silicon]] is often mixed in to increase the capacity. The electrolyte is usually [[lithium hexafluorophosphate]], dissolved in a mixture of [[Carbonate ester|organic carbonates]]. A number of different materials are used for the positive electrode, such as [[LiCoO2|LiCoO<sub>2</sub>]], [[LiFePO4|LiFePO<sub>4</sub>]], and [[lithium nickel manganese cobalt oxides]].

During cell discharge the negative electrode is the anode and the positive electrode the cathode: electrons flow from the anode to the cathode through the external circuit. An oxidation [[half-reaction]] at the anode produces positively charged lithium ions and negatively charged electrons. The oxidation half-reaction may also produce uncharged material that remains at the anode. Lithium ions move through the electrolyte; electrons move through the external circuit toward the cathode where they recombine with the cathode material in a reduction half-reaction. The electrolyte provides a conductive medium for lithium ions but does not partake in the electrochemical reaction. The reactions during discharge lower the chemical potential of the cell, so discharging transfers [[energy]] from the cell to wherever the electric current dissipates its energy, mostly in the external circuit.

During charging these reactions and transports go in the opposite direction: electrons move from the positive electrode to the negative electrode through the external circuit. To charge the cell the external circuit has to provide electrical energy. This energy is then stored as chemical energy in the cell (with some loss, e. g., due to [[coulombic efficiency]] lower than 1).

Both electrodes allow lithium ions to move in and out of their structures with a process called ''insertion'' (''intercalation'') or ''extraction'' (''deintercalation''), respectively.

As the lithium ions "rock" back and forth between the two electrodes, these batteries are also known as "rocking-chair batteries" or "swing batteries" (a term given by some European industries).<ref>{{Cite journal |last1=Guyomard |first1=Dominique |last2=Tarascon |first2=Jean-Marie |date=1994 |title=Rocking-chair or lithium-ion rechargeable lithium batteries |journal=Advanced Materials|volume=6 |issue=5 |pages=408–412 |doi=10.1002/adma.19940060516 |bibcode=1994AdM.....6..408G |issn=1521-4095}}</ref><ref>{{Cite journal |title=Lithium-ion rechargeable batteries |journal=Journal of Power Sources |volume=51 |issue=1–2 |last1=Megahed |first1=Sid |last2=Scrosati |first2=Bruno |pages=79–104 |doi=10.1016/0378-7753(94)01956-8 |year=1994 |bibcode=1994JPS....51...79M}}</ref>

The following equations exemplify the chemistry (left to right: discharging, right to left: charging).

The negative electrode half-reaction for the graphite is<ref name="Bergveld-2002">{{cite book |last1=Bergveld |first1=H. J. |last2=Kruijt |first2=W. S. |last3=Notten |first3=P. H. L. |year=2002  | title = Battery Management Systems: Design by Modelling |publisher=[[Springer Science+Business Media|Springer]] |pages=107–108, 113|isbn=978-94-017-0843-2}}</ref><ref name="Dhameja-2001">{{cite book |last=Dhameja |first=S |year=2001  | title = Electric Vehicle Battery Systems |publisher=[[Newnes Press]] |page=12 |isbn=978-075-06991-67}}</ref>
: <chem>LiC6 <=> C6 + Li+ + e^-</chem>

The positive electrode half-reaction in the lithium-doped cobalt oxide substrate is
: <chem>CoO2 + Li+ + e- <=> LiCoO2</chem>

The full reaction being
: <chem>LiC6 + CoO2 <=> C6 + LiCoO2</chem>

The overall reaction has its limits. Overdischarging supersaturates [[lithium cobalt oxide]], leading to the production of [[lithium oxide]],<ref>{{Cite journal | last1 = Choi | first1 = H. C. | last2 = Jung | first2 = Y. M. | last3 = Noda | first3 = I. | last4 = Kim | first4 = S. B. | title = A Study of the Mechanism of the Electrochemical Reaction of Lithium with CoO by Two-Dimensional Soft X-ray Absorption Spectroscopy (2D XAS), 2D Raman, and 2D Heterospectral XAS−Raman Correlation Analysis | doi = 10.1021/jp030438w | journal = The Journal of Physical Chemistry B | volume = 107 | issue = 24 | pages = 5806–5811 | year = 2003 }}</ref> possibly by the following irreversible reaction:

: <chem>Li+ + e^- + LiCoO2 -> Li2O + CoO</chem>

[[Overcharging (battery)|Overcharging]] up to 5.2&nbsp;[[volts]] leads to the synthesis of cobalt (IV) oxide, as evidenced by [[x-ray diffraction]]:<ref>{{Cite journal | last1 = Amatucci | first1 = G. G. | title = {{chem|CoO|2}}, the End Member of the {{chem|Li|x|CoO|2}} Solid Solution | doi = 10.1149/1.1836594 | journal = Journal of the Electrochemical Society | volume = 143 | issue = 3 | pages = 1114–1123 | year = 1996 }}</ref>

: <chem>LiCoO2 -> Li+ + CoO2 + e^-</chem>

The [[transition metal]] in the positive electrode, cobalt ([[Cobalt|Co]]), is reduced from {{chem|Co|4+}} to {{chem|Co|3+}} during discharge, and oxidized from {{chem|Co|3+}} to {{chem|Co|4+}} during charge. The participation of [[Oxygen reduction reaction | oxygen redox]] reactions in lithium-ion battery cathodes has been explored as a mechanism to enhance capacity beyond the limits set by transition metal oxidation states. Computational studies, primarily using [[density functional theory]], have provided insights into anionic redox activity and its implications for battery performance, helping researchers design materials that optimize capacity while mitigating issues like oxygen loss and structural degradation. Advances in understanding anionic redox have led to strategies such as surface fluorination to stabilize cathode materials, thereby improving their long-term cycling stability and safety.<ref name=oxred>{{cite book  |arxiv=2408.09942 |doi=10.1007/978-3-031-47303-6_15 |chapter=Oxygen Redox in Battery Cathodes: A Brief Overview |title=Computational Design of Battery Materials |series=Topics in Applied Physics |date=2024 |last1=Assadi |first1=M. Hussein N. |last2=Hanaor |first2=Dorian A. H. |volume=150 |pages=421–435 |isbn=978-3-031-47302-9 }}</ref>

The cell's energy is equal to the voltage times the charge. Each gram of lithium represents [[Faraday's constant]]/6.941, or 13,901 coulombs. At 3&nbsp;V, this gives 41.7&nbsp;kJ per gram of lithium, or 11.6&nbsp;kWh per kilogram of lithium. This is slightly more than the [[heat of combustion]] of [[gasoline]]; however, lithium-ion batteries as a whole are still significantly heavier per unit of energy due to the additional materials used in production.

Note that the cell voltages involved in these reactions are larger than the potential at which an [[aqueous solution]]s would [[electrolysis|electrolyze]].

=== Discharging and charging ===

During discharge, lithium ions ({{chem|Li|+}}) carry the [[Electrical current|current]] within the battery cell from the negative to the positive electrode, through the non-[[Aqueous solution|aqueous]] [[electrolyte]] and separator diaphragm.<ref name="Linden-2002">Linden, David and Reddy, Thomas B. (eds.) (2002). ''Handbook of Batteries 3rd Edition''. McGraw-Hill, New York. chapter 35. {{ISBN|0-07-135978-8}}.</ref>

During charging, an external electrical power source applies an over-voltage (a voltage greater than the cell's own voltage) to the cell, forcing electrons to flow from the positive to the negative electrode. The lithium ions also migrate (through the electrolyte) from the positive to the negative electrode where they become embedded in the porous electrode material in a process known as intercalation.

Energy losses arising from electrical [[contact resistance]] at interfaces between [[electrode]] layers and at contacts with current collectors can be as high as 20% of the entire energy flow of batteries under typical operating conditions.<ref>{{cite journal| last1=Zhai| first1=C| display-authors=etal| title=Interfacial electro-mechanical behaviour at rough surfaces| journal=Extreme Mechanics Letters| year=2016| volume=9| pages=422–429| doi=10.1016/j.eml.2016.03.021| bibcode=2016ExML....9..422Z| hdl=1959.4/unsworks_60452| url=https://hal.archives-ouvertes.fr/hal-02307660/file/Interfacial%20electromechanical%20EML%20authors%20version.pdf| access-date=31 August 2020| archive-date=19 April 2021| archive-url=https://web.archive.org/web/20210419021929/https://hal.archives-ouvertes.fr/hal-02307660/file/Interfacial%20electromechanical%20EML%20authors%20version.pdf| url-status=live}}</ref>

The charging procedures for single Li-ion cells, and complete Li-ion batteries, are slightly different:

* A single Li-ion cell is charged in two stages:<ref>{{cite journal |first=H. C. |last=Chung |year=2021 |title=Charge and discharge profiles of repurposed LiFePO<sub>4</sub> batteries based on the UL 1974 standard |doi=10.1038/s41597-021-00954-3 |journal=Scientific Data |volume=8 |issue=1 |page=165 |pmid=34215731 |pmc=8253776 |bibcode=2021NatSD...8..165C}}</ref><ref>{{Cite journal |last1=Wu |first1=Xiaogang |last2=Hu |first2=Chen |last3=Du |first3=Jiuyu |last4=Sun |first4=Jinlei |date=2015 |title=Multistage CC-CV Charge Method for Li-Ion Battery |journal=Mathematical Problems in Engineering |language=en |volume=2015 |pages=1–10 |doi=10.1155/2015/294793 |issn=1024-123X|doi-access=free }}</ref>
# [[Constant current]] (CC)
# [[Voltage source|Constant voltage]] (CV)
* A Li-ion battery (a set of Li-ion cells in series) is charged in three stages:
# [[Constant current]]
# Balance (only required when cell groups become unbalanced during use)
# [[Voltage source|Constant voltage]]

During the ''constant current'' phase, the charger applies a constant current to the battery at a steadily increasing voltage, until the top-of-charge voltage limit per cell is reached.

During the ''balance'' phase, the charger/battery reduces the charging current (or cycles the charging on and off to reduce the average current) while the [[state of charge]] of individual cells is brought to the same level by a balancing circuit until the battery is balanced. Balancing typically occurs whenever one or more cells reach their top-of-charge voltage before the other(s), as it is generally inaccurate to do so at other stages of the charge cycle. This is most commonly done by passive balancing, which [[Dissipation|dissipates]] excess charge as heat via [[resistor]]s connected momentarily across the cells to be balanced. Active balancing is less common, more expensive, but more efficient, returning excess energy to other cells (or the entire pack) via a [[DC-to-DC converter|DC-DC converter]] or other circuitry. Balancing most often occurs during the constant voltage stage of charging, switching between charge modes until complete. The pack is usually fully charged only when balancing is complete, as even a single cell group lower in charge than the rest will limit the entire battery's usable capacity to that of its own. Balancing can last hours or even days, depending on the magnitude of the imbalance in the battery.

During the ''constant voltage'' phase, the charger applies a voltage equal to the maximum cell voltage times the number of cells in series to the battery, as the current gradually declines towards 0, until the current is below a set threshold of about 3% of initial constant charge current.

Periodic topping charge about once per 500 hours. Top charging is recommended to be initiated when voltage goes below {{nowrap|4.05 V/cell.}}<ref>{{Cite web |last=Manzo |first=Michelle |date=2008-01-01 |title=Performance Characterization of Lithium-Ion Batteries During LEO Cycle Life Test |url=https://ntrs.nasa.gov/api/citations/20080015780/downloads/20080015780.pdf |access-date=2025-05-28 |website=NASA Technical Reports Server |page=14 |quote=Charge at C/2 (12.5 A) to 32 V battery voltage or 4.05 V on any cell.}}</ref> 

Failure to follow current and voltage limitations can result in an explosion.<ref name="Schweber-2015"/><ref name="illinois.edu">{{cite web  | title = Design Review For: Advanced Electric Vehicle Battery Charger, ECE 445 Senior Design Project  | url =  http://courses.ece.illinois.edu/ece445/projects/fall2007/project10_design_review.doc |work=090521 courses.ece.illinois.edu |archive-url= https://web.archive.org/web/20130504121516/http://courses.ece.illinois.edu/ece445/projects/fall2007/project10_design_review.doc |archive-date=4 May 2013 }}</ref>

Charging temperature limits for Li-ion are stricter than the operating limits. Lithium-ion chemistry performs well at elevated temperatures but prolonged exposure to heat reduces battery life. Li‑ion batteries offer good charging performance at cooler temperatures and may even allow "fast-charging" within a temperature range of {{convert|5 to 45|C}}.<ref name="Lithium Ion Rechargeable Batteries">{{cite web | title = Lithium Ion Rechargeable Batteries. Technical Handbook  | url = http://www.sony.com.cn/products/ed/battery/download.pdf |archive-url= https://web.archive.org/web/20090411024100/http://www.sony.com.cn/products/ed/battery/download.pdf |archive-date=11 April 2009 }}</ref> Charging should be performed within this temperature range. At temperatures from 0 to 5&nbsp;°C charging is possible, but the charge current should be reduced. During a low-temperature (under 0&nbsp;°C) charge, the slight temperature rise above ambient due to the internal cell resistance is beneficial. High temperatures during charging may lead to battery degradation and charging at temperatures above 45&nbsp;°C will degrade battery performance, whereas at lower temperatures the internal resistance of the battery may increase, resulting in slower charging and thus longer charging times.<ref name="Lithium Ion Rechargeable Batteries"/>{{better source needed|reason=Primary source, does not include authors nor publishing date. See talk page for discussion. | date = August 2014}}

Batteries gradually self-discharge even if not connected and delivering current. Li-ion rechargeable batteries have a [[self-discharge]] rate typically stated by manufacturers to be 1.5–2% per month.<ref>[http://www.rathboneenergy.com/articles/sanyo_lionT_E.pdf Sanyo: Overview of Lithium Ion Batteries]. {{webarchive  | url = https://web.archive.org/web/20160303212922/http://www.rathboneenergy.com/articles/sanyo_lionT_E.pdf  | date = 3 March 2016 }}, listing self-discharge rate of 2%/mo.</ref><ref>[http://www.hardingenergy.com/pdfs/5%20Lithium%20Ion.pdf Sanyo: Harding energy specification]. {{webarchive  | url = https://web.archive.org/web/20151227093854/http://www.hardingenergy.com/pdfs/5%20Lithium%20Ion.pdf  | date = 27 December 2015 }}, listing self-discharge rate of 0.3%/mo.</ref>

The rate increases with temperature and state of charge. A 2004 study found that for most cycling conditions self-discharge was primarily time-dependent; however, after several months of stand on open circuit or float charge, state-of-charge dependent losses became significant. The self-discharge rate did not increase monotonically with state-of-charge, but dropped somewhat at intermediate states of charge.<ref>{{Cite journal | last1 = Zimmerman | first1 = A. H. | title = Self-discharge losses in lithium-ion cells | doi = 10.1109/MAES.2004.1269687 | journal = IEEE Aerospace and Electronic Systems Magazine | volume = 19 | issue = 2 | pages = 19–24 | year = 2004 | s2cid = 27324676 }}</ref> Self-discharge rates may increase as batteries age.<ref name="Weicker-2013">{{cite book |author=Weicker, Phil  | title = A Systems Approach to Lithium-Ion Battery Management  | url = {{google books |plainurl=y |id=pXIiAgAAQBAJ |page=214}}  | date = 1 November 2013 |publisher=Artech House |isbn=978-1-60807-659-8 |page=214}}</ref> In 1999, self-discharge per month was measured at 8% at 21&nbsp;°C, 15% at 40&nbsp;°C, 31% at 60&nbsp;°C.<ref>{{Cite journal | last1 = Abe | first1 = H. | last2 = Murai | first2 = T. | last3 = Zaghib | first3 = K. | doi = 10.1016/S0378-7753(98)00158-X | title = Vapor-grown carbon fiber anode for cylindrical lithium ion rechargeable batteries | journal = Journal of Power Sources | volume = 77 | issue = 2 | pages = 110–115 | year = 1999 | bibcode = 1999JPS....77..110A | s2cid = 98171072 }}</ref> By 2007, monthly self-discharge rate was estimated at 2% to 3%, and 2<ref name="Redondo-Iglesias-2016">{{cite book |doi=10.1109/VPPC.2016.7791723 |chapter=Measuring Reversible and Irreversible Capacity Losses on Lithium-Ion Batteries |title=2016 IEEE Vehicle Power and Propulsion Conference (VPPC) |page=7 |year=2016 |last1=Redondo-Iglesias |first1=Eduardo |last2=Venet |first2=Pascal |last3=Pelissier |first3=Serge |isbn=978-1-5090-3528-1 |s2cid=22822329 |chapter-url=https://hal.archives-ouvertes.fr/hal-01393614/document |url=https://hal.archives-ouvertes.fr/hal-01393614 |access-date=20 October 2017 |archive-date=28 April 2021 |archive-url=https://web.archive.org/web/20210428034748/https://hal.archives-ouvertes.fr/hal-01393614 |url-status=live }}</ref>–3% by 2016.<ref>{{cite book |last1=Vetter |first1=Matthias |title=Storing Energy |last2=Lux |first2=Stephan |chapter-url=http://scitechconnect.elsevier.com/wp-content/uploads/2017/01/3-s2.0-B9780128034408000117-main.pdf |department=Fraunhofer Institute for Solar Energy Systems ISE |page=205 |doi=10.1016/B978-0-12-803440-8.00011-7 |chapter=Rechargeable Batteries with Special Reference to Lithium-Ion Batteries |year=2016 |isbn=978-0-12-803440-8 |access-date=20 October 2017 |archive-date=21 October 2017 |archive-url=https://web.archive.org/web/20171021060517/http://scitechconnect.elsevier.com/wp-content/uploads/2017/01/3-s2.0-B9780128034408000117-main.pdf |url-status=live }}</ref>

By comparison, the self-discharge rate for [[Nickel–metal hydride battery|NiMH batteries]] dropped, as of 2017, from up to 30% per month for previously common cells<ref name="Winter-2004a"/> to about 0.08–0.33% per month for [[Low self-discharge NiMH battery#Low self-discharge cells|low self-discharge NiMH]] batteries, and is about 10% per month in [[nickel–cadmium battery|NiCd batteries]].{{citation needed | date = October 2017}}

=== Cathode ===

Transition metal oxides (TMOs) are widely used as cathode materials in lithium-ion batteries as the variable oxidation state of transition metal cations allows oxides of these metals to reversibly host lithium ions (Li⁺) and undergo efficient redox (reduction-oxidation) reactions. Their layered or framework structures allow Li⁺ insertion/extraction during charging/discharging, while their transition metals and oxygen anions participate in electron transfer, enabling high energy density and stability.<ref name=cdbm>{{cite book | editor-last=Hanaor | editor-first=D.A. | date=2024 | title=Computational Design of Battery Materials | publisher=Springer | isbn=9783031473036}}</ref> There are three classes of commercial cathode materials in lithium-ion batteries: (1) layered oxides, (2) spinel oxides and (3) oxoanion complexes. All of them were discovered by John Goodenough and his collaborators.<ref name="Manthiram-2020" />

==== Layered Oxides ====
[[LiCoO2|LiCoO<sub>2</sub>]] was used in the first commercial lithium-ion battery made by Sony in 1991. The layered oxides have a pseudo-[[Tetrahedron|tetrahedral]] structure comprising layers made of MO<sub>6</sub> [[Octahedron|octahedra]] separated by interlayer spaces that allow for two-dimensional lithium-ion [[diffusion]].{{Citation needed|date=January 2024}} The [[Electronic band structure|band structure]] of Li<sub>x</sub>CoO<sub>2</sub> allows for true [[Electrical resistivity and conductivity|electronic]] (rather than [[polaron]]ic) conductivity. However, due to an overlap between the Co<sup>4+</sup> t<sub>2g</sub> d-band with the O<sup>2-</sup> 2p-band, the x must be >0.5, otherwise O<sub>2</sub> evolution occurs. This limits the charge capacity of this material to ~140 mA h g<sup>−1</sup>.<ref name="Manthiram-2020">{{Cite journal |last=Manthiram |first=Arumugam |date=2020-03-25 |title=A reflection on lithium-ion battery cathode chemistry |journal=Nature Communications |language=en |volume=11 |issue=1 |page=1550 |doi=10.1038/s41467-020-15355-0 |issn=2041-1723 |pmc=7096394 |pmid=32214093|bibcode=2020NatCo..11.1550M }}</ref>

Several other first-row (3d) [[transition metal]]s also form layered LiMO<sub>2</sub> salts. Some can be directly prepared from [[lithium oxide]] and M<sub>2</sub>O<sub>3</sub> (e.g. for M=Ti, V, Cr, Co, Ni), while others (M= Mn or Fe) can be prepared by [[ion exchange]] from NaMO<sub>2</sub>. LiVO<sub>2</sub>, LiMnO<sub>2</sub> and LiFeO<sub>2</sub> suffer from structural instabilities (including mixing between M and Li sites) due to a low energy difference between octahedral and tetrahedral environments for the metal ion M. For this reason, they are not used in lithium-ion batteries.<ref name="Manthiram-2020" /> However, Na<sup>+</sup> and Fe<sup>3+</sup> have sufficiently different sizes that NaFeO<sub>2</sub> can be used in [[sodium-ion batteries]].<ref>Okada, S. and Yamaki, J.-I. (2009). Iron-Based Rare-Metal-Free Cathodes. In Lithium Ion Rechargeable Batteries, K. Ozawa (Ed.). 
https://onlinelibrary.wiley.com/doi/10.1002/9783527629022.ch4 {{Webarchive|url=https://web.archive.org/web/20231005154711/https://onlinelibrary.wiley.com/doi/10.1002/9783527629022.ch4 |date=5 October 2023 }}</ref>

Similarly, LiCrO<sub>2</sub> shows reversible lithium (de)intercalation around 3.2&nbsp;V with 170–270&nbsp;mAh/g.<ref>Electrochemical performance of CrOx cathode material for high energy density lithium batteries. 2023. Int J Electrochem Sci. 18/2, 44. D. Liu, X. Mu, R. Guo, J. Xie, G. Yin, P. Zuo. doi: 10.1016/j.ijoes.2023.01.020.</ref> However, its [[Charge cycle|cycle]] life is short, because of [[disproportionation]] of Cr<sup>4+</sup> followed by translocation of Cr<sup>6+</sup> into tetrahedral sites.<ref>Industrialization of Layered Oxide Cathodes for Lithium-Ion and Sodium-Ion Batteries: A Comparative Perspective. 2020. Energy Technol. 8/12, 13. J. Darga, J. Lamb, A. Manthiram. doi: 10.1002/ente.202000723.</ref> On the other hand, NaCrO<sub>2</sub> shows a much better cycling stability.<ref>K. Kubota, S. Kumakura, Y. Yoda, K. Kuroki, S. Komaba, Adv. Energy Mater. 2018, 8,
1703415</ref> LiTiO<sub>2</sub> shows Li+ (de)intercalation at a voltage of ~1.5 V, which is too low for a cathode material.

These problems leave {{chem|LiCoO|2}} and {{chem|LiNiO|2}} as the only practical layered oxide materials for lithium-ion battery cathodes.  The cobalt-based cathodes show high theoretical specific (per-mass) charge capacity, high volumetric capacity, low self-discharge, high discharge voltage, and good cycling performance. Unfortunately, they suffer from a high cost of the material.<ref name="Nitta-2015">{{cite journal|last1=Nitta|first1=Naoki|last2=Wu|first2=Feixiang|last3=Lee|first3=Jung Tae|last4=Yushin|first4=Gleb|author4-link=Gleb Yushin| title = Li-ion battery materials: present and future|journal=Materials Today | date = 2015|volume=18|issue=5 | doi = 10.1016/j.mattod.2014.10.040|pages=252–264|doi-access=free}}</ref> For this reason, the current trend among lithium-ion battery manufacturers is to switch to cathodes with higher Ni content and lower Co content.<ref>{{cite journal|last1=Fergus|first1=Jeffrey | title = Recent developments in cathode materials for lithium ion batteries|journal=Journal of Power Sources | date = 2010|volume=195|issue=4 | doi = 10.1016/j.jpowsour.2009.08.089|pages=939–954|bibcode=2010JPS...195..939F}}</ref>

In addition to a lower (than cobalt) cost, nickel-oxide based materials benefit from the two-electron redox chemistry of Ni: in layered oxides comprising nickel (such as nickel-cobalt-manganese [[Lithium nickel manganese cobalt oxides|NCM]] and nickel-cobalt-aluminium oxides [[Lithium nickel cobalt aluminium oxides|NCA]]), Ni cycles between the oxidation states +2 and +4 (in one step between +3.5 and +4.3 V),<ref>Ohzuku, T., Ueda, A. & Nagayama, M. Electrochemistry and structural chemistry of {{chem2|LiNiO2}} (R3m) for 4 volt secondary lithium cells. J. Electrochem. Soc. 140, 1862–1870 (1993).</ref><ref name="Manthiram-2020" /> cobalt- between +2 and +3, while Mn (usually >20%)  and Al (typically, only 5% is needed)<ref>W. Li, E.M. Erickson, A. Manthiram, Nat. Energy 5 (2020) 26–34</ref> remain in +4 and 3+, respectively. Thus increasing the Ni content increases the cyclable charge. For example, NCM111 shows 160&nbsp;mAh/g, while {{chem2|LiNi0.8Co0.1Mn0.1O2}} (NCM811) and {{chem2|LiNi0.8Co0.15Al0.05O2}} (NCA) deliver a higher capacity of ~200 mAh/g.<ref>Nickel-rich layered oxide cathodes for lithium-ion batteries: Failure mechanisms and modification strategies. 2023. J Energy Storage. 58/. X. Zheng, Z. Cai, J. Sun, J. He, W. Rao, J. Wang, et al. doi: 10.1016/j.est.2022.106405 ; W. Li, E.M. Erickson, A. Manthiram, Nat. Energy 5 (2020) 26–34</ref> NCM and NCA batteries are collectively called Ternary Lithium Batteries.<ref>{{cite web |title=Ternary Lithium Batteries |url=https://manlybattery.com/unlocking-ternary-lithium-battery-secrets/#1_Understanding_the_Power_of_Ternary_Lithium_Batteries |website=Manly Battery Company |date=10 August 2023 |access-date=5 May 2025}}</ref><ref>{{cite web |title=Comparative Analysis: Ternary Lithium Battery Pros and Cons |url=https://www.ufinebattery.com/blog/comparative-analysis-ternary-lithium-battery-pros-and-cons/ |website=UFine Blog |publisher=Ufine Battery |access-date=5 May 2025}}</ref>

It is worth mentioning so-called "lithium-rich" cathodes, that can be produced from traditional NCM ({{chem2|LiMO2}}, where M=Ni, Co, Mn) layered cathode materials upon cycling them to voltages/charges corresponding to Li:M<0.5. Under such conditions a new semi-reversible redox transition at a higher voltage with ca. 0.4-0.8 electrons/metal site charge appears. This transition involves non-binding electron orbitals centered mostly on O atoms. Despite significant initial interest, this phenomenon did not result in marketable products because of the fast structural degradation (O2 evolution and lattice rearrangements) of such "lithium-rich" phases.<ref>{{cite journal|last1=Xies|first1=Ying | title = Li-rich layered oxides: Structure, capacity and voltage fading mechanisms and solving strategies|journal=Particuology | date = 2022|volume=61|issue=4 |doi = 10.1016/j.partic.2021.05.011|pages=1–10|s2cid=237933219 |doi-access=free}}</ref>

==== Cubic oxides (spinels) ====
[[Lithium ion manganese oxide battery|LiMn<sub>2</sub>O<sub>4</sub>]] adopts a cubic lattice, which allows for three-dimensional lithium-ion diffusion.<ref name="SigmaAldrich">{{cite web |title=Lithium-Ion Batteries |url=http://www.sigmaaldrich.com/materials-science/material-science-products.html?TablePage=106039040 |website=Sigma Aldrich |access-date=5 November 2015 |archive-date=5 January 2016 |archive-url=https://web.archive.org/web/20160105023031/http://www.sigmaaldrich.com/materials-science/material-science-products.html?TablePage=106039040 |url-status=live }}</ref> Manganese cathodes are attractive because manganese is less expensive than cobalt or nickel. The operating voltage of Li-LiMn<sub>2</sub>O<sub>4</sub> battery is 4&nbsp;V, and ca. one lithium per two Mn ions can be reversibly extracted from the tetrahedral sites, resulting in a practical capacity of <130 mA h g–1. However, Mn<sup>3+</sup> is not a stable oxidation state, as it tends to [[disproportionation|disporportionate]] into insoluble Mn<sup>4+</sup> and soluble Mn<sup>2+</sup>.<ref name="Nitta-2015"/><ref name="Nature-2020">A reflection on lithium-ion battery cathode chemistry. 2020. Nature Communications. 11/1, 9. A. Manthiram. doi: 10.1038/s41467-020-15355-0</ref> LiMn<sub>2</sub>O<sub>4</sub> can also intercalate more than 0.5 Li per Mn at a lower voltage around +3.0 V. However, this results in an irreversible [[phase transition]] due to [[Jahn-Teller]] distortion in Mn3+:t2g3eg1,  as well as [[disproportionation]] and dissolution of Mn<sup>3+</sup>.

An important improvement of Mn spinel are related cubic structures of the LiMn<sub>1.5</sub>Ni<sub>0.5</sub>O<sub>4</sub> type, where  Mn exists as Mn4+ and Ni cycles reversibly between the [[oxidation states]] +2 and +4.<ref name="Manthiram-2020" /> This materials show a reversible Li-ion capacity of  ca. 135&nbsp;mAh/g around 4.7&nbsp;V. Although such high voltage is beneficial for increasing the [[specific energy]] of batteries, the adoption of such materials is currently hindered by the lack of suitable high-voltage electrolytes.<ref>Nickel-rich layered oxide cathodes for lithium-ion batteries: Failure mechanisms and modification strategies. 2023. J Energy Storage. 58/. X. Zheng, Z. Cai, J. Sun, J. He, W. Rao, J. Wang, et al. doi: 10.1016/j.est.2022.106405.</ref> In general, materials with a high [[nickel]] content are favored in 2023, because of the possibility of a 2-electron cycling of Ni between the [[oxidation states]] +2 and +4.

LiV<sub>2</sub>O<sub>4</sub> (lithium vanadium oxide) operates as a lower (ca. +3.0&nbsp;V) voltage than [[Lithium ion manganese oxide battery|LiMn<sub>2</sub>O<sub>4</sub>]], suffers from similar durability issues, is more expensive, and thus is not considered of practical interest.<ref>de Picciotto, L. A. & Thackeray, M. M. Insertion/extraction reactions of
lithium with LiV2O4. Mater. Res. Bull. 20, 1409–1420 (1985)</ref>

==== Oxoanionic/olivins ====
Around 1980 [[Manthiram]] discovered that [[oxoanions]] ([[molybdates]] and [[tungstates]] in that particular case) cause a substantial positive shift in the redox potential of the metal-ion compared to oxides.<ref>Gopalakrishnan, J. & Manthiram, A. Topochemically controlled hydrogen reduction of scheelite-related rare-earth metal molybdates. Dalton Trans. 3, 668–672 (1981) due to the [[inductive effect]]</ref> In addition, these oxoanionic cathode materials offer better stability/safety than the corresponding oxides. However, they also suffer from poor electronic conductivity due to the long distance between redox-active metal centers, which slows down the electron transport. This necessitates the use of small (less than 200&nbsp;nm) cathode particles and coating each particle with a layer of electronically-[[conductive agent|conducting carbon]].<ref>{{cite journal|last1=Eftekhari|first1=Ali | title = LiFePO<sub>4</sub>/C Nanocomposites for Lithium-Ion Batteries|journal=Journal of Power Sources | date = 2017|volume=343 | doi = 10.1016/j.jpowsour.2017.01.080|pages=395–411|bibcode=2017JPS...343..395E}}</ref> This reduces the [[packing density]] of these materials.

Although numerous combinations of oxoanions ([[sulfate]], [[phosphate]], [[silicate]]) with various metals (mostly Mn, Fe, Co, Ni) have been studied, [[LiFePO4]] is the only one that has been commercialized. Although it was originally used primarily for [[stationary energy storage]] due to its lower energy density compared to layered oxides,<ref name="Olivetti-2017">{{Cite journal |last1=Olivetti |first1=Elsa A. |last2=Ceder |first2=Gerbrand |last3=Gaustad |first3=Gabrielle G. |last4=Fu |first4=Xinkai |date=October 2017 |title=Lithium-Ion Battery Supply Chain Considerations: Analysis of Potential Bottlenecks in Critical Metals |url=https://linkinghub.elsevier.com/retrieve/pii/S2542435117300442 |journal=Joule |language=en |volume=1 |issue=2 |pages=229–243 |doi=10.1016/j.joule.2017.08.019|bibcode=2017Joule...1..229O }}</ref> it has begun to be widely used in electric vehicles since the 2020s.<ref name="Lienert-2023">{{Cite news |last=Lienert |first=Paul |date=June 23, 2023 |title=For EV batteries, lithium iron phosphate narrows the gap with nickel, cobalt |url=https://www.reuters.com/business/autos-transportation/ev-batteries-lithium-iron-phosphate-narrows-gap-with-nickel-cobalt-2023-06-22/ |access-date=2024-11-10 |work=Reuters}}</ref>

{| class="wikitable sortable"
|+ Positive electrode
! Technology!! Major producers (2023)!! Target application !! Advantages
|-
|[[Lithium nickel manganese cobalt oxides|Lithium nickel manganese cobalt oxide]]<br />'''NMC''', LiNi{{sub|x}}Mn{{sub|y}}Co{{sub|z}}O{{sub|2}}
|style="max-width:0;" | [[Ronbay Technology]], Easpring, Ecopro, [[Umicore]], L&F, [[POSCO Future M|Posco]]<ref name="Hettesheimer-2023">{{Cite report |url=https://publica.fraunhofer.de/handle/publica/456809 |title=Lithium-Ion Battery Roadmap - Industrialization Perspectives toward 2030 |last1=Hettesheimer |first1=Tim |last2=Neef |first2=Christoph |date=2023 |publisher=[[Fraunhofer Institute for Systems and Innovation Research]] |doi=10.24406/publica-2153 |language=en |last3=Rosellón Inclán |first3=Inés |last4=Link |first4=Steffen |last5=Schmaltz |first5=Thomas |last6=Schuckert |first6=Felix |last7=Stephan |first7=Annegret |last8=Stephan |first8=Maximilian |last9=Thielmann |first9=Axel |access-date=2024-11-10}}</ref>
|[[Electric vehicle]]s, [[power tool]]s, [[grid energy storage]]
|Good specific energy and specific power density
|-
|[[Lithium nickel cobalt aluminium oxides|Lithium nickel cobalt aluminium oxide]]<br />'''NCA''', LiNiCoAlO{{sub|2}}
|Ronbay Technology, Ecopro<ref name="Hettesheimer-2023" />
|[[Electric vehicle]]s, [[power tool]]s, [[grid energy storage]]
|High energy density, good life span
|-
|Lithium nickel cobalt manganese aluminium oxide<br />'''NCMA''', {{chem|Li|Ni|0.89|Co|0.05|Mn|0.05|Al|0.01|O|2}}
|style="max-width:0;" | [[LG Chem]],<ref>{{cite news |url=https://www.reuters.com/business/lg-chem-invest-more-than-3-bln-build-battery-cathode-plant-us-2022-11-21/ |title=LG Chem to invest over $3 billion to build U.S. battery cathode plant |author=Yang, Heekyong |date=November 22, 2022 |work=Reuters |access-date=25 July 2023 |archive-date=25 July 2023 |archive-url=https://web.archive.org/web/20230725153039/https://www.reuters.com/business/lg-chem-invest-more-than-3-bln-build-battery-cathode-plant-us-2022-11-21/ |url-status=live }}</ref> [[Hanyang University]]<ref>{{cite journal |doi=10.1021/acsenergylett.8b02499 |title=Quaternary Layered Ni-Rich NCMA Cathode for Lithium-Ion Batteries |author1=Kim, Un-Hyuck |author2=Kuo, Liang-Yin |author3=Kaghazchi, Payam |author4=Yoon, Chong S. |author5=Sun, Yang-Kook |date=January 25, 2019 |volume=4 |issue=2 |journal=ACS Energy Lett. |publisher=American Chemical Society |pages=576–582|s2cid=139505460 |doi-access=free }}</ref>
|[[Electric vehicle]]s, [[grid energy storage]]
|Good specific energy, improved long-term cycling stability, faster charging
|-
|[[Lithium ion manganese oxide battery|Lithium manganese oxide]]<br />'''LMO''', LiMn{{sub|2}}O{{sub|4}}
|style="max-width:0;" |Posco, L&F<ref name="Hettesheimer-2023" />
|Power tools, electric vehicles<ref>{{Cite web |last=Elgendy |first=Mohamed |date=2024-02-07 |title=Exploring The Role of Manganese in Lithium-Ion Battery Technology |url=https://www.azom.com/article.aspx?ArticleID=23388 |access-date=2024-11-10 |website=AZoM |language=en}}</ref>
|Fast charging speed, cheap
|-
| [[Lithium iron phosphate battery|Lithium iron phosphate]]<br />'''LFP''', LiFePO{{sub|4}}
| style="max-width:0" | [[Shenzhen Dynanonic]], [[Hunan Yuneng]], LOPAL, Ronbay Technology<ref name="Hettesheimer-2023" />
| style="max-width:0" | [[Electric vehicle]]s,<ref name="Lienert-2023" /> grid energy storage<ref name="Olivetti-2017" />
| style="max-width:0" | Higher safety compared to layered oxides. Very long cycle life. Thermal stability >{{convert|60|C|F}}
|-
|[[Lithium cobalt oxide]]<br />'''LCO''', LiCoO{{sub|2}}
|Easpring, Umicore<ref name="Hettesheimer-2023" />
|[[Mobile device|Handheld electronics]]<ref name="Hettesheimer-2023" />
|High energy density
|}

=== Anode ===
{{main|Research in lithium-ion batteries#Anode}}

Negative electrode materials are traditionally constructed from graphite and other carbon materials, although newer silicon-based materials are being increasingly used (see [[Nanowire battery]]). In 2016, 89% of lithium-ion batteries contained graphite (43% artificial and 46% natural), 7% contained amorphous carbon (either soft carbon or [[hard carbon]]), 2% contained lithium titanate (LTO) and 2% contained silicon or tin-based materials.<ref>{{Cite journal |last1=Linsenmann |first1=Fabian |last2=Pritzl |first2=Daniel |last3=Gasteiger |first3=Hubert A. |date=2021-01-01 |title=Comparing the Lithiation and Sodiation of a Hard Carbon Anode Using In Situ Impedance Spectroscopy |journal=Journal of the Electrochemical Society |volume=168 |issue=1 |page=010506 |doi=10.1149/1945-7111/abd64e |bibcode=2021JElS..168a0506L |s2cid=234306808 |issn=0013-4651|doi-access=free }}</ref>

These materials are used because they are abundant, electrically conducting and can intercalate lithium ions to store electrical charge with modest volume expansion (~10%).<ref name="Hayner-2012">{{Cite journal | date = 1 January 2012 | title = Materials for Rechargeable Lithium-Ion Batteries|journal=Annual Review of Chemical and Biomolecular Engineering|volume=3|issue=1|pages=445–471 | doi = 10.1146/annurev-chembioeng-062011-081024|pmid=22524506 | last1 = Hayner | first1 = CM | last2 = Zhao | first2 = X | last3 = Kung | first3 = HH}}</ref> Graphite is the dominant material because of its low intercalation voltage and excellent performance. Various alternative materials with higher capacities have been proposed, but they usually have higher voltages, which reduces energy density.<ref>{{Cite journal | date = 2017 | title = Low Voltage Anode Materials for Lithium-Ion Batteries | doi = 10.1016/j.ensm.2017.01.009|journal=Energy Storage Materials|volume=7|pages=157–180 | last1 = Eftekhari | first1 = Ali| bibcode = 2017EneSM...7..157E }}</ref> Low voltage is the key requirement for anodes; otherwise, the excess capacity is useless in terms of energy density.

{| class="wikitable sortable"
|+ Negative electrode
! Technology !! Energy density !! Durability !! Company !! Target application !! Comments
|-
| Graphite
| 260 Wh/kg || || [[Tesla, Inc.|Tesla]]
| style="max-width:0;" | The dominant negative electrode material used in lithium-ion batteries, limited to a capacity of 372&nbsp;mAh/g.<ref name="Shao-2020" />
| style="max-width:0;" | Low cost and good energy density. Graphite anodes can accommodate one lithium atom for every six carbon atoms. Charging rate is governed by the shape of the long, thin graphene sheets that constitute graphite. While charging, the lithium ions must travel to the outer edges of the graphene sheet before coming to rest (intercalating) between the sheets. The circuitous route takes so long that they encounter congestion around those edges.<ref name="Electroiq.com-2018">{{cite web  | url = http://electroiq.com/blog/2011/11/northwestern-researchers-advance-li-ion-battery-with-graphene-silicon-sandwich/  | title = Northwestern researchers advance Li-ion batteries with graphene-silicon sandwich {{pipe}} Solid State Technology |publisher=Electroiq.com  | date = November 2011 |access-date=3 January 2019 |archive-url=https://web.archive.org/web/20180315064945/http://electroiq.com/blog/2011/11/northwestern-researchers-advance-li-ion-battery-with-graphene-silicon-sandwich/ |archive-date=15 March 2018 }}<br />{{Cite journal | doi = 10.1002/aenm.201100426| title = In-Plane Vacancy-Enabled High-Power Si-Graphene Composite Electrode for Lithium-Ion Batteries| journal = Advanced Energy Materials| volume = 1| issue = 6| pages = 1079–1084| year = 2011| last1 = Zhao | first1 = X. | last2 = Hayner | first2 = C. M. | last3 = Kung | first3 = M. C. | last4 = Kung | first4 = H. H. | s2cid = 98312522| doi-access = free| bibcode = 2011AdEnM...1.1079Z}}</ref>
|-
| Lithium&nbsp;titanate<br />'''LTO''', Li{{sub|4}}Ti{{sub|5}}O{{sub|12}} || || || style="max-width:0;" | Toshiba, [[Altairnano]] || style="max-width:0;" | Automotive ([[Phoenix Motorcars]]), electrical grid (PJM Interconnection Regional Transmission Organization control area,<ref>{{cite press release  | url = http://www.b2i.us/profiles/investor/ResLibraryView.asp?ResLibraryID=27574&GoTopage=1&BzID=546&Category=1183&a=  | title = ... Acceptance of the First Grid-Scale, Battery Energy Storage System |publisher=Altair Nanotechnologies  | date = 21 November 2008 |access-date=8 October 2009 |archive-date=3 August 2020 |archive-url=https://web.archive.org/web/20200803203141/http://www.b2i.us/profiles/investor/ResLibraryView.asp?ResLibraryID=27574&GoTopage=1&BzID=546&Category=1183&a= }}</ref> [[United States Department of Defense]]<ref>Ozols, Marty (11 November 2009). [http://systemagicmotives.com/Altairnative%20Site/Power/Power%20Partners/The%20DOD.htm Altair Nanotechnologies Power Partner – The Military] {{Webarchive|url=https://web.archive.org/web/20110716181133/http://systemagicmotives.com/Altairnative%20Site/Power/Power%20Partners/The%20DOD.htm |date=16 July 2011 }}. Systemagicmotives (personal webpage){{Dubious | date = June 2010}}. Retrieved 11 June 2010.</ref>), bus (Proterra) || Improved output, charging time, durability (safety, operating temperature {{convert|-50|-|70|C|F}}).<ref>{{cite web | url = http://www.altairnano.com/documents/AltairnanoEDTAPresentation.pdf |archive-url=https://web.archive.org/web/20070616083647/http://www.altairnano.com/documents/AltairnanoEDTAPresentation.pdf |archive-date=16 June 2007  | title = Altair EDTA Presentation |publisher=Altairnano.com  | date = 29 November 2006|author=Gotcher, Alan J. }}</ref>
|-
| Hard carbon
| || || Energ2<ref>[http://www.technologyreview.com/news/512961/designer-carbon-provides-longer-battery-life/ Synthetic Carbon Negative electrode Boosts Battery Capacity 30 Percent {{!}} MIT Technology Review]. Technologyreview.com (2 April 2013). Retrieved 16 April 2013. {{Webarchive|url=https://web.archive.org/web/20130404000033/http://www.technologyreview.com/news/512961/designer-carbon-provides-longer-battery-life/ |date=4 April 2013 }}</ref>
| Home electronics
| Greater storage capacity.
|-
| Tin/cobalt alloy
| || || Sony
| Consumer electronics (Sony Nexelion battery)
| Larger capacity than a cell with graphite (3.5 Ah 18650-type cell).
|-
| Silicon/carbon
| {{nowrap|730 Wh/L}}<br />450&nbsp;Wh/kg
|
| Amprius<ref>{{Cite web|last=Blain|first=Loz|date=2022-02-14|title=Amprius ships first batch of "world's highest density" batteries|url=https://newatlas.com/energy/amprius-450-wh-kg-battery/|access-date=2022-02-14|website=New Atlas|language=en-US|archive-date=14 February 2022|archive-url=https://web.archive.org/web/20220214194713/https://newatlas.com/energy/amprius-450-wh-kg-battery/|url-status=live}}</ref>
| Smartphones, providing 5000&nbsp;mAh capacity
| 
Pure Si can present a capacity density around 4200 mAh/g, but it will undergo a severe volume expansion (>300%), so it often being mixed with graphite.<ref>
TY  - JOUR
AU  - Feng, Kun
AU  - Li, Matthew
AU  - Liu, Wenwen
AU  - Kashkooli, Ali Ghorbani
AU  - Xiao, Xingcheng
AU  - Cai, Mei
AU  - Chen, Zhongwei
C7  - 1702737
TI  - Silicon-Based Anodes for Lithium-Ion Batteries: From Fundamentals to Practical Applications
JO  - Small
JA  - Small
VL  - 14
IS  - 8
SN  - 1613-6810
UR  - https://doi.org/10.1002/smll.201702737
DO  - https://doi.org/10.1002/smll.201702737
SP  - 1702737
KW  - binders
KW  - electrode engineering
KW  - electrolytes
KW  - lithium-ion batteries
KW  - silicon anodes
PY  - 2018
AB  - Abstract Silicon has been intensively studied as an anode material for lithium-ion batteries (LIB) because of its exceptionally high specific capacity. However, silicon-based anode materials usually suffer from large volume change during the charge and discharge process, leading to subsequent pulverization of silicon, loss of electric contact, and continuous side reactions. These transformations cause poor cycle life and hinder the wide commercialization of silicon for LIBs. The lithiation and delithiation behaviors, and the interphase reaction mechanisms, are progressively studied and understood. Various nanostructured silicon anodes are reported to exhibit both superior specific capacity and cycle life compared to commercial carbon-based anodes. However, some practical issues with nanostructured silicon cannot be ignored, and must be addressed if it is to be widely used in commercial LIBs. This Review outlines major impactful work on silicon-based anodes, and the most recent research directions in this field, specifically, the engineering of silicon architectures, the construction of silicon-based composites, and other performance-enhancement studies including electrolytes and binders. The burgeoning research efforts in the development of practical silicon electrodes, and full-cell silicon-based LIBs are specially stressed, which are key to the successful commercialization of silicon anodes, and large-scale deployment of next-generation high energy density LIBs.
ER  - 
</ref>
Another approach used carbon-coated 15&nbsp;nm thick crystal silicon flakes. The tested half-cell achieved 1200&nbsp;mAh/g over 800 cycles.<ref>{{Cite web|url=http://newatlas.com/silicon-sawdust-battery-anodes/48060|title=Silicon sawdust – coming soon to a battery near you?|last=Coxworth|first=Ben|date=22 February 2017|website=newatlas.com|access-date=26 February 2017|archive-date=25 February 2017|archive-url=https://web.archive.org/web/20170225183747/http://newatlas.com/silicon-sawdust-battery-anodes/48060/?|url-status=live}}</ref>
|}

As graphite is limited to a maximum capacity of 372&nbsp;mAh/g<ref name="Shao-2020" /> much research has been dedicated to the development of materials that exhibit higher theoretical capacities and overcoming the technical challenges that presently encumber their implementation. The extensive 2007 Review Article by Kasavajjula et al.<ref name="Kasavajjula-2007">{{Cite journal|last1=Kasavajjula|first1=U.|last2=Wang|first2=C.|last3=Appleby|first3=A.J. C.. | title = Nano- and bulk-silicon-based insertion anodes for lithium-ion secondary cells|journal=Journal of Power Sources |volume=163|issue=2|pages=1003–1039 | doi = 10.1016/j.jpowsour.2006.09.084|year=2007|bibcode=2007JPS...163.1003K}}</ref>
summarizes early research on silicon-based anodes for lithium-ion secondary cells. In particular, Hong Li et al.<ref name="Li-2000">{{Cite journal|last1=Li|first1=H.|last2=Huang|first2=X.|last3=Chenz|first3=L. C.|last4=Zhou|first4=G.|last5=Zhang|first5=Z. | title = The crystal structural evolution of nano-Si anode caused by lithium insertion and extraction at room temperature|journal=Solid State Ionics |volume=135|issue=1–4|pages=181–191 | doi = 10.1016/S0167-2738(00)00362-3|year=2000}}</ref> showed in 2000 that the electrochemical insertion of lithium ions in silicon [[nanoparticle]]s and silicon nanowires leads to the formation of an amorphous Li-Si alloy. The same year, Bo Gao and his doctoral advisor, Professor Otto Zhou described the cycling of electrochemical cells with anodes comprising silicon nanowires, with a reversible capacity ranging from at least approximately 900 to 1500&nbsp;mAh/g.<ref>{{Cite journal|last1=Gao|first1=B.|last2=Sinha|first2=S.|last3=Fleming|first3=L.|last4=Zhou|first4=O. | title = Alloy Formation in Nanostructured Silicon|journal=Advanced Materials|volume=13|issue=11|pages=816–819|
 doi = 10.1002/1521-4095(200106)13:11<816::AID-ADMA816>3.0.CO;2-P|year=2001|bibcode=2001AdM....13..816G }}</ref>

Diamond-like carbon coatings can increase retention capacity by 40% and cycle life by 400% for lithium based batteries.<ref>{{cite journal |last1=Zia |first1=Abdul Wasy |last2=Hussain |first2=Syed Asad |last3=Rasul |first3=Shahid |last4=Bae |first4=Dowon |last5=Pitchaimuthu |first5=Sudhagar |title=Progress in diamond-like carbon coatings for lithium-based batteries |journal=Journal of Energy Storage |date=November 2023 |volume=72 |page=108803 |doi=10.1016/j.est.2023.108803|s2cid=261197954 |doi-access=free |bibcode=2023JEnSt..7208803Z }}</ref>

To improve the stability of the lithium anode, several approaches to installing a protective layer have been suggested.<ref name="Girishkumar-2010">{{Cite journal|last1=Girishkumar|first1=G.|last2=McCloskey|first2=B.|last3=Luntz|first3=A. C.|last4=Swanson|first4=S.|last5=Wilcke|first5=W. | date = 2 July 2010 | title = Lithium−Air Battery: Promise and Challenges|journal=The Journal of Physical Chemistry Letters|volume=1|issue=14|pages=2193–2203 | doi = 10.1021/jz1005384|issn=1948-7185}}</ref> Silicon is beginning to be looked at as an anode material because it can accommodate significantly more lithium ions, storing up to 10 times the electric charge, however this alloying between lithium and silicon results in significant volume expansion (ca. 400%),<ref name="Hayner-2012" /> which causes catastrophic failure for the cell.<ref>{{cite web | title = A Better Anode Design to Improve Lithium-Ion Batteries | url = https://www-als.lbl.gov/index.php/holding/650-a-better-anode-design-to-improve-lithium-ion-batteries-.html|website=Berkeley Lab: Lawrence Berkeley National Laboratory|archive-url=https://web.archive.org/web/20160304072942/https://www-als.lbl.gov/index.php/holding/650-a-better-anode-design-to-improve-lithium-ion-batteries-.html|archive-date=4 March 2016}}</ref> Silicon has been used as an anode material but the insertion and extraction of <chem>\scriptstyle Li+</chem> can create cracks in the material. These cracks expose the Si surface to an electrolyte, causing decomposition and the formation of a solid electrolyte interphase (SEI) on the new Si surface (crumpled graphene encapsulated Si nanoparticles). This SEI will continue to grow thicker, deplete the available <chem>\scriptstyle Li+</chem>, and degrade the capacity and cycling stability of the anode.

In addition to carbon- and silicon- based anode materials for lithium-ion batteries, high-entropy metal oxide materials are being developed. These conversion (rather than intercalation) materials comprise an alloy (or subnanometer mixed phases) of several metal oxides performing different functions. For example, Zn and Co can act as electroactive charge-storing species, Cu can provide an electronically conducting support phase and MgO can prevent pulverization.<ref>O. Marques, M. Walter, E. Timofeeva, and C. Segre, Batteries, 9 115 (2023). 10.3390/batteries9020115.</ref>

=== Electrolyte ===
[[Liquid]] electrolytes in lithium-ion batteries consist of lithium [[Salt (chemistry)|salts]], such as [[lithium hexafluorophosphate|{{chem|LiPF|6}}]], [[lithium tetrafluoroborate|{{chem|LiBF|4}}]] or [[lithium perchlorate|{{chem|LiClO|4}}]] in an [[organic compound|organic]] [[solvent]], such as [[ethylene carbonate]], [[dimethyl carbonate]], and [[diethyl carbonate]].<ref>{{Cite journal |last1=Younesi |first1=Reza |last2=Veith |first2=Gabriel M. |last3=Johansson |first3=Patrik |last4=Edström |first4=Kristina |author-link4=Kristina Edström |last5=Vegge |first5=Tejs |year=2015 |title=Lithium salts for advanced lithium batteries: Li–metal, Li–O<sub>2</sub>, and Li–S |url=http://publications.lib.chalmers.se/publication/220019-lithium-salts-for-advanced-lithium-batteries-li-metal-li-o2-and-li-s |journal=Energy Environ. Sci. |volume=8 |issue=7 |pages=1905–1922 |doi=10.1039/c5ee01215e |doi-access=free|bibcode=2015EnEnS...8.1905Y }}</ref> A liquid electrolyte acts as a conductive pathway for the movement of cations passing from the negative to the positive electrodes during discharge. Typical conductivities of liquid electrolyte at room temperature ({{convert|20|C}}) are in the range of 10&nbsp;[[millisiemens|mS]]/cm, increasing by approximately 30–40% at {{convert|40|C|F}} and decreasing slightly at {{convert|0|C|F}}.<ref>Wenige, Niemann, et al. (30 May 1998). [http://www.cheric.org/PDF/Symposium/S-J2-0063.pdf Liquid Electrolyte Systems for Advanced Lithium Batteries] {{Webarchive|url=https://web.archive.org/web/20090320113501/http://www.cheric.org/PDF/Symposium/S-J2-0063.pdf |date=20 March 2009 }} (PDF). cheric.org; Chemical Engineering Research Information Center(KR). Retrieved 11 June 2010.</ref> The combination of linear and cyclic carbonates (e.g., [[ethylene carbonate]] (EC) and [[dimethyl carbonate]] (DMC)) offers high conductivity and [[Lithium–silicon battery#Solid electrolyte interphase layer|solid electrolyte interphase]] (SEI)-forming ability. While EC forms a stable SEI, it is not a liquid at room temperature, only becoming a liquid with the addition of additives such as the previously mentioned DMC or [[diethyl carbonate]] (DEC) or [[Ethyl Methyl Carbonate|ethyl methyl carbonate]] (EMC).  Organic solvents easily decompose on the negative electrodes during charge. When appropriate [[organic solvent]]s are used as the electrolyte, the solvent decomposes on initial charging and forms a solid layer called the solid electrolyte interphase,<ref>Balbuena, P.&nbsp;B., Wang, Y.&nbsp;X. (eds) (2004). ''Lithium Ion Batteries: Solid Electrolyte Interphase'', Imperial College Press, London. {{ISBN|1-86094-362-4}}.</ref> which is electrically insulating, yet provides significant ionic conductivity, behaving as a solid electrolyte. The interphase prevents further decomposition of the electrolyte after the second charge as it grows thick enough to prevent electron tunneling after the first charge cycle. For example, [[ethylene carbonate]] is decomposed at a relatively high voltage, 0.7&nbsp;V vs. lithium, and forms a dense and stable interface.<ref>{{Cite journal |last1=Fong |first1=R. A. |year=1990 |title=Studies of Lithium Intercalation into Carbons Using Nonaqueous Electrochemical Cells |journal=Journal of the Electrochemical Society |volume=137 |issue=7 |pages=2009–2010 |bibcode=1990JElS..137.2009F |doi=10.1149/1.2086855}}</ref> Composite electrolytes based on POE (poly(oxyethylene)) provide a relatively stable interface.<ref>{{Cite journal |last1=Syzdek |first1=J. A. |last2=Borkowska |first2=R. |last3=Perzyna |first3=K. |last4=Tarascon |first4=J. M. |author-link4=Jean-Marie Tarascon |last5=Wieczorek |first5=W. A. A. |year=2007 |title=Novel composite polymeric electrolytes with surface-modified inorganic fillers |journal=Journal of Power Sources |volume=173 |issue=2 |pages=712–720 |bibcode=2007JPS...173..712S |doi=10.1016/j.jpowsour.2007.05.061}}</ref><ref>{{Cite journal |last1=Syzdek |first1=J. A. |last2=Armand |first2=M. |last3=Marcinek |first3=M. |last4=Zalewska |first4=A. |last5=Żukowska |first5=G. Y. |last6=Wieczorek |first6=W. A. A. |year=2010 |title=Detailed studies on the fillers modification and their influence on composite, poly(oxyethylene)-based polymeric electrolytes |journal=Electrochimica Acta |volume=55 |issue=4 |pages=1314–1322 |doi=10.1016/j.electacta.2009.04.025}}</ref> It can be either solid (high molecular weight) and be applied in dry Li-polymer cells, or liquid (low molecular weight) and be applied in regular Li-ion cells. [[Room-temperature ionic liquid]]s (RTILs) are another approach to limiting the flammability and volatility of organic electrolytes.<ref>{{Cite journal |last1=Reiter |first1=J. |last2=Nádherná |first2=M. |last3=Dominko |first3=R. |year=2012 |title=Graphite and LiCo<sub>1/3</sub>Mn<sub>1/3</sub>Ni<sub>1/3</sub>O<sub>2</sub> electrodes with piperidinium ionic liquid and lithium bis(fluorosulfonyl)imide for Li-ion batteries |journal=Journal of Power Sources |volume=205 |pages=402–407 |doi=10.1016/j.jpowsour.2012.01.003}}</ref>

==== Solid Electrolyte Interphase (SEI) ====
The term solid electrolyte interphase was first coined by Peled in 1979 to describe the layer of insoluble products deposited on alkali and alkaline earth cathodes in non-aqueous batteries (NAB).<ref>{{Cite journal |last=Peled |first=E. |date=1979-12-01 |title=The Electrochemical Behavior of Alkali and Alkaline Earth Metals in Nonaqueous Battery Systems—The Solid Electrolyte Interphase Model |url=https://iopscience.iop.org/article/10.1149/1.2128859/meta |journal=Journal of the Electrochemical Society |language=en |volume=126 |issue=12 |page=2047 |doi=10.1149/1.2128859 |bibcode=1979JElS..126.2047P |issn=1945-7111}}</ref> However, Dey and Sullivan had noted previously in 1970 that graphite, in a lithium metal half cell using [[Propylene carbonate|propylene carbonate (PC)]], reduced the electrolyte during discharge at a rate which linearly increased with the current.<ref>{{Cite journal |last1=Dey |first1=A. N. |last2=Sullivan |first2=B. P. |date=1970-02-01 |title=The Electrochemical Decomposition of Propylene Carbonate on Graphite |url=https://iopscience.iop.org/article/10.1149/1.2407470/meta |journal=Journal of the Electrochemical Society |language=en |volume=117 |issue=2 |page=222 |doi=10.1149/1.2407470 |bibcode=1970JElS..117..222D |issn=1945-7111}}</ref> They proposed that the following reaction was taking place:

:<chem>C4H6O3 + 2e- -> CH3-CH=CH2 + CO3^{2-}</chem>

The same reaction was later proposed by Fong et al in 1990, where they theorized that the carbonate ion was reacting with the lithium to form [[lithium carbonate]], which was then forming a passivating layer on the surface of the graphite.<ref>{{Cite journal |author=Rosamaría Fong |author2=Ulrich von Sacken |author3=J. R. Dahn |title=Studies of Lithium Intercalation into Carbons Using Nonaqueous Electrochemical Cells |journal=Journal of the Electrochemical Society |date=1990 |volume=137 |issue=7 |pages=2009–2013 |doi=10.1149/1.2086855|bibcode=1990JElS..137.2009F }}</ref> PC is no longer used in batteries today as the molecules can intercalate into the graphite layers and react with the lithium there to form propylene and acts to delaminate the graphite.

The insulating properties of the SEI allow the battery to reach more extreme voltage gaps without simply reducing the electrolyte.<ref>{{Cite journal |last1=Goodenough |first1=John B. |last2=Kim |first2=Youngsik |date=2010-02-09 |title=Challenges for Rechargeable Li Batteries |url=https://pubs.acs.org/doi/10.1021/cm901452z |journal=Chemistry of Materials |volume=22 |issue=3 |pages=587–603 |doi=10.1021/cm901452z |issn=0897-4756}}</ref> This ability of the SEI to improve the voltage window of batteries was discovered almost on accident, but plays a vital role in high voltage batteries today.

==== Solid Electrolytes ====
Recent advances in battery technology involve using a solid as the electrolyte material. The most promising of these are ceramics.<ref>{{Cite journal |last1=Can |first1=Cao |last2=Zhuo-Bin |first2=Li |last3=Xiao-Liang |first3=Wang |year=2014 |title=Recent Advances in Inorganic Solid Electrolytes for Lithium Batteries |journal=Frontiers in Energy Research |volume=2 |pages=1–10 |doi=10.3389/fenrg.2014.00025 |doi-access=free|bibcode=2014FrER....2...25C }}</ref> Solid ceramic electrolytes are mostly lithium metal [[oxide]]s, which allow lithium-ion transport through the solid more readily due to the intrinsic lithium. The main benefit of solid electrolytes is that there is no risk of [[Battery leakage|leaks]], which is a serious safety issue for batteries with liquid electrolytes.<ref>{{Cite web |last=Zogg |first=Cornelia |date=14 June 2017 |title=A solid-state electrolyte that is able to compete with liquid electrolytes for rechargeable batteries |url=https://phys.org/news/2017-06-solid-state-electrolyte-liquid-electrolytes-rechargeable.html |access-date=24 February 2018 |website=Phys.org |archive-date=13 March 2018 |archive-url=https://web.archive.org/web/20180313201839/https://phys.org/news/2017-06-solid-state-electrolyte-liquid-electrolytes-rechargeable.html |url-status=live }}</ref> Solid ceramic electrolytes can be further broken down into two main categories: ceramic and glassy. [[Ceramic]] solid electrolytes are highly ordered compounds with [[crystal structure]]s that usually have ion transport channels.<ref>{{Cite journal |last1=Can |first1=Cao |last2=Zhuo-Bin |first2=Li |last3=Xiao-Liang |first3=Wang |year=2014 |title=Recent Advances in Inorganic Solid Electrolytes for Lithium Batteries |journal=Frontiers in Energy Research |volume=2 |pages=2–4 |doi=10.3389/fenrg.2014.00025 |doi-access=free|bibcode=2014FrER....2...25C }}</ref> Common ceramic electrolytes are lithium [[Fast-ion conductor|super ion conductors]] (LISICON) and [[Perovskite (structure)|perovskites]]. [[Glass]]y solid electrolytes are [[amorphous]] atomic structures made up of similar elements to ceramic solid electrolytes but have higher [[Ionic conductivity (solid state)|conductivities]] overall due to higher conductivity at grain boundaries.<ref>{{Cite journal |last1=Can |first1=Cao |last2=Zhuo-Bin |first2=Li |last3=Xiao-Liang |first3=Wang |year=2014 |title=Recent Advances in Inorganic Solid Electrolytes for Lithium Batteries |journal=Frontiers in Energy Research |volume=2 |pages=6–8 |doi=10.3389/fenrg.2014.00025 |doi-access=free|bibcode=2014FrER....2...25C }}</ref> Both glassy and ceramic electrolytes can be made more ionically conductive by substituting sulfur for oxygen. The larger radius of sulfur and its higher ability to be [[Polarizability|polarized]] allow higher conductivity of lithium. This contributes to conductivities of solid electrolytes are nearing parity with their liquid counterparts, with most on the order of 0.1&nbsp;mS/cm and the best at 10&nbsp;mS/cm.<ref>{{Cite journal |last1=Tatsumisago |first1=Masahiro |last2=Nagao |first2=Motohiro |last3=Hayashi |first3=Akitoshi |year=2013 |title=Recent development of sulfide solid electrolytes and interfacial modification for all-solid-state rechargeable lithium batteries |journal=Journal of Asian Ceramic Societies |volume=1 |issue=1 |page=17 |doi=10.1016/j.jascer.2013.03.005 |doi-access=free}}</ref> An efficient and economic way to tune targeted electrolytes properties is by adding a third component in small concentrations, known as an additive.<ref>{{Cite journal |last1=Haregewoin |first1=Atetegeb Meazah |last2=Wotango |first2=Aselefech Sorsa |last3=Hwang |first3=Bing-Joe |date=2016-06-08 |title=Electrolyte additives for lithium ion battery electrodes: progress and perspectives |url=https://pubs.rsc.org/en/content/articlelanding/2016/ee/c6ee00123h |journal=Energy & Environmental Science |volume=9 |issue=6 |pages=1955–1988 |doi=10.1039/C6EE00123H |bibcode=2016EnEnS...9.1955H |issn=1754-5706 |access-date=19 October 2020 |archive-date=20 October 2020 |archive-url=https://web.archive.org/web/20201020060833/https://pubs.rsc.org/en/content/articlelanding/2016/ee/c6ee00123h |url-status=live }}</ref> By adding the additive in small amounts, the bulk properties of the electrolyte system will not be affected whilst the targeted property can be significantly improved. The numerous additives that have been tested can be divided into the following three distinct categories: (1) those used for SEI chemistry modifications; (2) those used for enhancing the ion conduction properties; (3) those used for improving the safety of the cell (e.g. prevent overcharging).{{citation needed|date=September 2021}}

Electrolyte alternatives have also played a significant role, for example the [[lithium polymer battery]]. Polymer electrolytes are promising for minimizing the dendrite formation of lithium. Polymers are supposed to prevent short circuits and maintain conductivity.<ref name="Girishkumar-2010" />

The ions in the electrolyte diffuse because there are small changes in the electrolyte concentration. Linear diffusion is only considered here. The change in concentration ''c'', as a function of time ''t'' and distance ''x'', is

: <math>\frac{\partial c}{\partial t} = \frac{D}{\varepsilon} \frac{\partial ^2 c}{\partial x^2}.</math>

In this equation, ''D'' is the [[diffusion coefficient]] for the lithium ion. It has a value of {{val|7.5|e=−10|u=m<sup>2</sup>/s}} in the {{chem|LiPF|6}} electrolyte. The value for ''ε'', the porosity of the electrolyte, is 0.724.<ref>{{Cite journal | doi = 10.1021/ed300533f| title = Modeling the Lithium Ion Battery| journal = Journal of Chemical Education| volume = 90| issue = 4| pages = 453–455| year = 2013| last1 = Summerfield | first1 = J. | bibcode = 2013JChEd..90..453S}}</ref>

== Battery designs and formats ==
[[File:Nissan Leaf 012.JPG|thumb|upright=1.1|[[Nissan Leaf]]'s lithium-ion battery pack]]Lithium-ion batteries may have multiple levels of structure. Small batteries consist of a single battery cell. Larger batteries connect cells [[Series and parallel circuits|in parallel]] into a module and connect modules [[in series]] and parallel into a pack. Multiple packs may be connected [[Series and parallel circuits|in series]] to increase the voltage.<ref>{{Cite journal |last1=Lee |first1=Sang-Won |last2=Lee |first2=Kyung-Min |last3=Choi |first3=Yoon-Geol |last4=Kang |first4=Bongkoo |date=November 2018 |title=Modularized Design of Active Charge Equalizer for Li-Ion Battery Pack |url=https://ieeexplore.ieee.org/document/8310611 |journal=IEEE Transactions on Industrial Electronics |volume=65 |issue=11 |pages=8697–8706 |doi=10.1109/TIE.2018.2813997 |s2cid=49536272 |issn=0278-0046 |access-date=5 July 2023 |archive-date=21 May 2023 |archive-url=https://web.archive.org/web/20230521050133/https://ieeexplore.ieee.org/document/8310611/ |url-status=live }}</ref>

Batteries may be equipped with temperature sensors, heating/cooling systems, [[voltage regulator]] circuits, [[Tap changer|voltage taps]], and charge-state monitors. These components address safety risks like overheating and [[short circuit]]ing.<ref name="Goodwins2006-2006">{{cite news|author=Goodwins, Rupert|date=17 August 2006|title=Inside a notebook battery pack|url=https://www.zdnet.com/article/inside-a-notebook-battery-pack/|work=ZDNet|access-date=6 June 2013|archive-date=24 July 2013|archive-url=https://web.archive.org/web/20130724093725/http://www.zdnet.com/inside-a-notebook-battery-pack-3039281143/|url-status=live}}</ref>

=== Electrode layers and electrolyte ===
On the macrostructral level (length scale 0.1–5&nbsp;mm) almost all commercial lithium-ion batteries comprise foil current collectors (aluminium for cathode and copper for anode). Copper is selected for the anode, because lithium does not alloy with it. Aluminum is used for the cathode, because it passivates in LiPF<sub>6</sub> electrolytes.

=== Cells ===
Li-ion cells are available in various form factors, which can generally be divided into four types:{{sfn|Andrea|2010|p=2}}

* Coin cells have a rugged design with metal (stainless steel, usually) casing. Because of their poor [[specific energy]] (in Wh/kg) and small energy (Wh) per cell, their use is limited to [[handwatches]], [[portable calculators]] and research. Notably, coin format cells are more commonly used for primary [[lithium-metal batteries]].
* Small cylindrical (solid body without terminals, such as those used in most [[Electric bicycle|e-bikes]] and most [[electric vehicle battery]] and older laptop batteries); they typically come in [[List of battery sizes#Lithium-ion batteries (rechargeable)|standard sizes]].
* Large cylindrical (solid body with large threaded terminals)
* Flat or pouch (soft, flat body, such as those used in cell phones and newer laptops; these are [[lithium-ion polymer batteries]].<ref>{{cite web | title = How is a Lithium Ion Pouch Cell Manufactured in the Lab? | url = https://www.youtube.com/watch?v=f_OoK_yPVLo | publisher = KIT Zentrum für Mediales Lernen | date = 6 June 2018 | quote = Creative Commons Attribution license | access-date = 1 February 2020 | archive-date = 18 February 2020 | archive-url = https://web.archive.org/web/20200218085854/https://www.youtube.com/watch?v=f_OoK_yPVLo&gl=US&hl=en | url-status = live }}</ref>
* Rigid plastic case with large threaded terminals (such as electric vehicle traction packs)

Cells with a cylindrical shape are made in a characteristic "[[Jelly roll (battery)|swiss roll]]" manner (known as a "jelly roll" in the US), which means it is a single long "sandwich" of the positive electrode, separator, negative electrode, and separator rolled into a single spool. The result is encased in a container. One advantage of cylindrical cells is faster production speed. One disadvantage can be a large radial temperature gradient at high discharge rates.

The absence of a case gives pouch cells the highest gravimetric energy density; however, many applications require containment<!-- compression --> to prevent expansion when their [[state of charge]] (SOC) level is high,{{sfn|Andrea|2010|p=234}} and for general structural stability. Both rigid plastic and pouch-style cells are sometimes referred to as [[Prism (geometry)|prismatic]] cells due to their rectangular shapes.<ref>{{cite web  | title = Prismatic cell winder  | url = https://www.youtube.com/watch?v=Zzx6LbcRidg  | publisher = [[University of Michigan]]  | date = 25 June 2015  | access-date = 1 February 2020  | archive-date = 17 May 2020  | archive-url = https://web.archive.org/web/20200517093341/https://www.youtube.com/watch?v=Zzx6LbcRidg&gl=US&hl=en  | url-status = live  }}</ref> Three basic battery types are used in 2020s-era electric vehicles: cylindrical cells (e.g., Tesla), prismatic pouch (e.g., from [[LG Corporation|LG]]), and prismatic can cells (e.g., from LG, [[Samsung]], [[Panasonic]], and others).<!-- cylindrical cells are the least expensive to manufacture, and have been made for decades; prismatic pouches and prismatic can cells require additional infrastructure in battery pack manufacture: both prismatic types have to be compressed, need to have structure in the battery pack to hold compression so they don't delaminate in charge and discharge cycles. Cylindrical cells ("jelly roll") hold compression within each cell and are much easier to manufacture. --><ref name="Ellis-2020">{{cite AV media |url=https://www.youtube.com/watch?v=WigjD2CZAJE&t=233s |title=Sandy Munro on Tesla's Battery Tech Domination |date=4 June 2020 |medium=video |publisher=E for Electric |time=3:53–5:50 |access-date=29 June 2020 |via=YouTube |people=Mark Ellis, Sandy Munro |archive-date=7 July 2022 |archive-url=https://web.archive.org/web/20220707172944/https://www.youtube.com/watch?v=WigjD2CZAJE&t=233s |url-status=live }}</ref>

[[lithium-ion flow battery|Lithium-ion flow batteries]] have been demonstrated that suspend the cathode or anode material in an aqueous or organic solution.<ref>{{Cite journal |last1=Wang |first1=Y. |last2=He |first2=P. |last3=Zhou |first3=H. |doi=10.1002/aenm.201200100 |title=Li-Redox Flow Batteries Based on Hybrid Electrolytes: At the Cross Road between Li-ion and Redox Flow Batteries |journal=Advanced Energy Materials |volume=2 |issue=7 |pages=770–779 |year=2012 |bibcode=2012AdEnM...2..770W |s2cid=96707630}}</ref><ref>{{Cite journal |date=15 August 2016 |title=A carbon-free lithium-ion solid dispersion redox couple with low viscosity for redox flow batteries |journal=Journal of Power Sources|volume=323|pages=97–106|doi=10.1016/j.jpowsour.2016.05.033|last1=Qi |first1=Zhaoxiang|last2=Koenig|first2=Gary M.|bibcode=2016JPS...323...97Q|doi-access=free}}</ref>

As of 2014, the smallest Li-ion cell was [[pin]]-shaped with a diameter of 3.5&nbsp;mm and a weight of 0.6&nbsp;g, made by [[Panasonic]].<ref>[http://www.telecompaper.com/news/panasonic-unveils-smallest-pin-shaped-lithium-ion-battery--1041159 Panasonic unveils "smallest" pin-shaped lithium ion battery] {{Webarchive|url=https://web.archive.org/web/20150906081634/http://www.telecompaper.com/news/panasonic-unveils-smallest-pin-shaped-lithium-ion-battery--1041159 |date=6 September 2015 }}, Telecompaper, 6 October 2014</ref> A [[coin cell]] form factor is available for LiCoO<sub>2</sub> cells, usually designated with a "LiR" prefix.<ref>{{cite thesis |type=PhD |last1=Erol |first1=Salim |title=Electrochemical Impedance Spectroscopy Analysis and Modeling of Lithium Cobalt Oxide/Carbon Batteries |date=5 January 2015 |url=https://www.researchgate.net/publication/270589441 |access-date=10 September 2018}}</ref><ref name="AA-2018">{{cite web |title=Rechargeable Li-Ion Button Battery: Serial LIR2032 |publisher=AA Portable Power Corp |url=http://www.batteryspace.com/productimages/aa/20060224/LIR2032_new1.pdf |access-date=10 September 2018 |archive-date=9 May 2018 |archive-url=https://web.archive.org/web/20180509064356/http://www.batteryspace.com/productimages/aa/20060224/LIR2032_new1.pdf |url-status=live }}</ref>

=== Electrode Layers ===

==== Cell voltage ====
The average voltage of LCO (lithium cobalt oxide) chemistry is 3.6v if made with hard carbon cathode and 3.7v if made with graphite cathode. Comparatively, the latter has a flatter discharge voltage curve.<ref>{{Cite book |last=Pistoia |first=Gianfranco |url=https://books.google.com/books?id=wWciAQAAQBAJ&pg=PA25 |title=Lithium-Ion Batteries: Advances and Applications |date=2013-12-16 |publisher=Newnes |isbn=978-0-444-59516-4 |language=en}}</ref>{{Rp|pages=25–26}}

== Uses ==

Lithium ion batteries are used in a multitude of applications, including [[consumer electronics]], toys, power tools, and electric vehicles.<ref>{{Cite book |last1=OECD |url=https://books.google.com/books?id=xNdkEAAAQBAJ&pg=PA29 |title=Illicit Trade Dangerous Fakes Trade in Counterfeit Goods that Pose Health, Safety and Environmental Risks: Trade in Counterfeit Goods that Pose Health, Safety and Environmental Risks |last2=Office |first2=European Union Intellectual Property |date=2022-03-17 |publisher=OECD Publishing |isbn=978-92-64-59470-8 |language=en |access-date=10 July 2023 |archive-date=28 August 2023 |archive-url=https://web.archive.org/web/20230828175659/https://books.google.com/books?id=xNdkEAAAQBAJ&pg=PA29 |url-status=live }}</ref>

More niche uses include backup power in telecommunications applications. Lithium-ion batteries are also frequently discussed as a potential option for [[grid energy storage]],<ref>{{Cite journal|last1=Hesse|first1=Holger|last2=Schimpe|first2=Michael|last3=Kucevic |first3=Daniel|last4=Jossen|first4=Andreas|date=2017-12-11|title=Lithium-Ion Battery Storage for the Grid—A Review of Stationary Battery Storage System Design Tailored for Applications in Modern Power Grids|journal=Energies |language=en|volume=10|issue=12|page=2107|doi=10.3390/en10122107|issn=1996-1073|doi-access=free}}</ref> although as of 2020, they were not yet cost-competitive at scale.<ref>{{Cite journal|last1=Grey|first1=Clare P.|last2=Hall |first2=David S.|date=December 2020|title=Prospects for lithium-ion batteries and beyond—a 2030 vision|journal=Nature Communications|language=en|volume=11|issue=1|page=6279|doi=10.1038/s41467-020-19991-4|issn=2041-1723 |pmc=7722877|pmid=33293543|bibcode=2020NatCo..11.6279G}}</ref>

== Performance ==
{{infobox
| label1           = Specific&nbsp;energy&nbsp;density
| data1            = 100 to 250 [[watt-hour|W·h]]/kg (360 to 900 [[kilojoule|kJ]]/kg)<ref>{{cite web | title = Overview of lithium ion batteries | url = http://www.panasonic.com/industrial/includes/pdf/Panasonic_LiIon_Overview.pdf|publisher=Panasonic|archive-url=https://web.archive.org/web/20111107060525/http://www.panasonic.com/industrial/includes/pdf/Panasonic_LiIon_Overview.pdf|archive-date=7 November 2011 | date = Jan 2007|access-date=13 November 2013}}</ref>
| label2           = Volumetric energy density
| data2            = 250 to 680 W·h/[[Litre|L]] (900 to 2230 J/cm<sup>3</sup>)<ref name="greencarcongress">{{cite web  | url = http://www.greencarcongress.com/2009/12/panasonic-20091225.html  | title = Panasonic Develops New Higher-Capacity 18650 Li-Ion Cells; Application of Silicon-based Alloy in Anode  | publisher = greencarcongress.com  | access-date = 31 January 2011  | archive-date = 12 July 2014  | archive-url = https://web.archive.org/web/20140712052649/http://www.greencarcongress.com/2009/12/panasonic-20091225.html  | url-status = live  }}</ref><ref name="Quinn-2018"/>
| label3           = Specific power density
| data3            = 1 to 10,000&nbsp;W/kg<ref name="mw">{{cite web  | url = https://www.researchgate.net/figure/Specific-power-vs-specific-energy-of-Li-Ion-batteries-distinguished-by-cell-chemistry_fig2_269297116  | title = Specific power vs. specific energy of Li-Ion batteries distinguished by cell chemistry |access-date=3 November 2024}}</ref>
}}

Because lithium-ion batteries can have a variety of positive and negative electrode materials, the energy density and voltage vary accordingly.

The [[open-circuit voltage]] is higher than in [[aqueous battery|aqueous batteries]] (such as [[lead–acid battery|lead–acid]], [[nickel–metal hydride battery|nickel–metal hydride]] and [[nickel–cadmium battery|nickel–cadmium]]).<ref name="Winter-2004">{{harvnb|Winter|Brodd|2004|p=4258}}</ref>{{Failed verification | date = February 2018}} [[Internal resistance]] increases with both cycling and age,{{sfn|Andrea|2010|p=12}} although this depends strongly on the voltage and temperature the batteries are stored at.<ref>{{Cite journal|last1=Stroe|first1=Daniel-Ioan|last2=Swierczynski|first2=Maciej|last3=Kar|first3=Soren Knudsen|last4=Teodorescu|first4=Remus|date=2017-09-22|title=Degradation Behavior of Lithium-Ion Batteries During Calendar Ageing—The Case of the Internal Resistance Increase|url=https://ieeexplore.ieee.org/document/8048537|journal=IEEE Transactions on Industry Applications|volume=54|issue=1|pages=517–525|doi=10.1109/TIA.2017.2756026|s2cid=34944228|issn=0093-9994|access-date=10 February 2022|archive-date=26 January 2022|archive-url=https://web.archive.org/web/20220126210620/https://ieeexplore.ieee.org/document/8048537/|url-status=live}}</ref> Rising internal resistance causes the voltage at the terminals to drop under load, which reduces the maximum current draw. Eventually, increasing resistance will leave the battery in a state such that it can no longer support the normal discharge currents requested of it without unacceptable voltage drop or overheating.

Batteries with a lithium iron phosphate positive and graphite negative electrodes have a nominal open-circuit voltage of 3.2&nbsp;V and a typical charging voltage of 3.6&nbsp;V. Lithium nickel manganese cobalt (NMC) oxide positives with graphite negatives have a 3.7&nbsp;V nominal voltage with a 4.2&nbsp;V maximum while charging. The charging procedure is performed at constant voltage with current-limiting circuitry (i.e., charging with constant current until a voltage of 4.2&nbsp;V is reached in the cell and continuing with a constant voltage applied until the current drops close to zero). Typically, the charge is terminated at 3% of the initial charge current. In the past, lithium-ion batteries could not be fast-charged and needed at least two hours to fully charge. Current-generation cells can be fully charged in 45 minutes or less. In 2015 researchers demonstrated a small 600&nbsp;mAh capacity battery charged to 68 percent capacity in two minutes and a 3,000&nbsp;mAh battery charged to 48 percent capacity in five minutes. The latter battery has an energy density of 620&nbsp;W·h/L. The device employed heteroatoms bonded to graphite molecules in the anode.<ref>{{Cite web|title = New battery tech gives 10 hours of talk time after only 5 minutes on charge|url = http://www.gizmag.com/huawei-fast-charging-li-ion-batteries/40421|website = www.gizmag.com|access-date = 3 December 2015|first = Aaron|last = Turpen|date = 16 November 2015|archive-date = 8 December 2015|archive-url = https://web.archive.org/web/20151208232306/http://www.gizmag.com/huawei-fast-charging-li-ion-batteries/40421/|url-status = live}}</ref>

[[File:GITT-2025-03-01a.png|thumb|Galvanostatic Intermittent Titration Technique (GITT) data from an AAA(10440) size Li-ion battery.]]

Performance of manufactured batteries has improved over time. For example, from 1991 to 2005 the energy capacity per price of lithium-ion batteries improved more than ten-fold, from 0.3&nbsp;W·h per dollar to over 3&nbsp;W·h per dollar.<ref>{{cite news | url =  http://www.bloombergview.com/articles/2015-01-16/get-ready-for-life-without-oil | website =  bloombergview.com | first =  Noah | last =  Smith | title =  Get Ready For Life Without Oil | date =  16 January 2015 | access-date =  31 July 2015 | archive-date =  11 July 2015 | archive-url =  https://web.archive.org/web/20150711154951/http://www.bloombergview.com/articles/2015-01-16/get-ready-for-life-without-oil | url-status =  live }}</ref> In the period from 2011 to 2017, progress has averaged 7.5% annually.<ref>{{Cite news|url=https://www.bloomberg.com/news/articles/2017-11-24/tesla-s-newest-promises-break-the-laws-of-batteries|title=Tesla's Newest Promises Break the Laws of Batteries|last1=Randall|first1=Tom|date=24 November 2017|work=Bloomberg.com|access-date=13 February 2018|last2=Lippert|first2=John|archive-date=12 June 2018|archive-url=https://web.archive.org/web/20180612162559/https://www.bloomberg.com/news/articles/2017-11-24/tesla-s-newest-promises-break-the-laws-of-batteries|url-status=live}}</ref>  
Overall, between 1991 and 2018, prices for all types of lithium-ion cells (in dollars per kWh) fell approximately 97%.<ref name="Ziegler-2021">{{Cite journal |last1=Ziegler |first1=Micah S. |last2=Trancik |first2=Jessika E. |date=2021-04-21 |title=Re-examining rates of lithium-ion battery technology improvement and cost decline |journal=Energy & Environmental Science |language=en |volume=14 |issue=4 |pages=1635–1651 |doi=10.1039/D0EE02681F |s2cid=220830992 |issn=1754-5706|doi-access=free |arxiv=2007.13920 |bibcode=2021EnEnS..14.1635Z }}</ref> Over the same time period, energy density more than tripled.<ref name="Ziegler-2021" />
Efforts to increase energy density contributed significantly to cost reduction.<ref>{{Cite journal |last1=Ziegler |first1=Micah S. |last2=Song |first2=Juhyun |last3=Trancik |first3=Jessika E. |date=2021-12-09 |title=Determinants of lithium-ion battery technology cost decline |journal=Energy & Environmental Science |language=en |volume=14 |issue=12 |pages=6074–6098 |doi=10.1039/D1EE01313K |s2cid=244514877 |issn=1754-5706|doi-access=free |bibcode=2021EnEnS..14.6074Z |hdl=1721.1/145588 |hdl-access=free }}</ref> Energy density can also be increased by improvements in the chemistry if the cell, for instance, by full or partial replacement of graphite with silicon. Silicon anodes enhanced with graphene nanotubes to eliminate the premature degradation of silicon open the door to reaching record-breaking battery energy density of up to 350&nbsp;Wh/kg and lowering EV prices to be competitive with ICEs.<ref>{{Cite journal |last1=Predtechenskiy |first1=Mikhail R. |last2=Khasin |first2=Alexander A. |last3=Smirnov |first3=Sergei N. |last4=Bezrodny |first4=Alexander E. |last5=Bobrenok |first5=Oleg F. |last6=Dubov |first6=Dmitry Yu. |last7=Kosolapov |first7=Andrei G. |last8=Lyamysheva |first8=Ekaterina G. |last9=Muradyan |first9=Vyacheslav E. |last10=Saik |first10=Vladimir O. |last11=Shinkarev |first11=Vasiliy V. |last12=Chebochakov |first12=Dmitriy S. |last13=Galkov |first13=Mikhail S. |last14=Karpunin |first14=Ruslan V. |last15=Verkhovod |first15=Timofey D. |date=2022-07-01 |title=New Perspectives in SWCNT Applications: Tuball SWCNTs. Part 2. New Composite Materials through Augmentation with Tuball. |journal=Carbon Trends |volume=8 |page=100176 |doi=10.1016/j.cartre.2022.100176 |issn=2667-0569|doi-access=free |bibcode=2022CarbT...800176P }}</ref>

Differently sized cells of the same format (shape) with the same chemistry may have different energy densities. [[Jelly roll (battery)|Jelly roll cell]]s usually have a higher energy density than coin or prismatic cells of the same Ah, because of a tighter/compresses packing of the cell layers. Among cylindrical cells, those with a larger size have a larger [[energy density]], albeit the exact value strongly depends on the thickness of the electrode layers. The disadvantage of large cells is decrease of the heat transfer from the cell to its surroundings.<ref name="Quinn-2018">{{cite journal |last1=Quinn |first1=Jason B. |last2=Waldmann |first2=Thomas |last3=Richter |first3=Karsten |last4=Kasper |first4=Michael |last5=Wohlfahrt-Mehrens |first5=Margret  | title = Energy Density of Cylindrical Li-Ion Cells: A Comparison of Commercial 18650 to the 21700 Cells |journal=Journal of the Electrochemical Society  | date = 19 October 2018 |volume=165 |issue=14 |pages=A3284–A3291  | doi = 10.1149/2.0281814jes |s2cid=105193083 |doi-access=free }}</ref> 

=== Round-trip efficiency ===
The table below shows the result of an experimental evaluation of a "high-energy" type 3.0&nbsp;Ah 18650 NMC cell in 2021, round-trip efficiency which compared the energy going into the cell and energy extracted from the cell from 100% (4.2v) SoC to 0% SoC (cut off 2.0v). A roundtrip efficiency is the percent of energy that can be used relative to the energy that went into charging the battery.<ref>{{Cite book |last1=Bobanac |first1=Vedran |last2=Basic |first2=Hrvoje |last3=Pandzic |first3=Hrvoje |title=IEEE EUROCON 2021 – 19th International Conference on Smart Technologies |date=2021-07-06 |chapter=Determining Lithium-ion Battery One-way Energy Efficiencies: Influence of C-rate and Coulombic Losses |chapter-url=https://animation.fer.hr/images/50036152/EUROCON%202021_Determining_Lithium-ion_Battery_One-way_Energy_Efficiencies_Influence_of_C-rate_and_Coulombic_Losses.pdf |publisher=IEEE |pages=385–389 |doi=10.1109/EUROCON52738.2021.9535542 |isbn=978-1-6654-3299-3 |s2cid=237520703 |access-date=22 June 2023 |archive-date=22 June 2023 |archive-url=https://web.archive.org/web/20230622012159/https://animation.fer.hr/images/50036152/EUROCON%202021_Determining_Lithium-ion_Battery_One-way_Energy_Efficiencies_Influence_of_C-rate_and_Coulombic_Losses.pdf |url-status=live }}</ref>
{| class="wikitable"
|+
!C rate
!efficiency
!estimated charge efficiency
!estimated discharged efficiency
|-
|0.2
|86%
|93%
|92%
|-
|0.4
|82%
|92%
|90%
|-
|0.6
|81%
|91%
|89%
|-
|0.8
|77%
|90%
|86%
|-
|1.0
|75%
|89%
|85%
|-
|1.2
|73%
|89%
|83%
|}
Characterization of a cell in a different experiment in 2017 reported round-trip efficiency of 85.5% at 2C and 97.6% at 0.1C<ref>{{Cite journal |last1=Schimpe |first1=Michael |last2=Naumann |first2=Maik |last3=Truong |first3=Nam |last4=Hesse |first4=Holger C. |last5=Santhanagopalan |first5=Shriram |last6=Saxon |first6=Aron |last7=Jossen |first7=Andreas |date=2017-11-08 |title=Energy efficiency evaluation of a stationary lithium-ion battery container storage system via electro-thermal modeling and detailed component analysis |url=https://www.osti.gov/servlets/purl/1409737 |journal=Applied Energy |language=English |volume=210 |issue=C |pages=211–229 |doi=10.1016/j.apenergy.2017.10.129 |issn=0306-2619|doi-access=free |osti=1409737 }}</ref>

== Lifespan ==
{{See also|Electronic waste|Technology-critical element}}
The lifespan of a lithium-ion battery is typically defined as the number of full charge-discharge cycles to reach a failure threshold in terms of capacity loss or impedance rise. Manufacturers' datasheets typically uses the word "cycle life" to specify lifespan in terms of the number of cycles to reach 80% of the rated battery capacity.<ref>{{Cite web | url = https://www.ineltro.ch/media/downloads/SAAItem/45/45958/36e3e7f3-2049-4adb-a2a7-79c654d92915.pdf | title = Lithium-ion Battery DATA SHEET Battery Model: LIR18650 2600&nbsp;mAh | access-date = 3 May 2019 | archive-date = 3 May 2019 | archive-url = https://web.archive.org/web/20190503022927/https://www.ineltro.ch/media/downloads/SAAItem/45/45958/36e3e7f3-2049-4adb-a2a7-79c654d92915.pdf | url-status = live }}</ref> Simply storing lithium-ion batteries in the charged state also reduces their capacity (the amount of cyclable {{chem2|Li+}}) and increases the cell resistance (primarily due to the continuous growth of the solid electrolyte interface on the anode). Calendar life is used to represent the whole life cycle of battery involving both the cycle and inactive storage operations. Battery cycle life is affected by many different stress factors including temperature, discharge current, charge current, and state of charge ranges (depth of discharge).<ref name="Wang-2011">{{Cite journal | doi = 10.1016/j.jpowsour.2010.11.134| title = Cycle-life model for graphite-LiFePO4 cells| journal = Journal of Power Sources| volume = 196| issue = 8| pages = 3942–3948| year = 2011| last1 = Wang | first1 = J.| last2 = Liu | first2 = P.| last3 = Hicks-Garner | first3 = J.| last4 = Sherman | first4 = E.| last5 = Soukiazian | first5 = S.| last6 = Verbrugge | first6 = M.| last7 = Tataria | first7 = H.| last8 = Musser | first8 = J.| last9 = Finamore | first9 = P.| bibcode = 2011JPS...196.3942W}}</ref><ref name="Saxena-2016">{{Cite journal | doi = 10.1016/j.jpowsour.2016.07.057| title = Cycle life testing and modeling of graphite/LiCoO2 cells under different state of charge ranges| journal = Journal of Power Sources| volume = 327| pages = 394–400| year = 2016| last1 = Saxena | first1 = S.| last2 = Hendricks | first2 = C.| last3 = Pecht | first3 = M.| bibcode = 2016JPS...327..394S}}</ref> Batteries are not fully charged and discharged in real applications such as smartphones, laptops and electric cars and hence defining battery life via full discharge cycles can be misleading. To avoid this confusion, researchers sometimes use cumulative discharge<ref name="Wang-2011"/> defined as the total amount of charge (Ah) delivered by the battery during its entire life or equivalent full cycles,<ref name="Saxena-2016" /> which represents the summation of the partial cycles as fractions of a full charge-discharge cycle. Battery degradation during storage is affected by temperature and battery state of charge (SOC) and a combination of full charge (100% SOC) and high temperature (usually >&nbsp;50&nbsp;°C) can result in a sharp capacity drop and gas generation.<ref>{{Cite journal | doi = 10.3390/en11123295| title = Derating Guidelines for Lithium-Ion Batteries| journal = Energies| volume = 11| issue = 12| page = 3295| year = 2018| last1 = Sun | first1 = Y.|last2 = Saxena | first2 = S.| last3 = Pecht | first3 = M.| doi-access = free| hdl = 1903/31442| hdl-access = free}}</ref> Multiplying the battery cumulative discharge by the rated nominal voltage gives the total energy delivered over the life of the battery. From this one can calculate the cost per kWh of the energy (including the cost of charging).

Over their lifespan, batteries degrade gradually leading to reduced cyclable charge (a.k.a. Ah capacity) and increased resistance (the latter translates into a lower operating cell voltage).<ref name="Hendricks-2016">{{Cite journal | doi = 10.1016/j.jpowsour.2015.07.100| title = A failure modes, mechanisms, and effects analysis (FMMEA) of lithium-ion batteries| journal = Journal of Power Sources| volume = 327| pages = 113–120| year = 2016| last1 = Hendricks | first1 = C.| last2 = Williard | first2 = N.| last3 = Mathew | first3 = S.| last4 = Pecht | first4 = M.| doi-access = free}}.</ref>

Several degradation processes occur in lithium-ion batteries, some during cycling, some during storage, and some all the time:<ref name="Voelker-2014"/><ref name="Vermeer-2022">{{Cite journal |doi=10.1109/tte.2021.3138357| title=A Comprehensive Review on the Characteristics and Modeling of Lithium-Ion Battery Aging|volume=8| issue=2| page=2205| year=2022| last1=Vermeer |first1=Wiljan| journal=IEEE Transactions on Transportation Electrification| s2cid=245463637| doi-access=free}}.</ref><ref name="Hendricks-2016"/> Degradation is strongly temperature-dependent: degradation at room temperature is minimal but increases for batteries stored or used in high temperature (usually > 35&nbsp;°C) or low temperature (usually < 5&nbsp;°C) environments.<ref name="Waldmann-2014">{{Cite journal| doi=10.1016/j.jpowsour.2014.03.112| title=Temperature dependent ageing mechanisms in Lithium-ion batteries – A Post-Mortem study| journal=Journal of Power Sources| volume=262| pages=129–135| year=2014| last1=Waldmann| first1=T.| last2=Wilka| first2=M.| last3=Kasper| first3=M.| last4=Fleischhammer| first4=M.| last5=Wohlfahrt-Mehrens| first5=M.| bibcode=2014JPS...262..129W}}</ref> Also, [[battery life]] in room temperature is maximal. High charge levels also hasten [[capacity loss]].<ref>{{cite journal |last1=Leng |first1=Feng |last2=Tan |first2=Cher Ming |last3=Pecht |first3=Michael |title=Effect of Temperature on the Aging rate of Li Ion Battery Operating above Room Temperature |journal=Scientific Reports |date=6 August 2015 |volume=5 |issue=1 |page=12967 |doi=10.1038/srep12967 |pmid=26245922 |pmc=4526891 |bibcode=2015NatSR...512967L}}</ref> Frequent charge to > 90% and discharge to < 10% may also hasten [[capacity loss]]. Keeping the li-ion battery status to about 60% to 80% can reduce the capacity loss.<ref>{{cite web | url=https://www.drrusa.com/post/optimizing-lithium-ion-battery-performance-80-20-charging-rule-and-cold-weather | title=Optimizing Lithium-ion Battery Performance: 80/20 Charging Rule and Cold Weather | date=4 December 2023 }}</ref><ref>{{cite web|url=https://forum-en.msi.com/index.php?attachments/1621510321833-png.148786/ |title=Battery Master Battery Health option|website=msi Dragon Center}}</ref>

In a study, scientists provided 3D imaging and model analysis to reveal main causes, mechanics, and potential mitigations of the problematic [[wear and tear|degradation]] of the batteries over [[charge cycle]]s. They found "[p]article cracking increases and contact loss between particles and carbon-binder domain are observed to correlate with the cell degradation" and indicates that "the reaction heterogeneity within the thick cathode caused by the unbalanced electron conduction is the main cause of the battery degradation over cycling".<ref>{{cite news |last1=Williams |first1=Sarah C. P. |title=Researchers zoom in on battery wear and tear |url=https://techxplore.com/news/2022-12-battery.html |access-date=18 January 2023 |work=[[University of Chicago]] via techxplore.com |language=en |archive-date=2 February 2023 |archive-url=https://web.archive.org/web/20230202170609/https://techxplore.com/news/2022-12-battery.html |url-status=live }}</ref><ref>{{cite journal |last1=Zhang |first1=Minghao |last2=Chouchane |first2=Mehdi |last3=Shojaee |first3=S. Ali |last4=Winiarski |first4=Bartlomiej |last5=Liu |first5=Zhao |last6=Li |first6=Letian |last7=Pelapur |first7=Rengarajan |last8=Shodiev |first8=Abbos |last9=Yao |first9=Weiliang |last10=Doux |first10=Jean-Marie |last11=Wang |first11=Shen |last12=Li |first12=Yixuan |last13=Liu |first13=Chaoyue |last14=Lemmens |first14=Herman |last15=Franco |first15=Alejandro A. |last16=Meng |first16=Ying Shirley |title=Coupling of multiscale imaging analysis and computational modeling for understanding thick cathode degradation mechanisms |journal=Joule |date=22 December 2022 |volume=7 |pages=201–220 |doi=10.1016/j.joule.2022.12.001 |language=English |issn=2542-4785 |doi-access=free }}</ref>{{additional citation needed|date=February 2023}}

The most common degradation mechanisms in lithium-ion batteries include:<ref name="Attia-2022">{{Cite journal |vauthors=Attia PM, Bills A, Planella FB, Dechent P, dos Reis G, Dubarry M, Gasper P, Gilchrist R, Greenbank S, Howey D, Liu O, Khoo E, Preger Y, Soni A, Sripad S, Stefanopoulou AG, Sulzer V |date=10 June 2022 |title=Review-"Knees" in Lithium-Ion Battery Aging Trajectories |journal=Journal of the Electrochemical Society |volume=169 |issue=6 |page=28 |doi=10.1149/1945-7111/ac6d13|arxiv=2201.02891 |bibcode=2022JElS..169f0517A |s2cid=245836782 }}.</ref>

# Reduction of the organic carbonate electrolyte at the anode, which results in the growth of [[Solid Electrolyte Interface]] (SEI), where {{chem2|Li+}} ions get irreversibly trapped, i.e. loss of lithium inventory. This shows as increased ohmic impedance of the negative electrode and a drop in the cyclable Ah charge.  At constant temperature, the SEI film thickness (and therefore, the SEI resistance and the loss in cyclable {{chem2|Li+}}) increases as a square root of the time spent in the charged state. The number of cycles is not a useful metric in characterizing this degradation pathway. Under high temperatures or in the presence of a mechanical damage the electrolyte reduction can proceed explosively.
# Lithium metal plating also results in the loss of lithium inventory (cyclable Ah charge), as well as internal short-circuiting and ignition of a battery. Once Li plating commences during cycling, it results in larger slopes of capacity loss per cycle and resistance increase per cycle. This degradation mechanism become more prominent during fast charging and low temperatures.
# Loss of the (negative or positive) electroactive materials due to dissolution (e.g. of {{chem2|Mn(3+)}} species), cracking, exfoliation, detachment or even simple regular volume change during cycling. It shows up as both charge and power fade (increased resistance). Both positive and negative electrode materials are subject to fracturing due to the volumetric strain of repeated (de)lithiation cycles.
# Structural degradation of cathode materials, such as {{chem2|Li+/Ni(2+)}} cation mixing in nickel-rich materials. This manifests as "electrode saturation", loss of cyclable Ah charge and as a "voltage fade".
# Other material degradations. Negative copper current collector is particularly prone to corrosion/dissolution at low cell voltages. PVDF binder also degrades, causing the detachment of the electroactive materials, and the loss of cyclable Ah charge.

[[File:2022-Vermeer-F2.jpg|thumb|Overview of the correlation between operational stress factors (the causes for degradation), the corresponding aging mechanisms, aging mode, and their effect on Lithium-ion batteries aging.]]
These are shown in the figure on the right. A change from one main degradation mechanism to another appears as a knee (slope change) in the capacity vs. cycle number plot.<ref name="Attia-2022"/>

Most studies of lithium-ion battery aging have been done at elevated (50–60&nbsp;°C) temperatures in order to complete the experiments sooner. Under these storage conditions, fully charged nickel-cobalt-aluminum and lithium-iron phosphate cells lose ca. 20% of their cyclable charge in 1–2 years. It is believed that the aforementioned anode aging is the most important degradation pathway in these cases.  On the other hand, manganese-based cathodes show a (ca. 20–50%) faster degradation under these conditions, probably due to the additional mechanism of Mn ion dissolution.<ref name="Vermeer-2022"/> At 25&nbsp;°C the degradation of lithium-ion batteries seems to follow the same pathway(s) as the degradation at 50&nbsp;°C, but with half the speed.<ref name="Vermeer-2022"/> In other words, based on the limited extrapolated experimental data, lithium-ion batteries are expected to lose irreversibly ca. 20% of their cyclable charge in 3–5 years or 1000–2000 cycles at 25&nbsp;°C.<ref name="Attia-2022"/> Lithium-ion batteries with titanate anodes do not suffer from SEI growth, and last longer (>5000 cycles) than graphite anodes. However, in complete cells other degradation mechanisms (i.e. the dissolution of {{chem2|Mn(3+)}} and the {{chem2|Ni(2+)/Li+}} place exchange, decomposition of PVDF binder and particle detachment) show up after 1000–2000 days, and the use titanate anode does not improve full cell durability in practice.

===Detailed degradation description===
A more detailed description of some of these mechanisms is provided below:
{{olist
|  The negative (anode) SEI layer, a passivation coating formed by electrolyte (such as [[ethylene carbonate]], [[dimethyl carbonate]] but not [[propylene carbonate]]) reduction products, is essential for providing Li<sup>+</sup> ion conduction, while preventing electron transfer (and, thus, further solvent reduction). Under typical operating conditions, the negative SEI layer reaches a fixed thickness after the first few charges (formation cycles), allowing the device to operate for years. However, at elevated temperatures or due to mechanical detachment of the negative SEI, this [[exothermic]] electrolyte reduction can proceed violently and lead to an explosion via several reactions.<ref name="Voelker-2014">{{Cite news|url = http://www.rdmag.com/articles/2014/04/trace-degradation-analysis-lithium-ion-battery-components|title = Trace Degradation Analysis of Lithium-Ion Battery Components|last = Voelker|first = Paul|date = 22 April 2014|work = R&D|access-date = 4 April 2015|archive-date = 28 April 2015|archive-url = https://web.archive.org/web/20150428160314/http://www.rdmag.com/articles/2014/04/trace-degradation-analysis-lithium-ion-battery-components|url-status = live}}</ref> Lithium-ion batteries are prone to capacity fading over hundreds<ref>{{Cite web | date = 2011-08-07 | title = How to prolong your cell phone battery's life span | url = http://www.phonedog.com/2011/8/7/how-to-prolong-your-cell-phone-battery-s-life-span|access-date=2020-07-25|website=phonedog.com}}</ref> to thousands of cycles. Formation of the SEI consumes lithium ions, reducing the overall charge and discharge efficiency of the electrode material.<ref>Alexander K Suttman.(2011).Lithium Ion Battery Aging Experiments and Algorithm Development for Life Estimation. Published by The Ohio State University and OhioLINK</ref> as a decomposition product, various SEI-forming additives can be added to the electrolyte to promote the formation of a more stable SEI that remains selective for lithium ions to pass through while blocking electrons.<ref>Matthew B. Pinson1 and Martin Z. Bazant. Theory of SEI Formation in Rechargeable Batteries: Capacity Fade, Accelerated Aging and Lifetime Prediction. Massachusetts Institute of Technology, Cambridge, MA 02139</ref>  Cycling cells at high temperature or at fast rates can promote the degradation of Li-ion batteries due in part to the degradation of the SEI or lithium plating.<ref>{{Cite web | url = https://cleantechnica.com/2019/12/16/new-data-shows-heat-fast-charging-responsible-for-more-battery-degradation-than-age-or-mileage/ | title = New Data Shows Heat & Fast-Charging Responsible For More Battery Degradation Than Age Or Mileage | date = 16 December 2019 | website = CleanTechnica | access-date = 20 December 2019 | archive-date = 27 April 2021 | archive-url = https://web.archive.org/web/20210427105747/https://cleantechnica.com/2019/12/16/new-data-shows-heat-fast-charging-responsible-for-more-battery-degradation-than-age-or-mileage/ | url-status = live }}</ref> Charging Li-ion batteries beyond 80% can drastically accelerate battery degradation.<ref>{{Cite web| url = https://www.howtogeek.com/423451/how-ios-13-will-protect-your-iphones-battery-by-charging-to-80/| title = How iOS 13 Will Save Your iPhone's Battery (by Not Fully Charging It)| website = www.howtogeek.com| date = 4 June 2019| access-date = 12 January 2020| archive-date = 7 April 2020| archive-url = https://web.archive.org/web/20200407151116/https://www.howtogeek.com/423451/how-ios-13-will-protect-your-iphones-battery-by-charging-to-80/amp/| url-status = live}}</ref><ref>{{Cite web|url=https://www.techadvisor.co.uk/how-to/mobile-phone/charge-phone-properly-3619623/|title=Battery charging tips and tricks for prolonged life|first=Simon|last=Jary|website=Tech Advisor|access-date=12 January 2020|archive-date=12 January 2020|archive-url=https://web.archive.org/web/20200112202751/https://www.techadvisor.co.uk/how-to/mobile-phone/charge-phone-properly-3619623/|url-status=live}}</ref><ref>{{Cite magazine| url = https://www.wired.co.uk/article/how-to-improve-battery-life-tips-myths-smartphones| title = Here's the truth behind the biggest (and dumbest) battery myths| first = Matt| last = Reynolds| magazine = Wired UK| date = 4 August 2018| via = www.wired.co.uk| access-date = 12 January 2020| archive-date = 12 January 2020| archive-url = https://web.archive.org/web/20200112202732/https://www.wired.co.uk/article/how-to-improve-battery-life-tips-myths-smartphones| url-status = live}}</ref><ref>{{Cite web | url = https://www.eeworldonline.com/why-you-should-stop-fully-charging-your-smartphone-now/ | title = Why You Should Stop Fully Charging Your Smartphone Now | date = 9 November 2015 | website = Electrical Engineering News and Products | access-date = 12 January 2020 | archive-date = 12 January 2020 | archive-url = https://web.archive.org/web/20200112202748/https://www.eeworldonline.com/why-you-should-stop-fully-charging-your-smartphone-now/ | url-status = live }}</ref>

Depending on the electrolyte and additives,<ref>{{Cite journal | doi = 10.1149/1945-7111/ac1e55| title = A Systematic Study of Electrolyte Additives in Single Crystal and Bimodal LiNi0.8Mn0.1 Co0.1O2/Graphite Pouch Cells| journal = Journal of the Electrochemical Society| volume = 168| issue = 9| page = 090503| year = 2021| last1 = Song | first1 = Wentao| last2 = Harlow | first2 = J.| last3 = Logan | first3 = E. | last4 = Hebecker | first4 = H.| last5 = Coon | first5 = M| last6 = Molino | first6 = L.| last7 = Johnson | first7 = M.| last8 = Dahn | first8 = J.| last9 = Metzger | first9 = M.| bibcode = 2021JElS..168i0503S| doi-access = free}}.</ref> common components of the SEI layer that forms on the anode include a mixture of lithium oxide, [[lithium fluoride]] and semicarbonates (e.g., lithium alkyl carbonates). At elevated temperatures, alkyl carbonates in the electrolyte decompose into insoluble species such as {{chem|link=Li2CO3|Li|2|CO|3}}&nbsp;that increases the film thickness. This increases cell impedance and reduces cycling capacity.<ref name="Waldmann-2014" /> Gases formed by electrolyte decomposition can increase the cell's internal pressure and are a potential safety issue in demanding environments such as mobile devices.<ref name="Voelker-2014" /> Below 25&nbsp;°C, plating of metallic Lithium on the anodes and subsequent reaction with the electrolyte is leading to loss of cyclable Lithium.<ref name="Waldmann-2014" /> Extended storage can trigger an incremental increase in film thickness and capacity loss.<ref name="Voelker-2014" /> Charging at greater than 4.2 V can initiate Li<sup>+</sup>&nbsp;plating on the anode, producing irreversible capacity loss.

Electrolyte degradation mechanisms include hydrolysis and thermal decomposition.<ref name="Voelker-2014" /> At concentrations as low as 10 ppm, water begins catalyzing a number of degradation products that can affect the electrolyte, anode and cathode.<ref name="Voelker-2014" /> {{chem|LiPF|6}} participates in an [[Chemical equilibrium|equilibrium]] reaction with LiF and {{chem|PF|5}}. Under typical conditions, the equilibrium lies far to the left. However the presence of water generates substantial LiF, an insoluble, electrically insulating product. LiF binds to the anode surface, increasing film thickness.<ref name="Voelker-2014" /> {{chem|LiPF|6}} hydrolysis yields {{chem|PF|5}}, a strong [[Lewis acid]] that reacts with electron-rich species, such as water. {{chem|PF|5}} reacts with water to form [[hydrofluoric acid]] (HF) and [[phosphorus oxyfluoride]]. Phosphorus oxyfluoride in turn reacts to form additional HF and difluorohydroxy [[phosphoric acid]]. HF converts the rigid SEI film into a fragile one. On the cathode, the carbonate solvent can then diffuse onto the cathode oxide over time, releasing heat and potentially causing thermal runaway.<ref name="Voelker-2014" /> Decomposition of electrolyte salts and interactions between the salts and solvent start at as low as 70&nbsp;°C. Significant decomposition occurs at higher temperatures. At 85&nbsp;°C [[transesterification]] products, such as dimethyl-2,5-dioxahexane carboxylate (DMDOHC) are formed from EC reacting with DMC.<ref name="Voelker-2014" />

Batteries generate heat when being charged or discharged, especially at high currents. Large battery packs, such as those used in electric vehicles, are generally equipped with thermal management systems that maintain a temperature between {{convert|15|C|F}} and {{convert|35|C|F}}.<ref>{{Cite journal|last1=Jaguemont|first1=Joris|last2=Van Mierlo|first2=Joeri|date=October 2020|title=A comprehensive review of future thermal management systems for battery-electrified vehicles|url=https://linkinghub.elsevier.com/retrieve/pii/S2352152X20301754|journal=Journal of Energy Storage|language=en|volume=31|page=101551|doi=10.1016/j.est.2020.101551|bibcode=2020JEnSt..3101551J |s2cid=219934100|access-date=28 November 2021|archive-date=24 February 2022|archive-url=https://web.archive.org/web/20220224221518/https://linkinghub.elsevier.com/retrieve/pii/S2352152X20301754|url-status=live}}</ref> Pouch and cylindrical cell temperatures depend linearly on the discharge current.<ref>{{Cite journal |doi=10.1149/2.0561506jes| title=Influence of Cell Design on Temperatures and Temperature Gradients in Lithium-Ion Cells: An in Operando Study| journal=Journal of the Electrochemical Society| volume=162| issue=6| page=A921| year=2015| last1=Waldmann| first1=T.| last2=Bisle| first2=G.| last3=Hogg| first3=B.-I.| last4=Stumpp |first4=S.| last5=Danzer |first5=M. A.| last6=Kasper| first6=M.| last7=Axmann| first7=P.| last8=Wohlfahrt-Mehrens| first8=M.| doi-access=free}}.</ref> Poor internal ventilation may increase temperatures. For large batteries consisting of multiple cells, non-uniform temperatures can lead to non-uniform and accelerated degradation.<ref>{{Cite journal |last=Malabet |first=Hernando |date=2021 |title=Electrochemical and Post-Mortem Degradation Analysis of Parallel-Connected Lithium-Ion Cells with Non-Uniform Temperature Distribution |journal=Journal of the Electrochemical Society |volume=168 |issue=10 |page=100507 |doi=10.1149/1945-7111/ac2a7c |bibcode=2021JElS..168j0507G |s2cid=244186025 |doi-access=free }}</ref> In contrast, the calendar life of [[Lithium iron phosphate battery|{{chem|LiFePO|4}}]] cells is not affected by high charge states.{{sfn|Andrea|2010|p=9}}<ref>{{Cite journal| doi=10.1016/j.jpowsour.2004.08.017| title=Modeling capacity fade in lithium-ion cells| journal=Journal of Power Sources| volume=140| issue=1| pages=157–161| year=2005| last1=Liaw| first1=B. Y.| last2=Jungst| first2=R. G.| last3=Nagasubramanian| first3=G.| last4=Case| first4=H. L.| last5=Doughty| first5=D. H.| bibcode=2005JPS...140..157L}}</ref>

Positive SEI layer in lithium-ion batteries is much less understood than the negative SEI. It is believed to have a low-ionic conductivity and shows up as an increased interfacial resistance of the cathode during cycling and calendar aging.<ref name="Voelker-2014"/><ref name="Vermeer-2022"/><ref name="Hendricks-2016"/>

| Lithium plating is a phenomenon in which certain conditions lead to metallic lithium forming and depositing onto the surface of the battery's anode rather than intercalating within the anode material's structure. Low temperatures, overcharging and high charging rates can exacerbate this occurrence.<ref>{{Cite journal |last1=Cheng |first1=Xin-Bing |last2=Zhang |first2=Rui |last3=Zhao |first3=Chen-Zi |last4=Zhang |first4=Qiang |date=2017-08-09 |title=Toward Safe Lithium Metal Anode in Rechargeable Batteries: A Review |url=https://pubs.acs.org/doi/10.1021/acs.chemrev.7b00115 |journal=Chemical Reviews |language=en |volume=117 |issue=15 |pages=10403–10473 |doi=10.1021/acs.chemrev.7b00115 |pmid=28753298 |issn=0009-2665 |access-date=5 November 2023 |archive-date=5 November 2023 |archive-url=https://web.archive.org/web/20231105034149/https://pubs.acs.org/doi/10.1021/acs.chemrev.7b00115 |url-status=live }}</ref><ref>{{Cite journal |last1=Xu |first1=Wu |last2=Wang |first2=Jiulin |last3=Ding |first3=Fei |last4=Chen |first4=Xilin |last5=Nasybulin |first5=Eduard |last6=Zhang |first6=Yaohui |last7=Zhang |first7=Ji-Guang |date=2014-01-23 |title=Lithium metal anodes for rechargeable batteries |url=https://pubs.rsc.org/en/content/articlelanding/2014/ee/c3ee40795k |journal=Energy & Environmental Science |language=en |volume=7 |issue=2 |pages=513–537 |doi=10.1039/C3EE40795K |bibcode=2014EnEnS...7..513X |issn=1754-5706 |access-date=5 November 2023 |archive-date=5 November 2023 |archive-url=https://web.archive.org/web/20231105034150/https://pubs.rsc.org/en/content/articlelanding/2014/ee/c3ee40795k |url-status=live }}</ref> During these conditions, lithium ions may not intercalate uniformly into the anode material and form layers of lithium ion on the surface in the form of [[Dendrite (crystal)|dendrites]]. Dendrites are tiny needle-like structures that can accumulate and pierce the separator, causing a [[short circuit]] can initiate [[thermal runaway]].<ref name="Voelker-2014" />  This cascade of rapid and uncontrolled energy can lead to battery swelling, increased heat, fires and or explosions.<ref>{{Cite journal |last1=Lyu |first1=Peizhao |last2=Liu |first2=Xinjian |last3=Qu |first3=Jie |last4=Zhao |first4=Jiateng |last5=Huo |first5=Yutao |last6=Qu |first6=Zhiguo |last7=Rao |first7=Zhonghao |date=2020-10-01 |title=Recent advances of thermal safety of lithium ion battery for energy storage |url=https://www.sciencedirect.com/science/article/pii/S2405829720302646 |journal=Energy Storage Materials |volume=31 |pages=195–220 |doi=10.1016/j.ensm.2020.06.042 |bibcode=2020EneSM..31..195L |s2cid=225545635 |issn=2405-8297}}</ref> Additionally, this dendritic growth can lead to side reactions with the electrolyte and convert the fresh plated lithium into electrochemically inert dead lithium.<ref name="Besenhard-1974" /> Moreover, the dendritic growth brought on by lithium plating can degrade the lithium-ion battery and lead to poor cycling efficiency and safety hazards. Some ways to mitigate lithium plating and the dendritic growth is by controlling the temperature, optimizing the charging conditions, and improving the materials used.<ref>{{Cite journal |last1=Lei |first1=Yanxiang |last2=Zhang |first2=Caiping |last3=Gao |first3=Yang |last4=Li |first4=Tong |date=2018-10-01 |title=Charging Optimization of Lithium-ion Batteries Based on Capacity Degradation Speed and Energy Loss |journal=Energy Procedia |series=Cleaner Energy for Cleaner Cities |volume=152 |pages=544–549 |doi=10.1016/j.egypro.2018.09.208 |s2cid=115875535 |issn=1876-6102|doi-access=free |bibcode=2018EnPro.152..544L }}</ref> In terms of temperature, the ideal charging temperature is anywhere between 0&nbsp;°C to 45&nbsp;°C, but also room temperature is ideal (20&nbsp;°C to 25&nbsp;°C).<ref>{{Cite journal |last1=Bandhauer |first1=Todd M. |last2=Garimella |first2=Srinivas |author2-link=Srinivas Garimella |last3=Fuller |first3=Thomas F. |date=2011-01-25 |title=A Critical Review of Thermal Issues in Lithium-Ion Batteries |journal=Journal of the Electrochemical Society |language=en |volume=158 |issue=3 |pages=R1 |doi=10.1149/1.3515880 |s2cid=97367770 |issn=1945-7111|doi-access=free }}</ref> Advancements in materials innovation requires much [[Research in lithium-ion batteries|research and development]] in the electrolyte selection and improving the anode resistance to plating. One such materials innovation would be to add other compounds to the electrolyte like fluoroethylene carbonate (FEC) to form a rich LiF SEI.<ref>{{Cite journal |last1=Zhang |first1=Xue-Qiang |last2=Cheng |first2=Xin-Bing |last3=Chen |first3=Xiang |last4=Yan |first4=Chong |last5=Zhang |first5=Qiang |date=March 2017 |title=Fluoroethylene Carbonate Additives to Render Uniform Li Deposits in Lithium Metal Batteries |url=https://onlinelibrary.wiley.com/doi/10.1002/adfm.201605989 |journal=Advanced Functional Materials |language=en |volume=27 |issue=10 |doi=10.1002/adfm.201605989 |s2cid=99575315 |issn=1616-301X |access-date=5 November 2023 |archive-date=5 November 2023 |archive-url=https://web.archive.org/web/20231105034150/https://onlinelibrary.wiley.com/doi/10.1002/adfm.201605989 |url-status=live }}</ref>  Another novel method would be to coat the separator in a protective shield that essentially "kills" the lithium ions before it can form these dendrites.<ref>{{Cite journal |last1=Zhang |first1=Sheng S. |last2=Fan |first2=Xiulin |last3=Wang |first3=Chunsheng |date=2018-06-12 |title=Preventing lithium dendrite-related electrical shorting in rechargeable batteries by coating separator with a Li-killing additive |url=https://pubs.rsc.org/en/content/articlelanding/2018/ta/c8ta02804d |journal=Journal of Materials Chemistry A |language=en |volume=6 |issue=23 |pages=10755–10760 |doi=10.1039/C8TA02804D |issn=2050-7496 |access-date=5 November 2023 |archive-date=5 November 2023 |archive-url=https://web.archive.org/web/20231105034150/https://pubs.rsc.org/en/content/articlelanding/2018/ta/c8ta02804d |url-status=live }}</ref>

| Certain manganese containing cathodes can degrade by the Hunter degradation mechanism resulting in manganese dissolution and reduction on the anode.<ref name="Voelker-2014" /> By the Hunter mechanism for {{chem|LiMn|2|O|4}}, hydrofluoric acid catalyzes the loss of manganese through disproportionation of a surface trivalent manganese to form a tetravalent manganese and a soluble divalent manganese:<ref name="Voelker-2014" />

: 2Mn<sup>3+</sup> → Mn<sup>2+</sup>+ Mn<sup>4+</sup>

Material loss of the spinel results in capacity fade. Temperatures as low as 50&nbsp;°C initiate Mn<sup>2+ </sup>deposition on the anode as metallic manganese with the same effects as lithium and copper plating.<ref name="Waldmann-2014" /> Cycling over the theoretical max and min voltage plateaus destroys the [[crystal lattice]] via [[Jahn-Teller distortion]], which occurs when Mn<sup>4+</sup> is reduced to Mn<sup>3+</sup> during discharge.<ref name="Voelker-2014" /> Storage of a battery charged to greater than 3.6 V initiates electrolyte oxidation by the cathode and induces SEI layer formation on the cathode. As with the anode, excessive SEI formation forms an insulator resulting in capacity fade and uneven current distribution.<ref name="Voelker-2014" /> Storage at less than 2 V results in the slow degradation of {{chem|LiCoO|2}} and {{chem|LiMn|2|O|4}} cathodes, the release of oxygen and irreversible capacity loss.<ref name="Voelker-2014" />

| Cation mixing is the main reason for the capacity decline of the Ni-rich cathode materials. As the Ni content in the NCM layered material increases the capacity will increase, which is the result of two-electron of Ni<sup>2+</sup>/Ni<sup>4+</sup> redox reaction (please note, that Mn remains electrochemically inactive in the 4+ state) but, increasing the Ni content results in a significant degree of mixing of Ni<sup>2+</sup> and Li<sup>+</sup> cations due to the closeness of their ionic radius (Li<sup>+</sup> =0.076&nbsp;nm and Ni<sup>2+</sup> =0.069&nbsp;nm). During charge/discharge cycling, the Li<sup>+</sup> in the cathode cannot be easily be extracted and the existence of Ni<sup>2+</sup> in the Li layer blocks the diffusion of Li<sup>+</sup>, resulting in both capacity loss and increased ohmic resistance.<ref>{{Cite journal |vauthors=Geldasa FT, Kebede MA, Shura MW, Hone FG |date=2022 |title=Identifying surface degradation, mechanical failure, and thermal instability phenomena of high energy density Ni-rich NCM cathode materials for lithium-ion batteries: a review |journal=RSC Advances |volume=12 |issue=10 |pages=5891–5909 |doi=10.1039/d1ra08401a|pmid=35424548 |pmc=8982025 |bibcode=2022RSCAd..12.5891G }}</ref>

| Discharging below {{val|2|u=V}} can also result in the dissolution of the copper anode current collector and, thus, in catastrophic internal short-circuiting on recharge.
}}

===Recommendations===
The [[IEEE]] standard 1188–1996 recommends replacing lithium-ion batteries in an electric vehicle, when their charge capacity drops to 80% of the nominal value.<ref>{{Cite journal |vauthors=Pang XX, Zhong S, Wang YL, Yang W, Zheng WZ, Sun GZ |date=2022 |title=A Review on the Prediction of Health State and Serving Life of Lithium-Ion Batteries |journal=Chemical Record |volume=22 |issue=10 |pages=e202200131 |doi=10.1002/tcr.202200131|pmid=35785467 |s2cid=250282891 }}</ref> In what follows, we shall use the 20% capacity loss as a comparison point between different studies. We shall note, nevertheless, that the linear model of degradation (the constant % of charge loss per cycle or per calendar time) is not always applicable, and that a "knee point", observed as a change of the slope, and related to the change of the main degradation mechanism, is often observed.<ref>{{Cite journal |vauthors=Li AG, West AC, Preindl M |date=2022 |title=Towards unified machine learning characterization of lithium-ion battery degradation across multiple levels: A critical review |journal=Applied Energy |volume=316 |page=9|doi=10.1016/j.apenergy.2022.119030 |bibcode=2022ApEn..31619030L |s2cid=246554618 }}</ref>

== Safety ==
The problem of lithium-ion battery safety was recognized even before these batteries were first commercially released in 1991. The two main reasons for lithium-ion battery fires and explosions are related to processes on the negative electrode (cathode). During a normal battery charge lithium ions intercalate into graphite. However, if the charge is forced to go too fast (or at a too low temperature) lithium metal starts plating on the anode, and the resulting dendrites can penetrate the battery separator, internally short-circuit the cell, and result in high electric current, heating and ignition. In other mechanisms, an explosive reaction between the charge anode material (LiC<sub>6</sub>) and the solvent (liquid organic carbonate) occurs even at open circuit, provided that the anode temperature exceeds a certain threshold above 70&nbsp;°C.<ref>{{cite journal | doi=10.1149/2.1051816jes | title=On the Decomposition of Carbonate-Based Lithium-Ion Battery Electrolytes Studied Using Operando Infrared Spectroscopy | date=2018 | last1=Saqib | first1=Najmus | last2=Ganim | first2=Chase M. | last3=Shelton | first3=Austin E. | last4=Porter | first4=Jason M. | journal=Journal of the Electrochemical Society | volume=165 | issue=16 | pages=A4051–A4057 | doi-access=free }}</ref>

Nowadays, all reputable manufacturers employ at least two safety devices in all their lithium-ion batteries of an 18650 format or larger: a current interrupt (CID)  device and a positive temperature coefficient (PTC) device. The CID comprises two metal disks that make an electric contact with each other. When pressure inside the cell increases, the distance between the two disks increases too and they lose the electric contact with each other, thus terminating the electric current through the battery. The PTC device is made of an electrically conducting polymer. When the current through the PTC device increases, the polymer gets hot, and its electric resistance rises sharply, thus reducing the current through the battery.<ref>{{cite journal | doi=10.1021/acsenergylett.3c00724 | title=Safety and Quality Issues of Counterfeit Lithium-Ion Cells | date=2023 | last1=Joshi | first1=Tapesh | last2=Azam | first2=Saad | last3=Juarez-Robles | first3=Daniel | last4=Jeevarajan | first4=Judith A. | journal=ACS Energy Letters | volume=8 | issue=6 | pages=2831–2839 | pmid=37324540 | pmc=10262263 }}</ref>

=== Fire hazard ===
{{See also|Plug-in electric vehicle fire incidents}}

Lithium-ion batteries can be a safety hazard since they contain a flammable electrolyte and may become pressurized if they become damaged. A battery cell charged too quickly could cause a [[short circuit]], leading to overheating, explosions, and fires.<ref name="Hislop-2017">{{cite web |url=http://theamericanenergynews.com/markham-on-energy/solid-state-battery-advance-goodenough |title=Solid-state EV battery breakthrough from Li-ion battery inventor John Goodenough |last=Hislop |first=Martin |date=1 March 2017 |website=North American Energy News |publisher=The American Energy News. |access-date=15 March 2017 |archive-date=12 November 2020 |archive-url=https://web.archive.org/web/20201112024323/http://theamericanenergynews.com/markham-on-energy/solid-state-battery-advance-goodenough |url-status=live }}</ref> A Li-ion battery fire can be started due to
# thermal abuse, e.g. poor cooling or external fire,
# electrical abuse, e.g. overcharge or external short circuit,
# mechanical abuse, e.g. penetration or crash, or
# internal short circuit, e.g. due to manufacturing flaws or aging.<ref>{{Cite journal|last1=Bisschop|first1=Roeland |last2=Willstrand|first2=Ola |last3=Rosengren|first3=Max |date=2020-11-01|title=Handling Lithium-Ion Batteries in Electric Vehicles: Preventing and Recovering from Hazardous Events|journal=Fire Technology|language=en|volume=56|issue=6 |pages=2671–2694 |doi=10.1007/s10694-020-01038-1|s2cid=225315970|issn=1572-8099|doi-access=free}}</ref><ref>{{Cite book|last1=Bisschop|first1=Roeland |url=http://urn.kb.se/resolve?urn=urn:nbn:se:ri:diva-38873 |title=Fire Safety of Lithium-Ion Batteries in Road Vehicles|last2=Willstrand|first2=Ola |last3=Amon|first3=Francine |last4=Rosenggren|first4=Max |date=2019|publisher=RISE Research Institutes of Sweden|isbn=978-91-88907-78-3|access-date=5 October 2021|archive-date=11 January 2024|archive-url= https://web.archive.org/web/20240111000253/https://ri.diva-portal.org/smash/record.jsf?pid=diva2%3A1317419&dswid=-6105 |url-status=live}}</ref>
Because of these risks, testing standards are more stringent than those for acid-electrolyte batteries, requiring both a broader range of test conditions and additional battery-specific tests, and there are shipping limitations imposed by safety regulators.<ref name="Schweber-2015">{{cite web |url=http://electronics360.globalspec.com/article/5555/lithium-batteries-the-pros-and-cons |title=Lithium Batteries: The Pros and Cons |last=Schweber |first=Bill |date=4 August 2015 |website=GlobalSpec |access-date=15 March 2017 |archive-date=16 March 2017 |archive-url= https://web.archive.org/web/20170316024534/http://electronics360.globalspec.com/article/5555/lithium-batteries-the-pros-and-cons |url-status=live }}</ref><ref>Millsaps, C. (10 July 2012). [http://www.batterypoweronline.com/main/markets/manufacturing-materials/second-edition-of-iec-62133-the-standard-for-secondary-cells-and-batteries-containing-alkaline-or-other-non-acid-electrolytes-is-in-its-final-review-cycle/ Second Edition of IEC 62133: The Standard for Secondary Cells and Batteries Containing Alkaline or Other Non-Acid Electrolytes is in its Final Review Cycle] {{Webarchive|url= https://web.archive.org/web/20140110182139/http://www.batterypoweronline.com/main/markets/manufacturing-materials/second-edition-of-iec-62133-the-standard-for-secondary-cells-and-batteries-containing-alkaline-or-other-non-acid-electrolytes-is-in-its-final-review-cycle/ |date=10 January 2014 }}. Retrieved from Battery Power Online (10 January 2014)</ref><ref name="IEC-2012">{{cite book | title = IEC 62133. Secondary cells and batteries containing alkaline or other non-acid electrolytes – Safety requirements for portable sealed secondary cells, and for batteries made from them, for use in portable applications |publisher=International Electrotechnical Commission | date = December 2012 |edition=2.0 |isbn=978-2-83220-505-1}}</ref> There have been battery-related recalls by some companies, including the 2016 [[Samsung]] [[Samsung Galaxy Note 7#Battery faults|Galaxy Note 7 recall]] for battery fires.<ref name="Kwon-2016">{{Cite web|url=https://money.cnn.com/2016/09/02/technology/samsung-galaxy-note-7-recall/index.html |title=Samsung is recalling the Galaxy Note 7 worldwide over battery problem|last=Kwon|first=Jethro Mullen and K. J.|date=2 September 2016|website=CNNMoney|access-date=13 September 2019|archive-date=17 June 2019|archive-url= https://web.archive.org/web/20190617140048/https://money.cnn.com/2016/09/02/technology/samsung-galaxy-note-7-recall/index.html |url-status=live}}</ref><ref name="newscomau-2016">{{Cite web |date=2 September 2016 |title=Samsung recall for Galaxy Note 7 |url=http://www.news.com.au/finance/business/breaking-news/samsung-to-recall-phones-after-explosions/news-story/3ef0b353b48e94477a75e2f08cbb2312 |archive-url= https://web.archive.org/web/20160902090545/http://www.news.com.au/finance/business/breaking-news/samsung-to-recall-phones-after-explosions/news-story/3ef0b353b48e94477a75e2f08cbb2312 |archive-date=2 September 2016 |work=news.com.au}}</ref>

Lithium-ion batteries have a flammable liquid electrolyte.<ref name="Kanellos-2006">{{cite web| title = Can anything tame the battery flames?| url = http://news.cnet.com/Can-anything-tame-the-battery-flames/2100-11398_3-6105924.html| publisher = CNET| author = Kanellos, Michael| date = 15 August 2006| access-date = 14 June 2013| archive-date = 9 December 2013| archive-url = https://web.archive.org/web/20131209210515/http://news.cnet.com/Can-anything-tame-the-battery-flames/2100-11398_3-6105924.html| url-status = live}}</ref> A faulty battery can cause a serious [[Conflagration|fire]].<ref name="Hislop-2017"/> Faulty chargers can affect the safety of the battery because they can destroy the battery's protection circuit. While charging at temperatures below 0&nbsp;°C, the negative electrode of the cells gets plated with pure lithium, which can compromise the safety of the whole pack.

[[Short circuit|Short-circuiting]] a battery will cause the cell to overheat and possibly to catch fire.<ref name="Electrochem-2006">{{cite web | title = Safety and handling guidelines for Electrochem Lithium Batteries | date = 9 September 2006 | author = Electrochem Commercial Power | publisher = Rutgers University | url = http://marine.rutgers.edu/~haldeman/Instruments/lithium_safety/Electrochem_Lithium_safety_15-SAF-0043.pdf | access-date = 21 May 2009 | archive-date = 20 July 2011 | archive-url = https://web.archive.org/web/20110720041137/http://marine.rutgers.edu/~haldeman/Instruments/lithium_safety/Electrochem_Lithium_safety_15-SAF-0043.pdf | url-status = live }}</ref> Smoke from thermal runaway in a Li-ion battery is both flammable and toxic.<ref>{{Cite book|last1=Willstrand|first1=Ola |url=http://urn.kb.se/resolve?urn=urn:nbn:se:ri:diva-52000 |title=Toxic Gases from Fire in Electric Vehicles|last2=Bisschop|first2=Roeland |last3=Blomqvist|first3=Per |last4=Temple|first4=Alastair |last5=Anderson|first5=Johan |date=2020|publisher=RISE Research Institutes of Sweden|isbn=978-91-89167-75-9|access-date=5 October 2021|archive-date=11 January 2024|archive-url=https://web.archive.org/web/20240111000252/https://ri.diva-portal.org/smash/record.jsf?pid=diva2%3A1522149&dswid=2413 |url-status=live}}</ref> Batteries are tested according to the UL 9540A fire standard, and the TS-800 standard also tests fire propagation from one battery container to adjacent containers.<ref>{{cite web |last1=Rayner |first1=Tristan |title=Battery storage providers highlight fire test results as industry continues focus on safety |url=https://www.ess-news.com/2025/04/25/battery-storage-providers-highlight-fire-test-results-as-industry-continues-focus-on-safety/ |website=Energy Storage |date=25 April 2025}}</ref>

Around 2010, large lithium-ion batteries were introduced in place of other chemistries to power systems on some aircraft; {{As of|2014|1|lc=on}}, there had been at least four serious [[Boeing 787 Dreamliner battery problems|lithium-ion battery fires, or smoke, on the Boeing 787]] passenger aircraft, introduced in 2011, which did not cause crashes but had the potential to do so.<ref>Topham, Gwyn (18 July 2013). [https://www.theguardian.com/world/2013/jul/18/heathrow-fire-boeing-dreamliner-battery "Heathrow fire on Boeing Dreamliner 'started in battery component'"] {{Webarchive|url=https://web.archive.org/web/20170222140351/https://www.theguardian.com/world/2013/jul/18/heathrow-fire-boeing-dreamliner-battery |date=22 February 2017 }}. ''The Guardian''.</ref><ref>{{Cite news  | url = https://www.bbc.co.uk/news/business-25737515  | title = Boeing 787 aircraft grounded after battery problem in Japan  | journal = BBC News  | date = 14 January 2014  | access-date = 16 January 2014  | archive-date = 16 January 2014  | archive-url = https://web.archive.org/web/20140116062625/http://www.bbc.co.uk/news/business-25737515  | url-status = live  }}</ref> [[UPS Airlines Flight 6]] crashed in [[Dubai]] after its payload of batteries spontaneously ignited.

To reduce fire hazards, research projects are intended to develop non-flammable electrolytes.<ref>{{Cite web |last=University |first=Doshisha |date=2025-01-13 |title=Novel Battery Design Could Make Electric Vehicles Safer, More Reliable |url=https://scienceblog.com/novel-battery-design-could-make-electric-vehicles-safer-more-reliable/ |access-date=2025-04-29 |website=ScienceBlog.com |language=en-US}}</ref>

=== Damaging and overloading ===
If a lithium-ion battery is damaged, crushed, or subjected to a higher electrical load without having overcharge protection, problems may arise. External short circuit can trigger a battery explosion.<ref>{{Cite journal|last1=Chen|first1=Mingyi|last2=Liu|first2=Jiahao|last3=He|first3=Yaping|last4=Yuen|first4=Richard|last5=Wang|first5=Jian | date = October 2017 | title = Study of the fire hazards of lithium-ion batteries at different pressures|journal=Applied Thermal Engineering|volume=125|pages=1061–1074 | doi = 10.1016/j.applthermaleng.2017.06.131|bibcode=2017AppTE.125.1061C |issn=1359-4311}}</ref>
Such incidents can occur when lithium-ion batteries are not disposed of through the appropriate channels, but are thrown away with other waste. The way they are treated by recycling companies can damage them and cause fires, which in turn can lead to large-scale conflagrations. Twelve such fires were recorded in Swiss recycling facilities in 2023.<ref>
{{cite news|author=[[Pierre Cormon]]| url = https://www.entrepriseromande.ch/web/er/w/batteries-lithium-ion-un-grave-danger-pour-les-recycleurs | title = Les batteries lithium-ion, un grave danger pour les recycleurs | last1 = | first1 = | publisher = [[Fédération des Entreprises Romandes Genève]] | newspaper = Entreprise romande | date = 20 June 2024 | access-date =  30 June 2024}}</ref>

If overheated or overcharged, Li-ion batteries may suffer [[thermal runaway]] and cell rupture.<ref name="Spotnitz-2003">{{Cite journal | last1 = Spotnitz | first1 = R. | last2 = Franklin | first2 = J. | doi = 10.1016/S0378-7753(02)00488-3 | title = Abuse behavior of high-power, lithium-ion cells | journal = Journal of Power Sources | volume = 113 | issue = 1 | pages = 81–100 | year = 2003 | bibcode = 2003JPS...113...81S }}</ref><ref name="Finegan-2015">{{Cite journal | doi = 10.1038/ncomms7924| title = In-operando high-speed tomography of lithium-ion batteries during thermal runaway| journal = Nature Communications| volume = 6| page = 6924| year = 2015| last1 = Finegan | first1 = D. P. | last2 = Scheel | first2 = M. | last3 = Robinson | first3 = J. B. | last4 = Tjaden | first4 = B. | last5 = Hunt | first5 = I. | last6 = Mason | first6 = T. J. | last7 = Millichamp | first7 = J. | last8 = Di Michiel | first8 = M. | last9 = Offer | first9 = G. J. | last10 = Hinds | first10 = G. | last11 = Brett | first11 = D. J. L. | last12 = Shearing | first12 = P. R. | pmid=25919582 | pmc=4423228| bibcode = 2015NatCo...6.6924F }}</ref> During thermal runaway, internal degradation and [[Oxidisation|oxidization]] processes can keep cell temperatures above 500&nbsp;°C, with the possibility of igniting secondary combustibles, as well as leading to leakage, explosion or fire in extreme cases.<ref>{{Cite book |last1=Loznen |first1=Steli |title=Electrical product compliance and safety engineering |last2=Bolintineanu |first2=Constantin |last3=Swart |first3=Jan |publisher=Artech House |year=2017 |isbn=978-1-63081-011-5 |location=Boston |pages=192–196}}</ref> To reduce these risks, many lithium-ion cells (and battery packs) contain fail-safe circuitry that disconnects the battery when its voltage is outside the safe range of 3–4.2&nbsp;V per cell,<ref name="GoldPeak-2003">{{Cite book |url=http://www.gpina.com/pdf/Li-ion_Handbook.pdf |title=Lithium Ion technical handbook |date=November 2003 |publisher=Gold Peak Industries Ltd. |archive-url=https://web.archive.org/web/20071007175038/http://www.gpbatteries.com/html/pdf/Li-ion_handbook.pdf |archive-date=7 October 2007}}</ref><ref name="Winter-2004a">{{harvnb|Winter|Brodd|2004|p=4259}}</ref> or when overcharged or discharged. Lithium battery packs, whether constructed by a vendor or the end-user, without effective battery management circuits are susceptible to these issues. Poorly designed or implemented battery management circuits also may cause problems; it is difficult to be certain that any particular battery management circuitry is properly implemented.

=== Voltage limits ===
Lithium-ion cells are susceptible to stress by voltage ranges outside of safe ones between 2.5 and 3.65/4.1/4.2 or 4.35&nbsp;V (depending on the components of the cell). Exceeding this voltage range results in premature aging and in safety risks due to the reactive components in the cells.<ref name="Väyrynen-2012">{{Cite journal | doi = 10.1016/j.jct.2011.09.005| title = Lithium ion battery production| journal = The Journal of Chemical Thermodynamics| volume = 46| pages = 80–85| year = 2012| last1 = Väyrynen | first1 = A. | last2 = Salminen | first2 = J. | bibcode = 2012JChTh..46...80V}}</ref> When stored for long periods the small current draw of the protection circuitry may drain the battery below its shutoff voltage; normal chargers may then be useless since the [[battery management system]] (BMS) may retain a record of this battery (or charger) "failure". Many types of lithium-ion cells cannot be charged safely below 0&nbsp;°C,<ref>{{cite web|title=Lithium-ion Battery Charging Basics|url=http://www.powerstream.com/li.htm|publisher=PowerStream Technologies|access-date=4 December 2010|archive-date=28 April 2021|archive-url=https://web.archive.org/web/20210428214636/http://www.powerstream.com/li.htm|url-status=live}}</ref> as this can result in plating of lithium on the anode of the cell, which may cause complications such as internal short-circuit paths.<ref>{{Cite web |last=UCSB EH&S |date=2021-09-01 |title=Lithium-ion Battery Fire |url=https://www.ehs.ucsb.edu/sites/default/files/docs/ls/Lithium%20Battery%20Safety%20Checklist.pdf |access-date=2025-05-28 |website=Environmental Health & Safety, University of California, Santa Barbara |quote=Temperatures below freezing at 32°F during charging can lead to metallic lithium plating on the anode (lithium metal buildup), increasing the risk of short circuits and increased internal heat of the battery.}}</ref>

Other safety features are required{{by whom | date = July 2020}} in each cell:<ref name="GoldPeak-2003"/>
* Shut-down separator (for overheating)
* Tear-away tab (for internal pressure relief)
* Vent (pressure relief in case of severe outgassing)
* Thermal interrupt (overcurrent/overcharging/environmental exposure)

These features are required because the negative electrode produces heat during use, while the positive electrode may produce oxygen. However, these additional devices occupy space inside the cells, add points of failure, and may irreversibly disable the cell when activated. Further, these features increase costs compared to [[Nickel–metal hydride battery|nickel metal hydride batteries]], which require only a hydrogen/oxygen recombination device and a back-up pressure valve.<ref name="Winter-2004a"/> Contaminants inside the cells can defeat these safety devices. Also, these features can not be applied to all kinds of cells, e.g., prismatic high-current cells cannot be equipped with a vent or thermal interrupt. High-current cells must not produce excessive heat or oxygen, lest there be a failure, possibly violent. Instead, they must be equipped with internal thermal fuses which act before the anode and cathode reach their thermal limits.<ref>{{cite journal |last1=Liu |first1=Xingjiang |last2=Kusawake |first2=Hiroaki |last3=Kuwajima |first3=Saburo |title=Preparation of a PVdF-HFP/polyethylene composite gel electrolyte with shutdown function for lithium-ion secondary battery |journal=Journal of Power Sources |date=July 2001 |volume=97–98 |pages=661–663 |doi=10.1016/S0378-7753(01)00583-3|bibcode=2001JPS....97..661L }}</ref>

Replacing the [[lithium cobalt oxide]] positive electrode material in lithium-ion batteries with a lithium metal phosphate such as lithium iron phosphate (LFP) improves cycle counts, shelf life and safety, but lowers capacity. As of 2006, these safer lithium-ion batteries were mainly used in [[electric car]]s and other large-capacity battery applications, where safety is critical.<ref>{{Cite news | url=https://www.nytimes.com/2006/09/01/opinion/01cringely.html | work=The New York Times | title=Safety Last | first=Robert X. | last=Cringely | date=1 September 2006 | access-date=14 April 2010 | archive-date=4 July 2012 | archive-url=https://web.archive.org/web/20120704053530/http://www.nytimes.com/2006/09/01/opinion/01cringely.html? | url-status=live }}</ref> In 2016, an LFP-based energy storage system was chosen to be installed in [[Paiyun Lodge]] on [[Yu Shan|Mt.Jade (Yushan)]] (the highest lodge in [[Taiwan]]). As of June 2024, the system was still operating safely.<ref name="Chung-2024">{{cite journal |last1=Chung |first1=Hsien-Ching |title=The Long-Term Usage of an Off-Grid Photovoltaic System with a Lithium-Ion Battery-Based Energy Storage System on High Mountains: A Case Study in Paiyun Lodge on Mt. Jade in Taiwan |journal=Batteries |date=13 June 2024 |volume=10 |issue=6 |page=202 |doi=10.3390/batteries10060202|doi-access=free |arxiv=2405.04225 }}</ref>

=== Recalls ===
In 2006, approximately 10 million Sony batteries used in laptops were recalled, including those in laptops from [[Dell]], [[Sony]], [[Apple Inc.|Apple]], [[Lenovo]], [[Panasonic]], [[Toshiba]], [[Hitachi, Ltd.|Hitachi]], [[Fujitsu]] and [[Sharp Corporation|Sharp]]. The batteries were found to be susceptible to internal contamination by metal particles during manufacture. Under some circumstances, these particles could pierce the separator, causing a dangerous short circuit.<ref>Hales, Paul (21 June 2006). [https://web.archive.org/web/20070905234726/http://www.theinquirer.net/default.aspx?article=32550 Dell laptop explodes at Japanese conference]. ''[[The Inquirer]]''. Retrieved 15 June 2010.</ref>

[[File:1-7-12 JAL787 APU Battery.JPG|thumb|Japan Airlines Boeing 787 lithium cobalt oxide battery [[Boeing 787 Dreamliner battery problems|that caught fire in 2013]]]]
[[File:ADR 9A.svg|thumb|upright|Transport Class 9A:Lithium batteries]]

[[International Air Transport Association|IATA]] estimates that over a billion [[lithium metal battery|lithium metal]] and lithium-ion cells are flown each year.<ref name="Mikolajczak-2011">{{cite web|author1=Mikolajczak, Celina|author1-link= Celina Mikolajczak |author2=Kahn, Michael |author3=White, Kevin |author4=Long, Richard Thomas |name-list-style=amp | title = Lithium-Ion Batteries Hazard and Use Assessment  | url = http://www.nfpa.org/assets/files//PDF/Research/RFLithiumIonBatteriesHazard.pdf |publisher=Fire Protection Research Foundation |pages=76, 90, 102 |access-date=27 January 2013  | date = July 2011 |archive-url=https://web.archive.org/web/20130513081920/http://www.nfpa.org/assets/files//PDF/Research/RFLithiumIonBatteriesHazard.pdf |archive-date=13 May 2013 }}</ref> Some kinds of lithium batteries may be prohibited aboard aircraft because of the fire hazard.<ref>{{Cite book|isbn = 978-0-306-44758-7|pages = 15–16|url = https://books.google.com/books?id=i7U-0IB8tjMC&pg=PA15|author = Bro, Per|author2 = Levy, Samuel C.|name-list-style = amp|date = 1994|publisher = Plenum Press|location = New York|title = Battery hazards and accident prevention|access-date = 29 December 2020|archive-date = 11 January 2024|archive-url = https://web.archive.org/web/20240111000132/https://books.google.com/books?id=i7U-0IB8tjMC&pg=PA15#v=onepage&q&f=false|url-status = live}}</ref><ref>{{cite web | url = http://www.tsa.gov/travelers/airtravel/assistant/batteries.shtm |archive-url=https://web.archive.org/web/20120104141539/http://www.tsa.gov/travelers/airtravel/assistant/batteries.shtm |archive-date=4 January 2012  | title = TSA: Safe Travel with Batteries and Devices |publisher=Tsa.gov  | date = 1 January 2008}}</ref> Some postal administrations restrict air shipping (including [[Express Mail Service|EMS]]) of lithium and lithium-ion batteries, either separately or installed in equipment.

=== Non-flammable electrolyte ===
In 2023, most commercial Li-ion batteries employed [[alkylcarbonate]] solvent(s) to assure the formation [[solid electrolyte interface]] on the negative electrode. Since such solvents are readily flammable, there has been active research to replace them with non-flammable solvents or to add [[fire suppressants]]. Another source of hazard is [[hexafluorophosphate]] anion, which is needed to passivate the negative current collector made of [[aluminium]]. Hexafluorophosphate reacts with water and releases volatile and toxic [[hydrogen fluoride]]. Efforts to replace hexafluorophosphate have been less successful.

== Supply chain ==
{{Excerpt|Lithium-ion battery supply chain}}

Li-ion battery production is heavily concentrated, with 60% coming from [[China]] in 2024.<ref>Restrepo N, Uribe JM, Guillen M. Price bubbles in lithium markets around the world. Front Energy Res. 2023;11:11  doi:  10.3389/fenrg.2023.1204179.</ref>

In the 1990s, the United States was the World's largest miner of lithium minerals, contributing to 1/3 of the total production. By 2010 [[Chile]] replaced the USA the leading miner, thanks to the development of lithium brines in [[Salar de Atacama]]. By 2024, [[Australia]] and China joined Chile as the top 3 miners.

=== Environmental impact ===
{{Further|Environmental impacts of lithium-ion batteries}}{{See also|Lithium#Environmental issues}}
[[File:Geographical distribution of the global battery supply chain.png|thumb|270px|Geographical distribution of the [[Electric vehicle supply chain|global battery supply chain]] in 2024<ref>{{cite web |date=2024 |title=Batteries and secure energy transitions |url=https://www.iea.org/reports/batteries-and-secure-energy-transitions |publisher=IEA |location=Paris}}</ref>{{rp|58}}]]

Extraction of lithium, [[nickel]], and [[cobalt]], manufacture of solvents, and mining byproducts present significant environmental and health hazards.<ref name="Amui-2020">{{cite journal  |last1=Amui  |first1=Rachid  |title=Commodities At a Glance: Special issue on strategic battery raw materials  |journal=United Nations Conference on Trade and Development  |date=February 2020  |volume=13  |issue=UNCTAD/DITC/COM/2019/5  |url=https://unctad.org/system/files/official-document/ditccom2019d5_en.pdf  |access-date=10 February 2021  |archive-date=3 February 2021  |archive-url=https://web.archive.org/web/20210203083250/https://unctad.org/system/files/official-document/ditccom2019d5_en.pdf  |url-status=live  }}</ref><ref name="USEPA-2013">{{cite report  | date = 2013  | title = Application of Life-Cycle Assessment to Nanoscale Technology: Lithium-ion Batteries for Electric Vehicles  | url = https://www.epa.gov/saferchoice/partnership-conduct-life-cycle-assessment-lithium-ion-batteries-and-nanotechnology  | publisher = U.S. Environmental Protection Agency (EPA)  | location = Washington, DC  | id = EPA 744-R-12-001  | access-date = 9 July 2017  | archive-date = 11 July 2017  | archive-url = https://web.archive.org/web/20170711070403/https://www.epa.gov/saferchoice/partnership-conduct-life-cycle-assessment-lithium-ion-batteries-and-nanotechnology  | url-status = live  }}</ref><ref name="Environmental Leader-2013">{{cite web  | title = Can Nanotech Improve Li-ion Battery Performance  | url = http://www.environmentalleader.com/2013/05/30/nanotech-can-improve-li-ion-battery-performance/ |publisher=Environmental Leader  | date = 30 May 2013 |access-date=3 June 2013 |archive-url=https://web.archive.org/web/20160821064806/http://www.environmentalleader.com/2013/05/30/nanotech-can-improve-li-ion-battery-performance/ |archive-date=21 August 2016 }}</ref> 
Lithium extraction can be fatal to aquatic life due to water pollution.<ref name="Katwala2021">{{cite magazine |last1=Katwala |first1=Amit |title=The spiralling environmental cost of our lithium battery addiction |url=https://www.wired.co.uk/article/lithium-batteries-environment-impact |magazine=Wired |publisher=Condé Nast Publications |access-date=10 February 2021 |archive-date=9 February 2021 |archive-url=https://web.archive.org/web/20210209172109/https://www.wired.co.uk/article/lithium-batteries-environment-impact |url-status=live }}</ref> It is known to cause surface water contamination, drinking water contamination, respiratory problems, ecosystem degradation and landscape damage.<ref name="Amui-2020" /> It also leads to unsustainable water consumption in arid regions (1.9 million liters per ton of lithium).<ref name="Amui-2020" /> Massive byproduct generation of lithium extraction also presents unsolved problems, such as large amounts of magnesium and lime waste.<ref name="Draper-2019">{{cite news |last1=Draper |first1=Robert  | title = This metal is powering today's technology—at what price?  | url = https://www.nationalgeographic.com/magazine/2019/02/lithium-is-fueling-technology-today-at-what-cost/ | archive-url = https://web.archive.org/web/20190118232341/https://www.nationalgeographic.com/magazine/2019/02/lithium-is-fueling-technology-today-at-what-cost/ | archive-date = 18 January 2019 |url-access=subscription |access-date=10 February 2021 |work=National Geographic |issue=February 2019 |publisher=National Geographic Partners}}</ref>

Lithium mining takes place in North and South America, Asia, South Africa, Australia, and China.<ref>{{Cite book | title = Rechargeable lithium batteries: from fundamentals to applications|others=Franco, Alejandro A.|isbn=978-1-78242-098-9|location=Cambridge, UK|publisher=Elsevier Science|oclc=907480930|last1 = Franco|first1 = Alejandro|date = 7 April 2015}}</ref>

Cobalt for Li-ion batteries is largely mined in the Congo (see also [[Mining industry of the Democratic Republic of the Congo]]). Open-pit [[Copper extraction|cobalt mining]] has led to [[Deforestation in the Democratic Republic of the Congo|deforestation]] and habitat destruction in the Democratic Republic of Congo.<ref>{{cite news |title=How 'modern-day slavery' in the Congo powers the rechargeable battery economy |url=https://www.npr.org/sections/goatsandsoda/2023/02/01/1152893248/red-cobalt-congo-drc-mining-siddharth-kara |work=[[NPR]] |date=1 February 2023}}</ref>

Open-pit [[Nickel mine|nickel mining]] has led to environmental degradation and pollution in developing countries such as the [[List of mines in the Philippines|Philippines]] and [[List of mines in Indonesia|Indonesia]].<ref>{{cite news |last1=Rick |first1=Mills |title=Indonesia and China killed the nickel market |url=https://www.mining.com/web/indonesia-and-china-killed-the-nickel-market/ |work=MINING.COM |date=4 March 2024}}</ref><ref>{{cite news |title=Land grabs and vanishing forests: Are 'clean' electric vehicles to blame? |url=https://www.aljazeera.com/news/2024/3/14/land-grabs-and-cleared-forests-why-electric-vehicles-are-getting-a-bad-rep |work=Al Jazeera |date=14 March 2024}}</ref> In 2024, nickel mining and processing was one of the main causes of [[deforestation in Indonesia]].<ref>{{cite news |title=Indonesia's massive metals build-out is felling the forest for batteries |url=https://apnews.com/article/indonesia-nickel-deforestation-rainforest-mining-tesla-ev-184550cddf1df6aad8e883862ab366df |work=AP News |date=15 July 2024}}</ref><ref>{{cite news |title=EU faces green dilemma in Indonesian nickel |url=https://www.dw.com/en/eu-faces-green-dilemma-in-sourcing-nickel-from-indonesia/a-69681557 |work=Deutsche Welle |date=16 July 2024}}</ref>

Manufacturing a kg of Li-ion battery takes about 67 [[megajoule]] (MJ) of energy.<ref>{{cite web | url = http://www.kitco.com/ind/Albrecht/2014-12-16-How-Green-is-Lithium.html | title = How "Green" is Lithium? | work = Kitco News | date = 16 December 2014 | access-date = 25 July 2016 | archive-date = 20 July 2016 | archive-url = https://web.archive.org/web/20160720160201/http://www.kitco.com/ind/Albrecht/2014-12-16-How-Green-is-Lithium.html }}</ref><ref>{{Cite web  | url = http://ec.europa.eu/environment/integration/research/newsalert/pdf/303na1_en.pdf  | title = European Commission, Science for Environment Policy, News Alert Issue 303  | date = October 2012  | access-date = 8 February 2018  | archive-date = 16 September 2018  | archive-url = https://web.archive.org/web/20180916022737/http://ec.europa.eu/environment/integration/research/newsalert/pdf/303na1_en.pdf  | url-status = live  }}</ref> The [[global warming potential]] of lithium-ion batteries manufacturing strongly depends on the energy source used in mining and manufacturing operations, and is difficult to estimate, but one 2019 study estimated 73&nbsp;kg CO2e/kWh.<ref>{{Cite web|url=https://www.transportenvironment.org/wp-content/uploads/2021/07/2019_11_Analysis_CO2_footprint_lithium-ion_batteries.pdf|title=Analysis of the climate impact of lithium-ion batteries and how to measure it|access-date=18 December 2021|archive-date=22 January 2022|archive-url=https://web.archive.org/web/20220122130933/https://www.transportenvironment.org/wp-content/uploads/2021/07/2019_11_Analysis_CO2_footprint_lithium-ion_batteries.pdf|url-status=live}}</ref> Effective recycling can reduce the carbon footprint of the production significantly.<ref>{{Cite web|url=https://www.erneuerbar-mobil.de/sites/default/files/2017-01/LithoRec%20II-LCA-Update%202016.pdf|title=Aktualisierte Ökobilanzen zum Recyclingverfahren LithoRec II für Lithium-Ionen-Batterien|last=Buchert|first=Matthias|date=14 December 2016|access-date=14 June 2019|archive-date=20 April 2019|archive-url=https://web.archive.org/web/20190420203638/https://www.erneuerbar-mobil.de/sites/default/files/2017-01/LithoRec%20II-LCA-Update%202016.pdf|url-status=live}}</ref>

=== Solid waste and recycling ===
{{Main|Battery recycling}}
According to one paper in 2019 most Li-ion batteries were recycled.<ref>{{Cite journal |last1=Linda |first1=Gaines |last2=Jingyi |first2=Zhang |last3=Xin |first3=He |last4=Jessey |first4=Bouchard |last5=Eric |first5=Melin, Hans |date=July 2023 |title=Tracking Flows of End-of-Life Battery Materials and Manufacturing Scrap |url=https://www.mdpi.com/2313-0105/9/7/360 |journal=Batteries |language=en |volume=9 |issue=7 |doi=10.3390/batterie |doi-broken-date=1 June 2025 |doi-access=free |issn=2313-0105 |archive-url=http://web.archive.org/web/20250513040432/https://www.mdpi.com/2313-0105/9/7/360 |archive-date=2025-05-13}}</ref><ref>{{Cite web |last=Ritchie |first=Hannah |title=What share of lithium-ion batteries are recycled? |url=https://www.sustainabilitybynumbers.com/p/battery-recycling-myth |access-date=2025-06-01 |website=www.sustainabilitybynumbers.com |language=en}}</ref> Li-ion battery elements including iron, copper, nickel and cobalt are considered safe for [[incinerators]] and [[landfills]].<ref>{{Cite web |last=Mitchell |first=Robert L. |date=2006-08-22 |title=Lithium ion batteries: High-tech's latest mountain of waste |url=https://www.computerworld.com/article/2482910/lithium-ion-batteries--high-tech-s-latest-mountain-of-waste.html |access-date=2022-04-22 |website=Computerworld |language=en |archive-date=22 April 2022 |archive-url=https://web.archive.org/web/20220422205547/https://www.computerworld.com/article/2482910/lithium-ion-batteries--high-tech-s-latest-mountain-of-waste.html |url-status=live }}</ref>{{Citation needed|date=October 2021}} These metals can be [[recycle]]d,<ref name="Hanisch-2015">{{cite book|last1=Hanisch|first1=Christian|title=Handbook of Clean Energy Systems – Recycling of Lithium-Ion Batteries|last2=Diekmann|first2=Jan|last3=Stieger|first3=Alexander|last4=Haselrieder |first4=Wolfgang|last5=Kwade|first5=Arno|date=2015|publisher=John Wiley & Sons, Ltd|isbn=978-1-118-99197-8 |editor1-last=Yan|editor1-first=Jinyue|edition=5 Energy Storage|pages=2865–2888|chapter=27 |doi=10.1002/9781118991978.hces221|editor2-last=Cabeza|editor2-first=Luisa F.|editor3-last=Sioshansi |editor3-first=Ramteen}}</ref><ref>{{cite web|last1=Hanisch|first1=Christian|title=Recycling of Lithium-Ion Batteries|url=http://www.lion-eng.de/images/pdf/Recycling-of-Lithium-Ion-Batteries-LionEngineering.pdf|access-date=22 July 2015|website=Presentation on Recycling of Lithium-Ion Batteries|publisher=Lion Engineering GmbH|archive-date=26 February 2017|archive-url=https://web.archive.org/web/20170226171944/http://www.lion-eng.de/images/pdf/Recycling-of-Lithium-Ion-Batteries-LionEngineering.pdf}}</ref> usually by burning away the other materials,<ref name="Morris-2020">{{cite web|last1=Morris|first1=Charles|date=27 August 2020|title=Li-Cycle recovers usable battery-grade materials from shredded Li-ion batteries|url=https://chargedevs.com/features/li-cycle-recovers-usable-battery-grade-materials-from-shredded-li-ion-batteries/|url-status=live|archive-url=https://web.archive.org/web/20200916100246/https://chargedevs.com/features/li-cycle-recovers-usable-battery-grade-materials-from-shredded-li-ion-batteries/|archive-date=16 September 2020|access-date=31 October 2020 |website=chargedevs.com|quote=thermally treat them—they're burning off plastic and electrolyte in the batteries and are not really focused on the material recovery. It's mainly the cobalt, the nickel and the copper that they can get via that method. Lithium-ion is quite a bit more complex, than lead–acid}}</ref> but mining generally remains cheaper than recycling;<ref name="Kamyamkhane-2011">{{cite web|author=Kamyamkhane, Vaishnovi |title=Are lithium batteries sustainable to the environment?|url=http://www.alternative-energy-resources.net/are-lithium-ion-batteries-sustainable-to-the-environment-i.html?|archive-url=https://web.archive.org/web/20110917012206/http://www.alternative-energy-resources.net/are-lithium-ion-batteries-sustainable-to-the-environment-i.html|archive-date=17 September 2011|access-date=3 June 2013 |publisher=Alternative Energy Resources}}</ref> and recycling may cost $3/kg.<ref>{{cite web|date=27–28 August 2019|title=R&D Insights for Extreme Fast Charging of Medium- and Heavy-Duty Vehicles|url=https://afdc.energy.gov/files/u/publication/extreme_fast_charging.pdf|publisher=[[NREL]]|page=6|quote=Some participants paid $3/kg to recycle batteries at end of life|access-date=23 October 2020|archive-date=18 October 2020|archive-url=https://web.archive.org/web/20201018040107/https://afdc.energy.gov/files/u/publication/extreme_fast_charging.pdf|url-status=live}}</ref> Since 2018, the recycling yield was increased significantly, and recovering lithium, manganese, aluminum, the organic solvents of the electrolyte, and graphite is possible at industrial scales.<ref>{{Cite web|title=ATZ WORLDWIDE|url=https://uacj-automobile.com/ebook/atz_worldwide2018/index.html#p=10|access-date=14 June 2019|website=uacj-automobile.com|archive-date=11 July 2019|archive-url=https://web.archive.org/web/20190711153343/https://uacj-automobile.com/ebook/atz_worldwide2018/index.html#p=10|url-status=live}}</ref> The most expensive metal involved in the construction of the cell is cobalt. Lithium is less expensive than other metals used and is rarely recycled,<ref name="Morris-2020" />{{Obsolete source|date=June 2025}} but recycling could prevent a future shortage.<ref name="Hanisch-2015" />

Accumulation of battery waste presents technical challenges and health hazards.<ref name="Jacoby-2019b">{{Cite news|last=Jacoby|first=Mitch|date=July 14, 2019|title=It's time to get serious about recycling lithium-ion batteries|work=Chemical & Engineering News|url=https://cen.acs.org/materials/energy-storage/time-serious-recycling-lithium/97/i28|quote=The enormousness of the impending spent-battery situation is driving researchers to search for cost-effective, environmentally sustainable strategies for dealing with the vast stockpile of Li-ion batteries looming on the horizon.;  Cobalt, nickel, manganese, and other metals found in batteries can readily leak from the casing of buried batteries and contaminate soil and groundwater, threatening ecosystems and human health...The same is true of the solution of lithium fluoride salts (LiPF6 is common) in organic solvents that are used in a battery's electrolyte|access-date=29 October 2021|archive-date=29 October 2021|archive-url=https://web.archive.org/web/20211029214517/https://cen.acs.org/materials/energy-storage/time-serious-recycling-lithium/97/i28|url-status=live}}</ref> Since the environmental impact of electric cars is heavily affected by the production of lithium-ion batteries, the development of efficient ways to repurpose waste is crucial.<ref name="Jacoby-2019a">{{Cite news |last=Jacoby |first=Mitch |date=July 14, 2019 |title=It's time to get serious about recycling lithium-ion batteries |url=https://cen.acs.org/materials/energy-storage/time-serious-recycling-lithium/97/i28 |url-status=live |archive-url=https://web.archive.org/web/20211029214517/https://cen.acs.org/materials/energy-storage/time-serious-recycling-lithium/97/i28 |archive-date=29 October 2021 |access-date=29 October 2021 |work=Chemical & Engineering News}}</ref> Recycling is a multi-step process, starting with the storage of batteries before disposal, followed by manual testing, disassembling, and finally the chemical separation of battery components. Re-use of the battery is preferred over complete recycling as there is less [[embodied energy]] in the process. As these batteries are a lot more reactive than classical vehicle waste like tire rubber, there are significant risks to stockpiling used batteries.<ref>{{Cite journal |date=2012 |title=A General Discussion of Li Ion Battery Safety |journal=Electrochemical Society Interface |doi=10.1149/2.f03122if |bibcode=2012ECSIn..21b..37D |issn=1944-8783 |last1=Doughty|first1=Daniel H.|last2=Roth|first2=E. Peter|volume=21|issue=2|page=37}}</ref>

==== Pyrometallurgical recovery ====

The [[pyrometallurgy|pyrometallurgical]] method uses a high-temperature furnace to reduce the components of the metal oxides in the battery to an alloy of Co, Cu, Fe, and Ni. This is the most common and commercially established method of recycling and can be combined with other similar batteries to increase smelting efficiency and improve [[thermodynamics]]. The metal [[current collector]]s aid the smelting process, allowing whole cells or modules to be melted at once.<ref>{{Cite journal|last1=Georgi-Maschler|first1=T.|last2=Friedrich|first2=B.|last3=Weyhe|first3=R.|last4=Heegn|first4=H.|last5=Rutz|first5=M. |date=2012-06-01 |title=Development of a recycling process for Li-ion batteries |journal=Journal of Power Sources|volume=207|pages=173–182 |doi=10.1016/j.jpowsour.2012.01.152|issn=0378-7753}}</ref> The product of this method is a collection of metallic alloy, [[slag]], and gas. At high temperatures, the polymers used to hold the battery cells together burn off and the metal alloy can be separated through a hydrometallurgical process into its separate components. The slag can be further refined or used in the [[cement]] industry. The process is relatively risk-free and the [[Exothermic process|exothermic]] reaction from polymer combustion reduces the required input energy. However, in the process, the plastics, [[electrolyte]]s, and lithium salts will be lost.<ref>{{Cite journal|last1=Lv|first1=Weiguang|last2=Wang|first2=Zhonghang|last3=Cao|first3=Hongbin|last4=Sun|first4=Yong|last5=Zhang|first5=Yi|last6=Sun|first6=Zhi | date = 2018-01-11 | title = A Critical Review and Analysis on the Recycling of Spent Lithium-Ion Batteries |journal=ACS Sustainable Chemistry & Engineering|volume=6|issue=2|pages=1504–1521 |doi=10.1021/acssuschemeng.7b03811 |issn=2168-0485}}</ref>

==== Hydrometallurgical metals reclamation ====

This method involves the use of [[aqueous solution]]s to remove the desired metals from the cathode. The most common reagent is [[sulfuric acid]].<ref>{{Cite journal|last1=Ferreira|first1=Daniel Alvarenga |last2=Prados |first2=Luisa Martins Zimmer |last3=Majuste|first3=Daniel |last4=Mansur|first4=Marcelo Borges  | date = 2009-02-01 | title = Hydrometallurgical separation of aluminium, cobalt, copper and lithium from spent Li-ion batteries |journal=Journal of Power Sources|volume=187|issue=1|pages=238–246  | doi = 10.1016/j.jpowsour.2008.10.077|bibcode=2009JPS...187..238F |issn=0378-7753}}</ref> Factors that affect the leaching rate include the concentration of the acid, time, temperature, solid-to-liquid-ratio, and [[reducing agent]].<ref>{{Cite journal|last1=He|first1=Li-Po |last2=Sun|first2=Shu-Ying |last3=Song|first3=Xing-Fu |last4=Yu|first4=Jian-Guo |date=June 2017 |title=Leaching process for recovering valuable metals from the LiNi 1/3 Co 1/3 Mn 1/3 O 2 cathode of lithium-ion batteries |journal=Waste Management|volume=64|pages=171–181 |doi=10.1016/j.wasman.2017.02.011|pmid=28325707 |bibcode=2017WaMan..64..171H |issn=0956-053X}}</ref> It is experimentally proven that H<sub>2</sub>O<sub>2</sub> acts as a reducing agent to speed up the rate of [[Leaching (metallurgy)|leaching]] through the reaction:<ref>{{Cite journal |last=Li |first=Liang |date=2010-03-15 |title=Recovery of cobalt and lithium from spent lithium ion batteries using organic citric acid as leachant |url=https://pubmed.ncbi.nlm.nih.gov/19954882/ |access-date=2025-05-28 |journal=Journal of Hazardous Materials |volume=176 |issue=1–3 |pages=288–293 |doi=10.1016/j.jhazmat.2009.11.026 |pmid=19954882 |bibcode=2010JHzM..176..288L |quote=H₂O₂ was used as a reducing agent to enhance the leaching efficiency of cobalt and lithium.}}</ref>

: 2 LiCoO<sub>2</sub> <sub>(s)</sub> + 3 H<sub>2</sub>SO<sub>4</sub> + H<sub>2</sub>O<sub>2</sub> → 2 CoSO<sub>4</sub> <sub>(aq)</sub> + Li<sub>2</sub>SO<sub>4</sub> + 4 H<sub>2</sub>O + O<sub>2</sub>

Once leached, the metals can be extracted through [[Precipitation (chemistry)|precipitation]] reactions controlled by changing the pH level of the solution. Cobalt, the most expensive metal, can then be recovered in the form of sulfate, oxalate, hydroxide, or carbonate. [75] More recently,{{When|date=April 2025}} recycling methods experiment with the direct reproduction of the cathode from the leached metals. In these procedures, concentrations of the various leached metals are premeasured to match the target cathode and then the cathodes are directly synthesized.<ref>{{Cite journal|last1=Sa|first1=Qina |last2=Gratz|first2=Eric |last3=Heelan|first3=Joseph A. |last4=Ma|first4=Sijia |last5=Apelian|first5=Diran |last6=Wang|first6=Yan  | date = 2016-04-04 | title = Synthesis of Diverse LiNixMnyCozO2 Cathode Materials from Lithium Ion Battery Recovery Stream|journal=Journal of Sustainable Metallurgy|volume=2|issue=3|pages=248–256  | doi = 10.1007/s40831-016-0052-x|bibcode=2016JSusM...2..248S |s2cid=99466764 |issn=2199-3823|doi-access=free}}</ref>

The main issues with this method, however, are the large volume of [[solvent]] required and the high cost of neutralization. Although it is easy to shred up the battery, mixing the cathode and anode at the beginning complicates the process, so they will also need to be separated. Unfortunately, the current design of batteries makes the process extremely complex and it is difficult to separate the metals in a closed-loop battery system. Shredding and dissolving may occur at different locations.<ref>{{cite web |title=Li-ion battery recycling company Li-Cycle closes Series C round |url=https://www.greencarcongress.com/2020/11/20201119-licycle.html |website=Green Car Congress |archive-url=https://web.archive.org/web/20201129011325/https://www.greencarcongress.com/2020/11/20201119-licycle.html |archive-date=29 November 2020 |date=29 November 2020 |url-status=live}}</ref>

==== Direct recycling ====

Direct recycling is the removal of the cathode or anode from the electrode, reconditioned, and then reused in a new battery. Mixed metal-oxides can be added to the new electrode with very little change to the crystal morphology. The process generally involves the addition of new lithium to replenish the loss of lithium in the cathode due to degradation from cycling. Cathode strips are obtained from the dismantled batteries, then soaked in [[N-Methyl-2-pyrrolidone|NMP]], and undergo sonication to remove excess deposits. It is treated hydrothermally with a solution containing LiOH/Li<sub>2</sub>SO<sub>4</sub> before annealing.<ref>{{Cite journal|last1=Shi |first1=Yang|last2=Chen |first2=Gen|last3=Liu|first3=Fang|last4=Yue|first4=Xiujun|last5=Chen|first5=Zheng |date=2018-06-26 |title=Resolving the Compositional and Structural Defects of Degraded LiNixCoyMnzO2 Particles to Directly Regenerate High-Performance Lithium-Ion Battery Cathodes |journal=ACS Energy Letters|volume=3 |issue=7|pages=1683–1692|doi=10.1021/acsenergylett.8b00833 |s2cid=139435709|issn=2380-8195}}</ref>

This method is extremely cost-effective for noncobalt-based batteries as the raw materials do not make up the bulk of the cost. Direct recycling avoids the time-consuming and expensive purification steps, which is great for low-cost cathodes such as LiMn<sub>2</sub>O<sub>4</sub> and LiFePO<sub>4</sub>. For these cheaper cathodes, most of the cost, embedded energy, and [[carbon footprint]] is associated with the manufacturing rather than the raw material.<ref>{{Cite journal|last1=Dunn|first1=Jennifer B.|last2=Gaines|first2=Linda|last3=Sullivan|first3=John|last4=Wang|first4=Michael Q. |date=2012-10-30 |title=Impact of Recycling on Cradle-to-Gate Energy Consumption and Greenhouse Gas Emissions of Automotive Lithium-Ion Batteries |journal=Environmental Science & Technology|volume=46|issue=22|pages=12704–12710 |doi=10.1021/es302420z|pmid=23075406|bibcode=2012EnST...4612704D|issn=0013-936X}}</ref> It is experimentally shown that direct recycling can reproduce similar properties to pristine graphite.

The drawback of the method lies in the condition of the retired battery. In the case where the battery is relatively healthy, direct recycling can cheaply restore its properties. However, for batteries where the state of charge is low, direct recycling may not be worth the investment. The process must also be tailored to the specific cathode composition, and therefore the process must be configured to one type of battery at a time.<ref>{{Cite journal | date = April 2019 | title = Recycle spent batteries|journal=Nature Energy|volume=4|issue=4|page=253 | doi = 10.1038/s41560-019-0376-4|bibcode=2019NatEn...4..253.|s2cid=189929222|issn=2058-7546|doi-access=free}}</ref> Lastly, in a time with rapidly developing battery technology, the design of a battery today may no longer be desirable a decade from now, rendering direct recycling ineffective.

====Physical materials separation====
Physical materials separation recovered materials by mechanical crushing and exploiting physical properties of different components such as particle size, density, ferromagnetism and hydrophobicity. Copper, aluminum and steel casing can be recovered by sorting. The remaining materials, called "black mass", which is composed of nickel, cobalt, lithium and manganese, need a secondary treatment to recover.<ref name="Ciez-2019">{{cite journal |last1=Ciez |first1=Rebecca E. |last2=Whitacre |first2=J. F. |date=February 2019 |title=Examining different recycling processes for lithium-ion batteries |journal=Nature Sustainability |volume=2 |issue=2 |pages=148–156 |doi=10.1038/s41893-019-0222-5 |bibcode=2019NatSu...2..148C |issn=2398-9629 |s2cid=188116440}}</ref>

====Biological metals reclamation====
For the biological metals reclamation or bio-leaching, the process uses microorganisms to digest metal oxides selectively. Then, recyclers can reduce these oxides to produce metal nanoparticles. Although bio-leaching has been used successfully in the mining industry, this process is still nascent to the recycling industry and plenty of opportunities exists for further investigation.<ref name="Ciez-2019"/>

==== Electrolyte recycling ====
Electrolyte recycling consists of two phases. The collection phase extracts the electrolyte from the spent Li-ion battery. This can be achieved through mechanical processes, [[distillation]], freezing, [[Liquid–liquid extraction|solvent extraction]], and [[supercritical fluid extraction]]. Due to the volatility, flammability, and sensitivity of the electrolyte, the collection process poses a greater difficulty than the collection process for other components of a Li-ion battery. The next phase consists of separation/electrolyte regeneration. Separation consists of isolating the individual components of the electrolyte. This approach is often used for the direct recovery of the Li salts from the organic solvents. In contrast, regeneration of the electrolyte aims to preserve the electrolyte composition by removing impurities which can be achieved through filtration methods.<ref>{{Cite journal |last1=Niu |first1=Bo |last2=Xu |first2=Zhenming |last3=Xiao |first3=Jiefeng |last4=Qin |first4=Yufei |date=2023-07-12 |title=Recycling Hazardous and Valuable Electrolyte in Spent Lithium-Ion Batteries: Urgency, Progress, Challenge, and Viable Approach |url=https://pubs.acs.org/doi/10.1021/acs.chemrev.3c00174 |journal=Chemical Reviews |language=en |volume=123 |issue=13 |pages=8718–8735 |doi=10.1021/acs.chemrev.3c00174 |pmid=37339582 |issn=0009-2665}}</ref><ref>{{Cite journal |last1=Zhang |first1=Ruihan |last2=Shi |first2=Xingyi |last3=Esan |first3=Oladapo Christopher |last4=An |first4=Liang |date=2022-06-11 |title=Organic Electrolytes Recycling From Spent Lithium-Ion Batteries |journal=Global Challenges |language=en |volume=6 |issue=12 |doi=10.1002/gch2.202200050 |issn=2056-6646 |pmc=9749074 |pmid=36532239|bibcode=2022GloCh...600050Z }}</ref>

The recycling of the electrolytes, which consists 10-15 wt.% of the Li-ion battery, provides both an economic and environmental benefits. These benefits include the recovery of the valuable Li-based salts and the prevention of hazardous compounds, such as volatile organic compounds ([[Volatile organic compound|VOCs]]) and carcinogens, being released into the environment.

Compared to electrode recycling, less focus is placed on recycling the electrolyte of Li-ion batteries which can be attributed to lower economic benefits and greater process challenges. Such challenges can include the difficulty associated with recycling different electrolyte compositions,<ref>{{Cite journal |last1=Wang |first1=Qingsong |last2=Jiang |first2=Lihua |last3=Yu |first3=Yan |last4=Sun |first4=Jinhua |date=2019-01-01 |title=Progress of enhancing the safety of lithium ion battery from the electrolyte aspect |url=https://linkinghub.elsevier.com/retrieve/pii/S2211285518307614 |journal=Nano Energy |volume=55 |pages=93–114 |doi=10.1016/j.nanoen.2018.10.035 |bibcode=2019NEne...55...93W |issn=2211-2855}}</ref> removing side products accumulated from electrolyte decomposition during its runtime,<ref>{{Cite journal |last1=Mönnighoff |first1=Xaver |last2=Friesen |first2=Alex |last3=Konersmann |first3=Benedikt |last4=Horsthemke |first4=Fabian |last5=Grützke |first5=Martin |last6=Winter |first6=Martin |last7=Nowak |first7=Sascha |date=2017-06-01 |title=Supercritical carbon dioxide extraction of electrolyte from spent lithium ion batteries and its characterization by gas chromatography with chemical ionization |url=https://linkinghub.elsevier.com/retrieve/pii/S0378775317304202 |journal=Journal of Power Sources |volume=352 |pages=56–63 |doi=10.1016/j.jpowsour.2017.03.114 |bibcode=2017JPS...352...56M |issn=0378-7753}}</ref> and removal of electrolyte adsorbed onto the electrodes.<ref>{{Cite journal |last1=Zhang |first1=Xiaoxiao |last2=Li |first2=Li |last3=Fan |first3=Ersha |last4=Xue |first4=Qing |last5=Bian |first5=Yifan |last6=Wu |first6=Feng |last7=Chen |first7=Renjie |date=2018 |title=Toward sustainable and systematic recycling of spent rechargeable batteries |url=https://xlink.rsc.org/?DOI=C8CS00297E |journal=Chemical Society Reviews |language=en |volume=47 |issue=19 |pages=7239–7302 |doi=10.1039/C8CS00297E |pmid=30124695 |issn=0306-0012}}</ref> Due to these challenges, current pyrometallurgical methods of Li-ion battery recycling forgo electrolyte recovery, releasing hazardous gases upon heating. However, due to high energy consumption and environmental impact, future recycling methods are being directed away from this approach.<ref>{{Cite journal |last1=Arshad |first1=Faiza |last2=Li |first2=Li |last3=Amin |first3=Kamran |last4=Fan |first4=Ersha |last5=Manurkar |first5=Nagesh |last6=Ahmad |first6=Ali |last7=Yang |first7=Jingbo |last8=Wu |first8=Feng |last9=Chen |first9=Renjie |date=2020-09-14 |title=A Comprehensive Review of the Advancement in Recycling the Anode and Electrolyte from Spent Lithium Ion Batteries |url=https://pubs.acs.org/doi/10.1021/acssuschemeng.0c04940 |journal=ACS Sustainable Chemistry & Engineering |language=en |volume=8 |issue=36 |pages=13527–13554 |doi=10.1021/acssuschemeng.0c04940 |issn=2168-0485}}</ref>

=== Human rights impact ===
Extraction of raw materials for lithium-ion batteries may present dangers to local people, especially land-based indigenous populations.<ref>{{Cite journal |last1=Agusdinata |first1=Datu Buyung |last2=Liu |first2=Wenjuan |last3=Eakin |first3=Hallie |last4=Romero |first4=Hugo |date=2018-11-27 |title=Socio-environmental impacts of lithium mineral extraction: towards a research agenda |journal=Environmental Research Letters |volume=13 |issue=12 |page=123001 |doi=10.1088/1748-9326/aae9b1 |bibcode=2018ERL....13l3001B |s2cid=159013281 |issn=1748-9326|doi-access=free }}</ref>

[[Cobalt#Democratic Republic of the Congo|Cobalt sourced from the Democratic Republic of the Congo]] is often mined by workers using hand tools with few safety precautions, resulting in frequent injuries and deaths.<ref>{{Cite news|last1=Mucha|first1=Lena|last2=Sadof|first2=Karly Domb|last3=Frankel|first3=Todd C.|date=2018-02-28|title=Perspective – The hidden costs of cobalt mining|language=en-US|newspaper=The Washington Post|url=https://www.washingtonpost.com/news/in-sight/wp/2018/02/28/the-cost-of-cobalt/|access-date=2018-03-07|issn=0190-8286|archive-date=10 April 2019|archive-url=https://web.archive.org/web/20190410171546/https://www.washingtonpost.com/news/in-sight/wp/2018/02/28/the-cost-of-cobalt/|url-status=live}}</ref> Pollution from these mines has exposed people to toxic chemicals that health officials believe to cause birth defects and breathing difficulties.<ref>{{cite news|author=Todd C. Frankel|date=September 30, 2016|title=THE COBALT PIPELINE: Tracing the path from deadly hand-dug mines in Congo to consumers' phones and laptops|newspaper=The Washington Post|url=https://www.washingtonpost.com/graphics/business/batteries/congo-cobalt-mining-for-lithium-ion-battery/|access-date=29 October 2021|archive-date=17 April 2019|archive-url=https://web.archive.org/web/20190417134443/https://www.washingtonpost.com/graphics/business/batteries/congo-cobalt-mining-for-lithium-ion-battery/|url-status=live}}</ref> Human rights activists have alleged, and [[investigative journalism]] reported confirmation,<ref>Crawford, Alex. [http://news.sky.com/story/meet-dorsen-8-who-mines-cobalt-to-make-your-smartphone-work-10784120 Meet Dorsen, 8, who mines cobalt to make your smartphone work] {{Webarchive|url=https://web.archive.org/web/20180907130830/https://news.sky.com/story/meet-dorsen-8-who-mines-cobalt-to-make-your-smartphone-work-10784120 |date=7 September 2018 }}. ''Sky News UK''. Retrieved on 2018-01-07.</ref><ref>[http://news.sky.com/video/are-you-holding-a-product-of-child-labour-right-now-10785338 Are you holding a product of child labour right now? (Video)] {{Webarchive|url=https://web.archive.org/web/20180701194026/https://news.sky.com/video/are-you-holding-a-product-of-child-labour-right-now-10785338 |date=1 July 2018 }}. ''Sky News UK'' (2017-02-28). Retrieved on 2018-01-07.</ref> that [[child labor]] is used in these mines.<ref name="Frankel-2016">{{cite news|last1=Frankel|first1=Todd C.|date=2016-09-30|title=Cobalt mining for lithium ion batteries has a high human cost|url=https://www.washingtonpost.com/graphics/business/batteries/congo-cobalt-mining-for-lithium-ion-battery/|access-date=2016-10-18|newspaper=[[The Washington Post]]|archive-date=17 April 2019|archive-url=https://web.archive.org/web/20190417134443/https://www.washingtonpost.com/graphics/business/batteries/congo-cobalt-mining-for-lithium-ion-battery/|url-status=live}}</ref>

A study of relationships between lithium extraction companies and indigenous peoples in Argentina indicated that the state may not have protected indigenous peoples' right to [[Free, prior and informed consent|free prior and informed consent]], and that extraction companies generally controlled community access to information and set the terms for discussion of the projects and benefit sharing.<ref>{{Cite journal|last1=Marchegiani |first1=Pia |last2=Morgera |first2=Elisa |last3=Parks |first3=Louisa |date=November 21, 2019|title=Indigenous peoples' rights to natural resources in Argentina: the challenges of impact assessment, consent and fair andequitable benefit-sharing in cases of lithium mining |journal=The International Journal of Human Rights |url=https://www.researchgate.net/publication/337431438}}</ref>

Development of the [[Thacker Pass Lithium Mine|Thacker Pass lithium mine]] in Nevada, USA has met with protests and lawsuits from several indigenous tribes who have said they were not provided free prior and informed consent and that the project threatens cultural and sacred sites.<ref>{{Cite journal|last=Price|first=Austin|date=Summer 2021|title=The Rush for White Gold|url=https://www.earthisland.org/journal/index.php/magazine/entry/the-rush-for-white-gold/|journal=Earth Island Journal|access-date=29 October 2021|archive-date=29 October 2021|archive-url=https://web.archive.org/web/20211029004245/https://www.earthisland.org/journal/index.php/magazine/entry/the-rush-for-white-gold/|url-status=live}}</ref> Links between resource extraction and [[Missing and murdered Indigenous women|missing and murdered indigenous women]] have also prompted local communities to express concerns that the project will create risks to indigenous women.<ref>{{Cite news|last=Chadwell|first=Jeri|date=July 21, 2021|title=Judge to decide on injunction request to halt work on Thacker Pass lithium mine|work=This is Reno|url=https://thisisreno.com/2021/07/judge-to-decide-on-injunction-request-to-halt-work-on-thacker-pass-lithium-mine/|access-date=October 12, 2021|archive-date=29 October 2021|archive-url=https://web.archive.org/web/20211029101346/https://thisisreno.com/2021/07/judge-to-decide-on-injunction-request-to-halt-work-on-thacker-pass-lithium-mine/|url-status=live}}</ref> Protestors have been occupying the site of the proposed mine since January, 2021.<ref name="NWT-2021">{{cite news|date=6 May 2021|title=The Lithium Gold Rush: Inside the Race to Power Electric Vehicles|work=The New York Times|url=https://www.nytimes.com/2021/05/06/business/lithium-mining-race.html|access-date=6 May 2021|archive-date=6 May 2021|archive-url=https://web.archive.org/web/20210506143008/https://www.nytimes.com/2021/05/06/business/lithium-mining-race.html|url-status=live}}</ref><ref>{{Cite news|date=January 19, 2021|title=Thacker Pass Lithium mine approval draws around-the-clock protest|work=Sierra Nevada Ally|url=https://sierranevadaally.org/2021/01/19/thacker-pass-lithium-mine-approval-draws-around-the-clock-protest/|access-date=March 16, 2021|archive-date=29 October 2021|archive-url=https://web.archive.org/web/20211029145314/https://www.sierranevadaally.org/2021/01/19/thacker-pass-lithium-mine-approval-draws-around-the-clock-protest/|url-status=live}}</ref>

== Research ==
{{main|Research in lithium-ion batteries}}
Researchers are actively working to improve the power density, safety, cycle durability (battery life), recharge time, cost, flexibility, and other characteristics, as well as research methods and uses, of these batteries. [[Solid-state battery|Solid-state batteries]] are being researched as a breakthrough in technological barriers. Currently, [[Solid-state battery|solid-state batteries]] are expected to be the most promising next-generation battery, and various companies are working to popularize them.

Research areas for lithium-ion batteries include extending lifetime, increasing energy density, improving safety, reducing cost, and increasing charging speed,<ref>{{cite journal | doi = 10.1021/acssuschemeng.7b00046 | title = Lithium-Ion Batteries with High Rate Capabilities |last= Eftekhari| first= Ali| year=2017| journal=ACS Sustainable Chemistry & Engineering| volume=5|issue=3|pages=2799–2816 }}</ref><ref>{{Cite web |title=Rising Lithium Costs Threaten Grid-Scale Energy Storage – News |url=https://eepower.com/news/rising-lithium-costs-threaten-grid-scale-energy-storage/ |access-date=2022-11-02 |website=eepower.com |language=en |archive-date=9 June 2022 |archive-url=https://web.archive.org/web/20220609180453/https://eepower.com/news/rising-lithium-costs-threaten-grid-scale-energy-storage/ |url-status=live }}</ref> among others. Research has been under way in the area of non-flammable electrolytes as a pathway to increased safety based on the flammability and volatility of the organic solvents used in the typical electrolyte. Strategies include [[Aqueous lithium-ion battery|aqueous lithium-ion batteries]], ceramic solid electrolytes, polymer electrolytes, ionic liquids, and heavily fluorinated systems.<ref>{{Cite news|url=https://www.futurity.org/lithium-ion-batteries-1606992-2/ |title=Watch: Cuts and dunks don't stop new lithium-ion battery – Futurity|last=Hopkins|first=Gina|date=16 November 2017|work=Futurity|access-date=10 July 2018|archive-date=10 July 2018|archive-url=https://web.archive.org/web/20180710195029/https://www.futurity.org/lithium-ion-batteries-1606992-2/|url-status=live}}</ref><ref>{{Cite journal | last1 = Chawla | first1 = N. | last2 = Bharti | first2 = N. | last3 = Singh | first3 = S. |doi = 10.3390/batteries5010019 | title = Recent Advances in Non-Flammable Electrolytes for Safer Lithium-Ion Batteries| journal = Batteries| volume = 5 | page = 19 | year = 2019 | doi-access = free }}</ref><ref>{{Cite journal | last1 = Yao | first1 = X.L. | last2 = Xie | first2 = S. | last3 = Chen | first3 = C. | last4 = Wang | first4 = Q.S. |last5 = Sun | first5 = J. |last6 = Wang | first6 = Q.S. |last7 = Sun | first7 = J. |doi = 10.1016/j.jpowsour.2004.11.042| title = Comparative study of trimethyl phosphite and trimethyl phosphate as electrolyte additives in lithium ion batteries| journal = Journal of Power Sources| volume = 144 | pages = 170–175 |year = 2004 }}</ref><ref>{{Cite journal | last1 = Fergus | first1 = J.W. | doi = 10.1016/j.jpowsour.2010.01.076| title = Ceramic and polymeric solid electrolytes for lithium-ion batteries| journal = Journal of Power Sources| volume = 195 | issue = 15 | pages = 4554–4569 |year = 2010 | bibcode = 2010JPS...195.4554F }}</ref>

One of the ways to improve batteries is to combine the various cathode materials. This allows researchers to improve on the qualities of a material, while limiting the negatives. One possibility is coating lithium nickel manganese oxide with lithium iron phosphate through resonant acoustic mixing. The resulting material benefits from an increase electrochemical performance and improved capacity retention.<ref>{{Cite journal |last1=Versaci |first1=Daniele |last2=Colombo |first2=Roberto |last3=Montinaro |first3=Giorgio |last4=Buga |first4=Mihaela |last5=Cortes Felix |first5=Noelia |last6=Evans |first6=Gary |last7=Bella |first7=Federico |last8=Amici |first8=Julia |last9=Francia |first9=Carlotta |last10=Bodoardo |first10=Silvia |date=2024-09-01 |title=Tailoring cathode materials: A comprehensive study on LNMO/LFP blending for next generation lithium-ion batteries |journal=Journal of Power Sources |volume=613 |page=234955 |doi=10.1016/j.jpowsour.2024.234955 |bibcode=2024JPS...61334955V |issn=0378-7753|doi-access=free }}</ref> Similar work was done with iron (III) phosphate.<ref>{{Cite journal |last1=Yi |first1=Ting-Feng |last2=Li |first2=Yan-Mei |last3=Li |first3=Xiao-Ya |last4=Pan |first4=Jing-Jing |last5=Zhang |first5=Qianyu |last6=Zhu |first6=Yan-Rong |date=2017-07-30 |title=Enhanced electrochemical property of FePO4-coated LiNi0.5Mn1.5O4 as cathode materials for Li-ion battery |url=https://linkinghub.elsevier.com/retrieve/pii/S2095927317303481 |journal=Science Bulletin |volume=62 |issue=14 |pages=1004–1010 |doi=10.1016/j.scib.2017.07.003 |pmid=36659491 |issn=2095-9273}}</ref> 
As it is now accepted that not only transition metals, but also anions in cathodes participate in redox activity necessary for Lithium insertion and removal, the design of cathode materials with diverse transition metal cations increasingly consider also oxygen redox reactions in lithium-ion battery cathodes and how these may enhance capacity beyond transition metal limitations, with computational studies using density functional theory helping to optimize materials while minimizing structural degradation. Advances in anionic redox understanding have led to stabilization strategies like surface fluorination, improving cycling stability and safety. <ref name=oxred />

== See also ==
{{Portal|Energy|Manufacturing}}
* [[Anode-free battery]]
* [[Blade battery]]
* [[Borate oxalate]]
* [[Comparison of commercial battery types]]
* [[European Battery Alliance]]
* [[Flow battery]]
* [[Nanowire battery]]
* [[Sodium-ion battery]]
* [[Thin-film lithium-ion battery]]
* [[VRLA battery]]
* [[Ultium]]

== References ==
{{reflist}}<ref>{{Cite web |last=Tripathi |first=P.K. |title=Handbook on Production, Recycling of Lithium Ion and Lead-Acid Batteries (with Manufacturing Process, Machinery Equipment Details & Plant Layout) |url=https://www.niir.org/books/book/handbook-on-production-recycling-lithium-ion-lead-acid-batteries-with-manufacturing-process-machinery-equipment-details-plant-layout-2nd-edition/isbn-9788195577507/zb,,18bd9,a,89,0,a/index.html |access-date=2025-06-09 |website=www.niir.org |language=en}}</ref>

== Sources ==

{{Refbegin}}
* {{cite book |author-first=Davide |author-last=Andrea |url=http://book.liionbms.com/ |title=Battery Management Systems for Large Lithium-Ion Battery Packs |publisher=Artech House |page=234 |isbn=978-1-60807-104-3 |year=2010 |access-date=3 June 2013 |archive-date=21 August 2013 |archive-url=https://web.archive.org/web/20130821183632/http://book.liionbms.com/ |url-status=live }}
* {{cite journal |doi=10.1021/cr020730k |journal=Chemical Reviews |title=What Are Batteries, Fuel Cells, and Supercapacitors? |volume=104 |issue=10 |pages=4245–4269 |year=2004 |pmid=15669155 |last1=Winter |first1=M |last2=Brodd |first2=RJ |doi-access=free}}
{{Refend}}

== External links ==
{{Commons category|Lithium-ion batteries}}
{{Scholia|topic}}

* {{Britannica|1085580|Lithium-ion Battery}}.
* [https://www.statista.com/statistics/1246713/largest-lithium-ion-battery-factories-worldwide/ List of World's Largest Lithium-ion Battery Factories (2020)].
* [https://web.archive.org/web/20170207004939/http://www.nrel.gov/transportation/energystorage/safety.html Energy Storage Safety at National Renewable Energy Laboratory (NREL)].
* [https://www.nytimes.com/2021/09/08/technology/batteries-new-technology.html New More Efficient Lithium-ion Batteries] ''[[The New York Times]]''. September 2021.
* [https://web.archive.org/web/20160301144207/http://www.nrel.gov/news/features/2015/21589 NREL Innovation Improves Safety of Electric Vehicle Batteries], [[National Renewable Energy Laboratory|NREL]], October 2015.
* [http://www.nrel.gov/docs/fy15osti/64171.pdf Degradation Mechanisms and Lifetime Prediction for Lithium-Ion Batteries], [[National Renewable Energy Laboratory|NREL]], July 2015.
* [https://purl.fdlp.gov/GPO/gpo41672 Impact of Temperature Extremes on Large Format Li-ion Batteries for Vehicle Applications], [[National Renewable Energy Laboratory|NREL]], March 2013.

{{Galvanic cells}}
{{Alternative propulsion}}
{{Authority control}}

[[Category:Japanese inventions]]
[[Category:Lithium-ion batteries| ]]
[[Category:20th-century inventions]]
[[Category:Metal-ion batteries]]
[[Category:American inventions]]
[[Category:English inventions]]