Editing Electrode (section)

=== Anodes ===
The anodes used in mass-produced Li-ion batteries are either carbon based (usually graphite) or made out of spinel lithium titanate (Li<sub>4</sub>Ti<sub>5</sub>O<sub>12</sub>).<ref name="sigma"/> Graphite anodes have been successfully implemented in many modern commercially available batteries due to its cheap price, longevity and high energy density.<ref>{{cite journal |last1=Zhang |first1=Hao |last2=Yang |first2=Yang |last3=Ren |first3=Dongsheng |last4=Wang |first4=Li |last5=He |first5=Xiangming |date=2021-04-01 |title=Graphite as anode materials: Fundamental mechanism, recent progress and advances |url=https://www.sciencedirect.com/science/article/pii/S2405829720304906 |journal=Energy Storage Materials |language=en |volume=36 |pages=147–170 |doi=10.1016/j.ensm.2020.12.027 |bibcode=2021EneSM..36..147Z |s2cid=233072977 |issn=2405-8297}}</ref> However, it presents issues of dendrite growth, with risks of shorting the battery and posing a safety issue.<ref>{{cite journal |last1=Zhao |first1=Qiang |last2=Hao |first2=Xiaoge |last3=Su |first3=Shiming |last4=Ma |first4=Jiabin |last5=Hu |first5=Yi |last6=Liu |first6=Yong |last7=Kang |first7=Feiyu |last8=He |first8=Yan-Bing |date=2019 |title=Expanded-graphite embedded in lithium metal as dendrite-free anode of lithium metal batteries |url=http://xlink.rsc.org/?DOI=C9TA04240G |journal=Journal of Materials Chemistry A |language=en |volume=7 |issue=26 |pages=15871–15879 |doi=10.1039/C9TA04240G |s2cid=195381622 |issn=2050-7488}}</ref> Li<sub>4</sub>Ti<sub>5</sub>O<sub>12</sub> has the second largest market share of anodes, due to its stability and good rate capability, but with challenges such as low capacity.<ref>{{cite journal |last1=Zhang |first1=Hao |last2=Yang |first2=Yang |last3=Xu |first3=Hong |last4=Wang |first4=Li |last5=Lu |first5=Xia |last6=He |first6=Xiangming |date=April 2022 |title=Li 4 Ti 5 O 12 spinel anode: Fundamentals and advances in rechargeable batteries |journal=InfoMat |language=en |volume=4 |issue=4 |doi=10.1002/inf2.12228 |issn=2567-3165|doi-access=free }}</ref> During the early 2000s, silicon anode research began picking up pace, becoming one of the decade's most promising candidates for future lithium-ion battery anodes.<ref name=":0"/> Silicon has one of the highest gravimetric capacities when compared to graphite and  Li<sub>4</sub>Ti<sub>5</sub>O<sub>12</sub> as well as a high volumetric one. Furthermore, Silicon has the advantage of operating under a reasonable open circuit voltage without parasitic lithium reactions.<ref>{{cite journal |last=Zhang |first=Wei-Jun |date=2011-01-01 |title=A review of the electrochemical performance of alloy anodes for lithium-ion batteries |url=https://www.sciencedirect.com/science/article/pii/S0378775310011699 |journal=Journal of Power Sources |language=en |volume=196 |issue=1 |pages=13–24 |doi=10.1016/j.jpowsour.2010.07.020 |bibcode=2011JPS...196...13Z |issn=0378-7753}}</ref><ref>{{cite journal |last1=Liang |first1=Bo |last2=Liu |first2=Yanping |last3=Xu |first3=Yunhua |date=2014-12-01 |title=Silicon-based materials as high capacity anodes for next generation lithium ion batteries |url=https://www.sciencedirect.com/science/article/pii/S0378775314007897 |journal=Journal of Power Sources |language=en |volume=267 |pages=469–490 |doi=10.1016/j.jpowsour.2014.05.096 |bibcode=2014JPS...267..469L |issn=0378-7753}}</ref> However, silicon anodes have a major issue of volumetric expansion during lithiation of around 360%.<ref>{{cite journal |last1=Li |first1=Xiaolin |last2=Gu |first2=Meng |last3=Hu |first3=Shenyang |last4=Kennard |first4=Rhiannon |last5=Yan |first5=Pengfei |last6=Chen |first6=Xilin |last7=Wang |first7=Chongmin |last8=Sailor |first8=Michael J. |last9=Zhang |first9=Ji-Guang |last10=Liu |first10=Jun |date=2014-07-08 |title=Mesoporous silicon sponge as an anti-pulverization structure for high-performance lithium-ion battery anodes |journal=Nature Communications |language=en |volume=5 |issue=1 |pages=4105 |doi=10.1038/ncomms5105 |pmid=25001098 |issn=2041-1723|doi-access=free |bibcode=2014NatCo...5.4105L }}</ref> This expansion may pulverize the anode, resulting in poor performance.<ref>{{cite journal |last1=Zhang |first1=Huigang |last2=Braun |first2=Paul V. |date=2012-06-13 |title=Three-Dimensional Metal Scaffold Supported Bicontinuous Silicon Battery Anodes |url=https://pubs.acs.org/doi/10.1021/nl204551m |journal=Nano Letters |language=en |volume=12 |issue=6 |pages=2778–2783 |doi=10.1021/nl204551m |pmid=22582709 |bibcode=2012NanoL..12.2778Z |issn=1530-6984}}</ref> To fix this problem, scientists looked into varying the dimensionality of the Si.<ref name=":0">{{cite journal |last1=Zuo |first1=Xiuxia |last2=Zhu |first2=Jin |last3=Müller-Buschbaum |first3=Peter |last4=Cheng |first4=Ya-Jun |date=2017-01-01 |title=Silicon based lithium-ion battery anodes: A chronicle perspective review |url=https://www.sciencedirect.com/science/article/pii/S2211285516304931 |journal=Nano Energy |language=en |volume=31 |pages=113–143 |doi=10.1016/j.nanoen.2016.11.013 |bibcode=2017NEne...31..113Z |issn=2211-2855}}</ref> Many studies have been developed in [[Silicon nanowire|Si nanowires]], Si tubes as well as Si sheets.<ref name=":0" /> As a result, composite hierarchical Si anodes have become the major technology for future applications in lithium-ion batteries. In the early 2020s, technology is reaching commercial levels with factories being built for mass production of anodes in the United States.<ref>{{cite web |last=Ohnsman |first=Alan |title=Ex-Tesla Engineer Building Silicon Anode Plant As U.S. Amps Up EV Battery Production |url=https://www.forbes.com/sites/alanohnsman/2022/05/03/ex-tesla-engineer-building-silicon-anode-plant-as-us-amps-up-ev-battery-production/ |access-date=2022-11-19 |website=Forbes |language=en}}</ref>  Furthermore, metallic lithium is another possible candidate for the anode. It boasts a higher specific capacity than silicon, however, does come with the drawback of working with the highly unstable metallic lithium.<ref name="cen.acs.org">{{cite web |url=https://cen.acs.org/materials/energy-storage/battery-materials-world-anodes-time/97/i14 | title=In the battery materials world, the anode's time has come | author=Alex Scott | date=April 7, 2019  |access-date=2022-11-19 |website=cen.acs.org}}</ref> Similarly to graphite anodes, dendrite formation is another major limitation of metallic lithium, with the solid electrolyte interphase being a major design challenge.<ref>{{cite journal |last1=Liu |first1=Bin |last2=Zhang |first2=Ji-Guang |last3=Xu |first3=Wu |date=2018-05-16 |title=Advancing Lithium Metal Batteries |journal=Joule |language=English |volume=2 |issue=5 |pages=833–845 |doi=10.1016/j.joule.2018.03.008 |issn=2542-4785|doi-access=free |bibcode=2018Joule...2..833L }}</ref> In the end, if stabilized, metallic lithium would be able to produce batteries that hold the most charge, while being the lightest.<ref name="cen.acs.org"/> In recent years, researchers have conducted several studies on the use of single wall [[Carbon nanotube|carbon nanotubes]] (SWCNTs) as conductive additives. These SWCNTs help to preserve electron conduction, ensure stable electrochemical reactions, and maintain uniform volume changes during cycling, effectively reducing anode pulverization.<ref>{{cite journal |last1=Park |first1=Gun |last2=Moon |first2=Hyeongyu |last3=Shin |first3=Sunyoung |last4=Lee |first4=Sumin |last5=Lee |first5=Yongju |last6=Choi |first6=Nam-Soon |last7=Hong |first7=Seungbum |date=2023-07-14 |title=Spatially Uniform Lithiation Enabled by Single-Walled Carbon Nanotubes |journal=ACS Energy Letters |language=en |volume=8 |issue=7 |pages=3154–3160 |doi=10.1021/acsenergylett.3c01060 |issn=2380-8195|doi-access=free }}</ref><ref>{{cite journal |last1=Dressler |first1=R. A. |last2=Dahn |first2=J. R. |date=March 2024 |title=Optimization of Si-containing and SiO based Anodes with Single-Walled Carbon Nanotubes for High Energy Density Applications |journal=Journal of the Electrochemical Society |language=en |volume=171 |issue=3 |pages=030520 |doi=10.1149/1945-7111/ad30dc |issn=1945-7111|doi-access=free |bibcode=2024JElS..171c0520D }}</ref>