Solid-state battery

A solid-state battery is a battery technology that uses solid electrodes and a solid electrolyte, instead of the liquid or polymer gel electrolytes found in lithium-ion or lithium polymer batteries.[1][2]

While solid electrolytes have been first discovered in the 19th century, several drawbacks, such as low energy densities, have prevented widespread application. Developments in the late 20th and early 21st century have caused renewed interest in solid-state battery technologies, especially in the context of electric vehicles, starting in the 2010s.

Materials proposed for use as solid electrolytes in solid-state batteries include ceramics (e.g., oxides, sulfides, phosphates), and solid polymers. Solid-state batteries have found use in pacemakers, RFID and wearable devices. They are potentially safer, with higher energy densities, but at a much higher cost. Challenges to widespread adoption include energy and power density, durability, material costs, sensitivity and stability.[3]


Between 1831 and 1834, Michael Faraday discovered the solid electrolytes silver sulfide and lead(II) fluoride, which laid the foundation for solid-state ionics.[4][5]

By the late 1950s, several electrochemical systems employed solid electrolytes. They used a silver ion, but had some undesirable qualities, including low energy density and cell voltages, and high internal resistance.[6] A new class of solid-state electrolyte, developed by the Oak Ridge National Laboratory, emerged in the 1990s, which was then used to make thin film lithium-ion batteries.[7]

As technology advanced into the new millennium, researchers and companies operating in the automotive and transportation industries experienced revitalized interest in solid-state battery technologies. In 2011, Bolloré launched a fleet of their BlueCar model cars, first in cooperation with carsharing service Autolib, and later released to retail customers. The car was meant to showcase the company's diversity of electric-powered cells in application, and featured a 30 kWh lithium metal polymer (LMP) battery with a polymeric electrolyte, created by dissolving lithium salt in a co-polymer (polyoxyethylene).

In 2012, Toyota soon followed suit and began conducting experimental research into solid-state batteries for applications in the automotive industry in order to remain competitive in the EV market.[8] At the same time, Volkswagen began partnering with small technology companies specializing in the technology.

A series of technological breakthroughs ensued. In 2013, researchers at the University of Colorado Boulder announced the development of a solid-state lithium battery, with a solid composite cathode based on an iron-sulfur chemistry, that promised higher energy capacity compared to already-existing SSBs.[9] And then in 2014, researchers at Ann-Arbor, MI – based startup Sakti3 announced the construction of their own solid-state lithium-ion battery, claiming that it yielded even higher energy density for lower costs;[10] in response, household appliance maker Dyson strategically acquired Sakti3 for $90 million.[11][12]

In 2017, John Goodenough, the co-inventor of Li-ion batteries, unveiled a solid-state battery, using a glass electrolyte and an alkali-metal anode consisting of lithium, sodium or potassium.[13] Later that year, Toyota announced the deepening of its decades-long partnership with Panasonic, including a collaboration on solid-state batteries.[14] Due to its early intensive research and coordinated collaborations with other industry leaders, Toyota holds the most SSB-related patents.[15] However, other car makers independently developing solid-state battery technologies quickly joined a growing list that includes BMW,[16] Honda,[17] Hyundai Motor Company[18] and Nissan.[19] Fisker Inc. has generated a proprietary in-house solution to SSB production for SSB-powered vehicle applications, but the aggressive initial target to bring the EMotion super-sedan to consumer markets for commercialization by 2020 was considerably delayed in favor of conventional EVs that could compete with the Tesla Model Y in 2020.[20] Dyson announced[11] and then abandoned[21] a plan to build an SSB-powered electric car through its Sakti3 assets, though spokeswomen for Dyson reiterated the company's commitment to investing heavily into the technology.[12] Other automotive-related companies, such as Spark plug maker NGK, have retrofitted their business expertise and models to cater to evolving demand for ceramic-based solid state batteries, in the face of perceived obsolescence of the conventional fossil-fuel paradigm.[22]

Major developments continued to unfold into 2018, when Solid Power, spun off from the University of Colorado Boulder research team,[23] received $20 million in funding from Samsung and Hyundai to establish a small manufacturing line that could produce copies of its all-solid-state, rechargeable lithium-metal battery prototype,[24] with a predicted 10 megawatt hours of capacity per year.[25] QuantumScape, another solid-state battery startup that spun out of a collegiate research group (in this case, Stanford University) drew attention that same year, when Volkswagen announced a $100 million investment into the team's research, becoming the largest stakeholder, joined by investor Bill Gates.[26] With the goal to establish a joint production project for mass production of solid-state batteries, Volkswagen endowed QuantumScape with an additional $200 million in June 2020, and QuantumScape IPO'd on the NYSE on November 29th, 2020, as part of a merger with Kensington Capital Acquisition, to raise additional equity capital for the project.[27][28]

Qing Tao started the first Chinese production line of solid-state batteries in 2018 as well, with the initial intention of supplying SSBs for “special equipment and high-end digital products”; however, the company has spoken with several car manufacturers with the intent to potentially expand into the automotive space.[29]

In 2021, Toyota will unveil a prototype electric vehicle powered by solid-state batteries, with further plans to be the first automaker to sell an electric vehicle with solid state batteries.[30] Solid Power anticipates "entering the formal automotive qualification process" in early 2022,[31] and QuantumScape has "scheduled mass production to begin in the second half of 2024".[28] Similarly, Fisker has claimed that its solid-state battery technology should be ready for "automotive-grade production" in 2023.[32]

On Feb 26th, 2021, Fisker announced that based on unforeseen difficulties and perceived insurmountable obstacles, the company has decided to completely drop out of its SSB endeavor. [33]


Solid-state electrolytes candidate materials include ceramics such as lithium orthosilicate,[34] glass[13] and sulfides.[35]The cathodes are lithium based. Variants include LiCoO2, LiNi1/3Co1/3Mn1/3O2, LiMn2O4, and LiNi0.8Co0.15Al0.05O2. The anodes vary more and are affected by the type of electrolyte. Examples include In, GexSi1−x, SnO–B2O3, SnS –P2S5, Li2FeS2, FeS, NiP2, and Li2SiS3.[36]

One promising cathode material is Li-S, which (as part of a solid lithium anode/Li2S cell) has a theoretical specific capacity of 1670 mAh g−1, "ten times larger than the effective value of LiCoO2". Sulfur makes an unsuitable cathode in liquid electrolyte applications because it is soluble in most liquid electrolytes, dramatically decreasing the battery's lifetime. Sulfur is studied in solid state applications.[36] Recently, a ceramic textile was developed that showed promise in a LI-S solid state battery. This textile facilitated ion transmission while also handling sulfur loading, although it did not reach the projected energy density. The result "with a 500-μm-thick electrolyte support and 63% utilization of electrolyte area" was "71 Wh/kg." while the projected energy density was 500 Wh/kg.[37]

Li-O2 also have high theoretical capacity. The main issue with these devices is that the anode must be sealed from ambient atmosphere, while the cathode must be in contact with it.[36]

A Li/LiFePO4 battery shows promise as a solid state application for electric vehicles. A 2010 study presented this material as a safe alternative to rechargeable batteries for EV's that "surpass the USABC-DOE targets".[38]


Solid-state batteries have found potential use in pacemakers, RFID and wearable devices.[39][40]

Electric vehiclesEdit

Hybrid and plug-in electric cars use a variety of battery technologies, including Li-ion, Nickel–metal hydride (NiMH), Lead–acid, and electric double-layer capacitor (or ultracapacitor),[41] led by Li-ion.[42]



Solid-state batteries are traditionally expensive to make[43] and employ manufacturing processes thought to be difficult to scale, requiring expensive vacuum deposition equipment.[7] As a result, costs become prohibitive in consumer-based applications. It was estimated in 2012 that, based on then-current technology, a 20 Ah solid-state battery cell would cost US$100,000, and a high-range electric car would require between 800 and 1,000 of such cells.[7] Likewise, cost has impeded the adoption of solid-state batteries in other areas, such as smartphones.[39]

Temperature and pressure sensitivityEdit

Low temperature operations may be challenging.[43] Solid-state batteries historically had poor performance.[9]

Solid-state batteries with ceramic electrolytes require high pressure to maintain contact with the electrodes.[44] Solid-state batteries with ceramic separators may break from mechanical stress.[7]


Lithium metal dendrite from the anode piercing through the separator and growing towards the cathode.

Solid lithium (Li) metal anodes in solid-state batteries are replacement candidates in lithium-ion batteries for higher energy densities, safety, and faster recharging times. Such anodes tend to suffer from the formation and the growth of Li dendrites.[45]

Dendrites penetrate the separator between the anode and the cathode causing short circuits. This causes overheating, which may result in fires or explosions from thermal runaway.[46] Li dendrites reduce coulombic efficiency.[47]

Dendrites commonly form during electrodeposition[48] during charge and discharge. Li ions combine with electrons at the anode surface as the battery charges - forming a layer of lithium metal.[49] Ideally, the lithium deposition occurs evenly on the anode. However, if the growth is uneven, dendrites form.[50]

Stable solid electrolyte interphase (SEI) was found to be the most effective strategy for inhibiting dendrite growth and increasing cycling performance.[47] Solid-state electrolytes (SSEs) may prevent dendrite growth, although this remains speculative.[46] A 2018 study identified nanoporous ceramic separators that block Li dendrite growth up to critical current densities.[51]


Solid-state battery technology is believed to deliver higher energy densities (2.5x),[52] by enabling lithium metal anodes.

They may avoid the use of dangerous or toxic materials found in commercial batteries, such as organic electrolytes.[53]

Because most liquid electrolytes are flammable and solid electrolytes are nonflammable, solid-state batteries are believed to have lower risk of catching fire. Fewer safety systems are needed, further increasing energy density.[1][53] Recent studies show that heat generation inside is only ~20-30% of conventional batteries with liquid electrolyte under thermal runaway.[54]

Solid-state battery technology is believed to allow for faster charging.[55][56] Higher voltage and longer cycle life is also possible.[53][43]

See alsoEdit


  1. ^ a b Reisch, Marc S. (20 November 2017). "Solid-state batteries inch their way toward commercialization". Chemical & Engineering News. 95 (46): 19–21. doi:10.1021/cen-09546-bus.
  2. ^ Vandervell, Andy (26 September 2017). "What is a solid-state battery? The benefits explained". Wired UK. Retrieved 7 January 2018.
  3. ^ Weppner, Werner (September 2003). "Engineering of solid state ionic devices". International Journal of Ionics. 9 (5–6): 444–464. doi:10.1007/BF02376599. S2CID 108702066. Solid state ionic devices such as high performance batteries...
  4. ^ Funke K (August 2013). "Solid State Ionics: from Michael Faraday to green energy-the European dimension". Science and Technology of Advanced Materials. 14 (4): 043502. Bibcode:2013STAdM..14d3502F. doi:10.1088/1468-6996/14/4/043502. PMC 5090311. PMID 27877585.
  5. ^ Lee, Sehee (2012). "Solid State Cell Chemistries and Designs" (PDF). ARPA-E. Retrieved 7 January 2018.
  6. ^ Owens, Boone B.; Munshi, M. Z. A. (January 1987). "History of Solid State Batteries" (PDF). Defense Technical Information Center. Corrosion Research Center, University of Minnesota. Bibcode:1987umn..rept.....O. Retrieved 7 January 2018.
  7. ^ a b c d Jones, Kevin S.; Rudawski, Nicholas G.; Oladeji, Isaiah; Pitts, Roland; Fox, Richard. "The state of solid-state batteries" (PDF). American Ceramic Society Bulletin. 91 (2).
  8. ^ Greimel, Hans (27 January 2014). "Toyota preps solid-state batteries for '20s". Automotive News. Retrieved 7 January 2018.
  9. ^ a b "Solid-state battery developed at CU-Boulder could double the range of electric cars". University of Colorado Boulder. 18 September 2013. Archived from the original on 7 November 2013. Retrieved 7 January 2018.
  10. ^ Dumaine, Brian (18 September 2014). "Will this battery change everything?". Fortune Magazine. Retrieved 7 January 2018.
  11. ^ a b "Vacuum Tycoon James Dyson To Roll Out An Electric Car By 2020". Forbes. 26 September 2017. Retrieved 7 January 2018.
  12. ^ a b "Dyson walks away from (three) Sakti3 solid-state battery patents: updated". Green Car Reports.
  13. ^ a b "Lithium-Ion Battery Inventor Introduces New Technology for Fast-Charging, Noncombustible Batteries". University of Texas at Austin. 28 February 2017. Retrieved 7 January 2018.
  14. ^ Buckland, Kevin; Sagiike, Hideki (13 December 2017). "Toyota Deepens Panasonic Battery Ties in Electric-Car Rush". Bloomberg Technology. Retrieved 7 January 2018.
  15. ^ Baker, David R (3 April 2019). "Why lithium-ion technology is poised to dominate the energy storage future". Bloomberg. Retrieved 7 April 2019.
  16. ^ "Solid Power, BMW partner to develop next-generation EV batteries". Reuters. 18 December 2017. Retrieved 7 January 2018.
  17. ^ Krok, Andrew (21 December 2017). "Honda hops on solid-state battery bandwagon". Roadshow by CNET. Retrieved 7 January 2018.
  18. ^ Lambert, Fred (6 April 2017). "Hyundai reportedly started pilot production of next-gen solid-state batteries for electric vehicles". Electrek. Retrieved 7 January 2018.
  19. ^ "Honda and Nissan said to be developing next-generation solid-state batteries for electric vehicles". The Japan Times. Kyodo News. 21 December 2017. Retrieved 7 January 2018.
  20. ^ "Fisker solid-state batteries won't arrive until at least 2022". Green Car Reports. Retrieved 2021-01-07.
  21. ^ "Dyson scraps plans for electric car". 2019-10-10. Retrieved 2019-10-10.
  22. ^ Tajitsu, Naomi (21 December 2017). "Bracing for EV shift, NGK Spark Plug ignites all solid-state battery quest". Reuters. Retrieved 7 January 2018.
  23. ^ Danish, Paul (2018-09-12). "Straight out of CU (and Louisville): A battery that could change the world". Boulder Weekly. Retrieved 2020-02-12.
  24. ^ "Solid Power raises $20 million to build all-solid-state batteries — Quartz". Retrieved 2018-09-10.
  25. ^ "Samsung Venture, Hyundai Investing in Battery Producer". Retrieved 2018-09-11.
  26. ^ "Volkswagen becomes latest automaker to invest in solid-state batteries for electric cars". 22 Jun 2018.
  27. ^ Wayland, Michael (2020-09-03). "Bill Gates-backed vehicle battery supplier to go public through SPAC deal". CNBC. Retrieved 2021-01-07.
  28. ^ a b "QuantumScape successfully goes public". Retrieved 2021-01-07.
  29. ^ Lambert, Fred (November 20, 2018). "China starts solid-state battery production, pushing energy density higher".
  30. ^ "Toyota's game-changing solid-state battery en route for 2021 debut". Nikkei Asia. 10 December 2020. Retrieved 11 December 2020.
  31. ^ Power, Solid. "Solid Power's High Energy, Automotive-Scale All Solid-State Batteries Surpass Commercial Lithium-Ion Energy Densities". Retrieved 2021-01-07.
  32. ^ Lambert, Fred (14 November 2017). "Fisker claims solid-state battery 'breakthrough' for electric cars with '500 miles range and 1 min charging'". Electrek. Retrieved 7 January 2018.
  33. ^ O'Kean, Sean (26 February 2021). ""Fisker Inc. has 'completely dropped' solid-state batteries"". The Verge. Retrieved 27 February 2021.
  34. ^ Chandler, David L. (12 July 2017). "Study suggests route to improving rechargeable lithium batteries". Massachusetts Institute of Technology. Researchers have tried to get around these problems by using an electrolyte made out of solid materials, such as some ceramics.
  35. ^ Chandler, David L. (2 February 2017). "Toward all-solid lithium batteries". Massachusetts Institute of Technology. Researchers investigate mechanics of lithium sulfides, which show promise as solid electrolytes.
  36. ^ a b c Takada, Kazunori (2013-02-01). "Progress and prospective of solid-state lithium batteries". Acta Materialia. The Diamond Jubilee Issue. 61 (3): 759–770. doi:10.1016/j.actamat.2012.10.034. ISSN 1359-6454.
  37. ^ Gong, Yunhui; Fu, Kun; Xu, Shaomao; Dai, Jiaqi; Hamann, Tanner R.; Zhang, Lei; Hitz, Gregory T.; Fu, Zhezhen; Ma, Zhaohui; McOwen, Dennis W.; Han, Xiaogang (2018-07-01). "Lithium-ion conductive ceramic textile: A new architecture for flexible solid-state lithium metal batteries". Materials Today. 21 (6): 594–601. doi:10.1016/j.mattod.2018.01.001. ISSN 1369-7021. OSTI 1538573.
  38. ^ Damen, L.; Hassoun, J.; Mastragostino, M.; Scrosati, B. (2010-10-01). "Solid-state, rechargeable Li/LiFePO4 polymer battery for electric vehicle application". Journal of Power Sources. 195 (19): 6902–6904. Bibcode:2010JPS...195.6902D. doi:10.1016/j.jpowsour.2010.03.089. ISSN 0378-7753.
  39. ^ a b Carlon, Kris (24 October 2016). "The battery technology that could put an end to battery fires". Android Authority. Retrieved 7 January 2018.
  40. ^ "Will solid-state batteries power us all?". The Economist. 16 October 2017.
  41. ^ "Batteries for Hybrid and Plug-In Electric Vehicles". Alternative Fuels Data Center. Retrieved 7 January 2018.
  42. ^ "Energy Storage". National Renewable Energy Laboratory. Retrieved 7 January 2018. Many automakers have adopted lithium-ion (Li-ion) batteries as the preferred EDV energy storage option, capable of delivering the required energy and power density in a relatively small, lightweight package.
  43. ^ a b c Jones, Kevin S. "State of Solid-State Batteries" (PDF). Retrieved 7 January 2018.
  44. ^ "New hybrid electrolyte for solid-state lithium batteries". 21 December 2015. Retrieved 7 January 2018.
  45. ^ Wood, Kevin N.; Kazyak, Eric; Chadwick, Alexander F.; Chen, Kuan-Hung; Zhang, Ji-Guang; Thornton, Katsuyo; Dasgupta, Neil P. (2016-10-14). "Dendrites and Pits: Untangling the Complex Behavior of Lithium Metal Anodes through Operando Video Microscopy". ACS Central Science. 2 (11): 790–801. doi:10.1021/acscentsci.6b00260. PMC 5126712. PMID 27924307.
  46. ^ a b Jiang, Hanqing; Tang, Ming; Duan, Huigao; Wang, Fan; Yang, Haokai; Xu, Wenwen; Hong, Liang; Zeng, Wei; Wang, Xu (March 2018). "Stress-driven lithium dendrite growth mechanism and dendrite mitigation by electroplating on soft substrates". Nature Energy. 3 (3): 227–235. Bibcode:2018NatEn...3..227W. doi:10.1038/s41560-018-0104-5. ISSN 2058-7546. S2CID 139981784.
  47. ^ a b Cheng, Xin-Bing; Zhang (17 November 2015). "A Review of Solid Electrolyte Interphases on Lithium Metal Anode". Advanced Science. 3 (3): 1500213. doi:10.1002/advs.201500213. PMC 5063117. PMID 27774393.
  48. ^ Zhang, Ji-Guang; Xu, Wu; Henderson, Wesley A. (2016-10-07), "Application of Lithium Metal Anodes", Lithium Metal Anodes and Rechargeable Lithium Metal Batteries, Springer International Publishing, pp. 153–188, doi:10.1007/978-3-319-44054-5_4, ISBN 9783319440538
  49. ^ Harry, Katherine Joann (2016-05-01). "Lithium dendrite growth through solid polymer electrolyte membranes". doi:10.2172/1481923. OSTI 1481923. Cite journal requires |journal= (help)
  50. ^ Newman, John; Monroe, Charles (2003-10-01). "Dendrite Growth in Lithium/Polymer Systems A Propagation Model for Liquid Electrolytes under Galvanostatic Conditions". Journal of the Electrochemical Society. 150 (10): A1377–A1384. doi:10.1149/1.1606686. ISSN 0013-4651.
  51. ^ Bazant, Martin Z.; Brushett, Fikile R.; Li, Ju; Su, Liang; Kushima, Akihiro; Wang, Miao; Guo, Jinzhao; Bai, Peng (2018-11-21). "Interactions between Lithium Growths and Nanoporous Ceramic Separators". Joule. 2 (11): 2434–2449. doi:10.1016/j.joule.2018.08.018. ISSN 2542-4785.
  52. ^ Dudney, Nancy J; West, William C; Nanda, Jagjit, eds. (2015). Handbook of Solid State Batteries. Materials and Energy. 6 (2nd ed.). World Scientific Publishing Co. Pte. doi:10.1142/9487. hdl:10023/9281. ISBN 978-981-4651-89-9.
  53. ^ a b c Bullis, Kevin (19 April 2011). "Solid-State Batteries - High-energy cells for cheaper electric cars". MIT Technology Review. Retrieved 7 January 2018.
  54. ^ Inoue, Takao; Mukai, Kazuhiko (2017-01-18). "Are All-Solid-State Lithium-Ion Batteries Really Safe?–Verification by Differential Scanning Calorimetry with an All-Inclusive Microcell". ACS Applied Materials & Interfaces. 9 (2): 1507–1515. doi:10.1021/acsami.6b13224. ISSN 1944-8244. PMID 28001045.
  55. ^ Eisenstein, Paul A. (1 January 2018). "From cellphones to cars, these batteries could cut the cord forever". NBC News. Retrieved 7 January 2018.
  56. ^ Limer, Eric (25 July 2017). "Toyota Working on Electric Cars That Charge in Minutes for 2022". Popular Mechanics. Retrieved 7 January 2018.

External linksEdit