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High‐Safety and High‐Energy‐Density Lithium Metal Batteries in a Novel Ionic‐Liquid Electrolyte
Author(s) -
Sun Hao,
Zhu Guanzhou,
Zhu Yuanmin,
Lin MengChang,
Chen Hui,
Li YuanYao,
Hung Wei Hsuan,
Zhou Bo,
Wang Xi,
Bai Yunxiang,
Gu Meng,
Huang ChengLiang,
Tai HungChun,
Xu Xintong,
Angell Michael,
Shyue JingJong,
Dai Hongjie
Publication year - 2020
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.202001741
Subject(s) - electrolyte , materials science , ionic liquid , passivation , electrochemistry , cathode , lithium (medication) , faraday efficiency , lithium cobalt oxide , inorganic chemistry , oxide , lithium vanadium phosphate battery , chemical engineering , anode , ionic bonding , cobalt , cobalt oxide , electrode , battery (electricity) , ion , nanotechnology , lithium ion battery , chemistry , organic chemistry , metallurgy , catalysis , layer (electronics) , endocrinology , engineering , power (physics) , quantum mechanics , medicine , physics
Rechargeable lithium metal batteries are next generation energy storage devices with high energy density, but face challenges in achieving high energy density, high safety, and long cycle life. Here, lithium metal batteries in a novel nonflammable ionic‐liquid (IL) electrolyte composed of 1‐ethyl‐3‐methylimidazolium (EMIm) cations and high‐concentration bis(fluorosulfonyl)imide (FSI) anions, with sodium bis(trifluoromethanesulfonyl)imide (NaTFSI) as a key additive are reported. The Na ion participates in the formation of hybrid passivation interphases and contributes to dendrite‐free Li deposition and reversible cathode electrochemistry. The electrolyte of low viscosity allows practically useful cathode mass loading up to ≈16 mg cm −2 . Li anodes paired with lithium cobalt oxide (LiCoO 2 ) and lithium nickel cobalt manganese oxide (LiNi 0.8 Co 0.1 Mn 0.1 O 2 , NCM 811) cathodes exhibit 99.6–99.9% Coulombic efficiencies, high discharge voltages up to 4.4 V, high specific capacity and energy density up to ≈199 mAh g −1 and ≈765 Wh kg −1 respectively, with impressive cycling performances over up to 1200 cycles. Highly stable passivation interphases formed on both electrodes in the novel IL electrolyte are the key to highly reversible lithium metal batteries, especially for Li–NMC 811 full batteries.