High-Safety and High-Energy-Density Lithium Metal Batteries in a Novel Ionic-Liquid Electrolyte

Hao Sun, Guanzhou Zhu, Yuanmin Zhu, Meng Chang Lin, Hui Chen, Yuan Yao Li, Wei Hsuan Hung, Bo Zhou, Xi Wang, Yunxiang Bai, Meng Gu, Cheng Liang Huang, Hung Chun Tai, Xintong Xu, Michael Angell, Jing Jong Shyue, Hongjie Dai

Research output: Contribution to journalArticlepeer-review

106 Citations (Scopus)


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 (LiCoO2) and lithium nickel cobalt manganese oxide (LiNi0.8Co0.1Mn0.1O2, 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.

Original languageEnglish
Article number2001741
JournalAdvanced Materials
Issue number26
Publication statusPublished - Jul 1 2020
Externally publishedYes


  • high-energy-density batteries
  • ionic-liquid electrolytes
  • lithium metal batteries

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering


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