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

doi:10.1002/adma.202001741

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

Adv Mater. 2020 Jul;32(26):e2001741. doi: 10.1002/adma.202001741. Epub 2020 May 25.

Authors

Hao Sun¹, Guanzhou Zhu¹, Yuanmin Zhu², Meng-Chang Lin³, Hui Chen³, Yuan-Yao Li^{1

4}, Wei Hsuan Hung^{1

5}, Bo Zhou⁶, Xi Wang⁷, Yunxiang Bai¹, Meng Gu², Cheng-Liang Huang⁴, Hung-Chun Tai⁴, Xintong Xu¹, Michael Angell¹, Jing-Jong Shyue⁸, Hongjie Dai¹

Affiliations

¹ Department of Chemistry, Stanford University, Stanford, CA, 94305, USA.
² Department of Materials Science and Engineering Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen, Guangdong, 518055, China.
³ College of Electrical Engineering and Automation, Shandong University of Science and Technology, Qingdao, 266590, China.
⁴ Department of Chemical Engineering, National Chung Cheng University, Chiayi, 62102, Taiwan.
⁵ Institute of Materials Science and Engineering, National Central University, Taoyuan, 32001, Taiwan.
⁶ Chemistry and Chemical Engineering Guangdong Laboratory, Shantou, 515031, China.
⁷ Key Laboratory of Luminescence and Optical Information Ministry of Education, Department of Physics, School of Science, Beijing Jiaotong University, Beijing, 100044, China.
⁸ Research Center for Applied Sciences, Academia Sinica, Taipei, 11529, Taiwan.

PMID: 32449260
DOI: 10.1002/adma.202001741

Abstract

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 (LiNi_0.8 Co_0.1 Mn_0.1 O₂ , 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.

Keywords: high-energy-density batteries; ionic-liquid electrolytes; lithium metal batteries.