Low concentration electrolyte with non-solvating cosolvent enabling high-voltage lithium metal batteries

Zhipeng Jiang; Ziqi Zeng; Han Zhang; Li Yang; Wei Hu; Xinmiao Liang; Jiwen Feng; Chuang Yu; Shijie Cheng; Jia Xie

doi:10.1016/j.isci.2021.103490

Low concentration electrolyte with non-solvating cosolvent enabling high-voltage lithium metal batteries

iScience. 2021 Dec 1;25(1):103490. doi: 10.1016/j.isci.2021.103490. eCollection 2022 Jan 21.

Authors

Zhipeng Jiang^{1

2}, Ziqi Zeng¹, Han Zhang^{1

2}, Li Yang³, Wei Hu¹, Xinmiao Liang³, Jiwen Feng³, Chuang Yu¹, Shijie Cheng¹, Jia Xie¹

Affiliations

¹ State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, P. R. China.
² State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
³ State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, P. R. China.

Abstract

Developing low cost, yet high-voltage electrolyte is significant to improve the energy density and practicability of lithium metal batteries (LMBs). Low concentration electrolyte has significant merits in terms of cost and viscosity; however, their poor compatibility with high-voltage LMBs hinders its applications. Here, we develop a diluted low concentration electrolyte by replacing solvating cosolvent with a non-solvating cosolvent to facilitate the interaction between BF₄ ^- and Li⁺, resulting in optimized interfacial chemistry and suppressed side reaction. Thus, the high-loading Li-LiCoO₂ full cells (20.4 mg cm^-2) deliver outstanding cycling stability and rate performance at a cutoff voltage of 4.6 V. More impressively, a Li-LiCoO₂ pouch cell achieves an energy density of more than 400 Wh kg^-1 under practical conditions with thin Li (50 μm) and lean electrolyte (2.7 g Ah^-1). This work provides a rational approach to design a low concentration electrolyte, which can be extended to other high voltage battery systems.

Keywords: Electrochemistry; Energy storage; Materials science.