碳酸乙烯酯
材料科学
电化学
电解质
碳酸二乙酯
电池(电)
溶剂化
化学工程
电化学窗口
金属
碳酸盐
无机化学
电极
离子
物理化学
离子电导率
功率(物理)
热力学
冶金
化学
物理
有机化学
工程类
作者
Wenna Zhang,Tong Yang,Xiaobin Liao,Yi Song,Yan Zhao
标识
DOI:10.1016/j.ensm.2023.02.027
摘要
Highly fluorinated electrolytes are appealing to directly improve the evolution of Li+ solvation sheath and arouse high-quality solid-electrolyte interphases (SEIs) for Li metal batteries (LMBs) with stable cycling. Herein, the effect of fluorinated engineering-based electrolytes on Li+ solvation structure and the relevant electrochemical performance were systematically investigated. By a selective combination of the ethylene carbonate (EC), diethyl carbonate (DEC), fluoroethylene carbonate (FEC), and ethyl (2,2,2-trifluoroethyl) carbonate (ETFEC), it is found that all-fluorinated electrolyte containing FEC and ETFEC directly optimizes the Li+ solvation environments where coordination numbers of Li+ decreases from 3.75 in none-fluorinated electrolyte to 3.02 in all-fluorinated electrolyte according to molecular dynamic (MD) simulations. Impressively, fast Li+ desolvation in all-fluorinated electrolyte induced stable LiF-rich interface accompanied by the inhibition of Li dendrites, and thus Li||Cu asymmetrical cells achieved high CE of average 98.3% at 0.5 mA cm–2 as well as superior cycling stability. Encouragingly, the Li||NCM811 cells even retained the initial capacity of 72.3% with an average CE of 99.8% at high voltage (up to 4.6 V) after 225 cycles. This work offers a Li+ solvation sheath-directly tuned strategy to construct the ideal interface chemistry for high-performance LMBs.
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