Enabling Improved Electrochemical Performance of Lithium Metal Batteries with Fluorinated SO2 Based Nonflammable Inorganic Electrolyte

Abstract

Lithium metal anodes are one of the most promising candidates to replace conventional graphite anodes and achieve high energy density because of their high theoretical capacity (3,860 mAh g-1) and the low redox potential (-3.04 V versus standard hydrogen electrode). Unfortunately, the poor cycle performance and safety issues, mainly caused by the formation of lithium dendritic growth during battery cycling, hinder their practical applications. Herein, we introduce lithium metal batteries(LMBs) with fluorinated SO2 based inorganic electrolyte, LiAlCl4-xFx-3SO2. The LiAlCl4-xFx-3SO2 electrolyte exhibits nonflammability and high ionic conductivity (about 80 mS cm-1 at room temperature). In addition, we confirm that LiAlCl4-xFx-3SO2 electrolyte shows much improved cycle performance and rate capability than that of LiAlCl4-3SO2 electrolyte. It could be ascribed to the formation of more stable solid electrolyte interphase induced by the existence of AlCl3F- in LiAlCl4-xFx-3SO2. Detailed mechanism of our battery system with fluorinated SO2 based nonflammable inorganic electrolyte will be discussed in the presentation.