SiOx/C anodes with high initial coulombic efficiency through the synergy effect of pre-lithiation and fluoroethylene carbonate for lithium-ion batteries

Abstract SiOx is considered to be a promising anode material for lithium-ion batteries (LIBs) due to the high lithium storage capacity. However, the large initial irreversible capacity loss and intensive volume change during cycling hinder its commercial applications. Prelithiation is an effective and convenient strategy to improve the initial Coulombic efficiency (ICE) of SiOx, while incomplete and unstable SEI on the prelithiated anode still results in rapid capacity decay. Herein, through the synergy effect of chemical pre-lithiation process and fluoroethylene carbonate reduction, a compact and stable LiF-rich SEI layer is in-situ formed on the surface of prelithiated SiOx anode. The modified SiOx anode exhibits a high ICE of 90.7% with good cycling performance. When paired with the commercial LiNi0.6Co0.2Mn0.2O2 (NCM622) cathode, the assemble pre-Li-SiOx/C||NCM622 full cell exhibit a high ICE of 85.7% and stable cycling stability. This work provides a new insight in constructing favorable SEI in pre-lithiation process.