Enhanced electrochemical performance of Si/C electrode through surface modification using SrF2 particle

The silicon-based material exhibits a high theoretical specific capacity and is one of the best anode for the next generation of advanced lithium-ion batteries (LIBs). However, it is difficult for the silicon-based anode to form a stable solid-state interphase (SEI) during Li alloy/de-alloy process due to the large volume change (up to 300%) between silicon and Li 4.4 Si, which seriously limits the cycle life of the LIBs. Herein, we use strontium fluoride (SrF 2 ) particle to coat the silicon-carbon (Si/C) electrode (SrF 2 @Si/C) to help forming a stable and high mechanical strength SEI by spontaneously embedding the SrF 2 particle into SEI. Meanwhile the formed SEI can inhibit the volume expansion of the silicon-carbon anode during the cycle. The electrochemical test results show that the cycle performance and the ionic conductivity of the SrF 2 @Si/C anode has been significantly improved. The X-ray photoelectron spectroscopy (XPS) analysis reveals that there are fewer electrolyte decomposition products formed on the surface of the SrF 2 @Si/C anode. This study provides a facile approach to overcome the problems of Si/C electrode during the electrochemical cycling, which will be beneficial to the industrial application of silicon-based anode materials.