An Effective Strategy on Synthesizing a Stable SiO_x-Based Anode for High Density Lithium-Ion Batteries

Silicon oxides (SiO_x) have received extensive attention as a promising anode candidate for next-generation lithium-ion batteries (LIBs). However, their commercial applications have been seriously hindered by low conductivity, large volume expansion, and unstable solid-electrolyte interface (SEI) layer, which result in low initial coulombic efficiency, poor rate performance, and short cycling lifespan. In this work, we demonstrated a simple way to prepare a series of SiO_x materials with lithium fluoride (LiF) modified. When the mass ratio of SiO_x and LiF equaled 1 : 0.15, the long-term cycling capacity retention could be greatly improved from 30.1 % to 76.5 % after 300 cycles. The result was primarily because of the enhancement of electrons and Li⁺-ions transport and the stability of the SEI layer due to LiF addition. However, excess LiF addition could hinder the diffusion of Li⁺-ions. This study presented the great potential of LiF modified on SiO_x anode materials for LIBs.