In Situ Deposition of SiO x /C on Graphite with Prelithiation as an Anode for Lithium-Ion Batteries

Abstract Unsaturated silicon oxide (SiOx) as one of the anode materials for lithium-ion batteries (LIBs) shows relatively high specific capacity, but its overall electrochemical performances remain to be improved. Herein, a facile synthetic approach is developed to deposit SiOx and amorphous carbon on spherical graphite particles getting core–shell structured graphite@SiOx/C (SG@SiOx/C) composites via tetraethyl orthosilicate and ascorbic acid as precursors. The homogeneous and dense SiOx/C layer can improve the structural integrity of the SG@SiOx/C anodes and afford the composites with manifest specific capacity for Li+ storage. To improve the initial Coulombic efficiency (ICE), the SG@SiOx/C composites are further chemically prelithiated. The prelithiated SG@SiOx/C exhibits an initial lithiation/delithiation capacity of 632.6/629.4 mAh g–1 with a remarkable ICE of 99.5%. The reversible specific capacity can remain at 390.5 mAh g–1 after 1000 cycles at a current density of 1C. This work offers technical guidance on how to synthesize high-performance graphite@SiOx composites, providing a pathway to high-energy-density LIBs.