Prelithiated Surface Oxide Layer Enabled High-Performance Si Anode for Lithium Storage

SiO x coating is an effective strategy to prolong the cycling stability of Si-based anodes due to the robust interaction between Si and the SiO x layer. However, the SiO x layer-protected Si anode is limited by the relatively low initial Coulombic efficiency and sluggish Li + diffusion ability induced by the SiO x layer. Herein, we present the preparation of selectively prelithiated Si@SiO x (Si@Li 2 SiO 3 ) anode by using a facile strategy to resolve the above issues. As the anode for lithium ion batteries, Si@Li 2 SiO 3 exhibits a high initial Coulombic efficiency (ICE) of 89.1%, an excellent rate performance (959 mA h g –1 at 30 A g –1 ), and a superior capacity retention (3215 mA h g –1 ). The full cell with LiFePO 4 cathode and Si@Li 2 SiO 3 anodes is successfully assembled, disclosing a high ICE of 91.1% and excellent long cycling stability. The superior electrochemical performance of Si@Li 2 SiO 3 can be attributed to the coating layer, which can strengthen the integrity of the electrode, decrease irreversible reactions, and provide efficient Li + diffusion channels.