Pre-Lithiated Silicon-Based Composite Anode for High-Performance All-Solid-State Batteries

Silicon is widely recognized as a promising anode material for all-solid-state batteries (ASSBs) due to exceptional specific capacity, abundant availability, and environmental sustainability. However, the considerable volume expansion and particle fragmentation of Si during cycling lead to significant performance degradation, limiting its practical application. Herein, the development of a pre-lithiated Si-based composite anode (c-Li₁Si) is presented, designed to address the key challenges faced by Si-based anodes, namely severe volume changes and low electrochemical stability. The c-Li₁Si anodes are prepared by incorporating Li₁Si powders with Li₆PS₅Cl (LPSCl) sulfide solid electrolyte (SSE), forming a dense structure that enhances conductivity and mitigates structural degradation. The ASSBs with c-Li₁Si-60 anode exhibit outstanding electrochemical performance, including excellent rate capability and capacity retention of 84.4% after 1000 cycles at 1 C and exceptional performance even at low anode-to-cathode capacity ratios (N/P ratio) of 1.68. EIS and pressure measurements reveal improved reaction kinetics and reduced volume expansion. X-ray micro-CT and SEM further confirmed the introduction of LPSCl effectively alleviated volume changes and maintained electrode structural integrity, contributing to enhanced electrochemical performance. These results underscore the potential of the c-Li₁Si anode to overcome the intrinsic limitations of Si-based anodes, offering a promising pathway toward high-energy-density ASSBs.