硅基固态电池的界面失效挑战与应对策略

Silicon-based materials are among the most promising anode materials for solid-state batteries owing to their high specific capacity. However, interface failures between silicon-based electrode materials and solid-state electrolytes disrupt ion and electron transport pathways, leading to increased internal impedance, uneven current-density distribution, and eventual degradation of battery capacity and cycle life. This issue presents a major challenge in designing high-energy-density and long-cycle silicon-based solid-state batteries. First, we evaluate the reasons for interface failures between silicon-based materials and solid-state electrolytes, focusing on crystal structures, critical dimensions, and electrochemical sintering. We also discuss the impact of lithium concentration on the electronic conductivity, ionic diffusion coefficient, and Young's modulus of pure silicon materials. Furthermore, we summarize various strategies to address the interface failures, including the application of binders, buffer layers, electrode-material structure design, and particle-size matching between electrode materials and electrolytes. Additionally, we emphasize the potential influence of applying equal and constant stacking pressure on battery performance during the cycling process. This study aims to elucidate the scientific challenges associated with silicon-based material and electrolyte-interface failures in solid-state batteries, resulting in capacity decay and decreased cycle life. Further, this work proposes strategies to address these challenges considering silicon-based material design, electrode material preparation, and electrode-electrolyte matching, thereby guiding further advancements in this field.