Silicon Nitride‐Enabled Mechanical Reinforcement and Interfacial Catalysis Toward Highly Stable Silicon‐Based Anodes

Silicon suboxide (SiO x ) is a promising anode material for next‐generation high‐energy‐density lithium‐ion batteries due to its high theoretical capacity. However, pronounced volume expansion during lithiation leads to structural failure and interfacial instability, severely limiting its practical application. Conventional approaches, such as carbon coating or nanostructuring, mainly provide passive buffering and fail to fundamentally mitigate mechanical degradation. Herein, a synergistic modification strategy integrating mechanical reinforcement and interfacial catalysis is proposed for silicon‐based anodes. High‐performance ceramic silicon nitride (Si 3 N 4 ) is incorporated into SiO x via high‐energy ball milling (HEBM), forming a SiO x ‐Si 3 N 4 composite anode (denoted as SiO x @Si 3 N 4 ‐HEBM). The introduced Si 3 N 4 establishes a rigid supporting structure that suppresses volume expansion and particle agglomeration during lithiation, thereby alleviating mechanical stress. In addition, Si 3 N 4 catalyzes the in situ formation of a Li 3 N‐rich solid electrolyte interphase (SEI), enhancing interfacial ion‐transport kinetics. At a reversible capacity of 1350 mAh g −1 , the capacity retention after 100 cycles at 0.5 C is improved from 38.89% to 64.36%, accompanied by enhanced rate capability and significantly reduced interfacial impedance. This work offers an effective strategy for improving the cycling stability of silicon‐based anodes through coupled mechanical and interfacial regulation, highlighting its potential for practical applications.