Failure Mechanisms and Modification Strategies of Silicon-Carbon and Derivative Anodes for Lithium-Ion Batteries

Lithium-ion batteries (LIBs) with high energy density, as emerging energy-storage systems, rely on high-capacity electrode to drive the energy transition. Silicon (Si) has been considered as a promising alternative to graphite anodes due to its exceptional theoretical capacity, exhibiting enormous potential to meet the demand for high-energy-density energy storage. However, Si anodes are constrained by substantial volume expansion during lithiation, unstable solid electrolyte interphase (SEI), and poor electrical conductivity. To address these challenges, researchers have integrated the advantages of different materials to develop silicon/carbon (Si@C) composites as LIBs anodes, which offer a unique balance between structural toughness and electrochemical performance. Nevertheless, Si@C materials still face unsatisfactory structural stability, interfacial compatibility, and electrochemical kinetics during electrochemical cycling. Combined with recent research advances, this review summarizes and comparatively analyzes the mainstream preparation methods of Si@C composites. Based on the lithium storage mechanism of silicon, the multi-dimensional failure mechanisms of Si@C anodes are systematically clarified. Focusing on the key bottlenecks, including structural degradation, interfacial instability, inferior intrinsic conductivity, and industrial application limitations, current modification strategies are comprehensively reviewed and critically compared. Furthermore, the cutting-edge development trends of Si@C anodes are prospected, providing systematic theoretical support and technical guidance for future mechanism exploration, process optimization, and large-scale industrial applications.