Silicon-carbon anodes for solid‑state batteries: Challenges, optimization strategies, and future perspectives

Abstract

Developing safe, high‑energy‑density energy storage systems is a central goal in electrochemistry. Silicon (Si) delivers a high theoretical specific capacity of 4200 mAh g-1, yet it suffers from severe volume expansion and interfacial degradation. Solid-state electrolytes (SSEs) can exert mechanical confinement and enable the formation of self-limited interfaces, rendering silicon-carbon (Si-C)/SSEs composite a highly promising anode system. This paper first analyzes the failure mechanisms in liquid-electrolyte systems, followed by an elaboration on the distinctive merits of Si-C-based solid-state anodes. Meanwhile, it identifies the core challenges confronting this system, including rigid interfacial contact, dynamic stress, and process compatibility issues. Recent research advances are reviewed from three critical perspectives: intrinsic material modification, interface engineering, and fabrication process optimization, covering diverse modification strategies at both the material and electrode levels. Finally, future research directions are prospected, with emphases on integrated material-device design, advanced in-situ characterization techniques, and artificial intelligence-empowered research and development, aiming to accelerate the practical deployment of low-voltage, high-energy-density solid-state batteries.