Reversible Silicon Anodes with Long Cycles by Multifunctional Volumetric Buffer Layers

Establishing a stable, stress-relieving configuration is imperative to achieve a reversible silicon anode for high energy density lithium-ion batteries. Herein, we propose a silicon composite anode (denoted as T-Si@C), which integrates free space and mixed carbon shells doped with rigid TiO₂/Ti₅Si₃ nanoparticles. In this configuration, the free space accommodates the silicon volume fluctuation during battery operation. The carbon shells with embedded TiO₂/Ti₅Si₃ nanoparticles maintain the structural stability of the anode while accelerating the lithium-ion diffusion kinetics and mitigating interfacial side reactions. Based on these advantages, T-Si@C anodes demonstrate an outstanding lithium storage performance with impressive long-term cycling reversibility and good rate capability. Additionally, T-Si@C//LiFePO₄ full cells show superior electrochemical reversibility. This work highlights the importance of rational structural manipulation of silicon anodes and affords fresh insights into achieving advanced silicon anodes with long life.