Vertical Graphene Reinforced SiOC Microspheres for Crack-Resistant Lithium-Ion Battery Anodes

Careful optimization of the structure of silicon-based active materials and enhancement of their electron/ion transport dynamics in the electrode are critical for effectively tackling the challenges of rapid capacity fading and electrode pulverization in silicon-based anodes. Herein, we report a SiOC hybrid microsphere with vertical graphene sheets (VGSs) grown on its surface, synthesized via a one-step facile calcination method. The VGSs, which bridge the SiOC core and electrolyte, not only act as pathways for Li⁺ transport but also mitigate stress concentration at the shell, thereby synergistically enhancing both the crack resistance and transport kinetics of the anode. As a result, the as-prepared SiOC composites exhibit superior electrochemical performance, with notable enhancements in specific capacity and cycling stability. The SiOC anode delivers a high capacity of 550 mAh g^-1 at 1 A g^-1, with 87% capacity retention over 500 cycles. In essence, this study elucidates the entire process from preparation to failure mechanisms, and the innovative strategy for fabricating SiOC composites offers a promising route for high-performance Li-ion battery anodes.