Achieving a Double Advantage through Design of TiO2/C Interlaced Coating for Si Anode

Abstract Multifunctional coating strategy shows promising prospective in advancing Si‐based anodes towards practical applications in Li‐ion batteries. Dual coating of amorphous carbon and TiO 2 shows demonstrable advantages owing to high elasticity of amorphous carbon and mechanical toughness of TiO 2 . However, for past design of Si@C@TiO 2 composite electrode, wherein C and TiO 2 are configured layer‐by‐layer, a long‐standing problem exists as that a thin TiO 2 coating is insufficient to stabilize the electrode's architecture while a thick one prevents the core active material of Si far from fully electrochemically utilization due to the too strong structural constraint effect. Herein, it presents that a facial heat treatment of Si@C@TiO 2 with thick enough TiO 2 can readily avert the problem. Such a strategy promotes the capacity utilization rate from 39% to 61% for the initial cycle and from 43% to 85% after 200 cycles. Model structure of C/TiO 2 multilayer films is employed to reveal the role of the heat treatment. It finds that the heat treatment can transform a layer‐by‐layer structure of C@TiO 2 into an interlaced structure of C/TiO 2 which exhibits a dual advantage in withstanding mechanical strain and simultaneously promoting Li‐ion storage and electron/Li‐ion transport.