A sandwich-like silicon–carbon composite prepared by surface-polymerization for rapid lithium-ion storage

Silicon-based materials are showing appealing potentials for electrical energy storage because of their unparalleled theoretical energy density. In this work, a rapid and efficient surface-polymerization processing has been developed to obtain a sandwich-like silicon-carbon composite structure for fast lithium storage. The anchored silicon particles are connected with a low diffusion tortuosity in the designed structure that facilitates the electron transport throughout the electrode and enhances the response rate under high current density. Electrochemical measurements demonstrate that the silicon-carbon composite electrode exhibits a high capacity for lithium storage. It shows a reversible capacity of 1990 mA h g−1 at 0.5 C after 100 cycles and also has an excellent capacity retention property (only −0.062% capacity reduction per cycle) in long-term cycling at 1 C. Furthermore, it can deliver a high reversible specific capacity of 1170 mA h g−1 even at 4 C. [Display omitted] •Si particles were coated and connected in a conductive carbon network by surface polymerization.•The sandwich-like structure is beneficial for fast-electrochemical response.•The composite electrode displays a high reversible specific capacity of 1170 mA h g−1 even at 4 C.•The electrode shows an excellent cycling stability (−0.062% capacity fade per cycle).