Preparation of Buffered Nano-Submicron Hierarchical Structure Hollow SiO_x@C Anodes for Lithium-Ion Battery Materials with Carboxymethyl Chitosan

Silicon-based materials are among the most promising anode materials for next-generation lithium-ion batteries. However, the volume expansion and poor conductivity of silicon-based materials during the charge and discharge process seriously hinder their practical application in the field of anodes. Here, we choose carboxymethyl chitosan (CMCS) as the carbon source coating and binding on the surface of nano silicon and hollow silicon dioxide (H−SiO₂) to form a hierarchical buffered structure of nano-hollow SiO_x@C. The hollow H−SiO₂ can alleviate the volume expansion of nano silicon during the lithiation process under continuous cycling. Meanwhile, the carbon layer carbonized by CMCS containing N-doping further regulates the silicon's expansion and improves the conductivity of the active materials. The as-. prepared SiO_x@C material exhibits an initial discharge capacity of 985.4 mAh g⁻¹ with the decay rate of 0.27 % per cycle in 150 cycles under the current density of 0.2 A g⁻¹. It is proved that the hierarchical buffer structure nano-hollow SiO_x@C anode material has practical application potential.