A study on the electrochemical properties of silicon/carbon composite for lithium-ion battery

Silicon (Si) is a promising anode material for academic research and industrial applications to improve the performance of lithium-ion batteries (LIBs). However, the practical application of Si anodes suffers from low ionic, electric conductivity, pulverization, massive volume expansion, and fast capacity fading. This work synthesized an ordered mesoporous carbon-supported Si using SBA-15 nanorods (Santa Barbara amorphous, SiO₂) as a template. The Si@CMK-5 composite is prepared by a simple calcination method. The Si@CMK-5 composite exhibited a high specific capacity of 1900.8 mAhg⁻¹ after 100 cycles at a 0.5C-rate. This outstanding performance is ascribed to the mesoporous structure of SBA-15 and carbon forming a mesoporous carbon framework, which can increase the composite's constancy and conductivity. The oxygen defects formed after magnesiothermic reduction can efficiently reduce the volume changes of the Si and shorten the diffusion path of Li⁺ during cycling. The present work shows a novel approach for constructing high-performance LIBs using a simple experimental process.