Novel Si@C/P anode materials with improved cyclability and rate capacity for lithium-ion batteries

Abstract

As one of the most promising electrode materials for lithium-ion batteries, silicon offers a high theoretical capacity, but it has been greatly limited by a volume expansion effect and the formation of unstable solid–electrolyte interface (SEI) film. Herein, Si@C/P nanoparticles with excellent electrochemical properties were prepared simply by sol-gel method and carbonization process. For lithium-ion batteries, phosphorus-doped phenol formaldehyde resin was used as carbon source for the first time, and phosphorus was successfully doped into carbon skeleton. The synergistic effect of carbon layer and phosphorus doping limits the volume expansion of silicon, and improves the diffusion rate of Li+. The Si@C/P anode exhibits a high initial Coulombic efficiency (ICE) of 84.4% and a specific capacity of 1873 mAh g−1 at 1 A g−1 after 100 cycles. The material shows a good rate performance, the average specific capacity reaches 1422.3 mAh g−1 even at a high current density of 4 A g−1, demonstrating a bright perspective.