N, P, S co-doped carbon encapsulating silicon formed yolk-shell Si/C composite for high-performance lithium-ion batteries

Abstract

The silicon (Si) anode boasts an exceptionally high theoretical capacity (4200 mAh g⁻¹), making it an attractive candidate for advanced lithium-ion batteries (LIBs). However, its practical application is limited by poor electrical conductivity and disastrous volume expansion. In this work, we have successfully synthesized a yolk-shell composite material (Si@H-CoNPSC) consisting of N, P, S co-doped carbon encapsulated silicon nanoparticles (SiNPs) via a self-template method based on the Kirkendall effect. The Si@H-CoNPSC anode exhibits excellent electrochemical performance, after 300 cycles, keeping a specific capacity of 872.8 mAh g⁻¹ at 1 A g⁻¹. Additionally, after 150 cycles, it retains 1305.8 mAh g⁻¹ at 0.5 A g⁻¹, with a capacity retention of 91.1 %. These outstanding results are mainly due to the co-doped hollow carbon shell, which improves the anode’s conductivity and reduces volume changes during cycling. This study provides new insights for the designing of silicon-carbon anode structures for high-performance LIBs.