Cu₃Si-Modified Silicon Nanoparticles Encapsulated within SiO_x and Hollow Carbon for Lithium-Ion Battery Anodes

Abstract

Silicon (Si), a promising anode material for lithium-ion batteries, usually suffers from low capacity retention and poor rate performance due to its huge volume change issue and low electronic conductivity. The synergistic effect brought by the composite of carbon, metal silicide, and silicon is proven to be an effective measure to enhance the performance of silicon-based anodes. Herein, Cu3Si-modified silicon nanoparticles (SiNPs) encapsulated within SiO x and hollow carbon shell (M-Si@H-C) are designed and constructed by an electroless deposition and pyrolysis process, which delivers high specific capacity (1150 mAh g–1 at 0.21 A g–1 and 450 mAh g–1 at 8.4 A g–1) and long cycling stability (86.3% capacity retention after 200 cycles at 1 A g–1). The nanostructure and formation mechanism of the M-Si@H-C is elucidated by employing X-ray diffraction and transmission electron microscopy techniques. The enhancement to the lithium storage performance of the nanostructure is clarified on the basis of the microstructure investigation and electrochemical determination.