Novel core–shell structured Si/S-doped-carbon composite with buffering voids as high performance anode for Li-ion batteries

Abstract

A novel core–shell structured Si/S-doped-carbon composite with buffering voids (Si/v-SC), was prepared by a facile hydrothermal method using glucose as carbon source and simultaneously chemical polymerization of 3,4-ethylenedioxythiophene (EDOT) in the presence of Si@SiO₂ nanoparticles, and followed by carbonization and removal of the SiO₂ layer. The results showed that the Si nanoparticles were embedded in the S-doped-carbon buffer space to form a core–shell structure. Compared to the Si/carbon composite (Si/v-C) without S-doping in carbon layer, the Si/v-SC composite electrode showed improved cycling and rate performance, exhibiting a reversible capacity of 664 mA h g⁻¹ over 300 cycles at the current of 0.4 A g⁻¹ and a high capacity of 537 mA h g⁻¹ even at 10 A g⁻¹. The effects of S-doping on the properties of carbon material were further investigated. XRD and Raman test revealed that the S-doping increased the interspace of carbon crystal face, and improved the amorphous structure of carbon and thus the initial coulombic efficiency.