Constructing Si/6H-SiC Heterostructure As a High-Performance Anode for Boosting Lithium-Ion Storage
Peng Zhou, Peng Xiao, Fulu Chu, Wenchao Chen, Yang Li, Feixiang Wu
Abstract
Silicon (Si) anodes offer significant potential due to their high capacity. However, their drastic volume change limits their utility, resulting in a shorter cycling life. In this paper, microsilicon particles and 6H-SiC particles were ball-milled and subsequently coated a layer of amorphous carbon, yielding Si/SiC@C composites. Computational and experimental results reveal that this heterostructure formed between Si and 6H-SiC enhances the electronic conductivity of the Si/SiC@C composites dramatically, as well as the Li ion diffusion rate. Thereby, the Si/6H-SiC heterostructure increases capacity and enhances the rate capability of the Si-based anode. Significantly, the conductivity of Si/SiC@C composites surpasses that of Si@C composites by a factor of around 330. Furthermore, tough, evenly distributed, and electrochemically inert 6H-SiC serves as a rigid framework. By reducing the expansion rate of Si-based anodes and mitigating mechanical stress during cycles, this improves the cycling stability. Additionally, the Si/SiC@C anodes demonstrate superior cycle performance (814.6 mAh g –1 at 1 A g –1 after 400 cycles with capacity retention of 88.0%) and excellent rate capability (762 mAh g –1 at 5 A g –1 ).