Vanadium-Tailored Silicon Composite with Furthered Ion Diffusion Behaviors for Longevity Lithium-Ion Storage
Hang Luo, Xuemei Zhang, Ziyang Wang, Luxi Zhang, Changhaoyue Xu, Sizhe Huang, Wei Pan, Wenlong Cai, Yun Zhang
Abstract
As one of the promising anode materials, silicon has attracted much attention due to its high theoretical specific capacity (∼3579 mAh g –1 ) and suitable lithium alloying voltage (0.1–0.4 V). Nevertheless, the enormous volume expansion (∼300%) in the process of lithium alloying has a great negative effect on its cyclic stability, which seriously restricts the large-scale industrial preparation of silicon anodes. Herein, we design a facile synthesis strategy combining vanadium doping and carbon coating to prepare a silicon-based composite (V-Si@C). The prepared V-Si@C composite does not merely show improved conductivity but also improved electrochemical kinetics, attributed to the enlarged lattice spacing by V doping. Additionally, the superiority of this doping strategy accompanied by microstructure change is embodied in the relieved volume changes during the repeated charging/discharging process. Notably, the initial capacity of the advanced V-Si@C electrode is 904 mAh g –1 (1 A g –1 ) and still holds at 1216 mAh g –1 even after 600 cycles, showing superior electrochemical performance. This study offers an alternative direction for the large-scale preparation of high-performance silicon-based anodes.