| 作者 |
D. Q. Xin, S. D. He, X. D. Zhang, R. S. Li, W. Y. Qiang, S. J. Duan, Q. Lou, K. L. Deng, Z. F. Cheng, M. G. Xia* |
| 论文简介 |
Layered VS2 has high theoretical capacity and is considered a promising anode material for lithium-ion batteries. However, its poor cycle stability seriously affects its commercial application. The smart design of anode material microstructure is a crucial point to optimize the stability of batteries. Herein, a hierarchical composite of VS2/CNTs/C was successfully fabricated via a simple one-step solvothermal method, in which few-layer VS2 nanosheets were in situ self-assembled on a 3D CNTs cross-linked network skeleton and coated with a thin carbon layer. The interlayer spacing of (001) planes of VS2 nanosheets was expanded from 0.58 nm to 0.89 nm due to NH4+ intercalation during the solvothermal reaction. Density functional theory (DFT) calculations demonstrated that expanded interlayer spacing of VS2 can enhance the electron conductivity and significantly reduce the diffusion barrier of Li+. More importantly, the 3D CNTs skeleton could prevent the aggregation of VS2 nanosheets, provide a fast ionic/electronic migration channel, and ensure a large specific surface area and an extra buffer space. In addition, the carbon coating could further increase the conductivity and stabilize the connection between the VS2 nanosheets and CNTs skeleton. Benefiting from their synergistic effects, the VS2/CNTs/C electrode exhibited an enormous Li+ diffusion coefficient and favorable capacitive kinetics, and delivered excellent lithium storage performance, such as a large reversible specific capacity of 1075 mAh/g at 0.1 A/g, a high rate performance of 592 mAh/g at 2 A/g, and a remarkable cycling stability with a specific capacity of 629 mAh/g after 900 cycles at 1 A/g. This work may guide the design of other similar anode materials and help to understand their energy storage mechanism. |
Group 
(创新港)
