Saturn-like N-Doped VS<sub>2</sub> Cathode with a Three-Step Deintercalation Mechanism under a Wide Voltage Range for Enhancing the Electrochemical Kinetics of Zinc-Ion Batteries
Huayu Wu, Xiaoyu Wu, Rui Wang, Xing Chen, Rongguan Lv, Lele Fan, Fanjie Kong, Lubin Ni, Guowang Diao, Rong Xing, Ming Chen
Abstract
Saturn-like (SL) N-doped VS 2 as a cathode material for aqueous zinc-ion batteries (ZIBs) is synthesized into hollow mesoporous carbon spheres via a confinement growth strategy. SL VS 2 @CS shows a novel three-step deintercalation process at a wide voltage range (0–1 V), which efficiently enhances the Zn 2+ storage capacity. In addition, the confined effect of SL VS 2 @CS can emphatically inhibit the pulverization and volume effect induced by massive Zn 2+ insertion, and the finite element simulation confirms that the Saturn-like structure can alleviate the stress distribution caused by the zincification process. The density functional theory calculation verifies that the N-doped VS 2 @CS greatly reduces the migration energy barrier. The electrochemical reaction process and structure evolution of SL VS 2 @CS in ZIBs are analyzed by ex situ methods, which demonstrate the three-step deintercalation mechanism and highly reversible process. The soft-package ZIBs assembled with SL VS 2 @CS as the cathode exhibit the potential for practical application with superior cycling stability (322.2 mA h g –1 at 0.5 C, 500 cycles) and good rate performance.