Engineering VO₂/VS₂ heterojunction nanobelts for high-rate aqueous Zn-ion batteries with superior Zn2+intercalation kinetics

The development of aqueous zinc-ion batteries (AZIBs) is critically hindered by the absence of suitable cathode materials that simultaneously provide rapid Zn2+ diffusion kinetics and high energy density. We report a two-dimensional VO₂/VS₂ heterojunction nanobelt (VOSHN) as a superior cathode material enhancing specific capacity and longer cycle stability with improved Zn2+ diffusion kinetics. Further electronic features of the heterojunction and their diffusion behavior of Zn2+ in VOSHN are investigated by using DFT calculations. It emphasizes the lower Zn2+ diffusion barrier of 1.32 eV in VOSHN enabling high-rate performance in AZIBs. Consequently, the Zn//VO₂/VS₂ cell demonstrates a high specific capacity of 351 mAh g−1 at 0.2 A g−1 with capacity retention of 93.8% up to 3000 cycles at 3 A g−1. Furthermore, the Zn//VO₂/VS₂ battery demonstrates a notable capacity of 44.89 mAh g−1 with a retention of ∼71% over 1500 cycles at a high current density of 5 A g−1. The fascinating VOSHN offers synergistic effect delivering structural robustness, fast-charge transfer, and effective Zn2+ intercalation and hence improves the overall performance of aqueous Zn-ion batteries. This work provides novel routes for the design of 2D heterojunction cathode materials for practical AZIBs.