V2O3/VN@C Heterostructures with Fast Charge Transfer as High-Performance Cathodes of Zinc-Ion Batteries

Zinc-ion batteries (ZIBs) are promising candidates for next-generation energy storage systems due to their high energy density and low cost. However, challenges such as poor cycling stability and sluggish kinetics hinder their practical application. In this study, we propose a novel heterostructure composed of microsphere V2O3 integrated with vanadium nitride (VN) and uniformly coated with carbon (V2O3/VN@C) to address these challenges. The optimized V2O3/VN@C heterostructure exhibits excellent stability during cycling within a voltage window of 0.1-1.3 V (vs Zn/Zn2+). The V2O3/VN@C electrode exhibits a large specific capacity (278 mA h g(-1) at 200 mA g(-1)), remarkable cycling stability (96% capacity retention after 400 cycles at 200 mA g(-1)), improved rate capacity (141 mA h g(-1) at 15 A g(-1)), and higher energy density besides. Furthermore, the investigation of the Zn-ion storage mechanism in the V2O3/VN@C electrode reveals that the heterostructure effectively enhances the conductivity and inhibits the phase transition of V2O3 to a high-valence state. During charging and discharging, the heterostructure facilitates the desolvation process of Zn[H2O](6)(2+) and accelerates the charge transfer kinetics of the electrodes. The proposed strategy provides new opportunities for designing long-cycling and high-energy cathodes for AZIBs and beyond.