In situ synthesis of VO2 containing high-valent vanadium via surface oxidation of V2C MXene for robust near-interface reactions in aqueous zinc-ion batteries

• VO₂/V₂C heterostructure stabilizes near-interface reactions on MXene . • Uniform V₂C nanosheets on CNF prevent restacking and expose active sites. • DFT reveals optimized electron distribution at the VO₂/V₂C interface, enhancing kinetics. • Zn²⁺ diffusion and energy storage mechanism are systematically elucidated. Vanadium-based materials are promising candidates for cathodes in aqueous zinc-ion batteries (AZIBs), but balancing high capacity with long-term stability remains a challenge. High-valent vanadium enhances conductivity but is unstable, while low-valent vanadium improves stability but lacks sufficient conductivity and capacity. In this study, we improved the overall capacity and stability of the electrodes by in-situ growing VO 2 containing high-valent vanadium on V 2 C to suppress structural degradation, and by dispersing the VO 2 /V 2 C heterostructure nanosheets onto carbon nanofibers (CNF) to reduce V 2 C restacking and expose more active sites. Density Functional Theory (DFT) calculations suggest that the interface of the VO 2 /V 2 C heterostructure optimizes electron cloud distribution, highlighting the role of V 2 C in enhancing the reaction kinetics of VO 2 . Furthermore, the coordination effect between V 2 C and VO 2 enables stable near-interface reactions on V 2 C, further improving the electrochemical performance of the electrode. The optimized VO 2 /V 2 C@CNF-2 electrode achieves a discharge-specific capacity of 549 mAh g −1 at 0.1 A g −1 after 100 cycles and retains 300 mAh g −1 after 5000 cycles at 10 A g −1 . These findings provide new insights into enhancing AZIB cathode electrochemical performance and expand the application potential of V 2 C in aqueous batteries.