Homo‐Interphase Engineering of Vanadium Oxide Cathode with Enhanced Diffusion Kinetics for High‐Rate Aqueous Zinc‐Ion Batteries

Abstract Vanadium oxide‐based cathode materials are often used in zinc‐ion batteries due to their high theoretical specific capacity, low cost, and environmental friendliness. However, they suffer from low ionic conductivity and sluggish Zn 2+ ion diffusion, which restricts their practical usage. Therefore, a homo‐interphase design of vanadium oxide containing both V 5+ and V 4+ oxidation states, combining the high electronic conductivity and high diffusion coefficient, leads to high‐performance cathode materials for zinc ion batteries. The homo‐interphase vanadium oxide demonstrates the high specific capacity of 260 mAh g −1 at 0.1 A g −1 and rate capability compared to its pristine counterparts. Moreover, it shows very good cyclic stability up to 3000 cycles with 65% retention at 10 A g −1 and 91% retention up to 100 cycles at 0.1 A g −1 . The ex situ and post‐cycling analysis further enlightens the structural and morphological robustness of the material during the charge–discharge process. Finally, a flexible device shows the potential wearable application of the zinc‐ion battery that uses homo‐interphase vanadium oxide cathode material. This study demonstrates the development of potential stable cathode materials by the homo‐interphase strategy of vanadium oxides, advancing the zinc ion battery technology for sustainable future energy storage devices.