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

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 Zn²⁺ ion diffusion, which restricts their practical usage. Therefore, a homo-interphase design of vanadium oxide containing both V⁵⁺ and V⁴⁺ 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.