High-Capacity, Cycle-Stable Zinc Vanadium Oxide Cathodes Enabled by In-Situ Electrochemical Oxidation for Zinc-Ion Batteries

The rechargeable aqueous zinc ion battery has great promise owing to its non-flammability and low cost, but is still limited by the lack of suitable cathode materials. Vanadium oxides cathode materials suffer from unsatisfactory rate and cycle performance for their poor conductivity and vanadium dissolution in aqueous solutions. Herein, we reported the zinc vanadium oxides with different stoichiometric converted from in-situ electrochemical oxidation of VOOH precursors in various space groups. The introduction of zinc atoms not only improves the conductivity of the materials but also stabilizes the layered structure without hindering ion migration and inhibits vanadium dissolution, thus greatly optimizing the comprehensive behaviors of the battery. The materials obtained through this route possess low crystallinity and such disordered structure facilitates electrolyte penetration and provides shortcuts for ion transportation. Zn_0.36V₂O₅·nH₂O has a specific capacity of 508.3 mAh/g and the retention of 95% and 80% after 2000 and 5000 cycles respectively.