Construction of V2O3/VN@GO heterojunction cathodes derived from polyoxovanadates for high-performance aqueous zinc ion batteries

Abstract

Aqueous zinc ion batteries (AZIBs) based on vanadium oxides are considered promising candidates for large-scale energy storage due to their environmental friendliness and high safety. However, the poor cyclability and sluggish reaction kinetics of vanadium-based cathodes greatly limit the commercial application of AZIBs. Herein, the stable V₂O₃/VN heterostructures coated with graphene oxide (V₂O₃/VN@GO), derived from polyoxovanadates via an in situ pyrolysis process, are designed as cathode materials for ultrahigh-rate AZIBs. The highly conductive GO promotes the generation of oxygen defects and alleviates vanadium dissolution. The synergistic effect of V₂O₃/VN@GO heterostructures with oxygen defects significantly accelerated the electron/ion transfer kinetics and reduced the Zn-ion migration energy barrier. Therefore, the as-fabricated V₂O₃/VN@GO cathode delivers a high specific capacity of 488.1 mA h g⁻¹ at 0.5 A g⁻¹ and excellent cycling stability (91.4% capacity retention after 3000 cycles at 10 A g⁻¹).