Synergistic engineering of oxygen-defect and heterojunction boosts Zn2+ (De)intercalation kinetics in vanadium oxide for high-performance zinc-ion batteries

Aqueous zinc-ion batteries (AZIBs) show tremendous potential in practical applications but are impeded by the limited comprehensive performance of cathode materials. Herein, an oxygen-defective vanadium oxide encapsulated by a thin-layer of amorphous carbon (denoted as O-d-VO@C) nanocomposite with a pea-like core-shell architecture that integrates oxygen defect engineering and heterojunction engineering has been prepared. For the first time, an electrochemically anodic oxidation method is employed to create oxygen defects for vanadium oxide, which can not only offer additional active sites to Zn2+ storage processes, but also aid in improving electronic conductivity of the host. Simultaneously, coating carbon materials on the surface of vanadium oxide nanoparticles to construct the heterojunction structure powerfully protects them from aggregation and effectively alleviates capacity fading. The elaborately designed porous microstructure endows the material with highly accessible active surface and abundant short migration pathways for reversible Zn2+ storage reactions. Consequently, the O-d-VO@C-based AZIB delivers comprehensive performance including an ultrahigh specific capacity up to -700 mAh & BULL;g(-1), impressive rate capability and decent cycling property. Such a reliable strategy that utilizing the synergistic engineering of oxygen-defect and heterojunction via electrochemical induce promotes the booming development of transition-metal oxides for various aqueous metal-ions storage.