Oxygen vacancy engineering boosted manganese vanadate toward high stability aqueous zinc ion batteries

Aqueous zinc-ion batteries (AZIBs) are attractive alternatives to conventional battery technologies owing to their low-cost, safety and environmental friendliness. The development of AZIBs has thus far proceeded rapidly; however, finding suitable materials for AZIB cathodes with high capacity, long-cycle stability, fast reaction kinetics has proved challenging. In this study, a manganese vanadate precursor (Mn0.04V2O5·1.17 H2O; MVO) was prepared using a simple hydrothermal method and calcined at a low temperature (250 °C) to generate oxygen vacancies (Mn0.04V2O5−x·0.64 H2O; MVO-250). The presence of oxygen vacancies effectively provide active sites, increase surface reactivity to improve zinc-ion storage, and inhibit the dissolution of electrode materials in the electrolyte. Consequently, MVO-250 exhibits a superior specific capacity and long-cycle performance to MVO. Moreover, after 4000 cycles at 5 A g−1, the discharge specific capacity of the MVO-250 electrode remain at 150 mA h g−1, while that of MVO is only (76 mA h g−1). Owing to its high pseudocapacitance (90.5%) at 1.0 mV s−1, MVO-250 has a higher zinc ion diffusion coefficient than MVO (77.2%). This research demonstrates the diverse potential applications prospect of the modification of AZIBs cathode materials with oxygen vacancies.