V2O3 as cathode of zinc ion battery with high stability and long cycling life

Aqueous zinc ion batteries (AZIBs) attract increasing attention due to their low cost, safety, environmental protection, and potential application in stationary energy storage. However, the realization of high discharge voltage, high cycle stability, and high energy density is still the main challenge. Herein, we report a highly stable V2O3 sample synthesized by the reduction method of boron with high-temperature molten salt. In this method, molten salt was used as solvent to react between solid and liquid, and the ion velocity is significantly accelerated; the reaction temperature and time are effectively reduced. The electrochemical performance results show that V2O3 can provide a maximum discharge specific capacity of 207 mAh g−1 at 0.1 A g−1. The V2O3 electrode exhibits a high specific discharge capacity of 110 mAh g−1 after 2500 cycles at 3 A g−1; the capacity retention rate is 82.1%. Its electrochemical performance is obviously better than that of commercial V2O3. The electrochemical kinetic studies show that V2O3 electrode has a fast diffusion coefficient of zinc ions. This work provides an effective strategy to enhance the energy density and cycling stability of aqueous zinc ion-based batteries.