Tailoring Local Chemical Coordination in Vanadium Pentoxide to Enable High Efficiency Zinc Ion Storage

Abstract

Vanadium oxides-based materials are one of promising cathode materials for aqueous zinc ion batteries (AZIBs) owing to their various chemical coordination and oxidation states rendering high theoretical specific capacity. However, the poor electronic conductivity and structural instability limit their practical application in AZIBs. In this study, these drawbacks of vanadium pentoxide are mitigated by introducing Al ions into the interlayer space (V2O5-Al). Compared with pristine V2O5, the V2O5-Al possesses an increased proportion of oxygen vacancy and improved diffusivity because of the tailored local chemical coordination and the strong chemical bonding from Al-O bonds. First-principles calculations suggest that pre-inserted Al ions embedded into the V2O5 layers enhances structural stability and improves the electrical conductivity of V2O5. While used as cathode for AZIBs, V2O5-Al electrode delivers a high capacity of 260 mAh g−1 at 4 A·g−1 and the 108% initial capacity maintained over 4400 cycles as well as an energy density of 260 Wh·kg−1 at 405 W·kg−1 based on the cathode. These superior electrochemical suggest the as-prepared Al-doped V2O5 hold great potential as the promising low-cost cathode materials in the ZIBs.