Electrochemical properties of ZrO₂-doped V₂O ₅ amorphous powders with spherical shape and fine size

Amorphous V₂O₅ powders with zirconia (ZrO ₂) dopant are prepared by one-pot spray pyrolysis at temperatures above the melting temperature of V₂O₅. The powders with 7 wt % ZrO₂ are completely spherical and dense with a clean surface, on which crystals of pure V₂O₅ powders are scarcely observed. The V₂O₅ powders with 7 wt % ZrO₂ have uniformly distributed V and Zr components. The uniformly distributed Zr component disturbs the crystallization of V₂O₅ during the quenching of the melted powders. These powders also give smooth initial discharge curves with a single slope, which is typical to amorphous materials. The discharge capacities of the V₂O₅ powders with 7 wt % ZrO₂ are 309, 269, and 222 mA h g^-1 after the first, second, and 50th cycles, respectively, even at a high current density of 294 mA g^-1. The capacity retention measured after the first cycle is 83% after 50 cycles.