The energy storage behavior of a phosphate-based cathode material in rechargeable zinc batteries

Abstract

The energy storage behavior of the Li₃V₂(PO₄)₃ cathode in zinc batteries is evaluated. The dissolution or decomposition into vanadium oxide in aqueous electrolytes is revealed. Using the optimal combination of water and acetonitrile solvents in electrolyte, those processes are effectively prevented without sacrificing the Zn²⁺ de/insertion kinetics. Further investigation demonstrates a water induced phase transformation into a VOPO₄ type structure, which is still a polyanion material and preserves the high voltage. It delivers 128 mA h g⁻¹ capacity at 1C with 1.45 V discharge voltage, and 87 mA h g⁻¹ capacity is retained at 10C. A stable cycling is obtained for 1000 cycles.