水合磷酸氧钒正极水系锌电池的储能性能OA

To explore the mechanism and overcoming methods for rapid function failure of polyanionic compounds in the application of aqueous zinc batteries,which were with high electrode potentials.The electrochemical performance of hydrated vanadyl phosphate,as a type of model cathode material,was systematically investigated in ZnSO4 and ZnCl2 electrolytes with varying concentrations,as well as in a mixed ZnCl2-H3 PO4 electrolyte.The results indicated that the function failure of hydrated vanadyl phosphate was primarily attributing to dissolution of vanadium and loss of PO 43-,which induced an irreversible phase transformation reaction.The dissolution of vanadium shortened the electrode lifespan,while the loss of PO43-led to the disappearance of the high-potential charge/discharge plateau.ZnCl2 with high concentration would reduce the activity of free water,thereby suppressed the dissolution of vanadium,while the introduction of H3PO4 lowered the thermodynamic spontaneity of the reaction.In the mixed electrolyte consisting of 10 mol/kg ZnCl2 and 0.5 mol/kg H3PO4,the specific capacity of hydrated vanadyl phosphate electrode was up to 61 mA·h/g,whose capacity retention reached 130％after 50 galvanostatic charge-discharge cycles.All of the results confirmed the enhanced cycling stability.