Effects of temperature and concentration on vanadium electrolyte performance

Vanadium battery system is mainly composed of diaphragm, electrode plates, electrodes; electrolyte storage tank and circulation pump and so on. The changes of vanadium ion valence state during charging and discharging realize the energy storage and release. The electrochemical cyclic voltammetric behaviors were studied in various concentrations of vanadium electrolyte at different temperatures. The results show that the ion number participating in the electrochemical reaction increases with the increase of the vanadium ion concentration at the same temperature, and vanadium battery can produce larger output current. Simultaneously, the reversibility of electrochemical reaction tends to be poor with the increase of vanadium ion concentration and the energy loss of vanadium battery during charge and discharge cycles will increase, which will reduce the energy efficiency. For vanadium electrolyte under the same concentration, the peak current value of oxidation and reduction reaction increases with the rising of temperature. It proves that the output current of the vanadium flow battery can be improved by properly increasing the temperature of vanadium electrolyte.