Stability and Electrochemical Performance Analysis of an Electrolyte with Na+ Impurity for a Vanadium Redox Flow Battery in Energy Storage Applications

The effects of Na+ on the stability and electrochemical property of electrolytes are investigated for use in future applications. The V(V), V3.5+, and V(III) electrolytes are instable when the Na+ concentration is over 0.0048 mol L(-1 )in electrolyte. The increase in Na impurity will lead to an increase in viscosity and a decrease in conductivity, which definitely hinder the diffusion of VO2+/VO2+ and further reduce the electrochemical property of electrolytes. In addition, the temperature adaptability tests of batteries show that when the Na+ concentration is below 0.0048 mol L-1, the vanadium redox flow battery can work successfully in the temperature range -10 to 40 degrees C. Moreover, it is confirmed that Na/V precipitations physically adhere to the electrode surface, resulting in battery performance degradation.