China Nonferrous Metallurgy

Vanadium compounds have good electrochemical activity and are expected to be used to enhance the electrochemical activity of vanadium battery electrodes, but the stability and electrochemical behavior of vanadium compounds in electrolytes have not been investigated yet. Therefore, the stability and electrochemical behavior of vanadium compounds such as V₂O₅ VO₂, V₂O₃, NaV₂O₅ and VN in acidic electrolytes have been investigated using E-pH diagram, open circuit potential method and cyclic voltammetry in this paper. In terms of stability, the E-pH diagram, dissolution tests and open circuit potential analysis of vanadium compounds show that VO₂ and Na V₂O₅ are unstable in vanadium battery electrolytes and undergo rapid dissolution; V₂O₅ is relatively stable in vanadium battery electrolytes and undergoes slow dissolution; V₂O₃ and VN are more stable in vanadium battery electrolytes and undergo small amounts of dissolution. In terms of electrochemical behavior, combined with cyclic voltametric analysis of vanadium compounds in 2.0mol·L^-1 H₂SO₄, 0.1mol·L^-1 V³⁺+2.0mol·L^-1 H₂SO₄, and 0.1mol·L^-1 V⁴⁺+2.0mol·L^-1 H₂SO₄ electrolytes, V₂O₅, V₂O₃ and VN undergo significant redox reactions at 0.4 to 1.5V and no significant redox reactions at -0.8 to -0.2V; VN has better catalytic effect on the V5+/V4+ and V³⁺/V²⁺ electro pair reactions, with V2O3 being the next most catalytic and V₂O₅ the weakest. Therefore, V₂O₃ and VN can be used as catalytic materials for V³⁺/V²⁺ electro pair reactions to improve the electrochemical activity of vanadium battery anodes to achieve improved performance of vanadium batteries.