[Spectrophotometry analysis of different valence state of vanadium in vanadium battery electrolyte].

In the present paper, oxalic acid was used to reduce V(V) ion to V(IV) ion, then its complex with V(IV) was formed. By this method, four valence states of vanadium ions had different characteristic absorption peaks in the UV-Visible range. Based on these characteristic absorption peaks, qualitative and quantitative spectrophotometric analysis methods for different valence states of vanadium in vanadium battery electrolyte were established.