VANADIUM REDOX CELL ELECTROLYTE OPTIMIZATION STUDIES

The stability of the positive electrolyte of the vanadium redox cell has been studied at various temperatures and at different solution compositions and solution state-of-charge (SOC). It has been found that at elevated temperatures for extended periods, V(V) can slowly precipitate from solution, the extent and rate of which being dependent on temperature, vanadium and sulphuric acid concentration as well as the SOC of the electrolyte. A H2SO4 concentration of 3-4 m has been found to be more suitable than 2 m, not only from the point of view of increased stability, but also because of the higher electrolyte conductivity which leads to increased voltage efficiencies during battery cycling. © 1990 Chapman and Hall Ltd.