Optimization studies on a Fe/Cr redox flow battery

The performance of a Fe/Cr redox flow battery which operates in bipolar mode is described. The optimization studies on electrolyte composition, temperature and membrane type are presented. These studies have achieved a coulombic efficiency of 97% and an energy efficiency of 73% for an electrolyte composition of 2.3 M HCl + 1.25 M FeCl2 + 1.25 M CrCl3, working at 44 °C with a current density of 40 mA/cm2 and using the Nafion 117 membrane. A maximum discharge power density of 73 mW/cm2 has been obtained.