Figure : Recovery efficiency vs. period between regeneration events. Test conditions: negolyte comprised 7.0 ml (10 ml for the test in 1.5M OH -) of 0.1 M DHAQ and the posolyte comprised 120 ml of 0.06 M potassium ferrocyanide and 0.03 M potassium ferricyanide. Cell cycling was performed under a constant current density of 50 mA/cm 2 followed by a potentiostatic hold. The cutoff voltage for the charge and discharge steps were 1.4 V and 1.0 V, respectively. Cutoff current densities for the charge and discharge steps were 2 mA/cm 2 . Regeneration steps were performed under a constant current density of 10 mA/cm 2 followed by potentiostatic hold at -0.15 V until a cutoff current density of 0.75 mA/cm 2 was reached.