The cell voltage for the regeneration step should be adjusted accordingly when a posolyte with a different composition is used. Figure shows the conversion efficiency vs. the maximum potential the negolyte experiences at each regeneration cutoff voltage reported in Figure . These values were measured with the help of a reference electrode (RE) as described in the SI (Figure ). According to Figure , the conversion efficiency approaches a maximum when the negolyte experiences an oxidation potential of around 0.45 V (vs. SHE) beyond which the conversion efficiency remains essentially unchanged. maximum oxidation voltage (vs. SHE) that the negolyte experiences during the regeneration step. Test conditions: negolyte contained 6.5-7.0 ml of 0.05 M DHA and the posolyte comprised 120 ml of 0.04 M potassium ferrocyanide and 0.02 M potassium ferricyanide. DHA oxidation condition: constant current density at 2 mA/cm 2 followed by potentiostatic hold until a cutoff current density of 0.75 mA/cm 2 . Subsequent cycling of the formed DHAQ was performed under constant current density at 50 mA/cm 2 followed by a potentiostatic hold. The cutoff voltage for the charge and discharge steps were 1.4V and 1.0 V, respectively. Cutoff current densities for the charge and discharge steps were 2 mA/cm 2 .