Enhancement of Reversibility of Cr(III)/Cr(II) Redox Couple In Fe-Cr Flow Cell with Bi-Pb Electroplated Carbon Felts

Abstract

Improvisation of Fe-Cr redox flow cell performance was significantly related to reversibility of the Cr(III)/Cr(II) redox couple. To catalyze this redox reaction Bi and Pb metals were electroplated on carbon felt for redn. and oxidn. of chromium. To achieve a better performance of redox flow cell these electroplated carbon felts are used on neg. side of the flow cell. The flow cell expts. are carried out with only Bi electroplated felts using 0.01N PbCl2 as additive in anolyte and another carbon felts are electroplated with the combination of Bi-Pb and used on neg. side of the cell without any additive. The exptl. results obsd. that the Bi electroplated felts with PbCl2 additive shows 100% chromium redn. efficiency, 96% coulombic efficiency and 65% energy efficiency. While Bi and Pb combination felts without any additive has shown 100% chromium redn. efficiency, 98% coulombic efficiency and 72% energy efficiency. The cell operated with 5 L of electrolyte contg. 1.3N active materials dissolved in 2N HCl soln. 100 cm2 carbon felt samples were utilized as electrodes at a c.d. of 50 mA/cm2. Nafion-117 PFSA membrane was used as a separator because of its high chem. and mech. stability. [on SciFinder(R)]