Preparation and evaluation of composite membrane for vanadium redox battery applications

Abstract A composite membrane has been fabricated from Daramic (a microporous separator), treated with Amberlite 400CG (an ion-exchange resin), and cross-linked using divinyl benzene. Coulombic, voltage and energy efficiencies of 95, 85 and 83%, respectively, have been achieved when this membrane is employed in the vanadium redox cell. Long-term charge/discharge cycling has been conducted on the membrane for more than 700 cycles (4000 h), without any appreciable drop in performance. The composite membrane satisfies the stability, low area resistance, selectivity, and low-cost requirements for use as a separator in the vanadium redox battery.