Evaluation of new ion exchange membranes for direct borohydride fuel cells

Several radiation grafted ion exchange membranes were prepared and evaluated in half-cells and direct borohydride fuel cells (DBFC) using voltammetric and steady-state polarisation techniques. The peak power density of 112 mW cm−2 was achieved in a DBFC with an ETFE-g-PSSA membrane using a solution of 1.32 M sodium borohydride and 2.5 M sodium hydroxide, 1 bar oxygen at 85 °C. The chemical and mechanical stabilities of the membranes were tested under various conditions. The membrane performance was compared to that obtained with the benchmark Nafion® 117 membrane. The results are discussed based on the electrical, chemical, structural and mechanical properties of the membranes.