Proton Conducting Membranes Obtained by Doping Radiation‐Grafted Basic Membrane Matrices with Phosphoric Acid

Abstract

Abstract By grafting 4‐vinylpyridine (4VP), N ‐vinylformamide (NVF), and 1‐vinylimidazole (1VIm) onto electron beam irradiated ETFE and FEP films, the basic membrane matrices ETFE‐ graft ‐poly(4VP), FEP‐ graft ‐poly(4VP), ETFE‐ graft ‐poly(1VIm), and ETFE‐ graft ‐poly(vinylamine), after subsequent hydrolysis of ETFE‐ graft ‐poly(NVF), can be obtained. These matrices are doped with phosphoric acid to produce acid–base composite materials that exhibit high proton conductivities up to 100 mS · cm −1 at high temperatures (120 °C) and no humidification. The produced membranes are robust, flexible, and mechanically stable even at high doping levels and endure temperatures of up to 160 °C. Preliminary tests in H 2 /O 2 fuel cells provide power densities between 75 and 150 mA · cm −2 at 120 °C without humidification. magnified image