Semi-interpenetrating network electrolyte membranes based on sulfonated poly(arylene ether sulfone) for fuel cells at high temperature and low humidity conditions

Semi-interpenetrating network (semi-IPN) membranes based on sulfonated poly(arylene ether sulfone) (SPAES) were developed for application in polymer electrolyte membrane fuel cells (PEMFCs) operating at high temperature (> 100 °C) and low relative humidity (< 50% RH) conditions. The semi-IPN membranes were prepared by a heating procedure using SPAES solutions containing vinyl phosphonic acid (VPA) and diethylene glycol dimethacrylate (DEGDMA). When the membrane was prepared using the optimized molar ratio of VPA to DEGDMA, it showed a very high proton conductivity of up to 10 mS cm− 1 at 120 °C and 40% RH, and high mechanical property with a tensile strength of 43.2 MPa. Membrane electrode assemblies (MEAs) prepared using this semi-IPN membrane showed a peak power density of 180 mW cm− 2 at 120 °C and 40% RH, which is better than that of the MEAs prepared using SPAES membrane (145 mW cm− 2). The semi-IPN membranes also showed very good electrochemical stability during the durability test.