Evaluation of properties and performance of poly(ether sulfone ketone) membranes in proton exchange membrane fuel cells

Two series of sulfonated poly(ether sulfone ketone)s have been synthesized. The effect of different ratios of sulfone: ketone functional groups on the properties and performance of membranes is studied. The density, ion-exchange capacity, water absorption, swelling ratio, proton conductivity, thermal and oxidative stability of membranes are determined. The results showed that membranes with higher contents of sulfone functional groups show lower density and consequently higher water absorption and swelling ratio values. A precise evaluation of the effect of different sulfone: ketone functional group ratios on the analytical acid concentration and the effective proton mobility and their relationship with water absorption have been performed. The proton conductivity values are between 71–78 mS.cm−1 at 30°C and 117–208 mS.cm−1 at 80°C. The effective proton mobilities at 80°C are in the range of 10.27 × 10 −4 to 16.68 × 10 −4 cm2.V−1.s−1. The highest current density for prepared membranes in H2/O2 single cell at 100% relative humidity and 80°C is 1900 mA.cm−2.