Sulfonated poly(arylene ether sulfone)s membranes with distinct microphase-separated morphology for PEMFCs

Copoly (arylene ether sulfone)s was employed for proton exchange membrane preparation via atom transfer radical polymerization followed by mild sulfonation, enhanced phase-separated morphology and favorable proton conductivity were achieved. The comprehensive ex-situ properties of a range of membranes with different ion exchange capacities were characterized alongside the fuel cell performances investigation. The membranes exhibit higher water uptake, which is beneficial to the proton conduction, compared to Nafion® 211 while maintaining similar swelling ratio. The prepared membranes exhibit reasonably high proton conductivity (0.16 S/cm at 85 °C) benefitting from the well-defined microstructure and high connectivity of the hydrophilic domains. Considering the comprehensive property, membrane with moderate ion exchange capacity (1.39 mmol/g) was employed to fabricate the membrane electrode assembly and peak power density of 0.65 W/cm² at 80 °C, 60% relative humidity was achieved for a H₂/O₂ fuel cell, these hydrocarbon membranes can therefore be implemented in PEMFCs.