Properties and performance of composite electrolyte membranes based on sulfonated poly(arylenethioethersulfone) and sulfonated polybenzimidazole

A novel composite membranes comprising a sulfonated polyarylenethioethersulfone homopolymer (SPTES-100) and a sulfonated poly(p-phenylene benzobisimidazole) (SPBI), was described in this article. The composite membrane was obtained via a solution cast process in a mixture solvent of N, N-Dimethylacetamide (DMAc) and methanol (MeOH). The proton conductivity of the composite membranes was found to increase with the SPTES-100 content increased. The higher proton conductivity was ∼110 mS/cm at 85 °C and 85% relative humidity for the SPTES/SPBI 70/30 (wt) composite membrane which was considerably less than that of the 300 mS/cm of the SPTES-100 membrane. The mechanical properties indicated that the swelling of the composite membranes was reduced, which is relative to the SPTES-100 polymers, due to the reduced water uptake of the composite membrane by introducing the SPBI into the SPTES polymer matrix. The morphology of the SPTES/SPBI composite membranes was examined by a combination of techniques such as scanning electron microscopy (SEM) and elemental mapping to confirm the dispersion of the SPBI and study the micro-structure of the composite. The membrane electrode assembly (MEA) performance of the composite membranes was preliminary studied for H2/Air fuel cells applications.