Nanocomposite Materials Based on Sulfonated Polyarylenethioethersulfone and Sulfonated Polybenzimidazole for Proton Exchange Membrane Fuel Cell Applications

Fabrication of novel nanocomposite membranes comprising a fully sulfonated polyarylenethioether sulfone (SPTES) and sulfonated poly(p-phenylene benzobisimidazole)(SPBI) and the evaluation of the membrane properties are described. The nanocomposite membrane was obtained via a solvent cast process in a mixture of DMAc and methanol as solvents. The nanocomposite membrane proton conductivity, as measured by four probe impedance spectroscopy, was found to increase with increase in the SPTES content in the nanocomposite. The highest proton conductivity obtained was similar to 80mS/cm at 65 degrees C and 85% relative humidity for the SPTES/SPBI 70/30 nanocomposite membrane which was considerably less than the 300 mS/cm for the pure SPTES membrane, but it was found that the swelling of the nanocomposite membranes was reduced due to the reduced water uptake of the nanocomposite membrane relative to SPTES. The morphology of the SPTES/SPBI nanocomposite membranes was examined by a combination of techniques, such as X-ray diffraction and scanning electron microscopy, to confirm the dispersion of SPBI in the nanocomposite. The membrane electrode assembly performance of the nanocomposite membranes was preliminary studied for H-2/O-2 fuel cells applications.