Sulphonated polysulphone membranes for medium temperature in polymer electrolyte fuel cells (PEFC)

The synthesis of sulphonated polysulphone (PSF) with three different sulphonation levels was carried out and several membranes were developed with the corresponding polymers. The membranes were characterised in terms of ion exchange capacity (IEC), water up-take at different temperatures, TG-DSC analysis, FT-IR investigation and methanol permeability measurements. The results obtained were correlated to the electrochemical data. Electrochemical tests in a single cell fed with H2/air were also carried out in the temperature range 80-120 1C and compared to commercial Nafion 112 (N112). The chemical-physical properties of the tested membranes have good reproducibility and comparable values with commercial Nafion. A maximum power density of about 360mWcm2 for PSF 48% at 0.6V and T ¼ 120 1C was obtained, and the measured OCV value for the PSF membrane is higher than the perfluorinated membrane with a comparable thickness, indicating a lower gas permeability of PSF polymer.