Single cell performance and electrochemical characterization of photocrosslinked and post-sulfonated SEBS-DVB membranes

This work describes the preparation of UV photocrosslinked and post-sulfonated s(SEBS-DVB) membranes for their use as proton exchange membranes (PEM). Photocrosslinking is chosen as a useful method to reduce water uptake and enhance the dimensional stability while post-sulfonation reaction prevents the possibility of sulfonic groups may photocrosslink between different molecules. The experimental membranes are evaluated and compared with pristine sSEBS in terms of IEC, swelling ratio (in water and chloroform), FTIR-ATR and thermal properties (TGA, DSC). Morphology is investigated using SEM and AFM. The membranes are fitted into single cells and electrochemically characterized in order to determine in situ through-plane proton conductivity, hydrogen crossover and cell performance at 80 °C, atmospheric pressure and 100% relative humidity. The effects exerted by crosslinkable agent amount (DVB) and irradiation time are examined. Thus, s(SEBS-DVB 75-25) irradiated for 15 minutes highlights significantly from the rest, reaching a maximum current density of about 2300 mAcm−2 and a maximum power density greater than 700 mWcm−2 while these values for sSEBS are 1700 mAcm−2 and 478 mWcm−2, respectively. The results indicate that photocrosslinking and post-sulfonation are effective approaches to reduce the problem of excessive water swelling in membranes based on sSEBS and to endue a good performance.