Development of Hybrid Membranes Nafion-ZrO2 for PEM Fuel Cells

Six hybrid membranes were synthesized by the sol-gel process, Nafion was used as a polymeric matrix and it was modified with 1% wt. of  N-HfO₂, N-ZrO₂, N-La₂O₃, N-(HfO₂-ZrO₂), N-(HfO₂-La₂O₃) and N-(ZrO₃-La₂O₃), with a thickness interval of 120-160μm. The proton conductivity (CP) was evaluated by four-electrode method using a commercial conductivity cell (Bekktech®), a potenciostat-galvanostat (Autolab PGSTAT 302) in connection with a Fuel Cell Test Station (PSCompuCell of Electrochem®) was used to evaluate the hybrid membranes in a fuel cell conditions, in which relative humidity  and temperature were established at 50-100% and 30-120 ˚C respectively. The N-La₂O₃ and N-HfO2 membranes showed a CP of 0.12 S/cm^-1 (100%RH-30˚C) and 0.13-0.11 S/cm^-1 (100%RH-80˚C - 50%RH-120˚C) respectively, while the CP of Nafion 115 is 0.09 S/cm^-1 (100RH-30˚C). Water up-take and swelling at 30-100 °C was also measured.  First results show a promising incorporation of a N-HfO2 membrane for PEM Fuel Cells performance at high temperature and low relative humidity.