Sulfonated polySEPS/hydrophilic-SiO2 composite membranes for polymer electrolyte membranes (PEMs)

Sulfonated polystyrene-block-poly(ethyl-ran-propylene)-block-polystyrene (S-polySEPS)/hydrophilic-SiO2 composite membranes were prepared by direct-mixing hydrophilic-SiO2 particles with S-polySEPS in the blending solvent (THF/DCE/IPA). Despite the hydrophilic-fillers, the S-polySEPS/hydrophilic-SiO2 composite membranes showed that the hydrophilic-SiO2 particles were very-well dispersed within the S-polySEPS matrix. Most of the prepared S-polySEPS/hydrophilic-SiO2 composite membranes had higher proton conductivity and water uptake than Nafion®117. In particular, S-polySEPS/hydrophilic-SiO2 2 wt% membrane (1.50 × 10−1 S/cm) showed much higher proton conductivity than that of the Nafion®117 (9.8 × 10−2 S/cm) at 90 °C. The current density was 1090 mA cm−2 at 0.7 V.