Cross-linked PEEK-WC proton exchange membrane for fuel cell

The low cost proton exchange membrane was prepared by cross-linking water soluble sulfonated-sulfinated poly(oxa-p-phenylene-3,3-phthalido-p-phenylene-oxa-p-phenylene-oxy-phenylene) (SsPEEK-WC). The prepared cross-linked membrane became insoluble in water, and exhibited high proton conductivity, 2.9 × 10−2 S/cm at room temperature. The proton conductivity was comparable with that of Nafion® 117 membrane (6.2 × 10−2 S/cm). The methanol permeability of the cross-linked membrane was 1.6 × 10−7 cm2/s, much lower than that of Nafion® 117 membrane.