Phosphoric acid-doped SDF-F/poly(VI-co-MPS)/PTFE membrane for a high temperature proton exchange membrane fuel cell

Sulfonated poly(fluorinated arylene ether)s (SDF-F)/poly[(N-vinylimidazole) -co-(3-methacryloxypropyl-trimethoxysilane)] (poly(VI-co-MPS))/ poly(tetrafluoroethylene) (PTFE) is prepared for a high temperature proton exchange membrane fuel cell (PEMFC). The reaction of the membrane with phosphoric acid forms silicate phosphor, as a chemically bound proton carrier, in the membrane. Thus-formed silicate phosphor, nitrogen in the imidazole ring, and physically bound phosphoric acid act as proton carriers in the membrane. The physico-chemical and electrochemical properties of the membrane are investigated by various analytical tools. The phosphoric acid uptake and proton conductivity of the SDF-F/poly(VI-co-MPS)/PTFE membrane are higher than those of SDF-F/PVI/PTFE. The power densities of cells with SDF-F/poly(VI-co-MPS)/PTFE membranes at 0.6 V are 286, 302, and 320 mW cm^-2 at 150, 170, and 190 °C, respectively. Overall, the SDFF/ poly(VI-co-MPS)/PTFE membrane is one of the candidates for anhydrous HT-PEMFCs with enhanced mechanical strength and improved cell performance.