Simultaneous enhancement of proton conductivity and methanol resistance of sulfonated poly(phthalazinone ether sulfone ketone)/superacid sulfated zirconia composite membranes for direct methanol fuel cells

Sulfonated poly(phthalazinone ether sulfone ketone) (SPPESK) is a kind of novel non-fluorine polymer, whose high proton conductivity is dependent on high degree of sulfonation, which resulting in loss of dimensional stability. SPPESK/superacid sulfated zirconia (SZrO2) composite proton exchange membranes are fabricated first. The composite membrane shows good dimensional stability, ascribing to the restriction effect of hydrogen bonding force on the mobility and relaxation of polymer chains. Introducing SZrO2 simultaneously enhances the conductivity and anti-methanol permeation, owing to the connected ion domains, enlarged and aggregated ion clusters, excess proton conduction sites, and good blocking effect to methanol of SZrO2. For composite membrane containing 1.5 wt % SZrO2, the highest conductivity of 180 mS cm(-1) is obtained at 80 degrees C. Compared with pristine SPPESK and Nafion 115, the methanol permeability is reduced by 54 and 77%, and the maximum power density of direct methanol fuel cell is enhanced by 133 and 25%. (c) 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46758.