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ABSTRACT: Simultaneously improving the proton conductivity and mechanical properties of a polymer electrolyte membrane is a considerable challenge in commercializing proton exchange membrane fuel cells. In response, we prepared a new series of miscible polymer blends and thus the corresponding crosslinked membranes based on highly sulfonated poly(ether ether ketone) and sulfonated polybenzimidazole. The blended membranes showed more compact structures, due to the acid‐base interactions between the two constituents, and improved mechanical and morphological properties. Further efforts by doping sulfonated graphene oxide (s‐GO) forming composite membranes led to not only significantly elevated proton conductivity and electrochemical performance, but also better mechanical properties. Notably, the composite membrane with the filler content of 15 wt % exhibited a proton conductivity of 0.217 S cm−1 at 80 °C, and its maximum power density tested by the H2/air single PEMFC cell at room temperature reached 171 mW cm−2, almost two and half folds compared with that of the native membrane. As a result, these polymeric membranes provided new options as proton exchange membranes for fuel‐cell applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46547. [ABSTRACT FROM AUTHOR]

Intent on developing efficient proton exchange membranes used for direct methanol fuel cells as well as hydrogen fuel cells, a series of membranes based on sulfonated polyetheretherketone and sulfonated polyphosphazene-graft copolymers is prepared by cross-linking reaction because the former material has good enough mechanical property, while the latter is excellent in the proton transfer. The cross-linked membranes combine the advantages of the two kinds of polymers. Among them, the membrane poly[(4-trifluoromethylphenoxy)(4-methylphenoxy)phosphazene]-g-poly {(styrene)11-r-[4-(4-sulfobutyloxy)styrene]33-sulfonated poly(ether ether ketone)75 (CF3-PS11-PSBOS33-SPEEK75) shows a proton conductivity at 0.143 S cm−1 under fully hydrated conditions at 80 °C and performs tensile strength about five times as much as did the sulfonated polyphosphazene membrane CF3-PS11-PSBOS33. Further doping of sulfonated single-walled carbon nanotubes (S-SWCNTs) into the cross-linked membranes on the screening of additives gives composite membrane CF3-PS11-PSBOS33-SPEEK75-SWCNT possessing proton conductivity of 0.196 S cm−1, even higher than that of Nafion 117 and a tensile strength comparable to that of Nafion 117. However, this significance of the composite membrane in the proton conduction is not observed in the test with a H2/air fuel cell when it shows a maximal power density of 280 mW cm−2 at 80 °C, whereas 294 mW cm−2 is observed for CF3-PS11-PSBOS33-SPEEK75. [ABSTRACT FROM AUTHOR]

Highly sulfonated poly(ether ether ketone) (PEEK) polymer is hydrogenated and then readily grafted on GO to provide nanohybrid material GO-g-SPEEK. The material shows good enough properties for the preparation of proton exchange membranes. First, the GO-g-SPEEK membrane has much more water uptake but less water swelling compared with Nafion ® , and an excellent proton conductivity of 0.219 Scm −1 at 90 °C. Then, it demonstrates a peak power density of 112 mWcm −2 when utilized in a H 2 /air fuel cell at circumstance temperature. Further, blending of the materials with Nafion leads to composite membranes of GO-g-SPEEK/Nafion, which has a close proton conductivity to that of GO-g-SPEEK but far higher cell performances. Of the composite membranes, GO-g-SPEEK/Nafion-33 reveals cell performance of 182 mWcm −2 at 25 °C and 213 mWcm −2 at 60 °C. These results indicate that Nafion might serve only as an enhancer of compatibility between membrane and Nafion-supported catalyst phase in the membrane electrode assembly, and therefore suggest that the GO-g-SPEEK may be a promising membrane material for the application in proton exchange membrane fuel cells. [ABSTRACT FROM AUTHOR]