Fabrication and characterization of sulfonated polybenzimidazole/sulfonated imidized graphene oxide hybrid membranes for high temperature proton exchange membrane fuel cells

The sulfonated polybenzimidazole (sPBI)/sulfonated imidized graphene oxide (SIGO) was evaluated to be a potential candidate for high temperature proton exchange membranes fuel cells (HT-PEMFCs). Multifunctionalized covalently bonded SIGO is incorporated in sPBI matrix to resolve the drawbacks such as low proton conductivity, poor water uptake, and ion-exchange capacity (IEC) of sPBI polymer, synthesized by direct polycondensation in phosphoric acid for the application of proton exchange membranes. Strong hydrogen bonding among multifunctional groups established a neighborhood of interconnected hydrophobic graphene sheets and organic polymer chains. It provides hydrophobic-hydrophilic phase separation and facile proton hopping architecture. The optimized sPBI/SIGO (15 wt %) revealed 2.45 meq g(-1) IEC; 5.81 mS cm(-1) proton conductivity [120 degrees C and 10% relative humidity (RH)] and 2.45% bound water content. The maximum power density of the sPBI/SIGO-15 membrane was 0.40 W cm(-2) at 160 degrees C (5% RH) and ambient pressure with stoichiometric feed of H-2/air. This recommends that sPBI/SIGO composite membranes are compatible candidate for HT-PEMFCs. (c) 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47892.