Double-filler composite sulfonated poly(aryl ether ketone) membranes with graphite carbon nitride and graphene oxide as polyelectrolyte for fuel cells

Composite polymer electrolyte membranes are exhibiting their bright prospect especially in the field of fuel cell now. We prepared a series of double-filler composite proton exchange membranes from sulfonated poly(aryl ether ketone)s (SPAEK), graphene oxide (GO) and graphite carbon nitride (g-C3N4) with the total filler loading of 0.75 wt%. Facile solution blending provides homogeneous, strong and flexible composite SPAEK/GO/g-C3N4 membranes readily. Characterizations and measurements including membrane morphology, water absorption and dimensional swelling, thermal and mechanical properties, chemical and electrical performance are investigated in detail. Both GO and g-C3N4 nano-fillers can offer extra proton hopping sites via the H2N…HO3S interactions and hydrogen bond networks, which promote the proton conduction and membrane stability. Attributing to the interactions between the two nano-fillers and their interactions with SPAEK polymers, the double-filler compositing system exhibits better physicochemical stability, higher proton conductivity than the corresponding single-filler ones. The SPAEK/GO/g-C3N4(2/2) membrane shows the proton conductivity of 228 mS/cm@90 °C and power output of 675 mW/cm2@80 °C in a H2/O2 fuel cell. This work provides a significative way in the development of multi-component composite polymer electrolyte membranes applied for fuel cells.