Nanostructured Proton-Conducting Membranes for Fuel Cell Applications

Composite polymer membranes based on sulfonated poly(arylene ether sulfone) (SPSU) containing benzimidazole derivatives (BIzD) and heteropolyacid for use in fuel cells were prepared. The effects of both the increment in BBIzD component and the procedure of mixing on the morphology and proton conductivity were investigated. The heteropolyacid (HPA) extracted in water decreased with the addition of BBIzD in the composite. The interactions developed among the sulfonate groups, the benzimidazole derivatives and the HPA were verified by Fourier transform infrared (FTIR). The network of interactions established in the composite membrane based on SPSU containing benzimidazole derivatives and phosphotungstic acid (HPW) in the ratio of SPSU/BBIzC4(8:1) in equivalents and SPSU/HPW(7:3) in mass resulted in a very high proton conductivity at 110 °C.