Membranes based on sulfonated poly(aryl ether ketone) are known to be very promising materials for Proton Exchange Membrane Fuel Cells (PEMFC). Sulfonated poly(ether-ether-ketone) (SPEEK), with high sulfonation degrees (SD), present high proton conductivity. However, they lose functionality and conductivity at high temperatures and low humidity. To enhance the performance of these materials, hybrid membranes have gained considerable attention. In this work, zirconized SPEEK/phosphonated copolysilsesquioxane (CF) hybrid membranes were prepared by casting, from SPEEK (60% < SD < 70%) and 1, 5, or 10 wt. (%) zirconyl chloride solutions. The membranes were characterized by infrared spectroscopy (FTIR), X-ray diffractometry (DRX), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), proton conductivity, and scanning electron microscopy (MEV). Energy-dispersive X-ray spectroscopy (EDS) analyses confirmed the presence of Zr in spherical domains along the membrane, while DRX showed that the precipitated zirconium compounds had an amorphous character. Electrochemical impedance measurements indicated an increased proton conductivity with the addition of CF and ZrOCl2.
Fuel cells; proton exchange membranes; hybrid materials
