Polymer Electrolyte Fuel Cells Based on Phosphoric Acid-Impregnated Poly(2,5-benzimidazole) Membranes

摘要

Preparation and characterization of membranes of poly(2,5-benzimidazole) (ABPBI) (as thin as 20 Mm) for polymer electrolyteudmembrane fuel cells are reported. These membranes were prepared by solution casting and then impregnated in phosphoric acidudbaths. Their characterization included thermogravimetric analyses, conductivity measurements, Fourier transform infrared spectroscopy,udX-ray diffraction, and scanning electron microscopy. These membranes have high thermal stability and good protonudconductivity at temperatures up to 200°C (6.2 3 1022 S cm21 at 150°C and 30% relative humidity!, similar to the well-knownudcommercial polybenzimidazole (PBI). ABPBI membrane-electrode assemblies (MEAs) using commercially available E-TEK Pt/Cudelectrodes were tested in H2 /O2 cells, obtaining power densities similar to those of PBI MEAs studied here as reference atudtemperatures of up to 180°C, humidifying the reactants at room temperature