A two-dimensional network PBI membrane cross-linked through metal Ce-ligand bond for the high-temperature proton exchange membrane fuel cells

Here, A two-dimensional network polybenzimidazole (PBI) membrane was synthesized through metal Ce-ligand bond between the cerium trifluoromethanesulfonate and the modified PBI, which was synthesized by introduce the 2,2′-biquinoline-4,4′-dicarboxylic acid and 2,2′-bipyridine-4,4′-dicarboxylic acid into traditional m -PBI membranes. The two-dimensional network PBI membrane (named CO-PBI) demonstrates enhanced toughness, phosphoric acid (PA) retention, chemical stability. Upon PA doping, the CO-PBI membrane achieves a tensile strength of 42.42 MPa, a proton conductivity of 0.162 S cm −1 at 160 °C, and a power density of 484.77 mW cm −2 which is representing a 2.45 times enhancement compared to the pristine PBI membrane. This study presents a viable structural design framework to comprehensively improve the performance of PA-PBI proton exchange membranes.