Effect of polymer molecular weight of ABPBI on membrane electrode assembly of high temperature proton exchange membrane fuel cells

Molecular weight is one of the essential parameters which can characterize the polymer features. It plays an important role in the performances of membrane electrode assembly (MEA). Poly(2, 5-benzimidazole) (ABPBI) is the simplest type of the benzimidazole polymer. It can be prepared easily by a single monomer, and the -N groups combining with acid by the hydrogen bond. It possesses high proton conductivity. In this work, different molecular weight ABPBIs were synthesized, and the ABPBIs were used to fabricate MEAs. The performances of the MEAs were studied by polarization curves and electrochemical impedance spectroscopy (EIS). The results showed when ABPBI was the least molecular weight, MEA had the best performance. Moreover, the resistances of MEA were decreased as the current density was increased. © All Rights Reserved.