Effects of Ionomer Carbon Ratio and Ionomer Dispersity on the Performance and Durability of MEAs

Membrane-electrode assemblies (MEAs) are fabricated using different catalysts and ionomers, in order to investigate the effects of these factors on the performance and stability of the polymer electrolyte membrane fuel cell (PEMFC). Platinum catalysts with different degrees of graphitization in the carbon support (less graphitized: Tanaka, more graphitized: RTX) are used. Perfluorosulfonic acid polymer-based ionomers with water-based or organic solvent-based solvents are also prepared as binders for the electrode. The optimum composition of catalyst and ionomer is identified based on the results of cyclic voltammetry, electrochemical impedance spectroscopy, single cell performance, and long-term durability tests. Tanaka catalyst and water-based ionomer show the best performance and durability. In addition, the ionomer to carbon (I/C) weight ratio affects the fuel cell performance, and the optimum value is I/C = 1 for both water-based and organic solvent-based ionomers.