Effect of Ionomer Binder on Performance and Durability of Catalyst Layers

Abstract

Energy conversion devices often needs movement of ions between two electrodes, i.e., anode and cathode. Ions reached in front of electrodes should be transported within electrodes to participate in anodic and cathodic reactions. Pathway for ions is normally in an aqueous phase. Regardless, the introduction of any aqueous phase in energy conversion devices causes many problems during fabrication, operation, maintenance, and so on. Thus, much efforts have been devoted to develop quasi-solid electrolytes such as gel polymer, ion exchangeable polymers, impregnation of ions in porous matrix and so on. Among the candidates, ion exchangeable polymers are quite often chosen as ion conducting media for energy conversion devices. The technique to introduce ion exchangeable polymers within electrodes for oxidation and reduction reactions is to solidify catalyst inks consisting of electrocatalyst, dispersion of ion exchangeable polymers, controlling solvents and additives by evaporation of all solvents in catalyst inks. Ion exchangeable polymers could be dispersed in various solvents. It causes different shapes of ion exchangeable polymers in solvents, for instance, cylindrical rods, a less-defined large particles, coils and so on. Such different types of ion exchangeable polymers form distinguished structure catalyst layers. In this study, the effect of solvents dispersing ion exchangeable polymers on the performance and durability of catalyst layers was investigated. Electrochemical characterization such as I-V polarization, cyclic voltammetry, impedance and so on and microscopic characterization such as SEM and TEM were carried out to evaluate the performance and durability of catalyst layers. Acknowledgement This work was supported by the New and Renewable Energy of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea (No. 20173010032100).