Characterization of Catalyst Layer using Gas Diffusion Electrode Half-Cell system for Polymer Electrolyte Membrane Fuel Cell Hyeon Seung Jung

Abstract

Gas diffusion electrode (GDE) half-cells were introduced for evaluating the oxygen reduction reaction in the polymer electrolyte membrane fuel cell field, allowing the evaluation of high current density regions, which were difficult to measure using a rotating disk electrode, with the actual catalyst layer used in practice. However, GDE involves immersing the catalyst layer directly in the electrolyte, which leads to electrolyte diffusion into the catalyst layer, often complicating accurate performance evaluation and measurement. Moreover, since previous studies and commercial products use catalyst-coated membranes (CCMs), evaluating half-cells with the membrane is crucial as it helps bridge the gap toward single-cell development. This thesis introduces the half-electrode evaluation system (HEES), a novel GDE half-cell setup designed to evaluate CCMs under conditions that closely replicate full-cell operation. Electrochemical techniques, including polarization curves, cyclic voltammetry, CO stripping, and impedance spectroscopy, were applied with tailored protocols to evaluate ORR behavior and catalyst layer performance. The findings confirm that HEES provides detailed insights into electrode electrochemical characteristics, establishing it as an effective tool for bridging GDE half-cells and full-cell conditions