Morphological Analysis of Polymer Electrolyte Fuel Cell Electrode Using High Resolution X-ray Computed Tomography and Subsequent Performance Analysis

Abstract

Here we present a study on the morphology of the porous polymer electrolyte fuel cell (PEFC) electrodes as well as the individual catalyst agglomerates that assemble into the electrode structure, and how those characteristics influence fuel cell performance. The agglomerates and the porous electrode structure were three-dimensionally imaged using non-invasive and non-destructive nano-scale resolution X-ray computed tomography (nano-CT). The GDE fabricated from the same catalyst layer slurry (ink) as the imaged samples were electrochemically evaluated in a PEFC. By using the same ink batch in the two imaging steps, and in the fuel cell testing and then systematically varying ink processing, we have delineated the complex relationships between catalyst ink, electrode structure, and PEFC performance. At the higher current densities, we found that the electrode comprising smaller agglomerates performed better than the one comprising relatively larger agglomerates.