High-Resolution Mapping of the PFSA Polymer Distribution in PEFC Electrode Layers

Abstract

Perfluorosulfonic acid (PFSA) ionomer is a key component within electrode layers for the polymer electrolyte fuel cell (PEFC) since the solid electrolyte enables proton transport to the active catalyst site. Both the through-layer loading on a 100-nm length scale as well as the local film thickness distribution on a 1-nm scale of the ionomer in the porous layer structure are important to electrode performance so quantitative measurements of both properties are desired. In this paper, we present ionomer mapping measurements at both length scales using two common PEFC electrode constructions.