Methods— A Simple Method to Measure In-Plane Electrical Resistance of PEM Fuel Cell and Electrolyzer Catalyst Layers

Abstract

Optimizing the catalyst layer of polymer electrolyte membrane fuel cells and water electrolyzers requires a good understanding of its properties. The in-plane electrical resistance of the catalyst layer is a key property, which impacts the overall cell performance. In this work, we present a simple method to measure the in-plane electrical resistance of catalyst layers under various conditions based on the transfer length method. The applicability of the method was demonstrated on four examples: 1) Placing the compact setup in a climate chamber, showed that reducing the relative humidity from 95% to 40% yields a reduction of the resistivity of 15% in a fuel cell cathode catalyst layer; 2) graphitizing CNovel™ carbon support reduces the resistivity by 98% in a fuel cell cathode catalyst layer; 3) adding an electrically conductive polymer as electrode binder lowers the in-plane resistivity of a water electrolyzer anode by 50%; 4) adding IrO2-nanofibers to a low-loaded IrO2-nanoparticle anode lowers its resistivity by 60%. The broad range of applications in this work confirms the versatility of the setup enabling widespread application. The method hence contributes to an improved deconvolution of different loss mechanisms including electrical in-plane resistivity.