# Innovative Method for Reliable Measurement of PEM Water Electrolyzer Component Resistances

## TL;DR

This paper introduces a new method using PCB-based probes to accurately measure sheet resistance in PEM water electrolyzer components, improving design and performance.

## Contribution

A novel probe design and image-processing method for reliable sheet resistance and thickness analysis in PEM electrolyzer components.

## Key findings

- The PCB-based probe enables local resistance mapping across ten distances from 250 µm to 2500 µm.
- Image processing provides thickness distribution of catalyst layers, aiding in-plane resistivity analysis.
- The method supports faster material integration and better alignment between electrode engineering and cell testing.

## Abstract

Understanding the sheet resistance of porous electrodes is essential for improving the performance of polymer electrolyte membrane (PEM) water electrolyzers and related technologies. Despite its importance, existing methods often fail to provide reliable and comprehensive data, especially for porous materials with complex morphologies and non‐uniform thicknesses. This study introduces a robust and straightforward method for determining the sheet resistance of porous electrodes using a novel probe concept based on industrial printed circuit board (PCB) technology. This probe measures resistance across ten distances, ranging from 250 µm to 2500 µm, enabling local mapping of resistance. The study focuses on the sheet resistance of key components in PEM water electrolyzers, including the gas diffusion layer (GDL), porous transport layer (PTL), and catalyst layers deposited on a membrane. Additionally, an image‐processing‐based method is presented to obtain the thickness distribution of the studied catalyst layers, facilitating a detailed analysis of the electrical in‐plane resistivity with thickness variations. Overall, this methodology has the potential to expedite material integration and bridge the gap between electrode engineering and single‐cell testing, thereby advancing the development of PEM water electrolyzers.

Accurate sheet resistance measurements are essential for optimizing porous electrode design in polymer electrolyte membrane water electrolyzers. The authors present a reliable method using a novel probe concept based on industrial printed circuit board technology. Furthermore, the authors use image processing to extract the thickness distribution of the catalyst layer, which is discussed in relation to the in‐plane electrical resistivity.