Insights into CCM production with low iridium loading for PEM water electrolysis

Reducing the iridium loading in catalyst-coated membranes (CCM) for PEM electrolysis iscrucial to lowering manufacturing costs while achieving established targets (SRIA, DoE, etc.) regarding loading, performance, and degradation rates. In this study, we produced catalyst layers with a loading of 0.1 mgIr/cm² using a conventional, scalable slot-die coating method and characterized the CCMs extensively both ex-situ (XRF, SEM-EDX, etc.) and in-situ (Conditioning, UI characteristics, EIS, etc.). In-situ variations included different PTL variants on anode and cathode as well as a variety of conditioning protocols. Based on the findings, additional microporous transport layers (MPL) were developed and produced using screenprinting methods to improve the electrical interface between the catalyst layer and the test cell. A degradation study, conducted over more than 150 h, showed that the interface between the catalyst layer and the porous transport layer is crucial for optimizing performance with low-loading CCMs and for developing specialized conditioning protocols. This study demonstrates how scalable printing methods can be employed for the production and characterization of low-Ir electrodes with 0.1 mgIr/cm². This marks a significant leap forward to next-generation cell designs aimed at achieving future SRIA and DoE targets in PEM electrolysis. Furthermore, our study provides a comprehensive technical overview from scalable production methods to long-term degradation analysis.