Dataset of "Performance and degradation analysis of sputter deposited thin-film platinum cathodes in PEM water electrolyzers analyzed by electrochemical impedance spectroscopy"

Proton Exchange Membrane Water Electrolyzers (PEM-WEs) are a key technology for green hydrogen production, however their large-scale deployment has been hindered by the reliance on noble metal catalysts, such as platinum (Pt) and iridium (Ir). In this study, we present a fully dry and scalable approach for fabricating ultra-low platinum-loaded cathodes for PEM-WE using only magnetron sputtering. The process involves a two-step approach: sputter-etching pre-treatment of the PEM surface to increase the catalyst dispersion and active surface area, followed by direct sputtering of Pt. We systematically investigate Membrane Electrode Assemblies (MEAs) with Pt loadings ranging from around 3.7 µgPt cm-2 to 480 µgPt cm-2, achieving significant performance improvement over the commercial electrodes, while reducing the Pt loading to half. Moreover, MEAs with Pt loadings around 20 µg cm-2 exhibited excellent initial performance of approximately 2 500 mA cm-2, but their stability proved to be a critical challenge. Comprehensive Electrochemical Impedance Spectroscopy (EIS) reveals key degradation mechanisms in Pt thin films , including insufficient lateral conductivity and catalyst detachment. This work provides valuable insights into the optimization of sputtered low-loading catalysts for the cathode of PEM-WE, and the analysis of the degradation pathways opens up a possibility to further stabilize the ultra-low catalyst loadings.