Toward Low-Pt PEMWE Components: Determining the Minimum Thickness of Pt Protection Coatings on Titanium BPP.

The harsh anodic environment in proton exchange membrane water electrolyzers (PEMWEs) necessitates surface modification of titanium bipolar plates (BPPs) to prevent corrosion-induced ion release and formation of non-conductive oxides. Platinum coatings are a commonly used approach, providing electrically conductive corrosion protection. However, their limited availability and high material cost highlight the need to reduce Pt utilization for large-scale application. Therefore, this study systematically investigates the electrochemical performance and durability of nanometer-scale Pt coatings on grade 2 Ti substrates, aiming to minimize film thickness while maintaining functional integrity. Using a comprehensive set of high-resolution characterization techniques, this work provides detailed insights into the interplay between Pt film thickness, coating defects, and substrate degradation. Overall, the results demonstrate that Pt coatings with a thickness of about 24 nm (≈57 μg cm-2 Pt loading) can effectively protect titanium BPP, highlighting that nanometer-thin coatings preserve performance while enabling a significant reduction in Pt usage for PEMWE bipolar plate design.