Towards High-Throughput Testing of Bipolar Plate Materials for Proton Exchange Membrane Water Electrolyzers: Correlative Contact Resistance and Stability Analysis.

Bipolar plates (BPP) are a major cost driver in proton exchange membrane water electrolyzers for green hydrogen production that require replacement with more cost-effective materials. However, novel materials must combine high corrosion resistance and low dissolution rates with low interfacial contact resistance (ICR). Herein, we introduce a correlative workflow for determining electrochemical dissolution using a scanning flow cell coupled on-line to an inductively coupled plasma spectrometer and ICR, utilizing a novel miniaturized ICR setup with a sample diameter of 2 mm. The applicability of the setup is demonstrated using titanium (Ti), for which the ICR is found to increase depending on the applied oxidation potential. Furthermore, automated ICR mapping across pristine Ti sheets with a platinum (Pt) coating featuring a thickness gradient reveals a pronounced ICR decrease when the Pt layer exceeds ∼3.8 ± 1.4 nmPt, while thicker Pt coatings (up to ∼80 nmPt) do not provide further improvement. These results demonstrate that ultrathin Pt coatings can already substantially reduce the ICR of titanium-based BPP materials. Our setup enables high-throughput screening of material libraries and provides a powerful tool for developing optimized PEMWE components with low ICR and high electrochemical stability.