Coated Stainless Steel Bipolar Plates for Proton Exchange Membrane Electrolyzers

Given its rapid response to fluctuating currents and wide operation range, proton exchange membrane (PEM) water electrolysis is utmost suitable for generation of hydrogen from renewable power. However, it is still hindered by the high cost of the stack components compared to those used in the alkaline technology. In particular, the titanium bipolar plates (BPP) are an issue and the replacement of this metal by stainless steel is a challenge, due to the highly corrosive environment inside PEM electrolyzer stack. Herein, we coat stainless steel BPPs with 50-60 μm Ti and 1.5 μm Pt coatings by vacuum plasma spraying (VPS) and magnetron sputtering physical vapor deposition (PVD), respectively. The BPPs are evaluated at constant 1 A cm−2 for more than 1000 h. The thermally sprayed Ti coatings fully protect the stainless steel substrate during this period of time, and the Pt surface modification allows achieving a cell performance comparable to the baseline.