Hydrogen production by electrolysis offers significant advantages over established and more common processes such as steam reforming with regard to CO2 emissions, in particular through the use of electrical energy from renewable sources and the establishment of a decentralized supply structure. The advantages of PEM (proton exchange membrane) electrolysis include high power density, scalability, and the high purity of the produced hydrogen. However, so far the manufacturing of the PEM electrolyzers is realized only on small scale, which makes the widespread use difficult and is a main cost driver for electrolyzer systems.

In the scope of the publically funded lead project H2Giga, a series of manufacturing processes are developed for industrial scale-up production of PEM electrolyzer components, in particular the bipolar plates (BPP) and the porous transport layers (PTL). Base materials like stainless steel are used that can be processed at a low cost but need protective coatings to withstand the highly corrosive conditions during electrolysis, especially at the anode side of each cell.

In our approach, these coatings are produced by electroplating, and their protective properties are investigated by electrochemical and surface characterization techniques. Precious metals (e.g. gold, platinum) are promising due their good stability at high anodic potentials and low pH values. However, nickel alloys, especially tin-nickel, could offer a cost-effective alternative. An improved stability of the tin-nickel alloy is observed above +1.5 V vs. NHE which can be attributed to the formation of an oxide layer. The coating systems showing the best results are investigated further in a multi-cell stack setup.