TiNx based protective coatings for corrosion protection of 316L stainless steel bipolar plates under PEMWE anode-like conditions
Résumé
Proton exchange membrane water electrolyzers (PEMWE) electrochemically split the water molecules in order to produce high-purity oxygen (at the anode) and hydrogen (at the cathode). The elevated capital expenditures (capex) deriving from the use of expensive corrosion-resistant materials undermine the economic competitiveness of this technology [1]. In this contribution, we will focus on the corrosion protection of anodic 316L bipolar plates titanium nitride (TiNx) films. The thin coatings were grown by reactive magnetron sputtering and characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, atomic force microscopy, X-ray reflectivity, energy dispersive X-ray spectroscopy, electron energy loss spectroscopy and interfacial contact resistance measurements. The corrosion resistance of the TiN-coated stainless steel was evaluated ex situ using open-circuit potential monitoring and electrochemical impedance spectroscopy in dilute H2SO4 solution in a three-electrode electrochemical cell at 60-80°C. The solutions were also analyzed after the tests by inductively coupled plasma Optical Emission Spectrometry to detect the dissolution of 316L elements.
[1] M. Prestat, Corrosion of structural components of proton exchange membrane water electrolyzer anodes: A review, J. Power Sourc. 556 (2023) 232469.