Corrosion-resistant TiZrNbTaW high-entropy alloy coatings for Ti anode polar plates of proton exchange membrane water electrolyzers

HW Zhao and R Gao and H Li and MY Ma and GX Chen and DM Zhu and MAC Berton and D Ning and A Weidenkaff and YL Li, CHEMICAL ENGINEERING JOURNAL, 523, 168835 (2025).

DOI: 10.1016/j.cej.2025.168835

Titanium has been widely used in proton exchange membrane water electrolysis (PEMWE) as a corrosion-resistant material. However, oxidation and corrosion of titanium are inevitable in the harsh working conditions of PEMWE. The high cost of protective Au and Pt noble metal coatings on titanium substrates greatly restricts the development of PEMWE. In this study, TiZrNbTaW high-entropy amorphous alloy (HEAA) coatings were explored by magnetron sputtering to serve as corrosion- resistant coatings for anode polar plate (APP) in PEMWE. The HEAA coatings were tested in 0.5 mM H2SO4 with 5 ppm F-and 0.5 M H2SO4 with 5 ppm F-, demonstrating excellent anti-corrosion compared to bare titanium and Pt coating. The protection efficiency, porosity, and charge transfer resistance of the HEAA coating reached 99.1 %, 0.06 %, and 169.0 k Omega cm2, respectively, in 0.5 M H2SO4 with 5 ppm F-. It can be inferred that the amorphous structure and durable passivation film protect from severe electrochemical corrosion. Density functional theory calculations revealed the electron-sharing effect, which strengthened the interaction between unpaired d-level electrons and improved anti-corrosion properties. The HEAA coating deposited at 350 degrees C was found to perform well in anti-corrosion tests and was applied to the APP for practical water electrolysis. The HEAA coating demonstrated good reliability during the 100-h electrolysis at 2 A cm-2, reaching interfacial contact resistances of 29.9 and 115.1 m Omega cm2 at 120 N cm-2, respectively, before and after the electrolysis. The excellent anti-corrosion properties and electrical conduction of the non-noble TiZrNbTaW HEAA coating make it a promising alternative to noble Pt coatings for PEMWE applications.

Return to Publications page