Replacing Titanium Components in Proton Exchange Membrane Electrolysers

Titanium-based bipolar plates and Porous Transport Layers (PTLs) currently dominate the cost of Proton Exchange Membrane Water Electrolysis (PEMWE) stacks. Replacing titanium with steel for these components would significantly enhance the cost-efficiency of PEMWE. How-ever, application of stainless-steel components in PEMWE requires functional protective coat-ings, to avoid dissolution of cations (i.e., iron leaching) and to avoid an increase in contact resistance in the locally acidic aqueous environment. This thesis investigates the replacement of expensive titanium components in PEMWE with cost-effective stainless-steel alternatives and is part of the ANR/FNS Franco-Swiss project PROTIS (Films minces d’oxyde de titane sous-stoechiométrique pour la protection de couches de transport poreuses dans les électro-lyseurs PEM). Three key experiments are conducted to assess the impact of different coatings on the conductivity and performance of the PTLs. The interfacial contact resistance of various coatings deposited on titanium PTLs is measured, providing insights into their electrical con-ductivity and contact resistance. Moreover, a baseline performance of an uncoated stainless-steel PTL in PEMWE conditions is evaluated, highlighting its rapid degradation and the need for protective coatings. And finally, the performance of a Titanium Carbide (TiC) coated Tita-nium PTL working under anodic conditions in PEMWE is evaluated. The findings underscore the importance of PTL coatings in optimizing electrical performance and highlight the potential of TiC coating as a solution for improving the performance of stainless-steel PTLs. The results provide valuable insights into the selection and evaluation of suitable coatings for stainless-steel components in PEMWE systems, contributing to the advancement of the PROTIS project.