Tailoring the electrode/porous transport layer interface by assembling parameters in PEM water electrolyzers

The interface between the anode porous transport layer (PTL) and the catalyst-coated membrane (CCM) plays a crucial role in determining the efficiency of the proton exchange membrane water electrolyzer (PEMWE). Notably, clamping pressure emerges as a crucial factor that affects this interfacial contact. This work focuses on the assembling parameters contributing to variations in clamping pressure between the PTL and the CCM in PEMWE. We systematically examine the impact of PTL compression, torque, and CCM expansion caused by water uptake on PEMWE performance. The assembling parameters determined in this study—0% PTL compression, 3.5 N m torque, and CCM expansion—satisfy the performance requirements for PEMWE while maintaining the integrity of the electrode. Electrochemical diagnostics, combined with pressure-sensitive paper analyses, demonstrate that CCM expansion provides a sufficient conductive pathway between the catalyst layer (CL) and PTL, thereby achieving lower contact resistance. Physical characterization analysis demonstrates that the CCM expansion provides a more uniform clamping pressure, further protecting the CL from damage and resulting in better performance and durability.