Quantifying porous transport Layer–Catalyst layer stress distribution for proton-exchange-membrane water electrolyzers using Finite element analysis

Abstract

Clean hydrogen from proton-exchange-membrane water electrolyzer (PEMWE) is a promising means to decarbonize hard-to-abate sectors. Reducing its cost requires designing next-generation porous transport layers (PTL), such as microporous layers (MPL) to minimize ohmic losses and enable thinner membranes. However, the interfacial contact between the PTL and the catalyst layer (CL) remains ambiguous, as surface roughness is often used as the only quantitative metric to describe this crucial interface. This study presents a powerful computational tool that quantitatively characterizes this sophisticated interface between the PTL and the membrane using 3D Finite Element Analysis (FEA) methods. The results revealed that consideration of plastic deformation is critical in the model construction, as the elastic model overestimates maximum von Mises stress up to 65%, and underestimates indentation depth by 4%, leading to conservative designs, misprediction of failure location and an unclear safety margin. Moreover, the FEA model identifies that the morphological structure of the PTL is a key design factor that mechanistically impacts the interfacial contact with the membrane, rather than the PTL thickness or flow field channel design. This indicates design flexibility for optimizing PTL thickness and channel geometry for mass transport performance, since the impact of stress and deformation on mechanical stability is negligible. Lastly, the advantages of MPL on interfacial contact have been quantitatively demonstrated via FEA model. The MPL exhibited a 36% increase in contact area, approximately three times of the commercial PTL. This explains the reduced stress and deformation experienced by the membrane when MPLs are used in PEMWE.