Multiscale study on the mechanical behaviour of catalyst layer under tensile and humidity cyclic loading

The durability and life of proton exchange membrane fuel cells (PEMFCs) decrease as the mechanical damage of the catalyst layer (CL) is aggravated due to mass and electronic transport constraints. Owing to the challenge of real-time monitoring of internal stress and microstructure changes through experiments, developing an effective modelling technique to capture the onset of cracks and delamination is extremely urgent. For this purpose, this work focused on probing the effect of stress concentration regions on the mechanical behaviour of CL under tensile and humidity cyclic loading. Based on the measurement of adhesive force between Pt/C and Nafion, we constructed an interfacial model through molecular dynamics simulation and correlated it with the cohesive zone model in the micro-mechanical model. Finite element simulation was employed to predict the stress–strain response and onset of interface debonding. Some results have shown good agreement with experimental data from the literature. This model induced by interfacial strength, porosity, and ionomer expansion curve can be used to examine the damage degree of CL during the PEMFC durability testing process.