Lattice Boltzmann study of water transport in stochastic porous catalyst layer towards enhanced PEMWE performance

The porous catalyst layer (CL), where the complex coupled mass, heat transfer and electrochemical reaction occurs, plays a crucial role in affecting the energy conversion efficiency of proton exchange membrane water electrolyzer (PEMWE). In this study, the lattice Boltzmann method (LBM) was introduced to study the liquid water transportation in three-dimensional CL model. The CLs were constructed using a stochastic algorithm based on the agglomerate catalyst model with varied agglomerate radius distributions. The LBM-calculated CLs absolute permeability reveals that liquid water transportation is enhanced under an average large agglomerate radius of 1 μm near the gas diffusion layer-catalyst layer interface. This design led to an 8.33 % increase in the absolute permeability compared to the CL with uniform agglomerate radius distribution. The three-dimensional PEMWE physical model incorporated with these CL structural parameters shows a 3.66 % increase in current density. These results offer important insights for realizing high performance PEMWE CL design.