Influence of the Complex Interface between Transport and Catalyst Layer on Water Electrolysis Performance

Abstract

The interface design between anode catalyst layer (ACL) and porous transport layer (PTL) significantly influences the performance of proton exchange membrane water electrolyzers. Lately, the influence of the ACL/PTL interface on performance is more intensively investigated, including modeling approaches. Contrary to other models that apply through-plane resolved modeling, in-plane models better characterize the ACL/PTL interface. These models separate the interface into three domains: in an open pore area (P), under a contacted solid of the PTL (S), and the interfacial point between the pore and solid (S│P). In our work, we focused on the behavior of the model in the kinetic region, in which no two-phase behavior is to be expected. Consequently, we apply a one-phase model as the main model and a simple two-phase model for comparison. We find that for most reference samples, the one-phase model well describes polarization behavior. However, for samples with larger interfacial contact area, a two-phase model might explain the found effect better even for very low current densities. Finally, we show that the one-phase model and the simple two-phase model can be used to study the general behavior of different solid to pore ratios to guide electrode development in the future.