Effect of Catalyst Distribution on Macroscopic MASS Transport Properties of a FUEL CELL Catalyst Electrode: Pore-Scale Modeling Approach
Аннотация
The work elucidates the effect of micro-morphology parameter. i.e. catalyst distribution, on macroscopic mass transport properties of a catalyst electrode of a PEM fuel cell. Indeed, the micro-morphology parameters have significant effect on transport properties, such as permeability, tortuosity. Pore-scale analysis of fluid flow has been done using Lattice Boltzmann method. Besides other morphological parameters, like porosity, clusterization, geometry those are common for a porous medium, the mass transport properties of a porous electrode of a fuel cell is governed by catalyst particle deposition distribution. This fact enables to control flow field inside of the most vulnerable membrane electrode assembly compartment. Redistribution of catalyst might be required to design novel MEA more robust prone to degradation processes, especially for transport application. In particular, the influence of a catalyst loading on permeability has been studied. It is explored that increasing the catalyst loading definitely improves transport parameter, but this improvement has maximum effect up to certain (ω Pt ≈0.2) value of catalyst loading. Moreover, how permeability changes depending on a distribution of the same amount catalyst towards membrane has been considered. Pore-scale simulation of different catalyst layer configuration with regards to catalyst deposition shows that redistribution of catalyst in exponential decaying towards membrane allows three times improve permeability of catalyst electrode compared to conventional/homogeneous distribution.