How coarsening the 3D reconstruction of a porous material influences diffusivity and conductivity values

Coarsening the resolution of a 3D reconstruction is a common approach to make simulations feasible with regard to computational resources. We coarsen the reconstruction of a PEMFC cathode catalyst layer and investigate how this influences parameters such as diffusivity and conductivity. This is also an indication of how trustworthy these parameters are in the first place, because imaging itself is a coarsened representation of the real morphology. While diffusivity remains approximately constant due to the opposing behavior of bulk and Knudsen diffusivity, conductivity is strongly affected. The method introduced here is transferable to evaluate 3D reconstructions of other porous materials.