A grid-based percolation model for the electrode of the solid oxide fuel cell

Abstract

ABSTRACT For solid oxide fuel cells, the percolation model is a mathematical tool to predict the percolating properties (percolating probability, total and effective three-phase boundaries (TPB), etc.) of an electrode. Here, a grid-based 3D percolation model is proposed. Compared with the traditional analytic percolation models, it is more comprehensive because it additionally accounts for the active TPBs near the electrolyte–electrode interface and the percolating probability of pore. Moreover, compared with the pixel-based 3D reconstruction models, this model consumes much less time and memory, which makes large domain size simulation efficient. To characterize the experimental repeatability and reproducibility of the percolating properties among numerous electrodes, distribution profile is introduced to the simulation where quantities of numerical samples are generated and counted. Our model results match well with the reported ones. The optimal porosity is 30%–35% for our studied cases. Our model suggests that the pore percolating probability could not be neglected in the percolation simulations. Finally, domain size effect is investigated. TPB density becomes converged when the domain. size is at least 12 times the particle diameter. This model provides a practical and flexible access to the large domain simulations of the electrode percolating properties.