Monte Carlo Investigation of Particle Properties Affecting TPB Formation and Conductivity in Composite Solid Oxide Fuel Cell Electrode-Electrolyte Interfaces

A previously-developed microstructure model of the Solid Oxide Fuel Cell (SOFC) electrode-electrolyte interface has been applied to the study of particle properties in these devices through the use of the Monte Carlo simulation method. Previous findings that have demonstrated the necessity of accounting for the gaseous phase percolation have been re-emphasized through the current investigation. In particular, the effects of three-phase percolation critically affect the dependence of TPB formation and electrode conductivity on: 1) conducting phase particle size distributions, 2) electronic:ionic conduction phase contrast, and 3) the amount of Mixed Electronic-Ionic Conductor (MEIC) included in the electrode. In particular, the role of differing percolation effectiveness between electronic and ionic phases has been shown to counteract and influence the role of the phase contrast. Porosity, however, has been found to not be a significant factor for the range studied, but does not obviate the necessity of modeling the gas phase. In addition, the current work has investigated the inconsistencies in experimental literature results concerning the optimal particle size distribution. It has been found that utilizing smaller particles with a narrow size distribution is the preferable situation for electrode manufacturing. These findings stress the property-function relationships of fuel cell electrode materials.