Leveling transient and spatial gradients in planar solid oxide cells using spatially varied microstructures: A numerical study

Spatial and transient gradients of temperature, current density and gas species concentrations are expected to occur within large area planar solid oxide cells. These gradients can be detrimental to cell performance and stability. Such gradients are inherent to the geometry of the flow fields and interconnects between cells, especially at high current densities and fuel/steam utilizations in fuel cell/electrolysis modes, respectively. To reduce the extent of these gradients, additive manufacturing techniques could be employed to level the electrochemical reaction rates in the electrodes by purposefully designing the electrode active layer to have engineered property distributions. The purpose of this study is to investigate the effects of applied microstructural property gradients on spatial and transient gradients under extreme operating conditions. Modeling results suggest that by strategically varying the volume fractions of composite electrode materials, it is possible to modulate temperature, species, and current density gradients in planar solid oxide cells.