Investigation of the Impact of Sintering on SOFC Charge Transfer

Abstract

Solid oxide fuel cell electrodes are porous composites commonly produced by the sintering of powder compacts. Particle contact geometry within the electrode microstructure has been noted to impact electrode performance, particularly with respect to charge transfer. An analytical modeling concept has been applied to charge transport within the SOFC electrode microstructure using an approach similar to thermal fin analysis. This approach has the ability to account for variable cross-section solid geometry and replicates experimentally observed behavior related to SOFC electrode sintering quality. Microstructural geometries simulated by periodic structures composed of iterated base units with variable cross-section are investigated using two approaches: an axisymmetric one-dimensional analytical solution and an axisymmetric two-dimensional finite element solution. Results are cast in terms of dimensionless parameters and performance metrics that have been developed to assess the quality of SOFC electrode microstructures. Comparison of the one-dimensional and two-dimensional results demonstrates the predictive capabilities of the simplified approach.