Engineered cathodes for high performance SOFCs

Computational design analysis of a high performance cathode is a cost-effective means of exploring new microstructure and material options for solid oxide fuel cells. A two-layered porous cathode design has been developed that includes a thinner layer with smaller grain diameters at the cathode/electrolyte interface followed by a relatively thicker outer layer with larger grains at the electrode/oxidant interface. Results are presented for the determination of spatially dependent current generation distributions, assessment of the importance of concentration polarization, and sensitivity to measurable microstructural variables. Estimates of the electrode performance in air at 700 °C indicate that performance approaching 3.1 A/cm2 at 0.078 V is theoretically possible. The limitations of the model are described, along with efforts needed to verify and refine the predictions. The feasibility of fabricating the electrode configuration is also discussed.