The impedance of the La0.8Sr0.2MnO3 cathode/electrolyte interface for cathodes with different porosity was measured. The impedance spectra were fitted by using the developed model of the O transport at the La0.8Sr0.2MnO3 cathode/electrolyte interface. Following these measurements, the cathode was removed from the electrolyte. The contact area F and the 3-phase boundary length at the interface were estimated from scanning electron micrographs of the electrolyte surface. It was shown that the bulk diffusion of O vacancies at the interface at 950C was high enough to use the whole La0.8Sr0.2MnO3/ZrO2 contact area for O transport into the electrolyte, for microstructures with a 3-phase boundary length of less than 2μm.

Diffusion-Controlled Oxygen Transport and Stability at the Perovskite/Electrolyte Interface. M.Kuznecov, P.Otschik, P.Obenaus, K.Eichler, W.Schaffrath: Solid State Ionics, 2003, 157[1-4], 371-8