Diffusion controlled oxygen transport and stability at the perovskite/electrolyte interface

The impedance of the La(0.8)Sr(0.2)MnO(3) (LSM) cathode/electrolyte interface for cathodes with different porosity was measured. The impedance spectra were fitted using the developed model of the oxygen transport at the La(0.8)Sr(0.2)MnO(3) cathode/electrolyte interface. Following these measurements, the cathode was removed from the electrolyte. The contact area F and the three-phase boundary length (TPBL) At the interface were estimated from SEM micrographs of the electrolyte surface. The dependence of the interfacial electrical resistance on the microstructure is discussed. It is shown that the bulk diffusion of the oxygen vacancies at the interface at 950 degreesC is high enough to use the whole La(0.8)Sr(0.2)MnO(3)/YSZ contact area F for the oxygen transport into the electrolyte for microstructures with 2F/TPBL less than or equal to 2 mum. (C) 2002 Elsevier Science B.V. All rights reserved.