Electrical and microstructural characterization of La0.7Sr0.3MnO3 (LSM), Ce0.8Y0.2O2 (CY) and LSM-CY composites

Strontium-doped lanthanum manganite (LSM) has good properties that qualify it for cathode application in solid oxide fuel cells (SOFCs). Although LSM and YSZ are thermally compatible, composite cathodes made from these materials have been used instead of pure LSM. In this work, the electrical conductivity of La0.7Sr0.3MnO3 (LSM), Ce0.8Y0.2O2 (CY) and LSM-x vol.% CY (x=30 and 70) composites was investigated. The electrical conductivity of the samples was measured by the dc four-probe technique, using Pt electrodes and YSZ electron-blocking electrodes. Measurements were taken in a temperature range of 250-800 degrees C in air. The samples were also characterized by XRD and SEM. The use of two types of electrodes allowed for an evaluation of the ionic and electronic conductivity of LSM, found to be 6.3 x 10(-4) and 1.1 x 10(2) S cm(-1), respectively, at 800 degrees C. CY showed only ionic conduction of 7.2 x 10(-2) S cm(-1) at 800 degrees C. (C) 2007 Elsevier B.V. All rights reserved.