Physicochemical compatibility of CGO fluorite, LSM and LSCF perovskite electrode materials with La2MO2O9 fast oxide-ion conductor

The reactivity of typical electrode materials for solid oxide fuel cells, namely La0.6Sr0.4Co0.2Fe0.8O3-delta (LSCF), La0.8Sr0.2MnO3-delta (LSM) and Ce0.9Gd0.1O1.95 (CGO), with fast oxide-ion conductor La2Mo2O9 is thoroughly studied using X-ray diffractometry. Modifications in the materials diffraction patterns and occurrence of impurity diffraction peaks are evidenced in LSCF and LSM above 700-800 degrees C. They are interpreted in terms of cationic migrations from one material phase to the other (typically strontium depletion/substitution), and subsequent formation of subsidiary phases (for instance strontium molybdate). With CGO no reactivity is observed up to 1000 degrees C. For all three electrode materials the thermal expansion coefficient (TEC) is measured from X-ray thermodiffractograms and compared to that of La2Mo2O9. (c) 2005 Elsevier SAS. All rights reserved.