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−δ (LSCF), La0.8Sr0.2MnO3−δ (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 °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 °C. For all three electrode materials the thermal expansion coefficient (TEC) is measured from X-ray thermodiffractograms and compared to that of La2Mo2O9.