LaGaO3-based cermet for solid oxide fuel cell cathodes

A series of La0.9Sr0.1Ga0.85Mg0.15O3−δ–Ag cermets with different Ag2O contents were prepared by conventional sintering, assessing their suitability as cathode material for solid oxide fuel cell (SOFC) in combination with Sr- and Mg-doped LaGaO3 electrolytes. Ag2O is found to get dissociated at around 320 °C. The chemical compatibility between La0.9Sr0.1Ga0.85Mg0.15O3−δ–Ag (LSGM) and Ag was investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. No reaction or solid solubility between LSGM and Ag was found. Thermal expansion coefficients of the cermets were measured as a function of Ag content and were found to increase with increasing metallic content. Oxygen adsorption at the surface of the cermets could be detected.