LaGaO_3-based cermet for solid oxide fuel cell cathodes

摘要

A series of La_(0.9)Sr_(0.1)Ga_(0.85)Mg_(0.15)O_(3-delta)-Ag cermets with different Ag_2O 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 LaGa03 electrolytes. Ag_2O is found to get dissociated at around 320 deg C. The chemical compatibility between La_(0.9)Sr_(0.1)Ga_(0.85)Mg_(0.15)O_(3-delta)-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.