Investigations of the LaGa1-xNixO3-δK (x≤0.50) system in the scope of SOFC's:: synthesis and physical characterizations

The preparation and densification (similar to 95 %) of ceramics of the new solid solution LaGa1-xNixO3-delta have been carried out for x less than or equal to 0.50. The chemical analysis of the materials shows that both the oxygen non-stoichiometry amount (delta) and the electron carrier concentration increase with the substitution of nickel for gallium. Whereas LaGaO3 is an insulator, the Ni-doped phases are semi-conducting and behave as a metal for the highest nickel contents. The dilatometric features versus temperature show these materials to be mechanically compatible with the electrolyte La0.90Sr0.10Ga0.80Mg0.20O2.85. In addition their chemical composition does not change at high temperature. All these characteristics make these materials good candidates as cathodes for solid oxide fuel cells. (C) Academie des sciences/Elsevier, Paris.