The effect of doping with transition metals upon the oxide-ion conductivity of La0.8Sr0.2Ga0.8Mg0.2O3 was investigated. It was found that doping with Co was effective in increasing the oxide ion conductivity; especially at low temperatures. The conduction could be generally improved by doping with transition metal cations. However, the theoretical electromotive force was almost attained by an H2-O2 cell, with Co-doped La0.8Sr0.2Ga0.8Mg0.2O3, for Co concentrations of less than 10mol% on Ga sites. The diffusion characteristics of the oxide ion in the 7mol%Co-doped material were also investigated by using the 18O tracer method. Because the diffusion coefficient which was measured using this method was almost the same as that estimated from electrical conductivity measurements, it was concluded that conduction in the Co-doped material was almost ionic. It was suggested that the improved oxide-ion conductivity, following Co-doping, was due to an enhanced mobility of the oxide ions.

Improved Oxide Ion Conductivity of Co Doped (La,Sr)(Ga,Mg)O3 Perovskite Type Oxide. T.Ishihara, T.Akbay, H.Furutani, Y.Takita: Solid State Ionics, 1998, 113-115, 585-91