Ionic conductivity of Sr- and Mg-doped lanthanum gallate with La1.55Sr0.55Ga3O7+delta addition

Reference	Presenter	Authors (Institution)	Abstract
06-226	Talita Gishitomi Fujimoto	Fujimoto, T.G.(Instituto de Pesquisas Energéticas e Nucleares); Muccillo, E.N.(Instituto de Pesquisas Energéticas e Nucleares); Carvalho, L.A.(Instituto de Pesquisas Energéticas e Nucleares);	Sr- and Mg-doped lanthanum gallates are solid electrolytes with ionic conductivity higher than that of the traditional yttria-stabilized zirconia. Moreover, doped lanthanum gallates exhibit wide electrolytic domain and good chemical stability. The combination of their properties turns this compound a promising candidate for application in solid oxide fuel cells operating at intermediate temperatures (550-750°C). In this work, small amounts of ${\mathrm{La}}_{1.55}{\mathrm{Sr}}_{0.55}{\mathrm{Ga}}_3{\mathrm{O}}_{7+\mathrm{\delta }}$ was added to doped lanthanum gallate and the effects of the additive on electrical properties of the base material were investigated by the impedance spectroscopy technique. The X-ray diffraction patterns of sintered specimens show the characteristic reflections of the perovskite-type phase, along with low-intensity diffraction peaks of the commonly detected impurity phases. The impedance spectroscopy diagrams reveal the high-frequency arc due to the bulk resistivity besides a strong overlap of the grain boundary arc with that of the electrode. The grain resistivity decreases for increasing amounts of ${\mathrm{La}}_{1.55}{\mathrm{Sr}}_{0.55}{\mathrm{Ga}}_3{\mathrm{O}}_{7+\mathrm{\delta }}$.
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