Evaluation of La0.8Sr0.2Cu1-xMnxOd Double Perovskite for Use in SOFCs

Abstract

Compounds with the general formula La0.8Sr0.2Cu1-xMnxO3 were prepared by the citrate route. A solid solution region containing hexagonal perovskite phase, was formed when 0.6{less than or equal to}x{less than or equal to}1, in which oxygen stoichiometry in air changes from oxygen deficiency to oxygen excess with Mn doping. The temperature dependence of electrical conductivity changes from metallic- like behavior in La0.8Sr0.2CuO3-d to semiconducting type in La0.8Sr0.2MnO3+d. Mn doping resulted in a decrease in the conductivity (with the minimum at 40% Mn doping), whereas the thermal expansion coefficient decreased linearly with x. A defect model for the mixed Cu-Mn perovskite is proposed and related to its physical and electrochemical properties.