Preparation and properties of lanthanum (La) and indium (In) co-doped ceria system for IT-SOFC

Abstract

The different compositions of La3+ and In3+ co-doped ceria have been prepared by a citric acid-nitrate sol-gel method. All the compositions with general formula Ce0.85La0.15-xInxO1.925(CLI) have the same concentration of total oxygen vacancies. The results of the lattice parameter calculated by the hard sphere model are consistent with those of experimental data. All the samples sintered at 1350 °C have the relative density more than 96%. The relative density and grain size of all the sintered pellets increase with increasing In3+ concentration. Electrochemical analysis indicates that grain conductivity of Ce0.85La0.15-xInxO1.925 (x = 0.01~0.03) is pretty much the same with increasing content of In, while the grain boundary conductivity decreases with increasing content of In. Moreover, La3+ and In3+ co-doped exhibits higher ionic conductivity and lower activation energy as compared with La singly doped ceria. The maximum power density of based on the CLI1 cells co-fired at 1350 °C can reach 635 mW cm−2 at 700 °C.