Probing the Transport Properties, Electrophoretic Deposition, and Electrochemical Performance of La2-x Sm x Ce2O7 Ceramics for IT-SOFCs

Abstract

In this work, La2-xSmxCe2O7 (x = 0, 0.05, 0.10, 0.15, 0.20) powders are synthesized by the glycine-nitrate combustion method. The effects of the Sm dopant on the phase structure, microstructure, and electrical properties of La2-xSmxCe2O7 ceramics were investigated. All ceramics of La2-xSmxCe2O7 possess a disordered cubic fluorite structure. At x = 0, the materials exhibit a biphasic nature consisting of F- and C-type phases. With increasing x value, the amount of the C-type phase decreases. The La1.95Sm0.05Ce2O7 exhibits the highest ionic conductivity of 3.7 x 10(-3) S cm(-1) at 700 degrees C in a moist environment. For thin-film deposition of La1.95Sm0.05Ce2O7 via electrophoretic deposition (EPD), the suspension chemistry of La1.95Sm0.05Ce2O7 is studied. The coating parameters are optimized followed by sintering at 1450 degrees C with a thickness of approximately 9.1 mu m. The cell exhibited a maximum power density of approximately 474 and 397 mW cm(-2) at 700 and 650 degrees C, respectively. The electrochemical reaction mechanism of the cell during the operation is analyzed in view of the distribution of relaxation time analysis.