Study on Sm3+ and Er3+ Co-Doped CeO2-Based Electrolytes

Abstract

Ceria doped with aliovalent cations, such as rare earth oxides, has been considered as one of the most promising candidate electrolyte materials for intermediate temperature solid oxide fuel cells. In this study, high purity cerium nitrate, samarium nitrate and erbium nitrate salts were used to obtain ceria-based solid solutions Ce0.80Sm0.20O1.90 (SDC), Ce0.80Sm0.15Er0.05O1.90 (ESDC5), Ce0.80Sm0.10Er0.10O1.90 (ESDC10) through the cellulose templating method. Crystal structure and microstructure were characterized by means of X-ray diffraction and scanning electron microscopy, respectively. X-ray diffraction results indicate that a single-phase fluorite structure formed at a relatively low calcination temperature, 500 degrees C. The relative densities of the sintered pellets were higher than 93%. The electrical properties of doped and co-doped ceria electrolytes in the temperature range 300-750 degrees C were analyzed by using electrochemical impedance spectroscopy. The singly doped ceria at 750 degrees C showed the highest ionic conductivity with less activation energy.