Synthesis and characterization of CeLaMO2 (M: Sm, Gd, Dy) compounds for solid ceramic electrolytes

Abstract

In this study, pure CeO2 and Ce0.85La0.10M0.05O2 (M: Sm3+, Gd3+, Dy3+) solid electrolytes were synthesized using the sol-gel method and sintered at 1350°C for 12 h. X-ray diffraction (XRD) was used for crystal structure characterization of the ceramic solid electrolytes. After sintering, all prepared solid electrolytes were indexed to be cubic crystal lattices. The thermal properties of the prepared samples were investigated by thermogravimetric (TG) and differential thermal analysis (DTA) methods. The surface properties of the grain structure of the ceramic solid electrolytes were evaluated by scanning electron microscopy (FE-SEM) confirming the average grain size of about 1 μm. The electrochemical impedance spectroscopy technique was used to investigate AC electrical properties of prepared solid electrolytes. The conductivity values at 750°C of the Ce0.85La0.10Sm0.05O2, Ce0.85La0.10Gd0.05O2 and Ce0.85La0.10Dy0.05O2 and pure CeO2 were found to be 1.10 × 10−3 S/cm, 3.05 × 10−4 S/cm, 8.85 × 10−4 S/cm and 8.44 × 10−10 S/cm, respectively. The characterization results showed that the La-Sm co-doped CeO2 sample can be used as a ceramic electrolyte in intermediate temperature solid oxide fuel cells (IT-SOFC).

Keywords

• co-doped ceria
• structure
• critic ionic radius
• oxygen ion conductivity