In the present work, the binary system of (Bi 2 O 3 ) 1-x (Yb 2 O 3 ) x was investigated. For the production and stabilization of the fcc-type solid solution, small amounts of Yb 2 O 3 were doped into pure a-Bi 2 O 3 by the solid-state reactions in the doping range of 0.10 B x B 0.2. According to XRD and electrical conductivity measurements, the crystal formula of the formed d-Bi 2 O 3 was found to be Bi(III) 4-2x Yb(II) 2x O 6-x h 2?x (h: oxygen ion vacancies, VOÁÁ) and x values were in the range of 0.14 B x B 0.20 for heat treatment at 750°C. Four-probe d.c. electrical conductivity measurements showed that the studied system had an O 2-ionic-type electrical conductivity behavior. The maximum levels of the electrical conductivity were observed for 16 mol d-YSB material which had r T values: 0.316 and 0.632 X -1 cm -1 at 700 and 750°C, respectively. These materials can be used as ceramic electrolytes for solid electrolytic industrial applications.

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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 ?m. 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).

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