Structural, morphological, and electrical properties of doped ceria as a solid electrolyte for intermediate-temperature solid oxide fuel cells

• Published in: Journal of materials science 2015-05, Vol.50 (10), p.3781-3794
• Main Authors: Stojmenović, M., Žunić, M., Gulicovski, J., Bajuk-Bogdanović, D., Holclajtner-Antunović, I., Dodevski, V., Mentus, S.
• Format: Article
• Language: English
• Subjects: Cerium; Cerium oxides; Characterization and Evaluation of Materials; Chemistry and Materials Science; Classical Mechanics; Crystallography and Scattering Methods; Dopants; Electric properties; Electrical properties; Electrical resistivity; Electrolytes; Electrolytic cells; Fluorite; Fuel cell industry; Fuel cells; Gadolinium oxides; Glycine; Lattice parameters; Materials Science; Nanostructure; Original Paper; Oxides; Polymer Sciences; Raman spectroscopy; Rare earth compounds; Rare earth metals; Rare earth oxides; Self propagation; Sintering; Solid electrolytes; Solid Mechanics; Solid oxide fuel cells; Solid solutions; Spectrum analysis; Transmission electron microscopy
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-015-8943-y

The solid solutions of CeO 2 with one or more rare-earth oxides among Yb 2 O 3 , Sm 2 O 3 , and Gd 2 O 3 are synthesized by either modified glycine nitrate procedure (MGNP) or self-propagating reaction at room temperature (SPRT). The overall mole fraction of rare-earth oxide dopants was x  = 0.2. The characterization was committed by XRPD, TEM, BET, and Raman Spectroscopy methods. According to XRPD and Raman spectroscopy, the obtained products presented the single-phase solid solutions with basic fluorite-type CeO 2 structure, regardless on the number and the concentration of dopants. Both XRPD and TEM analysis evidenced the nanometer particle dimensions. The defect model was applied to calculate lattice parameters of single-, co-, and multi-doped solids. The sintering of the sample nanopowders was performed at 1550 °C, in air atmosphere. The sintered samples were characterized by XRPD, SEM, and complex impedance methods. The sintering did not affect the concentration ratios of the constituents. The highest conductivity at 700 °C amounting to 2.14 × 10 −2 and 1.92 × 10 −2  Ω −1  cm −1 was measured for the sample Ce 0.8 Sm 0.08 Gd 0.12 O 2−δ , synthesized by SPRT and MGNP methods, respectively. The corresponding activation energies of conductivity, measured in the temperature range 500–700 °C, amounted to 0.24 and 0.23 eV.