Electrical properties of ceria/carbonate nanocomposites

• Published in: Journal of alloys and compounds 2012-08, Vol.532, p.109-113
• Main Authors: Ristoiu, Tania, Petrisor, Traian, Gabor, Mihai, Rada, Simona, Popa, Florin, Ciontea, Lelia
• Format: Article
• Language: English
• Subjects: Alloys; Blue shift; Carbonates; Cerium oxide; Chemical synthesis; Composite materials; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Diffusion in solids; Electric potential; Electronic transport in condensed matter; Exact sciences and technology; Ionic conduction; Mixed conductivity and conductivity transitions; Nanocomposites; Optical spectroscopy; Physics; Self-diffusion and ionic conduction in nonmetals; SEM; Solid oxide fuel cells; Temperature dependence; Thermal analysis; Transport properties of condensed matter (nonelectronic)
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2012.03.098

► Preparation and characterization of a CeO2/Na2CO3 nanocomposite. ► Evidence of the enhancement of electrical conduction of the composite. ► Demonstration of dominant percolative interface conduction mechanism. Ceria-based composites are developed as potential electrolytes for intermediate solid oxide fuel cell applications and a better understanding of the ionic conduction mechanism serves this purpose. Ceria-based composites were produced by several processing routes using a ceria-based ceramic host (Sm, Gd doped ceria) and various Na and Li carbonates. Simple ceria/carbonate two-phase nanocomposites were synthesized by the carbonate precipitation method followed by a thermal treatment. The decomposition course of the precursor, the thermal stability, morphology and the composite formation mechanism were studied by thermogravimetric–differential thermal analyses (TG–DTA), IR, UV, SEM and XRD analyses. The conductivity temperature dependence in the 300–800°C temperature range, performed on composite pellets, exhibits conductivity values one-two higher magnitude order and a lower activation energy of 0.809±0.001eV, with respect to 1.693±0.005eV for pure ceria obtained under the same conditions. This enhancement of the composite conductivity, corroborated with the blue shift of the gap energy, as deduced from the UV spectra, was attributed to the oxygen ion transport through an interface mechanism between the two phases of the ceria/carbonate composite.