Enhanced Ionic Conductivity in Nanostructured, Heavily Doped Ceria Ceramics

Authors


  • The present work was supported by Fundación YPF (Repsol YPF Award 2003) and Agencia Nacional de Promoción Científica y Tecnológica (Argentina, PICT No. 14268). We thank Dr. Patricia Bozzano (CAC, CNEA), Alejandro Fernández (DEICOR, CITEFA), and Rodolfo Kempf (CAC, CNEA) for their assistance during the TEM study, the SEM observations, and the density measurements, respectively. M.G.B. thanks CONICET and Fundación YPF for his PhD fellowship. Supporting Information is available online from Wiley InterScience or from the author.

Abstract

The electrical properties of nanostructured, heavily yttria- or samaria-doped ceria ceramics are studied as a function of grain size using electrochemical impedance spectroscopy (EIS). A remarkable enhancement in the total ionic conductivity of about one order of magnitude is found in nanostructured samples, compared with the intrinsic bulk conductivity of conventional microcrystalline ceramics. This effect is attributed to the predominance of grain-boundary conduction in the nanostructured materials, coupled with an increase in the grain-boundary ionic diffusivity with decreasing grain size.

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