Assessment of the electronic conductivity of core-shell, Fe-doped LSGM ceramics by impedance spectroscopy

authors	Gomes, E; Mather, GC; Figueiredo, FM; Marques, FMB
nationality	International
journal	SOLID STATE IONICS
author keywords	Lanthanum gallate; Mixed conductor; Grain boundary engineering; Impedance spectroscopy; Electronic conductivity
keywords	OXYGEN PERMEATION PROPERTIES; OXIDE FUEL-CELLS; ELECTRICAL-PROPERTIES; LANTHANUM GALLATE; TRANSPORT-PROPERTIES; IONIC-CONDUCTIVITY; MIXED CONDUCTORS; SOLID-SOLUTIONS; MEMBRANES; LAGAO3
abstract	The structure, microstructure and low-temperature electrical properties of core-shell-type mixed conductors based on lanthanum gallate with Fe-doped grain boundaries are analyzed in depth. Electron probe microanalysis revealed that the iron concentration in the grain-boundary regions (shell) is below 1 at.% and their thickness is no more than 1.5 mu m. The low-temperature (<400 degrees C) electronic conductivity is enhanced by up to 2-3 orders of magnitude with respect to the corresponding undoped ceramics, as revealed by the analysis of impedance spectra combined with microstructural information. The electronic transport numbers lie in the range between 0.35 and 0.1 at 275 to 400 degrees C, decreasing at higher temperatures, where the influence of grain boundaries on the overall transport properties vanishes and the ionic conductivity increases. (C) 2011 Published by Elsevier B.V.
publisher	ELSEVIER SCIENCE BV
issn	0167-2738
year published	2011
volume	193
issue	1
beginning page	11
ending page	17
digital object identifier (doi)	10.1016/j.ssi.2011.03.006
web of science category	Chemistry, Physical; Physics, Condensed Matter
subject category	Chemistry; Physics
unique article identifier	WOS:000292946000003