Mixed conductivity, thermal expansion and defect chemistry of A-site deficient LaNi(0.5)Ji(0.5)O(3-delta)
authors Yakovlev, S; Kharton, V; Yaremchenko, A; Kovalevsky, A; Naumovich, E; Frade, J
nationality International
journal JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
author keywords defects; thermal expansion; ionic conductivity; perovskites; membranes; transition metal oxides
keywords PEROVSKITES; STABILITY; CONDUCTORS; TRANSPORT; METHANE; OXIDES
abstract This work is focused on the analysis of defect chemistry and partial electronic and oxygen ionic conductivities of A-site deficient La1-xNi0.5Ti0.5O3-delta (x = 0.05 and 0.10). The orthorhombic-to-rhombohedral phase transition was monitored by means of dilatometry and high-temperature X-ray diffractometry. The average thermal expansion coefficients vary in the range (8.5-13.0) x 10(-6) K-1, increasing with temperature and A-site deficiency. The ion transference numbers determined by the Faradaic efficiency measurements are lower than 0.1% at 900-975 degrees C in air. Activation energies of the oxygen ionic conductivity at 897-977 degrees C are 430 and 220 kJ/mol for x = 0.05 and 0.10, respectively. Atomistic simulation demonstrated high stability of ternary defect clusters formed by the vacant sites in the A-sublattice, oxygen vacancies and W, cations, which leads to a very low level of mixed conductivity. (c) 2007 Elsevier Ltd. All rights reserved.
publisher ELSEVIER SCI LTD
issn 0955-2219
year published 2007
volume 27
issue 13-15
beginning page 4279
ending page 4282
digital object identifier (doi) 10.1016/j.jeurceramsoc.2007.02.134
web of science category Materials Science, Ceramics
subject category Materials Science
unique article identifier WOS:000248822800150
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journal impact factor 3.794
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