Defect Chemistry, Electrical Properties, and Evaluation of New Oxides Sr2CoNb1-xTixO6-delta (0 <= x <= 1) as Cathode Materials for Solid Oxide Fuel Cells
authors Azcondo, MT; Yuste, M; Perez-Flores, JC; Munoz-Gil, D; Garcia-Martin, S; Munoz-Noval, A; Orench, IP; Garcia-Alvarado, F; Amador, U
nationality International
journal CHEMSUSCHEM
author keywords cathode; cobaltite; perovskite; solid oxide fuel cells; x-ray absorption spectroscopy
keywords MAGNETIC-PROPERTIES; OXYGEN REDUCTION; MICROSTRUCTURE; PEROVSKITES; ELECTRODES; SPECTROSCOPY; MECHANISM; IMPEDANCE; SERIES; SOFC
abstract The perovskite series Sr2CoNb1-xTixO6-delta (0 <= x <= 1) was investigated in the full compositional range to assess its potential as cathode material for solid oxide fuel cell (SOFC). The variation of transport properties and thus, the area specific resistances (ASR) are explained by a detailed investigation of the defect chemistry. Increasing the titanium content from x = 0-1 produces both oxidation of Co3+ to Co4+ (from 0 up to 40%) and oxygen vacancies (from 6.0 to 5.7 oxygen atom/formula unit), although each charge compensation mechanism predominates in different compositional ranges. Neutron diffraction reveals that samples with high Ti-contents lose a significant amount of oxygen upon heating above 600 K. Oxygen is partially recovered upon cooling as the oxygen release and uptake show noticeably different kinetics. The complex defect chemistry of these compounds, together with the compositional changes upon heating/cooling cycles and atmospheres, produce a complicated behavior of electrical conductivity. Cathodes containing Sr2CoTiO6-delta display low ASR values, 0,13 Omega cm(2) at 973 K, comparable to those of the best compounds reported so far, being a very promising cathode material for SOFC.
publisher WILEY-V C H VERLAG GMBH
issn 1864-5631
year published 2017
volume 10
issue 14
beginning page 2978
ending page 2989
digital object identifier (doi) 10.1002/cssc.201700648
web of science category Chemistry, Multidisciplinary; GREEN & SUSTAINABLE SCIENCE & TECHNOLOGY
subject category Chemistry; Science & Technology - Other Topics
unique article identifier WOS:000406052000017
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journal impact factor 7.411
5 year journal impact factor 7.575
category normalized journal impact factor percentile 89.341
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