Title

Structural Characterization Combined with the First Principles Simulations of Barium/Strontium Cobaltite/Ferrite as Promising Material for Solid Oxide Fuel Cells Cathodes and High-Temperature Oxygen Permeation Membranes

Authors

Authors

S. Gangopadhayay; T. Inerbaev; A. E. Masunov; D. Altilio;N. Orlovskaya

Comments

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Abbreviated Journal Title

ACS Appl. Mater. Interfaces

Keywords

Perovskite structure; vacancy ordering; intermediate spin state; density; functional theory; Jahn-Teller distortion; PEROVSKITE-TYPE OXIDES; ION CONDUCTIVITY; PERMEABILITY; BA0.5SR0.5CO0.8FE0.2O3-DELTA; PERFORMANCE; STOICHIOMETRY; DIFFRACTION; EXCHANGE; CRYSTAL; SURFACE; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary

Abstract

Mixed ionic-electronic conducting perovskite type oxides with a general formula ABO(3) (where A = Ba, Sr, Ca and B = Co, Fe, Mn) often have high mobility of the oxygen vacancies and exhibit strong ionic conductivity. They are key materials that find use in several energy related applications, including solid oxide fuel cell (SOFC), sensors, oxygen separation membranes, and catalysts. Barium/strontium cobaluite/ferrite (BSCF) Ba(0.5)Sr(0.5)Co(0.8)Fe(0.2)O(3-delta) was recently identified as a promising candidate For cathode material in intermediate temperature SOFCs. In this work, we perform experimental and theoretical study of the local atomic structure of BSFC. Micro-Raman spectroscopy was performed to characterize the vibrational properties of BSCF. The Jahn-Teller distortion of octahedral coordination around Co(4+) cations was observed experimentally and explained theoretically. Different cations and oxygen vacancies ordering are examined using plane wave pseudopotential density functional theory. We find that cations are completely disordered, whereas oxygen vacancies exhibit a strong trend for aggregation in L-shaped trimer and square tetramer structure. On the basis of our results, we suggest a new explanation for BSCF phase stability. Instead of linear vacancy ordering, which must cake place before the phase transition into brownmillerite structure. the oxygen vacancies in BSCF prefer to form the finite clusters and preserve the disordered cubic structure. This structural feature could be found only in the first-principles simulations and can not be explained by the effect of the ionic radii alone.

Journal Title

Acs Applied Materials & Interfaces

Volume

1

Issue/Number

7

Publication Date

1-1-2009

Document Type

Article

Language

English

First Page

1512

Last Page

1519

WOS Identifier

WOS:000268310800022

ISSN

1944-8244

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