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Title: Investigation of the high-temperature redox chemistry of Sr 2Fe 1.5Mo 0.5O 6-δ via in situ neutron diffraction

We investigated crystallographic structural changes for Sr 2Fe 1.5Mo 0.5O 6-δ, an electrode material for symmetric solid oxide fuel cells. These samples were heated and cooled in wet hydrogen and wet oxygen atmospheres, to simulate the reducing and oxidizing conditions experienced under actual fuel cell operating conditions, and their structures and oxygen contents were determined using in situ powder neutron diffraction. The existence of a reversible tetragonal to cubic phase transition was established to occur between room temperature and 400 °C, both on heating and cooling in either oxygen or hydrogen. Furthermore, the oxygen content reaches a low value of 5.50(2) at 850 °C in wet hydrogen. Excellent correlations are observed between the oxygen content of the structure and the conductivities reported in the literature.
Authors:
 [1] ;  [2] ;  [2] ;  [1] ;  [3] ;  [4] ;  [1]
  1. Univ. of South Carolina, Columbia, SC (United States). Dept. of Chemistry and Biochemistry
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Neutron Sciences Directorate
  3. Univ. of South Carolina, Columbia, SC (United States). Dept. of Chemical Engineering
  4. Univ. of South Carolina, Columbia, SC (United States). Dept. of Mechanical Engineering
Publication Date:
OSTI Identifier:
1143586
DOE Contract Number:
AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Materials Chemistry. A; Journal Volume: 2; Journal Issue: 11
Publisher:
Royal Society of Chemistry
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE