Crystallographic structural changes were investigated for Sr2Fe1.5Mo0.5O6−δ, an electrode material for symmetric solid oxide fuel cells. The samples of this material 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. 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.
Published in Journal of Materials Chemistry A, Volume 2, Issue 11, 2014, pages 4045-4054.
©Journal of Materials Chemistry A 2014, Royal Society of Chemistry.
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This article was first published by the Royal Society of Chemistry and can be found at http://dx.doi.org/10.1039/C3TA14913G
Bugaris, D. E., Hodges, J. P., Hug, A., Chance, W. M., Heyden, A., Chen, F., & zur Loye, N.-C. (21 March 2014). Investigation of the High-Temperature Redox Chemistry of Sr2Fe1.5Mo0.5O6-δ via In Situ Neutron Diffraction. Journal of Materials Chemistry A, 2 (11), 4045 – 4054. http://dx.doi.org/10.1039/C3TA14913G