Hexagonal perovskite related oxide ion conductor Ba3NbMoO8.5: phase transition, temperature evolution of the local structure and properties

Chambers, Matthew S.; McCombie, Kirstie S.; Auckett, Josie E.; McLaughlin, Abbie C.; Irvine, John T.S.; Chater, Philip A.; Evans, John S.O.; Evans, Ivana Radosavljevic

Abstract

Ba3NbMoO8.5 has recently been demonstrated to exhibit competitive oxide ion conductivity and to be stable under reducing conditions, making it an excellent potential electrolyte for solid oxide fuel cells. We report here the first investigation of the local structure in Ba3NbMoO8.5, carried out using variabletemperature neutron total scattering and pair distribution function (PDF) analysis. This work reveals a significant degree of disorder in the material, even at ambient conditions, in both the cation and the anion arrangements and suggests the prevalence of the five-fold Nb/Mo coordination. In addition, high resolution powder X-ray diffraction data indicate that the temperature-dependent structural changes in Ba3NbMoO8.5 are due to a first order phase transition, and reveal a previously unreported effect of thermal history on the room-temperature form of the material. PDF modelling shows that Ba3NbMoO8.5 has an essentially continuous oxygen distribution in the ab plane at 600 C which leads to its high oxideion conductivity.

Citation

Chambers, M. S., McCombie, K. S., Auckett, J. E., McLaughlin, A. C., Irvine, J. T., Chater, P. A., …Evans, I. R. (2019). Hexagonal perovskite related oxide ion conductor Ba3NbMoO8.5: phase transition, temperature evolution of the local structure and properties. Journal of Materials Chemistry A: materials for energy and sustainability, 7(44), 25503-25510. https://doi.org/10.1039/c9ta08378b

• Journal Article Type: Article
• Acceptance Date: Oct 25, 2019
• Online Publication Date: Oct 25, 2019
• Publication Date: Nov 28, 2019
• Deposit Date: Nov 5, 2019
• Publicly Available Date: Oct 25, 2020
• Journal: Journal of Materials Chemistry A: materials for energy and sustainability
• Print ISSN: 2050-7488
• Electronic ISSN: 2050-7496
• Publisher: Royal Society of Chemistry
• Peer Reviewed: Peer Reviewed
• Volume: 7
• Issue: 44
• Pages: 25503-25510
• DOI: https://doi.org/10.1039/c9ta08378b