Investigation of the Relationship between the Structure and Conductivity of the Novel Oxide Ionic Conductor Ba3MoNbO8.5

Sacha Fop, Eve J. Wildman, John T. S. Irvine, Paul A. Connor, Jan M. S. Skakle, Clemens Ritter, Abbie C. McLaughlin

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Abstract

A variable temperature neutron diffraction study of the novel oxide ion conductor Ba3MoNbO8.5 has been performed between 25 and 600 °C. Nonmonotonic behavior of the cell parameters, bond lengths, and angles are observed indicating a structural rearrangement above 300 °C. The oxygen/vacancy distribution changes as the temperature increases so that the ratio of (Mo/Nb)O4 tetrahedra to (Mo/Nb)O6 octahedra increases upon heating above 300 °C. A strong correlation between the oxide ionic conductivity and the number of (Mo/Nb)O4 tetrahedra within the average structure of Ba3MoNbO8.5 is observed. The increase in the number of (Mo/Nb)O4 tetrahedra upon heating from 300–600 °C most likely offers more low energy transition paths for transport of the O2– ions enhancing the conductivity. The unusual structural rearrangement also results in relaxation of Mo(1)/Nb(1) and Ba(2) away from the mobile oxygen, increasing the ionic conductivity. The second order Jahn–Teller effect most likely further enhances the distortion of the MO4/MO6 polyhedra as distortions created by both electronic and structural effects are mutually supportive.
Original languageEnglish
Pages (from-to)4146-4152
Number of pages7
JournalChemistry of Materials
Volume29
Issue number9
Early online date20 Apr 2017
DOIs
Publication statusPublished - 2017

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Ionic conductivity
Oxides
Ions
Heating
Bond length
Oxygen vacancies
Neutron diffraction
Cells
Oxygen
Temperature

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Investigation of the Relationship between the Structure and Conductivity of the Novel Oxide Ionic Conductor Ba3MoNbO8.5. / Fop, Sacha; Wildman, Eve J.; Irvine, John T. S.; Connor, Paul A.; Skakle, Jan M. S.; Ritter, Clemens ; McLaughlin, Abbie C.

In: Chemistry of Materials, Vol. 29, No. 9, 2017, p. 4146-4152.

Research output: Contribution to journalArticle

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title = "Investigation of the Relationship between the Structure and Conductivity of the Novel Oxide Ionic Conductor Ba3MoNbO8.5",
abstract = "A variable temperature neutron diffraction study of the novel oxide ion conductor Ba3MoNbO8.5 has been performed between 25 and 600 °C. Nonmonotonic behavior of the cell parameters, bond lengths, and angles are observed indicating a structural rearrangement above 300 °C. The oxygen/vacancy distribution changes as the temperature increases so that the ratio of (Mo/Nb)O4 tetrahedra to (Mo/Nb)O6 octahedra increases upon heating above 300 °C. A strong correlation between the oxide ionic conductivity and the number of (Mo/Nb)O4 tetrahedra within the average structure of Ba3MoNbO8.5 is observed. The increase in the number of (Mo/Nb)O4 tetrahedra upon heating from 300–600 °C most likely offers more low energy transition paths for transport of the O2– ions enhancing the conductivity. The unusual structural rearrangement also results in relaxation of Mo(1)/Nb(1) and Ba(2) away from the mobile oxygen, increasing the ionic conductivity. The second order Jahn–Teller effect most likely further enhances the distortion of the MO4/MO6 polyhedra as distortions created by both electronic and structural effects are mutually supportive.",
author = "Sacha Fop and Wildman, {Eve J.} and Irvine, {John T. S.} and Connor, {Paul A.} and Skakle, {Jan M. S.} and Clemens Ritter and McLaughlin, {Abbie C.}",
note = "This research was supported by the Northern Research Partnership and the University of Aberdeen. We also acknowledge STFC-GB for provision of beamtime at the ILL.",
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T1 - Investigation of the Relationship between the Structure and Conductivity of the Novel Oxide Ionic Conductor Ba3MoNbO8.5

AU - Fop, Sacha

AU - Wildman, Eve J.

AU - Irvine, John T. S.

AU - Connor, Paul A.

AU - Skakle, Jan M. S.

AU - Ritter, Clemens

AU - McLaughlin, Abbie C.

N1 - This research was supported by the Northern Research Partnership and the University of Aberdeen. We also acknowledge STFC-GB for provision of beamtime at the ILL.

PY - 2017

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N2 - A variable temperature neutron diffraction study of the novel oxide ion conductor Ba3MoNbO8.5 has been performed between 25 and 600 °C. Nonmonotonic behavior of the cell parameters, bond lengths, and angles are observed indicating a structural rearrangement above 300 °C. The oxygen/vacancy distribution changes as the temperature increases so that the ratio of (Mo/Nb)O4 tetrahedra to (Mo/Nb)O6 octahedra increases upon heating above 300 °C. A strong correlation between the oxide ionic conductivity and the number of (Mo/Nb)O4 tetrahedra within the average structure of Ba3MoNbO8.5 is observed. The increase in the number of (Mo/Nb)O4 tetrahedra upon heating from 300–600 °C most likely offers more low energy transition paths for transport of the O2– ions enhancing the conductivity. The unusual structural rearrangement also results in relaxation of Mo(1)/Nb(1) and Ba(2) away from the mobile oxygen, increasing the ionic conductivity. The second order Jahn–Teller effect most likely further enhances the distortion of the MO4/MO6 polyhedra as distortions created by both electronic and structural effects are mutually supportive.

AB - A variable temperature neutron diffraction study of the novel oxide ion conductor Ba3MoNbO8.5 has been performed between 25 and 600 °C. Nonmonotonic behavior of the cell parameters, bond lengths, and angles are observed indicating a structural rearrangement above 300 °C. The oxygen/vacancy distribution changes as the temperature increases so that the ratio of (Mo/Nb)O4 tetrahedra to (Mo/Nb)O6 octahedra increases upon heating above 300 °C. A strong correlation between the oxide ionic conductivity and the number of (Mo/Nb)O4 tetrahedra within the average structure of Ba3MoNbO8.5 is observed. The increase in the number of (Mo/Nb)O4 tetrahedra upon heating from 300–600 °C most likely offers more low energy transition paths for transport of the O2– ions enhancing the conductivity. The unusual structural rearrangement also results in relaxation of Mo(1)/Nb(1) and Ba(2) away from the mobile oxygen, increasing the ionic conductivity. The second order Jahn–Teller effect most likely further enhances the distortion of the MO4/MO6 polyhedra as distortions created by both electronic and structural effects are mutually supportive.

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