Rational design of a commensurate (3+3)-D modulated structure within the fast-ion conducting stabilized δ-Bi2O3 series
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Type
ArticleAuthor/s
Wind, JuliaPolt, Julia
Zhang, Zhaoming
Blom, Douglas A
Vogt, Thomas
Withers, Ray L
Ling, Chris D
Abstract
We report the systematic design, preparation, and characterization of the first commensurate member of the oxide-ionic conducting, (3 + 3)-D modulated, Type II phases of doped δ-Bi2O3. The incommensurate Type II modulation vector ε was previously described as continuously variable, ...
See moreWe report the systematic design, preparation, and characterization of the first commensurate member of the oxide-ionic conducting, (3 + 3)-D modulated, Type II phases of doped δ-Bi2O3. The incommensurate Type II modulation vector ε was previously described as continuously variable, but high-resolution synchrotron X-ray powder diffraction data show that close to the composition Bi23CrNb3O45, it “locks in” to ε = 1/3. The space group of the resulting 3 × 3 × 3 fluorite-type supercell was found to be F4̅3m by selected-area electron diffraction, and the structure was solved and Rietveld-refined against neutron powder diffraction data in conjunction with local structural information from X-ray absorption spectroscopy, high-resolution transmission electron microscopy, and ab initio geometry optimization calculations. The result unambiguously validates the crystal-chemical model of the Type II phases as being based on the local ordering of oxygen around transition metals M into tetrahedral clusters of MO6 octahedra and isolated MO4 tetrahedra, separating relatively disordered fluorite-type regions that facilitate the highest oxide-ionic conduction among transition metal-doped δ-Bi2O3 phases.
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See moreWe report the systematic design, preparation, and characterization of the first commensurate member of the oxide-ionic conducting, (3 + 3)-D modulated, Type II phases of doped δ-Bi2O3. The incommensurate Type II modulation vector ε was previously described as continuously variable, but high-resolution synchrotron X-ray powder diffraction data show that close to the composition Bi23CrNb3O45, it “locks in” to ε = 1/3. The space group of the resulting 3 × 3 × 3 fluorite-type supercell was found to be F4̅3m by selected-area electron diffraction, and the structure was solved and Rietveld-refined against neutron powder diffraction data in conjunction with local structural information from X-ray absorption spectroscopy, high-resolution transmission electron microscopy, and ab initio geometry optimization calculations. The result unambiguously validates the crystal-chemical model of the Type II phases as being based on the local ordering of oxygen around transition metals M into tetrahedral clusters of MO6 octahedra and isolated MO4 tetrahedra, separating relatively disordered fluorite-type regions that facilitate the highest oxide-ionic conduction among transition metal-doped δ-Bi2O3 phases.
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Date
2017-01-01Publisher
American Chemical SocietyLicence
This document is the unedited Author’s version of a Submitted Work that was subsequently accepted for publication in Chemistry of Materials, copyright © American Chemical Society after peer review. To access the final edited and published work see http://dx.doi.org/10.1021/acs.chemmater.7b03012Citation
J Wind, J Polt, Z Zhang, DA Blom, T Vogt, RL Withers and CD Ling, Chemistry of Materials 29, 9171–9181 (2017) http://dx.doi.org/10.1021/acs.chemmater.7b03012Share