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Polymorphism and Oxide Ion Migration Pathways in Fluorite-Type Bismuth Vanadate, Bi46V8O89

DOI: 10.1021/cm3008107 DOI Help

Authors: Xiaojun Kuang (Durham University, U.K.) , Julia L. Payne (Durham University, U.K.) , James D. Farrell (Durham University, U.K.) , Mark R. Johnson (Institute Laue Langevin, Grenoble, France) , Ivana Radosavljevic Evans (Durham University, U.K.)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Chemistry Of Materials , VOL 24 (11) , PAGES 2162 - 2167

State: Published (Approved)
Published: June 2012

Abstract: We report the synthesis, structural characterization, and ionic conductivity measurements for a new polymorph of bismuth vanadate Bi46V8O89, and an ab initio molecular dynamics study of this oxide ion conductor. Structure determination was carried out using synchrotron powder X-ray and neutron diffraction data; it was found that β-Bi46V8O89 crystallizes in space group C2/m and that the key differences between this and the previously reported α-form are the distribution of Bi and V cations and the arrangement of the VO4 coordination polyhedra in structure. β-Bi46V8O89 exhibits good oxide ion conductivity, with σ = 0.01–0.1 S/cm between 600 and 850 °C, which is about an order of magnitude higher than yttria stabilized zirconia. The ab initio molecular dynamics simulations suggest that the ion migration pathways include vacancy diffusion through the Bi–O sublattice, as well as the O2– exchanges between the Bi–O and the V–O sublattices, facilitated by the variability of the vanadium coordination environment and the rotational freedom of the VOx coordination polyhedra.

Journal Keywords: Oxide Ion Conductors; Bismuth Vanadates; X-Ray And Neutron Diffraction; Aimd Simulations

Subject Areas: Chemistry

Instruments: I11-High Resolution Powder Diffraction

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