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Dynamic Lone Pairs and Fluoride-Ion Disorder in Cubic-BaSnF4.
Mercadier, Briséïs; Coles, Samuel W; Duttine, Mathieu; Legein, Christophe; Body, Monique; Borkiewicz, Olaf J; Lebedev, Oleg; Morgan, Benjamin J; Masquelier, Christian; Dambournet, Damien.
Afiliación
  • Mercadier B; Réseau sur le Stockage Electrochimique de l'Energie, RS2E, FR CNRS 3459, 80039 Amiens Cedex, France.
  • Coles SW; Sorbonne Université, CNRS, Physicochimie des Electrolytes et Nanosystèmes Interfaciaux, UMR CNRS 8234, 75005 Paris, France.
  • Duttine M; Laboratoire de Réactivité et de Chimie du Solides, UMR CNRS 7314, 80039 Amiens Cedex, France.
  • Legein C; Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom.
  • Body M; Quad One, Harwell Science and Innovation Campus, The Faraday Institution, Didcot OX11 0RA, United Kingdom.
  • Borkiewicz OJ; Institut de Chimie de la Matière Condensée de Bordeaux, UMR CNRS 5026, 33608 Pessac, France.
  • Lebedev O; Institut des Molécules et Matériaux du Mans, UMR CNRS 6283, Le Mans Université, 72085 Le Mans Cedex 9, France.
  • Morgan BJ; Institut des Molécules et Matériaux du Mans, UMR CNRS 6283, Le Mans Université, 72085 Le Mans Cedex 9, France.
  • Masquelier C; X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, United States.
  • Dambournet D; Laboratoire de Cristallographie et Sciences des Matériaux, CRISMAT, 14000 Caen, France.
J Am Chem Soc ; 145(43): 23739-23754, 2023 Nov 01.
Article en En | MEDLINE | ID: mdl-37844155
Introducing compositional or structural disorder within crystalline solid electrolytes is a common strategy for increasing their ionic conductivity. (M,Sn)F2 fluorites have previously been proposed to exhibit two forms of disorder within their cationic host frameworks: occupational disorder from randomly distributed M and Sn cations and orientational disorder from Sn(II) stereoactive lone pairs. Here, we characterize the structure and fluoride-ion dynamics of cubic BaSnF4, using a combination of experimental and computational techniques. Rietveld refinement of the X-ray diffraction (XRD) data confirms an average fluorite structure with {Ba,Sn} cation disorder, and the 119Sn Mössbauer spectrum demonstrates the presence of stereoactive Sn(II) lone pairs. X-ray total-scattering PDF analysis and ab initio molecular dynamics simulations reveal a complex local structure with a high degree of intrinsic fluoride-ion disorder, where 1/3 of fluoride ions occupy octahedral "interstitial" sites: this fluoride-ion disorder is a consequence of repulsion between Sn lone pairs and fluoride ions that destabilizes Sn-coordinated tetrahedral fluoride-ion sites. Variable-temperature 19F NMR experiments and analysis of our molecular dynamics simulations reveal highly inhomogeneous fluoride-ion dynamics, with fluoride ions in Sn-rich local environments significantly more mobile than those in Ba-rich environments. Our simulations also reveal dynamical reorientation of the Sn lone pairs that is biased by the local cation configuration and coupled to the local fluoride-ion dynamics. We end by discussing the effect of host-framework disorder on long-range diffusion pathways in cubic BaSnF4.
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Idioma: En Revista: J Am Chem Soc Año: 2023 Tipo del documento: Article País de afiliación: Francia Pais de publicación: Estados Unidos
Texto completo
Añadir a Mi BVS
Imprimir
XML
PubMed Links
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Idioma: En Revista: J Am Chem Soc Año: 2023 Tipo del documento: Article País de afiliación: Francia Pais de publicación: Estados Unidos