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Main Title: Lithium diffusion pathways in metastable ramsdellite-like Li2Ti3O7 from high-temperature neutron diffraction
Author(s): Wiedemann, Dennis
Nakhal, Suliman
Franz, Alexandra
Lerch, Martin
Type: Article
Language Code: en
Abstract: Ramsdellite-like Li2Ti3O7 is an excellent, strongly anisotropic lithium-ion conductor with various proposed applications in energy storage and lithium processing. Diffusion pathways have not yet been thoroughly studied, in spite of their importance for these purposes; even the precise crystal structure of this material is a subject of ongoing discussion. Herein, we use variable-temperature neutron diffraction in the metastability range of ramsdellite-like Li2Ti3O7 to probe the nontrivial lithium-ion distribution. Refinement with anisotropic displacement parameters including anharmonic terms identifies the room-temperature structure as statically disordered snapshot of the dynamic behavior at synthesis temperature. Mapping of scattering-length density, reconstructed using maximum-entropy methods (MEM), shows the signature of partial relaxation and activation of lithium movement with increasing temperature. Scrutinous topological analyses of procrystal voids and Voronoi–Dirichlet partitioning (VDP) reveal lithium diffusion along ribbons in the interstitial channels as the major and diffusion through framework vacancies as the most probable minor mechanism. By rationalizing former empirical results, we provide deeper insight into this paradigmatic example of strongly anisotropic lithium-ion conductors.
Issue Date: Oct-2016
Date Available: 16-Sep-2016
DDC Class: 530 Physik
Subject(s): dilithium trititanate
lithium migration
neutron powder diffraction
Voronoi–Dirichlet partitioning
procrystal void surface
maximum-entropy methods
Sponsor/Funder: DFG, FOR 1277, Mobilität von Lithiumionen in Festkörpern (molife)
Journal Title: Solid state ionics : diffusion and reactions
Publisher: Elsevier
Publisher Place: Amsterdam [u.a.]
Volume: 293
Publisher DOI: 10.1016/j.ssi.2016.06.002
Page Start: 37
Page End: 43
EISSN: 1872-7689
ISSN: 0167-2738
Appears in Collections:FG Anorganische Chemie - Festkörper- und Materialchemie » Publications

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