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Titel: Mechanochemical Induced Structure Transformations in Lithium Titanates: A Detailed PXRD and 6Li MAS NMR Study
VerfasserIn: Becker, Dennis
Haberkorn, Robert
Kickelbick, Guido
Sprache: Englisch
Titel: Inorganics
Bandnummer: 6
Heft: 4
Verlag/Plattform: MDPI
Erscheinungsjahr: 2018
Freie Schlagwörter: lithium titanium oxide
mechanochemistry
high energy ball milling
X-ray diffraction
Rietveld refinement
6Li SPE MAS NMR
impedance spectroscopy
DDC-Sachgruppe: 540 Chemie
Dokumenttyp: Journalartikel / Zeitschriftenartikel
Abstract: Lithium titanates are used in various applications, such as anode materials for lithium intercalation (Li4Ti5O12) or breeding materials in fusion reactors (Li2TiO3). Here, we report the formation of nano-crystalline lithium titanates by a mechanochemical approach and present a deeper insight into their structural characteristics by X-ray diffraction (XRD) and solid-state NMR spectroscopy. The compounds were synthesized in a high-energy planetary ball mill with varying milling parameters and different grinding tools. NaCl type Li2TiO3 (α-Li2TiO3) was formed by dry milling of lithium hydroxide with titania (rutile or anatase) and by a milling induced structure transformation of monoclinic β-Li2TiO3 or spinel type Li4Ti5O12. Heating of mechanochemical prepared α-Li2TiO3 induces a phase transformation to the monoclinic phase similar to hydrothermal reaction products, but a higher thermal stability was observed for the mechanochemical formed product. Microstructure and crystallographic structure were characterized by XRD via Rietveld analysis. Detailed phase analysis shows the formation of the cubic phase from the various educts. A set of two lattice parameters for α-Li2TiO3 was refined, depending on the presence of OH− during the milling process. An average crystallite size of less than 15 nm was observed for the mechanochemical generated products. The local Li environment detected by 6Li NMR revealed Li defects in the form of tetrahedral instead of octahedral site occupation. Subsequent adjustment of the structural model for Rietveld refinement leads to better fits, supporting this interpretation
DOI der Erstveröffentlichung: 10.3390/inorganics6040117
Link zu diesem Datensatz: urn:nbn:de:bsz:291--ds-275216
hdl:20.500.11880/29496
http://dx.doi.org/10.22028/D291-27521
ISSN: 2304-6740
Datum des Eintrags: 7-Aug-2020
Bezeichnung des in Beziehung stehenden Objekts: Supplementary Materials
In Beziehung stehendes Objekt: https://www.mdpi.com/2304-6740/6/4/117/s1
Fakultät: NT - Naturwissenschaftlich- Technische Fakultät
Fachrichtung: NT - Chemie
Professur: NT - Prof. Dr. Guido Kickelbick
Sammlung:SciDok - Der Wissenschaftsserver der Universität des Saarlandes

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