High-resolution time-of-flight neutron powder diffraction data (ISIS facility, Rutherford Appleton Laboratory, U. K.) were collected on sample I, prepared by slow cooling from 1300 °C, of the Li<sub>0.3</sub>La <sub>0.567</sub>TiO<sub>3</sub> (LLTO) lithium ion conductor, and on sample II quenched in liquid N<sub>2</sub>. Patterns were obtained at room temperature (RT), 400 and 700 °C on sample I, and at 550 °C on sample II, studied at RT in previous work. The structure was resolved and Rietveld refined in the tetragonal P4/nbm space group with √2a<sub>p</sub> × √2a <sub>p</sub> × 2a<sub>p</sub> unit-cell [a = 5.48162(1), c = 7.74646(1) Å at RT, Z = 4; a<sub>p</sub> is the cell edge of cubic perovskite] in all cases except 700 °C, where a P4/mmm (a<sub>p</sub> × a<sub>p</sub> × 2a<sub>p</sub>) structure was determined and refined [a = 3.89827(2), c = 7.8002(1) Å, Z = 2]. In both space groups lanthanum ordering over two La1 and La2 sites is present, but only in P4/nbm can an additional anti-phase octahedral tilting of type a<sup>0</sup>a<sup>0</sup>c<sup>-</sup> be observed, similar to what occurs in the I4/mcm RT metastable phase of the quenched sample. The two distortions are associated to hkl superlattice reflections with h + k even, l odd, and h + k odd, l odd, respectively. Lithium atoms were located in highly disordered sites within the less populated La1 hollows, with short Li-Li′ distances accounting for the high ionic mobility. Possible ordering schemes indicate a mainly (001) two-dimensional mechanism of ion hopping among Li sites. © The Royal Society of Chemistry 2007.

Catti, M., Sommariva, M., Ibberson, R. (2007). Tetragonal superstructure and thermal history of Li0.3La0.567TiO3 (LLTO) solid electrolyte by neutron diffraction. JOURNAL OF MATERIALS CHEMISTRY, 17(13), 1300-1307 [10.1039/B614345H].

Tetragonal superstructure and thermal history of Li0.3La0.567TiO3 (LLTO) solid electrolyte by neutron diffraction

CATTI, MICHELE;
2007

Abstract

High-resolution time-of-flight neutron powder diffraction data (ISIS facility, Rutherford Appleton Laboratory, U. K.) were collected on sample I, prepared by slow cooling from 1300 °C, of the Li0.3La 0.567TiO3 (LLTO) lithium ion conductor, and on sample II quenched in liquid N2. Patterns were obtained at room temperature (RT), 400 and 700 °C on sample I, and at 550 °C on sample II, studied at RT in previous work. The structure was resolved and Rietveld refined in the tetragonal P4/nbm space group with √2ap × √2a p × 2ap unit-cell [a = 5.48162(1), c = 7.74646(1) Å at RT, Z = 4; ap is the cell edge of cubic perovskite] in all cases except 700 °C, where a P4/mmm (ap × ap × 2ap) structure was determined and refined [a = 3.89827(2), c = 7.8002(1) Å, Z = 2]. In both space groups lanthanum ordering over two La1 and La2 sites is present, but only in P4/nbm can an additional anti-phase octahedral tilting of type a0a0c- be observed, similar to what occurs in the I4/mcm RT metastable phase of the quenched sample. The two distortions are associated to hkl superlattice reflections with h + k even, l odd, and h + k odd, l odd, respectively. Lithium atoms were located in highly disordered sites within the less populated La1 hollows, with short Li-Li′ distances accounting for the high ionic mobility. Possible ordering schemes indicate a mainly (001) two-dimensional mechanism of ion hopping among Li sites. © The Royal Society of Chemistry 2007.
Articolo in rivista - Articolo scientifico
neutron diffraction; Li+ ion conductors; LLTO phases
English
2007
17
13
1300
1307
none
Catti, M., Sommariva, M., Ibberson, R. (2007). Tetragonal superstructure and thermal history of Li0.3La0.567TiO3 (LLTO) solid electrolyte by neutron diffraction. JOURNAL OF MATERIALS CHEMISTRY, 17(13), 1300-1307 [10.1039/B614345H].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/13302
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