Cation distribution and phase transformations in LiMn2-yTiyO4 (0.2 ≤ y ≤ 1.5) solid solutions
Series of lithium manganese titanium spinel-like oxides LiMn2-yTiyO4 (0.2y1.5) were synthesized by solid state reaction carried out at 1100 deg C, followed by slow cooling to a particular temperature, depending on the titanium content y, and then air-quenched to room temperature. The procedure has p...
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Published in | Solid state sciences Vol. 7; no. 3; pp. 277 - 286 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
Paris
Elsevier
01.03.2005
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Subjects | |
Online Access | Get full text |
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Summary: | Series of lithium manganese titanium spinel-like oxides LiMn2-yTiyO4 (0.2y1.5) were synthesized by solid state reaction carried out at 1100 deg C, followed by slow cooling to a particular temperature, depending on the titanium content y, and then air-quenched to room temperature. The procedure has permitted to obtain single-phase products. The samples have been characterized by X-ray powder diffraction (XRD), thermal analysis (TG) and electron paramagnetic resonance (EPR) spectroscopy. Compounds whose composition falls within the interval 0.2y1.0 crystallize in the space group Fd3m, whereas those having y > 1.0 crystallize in the space group P4332. Analysis of the structural parameters refined from XRD data revealed that the tetrahedral sites are occupied by Li+ and Mn2+. The end member , which was synthesized in argon atmosphere, is reported for the first time. It crystallizes in the space group P4332, , with all Mn2+ ions being situated at the tetrahedral sites. Its EPR spectrum consists of a Lorentzian-shaped line, centered at g=2.004 with a peak-to-peak width of 25.7 mT. This line has been assigned to Mn2+ ions. Rietveld structure refinement results show that asyincreases from 0 to 1.5 the occupancy factor of Mn2+ in the tetrahedral sites increases from 0 to 0.5, while the occupancy factors of Mn3+ and Mn4+ in the mixed (Mn3+, Mn4+, Ti4+) octahedral sites decrease from 1 to 0. |
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Bibliography: | ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 |
ISSN: | 1293-2558 1873-3085 |
DOI: | 10.1016/j.solidstatesciences.2004.10.041 |