Order-disorder transition in the complex lithium spinel Li{sub 2}CoTi{sub 3}O{sub 8}

Journal Article · Fri Jun 15 00:00:00 EDT 2007 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2007.04.015· OSTI ID:21015852

Reeves, Nik ^[1]; Pasero, Denis ^[1]; West, Anthony R ^[1]

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1. Department of Engineering Materials, University of Sheffield, Mappin Street, Sheffield, S1 3JD (United Kingdom)

Li{sub 2}CoTi{sub 3}O{sub 8} has an ordered Li{sub 2}BB'{sub 3}O{sub 8} spinel structure, space group P4{sub 3}32, at room temperature with 3:1 ordering of Ti and Li on the octahedral sites, and Li, Co disordered over the tetrahedral site. Rietveld refinement of variable temperature neutron powder diffraction data has shown an order-disorder phase transition in Li{sub 2}CoTi{sub 3}O{sub 8} which commences at {approx}500 deg. C with Li and Co mixing on the tetrahedral and 4-fold octahedral sites and is complete at a first order structural discontinuity at {approx}915 deg. C. The fraction of Ti on the 12-fold octahedral site exhibits a small decrease with increasing temperature, which may suggest that the disordering involves all three cations. Above 930 deg. C, the structure, space group Fd3-barm, has Li, Co and Ti sharing a single-octahedral site and Li, Co sharing a tetrahedral site, although Co still exhibits a preference for tetrahedral coordination. A labelling scheme for ordered and partially ordered 3:1 spinels is devised which focuses on the occupancy of the Li,B cations. - Graphical abstract: Rietveld refinement of variable temperature neutron powder diffraction data shows an order-disorder phase transition in Li{sub 2}CoTi{sub 3}O{sub 8} commencing at {approx}500 deg. C with Li,Co mixing on tetrahedral and octahedral sites. This becomes complete at a first-order structural discontinuity at {approx}915 deg. C. Above 930 deg. C, the structure, space group Fd3-barm, has Li, Co and Ti sharing a single-octahedral site and Li, Co sharing a tetrahedral site.

• OSTI ID: 21015852
• Journal Information: Journal of Solid State Chemistry, Vol. 180, Issue 6; Other Information: DOI: 10.1016/j.jssc.2007.04.015; PII: S0022-4596(07)00168-5; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CATIONS
COBALT COMPOUNDS
CUBIC LATTICES
LITHIUM COMPOUNDS
NEUTRON DIFFRACTION
NEUTRON TEMPERATURE
ORDER-DISORDER TRANSFORMATIONS
OXIDES
SPACE GROUPS
SPINELS
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 1000-4000 K
TITANIUM COMPOUNDS