New ramsdellites LiTi{sub 2-y}V{sub y}O{sub 4} (0<=y<=1): Synthesis, structure, magnetic properties and electrochemical performances as electrode materials for lithium batteries
- Departamento de Quimica, Facultad de Farmacia, Universidad San Pablo CEU, Ctra. Boadilla del Monte km. 5300, 28668 Boadilla del Monte, Madrid (Spain)
The new ramsdellite series LiTi{sub 2-y}V{sub y}O{sub 4} (0<=y<=1) has been prepared by conventional solid state chemistry techniques and was characterized by X-ray powder diffraction and electron diffraction. To our knowledge, this is the first report on ramsdellites containing vanadium. The magnetic behaviour of these ramsdellites is strongly influenced by its vanadium content. In this sense, LiTi{sub 2}O{sub 4} (y=0) exhibits metallic-like temperature independent paramagnetism, but d electrons tend to localize with increasing V content. LiTiVO{sub 4}, though also paramagnetic, follows then the Curie-Weiss law. The crossover from delocalized to localized electrons is observed between compositions y=0.6 and 0.8. For y>=0.8 the magnetic results evidence an isovalent substitution mechanism of trivalent Ti by V. The electrochemical lithium intercalation and deintercalation chemistry of LiTi{sub 2-y}V{sub y}O{sub 4} is grouped into two different operating voltage regions. Reversible lithium deintercalation of vanadium-substituted ramsdellite titanates LiTi{sub 2-y}V{sub y}O{sub 4} in the high voltage range 2-3 V vs. Li occurs in two main steps, one at about 2 V and the other at about 3 V. The 3 V process capacity increases with the vanadium content, while the 2 V capacity decreases at the same time. The vanadium to titanium substitution rate in LiTi{sub 2}O{sub 4} was found to be beneficial to the specific energy in as much as a 50% increase (1 V) of the working voltage is observed. On the other hand, reversible lithium intercalation in vanadium-substituted ramsdellite titanates LiTi{sub 2-y}V{sub y}O{sub 4} in the low voltage range 1-2 V vs. Li occurs in one main single step, in which the capacity is not affected by the vanadium content, although vanadium-doping produces an improved capacity retention with an excellent cycling behaviour observed for y<=0.6. - Graphical abstract: Ti-based ramsdellite compounds can make up cathode and anode materials for lithium batteries by introducing vanadium. Lithium deinsertion experiments on LiTi{sub 2-y}V{sub y}O{sub 4} materials develop a high operating voltage (3 V) useful as the cathode, while lithium insertion experiments yield a low operating voltage, 1.5 V, useful as the anode. Vanadium-rich compounds show specific theoretical capacity values in the high voltage range that are even comparable to those reported for LiFePO{sub 4} which is presently one of the preferred cathode materials for lithium batteries.
- OSTI ID:
- 21372443
- Journal Information:
- Journal of Solid State Chemistry, Vol. 183, Issue 1; Other Information: DOI: 10.1016/j.jssc.2009.10.009; PII: S0022-4596(09)00491-5; Copyright (c) 2009 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ANODES
CATHODES
CURIE-WEISS LAW
ELECTRIC BATTERIES
ELECTROCHEMISTRY
ELECTRON DIFFRACTION
LITHIUM
LITHIUM COMPOUNDS
MAGNETIC PROPERTIES
PARAMAGNETISM
SYNTHESIS
TITANATES
VANADIUM COMPOUNDS
X-RAY DIFFRACTION
ALKALI METAL COMPOUNDS
ALKALI METALS
CHEMISTRY
COHERENT SCATTERING
DIFFRACTION
ELECTROCHEMICAL CELLS
ELECTRODES
ELEMENTS
ENERGY STORAGE SYSTEMS
ENERGY SYSTEMS
MAGNETISM
METALS
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SCATTERING
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS