NMR evidence of LiF coating rather than fluorine substitution in Li(Ni{sub 0.425}Mn{sub 0.425}Co{sub 0.15})O{sub 2}

Journal Article · Mon Dec 15 00:00:00 EST 2008 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2008.09.002· OSTI ID:21212137

Menetrier, M; Bains, J ^[1]; Flambard, A; Bekaert, E ^[1]; Jordy, C; Biensan, Ph ^[2]; Delmas, C ^[1]

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1. ICMCB, CNRS, Universite Bordeaux 1, Site ENSCPB, 87 avenue Schweitzer, 33608 PESSAC cedex (France)
2. SAFT, Direction de la Recherche, 111-113 Bld Alfred Daney, 33074 Bordeaux (France)

A series of 'Li{sub 1+z/2}(Ni{sub 0.425}Mn{sub 0.425}Co{sub 0.15}){sub 1-z/2}O{sub 2-z}F{sub z}' materials was prepared by a coprecipitation route and their structure was characterized using X-ray diffraction (XRD), as well as {sup 7}Li and {sup 19}F Magic Angle Spinning (MAS) NMR spectroscopy. Two hypotheses were considered: (i) formation of layered oxyfluoride materials and (ii) formation of a mixture between the layered material and LiF. Structural parameters were refined by the Rietveld method, using XRD diffraction data. The refinement results did not allow us to choose between these two hypotheses: no significant change in crystallinity and structural parameters was observed irrespective of the fluorine ratio. {sup 7}Li and {sup 19}F MAS NMR analyses showed signals with isotropic positions characteristic of LiF, but envelopes characteristic of very strong dipolar interactions with the electron spins of the material, demonstrating that LiF was not incorporated into the layered oxide structure but was instead present as a coating. - Graphical abstract: {sup 7}Li and {sup 19}F MAS NMR show signals with isotropic positions characteristic of LiF, but with spinning sidebands envelopes characteristic of very strong dipolar interactions with the electron spins of the layered oxide, demonstrating that F is not a part of the material but is present as an LiF coating.

• OSTI ID: 21212137
• Journal Information: Journal of Solid State Chemistry, Vol. 181, Issue 12; Other Information: DOI: 10.1016/j.jssc.2008.09.002; PII: S0022-4596(08)00475-1; Copyright (c) 2008 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
COBALT COMPOUNDS
COPRECIPITATION
ELECTRIC BATTERIES
FLUORINE
FLUORINE 19
HYPOTHESIS
INTERACTIONS
LITHIUM 7
LITHIUM COMPOUNDS
LITHIUM FLUORIDES
LITHIUM IONS
MANGANESE COMPOUNDS
NICKEL COMPOUNDS
NUCLEAR MAGNETIC RESONANCE
OXIDES
OXYFLUORIDES
SPECTROSCOPY
X-RAY DIFFRACTION