New Insights into the Crystal and Electronic Structures of Li_1+xV_1-xO₂ from Solid State NMR, Pair Distribution Function Analyses, and First Principles Calculations

Journal Article · Mon Oct 29 00:00:00 EDT 2012 · Chemistry of Materials

DOI:https://doi.org/10.1021/cm300662m· OSTI ID:1048564

Pourpoint, Frédérique; Hua, Xiao; Middlemiss, Derek S; Adamson, Paul; Wang, Da; Bruce, Peter G; Grey, Clare P ^[1]

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1. SBU

Pair distribution function (PDF) analyses of synchrotron data obtained for the anode materials Li_1+xV_1-xO₂ (0 ≤ x ≤ 0.1) have been performed to characterize the short to medium range structural ordering. The data show clear evidence for the magnetically-induced distortion of the V sublattice to form trimers, the distortion persisting at even the highest excess Li content considered of x = 0.1. At least three distinct local environments were observed for the stoichiometric material LiVO₂ in ⁶Li nuclear magnetic resonance (NMR) spectroscopy, the environments becoming progressively more disordered as the Li content increases. A two-dimensional Li-Li correlation NMR experiment (POST-C7) was used to identify the resonances corresponding to Li within the same layers. NMR spectra were acquired as a function of the state of charge, a distinct environment for Li in Li₂VO₂ being observed. The results suggest that disorder within the Li layers (in addition to the presence of Li within the V layers as proposed by Armstrong et al. Nat. Mater.2011, 10, 223-229) may aid the insertion of Li into the Li_1+xV_1-xO₂ phase. The previously little-studied Li₂VO₂ phase was also investigated by hybrid density functional theory (DFT) calculations, providing insights into magnetic interactions, spin-lattice coupling, and Li hyperfine parameters.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
• Sponsoring Organization: DOE - BASIC ENERGY SCIENCES
• OSTI ID: 1048564
• Journal Information: Chemistry of Materials, Vol. 24, Issue (15) ; 08, 2012; ISSN 0897-4756
• Publisher: American Chemical Society (ACS)
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ANODES
DISTRIBUTION FUNCTIONS
ELECTRONIC STRUCTURE
FUNCTIONALS
NMR SPECTRA
NUCLEAR MAGNETIC RESONANCE
SPECTROSCOPY
SYNCHROTRONS