Nuclear and Magnetic Structure of Layered LiFe1−xCoxO2 (0≤x≤1) Determined by High-Resolution Neutron Diffraction

Douakha, N.; Holzapfel, Michael; Chappel, Eric; Chouteau, G.; Croguennec, Laurence; Ott, A.; Ouladdiaf, B.

doi:10.1006/jssc.2001.9413

Cited by 33 publications

(26 citation statements)

References 24 publications

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“…By adopting the m-LiFeO 2 -type structure, a superstructure of the rock-salt structure type [12], ε-SrSiN 2 finally follows the trend we have already discovered for BeSiN 2 , MgSiN 2 and CaSiN 2 [1].…”

Section: Discussionmentioning

confidence: 53%

High-pressure phases and transitions of the layered alkaline earth nitridosilicates SrSiN₂and BaSiN₂

Römer

Kroll

Schnick

2009

J. Phys.: Condens. Matter

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We investigate the high-pressure phase diagram of SrSiN 2 and BaSiN 2 with density-functional calculation. Searching a manifold of possible candidate structures, we propose new structural modifications of SrSiN 2 and BaSiN 2 attainable in high-pressure experiments. The monoclinic ground state of SrSiN 2 transforms at 3 GPa into an orthorhombic BaSiN 2 type. At 14 GPa a CaSiN 2 -type structure becomes the most stable configuration of SrSiN 2 . A hitherto unknown Pbcm modification is adopted at 85 GPa and, finally, at 131 GPa a LiFeO 2 -type structure. The higher homologue BaSiN 2 transforms to a CaSiN 2 type at 41 GPa and further to a Pbcm modification at 105 GPa. Both systems follow the pressure-coordination rule: the coordination environment of Si increases from tetrahedral through trigonal bipyramidal to octahedral. Some high-pressure phases are related in structure through simple group-subgroup mechanisms, indicating displacive phase transformations with low activation barriers.

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Section: Discussionmentioning

confidence: 53%

High-pressure phases and transitions of the layered alkaline earth nitridosilicates SrSiN₂and BaSiN₂

Römer

Kroll

Schnick

2009

J. Phys.: Condens. Matter

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“…Double (001) Li-O layers alternate with similar Fe-O layers, corresponding to (011) planes of the rocksalt reference structure. In the 'layered' R 3m polymorph 24,25 (isomorphous to LiCoO 2 ), also derived from the rocksalt structure, Li-Fe (Li-Co) ordering occurs according to the (111) close-packed FCC planes. Diffusion of Li + ions in Pmmn-LiFeO 2 should be evidently confined within the lithium double layers; ion hopping may occur between centres of edge-sharing adjacent LiO 6 octahedra, connected by the shortest Li-Li distance of about 3 A ˚.…”

Section: Resultsmentioning

confidence: 99%

Lithium diffusion pathways and vacancy formation in the Pmmn-Li1−xFeO2 electrode material

Catti

Montero‐Campillo

2011

Phys. Chem. Chem. Phys.

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Models for Li(+) ion mobility were developed and investigated in the 'corrugated layer' orthorhombic phase of Li(1-x)FeO(2), an attractive possible electrode material for reversible lithium ion batteries. The ground-state crystal energy was computed by first-principles DFT (Density-Functional-Theory) methods, based on the use of the hybrid B3LYP functional with localized Gaussian-type basis sets. Appropriate supercells were devised as needed, with full least-energy structure optimization. In the defect-free case (x = 0), ion diffusion was found to take place cooperatively inside a fraction of active lithium layers separated by inert ones, so as to reduce lattice strain; intermediate bottleneck states of Li are either in tetrahedral (energy barrier ΔE(a) = 0.410 eV) or linear (ΔE(a) = 0.468 eV) coordination. For the Li(0.75)FeO(2) deintercalated material a number of low energy vacancy configurations were considered, investigating also the vacancy influence on electron density of states and atomic charge distribution. The most favourable ion transport mechanisms (ΔE(a) = 0.292 and 0.304 eV) imply a linear Li bottleneck state, with all lithium layers active and a quite small lattice strain. Accordingly, in the defective material the predicted ionic conductivity at room temperature rises from 10(-5)-10(-6) (LiFeO(2)) to 4 × 10(-4) ohm(-1) cm(-1) (Li(0.75)FeO(2)).

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“…These values correspond well with the experimentally determined metal-metal distance in layered LiAlO 2 and LiFeO 2 : 2.799 and 2.955 A ˚, respectively. 38, 52 The extension of the Fe 3+ Al 3+ distance up to 2.85 A ˚causes a slight decrease of D, followed by a strong increase for r > 2.85 A ˚. This value is higher than that provided by the host matrix.…”

Section: Computation Of Zfs Parameters For Fe 3+ and Mn 4+mentioning

confidence: 96%

Local structure of Mn4+ and Fe3+ spin probes in layered LiAlO2 oxide by modelling of zero-field splitting parameters

et al. 2011

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The zero-field splitting parameters (ZFS) of Mn(4+) and Fe(3+) ions in LiAlO(2) with a layered structure are analyzed experimentally and theoretically by using high-frequency electron paramagnetic resonance spectroscopy, Neuman superposition model (NSM), DFT and multiconfigurational calculations. The interpretation of ZFS is based on the comparison of the experimentally determined values with the calculated ones. This approach allows assessing the performance of different methods for computation of ZFS of Fe(3+) and Mn(4+) in layered oxide matrices. DFT and multiconfigurational calculations are used to analyze the effect of oxygen, aluminium, and lithium neighbours on ZFS of Fe(3+) and Mn(4+). These calculations are based on a cluster comprising Fe(3+) or Mn(4+) ions in a trigonally compressed octahedron with 6 metal ions (Al(3+) or Co(3+)) as first metal neighbours and 6 O(2-) and 2 Li(+) (above and below the layer) as second neighbours. A satisfactory agreement with the experimental data is achieved when the local structure of Mn(4+) and Fe(3+) deviates from the trigonal host-site geometry. The local structure of Fe(3+) comprises an axial distortion, while trigonal environment with reduced extent of distortion appears around Mn(4+).

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Nuclear and Magnetic Structure of Layered LiFe1−xCoxO2 (0≤x≤1) Determined by High-Resolution Neutron Diffraction

Cited by 33 publications

References 24 publications

High-pressure phases and transitions of the layered alkaline earth nitridosilicates SrSiN₂and BaSiN₂

High-pressure phases and transitions of the layered alkaline earth nitridosilicates SrSiN₂and BaSiN₂

Lithium diffusion pathways and vacancy formation in the Pmmn-Li1−xFeO2 electrode material

Local structure of Mn4+ and Fe3+ spin probes in layered LiAlO2 oxide by modelling of zero-field splitting parameters

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Nuclear and Magnetic Structure of Layered LiFe1−xCoxO2 (0≤x≤1) Determined by High-Resolution Neutron Diffraction

Cited by 33 publications

References 24 publications

High-pressure phases and transitions of the layered alkaline earth nitridosilicates SrSiN2and BaSiN2

High-pressure phases and transitions of the layered alkaline earth nitridosilicates SrSiN2and BaSiN2

Lithium diffusion pathways and vacancy formation in the Pmmn-Li1−xFeO2 electrode material

Local structure of Mn4+ and Fe3+ spin probes in layered LiAlO2 oxide by modelling of zero-field splitting parameters

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High-pressure phases and transitions of the layered alkaline earth nitridosilicates SrSiN₂and BaSiN₂

High-pressure phases and transitions of the layered alkaline earth nitridosilicates SrSiN₂and BaSiN₂