Theoretical calculation of electronic structure and X-ray absorption near-edge structure of cathode materials for Li ion batteries

Jeon, Young-Ah; Kim, Yang-Soo; Kim, Sungkwan; No, Kwangsoo

doi:10.1016/j.ssi.2006.04.027

Cited by 5 publications

(3 citation statements)

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“…Some DFT calculations have been carried out for the typical layered compound, O3-LiCoO 2 , including XANES simulations. [16][17][18][19][20][21][22][23] In the other paper, we conducted XANES simulations at the Co K-edges in Li 1Àx CoO 2 (À1 # x # 1) lithium ions intercalated/de-intercalated from O3-LiCoO 2 and discussed the relationship between the valence state and XANES spectral position. 24 In the present study, we concentrated on the effect of the local structure around absorbed atoms on XANES spectra.…”

Section: Introductionmentioning

confidence: 99%

Correlation of lithium ion distribution and X-ray absorption near-edge structure in O3- and O2-lithium cobalt oxides from first-principle calculation

et al. 2012

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Section: Introductionmentioning

confidence: 99%

Correlation of lithium ion distribution and X-ray absorption near-edge structure in O3- and O2-lithium cobalt oxides from first-principle calculation

et al. 2012

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“…3,10,13,14 Furthermore, the life cycle of the lowtemperature "polymorph" is poor, which gives evidence for the intrinsic instability of the delithiated structure. 1 High-resolution neutron diffraction indicated a cation distribution that is intermediate between an ideal layered structure and an ideal lithiated spinel structure.…”

Section: Introductionmentioning

confidence: 99%

“…In general, it is considered that LT-Li x CoO 2 has a cubic close-packed oxygen lattice that remains unaffected by lithium extraction, in contrast to the trigonal high-temperature polymorph with a c / a ratio that increases from 4.99 at x = 1 to 5.12 at x = 0.5. ,,, Furthermore, the life cycle of the low-temperature “polymorph” is poor, which gives evidence for the intrinsic instability of the delithiated structure . High-resolution neutron diffraction indicated a cation distribution that is intermediate between an ideal layered structure and an ideal lithiated spinel structure .…”

Section: Introductionmentioning

confidence: 99%

Voltage−Composition Profile and Synchrotron X-ray Structural Analysis of Low and High Temperature Li_xCoO₂ Host Material

et al. 2008

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In the present work, the intercalation of lithium ions in the Li x CoO 2 host material was investigated by means of the discharge curves and voltage-composition profile with the main goal of establishing a close correlation between the voltage-composition patterns and the structure of the Li x CoO 2 prepared at low and high temperatures. As a result, the structures of the Li x CoO 2 prepared at low and high temperatures were investigated by a careful analysis of synchrotron X-ray powder diffraction (including a quantitative Rietveld refinement), which showed the presence of two majority phases for Li x CoO 2 prepared at low temperature, that is, spinel and layered phases. On the basis of the information provided by the quantitative structural analysis, the voltagecomposition profiles were interpreted by considering at least two ionic modes of charges, one in which lithium ions occupy sites in the spinel structure and the other in which lithium ions occupy the sites of the layered structure. It was found that at least two modes (two types of site to charged) of charge were related to the layered structure during ionic charging of the host. Finally, and curiously, it was found that the decreasing of the charge capacity as a function of charge-discharge cycles is mainly related to a type of site located in the layered structure (or sites related to layered phase transition, i.e. order-disorder transition from hexagonal to monoclinic symmetry).

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Theoretical Study on the Correlation between the Nature of Atomic Li Intercalation and Electrochemical Reactivity in TiS₂ and TiO₂

Kim

Jeon

et al. 2009

J. Phys. Chem. A

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The electronic structures of LiTiS(2) and LiTiO(2) (having alpha-NaFeO(2) structure) have been investigated using discrete variational Xalpha molecular orbital methods. The alpha-NaFeO(2) structure is the equilibrium structure for LiCoO(2), which is widely used as a commercial cathode material for lithium secondary batteries. This study especially focused on the charge state of Li ions and the magnitude of covalency around Li ions. When the average voltage of lithium intercalation was calculated using pseudopotential methods, the average intercalation voltage of LiTiO(2) (2.076 V) was higher than that of LiTiS(2) (1.958 V). This can be explained by the differences in Mulliken charge of lithium and the bond overlap population between the intercalated Li ions and anion in LiTiO(2) as well as LiTiS(2). The Mulliken charge, which is the ionicity of Li atom, was approximately 0.12 in LiTiS(2), and the bond overlap population (BOP) indicating the covalency between Ti and S was about 0.339. When compared with the BOP (0.6) of C-H, which is one of the most famous example of covalent bonding, the intercalated Li ions in LiTiS(2) tend to form a quite strong covalent bond with the host material. In contrast, the Mulliken charge of lithium was about 0.79, which means that Li is fully ionized and the BOP, the covalency between Ti and O, was 0.181 in LiTiO(2). Because of the high ionicity of Li and the weak covalency between Ti and the nearest anion, LiTiO(2) has a higher intercalation voltage than LiTiS(2).

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Theoretical calculation of electronic structure and X-ray absorption near-edge structure of cathode materials for Li ion batteries

Cited by 5 publications

References 14 publications

Correlation of lithium ion distribution and X-ray absorption near-edge structure in O3- and O2-lithium cobalt oxides from first-principle calculation

Correlation of lithium ion distribution and X-ray absorption near-edge structure in O3- and O2-lithium cobalt oxides from first-principle calculation

Voltage−Composition Profile and Synchrotron X-ray Structural Analysis of Low and High Temperature Li_xCoO₂ Host Material

Theoretical Study on the Correlation between the Nature of Atomic Li Intercalation and Electrochemical Reactivity in TiS₂ and TiO₂

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Theoretical calculation of electronic structure and X-ray absorption near-edge structure of cathode materials for Li ion batteries

Cited by 5 publications

References 14 publications

Correlation of lithium ion distribution and X-ray absorption near-edge structure in O3- and O2-lithium cobalt oxides from first-principle calculation

Correlation of lithium ion distribution and X-ray absorption near-edge structure in O3- and O2-lithium cobalt oxides from first-principle calculation

Voltage−Composition Profile and Synchrotron X-ray Structural Analysis of Low and High Temperature LixCoO2 Host Material

Theoretical Study on the Correlation between the Nature of Atomic Li Intercalation and Electrochemical Reactivity in TiS2 and TiO2

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Voltage−Composition Profile and Synchrotron X-ray Structural Analysis of Low and High Temperature Li_xCoO₂ Host Material

Theoretical Study on the Correlation between the Nature of Atomic Li Intercalation and Electrochemical Reactivity in TiS₂ and TiO₂