Electronic structure of the transition metal ions in LiCoO2, LiNiO2 and LiCo0.5Ni0.5O2

Montoro, Luciano A.; Abbate, M.; Almeida, E.C.; Rosolen, José Maurício

doi:10.1016/s0009-2614(99)00650-8

Cited by 105 publications

(84 citation statements)

References 16 publications

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“…Following the same reasoning for LiNiO 2 , however, requires the formation of Ni 3+ , an uncommon state for solid state nickel oxides and one that is often stabilized by the formation of defects or hydroxides that produce mixed Ni 2+ /Ni 3+ oxidation states. Indeed, two general descriptions have emerged in the literature in relation to the chemical nature of nickel in LiNiO 2 , one analogous to that found for LiCoO 2 in which the oxidation state for the nickel is Ni 3+ [23], [24], [25], [26], [27] and [28] and a second one that relies on localized Ni 2+ -O − pairs in which charge is transferred from a neighboring lattice oxygen onto the nickel to preserve, or at least more closely approximate, the favored 2 + state [29], [30], [31], [32], [33] and [34]. We present here a study of surface composition of LiCoO 2 , LiNiO 2 and LiNi 0.5 Co 0.5 O 2 which suggests that, at least in the near-surface region, the nickel-containing lithium metal oxide is stabilized by dilithiation to produce a nickel cation with an average electron density closer to that of the more favored Ni 2+ state.…”

Section: Introductionmentioning

confidence: 97%

Surface properties of LiCoO2, LiNiO2 and LiNi1−xCoxO2

Moses

Flores

Kim

et al. 2007

Applied Surface Science

173

126

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Section: Introductionmentioning

confidence: 97%

Surface properties of LiCoO2, LiNiO2 and LiNi1−xCoxO2

Moses

Flores

Kim

et al. 2007

Applied Surface Science

173

126

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“…In the case of Ni 2+ , the GS configuration is (2 p) 6 (φ 3d ) 8 and the ES configuration is (2 p) 5 (φ 3d ) 9 . Therefore, fourteen electrons and sixteen orbitals were treated explicitly.…”

Section: Electronic Configurationsmentioning

confidence: 99%

First-principles Calculation of Transition-metal L<SUB>2,3</SUB>-edge Electron-energy-loss Near-edge structures Based on Direct Diagonalization of the Many-electron Hamiltonian

et al. 2002

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First-principles relativistic configuration-interaction (CI) calculations of cation L 2,3 -edge electron-energy-loss near-edge structures (ELNES) of SrTiO 3 , NiO and CaF 2 have been carried out based on the direct approach where the ground state (GS) configuration and the excited state (ES) configuration were calculated simultaneously by direct diagonalization of the many-electron Hamiltonian. The obtained theoretical spectra were compared with our recent results based on the indirect approach where the GS configuration and the ES configuration were calculated separately and their energy separation was adjusted to the value predicted by the Slater's transition-state calculation. Although both approaches well reproduced the overall features of the experimental spectra, the direct approach tend to slightly overestimate the absolute transition energies. In the case of Ti L 2,3 -edge of SrTiO 3 , however, the absolute transition energies calculated by the direct approach were comparable to those by the indirect approach and were also in good agreement with experimental values, indicating sufficient inclusion of electron correlations through pure configuration interactions.

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“…Thus, the stability of structure of LiCoO 2 is the most important parameter for obtaining good electrochemical performance and by stabilizing the structure it might be possible to extract lithium beyond the value realized. Accordingly, several efforts have been directed towards substituting cobalt by different transition elements such as Ni, Mn, Cr, and Fe [11][12][13][14][15][16][17][18]. In addition, extensive studies have also been carried out to substitute Co 3+ in LiCoO 2 with non-transition elements like Mg 2+ [8,9,19], B 3+ [20,21], Al 3+ [22,23], but only a marginal increase in cell potential from 4.2 to 4.3 V has been reported with associated capacity fading.…”

Section: Introductionmentioning

confidence: 99%