New layered structure obtained by electrochemical deintercalation of the metastable LiCoO2 (O2) variety

Mendiboure, A.; Delmas, Claude; Hagenmuller, Paul

doi:10.1016/0025-5408(84)90204-6

Cited by 101 publications

(74 citation statements)

References 8 publications

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“…Chemical oxidation is known to be useful to remove cations in the structure and NO 2 + is potentially effective oxidizing agent in acetonitrile solution [15][16][17][18]. They can oxidize not only protons in conjunction with Mn 3+ ions but also protons near Mn vacancies in the structure.…”

Section: Introductionmentioning

confidence: 98%

Chemically oxidized manganese dioxides for lithium secondary batteries

Jung¹,

Sakamoto²,

Pitteloud³

et al. 2007

Journal of Power Sources

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Section: Introductionmentioning

confidence: 98%

Chemically oxidized manganese dioxides for lithium secondary batteries

Jung¹,

Sakamoto²,

Pitteloud³

et al. 2007

Journal of Power Sources

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“…Further lithium deintercalation leads to the O6 phase (0.33 ≤ x < 0.42) (S.G. R-3m), that was first characterized with XRD by Mendiboure et al [3]. This stacking exhibits two types of CoO 2 layers and the possibility of Co 3+ /Co 4+ ordering over these layers has been inferred from XRD Rietveld refinement [5].…”

Section: The O6 Structurementioning

confidence: 95%

“…The Rietveld refinement of the neutron diffraction pattern of O2-LiCoO 2 (S.G. P6 3 mc) indicated that the repulsion between lithium and cobalt ions through the common face of their octahedra is strong enough to displace them from the center of their octahedra [2]. Whereas O3-LiCoO 2 has been extensively studied as positive electrode in lithium batteries, to our knowledge, very few papers deal with the O2-LiCoO 2 system [3][4]. During lithium deintercalation, this system exhibits several reversible voltage plateaus, which are associated with phase transformations involving either CoO 2 sheet gliding or lithium/vacancy ordering.…”

Section: Introductionmentioning

confidence: 99%

Lithium electrochemical deintercalation from O2-LiCoO₂: structural study and first principles calculations

Carlier¹,

Ven²,

Ceder³

et al. 2002

MRS Proc.

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We present a detailed study of the O2-LiCoO 2 phase used as positive electrode in lithium batteries. This phase is a metastable form of LiCoO 2 and is prepared by ionic exchange from P2-Na 0.70 CoO 2 . The O2-LiCoO 2 system presents interesting fundamental problems as it exhibits several phase transformations upon lithium deintercalation that imply either CoO 2 sheet gliding or lithium/vacancy ordering. Two unusual structures are observed: T # 2 and O6. The T # 2 phase was characterized by X-ray, neutron and electron diffraction, whereas the O6 phase was only characterized by XRD.In order to better understand the structures and the driving forces responsible for the phase transformations involved in lithium deintercalation, we combine our experimental study of this system with a theoretical approach. The voltage-composition curve at room temperature is calculated using Density Functional Theory combined with Monte Carlo simulations, and is qualitatively in good agreement with the experimental voltage curve over the complete lithium composition range. Pseudopotential and thermodynamic calculations both show that two tetrahedral sites have to be considered for Li in the T # 2 structure. The calculated voltage curve thus exhibits a two-phase O2/T # 2 region that indicates that this phase transformation is driven by the entropy maximization and not by a non-metal to metal transition. We also predict two ordered phases for Li 1/4 CoO 2 (O2) and Li 1/3 CoO 2 (O6) and show that the formation of the O6 phase is not related to Li staging or Co 3+ /Co 4+ charge ordering.

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“…LixCoO2 for x ~ 1 was prepared by thermal decomposition of a pelletized mixture of stoichiometric amounts of Li2CO3 and COCO3 at 900~ as described previously (1)(2)(3)(4)(5). For these solvents Karl Fischer titrations indicated water contents less than 20 600 ppm, and electrolytic conductances less than 1.7 • 10 -8 S cm -z. LiAsF6 (LaRoche "Lectrosalt")was dried at 60~ under vacuum for 24h, and not further treated.…”

Section: Methodsmentioning

confidence: 99%

An Improved Li / Li x CoO2 Rechargeable Cell

Plichta

Slane

Uchiyama

et al. 1989

J. Electrochem. Soc.

149

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Improvement of the cycling behavior of the Li/Li=CoO2 cell has been brought about by the use of esters and alkyl carbonate-based mixed solvents, and by physical modifications of the cathode structure. Binary solvent mixtures of methyl formate with either dimethyl carbonate, diethyl carbonate, or CO2 and LiAsF6 electrolyte exhibit superior resistance towards solvent oxidation as well as improved lithium cycling efficiencies. Use of these mixed solvents with newly developed thin cathodes has resulted in stable Li/Li=CoO2 cells which can be cycled more than 100 times at current densities of 1-10 mA cm -2, and at an average cell discharge voltage of between 3.9 and 3.7V. Due to the high rate of solid-state diffusion of Li § the LixCoO2 cathode can be charged at rates of up to 2 mAcm -2 over at least 100 deep charge and discharge cycles.

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New layered structure obtained by electrochemical deintercalation of the metastable LiCoO2 (O2) variety

Cited by 101 publications

References 8 publications

Chemically oxidized manganese dioxides for lithium secondary batteries

Chemically oxidized manganese dioxides for lithium secondary batteries

Lithium electrochemical deintercalation from O2-LiCoO₂: structural study and first principles calculations

An Improved Li / Li x CoO2 Rechargeable Cell

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New layered structure obtained by electrochemical deintercalation of the metastable LiCoO2 (O2) variety

Cited by 101 publications

References 8 publications

Chemically oxidized manganese dioxides for lithium secondary batteries

Chemically oxidized manganese dioxides for lithium secondary batteries

Lithium electrochemical deintercalation from O2-LiCoO2: structural study and first principles calculations

An Improved Li / Li x CoO2 Rechargeable Cell

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Product

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Lithium electrochemical deintercalation from O2-LiCoO₂: structural study and first principles calculations