Prediction of Li intercalation and battery voltages in layered vs. cubic Li{sub x}CoO{sub 2}
- National Renewable Energy Lab., Golden, CO (United States)
It is now possible to use a quantum-mechanical electronic structure theory of solids and derive, completely from first-principles, the voltage of a battery based on intercalation reaction energetics. Using such techniques, the authors investigate the structural stability, intercalation energies, and battery voltages of the two observed ordered phases (layered and cubic) of LiCoO{sub 2}. They perform calculations for not only fully lithiated LiCoO{sub 2}, but also fully delithiated cubic CoO{sub 2} and partially delithiated Li{sub 0.5}CoO{sub 2}. The calculations demonstrate that removal of Li from the cubic phase results in movement of the Li atoms from their original octahedral sites to tetrahedral sites, forming a low-energy LiCo{sub 2}O{sub 4} spinel structure. The energetics of the spinel phase are shown to account for the observed marked differences in battery voltages between the cubic and layered phases of LiCoO{sub 2}. A small energy barrier exists for Li motion between octahedral and tetrahedral sites, thus indicating the metastability of the high-energy octahedral sites. Finally, the authors point out a possible pressure-induced layered to cubic transition in LiCoO{sub 2}.
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC36-83CH10093
- OSTI ID:
- 653386
- Journal Information:
- Journal of the Electrochemical Society, Vol. 145, Issue 7; Other Information: PBD: Jul 1998
- Country of Publication:
- United States
- Language:
- English
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