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Electron Transfer Mechanisms upon Lithium Deintercalation from LiCoO 2 to CoO 2 Investigated by XPS

2007; American Chemical Society; Volume: 20; Issue: 2 Linguagem: Inglês

10.1021/cm702546s

1520-5002

Laurence Dahéron, Rémi Dedryvère, Hervé Martinez, Michel Ménétrier, C. Denage, Claude Delmas, D. Gonbeau,

Semiconductor materials and interfaces

Lithium deintercalation of LixCoO2 from x = 1 to x ≈ 0 has been carried out electrochemically. The changes in the electronic structure from LiCoO2 to CoO2 have been investigated by X-ray photoelectron spectroscopy (XPS) to bring some new developments about the electron transfer mechanisms upon lithium deintercalation. All available XPS core peaks (Co 2p, Co 3p, Co 3s, O 1s, F 1s, P 2p, C 1s) and valence spectra have been analyzed. The contributions of the electrode material and of the electrode/electrolyte interface have been clearly distinguished. We show that cobalt and oxygen simultaneously undergo a partial oxidation process and that the sole participation of oxygen atoms to the charge transfer process, as it is sometimes assumed, can be excluded. The surface film consists of organic and inorganic species resulting from degradation of the electrolyte.