Electron transfer mechanisms upon lithium deintercalation from LiCoO2 to CoO2 investigated by XPS

Laurence Dahéron (1) , Rémi Dedryvère (1) , Hervé Martinez (1) , Michel Ménétrier (2) , Cathy Denage (2) , Claude Delmas (2) , Danielle Gonbeau (1)

1 LCTPCM - Laboratoire de Chimie théorique et Physico-chimie moléculaire
2 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux

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.

Mots clés: X-ray photoelectron spectroscopy; Electronic structure; Electron; Lithium deintercalation; Transfer mechanisms; Cobalt lithium oxide; Cobalt dioxide

Domaines: Matériaux

Laurence Dahéron, Rémi Dedryvère, Hervé Martinez, Michel Ménétrier, Cathy Denage, et al.. Electron transfer mechanisms upon lithium deintercalation from LiCoO2 to CoO2 investigated by XPS. Chemistry of Materials, 2008, 20 (2), pp.583-590. ⟨10.1021/cm702546s⟩. ⟨hal-00259325⟩