The insulator-metal transition upon lithium deintercalation from LiCoO2:: electronic properties and 7Li NMR study

Samples of LixCoO2(0.5 less than or equal to x less than or equal to 1) have been prepared by electrochemical deintercalation from high temperature LiCoO2 and are characterized by X-ray diffraction, electrical measurements and Li-7 MAS NMR spectroscopy. X-Ray diffraction studies asa function of x are in good agreement with literature data and suggest that the two-phase domain for 0.75 less than or equal to x less than or equal to 0.94 is not due to structural reasons. Electrical conductivity and thermoelectronic power measurements evidence a gradual change in the electronic properties from localised to delocalised electrons upon lithium deintercalation. Li-7 MAS NMR suggests that the metal-non metal transition is the driving force for the existence of the biphasic domain.