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

Abstract

Samples of Li x CoO 2 (0.5≤x≤1) have been prepared by electrochemical deintercalation from high temperature LiCoO 2 and are characterized by X-ray diffraction, electrical measurements and 7 Li MAS NMR spectroscopy. X-Ray diffraction studies as a function of x are in good agreement with literature data and suggest that the two-phase domain for 0.75≤x≤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. 7 Li MAS NMR suggests that the metal-non metal transition is the driving force for the existence of the biphasic domain.