Structure and electrochemistry of lithium cobalt oxide synthesised at 400°C

A novel LiCoO2 compound has been prepared by the reaction of Li2CO3 and CoCO3 at 400°C. Unlike the well-known LiCoO2 structure that is synthesised at higher temperature (900°C) and contains Li+ and Co3+ ions in discrete layers between planes of close-packed oxygen ions, the structure of LiCoO2 (400°C) has approximately 6% cobalt within the lithium layers. The electrochemical properties of LiCoO2 (400°C) differ significantly from LiCoO2 (900°C). Whereas electrochemical extraction from LixCoO2 (900°C) in room-temperature lithium cells takes place as a single-phase reaction above 3.9V for x≤0.9, electrochemical extraction from LixCoO2 (400°C) occurs as a two-phase reaction at an open-circuit voltage of 3.61V for 0.1