Influence of the Initial Li/Co Ratio in LiCoO on the High-Voltage Phase-Transitions Mechanisms.

The influence of the initial Li/Co stoichiometry in LiCoO (LCO) (1.00 ≤ Li/Co ≤ 1.05) on the phase-transition mechanisms occurring at high voltage during lithium deintercalation ( V > 4.5 vs Li/Li) was investigated by in situ X-ray diffraction. Even if the excess Li in LiCoO does not hinder the formation of the H1-3 and O1 phases, the latter are obtained at higher voltages and exhibit larger c parameters compared with their analogues formed from LiCoO. We also showed that for the stoichiometric LiCoO the deintercalation process is more complex than already reported, with the formation of an intermediate structure between H1-3 and O1.