Formation of Nanometric HT-LiCoO2 by a Precipitation and Aging Process in an Alcoholic Solution

In this paper, we detailed the formation/evolution of precipitates in alcoholic media containing CoII+ and Li+ species, together with the evolution of the composition and structure/texture of the resulting solid phases during the aging process at controlled constant temperature. While the end product is found to be well-crystallized HT-LiCoO2, its formation is shown to result from a two-step process enlisting the initial fast precipitation of β-HCoO2 and then its slow dissolution followed by recrystallization of the lithium-containing material. These results were obtained through combined X-ray diffraction, Raman and IR spectroscopy, elemental and oxidation-state analysis, and high-resolution transmission electron microscopy/selected-area electron diffraction observations. Depending on the cationic concentration, the size of the precipitated material can be controlled within the nanometric range. The electrochemical performances of these aged materials are slightly improved compared to those of the directly precipitated ones that we previously reported. The main limitation of these materials remains the presence of surface protons.