Abstract
The layered oxide LiNi0.6Mn0.2Co0.2O2 is a very attractive positive electrode material, as shown by good reversible capacity, chemical stability and cyclability upon long range cycling in Li-ion batteries and, hopefully, in a near future, in all-solid-state batteries. Three samples with variable primary particle sizes of 240 nm, 810 nm and 2.1 µm in average and very similar structures close to the ideal 2D layered structure (less than 2% Ni2+ ions in Li+ sites) were obtained by coprecipitation followed by solid-state reaction at high temperature. The electrochemical performances of the materials were evaluated in a conventional organic liquid electrolyte in Li-ion batteries and in a gel electrolyte in all-solid-state batteries. The positive electrode/electrolyte interface was analysed by X-Ray photoelectron spectroscopy in order to determine its composition and the extent of the degradation of the lithium salt and the carbonate solvents after cycling, taking into account the changes in particle size of the positive electrode material and the nature of the electrolyte.