Koichi Numata

Synthesis and characterization of layer structured solid solutions in the system of LiCoO2–Li2MnO3

Abstract Lithium-manganese-cobalt oxide, Li(Co 1− x Li x /3 Mn 2 x /3 )O 2 (0≤ x ≤1) was prepared as a solid solution between the two kinds of layer structured end members, LiCoO 2 and Li 2 MnO 3 . Simple calcination of the stoichiometric mixture of the oxide constituents gave a mixture of two end members. Excess lithium carbonate or lithium hydroxide should be added to the mixture on calcination at 900–1000°C to obtain the solid solutions. The excess lithium compounds were removed by washing with water. The results of the X-ray diffraction studies, chemical analysis and XANES measurements suggested that the Co in LiCoO 2 was substituted for (Li 1/3 Mn 2/3 ). The solid solutions were electrochemically active as cathode materials for a lithium battery, though the discharge capacity decreased with the increase of x in Li(Co 1− x Li x /3 Mn 2 x /3 )O 2 .