LixCo0.4Ni0.3Mn0.3O2 electrode materials: Electrochemical and structural studies

Abstract LiCo0.4Ni0.3Mn0.3O2 layered oxide in a member of the LiCo1−2xNixMnxO2 solid solution between LiCoO2 and LiNi0.5Mn0.5O2. Compositions from this solid solution have attracted much attention and have been extensively studied as promising cathode candidates to replace the most popular LiCoO2 cathode material used in the commercial lithium-ion batteries (LiBs). LiCo0.4Ni0.3Mn0.3O2 positive electrode material was prepared via the combustion method followed by a thermal treatment at 900°C for 12h. This material was characterized by a high homogeneity and a granular shape. The Rietveld refinement evidenced that the structure of this compound exhibits no Ni/Li disorder revealing that the LiCo1−2xNixMnxO2 system presents the ideal structure for LiBs application when x<0.4. The electrochemical performances of the LiCo0.4Ni0.3Mn0.3O2 sample were measured at different current rates in the 2.7–4.5V potential range. Its discharge capacity reached 178, 161 and 145mAhg−1 at C/20, 1C and 2C, respectively. Structural changes in LiCo0.4Ni0.3Mn0.3O2 upon delithiation were studied using ex situ X-ray diffraction. A continuous solid solution with a rhombohedral symmetry was detected in the whole composition range. This structural stability during the cycling combined with the obtained electrochemical features make this material convenient for the LiBs applications.