Enhanced High-Temperature Performance of LiNi0.6Co0.2Mn0.2O2 Positive Electrode Materials by the Addition of nano-Al2O3 during the Synthetic Process

High Ni content layered oxide materials for the positive electrode in lithium-ion batteries have high specific capacity. However, their poor electrochemical and thermal stability at elevated temperature restrict the practical use. A small amount of Al2O3 was added to the mixture of transition metal hydroxide and lithium hydroxide. The LiNi0.6Co0.2Mn0.2O2 was simultaneously doped and coated with Al2O3 during heat-treatment. Electrochemical characteristics of modified LiNi0.6Co0.2Mn0.2O2 were evaluated by the galvanostatic cycling and the LSTA(linear sweep thermmametry) at the constant voltage conditions. The nano-sized Al2O3 added materials show better cycle performance at elevated temperature than that of micro-sized Al2O3. As the added amount of nano-Al2O3 increased, the thermal stability of electrode also enhanced, but the use of 2.5 mol% Al showed the best high temperature performance.