| 摘要 |
A lithium composite oxide (LiaNi(1-x-y)CoxMyO2, where M is at least one metal atom selected from the group consisting of Al, Ca, Mg and B, a=0.97~1.05, x=0.1~0.3, and y=0~0.05), prepared by a method including the steps of: (a) coprecipitating a Ni-Co composite hydroxide by adding an aqueous ammonia solution as a complexing agent, and an alkaline solution as a pH-adjusting agent, to an aqueous mixed solution containing a cobalt salt and a nickel salt; (b) adding lithium hydroxide to the composite hydroxide and thermally treating the mixture at 280~420� C.; and (c) thermally treating the resultant of the step (b) at 650~750� C. The average particle diameter of the lithium composite oxide decreases, or the tap density thereof increases, depending on the coprecipitation time. When the lithium composite oxide is used as a positive electrode active material, a lithium ion secondary cell having a high capacity can be obtained. |
