| abstract |
A nickel-based lithium metal composite oxide containing secondary particles including aggregates of primary particles, wherein the secondary particles have i) a particle size of 14 μm or more and opposite secondary particles containing aluminum (Al) and ii) a particle size of It is 5 μm or less and contains small-grain secondary particles containing manganese (Mn), the manganese content of the opposing secondary particles is small compared to the manganese content of the small-grain secondary particles, and manganese (Mn) is present on the surface of the opposing secondary particles. Provided is a lithium secondary battery including a nickel-based lithium metal composite oxide containing aluminum (Al) on the surface of small secondary particles, a positive electrode including the same, the positive electrode, the negative electrode, and an electrolyte interposed therebetween. |