| abstract |
Disclosed is a lithium-containing composite oxide for a positive electrode of a lithium secondary battery, which has a high capacity density, is highly safe, and has excellent charge/discharge cycle durability and charge/discharge rate property. Also disclosed is a method for producing the lithium-containing composite oxide. Specifically disclosed is a lithium-containing composite oxide represented by the general formula: LipNxMyOzFa [wherein N represents at least one element selected from the group consisting of Co, Mn and Ni; M represents at least one element selected from the group consisting of transition metal elements excluding Co, Mn and Ni, Al, Sn and alkali earth metal elements, and p, x, y, z and a satisfy the following formulae: 0.9 ≤ p ≤ 1,2, 0.965 ≤ x < 2.00, 0 < y ≤ 0.035, 1.9 ≤ z ≤ 4.2, and 0 ≤ a ≤ 0.05], wherein, when a powder of the lithium-containing composite oxide is classified into smaller particles having an average particle diameter Ds50 satisfying the formula: 2 μm ≤ Ds50 ≤ 8 μm and larger particles having an average particle diameter Dl50 satisfying the formula: 10 μm ≤ Dl50 ≤ 25 μm, the content of the smaller particles is 15 to 40 wt% and the content of the larger particles is 60 to 85 wt%, the ratio (ys) of the element M in the general formula above in the smaller particles satisfies the following formula: 0.01 ≤ ys ≤ 0.06, the ratio (yl) of the element M in the general formula above in the larger particles satisfies the following formula: 0 ≤ yl ≤ 0.02, and the ratios ys and yl satisfy the following formula: 0 ≤ yl/ys < 1. |