| 摘要 |
Provided are: a lithium ion secondary battery positive electrode material that has good rate characteristics and cycle characteristics while the density of a positive electrode active material is being increased; a lithium ion secondary battery positive electrode using the same; and a lithium ion secondary battery. The lithium ion secondary battery positive electrode material (1), which is represented by Li1+xM11-x-yM2yO2 [-0.1 ≤ x ≤ 0.3, 0 ≤ y ≤ 0.1, M1 is Ni, Co, or Mn, M2 is Mg, Al, Ti, Zr, Mo, Nb, Fe, or B] and is an aggregate that includes secondary particles (50, 60) in which lithium metal composite oxide primary particles (10) having a layered structure are aggregated, is characterised in that: measured by laser diffraction/scattering particle size distribution, the secondary particles (50, 60) have a (D10) of 0.5-10 µm inclusive and a (D90) that exceeds 10 µm and is equal to or less than 50 µm; and the average porosity of the secondary particles having a particle diameter exceeding 10 µm and equal to or less than 50 µm is higher than the average porosity of the secondary particles having a particle diameter of 0.5-10 µm inclusive. |
