Patent ID: 11945729
Assignee: NICHIA CORPORATION
Field: Materials, metallurgy (Chemistry)
Classification: CPC C  H  Y | IPC C  H

Claim 0:
1. A positive electrode active material for non-aqueous electrolyte secondary battery comprising a lithium transition metal complex oxide represented by a formula: LiaNi1-x-yCoxMnyMzO2, wherein 0.95≤a≤1.2, 0.10≤x≤0.35, 0≤y≤0.35, 0≤z≤0.05, M is at least one element selected from a group consisting of Al, Mg, Ca, Ti, Zr, Nb, Ta, Cr, Mo, W, Fe, Cu, Si, Sn, Bi, Ga, Y, Sm, Er, Ce, Nd, La, Cd and Lu,
wherein the lithium transition metal complex oxide is in a form of secondary particles formed by agglomeration of primary particles,
wherein the secondary particles comprise:
a first layer having a radial depth ratio of less than 5% from a surface in the secondary particle;
a second layer having a radial depth ratio in a range of 5% to less than 50% and located at an inner side than the first layer in the secondary particles; and
a third layer having a radial depth ratio of 50% or greater and located at an inner side than the second layer in the secondary particles,

wherein a SEM-EDX spectrum of said element M with respect to the radial depth of the secondary particles has a peak in the second layer,
wherein the peak includes a point of maximum coordinate value on a vertical axis among peaks in a CPS curve,
wherein the CPS curve is a plot of a depth ratio in the radial direction to the radius of the secondary particles of the lithium transition metal complex oxide on the horizontal axis and fluorescent X-ray intensity at the depth ratio on the vertical axis, and
wherein assuming that the amount of said element M in the first layer is S4 and that the amount of said element M in the second layer is S5, S4 and S5 satisfy an inequality of S5>1.02 S4.