Lithium complex oxide for lithium secondary battery positive active material and method of preparing the same

1. A lithium complex oxide secondary particle formed by coagulation of a plurality of primary particles,

wherein an interplanar distance of a crystalline structure in said primary particles decreases toward a surface from a center of the secondary particle,

wherein the secondary particle has a ratio of peak intensity (I 531 ) around 531 eV and peak intensity (I 528 ) around 528.5 eV during an O 1s core-level spectrometry that is obtained through XPS measurement, and

wherein the ratio is I 531 /I 528 ≤2,

wherein the secondary particle has a ratio between peak intensity (I 289 ) around 289 eV and peak intensity (I 284 ) around 284.5 eV during a C is core-level spectrometry that is obtained through XPS measurement, and

wherein the ratio is I 289 /I 284 ≤0.9, and

wherein the surface of the secondary particle includes a LiCoO 2 coating layer.

2. The lithium complex oxide secondary particle of claim 1 , wherein an interplanar distance of the crystalline structure in said primary particles at the center of the secondary particle, d 1 , is configured to be equal to or larger than 4.8 nm.

3. The lithium complex oxide secondary particle of claim 1 , wherein an interplanar distance of the crystalline structure in said primary particles on the surface of the secondary particle, d 2 , is configured to be equal to or smaller than 4.7 nm.

4. The lithium complex oxide secondary particle of claim 1 , wherein the lithium complex oxide secondary particle is configured in a hexagonal structure, and

wherein a lithium ion pathway in said primary particles is formed toward the center from the surface of the secondary particle.

5. The lithium complex oxide secondary particle of claim 1 ,

wherein a thickness of the surface of the secondary particle is 0.3 to 1 μm.

6. The lithium complex oxide secondary particle of claim 1 , wherein the secondary particle has a bound energy (P 1 ) of spin-orbit-spit 2p3/2 peak and a bound energy (P 2 ) of 2p 1 / 2 peak in a Co 2p core-level spectrometry obtained through XPS measurement, and

wherein the P 1 and the P 2 are ranged respectively in 779eV≤P 1 ≤780eV and 794eV≤P 2 ≤795eV.

7. The lithium complex oxide secondary particle of claim 1 , wherein the secondary particle is given by the following Formula 1

Li X1 Ni 1−(x1+y1+z1+r1) Co x1 M 1 y1 M 2 z1 M 3 r1 O a ,  [Formula 1]

wherein, in the Formula 1, M 1 is Mn or Al, and M 2 is Co, and M 3 is selected from a group of Al, Ba, B, Co, Ce, Cr, F, Li, Mg, Mn, Mo, P, Sr, Ti, and Zr, and

wherein 0.95≤X 1 ≤1.05, 1.50 ≤a ≤2.1, 0.02x 1 ≤0.25, 0.01y 1 ≤0.20, 0<z 1 ≤0.20, and 0≤r 1 ≤0.20.

8. A method of preparing a lithium complex oxide secondary particle of claim 1 , the method comprising:

manufacturing precursors of lithium secondary battery positive active material given by the following Formula 2,

Ni 1−(x2+y2) Co x2 M 1 y2 (OH) 2 ,

wherein, in Formula 2, M 1 is Mn or Al, and wherein 0≤x 2 ≤0.25, and 0≤y 2 ≤0.20;

reacting the precursors of lithium secondary battery positive active material with a lithium compound and manufacturing a positive active material by a first thermal treatment;

washing the positive active material with distilled water or an alkaline solution;

reactively coating the washed positive active material with a solution containing M 2 with distilled water or an alkaline solution, wherein M 2 is Co;

drying particles of the positive active material; and

mixing the dried positive active material with M 3 selected from the group of Al, Ba, B, Co, Ce, Cr, F, Mg, Mn, Mo, P, Sr, Ti, and Zr and doping the M 3 into the particles by a second thermal treatment.

9. A lithium secondary battery comprising a lithium complex oxide secondary particle of claim 1 .

10. The lithium secondary battery of claim 9 , wherein the lithium secondary battery is configured to have residual lithium equal to or smaller than 6,000 ppm.