Positive electrode active material for lithium secondary battery comprising lithium metal oxides having multilayered structure and positive electrode comprising the same

Patent metadata

Field	Value
Publication number	US-10741872-B2
Application number	US-201615753097-A
Country	US
Kind code	B2
Filing date	Sep 20, 2016
Priority date	Oct 20, 2015
Publication date	Aug 11, 2020
Grant date	Aug 11, 2020

Abstract

The present invention provides a positive electrode active material for a lithium secondary battery having a core-shell structure which comprises: a core composed of lithium transition metal oxides including nickel(Ni), manganese(Mn) and cobalt(Co); and a shell composed of lithium transition metal oxides including cobalt(Co), wherein an inorganic material layer is further formed by coating on the surface of the shell.

First claim

What is claimed is:

1. A positive electrode active material for a lithium secondary battery having a core-shell structure comprising:
a core composed of lithium transition metal oxides including nickel(Ni), manganese(Mn) and cobalt(Co); and
a shell composed of lithium transition metal oxides including cobalt(Co),
wherein the lithium transition metal oxide of the core is a compound represented by the following Formula 1, and the lithium transition metal oxide of the shell is a compound represented by the following Formula 2:
Li y [Ni a Mn b Co 1−(a+b+c) M c ]O 2   (1)

wherein,
0.55≤a≤0.9, 0.05≤b≤0.5, 0<c≤0.1, a+b+c≤1, 0.98≤y≤1.10; and
M is Zr or Zr and one or more selected from the group consisting of W, B, Al, Ti, Mg, Cr, and Si;
Li y Co (1−a) Z a O 2   (2)

wherein,
0<a≤0.1, 0.98≤y≤1.10; and
Z is Zr or Zr and one or more selected from the group consisting of W, B, Al, Zr, Ti, Mg, Cr, and Si,
wherein an inorganic material layer is further formed by coating on a surface of the shell, and
wherein a content of the inorganic material layer is 0.1 wt % or more to 3.0 wt % or less based on the total weight of the positive electrode active material.

2. The positive electrode active material according to claim 1 , wherein the inorganic material layer includes one or more inorganic elements selected from the group consisting of Al, Ti, Zr, W, Mg, Co, B and Nb.

3. The positive electrode active material according to claim 1 , wherein the inorganic material layer is any one selected from the group consisting of Al 2 O 3 , ZrO 2 , PO 4 , SeO 3 , and SnO 2 .

4. The positive electrode active material according to claim 1 , wherein the inorganic material layer includes an inorganic element of Al.

5. The positive electrode active material according to claim 1 , wherein the content of the inorganic material layer is 1.1 wt % or more to 3.0 wt % or less based on the total weight of the positive electrode active material.

6. The positive electrode active material according to claim 5 , wherein the content of the inorganic material layer is 2.0 wt % or more to 3.0 wt % or less based on the total weight of the positive electrode active material.

7. The positive electrode active material according to claim 1 , wherein the inorganic material layer has a thickness of 1 to 150 nm.

8. The positive electrode active material according to claim 1 , wherein a content ratio between the core and the shell is 20:80 to 80:20 on a weight basis.

9. The positive electrode active material according to claim 1 , wherein the core has a concentration gradient in which a concentration of nickel, manganese, and cobalt decreases toward the outer surface, and the shell has a concentration gradient in which a concentration of cobalt decreases toward the outer surface.

10. The positive electrode active material according to claim 1 , wherein the core has a structure in which a concentration of nickel, manganese, and cobalt is constant without a concentration gradient within a core region, and the shell has a structure in which a concentration of cobalt is constant without a concentration gradient within a shell region.

11. The positive electrode active material according to claim 1 , wherein the positive electrode active material further includes a concentration gradient layer formed between an outside of the core and an inside of the shell, in which a concentration of one or more transition metals continuously changes to exhibit a concentration gradient.

12. The positive electrode active material according to claim 1 , wherein the positive electrode active material has a particle size of 0.1 to 1 μm.

13. The positive electrode active material according to claim 1 , wherein the positive electrode active material is a secondary particle formed by aggregation of primary particles, and a lithium ion diffusion path in the primary particle is formed in the center direction of the secondary particle.

14. A method for producing the positive electrode active material for a lithium secondary battery of claim 1 comprising:
(a) uniformly mixing a precursor for the production of a positive electrode active material having a core-shell structure with lithium oxide, and then performing a calcination reaction to produce a lithium transition metal oxide powder.

15. The method according to claim 14 , wherein the method comprises the steps of:
(b) preparing a mixed solution containing one or more inorganic element selected from the group consisting of Al, Ti, Zr, W, Mg, Co, B and Nb in an organic solvent;
(c) mixing the mixed solution with the prepared lithium transition metal oxide powder and stirring the mixed solution in a paste state;
(d) drying the pasty mixture to evaporate the organic solvent; and
(e) heat-treating the dried mixture to produce a positive electrode active material in which a inorganic material layer is formed on the surface of the lithium transition metal oxide particles.

16. A positive electrode comprising the positive electrode active material according to claim 1 .

17. A lithium secondary battery comprising the positive electrode according to claim 16 .

Assignees

• Lg Chemical Ltd

Inventors

• You Min Kyu
• Shin Ho Suk
• Park Hong Kyu

Classifications

• H01M4/0416

  involving impregnation with a solution, dispersion, paste or dry powder (H01M4/0438 takes precedence) · CPC title

• H01M2004/028

  Positive electrodes · CPC title

• H01M4/48

  of inorganic oxides or hydroxides · CPC title

• H01M4/1391 Primary

  of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title

• H01M4/0471

  involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis · CPC title