Positive electrode active material for lithium secondary battery and method for preparing the same

Patent metadata

Field	Value
Publication number	US-11424447-B2
Application number	US-201816496167-A
Country	US
Kind code	B2
Filing date	Nov 22, 2018
Priority date	Nov 22, 2017
Publication date	Aug 23, 2022
Grant date	Aug 23, 2022

Abstract

A positive electrode active material for a lithium secondary battery is provided having a secondary particle formed by agglomerating a plurality of polycrystalline primary particles including a lithium composite metal oxide of Chemical Formula 1, wherein an average crystallite size of the primary particle is 180 to 400 nm, a particle size D50 of the primary particle is 1.5 to 3μm, and the primary particle is doped or surface-coated with at least one element M selected from the group consisting Al, Ti, Mg, Zr, Y, Sr, and B in an amount of 3,800 to 7,000 ppm:Lia(NixMnyCozAw)O2+b   [Chemical Formula 1].

First claim

The invention claimed is:

1. A positive electrode active material for a lithium secondary battery, the positive electrode active material comprises a secondary particle formed by agglomerating a plurality of polycrystalline primary particles comprising a lithium composite metal oxide of Chemical Formula 1,
wherein the lithium composite metal oxide of Chemical Formula 1 has a layered crystal structure,
wherein an average crystallite size of the primary particles is 180 to 400 nm, a particle size D50 of the primary particle is 1.5 to 3 μm, and the primary particle is doped or surface-coated with at least one element M selected from the group consisting of Al, Ti, Mg, Zr, Y, Sr, and B in an amount of 3,800 to 7,000 ppm,
wherein a particle size D10 of the secondary particle is 8 μm or more, wherein a particle size D50 of the secondary particle is 10 to 16 μm, and a ratio of D50/D10 is 1.25 to 1.55:
Li a (Ni x Mn y Co z A w )O 2+b   [Chemical Formula 1]

in Chemical Formula 1,
A is at least one element selected from the group consisting of W, V, Cr, Nb, and Mo, and
0.95≤a≤1.2, 0≤b≤0.02, 0<x<1, 0<y≤0.4, 0<z<1, 0≤w<0.2, and x+y+z+w=1.

2. The positive electrode active material of claim 1 , wherein in Chemical Formula 1, a=1, 0≤b≤0.02, 0.5<x<1, 0.1≤y<0.4, 0.1≤z<0.4, 0≤w≤0.05, and x+y+z+w=1.

3. The positive electrode active material of claim 1 , wherein the lithium composite metal oxide of Chemical Formula 1 is selected from the group consisting of LiNi 0.8 Co 0.1 Mn 0.1 O 2 , LiNi 0.6 Co 0.2 Mn 0.2 O 2 , LiNi 0.5 Co 0.2 Mn 0.3 O 2 , and LiNi 0.5 Co 0.3 Mn 0.2 O 2 .

4. The positive electrode active material of claim 1 , wherein the at least one element M is Zr, Mg, Ti, or Al.

5. The positive electrode active material of claim 1 , wherein the particle size D50 of the primary particle is 2 to 3 μm.

6. The positive electrode active material of claim 1 , wherein the at least one element M is doped or doped and surface-coated in an amount of 4,000 to 6,500 ppm based on a total weight of the positive electrode active material.

7. The positive electrode active material of claim 1 , wherein a specific surface area of the positive electrode active material is 0.25 to 0.39 m 2 /g, a pellet density of the positive electrode active material is 3 to 5 g/cc, and a content of an excess lithium based on a total weight of the positive electrode active material is 0.15 to 0.2 wt %.

8. The positive electrode active material of claim 1 , wherein a particle size D10 of the secondary particle is 8 to 10 μm.

9. A method for preparing the positive electrode active material for a lithium secondary battery of claim 1 , comprising:
mixing a precursor for preparation of a lithium composite metal oxide of Chemical Formula 1 with a lithium raw material and a raw material of an element M, wherein the element M is at least one element selected from the group consisting of Al, Ti, Mg, Zr, Y, Sr, and B, and excessively calcining the mixture at a temperature of 960° C. or more;
wherein a particle size D50 of the precursor is 8 μm or more:
Li a (Ni x Mn y Co z A w )O 2+b   [Chemical Formula 1]

in Chemical Formula 1, A is at least one element selected from the group consisting of W, V, Cr, Nb, and Mo, and 0.95≤a≤1.2, 0≤b≤0.02, 0<x<1, 0<y≤0.4, 0<z<1, 0≤w<0.2, and x+y+z+w=1.

10. The method of claim 9 , wherein the particle size D50 of the precursor is 8 to 12 μm.

11. The method of claim 9 , wherein the precursor and the lithium raw material are mixed so that a mole ratio of lithium (Li) included in the lithium raw material to a total number of moles of metal elements in the precursor, not including lithium, is 1.05 to 1.2.

12. The method of claim 9 , wherein the excessively calcining is performed at 990 to 1,050° C.

13. The method of claim 9 , wherein the raw material of the element M is further added and the mixture is excessively calcined when the precursor and the lithium raw material are mixed before the lithium composite metal oxide is mixed with the raw material of the element M and the heat treatment is performed.

14. A method for preparing the positive electrode active material for a lithium secondary battery of claim 1 , comprising
mixing a precursor for preparation of a lithium composite metal oxide of Chemical Formula 1 with a lithium raw material,
excessively calcining the mixture at a temperature of 960° C. or more,
mixing the lithium composite metal oxide thus obtained with a raw material of an element M, wherein the element M is at least one element selected from the group consisting of Al, Ti, Mg, Zr, Y, Sr, and B, and
performing a heat treatment at a temperature of 200 to 800° C. forming a coated layer including the element M,
wherein a particle size D50 of the precursor is 8 to 12 μm:
Li a (Ni x Mn y Co z A w )O 2+b   [Chemical Formula 1]

wherein, A is at least one element selected from the group consisting of W, V, Cr, Nb, and Mo, and 0.95≤a≤1.2, 0≤b≤0.02, 0<x<1, 0<y≤0.4, 0<z<1, 0≤w<0.2, and x+y+z+w=1.

15. The method of claim 14 , wherein the excessively calcining is performed at 990 to 1,050° C.

16. A positive electrode for a lithium secondary battery comprising the positive electrode active material of claim 1 .

17. A lithium secondary battery comprising the positive electrode active material of claim 1 .

Assignees

• Lg Chemical Ltd
• Lg Energy Solution Ltd

Inventors

• Park Younguk
• Yoo Tae Gu
• Hwang Jintae
• Jung Wang Mo
• Park Sungbin

Classifications

• C01G53/82 Primary

  Compounds containing nickel, with or without oxygen or hydrogen, and containing two or more other elements · CPC title

• H01M4/505

  of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy · CPC title

• H01B1/08

  oxides · CPC title

• H01M4/485

  of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy (H01M4/505, H01M4/525 take precedence) · CPC title

• C01P2002/54

  one element only · CPC title