Positive active material for rechargeable lithium battery, method of preparing the same and rechargeable lithium battery including the same

Patent metadata

Field	Value
Publication number	US-11757092-B2
Application number	US-201916684057-A
Country	US
Kind code	B2
Filing date	Nov 14, 2019
Priority date	Nov 15, 2018
Publication date	Sep 12, 2023
Grant date	Sep 12, 2023

Abstract

A positive active material for a rechargeable lithium battery includes a lithium nickel-based composite oxide including a secondary particle in which a plurality of plate-shaped primary particles are agglomerated; and a coating layer including a fiber-shaped lithium manganese composite oxide, wherein the fiber-shaped lithium manganese composite oxide is attached to the surface of the lithium nickel-based composite oxide.

First claim

What is claimed is:

1. A positive active material for a rechargeable lithium battery, the positive active material comprising:
a lithium nickel-based composite oxide comprising a secondary particle in which a plurality of plate-shaped primary particles is agglomerated; and
a coating layer comprising a fiber-shaped lithium manganese composite oxide,
wherein the fiber-shaped lithium manganese composite oxide is attached to a surface of the lithium nickel-based composite oxide,
wherein the positive active material comprises unreacted residual lithium on the surface of the lithium nickel-based composite oxide in an amount of less than or equal to about 1,300 ppm;
wherein the residual lithium comprises LiOH and/or Li2CO3; and
wherein a diameter of the fiber-shaped lithium manganese composite oxide is about 2 nm to about 50 nm.

2. The positive active material of claim 1 , wherein the lithium manganese composite oxide is represented by Chemical Formula 1:
x LiMnO 2 ·y Li 4 Mn 5 O 12 ·z LiMn 2 O 4 ·(1- x - y - z )Li 2 MnO 3 ,  Chemical Formula 1

wherein, in Chemical Formula 1, 0≤x<1, 0≤y<1, 0≤z<1, 0<y+z<1 and 0<x+y+z<1.

3. The positive active material of claim 1 , wherein the lithium manganese composite oxide has a cubic crystal lattice structure and a monoclinic crystal lattice structure, or has the cubic crystal lattice structure, the monoclinic crystal lattice structure, and an orthorhombic crystal lattice structure.

4. The positive active material of claim 3 , wherein:
the cubic crystal lattice structure corresponds to at least one selected from LiMn 2 O 4 and Li 4 Mn 5 O 12 ,
the monoclinic crystal lattice structure corresponds to Li 2 MnO 3 , and
the orthorhombic crystal lattice structure corresponds to LiMnO 2 .

5. The positive active material of claim 1 , wherein the coating layer has a thickness of about 2 nm to about 300 nm.

6. The positive active material of claim 1 , wherein the lithium manganese composite oxide is in an amount of about 0.1 wt % to about 5 wt % based on a total weight of the positive active material.

7. The positive active material of claim 1 , wherein the positive active material further comprises lithium manganese composite oxide particles,
wherein the lithium manganese composite oxide particles each have an average particle diameter of less than or equal to 10 μm.

8. The positive active material of claim 1 , wherein the secondary particle has a regular array structure in which (003) planes of the primary particles are oriented in a vertical direction with respect to an outermost surface of the secondary particle.

9. The positive active material of claim 1 , wherein the secondary particle is in a single-centered radial arrangement structure having one center or a multi-centered radial arrangement structure having a plurality of centers.

10. The positive active material of claim 1 , wherein the amount of unreacted residual lithium is less than or equal to about 1,000 ppm.

11. The positive active material of claim 1 , wherein the lithium nickel-based composite oxide has a porosity of about 1% to about 8%.

12. The positive active material of claim 1 , wherein the lithium nickel-based composite oxide has a specific surface area of about 0.3 m 2 /g to about 0.8 m 2 /g.

13. A method of preparing the positive active material of claim 1 , the method comprising:
mixing a metal hydroxide precursor and a lithium source to prepare a first mixture;
first heat-treating the first mixture under a high temperature condition to prepare a first fired product comprising residual lithium;
mixing the first fired product with a manganese-based oxide to prepare a second mixture; and
second heat-treating the second mixture to prepare the positive active material.

14. The method of claim 13 , wherein the first heat-treating is performed at about 650° C. to about 950° C.

15. The method of claim 13 , wherein the manganese-based oxide is mixed in an amount of about 0.1 to about 5 parts by weight based on 100 parts by weight of the first fired product.

16. The method of claim 13 , wherein the second mixture further comprises a second lithium source.

17. A rechargeable lithium battery comprising:
a positive electrode comprising the positive active material of claim 1 ;
a negative electrode; and
an electrolyte between the positive electrode and the negative electrode.

Assignees

• Samsung Sdi Co Ltd

Inventors

• Chang Donggyu
• Kil Donghyun
• Kim Jongmin
• Yang Wooyoung

Classifications

• C01G53/82

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

• H01M4/525 Primary

  of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy · CPC title

• C01G53/50 Primary

  of the type (MnO2)n-, e.g. Li(NixMn1-x)O2 or Li(MyNixMn1-x-y)O2 · CPC title

• H01M4/366 Primary

  as layered products · CPC title

• H01M4/628

  Inhibitors, e.g. gassing inhibitors, corrosion inhibitors · CPC title