Positive active material, preparing method thereof, positive electrode for lithium secondary battery including the same, and lithium secondary battery employing the same

Patent metadata

Field	Value
Publication number	US-9601765-B2
Application number	US-201514610804-A
Country	US
Kind code	B2
Filing date	Jan 30, 2015
Priority date	Feb 25, 2014
Publication date	Mar 21, 2017
Grant date	Mar 21, 2017

Abstract

Provided are a positive active material that has a decreased amount of Li-containing impurities that remain on a lithium transition metal composite oxide surface to decrease an amount of gas generation and has improved lifespan properties, a method of preparing the same, a positive electrode for a lithium secondary battery including the positive active material, and a lithium secondary battery including the same.

First claim

What is claimed is:

1. A positive active material comprising:
a lithium transition metal composite oxide core; and
a coating layer comprising LiF in an amount of about 0.001 parts by weight to about 0.2 parts by weight based on 100 parts by weight of the lithium transition metal composite oxide core on at least one portion of a surface of the lithium transition metal composite oxide core,
wherein the amount of Li-containing impurities that remain on a surface of a lithium transition metal composite oxide core is 0.25 parts by weight or less based on 100 parts by weight of the lithium transition metal composite oxide core.

2. The positive active material of claim 1 , wherein the Li-containing impurities comprise lithium carbonate (Li 2 CO 3 ) and lithium hydroxide (LiOH).

3. The positive active material of claim 1 , wherein the coating layer comprises the surface of the lithium transition metal composite oxide core surface treated with at least one of NH 4 F, NH 4 HF 2 , HF, CF 3 COOH, and anhydrous hydrogen fluoride.

4. The positive active material of claim 1 , wherein the coating layer has LiF particles scattered on the surface of the lithium transition metal composite oxide core.

5. The positive active material of claim 1 , wherein the amount of the LiF is about 0.05 parts by weight to about 0.2 parts by weight, based on 100 parts by weight of the lithium transition metal composite oxide core.

6. The positive active material of claim 1 , wherein the thickness of the coating layer is from about 10 nm to about 500 nm.

7. The positive active material of claim 1 , wherein an amount of nickel with respect to a total amount of transition metals comprised in the lithium transition metal composite oxide core is 40 wt % or greater.

8. The positive active material of claim 1 , wherein the lithium transition metal composite oxide core is a lithium transition metal composite oxide represented by Formula 1 below:
Li a Ni b (M1) c (M2) d O 2   <Formula 1>

in Formula 1,
0.9<a≦1.1, 0.5≦b<0.9, 0.1≦c<0.45, and 0≦d<0.15, 0.1≦c+d<0.6, M1 is at least one of Co and Mn, and M2 is at least one of Al, Ti, Mg, Sc, V, Cr, Fe, Co, Mn, Zn, B, Si, Ga, Ge, N, P, As, Zr, Mo, W, Ru, Rh, Pt, Ag, and Sn.

9. The positive active material of claim 1 , wherein the lithium transition metal composite oxide core is a secondary particle in which a plurality of primary particles are aggregated.

10. The positive active material of claim 9 , wherein an average diameter (D50) of the secondary particle is about 3 μm to about 20 μm.

11. A positive electrode for a lithium secondary battery comprising the positive active material according to claim 1 .

12. A lithium secondary battery comprising:
a negative electrode;
a positive electrode comprising:
a lithium transition metal composite oxide core;
a coating layer comprising LiF in an amount of about 0.001 parts by weight to about 0.2 parts by weight based on 100 parts by weight of the lithium transition metal composite oxide core on at least one portion of a surface of the lithium transition metal composite oxide core, and
wherein the amount of Li-containing impurities that remain on a surface of a lithium transition metal composite oxide core is 0.25 parts by weight or less based on 100 parts by weight of the lithium transition metal composite oxide core.

13. The lithium secondary battery of claim 12 , wherein the Li-containing impurities comprise lithium carbonate (Li 2 CO 3 ) and lithium hydroxide (LiOH).

14. The lithium secondary battery of claim 12 , wherein the coating layer comprises the surface of the lithium transition metal composite oxide core surface treated with at least one of NH 4 F, NH 4 HF 2 , HF, CF 3 COOH, and anhydrous hydrogen fluoride.

15. The lithium secondary battery of claim 12 , wherein the coating layer has LiF particles scattered on the surface of the lithium transition metal composite oxide core.

Assignees

• Samsung Sdi Co Ltd

Inventors

• Cho Sang-Woo
• You Yong-Chan
• Kim Chang-Wook
• Park Sang-In

Classifications

• Y02E60/122

  Cross-Sectional Technologies · mapped topic

• Y02P70/54

  Cross-Sectional Technologies · mapped topic

• Y02T10/7011

  Cross-Sectional Technologies · mapped topic

• H01M4/628

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

• H01M4/366 Primary

  as layered products · CPC title