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

Patent metadata

Field	Value
Publication number	US-10270096-B2
Application number	US-201514971375-A
Country	US
Kind code	B2
Filing date	Dec 16, 2015
Priority date	Dec 17, 2014
Publication date	Apr 23, 2019
Grant date	Apr 23, 2019

Abstract

A positive active material for a rechargeable lithium battery includes a LiCoO 2 particle. An interior of the particle has a layered structure and a surface of the particle has a spinel structure.

First claim

What is claimed is:

1. A positive active material for a rechargeable lithium battery, comprising
a LiCoO 2 particle,
wherein an interior of the particle has a layered structure and a surface of the particle has a spinel structure.

2. The positive active material as claimed in claim 1 , wherein the layered structure is a LiCoO 2 phase, and
the spinel structure is a LiCo 2 O 4 phase.

3. The positive active material as claimed in claim 1 , wherein the LiCoO 2 particle has a true density of about 5.054 g/cm 3 to about 5.070 g/cm 3 .

4. The positive active material as claimed in claim 1 , wherein the LiCoO 2 particle has a particle diameter (D50) of about 15 μm to about 25 μm.

5. The positive active material as claimed in claim 1 , wherein the LiCoO 2 particle has a spherical shape.

6. A method of preparing a positive active material for a rechargeable lithium battery, the method comprising
mixing a Co raw material having a particle diameter (D50) of about 10 μm to about 20 μm and a Li raw material to obtain a mixture; and
heat-treating the mixture,
wherein the heat-treating includes firing the mixture at a first temperature, and, after the firing, maintaining a resultant for a predetermined time at a second temperature lower than the first temperature such that a LiCoO 2 particle is provided wherein an interior of the particle has a layered structure and a surface of the particle has a spinel structure.

7. The method as claimed in claim 6 , wherein:
the first temperature is about 950° C. to about 1050° C., and
the second temperature is about 650° C. to about 850° C.

8. The method as claimed in claim 6 , wherein the predetermined time that the resultant is maintained at the second temperature is about 3 hours to about 6 hours.

9. The method as claimed in claim 6 , wherein the heat-treating further includes maintaining the mixture for a predetermined time at a third temperature before firing the mixture at the first temperature, the third temperature being lower than the first temperature.

10. The method as claimed in claim 9 , wherein:
the first temperature is about 950° C. to about 1050° C., and
the third temperature is about 600° C. to about 700° C.

11. The method as claimed in claim 9 , wherein the predetermined time at which the mixture is maintained at the third temperature is about 3 hours to about 6 hours.

12. The method as claimed in claim 6 , wherein the Co raw material and the Li raw material are mixed such that a mole ratio of Co to Li is about 1:0.98 to about 1:1.02.

13. A rechargeable lithium battery, comprising
a positive electrode including the positive active material as claimed in claim 1 .

Assignees

• Samsung Sdi Co Ltd

Inventors

• Shim Jae-Hyun
• Lee Ki-Soo
• Lee Jae-Han
• Lee Se-Hee
• Ju Hyeon-Ah
• Lee Eun-Cheol
• Song Joo-Han
• Lee Yun-Hee

Classifications

• C01P2004/03

  obtained by SEM · 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

• C01P2006/40

  Electric properties · CPC title

• C01P2006/10

  Solid density · CPC title

• C01P2004/02

  obtained by optical microscopy · CPC title