Cathode active material and lithium secondary battery comprising the same

Patent metadata

Field	Value
Publication number	US-9780371-B2
Application number	US-201313780934-A
Country	US
Kind code	B2
Filing date	Feb 28, 2013
Priority date	Sep 17, 2010
Publication date	Oct 3, 2017
Grant date	Oct 3, 2017

Abstract

Disclosed is a cathode active material for secondary batteries comprising one or more compounds having a layered-crystal structure, represented by the following Formula 1, wherein a transition metal layer contains Li, in an amount lower than 20%, based on a total amount of a transition metal site, and a ratio of Ni positioned in a lithium layer, that is, a cation mixing ratio is 1% to 4.5%, based on a total amount of a lithium site in the lithium layer to stably support the layered-crystal structure: (1-s-t)[Li(Li a Mn (1-a-x-y) Ni x Co y )O 2 ]*s[Li 2 CO 3 ]*t[LiOH] (1), wherein 0<a<0.2; 0<x<0.9; 0<y<0.5; a+x+y<1; 0<s<0.03; and 0<t<0.03. The cathode active material exhibits long lifespan and superior stability at room temperature and high temperatures in spite of repeated charge and discharge at a high current.

First claim

The invention claimed is:

1. A cathode active material for secondary batteries comprising one or more compounds having a layered-crystal structure, represented by the following Formula 1, wherein a transition metal layer contains Li, in an amount lower than 20%, based on a total amount of a transition metal site, and an amount of Ni positioned in a lithium layer is 1.5% to 4.0%, based on a total amount of lithium sites in the lithium layer to stably support the layered-crystal structure, and
wherein a lithium secondary battery comprising the cathode active material exhibits a cycle capability of 92% to 97% after the 30 th cycle compared to the 1 st cycle:
(1- s - t )[Li(Li a (Mn (1-a-x-y) Ni x Co y ) 1-a )O 2 ]*s [Li 2 CO 3 ]*t [LiOH]  (1)

wherein 0<a<0.2; 0<x<0.9; 0<y<0.5; a+x+y<1; 0.0010≦s<0.0022, 0.0012≦t<0.0026, 0.0022≦s+t<0.0048, and a, x and y represent molar ratios, and s and t represent weight ratios.

2. The cathode active material according to claim 1 , wherein a is 0.01 to 0.19.

3. The cathode active material according to claim 1 , wherein x is not lower than 0.3 and is lower than 0.8.

4. The cathode active material according to claim 1 , wherein y is greater than 0 and is not higher than 0.3.

5. The cathode active material according to claim 1 , wherein the transition metal is substituted in a predetermined amount by a metal or non-metal element having a 6-coordination structure.

6. The cathode active material according to claim 5 , wherein a substitution amount of the metal or non-metal element having a 6-coordination structure is 10 mol % or less, based on the total weight of the transition metal.

7. The cathode active material according to claim 1 , wherein Ni positioned in the lithium layer is Ni 2+ derived from the transition metal layer.

8. A cathode mix comprising the cathode active material according to claim 1 .

9. A cathode for secondary batteries in which the cathode mix according to claim 8 is applied to a current collector.

10. A lithium secondary battery comprising the cathode for secondary batteries according to claim 9 .

11. A middle- or large-sized battery pack comprising the secondary battery according to claim 10 as a unit battery.

12. An electric vehicle, a hybrid electric vehicle or a plug-in hybrid electric vehicle comprising the middle- or large-sized battery pack of claim 11 .

Assignees

• Lg Chemical Ltd

Inventors

• Chang Sung-Kyun
• Park Sin Young
• Lim Jinhyung
• Park Hong Kyu

Classifications

• Y02E60/10

  Energy storage using batteries · CPC title

• C01P2006/40

  Electric properties · 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

• C01P2002/20

  Two-dimensional structures · CPC title

• H01M4/362

  Composites · CPC title