Cathode active material and lithium secondary battery for controlling impurity or swelling including the same and method of preparing cathode active material with enhanced productivity

Patent metadata

Field	Value
Publication number	US-10096831-B2
Application number	US-201414264588-A
Country	US
Kind code	B2
Filing date	Apr 29, 2014
Priority date	Jan 17, 2012
Publication date	Oct 9, 2018
Grant date	Oct 9, 2018

Abstract

Disclosed are a cathode active material represented by Formula 1 below and including a metal cation having a greater ionic radius than a Ni cation and represented by M of Formula 1 at a Li cation site or in an empty space within a crystal lattice so as to prevent mixing of Ni cations into a Li layer, a lithium secondary battery including the same, and a method of preparing the cathode active material which has improved productivity.

Li a Ni x Mn y Co z M w O 2−t A t   (1)
wherein a, x, y, w, M, A, z, and t are the same as defined in the specification.

First claim

The invention claimed is:

1. A cathode active material represented by Formula 1 below and comprising a metal cation having a greater ionic radius than a Ni cation and represented by M of Formula 1 at a Li cation site or in an empty space within a crystal lattice so as to prevent mixing of Ni cations into a Li layer,
wherein the cathode active material further comprises a Li-containing compound,
wherein an amount of the Li-containing compound is greater than 0 and less than or equal to 0.161 wt % based on a total weight of the cathode active material and the Li-containing compound is Li 2 CO 3 and/or LiOH:
the cathode active material is prepared by a method comprising the steps of sintering a mixture of a transition metal source and a lithium source in air, wherein the mixture comprises an alkaline earth metal source having an oxidation number of +2 so that the sintering is performed at 890° C. to 930° C., and
the alkaline earth metal is Sr or Ba:
Li a Ni x Mn y Co z M w O 2−t A t   (Formula 1)

wherein
0≤a≤1.2, 0<x≤0.9, 0<y≤0.9, 0<z≤0.9, 0<w≤0.3, 2≤a+x+y+z+w≤2.3, x>y, x>z, and 0≤t<0.2;

M is Sr 2+ or Ba 2+ ; and
A is at least one monovalent or divalent anion.

2. The cathode active material according to claim 1 , wherein, in Formula 1, y+z≤0.6.

3. The cathode active material according to claim 2 , wherein, in Formula 1, y+z≤0.44.

4. The cathode active material according to claim 1 , wherein M is Sr +2 .

5. The cathode active material according to claim 1 , wherein M is Ba 2+ .

6. The cathode active material according to claim 1 , wherein the Ni cation is Ni 2+ .

7. The cathode active material according to claim 1 , wherein an X-ray diffraction peak ratio (003)/(014) of the cathode active material of Formula 1 is greater than that of a cathode active material represented by Formula 2 below prepared under the same sintering temperature conditions:
Li a Ni x Mn y Co z O 2−t A t   (2)

wherein
0≤a≤1.2, 0<x≤0.9, 0<y≤0.9, 0<z≤0.9, a+x+y+z=2, x>y, x>z, and 0≤t<0.2;

and
A is at least one monovalent or divalent anion.

8. A cathode mixture for secondary batteries, comprising the cathode active material according to claim 1 .

9. A cathode for secondary batteries in which the cathode mixture according to claim 8 is coated on a current collector.

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

11. The lithium secondary battery according to claim 10 , wherein the lithium secondary battery has a capacity retention ratio with respect to initial capacity of 85% or more at 50 cycles performed under the following conditions: at 45° C., charging at 0.5 C and discharging at 1.0 C.

12. A battery module comprising the lithium secondary battery according to claim 10 as a unit cell.

13. A battery pack comprising the battery module according to claim 12 .

14. A device using the battery pack according to claim 13 as a power source.

Assignees

• Lg Chemical Ltd

Inventors

• Lee Daejin
• Kang Sungjoong
• Jin Joohong
• Park Hong Kyu

Classifications

• C01P2002/72

  by d-values or two theta-values, e.g. as X-ray diagram · CPC title

• C01P2002/52

  containing elements as dopants · CPC title

• C01D15/08

  Carbonates; Bicarbonates · CPC title

• H01M10/052

  Li-accumulators · CPC title

• H01M4/364

  as mixtures · CPC title