Cathode active material for lithium secondary battery, method for preparing same, and lithium secondary battery comprising same

Patent metadata

Field	Value
Publication number	US-11894554-B2
Application number	US-201716320057-A
Country	US
Kind code	B2
Filing date	Aug 22, 2017
Priority date	Aug 23, 2016
Publication date	Feb 6, 2024
Grant date	Feb 6, 2024

Abstract

Provided are a cathode active material for a lithium secondary battery, a method for preparing the same, and a lithium secondary battery comprising the same. The cathode active material for a lithium secondary battery comprises: a lithium metal compound; and a lithium compound disposed on the surface of the lithium metal compound, wherein the content of lithium contained in the lithium compound is 0.25 parts by weight or less with respect to 100 parts by weight of the lithium metal compound, wherein the specific surface area of the lithium compound is between 0.5 m 2 /g and 2.0 m 2 /g, and the pH of the lithium compound is between 11.5 and 12.3.

First claim

The invention claimed is:

1. A cathode active material for a lithium secondary battery, the cathode active material comprising:
a lithium metal compound and a lithium compound on a surface of the lithium metal compound,
wherein the lithium metal compound is different from the lithium compound,
the content of lithium contained in the lithium compound is 0.25 parts by weight or less with respect to 100 parts by weight of the lithium metal compound,
a specific surface area of the cathode active material is 0.5 m 2 /g to 2.0 m 2 /g, and
a pH of the cathode active material is 11.5 to 12.1.

2. The cathode active material of claim 1 , wherein the content of lithium contained in the lithium compound is 0.05 parts by weight to 0.25 parts by weight with respect to 100 parts by weight of the lithium metal compound.

3. The cathode active material of claim 1 , wherein the specific surface area of the cathode active material is 0.5 m 2 /g to 1.90 m 2 /g.

4. The cathode active material of claim 1 , wherein the pH of the cathode active material is 11.5 to 11.8.

5. The cathode active material of claim 1 , wherein the lithium metal compound comprises a nickel-based oxide represented by Chemical Formula 1:
Li a (Ni x M′ y M″ z )O 2   [Chemical Formula 1]

wherein, in Chemical Formula 1,
M′ is at least one selected from Co, Mn, Ni, Al, Mg, and Ti, M″ is at least one selected from Ca, Mg, Al, Ti, Sr, Fe, Co, Mn, Ni, Cu, Zn, Y, Zr, Nb, and B, 0.8<a≤1.2, 0.6≤x≤1, 0≤y≤0.4, 0≤z≤0.4, and x+y+z=1.

6. The cathode active material of claim 5 , wherein Chemical Formula 1 is a lithium nickel-based oxide represented by Chemical Formula 2:
Li a (Ni x CO y M″ z )O 2   [Chemical Formula 2]

wherein, in Chemical Formula 2,
M″ is at least one element selected from Al and Mn,
0.8<a≤1.2, 0.6≤x≤1, 0≤y≤0.4, 0≤z≤0.4, and x+y+z=1.

7. The cathode active material of claim 1 , wherein the lithium compound comprises Li 2 CO 3 , LiOH, or a combination thereof.

8. A lithium secondary battery comprising a cathode comprising the cathode active material of claim 1 .

9. A method for preparing a cathode active material for a lithium secondary battery, the method comprising
washing a first active material with ammonia water to obtain a second active material, the second active material comprising a lithium metal compound and a lithium compound on a surface of the lithium metal compound,
wherein the lithium metal compound is different from the lithium compound,
the content of lithium contained in the lithium compound is 0.25 parts by weight or less with respect to 100 parts by weight of the lithium metal compound,
a specific surface area of the cathode active material is 0.5 m 2 /g to 2.0 m 2 /g, and
a pH of the cathode active material is 11.5 to 12.1.

10. The method of claim 9 , wherein the ammonia water comprises water and ammonia in a weight ratio of 50:50 to 99:5.

11. The method of claim 9 , wherein pH of the ammonia water is 11 to 13.

Assignees

• Samsung Sdi Co Ltd

Inventors

• Han Jungmin
• Kim Kihyun
• Lee Jaeho
• Hong Ming-Zi

Classifications

• H01M4/505 Primary

  of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy · CPC title

• H01M4/382

  Lithium (H01M4/405 takes precedence) · CPC title

• H01M4/525

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

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M4/131 Primary

  Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title