Method of preparing positive electrode active material for lithium secondary battery and positive electrode active material prepared by the same

Patent metadata

Field	Value
Publication number	US-12278376-B2
Application number	US-202017775694-A
Country	US
Kind code	B2
Filing date	Dec 3, 2020
Priority date	Dec 3, 2019
Publication date	Apr 15, 2025
Grant date	Apr 15, 2025

Abstract

A method of preparing a positive electrode active material includes preparing a lithium transition metal oxide containing nickel in an amount of 60 mol % or more based on a total number of moles of metals excluding lithium, impregnating the lithium transition metal oxide with 300 ppm to 1,000 ppm of moisture based on 100 parts by weight of the lithium transition metal oxide, and performing a heat treatment on the lithium transition metal oxide impregnated with the moisture, wherein a lithium by-product present on a surface of the lithium transition metal oxide and the moisture react to form a passivation layer on the surface of the lithium transition metal oxide. A positive electrode active material prepared by the above-described preparation method, and a positive electrode and a lithium secondary battery which include the positive electrode active material are also provided.

First claim

The invention claimed is:

1. A method of preparing a positive electrode active material, the method comprising:
preparing a lithium transition metal oxide containing nickel in an amount of 60 mol % or more based on a total number of moles of metals excluding lithium;
impregnating the lithium transition metal oxide with 300 ppm to 1,000 ppm of moisture based on 100 parts by weight of the lithium transition metal oxide; and
performing a heat treatment on the lithium transition metal oxide impregnated with the moisture,
wherein a lithium by-product present on a surface of the lithium transition metal oxide and the moisture react to form a passivation layer, having a rock-salt structure, on the surface of the lithium transition metal oxide.

2. The method of claim 1 , wherein the lithium transition metal oxide is impregnated with 300 ppm to 500 ppm of moisture based on 100 parts by weight of the lithium transition metal oxide.

3. The method of claim 1 , wherein the passivation layer comprises lithium carbonate.

4. The method of claim 1 , wherein the lithium transition metal oxide is represented by Formula 1:
Li 1+a [Ni 1−x−y−w Co x M 1 y M 2 w ] 1−a O 2   [Formula 1]

wherein, in Formula 1,
M 1 comprises at least one of manganese (Mn) or aluminum (Al),
M 2 comprises at least one of barium (Ba), calcium (Ca), zirconium (Zr), titanium (Ti), magnesium (Mg), tantalum (Ta), niobium (Nb), or molybdenum (Mo), and
0≤a≤0.5, 0≤x≤0.4, 0≤y≤0.4, and 0≤w≤0.1.

5. The method of claim 1 , wherein the lithium by-product present on the surface of the lithium transition metal oxide comprises at least one of Li 2 O, LiOH, or Li 2 CO 3 .

6. The method of claim 1 , wherein the heat treatment is performed in a temperature range of 500° C. to 900° C. for 3 hours to 15 hours.

7. The method of claim 1 , wherein the passivation layer is changed from a layered structure to the rock salt structure by the heat treatment.

8. A positive electrode active material comprising:
a lithium transition metal oxide containing nickel in an amount of 60 mol % or more based on a total number of moles of metals excluding lithium; and
a passivation layer which is disposed on a surface of the lithium transition metal oxide, has a rock salt structure, and includes lithium carbonate,
wherein the moisture content of the positive electrode active material is below 250 ppm based on 100 parts by weight of the lithium transition metal oxide.

9. The positive electrode active material of claim 8 , wherein the passivation layer has a thickness of 5 nm to 30 nm.

10. The positive electrode active material of claim 8 , wherein the passivation layer is formed by reacting a lithium by-product present on the surface of the lithium transition metal oxide and moisture impregnated in the surface of the lithium transition metal oxide.

11. A positive electrode for a lithium secondary battery, the positive electrode comprising the positive electrode active material of claim 8 .

12. A lithium secondary battery comprising the positive electrode of claim 11 .

Assignees

• Lg Energy Solution Ltd

Inventors

• Han Jung Min
• Han Gi Beom
• Lee Sang Wook
• Kim Hak Yoon
• Baek So Ra
• Jung Wang Mo

Classifications

• H01M2004/028

  Positive electrodes · CPC title

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title

• H01M10/0525

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

• H01M4/505

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