Cathode active material for lithium secondary battery, lithium secondary battery and method of manufacturing the same

Patent metadata

Field	Value
Publication number	US-12401035-B2
Application number	US-202117224760-A
Country	US
Kind code	B2
Filing date	Apr 7, 2021
Priority date	Jun 18, 2020
Publication date	Aug 26, 2025
Grant date	Aug 26, 2025

Abstract

A cathode active material for a lithium secondary battery of embodiments of the present invention includes a lithium composite oxide, a first coating part formed on a surface of the lithium composite oxide and containing aluminum, and a second coating part formed on the first coating part and containing boron. Thereby, stability and electrical characteristics of the secondary battery may be improved.

First claim

What is claimed is:

1. A cathode active material for a lithium secondary battery comprising:
a lithium composite oxide;
a first coating part formed on a surface of the lithium composite oxide and containing aluminum, the first coating part having a thickness of 1 to 20 nm;
a second coating part formed on the first coating part and containing boron, the second coating part having a thickness of 3 to 20 nm; and
an intermediate part containing both aluminum and boron between the first coating part and the second coating part,
wherein a doping depth of aluminum in the lithium composite oxide is from 1 to 200 nm,
wherein an amount of aluminum eluted by dissolving the cathode active material in hydrochloric acid for 5% of a time taken to completely dissolve the cathode active material in hydrochloric acid from a surface thereof is 50% by weight or more, based on an amount of aluminum eluted by completely dissolving the cathode active material from the surface thereof,
wherein, in the intermediate part, at least one fragmented ion of LiAlB+, LiAlBOH 4 + , Li 4 AlB + and Li 3 AlB 3 O + is detected upon time-of-flight secondary ion mass spectrometry (TOF-SIMS) analysis,
wherein an aluminum content of the first coating part is 955 to 1,800 ppm based on a total weight of the cathode active material,
wherein a boron content of the second coating part is 800 to 1,200 ppm based on a total weight of the cathode active material.

2. The cathode active material for a lithium secondary battery according to claim 1 , wherein the first coating part has a deviation in an aluminum content of less than 20% in an entire region on the surface thereof.

3. The cathode active material for a lithium secondary battery according to claim 2 , wherein the aluminum content of the first coating part is measured by an intensity of an aluminum peak in an energy-dispersive X-ray spectroscopy (EDS) analysis spectrum, and
the deviation is defined as a percentage of a difference between maximum intensities or minimum intensities based on an average intensity in the aluminum peak.

4. The cathode active material for a lithium secondary battery according to claim 1 , wherein the first coating part contains an excess amount of aluminum compared to boron, and the second coating part contains an excess amount of boron compared to aluminum.

5. The cathode active material for a lithium secondary battery according to claim 1 , wherein the intermediate part has a tendency that a content of aluminum is decreased and a content of boron is increased from the first coating part side to the second coating part side.

6. The cathode active material for a lithium secondary battery according to claim 1 , wherein the first coating part comprises an amorphous aluminum-containing oxide.

7. The cathode active material for a lithium secondary battery according to claim 1 , wherein the first coating part comprises at least one of amorphous Al 2 O 3 , lithium-aluminum oxide, AlOOH, and Al(OH) 3 .

8. The cathode active material for a lithium secondary battery according to claim 1 , wherein the second coating part comprises an amorphous boron-containing oxide.

9. The cathode active material for a lithium secondary battery according to claim 1 , wherein the second coating part comprises at least one of amorphous lithium-boron oxide, LiBO, Li 2 BO 2 , Li 2 B 4 O 7 and Li 4 BO 3 .

10. The cathode active material for a lithium secondary battery according to claim 1 , wherein the lithium composite oxide contains nickel, and a molar fraction of nickel in the lithium composite oxide among the elements except for lithium and oxygen is 0.7 or more.

11. The cathode active material for a lithium secondary battery according to claim 1 , wherein the lithium composite oxide is represented by Formula 1 below:
Li α Ni y M z O 2-β    [Formula 1]

wherein in Formula 1, M is at least one selected from the group consisting of Al, Ti, W, B, F, P, Mg, Mn, Co, V, Cu, Zr, Nb, Mo, Sr, and S, and α, β, y, and z are in a range of 0.7≤α≥1.1, −0.1≤β≤0.5, 0.7≤y≤0.95, and 0.95<y+z≤1.1, respectively.

12. A lithium secondary battery comprising:
an electrode cell which comprises a cathode including the cathode active material for a lithium secondary battery according to claim 1 , an anode, and a separation membrane interposed between the cathode and the anode;
a case configured to house the electrode cell; and
an electrolyte in which the electrode cell is impregnated in the case.

13. The secondary battery according to claim 12 , wherein the first coating part comprises AlF 3 .

Assignees

• Sk Innovation Co Ltd
• Sk On Co Ltd

Inventors

• Choi Ji Hoon
• Kim Sang Bok
• Kim Jik Soo
• Kweon Hee Jun
• Park Sung Soon

Classifications

• H01M10/0525 Primary

  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

• H01M4/0416

  involving impregnation with a solution, dispersion, paste or dry powder (H01M4/0438 takes precedence) · CPC title

• C01P2004/80

  Particles consisting of a mixture of two or more inorganic phases · CPC title