Cathode active material for lithium secondary battery and lithium secondary battery including the same

Patent metadata

Field	Value
Publication number	US-2025289735-A1
Application number	US-202519079469-A
Country	US
Kind code	A1
Filing date	Mar 14, 2025
Priority date	Mar 15, 2024
Publication date	Sep 18, 2025
Grant date	—

Abstract

A cathode active material for a lithium secondary battery according to embodiments of the present invention includes lithium-nickel metal oxide particles having an expansion phase ratio of 30 to 40% and a contraction phase ratio of 35 to 45% measured in a voltage region of 3.75 V to 4.15 V by in-situ X-ray diffraction (in-situ XRD), and a content of Ni among metal elements except for lithium of 90 mol % to 99 mol %. A lithium secondary battery including the cathode active material may have improved lifespan characteristics.

First claim

What is claimed is:

1 . A cathode active material for a lithium secondary battery comprising:
lithium-nickel metal oxide particles which comprise 90 mol % to 99 mol % of Ni among metal elements except for lithium, wherein a (113) plane peak of the lithium-nickel metal oxide particles measured through in-situ X-ray diffraction analysis (in-situ XRD) is separated into a main phase peak having the highest peak intensity in a voltage region of 3.75 V to 4.15 V; an expansion phase peak appearing at a first diffraction angle smaller than a main diffraction angle at which the main phase peak appears; and a contraction phase peak appearing at a second diffraction angle larger than the main diffraction angle, and a ratio of an integral area of the expansion phase peak to a sum of integral areas of the main phase peak, the expansion phase peak and the contraction phase peak is 30 to 40%, and a ratio of the integral area of the contraction phase peak to the sum of integral areas is 35 to 45%.

2 . The cathode active material for a lithium secondary battery according to claim 1 , wherein a difference between the main diffraction angle and the first diffraction angle is greater than 0 and 1° or less, and a difference between the main diffraction angle and the second diffraction angle is greater than 0 and 1° or less.

3 . The cathode active material for a lithium secondary battery according to claim 1 , wherein the lithium-nickel metal oxide particles comprise at least one doping element.

4 . The cathode active material for a lithium secondary battery according to claim 1 , wherein the lithium-nickel metal oxide particles are represented by Formula 1 below:
Li x Ni a Co b Mn c M d O 2+y   [Formula 1]
(in Formula 1, M includes at least one of Ti, Zr, Al, Mg, Sr and W, and x, a, b, c, d and y satisfy 0.8<x<1.5, 0.90≤a≤0.99, 0≤b≤0.10, 0≤c≤0.10, 0≤d≤0.05, 0.98≤a+b+c≤1.02, −0.1≤y≤0.1).

5 . The cathode active material for a lithium secondary battery according to claim 4 , wherein in Formula 1 above, a is in a range of 0.94≤a≤0.98.

6 . The cathode active material for a lithium secondary battery according to claim 4 , wherein in Formula 1 above, b is in a range of 0≤b≤0.05.

7 . The cathode active material for a lithium secondary battery according to claim 4 , wherein in Formula 1 above, c is in a range of 0≤c≤0.05.

8 . The cathode active material for a lithium secondary battery according to claim 4 , wherein in Formula 1 above, c is b or less (c≤b).

9 . The cathode active material for a lithium secondary battery according to claim 4 , wherein in Formula 1 above, M includes two or more of Ti, Zr, Al, Mg, Sr and W.

10 . The cathode active material for a lithium secondary battery according to claim 1 , wherein a variation in a d value of the lithium-nickel metal oxide particles measured in a voltage region of greater than 4.15 V and 4.18 V or less through the in-situ X-ray diffraction analysis (in-situ XRD) is 0.1 to 0.15.

11 . The cathode active material for a lithium secondary battery according to claim 1 , wherein a variation in an a-axis lattice constant among the lattice constants of the lithium-nickel metal oxide particles measured through the in-situ X-ray diffraction analysis (in-situ XRD) is 0.05 to 0.08 Å, and a variation in a c-axis lattice constant is 0.8 to 1.2 Å.

12 . A lithium secondary battery comprising:
a cathode which comprises the cathode active material for a lithium secondary battery of claim 1 ; and an anode disposed to face the cathode.

Assignees

• Sk On Co Ltd

Inventors

• Kweon Hee Jun
• Yoon Jeong Bae
• Kim Sang Bok
• Choi Ji Hoon

Classifications

• H01M2004/028

  Positive electrodes · CPC title

• H01M10/0525

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

• H01M4/505

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

• H01M4/525 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

• Y02E60/10

  Energy storage using batteries · CPC title