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

Patent metadata

Field	Value
Publication number	US-2025293238-A1
Application number	US-202519221512-A
Country	US
Kind code	A1
Filing date	May 29, 2025
Priority date	Apr 22, 2021
Publication date	Sep 18, 2025
Grant date	—

Abstract

The cathode active material for a lithium secondary battery according to embodiments of the present invention includes a lithium-transition metal composite oxide particle including a plurality of primary particles, and the lithium-transition metal composite oxide particle includes a lithium-sulfur-containing portion formed between the primary particles. Thereby, it is possible to improve life-span properties and capacity properties by preventing the layer structure deformation of the primary particles and removing residual lithium.

First claim

What is claimed is:

1 . A cathode active material for a lithium secondary battery comprising:
a lithium-transition metal composite oxide particle including a plurality of primary particles, wherein the lithium-transition metal composite oxide particle comprises a lithium-sulfur-containing portion formed between the primary particles, and wherein the average sulfur signal value of the lithium-sulfur-containing portion measured through the EDS is 1.2 to 3.8 times greater than the average sulfur signal value in the primary particles measured through the EDS.

2 . The cathode active material for a lithium secondary battery according to claim 1 , wherein the lithium-sulfur-containing portion has a monoclinic crystal structure.

3 . The cathode active material for a lithium secondary battery according to claim 1 , wherein a sulfur content in the lithium-transition metal composite oxide particle measured through a carbon-sulfur (CS) analyzer is 2,000 to 7,000 ppm based on a total weight of the lithium-transition metal composite oxide particle.

4 . The cathode active material for a lithium secondary battery according to claim 1 , wherein an average sulfur signal value of the lithium-sulfur-containing portion measured through energy dispersive spectroscopy (EDS) is greater than the average sulfur signal value in the primary particles measured through the EDS.

5 . The cathode active material for a lithium secondary battery according to claim 1 , wherein the lithium-sulfur-containing portion is derived from a sulfonyl-based compound represented by Structural Formula 1 below:

(In Structural Formula 1, n is 0≤n<3, R 1 and R 2 are O − , NH 2 , NH 3 + , OH, or a hydrocarbon group having 1 to 3 carbon atoms that can be substituted with a substituent, and the substituent includes a halogen, cyano group, hydroxyl group, phosphoric acid group, carboxyl group or a salt thereof).

6 . The cathode active material for a lithium secondary battery according to claim 5 , wherein the hydrocarbon group included in R 1 and R 2 in Structural Formula 1 is substituted with or connected to at least one selected from the group consisting of a carbon-carbon double bond, —O—, —S—, —CO—, —OCO—, —SO—, —CO—O—, —OCO—O—, —S—CO—, —S—CO—O—, —CO—NH—, —NH—CO—O—, —NR′—,

—S—S— and —SO 2 —, and R′ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

7 . The cathode active material for a lithium secondary battery according to claim 5 , wherein the sulfonyl-based compound includes at least one of compounds of Formulae 1 to 3 below:

8 . The cathode active material for a lithium secondary battery according to claim 1 , wherein the primary particles have a hexagonal close-packed structure.

9 . The cathode active material for a lithium secondary battery according to claim 1 , wherein a content of lithium carbonate (Li 2 CO 3 ) remaining on the surface of the lithium-transition metal composite oxide particle is 2,500 ppm or less based on the total weight of the lithium-transition metal composite oxide particle, and
a content of lithium hydroxide (LiOH) remaining on the surface of the lithium-transition metal composite oxide particle is 2,000 ppm or less based on the total weight of the lithium-transition metal composite oxide particle.

10 . A lithium secondary battery comprising:
a cathode comprising a cathode active material layer including the cathode active material for a lithium secondary battery according to claim 1 ; and an anode disposed to face the cathode.

Assignees

• Sk On Co Ltd

Inventors

• Kim Sang Bok
• Shin Sang Hye
• Park Sang Min
• Lee Tae Kyoung
• Kim Myoung Lae
• Yoon Jeong Bae
• Kim Jik Soo
• 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

• H01M4/60

  of organic compounds · 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