Positive electrode active material for rechargeable lithium battery and rechargeable lithium battery including same

Patent metadata

Field	Value
Publication number	US-12597595-B2
Application number	US-201916960791-A
Country	US
Kind code	B2
Filing date	Mar 6, 2019
Priority date	May 17, 2018
Publication date	Apr 7, 2026
Grant date	Apr 7, 2026

Abstract

The present invention relates to a positive electrode active material for a rechargeable lithium battery and a rechargeable lithium battery including same, wherein the positive electrode active material comprises a core and a surface layer formed on the surface of the core, the core comprising a first crystalline structure, the surface layer comprising a first crystalline structure and a second crystalline structure different from the first crystalline structure, the first crystalline structure being present more than the second crystalline structure in the surface layer.

First claim

The invention claimed is:

1 . A positive electrode active material for a rechargeable lithium battery, comprising,
a particle comprising a core and a surface layer formed on the core, the core comprising a first core crystalline structure, the surface layer comprising a first surface crystalline structure and a second surface crystalline structure different from the first surface crystalline structure and the first core crystalline structure, the first surface crystalline structure being present at a higher concentration than the second crystalline structure in the surface layer, wherein a volume ratio of the first surface crystalline structure and the second surface crystalline structure is 9:1 to 7:3 in the surface layer, wherein the surface layer is the outermost layer of the particle, and wherein the first core crystalline structure is a layered structure, and the first surface crystalline structure is a layered structure which is a main phase, and the second surface crystalline structure is a spinel structure, and wherein the surface layer comprises a compound represented by Chemical Formula 1,
Li a Co 1-b X b O 2   [Chemical Formula 1]

wherein, in Chemical Formula 1, 0.90≤a≤1.8, 0≤b≤0.5, and X is selected from Al, Ni, Co, Cr, Fe, Mg, Sr, V, rare-earth elements, or a combination thereof.

2 . The positive electrode active material of claim 1 , wherein
the core comprises a compound represented by Chemical Formula 1 and including the first core crystalline structure:
Li a Co 1-b X b O 2   [Chemical Formula 1]

wherein, in Chemical Formula 1, 0.90≤a≤1.8, 0≤b≤0.5, and X is selected from Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare-earth elements, or a combination thereof.

3 . The positive electrode active material of claim 1 , wherein
the core and the surface layer comprise the same lithiated intercalation compound.

4 . The positive electrode active material of claim 1 , wherein
the surface layer has a thickness of 10 nm to 100 nm.

5 . The positive electrode active material of claim 1 , wherein:
the positive electrode active material is prepared by mixing a core comprising a compound represented by Chemical Formula 1, a lithium source, and a cobalt source to prepare a mixture; heat-treating the mixture to be a heat-treated product; and cooling the heat-treated product at a cooling rate of 4° C./min or less:
Li a Co 1-b X b O 2   [Chemical Formula 1]

wherein, in Chemical Formula 1, 0.90≤a≤1.8, 0≤b≤0.5, and X is selected from Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare-earth elements, or a combination thereof.

6 . The positive electrode active material of claim 5 , wherein the cooling is performed at a cooling rate of 1.0° C./min to 2.5° C./min.

7 . A rechargeable lithium battery, comprising:
a positive electrode comprising the positive electrode active material of claim 1 ; a negative electrode comprising a negative electrode active material; and an electrolyte.

8 . A positive electrode active material for a rechargeable lithium battery, comprising,
a particle comprising a core and a surface layer formed on the core, the core comprising a first core crystalline structure, the surface layer comprising a first surface crystalline structure and a second surface crystalline structure different from the first surface crystalline structure and the first core crystalline structure, the first surface crystalline structure being present at a higher concentration than the second crystalline structure in the surface layer, and the first surface crystalline structure is a layered structure as a main phase, wherein the surface layer comprises a compound represented by Chemical Formula 1
Li a Co 1-b X b O 2   [Chemical Formula 1]

wherein, in Chemical Formula 1, 0.90≤a≤1.8, 0≤b≤0.5, and X is selected from Al, Ni, Co, Cr, Fe, Mg, Sr, V, rare-earth elements, or a combination thereof.

9 . The positive electrode active material for a rechargeable lithium battery of claim 1 , wherein the core further comprises a second core crystalline structure and the second core crystalline structure is a spinel structure.

10 . The positive electrode active material for a rechargeable lithium battery of claim 8 , wherein the core further comprises a second core crystalline structure and the second core crystalline structure is a spinel structure.

Assignees

• Samsung Sdi Co Ltd

Inventors

• Kim Young-Ki
• Lee Soonrewl
• Lee Young-Hun
• Jang Jiyeon
• Choi Ickkyu
• Hong Mingzi
• Hong Soonkie

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

• H01M4/525

  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

• H01M4/364

  as mixtures · CPC title