Positive electrode active material for lithium secondary battery, method for manufacturing same, and lithium secondary battery including same

Patent metadata

Field	Value
Publication number	US-12476245-B2
Application number	US-201917266842-A
Country	US
Kind code	B2
Filing date	Aug 13, 2019
Priority date	Aug 13, 2018
Publication date	Nov 18, 2025
Grant date	Nov 18, 2025

Abstract

A cathode active material for a lithium secondary battery according to embodiments of the present invention includes a lithium metal oxide particle which includes a core part and a shell part and contains nickel (Ni), cobalt (Co) and manganese (Mn). A total Ni content of the lithium metal oxide particle is 70 mol % or more based on a total 100 mol % of Ni, Co and Mn. The shell part includes a depth region in a range of 10 to 100 nm from a surface of the lithium metal oxide particle, and a Co content thereof in the depth region is 1.4 to 6 times a Co content of the core part. Stability of the lithium secondary battery may be improved through surface treatment using high content of Co.

First claim

The invention claimed is:

1 . A cathode active material for a lithium secondary battery comprising:
a lithium metal oxide particle which includes a core part and a shell part and contains nickel (Ni), cobalt (Co) and manganese (Mn), wherein a total Ni content of the lithium metal oxide particle is 75 mol % or more based on a total 100 mol % of Ni, Co and Mn, wherein the core part does not have a concentration gradient of nickel, cobalt and manganese, the shell part includes a depth region in a range of 10 to 100 nm from a surface of the lithium metal oxide particle, a Co content thereof in the depth region is 1.4 to 6 times a Co content of the core part, and a concentration gradient.

2 . The cathode active material for a lithium secondary battery according to claim 1 , wherein a total average composition of the lithium metal oxide particle is represented by Formula 1 below:
LiNi tx Co ty Mn 1-tx-ty-tz M1 tz O 2-a ,  [Formula 1]
wherein in Formula 1, M1 is at least one selected from the group consisting of Na, Mg, Ca, Ti, V, Cr, Cu, Zn, Ge, Sr, Ag, Ba, Zr, Nb, Mo, Al, Ga and B, and, tx, ty, tz and a have a relationship of 0.75≤tx<1, 0<ty≤0.2, 0≤tz≤0.1, 0≤a≤0.5, and 0<1-tx-ty-tz.

3 . The cathode active material for a lithium secondary battery according to claim 2 , wherein in Formula 1, the tx and ty have a relationship of 0.75≤tx≤0.9 and 0.1<ty≤0.2.

4 . The cathode active material for a lithium secondary battery according to claim 2 , wherein the core part has a composition represented by Formula 2 below, and the shell part has a composition represented by Formula 3 below:
LiNi cx Co cy Mn 1-cx-cy-cz M2 cz O 2-b ,  [Formula 2]
wherein in Formula 2, M2 is at least one selected from the group consisting of Na, Mg, Ca, Ti, V, Cr, Cu, Zn, Ge, Sr, Ag, Ba, Zr, Nb, Mo, Al, Ga and B, and, cx, cy, cz and b have a relationship of 0.7≤cx<1, 0<cy≤0.2, 0≤cz≤0.1, 0≤b≤0.5, and 0<1-cx-cy-CZ,
LiNi sx Co sy Mn 1-sx-sy-sz M3 sz O 2-c ,  [Formula 3]

wherein in Formula 3, M3 is at least one selected from the group consisting of Na, Mg, Ca, Ti, V, Cr, Cu, Zn, Ge, Sr, Ag, Ba, Zr, Nb, Mo, Al, Ga and B, and, sx, sy, sz and c have a relationship of 0.6≤sx<0.9, 0<sy≤0.4, 0≤sz≤0.1, 0≤c≤0.5, and 0<1-sx-sy-SZ.

5 . The cathode active material for a lithium secondary battery according to claim 4 , wherein in Formula 2, the cx and cy have a relationship of 0.75≤cx≤0.95 and 0.05≤cy≤0.15.

6 . The cathode active material for a lithium secondary battery according to claim 4 , wherein in Formula 3, the sx and sy have a relationship of 0.6≤sx≤0.9 and 0.08≤sy≤0.3.

7 . The cathode active material for a lithium secondary battery according to claim 1 , wherein metals other than lithium contained in the lithium metal oxide particle are composed of Ni, Co and Mn.

8 . The cathode active material for a lithium secondary battery according to claim 1 , wherein the core part has a uniform composition over an entire area of the core part.

9 . The cathode active material for a lithium secondary battery according to claim 1 , wherein a content of Ni is decreased, while a content of Co is increased from an outermost surface of the core part to an outermost surface of the shell part.

10 . The cathode active material for a lithium secondary battery according to claim 1 , wherein a content of Mn is constant over an entire region of the lithium metal oxide particle.

11 . A lithium secondary battery comprising:
an electrode assembly including a cathode including the cathode active material according to claim 1 , an anode, and a separation membrane disposed between the cathode and the anode; an outer case configured to house the electrode assembly; and an electrolyte in which the electrode assembly is impregnated in the outer case.

Assignees

• Sk Innovation Co Ltd
• Sk On Co Ltd

Inventors

• Noh Mi Jung
• Kim Jik Soo
• Han Kook Hyun

Classifications

• 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

• C01P2006/40

  Electric properties · CPC title

• C01P2004/61

  Micrometer sized, i.e. from 1-100 micrometer · CPC title