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

Patent metadata

Field	Value
Publication number	US-2022384792-A1
Application number	US-202217828534-A
Country	US
Kind code	A1
Filing date	May 31, 2022
Priority date	May 31, 2021
Publication date	Dec 1, 2022
Grant date	—

Abstract

A cathode active material for a lithium secondary battery includes a core portion comprising a lithium metal oxide particle, and a coating layer at least partially covering a surface of the core portion and including a lithium boron composite oxide. The lithium boron composite oxide is included in an amount from 100 ppm to 1,500 ppm based on a total weight of the cathode active material. A lithium secondary battery having improved structural stability and electrical property is provided using the cathode active material.

First claim

What is claimed is:

1 . A cathode active material for a lithium secondary battery, comprising:
a core portion comprising a lithium metal oxide particle represented by Chemical Formula 1; and a coating layer at least partially covering a surface of the core portion and including a lithium boron composite oxide, wherein the lithium boron composite oxide is included in an amount from 100 ppm to 1,500 ppm based on a total weight of the cathode active material:
Li x Ni a M1 b O 2   [Chemical Formula 1]

wherein, in Chemical Formula 1, M1 is at least one element selected from the group consisting of Co, Mn, Ti, Zr, Al, Mg and Cr, 0.8<x<1.5, 0.7≤a≤0.96, and 0.98≤a+b≤1.02.

2 . The cathode active material for a lithium secondary battery of claim 1 , wherein the coating layer covers 70% or more of a total surface area of the core portion.

3 . The cathode active material for a lithium secondary battery of claim 1 , wherein the coating layer covers 90% or more of a total surface area of the core portion.

4 . The cathode active material for a lithium secondary battery of claim 1 , wherein the lithium metal oxide particle has a layered structure.

5 . The cathode active material for a lithium secondary battery of claim 1 , wherein the lithium boron composite oxide comprises at least one amorphous compound selected from LiBO 2 , Li 2 BO 2 , Li 2 B 4 O 7 , Li 2 B 8 O 13 and Li 3 BO 3 .

6 . The cathode active material for a lithium secondary battery of claim 1 , wherein the coating layer further comprises aluminum.

7 . The cathode active material for a lithium secondary battery of claim 1 , wherein the lithium metal oxide particle comprises a compound represented by Chemical Formula 2:
Li y Ni c Co d Mn e M2 f O 2   [Chemical Formula 2]
wherein, in Chemical Formula 2, M2 is at least one element selected from the group consisting of Ti, Zr, Al, Mg and Cr, 0.8<y<1.5, 0.70≤c≤0.96, 0.02≤d≤0.20, 0.02≤e≤0.20, 0≤f≤0.05, and 0.98≤c+d+e≤1.02.

8 . The cathode active material for a lithium secondary battery of claim 7 , wherein M2 in Chemical Formula 2 is Al, or an alloy of Al and at least one of Ti, Zr, Mg, and Cr.

9 . A lithium secondary battery, comprising:
a cathode comprising the cathode active material for a lithium secondary battery of claim 1 ; and an anode facing the cathode.

10 . A method of preparing a cathode active material for a lithium secondary battery, comprising:
preparing a core portion comprising a lithium metal oxide particle represented by Chemical Formula 1; mixing the core portion and a boron oxide to form a mixture; and heat-treating the mixture to form a coating layer containing a lithium boron composite oxide on a surface of the core portion, wherein the lithium metal oxide particle prepared as the core portion contains a lithium compound in a range from 100 ppm to 2,000 ppm on a surface of the lithium metal oxide particle based on a total weight of the lithium metal oxide particle:
Li x Ni a M1 b O 2   [Chemical Formula 1]

wherein, in Chemical Formula 1, M1 is at least one element selected from the group consisting of Co, Mn, Ti, Zr, Al, Mg and Cr, 0.8<x<1.5, 0.7≤a≤0.96, and 0.98≤a+b≤1.02.

11 . The method of claim 10 , wherein the heat-treating is performed at a temperature in a range from 250° C. to 500° C.

12 . The method of claim 10 , wherein the mixing the core portion and the boron oxide is performed by a mechanical milling.

13 . The method of claim 10 , wherein the coating layer covers 70% or more of a total surface area of the core portion.

14 . The method of claim 10 , wherein the boron oxide is used in an amount from 100 ppm to 1,500 ppm based on a total weight of the lithium metal oxide particle.

15 . The method of claim 10 , wherein the boron oxide has a volumetric average particle diameter in a range from 10 nm to 500 nm.

16 . The method of claim 10 , wherein an aluminum compound is further added in the formation of the mixture.

17 . The method according to claim 10 , wherein a content of the lithium compound on a surface of the cathode active material for a lithium secondary battery is 50% or less of a content of the lithium compound on a surface of the lithium metal oxide particle before the formation of the coating layer.

18 . The method according to claim 10 , wherein the lithium metal oxide particle is represented by Chemical Formula 2:
Li y Ni c Co d Mn e M2 f O 2   [Chemical Formula 2]
wherein, in Chemical Formula 2, M2 is at least one element selected from the group consisting of Ti, Zr, Al, Mg and Cr, 0.8<y<1.5, 0.70≤c≤0.96, 0.02≤d≤0.20, 0.02≤e≤0.20, 0≤f≤0.05, and 0.98≤c+d+e≤1.02.

Assignees

• Sk On Co Ltd

Inventors

• Cho Yong Hyun
• Do Ji Yae
• Lee Yoon Ji
• Kang Min Suk

Classifications

• Y02E60/10

  Energy storage using batteries · CPC title

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title

• H01M4/366 Primary

  as layered products · CPC title

• H01M4/0471

  involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis · 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