Positive electrode active material comprising lithium-rich lithium manganese-based oxide in which coating layer including lithium-deficient transition metal oxide is formed, and positive electrode for lithium secondary battery comprising the same

Patent metadata

Field	Value
Publication number	US-11258054-B2
Application number	US-201816489922-A
Country	US
Kind code	B2
Filing date	Sep 7, 2018
Priority date	Oct 26, 2017
Publication date	Feb 22, 2022
Grant date	Feb 22, 2022

Abstract

A positive electrode active material contains a lithium-rich lithium manganese-based oxide represented by chemical formula (1),Li1+aNixCoyMnzMvO2−bAb  (1)wherein, 0<a≤0.2, 0<x≤0.4, 0<y≤0.4, 0.5≤z≤0.9, 0≤v≤0.2, a+x+y+z+v=1, and 0≤b≤0.5;M is one or more elements selected from the group consisting of Al, Zr, Zn, Ti, Mg, Ga, In, Ru, Nb, and Sn; andA is one or more elements selected from the group consisting of P, N, F, S and Cl; anda coating layer formed on a surface of the lithium-rich lithium manganese-based oxide,wherein the coating layer contains a lithium-deficient transition metal oxide in a lithium-deficient state having a molar ratio of lithium to transition metal of less than 1 is formed on the surface of the lithium-rich lithium manganese-based oxide, andwherein the content of the coating layer is 1% to 10% by weight based on the total weight of the positive electrode active material.

First claim

The invention claimed is:

1. A positive electrode active material comprising:
a lithium-rich lithium manganese-based oxide, and
a coating layer formed on a surface of the lithium-rich lithium manganese-based oxide,
wherein the lithium-rich lithium manganese-based oxide is represented by the following chemical formula (1),
Li 1+a Ni x Co y Mn z M v O 2-b A b   (1)

wherein, 0<a≤0.2, 0<x≤0.4, 0<y≤0.4, 0.5≤z≤0.9, 0≤v≤0.2, a+x+y+z+v=1, and 0≤b≤0.5;
M is one or more elements selected from the group consisting of Al, Zr, Zn, Ti, Mg, Ga, In, Ru, Nb, and Sn; and
A is one or more elements selected from the group consisting of P, N, F, S and Cl;
wherein the coating layer contains a lithium-deficient transition metal oxide in a lithium-deficient state having a molar ratio of lithium to transition metal of less than 1,
wherein the lithium-deficient transition metal oxide is represented by the following chemical formula (2),
Li a′ MeO 2   (2)

wherein, 0<a′<1,
Me is Ni x′ Co y′ Mn z′ , wherein, 0<x′≤1, 0<y′≤1, 0<z′≤1, and x′+y′+z′=1, and
wherein a content of the coating layer is 1% to 10% by weight based on a total weight of the positive electrode active material.

2. The positive electrode active material according to claim 1 , wherein 0<x′≤0.7, 0<y′≤0.7, and 0.2<z′≤0.6.

3. The positive electrode active material according to claim 1 , wherein a molar ratio of lithium to transition metal in the lithium-deficient transition metal oxide is 0.5 to 0.9.

4. The positive electrode active material according to claim 1 , wherein a thickness of the coating layer is 30 nm to 200 nm.

5. A method for producing the positive electrode active material of claim 1 , comprising:
(i) mixing a lithium-rich transition metal oxide and a lithium-deficient transition metal oxide in a lithium-deficient state having a molar ratio of lithium to transition metal of less than 1 to form a mixture; and
(ii) heat treating the mixture);
wherein the lithium-deficient transition metal oxide is mixed so as to contained in an amount of 1% to 10% by weight based on the total weight of the lithium-rich lithium manganese-based oxide and the lithium-deficient transition metal oxide.

6. The method for producing the positive electrode active material according to claim 5 , wherein the mixing is a dry mixing.

7. The method for producing the positive electrode active material according to claim 5 , wherein the heat treating is performed at 600 to 1100 degrees Celsius.

8. A positive electrode comprising a positive electrode mixture comprising the positive electrode active material according to claim 1 formed on a current collector.

9. A secondary battery comprising the positive electrode according to claim 8 .

Assignees

• Lg Chemical Ltd
• Lg Energy Solution Ltd

Inventors

• Han Gi Beom
• You Min Kyu
• Jo Chi Ho
• Hwang Jintae
• Jung Wang Mo
• Park Sungbin

Classifications

• Y02E60/10

  Energy storage using batteries · CPC title

• H01M4/1391

  of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title

• H01M2004/028

  Positive electrodes · CPC title

• H01M4/366 Primary

  as layered products · CPC title

• H01M4/131 Primary

  Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title