Positive electrode active material and lithium secondary battery comprising the same

Patent metadata

Field	Value
Publication number	US-11942635-B2
Application number	US-202017035672-A
Country	US
Kind code	B2
Filing date	Sep 28, 2020
Priority date	Oct 18, 2019
Publication date	Mar 26, 2024
Grant date	Mar 26, 2024

Abstract

The present invention relates to a positive electrode active material and a lithium secondary battery using a positive electrode containing the positive electrode active material. More particularly, the present invention relates to a positive electrode active material that is able to solve a problem of increased resistance according to an increase in Ni content by forming a charge transport channel in a lithium composite oxide and a lithium secondary battery using a positive electrode containing the positive electrode active material.

First claim

What is claimed is:

1. A positive electrode active material, comprising:
primary particles enabling lithium intercalation and deintercalation;
a secondary particle formed by aggregating the primary particles; and
a coating layer,
wherein the coating layer covers at least a part of an interface between the primary particles, or at least a part of the surface of the secondary particle, or both at least the part of the interface between the primary particles and at least the part of the surface of the secondary particle,
wherein the secondary particle has a first concentration gradient section in which the concentration of at least one selected from nickel, cobalt and manganese in the secondary particle increases, and a second concentration gradient section in which the concentration of at least one selected from nickel, cobalt and manganese in the secondary particle decreases,
wherein the first concentration gradient section and the second concentration gradient section are laterally arranged along the circumferential surface of the secondary particle, and
wherein the concentration of the first concentration gradient section and the concentration of the second concentration gradient section are not due to the coating layer.

2. The positive electrode active material of claim 1 , wherein the first concentration gradient section and the second concentration gradient section are present in a surface region of the secondary particle.

3. The positive electrode active material of claim 1 , wherein the first concentration gradient section and the second concentration gradient section are repeatedly present along the circumferential surface of the secondary particle.

4. The positive electrode active material of claim 1 , wherein the first concentration gradient section is disposed adjacent to the second concentration gradient section in a direction (transverse direction) perpendicular to a direction (longitudinal direction) toward a surface region of the secondary particle from a core region of the secondary particle.

5. The positive electrode active material of claim 1 , wherein cobalt in the first concentration gradient section increases to a higher concentration than an average content of cobalt in the secondary particle.

6. The positive electrode active material of claim 1 , wherein an amount of the cobalt in the second concentration gradient section decreases to be close to an average amount of the cobalt in the secondary particle.

7. The positive electrode active material of claim 1 , wherein along the circumferential surface of the secondary particle, a concentration increase/decrease part having the first concentration gradient section and the second concentration gradient section and a concentration maintenance part in which the concentration of at least one selected from nickel, cobalt and manganese in the secondary particle is maintained are present.

8. The positive electrode active material of claim 7 , wherein a change rate in concentration of at least one selected from nickel, cobalt and manganese in the concentration maintenance part is 5 wt % or less per 0.1 μm.

9. The positive electrode active material of claim 1 ,
wherein the coating layer contains at least one oxide represented by the following formula:
Li a A b O c   [Formula]

(where A is at least one selected from Ni, Mn, Co, Fe, Cu, Nb, Mo, Ti, Al, Cr, Zr, Zn, Na, K, Ca, Mg, Pt, Au, B, P, Eu, Sm, W, Ce, V, Ba, Ta, Sn, Hf, Ce, Gd and Nd, 0≤a≤6, 0≤b≤4, and 2≤c≤8).

10. A positive electrode slurry composition, comprising:
the positive electrode active material of claim 1 , a conductive material and a binder.

11. A lithium secondary battery, comprising:
a positive electrode formed by coating a current collector with the positive electrode slurry composition of claim 10 .

Assignees

• Ecopro Bm Co Ltd

Inventors

• Choi Moon Ho
• Suh Jun Won
• Yun Jin Kyeong
• Lee Jung Han
• Yun Mi Hye
• Choi Seung Woo
• Choe Gwang Seok
• Jang Ye Ri
• Bae Joong Ho

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 Primary

  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

• H01M4/485

  of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy (H01M4/505, H01M4/525 take precedence) · CPC title