Positive electrode active material and lithium secondary battery comprising the same

Patent metadata

Field	Value
Publication number	US-12456729-B2
Application number	US-202418440988-A
Country	US
Kind code	B2
Filing date	Feb 14, 2024
Priority date	Oct 18, 2019
Publication date	Oct 28, 2025
Grant date	Oct 28, 2025

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:
a bulk particle consisting of a plurality of primary particles that are lithium composite oxides enabling lithium intercalation and deintercalation, wherein a first concentration gradient section in which the concentration of at least one of metal elements constituting the primary particles in the bulk particle increases in a direction (transverse direction) perpendicular to a direction (longitudinal direction) toward a surface region of the bulk particle from a core region of the bulk particle, and a second concentration gradient section in which the concentration of at least one of metal elements constituting the primary particles in the bulk particle decreases in a direction (transverse direction) perpendicular to a direction (longitudinal direction) toward a surface region of the bulk particle from a core region of the bulk particle, are present in the bulk particle, wherein the first concentration gradient and the second concentration gradient section are laterally arranged along a circumferential surface of the bulk particle.

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 bulk 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 bulk particle.

4 . The positive electrode active material of claim 1 , wherein the first concentration gradient section and the second concentration gradient section are not present in a core region of the bulk particle.

5 . The positive electrode active material of claim 1 , wherein a concentration gradient formed by changes in concentration of metal elements constituting the primary particles in the direction toward a surface region of the bulk particle from a core region of the bulk particle is not present in the bulk particle.

6 . The positive electrode active material of claim 1 , wherein the primary particles are the lithium composite oxides comprising nickel, cobalt and manganese other than lithium.

7 . The positive electrode active material of claim 6 , wherein the concentration gradient directions of nickel, cobalt and manganese are different from each other in the first concentration gradient section and/or the second concentration gradient section.

8 . The positive electrode active material of claim 6 , wherein the concentration gradient directions of cobalt and manganese are the same, and the concentration gradient directions of cobalt and manganese are different from that of nickel in the first concentration gradient section and/or the second concentration gradient section.

9 . The positive electrode active material of claim 6 , wherein cobalt in the first concentration gradient section increases to a higher concentration than an average content of cobalt in the bulk particle.

10 . The positive electrode active material of claim 6 , 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 bulk particle.

11 . The positive electrode active material of claim 1 , wherein along the circumferential surface of the bulk 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 of metal elements constituting the primary particles in the bulk particle is maintained are present.

12 . The positive electrode active material of claim 11 , wherein a change rate in concentration of at least one of metal elements constituting the primary particles in the concentration maintenance part is 5 wt % or less per 0.1 μm.

13 . The positive electrode active material of claim 1 , further comprising:
a coating layer which covers at least a part of the surface of the bulk particle, wherein the coating layer contains at least one oxide particle represented by the following formula 2:
Li a A b O c   [Formula 2]

(wherein, 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, Gd and Nd, 0≤a≤6, 0≤b≤4, and 2≤c≤8).

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

15 . A lithium secondary battery, comprising:
a positive electrode formed by coating a current collector with the positive electrode slurry composition of claim 14 .

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

• H01M4/131

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

• Y02E60/10

  Energy storage using batteries · CPC title

• H01M2004/028

  Positive electrodes · CPC title

• H01M2004/021

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

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title