Negative electrode and secondary battery including the same

Patent metadata

Field	Value
Publication number	US-2024274804-A1
Application number	US-202418643682-A
Country	US
Kind code	A1
Filing date	Apr 23, 2024
Priority date	Dec 1, 2017
Publication date	Aug 15, 2024
Grant date	—

Abstract

A negative electrode including: a current collector; a first negative electrode active material layer positioned on at least one surface of the current collector for a negative electrode and containing a first carbonaceous active material; and a second negative electrode active material layer positioned on a surface of the first negative electrode active material layer and containing a silicon-based active material and carbon nanotubes. A lithium secondary battery including the negative electrode is also disclosed.

First claim

What is claimed is:

1 . A negative electrode comprising:
a current collector; a first negative electrode active material layer positioned on at least one surface of the current collector, wherein the first negative electrode active material layer comprises a first carbonaceous active material; and a second negative electrode active material layer positioned on a surface of the first negative electrode active material layer, wherein the second negative electrode active material layer comprises a silicon-based active material and carbon nanotubes, wherein the carbon nanotubes are positioned in a line contact mode and distributed homogeneously on a surface of the silicon-based active material.

2 . The negative electrode according to claim 1 , wherein the second negative electrode active material layer further comprises a second carbonaceous active material.

3 . The negative electrode according to claim 2 , wherein the carbon nanotubes are positioned in the line contact mode and distributed homogeneously on at least one of a surface of the second carbonaceous active material and the surface of the silicon-based active.

4 . The negative electrode according to claim 2 , wherein the carbon nanotubes are distributed homogeneously throughout the second negative electrode active material layer and are positioned in the line contact mode to form a conductive path directly between respective ends of the carbon nanotubes and at least one of a surface of the second carbonaceous active material and the surface of the silicon-based active material.

5 . The negative electrode according to claim 4 , wherein the conductive path is linear.

6 . The negative electrode according to claim 2 , wherein the carbon nanotubes are positioned in the line contact mode and distributed homogeneously on the surface of the silicon-based active material by applying a slurry comprising a uniform mixture of the second carbonaceous active material, the silicon-based active material, and the carbon nanotubes as the second carbonaceous active material layer.

7 . The negative electrode according to claim 1 , wherein the carbon nanotubes are present in an amount of 0.1 wt % to 2 wt % based on a total weight of the first and second negative electrode active material layers.

8 . The negative electrode according to claim 1 , wherein the carbon nanotubes are present in an amount of 1 part to 20 parts by weight based on 100 parts by weight of the silicon-based active material.

9 . The negative electrode according to claim 1 , wherein the carbon nanotubes have an average diameter of 10 nm to 120 nm and an average length of 0.5 μm to 20 μm.

10 . The negative electrode according to claim 1 , wherein the carbon nanotubes have a specific surface area of 100 m 2 /g to 3,000 m 2 /g.

11 . The negative electrode according to claim 1 , wherein the silicon-based active material is present in an amount of 1 wt % to 30 wt % based on a total weight of the first and second negative electrode active material layers.

12 . The negative electrode according to claim 1 , wherein the first negative electrode active material layer and the second negative electrode active material layer have a thickness ratio of 90:10 to 10:90.

13 . A lithium secondary battery comprising the negative electrode as defined in claim 1 .

14 . The negative electrode according to claim 1 , wherein the silicon-based active material consists of SiO particles.

15 . The negative electrode according to claim 1 , wherein the second negative electrode active material layer consists of a silicon-based active material, a second carbonaceous active material, a binder polymer, and a conductive material comprising carbon nanotubes.

16 . The negative electrode according to claim 1 , wherein the carbon nanotubes have a linear shape.

17 . The negative electrode according to claim 1 , wherein the carbon nanotubes have an aspect ratio of 40 to 6,000.

18 . The negative electrode according to claim 1 , wherein the carbon nanotubes have an average diameter of 20 to 100 nm and an average length in a range of 1 to 10 μm.

19 . The negative electrode according to claim 1 , wherein the linear contact mode excludes spot contact between the carbon nanotubes and the surface of the silicon-based active material.

20 . The negative electrode according to claim 1 , wherein the silicon-based material has an average particle diameter of greater than 1 μm to 5 μm.

Assignees

• Lg Energy Solution Ltd

Inventors

• Kim Hyun-Min
• Kim Min-Kyung
• Seol Jong-Heon
• Sung Ki-Won
• Lee Myung-Ki
• Lee Eun-Ju
• Choi Young-Eun

Classifications

• H01M2004/027

  Negative electrodes · CPC title

• H01M10/0525

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

• H01M4/625

  Carbon or graphite · CPC title

• H01M4/587

  for inserting or intercalating light metals · CPC title

• H01M4/386

  Silicon or alloys based on silicon · CPC title