Negative electrode for secondary battery, and secondary battery including same

Patent metadata

Field	Value
Publication number	US-2022255059-A1
Application number	US-202117616356-A
Country	US
Kind code	A1
Filing date	Jan 25, 2021
Priority date	Apr 3, 2020
Publication date	Aug 11, 2022
Grant date	—

Abstract

The technology relates to a negative electrode for a secondary battery, and a secondary battery including same. The negative electrode comprises a composite material layer having a double-layer structure, but includes silicon oxide and carbon nanotubes in only one layer, such that it is possible to increase the capacity of a battery while preventing structural deterioration of the negative electrode due to changes in electrode volume during charging and discharging.

First claim

What is claimed is:

1 . A negative electrode for a secondary battery, comprising:
a current collector; and a mixture layer formed on one or both surfaces of the current collector, wherein the mixture layer has a two-layer structure in which a first mixture layer and a second mixture layer are stacked, wherein the first mixture layer includes a first carbon material and a silicon oxide as a first active materials in a weight ratio of 90 to 99:1 to 10 and a first needle type carbon-based conductive material as a first conductive material, and wherein the second mixture layer includes a second carbon material as a second active material and a second sphere type carbon-based conductive material as a second conductive material.

2 . The negative electrode of claim 1 , wherein the first mixture layer is disposed directly on the current collector, and
wherein the second mixture layer is disposed on a surface of the first mixture layer on which the current collector is not disposed.

3 . The negative electrode of claim 1 , wherein the second mixture layer is disposed directly on the current collector, and
wherein the first mixture layer is disposed on a surface of the second mixture layer on which the current collector is not disposed.

4 . The negative electrode of claim 1 , wherein the first conductive material includes the needle type carbon-based conductive material and a first sphere type carbon-based conductive material in a weight ratio of 0.01 to 1:0.5 to 5.

5 . The negative electrode of claim 1 , wherein the first mixture layer and the second mixture layer include first and second binders, respectively, and
wherein a weight ratio (B1:B2) of the first binder content (B1) to the second binder content (B2) is in a range of 1.0 to 3.6:1.

6 . The negative electrode of claim 5 , wherein the first binder includes 1 to 10 parts by weight based on a total weight of the first mixture layer.

7 . The negative electrode of claim 1 , wherein the first mixture layer includes:
90 to 100 parts by weight of the first carbon material and 1 to 10 parts by weight of silicon oxide as the first active materials; 0.01 to 1 parts by weight of the first needle type carbon-based conductive material and 0.5 to 5 parts by weight of a first sphere type carbon-based conductive material as conductive materials; and 1 to 10 parts by weight of a first binder.

8 . The negative electrode of claim 1 , wherein the second mixture layer includes:
90 to 100 parts by weight of the second carbon material as the second active material; 0.5 to 5 parts by weight of the second sphere type carbon-based conductive material as the second conductive material; and 1 to 10 parts by weight of a second binder.

9 . The negative electrode of claim 1 , wherein the second sphere type carbon-based conductive material is carbon black, and
wherein the first needle type carbon-based conductive material is a carbon nanotube (CNT), a vapor-grown carbon fiber (VGCF), a carbon nanofiber (CNF), or a mixture of two or more thereof.

10 . The negative electrode of claim 1 ,
wherein a ratio (D1:D2) of an average thickness (D1) of the first mixture layer to an average thickness of the second mixture layer (D2) is in a range of a thickness ratio of 0.1 to 0.9:1.

11 . A secondary battery comprising:
a negative electrode for a secondary battery according to claim 1 ; a positive electrode containing lithium-containing oxide as an active material; and a separator interposed between the negative electrode and the positive electrode.

12 . The secondary battery of claim 11 , wherein the lithium-containing oxide has a structure represented by one of following chemical formulas:
Li x (Ni a Co b Mn c )O 2   [Chemical formula 1]
where 0.5<x<1.3, 0.5<a<1, 0<b<0.25, 0<c<0.25, a+b+c=1, and
Li x (Ni a Co b Mn c Al d )O 2   [Chemical formula 2]

where 0.5<x<1.3, 0.6<a<1, 0<b<0.2, 0<c<0.1, 0<d<0.1, a+b+c+d=1.

Assignees

• Lg Energy Solution Ltd

Inventors

• Sung Ki Won
• Lee Eun Ju
• Kim Ju Ri

Classifications

• H01M2004/027

  Negative electrodes · CPC title

• H01M2004/021

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

• H01M4/366

  as layered products · CPC title

• Y02E60/10

  Energy storage using batteries · CPC title

• H01M4/622

  being polymers · CPC title