Negative electrode including platy graphite conductive additive for lithium ion battery, and lithium ion battery using the same

Patent metadata

Field	Value
Publication number	US-9620784-B2
Application number	US-201214118338-A
Country	US
Kind code	B2
Filing date	May 15, 2012
Priority date	Jul 14, 2011
Publication date	Apr 11, 2017
Grant date	Apr 11, 2017

Abstract

The purpose of the present invention is to provide a lithium-ion battery that exhibits excellent long-term life properties, does not suffer from rapid capacity degradation, and exhibits excellent charging/discharging characteristics in low-temperature environments. The present invention is directed to a negative electrode for a lithium ion battery, which comprises a negative electrode active material containing a graphite or an amorphous carbon, conductive additives containing a graphite, and a binder; and a lithium ion battery comprising this negative electrode. The negative electrode is characterized in that the negative electrode active material has a spherical or massive shape; the conductive additives have a platy shape; and part of an edge surface of the conductive additives contacts a surface of the negative electrode active material.

First claim

The invention claimed is:

1. A negative electrode for a lithium ion battery, comprising a negative electrode active material containing at least one of a graphite and an amorphous carbon, a conductive additive, and a binder,
wherein the negative electrode active material has a particulate shape;
the conductive additive comprises a platy graphite with a Raman peak intensity ratio I G /I D of 6-12, wherein the I G is an intensity of a peak in a G band in the vicinity of 1,580 cm −1 to 1,600 cm −1 corresponding to the in-plane vibration mode and the I D is an intensity of a peak in a D band in the vicinity of 1360 cm −1 derived from in-plane defects; and
at least a part of an edge surface of the conductive additives contacts a surface of the negative electrode active material; and
wherein D 50s /D 50a , being a ratio of an average particle diameter D 50s of the negative electrode active material to an average particle diameter D 50a of the conductive additive, is 3 or higher and 10 or lower.

2. The negative electrode for a lithium ion battery according to claim 1 , wherein a content of the conductive additive in a negative electrode mixture of the negative electrode for the lithium ion battery is 2.0 mass % or higher and 10 mass % or lower.

3. The negative electrode for a lithium ion battery according to claim 1 , wherein a thickness of the conductive additives is 0.05 μm or larger and 0.5 μm or smaller.

4. The negative electrode for a lithium ion battery according to claim 1 , wherein a specific surface area of the conductive additive is 10 m 2 /g or larger and 40 m 2 /g or smaller.

5. The negative electrode for a lithium ion battery according to claim 4 , wherein the specific surface area of the conductive additive is 20 m 2 /g or larger and 40 m 2 /g or smaller.

6. A lithium ion battery, comprising a positive electrode, a negative electrode and a nonaqueous electrolyte solution, wherein the negative electrode is the negative electrode for the lithium ion battery according to claim 1 .

7. A negative electrode for a lithium ion battery, comprising a negative electrode active material containing at least one of a graphite and an amorphous carbon, a conductive additive, and a binder, wherein the negative electrode active material has a particulate shape;
the conductive additive comprises a platy graphite with a Raman peak intensity ratio I G /I D of 6-12, wherein the I G is an intensity of a peak in a G band in the vicinity of 1,580 cm −1 to 1,600 cm −1 corresponding to the in-plane vibration mode and the I D is an intensity of a peak in a D band in the vicinity of 1360 cm −1 derived from in-plane defects;
at least a part of an edge surface of the conductive additive contacts a surface of the negative electrode active material, and
a content of the conductive additive in a negative electrode mixture of the negative electrode for the lithium ion battery is 2.0 mass % or higher and 10 mass % or lower.

8. The negative electrode for a lithium ion battery according to claim 7 , wherein a specific surface area of the conductive additive is 10 m 2 /g or larger and 40 m 2 /g or smaller.

9. The negative electrode for a lithium ion battery according to claim 8 , wherein the specific surface area of the conductive additive is 20 m 2 /g or larger and 40 m 2 /g or smaller.

10. A lithium ion battery, comprising a positive electrode, a negative electrode and a nonaqueous electrolyte solution, wherein the negative electrode is the negative electrode for the lithium ion battery according to claim 7 .

Assignees

• Azami Takeshi
• Nec Energy Devices Ltd

Inventors

• Azami Takeshi

Classifications

• H01M4/133

  Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx · CPC title

• Y02T10/7011

  Cross-Sectional Technologies · mapped topic

• H01M4/625 Primary

  Carbon or graphite · CPC title

• H01M10/0525

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

• H01M2004/021

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