Electrode for a lithium battery and lithium battery

Patent metadata

Field	Value
Publication number	US-9337491-B2
Application number	US-201213397344-A
Country	US
Kind code	B2
Filing date	Feb 15, 2012
Priority date	Feb 16, 2011
Publication date	May 10, 2016
Grant date	May 10, 2016

Abstract

An electrode for a lithium battery, which electrode includes an electrode active material which can charge and discharge lithium ions (A), a carbonaceous conductive additive (B) and a binder (C). The carbonaceous conductive additive contains carbon fiber, the carbon fiber including a mixture of two kinds of carbon fibers having different diameter distributions on a number basis; and the fiber diameter distribution of the carbon fiber in the electrode has one or more maximum values at 5-40 nm and at 50-300 nm, respectively. Also disclosed is a lithium battery using the electrode. The electrode enables production of a lithium battery having a reduced discharge capacity decline.

First claim

What is claimed is:

1. An electrode for a lithium battery, which electrode comprises an electrode active material which can charge and discharge lithium ions (A), a carbonaceous conductive additive (B) and a binder (C), wherein the carbonaceous conductive additive contains carbon fiber, said carbon fiber comprising a mixture of two kinds of carbon fibers having different diameter distributions on a number basis; and the fiber diameter distribution of the carbon fiber in the electrode has one or more maximum values at 5-40 nm and at 50-300 nm, respectively,
wherein the two kinds of carbon fibers comprise a carbon fiber (B1), wherein filaments of the carbon fiber (B1) having a fiber diameter falling within a range of 50 to 300 nm account for 90% or more in the fiber diameter distribution on a number basis, and a carbon fiber (B2), wherein filaments of the carbon fiber (B2) having a fiber diameter falling within a range of 5 to 40 nm account for 90% or more in the fiber diameter distribution on a number basis,
wherein the carbon fiber (B2) has a tubular structure, and
wherein the carbon fiber (B2) has an average aspect ratio of 160 or higher.

2. The electrode for a lithium battery as claimed in claim 1 , wherein a content of the electrode active material (A) is 85 mass % or more and 95 mass % or less, a content of the carbonaceous conductive additive (B) is 2 mass % or more and 10 mass % or less, and the binder content (C) is 3 mass % or more and 5 mass % or less, each based on the mass of the electrode.

3. The electrode for a lithium battery as claimed in claim 1 , wherein the electrode active material (A) is an electrode active material for a positive electrode and comprises a lithium-containing metal oxide which can charge and discharge lithium ions.

4. The electrode for a lithium battery as claimed in claim 1 , wherein the electrode active material (A) is an electrode active material for a negative electrode and comprises a material which can charge and discharge lithium ions selected from the group consisting of a carbon material; either of Si or Sn, or an alloy thereof; and oxides containing at least one of a carbon material, Si and Sn.

5. The electrode for a lithium battery as claimed in claim 1 , wherein a blending ratio (B2)/{(B1)+(B2)} of the carbon fiber (B2) to the sum of the carbon fiber (B1) and the carbon fiber (B2) is 5 mass % or more and 20 mass % or less.

6. The electrode for a lithium battery as claimed in claim 1 , wherein the carbonaceous conductive additive comprises the two kinds of carbon fibers (B1) and (B2) having different fiber diameter distributions on a number basis and carbon black (B3).

7. The electrode for a lithium battery as claimed in claim 6 , wherein a blending ratio {(B1)+(B2)}/{(B1)+(B2)+(B3)} of the two kinds of carbon fibers (B1) and (B2) and carbon black (B3) present in the electrode is 20 mass % or more and 50 mass % or less.

8. A lithium battery comprising the electrode for a lithium battery claimed in claim 1 as a constituent element.

Assignees

• Yamamoto Ryuji
• Yamada Yuusuke
• Nakamura Takeshi
• Showa Denko Kk

Inventors

• Yamamoto Ryuji
• Yamada Yuusuke
• Nakamura Takeshi

Classifications

• Y02E60/122

  Cross-Sectional Technologies · mapped topic

• H01M4/623

  fluorinated polymers · CPC title

• H01M4/625 Primary

  Carbon or graphite · CPC title

• H01M10/052

  Li-accumulators · CPC title

• H01M4/139

  Processes of manufacture · CPC title