Pitch-based ultrafine carbon fibers, method for producing same, non-aqueous electrolyte secondary battery negative electrode using said pitch-based ultrafine carbon fibers, and non-aqueous electrolyte secondary battery having said non-aqueous electrolyte secondary battery negative electrode

Patent metadata

Field	Value
Publication number	US-2018282909-A1
Application number	US-201615764407-A
Country	US
Kind code	A1
Filing date	Sep 28, 2016
Priority date	Sep 30, 2015
Publication date	Oct 4, 2018
Grant date	—

Abstract

The present invention provides pitch-based ultrafine carbon fibers that have an average fiber diameter of at least 100 nm and less than 700 nm, and an average fiber length of 10 μm or more, wherein C—O bonds>C═O bonds in terms of the abundance ratio (molar ratio) of C—O bonds and C═O bonds derived from the O1s orbital as measured by X-ray photoelectron spectroscopy.

First claim

1 . A pitch-based ultrafine carbon fiber having an average fiber diameter of 100 nm or more and less than 700 nm, and an average fiber length of 10 μm or more, and
satisfying the relationship of C—O bonds>C═O bonds in terms of an abundance ratio (molar ratio) of C—O bonds and C═O bonds derived from an O1s orbital as measured by X-ray photoelectron spectroscopy.

2 . The pitch-based ultrafine carbon fiber according to claim 1 , wherein a distance (d002) between adjacent graphite sheets as measured by wide angle X-ray measurement is 0.335 to 0.340 nm.

3 . The pitch-based ultrafine carbon fiber according to claim 1 , wherein a powder volume resistance in packing at a packing density of 0.8 g/cm3 is 0.1 Ω·cm or less.

4 . A method for manufacturing the pitch-based ultrafine carbon fiber according to claim 1 , the method comprising subjecting the ultrafine carbon fiber to an air oxidation treatment.

5 . The method for manufacturing the pitch-based ultrafine carbon fiber according to claim 4 , wherein the air oxidation treatment is a heat treatment performed in an air atmosphere at 600° C. or higher for 5 to 150 minutes.

6 . A negative electrode for a nonaqueous electrolyte secondary battery comprising the pitch-based ultrafine carbon fiber according to claim 1 .

7 . A nonaqueous electrolyte secondary battery comprising the negative electrode for a nonaqueous electrolyte secondary battery according to claim 6 .

8 . The pitch-based ultrafine carbon fiber according to claim 2 , wherein a powder volume resistance in packing at a packing density of 0.8 g/cm3 is 0.1 Ω·cm or less.

Assignees

• Teijin Ltd

Inventors

• Hirakawa Ryota
• Yachi Kazuki
• Kanematsu Asami

Classifications

• H01M4/133

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

• D06M11/34

  with oxygen, ozone or ozonides · CPC title

• H01M4/625

  Carbon or graphite · CPC title

• D01F9/145 Primary

  from pitch or distillation residues · CPC title

• H01M2004/021

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