Slurry including carbon black, electrode paste, method for producing electrode, and method for producing secondary battery

Patent metadata

Field	Value
Publication number	US-11637290-B2
Application number	US-202017605814-A
Country	US
Kind code	B2
Filing date	Apr 17, 2020
Priority date	Apr 26, 2019
Publication date	Apr 25, 2023
Grant date	Apr 25, 2023

Abstract

A slurry including at least a carbon black and a dispersion medium, wherein a concentration of the carbon black in the slurry is 5% by mass or more and 25% by mass or less, and wherein in a volume-based frequency distribution of particle size of the carbon black measured by a laser diffraction/scattering method, provided that a volume concentration of carbon black with a particle size of 0.6 μm or more is x (%), a volume concentration of carbon black with a particle size of 0.3 μm or more and less than 0.6 μm is y (%), and a volume concentration of carbon black having a particle size of less than 0.3 μm is 100−(x+y) (%), the slurry satisfies 10≤x≤70, 30≤y≤90, and 0≤100−(x+y)≤30.

First claim

The invention claimed is:

1. A slurry comprising at least a carbon black and a dispersion medium,
wherein a concentration of the carbon black in the slurry is 5% by mass or more and 25% by mass or less, and
wherein in a volume-based frequency distribution of particle size of the carbon black measured by a laser diffraction/scattering method, provided that a volume concentration of carbon black with a particle size of 0.6 μm or more is x (%), a volume concentration of carbon black with a particle size of 0.3 μm or more and less than 0.6 μm is y (%), and a volume concentration of carbon black having a particle size of less than 0.3 μm is 100−(x+y) (%), the slurry satisfies 10≤x≤70, 30≤y≤90, and 0≤100−(x+y)≤30.

2. The slurry according to claim 1 , wherein a cumulative 50% particle size (D50) in the volume-based cumulative distribution of particle size of the carbon black measured by the laser diffraction/scattering method is 0.40 to 0.85 μm.

3. The slurry according to claim 1 , wherein a cumulative 90% particle size (D90) in the volume-based cumulative distribution of particle size of the carbon black measured by the laser diffraction/scattering method is 1.0 to 30.0 μm.

4. The slurry according to claim 1 , comprising N-methyl-2-pyrrolidone as a dispersion medium.

5. The slurry according to claim 1 , comprising a dispersant.

6. The slurry according to claim 5 , wherein a content of the dispersant in the slurry is 5 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the carbon black.

7. The slurry according to claim 5 , comprising a nonionic dispersant as the dispersant.

8. The slurry according to claim 5 , comprising polyvinyl alcohol as the dispersant.

9. The slurry according to claim 8 , wherein a degree of saponification of the polyvinyl alcohol is 86 to 97 mol %.

10. The slurry according to claim 1 , satisfying 30≤x≤60,30≤y≤60, and 10≤100−(x+y)≤30.

11. An electrode paste, comprising the slurry according to claim 1 , an electrode active material, and a binder.

12. A method for producing an electrode, comprising applying the electrode paste according to claim 11 to a current collector.

13. A method for producing a secondary battery comprising a positive electrode, a negative electrode, and an electrolyte, the method comprising producing one or both of the positive electrode and the negative electrode by carrying out the method for producing an electrode according to claim 12 .

Assignees

• Denka Company Ltd

Inventors

• Yoda Akira
• Nagai Tatsuya
• Ito Tetsuya

Classifications

• H01M4/623

  fluorinated polymers · CPC title

• H01M4/625 Primary

  Carbon or graphite · CPC title

• H01M4/1391

  of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title

• C01P2006/22

  Rheological behaviour as dispersion, e.g. viscosity, sedimentation stability · CPC title

• C01P2004/62

  Submicrometer sized, i.e. from 0.1-1 micrometer · CPC title