Surface-treated graphene, surface-treated graphene/organic solvent dispersion liquid, surface-treated graphene/electrode active material composite particles and electrode paste

Patent metadata

Field	Value
Publication number	US-10714754-B2
Application number	US-201716077627-A
Country	US
Kind code	B2
Filing date	Feb 20, 2017
Priority date	Mar 9, 2016
Publication date	Jul 14, 2020
Grant date	Jul 14, 2020

Abstract

The purpose of the present invention is to provide a graphene which has high dispersibility, high electrical conductivity and oxidation resistance namely a graphene which has high electrochemical stability. In order to achieve the above-described purpose, a surface-treated graphene according to the present invention is obtained by having a compound represented by general formula (1) or a neutralized salt thereof adhere to a graphene. In general formula (1), A represents a benzene-based aromatic group with a condensation number of 1-4, which has no phenolic hydroxy group; R 1 represents a direct bond, a divalent hydrocarbon group having 1-12 carbon atoms, or a divalent organic group having 1-12 carbon atoms, which has a structure selected from the group consisting of an ether bond, an ester bond, an alcohol structure and a carbonyl structure; each of R 2 and R 3 independently represents a hydrogen atom, a hydrocarbon group having 1-12 carbon atoms, or an organic group having 1-12 carbon atoms, which has a structure selected from the group consisting of an ether bond, an ester bond, an alcohol structure and a carbonyl structure; and n represents an integer of 1-6.

First claim

The invention claimed is:

1. A surface-treated graphene, comprising a graphene and a compound represented by the following general formula (1) or a neutralized salt thereof attached to the graphene,
wherein the surface-treated graphene has an element ratio of oxygen to carbon (O/C ratio) of 0.05 or more and 0.40 or less as measured by X-ray photoelectron spectroscopy, and
wherein the surface-treated graphene has a specific surface area as measured by a BET measurement method of 80 m 2 /g or more and 250 m 2 /g or less:

wherein
A represents a phenolic hydroxy group-free benzene-based aromatic group having a condensation number of 1 to 4,
R 1 represents a direct bond, a divalent hydrocarbon group having 1 to 12 carbon atoms, or a divalent organic group having 1 to 12 carbon atoms and having a structure selected from the group consisting of an ether bond, an ester bond, an alcohol structure, and a carbonyl structure,
R 2 and R 3 each independently represent a hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms, or an organic group having 1 to 12 carbon atoms and having a structure selected from the group consisting of an ether bond, an ester bond, an alcohol structure, and a carbonyl structure, and
n represents an integer of 1 to 6.

2. The surface-treated graphene according to claim 1 , wherein 3% by mass or more and 50% by mass or less, relative to the graphene, of the compound represented by the general formula (1) or a neutralized salt thereof is attached to the graphene.

3. The surface-treated graphene according to claim 1 , having an element ratio of nitrogen to carbon (N/C ratio) of 0.005 or more and 0.020 or less as measured by X-ray photoelectron spectroscopy.

4. The surface-treated graphene according to claim 1 , wherein in the general formula (1), R 1 is an alkylene group having 1 to 12 carbon atoms, an alkenoxyalkylene group having 2 to 12 carbon atoms, or a direct bond.

5. The surface-treated graphene according to claim 1 , wherein in the general formula (1), R 2 and R 3 are each a hydrogen atom, a phenyl group, an alkyl group having 1 to 12 carbon atoms, or an alkoxyalkyl group having 2 to 12 carbon atoms.

6. The surface-treated graphene according to claim 1 , wherein the compound represented by the general formula (1) is a compound selected from the group consisting of compounds represented by the following formulae (2) to (5):

7. A surface-treated graphene/organic solvent dispersion liquid, comprising the surface-treated graphene according to claim 1 dispersed in an organic solvent.

8. The surface-treated graphene/organic solvent dispersion liquid according to claim 7 , having a solid content of 0.3% by mass or more and 40% by mass or less.

9. Surface-treated graphene/electrode active material composite particles, comprising a composite of the surface-treated graphene according to claim 1 and electrode active material particles.

10. An electrode paste, comprising the surface-treated graphene according to claim 1 , electrode active material particles, and a binder.

11. A method for producing a surface-treated graphene, comprising mixing graphene oxide with a compound represented by the following general formula (1) or a neutralized salt thereof, and subsequently comprising a reduction step of subjecting the graphene oxide to reduction treatment:

wherein
A represents a phenolic hydroxy group-free benzene-based aromatic group having a condensation number of 1 to 4,
R 1 represents a direct bond, a divalent hydrocarbon group having 1 to 12 carbon atoms, or a divalent organic group having 1 to 12 carbon atoms and having a structure selected from the group consisting of an ether bond, an ester bond, an alcohol structure, and a carbonyl structure,
R 2 and R 3 each independently represent a hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms, or an organic group having 1 to 12 carbon atoms and having a structure selected from the group consisting of an ether bond, an ester bond, an alcohol structure, and a carbonyl structure, and
n represents an integer of 1 to 6.

12. A method for producing a surface-treated graphene/organic solvent dispersion liquid, comprising mixing graphene oxide with a compound represented by the following general formula (1) in a state where the graphene oxide and the compound are dispersed in an aqueous solution, and then subjecting the graphene oxide to reduction treatment, and further comprising an organic solvent substitution step of substituting the solvent with an organic solvent:

wherein
A represents a phenolic hydroxy group-free benzene-based aromatic group having a condensation number of 1 to 4,
R 1 represents a direct bond, a divalent hydrocarbon group having 1 to 12 carbon atoms, or a divalent organic group having 1 to 12 carbon atoms and having a structure selected from the group consisting of an ether bond, an ester bond, an alcohol structure, and a carbonyl structure,
R 2 and R 3 each independently represent a hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms, or an organic group having 1 to 12 carbon atoms and having a structure selected from the group consisting of an ether bond, an ester bond, an alcohol structure, and a carbonyl structure, and
n represents an integer of 1 to 6.

13. The method for producing a surface-treated graphene/organic solvent dispersion liquid according to claim 12 , wherein in the organic solvent substitution step, at any stage before final solvent removal, a strong stirring step is performed, the strong stirring step being a step of stirring a surface-treated graphene/water dispersion liquid and the organic solvent in a mixed state with a high shear mixer at a shear rate of 5,000/sec to 50,000/sec.

Assignees

• Toray Industries

Inventors

• Manabe Koichiro
• Tamaki Eiichiro
• Kawasaki Manabu

Classifications

• H01M4/625 Primary

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• Y02E60/10

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• C01B32/15

  Nano-sized carbon materials · CPC title

• C01B32/182

  Graphene · CPC title