# US 2020/0392002 A1 · Method for shortening fibrous carbon nanohorn aggregate and shortened fibrous carbon nanohorn aggregate

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- Number: US 2020/0392002 A1
- Document ID: US20200392002A1
- Status: Published application
- Kind: A1
- Application number: 16/772,567
- Filed: 2018-11-28
- Published: 2020-12-17
- Earliest claimed: 2017-12-13
- Assignees: NEC Corporation
- Applicants: NEC Corporation
- Inventors: Ryota YUGE
- Web page: https://patentgrep.com/patent/US20200392002A1

## CPC

- C01B 32/18: Nanoonions; Nanoscrolls; Nanohorns; Nanocones; Nanowalls
- H01G 11/06: with one of the electrodes allowing ions to be reversibly doped thereinto, e.g. lithium ion capacitors [LIC]
- B01J 37/14: with gases containing free oxygen
- B01J 37/34: Irradiation by, or application of, electric, magnetic or wave energy, e.g. ultrasonic waves {; Ionic sputtering; Flame or plasma spraying; Particle radiation}
- H01G 11/36: Nanostructures, e.g. nanofibres, nanotubes or fullerenes
- H01G 11/38: Carbon pastes or blends; Binders or additives therein
- H01G 11/50: specially adapted for lithium-ion capacitors, e.g. for lithium-doping or for intercalation
- H01M 4/583: Carbonaceous material, e.g. graphite-intercalation compounds or CFx
- H01M 4/587: for inserting or intercalating light metals
- H01M 4/625: {Carbon or graphite}
- H01M 4/9083: {on carbon or graphite}
- H01M 4/96: Carbon-based electrodes
- C01B 32/152: Fullerenes
- C01B 32/158: Carbon nanotubes
- C01B 32/182: Graphene
- C01B 32/20: Graphite
- C01P 2004/50: Agglomerated particles
- Y02E 60/10: Energy storage using batteries
- Y02E 60/50: Fuel cells
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- H01G: CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE (selection of specified materials as dielectric H01B3/00; capacitors having potential barriers H10D1/62, H10K10/10)
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

Provided is a shortened fibrous carbon nanohorn aggregate (CNB) obtained by shortening a CNB having a length of 1 μm or more and a diameter in the short direction in the range of 30 to 100 nm, by oxidizing, stirring in an acid solution, subjecting to an ultrasonic treatment in a liquid, followed by cutting. The shortened CNB has an end surface on which no tip of the plurality of single-walled carbon nanohorns is disposed toward the longitudinal direction at least one end in the longitudinal direction, and has an excellent dispersibility by shortening the length to less than 1 μm.

## Claims

### Claim 1

A method of shortening a fibrous carbon nanohorn aggregate comprising:
(1) oxidizing a fibrous carbon nanohorn aggregate in which a plurality of single-walled carbon nanohorns are aggregated radially and are connected in a fibrous manner, the fibrous carbon nanohorn aggregate having a length of 1 μm or more and a diameter in the transverse direction in the range of 30 to 100 nm;
(2) agitating the fibrous carbon nanohorn aggregate in an acid solution; and
(3) subjecting the fibrous carbon nanohorn aggregate to ultrasonic treatment in a liquid after the step (2).

### Claim 2 (depends on 1)

The method for shortening a fibrous carbon nanohorn aggregate according to claim 1, wherein the fibrous carbon nanohorn aggregate before the oxidizing of step (1) is performed contains catalyst metal particles therein, and the catalyst metal particles are eluted by stirring in the acid solution of step (2).

### Claim 3 (depends on 1)

The method for shortening a fibrous carbon nanohorn aggregate according to claim 1, wherein the oxidizing of step (1) is a step of heat treatment in an atmosphere gas containing oxygen.

### Claim 4

A fibrous carbon nanohorn aggregate in which a plurality of single-walled carbon nanohorns are assembled radially and connected in a fibrous manner, wherein the fibrous carbon nanohorn aggregate has a diameter in the transverse direction in the range of 30 to 100 nm, and at least one end in the longitudinal direction of the fibrous carbon nanohorn aggregate has an end surface on which no tip of the plurality of single-walled carbon nanohorns is disposed toward the longitudinal direction.

### Claim 5 (depends on 4)

The fibrous carbon nanohorn aggregate according to claim 4, wherein each single-walled carbon nanohorn includes a structure having a diameter of 1 nm to 5 nm, a length of 30 nm to 100 nm, and a tip of the structure having a horn shape.

### Claim 6 (depends on 5)

The fibrous carbon nanohorn aggregate according to claim 5, wherein the single-walled carbon nanohorn includes a graphene sheet structure.

### Claim 7

A fibrous carbon nanohorn aggregate in which a plurality of single-walled carbon nanohorns are assembled radially and are connected in a fibrous manner, wherein the fibrous carbon nanohorn aggregate has a length less than 1 μm, and at least one end of the fibrous carbon nanohorn aggregate in the longitudinal direction has an end face of a two-dimensional radial structure in which the plurality of single-walled carbon nanohorns are not arranged toward the longitudinal direction.

### Claim 8 (depends on 7)

The fibrous carbon nanohorn aggregate according to claim 7, wherein the diameter of the fibrous carbon nanohorn aggregate in the transverse direction is in the range of 30 to 100 nm.

### Claim 9 (depends on 7)

The fibrous carbon nanohorn aggregate according to claim 7, wherein each single-walled carbon nanohorn includes a structure having a diameter of 1 nm to 5 nm, a length of 30 nm to 100 nm, and a tip of the structure having a horn shape.

### Claim 10 (depends on 9)

The fibrous carbon nanohorn aggregate according to claim 9, wherein the single-walled carbon nanohorn includes a graphene sheet structure.

### Claim 11 (depends on 4)

A carbon nanohorn aggregate mixture comprising the fibrous carbon nanohorn aggregate according to claim 4, and at least one type of spherical carbon nanohorn aggregates of a seed-shaped, a bud-shaped, a dahlia-shaped, a petal dahlia-shaped and a petal-shaped one.

### Claim 12 (depends on 4)

A nanocarbon composite comprising the fibrous carbon nanohorn aggregate according to claim 4, and one or more of carbon nanotubes, carbon fibers, graphene, carbon black, fullerene, graphite, and amorphous carbon.

### Claim 13 (depends on 7)

A nanocarbon composite comprising the carbon nanohorn aggregate mixture according to claim 7, and one or more of carbon nanotubes, carbon fibers, graphene, carbon black, fullerenes, graphite, and amorphous carbon.

### Claim 14 (depends on 4)

An electrode paste in which the fibrous carbon nanohorn aggregate according to claim 4 is dispersed in a solvent.

### Claim 15 (depends on 7)

An electrode paste in which the carbon nanohorn aggregate mixture according to claim 7 is dispersed in a solvent.

### Claim 16 (depends on 4)

An electrode film comprising the fibrous carbon nanohorn aggregate according to claim 4.

### Claim 17 (depends on 7)

An electrode film comprising the carbon nanohorn aggregate mixture according to claim 7.

### Claim 18 (depends on 12)

An electrode film comprising the nanocarbon composite according to claim 12.

### Claim 19 (depends on 7)

A carbon nanohorn aggregate mixture comprising the fibrous carbon nanohorn aggregate according to claim 7, and at least one type of spherical carbon nanohorn aggregates of a seed-shaped, a bud-shaped, a dahlia-shaped, a petal dahlia-shaped and a petal-shaped one.

### Claim 20 (depends on 13)

An electrode film comprising the nanocarbon composite according to claim 13