Metal-carbon composites and methods for their production

Patent metadata

Field	Value
Publication number	US-11325348-B2
Application number	US-201815985785-A
Country	US
Kind code	B2
Filing date	May 22, 2018
Priority date	May 23, 2017
Publication date	May 10, 2022
Grant date	May 10, 2022

Abstract

A method for producing a carbon nanotube-metal composite in which carbon nanotubes are layered on a metal substrate, the method comprising: (i) depositing a liquid, in which carbon nanotubes are suspended, onto said metal substrate; (ii) during or after step (i), subjecting said liquid to a shearing force sufficient to spatially confine the liquid to induce at least partial alignment of said carbon nanotubes on said metal substrate; and (iii) removing said liquid to produce said carbon nanotube-metal composite; wherein, after step (iii), the lengthwise dimensions of said carbon nanotubes are adhered to and oriented parallel with said metal surface, and said carbon nanotubes are at least partially aligned with each other. In some embodiments, the liquid is deposited in the form of droplets, and the droplets are subjected to a shearing force to cause them to elongate, which induces at least partial alignment of the carbon nanotubes.

First claim

What is claimed is:

1. A method for producing a carbon nanotube-metal composite in which carbon nanotubes are layered on a metal substrate, the method comprising:
(i) spreading a liquid in which carbon nanotubes are suspended over said metal substrate;
(ii) during or after step (i), subjecting said liquid, while spread over said metal substrate, to a shearing force sufficient to spatially confine the liquid suspension to induce at least partial alignment of said carbon nanotubes;
(iii) removal of said liquid to produce said carbon nanotube-metal composite; wherein, after step (iii), the lengthwise dimensions of said carbon nanotubes are adhered to and oriented parallel with said metal surface, and said carbon nanotubes are at least partially aligned with each other;
(iv) coating a layer of metal onto the at least partially aligned carbon nanotubes to result in said carbon nanotubes sandwiched between said metal substrate and an overlayer of said metal; and
(v) coating said overlayer of metal with a second coating of carbon nanotubes according to steps (i)-(iii).

2. The method of claim 1 , wherein the method comprises:
(i) producing droplets of a liquid in which carbon nanotubes are suspended;
(ii) depositing said droplets onto said metal substrate;
(iii) during or after step (ii), subjecting said droplets to a shearing force sufficient to elongate said droplets and induce at least partial alignment of said carbon nanotubes on said metal substrate; and
(iv) removal of said liquid to produce said carbon nanotube-metal composite;
wherein, after step (iv), the lengthwise dimensions of said carbon nanotubes are adhered to and oriented parallel with said metal surface, and said carbon nanotubes are at least partially aligned with each other.

3. The method of claim 2 , wherein said shearing force is provided by a sonospray method in which ultrasound generates said droplets, and a gaseous jet carries the droplets to the metal substrate with sufficient force to elongate said droplets, and wherein said metal substrate is oriented at a substantially oblique angle to the direction of the gaseous jet.

4. The method of claim 3 , wherein said gaseous jet carrying said droplets is moved across the surface of the metal substrate, and/or said metal substrate is moved while said gaseous jet carries said droplets, in order to deposit said carbon nanotubes across a desired surface area of said metal substrate.

5. The method of claim 1 , wherein said shearing force is provided by an air knife method in which gaseous flow impinges on said liquid suspension at an oblique angle to spatially confine said liquid suspension when said liquid suspension is spread over as a continuous film over said area of said metal substrate.

6. The method of claim 2 , wherein said shearing force is provided by an electrospraying method in which a voltage drop is established between said droplets and said metal substrate when said droplets are not in contact with said metal substrate, wherein said voltage drop is of sufficient magnitude to render the droplets electrically charged, and wherein the charged droplets are attracted to and impinge on said metal substrate, which bears a charge opposite the charge on the droplets, while said metal substrate is moving at a speed that induces elongation of said droplets when said droplets impinge on said metal substrate.

7. The method of claim 1 , wherein said overlayer of metal has a thickness of 10-5000 nm.

8. The method of claim 1 , further comprising coating said overlayer of metal with a second coating of carbon nanotubes according to steps (i)-(iii) and coating said second coating of carbon nanotubes with a second overlayer of metal, to result in a carbon nanotube-metal composite possessing a multilayer structure by having at least two separate layers of carbon nanotubes, with each layer of carbon nanotubes sandwiched by layers of metal, wherein the bottom-most layer of metal is said metal substrate.

9. The method of claim 8 , wherein the multilayer structure is subjected to a post-annealing step in which the multilayer structure is subjected to a temperature of about 300-1000° C. for a time sufficient to result in substantial diffusion of metal into voids between the carbon nanotubes and metal, thereby substantially eliminating such voids.

10. The method of claim 9 , wherein said post-annealing step is conducted in an atmosphere having a reduced level of oxygen.

11. The method of claim 1 , wherein said metal substrate is a metal-containing foil, tape, or wire.

12. The method of claim 11 , wherein said metal-containing foil, tape, or wire has a thickness of at least 1 micron.

13. The method of claim 11 , wherein said metal-containing foil, tape, or wire has a thickness of at least 10 microns.

14. The method of claim 11 , wherein said metal-containing foil, tape, or wire has a thickness of at least 25 microns.

15. The method of claim 1 , wherein said carbon nanotubes are included in an amount of at least 1 vol % by volume of the carbon nanotube-metal composite.

16. The method of claim 1 , wherein said carbon nanotubes are sufficiently aligned to result in said carbon nanotube-metal composite possessing room temperature electrical and thermal conductivities exceeding those of the metal alone.

17. The method of claim 1 , wherein a surfactant is included in said liquid suspension to improve dispersion of carbon nanotubes in the liquid suspension and to induce deformability of said liquid suspension when subjected to said shearing force.

18. The method of claim 2 , wherein said droplets are produced from a feed solution containing said liquid in which carbon nanotubes are suspended, and said feed solution is contained in and delivered from a syringe pump.

19. The method of claim 1 , wherein said metal comprises an element selected from the group consisting of copper, titanium, iron, cobalt, nickel, zinc, palladium, platinum, silver, gold, rhodium, iridium, ruthenium, magnesium, silicon, germanium, and tin.

20. The method of claim 1 , wherein said metal comprises copper.

21. A method for producing a carbon nanotube-metal composite in which carbon nanotubes are layered on a metal substrate, the method comprising:
(i) spreading a liquid in which carbon nanotubes are suspended over said metal substrate;
(ii) during or after step (i), subjecting said liquid, while spread over said metal substrate, to a shearing force sufficient to spatially confine the liquid suspension to induce at least partial alignment of said carbon nanotubes;
(iii) removal of said liquid to produce said carbon nanotube-metal composite; wherein, after step (iii), the lengthwise dimensions of said carbon nanotubes are adhered to and oriented parallel with said metal surface, and said carbon nanotubes are at least partially aligned with each other; and
(iv) coating a layer of metal onto the at least partially aligned carbon nanotubes to result in said carbon nanotubes sandwiched between said metal substrate and an overlayer of said metal, wherein said overlayer of metal is deposited by sputter deposition.

Assignees

• Ut Battelle Llc

Inventors

• Aytug Tolga
• Ivanov Ilia N
• Yoon Mina
• Meng Xiangtao
• Ozcan Soydan

Classifications

• C01B32/172 Primary

  Sorting · CPC title

• B32B2315/00

  Other materials containing non-metallic inorganic compounds not provided for in groups B32B2311/00 - B32B2313/04 · CPC title

• B32B15/20

  comprising aluminium or copper {(B32B15/016 and B32B15/017 take precedence)} · CPC title

• B32B2250/03

  3 layers · CPC title

• C01B32/174

  Derivatisation; Solubilisation; Dispersion in solvents · CPC title