Method of Fabrication of Carbon Nanofibers on Nickel Foam

• US 20120154983A1
• Filed: 10/06/2011
• Published: 06/21/2012
• Est. Priority Date: 10/08/2010
• Status: Abandoned Application

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Zhang, Yuegang, Cui, Yi, Choi, Jang Wook, McDonough, James
• Application Number:
  US13/267,559
• Publication Number:
  US 20120154983A1
• Time in Patent Office: Days
• US Class Current: 361/502
• CPC Class Codes: B22F 2998/10 Processes characterised by the sequence of their steps
• CPC Class Codes: B22F 2999/00 Aspects linked to processes or compositions used in powder metallurgy
• CPC Class Codes: B22F 3/11 Making porous workpieces or articles
• CPC Class Codes: B22F 3/1146 After-treatment maintaining the porosity B22F3/114 takes precedence
• CPC Class Codes: B22F 7/002 of porous nature
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: C22C 26/00 Alloys containing diamond or cubic or wurtzitic boron nitride, fullerenes or carbon nanotubes
• CPC Class Codes: C23C 16/00 Chemical coating by decomposition of gaseous compounds, without leaving reaction products of surface material in the coating, i.e. chemical vapour deposition [CVD] processes reactive sputtering or vacuum evaporation C23C14/00
• CPC Class Codes: C23C 16/045 Coating cavities or hollow spaces, e.g. interior of tubes; Infiltration of porous substrates
• CPC Class Codes: C23C 16/403 of aluminium, magnesium or beryllium
• CPC Class Codes: C23C 16/45525 Atomic layer deposition [ALD]
• CPC Class Codes: D01F 9/127 by thermal decomposition of hydrocarbon gases or vapours or other carbon-containing compounds in the form of gas or vapour, e.g. carbon monoxide, alcohols
• CPC Class Codes: H01G 11/36 Nanostructures, e.g. nanofibres, nanotubes or fullerenes
• CPC Class Codes: Y02E 60/13 Energy storage using capacitors
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y10T 428/24999 Inorganic

Abstract

A method for forming a novel composite of carbon nanofibers grown on a nickel foam is described wherein the composite, when used in a capacitor exhibits superior change retention and discharge capacities. Once the composite material has been obtained, it may be formed into electrodes which can be used to form supercapacitors of large per area capacitances in the order of 1.2 F/cm².

Claims

1. A method for forming a composite of carbon nanofibers on a metal foam base comprising:

providing a metal foam base;

depositing one or more atomic layers of alumina over said metal foam base; and

, thereafter forming carbon nanofibers on said alumina coasted metal foam base.

2. The method of claim 1 wherein the metal foam base is a nickel foam.

3. The article of claim 2 wherein the nickel foam has a porosity of about 95%.

4. The method of claim 1 wherein the deposition of the alumina over the metal foam base is performed using atomic layer deposition.

5. The method of claim 4 wherein the depositing step further includes the steps of:

establishing a constant flow of N₂ through an atomic layer deposition reaction chamber;

introducing a short pulse of H₂O into said atomic layer deposition reaction chamber;

continuing to flow N₂ for a predetermined interval of time;

introducing a short pulse of trimethyl aluminum into said reaction chamber;

continuing to flow N₂ for a second predetermined interval of time; and

repeating the above steps until the desired number of atomic layers of alumina has been obtained.

6. The method of claim 1 wherein the one or more deposited atomic layers of alumina contains multiple pathways allowing for the diffusion of metal from the foam to the surface of the alumina layer.

7. The method of claim 1 wherein the carbon nanofibers are formed by flowing a mixture of H₂, and C₂H₄ in an argon carrier gas into a CVD chamber maintained at an elevated temperature.

8. The method of claim 7 wherein the elevated temperature is maintained at above 410°

C.

9. The method of claim 7 wherein the elevated temperature is maintained at between about 440°

C. to 470°

C.

10. The method of claim 7 in which the formation step is carried out for about 20 to 30 minutes.

11. A carbon nanofiber on metal foam composite made according to the method of claim 1.

12. The carbon nanofiber on metal foam composite of claim 10 wherein the carbon nano fibers are solid fibers.

13. A supercapacitor made using the carbon nanofiber on metal foam composite of claim 11.

14. The supercapacitor of claim 13 wherein a separator is sandwiched in between two carbon nanofiber on nickel foam electrodes, each electrode in contact with a current collector.

15. The supercapacitor of claim 13 further including an electrolyte disposed between the electrodes.

16. The supercapacitor of claim 15 wherein the electrolyte is an aqueous solution of Li₂SO₄.