Doped-carbon nano-architectured structures and methods for fabricating same

Patent metadata

Field	Value
Publication number	US-9842667-B2
Application number	US-201013702003-A
Country	US
Kind code	B2
Filing date	Dec 27, 2010
Priority date	Jun 26, 2009
Publication date	Dec 12, 2017
Grant date	Dec 12, 2017

Abstract

In an exemplary method, a nano-architectured carbon structure is fabricated by forming a unit (e.g., a film) of a liquid carbon-containing starting material and at least one dopant. A surface of the unit is nano-molded using a durable mold that is pre-formed with a pattern of nano-concavities corresponding to a desired pattern of nano-features to be formed by the mold on the surface of the unit. After nano-molding the surface of the unit, the first unit is stabilized to render the unit and its formed nano-structures capable of surviving downstream steps. The mold is removed from the first surface to form a nano-molded surface of a carbonization precursor. The precursor is carbonized in an inert-gas atmosphere at a suitable high temperature to form a corresponding nano-architectured carbon structure. A principal use of the nano-architectured carbon structure is a carbon electrode used in, e.g., Li-ion batteries, supercapacitors, and battery-supercapacitor hybrid devices.

First claim

What is claimed is:

1. A method for fabricating a nano-architectured doped carbon structure, comprising:
preparing a carbon-containing starting material including at least one dopant;
wherein preparing the carbon-containing starting material comprises preparing a suspension of nano-particles in a solvent for a polymerizable carbon-containing substance, and adding the carbon-containing polymerizable substance to the suspension;
nano-molding a surface of the starting material, using a durable mold pre-formed with a pattern of nano-concavities corresponding to a desired patterned array of nano-pillars to be formed by the mold on the surface, by bringing together the surface of the starting material and the pattern of nano-concavities without applying pressure;
removing the solvent;
when the nano-pillars formed by the mold on the surface of the starting material have reached at least a threshold level of self-supportability, non-destructively separating the mold and the nano-pillars from each other to form a carbonization precursor having a nano-pillar molded surface; and
carbonizing the precursor to form a corresponding array of nano-architectured carbon nano-pillars having diameters of less than 250 nm and height to diameter ratio greater than 1.5, wherein the method does not utilize ultra-violet light.

2. The method of claim 1 , wherein the dopant comprises a substance selected from a group consisting of metals and semiconductors.

3. The method of claim 2 , wherein the dopant comprises nano-particles of the substance.

4. The method of claim 1 , wherein:
the dopant comprises nano-particles of silicon; and
the carbon-containing polymerizable substance comprises polyacrylonitrile.

5. The method of claim 1 , wherein carbonization is performed under an elevated-temperature regimen and in an inert-atmosphere environment in which the precursor is converted to a corresponding nano-architectured carbon/activated carbon structure.

6. The method of claim 1 , wherein carbonization is performed under an elevated-temperature regimen and in an inert-atmosphere environment in which the precursor is converted to a corresponding nano-architectured graphite carbon structure.

7. The method of claim 1 , wherein the starting material is polyacrylonitrile (PAN), the method further comprising stabilizing the nano-molded starting material by incubation at a temperature at which molecules of the PAN are cyclized, the incubation being conducted in an atmosphere that prevents combustion of the precursor.

8. The method of claim 1 , wherein the nano-architectured doped carbon structure is a nano-architectured carbon electrode.

9. The method of claim 1 , wherein the mold and surface of the unit are separated from each other to form the carbonization precursor having a nano-pillar molded surface by contacting the mold with a substrate.

10. The method of claim 1 , further comprising, after separating the mold and the molded nano-pillars, stabilizing the molded nano-pillars prior to the carbonization of the precursor.

11. The method of claim 1 , wherein the height to diameter ratio is greater than 2.5.

12. A method for forming a nano-molded carbonization precursor, comprising:
forming a mold having a surface defining a desired pattern of nano-concavities corresponding to a desired patterned array of nano-pillars having a nano-pillar diameter of less than 250 nm and a height to diameter ratio greater than two;
preparing a starting material comprising a polymerizable carbon-containing substance and at least one dopant, the starting material being sufficiently fluid to have a moldable surface;
wherein preparing the starting material comprises preparing a suspension of nano-particles in a solvent for the polymerizable carbon-containing substance, and adding the suspension to the polymerizable carbon-containing substance;
bringing the surface of the mold and the starting material together without applying pressure such that the nano-concavities mold the desired patterned array of nano-pillars onto the moldable surface;
removing the solvent; and
when the nano-pillars formed by the mold on the moldable surface have reached at least a threshold level of self-supportability, non-destructively separating the mold and a surface of a unit of molded nano-pillars from each other to form a carbonization precursor having a nano-pillar molded surface, wherein the method does not utilize ultra-violet light.

13. The method of claim 12 , wherein the starting material is polyacrylonitrile (PAN).

14. A method for forming a nano-architectured carbon structure, comprising:
forming a mold;
in a surface of the mold, forming a desired pattern of nano-concavities corresponding to a desired patterned array of nano-pillars;
preparing a liquid starting material comprising a solvent, a polymerizable carbon-containing compound, and at least one dopant;
forming a film of the starting material having first and second surfaces;
using the mold, nano-molding the desired patterned array of nano-pillars into the first surface by contacting the mold and the first surface without applying pressure, the nano-pillars having a diameter of less than 250 nm;
removing the solvent and stabilizing the nano-molded film; and
non-destructively removing the mold from the first surface to form a carbonization precursor, wherein the method does not utilize ultra-violet light.

15. The method of claim 14 , wherein:
the liquid starting material is a carbon-containing starting material comprising at least one dopant; and
the method further comprises forming a carbonization precursor of the film, and carbonizing the precursor.

16. The method of claim 14 , wherein the starting material is polyacrylonitrile (PAN).

Assignees

• Thomas Jayan
• Gangopadhyay Palash
• Duong Binh Au Thanh
• Univ Arizona

Inventors

• Thomas Jayan
• Gangopadhyay Palash
• Duong Binh Au Thanh

Classifications

• Y10S977/70

  Nanostructure · CPC title

• Y10S977/932

  for electronic or optoelectronic application · CPC title

• Y10S977/887

  Nanoimprint lithography, i.e. nanostamp · CPC title

• H01B13/00

  Apparatus or processes specially adapted for manufacturing conductors or cables · CPC title

• H01M4/587

  for inserting or intercalating light metals · CPC title