SUPERCAPACITOR HAVING ELECTRODE MATERIAL COMPRISING SINGLE-WALL CARBON NANOTUBES AND PROCESS FOR MAKING THE SAME

• US 20060098389A1
• Filed: 06/30/2003
• Published: 05/11/2006
• Est. Priority Date: 07/01/2002
• Status: Active Grant

• Current Assignee: Georgia Tech Research Corporation (University System of Georgia)
• Original Assignee: Georgia Tech Research Corporation (University System of Georgia)
• Inventors: Kumar, Satish, Liu, Tao
• Granted Patent: US 7,061,749 B2
• Time in Patent Office: Days
• US Class Current: 361/502
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: H01G 11/12 Stacked hybrid or EDL capacitors
• CPC Class Codes: H01G 11/22 Electrodes
• CPC Class Codes: H01G 11/34 characterised by carbonisation or activation of carbon
• CPC Class Codes: H01G 11/36 Nanostructures, e.g. nanofibres, nanotubes or fullerenes
• CPC Class Codes: H01G 11/38 Carbon pastes or blends; Binders or additives therein
• CPC Class Codes: H01G 11/56 Solid electrolytes, e.g. gels; Additives therein
• CPC Class Codes: Y02E 60/13 Energy storage using capacitors

Abstract

The present invention relates to a supercapacitor, also known as an electrical double-layer capacitor or ultracapacitor, having electrode material comprising single-wall carbon nanotubes. The carbon nanotubes can be derivatized with functional groups. The electrode material is made by preparing a polymer-nanotube suspension comprising polymer and nanotubes, forming the polymer-nanotube suspension into a polymer-nanotube composite of the desired form, carbonizing the polymer-nanotube composite to form a carbonaceous polymer-nanotube material, and activating the material. The supercapacitor includes electrode material comprising activated carbonaceous polymer-nanotube material in contact with current collectors and permeated with an electrolyte, which may be either fluid or solid. In the case of a fluid or compressible electrolyte, an electrolyte-permeable separator or spacer is interposed between the electrodes to keep the electrodes from shorting. The supercapacitor made with electrodes comprising underivatized single-wall carbon nanotubes and polymer that has been carbonized and activated appears to operate as a non-Faradaic supercapacitor.

Claims

1-32. -32. (canceled)

33. A supercapacitor comprising:

(a) at least two electrodes comprising an activated carbonaceous polymer-nanotube material comprising single-wall carbon nanotubes and polymer, wherein the polymer is poly(acrylonitrile-methyl acrylate) copolymer or poly(acrylonitrile-itaconic acid-methyl acrylate) copolymer, and wherein the polymer-nanotube material was pyrolyzed and activated;

(b) at least two current collectors, each in contact with an electrode, wherein the current collector comprises a conducting material; and

(c) an electrolyte interposed between the electrodes.

34. The supercapacitor of claim 33 further comprising a non-conducting separator in between the at least two electrodes.

35. The supercapacitor of claim 34 wherein the separator is permeable by the electrolyte.

36. The supercapacitor of claim 34 wherein the separator comprises a material selected from the group consisting of hydrophilic polyethylene, fiberglass mat and porous glass paper.

37. The supercapacitor of claim 33 wherein the electrolyte comprises an aqueous solution of a compound selected from the group consisting of sulfuric acid, potassium hydroxide, and sodium hydroxide.

38. The supercapacitor of claim 33 wherein the electrolyte comprises a tetraalkylammonium salt.

39. The supercapacitor of claim 33 wherein the electrolyte comprises an organic carbonate selected from the group consisting of ethylene carbonate, propylene carbonate, propanediol-1,2-carbonate and dichloroethylene carbonate.

40. The supercapacitor of claim 33 wherein the electrolyte comprises a polymer gel electrolyte selected from the group consisting of polyurethane-LiCF₃SO₃, polyurethane-lithium perchlorate, polyvinylacohol-KOH—

H₂O, poly(acrylonitrile)-lithium salts, poly(acrylonitrile)-quaternary ammonium salts, and poly(ethylene oxide)-grafted poly(methyl)-methacrylate-quaternary ammonium salts.

41. The supercapacitor of claim 33 wherein the conducting material comprises a material selected from the group consisting of copper, aluminum, nickel and stainless steel.

46. The supercapacitor of claim 33 wherein the single-wall carbon nanotubes are derivatized with a functional group.

47. The supercapacitor of claim 33 wherein the single-wall carbon nanotubes and the polymer are in a weight ratio in the range of about 99:

1 and about 1;

99.

48. The supercapacitor of claim 33 wherein the single-wall carbon nanotubes and the polymer are in a weight ratio in the range of about 80:

20 and about 20;

80.

49. The supercapacitor of claim 33 wherein the polymer-nanotube material was activated by heating in carbon dioxide.

50. The supercapacitor of claim 33 wherein the electrode is a form selected from the group consisting of a film, fiber, fabric, felt, mat and combinations thereof.

51. The supercapacitor of claim 33 wherein the electrode is a film.

52. The supercapacitor of claim 33 wherein the electrode is a fabric.

53. The supercapacitor of claim 52 wherein the fabric is nonwoven.

54. The supercapacitor of claim 33 wherein the carbonaceous polymer-nanotube material is a fiber.

55. The supercapacitor of claim 33 herein the activation is done in a gaseous atmosphere comprising carbon dioxide.

56. The supercapacitor of claim 33 wherein the electrolyte is organic or aqueous.

57. The supercapacitor of claim 33 wherein the electrolyte comprises a compound selected from the group consisting of sulfuric acid, potassium hydroxide, sodium hydroxide, and combinations thereof.

58. The supercapacitor of claim 33 wherein the electrolyte comprises a compound selected from the group consisting of quaternary ammonium salts, ethylene carbonate, propylene carbonate, propanediol-1,2-carbonate, dichloroethylene carbonate, and combinations thereof.

59. The supercapacitor of claim 33 wherein the electrolyte is a polymer gel electrolyte.

61. The supercapacitor of claim 33 wherein the supercapacitor is a bi-polar stacked capacitor.

62. The supercapacitor of claim 33 wherein the supercapacitor is a spiral-wound capacitor.

64. The supercapacitor of claim 33 wherein the supercapacitor is an on-chip all-solid-state thin film supercapacitor.

65. The supercapacitor of claim 33 wherein the supercapacitor is a component of a microelectronic mechanical system (MEMS).

42-45. -45. (canceled)

60. (canceled)

63. A supercapacitor comprising:

(a) at least two electrodes comprising an activated carbonaceous polymer-nanotube material comprising single-wall carbon nanotubes and polymer, wherein the polymer-nanotube material was pyrolyzed and activated;

(b) at least two current collectors, each in contact with an electrode, wherein the current collector comprises a conducting material; and

(c) an electrolyte interposed between the electrodes;

wherein the supercapacitor is a non-Faradaic supercapacitor.

66. An electrode comprising an activated carbonaceous polymer-nanotube material comprising single-wall carbon nanotubes and polymer, wherein the polymer is poly(acrylonitrile-methyl aculeate) copolymer or poly(acrylonitrile-itaconic acid-methyl acrylate) copolymer, and wherein the polymer-nanotube material was pyrolyzed and activated.

72. The electrode of claim 66 wherein the single-wall carbon nanotubes are derivatized with a functional group.

73. The electrode of claim 66 wherein the single-wall carbon nanotubes and the polymer are in a weight ratio in the range of about 99:

1 and about 1;

99.

74. The electrode of claim 66 wherein the single-wall carbon nanotubes and the polymer are in a weight ratio in the range of about 80:

20 and about 20.80.

75. The electrode of claim 66 wherein the polymer-nanotube material was activated by heating in carbon dioxide.

76. The electrode of claim 66 wherein the electrode is a form selected from the group consisting of a film, fiber, fabric, felt, mat and combinations thereof.

77. The electrode of claim 66 wherein the electrode is a fabric.

78. The electrode of claim 77 wherein the fabric is nonwoven.

79. The electrode of claim 66 wherein the carbonaceous polymer-nanotube material is a fiber.

80. The electrode of claim 66 wherein the activation is done in a gaseous atmosphere comprising carbon dioxide.

67-71. -71. (canceled)