Electroconductive Carbon Fibril-based Inks and Coatings

• US 20080111110A1
• Filed: 08/20/2007
• Published: 05/15/2008
• Est. Priority Date: 06/14/2002
• Status: Active Grant

• Current Assignee: Hyperion Catalysis International Incorporated
• Original Assignee: Hyperion Catalysis International Incorporated
• Inventors: Fischer, Alan B., Niu, Chunming, Ma, Jun, Ngaw, Lein
• Granted Patent: US 7,852,613 B2
• Time in Patent Office: Days
• US Class Current: 252/500
• CPC Class Codes: C09D 11/52 Electrically conductive inks
• CPC Class Codes: C09D 5/24 Electrically-conducting paints conductive materials H01B1/00
• CPC Class Codes: H01B 1/24 the conductive material comprising carbon-silicon compounds, carbon or silicon
• CPC Class Codes: H01C 17/0652 containing carbon or carbides
• CPC Class Codes: H01C 17/06586 composed of organic material
• CPC Class Codes: H01G 11/24 characterised by structural features of the materials making up or comprised in the electrodes, e.g. form, surface area or porosity; characterised by the structural features of powders or particles used therefor
• CPC Class Codes: H01G 11/38 Carbon pastes or blends; Binders or additives therein
• CPC Class Codes: Y02E 60/13 Energy storage using capacitors
• CPC Class Codes: Y10S 977/742 Carbon nanotubes, CNTs
• CPC Class Codes: Y10T 428/25 Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
• CPC Class Codes: Y10T 428/29 Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
• CPC Class Codes: Y10T 428/30 Self-sustaining carbon mass or layer with impregnant or other layer

Abstract

The present invention relates to electroconductive inks and methods of making and using the same. The electroconductive inks include carbon fibrils and a liquid vehicle. The electroconductive ink may further include a polymeric binder. The electroconductive filler used is carbon fibrils which may be oxidized. The ink has rheological properties similar to that of commercially available electroconductive inks that use carbon black as their filler. The ink can be screen-printed, slot-coated, sprayed, brushed or dipped onto a wide variety of substrates to form an electroconductive coating.

Claims

1. An electroconductive ink comprising:

substantially cylindrical carbon fibrils having one or more graphitic layers concentric with their cylindrical axes, said carbon fibrils being substantially free of pyrolytically deposited carbon overcoat, having a substantially uniform diameter between 0.4 nm and 100 nm, having a length to diameter ratio greater than 5; and

a liquid vehicle;

wherein said electroconductive ink has a viscosity ranging from 1 to 50,000 cps.

58. The electroconductive ink of claim 1, further comprising a polymeric binder.

59. The electroconductive ink of claim 58, wherein said polymeric binder is selected from the group consisting of vinyl chloride, vinyl acetate, hydroxyalkyl acrylate, vinyl alcohol, cellulose acetate butyrate, hydroxylethyl cellulose, carboxylmethyl cellulose, acrylic-based polymers, and combinations thereof.

60. The electroconductive ink of claim 1, wherein said liquid vehicle is a nonhydrocarbon polar organic solvent.

61. The electroconductive ink of claim 1, wherein said carbon fibrils are in the form of aggregates.

65. A method of preparing an electroconductive coating using the electroconductive ink of claim 1 comprising screen printing said ink to form said coating.

66. A method of preparing an electroconductive coating using the electroconductive ink of claim 1 comprising ink jet printing said ink to form said coating.

67. A method of preparing an electroconductive coating using the electroconductive ink of claim 1 comprising spraying the ink through a mask to form said coating.

68. A field emission cathode comprising a coating made according to the method of claim 65.

69. A field emission cathode operating at between 0.1 and 2.0 v/μ

m, having a patterned cathode with features smaller than 1 mm, prepared using the electroconductive ink according to claim 1.

70. A supercapacitor comprising a printed electrode comprising an electroconductive coating made according to the method of claim 65.

71. A printed resistor comprising an electroconductive coating made according to the method of claim 65.

72. The electroconductive ink of claim 58, wherein said liquid vehicle is a nonhydrocarbon polar organic solvent.

73. The electroconductive ink of claim 58, wherein said liquid vehicle is selected from the group consisting of carbitol, carbitol acetate, butyl carbitol, butyl carbitol acetate, butyrolactone, acetone, methyl ethyl ketone, cyclohexanone, dibasic ester solvent, diglyme, high boiling alcohols, alcohol esters and combinations thereof.

74. The electroconductive ink of claim 72, wherein said organic solvent has a boiling point from about 150°

C. to 200°

C.

75. The electroconductive ink of claim 58, wherein said liquid vehicle is water.

76. The electroconductive ink of claim 58, wherein the carbon fibrils are present in the range of from about 1 to about 5 percent by weight of the electroconductive ink.

77. The electroconductive ink of claim 58, wherein said carbon fibrils are in the form of aggregates.

79. An electroconductive coating made using the conductive ink of claim 58.

80. An electroconductive coating made using the conductive ink of claim 61.

81. A field emission cathode operating at between 0.1 and 2.0 v/μ

m, having a patterned cathode with features smaller than 1 mm, prepared using the electroconductive ink according to claim 58.

62. An electroconductive coating comprising:

substantially cylindrical carbon fibrils having one or more graphitic layers concentric with their cylindrical axes, said carbon fibrils being substantially free of pyrolytically deposited carbon overcoat, said carbon fibrils having a substantially uniform diameter between 0.4 nm and 100 nm, said fibrils having a length to diameter ratio greater than 5, wherein said coating has a resistivity of 0.001 to 0.25 ohm cm.

63. An electroconductive coating of claim 62 further comprising a polymeric binder.

64. An electroconductive coating of claim 62, wherein said carbon fibrils are in the form of aggregates.

78. The electroconductive coating of claim 63, wherein said carbon fibrils are in the form of aggregates.