CAPACITORS USING CARBON-BASED EXTENSIONS

• US 20100195263A1
• Filed: 02/02/2010
• Published: 08/05/2010
• Est. Priority Date: 02/02/2009
• Status: Abandoned Application

• Current Assignee: Space Charge, LLC
• Original Assignee: Space Charge, LLC
• Inventors: Sweeney, Daniel C., Read, John B.
• Application Number:
  US12/698,883
• Publication Number:
  US 20100195263A1
• Time in Patent Office: Days
• US Class Current: 361/321.1
• CPC Class Codes: H01G 11/22 Electrodes
• CPC Class Codes: H01G 4/008 Selection of materials
• CPC Class Codes: H01G 4/01 Form of self-supporting electrodes
• CPC Class Codes: H01G 4/1209 characterised by the ceramic dielectric material H01G4/1272, H01G4/1281 take precedence
• CPC Class Codes: Y10T 29/435 Solid dielectric type

Abstract

Devices for storing energy at a high density are described. The devices include carbon-containing extensions which increase the surface area between a dielectric material and one or both of the electrodes. The dielectric material may have a high dielectric constant (high permittivity) and a high breakdown voltage, allowing a high voltage difference between paired electrodes to effect a high stored energy density.

Claims

1. A storage capacitor for storing a high density of electrical charge comprising:

a first electrode with a first surface region having a first surface area and a second electrode with a second surface region having a second surface area,

wherein the second electrode is physically separated from the first electrode leaving a gap between the first and second electrodes to inhibit charge from flowing across the gap from one electrode to the other, and

wherein the first surface region comprises a plurality of carbon-containing extensions to increase the first surface area, wherein the plurality of carbon-containing extensions have a mean aspect ratio of greater than 5, a carbon-containing extension trunk coverage greater than 0.1% and each carbon-containing extension comprises sp²-bonded carbon; and

a dielectric slab of dielectric material disposed in the gap and contacting the first surface and the second surface, wherein the dielectric slab exhibits a high effective relative permittivity above or about 500.

2. The storage capacitor of claim 1 wherein the carbon-containing extensions consist essentially of carbon.

3. The storage capacitor of claim 1 wherein the carbon-containing extensions consist essentially of sp²-bonded carbon.

4. The storage capacitor of claim 1 wherein the carbon-containing extensions extend generally towards the second electrode.

5. The storage capacitor of claim 1 wherein the first surface region comprises carbon velvet.

6. The storage capacitor of claim 1 wherein the carbon-containing extensions comprise single-walled carbon nanotubes.

7. The storage capacitor of claim 1 wherein the carbon-containing extensions consist essentially of single-walled carbon nanotubes.

8. The storage capacitor of claim 1 the carbon-containing extension trunk coverage may be greater than one of 0.5%, 1%, 2%, 5% or 10%.

9. The storage capacitor of claim 1 wherein the carbon-containing extensions comprise carbon nanotubes having a mean length below about one of 100 nm, 50 nm, 20 nm or 10 nm.

10. The storage capacitor of claim 1 wherein the carbon-containing extensions comprise carbon nanotubes having a mean length above about one of 3 nm, 10 nm, 20 nm or 50 nm.

11. The storage capacitor of claim 1 wherein the second surface region also comprises carbon-containing extensions.

12. The storage capacitor of claim 1 wherein the high effective relative permittivity is greater than or about one of 1000 or 2000.

13. The storage capacitor of claim 1 wherein the dielectric material comprises a ceramic perovskite.

14. The storage capacitor of claim 13 wherein the dielectric material comprises tungsten bronze.

15. The storage capacitor of claim 1 wherein the first surface area is greater than an otherwise similar electrode made with a flat surface by a multiplicative factor greater than 4, 10, 50, 100 or 500.

16. The storage capacitor of claim 1 wherein the storage capacitor is configured to exhibit a breakdown voltage above or about 1 kV per millimeter, above or about 2 kV per millimeter or above or about 4 kV per millimeter.

17. A method of forming a storage capacitor, the method comprising:

providing a first electrode and a second electrode with a gap between them to inhibit charge from flowing from one electrode across the gap to the other, wherein the first electrode has a first surface region having a first surface area and the first surface region comprises carbon-containing extensions to increase the first surface area, wherein the plurality of carbon-containing extensions have a mean aspect ratio of greater than 5, a carbon-containing extension trunk coverage greater than 0.1% and each carbon-containing extension comprises sp²-bonded carbon; and

flowing a flowable dielectric between the first and second electrodes and in amongst the carbon-containing extensions; and

converting the flowable dielectric to a solid dielectric having a high effective relative permittivity above or about 500.

18. The method of claim 17 further comprising firing the solid dielectric at high temperature to increase the effective relative permittivity.

19. The method of claim 17 wherein the high effective relative permittivity is greater than or about one of 1000, 2000, 5000 or 10,000.

20. The method of claim 17 wherein the operation of flowing a flowable dielectric comprises the sequential steps of flowing a first flowable dielectric followed by flowing a second flowable dielectric, wherein a viscosity of the first flowable dielectric is less than the viscosity of the second flowable dielectric.

21. The method of claim 17 wherein the operation of flowing the flowable dielectric between the first and second electrodes further comprises flowing the dielectric in amongst the carbon-containing extensions whereby the contact area between the dielectric and the first metal electrode is greater than or about a contact area with an otherwise-similar untextured metal electrode by a multiplicative factor greater than one of 4, 10, 50, 100 or 500.

22. The method of claim 17 wherein the second metal electrode has a second surface region and a second surface area and the second surface region comprises second carbon-containing extensions.

23. The method of claim 22 wherein the operation of flowing the flowable dielectric between the first and second electrodes further comprises flowing the dielectric in amongst the second carbon-containing extensions whereby the contact area between the dielectric and the second metal electrode is greater than or about a contact area with an otherwise-similar untextured metal electrode by a multiplicative factor greater than one of 4, 10, 50, 100 or 500.

24. The method of claim 17 wherein the operation of converting the flowable dielectric to the solid dielectric comprises curing the flowable dielectric with at least one of an e-beam, ultraviolet light radiation or heat.

25. The method of claim 17 wherein the operation of converting the flowable dielectric to the solid dielectric comprises annealing the flowable dielectric.

26. The method of claim 17 wherein the flowable dielectric comprises solid granules of material whereby the effective relative permittivity of the solid dielectric is increased.