Electrically conductive, freestanding microporous sheet for use in an ultracapacitor

• US 6,704,192 B2
• Filed: 10/10/2001
• Issued: 03/09/2004
• Est. Priority Date: 02/19/1999
• Status: Expired due to Term

• Current Assignee: Amtek Research International LLC
• Original Assignee: Amtek Research International LLC
• Inventors: Pekala, Richard W.
• Primary Examiner(s): Dinkins, Anthony
• Assistant Examiner(s): HA, NGUYEN T
• Application Number:
  US09/975,288
• Publication Number:
  US 20020080553A1
• Time in Patent Office: 881 Days
• Field of Search: 361/502, 361/503, 361/508, 361/509, 361/523, 361/525, 361/528, 361/518, 361/519, 361/504, 361/510, 361/512, 29/250.3
• US Class Current: 361/502
• CPC Class Codes: H01G 11/26 characterised by their structure, e.g. multi-layered, porosity or surface features
• CPC Class Codes: H01G 11/28 arranged or disposed on a current collector; Layers or phases between electrodes and current collectors, e.g. adhesives
• CPC Class Codes: H01G 11/32 Carbon-based
• CPC Class Codes: H01G 11/46 Metal oxides
• CPC Class Codes: H01G 11/48 Conductive polymers
• CPC Class Codes: H01G 9/042 characterised by the material H01G11/22 takes precedence
• CPC Class Codes: H01M 4/50 of manganese
• CPC Class Codes: H01M 4/622 being polymers
• CPC Class Codes: H01M 4/623 fluorinated polymers
• CPC Class Codes: H01M 4/8605 Porous electrodes
• CPC Class Codes: H01M 4/8875 Methods for shaping the electrode into free-standing bodies, like sheets, films or grids, e.g. moulding, hot-pressing, casting without support, extrusion without support
• CPC Class Codes: H01M 4/96 Carbon-based electrodes
• CPC Class Codes: H01M 50/417 Polyolefins
• CPC Class Codes: H01M 50/46 Separators, membranes or diaphragms characterised by their combination with electrodes
• CPC Class Codes: H01M 8/1004 characterised by membrane-electrode assemblies [MEA] H01M8/12 takes precedence
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/13 Energy storage using capacitors
• CPC Class Codes: Y02E 60/50 Fuel cells
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

A freestanding, microporous polymer sheet is composed of a polymer matrix binding an electrically conductive matrix. The polymer matrix preferably includes UHMWPE, and the electrically conductive matrix preferably contains one of a carbonaceous material and a metal oxide, or a combination thereof. The UHMWPE is of a molecular weight that provides sufficient molecular chain entanglement to form a sheet with freestanding characteristics. Multiple microporous sheets can be wound or stacked in a package filled with an electrolyte to function as electrodes in an energy storage device, such as a battery or an ultracapacitor.

Claims

1. A freestanding microporous polymer web, comprising:

a polymer matrix binding a material composition having electrical conductivity properties, the polymer matrix including an ultrahigh molecular weight polyolefin and the material composition having electrical conductivity properties and including one of a carbonaceous material and a metal oxide, or a combination thereof, and the ultrahigh molecular weight polyolefin being of a molecular weight that provides sufficient molecular chain entanglement to form a microporous web with freestanding characteristics.

2. The polymer web of claim 1, in which the ultrahigh molecular weight polyolefin is ultrahigh molecular weight polyethylene.

3. The polymer web of claim 2, in which the ultrahigh molecular weight polyethylene is present in an amount equal to or less than about 20 percent by volume.

4. The polymer web of claim 1, in which the carbonaceous material is one of carbon aerogel, activated carbon, and high surface area carbon.

5. The polymer web of claim 1, in which the metal oxide is one of ruthenium oxide, lead oxide, tantalum oxide, manganese dioxide, and nickel oxide.

6. The polymer web of claim 1, further including a metallic layer that is applied to the polymer web to form a metallized electric current collector.

7. The polymer web of claim 6, in which the metallic layer includes one of a metallic grid, perforated metal sheet, metal film, and metal foil.

8. The polymer web of claim 6, in which the metallic layer includes one of a metal film formed by sputter deposition on, electroless deposition on, electrodeposition on, plasma spraying on, or roll coating of a metal slurry on the microporous web;

or a porous or nonporous metal foil laminated to the microporous web.

9. An ultracapacitor having multiple layers, comprising:

a separator layer positioned between first and second porous electrode layers, each of which includes a mixture of ultrahigh molecular weight polyolefin;

each of the first and second porous electrode layers including a polymer matrix binding a material composition having electrical conductivity properties, the polymer matrix including an ultrahigh weight polyolefin and one of a carbonaceous material and a metal oxide, or a combination thereof, and the ultrahigh molecular weight polyolefin being of a molecular weight that provides sufficient molecular chain entanglement to form a microporous web with freestanding characteristics;

a pair of current collectors each of which is bonded to a different one of the first and second porous electrode layers; and

an electrolyte in contact with the multiple layers.

10. The ultracapacitor of claim 9, in which the ultrahigh molecular weight polyolefin is ultrahigh molecular weight polyethylene.

11. The ultracapacitor of claim 10, in which the ultrahigh molecular weight polyethylene in the electrode layers is present in an amount equal to or less than about 20 percent by volume.

12. The ultracapacitor of claim 9, which the separator layer includes an ultrahigh molecular weight polyolefin.

13. The ultracapacitor of claim 12, in which the ultrahigh molecular weight polyolefin is ultrahigh molecular weight polyethylene.

14. The ultracapacitor of claim 9, in which the material composition contains one of carbon aerogel, ruthenium oxide, manganese dioxide, nickel oxide, or tantalum oxide.

15. The ultracapacitor of claim 9, in which the electrode layers exhibit pseudocapacitance.

16. The ultracapacitor of claim 9, in which the first porous electrode layer exhibits pseudocapacitance and the second porous electrode layer exhibits double capacitance.