High energy density double layer energy storage devices

• US 5,905,629 A
• Filed: 07/23/1997
• Issued: 05/18/1999
• Est. Priority Date: 09/28/1995
• Status: Expired due to Term

• Current Assignee: Ingevity South Carolina, LLC (Ingevity Corp.)
• Original Assignee: Westvaco Corporation (Meadwestvaco Corporation)
• Inventors: Alford, John A.
• Primary Examiner(s): Kincaid, Kristine
• Assistant Examiner(s): Dinkins, Anthony
• Application Number:
  US08/898,771
• Time in Patent Office: 664 Days
• Field of Search: 361/502, 361/503, 361/504, 361/508, 361/512, 361/523, 361/525, 361/526, 361/528, 361/516, 361/532, 29/25.03, 502/416, 502/418, 502/62, 502/432, 502/433
• US Class Current: 361/502
• 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 11/34 characterised by carbonisation or activation of carbon
• CPC Class Codes: H01G 11/44 Raw materials therefor, e.g. resins or coal
• CPC Class Codes: Y02E 60/13 Energy storage using capacitors

Abstract

The present invention relates to lignocellulosic-based carbon-containing double layer energy storage devices having improved electrical energy densities. In particular, the invention provides a double layer energy storage cell comprising a pair of electrodes, at least one of which is a carbon paste electrode, a porous ionically conductive separator, and an ion insulating collector, the improvement wherein said carbon paste electrode includes an activated lignocellulosic-based carbon having a pore volume of greater than about 0.45 cc/g, a median pore width of less than 2.0 nm, a specific surface area of greater than about 500 m² /g, and a micropore content, based on the total particle volume of the activated carbon, of greater than about 75%.

Claims

1. A double layer energy storage cell with improved energy density, said cell comprising a pair of electrodes wherein at least one of said electrodes being a carbon paste electrode, a porous ionically conductive separator, and an ion insulating collector, the improvement wherein said carbon paste electrode comprises an activated lignocellulosic-based carbon having a pore volume of greater than about 0.45 cc/g, a median pore width of less than 2.0 nm, a specific surface area of greater than about 500 m² /g, and a micropore content, based on the total particle volume of the activated carbon, of greater than about 75%.

2. The cell of claim 1 wherein the activated carbon exhibits a pore volume of greater than about 0.50 cc/g.

3. The cell of claim 1 wherein the activated carbon exhibits a specific surface area of about 1,000 m² /g to about 2,500 m² /g.

4. The cell of claim 1 wherein the activated carbon exhibits, based on the total particle volume of said activated carbon, a micropore content of greater than about 90%.

5. The cell of claim 1 wherein the activated carbon exhibits, based on the total particle volume of said activated carbon, a micropore content of greater than about 99%.

6. The cell of claim 1 wherein the carbon paste electrode contains an aqueous electrolyte.

7. The carbon paste electrode of claim 6 wherein the lignocellulosic-based carbon is derived from wood.

8. A double layer energy storage cell with improved energy density comprising a plurality of electrical double layer energy storage cells, said cells each comprising a pair of electrodes wherein at least one of said electrodes being a carbon paste electrode, a porous ionically conductive separator, and an ion insulating collector, the improvement wherein said carbon paste electrode comprise an activated lignocellulosic-based carbon having a pore volume of greater than about 0.45 cc/g, a median pore width of less than 2.0 nm, a specific surface area of greater than about 500 m² /g, a micropore content based on the total particle volume of the activated carbon, of greater than about 75%.

9. The cell of claim 8 wherein the activated carbon exhibits a pore volume of greater than about 0.50 cc/g.

10. The cell of claim 8 wherein the activated carbon exhibits a specific surface area of about 1,000 m² /g to about 2,500 m² /g.

11. The cell of claim 8 wherein the activated carbon exhibits, based on the total carbon particle volume of said activated carbon, a micropore content greater than about 90%.

12. The cell of claim 8 wherein the activated carbon exhibits, based on the total carbon particle volume of said activated carbon, a micropore content of greater than about 99%.

13. The cell of claim 8 wherein the carbon paste electrode contains an aqueous electrolyte.

14. The carbon paste electrode of claim 8 wherein the lignocellulosic-based carbon is derived from wood.