NEGATIVE ELECTRODE CURRENT COLLECTOR FOR HETEROGENEOUS ELECTROCHEMICAL CAPACITOR AND METHOD OF MANUFACTURE THEREOF

• US 20080218938A1
• Filed: 02/19/2008
• Published: 09/11/2008
• Est. Priority Date: 02/19/2007
• Status: Active Grant

• Current Assignee: Universal Supercapacitors, LLC
• Original Assignee: Universal Supercapacitors, LLC
• Inventors: Litvinenko, Sergey Vitalievich, Kharisov, Gamir Galievich, Razumov, Sergey Nikolaevich, Kazaryan, Samvel Avakovich, Kazarov, Vladimir Alexandrovich
• Granted Patent: US 8,472,163 B2
• Time in Patent Office: Days
• US Class Current: 361/502
• CPC Class Codes: H01G 11/58 Liquid electrolytes
• CPC Class Codes: H01G 11/68 characterised by their material
• CPC Class Codes: H01G 11/70 characterised by their structure
• CPC Class Codes: H01G 11/84 Processes for the manufacture of hybrid or EDL capacitors, or components thereof
• CPC Class Codes: Y02E 60/13 Energy storage using capacitors

Abstract

A current collector for use in an electric double layer electrochemical capacitor having a sulfuric acid electrolyte. The current collector uses a conducting carbon (e.g., graphite foil) basis with p-type conductivity. A protective film covers at least a portion of the graphite foil basis. The protective film is comprised of a conducting composite material made with a conducting carbon and a conducting organic polymer with p-type conductivity. The protective film is grown on the current collector basis such that it preferably fills the pores of the current collector basis. A lug portion of the current collector basis may be protected with an insulating polymer material.

Claims

1. A current collector for use in an electric double layer electrochemical capacitor having a sulfuric acid electrolyte, comprising:

a current collector basis made from a conductive carbon-based active material of p-type conductivity; and

a protective film covering at least a portion of said current collector basis and filling the pores thereof, said protective film further comprising a conductive composite material made from a conducting carbon powder and an organic polymer with p-type conductivity.

2. The current collector of claim 1, wherein said current collector basis is comprised of a graphite foil.

3. The current collector of claim 2, wherein said graphite foil is made from a graphite powder(s) that is stable in an aqueous sulfuric acid electrolyte.

4. The current collector of claim 1, wherein said conducting organic polymer is selected from the group consisting of perchlorovinyl, chlorosulphated polyethylene, and fluorine-containing polymers.

5. The current collector of claim 1, wherein said conducting organic polymer further includes one or more materials selected from the group consisting of a plasticizer(s), a solvent(s), a dispersant, and a wetting agent(s).

6. The current collector of claim 1, wherein said protective film covers all but a lug and terminal portion of said current collector basis.

7. The current collector of claim 1, further comprising a coating of an insulating polymer material covering a lug portion of said current collector basis.

8. The current collector of claim 7, wherein said insulating polymer is an organic polymer with p-type conductivity.

9. The current collector of claim 1, wherein said carbon powder of said protective film has a particle size that is less than or equal to about 500 nm.

10. The current collector of claim 1, wherein the thickness of said protective film is between about 5 μ

m and about 15 μ

m.

11. The current collector of claim 1, wherein the thickness of said insulating polymer material coating is between about 15 μ

m and about 40 μ

m.

12. The current collector of claim 1, wherein the specific electrical resistance of said protective film is less than approximately 5.1 Ohm·

cm.

13. The current collector of claim 1, wherein the specific electric resistance of said protective film is between about 1.0 Ohm·

cm and about 5.0 Ohm·

cm.

14. A current collector for use in an electric double layer electrochemical capacitor having a sulfuric acid electrolyte, comprising:

a current collector basis made from a graphite foil having p-type conductivity;

a protective film covering and filling the pores of all but a lug and terminal portion of said graphite foil basis, said protective film further comprising a conductive composite material made from a conducting carbon powder and an organic polymer that both have p-type conductivity; and

an organic insulating polymer material covering a lug portion of said current collector basis, said insulating polymer material having p-type conductivity.

15. The current collector of claim 14, wherein said graphite foil is made from a graphite powder(s) that is stable in an aqueous sulfuric acid electrolyte.

16. The current collector of claim 14, wherein said conducting organic polymer is selected from the group consisting of perchlorovinyl, chlorosulphated polyethylene, and fluorine-containing polymers.

17. The current collector of claim 14, wherein said conducting organic polymer further includes one or more materials selected from the group consisting of a plasticizer(s), a solvent(s), a dispersant, and a wetting agent(s).

18. The current collector of claim 14, wherein said carbon powder of said protective film has a particle size that is less than or equal to about 500 nm.

19. The current collector of claim 14, wherein the thickness of said protective film is between about 5 μ

m and about 15 μ

m.

20. The current collector of claim 14, wherein the thickness of said insulating polymer material is between about 15 μ

m and about 40 μ

m.

21. The current collector of claim 14, wherein the specific electrical resistance of said protective film is less than approximately 5.1 Ohm·

cm.

22. A method of manufacturing a current collector for use in an electric double layer electrochemical capacitor having a sulfuric acid electrolyte, comprising:

cutting a current collector basis from a graphite foil having p-type conductivity;

preparing a conductive composite paste based on a conducting carbon powder and a conducting organic polymer that both have p-type conductivity placing an amount of said paste in a bath;

submerging at least a portion of said graphite foil basis in said conductive composite paste and subsequently sealing said bath for some period of time;

slowly reducing the level of said conductive composite paste in said bath so that a protective film of substantially uniform thickness grows over a contacted portion of said graphite foil basis;

removing said current collector from said bath;

air drying said current collector for some predetermined period of time; and

after air drying, subjecting said current collector to thermal treatment at an elevated temperature for some period of time.

23. The method of claim 22, wherein said current collector basis is lowered into said bath such that all but a lug and terminal portion of said current collector basis is contacted by said paste.

24. The method of claim 22, further comprising applying a coating of an insulating polymer material over said lug portion of said current collector basis.

25. The method of claim 22, wherein the level of said conductive composite paste in said bath is lowered at a rate of between about 0.5-1.5 cm/min.