Activated carbon, method for production thereof, polarizing electrode and electrical double layer capacitor

• US 20050266990A1
• Filed: 07/03/2003
• Published: 12/01/2005
• Est. Priority Date: 07/30/2002
• Status: Active Grant

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company), Kuraray Company Limited
• Original Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company), Kuraray Chemical Co., Ltd. (Kuraray Company Limited)
• Inventors: Sugo, Nozomu, Iwasaki, Hideharu, Fujino, Takeshi, Oyama, Shigeki, Kawabuchi, Yuji, Nishimura, Shushi, Hitomi, Mitsunori
• Granted Patent: US 7,759,289 B2
• Time in Patent Office: Days
• US Class Current: 502/416
• CPC Class Codes: C01B 32/342 characterised by non-gaseous activating agents
• CPC Class Codes: H01G 11/34 characterised by carbonisation or activation of carbon
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/13 Energy storage using capacitors

Abstract

In activated carbon obtained by subjecting a carbonaceous material to an activation treatment, the overall content of alkali metals is set at 100 ppm or less, or the overall content of heavy metals is set at 20 ppm or less and the overall content of alkali metals is set at 200 ppm or less. In cases where such activated carbon is used as a raw material in electronic devices, the formation of dendrites by the reductive deposition of alkali metals or heavy metals tends not to occur, so that problems such as short-circuiting or the like tend not to arise, and a good rate of self-discharge retention is shown.

Claims

1. An activated carbon, obtained by subjecting a carbonaceous material to an activation treatment, wherein the overall content of alkali metals in said activated carbon is 100 ppm or less.

2. The activated carbon according to claim 1, wherein said alkali metals are sodium and/or potassium.

31. A polarizing electrodes which is formed by mixing the activated carbon according to claim 1, with at least a binder and a conductive material.

32. An electrical double layer capacitor, comprising the polarizing electrode according to claim 31.

3. An activated carbon manufacturing method, comprising subjecting a carbonaceous material to an activation treatment, and then washing the activation treatment product, thus obtained, with a liquid that contains carbonic acid to give the activated carbon.

4. An activated carbons, obtained by subjecting a carbonaceous material to an activation treatment, wherein the overall content of heavy metals in said activated carbon is 20 ppm or less.

5. The activated carbon according to claim 4, wherein said heavy metals comprise at least one metal selected from the group consisting of nickel, copper, zinc and iron.

6. The activated carbon according to claim 5, wherein said heavy metals comprise at least nickel, and wherein the nickel content is 8 ppm or less.

7. The activated carbon according to claim 5, wherein said heavy metals comprise at least zinc, and wherein the zinc content is 1 ppm or less.

8. The activated carbon according to claim 5, wherein said heavy metals comprise at least copper, and wherein the copper content is 1 ppm or less.

9. The activated carbon according to claim 5, wherein said heavy metals comprise at least iron, and wherein the iron content is 0.3 ppm or less.

10. An activated carbon manufacturing method, comprising subjecting a carbonaceous material to an activation treatment, and then washing the activation treatment product, thus obtained, with a liquid containing a basic substance to give the activated carbon.

11. An activated carbon, obtained by subjecting an easily graphitizable carbonaceous material to an alkali activation treatment, wherein, in said activated carbon, the overall content of heavy metals is 20 ppm or less, and the content of alkali metals is 200 ppm or less.

12. The activated carbon according to claim 11, wherein said heavy metals comprise at least one metal selected from the group consisting of nickel, copper, zinc and iron.

13. The activated carbon according claim 11, wherein said heavy metals comprise at least nickel, and wherein the nickel content is 8 ppm or less.

14. The activated carbon according to claim 11, wherein said heavy metals comprise at least iron, and wherein the iron content is 0.3 ppm or less.

15. The activated carbon according to claim 11, wherein said heavy metals comprise at least zinc, and wherein the zinc content is 0.3 ppm or less.

16. The activated carbon according to claim 11, wherein said heavy metals comprise at least copper, and wherein the copper content is 1 ppm or less.

17. The activated carbon according to claim 11, wherein said alkali metals are sodium and/or potassium.

18. The activated carbon according to claim 11, comprising a silver content of 0.1 ppm or less.

19. The activated carbon according to claim 11, wherein the carbon contents extracted by an extraction treatment using a hydrocarbon solvent, is 0.2 wt % or less.

20. An activated carbon manufacturing method, comprising subjecting an easily graphitizable carbonaceous material to an alkali activation treatment, and then washing the activation treatment product, thus obtained, with an acidic aqueous solution containing an oxidizing agent to give the activated carbon.

21. The activated carbon manufacturing method according to claim 20, wherein an alkali metal hydroxide, used as an activation assistant in the alkali activation treatment, is sodium hydroxide and/or potassium hydroxide.

22. The activated carbon manufacturing method according to claim 20, wherein said acidic aqueous solution is hydrochloric acid.

23. The activated carbon manufacturing method according to claim 20, wherein said oxidizing agent is hydrogen peroxide.

24. An activated carbon manufacturing method, comprising subjecting an easily graphitizable carbonaceous material to an alkali activation treatment, and then washing the activation treatment products thus obtained, with hot water, hot hydrochloric acid and water, in that order, to give the activated carbon.

27. The activated carbon manufacturing method according to claim 24, wherein the alkali metal hydroxides that is used as an activation assistant in the alkali activation treatments is sodium hydroxide and/or potassium hydroxide.

28. The activated carbon manufacturing method according to claim 24, wherein the temperature of said hot water is 30 to 95°

C.

29. The activated carbon manufacturing method according to claim 24, wherein the temperature of said hot hydrochloric acid is 60 to 90°

C.

30. The activated carbon manufacturing method according to claim 24, wherein the concentration of said hot hydrochloric acid is 0.5 to 3 N.

25. An activated carbon manufacturing method, comprising subjecting an easily graphitizable carbonaceous material to an alkali activation treatment, and then washing the activation treatment product, thus obtained, with hot water, carbonate water, hot hydrochloric acid, aqueous ammonia and hot waters in that order, to give the activated carbon.

26. An activated carbon manufacturing method, comprising subjecting an easily graphitizable carbonaceous material to an alkali activation treatment, and then washing the activation treatment product, thus obtained, with hot water, carbonated water, hot hydrochloric acid, aqueous ammonia, hot hydrochloric acid and hot water, in that order, to give the activated carbon.