Activated carbon for use in electric double layer capacitor and method of producing the same

• US 6,592,838 B1
• Filed: 10/19/2000
• Issued: 07/15/2003
• Est. Priority Date: 10/21/1999
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Nomoto, Susumu, Hirose, Eri, Yoshioka, Kaneharu
• Primary Examiner(s): BOS, STEVEN J
• Application Number:
  US09/692,281
• Time in Patent Office: 999 Days
• Field of Search: 423/445.R, 502/416, 502/427, 361/502
• US Class Current: 423/445.00R
• 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

Activated carbon for use in an electric double layer capacitor which has at least activated carbon, electrolyte solution and a separator, the activated carbon having properties of: the total specific surface area of 1000 m²/g or larger; the pore volume distribution of 400 μl/g or larger for the pores larger than 12 Å and smaller than 40 Å in diameter and of 50 μl/g or larger for the pores larger than 40 Å in diameter; and the total pore volume of 1000 μl/g or smaller.

Claims

1. A method for producing activated carbon for use in an electric double layer capacitor comprising the steps of:

mixing sodium hydroxide and a phenolic resin in the ratio of 1-3 to 1 by weight; and

heating the resulting mixture in a nitrogen atmosphere in the temperature range of 770 to 1000°

C. for 4 hours or less.

2. The method of claim 1 in which heating is carried out between 770°

C. to 850°

C.

3. The method of claim 2 in which heating is carried out for 1.7 hours or less.

4. The method of any of claims 1-3 in which activated carbon has a low temperature electrostatic capacitance of 31 F/g to 44 F/g and a high current electrostatic capacitance of 28 F/g to 51 F/g.

5. The method of any of claims 1-3 in which activated carbon has a low temperature electrostatic capacitance of 40 F/g to 44 F/g and a high current electrostatic capacitance of 32 F/g to 51 F/g.

6. The method of any of claims 1-3 in which activated carbon has a total specific surface area of 1000 m²/g or larger;

a pore volume of 400 μ

l/g or larger for the pores larger than 12 Å

in diameter and smaller than 40 Å

in diameter;

a pore volume of 50 μ

l/g or larger for the pores larger than 40 Å

in diameter; and

a total pore volume of 1000 μ

l/g or less.