Activated carbon for use in electric double layer capacitors
First Claim
1. A method of making an activated carbon, which comprises the steps of:
- a) pulverizing a coconut shell;
b) carbonizing said coconut shell in an inert atmosphere to produce a coconut shell char; and
c) heat-treating said coconut shell char at a temperature ranging from 900°
C. to 1,100°
C. in a steam gas atmosphere containing an inert gas selected from the group consisting of nitrogen, argon, and a combustion exhaust gas, wherein the content of steam in said steam gas atmosphere ranges from 30% by volume to 100% by volume,wherein said activated carbon has a BET specific surface area of 2000 m2/g to 2500 m2/g, and an average pore diameter of 1.95 nm (19.5 Å
) to 2.20 nm (22 Å
),wherein the pore volume of pores having a pore diameter, as calculated according to a Cranston-Inkley method, of 5.0 nm (50 Å
) to 30.0 nm (300 Å
) is 0.05 cm3/g to 0.15 cm3/g.
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Accused Products
Abstract
Activated carbon adapted for electric double layer capacitors is provided, which capacitors can give a large power density per unit volume and which capacitors, even when charge-and-discharge cycle is repeated under a large current or a constant voltage is continuously applied for a long time, undergo less decrease in output density. In particular, the present invention relates to the activated carbon manufactured by carbonization of coconut shell, which has a BET specific surface area of 2000 m2/g to 2500 m2/g, an average pore diameter of 1.95 nm (19.5 Å) to 2.20 nm (22 Å) and a pore volume of pores having a pore diameter calculated according to a Cranston-Inkley method of 5.0 nm (50 Å) to 30.0 nm (300 Å), of 0.05 cm3/g to 0.15 cm3/g.
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Citations
9 Claims
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1. A method of making an activated carbon, which comprises the steps of:
-
a) pulverizing a coconut shell; b) carbonizing said coconut shell in an inert atmosphere to produce a coconut shell char; and c) heat-treating said coconut shell char at a temperature ranging from 900°
C. to 1,100°
C. in a steam gas atmosphere containing an inert gas selected from the group consisting of nitrogen, argon, and a combustion exhaust gas, wherein the content of steam in said steam gas atmosphere ranges from 30% by volume to 100% by volume,wherein said activated carbon has a BET specific surface area of 2000 m2/g to 2500 m2/g, and an average pore diameter of 1.95 nm (19.5 Å
) to 2.20 nm (22 Å
),wherein the pore volume of pores having a pore diameter, as calculated according to a Cranston-Inkley method, of 5.0 nm (50 Å
) to 30.0 nm (300 Å
) is 0.05 cm3/g to 0.15 cm3/g. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification
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- Resources
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Current AssigneeMitsubishi Chemical Corporation (Mitsubishi Chemical Group Corp.), Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
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Original AssigneeMitsubishi Chemical Corporation (Mitsubishi Chemical Group Corp.), Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
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InventorsToki, Kazuyuki, Hirahara, Satoshi, Takeda, Yositaka
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Primary Examiner(s)HENDRICKSON, STUART L
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Application NumberUS11/471,701Publication NumberTime in Patent Office1,259 DaysField of Search502/432, 502/437US Class Current502/432CPC Class CodesC01B 32/324 from waste materials, e.g. ...C01B 32/336 characterised by gaseous ac...H01G 11/24 characterised by structural...H01G 11/34 characterised by carbonisat...H01G 11/38 Carbon pastes or blends; Bi...H01G 11/42 Powders or particles, e.g. ...Y02E 60/13 Energy storage using capaci...Y02T 10/70 Energy storage systems for ...
