Patent ID: 7091156

Claim:
An activated carbon suitable for use in electric double layer capacitors, said activated carbon being produced by carbonization of a carbonaceous material consisting essentially of coconut shell, wherein said activated carbon is produced by a process comprising: pulverizing a coconut shell; carbonizing said coconut shell in an inert atmosphere to produce a coconut shell char; and 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 m 2 /g to 2500 m 2 /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 cm 3 /g to 0.15 cm 3 /g, wherein the amount of oxygen contained per g of said activated carbon is 1.8 mg to 8.1 mg, and wherein said activated carbon exhibits a spontaneous potential versus a lithium electrode of 2.85 V to 3.03 V in a non-aqueous electrolytic solution.