Patent ID: 7646588

Claim:
A capacitor comprising; a separator; an electrolyte; a pair of polarizable electrodes; and a pair of collecting electrodes, wherein the separator is sandwiched between the polarizable electrodes, the separator and the polarizable electrodes are sandwiched between the collecting electrodes, and each polarizable electrode comprises a carbon nanotube film and is impregnated with the electrolyte, wherein the carbon nanotube film includes: (i) a first carbon nanotube group that is an aggregate of first carbon nanotubes crosslinked to each other to form a network structure; and (ii) a second carbon nanotube group that is an aggregate of second carbon nanotubes having a diameter different from a diameter of the carbon nanotubes in the first carbon nanotube group, wherein the first carbon nanotube group and the second carbon nanotube group are in admixture, the first and second carbon nanotubes are multi-walled carbon nanotubes, ones of the first and second carbon nanotubes have a number-average diameter of from 10 to 50 times of that of the other ones of the first and second carbon nanotubes, and the proportion of ones of the first and second carbon nanotubes, which are larger in diameter, falls in a range from 55% to 70%.