Ultracapacitors with high frequency response

Abstract

An electric double layer capacitor (EDLC) is disclosed including: a first electrode including a first current collector and first plurality of carbon nanotubes (CNTs) disposed substantially directly upon the first current collector; a second electrode comprising a second current collector and second plurality of CNTs disposed substantially directly upon the second current collector; and an electrolyte disposed between and in contact with (e.g., wetting) the first and second electrodes. In some embodiments, the EDLC is configured to have a capacitive frequency window comprising about 1 Hz to about 50 Hz.