A supercapacitor or electrochemical capacitor includes spaced apart electrodes which are separated from each other by a separator made of an electrical insulating material. Each electrode is formed of carbonaceous material and capable of being impregnated with a liquid electrolyte. Metal current collectors are provided on the sides of the electrodes opposite from the separator. The electrodes have holes extending through the electrodes to reduce ionic impedance in order to produce faster charging and discharging of the device.