Ultracapacitor, Supercapacitor, Gold Capacitor or EDLC ( Electric Double Layer Capacitor) as they are also called, look very much like batteries. They have double layer construction consisting of two carbon electrodes immersed in an organic electrolyte. See below:

During charging, the electrically charged ions in the electrolyte migrate towards electrodes of pposite polarilty due to the electric field between the charged elect-rodes created by the applied voltage. Thus two separate charged layers areproduced. Although similar to a battery, the double layer capacitor depends onelectrostatic action. Since no chemical action is involved the effect is easily reversible and typical cycle life is hundreds of thousands of cycles.

Main Features:
High power avaliable and high power density
Very Fast Charge and Discharge. Can be charge and discharge in seconds
Long cycle life of more than 500,000 cycles at 100% DOD
No chemical actions
Low impedance
Low current leakage
Green Energy