Supercapacitors are electrochemical capacitors that can store unusually high amounts of energy compared to regular capacitors. They consist of two electrodes separated by an ion-permeable membrane and electrolyte. When voltage is applied, ions in the electrolyte form electric double layers on the electrodes, storing energy. Though supercapacitors have advantages like high power rates and longevity, their main disadvantage is lower energy storage per unit weight compared to batteries. They can be used for applications requiring high power or energy recuperation.