A brief history of supercapacitors

It took 150 years for a concept established in the 1800s to become a technical reality, and a further two decades to make it commercially available. John Miller explains how today's electrochemical capacitors evolved from humble beginnings.

An electrochemical capacitor (EC), often called a Supercapacitor or Ultracapacitor, stores electrical charge in the electric double layer at a surface-electrolyte interface, primarily in high-surface-area carbon. Because of the high surface area and the thinness of the double layer, these devices can have very a high specific and volumetric capacitance. This enables them to combine a . . .