Supercapacitors Vs. Batteries

Source: electronicdesign.com

A supercapacitor is a double layer capacitor, it has very high capacitance but low voltage limits. They can store more energy than electolytics. In supercaps, the energy is stored where an electrode interfaces with the electrolyte.

They have a larger area to store charge due to the metal plates coating of a porous material. The plates are immersed in an electrolyte made of both positive and negative ions which are dissolved in a solvent. As the voltage is applied, the two separate charged layers are produced on the surface with a small distance separating the two layers.

The advantage of supercaps are they can be recharged many times and can last decades. After 10 years the capacity maybe reduced by 20% or so. They are capable of producing high current flow and they can be recharged in seconds. They are capable of providing power at very low temperatures.

The disadvantage of supercaps are they have low energy density so they can be a reliable source of continuous power.