Briefly describe the energy storage principle of double-layer capacitors

What is electric double layer capacitor (EDLC)?

Electric double layer capacitor (EDLC) [1, 2] is the electric energy storage system based on charge–discharge process (electrosorption) in an electric double layer on porous electrodes, which are used as memory back-up devices because of their high cycle efficiencies and their long life-cycles. A schematic illustration of EDLC is shown in Fig. 1.

What is the capacitance mechanism of electric double layer capacitors?

Binoy K. Saikia The capacitance mechanism of Electric Double Layer Capacitors is similar to that of dielectric capacitors. In conventional capacitors, energy is stored by the accumulation of charges on two parallel metal electrodes which separated by dielectric medium with a potential difference between them.

How long does it take to charge an electric double layer capacitor?

Whereas charging a rechargeable battery requires several hours, an electric double layer capacitor can be charged in a matter of seconds. Furthermore, the number of charge cycles for a battery is limited, but the electric double layer capacitor in principle has no such limitation.

What are the characteristics of electric double layer capacitors?

The main characteristics of electric double layer capacitors are described below. The surface structure of the activated carbon (pore diameter and volume, specific surface area) has a large influence on capacitance.

What should be the resistance of an electric double layer capacitor?

For large current discharge applications, internal resistance should therefore be kept as low as possible. When an electric double layer capacitor is charged for an extended period of time, the charge current decreases but it does not become zero. Rather it settles at a certain constant value, which is called the leakage current.

Why does a double-layer capacitor have a large electric capacity?

Unlike a normal capacitor, a double-layer capacitor has a large electric capacity because the electric double-layer, that is a layer with the opposite polarity to the electrode is formed around the electrode of the electrolyte. As with normal capacitors, it has very good high-current charge/discharge and repetitive cycle characteristics.