What Is the Difference Between Capacitor and Supercapacitor?

Capacitors and supercapacitors are passive components that store energy in the form of an electrostatic field. Although the function of both is to store energy, there are some important differences between them.

Capacitor

A capacitor is a two-terminal passive electronic component that stores electrical energy between its metal plates. The capacitor consists of two metal plates (electrodes as anode and cathode) separated by a dielectric insulator.

When a source voltage is applied to the two terminals of a capacitor, current wants to flow through the insulating material, but the material opposes the electron flow. When the voltage at the capacitor terminal is equal to the applied voltage, the insulating medium still resists the flow of electrons. This resistance creates an effect to store energy in the form of an electrostatic field.

Supercapacitor

Also known as a double-layer capacitor or ultracapacitor, the supercapacitor is made of electrodes, each coated with activated carbon. In the supercapacitor, a special separator is used instead of the dielectric material used in conventional capacitors. The separator is an ion-permeable membrane, such as graphene, that insulates and exchanges electrolyte ions between electrodes.

Supercapacitors have a high capacity and can charge very quickly. This allows supercapacitors to be used like a battery. Supercapacitors can store more charge than regular capacitors and provide energy much faster than a battery.

Supercapacitors have high energy storage capacity and long life cycles. Supercapacitors have a very fast charging and discharging speed and can provide high load currents.

Supercapacitors are more expensive than conventional capacitors.

Capacitors are used to smooth the output of the power supply, perform functions such as power factor corrections, frequency filters, coupling and decoupling of signals.

Supercapacitors, on the other hand, are widely used in electric screwdrivers, LED flashlights of digital cameras, computers and similar electronic devices to balance the power supply, which are required to be charged within a few minutes.

The batteries used in traditional UPS (Uninterruptible Power Supply) systems are gradually being replaced by supercapacitors. Although supercapacitors are ideal for short-term power needs, it may still be best to prefer batteries if long-term energy needs are needed.