Working Principle of Supercapacitor


A supercapacitor is a capacitor that possesses a high charge storing capacity. This indicates that the energy density and the capacitance value of a supercapacitor are significantly higher than the normal capacitors. Typically, supercapacitors can have capacitance values ranging from a few mili farads to tens of farads. Typically, the amount of energy that a supercapacitor can store is 10 to 100 times more than the electrolytic capacitors. A supercapacitor is generally preferred in place of batteries because they are able to deliver charge at a comparatively faster rate and they allow quick and simple charging. The surface area of the plates of a supercapacitor is relatively more, while the distance between the two plates is less as compared to that of normal electrolytic capacitors. Supercapacitors are advantageous as they are durable, have a long life span, and do not easily get affected by wear and tear. One can feasibly charge and discharge a supercapacitor again and again without any inconvenience. The supercapacitors possess a low value of resistance, hence they are able to deliver high load currents. The fine build quality of a supercapacitor prohibits it from getting affected by overcharging. Also, the supercapacitors have a low value of impedance and are reliable in nature. The limitations of a supercapacitor include high cost and high self-discharge rate. The linear discharge of voltage prohibits the efficient use of the full energy level possessed by the supercapacitor. Supercapacitors are generally used for industrial applications where a quick charging rate of the battery and high charge holding capacity is desired. For instance, they are widely used to supply power to equipment such as elevators, trains, uninterrupted power supply systems, security alarms, cranes, etc. A supercapacitor is also known as an ultracapacitor or a double layer electrolytic capacitor.

Working Principle of a Supercapacitor

A supercapacitor typically works on the principle of storing electrical energy between two electrostatic double layers that are formed due to the deposition of thin layers of charge on the interface of the electrolyte and the inner side of the capacitor electrode plates.

Working Principle of a Supercapacitor

Construction of a Supercapacitor

The construction of a supercapacitor is quite similar to that of a normal electrolytic capacitor. It consists of two metal electrode plates that are soaked into an electrolyte solution and are separated by a thin insulation layer. The surface area of the conduction plates of supercapacitors is significantly large and the distance between the plates is less as compared to the traditional capacitors. A supercapacitor is an electrochemical device, but it does not make use of chemical reactions to produce electrical energy. The material used to construct the metal plates of a supercapacitor is generally coated with porous materials such as carbon, activated charcoal, etc. The electrolyte material present between the two plates provides the necessary insulation and protection to the device against charge leakage and short circuit. A supercapacitor is capable of storing a huge amount of charge value as the capacitance value of the capacitor is always directly proportional to the surface area of its conduction plates, which in this case is significantly large. Also, the value of capacitance is inversely proportional to the distance between the plates, which in the case of supercapacitors is considerably less as compared to the traditional capacitors.

Working of a Supercapacitor

The capacitors make use of static electricity or electrostatics to store energy. The electrolyte solution present between the two plates of the supercapacitor contains both positively and negatively charged ions. When a voltage is applied across the plates of the supercapacitor, one of the plates tends to develop a positive charge, while the other plate gets negatively charged. This causes the negative ions present in the electrolyte solution to get attracted towards the positively charged plate and the positively charged ions to get attracted towards the negative metal plate. A thin layer of ions gets deposited on the inner side of both plates. This leads to the formation of an electrostatic double layer, which is comparable to a series connection of two capacitors. The distance between the charge layers of both the resultant capacitors is very thin, hence each of them possesses a high value of capacitance. The overall capacitance of the supercapacitor can be calculated by evaluating (C1 x C2)/(C1 + C2).

Add Comment