Supercapacitor

 

What are supercapacitors? Supercapacitors are electronic devices which are used to store extremely large amounts of electrical charge. They are also known as double-layer capacitors or ultracapacitors. Instead of using a conventional dielectric, supercapacitors use two mechanisms to store electrical energy: double-layer capacitance and pseudocapacitance. Double layer capacitance is electrostatic in origin, while pseudocapacitance is electrochemical, which means that supercapacitors combine the workings of normal capacitors with the workings of an ordinary battery. Capacitances achieved using this technology can be as high as 12000 F. In comparison, the self-capacitance of the entire planet Earth is only about 710 µF, more than 15 million times less than the capacitance of a supercapacitor. While an ordinary electrostatic capacitor may have a high maximum operating voltage, the typical maximum charge voltage of a supercapacitor lies between 2.5 and 2.7 volts. Supercapacitors are polar devices, meaning they have to be connected to the circuit the right way, just like electrolyte capacitors. The electrical properties of these devices, especially their fast charge and discharge times, are very interesting for some applications, where supercapacitors may completely replace batteries. Supercapacitor definition A supercapacitor is a specially designed capacitor which has a very large capacitance. Supercapacitors combine the properties of capacitors and batteries into one device. Characteristics Charge time Supercapacitors have charge and discharge times comparable to those of ordinary capacitors. It is possible to achieve high charge and discharge currents due to their low internal resistance. Batteries usually take up to several hours to reach a fully charged state – a good example is a cell phone battery, while supercapacitors can be brought to the same charge state in less than two minutes. Specific power The specific power of a battery or supercapacitor is a measure used to compare different technologies in terms of maximum power output [… read more]