Supercapacitors

They are also known as electrochemical double layer capacitor (EDLC). Supercapacitors are nothing but electrical storage devices but with more capacity. It can store more energy than conventional capacitors and offers appreciable level power density. This category of device is widely used in back-up power sources for electronic devices, in load-leveling, in engine starters and in solar cells. There are three types of supercapacitors-Electrochemical double layer capacitors, Pseudo capacitors and hybrid supercapacitors. In electrochemical double layer capacitors, two carbon based electrodes, an electrolyte and a separator are used. Electrode is made of activated carbon which is cheap and possesses larger surface area. In pseudo capacitors, energy storage is by transfer of charge between electrode and electrolyte Faradaic process. The electrode materials used in pseudo capacitors are conducting polymers and metal oxides. For better performance and storage, hybrid supercapacitors can be used. There are three types of hybrid supercapacitors- composite, asymmetric and battery-type.