Electrochemical pseudocapacitors: mechanism, materials, characterization and electrochemical performance

Electrochemical capacitors (ECs) have attracted great attention of scientist for their application in most technology such as electric vehicles (EVs), uninterruptible power supplies (UPS), DC power systems, and mobile devices. Filling the gap between capacitors and batteries, high power, high energy and long lifetime are some of benefits of using ECs. ECs are divided to two parts about charge storage mechanism; EDLC that store charge in electrical double layer and pseudo capacitor that energy storage is due to the faradic process. From the view of active material ECs are divided to four categories; carbon materials, metal oxides, conductive polymers (CPs) and hybrid materials. In recent years hybrid nanocomposite of conductive polymer/metal oxide and conductive polymer/carbon based materials have been given considerable attention due to its mechanical and chemical properties and fast electron transfer kinetics [1-5]. In the presented work, different electrosynthesized metal oxide, ionic liquid, ceramic material and graphene oxide/ conductive polymer as composite materials were electrodeposited on the surface of the working electrode and fundamental physielectrochemical aspects, electrochemical performance were evaluated in an aqueous acidic medium. Surface analysis and different electrochemical methods including galvanostatic charge–discharge (CD) experiments, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were carried out in order to investigate the applicability of the system as a hybrid supercapacitor.