Every bite of Supercap: A brief review on construction and enhancement of supercapacitor

Supercapacitor is a potential energy storage device that has been used in various fields like automotive industries, energy harvesting and grid stabilization system due to its unique feature in terms of power density, life cycle, operating temperature range, charge/discharge period, and specific capacitance. Therefore, supercapacitors are used in grid systems to smooth the energy feeding and stabilize the grid system during peak demands. Supercapacitors can provide high power at a short period of time. Correspondingly, supercapacitors are postulated to be the potential replacement for batteries due to their excellent power density which reduces the charging period, longer cycle life than batteries, forgiving even it is overused and is environmentally friendly compared to batteries. However, supercapacitors lack in energy density compared to batteries; thus, it is often used as a short-term energy storage device. Supercapacitors are generally divided into three groups: a) electric double-layer capacitor (EDLC), b) pseudocapacitor, and c) hybrid supercapacitor. These three groups differ in charge storage mechanism, which is closely related to the type and nature of the materials used to design the supercapacitor's electrode. Over and above all, the electrode material is a contributing factor to the supercapacitor's electrochemical performance. Aside from electrode material, electrolyte also influences the electrochemical performance. Hence, it is essential to choose the appropriate electrode and electrolyte according to the desired outcome. To be able to choose, the nature and properties of the materials should be studied. So, in this paper, all three types of supercapacitors are discussed, along with the factors that influence the electrochemical performance. Besides, different electrode materials and electrolytes are included together with an overview of the future scope of supercapacitors.