Introduction to supercapacitors

Faster economic developments and a growing population need clean and renewable energy sources and sophisticated energy storage technologies such as batteries and supercapacitors. For recent electric vehicle development, energy storage devices with high energy and power density and great cyclic life are required. Despite the battery's high energy density, its low power density and short cyclic life prompt research into other technologies, such as supercapacitors. Due to their desired qualities, such as high power density, quick charge-discharge, a wider working temperature range, and improved cyclic life, supercapacitors have drawn a lot of research interest from the scientific community. Essentially, supercapacitors are divided into two charge storage mechanisms: electric double-layer capacitors (EDLCs) consisting of pure electrostatic and non-Faradaic processes, and pseudocapacitors consist of the Faradaic method, which involves reversible redox reactions. The EDLC electrodes are made of carbon-based materials, whereas the pseudocapacitor electrodes are made of redox-active materials. A hybrid supercapacitor, which combines both types of charge storage methods is said to boost performance even further. In this chapter, the various components of the supercapacitor and their functions have been briefly discussed. The charge storage methods of supercapacitors have been thoroughly investigated.