Forms of Functionalized Carbon-Based Nanomaterials, Synthesis, Classifications, and Their Electrochemical Activities for Supercapacitors

Carbon-based nanomaterials such as carbon quantum dots (CQDs), carbon nanotubes (CNTs), activated carbon, 2D graphene, graphene oxide (GO), graphitic carbon nitride, activated carbon, micro and meso porous carbon materials, and MXenes have captivated the interest of researchers in the field of electrochemical-driven energy storage systems due to their intriguing physicochemical properties including porous architecture, high specific surface area, good electrical and ionic/electrical conductivity, chemical stability along with outstanding availability of the electroactive sites for improved diffusion and mass transport of electrolyte ions. Carbon-based materials store charges via the establishment of electrical double-layers (EDLs) at the interface of electrode/electrolyte system. When these carbon-based materials are functionalized with metal nanoparticles, metal oxide, metal chalcogenides, multiple hetero-atoms, various surface functional groups and conducting polymers, it leads to the manifestation of the faradic charge transfer process known as pseudo-capacitance in addition to the improved capacitance emerged due to the EDL in the system. Thereby, the electrochemical properties of these carbon-based systems are improved by many folds via functionalization. Considering such a scenario, this book chapter sheds light into the various types of carbon-based materials, their synthesis methods, functionalization strategies using other material systems, and their electrochemical performance toward supercapacitor applications.