Doping Nanomaterials for Supercapacitors

The intentional insertion of foreign atoms into a crystalline lattice leads to ionizable entities within the material structure, leading to the generation of mobile free carriers, resulting in an induced shift in its Fermi level, significantly improving the material's electrical conductivity, allowing faster and more efficient charge transport of supercapacitor electrodes during charging and discharging cycles. In an electric double-layer capacitor, doping in an electrode material introduces additional Faradaic reactions alongside electric double-layer capacitance, synergistically increasing the overall capacitance of the material. The diverse categories of dopants in nanomaterials for supercapacitor applications exhibit unique features that significantly influence their electrochemical performances. This interplay between the dopant type and electrochemical properties highlights the pivotal role of material selection in developing high-performance supercapacitors. Further, choosing the right doping preparation method and doping concentration is essential for controlling the morphology and configuration of these nanomaterials, as electrochemical properties are closely related to the morphology of the nanomaterial. This chapter discusses the underlying mechanisms and governing principles through which doping is carried out. It also offers valuable insights into various dopant materials across a diverse range of base materials, including carbon-based structures and metal oxides, as well as their performance in supercapacitor applications.