11 - Supercapacitors: a review on electrode materials and models based on conjugated polymers

Abstract

Supercapacitors (SCs) have specific capacitance values from a few farads to a few hundred farads or even more. These high capacitance values are achieved by using suitable electrodes with extremely high surface areas separated by a few nanometers of dielectric materials. The high capacitance has opened applications in various sectors, including the consumer electronics, industrial, space and defense, transportation, and flexible electronics sectors. SCs follow the same basic principle of functioning as capacitors, which store charge on the surface of the electrode within a small span of time. The scientific and technological evolution of capacitors to SCs bridges the energy-power difference between traditional capacitors and fuel cells/batteries. SCs are broadly categorized into electric double layer capacitors and pseudocapacitance SCs. This chapter reviews the different types of SCs, their models, electrode materials, medium and applications. The dependence of a high energy density for SC devices on the electrodes and the maintenance of a high power density are the emphasis of this book chapter. Tabular studies of various electrode materials along with the associated parameters are reported, while highlighting their applications.