ABSTRACT
The invention of double-layer charge capacitance in the form of supercapacitors brought a significant advancement in the field of charge storage. The progress from electrostatic capacitor, electrolytic capacitor to supercapacitor not only contributed to a significant knowledge in the field of energy storage but also opened wide development avenues. The prospective applications from micron scale to further lowering dimensions of an energy-storage system are possible through the novel charge-storage mechanisms and its advancements. Therefore, it is important to understand the developments that have taken place to progress the field and prospective future advancements. This chapter describes the fundamentals of energy storage in different systems like electrostatic, electrolytic, and electrochemical capacitors. The mechanism of double-charge layer and pseudocapacitance is described by differentiating supercapacitor types. The critical role of various electrolytes and planar microsupercapacitors for on-chip fabrication is discussed in detail.
