Chapter 4 - Theoretical insight for supercapacitors based on 2D materials from DFT simulations

Abstract

Due to the increase in energy demands and reduction in conventional energy sources, it is important to design efficient energy storage devices with higher energy density and power density. There has been notable progress in the design of supercapacitors using advanced 2D materials and their hybrids. Theoretical simulations and insights can provide key design aspects in terms of favorable electronic properties, diffusion energy barrier of electrolytic ions, quantum capacitance, voltage induced due to movement of the charge carrier, as well as bonding and charge transfer for hybrid structures. In this chapter, we will discuss the theoretical insight for the design of 2D material-based supercapacitors as obtained using Density Functional Theory (DFT) simulations. DFT has helped to understand and analyze the structural properties like lattice parameters, bond length, forces involved, energy, and the electronic properties like band structure, density of states, charge transfer, and other information which can influence the charge storage performance. Interpreting these parameters can help to understand how to control the supercapacitance performance in these systems and also the mechanisms to enhance the same by doping, defects, or formation of hybrid structures. This chapter provides an overview of DFT simulations and highlights some of the theoretical parameters which play vital role in fabricating efficient supercapacitor devices with the example from various fascinating 2D materials.