Exploring the performance of pristine and defective silicene and silicene-like XSi3 (X= Al, B, C, N, P) sheets as supercapacitor electrodes: A density functional theory calculation of quantum capacitance

Abstract

Silicene and silicene-like structures have attracted scientists’ attention because of their novel physical and electronic properties. Recently, they have been studied theoretically as supercapacitor and Li-ion battery electrodes. In this research, the quantum capacitance of pristine and defective silicene and XSi3 silicene-like (X = Al, B, C, N, P) structures calculated using first-principles computations. Our results show that pristine XSi3 sheets have larger quantum capacitance values (cQ = 1500–2000 F/g) in comparison with pristine silicene (cQ = 1200 F/g) and graphene (cQ = 500 F/g). Our partial density of states (PDOS) analysis showed that the origin of large quantum capacitance of XSi3 silicene-like sheets are from 2p and/or 3p orbitals of X and Si atoms. Our data indicated that defects like single vacancy, double vacancy, and Stone−Wales (SW) have not a pronounced effect on quantum capacitance of XSi3 structures.