Study of Quantum Capacitance of Pure and Functionalized Nb<sub>2</sub>c and Ti<sub>2</sub>c Mxenes for Supercapacitor Applications
Bharti Bharti, Yogesh Kumar, Meenal Gupta, Shatendra Sharma
Abstract
Supercapacitors in combination with renewable energy sources can provide environment friendly and sustainable energy devices. But due to their lower energy density, they are not able to replace batteries for all commercial applications. Their energy density can be increased by using high quantum capacitance electrodes. MXenes have potential to be used for such electrodes. In present work, density of states, band structure and quantum capacitance (QC) of bare and functionalized niobium carbide and titanium carbide MXenes are studied using DFT simulations. The calculated quantum capacitances of Nb 2 C and Ti 2 C show significant values of 324.1 and 246.2 µF/cm 2 respectively. Nb 2 C shows higher value for QC in comparison to Ti 2 C for both positive as well as negative electrodes. These calculations are also performed for functionalized MXenes using =O, -F and –OH as functional group. Functionalization of MXenes with these groups reduces the QC of Nb 2 C and Ti 2 C MXenes at Fermi level.