Validating superior electrochemical properties of Ti3C2 MXene for supercapacitor applications through first-principles calculations

Abstract

This work explores the characteristics of two-dimensional (2D) titanium carbide (Ti₃C₂ MXene) and utilizes first-principles study to weigh its potential for supercapacitor applications. Scanning electron microscopy images confirm the layered morphology of the MXene, and energy-dispersive X-ray spectroscopy (EDX) analysis supports the extraction of aluminum from the MAX phase. Fourier-transform infrared (FTIR) spectroscopy confirms the presence of oxygen-based functional groups on the surface of the MXene and X-ray diffraction (XRD) patterns validate its hexagonal crystalline structure. Cyclic voltammetry (CV) analysis reveals the presence of redox peaks, indicating the pseudocapacitive behaviour of the fabricated electrode. Additionally, galvanostatic charge–discharge (GCD) measurements yield a calculated specific capacitance of 370 F g⁻¹. Electrochemical impedance spectroscopy (EIS) substantiates the low impedance resulting from the layered structure via the adequate adsorption/desorption of cations. The utilization of first-principles density functional theory (DFT) calculations reveals the merging of conduction and valence bands, signifying effective conductivity. Both the total and partial density of states cross the Fermi level, indicating a highly efficient charge mobility process. The combination of prominent surface redox reactions and excellent conductivity contributes to the superior specific capacitance of the fabricated electrode. Overall, these results highlight the excellent electrochemical properties of the Ti₃C₂ MXene electrode, declaring it as a promising candidate for supercapacitor applications.