High-performance supercapacitors based on nonfunctionalized MXenes

Abstract

MXenes are a group of two-dimensional materials that have attracted significant research interest worldwide due to their intriguing electrochemical characteristics for use in energy storage applications. However, the conductivity of MXenes and their performance as supercapacitor electrodes can be hindered by surface terminations. This study investigates the capability of non-functionalized MXenes, synthesized via chemical vapor deposition for use as supercapacitor electrodes, presenting a novel approach that explores the potential of these materials in energy storage applications. The synthesized MXenes are used to create supercapacitor electrodes, which are subjected to detailed analysis. The specific areal capacitance (SAC) of these electrodes (48.6 nm thick) is found to be 39.5 mFcm⁻² at a scan rate of 2 mVs⁻¹, equivalent to 928.4 Fg^-1. Further investigation using galvanostatic charge-discharge (GCD) analysis reveals an initial specific gravimetric capacitance (SGC) of 442.6 Fg^-1 at a current density of 0.5 Ag^-1, which progressively decreases to 13.4 Fg^-1 at 10 Ag^-1. Remarkably, the MXene supercapacitors exhibit excellent stability over 10,000 charge-discharge cycles, retaining 85 % of their initial capacitance. These findings contribute to our understanding of MXene-based energy storage devices and pave the way for practical applications in high-performance supercapacitors.