One-step fragmentation of a 2D MXene across the fine 1D MnO2 surface and its supercapacitance

Abstract

Functional materials are being studied for their promising applications. Here, for the first time, a novel approach is highlighted to bring down the morphologies of MXene into small fragments with the aid of finer one-dimensional (1D)/nanorods of MnO₂. This unique grown morphology was characterized by high-resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), X-ray diffraction spectroscopy (XRD) and X-ray photoelectron spectroscopy (XPS). The BET surface area showed an enhancement in surface area from 39 to 201 m² g⁻¹ on incorporating 1D MnO₂ with MXene. Morphological tension as developed between MnO₂ and the MXene surface helped in the considerable improvement of the supercapacitive behaviour of MnO₂. An increase of 92.4% in the capacitive behaviour of MnO₂ was observed with 818.5 F g⁻¹ at 3 A g⁻¹. Electrochemical device characterization was undertaken to achieve a promising energy density of 77.2 W h kg⁻¹ at 1725 W kg⁻¹. Favourable stability retention of 192.3% in a 3-electrode system and stable performance with 80% retention in a 2 electrode system were achieved after 5000 cycles of galvanostatic charge–discharge. The hydrothermal growth process of (1D) MnO₂ is quite effective in bringing MXenes down to fragments, thereby enhancing their overall activity for showcasing one of the best supercapacitive behaviours.