Synergistic effects of liquid phase exfoliated molybdenum based 2D nanosheets and MWCNTs for high performance supercapacitors†

Abstract

This work investigates the application of liquid phase exfoliated Mo-based transition metal dichalcogenide (TMDC) two-dimensional (2D) nanosheets integrated with multi-walled carbon nanotubes (MWCNTs) as a novel electrode material for high-performance supercapacitors. The structural, functional, and morphological analyses were performed by XRD, FESEM, XPS, and Raman spectroscopy, which augmented the successful formation of TMDC nanosheets and their nanocomposites with MWCNTs. Structural and morphological characterization studies revealed the successful synthesis of the 2D nanosheets and their intimate integration with the MWCNTs, forming a porous network. Raman spectra confirmed the presence of vibrational bands for TMDC nanosheets (A_1g and E_2g) and their nanocomposites with MWCNTs (D and G bands). The optical characterisation studies (UV and PL) confirmed the exfoliation of TMDC nanosheets with band gaps of 1.87 eV and 1.67 eV for MoS₂ and MoSe₂, respectively. From the electrochemical characterisation studies, the values of specific capacitance were found to be 3338.29 F g⁻¹ and 2776.59 F g⁻¹ for MoS₂/MWCNT and MoSe₂/MWCNT electrodes with energy densities of 102.42 W h kg⁻¹ and 85.18 W h kg⁻¹, respectively. These nanocomposites retained 84% of the initial specific capacitance over 4000 repeated charge/discharge cycles. These nanocomposites may be used as potential materials for the fabrication of next generation devices for energy storage.