Surfactant-assisted microwave synthesis of carbon supported MnO2 nanocomposites and their application for electrochemical supercapacitors

Abstract

MnO₂/C nanocomposites have been prepared using a simple onestep microwave heating method by applying different concentrations of cationic surfactant – cetyl trimethylammonium bromide (CTAB). The morphology and composition of the prepared MnO₂/C nanocomposites have been investigated using X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and inductively coupled plasma optical emission spectroscopy (ICP-OES). The electrochemical performance of the prepared nanocomposites has been analysed using cyclic voltammetry. It was found that a high specific capacitance (C_s) of 742 F g⁻¹ at a scan rate of 10 mV s⁻¹ in a 1 M Na₂SO₄ solution has been obtained for the MnO₂/C nanocomposite that has the mass loading of 0.140 mg cm⁻² and has been synthesized in the absence of CTAB. Meanwhile, the application of CTAB allowed the increase in the mass loading of MnO₂ in the nanocomposites. In the presence of CTAB, the highest value of 654 F g⁻¹ at a scan rate of 10 mV s⁻¹ has been obtained for MnO₂/C that has the mass loading of 0.570 mg cm⁻². This result confirmed a good performance of the prepared MnO₂/C nanocomposites as the electrode material for supercapacitors.