Carbon Nanotube–Manganese oxide nanorods hybrid composites for high-performance supercapacitor materials

Abstract In the present work, multiwall carbon nanotubes (CNTs) were used as a reducing agent for the preparation of CNT-MnO2 nanocomposites by varying the amount of potassium permanganate (KMnO4). The chemical compositions of the as-synthesized materials were analyzed using X-ray diffraction, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy, which showed the formation of MnO2 in the CNT-MnO2 nanocomposites. The electrochemical properties of the CNT-MnO2 nanocomposites were thoroughly investigated through cyclic voltammetry, charge–discharge, and impedance studies. The CNT-MnO2-25 nanocomposites showed the highest specific capacitance of 674 F g–1 at a current density of 2 A g–1; they also displayed an excellent capacitance retention of ∼110 % even after the completion of 5000 continuous charge–discharge cycles at 10 A g–1.