The fabrication of asymmetry supercapacitor based on MWCNTs/MnO2/PPy composites

The well-designed MWCNTs/MnO2/PPy composites, used as an anode in an asymmetric supercapacitor (ASC), were successfully synthesized via three steps. The scanning electron microscopy (SEM) exhibits that the composites have a special structure which is composed of nanotubes and many particles. To enhance the electrochemical performance of the composites, the redox additive (I-/I-2) with 1 mol L-1 Na2SO4 solution is employed as electrolyte. As expected, cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) tests verify that, in three-electrode system, the specific capacitance can reach 806 Fg(-1) at the current density of 1 A g(-1) with 1 mmol of I-2. At the same time, after assembling an asymmetric supercapacitor with active carbon (AC), the maximum energy density and power density of the device is 92.4 Wh kg(-1) and 761.9 W kg(-1), respectively. The most important thing is that the practical application of MWCNTs/MnO2/PPy composites can be strongly demonstrated by successfully lighting a light-emitting diode. (C) 2019 Elsevier Ltd. All rights reserved.