Manganese Dioxide-polypyrrole Carbon Preparation And Properties As Electrode Material Of Supercapacitor

Supercapacitor has a high power density, energy density and capacitance values, even a short charging time and a long cycle life, it is a promising energy storage device. Polypyrrole（polypyrrole, PPy）, as a conductive polymer material, it has a simple preparation, environmentally friendly, doping reversible, and a high conductivity, has received widespread attention as electrode materials of supercapacitors. Manganese dioxide electrode material is a hot topic in recent years, it is a abundant materials with a low cost, a high surface area, a good electrochemical performance, and little pollution. This paper is a combination of these two materials to prepare a excellent performance of electrode material.Preparing PPyC material with a simple chemical synthesis method in this paper, Selecting the best dosage of activated carbon,the optimal dosageof Na2S2O8 and pyrrole monomer, to prepare PPyC material with the great performance. Using cyclic voltammetry, current charge-discharge, Cycle performance method and AC impedance test methods to evaluate its electrochemical properties. The results showed that when the molecular mass ratio of the activated carbon and pyrrole monomers and Na2S2O8 is1: 3.46: 1.73,the electrochemical properties of PPyC is best, capacitance can be reached 125.8 F×g-1.Preparing new composite MnO₂-PPyC with Microwave-assisted method. By changing the reaction temperature, amount of PPyC to prepare different MnO₂-PPyC materials, and the optimal synthesis conditions of MnO₂-PPyC are:under microwave reaction conditions, reactants are 20 ml 0.3 M of MnCl2 solution, 20 ml 0.2 M of KMnO4 solution and the mass of PPyC is 0.05 g; controlling the temperature microwave reactor is 45℃, time is 20 min. That is, when the mass ratio of KMnO4, MnCl2 and PPyC is 12: 24: 1, obtaining the optimal performance of the MnO₂-PPyC-b composite materials, the specific capacitance can be reached 375 F×g-1, after 400 cycles of charge/discharge capacitance remaining is 347 F×g-1.SEM and TEM results show that the MnO₂-PPyC prepared is made up of many flower-like structure composed of thin films, wherein the flower-like structureMnO₂-PPyC-b is more uniform and thinner sheet membranes. The EIS of MnO₂-PPyC-a, MnO₂-PPyC-b, and MnO₂-PPyC-c three materials shows that MnO₂-PPyC-b has a minimum charge transfer resistance, indicating that MnO₂-PPyC-b material is more conducive to electronic transmissions than MnO₂-PPyC-a and MnO₂-PPyC-c. The results show that MnO₂-PPyC-b has excellent reversibility and capacitive as supercapacitor electrode material.