Conducting polymer based manganese dioxide nanocomposite as supercapacitor

Poly 3,4-ethylenedioxythiophene (PEDOT)- and polyaniline (PANI) nanocomposites were synthesized based on manganese dioxide in the form of Nanorod. Suitability of these composites was studied extensively as an electrode material for symmetric supercapacitor in a widened operating voltage window of 1.2 V. Role of manganese dioxide during reverse microemulsion polymerization in n-hexane medium for PEDOT and aqueous dispersion polymerization for PANI, have been accounted through X-ray photoelectron spectroscopy (XPS). Structural morphology as well as thermal characterization was carried out using XRD, SEM, TEM, IR and TGA. Charge storage mechanism in these nanocomposites have been investigated through cyclic voltammetry (CV) at different scan rates (2–20 mV/s), where intercalation of metal ion during reduction and de-intercalation upon oxidation predominate over surface adsorption and desorption of metal ions into electrode material. Higher specific capacitance for PEDOT–MnO2 (315 F/g) and PANI–MnO2 (221 F/g) are observed in comparison with its constituent MnO2 (158 F/g) where the internal pore volume plays a significant role over the total surface area. AC impedance measurement in the frequency range 10 kHz to 10 mHz with potential amplitude of 5 mV were carried out to ascertain the pseudocapacitance (CFS) arising from the redox reactions over the electrical double layer capacitance (CDL) in the composite materials.