A hierarchically designed ternary nanocomposite of PEDOT:Grp-MnO2 was synthesized as an electrode material for high performance supercapacitors. The binary composite of MnO2 nanoparticles decorated over graphene sheets (Grp-MnO2) were synthesized using a facile, one pot solvothermal method. Further, encapsulation of the binary composite was performed by wrapping with the conductive polymer layers of PEDOT. Structural morphology and oxidation states of Mangnese of the nanocomposite were studied using XRD, TEM, Raman spectroscopy and XPS. Supercapacitive behaviour of the nanocomposites was tested by using them as electrodes for electrochemical studies like cyclic voltammetry and charge discharge. Highest specific capacitance value was found to be 213 Fg(-1) for the PEDOT:Grp-MnO2 (with the ratio of 1:3) with improved energy and power densities. AC impedance measurement was carried out to ascertain the pseudocapacitance arising from the redox reactions over the electrical double layer capacitance (EDLC) in the composite materials. (C) 2017 Elsevier Ltd. All rights reserved.