Abstract

Poly (3, 4-ethylenedioxythiophene) (PEDOT)– Manganese Oxide (MnO2) composite electrodes were made to assemble a symmetrical solid-state supercapacitor. The electrode was prepared by different synthetic routes; the first one was obtained by dipping a pulsed polymerized PEDOT film inside a solution mixture of potassium permanganate KMnO4 and manganese sulfate MnSO4, and the second one was obtained by dipping the PEDOT film inside KMnO4, which resulted in a thinner MnO2 layer, and thus better results. The presence of MnO2 was confirmed by the symmetrical stretching vibration of the MnO6 groups and the peak corresponding to Lithium Birenessite, with reference to the relevant literature. The optimum MnO2 thickness was reached by soaking the PEDOT electrode in the MnO2 solution for 10 minutes, reaching a 40°C temperature, which corresponded to the thinnest MnO2 layer. The optimum PEDOT thickness was achieved by adjusting the number of cycles to 20K, resulting in the thickest PEDOT film with the highest conductivity. The supercapacitor exhibited a maximum capacitance of 122.08 mF cm-2 at 10 mVs-1. The ultimate specific energy and power values were 26.19 Wh kg-1 and 6.09 kW kg-1. The supercapacitor device showed a stable electrochemical behavior when subjected to a charge-discharge life test of 1000 consecutive cycles with an average Coulomb efficiency of 94.6%.

Key words: PEDOT; Manganese Oxide; Pseudo-capacitance; Electrochemical Energy Storage; Solid-State Supercapacitors.