High-Performance Supercapacitors Utilising PEDOT Composite Electrodes; Synthesis, Characterisation and Electrochemical Performance Analysis

Abstract The aim of this work was to prepare poly(3,4-ethylenedioxythiophene) (PEDOT) electrodes from an electrolyte containing graphene oxide (GO) and sodium dodecyl sulphate (SDS) (PEDOT/GO/SDS) or poly(4-styrene sulphonate) (PSS) (PEDOT/GO/PSS) solutions. The synthesis was also carried out without GO presence (PEDOT/SDS, PEDOT/PSS). PEDOT and PEDOT/GO were synthesised at glassy carbon support, while PEDOT/GO-R was synthesised at GO support, all were prepared by applying 1.0 V vs. SCE during 300 s. After PEDOT synthesis, the electrode with GO support was additionally polarised at -1.4 V vs. SCE in 0.1 mol dm− 3 KCl solution for 600 s, to obtain reduced graphene oxide (rGO). In this way, PEDOT/GO/SDS-R and PEDOT/GO/PSS-R electrodes were prepared. Prepared electrodes were used to assemble symmetric supercapacitors tested by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The stability of the supercapacitors was determined by charging/discharging at constant current during 1000 cycles, and the specific capacitance (Cs), energy (Ws) and power (Ps) were calculated. The presence of GO in synthesis solution or as support decreased synthesis rate and resulted in a more compact layer with a lower specific capacitance value. However, the successful reduction of GO resulted in a significant improvement of capacitive properties, making this electrode suitable for high-energy applications.