Electrochemical study on an activated carbon cloth modified by cyclic voltammetry with polypyrrole/anthraquinone sulfonate and reduced graphene oxide as electrode for energy storage

Abstract

This work describes a two-step procedure for the electrochemical coating of reduced graphene oxide (RGO) and polypyrrole anthraquinone sulfonate (PPyAQS) onto an activated carbon cloth (ACC) by cyclic voltammetry (CV). The textile samples were characterized by CV, electrochemical impedance spectroscopy (EIS) and galvanostatic charge-discharge measurements using a sandwich-type (electrode/separator/electrode) cell designed to operate in three or two-electrode configurations. The presence of RGO onto the ACC surface optimized the electrosynthesis of PPyAQS and reinforced the stability of the polymer with the number of charge/discharge cycles. A retention capacity of 90% after 100 charge-discharge cycles together with an energy density of 7.8 × 10−4 W h cm−2 at a power density of 1.8 × 10−3 W cm−2 were obtained for the ACC/RGO/PPyAQS sample. The analyses by field emission scanning electron microscopy (FESEM) showed the RGO veils-like and PPyAQS glomerular structures covering the ACC-fibers. The Fourier transform infrared spectroscopy (FTIR) analyses not only detected the presence of PPy and AQS, but also, the changes in the molecular structure of PPyAQS, depending on its oxidation state, as consequence of the redox reactions occurred in the charge/discharge processes in the two-electrode cell.