Electrochemical Copolymerization of Some Pyrimidine-N-Glycosides-Doped Poly(3,4-Ethylenedioxythiophene)/Polypyrrole Electrodes for Enhanced Supercapacitor Performance

Abstract

In this study, high-performance composite electrodes based on poly(3,4-ethylenedioxythiophene) (PEDOT) and polypyrrole (PPy) were successfully synthesized via electrochemical copolymerization in the presence of two distinct pyrimidine-N-glycosides (compounds 1 and 2) on pencil graphite electrodes (PGE). The structural and morphological properties of the prepared electrodes were systematically characterized by x-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, and scanning electron microscopy/energy-dispersive spectroscopy (SEM-EDS) analyses, confirming uniform dopant integration and enhanced crystallinity, especially in PEDOT/PPy/(2)/PGE. Electrochemical evaluations were carried out using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge-discharge (GCD) techniques in a PVA/H21SO4 gel electrolyte. The PEDOT/PPy/(2)/PGE electrode demonstrated the highest electrochemical performance, achieving remarkable specific capacitance of 195.2 F/g, energy density of 45.8 Wh/kg, and power density of 77.4 W/kg. In a symmetric two-electrode configuration, the PEDOT/PPy/(2)/PGE//PEDOT/PPy/(2)/PGE supercapacitor retained specific capacitance of 61.8 F/g at 5 mV/s, and maintained stable energy storage up to 3.7 Wh/kg. The superior capacitive behavior is attributed to the synergistic interaction between the conducting polymer backbone and the pyrimidine-N-glycoside dopant, leading to improved electron/ion transport, enlarged surface area, and optimized microstructure. These results suggest that the pyrimidine-N-glycoside-functionalized conducting polymer composites, in particular with compound 2, hold substantial promise for the development of next-generation electrochemical energy storage devices.