Enhanced electrochemical and dielectric properties of graphene nanoplatelet/polypyrrole nanocomposites for high-performance sustainable supercapacitors

Graphene nanoplatelet/polypyrrole (GNPLs/PPy) nanocomposites with different loadings of GNPLs (10%–50%) have been successfully prepared by a facile in situ oxidative polymerization and evaluated as advanced electrode materials for supercapacitors. Structural and morphological analyses (Fourier transform infrared [FTIR], X-ray diffraction [XRD], and Scanning Electron Microscopy-Energy-Dispersive X-ray Spectroscopy [SEM–EDX]) confirmed homogeneous incorporation of GNPLs into the PPy matrix, resulting in strong π-π interactions and enhanced interfacial adhesion. Dielectric permittivity explored the improvement in dielectric constant with GNPLs concentration due to interfacial polarization at the surfaces of GNPLs and PPy nanoparticles (NPs). Alternating Current (AC) conductivity spectra presented a significant enhancement in the conductivity value of the GNPLs/PPy nanocomposite compared with PPy NPs, due to simple hopping of charge carriers through the conductive GNPLs network. Electrochemical studies demonstrated a remarkable specific capacitance of 646.61 F g −1 at 0.25 A g −1 for the 50% GNPLs/PPy nanocomposite, with 70% capacitance retention after 1,500 cycles. These findings establish GNPLs/PPy as promising, sustainable, and cost-effective materials for next-generation high-energy-density supercapacitors.