Design of Highly Active Silicene Hybrid Sheets for Electrode Applications in Battery-Type Supercapacitors

Abstract

In this study, silicene nanosheets (SNs) were synthesized using molten salt chemical exfoliation. Polythiophene (PTh) and SNs/PTh nanocomposites were prepared through an in-situ chemical oxidative polymerization method. Raman spectroscopy confirmed the formation of SNs, PTh, and various SNs/PTh nanocomposites at different ratios. X-ray diffraction (XRD) analysis verified the presence of crystalline SNs, the amorphous nature of PTh, and the combination of crystalline SNs with amorphous PTh in the nanocomposites. Field-emission scanning electron microscopy (FESEM) revealed the morphology of silicene sheets and the distribution of PTh granular globes and flakes in the SNs/PTh nanocomposites. Transmission electron microscopy (TEM) showed transparent and reduced-stacking SNs, as well as aggregated PTh flakes and evenly distributed PTh flakes over the SNs surface in the nanocomposites. Electrochemical tests indicated that SNs/PTh nanocomposites exhibited higher specific capacitance, energy density, and stable cycling performance compared to individual SNs and PTh. Cyclic voltammetry (CV) measurements showed that the best performing supercapacitor electrode, SNs/PTh-67 nanocomposite displayed a specific capacitance of 276.25 F/g at a scan rate of 5 mV/s and delivered an energy density of 13.8 Wh/kg. The SNs/PTh-67 nanocomposite also exhibited excellent cycling stability with a capacitance retention of 85.9% after 2000 consecutive charge–discharge cycles at a current density of 4 A/g. This study demonstrates the potential of SNs/PTh-67 nanocomposite as a stable and high-performance electrode material for supercapacitors.