Design of supercapacitor electrodes constructed with silicene-polythiophene nanocomposites

Abstract

In this study silicene nanosheets (SNs) were prepared by molten salt chemical exfoliation, and polythiophene (PTh) and SNs/PTh nanocomposites were prepared via in-situ chemical oxidative polymerisation method. Raman spectroscopy confirmed the formation of SNs, PTh, and a series of SNs/PTh nanocomposites in three different ratios. XRD confirmed the formation of crystalline SNs, the amorphous nature of PTh, and crystalline SNs and amorphous PTh in the nanocomposites. FESEM revealed corrugated sheets of silicene, aggregated PTh with granular globes and flakes, in the case of SNs/PTh nanocomposites, PTh granular globes and flakes are fairly dispersed over the surface of the SNs. TEM showed almost transparent and reduced-stacking of SNs, aggregated PTh flakes and SNs/PTh nanocomposites exhibited fairly and even PTh flakes over SNs surface. The electrochemical results showed that SNs/PTh nanocomposites exhibit 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, attained a specific capacitance of 276.25 F/g at a scan rate of5 mV/s and delivered energy density of 13.8 Wh/kg. SNs/PTh-67 nanocomposite also exhibited excellent cycling stability with capacitance retention of 85.9% of its initial capacitance after 2000 consecutive charge-discharge cycles at a current density of 4 A/g. This study provides the first insight into the feasibility of using SNs/PTh-67 nanocomposite as a stable and high-performance electrode material for supercapacitors.