Synthesis of graphene/nano-sulphur/polyaniline ternary nanocomposite for high-performance supercapacitor electrodes

Abstract

Graphene/nano-sulphur (S)/polyaniline (PANI) ternary nanocomposite was successfully synthesised and used as an electrode material for supercapacitors. In this process, the aniline was selected to accomplish two functions: In the first place, it served as a reducing agent, promoting the reduction of graphene oxide to graphene, without any additional reducing agent. In the second place, it played an important role in the formation of PANI. S nanoparticles were uniformly decorated on the graphene surface, and PANI covered the graphene/S surface. Furthermore, graphene and PANI prevented polysulphide species diffusion. The products were characterised by field-emission scanning electron microscopy, X-ray diffraction, Fourier-transform infrared spectra, X-ray photoelectron spectroscopy, Raman spectroscopy and electrochemical analysis. Owing to the specific combination of the advantages of graphene, nano-S and PANI, the composite exhibited outstanding electrochemical performance showing a specific capacitance as high as 619 F g−1 at a scan rate of 5 mV s−1 and excellent electrochemical stability with a retention of 77.9% (457 F g−1) of initial capacitance (586.8 F g−1) after 500 cycles at a current density of 1 A g−1.