Synthesis of CZTS/RGO composite material as supercapacitor electrode

Abstract In this paper, Cu 2 ZnSnS 4 (CZTS)/reduced graphene oxide (RGO) composite was obtained by a hydrothermal treatment of the mixture of CZTS and graphene oxide (GO). The samples were characterized by means of X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy and scan electron microscopy, thermal gravimetric analysis, and Brunauer–Emmmett–Teller (BET) test. The electrochemical performance of CZTS particles and CZTS/RGO composite used as supercapacitor electrodes was tested for the very first time. The electrochemical measurement demonstrated that the specific capacitance for CZTS/RGO in 3 M KOH aqueous electrolyte was as high as 591 F/g at a current density of 0.25 A/g which was four times larger than that of pure CZTS (138 F/g). Increasing the current density to 1 A/g, the specific capacitance of CZTS/RGO composite was kept as high as 248.5 F/g. After 1000 cycles, the capacity retention was still maintained at 80.6%. It was concluded that the high conductivity and large surface area of RGO resulted in the lower charge transfer and ion diffusion resistance in CZTS/RGO composite, which synergistically enhanced the capacitive performance of composite material.