One-pot construction of 3-D graphene nanosheets/Ni3S2 nanoparticles composite for high-performance supercapacitors

Newly three-dimensional graphene nanosheets/transition metal sulfide nanoparticles (i.e. 3-DGNs/Ni3S2 NPs) composite was synthesized by an efficient quasi chemical vapor deposition (Q-CVD) technique in one-pot high temperature growth process. The as-prepared composite materials were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and X-ray photoelectric spectroscopy. The supercapacitive performances of electrodes were evaluated by cyclic voltammetry charging, discharging and electrochemical impedance spectroscopy. The 3-D GNs/Ni3S2 NPs composite synthesized by the Q-CVD technique possesses favourable three-dimensional porous network of graphene and reasonable arrangement of Ni3S2 NPs on the surface of graphene nanosheets. As a promising supercapacitor electrode, a relatively high specific capacitance of 652.5 F g(-1) at current density of 1 A g(-1) in 1 mol L-1 KOH aqueous solution, along with good cycling stability (with a 93% retention rate after 2000 cycles) were demonstrated for the 3-D GNs/Ni3S2 NPs composite electrode. In addition, excellent electrochemical performances were also demonstrated for the asymmetric supercapacitor by using 3-D GNs/Ni3S2 NPs as the cathode and 3-D GNs as the anode. (C) 2017 Elsevier Ltd. All rights reserved.