Hydrothermal method of rGO/Mo_0.7Co_0.3S₂ nanocomposites for high-performance supercapacitor electrodes

Graphene oxide (rGO) has become a leader in supercapacitors with a wide specific surface area (SSA) (2630 m²/g), high electrical conductivity and chemical stability, and excellent mechanical, thermal and optical properties. However, rGO itself has poor electrical conductivity, so in this paper, rGO is combined with Mo_0.7Co_0.3S₂ to improve its performance. This paper was successfully synthesized different mass ratios of rGO and Mo_0.7Co_0.3S₂ by a simple hydrothermal method. The microstructure was characterized by XRD, SEM, HRTEM, EDS. The electrode is made by using foamed nickel as the substrate, polyvinylidene chlorofluoride as the binder, and N-methyl pyrrolidone as the auxiliary agent. The electrochemical performance was tested on a three-electrode electrochemical workstation with KOH as the electrolyte. The experimental results show that all samples exhibit hexagonal system structure with good crystallization, the morphologies are flower-like microsphere shape with a certain degree of agglomeration. The surface of Mo_0.7Co_0.3S₂ nanoparticles is wrapped by a layer of rGO like yarn. rGO/Mo_0.7Co_0.3S₂ nanocomposite exhibits pseudo-capacitance behavior and excellent electrochemical performance, especially the Mo_0.7Co_0.3S₂ electrode (30wt% rGO content) exhibits the largest specific capacitance and smallest impedance, and the Mo_0.7Co_0.3S₂ electrode (30wt% rGO content) electrode reduced from 1377.00 F·g⁻¹ to 1307.87 F·g⁻¹ after 3000 cycles at a current density of 5 A·g⁻¹, the coulombic efficiency is 95%, which may be due to the Coupling effect between Mo_0.7Co_0.3S₂ and rGO.