Hydrothermal synthesis of VS₄/CNTs composite with petal-shape structures performing a high specific capacity in a...

Vanadium sulfide (VS₄) is recognized as a good anode material for energy storage devices because of its chain-like structure and high content of sulfur. Herein, the patronite VS₄ anchored on carbon nanocubes (denoted as VS₄/CNTs) with a petal-shape structure consisting of nanolayers is successfully prepared through a one-step hydrothermal reaction. The influence of the optimal ratio of VS₄ and CNTs on the electrochemical properties of VS₄/CNTs composite is studied by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS). The addition of CNTs increases the conductivity and relieves the volume expansion/contraction, resulting excellent electrochemical properties of VS₄/CNTs. In the potential window of -1.4 V to 1.4 V, the VS₄/CNTs composite electrode delivers an outstanding specific capacitance of 330 F g^-1 (924 C g^-1) at 1 A g^-1, which is much higher than that of VS₂ with 105 F g^-1 (294 C g^-1). The VS₄/CNTs symmetric supercapacitor (SSC) device exhibits the areal capacitance as high as 676 mF cm^-2 (1488 mC cm^-2) at 0.5 mA cm^-2, and the energy density of 4.55 W h m^-2 (51.2 W h kg^-1) at the power density of 2.75 W m^-2 (30.95 W kg^-1) within a large voltage up to 2.2 V. All the results confirm that VS₄/CNTs composite with petal-shape structures is a promising material for high-performance energy storage devices.