Synthesis and Performance of Tungsten Disulfide/Carbon (WS2/C) Composite as Anode Material
The precursors of an amorphous WS 2 /C composite were synthesized by a simple hydrothermal method using Na 2 WO 4 ·2H 2 O and CH 3 CSNH 2 as raw materials, polyethylene glycol as dispersant, and glucose as the carbon source. The as-synthesized precursors were further annealed at a low temperature in flowing argon to obtain the final materials (WS 2 /C composite). The structure and morphology of the WS 2 /C composite were characterized by x-ray diffraction, x-ray photoelectron spectroscopy, and scanning electron microscopy. The electrochemical properties were tested by galvanostatic charge/discharge testing and alternating current (AC) impedance measurements. The results show that the as-prepared amorphous WS 2 /C composite features both high specific capacity and good cycling performance at room temperature within the potential window from 3.0 V to 0.01 V (versus Li + /Li) at current density of 100 mAg −1 . The achieved initial discharge capacity was 1080 mAhg −1 , and 786 mAhg −1 was retained after 170 cycles. Furthermore, the amorphous WS 2 /C composite exhibited a lower charge/discharge plateau than bare WS 2 , which is more beneficial for use as an anode. The cyclic voltammetry and AC impedance testing further confirmed the change in the plateau and the decrease in the charge transfer resistance in the WS 2 /C composite. The chemical formation process and the electrochemical mechanism of the WS 2 /C composite are also presented. The amorphous WS 2 /C composite can be used as a new anode material for future applications.