Synthesis And Performance Of Nickel Based Composite For Supercapacitor

As the depletion of fossil energy and the growing environmental problems, green renewable and alternative energy sources are demanded urgently. Supercapacitor is known as the many advantages than conventional batteries, including fast charge capacity, long cycle life, and high power density. Supercapacitor presents better application outlook in portable equipment, electric power, data storage system memory. Supercapacitor is mainly composed of collector, separator, electrode materials and electrolyte, in which the electrode material plays an important role. The electrode materials not only determine the kind of supercapacitor but also have an importantly impact on the electrochemical performances of supercapacitor. To enhance the capability of the active material, different morphology and structur was designed. On the other hand, because of synergistic effects, compositing is an alternative way to improve the supercapacitor behaviors of single active materials. In this paper, three-dimensional redox grapheme-Ag/NF composite, flower-like Ni3S2-Co9S8 electrode materials and nanorods Ni3S2-MoS2 composite have been prepared using dry immersion method and one-step solvothermal way,respectively, and nickel foam was used as substrate. What’s more, electrochemical properties have been characterized and researched systmatic systematically. The main results are summarized as follows:1. Graphite oxide was prepared by a modified Hummer method and three-dimensional redox grapheme-Ag/NF composite was prepared by dry immersion method. The material crystalline phase, morphology and composition were characterized and electrochemical properties of the material were analyzed. The results showed that redox graphene-Ag/NF was a porous structure in which the diameter of Ag is 200 nm. At the current density of 5 mA/cm2, the specific capacitance was estimated as 1.59 F/cm2. The material also had a retention rate of 70% of its initial capacitance after 1000 cycles and shows good cycle performance.2. In this work, a facile solvothermal route was employed in preparing flower-like Ni3S2-Co9S8 on Ni substrate. The material crystalline phase, morphology and composition were characterized and electrochemical properties of the material were analyzed. The cyclic voltammetry(CV), galvanostatic charge-discharge(GCD) and electrochemical impedance spectroscopy(EIS) were used to analyze the electrochemical performance of the composite. The flower-like Ni3S2-Co9S8 demonstrated a good specific capacitance of 5.37 F/cm2 at a current density of 5 mA/cm2. The specific capacitance could retain about 92.0 % of its initial capacitance after 1000 cycles. The experimental results suggested the composite of Ni3S2-Co9S8 grown on Ni substrate has excellent cycle performance.3. A general solvothermal route was employed in producing nanorods Ni3S2-MoS2 on Ni substrate. X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS) and Scanning electron microscopy(SEM) were used to characterize structure and morphoiogy of the composite. The electrochemical properties of the as prepared Ni3S2-MoS2 composite when the C16H33(CH3)3NBr is 0.365 g suggested a maximum specific capacitance of 10.75 F/cm2 was achieved for the composite at current density of 5 mA/cm2. The capacitance could retain about 75.8 % after 1000 cycles.