The Preparation And Capacitive Property Research Based On Nickel Composite Material

The supercapacitor is a new energy storage device,because it has good capacitance characteristics and has been applied in many fields.Among them,the quality of electrode materials play an important role on the performance.We load electrode active material on nickel foam to enhance the capacitive performance which is based on three-dimensional network structure and the excellent property of nickel foam.Such good capacitive performance can attributable to the following two points:First,nickel foam has many microspores and winding channels which increase the specific surface area of the materials in certain degree.And it is also beneficially for transferring.Second,the growth in the substrate materials is able to contact with current collector directly.It has advantage to occur electronic transmission,thus,we can enhance the electrochemical reaction degree of materials and magnify the utilization of active substance.In this paper,hydrothermal method employs autoclave as a reactor for the chemical reaction in airtight container.On the one hand,this method can avoid volatile components volatilization to improve the purity of reaction product and protect the environment.On the other hand,the reaction medium is aqueous solution which can accomplish the particulate construct from the atomic to molecular level.Compared with other methods,hydrothermal method needs shorter reaction time,it also has a series of advantages such as more homogeneous product size,better dispersibility and easier to control process conditions.Therefore,the present paper proposes hydrothermal method to prepare different super capacitor electrode active materials.And we regard this nickel foam loaded electrode active material as the electrode.We have done a series of electrochemical tests and the works are as follows:In chapter one,the introductory part,it expound the development,principle and significance of super capacitor.Equally,it summarizes the characteristics of various electrode materials so that guide the selected topic ideas and research content of this paper.Chapter two has prepared nickel-manganese hydroxide material and nickel-manganese hydroxide material containing surfactant CTAB which contribute to improve its electrochemical activity.After fourier transform infrared spectroscopy,X-ray diffraction,field emission scanning electron microscopy,transmission electron microscope,cyclic voltammetry,thermogravimetric analysis,charge-discharge cycles stability test and electrochemical impedance spectroscopy,specific capacitance of this material is 1162 F/g when current density is 0.5 A/g.In addition,specific capacitance value still reached nearly 77% after 500 cycles circulation charge and discharge.Chapter three has prepared nickel tungsten tetraoxide and the composite of reduced graphene oxide and nickel tungsten tetraoxide by hydrothermal method and characterized by fourier transform infrared spectroscopy,X-ray diffraction,thermogravimetric analysis,field emission scanning electron microscopy and transmission electron microscope.The materials is test by cyclic voltammetry,charge-discharge cycles stability and electrochemical impedance spectroscopy in KOH electrolyte three-electrode system,the result shows specific capacitance of the composite material reached 622 F/g when current density is 0.5 A/g.After 500 cycles circulation charge and discharge,the specific capacitance value still reached more than 80%.Chapter four studies the main content of the paper,discussed the prospect of research and development of super capacitor electrode material.