Designs,Synthesis Of Nickel-based Composites And The Properties Of Supercapacitors

With the development of technology,people gradually improve the functioning requirements of energy storage devices.Supercapacitors are new energy storage devices with excellent performance.The choice of electrode materials directly determines the energy storage performance of supercapacitors.Therefore,research on electrode materials has become a hotspot in the field of supercapacitors.Nickel hydroxide and its matrix composites are promising electrode materials with the advantages of a larger capacitance,wider material sources,lower price and easy preparation.In order to increase the reaction sites of the electrode material,control the morphology of electrode materials,increase the specific surface area of materials,and the preparation of the excellent performance of nickel-based super capacitor,this paper studied the nickel hydroxide and its matrix composite materials as electrodes in the application of super capacitor,probes into the structure of the nickel base material,the relationship between morphology and the electrochemical properties.The main research contents can be summarized into the following two aspects:1.FeCo₂O₄ nanomaterials were prepared by liquid phase deposition with ferric nitrate and cobalt nitrate as raw materials.FeCo₂O₄-Ni（OH）₂ micronanomaterials were prepared by electrochemical deposition using nickel chloride as nickel source.The morphology,structure,valence and electrochemical properties of the composite were studied.The results show that nickel foam has excellent electrical conductivity and high specific surface area.The composite material has a specific capacitance of 18F·cm^-2 at a constant current of 4 mA·cm^-2.Through the test of 1000 cycle life,60%capacity can still be maintained,which indicates that this material has excellent electrochemical performance and is suitable for the electrode material of supercapacitor.2.Using cobalt nitrate and nickel nitrate as raw materials,NiCo₂O₄-Ni（OH）₂nanoflower-like materials were prepared by hydrothermal method.The morphology,structure and electrochemical properties of the material were studied.The results show that the morphology of the materials can be regulated by adjusting th e proportion of DMSO and the time of hydrothermal treatment,thereby affecting the electrochemical properties of the materials.NiCo₂O₄ nanometer material was synthesized by hydrothermal method,and Ni（OH）₂ was further coated on NiCo₂O₄ nanometer flower surface by electrochemical deposition.NiCo₂O₄-Ni（OH）₂ composite materials with best electrochemical properties were obtained by controlling electrochemical deposition time.The crystal structure,morphology and element distribution of the composites were characterized by X-ray powder diffraction（XRD）,scanning electron microscope（SEM）and elemental analysis.The nickel-based composite material was applied to the supercapacitor.Under the condition of current density of 4 mA·cm^-2,the maximum specific capacitance could reach 18 F·cm^-2 and 20 F·cm^-2,respectively.