Preparation And Energy Storage Of Zinc Cobaltate-based And Polyaniline-based Composites

Recently,various countries have paid increasing attention to environmental and energy issues,such as the comprehensive waste sorting and widespread use of electric vehicles.Therefore,the energy storage,which are environment-friendly and efficient,has become a hot research direction at home and abroad.As a new kind of energy storage system,the supercapacitor has the characteristics of high power density,stable cycle performance and good adaptability to the working environment.The core of supercapacitor is the electrode material that have the excellent electrochemical performance.However,the development of supercapacitor electrode materials has encountered many problems,such as low specific capacity,which cannot meet the requirements of practical applications.Therefore,it is of great practical significance to develop electrode materials with high yield,high efficiency and stable electrochemical performance.In this paper,zinc cobaltate and polyaniline are used as the research objects,and the works involve the microstructure design,synthesis method improvement and electrochemical performance optimization of each of material.The characteristics of the material are analyzed by a series of characterization methods.These works provide some experiences and references for the synthesis and optimization of electrochemical performance of zinc cobaltate-based and polyaniline-based composites.?1?The ZnCo₂O₄@MnCo₂O₄ heterojunction nanosheet composite electrode material is prepared by two-step hydrothermal methods.In the first step,the ZnCo₂O₄substrate material is synthesis by hydrothermal.The second step is to synthesize MnCo₂O₄ nanosheets on ZnCo₂O₄ via the same way.Then the electrochemical properties of ZnCo₂O₄@MnCo₂O₄ is discussed,accroding to the charge and discharge curve,the specific capacity is 254 F/g at 1 A/g.In addition to this,a supercapacitor is assembled with ZnCo₂O₄@MnCo₂O₄ positive electrode and activated carbon negative,and the supercapacitor has an energy density of 19.5 Wh/kg at a power density of 750 W/kg,and after circulating 2000 times at a current density of 1 A/g,the specific capacitance remained at about 98.5%.?2?The electrochemical deposition method is used to grow Ni₃S₂ on flexible carbon cloth fibers to obtain CF/Ni₃S₂,and then a layer of polyaniline is polymerized in situ on Ni₃S₂/CF to obtain the final smaple?CF/Ni₃S₂@PANI?,PANI has good environmental stability,which can protect Ni₃S₂ from corrosion by electrolyte,and the transition metal Ni is coordinated with the N of PANI,which can provide fast channel for electron transmission.?3?A high specific surface area carbon nanocomposite which carring abundant mesopores is prepared as a cathode of a lithium-ion capacitor.The PANI array is grown by proton doping on the surface of the graphene,and then carbonized in an argon atmosphere by a tube furnace.At last,further activated using KOH to prepare a carbon nanomaterial with an abundant pores structure.The specific surface area of up to 2701m²/g.And after 10000 cycles at 5 A/g,the capacity retention rate is 93.4%.When the current density is increased to 20 A/g,the capacity is only dropped from 144.68 F/g to98.7 F/g.