Preparation And Electrochemical Properties Of Co₃O₄ Based Nanocomposite Electrode Materials

With the continuous development of new energy technologies in recent years,supercapacitors(Electrochemical Capacitors,ECs)have become a kind of energy storage devices that have attracted much attention.Because of their high theoretical capacity,high charging efficiency and high coulombic efficiency,they have shown infinite commercial value in new energy vehicles,national defense,transportation and other aspects.Many researchers began to study various types of ECs.However,due to its low energy density,development is restricted.The electrode,as the core component of ECs,has an extremely important impact on its electrochemical performance.Therefore,improving the electrode is the key to the current research.Thesis focuses on Co₃O₄,which is a semiconductor,is often used to make ECs and lithium electrodes,sensors,magnetic material base materials.Now there are many researches on Co₃O₄ and Co₃O₄ based binary metal oxide electrodes,but there are still the following problems:less exposure to active sites;the actual specific capacitance is lower than the theoretical value;less useful cycle life.In order to make up for its shortcomings,thesis considers the combination of Co₃O₄ with NiMoO₄ and CoMoO₄to study and prepare a porous Co₃O₄-based oxide nanomaterials,and studies its structure and electrochemical performance.The research content is mainly divided into the following aspects:(1)Co₃O₄ nanowires were grown by hydrothermal and annealing method using cheap and high conductivity nickel foam as collector.The Co₃O₄ nanowires were physically coated with super phosphorus and polytetrafluoroethylene(PTFE)to prepare working electrode on nickel foam,and SEM,XRD,CV,GCD,EIS and performance analysis were carried out.(2)Co₃O₄@NiMoO₄ three-dimensional core-shell structure was grown by two-step hydrothermal and annealing methods.The working electrode was prepared by the same method as(1),and SEM,XRD,CV,GCD,EIS and performance test were carried out.(3)Co₃O₄@NiMoO₄/CoMoO₄ three-dimensional core-shell structure was grown by two-step hydrothermal and annealing methods,and the working electrode was prepared by the same method as(1).SEM,XRD,XPS,TEM,CV,GCD,EIS and performance analysis were carried out,too.The test results show that at the current density of 1 A·g^-1,the specific capacity of the electrode is 1880.7 F·g^-1,and the attenuation is less after 1000cycles,still maintaining 85%.(4)CV and GCD tests and performance analysis of ECs composed of materials and activated carbon were carried out.