Study On Electrochemical Properties Of Graphene Composite Manganese Oxide Materials

With the growth of the population on the earth and the increase in energy demand,the energy that was commonly used before can not meet the needs of human beings.Super capacitor has high power density,long cycle life and wide application range,which can reduce the cost of maintenance and repair in the process of practical application.Super capacitor is not only new environmental protection but also low cost,so it will have a good development space.Graphene has unique lamellar crystal structure.It has a large theoretical specific surface area?2630m²/g?,excellent conductivity(Graphene has an electron mobility of15000cm²·V^-1·s^-1),high specific capacitance?550F/g?.It is an excellent electrode material.Studies have found that using some metal oxides as electrode materials,they will undergo redox reactions during the charge and discharge process,which can provide higher energy density,so these types of metal oxides are also ideal electrode materials for supercapacitors.Because graphene and metal oxide have different energy storage mechanism and different advantages and disadvantages,graphene and metal oxide often complement each other in the process of energy storage,avoiding their disadvantages and exerting their advantages.Therefore,this paper mainly studies the electrochemical properties of graphene/MnO₂ complexes.This paper focuses on this issue from the following three aspects of research work,research work mainly involve:?1?Preparation of graphene.The graphite structure of common graphite powder is destroyed through modified Hummers method.Go was obtained by modifying a large number of groups on the surface of graphite sheet.GO has a regular hierarchical structure,and a large number of oxygen-containing groups make it well dispersed in polar solvents.Copper foil as a catalyst to decompose methane to produce carbon,double and multiple layers of graphene were prepared on silicon wafers by CVD method.We successfully prepared monolayer and multilayer graphene on the surface of nickel foam using CVD method with polystyrene?PS?as carbon precursor.?2?Electrochemical properties of MnO₂/graphene composites.We synthesized MnO₂/graphene composite by hydrothermal method using GO,MnSO₄,KMnO₄.A graphene-covered nickel foam was used as a current collector for the assembly of the electrode sample prior to electrochemical testing.The electrode showed good electrochemical performance.Among them,the specific capacitance of the composite material prepared with GO 1.36g,MnSO₄·H₂O 1g and KMnO₄ 1g the properties of the material are at their best...