Preparation Of Graphene-based Composite Electrode Materials And Its Application In Supercapacitors

In the process of energy development and utilization,the research and development of energy storage devices is very important.As an energy storage device,supercapacitor has the advantages of high power density,long cycle life and high charge discharge rate.Graphene is an ideal electrode material for supercapacitors,but its energy storage effect is affected by agglomeration in the electrochemical process.Therefore,it is necessary to composite graphene with transition metal oxides as electrode materials to play a synergistic role.Transition metal oxides are widely used in the research of composite materials.Among them,manganese oxides and nickel oxides have the advantages of high specific capacitance,low cost and easy availability,which have excellent research significance and value.In this paper,graphene oxide(GO)and manganese dioxide(MnO₂)were used to study and optimize the preparation conditions of binary electrode materials.The binary composite electrode materials with high C_spwere prepared under the condition of hydrothermal temperature of 140?,p H value of 11 and reaction time of 24 h.The binary electrode material was characterized by SEM,TEM,XRD,EDS,XPS and its electrochemical properties were tested.The C_spis 411.37 F/g under the current density of 1 A/g.The C_spis maintained at 54.5%after2000 cycles of current charge and discharge.Based on the preparation of binary electrode materials,the preparation of ternary composite electrode materials by adding Ni Cl₂·6H₂O with different molar mass was explored.When 2.5mmol Ni Cl₂·6H₂O was added,the electrode material had higher C_sp.The electrochemical properties shows that the C_spis 553.97 F/g at 1 A/g and 75%of the C_spis retained after 2000cycles of charge discharge.The cycle performance of ternary composite electrode materials is significantly improved compared with the binary composite electrode material.In addition,a novel layered nano ternary composite electrode material was prepared by bonding polydopamine(PDA)onto graphene.After the characterizations,the nano ternary composite electrode material has the C_spof 202.44 F/g at a current density of 0.5 A/g,and the C_spof 167.95 F/g at a high current density of 10 A/g which has a retention rate of 83.00%.The C_spis57.93%after 1000 cycles of charging and discharging at 1 A/g.