Study On Preparation And Eletrochemical Perfomance Of Sn Doped RGo/MnO₂ Composite

With the advent of the new century,fossil fuel consumption has led to energy crisis and environmental pollution.Experts and scholars pay close attention to and research new energy sources such as water,wind,solar and tidal energy.They are committed to replacing fossil fuels with new energy sources.The output form of new energy is not stable and how to store energy is the most important thing.As a kind of energy storage device,supercapacitor has the advantages of small volume,charging and discharging time period and high power density.It stores energy as electric energy and is environmentally friendly.It is a widely used energy storage device.At present,electrode materials directly affect the electrochemical performance of supercapacitors.Carbon-based materials,metal oxide materials,and conductive polymer materials are the main materials of electrode materials for supercapacitors.After repeated research by experts and scholars,a single material cannot produce supercapacitors with excellent performance,and excellent electrode materials can be prepared by mutual synthesis between materials.Based on this,graphene in carbon-based materials is selected as the base material,and manganese dioxide is attached to the graphene to improve the properties of the material.Then the composite material is doped with Sn to greatly increase the specific capacitance of the material.Graphene oxide is prepared by the modified Hummers method,and urea is used as a reducing agent to prepare graphene.The effect of the preparation process on the microstructure and properties of graphene was investigated by changing the ratio of reactants,reaction temperature and reaction time.Through the structural characterization and electrochemical analysis of the material,it was found that the prepared graphene was a wrinkle-like structure of the tulle sheet.When the mass ratio of graphene oxide to urea was 1:30,the reaction temperature was 160°C,and the reaction time was 3 hours,the best performance of graphene is prepared.The best performance graphene has a specific capacitance of 65.24 F/g.The hydrothermal method was used to combine graphene with manganese dioxide.The ratio of reactants,reaction temperature and reaction time were changed to explore the experimental process.The material characterization and electrochemical analysis of the material showed that the prepared graphene/manganese dioxide composite material was nanorod-like manganese dioxide attached to the surface and gap of the layered graphene.When the amount of potassium permanganate was 2 g,the reaction temperature was160°C and the reaction time was 6 hours,the prepared composite had the highest specific capacitance and was 120 F/g.Then the composite material is doped with Sn,doped by chemical precipitation method,the reaction material ratio and reaction time are controlled,and the influence of the process on the microstructure and properties of the material is investigated.The microstructure of the prepared Sn-doped graphene/MnO₂ composite is nanorod-like manganese dioxide attached to the surface and gap of the layered graphene,and Sn is distributed on the surface of the composite with tin oxide particles,and its electrochemical performance is significantly improved.When the amount ratio of Mn/Sn substance in the reactant is 10:1 and the reaction time is 60min,the prepared Sn-doped rGO/MnO₂ material has the highest specific capacitance of 180 F/g.In the cycle stability test,the material specific capacitance retention rate was 78.8%after 1000 cycles.