Study On Preparation And Capacitance Performance Of Graphene-Based Composite Supercapacitor Electrode Materials

With the rapid development of human society since the 21st century,energy shortage and environmental pollution have become major problems that have troubled social progress.The study of new energy storage devices is imminent,and super capacitors have the advantages of high power density,rapid charge and discharge,and no need for maintenance.The key factor affecting the performance of supercapacitors is the selection of electrode materials.Generally,super capacitor electrode materials are divided into four categories,namely carbon materials,conductive polymers,metal oxides and composite electrode materials.In order to better to improve the performance of electrode materials,researchers use different types of materials for compounding.This method can not only take advantage of the two electrode materials,but also make up for the defects of its own materials.In this paper,a new method is designed to prepare graphene aerogel(GH)with controlled pore structure,so as to make better use for flexible devices and other fields.The electrochemical performance was characterized.Because GH has an excellent pore structure,the specific capacitance value can reach 229 F/g at an electrolyte pH=5 and a current density of 1 A/g.Electrochemical deposition method was used to prepare MnO2/GH-2 composite materials,and the effects of different deposition and test conditions on the properties of composite materials were explored and analyzed.The results show that when the electrochemical deposition time is 30 s,the test voltage is 1.0 V,and the electrolyte is 1 M H2SO4 solution,the composite material exhibits more excellent electrochemical performance.The specific capacitance value of the GH-2 material tested for a current density of 1 A/g is 229 F/g,while the specific capacitance value of the material after compounding can reach 530 F/g,and the capacitance value is increased by 301 F/g.The composite material have excellent stability,and the capacitance retention rate can reach 68%.The excellent pore structure of GH will effectively shorten the ion diffusion path and significantly improve the electrochemical utilization rate of the active material.Because its unique three-dimensional structure can prevent sheet stacking,the addition of GH has greatly improved the performance of the composite material.In this paper,a new preparation method of flexible graphene paper(GP)is designed.Carry out electrochemical performance characterization,because GP does not add a binder and thus further enhances the efficiency of charge transfer and ion transport.At a current density of 1 A/g,the specific capacitance of graphene paper with a GO content of 3 mg/mL can reach 184 F/g.We prepared the MnO2/GP composite material by electrochemical deposition method,and explored the effects of different deposition and test conditions on the performance of the composite material.The results show that when the electrochemical deposition time is 30 s,the test voltage is 1.0 V,and the electrolyte is 1 M H2SO4 solution,the performance of the composite is optimal.The combined capacitance can reach 410 F/g at a current density of 1 A/g,and the capacitance increases by 226 F/g.In this paper,a one-step method was used to prepare a large amount of flaky graphene paper(GP)with black metallic luster,and PANI/GP composite materials were prepared by electrochemical deposition.The effects of different deposition and test conditions on the properties of composite materials were explored.The results show that when the electrochemical deposition time is 30 s,the test voltage is 0.8 V,and the electrolyte is a 1 M H2SO4 solution,the composite material has excellent electrochemical performance.The specific capacitance value of the composite material can reach 605 F/g,while the specific capacitance of graphene paper alone is only 184 F/g,and the composite value increases the capacitance value by 421 F/g.The preparation of graphene paper does not use binders and conductive agents,which enhances the efficiency of charge transfer and ion transmission,and greatly improves the electrochemical performance of the composite material.