Preparation Of Graphene-based Gels And Its Application In Supercapacitors

As a new type of energy storage device,supercapacitors are widely used in the fields of electric vehicles,rail transit,and power grid energy storage because of their extremely high power density,good cycle life,and extremely fast charge and discharge efficiency,but its low energy density is also severely limits its application prospects.The electrical conductivity and specific surface area of electrode materials are the key to determine the energy density of supercapacitors.The graphene-based gel materials has the advantages of penetrating network skeleton,oversize specific surface area,excellent conduction and thermal conductivity.Therefore,graphene-based gel materials are expected to replace traditional porous carbon electrode materials for high energy density and flexible supercapacitors.In this paper,graphene-based 3D gel materials were assembled using unchemically modified graphene and carbon nanotubes,and used as electrode materials in the field of supercapacitors.In the specific implementation process,first of al,we use liquid phase exfoliation to prepare graphene that has not been chemically modified,and hydrophilically modify the carbon nanotubes,and use the synergistic assembly of the two,under ultrasonic,grinding and other external forces.Subsequently,in order to further explore the mechanism of gel assembly,a graphene-based aerogel material with more uniform network structure and better performance was expected.In this study,hydrazine formic acid was introduced on the basis of the above system,and the graphene-based 3D network was assembled using the p H-responsivity of the solubility of hydrazine formate as a driving force for gel assembly.This assembly method was used to prepare the supercapacitor electrode in situ in the nickel foam.The results showed that: 1)The gel network structure assembled by ultrasonic force and other external forces has more agglomeration;the third component of hydrazine formate is added to the system,and the resulting gel network has a uniform structure and excellent electrical conductivity.2)The electrode materials are assembled.The electrochemical performance of the double layer capacitor was tested in 6 M KOH electrolyte.The results show that the cyclic voltammogram can still maintain a good rectangular shape at a scanning speed of 800 m V/s.Layer capacitance characteristics;using galvanostatic charge and discharge tests,the specific capacitance can reach 150 F/g and 142 F/g,respectively,at 0.5 A/g and 1 A/g;after 3000 cycles,initial specific capacitance can still be maintained 95%,indicating that it has good cycle characteristics.In conclusion,this paper proposes a new idea of assembling graphene-based 3D gels,and realizes the three-dimensional assembly of unmodified graphene using a simple and quick assembly method,and applies it as a supercapacitor electrode materials applied in the field,and demonstrate the excellent characteristics of electric double layer capacitance.