Preparation And Study Of Functionalized Graphene Composite And Its Electrochemical Properties

The single two-dimensional plane and the complete sp~2 structure endow graphene with many excellent properties,which can be used in many new energy fields such as photovoltaic devices,smart sensors,supercapacitors,and hydrogen storage materials.However,because of the Van Der Waals effect between the inherent sp~2 network structures,the graphene sheets are stacked,which is equivalent to the stacking of four graphene planes into two effective specific surface areas,resulting in a decrease in the specific surface area.Thereby affecting the composite and conductive properties of other materials.Doped polyaniline exhibits excellent electrical conductivity,electrochemical characteristics,and optical properties due to oxidation-reduction reactions,and has also been widely used.However,volume collapse occurs during charging and discharging,which affects its cycle stability,limiting its application.To comprehensively solve the above problems,in this work,a variety of reducing agents were used to reduce and functionalize graphene;then the graphene/polyaniline composite is prepared by covalent grafting or blending;in addition,p-phenylenediamine was used to adjust the aspect ratio of polyaniline to explore the changes in the electrochemical performance of composites under different forms of polyaniline.X-ray diffraction,FT-IR,Raman spectroscopy,UV-Vis spectrophotometer,SEM,TEM,etc.were performed to explore the structure and morphology of composites,and the electrochemical workstation was used to study the electrochemical performance of composites.Graphene oxide was reduced and functionalized by resveratrol,a natural extract,and blended with aniline monomer,using ammonium persulfate as the initiator to prepare graphene/resveratrol/polyaniline composites.The results show that the prepared graphene has the highest degree of reduction under the reaction time of 24h,and the composite prepared on this basis exhibits more excellent electrochemical performance.Using tea polyphenols to prepare functionalized reduced graphene oxide,and through Mannich reaction to provide reactive sites for the in-situ graft polymerization of aniline monomers,a sandwich graphene/polyaniline composite material was prepared.Through analysis,it is proved that the above method could expand the graphene layer spacing and provide advantages for the intercalation polymerization of aniline monomer;the graphene sheet layer can retard the structural collapse of polyaniline;the covalent grafting greatly reduces the graphene and Interface contact resistance between polyaniline.On the basis of the above,the morphology of polyaniline was controlled by p-phenylenediamine,and graphene/polyaniline fiber composites were prepared.The results show that as the amount of p-phenylenediamine increases,the aspect ratio of polyaniline will decrease;with the higher amount,it will have an inhibitory effect on the polymerization of polyaniline.Through electrochemical tests,it is found that when the ratio of p-phenylenediamine to aniline monomer is 1:2,the prepared electrode material has the most excellent electrochemical performance.When the current density is 0.5A/g,its mass specific capacitance can reach 538.1F/g.The graphene/polyaniline composite prepared by the above research results not only solves the problem of re-stacking graphene sheets,but also solves the volume change of polyaniline during charging and discharging,which greatly improves the graphene/polyaniline composite The specific capacitance and cycle stability of the material provide an effective idea for the preparation of graphene/polyaniline composites with more efficient and higher specific capacitance.