Preparation Of Graphene-Based Composites And Their Applications In Supercapacitors

As a new energy storage device between battery and traditional capacitor,supercapacitor has the advantages of high capacity,high power density,good stability and long life,and has been widely studied by researchers.The high capacity and stability of electrode materials directly affect the performance of supercapacitors.In addition,the development of flexible wearable devices makes it important to study flexible energy storage shell with high stability and biological safety.Graphene has excellent electrical conductivity,mechanical strength and electrochemical stability due to its unique conjugate structure.It is an excellent electrode material for supercapacitors.However,the graphene prepared by chemical method has various defects and difficult stratification,resulting in its electrochemical performance far below the theoretical value.Therefore,a series of graphene-based composites were prepared by different methods through modification of graphene,compounding with conductive polymer PEDOT and nano-silver,and their structures,morphologies,electrochemical properties and biological safety were studied and characterized.?1?Based on the preparation of thiophene functionalized graphene oxide GO-TAA material,GO-TAA-PEDOT composite with regular pie-like composite morphology was prepared by copolymerization with EDOT.Compared with GO and GO/PEDOT,the composite exhibits better electrochemical properties.When the current density is 0.3 A?g^-1,the specific capacity of GO-TAA-PEDOT composites is178.34 F?g^-1.The specific capacity of GO-TAA-PEDOT composites can be maintained 93.75%after 1000 cycles of charging and discharging at high current density(4 A?g^-1).?2?Graphene self-supporting membrane electrode material is used to replace the collector in the electrode.Sandwich-structured E-PEDOT/f-rGO composite film with needle-like loose sea urchin clusters was prepared by electrochemical polymerization.When the current density was 1 A?g^-1,the specific capacity of E-PEDOT/f-rGO composite film was 89.12 F?g^-1.After 1000 cycles of charging and discharging at high current density(5 A?g^-1),the specific capacity of E-PEDOT/f-rGO composite film could be maintained at 92.47%.C-PEDOT/f-rGO composite membranes with loose three-dimensional network structure was obtained by one-step chemical method.At current density of 1 A?g^-1,the specific capacity of C-PEDOT/f-rGO composite membranes was 129.06 F?g^-1.After 1000 cycles of charging and discharging at high current density(5 A?g^-1),the specific capacity of C-PEDOT/f-rGO composite membranes could be maintained at 94.86%.?3?A nano-silver-loaded graphene oxide composite AgNPs@GO was prepared by ultrasonic-assisted liquid-phase method,which can effectively inhibit the growth of Pseudomonas aeruginosa.The composite material was compounded in a flexible matrix.The 0.48wt%-AgNPs@GO/PE flexible composite material was selected,which has better bacteriostasis,stronger water vapor barrier and better dissolution resistance.It is expected to be applied in the shell of flexible devices.