Research On Regulation Of Conductive Polymers Functionalized Multidimensional Carbon Structure And Supercapacitor Performance

Flexible supercapacitors（SCs）have attracted much attention because of their flexibility,high power density and long cycle life.However,its inherent low energy density and unsatisfactory cycle stability at large rates severely limit the practical application of flexible SCs in life.Therefore,the development of SCs that integrate high performance and flexibility is an urgent problem to be solved.This thesis aims at the problems of few connection positions,weak force,high interface resistance and unstable structure in the composite of conductive polymer and carbon material.Through interface control and structural design,fully utilizing the high theoretical pseudo-capacity of conductive polymer and high conductivity of carbon skeleton,the three-dimensional（3D）conductive frame formed by cross-linking graphene oxide is used as carrier,in-situ growth/crosslinking/anchoring of conductive polymer on/in its surface/pores,synthesized a flexible 3D porous carbon-loaded conductive polymer system that can provide a fast electric/ion transmission channel,and realize the dual energy storage mechanism of electric double layer and pseudocapacitance at the same time,so as to meet the requirements of flexible SCs with high energy density and high power density.The specific research content is as follows:（1）The flexible composite electrode material with polyaniline（PANI）modified reduced graphene oxide（RGO）surface was synthesized by in-situ polymerization and self-assembly in water bath.Compared with traditional physical mixing,PANI grown in situ can establish rapid electron transport between RGO and improve the efficiency of PANI’s redox reaction.At the same time,PANI is used as a spacer,which can effectively alleviate the high-density stacking of RGO and increase the specific surface area.The results show that the electrode exhibits a specific capacity of 592 F g^–1,and the symmetrical SC has an energy density of 19 Wh kg^–1 with a cycle life of 81.3%after 5000 cycles of charging and discharging.（2）In order to solve the problems of insufficient flexibility of the composite electrode and the decrease of specific capacitance caused by the blockage of ion channels by in-situ polymerized PANI,spring-like spiral carbon nanotubes（HCNT）were introduced as flexible support,and a flexible composite electrode with PANI embedded in a 3D porous network was prepared by hydrothermal self-assembly combined with carbonization cross-linking reaction.The mechanical interlocking effect of HCNT cooperates with GO to build a stable and flexible conductive network,and then through high temperature cross-linking pre-embedded PANI to control and shape the micro/mesoporous structure and increase the ion transmission rate.The results show that the electrode has a high specific capacity of 696.75 F g^–1,and the cycle life of SC has also been improved,5000 cycles maintain 85.3%of the initial capacitance.（3）Polythiophene（PEDOT）with a wider reaction potential can meet the needs of high voltage and energy density in specific fields.Using photochemical reduction combined with H₂O₂ etching pore-making strategy,PEDOT was anchored on the surface/interlayer of porous RGO,and a flexible composite electrode with a 3D layered porous configuration was synthesized.The controllable etching RGO scheme can shape a regular ion transmission channel,and at the same time,PEDOT anchors the stable interface contact of RGO,which can effectively exert the pseudocapacitance characteristics of PEDOT.Electrochemical tests show that the electrode has a specific capacity of 535.5 F g^–1 under a voltage window of 1.2 V,while the energy density of the symmetric SC is significantly increased to 44.66 Wh kg^–1,and it has good performance retention under large-angle bending.