Controlling The Aggregation Structure Of PEDOT:PSS Films And Research On Their Supercapacitive Properties

With the increasingly prominent energy problem and the progress of science and technology,new energy storage technology is becoming more and more important.The supercapacitor is one of the most widely studied energy storage devices.As a critical factor in measuring supercapacitors’performance,electrode materials have been extensively studied to improve their charge storage capacity.Conductive polymers（CPs）with excellent conductivity are considered to be one supercapacitor electrode material with high application potential.Therefore,preparation methods and performance control have attracted much attention in recent years.However,the properties of CPs are closely related to their structures,especially the aggregation structure,which can greatly affect ion/electron transport.Exploring the internal relationship between the arrangement and accumulation of molecular chains and charge storage can provide more consideration for the further design and performance improvement of CP-based electrodes.In this work,the aggregation structure of poly（3,4-ethylenedioxythiophene）:polystyrenesulfonate（PEDOT:PSS）was regulated based on the induction of solvent and the space size effect of multidimensional composites.Combined with characterization analysis and performance tests,the influence of PEDOT:PSS molecular chains on the charge transfer and storage process were systematically studied:1.Multiple PEDOT:PSS films with different aggregated structures were prepared by solvent treatment.Among them,the PEDOT:PSS film doped with deionized water（DI）（PEDOT:PSS/DI）has the highest capacitance value(248.4 F g^-1),which is mainly due to its good aggregation structure providing good coupling of ions/electrons transmission.Decreasing theπ-πstacking distance is helpful for the transmission of electrons,and increasing the interlayer spacing is more conducive to the diffusion of ions.Therefore,the optimization of the energy storage process of PEDOT:PSS films is closely related to the regulation of the aggregation structure.However,when the change of the aggregated structure only has a single effect on the transmission of ions or electrons,it will limit the optimization of the capacitance performance of the electrode material.Therefore,the adjustment of the aggregate structure of the PEDOT:PSS film through solvent treatment can provide a meaningful reference for optimizing CP-based electrode materials.2.PEDOT:PSS was composited with multidimensional carbon materials to explore the influence of spatial size effect on the aggregation structure of PEDOT:PSS-based films.Among them,zero-dimensional fullerene(C₆₀)mainly affects the arrangement of PEDOT:PSS molecular chain through volume steric effect.The severe agglomeration of one-dimensional single-walled carbon nanotubes（SWCNT）and the weak interaction with PEDOT:PSS makes the PEDOT:PSS/SWCNT capacitance poor.The goodπ-πinteraction between reduced graphene oxide（rGO）with two-dimensional layered structure and PEDOT:PSS is conducive to transforming the PEDOT:PSS molecular chain to the linear structure.The synergistic effect between the two promotes the contact between the electrolyte ions and activity materials makes the PEDOT:PSS/rGO film obtain a high capacitance value of 215.6 F g^-1(1 A g^-1)and a good rate performance（97.8%）.Therefore,the addition of composite materials with different dimensions is also an effective way to control the aggregation structure of PEDOT:PSS thin films,which helps to further improve the capacitance performance of PEDOT:PSS-based electrode materials.