The Preparation Of Novel PEDOT:PSS Complex And Its Application In Supercapacitors

In recent years,with the aggravation of energy crisis,sustainable renewable energy has been greatly developed,and electrochemical energy storage technology is an important technology to collect and store this kind of energy.The two most representative types of electrochemical energy storage devices are supercapacitors and lithium-ion batteries.Compared with lithium-ion batteries,supercapacitors have the advantages of higher power density,excellent charge storage capacity,high safety,longer cycle life and excellent environmental compatibility.Therefore,supercapacitors,as a new energy storage device with environmental protection and sustainability,have attracted great attention,and electrode materials are the key factors to determine the performance of supercapacitors.Conductive polymer poly（3,4-ethylenedioxythiophene）:polystyrene sulfonic acid（PEDOT:PSS）has the characteristics of high conductivity,solvability,high thermal stability,environmental friendliness and safety,and it has attracted a lot of attention as an electrode material for supercapacitors.In this paper,a novel conductive polymer composite PEDOT:CF₃SO_2（x）PSS_（1-x）was successfully prepared by introducing ionic liquid zinc di[bis（trifluoromenthylsulfonyl）imide][Zn（TFSI）₂]（CFE）into commercial PEDOT:PSS（PH1000）solution.The basic properties and electrochemical properties of the composite were studied.Based on this composite,a highly stable and high-performance solid-state symmetric supercapacitor was successfully prepared.The air stability and electrochemical stability of the supercapacitor were studied in depth,and the relationship between molecular structure and device stability was discussed in detail.In addition,a simple method for preparing PEDOT:PSS aerogel was developed by the simple process of freeze-drying technology with the help of the viscosity increase brought by CFE doping to the PEDOT:PSS solution.The relationship between the preparation conditions and the morphology of the aerogel was studied in detail.The electrochemical performance of the aerogel as an electrode was further studied,and the self-discharge performance of the electrode was further explored.The main research contents are summarized as follows:A novel conductive polymer compound PEDOT:CF₃SO_2（x）PSS_（1-x）was successfully obtained by doping ionic liquid CFE with commercial conductive polymer PEDOT:PSS（PH1000）solution.Nano-scale PEDOT:CF₃SO_2（x）PSS_（1-x）thin film was prepared by spin coating process.The film was treated with concentrated sulfuric acid,the S-PEDOT:CF₃SO_2（x）PSS_（1-x）electrode with high conductivity was obtained by further optimization.The composite exhibited a high specific capacitance of 194 F/cm³ at a current density of 0.6 A/cm³,and even at a high scanning rate of2000 m V/s,the electrode still showed excellent high rate performance.Using H₂SO₄:PVA（polyvinyl alcohol）as gel,the prepared compound S-PEDOT:CF₃SO_2（x）PSS_（1-x）was used as electrode material,and the structure of S-PEDOT:CF₃SO_2（x）PSS_（1-x）/H₂SO₄:PVA/S-PEDOT:CF₃SO_2（x）PSS_（1-x）was prepared.This device has a high specific capacitance of 70.9 F/cm³,and the optimal energy density is 6.02 m Wh/cm³ at a power density of 397 m W/cm³.After 10000 cycles,the capacitance retention rate of this supercapacitor is as high as 98%.After the device was placed in the air for 2880 hours,its capacitance retention rate was still as high as92.2%,and it was basically the same after 10000 cycles.At the same time,the mechanism of CFE optimizing PH1000 performance was analyzed,which showed that ionic liquids could be used to prepare PH1000 electrodes with excellent performance.What are the challenges in the preparation of PEDOT:PSS aerogels?The viscosity of the solution is low,and when we adjust the proportion of CFE in PEDOT:PSS（PH1000）,we find that the viscosity of the solution can be greatly improved by adjusting the proportion of CFE,which provides a way to prepare PEDOT:PSS aerogels.Excellent PH1000-CFE aerogels（Q-PH1000-CFE）were prepared by a simple freeze-drying process.SEM characterization shows that the aerogel has a large number of mesopores,and Q-PH1000-CFE has excellent strength and resilience.After simple physical compression,the aerogel can basically return to its original shape.Furthermore,the macropores in Q-PH1000-CFE were eliminated by acid treatment,and S-Q-PH1000-CFE was prepared,which was used as the electrode of supercapacitors and its electrochemical performance was measured.The specific capacitance of S-Q-PH1000-CFE electrode was 59.4 F/g at a current density of 0.6 A/cm³,and the electrode was cycled at 15000 cycles.In addition,S-Q-PH1000-CFE electrode is helpful to restrain self-discharge.The self-discharge test shows that the voltage loss of S-Q-PH1000-CFE electrode is only 14.7%after 6 h,which is better than that of thin film electrode.The prepared electrode is expected to be used in commercial supercapacitors and improve the practical application of supercapacitors.