The Electrochemical Performance And Preparation Of Composite Electrode Based On PEDOT

Supercapacitors are a new type of energy storage device that between batteries and traditional flat capacitors.They have the advantages of high power density,fast charging and discharging,and high safety,making them a research hotspot in the field of energy storage devices.The electrode material plays a decisive role in the performance of supercapacitors,among which PEDOT is a common conductive polymer with excellent conductivity,cycling stability,and environmental compatibility.However,it also has the disadvantage of low capacitance performance,which cannot meet the requirements of practical energy storage device applications.While conducting polymers such as PPy and PANI have extremely high pseudo capacitance,they also have the disadvantage of poor cycle stability.Therefore,how to learn from its strengths and make up for its weaknesses has become the key to preparing high-performance electrodes.Based on this,this paper first prepared PEDOT:OTF electrode material with excellent electrochemical performance through oxidative polymerization.Then,PEDOT/PPy and PEDOT/PANI composite electrodes were synthesized through oxidative polymerization and electrochemical polymerization,providing ideas for the development of high-performance supercapacitors.The main research content is as follows:（1）PEDOT:OTF electrode was successfully prepared by oxidative polymerization.The microstructure of PEDOT:OTF was characterized by SEM and AFM.The conductivity was measured in a four probe system.The electrochemical performance of the electrode in different collectors was tested by CV,GCD and EIS.The results indicate that compared with the commercialized PEDOT:polystyrene sulfonic acid（PSS）,PEDOT:OTF has better electrochemical performance under the same conditions.Chemical oxidation polymerization of PEDOT:OTF has a conductivity of up to 743S/cm,and the PEDOT:OTF film formed on ITO has the best specific capacitance and cyclic stability among three types of collector fluids:glass,conductive indium tin oxide（ITO）,and polyethylene terephthalate（PET）/ITO.It can achieve a mass specific capacitance of 284.4 F/g in 1 M H₂SO₄ electrolyte at a current density of 2 A/g.When the current density increases from 2 A/g to 8 A/g,its rate performance approaches 100%.After 10000 cycles at a current density of 2 A/g,there is still 98.1%capacitance retention.（2）The PEDOT/PPy composite electrode was prepared by a two-step method of chemical oxidation polymerization and electrochemical polymerization.The electrode composition and morphology were characterized by SEM,Fourier transform infrared spectroscopy（FTIR）,XRD,and AFM.In addition,the electrochemical properties of the electrode were studied using CV,GCD,and EIS.The results indicate that due to the presence of highly conductive active material PEDOT,PPy polymerization is more dense and regular,resulting in higher crystallinity and specific surface area of PEDOT/PPy composite electrodes,greatly improving specific capacitance and cycling stability.It achieved the highest capacitance value（551 F/g）at a current density of 2A/g,and maintained a capacitance of 74.6%after 10000 cycles at this current density.（3）The PEDOT/PANI flexible composite electrode was prepared by a two-step method of chemical oxidation polymerization and electrochemical polymerization.The fractal morphology of the PEDOT/PANI composite electrode was studied using SEM,FTIR,XRD,and XPS.The electrochemical properties of the electrode were tested using electrochemical methods such as CV,GCD,and EIS.The results indicate that PANI grown on PEDOT has a coral like network interpenetrating structure,resulting in a high specific surface area and increased electron transport channels.In addition,due to the mutual diffusion and permeation of the two active materials,the conductivity of the electrode is greatly improved.Thus,the PEDOT/PANI composite electrode has higher capacitance and electrochemical stability.Its specific capacitance can reach 647.8 F/g in an electrolyte of 1 M H₂SO₄ at 2 A/g.The specific capacitance of the assembled supercapacitor can reach 154.9 F/g.At a power density of 796 W/Kg,the energy density reaches 27.1 Wh/Kg,and the stability of the device can reach 75.8%under 10000 cycles.This paper prepared PEDOT/PPy and PEDOT/PANI composite electrodes through in-situ oxidation polymerization and electrochemical polymerization methods,respectively,and used them for supercapacitors.Research has found that this electrode has good supercapacitor performance and shows good application prospects in the field of flexible supercapacitors.