Research Of Polymer-based Flexible Fibrous Electrode Materials And Their Electrochemical Properties

With the shortage of energy and the goal of carbon peak and carbon neutral strategies,there is an urgent need to develop renewable energy sources to replace traditional fuels.However,renewable energy sources have disadvantages such as unstable output and timeliness,so energy storage devices are needed to convert renewable energy sources into electrical energy and at the same time make the electrical energy achieve a stable output.Scientists have made a lot of research in the fields of lithium-ion batteries and supercapacitors,and these devices have been used in various electronic products as well as new energy vehicles and other fields.In recent years,in the development of society,people’s demand for quality of life has become higher and higher,and flexible wearable electronic products have gradually entered people’s lives.Among many super supercapacitor devices,fibrous supercapacitors have the advantages of lightweight,small size and wearability in addition to all the advantages of supercapacitors.The selection of a suitable method to prepare high-performance flexible fibrous supercapacitors is very important for the performance of electrochemical energy storage devices.In this paper,the selection of fiber flexible carriers,the growth method of the conducting polymer polyaniline and the influence of the structure of the fibers on the performance of flexible electrode materials are investigated in three aspects as follows:（1）Preparation of polyaniline-poly（ether）sulfone flexible fiber electrode by wet spinning technique.Porous flexible fiber electrode materials were prepared by direct wet spinning of a spinning solution containing acetylene black,poly（ether）sulfone,and aniline monomer,and the solidification bath was an aqueous 1.0 M H₂SO₄solution containing ammonium persulfate.The effect of poly（ether）sulfone concentration on the electrochemical properties of the fibrous electrode materials was investigated.The results showed that when the concentration of poly（ether）sulfone was 15wt%,the area specific capacitance of polyaniline-poly（ether）sulfone fiber could reach 887.5 m F cm^-2and the volume specific capacitance was 35.6 F cm^-3when the current densities were 2 m A cm^-2and 25 m A cm^-3,respectively.（2）In order to increase the capacitive performance of the fiber electrode,this chapter prepares polyaniline-sulfonated poly（ether）sulfone fiber electrode materials by wet spinning.The effects of different sulfonation degrees of poly（ether）sulfone on the electrochemical properties of the fiber electrode materials were investigated.The experimental results show that when the sulfonation degree of poly（ether）sulfone is 14%,the electrochemical performance of the sulfonated poly（ether）sulfone-polyaniline fiber electrode material obtained is the best.The area specific capacitance of sulfonated poly（ether）sulfone-polyaniline was1390 m F cm^-2at a current density of 2 m A cm^-2and its volume specific capacitance was 69.5F cm^-3at a current density of 25 m A cm^-3.（3）To further increase the electrochemical performance and cycling stability of the fiber electrode.In this chapter,the SSF-MWCNT fiber electrode was firstly prepared by adding MWCNT-COOH to the spinning solution.The effect of MWCNT-COOH on the electrochemical performance of the electrode materials was investigated by comparing the electrochemical performance of PANI-SPES and SSF-MWCNT electrode materials.To investigate the effect of fiber structure on the electrochemical performance of the fiber electrode,HSF-MWCNT hollow fibers were prepared by coaxial wet spinning.The experimental results revealed that the flexibility and electrochemical performance of the sulfonated poly（ether）sulfone-polyaniline hollow fiber electrode material were better than those of the solid fiber electrode.The specific capacitance of the hollow fiber electrode material could reach 1737.5 m F cm^-2at 2 m A cm^-2under a three-electrode test system.The all-solid-state supercapacitor device assembled with two HSF-MWCNT fiber electrodes still had an energy density of 1.65 Wh cm^-3at a power density of 159.9 W cm^-3.