Preparation And Electrochemical Energy Storage Performance Of PVA-Based Flexible Composite Electrode Material

In recent years,with the rapid development of artificial intelligence（AI）technology,the market of wearable electronic devices has also promoted booming.In order to meet the demand for more comfortable wearable electronic devices,flexible wearable electronic devices have attracted much attention.The difficulty of flexible devices lies in the flexibility of their energy storage devices.Many researches are devoted to making their energy storage devices compact,flexible and lightweight to make the whole device flexible.Be stretchability of flexible supercapacitor is an effective way to solve equipment flexibility,but under various strain conditions,maintain its superior electrochemical performance is still a difficult task.Based on this,the main research content of this paper is to prepare flexible electrode and assemble into flexible supercapacitor,then,study its electrochemical performance and mechanical properties.The main results are as follows:（1）PVA activated carbon composite electrode material is prepared by chemically cross-linking the rapidly-formed PVA hydrogel solution and the activated carbon powder.By adjusting the content of activated carbon,the composite electrode with 60%carbon content was determined to have the best performance,with a tensile strength of4.46 MPa and an elongation at break of 78%.The area specific capacitance was 417.13mF/cm² at a current density of 0.25 mA/cm²,and the specific capacitance retention rate was 98.5%and 94.85%,respectively,after 2000 bending folding cycles and 10000charging and discharging cycles.（2）By means of chemical polymerization,a layer of p-pyrrole doped polypyrrole was coated on the surface of activated carbon and then compounded with PVA hydrogel to obtain a flexible PVA/PPy/AC three-component composite electrode.The mass ratio of pyrrole monomer to activated carbon was adjusted to determine the best performance of the composite electrode when the mass ratio of pyrrole and activated carbon was 1:2.The tensile strength was 8.07 MPa and the elongation at break was 211%.The specific capacitance at the current density of 0.25 mA/cm² is 174.7 mF/cm²,and the specific capacitance retention rate is 96.9%and 82.9%after 10000 bending folding cycles and1000 charging and discharging cycles,respectively.（3）Using a chemically-crosslinked PVA-H₂SO₄ film（CPH）as a flexible substrate,the polypyrrole is uniformly embedded in the CPH film by means of gas phase polymerization to prepare a PPy-CPH flexible electrode and assemble a symmetrical whole Solid state flexible super capacitor.The device has a tensile strength of 20.83MPa and an elongation at break of 377%.With excellent mechanical properties,it also exhibits excellent electrochemical performance.Its maximum volumetric capacitance is 13.06 F/cm³,and its energy density is 1160.9μWh/cm³.After 10000 bending folding cycles and 10000 charge and discharge cycles.Its specific capacitance retention rate was 97.9%and 86.3%,respectively.