Preparation And Capacitance Performance Of Composite Electrode Materials Based On Polypyrrole/polyimide

With the rapid development of new energy technologies,it is urgent to develop new energy storage devices,among which supercapacitors have become a research trend because of their environment-friendly,flexible and portable.As a core component,the structure and properties of electrode affect the charge storage capacity and mechanical properties of capacitors,it is of great significance to develop a flexible electrode material with excellent capacitance performance.Polyimide（PI）fiber has the advantages of excellent mechanical stability and flexibility to meet the requirements of flexible electrode materials.Polypyrrole（PPy）is well known in the field of conductive materials because of its low cost,excellent electrical conductivity and simple synthesis.In this paper,PI fiber membranes as the electrode substrate to prepare the polypyrrole/polyimide（PPy/PI）and polypyrrole/Reduced graphene oxide/polyimide（PPy/RGO/M-PI）composite electrode materials,analysis and study the structure and capacitance of electrode materials.Flexible porous PI fiber membranes were prepared by electrospinning technology,and PPy was deposited on the PI fiber membranes to prepare the PPy/PI composite electrode materials by in-situ polymerization.M-PI membrane was prepared by sensitizing the PI membrane to stannous dichloride（Sn Cl₂）.Reduced graphene oxide（RGO）was prepared by microwave assisted method,and PPy/RGO/M-PI composite electrode materials were prepared by electrostatic self-assembly and in-situ polymerization.The composition,morphology,conductivity and electrochemical properties of the composite electrode materials were analyze through FT-IR,XRD,XPS,Raman,SEM,porosity,conductivity,CV,GCD and EIS tests.The capacitive behavior of PPy/PI electrode and PPy/RGO/M-PI electrode was investigated.PPy/PI composite electrode materials have the most uniform morphology when the concentration of pyrrole monomer is 0.35 mol/L and the polymerization time is 5 h,the conductivity is 1.12 S/cm.The porous structure of PI fiber membranes provides abundant electrochemical active sites for PPy,which makes PPy/PI composite electrode materials has excellent electrochemical performance The areal capacitance is 791.67 m F/cm² at 0.5 m A/cm²,the capacitance retention rate is 80.85%after 3000 cycles,and the contribution rate of surface control capacitance is 92.74%at 50 m V/s.After the introduction of RGO,the conductivity of PPy/RGO/M-PI composite electrode materials can reach 1.70 S/cm,the areal capacitance is 1437.12 m F/cm² at 0.5 m A/cm².Moreover,the cyclic stability of PPy clectrode was improved.After 3000 cycles,the capacitance retention rate was 89.33%.After 500 bends,the capacitance is maintained at99.80%of the initial capacity.What’s more,PPy/RGO/M-PI liquid symmetric supercapacitors exhibit capacitive capabilities.The areal capacitance is 363.09 m F/cm² at 0.5 m A/cm².The maximum energy density and power density are 32.28μWh/cm² and 8.1 m W/cm²,and the capacitance retention rate is 82.92%after 3000 cycles of testing.