Study On Fabrication And Properties Of Aniline-pyrrole Copolymer Based Electrode Material For Supercapacitor

Due to the advantages of rapid charge and discharge,high power density and excellent cycle stability,supercapacitors have attracted wide attention from researchers.Electrode material is an important factor affecting the performance of supercapacitor.Polyaniline is considered to be one of the excellent promising electrode materials due to its high theoretical specific capacitance,easy preparation,doping,and environmental friendly.However,the existing polyaniline,with poor cycle stability,is difficult to achieve its theoretical specific capacitance.In order to solve the problems of low specific capacitance and poor cycle stability of polyaniline,aniline-pyrrole copolymer and g-C₃N₄/aniline-pyrrole copolymer composites were prepared by chemical copolymerization.Finally,a self-supporting polyvinyl alcohol/aniline-pyrrole copolymer composite hydrogel electrode was prepared on the basis of polyvinyl alcohol hydrogel.The properties of the prepared materials were studied.This paper mainly includes the following aspects:?1?The conductive aniline-pyrrole copolymer is synthesized by chemical polymerization of using phytic acid as dopant acid and crosslinking agent,ammonium persulfate as oxidant.The effects of different molar ratios of aniline to pyrrole monomers on the properties of the materials were investigated.When the aniline to pyrrole monomer molar ratio is 3:1,the appearance of the durian-like morphology is obtained,which shows better electrochemical performance than polyaniline and polypyrrole.At a current density of 1 A·g^-1,its specific capacitance is 639 F·g^-1,which is much higher than polyaniline(389 F·g^-1).The specific capacitance retenton rate is 62%after 1000 cycles of galvanostatic charge/discharge at a current density of3 A·g^-1.A symmetrical supercapacitor is assembled using the copolymer as an electrode and the energy density was 12 Wh/Kg at a power density of 500 W/Kg.?2?In order to solve the problem of poor cycle stability and low energy density of copolymers,g-C₃N₄ material with high cycle stability was introduced and aniline-pyrrole copolymer is polymerized on the surface of g-C₃N₄ by in-situ oxidative polymerization for the g-C₃N₄/aniline-pyrrole copolymer composite.When the mass ratio of g-C₃N₄ to aniline and pyrrole monomer is 1:11,the performance is excellent.The specific capacitance retention rate is 88%after 1000 cycles of galvanostatic charge/discharge at a current density of 3 A·g^-1.A symmetrical supercapacitor was assembled using the composite material as an electrode.The energy density is 14 Wh/Kg at a power density of 499 W/Kg and the specific capacitance retention rate is 88%after 500 cycles of galvanostatic charge/discharge at a current density of 3 A·g^-1.?3?A PACP/PVA conductive polymer hydrogel with a three-dimensional porous network structure was prepared by a freeze-thaw method using polyvinyl alcohol as a hydrogel matrix and an aniline-pyrrole copolymer as a conductive polymer.The PACP/PVA hydrogel electrode has a strain of 100%under a tensile stress of 75 KPa.The specific capacitance of the electrode at a current density of 1A·g^-11 reaches to 441 F·g^-1.The specific capacitance retention rate is 86%after 10000cycles of galvanostatic charge/discharge at a current density of 3 A·g^-1.After 500turns of bending,the specific capacitance of the PAC/PVA hydrogel electrode at 1A·g^-11 current density is still maintained at 418 F·g^-11 and the specific capacitance retention rate is 78%after 10000 cycles of galvanostatic charge/discharge at a current density of 3 A·g^-1.An all-solid-state symmetric supercapacitor is assembled using the conductive polymer hydrogel electrode.The energy density is 52 Wh/Kg at a power density of 489 W/Kg and the specific capacitance retention rate is 74%after 1000cycles of galvanostatic charge/discharge at a current density of 3 A·g^-1.