Study On Preparation And Performance Of Polyaniline/Carbon Series Electrode Materials

Polyaniline is one of the most promising electrode materials because of its high capacitance,low cost,easy synthesis and environmental friendliness.However,during the charge and discharge process of polyaniline,the molecular chain shrinks and expands,resulting in polyaniline having relatively poor cycle stability.In order to maintain high capacitance during long-term cycles,it needs to be compounded with carbon materials to improve its stability.In this paper,supercritical CO₂ was used as a technical means to use the characteristics of supercritical CO₂,such as low viscosity,high diffusion coefficient,small molecular size and low interfacial tension,to assist the intercalation of aniline cationic monomer with graphite,and then performed in-situ chemical oxidation polymerization to synthesize polyaniline/graphite and graphite-polyaniline composite materials,and their morphology and electrochemical properties were studied.The pretreatment of supercritical CO₂ could assist the aniline cationic monomer to enter between the graphite layers,and then chemically oxidize and polymerize to form a polyaniline/graphite layer by layer composite structure.When the supercritical pretreatment condition was 120? and 16 MPa,the specific capacitance of the obtained composite material was the highest,and the specific capacitance was 406.1 F/g at a current density of 5 A/g.When the current density was 20 A/g,its capacitance retention rate was 95%,its excellent rate performance was derived from structural advantages.Polyaniline pellets were used as interlayer materials to provide high specific capacitance.Graphite was a stable and conductive network to ease the volume change of polyaniline,so that the resulting composite material had high specific capacitance and excellent rate performance.In situ chemical oxidative polymerization of aniline was carried out at-30?,which made polyaniline exist on graphite surface in needle form.As the polymerization time increased,the length of the needle-like structure increased.When the polymerization time was 24 h,the specific capacitance of the composite material at a current density of 5 A/g was 222.1 F/g.When the current density was 20 A/g,its capacitance retention rate was 98.2%,which was mainly due to the fact that needleshaped polyaniline had a shorter ion and electron transport path and could ease the change in its volume.The polyaniline/graphite composite prepared in this article had good electrochemical properties and can be used in fields such as supercapacitors.