Preparation And Electrochemical Properties Of Carbon Fiber/polypyrrole Composite Electrode

Due to the non-polar and non-activated surfaces of carbon fibers,the lack of chemical bonds and effective physical interactions between the carbon fibers and the polypyrrole functional layer results in relatively poor electrochemical performance of the carbon fiber/polypyrrole composite electrode.Therefore,in order to improve the problem of low bonding between the carbon fiber and the polypyrrole,it is necessary to modify the surface of the carbon fiber.Plasma technology is used to pretreat the surface of carbon fiber,followed by liquid deposition of polypyrrole.The interfacial properties of carbon fiber/epoxy composites by plasma pretreatment were studied.The results show that the interfacial shear strength increases 260%after plasma pretreatment of polypyrrole on carbon fiber.The analysis results show that the reason for the increase of the interfacial shear strength is not only related to the mechanical riveting between the fiber/resin but also to the force of the interface.Plasma pretreatment can increase the number of carboxyl groups on the surface of carbon fiber and form hydrogen bonds between carboxyl groups and PPy to enhance the interfacial properties of carbon fiber composites.Polypyrrole/carbon fiber composite electrode was prepared by polymerizing polypyrrole on the surface of carbon fiber by gas-phase polymerization.The results show that after pretreated with pyrolytic carbon,the content of oxygen-containing groups on the surface of carbon fiber increases and the protonation degree of the composite electrode increases.When the current density is 0.250A/g,the specific capacitance increases by 28.6%.Because carbon fiber and polypyrrole The interfacial interaction between them is hydrogen bond,which also shows excellent cycling stability with an initial capacitance of 85.4%after 4000 charge/discharge cycles.The effects of plasma pretreatment and grafted acrylic acid pretreatment on the electrochemical performance of carbon fiber/polypyrrole composite electrode were compared.The results showed that the graft acrylic acid treatment could produce more oxygen-containing functional groups on the surface of carbon fibers than the plasma treatment,resulting in a higher protonation level of polypyrrole.The specific capacitance increased by 72.7%when the current density was 0.250 A/g.The hydrogen bonding force between carbon fiber and polypyrrole is enhanced,showing better cycling stability,and the initial capacitance can maintain 93.3%after 4000 charge/discharge cycles.