Preparation Of Conductive Polymer Matrix And Its Composites And Their Applications In Supercapacitors

Compared with the built-in batteries,And the supercapacitor is a potentially powerful maintaining power device which has its own advantages,such as high power density,fast charge and discharge rate and long service life.And what determines the main performance of the supercapacitor is the electrode material.Conductive polymers is a promising material for supercapacitor electrode because of its high conductivity and low toxicity.However,the poor cycle stability of conductive polymers limits its application.Generally,controlling the morphology and structure and compounding with transition metal oxides and carbon materials can be used to boosting the defect mentioned above of the conductive polymers.A typical conductive polymer polypyrrole,was used as the precursor,the polymerization process of polypyrrole was controlled by template method,and the innovative hollow four-prism structure was obtained.The application of polypyrrole-based carbon materials in energy field was expanded by introducing MoO₃and glucose to prepare composites with good properties.The main work of this paper as follows:1.Using methyl orange(MO)and polyvinylpyrrolidone(PVP)as double template and Fe Cl₃ as initiator,hollow four-prism conductive polypyrrole was prepared by chemical oxidation method at low temperature.The effects of PVP dosage on the morphology,structure and electrochemical properties of polypyrrole were characterized by SEM,XRD and XPS.It was found that hollow four-prism polypyrrole was prepared by PVP and Mo double template method.When the addition amount of PVP is 0.2 g(NQMP-0.2),the hollow four-prism morphology of polypyrrole is the most regular,nevertheless,this hollow structure provides convenient channels for ion transport.The results of XPS showed that MO not only induced the synthesis of polypyrrole hollow morphology as a soft template,but also but also successfully doped polypyrrole with S atom,which provides a considerable pseudocapacity.The electrochemical performance of NQMP-0.2 was tested in 1 mol L^-1 KCl electrolyte.When the current density is 0.5 A g^-1,the specific capacity of NQMP-0.2 can reach 179 F g^-1,and when the current density is 10 A g^-1,the specific capacity can maintain 61%when the current density is 1 A g^-1.This result showed that compared with compared with the tubular and granular polypyrrole,NQMP-0.2 not only has a unique hollow four-prism morphology,but also has a great improvement in electrochemical performance,which enhances the development potential of polypyrrole in supercapacitors.2.MoO₃@PPy composite was prepared by chemical oxidation method using MoO₃as hard template and Fe Cl₃ as initiator.The SEM,XRD and other characterization methods were used to investigated the effects of MoO₃ as hard template on the morphology,structure and electrochemical properties of polypyrrole.SEM shows that the MoO₃@PPy composite has a thorn-like morphology,after high temperature treatment,MoO₃ decomposes and collapses slightly,and the semi-hollow thornlike polypyrrole based carbon composite material was obtained.EDS images show that the surface of MoO₃@PPy composite material is rich in heteroatoms,which increases the wettability of the material and gives it excellent capacitance performance.When the current density is1 A g^-1,the specific capacitance of MoO₃@PPy-700 can reach 300 F g^-1 and 221 F g^-1under the current density of 10 A g^-1,and the ratio performance of MoO₃@PPy-700 can reach 74%.The morphology of half-hollow thorns was obtained,and abundant pseudocapacitance was provided as Mo source by leading in MoO₃ as a hard template.This work provides an economical and feasible strategy for the preparation of conductive polymer matrix composites.3.Using glucose and polypyrrole as raw materials and melamine as nitrogen dopant,the nitrogen-doped glucose@PPy composite carbon material was prepared by hydrothermal and activated carbonization with the assistance of sodium dodecyl sulfate.The effects of glucose on the morphology,structure and properties of polypyrrole were studied by SEM,Raman and N₂ adsorption and desorption methods.The SEM showed that the glucose@PPy composite carbon material was solid microsphere,and Raman showed that the composite carbon material had appropriate graphitization degree(I_G/I_D=1.01).The results of N₂adsorption and desorption showed that the carbon composite had a higher specific surface area(1545.8 m² g^-1),which exposed more active sites,and more mesopores provided sufficient ion storage,which improved the transport rate of electrolyte ions.In 2 mol L^-1 H₂SO₄ aqueous solution,the specific capacitance of the composites is 387 F g^-1 at the current density of 1 A g^-1,and 323 F g^-1 at the current density of 10 A g^-1,indicating that the material has good rate performance.Moreover,after 10000 cycles at the current density of 10 A g^-1,the capacitance retention rate of the material is 92%.This work provides an effective strategy for the preparation of high performance polypyrrole based carbon composites and expands the application of polypyrrole in the energy field.