Study On Metal Ion Doped Polythiophene And Its Nanocomposites

Supercapacitors are new-green energy storage devices,which combins the advantages of high power density of traditional capacitors and high energy density of secondary batteries.It is well know that electrode material is the key factor to influence the performance of supercapacitors.Among them,poly(3-methyl-thiophene)(PMT)is an important structural conductive polymer material,because of its high electrical conductivity,good environmental stability and easy to control the molecular chain structure and so on,it is a potentially important supercapacitor electrode material.In this paper,Mn2+,Co2+,Ni2+,Cu2+ doped PMT were prepared by chemical oxidation polymerization method.The Ni2+ doped poly(3-methyl-thiophene)(PMT,Ni)with the best electrochemical performance was selected and the synthesis process was optimized.The composite material with better electrochemical performance was obtained by optimizing the synthesis of Ni2+ doped polythiophene and graphene or carbon nanofibers.The main research contents are as follows:(1)Mn2+,Co2+,Ni2+,Cu2+ doped PMT were prepared by chemical oxidation method.Chemical structure and surface morphology were investigated by FT-IR,SEM,TGA and XRD.The electrochemical properties of materials were evaluated by cyclic voltammetry,galvanostatic charge-discharge,alternating current impedance and cycle life.Research indicated that Mn2+,Co2+,Ni2+ and Cu2+ doped PMT can significantly improve the electrical properties of polymers.The PMT-Ni specific capacitance reached a maximum value of 80.5F/g and the retention rate after the 1000 cycles was 76.1%.(2)PMT-Ni was optimized by process parameters,such as:the molar ratio of FeCl3-Mt,the molar ratio of 3-Mt/NiCl2,polymerization temperature and polymerization time during the chemical oxidation polymerization.The effects of these parameters on the structures,morphologies and electrochemical properties of products were studied.The results show that:the polymer has a larger surface area when the molar ratio of FeCl3/3-Mt/NiCl2 was 4:1:1.5,the polymerization temperature was 20 ℃ and the polymerization time was 6h.The specific capacitance reached the highest value of 91.4F/g at a current density of 0.2A/g and a retention rate of 80%after 1000 cycles.(3)PEDOT-Ni/graphene nanocomposites marked as GO/PEDOT-Ni and GO-Th-PEDOT-Ni were synthesized by PEDOT-Ni with GO and functionalized GO-Th,respectively.The effects of these parameters on the structures,morphologies and electrochemical properties of products were studied.The results show that:the electrochemical properties of GO-Th-PEDOT-Ni nanocomposites were the best.The specific capacitance reached the highest value of 163.5F/g at a current density of 0.2A/g and a retention rate of 91.6%after 1000 cycles.(4)PEDOT-Ni/carbon nanofibers nanocomposites marked as CNFs/PEDOT-Ni and rGONFs/PEDOT-Ni were synthesized by PEDOT-Ni with CNFs and rGONFs,respectively.The effects of these parameters on the structures,morphologies and electrochemical properties of products were studied.The results show that:the electrochemical properties of rGONFs/PEDOT-Ni nanocomposites were the best.The specific capacitance reached the highest value of 131.2F/g at a current density of 0.2A/g and a retention rate of 95.5%after 1000 cycles.