Research On Preparation And Capacitive Properties Of Conductive Polyaniline-base Electrode Materials In Supercapacitors

Firstly, conductive polyainiline (PANi) were prepared by three kinds of chemicaloxidation methods, i.e. solution, emulsion, microemulsion, and electrochemical methodrespectively in this paper. FT-IR, SEM, TGA and conductivity test were used tocharacterize the chemical structures, micro morphologies and the relative physicalproperties of the PANi. The capacitive properties of conductive PANi in1M H2SO4electrolyte solution were studied by constant current charging-discharging and cyclicvoltammetry technologies. It has shown that all PANi products from differentpolymerization methods possess of the chemical structure with emeraldine base(EB),and the corresponding morphologies are globular flower shape with coarse surface,reunion loose and irregular cotton-like form, reunion loose pockety nano wire andhomogeneous nano wire structure respectively. It has been found that the preparationmethod of the PANi electrode materials has great effect on their thermostability,conductivity and charging-discharging performance of the capacitor assembled by theseelectrode materials. The thermostability falls for these PANi electrode materials fromdifferent methods, i.e. electrochemical method, solution method, microemulsion methodand emulsion method, and the corresponding conductivities of PANi are11.6,2.3,1.8and12.4S/cm respectively. We are capable of finding the fact that the redoxreversibility, specific capacitance, energy density and coulombic efficiency of the PANielectrode specimens prepared by solution chemical oxidation method andelectrochemical method are the best among all polymerization methods, and theirspecific capacitance can reach395.8Fg-1and375.7Fg-1respectively.Besides, this paper also studied the capacitive properties of PANi as the electrodeprepared by solution and electrochemical method respectively in1M HCl and1M H2SO4electrolyte solution respectively by electrochemical workstation. The results showedthat the specific capacitance,energy density and coulombic efficiency of the conductivePANi made by solution method are higher in1M HCl than that in1M H2SO4,but a opposite result was obtained for PANi from electrochemical method. The specificcapacitance of conductive PANi prepared using solution method in1M HCl and1MH2SO4are302.43Fg-1,270Fg-1respectively at0.5Ag-1, and the corresponding ones are312.88Fg-1,375.66Fg-1respectively for the conductive PANi prepared byelectrochemical method. In the same electrolyte, the conductive PANi prepared byelectrochemical method has higher specific capacitance and energy density than that bysolution method, while the coulombic efficiency of the latter is slight higher than theformer’s.Finally, PANi/S composite was also prepared by solution oxidation polymerizationmethod, and a preliminary investigation on the capacitive performance of asupercapacitor made by PANi/S composite electrode in1M HCl solution was carriedout in this paper. It has been found that the initial discharge specific capacitance andenergy density of the composite can reach up to2871.83Fg-1and516.93Wh.kg-1respectively at0.5Ag-1.