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Preparation of Manganese Dioxide and Study on Its Properties as Electrode Material in Electrochemical Capacitors

Author: SunLiJuan
Tutor: ShaoGuangJie
School: Yanshan University
Course: Applied Chemistry
Keywords: Electrochemical capacitors Manganese dioxide Sol - gel method . Liquid precipitation Doping
CLC: TM53
Type: Master's thesis
Year: 2006
Downloads: 384
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Abstract

Electrochemical capacitors is a significant advantage of a new type of energy storage device , the electrode materials are important factors that affect its performance , the manganese dioxide electrode materials is one of the great potential for development , subject prepared by sol - gel two manganese oxide , liquid precipitation to manganese dioxide doped with rare earth elements lanthanum , hoping to get a large specific surface area , good electrochemical performance , higher than the capacity of the manganese dioxide electrode materials . By orthogonal test , single factor experiments and comparative analysis of test and experimental methods , the sol - gel and liquid precipitation process parameters on the organizational structure and electrochemical properties of manganese dioxide . Experimental methods of chemical analysis , scanning electron microscopy , X -ray diffraction analysis of the organizational structure and morphology of the manganese dioxide , by cyclic voltammetry , galvanostatic charge-discharge and self- discharge test methods such as analysis of the electrochemical properties of the manganese dioxide . Experimental sol - gel prepared manganese dioxide optimal parameters : n ( citric acid ) : n ( manganese acetate ) = 0.5:1 , C0 = 0.1 mol L -1 , pH ≈ 6 , the reaction temperature approximately 60 ° C , and calcined at 350 ° C for 3 hours and the temperature acidified by sulfuric acid . Prepared manganese dioxide particles smaller than the large surface area , capacitance characteristics , high cycle stability ; specific capacitance C = 159.5 F · g ^{-1 ( Id = 5 mA ) , with the discharge current increases , some attenuation than the capacity of the large current discharge performance needs to be improved . Prepared by the process of liquid precipitation has not adjusted to pH speculated MnO _1.88, MnO _1.88 better than MnO ₂ the electrochemical performance . MnO _1.88 doped rare earth elements La, La in the form of ions embedded in the lattice of manganese dioxide . Doped manganese dioxide electrode showed good capacitance characteristics and power characteristics . The doping of the different proportions of the electrochemical properties of the manganese dioxide is greater impact when Mn: La doping ratio of 5:1 (molar ratio ) , and manganese dioxide electrode has better capacitance characteristics ; with the charge and discharge shows the good performance of large current discharge current increases, smaller than the capacity of the capacitor attenuation ; lanthanum-doped electrode loop stability .}

Preparation of Manganese Dioxide and Study on Its Properties as Electrode Material in Electrochemical Capacitors

Abstract

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