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Study On Synthesis And Electrochemical Performance Of Manganese Dioxide As Electrode Materials For Supercapacitor

Posted on:2014-02-13Degree:MasterType:Thesis
Country:ChinaCandidate:Y YangFull Text:PDF
GTID:2232330395497811Subject:Condensed matter physics
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Supercapacitor, also known as electrochemical capacitor or gold capacitor, is anew type of energy storage device with high power density, long cycle life, and hasgood application prospects in the field of electric vehicles and hybrid vehicles.Research on electrode material is one of the effective ways to improve thesupercapacitor performance. Common activated carbon-based supercapacitor is oflow energy density and high self-discharge current; supercapacitor using Ru, Ir, orother transition metal for is of high cost and likely to cause environent pollution; andother supercapacitor electrode material is still in the research and development stage.Obviously, each supercapacitor electrode material has its own advantages anddisadvantages. Current scientific research is mainly concentrated on two aspects:improvement of the synthesis method and synthesis of several materials, in order toenhance specific capacitance, cycle performance and impedance of the supercapacitor.Promoting the development and application of new energy resource, alleviating thepressure of environmental pollution and improving the energy efficiency of humansociety, Research on supercapacitor electrode material is a very meaningful work.Because of its low cost, environmental-friendly and good electrochemicalperformance, MnO2is considered to be a very promising electrode material forsupercapacitor. Since the first work on synthesis and electrochemical properties ofnano-MnO2have been done by Lee and Goodenough in1999, using nano-MnO2aselectrode material of supercapacitor has been researched thoroughly.In this thesis, the hydrothermal synthesis method was used to study the influenceof synthesis conditions on the electrochemical performance. SEM, XRD and othermeans were used to analyze the material morphology, cyclic voltammetry,charge-discharge cycles and alternating current impedance and other means were usedto characterize the electrochemical properties of the material. Meanwhile, the paperused chemically compounding method to prepared AC/MnO2supercapacitor electrodematerial and studied the impact of different doping ratio on the capacitor performance and cycle performance on the compound material. The main contents are as follows;1. Use MnSO4as reducing agent of KMnO4to prepare MnO2, and study theimpact of heat treatment on MnO2polymorphs by changing the heat treatingtemperature. Compare the electrochemical performance of two MnO2polymorphs.2. Study the impact of pH value of reaction solution on the morphology of theproduct. Explore the impact of specific surface area of the material on its capacitanceperformance.3. Study the impact of heat treatment time on the degree of crystallinity andspecific surface area, and by comparing electrochemical performance of products,identify the most suitable heat treatment time.4. Hydrothermally deposit MnO2on the surface of activated carbon to prepareAC/MnO2composite electrode material. Use SEM and BET specific surface area testto study the morphology of the composites. Use electrochemical testing method tostudy capacitor performance and cycle performance of the composites. Compare theelectrochemical performance of different AC/MnO2composite prepared by dopingratio.
Keywords/Search Tags:upercapacitor, electrochemical, new energy resource, manganese dioxide, composite material
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