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Research And Application Of Supercapacitors Of Aqueous Electrolytes

Posted on:2006-03-31Degree:MasterType:Thesis
Country:ChinaCandidate:J L YinFull Text:PDF
GTID:2132360155968844Subject:Applied Chemistry
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Supercapacitors are new energy storage components between batteries and electrostatic capacitors, which have higher power density and longer cycle life than batteries, and can be charged within a short time. They can be used as assistant power sources for electric components, power sources for small electrical equipments or pulse power sources. In addition, they can be used as driving system of electric vehicles with batteries.Supercapacitors can be classified electric double layer capacitors and pseudo-capacitors according to their working principles. Because electrode materials and electrolytes are important factors, we conducted a series of experiments to research on actived carbon, MnO2, aqueous electrolytes, simulation of hybrid driving system with the aids of the measure methods such as cyclic voltammetric measurements(CV), impedance spectrum, constant charge/ discharge measurements, X-rays diffraction(XRD), leakage current, and so on.Firstly, actived carbon electrodes were actived by chemical methods and modified by Co2+. The result is that the performances of actived carbon actived by 65% HNO3 or 98% H2SO4 are better than that of without disposition, and actived carbon electrode modified by Co2+ has electric double layer capacitors are enhanced, the capacitance of single electrode is 158.24F/g and is 26.8% higher than that of without modified when C:Co=13:1, and the capacitors of actived carbons modified by Co2+ have longer cycle life whose capacitance has been kept more than 91% after 1000 cycles. Secondly, we prepared MnO2, by four methods and adulterated CoOOH into MO2 power. The result is that the performance of the MnO2 electrodes directly adulterated CoOOH is worse.Thirdly, we found (NH4)2SO4 electrolytes is the best electrolyte for capacitors in the aqueous electrolytes according to a series of researches. The same time. Li2SO4 and Li2CO3 as additives were put into (NH4)2SO4 electrolyte. The result is that Li2SO4 and Li2CO3 added into (NH4)2SO4 electrolyte canimprove the capacitance, and the capacitance of adding U2CO3 is higher than that of adding U2SO4, especially for the hybrid electrochemical capacitors. When 0.368mol/L U2CO3 was added into (NH^SC^ electrolyte, the specific capacitance would be the highest and the capacitors had longer cycle life. Finally, when we used supercapacitors and batteries as the hybrid driving system, we found that the time of discharge for batteries was longer. This research will ground for the research on the power sources of hybrid electric vehicles.
Keywords/Search Tags:Supercapacitor, Actived carbon, MnO2, (NH4)2SO4, Hybrid driving system
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