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The Electrode Impedance Spectroscopy Analysis Of Containing Ruthenium The Multiple Oxide Capacitor ——RuO2-ZrO2 And RuO2-Al2O3

Posted on:2014-02-05Degree:MasterType:Thesis
Country:ChinaCandidate:H D LuFull Text:PDF
GTID:2272330461473389Subject:Materials science
Abstract/Summary:PDF Full Text Request
With the development of social economy, people are paying more attention on green power and environmental protection. Electrochemical supercapacitor is a new energy storage element, other than the new energy storage battery and the electrostatic capacitance, with a higher power density, higher energy density than the normal battery. But there is not much literature about its mechanism of action and how to improve the property. In this work, for the RuO2-ZrO2 and RuO2-Al2O3 electrodes, the capacitive performance, working mechanism and ways to improve the property were investigated by using the method of cyclic voltammetry, AC impedance, XRD experiments.The results of XRD experiments indicate that the addition of Zr element affects the structure of the electrode, and then have a significant impact on the performance of the capacitors. For RuO2-ZrO2 electrodes, the AC impedance test and the fitting of circuit diagram compared with the method of cyclic voltammetry, also separately analysis the outer activity and the inner activity indicated that with the increasing content of the Zr component, the specific capacitance of coating presents a trend of climbing up and then declining. When the Zr content in the range of 40mol%-60mol%, the capacitance performance shows best. The main reason is the addition of the Zr element, leading to the existence of RuO2 in the coatings with the Rutile and the amorphous oxide simultaneously. And let the outer activity and the inner activity have a high level. The proton conductivity and electronic conductivity together to improve the electrocatalytic activity. A great influence by heat treatment conditions on the structure of the binary composite electrode. As the temperature increases, RuO2 crystallization degree becomes higher in the coating. The proton conductivity and electronic conductivity are affected also. Specific surface area decreased, The specific capacitance of the electrode decreased the same as electrocatalytic activity.The choice of ingredients is also very important.In the work, for Ru-Al electrode coated electrodes. The AC impedance test and the fitting of circuit diagram compared with the method of cyclic voltammetry showed that the element Al can make the resistance of the electrode coating is significantly reduced, also promote the electronic conduction. In the same time, he structure of the electrode becomes loose, to promote the proton conductivity, suitable for the high-power charging and discharging. When excessive amount of Al added, eventually because of the thickness of the electrode coating become thicker, so as the resistance of the coating increasingly, lead to the capacitance decreases.This paper is also calculated electrode surface active sites density by EIS. And compared with the density of active sites tested by commonly used cyclic voltammetry the same as change in electricity consumption. The results show that use EIS method to calculate the density of active sites trend closer to the electrode voltammetry electricity. Indicating the accuracy of the AC impedance method for calculating the points of the activity of the electrode.
Keywords/Search Tags:Supercapacitor, Electrocatalysis, Electrochemical Impedance Spectroscopy, Structure, Conductivity
PDF Full Text Request
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