Authors: Changzhou Yuan Hui Dou Bo Gao Linghao Su Xiaogang Zhang
Publish Date: 2008/04/09
Volume: 12, Issue: 12, Pages: 1645-1652
Abstract
A mild hydrothermal process is applied to synthesize hydrous ruthenium–tin binary oxides Ru07Sn03O2·nH2O with good capacitive performance in alkaline system Then a symmetric electrochemical capacitor EC is fabricated based on the assynthesized Ru07Sn03O2·nH2O material and 1 M KOH aqueous electrolyte Electrochemical performance of the symmetric EC is investigated by cyclic voltammetry galvanostatic charge–discharge and electrochemical impedance spectroscopy tests Electrochemical tests demonstrate that the symmetric EC surprisingly can operate with a high upper cell voltage limit of 145 V in 1 M KOH electrolyte Maximum specific capacitance and energy density of the symmetric aqueous EC are approximately 160 F/g and 21 Wh/kg respectively delivered at a current density of 125 A/g And the specific energy density decreases to approximately 15 Wh/kg when the specific power density increases up to approximately 1770 W/kg The promising specific energy and power densities are obtained simultaneously for the unwonted symmetric EC due to its larger operating potential range Moreover the symmetric EC exhibits electrochemical stability with 852 of the initial capacitance over consecutive 1000 cycle numbers
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