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Wang J.,Xi'an Jiaotong University | Wang J.,China Zhenhua Group Xinyun Electronic Computer and Dev. Co. | Xu Y.,Xi'an Jiaotong University | Ma J.,China Zhenhua Group Xinyun Electronic Computer and Dev. Co. | And 5 more authors.
Xiyou Jinshu Cailiao Yu Gongcheng/Rare Metal Materials and Engineering | Year: 2012

Nanostructured hydrous ruthenium oxide (RuO 2·xH 2O) was directly deposited on tantalum (Ta) substrates by cyclic voltammetry (CV) technology in RuCl 3·xH 2O aqueous solutions. The growth mechanism, revealed by energy dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM) techniques, is that Ru 3+ ions are reduced to nanostructured ruthenium (Ru) particles during negative potential scanning, then are oxidized to RuO 2·xH 2O granules (also in nanometers) during the following positive scanning. The unique nanometer structure of RuO 2·xH 2O, rather than the conventional "mud-cracked" structure, enable itself a high specific capacitance of 730 F·g -1 at a scanning rate of 50 mV·s -1 and a very fast charging/discharging ability. The specific capacitance is still up to 700 F·g -1 when the oxide loading is up to 1.2 mg·cm -2. In addition, the capacitance retains about 100% after 100, 000 charging/discharging cycles. All of these indicate that the nanosized RuO 2·xH 2O is an excellent electrode material for energy storage and conversion devices, such as supercapacitors. Copyright © 2012, Northwest Institute for Nonferrous Metal Research. Published by Elsevier BV. All rights reserved.


Liu H.,Central South University | Gan W.,Central South University | Huang B.,China Zhenhua Group Xinyun Electronic Computer and Dev. Co. | Liu J.,Central South University | And 2 more authors.
Xiyou Jinshu Cailiao Yu Gongcheng/Rare Metal Materials and Engineering | Year: 2011

As a good film electrode material for supercapacitor (Ru-Sn)O2 · nH2O film was deposited on tantalum foils with aqueous solution of (Ru-Sn)Clx as reservoir by galvanostatic-differential pulse voltammetry and heat treatment. The surface morphology, phase transition of precursor (Ru-Sn)Clx to amorphous (Ru-Sn)O2 · nH2O and capacitance of the film were studied by scanning electron microscope (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and electrochemical analyzer, respectively. Results show that the precursor (Ru-Sn)Clx transforms into (Ru-Sn)O2 · nH2O film by the proper heat treatment, and the adhesive force of the film with Ta substrate is improved significantly which is measured to be 12.3 MPa. The binding force is improved with addition of SnCl2 into solution. With more addition of SnCl2, the surface mass per unit area is increased; the capacitance of the film per unit area is increased at first and then decreased gradually with a maximum value of 1.9 F/cm2 while the special capacitance drops continuously.

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