Microstructural Characterization and Electrochemical Properties of RuO₂ Thin Film Electrodes Prepared by Reactive Radio-Frequency Magnetron Sputtering

Abstract

Ruthenium dioxide films were prepared by radio-frequency magnetron sputtering onto Si and Ti substrates. Films of different thicknesses (100-500 nm) were synthesized at substrate temperatures of 40, 350, and 450 °C. Their composition has been studied by Rutherford backscattering spectrometry, elastic recoil detection, and ion beam nuclear reaction analysis. Scanning electron microscopy and wide-angle X-ray scattering have been used for studying the surface texture of the samples and for their microstructural characterization, respectively. The electrochemical characterization by cyclic voltammetry has shown that, despite the high physical density of the films, compared with that obtained by the thermochemical methods, they exhibit large charge-storage capacities. For the materials synthesized at 350-450 °C, an explanation of these results has been sought in specific features of the RuO 2 rutile-type cell and columnar texture of the oxide film. The much higher capacity of the films synthesized at 40 °C would be rather due to a poor sintering of the oxide phase. Study of the chlorine evolution reaction in the samples prepared at 350 and 450 °C points to a Volmer-Tafel mechanism, with a chemical desorption rate-determining step, and significant radical intermediate coverage. Films deposited at 40 °C exhibited an unsatisfactory wear resistance under the anodic polarization required for the chlorine evolution reaction investigation.

Fabrication of manganese oxide electrodes by radio frequency sputtering for electrochemical capacitors

“…7a, 8). A similar result has been published in previous literature [3,30,31]. However, at volume flow rates of oxygen in the range 5-7.5 sccm, the amounts of trivalent manganese oxide (or the valences of manganese) were almost the same due to excess oxygen and the mass specific capacitance decreased because of decreasing surface roughness (see Table 1 and Figs.…”

“…The lower the kinetic energy, the lower the mobility on the surface of the substrate for particles (ions and reflected neutrals), and the higher the surface roughness (see Fig. 3, i.e., there is an increase in the height of the surviving particles in a particle-migration coalescence process), thus leading to higher mass specific capacitance (a similar result has been published in previous literature [30,31]). However, mass specific capacitance declined at sputtering pressure in the range 20-30 mTorr.…”

“…In addition, ruthenium oxide films were deposited on Si and Ti substrates by reactive radio frequency (RF) magnetron sputtering and the total anodic voltammetric charges increased with increasing roughness factor [30]. Since the highly rough surface should possess the high surface area, the mass specific capacitance also increased with increasing the roughness factor for manganese oxide [31].…”

Electrophoretic deposition (EPD) of hydrous ruthenium oxides with PTFE and their supercapacitor performances

“…For this, various methods have been utilized for the preparation of ruthenium oxide electrodes such as: electrostatic spray deposition (ESD) [4,5], synthesis of ruthenium oxide aerogels [6], RF magnetron sputtering [7], electrodeposition [8,9], and thermal decomposition of ethanol precursors [10].…”

Wet film application techniques and their effects on the stability of RuO2–TiO2 coated titanium anodes

“…Titanium substrates were attached to a titanium rod by spot welding for dip coating. The substrate was then fully immersed into the precursor Application Pulsed laser deposition [14] Sputtering [15] Metal organic CVD [16][17][18] RF magnetron sputtering [19] Sol-gel [9,[20][21][22] Electrodeposition [23][24][25] Spray pyrolysis [26] Rapid thermal decomposition [27] Adams fusion method [28] Precursor solution Polyol method [28] Pechini method-Polymeric precursor [11,12,29] solution and withdrawn at a constant rate of 0.18 m min -1 . Spin coated samples were prepared by using a Laurells WS-400A-6NPP/LITE single wafer spin coater.…”