Porous-anodic-alumina-templated Ta-Nb-alloy oxide coatings via the magnetron-sputtering anodizing as novel 3D nanostructured electrodes for energy-storage applications
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Date
2024-06-26
Authors
Mozalev, Alexander
Bendová, Mária
Gispert-Guirado, Francesc
Llobet, Eduard
Habazaki, Hiroki
ORCID
0000-0002-9505-5359Advisor
Referee
Mark
Journal Title
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Volume Title
Publisher
Elsevier
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Abstract
The Ta-Nb thin alloy films were magnetron sputter-deposited over a low-aspect-ratio nanoporous anodic-alumina template formed in 0.05 M tartaric acid solution at 250 V and modified by the pore-widening technique to enlarge the pores up to 500 nm. The alloy coated the pores evenly, thus forming a 3D continuous conducting nanofilm on the template. Partially anodizing the templated alloy in a borate buffer solution of pH 7.5 generated a compact amorphous mixed-oxide anodic film thickening proportionally to the applied voltage. An unusual two-layered structure with a sharp electrical interface revealed in the 3D oxide films anodized to 30–130 V, comprising a low-resistivity layer superimposed on the high-resistivity layer, is explained by an immobile negative space charge in the outer film part. The air-annealing at moderate temperatures releases the space charge and transforms the two layers into a high-resistivity single layer having substantially improved dielectric properties and thermostable (up to 250 deg) capacitance of 1.2 F cm2 achieved for the film anodized to practical 50 V. The 3D films having up to 4.5 times enlarged effective surface area can be utilized as novel metal/oxide nanostructured electrodes for electrolytic microcapacitors suitable for classical electronic circuits and energy-storage applications.
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Citation
SURFACE & COATINGS TECHNOLOGY. 2024, vol. 489, issue 1, p. 1-14.
https://www.sciencedirect.com/science/article/pii/S025789722400673X
https://www.sciencedirect.com/science/article/pii/S025789722400673X
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Peer-reviewed
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en