We optimized various anodization strategies,[1-4] in terms of
electrolyte composition and anodization temperature, time and
voltage, to enable self-organizing growth of 1D oxide layers on
a series of metal substrates including Ti, W, Nb, Mo and MoTa
alloys. The resulting nanostructured oxides provided promising
performances when tested as electrode materials for batteries
(Li ion batteries) or supercapacitors.[6-12]
For such 1D structures, performance enhancement in energy storage applications was accomplished through different strategies including (i) morphology control, such as in spaced nanotubes to provide large surface area and inter-tube lateral separation to incorporate additional functional materials or accommodate lattice expansion caused by ion intercalation,[6,7] (ii) conductivity tuning, e.g. in thermally reduced semimetallic core/shell nanotubes featuring improved electron transport properties, (iii) alloying effects, as in the case of MoTa oxide nanotubes where alloying provides superior electrochemical stability against corrosion, and (iv) surface functionalization, e.g. by thermal phosphidation to coat Mo oxide nanotubes with nm thick conformal MoP films providing enhanced conductivity and hydrophilicity.
Some literature citations:
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 P. Roy, S. Berger, P. Schmuki, Angew. Chemie Int. Ed. 2011, 50, 2904.
 H. Tsuchiya, P. Schmuki, Nanoscale 2020, 12, 8119.
 F. Riboni, N. T. Nguyen, S. So, P. Schmuki, Nanoscale Horiz. 2016, 1, 445.
 G. Cha, S. Mohajernia, N. T. Nguyen, A. Mazare, N. Denisov, I. Hwang, P. Schmuki, Adv. Energy Mater. 2020, 10, 1903448.
 N. T. Nguyen, S. Ozkan, I. Hwang, X. Zhou, P. Schmuki, J. Mater. Chem. A 2017, 5, 1895.
 S. Ozkan, N. T. Nguyen, I. Hwang, A. Mazare, P. Schmuki, Small 2017, 13, 1603821.
 K. K. Upadhyay, M. Altomare, S. Eugénio, P. Schmuki, T. M. Silva, M. F. Montemor, Electrochim. Acta 2017, 232, 192.
 K. K. Upadhyay, G. Cha, H. Hildebrand, P. Schmuki, T. M. Silva, M. F. Montemor, M. Altomare, Electrochim. Acta 2018, 281, 725.
 B. Jin, S. Hejazi, H. Chu, S. Mohajernia, N. Nhat Truong, M. Yang, M. Altomare, P. Schmuki, Appl. Mater. Today 2019, 17, 227.
 B. Jin, S. Hejazi, F. Pyczak, M. Oehring, S. Mohajernia, S. Kment, O. Tomanec, R. Zboril, N. T. Nguyen, M. Yang, P. Schmuki, ACS Appl. Mater. Interfaces 2019, 11, 45665.
 S. Mohajernia, S. Hejazi, A. Mazare, N. T. Nguyen, I. Hwang, S. Kment, G. Zoppellaro, O. Tomanec, R. Zboril, P. Schmuki, Mater. Today Energy 2017, 6, 46.