Abstract

Contrary to the electrochemical energy storage in Pd nanofilms challenged by diffusion limitations, extensive metal–hydrogen interactions in Pd-based metallic glasses result from their grain-free structure and presence of free volume. This contribution investigates the kinetics of hydrogen–metal interactions in gold-containing Pd-based metallic glass (MG) and crystalline Pd nanofilms for two different pore architectures and nonporous substrates. Fully amorphous MGs obtained by physical vapor deposition (PVD) co-sputtering are electrochemically hydrogenated by chronoamperometry. High-resolution (scanning) transmission electron microscopy and corresponding energy-dispersive X-ray analysis after hydrogenation corroborate the existence of several nanometer-sized crystals homogeneously dispersed throughout the matrix. These nanocrystals are induced by PdHx formation, which was confirmed by depth-resolved X-ray photoelectron spectroscopy, indicating an oxide-free inner layer of the nanofilm. With a larger pore diameter and spacing in the substrate (Pore40), the MG attains a frequency-independent impedance at low frequencies (∼500 Hz) with very high Bode magnitude stability accounting for enhanced ionic diffusion. On the contrary, on a substrate with a smaller pore diameter and spacing (Pore25), the MG shows a larger low-frequency (0.1 Hz) capacitance, linked to enhanced ionic transfer in the near-DC region. Hence, the nanoporosity of amorphous and crystalline metallic materials can be systematically adjusted depending on AC- and DC-type applications.
OriginalspracheEnglisch
Seiten (von - bis)42613-42623
Seitenumfang11
FachzeitschriftACS Applied Materials and Interfaces
Jahrgang13.2021
Ausgabenummer36
DOIs
PublikationsstatusVeröffentlicht - 15 Sept. 2021

Bibliographische Notiz

Funding Information:
B.S. conceptualized the idea, developed the methodology, analyzed the data, and wrote the original manuscript. Y.P.I. carried out laboratory research, analyzed the data, reviewed and edited the manuscript, and supported the project by funding. T.K. developed the methodology, carried out laboratory research, and reviewed and edited the manuscript. B.P. produced samples and reviewed and edited the manuscript. S.D. carried out laboratory research, analyzed the data, and reviewed and edited the manuscript. M.M. carried out laboratory research, analyzed the data, and reviewed and edited the manuscript. M.O. reviewed and edited the manuscript. A.L.G. reviewed and edited the manuscript and supported the project by funding. A.S.S. analyzed the data and wrote the original manuscript. J.E. reviewed and edited the manuscript and supported the project by funding.

Publisher Copyright:
© 2021 American Chemical Society

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