Robust metallic actuators based on nanoporous gold rapidly dealloyed from Gold–Nickel precursors

Dealloyed nanoporous gold (np-Au) has applications as oxygen reduction catalysis in Li-air batteries and fuel cells, or as actuators to convert electricity into mechanical energy. However, it faces the challenges of coarsening-induced structure instability, mechanical weakness due to low relative densities, and slow dealloying rates. Here, monolithic np-Au is dealloyed from a single-phase Au25Ni75 solid-solution at a one-order faster dealloying rate, ultra-low residual Ni content, and importantly, one-third more relative density than np-Au dealloyed from conventional Au25Ag75. The small atomic radius and low dealloying potential of the sacrificing element Ni are intrinsically beneficial to fast produce high relative density np-Au, as predicted by a general model for dealloying of binary alloys and validated by experiments. Stable, durable, and reversible actuation of np-Au takes place under cyclic potential triggering in alkaline and acidic electrolytes with negligible coarsening-induced strain-shift. The thermal and mechanical robustness of bulk np-Au is confirmed by two-order slower ligament coarsening rates during annealing at 300 °C and 45 MPa macroscopic yielding strength distinctive from the typical early onset of plastic yielding. This article opens a rich direction to achieve high relative density np-Au which is essential for porous network connectivity, mechanical strength, and nanostructure robustness for electrochemical functionality.

Subjects

charge-induced reversible strain

coarsening

electrochemical actuators

electrochemical dealloying

nanoporous gold

DDC Class

530: Physik

600: Technik

Funding(s)

Projekt DEAL

Funding Organisations

Alexander von Humboldt-Stiftung

Publication version

publishedVersion

Lizenz

https://creativecommons.org/licenses/by-nc/4.0/

Name

Adv Funct Materials - 2021 - Cheng - Robust Metallic Actuators Based on Nanoporous Gold Rapidly Dealloyed from Gold Nickel.pdf

Size

14.66 MB

Format

Adobe PDF

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Robust metallic actuators based on nanoporous gold rapidly dealloyed from Gold–Nickel precursors