Electrochemical mechanics of metal thin films : charge-induced reversible surface stress for actuation

The intrinsic charge-induced surface stress of Ni thin films during electrochemical reactions with an alkaline electrolyte is measured in situ. Surface stresses induced by H absorption/desorption, α-Ni(OH)2 formation, capacitive double-layer charging, the α- to β-Ni(OH)2 transformation, and β-Ni(OH)2/β-NiOOH redox reactions are identified, and each provided additive contributions to the overall stress state. Surface stresses are magnified in high-surface-area nanoporous Ni because local stress-relaxation mechanisms are restricted when compared to a smooth Ni film. Ni film reversible tensile/compressive surface stresses correlate with anodic/cathodic potential scanning but with an opposite trend to that of a less reactive Au film. Surface stresses in the Ni films are up to 40 times that of Au films and suggest the possibility of using controlled surface-stress generation for electrochemical actuation.

Subjects

charge-induced surface stress

electrocapillaries

electrochemical actuators

metal thin films

nanoporous metals

DDC Class

000: Allgemeines, Wissenschaft

Funding(s)

Projekt DEAL

Publication version

publishedVersion

Lizenz

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

Name

aelm.201900364.pdf

Size

4.72 MB

Format

Adobe PDF

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Electrochemical mechanics of metal thin films : charge-induced reversible surface stress for actuation