Choosing the metal oxide for an electro-chemo-mechanical actuator working body

The term electro-chemo-mechanical (ECM) effect describes mechanical deformation driven by an electro-chemical reaction. Recently, an all-solid-state ECM device operating at room temperature was demonstrated. The device comprised a 20 mol% Gd-doped ceria (20GDC) self-supported electrolyte membrane placed between two mixed ionic/electronic conducting (MIEC) working bodies (WBs) constructed with TiOx/20GDC nanocomposites. Actuation derived from volume change occurring upon oxidation/reduction of the WB. This raised the question of whether or not metal oxides other than TiOx could be valuable components in MIEC nanocomposites func-tioning as WBs in ECM actuation. Here we examine the microstructure, crystal phase, oxidation state, chemical composition and ECM functionality of V-, Nb-, Mo-, Cu-and Ag-oxide/20GDC composite WBs prepared by co-sputtering. Of these, only the V-based composite was shown to be suitable for ECM actuation. According to X-ray absorption spectroscopy, the composition of the nanocomposite corresponds to VOx/20GDC. Electrical characterization suggests that the formation of several coexisting VOx nano-oxide phases is responsible for the longer response times as compared to TiOx/20GDC WBs. ECM actuation demonstrated in the V-based system does indicate that composite WB based ECM is not unique to Ti and that this type of actuation constitutes a significant contribution to development of microelectromechanical systems.

Automated summary

An all-solid-state ECM device operating at room temperature was demonstrated recently. It was discovered that metal oxides other than TiOx can also be valuable components in MIEC nanocomposites functioning as working bodies (WBs) in ECM actuation. However, only the V-based composite was suitable for ECM actuation, while the other oxides showed longer response times.