All‐Solid‐State Electro‐Chemo‐Mechanical Actuator Operating at Room Temperature

Abstract

Dimensional change in a solid due to electrochemically driven compositional change is termed electro-chemo-mechanical (ECM) coupling. This effect causes mechanical instability in Li-ion batteries and solid oxide fuel cells. Nevertheless, it can generate considerable force and deformation, making it attractive for mechanical actuation. Here a Si-compatible ECM actuator in the form of a 2 mm diameter membrane is demonstrated. Actuation results from oxygen ion transfer between two 0.1 µm thick Ti oxide\Ce 0.8 Gd 0.2 O 1.9 nanocomposite layers separated by a 1.5 µm thick Ce 0.8 Gd 0.2 O 1.9 solid electrolyte. The chemical reaction responsible for stress generation is electrochemical oxidation/reduction in the composites. Under ambient conditions, application of 5 V DC produces actuator response within seconds, generating vertical displacement of several µm with calculated stress ≈3.5 MPa. The membrane actuator preserves its final mechanical state for more than 1 h following voltage removal. These characteristics uniquely suit ECM actuators for room temperature applications in Si-integrated microelectromechanical systems.

Comparative analysis of XANES and EXAFS for local structural characterization of disordered metal oxides

“…In these cases, the results obtained by EXAFS and pre-edge XANES analyses are consistent with each other. The above analysis also suggests that Ti with somewhat different oxidation state shares similar local coordination, which may be a hint to the ability of these composites to undergo rapid oxidation and reduction in the ECM effect (Makagon et al, 2020).…”

“…Nanocomposite thin films were fabricated according to the previously published method (Makagon et al, 2020). Namely, TiGDC20 (GDC20: 20% Gd-doped ceria) composites were deposited by a magnetron co-sputtering method on SiO 2 substrates with a 100 nm Al adhesion layer.…”

“…TiGDC20 composites were recently shown to have exceptionally high oxygen diffusion coefficients at room temperature ('10 À14 cm 2 s À1 ) and reversible oxidation-reduction cycling. This unique property led to the demonstration of an electro-chemo-mechanical (ECM) actuator working at room temperature (Makagon et al, 2020).…”

Chemical lattice strain in nonstoichiometric oxides: an overview

“…173 Further developments of this approach 275 resulted in a MEC actuator prototype capable of micrometer-scale displacement at room temperature. 276 This actuator was made of a 150 nm thick Ce 0.8 Gd 0.2 O 1.9 electrolyte membrane sandwiched between two 100 nm thick composite Ti/Ce 0.8 Gd 0.2 O 1.9 electrodes, or working bodies, which provided mechanical action via their oxidation or reduction under the voltage applied. 276…”

Electro-responsive actuators based on graphene

“… 23 , 24 , 25 , 26 , 27 , 28 , 29 Consequently, ERAs hold great promise for developing e-skins, soft robots, unmanned flight, and in vivo surgery devices. 30 , 31 , 32 , 33 According to different working mechanisms, ERAs can be classified into four kinds, including (1) electrostatic actuation, such as dielectric elastomer actuators, piezoelectric actuators, based on charge interactions 34 , 35 , 36 ; (2) electrothermal actuation that makes use of Joule heating effect induced asymmetric thermal expansion between bi-/multilayer structures 37 , 38 , 39 ; (3) ionic actuation that works through anions/cations induced asymmetric volume change of electrode layers 40 , 41 , 42 ; and (4) electro-hydraulic actuation that integrated power electronics and motor drive. 43 , 44 , 45 Generally, the structure of ERAs is simple, consisting of electrodes, electro-responsive materials, and coupled deformable materials/substrates.…”