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

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 mu m thick Ti oxide\Ce(0.8)Gd(0.2)O(1.9)nanocomposite layers separated by a 1.5 mu m 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 mu m with calculated stress approximate to 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.

Automated summary

ECM coupling, driven by electrochemical compositional changes in solids, can cause mechanical instability in Li-ion batteries and solid oxide fuel cells, but also has potential applications in mechanical actuation for Si-integrated microelectromechanical systems.