Electrochemical Actuators with Multicolor Changes and Multidirectional Actuation

Abstract Electrochemical (EC) actuators have garnered significant attention in recent years, yet there are still some critical challenges to limit their application range, such as responsive time, multifunctionality, and actuating direction. Herein, an EC actuator with a back‐to‐back structure is fabricated by stacking two membranes with bilayer V2O5 nanowires/single‐walled carbon nanotubes (V2O5 NWs/SWCNTs) networks, and shows a synchronous high actuation amplitude (about ±9.7 mm, ±28.4°) and multiple color changes. In this back‐to‐back structure, the inactive SWCNTs layer is used as a conductive current collector, and the bilayer network is attached to a porous polymer membrane. The dual‐responsive processes of V2O5 nanowires (V2O5 NWs) actuation films and actuators are also deeply investigated through in situ EC X‐ray diffraction and Raman spectroscopy. The results show that the EC actuation of the V2O5 NWs/SWCNTs film is highly related to the redox behavior of the pseudocapacitive V2O5 NWs layer. At last, both V2O5 NWs and W18O49 nanowires (W18O49 NWs)‐based EC actuators are constructed to demonstrate the multicolor changes and multidirectional actuation induced by the opposite lattice changes of V2O5 NWs and W18O49 NWs during ionic de‐/intercalation, guiding the design of multifunctional EC actuators in the future.