Tailoring the nanostructures of electrochemical actuators for fast response and large deformation

Electrochemical actuators (EAs) can effectively convert electric energy to mechanical energy through chemical reactions. However, the response rate and deformability, two of the crucial and antithetic factors in EA studies, can both hardly be improved just by developing or hybridizing different kinds of materials. In this work, this challenge is overcome through tailoring the nanostructures of EAs. A 3D nanoporous structure formed by aggregating spherical MoS₂ nanoparticles (NPs) is reported. The NP-aggregated nanoporous structure not only provides a fast ion-migration process but also ensures strong mechanical strength. Experiments show that the voltage-dependent response rate and curvature amplitude respectively approach 0.015 mm^-1·s^-1·V^-1 and 0.244 mm^-1·V^-1, which simultaneously exceed those of most EAs. A continuous energy density of 14 kJ·m^-3, almost double that of mammalian muscle, enables the EA to rotate a stainless-steel weight which is over 550 times heavier than itself. By opening a new way to improve EAs' comprehensive performance, this research propels their potential applications in microrobotics and mini-medical devices.