A synergistic Ti3C2T /PPy bilayer electrochemical actuator

• A simple electrodeposition method deposits PPy on the surface of Ti 3 C 2 T x to prepare a Ti 3 C 2 T x /PPy bilayer film. • The curvature change of Ti 3 C 2 T x /PPy bilayer film was improved by 57% (at 5 mV/s) in aqueous 1 M LiClO 4 compared to the pure PPy film. • After 10,000 cycles, the actuation performance of Ti 3 C 2 T x /PPy bilayer film can still maintain 69.2% of the initial performance. Electrochemical actuators are devices that directly convert electrical energy into mechanical energy and have a wide range of applications. MXenes have high energy density, excellent rate performance, high electronic conductivity, strong mechanical strength, and can store ions through fast intercalation mechanism, making it a promising material for actuator applications. However, the restacking of MXenes layers limits ion percolation and thus limits the actuation performance. Polypyrrole (PPy) has a large volume deformation during its redox reaction process, but its low electrical conductivity and weak mechanical strength limit its practical application. Here, we logically designed an electrochemical actuator with Ti 3 C 2 T x /PPy bilayer film as the electrode, and the Ti 3 C 2 T x layer effectively improved the electrical conductivity of Ti 3 C 2 T x /PPy and acted as the same time as current collector, co-actuation, and conductive additive, effectively accelerating the redox reaction rate of the PPy layer and increasing the performance. The curvature change of Ti 3 C 2 T x /PPy bilayer film was improved by 57% (at 5 mV/s) in aqueous 1 M LiClO 4 compared to the pure PPy film. After 10,000 cycles, 69.2% of the initial actuation performance can still be maintained. This research proves that this electrode structure design is feasible to improve the performance of actuators.