Monolithic MXene composites with multi-responsive actuating and energy-storage multi-functions

Soft robots are developing in the direction of integration, miniaturization and multi-functionality, so various devices (power sources, sensors, actuators, etc.) are becoming more and more integrated. Actuators and energy storage modules are two important components, and the integration of these two modules is critical to the development of soft robots. However, how to integrate actuating and energy-storage functions in a single device is still a challenge. Here, we propose a “one-for-all” strategy to prepare devices with multi-functions using a monolithic MXene/biaxially-oriented polypropylene (BOPP) composite film. On one hand, the obtained bilayer film works as an actuator, which can be driven by light or electricity. The maximal bending curvature is up to 1.51 cm −1 and has no significant decay after 600 cycles. On the other hand, the BOPP can overcome the brittleness of MXene thin film and promote its application in flexible supercapacitors. The areal capacitance of the electrode is 358.2 mF cm −2 (238.8 F g −1 ) at 0.1 mA cm −2 . Furthermore, a smart gripper with indication function, combining both actuating and energy-storage functions, is successfully fabricated, which can indicate the working state of the gripper. The demonstration not only can provide a new design idea for greatly broadening the application field of MXene composite, but also can inspire more researches for smart devices, highlighting the feasibility of the “one-for-all” idea.