Ant-nest-inspired porous structure for MXene composites with high-performance energy-storage and actuating multifunctions

Integrating energy-storage devices (supercapacitors) and shape-deformation devices (actuators) advances the miniaturization and multifunctional development of soft robots. However, soft robots necessitate supercapacitors with high energy-storage performance and actuators with excellent actuation capability. Here, inspired by ant nests, we present a porous structure fabricated by MXene-graphene-methylcellulose (M-GMC) composite, which overcomes the self-stacking of MXene nanosheets and offers a larger specific surface area. The porous structure provides more channels and active sites for electrolyte ions, resulting in high energy storage performance. The areal capacitance of the M-GMC electrode reaches up to 787.9 mF center dot cm-2, significantly superior to that of the pristine MXene electrode (449.1 mF center dot cm-2). Moreover, the M-GMC/polyethylene bilayer composites with energy storage and multi-responsive actuation functions are developed. The M-GMC is used as the electrode and the polyethylene is used as the encapsulation layer of the quasi-solid-state supercapacitor. Meanwhile, the actuators fabricated by the bilayer composites can be driven by light or low voltage (<= 9 V). The maximum bending curvature is up to 5.11 cm-1. Finally, a smart gripper and a fully encapsulated smart integrated circuit based on the M-GMC/polyethylene are designed. The smart gripper enables programmable control with multi-stage deformations. The applications realize the intelligence and miniaturization of soft robots. The ant-nest-inspired M-GMC composites would provide a promising development strategy for soft robots and smart integrated devices.