Metal-Organic Framework-Derived Graphitic Nanoribbons Anchored on Graphene for Electroionic Artificial Muscles

Abstract

To achieve large bending displacement and fast response time under ultralow input voltages, as well as improved durability, advanced high-performance ionic actuators still face crucial design challenges that must be resolved. Here, hierarchically porous and unzipped graphitic nanoribbons anchored on graphene as an efficient electrode material for high-performance electroionic artificial muscles are reported. Using controlled solvothermal and pyrolysis methods, nanoarchitectured carbon is derived from a self-templated potassium-based metal-organic frameworks-graphene hybrid. The newly designed ionic actuator demonstrates excellent actuation performance, including large bending displacement (17.4 mm) and a strain difference of 0.51% at 0.5 V AC input, very fast response time (700 ms) at 0.5 V DC input, wide frequency response (0.1-15 Hz), and excellent cycling stability (92%) after 25 000 cycles without any delamination of electrodes under continuous electrical operation. The breakthrough in actuation performance mainly stems from the unzipping of hollow nanorods to hierarchical porous graphitic nanoribbons anchored on graphene with the enlarged surface area, large pore volume, stronger mechanical integrity, and emerging charge storage and transport ability. Further, the electroionic actuator shows promise when applied in the demonstration of a biomimicking Venus flytrap.