Highly conductive ion channels enable flexible actuators for robotic applications

Abstract

An ionic actuator assembled with an electrolyte and an electrode is an important building block for soft robotics owing to the merits of flexibility, stability and lightweight. However, unsatisfactory ion transfer inside electrolytes impedes the practical application of ionic actuators, as they lack effective structure engineering strategy for achieving ion channels within electrolytes. Herein, we report a composite electrolyte with superior electrical and mechanical properties for use in high-performance ionic actuators. Perpendicular ion channels were formed in the electrolyte via phase separation of the composite polymer networks. As a result, the electrolyte displays 46 times higher conductivity than the contrast sample and a large tensile strain of 41.2% with a breaking modulus of 1.5 MPa. The as-fabricated soft actuator delivered excellent actuation properties, such as large actuating deformation (20 mm at 2.5 V, 0.1 Hz), high-frequency response (0.1–10 Hz) and long cyclic life (15 000 cycles in air). Furthermore, several soft robotics were developed based on our actuators to demonstrate their practical application potential, such as walking legs, bird wings, blooming flowers and moving fingers. This study provides new insights into the structure design of highly conductive flexible electrolytes for electrochemical soft devices.