Optimization of Core-Shell Ternary Electrodes for High-Performance Ionic Actuator in Soft Gripper.

Ionic actuators based on composite electrodes consisting of nanomaterials and conducting polymer typically offer the advantages of low-voltage operation and high stability, however, electrode preparation using conventional mixing suffers from issues of ineffective dispersion of nanomaterials, greatly diminishing their synergistic effects. Here, the ternary electrode system based on SWCNTs/PEDOT: PSS/ionic liquid using the two-step dispersion process is optimized, achieving a uniformly coated core-shell structure with high conductivity (≈392.4 S cm). The ions migration process is analyzed according to the core-shell model, further optimization of the ternary electrode and device structure enables the actuator to realize the peak-to-peak strain per volt reaching 1.3% V and normalized blocking force of 0.15 MPa V (≈89.2 times its own weight), with stable performance maintained over 1 million cycles. Therefore, the actuator can be utilized for the assembly of multi-clawed grippers to grasp precision components or larger objects. Multiple connected actuators fulfill a complex deformation, indicating promising applications in smart grippers, bioinspired robotics, and human-machine interaction.