Experimental investigation and controllability study of electrochemical actuators based on Si/CNTs composite material

Electrochemical actuators can convert electrical energy into mechanical energy directly and have been applied widely. With a large volume expansion in the electrochemical reaction, silicon material demonstrates enormous potential in the manufacture of the electrochemical actuators. Here, we propose a new electrochemical actuator based on Si/CNTs composite electrode. A mathematical model is developed to analyze the relationship among material parameters, structural changes, and bending deformation. The curvature changes of the cantilever beam are captured by a CCD camera during electrochemical cycling. Combining the model and bending curvatures, the modulus and swell strain are extracted and detailed analyzed. Here, the elastic modulus of the composite electrode softens and decreases from 9.59 GPa to 4.78 GPa, while the swell strain increases from 0.12% to 2.97% when arriving 6% normalized concentration of lithium. These results show that the composite material possesses excellent bending resistance and deformation ability. Also, the curvature changes under different thickness ratios are predicted successfully, the evolution of stress in the working electrode is simulated, and the loading experiment of the actuator is carried out. This work provides a new way to realize the controllability of the electrochemical actuators.