Electrochemical Impedance Spectroscopy and Electromechanical Behavior of Bucky-Gel Actuators Containing Ionic Liquids

In this paper, bucky-gel electrodes containing various ionic liquid species were prepared by casting, using "bucky gel", a gelatinous room-temperature ionic liquid (IL) containing single-walled carbon nanotubes (SWCNT). Their electrochemical impedance responses were measured and analyzed. Also, the electromechanical responses of the actuators composed of two bucky-gel electrodes sandwiching an ionic liquid gel layer were studied by measuring the displacement due to an applied sinusoidal voltage at various frequencies. All impedance data were successfully simulated by the equivalent circuit model of a porous electrode based on the transmission line circuit model. By using the same parameter values of the porous electrode model, the frequency dependence of the strain generated in the bucky-gel actuators can be simulated. On the basis of the experimental and simulation results, the electromechanical responses of the bucky-gel actuator were analyzed by taking into account the electrochemical properties of the bucky-gel electrode. Accordingly, an electromechanical model for a bucky-gel actuator was obtained.