Impedance Spectroscopy Study of Fiber-Based Supercapacitors for Wearable Electronics Applications

Abstract

Recently, the interest in wearable electronics technology has been increasing to replace conventional electronics in the near future, especially for body sensors, smart glasses, or smart watches applications. Therefore, major research efforts are needed to develop flexible energy storage devices with high electrochemical and mechanical performance. Herein, we have studied the effect of fiber structure on the impedance of the fiber-based supercapacitors. The fiber-based supercapacitors were fabricated in a two-electrode configuration combining two twisted conductive threads as electrodes and a gel electrolyte between them. Five different brands of commercially available conductive threads from Jameco, JL Fiber, BCP, 6K carbon (from easy composites), and Electronics123 Fiber were tested with different twisting structures based on the number of twists per length. The impedance of the devices was tested using the electrochemical impedance spectroscopy method to study the effect of twisting on the device's performance. The results exhibit that the Jameco thread with a capacitance of 2 mF/cm and series resistance of 1.8 Ω/cm has the highest capacitance compared to the other devices, with a lower internal resistance due to the large interface area between the electrodes and the electrolyte. The current results are inspiring the research for developing flexible and low-cost fiber-based supercapacitors to develop the emerging field of wearable electronics technology.