2023 AIChE Annual Meeting
Equivalent Circuit Model Analysis for Electrochemical Characterizations of Textile-Based Supercapacitors
Textile-based supercapacitors (TSCs) hold untold potential benefits as lightweight, wearable, safe, and convenient source of energy for commercial and personal electronics. TSCs are fabricated with highly conductive yarns knitted together into electrodes. Herein, Ti3C2Tx MXene, a two-dimensional transition-metal carbide with a conductivity as high as 10 kS/cm, is used to fabricate conductive yarns. In this study, cotton and wool yarns are coated with MXene flakes to build TSCs. Subsequently, electrochemical characterizations including cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were conducted. Equivalent circuit models (ECMs) were constructed based on the physics of the device and fitted to the EIS measured data to determine the theoretical resistance and capacitance. EIS analysis reveals that the TSCs stray from an ideal Randles circuit model and act as a constant phase element (CPE), resembling an imperfect double-layer capacitor. The selected model adds a Warburg impedance in parallel to adjust for further mass diffusion resistance. These models will be used in future fabrication and analysis of improved TSCs with lower resistance and more pseudocapacitive behavior. From electrochemical characterization, cotton TSCs achieved an areal capacitance of 823.9 mF/cm2 while wool TSCs achieved 284 mF/cm2 at a scan rate of 5 mV/s.