Analysis of impedance spectroscopy of aqueous supercapacitors by evolutionary programming: Finding DFRT from complex capacitance

In this work, EIS data of aqueous-electrolyte supercapacitors were analyzed by transforming the data to complex capacitance representation. A distribution function of relaxation times (DFRT) model was obtained, comprised of two peaks, each correlated with a different physical process (diffusion and EDLC formation). Two cell configurations were examined and the differences regarding capacitance distribution and diffusion rates are presented.