Basic electrochemical techniques for the characterization of pseudocapacitive materials: a case study of CPE-K

Abstract

Pseudocapacitive materials have attracted considerable academic and industrial interest because they have the potential to combine the high energy density of batteries with the high power density of capacitors. Pseudocapacitance can be characterized using cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge-discharge measurements in a three-electrode configuration, techniques that also provide valuable insight into ionic and electronic transport. In this contribution, we present a case study demonstrating the application of these fundamental electrochemical techniques to characterize CPE-K, an archetypal self-doped conjugated polyelectrolyte with pseudocapacitive characteristics. CPE-K possesses a π-conjugated backbone and pendant ionic side chains that impart water solubility. This unique molecular architecture promotes the formation of positive polarons (self-doped), which are essential for the pseudocapacitive behavior of the material.