Micro-Pseudocapacitors with Electroactive Polymer Electrodes: Toward AC-Line Filtering Applications

In this study, we investigate the frequency response of micro-pseudocapacitors based on conducting polymer electrodes such as poly(3,4-ethylenedioxythiophene) (PEDOT), polypyrrole, and polyaniline. It is shown that by proper choice of polymeric material and device structure, miniaturized micro-pseudocapacitors can match the frequency response of commercial bulky electrolytic capacitors. Specifically, we show that PEDOT-based micro-pseudocapacitors exhibit phase angle of -80.5° at 120 Hz, which is comparable to commercial bulky electrolytic capacitors, but with an order of magnitude higher capacitance density (3 FV/cm(3)). The tradeoff between the areal capacitance (CA) and frequency response in the two-dimensional architecture (CA = 0.15 mF/cm(2), phase angle of -80.5° at 120 Hz) is improved by designing three-dimensional thin-film architecture (CA = 1.3 mF/cm(2), phase angle of -60° at 120 Hz). Our work demonstrates that fast frequency response can be achieved using electroactive polymer electrodes.