Abstract
The cyclability performance of several composite polymer electrodes based on poly(thiophene) (pTh), poly(3‐methylthiophene) (pMeT), and poly[3‐(4‐fluorophenyl)thiophene] (pFPT), carbon, and a binder is reported. These composites were tested for use as positive and negative electrodes in supercapacitors for electric vehicle (EV) applications. The pTh composites were characterized for use as a positive electrode, the pFPT as negative, and the pMeT as both positive and negative electrode. Different types of symmetric and unsymmetric composite polymer supercapacitors were developed and characterized in propylene carbonate‐tetraethylammonium tetrafluroborate electrolyte by several thousand deep, galvanostatic charge‐discharge cycles at selected currents to restrict the discharge time to EV‐suitable values (<100 s). The best device as to specific energy and power was the unsymmetric pMeT/pTh composite supercapacitor. © 2000 The Electrochemical Society. All rights reserved.