Supercapacitors based on composite polymer electrodes

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. (C) 2000 The Electrochemical Society.