ELECTROCHEMICAL CHARACTERISTICS OF CHEMICALLY PREPARED POLY(3-ALKYLTHIOPHENE)

Electrochemical characteristics of chemically synthesized poly(3-alkylthiophene) having various alkyl groups are investigated for use in secondary batteries as electrode active materials. Excellent characteristics, such as nearly 100% coulombic efficiency and fairly flat potential during discharge, are observed in constant-current charge-discharge tests for all of the poly(3-alkylthiophene)s. Maximum doping levels as high as 49% are obtained for poly(3-alkylthiophene), along with relatively high energy density. Coulombic efficiencies in charge-discharge tests and apparent diffusion coefficients determined by chronoamperometry increase with number of the cycle. Such “break-in” phenomena are attributed both to retention of dopant ion, even in the discharged polymers after several charge-discharge cycles, and to structural changes caused by swelling of the polymers with electrolyte molecules during the first several electrochemical cycles. © 1990, The Electrochemical Society, Inc. All rights reserved.