A series of thiophene-based conducting polymers has been synthesized. The properties of these polymers were characterized using electrochemical techniques. The polymerization potentials of the monomers were found to be related to the corresponding Hammett a values. The maximum n-doping levels of the polymers were also found to be correlated with the Hammett sigma values. No correlation was found with the maximum p-doping levels of the polymers. The doping densities were found to decrease on repeated cycling and were correlated with irreversible morphological changes in the films. Test cells were fabricated using conducting polymer films for both anode and cathode. These cells exhibited discharge voltages of about 2.5 V and capacities of 9.5 to 11.5 mA h g(-1).