Electrochemical impedance spectroscopic study of the intercalation of lithium and sodium ions into polyparaphenylene in carbonate-based electrolytes

Electrochemical impedance spectroscopy is used to investigate the electrochemical intercalation of lithium and sodium ions into polyparaphenylene under galvanostatic conditions in carbonate-based electrolyte. The evolution of the charge transfer resistance was studied at various selected potentials both during the reduction and the oxidation processes in order to control the stoichiometry of the intercalated compounds. The reversibility of the intercalation process, the effect of the cycling and the stability of the intercalated materials in the electrolyte as a function of the time were examined. A significant decrease of the charge transfer resistance occurs during the intercalation. That is related to an increase of the conductive state especially for the richest compounds Na-0.46(C6H4) and Li-0.50(C6H4). (C) 2002 Elsevier Science Ltd. All rights reserved.