Electrochemical and physical characterization of lithium ionic salt doped polyaniline as a polymer electrode of lithium secondary battery

Polyaniline films doped with lithium ionic salts such as LiPF6 and LiBF4 were prepared by using the electrolyte solution mixture of ethylene carbonate and dimethyl carbonate. The doping level of the polyaniline films was confirmed by X-ray photoelectron spectroscopy and de conductivity experiments. A doping mechanism of lithium ion through the interaction with a nitrogen at imine site is proposed. Electrochemical cells of Li//polyaniline-LiPF6 or Li//polyaniline-LiBF4 were assembled to investigate electrical capacity and its trends over the repeated charge/discharge cycles. The capacity of Li//polyaniline cell was increased and then saturated over 15 cycles. However, it did not reach the half of theoretical capacity of polyaniline material. The mechanism of electrochemical reaction during charge/discharge process of Li//polyaniline cell is presented. (C) 2000 Elsevier Science S.A. All rights reserved.