Electrochemical synthesis of electronic and ionic conductive polymer composite polyaniline/PEO network

A bilayer composite of conducting polyaniline was prepared by electrochemical polymerization of anilinium salt (dissolved in appropriate solvent like DMF, methanol, or water) in poly(ethylene oxide) PEO network. When washed, dried and doped with LiClO4, the bilayer showed electro-chemical activity corresponding to doping and undoping reactions in the solid state. The bilayer was characterized by FT-IR (reflection), UV spectroscopy and microscopic examination while the electrochemical activity in the solid state was examined by cyclic voltammetry. Cyclic voltammetry of the composite conductive polymer and polymer electrolyte in the solid state against Pt produced oxidation peaks at 0.26 and 0.78 V. Against Li, a broad oxidation peak appeared between 0.5 and 4.5; doping efficiency in the Li cell reached 95% between 2-4 V at a scan rate of 100 mV/s. The color of the conducting polymer as anode changed from transparent yellow to green and then to blue during the doping process. Cole-cole plots of the composite obtained by AC impedance measurements showed an arc at high frequency region (>2.82 MHx) due to polymer electrolyte impedance. Another arc due to impedance of the doping reaction, at lower frequency (>20 Hz) followed as doping of the conductive polymer preceeded; the arc is then joined by a Warburg line, which characterizes diffusion controlled kinetics at the low frequency region (<20 Hz). (auth.). 17 refs.; 14 figs. 2 tabs