Electroactive Polyaniline Film Deposited from Nonaqueous Media: III . Effect of Mixed Organic Solvent on Polyaniline Deposition and Its Battery Performance

Abstract

Electroactive polyaniline (PAn) films were deposited from PC (propylene carbonate)‐EC (ethylene carbonate) and PC‐DME (1,2‐dimethoxyethane) mixed polymerization solutions containing aniline, CF3COOH , and LiClO4 . Higher dielectric constant solvents are necessary to deposit the PAn film where protons, dissociated from the acid, initiate the polymerization of aniline. Various PAn films deposited in the PC, the PC‐EC (50 mole percent), and the PC‐DME (50 volume percent) solutions were used for the cathode materials of the rechargeable lithium batteries. Charge capacity and discharge ability of the Li/PAn batteries in the PC‐LiClO4 electrolyte solution are almost the same, regardless of the polymerization solvents, such as PC≈PC‐EC≥PC‐DME and PC‐EC≥PC‐DME≈PC . The mixed solvent electrolyte solution effect on the Li/PAn (polymerized in the PC solution) batteries becomes much larger such as PC‐DME>PC‐EC>PC . Moreover, the electrochemical kinetic factors of the PAn films deposited in the various mixed polymerization solutions and also in the different electrolytes were experimentally determined by measuring the ac impedance. The results of the ac impedance analysis of each PAn film correlate well with the battery performances of Li/PAn cells.

Electrochemical Impedance Spectroscopy (EIS) for Polymer Characterization

“…where the element z 1 is the impedance per unit length of the transport channel in the polymer phase, z 2 is the impedance per unit length of the transport channel in the pores, L is the thickness of the film, and f = [z 3 /(z 1 + z 2 )] 1/2 where z 3 represents the specific impedance at the inner interface, which corresponds to charge transfer and charging processes [142]. Equation (3.22) can be transformed in the following form:…”

The influence of the PANI structure on the conductive mechanism and on the electrical equivalent circuit analysis

“…At the same time the Bode spectra indicate large negative phase shift (<À90°) in the low frequency region, which is typical capacitance behavior [3][4][5][6]. However, if the detailed investigation of the impedance response of the thin PANI layers is required, the electrical equivalent circuit (EEC) can be used [6,41,42]. The application of EEC results in parameters that are used for further analysis.…”

Electrosynthesis and characterisation of poly(N-methylaniline) in organic solvents

“…One possibility to avoid the presence of water in the polymer matrix is to perform the electropolymerisation in organic solvents. Osaka et al [20][21][22][23] have studied the electropolymerisation of PANI in propylene carbonate (PC). They performed the electropolymerisation of PANI in a PC solution containing 0.5 M aniline, 0.5 M trifluoroacetic acid (CF 3 COOH) and 0.5 M LiClO 4 as the electrolyte salt [21].…”