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

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 LiC10₄. 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–LiC10⁴ 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.