Polyaniline: characterization as a cathode active material in rechargeable batteries in aqueous electrolytes

Abstract

An analytically pure form of chemically synthesized polyaniline having the emeraldine oxidation state has been used as a cathode active material together with a Zn anode in the fabrication of rechargeable cells in 1.0 M aqueous ZnCl₂ electrolyte (pH∼4). The experimental capacity and energy density based only on the weight of polymer employed in constructing the cell are 151.5 Ah kg⁻¹ and 159.1 Wh kg⁻¹ respectively at a constant discharge current of 0.75 mA cm⁻² (average discharge voltage 1.05V). The cell reactions in the charge and discharge processes have been determined. The modified capacity and energy density, when taking into account the calculated weights of Zn and HCl involved in the discharge reactions, are 109.3 Ah kg⁻¹ and 114.8 Wh kg⁻¹ respectively. The cell shows excellent recyclability and coulombic efficiency.