ELECTROCHEMICAL STUDIES OF POLYANILINE AND ITS APPLICATION

The weight change of polyaniline (PAn) positive electrode in LiClO//4/propylene carbonate (PC) electrolyte during charge/discharge process was observed in situ by an electrogravimetric technique. The weight of PAn in the electrolyte increased linearly upon charge and decreased linearly upon discharge. The results suggests that the charge/discharge reaction of PAn in the non-aqueous electrolyte proceeds with doping/undoping of anion species. The anion species is supposed to be ClO//4** minus anion solvated with 3-4 propylene carbonate molecules. The solubility of the doped anion to the solvent affects the rechargeability of PAn. Therefore, the use of HClO//4 or HBF//4 aqueous electrolyte is preferable for the synthesis of PAn. PAn in the non-aqueous medium is very stable even in the higher oxidized state and shows the highest discharge capacity (150 Ah/kg) of the other conducting polymers.