Characterization of poly(N-methylaniline) as a cathode active material in aqueous rechargeable batteries

Electrochemically deposited poly(N-methylaniline) (PNMA) is evaluated as a cathode active material together with a Zn anode in the fabrication of rechargeable cells in 1 M ZnSO4 electrolyte at pH similar to5. The cell shows an open-circuit voltage (OCV) of 1.35 V and a specific capacity of 25.8 Ah kg(-1). In a second set of experiments, the anion-exchanging PNMA is converted to a cation-exchanging electrode by sulfonation and evaluated in cells. Such an approach enhances the specific capacity of the cell by a factor of 4. The coulombic efficiency of the cell is also increased considerably. A few related experiments are performed on the parent polymer, polyaniline, to facilitate direct comparison of the results. (C) 2002 Elsevier Science B.V. All fights reserved.