Based on the cyclic voltammograms and impedance spectra of poly(aniline-co-m-aminophenol) in the electrolyte solution containing ZnCl2 and NH4Cl2 a solution consisting of 2.0 M ZnCl2 and 3.0 M NH4Cl with pH 4.70 was employed as an electrolyte solution of a Zn-poly(aniline-co-m-aminophenol) battery. The battery was charged and discharged between 0.75 and 1.45 V at different current densities. The average charge voltage is about 1.15 V and the average discharge voltage is about 1.05 V, slightly depending on the charge-discharge current density. The capacity and energy densities of poly(aniline-co-m-aminophenol) are 137.5 A h kg(-1) and 152.5 W h kg(-1) for discharge process, respectively, which are much better than those of polyaniline at the same solution. After the test of the charge-discharge at different current densities, the battery was successively charged and discharged for 120 cycles. At one-hundred and twentieth cycle, the coulombic efficiency is 100% and the energy density of poly(aniline-co-m-aminophenol) only decreases by 9.2%, compared with the first cycle of the successive charge-discharge processes. (c) 2006 Elsevier B.V. All rights reserved.