Polyaniline powder of high conductivity is prepared by chemical polymerization of aniline in solutions containing 0.10 M aniline, 2 M perchloric acid and 0.15 M ammonium persulfate at 5degreesC. The powder is mixed with graphite and acetylene black for obtaining high conductivity. The chemically-synthesized polyaniline doped with perchloric acid is then used as a cathode in the construction of a bipolar rechargeable battery which employs anti-acid stainless steel as a conductive substrate for a bipolar electrode. The proposed battery contains electrochemically-synthesized zinc powder as an anode material and a solution which contains I M Zn(ClO4)(2) and 0.5 M NClO4 and 1.0 x 10(-4) M Triton-X100 at pH of 3.2 as a battery electrolyte. To prevent hydrogen reduction, I wt.% of electrochemically-synthesized optalloy is mixed with zinc powder which contains 2 wt.% MgO, 4 wt.% ZnO and I wt.% sodium carboxymethyl cellulose. To investigate the effect of separator thickness on battery efficiency, three batteries are constructed with one, two and three layers of separators. Each sub-cell from the battery has an open-circuit voltage of 1.6 V. Two bipolar batteries with open-circuit voltages of 3.2 and 6.4 V are constructed and tested successfully for 100 charge-discharge cycles. The batteries have a capacity of 110 mA h g(-1) and Coulombic efficiency of >90%. (C) 2003 Elsevier B.V. All rights reserved.