A new design for dry polyaniline rechargeable batteries

Polyanilline powder of high conductivity is prepared by chemical polymerization of aniline in a solution of 0.10 M aniline, 2 M perchloric acid and 0.15 M ammonium persulfate at 5 degreesC. The powder is mixed with graphite and acetylene black to obtain the required conductivity and porosity. The mixed powder is compressed into a ring shape at a pressure of 2 t cm(-2) for use as positive electrodes (cathodes) in batteries. Zinc powder is mixed with magnesium oxide, zinc oxide and sodium carboxymethyl cellulose (CMC), and then compressed into a cylindrical shape at a pressure of 7 t cm(-2) for use as negative electrodes (anodes) in batteries. The battery electrolyte comprises 2 M Zn(ClO4)(2), I M NH4ClO4, and 1.0 x 10(-4) M Triton-X100 at pH 3. A I wt.% Optalloy powder is added to the negative-electrode composite to prevent the release of hydrogen gas. The assembled battery has an open-circuit voltage (OCV) of 1.64 V, a charge storage capacity of 125.43 m Ah g(-1), and a Coulombic efficiency greater than 95% during the first 100 charge-discharge cycles. Due to the low amount of electrolyte used, the battery is considered as a dry battery. (C) 2003 Elsevier Science B.V. All rights reserved.