We have fabricated an all‐polymer battery utilizing the redox properties of electrically conducting polymers for the anode and cathode in conjunction with an ionic conducting polymer gel electrolyte. The anode and cathode consist of pyrrole electropolymerized onto a graphite fiber substrate resulting in a high‐surface‐area, composite electrode. A polymer gel electrolyte, based on polyacrylonitrile, was solution cast onto the electrodes to form an all‐polymer cell. This system exhibits a specific charge capacity of 22 mAh g−1 based on the electroactive mass of the cathode and discharging the system to 0.4 V. These cells show no loss of capacity when cycled to 100 cycles.

The influence of Bi-or Ba-containing compounds on the rechargeability of ␥-MnO 2 in alkaline electrolytes has been investigated with AA cells containing cylindrical cathodes and flooded cells containing thin-film type cathodes. In addition to the electrochemical evaluation of the cells, the discharged cathodes were analyzed by X-ray diffraction after washing and drying. The incorporation of bismuth or barium into the cathodes was found to improve the cell cyclability, which is partly due to the suppression of electrochemically inactive phases such as birnessite (␦-MnO 2 ) and hausmannite (Mn 3 O 4 ). A series of chemical oxidation reactions of Mn͑OH͒ 2 with H 2 O 2 in KOH medium and nonredox reactions of Mn͑III͒ acetate with KOH followed by an analysis of the solid and filtrate indicate that the Mn 3ϩ ions, which were in equilibrium with the solid phases containing Mn͑III͒, disproportionated into Mn͑II͒ compounds and Mn͑IV͒ oxides. Reaction mechanisms involving Mn͑III͒ compounds in KOH solution and the role of bismuth or barium on those reactions are discussed.

No abstract

The electronic conductivity and redox behavior of conjugated polymers make them suitable for charge storage applications. We present preliminary results for an all polymer system consisting of a p-doped polypyrrole cathode and pseudo n-doped polypyrrole/polystyrenesulfonate anode. Using a thin film construction technique, electrodes were assembled into cells using a polymer gel electrolyte based on polyacrylonitrile, which has a high room temperature conductivity. Charge capacities of 13 mAh g−1 based on the mass of the electroactive polymer in the cathode have been obtained for over 100 cycles.

Novel composite electrode structures have been fabricated by single‐step electropolymerization of polypyrrole onto a porous graphite fiber matrix. The graphite substrate provides a lightweight structure with high surface area. The available charge capacity of the composite electrodes was proportional to the electropolymerization time and the mass of electroactive polymer with reversible charge capacities in excess of 4.0Ccm−2 and a specific capacity of 90 mAh g−1 , independent of polymer mass. The rate of charge extraction was dependent on the polymer mass and the morphology of the polymer electrode. In test cells using a polypyrrole/graphite fiber anode and a polypyrrole‐polystyrene sulfonate/graphite fiber cathode, we have demonstrated a capacity of more than 40 mAh g−1 based on the active mass of the undoped polymer on discharging the cell to 0.1 V over a 10 kΩ load. More than 70% of the available charge was extracted from the cell over 50 cycles with no degradation of cell performance.