Characterization of MnO2 positive electrode for Fuel Cell/Battery (FCB)

Manganese dioxide was evaluated for use as the positive electrode in fuel cell-secondary battery composite systems. Electrodes were fabricated by coating nickel foam with a mixture of MnO2 and carbon black, and the charge/discharge behaviour studied in three systems: as a secondary battery positive electrode; as the positive electrode in an alkaline fuel cell; and as the positive electrode in a composite system. MnO2 exhibited redox behaviour when used as the positive electrode in a secondary battery and subjected to charge-discharge cycles. When used as the positive electrode in a fuel cell, with a H2 supply to the negative electrode and an O2 supply to the positive electrode, the current-voltage characteristics were comparable to those obtained using a nickel positive electrode. The cell was capable of producing power when the O2 supply was temporarily interrupted. 18 refs.