Rechargeable Alkaline Zinc Battery Chemistry FAQ

Rechargeable Alkaline Manganese Cells

Anode: Zinc

Cathode:Manganese Dioxide

Electrolyte: Potassium Hydroxide Solution

Applications: Consumer devices

Yes, this is the familiar alkaline battery, but specially designed to be rechargeable, and with a hot new acronym—RAM (haven't I seen that acronym somewhere before?). In the charging process, direct-current electrical power is used to reform the active chemicals of the battery system to their high-energy charge state. In the case of the RAM battery, this involves oxidation of manganese oxyhydroxide (MnOOH) in the discharged positive electrode to manganese dioxide (MnO2), and of zinc oxide (ZnO) in the negative electrode to metallic zinc.

Care must be taken not to overcharge to prevent electrolysis of the KOH solution electrolyte, or to charge at voltages higher than 1.65 V (depending on temperature) to avoid the formation of higher oxides of manganese.