Fe(VI) catalyzed manganese redox chemistry: Permanganate and super-iron alkaline batteries

In principle, alkali permanganates represent a substantial cathodic charge source for electrochemical storage, but high rate charge transfer has been inefficient. This study presents a novel Fe(VI) species (super-iron) and manganese redox chemistry synergism. Also presented is the high discharge energies from cathodes which utilize this phenomenon in a conventional cylindrical battery configuration. Batteries formed with a cathode combining BaFeO4 and KMnO4, and using a conventional zinc alkaline anode in an AAA cylindrical cell configuration, exhibit an unusually high discharge capacity of 2.2 Wh. The discharge efficiency of solid alkaline permanganate or manganate cathodes is probed, and improved charge transfer of Mn(VII) redox chemistry in the presence of Fe(VI) is demonstrated. In a reciprocal manner, enhancement of Fe(VI) charge transfer are demonstrated upon inclusion of manganese salts, and also that added cesium further improves the combined Fe(V)/Mn(VII) cathode.