Aluminum/Bromate and Aluminum/Iodate Mechanically Rechargeable Batteries

The ever-increasing characteristics of microcomputers, sensors, actuators, and communication systems require more powerful and more compact autonomous power sources. Al/bromate and Al/iodate flow batteries are proposed as new power supply units for use in oxygen-deficient environments. The batteries employ a mechanically rechargeable aluminum anode flooded with aqueous salt electrolytes or seawater, a cation-exchange membrane, and a carbonaceous porous cathode, where acidified alkali metal bromate, or iodate, is reduced in a six-electron process. The theoretical energy density of an Al/bromate flow cell per reactants is 0.65 kWh kg(-1). Seawater is assumed as an electrolyte for the anode compartment. Using a H-2/iodate flow cell, it is shown that iodate-iodine-iodide electrochemical transformations can be realized in both directions in acidic media at carbonaceous electrodes. At 30 degrees C, the area-specific power of the single cells of the Al/bromate and Al/iodate flow batteries reaches 0.26 W cm(-2) and 0.075 W cm(-2), respectively.