Development of Aluminum-Air Battery Using an Ionic Liquid Electrolyte Solution

Prototype Al-air primary battery was constructed to avoid self-discharging due to chemical dissolution of Al in a concentrated alkaline electrolyte during non-operation condition. The battery was composed of two compartments; one of which contained hydrophobic ionic liquid（EMIIM-TFSI）and KOH pellets, and the other contained alkaline KOH aqueous solution and air electrode. Two compartments were separated with an anion exchange membrane. Although EMIIM-TFSI had hydrophobic property, it could contain a little amount of water to enable Al dissolution. Results of current-voltage curve measured in various conditions indicated that the internal resistance of the battery was rather high to limit the battery performance. Impedance analysis using proper arrangement of a pseudo-reference electrode of Ag wire in the battery enabled to estimate resistance of each component of the battery to clarify the bottleneck of this system.