Electrochemical properties of aluminum anodes in gel electrolyte-based aluminum-air batteries

Various concentrations of potassium hydroxide (KOH) solution electrolytes were gelled with a hydroponics gelling agent and used in aluminum-air (Al-air) cells. An aluminum plate and a single air-cathode were used as the anode and cathode, respectively. The cells were discharged at a constant current density of 0.08, 0.80 and 1.60 mA/cm2. The 0.6 M KOH concentration gave the highest capacity and power density of 105.0 mA h/g and 5.5 mW/cm2, respectively. The capacity of the fabricated cell decreased when the KOH concentration went beyond 0.6 M. The corrosion of Al to Al(OH)3 as shown by the structural and surface morphology observations was the main factor for the failure of the cells.