Improving the Corrosion Resistance of Al anode and Specific Capacity in Al-air Batteries Using Mixed Electrolyte Solutions

Abstract

This research aimed to investigate the corrosion improvement in Al-air batteries and their specific capacity, at various mixed ratios of sodium chloride and sodium hydroxide solutions 100:1, 99:1, 98:2, 90:10, 80:20, 70:30, and 0:100. The battery was discharged at different discharge current densities of 1, 5, 10, and 15 mA·cm-2. The self-corrosion of Al anodes and their electrochemical behavior was tested in the mixed electrolyte solutions at room temperature. Moreover, the chemical characterization of the electrode surface was analyzed using the EDS and XPS technique showing that mixed electrolyte solutions provide complex film on the aluminum surface, consisting of various atoms of Al, O, C, Na, and Cl which can reduce the self-corrosion of the aluminum anodes, and providing a higher energy capacity. Mixed electrolyte solutions with a sodium chloride to sodium hydroxide ratio of 80:20 by volume at a discharge current of 15 mA·cm-2 causes a maximum specific capacity of 1,508 mA·h·g-1. The mixed electrolyte solutions can increase the specific capacities of Al-air batteries by 1.4 and 25.6 times more than that of sodium chloride solution and sodium hydroxide solution alone, respectively.