Micro-alloyed aluminium alloys as anodes for aluminium-air batteries with a neutral electrolyte

Abstract

Aluminium (Al)-air batteries possess a low cost, high theoretical capacity, efficiency, and good recyclability. However, aluminium metal, as the anode material, suffers from low anodic efficiency and limited battery storage life. In this study, three extruded micro-alloyed Al alloys (Al-0.1Fe-0.3Si, Al-0.2Fe-0.2Si, and Al-0.2Fe-0.8Si) were investigated as anode materials for Al-air batteries in a neutral electrolyte. These three alloy anodes were also discharged in an alkaline electrolyte for comparison purposes. The results indicate that the micro-alloying elements Fe and Si accelerate corrosion in a neutral electrolyte. The composition of Fe and Si micro-alloying adversely affects the anodic performance of Al-air batteries but benefits the electrochemical activity of the aluminium substrate. In alkaline electrolytes, aluminium alloy anodes suffer severe self-corrosion and exhibit low anodic efficiency. Additionally, Al-0.1Fe-0.3Si and Al-0.2Fe-0.2Si alloys exhibit better battery performance than Al-0.2Fe-0.8Si at the current densities <10 mA·cm−2 in a neutral electrolyte.