Influence of microstructure evolution on the discharge properties of the Al–Mg–Sn–Ga–In anode for Al–air batteries

Abstract

In the present work, after annealing at 150 °C–450 °C for 1 h, the influence of precipitate, grain structure and texture evolution on the discharge properties of the Al–0.25Mg–0.2Sn–0.04Ga–0.04In anode for Al–air batteries was investigated in detail. When the annealing temperature is not higher than 250 °C, the alloy shows high electrochemical activity attributed to the fine fibrous structure with high-density of dislocations and high corrosion resistance due to the high fraction of low angle grain boundaries, brass and Goss textures. The 150 °C annealed alloy exhibits high specific capacity, energy density and anode utilization of 2722.3 mA h g⁻¹, 3020.0 mW h g⁻¹ and 91.35%, respectively at 60 mA cm⁻². The alloy annealed at 350 °C displays the lowest discharge performance as a result of the growth of grains, high fraction of high angle grain boundaries with Sn-rich phases and the reduction of brass and Goss textures. When the annealing temperature further increases to 450 °C, both the corrosion resistance and discharge voltage at a high current density of the alloy improve on account of the dissolution of Sn-rich phases. This is responsible for the highest discharge capacity of 2777.8 mA h g⁻¹ and anode efficiency of 93.21% of the alloy at 60 mA cm⁻².