Influence of adding Mg, Sn and Ga on the discharge property of the Al-Sb anode for Al-air batteries

Abstract

Al-air batteries have become one of the most potential candidates in industrial application. In this study, the influence of Mg, Sn and Ga on the electrochemical behavior and anode property of the Al-Sb alloy is investigated in detail. The single addition of Mg increases the discharge activity and suppresses the hydrogen evolution corrosion, improving the anode property of the Al-Sb alloy. The Al-0.3Mg-0.05Sb alloy presents high specific capacity of 2881.8 mAh∙g−1, outstanding anode utilization of 96.71 % and energy density of 2356.5 mWh∙g−1 at 80 mA∙cm−2. This is because Sb-rich phases enhance the uniform dissolution of the grain boundary and improve the corrosion resistance. Simultaneously adding Mg and Sn improves the energy density of the Al-Sb alloy at high current density. The Al-Sb alloy presents the highest energy density at 80 mA∙cm−2 by simultaneous addition of Mg, Sn and Ga. But the aggravating hydrogen evolution corrosion and serious intergranular corrosion lead to obvious decrease of the specific capacity and anode utilization of the Al-Sb alloy, which is attributed to excessive precipitates and segregation of Ga along the grain boundary.