Suppressing self-corrosion of Al-0.5Mg-0.08Sn anode via alloying trace Ce or Sm

Abstract

The high self-corrosion rate of the aluminum anode in the alkaline electrolyte will greatly lower the anode utilization efficiency, and therefore shorten the life of the aluminum-air battery. We discover that the self-corrosion rate of Al-0.5Mg-0.08Sn alloy anode in 4 M NaOH electrolyte can be reduced by more than 90% by alloying trace (≤0.10 wt%) Ce or Sm. After alloying trace Ce or Sm, the discharge voltage of the Al-air battery is stabilized, and the anode utilization efficiency and energy density increase by ∼100%. The reduction of self-corrosion rate arises from the precipitated phase transformation from the Mg2Sn phase to the Ce5Sn3 phase or the Sm4Sn3 phase and the microstructure homogenization. This work provides a novel method to suppress the self-corrosion of primary Al-air batteries while maintaining the discharge voltage.