The effects of mechanical alloying on the self-discharge and corrosion behavior in Zn-air batteries

[Display omitted] •Zn–Bi alloys were, for the first time, prepared using a mechanical process for Zn-air batteries.•Mechanical milling time and Bi ratio were optimized to enhance the discharge retention rate.•99.50% of discharge retention rate was achieved with a 6h milled anode containing 2wt% of Bi.•H2 gas evolution and corrosion reaction were effectively suppressed by attempted Zn–Bi alloys. The corrosion behavior of Zn anodes is a major issue that must be carefully considered in Zn-air batteries. In this work, mechanically alloyed Zn–Bi specimens with different compositions are fabricated at various milling times in order to enhance the electrochemical performance of the Zn-air batteries. The presence of Bi, which could be detected with bright contrast by backscattered FE-SEM, does not change the crystal structure of Zn. While the pure Zn exhibits 74.40% of a discharge capacity retention, all the Zn–Bi alloy materials deliver more than 90% of a discharge capacity retention. Especially, the anode containing 2wt% of Bi with a 6h milled material (B3H6Bi2) exhibits the highest corrosion inhibition efficiency (91.501%) and lowest corrosion current density (0.326mAcm−2). In particular, 99.50% of a discharge capacity retention is achieved with B3H6Bi2. In terms of self-discharge behavior, the mechanical alloyed Zn–Bi materials are suggested as promising anode materials for use in Zn-air batteries.