Regulating discharge performance of Mg anode in primary Mg-air battery by complexing agents

•Strong complexing agents decrease the discharge potential of Mg anode.•Weak Mg2+ complexing agents improve the utilization efficiency and specific capacity.•The utilization efficiency reaches 72.3% after addition of 0.1 M sodium salicylate.•Discharge performance depends on the weight loss caused by self-corrosion and chunk effect. Deposition of discharge products on the surface of magnesium (Mg) anode and high self-corrosion rate are the main obstacles that limit the application of Mg-air batteries. Tailoring electrolyte additives in Mg-air batteries has been proved to be an efficient way to improve the discharge performance of Mg-air batteries. In this work, the influence of several complexing agents on the discharge potential and utilization efficiency of Mg anode is studied by means of half-cell discharge test. The results show that strong Mg2+ complexing agents can significantly lower the discharge potential of Mg anode. Mg2+complexing agents with low stability constant can improve the utilization efficiency and specific capacity of the anode compared to complexing agents with strong complexation ability. The utilization efficiency of anode reaches 72.3% at 10 mA cm−2 after addition of 0.1 mol/L sodium salicylate. Moreover, salicylate deposits on the anode surface after discharge, which has a negative influence on the discharge potential of Mg anode.