Effect of Pulse Current Treatment on Anode Corrosion and Discharge of AZ91 Magnesium Alloy

Aqueous Mg-air batteries are currently facing issues with self-corrosion and hydrogen evolution at magnesium alloy anodes. Reducing self-corrosion and improving the discharge performance of magnesium alloys have become hot research topics in this area. This paper examines the electrochemical and discharge capabilities of AZ91 magnesium alloy anodes post-electrical pulse treatment, employing microscopic analysis, electrochemical assessments, and trials with magnesium-air batteries. The thermal and non-thermal effects generated by electric pulse treatment can promote the dissolution of the β-Mg₁₇Al₁₂ phase. The extent of dissolution of the β-Mg₁₇Al₁₂ phase is correlated with the peak current density of the electric pulse. The A-12 alloy exhibits the highest discharge activity, attributed to the specific distribution of the second-phase structure formed post-electric pulse treatment. Compared to the as-cast AZ91 magnesium alloy, the corrosion resistance of AZ91 magnesium alloy is significantly enhanced after the electric pulse treatment. It has a higher discharge activity at high current densities. In addition, compared with the other four alloys, the AZ91 magnesium alloy treated with a pulse current of 3  \({\text{A}}\;{\text{mm}}^{ - 2}\) $\text{A}{\text{mm}}^{-2}$ has more excellent discharge performance, the anode utilization rate (61.33%) and specific capacity (1333.33  \({\text{mAh}}\;{\text{g}}^{ - 1}\) $\text{mAh}{\text{g}}^{-1}$ ) reached their peak values during discharge at a current density of 15  \({\text{mA}}\;{\text{cm}}^{ - 2}\) $\text{mA}{\text{cm}}^{-2}$ , which was about 25% higher than that of the as-cast AZ91 magnesium alloy, and the discharge curve was more stable.