Tailoring the electrochemical behavior and discharge performance of Mg–Al–Ca–Mn anodes for Mg-air batteries by different extrusion ratios

Abstract

This work investigates the electrochemical behavior and discharge performance of Mg–3Al-0.4Ca-0.7Mn alloys with three extrusion ratios (ER) of 10, 16 and 25 as anodes for Mg-air batteries. The results show that the ER16 sample has the lowest corrosion current density and the highest corrosion resistance. The corrosion performance of the ER25 sample is slightly reduced due to the excessive discontinuous second phase leading to elevated self-corrosion rate. The alloy exhibits higher discharge voltage and stable discharge process with increasing extrusion ratio. Increasing the extrusion ratio has a homogeneous microstructure, the increase in the area fraction of non-basal oriented grains is conducive to the homogeneous dissolution of the anode and the inhibition of the “chunk effect”. The ER25 sample showed the highest anode efficiency, specific capacity and energy density of 55.73 %, 1306.67 mA h g-1 and 1635.947 mW h g−1 at 20 mA cm−2, respectively.

Keywords

• Mg-air batteries
• Second phase
• Electrochemical behaviors
• Discharge properties