Electrochemical Performance of Al-1Zn-0.1In-0.1Sn-0.5Mg-xMn (x = 0, 0.1, 0.2, 0.3) Alloys Used as the Anode of an Al-Air Battery

In this work, Al-1Zn-0.1In-0.1Sn-0.5Mg-xMn (x = 0, 0.1, 0.2, 0.3) alloys are prepared and used as the anode of an Al-air battery (AAB). We use scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS) and optical microscopy (OM) to analyze the microstructures of the alloys. The hydrogen evolution rate, electrochemical performance (including polarization curves), electrochemical impedance spectroscopy (EIS), and battery performance of the samples are examined in the 4 M NaOH electrolyte. The experimental data display that the average grain size is significantly refined after adding manganese into the Al-1Zn-0.1In-0.1Sn-0.5Mg alloy, with a decrease in grain size from over 100 μm to about 10 μm. The improved activity of the aluminum anode in the AAB can be attributed to the introduction of manganese. The Al-1Zn-0.1In-0.1Sn-0.5Mg-0.1Mn alloy possesses the optimal overall performance with a lower self-corrosion rate (0.128 mL∙cm−2∙min−1), the highest working potential (1.630 V) and energy density (2415 mWh·g−1), a higher capacity (1481 mAh·g−1) and anodic utilization (49.75%).