Development of low-carbon energy storage material: Electrochemical behavior and discharge properties of iron-bearing Al-Li-based alloys as Al-air battery anodes

With inevitable introduction of Fe in aluminum processing, a method for achieving high-value utilization of iron-bearing aluminum-based alloys is essential. Aluminum-air batteries are among the most promising power sources and have attracted the attention of researchers. In this study, the electrochemical behavior and discharge properties of Al-0.5Fe and Al-0.5Mn-0.5Fe-0.1Sn-xLi (x = 0, 1, 2, and 3 wt %) alloys as Al-air battery anodes are investigated in 4 M NaOH. Using x-ray diffraction (XRD) and scanning electron microscopy (SEM), the constituents and distributions of the main phases are discussed. Alloying improves electrochemical behavior and discharge properties of Al-0.5Fe. The static and dynamic electrochemical experiments indicate that Al-0.5Mn-0.5Fe-0.1Sn-2Li exhibits the best corrosion resistance. The discharge performances of the five alloys show that the average voltages decrease with increasing current density and Li content. Based on the electro-chemical and discharge results, Al-0.5Mn-0.5Fe-0.1Sn-2Li is an excellent candidate for use in Al-air battery anodes, reaching a peak anodic efficiency of 77.86% at a relatively high current density of 80 mA cm-2, with a power density and specific energy of 83.60 mW cm-2 and 1618.06 mW h g-1, respectively. The optimal discharge performance is attributed to dispersed AlLi particles and the fragmentation effect of AlLi on the long strip-like Al6Mn(Fe) phase.