The role of micro-naoscale AlSb precipitates in improving the discharge performance of Al-Sb alloy anodes for Al-air batteries

The role of micro-nano AISb precipitates in the electrochemical behaviors and discharge performance of Al-Sb alloys is discussed in detail. The micro-nanoscale AlSb precipitates significantly improve the discharge activity and inhibit the self-corrosion rate of Al-Sb anodes, resulting in higher cell voltage and anodic efficiency than pure Al. A continuous stream of micro-nanoscale AlSb precipitates can provide a good inhibiting effect on the localized consumption of grain boundary at large current density. Furthermore, the oxidation of AISb precipitates provides a Sb-containing film, which covers the cathodic site and greatly decreases growing rate of passive film on the anode surface. The Al-0.06Sb alloy exhibits the peak anodic efficiency as high as 98.2% at 40 mA.cm(-2). Meanwhile, it can still output a high energy density of 3781 Wh.kg(-1) at 20 mA.cm(-2). However, excess amount of micro-nano AlSb precipitates strongly aggravates the localized dissolution of anodes, which is detrimental to the anode performance. The microstructure refinement is also beneficial for the enhanced anode performance.