Electrochemical behaviour and discharge characteristics of an Al–Zn–In–Sn anode for Al-air batteries in an alkaline electrolyte

The electrochemical behaviour and discharge characteristics of Al-4.5Zn-0.05In (wt.%), Al-4.5Zn-0.05Sn (wt.%) and Al-4.5Zn-0.05In-0.05Sn (wt.%) anodes for Al-air batteries in 4 M NaOH solutions are investigated through electrochemical methods, full-cell tests, and microstructure observations. Adding Sn to the Al-4.5Zn-0.05In (wt.%) anode improves its discharge performance. Sn ions, like In ions, can be repeatedly adsorbed and desorbed onto the anode surface, resulting in the attenuation of the passivation layer. The Al-4.5Zn-0.05In-0.05Sn (wt.%) anode exhibits better discharge characteristics than the Al-4.5Zn-0.05In (wt.%) and Al-4.5Zn-0.05Sn (wt.%) anodes, especially at large current densities. Furthermore, the peak energy density of the Al-4.5Zn-0.05In-0.05Sn (wt.%) anode can reach approximately 3628.64 Wh kg−1, which is 11.80% and 14.21% higher than that of Al-4.5Zn-0.05In (wt.%) and Al-4.5Zn-0.05Sn (wt.%) anodes, respectively. •Sn improves the discharge properties of Al–Zn–In anode in alkaline electrolyte.•In ions or Sn ions reduce the resistance of the ZnO passivation film.•Peak energy density of the anode reaches about 3628.64 Wh·kg−1 (at 40 mA cm−2).