The influence of Ga, Sn, or Bi addition on the electrochemical behavior and discharge performance of Al–Zn–In anodes for Al-air batteries

In this work, experimental methods, such as electrochemical measurements, hydrogen collection technique, battery performance tests, and microstructure analysis, are used to investigate the electrochemical properties and discharge behaviors of Al–4.5Zn–0.05In and Al–4.5Zn–0.05In–0.05Ga/Sn/Bi anodes in 4 M NaOH solutions. Results suggest that the discharge performance of Al–Zn–In anodes can be further enhanced by adding Ga, Sn, or Bi elements. These elements show a dissolution-deposition behavior on the anode surface, which reduces the resistance of the passive film and increases the activity of active sites on the electrode surface. Also, adding Sn or Bi works better than adding Ga. Because Ga element is likely to cause severe local corrosion at the grain boundaries. Furthermore, the peak energy densities of Al–4.5Zn–0.05In–0.05Sn and Al–4.5Zn–0.05In–0.05Bi anodes at 40 mA cm −2 are approximately 3628.64 Wh kg −1 and 3456.12 Wh kg −1 , respectively, which are 29.6% and 23.5% higher than that of Al–4.5Zn–0.05In anodes. Graphical abstract