Development of the electrochemical performance of zinc via alloying with indium as anode for alkaline batteries application

Zinc is one of the predominantly utilized metals in alkaline batteries. The addition of a trace amount of indium as an alloying element to zinc retards the rate of corrosion and promotes the sacrificial protection of zinc. The corrosion behavior of Zn and Zn–In alloy at various In content (0.5% and 1%, In/Zn mass fraction) in 6 M KOH solution was electrochemically studied. Tafel plots, electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and charge-discharge methods were all employed. The morphology, chemical composition, and phases of the corrosion layers formed on the surfaces of Zn and Zn–In alloys were thoroughly investigated utilizing scanning electron microscopy (SEM) equipped with an X-ray of dispersed energy (EADX) and X-ray diffraction (XRD), respectively. The polarization results revealed that the corrosion protection efficiency of the Zn–1%In alloy has the highest value of 97.3% at 45 °C. The steady-state of open circuit potential (Ecorr.) for the investigated alloys is shifted to a more negative value compared to that of zinc. This indicates that the alloying of zinc with indium has a positive effect on charge efficiency, suppression of hydrogen evolution reaction, and the capacitance. Moreover, the discharge time increases with the increase of the indium percentage in the bimetallic solid solution of Zn–In. The synthesized alloy is considered a promising material for long life alkaline batteries.