Engineering

Metallurgy

Materials science

Layer (electronics)

Indium

Alkaline battery

Inorganic chemistry

Chemical engineering

Zinc

Dissolution

Physical chemistry

Nanotechnology

Composite material

Corrosion

Chemistry

Scanning electron microscope

Electrode

Electrolyte

Bimetal

Passivation

Journal of Solid State Electrochemistry

Zinc metal is an important element that can be used for long-life alkaline batteries. In this work, it is found that the addition of minor amounts of indium can slow down the corrosion rate and maintain the sacrificial protection of Zn in the alkaline media of batteries. The performance of anodic dissolution and passivation for Zn and Zn-In bimetal in the alkaline solution of 6 M KOH was investigated via potentiodynamic and potentiostatic methods. Furthermore, the surface morphology of the corroded and passive layers of Zn and its alloys were examined utilizing X-ray diffraction (XRD), scanning electron microscope (SEM), and X-ray spectroscopy analysis (EDAX). Potentiodynamic curves show the active–passive transition for all investigated electrodes. The active dissolution and passive currents are gradually decreased as an increase of indium addition to Zn. This explains that the formed film on the surface of alloy becomes better protective than that formed on the surface of zinc. The values of activation energy (Ea) for both active and passive regions increased with the increase of the content of indium, and consequently, the smallest dissolution rate was detected at 1% In. The data obtained from the potentiostatic measurements confirm the results which are obtained from the potentiodynamic ones, where the mixing of indium to Zn diminishes the current density of both active and passive regions. XRD, SEM, and EDX analysis exhibited that the corrosion products on the surface of pure zinc are Zn(OH)2 and ZnO. While ZnO as well as In2O3 are formed on the alloyed zinc surface.

The impact of indium metal as a minor bimetal on the anodic dissolution and passivation performance of zinc for alkaline batteries: part I—potentiodynamic, potentiostatic, XRD, SEM, and EDAX studies