Novel zinc-antimony alloy as anodes in alkaline batteries in the presence of sulfide ions additive: Practical and computational study

The charge-discharge and corrosion processes of alloyed zinc with antimony in alkaline electrolytes were studied without and with adding sulfide ions. The obtained results reveal that the density of corrosion current (Icorr.) decays gradually, while the efficiency value of inhibition rises as a result of increasing S2- ions concentration. The process of an anodic reaction is more impacted than that of a cathodic one by adding S2- ions to the electrolyte. In addition, the presence of S2- ions can reduce ZnO and Sb2O3 produced on each surface of the two studied electrodes. The results showed that inhibition efficiency is also increased by raising the solution temperature containing the tested alloy's S2- ions (1 x 10-3 M). This observation reflects that the type of S2- ions adsorption on the surface is chemical, and the additive species' adsorption process follows the Langmuir model. The data of charge-discharge investigation revealed that the longest discharge times of the two studied electrodes were obtained when S2- ions were present in the highest concentration (1 x 10-3 M). However, alloy II displayed a longer time and a bigger potential difference than alloy I. This illustrates that the addition of K2S helps suppress hydrogen evolution. Therefore, the self-discharge can be diminished, and the discharge capacity increased. The alkaline battery's over-potential catalytic reaction is remarkably reduced, and the battery's cyclic stability is improved. These results confirm that the addition of S2- ions has significantly improved the studied alloy utilization as an anode in alkaline batteries. The DFT theoretical study revealed that S2- ion is possessed at low Delta Egap. This can contribute to the inhibition process through chemical adsorption.