Effect of Magnesium Ion on the Zinc Electrodeposition from Acidic Sulfate Electrolyte

The effects of Mg²⁺ ion on the zinc electrodeposition were systematically investigated in sulfuric acid solution through the characterizations of current efficiency (CE), power consumption (PC), deposit morphology, cathodic polarization, and cyclic voltammetry. The results demonstrate that there is no significant influence on CE and PC in the Mg²⁺ concentration range of 1 to 10 g L⁻¹, but with a drastic decrease of the CE and rapid increase of PC at Mg²⁺ ion concentration above 15 g L⁻¹. Based on the morphology observation and polarization curves, the presence of Mg²⁺ ions could also induce the coarse surface on the electrodeposited zinc accompanying the enhancement of the cathodic polarization, which becomes more distinct at a high concentration above 15 g L⁻¹. Furthermore, hydrogen evolution could be promoted with the existence of Mg²⁺ ions according to cyclic voltammograms.