Effect of ionic liquid additive [BMIM]HSO4 on zinc electrodeposition from impurity-containing sulfate electrolyte. Part I: Current efficiency, surface morphology, and crystal orientations

摘要

The effects of ionic liquid additive 1-butyl-3-methylimidazolium hydrogen sulfate-[BMIM]HSO_4 on the current efficiency (CE), surface morphology, and crystallographic orientations during zinc electrodeposition from acidic sulfate solutions containing some common impurities such as copper, iron, cobalt, nickel, and lead were investigated. The results indicated that all the metallic impurities studied exerted a deleterious effect on the zinc electrodeposition process by decreasing the CE, influencing the purity, and inducing changes in morphology of the cathodic deposits. The addition of [BMIM]HSO_4 was observed to relieve the harmful effects of these impurities to some extent, and led to reduce the impurity content in the zinc deposits and improve the CE and the quality of the cathodic deposits. The data obtained from X-ray diffraction revealed that the presence of these impurities alone and in combination with [BMIM]HSO_4 did not change the structure of the electrodeposited zinc but affected the crystallographic orientation of the crystal planes.