Effect of additives and current mode on zinc electrodeposition from deep eutectic ionic liquids

Zinc electrodeposition in 'non-aqueous' ionic liquids is recently of interest to avoid hydrogen discharge. This study aimed to demonstrate the effect of organic additives (acetonitrile and ethylenediamine) and current mode on the deposit morphology and grain size of zinc coatings electrodeposited from a deep eutectic ionic liquid based on choline chloride (ChCl) and urea. Cyclic voltammetry (CV) measurements were conducted and the resultant CV diagrams were precisely assessed to understand the effect of additives on the deposition mechanism. The electrodeposition current mode was altered from direct current to pulsed current to study its influence on the deposit morphology. The deposit morphologies and grain sizes were observed using a high-resolution field emission scanning electron microscopy. The results revealed that the deposit morphologies and grain sizes were influenced by the additives. Application of pulsed current was found to be more influential on the deposit morphology. Pulsed current produced smooth, uniform, and fine-grained Zn coats. Applications of additives and pulsed current modified markedly Zn electrodeposition from ionic liquids.