Electrodeposition of Zinc from Choline Chloride-Ethylene Glycol Deep Eutectic Solvent: Effect of the Tartrate Ion

The use of deep eutectic solvents (DES) for metal electrodeposition has become an area of interest in the recent years however the use of additives on the electrodeposition from deep eutectic solvents is still an unexplored area. In this study we describe the influence of the tartrate ion on the deposition mechanism of zinc and on the resultant morphology of the deposits. Electrochemical techniques were used to characterize the deposition process and scanning electron microscopy was used to study the deposit morphology. It is shown that the presence of potassium hydrogen tartrate in ethaline does not alter the generic voltammetric profile of zinc in solution but in contrast the presence of tartaric acid cause major modifications. From the analysis of the chronoamperometric transients a 3D progressive nucleation mechanism is proposed for the deposition of zinc in absence and in the presence of potassium hydrogen tartrate. In the presence of tartaric acid a 2D progressive nucleation mechanism is proposed for the initial part of the deposition then changing to a 3D progressive mechanism. The SEM images reveal that both additives change the morphological characteristics of the deposits. However the use of tartaric acid introduces a more dramatic change.