Evaluation of Physicochemical Properties and Metal Electrodeposition from Deep Eutectic Mixtures based on Choline Chloride and Cobalt Chloride Hexahydrate

Deep Eutectic Solvents (DESs) are a novel class of liquid mixtures exhibiting tunable physicochemical properties as a function of the nature and ratio of their components. In this paper, we present the preparation and characterization of mixtures with different molar ratios of choline chloride – cobalt chloride hexahydrate, a system that is reported to form a DES. To define the physicochemical nature of the mixtures, their phase transitions have been studied in detail by Differential Scanning Calorimetry (DSC). Furthermore, the characterization of the systems also included measurements of physicochemical properties such as thermal stability, electrical conductivity, viscosity, density, and electrochemical window. The dependence on temperature of density and electrical conductivity has also been evaluated. Finally, electrodeposition of a uniform layer of cobalt with a very low content of impurities was achieved. The obtained coatings displayed different morphologies depending on the molar ratio of precursors and experimental conditions.