Zinc Electrodeposition from a Deep Eutectic System Containing Choline Chloride and Ethylene Glycol

Abstract

Deep eutectic electrolytes have recently been considered as alternatives to classical room-temperature ionic liquids. This work is an initial study of the zinc deposition process from a basic choline chloride/ethylene glycol deep eutectic solvent containing ZnCl2 at 30°C . The system was examined by cyclic voltammetry at static and rotating glassy carbon disk electrodes and by potential step techniques. There was little deposition initially on sweeping or stepping the potential to −0.5 to −0.8 V vs Zn/Zn(II), but more rapid deposition was observed when the potential was subsequently raised to −0.4 to −0.2 V. The role of choline chloride was also studied by comparing with a choline-free electrolyte, which exhibited a more conventional voltammetric response. The formation of a dissolved, intermediate species Z on the cathodic sweep was proposed to account for the observed deposition behavior in the deep eutectic. Furthermore, an observation of the electrodeposition behavior with the addition of sodium ethoxide supports the suggestion that Z is a complex of Zn2+ and deprotonated components of the solvent.

Low melting mixtures in organic synthesis – an alternative to ionic liquids?

“…3 Table 14 shows the conductivities observed in DESs which are comparable to ionic liquids; 44,45 DESs are therefore a highly investigated medium for electrochemical applications. [46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63] Readers interested in electrodeposition from ILs and DESs will find a good review in ref. 64.…”

Studies Regarding the Nickel Electrodeposition from Choline Chloride Based Ionic Liquids

“…Critical surface coverage necessary for the transition from nucleation to bulk growth is similar for both liquids. Whitehead et al (Whitehead et al, 2010) have investigated the zinc deposition process from a basic choline chloride/ethylene glycol deep eutectic solvent containing ZnCl 2 at 30°C. On sweeping or stepping the potential to −0.5 to −0.8 V vs. Zn/Zn(II), only little deposition takes place initially, with a more rapid deposition being observed when the potential was subsequently raised to −0.4 to −0.2 V. The role of choline chloride was also studied by comparing with a choline-free electrolyte, which exhibited a more conventional voltammetric response.…”

Main chemical species and molecular structure of deep eutectic solvent studied by experiments with DFT calculation: a case of choline chloride and magnesium chloride hexahydrate

“…Ionic liquids analogous, known as deep eutectic solvents (DESs), have been recognized as an alternative to traditional solvents and ionic liquids [1][2][3][4]. The so-called DESs exhibit some properties similar to ionic liquids such as a wide electrochemical window, a low vapor pressure, etc.…”