Anodic Reactions and the Corrosion of Copper in Deep Eutectic Solvents

Abstract

An analysis of the anodic reaction occurring at soluble copper anodes during the electrodeposition of copper from an ethaline-based deep eutectic solvent (DES) has been performed. It was shown by UV-Vis spectroscopy and electrochemical measurements that the dominant anodic species produced is the CuCl 2 -complex. In pure ethaline the current efficiency of the anodic process is 100% and the dissolution valency is one. However, in the presence of Cu(II) species the apparent dissolution valency measured gravimetrically was typically less than unity, corresponding to an observed mass loss greater than that expected from Faraday's law.Moreover, the apparent dissolution valency showed a marked dependence on the electrode

Solvometallurgical recovery of cobalt from lithium-ion battery cathode materials using deep-eutectic solvents

“…The peak shapes and the wavelengths of maximum absorbance of copper(I) chloride and copper metal are quite similar, indicating that copper(I) chloride complexes are probably predominantly formed during leaching of LiCoO 2 with aluminium and copper by the choline chloride-citric acid DES. The dissolution of copper metal in a choline chloride-ethylene glycol DES is described by Green et al 80 These authors describe the comproportionation/disproportionation equilibrium between copper (I)and copper(II) chlorides, with the former being the dominant species. This is supported by the smaller absorption band at about 405 nm, which is characteristic for the tetrachlorocuprate(II) complex.…”

“…This is supported by the smaller absorption band at about 405 nm, which is characteristic for the tetrachlorocuprate(II) complex. 48,80,81 The intensity of this absorption band decreases when copper(I) chloride is dissolved but is still slightly present, indicating the copper(I)-copper(II) equilibrium. 80 Moreover, the copper(II) oxidation state is stable in aqueous media, even at low chloride concentrations whereas monovalent copper(I) is only stable at higher chloride concentrations (≥1 mol L −1 , [82][83][84] like in the DES).…”

Mechanism of selective gold extraction from multi-metal chloride solutions by electrodeposition-redox replacement

“…In the 1 : 2 ChCl : EG solution, comproportionation reaction (eqn (16)) provides a plausible explanation for the oxidation of copper at the early RR stage in 1 : 2 ChCl : EG: 64,65 Cu þ CuCl 4 2À ! 2CuCl 2…”

Novel Electropolishing of Pure Metallic Titanium in Choline Chloride-Based Various Organic Solvents

“…17,18 Deep eutectic solvents (DESs) are eutectic liquid mixtures of complex systems of variety of ions, for instance choline chloride and ethylene glycol. 19,20 In the present study, the impact of electrolyte composition on electropolishing of pure metallic titanium as one of invaluable metals is addressed. It is also essential to answer an importance of usage of environmentally benign electrolytic bath in the electrochemical polishing.…”