Effect of water presence on choline chloride-2urea ionic liquid and coating platings from the hydrated ionic liquid

Abstract

In the present study, hygroscopicity of the choline chloride-urea (ChCl-2Urea) ionic liquid (IL) was confirmed through Karl-Fisher titration examination, indicating that the water content in the hydrated ChCl-2Urea IL was exposure-time dependent and could be tailored by simple heating treatment. The impact of the absorbed water on the properties of ChCl-2Urea IL, including viscosity, electrical conductivity, electrochemical window and chemical structure was investigated. The results show that water was able to dramatically reduce the viscosity and improve the conductivity, however, a broad electrochemical window could be persisted when the water content was below ~6 wt.%. These characteristics were beneficial for producing dense and compact coatings. Nickel (Ni) coatings plating from hydrated ChCl-2Urea IL, which was selected as an example to show the effect of water on the electroplating, displayed that a compact and corrosion-resistant Ni coating was plated from ChCl-2Urea IL containing 6 wt.% water doped with 400 mg/L NA at a moderate temperature. As verified by FTIR analysis, the intrinsic reason could be ascribed that water was likely linked with urea through strong hydrogen bond so that the water decomposition was suppressed during plating. Present study may provide a reference to prepare some similar water-stable ILs for plating.

Water in Rechargeable Multivalent‐Ion Batteries: An Electrochemical Pandora's Box

“…The AlCl 3 /ionic‐liquid electrolytes are sensitive to water, exhibiting H 2 evolution at a more positive voltage onset for as low a H 2 O concentration as 7500–10 000 ppm, which implies that their manipulation in battery assembly lines should be restricted to controlled dry environments . Nonetheless, water has been shown to inhibit dendrite formation in Ni electrodeposition by using choline chloride/urea mixtures, which display a compact and corrosion‐resistant electrodeposited film by using an electrolyte containing 6 wt % water …”

Surface Sensitive Nickel Electrodeposition in Deep Eutectic Solvent

“…In the case of nickel, different structures were found depending on both the DES composition and substrates employed. [38][39][40][41][42][43][44][45][46][47] Recently, Ustarroz et al investigated the nickel deposition on glassy carbon using a ChCl/urea based DES and described that nickel deposition involved the formation of nanostructures. 48 Here, we investigated in detail the electrodeposition of nickel in a DES based on the mixture ChCl/urea.…”

Electrochemical deposition of zinc coatings from the ionic liquid based on choline chloride

“…It is worth noting that one of the problems cited in the review [4] of ionic liquids is high hygroscopicity. Research results in the work [7] show that the absorption of atmospheric moisture by the reline system is reversible with prolonged exposure of the ionic liquid at 80 °C, which allows to work with electrolytes based on it without use inert atmosphere.…”