Electrodeposition Techniques Using Ionic Liquids and Deep Eutectic Solvents

Electrodeposition in ionic liquids (ILs) and deep eutectic solvents (DESs) has emerged as a versatile route for fabricating metal, alloy and composite coatings under mild conditions. Both classes of non-aqueous electrolytes offer a wide electrochemical window, negligible vapour pressure and tunable solvating power for a broad range of metal precursors. By adjusting solvent composition, water content, temperature and electrochemical parameters (potential, current density, deposition time), researchers can control film morphology, composition, grain structure and adhesion. Compared with conventional aqueous baths, ILs and DESs suppress hydrogen evolution, reduce environmental toxicity and enable deposition of metals with highly negative reduction potentials. Applications span corrosion-resistant zinc and nickel alloys for automotive and aerospace parts, magnetic and electronic films, functional nanostructures for catalysis and energy storage, and selective recovery of metals from waste streams. Continued advances in understanding speciation, mass transport and interfacial kinetics are driving the technology towards industrial adoption and sustainable metal-surface engineering.

Research from Nature Portfolio

Recent studies have examined the influence of controlled hydration on the physicochemical properties of choline chloride–urea ionic liquids. It was shown that introducing modest water levels dramatically lowers viscosity and enhances ionic conductivity while retaining a broad electrochemical window. This balance permits the electrodeposition of dense, compact nickel coatings exhibiting superior corrosion resistance. Spectroscopic analysis indicates that water molecules form strong hydrogen bonds with urea, suppressing water decomposition during plating and promoting uniform film growth. These insights into water-mediated tuning of IL properties have laid the groundwork for optimising deposition baths for a variety of transition metals.

Research from all publishers

A comparative study of concentrated ionic fluids investigated whether deep eutectic solvents truly differ from high-chloride brines. By mapping the relationship between fluidity and molar conductivity across a range of chloride-based electrolytes, researchers showed that mass transport scales uniformly with viscosity regardless of solvent classification. Tailoring chloride and water activity was demonstrated to enable selective etching of copper, silver and nickel, highlighting the continuum between DESs and brines for metal processing. Separately, a comprehensive review of DES-based electrodeposition for corrosion protection has emphasised how bath composition, metal ion concentration and deposition parameters influence coating integrity. Precise control over pH, temperature and current density has been used to engineer nanostructured alloy and composite films with tailored porosity and barrier performance, signalling promising pathways for durable, sustainable protective coatings in harsh environments.

Electrodeposition Techniques Using Ionic Liquids and Deep Eutectic Solvents publication trend

The graph below shows the total number of articles in electrodeposition techniques using ionic liquids and deep eutectic solvents across all publications each year (not limited to Nature Index journals).

Technical terms

Ionic liquid: A salt in liquid form at temperatures below 100 °C, comprising bulky organic cations and inorganic or organic anions, noted for wide electrochemical windows and low volatility.

Deep eutectic solvent (DES): A mixture of a hydrogen-bond donor and acceptor that forms a eutectic with melting point far below those of its components, offering facile preparation and bespoke solvation properties.

Electrochemical window: The potential range within which an electrolyte is stable and does not undergo significant oxidation or reduction, critical for depositing reactive metals.

Viscosity: A measure of a fluid’s resistance to flow, inversely correlated with ion mobility and directly affecting mass transport in electrodeposition baths.

Mass transport: The movement of reactive species to and from the electrode surface, governed by diffusion, migration and convection, which dictates deposition rate and uniformity.

Speciation: The distribution of metal ions among different chemical forms in solution, which influences reduction kinetics and deposit composition.

References

1. Effect of water presence on choline chloride-2urea ionic liquid and coating platings from the hydrated ionic liquid. Scientific Reports (2016).
2. Concentrated Ionic Fluids: Is There a Difference Between Chloride‐Based Brines and Deep Eutectic Solvents?. Angewandte Chemie International Edition (2023).
3. Electrodeposition in deep eutectic solvents: Perspectives towards advanced corrosion protection. Applied Materials Today (2025).