A Review on the Electroless Deposition of Functional Materials in Ionic Liquids for Batteries and Catalysis

Abstract

Developing functional materials via electroless deposition, without the need of external energy is a fascinating concept. Electroless deposition can be subcategorized into galvanic displacement reaction, disproportionation reaction, and deposition in presence of reducing agents. Galvanic displacement reaction is a spontaneous reduction process wherein the redox potentials of the metal/metal ion in the electrolyte govern the thermodynamic feasibility of the process. In aqueous solutions, the galvanic displacement reaction takes place according to the redox potentials of the standard electrochemical series. In comparison, in the case of ionic liquids, galvanic displacement reaction can be triggered by forming metal ion complexes with the anions of the ionic liquids. Therefore, the redox potentials in ILs can be different to those of metal complexes in aqueous solutions. In this review, we highlight the progress in the electroless deposition of metals and semiconductors nanostructures, from ionic liquids and their application toward lithium/sodium batteries, and in catalysis.

Building an electrochemical series of metals in pyrrolidinium-based ionic liquids

“…[2][3][4][5][6][7][8][9][10] Recently, some unusual ndings where a less noble metal is deposited on a more noble metal by electroless deposition, that is, a galvanic displacement reaction, have been reported. [11][12][13] As Lahiri et al pointed out, these kinds of galvanic displacement reactions could be triggered by forming metal ion complexes with the anions of ionic liquids, making the redox potentials in ionic liquids different to those of metal complexes in aqueous solution. 13 An electrochemical series in an aqueous system has been well established, and is available in the form of a standard electrode potential database.…”

Electrochemistry of Neodymium in Phosphonium Ionic Liquids: The Influence of Cation, Water Content, and Mixed Anions

“…Other variables that may have an impact include the chemistry of the electrolyte and substrate, speciation, and the nature of the electrode/electrolyte interface. [41,42]…”

Electrodeposition of Tin onto Zinc for the Electrochemical Synthesis of Zn/Sn/Cu Precursor Stack for CZTS‐Based Photoconversion Devices

“…[6] Also, a significant variation from the standard electrochemical series, defined for the aqueous environment, is expected due to the formation of complexed species between the organic solvent and the metal cations. [7] These features suggest the possibility to overcome the limitations of water-based solution due to pH-dependent effects and differences in reduction potentials, allowing to form coatings on reactive substrates. [8] In this context, the exploitation of organic solvents may allow the fabrication of metallic multilayers, intrinsically incompatible with aqueous chemistry, when reactive elements are involved.…”

“…This characteristic typically results in reduction processes with high faradaic efficiency that, besides being advantageous from an energetic viewpoint, limits the detrimental effect of hydrogen evolution on coating morphology and properties . Also, a significant variation from the standard electrochemical series, defined for the aqueous environment, is expected due to the formation of complexed species between the organic solvent and the metal cations . These features suggest the possibility to overcome the limitations of water‐based solution due to pH‐dependent effects and differences in reduction potentials, allowing to form coatings on reactive substrates .…”