The effect of anions on the solid/ionic liquid (IL) interface and the electrodeposition of zinc have been investigated. The employed ILs are composed of 1-ethyl-3-methyl­imidazolium ([EMIm]+), bis­(trifluoro­methyl­sulfonyl)­imide (TFSI–), trifluoro­methyl­sulfonate (TfO–), methyl­sulfonate (OMs–) and acetate (OAc–). These anions show an increasing cation–anion interaction strength in the order TFSI– < TfO– < OMs– < OAc–, as probed by far-infrared spectroscopy below 200 cm–1. It was shown by in situ AFM that the anion has a profound impact on the interfacial properties. Multilayered structures were observed at the electrode/IL interface for [EMIm]­TFSI and [EMIm]­TfO, respectively, while only a few layers with rather a low push-through force were found at the interface for [EMIm]­OMs and [EMIm]­OAc, respectively. The coordination of Zn­(II) ions in these ILs by varying zinc salts was investigated by Raman spectroscopy. The differences in metal species and interfacial layers have a strong influence on the electrochemical process and on the quality of the deposits. Dense zinc deposits with nanowire-like and hexagonal plate-like structures were obtained from ILs with TFSI– and TfO– anions, respectively. Thin layers of zinc with porous and spongy structures were obtained in ILs with OMs– anion containing 0.2 mol/L zinc salts, while homogeneous and smooth deposits with a fine-grained structure were obtained with 1 mol/L zinc salts. However, no deposits were found in Zn­(OAc)2/[EMIm]­OAc under the same conditions. These results indicated that the anions of ILs strongly affected the solid/IL interface, the speciation of Zn­(II) ions in ILs, and the morphology of zinc deposits.

In this paper, we report on the electrodeposition of zinc from the ionic liquid 1‐ethyl‐3‐methylimidazolium acetate ([EMIm]OAc) with various concentrations of zinc acetate [Zn(OAc)2] at 100 °C. The electrochemical behavior of zinc complexes in [EMIm]OAc was determined by cyclic voltammetry. Raman and infrared spectroscopy were employed to study the coordination of Zn2+ ions with OAc−, and it was found that upon increasing the Zn(OAc)2 concentration the intensity of the band for the free acetate anion weakened, due to binding with Zn2+ ions. A minimum concentration of 4 m Zn(OAc)2 was required to observe bulk zinc deposition, and in that case, the reducible species present in the solution were probably a mixture of Zn(OAc)2 and Zn(OAc)+. Furthermore, the scanning electron microscopy results revealed microcrystals of zinc composed of many nanostructures distributed on the substrate, and X‐ray diffraction analysis indicated that a Zn–Au alloy along with Zn films was obtained.

In the present paper, vertically aligned arrays of zinc nanowires were synthesized by electrochemical deposition into ion track-etched polycarbonate membranes in the ionic liquid electrolyte 1-ethyl-3-methylimidazolium trifluoromethylsulfonate ([EMIm]TfO)/Zn(TfO)2. Cyclic voltammetry and chronoamperometry were performed to investigate the electrochemical growth of zinc nanowires inside of the membranes. The transport processes and mechanisms of the nanowire growth in the membranes are also discussed. A supporting zinc or copper layer was deposited on the sputtered side in order to make the back layer thick enough to stabilize the wires. Zinc nanowires with a diameter of 90 nm and a length of up to 18 μm were obtained after removing the template. Furthermore, short nanowires with lengths less than 5 μm and a sandwich-like structure with nanowires in the middle were also synthesized. Vertically aligned zinc nanowire structures on such a substrate might be a potential anode candidate for future generation lithium ion batteries.

In this paper, the influence of various concentrations of water on the electrochemical and spectroscopic behavior of 1-ethyl-3methylimidazolium acetate ([EMIm]OAc) and of 1 M Zn(OAc) 2 /[EMIm]OAc has been investigated. The results show that the added water can reduce the viscosity and improve the conductivity of the employed electrolyte. Spectroscopy results reveal that both [EMIm]OAc and 1 M Zn(OAc) 2 /[EMIm]OAc interact with water and the extent of interaction varies with the amount of water. Furthermore, the electrochemical behavior of 1 M Zn(OAc) 2 /[EMIm]OAc is changed with the addition of different concentrations of water. A minimum of 20 vol% water was necessary to electrodeposit Zn from 1 M Zn(OAc) 2 /[EMIm]OAc at room temperature. Moreover, 1 M Zn(OAc) 2 /[EMIm]OAc with 20 vol% water was assessed for its possible application as an electrolyte in a Zn-air battery.

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