Electrodeposition of Superconducting Rhenium with Water-in-Salt Electrolyte

Abstract

Superconductive rhenium films were electrodeposited from a water-in-salt type electrolyte with superhigh concentration of LiCl. Rhenium free electrolytes were also studied with linear sweep voltammetry to further understand the effects of LiCl salt concentration on the ion activity and side reactions. The morphology, crystallographic structures and superconductivity of the electrodeposited Re films were characterized. The hydration of LiCl resulted in a depletion of free water molecules and a decrease of proton reduction. While cracks were ubiquitously observed in films electrodeposited from traditional electrolyte, such cracks are eliminated when water-in-salt is used. An increased critical temperature of 6 K with an improved stability was observed for the Re film deposited from this new type of electrolyte.

Uncharted Waters: Super-Concentrated Electrolytes

“…With only a few exceptions, where super-concentrated electrolytes were used as synthesis media, or supporting electrolytes for electrochemical actuators, sensors or electrodeposition, [92][93][94] majority of the efforts to explore super-concentration were driven by their potential applications in energy storage systems, batteries in particular. Some of the benefits brought by super-concentration has been described in previous sections when discussing their related properties (Figure 4C).…”

Basal-Plane Orientation of Zn Electrodeposits Induced by Loss of Free Water in Concentrated Aqueous Solutions

“…3.0 V has been reported for a 21 mol kg -1 lithium bis(trifluoromethylsulfonyl)amide (LiTf 2 N, Tf = SO 2 CF 3 ) aqueous solution. 5 In such concentrated aqueous solutions, the amount of free water is considerably decreased to suppress water electrolysis, which is beneficial for energy storage, [6][7][8][9][10][11] surface finishing processes, [12][13][14][15][16] and so on. For example, zinc (Zn) electrodeposition from concentrated zinc chloride (ZnCl 2 ) aqueous solutions have demonstrated the suppression of both water decomposition and dendritic growth, which is promising for zinc-air batteries.…”

Rhenium Electrodeposition and Its Electrochemical Behavior in Molten KF-KBF4-B2O3-KReO4

“…The method of rhenium oxides and/or potassium and ammonium perrhenates reduction by hydrogen is the most common [ 5 , 6 ]. Rhenium-based coatings may be obtained by the electrolysis of aqueous solutions of perrhenates and chlorrhenates [ 7 , 8 , 9 , 10 , 11 , 12 , 13 ]. Despite their drawbacks, the described methods are widely used.…”