Electrodeposition of rhenium with suppressed hydrogen evolution from water-in-salt electrolyte

The electrodeposition of rhenium was studied using a “water-in-salt” type of electrolyte with a superhigh concentration of lithium chloride to suppress the proton activity. Cyclic voltammetry and DC plating were carried out on rotating disc electrodes to characterize the electrolyte and to prepare thin films. Electrolytes without metal cations were also studied, where the cathodic reduction of proton was significantly suppressed when the concentration of supporting salt approached the solubility limit. Film cracks were eliminated for rhenium films deposited from this superhigh ionic strength electrolyte.