Electrochemical Behaviors and Thermodynamic Properties of Ce on Liquid Bi, Sn, and Zn Electrodes in Molten LiCl-KCl Salt

Abstract

This study presents the electrochemical behaviors and thermodynamic properties of Ce on liquid Bi, Sn, and Zn electrodes in molten LiCl-KCl eutectic salt. First, the Ce-metal binary systems on the solid tungsten electrode were investigated to determine the formation of Ce-metal intermetallic compounds during the electrowinning process. In these experiments, the formation of five Ce-Bi intermetallic compounds, eight Ce-Sn intermetallic compounds, and nine Ce-Zn intermetallic compounds was confirmed from the oxidation peaks of cyclic voltammetry. The standard Gibbs free energy of formation of each intermetallic compound was calculated from plateaus of the open-circuit chronopotentiometry. Subsequently, the electrochemical behaviors of Ce were investigated on liquid Bi, Sn, and Zn electrodes using cyclic voltammetry. In particular, while the reduction potentials of Li and Ce were too close to differentiate on the liquid Bi and Sn electrodes, they were not on the liquid Zn electrode. Peak potentials from cyclic voltammetry were utilized to calculate the activity coefficients of Ce in the liquid Bi, Sn, and Zn electrodes, which were 3.16×10-14, 1.82×10-12, and 9.05×10-10, respectively.

Determination of the Diffusion Coefficient in Electrodeposition Reactions by Electrochemical Impedance Spectroscopy: A Case Study of Cobalt in Molten LiCl-KCl Salt

“…Additional information about the liquid working electrode configuration is described in elsewhere. 16 The presence of the surrounding quartz tube ensured that the guiding W rod did not participate in the electrochemical reaction in the molten salt. This was verified by visually monitoring the surface of the guiding W rod during the electrodeposition of Co metal onto the liquid Bi working electrode.…”

Electrochemical and kinetic studies on the electrolytic extraction of Gd on Bi electrode in LiCl–KCl melt

“…1a displays the cycle voltammetry (CV) curves of LiCl-KCl-BiCl 3 melt before and after the addition of GdCl 3 . Three pairs of reaction peaks (A/A 0 , C/C 0 and B/B 0 ) observed from the black curve are attributed to the reduction/oxidation of metal Li, metal Bi and Bi-Li intermetallic compound, 25,26 while three new reduction peaks (D, E and F) detected at À2.03, À1.59 and À1.29 V on the red curve are associated with the formation of metal Gd and Gd-Bi alloys. 27,28 To further investigate the generation of Gd-Bi alloys, CVs with various potential windows were conducted in LiCl-KCl-BiCl 3 -GdCl 3 melt.…”

“…underpotential deposit), the significant reaction potential differences between the two electrodes can be clearly observed. 25,32 Moreover, the absence of any other reaction peaks on the red CV curve indicates that no intermetallic compounds were produced. The absence of intermetallic compound formation can be attributed to the Gd monolayer that diffuses continuously from the surface into the interior of the liquid Bi electrode, thereby preventing the formation of Gd-Bi alloys.…”

Electrochemical Extraction of Fission Element Samarium from Molten NaCl-2CsCl Eutectic Salt Using the Liquid Gallium Cathode

“…Therefore, electrolytic refining using high-temperature molten salt as medium is considered as the most promising way of spent fuel reprocessing, which can effectively separate the rare earth elements according to the different redox potential. Currently, the precipitation potential, current, and separation factor of Lns on different cathodes have been examined by molten salt electrolytic refining, including Al, − Ga, , Pb, , Zn, , Bi, , Sn, , and other electrodes, which provide basic theoretical support for the extraction and separation of Lns and Ans. Among many cathode materials, Ga, a liquid metal with a low melting point (29.8 °C) and ease of recycling, is considered as a promising reactive electrode material.…”