Thermodynamics and Kinetics Properties of Lanthanides (La, Ce, Pr, Nd) on Liquid Bismuth Electrode in LiCl-KCl Molten Salt

Abstract

Electrochemical behaviors of lanthanide (i.e. La, Ce, Pr and Nd) chlorides in LiCl-KCl melt were demonstrated via cyclic voltammetry (CV) and open circuit potential (OCP) techniques at temperatures from 723 K to 873 K. An electrochemical galvanostatic intermittent titration technique (GITT) was performed to obtain the thermodynamic data of lanthanide (Ln) on liquid bismuth electrode. The relationship between activity coefficient and temperature were determined. Galvanostatic pulse (GP) and electrochemical impedance spectroscopy (EIS) as the transient measurements were performed to investigate the interfacial processes of Ln(III) on liquid Bi electrode. The exchange current densities j0 of Ln(III)/Ln were determined by fitting and equivalent circuits, that showed the linear relationship with temperature. In addition, the electrodepositions of La and Ce on liquid Bi electrodes were discussed on the formation of alloys. The products of phase composition and microstructure were conducted by XRD and SEM-EDS, respectively.