Electrochemical and Thermodynamic Properties of CeCl3 on Liquid Cadmium Cathode (LCC) in LiCl-KCl Eutectic Salt

Abstract

Electrochemical and thermodynamic properties of Ce3+/Ce on liquid cadmium cathode (LCC) were investigated in LiCl-KCl salt at various temperatures. Cyclic voltammograms only attributing to Ce3+/Ce reaction were obtained by background subtraction method and diffusion coefficients of Ce on the LCC were determined at temperatures ranging from 723 K to 798 K. Furthermore, thermodynamic properties of the Ce-Cd intermetallic compound formations were measured via an open circuit chronopotentiometry technique at temperature from 698 K to 823 K. The linear dependence of the Gibbs free energy of the formation was observed as a function of temperature, from which the enthalpy and entropy of the formation were calculated. Here, activity and partial molar Gibbs free energies of Ce in two phase coexisting states were calculated through the measurement of electromotive force. Tafel and linear polarization were conducted with varying Ce concentration in Cd. The exchange current densities (i0) of Ce on the LCC were calculated from both techniques in LiCl-KCl-1 wt% CeCl3 at 773 K. The resulting data sets of i0 from both methods show a near linear trend of i0 within the solubility limit of Ce in Cd. However, i0 of Ce remains unchanged with increasing Ce concentration beyond the solubility limit.