A Promising Crystalline KCl: Electrolyte Material for Studying the Electrochemical Properties of Cerium on Liquid Indium Electrodes

Abstract

Potassium chloride crystals are good conductors in the UV to mid-infrared broadband and can be widely used as materials for high-power CO2 lasers. However, the most important use of potassium chloride crystals has been overlooked; their stable chemistry and wide electrochemical window allow them to form molten eutectic salts with other chlorides for the dry reprocessing of spent fuel. The aim of this work is to investigate the electrochemical properties of the actinide substitute cerium metal on liquid indium media in order to provide basic data for further realization of lanthanides (Ln)/actinides (An) separation. In this paper, we investigated the electrochemical behavior of 3LiCl-2KCl-CeCl3 melt at liquid metal media indium (In) electrode using various transient electrochemical analysis methods, such as cyclic voltammetry, square wave voltammetry and open circuit potential technique. The quasi-equilibrium potentials of Ce3+ at different temperatures on the liquid metal In electrode were determined. On the redox process, the reaction kinetics of the oxidation–reduction process in the 3LiCl-2KCl-CeCl3 system is studied. It was determined that the reduction of Ce3+ at the liquid metal In electrode is an irreversible single-step process with three electron transfers. The relationship between the diffusion coefficient and the reduction process of Ce3+ ions on liquid metal indium electrodes at different temperatures was determined. The expression for the diffusion coefficient and temperature of Ce3+ at the liquid metal indium electrode is: lnD = 1.43 − 7974.69/T.