The Electrochemical Behavior of Tellurium Tetrachloride in LiCl-KCl Eutectic Molten Salt at 450 °c

Cyclic voltammetry CV), square wave voltammetry (SWV), and electrochemical impedance spectroscopy measurements were carried out in 1 and 5 wt% TeCl4 containing LiCl-KCl eutectic molten salt at 450 °C using tungsten and glassy carbon as working electrodes. Reduction of Te(IV) to Te(0) occurred in three steps at potentials more negative than -0.4 VAg/AgCl. The Te(0) was further reduced to Te2- at more negative potentials. Formation of Te2- was observed at potentials more negative than -2.2 VAg/AgCl. Diffusivities of Te4+, Te2+, and Te2- and their formal potentials were estimated from the CV data. The diffusion coefficients of Te4+, Te2+ and Te2- were 0.9 × 10-5, 3.8 × 10-5, and 1.5 × 10-5 cm2 s-1, respectively in the 1 wt% TeCl4 containing LiCl-KCl molten salt. The diffusivity of Te species generally decreased with increase in the concentration of TeCl4.