Reduction potentials of alkali metal ions (Li+, K+ and Na+) in LiCl-KCl and LiCl-KCl-NaCl melts

摘要

The cyclic voltammetry and square wave voltammetry were employed to determine Li+, K+, Na+ reduction potentials in LiCl-KCl and LiCl-KCl-NaCl melts at 450-600 °C. In KCl-LiCl (1:1 to 7:3 molar ratio) melt, Li ion was reduced prior to K. ion and its reduction potential was dependent on temperature, shifting positively to about 0.2 V as temperature changing from 450 to 600 °C, and K ion onset reduction potential was varied with composition, shifting positively about 0.22 V as composition changed from 1:1 to 7:3 molar ratio. Therefore, the difference in K and Li ion reduction potential in LiCl-KCl melt decreased as temperature increased and the molar ratio of KC1 to LiCl increased, and slightly higher than the value obtained from the Nernst Equation. Na ion presented a 0.2 V more positive potential than Li ion in LiCl-KCl (1:1 molar ratio)-(0.28 mol/L) NaCl melt that did not obey the Nernst Equation.