A new method to determine AgCl(1% mol)/Ag electrode potential versus the standard chloride electrode potential in a LiCl-KCl eutectic

Abstract

In this work, an innovative method was utilized to determine the AgCl(1% mol)/Ag reference electrode potential versus Cl2/Cl− at 673 K. Instead of directly measuring the chlorine electrode potential, the AgCl(1% mol)/Ag electrode potential versus Cl2/Cl− was calculated from the decomposition voltage of LiCl and the equilibrium potential of Li+/Li versus AgCl(1% mol)/Ag in a LiCl-KCl melt. The decomposition voltage of LiCl in the LiCl-KCl melt was calculated using the Nernst equation and the equilibrium potential of Li+/Li was determined by chronopotentiometry, open circuit chronopotentiometry and potentiodynamic scan techniques, and the deviation is within 5 mV. The AgCl(1% mol)/Ag electrode potential was determined to be −1.130 V vs Cl2/Cl− at 673 K. Since it does not involve direct injection of chlorine gas, this method is more convenient and safer than existing approaches. Furthermore, it also has the potential to be used to calibrate reference electrodes in a variety of melts.

Keywords

• AgCl/Ag electrode potential
• Standard chlorine electrode potential
• Molten chlorides