Guidelines for making, interpreting, and quantifying activity by electromotive force measurements of molten salts containing mixed cations and anions using cation-based electrodes

Measurements of thermochemical properties in molten salt electrolytes with mixtures of cations and anions are difficult to interpret. Electromotive force measurements of salts containing common anions were driven by the least stable anion compound (e.g., LiCl in LiCl-KCl), while measurements in common cation salts were driven by the most noble anion half-cell reaction (e.g., F-/F2 in LiCl-LiF). Measurements in mixed cation and anion salts were driven by the least stable anion compound for the most noble anion half-cell reaction (e.g., KF in KCl-LiF). These guidelines enable quantification of the activity of electroactive species in salts containing multiple cations or anions.