Impedance and Polarization Measurements in Fused Lithium Chloride‐Potassium Chloride

Abstract

Impedance measurements with a platinum microelectrode in fused eutectic mixture of potassium chloride (41 mole %) and lithium chloride (59 mole %) are described. The residual resistance and capacitance showed frequency dispersion; probable causes are discussed. Most of the metal ions showed a tendency for “predeposition.” The faradaic admittance in the reduction of Pb++, Co++, Ni++, Zn++, and Cd++ ions had a phase angle of the combination greater than 45°, which has been ascribed to the adsorption of metal ions on the electrode surface. After application of an empirical correction for this effect, the faradaic admittance became normal and was used to calculate the rate constants for the above processes. The current‐potential curves showing the polarization behavior in the vicinity of equilibrium potential are described. By a curve fitting method the values of α, the transfer coefficient for the cathodic process, and i o , the exchange current, are computed. These values of i o are, however, much lower than those calculated by using the rate constants obtained from impedance measurements.