Current pulse measurement of capacitance during molten salt electrochemical experiments

Abstract

In earlier work in our laboratories, a current pulse method was developed that allows in situ (dynamic) measurements of electrode capacitance. The present work describes the successful application of the technique to the study of electrode properties in molten salt electrolytes. As expected, the electrode capacitance increases as the electrode surface area exposed to a molten salt bath increases. Furthermore, creep of the bath along the surface of a conductive ceramic anode and subsequent ingress into the anode pores is observed as an increase in capacitance. The pulse technique also gives an indication of phase changes that occur during the reduction of a solid titanium dioxide cathode and a highly sensitive measure of the temperature at which initial freezing of the calcium chloride electrolyte begins. These observations provide useful in situ information about changes in electrode properties in molten salt electrolytes that are difficult to obtain from other techniques.