Polarization Effects on Meniscus Characteristics in Molten Carbonate

Abstract

Meniscus heights on a gold flag electrode partially submerged in Li/K carbonate (62/38 mole percent) at 650°C have been determined under a variety of gas mixtures at atmospheric pressure. The meniscus height as a function of electrode potential shows a characteristic minimum for each gas composition and a relatively steep increase with increasing cathodic polarization. Analysis of the near‐equilibrium data, assuming electrocapillary effects only, shows that this is consistent with specific adsorption of oxide ion on the electrode. At appreciable polarization, mass‐transfer effects as well as adsorption appear to play a role, and the approach to steady‐state conditions following a disturbance is slow.