POLARIZATION EFFECTS ON MENISCUS CHARACTERISTICS IN MOLTEN CARBONATE

Meniscus heights on a gold flag electrode partially submerged in Li/K carbonate (62/38 mole percent) at 650-degrees-C have been determined under a variety Of O2-CO2 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.