ChemInform Abstract: Oxygen Activity and Asymmetric Polarization at the Sodium/β′′-Alumina Interface

ChemInform Abstract

have been studied by cyclic voltammetry with Na/β''-Al2O3/Na cells. It is shown that contamination of the Na electrode by oxygen, as O₂ or H₂O, leads to asymmetric polarization. The observed polarization is quite severe in the range 150-200 °C. The increased interfacial resistance is ascribed to the chemisorption of an oxide or hydroxide layer at the conduction planes of the electrolyte. The adsorption/desorption behavior of the resistive layer is described by a simple Langmuir model. Asymmetric polarization can be effectively eliminated by the use of carefully dried electrolyte tubes and either electrolytic Na or Na from which the oxygen has been scavenged with titanium sponge.