SOLID ELECTROLYTE MATERIAL INCORPORATING BETA-ALUMINA CERAMIC, ITS MANUFACTURE AND SODIUM-SULPHUR CELLS AND OTHER ENERGY CONVERSION DEVICES UTILISING SUCH MATERIAL

摘要

Beta-alumina electrolyte material for use in a sodium sulphur cell is protected, on the side exposed to sodium, by a thin coating of an ionically conductive material which will conduct sodium ions. The coating may be for example a glass such as a sodium oxide silica glass or a sodium oxide phosphoric oxide glass. Other glass compositions are described in the specification. As another example the material may be formed by calcining a sodium-doped sol or sol-gel applied to the surface, for example a sodium-doped alumina sol. Another technique comprises applying a solution or dispersion of a suitable sodium compound such as sodium tetraborate or sodium silicate or sodium phosphate, to the surface and firing after evaporating the solvent.