Solid electrolyte for high energy density batteries

High energy density batteries, consisting of sodium/sodium polysulfide electrochemical couples, separated by the ion conducting ceramic electrolyte sodium beta- alumina, are now at the stage where commercialization is realistic. The detailed study of the various degradation processes occurring in the solid electrolytes have been shown to be avoidable by microstructural control of the electrolytes, limiting the grain size to below 50 micron everywhere by controlling the contamination levels of the system during operation, and by proper cell design that avoids current heterogeneity.