Irradiation-induced defects in β″- and β⁗-alumina examined by 1 MV high-resolution electron microscopy

Abstract

During transmission electron microscope observations of the rhombohedral β″- and β″″-alumina, structural changes due to the loss of some conduction planes takes place as an electron irradiation effect, while the hexagonal counterparts β- and β‴-alumina are relatively stable. Based on the structures of electron-induced defects determined from high-resolution 1 MV EM images, the phenomena are interpreted in terms of the characteristic crystal structures of β″- and β‴'-alumina. The results are discussed in connection with the problem of degradation of β″-alumina solid electrolytes used in the NaS battery system.