From high- to low-temperature: The revival of sodium-beta alumina for sodium solid-state batteries

Sodium-based batteries are promising post Li-ion technologies because sodium offers a specific capacity of 1166 mAh g-1 and a potential of -2.71 V vs. the standard hydrogen electrode. Pairing a sodium negative electrode and the solid electrolyte sodium-beta alumina, which exhibits a unique combination of properties, with Na-ion type positive electrodes results in a unique solid-state cell concept. This review highlights opportunities and challenges related to the use of sodium-beta alumina in batteries operating from medium- to low-temperature (200 °C - 20 °C). Firstly, the recent progress in sodium-beta alumina fabrication and doping methods are summarized, followed by a discussion on strategies for modifying the interfaces between sodium-beta alumina and both electrodes. Secondly, recent achievements in designing batteries with sodium-beta alumina are summarized and compared. The review concludes with an outlook on future research directions. Overall, this review shows the promising prospects of using sodium-beta alumina for the development of solid-state batteries.