From High‐ to Low‐Temperature: The Revival of Sodium‐Beta Alumina for Sodium Solid‐State Batteries

Abstract Sodium‐based batteries are promising post lithium‐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. The solid electrolyte sodium‐beta alumina shows a unique combination of properties because it exhibits high ionic conductivity, as well as mechanical stability and chemical stability against sodium. Pairing a sodium negative electrode and sodium‐beta alumina with Na‐ion type positive electrodes, therefore, results in a promising solid‐state cell concept. This review highlights the opportunities and challenges of using sodium‐beta alumina in batteries operating from medium‐ to low‐temperatures (200 °C–20 °C). Firstly, the recent progress in sodium‐beta alumina fabrication and doping methods are summarized. We discuss strategies for modifying the interfaces between sodium‐beta alumina and both the positive and negative electrodes. Secondly, recent achievements in designing full cells 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.