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.