All solid-state batteries (ASSB) are regarded as a promising alternative to replace state-of-the-art liquid electrolyte-based batteries. Lithium-ion containing electrolytes are undoubtedly the most successful chemistries to date. However, taking material abundance into consideration, lithium sources are relatively limited and thus the Li compounds are costly to produce. In contrast, sodium sources are considered readily accessible. This makes sodium battery chemistries attractive and justifies their ongoing development targeting the large-scale energy storage. Until recently, the most widely adopted sodium solid electrolytes are NASICON and β-Alumina, with commercial applications of the latter in niche markets. However, demands for high power and cheaper processing have made the class of electrolytes based on Na₃PS₄ a more promising solid-state electrolyte (SSE) candidate for energy storage and conversion applications. I will discuss the synthesis, modification, interfacial engineering and electrochemical engineering of the ASSB based on this type of electrolytes. New characterization toolkit such as cryo-FIB/SEM and cryo-TEM are indispensable tools for studying the electrode / electrolyte interphases in the room temperature ASSB sodium batteries.