Inorganic Sodium Solid-State Electrolyte And Interface With Sodium Metal For Room-Temperature Metal Solid-State Batteries

Metal solid-state batteries are regarded as the next-generation energy storage systems with high energy density and high safety. A robust and intimate solid-state interfacial contact between the sodium metal with the solidstate electrolyte (SSE) is vital to achieve good cyclic stability at high current density. However, inorganic SSEs suffer from poor stability when cycling at a current density below 2 mA cm(-2). This can be ascribed to the dendrite formation through the SSE due to plating process or void formation during the stripping process. Furthermore, simply direct application of a sodium metal on SSE shows poor interfacial contact and low critical current density. In this review, the recent development of inorganic sodium-ion electrolytes, such as oxide-, sulphide-, and halide-based, are briefly discussed. More particularly, the dendrite formation through the SSE and the loss of solid-solid contact at the sodium/SSE interface are reviewed. Additionally, different engineering approaches to integrate the sodium metal with the solid-state electrolytes and its correlation with the electrochemical performance are discussed. Finally, perspectives in future researches are identified.