NASICONs‐type solid‐state electrolytes: The history, physicochemical properties, and challenges

Abstract Solid‐state electrolytes are critical for the development of next‐generation high‐energy and high‐safety rechargeable batteries. Among all the candidates, sodium (Na) superionic conductors (NASICONs) are highly promising because of their evident advantages in high ionic conductivity and high chemical/electrochemical stability. The concept of NASICONs was proposed by Hong and Goodenough et al. in 1976 by reporting the synthesis and characterization of Na 1+ x Zr 2 (Si x P 3 − x )O 12 (0 ≤ x ≤ 3), which has attracted tremendous attention on the NASICONs‐type solid‐state electrolytes. In this review, we are committed to describing the development history of NASICONs‐type solid‐state electrolytes and elucidating the contribution of Goodenough as a tribute to him. We summarize the correlations and differences between lithium‐based and sodium‐based NASICONs electrolytes, such as their preparation methods, structures, ionic conductivities, and the mechanisms of ion transportation. Critical challenges of NASICONs‐structured electrolytes are discussed, and several research directions are proposed to tackle the obstacles toward practical applications.