Advancing NASICON-structured solid-state sodium-ion batteries through compositional and interfacial engineering

Abstract

NASICON-type ceramics are promising solid electrolytes (SEs) for next-generation solid-state batteries (SSBs), but their practical application is constrained by moderate ionic conductivity and high interfacial resistance. This article reviews recent advancements in overcoming these challenges through a dual strategy: (1) compositional engineering—via co-doping Na₃Zr₂Si₂PO₁₂ with Yb/Sc, Ce/Sc, and Mg/Si—to enhance Na⁺ conductivity through structural modifications; and (2) interfacial engineering—including wetting agent insertion, composite cathode formation, and the use of infiltrated cathodes—to enlarge interfacial solid–solid contact between cathode and rigid SE and improve electrochemical stability. By integrating these approaches, this work offers a unified framework for the rational design of NASICON-based SSBs. Importantly, SSBs incorporating Mg/Si co-doped NZSP as the SE, a Na metal anode, and an infiltrated cathode achieve high active mass loading (∼2.2 mg cm⁻²), with an initial discharge capacity of 103.8 mA h g⁻¹ at 0.2C and 95% retention after 50 cycles. Finally, this article provides a road map outlining key milestones and future research directions for advancing NASICON-based SSB technology.