Strategies to Enhance Ionic Conductivity of Na3Zr2Si2O12 Solid Electrolyte for Advanced Solid-State Sodium Batteries

Abstract

Solid-state sodium batteries (SSSBs) have been highly prized as a promising alternative to conventional battery systems using organic liquid electrolytes due to their improved safety, higher energy density, and substantial resources and low cost of sodium. Na₃Zr₂Si₂PO₁₂ (NZSP) solid electrolyte is attracting considerable interest owing to its excellent thermal and chemical stability and favorable compatibility with Na metal anode and high-voltage cathode. However, two main challenges of poor room-temperature ionic conductivity and high interfacial resistance limit the application of NZSP electrolyte in SSSBs. So far, intensive efforts have been devoted to developing modification strategies to improve the room-temperature ionic conductivity of NZSP. This review aims to provide a comprehensive summary and discussion of some optimization strategies for enhancing the room-temperature ionic conductivity of the NZSP solid electrolyte. These optimization strategies are categorized into foreign-ion doping or substitution, sintering behavior modulation, and regulation of chemical composition based on precursors, and their optimization mechanisms are also elaborated. Finally, the prospects of NZSP-based solid electrolytes are presented. This review is expected to offer better guidance for designing and developing high-performance NZSP-based solid electrolytes for accelerating the practical application of SSSBs.