Sodium superionic conductors are highly promising as solid electrolytes for all-solid-state sodium batteries, with the capacity to improve energy and power density of liquid-electrolyte-based batteries and to address their safety issues. However, the ionic conductivity of sodium electrolytes remains roughly one order of magnitude lower than that of lithium systems. Herein, we report a synthesis method for a sodium superionic conductor, tetragonal Na₃PS₄, with an ionic conductivity of 3.39 × 10⁻³ Scm⁻¹ at 25 °C—the highest value yet reported among sulfide-type sodium conductors. The high conductivity is achieved through quenching from 700 °C, which introduces sodium vacancies, and annealing at 450 °C, which increases vacancies and expands lattice volume. The phase is comprised of a framework of isolated PS₄ tetrahedra, with partial distribution of Na over 3D pathways. The high intrinsic conductivity together with low grain boundary contribution and soft mechanical properties make Na₃PS₄ a promising candidate for sodium solid electrolytes.

钠超离子导体作为全固态钠电池的固体电解质具有广阔的前景，它具有提高液体电解质基电池的能量和功率密度并解决其安全问题的能力。然而，钠电解质的离子电导率仍比锂系统的离子电导率低约一个数量级。本文中，我们报道了一种钠离子超导体，即四方Na ₃ PS ₄，其离子电导率为3.39×10 ^-3 Scm ^-1的合成方法。在25°C时-硫化物型钠导体中迄今所报道的最高值。通过从700°C淬火（引入钠空位）和在450°C进行退火（增加空位并扩大晶格体积）可实现高电导率。该相由分离的PS ₄四面体的框架组成，其中Na在3D途径中部分分布。高的固有电导率以及低的晶界贡献和柔软的机械性能使Na ₃ PS ₄成为钠固体电解质的有前途的候选者。