High-conductivity solid electrolytes are crucial components for the development of Na-based solid state batteries. However the electrolyte structure prototype and corresponding synthesis method are still lacking. The conventional oxide and sulfide electrolytes are precursor-expensive (e.g. Na₂S) or energy-intensive in sintering synthesis (e.g. at 1000 ​°C). Here, we propose a novel anti-perovskite solid electrolyte of Na-rich fluorinated sulfate (Na₃SO₄F) benefiting from Mg and Cl co-doping by solid state reaction from low-cost precursors at moderate temperature (500 ​°C). The tailored dual doping enables an improvement of ionic conductivity by three orders of magnitude close to 10⁻⁴ ​S ​cm⁻¹ at 60 ​°C. The creation of Na vacancies (by aliovalent Mg doping) and lattice expansion (by substituting F sites with larger-sized Cl ions) are responsible for the conductivity upgrade. A Na–Sn/Fe [Fe(CN)₆]₃ solid state battery based on Na_2.98Mg_0.01SO₄F_0.95Cl_0.05 electrolyte can reversibly run with a first discharge capacity as high as 91.0 mAh g⁻¹ and a reversible capacity preserved at 77.0 mAh g⁻¹. This result paves a way to novel anti-perovskite family of fluorinated sulfates as potential alkali metal ion solid electrolytes beyond already reported A₃OX (A ​= ​Li or Na, X ​= ​heavy halogen or hydrogenide anions) anti-perovskites.

高电导率固体电解质是开发Na基固态电池的关键组件。然而，仍然缺乏电解质结构原型和相应的合成方法。常规的氧化物和硫化物电解质在烧结合成中消耗前体昂贵（例如Na ₂ S）或能量密集型（例如在1000°C下）。在这里，我们提出了一种新型的富含钙的氟化硫酸盐（Na ₃ SO ₄ F）的抗钙钛矿固体电解质，它通过在适度的温度（500°C）下通过低成本前体的固态反应从Mg和Cl共掺杂中受益。量身定制的双重掺杂使离子电导率提高了三个数量级，接近10 ^-4  s cm ^-1在60°C下 Na空位的产生（通过镁离子掺杂）和晶格扩展（通过用较大尺寸的Cl离子取代F位）是导致电导率提高的原因。基于Na _2.98 Mg _0.01 SO ₄ F _0.95 Cl _0.05电解质的Na–Sn / Fe [Fe（CN）₆ ] ₃固态电池可以可逆运行，其首次放电容量高达91.0 mAh g ^-1，并且具有可逆容量保持在77.0 mAh g ^-1。该结果为潜在的碱金属离子固体电解质提供了一种新的抗钙钛矿型氟化硫酸盐的方法，该电解质已超出已报道的A _3。OX（A = Li或Na，X =重卤素或氢化物阴离子）抗钙钛矿。