Liquid-phase synthesis for solid electrolytes has received considerable attention owing to its shape control, with the potential to produce particles easily on a large scale, and its low cost and energy consumption. However, solid electrolytes prepared through liquid-phase synthesis have been shown to have lower ionic conductivity than solid electrolytes prepared through the mechanical milling method. Recently, following various efforts, our group found that the crystallinity and remaining intermediate are the reasons for the low ionic conductivity of these materials. By using tetrahydrofuran (THF), we successfully improved the ionic conductivity of Li₃PS₄ to 1.85 × 10⁻⁴ S cm⁻¹ at 25 °C, higher than that afforded by ethyl propionate, which was reported to produce the highest ionic conductivity among the solvents used for liquid-phase synthesis. High-energy X-ray diffraction (XRD) measurements coupled with pair distribution function (PDF) analysis were employed to analyze the synthesized materials in order to determine why the ionic conductivity was higher than that of a sample prepared using ethyl propionate. The PDF analysis revealed that the crystallization of Li₃PS₄ can be suppressed using THF, which has a lower boiling point than ethyl propionate. Moreover, it was revealed that the solvent could not be removed completely when the material has an amorphous structure, and thus, the ionic conductivity was lower than that of a material prepared using the solid-phase synthesis method.

用于固体电解质的液相合成由于其形状控制而备受关注，其具有容易大规模生产颗粒的潜力以及其低成本和能耗。然而，已经证明通过液相合成制备的固体电解质比通过机械研磨方法制备的固体电解质具有更低的离子传导率。最近，经过各种努力，我们的小组发现结晶度和残留的中间体是这些材料低离子电导率的原因。通过使用四氢呋喃（THF），我们成功地将Li ₃ PS ₄的离子电导率提高到1.85×10 ^-4  S cm ^-1在25°C时，比丙酸乙酯所提供的要高，据报道丙酸乙酯在液相合成所用的溶剂中产生最高的离子电导率。高能X射线衍射（XRD）测量与成对分布函数（PDF）分析一起用于分析合成材料，以确定为什么离子电导率比使用丙酸乙酯制备的样品高。PDF分析显示Li ₃ PS ₄的结晶可以使用沸点比丙酸乙酯低的四氢呋喃（THF）来抑制这种现象。此外，揭示了当材料具有非晶结构时不能完全除去溶剂，因此，离子电导率低于使用固相合成法制备的材料。