Observation of Liquid Phase Synthesis of Sulfide Solid Electrolytes Using Time‐Resolved Pair Distribution Function Analysis

Abstract

Time‐resolved pair distribution function (PDF) analysis is performed to clarify the formation mechanism of Li3PS4 sulfide solid electrolytes in liquid phase synthesis with acetonitrile (AN), tetrahydrofuran (THF), and ethyl acetate (EA) solvents. This aims to clarify the relationship between their formations and lithium ionic conductivity. A complex is formed between the precursor of the sulfide solid electrolyte and each solvent during the liquid phase synthesis. The ratio of the solvent to the electrolyte is 3.03 in THF solution. The formation speed of precursors of sulfide solid electrolytes increases in the order AN < THF < EA solution, which is the same order as the lithium ionic conductivity. Thus, the correlation between the ionic conductivity and the formation rate of the precursor of the sulfide solid electrolyte might be related to the stability of the complex formed between Li3PS4 and the solvent during liquid phase synthesis.

Determination of Reaction Enthalpies of Synthesizing β-Li3PS4 in Tetrahydrofuran

“…By heating at 140 °C under vacuum, β-Li 3 PS 4 is obtained. While the synthesis is already examined regarding the obtained particle size, crystallization temperature and duration, , different solvents, ,− and reaction mechanism, − there are no reports on thermal parameters.…”

Evaluation of Various Solvents for the Wet-Chemical Synthesis of β-Li3PS4 under Energy and Environmental Aspects

“…The blue graph represents the diffractogram of intermediate Li 3 PS 4 ·EA, which shows a very intense reflection at around 9.7° 2θ. This reflection has not been described in the literature so far, as the results of the first intermediate in the synthesis using EA have only been shown starting from 10° 2θ , or have not been reported. ,, Comparing the diffractogram of the intermediate Li 3 PS 4 ·EA to the diffractogram of Li 3 PS 4 ·2THF described previously, similarities are visible. Both diffractograms show a very intense reflection at small angles (EA: 9.7° 2θ; THF: 8.4° 2θ) and some other smaller reflections.…”

Solid‐State Electrolytes in Lithium–Sulfur Batteries: Latest Progresses and Prospects

“…For instance, Liu et al [213] applied THF as the solvent to prepare β-Li 3 PS 4 with an ionic conductivity of 0.16 mS cm −1 . Apart from THF, other solvents, such as acetonitrile, [214] DME, [215,216] MeOH [217] and ethyl acetate, [218,219] also have been used in liquid-phase synthesis method. However, the ionic conductivity of electrolytes prepared by liquid-phase synthesis method is usually lower than that prepared by other methods, caused by the impurity and amorphous phases formed at the grain boundaries of the solid electrolyte during the preparation process.…”