Formation Mechanism of Thiophosphate Anions in the Liquid-Phase Synthesis of Sulfide Solid Electrolytes Using Polar Aprotic Solvents

作者：Marcela Calpa, Nataly Carolina Rosero‐Navarro, Akira Miura, Kota Terai, Futoshi Utsuno, Kiyoharu Tadanaga · 发表于：Chemistry of Materials · 年份：2020 · DOI：10.1021/acs.chemmater.0c03198 · 被引用次数：37 · 研究领域：Advanced Battery Materials and Technologies、Advancements in Battery Materials、Advanced battery technologies research

Preparation of sulfide-based Li-ion conductive solid electrolytes by a liquid-phase process has been proposed as an effective route for industrial scaling-up. However, reaction mechanisms in the liquid-phase synthesis or the role of solvents in the reactions is not yet well understood. Here, the reaction between Li 2 S and P 2 S 5 in the composition of 50:50 mol % mediated by a polar aprotic solvent (acetonitrile) was investigated. The study of the crystal and local structure of the 50Li 2 S·50P 2 S 5 sample revealed large chemical changes upon crystallization, highlighting the initial formation of a polymer-like (PS 3 – ) n intermediate. On the basis of the (PS 3 – ) n intermediate, the reaction pathways for the formation of P 2 S 6 2–, PS 4 3–, and P 2 S 7 4– anions are elucidated. These findings give a deeper insight into the reaction mechanisms governing the liquid-phase synthesis of sulfide solid electrolytes and provide more specific criteria for designing novel materials with superior characteristics through this liquid-phase approach.