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Superionic Conduction in the Plastic Crystal Polymorph of Na(4)P(2)S(6)

[Image: see text] Sodium thiophosphates are promising materials for large-scale energy storage applications benefiting from high ionic conductivities and the geopolitical abundance of the elements. A representative of this class is Na(4)P(2)S(6), which currently shows two known polymorphs−α and β. T...

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Detalles Bibliográficos
Autores principales: Scholz, Tanja, Schneider, Christian, Terban, Maxwell W., Deng, Zeyu, Eger, Roland, Etter, Martin, Dinnebier, Robert E., Canepa, Pieremanuele, Lotsch, Bettina V.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2022
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9008513/
https://www.ncbi.nlm.nih.gov/pubmed/35434367
http://dx.doi.org/10.1021/acsenergylett.1c02815
Descripción
Sumario:[Image: see text] Sodium thiophosphates are promising materials for large-scale energy storage applications benefiting from high ionic conductivities and the geopolitical abundance of the elements. A representative of this class is Na(4)P(2)S(6), which currently shows two known polymorphs−α and β. This work describes a third polymorph of Na(4)P(2)S(6), γ, that forms above 580 °C, exhibits fast-ion conduction with low activation energy, and is mechanically soft. Based on high-temperature diffraction, pair distribution function analysis, thermal analysis, impedance spectroscopy, and ab initio molecular dynamics calculations, the γ-Na(4)P(2)S(6) phase is identified to be a plastic crystal characterized by dynamic orientational disorder of the P(2)S(6)(4–) anions translationally fixed on a body-centered cubic lattice. The prospect of stabilizing plastic crystals at operating temperatures of solid-state batteries, with benefits from their high ionic conductivities and mechanical properties, could have a strong impact in the field of solid-state battery research.