401. Structures and conductivities of stable and metastable Li 5 GaS 4 solid electrolytes.
- Author
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Kimura T, Hotehama C, Sakuda A, Tatsumisago M, and Hayashi A
- Abstract
Understanding the differences in the structures and defects in the stable crystalline phase and metastable phase is important for increasing the ionic conductivities of a solid electrolyte. The metastable phase often has higher conductivity than the stable phase. In this study, metastable lithium thiogallate, Li
5 GaS4 , was synthesized via mechanochemistry and stable Li5 GaS4 was obtained by heating the metastable phase. The metastable Li5 GaS4 sample was found to have an antifluorite-type crystal structure with cationic disorder, while the stable phase was found to have a monoclinic crystal structure, similar to that of another solid electrolyte, Li5 AlS4 . In both the structures, the Ga3+ cations were surrounded by four S2- anions in tetrahedral coordination. The conductivity of the metastable phase was determined to be 2.1 × 10-5 S cm-1 at 25 °C, which is 1000 times greater than that of the monoclinic phase. The high conductivity of the metastable phase was achieved owing to cation disorder in the crystal structure., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)- Published
- 2021
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