Sodium thioantimonate (Na 3 SbS 4 ) is an attractive solid-state electrolyte for sodium-ion batteries due to its high ionic conductivity and stability in protic solvents. Herein, we describe solution-based routes for its synthesis. First, we demonstrate the synthesis of the Sb 2 S 3 precursor via thermodynamically favorable metathesis between Na 2 S and SbCl 3 . This solution-based approach is further extended to couple the resulting Sb 2 S 3 with Na 2 S for the synthesis of Na 3 SbS 4 . It is shown that ethanol is a superior solvent to water for solution-based synthesis of Na 3 SbS 4 with respect to yield, morphology, and performance. Amorphous Sb 2 S 3 synthesized from low-temperature metathesis produced highly crystalline Na 3 SbS 4 with a room temperature Na + conductivity of 0.52 mS cm −1 and low activation energy, comparable to leading values reported in the literature.
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Synthesis of high-purity Li 2 S nanocrystals via metathesis for solid-state electrolyte applications
Li 2 S is the key precursor for synthesizing thio-LISICON electrolytes employed in solid state batteries. However, conventional synthesis techniques such as carbothermal reduction of Li 2 SO 4 aren't suitable for the generation of low-cost, high-purity Li 2 S. Metathesis, in which LiCl is reacted with Na 2 S in ethanol, is a scalable synthesis method conducted at ambient conditions. The NaCl byproduct is separated from the resulting Li 2 S solution, and the solvent is removed by evaporation and thermal annealing. However, the annealing process reveals the presence of oxygenated impurities in metathesis Li 2 S that are not usually observed when recovering Li 2 S from ethanol. In this work we investigate the underlying mechanism of impurity formation, finding that they likely derive from the decomposition of alkoxide species that originate from the alcoholysis of the Na 2 S reagent. With this mechanism in mind, several strategies to improve Li 2 S purity are explored. In particular, drying the metathesis Li 2 S under H 2 S at low temperature was most effective, resulting in high-purity Li 2 S while retaining a beneficial nanocrystal morphology (∼10 nm). Argyrodite electrolytes synthesized from this material exhibited essentially identical phase purity, ionic conductivity (3.1 mS cm −1 ), activation energy (0.19 eV), and electronic conductivity (6.4 × 10 −6 mS cm −1 ) as that synthesized from commercially available battery-grade Li 2 S.
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- NSF-PAR ID:
- 10423584
- Date Published:
- Journal Name:
- Journal of Materials Chemistry A
- Volume:
- 11
- Issue:
- 14
- ISSN:
- 2050-7488
- Page Range / eLocation ID:
- 7652 to 7661
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/D3TA00076A
