skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


Title: 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.  more » « less
Award ID(s):
2219184 1825470
PAR ID:
10423584
Author(s) / Creator(s):
; ;
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
More Like this
  1. ; ; (, Journal of The Electrochemical Society)
    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. 
    more » « less
  2. ; ; ; (, Journal of Materials Chemistry A)
    Amorphous Li 3 PS 4 (LPS) solid-state electrolytes are promising for energy-dense lithium metal batteries. LPS glass, synthesized from a 3 : 1 mol ratio of Li 2 S and P 2 S 5 , has high ionic conductivity and can be synthesized by ball milling or solution processing. Ball milling has been attractive because it provides the easiest route to access amorphous LPS with a conductivity of 3.5 × 10 −4 S cm −1 (20 °C). However, achieving the complete reaction of precursors via ball milling can be difficult, and most literature reports use X-ray diffraction (XRD) or Raman spectroscopy to confirm sample purity, both of which have limitations. Furthermore, the effect of residual precursors on ionic conductivity and lithium metal cycling is unknown. In this work, we illustrate the importance of multimodal characterization to determine LPS phase and chemical purity. To determine the residual Li 2 S content in LPS, we show that (1) XRD and 31 P solid state nuclear magnetic resonance (ssNMR) are insufficient and (2) Raman loses sensitivity at concentrations below 12 mol% Li 2 S. Most importantly, we show that 7 Li ssNMR is highly sensitive. Using 7 Li ssNMR, we investigate the effect of ball milling parameters and develop a robust and highly reproducible procedure for pure LPS synthesis. We find that as the residual Li 2 S precursor content increases, LPS conductivity decreases and lithium metal batteries exhibit higher overpotentials and poor cycle life. Our work reveals the importance of multimodal characterization techniques for amorphous solid-state electrolyte characterization and will enable better synthetic strategies for highly conductive electrolytes for efficient energy-dense solid-state lithium metal batteries. 
    more » « less
  3. ; ; ; ; ; ; ; ; (, Advanced Functional Materials)
    Abstract All‐solid‐state rechargeable sodium (Na)‐ion batteries are promising for inexpensive and high‐energy‐density large‐scale energy storage. In this contribution, new Na solid electrolytes, Na3−yPS4−xClx, are synthesized with a strategic approach, which allows maximum substitution of Cl for S (x= 0.2) without significant compromise of structural integrity or Na deficiency. A maximum conductivity of 1.96 mS cm−1at 25 °C is achieved for Na3.0PS3.8Cl0.2, which is two orders of magnitude higher compared with that of tetragonal Na3PS4(t‐Na3PS4). The activation energy (Ea) is determined to be 0.19 eV. Ab initio molecular dynamics simulations shed light on the merit of maximizing Cl‐doping while maintaining low Na deficiency in enhanced Na‐ion conduction. Solid‐state nuclear magnetic resonance (NMR) characterizations confirm the successful substitution of Cl for S and the resulting change of P oxidation state from 5+ to 4+, which is also verified by spin moment analysis. Ion transport pathways are determined with a tracer‐exchange NMR method. The functional detects that promote Na ‐ion transport are maximized for further improvement in ionic conductivity. Full‐cell performance is demonstrated using Na/Na3.0PS3.8Cl0.2/Na3V2(PO4)3with a reversible capacity of ≈100 mAh g‐1at room temperature. 
    more » « less
  4. ; ; ; ; ; ; ; ; ; ; et al (, Science Advances)
    2LiX-GaF3(X = Cl, Br, I) electrolytes offer favorable features for solid-state batteries: mechanical pliability and high conductivities. However, understanding the origin of fast ion transport in 2LiX-GaF3has been challenging. The ionic conductivity order of 2LiCl-GaF3(3.20 mS/cm) > 2LiBr-GaF3(0.84 mS/cm) > 2LiI-GaF3(0.03 mS/cm) contradicts binary LiCl (10−12S/cm) < LiBr (10−10S/cm) < LiI (10−7S/cm). Using multinuclear7Li,71Ga,19F solid-state nuclear magnetic resonance and density functional theory simulations, we found that Ga(F,X)npolyanions boost Li+-ion transport by weakening Li+-X−interactions via charge clustering. In 2LiBr-GaF3and 2LiI-GaF3, Ga-X coordination is reduced with decreased F participation, compared to 2LiCl-GaF3. These insights will inform electrolyte design based on charge clustering, applicable to various ion conductors. This strategy could prove effective for producing highly conductive multivalent cation conductors such as Ca2+and Mg2+, as charge clustering of carboxylates in proteins is found to decrease their binding to Ca2+and Mg2+. 
    more » « less
  5. ; (, Journal of the American Ceramic Society)
    Abstract In this report, a facile wet chemical method using acetonitrile combined with thermal annealing was used to prepare Li2S‐P2S5(LPS) based glass‐ceramic electrolytes with (1 wt%, 3 wt%, and 5 wt% Ce2S3) and without Ce2S3doping. The crystal structure, ionic conductivity, and chemical stability of Li7P3S11glass‐ceramic electrolytes were examined at varying temperatures (250–350°C). The results indicated that the highest ionic conductivity of 3.15 × 10−4S cm−1for pure Li7P3S11was observed at a temperature of 325°C. By incorporating 1 wt% Ce2S3and subjecting it to a heat treatment at 250°C, the glass ceramic electrolyte attained a remarkable ionic conductivity of 7.7 × 10−4(S cm−1) at 25°C. Furthermore, it exhibited a stable and extensive electrochemical potential range, reaching up to 5 volts when compared to the Li/Li+reference electrode. By tuning the glass transition and crystallization temperature, cerium doping seems to make Li7P3S11more chemically stable, compared to its original 70Li2S‐30P2S5counterpart. According to Raman and X‐ray photoelectron spectroscopy analyses, cerium doping inhibits the decomposition of highly conductive P2S74‐(pyro‐thiophosphate) to PS43−and P2S64−. Doped LPS has a greater crystallinity and more uniform microstructure than pure LPS, according to XRD, Raman spectroscopy, and scanning electron microscopy analysis. Consequently, Li7P2.9Ce0.1S11electrolyte shows great potential as a solid‐state electrolyte for constructing high‐performance sulfide‐based all‐solid‐state batteries. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email