Phase formation through synthetic control: polymorphism in the sodium-ion solid electrolyte Na4P2S6

Scholz, Tanja; Schneider, Christian; Eger, Roland; Düppel, Viola; Moudrakovski, Igor L.; Schulz, Armin; Nuß, Jürgen; Lotsch, Bettina V.

doi:10.1039/d0ta11008f

Cited by 11 publications

(27 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The latter anneals above 500 °C to a product very similar to the solid-state material. The structural differences are discussed in detail in ref ( 11 ). The β → γ phase transition is not affected by the Na 4 P 2 S 6 synthesis.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…Variable-temperature powder X-ray diffraction (PXRD) experiments were performed on Na 4 P 2 S 6 well above the α–β phase transition at 160 °C. 11 A new set of Bragg peaks is observed to emerge at 580 °C, as shown in Figure 1 . The diffraction peaks of β-Na 4 P 2 S 6 and the new crystalline phase coexist up to 585 °C (measured every 5 K), at which point the β phase disappears.…”

mentioning

confidence: 91%

“…The α → β phase transition involves very small atomic rearrangements and shows a correspondingly small latent heat of ∼8.7 J/g. 11 In contrast, the β → γ transition has a latent heat corresponding to about half that of the melting transition (∼60 versus ∼90–120 J/g). This implies that substantial structural rearrangements are now required to form the γ phase.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Superionic Conduction in the Plastic Crystal Polymorph of Na₄P₂S₆

et al. 2022

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Section: Experimental Methodsmentioning

confidence: 99%

mentioning

confidence: 91%

mentioning

confidence: 99%

See 1 more Smart Citation

Superionic Conduction in the Plastic Crystal Polymorph of Na₄P₂S₆

et al. 2022

Self Cite

View full text Add to dashboard Cite

show abstract

“…33 Furthermore, Na 4 P 2 S 6 is a Na-ion solid electrolyte where stacking faults generated from a precipitation synthesis stabilize a conductive high temperature phase at room temperature. 34 A number of other relevant examples also exist in Li-and Na-ion transition metal oxide cathodes, 35−48 Ag nanoparticle catalysts, 49 and ionic conductors. 50,51 The three-dimensional LYC crystal structure (space group P3̅ m1) investigated in this study bears a strong resemblance to the layered structure of YCl 3 (space group C2/m), where both structures exhibit a hexagonal close-packed Cl − anion sublattice (ABAB) and a hexagonal Y 3+ arrangement.…”

Section: Introductionmentioning

confidence: 99%

Stacking Faults Assist Lithium-Ion Conduction in a Halide-Based Superionic Conductor

et al. 2022

View full text Add to dashboard Cite

In the pursuit of urgently needed, energy dense solid-state batteries for electric vehicle and portable electronics applications, halide solid electrolytes offer a promising path forward with exceptional compatibility against high-voltage oxide electrodes, tunable ionic conductivities, and facile processing. For this family of compounds, synthesis protocols strongly affect cation site disorder and modulate Li + mobility. In this work, we reveal the presence of a high concentration of stacking faults in the superionic conductor Li 3 YCl 6 and demonstrate a method of controlling its Li + conductivity by tuning the defect concentration with synthesis and heat treatments at select temperatures. Leveraging complementary insights from variable temperature synchrotron X-ray diffraction, neutron diffraction, cryogenic transmission electron microscopy, solid-state nuclear magnetic resonance, density functional theory, and electrochemical impedance spectroscopy, we identify the nature of planar defects and the role of nonstoichiometry in lowering Li + migration barriers and increasing Li site connectivity in mechanochemically synthesized Li 3 YCl 6 . We harness paramagnetic relaxation enhancement to enable 89 Y solid-state NMR and directly contrast the Y cation site disorder resulting from different preparation methods, demonstrating a potent tool for other researchers studying Y-containing compositions. With heat treatments at temperatures as low as 333 K (60 °C), we decrease the concentration of planar defects, demonstrating a simple method for tuning the Li + conductivity. Findings from this work are expected to be generalizable to other halide solid electrolyte candidates and provide an improved understanding of defect-enabled Li + conduction in this class of Li-ion conductors.

show abstract

“…33 Furthermore, Na 4 P 2 S 6 is a Na-ion solid electrolyte where stacking faults generated from a precipitation synthesis stabilize a conductive high temperature phase at room temperature. 34 A number of other relevant examples also exist in Li-and Na-ion transition metal oxide cathodes, [35][36][37][38][39][40][41][42][43][44][45][46][47][48] Ag nanoparticle catalysts, 49 and ionic conductors. 50,51 The three-dimensional LYC crystal structure (space group: P 3m1) investigated in this study bears a strong resemblance to the layered structure of YCl 3 (space group: C2/m), where both structures exhibit a hexagonal close-packed Clanion sublattice (ABAB) and a hexagonal Y 3+ arrangement.…”

Section: Introductionmentioning

confidence: 99%

Stacking Faults Assist Lithium-Ion Conduction in a Halide-Based Superionic Conductor

Sebti,

Evans,

Chen

et al. 2022

Preprint

View full text Add to dashboard Cite

In the pursuit of urgently-needed, energy dense solid-state batteries for electric vehicle and portable electronics applications, halide solid electrolytes offer a promising path forward with exceptional compatibility against high-voltage oxide electrodes, tunable ionic conductivities, and facile processing. For this family of compounds, synthesis protocols strongly affect cation site disorder and modulate Li + mobility. In this work, we reveal the presence of a high concentration of stacking faults in the superionic conductor Li 3 YCl 6 and demonstrate a method of controlling its Li + conductivity by tuning the defect concentration with synthesis and heat treatments at select temperatures. Leveraging complementary insights from variable temperature synchrotron X-ray diffraction, neutron diffraction, cryogenic transmission electron microscopy, solid-state nuclear magnetic resonance, density functional theory, and electrochemical impedance spectroscopy, we identify the nature of planar defects and the role of nonstoichiometry in lowering Li + migration barriers and increasing Li site connectivity in mechanochemically-synthesized Li 3 YCl 6 . We harness paramagnetic relaxation enhancement to enable 89 Y solid-state NMR, and directly contrast the Y cation site disorder resulting from different preparation methods, demonstrating a potent tool for other researchers studying Y-containing compositions. With heat treatments at temperatures as low as 333 K (60°C), we decrease the concentration of planar defects, demonstrating a simple method for tuning the Li + conductivity. Findings from this work are expected to be generalizable to other halide solid electrolyte candidates and provide an improved understanding of defectenabled Li + conduction in this class of Li-ion conductors.the combustible organic LE with a nonflammable SE severely lessens the consequences of an internal short-circuit and may also extend the range of operating temperatures for the cell. 1,2 Beyond safety, the lack of any liquid component opens the door to bipolar stack SSB architectures that enhance battery module energy density and lower manufacturing costs as cells no longer have to be individually packed to avoid leakage. 3,4 Notably, Li-ion SEs have transference numbers close to one which could allow for faster charging than LE cells when paired with high ionic conductivities. 1,[5][6][7][8][9] Since a 2018 publication from Asano et al. 10 reported high Li + conductivities in Li 3 YCl 6 (LYC) and Li 3 YBr 6 (LYB), lithium-containing halide ternaries have emerged as appealing SE candidates owing to their promising room temperature conductivities, strong oxidative stability to high potentials, and hence compatibility with oxide-based cathode materials. 10,11 Sulfide SEs rely on a body-centered cubic (BCC) anion sublattice to ensure low migration barriers and fast Li + conduction. 12-14 Oxides require aliovalent doping to achieve appreciable Li + conduction through concerted migration, enabled by greater Li + concentrations and concomitant occupatio...

show abstract

Phase formation through synthetic control: polymorphism in the sodium-ion solid electrolyte Na₄P₂S₆

Abstract: The development of all-solid-state sodium batteries for scalable energy storage solutions requires fast sodium conducting solid electrolytes. To fast-track their discovery, candidate materials need to be identified that are synthesized...

Cited by 11 publications

References 35 publications

Superionic Conduction in the Plastic Crystal Polymorph of Na₄P₂S₆

Superionic Conduction in the Plastic Crystal Polymorph of Na₄P₂S₆

Stacking Faults Assist Lithium-Ion Conduction in a Halide-Based Superionic Conductor

Stacking Faults Assist Lithium-Ion Conduction in a Halide-Based Superionic Conductor

Contact Info

Product

Resources

About

Phase formation through synthetic control: polymorphism in the sodium-ion solid electrolyte Na4P2S6

Abstract: The development of all-solid-state sodium batteries for scalable energy storage solutions requires fast sodium conducting solid electrolytes. To fast-track their discovery, candidate materials need to be identified that are synthesized...

Cited by 11 publications

References 35 publications

Superionic Conduction in the Plastic Crystal Polymorph of Na4P2S6

Superionic Conduction in the Plastic Crystal Polymorph of Na4P2S6

Stacking Faults Assist Lithium-Ion Conduction in a Halide-Based Superionic Conductor

Stacking Faults Assist Lithium-Ion Conduction in a Halide-Based Superionic Conductor

Contact Info

Product

Resources

About

Phase formation through synthetic control: polymorphism in the sodium-ion solid electrolyte Na₄P₂S₆

Superionic Conduction in the Plastic Crystal Polymorph of Na₄P₂S₆

Superionic Conduction in the Plastic Crystal Polymorph of Na₄P₂S₆