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KR-20260062845-A - SULFIDE SOLID ELECTROLYTE, AND ALL-SOLID STATE SECONDARY BATTERY COMPRISING THE SAME

KR20260062845AKR 20260062845 AKR20260062845 AKR 20260062845AKR-20260062845-A

Abstract

The present disclosure relates to a sulfide-based solid electrolyte and an all-solid-state battery comprising the same. According to one aspect, the sulfide-based solid electrolyte comprises an argyrodite-type crystal structure doped with a cation dopant, wherein the cation dopant can reduce the reactivity between H₂O molecules, O₂ molecules, or intermediates derived from said molecules and sulfur contained within said crystal structure.

Inventors

  • 고정현
  • 박정현
  • 한병찬
  • 현수성

Assignees

  • 에스케이온 주식회사
  • 연세대학교 산학협력단

Dates

Publication Date
20260507
Application Date
20251021
Priority Date
20241029

Claims (18)

  1. It includes an argyrodite-type crystal structure doped with a cation dopant, and The above-mentioned cation dopant is, A sulfide-based solid electrolyte that reduces the reactivity between H₂O molecules, O₂ molecules, or intermediates derived from said molecules and sulfur contained within said crystal structure.
  2. In Article 1, The above-mentioned cation dopant is, A sulfide-based solid electrolyte that deactivates at least some of the non-bonding orbitals of the above sulfur.
  3. In Paragraph 2, A sulfide-based solid electrolyte in which the non-bonding orbitals of the sulfur and the d-orbitals of the cation dopant are hybridized by the above doping.
  4. In Article 1, The above-mentioned cation dopant is, A sulfide-based solid electrolyte that induces the formation of chemical bonds between at least some of the adjacent sulfurs within the above crystal structure.
  5. In Paragraph 4, A sulfide-based solid electrolyte that shifts the positions of at least some of the sulfur atoms within the crystal structure by the above doping.
  6. It includes an argyrodite-type crystal structure doped with a cation dopant, and The above-mentioned cation dopant is, A sulfide-based solid electrolyte that is a cation of at least one of a transition metal element and a Group 15 element.
  7. In Paragraph 6, The cations of the above transition metal elements are, Sulfide-based solid electrolyte with an oxidation number of 5 or higher.
  8. In Article 7, The above-mentioned cation dopant is, A sulfide-based solid electrolyte selected from at least one of the group consisting of V 5+ , Mo 6+ , and W 6+ .
  9. In Article 7, The above-mentioned cation dopant is, Sulfide-based solid electrolytes of Mo 6+ or W 6+ .
  10. In Paragraph 6, The cations of the above Group 15 elements are, Sulfide-based solid electrolyte having an ionic radius of 0.2 Å or more.
  11. In Article 10, The above-mentioned cation dopant is, A sulfide-based solid electrolyte selected from at least one of the group consisting of As 5+ , Sb 5+ , and Bi 5+ .
  12. In Article 10, The cations of the above Group 15 elements are, Sulfide-based solid electrolyte having an ionic radius greater than 0.51 Å.
  13. In Paragraph 12, The above-mentioned cation dopant is, Bi 5+ sulfide-based solid electrolyte.
  14. In Paragraph 6, Sulfide-based solid electrolyte comprising a composition represented by the following chemical formula 1: [Chemical Formula 1] Li 6-x P 1-x M 1 x S 5 X In the above chemical formula 1, M1 is Mo or W, X is at least one selected from the group consisting of F, Cl, Br, I and pseudohalogen, and 0.05 ≤ x ≤ 0.5.
  15. In Paragraph 6, Sulfide-based solid electrolyte comprising a composition represented by the following chemical formula 2: [Chemical Formula 2] Li 6 P 1-x M 2 x S 5 X In the above chemical formula 2, M 2 is at least one selected from the group consisting of V, As, Sb and Bi, X is at least one selected from the group consisting of F, Cl, Br, I and pseudohalogen, and 0.05 ≤ x ≤ 0.5.
  16. In Paragraph 14, The sulfide-based solid electrolyte of the above chemical formula 1 is, A sulfide-based solid electrolyte selected from the group consisting of Li 5.95 P 0.95 Mo 0.05 S 5 Cl, Li 5.9 P 0.9 Mo 0.1 S 5 Cl , Li 5.8 P 0.8 Mo 0.2 S 5 Cl, Li 5.5 P 0.5 Mo 0.5 S 5 Cl, Li 5.95 P 0.95 W 0.05 S 5 Cl, Li 5.9 P 0.9 W 0.1 S 5 Cl, Li 5.8 P 0.8 W 0.2 S 5 Cl, and Li 5.5 P 0.5 W 0.5 S 5 Cl.
  17. In Paragraph 15, The sulfide-based solid electrolyte of the above chemical formula 2 is, A sulfide-based solid electrolyte selected from at least one of the group consisting of Li 6 P 0.95 Bi 0.05 S 5 Cl, Li 6 P 0.9 Bi 0.1 S 5 Cl, Li 6 P 0.8 Bi 0.2 S 5 Cl, and Li 6 P 0.5 Bi 0.5 S 5 Cl.
  18. anode; cathode; and An all-solid-state battery comprising a sulfide-based solid electrolyte according to any one of claims 1 to 17.

Description

Sulfide-based solid electrolyte and all-solid-state battery comprising the same The present disclosure relates to a sulfide-based solid electrolyte and an all-solid-state battery comprising the same. Lithium-ion batteries (LIBs) play a crucial role as power and energy storage systems. As demands and expectations for LIB performance continue to rise, operating conditions are approaching safety limits, leading to frequent explosive flame accidents. The cause of these problems lies primarily in commercial organic liquid electrolytes (OLEs). To overcome this, research is continuously being conducted to develop oxide, sulfide, and halide type solid-state electrolytes (SEs) as alternatives to OLEs. Sulfide-framework SEs are attracting attention, particularly due to their high ionic conductivity comparable to that of commercial OLEs. Additionally, because the electronegativity of the S²⁻ anion is lower than that of O²⁻ , sulfide SEs can facilitate the diffusion of lithium ions within the framework. For example, glassy materials such as Li₂SP₂S₅ , Li₁₀GeP₂S₁₂ , and Li₆Azirodite ( Li₆PS₅Cl , hereinafter referred to as LPSCl in this specification) have demonstrated superior ionic conductivity compared to oxides and halides. Furthermore , Li₆Azirodite materials have been reported to exhibit even higher ionic conductivity than that of commercial OLEs (approximately 10 mS/cm) depending on their composition (e.g., Li₅₀Si₁.7₀P₁.4₀S₁₀Cl₁₀ (25 mS / cm), Li₅₀PS₁₀Cl₁₀ (12 mS / cm) , etc. ). Despite their superior performance, the biggest problem with sulfide SEs—the extremely low stability in moist environments—remains unresolved. Sulfide SEs are known to react with H₂O in the air to produce toxic H₂S gas, which can also lead to the decomposition of the sulfide framework and a decrease in ionic conductivity. Figure 1 shows the structure of anion-mixed lithium-argyrodite (LPSCl), (a) is a schematic of the structure of lithium-argyrodite mixed with 50% S-Cl, (b) is the change in DFT energy according to the degree of S-Cl mixing, and (c) is the radius distribution function (RDF) curve of Li and Cl, where the black line represents unmixed argyrodite and the red line represents 50% anion-mixed lithium-argyrodite. The data were obtained through AIMD simulation under conditions of a temperature of 800K. Figure 2(a) is a schematic diagram showing the reaction steps of H₂S generation by H₂O on the surface of LPSCl(001), and (b) is its Gibbs free energy diagram. Figure 3 (a) is a diagram showing the oxygen adsorption before (left) and after (right) on the surface of LPSCl (001), and (b) is the projected density of state (PDOS). Figure 4 (a) is a schematic diagram showing the reaction steps of H₂S generation from H₂O on the surface of LPSCl(001) where pre-adsorbed oxygen is present, and (b) is the Gibbs free energy of the LPSCl(001) plane (top) and the LPSCl(001) plane (bottom) where pre-adsorbed oxygen is present, respectively. Figure 5(a) is the Gibbs free energy diagram of the H₂S generation reaction on the surface of V-, Mo-, and W-doped LPSCl(001), where the solid and dashed horizontal lines represent the reactions in which MS₃O tetrahedra (M: P, V, Mo, and W) are formed and in which they are not formed, respectively. (b) is the Projected density of states (PDOS) for sulfur atoms bonded to the central metal (in order from top to bottom: P, V, Mo, W), and (c) is its Crystal orbital Hamilton pollution (COHP) plot, where E₀f represents the Fermi level of each system. Figure 6(a) is the Gibbs free energy diagram of the H₂S generation reaction on the surface of As-, Sb-, and Bi-doped LPSCl(001), where the solid and dashed horizontal lines represent the reactions in which MS₃O tetrahedra (M: P, V, Mo, and W) are formed and in which they are not formed, respectively. (b) is the Projected density of states (PDOS) for sulfur atoms bonded to the central metals (in order from top to bottom: P, As, and Sb), and (c) is its Crystal orbital Hamilton pollution (COHP) plot, where E₀f represents the Fermi level of each system. Figure 7(a) is a figure showing the formation of SS bonds by Bi doping and the resulting difference in charge density within the LPSCl(001) structure, and (b) is a graph showing the distribution of sulfur-sulfur bonds in the LPSCl(001) structure after cation doping (M: P 5+ , As 5+ , Sb 5+ , and Bi 5+ ), and the cutoff radius for calculating the SS bonds was 5 Å. Figure 8 is a schematic diagram of the unmixed lithium-azirodite bulk structure. Figure 9 shows the average distance (d Li-Cl ) between lithium and chloride ions within an unmixed bulk agyrodite structure in AIMD simulations under 800K temperature conditions. The dashed line represents the initial Li-Cl bond length before performing AIMD simulations. Figure 10 is a graph showing the surface energy of a 50% S-Cl anion-mixed LPSCl surface at different Miller indices. Green and beige represent the surface energy values when surface symmetry is considered and when it is n