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CN-122000441-A - Solid electrolyte Li4SnS4And a method for preparing the same

CN122000441ACN 122000441 ACN122000441 ACN 122000441ACN-122000441-A

Abstract

The invention relates to a solid electrolyte Li 4 SnS 4 and a preparation method thereof, wherein an XRD spectrum of the solid electrolyte Li 4 SnS 4 comprises a first characteristic peak and a second characteristic peak, the first characteristic peak is positioned at 2θ=17 degrees+/-0.5 degrees, the peak height is I 1 , the peak area is S 1 , the second characteristic peak is positioned at 2θ=25.9 degrees+/-0.5 degrees, the peak height is I 2 , the peak area is S 2 , the I 1 /I 2 <0.86,S 1 /S 2 is more than 0.7, and the ion conductivity of the solid electrolyte Li 4 SnS 4 is more than 6.5x10 ‑5 S/cm. The preparation method provided by the invention can obviously improve the ionic conductivity of Li 4 SnS 4 while ensuring the synthesis efficiency.

Inventors

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Assignees

  • 瑞固(衢州)新材料科技有限公司

Dates

Publication Date
20260508
Application Date
20260203

Claims (10)

  1. 1. A solid electrolyte Li 4 SnS 4 , characterized in that the XRD spectrum of the solid electrolyte Li 4 SnS 4 comprises a first characteristic peak and a second characteristic peak; The first characteristic peak is positioned at 2θ=17° ±0.5°, the peak height is I 1 , and the peak area is S 1 ; The second characteristic peak is positioned at2θ=25.9° ±0.5°, the peak height is I 2 , and the peak area is S 2 ; And 0.64< I 1 /I 2 <0.86,S 1 /S 2 >0.7; The ionic conductivity of the solid electrolyte Li 4 SnS 4 is 6.5X10- -5 S/cm or more.
  2. 2. The solid electrolyte Li 4 SnS 4 of claim 1, wherein the half-width of the first characteristic peak is >0.6.
  3. 3. The solid electrolyte Li 4 SnS 4 of claim 1, wherein the spatial group of solid electrolyte Li 4 SnS 4 comprises Pnma and/or P63/mmc; And/or, the S 1 >0.144.
  4. 4. A method for producing a solid electrolyte Li 4 SnS 4 , characterized by comprising the steps of: Mixing Li 2 S, sn with S to obtain raw material powder, heating the raw material powder and a solvent under a sealed environment condition, and vacuum drying after the reaction is finished to obtain precursor powder, wherein the precursor powder is calcined in a protective atmosphere to obtain the solid electrolyte Li 4 SnS 4 in any one of claims 1-3.
  5. 5. The method according to claim 4, wherein the temperature of the temperature-raising reaction is 100 ℃ to 200 ℃.
  6. 6. The method according to claim 4 or 5, wherein the temperature-raising reaction time is 1h to 5h.
  7. 7. The method according to any one of claims 4 to 6, wherein the solvent comprises water; And/or the mass-volume ratio of the raw material powder to the solvent is 1g/20 mL-1 g/30mL.
  8. 8. The method according to any one of claims 4 to 7, wherein the vacuum drying temperature is 140 ℃ to 160 ℃; and/or the vacuum drying time is 1-5 h.
  9. 9. The method according to any one of claims 4 to 8, wherein the calcination temperature is 240 ℃ to 280 ℃; and/or the calcination time is 0.5 h-1.5 h.
  10. 10. The preparation method according to claim 4, characterized in that the preparation method comprises the steps of: (1) Mixing Li 2 S, sn with S to obtain raw material powder; (2) Mixing raw material powder and a solvent, carrying out a heating reaction at 100-200 ℃ for 1-5 h under a sealed environment condition, and carrying out vacuum drying at 140-160 ℃ for 1-5 h after the reaction is finished to obtain precursor powder; The solvent comprises water, and the mass volume ratio of the raw material powder to the solvent is 1g/20 mL-1 g/30mL; (3) And calcining the precursor powder at 240-280 ℃ for 0.5-1.5 h in an argon atmosphere to obtain the solid electrolyte Li 4 SnS 4 .

Description

Solid electrolyte Li 4SnS4 and preparation method thereof Technical Field The invention belongs to the technical field of solid electrolyte, and relates to solid electrolyte Li 4SnS4 and a preparation method thereof. Background The solid electrolyte is a core component of the next generation of high-safety lithium sulfur batteries, wherein Li 4SnS4 is one of research hotspots in the field due to good ion conduction potential and chemical stability. Currently, in the prior art, a main scheme for preparing a Li 4SnS4 solid electrolyte is to take lithium sulfide (Li 2 S) and tin disulfide (SnS 2) as raw materials, and synthesize a target product through a specific reaction path. However, the existing preparation methods using Li 2 S and SnS 2 as raw materials have limitations in the balance of reaction efficiency and product performance. Although some schemes can synthesize Li 4SnS4, the ionic conductivity of the obtained solid electrolyte is often difficult to meet the actual application requirements of high-performance batteries due to the limitations of the reactivity and the reaction conditions of raw materials, and the industrialization process of the solid electrolyte is restricted. Meanwhile, the control of the reaction temperature in the prior art is mostly biased to a middle-low temperature zone, and the improvement effect of the high-temperature condition on the reaction sufficiency of the raw materials is not fully utilized. How to remarkably improve the ionic conductivity of Li 4SnS4 while ensuring the synthesis efficiency by optimizing the raw material combination and the reaction temperature becomes a problem to be solved in the current Li 4SnS4 solid electrolyte preparation field. Disclosure of Invention Aiming at the defects existing in the prior art, the invention aims to provide the solid electrolyte Li 4SnS4 and the preparation method thereof, and the preparation method provided by the invention can obviously improve the ionic conductivity of Li 4SnS4 while ensuring the synthesis efficiency. In order to achieve the aim of the invention, the invention adopts the following technical scheme: In a first aspect, the present invention provides a solid electrolyte Li 4SnS4, the XRD spectrum of the solid electrolyte Li 4SnS4 comprising a first characteristic peak and a second characteristic peak; The first characteristic peak is positioned at 2θ=17° ±0.5°, the peak height is I 1, and the peak area is S 1; The second characteristic peak is positioned at2θ=25.9° ±0.5°, the peak height is I 2, and the peak area is S 2; And 0.64< I 1/I2<0.86,S1/S2 >0.7; The ionic conductivity of the solid electrolyte Li 4SnS4 is 6.5X10- -5 S/cm or more. The first characteristic peak and the second characteristic peak of the solid electrolyte Li 4SnS4 provided by the invention have parameter ratios (such as peak height, half-peak width, peak area and the like) which are obviously superior to those of conventional diffraction peaks, so that the solid electrolyte has optimized crystal orientation and high crystallinity. Compared with the possible defects of crystallinity and disordered crystal face orientation in the prior art, the characteristic peak characteristics of the invention show that crystal faces of the solid electrolyte have regular arrangement, thereby reducing the crystal lattice defects and the crystal boundary impedance, ensuring the continuity and smoothness of a Li + transmission channel, reducing the mass transfer resistance and enabling the ion conductivity of the solid electrolyte Li 4SnS4 to reach more than 6.5X10 -5 S/cm. In certain embodiments, the first characteristic peak has a full width at half maximum (FWHM 1) >0.6. In certain embodiments, the spatial group of solid electrolyte Li 4SnS4 includes Pnma and/or P63/mmc. In certain embodiments, the S 1 >0.144. In a second aspect, the present invention provides a method for preparing a solid electrolyte Li 4SnS4, the method comprising the steps of: Mixing Li 2 S, sn with S to obtain raw material powder, heating the raw material powder and a solvent under a sealed environment condition, and vacuum drying after the reaction is finished to obtain precursor powder, wherein the precursor powder is calcined in a protective atmosphere to obtain the solid electrolyte Li 4SnS4 of the first aspect. The ionic conductivity of the solid electrolyte Li 4SnS4 prepared by the method is more than 6.5X10 -5 S/cm, the prior art takes Li 2 S and SnS 2 as raw materials, sn in SnS 2 is +4, a valence conversion path is fixed when the solid electrolyte reacts with Li 2 S, the interfacial reaction activity of the raw materials is limited, lattice defects are easily formed due to insufficient reaction, and Li + transmission is prevented. According to the preparation method, li 2 S, elemental Sn and S are selected as raw materials, the reactivity of elemental components is higher, and under a high-pressure hydrothermal environment, water molecules are used as mass transfer med