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CN-122025765-A - Sulfide solid electrolyte, preparation method and battery

CN122025765ACN 122025765 ACN122025765 ACN 122025765ACN-122025765-A

Abstract

The application discloses a sulfide solid electrolyte, a preparation method and a battery, wherein the chemical formula of the sulfide solid electrolyte is Li 5.5‑2a+ 2b X a P 1‑b Y b S 4.5 Cl 1.5‑c Z c , the chemical formula meets the chemical balance, a, b and c are not 0, X is a transition metal element, Y is a rare earth metal element, and Z is a halogen element except chlorine. The X element can reduce Li + migration barrier and improve ion conductivity, the Y element can improve lithium dendrite puncture resistance and interface stability of the electrolyte, the air stability of the electrolyte can be improved by forming bond energy stronger than P-S bond with the S element, and the Z element can generate a stable LiX layer at the interface between the electrolyte and lithium metal to improve the interface stability between the electrolyte and lithium metal. By introducing X, Y and Z elements, the sulfide solid electrolyte provided by the application has the advantages of high ionic conductivity, excellent air stability and good interface stability.

Inventors

  • Zhao Miaoyi
  • LI YUEYI
  • CHEN GE
  • LIU YANG
  • XIA JUNCHENG
  • JIANG ANQI

Assignees

  • 天齐锂业新能源技术研究(眉山)有限公司

Dates

Publication Date
20260512
Application Date
20260318

Claims (10)

  1. 1. A sulfide solid electrolyte is characterized in that the chemical formula is Li 5.5-2a+2b X a P 1-b Y b S 4.5 Cl 1.5-c Z c , the chemical formula meets the chemical balance, a, b and c are not 0, X is a transition metal element, Y is a rare earth metal element, and Z is a halogen element except chlorine.
  2. 2. The sulfide electrolyte as claimed in claim 1, wherein 0.01≤a≤0.2; And/or b is more than or equal to 0.01 and less than or equal to 0.16; and/or the number of the groups of groups, c is more than or equal to 0.2 and less than or equal to 1.
  3. 3. The sulfide solid state electrolyte of claim 1, wherein X is selected from at least one of Fe, cu, and Zn; and/or Y is selected from at least one of La, ce, nd and Yb; And/or Z is selected from at least one of F, br and I.
  4. 4. A method for producing a sulfide solid state electrolyte as claimed in any one of claims 1 to 3, comprising heat-treating a precursor powder comprising a lithium source, a phosphorus source, a sulfur source, a chlorine source and a doping element source, the doping element including X, Y and Z, to obtain the sulfide solid state electrolyte.
  5. 5. The method for producing a sulfide solid state electrolyte according to claim 4, wherein the heat treatment is performed at a temperature of 450 to 550 ℃ for a holding time of 4 to 20 hours.
  6. 6. The method for producing a sulfide solid state electrolyte as claimed in claim 4, wherein the heating rate of the heat treatment is 1 to 5 ℃.
  7. 7. The method for producing a sulfide solid state electrolyte as claimed in claim 4, wherein the heat treatment is performed in a sealed vacuum environment.
  8. 8. The method for producing a sulfide solid state electrolyte according to claim 4, wherein the precursor powder is produced by mixing a lithium source, a phosphorus source, a sulfur source, a chlorine source and a dopant element source in a pulverizer for 50s to 200 s.
  9. 9. The method for producing a sulfide solid state electrolyte according to claim 4, wherein the lithium source is selected from at least one of Li 2 S, liCl, liBr, liF and LiI; And/or, a sulfur source is selected from at least one of Li 2 S、P 2 S 5 、FeS、CuS、ZnS、La 2 S 3 、Ce 2 S 3 、Nd 2 S 3 and Yb 2 S 3 ; And/or the phosphorus source is selected from P 2 S 5 ; And/or the chlorine source is selected from LiCl; And/or the doping element source is selected from LiBr, liF, liI, feS, cuS, znS, la 2 S 3 、Ce 2 S 3 、Nd 2 S 3 and several of Yb 2 S 3 .
  10. 10. A battery comprising the sulfide solid state electrolyte of any one of claims 1-3.

Description

Sulfide solid electrolyte, preparation method and battery Technical Field The invention relates to the technical field of all-solid-state lithium secondary battery materials, in particular to sulfide solid-state electrolyte, a preparation method and a battery. Background The sulfide solid electrolyte has higher ionic conductivity (up to 10 -2 S/cm level), the ionic conductivity at room temperature is comparable to that of liquid electrolyte, and meanwhile, the sulfide solid electrolyte also has good mechanical ductility, so that the sulfide solid electrolyte is one of solid electrolyte systems with the most industrial prospect. However, practical applications of sulfide solid state electrolytes still face the following key technical challenges: 1) The air stability is poor. The air conditioner is extremely sensitive to humidity, and is easy to react with moisture in the air to generate toxic H 2 S gas, so that the structure is damaged and the performance is degraded; 2) Poor compatibility with the interface of the lithium metal cathode, and easy occurrence of side reaction in the charge and discharge process, and the formation of an interface passivation layer, which leads to the increase of interface impedance and the growth of lithium dendrite. In view of this, the present invention has been made. Disclosure of Invention The invention aims to provide a sulfide solid electrolyte, a preparation method and a battery, and solves the problems of poor air stability and poor compatibility with an electrode interface of the existing sulfide solid electrolyte. The invention is realized in the following way: In a first aspect, the present invention provides a sulfide solid state electrolyte having a chemical formula of Li 5.5-2a+2bXaP1-bYbS4.5Cl1.5-cZc, wherein the chemical formula satisfies a chemical equilibrium, and wherein a, b, and c are not 0, x is a transition metal element, Y is a rare earth metal element, and Z is a halogen element other than chlorine. In an alternative embodiment, 0.01≤a≤0.2; And/or b is more than or equal to 0.01 and less than or equal to 0.16; and/or the number of the groups of groups, c is more than or equal to 0.2 and less than or equal to 1. In an alternative embodiment, X is selected from at least one of Fe, cu and Zn; and/or Y is selected from at least one of La, ce, nd and Yb; And/or Z is selected from at least one of F, br and I. In a second aspect, the invention provides a method for preparing the sulfide solid state electrolyte according to any one of the previous embodiments, comprising the step of performing heat treatment on precursor powder comprising a lithium source, a phosphorus source, a sulfur source, a chlorine source and a doping element source, so as to obtain the sulfide solid state electrolyte, wherein the doping element comprises X, Y and Z. In an alternative embodiment, the heat treatment is performed at a temperature of 450-550 ℃ for a holding time of 4-20 hours. In an alternative embodiment, the heat treatment has a ramp rate of 1-5 ℃ per minute. In an alternative embodiment, the heat treatment is performed in a sealed vacuum environment. In an alternative embodiment, the precursor powder is prepared by placing a lithium source, a phosphorus source, a sulfur source, a chlorine source, and a doping element source in a pulverizer and mixing for 50s-200s to obtain the precursor powder. In an alternative embodiment, the lithium source is selected from at least one of Li 2 S, liCl, liBr, liF and LiI; And/or, a sulfur source is selected from at least one of Li2S、P2S5、FeS、CuS、ZnS、La2S3、Ce2S3、Nd2S3 and Yb 2S3; And/or the phosphorus source is selected from P 2S5; And/or the chlorine source is selected from LiCl; And/or the doping element source is selected from LiBr, liF, liI, feS, cuS, znS, la 2S3、Ce2S3、Nd2S3 and several of Yb 2S3. In a third aspect, the present invention provides a battery comprising a sulfide solid state electrolyte as in any one of the preceding embodiments. The invention has the following beneficial effects: The sulfide solid electrolyte is doped with X, Y and Z elements, wherein the X element replaces Li sites in LPSC electrolyte, the energy band structure can be optimized, li + migration potential barrier is reduced, ion conductivity is improved, the Y element replaces P sites, free electron distribution in the electrolyte is dynamically adjusted through a unique electronic structure, the electron conductivity is reduced, so that lithium dendrite puncture resistance of the electrolyte is improved, interface stability is improved, in addition, bond energy stronger than P-S bond is formed between the S element and the electrolyte, air stability of the electrolyte is improved, reaction of the electrolyte and moisture in air is inhibited, H 2 S gas is reduced, Z element can generate a stable LiX layer at an interface between the electrolyte and lithium metal, uniform deposition of lithium metal is guided, and interface stability of the electrolyte a