CN-121983650-A - Solid sulfide electrolyte and preparation method thereof

CN121983650ACN 121983650 ACN121983650 ACN 121983650ACN-121983650-A

Abstract

The application provides a solid sulfide electrolyte and a preparation method thereof. The preparation method of the solid sulfide electrolyte comprises the steps of mixing phosphorus pentasulfide, lithium sulfide and lithium chloride with a first solvent, performing ball milling to obtain a precursor, performing heat treatment on the precursor to obtain precursor powder, performing tabletting treatment on the precursor powder to obtain a flaky precursor, performing sintering on the flaky precursor in an inert protective atmosphere to obtain a sintered product, mixing the sintered product with a second solvent, performing fractional liquid-phase grinding to obtain a fractional grinding end product, and performing heat treatment on the fractional grinding end product to obtain the solid sulfide electrolyte, wherein the step S1 comprises the steps of performing heat treatment on the precursor to obtain the flaky precursor, and performing sintering on the flaky precursor in an inert protective atmosphere to obtain the sintered product, and the step S5 comprises the steps of performing fractional liquid-phase grinding on the sintered product to obtain the fractional grinding end product. In the preparation method of the solid sulfide electrolyte, the particle consistency of the solid sulfide electrolyte product can be improved through the synergistic effect of tabletting treatment and graded liquid phase grinding.

Inventors

ZHAO FENGDONG
XU FANGLIN
GE JIANWEN
YU DA
DING JIANYUN
CHEN JIE

Assignees

奇瑞汽车股份有限公司

Dates

Publication Date: 20260505
Application Date: 20260128

Claims (10)

1. A method of preparing a solid sulfide electrolyte, the method comprising: step S1, mixing phosphorus pentasulfide, lithium sulfide and lithium chloride with a first solvent, and performing ball milling to obtain a precursor; step S2, performing heat treatment on the precursor to obtain precursor powder; Step S3, tabletting the precursor powder to obtain a flaky precursor; Step S4, sintering the flaky precursor under inert protective atmosphere to obtain a sintered product; Step S5, mixing the sintered product with a second solvent and carrying out fractional liquid phase grinding to obtain a fractional grinding end product; And S6, carrying out heat treatment on the graded grinding end product to obtain the solid sulfide electrolyte.
2. The method according to claim 1, wherein in the step S3, the pressure used in the tabletting is 100 to 240mpa, and the time of the tabletting is 2 to 5 minutes.
3. The method for producing a solid sulfide electrolyte according to claim 1 or 2, wherein in the step S5, the classified liquid phase grinding includes a first stage liquid phase grinding, a second stage liquid phase grinding and a third stage liquid phase grinding, Preferably, in the first-stage liquid-phase grinding, zirconia balls with the diameter of 5-7 mm are used, the rotating speed is 250-320 r/min, the grinding time is 1-3 h, and a first-stage grinding product with the D50 of 4-5 mu m is obtained; In the second-stage liquid-phase grinding, zirconia balls with the diameter of 3-5 mm are used, the rotating speed is 180-250 r/min, the grinding time is 1-3 h, and a second-stage grinding product with the D50 of 2-4 mu m is obtained; In the third-stage liquid-phase grinding, zirconia balls with the diameter of 0.1-3 mm are used, the rotating speed is 100-150 r/min, the grinding time is 1-2 h, and the graded grinding end product with the D50 of 0.8-2 mu m is obtained.
4. The method for preparing a solid sulfide electrolyte according to claim 1, wherein the molar ratio of phosphorus pentasulfide, lithium sulfide and lithium chloride is 1 (4.4-5.3): 1.7-2.2.
5. The method for producing a solid sulfide electrolyte according to claim 1, wherein the first solvent and the second solvent are each independently selected from one or more of the group consisting of acetonitrile, petroleum ether, heptane, butyl butyrate, isobutyl isobutyrate, p-xylene, o-xylene, octane, and nonane.
6. The method according to claim 4 or 5, wherein in the step S4, the sintering temperature is in the range of 400 to 600 ℃.
7. The method for producing a solid sulfide electrolyte according to claim 1 or 2, characterized in that in the step S2, the heat treatment temperature is in the range of 60 to 120 ℃.
8. A solid sulfide electrolyte prepared by the method of preparing a solid sulfide electrolyte according to any one of claims 1 to 7.
9. The solid state sulfide electrolyte of claim 8, wherein the difference between D90 and D10 of the solid state sulfide electrolyte is in the range of 1.6-2.3 μm.
10. The solid state sulfide electrolyte of claim 8 or 9, wherein the solid state sulfide electrolyte has an ionic conductivity in the range of 2.4 to 3.5 ms/cm.

Description

Solid sulfide electrolyte and preparation method thereof Technical Field The invention relates to the technical field of solid-state batteries, in particular to a preparation method of a solid-state sulfide electrolyte and the solid-state sulfide electrolyte prepared by the same. Background In the rapid development of solid-state battery technology, solid-state sulfide electrolytes have been the focus of attention in scientific research and industry due to their excellent electrical properties, high ionic conductivity, and good compatibility with positive electrode materials. LPSC (Lithium Phosphorus Sulfur Chloride ) solid sulfide electrolyte is outstanding as the electrolyte, and performance indexes such as ionic conductivity, electronic conductivity, chemical stability, consistency and dispersibility with a positive electrode material are important for the performance and reliability of a solid battery. Currently, the industry is evaluating LPSC the solid sulfide electrolyte for electrical performance as a primary consideration, but consistency of LPSC solid sulfide electrolyte and uniformity of dispersion with the positive electrode particles are also key points that are not negligible. This is because the uniformity of LPSC solid state sulfide electrolyte directly affects its conductivity, uniformity of dispersion, electrochemical performance, and rate and cycle performance of the battery, while the superior performance exhibited by high uniformity LPSC solid state sulfide electrolyte during processing is an important guarantee for mass production of solid state batteries. Despite the widespread interest in the electrical properties of LPSC solid state sulfide electrolytes, the prior art lacks effective solutions as to how to simultaneously improve the uniformity of the electrolyte itself and its dispersibility with the positive electrode particles, and in particular to achieve uniformity and uniform dispersion of the material while ensuring high conductivity is a challenge faced by the current art. There is relatively little report and discussion of the consistency of LPSC solid sulfide electrolytes in the industry, which shows that there is a clear technical gap and search need in this area. The conventional LPSC solid sulfide electrolyte preparation process is often limited by optimization of parameters such as grinding time, zirconia ball size, precursor selection, and the like. These parameters have a decisive influence on the final consistency of the electrolyte, but in practice it is often difficult to achieve the desired consistency and dispersion of the combination of different parameters, especially when mass production is sought. In the prior art, the preparation of a coherent LPSC solid sulfide electrolyte is highly dependent on the specific equipment performance and morphology and particle size of the precursor. This dependence not only limits the flexibility of the process, but also makes it difficult to control the consistency and dispersion uniformity of the material stably, especially in mass production, where stability between batches becomes a significant technical bottleneck. In view of the above, the prior art has significant limitations in terms of consistency and dispersion uniformity of LPSC solid sulfide electrolyte materials. Therefore, it is of great importance to research and develop a method that can produce a consistent solid sulfide electrolyte independent of precursor morphology, particle size, and equipment consistency. Disclosure of Invention The invention mainly aims to provide a preparation method of a solid sulfide electrolyte and the solid sulfide electrolyte prepared by the method, in particular to LPSC solid sulfide electrolyte, so as to solve the technical problem that the consistency of the solid sulfide electrolyte in the prior art depends on the morphology, granularity and equipment matching of a precursor, and further causes the limitation of the applicability of a preparation process. In order to achieve the above purpose, the invention provides a preparation method of a solid sulfide electrolyte, which comprises the steps of S1, mixing phosphorus pentasulfide, lithium sulfide and lithium chloride with a first solvent, performing ball milling to obtain a precursor, S2, performing heat treatment on the precursor to obtain precursor powder, S3, performing tabletting treatment on the precursor powder to obtain a flaky precursor, S4, sintering the flaky precursor under inert protective atmosphere to obtain a sintered product, S5, mixing the sintered product with a second solvent, performing fractional liquid-phase grinding to obtain a fractional grinding end product, and S6, performing heat treatment on the fractional grinding end product to obtain the solid sulfide electrolyte. Further, in step S3, the pressure used in the tabletting is 100 to 240mpa, and the time of the tabletting is 2 to 5 minutes. Further, in step S5, the fractional liquid phase grinding in