WO-2026095333-A1 - LITHIUM-ION CONDUCTIVE SULFIDE-BASED COMPOUND AND MANUFACTURING METHOD THEREOF

WO2026095333A1WO 2026095333 A1WO2026095333 A1WO 2026095333A1WO-2026095333-A1

Abstract

The present specification relates to a lithium-ion conductive sulfide-based compound, a manufacturing method thereof, and a lithium secondary battery comprising same. More specifically, the present specification relates to a method for obtaining a sulfide-based compound having excellent electrochemical properties by regenerating defective products containing impurities in a sulfide-based solid electrolyte having an argyrodite-type crystal structure.

Inventors

BAEK, HYEON WOO
YANG, A REUM

Assignees

주식회사 에코프로비엠

Dates

Publication Date: 20260507
Application Date: 20250911
Priority Date: 20241028

Claims (11)

(a) A step of preparing a sulfide-based compound containing impurities and having a crystal phase of an argyrodite-type crystal structure; (b) a step of grinding the above sulfide-based compound to obtain particles with a particle size of 100 μm or less; and (c) a step of heat-treating the above particles to obtain a regenerated sulfide-based compound; comprising, Method for manufacturing lithium ion conductive sulfide-based compounds.
In paragraph 1, The crystalline phase of the above azirodite-type crystal structure is represented by the following chemical formula 1, Method for preparing lithium ion-conducting sulfide-based compounds: [Chemical Formula 1] Li 7-x PS 6-x X x In the above chemical formula 1, X is at least one selected from the group consisting of Cl, Br, and I, and 0≤x≤2.
In paragraph 1, The above impurity has at least one peak selected from the group consisting of 2θ values of 14.5°±1°, 27.1°±1°, 29.2°±1°, and 33.9°±1° in Cu-Kα XRD analysis, Method for manufacturing lithium ion conductive sulfide-based compounds.
In paragraph 1, The sulfide compound of step (a) above is prepared by a dry bulk synthesis method, Method for manufacturing lithium ion conductive sulfide-based compounds.
In paragraph 1, The grinding in step (b) above is performed using at least one selected from the group consisting of a ball mill, a pebble mill, a rod mill, a roller mill, a colloid mill, an impact mill, a jet mill, a bead mill, a vibrating mill, a stirring mill, a disc mill, and a grinding classifier mill. Method for manufacturing lithium ion conductive sulfide-based compounds.
In paragraph 1, The heat treatment of step (c) above is performed at 500 to 600°C for 5 to 10 hours, Method for manufacturing lithium ion conductive sulfide-based compounds.
In paragraph 1, I3 /I'3, which is the ratio of the peak intensity I3 observed at wavenumber 565–575 cm⁻¹ in the Raman analysis of the regenerated sulfide-based compound above to the peak intensity I'3 observed at wavenumber 565–575 cm⁻¹ in the Raman analysis of the sulfide-based compound of step (a ) above, is greater than 1, Method for manufacturing lithium ion conductive sulfide-based compounds.
As a sulfide compound containing a crystal phase of an argyrodite-type crystal structure, In Raman analysis, the ratio of the peak intensity I1 observed at wavenumbers 265–275 cm⁻¹ to the peak intensity I₂ observed at 420–430 cm⁻¹ , I₂ / I⁻¹ , which is greater than 12.54, Lithium ion conductive sulfide-based compounds.
In paragraph 8, The above sulfide-based compound does not show peaks in regions where the 2θ values of the Cu-Kα XRD analysis are 14.5°±1°, 27.1°±1°, 29.2°±1°, and 33.9°±1°, Lithium ion conductive sulfide-based compounds.
In paragraph 8, For Raman analysis where I3 / I1 , the ratio of the peak intensity I1 observed at wavenumbers 265–275 cm⁻¹ to the peak intensity I3 observed at 565–575 cm⁻¹ , is greater than 2.22, Lithium ion conductive sulfide-based compounds.
Comprising a lithium ion-conducting sulfide-based compound according to paragraph 8, Lithium secondary battery.

Description

Lithium ion conductive sulfide-based compound and method for manufacturing the same This specification relates to a lithium ion-conducting sulfide-based compound, a method for manufacturing the same, and a lithium secondary battery containing the same. More specifically, this specification relates to a method for obtaining a sulfide-based compound having excellent electrochemical properties by regenerating a defective product containing impurities among a sulfide-based solid electrolyte having an azirodite-type crystal structure. A battery stores electrical power by using materials capable of electrochemical reactions at the positive and negative electrodes. A representative example of such a battery is the lithium secondary battery, which stores electrical energy based on the difference in chemical potential when lithium ions intercalate or deintercalate at the positive and negative electrodes. The above lithium secondary battery is manufactured by using materials capable of reversible intercalation/deintercalation of lithium ions as positive and negative active materials, and by filling an organic electrolyte or a polymer electrolyte between the positive and negative electrodes. However, these organic or polymer electrolytes typically use flammable organic solvents. Therefore, if abnormally high temperatures occur due to internal or external factors of the lithium secondary battery, a fire or explosion may occur due to the electrolyte. Due to these safety concerns, solid-state batteries utilizing solid electrolytes are attracting attention as a substitute for liquid batteries. Solid-state batteries are expected to be commercialized as next-generation batteries with high energy density due to their high stability. Among the solid electrolytes used in lithium-ion batteries, sulfide-based solid electrolytes are currently receiving significant attention. Various crystal structures of sulfide-based solid electrolytes are known, one of which is the argyrodite-type crystal structure. However, sulfide-based solid electrolytes with an agitite-type crystal structure have problems such as high reactivity with moisture and oxygen, complex manufacturing processes, and significant variability in ionic conductivity performance. Furthermore, due to the nature of solid-phase materials, micronization is essential to maximize the contact surface area; however, this grinding process leads to degradation such as amorphization and impurity formation, resulting in reduced ionic conductivity. In particular, impurities can easily form in manufacturing methods utilizing dry bulk synthesis. FIG. 1 is the XRD analysis result of a sulfide-based compound according to one example of the present specification; Figure 2 is the result of a Raman spectrum analysis of a sulfide-based compound according to one example of the present specification. For convenience, specific terms are defined herein to facilitate a better understanding of this specification. Unless otherwise defined herein, scientific and technical terms used in this invention shall have the meanings generally understood by those skilled in the art. Furthermore, unless specifically indicated in the context, terms in their singular form shall be understood to include their plural form, and terms in their plural form shall be understood to include their singular form. Method for manufacturing lithium ion conductive sulfide-based compounds A method for manufacturing a lithium ion-conducting sulfide-based compound according to one aspect of the present specification may include: (a) a step of preparing a sulfide-based compound containing a crystalline phase having an argyrodite-type crystal structure and containing impurities; (b) a step of grinding the sulfide-based compound to obtain particles having a particle size of 100 μm or less; and (c) a step of heat-treating the particles to obtain a regenerated sulfide-based compound. The above step (a) may be a step of preparing a defective product containing impurities that occurs in a conventional step of manufacturing a sulfide-based compound having a crystal phase of an azirodite-type crystal structure. The above sulfide-based compound has lithium ion conductivity and can have a crystal phase with an azirodite-type crystal structure. An azirodite-type crystal structure refers to a structure identical to that of azirodite ( Ag₅GeS₆ ) , a silver-germanium-sulfur mineral. The azirodite-type crystal structure can possess orthorhombic ( Pna₂₁ ) and cubic (F₄³m) phases, among which the cubic crystal structure can exhibit high lithium ion conductivity. Typically, the azirodite-type crystal structure exhibits the cubic phase, which has excellent lithium ion conductivity at high temperatures, and the orthorhombic phase at low temperatures. For example, Li 7 PS 6 and Li 6 PS 5 X (where X is at least one of Cl, Br, and I) are known as lithium ion conductive solid electrolyte compounds having an azirodite-type crystal structure. However, the a