Search

KR-102962200-B1 - Method for producing a sulfide-based solid electrolyte without generation of impurities, and a sulfide-based solid electrolyte prepared by the same

KR102962200B1KR 102962200 B1KR102962200 B1KR 102962200B1KR-102962200-B1

Abstract

The present invention relates to a method for producing a sulfide-based solid electrolyte having high ionic conductivity without the generation of impurities, and to a sulfide-based solid electrolyte produced by the same method. Specifically, the invention is characterized by providing a method for effectively synthesizing a sulfide-based solid electrolyte by raising and cooling a mixed solution containing raw materials in an organic solvent to a specific temperature.

Inventors

  • 최선호
  • 장용준
  • 송인우
  • 이상수
  • 김소영
  • 최성현
  • 김사흠
  • 이상헌

Assignees

  • 현대자동차주식회사
  • 기아 주식회사

Dates

Publication Date
20260507
Application Date
20210223

Claims (12)

  1. A step of preparing a mixed solution by mixing raw materials with an organic solvent; A heating step of heating and stirring the above mixed solution; A cooling step of cooling and stirring the above-mentioned heated mixed solution; A reheating step of heating and stirring the cooled mixed solution; and Includes a heat treatment step; and The above mixed solution is heated to 40°C or higher, and The above mixed solution is cooled to 30°C or lower, and During the heating stage, the stirring is carried out for 30 minutes to 3 hours, and During the cooling phase, the stirring is carried out for 30 minutes to 3 hours, and A method for manufacturing a sulfide-based solid electrolyte, characterized in that the stirring is carried out for 12 to 14 hours during the reheating stage.
  2. In paragraph 1, The above raw materials include lithium sulfide, phosphorus sulfide, and halogen compounds, and A method for manufacturing a sulfide-based solid electrolyte, wherein the organic solvent comprises one selected from the group consisting of ethanol, propanol, butanol, dimethyl carbonate, ethyl acetate, tetrahydrofuran, 1,2-dimethoxyethane, propylene glycol dimethyl ether, acetonitrile, and combinations thereof.
  3. In paragraph 1, In the heating step, the mixed solution is heated at a rate of 1℃/min to 3℃/min, and In the cooling step, the mixed solution is cooled to -1℃/min to -3℃/min, and A method for manufacturing a sulfide-based solid electrolyte, wherein the mixed solution is heated at a rate of 1℃/min to 3℃/min during the reheating step.
  4. In paragraph 1, The above mixed solution is heated to synthesize raw materials, and A method for manufacturing a sulfide-based solid electrolyte, wherein the above mixed solution is cooled to precipitate solid particles.
  5. delete
  6. delete
  7. In paragraph 1, During the heating stage, the stirring is carried out for 5 to 10 minutes at a speed of 150 rpm or less, and then carried out for the remaining time at 250 to 300 rpm. A method for manufacturing a sulfide-based solid electrolyte, wherein in the cooling step, the stirring is carried out at a speed of 150 rpm or less for 5 to 10 minutes, and then at 250 to 300 rpm for the remainder of the time.
  8. In paragraph 1, A method for manufacturing a sulfide-based solid electrolyte in which the above heating step, cooling step, and reheating step are repeated 2 to 3 times.
  9. In paragraph 1, A method for manufacturing a sulfide-based solid electrolyte, further comprising a drying step of drying the mixed solution to remove an organic solvent prior to a heat treatment step.
  10. In paragraph 1, A method for manufacturing a sulfide-based solid electrolyte, wherein in the heat treatment step, solid particles are heat-treated at a temperature of 500°C or higher for 4 to 10 hours.
  11. delete
  12. delete

Description

Method for producing a sulfide-based solid electrolyte without generation of impurities, and a sulfide-based solid electrolyte prepared by the same The present invention relates to a method for producing a sulfide-based solid electrolyte having high ionic conductivity without the generation of impurities, and to a sulfide-based solid electrolyte produced by the same method. Specifically, the invention is characterized by providing a method for effectively synthesizing a sulfide-based solid electrolyte by raising and cooling a mixed solution containing raw materials in an organic solvent to a specific temperature. Rechargeable batteries are used as high-capacity power storage batteries for electric vehicles and battery power storage systems, as well as as high-performance energy sources for small portable electronic devices such as mobile phones, camcorders, and laptops. Research is underway on component lightweighting and low power consumption with the goal of miniaturizing portable electronic devices and enabling long-term continuous use. As a secondary battery, lithium-ion batteries have a higher energy density, larger capacity per unit area, a lower self-discharge rate, and a longer lifespan than nickel-manganese or nickel-cadmium batteries. Furthermore, they are convenient to use and have a long lifespan because they do not have a memory effect. However, lithium-ion batteries are unsuitable for use as batteries for next-generation electric vehicles due to the risk of explosion caused by overheating, low energy density, and low output. In particular, because liquid electrolytes are used, safety issues such as overheating pose a risk of leading to fire. In order to overcome the problems of lithium-ion batteries using liquid electrolytes, research and development of all-solid-state lithium-ion batteries using solid electrolytes have recently been actively underway. All-solid-state lithium-ion batteries have the advantage of having no fire hazard because they use a solid electrolyte, and they can have a bipolar structure, so their volume energy density is more than five times higher than that of conventional lithium-ion batteries. However, solid electrolytes used in all-solid-state lithium-ion batteries have limitations, such as being very expensive and difficult to mass-produce and control particle size. This is the biggest obstacle to the commercialization of all-solid-state lithium-ion batteries. Therefore, research and development on new solid electrolyte manufacturing methods capable of overcoming these limitations is actively underway. Generally, in the manufacture of sulfide-based solid electrolytes, a dry method involving mixing the solid electrolyte precursors using methods such as ball milling was primarily used; however, this method had the problem of being extremely cumbersome, requiring the milling time to be set very long, the milled powder to be separated from the balls, and the powder to be collected without contaminating the external environment. To avoid the aforementioned process inefficiencies, a new method of synthesizing sulfide-based solid electrolytes by reacting raw materials such as Li2S, LiCl, and P2S5 in polar organic solvents was emerging. However, there was a problem in that these raw materials consist of compounds with strong bonding forces, making it difficult to fully dissolve them in polar organic solvents. In other words, because the chemical reactions of the raw materials within the solvent did not proceed actively, there were frequent cases where they precipitated as is without forming a crystal structure. Conventionally, when raw materials or similar substances fail to participate in the reaction and are included in the product, they can act as impurities. Since these impurities cause a decrease in ionic conductivity, methods to reduce or remove such impurities are required. Figure 1 shows a process flowchart for the method of manufacturing a sulfide-based solid electrolyte according to the present invention. Figure 2 shows the XRD analysis results for the sulfide-based solid electrolytes prepared in the examples and comparative examples. Figure 3 shows the results of Raman analysis for the sulfide-based solid electrolytes prepared in the examples and comparative examples. The above objects, other objects, features, and advantages of the present invention will be easily understood through the following preferred embodiments associated with the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided to ensure that the disclosed content is thorough and complete and to ensure that the spirit of the invention is sufficiently conveyed to a person skilled in the art. In this specification, terms such as "comprising" or "having" are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinatio