A method for the rapid dry mixing and sintering heat treatment preparation of sulfide electrolytes

Abstract

The application discloses a method for preparing a sulfide electrolyte through rapid dry mixing and sintering heat treatment, and steps of the method comprise the following steps: S1, under an inert atmosphere, ingredients of Li2S, P2S5, LiCl and LiBr are weighed according to stoichiometric ratios; S2, the ingredients obtained in S1 are subjected to high-speed dry mixing to obtain a uniform precursor; and S3, the precursor obtained in S2 is subjected to sintering heat treatment, and then is cooled and crushed to obtain the sulfide electrolyte. 5.5 PS 4.5 Cl 1‑x Br x The room-temperature ionic conductivity of the electrolyte obtained through the method reaches 12-18 mS cm ‑1 , the assembled all-solid-state battery is stable in interface and low in cost, and the sulfide all-solid-state battery industrialization is significantly promoted.

Description

Technical Field

[0001] This application relates to the field of all-solid-state lithium battery technology, specifically to a method for preparing kilogram-scale chlorobromine-doped halide-rich lithium silver lithium ore-type sulfide superionic conductors. Background Technology

[0002] All-solid-state lithium batteries use non-flammable inorganic solid electrolytes instead of traditional liquid electrolytes, fundamentally eliminating safety hazards such as battery leakage and combustion. They also boast higher energy density and longer cycle life, making them a core development direction for next-generation energy storage and power batteries. Among numerous solid electrolyte systems, sulfide electrolytes are considered one of the most promising for industrialization due to their extremely high room-temperature ionic conductivity, good mechanical ductility, and low interfacial impedance.

[0003] Lithium-silver-germanium sulfide electrolytes (such as Li6PS5X, where X = Cl, Br) can have their point defect structure further optimized through halogen multi-component doping, thereby improving ion conductivity. However, existing sulfide electrolytes face serious process bottlenecks in large-scale preparation: traditional high-energy ball milling mechanochemical synthesis typically takes more than 10 hours, and single-batch yields are mostly limited to the gram to ten-gram range, resulting in high energy consumption and poor batch-to-batch uniformity; while liquid-phase synthesis requires the introduction of large amounts of organic solvents, leading to solvent residues, high solvent recovery costs, and environmental pollution. The lack of large-scale, efficient preparation capabilities severely restricts the industrialization of sulfide all-solid-state batteries. Furthermore, many of the high-conductivity sulfide electrolytes reported so far rely on extremely expensive elements such as Ge, Sb, and Nb, which not only significantly increases material costs but also results in a narrow electrochemical window for reaction with high-voltage cathodes, leading to poor interfacial stability and insufficient cycle life. Therefore, how to develop a low-cost, simple process for preparing sulfide electrolytes that can achieve stable kilogram-level scale-up and combines high ionic conductivity with excellent interfacial stability is a key technical challenge that urgently needs to be solved in the field of all-solid-state batteries. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing sulfide electrolytes by rapid dry mixing and sintering heat treatment. This method is highly efficient and energy-saving, and suitable for large-scale scale-up. Based on this method, all-solid-state lithium batteries with high room temperature ionic conductivity and high electrochemical stability can be prepared.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing sulfide electrolytes by rapid dry mixing and sintering heat treatment includes the following steps: S1 is in the glove box, with Li2S, P2S5, LiCl, and LiBr arranged in the order of Li 5.5 PS 4.5 Cl1-x Br x Weigh and mix ingredients according to stoichiometric ratio; S2 involves high-speed dry mixing of the ingredients obtained in S1 to obtain a uniform precursor. S3 subjected the precursor obtained from S2 to sintering heat treatment, followed by cooling and pulverizing to obtain sulfide electrolyte.

[0006] In step S2, the high-speed dry mixer operates at a speed of 25,000 to 35,000 rpm, and the mixing time is 2 to 4 minutes.

[0007] In step S3, the heating rate of the sintering heat treatment is 5~10 ℃ min. -1 .

[0008] In step S3, the sintering heat treatment temperature is 500~550 ℃.

[0009] In step S3, the holding time for sintering heat treatment is 8~10 h.

[0010] In step S3, the prepared sulfide electrolyte has a room temperature ionic conductivity of 12–18 mS / cm. -1 .

[0011] The beneficial effects of this invention: This invention employs a high-speed dry mixing and sintering heat treatment process to prepare sulfide electrolytes with a chemical composition of Li. 5.5 PS 4.5 Cl 1-x Br x This invention has the advantages of high efficiency and energy saving, and high batch consistency, solving the problems of low synthesis efficiency and high energy consumption in traditional methods. Therefore, the all-solid-state battery exhibits excellent long-term cycle performance and rate performance. Attached Figure Description

[0012] Figure 1 Flowchart of rapid dry mixing and sintering heat treatment process; Figure 2 This is a diagram of the inside of a crusher. Detailed Implementation

[0013] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0014] The specific embodiments of the present invention will be described in further detail below with reference to examples. The following detailed descriptions are illustrative and intended to provide further explanation of this application, rather than limiting the scope of the invention.

[0015] As described in the background section, this invention relates to the field of sulfide electrolyte preparation technology, and specifically to a highly conductive Cl / Br dual-doped halide-rich lithium silver germanium sulfide electrolyte Li based on a high-speed dry mixing and sintering heat treatment process. 5.5 PS 4.5 Cl 1-x Br x This invention discloses a kilogram-scale preparation method for LPSCB (Lithium Sulfide Electrolyte), which includes electrolyte molding, performance characterization, and all-solid-state lithium battery assembly. This process overcomes the technical bottlenecks of low efficiency, small batch sizes, and uneven performance in traditional sulfide electrolyte preparation, achieving large-scale, low-cost preparation of high-ionic-conductivity sulfide electrolytes, suitable for the industrial production of all-solid-state lithium batteries. Specifically, it includes the following steps: S1: Press Li 5.5 PS 4.5 Cl 1-x Br x Stoichiometric ratios were used, and high-purity, impurity-free raw materials were selected. All weighing operations were carried out in a glove box protected by inert gas (argon / nitrogen), and the water and oxygen content in the glove box was controlled to be <0.1 ppm to avoid deliquescence or chemical reactions caused by contact with air and moisture, thus ensuring the purity of the raw materials. High-precision electronic balances were used for weighing the raw materials, and the proportions were strictly made according to the stoichiometric ratios to ensure the sufficiency of subsequent reactions and the phase purity of the products. S2: Add the weighed Li2S, P2S5, LiCl and LiBr raw materials into the hopper of the pulverizer, adjust the speed of the pulverizer to 25000~35000 rpm, and continue to dry mix for 2~4 minutes to obtain a uniform solid raw material mixture. S3: Transfer the dry-mixed raw material mixture to a high-temperature furnace inside the glove box, at 5~10 ℃ min. -1 The heating rate is increased to 500 ℃~550 ℃ and held for 8~10 h; then naturally cooled to room temperature to avoid defects such as lattice distortion and cracks caused by rapid cooling, and to ensure the integrity of the crystal structure of the product; the cooled product is pulverized again to obtain LPSCB sulfide electrolyte powder with a particle size of micron, and the pulverized product is sealed and stored in a glove box. Example 1

[0016] S1: In the glove box, place Li2S, P2S5, LiCl, and LiBr in the order of Li 5.5 PS 4.5 Cl 0.45 Br 1.05 The ingredients are weighed and mixed according to the stoichiometric ratio, and the total mass of a single batch is 1.0 kg.

[0017] S2: The ingredients obtained in S1 are subjected to high-speed dry mixing at a speed of 25,000 rpm for 2 minutes to produce uniform precursor powder.

[0018] S3: The precursor obtained in S2 is subjected to heat treatment at a heating rate of 5 °C / min. -1 The sintering temperature was 500 ℃, and the holding time was 8 h. After natural cooling in the furnace, the electrolyte was removed and depolymerized in a pulverizer. The prepared sulfide electrolyte was tested and found to have an ionic conductivity of 12 mS / cm at room temperature. -1 . Example 2

[0019] S1: In the glove box, mix Li₂S, P₂S₅, LiCl, and LiBr in the order Li₅.₅PS₄.₅Cl. 0.55 Br 0.95 The ingredients are weighed and mixed according to the stoichiometric ratio, and the total mass of a single batch is 1.0 kg.

[0020] S2: The ingredients obtained in S1 are subjected to high-speed dry mixing at a speed of 25,000 rpm for 2 minutes to produce uniform precursor powder.

[0021] S3: The precursor obtained in S2 is subjected to sintering heat treatment at a heating rate of 5 °C / min. -1 The sintering temperature was 500 ℃, and the holding time was 8 h. After natural cooling in the furnace, the electrolyte was removed and depolymerized in a pulverizer. The prepared sulfide electrolyte was tested and found to have an ionic conductivity of 14 mS / cm at room temperature. -1 . Example 3

[0022] S1: In the glove box, mix Li₂S, P₂S₅, LiCl, and LiBr in the order Li₅.₅PS₄.₅Cl. 0.65 Br 0.85 The ingredients are weighed and mixed according to the stoichiometric ratio, and the total mass of a single batch is 1.2 kg.

[0023] S2: The ingredients obtained in S1 are subjected to high-speed dry mixing at a speed of 30,000 rpm for 3 min, resulting in a uniform precursor powder.

[0024] S3: The precursor obtained in S2 is subjected to heat treatment at a heating rate of 5 °C / min. -1 The sintering temperature was 520 ℃, and the holding time was 9 h. After natural cooling in the furnace, the electrolyte was removed and depolymerized in a pulverizer. The prepared sulfide electrolyte was tested and found to have an ionic conductivity of 16 mS / cm at room temperature. -1 . Example 4

[0025] S1: In the glove box, place Li2S, P2S5, LiCl, and LiBr in the order of Li 5.5 PS 4.5 Cl 0.75 Br 0.75 The ingredients are weighed and mixed according to the stoichiometric ratio, and the total mass of a single batch is 1.2 kg.

[0026] S2: The ingredients obtained in S1 are subjected to high-speed dry mixing at a speed of 30,000 rpm for 3 min, resulting in a uniform precursor powder.

[0027] S3: The precursor obtained in S2 is subjected to heat treatment at a heating rate of 10 °C min. -1 The sintering temperature was 520 ℃, and the holding time was 9 h. After natural cooling in the furnace, the electrolyte was removed and depolymerized in a pulverizer. The prepared sulfide electrolyte was tested and found to have an ionic conductivity of 18 mS / cm at room temperature. -1 . Example 5

[0028] S1: In the glove box, place Li2S, P2S5, LiCl, and LiBr in the order of Li 5.5 PS 4.5 Cl 0.85 Br 0.65 The ingredients are weighed and mixed according to the stoichiometric ratio, and the total mass of a single batch is 1.5 kg.

[0029] S2: The ingredients obtained in S1 are subjected to high-speed dry mixing at a speed of 35,000 rpm for 4 min, resulting in a uniform precursor powder.

[0030] S3: The precursor obtained in S2 is subjected to heat treatment at a heating rate of 10 °C min. -1 The sintering temperature was 550 ℃, and the holding time was 10 h. After natural cooling in the furnace, the electrolyte was removed and depolymerized in a pulverizer. The prepared sulfide electrolyte was tested and found to have an ionic conductivity of 15 mS / cm at room temperature. -1 . Example 6

[0031] S1: In the glove box, place Li2S, P2S5, LiCl, and LiBr in the order of Li 5.5 PS 4.5 Cl 0.95 Br 0.55 The ingredients are weighed and mixed according to the stoichiometric ratio, and the total mass of a single batch is 1.5 kg.

[0032] S2: The ingredients obtained in S1 are subjected to high-speed dry mixing at a speed of 35,000 rpm for 4 min, resulting in a uniform precursor powder.

[0033] S3: The precursor obtained in S2 is subjected to heat treatment at a heating rate of 10 °C min. -1 The sintering temperature was 550 ℃, and the holding time was 10 h. After natural cooling in the furnace, the electrolyte was removed and depolymerized in a pulverizer. The prepared sulfide electrolyte was tested and found to have an ionic conductivity of 13 mS / cm at room temperature. -1 .

[0034] Table 1: Reaction conditions for Examples 1-6

[0035] Table 2: Performance data for Examples 1-6;

[0036] Table 3: Li 5.5 PS 4.5 Cl 1-x Br x Comparative data with traditional systems;

[0037] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for preparing sulfide electrolytes through rapid dry mixing and sintering heat treatment, characterized in that, Includes the following steps: S1. In the glove box, place Li₂S, P₂S₅, LiCl, and LiBr in the order of Li 5.5 PS 4.5 Cl 1-x Br x Weigh and mix ingredients according to stoichiometric ratio; S2. The ingredients obtained in S1 are mixed by high-speed dry mixing to obtain a uniform precursor; S3. The precursor obtained in S2 is subjected to sintering heat treatment, followed by cooling and pulverization to obtain sulfide electrolyte.

2. The preparation method according to claim 1, a method for preparing sulfide electrolytes by rapid dry mixing and sintering heat treatment, characterized in that, The high-speed dry mixing speed described in S2 is 25,000~35,000 rpm, and the mixing time is 2~4 min.

3. The method for preparing sulfide electrolytes by rapid dry mixing and sintering heat treatment according to claim 1, characterized in that, The heating rate of the sintering heat treatment described in S3 is 5~10 ℃ min. -1 .

4. The method for preparing sulfide electrolytes by rapid dry mixing and sintering heat treatment according to claim 1, characterized in that, The sintering heat treatment temperature described in S3 is 500~550 ℃.

5. The method for preparing sulfide electrolytes by rapid dry mixing and sintering heat treatment according to claim 1, characterized in that, The sintering heat treatment time described in S3 is 8~10 h.

6. The method for preparing sulfide electrolytes by rapid dry mixing and sintering heat treatment according to claim 1, characterized in that, S3 sulfide electrolyte has an ionic conductivity of 12–18 mS / cm at room temperature. -1 .

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