Halide solid electrolyte and preparation method thereof

Abstract

The invention discloses a halide solid electrolyte and a preparation method thereof.The preparation method comprises the steps that a lithium-containing compound, a yttrium-containing compound and a halogen compound are mixed, and a mixed raw material is obtained; carrying out ball-milling treatment on the mixed raw material to obtain a ball-milled product; transferring the ball-milled product into a muffle furnace, heating the ball-milled product to a preset temperature according to a preset heating rate in an inert gas atmosphere, carrying out heat preservation for a preset heat preservation time at the preset temperature, and then cooling the ball-milled product to room temperature to obtain an initial product; grinding the initial product to obtain the halide solid electrolyte; the general chemical formula of the halide solid electrolyte is Li3YX6, and X is one of Cl, Br, I and F. According to the preparation method, mechanical ball milling and heat treatment processes are combined, so that the reaction temperature of Li3YX6 is effectively reduced, decomposition and volatilization of halide can be prevented, and the prepared electrolyte has higher product purity and more uniform powder particle size and morphology.

Description

Technical Field

[0001] This application relates to the field of all-solid-state battery technology, and in particular to a halide solid electrolyte and its preparation method. Background Technology

[0002] Currently, with the advancement of technology and the rapid development of 3C electronic products and electric vehicles, people have increasingly higher requirements for various energy storage devices. Lithium-ion batteries have received widespread attention in recent years due to their advantages such as high energy density, long cycle life, high operating voltage, and low environmental pollution. However, traditional lithium-ion batteries still focus on liquid electrolyte batteries, which use flammable, corrosive, and thermally unstable organic solvents as electrolytes. This poses significant safety risks in terms of electrochemical and thermal stability, and also fails to meet the market demand for large-size batteries.

[0003] All-solid-state batteries, due to their use of solid electrolytes instead of liquid electrolytes, offer advantages such as higher safety, higher energy density, and longer cycle life, making them a promising next-generation battery technology. Solid electrolytes are the core material in all-solid-state batteries; therefore, developing solid electrolytes with high comprehensive performance, including a wide electrochemical window, high room-temperature ionic conductivity, excellent chemical stability, and low cost, is a crucial prerequisite for the industrialization of all-solid-state lithium batteries. Sulfide solid electrolytes are considered the most promising inorganic solid electrolytes due to their high ionic conductivity, good mechanical properties, and good thermal stability.

[0004] Despite this, sulfide solid electrolytes still face many challenges. Compared to liquid batteries, their room-temperature ionic conductivity remains low, and issues such as interfacial compatibility and interfacial side reactions between the electrolyte and cathode materials within the battery still need to be addressed. Halogen materials are attractive due to the properties of halide anions, although they have received relatively little attention. Monovalent halide anions, due to their weaker interaction with lithium ions compared to divalent sulfur or oxygen anions and their larger ionic radii, result in longer ionic bond lengths and higher polarizability, potentially accelerating lithium-ion transport and achieving high lithium-ion mobility. Furthermore, some inorganic halide salts, especially those with high ionicity, remain stable even at high temperatures in dry air. This leads to high electrochemical oxidation stability in chlorides and bromides. Despite these advantageous anionic properties, research on halide electrolytes is relatively limited. In recent years, halides have been considered to combine the advantages of sulfide and oxide solid electrolytes, such as being as dense as sulfides at room temperature but having better compatibility with high-voltage cathodes. They decompose when exposed to humid air but do not produce toxic H2S gas, thus attracting widespread attention.

[0005] In recent years, halide solid electrolytes, especially ternary halides Li3YBr6, have emerged as promising next-generation solid electrolytes due to their high ionic conductivity (>1 mS / cm) and good stability and compatibility with high-voltage cathodes (such as LiCo2 / NCM). Currently, Li3YBr6 is mainly synthesized via high-temperature solid-state methods, which involve high reaction temperatures, high energy consumption, and the high temperatures can easily lead to bromine volatilization and non-stoichiometry of the products, as well as a lack of effective control over the product morphology. Summary of the Invention

[0006] This application provides a halide solid electrolyte and its preparation method. By combining mechanical ball milling and heat treatment processes, the reaction temperature of Li3YX6 is effectively reduced, which can prevent the decomposition and volatilization of halides. The prepared electrolyte has higher product purity and more uniform powder particle size and morphology.

[0007] On one hand, this application provides a method for preparing a halide solid electrolyte, the method comprising: A mixed raw material is obtained by mixing a lithium-containing compound, a yttrium-containing compound, and a halogen compound. The mixed raw materials are ball-milled to obtain the ball-milled product; The ball-milled product is transferred to a muffle furnace and heated to a preset temperature at a preset heating rate under an inert gas atmosphere. The product is then held at the preset temperature for a preset holding time and subsequently cooled to room temperature to obtain the initial product. The initial product is ground to obtain the halide solid electrolyte; the chemical formula of the halide solid electrolyte is Li3YX6, where X is one of Cl, Br, I, and F.

[0008] Furthermore, the preset heating rate is 1℃ / min-5℃ / min; The preset temperature is 200℃-600℃; The preset heat preservation time is 2 h-10 h.

[0009] Furthermore, the mixing of the lithium-containing compound, the yttrium-containing compound, and the halogen compound to obtain a mixed raw material includes; The lithium-containing compound, the yttrium-containing compound, and the halogen compound were placed in a glove box, and the lithium-containing compound, the yttrium-containing compound, and the halogen compound were weighed according to a preset molar ratio. The weighed raw materials are mixed to obtain the mixed raw materials.

[0010] Further, the ball milling treatment of the mixed raw materials to obtain the ball milled product includes: The mixed raw materials are placed in a ball mill jar, and zirconia balls are added. The ball mill jar is then sealed to obtain a sealed ball mill jar. The sealed ball mill jar is transferred from the glove box to the ball mill to ball mill the mixed raw materials and obtain the ball milled product.

[0011] Furthermore, the lithium-containing compound is one or more of LiH, Li2CO3, LiCl, LiBr, LiI, LiF, LiS, and LiSe; The yttrium-containing compound is one or more of YCl3, YBr3, YI3, and Y2(CO3)3; The halogen compound is one or more of LiCl, LiBr, LiI, and LiF.

[0012] Furthermore, the diameter of the zirconia spheres is 1 mm to 10 mm; The ratio of the zirconium oxide spheres to the mixed raw materials is in the range of 5:1 to 20:1; During the ball milling process, the rotation speed of the ball mill is 50 rpm-250 rpm, and the milling time is 2 h-12 h.

[0013] Further, the grinding of the initial product to obtain the halide solid electrolyte includes: The initial product is ground to obtain a ground powder; The ground powder is sieved to obtain the halide solid electrolyte.

[0014] Furthermore, the size of the sieve used in the sieving process is 40-60 mesh; The particle size of the electrolyte particles in the halide solid electrolyte is 100 nm-200 nm.

[0015] Further, the general chemical formula of the halide solid electrolyte is Li3YBr6. The ball-milled product is transferred to a muffle furnace and heated to a preset temperature at a preset heating rate under an inert gas atmosphere, and held at the preset temperature for a preset holding time, followed by cooling to room temperature to obtain the initial product, comprising: The ball-milled product is transferred to a crucible, and the crucible is placed in the muffle furnace and heated to 250°C-450°C at a heating rate of 1°C / min-2°C / min under the inert gas atmosphere. The initial product was obtained by holding the product at 250℃-450℃ for 4-8 hours and then cooling it to room temperature.

[0016] On the other hand, a halide solid electrolyte is provided, which is prepared by the above-described method for preparing halide solid electrolytes.

[0017] The halide solid electrolyte and its preparation method provided in this application have the following technical advantages: This application involves mixing a lithium-containing compound, a yttrium-containing compound, and a halogen compound to obtain a mixed raw material; ball milling the mixed raw material to obtain a ball-milled product; transferring the ball-milled product to a muffle furnace and heating it to a preset temperature at a preset heating rate under an inert gas atmosphere, holding it at the preset temperature for a preset holding time, and then cooling it to room temperature to obtain an initial product; grinding the initial product to obtain a halide solid electrolyte; the general chemical formula of the halide solid electrolyte is Li3YX6, where X is one of Cl, Br, I, and F. This application combines mechanical ball milling with heat treatment to effectively reduce the reaction temperature of Li3YX6, preventing the decomposition and volatilization of halogen compounds. The resulting halide solid electrolyte has uniform particle size and morphology, significantly improving its air stability. By controlling the ball milling and heat treatment process parameters, the electrolyte morphology can be regulated. Furthermore, the preparation method provided in this application is simpler, more convenient to operate, and lower in cost. The resulting electrolyte product has high purity, high ionic conductivity, good compatibility with the positive electrode, and excellent electrochemical performance.

[0018] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0019] To more clearly illustrate the technical solutions and advantages in the embodiments or prior art of this specification, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic flowchart of a method for preparing a halide solid electrolyte provided in the embodiments of this specification; Figure 2 This is a schematic flowchart of a method for obtaining mixed raw materials provided in the embodiments of this specification; Figure 3 This is a schematic flowchart of a method for obtaining ball-milled products provided in the embodiments of this specification; Figure 4 This is the X-ray diffraction pattern of Li3YBr6 prepared in Example 8 provided in this specification; Figure 5 This is the X-ray diffraction pattern of Li3YBr6 prepared in Example 13 provided in this specification; Figure 6 This is the X-ray diffraction pattern of Li3YBr6 prepared in Comparative Example 1 provided in the embodiments of this specification; Figure 7 This is the electrochemical impedance spectroscopy of Li3YBr6 prepared in Example 8 provided in this specification; Figure 8 This is the electrochemical impedance spectroscopy of Li3YBr6 prepared in Example 13 provided in this specification; Figure 9 This is an electron microscope image of Li3YBr6 prepared in Example 8 provided in this specification. Detailed Implementation

[0021] The technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] The following describes a method for preparing a halide solid electrolyte according to this application, specifically as follows: Figure 1 As shown, the method may include: S1: A lithium-containing compound, a yttrium-containing compound, and a halogen compound are mixed to obtain a mixed raw material; S2: The mixed raw materials are ball-milled to obtain the ball-milled product; S3: Transfer the ball-milled product to a muffle furnace, heat it to a preset temperature at a preset heating rate under an inert gas atmosphere, hold it at the preset temperature for a preset holding time, and then cool it to room temperature to obtain the initial product; S4: Grind the initial product to obtain the halide solid electrolyte; the chemical formula of the halide solid electrolyte is Li3YX6, where X is one of Cl, Br, I, and F.

[0023] In this embodiment of the application, in order to prepare the ternary halide electrolyte Li3YX6, a lithium-containing compound, a yttrium-containing compound, and a halogen compound are used as raw materials. First, the raw materials are mixed and then ball-milled. The ball-milled product is then transferred to a muffle furnace and heat-treated in an inert gas atmosphere. The heating program of the muffle furnace can be set to heat to a preset temperature at a preset heating rate. After reaching the preset temperature, the product is held at that temperature. After the holding time reaches the preset holding time, the product is cooled to room temperature to obtain the heat-treated product, i.e., the initial product mentioned above. The initial product is taken out of the muffle furnace and ground to obtain the final halide solid electrolyte powder.

[0024] Currently, the synthesis of Li3YBr6 mainly relies on high-temperature solid-state methods. These methods involve high reaction temperatures and energy consumption, and the high temperatures can easily lead to bromine volatilization and non-stoichiometry of the product, while also lacking effective control over the product morphology. In this application, a combination of mechanical ball milling and heat treatment effectively reduces the reaction temperature of Li3YBr6, preventing the decomposition and volatilization of halogen compounds. The resulting halide solid electrolyte exhibits uniform particle size and morphology. Furthermore, the preparation method provided in this application is simpler, more convenient to operate, and lower in cost. The resulting electrolyte product has high purity, high ionic conductivity, and good compatibility with the cathode, making it suitable for all-solid-state batteries.

[0025] Furthermore, the preset heating rate is 1℃ / min-5℃ / min; The preset temperature is 200℃-600℃; The preset heat preservation time is 2 h - 10 h.

[0026] In this embodiment of the application, when using a muffle furnace to heat treat the ball milled product, a corresponding heating program needs to be set. The preset heating rate can be 1℃ / min-5℃ / min, preferably 1℃ / min-2℃ / min, the preset temperature is 200℃-600℃, preferably 250℃-450℃, and the preset holding time is 2 h-10 h, preferably 4 h-8 h.

[0027] For example, the inert gas can be nitrogen or argon. Heat treatment in an inert gas atmosphere can effectively isolate oxygen in the air, prevent the electrolyte material from undergoing oxidation at high temperatures, and prevent metallic elements or oxygen-sensitive components in the electrolyte material from reacting with oxygen at high temperatures to form oxides, thereby changing the chemical composition and properties of the material. The inert gas environment can also prevent the material from being contaminated by impurities in the air, ensuring the high purity of the electrolyte and preventing impurities from affecting the ionic conductivity and interfacial stability of the electrolyte. In addition, heat treatment of the ball-milled product in an inert gas atmosphere can more accurately control the morphology of the product, so that the final halide solid electrolyte has better electrochemical performance.

[0028] This application combines ball milling with solid-state methods to heat-treat the ball milling product, which can reduce the calcination temperature of the solid electrolyte, prevent the volatilization of halogen elements, and control the morphology of the electrolyte by controlling the heat treatment temperature.

[0029] Furthermore, such as Figure 2 As shown, the process of mixing a lithium-containing compound, a yttrium-containing compound, and a halogen compound to obtain a mixed raw material includes: S11: Place the lithium-containing compound, the yttrium-containing compound, and the halogen compound in a glove box, and weigh the lithium-containing compound, the yttrium-containing compound, and the halogen compound according to a preset molar ratio. S12: Mix the weighed raw materials to obtain the mixed raw materials.

[0030] In this embodiment, the raw materials required for preparation can first be transferred to an inert atmosphere glove box, and the raw materials, namely the lithium-containing compound, the yttrium-containing compound, and the halogen compound, are weighed according to a preset molar ratio. After weighing, they are mixed to obtain a mixed raw material. For example, the inert atmosphere glove box can be a nitrogen atmosphere glove box. Mixing the three raw materials in the inert atmosphere glove box can isolate external oxygen and moisture, preventing the decomposition and volatilization of reactants. In addition, the sealed environment inside the glove box can prevent the introduction of external contamination and prevent it from affecting the conductivity and purity of the electrolyte.

[0031] For example, the above-mentioned preset molar ratio is 3:1:6, that is, the molar ratio of the three elements Li, Y and X in each raw material is 3:1:6.

[0032] In this embodiment, the raw materials are mixed in a glove box, which avoids the decomposition and volatilization of the reactants, and makes the prepared electrolyte have good chemical stability and performance consistency.

[0033] Furthermore, such as Figure 2As shown, the ball milling process of the mixed raw materials to obtain the ball milled product includes: S21: Place the mixed raw materials in a ball mill jar, add zirconia balls, and then seal the ball mill jar to obtain a sealed ball mill jar; S22: The sealed ball mill jar is transferred from the glove box to the ball mill to ball mill the mixed raw materials to obtain the ball milled product.

[0034] In this embodiment, after mixing the raw materials to obtain a mixed raw material, the mixed raw material is placed in a ball mill jar, and milling balls are added. The jar is then sealed to obtain a sealed ball mill jar, preventing external air or impurities from affecting subsequent reactions and preventing the decomposition and volatilization of reactants. The sealed ball mill jar is then transferred from a glove box to a ball mill to ball mill the mixed raw material, obtaining the ball-milled product, i.e., the precursor.

[0035] For example, the grinding balls described above can be zirconia balls.

[0036] In this embodiment, the mixed raw materials are ball-milled to preliminarily control the particle size and morphology of the electrolyte. By mixing in a glove box and sealing the ball milling jar before ball milling, the volatilization of the reactants can be effectively prevented, thereby obtaining an electrolyte with high ionic conductivity, high voltage positive electrode stability and compatibility.

[0037] Furthermore, the lithium-containing compound is one or more of LiH, Li2CO3, LiCl, LiBr, LiI, LiF, LiS, and LiSe; The yttrium-containing compound is one or more of YCl3, YBr3, YI3, and Y2(CO3)3; The halogen compound is one or more of LiCl, LiBr, LiI, and LiF.

[0038] In the embodiments of this application, the lithium-containing compound can be one or more of LiH, Li₂CO₃, LiCl, LiBr, LiI, LiF, LiS, and LiSe. Furthermore, the Li source can also be elemental lithium metal. The yttrium-containing compound, i.e., the Y source, can be one or more of YCl₃, YBr₃, YI₃, and Y₂(CO₃)₃. The halogen compound can be one or more of LiCl, LiBr, LiI, and LiF. Furthermore, the X source can also be elemental iodine. By using the above raw materials, halide solid electrolytes can be prepared at a lower cost. Furthermore, using inorganic halide salts as one of the raw materials can significantly improve the air stability of the halide solid electrolyte.

[0039] In the embodiments of this application, LiBr can be used as both a Li source and a halogen source. When preparing mixed raw materials, only LiBr and another raw material (e.g., YBr3) need to be weighed.

[0040] The embodiments of this application provide a diverse range of raw material selections for the preparation of halide solid electrolytes, enabling the selection of appropriate raw materials according to actual preparation needs, thereby improving the applicability of the halide solid electrolyte preparation method.

[0041] Furthermore, the diameter of the zirconia spheres is 1 mm to 10 mm; The ratio of the zirconium oxide spheres to the mixed raw materials is in the range of 5:1 to 20:1; During the ball milling process, the rotation speed of the ball mill is 50 rpm-250 rpm, and the milling time is 2 h-12 h.

[0042] In this embodiment, for ball milling, zirconia balls can be used, wherein the size of the zirconia balls can be φ1-φ10, preferably φ10; the ball-to-material ratio between the zirconia balls and the mixed raw materials can be 5:1-20:1, preferably 10:1-20:1; the rotational speed of the ball mill can be set to 50 rpm-250 rpm, preferably 150 rpm-250 rpm; and the ball milling time can be 2 h-12 h, preferably 4 h-10 h. By reasonably controlling the various experimental parameters during ball milling, the particle size and morphology of the product can be effectively controlled, so that the prepared electrolyte has a more uniform particle size and morphology.

[0043] The embodiments of this application can reasonably control the particle size and morphology of the product by selecting appropriate ball milling experimental parameters, so that the product has uniform particle size and morphology.

[0044] Further, the grinding of the initial product to obtain the halide solid electrolyte includes: The initial product is ground to obtain a ground powder; The ground powder is sieved to obtain the halide solid electrolyte.

[0045] In this embodiment of the application, after the initial product is obtained by heat treatment, the initial product in the muffle furnace may be in block form. In order to process the block product into a uniform powder product, the cooled electrolyte block can be taken out from the muffle furnace and placed in a mortar for grinding. The ground powder is then sieved to make the powder particle size more uniform, so as to obtain the final halide solid electrolyte powder.

[0046] The embodiments of this application, by grinding and sieving the product obtained after heat treatment, enable the final halide solid electrolyte to have a more uniform powder particle size.

[0047] Furthermore, the size of the sieve used in the sieving process is 40-60 mesh; The particle size of the electrolyte particles in the halide solid electrolyte is 100 nm-200 nm.

[0048] In the embodiments of this application, when using a sieve for sieving, the sieve mesh can be 40-60 mesh, preferably 40 mesh.

[0049] In the embodiments of this application, after grinding and sieving, the particle size of the electrolyte particles in the final halide solid electrolyte is between 100 nm and 200 nm, indicating that the final electrolyte product has a uniform powder particle size.

[0050] The embodiments of this application utilize sieves of appropriate specifications to effectively control the uniform particle size of the final electrolyte product, thereby preparing halide solid electrolyte powder with controllable particle size.

[0051] Further, the general chemical formula of the halide solid electrolyte is Li3YBr6. The ball-milled product is transferred to a muffle furnace and heated to a preset temperature at a preset heating rate under an inert gas atmosphere, and held at the preset temperature for a preset holding time, followed by cooling to room temperature to obtain the initial product, comprising: The ball-milled product is transferred to a crucible, and the crucible is placed in the muffle furnace and heated to 250°C-450°C at a heating rate of 1°C / min - 2°C / min under the inert gas atmosphere. The initial product was obtained by holding the product at 250℃-450℃ for 4-8 hours and then cooling it to room temperature.

[0052] In this embodiment of the application, if the chemical formula of the halide solid electrolyte is Li3YBr6, the above-mentioned heat treatment step may include: transferring the ball-milled product to a muffle furnace and heating it to 250℃-450℃ at a heating rate of 1℃ / min-2℃ / min under an inert gas atmosphere; after heating to the above temperature, holding it at that temperature for 4 h-8 h; after holding it at that temperature, cooling it to room temperature to obtain the heat-treated product, i.e., the above-mentioned initial product.

[0053] Existing high-temperature solid-state methods involve high reaction temperatures and energy consumption. Furthermore, high temperatures can easily lead to bromide volatilization and non-stoichiometry of products, and the morphology of the products lacks effective control. Therefore, compared with existing high-temperature solid-state methods, this application combines mechanical ball milling with heat treatment to effectively reduce the reaction temperature of Li3YXBr6, prevent the decomposition and volatilization of bromides, and obtain a halide solid electrolyte with uniform powder particle size and morphology. In addition to good air stability, it also has high ionic conductivity, high voltage cathode stability, and compatibility.

[0054] This application embodiment combines mechanical ball milling with heat treatment, which can effectively reduce the reaction temperature of Li3YXBr6, prevent the decomposition and volatilization of bromides, and the preparation process is simple and convenient. Moreover, ball milling and heat treatment can effectively control the morphology of the electrolyte, resulting in a halide solid electrolyte with uniform powder particle size and morphology.

[0055] This application combines mechanical ball milling with heat treatment to effectively reduce the reaction temperature of Li3YX6, preventing the decomposition and volatilization of halogen compounds. The resulting halide solid electrolyte exhibits uniform particle size and morphology, significantly improving its air stability. By controlling the ball milling and heat treatment parameters, the electrolyte morphology can be regulated. Furthermore, the preparation method provided in this application is simpler, more convenient, and lower in cost, resulting in an electrolyte product with high purity, high ionic conductivity, good compatibility with the cathode, and excellent electrochemical performance. This application also provides a halide solid electrolyte, which can be prepared using the method described above. The chemical formula of the halide solid electrolyte is Li3YX6, where X is one of Cl, Br, I, or F. Li3YX6 exhibits high ionic conductivity, high voltage cathode stability and uniformity, and has uniform particle size and morphology, making it suitable for use in all-solid-state batteries.

[0056] This application also provides an all-solid-state battery comprising the halide solid electrolyte Li3YX6 as described above, wherein X is one of the elements Cl, Br, I, and F.

[0057] Example 1: Example 1 provides a halide solid electrolyte Li3YX6 (X=Br), the preparation method of which includes: In a nitrogen glove box, 7.03 g of LiBr (99.9% purity) and 8.87 g of YBr3 (99% purity) were weighed out according to a certain molar ratio and mixed to obtain a mixed raw material. The above mixed raw materials are placed into a ball mill jar, and φ10 zirconia balls are added at a ball-to-material ratio of 10:1. The ball mill jar is then sealed to obtain a sealed ball mill jar. The sealed ball mill jar was removed from the glove box and placed in a ball mill for ball milling to obtain the ball milled product, namely the precursor powder Li3YBr6. The performance of the prepared precursor was then tested. The ball mill speed was 200 rpm and the ball milling time was 4 h.

[0058] Example 2: Example 2 provides a halide solid electrolyte Li3YX6 (X=Br), the preparation method of which includes: In a nitrogen glove box, 7.03 g of LiBr (99.9% purity) and 8.87 g of YBr3 (99% purity) were weighed out according to a certain molar ratio and mixed to obtain a mixed raw material. The above mixed raw materials are placed into a ball mill jar, and φ10 zirconia balls are added at a ball-to-material ratio of 15:1. The ball mill jar is then sealed to obtain a sealed ball mill jar. The sealed ball mill jar was removed from the glove box and placed in a ball mill for ball milling to obtain the ball milled product, namely the precursor powder Li3YBr6. The performance of the prepared precursor was then tested. The ball mill speed was 200 rpm and the ball milling time was 4 h.

[0059] Example 3: Example 3 provides a halide solid electrolyte Li3YX6 (X=Br), the preparation method of which includes: In a nitrogen glove box, 7.03 g of LiBr (99.9% purity) and 8.87 g of YBr3 (99% purity) were weighed out according to a certain molar ratio and mixed to obtain a mixed raw material. The above mixed raw materials are placed into a ball mill jar, and φ10 zirconia balls are added at a ball-to-material ratio of 20:1. The ball mill jar is then sealed to obtain a sealed ball mill jar. The sealed ball mill jar was removed from the glove box and placed in a ball mill for ball milling to obtain the ball milled product, namely the precursor powder Li3YBr6. The performance of the prepared precursor was then tested. The ball mill speed was 200 rpm and the ball milling time was 4 h.

[0060] Example 4: Example 4 provides a halide solid electrolyte Li3YX6 (X=Br), the preparation method of which includes: In a nitrogen glove box, 7.03 g of LiBr (99.9% purity) and 8.87 g of YBr3 (99% purity) were weighed out according to a certain molar ratio and mixed to obtain a mixed raw material. The above mixed raw materials are placed into a ball mill jar, and φ10 zirconia balls are added at a ball-to-material ratio of 15:1. The ball mill jar is then sealed to obtain a sealed ball mill jar. The sealed ball mill jar was removed from the glove box and placed in a ball mill for ball milling to obtain the ball milled product, namely the precursor powder Li3YBr6. The performance of the prepared precursor was then tested. The ball mill speed was 200 rpm and the ball milling time was 6 h.

[0061] Example 5: Example 5 provides a halide solid electrolyte Li3YX6 (X=Br), the preparation method of which includes: In a nitrogen glove box, 7.03 g of LiBr (99.9% purity) and 8.87 g of YBr3 (99% purity) were weighed out according to a certain molar ratio and mixed to obtain a mixed raw material. The above mixed raw materials are placed into a ball mill jar, and φ10 zirconia balls are added at a ball-to-material ratio of 15:1. The ball mill jar is then sealed to obtain a sealed ball mill jar. The sealed ball mill jar was removed from the glove box and placed in a ball mill for ball milling to obtain the ball milled product, namely the precursor powder Li3YBr6. The performance of the prepared precursor was then tested. The ball mill speed was 200 rpm and the ball milling time was 8 h.

[0062] Example 6: Example 6 provides a halide solid electrolyte Li3YX6 (X=Br), the preparation method of which includes: In a nitrogen glove box, 7.03 g of LiBr (99.9% purity) and 8.87 g of YBr3 (99% purity) were weighed out according to a certain molar ratio and mixed to obtain a mixed raw material. The above mixed raw materials are placed into a ball mill jar, and φ10 zirconia balls are added at a ball-to-material ratio of 15:1. The ball mill jar is then sealed to obtain a sealed ball mill jar. The sealed ball mill jar was removed from the glove box and placed in a ball mill for ball milling to obtain the ball milled product, namely the precursor powder Li3YBr6. The performance of the prepared precursor was then tested. The ball mill speed was 200 rpm and the ball milling time was 10 h.

[0063] Example 7: Example 7 provides a halide solid electrolyte Li3YX6 (X=Br), the preparation method of which includes: In a nitrogen glove box, 7.03 g of LiBr (99.9% purity) and 8.87 g of YBr3 (99% purity) were weighed out according to a certain molar ratio and mixed to obtain a mixed raw material. The above mixed raw materials are placed into a ball mill jar, and φ10 zirconia balls are added at a ball-to-material ratio of 15:1. The ball mill jar is then sealed to obtain a sealed ball mill jar. The sealed ball mill jar was removed from the glove box and placed in a ball mill for ball milling to obtain the ball milled product, namely the precursor powder Li3YBr6. The performance of the prepared precursor was then tested. The ball mill speed was 150 rpm and the ball milling time was 8 h.

[0064] Example 8: Example 8 provides a halide solid electrolyte Li3YX6 (X=Br), the preparation method of which includes: In a nitrogen glove box, 7.03 g of LiBr (99.9% purity) and 8.87 g of YBr3 (99% purity) were weighed out according to a certain molar ratio and mixed to obtain a mixed raw material. The above mixed raw materials are placed into a ball mill jar, and φ10 zirconia balls are added at a ball-to-material ratio of 15:1. The ball mill jar is then sealed to obtain a sealed ball mill jar. The sealed ball mill jar was removed from the glove box and placed in a ball mill for ball milling to obtain the ball-milled product, namely the precursor powder Li3YBr6. The properties of the prepared precursor were then tested. The ball mill speed was 250 rpm, and the milling time was 8 h. Furthermore, XRD analysis was performed on the Li3YBr6 precursor powder, and its XRD pattern is shown below. Figure 4 As shown.

[0065] Example 9: Example 9 provides a halide solid electrolyte Li3YX6 (X=Br), the preparation method of which includes: In a nitrogen glove box, 7.03 g of LiBr (99.9% purity) and 8.87 g of YBr3 (99% purity) were weighed out according to a certain molar ratio and mixed to obtain a mixed raw material. The above mixed raw materials are placed into a ball mill jar, and φ10 zirconia balls are added at a ball-to-material ratio of 15:1. The ball mill jar is then sealed to obtain a sealed ball mill jar. The sealed ball mill jar was removed from the glove box and placed in a ball mill for ball milling to obtain the ball milled product, namely the precursor powder Li3YBr6; the ball mill speed was 250 rpm and the ball milling time was 8 h. Li3YBr6 was placed in a crucible and then transferred to a muffle furnace. The heating program was set, and the crucible was heated to 250°C at a heating rate of 1°C / min under an inert atmosphere. The temperature was held for 4 hours and then cooled to room temperature with the furnace. The cooled electrolyte block was removed from the muffle furnace, placed in a mortar and ground into powder. After passing through a 60-mesh sieve, Li3YBr6 solid electrolyte was obtained, and the performance of the prepared Li3YBr6 solid electrolyte was tested.

[0066] Example 10: Example 10 provides a halide solid electrolyte Li3YX6 (X=Br), the preparation method of which includes: In a nitrogen glove box, 7.03 g of LiBr (99.9% purity) and 8.87 g of YBr3 (99% purity) were weighed out according to a certain molar ratio and mixed to obtain a mixed raw material. The above mixed raw materials are placed into a ball mill jar, and φ10 zirconia balls are added at a ball-to-material ratio of 15:1. The ball mill jar is then sealed to obtain a sealed ball mill jar. The sealed ball mill jar was removed from the glove box and placed in a ball mill for ball milling to obtain the ball milled product, namely the precursor powder Li3YBr6; the ball mill speed was 250 rpm and the ball milling time was 8 h. Li3YBr6 was placed in a crucible and then transferred to a muffle furnace. The heating program was set, and the crucible was heated to 300℃ at a heating rate of 1℃ / min under an inert atmosphere. The temperature was held for 4 h, and then cooled to room temperature with the furnace. The cooled electrolyte block was removed from the muffle furnace, placed in a mortar and ground into powder. After passing through a 60-mesh sieve, Li3YBr6 solid electrolyte was obtained, and the performance of the prepared Li3YBr6 solid electrolyte was tested.

[0067] Example 11: Example 11 provides a halide solid electrolyte Li3YX6 (X=Br), the preparation method of which includes: In a nitrogen glove box, 7.03 g of LiBr (99.9% purity) and 8.87 g of YBr3 (99% purity) were weighed out according to a certain molar ratio and mixed to obtain a mixed raw material. The above mixed raw materials are placed into a ball mill jar, and φ10 zirconia balls are added at a ball-to-material ratio of 15:1. The ball mill jar is then sealed to obtain a sealed ball mill jar. The sealed ball mill jar was removed from the glove box and placed in a ball mill for ball milling to obtain the ball milled product, namely the precursor powder Li3YBr6; the ball mill speed was 250 rpm and the ball milling time was 8 h. Li3YBr6 was placed in a crucible and then transferred to a muffle furnace. The heating program was set, and the crucible was heated to 350°C at a heating rate of 1°C / min under an inert atmosphere. The temperature was held for 4 hours and then cooled to room temperature with the furnace. The cooled electrolyte block was removed from the muffle furnace, placed in a mortar and ground into powder. After passing through a 60-mesh sieve, Li3YBr6 solid electrolyte was obtained, and the performance of the prepared Li3YBr6 solid electrolyte was tested.

[0068] Example 12: Example 12 provides a halide solid electrolyte Li3YX6 (X=Br), the preparation method of which includes: In a nitrogen glove box, 7.03 g of LiBr (99.9% purity) and 8.87 g of YBr3 (99% purity) were weighed out according to a certain molar ratio and mixed to obtain a mixed raw material. The above mixed raw materials are placed into a ball mill jar, and φ10 zirconia balls are added at a ball-to-material ratio of 15:1. The ball mill jar is then sealed to obtain a sealed ball mill jar. The sealed ball mill jar was removed from the glove box and placed in a ball mill for ball milling to obtain the ball milled product, namely the precursor powder Li3YBr6; the ball mill speed was 250 rpm and the ball milling time was 8 h. Li3YBr6 was placed in a crucible and then transferred to a muffle furnace. The heating program was set, and the crucible was heated to 400℃ at a heating rate of 1℃ / min under an inert atmosphere. The temperature was held for 4 h, and then cooled to room temperature with the furnace. The cooled electrolyte block was removed from the muffle furnace, placed in a mortar and ground into powder. After passing through a 60-mesh sieve, Li3YBr6 solid electrolyte was obtained, and the performance of the prepared Li3YBr6 solid electrolyte was tested.

[0069] Example 13: Example 13 provides a halide solid electrolyte Li3YX6 (X=Br), the preparation method of which includes: In a nitrogen glove box, 7.03 g of LiBr (99.9% purity) and 8.87 g of YBr3 (99% purity) were weighed out according to a certain molar ratio and mixed to obtain a mixed raw material. The above mixed raw materials are placed into a ball mill jar, and φ10 zirconia balls are added at a ball-to-material ratio of 15:1. The ball mill jar is then sealed to obtain a sealed ball mill jar. The sealed ball mill jar was removed from the glove box and placed in a ball mill for ball milling to obtain the ball milled product, namely the precursor powder Li3YBr6; the ball mill speed was 250 rpm and the ball milling time was 8 h. Li3YBr6 was placed in a crucible and then transferred to a muffle furnace. The heating program was set, and the crucible was heated to 350°C at a heating rate of 1°C / min under an inert atmosphere. The temperature was held for 6 hours and then cooled to room temperature with the furnace. The cooled electrolyte block was removed from the muffle furnace and ground into powder in a mortar. After passing through a 60-mesh sieve, Li3YBr6 solid electrolyte was obtained, and its performance was tested. Furthermore, XRD analysis was performed on the prepared Li3YBr6, and its XRD pattern is shown below. Figure 5 As shown.

[0070] Example 14: Example 14 provides a halide solid electrolyte Li3YX6 (X=Br), the preparation method of which includes: In a nitrogen glove box, 7.03 g of LiBr (99.9% purity) and 8.87 g of YBr3 (99% purity) were weighed out according to a certain molar ratio and mixed to obtain a mixed raw material. The above mixed raw materials are placed into a ball mill jar, and φ10 zirconia balls are added at a ball-to-material ratio of 15:1. The ball mill jar is then sealed to obtain a sealed ball mill jar. The sealed ball mill jar was removed from the glove box and placed in a ball mill for ball milling to obtain the ball milled product, namely the precursor powder Li3YBr6; the ball mill speed was 250 rpm and the ball milling time was 8 h. Li3YBr6 was placed in a crucible and then transferred to a muffle furnace. The heating program was set, and the crucible was heated to 350°C at a heating rate of 1°C / min under an inert atmosphere. The temperature was held for 8 hours and then cooled to room temperature with the furnace. The cooled electrolyte block was removed from the muffle furnace, placed in a mortar and ground into powder. After passing through a 60-mesh sieve, Li3YBr6 solid electrolyte was obtained, and the performance of the prepared Li3YBr6 solid electrolyte was tested.

[0071] Comparative Example 1: Comparative Example 1 provides a halide solid electrolyte Li3YX6 (X=Br), the preparation method of which includes: In a nitrogen glove box, 7.03 g of LiBr (99.9% purity) and 8.87 g of YBr3 (99% purity) were weighed out according to a certain molar ratio and mixed thoroughly in a mortar for 30 min. The mixed powder was placed in a crucible and then transferred to a muffle furnace. The heating program was set, and the powder was heated to 550°C at a heating rate of 1°C / min under an inert atmosphere. The temperature was held for 16 hours and then cooled to room temperature with the furnace. The cooled electrolyte block was removed from the muffle furnace and ground into powder in a mortar. After passing through a 60-mesh sieve, Li3YBr6 solid electrolyte was obtained. The performance of the prepared Li3YBr6 solid electrolyte was then tested. Furthermore, XRD analysis was performed on the above-mentioned Li3YBr6 solid electrolyte, and its XRD pattern is shown below. Figure 6 As shown.

[0072] In the embodiments of this application, the difference between Embodiment 2 and Embodiment 1 is that the ball-to-material ratio in Embodiment 2 is 15:1; the difference between Embodiment 3 and Embodiment 1 is that the ball-to-material ratio in Embodiment 3 is 20:1; the difference between Embodiment 5 and Embodiment 4 is that the ball milling time in Embodiment 5 is 8 h; the difference between Embodiment 6 and Embodiment 4 is that the ball milling time in Embodiment 6 is 10 h; the difference between Embodiment 8 and Embodiment 7 is that the ball milling speed in Embodiment 8 is 250 rpm; the difference between Embodiment 10 and Embodiment 9 is that the heat treatment temperature in Embodiment 10 is 300℃; the difference between Embodiment 11 and Embodiment 9 is that the heat treatment temperature in Embodiment 11 is 350℃; the difference between Embodiment 12 and Embodiment 9 is that the heat treatment temperature in Embodiment 12 is 400℃; and the difference between Embodiment 14 and Embodiment 13 is that the heat treatment time in Embodiment 14 is 8 h.

[0073] In the embodiments of this application, Figure 4 The middle part is the precursor phase after ball milling in Example 8, from... Figure 4 It can be seen that using a ball-to-material ratio of 15:1 and ball milling at 250 rpm for 8 hours, the resulting precursor is a pure phase. Figure 5 The image shows the X-ray diffraction (XRD) pattern of the Li3YBr6 solid electrolyte prepared in Example 13. Figure 5 As can be seen, the prepared halide solid electrolyte is a pure phase. Figure 6 The X-ray diffraction pattern of the product obtained after heat treatment in Comparative Example 1 is shown below. Figure 6 The XRD pattern shows a high number of impurity peaks. The horizontal axis of the XRD pattern represents the diffraction angle 2θ, indicating the angle between the X-ray diffracted beam and the incident beam, while the vertical axis represents the diffraction intensity. The horizontal and vertical axes of the electrochemical impedance spectroscopy correspond to the real part Z' and imaginary part -Z'' (or Z'') of the impedance, respectively, and are used to characterize the resistance, capacitance, and other properties of the electrochemical system.

[0074] In this application embodiment, the particle size and ionic conductivity of the sulfide solid electrolytes prepared in the above embodiments and comparative examples were tested. The ionic conductivity was calculated using the conductivity calculation formula, as shown below:

[0075] Where L is the sample thickness, R is the total impedance, and S is the effective contact area between the sample and the electrode. The total ionic conductivity is calculated. Table 1 is a comparison table of the ionic conductivity of the sulfide solid electrolytes prepared in each example and comparative example.

[0076] Table 1. Summary of experimental parameters and performance test results in each embodiment and comparative example.

[0077] In the embodiments of this application, Figure 7 The image shows the ionic conductivity of the precursor after ball milling in Example 8. Figure 7 It can be seen from this that the precursor ion conductivity is 0.316 mS / cm. Figure 8 To utilize the ionic conductivity of the heat-treated electrolyte in Example 13, from Figure 8 It can be seen from this that its ionic conductivity is 1.97 mS / cm. Figure 9 The image shows an electron micrograph of the electrolyte after heat treatment according to Example 13. Figure 9 It can be seen that the electrolyte particles of the halide solid electrolyte are uniform in size, with a narrow and controllable particle size range. The particle size of the electrolyte particles is between 100 nm and 200 nm. This indicates that the combination of mechanical ball milling and heat treatment processes in this application results in halide solid electrolytes with uniform powder particle size and morphology, and high ionic conductivity.

[0078] As can be seen from the embodiments provided in this application above, this application mixes a lithium-containing compound, a yttrium-containing compound, and a halogen compound to obtain a mixed raw material; the mixed raw material is ball-milled to obtain a ball-milled product; the ball-milled product is transferred to a muffle furnace and heated to a preset temperature at a preset heating rate under an inert gas atmosphere, and held at the preset temperature for a preset holding time, and then cooled to room temperature to obtain an initial product; the initial product is ground to obtain a halide solid electrolyte; the general chemical formula of the halide solid electrolyte is Li3YX6, where X is one of Cl, Br, I, and F. This application combines mechanical ball milling with heat treatment to effectively reduce the reaction temperature of Li3YX6, preventing the decomposition and volatilization of halogen compounds. The resulting halide solid electrolyte has uniform particle size and morphology, significantly improving its air stability. By controlling the ball milling and heat treatment process parameters, the electrolyte morphology can be regulated. Furthermore, the preparation method provided in this application is simpler, more convenient to operate, and lower in cost. The resulting electrolyte product has high purity, high ionic conductivity, good compatibility with the positive electrode, and excellent electrochemical performance.

[0079] The above description is only a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing a halide solid electrolyte, characterized in that, The method includes: A mixed raw material is obtained by mixing a lithium-containing compound, a yttrium-containing compound, and a halogen compound. The mixed raw materials are ball-milled to obtain the ball-milled product; The ball-milled product is transferred to a muffle furnace and heated to a preset temperature at a preset heating rate under an inert gas atmosphere. The product is then held at the preset temperature for a preset holding time and subsequently cooled to room temperature to obtain the initial product. The initial product is ground to obtain the halide solid electrolyte; the chemical formula of the halide solid electrolyte is Li3YX6, where X is one of Cl, Br, I, and F.

2. The method according to claim 1, characterized in that, The preset heating rate is 1℃ / min-5℃ / min; The preset temperature is 200℃-600℃; The preset heat preservation time is 2 h-10 h.

3. The method according to claim 1, characterized in that, The process of mixing a lithium-containing compound, a yttrium-containing compound, and a halogen compound to obtain a mixed raw material includes: The lithium-containing compound, the yttrium-containing compound, and the halogen compound were placed in a glove box, and the lithium-containing compound, the yttrium-containing compound, and the halogen compound were weighed according to a preset molar ratio. The weighed raw materials are mixed to obtain the mixed raw materials.

4. The method according to claim 3, characterized in that, The process of ball milling the mixed raw materials to obtain the ball-milled product includes: The mixed raw materials are placed in a ball mill jar, and zirconia balls are added. The ball mill jar is then sealed to obtain a sealed ball mill jar. The sealed ball mill jar is transferred from the glove box to the ball mill to ball mill the mixed raw materials and obtain the ball milled product.

5. The method according to claim 4, characterized in that, The lithium-containing compound is one or more of LiH, Li2CO3, LiCl, LiBr, LiI, LiF, LiS, and LiSe; The yttrium-containing compound is one or more of YCl3, YBr3, YI3, and Y2(CO3)3; The halogen compound is one or more of LiCl, LiBr, LiI, and LiF.

6. The method according to claim 5, characterized in that, The diameter of the zirconia spheres is 1 mm to 10 mm; The ratio of the zirconium oxide spheres to the mixed raw materials is in the range of 5:1 to 20:1; During the ball milling process, the rotation speed of the ball mill is 50 rpm-250 rpm, and the milling time is 2 h-12 h.

7. The method according to claim 1, characterized in that, The step of grinding the initial product to obtain the halide solid electrolyte includes: The initial product is ground to obtain a ground powder; The ground powder is sieved to obtain the halide solid electrolyte.

8. The method according to claim 7, characterized in that, The sieve size during the sieving process is 40-60 mesh. The particle size of the electrolyte particles in the halide solid electrolyte is 100 nm-200 nm.

9. The method according to claim 1, characterized in that, The halide solid electrolyte has the general chemical formula Li3YBr6. The ball-milled product is transferred to a muffle furnace and heated to a preset temperature at a preset heating rate under an inert gas atmosphere. It is then held at the preset temperature for a preset holding time, and subsequently cooled to room temperature to obtain the initial product, comprising: The ball-milled product is transferred to a crucible, and the crucible is placed in the muffle furnace and heated to 250°C-450°C at a heating rate of 1°C / min-2°C / min under the inert gas atmosphere. The initial product was obtained by holding the product at 250℃-450℃ for 4-8 hours and then cooling it to room temperature.

10. A halide solid electrolyte, characterized in that, The halide solid electrolyte is prepared using the method for preparing halide solid electrolyte as described in any one of claims 1-9.

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