Solid electrolyte materials, their preparation methods, and batteries

Abstract

The present application provides a solid electrolyte material, a preparation method thereof, and a battery. The solid electrolyte material is amorphous, and the chemical formula of the solid electrolyte material is xLi3N·yLi2O·zLiF·TaCl5, 0.1≤x≤0.6, 0.1≤y≤2, 0.1≤z≤2. By introducing F, O, and N elements into the solid electrolyte, the electrolyte oxidation potential of the halide is increased and the air stability is improved. In addition, by controlling the ratio of different components, the electrolyte material is made into an amorphous structure. Since the amorphous structure has a long-range disordered state and a large number of defects, these defects create good conditions for ion transport, thereby improving the conductivity of the solid electrolyte.

Description

Technical Field

[0001] The present application relates to the field of batteries, and in particular to a solid electrolyte material, a preparation method thereof, and a battery. Background Art

[0002] Solid-state electrolytes are a key component of solid-state lithium-ion batteries. Using solid materials instead of traditional liquid electrolytes fundamentally eliminates the safety risks associated with liquid electrolytes, such as flammability. Solid-state electrolytes not only improve battery safety but also simplify manufacturing processes, increasing battery energy density, reliability, and design freedom.

[0003] The current mainstream solid electrolyte systems are mainly divided into three systems: oxides, sulfides and halides. Although oxide electrolytes have high oxidation potentials, they have low ionic conductivity and high rigidity, resulting in high contact impedance, which affects battery performance. Sulfide electrolytes have high ionic conductivity and good ductility, but they have low oxidation potentials, poor air stability, and are easy to react with moisture to generate harmful gases, and the preparation environment requirements are strict. Among the halide electrolytes, LiMOCl4 (M is Ta or Nb), LiTaCl5N (N= F - or O 2- ) and Li₃InCl₆ are among the solid electrolyte materials receiving significant attention. Their oxidation potentials are higher than those of sulfides, theoretically making them more compatible with positive electrodes. However, their ionic conductivity is modest, and they suffer from poor air stability. When exposed to air, they react with moisture to produce HCl gas, severely degrading performance and affecting the battery's high-rate and long-cycle performance.

[0004] Therefore, how to improve the air stability and ionic conductivity of halide electrolytes is an urgent problem to be solved. Summary of the Invention

[0005] The present application provides a solid electrolyte material, a preparation method thereof, and a battery, which are used to improve the air stability and ionic conductivity of halide electrolytes.

[0006] In a first aspect, the present application provides a solid electrolyte material, which is amorphous and has a chemical formula of xLi3N·yLi2O·zLiF·TaCl5, 0.1≤x≤0.6, 0.1≤y≤2, and 0.1≤z≤2.

[0007] Furthermore, 0.3≤x≤0.5, 0.5≤y≤1, 1≤z≤2.

[0008] Furthermore, the D50 particle size of the solid electrolyte material is 2-6 μm.

[0009] Furthermore, the D90 particle size of the solid electrolyte material is 10-20 μm.

[0010] In a second aspect, the present application provides a method for preparing a solid electrolyte material, the method being used to prepare the solid electrolyte material according to any one of the first aspects, the method being carried out under an inert gas atmosphere, comprising:

[0011] The four raw materials Li3N, Li2O, LiF and TaCl5 were pulverized and refined respectively;

[0012] The powdered and refined materials are subjected to ball milling and mixing according to a preset molar ratio to obtain a precursor;

[0013] The precursor is transferred to a muffle furnace for heat treatment to obtain the solid electrolyte material, wherein the heat treatment temperature is 250-450°C.

[0014] Furthermore, the heat treatment time is 2-8 hours.

[0015] Furthermore, the preparation method further comprises:

[0016] The solid electrolyte material is ground and passed through a sieve to obtain a refined solid electrolyte material.

[0017] Furthermore, the ball-to-material ratio in the ball milling mixing process is (20-30):1;

[0018] And / or, the ball milling speed is 150-250 rpm, the turning speed is 1-8 rpm, and the ball milling time is 4-8 h.

[0019] Furthermore, the powdering speed of the powdering and refining treatment is 20000-30000 r / min, and the powdering time is 2-4 minutes.

[0020] In a third aspect, the present application provides a battery comprising the solid electrolyte material described in any one of the first aspects, or the solid electrolyte material prepared by the preparation method of the solid electrolyte material described in any one of the second aspects.

[0021] The present application provides a solid electrolyte material, a preparation method thereof, and a battery. The solid electrolyte material is amorphous, and the chemical formula of the solid electrolyte material is xLi3N·yLi2O·zLiF·TaCl5, 0.1≤x≤0.6, 0.1≤y≤2, 0.1≤z≤2. By introducing F, O, and N elements into the solid electrolyte, the electrolyte oxidation potential of the halide is increased and the air stability is improved. In addition, by controlling the ratio of different components, the electrolyte material is made into an amorphous structure. Since the amorphous structure has a long-range disordered state and a large number of defects, these defects create good conditions for ion transport, thereby improving conductivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0023] Figure 1 The XRD patterns of Examples 1-7 provided in this application;

[0024] Figure 2 XRD diagrams of Examples 8-9 and Comparative Examples 1-3 provided in this application;

[0025] Figure 3 XRD diagrams of Comparative Examples 4-6 provided in this application;

[0026] Figure 4 This is a SEM image of the solid electrolyte and positive electrode material mixed provided in this application. DETAILED DESCRIPTION

[0027] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numbers in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples consistent with certain aspects of the present application, as detailed in the appended claims.

[0028] Traditional lithium-ion batteries use organic solvents as their electrolyte, many of which are flammable. When the battery is exposed to short circuits, overcharging, or external impact, the electrolyte can leak, causing fire or explosion, potentially leading to safety incidents. Solid-state electrolytes, on the other hand, are less flammable than liquid electrolytes and possess greater thermal stability, remaining stable under high temperatures and extreme conditions, offering greater safety advantages. They also simplify the manufacturing and packaging process, improving the battery's energy density, reliability, and design freedom.

[0029] Therefore, strong requirements are placed on the properties of solid electrolytes such as high ionic conductivity, high potential stability, and high air stability.

[0030] Among inorganic solid electrolyte materials, halide electrolytes such as LiMOCl4 (M is Ta or Nb), LiTaCl5N (N=F - or O 2-), Li3InCl6, etc. are several types of solid electrolyte materials that have recently attracted attention. Their oxidation potentials are higher than those of sulfides, and theoretically they are more compatible with the positive electrode. However, they still have the following problems: poor air stability, easy to react with moisture in the air to generate HCl gas when exposed to air, and serious performance degradation; Young's modulus is higher than that of sulfide, that is, hardness is greater, resulting in poor processability and difficulty in evenly mixing with the positive electrode to form a dense positive electrode coating layer, which seriously affects the high rate and long cycle performance of the battery.

[0031] In view of the above problems, this application proposes a solid electrolyte, the design idea of which is to introduce F, O, and N elements into the halide electrolyte for doping modification to increase the electrolyte oxidation potential of the halide and improve air stability. In addition, the designed electrolyte material is made into an amorphous structure. Since the amorphous structure has a long-range disordered state and a large number of defects, these defects create good conditions for ion transport, thereby improving conductivity. Through the above design ideas, the prepared solid electrolyte has good conductivity, air stability and high oxidation potential.

[0032] In a first aspect, the present application provides a solid electrolyte material having an amorphous structure and a chemical formula of xLi3N·yLi2O·zLiF·TaCl5, 0.1≤x≤0.6, 0.1≤y≤2, and 0.1≤z≤2.

[0033] When lithium fluoride is added to the electrolyte, the high electronegativity of the fluorine atom helps improve the stability of the electrolyte and reduce the risk of electrolyte decomposition under high voltage. In addition, fluoride has a high redox potential. Therefore, the addition of lithium fluoride increases the oxidation potential of the electrolyte, enhancing its contact stability with the positive electrode material and improving battery performance.

[0034] The oxygen in Li2O (lithium oxide) enhances the electrolyte's air stability. Compared to other oxygen-free substances, it is more resistant to reactions with moisture and oxygen in the air, thereby reducing the risk of hydrolysis or oxidative corrosion. Li3N (lithium nitride) itself has strong resistance to hydrolysis and low reactivity with oxygen, making it relatively stable at room temperature. Therefore, the addition of Li3N improves its air stability and helps improve the safety and stability of the battery during use. Electrolytes with high air stability have lower environmental requirements during manufacturing, thereby reducing manufacturing costs and facilitating large-scale mass production.

[0035] Preparing solid electrolyte materials into an amorphous state is a key measure to improve conductivity. Because the structure of amorphous solid electrolytes has a long-range disorder state and a large number of defects, these defects create good conditions for ion transport, thereby improving conductivity.

[0036] Secondly, due to its grain-free nature, amorphous solid electrolytes can form more uniform contact with electrode materials, reducing poor contact and interfacial impedance, thereby enhancing the integrity of solid-solid contact. This contact improves the transmission efficiency of electrons and ions within the battery, which is especially important for high-performance cathode materials. The grain-free nature also makes the lithium ion conduction path more uniform. Grain boundaries usually cause local interruptions or obstacles to ion conduction in crystalline electrolytes because the migration speed of ions at grain boundaries is slow and irreversible reactions are prone to occur. Due to the randomness of the atomic arrangement of amorphous electrolytes, there is no such local obstruction. Lithium ions can migrate quickly in a more uniform structure, improving the battery's charge and discharge efficiency and cycle performance.

[0037] In addition, amorphous solid electrolytes have advantages such as greater flexibility, ease of fabrication, low grain boundaries, wider compositional variation, and isotropic ion conduction. Therefore, they have higher processability, are easier to mix evenly with the positive electrode, and can form a good coating on the surface of the positive electrode particles, which is conducive to achieving high rate and long cycle performance of the battery.

[0038] In order to ensure the amorphous characteristics and electrolyte performance of the solid electrolyte, it is necessary to regulate the proportions of the four materials Li3N, Li2O, LiF, and TaCl5.

[0039] Based on one mole fraction of TaCl5, the mole fraction x of Li3N is 0.1≤x≤0.6. For example, x can be selected from any value of 0.1, 0.15, 0.2, 0.25, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, or a range consisting of any two of the above values.

[0040] Based on one mole fraction of TaCl5, the mole fraction y of Li2O is 0.1≤y≤2. Exemplarily, x can be selected from any one of 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, and 2.0, or a range consisting of any two of the above values.

[0041] Based on one mole fraction of TaCl5, the mole fraction z of LiF is 0.1≤z≤2. Exemplarily, x can be selected from any one of 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, and 2.0, or a range consisting of any two of the above values.

[0042] Under the above-mentioned component ratios, the prepared solid electrolyte material is an amorphous solid electrolyte. When the proportion of Li2O or LiF components is too high, it is difficult to destroy the crystalline structure, which reduces the material performance.

[0043] Preferably, in xLi3N·yLi2O·zLiF·TaCl5, 0.3≤x≤0.5, 0.5≤y≤1, and 1≤z≤2. With the above ratio, the amorphous solid electrolyte prepared has better battery performance.

[0044] In some embodiments, the D50 particle size of the solid electrolyte material is 2-6 μm. Specifically, the D50 particle size of the solid electrolyte material can be 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, or a range consisting of any two of the above values.

[0045] In some embodiments, the D90 particle size of the solid electrolyte material is 10-20 μm. Specifically, the D90 particle size of the solid electrolyte material can be 10 μm, 12 μm, 14 μm, 15 μm, 16 μm, 18 μm, 19 μm, 20 μm, or a range consisting of any two of the above values.

[0046] A second aspect of the present application provides a method for preparing a solid electrolyte material, which is used to prepare any solid electrolyte material according to the first aspect. Each step of the preparation method is performed under an inert gas atmosphere, comprising:

[0047] Step 1: Powder and refine the four raw materials Li3N, Li2O, LiF and TaCl5 respectively.

[0048] Step 2: The pulverized and refined material is subjected to ball milling and mixing according to a preset molar ratio to obtain a precursor.

[0049] Step 3: Under an inert gas atmosphere, transfer the precursor to a muffle furnace for heat treatment to obtain a solid electrolyte material, wherein the heat treatment temperature is 250-450°C.

[0050] In some embodiments, after step 3, the preliminary solid electrolyte material is ground and sieved under an inert gas atmosphere to obtain a refined electrolyte material, wherein the particle size D50 of the refined electrolyte material is 2-6 μm, and / or the particle size D90 is 10-20 μm.

[0051] In a specific implementation, the sieve is 500 mesh.

[0052] In some embodiments, in step 2, the ball milling and mixing process is performed using an omnidirectional planetary ball mill to achieve all-around ball milling and mixing without dead angles. Unlike conventional vertical planetary ball mills, the omnidirectional planetary ball mill operates while the planetary main disc rotates 360° or at any angle while the planetary tank rotates, allowing the material to fully participate in the grinding and mixing, thereby reducing the phenomenon of material sinking to the bottom and achieving the goal of mixing without dead angles.

[0053] In some embodiments, the ball-to-material ratio in the ball milling process is (20-30): 1. Specifically, the ball-to-material ratio can be 20:1, 22:1, 24:1, 26:1, 28:1, 30:1, or a range consisting of any two of the above values.

[0054] In some embodiments, the ball milling speed is 150-250 rpm. Specifically, the ball milling speed can be 150 rpm, 175 rpm, 200 rpm, 225 rpm, 250 rpm, or a range consisting of any two of the above values.

[0055] In some embodiments, during the ball milling process, the ball turnover speed is 1-8 rpm. Specifically, the turnover speed can be 1 rpm, 2 rpm, 3 rpm, 4 rpm, 5 rpm, 6 rpm, 7 rpm, 8 rpm, or a range consisting of any two of the above values.

[0056] In some embodiments, during the ball milling mixing process, the ball milling time is 4-8 hours. Specifically, the ball milling time can be 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, or a range consisting of any two of the above values.

[0057] In some embodiments, the heat treatment time in step 3 is 2-8 hours. Specifically, the heat treatment time can be 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, or a range consisting of any two of the above values.

[0058] In some embodiments, the powdering speed of the powdering and refining process is 20,000 r / min-30,000 r / min. Specifically, the powdering speed can be 20,000 r / min, 22,000 r / min, 24,000 r / min, 26,000 r / min, 28,000 r / min, 30,000 r / min, or a range consisting of any two of the above values.

[0059] In some embodiments, the powdering time of the powdering and refining process is 2-4 minutes. Specifically, the powdering time can be 2 minutes, 2.4 minutes, 2.8 minutes, 3.0 minutes, 3.4 minutes, 3.8 minutes, 4 minutes, or a range consisting of any two of the above values.

[0060] In some embodiments, the preset molar ratio of step 2 is the same as the description of regulating the proportions of the four materials Li3N, Li2O, LiF, and TaCl5 in the first aspect above, and will not be repeated here.

[0061] A third aspect of the present application provides a battery, which includes any solid electrolyte material according to the first aspect, or a solid electrolyte material prepared by the preparation method of any solid electrolyte material according to the second aspect.

[0062] The present application does not impose any particular limitation on the method for preparing the battery, and the battery can be prepared by referring to conventional methods in the art.

[0063] The present application also provides an electronic device including the battery described above. The present application does not specifically limit the electronic device, and the electronic device may be any electrical device including the battery, including but not limited to mobile phones, laptops, electric bicycles, electric cars, electric toys, energy storage devices, etc.

[0064] The solid electrolyte provided by the present invention, its preparation method and application will be further described in detail below through specific examples.

[0065] Unless otherwise specified, the reagents, materials, and instruments used in the following examples are conventional reagents, conventional materials, and conventional instruments in the art and can be obtained commercially. The reagents involved can also be synthesized by conventional methods in the art.

[0066] Example 1

[0067] The preparation method of the target electrolyte material "0.3Li3N·0.5Li2O·LiF·TaCl5" comprises the following steps:

[0068] 1) Under the protection of argon atmosphere, the four raw materials were pulverized and refined respectively. A 200g type pulverizer was used, with a processing capacity of 100g each, a pulverizing speed of 25000r / min, and a pulverizing time of 3h. After the pulverization, 100g of each of the four raw materials was obtained.

[0069] 2) Under argon atmosphere, weigh Li3N, Li2O, LiF and TaCl5 raw materials in a molar ratio of 0.3 mol: 0.5 mol: 1 mol: 1 mol and put them into a ball mill. After sealing well, use an omnidirectional planetary ball mill to mix the materials. The ball-to-material ratio is 25:1, the ball milling speed is 200 rpm, the turnover speed is 2 rpm, and the ball milling time is 6 h to obtain the electrolyte precursor.

[0070] 3) Under the protection of argon atmosphere, the precursor was transferred to a muffle furnace for heat treatment. A sealed firing method was adopted, i.e., a quartz crucible was inside and an aluminum-titanium alloy sealed can was outside. The heat treatment temperature was 300°C, the temperature rise rate was 1°C / min, and the holding time was 4h. After natural cooling, the preliminary finished electrolyte was obtained.

[0071] 4) Finally, grinding and screening: the preliminary finished product is ground and passed through a 500-mesh sieve to obtain an electrolyte product with a particle size D50 of approximately 5 μm and D90 of approximately 15 μm.

[0072] In Examples 2 to 10, only the molar ratios of the four raw materials were changed. The process flow was the same as that of Example 1. The specific formulation information is shown in Table 1.

[0073] Comparative Example 1

[0074] Only Li3N and TaCl5 raw materials were used for electrolyte preparation. Specific information is shown in Table 1.

[0075] Comparative Example 2

[0076] Only Li2O and TaCl5 raw materials were used for electrolyte preparation. The specific information is shown in Table 1.

[0077] Comparative Example 3

[0078] Only LiF and TaCl5 raw materials were used for electrolyte preparation. Specific information is shown in Table 1.

[0079] Comparative Example 4

[0080] Based on the process flow of Example 1, the raw material formula is 0.7Li3N·0.5Li2O·LiF·TaCl5 to prepare a crystalline solid electrolyte.

[0081] Comparative Example 5

[0082] Based on the process flow of Example 1, the raw material formula is 0.3Li3N·2.1Li2O·LiF·TaCl5 to prepare a crystalline solid electrolyte.

[0083] Comparative Example 6

[0084] Based on the process flow of Example 1, the raw material formula is 0.3Li3N·0.5Li2O·2.1LiF·TaCl5 to prepare a crystalline solid electrolyte.

[0085] Table 1. Electrolyte composition information

[0086]

[0087] Test Case

[0088] Ionic conductivity test: Weigh 100mg of electrolyte powder, place it in an insulating sleeve with an inner diameter of 10mm, press it at a pressure of 300MPa, and perform an AC impedance spectrum test to measure the impedance value of the electrolyte material. Then, perform a thickness test on the pressurized sheet electrolyte. Based on the sheet impedance value, thickness value and area, the ionic conductivity of the electrolyte material is calculated using the formula σ=d / (R×S), where σ is the ionic conductivity in s / cm; d is the sheet thickness in cm; R is the impedance value in Ω; and S is the sheet area in cm. 2 The test results are shown in Table 2.

[0089] Air Stability Test: After the ionic conductivity test of the same batch of electrolyte was completed as described above, a 100mg sample of electrolyte powder was taken and placed in an environment with a temperature of 25±3°C and a dew point of ≤-55°C for 6 hours. After the idling period, the electrolyte ionic conductivity was retested and the ionic conductivity retention rate was calculated. If the ionic conductivity retention rate is ≥95%, the electrolyte has high air stability. The test results are shown in Table 2.

[0090] Target electrolyte voltage window test: The target electrolyte and conductive carbon powder were weighed at a weight ratio of 70:30 and ground evenly using an agate mortar. In an insulating outer cylinder with a diameter of 10 mm, 20 mg of the target electrolyte-conductive carbon powder mixture, 20 mg of Li 5.4 PS 4.4 Cl 1.6 The electrolyte is stacked. It is press-formed at a pressure of 360MPa. 5.4 PS 4.4 Cl 1.6 A lithium foil was laminated side-by-side and press-formed at a pressure of 100 MPa. Stainless steel current collectors were placed above and below the laminate, with leads attached to the collectors. Linear sweep voltammetry was performed over a 2-5 V range at a scan rate of 0.1 mV / s. A tangent to the oxidation peak of the test curve was drawn, and the intersection with the abscissa indicated the oxidation potential of the material. The test results are shown in Table 2.

[0091] Battery test: In an argon glove box, the target electrolyte, the positive electrode active material Li (Ni 0.8 Co 0.1 Mn 0.1 )O2(NCM811) were weighed at a weight ratio of 20:80. They were ground evenly using an agate mortar to prepare a composite positive electrode material. In an insulating outer cylinder with a diameter of 10 mm, 14 mg of the above composite positive electrode material, 70 mg of Li 5.4 PS 4.4 Cl 1.6The electrolyte is stacked. It is press-formed at a pressure of 360MPa to obtain a positive electrode and a solid electrolyte layer. Next, a piece of aluminum foil is stacked on the positive electrode side, thereby forming a current collector on the positive electrode side. Then, on the opposite side of the solid electrolyte layer in contact with the positive electrode, an indium sheet with a thickness of 200μm and a diameter of 10mm is placed as a negative electrode material. It is press-formed at a pressure of 80MPa to produce a stack consisting of a positive electrode, a solid electrolyte layer and a negative electrode. Then, stainless steel current collectors are arranged above and below the stack, and current collector leads are attached to the current collectors. The assembled solid-state battery was subjected to a cycle performance test under the following test conditions: current density of 1C and voltage range of 2.7-4.3V (Li+ / Li). The test is shown in Table 2.

[0092] Table 2. Electrolyte performance test and air stability evaluation

[0093]

[0094] Combining the data in Table 1 and Table 2, it can be seen from Examples 1 to 10 that the best effects are achieved when the doping amounts of Li3N, Li2O, and LiF are 0.4, 0.7, and 1.5, respectively. At this time, the target electrolyte (i.e., Example 6) has the highest ionic conductivity, the highest oxidation potential, and the best battery performance and air stability. Specifically, the target electrolyte oxidation potential reaches a maximum value of 4.52 V, the ionic conductivity reaches a maximum value of 6.8 mS / cm, the battery performance is optimal (initial efficiency 95.2%, first-week discharge capacity 210.8 mAh / g, 200-week cycle capacity retention rate 98.5%), and the air stability reaches a maximum value of 98.5%.

[0095] By comparing the data of Examples 1 to 3 with those of the embodiments, it can be seen that when a single material such as Li3N, Li2O or LiF is doped, although the target electrolyte after doping has certain properties, and some properties are even better than those of some embodiments, the performance is still worse than that of the electrolyte doped with three materials at the same time.

[0096] Comparing the data from Comparative Example 4 with Example 1 shows that when the Li3N component is in excess (x greater than 0.6), the ionic conductivity decreases significantly. Comparing the data from Comparative Example 5 with Example 1 shows that when the Li2O component is in excess (y greater than 2), the ionic conductivity decreases significantly. Comparing the data from Comparative Example 6 with Example 1 shows that when the LiF component is in excess (x greater than 2), the ionic conductivity decreases significantly.

[0097] The reason why the performance of Comparative Examples 4-6 is lower than that of Example 1 is that a crystalline phase is formed in the material, resulting in a decrease in ionic conductivity. Figure 1 、 Figure 2 and Figure 3 The XRD test can further prove this explanation. Figure 3 The XRD patterns of Comparative Examples 4-6 all show peak generation, indicating that a crystalline phase is generated in the electrolyte materials of Comparative Examples 4-6, while the XRD diagrams of Examples 1-10 all show an amorphous phase without obvious peaks. A small peak also appears at around 24 degrees in Comparative Example 1-3, indicating the presence of a crystalline phase. Due to the long-range disordered state of the amorphous structure, there are a large number of defects, which create good conditions for ion transport, thereby improving electrical conductivity. In addition, amorphous electrolytes have the advantages of being softer, easier to manufacture, having low grain boundaries, a wider range of composition changes, and isotropic ion conduction, so the target electrolyte has higher workability, is easier to mix evenly with the positive electrode, and forms a good coating layer on the surface of the positive electrode particles.

[0098] To further verify this conclusion, the amorphous halide electrolyte of Example 6 of the present invention and the commonly used crystalline Li3InCl6 halide electrolyte were mixed with the same positive electrode material (nickel cobalt manganese, referred to as NCM) to keep the mixing process consistent. After the mixing was completed, SEM tests were performed on them respectively. If the coating effect of the bare NCM surface is poor, it means that its surface is exposed to the outside and is easily affected by the environment, such as oxidation, corrosion, etc. Figure 4 Under the same resolution rate conditions, it can be clearly seen that the halide electrolyte of Example 6 of the present invention is more uniformly mixed with the positive electrode than the Li3InCl6 electrolyte, and can form a more comprehensive, dense and uniform coating layer on the positive electrode surface, which is more conducive to the battery rate and cycle performance.

[0099] Finally, it should be noted that while the above embodiments illustrate the detailed methods of the present invention, the present invention is not limited to these detailed methods, nor does it necessarily rely on these detailed methods for implementation. Those skilled in the art will appreciate that any improvements to the present invention, equivalent substitutions for raw materials in the products of the present invention, additions of auxiliary ingredients, and selection of specific methods, etc., fall within the scope of protection and disclosure of the present invention.

Claims

1. A solid electrolyte material, characterized in that The solid electrolyte material is amorphous, and the chemical formula of the solid electrolyte material is xLi3N·yLi2O·zLiF·TaCl5, 0.1≤x≤0.6, 0.1≤y≤2, 0.1≤z≤2.

2. The solid electrolyte material according to claim 1, characterized in that 0.3≤x≤0.5, 0.5≤y≤1, 1≤z≤2.

3. The solid electrolyte material according to claim 1 or 2, characterized in that The D50 particle size of the solid electrolyte material is 2-6 μm.

4. The solid electrolyte material according to claim 3, characterized in that The D90 particle size of the solid electrolyte material is 10-20 μm.

5. A method for preparing a solid electrolyte material, characterized in that: The preparation method is used to prepare the solid electrolyte material according to any one of claims 1 to 4, and the preparation method is carried out under an inert gas atmosphere, comprising: The four raw materials Li3N, Li2O, LiF and TaCl5 were pulverized and refined respectively; The powdered and refined materials are subjected to ball milling and mixing according to a preset molar ratio to obtain a precursor; The precursor is transferred to a muffle furnace for heat treatment to obtain the solid electrolyte material, wherein the heat treatment temperature is 250-450°C.

6. The preparation method according to claim 5, characterized in that The heat treatment time is 2-8 hours.

7. The preparation method according to claim 5, characterized in that The preparation method further comprises: The solid electrolyte material is ground and passed through a sieve to obtain a refined solid electrolyte material.

8. The preparation method according to any one of claims 5 to 7, characterized in that The ball-to-material ratio in the ball milling mixing process is (20-30):1; And / or, the ball milling speed is 150-250 rpm, the turning speed is 1-8 rpm, and the ball milling time is 4-8 h.

9. The preparation method according to any one of claims 5 to 7, characterized in that: The pulverizing speed of the pulverizing and refining treatment is 20000-30000 r / min, and the pulverizing time is 2-4 minutes.

10. A battery, characterized in that: The invention comprises the solid electrolyte material according to any one of claims 1 to 4, or the solid electrolyte material prepared by the preparation method of the solid electrolyte material according to any one of claims 5 to 9.

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