A halide high-entropy solid electrolyte, its preparation method, and its application in all-solid-state batteries

Abstract

This invention discloses a halide high-entropy solid electrolyte, its preparation method, and its application in all-solid-state batteries. The electrolyte has the general formula Li. 3‑x MCl6, wherein M includes at least five elements selected from the In, Zr, Ta, Y, Hf, and La series. The electrolyte is defined by the general formula Li. 3‑x MCl6 is weighed to obtain a metal chloride, and the resulting mixture is ball-milled. After ball milling, a halide high-entropy solid electrolyte is obtained. This invention achieves "direct synthesis of crystalline phase by ball milling" through optimized electrolyte preparation process, i.e., a "one-step" mechanical ball milling method. The preparation method of this invention can effectively avoid the problems of elemental segregation and impurity phase formation caused by heat treatment, thereby obtaining higher ionic conductivity and a purer phase. While reducing energy consumption and simplifying the process, it also improves the overall performance of the electrolyte.

Description

Technical Field

[0001] This invention belongs to the field of solid-state battery technology, specifically relating to a halide high-entropy solid electrolyte, its preparation method, and its application in all-solid-state batteries. Background Technology

[0002] Halogen solid electrolytes (such as Li3InCl6 and Li2ZrCl6) are considered key materials for constructing high-energy-density all-solid-state batteries due to their high ionic conductivity and good interfacial compatibility with high-voltage oxide cathodes. However, when matched with high-voltage oxide cathodes, chloride ions in traditional halide electrolytes are prone to electrochemical oxidation, leading to electrolyte structure degradation and a surge in interfacial impedance, which severely restricts the cycle life and energy density of the battery.

[0003] The design concept of high-entropy materials offers a new approach to solving the above problems. This strategy introduces multiple main elements into a single crystal lattice to form a stable structure with high configurational entropy (typically ≥1.5R). Studies have shown that introducing the high-entropy concept into halide electrolyte systems can not only kinetically limit chloride ion migration and oxidation through induced local lattice distortion, effectively broadening the electrochemical window [Nat. Commun. 2024, 15, 1481], but also thermodynamically enhance the intrinsic oxidation degradation potential of the material, thereby strengthening its interfacial stability with high-voltage cathodes [Angew. Chem. Int. Ed. 2025, 64,e202419735].

[0004] However, the development of existing high-entropy halide electrolytes still faces many challenges. Some existing technologies typically employ a wide range of elemental selections, which is detrimental to obtaining stable and homogeneous phases and makes precise performance control difficult. Of particular concern is that some reported high-entropy systems tend to use large amounts of expensive metal elements (such as In, Y, Er, and Yb), significantly increasing material costs and hindering their industrial application. Furthermore, traditional high-entropy electrolyte preparation methods often rely on high-temperature heat treatment processes to achieve crystallization. This process is energy-intensive, complex, and may induce elemental segregation or impurity phase formation, which is detrimental to large-scale production and cost control.

[0005] Therefore, there is an urgent need in this field to develop a high-entropy halide electrolyte solution that features precise element combination, simple preparation process, outstanding cost-effectiveness, and can simultaneously achieve high ionic conductivity and excellent high voltage stability. Summary of the Invention

[0006] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of the invention, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0007] In view of the problems existing in the above and / or prior art, the present invention is proposed.

[0008] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a halide high-entropy solid electrolyte.

[0009] To solve the above-mentioned technical problems, the present invention provides the following technical solution: the electrolyte has the general formula Li 3-x MCl6, wherein M includes at least five elements selected from the In, Zr, Ta, Y, Hf, and La series; and x ranges from 0.9 to 1.3.

[0010] As a preferred embodiment of the halide high-entropy solid electrolyte of the present invention, it has the following characteristics. The configurational entropy of the electrolyte is ≥1.5R, where R is the ideal gas constant; 120–160 mg of electrolyte was pressed into dense discs with a diameter of 10 mm and a thickness of approximately 0.6–1.2 mm under a uniaxial pressure of 360–380 MPa. These discs were connected to an electrochemical workstation, and electrochemical impedance spectroscopy was performed at 30 °C. The ionic conductivity of the electrolyte was found to be >1.2 mS·cm. -1 .

[0011] Another objective of this invention is to overcome the shortcomings of the prior art and provide a method for preparing a halide high-entropy solid electrolyte.

[0012] To solve the above-mentioned technical problems, the present invention provides the following technical solution: According to the general formula of the electrolyte, Li 3-x MCl6 was weighed to obtain a metal chloride, and the resulting mixture was ball-milled. After ball milling, the high-entropy solid electrolyte of the halide was collected.

[0013] As a preferred embodiment of the preparation method of the halide high-entropy solid electrolyte of the present invention, the ball milling is an intermittent ball milling mode, with each ball milling session lasting 6 to 8 minutes and a pause of 2 to 4 minutes.

[0014] In a preferred embodiment of the preparation method of the halide high-entropy solid electrolyte of the present invention, the total ball milling time is 30-40 hours and the ball milling speed is 500-800 rpm.

[0015] In a preferred embodiment of the method for preparing the halide high-entropy solid electrolyte of the present invention, the obtained mixture is ball-milled, wherein the ball-to-material ratio is 1:40~50.

[0016] In a preferred embodiment of the method for preparing the halide high-entropy solid electrolyte of the present invention, the ball milling atmosphere is either vacuum or inert atmosphere.

[0017] Another objective of this invention is to overcome the shortcomings of the prior art and provide an application of halide high-entropy solid electrolyte in the preparation of solid lithium-ion battery cathode materials.

[0018] To solve the above-mentioned technical problems, the present invention provides the following technical solution: The preparation of the solid-state lithium-ion battery cathode material includes grinding and mixing the halide high-entropy solid electrolyte of claim 1 with the cathode active material and the conductive agent to obtain the solid-state lithium-ion battery cathode material.

[0019] In a preferred embodiment of the application described in this invention, the mass ratio of the halide high-entropy solid electrolyte to the positive electrode active material and the conductive agent is 4~6:12~14:1.

[0020] In a preferred embodiment of the application described in this invention, the positive electrode active material is a high-nickel ternary material, and the chemical formula of the high-nickel ternary material is LiNi. 0.6 Mn 0.2 Co 0.2 O2, the conductive agent is vapor-grown carbon fiber.

[0021] Beneficial effects of this invention: (1) The halide high-entropy solid electrolyte provided by the present invention introduces lattice distortion through the high-entropy effect of multi-metal cations, thereby reducing the lithium-ion migration energy barrier and achieving a high ionic conductivity, which is higher than 1.2 mS cm⁻¹. -1 ; (2) The high-entropy design of the present invention stabilizes the crystal structure through entropy increase, effectively suppresses the phase change and interfacial side reaction of the electrolyte during battery cycling, and improves the structural stability and interfacial compatibility of the material. (3) The mechanical ball milling preparation method provided by the present invention is simple and efficient, and does not require subsequent high-temperature heat treatment. It can directly synthesize well-crystallized high-entropy electrolyte materials with low energy consumption, which is conducive to reducing production costs and is suitable for large-scale preparation. (4) The electrolyte prepared by this invention is applied to all-solid-state batteries and exhibits good electrochemical performance, providing a reliable electrolyte material for the development of a new generation of all-solid-state lithium batteries with high energy density and long cycle life. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a halide high-entropy solid electrolyte prepared in Example 1 of the present invention.

[0024] Figure 2 This diagram shows the rate performance of the halide high-entropy solid electrolyte prepared in Example 1 in an all-solid-state battery.

[0025] Figure 3 The images show the XRD patterns of the products obtained in Example 1 and Comparative Example 1 of this invention.

[0026] Figure 4 This is the XRD pattern of the product obtained in Comparative Example 2 of the present invention.

[0027] Figure 5 The impedance spectra are those of the products obtained in Example 1 and Comparative Examples 1-2 of this invention.

[0028] Figure 6 The images show the XRD patterns of the products obtained in Comparative Examples 3-5 of this invention.

[0029] Figure 7 The XRD patterns are of the products obtained in Comparative Examples 6-7 of this invention.

[0030] Figure 8 The impedance spectra of the products obtained in Comparative Examples 6-7 of this invention are shown.

[0031] Figure 9 This is the XRD pattern of the product obtained in Comparative Example 8 of the present invention.

[0032] Figure 10 The impedance spectrum of the product obtained in Comparative Example 8 of this invention is shown.

[0033] Figure 11 This is the XRD pattern of the product obtained in Example 2 of the present invention.

[0034] Figure 12 The impedance spectrum of the product obtained in Example 2 of this invention is shown.

[0035] Figure 13 The diagram shows the rate performance of the halide high-entropy solid electrolyte prepared in Example 2 of this invention in an all-solid-state battery. Detailed Implementation

[0036] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0037] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0038] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0039] Example 1 This embodiment provides a method for preparing a halide high-entropy solid electrolyte, specifically as follows: (1) According to Li2Zr 0.75 Ta 0.1 Hf 0.05 In 0.05 Sc 0.05 Anhydrous lithium chloride (LiCl, purity 99.99%), zirconium tetrachloride (ZrCl4, purity 99.95%), tantalum pentachloride (TaCl5, purity 99.9%), indium trichloride (InCl3, purity 99.99%), scandium trichloride (ScCl3, purity 99.9%), and hafnium tetrachloride (HfCl4, purity 99.9%) were weighed in stoichiometric proportions to obtain a mixed powder. (2) The mixed powder was ball-milled under an argon protective atmosphere. The ball-to-powder ratio was 1:50, the ball milling speed was 700 rpm, and the intermittent ball milling mode was controlled by a program. The specific parameters were: 6 min of ball milling followed by 3 min of pause, and the total effective ball milling time was 36 h. The white powder product collected after the ball milling was completed was the halide high-entropy solid electrolyte material.

[0040] The halide high-entropy solid electrolyte prepared in Example 1 is as follows: Figure 1 As shown.

[0041] The halide high-entropy solid electrolyte prepared in Example 1 was combined with the high-nickel ternary cathode active material LiNi 0.6 Mn 0.2 Co 0.2O2 (NMC622) and vapor-grown carbon fiber (VGCF) conductive agent were ground and mixed uniformly for 20 min at a mass ratio of 6:13:1 to obtain a composite cathode material. An all-solid-state battery was assembled using this cathode material, and its rate performance was tested. Figure 2 As shown.

[0042] from Figure 2 It can be seen that the battery assembled with the high-entropy solid electrolyte prepared in Example 1 can output a stable capacity at different current densities, and the capacity can be effectively recovered when returning to a low current density. This indicates that a stable and kinetically rapid interface is formed between the high-entropy electrolyte and the high-voltage NMC622 cathode material, ensuring the efficient migration of lithium ions between the electrode and the electrolyte.

[0043] Therefore, the high-entropy electrolyte prepared by this invention has the outstanding advantages of high ionic conductivity and good interfacial compatibility, thereby enabling the all-solid-state battery to have excellent rate performance and reversibility.

[0044] Comparative Example 1 The difference between this comparative example and Example 1 is that only the Li2Zr in step (1) is changed. 0.75 Ta 0.1 Hf 0.05 In 0.05 Sc 0.05 Cl6 is changed to Li2ZrCl6, specifically: Anhydrous lithium chloride (LiCl, 99.99%) and zirconium tetrachloride (ZrCl4, 99.95%) powders were weighed according to the stoichiometric ratio of Li2ZrCl6 to obtain a mixed powder. The remaining preparation methods were the same as in Example 1.

[0045] Phase analysis of the products obtained in Example 1 and Comparative Example 1 was performed by X-ray diffraction (XRD, Cu Kα radiation, λ=1.5406 Å), and the results are as follows: Figure 3 As shown in the figure, all diffraction peaks can be indexed to the Li₂ZrCl₆ structure (PDF#00-044-0286), indicating the successful synthesis of a high-entropy electrolyte material with a crystalline phase. Compared with the Li₂ZrCl₆ spectrum of Comparative Example 1, the diffraction peaks of Example 1 are broadened and slightly shifted, indicating that the introduction of multiple metal elements successfully induced lattice distortion, which is a typical characteristic of the high-entropy effect.

[0046] Comparative Example 2 The difference between this comparative example and Example 1 is that the halide high-entropy solid electrolyte material obtained by ball milling is further subjected to heat treatment, specifically: After pressing the halide high-entropy solid electrolyte material into sheet-like samples with a diameter of 10 mm under a pressure of 380 MPa, it was heated to 260 °C under vacuum at a heating rate of 2 °C / min and held at that temperature for 5 h. After cooling to room temperature, the solid electrolyte material of this comparative example was obtained.

[0047] The product obtained in Comparative Example 2 was subjected to phase analysis by X-ray diffraction (XRD, Cu Kα radiation, λ = 1.5406 Å), and the results are as follows: Figure 4 As shown. Comparison Figure 3 and Figure 4 As can be seen, in the diffraction pattern of Comparative Example 2, the main phase has undergone significant changes, indexing as a Li3InCl6 structure (PDF#04-009-9027). Simultaneously, distinct impurity phase diffraction peaks appear at specific diffraction angle positions (2θ≈29.9°, 49.8°). Figure 4 (As indicated in the text), this impurity peak can be indexed as a LiCl structure (LiCl PDF#04-006-5375). This indicates that the subsequent heat treatment process induced local elemental segregation or the formation of secondary crystalline phases, disrupting the ideal structural homogeneity of the high-entropy system.

[0048] Furthermore, 150 mg of the products obtained in Example 1 and Comparative Examples 1-2 were pressed into dense discs with a diameter of 10 mm and a thickness of approximately 0.6-1.2 mm under uniaxial pressure of 380 MPa in a glove box. The electrolyte discs were transferred to a sealed test fixture, connected to an electrochemical workstation, and their ionic conductivity was tested by electrochemical impedance spectroscopy (EIS) at 30 °C, with a frequency range of 7 MHz to 0.1 Hz and a perturbation voltage of 10 mV. The impedance spectra obtained are shown below. Figure 5 As shown, after fitting with ZView software, the ionic conductivity of the high-entropy electrolyte prepared in Example 1 was found to be 1.46 mS / cm. -1 This is much higher than that of Comparative Example 1 (0.42 mS·cm). -1 ) and Comparative Example 2 (0.29 mS·cm -1 While the subsequent heat treatment in Comparative Example 2 improved the crystallinity of the material to some extent, it also led to the formation of harmful impurity phases and a significant decrease in ionic conductivity. However, the "one-step" mechanical ball milling method of this invention can directly synthesize crystalline high-entropy electrolytes, effectively avoiding elemental segregation and impurity phase formation caused by heat treatment, thereby obtaining higher ionic conductivity and a purer phase. It is evident that this invention achieves comprehensive performance improvement while reducing energy consumption and simplifying the process.

[0049] Comparative Example 3 The difference between this comparative example and Example 1 is that only the ball milling speed in step (2) is adjusted to 400 rpm, while the rest of the preparation methods are the same as in Example 1, and the electrolyte material of this comparative example is obtained.

[0050] Comparative Example 4 The difference between this comparative example and Example 1 is that only the ball-to-material ratio in step (2) is adjusted to 1:30, while the rest of the preparation methods are the same as in Example 1, thus obtaining the electrolyte material of this comparative example.

[0051] Comparative Example 5 The difference between this comparative example and Example 1 is that only the total ball milling time in step (2) is adjusted to 20h, while the rest of the preparation methods are the same as in Example 1, and the electrolyte material of this comparative example is obtained.

[0052] Phase analysis of the products obtained in Comparative Examples 3-5 was performed by X-ray diffraction (XRD, Cu Kα radiation, λ=1.5406 Å), and the results are as follows: Figure 6 As shown, Comparative Examples 3-5 exhibited obvious diffraction peaks at positions such as 2θ≈29.9°, 34.7°, and 49.8°, which, after indexing, could be attributed to the LiCl phase (PDF#97-005-3818). No structure similar to the Li2ZrCl6 structure shown in Example 1 (PDF#00-044-0286) was clearly observed. This indicates that at lower ball milling speeds, ball milling ratios, and ball milling times, the mechanochemical energy input was insufficient, failing to fully drive the high-entropy reactions of the various metal chlorides. This resulted in some raw materials not reacting completely, and the presence of a large amount of unreacted LiCl impurities in the product, affecting the structural uniformity of the electrolyte. Therefore, excessively low ball milling speeds, ball milling ratios, and ball milling times cannot form a uniform high-entropy crystalline structure.

[0053] Comparative Example 6 The difference between this comparative example and Example 1 is that only the ball-to-material ratio in step (2) is adjusted to 1:60, while the rest of the preparation methods are the same as in Example 1, thus obtaining the electrolyte material of this comparative example.

[0054] Comparative Example 7 The difference between this comparative example and Example 1 is that only the total ball milling time in step (2) is adjusted to 50 hours, while the rest of the preparation methods are the same as in Example 1.

[0055] The products obtained in Comparative Examples 6 and 7 were subjected to phase analysis by X-ray diffraction (XRD, Cu Kα radiation, λ = 1.5406 Å), and the results are as follows: Figure 7 As shown in the figure, all diffraction peaks can be indexed to the Li2ZrCl6 structure (PDF#00-044-0286), indicating that a high-entropy electrolyte material with a crystalline phase has been successfully synthesized.

[0056] Furthermore, 150 mg of the product from comparative examples 6-7 was taken, pressed under the same conditions, and the ionic conductivity was tested. Figure 8 As shown, the conductivity values ​​of Comparative Example 6 and Comparative Example 7 are 1.07 mS / cm. -1 0.86 mS cm -1 The value was significantly lower than that of Example 1 (1.46 mS cm). -1 The conductivity data indicate that excessively long ball milling times may cause lattice damage, localized amorphization, or excessive particle refinement, which is detrimental to the formation and maintenance of long-range ordered structures, leading to a decrease in ionic conductivity. Simultaneously, an excessively high ball-to-powder ratio can easily lead to excessively high local temperatures and excessive powder compaction, affecting the uniformity of the reaction and phase purity, thus hindering the attainment of high ionic conductivity.

[0057] Comparative Example 8 The difference between this comparative example and Example 1 is that only step (1) is adjusted to: According to Li2In 0.75 Y 0.1 Hf 0.05 Sc 0.05 Er 0.05 Anhydrous lithium chloride (LiCl, purity 99.99%), indium trichloride (InCl3, purity 99.99%), yttrium trichloride (YCl3, purity 99.99%), erbium trichloride (ErCl3, purity 99.9%), hafnium tetrachloride (HfCl4, purity 99.9%), and scandium trichloride (ScCl3, purity 99.9%) were weighed in stoichiometric proportions to obtain a mixed powder; the remaining preparation methods were the same as in Example 1, thus obtaining the electrolyte material of this comparative example.

[0058] Phase analysis of the product obtained in Comparative Example 8 was performed by X-ray diffraction (XRD, Cu Kα radiation, λ=1.5406 Å), and the results are as follows: Figure 9 The analysis revealed that the main phase of the product was a Li3InCl6 structure (PDF#04-009-9027), with no obvious impurity peaks. Simultaneously, the conductivity of the product was tested, and the results are as follows: Figure 10 The results showed that the ionic conductivity was only about 0.34 mS·cm. -1 The value was significantly lower than that of Example 1 (1.46 mS cm). -1 While this combination meets the requirements for the number of high-entropy elements and the mixing entropy, it lacks elements such as Ta and Zr, which play a crucial role in promoting lithium-ion conduction, resulting in a decrease in ion migration performance. This illustrates that the selection of metal elements is critical to achieving high-performance high-entropy electrolytes.

[0059] Example 2 The difference between this embodiment and embodiment 1 is that only step (1) is adjusted as follows: According to Li2Zr 0.75 Ta 0.1 Hf 0.05 In 0.05 Y 0.05 Anhydrous lithium chloride (LiCl, purity 99.99%), zirconium tetrachloride (ZrCl4, purity 99.95%), tantalum pentachloride (TaCl5, purity 99.9%), indium trichloride (InCl3, purity 99.99%), yttrium trichloride (YCl3, purity 99.99%), and hafnium tetrachloride (HfCl4, purity 99.9%) were weighed in stoichiometric proportions to obtain a mixed powder; the remaining preparation methods were the same as in Example 1, thus obtaining the halide high-entropy solid electrolyte of this example.

[0060] Phase analysis of the product obtained in Example 2 was performed by X-ray diffraction (XRD, Cu Kα radiation, λ=1.5406 Å), and the results are as follows: Figure 11 As shown. Figure 11 As can be seen, Example 2 also successfully obtained a high-entropy electrolyte material with crystal orientation.

[0061] The ionic conductivity of the product obtained in Example 2 was tested, such as... Figure 12 As shown, the ionic conductivity of the halide high-entropy solid electrolyte prepared in Example 2, after fitting, is 1.27 mS·cm. -1 It was significantly higher than that of Comparative Example 1, but lower than that of Example 1.

[0062] The halide high-entropy solid electrolyte prepared in Example 2 was combined with the high-nickel ternary cathode active material LiNi. 0.6 Mn 0.2 Co 0.2 O2 (NMC622) and vapor-grown carbon fiber (VGCF) conductive agent were ground and mixed uniformly for 20 min at a mass ratio of 6:13:1 to obtain a composite cathode material. An all-solid-state battery was assembled using this cathode material, and its rate performance was tested. Figure 13 As shown, the battery assembled with the high-entropy electrolyte prepared in Example 2 also exhibits excellent rate performance and capacity retention.

[0063] contrast Figure 2 and Figure 13 This demonstrates that even without relying on expensive rare earth elements (by replacing Sc with Y), the preparation method of this invention can still impart stable and efficient electrochemical performance to all-solid-state batteries.

[0064] In summary, this invention achieves "direct synthesis of crystalline phases via ball milling" by optimizing the electrolyte preparation process, completely eliminating heat treatment, i.e., a "one-step" mechanical ball milling method. This ball milling process not only achieves mechanical mixing but also provides sufficient energy to drive the chemical reaction and form a long-range ordered crystal structure. The preparation method of this invention can effectively avoid the problems of elemental segregation and impurity phase formation caused by heat treatment, thereby obtaining higher ionic conductivity and a purer phase. While reducing energy consumption and simplifying the process, it also improves the overall performance of the electrolyte.

[0065] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A halide high-entropy solid electrolyte, characterized in that: The electrolyte has the general formula Li 3-x MCl6, wherein M includes at least five elements selected from the In, Zr, Ta, Y, Hf, and La series; and x ranges from 0.9 to 1.

3.

2. The halide high-entropy solid electrolyte as described in claim 1, characterized in that: It has the following characteristics, The configurational entropy of the electrolyte is ≥1.5R, where R is the ideal gas constant; 120–160 mg of electrolyte was pressed into dense discs with a diameter of 10 mm and a thickness of approximately 0.6–1.2 mm under a uniaxial pressure of 360–380 MPa. These discs were connected to an electrochemical workstation, and electrochemical impedance spectroscopy was performed at 30 °C. The ionic conductivity of the electrolyte was found to be >1.2 mS·cm. -1 .

3. The method for preparing halide high-entropy solid electrolyte as described in claim 1, characterized in that: The electrolyte according to claim 1 has the general formula Li. 3-x MCl6 was weighed to obtain a metal chloride, and the resulting mixture was ball-milled. After ball milling, the high-entropy halide solid electrolyte was collected.

4. The method for preparing halide high-entropy solid electrolyte as described in claim 2, characterized in that: The ball milling is an intermittent ball milling mode, with each ball milling session lasting 6 to 8 minutes and followed by a 2 to 4 minute pause.

5. The method for preparing halide high-entropy solid electrolyte as described in claim 2, characterized in that: The total ball milling time is 30-40 hours, and the ball milling speed is 500-800 rpm.

6. The method for preparing halide high-entropy solid electrolyte as described in claim 2, characterized in that: The obtained mixture is ball-milled, wherein the ball-to-material ratio is 1:40~50.

7. The method for preparing halide high-entropy solid electrolyte as described in claim 2, characterized in that: The atmosphere used in the ball mill is either a vacuum or an inert atmosphere.

8. The application of the halide high-entropy solid electrolyte as described in claim 1 in the preparation of solid-state lithium-ion battery cathode materials, characterized in that: The preparation of the solid-state lithium-ion battery cathode material includes grinding and mixing the halide high-entropy solid electrolyte of claim 1 with the cathode active material and the conductive agent to obtain the solid-state lithium-ion battery cathode material.

9. The application as described in claim 8, characterized in that: The mass ratio of the halide high-entropy solid electrolyte to the positive electrode active material and conductive agent is 4~6:12~14:

1.

10. The application as described in claim 9, characterized in that: The positive electrode active material is a high-nickel ternary material, and the chemical formula of the high-nickel ternary material is LiNi. 0.6 Mn 0.2 Co 0.2 O2, the conductive agent is vapor-grown carbon fiber.

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