Oxyhalide electrolyte, preparation method of oxyhalide electrolyte and solid-state battery

Abstract

The embodiment of the invention provides an oxyhalide electrolyte, a preparation method of the oxyhalide electrolyte and a solid-state battery. The method comprises the following steps: weighing raw materials according to components shown in a chemical general formula of an inner core of the oxyhalide electrolyte and a molar ratio; mixing the raw materials to generate a precursor mixture; performing first heat treatment on the precursor mixture in an inert atmosphere to obtain a crystalline-state core precursor; and finally, carrying out surface fluorination treatment on the crystalline-state core precursor to obtain the oxyhalide electrolyte. The method is used for achieving the collaborative optimization effect of considering the voltage window, the ionic conductivity and the ionic stability.

Description

Technical Field

[0001] This application relates to the technical field of solid-state batteries, and particularly to an oxychloride electrolyte, a preparation method of the oxychloride electrolyte, and a solid-state battery. Background Art

[0002] Oxychloride solid electrolytes have multiple advantages such as high ionic conductivity, excellent ductility, and good compatibility with cathode materials, and have become a new type of solid electrolyte material that has received much attention in recent years. However, there are still problems with the oxychloride electrolyte such as insufficient upper limit of the voltage window and poor air stability.

[0003] Currently, the above problems are mainly solved by fluorine doping. Specifically, a fluorine source (such as LiF, , HF, etc.) is directly introduced during the preparation process of the oxychloride electrolyte, and through processes such as high-temperature sintering, mechanochemical ball milling, or sol-gel, fluoride ions in-situ replace chlorine / bromine ions in the electrolyte lattice to form a fluorine-doped solid solution.

[0004] However, the oxychloride electrolytes in the prior art cannot achieve the coordinated optimization of the voltage window, ionic conductivity, and ionic stability. Summary of the Invention

[0005] Embodiments of this application provide an oxychloride electrolyte, a preparation method of the oxychloride electrolyte, and a solid-state battery, so as to achieve the technical effect of coordinating and optimizing the voltage window, ionic conductivity, and ionic stability.

[0006] In a first aspect, embodiments of this application provide an oxychloride electrolyte, including: [[ID=二十六]]

[0007] A core and a coating layer covering the surface of the core;

[0008] The core is crystalline and has a chemical general formula of xLi2O-TaM5, and the chemical general formula of the coating layer is Li<……>TaO b M c-d F d ;

[0009] Where M is at least one of Cl, Br, and I, the value range of x is 0.1≤x≤3, the value range of a is 0.2≤a≤6, the value range of b is 0.1<b≤3, the value range of c is 1≤c<5, and the value range of d is 0<d≤4. [[ID=四十三]]

[0010] In a possible implementation manner, the value range of x is 0.2≤x≤0.8, the value range of a is 1≤a≤4, the value range of b is 0.‘5<b≤2, the value range of c is 2≤c≤4.4, and the value range of d is 0.6≤d≤3. Note: There seems to be some incomplete or incorrect tags in the original text, such as "<……>" which is not properly formatted. I've translated it as best as possible while keeping the original tags intact. If you can correct the original text, it will be possible to provide a more accurate translation.

[0011] In one possible implementation, the thickness of the coating layer is 1-100 nm.

[0012] In one possible implementation, the median particle size of the halide electrolyte is 0.05-100 μm.

[0013] Secondly, embodiments of this application provide a method for preparing a halide oxide electrolyte, the method being used to prepare a halide oxide electrolyte as shown in the first aspect and / or various possible embodiments of the first aspect, the method comprising:

[0014] Weigh the raw materials according to the composition and molar ratio shown in the general chemical formula of the core of the halide oxide electrolyte;

[0015] The raw materials are mixed to generate a precursor mixture;

[0016] The precursor mixture is subjected to a first heat treatment in an inert atmosphere to obtain a crystalline core precursor.

[0017] The crystalline core precursor is subjected to surface fluorination treatment to obtain the halide electrolyte.

[0018] In one possible implementation, the surface fluorination treatment of the crystalline core precursor to obtain the halide electrolyte includes:

[0019] The crystalline core precursor is subjected to a second heat treatment in a fluorine-containing atmosphere to obtain the halide electrolyte.

[0020] In one possible implementation, the fluorine-containing atmosphere comprises fluorine gas and / or HF gas.

[0021] In one possible implementation, the temperature of the first heat treatment is 80-400°C, and / or the duration is 1-30 hours.

[0022] In one possible implementation, the temperature of the second heat treatment is 100-220°C, and / or the duration is 1-100 min.

[0023] Thirdly, embodiments of this application provide a solid-state battery, including: a positive electrode, a negative electrode, and a halide oxide electrolyte;

[0024] The halide electrolyte is the halide electrolyte as shown in the first aspect and / or various possible embodiments of the first aspect above, or a halide electrolyte prepared by the preparation method of the halide electrolyte as shown in the second aspect and / or various possible embodiments of the second aspect above.

[0025] The halide oxide electrolyte, its preparation method, and solid-state battery provided in this application, under relatively mild synthesis conditions, utilize solid-state sintering to obtain a crystalline core precursor. The crystalline core precursor is then annealed in a fluorine-containing atmosphere, and its surface is fluorinated via a gas-solid reaction to form a core-shell structured halide oxide electrolyte. The surface coating layer is composed of a fluorine-containing component, Li. a TaO b M c-d F d Its core is xLi₂O-TaM₅, which is free of fluorine components. This method is simple, efficient, and low-cost, making it suitable for industrial production. The halide oxide electrolyte prepared by this method has a low bulk fluorine content, allowing it to maintain high ionic conductivity and good mechanical strength while improving its voltage window and air stability. Furthermore, this halide oxide electrolyte holds promise for use with high-voltage cathode materials, achieving excellent cycle performance and rate capability, thus realizing the commercial application value of all-solid-state rechargeable batteries. Attached Figure Description

[0026] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0027] Figure 1 A schematic flowchart illustrating the preparation method of the halide oxide electrolyte provided in this application;

[0028] Figure 2 X-ray diffraction patterns (XRD) of Examples 1, 2, and 3 provided in this application;

[0029] Figure 3 Application performance diagram of Embodiment 2 provided in this application.

[0030] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0031] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0032] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties. Furthermore, the collection, use and processing of the relevant data must comply with relevant laws, regulations and standards, and corresponding operation entry points are provided for users to choose to authorize or refuse.

[0033] First, the application background of this application will be explained:

[0034] Since the advent of lithium-ion batteries in 1991, they have been widely used in portable electronic products (such as laptops, mobile phones, and digital cameras) and electric vehicles. However, recent frequent safety accidents involving new energy vehicles are primarily due to the fact that traditional lithium-ion batteries use flammable organic solvents as electrolytes, posing significant safety risks, and conventional improvement solutions are unable to fundamentally solve this problem.

[0035] In contrast, solid-state lithium-ion batteries using solid electrolytes offer significant safety advantages. They not only eliminate the safety hazards posed by the flammability of electrolytes but also greatly simplify battery manufacturing and packaging processes, while simultaneously improving energy density, reliability, and structural design freedom. Among various novel battery systems, solid-state batteries are widely recognized as the next-generation technology closest to industrialization, a view that has become a consensus within both industry and the scientific community.

[0036] To meet the demands of high energy density, solid-state battery cathode materials typically employ high-potential ternary systems, which imposes stringent requirements on the electrolyte for high-potential ionic stability (>4V). Among inorganic electrolyte materials, oxide electrolytes possess high oxidation potentials and exhibit good compatibility with high-voltage ternary cathode materials; however, these materials suffer from limitations in improving ionic conductivity, high rigidity, and poor ductility, resulting in relatively high interfacial contact impedance with the cathode material.

[0037] In contrast, sulfide electrolyte systems typically exhibit high ionic conductivity and excellent ductility, enabling them to form dense physical contact with cathode materials. However, sulfide electrolytes suffer from relatively high raw material costs and low oxidation potential (usually <3V). When in direct contact with cathode materials, they are prone to severe side reactions during cycling, affecting battery performance and ionic stability.

[0038] Compared to sulfide electrolytes and oxide electrolytes, halooxide solid electrolytes possess multiple advantages, including high ionic conductivity, excellent ductility, and good compatibility with cathode materials, making them a promising new type of solid electrolyte material in recent years. However, to further explore the capacity potential of cathode materials, halooxide electrolytes struggle to meet the application requirements of higher oxidation potentials (>4.3V); simultaneously, these materials also suffer from inherent drawbacks such as high moisture sensitivity and poor air stability.

[0039] To address the issues of insufficient upper voltage window and poor air stability in halide oxide solid electrolytes, existing techniques typically employ fluorine doping. Specifically, this involves directly introducing a fluorine source (such as LiF, etc.) during the preparation of the halide oxide electrolyte. Fluorine ions (such as HF) are used to replace chloride / bromine ions in the electrolyte lattice in situ through high-temperature sintering, mechanical-chemical ball milling, or sol-gel processes to form fluorine-doped solid solutions.

[0040] However, due to the extremely low ionic conductivity of fluorides, lattice substitution by fluoride ions disrupts the original ion transport channels, causing ionic conductivity to decrease linearly with increasing fluorine doping concentration. In other words, at low fluorine doping concentrations, the effects on widening the voltage window and improving air stability are limited; while high fluorine doping concentrations can improve ionic stability, ionic conductivity will decrease significantly.

[0041] In summary, existing technologies cannot simultaneously optimize the voltage window, ionic conductivity, and ionic stability of halide electrolytes.

[0042] Based on the aforementioned technical problems, the technical concept of this application is as follows: During their research on halide oxide electrolytes, the inventors discovered that the crystalline xLi₂O-TaM₅ system itself possesses a good lithium-ion conductivity. If only fluorination treatment is used to form Li₂O on its surface... a TaO b M c-d F d The coating layer not only ensures improved ion stability and voltage window but also prevents fluoride ions from damaging the core ion transport channels. This core-shell structured halide electrolyte has a low fluoride content, which can improve ion stability and voltage window through the coating layer, while effectively retaining ionic conductivity by relying on the high conductivity of the crystalline core, thus achieving a synergistic optimization of voltage window, ionic conductivity, and ion stability.

[0043] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0044] Figure 1 Schematic flow chart of the preparation method of the oxynitride electrolyte provided for this application, as Figure 1 shown, this method includes:

[0045] S11. Weigh raw materials according to the components and molar ratios shown by the chemical general formula of the core of the oxynitride electrolyte.

[0046] Among them, the oxynitride electrolyte includes a core and a coating layer coated on the surface of the core. The core is crystalline and its chemical general formula is xLi2O-TaM5, and the chemical general formula of the coating layer is Li a TaO b M c-d F d .

[0047] Among them, M is at least one of Cl, Br, and I.

[0048] Among them, the value range of x is 0.1 ≤ x ≤ 3, the value range of a is 0.2 ≤ a ≤ 6, the value range of b is 0.1 < b ≤ 3, the value range of c is 1 ≤ c < 5, and the value range of d is 0 < d ≤ 4.

[0049] Among them, due to the existence of F element in the coating layer of the oxynitride electrolyte, the voltage window and air stability of the oxynitride solid electrolyte are improved; while there is no F element in the core of the oxynitride electrolyte, which makes the main body of the oxynitride electrolyte have a low fluorine content. By using the core with higher lithium ion conduction efficiency, the main body of the oxynitride electrolyte has excellent electrochemical oxidation potential and air stability while maintaining high ionic conductivity.

[0050] Furthermore, the value range of x is 0.2 ≤ x ≤ 0.8, the value range of a is 1 ≤ a ≤ 4, the value range of b is 0.5 < b ≤ 2, the value range of c is 2 ≤ c ≤ 4.4, and the value range of d is 0.6 ≤ d ≤ 3.

[0051] It should be understood that when the value range of x is 0.2 ≤ x ≤ 0.8, the core can form a crystalline phase with both structural ion stability and high ion conduction efficiency, avoiding phase separation caused by excess, and ensuring the density of the transmission channels, providing an excellent ionic conductivity basis for the electrolyte; considering that too low content will limit the ion migration rate, and too high content is prone to cause structural agglomeration. When the value range of a is 1 ≤ a ≤ 4, it can not only meet the charge balance of Ta (+5 valence), O (-2 valence), M (-1 valence), F (-1 valence), but also meet The transmission requirements are met to achieve a balance between conductivity and the stability of structural ions; when the value range of b is 0.5 < b ≤ 2, the coating layer can form a sufficiently dense structure to improve the voltage window and air stability, and will not cause the clogging of ion transport channels due to excessive O, effectively taking into account both chemical ion stability and ionic conductivity; when the value range of c is 2 ≤ c ≤ 4.4, the total stoichiometric ratio of M(Cl / Br / I) is highly compatible with the coordination environment of Ta (such as six-coordination), which can not only ensure the integrity of the framework structure, but also avoid the increase in transport resistance caused by overcrowding of M ions, providing spatial conditions for the rapid migration of ions; considering that too low F doping will lead to insignificant performance improvement, and too high F doping will lead to a sharp drop in ionic conductivity, when the value range of d is 0.6 ≤ d ≤ 3, an optimal compromise between performance improvement and conductivity loss is achieved.

[0052] Exemplarily, xLi2O-TaM5 can be 0.8Li2O-TaCl5, 0.6Li2O-TaCl5, 0.2Li2O-TaCl5, 0.6Li2O-TaBr5, 0.6Li2O-TaCl4Br, 0.6Li2O-TaCl 4.9 Br 0.1 I 0.1 etc.

[0053] It should be understood that in addition to the above examples, according to the elements contained in M and different selections of x within its value range, the oxyhalide electrolyte can also have other specific chemical formulas to meet the specific requirements of users in specific application scenarios, which are not limited here.

[0054] It should be understood that the raw materials weighed in this step contain Li element, M element, O element and Ta element.

[0055] Exemplarily, when the chemical formula of the oxyhalide electrolyte is 0.8Li2O-TaCl5, the weighed raw materials are Li2O and TaCl5, and the molar ratio of Li2O:TaCl5 is 0.8:1; when the chemical formula of the oxyhalide electrolyte is 0.6Li2O-TaCl5, the weighed raw materials are Li2O and TaCl5, and the molar ratio of Li2O:TaCl5 is 0.6:1; when the chemical formula of the oxyhalide electrolyte is 0.2Li2O-TaCl5, the weighed raw materials are Li2O and TaCl5, and the molar ratio of Li2O:TaCl5 is 0.2:1.

[0056] It can be understood that in addition to the above specific molar ratios, according to the different chemical formulas of the oxyhalide electrolyte, other raw material components and the molar ratios between other raw material components can also be obtained to meet the specific requirements of users in specific application scenarios.

[0057] In practical applications, considering that Li₂O is a white solid that readily absorbs moisture and CO₂ from the air, the raw materials can be weighed under an inert atmosphere to prevent contamination or deterioration during the preparation process.

[0058] The inert atmosphere includes inert gases, which are gases that are chemically very inert. The gases in the inert atmosphere are at least one of argon, nitrogen, and helium.

[0059] Alternatively, the raw materials can be weighed using a balance or other weighing tools.

[0060] S12. Mix the raw materials to generate a precursor mixture.

[0061] In one possible implementation, the weighed raw materials can be added to an agate mortar and mixed using a dry grinding method to obtain a precursor mixture.

[0062] In another possible implementation, the weighed raw materials can be added to a planetary ball mill to mix them and obtain a precursor mixture.

[0063] In another possible implementation, the weighed raw materials can be added to an air jet mill to mix them and obtain a precursor mixture.

[0064] It should be understood that the raw materials can also be mixed by other mixing methods to improve the uniformity of the resulting precursor mixture. The embodiments of this application do not limit the specific mixing method.

[0065] Alternatively, to prevent the raw materials from being contaminated or deteriorated during the mixing process, the raw materials can be mixed in an inert gas environment.

[0066] S13. The precursor mixture is subjected to a first heat treatment in an inert atmosphere to obtain a crystalline core precursor.

[0067] Heat treatment refers to the process of changing the structure or chemical composition of a precursor mixture through heating, holding and cooling. The purpose is to promote internal reactions in the precursor, eliminate impurities / defects, and form a stable crystalline core precursor.

[0068] In one possible implementation, the first heat treatment can be specifically implemented as follows: the precursor mixture is loaded into a high-temperature resistant container (such as an alumina crucible) and placed in a heat treatment furnace. Then, an inert gas is introduced, and the interior of the heat treatment furnace is heated, and after the heating is completed, the temperature is maintained for a specific time to complete the reaction. Finally, after the reaction is complete, the high-temperature resistant container is cooled.

[0069] In this process, the first heat treatment is carried out in an inert atmosphere to prevent the crystalline core precursor from reacting with other components in the air.

[0070] The temperature of the first heat treatment is 80-400℃, and / or the duration is 5-15h.

[0071] Understandably, the lower temperature limit of 80°C provides the basic energy required for the raw material reaction, preventing incomplete reaction that would hinder the formation of a regular crystalline structure, while also reducing energy consumption and equipment requirements. The upper temperature limit of 400°C effectively prevents the volatilization of components such as Li and M (Cl / Br / I) and the thermal decomposition of the core structure, and also avoids excessive particle sintering and agglomeration, ensuring the uniformity of subsequent fluorination coating. The lower time limit of 5 hours ensures sufficient diffusion reaction of the precursor and complete grain growth, forming a stable crystalline framework; the upper time limit of 15 hours avoids excessive particle growth or agglomeration that blocks ion transport channels, while controlling production efficiency and cost. It should be understood that this temperature and time range can also accommodate the differences in reactivity of different halogen raw materials, adapting to the needs of laboratory pilot tests and small-scale production, ensuring the high ion conductivity of the crystalline core while balancing product consistency and process flexibility.

[0072] In practical applications, the temperature of the first heat treatment is 150-350℃, and / or the duration is 1-30 hours. It should be understood that the above temperature and duration ranges are parameter ranges for practical applications, representing process optimization intervals based on these basic ranges to adapt to the needs of large-scale production.

[0073] Optionally, the first heat treatment includes a staged heating process. For example, the temperature can be raised from room temperature to 200°C and held for 2 hours to remove moisture / impurities. Then, the temperature is raised to the target temperature and held. Similarly, the cooling process is staged and similar to the heating process, so it will not be described in detail here.

[0074] S14. Surface fluorination treatment is performed on the crystalline core precursor to obtain halide oxide electrolyte.

[0075] Among them, surface fluorination treatment refers to the process of modifying the surface of crystalline core precursors with fluorine only. The core is to allow fluorine to react or combine with the components on the core surface to form a uniform fluorinated coating layer, namely Li. a TaO b M c-d F d Without altering the core's crystalline structure and high ion conductivity.

[0076] In one possible implementation, the crystalline core precursor is subjected to a second heat treatment in a fluorine-containing atmosphere to obtain a halide electrolyte.

[0077] The second heat treatment can be specifically implemented as annealing.

[0078] The fluorine-containing atmosphere includes fluorine gas and / or HF gas.

[0079] The second heat treatment is performed at a temperature of 100-220℃ and / or for a duration of 1-100 min.

[0080] Understandably, the lower limit of 100℃ can activate the reaction between fluorine and the core surface components, ensuring the formation of a uniform and dense Li. a TaO b M c-d F d The coating layer, with an upper limit of 220℃, is significantly lower than the stable temperature of the core crystalline structure, preventing excessive fluoride ion penetration that could damage the core ion transport channels. It also prevents an excessively thick coating layer from affecting ion conduction. A minimum processing time of 1 minute accommodates rapid modification needs while maintaining production efficiency; a maximum of 100 minutes meets the requirements for thick coating layer preparation, ensuring improved voltage window and ion stability. It should be understood that the above temperature and processing time ranges are also compatible with the varying reactivity of different halogen raw materials, adapting to both laboratory-scale and large-scale production scenarios. This ensures a synergistic effect of improved voltage window and air stability through the coating layer, and guaranteed ion conductivity through the core, while also maintaining process flexibility and cost control.

[0081] In practical applications, the temperature of the second heat treatment is 100-220℃, and / or the duration is 5-20 minutes. It should be understood that the above temperature and duration ranges are parameter ranges for practical applications, representing process optimization intervals based on these basic ranges to adapt to the needs of large-scale production.

[0082] In practical applications, the thickness of the coating layer is 1-100nm.

[0083] Understandably, a minimum coating thickness of 1 nm is sufficient to ensure the formation of a continuous and dense Li. a TaO b M c-d F d The coating layer fully utilizes the role of fluorine in improving the voltage window and air stability, avoiding the problem that insufficient improvement effect on voltage window and air stability due to excessive thickness; the upper limit of 100nm can prevent the coating layer from being too thick and hindering lithium-ion transport, ensuring that the high ionic conductivity of the core is not significantly affected, while avoiding an increase in the overall fluorine content of the material.

[0084] Among them, the median particle size of halide oxide electrolytes is 0.05-100 μm.

[0085] It should be understood that the median particle size (also known as D50) refers to the particle size corresponding to 50% of the cumulative particle size distribution, that is, half of the particles have a particle size greater than this value and half have a particle size less than this value, which can intuitively reflect the overall coarseness of the halide oxide electrolyte particle group.

[0086] When the median particle size of halide oxide electrolytes is 0.05-100μm, the lower limit of 0.05μm can ensure sufficient particle specific surface area, which is conducive to close contact with electrode materials, reducing interfacial impedance, and shortening the lithium ion transport path to ensure high ion conduction efficiency. The upper limit of 100μm can avoid the problem of uneven stacking and difficult molding caused by excessively large particles, or poor dispersibility when mixed with electrodes, thus ensuring the integrity of the electrolyte layer structure.

[0087] The method for preparing halooxide electrolytes provided in this application involves weighing raw materials according to the composition and molar ratio shown in the general chemical formula of the core of the halooxide electrolyte. The raw materials are then mixed to generate a precursor mixture. Next, the precursor mixture undergoes a first heat treatment in an inert atmosphere to obtain a crystalline core precursor. Finally, the crystalline core precursor is subjected to surface fluorination treatment to obtain the halooxide electrolyte. In this technical solution, under relatively mild synthesis conditions, a crystalline core precursor is obtained by solid-state sintering. The crystalline core precursor is then annealed in a fluorine-containing atmosphere, and surface fluorination of the crystalline core precursor is achieved through a gas-solid reaction to form a core-shell structured halooxide electrolyte, with a surface coating of fluorine-containing component Li. a TaO b M c-d F d Its core is xLi₂O-TaM₅, which is free of fluorine components. This method is simple, efficient, and low-cost, making it suitable for industrial production. The halide oxide electrolyte prepared by this method has a low bulk fluorine content, allowing it to maintain high ionic conductivity and good mechanical strength while improving its voltage window and air stability. Furthermore, this halide oxide electrolyte holds promise for use with high-voltage cathode materials, achieving excellent cycle performance and rate capability, thus realizing the commercial application value of all-solid-state rechargeable batteries.

[0088] The technical effects of this application will be illustrated below through several embodiments and comparative examples.

[0089] Example 1

[0090] Halogen oxide electrolytes are prepared by the following steps:

[0091] Step 1: Weigh 20g of raw materials (Li2O and TaCl5) at a molar ratio of 0.8:1 and add them to a ball mill jar. Seal the jar and mix the materials using a planetary ball mill at 200rpm for 40min to obtain a precursor mixture.

[0092] Step 2: Sinter the precursor mixture at 250°C in an argon atmosphere for 6 hours to obtain a crystalline core precursor with a composition of 0.8Li2O-TaCl5.

[0093] Step 3: Under normal pressure, the crystalline core precursor is annealed in a dry HF atmosphere at a temperature of 120°C for 10 min to obtain a halide oxide electrolyte, wherein the F element is distributed in the region with a depth ≤60 nm on the surface of the powder particles.

[0094] Example 2

[0095] The difference from Example 1 is that the molar ratio of Li2O to TaCl5 is 0.6:1, and the chemical formula of the resulting crystalline core precursor is 0.6Li2O-TaCl5.

[0096] Example 3

[0097] The difference from Example 1 is that the molar ratio of Li2O to TaCl5 is 0.2:1, and the chemical formula of the resulting crystalline core precursor is 0.2Li2O-TaCl5.

[0098] Example 4

[0099] The difference from Example 1 is that the annealing time of the crystalline core precursor in a dry HF atmosphere is 5 minutes.

[0100] Example 5

[0101] The difference from Example 1 is that the annealing time of the crystalline core precursor in a dry HF atmosphere in step 3 is 20 min.

[0102] Example 6

[0103] The difference from Example 1 is that the annealing time of the crystalline core precursor in a dry F2 atmosphere is 10 min.

[0104] Example 7

[0105] The difference from Example 1 is that the raw materials are Li2O and TaBr5, and the molar ratio of Li2O to TaBr5 is 0.6:1, and the chemical formula of the resulting crystalline core precursor is 0.6Li2O-TaBr5.

[0106] Example 8

[0107] The difference from Example 1 is that the raw materials are Li2O and TaCl4Br, and the molar ratio of Li2O to TaCl4Br is 0.6:1, and the chemical formula of the resulting crystalline core precursor is 0.6Li2O-TaCl4Br.

[0108] Example 9

[0109] The difference from Example 1 is that the raw materials are Li2O and TaCl. 4.9 Br 0.1 I 0.1 And Li2O and TaCl 4.9 Br 0.1 I 0.1 The molar ratio is 0.6:1, and the chemical formula of the resulting crystalline core precursor is 0.6Li₂O-TaCl. 4.9 Br 0.1 I 0.1 .

[0110] Example 10

[0111] The difference from Example 1 is that the heat treatment temperature in step 2 is 150°C.

[0112] Example 11

[0113] The difference from Example 1 is that the heat treatment temperature in step 2 is 300°C.

[0114] Comparative Example 1

[0115] Li2O and TaCl5 were weighed at a molar ratio of 0.6:1, with a total mass of 20g. The raw materials were added to a ball mill jar and sealed. The mixture was then ball-milled at 600rpm for 12h using a planetary ball mill to obtain the halide electrolyte of Comparative Example 1.

[0116] Comparative Example 2

[0117] Li₂O and TaCl₅ were weighed at a molar ratio of 0.6:1, totaling 20 g of raw materials, and added to a ball mill jar. The mixture was sealed and then mixed using a planetary ball mill at 200 rpm for 40 min to obtain a precursor mixture. Subsequently, the precursor mixture was sintered at 250 °C under an argon atmosphere for 6 h to obtain the halide electrolyte of Comparative Example 2 with a composition of 0.6Li₂O-TaCl₅.

[0118] Test case

[0119] Test Example 1

[0120] Ionic conductivity test: 100 mg of halide oxide electrolyte powder was weighed and placed inside a pressure molding mold. A pressure of 300 MPa was applied to the halide oxide electrolyte powder for molding. Under pressure, the impedance value of the halide oxide electrolyte material was measured at room temperature (30 °C) using an electrochemical workstation (Solarton 1260) and electrochemical impedance spectroscopy. The real value of the impedance at the measurement point with the smallest absolute value of multiple impedance phases was taken as the resistance value (RSE) of the electrolyte material relative to ion transport. Using this resistance value, based on the formula... The ionic conductivity is calculated. Here, σ is the ionic conductivity, RSE is the measured resistance of the electrolyte material, S is the surface area of ​​the electrolyte material under applied pressure, and t is the thickness of the electrolyte material under applied pressure.

[0121] Test Example 2

[0122] Ion conductivity test after dry room exposure: After performing the ion conductivity test as described above, the room temperature ion conductivity of the sample is recorded as σ0. Take a 2g sample and place it in a -45℃ dew point environment for 3 hours. Measure the room temperature ion conductivity after this period, using the same method as above. The ion conductivity after the test is σ0. t .

[0123] Test Example 3

[0124] Electrochemical oxidation potential test: The electrochemical oxidation stability potential was measured using linear voltammetry. The cell configuration was BE / SSE+C / SSE / Li, the scan rate was 1 mV / s, and the voltage range was Voc~7V.

[0125] Test Example 4

[0126] Solid-state battery cycle performance testing: Under an argon atmosphere, halooxide electrolytes and NCM811 cathodes prepared in the examples and comparative examples were weighed in a 30:70 ratio and uniformly mixed to prepare a composite cathode material. 100 mg of Li6PS5Cl sulfide solid electrolyte was added to a 10 mm diameter insulating test sleeve, and a pressure of 300 MPa was applied and held for 2 minutes to form the solid electrolyte layer. 20 mg of the resulting composite cathode material was poured into one side of the pressed electrolyte layer, and a pressure of 360 MPa was applied and held for 5 minutes to form the solid electrolyte layer. A lithium-indium alloy sheet was inserted into the other side of the electrolyte layer, and a pressure of 80 MPa was applied to form the solid electrolyte layer. The cathode composite layer, solid electrolyte layer, lithium-indium alloy sheet, and stainless steel current collectors on both sides constituted a test all-solid-state battery. The assembled all-solid-state battery pack was placed in a 30°C constant temperature chamber for cycle performance testing. The test conditions were: first-cycle charge-discharge performance and cycle charge-discharge performance testing of the solid-state battery using a current density of 1C. The voltage range for the test was set to 2.6-4.3V (Li+ / Li).

[0127] For example, the test results of each embodiment and each comparative example are shown in Tables 1 and 2.

[0128] Table 1. Test results of each embodiment and each comparative example, Test Examples 1, 2, and 3.

[0129]

[0130] As shown in Table 1, the ionic conductivity of the halide electrolyte prepared through the embodiments of this application before exposure is ( ) and post-exposure ionic conductivity ( Both were significantly higher than those of control example 1 (before and after exposure, 2.2), which did not undergo surface fluorination treatment. ) and Comparative Example 2 (before and after exposure 2.9, Furthermore, the conductivity decays minimally after exposure, demonstrating excellent air stability. Simultaneously, the voltage window of the halide electrolytes prepared through the embodiments of this application reaches 4.30-4.45V, significantly wider than the comparative examples (3.75-3.78V), allowing for better adaptation to high-voltage cathode materials. Moreover, regardless of adjustments to the core-shell molar ratio (0.2-0.8), fluorination annealing time (5-20 min), halogen element combination (Cl / Br / I), or first heat treatment temperature (150-300℃), the embodiments maintain the synergistic advantages of high conductivity, strong ionic stability, and a wide voltage window, fully verifying the process flexibility and product performance reliability of this technical solution, far exceeding the comparative schemes without core-shell structure and surface fluorination treatment.

[0131] Table 2 Test results of each embodiment and each comparative example, Test Example 4.

[0132]

[0133] As shown in Table 2, the first-cycle discharge specific capacity of the core-shell structured halide electrolytes prepared in the embodiments of this application generally reaches [value missing]. Overall, it is higher than that of Comparative Example 1 ( ) and Comparative Example 2 ( This demonstrates a stronger charge storage capacity. Furthermore, the capacity retention rates of the embodiments after 550 cycles were all 65.9%-83.5%, far exceeding the 51%-52% of the comparative examples, exhibiting excellent cycle ion stability. Even with adjustments to the core... Despite variations in the molar ratio of tantalum halide, fluorination annealing time, halogen element combination (Cl / Br / I single or mixed), and first heat treatment temperature, the embodiments still consistently maintain high first-cycle capacity and excellent cycle retention. This fully demonstrates that the core-shell structure design and surface fluorination treatment of this technical solution effectively improve the interfacial compatibility and structural ionic stability of the electrolyte and electrode, resulting in performance far exceeding that of the comparative schemes that do not employ this design. It is also more suitable for the long-term use requirements of all-solid-state secondary batteries.

[0134] Figure 2 The XRD patterns of Examples 1, 2, and 3 provided in this application are shown. It should be understood that an XRD pattern is a characteristic spectrum formed when X-rays are irradiated into a halide oxide electrolyte, causing diffraction of X-rays by the regularly arranged atoms within the crystal structure of the halide oxide electrolyte. The diffraction signal is captured by a detector. The position, intensity, and width of the diffraction peaks in this XRD pattern can intuitively reflect the crystal structure information of the halide oxide electrolyte.

[0135] like Figure 2 As shown, the horizontal axis of the XRD pattern represents twice the diffraction angle (2θ, where θ is the diffraction angle), in degrees (°); the vertical axis represents the diffraction intensity, in relative intensity (any unit, au). Through Figure 2 It can be seen that the diffraction peaks are sharp and of high intensity, indicating that the halide oxide electrolytes prepared in Examples 1, 2, and 3 have good crystallinity. The positions of the diffraction peaks in Examples 1, 2, and 3 are similar to those of the core precursor (such as...). , The high peak matching degree of the standard crystalline structure (etc.) and the absence of peak shift or broadening due to surface fluorination treatment indicate that the formation of the coating layer (1-100nm) did not disrupt the crystalline structure of the core. Furthermore... Figure 2 The absence of obvious impurity peaks indicates that the fluorination reaction occurs only on the surface and no byproducts are generated. The diffraction characteristics of different examples 1, 2, and 3 are highly consistent, further proving that this process can stably prepare core-shell structured halide electrolytes, laying the structural foundation for halide electrolytes to possess both high ionic conductivity and high ionic stability.

[0136] Figure 3 The application performance diagram for Embodiment 2 provided in this application. For example... Figure 3 As shown, the horizontal axis represents the number of cycles, the left vertical axis represents the capacity in mAh / g, and the right vertical axis represents the coulombic efficiency in %. Gray dots represent charging capacity, blue dots represent discharging capacity, and green dots represent coulombic efficiency.

[0137] from Figure 3As can be seen, the battery in Example 2 maintained a discharge capacity retention of 81.9% after 550 cycles, demonstrating excellent cyclic ion stability. Although the discharge capacity decreased with cycling, the trend was gradual, indicating a high degree of matching between charge and discharge capacities. Furthermore, the coulombic efficiency remained above 98% for a long period, often approaching 100%, and the charge-discharge reversibility was excellent. This fully verifies that the halide oxide electrolyte in this application can effectively adapt to electrode reactions and exhibits strong interfacial ion stability, providing reliable support for the long-cycle performance and high energy efficiency of all-solid-state batteries, highlighting its outstanding advantages in battery applications.

[0138] This application also provides a solid-state battery, including a positive electrode, a negative electrode, and a halide oxide electrolyte. The halide oxide electrolyte is the halide oxide electrolyte proposed in any of the above-described halide oxide electrolyte embodiments, or a halide oxide electrolyte prepared by any of the above-described halide oxide electrolyte preparation method embodiments.

[0139] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A halide oxide electrolyte, characterized in that, Comprising: A core and a coating layer covering the surface of the core; The core is crystalline and has the general chemical formula xLi₂O-TaM₅, while the coating layer has the general chemical formula Li. a TaO b M c-d F d ; Where M is at least one of Cl, Br, and I, the value range of x is 0.1 ≤ x ≤ 3, the value range of a is 0.2 ≤ a ≤ 6, the value range of b is 0.1 < b ≤ 3, the value range of c is 1 ≤ c < 5, and the value range of d is 0 < d ≤ 4.

2. The halide oxide electrolyte according to claim 1, characterized in that, The value range of x is 0.2 ≤ x ≤ 0.8, the value range of a is 1 ≤ a ≤ 4, the value range of b is 0.5 < b ≤ 2, the value range of c is 2 ≤ c ≤ 4.4, and the value range of d is 0.6 ≤ d ≤ 3.

3. The halide oxide electrolyte according to claim 1 or 2, characterized in that, The thickness of the coating layer is 1 - 100 nm.

4. The halide oxide electrolyte according to claim 1 or 2, characterized in that, The median particle size of the oxychloride electrolyte is 0.05 - 100 μm.

5. A method for preparing a halide oxide electrolyte, characterized in that, The preparation method of the oxychloride electrolyte is used to prepare the oxychloride electrolyte according to any one of claims 1 - 4. The preparation method of the oxychloride electrolyte includes: Weigh raw materials according to the components and molar ratios shown in the chemical general formula of the core of the oxychloride electrolyte; Mix the raw materials to generate a precursor mixture; Perform a first heat treatment on the precursor mixture in an inert atmosphere to obtain a crystalline core precursor; Perform surface fluorination treatment on the crystalline core precursor to obtain the oxychloride electrolyte.

6. The method for preparing halide oxide electrolyte according to claim 5, characterized in that, The performing surface fluorination treatment on the crystalline core precursor to obtain the oxychloride electrolyte includes: Perform a second heat treatment on the crystalline core precursor in a fluorine-containing atmosphere to obtain the oxychloride electrolyte.

7. The method for preparing halide oxide electrolyte according to claim 6, characterized in that, The fluorine-containing atmosphere includes fluorine gas and / or HF gas.

8. The method for preparing halide oxide electrolyte according to any one of claims 5-7, characterized in that, The temperature of the first heat treatment is 80 - 400 °C, and / or the duration is 1 - 30 h.

9. The method for preparing halide oxide electrolyte according to claim 6 or 7, characterized in that, The temperature of the second heat treatment is 100 - 220 °C, and / or the duration is 1 - 100 min.

10. A solid-state battery, characterized in that, Comprising: A positive electrode, a negative electrode, and an oxychloride electrolyte; The oxychloride electrolyte is the oxychloride electrolyte according to any one of claims 1 - 4, or the oxychloride electrolyte prepared by the preparation method according to any one of claims 5 - 9.

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