Preparation method of halide electrolyte and solid-state battery

Abstract

The embodiment of the invention provides a preparation method of a halide electrolyte and a solid-state battery, and the method comprises the following steps: weighing raw materials according to the components shown in the chemical general formula of the halide electrolyte and the molar ratio, and then mixing the raw materials to obtain first precursor powder; then pre-sintering the first precursor powder in an inert atmosphere to obtain a first reactant; and finally, carrying out heat treatment on the first reactant in an inert atmosphere to obtain the halide electrolyte. The method is used for achieving the technical effect of improving the ionic conductivity of the prepared halide electrolyte.

Description

Technical Field

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

[0002] Halide solid electrolytes are becoming a new research hotspot currently due to their key characteristics such as high ionic conductivity, good deformation ability, and excellent electrochemical oxidation stability.

[0003] Currently, mainly the precursor powder is first prepared by mechanical ball milling, and then the obtained halide solid electrolyte can be obtained through annealing treatment. However, the ionic conductivity of the halide electrolyte prepared by the above method is relatively low. Summary of the Invention

[0004] Embodiments of this application provide a preparation method of a halide electrolyte and a solid-state battery, so as to achieve the technical effect of improving the ionic conductivity of the prepared halide electrolyte.

[0005] In a first aspect, embodiments of this application provide a halide electrolyte, and the chemical general formula of the halide electrolyte is Li a MO b X c ;

[0006] where M is at least one of Hf, Zr, Nb, Ta, and Ti, X is at least one of Cl, Br, and I, the value range of a is 0.1 ≤ a ≤ 5, the value range of b is 0 < b ≤ 2, and the value range of c is 2 ≤ c ≤ 6.

[0007] In a possible implementation manner, the value range of a is 1 ≤ a ≤ 3.5, the value range of b is 0 ≤ b ≤ 1.5, and the value range of c is 4.5 ≤ c ≤ 5.5.

[0008] In a second aspect, embodiments of this application provide a preparation method of a halide electrolyte, which is used to prepare the halide electrolyte as shown in the first aspect and / or various possible implementation manners of the first aspect. The preparation method includes:

[0009] Weigh raw materials according to the components and molar ratios shown in the chemical general formula of the halide electrolyte;

[0010] Mix the raw materials to obtain a first precursor powder;

[0011] Pre-calcine the first precursor powder in an inert atmosphere to obtain a first reactant;

[0012] Heat-treat the first reactant in an inert atmosphere to obtain the halide electrolyte.

[0013] In one possible implementation, the step of heat-treating the first reactant in an inert atmosphere to obtain the halide electrolyte comprises:

[0014] The first reactant is ground to obtain the ground first reactant;

[0015] The ground first reactant was heat-treated in an inert atmosphere to obtain the halide electrolyte.

[0016] In one possible implementation, the pre-firing temperature of the pre-firing treatment is 150-350°C.

[0017] In one possible implementation, the sintering temperature of the heat treatment is 150-350°C, and the pre-sintering temperature is lower than the sintering temperature.

[0018] In one possible implementation, the pre-firing time of the pre-firing treatment is 1-40 hours.

[0019] In one possible implementation, the sintering time of the heat treatment is 1-40 hours.

[0020] In one possible implementation, the gas in the inert atmosphere is at least one of argon, nitrogen, and helium.

[0021] Thirdly, embodiments of this application provide a solid-state battery, including: a positive electrode, a negative electrode, and a halide electrolyte;

[0022] 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.

[0023] The present application provides a method for preparing a halide electrolyte and a solid-state battery. The method includes: first, weighing raw materials according to the composition and molar ratio shown in the general chemical formula of the halide electrolyte; then mixing the raw materials to obtain a first precursor powder; then pre-calcining the first precursor powder in an inert atmosphere to obtain a first reactant; and finally heat-treating the first reactant in an inert atmosphere to obtain the halide electrolyte. In this technical solution, by adding a pre-calcination treatment before heat treatment, the metal element (Ta / Nb) is driven to fully combine with the halogen / oxygen source to form a metal halide oxide mesophase. This metal halide oxide mesophase has a one-dimensional, disordered orientation. Anionic chains. The disorder of this anionic sublattice induces a disordered distribution of multiple equivalent sites in the lithium-ion sublattice, thereby lowering the energy barrier for lithium-ion migration and effectively improving the ionic conductivity of the halide electrolyte. Simultaneously, this technical solution simplifies the process by eliminating the need for high-energy ball milling, improving operability, reducing preparation costs, and facilitating mass production, making it suitable for industrial manufacturing. Attached Figure Description

[0024] 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.

[0025] Figure 1 This is a schematic flowchart illustrating the preparation method of the halide electrolyte provided in this application.

[0026] The accompanying drawings have illustrated 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 specific embodiments. Detailed Implementation

[0027] 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.

[0028] First, the application background of this application will be explained:

[0029] Among the mainstream inorganic solid electrolyte materials currently available, they are mainly classified into oxide, sulfide, and halide systems based on the type of anion. While oxide systems exhibit good electrochemical oxidation stability, their rigid structure leads to poor electrode interface contact, typically requiring high-temperature processing or immersion in liquid electrolytes to improve assembly. Sulfide systems possess high ionic conductivity and excellent deformation capability; however, they are highly sensitive to environmental humidity and prone to harmful hydrolysis reactions that cause a sharp drop in ionic conductivity. Furthermore, their insufficient oxidation stability limits their application in high-voltage cathodes. In contrast, halide solid electrolytes, with their high ionic conductivity, good deformation capability, and excellent electrochemical oxidation stability, are becoming a new research hotspot.

[0030] Research on halide solid electrolytes has a long history and a rich technological foundation. Its evolution can be traced back to 1930, when researchers first discovered that lithium halides (LiX, X=F, Cl, Br, I) possess lithium-ion conductivity. Subsequently, in the late 1960s, LiX solid electrolytes were developed for use in thin-film all-solid-state batteries. Although the halides developed in this stage did not perform well in terms of room-temperature ionic conductivity (…),… However, they are important for a deeper understanding of halides. The diffusion mechanism and abundant halide structural prototypes are of great significance. Until 2018, [the following text appears to be incomplete and requires further context: "possessing excellent ionic conductivity and electrochemical stability..."] (LYC) and The emergence of (LYB) halide solid electrolytes has reignited research enthusiasm in this field.

[0031] High ionic conductivity halide electrolytes can be mainly divided into four types: Type (M represents Zr, In, rare earth ions, etc., X represents Cl, Br), type, Types (X is Cl, Br, O, etc., M is Nb, Ta) and amorphous halides. Among them, The halogen anion arrangement of the material exhibits a hexagonal close-packed (hcp) or cubic close-packed (ccp) structure. The latter can achieve rapid lithium-ion conduction in all three directions (a, b, and c), and its overall ionic conductivity is usually higher than that of the hcp type, reaching more than 5 mS / cm. The anion arrangement in the crystal structure exhibits a unique non-close-packed form, possessing abundant one-dimensional channels and a large number of additional channels. By occupying the site, its ionic conductivity can reach over 1 mS / cm. The type structure has a highly oriented disordered one-dimensional structure. Anionic chains promote multiple... Site disordering effectively reduces The migration energy barrier allows for the development of ultra-high ionic conductivity (>10 mS / cm) comparable to that of liquid electrolytes. For example, LTOC and LNOC solid electrolytes with ionic conductivity as high as 12.4 mS / cm and 10.4 mS / cm, respectively, have been successfully prepared by mechanical ball milling. Their performance is far superior to that of traditional halide solid electrolytes, while inheriting the high oxidation stability and good deformability of halide systems.

[0032] However, this method requires the preparation of precursor powder through mechanical ball milling, followed by annealing to obtain the final product. This is because halide electrolytes (such as LTOC / LNOC) rely on specific elements (such as Ta / Nb) to construct a highly oriented, disordered one-dimensional structure. The anionic chain structure, with its unique crystal arrangement, effectively lowers the lithium-ion migration barrier, thus achieving ultra-high ionic conductivity. However, elements such as Ta and Nb have low melting and boiling points and are prone to volatilization during annealing, leading to changes in the composition of the halide electrolyte. The absence of key metal elements causes the collapse or distortion of the disordered anionic chain structure necessary to maintain high ionic conductivity; furthermore, the vacancy defects formed after the escape of volatile elements increase the lithium-ion migration barrier and may induce unfavorable secondary phase formation. These two factors obstruct the lithium-ion transport channels within the halide electrolyte, making it difficult to achieve ionic conductivity above 8 mS / cm.

[0033] In summary, existing technologies suffer from the problem of low ionic conductivity in halide electrolytes.

[0034] Based on the technical problems existing in the prior art, the technical concept of this application is as follows: The low ionic conductivity of existing halide electrolytes is mainly due to the thermal instability of elements such as Ta and Nb at annealing temperatures. If the raw materials are pre-calcined at an environment close to their melting point before annealing, a mild solid-phase reaction drives the metal elements (Ta / Nb) to fully combine with the halogen / oxygen source, forming in situ a metal halide oxide mesophase with significantly improved thermal stability (such as...). , This allows for the effective binding of volatile elements during subsequent heat treatment, thereby improving the ionic conductivity of the prepared halide electrolyte.

[0035] 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.

[0036] Figure 1 The schematic diagram of the preparation method of the halide electrolyte provided in this application is shown below. Figure 1 As shown, the method includes:

[0037] S11. Weigh the raw materials according to the composition and molar ratio shown in the general chemical formula of halide electrolytes.

[0038] Among them, the general chemical formula of halide electrolytes is Li a MO b X c .

[0039] Among them, M is at least one of Hf, Zr, Nb, Ta, and Ti, X is at least one of Cl, Br, and I, the value range of a is 0.1 ≤ a ≤ 5, the value range of b is 0 < b ≤ 2, and the value range of c is 2 ≤ c ≤ 6.

[0040] For example, M can be Nb and / or Ta, and X can be Cl and / or Br.

[0041] It should be understood that the values of a, b, and c are determined by the chemical valences of the M element and the X element.

[0042] It should be understood that compared with conventional halides (such as Li3YCl6), in the halide electrolyte of this embodiment, partial substitution of halogen ( ) breaks the [MX6] octahedral symmetry and forms a one-dimensional orientation-disordered anionic chain (such as ), which promotes to present a high-entropy disordered occupancy state, significantly reducing the migration energy barrier between adjacent sites, and thus increasing the ionic conductivity. Moreover, the high electronegativity of results in the shortening of the M-O bond and the elongation of the M-X bond, triggering low-frequency anharmonic phonon vibrations in the lattice, and its strong coupling effect with the

[0043] migration provides additional kinetic energy to compensate for the migration barrier, further increasing the ionic conductivity. a MO b X c can be Li2TaOCl5 (M is Ta, X is Cl, a is 2, b is 1, c is 5), LiTaO 0.5 Cl5 (M is Ta, X is Cl, a is 1, b is 0.5, c is 5), Li3TaO 1.5 Cl5 (M is Ta, X is Cl, a is 3, b is 1.5, c is 5), etc.

[0044] It should be understood that in addition to the above examples, according to different selections of M, X, a, b, and c within their respective value ranges, the specific chemical formula of the halide electrolyte can also be Li4TaO2Cl5, Li2NbOCl5, and Li3NbO 1.5 Cl5, etc., to meet the specific requirements of users in specific application scenarios.

[0045] Optionally, the value range of a is 1 ≤ a ≤ 3.5, the value range of b is 0 ≤ b ≤ 1.5, and the value range of c is 4.5 ≤ c ≤ 5.5.

[0046] It should be understood that the raw materials weighed in this step include Li element, M element, O element, and X element.

[0047] For example, when the chemical formula of the halide electrolyte is Li₂TaOCl₅, the raw materials weighed are Li₂O and TaCl₅, and the molar ratio of Li₂O to TaCl₅ is 1:1; when the chemical formula of the halide electrolyte is... The raw materials weighed are Li₂O and TaCl₅, and the molar ratio of Li₂O to TaCl₅ is 0.5:1; the chemical formula of the halide electrolyte is... The raw materials weighed are Li2O and TaCl5, and the molar ratio of Li2O to TaCl5 is 1.5:1.

[0048] Understandably, in addition to the specific molar ratios mentioned above, other raw material ratios can be obtained based on the different chemical formulas of the halide electrolyte, such as Li2O and TaCl5 as raw materials, with a Li2O:TaCl5 molar ratio of 2:1 (the chemical formula of the halide electrolyte is Li4TaO2Cl5), to meet the specific needs of users in specific application scenarios.

[0049] in, It is a white solid that readily absorbs moisture from the air. ; It is a pale yellow solid or white needle-like crystal, and is hygroscopic. Therefore, to ensure that the halide electrolyte is not contaminated or deteriorated during preparation, the entire process can be carried out under an inert atmosphere. That is, the raw materials can be weighed under an inert atmosphere.

[0050] 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.

[0051] Optionally, the raw materials for halide electrolytes can be weighed using a balance or other weighing tools.

[0052] S12. Mix the raw materials to obtain the first precursor powder.

[0053] 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 first precursor powder.

[0054] In another possible implementation, the weighed raw materials can be added to a planetary ball mill to mix them and obtain a first precursor powder.

[0055] In another possible implementation, the weighed raw materials can be added to a high-frequency vibration mill to mix them by vibration grinding to obtain the first precursor powder.

[0056] It should be understood that the raw materials can also be mixed by other mixing methods to improve the uniformity of the obtained first precursor powder. The embodiments of this application do not limit the specific mixing method.

[0057] 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.

[0058] Optional, the mixing time is 20 minutes to 1 hour.

[0059] It should be understood that mixing time refers to the duration required for mixing the raw materials.

[0060] S13. The first precursor powder is pre-calcined in an inert atmosphere to obtain the first reactant.

[0061] Pre-sintering treatment refers to the process of heating the precursor powder at medium and low temperatures before formal sintering. The purpose is to enable the raw materials to initially combine through preliminary physicochemical reactions, promote solid-state reactions between the raw materials, and generate a metal halide oxide intermediate phase to bind volatile elements in subsequent heat treatment.

[0062] Alternatively, the first precursor powder can be pre-calcined using equipment such as heat treatment furnaces, sintering furnaces, and rotary kilns.

[0063] Optionally, the pre-firing temperature of the pre-firing treatment is 150-350℃.

[0064] For example, the preheating temperature can be 150-350℃.

[0065] The pre-calcination temperature should be close to the melting point of the volatile elements in the first precursor powder. If the pre-calcination temperature is too high, the volatile elements in the first precursor powder will volatilize; if the pre-calcination temperature is also too high, the solid-phase diffusion during the pre-calcination process will be insufficient, preventing the first precursor powder from transforming into the mesophase and affecting the performance of the final halide electrolyte. When the pre-calcination temperature is close to the melting point of the volatile elements, the kinetic activity of the volatile elements can be maximized, intensifying atomic vibrations but not reaching the threshold for violent evaporation, resulting in the formation of a sintering neck without complete melting, thus ensuring the stability of the formed mesophase.

[0066] In other words, pre-firing treatment can induce a solid-phase reaction between the volatile element and other components before the volatile element begins to volatilize significantly, forming a stable intermediate phase. This effectively locks in the volatile component, reduces element loss in the subsequent high-temperature stage, and avoids compositional deviation and material porosity defects caused by premature volatilization.

[0067] It should be understood that when multiple volatile elements are present in the first precursor powder, the pre-calcination temperature can be increased in a gradient.

[0068] In other words, the above-mentioned pre-calcination treatment of the first precursor powder in an inert atmosphere to obtain the first reactant can be achieved by: determining the corresponding pre-calcination temperature based on at least one volatile element in the first precursor powder; then, pre-calcining the first precursor powder in an inert atmosphere according to at least one pre-calcination temperature in ascending order of pre-calcination temperature to obtain the first reactant.

[0069] For example, suppose the first precursor powder contains volatile element 1 and volatile element 2, with volatile element 1 having a melting point of melting point 1 and volatile element 2 having a melting point of melting point 2, where melting point 1 < melting point 2. Then, the first precursor powder can undergo a first-stage pre-calcination treatment at a temperature close to melting point 1 for a duration of 1; subsequently, a second-stage pre-calcination treatment can be performed at a temperature close to melting point 2 for a duration of 2, ultimately yielding the first reactant.

[0070] The sum of duration 1 and duration 2 is the pre-burning duration of the pre-burning treatment, which refers to the duration of the pre-burning treatment of the first precursor powder.

[0071] The pre-firing time for the pre-firing treatment is 1-40 hours.

[0072] For example, the preheating time is 1-30 hours.

[0073] It should be understood that the entire pre-calcination process needs to be carried out in an inert atmosphere to avoid the first precursor powder reacting with other components in the air.

[0074] The gas in the inert atmosphere is at least one of argon, nitrogen, and helium.

[0075] In practical applications, sufficient argon gas can be introduced into a sealed heat treatment furnace to completely expel the air. The first precursor powder is then placed in a crucible and placed in the heat treatment furnace for pre-calcination at the pre-calcination temperature until the pre-calcination time is reached.

[0076] S14. The first reactant is heat-treated in an inert atmosphere to obtain a halide electrolyte.

[0077] Alternatively, the first reactant can be heat-treated using equipment such as a heat treatment furnace, sintering furnace, or rotary kiln.

[0078] Among them, heat treatment can use thermal energy to drive the migration of matter between the particles of the first reactant, thereby expanding the contact points between the particles, gradually reducing or closing the gaps, and ultimately transforming the loose first reactant into a dense solid halide electrolyte.

[0079] It should be understood that heat treatment can be sintering.

[0080] In one possible implementation, the first reactant can be ground to obtain a ground first reactant; then the ground first reactant can be heat-treated in an inert atmosphere to obtain a halide electrolyte.

[0081] Since the first reactant is obtained through pre-calcination, it may have agglomeration issues. To ensure that the first reactant receives sufficient heat treatment, it can be ground before heat treatment to ensure the homogeneity of the ground first reactant.

[0082] Alternatively, the first reactant can be added to an agate mortar and ground using a dry grinding method to obtain the ground first reactant.

[0083] Optionally, the first reactant can be added to a planetary ball mill to grind it, thereby obtaining the ground first reactant.

[0084] Optionally, the first reactant can be added to a high-frequency vibration mill to grind it by vibration grinding to obtain the ground first reactant.

[0085] It should be understood that the first reactant can also be ground by other grinding methods to improve the uniformity of the ground first reactant. The embodiments of this application do not limit the specific grinding method.

[0086] The sintering temperature of the heat treatment is 150-350℃, and the pre-firing temperature is lower than the sintering temperature.

[0087] It should be understood that the sintering temperature of heat treatment refers to the temperature that needs to be maintained continuously during the heat treatment of the first reactant.

[0088] In practical applications, the pre-calcination stage is mainly for generating a metal halide oxide mesophase to bind volatile elements, while the heat treatment stage is mainly for achieving particle fusion and densification. Therefore, the temperature required for the heat treatment stage is higher than that required for the pre-calcination stage.

[0089] The sintering time for heat treatment is 1-40 hours.

[0090] It should be understood that the sintering time of heat treatment refers to the duration required for heat treatment of the first reactant.

[0091] For example, the sintering time for heat treatment is 1-30 hours.

[0092] It should be understood that the entire heat treatment needs to be carried out in an inert atmosphere to avoid the primary reactant reacting with other components in the air.

[0093] The method for preparing halide electrolytes provided in this application involves first weighing raw materials according to the composition and molar ratio shown in the general chemical formula of the halide electrolyte, then mixing the raw materials to obtain a first precursor powder. The first precursor powder is then pre-calcined in an inert atmosphere to obtain a first reactant. Finally, the first reactant is heat-treated in an inert atmosphere to obtain the halide electrolyte. In this technical solution, by adding a pre-calcination treatment before heat treatment, the metal elements (Ta / Nb) are driven to fully combine with the halogen / oxygen source to form a metal halide oxide mesophase. This metal halide oxide mesophase has a one-dimensional, disordered orientation. Anionic chains. The disorder of this anionic sublattice induces a disordered distribution of multiple equivalent sites in the lithium-ion sublattice, thereby lowering the energy barrier for lithium-ion migration and effectively improving the ionic conductivity of the halide electrolyte. Simultaneously, this technical solution simplifies the process by eliminating the need for high-energy ball milling, improving operability, reducing preparation costs, and facilitating mass production, making it suitable for industrial manufacturing.

[0094] The technical effects of this application will be illustrated below through several embodiments and comparative examples.

[0095] Example 1

[0096] Halogen electrolytes are prepared by the following steps:

[0097] Step (1): Weigh Li2O and TaCl5 according to the molar ratio of Li2O:TaCl5 of 1:1, add them to an agate mortar, and mix them for 30 minutes using a dry grinding method to obtain the first precursor powder.

[0098] Step (2): In a nitrogen atmosphere, the first precursor powder obtained in step (1) is pre-calcined in a heat treatment furnace at a pre-calcination temperature of 230°C for 3 hours to obtain the first reactant.

[0099] Step (3): Add the first reactant obtained in step (2) into an agate mortar and grind it for a certain period of time to mix it thoroughly, so as to obtain the ground first reactant.

[0100] Step (4): The first reactant after grinding is sintered in a nitrogen atmosphere at a sintering temperature of 250°C for 3 hours to obtain a halide solid electrolyte with a composition of Li2TaOCl5.

[0101] Example 2

[0102] The difference from Example 1 is that the pre-firing temperature in step (2) is 220°C;

[0103] Example 3

[0104] The difference from Example 1 is that the pre-firing temperature in step (2) is 240°C;

[0105] Example 4

[0106] The difference from Example 1 is that the pre-firing time in step (2) is 2 hours and the sintering time in step (3) is 4 hours.

[0107] Example 5

[0108] The difference from Example 1 is that the pre-firing time in step (2) is 4 hours and the sintering time in step (3) is 2 hours.

[0109] Example 6

[0110] The difference from Example 1 is that the second reactant has the chemical composition of LiTaO. 0.5 Cl5, step (1) weigh Li2O and TaCl5 according to the molar ratio of Li2O:TaCl5 of 0.5:1.

[0111] Example 7

[0112] The difference from Example 1 is that the chemical composition of the second reactant is Li3TaO. 1.5 Cl5, the corresponding step (1) weigh Li2O:TaCl5 according to the molar ratio of Li2O:TaCl5 of 1.5:1.

[0113] Example 8

[0114] The difference from Example 1 is that the chemical composition of the second reactant is Li4TaO2Cl5, and the corresponding step (1) is to weigh Li2O and TaCl5 according to the molar ratio of Li2O:TaCl5 of 2:1.

[0115] Example 9

[0116] The difference from Example 1 is that the chemical composition of the second reactant is Li2NbOCl5, and the corresponding step (1) is to weigh Li2O and NbCl5 according to the molar ratio of Li2O:NbCl5 of 1:1.

[0117] Example 10

[0118] The difference from Example 1 is that the chemical composition of the second reactant is Li3NbO. 1.5Cl5, the corresponding step (1) weigh Li2O and NbCl5 according to the molar ratio of Li2O:NbCl5 of 1.5:1.

[0119] Comparative Example 1

[0120] Halogen electrolytes are prepared by the following steps:

[0121] Step (A): Weigh Li2O and TaCl5 according to a molar ratio of Li2O:TaCl5 of 1:1, add them to an agate mortar, and mix them by dry grinding for 30 minutes to obtain the first precursor powder.

[0122] Step (B): The ground first reactant is sintered in a nitrogen atmosphere at a sintering temperature of 250°C for 6 hours to obtain a halide solid electrolyte with a composition of Li2TaOCl5.

[0123] Comparative Example 2

[0124] The difference from Comparative Example 1 is that the chemical formula of the first reactant is Li3TaO. 1.5 Cl5, the corresponding step (A) is to weigh Li2O:TaCl5 according to the molar ratio of Li2O:TaCl5 of 1.5:1.

[0125] Comparative Example 3

[0126] The difference from Comparative Example 1 is that the chemical formula of the first reactant is Li2NbOCl5, and the corresponding step (A) is to weigh Li2O and NbCl5 according to a molar ratio of Li2O:NbCl5 of 1:1.

[0127] Test case

[0128] Ionic conductivity test: 100 mg of halide electrolyte powder was weighed and placed inside a pressure molding mold. A pressure of 300 MPa was applied to the halide electrolyte powder for molding to obtain the molded halide electrolyte. Under pressure, the impedance value of the molded halide electrolyte was measured at room temperature (25 °C) using electrochemical impedance spectroscopy. The real value of the impedance at the measurement point with the smallest absolute value of the phase of multiple impedances was taken as the resistance of the molded halide electrolyte to solid electrolyte (RSE) relative to ion conduction.

[0129] Then, the ionic conductivity is calculated based on the formula σ=(RSE×S / t)-1. Here, σ is the ionic conductivity, RSE is the solid electrolyte resistance of the formed halide electrolyte, S is the surface area of ​​the formed halide electrolyte, and t is the thickness of the formed halide electrolyte.

[0130] For example, the ionic conductivity of each embodiment and each comparative example is shown in Table 1.

[0131] Table 1. Ionic conductivity of each embodiment and comparative example

[0132]

[0133] Referring to Table 1, comparing Example 1 with Comparative Example 1, Example 7 with Comparative Example 1, and Example 9 with Comparative Example 1, it can be seen that pre-calcining the raw materials before sintering can effectively improve the ionic conductivity of the prepared halide electrolyte.

[0134] This application also provides a solid-state battery, including a positive electrode, a negative electrode, and a halide electrolyte. The halide electrolyte is the halide electrolyte proposed in any of the above-described halide electrolyte examples, or a halide electrolyte prepared by any of the above-described halide electrolyte preparation method examples.

[0135] 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 method for preparing a halide electrolyte, characterized in that, include: Weigh the raw materials according to the composition and molar ratio shown in the general chemical formula of the halide electrolyte; The raw materials are mixed to obtain a first precursor powder; The first precursor powder was pre-calcined in an inert atmosphere to obtain the first reactant. The first reactant was heat-treated in an inert atmosphere to obtain a halide electrolyte; Among them, the chemical general formula of the halide electrolyte is Li a MO b X c , M is at least one of Hf, Zr, Nb, Ta and Ti, X is at least one of Cl, Br and I, the value range of a is 0.1 ≤ a ≤ 5, the value range of b is 0 < b ≤ 2, and the value range of c is 2 ≤ c ≤ 6; The step of pre-calcining the first precursor powder in an inert atmosphere to obtain the first reactant includes: The corresponding pre-calcination temperature is determined based on at least one volatile element in the first precursor powder; The first precursor powder is pre-calcined in the inert atmosphere at at least one pre-calcination temperature, in order of increasing pre-calcination temperature, to obtain the first reactant.

2. The method for preparing halide electrolyte according to claim 1, characterized in that, The range of values ​​for a is 1 ≤ a ≤ 3.5, the range of values ​​for b is 0 ≤ b ≤ 1.5, and the range of values ​​for c is 4.5 ≤ c ≤ 5.

5.

3. The method for preparing halide electrolytes according to claim 1, characterized in that, The step of heat-treating the first reactant in an inert atmosphere to obtain a halide electrolyte includes: The first reactant is ground to obtain the ground first reactant; The ground first reactant was heat-treated in an inert atmosphere to obtain the halide electrolyte.

4. The method for preparing halide electrolytes according to any one of claims 1-3, characterized in that, The pre-firing temperature of the pre-firing treatment is 150-350℃.

5. The method for preparing halide electrolytes according to any one of claims 1-3, characterized in that, The sintering temperature of the heat treatment is 150-350℃, and the pre-firing temperature is lower than the sintering temperature.

6. The method for preparing halide electrolytes according to any one of claims 1-3, characterized in that, The pre-firing time for the pre-firing treatment is 1-40 hours.

7. The method for preparing halide electrolytes according to any one of claims 1-3, characterized in that, The sintering time for the heat treatment is 1-40 hours.

8. The method for preparing the halide electrolyte according to any one of claims 1-3, characterized in that, The gas in the inert atmosphere is at least one of argon, nitrogen, and helium.

9. A solid-state battery, characterized in that, include: Positive electrode, negative electrode, and halide electrolyte; The halide electrolyte is a halide electrolyte prepared by the method for preparing halide electrolytes as described in any one of claims 1-8.

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