Solid electrolyte, its preparation method, use and electrochemical device

Abstract

The present invention provides a solid electrolyte, a method for preparing the same, its use, and an electrochemical device. The preparation method includes performing ion exchange of molecular sieve-Na in an acidic solution so that the cations in the pores of molecular sieve-Na are exchanged with protons, forming molecular sieve-H by evaporating water molecules after washing and drying, forming OH by bonding oxygen and protons in the aluminum-oxygen tetrahedron of molecular sieve-H, obtaining molecular sieve-X1 by exchanging OH in molecular sieve-H with halogen X1 (X1 = F, Cl, Br, I) through a halogenation reaction, and firing molecular sieve-X1 and molten AX2 to obtain a solid electrolyte. The pH of the acidic solution is 1.2 < pH < 2.1. AX2 includes an alkali metal halide and / or an alkali metal chalcogenide. The firing temperature is 300 to 500 °C. The solid electrolyte has high ionic conductivity and can be used alone as a solid electrolyte.

Description

[Technical Field]

[0001] The present invention relates to a solid electrolyte and to a method for preparing, using and using the same in an electrochemical device. [Background technology]

[0002] In recent years, new energy vehicles, typified by electric vehicles, have taken the automobile market by storm. The performance of power batteries, a core component of electric vehicles, has a significant impact on the actual usage performance of electric vehicles. The chemical system of power batteries currently commercially available is lithium-ion batteries. Compared to conventional liquid electrolyte-based lithium-ion batteries, solid-state lithium batteries use a solid electrolyte instead of a liquid electrolyte and separator, making the battery thinner and more compact. This improves the energy density of the battery and also improves its safety.

[0003] All-solid-state batteries consist of a positive electrode, a solid electrolyte, and a negative electrode. In recent years, molecular sieves have also been used as solid electrolytes in battery systems. However, due to their low ionic conductivity, molecular sieves are generally difficult to use as solid electrolytes. Therefore, they are often used in combination with polymer electrolytes or ionic liquids.

[0004] For example, Patent Document 1 discloses a composite solid electrolyte, a lithium battery, and a preparation method. In Patent Document 1, a molecular sieve is placed in a lithium salt solution and ion-exchanged to obtain a modified molecular sieve. A polymer, a lithium salt, the modified molecular sieve, and a solvent are then mixed to obtain a composite polymer electrolyte. The composite polymer electrolyte is then coated onto a porous substrate membrane to obtain a composite solid electrolyte. This solves the problems of conventional lithium batteries, such as poor mechanical strength and low lithium ion conductivity.

[0005] Patent Document 2 discloses a molecular sieve-supported sodium ion solid electrolyte and its preparation method and use. In Patent Document 2, the ionic conductivity of the solid electrolyte is improved by preparing the solid electrolyte using a molecular sieve, an ionic liquid, and a sodium salt as raw materials.

[0006] In the above two patent documents, a solid electrolyte is prepared by combining a molecular sieve with a polymer electrolyte or an ionic liquid. However, such a composite solid electrolyte is unstable in air and easily absorbs water, which makes it difficult to transport and store.

[0007] Therefore, the development of a molecular sieve-type solid electrolyte that not only has high ionic conductivity but can also be used alone has become a challenge for those skilled in the art. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Chinese Patent Application Publication No. 116666737 [Patent Document 2] Chinese Patent Application Publication No. 111755734 Summary of the Invention [Problem to be solved by the invention]

[0009] The technical problem to be solved by the present invention is to overcome the drawbacks of the prior art that molecular sieves have low ionic conductivity and cannot be used alone as a solid electrolyte, and to provide a solid electrolyte, a method for preparing the same, use thereof, and an electrochemical device. The solid electrolyte prepared by the present invention has high ionic conductivity and can be used alone as a solid electrolyte.

[0010] When molecular sieves are used as solid electrolytes, they typically suffer from low ionic conductivity. Conventional techniques generally improve the ionic conductivity of molecular sieves by combining them with polymer electrolytes or ionic liquids or by incorporating cations into the molecular sieve. However, oxygen anions in the molecular sieve easily bind to the metal cations in the molecular sieve, hindering cation migration and reducing ionic conductivity. In contrast, in the present invention, the metal cations in the molecular sieve are exchanged for protons, and the molecular sieve is dried. The water molecules in the molecular sieve then evaporate, causing oxygen in the aluminum-oxygen tetrahedra in the molecular sieve to combine with protons to form OH. Next, the OH in the molecular sieve is exchanged for halogen by a halogenation reaction, reducing the concentration of oxygen anions in the molecular sieve and facilitating the migration of metal cations. Furthermore, to further improve the migration rate of metal cations, the molecular sieve obtained after the halogenation reaction is calcined with a molten alkali metal salt, thereby incorporating the cations and anions in the alkali metal salt into the molecular sieve. The anions in the alkali metal salt line the edges of the pore channels of the molecular sieve, allowing the alkali metal cations to move more freely through the channels, further increasing the rate of movement of the alkali metal cations within the channels and thereby improving the ionic conductivity of the solid electrolyte. [Means for solving the problem]

[0011] The present invention solves the above technical problems by the following technical means.

[0012] The present invention provides a method for preparing a solid electrolyte. The method includes the steps of: performing ion exchange of molecular sieve-Na in an acidic solution so that the cations in the pore channels of the molecular sieve-Na are exchanged with protons; after washing and drying, water molecules evaporate to form molecular sieve-H, and oxygen and protons in the aluminum-oxygen tetrahedron of the molecular sieve-H combine to form OH; through a halogenation reaction, OH in the molecular sieve-H is exchanged with halogen X1 (X1 = F, Cl, Br, I) to obtain molecular sieve-X1; and performing firing on the molecular sieve-X1 and molten AX2 so that the cations and anions in the AX2 enter into the pore channels of the molecular sieve-X1 to obtain the solid electrolyte AX2@molecular sieve-X1.

[0013] The pH of the acidic solution is 1.2 < pH < 2.1. The AX2 includes an alkali metal halide and / or an alkali metal chalcogenide. The firing temperature is 300 - 500 °C.

[0014] In the present invention, the preparation method preferably includes the steps of: performing ion exchange of molecular sieve-Na in an acidic solution, and after washing and drying, forming molecular sieve-H; subjecting the molecular sieve-H to a halogenation reaction to obtain molecular sieve-X1; and performing firing on the molecular sieve-X1 and molten AX2 to obtain the solid electrolyte AX2@molecular sieve-X1.

[0015] The pH of the acidic solution is 1.2 < pH < 2.1. The AX2 includes an alkali metal halide and / or an alkali metal chalcogenide. The firing temperature is 300 - 500 °C.

[0016] In the present invention, in the process of performing ion exchange in an acidic solution, the pH in the acidic solution has an important influence on the structure of the molecular sieve and the degree to which cations in the pores of the molecular sieve are exchanged with protons. When the pH of the acid used is 1.2 < pH < 2.2, the degree to which cations in the pores of the molecular sieve are exchanged with protons becomes higher, which is more advantageous for the subsequent entry of alkali metal salts.

[0017] In the present invention, in the process of the halogenation reaction, usually, monovalent halogen ions have an ionic potential (Ф = Z / r) lower than that of divalent oxygen, so the binding force with alkali metal ions becomes weak, contributing to the rapid transport of alkali metal ions between pores. 2-valent oxygen, contributing to the rapid transport of alkali metal ions between pores.

[0018] In the present invention, the pore diameter of the molecular sieve-Na may be 0.5 to 100 nm.

[0019] In the present invention, the type of the molecular sieve-Na may be one or more of X-type, A-type, Y-type, and ZSM-5 type, for example, X-type.

[0020] In the present invention, the molecular sieve-Na means a molecular sieve in which the cation is a Na ion.

[0021] In a specific embodiment, the type of the molecular sieve-Na is a NaY-type molecular sieve.

[0022] In the present invention, the mass fraction of Na2O in the molecular sieve-Na may be 8 to 15%, for example, 12.5%. The mass fraction means the percentage of the mass of Na2O in the mass of the molecular sieve.

[0023] In the present invention, the silicon / aluminum ratio in the molecular sieve-Na may be 0.9 to 5. The silicon / aluminum ratio means the molar ratio of SiO2 / Al2O3.

[0024] In the present invention, the pH of the acidic solution is preferably 1.8 < pH < 2.1, for example, 2.0.

[0025] In the present invention, the acidic solution may contain one or more of acetic acid, hydrochloric acid, benzoic acid, formic acid, and salicylic acid, for example, acetic acid.

[0026] In the present invention, the concentration of the acidic solution may be 1.5 to 4 mol / L, for example, 2 mol / L or 3 mol / L.

[0027] In a specific embodiment, the acidic solution is 2 mol / L acetic acid.

[0028] In the present invention, the ratio of the mass of the molecular sieve - Na to the volume of the acidic solution may be 1:(40 - 80) g / mL, for example, 1:50 g / mL.

[0029] In the present invention, the ion exchange is generally carried out at room temperature.

[0030] In the present invention, the time of the ion exchange may be 8 to 20 h, for example,  12 h.

[0031] In the present invention, the ion exchange is preferably carried out under stirring. The rotation speed during the stirring may be 200 - 800 rpm, for example, 400 rpm.

[0032] In the present invention, the washing is generally carried out using deionized water. The washing method may be suction filtration. The number of washing times is generally 3 or more.

[0033] In the present invention, the temperature during drying may be 40 - 80 °C, for example, 60 °C. The drying time may be 2 - 8 h, for example, 3 h. The drying is generally carried out in an oven.

[0034] In the present invention, the substance containing the halogen X1 used in the halogenation reaction may be a simple halogen or an ammonium salt. The simple halogen may be, for example, liquid bromine, chlorine gas, or iodine. When the halogen X1 is F, the ammonium salt is ammonium fluoride or ammonium hydrogen fluoride.

[0035] In the present invention, the halogenation reaction method can be flexibly selected depending on the form of the substance containing the halogen X1. For example, when the substance containing the halogen X1 is a halogen gas alone, chemical vapor deposition of the molecular sieve-H and the halogen gas alone can be performed. Furthermore, when the substance containing the halogen X1 is a liquid halogen, a solid halogen, or an ammonium salt, the molecular sieve-H and the substance containing the halogen X1 can be subjected to a solvothermal reaction.

[0036] The solvothermal reaction is generally carried out in a reaction vessel. The solvent selected in the solvothermal process may be deionized water and / or an alcoholic solvent. The alcoholic solvent may be ethanol. The temperature of the solvothermal reaction may be 110 to 150°C, for example, 130°C. The time period for the solvothermal reaction may be 8 to 16 hours, for example, 12 hours.

[0037] In a specific embodiment, the halogenation reaction includes reacting a mixture of the molecular sieve-H, liquid bromine, and ethanol in a reaction vessel. The reaction temperature is 130°C, and the reaction time is 12 hours. The ratio of the mass of the molecular sieve-Na to the volume of the liquid bromine may be (1.2 to 1.6) mg / μL, for example, 1.43 mg / μL. The ratio of the volume of the liquid bromine to the ethanol may be 0.001 to 0.2, for example, 0.007.

[0038] In the present invention, the cation of AX2 preferably includes Li ions and / or K ions.

[0039] In the present invention, the anion of AX2 includes one or more of Cl ions, Br ions, S ions, and Se ions.

[0040] In the present invention, the alkali metal halide may be an alkali metal chloride or an alkali metal bromide.

[0041] In the present invention, the alkali metal chalcogenide may be an alkali metal sulfide or an alkali metal selenide.

[0042] In the present invention, AX2 may be a mixed salt of lithium chloride and potassium chloride, a mixed salt of lithium bromide and potassium bromide, or a mixed salt of lithium chloride and lithium nitrate, and is preferably a mixed salt of lithium chloride and potassium chloride.

[0043] In a specific embodiment, said AX2 is a mixed salt of lithium chloride and potassium chloride.

[0044] When AX2 is a mixed salt of lithium chloride and potassium chloride, the ratio of the amount of lithium chloride to the amount of potassium chloride may be 1:(0.5 to 1.5), preferably 1:(0.8 to 1.2), for example, 1:0.5, 1:1, or 1:1.5.

[0045] In a specific embodiment, AX2 is a mixed salt of lithium bromide and potassium bromide. .

[0046] When AX2 is a mixed salt of lithium bromide and potassium bromide, the ratio of the amount of lithium bromide to the amount of potassium bromide may be 1:(0.5 to 1.5), for example, 1:1.

[0047] In a specific embodiment, the AX2 is a mixed salt of lithium chloride and lithium nitrate.

[0048] When AX2 is a mixed salt of lithium chloride and lithium nitrate, the ratio of the amount of substance of the lithium chloride to the amount of substance of the lithium nitrate may be 1:(0.5 to 1.5), for example, 1:1.

[0049] In the present invention, the ratio of the amount of substance of the AX2 to the amount of substance of Na2O in the molecular sieve is preferably (5 to 15):1, for example, 4:1, 8:1, 9:1, 10:1 or 12:1.

[0050] In the present invention, the method for preparing the melted AX2 may include melting AX2 with a heat gun, or heating and melting AX2 in a muffle furnace or a tubular furnace.

[0051] In the present invention, the calcination is generally carried out in an air atmosphere, and the calcination is generally carried out in a muffle furnace.

[0052] In the present invention, the firing temperature may be 350 to 500°C, for example, 380°C, 400°C, or 450°C.

[0053] In the present invention, the baking time may be 8 to 20 hours, for example, 10 hours or 15 hours.

[0054] In the present invention, the rate of temperature rise up to the firing temperature may be 0.5 to 10°C / min, preferably 1 to 5°C / min, for example 3°C / min.

[0055] In the present invention, it is preferable to further carry out washing and drying after the firing.

[0056] The washing is generally carried out using deionized water, and the number of washing steps is generally three or more.

[0057] The temperature during the drying may be 40 to 80° C., for example, 60° C. The drying time may be 2 to 8 hours, for example, 3 hours. The drying is generally performed in an oven.

[0058] The present invention further provides a solid electrolyte prepared by the above-mentioned method for preparing a solid electrolyte.

[0059] In the present invention, the cations in the solid electrolyte preferably include Li ions and / or K ions.

[0060] In the present invention, the anions in the solid electrolyte include one or more of Cl ions, Br ions, S ions, and Se ions.

[0061] The present invention further provides a solid electrolyte, which is a molecular sieve type solid electrolyte. The anions in the solid electrolyte include one or more of Cl ions, Br ions, S ions, and Se ions.

[0062] In the present invention, the ionic conductivity of the solid electrolyte is 1*10 -7 ~5*10 -3 S cm -1 For example, 9.95*10 -6 S cm -1 , 1.2*10 -5 S cm -1 , 2.15*10 -5 S cm -1 , 2.27*10 -5 S cm -1 , 3.33*10 -5 S cm -1 , 4.29*10 -5 S cm -1 or 4.77*10 -5 S cm -1 is.

[0063] The present invention further provides the use of the above solid electrolyte in the manufacture of a battery.

[0064] In the present invention, different types of cations in the solid electrolyte correspond to different types of batteries, for example, when the cations in the solid electrolyte are lithium ions or lithium ions and potassium ions, it can be a lithium battery.

[0065] The present invention further provides an electrochemical device comprising the above-described solid electrolyte.

[0066] In the present invention, the electrochemical device is a battery, for example a lithium ion battery.

[0067] Each preferred embodiment of the present invention can be obtained by arbitrarily combining the above preferred conditions, provided that common knowledge in the relevant field is satisfied.

[0068] All of the reagents and raw materials used in the present invention can be obtained from commercial sources. [Effects of the Invention]

[0069] The positive advances and advantages of the present invention are as follows:

[0070] The solid electrolyte prepared in the present invention has high ionic conductivity and can be used alone as a solid electrolyte. [Brief explanation of the drawings]

[0071] [Figure 1] FIG. 1 is an SEM image of the solid electrolyte prepared in Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0072] The present invention will be further described in the form of examples below, but the scope of the present invention is not limited to the examples described. In addition, in the following examples, for experimental methods for which specific conditions are not specified, general methods and conditions may be used or selected according to the product instructions. [Example]

[0073] The NaY-type molecular sieve used in the examples and comparative examples described below was purchased from Nanka NKC Co., Ltd. The model number was NKY-7. Example 1

[0074] At room temperature, 1 g of NaY-type molecular sieve (12.5% ​​NaO mass fraction) was added to 50 mL of 2 M HAc aqueous solution (pH 2) and stirred at 400 rpm for 12 h. The stirred solution was then washed with deionized water three times by suction filtration and then dried in an oven at 60 °C for 3 h to obtain molecular sieve-H.

[0075] A halogenation reaction was carried out on molecular sieve-H. First, 700 μL of liquid bromine was dissolved in 100 mL of ethanol, and molecular sieve-H was added to the solution for a solvothermal reaction (performed in a reactor at 130 °C for 12 hours). After that, the solution was filtered with suction, washed with ethanol, and dried to obtain molecular sieve-X1.

[0076] The LiCl-KCl salt melted with a heat gun was mixed with molecular sieve-X1 (the ratio of the mass of LiCl to KCl was 1:1, and the ratio of the sum of the masses of LiCl and KCl to the mass of Na2O in the NaY-type molecular sieve was 8:1), and then calcined in a muffle furnace. The calcination temperature was 380°C, and the calcination time was 10 hours. The heating rate to the calcination temperature was 3°C / min. The calcined product was then washed three times with an appropriate amount of deionized water and dried at 60°C for 3 hours to obtain solid electrolyte AX2@molecular sieve-X1. Example 2

[0077] At room temperature, 1 g of NaY-type molecular sieve (12.5% ​​NaO mass fraction) was added to 50 mL of 2 M HAc aqueous solution (pH 2) and stirred at 400 rpm for 12 h. The stirred solution was then washed with deionized water three times by suction filtration and then dried in an oven at 60 °C for 3 h to obtain molecular sieve-H.

[0078] A halogenation reaction was carried out on molecular sieve-H. First, 700 μL of liquid bromine was dissolved in 100 mL of ethanol, and molecular sieve-H was added to the solution for a solvothermal reaction (performed in a reactor at 130 °C for 12 hours). After that, the solution was filtered with suction, washed with ethanol, and dried to obtain molecular sieve-X1.

[0079] The LiCl-LiNO3 salt melted with a heat gun was mixed with molecular sieve-X1 (the ratio of the mass of LiCl to LiNO3 was 1:1, and the ratio of the sum of the masses of LiCl and LiNO3 to the mass of Na2O in the NaY-type molecular sieve was 8:1), and then calcined in a muffle furnace. The calcination temperature was 380°C, and the calcination time was 10 hours. The heating rate to the calcination temperature was 3°C / min. The calcined product was then washed three times with an appropriate amount of deionized water and dried at 60°C for 3 hours to obtain solid electrolyte AX2@molecular sieve-X1. Example 3

[0080] At room temperature, 1 g of NaY-type molecular sieve (12.5% ​​NaO mass fraction) was added to 50 mL of 2 M HAc aqueous solution (pH 2) and stirred at 400 rpm for 12 h. The stirred solution was then washed with deionized water three times by suction filtration and then dried in an oven at 60 °C for 3 h to obtain molecular sieve-H.

[0081] A halogenation reaction was carried out on molecular sieve-H. First, 700 μL of liquid bromine was dissolved in 100 mL of ethanol, and molecular sieve-H was added to the solution for a solvothermal reaction (performed in a reactor at 130 °C for 12 hours). After that, the solution was filtered with suction, washed with ethanol, and dried to obtain molecular sieve-X1.

[0082] The LiCl-KCl salt melted with a heat gun was mixed with molecular sieve-X1 (the ratio of the mass of LiCl to KCl was 1:0.5, and the ratio of the sum of the masses of LiCl and KCl to the mass of Na2O in the NaY-type molecular sieve was 8:1), and then calcined in a muffle furnace. The calcination temperature was 380°C, and the calcination time was 10 hours. The heating rate to the calcination temperature was 3°C / min. The calcined product was then washed three times with an appropriate amount of deionized water and dried at 60°C for 3 hours to obtain solid electrolyte AX2@molecular sieve-X1. Example 4

[0083] At room temperature, 1 g of NaY-type molecular sieve (12.5% ​​NaO mass fraction) was added to 50 mL of 2 M HAc aqueous solution (pH 2) and stirred at 400 rpm for 12 h. The stirred solution was then washed with deionized water three times by suction filtration and then dried in an oven at 60 °C for 3 h to obtain molecular sieve-H.

[0084] A halogenation reaction was carried out on molecular sieve-H. First, 700 μL of liquid bromine was dissolved in 100 mL of ethanol, and molecular sieve-H was added to the solution for a solvothermal reaction (performed in a reactor at 130 °C for 12 hours). After that, the solution was filtered with suction, washed with ethanol, and dried to obtain molecular sieve-X1.

[0085] The LiCl-KCl salt melted with a heat gun was mixed with molecular sieve-X1 (the ratio of the mass of LiCl to KCl was 1:1.5, and the ratio of the sum of the masses of LiCl and KCl to the mass of Na2O in the NaY-type molecular sieve was 8:1), and then calcined in a muffle furnace. The calcination temperature was 380°C, and the calcination time was 10 hours. The heating rate to the calcination temperature was 3°C / min. The calcined product was then washed three times with an appropriate amount of deionized water and dried at 60°C for 3 hours to obtain solid electrolyte AX2@molecular sieve-X1. Example 5

[0086] At room temperature, 1 g of NaY-type molecular sieve (12.5% ​​NaO mass fraction) was added to 50 mL of 2 M HAc aqueous solution (pH 2) and stirred at 400 rpm for 12 h. The stirred solution was then washed with deionized water three times by suction filtration and then dried in an oven at 60 °C for 3 h to obtain molecular sieve-H.

[0087] A halogenation reaction was carried out on molecular sieve-H. First, 700 μL of liquid bromine was dissolved in 100 mL of ethanol, and molecular sieve-H was added to the solution for a solvothermal reaction (performed in a reactor at 130 °C for 12 hours). After that, the solution was filtered with suction, washed with ethanol, and dried to obtain molecular sieve-X1.

[0088] The LiBr-KBr salt melted with a heat gun was mixed with molecular sieve-X1 (the ratio of the mass of LiBr to KBr was 1:1, and the ratio of the sum of the masses of LiBr and KBr to the mass of Na2O in the NaY-type molecular sieve was 8:1), and then calcined in a muffle furnace. The calcination temperature was 380°C, and the calcination time was 10 hours. The heating rate to the calcination temperature was 3°C / min. The calcined product was then washed three times with an appropriate amount of deionized water and dried at 60°C for 3 hours to obtain solid electrolyte AX2@molecular sieve-X1. Example 6

[0089] At room temperature, 1 g of NaY-type molecular sieve (12.5% ​​NaO mass fraction) was added to 50 mL of 2 M HAc aqueous solution (pH 2) and stirred at 400 rpm for 12 h. The stirred solution was then washed with deionized water three times by suction filtration and then dried in an oven at 60 °C for 3 h to obtain molecular sieve-H.

[0090] A halogenation reaction was carried out on molecular sieve-H. First, 700 μL of liquid bromine was dissolved in 100 mL of ethanol, and molecular sieve-H was added to the solution for a solvothermal reaction (performed in a reactor at 130 °C for 12 hours). After that, the solution was filtered with suction, washed with ethanol, and dried to obtain molecular sieve-X1.

[0091] The LiCl-KCl salt melted with a heat gun was mixed with molecular sieve-X1 (the ratio of the mass of LiCl to KCl was 1:1; the ratio of the sum of the masses of LiCl and KCl to the mass of Na2O in the NaY-type molecular sieve was 4:1), and then calcined in a muffle furnace. The calcination temperature was 380°C, and the calcination time was 10 hours. The heating rate to the calcination temperature was 3°C / min. The calcined product was then washed three times with an appropriate amount of deionized water and dried at 60°C for 3 hours to obtain solid electrolyte AX2@molecular sieve-X1. Example 7

[0092] At room temperature, 1 g of NaY-type molecular sieve (12.5% ​​NaO mass fraction) was added to 50 mL of 2 M HAc aqueous solution (pH 2) and stirred at 400 rpm for 12 h. The stirred solution was then washed with deionized water three times by suction filtration and then dried in an oven at 60 °C for 3 h to obtain molecular sieve-H.

[0093] A halogenation reaction was carried out on molecular sieve-H. First, 700 μL of liquid bromine was dissolved in 100 mL of ethanol, and molecular sieve-H was added to the solution for a solvothermal reaction (performed in a reactor at 130 °C for 12 hours). After that, the solution was filtered with suction, washed with ethanol, and dried to obtain molecular sieve-X1.

[0094] The LiCl-KCl salt melted with a heat gun was mixed with molecular sieve-X1 (the ratio of the mass of LiCl to KCl was 1:1; the ratio of the sum of the masses of LiCl and KCl to the mass of Na2O in the NaY-type molecular sieve was 10:1), and then calcined in a muffle furnace. The calcination temperature was 380°C, and the calcination time was 10 hours. The heating rate to the calcination temperature was 3°C / min. The calcined product was then washed three times with an appropriate amount of deionized water and dried at 60°C for 3 hours to obtain solid electrolyte AX2@molecular sieve-X1. Comparative Example 1

[0095] Compared with Example 1, the 2M HAc aqueous solution was replaced with a 1M HCl aqueous solution (pH 0), and the remaining operations and conditions were all the same as in Example 1. Comparative Example 2

[0096] Compared with Example 1, the 2M HAc aqueous solution was replaced with a 0.1M HCl aqueous solution (pH 1), and the remaining operations and conditions were all the same as in Example 1. Comparative Example 3

[0097] Compared with Example 1, the 2M HAc aqueous solution was replaced with a 1M HAc aqueous solution (pH 2.2), and the remaining operations and conditions were all the same as in Example 1. Comparative Example 4

[0098] Compared with Example 1, the 2M HAc aqueous solution was replaced with a 0.1M HAc aqueous solution (pH 2.8), and the remaining operations and conditions were all the same as in Example 1. Example of effect

[0099] 1. Morphological Characterization FIG. 1 is an SEM image of the solid electrolyte prepared in Example 1.

[0100] 2. Ionic Conductivity Test At room temperature (25°C), 300 mg of the solid electrolytes prepared in Examples 1 to 7 and Comparative Examples 1 to 4 were placed in a mold and pressed at 300 MPa to produce a sheet with a radius of 5 mm and a thickness of 3 mm. Both ends of the mold were then connected to an Autolab, and an electrochemical impedance test was performed. The test results are shown in Table 1. [Table 1]

[0101] Although specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative and explanatory, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, and all such changes and modifications are within the scope of protection of the present invention.

Claims

1. A method for preparing a solid electrolyte, comprising: performing ion exchange of the molecular sieve-Na in an acidic solution, thereby exchanging cations in the pore channels of the molecular sieve-Na for protons; After washing and drying, the water molecules are evaporated to form molecular sieve-H, and oxygen and protons in the aluminum-oxygen tetrahedra of the molecular sieve-H combine to form OH; a halogenation reaction to exchange OH in the molecular sieve-H with halogen X1 (X1=F, Cl, Br, I) to obtain molecular sieve-X1; and calcining the molecular sieve-X1 and the molten AX2 to allow the cations and anions in the AX2 to enter the pores of the molecular sieve-X1, thereby obtaining the solid electrolyte AX2@molecular sieve-X1. The method is characterized in that the pH of the acidic solution is 1.2<pH<2.1, the AX2 contains an alkali metal halide and / or an alkali metal chalcogenide, and the firing temperature is 300 to 500°C.

2. The pore size of the molecular sieve-Na is 0.5 to 100 nm; and / or the type of the molecular sieve-Na is one or more of X-type, A-type, Y-type and ZSM-5-type, for example, X-type; The method for preparing a solid electrolyte according to claim 1, wherein the type of said molecular sieve-Na is preferably NaY type molecular sieve.

3. the pH of the acidic solution is 1.8<pH<2.1, for example 2.0; and / or the acidic solution comprises one or more of acetic acid, hydrochloric acid, benzoic acid, formic acid and salicylic acid, such as acetic acid; and / or the concentration of the acidic solution is 1.5 to 4 mol / L, for example, 2 mol / L or 3 mol / L.

4. the ratio of the mass of the molecular sieve-Na to the volume of the acidic solution is 1:(40-80) g / mL, for example, 1:50 g / mL; and / or the ion exchange time is 8 to 20 hours, for example 12 hours; and / or the temperature during the drying is 40 to 80°C, for example 60°C; And / or, the drying time is 2 to 8 hours, for example, 3 hours.

5. the cation of AX2 includes Li ions and / or K ions; and / or the anion of AX2 comprises one or more of Cl ions, Br ions, S ions and Se ions; and / or AX2 is a mixed salt of lithium chloride and potassium chloride, a mixed salt of lithium bromide and potassium bromide, or a mixed salt of lithium chloride and lithium nitrate, preferably a mixed salt of lithium chloride and potassium chloride; When AX2 is a mixed salt of lithium chloride and potassium chloride, the ratio of the amount of the lithium chloride to the amount of the potassium chloride is preferably 1:(0.5 to 1.5), more preferably 1:(0.8 to 1.2), for example, 1:0.5, 1:1, or 1:1.5; When AX2 is a mixed salt of lithium bromide and potassium bromide, the ratio of the amount of lithium bromide to the amount of potassium bromide is preferably 1: (0.5 to 1.5), for example, 1:1; When AX2 is a mixed salt of lithium chloride and lithium nitrate, the ratio of the amount of lithium chloride to the amount of lithium nitrate is preferably 1:(0.5 to 1.5), for example, 1:1; And / or the amount of substance of AX2 and Na in the molecular sieve ２ The method for preparing a solid electrolyte according to claim 1 or 2, wherein the ratio of the amount of substance of O to the amount of substance of SiO is preferably (3 to 15):1, for example, 4:1, 8:1, 9:1, 10:1, or 12:

1.

6. The substance containing the halogen X1 used in the halogenation reaction is a halogen element or an ammonium salt, Preferably, the halogen element is liquid bromine, chlorine gas, or iodine; And / or, the halogenation reaction method is, when the substance containing the halogen X1 is a halogen gas alone, to carry out chemical vapor deposition of the molecular sieve-H and the halogen gas alone, and when the substance containing the halogen X1 is a halogen liquid alone, a halogen solid alone, or an ammonium salt, to carry out a solvothermal reaction of the molecular sieve-H and the substance containing the halogen X1; Preferably, the temperature of the solvothermal reaction is 110-150°C, for example 130°C; Preferably, the duration of the solvothermal reaction is between 8 and 16 hours, for example 12 hours; and / or the firing temperature is 350 to 500°C, for example, 380°C, 400°C, or 450°C; And / or, the baking time is 8 to 20 hours, for example, 10 hours or 15 hours.

7. A solid electrolyte prepared by the method for preparing a solid electrolyte according to any one of claims 1 to 6, A solid electrolyte, wherein cations in the solid electrolyte preferably include Li ions and / or K ions, and anions in the solid electrolyte preferably include one or more of Cl ions, Br ions, S ions, and Se ions.

8. A molecular sieve-type solid electrolyte, wherein anions in the solid electrolyte include one or more of Cl ions, Br ions, S ions, and Se ions.

9. 9. Use of the solid electrolyte according to claim 7 or 8 in the manufacture of a battery.

10. 1. An electrochemical device comprising: The solid electrolyte according to claim 7 or 8 is included, The electrochemical device is preferably a battery, for example a lithium ion battery.

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