Solid-state electrolyte, preparation method therefor and use thereof, and electrochemical device

Abstract

The present invention provides a solid-state electrolyte, a preparation method therefor and a use thereof, and an electrochemical device. The preparation method comprises: performing ion exchange on a molecular sieve -Na in an acidic solution, so that cations in pores of the molecular sieve -Na are exchanged into protons; after washing and drying, evaporating water molecules to form a molecular sieve -H, and combining oxygen in an aluminum-oxygen tetrahedron of the molecular sieve -H with the protons to form OH; exchanging OH in the molecular sieve -H into halogen X1 (X1=F, Cl, Br, or I) by means of a halogenation reaction, so as to obtain a molecular sieve -X1; and calcining the molecular sieve -X1 and molten AX2 to obtain the solid-state electrolyte, the pH of the acidic solution being greater than 1.2 and less than 2.1, AX2 comprising an alkali metal halide and / or an alkali metal chalcogenide, and the calcination temperature ranging from 300°C to 500°C. The solid-state electrolyte has high ionic conductivity, and can be independently used as a solid-state electrolyte.

Description

A solid electrolyte and its preparation method, application and electrochemical device Technical Field

[0001] The invention relates to a solid electrolyte and a preparation method, application and electrochemical device thereof. Background Art

[0002] In recent years, new energy vehicles, represented by electric vehicles, have rapidly captured the automotive market. As a core component in electric vehicles, the performance of power batteries has a significant impact on their actual performance. Currently, the chemical system used in commercial power batteries is lithium-ion batteries. Compared to traditional lithium-ion batteries that use electrolytes, all-solid-state lithium batteries use solid electrolytes instead of electrolytes and separators, making them thinner and smaller in size. This increases the battery's energy density and improves battery safety.

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

[0004] For example, Chinese patent document CN116666737A discloses a composite solid electrolyte, a lithium battery, and a preparation method. The modified molecular sieve is obtained by placing a molecular sieve in a lithium salt solution for ion exchange; a polymer, a lithium salt, the modified molecular sieve, and a solvent are then mixed to obtain a composite polymer electrolyte; and the composite polymer electrolyte is coated on a porous base membrane to obtain a composite solid electrolyte, thereby solving the problems of poor mechanical strength and low lithium ion conductivity of existing lithium batteries.

[0005] Chinese patent document CN111755734A discloses a molecular sieve-loaded sodium ion solid electrolyte, its preparation method and application. The solid electrolyte is prepared by using molecular sieve, ionic liquid and sodium salt as raw materials, thereby improving the ionic conductivity of the solid electrolyte.

[0006] The above two patent documents prepare solid electrolytes by combining molecular sieves with polymer electrolytes or ionic liquids. This composite solid electrolyte is unstable in the air and easily absorbs water, which is not conducive to transportation and storage.

[0007] Therefore, developing a molecular sieve-type solid electrolyte that not only has high ionic conductivity but can also be used alone is a problem to be solved by those skilled in the art. Summary of the Invention

[0008] The technical problem addressed by the present invention is to overcome the existing drawbacks of molecular sieves, which have low ionic conductivity and cannot be used alone as solid electrolytes. The present invention provides a solid electrolyte, its preparation method, application, and electrochemical device. The solid electrolyte prepared by the present invention has high ionic conductivity and can be used alone as a solid electrolyte.

[0009] Molecular sieves often suffer from low ionic conductivity when used as solid electrolytes. Existing technologies typically enhance ionic conductivity by combining molecular sieves with polymer electrolytes or ionic liquids or by introducing cations into the molecular sieve. However, the oxygen anions in the molecular sieves readily bind to the metal cations within them, hindering their migration and resulting in low ionic conductivity. The present invention exchanges the metal cations of the molecular sieve for protons first. After drying, the water molecules in the molecular sieve evaporate, so that the oxygen in the aluminum oxide tetrahedron of the molecular sieve combines with the protons to form OH; the OH in the molecular sieve is exchanged for halogen through a halogenation reaction, thereby reducing the concentration of oxygen anions in the molecular sieve and facilitating the migration of metal cations; in addition, in order to further improve the migration speed of metal cations, the molecular sieve obtained after the halogenation reaction is calcined with a molten alkali metal salt, so that the cations and anions in the alkali metal salt are introduced into the molecular sieve. The anions in the alkali metal salt will be arranged at the edge of the molecular sieve pores, so that the alkali metal cations can better shuttle freely in the pores, further improving the migration rate of the alkali metal cations in the pores, thereby improving the ionic conductivity of the solid electrolyte.

[0010] The present invention solves the above technical problems through the following technical solutions:

[0011] The present invention provides a method for preparing a solid electrolyte, which comprises the following steps: subjecting molecular sieve-Na to ion exchange in an acidic solution, so that cations in the pores of the molecular sieve-Na are exchanged for protons; after washing and drying, water molecules are evaporated to form molecular sieve-H, and oxygen in the aluminum oxide tetrahedron of the molecular sieve-H combines with the protons to form OH; exchanging OH in the molecular sieve-H with halogen X1 (X1=F, Cl, Br, I) through a halogenation reaction to obtain molecular sieve-X1; and calcining the molecular sieve-X1 and melted AX2 to allow cations and anions in AX2 to enter the pores of the molecular sieve-X1, thereby obtaining the solid electrolyte AX2@molecular sieve-X1.

[0012] The pH of the acidic solution is 1.2<pH<2.1; the AX2 includes an alkali metal halide and / or an alkali metal sulfide; and the calcination temperature is 300-500°C.

[0013] In the present invention, the preparation method preferably includes the following steps: subjecting molecular sieve-Na to ion exchange in an acidic solution, washing, and drying to form molecular sieve-H; subjecting the molecular sieve-H to a halogenation reaction to obtain molecular sieve-X1; and calcining the molecular sieve-X1 and melted AX2 to obtain the solid electrolyte AX2@molecular sieve-X1.

[0014] The pH of the acidic solution is 1.2<pH<2.1; the AX2 includes an alkali metal halide and / or an alkali metal sulfide; and the calcination temperature is 300-500°C.

[0015] In the present invention, during the ion exchange process in the acidic solution, the pH of the acidic solution has an important influence on the structure of the molecular sieve and the degree to which cations in the molecular sieve pores are exchanged for protons. When the pH of the acid used is 1.2 < pH < 2.2, the higher the degree to which cations in the molecular sieve pores are exchanged for protons, the more conducive it is to the subsequent entry of alkali metal salts.

[0016] In the present invention, during the halogenation reaction, compared with divalent oxygen, monovalent halogen ions generally have a lower ionic potential (Φ=Z / r), and their binding force with alkali metal ions is weaker, which facilitates the rapid transport of alkali metal ions between pores.

[0017] In the present invention, the pore size of the molecular sieve-Na can be 0.5-100 nm.

[0018] 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.

[0019] In the present invention, the molecular sieve-Na refers to a molecular sieve whose cation is Na ion.

[0020] In a specific embodiment, the type of the molecular sieve-Na is NaY type molecular sieve.

[0021] In the present invention, the mass fraction of Na2O in the molecular sieve-Na may be 8%-15%, for example, 12.5%. The mass fraction refers to the percentage of the mass of Na2O to the mass of the molecular sieve.

[0022] In the present invention, the silicon-aluminum ratio in the molecular sieve-Na can be 0.9 to 5. The silicon-aluminum ratio refers to the molar ratio of SiO2 / Al2O3.

[0023] In the present invention, the pH of the acidic solution is preferably 1.8<pH<2.1, for example 2.0.

[0024] In the present invention, the acidic solution may include one or more of acetic acid, hydrochloric acid, benzoic acid, formic acid and salicylic acid, such as acetic acid.

[0025] In the present invention, the concentration of the acidic solution may be 1.5-4 mol / L, for example 2 mol / L or 3 mol / L.

[0026] In a specific embodiment, the acidic solution is 2 mol / L acetic acid.

[0027] 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.

[0028] In the present invention, the ion exchange is generally carried out at room temperature.

[0029] In the present invention, the ion exchange time may be 8-20 hours, for example 12 hours.

[0030] In the present invention, the ion exchange is preferably carried out under stirring. The stirring speed may be 200-800 rpm, for example 400 rpm.

[0031] In the present invention, the washing is generally performed with deionized water. The washing method may be suction filtration. The number of washing times is generally three or more.

[0032] In the present invention, the drying temperature may be 40-80° C., for example, 60° C. The drying time may be 2-8 hours, for example, 3 hours. The drying is generally performed in an oven.

[0033] In the present invention, the substance containing the halogen X1 used in the halogenation reaction can be a halogen element or an ammonium salt. The halogen element can be, for example, liquid bromine, chlorine gas, or iodine element. When the halogen X1 is F, the ammonium salt can be ammonium fluoride or ammonium bifluoride.

[0034] In the present invention, the mode of the halogenation reaction can be flexibly selected according to the form of the substance containing the halogen X1. For example, when the substance containing the halogen X1 is a halogen gas element, the molecular sieve-H and the halogen gas element can be subjected to chemical vapor deposition; when the substance containing the halogen X1 is a halogen liquid element, a halogen solid element or an ammonium salt, the molecular sieve-H and the substance containing the halogen X1 can be subjected to a solvent thermal reaction.

[0035] The solvothermal reaction is generally carried out in a reactor. During the solvothermal process, the solvent selected may be deionized water and / or an alcoholic solvent. The alcoholic solvent may be ethanol. The solvothermal reaction temperature may be 110-150°C, for example, 130°C. The solvothermal reaction time may be 8-16 hours, for example, 12 hours.

[0036] In one embodiment, the halogenation reaction comprises the following steps: reacting a mixture containing the molecular sieve-H, liquid bromine, and ethanol in a reactor at a temperature of 130° C. for 12 hours. The ratio of the mass of the molecular sieve-Na to the volume of the liquid bromine can be (1.2-1.6) mg / μL, for example, 1.43 mg / μL. The volume ratio of the liquid bromine to the ethanol can be 0.001-0.2, for example, 0.007.

[0037] In the present invention, the cations of AX2 preferably include Li ions and / or K ions.

[0038] In the present invention, the anion of AX2 includes one or more of Cl ions, Br ions, S ions and Se ions.

[0039] In the present invention, the alkali metal halide may be an alkali metal chloride or an alkali metal bromide.

[0040] In the present invention, the alkali metal sulfide may be an alkali metal sulfide or an alkali metal selenide.

[0041] In the present invention, AX2 can 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, preferably a mixed salt of lithium chloride and potassium chloride.

[0042] In a specific embodiment, the AX2 is a mixed salt of lithium chloride and potassium chloride.

[0043] When AX2 is a mixed salt of lithium chloride and potassium chloride, the molar ratio of the lithium chloride to the potassium chloride may be 1:(0.5-1.5), preferably 1:(0.8-1.2), for example 1:0.5, 1:1 or 1:1.5.

[0044] In a specific embodiment, the AX2 is a mixed salt of lithium bromide and potassium bromide.

[0045] When AX2 is a mixed salt of lithium bromide and potassium bromide, the molar ratio of the lithium bromide to the potassium bromide may be 1:(0.5-1.5), for example, 1:1.

[0046] In a specific embodiment, the AX2 is a mixed salt of lithium chloride and lithium nitrate.

[0047] When AX2 is a mixed salt of lithium chloride and lithium nitrate, the molar ratio of the lithium chloride to the lithium nitrate may be 1:(0.5-1.5), for example, 1:1.

[0048] In the present invention, the ratio of the amount of AX2 to the amount of Na2O in the molecular sieve is preferably (5-15):1, such as 4:1, 8:1, 9:1, 10:1 or 12:1.

[0049] In the present invention, the method for preparing the melted AX2 may include the following steps: melting the AX2 using a high-temperature gun, or heating and melting the AX2 in a muffle furnace or a tube furnace.

[0050] In the present invention, the calcination is generally carried out in an air atmosphere and the calcination equipment is generally a muffle furnace.

[0051] In the present invention, the calcination temperature may be 350-500°C, such as 380°C, 400°C or 450°C.

[0052] In the present invention, the calcination time may be 8-20 hours, such as 10 hours or 15 hours.

[0053] In the present invention, the rate of heating to the calcination temperature may be 0.5-10°C / min, preferably 1-5°C / min, for example 3°C / min.

[0054] In the present invention, washing and drying are preferably performed after calcination.

[0055] The washing is generally performed with deionized water and is generally performed three or more times.

[0056] The drying temperature may be 40-80° C., for example, 60° C. The drying time may be 2-8 hours, for example, 3 hours. The drying is generally performed in an oven.

[0057] The present invention also provides a solid electrolyte prepared by the above-mentioned method for preparing the solid electrolyte.

[0058] In the present invention, the cations in the solid electrolyte preferably include Li ions and / or K ions.

[0059] In the present invention, the anions in the solid electrolyte include one or more of Cl ions, Br ions, S ions and Se ions.

[0060] The present invention also provides a solid electrolyte, which is a molecular sieve type solid electrolyte, wherein the anions in the solid electrolyte include one or more of Cl ions, Br ions, S ions and Se ions.

[0061] In the present invention, the ionic conductivity of the solid electrolyte can be 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 、.

[0062] The present invention also provides a use of the above-mentioned solid electrolyte in preparing a battery.

[0063] 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 used as a lithium battery.

[0064] The present invention also provides an electrochemical device, which includes the solid electrolyte as described above.

[0065] In the present invention, the electrochemical device is a battery, such as a lithium-ion battery.

[0066] On the basis of conforming to the common sense in this field, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0067] The reagents and raw materials used in the present invention are commercially available.

[0068] The positive progress effect of the present invention is:

[0069] The solid electrolyte prepared by the present invention has high ionic conductivity and can be used alone as a solid electrolyte. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] FIG1 is a SEM image of the solid electrolyte prepared in Example 1. DETAILED DESCRIPTION

[0071] The present invention is further illustrated by way of examples below, but the present invention is not limited to the scope of the examples. Experimental methods in the following examples where specific conditions are not specified were performed according to conventional methods and conditions, or selected according to the product specifications.

[0072] The NaY molecular sieve used in the following examples and comparative examples was purchased from Nanhua NKC, model NKY-7.

[0073] Example 1

[0074] At room temperature, 1 g of NaY molecular sieve (Na2O mass fraction of 12.5%) was added to 50 mL of 2MHAc aqueous solution (pH 2) and stirred at 400 rpm for 12 h. The stirred solution was filtered and washed three times with deionized water, and then dried in an oven at 60°C for 3 h to obtain molecular sieve-H.

[0075] Halogenation of molecular sieve-H: Dissolve 700 μL of liquid bromine in 100 mL of ethanol, add molecular sieve-H, and perform a solvothermal reaction (carried out in a reactor at 130°C for 12 h), followed by filtration, ethanol washing, and drying to obtain molecular sieve-X1;

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

[0077] Example 2

[0078] At room temperature, 1 g of NaY molecular sieve (Na2O mass fraction of 12.5%) was added to 50 mL of 2MHAc aqueous solution (pH 2) and stirred at 400 rpm for 12 h. The stirred solution was filtered and washed three times with deionized water, and then dried in an oven at 60°C for 3 h to obtain molecular sieve-H.

[0079] Halogenation of molecular sieve-H: Dissolve 700 μL of liquid bromine in 100 mL of ethanol, add molecular sieve-H, and perform a solvothermal reaction (carried out in a reactor at 130°C for 12 h), followed by filtration, ethanol washing, and drying to obtain molecular sieve-X1;

[0080] The LiCl-LiNO3 salt melted by a high-temperature gun and the molecular sieve-X1 were mixed (the molar ratio of LiCl and LiNO3 was 1:1, and the molar ratio of the sum of the moles of LiCl and LiNO3 to the molar ratio of Na2O in the NaY type molecular sieve was 8:1), and calcined in a muffle furnace at a temperature of 380°C for 10 hours. The temperature was raised to the calcination temperature at a rate of 3°C / min. The calcined product was washed three times with an appropriate amount of deionized water and dried at 60°C for 3 hours to obtain the solid electrolyte AX2@molecular sieve-X1.

[0081] Example 3

[0082] At room temperature, 1 g of NaY molecular sieve (Na2O mass fraction of 12.5%) was added to 50 mL of 2MHAc aqueous solution (pH 2) and stirred at 400 rpm for 12 h. The stirred solution was filtered and washed three times with deionized water, and then dried in an oven at 60°C for 3 h to obtain molecular sieve-H.

[0083] Halogenation of molecular sieve-H: Dissolve 700 μL of liquid bromine in 100 mL of ethanol, add molecular sieve-H, and perform a solvothermal reaction (carried out in a reactor at 130°C for 12 h), followed by filtration, ethanol washing, and drying to obtain molecular sieve-X1;

[0084] The LiCl-KCl salt melted by a high-temperature gun and the molecular sieve-X1 were mixed (the molar ratio of LiCl and KCl was 1:0.5, and the molar ratio of the sum of the moles of LiCl and KCl to the molar ratio of Na2O in the NaY type molecular sieve was 8:1), and calcined in a muffle furnace at a temperature of 380°C for 10 hours. The temperature was raised to the calcination temperature at a rate of 3°C / min. The calcined product was washed three times with an appropriate amount of deionized water and then dried at 60°C for 3 hours to obtain the solid electrolyte AX2@molecular sieve-X1.

[0085] Example 4

[0086] At room temperature, 1 g of NaY molecular sieve (Na2O mass fraction of 12.5%) was added to 50 mL of 2MHAc aqueous solution (pH 2) and stirred at 400 rpm for 12 h. The stirred solution was filtered and washed three times with deionized water, and then dried in an oven at 60°C for 3 h to obtain molecular sieve-H.

[0087] Halogenation of molecular sieve-H: Dissolve 700 μL of liquid bromine in 100 mL of ethanol, add molecular sieve-H, and perform a solvothermal reaction (carried out in a reactor at 130°C for 12 h), followed by filtration, ethanol washing, and drying to obtain molecular sieve-X1;

[0088] The LiCl-KCl salt melted by a high-temperature gun and the molecular sieve-X1 were mixed (the molar ratio of LiCl and KCl was 1:1.5, and the molar ratio of the sum of the moles of LiCl and KCl to the molar ratio of Na2O in the NaY type molecular sieve was 8:1), and calcined in a muffle furnace at a temperature of 380°C for 10 hours. The temperature was raised to the calcination temperature at a rate of 3°C / min. The calcined product was washed three times with an appropriate amount of deionized water and then dried at 60°C for 3 hours to obtain the solid electrolyte AX2@molecular sieve-X1.

[0089] Example 5

[0090] At room temperature, 1 g of NaY molecular sieve (Na2O mass fraction of 12.5%) was added to 50 mL of 2MHAc aqueous solution (pH 2) and stirred at 400 rpm for 12 h. The stirred solution was filtered and washed three times with deionized water, and then dried in an oven at 60°C for 3 h to obtain molecular sieve-H.

[0091] Halogenation of molecular sieve-H: Dissolve 700 μL of liquid bromine in 100 mL of ethanol, add molecular sieve-H, and perform a solvothermal reaction (carried out in a reactor at 130°C for 12 h), followed by filtration, ethanol washing, and drying to obtain molecular sieve-X1;

[0092] The LiBr-KBr salt melted by a high-temperature gun and the molecular sieve-X1 were mixed (the molar ratio of LiBr and KBr was 1:1, and the molar ratio of the sum of the moles of LiBr and KBr to the molar ratio of Na2O in the NaY type molecular sieve was 8:1), and calcined in a muffle furnace at a temperature of 380°C for 10 hours. The temperature was raised to the calcination temperature at a rate of 3°C / min. The calcined product was washed three times with an appropriate amount of deionized water and dried at 60°C for 3 hours to obtain the solid electrolyte AX2@molecular sieve-X1.

[0093] Example 6

[0094] At room temperature, 1 g of NaY molecular sieve (Na2O mass fraction of 12.5%) was added to 50 mL of 2MHAc aqueous solution (pH 2) and stirred at 400 rpm for 12 h. The stirred solution was filtered and washed three times with deionized water, and then dried in an oven at 60°C for 3 h to obtain molecular sieve-H.

[0095] Halogenation of molecular sieve-H: Dissolve 700 μL of liquid bromine in 100 mL of ethanol, add molecular sieve-H, and perform a solvothermal reaction (carried out in a reactor at 130°C for 12 h), followed by filtration, ethanol washing, and drying to obtain molecular sieve-X1;

[0096] The LiCl-KCl salt melted by a high-temperature gun and the molecular sieve-X1 were mixed (the molar ratio of LiCl and KCl was 1:1, and the molar ratio of the sum of the moles of LiCl and KCl to the molar ratio of Na2O in the NaY type molecular sieve was 4:1), and calcined in a muffle furnace at a temperature of 380°C for 10 hours. The temperature was raised to the calcination temperature at a rate of 3°C / min. The calcined product was washed three times with an appropriate amount of deionized water and then dried at 60°C for 3 hours to obtain the solid electrolyte AX2@molecular sieve-X1.

[0097] Example 7

[0098] At room temperature, 1 g of NaY molecular sieve (Na2O mass fraction of 12.5%) was added to 50 mL of 2MHAc aqueous solution (pH 2) and stirred at 400 rpm for 12 h. The stirred solution was filtered and washed three times with deionized water, and then dried in an oven at 60°C for 3 h to obtain molecular sieve-H.

[0099] Halogenation of molecular sieve-H: Dissolve 700 μL of liquid bromine in 100 mL of ethanol, add molecular sieve-H, and perform a solvothermal reaction (carried out in a reactor at 130°C for 12 h), followed by filtration, ethanol washing, and drying to obtain molecular sieve-X1;

[0100] The LiCl-KCl salt melted by a high-temperature gun and the molecular sieve-X1 were mixed (the molar ratio of LiCl and KCl was 1:1, and the molar ratio of the sum of the moles of LiCl and KCl to the molar ratio of Na2O in the NaY type molecular sieve was 10:1), and calcined in a muffle furnace at a temperature of 380°C for 10 hours. The temperature was raised to the calcination temperature at a rate of 3°C / min. The calcined product was washed three times with an appropriate amount of deionized water and then dried at 60°C for 3 hours to obtain the solid electrolyte AX2@molecular sieve-X1.

[0101] Comparative Example 1

[0102] Compared with Example 1, except that the 2M HAc aqueous solution was replaced by a 1M HCl aqueous solution (pH 0), the other operations and conditions were the same as those in Example 1.

[0103] Comparative Example 2

[0104] Compared with Example 1, except that the 2M HAc aqueous solution was replaced by a 0.1M HCl aqueous solution (pH 1), the other operations and conditions were the same as those in Example 1.

[0105] Comparative Example 3

[0106] Compared with Example 1, except that the 2M HAc aqueous solution was replaced by a 1M HAc aqueous solution (pH 2.2), the other operations and conditions were the same as those in Example 1.

[0107] Comparative Example 4

[0108] Compared with Example 1, except that the 2M HAc aqueous solution was replaced by a 0.1M HAc aqueous solution (pH 2.8), the other operations and conditions were the same as those in Example 1.

[0109] Effect embodiment

[0110] 1. Morphology characterization

[0111] FIG1 is a SEM image of the solid electrolyte prepared in Example 1.

[0112] 2. Ionic conductivity test

[0113] At room temperature (25°C), 300 mg of the solid electrolytes prepared in Examples 1-7 and Comparative Examples 1-4 were placed in a mold and formed into a sheet with a radius of 5 mm and a thickness of 3 mm at a pressure of 300 MPa. The two ends of the mold were connected to an Autolab for electrochemical impedance spectroscopy (EIS) testing. The test results are shown in Table 1.

[0114] Table 1

[0115] Although specific embodiments of the present invention have been described above, those skilled in the art will appreciate that these are merely illustrative and that the scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, and such changes and modifications are intended to fall within the scope of the present invention.

Claims

1. A method for preparing a solid electrolyte, characterized in that: The following steps are involved: The molecular sieve-Na is subjected to ion exchange in an acidic solution, so that the cations in the pores of the molecular sieve-Na are exchanged for protons; after washing and drying, the water molecules evaporate to form the molecular sieve-H, and the oxygen in the aluminum oxide tetrahedron of the molecular sieve-H combines with the protons to form OH; the OH in the molecular sieve-H is exchanged for halogen X1 (X1 = F, Cl, Br, I) through a halogenation reaction to obtain the molecular sieve-X1; the molecular sieve-X1 and the melted AX2 are then calcined so that the cations and anions in the AX2 can enter the pores of the molecular sieve-X1, thereby obtaining the solid electrolyte AX2@molecular sieve-X1; The pH of the acidic solution is 1.2<pH<2.1; the AX2 includes an alkali metal halide and / or an alkali metal sulfide; and the calcination temperature is 300-500°C.

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

3. The method for preparing a solid electrolyte according to claim 1 or 2, wherein: 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 1.5-4 mol / L, such as 2 mol / L or 3 mol / L.

4. The method for preparing a solid electrolyte according to claim 1 or 2, wherein: 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 8-20 hours, for example 12 hours; and / or, the drying temperature is 40-80° C., for example 60° C.; And / or, the drying time is 2-8 hours, for example 3 hours.

5. The method for preparing a solid electrolyte according to claim 1 or 2, wherein: The cations of AX2 include Li ions and / or K ions; and / or, the anion of AX2 includes 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 amount ratio of the lithium chloride to the potassium chloride is preferably 1:(0.5-1.5), more preferably 1:(0.8-1.2), for example 1:0.5, 1:1 or 1:1.5; When the AX2 is a mixed salt of lithium bromide and potassium bromide, the amount ratio of the lithium bromide to the potassium bromide is preferably 1:(0.5-1.5), for example 1:1; When AX2 is a mixed salt of lithium chloride and lithium nitrate, the amount ratio of the lithium chloride to the lithium nitrate is preferably 1:(0.5-1.5), for example 1:1; And / or, the ratio of the amount of AX2 to the amount of Na2O in the molecular sieve is preferably (3-15):1, such as 4:1, 8:1, 9:1, 10:1 or 12:

1.

6. The method for preparing a solid electrolyte according to claim 1 or 2, wherein: During the halogenation reaction, the substance containing the halogen X1 is a halogen element or an ammonium salt; Preferably, the halogen element is liquid bromine, chlorine gas or iodine element; And / or, the halogenation reaction is carried out in the following manner: when the substance containing the halogen X1 is a halogen gas element, the molecular sieve-H and the halogen gas element are subjected to chemical vapor deposition; when the substance containing the halogen X1 is a halogen liquid element, a halogen solid element or an ammonium salt, the molecular sieve-H and the substance containing the halogen X1 are subjected to a solvothermal reaction; Preferably, the temperature of the solvothermal reaction is 110-150°C, for example 130°C; Preferably, the solvent thermal reaction time is 8-16 hours, for example 12 hours; and / or, the calcination temperature is 350-500° C., for example, 380° C., 400° C. or 450° C.; And / or, the calcination time is 8-20 hours, such as 10 hours or 15 hours.

7. A solid electrolyte, characterized in that It is prepared according to the preparation method of the solid electrolyte according to any one of claims 1 to 6; The cations in the solid electrolyte preferably include Li ions and / or K ions; the anions in the solid electrolyte preferably include one or more of Cl ions, Br ions, S ions and Se ions.

8. A solid electrolyte, characterized in that It is a molecular sieve type solid electrolyte, and the anions in the solid electrolyte include one or more of Cl ions, Br ions, S ions and Se ions.

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

10. An electrochemical device, characterized in that It comprises the solid electrolyte according to claim 7 or 8; The electrochemical device is preferably a battery, such as a lithium-ion battery.

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