Solid electrolyte slurry and preparation method thereof, solid electrolyte, solid-state battery

Abstract

The present invention belongs to the technical field of solid-state batteries, and specifically discloses a solid electrolyte slurry and a preparation method thereof, a solid electrolyte, and a solid-state battery. The preparation method of the solid electrolyte slurry comprises the following steps: dissolving a nickel salt, a cobalt salt, a manganese salt and a surfactant in a solvent to obtain a solution A; dissolving a ligand in a solvent to obtain a solution B; adding solution A to solution B for reaction, and after the reaction is completed, obtaining a NiCoMn-MOF material; heating and heat-insulating the NiCoMn-MOF material in an oxygen-containing atmosphere to obtain a modified NiCoMn-MOF material; mixing the modified NiCoMn-MOF material, a lithium salt, a polymer and a solvent 1 to obtain a solid electrolyte slurry. The solid electrolyte slurry of the present invention adds a modified NiCoMn-MOF similar to a ternary material, which can suppress the dissolution of transition metals of the positive electrode material.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid-state batteries, and in particular relates to a solid-state electrolyte slurry and a preparation method thereof, a solid-state electrolyte, and a solid-state battery. Background Art

[0002] Among many chemical energy storage devices, lithium-ion batteries have attracted widespread attention due to their excellent energy storage performance. Traditional lithium batteries usually use flammable organic liquid electrolytes as the conductive medium for lithium ions, but liquid electrolytes have safety hazards such as leakage, combustion, and explosion. Solid electrolytes are almost non-flammable, and metallic lithium can be used as the negative electrode, which helps to improve the energy density. Therefore, the use of solid electrolytes instead of organic liquid electrolytes is expected to fundamentally solve the safety problem. However, solid electrolytes currently face some problems, such as poor contact with the positive and negative electrode interfaces, low ion conductivity, etc.; these problems restrict the development of solid electrolytes. In addition, after some positive electrode materials such as ternary positive electrode materials are assembled into solid-state batteries, transition metals dissolve during the cycle process, which can easily lead to the performance failure of solid-state batteries. Summary of the invention

[0003] The purpose of the present invention is to provide a solid electrolyte slurry and a preparation method thereof, a solid electrolyte, and a solid-state battery, which can effectively improve the ionic conductivity of the solid electrolyte, thereby further improving the electrochemical performance of the solid-state battery.

[0004] In a first aspect, the present invention provides a method for preparing a solid electrolyte slurry, which adopts the following technical scheme:

[0005] A method for preparing a solid electrolyte slurry comprises the following steps:

[0006] (1) dissolving nickel salt, cobalt salt, manganese salt and surfactant in a solvent to obtain solution A; dissolving a ligand in a solvent to obtain solution B; adding solution A to solution B for reaction, and after the reaction is completed, obtaining a NiCoMn-MOF material; heating and heat-insulating the NiCoMn-MOF material in an oxygen-containing atmosphere to obtain a modified NiCoMn-MOF material;

[0007] (2) The modified NiCoMn-MOF material prepared in step (1), lithium salt, polymer and solvent 1 are mixed to obtain a solid electrolyte slurry.

[0008] Preferably, in step (1), the nickel salt is one or more of nickel nitrate, nickel sulfate, and nickel chloride; the cobalt salt is one or more of cobalt nitrate, cobalt sulfate, and cobalt chloride; the manganese salt is one or more of manganese nitrate, manganese sulfate, and manganese chloride; and the nickel salt, cobalt salt, and manganese salt are added in a molar ratio of Ni, Co, and Mn of (55-65):(15-25):(15-25).

[0009] Preferably, in step (1), the surfactant is one or more of dodecyltrimethylammonium bromide, n-octyltrimethylammonium bromide, sodium dodecylbenzenesulfonate, and sodium dodecyl sulfate; the mass ratio of the total molar number of Ni, Co and Mn in the nickel salt, cobalt salt and manganese salt to the surfactant is (85-115) mmol: (0.008-0.013) g; and the solvent is one or more of methanol, ethanol and water.

[0010] Preferably, in step (1), the ligand is one or both of imidazole and 2-methylimidazole.

[0011] Preferably, in step (1), the ratio of the total molar number of Ni, Co and Mn in the nickel salt, cobalt salt and manganese salt to the molar number of the ligand is (85-115):(350-500).

[0012] Preferably, in step (1), the reaction time is 12 to 24 hours; the heating and insulation temperature is 180 to 250° C., and the heating and insulation time is 30 to 120 minutes.

[0013] Preferably, in step (2), the polymer is one or more of PVDF (polyvinylidene fluoride), PVDF-HFP (polyvinylidene fluoride-hexafluoropropylene copolymer), and PVDF-CTFE (polyvinylidene fluoride-chlorotrifluoroethylene copolymer).

[0014] Preferably, in step (2), the lithium salt is LiFSI, LiTFSI, LiNO 3 、LiClO 4 One or more of .

[0015] Preferably, in step (2), solvent 1 is one or both of N,N-dimethylformamide (DMF) and N-methylpyrrolidone (NMP).

[0016] Preferably, in step (2), the mass of the modified NiCoMn-MOF material is 50-100% of the mass of the polymer; and the mass ratio of the polymer to the lithium salt is (80-110):(90-110).

[0017] Preferably, in step (2), the mass volume of the polymer and the solvent 1 is (80-110) g: (0.5-1.5) L.

[0018] In a second aspect, the present invention provides a solid electrolyte slurry prepared by the aforementioned preparation method.

[0019] In a third aspect, the present invention provides a solid electrolyte prepared using the aforementioned solid electrolyte slurry.

[0020] In a fourth aspect, the present invention provides a solid-state battery comprising the aforementioned solid-state electrolyte.

[0021] Preferably, the positive electrode active material of the solid-state battery is NCM622 (Ni 0.6 Co 0.2 Mn 0.2 O 2 ).

[0022] Specifically, a method for preparing a solid-state battery comprises the following steps:

[0023] Step S1: NCM622 positive electrode material, conductive agent, binder, lithium salt and solvent 2 are stirred and mixed, and then coated on the surface of metal foil, and dried to obtain a positive electrode sheet;

[0024] Step S2: coating the solid electrolyte slurry on the surface of the positive electrode plate, and obtaining a solid electrolyte-positive electrode composite material after drying; assembling the solid electrolyte-positive electrode composite material and the negative electrode into a solid-state battery.

[0025] Preferably, in step S1, the binder is one or two of PVDF-HFP (polyvinylidene fluoride-hexafluoropropylene copolymer) and PVDF-CTFE (polyvinylidene fluoride-chlorotrifluoroethylene copolymer); the conductive agent is one or more of Super P, acetylene black, and carbon nanotubes; the lithium salt is LiFSI, LiTFSI, LiNO 3 、LiClO 4 One or more of; solvent 2 is one or two of N,N-dimethylformamide (DMF) and N-methylpyrrolidone (NMP).

[0026] Preferably, in step S1, the mass ratio of NCM622 positive electrode material to conductive agent is 1:(0.38~0.42); the mass ratio of NCM622 positive electrode material to binder and lithium salt is 1:(0.28~0.32):(0.28~0.32); the total mass ratio of NCM622 positive electrode material, conductive agent, binder and lithium salt to the mass ratio of solvent 2 is 1:(9~12).

[0027] Preferably, in step S1, the coating thickness is 150-300 μm.

[0028] Preferably, in step S2, the coating thickness is 75-125 μm.

[0029] The above one or more technical solutions of the present invention can achieve at least one of the following beneficial effects:

[0030] (1) The modified NiCoMn-MOF is added to the solid electrolyte slurry of the present invention, which can inhibit the dissolution of transition metals in the positive electrode material.

[0031] (2) In the preparation method of the modified NiCoMn-MOF of the present invention, a surfactant is added and a modified heat treatment is performed; the heat treatment can increase the degree of bonding between the NiCoMn-MOF material and the surfactant; the surfactant can improve the contact between the modified NiCoMn-MOF material and the polymer, and improve the dispersibility of the modified NiCoMn-MOF material in the polymer, thereby increasing the ionic conductivity of the solid electrolyte and improving the comprehensive electrochemical performance of the solid-state battery.

[0032] (3) The present invention directly coats the solid electrolyte slurry on the positive electrode plate, which can improve the contact between the positive electrode plate and the solid electrolyte, reduce the thickness of the single cell, and thus further improve the cycle performance of the battery.

[0033] (4) In the present invention, the active material in the solid-state battery is NCM622, and the properties of the modified NiCoMn-MOF are more similar to those of NCM622, which can further improve the electrical performance of the solid-state battery.

[0034] (5) In the method of the present invention, the component ratio of the positive electrode plate is adjusted to match the solid electrolyte, which helps to improve the cycle performance of the solid battery.

[0035] (6) The preparation method of the present invention is simple, the production conditions are green and clean, and it is easy to realize industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 The cycle performance diagram of the solid-state batteries prepared in Examples 1 to 10.

[0037] Figure 2 This is a cycle performance diagram of the solid-state batteries prepared in Comparative Examples 1 to 3.

[0038] Figure 3 This is a cycle performance diagram of the solid-state batteries prepared in Example 11 and Comparative Example 4. DETAILED DESCRIPTION

[0039] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with the accompanying drawings and preferred embodiments of the present invention, but the protection scope of the present invention is not limited to the following specific embodiments.

[0040] Unless otherwise defined, all the professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0041] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0042] Example 1

[0043] (1) Dissolve 6.0mmol nickel nitrate, 2.0mmol cobalt nitrate, 2.0mmol manganese sulfate and 0.001g dodecyltrimethylammonium bromide in 100mL ethanol and stir thoroughly to obtain solution A; dissolve 40mmol 2-methylimidazole in 100ml ethanol and stir thoroughly to obtain solution B; under stirring, pour all solution A into solution B quickly, mix, and continue stirring for 18h. After the reaction is completed, centrifuge, wash and dry the reaction solution to obtain Ni 60 Co 20 Mn 20 -MOF materials; Ni 60 Co 20 Mn 20 -MOF material was kept at 200°C for 80 min in an air atmosphere to obtain a modified MOF material.

[0044] (2) 0.75 g of the modified MOF material prepared in step (1), 1.0 g of LiFSI, 1.0 g of PVDF-HFP and 10 ml of DMF were thoroughly stirred and mixed to obtain a solid electrolyte slurry.

[0045] (3) Add 0.5 g single crystal NCM622 positive electrode material, 0.2 g Super P, 0.15 g PVDF-HFP, and 0.15 g LiFSI to 10 g NMP, stir and mix thoroughly to obtain a slurry; use a 200 μm thick scraper to evenly coat the slurry on the surface of the aluminum foil, and after drying, obtain a positive electrode sheet.

[0046] (4) The solid electrolyte slurry in step (2) is evenly coated on the positive electrode sheet obtained in step (3) using a 100 μm thick scraper, and after drying, a solid electrolyte-positive electrode composite material is obtained.

[0047] (5) The solid electrolyte-positive electrode composite material and lithium foil prepared in step (4) are cut into discs with a diameter of 16 mm respectively; in a glove box filled with argon atmosphere and having a water content and an oxygen content both lower than 0.01 ppm, the solid electrolyte-positive electrode composite discs and the lithium foil negative electrode discs are assembled into CR2032 button cells.

[0048] Comparative Example 1

[0049] The process is basically the same as Example 1, except that dodecyltrimethylammonium bromide is not added in step (1) of this comparative example.

[0050] Comparative Example 2

[0051] The same as Example 1, except that: in step (1) of this comparative example, no heating and heat preservation step is performed, and the corresponding prepared Ni 60 Co 20 Mn 20 -MOF material is added in step (2).

[0052] Comparative Example 3

[0053] The method is basically the same as Example 1, except that no modified MOF material is added to the solid electrolyte slurry; the specific preparation method is:

[0054] (1) 1.0 g LiFSI, 1.0 g PVDF-HFP and 10 ml DMF were thoroughly stirred and mixed to obtain a solid electrolyte slurry.

[0055] (2) Add 0.5 g single crystal NCM622 positive electrode material, 0.2 g Super P, 0.15 g PVDF-HFP, and 0.15 g LiFSI to 10 g NMP, stir and mix thoroughly to obtain a slurry; use a 200 μm thick scraper to evenly coat the slurry on the surface of aluminum foil, and after drying, obtain a positive electrode sheet.

[0056] (3) The solid electrolyte slurry in step (1) is evenly coated on the positive electrode sheet obtained in step (2) using a 100 μm thick scraper, and after drying, a solid electrolyte-positive electrode composite material is obtained.

[0057] (4) The solid electrolyte-positive electrode composite material and lithium foil prepared in step (3) are cut into discs with a diameter of 16 mm respectively; in a glove box filled with argon atmosphere and having a water content and an oxygen content both lower than 0.01 ppm, the solid electrolyte-positive electrode composite discs and the lithium foil negative electrode discs are assembled into CR2032 button cells.

[0058] Example 2

[0059] The process is basically the same as Example 1, except that the amount of dodecyltrimethylammonium bromide added in step (1) is 0.0008 g.

[0060] Example 3

[0061] The method is basically the same as Example 1, except that the amount of dodecyltrimethylammonium bromide added in step (1) is 0.0013 g.

[0062] Example 4

[0063] The same as Example 1, except that in step (1), Ni 60 Co 20 Mn 20 -MOF material was kept at 180℃ for 80min in air atmosphere.

[0064] Example 5

[0065] The same as Example 1, except that in step (1), Ni 60 Co 20 Mn 20 -MOF material was kept at 250°C for 80 min in air atmosphere.

[0066] Example 6

[0067] The method is basically the same as Example 1, except that the composition of the positive electrode material in step (3) is: 0.5 g single crystal NCM622 positive electrode material, 0.19 g Super P, 0.14 g PVDF-HFP, and 0.14 g LiFSI.

[0068] Example 7

[0069] The method is basically the same as Example 1, except that the composition of the positive electrode material in step (3) is: 0.5 g single crystal NCM622 positive electrode material, 0.21 g Super P, 0.16 g PVDF-HFP, and 0.16 g LiFSI.

[0070] Example 8

[0071] The method is basically the same as Example 1, except that the composition of the positive electrode material in step (3) is: 0.5 g single crystal NCM622 positive electrode material, 0.0625 g Super P, 0.0625 g PVDF-HFP, and 0.15 g LiFSI.

[0072] Example 9

[0073] (1) Dissolve 6.5mmol nickel nitrate, 1.5mmol cobalt nitrate, 2.0mmol manganese sulfate and 0.001g sodium dodecyl sulfate in 100mL ethanol and stir thoroughly to obtain solution A; dissolve 50mmol imidazole in 100ml ethanol and stir thoroughly to obtain solution B; under stirring, pour all solution A into solution B quickly, mix, and continue stirring for 24h. After the reaction is completed, centrifuge, wash and dry the reaction solution to obtain Ni 65 Co 15 Mn 20 -MOF materials; Ni 65 Co 15 Mn 20 -MOF material was kept at 220°C for 60 min in an air atmosphere to obtain a modified MOF material.

[0074] (2) 0.5 g of the modified MOF material prepared in step (1), 1.1 g of LiTFS, 1.0 g of PVDF-CTFE and 10 ml of DMF were mixed and stirred until the mixture was uniform to obtain a solid electrolyte slurry.

[0075] (3) Add 0.5 g single crystal NCM622 positive electrode material, 0.2 g acetylene black, 0.15 g PVDF-CTFE, and 0.15 g LiTFS to 10 g NMP, stir and mix thoroughly to obtain a slurry, and evenly coat the slurry on the surface of aluminum foil with a 300 μm thick scraper. After drying, a positive electrode sheet is obtained.

[0076] (4) The solid electrolyte slurry in step (2) is evenly coated on the positive electrode sheet obtained in step (3) using a 125 μm thick scraper, and after drying, a solid electrolyte-positive electrode composite material is obtained.

[0077] (5) The solid electrolyte-positive electrode composite material and lithium foil prepared in step (4) are cut into discs with a diameter of 16 mm respectively; in a glove box filled with argon atmosphere and having a water content and an oxygen content both lower than 0.01 ppm, the solid electrolyte-positive electrode composite discs and the lithium foil negative electrode discs are assembled into CR2032 button cells.

[0078] Example 10

[0079] (1) Dissolve 5.5mmol nickel nitrate, 2.0mmol cobalt nitrate, 2.5mmol manganese sulfate and 0.001g n-octyltrimethylammonium bromide in 100mL methanol and stir thoroughly to obtain solution A; dissolve 30mmol 2-methylimidazole in 100ml methanol and stir thoroughly to obtain solution B; under stirring, pour all solution A into solution B quickly, mix, and continue stirring for 24h. After the reaction is completed, centrifuge, wash and dry the reaction solution to obtain Ni 55 Co 20 Mn 25 -MOF materials; Ni 55 Co 20 Mn 25 -MOF material was kept at 190°C for 100 min in an air atmosphere to obtain a modified MOF material.

[0080] (2) 0.85 g of the modified MOF material prepared in step (1), 0.9 g of LiFSI, 1.1 g of PVDF-HFP and 10 ml of DMF were mixed and stirred until the mixture was uniform to obtain a solid electrolyte slurry.

[0081] (3) Add 0.5 g single crystal NCM622 positive electrode material, 0.2 g Super P, 0.15 g PVDF-HFP, and 0.15 g LiFSI to 10 g NMP, stir and mix thoroughly to obtain a slurry; use a 300 μm thick scraper to evenly coat the slurry on the surface of aluminum foil, and after drying, obtain a positive electrode sheet.

[0082] (4) The solid electrolyte slurry in step (2) is evenly coated on the positive electrode sheet in step (3) using a 125 μm thick scraper, and after drying, a solid electrolyte-positive electrode composite material is obtained.

[0083] (5) The solid electrolyte-positive electrode composite material and lithium foil prepared in step (4) are cut into discs with a diameter of 16 mm respectively; in a glove box filled with argon atmosphere and having a water content and an oxygen content both lower than 0.01 ppm, the solid electrolyte-positive electrode composite discs and the lithium foil negative electrode discs are assembled into CR2032 button cells.

[0084] Embodiment 11

[0085] (1) Dissolve 6.0mmol nickel nitrate, 2.0mmol cobalt nitrate, 2.0mmol manganese sulfate and 0.001g dodecyltrimethylammonium bromide in 100mL ethanol and stir thoroughly to obtain solution A; dissolve 40mmol 2-methylimidazole in 100ml ethanol and stir thoroughly to obtain solution B; under stirring, pour all solution A into solution B quickly, mix, and continue stirring for 18h. After the reaction is completed, centrifuge, wash and dry the reaction solution to obtain Ni 60 Co 20 Mn 20 -MOF materials; Ni 60 Co 20 Mn 20 -MOF material was kept at 200°C for 80 min in an air atmosphere to obtain a modified MOF material.

[0086] (2) 0.75 g of the modified MOF material prepared in step (1), 1.0 g of LiFSI, 1.0 g of PVDF-HFP and 10 ml of DMF were fully stirred and mixed to obtain a solid electrolyte slurry;

[0087] (3) Add 0.5 g single crystal NCM811 positive electrode material, 0.2 g Super P, 0.15 g PVDF-HFP, and 0.15 g LiFSI to 10 g NMP, stir and mix thoroughly to obtain a slurry; use a 200 μm thick scraper to evenly coat the slurry on the surface of the aluminum foil, and after drying, obtain a positive electrode sheet.

[0088] (4) The solid electrolyte slurry in step (2) is evenly coated on the positive electrode sheet obtained in step (3) using a 100 μm thick scraper, and after drying, a solid electrolyte-positive electrode composite material is obtained.

[0089] (5) The solid electrolyte-positive electrode composite material and lithium foil prepared in step (4) are cut into discs with a diameter of 16 mm respectively; in a glove box filled with argon atmosphere and having a water content and an oxygen content both lower than 0.01 ppm, the solid electrolyte-positive electrode composite discs and the lithium foil negative electrode discs are assembled into CR2032 button cells.

[0090] Comparative Example 4

[0091] It is basically the same as Comparative Example 3, except that the positive electrode active material is a single crystal NCM811 positive electrode material.

[0092] The CR2032 button cells prepared in Examples 1 to 11 and Comparative Examples 1 to 4 were aged for 12 hours and then cycled 100 times at a voltage of 2.8 to 4.5 V and a current density of 0.5 C. The test results show that Figures 1 to 3 , specific data can be seen in Table 1.

[0093] Table 1

[0094]

[0095] from Figure 1~2 As can be seen from Table 1, the specific capacity and cycle performance of the solid-state battery in Example 1 are significantly better than those in Comparative Example 1, indicating that the addition of surfactants can effectively improve the electrochemical performance of solid-state batteries. The specific capacity and cycle performance of the solid-state battery in Example 1 are significantly better than those in Comparative Example 2, indicating that the thermal insulation modification treatment can effectively improve the electrochemical performance of solid-state batteries. The specific capacity and cycle performance of the solid-state battery in Example 1 are significantly better than those in Comparative Example 3, indicating that the addition of modified MOF materials can effectively improve the electrochemical performance of solid-state batteries.

[0096] In Examples 1 to 3, the addition amount of the surfactant is different, and the specific capacity and cycle performance of the corresponding solid-state batteries prepared will fluctuate to a certain extent, but all have good electrochemical properties.

[0097] The main reason for the different temperatures of the heat preservation treatment in Example 1 and Examples 4-5 is that the specific capacity and cycle performance of the corresponding solid-state batteries prepared will fluctuate to a certain extent, but all have good electrochemical properties.

[0098] In Examples 1 and 6-7, the proportions of the components in the positive electrode sheet were slightly adjusted, and the specific capacity and cycle performance of the corresponding solid-state batteries prepared therefrom will fluctuate to a certain extent. In Example 8, the proportions of the components in the positive electrode sheet adopt the currently conventional proportions, and the specific capacity and cycle performance of the corresponding solid-state batteries prepared therefrom will decrease to a certain extent.

[0099] In Examples 9 and 10, the main difference is that the preparation process of the solid-state battery has certain changes, and the cycle performance and discharge capacity of the corresponding solid-state batteries will also fluctuate to a certain extent.

[0100] from Figure 3 As can be seen from Table 1, compared with Example 1, Example 11 mainly replaces the positive electrode active material, and its capacity retention rate is lower than that of Example 1; however, compared with Comparative Example 4, the cycle performance of Example 11 is greatly improved.

[0101] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a solid electrolyte slurry, characterized in that: The following steps are involved: (1) dissolving nickel salt, cobalt salt, manganese salt and surfactant in a solvent to obtain solution A; The ligand is dissolved in a solvent to obtain a solution B; the solution A is added to the solution B for reaction, and after the reaction is completed, a NiCoMn-MOF material is obtained; the NiCoMn-MOF material is heated and maintained in an oxygen-containing atmosphere for modification to obtain a modified NiCoMn-MOF material; (2) mixing the modified NiCoMn-MOF material prepared in step (1), lithium salt, polymer and solvent 1 to obtain a solid electrolyte slurry; Wherein: solvent 1 is one or two of DMF and NMP; the heating and insulation temperature is 180-250° C., and the heating and insulation time is 30-120 min.

2. The method for preparing a solid electrolyte slurry according to claim 1, characterized in that: In the step (1), the nickel salt is one or more of nickel nitrate, nickel sulfate, and nickel chloride; the cobalt salt is one or more of cobalt nitrate, cobalt sulfate, and cobalt chloride; the manganese salt is one or more of manganese nitrate, manganese sulfate, and manganese chloride; and the nickel salt, cobalt salt, and manganese salt are added in a molar ratio of Ni, Co, and Mn of (55-65):(15-25):(15-25).

3. The method for preparing a solid electrolyte slurry according to claim 1, characterized in that: In the step (1), the surfactant is one or more of dodecyltrimethylammonium bromide, n-octyltrimethylammonium bromide, sodium dodecylbenzenesulfonate, and sodium dodecyl sulfate; the mass ratio of the total molar number of Ni, Co and Mn in the nickel salt, cobalt salt and manganese salt to the surfactant is (85-115) mmol: (0.008-0.013) g; The ligand is one or two of imidazole and 2-methylimidazole; the ratio of the total molar number of Ni, Co and Mn in the nickel salt, cobalt salt and manganese salt to the molar number of the ligand is (85-115):(350-500); The solvent is one or more of methanol, ethanol and water.

4. The method for preparing a solid electrolyte slurry according to any one of claims 1 to 3, characterized in that: In the step (1), the reaction time is 12 to 24 hours.

5. The method for preparing a solid electrolyte slurry according to claim 1, characterized in that: In the step (2), the polymer is one or more of PVDF, PVDF-HFP, and PVDF-CTFE; The lithium salt is one or more of LiFSI, LiTFSI, LiNO3, and LiClO4; The mass of the modified NiCoMn-MOF material is 50~100% of the mass of the polymer; the mass ratio of the polymer to the lithium salt is (80~110):(90~110).

6. A solid electrolyte slurry, characterized in that: The method is prepared according to any one of claims 1 to 5.

7. A solid-state battery, characterized in that: The solid electrolyte in the solid-state battery is prepared using the solid electrolyte slurry described in claim 6.

8. A method for preparing a solid-state battery according to claim 7, characterized in that: The following steps are involved: Step S1: After mixing NCM622 positive electrode material, conductive agent, binder, lithium salt and solvent 2, the mixture is coated on the surface of metal foil and dried to obtain a positive electrode sheet; Step S2: applying the solid electrolyte slurry to the surface of the positive electrode plate, and after drying, obtaining a solid electrolyte-positive electrode composite material; assembling the solid electrolyte-positive electrode composite material and the negative electrode into a solid-state battery.

9. The method for preparing a solid-state battery according to claim 8, characterized in that: In the step S1, The binder is one or two of PVDF-HFP and PVDF-CTFE; The conductive agent is one or more of SuperP, acetylene black, and carbon nanotubes; The lithium salt is one or more of LiFSI, LiTFSI, LiNO3, and LiClO4; Solvent 2 is one or two of DMF and NMP; The mass ratio of NCM622 positive electrode material to conductive agent is 1:(0.38~0.42); the mass ratio of NCM622 positive electrode material to binder and lithium salt is 1:(0.28~0.32):(0.28~0.32); the mass ratio of the total mass of NCM622 positive electrode material, conductive agent, binder and lithium salt to the mass ratio of solvent 2 is 1:(9~12).

10. The method for preparing a solid-state battery according to claim 8, characterized in that: In the step S1, the coating thickness is 150-300 μm; In the step S2, the coating thickness is 75-125 μm.

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