Composite mof materials, separators, methods of preparation, batteries, and applications

Abstract

The application belongs to the technical field of novel MOF materials, and particularly relates to a composite MOF material, a diaphragm, a preparation method, a battery and application. Raw materials of the composite MOF material include an oxide solid electrolyte, an organic ligand and a lithium supplementing agent. A chemical general formula of the oxide solid electrolyte is as follows: Li x La y A z B e O 12 ; wherein, 0 + The composite MOF material provided by the application improves the conduction performance, structural stability and mechanical strength of the MOF material to lithium ions (Li

Description

Technical Field

[0001] The present invention belongs to the technical field of battery materials, and in particular relates to a composite MOF material, a diaphragm, a preparation method, a battery and applications. Background Art

[0002] Metal-Organic Framework (MOF) materials, due to their unique structure and properties, have shown broad application potential in a variety of fields, including gas adsorption, gas separation, gas storage, and catalysis. MOF materials have attracted widespread attention in battery materials due to their advantages, such as high specific surface area, tunable pore structure, and diverse chemical functions (ion conduction, electron conduction, and catalytic activity).

[0003] However, the poor intrinsic conductivity of most existing MOFs limits their application in electrode materials. Some MOFs can experience structural collapse or degradation under battery operating conditions (such as high voltage and strong acid / alkaline environments), affecting their long-term stability. MOFs generally have low mechanical strength and may experience volume expansion or structural damage during battery charge and discharge, leading to performance degradation. In summary, MOFs face significant limitations in battery applications due to their poor conductivity, stability, and mechanical strength. Summary of the Invention

[0004] To address the above issues, the present invention provides a composite MOF material, a separator, a preparation method, a battery, and applications. The composite MOF material combines MOF and an oxide electrolyte, resulting in high electrical conductivity, structural stability, and mechanical strength. The preparation method of the composite MOF material can uniformly embed the oxide electrolyte into the MOF, thereby improving the performance of the MOF material.

[0005] The present invention is achieved through the following technical solutions:

[0006] In a first aspect, the present invention provides a composite MOF material, the raw materials of which include an oxide solid electrolyte, an organic ligand and a lithium supplement agent;

[0007] The mass ratio of the organic ligand, the lithium replenisher and the oxide solid electrolyte is (2-9):1:(1-7).

[0008] In some possible implementations, the general chemical formula of the oxide solid electrolyte is as follows:

[0009] Li x La y A z B e O 12 ;

[0010] Wherein, 0<x≤7, 0<y≤3, 1≤z≤4, 0≤e≤1, A is at least one element of Group IVB, and B is at least one element of Group VB.

[0011] In a second aspect, the present invention provides a method for preparing the above-mentioned composite MOF material, comprising the following steps:

[0012] The mixture is subjected to a solvothermal reaction, and then washed, dried and calcined to obtain a composite MOF material;

[0013] The mixture includes the organic ligand, the lithium supplement agent and the oxide solid electrolyte.

[0014] In some possible implementations, preparing the mixture comprises the following steps:

[0015] The organic ligand is mixed with a solvent, and then mixed with a lithium supplement agent and an oxide solid electrolyte to obtain a mixture.

[0016] In a third aspect, the present invention provides a diaphragm, comprising a base film and a first coating layer applied on a surface of the base film;

[0017] The active material in the first coating layer includes the composite MOF material mentioned above.

[0018] In some possible implementations, the diaphragm further includes a second coating;

[0019] The second coating layer is applied to the surface of the base film that is away from the base film.

[0020] In some possible implementations, the active material in the second coating layer includes at least one of the composite MOF material, polyvinylidene fluoride, polymethyl methacrylate, polyvinylidene fluoride-hexafluoropropylene copolymer, polyaniline, polyethylene oxide, and aramid.

[0021] In a fourth aspect, the present invention provides a method for preparing the above-mentioned diaphragm, comprising the following steps:

[0022] Applying the coating slurry on the surface of the base film;

[0023] The coating slurry contains an active material.

[0024] In a fifth aspect, the present invention provides a battery, wherein the separator of the battery includes the separator described above.

[0025] In a sixth aspect, the present invention provides an application of the composite MOF material provided above in the field of battery material technology.

[0026] Compared with the prior art, the composite MOF material, diaphragm, preparation method, and battery provided by the present invention have at least the following beneficial technical effects:

[0027] (1) The composite MOF material provided by the present invention is a composite of MOF material and oxide solid electrolyte in situ, so that the composite MOF material has a high lithium ion (Li + )'s conductivity, structural stability and mechanical strength.

[0028] (2) The preparation method of the composite MOF material provided by the present invention can generate the precursor of the composite MOF material in situ, and then obtain the composite MOF material through impurity removal, drying and calcination. While improving the conductivity, structural stability and mechanical strength of the composite MOF material, it simplifies the production steps. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present drawings or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present drawings. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0030] Figure 1 This is an XRD pattern of a composite MOF material provided in Example 1 of the present invention;

[0031] Figure 2 This is an XRD pattern of a lithium lanthanum zirconium oxide doped MOF material provided in Comparative Example 2 of the present invention;

[0032] Figure 3 This is an electrochemical impedance spectroscopy graph of a composite MOF material provided in Example 1 of the present invention;

[0033] Figure 4 This is an electrochemical impedance spectroscopy diagram of a lithium lanthanum zirconium oxide doped MOF material provided in Comparative Example 2 of the present invention.

[0034] The purpose, features and advantages of this drawing will be further described with reference to the accompanying drawings in conjunction with the embodiments. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is described and illustrated below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention. Based on the embodiments provided by the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present invention.

[0036] Obviously, the following descriptions are merely examples or embodiments of the present invention, and those skilled in the art will be able to apply the present invention to other similar scenarios without inventive effort. Furthermore, it is understood that while the effort involved in such a development process may be complex and lengthy, for those skilled in the art related to the present disclosure, any design, manufacturing, or production changes based on the technical content disclosed in the present disclosure are merely conventional technical means and should not be construed as an inadequacy of the present disclosure.

[0037] However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters or repeated descriptions of substantially identical structures may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art. Furthermore, the following description is provided to facilitate a thorough understanding of the present invention by those skilled in the art and is not intended to limit the subject matter recited in the claims.

[0038] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form a new technical solution, and all technical features and optional technical features of the present invention can be combined with each other to form a new technical solution.

[0039] The following is a detailed description of a composite MOF material and a preparation method, and a lithium-ion battery according to an embodiment of the present invention.

[0040] A first aspect of an embodiment of the present invention provides a composite MOF material, the raw materials of which include an oxide solid electrolyte, an organic ligand, and a lithium supplement agent;

[0041] The mass ratio of the organic ligand, lithium replenisher and oxide solid electrolyte is (2~9):1:(1~7).

[0042] In some embodiments, the oxide solid electrolyte has the following chemical formula:

[0043] Li x La y A z B e O 12 ;

[0044] Wherein, 0<x≤7, 2<y≤3, 1≤z≤4, 0≤e≤1, A is at least one element of Group IVB, and B is at least one element of Group VB.

[0045] The composite MOF material provided by the embodiment of the present invention has a large number of microporous structures, which is conducive to storing more lithium. The composite MOF material has a large specific surface area and can shorten the diffusion path of lithium ions; Li +It can be inserted and removed from all directions during the charge and discharge process, which improves the + The composite MOF material provided by the embodiment of the present invention comprehensively improves the diffusion rate of the MOF material to lithium ions (Li + )'s conductivity, structural stability and mechanical strength.

[0046] In some embodiments, the oxide solid electrolyte has the following chemical formula:

[0047] Li x La y A z B e O 12 ;

[0048] Wherein, 0<x<2, 2<y<8 / 3, 1≤z≤4, 0≤e≤1, A is at least one element of Group IVB, and B is at least one element of Group VB.

[0049] In some embodiments, the oxide solid electrolyte has the following chemical formula:

[0050] Li x La y A z B e O 12 ;

[0051] Wherein, 2≤x<4, 2 / 3≤y≤2, 1≤z≤4, 0≤e≤1, A is at least one element of Group IVB, and B is at least one element of Group VB.

[0052] In some embodiments, the oxide solid electrolyte has the following chemical formula:

[0053] Li x La y A z B e O 12 ;

[0054] Wherein, 4≤x<6, 0<y<2 / 3, 1≤z≤4, 0≤e≤1, A is at least one element of Group IVB, and B is at least one element of Group VB.

[0055] In some embodiments, the oxide solid electrolyte has the following chemical formula:

[0056] Li x La y A z B e O 12 ;

[0057] wherein 6≤x≤7, 8 / 3≤y≤3, 1≤z≤4, 0≤e≤1, A is at least one of Group IVB elements, and B is at least one of Group VB elements.

[0058] In some embodiments, the oxide solid state electrolyte has a chemical formula as follows:

[0059] Li x La y A z B e O 12 ;

[0060] wherein 6≤x≤7, 8 / 3≤y≤3, 1≤z<4, 0≤e≤1, A is at least one of Group IVB elements, and B is at least one of Group VB elements.

[0061] In some embodiments, the oxide solid state electrolyte has a chemical formula as follows:

[0062] Li x La y AB e O 12 ;

[0063] wherein 0<x<2, 2<y<8 / 3, 0≤e≤1, A is at least one of Group IVB elements, and B is at least one of Group VB elements.

[0064] In some embodiments, the oxide solid state electrolyte has a chemical formula as follows:

[0065] LiLa y A z B e O 12 ;

[0066] wherein 0<y≤1 / 3, 1≤z≤4, 0≤e≤1, A is at least one of Group IVB elements, and B is at least one of Group VB elements.

[0067] In some embodiments, the oxide solid state electrolyte has a chemical formula as follows:

[0068] Li 6.4 La y A z B e O 12 ;

[0069] wherein 1 / 3<y≤3, 1≤z≤4, 0≤e≤1, A is at least one of Group IVB elements, and B is at least one of Group VB elements.

[0070] In some embodiments, the oxide solid state electrolyte has a chemical formula as follows:

[0071] Li7La y A z B e O 12 ;

[0072] Wherein, 1 / 3<y≤3, 1≤z≤4, 0≤e≤1, A is at least one element of Group IVB, and B is at least one element of Group VB.

[0073] In some embodiments, the oxide solid electrolyte has the following chemical formula:

[0074] Li x La3A z B e O 12 ;

[0075] Wherein, 6≤x≤7, 1≤z≤4, 0≤e≤1, A is at least one element of Group IVB, and B is at least one element of Group VB.

[0076] In some embodiments, the oxide solid electrolyte has the following chemical formula:

[0077] Li x La y AB e O 12 ;

[0078] Wherein, 0<x<1.75, 0<y<0.75, 0≤e≤1, A is at least one element of Group IVB, and B is at least one element of Group VB.

[0079] In some embodiments, the oxide solid electrolyte has the following chemical formula:

[0080] Li x La y A 1.4 B e O 12 ;

[0081] Wherein, 4≤x<7, 0.75≤y≤3, 0≤e≤1, A is at least one element of Group IVB, and B is at least one element of Group VB.

[0082] In some embodiments, the oxide solid electrolyte has the following chemical formula:

[0083] Li x La y A2B e O 12 ;

[0084] Wherein, 6≤x≤7, 0<y≤3, 0≤e≤1, A is at least one element of Group IVB, and B is at least one element of Group VB.

[0085] In some embodiments, the oxide solid electrolyte has the following chemical formula:

[0086] Li x La y A3B e O 12 ;

[0087] Wherein, 6≤x≤7, 0<y≤3, 0≤e≤1, A is at least one element of Group IVB, and B is at least one element of Group VB.

[0088] In some embodiments, the oxide solid electrolyte has the following chemical formula:

[0089] Li x La y A4O 12 ;

[0090] Wherein, 0<x<2, 1 / 2<y<2 / 3, and A is at least one element of Group IVB.

[0091] In some embodiments, the oxide solid electrolyte has the following chemical formula:

[0092] Li x La y A z B 0.6 O 12 ;

[0093] Wherein, 6≤x≤7, 8 / 3≤y≤3, 1≤z≤4, A is at least one element of Group IVB, and B is at least one element of Group VB.

[0094] In some specific embodiments, the oxide solid electrolyte is Li7La3Zr2O 12 (LLZO).

[0095] In some specific embodiments, the oxide solid electrolyte is Li 5.75 La 0.75 TiO 12 (LLTO).

[0096] In some specific embodiments, the oxide solid electrolyte is Li 6.4 La3Zr 1.4 Ti 0.6 O 12 (LLZTO).

[0097] In some embodiments, the organic ligand includes at least one of trimesic acid (H3BTC), 2-methylimidazole (2-Methylimidazole), terephthalic acid (H2BDC), 2,5-dihydroxyterephthalic acid (H4DOBDC), and 3,3',5,5'-biphenyltetracarboxylic acid (H4ABTC).

[0098] In some embodiments, the lithium supplement comprises at least one of lithium nitrate, lithium chloride, and lithium acetate.

[0099] A second aspect of an embodiment of the present invention provides a method for preparing the above-mentioned composite MOF material, comprising the following steps:

[0100] S10. The mixture is subjected to a solvothermal reaction, followed by washing, drying, and calcining to obtain a composite MOF material;

[0101] The mixture contains an organic ligand, a lithium supplement and an oxide solid electrolyte.

[0102] The method for preparing a composite MOF material provided in an embodiment of the present invention first prepares a mixture of an organic ligand, a lithium replenisher, and an oxide solid electrolyte, and then conducts a solvothermal reaction. The coordinated metal ions (Group IVB or Group VB) in the oxide solid electrolyte are released and react with the organic ligand to form a MOF structure. The lithium in the lithium replenisher is used to compensate for defects caused by the release of Group IVB elements from the solid electrolyte, thereby generating a precursor for the composite MOF material in situ in a single step. The precursor is then washed, dried, and calcined, improving the conductivity, structural stability, and mechanical strength of the composite MOF material while simplifying the production process. Furthermore, the composite MOF material produced by the method provided in an embodiment of the present invention has a well-defined pore structure, which can increase the ion diffusion rate and, in turn, the cycling stability of the battery.

[0103] In some embodiments, in the above step S10, the mixture further comprises a solvent, and the solvent comprises at least one of methanol, N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), ethanol, and chloroform.

[0104] In some embodiments, in the above step S10, preparing the mixture comprises the following steps:

[0105] S101. After mixing the organic ligand with the solvent, the mixture is mixed with the lithium supplement agent and the oxide solid electrolyte to obtain a mixture.

[0106] In some embodiments, in the above step S101 , the mass volume ratio of the organic ligand to the solvent is (3.1 g to 5 g): 1 ml.

[0107] In some embodiments, in step S101, the stirring speed of the mixture with the lithium supplement and the oxide solid electrolyte is 490 rpm to 510 rpm and the stirring time is 4 hours to 6 hours. In this case, the obtained mixture has uniform composition and no agglomeration.

[0108] In some embodiments, in the above step S10, in the solvent thermal reaction, the reaction temperature is 120° C. to 150° C., and the reaction time is 24 h to 36 h.

[0109] In some embodiments, in the above step S10, the washing step includes:

[0110] S102. Centrifuge the solvent thermal reaction product to obtain a precipitate, and wash it with a detergent.

[0111] In some embodiments, in step S102, the detergent washing step includes an alcohol wash followed by a water wash. In this case, alcohol is first used to remove unreacted metal salts or ligands, and then deionized water is used to form defects, thereby increasing the charge transfer capacity. It should be noted that the amount of alcohol or water used for washing depends on the amount of precipitate obtained during actual preparation and is not particularly limited in the present embodiments. However, as an example, the amount of alcohol or water used in a single wash can be 2 to 5 times the amount of precipitate.

[0112] In some embodiments, the alcohol washing step includes: mixing the alcohol and the precipitate and then centrifuging and separating the mixture to obtain the precipitate for the next washing step.

[0113] In some embodiments, the number of alcohol washes is at least 3 times.

[0114] In some embodiments, the alcohol is C 1~4 of alcohol.

[0115] In some embodiments, the water washing step includes: mixing water and the precipitate after alcohol washing and then centrifuging to obtain the precipitate for the next washing step.

[0116] In some embodiments, the number of water washes is at least 1.

[0117] It should be noted that the rotation speed of centrifugal separation is conventional in the art and is not particularly limited in the embodiments of the present invention.

[0118] In some embodiments, in the above step S10, the drying temperature is 85°C to 90°C.

[0119] In some embodiments, in the above step S10, the drying time is 8 hours to 9 hours. It should be noted that the drying time is only an example of the embodiment of the present invention, and an appropriate drying time can be selected according to the amount of the product during actual preparation.

[0120] In some specific embodiments, in the above step S10, the drying conditions are: vacuum drying, temperature of 85° C. to 90° C., and time of 8 h to 9 h.

[0121] In some embodiments, in the calcination step in step S10, the calcination atmosphere is an inert gas, and the calcination temperature is 490°C to 510°C.

[0122] In some embodiments, in the calcination step in step S10, the calcination time is 3 hours to 4 hours.

[0123] In some embodiments, the inert gas includes at least one of argon, helium, and neon.

[0124] A third aspect of an embodiment of the present invention provides a diaphragm, comprising a base film and a first coating layer coated on a surface of the base film;

[0125] The active material in the first coating layer includes the composite MOF material described above.

[0126] The diaphragm provided by the present invention has a first coating layer containing the composite MOF material provided by the present invention, and the composite MOF material can improve the diaphragm's resistance to lithium ions (Li + ) conductivity. It should be noted that the thickness of the base film, the thickness of the first coating layer, and the material of the base film are all conventional in the art and are not particularly limited in the embodiments of the present invention. However, as an example, the thickness of the base film can be 10 μm, the thickness of the first coating layer can be 3 μm, and the material of the base film can be a PE base film.

[0127] In some embodiments, the membrane further comprises a second coating;

[0128] The second coating layer is applied to the surface of the base film facing away from the first coating layer.

[0129] In this case, the separator consists of two layers of coating, which are + Similarly, it should be noted that the thickness of the second coating layer is conventional in the art and is not particularly limited in the embodiments of the present invention. However, as an example, the thickness of the second coating layer may be 3 μm.

[0130] In some embodiments, the active material in the second coating layer includes at least one of a composite MOF material, polyvinylidene fluoride, polymethyl methacrylate, polyvinylidene fluoride-hexafluoropropylene copolymer, polyaniline, polyethylene oxide, and aramid.

[0131] In some specific embodiments, the average molecular weight of polyvinylidene fluoride is 390,000 to 410,000, preferably 400,000.

[0132] In some specific embodiments, the average molecular weight of polymethyl methacrylate is 90,000 to 110,000, preferably 100,000.

[0133] In some embodiments, the average molecular weight of the polyvinylidene fluoride-hexafluoropropylene copolymer is 450,000-500,000, preferably 455,000.

[0134] In some embodiments, the polyaniline is an AR grade product produced by Shanghai Maklin Biochemical Technology Co., Ltd.

[0135] In some embodiments, the average molecular weight of the polyethylene oxide is 590,000-610,000, preferably 600,000.

[0136] In some embodiments, the aramid fiber is an AR grade product produced by Shanghai Maklin Biochemical Technology Co., Ltd.

[0137] The fourth aspect of the embodiment of the present application provides a preparation method of the above-mentioned diaphragm, comprising the following steps:

[0138] S1. Coating the coating slurry on the surface of the base film;

[0139] The coating slurry contains an active material of the first coating.

[0140] The preparation method of the diaphragm provided by the embodiment of the present application coats the coating slurry containing the active material on the surface of the base film, and the formed diaphragm has excellent conductive performance of lithium ion (Li + ). It should be noted that the coating conditions are conventional in the art, and do not need to be particularly limited in the embodiment of the present application, but as an example, the viscosity of the coating slurry can be 500 mPa·s-1500 mPa·s.

[0141] In some embodiments, in the above-mentioned step S1, the coating slurry contains an active material, an auxiliary agent, and a solvent. In this case, the auxiliary agent is used to disperse the active material, adjust the viscosity, wettability, etc. of the slurry. It should be noted that the auxiliary agent and the solvent are conventional in the art, and are not particularly limited in the embodiment of the present application, but as an example, the auxiliary agent generally includes at least one of a wetting agent, a plasticizer, a dispersant, a binder, an anti-settling agent, a defoaming agent, and a pore-forming agent; the solvent is an aqueous solution of sodium carboxymethyl cellulose (CMC), wherein the mass fraction of sodium carboxymethyl cellulose is 5%.

[0142] The fifth aspect of the embodiment of the present application provides a battery, wherein the diaphragm of the battery comprises the diaphragm provided by the third aspect of the embodiment of the present application.

[0143] The following is a further description of the composite MOF material and the preparation method provided by the present application in combination with specific embodiments.

[0144] Embodiment 1

[0145] Example 1 provides a composite MOF material, the raw material of which is Li7La3Zr2O 12 (LLZO), lithium nitrate and H3BTC;

[0146] Among them, H3BTC, lithium nitrate and Li7La3Zr2O 12 The mass ratio of (LLZO) is 5:1:2.9.

[0147] This embodiment also provides a method for preparing a composite MOF material, the steps of which are as follows:

[0148] S1-1. Preparation of mixture

[0149] 50g H3BTC was added to 100ml methanol and stirred until completely dissolved. Then 10g lithium nitrate and 29g Li7La3Zr2O 12 The powders were mixed and stirred for 4 h at a stirring speed of 490 rpm to obtain a mixture.

[0150] S1-2. Solvothermal reaction

[0151] The mixture was placed in a high-pressure reactor and reacted at 120° C. for 36 hours to obtain a precursor.

[0152] S1-3. Washing

[0153] The precursor was centrifuged to obtain a precipitate, which was washed four times by centrifugation with methanol and once by centrifugation with deionized water.

[0154] S1-4. Drying

[0155] The washed product was vacuum dried in a forced air drying oven at 85°C for 8 h.

[0156] S1-5. Calcination

[0157] The dried product was calcined under argon atmosphere at a temperature of 500° C. for 4 h, and then cooled to room temperature to obtain a composite MOF material.

[0158] Example 2

[0159] Example 2 provides a composite MOF material, the raw material is Li 5.75 La 0.75 TiO 12 (LLTO), lithium acetate and H2BDC;

[0160] Among them, H2BDC, lithium acetate and Li 5.75 La 0.75 TiO 12 The mass ratio of (LLTO) is 8.4:1:6.6.

[0161] This embodiment also provides a method for preparing a composite MOF material, the steps of which are as follows:

[0162] S2-1. Preparation of mixture

[0163] 42g H2BDC was added to 100ml methanol and stirred until completely dissolved. Then 5g lithium acetate and 33g Li1La were added. 1 / 3Ti1O3 powder was mixed and stirred for 5 h at a stirring speed of 500 rpm to obtain a mixture.

[0164] S2-2. Solvothermal reaction

[0165] The mixture was placed in a high-pressure reactor and reacted at 150° C. for 24 h.

[0166] S2-3. Washing

[0167] The solvent thermal reaction product was centrifuged to obtain a precipitate, which was washed four times by centrifugation with methanol and once by centrifugation with deionized water.

[0168] S2-4. Drying

[0169] The washed product was vacuum dried in a forced air drying oven at 90°C for 9 h.

[0170] S2-5. Calcination

[0171] The composite MOF material was obtained by calcining under argon atmosphere at a temperature of 500° C. and a calcination time of 3.5 h, and then cooling to room temperature.

[0172] Example 3

[0173] Example 3 provides a composite MOF material, the raw material is Li 6.4 La3Zr 1.4 Ta 0.6 O 12 (LLZTO), lithium chloride and H4DOBDC;

[0174] Among them, H3BTC, lithium nitrate and Li 6.4 La3Zr 1.4 Ta 0.6 O 12 The mass ratio is 2.1:1:1.

[0175] This embodiment also provides a method for preparing a composite MOF material, the steps of which are as follows:

[0176] S3-1. Preparation of mixture

[0177] 31g H4DOBDC was added to 100ml methanol and stirred until completely dissolved. Then 15g lithium chloride and 15g Li 6.4 La3Zr 1.4 Ta 0.6 O 12 The powders were mixed and stirred for 6 h at a stirring speed of 510 rpm to obtain a mixture.

[0178] S3-2. Solvothermal reaction

[0179] The mixture was placed in a high-pressure reactor and reacted at 120°C for 30 hours.

[0180] S3-3. Washing

[0181] The solvent thermal reaction product was centrifuged to obtain a precipitate, which was washed four times by centrifugation with methanol (the amount used for each time was 4 times that of the precipitate) and once by centrifugation with deionized water (the amount used was 3 times that of the precipitate).

[0182] S3-4. Drying

[0183] The washed product was vacuum dried in a forced air drying oven at 85°C for 9 h.

[0184] S3-5. Calcination

[0185] The composite MOF material was obtained by calcining under argon atmosphere at a temperature of 500° C. and a calcination time of 4 h, and then cooling to room temperature.

[0186] Comparative Example 1

[0187] Comparative Example 1 provides a method for preparing a MOF material, the steps are as follows:

[0188] D1-1. 50 g of H3BTC was added to 100 ml of methanol and stirred until completely dissolved. The mixture was then mixed with 10 g of lithium nitrate and stirred for 1 h at a stirring speed of 500 rpm to obtain a reaction mixture.

[0189] D1-2. Place the reaction mixture in a high-pressure reactor and react at 120° C. for 24 hours to obtain a MOF material precursor.

[0190] D1-3. The MOF material precursor was centrifuged to obtain a precipitate, which was then washed four times by centrifugation using methanol (the amount used for each time was 4 times that of the precipitate).

[0191] D1-4. The washed product was vacuum dried in a forced air drying oven for 8 h at a drying temperature of 85°C.

[0192] D1-5. The dried product was calcined under argon atmosphere at a temperature of 500°C for 4 h, and then cooled to room temperature to obtain a MOF material.

[0193] Comparative Example 2

[0194] Comparative Example 1 provides a method for preparing a MOF material doped with lithium lanthanum zirconium oxide, the steps are as follows:

[0195] D2-1. The MOF material prepared in Comparative Example 1, 29gLi7La3Zr2O 12 The (oxide solid electrolyte) powder was mixed with 100 ml of methanol and stirred for 1 h to obtain a suspension.

[0196] D2-2. Place the suspension in a high-pressure reactor and react at 120°C for 24 hours to obtain a MOF material precursor doped with lithium lanthanum zirconium oxide.

[0197] D2-3. The lithium lanthanum zirconium oxide-doped MOF material precursor was centrifuged to obtain a precipitate, which was then washed four times by centrifugation using methanol (the single amount was 4 times that of the precipitate).

[0198] D2-4. The washed product was vacuum dried in a forced air drying oven at 85°C for 8 h.

[0199] D2-5. The dried product was calcined under argon atmosphere at 500°C for 4 hours, and then cooled to room temperature to obtain a MOF material doped with lithium lanthanum zirconium oxide (LLZO).

[0200] In order to verify the progress of a composite MOF material and its preparation method according to the embodiment of the present invention, taking Example 1 and Comparative Example 2 as examples, the composite MOF material provided in Example 1 and the doped Li7La3Zr2O prepared by the preparation method provided in Comparative Example 2 were mixed. 12 The MOF material was subjected to XRD testing, and the obtained XRD pattern is shown in the attached manual. Figures 1 and 2 The materials provided in Example 1 and Comparative Example 2 or the materials prepared by the preparation methods were subjected to electrochemical impedance spectroscopy (EIS) testing. The electrochemical impedance spectroscopy (EIS) is shown in the attached manual. Figures 3 and 4 The materials provided in the examples and comparative examples or the materials prepared by the preparation methods were made into button batteries, and the coulombic efficiency and capacity retention of the batteries were tested on a Land tester. The test results are shown in Table 1 below.

[0201] The button cell is prepared as follows:

[0202] The materials provided by the examples and the comparative examples were made into composite separators, 1 mol / L LiPF6 (volume ratio of ethylene carbonate (EC): dimethyl carbonate (DMC): methyl ethyl carbonate (EMC) = 1:1:1) was used as the electrolyte, and the battery CR2032 button cell was assembled in an argon glove box.

[0203] The steps of making the composite separator from the materials provided by the examples and the comparative examples are as follows:

[0204] (1) The materials provided by the examples or the comparative examples were mixed to form a mixed coating slurry with a viscosity of 902 mPa·s, according to the mass ratio of the materials provided by the examples and the comparative examples: GR-508 (binder): A-6114 (dispersant): Dow Corning DC502W (wetting agent) = 1:0.1:0.03:0.02; wherein GR-508 is a binder produced by Hunan Gaorui Power Source Material Co., Ltd. with model number GR-508.

[0205] (2) The mixed coating slurry was coated on the surface of the base film and dried at 85°C for 15 min to obtain a first coating layer (thickness of 7 μm); a second coating layer (thickness of 7 μm) was prepared on the other surface of the base film by the same process, and finally a composite separator with a thickness of 21 μm was obtained.

[0206] Table 1

[0207]

[0208] From the above table and the accompanying drawings, at least the following conclusions can be drawn:

[0209] (1) The button cell made of the composite MOF material provided by the examples can maintain a high coulomb efficiency and capacity retention rate after 50 cycles, which shows that the composite MOF material provided by the examples can improve the conduction performance, structural stability and mechanical strength of lithium ions (Li + ), and effectively suppress the growth of lithium dendrites during long-term cycling of the battery.

[0210] (2) Figure 3 In the first case, the charge transfer impedance is small, the interface reaction kinetics is good, the bulk impedance is low, the intrinsic conductivity of the material is good, and the Warburg region is flat; while Figure 4 In the second case, the interface impedance is high and the ion diffusion is relatively poor. Therefore, the composite MOF material prepared by the preparation method provided by the examples has a good pore structure, which can help ion diffusion and increase the cycle stability of the battery.

[0211] Note that the present application is not limited to the above-described embodiments. The above-described embodiments are merely examples, and embodiments having substantially the same configuration as the technical idea and achieving the same effects within the scope of the technical idea of the present application are included in the technical scope of the present application. Furthermore, other modes constructed by applying various modifications that can be thought of by those skilled in the art to the embodiments or by combining part of the constituent elements of the embodiments are also included in the scope of the present application without departing from the spirit of the present application.

Claims

1. A composite MOF material, characterized in that: The raw materials include oxide solid electrolytes, organic ligands and lithium supplements; The mass ratio of the organic ligand, the lithium supplement agent and the oxide solid electrolyte is (2-9):1:(1-7); The preparation method of the composite MOF material comprises the following steps: The mixture is subjected to a solvothermal reaction, and then washed, dried and calcined to obtain a composite MOF material; The mixture consists of the organic ligand, the lithium supplement agent, the oxide solid electrolyte and a solvent; The lithium supplement comprises at least one of lithium nitrate, lithium chloride and lithium acetate.

2. The composite MOF material according to claim 1, characterized in that The general chemical formula of the oxide solid electrolyte is as follows: Li x Day y A z B e O 12 ; Wherein, 0<x≤7, 0<y≤3, 1≤z≤4, 0≤e≤1, A is at least one element of Group IVB, and B is at least one element of Group VB.

3. A method for preparing a composite MOF material, characterized in that: The method for preparing the composite MOF material according to claim 1 or 2 comprises the following steps: The mixture is subjected to a solvothermal reaction, and then washed, dried and calcined to obtain a composite MOF material; The mixture consists of the organic ligand, the lithium supplement agent, the oxide solid electrolyte and a solvent.

4. The method for preparing the composite MOF material according to claim 3, wherein: The preparation of the mixture comprises the following steps: The organic ligand is mixed with a solvent, and then mixed with a lithium supplement agent and an oxide solid electrolyte to obtain a mixture.

5. A diaphragm, characterized in that: It includes a base film and a first coating layer applied on the surface of the base film; The active material in the first coating layer comprises the composite MOF material according to claim 1 or 2.

6. The diaphragm according to claim 5, characterized in that The diaphragm further includes a second coating; The second coating layer is applied to the surface of the base film facing away from the first coating layer.

7. The diaphragm according to claim 6, characterized in that The active material in the second coating layer includes at least one of the composite MOF material, polyvinylidene fluoride, polymethyl methacrylate, polyvinylidene fluoride-hexafluoropropylene copolymer, polyaniline, polyethylene oxide, and aramid.

8. A method for preparing a diaphragm, characterized in that: The method for preparing the diaphragm according to any one of claims 5 to 7 comprises the following steps: applying the coating slurry on the base film; The coating slurry contains an active material.

9. A battery, characterized in that: The separator of the battery comprises the separator according to any one of claims 5 to 7.

10. An application of a composite MOF material, characterized in that: Use of the composite MOF material according to claim 1 or 2 in the field of battery material technology.

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