MOFs-based solid electrolyte membrane and preparation method and application thereof

Abstract

The invention belongs to the technical field of lithium ion batteries, and particularly relates to an MOFs (Metal-Organic Frameworks)-based solid electrolyte membrane as well as a preparation method and application thereof. The specific preparation method comprises the following steps: dispersing MOFs in a solvent, and adding a polymer matrix and a lithium salt after uniform dispersion to obtain a precursor solution; light-cured resin is added into the precursor solution, monomers of the light-cured resin are initiated to be polymerized through light curing under the action of a photoinitiator, chain segments of a polymer matrix are adsorbed to the surfaces of the MOFs, lithium salt is adsorbed to the surfaces of the MOFs through electrostatic interaction, and an MOFs-polymer matrix-lithium salt ternary composite interface is formed and serves as a stable Li < + > transmission network. The MOF-based solid electrolyte membrane is obtained. The prepared MOFs-based solid electrolyte membrane has good macroscopic mechanical properties and a uniform and porous surface, and can form good interface contact with an electrode, so that the stability of a battery is improved, and the cycle life of the battery is prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium-ion batteries, and in particular relates to a MOFs-based solid electrolyte membrane and a preparation method and application thereof. Background Art

[0002] Currently used lithium-ion batteries mostly use carbonate-based organic electrolytes, which are volatile and flammable. Leakage poses a potential risk of fire and explosion. During the battery cycle, the negative electrode lithium easily forms lithium dendrites in the liquid organic electrolyte, which can pierce the separator and cause a short circuit. The decomposition, volatilization, and side reactions of the organic electrolyte can also cause battery capacity decay, thereby shortening the battery life. Therefore, the development of electrolyte materials with excellent electrochemical properties and high safety is crucial to improving the safety and cycle stability of lithium-ion batteries.

[0003] Compared to liquid organic electrolytes, solid electrolytes are non-flammable and exhibit higher mechanical strength. This not only fundamentally eliminates the risk of explosion but also enhances compatibility with lithium metal, significantly improving the energy density and safety of solid-state lithium batteries.

[0004] Solid-state electrolytes are divided into two major categories: inorganic ceramics and organic polymers. Polymer electrolytes, composed of a polymer matrix and lithium salts, offer advantages such as high safety, high flexibility, ease of manufacturing and integration, and good interfacial contact with electrodes. They are considered one of the core materials for next-generation high-energy-density lithium batteries.

[0005] However, since the conduction of lithium ions is highly coupled to the segmental motion of the polymer and the polymer matrix has high crystallinity at room temperature, the room temperature ionic conductivity of polymer electrolytes is usually very low, <10 -4 S / cm, which is difficult to meet the needs of actual applications. In addition, the traditional thermosetting molding method requires high-temperature heating, high energy consumption, long curing time, and low production efficiency. Summary of the Invention

[0006] In order to solve the technical problems in the above-mentioned prior art that the room temperature ionic conductivity of polymer electrolytes is usually extremely low and difficult to meet practical application requirements, and that the traditional thermosetting molding method requires high-temperature heating, high energy consumption, long curing time, and low production efficiency, the present invention provides a MOFs-based solid electrolyte membrane and its preparation method and application.

[0007] The present invention introduces MOFs to modify the polymer matrix. After mixing MOFs, polymer matrix and lithium salt, a photocurable resin is introduced. The monomers of the photocurable resin are polymerized by photocuring, and the chain segments of the polymer matrix are adsorbed on the surface of the MOFs. The lithium salt is adsorbed on the surface of the MOFs through electrostatic action, forming a MOFs-polymer matrix-lithium salt ternary composite interface, which serves as a stable Li+ transport network and improves the conductivity of the electrolyte membrane. At the same time, the porous structure and open metal sites of the MOFs material can effectively regulate the uniform deposition of lithium ions, inhibit the formation of lithium dendrites, and thus improve the overall performance of the battery. In addition, the present invention combines UV light curing technology to make the formed electrolyte membrane have good macroscopic mechanical properties and a uniform porous surface, which can form a good interface contact with the electrodes, thereby improving the stability and cycle life of the battery.

[0008] The first object of the present invention is to provide a method for preparing a MOFs-based solid electrolyte membrane, comprising the following steps:

[0009] The MOFs are dispersed in a solvent, and after uniform dispersion, a polymer matrix and a lithium salt are added to obtain a precursor solution.

[0010] A photocurable resin is added to the precursor solution. Under the action of a photoinitiator, the monomers of the photocurable resin are polymerized by photocuring, and the chain segments of the polymer matrix are adsorbed on the surface of MOFs. The lithium salt is adsorbed on the surface of MOFs through electrostatic action, forming a MOFs-polymer matrix-lithium salt ternary composite interface, which serves as a stable Li+ transport network to obtain a MOF-based solid electrolyte membrane.

[0011] Preferably, the MOFs is one of ZIF-8, ZIF-67 and MOF-5.

[0012] Preferably, the mass of the MOFs is 1% to 10% of the mass of the polymer matrix.

[0013] Preferably, the mass of the lithium salt is 10% to 40% of the mass of the polymer matrix.

[0014] Preferably, the mass of the photocurable resin is 50% to 70% of the mass of the polymer matrix.

[0015] Preferably, the temperature for preparing the precursor solution is 40°C to 50°C.

[0016] The light curing conditions are as follows: the power of the UV light source is 3KW to 5KW, and the curing time is 1 minute to 3 minutes.

[0017] Preferably, the lithium salt is lithium perchlorate or lithium bis(trifluoromethanesulfonyl)imide.

[0018] Preferably, the polymer matrix is one of polyvinylidene fluoride-hexafluoropropylene, polyvinylidene fluoride, polyacrylonitrile, polyethylene oxide or polymethyl methacrylate. Compared to other polymer matrices, polyvinylidene fluoride-hexafluoropropylene has low crystallinity and low glass transition temperature, which allows it to maintain flexibility at room temperature and prevent brittle cracking of the electrolyte membrane. At the same time, polyvinylidene fluoride-hexafluoropropylene exhibits good electrochemical properties and flexibility, and can provide better ionic conductivity and mechanical stability. More preferably, the polymer matrix is polyvinylidene fluoride-hexafluoropropylene.

[0019] Preferably, the photocurable resin is one or more of ethoxylated trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, polyurethane acrylate, di(2-ethylhexyl) phthalate, dibasic fatty acid esters, and phthalates; and the photoinitiator is 2-hydroxy-2-methyl-1-phenyl-1-propanone.

[0020] The second object of the present invention is to provide a MOFs-based solid electrolyte membrane prepared by the above preparation method.

[0021] The third object of the present invention is to provide an application of a MOF-based solid electrolyte membrane as a solid electrolyte for lithium-ion batteries.

[0022] Preferably, the specific method for preparing a lithium ion battery is as follows:

[0023] The negative electrode sheet, the separator material, the MOFs-based solid electrolyte membrane and the positive electrode sheet are assembled in sequence to produce a lithium-ion battery.

[0024] Preferably, the positive electrode plate is prepared by the following method:

[0025] Lithium iron phosphate, polyvinylidene fluoride and conductive carbon are placed in N,N-dimethylformamide and mixed evenly to obtain a slurry; wherein the mass ratio of lithium iron phosphate, polyvinylidene fluoride and conductive carbon is 8:1:1.

[0026] The slurry is placed on a current collector and dried to obtain a positive electrode sheet.

[0027] Preferably, the current collector is aluminum foil.

[0028] Preferably, the drying temperature is 55° C. to 65° C., and the drying time is 24 hours to 48 hours.

[0029] Preferably, the negative electrode plate is a lithium plate.

[0030] Compared with the prior art, the present invention has the following technical effects:

[0031] 1. The present invention utilizes MOFs as a rigid porous framework and a polymer matrix as a flexible phase. After mixing the MOFs, polymer matrix, and lithium salt, a photocurable resin is introduced. Under the action of a photoinitiator, photocuring triggers polymerization of the photocurable resin monomers, causing the polymer matrix segments to adsorb onto the MOF surface. The lithium salt then electrostatically adsorbs onto the MOF surface, forming a MOFs-polymer matrix-lithium salt ternary composite interface that serves as a stable Li+ transport network, resulting in a MOF-based solid electrolyte membrane. Furthermore, the MOFs provide regular micropores that act as fast Li+ transport channels. The interaction between the MOFs' surface functional groups and the lithium salt promotes lithium ion dissociation. The metal active sites of the MOFs provide hopping sites for lithium ion transport within the solid electrolyte. The MOFs' effective small molecule capture capability and the strong interaction between MOF particles and polymer chains facilitate lithium ion transport, improving the conductivity of the solid electrolyte membrane. This addresses the low ionic conductivity of existing polymer electrolyte membranes.

[0032] 2. By introducing a photocurable resin and utilizing light-induced free radical polymerization, this method rapidly cures at low temperatures, avoiding the damage to the MOFs' crystal structure caused by high temperatures. Furthermore, photocuring optimizes the pore structure of the MOF-based solid electrolyte membrane, enhancing interfacial compatibility and mechanical properties, and further improving ion transport efficiency. Furthermore, the photocuring process typically takes only a few minutes, significantly reducing preparation time and significantly improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 These are SEM images of the MOFs-based solid electrolyte membrane prepared in Example 1 at different magnifications; wherein, a is a SEM image at a magnification of 5000, and b is a SEM image at a magnification of 20000.

[0034] Figure 2 Nyquist curves of the MOFs-based solid electrolyte membrane prepared in Example 1 and the polymer electrolyte membrane prepared in Comparative Example 1.

[0035] Figure 3 This is the DC polarization curve of the MOFs-based solid electrolyte membrane prepared in Example 1.

[0036] Figure 4 These are the AC impedance spectra of the MOFs-based solid electrolyte membrane prepared in Example 1 before and after polarization.

[0037] Figure 5 Electrochemical window curves of the MOFs-based solid electrolyte membrane prepared in Example 1 and the polymer electrolyte membrane prepared in Comparative Example 1.

[0038] Figure 6Graphs showing the charge / discharge capacities of lithium-ion batteries prepared in Example 1 and Comparative Example 1 at different current densities. DETAILED DESCRIPTION

[0039] In order to enable those skilled in the art to better understand and implement the technical solution of the present invention, the present invention is further described below with reference to specific embodiments and drawings.

[0040] In the description of the present invention, unless otherwise specified, all reagents used are commercially available and all methods used are conventional techniques in the art.

[0041] It should be noted that the full name of the metal-organic framework in English is Metal-Organic Framework, abbreviated as MOF in English. It is a porous material composed of inorganic metal vertices and organic ligands connected by coordination bonds. Due to its unique structure and properties, it has received widespread attention in the field of electrochemical energy storage. MOFs have an extremely high specific surface area, which is conducive to their full contact with other components and enhanced electrochemical performance. At the same time, the surface polarity of MOFs is adjustable, which can change the Lewis acid-base interaction in the mixed system, thereby potentially improving the overall electrochemical performance of the solid electrolyte. The rich pores of MOFs provide uniform dispersion sites and clear transmission paths for the migration of lithium ions, which is a significant advantage compared to traditional inorganic fillers.

[0042] The microporous properties and ordered channels of MOFs allow for more uniform deposition of lithium ions during cyclic charge and discharge, helping to form a stable interfacial layer and improving the battery's cycling stability. MOFs also possess high surface energy and strong adsorption capacity, enabling them to capture impurities and byproducts in the system and inhibit side reactions, which is crucial for improving battery safety and stability. Therefore, these properties of MOFs give them the potential to enhance electrochemical performance, cycling stability, and safety in solid-state electrolytes.

[0043] The present invention uses MOFs material as a rigid porous skeleton and a polymer matrix as a flexible phase. By introducing MOFs to modify the polymer matrix, the porous structure and open metal sites of the MOFs material can effectively regulate the uniform deposition of lithium ions and inhibit the formation of lithium dendrites, thereby improving the overall performance of the battery.

[0044] The present invention provides a method for preparing a MOFs-based solid electrolyte membrane, comprising the following steps:

[0045] Step 1: Disperse MOFs in a solvent, and after uniform dispersion, add a polymer matrix and lithium salt to obtain a precursor solution.

[0046] Preferably, the mass of the lithium salt is 10% to 40% of the mass of the polymer matrix.

[0047] Preferably, the mass of the MOFs is 1% to 10% of the mass of the polymer matrix.

[0048] It should be noted that the micropores of MOFs match the diameter of Li+ hydrated ions in lithium salts, selectively promoting Li+ transport through the "size screening effect" and serving as the main channel for rapid Li+ transport. At the same time, the imidazole ring on the surface of MOFs contains lone pairs of electrons, which react with ClO4 in lithium salts. - It forms a weak coordination effect, reduces the dissociation energy of lithium salt, and promotes the dissociation of lithium salt.

[0049] Preferably, the lithium salt is lithium perchlorate or lithium bis(trifluoromethanesulfonyl)imide.

[0050] The chain segments of the polymer matrix are adsorbed on the surface of MOFs through van der Waals forces, forming a "polymer brush" structure to prevent MOFs from agglomerating; at the same time, the strong polar CF bonds of the polymer matrix form dipole-ion interactions with Li+, promoting the dissociation of lithium salts and forming a "MOFs-polymer matrix-lithium salt" ternary composite interface.

[0051] Preferably, the polymer matrix is one of polyvinylidene fluoride-hexafluoropropylene, polyvinylidene fluoride, polyacrylonitrile, polyethylene oxide and polymethyl methacrylate. Compared to other polymer matrices, polyvinylidene fluoride-hexafluoropropylene has low crystallinity and low glass transition temperature, which allows it to maintain flexibility at room temperature and prevent brittle cracking of the electrolyte membrane. At the same time, polyvinylidene fluoride-hexafluoropropylene exhibits good electrochemical properties and flexibility, and can provide better ionic conductivity and mechanical stability. More preferably, the polymer matrix is polyvinylidene fluoride-hexafluoropropylene.

[0052] Preferably, the MOFs is one of ZIF-8, ZIF-67 and MOF-5.

[0053] Step 2: Add a photocurable resin to the precursor solution. Under the action of a photoinitiator, the monomers of the photocurable resin are polymerized by photocuring, and the chain segments of the polymer matrix are adsorbed on the surface of MOFs. The lithium salt is adsorbed on the surface of MOFs through electrostatic action, forming a MOFs-polymer matrix-lithium salt ternary composite interface, which serves as a stable Li+ transport network to obtain a MOF-based solid electrolyte membrane.

[0054] It should be noted that the photoinitiator generates free radicals under UV irradiation, triggering the polymerization of the monomers in the photocurable resin. Photocuring rapidly fixes the MOFs-polymer matrix-lithium salt composite interface, forming a stable Li+ transport network. The stress generated by the shrinkage of the photocurable resin induces phase separation between the polymer matrix and the MOFs, forming interconnected pores that enhance porosity and the connectivity of the Li+ migration pathway.

[0055] Preferably, the light-curable resin is ethoxylated trimethylolpropane triacrylate and polyurethane acrylate.

[0056] UV light excites the photoinitiator to produce free radicals, which attack the acrylate double bonds of ethoxylated trimethylolpropane triacrylate and polyurethane acrylate, triggering a chain growth reaction; the rapid cross-linking of ethoxylated trimethylolpropane triacrylate forms a rigid skeleton, and the slow polymerization of polyurethane acrylate fills the gaps to form an interpenetrating network, thereby enhancing the mechanical strength of the MOFs-based solid electrolyte membrane.

[0057] Furthermore, the volume of ethoxylated trimethylolpropane triacrylate shrinks during polymerization, generating stress at the interface between the polymer matrix and MOFs, inducing the formation of mesopores. The flexibility of the polyurethane acrylate polyurethane chains buffers the rigidity of ethoxylated trimethylolpropane triacrylate, preventing brittle cracking, while its hydrophobic groups inhibit water absorption by the electrolyte. The copolymerization of ethoxylated trimethylolpropane triacrylate and polyurethane acrylate forms a double network, which enhances interfacial bonding through hydrogen bonding.

[0058] It should be noted that the full English name of polyvinylidene fluoride-hexafluoropropylene is Polyvinylidene fluoride-hexafluoropropylene copolymer, abbreviated as PVDF-HFP; the full English name of polyacrylonitrile is, abbreviated as PAN; the full English name of N,N-dimethylformamide is N,N-Dimethylformamide, abbreviated as DMF; polyvinylidene fluoride-hexafluoropropylene, abbreviated as PVDF-HFP; the full English name of polyurethane acrylate is PolyurethaneAcrylate, abbreviated as PUA; the English name of ethoxylated trimethylolpropane triacrylate is trimethylolpropane ethoxylate triacrylate, abbreviated as ETPTA; 2-hydroxy-2-methyl-1-phenyl-1-propanone, abbreviated as HMPP; the full name of ZIF-8 is zeolite imidazolate framework material-8, which is a metal-organic framework material;

[0059] Example 1

[0060] This embodiment provides a method for preparing a MOFs-based solid electrolyte membrane, comprising the following steps:

[0061] Step 1: Prepare the precursor solution:

[0062] 80 mg of ZIF-8 was dispersed in 8 g of DMF and ultrasonicated for 30 min to completely disperse it to obtain a ZIF-8 solution.

[0063] 2 g of PVDF-HFP and 0.6 g of LiClO4 were added to the ZIF-8 solution in sequence, and stirred at 45°C for 4 h at a stirring speed of 450 r / min to obtain a precursor solution.

[0064] Step 2: Preparation of MOFs-based solid electrolyte membrane:

[0065] 0.8 g of ETPTA and 0.5 g of PUA were added to the precursor solution, and the mixture was stirred for 15 min. Then, 0.01 g of HMPP was added, and the mixture was stirred for 15 min. Finally, the mixture was ultrasonicated for 30 min to obtain a mixed solution.

[0066] The mixed solution was poured onto a polytetrafluoroethylene plate, coated with a 200 μm angle cutter, and placed in a UV light curing machine for light curing for 1 minute. After curing, it was placed in a vacuum environment at 60°C and dried for 90 minutes to obtain a MOFs-based solid electrolyte membrane.

[0067] Example 2

[0068] This embodiment provides a method for preparing a MOFs-based solid electrolyte membrane, comprising the following steps:

[0069] Step 1: Prepare the precursor solution:

[0070] 80 mg of ZIF-8 was dispersed in 8 g of DMF and ultrasonicated for 30 min to completely disperse it to obtain a ZIF-8 solution.

[0071] 1.5 g of PAN and 0.6 g of LiClO4 were added to the ZIF-8 solution in sequence, and the mixture was stirred at 45° C. for 4 h at a stirring speed of 450 r / min to obtain a precursor solution.

[0072] Step 2: Preparation of MOFs-based solid electrolyte membrane:

[0073] 0.6 g of ETPTA and 0.3 g of PUA were added to the precursor solution, and the mixture was stirred for 15 min. Then, 0.01 g of HMPP was added, and the mixture was stirred for 15 min. Finally, the mixture was ultrasonicated for 30 min to obtain a mixed solution.

[0074] The mixed solution was poured onto a polytetrafluoroethylene plate, coated with a 200 μm angle cutter, and placed in a UV light curing machine for light curing for 2 minutes. After curing, it was placed in a vacuum environment at 60°C and dried for 90 minutes to obtain a MOFs-based solid electrolyte membrane.

[0075] Comparative Example 1

[0076] This comparative example provides a method for preparing a polymer electrolyte membrane, comprising the following steps:

[0077] Step 1: Add 2 g of PVDF-HFP and 0.6 g of LiClO4 to DMF solvent, stir at 45°C for 4 h at a stirring speed of 450 r / min to obtain a precursor solution.

[0078] Step 2: Add 0.8 g of ETPTA and 0.5 g of PUA to the precursor solution and continue stirring for 15 min to obtain a mixed solution; pour the mixed solution onto a polytetrafluoroethylene plate, apply it with a 200 μm angle cutter, and dry it in a vacuum environment at 60°C for 90 min to obtain a polymer electrolyte membrane.

[0079] Application Example 1

[0080] This application embodiment provides a method for preparing a lithium-ion battery, comprising the following steps:

[0081] Preparation of positive electrode sheet:

[0082] Lithium iron phosphate, PVDF and conductive carbon were weighed in a mass ratio of 8:1:1, and the lithium iron phosphate, PVDF and conductive carbon were placed in DMF and mixed evenly to obtain a slurry; the slurry was placed on aluminum foil and dried in a vacuum drying oven at 60°C for 36 hours to obtain a positive electrode sheet; and the sheet was cut into discs with a diameter of 14 mm for later use.

[0083] Preparation of lithium-ion batteries:

[0084] The MOFs-based solid electrolyte membrane prepared in Example 1 was cut into discs with a diameter of 19 mm. In a glove box with an oxygen and water content of less than 0.1 ppm, the negative electrode lithium sheet, the diaphragm material, the MOFs-based solid electrolyte membrane prepared in Example 1 and the positive electrode sheet were assembled in sequence to prepare a lithium-ion battery.

[0085] Comparative Application Example 1

[0086] This application comparative example provides a method for preparing a lithium ion battery, comprising the following steps:

[0087] Preparation of positive electrode sheet:

[0088] Lithium iron phosphate, PVDF and conductive carbon were weighed in a mass ratio of 8:1:1, and the lithium iron phosphate, PVDF and conductive carbon were placed in DMF and mixed evenly to obtain a slurry; the slurry was placed on aluminum foil and dried in a vacuum drying oven at 60°C for 36 hours to obtain a positive electrode sheet; and the sheet was cut into discs with a diameter of 14 mm for later use.

[0089] Preparation of lithium-ion batteries:

[0090] The polymer electrolyte membrane prepared in Comparative Example 1 was cut into discs with a diameter of 19 mm. In a glove box with oxygen and water content lower than 0.1 ppm, the negative electrode lithium sheet, diaphragm material, polymer electrolyte membrane prepared in Comparative Example 1 and positive electrode sheet were assembled in sequence to prepare a lithium-ion battery.

[0091] Experimental test:

[0092] 1. SEM characterization.

[0093] like Figure 1 As shown, the surface of the MOFs-based solid electrolyte membrane prepared in Example 1 is uniform and has a porous structure.

[0094] 2. Electrochemical testing.

[0095] Electrochemical impedance spectroscopy was measured at an open circuit voltage of 0.1 Hz to 1 MHz with an amplitude of 10 mV, with the solid electrolyte membrane sandwiched between two smooth steel electrodes. The ionic conductivity of different electrolytes was calculated according to the formula:

[0096]

[0097] Where σ is the ionic conductivity; R is the impedance obtained by electrochemical impedance spectroscopy; L is the thickness of the solid electrolyte membrane, in cm; S is the effective area of the solid electrolyte membrane, in cm -2 .

[0098] The chronoamperometry method was used to measure the Li-Li symmetric cells assembled with different electrolytes. A 10mV polarization voltage was applied to the cell for 4000 seconds. The AC impedance spectra before and after polarization were recorded at a 10mV oscillating voltage with a frequency of 0.1Hz to 1MHz. The lithium ion transference number was calculated using the formula:

[0099]

[0100] Among them, t Li+ is the lithium ion migration number; I0 is the initial current; I S is the steady-state current, R0 is the electrolyte system before polarization; R S is the charge transfer resistance of the electrolyte system after polarization; ΔV is the oscillation voltage 10 mV.

[0101] The linear sweep voltammetry method was used to measure the voltage of the sample at a rate of 5mv in the voltage range of 2V to 6V. -1 The electrochemical window test of Li / solid electrolyte membrane / steel sheet battery was carried out at a scan rate of 100 nm.

[0102] like Figures 2 to 5 As shown in Figure 1, the ionic conductivity of the MOFs-based solid electrolyte membrane prepared in Example 1 is 1.17×10- 3 S / cm, the lithium ion transference number is 0.67, and the electrochemical window is 4.7 V. The ionic conductivity of the polymer electrolyte membrane prepared in Comparative Example 1 is 1.04×10 -4 S / cm, and the electrochemical window is 4.4 V. Experimental results show that the addition of ZIF-8 improves electrochemical properties such as ionic conductivity. This is attributed to the metal active sites of ZIF-8 providing hopping sites for lithium ion transport in the solid electrolyte, the effective capture ability of ZIF-8 for small molecules, and the strong interaction between ZIF-8 particles and polymer chains, which promotes the transport of lithium ions.

[0103] The present invention uses a Xinwei battery tester to perform electrochemical testing, and evaluates the battery's cycle stability, rate performance, and efficiency changes through charge and discharge curve analysis to evaluate the battery's performance.

[0104] In the rate test, the battery was tested at charge and discharge rates of 0.1C, 0.2C, 0.5C, 1C, and 2C, and the specific capacity of the battery at different rates was recorded. All tests were conducted at room temperature.

[0105] like Figure 6 As shown, the lithium-ion battery prepared using Example 1 has a specific capacity of 162 mAh / g at a charge-discharge rate of 0.1C and a specific capacity of 73 mAh / g at a charge-discharge rate of 2C, while the lithium-ion battery prepared using Comparative Example 1 has a specific capacity of 149 mAh / g at 0.1C and 37 mAh / g at 2C. This shows that the lithium-ion battery prepared using the MOFs-based solid electrolyte membrane of the present invention has a high discharge specific capacity.

[0106] Obviously, those skilled in the art may make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if such modifications and variations fall within the scope of the claims and their equivalents, the present invention is intended to encompass such modifications and variations. The above-described embodiments are merely preferred embodiments for the purpose of fully illustrating the present invention and are not intended to limit the scope of protection.

Claims

1. A method for preparing a MOFs-based solid electrolyte membrane, comprising the following steps: The MOFs are dispersed in a solvent, and after uniform dispersion, a polymer matrix and a lithium salt are added to obtain a precursor solution; A photocurable resin is added to the precursor solution. Under the action of a photoinitiator, the monomers of the photocurable resin are polymerized by photocuring, and the chain segments of the polymer matrix are adsorbed on the surface of MOFs. The lithium salt is adsorbed on the surface of MOFs through electrostatic interaction, forming a MOFs-polymer matrix-lithium salt ternary composite interface, which serves as a stable Li+ transport network to obtain a MOF-based solid electrolyte membrane. The MOFs are ZIF-8, ZIF-67 or MOF-5; The mass of the MOFs is 1% to 10% of the mass of the polymer matrix.

2. The method for preparing a MOFs-based solid electrolyte membrane according to claim 1, wherein: The mass of the lithium salt is 10% to 40% of the mass of the polymer matrix.

3. The method for preparing a MOFs-based solid electrolyte membrane according to claim 1, wherein: The usage ratio of the MOFs and the photocurable resin is 1-8:50-200.

4. The method for preparing a MOFs-based solid electrolyte membrane according to claim 1, wherein: The light curing conditions are as follows: the power of the UV light source is 3KW to 5KW, and the light curing time is 1 minute to 3 minutes.

5. The method for preparing a MOFs-based solid electrolyte membrane according to claim 1, wherein: The temperature for preparing the precursor solution is 40°C to 50°C.

6. The method for preparing a MOFs-based solid electrolyte membrane according to claim 1, wherein: The lithium salt is lithium perchlorate or lithium bis(trifluoromethanesulfonyl)imide; The polymer matrix is polyvinylidene fluoride-hexafluoropropylene, polyvinylidene fluoride, polyacrylonitrile, polyethylene oxide or polymethyl methacrylate.

7. The method for preparing a MOFs-based solid electrolyte membrane according to claim 1, wherein: The light-curable resin is one or more of ethoxylated trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, polyurethane acrylate, di(2-ethylhexyl) phthalate, dibasic fatty acid esters, and phthalate esters; The photoinitiator is 2-hydroxy-2-methyl-1-phenyl-1-propanone.

8. A MOFs-based solid electrolyte membrane, characterized in that: The MOFs-based solid electrolyte membrane is prepared by the preparation method of the MOFs-based solid electrolyte membrane according to any one of claims 1 to 7.

9. Use of the MOFs-based solid electrolyte membrane according to claim 8 as a solid electrolyte for lithium-ion batteries.

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