An amine-functionalized molecular sieve composite electrolyte membrane, a preparation method and application thereof

Abstract

The application discloses an amine functionalized molecular sieve composite electrolyte membrane and a preparation method and application thereof, and belongs to the technical field of battery materials, wherein the preparation method of the amine functionalized molecular sieve composite electrolyte membrane comprises the following steps: dispersing a polymer matrix and a metal salt in an organic solvent to obtain a mixed solution A; adding dried amine functionalized molecular sieve material into the mixed solution A to obtain a mixed solution B; performing dispersion treatment on the mixed solution B at 50-70 DEG C to form a continuous penetration network, and obtaining a composite solution; casting the composite solution into a film, naturally evaporating, and then performing vacuum drying to obtain the molecular sieve composite electrolyte membrane. The application realizes the synergistic improvement of the polymer electrolyte in ion conductivity, mechanical stability and interface stability by constructing a multistage metal ion conduction channel and an interface enhanced network, thereby effectively solving the problems of low conductivity, poor interface stability and insufficient mechanical properties of the traditional polymer electrolyte.

Description

Technical Field

[0001] This invention relates to the field of battery materials technology, specifically to an amine-functionalized molecular sieve composite electrolyte membrane, its preparation method, and its application. Background Technology

[0002] Lithium metal batteries and lithium-air batteries are widely considered key candidates for next-generation high-energy-density energy storage systems. Lithium metal batteries possess extremely high theoretical specific capacity and extremely low electrochemical potential. Lithium-air batteries, on the other hand, boast an even higher theoretical energy density, far exceeding any current lithium-ion battery system. These superior theoretical properties demonstrate their immense application potential in aerospace, high-end electric equipment, and extreme environment energy storage—fields with stringent requirements for weight and performance. However, these two battery systems still face a series of severe technical challenges in transitioning from laboratory applications to large-scale commercial use. The core bottleneck lies in electrolyte materials and the resulting interface problems. Currently, the widely studied liquid electrolyte system suffers from the following inherent defects: firstly, liquid electrolytes are flammable and volatile, and exhibit strong chemical incompatibility with lithium metal or lithium oxidation reaction products, leading to poor safety; secondly, liquid systems struggle to effectively suppress lithium dendrite penetration growth and interfacial side reactions, significantly reducing battery structural stability and cycle life.

[0003] To address the aforementioned issues, solid-state polymer electrolytes, due to their excellent flexibility, interfacial compatibility, and processability, are considered ideal alternative materials for improving the safety and stability of lithium-based batteries. However, traditional single polyether polymers (such as PEO) or fluoropolymers (such as PVDF) systems typically exhibit low ionic conductivity (<10) at room temperature. -5 S·cm -1 Problems such as insufficient mechanical strength and weak interfacial reactivity make it difficult to achieve stable operation under high-rate and long-cycle conditions. Especially in lithium-air batteries, the irreversible oxygen reduction products deposited at the electrode interface during discharge further aggravate the structural damage and functional degradation of the electrolyte, placing higher performance requirements on electrolyte materials.

[0004] To overcome the shortcomings of single polymers, researchers have developed composite electrolytes, which involve introducing inorganic fillers into a polymer matrix. These fillers improve the mechanical strength and ionic conductivity of the electrolyte to some extent. However, these traditional inorganic fillers typically have amorphous or randomly distributed pore structures, and their function is mostly passive enhancement. They have limited ability to promote lithium-ion transport and regulate interface stabilization mechanisms, and are particularly unable to solve core interface problems such as lithium dendrite and oxygen reduction product deposition.

[0005] In recent years, porous materials, especially molecular sieves with regular and ordered pore structures, have demonstrated unique advantages in composite electrolytes. Their regular one-dimensional or three-dimensional channels can serve as ideal lithium-ion transport channels, enabling rapid and directional ion migration. Although molecular sieve-polymer composite electrolytes hold great promise, current research is still in its early stages. How to precisely design the structure-function relationship between molecular sieve pore structure, surface properties, and polymer segments to construct interpenetrating network structures that combine ionic conductivity, mechanical stability, and interfacial stability remains a key scientific and technological challenge that urgently needs to be addressed in this field.

[0006] Therefore, developing a molecular sieve-polymer composite solid electrolyte material with tunable structure, controllable interface, and excellent conductivity has become a key technological path to promote high energy density, high safety, and long cycle life of lithium metal batteries and lithium-air batteries. Summary of the Invention

[0007] The purpose of this invention is to provide a method for preparing an amine-functionalized molecular sieve composite electrolyte membrane, so as to solve the problems mentioned in the background art.

[0008] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0009] A method for preparing an amine-functionalized molecular sieve composite electrolyte membrane includes the following steps:

[0010] The polymer matrix and metal salt are dispersed in an organic solvent to obtain mixture A;

[0011] Add dried amine-functionalized molecular sieve material to mixture A to obtain mixture B;

[0012] Disperse the mixture B at 50-70℃ to form a continuous permeation network and obtain a composite solution.

[0013] The composite solution was cast into a film, and after natural evaporation, it was dried under vacuum to obtain an amine-functionalized molecular sieve composite electrolyte membrane.

[0014] Furthermore, the mass ratio of the metal salt to the polymer matrix is ​​0.1:1 to 0.2:1.

[0015] Furthermore, the polymer matrix is ​​one or more of polyethylene oxide, polyvinylidene fluoride, and carboxymethyl cellulose.

[0016] Furthermore, the metal salt is a lithium salt.

[0017] Furthermore, the organic solvent is one or more of N-methylpyrrolidone and acetonitrile.

[0018] Furthermore, the amine-functionalized molecular sieve material is first vacuum dried at 170-190°C before being added to remove residual moisture from the pores.

[0019] Furthermore, the mass ratio of the amine-functionalized molecular sieve material to the polymer matrix is ​​0.5:1-1.2:1.

[0020] Furthermore, the amine-functionalized molecular sieve material is one or more of NH2-MCM-41, NH2-SBA-15, and NH2-KIT-6; NH2-MCM-41, NH2-SBA-15, and NH2-KIT-6 are prepared by adding MCM-41, SBA-15, and KIT-6 to a 10%-20% cationic functional reagent EPI-DMA solution, and then functionalizing them using ultrasound.

[0021] Another objective of this invention is to provide an amine-functionalized molecular sieve composite electrolyte membrane prepared by the above-described method.

[0022] Another objective of this invention is to provide an application of the above-mentioned amine-functionalized molecular sieve composite electrolyte membrane in the preparation of metal-ion batteries.

[0023] This invention provides a method for preparing an amine-functionalized molecular sieve composite electrolyte membrane. By introducing an amine-functionalized molecular sieve material with an ordered and regular pore structure into a polymer matrix, a multi-scale, highly interconnected ion migration network is constructed. This significantly improves the ionic conductivity and lithium-ion transference number of the polymer electrolyte, effectively alleviating interfacial instability and dendrite growth problems. The amine-functionalized molecular sieve composite electrolyte membrane prepared by this invention possesses flexibility, self-support, and structural stability, making it suitable for high-energy-density systems such as lithium metal batteries and lithium-air batteries. Batteries assembled with this membrane exhibit excellent rate performance and cycle stability, demonstrating promising application prospects and engineering potential. Attached Figure Description

[0024] Figure 1 This is a scanning electron microscope image of the amine-functionalized molecular sieve composite electrolyte membrane prepared in Example 1 of the present invention;

[0025] Figure 2 The AC impedance spectrum of the amine-functionalized molecular sieve composite electrolyte membrane prepared in Example 1 of this invention;

[0026] Figure 3 In the middle: a is the constant current polarization curve of the lithium symmetric battery assembled with the electrolyte membrane prepared in Example 3 of the present invention, and b is the electrochemical impedance of the lithium symmetric battery assembled with the electrolyte membrane prepared in Example 3 before and after polarization.

[0027] Figure 4This is a scanning electron microscope image of the amine-functionalized molecular sieve composite electrolyte membrane prepared in Example 2 of the present invention;

[0028] Figure 5 The AC impedance spectrum of the amine-functionalized molecular sieve composite electrolyte membrane prepared in Example 2 of this invention;

[0029] Figure 6 In the middle: a is the constant current polarization curve of the lithium symmetric battery assembled with the electrolyte membrane prepared in Example 3 of the present invention, and b is the electrochemical impedance of the lithium symmetric battery assembled with the electrolyte membrane prepared in Example 3 before and after polarization.

[0030] Figure 7 The AC impedance spectrum of the amine-functionalized molecular sieve composite electrolyte membrane prepared in Example 3 of this invention;

[0031] Figure 8 In the middle: a is the constant current polarization curve of the lithium symmetric battery assembled with the electrolyte membrane prepared in Example 3 of the present invention, and b is the electrochemical impedance of the lithium symmetric battery assembled with the electrolyte membrane prepared in Example 3 before and after polarization.

[0032] Figure 9 The solid-state symmetric cell assembled in Example 4 is at 0.1 mA·cm -2 Long-term cycling stability curves at current density; in the figure, a, b, and c are the long-term cycling stability curves of solid-state symmetric batteries assembled with amine-functionalized molecular sieve composite electrolyte membranes prepared in Examples 1-3, respectively.

[0033] Figure 10 The graph shows the charge-discharge cycle performance of the Li||NCM811 all-solid-state battery assembled in Example 5 at a rate of 0.2C.

[0034] Figure 11 The solid-state lithium-air battery assembled in Example 6 operates at 0.1 mA·cm⁻¹ -2 Cyclic stability plot at current density;

[0035] Figure 12 The graph shows the cycling performance of the PVDF electrolyte system without molecular sieves in Comparative Example 1 in a Li||NCM811 battery;

[0036] Figure 13 The graph shows the cycling performance of the non-amine-functionalized molecular sieve PVDF system electrolyte in Comparative Example 2 in a Li||NCM811 battery. Detailed Implementation

[0037] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0038] Amine-functionalized molecular sieve materials, due to their ordered and regular pore structure, high thermal stability, and good cycling stability, are widely used in gas and molecular trapping technologies. Introducing amine-functionalized molecular sieve materials with abundant active groups into polymer matrices can not only construct continuous lithium-ion migration channels at the microscale but also spatially confine large-sized anions, thereby significantly increasing the lithium-ion transference number and effectively alleviating problems such as ion aggregation and electric field concentration, thus improving overall ionic conductivity and interfacial stability. Furthermore, by combining natural polymers (such as cellulose) with highly polar polymers (such as PEO and PVDF) and synergistically constructing interpenetrating network structures with amine-functionalized molecular sieves, not only can the flexibility and mechanical strength of the polymer system be improved, but the interfacial compatibility between the polymer and the inorganic phase can also be significantly improved. This results in a uniform distribution of electric field and stress at the microscale, effectively suppressing lithium dendrite growth and irregular deposition of oxygen reduction products.

[0039] Specifically, in one embodiment of the present invention, a method for preparing an amine-functionalized molecular sieve composite electrolyte is provided, comprising the following steps:

[0040] S1. Disperse the polymer matrix and metal salt in an organic solvent to obtain mixture A;

[0041] S2. Add the dried amine-functionalized molecular sieve material to mixture A to obtain mixture B; wherein, the amine-functionalized molecular sieve material is first vacuum dried at 170-190℃ before being added to remove residual moisture in the pores.

[0042] S3. Disperse the mixture B at 50-70℃ to form a continuous permeation network and obtain a composite solution;

[0043] S4. Cast the composite solution into a film, controlling the film thickness between 100-200μm. After natural evaporation, vacuum dry at 50-70℃ to obtain amine-functionalized molecular sieve composite electrolyte.

[0044] In practical applications, the polymer matrix can be selected from, but is not limited to, one or more of polyethylene oxide (PEO), polyvinylidene fluoride (PVDF), and carboxymethyl cellulose (CMC); the metal salt can be selected from, but is not limited to, lithium salts, specifically lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) or lithium hexafluorophosphate; the organic solvent can be selected from, but is not limited to, one or more of N-methylpyrrolidone (NMP) and acetonitrile; and the amine-functionalized molecular sieve material can be selected from, but is not limited to, one or more of NH2-MCM-41, NH2-SBA-15, and NH2-KIT-6.

[0045] Specifically, NH2-MCM-41 was prepared by adding commercially available MCM-41 (CAS No. 12173-28-3) to 100 mL of a 10% cationic functional reagent EPI-DMA (epicochlorohydrin-dimethylamine copolymer, CAS No. 39660-17-8) solution and then functionalizing it using ultrasound; NH2-SBA-15 was prepared by adding commercially available SBA-15 (CAS No. 12173-28-3) to 100 mL of a 15% cationic functional reagent EPI-DMA solution and then functionalizing it using ultrasound; and NH2-KIT-6 was prepared by adding commercially available KIT-6 (CAS No. 12173-28-3) to 100 mL of a 20% cationic functional reagent EPI-DMA solution and then functionalizing it using ultrasound.

[0046] It should be noted that the content of the polymer matrix and the metal salt can be adjusted according to actual conditions, specifically optimized based on the selected polymer matrix type and target electrochemical performance. Furthermore, the content of the amine-functionalized molecular sieve material can be controlled within a certain range to balance the conductivity and mechanical properties of the molecular sieve composite electrolyte. Preferably, the mass ratio of the metal salt to the polymer matrix is ​​0.1:1-0.2:1; the mass ratio of the amine-functionalized molecular sieve material to the polymer matrix is ​​0.5:1-1.2:1.

[0047] It is worth noting that the covalent bonds formed between aminosilanes and polymers in amine-grafted molecular sieve materials enhance the stability of polymer chains. The abundant amino active groups enhance the hydrogen bonding / coordination with polymer chain segments, thereby improving the overall structural stability and interfacial ion flux.

[0048] In another embodiment of the present invention, an application of the amine-functionalized molecular sieve composite electrolyte membrane prepared above is also provided in the preparation of metal-ion batteries. Specifically, this amine-functionalized molecular sieve composite electrolyte membrane can be applied to high-safety, long-life electrochemical energy storage systems such as lithium metal and lithium-air batteries, exhibiting excellent room-temperature conductivity, processability, and structural stability.

[0049] In this embodiment of the invention, the amine-functionalized molecular sieve composite electrolyte membrane prepared above possesses excellent flexibility, self-support, and structural density, effectively adapting to advanced battery structure designs such as stacked and highly integrated designs. It is particularly suitable for metal anode energy storage systems with high safety requirements and long cycle life. This amine-functionalized molecular sieve composite electrolyte membrane maintains stable mechanical support and ion conductivity at room temperature, and exhibits excellent processing characteristics such as foldability and cutability, meeting the morphological adaptability and mechanical stability requirements of practical applications. Furthermore, the preparation method provided in this invention is mild, requiring no high-temperature sintering or complex post-processing steps, thus avoiding the problems of polymer chain structure damage or molecular sieve channel collapse. At the same time, it retains the confinement effect and directional control capability of the amine-functionalized molecular sieve structure on monomer / polymer chain segments, exhibiting excellent material adaptability and versatility. It is suitable for combinations of various polymer systems (such as PEO, PVDF, cellulose, etc.) and various types of amine-functionalized molecular sieves (such as NH2-MCM-41, NH2-SBA-15, NH2-KIT-6, etc.), and can flexibly adjust the composite ratio, film thickness, and pore structure to achieve synergistic optimization of mechanical properties, ion migration ability, and interface stability, showing good potential for large-scale preparation and industrial application prospects.

[0050] Specifically, the amine-functionalized molecular sieve material added in this embodiment of the invention not only serves as an inorganic framework to enhance the mechanical strength of the membrane, but also guides the rapid and directional migration of metal ions along ordered channels at the microstructural level, significantly increasing the metal ion transference number and suppressing dendrite growth caused by electric field concentration and ion accumulation. The amine-functionalized molecular sieve composite electrolyte prepared in this embodiment of the invention significantly improves the spatial order of polymer segments and the continuity of ion channels, enhancing the flexibility and self-support of the material at the macroscopic scale. Furthermore, this embodiment of the invention can achieve dual regulation and optimization of the mechanical properties (such as tensile strength, Young's modulus, and ductility) and electrochemical properties (such as room temperature conductivity, lithium ion transference number, and electrochemical stability window) of the electrolyte material by systematically controlling the type, addition ratio, polymer type, and metal salt concentration of the amine-functionalized molecular sieve material. This system exhibits excellent interfacial affinity and cycle stability in metal-ion batteries, effectively mitigating problems such as dendrite growth and interfacial contact failure. In lithium-air batteries, it also demonstrates good ion permeability and gas isolation capabilities, supporting high-energy-density discharge platforms and delaying the phenomenon of product blockage of electrode channels. Therefore, the amine-functionalized molecular sieve composite electrolyte membrane provided in this invention not only possesses a highly ordered microstructure, efficient metal-ion conduction channels, and good interfacial compatibility, but also exhibits excellent mechanical flexibility, environmental stability, and processing adaptability. It is suitable for high-energy, high-safety, and high-stability next-generation lithium metal batteries and solid-state / quasi-solid-state lithium-air batteries, demonstrating broad application prospects and promotional value.

[0051] The following embodiments are some specific implementation examples of the present invention in practical applications, but are not limited thereto.

[0052] Example 1: This example provides a method for preparing an amine-functionalized molecular sieve composite electrolyte membrane, including the following steps:

[0053] S1. Weigh 1g of PVDF and 0.12g of lithium salt LiTFSI and dissolve them in 20mL of NMP. Stir magnetically at room temperature to form a homogeneous viscous solution, and obtain mixture A.

[0054] S2. Add 1g of amine-functionalized molecular sieve material NH2-MCM-41 (specific surface area >500m²) that has been vacuum dried at 180℃ to the above mixture A. 2 ·g -1 ), to obtain mixture B;

[0055] S3. The above mixture B is magnetically stirred and dispersed at 70°C for 16 hours to ensure that the molecular sieve material is fully and uniformly dispersed in the polymer / lithium salt system to form a continuous permeation network and obtain a composite solution.

[0056] S4. The above composite solution is slowly cast into a polytetrafluoroethylene mold to form a film, and the film thickness is controlled between 100-200μm. After most of the organic solvent is naturally evaporated at room temperature, it is then vacuum dried at 60℃ for 24h to ensure that the organic solvent is completely evaporated. After peeling, the amine functionalized molecular sieve composite electrolyte membrane is obtained, which is denoted as NH2-MCM-41 molecular sieve composite PVDF electrolyte membrane. The membrane is cut into 16mm round pieces for subsequent assembly.

[0057] Example 2: This example provides a method for preparing an amine-functionalized molecular sieve composite electrolyte, including the following steps:

[0058] S1. Weigh 1g of PEO (molecular weight 600000) and 0.125g of lithium salt LiTFSI and dissolve them in 20mL of anhydrous acetonitrile. Stir magnetically at room temperature to form a uniform and transparent solution, and obtain mixture A.

[0059] S2. Add 1g of amine-functionalized molecular sieve material NH2-SBA-15, which has been vacuum dried at 180℃, to the above mixture A to obtain mixture B.

[0060] S3. The above mixture B is magnetically stirred and dispersed at 60°C for 16 hours to ensure that the amine functionalized molecular sieve material is fully and uniformly dispersed in the polymer / lithium salt system to form a continuous permeation network and obtain a composite solution.

[0061] S4. The above composite solution is slowly cast into a polytetrafluoroethylene mold to form a film, and the film thickness is controlled between 100-200μm. After most of the organic solvent is naturally evaporated at room temperature, it is vacuum dried at 60℃ for 12h to ensure that the organic solvent is completely evaporated. After peeling, the amine functionalized molecular sieve composite electrolyte membrane is obtained, which is denoted as NH2-SBA-15 molecular sieve composite PEO electrolyte membrane. The membrane is cut into 16mm round pieces for subsequent assembly.

[0062] Example 3: This example provides a method for preparing an amine-functionalized molecular sieve composite electrolyte, comprising the following steps:

[0063] S1. Weigh 0.8g of CMC and 0.1g of lithium salt LiTFSI and dissolve them in 20mL of NMP. Stir magnetically at room temperature to form a homogeneous viscous solution, and obtain mixture A.

[0064] S2. Add 0.5g of amine-functionalized molecular sieve material NH2-KIT-6, which has been vacuum dried at 170℃, to the above mixture A to obtain mixture B;

[0065] S3. The above mixture B is magnetically stirred and dispersed at 50°C for 12 hours to ensure that the amine functionalized molecular sieve material is fully and uniformly dispersed in the polymer / lithium salt system to form a continuous permeation network and obtain a composite solution.

[0066] S4. The above composite solution is slowly cast into a polytetrafluoroethylene mold to form a film, and the film thickness is controlled between 100-200μm. After most of the organic solvent is naturally evaporated at room temperature, it is vacuum dried at 50℃ for 12h to ensure that the organic solvent is completely evaporated. After peeling, the amine functionalized molecular sieve composite electrolyte membrane is obtained, which is denoted as NH2-KIT-6 molecular sieve composite cellulose electrolyte membrane.

[0067] Example 4: This example provides a method for preparing a solid-state lithium symmetric battery, including the following steps: Two high-purity lithium sheets pre-cut to a diameter of 16 mm are used as symmetric electrodes and placed inside the positive and negative electrode shells of a 2032 coin cell, respectively. An amine-functionalized molecular sieve composite electrolyte membrane prepared in Examples 1-3 is sandwiched between them. The battery assembly process is completed in a glove box filled with high-purity argon gas (O2 and H2O contents both below 0.01 ppm) to prevent metallic lithium from reacting with air or moisture, ensuring interface stability and repeatability of battery performance. Subsequently, the positive electrode shell is placed over the negative electrode shell, and a pressure of 50 kg·cm⁻¹ is applied in a battery packaging machine. -2 Solid-state lithium symmetric batteries were fabricated by encapsulation under pressure, and the battery specification was CR2032.

[0068] Example 5: This example provides a method for preparing an all-solid-state Li||NCM811 battery, including the following steps: Weigh 0.8g NCM811, 0.1g PVDF and 0.1g SuperP, grind them, add 2.4mL NMP and stir for 4h to form a slurry, coat it on aluminum foil, and vacuum dry at 120℃ for 2h to form a positive electrode sheet with a loading of approximately 1.2mg·cm³. -2 In an argon-filled glove box, lithium foil (450 μm, φ 14 mm), amine-functionalized molecular sieve composite electrolyte membranes prepared in Examples 1-3, and positive electrode sheets (φ 12 mm) were sequentially stacked into a CR2032 battery case, fitted with gaskets and springs, and sealed under 700 kg pressure to obtain an all-solid-state Li||NCM811 battery.

[0069] Example 6: This example provides a method for preparing a solid-state lithium-air battery, including the following steps: In a glove box, the negative lithium sheet, the amine-functionalized molecular sieve composite electrolyte membrane prepared in Examples 1-3, and the carbon nanotube positive electrode are sequentially placed on a 2025 negative electrode shell. Finally, the perforated 2025 positive electrode shell is covered and assembled. The battery is placed on a battery packaging machine and subjected to a pressure of 50 kg·cm⁻¹. -2 Encapsulated under pressure, a solid-state lithium-air battery is obtained after encapsulation, with a battery specification of 2025.

[0070] Comparative Example 1: This comparative example provides a sieve-free PVDF system electrolyte and its assembled lithium metal battery, the preparation method of which includes the following steps:

[0071] (1) Weigh 1.0g of PVDF and 0.125g of lithium salt LiTFSI, add them to 20mL of NMP, and stir magnetically for 12 hours at room temperature to form a uniform and transparent polymer-lithium salt solution.

[0072] (2) The polymer-lithium salt solution obtained above was poured into a polytetrafluoroethylene mold to form a film. After evaporating naturally at room temperature for 24 hours, it was transferred to a vacuum box at 60°C to dry for 12 hours to obtain a peelable PVDF system electrolyte membrane without molecular sieves.

[0073] (3) The obtained electrolyte membrane was cut into a circular piece with a diameter of 16 mm, and assembled with the lithium negative electrode and the NCM811 positive electrode prepared in Example 4 in an argon glove box to form a CR2032 type all-solid-state battery. The battery was then encapsulated under a pressure of 700 kg to obtain an all-solid-state Li||NCM811 battery.

[0074] Comparative Example 2: This comparative example provides an electrolyte based on a non-amine-functionalized molecular sieve PVDF system and its assembled lithium metal battery. The preparation method includes the following steps:

[0075] (1) Weigh 1.0g of PVDF and 0.125g of lithium salt LiTFSI and MCM-41 molecular sieve, add them to 20mL of NMP, and stir magnetically for 12 hours at room temperature to form a homogeneous polymer-lithium salt solution.

[0076] (2) The polymer-lithium salt solution obtained above was poured into a polytetrafluoroethylene mold to form a film. After evaporating naturally at room temperature for 48 hours, it was transferred to a vacuum oven at 60°C and dried for 12 hours to obtain a peelable non-amine functionalized molecular sieve PVDF system electrolyte membrane.

[0077] (3) The obtained electrolyte membrane was cut into a circular piece with a diameter of 16 mm, and assembled with the lithium negative electrode and the NCM811 positive electrode prepared in Example 5 in an argon glove box to form a CR2032 type all-solid-state battery. The battery was then encapsulated under a pressure of 700 kg to obtain an all-solid-state Li||NCM811 battery.

[0078] Performance Testing: 1. The NH2-MCM-41 molecular sieve composite PVDF electrolyte membrane prepared in Example 1 was characterized by scanning electron microscopy, and the results are as follows: Figure 1 As shown, this demonstrates the uniformity and density of the electrolyte membrane. The conductivity of the NH2-MCM-41 molecular sieve composite PVDF electrolyte membrane prepared in Example 1 was tested. Specifically, the electrolyte membrane sample was sandwiched between two stainless steel sheets to test the ionic conductivity, which was measured to be 0.60 mS·cm. -1 , specifically Figure 2 As shown; the NH2-MCM-41 molecular sieve composite PVDF electrolyte membrane prepared in Example 1 was assembled into a lithium metal symmetric battery, and the lithium ion transference number was tested, yielding a lithium ion transference number of 0.78, as detailed below. Figure 3 As shown.

[0079] II. The NH2-SBA-15 molecular sieve composite PEO electrolyte membrane prepared in Example 2 was characterized by scanning electron microscopy, and the results are as follows: Figure 4 As shown, the conductivity performance of the NH2-SBA-15 molecular sieve composite PEO electrolyte membrane prepared in Example 2 was tested. Specifically, electrolyte membrane samples with a diameter of 16 mm were cut using a punching machine. The electrolyte membrane samples were sandwiched between two stainless steel sheets for ionic conductivity testing, and the measured ionic conductivity was 0.25 mS·cm. -1 , specifically Figure 5 As shown; the NH2-SBA-15 molecular sieve composite PEO electrolyte membrane prepared in Example 2 was assembled into a lithium metal symmetric battery, and the lithium ion transference number was tested, yielding a lithium ion transference number of 0.7, as detailed below. Figure 6 As shown.

[0080] 3. The ionic conductivity of the NH2-KIT-6 molecular sieve composite cellulose electrolyte membrane prepared in Example 3 was tested, and the measured ionic conductivity was 0.62 mS·cm. -1 , specifically Figure 7 As shown; the NH2-KIT-6 molecular sieve composite cellulose electrolyte membrane prepared in Example 2 was assembled into a lithium metal symmetric battery, and the lithium ion transference number was tested, yielding a lithium ion transference number of 0.75, as detailed below. Figure 8 As shown.

[0081] IV. The lithium symmetric battery prepared in Example 4 was tested at 0.1 mA·cm⁻¹. -2 It can be stably cycled for 2000 hours at a current density, specifically as follows: Figure 9 As shown.

[0082] V. The solid-state lithium metal battery prepared in Example 5 was tested and found to be capable of 200, 150, and 200 cycles at a current density of 0.2C. (Specific details are as follows...) Figure 10 As shown, this indicates that the solid-state lithium metal battery has good electrochemical performance.

[0083] V. The solid-state lithium-air battery prepared in Example 6 was tested at 0.1 mA·cm⁻¹. -2 It can cycle 200, 150, and 200 times at current densities, specifically as follows: Figure 11 As shown, this indicates that the solid-state lithium-air battery has good electrochemical performance.

[0084] VI. The Li||NCM811 battery assembled with the PVDF electrolyte system without molecular sieves in Comparative Example 1 was subjected to cycle performance testing, and the results are as follows: Figure 12 As shown, a performance comparison was made with Example 1: the battery had a normal initial capacity, but after 20 cycles, the polarization increased sharply, and the performance was significantly worse than that of Example 1.

[0085] VII. The Li||NCM811 battery assembled with the electrolyte of the non-amine-functionalized MCM-41 molecular sieve composite PVDF system in Comparative Example 2 was subjected to cycle performance testing, and the results are as follows: Figure 13 As shown, a performance comparison was made with Example 2: the battery had a normal initial capacity, but after 50 cycles, the polarization increased sharply, and the performance was significantly worse than that of Example 2.

[0086] In summary, the embodiments of this invention introduce amine-functionalized molecular sieve materials with ordered and regular pores into a polymer system to construct multi-scale coupled ion migration channels, achieving efficient conduction and controllable transport of lithium ions under room temperature conditions. The amine-functionalized molecular sieve framework in the material system mentioned in these embodiments is rich in surface active sites, enabling selective adsorption of anions and reducing their migration ability in the system, thereby improving cation migration efficiency and forming a lithium-ion-dominated unipolar migration process. This ion screening effect not only increases the overall migration number but also suppresses polarization accumulation and electric field inhomogeneity, enhancing interface stability. Thanks to the synergistic effect of the above structure and mechanism, the amine-functionalized molecular sieve composite electrolyte membrane prepared in these embodiments exhibits excellent deposition uniformity at the lithium metal anode interface, effectively delaying dendrite penetration and short-circuit risks. Furthermore, this electrolyte system also exhibits good adaptability in lithium-air batteries; its flexible framework structure helps buffer volume changes caused by discharge products, while possessing good gas barrier properties and electrolyte / electrode interface coupling characteristics, thereby improving the battery's reaction reversibility and cycle stability. In summary, the amine-functionalized molecular sieve composite electrolyte material constructed in the embodiments of the present invention has high ionic conductivity, excellent interfacial compatibility and stable structural characteristics, and is suitable for novel high-energy electrochemical energy storage systems such as lithium metal batteries and lithium-air batteries, and has good practical value and promotion prospects.

[0087] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification.

Claims

1. A method for preparing an amine-functionalized molecular sieve composite electrolyte membrane, characterized in that, Includes the following steps: The polymer matrix and metal salt are dispersed in an organic solvent to obtain mixture A; Add dried amine-functionalized molecular sieve material to mixture A to obtain mixture B; Disperse the mixture B at 50-70℃ to form a continuous permeation network and obtain a composite solution. The composite solution was cast into a film, and after natural evaporation, it was dried under vacuum to obtain an amine-functionalized molecular sieve composite electrolyte membrane. The amine-functionalized molecular sieve material is one or more of NH2-MCM-41, NH2-SBA-15, and NH2-KIT-6; NH2-MCM-41, NH2-SBA-15, and NH2-KIT-6 are prepared by adding MCM-41, SBA-15, and KIT-6 to a 10%-20% cationic functional reagent EPI-DMA solution, and then functionalizing them using ultrasound.

2. The method for preparing the amine-functionalized molecular sieve composite electrolyte membrane according to claim 1, characterized in that, The mass ratio of the metal salt to the polymer matrix is ​​0.1:1 to 0.2:

1.

3. The method for preparing the amine-functionalized molecular sieve composite electrolyte membrane according to claim 1 or 2, characterized in that, The polymer matrix is ​​one or more of polyethylene oxide, polyvinylidene fluoride, and carboxymethyl cellulose.

4. The method for preparing the amine-functionalized molecular sieve composite electrolyte membrane according to claim 1 or 2, characterized in that, The metal salt is a lithium salt.

5. The method for preparing the molecular sieve composite electrolyte membrane according to claim 1, characterized in that, The organic solvent is one or more of N-methylpyrrolidone and acetonitrile.

6. The method for preparing the amine-functionalized molecular sieve composite electrolyte membrane according to claim 1, characterized in that, The molecular sieve material is first vacuum dried at 170-190°C before being added to remove residual moisture from the pores.

7. The method for preparing the amine-functionalized molecular sieve composite electrolyte membrane according to claim 1, characterized in that, The mass ratio of the molecular sieve material to the polymer matrix is ​​0.5:1 to 1.2:

1.

8. An amine-functionalized molecular sieve composite electrolyte membrane prepared by any one of the preparation methods described in claims 1-7.

9. The application of the amine-functionalized molecular sieve composite electrolyte membrane as described in claim 8 in the preparation of metal-ion batteries.

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