Solid-state battery electrolyte material, preparation method thereof and solid-state lithium ion battery

Abstract

The invention provides a solid-state battery electrolyte material, a preparation method thereof and a solid-state lithium ion battery. The preparation method comprises the following steps: S1, carrying out first reaction on a first raw material comprising an organic ligand, zircon salt, a first acid solution and a first organic solvent to obtain a metal organic framework material; and step S2, carrying out a second reaction on a second raw material comprising dimethyl 2, 6-dipicolinate and a metal organic framework material to obtain the solid-state battery electrolyte material. The solid-state battery electrolyte material obtained by adopting the preparation method disclosed by the invention has good mechanical properties, a wider electrochemical window and higher ionic conductivity, so that the initial efficiency, the capacity and the cycle performance of the battery are improved, and the internal resistance of the battery is reduced at the same time.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more specifically, to a solid-state battery electrolyte material and its preparation method, and a solid-state lithium-ion battery. Background Technology

[0002] Lithium-ion batteries mainly consist of four parts: positive electrode material, negative electrode material, electrolyte, and separator. The electrolyte plays a crucial role in transporting lithium ions and conducting internal current. The organic solvents in liquid electrolytes are flammable, highly corrosive, and cannot solve the problem of lithium dendrite formation, posing a risk of thermal runaway. Solid-state lithium metal batteries (SSLMBs) replace the volatile organic liquid electrolytes in traditional lithium-ion batteries with solid electrolytes, effectively improving battery energy density and safety. Meanwhile, solid polymer electrolytes (SPEs) have attracted considerable attention due to their advantages such as low cost, flexibility, scalability, lightweight design, and good interfacial compatibility with electrodes. However, the insufficient lithium-ion conductivity of current solid polymer electrolytes limits their application and development. Summary of the Invention

[0003] The main objective of this invention is to provide a solid-state battery electrolyte material and its preparation method, as well as a solid-state lithium-ion battery, to solve the problem of low ionic conductivity in existing solid-state electrolytes.

[0004] To achieve the above objectives, according to one aspect of the present invention, a method for preparing a solid-state battery electrolyte material is provided, the method comprising: step S1, subjecting a first raw material comprising an organic ligand, a zirconium salt, a first acid solution and a first organic solvent to a first reaction to obtain a metal-organic framework material; and step S2, subjecting a second raw material comprising dimethyl 2,6-pyridine dicarboxylate and the metal-organic framework material to a second reaction to obtain a solid-state battery electrolyte material.

[0005] The preparation method of this application combines 2,6-pyridine dicarboxylic acid dimethyl ester with a metal-organic framework material, which can serve as an external framework and a composite solid electrolyte host. The resulting solid battery electrolyte material has good mechanical properties, a wide electrochemical window, and high ionic conductivity, thereby improving the battery's initial efficiency, capacity, and cycle performance, while reducing the battery's internal resistance.

[0006] Furthermore, step S1 above also includes: mixing the first raw material with ultrasound to obtain the mixed first raw material; subjecting the first mixed raw material to a first reaction to obtain a first product; subjecting the first product to solid-liquid separation and first drying in sequence to obtain a metal-organic framework material; wherein the temperature of the first drying is 100-160°C and the time of the first drying is 24-60h.

[0007] Ultrasonic dispersion is preferred, as it facilitates thorough mixing of the first raw material, thereby aiding in the subsequent first reaction. After solid-liquid separation, washing with N,N-dimethylformamide (DMF) and ethanol is performed, with the first drying temperature and time preferably within the aforementioned ranges to facilitate solvent removal.

[0008] Furthermore, in step S1 above, the temperature of the first reaction is 130–150°C, and the time of the first reaction is 48–72 h.

[0009] Preferably controlling the temperature and time of the first reaction within the above-mentioned range helps to improve the efficiency of the first reaction, thereby increasing the yield of the metal-organic framework material.

[0010] Further, in step S1 above, the organic ligand is selected from 2-aminoterephthalic acid, 2-vinylterephthalic acid, terephthalic acid, 2,5-dihydroxyterephthalic acid, 2-hydroxyterephthalic acid, monosodium 2-sulfonic acid terephthalic acid, p-mercaptoterephthalic acid, 2-methyl-1,4-phthalic acid, 1,4-naphthalenedicarboxylic acid, 2,2'-bipyridine-5,5'-dicarboxylic acid, trimesic acid, 4,4-azopyridine, 1,2-di(4-pyridyl)ethylene, 5,10,15,20-tetra-... (4-Aminophenyl)porphyrin, imidazophenylporphyrin, tetra(4-fluorophenyl)porphyrin, and meso-tetra(4-carboxyphenyl)porphyrin; and / or, the zirconium salt is selected from any one or more of zirconium tetrachloride, zirconium sulfate, and zirconium nitrate; and / or, the first acid solution is selected from any one or more of hydrochloric acid, sulfuric acid, and nitric acid, and the molar concentration of the first acid solution is 6 to 12 mol / L; the first organic solvent is selected from any one or more of N,N-dimethylformamide, N-methylpyrrolidone, and dimethyl sulfoxide.

[0011] The preferred organic ligands, zirconium salts, organic solvents, and the type and molar concentration of the first acid solution are within the above ranges, which facilitates the reaction between the zirconium salt and the organic ligands, thereby obtaining a structurally stable metal-organic framework material.

[0012] Furthermore, in step S1 above, the molar ratio of the organic ligand to the zirconium salt is 1:0.5 to 10.

[0013] Preferring the molar ratio of organic ligands to zirconium salt within the above range helps to promote the integrity and stability of the framework structure, regulate the pore size and distribution of the framework during growth, and obtain metal-organic framework materials with sufficient porosity and structural stability, thereby improving the lithium-ion transport efficiency.

[0014] Further, step S2 above also includes the following pre-preparation step of dimethyl 2,6-pyridinedicarboxylate: esterifying a raw material comprising 2,6-pyridinedicarboxylic acid, a second acid solution, and a second organic solvent to obtain a second product; subjecting the second product to solid-liquid separation and subsequent drying to obtain dimethyl 2,6-pyridinedicarboxylate; wherein the molar ratio of 2,6-pyridinedicarboxylic acid to the volume of the second acid solution is 3–10:1 mol / mL, the second acid solution is concentrated sulfuric acid with a mass fraction ≥70%, and the second organic solvent is N,N-dimethylformamide; the esterification reaction temperature is 90–140°C, and the esterification reaction time is 24–60 h; the second drying temperature is 100–160°C, and the second drying time is 24–60 h.

[0015] Furthermore, step S2 above also includes: mixing 2,6-pyridine dicarboxylic acid dimethyl ester and a third organic solvent to obtain a mixture; subjecting the mixture and the metal-organic framework material to a second reaction, solid-liquid separation, and a third drying process in sequence to obtain a solid-state battery electrolyte material; wherein the third organic solvent is selected from any one or more of N,N-dimethylformamide, N-methylpyrrolidone, and dimethyl sulfoxide; the temperature of the third drying is 100–130°C, and the time of the third drying is 24–60 h.

[0016] The preparation of dimethyl 2,6-pyridinedicarboxylate using the above method helps to improve the yield and quality of dimethyl 2,6-pyridinedicarboxylate.

[0017] Furthermore, the temperature of the second reaction is 90–140 °C, and the reaction time is 24–60 h; and / or, the molar ratio of 2,6-pyridinedicarboxylic acid dimethyl ester to the metal-organic framework material is 1–6:1–15.

[0018] Preferably, the second reaction is carried out by stirring at the temperature described above. This helps to uniformly disperse 2,6-pyridinedicarboxylate dimethyl ester in the metal-organic framework material, promoting a full reaction between the two. Preferably, the molar ratio of 2,6-pyridinedicarboxylate dimethyl ester to the metal-organic framework material is within the above-mentioned range. This not only helps to enhance the thermal and chemical stability of the composite material but also regulates the structure and chemical environment of the metal-organic framework material channels, thereby improving the ionic conductivity of the solid-state battery electrolyte material, and ultimately improving the battery's cycle performance, energy density, and safety.

[0019] According to another aspect of the present invention, a solid-state battery electrolyte material is provided, which is prepared by the preparation method described above.

[0020] The solid-state battery electrolyte material prepared by the above method has high ionic conductivity, which can reduce energy loss during charging and discharging and improve the overall energy efficiency of the battery.

[0021] Preferably, the ionic conductivity of the solid-state battery electrolyte material is within the above-mentioned range, which helps to mitigate electrode material damage during charge-discharge cycles, reduce lithium dendrite formation, and thus extend the battery's lifespan.

[0022] According to another aspect of the present invention, a solid-state lithium-ion battery is provided, comprising a solid electrolyte material, wherein the solid electrolyte material is the solid-state battery electrolyte material described above.

[0023] Solid-state lithium-ion batteries, including the aforementioned solid-state battery electrolyte materials, have high energy density, cycle performance, and safety.

[0024] By applying the technical solution of this invention, the introduction of metal-organic framework (MOF) materials into the solid-state battery electrolyte material of this application can promote the Li + The migration of these molecules effectively improves the ionic conductivity of solid-state battery electrolyte materials, thereby enhancing the battery's cycle performance. On one hand, metal-organic framework materials enable the highly crystallized 2,6-pyridinedicarboxylic acid dimethyl ester entangled in traditional solid polymer electrolytes (SPEs) at room temperature (25–30 °C), thus reducing the polymer's crystallinity and promoting Li... + Migration; on the other hand, the active metal sites (OMS) in the metal-organic framework material channels can capture lithium salt anions, promote lithium salt dissociation, and make Li the dominant charge carrier in the channel. + Meanwhile, the low-barrier channels within metal-organic framework materials can further promote Li + Migration effectively improves the ionic conductivity of solid-state battery electrolyte materials. Using MOFs alone as electrolyte materials suffers from low ionic conductivity, low ion transport number, narrow electrochemical stability window, and poor interfacial contact. However, the preparation method described in this application combines dimethyl 2,6-pyridine dicarboxylate with a metal-organic framework, which serves as both the external framework and the main body of the composite solid-state electrolyte. The resulting solid-state battery electrolyte material (the modified composite solid-state electrolyte) exhibits excellent mechanical properties, a wide electrochemical window, and high ionic conductivity, thereby improving battery initial efficiency, capacity, and cycle performance while reducing internal resistance. Furthermore, the preparation method used in this application employs economical reagents and a relatively mild preparation process, reducing the use of harmful solvents. Detailed Implementation

[0025] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the embodiments.

[0026] As analyzed in the background section of this application, solid electrolytes in the prior art have the problem of low ionic conductivity. In order to solve the above problem, this application provides a solid battery electrolyte material and its preparation method, as well as a solid lithium-ion battery.

[0027] In a typical embodiment of this application, a method for preparing a solid-state battery electrolyte material is provided. The method includes: step S1, subjecting a first raw material comprising an organic ligand, a zirconium salt, a first acid solution, and a first organic solvent to a first reaction to obtain a metal-organic framework material; and step S2, subjecting a second raw material comprising dimethyl 2,6-pyridine dicarboxylate and the metal-organic framework material to a second reaction to obtain a solid-state battery electrolyte material.

[0028] The solid-state battery electrolyte material of this application incorporates a metal-organic framework (MOF) to promote Li + The migration of these molecules effectively improves the ionic conductivity of solid-state battery electrolyte materials, thereby enhancing the battery's cycle performance. On one hand, metal-organic framework materials enable the highly crystallized 2,6-pyridinedicarboxylic acid dimethyl ester entangled in traditional solid polymer electrolytes (SPEs) at room temperature (25–30 °C), thus reducing the polymer's crystallinity and promoting Li... + Migration; on the other hand, the active metal sites (OMS) in the metal-organic framework material channels can capture lithium salt anions, promote lithium salt dissociation, and make Li the dominant charge carrier in the channel. + Meanwhile, the low-barrier channels within metal-organic framework materials can further promote Li + Migration effectively improves the ionic conductivity of solid-state battery electrolyte materials. Using MOFs alone as electrolyte materials suffers from low ionic conductivity, low ion transport number, narrow electrochemical stability window, and poor interfacial contact. However, the preparation method described in this application combines dimethyl 2,6-pyridine dicarboxylate with a metal-organic framework, which serves as both the external framework and the main body of the composite solid-state electrolyte. The resulting solid-state battery electrolyte material (the modified composite solid-state electrolyte) exhibits excellent mechanical properties, a wide electrochemical window, and high ionic conductivity, thereby improving battery initial efficiency, capacity, and cycle performance while reducing internal resistance. Furthermore, the preparation method used in this application employs economical reagents and a relatively mild preparation process, reducing the use of harmful solvents.

[0029] In one embodiment of this application, step S1 further includes: mixing the first raw material with ultrasound to obtain a mixed first raw material; subjecting the first mixed raw material to a first reaction to obtain a first product; subjecting the first product to solid-liquid separation and a first drying to obtain a metal-organic framework material; wherein the temperature of the first drying is 100-160°C and the time of the first drying is 24-60h.

[0030] Ultrasonic dispersion is preferred, as it facilitates thorough mixing of the first raw material, thereby aiding in the subsequent first reaction. After solid-liquid separation, washing with N,N-dimethylformamide (DMF) and ethanol is performed, with the first drying temperature and time preferably within the aforementioned ranges to facilitate solvent removal.

[0031] In one embodiment of this application, in step S1 above, the temperature of the first reaction is 130-150°C, and the time of the first reaction is 48-72 hours.

[0032] Oil bath heating is preferably used for the first reaction. Controlling the temperature and time of the first reaction within the aforementioned range helps improve the efficiency of the first reaction, thereby increasing the yield of the metal-organic framework material. The aforementioned temperature of the first reaction helps to ensure uniformity and size control of crystal growth, reducing structural defects caused by excessively fast or slow crystal growth. The aforementioned time of the first reaction ensures sufficient contact and reaction of the reactants, thus facilitating the formation of a complete framework structure.

[0033] In one embodiment of this application, in step S1 above, the organic ligand is selected from 2-aminoterephthalic acid, 2-vinylterephthalic acid, terephthalic acid, 2,5-dihydroxyterephthalic acid, 2-hydroxyterephthalic acid, monosodium 2-sulfonic acid terephthalate, p-mercaptoterephthalic acid, 2-methyl-1,4-phthalic acid, 1,4-naphthalenedicarboxylic acid, 2,2'-bipyridine-5,5'-dicarboxylic acid, trimesic acid, 4,4-azopyridine, 1,2-di(4-pyridyl)ethylene, 5,10,15,2 The first acid solution is selected from any one or more of 0-tetra(4-aminophenyl)porphyrin, imidazophenylporphyrin, tetra(4-fluorophenyl)porphyrin, and meso-tetra(4-carboxyphenyl)porphyrin; and / or, the zirconium salt is selected from any one or more of zirconium tetrachloride, zirconium sulfate, and zirconium nitrate; and / or, the first acid solution is selected from any one or more of hydrochloric acid, sulfuric acid, and nitric acid, and the molar concentration of the first acid solution is 6 to 12 mol / L; the first organic solvent is selected from any one or more of N,N-dimethylformamide, N-methylpyrrolidone, and dimethyl sulfoxide.

[0034] Preferably, the types of organic ligands, zirconium salts, organic solvents, and the type and molar concentration of the first acid solution are within the above-mentioned ranges, which facilitates the reaction between the zirconium salt and the organic ligands, thereby obtaining a structurally stable metal-organic framework material. Zirconium tetrachloride is further preferred as the zirconium salt, as it has high reactivity and good solubility, which helps to effectively react with the organic ligands to form a stable metal-organic framework material.

[0035] The preferred organic ligand is 2-aminoterephthalic acid, resulting in a metal-organic framework material, UiO-66-NH2, which possesses a stable crystal structure and high porosity, contributing to maintaining structural integrity during battery operation. The preferred metal-organic framework material has a pore size of 0.4–0.6 nm and a specific surface area of ​​100–400 m². 2 / g, preferably 200-400m 2 / g, which facilitates efficient lithium-ion transport within it. The NH2 group in UiO-66-NH2 introduces active sites, which help adsorb and stabilize lithium salt anions, promote lithium salt dissociation, and thus release more Li. + Ions are used for charge transport.

[0036] In one embodiment of this application, in step S1 above, the molar ratio of the organic ligand to the zirconium salt is 1:0.5 to 10. Preferably, the molar ratio of the organic ligand to the zirconium salt is within the above range, which helps to promote the integrity and stability of the framework structure, control the pore size and distribution of the framework during the growth process, and obtain a metal-organic framework material with sufficient porosity and maintaining structural stability, thereby improving the lithium-ion transport efficiency.

[0037] The preferred pH value for the first reaction is 6.2–7.1, which helps promote the dissolution of zirconium salt and the initiation of the reaction, as well as reduce the occurrence of side reactions. Furthermore, the first organic solvent serves as the reaction medium, ensuring the uniform dispersion and mixing of the first raw material.

[0038] In one embodiment of this application, step S2 further includes the following preparation method for pre-preparing dimethyl 2,6-pyridinedicarboxylate: esterification of a raw material comprising 2,6-pyridinedicarboxylic acid, a second acid solution, and a second organic solvent to obtain a second product; sequential solid-liquid separation and drying of the second product to obtain dimethyl 2,6-pyridinedicarboxylate; wherein the molar ratio of 2,6-pyridinedicarboxylic acid to the volume of the second acid solution is 3–10:1 mol / mL, the second acid solution is concentrated sulfuric acid with a mass fraction ≥70%, and the second organic solvent is N,N-dimethylformamide; the esterification reaction temperature is 90–140°C, and the esterification reaction time is 24–60 h; the second drying temperature is 100–160°C, and the second drying time is 24–60 h.

[0039] The above-described preparation method for dimethyl 2,6-pyridinedicarboxylate helps to improve the yield and quality of dimethyl 2,6-pyridinedicarboxylate. Preferably, 2,6-pyridinedicarboxylate is dissolved in a second organic solvent to obtain a mixture; concentrated sulfuric acid solution is added to the mixture, and an esterification reaction is carried out using an oil bath heating method to obtain a second product. The second product is then subjected to solid-liquid separation, washing with deionized water, and subsequent drying to obtain dimethyl 2,6-pyridinedicarboxylate.

[0040] Preferably, the molar ratio of 2,6-pyridinedicarboxylic acid to the volume of the second acid solution is within the above-mentioned range, which helps to promote the esterification reaction of 2,6-pyridinedicarboxylic acid to obtain dimethyl 2,6-pyridinedicarboxylic acid. Preferably, the second acid solution is concentrated sulfuric acid with a mass fraction of ≥70%, preferably ≥98%, which helps to accelerate the esterification reaction, increase the reaction rate, shorten the reaction time, and also helps to reduce side reactions, thereby improving the purity and yield of dimethyl 2,6-pyridinedicarboxylic acid. Using oil bath heating for the esterification reaction, preferably within the above-mentioned temperature range, helps to uniformly heat the reactants, reduces side reactions or product decomposition caused by local overheating, and thus helps to improve the homogeneity and quality of dimethyl 2,6-pyridinedicarboxylic acid. Preferably, the esterification reaction time is within the above-mentioned range, which helps to improve the yield and quality of dimethyl 2,6-pyridinedicarboxylic acid. Preferably, 2,6-pyridinedicarboxylic acid is dissolved in N,N-dimethylformamide, which helps to promote the esterification reaction by stabilizing the reaction intermediate and lowering the activation energy, thereby increasing the reaction rate and efficiency. In the esterification reaction, the presence of N,N-dimethylformamide facilitates the formation of the desired ester bond between concentrated sulfuric acid and pyridinedicarboxylic acid molecules, generating dimethyl 2,6-pyridinedicarboxylic acid (PDME). Preferably, the temperature and time for the second drying are within the above-mentioned ranges, which helps to remove water.

[0041] In one embodiment of this application, step S2 further includes: mixing dimethyl 2,6-pyridine dicarboxylate and a third organic solvent to obtain a mixture; subjecting the mixture and the metal-organic framework material to a second reaction, solid-liquid separation, and a third drying process in sequence to obtain a solid-state battery electrolyte material; wherein the third organic solvent is selected from any one or more of N,N-dimethylformamide, N-methylpyrrolidone, and dimethyl sulfoxide; the temperature of the third drying is 100–130°C, and the time of the third drying is 24–60 h.

[0042] Preferredly, dimethyl 2,6-pyridinedicarboxylate is mixed with the third organic solvent, which helps to uniformly disperse the dimethyl 2,6-pyridinedicarboxylate in the third organic solvent, thereby facilitating subsequent reactions with metal-organic framework materials. After solid-liquid separation, the mixture is washed with deionized water and then subjected to a third drying process. Preferably, the temperature and time of the third drying are within the above-mentioned range, which helps to remove water and solvent.

[0043] In one embodiment of this application, the temperature of the second reaction is 90–140°C, the time of the second reaction is 24–60 h; and / or, the molar ratio of 2,6-pyridine dicarboxylic acid dimethyl ester to the metal-organic framework material is 1–6:1–15.

[0044] The second reaction is preferably carried out with stirring at the temperature described above. This helps to ensure the uniform dispersion of dimethyl 2,6-pyridinedicarboxylate in the metal-organic framework material and promotes a complete reaction between the two. Excessively high temperatures may accelerate the reaction but also promote side reactions, while excessively low temperatures may lead to incomplete reactions. Preferably, the temperature of the second reaction is within the above-mentioned range, resulting in a rapid and complete reaction. These second reaction conditions contribute to the formation of an optimized metal-organic framework material channel structure and enhanced active metal sites, making the dissociation of lithium salt in the composite material more efficient and releasing more Li. + This improves the ionic conductivity of the solid-state battery electrolyte material. Controlling the conditions of the second reaction within the above range not only helps maintain the structural stability of the metal-organic framework material and reduce thermal decomposition at high temperatures, enhancing the overall stability of the material, but also helps improve the interfacial contact between the solid-state battery electrolyte material and the battery electrodes, reducing interfacial resistance and thus improving overall battery performance.

[0045] Dimethyl 2,6-pyridinedicarboxylate, as a dimethyl ester of a nitrogen-containing heterocyclic compound, not only contributes to increasing the chemical diversity of metal-organic frameworks (MOFs) but also facilitates the formation of additional coordination bonds between nitrogen atoms in its molecule and metal ions in the MOF, thereby altering the surface properties and pore structure of the framework. Preferably, the molar ratio of dimethyl 2,6-pyridinedicarboxylate to the MOF is within the aforementioned range. This not only helps improve the bonding strength between the two, enhancing the thermal and chemical stability of the composite material and thus improving the structural integrity of the MOF during battery charge-discharge cycles, but also helps to regulate the structure and chemical environment of the MOF channels, creating lower-barrier channels more conducive to lithium-ion transport, thereby improving the ionic conductivity of the solid-state battery electrolyte material, and consequently improving the battery's cycle performance, energy density, and safety. The active sites on dimethyl 2,6-pyridinedicarboxylate help capture anions in the lithium salt, promoting lithium salt dissociation, thereby further improving the ionic conductivity of the solid-state battery electrolyte material.

[0046] In another typical embodiment of this application, a solid-state battery electrolyte material is provided, which is prepared by the above-described preparation method.

[0047] The solid-state battery electrolyte material prepared using the above method exhibits high ionic conductivity, which reduces energy loss during charging and discharging, thereby improving the overall energy efficiency of the battery. Compared to liquid electrolytes, solid-state electrolytes possess higher chemical and thermal stability, enhancing the safety performance of solid-state batteries.

[0048] Preparation of solid electrolyte membrane: Solid battery electrolyte material, PEO, and LiTFSI were added to anhydrous acetonitrile at a mass ratio of 1:5:1. After stirring for 12 hours, the solution was poured into a mold and vacuum dried at 60°C for 48 hours. The solid electrolyte membrane was obtained by hot pressing. The ionic conductivity of the solid electrolyte membrane was 3.8 × 10⁻⁶. -5 ~4.8×10 -4 S / cm.

[0049] Preferably, the ionic conductivity of the solid-state battery electrolyte material is within the above-mentioned range, which helps to mitigate electrode material damage during charge-discharge cycles, reduce lithium dendrite formation, and thus extend the battery's lifespan.

[0050] In another typical embodiment of this application, a solid-state lithium-ion battery is provided, including a solid electrolyte material, which is the solid-state battery electrolyte material described above.

[0051] Solid-state lithium-ion batteries, including the aforementioned solid-state battery electrolyte materials, exhibit high energy density, cycle performance, and safety. Solid-state lithium-ion batteries using the novel solid-state electrolyte materials prepared by the above methods not only achieve significant improvements in safety, energy density, cycle stability, and temperature adaptability, but also demonstrate comprehensive advantages such as high interface compatibility and cost-effectiveness, thus enabling better applications in new energy vehicles, energy storage systems, and other fields.

[0052] The beneficial effects of this application will be further illustrated below with reference to the embodiments.

[0053] Example 1

[0054] Preparation of metal-organic framework materials: 5 mol of 2-aminoterephthalic acid, 4 mol of zirconium tetrachloride, 6 mL of N,N-dimethylformamide, and 1 mL of 11.7 mol / L hydrochloric acid were mixed under ultrasonic treatment to obtain the first raw material. The first raw material was subjected to a first reaction in an oil bath at 140 °C for 48 h, with a pH of 6.2, to obtain the first product. The first product was centrifuged to obtain a solid, which was washed three times with N,N-dimethylformamide and ethanol, respectively, and dried in a vacuum oven at 100 °C for 24 h to obtain the metal-organic framework material UiO-66-NH2.

[0055] Preparation of dimethyl 2,6-pyridinedicarboxylate: 5 mol of 2,6-pyridinedicarboxylic acid, 1 mL of 98% concentrated sulfuric acid and 20 mL of a second organic solvent were subjected to an esterification reaction to obtain a second product. The second product was separated into solid and liquid phases, washed five times with deionized water, and dried in a vacuum oven at 100°C for 24 h to obtain dimethyl 2,6-pyridinedicarboxylate (PDME).

[0056] Preparation of solid-state battery electrolyte material: 6 mol of dimethyl 2,6-pyridinedicarboxylate was dissolved in 100 mL of N,N-dimethylformamide, and then 18 mol of UiO-66-NH2 was dissolved in the mixed solution. The mixture was stirred at 90 °C for 24 h for a second reaction. After the reaction was completed, solid-liquid separation was performed. The mixture was washed three times with ethanol and then dried in a vacuum oven at 120 °C for 24 h to obtain the solid-state battery electrolyte material, denoted as UiO-66-PDME-1.

[0057] Example 2

[0058] Preparation of metal-organic framework materials: 4 mol of 2-aminoterephthalic acid, 3 mol of zirconium tetrachloride, 5 mL of N,N-dimethylformamide, and 6 mL of 10.2 mol / L hydrochloric acid were mixed under ultrasonic treatment to obtain the first raw material. The first raw material was subjected to a first reaction in an oil bath at 150 °C for 60 h, with a pH of 6.4, to obtain the first product. The first product was centrifuged to obtain a solid, which was washed three times with N,N-dimethylformamide and ethanol, and then dried in a vacuum oven at 100 °C for 24 h to obtain the metal-organic framework material UiO-66-NH2.

[0059] Preparation of dimethyl 2,6-pyridinedicarboxylate: 5 mol of 2,6-pyridinedicarboxylic acid, 0.9 mL of 98% concentrated sulfuric acid and 20 mL of a second organic solvent were subjected to an esterification reaction to obtain a second product. The second product was separated into solid and liquid phases, washed five times with deionized water, and dried in a vacuum oven at 100 °C for 24 h to obtain dimethyl 2,6-pyridinedicarboxylate (PDME).

[0060] Preparation of solid-state battery electrolyte material: 5.2 mol of dimethyl 2,6-pyridinedicarboxylate was dissolved in 100 mL of N,N-dimethylformamide, and then 24.8 mol of UiO-66-NH2 was dissolved in the mixed solution. The mixture was stirred at 90 °C for 24 h for a second reaction. After the reaction was completed, solid-liquid separation was performed. The mixture was washed three times with ethanol and then dried in a vacuum oven at 100 °C for 24 h to obtain the solid-state battery electrolyte material, denoted as UiO-66-PDME-2.

[0061] Example 3

[0062] Preparation of metal-organic framework materials: 6 mol of 2-aminoterephthalic acid, 5 mol of zirconium tetrachloride, 7 mL of N,N-dimethylformamide, and 3 mL of 9.8 mol / L hydrochloric acid were mixed under ultrasonic treatment to obtain the first raw material. The first raw material was subjected to a first reaction in an oil bath at 130 °C for 72 h, with a pH of 6.5, to obtain the first product. The first product was centrifuged to obtain a solid, which was washed three times with N,N-dimethylformamide and ethanol, respectively, and dried in a vacuum oven at 100 °C for 24 h to obtain the metal-organic framework material UiO-66-NH2.

[0063] Preparation of dimethyl 2,6-pyridinedicarboxylate: 5 mol of 2,6-pyridinedicarboxylic acid, 0.8 mL of 98% concentrated sulfuric acid and 20 mL of a second organic solvent were subjected to an esterification reaction to obtain a second product. The second product was separated into solid and liquid phases, washed five times with deionized water, and dried in a vacuum oven at 100 °C for 24 h to obtain dimethyl 2,6-pyridinedicarboxylate (PDME).

[0064] Preparation of solid-state battery electrolyte material: 4.7 mol of dimethyl 2,6-pyridinedicarboxylate was dissolved in 100 mL of N,N-dimethylformamide, and then 23.5 mol of UiO-66-NH2 was dissolved in the mixed solution. The mixture was stirred at 90 °C for 24 h for a second reaction. After the reaction was completed, solid-liquid separation was performed. The mixture was washed three times with anhydrous ethanol and then dried in a vacuum oven at 130 °C for 24 h to obtain the solid-state battery electrolyte material, denoted as UiO-66-PDME-3.

[0065] Example 4

[0066] The difference from Example 1 is that the molar ratio of 2,6-pyridine dicarboxylic acid dimethyl ester to the metal-organic framework material is 2:1, and the solid-state battery electrolyte material UiO-66-PDME-4 is finally obtained.

[0067] Example 5

[0068] The difference from Example 1 is that the molar ratio of 2,6-pyridine dicarboxylic acid dimethyl ester to the metal-organic framework material is 6.5:1, resulting in the solid-state battery electrolyte material UiO-66-PDME-5.

[0069] Example 6

[0070] The difference from Example 1 is that 2,6-pyridinedicarboxylic acid dimethyl ester was dissolved in N,N-dimethylformamide, and then UiO-66-NH2 was dissolved in the mixed solution. The second reaction was carried out by stirring at 140°C for 30 hours, and finally the solid-state battery electrolyte material UiO-66-PDME-6 was obtained.

[0071] Example 7

[0072] The difference from Example 1 is that 2,6-pyridinedicarboxylic acid dimethyl ester was dissolved in N,N-dimethylformamide, and then UiO-66-NH2 was dissolved in the mixed solution. The second reaction was carried out by stirring at 145°C for 20 hours, and finally the solid-state battery electrolyte material UiO-66-PDME-7 was obtained.

[0073] Example 8

[0074] The difference from Example 1 is that the molar ratio of 2-aminoterephthalic acid and zirconium tetrachloride is 4:7, and the solid-state battery electrolyte material UiO-66-PDME-8 is finally obtained.

[0075] Example 9

[0076] The difference from Example 1 is that the molar ratio of 2-aminoterephthalic acid and zirconium tetrachloride is 3:7, resulting in the solid-state battery electrolyte material UiO-66-PDME-9.

[0077] Example 10

[0078] The difference from Example 1 is that the pH value of the first reaction is 6.9, the first product is obtained, and finally the solid-state battery electrolyte material UiO-66-PDME-12 is obtained.

[0079] Example 11

[0080] The difference from Example 1 is that the pH value of the first reaction is 7.2, the first product is obtained, and finally the solid battery electrolyte material UiO-66-PDME-13 is obtained.

[0081] Comparative Example 1

[0082] The electrolyte material for solid-state batteries is polyethylene oxide (PEO).

[0083] Test method:

[0084] Preparation of solid-state lithium-ion batteries: For the preparation of the solid electrolyte membrane in the example: solid battery electrolyte materials UiO-66-PDME-1, PEO and LiTFSI were added to anhydrous acetonitrile in a molar ratio of 1:5:1. After stirring for 12 hours, the solution was poured into a mold and vacuum dried at 60°C for 48 hours. The PEO-UiO-66-PDME-LiTFSI solid electrolyte membrane was obtained by hot pressing.

[0085] For the preparation of the comparative solid electrolyte membrane: PEO-LiTFSI electrolyte membrane was prepared by solution casting and hot pressing. PEO and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) were added to anhydrous acetonitrile solution at a molar ratio of 5:1. After stirring for 12 hours, the electrolyte solution was poured into a polytetrafluoroethylene mold and vacuum dried at 60°C for 48 hours. The solid electrolyte membrane was then formed by hot pressing.

[0086] 1. Preparation of high-voltage composite cathode: Ni83 cathode material, PEO-UiO-66-PDME-LiTFSI electrolyte solution and carbon nanotubes are mixed in N-methylpyrrolidone (NMP) solvent to form a uniform electrode slurry, which is then coated on aluminum current collector. After vacuum drying and pressing, a dense composite cathode is obtained.

[0087] 2. During battery assembly, graphite is used as the negative electrode, a double-layer electrolyte membrane (PEO-UiO-66-PDME-LiTFSI electrolyte membrane of the present application embodiment or PEO-LiTFSI electrolyte membrane of the comparative example) is used as the separator, and high-voltage composite material is used as the positive electrode. The loading of all positive electrodes exceeds 25 mg·cm³. -2 For pouch batteries, the thickness of the double electrolyte membrane is less than 40 μm, and the positive electrode loading is set to 5 mg·cm³. -2 (Double-sided coating) is used to assemble a 1Ah all-solid-state bare cell using hardware die-cutting. Finally, a polypropylene (PP) separator is used to wrap the bare cell to prevent short circuits, and the battery is encapsulated with an aluminum-plastic film under vacuum conditions.

[0088] Ionic conductivity test: The test was performed under pressure at 25℃ and 10MPa.

[0089] Cyclic performance test: 0.33C charge-discharge cycle at 25℃ (voltage range 2.8V-4.25V).

[0090] The test results are shown in Table 1.

[0091] Table 1

[0092]

[0093] Among them, the solid electrolyte membrane prepared from the solid electrolyte material of Comparative Example 1 has a smaller specific surface area (186 m²). 2 The battery has low ionic conductivity ( / g), resulting in poor first-cycle efficiency and internal resistance performance.

[0094] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0095] The solid-state battery electrolyte material of this application incorporates a metal-organic framework (MOF) to promote Li+ The migration of these molecules effectively improves the ionic conductivity of solid-state battery electrolyte materials, thereby enhancing the battery's cycle performance. On one hand, metal-organic framework materials enable the highly crystallized 2,6-pyridinedicarboxylic acid dimethyl ester entangled in traditional solid polymer electrolytes (SPEs) at room temperature (25–30 °C), thus reducing the polymer's crystallinity and promoting Li... + Migration; on the other hand, the active metal sites (OMS) in the metal-organic framework material channels can capture lithium salt anions, promote lithium salt dissociation, and make Li the dominant charge carrier in the channel. + Meanwhile, the low-barrier channels within metal-organic framework materials can further promote Li + Migration effectively improves the ionic conductivity of solid-state battery electrolyte materials. Using MOFs alone as electrolyte materials suffers from low ionic conductivity, low ion transport number, narrow electrochemical stability window, and poor interfacial contact. However, the preparation method described in this application combines dimethyl 2,6-pyridine dicarboxylate with a metal-organic framework, which serves as both the external framework and the main body of the composite solid-state electrolyte. The resulting solid-state battery electrolyte material (the modified composite solid-state electrolyte) exhibits excellent mechanical properties, a wide electrochemical window, and high ionic conductivity, thereby improving battery initial efficiency, capacity, and cycle performance while reducing internal resistance. Furthermore, the preparation method used in this application employs economical reagents and a relatively mild preparation process, reducing the use of harmful solvents.

[0096] The above are merely embodiments of the present invention and are not intended to limit the invention. Those skilled in the art will recognize that the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a solid-state battery electrolyte material, characterized in that, The preparation method includes: Step S1 involves reacting a first raw material comprising an organic ligand, a zirconium salt, a first acid solution, and a first organic solvent to obtain a metal-organic framework material; and Step S2 involves subjecting a second raw material, comprising dimethyl 2,6-pyridine dicarboxylate and the metal-organic framework material, to a second reaction to obtain a solid-state battery electrolyte material.

2. The preparation method according to claim 1, characterized in that, Step S1 further includes: mixing the first raw material with ultrasound to obtain a mixed first raw material; subjecting the first mixed raw material to the first reaction to obtain a first product; and subjecting the first product to solid-liquid separation and first drying to obtain the metal-organic framework material. The temperature of the first drying is 100-160℃, and the drying time is 24-60h.

3. The preparation method according to claim 1, characterized in that, In step S1, the temperature of the first reaction is 130–150°C, and the reaction time is 48–72 h.

4. The preparation method according to any one of claims 1 to 3, characterized in that, In step S1, the organic ligand is selected from 2-aminoterephthalic acid, 2-vinylterephthalic acid, terephthalic acid, 2,5-dihydroxyterephthalic acid, 2-hydroxyterephthalic acid, monosodium 2-sulfonic acid terephthalate, p-mercaptoterephthalic acid, 2-methyl-1,4-phthalic acid, 1,4-naphthalenedicarboxylic acid, 2,2'-bipyridine-5,5'-dicarboxylic acid, trimesolic acid, 4,4-azopyridine, 1,2-di(4-pyridyl)ethylene, 5,10,15,20-tetra(4-aminophenyl) The zirconium salt is selected from one or more of zirconium tetrachloride, imidazophenyl porphyrin, tetra(4-fluorophenyl)porphyrin, and tetra(4-carboxyphenyl)porphyrin; and / or, the zirconium salt is selected from one or more of zirconium tetrachloride, zirconium sulfate, and zirconium nitrate; and / or, the first acid solution is selected from one or more of hydrochloric acid, sulfuric acid, and nitric acid, and the molar concentration of the first acid solution is 6 to 12 mol / L; the first organic solvent is selected from one or more of N,N-dimethylformamide, N-methylpyrrolidone, and dimethyl sulfoxide.

5. The preparation method according to any one of claims 1 to 3, characterized in that, In step S1, the molar ratio of the organic ligand to the zirconium salt is 1:0.5 to 10.

6. The preparation method according to any one of claims 1 to 3, characterized in that, Step S2 further includes the following pre-preparation steps for the 2,6-pyridinedicarboxylic acid dimethyl ester: esterifying a raw material comprising 2,6-pyridinedicarboxylic acid, a second acid solution, and a second organic solvent to obtain a second product; subjecting the second product to solid-liquid separation and subsequent drying to obtain the 2,6-pyridinedicarboxylic acid dimethyl ester; wherein the molar ratio of the 2,6-pyridinedicarboxylic acid to the volume of the second acid solution is 3–10:1 mol / mL, the second acid solution is concentrated sulfuric acid with a mass fraction ≥70%, and the second organic solvent is N,N-dimethylformamide; the esterification reaction is carried out at a temperature of 90–140°C for 24–60 h; the second drying is carried out at a temperature of 100–160°C for 24–60 h.

7. The preparation method according to any one of claims 1 to 3, characterized in that, Step S2 further includes: mixing the 2,6-pyridine dicarboxylic acid dimethyl ester and a third organic solvent to obtain a mixture; subjecting the mixture and the metal-organic framework material to the second reaction, solid-liquid separation, and third drying in sequence to obtain the solid-state battery electrolyte material; wherein the third organic solvent is selected from any one or more of N,N-dimethylformamide, N-methylpyrrolidone, and dimethyl sulfoxide; the temperature of the third drying is 100-130°C, and the time of the third drying is 24-60 h.

8. The preparation method according to any one of claims 1 to 3, characterized in that, The temperature of the second reaction is 90–140°C, and the reaction time is 24–60 h. And / or, the molar ratio of the 2,6-pyridinedicarboxylic acid dimethyl ester to the metal-organic framework material is 1-6:1-15.

9. A solid-state battery electrolyte material, characterized in that, The solid-state battery electrolyte material is prepared by the preparation method according to any one of claims 1 to 8.

10. A solid-state lithium-ion battery, comprising a solid electrolyte material, characterized in that, The solid electrolyte material is the solid battery electrolyte material as described in claim 9.

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