Preparation method of lithium ion solid-state battery with interpenetrating network structure
By using materials such as cyclodextrin and maleic anhydride in lithium batteries to prepare polymer electrolyte membranes with interpenetrating network structures, the shortcomings of existing solid electrolyte materials in lithium batteries in terms of ionic conductivity, mechanical strength and thermal stability are solved, and the performance improvement of high-performance lithium batteries is achieved.
Patent Information
- Application Number
- CN202510403547.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-01
- Publication Date
- 2025-06-17
AI Technical Summary
The existing solid electrolyte materials of lithium battery batteries have shortcomings in terms of ionic conductivity, mechanical strength and thermal stability, and it is difficult to meet the needs of high-performance lithium batteries.
The polymer electrolyte membrane with an interpenetrating network structure is prepared by thermal polymerization using materials such as cyclodextrin and maleic anhydride. The cross-linking network is constructed through sulfhydryl Michael addition reaction and radical polymerization to improve the ionic conductivity, mechanical strength and thermal stability of the material.
It significantly improves the ionic conductivity, mechanical strength and thermal stability of lithium-ion solid-state batteries, improves the cycling performance and discharge specific capacity of the batteries, and ensures the stable performance of the batteries in high temperature environments.
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of the preparation of solid electrolytes for lithium batteries, and particularly relates to a preparation method of a lithium-ion solid battery with an interpenetrating network structure. Background Art
[0002] Natural biomass and its derivatives have excellent physical and chemical properties due to the diversity of their structures and components and the abundance of functional groups, which provides unlimited potential for the development of a new generation of lithium batteries.
[0003] Patent CN118572183A discloses a preparation of a self-healing nanocomposite polymer electrolyte and a lithium battery using this electrolyte. The nanocomposite polymer electrolyte disclosed in the present invention includes a lithium salt, a hyperbranched monomer, a modified inorganic nanoparticle, and a polymer monomer.
[0004] Cyclodextrin (CD) is a cyclic polysaccharide with a barrel-shaped structure, and is a widely used, inexpensive, and biocompatible material. It has been proven that cyclodextrin is also a very versatile molecule in polymer science. Cyclodextrin is compatible with a series of polymer technologies, and by using a thermal polymerization method, a thiol-ene click chemical reaction occurs between reactants to obtain a solid electrolyte material with an interpenetrating network structure. Summary of the Invention
[0005] The object of the present invention is to provide a preparation method of a polymer solid electrolyte with a microphase separation structure. Since styrene has a strong electron-withdrawing group and maleic anhydride has a strong electron-donating group, the two tend to form an alternating copolymer.
[0006] The technical solution of the present invention is: a preparation method of a lithium-ion solid battery with an interpenetrating network structure, which is characterized by including the following steps:
[0007] A. In a flask equipped with a magnetic stirrer, a thermometer, and a nitrogen protection device, sequentially add the weighed β-cyclodextrin, maleic anhydride, dimethylformamide (DMF), first stir well to dissolve each reactant, then raise the temperature for reaction for a period of time. After the reaction cools to room temperature, precipitate the reaction solution with chloroform, a light yellow product appears, then filter this product, wash and purify it, and vacuum dry the obtained light yellow product and recrystallize it to obtain maleic anhydride-modified β-cyclodextrin (MAH-β-CD) as a yellow crystal.
[0008] B. Add polyethylene glycol diacrylate, N-methylpyrrolidone, 4-aminobenzamidoxime, 3-amino-2-fluorobenzonitrile, and triethylamine to a reaction kettle according to a certain mass ratio and react at an appropriate temperature.
[0009] C. Then, add maleic anhydride-modified β-cyclodextrin (MAH-β-CD), pentaerythritol tetrakis(3-mercaptopropionate) (PETMP), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), polycarbonate (with a fixed content of 10%) according to a certain mass ratio, and carry out the reaction at an appropriate temperature. Continuously add the thermal initiator azobisisobutyronitrile, stir again to obtain the precursor solution, ultrasonically disperse the precursor solution to make it uniform, and then pour the solution evenly into a polytetrafluoroethylene plate and carry out thermal polymerization to obtain a membrane called the polymer electrolyte membrane.
[0010] D. Assemble the battery and test its discharge specific capacity, cycling performance, and ionic conductivity at a current density of 1C.
[0011] As a preferred technical solution of the present invention, in step A, the mass ratio of the β-cyclodextrin, maleic anhydride, and dimethylformamide is 9.4 - 11.8: 7.8 - 11.8: 60 - 100.
[0012] As a preferred technical solution of the present invention, in step A, the stirring time is 10 - 50 min.
[0013] As a preferred technical solution of the present invention, in step A, heat up to 80 - 100 °C and react for 6 - 10 h.
[0014] As a preferred technical solution of the present invention, in step A, the detergent is one or several of acetone and distilled water, and wash and purify one to three times.
[0015] As a preferred technical solution of the present invention, in step A, the pale yellow product is dried in a vacuum drying oven at 30 - 80 °C for 12 - 36 h.
[0016] As a preferred technical solution of the present invention, in step B, the polyethylene glycol diacrylate, N-methylpyrrolidone, 4-aminobenzamidoxime, 3-amino-2-fluorobenzonitrile, and triethylamine are mixed according to a mass ratio of 100 - 120: 500 - 800: 5 - 12: 2.5 - 5: 0.03 - 0.6, and react at 80 - 90 °C for 60 - 120 minutes.
[0017] As a preferred technical solution of the present invention, in step B, the polyethylene glycol diacrylate is selected from PEGDA1000, 2000, 3000, 4000.
[0018] As a preferred technical solution of the present invention, in step C, maleic anhydride modified β-cyclodextrin (MAH-β-CD), pentaerythritol tetra(3-mercaptopropionate) (PETMP), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and polycarbonate are mixed in a mass ratio of 10-13:4.5-14.5:7-21:2-20, and reacted at 80-90 °C for 60-120 minutes.
[0019] As a preferred technical solution of the present invention, in step C, the mass portion of the photoinitiator is 8-12.
[0020] As a preferred technical solution of the present invention, in step C, the stirring time after adding the initiator is 0.5-1.5 h.
[0021] As a preferred technical solution of the present invention, in step C, the precursor solution is ultrasonically treated for 10-30 min.
[0022] As a preferred technical solution of the present invention, in step C, the thermal polymerization temperature is 50-80 °C, and the thermal polymerization time is 8-12 h.
[0023] I. Reaction mechanism
[0024] 1. Amino-allyl addition reaction
[0025] Reaction of polyethylene glycol diacrylate with 4-aminobenzamidoxime: In this reaction, the double bond of polyethylene glycol diacrylate undergoes an addition reaction with the amino group of 4-aminobenzamidoxime. This reaction proceeds through a nucleophilic addition mechanism, in which the amino group acts as a nucleophile to attack the double bond, forming a new carbon-nitrogen bond. This process not only introduces a functional amidoxime group but also enhances the intermolecular interaction force, providing more active sites for subsequent polymerization.
[0026] Reaction of polyethylene glycol diacrylate with 3-amino-2-fluorobenzonitrile: Similarly, the reaction between polyethylene glycol diacrylate and 3-amino-2-fluorobenzonitrile is also completed through the addition of the amino group to the double bond. This step not only introduces a fluorine-containing benzonitrile group, increasing the polarity of the molecule, but also improves the chemical stability and hydrophobicity of the material through the introduction of fluorine atoms.
[0027] 2. Thiol-Michael addition reaction and polymerization
[0028] Thiol-Michael addition reaction: In this step, maleic anhydride-modified β-cyclodextrin (MAH-β-CD), pentaerythritol tetra(3-mercaptopropionate) (PETMP), and modified polyethylene glycol diacrylate participate in the reaction. As a strong nucleophile, the thiol attacks the double bond in maleic anhydride, and the residual double bonds of the modified polyethylene glycol diacrylate undergo Michael addition reaction. This process not only constructs a complex cross-linked network structure but also further enhances the hydrophilicity and ionic conductivity of the material by introducing multiple functional groups such as carboxyl and hydroxyl groups. Azobisisobutyronitrile decomposes to generate free radicals, initiating the growth of polymer chains, which determines the molecular weight distribution and physical properties of the final polymer.
[0029] II. Technical effects
[0030] 1. Improve ionic conductivity
[0031] Increase ionic transport channels: Functional groups introduced through the above reactions, such as amidoxime, fluorobenzonitrile, and β-cyclodextrin, can form specific ionic transport channels in the polymer matrix. These channels facilitate the rapid migration of lithium ions or other cations, thereby improving the ionic conductivity of the polymer electrolyte.
[0032] Optimize the ionic coordination environment: In particular, the introduction of amidoxime and fluorobenzonitrile groups can form stable coordination bonds with metal ions, reducing the activation energy of ion migration and further enhancing the ionic conductivity performance.
[0033] 2. Enhance mechanical strength and thermal stability
[0034] Construct a cross-linked network: The thiol-Michael addition reaction and subsequent free radical polymerization form a highly cross-linked network structure. This structure not only improves the mechanical strength of the polymer electrolyte, enabling it to withstand greater stress without breaking easily, but also enhances its thermal stability, ensuring that it can still maintain good morphology and performance under high-temperature environments.
[0035] Introduce rigid groups: The introduction of groups such as fluorobenzonitrile, due to its large steric hindrance effect, can restrict the movement of polymer segments, further improving the thermal stability of the material. Specific implementation manners
[0036] The present invention will be described in detail below in conjunction with specific implementation manners.
[0037] Example 1
[0038] 1. A preparation method of a lithium-ion solid-state battery with an interpenetrating network structure, characterized by comprising the following steps:
[0039] A. In a flask equipped with a magnetic stirrer, a thermometer, and a nitrogen protection device, add the weighed β-cyclodextrin (9.44 g), maleic anhydride (7.888 g), and dimethylformamide (DMF) (60 g) in sequence. First, stir well for 10 min to dissolve each reactant, then raise the temperature to 80 °C and react for 6 h. After the reaction cools to room temperature, precipitate the reaction solution with chloroform to obtain a pale yellow product. Then filter this product and wash and purify it once with acetone and distilled water respectively. Dry the obtained pale yellow product in a vacuum drying oven at 30 °C for 12 h, and then recrystallize it to obtain MAH-β-CD as yellow crystals.
[0040] B. Add 100 g of polyethylene glycol diacrylate, 500 g of N-methylpyrrolidone, 5 g of 4-aminobenzamidoxime, 2.5 g of 3-amino-2-fluorobenzonitrile, and 0.03 g of triethylamine to a reaction kettle for mixing, and react at 80 °C for 60 minutes.
[0041] C. Then add 10 g of maleic anhydride-modified β-cyclodextrin (MAH-β-CD), 4.9 g of pentaerythritol tetrakis(3-mercaptopropionate) (PETMP), 7 g of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), 2 g of polycarbonate (with a fixed content of 10%), and react at 80 °C for 30 minutes. Add 10 g of thermal initiator azobisisobutyronitrile and stir for another 0.5 h to obtain a precursor solution. Ultrasonic the precursor solution for 10 min to make it disperse evenly, and then pour this solution evenly onto a polytetrafluoroethylene plate and carry out thermal polymerization at 50 °C for 8 h to obtain a membrane called a polymer electrolyte membrane.
[0042] D. Assemble into a Li / / LFP battery and test its discharge specific capacity at a current density of 0.2C to be 158.9 mAh / g, the capacity retention rate after 100 cycles is 91.9%, and the ionic conductivity is 0.0043 S / cm.
[0043] Example 2
[0044] 1. A preparation method of a lithium-ion solid-state battery with an interpenetrating network structure, characterized by comprising the following steps:
[0045] A. In a flask equipped with a magnetic stirrer, a thermometer, and a nitrogen protection device, add the weighed β-cyclodextrin (11.34 g), maleic anhydride (9.80 g), and dimethylformamide (DMF) (80 g) in sequence. First, stir well for 30 min to dissolve each reactant, then raise the temperature to 90 °C and react for 8 h. After the reaction cools to room temperature, precipitate the reaction solution with chloroform to obtain a pale yellow product. Then filter this product and wash and purify it three times with acetone and distilled water respectively. Dry the obtained pale yellow product in a vacuum drying oven at 50 °C for 24 h, and then recrystallize it to obtain MAH-β-CD as yellow crystals.
[0046] B. Add 110 g of polyethylene glycol diacrylate, 700 g of N-methylpyrrolidone, 8 g of 4-aminobenzamidoxime, 3.5 g of 3-amino-2-fluorobenzonitrile, and 0.3 g of triethylamine into a reaction kettle for mixing, and react at 85 °C for 90 minutes.
[0047] C. Then add 11.7 g of maleic anhydride-modified β-cyclodextrin (MAH-β-CD), 9.8 g of pentaerythritol tetrakis(3-mercaptopropionate) (PETMP), 14.5 g of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), polycarbonate (the content is fixed at 10%), and react at 85 °C for 60 minutes. Add 8 g of thermal initiator azobisisobutyronitrile, stir again for 1 h to obtain a precursor solution, ultrasonicate the precursor solution for 20 min to make it uniformly dispersed, then pour this solution evenly into a polytetrafluoroethylene plate, and carry out thermal polymerization at 60 °C for 12 h to obtain a film called a polymer electrolyte membrane.
[0048] D. Assemble into a Li / / LFP battery, and test that its discharge specific capacity at a current density of 0.2C is 160.5 mAh / g, the capacity retention rate after 100 cycles is 93.5%, and the ionic conductivity is 0.0059 S / cm.
[0049] Example 3
[0050] 1. A preparation method of a lithium-ion solid-state battery with an interpenetrating network structure, which is characterized by including the following steps:
[0051] A. In a flask equipped with a magnetic stirrer, a thermometer and a nitrogen protection device, sequentially add weighed β-cyclodextrin (11.8 g), maleic anhydride (11.832 g), dimethylformamide (DMF) (100 g), first stir well for 50 min to dissolve each reactant, then raise the temperature to 100 °C and react for 10 h. After the reaction cools to room temperature, precipitate the reaction solution with chloroform, a light yellow product appears, then filter this product, and wash and purify it twice with acetone and distilled water respectively. The obtained light yellow product is dried in a vacuum drying oven at 80 °C for 36 h, and then recrystallized to obtain MAH-β-CD as a yellow crystal.
[0052] B. Add 120 g of polyethylene glycol diacrylate, 800 g of N-methylpyrrolidone, 12 g of 4-aminobenzamidoxime, 5 g of 3-amino-2-fluorobenzonitrile, and 0.6 g of triethylamine into a reaction kettle for mixing, and react at 90 °C for 120 minutes.
[0053] C. Then, add 13.4 g of maleic anhydride modified β-cyclodextrin (MAH-β-CD), 14.6 g of pentaerythritol tetrakis(3-mercaptopropionate) (PETMP), 21.5 g of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), 20 g of polycarbonate (with a fixed content of 10%), and react at 90 °C for 90 minutes. Add 12 g of thermal initiator azobisisobutyronitrile, and stir for another 1.5 h to obtain a precursor solution. Ultrasonicate the precursor solution for 30 min to disperse it evenly, and then pour the solution evenly into a polytetrafluoroethylene plate and thermally polymerize it at 80 °C for 36 h to obtain a membrane called a polymer electrolyte membrane.
[0054] D. Assemble into a Li / / LFP battery and test its discharge specific capacity at a current density of 0.2 C to be 163.5 mAh / g, the capacity retention rate after 100 cycles is 97.9%, and the ionic conductivity is 0.0078 S / cm.
[0055] Comparative Example 1
[0056] A. In a flask equipped with a magnetic stirrer, thermometer, and nitrogen protection device, sequentially add the weighed β-cyclodextrin (9.44 g), maleic anhydride (7.888 g), and dimethylformamide (DMF) (60 g). First, stir well for 10 min to dissolve each reactant, then raise the temperature to 80 °C and react for 6 h. After the reaction cools to room temperature, precipitate the reaction solution with chloroform to obtain a pale yellow product, then filter this product and wash and purify it once with acetone and distilled water respectively. Dry the obtained pale yellow product in a vacuum drying oven at 30 °C for 12 h, and then recrystallize it to obtain MAH-β-CD as yellow crystals.
[0057] B. Weigh 500 g of N-methylpyrrolidone as the solvent, 10 g of maleic anhydride modified β-cyclodextrin (MAH-β-CD), 4.9 g of pentaerythritol tetrakis(3-mercaptopropionate) (PETMP), 100 g of polyethylene glycol diacrylate (PEGDA1000), 7 g of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), 2 g of polycarbonate (with a fixed content of 10%). When the solution becomes clear and transparent after stirring, add 10 g of thermal initiator azobisisobutyronitrile, and stir for another 0.5 h to obtain a precursor solution. Ultrasonicate the precursor solution for 10 min to disperse it evenly, and then pour the solution evenly into a polytetrafluoroethylene plate and thermally polymerize it at 50 °C for 8 h to obtain a membrane called a polymer electrolyte membrane.
[0058] C. Assemble into a Li / / LFP battery and test its discharge specific capacity at a current density of 0.2 C to be 163.5 mAh / g, the capacity retention rate after 100 cycles is 97.9%, and the ionic conductivity is 0.0012 S / cm.
[0059] Assembled into a Li / / LFP battery, its discharge specific capacity was tested to be 150 mAh / g at a current density of 0.2 C, the capacity retention rate was 80.5% after 100 cycles, and the ionic conductivity was 0.003 S / cm.
Claims
1. A method for preparing a lithium-ion solid-state battery having an interpenetrating network structure, characterized in that The following steps are involved: A. In a flask equipped with a magnet, a thermometer and a nitrogen protection device, weighed β-cyclodextrin, maleic anhydride and dimethylformamide are added in sequence, and the reactants are first fully stirred to dissolve, and then the temperature is raised for a period of time. After the reaction is cooled to room temperature, the reaction solution is precipitated with chloroform to produce a light yellow product, which is then filtered, washed and purified. The obtained light yellow product is vacuum dried and recrystallized to obtain maleic anhydride-modified β-cyclodextrin (MAH-β-CD) as yellow crystals. B. Add polyethylene glycol diacrylate, N-methylpyrrolidone, 4-aminobenzamide oxime, 3-amino-2-fluorobenzonitrile and triethylamine into a reaction kettle according to a certain mass ratio, and react at a suitable temperature. C. Then, add maleic anhydride-modified β-cyclodextrin (MAH-β-CD), pentaerythritol tetrakis(3-mercaptopropionic acid), lithium bis(trifluoromethylsulfonyl imide), and polycarbonate (content fixed at 10%) in a certain mass ratio, react at a suitable temperature, continue to add thermal initiator azobisisobutyronitrile, stir again to obtain a precursor solution, ultrasonically disperse the precursor solution to make it uniform, then evenly pour the solution into a polytetrafluoroethylene plate, thermally polymerize, and the obtained membrane is called a polymer electrolyte membrane. D. Assemble the battery and test its discharge capacity, cycle performance and ionic conductivity at a current density of 1C.
2. The method for preparing a lithium-ion solid-state battery having an interpenetrating network structure according to claim 1, characterized in that: In step A, the mass ratio of β-cyclodextrin, maleic anhydride and dimethylformamide is 9.4-11.8:7.8-11.8:60-100.
3. The method for preparing a lithium-ion solid-state battery having an interpenetrating network structure according to claim 1, characterized in that: In step A, the stirring time is 10-50 min.
4. The method for preparing a lithium-ion solid-state battery having an interpenetrating network structure according to claim 1, characterized in that: In step A, the temperature is raised to 80-100° C. and the reaction is carried out for 6-10 hours.
5. The method for preparing a lithium-ion solid-state battery having an interpenetrating network structure according to claim 1, characterized in that: In step A, the detergent is one or more of acetone and distilled water, and the washing and purification are performed one to three times.
6. The method for preparing a lithium-ion solid-state battery having an interpenetrating network structure according to claim 1, characterized in that: In step A, the light yellow product is dried in a vacuum drying oven at 30-80° C. for 12-36 hours.
7. The method for preparing a lithium-ion solid-state battery having an interpenetrating network structure according to claim 1, characterized in that: In step B, the polyethylene glycol diacrylate, N-methylpyrrolidone, 4-aminobenzamide oxime, 3-amino-2-fluorobenzonitrile and triethylamine are mixed in a mass ratio of 100-120:500-800:5-12:2.5-5:0.03-0.6, and reacted at 80-90° C. for 60-120 minutes.
8. The method for preparing a lithium-ion solid-state battery having an interpenetrating network structure according to claim 1, characterized in that: In step B, the polyethylene glycol diacrylate is selected from PEGDA1000, 2000, 3000, 4000.
9. The method for preparing a lithium-ion solid-state battery having an interpenetrating network structure according to claim 1, characterized in that: In step C, the maleic anhydride-modified β-cyclodextrin (MAH-β-CD), pentaerythritol tetrakis(3-mercaptopropionate) (PETMP), lithium bis(trifluoromethylsulfonyl imide) (LiTFSI), and polycarbonate are mixed in a mass ratio of 10-13:4.5-14.5:7-21:2-20, and reacted at 80-90° C. for 60-120 minutes.
10. The method for preparing a lithium-ion solid-state battery having an interpenetrating network structure according to claim 1, characterized in that: In step C, the mass parts of the photoinitiator are 8-12.
11. The method for preparing a lithium-ion solid-state battery having an interpenetrating network structure according to claim 1, characterized in that: In step C, the stirring time after adding the initiator is 0.5-1.5h.
12. The method for preparing a lithium-ion solid-state battery having an interpenetrating network structure according to claim 1, characterized in that: In step C, the precursor solution is sonicated for 10-30 minutes.
13. The method for preparing a lithium-ion solid-state battery having an interpenetrating network structure according to claim 1, characterized in that: In step C, the thermal polymerization temperature is 50-80° C., and the thermal polymerization time is 8-12 hours.