Preparation method and application of self-repairing polymer solid electrolyte material based on dodeca-hydrogen bond

Abstract

The present invention relates to the technical field of lithium battery solid electrolytes, and specifically to a preparation method and application of a self-healing polymer solid electrolyte material based on dodecahydrogen bonds. The preparation method comprises: mixing a monomer containing an ether oxygen bond, a diisocyanate and a solvent, and performing a polymerization reaction under the action of a catalyst to obtain a polymer solution; adding a pyridine diamine compound and a solvent to the polymer solution to obtain a high molecular polymer solution; adding a lithium salt to the high molecular polymer solution to obtain an electrolyte solution; coating the electrolyte solution and then drying it to obtain a self-healing polymer solid electrolyte material based on dodecahydrogen bonds. The self-healing polymer solid electrolyte material based on dodecahydrogen bonds of the present invention has good mechanical strength, which can not only solve the internal stress problem caused by the volume expansion of the positive electrode material during the use of lithium metal batteries, but also avoid the short circuit problem of lithium metal batteries caused by the growth and penetration of lithium dendrites.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium battery solid electrolytes, and in particular to a preparation method and application of a self-repairing polymer solid electrolyte material based on dodeca-hydrogen bonds. Background Art

[0002] Lithium metal anode has high specific capacity (3860mAhg -1 ) and the most negative electrochemical site, are considered ideal materials to replace traditional graphite anodes and increase battery energy density, enabling the energy density requirements of electric vehicles for portable electronic products. However, the use of liquid electrolytes increases the safety risks of lithium metal batteries (LMBs) due to the flammability of organic solvents and the growth of dendrites at the lithium metal / electrolyte interface. Therefore, the use of solid-state electrolytes instead of organic liquid electrolytes can effectively inhibit the growth of lithium dendrites and improve battery safety, fundamentally addressing the safety issues of electric vehicles.

[0003] Inorganic solid electrolytes offer high ionic conductivity and thermal stability, but are limited by severe mechanical brittleness and high electrolyte-electrode interface impedance. Solid polymer electrolytes (SPEs) have been extensively studied due to their excellent mechanical flexibility and elasticity, which can inhibit the growth of Li dendrites. However, the stress and strain caused by the volume expansion of the cathode material during charge and discharge cycles, as well as the growth of lithium dendrites at the anode, can cause the SPE to rupture, severely affecting the cycling performance of lithium metal batteries. Summary of the Invention

[0004] In response to the problems existing in the prior art, the present invention provides a method for preparing and applying a self-healing polymer solid electrolyte material based on dodecahydrogen bonds. The method uses a monomer containing an ether oxygen bond and a diisocyanate as raw materials to obtain a polymer solution; introduces a pyridine diamine compound into the polymer solution to obtain a high molecular weight polymer solution; and mixes the high molecular weight polymer solution with a lithium salt, followed by a coating treatment, to obtain a self-healing polymer solid electrolyte material based on dodecahydrogen bonds. The self-healing polymer solid electrolyte material based on dodecahydrogen bonds prepared by the present invention has good mechanical strength and can not only solve the internal stress problem caused by the volume expansion of the positive electrode material during the use of lithium metal batteries, but also effectively avoid the short circuit problem of lithium metal batteries caused by the growth and penetration of lithium dendrites at the negative electrode, thereby greatly improving the durability and safety of the battery.

[0005] In order to achieve the above objectives, the technical solutions adopted in this application are:

[0006] The first object of the present invention is to provide a method for preparing a self-healing polymer solid electrolyte material based on dodeca-hydrogen bonds, comprising the following steps:

[0007] S1. Mixing a monomer containing an ether oxygen bond, a diisocyanate, a catalyst and a first solvent; under the action of the catalyst, the monomer containing an ether oxygen bond and the diisocyanate undergo a polymerization reaction to generate carbamate, thereby obtaining a polymer solution.

[0008] S2. Add a pyridinediamine compound and a second solvent to the polymer solution. The pyridinediamine compound can construct a dodecaplex hydrogen bond. After a chain extension reaction, the amino group in the pyridinediamine compound reacts with the isocyanate group in the diisocyanate to form a urea bond. In the process of forming the urea bond, the amino group and nitrogen atom of the pyridinediamine compound act as proton donors and proton acceptors to participate in and form hydrogen bonds. At the same time, the pyridinediamine compound introduces multiple hydrogen bonding points into the high molecular polymer chain, thereby forming a dodecaplex hydrogen bond to obtain a high molecular polymer solution; wherein, the mass ratio of the monomer containing an ether oxygen bond, the diisocyanate and the pyridinediamine compound is 80-100:8-10:1.

[0009] S3. Add lithium salt to the high molecular polymer solution to obtain an electrolyte solution; wherein the mass ratio of the high molecular polymer solution to the lithium salt is 25 to 30:1; if the ratio is too high, the lithium salt content is relatively small, resulting in low lithium ion conductivity; if the ratio is too low, the lithium salt is excessive, resulting in lithium salt precipitation, thereby reducing the mechanical strength of the self-healing polymer solid electrolyte material based on dodecahydrogen bonds.

[0010] S4. The electrolyte solution is coated and then dried to obtain a self-repairing polymer solid electrolyte material based on dodeca-hydrogen bonds.

[0011] Preferably, the pyridinediamine compound is selected from at least one of 4-methoxypyridine-2,6-diamine, 2,6-diaminopyridine, 5,5'-diamino-2,2'-bipyridine, 4,4'-diamino-2,2'-bipyridine, and 1,1'(4-methoxypyridine-2,6-diyl)diurea; the pyridine of the pyridinediamine compound is connected to amino groups on both sides, and the amino groups participate in the reaction as functional groups.

[0012] Preferably, the polymerization reaction conditions are: stirring at 40° C. to 60° C. for 6 h to 10 h under the protection of inert gas.

[0013] Preferably, the diisocyanate is selected from at least one of hexamethylene diisocyanate and toluene diisocyanate; wherein, a diisocyanate with higher symmetry is conducive to the full progress of the polymerization reaction.

[0014] Preferably, the monomer containing an ether oxygen bond is selected from at least one of tannic acid, polyethylene glycol, polytetrahydrofuran, polyester polyol, polycaprolactone, polyvinyl alcohol, and hydroxy-terminated polybutadiene.

[0015] Preferably, the amount of catalyst added is 0.2% to 1% of the mass of the polymer solution.

[0016] Preferably, the catalyst is selected from dibutyltin dilaurate, dimethylstannate, dibutylstannate or dibutyltin diacetate.

[0017] Preferably, the first solvent and the second solvent are both selected from at least one of N,N-dimethylacetamide, dichloromethane, toluene, xylene, chloroform, dimethyl carbonate, and ethylene carbonate.

[0018] Preferably, the mass ratio of the monomer containing an ether oxygen bond, the diisocyanate and the solvent is 10:1:10-20.

[0019] Preferably, the mass ratio of the pyridinediamine compound to the solvent is 1:80-100.

[0020] Preferably, the lithium salt is composed of an organic lithium salt and lithium nitrate, and the organic lithium salt is selected from lithium hexafluorophosphate, lithium difluorooxalatoborate, lithium bis(trifluoromethylsulfonyl)imide or lithium bis(fluorosulfonyl)imide; among them, lithium nitrate can construct a stable solid electrolyte phase interface on the negative electrode side and effectively stabilize the lithium metal negative electrode interface.

[0021] Preferably, the mass ratio of the organic lithium salt to lithium nitrate is 10 to 12:1; wherein, a small amount of lithium nitrate can effectively form a stable negative electrode interface protective layer to avoid side reactions, but too much lithium nitrate will precipitate from the self-healing polymer solid electrolyte material based on dodecahydrogen bonds, thereby reducing the overall mechanical properties of the self-healing polymer solid electrolyte material based on dodecahydrogen bonds.

[0022] Preferably, the drying operation is: after spreading the polymer solution on a polytetrafluoroethylene plate, drying it at 50° C. to 70° C. for 20 h to 24 h under the protection of inert gas.

[0023] The second object of the present invention is to provide a self-repairing polymer solid electrolyte material based on dodeca-hydrogen bonds prepared by the above preparation method.

[0024] Preferably, the thickness of the self-healing polymer solid electrolyte material based on dodecahydrogen bonds is 50 μm to 200 μm; if the thickness is too high, the impedance of the self-healing polymer solid electrolyte material based on dodecahydrogen bonds will be too large, affecting the performance of the solid-state lithium battery; if the thickness is too low, the self-healing polymer solid electrolyte material based on dodecahydrogen bonds will be easily punctured by lithium dendrites deposited on the negative electrode of the solid-state lithium battery, causing a short circuit.

[0025] The third object of the present invention is to provide a solid-state lithium metal battery made of a positive electrode material, a negative electrode material and a self-healing polymer solid electrolyte material based on dodeca-hydrogen bonds.

[0026] Preferably, the positive electrode material is selected from at least one of sulfided polyacrylonitrile, sulfur-carbon composite material, lithium iron phosphate, nickel-cobalt-manganese ternary material, and lithium cobalt oxide.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. The present invention provides a method for preparing a self-repairing polymer solid electrolyte material based on dodecahydrogen bonds, comprising mixing a monomer containing an ether oxygen bond, a diisocyanate, a catalyst, and a first solvent. Under the action of a catalyst, the monomer containing an ether oxygen bond and the diisocyanate undergo a polymerization reaction to form a carbamate, thereby obtaining a polymer solution. A pyridine diamine compound and a second solvent are added to the polymer solution, and through a chain extension reaction, the amino group in the pyridine diamine compound reacts with the isocyanate group in the diisocyanate to form a urea bond. In the process of forming the urea bond, the amino group and the nitrogen atom of the pyridine diamine compound serve as Proton donors and proton acceptors participate in and form hydrogen bonds, and at the same time, the pyridinediamine compound introduces multiple hydrogen bonding points into the polymer chain, thereby forming dodecaple hydrogen bonds to obtain a polymer solution; the mass ratio of the monomer containing ether oxygen bonds, diisocyanate and pyridinediamine compound is 80-100:8-10:1; lithium salt is added to the polymer solution to obtain an electrolyte solution; the mass ratio of the polymer solution to the lithium salt is 25-30:1; the electrolyte solution is coated and then dried to obtain a self-healing polymer solid electrolyte material based on dodecaple hydrogen bonds. The present invention achieves strong interaction between polymer molecular chains by introducing a monomer chain extender capable of realizing dodecahydrogen bonds, namely a pyridinediamine compound, into the polymer chain, thereby significantly enhancing the overall mechanical strength of the self-healing polymer solid electrolyte material based on dodecahydrogen bonds. This not only solves the internal stress problem caused by the volume expansion of the positive electrode material during the use of the solid-state lithium metal battery, but also effectively avoids the short circuit problem of the lithium metal battery caused by the growth and penetration of the negative electrode lithium dendrites, thereby greatly improving the durability and safety of the battery.

[0029] 2. The self-healing polymer solid electrolyte material based on dodecahydrogen bonds of the present invention increases the disorder of the molecular chain arrangement of the self-healing polymer solid electrolyte material based on dodecahydrogen bonds through the interaction between the carbamate group and the lithium salt and the dynamic nature of the dodecahydrogen bonds, effectively reducing the crystallinity of the self-healing polymer solid electrolyte material based on dodecahydrogen bonds. This structural adjustment greatly promotes the free migration of lithium ions in the self-healing polymer solid electrolyte material based on dodecahydrogen bonds, significantly reducing the obstacles in the ion transport process, thereby further improving the ionic conductivity of the self-healing polymer solid electrolyte material based on dodecahydrogen bonds.

[0030] Furthermore, the present invention achieves efficient dissociation of lithium salts and rapid transport of lithium ions by incorporating lithium-ion-conducting functional carbamate groups into the polymer structure. This design optimizes the ion channels within the self-healing polymer solid electrolyte material based on dodeca-hydrogen bonds, lowering the energy barrier for lithium-ion migration. This significantly improves ionic conductivity while also enhancing the overall performance of solid-state lithium metal batteries.

[0031] 3. The self-healing polymer solid electrolyte material based on dodecahydrogen bonds of the present invention has a dodecahydrogen bond structure, which gives it good interface self-repairing ability. During the charge and discharge process of the solid-state lithium metal battery, if tiny cracks or damage occur, the dodecahydrogen bonds and carbamate groups in the self-healing polymer solid electrolyte material based on dodecahydrogen bonds can respond quickly and repair the damage by reforming hydrogen bonds, thereby ensuring the integrity of the solid-state lithium metal battery interface. This is attributed to the dynamic interaction mechanism of the breaking and recovery of the hydrogen bonds between the dodecahydrogen bonds and the carbamate groups within the molecule. This mechanism can not only effectively repair various interface defects and microcracks between the self-healing polymer solid electrolyte material based on dodecahydrogen bonds and the electrode, but also significantly enhance the interface compatibility of the solid-state lithium metal battery, thereby giving the solid-state lithium metal battery ultra-long cycle stability and excellent high-rate performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a scanning electron microscope image of the surface of the self-healing polymer solid electrolyte material based on dodeca-hydrogen bonds prepared in Example 10.

[0033] Figure 2 This is a scanning electron microscope image of the cross section of the self-healing polymer solid electrolyte material based on dodeca-hydrogen bonds prepared in Example 10.

[0034] Figure 3 This is a graph showing the tensile fracture strength of the self-healing polymer solid electrolyte material based on dodeca-hydrogen bonds prepared in Examples 1 to 10.

[0035] Figure 4 Graphs showing the ionic conductivity of the self-healing polymer solid electrolyte materials based on dodeca-hydrogen bonds prepared in Examples 1 to 10.

[0036] Figure 5 This is a diagram of the long-cycle performance of a nickel-cobalt-manganese ternary-lithium metal battery assembled with the self-healing polymer solid electrolyte material based on dodecahydrogen bonds prepared in Example 4.

[0037] Figure 6 This is a long cycle performance diagram of a nickel-cobalt-manganese ternary-lithium metal battery assembled with the self-healing polymer solid electrolyte material based on dodecahydrogen bonds prepared in Example 5.

[0038] Figure 7 This is a diagram of the long-cycle performance of a nickel-cobalt-manganese ternary-lithium metal battery assembled with the self-healing polymer solid electrolyte material based on dodecahydrogen bonds prepared in Example 6.

[0039] Figure 8 This is a long cycle performance diagram of a nickel-cobalt-manganese ternary-lithium metal battery assembled with the self-healing polymer solid electrolyte material based on dodecahydrogen bonds prepared in Example 7.

[0040] Figure 9 This is a long cycle performance diagram of a nickel-cobalt-manganese ternary-lithium metal battery assembled with the self-healing polymer solid electrolyte material based on dodecahydrogen bonds prepared in Example 8.

[0041] Figure 10 This is a long cycle performance diagram of a nickel-cobalt-manganese ternary-lithium metal battery assembled with the self-healing polymer solid electrolyte material based on dodecahydrogen bonds prepared in Example 9.

[0042] Figure 11 This is a long cycle performance diagram of a nickel-cobalt-manganese ternary-lithium metal battery assembled with the self-healing polymer solid electrolyte material based on dodecahydrogen bonds prepared in Example 10.

[0043] Figure 12 This is a diagram showing the long cycle performance of a lithium-lithium symmetric battery assembled with the self-healing polymer solid electrolyte material based on dodeca-hydrogen bonds prepared in Example 10. DETAILED DESCRIPTION

[0044] The following will clearly and completely describe the technical solution of the present invention in conjunction with the data in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0045] It should be noted that all professional terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention. Unless otherwise specified, the various raw materials, reagents, instruments and equipment used in the following embodiments of the present invention can be purchased from the market or prepared by existing methods.

[0046] In existing technologies, although solid polymer electrolytes (SPEs) have shown great potential in inhibiting lithium dendrite growth and improving battery safety, their insufficient mechanical properties and interfacial stability issues remain key factors restricting their practical application. Traditional SPE materials often find it difficult to maintain high ionic conductivity while possessing sufficient mechanical strength to withstand the stress challenges brought about by the volume expansion of the positive electrode material and the growth of lithium dendrites. In addition, the interfacial impedance between the electrolyte and the electrode is also an important factor affecting battery performance. High interfacial impedance will lead to an increase in the internal resistance of the battery, affecting the battery's charge and discharge efficiency and cycle stability.

[0047] In response to the problems existing in the prior art, the present invention provides a method for preparing a self-healing polymer solid electrolyte material based on dodecahydrogen bonds, comprising the following steps: mixing a monomer containing an ether oxygen bond, a diisocyanate, a catalyst and a first solvent; under the action of a catalyst, the monomer containing an ether oxygen bond and the diisocyanate undergo a polymerization reaction to generate carbamate to obtain a polymer solution; adding a pyridine diamine compound and a second solvent to the polymer solution; through a chain extension reaction, the amino group in the pyridine diamine compound reacts with the isocyanate group in the diisocyanate to generate a urea bond; in the process of forming the urea bond, the pyridine diamine compound Amino groups and nitrogen atoms act as proton donors and proton acceptors, participating in and forming hydrogen bonds. Simultaneously, pyridinediamine compounds introduce multiple hydrogen bonding points into the polymer chain, thereby forming dodecaple hydrogen bonds to obtain a polymer solution. The mass ratio of monomers containing ether oxygen bonds, diisocyanates, and pyridinediamine compounds is 80-100:8-10:1. Lithium salt is added to the polymer solution to obtain an electrolyte solution. The mass ratio of the polymer solution to the lithium salt is 25-30:1. The electrolyte solution is coated and then dried to obtain a self-healing polymer solid electrolyte material based on dodecaple hydrogen bonds.

[0048] The self-healing polymer solid electrolyte material based on dodeca-hydrogen bonds of the present invention has good mechanical strength, which can not only solve the internal stress problem caused by the volume expansion of the positive electrode material during the use of lithium metal batteries, but also avoid the short circuit problem of lithium metal batteries caused by the growth and penetration of lithium dendrites.

[0049] In order to enable those skilled in the art to more clearly understand the technical solution of the present disclosure, the technical solution of the present disclosure will be described in detail below with reference to specific embodiments:

[0050] Example 1

[0051] A method for preparing a self-repairing polymer solid electrolyte material based on dodeca-hydrogen bonds comprises the following steps:

[0052] S1. Weigh 2.0 g of polycaprolactone and 300 μL of hexamethylene diisocyanate, dissolve them in 6 mL of toluene, add 10 μL of dibutyltin dilaurate, heat at 60° C. and stir for 1 h to obtain a clear and transparent polymer solution.

[0053] S2. Weigh 25 mg of 5,5'-diamino-2,2'-bipyridine and add it to the polymer solution. Then add 2 mL of toluene to dilute it. Then add 2 mL of toluene every hour. After stirring and reacting at 50°C for 8 hours, a high molecular polymer solution is obtained. The molecular weight of the high molecular polymer is about 150,000.

[0054] S3. Under an inert gas atmosphere, add 1 g of lithium bis(fluorosulfonyl)imide and 0.1 g of lithium nitrate to the polymer solution, and add 2 mL of toluene to obtain an electrolyte solution.

[0055] S4. In an inert gas atmosphere, evenly spread the electrolyte solution onto a polytetrafluoroethylene (PTFE) plate and dry it at 50°C for 20 hours to obtain a self-healing polymer solid electrolyte material based on dodecahydrogen bonds. The thickness was controlled to be 200 μm and the material was cut into discs with a diameter of 16 mm.

[0056] The self-healing polymer solid electrolyte material based on dodeca-hydrogen bonds prepared in Example 1 was matched with lithium metal and lithium iron phosphate positive electrodes, and the battery was assembled and left to stand for 5 hours before testing its electrochemical performance. The mass percentage of active material in the positive electrode was 80 wt%, and the loading per unit area was 10 mg / cm 2 .

[0057] Example 2

[0058] A method for preparing a self-repairing polymer solid electrolyte material based on dodeca-hydrogen bonds comprises the following steps:

[0059] S1. Weigh 2.0 g of polytetrahydrofuran and 300 μL of toluene diisocyanate and dissolve them in 6 mL of dichloromethane. Add 10 μL of dibutyltin dilaurate and heat at 60°C with stirring for 1 h to obtain a clear and transparent polymer solution.

[0060] S2. Weigh 30 mg of 5,5'-diamino-2,2'-bipyridine and add it to the polymer solution, and add 2 mL of N,N-dimethylacetamide to dilute it. Then, add 2 mL of N,N-dimethylacetamide every hour. After stirring and reacting at 50°C for 8 hours, a high molecular polymer solution is obtained, and the molecular weight of the high molecular polymer is about 100,000.

[0061] S3. Under an inert gas atmosphere, 1.5 g of lithium salt lithium bis(fluorosulfonyl)imide and 0.1 g of lithium nitrate were added to the polymer solution, and 2 mL of N,N-dimethylacetamide was added to obtain an electrolyte solution.

[0062] S4. In an inert gas atmosphere, evenly spread the electrolyte solution onto a polytetrafluoroethylene plate and dry it at 50°C for 20 hours to obtain a self-healing polymer solid electrolyte material based on dodecahydrogen bonds. The thickness was controlled to be 100 μm and the material was cut into discs with a diameter of 16 mm.

[0063] The self-healing polymer solid electrolyte material based on dodeca-hydrogen bonds prepared in Example 2 was matched with lithium metal and lithium cobalt oxide positive electrodes, and the battery was assembled and left to stand for 5 hours before testing its electrochemical performance. The mass percentage of active material in the entire positive electrode was 80 wt%, and the loading per unit area was 10 mg / cm 2 .

[0064] Example 3

[0065] A method for preparing a self-repairing polymer solid electrolyte material based on dodeca-hydrogen bonds comprises the following steps:

[0066] S1. Weigh 3.0 g of polytetrahydrofuran and 280 μL of toluene diisocyanate, dissolve them in 6 mL of dichloromethane, add 15 μL of dibutyltin dilaurate, heat at 60° C. and stir for 1 h to obtain a clear and transparent polymer solution.

[0067] S2. Weigh 30 mg of 2,6-diaminopyridine and add it to the polymer solution, and add 2 mL of N,N-dimethylacetamide to dilute it. Then, add 2 mL of N,N-dimethylacetamide every hour. After stirring and reacting at 50°C for 8 hours, a high molecular polymer solution is obtained, and the molecular weight of the high molecular polymer is about 200,000.

[0068] S3. Under an inert gas atmosphere, 1.2 g of lithium salt lithium bis(fluorosulfonyl)imide and 0.3 g of lithium nitrate were added to the polymer solution, and 2 mL of N,N-dimethylacetamide was added to obtain an electrolyte solution.

[0069] S4. In an inert gas atmosphere, evenly spread the electrolyte solution onto a polytetrafluoroethylene (PTFE) plate and dry it at 50°C for 20 hours to obtain a self-healing polymer solid electrolyte material based on dodecahydrogen bonds. The thickness was controlled to be 150 μm and the material was cut into discs with a diameter of 16 mm.

[0070] The self-healing polymer solid electrolyte material based on dodeca-hydrogen bonds prepared in Example 3 was matched with lithium metal and nickel-cobalt-manganese ternary positive electrodes, and the battery was assembled and left to stand for 5 hours before testing its electrochemical performance. The mass percentage of active material in the entire positive electrode was 80 wt%, and the loading per unit area was 20 mg / cm 2 .

[0071] Example 4

[0072] A method for preparing a self-repairing polymer solid electrolyte material based on dodeca-hydrogen bonds comprises the following steps:

[0073] S1. Weigh 2.0 g of polyethylene glycol and 200 μL of toluene diisocyanate, dissolve them in 6 mL of dichloromethane, add 20 μL of dibutyltin dilaurate, heat at 60°C and stir for 1 h to obtain a clear and transparent polymer solution.

[0074] S2. Weigh 40 mg of 2,6-diaminopyridine and add it to the polymer solution, and add 2 mL of N,N-dimethylacetamide to dilute it. Then, add 2 mL of N,N-dimethylacetamide every hour. After stirring and reacting at 50°C for 8 hours, a high molecular polymer solution is obtained, and the molecular weight of the high molecular polymer is about 250,000.

[0075] S3. Under an inert gas atmosphere, add 1 g of lithium salt lithium bis(fluorosulfonyl)imide and 0.1 g of lithium nitrate to the polymer solution, and add 2 mL of N,N-dimethylacetamide to obtain an electrolyte solution.

[0076] S4. In an inert gas atmosphere, evenly spread the electrolyte solution onto a polytetrafluoroethylene plate and dry it at 50°C for 20 hours to obtain a self-healing polymer solid electrolyte material based on dodecahydrogen bonds. The thickness was controlled to be 180 μm and the material was cut into discs with a diameter of 16 mm.

[0077] The self-healing polymer solid electrolyte material based on dodeca-hydrogen bonds prepared in Example 4 was matched with lithium metal and nickel-cobalt-manganese ternary positive electrodes, and the battery was assembled and left to stand for 5 hours before testing its electrochemical performance. The mass percentage of active material in the entire positive electrode was 80 wt%, and the loading per unit area was 20 mg / cm 2 .

[0078] Example 5

[0079] A method for preparing a self-repairing polymer solid electrolyte material based on dodeca-hydrogen bonds comprises the following steps:

[0080] S1. Weigh 2.0 g of polyethylene glycol and 200 μL of hexamethylene diisocyanate, dissolve them in 10 mL of dichloromethane, add 20 μL of dibutyltin dilaurate, heat at 60° C. and stir for 1 h to obtain a clear and transparent polymer solution.

[0081] S2. Weigh 25 mg of 5,5'-diamino-2,2'-bipyridine and add it to the polymer solution. Then add 2 mL of N,N-dimethylacetamide to dilute it. Then, add 2 mL of N,N-dimethylacetamide every hour. After stirring and reacting at 50°C for 8 hours, a polymer solution is obtained. The molecular weight of the polymer is about 250,000.

[0082] S3. Under an inert gas atmosphere, add 1 g of lithium salt lithium bis(fluorosulfonyl)imide and 0.1 g of lithium nitrate to the polymer solution, and add 2 mL of N,N-dimethylacetamide to obtain an electrolyte solution.

[0083] S4. In an inert gas atmosphere, evenly spread the electrolyte solution onto a polytetrafluoroethylene (PTFE) plate and dry it at 50°C for 20 hours to obtain a self-healing polymer solid electrolyte material based on dodecahydrogen bonds. The thickness was controlled to be 150 μm and the material was cut into discs with a diameter of 16 mm.

[0084] The self-healing polymer solid electrolyte material based on dodeca-hydrogen bonds prepared in Example 5 was matched with lithium metal and nickel-cobalt-manganese ternary positive electrodes, and the battery was assembled and left to stand for 5 hours before testing its electrochemical performance. The mass percentage of active material in the entire positive electrode was 80 wt%, and the loading per unit area was 20 mg / cm 2 .

[0085] Example 6

[0086] A method for preparing a self-repairing polymer solid electrolyte material based on dodeca-hydrogen bonds comprises the following steps:

[0087] S1. Weigh 3.0 g of tannic acid and 150 μL of hexamethylene diisocyanate and dissolve them in 6 mL of ethylene carbonate. Add 10 μL of dibutyltin dilaurate and heat at 60° C. with stirring for 1 h to obtain a clear and transparent polymer solution.

[0088] S2. Weigh 25 mg of 2,6-diaminopyridine and add it to the polymer solution, then add 2 mL of ethylene carbonate to dilute it, and then add 2 mL of ethylene carbonate every hour. After stirring and reacting at 50° C. for 8 hours, a high molecular polymer solution is obtained, and the molecular weight of the high molecular polymer is about 300,000.

[0089] S3. Under an inert gas atmosphere, 1.5 g of lithium salt lithium bis(fluorosulfonyl)imide and 0.1 g of lithium nitrate were added to the polymer solution, and 2 mL of ethylene carbonate was added to obtain an electrolyte solution.

[0090] S4. In an inert gas atmosphere, evenly spread the electrolyte solution onto a polytetrafluoroethylene (PTFE) plate and dry it at 50°C for 20 hours to obtain a self-healing polymer solid electrolyte material based on dodecahydrogen bonds. The thickness was controlled to be 200 μm and the material was cut into discs with a diameter of 16 mm.

[0091] The self-healing polymer solid electrolyte material based on dodeca-hydrogen bonds prepared in Example 6 was matched with lithium metal and nickel-cobalt-manganese ternary positive electrodes, and the battery was assembled and left to stand for 5 hours before testing its electrochemical performance. The mass percentage of active material in the entire positive electrode was 80 wt%, and the loading per unit area was 20 mg / cm 2 .

[0092] Example 7

[0093] A method for preparing a self-repairing polymer solid electrolyte material based on dodeca-hydrogen bonds comprises the following steps:

[0094] S1. Weigh 2.5 g of polytetrahydrofuran and 180 μL of toluene diisocyanate, dissolve them in 6 mL of dichloromethane, add 10 μL of dibutyltin dilaurate, heat at 60° C. and stir for 1 h to obtain a clear and transparent polymer solution.

[0095] S2. Weigh 30 mg of 4,4'-diamino-2,2'-bipyridine and add it to the polymer solution, and add 2 mL of N,N-dimethylacetamide to dilute it. Then, add 2 mL of N,N-dimethylacetamide every hour. After stirring and reacting at 50°C for 8 hours, a high molecular polymer solution is obtained, and the molecular weight of the high molecular polymer is about 400,000.

[0096] S3. Under an inert gas atmosphere, 1.5 g of lithium salt lithium bis(trifluoromethylsulfonyl)imide) and 0.3 g of lithium nitrate were added to the polymer solution, and 2 mL of N,N-dimethylacetamide was added to obtain an electrolyte solution.

[0097] S4. In an inert gas atmosphere, evenly spread the electrolyte solution onto a polytetrafluoroethylene (PTFE) plate and dry it at 50°C for 20 hours to obtain a self-healing polymer solid electrolyte material based on dodecahydrogen bonds. The thickness was controlled to be 200 μm and the material was cut into discs with a diameter of 16 mm.

[0098] The self-healing polymer solid electrolyte material based on dodeca-hydrogen bonds prepared in Example 7 was matched with lithium metal and nickel-cobalt-manganese ternary positive electrodes. The mass percentage of active material in the entire positive electrode was 80 wt%, and the loading per unit area was 20 mg / cm 2 , assemble the battery and test its electrochemical performance after standing for 5 hours.

[0099] Example 8

[0100] A method for preparing a self-repairing polymer solid electrolyte material based on dodeca-hydrogen bonds comprises the following steps:

[0101] S1. Weigh 2.0 g of polyvinyl alcohol and 250 μL of hexamethylene diisocyanate, dissolve them in 10 mL of xylene, add 10 μL of dibutyltin dilaurate, heat at 60° C. and stir for 1 h to obtain a clear and transparent polymer solution.

[0102] S2. Weigh 30 mg of 4,4'-diamino-2,2'-bipyridine and add it to the polymer solution, and add 2 mL of N,N-dimethylacetamide to dilute it. Then, add 2 mL of N,N-dimethylacetamide every hour. After stirring and reacting at 50°C for 8 hours, a high molecular polymer solution is obtained, and the molecular weight of the high molecular polymer is about 450,000.

[0103] S3. Under an inert gas atmosphere, 0.8 g of lithium salt lithium bis(trifluoromethylsulfonyl)imide and 0.2 g of lithium nitrate were added to the polymer solution, and 2 mL of N,N-dimethylacetamide was added to obtain an electrolyte solution.

[0104] S4. In an inert gas atmosphere, evenly spread the electrolyte solution onto a polytetrafluoroethylene plate and dry it at 50°C for 20 hours to obtain a self-healing polymer solid electrolyte material based on dodecahydrogen bonds. The thickness was controlled to be 100 μm and the material was cut into discs with a diameter of 16 mm.

[0105] The self-healing polymer solid electrolyte material based on dodeca-hydrogen bonds prepared in Example 8 was matched with lithium metal and nickel-cobalt-manganese ternary positive electrodes. The mass percentage of active material in the entire positive electrode was 80 wt%, and the loading per unit area was 20 mg / cm 2 , assemble the battery and test its electrochemical performance after standing for 5 hours.

[0106] Example 9

[0107] A method for preparing a self-repairing polymer solid electrolyte material based on dodeca-hydrogen bonds comprises the following steps:

[0108] S1. Weigh 2.5 g of polytetrahydrofuran and 300 μL of hexamethylene diisocyanate, dissolve them in 10 mL of dichloromethane, add 10 μL of dibutyltin dilaurate, heat at 60° C. and stir for 1 h to obtain a clear and transparent polymer solution.

[0109] S2. Weigh 30 mg of 4,4'-diamino-2,2'-bipyridine and add it to the polymer solution. Then add 2 mL of N,N-dimethylacetamide to dilute it. Then, add 2 mL of N,N-dimethylacetamide every hour. After stirring and reacting at 50°C for 8 hours, a high molecular polymer solution is obtained. The molecular weight of the high molecular polymer is about 500,000.

[0110] S3. Under an inert gas atmosphere, 1.2 g of lithium salt lithium bis(trifluoromethylsulfonyl)imide) and 0.2 g of lithium nitrate were added to the polymer solution, and 2 mL of N,N-dimethylacetamide was added to obtain an electrolyte solution.

[0111] S4. In an inert gas atmosphere, evenly spread the electrolyte solution onto a polytetrafluoroethylene (PTFE) plate and dry it at 50°C for 20 hours to obtain a self-healing polymer solid electrolyte material based on dodecahydrogen bonds. The thickness was controlled to be 200 μm and the material was cut into discs with a diameter of 16 mm.

[0112] The self-healing polymer solid electrolyte material based on dodeca-hydrogen bonds prepared in Example 9 was matched with lithium metal and nickel-cobalt-manganese ternary positive electrodes. The mass percentage of active material in the entire positive electrode was 80 wt%, and the loading per unit area was 10 mg / cm 2 , assemble the battery and test its electrochemical performance after standing for 5 hours.

[0113] Example 10

[0114] A method for preparing a self-repairing polymer solid electrolyte material based on dodeca-hydrogen bonds comprises the following steps:

[0115] S1. Weigh 2.0 g of polytetrahydrofuran and 220 μL of hexamethylene diisocyanate, dissolve them in 6 mL of dichloromethane, add 10 μL of dibutyltin dilaurate, heat at 60° C. and stir for 1 h to obtain a clear and transparent polymer solution.

[0116] S2. Weigh 25 mg of 2,6-diaminopyridine and add it to the polymer solution, and add 2 mL of N,N-dimethylacetamide to dilute it. Then, add 2 mL of N,N-dimethylacetamide every hour. After stirring and reacting at 50°C for 8 hours, a high molecular polymer solution is obtained, and the molecular weight of the high molecular polymer is about 600,000.

[0117] S3. Under an inert gas atmosphere, 0.9 g of lithium salt lithium bis(fluorosulfonyl)imide and 0.2 g of lithium nitrate were added to the polymer solution, and 2 mL of N,N-dimethylacetamide was added to obtain an electrolyte solution.

[0118] S4. In an inert gas atmosphere, evenly spread the electrolyte solution onto a polytetrafluoroethylene plate and dry it at 50°C for 20 hours to obtain a self-healing polymer solid electrolyte material based on dodecahydrogen bonds. The thickness was controlled to 50 μm and the material was cut into discs with a diameter of 16 mm.

[0119] The self-healing polymer solid electrolyte material based on dodeca-hydrogen bonds prepared in Example 10 was matched with lithium metal and nickel-cobalt-manganese ternary positive electrodes.

[0120] The self-healing polymer solid electrolyte material based on dodeca-hydrogen bonds prepared in Example 10 was matched with lithium metal to form a lithium-lithium symmetric battery. After standing for 5 hours, its electrochemical performance was tested.

[0121] The mass percentage of active material in the entire positive electrode is 80wt%, and the loading per unit area is 10mg / cm 2 , assemble the battery and test its electrochemical performance after standing for 5 hours.

[0122] a. Transverse rupture strength test: The self-healing polymer solid electrolyte material based on dodecaple hydrogen bonds prepared in Examples 1 to 10 was cut into pieces with a transverse cross-sectional area of ​​1 mm 2 , a rectangular piece with a length of 50 mm was subjected to tensile testing at a rate of 5 mm / min using a tensile testing machine.

[0123] Lithium Metal Battery Assembly: Lithium metal batteries were assembled using the dodeca-hydrogen bond-based self-healing polymer solid electrolyte materials prepared in Examples 1 to 10. These lithium metal batteries used a commercial lithium sheet with a diameter of 16 mm as the negative electrode, and selected sulfurized polyacrylonitrile, a sulfur-carbon composite, lithium iron phosphate, a nickel-cobalt-manganese ternary material, and lithium cobalt oxide as the positive electrode. CR2032 battery cases were used for assembly.

[0124] b. Ionic conductivity test: Test the electrochemical impedance spectroscopy (EIS) of lithium metal batteries, analyze and evaluate the impedance results, and calculate the corresponding ionic conductivity.

[0125] c. Cycling Performance Test: After the assembled lithium metal battery was allowed to rest for 5 hours, the cycling performance test was performed at 25°C. The first two cycles were performed at a 0.2C charge and discharge rate to activate the lithium metal battery, followed by a charge and discharge cycle test at a 0.5C or 1C rate.

[0126] observe Figure 1It was concluded that the surface of the self-healing polymer solid electrolyte material based on dodecahydrogen bonds prepared in Example 10 of the present invention is smooth and dense, which can significantly improve the interface contact performance between the self-healing polymer solid electrolyte material based on dodecahydrogen bonds and the positive electrode and the negative electrode.

[0127] observe Figure 2 It was concluded that the self-healing polymer solid electrolyte material based on dodeca-hydrogen bonds prepared in Example 10 of the present invention has a dense cross-section and a non-porous structure, which is beneficial for preventing the growth of lithium dendrites.

[0128] observe Figure 3 and Figure 4 It was found that in Example 10, polytetrahydrofuran, hexamethylene diisocyanate, and 2,6-diaminopyridine were used as reactants, lithium bis(fluorosulfonyl)imide and lithium nitrate were used as lithium salts, and N,N-dimethylacetamide was used as solvent. The self-healing polymer solid electrolyte material based on dodecahydrogen bonds prepared had a higher transverse rupture strength of up to 69 MPa and an ionic conductivity of 6.5×10 -4 S / cm.

[0129] In terms of mechanical strength, as the molecular weight of the polymer increases, the mechanical strength of the self-healing polymer solid electrolyte material based on dodecahydrogen bonds increases. The reaction ratio of polytetrahydrofuran and hexamethylene diisocyanate and the amount of 2,6-diaminopyridine added in Example 10 optimize the molecular weight and intermolecular force of the self-healing polymer solid electrolyte material based on dodecahydrogen bonds, thereby improving the tensile strength. In terms of ionic conductivity, the lithium salt concentration and the crystallinity of the polymer in the self-healing polymer solid electrolyte material based on dodecahydrogen bonds have a significant effect on ionic conductivity. The ratio of lithium bis(fluorosulfonyl)imide and lithium nitrate in Example 10 provides the optimal ion migration number and conductivity. In terms of self-healing ability, the introduction of dodecahydrogen bonds provides a dynamic cross-linked network for the self-healing polymer solid electrolyte material based on dodecahydrogen bonds, so that the self-healing polymer solid electrolyte material based on dodecahydrogen bonds can achieve self-healing by breaking and reorganizing hydrogen bonds when damaged, which is poor in other embodiments due to the small number of hydrogen bonds.

[0130] Depend on Figure 5 、 Figure 6 、 Figure 7 、 Figure 8 、 Figure 9 、 Figure 10 as well as Figure 11The results show the influence of different reactants and reaction ratios on the cycle performance of nickel-cobalt-manganese ternary positive electrode batteries. Among them, the nickel-cobalt-manganese ternary positive electrode battery assembled with the self-healing polymer solid electrolyte material based on twelve-fold hydrogen bonds prepared in Example 10 still maintains a capacity retention rate of 93% after 700 cycles, indicating that the self-healing polymer solid electrolyte material based on twelve-fold hydrogen bonds prepared in Example 10 can effectively inhibit the growth of lithium dendrites and the decomposition of the electrolyte during repeated charge and discharge, and maintain good cycle stability. In other embodiments, due to inappropriate reactants or reaction ratios, the electrolyte is insufficiently stable, the capacity decays rapidly, and the cycle performance is poor.

[0131] In terms of reactant selection, the combination of polytetrahydrofuran, hexamethylene diisocyanate, and 2,6-diaminopyridine used in Example 10 can form a self-healing polymer solid electrolyte material based on dodecahydrogen bonds with high ionic conductivity, thereby improving the cycle performance of the nickel-cobalt-manganese ternary cathode battery. The introduction of dodecahydrogen bonds gives the self-healing polymer solid electrolyte material based on dodecahydrogen bonds self-healing ability, capable of repairing tiny cracks during the charge and discharge process and maintaining good interfacial stability, thereby improving the cycle life of the nickel-cobalt-manganese ternary cathode battery.

[0132] Regarding the influence of the reaction ratio, the mass ratio of the polymer solution to the lithium salt in Example 10 was 2:1. This ratio optimized the migration path of lithium ions and improved the ionic conductivity and cycling performance of the nickel-cobalt-manganese ternary cathode battery. A relatively high lithium salt concentration helps improve the ionic conductivity of the self-healing polymer solid electrolyte material based on dodecavalent hydrogen bonds, but an excessively high ratio can lead to lithium salt precipitation, affecting the performance of the nickel-cobalt-manganese ternary cathode battery.

[0133] In Example 10, the ratio of polymer to chain extender in the polymer solution is 80:8:1, which ensures the mechanical strength and self-healing ability of the self-healing polymer solid electrolyte material based on dodeca-hydrogen bonds, while ensuring its good ionic conductivity.

[0134] Depend on Figure 12 The results show that the lithium-lithium symmetrical battery of Example 10 has long cycle characteristics and excellent performance, with a cycle time of up to 1400h. This shows that the self-repairing and healing function of the self-healing polymer solid electrolyte material based on twelve hydrogen bonds prepared in Example 10 enables the interface integrity of the battery to be maintained well, thereby having excellent cycle performance. This is because polytetrahydrofuran, hexamethylene diisocyanate and 2,6-diaminopyridine have the strongest reaction activity, and the polymer molecular weight in the self-healing polymer solid electrolyte material based on twelve hydrogen bonds is the highest. In the lithium-lithium battery, when the current density is increased to 0.4mA / cm -2When the self-healing polymer solid electrolyte material based on dodeca-hydrogen bonds repairs the interface defects, the polarization voltage of the lithium-lithium battery begins to decrease. This shows that the self-healing polymer solid electrolyte material based on dodeca-hydrogen bonds is repairing the interface defects. By breaking and reorganizing the hydrogen bonds, the interface integrity is improved, thereby reducing the polarization voltage. In subsequent cycles, the stable interface between the self-healing polymer solid electrolyte material based on dodeca-hydrogen bonds and the electrode enables the lithium-lithium battery to exhibit excellent long-cycle characteristics.

[0135] Although the preferred embodiment of the present invention has been described, those skilled in the art will be able to make other changes and modifications to these embodiments once they are aware of the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiment and all changes and modifications that fall within the scope of the present invention.

[0136] It is obvious that those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications of the present invention fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A method for preparing a self-repairing polymer solid electrolyte material based on dodeca-hydrogen bonds, characterized in that: The following steps are involved: Mixing a monomer containing an ether oxygen bond, a diisocyanate, a catalyst, and a first solvent; and polymerizing the monomer containing an ether oxygen bond and the diisocyanate under the action of the catalyst to form a carbamate, thereby obtaining a polymer solution; A pyridinediamine compound and a second solvent are added to the polymer solution. After a chain extension reaction, the amino group in the pyridinediamine compound reacts with the isocyanate group in the diisocyanate to form a urea bond. During the urea bond formation process, the amino group and nitrogen atom of the pyridinediamine compound act as a proton donor and a proton acceptor to participate in and form a hydrogen bond. Simultaneously, the pyridinediamine compound introduces multiple hydrogen bonding points into the polymer chain, thereby forming a dodecaplex hydrogen bond, thereby obtaining a polymer solution. The mass ratio of the monomer containing an ether oxygen bond, the diisocyanate and the pyridine diamine compound is 80-100:8-10:1; Adding lithium salt to the high molecular polymer solution to obtain an electrolyte solution; wherein the mass ratio of the high molecular polymer solution to the lithium salt is 25 to 30:1; The electrolyte solution is coated and then dried to obtain a self-repairing polymer solid electrolyte material based on dodeca-hydrogen bonds.

2. The method for preparing a self-repairing polymer solid electrolyte material based on dodeca-hydrogen bonds according to claim 1, characterized in that: The pyridinediamine compound is at least one selected from 4-methoxypyridine-2,6-diamine, 2,6-diaminopyridine, 5,5'-diamino-2,2'-bipyridine, 4,4'-diamino-2,2'-bipyridine, and 1,1'(4-methoxypyridine-2,6-diyl)diurea.

3. The method for preparing a self-repairing polymer solid electrolyte material based on dodeca-hydrogen bonds according to claim 1, characterized in that: The polymerization reaction conditions are: stirring at 40°C to 60°C for 6h to 10h under the protection of inert gas.

4. The method for preparing a self-repairing polymer solid electrolyte material based on dodeca-hydrogen bonds according to claim 1, characterized in that: The diisocyanate is selected from at least one of hexamethylene diisocyanate and toluene diisocyanate.

5. The method for preparing a self-repairing polymer solid electrolyte material based on dodeca-hydrogen bonds according to claim 1, characterized in that: The monomer containing ether oxygen bond is selected from at least one of tannic acid, polyethylene glycol, polytetrahydrofuran, polyester polyol, polycaprolactone, polyvinyl alcohol and terminal hydroxyl polybutadiene.

6. The method for preparing a self-repairing polymer solid electrolyte material based on dodeca-hydrogen bonds according to claim 1, characterized in that: The lithium salt consists of an organic lithium salt and lithium nitrate, and the organic lithium salt is selected from lithium hexafluorophosphate, lithium difluorooxalatoborate, lithium bis(trifluoromethylsulfonyl)imide or lithium bis(fluorosulfonyl)imide.

7. The method for preparing a self-repairing polymer solid electrolyte material based on dodeca-hydrogen bonds according to claim 6, characterized in that: The mass ratio of the organic lithium salt to the lithium nitrate is 10-12:

1.

8. A self-repairing polymer solid electrolyte material based on dodeca-hydrogen bonds prepared by the preparation method according to any one of claims 1 to 7.

9. The self-repairing polymer solid electrolyte material based on dodeca-hydrogen bonds according to claim 8, characterized in that: The thickness of the self-repairing polymer solid electrolyte material based on dodeca-hydrogen bonds is 50 μm to 200 μm.

10. A solid-state lithium metal battery, characterized in that: It is made of a positive electrode material, a negative electrode material and the self-repairing polymer solid electrolyte material based on dodeca-hydrogen bonds as claimed in claim 8.

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