Resin skeleton reinforced gel electrolyte as well as preparation method and application thereof

Abstract

The invention relates to a resin skeleton reinforced gel electrolyte as well as a preparation method and application thereof, and relates to the technical field of batteries. Comprising the following steps: (1) sequentially adding a solvent and a plasticizer into a polymer to obtain a first mixed solution; (2) soaking a porous resin skeleton in the first mixed solution to obtain a soaked porous resin skeleton; placing the soaked porous resin skeleton in deionized water, and then drying to obtain a porous resin skeleton reinforced gel film; and (3) soaking and activating the porous resin skeleton reinforced gel film in an electrolyte to obtain the resin skeleton reinforced gel electrolyte. According to the invention, a gel polymer is synthesized by using an impregnation precipitation method, and the gel polymer is combined with a porous resin skeleton by soaking, so that the resin skeleton reinforced gel electrolyte with high mechanical property and high electrical property is prepared.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a resin skeleton reinforced gel electrolyte and a preparation method and application thereof. Background Art

[0002] With the rapid expansion of secondary battery application scenarios, the comprehensive use capabilities of batteries have ushered in a comprehensive investigation. Traditional liquid electrolytes are prone to leakage during use, and the energy density and power density of the battery are subject to certain limitations. Solid-state batteries are one of the new battery technologies that solve such problems. They are highly safe, not prone to leakage and explosion, and have high energy density and charge and discharge efficiency; however, solid-state batteries have complex production processes and high costs, and the solid electrolyte and electrode materials are connected in a solid state. Therefore, the effective contact between the electrode and the electrolyte is weak, and the ion transport kinetics in the solid material are low, resulting in excessive interfacial impedance that affects electrical performance. Semi-solid gel electrolytes with good interface performance have the problems of low mechanical properties and difficulty in molding. In view of this, the present invention provides a resin skeleton reinforced gel electrolyte, a preparation method, and an application thereof. Summary of the Invention

[0003] In order to solve the problems of low mechanical properties and difficult molding of gel electrolytes, the present invention provides a resin skeleton reinforced gel electrolyte and a preparation method and application thereof.

[0004] The technical solution of the present invention to solve the above technical problems is as follows:

[0005] In a first aspect, a method for preparing a resin skeleton reinforced gel electrolyte comprises the following steps:

[0006] (1) adding a solvent and a plasticizer to the polymer in sequence to obtain a first mixed solution;

[0007] (2) soaking the porous resin skeleton in the first mixed solution to obtain a soaked porous resin skeleton; placing the soaked porous resin skeleton in deionized water, and then drying it to obtain a porous resin skeleton reinforced gel film;

[0008] (3) immersing the porous resin skeleton reinforced gel film in an electrolyte for activation to obtain a resin skeleton reinforced gel electrolyte.

[0009] The beneficial effects of the present invention are as follows: the present invention synthesizes a gel polymer by an impregnation precipitation method, combines the gel polymer with a porous resin skeleton by immersion, and prepares a resin skeleton reinforced gel electrolyte with high mechanical properties and high electrical properties.

[0010] On the basis of the above technical solution, the present invention can also be improved as follows.

[0011] Furthermore, the polymer in step (1) includes at least one of polyoxyethylene (PEO), polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), polymethyl methacrylate (PMMA), and polyacrylonitrile (PAN);

[0012] and\or, the solvent in step (1) comprises at least one of N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP), and dimethyl sulfoxide (DMSO);

[0013] and\or, the plasticizer in step (1) comprises at least one of dimethyl ether (DME), succinonitrile (SN), and dibutyl phthalate (DBP);

[0014] And\or, in step (1), the mass ratio of the solvent to the polymer is 1 to 6; and the plasticizer accounts for 10% to 50% of the mass of the polymer.

[0015] The beneficial effect of adopting the above further solution is that the material can be transformed from a hollow structure to a solid structure by using the gel infusion method, thereby improving the mechanical properties and at the same time improving the electrical properties of the material as a gel electrolyte.

[0016] Furthermore, the porous resin skeleton in step (2) accounts for 50% to 80% of the mass of the porous resin skeleton after soaking;

[0017] And\or, the pore size of the porous resin skeleton in step (2) is 1-3 microns.

[0018] Furthermore, step (2) includes the following specific steps:

[0019] The porous resin skeleton is immersed in the first mixed solution at a temperature of 30°C to 80°C for a time of 2 hours to 12 hours to obtain a soaked porous resin skeleton; the soaked porous resin skeleton is placed in deionized water and allowed to stand at room temperature for 12 hours to 24 hours, and then dried at a temperature of 30°C to 80°C for a drying time of 6 hours to 24 hours to obtain a porous resin skeleton reinforced gel film.

[0020] The beneficial effect of adopting the above further solution is that the present invention uses an impregnation precipitation method to synthesize a gel polymer, which has high electrolyte absorption and excellent electrical properties.

[0021] Furthermore, the electrolyte in step (3) includes at least one of LX-266, lithium hexafluorophosphate, and LiTFSI;

[0022] And\or, the parameters of the soaking activation in step (3) are: room temperature, time is 24h to 48h.

[0023] Furthermore, the porous resin skeleton is prepared by the following method: mixing the resin with a pore-forming agent and a curing agent in sequence to obtain a second mixed solution; curing the second mixed solution to obtain a resin film; soaking the resin film in deionized water and then drying it to obtain a porous resin skeleton.

[0024] The beneficial effect of adopting the above further solution is that the present invention uses a phase separation method to prepare a porous resin skeleton with different pore structures having excellent mechanical properties, thereby providing high mechanical properties for the gel electrolyte.

[0025] Furthermore, the resin includes at least one of epoxy resin bisphenol A (such as E51, E44), epoxy resin bisphenol F (such as EPIVKOTE 862), acrylic resin (special resin is JONCRYL 678), and multifunctional resin 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane;

[0026] and\or, the pore-forming agent comprises at least one of polyethylene glycol (PEG200, PEG400, PEG800, PEG1000), glucose, ethyl cellulose (EC), and N,N-dimethylformamide (DMF);

[0027] and\or, the curing agent comprises an amine curing agent (e.g., D400, PACM, DDM, TETA);

[0028] And\or, the mass ratio of the pore-forming agent to the resin is 1 to 4; the curing agent accounts for 20% to 60% of the mass of the resin.

[0029] Furthermore, the curing parameters of the second mixed solution are: temperature of 25°C to 180°C, time of 2h to 6h;

[0030] and\or, the thickness of the resin film is 50 μm to 300 μm;

[0031] And\or, the resin film is immersed in deionized water at room temperature for 24 to 48 hours;

[0032] And\or, the parameters for drying the resin film after immersion are: temperature of 30° C. to 80° C. and time of 6 hours to 24 hours.

[0033] In a second aspect, a resin skeleton reinforced gel electrolyte is provided. The resin skeleton reinforced gel electrolyte is prepared by the preparation method.

[0034] In a third aspect, an application of a resin skeleton reinforced gel electrolyte is provided, wherein the resin skeleton reinforced gel electrolyte is used in a structural energy storage composite material device; the structural energy storage composite material device includes any one of a structural lithium-ion battery and a structural capacitor. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Figure 1 shows the combination of the porous resin of the present invention and the porous resin skeleton and gel in different states; A is the porous resin; B is the porous resin after being soaked in gel; C is the porous resin after being soaked in deionized water; D is the porous resin skeleton reinforced gel film;

[0036] Figure 2 These are the SEM images of the porous resin, the SEM images of the porous resin-reinforced gel, and the EDS images of the porous resin-reinforced gel of the present invention; wherein, A is the SEM image of the porous resin; B is the SEM image of the porous resin-reinforced gel; and C is the EDS image of the porous resin-reinforced gel. DETAILED DESCRIPTION

[0037] The principles and features of the present invention are described below. The examples are only used to explain the present invention and are not intended to limit the scope of the present invention. Where specific techniques or conditions are not specified in the examples, the techniques or conditions described in the literature in this field or the product instructions are used. Where the manufacturers of the reagents or instruments used are not specified, they are all conventional products that can be purchased through regular channels.

[0038] Comparative Example 1

[0039] (1) Preparation of porous resin skeleton

[0040] The preparation method of the porous resin skeleton comprises the following steps:

[0041] Epoxy resin E51 and pore-forming agent DMF were stirred evenly at 20-40°C, with the mass ratio of epoxy resin to pore-forming agent DMF being 1:3; then curing agent polyetheramine D230 was added and stirred evenly, with the amount of curing agent D230 being 30% of the mass of epoxy resin E44, to obtain a mixture;

[0042] The obtained mixture was defoamed for 1 minute using a centrifuge at a speed of 2000 r / min and then poured into a special mold for curing at a curing temperature of 60°C for 2 hours and then at 80°C for 2 hours to obtain a solidified material. The naturally cooled solidified material was immersed in deionized water and allowed to stand for 24 hours to replace the DMF with water. The solidified material was then placed in an oven at 60°C for 24 hours to completely remove moisture, exposing the porous structure and obtaining a porous resin skeleton.

[0043] (2) Preparation of porous resin skeleton electrolyte

[0044] The preparation method of the porous resin skeleton electrolyte comprises the following steps:

[0045] The dried porous resin skeleton was immersed in LX-266 electrolyte (purchased from Duoduo Chemical Reagent Network) for 1 h to fully fill it.

[0046] Comparative Example 2

[0047] (1) Preparation of polymer electrolyte membrane

[0048] A method for preparing a polymer electrolyte membrane comprises the following steps:

[0049] PVDF-HFP and DMSO were stirred at 70°C in a mass ratio of 1:3 for 1 hour to form a transparent gel-like substance. Subsequently, a plasticizer, DME, was added to the solution at a concentration of 50% of the PVDF-HFP mass and stirred at 70°C for 4 hours. The solution was continuously cast onto a clean glass substrate and scraped with a plasterboard. The sample was then quickly immersed in deionized water for 24 hours and dried in an oven at 60°C for 12 hours to obtain a polymer electrolyte membrane.

[0050] (2) Preparation of gel electrolyte

[0051] The preparation method of the gel electrolyte comprises the following steps:

[0052] The dried samples were immersed in LX-266 electrolyte for 1 h to fully activate them.

[0053] Comparative Example 3

[0054] Compared with Comparative Example 1, except that the epoxy resin E51 is replaced by 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, the rest is the same as Comparative Example 1.

[0055] Example 1

[0056] A method for preparing a resin skeleton reinforced gel electrolyte comprises the following steps:

[0057] 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane was stirred evenly with the pore-forming agent EPG200 at 60°C, with the mass ratio of 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane to the pore-forming agent PEG200 being 1:3; then an amine curing agent PACM was added and stirred evenly, with the amount of the curing agent being 57.5% of the resin mass, to obtain a mixture; the obtained mixture was debubbled at a speed of 2000 r / min using a centrifuge for 1 minute and then poured into a special mold for curing at a curing temperature of 130°C for 1.5 hours and then at 180°C for 0.5 hours to obtain a cured product; the cured product after natural cooling was immersed in deionized water and allowed to stand for 24 hours to replace PEG200 with water; then the product was placed in a 60°C oven for 24 hours to completely remove moisture, expose the porous structure, obtain a porous resin sample, and slice it for use.

[0058] PVDF-HFP and DMF were stirred at 50°C for 1 hour in a mass ratio of 1:3 to form a transparent gel-like substance; then, 20% of the plasticizer DBP (dibutyl phthalate) of the mass of PVDF was added to the solution and stirred at 50°C for 2 hours. The stirred solution was poured onto the cut porous resin film and allowed to stand at 60°C for 24 hours to allow the solution to fully infiltrate. The soaked sample was then quickly placed in deionized water and allowed to stand for 24 hours. Dry in an oven at 60°C for 12 hours to obtain a porous resin skeleton reinforced gel film ( Figure 1 AD and Figure 2 AC).

[0059] Example 2

[0060] The 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane in Example 1 was replaced with epoxy resin E51, and the rest was the same as in Example 1.

[0061] Example 3

[0062] Compared with Example 1, except that PVDF-HFP and DMF are in a mass ratio of 1:4, the rest are the same as Example 1.

[0063] Example 4

[0064] Compared with Example 1, PVDF-HFP was replaced with an equal amount of polymethyl methacrylate (PMMA), and the rest was the same as Example 1.

[0065] Example 5

[0066] Compared with Example 1, PVDF-HFP was replaced with an equal amount of polyacrylonitrile (PAN), and the rest was the same as Example 1.

[0067] Example 6: Application Example

[0068] (1) Preparation of structural energy storage composite materials

[0069] The method for preparing a structural energy storage composite material includes the following steps: adding active material powders of positive electrode lithium iron phosphate and negative electrode graphite, a binder, and a conductive agent in an 8:1:1 mass ratio to an N-methylpyrrolidone solvent, wherein the weight ratio of solvent to material is 2.6:1. The stirred slurry is then applied to carbon fibers using a blade coating method to a thickness of 30 to 40 μm, and dried at 90°C until the solvent is completely evaporated. Finally, the slurry is cut to the required size and assembled into a laminated structure according to the form of the positive electrode, separator, and negative electrode. A porous resin skeleton is introduced into the laminated structure using a drainage method, and the structural energy storage composite material is then immersed in a first mixed solution obtained by sequentially adding a polymer to a solvent and a plasticizer. The solvent is removed using a phase inversion method, dried, and then immersed in an electrolyte to produce a structural energy storage composite material with a gel electrolyte structure.

[0070] Test example

[0071] (1) Performance test of thin film materials

[0072] Performance test of film materials: Excluding the electrolyte soaking step (to prevent the electrolyte from deteriorating in the air), dumbbell-shaped film mechanical parts (narrow in the middle and wide at both ends) were prepared according to the preparation processes of the comparative example and the embodiment for use. The films prepared above were tested using an LE5000 series electronic universal testing machine in accordance with the standard GBT1040 for the determination of tensile properties of plastics. The specific test method is as follows: Place the sample in the test machine fixture, ensuring that the clamping area is completely fixed and the clamping position is centered. The central axis of the sample is aligned with the loading axis to avoid eccentric force. The tensile rate is set according to the following: Tensile rate: The clamp movement speed is 2mm / min. The test sample is a dumbbell-shaped sheet structure with a thickness of 2mm. It is widened at both ends. The length of the widened part is b, the width is c, and the length of the middle effective section is a. Among them, a is about 30mm, b is about 20mm, and c is about 10mm. The width of the middle effective section is 3-5mm (preferably 5mm).

[0073] The measured mechanical properties are shown in Table 1:

[0074] Table 1 Dumbbell-shaped film tensile strength test results

[0075]

[0076] As can be seen from Table 1, by comparing the data of Comparative Examples 1 and 3 with Example 1, it can be found that the use of 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane can obtain a porous epoxy resin film with better mechanical properties; by comparing the data of multiple groups of examples, it can be found that by infusing the gel polymer into the porous resin to prepare a composite material by this method, a composite film with better mechanical properties can be obtained; by comparing with the examples of introducing polymers such as PMMA and PAN, it can be found that the introduction of PVDF-HFP can better play the advantages of this method and can better prepare a composite film with high mechanical properties; changing the experimental details (Example 3, etc.) can achieve further adjustment of the mechanical properties.

[0077] (2) Electrical performance test of structural energy storage composite materials

[0078] According to the porous resin / gel electrolyte preparation method of the embodiment, referring to the above structure energy storage composite material preparation process, a structure energy storage composite material with a size of 4×4 cm was prepared, and the electrical performance was tested using a blue electric test system. The following performance test results are shown in Table 2:

[0079] Table 2 Electrical performance test results of structural energy storage composite materials

[0080]

[0081] As shown in Table 2, by comparing the experimental results of Examples 1 and 2, the electrical performance of the structural energy storage composite material prepared using 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane is better than that of epoxy resin E51. This may be because the former can form a better dual-continuous phase system during the curing process, which is manifested in the structural energy storage composite material as being able to better exert electrolyte performance, thereby obtaining better electrical performance. By comparing Examples 1, 4, and 5, it is known that after introducing different polymer skeletons, better specific capacity can be generally obtained. However, due to the different characteristics of the polymers, the cycle performance obtained by PVDF-HFP is better, which may be due to its higher dielectric constant, which is conducive to the dissociation of lithium ions in lithium salts. In summary, the introduction of gel electrolytes into porous resins can better enhance the electrical properties of energy storage composite materials.

[0082] (3) Mechanical properties of structural energy storage composite materials

[0083] According to the porous resin preparation process of Examples 1 to 5 and with reference to the preparation process of the structural energy storage composite material, according to the composite material - tensile test method standard ASTM D3039, a laminated structure was used to prepare tensile test specimens, and the test was carried out using an LE5000 series electronic universal testing machine. The specific test method was carried out in accordance with the standard. The test results are as follows:

[0084] Table 3 Mechanical properties test results of structural energy storage composite material splines

[0085]

[0086] As can be seen from Table 3, by comparing the data of Comparative Examples 1 and 3 with Example 1, it can be seen that the use of 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane can obtain a structural energy storage composite material with better mechanical properties; by comparing the data of multiple groups of examples, it can be seen that by infusing the gel polymer into the porous resin to prepare a composite material by this method, a composite film with better mechanical properties can be obtained; by comparing with the examples of introducing polymers such as PMMA and PAN, it can be seen that the introduction of PVDF-HFP can better play the advantages of this method and can better prepare a structural energy storage composite material with high mechanical properties; by changing the experimental details (Example 3, etc.), the mechanical properties of the composite material can be further adjusted.

[0087] In summary, the present invention uses a phase separation method to prepare a porous resin skeleton with different pore structures and excellent mechanical properties, providing mechanical support for the gel electrolyte. A gel polymer is synthesized using an impregnation precipitation method, and the gel polymer is combined with the porous resin skeleton by immersion, resulting in a resin skeleton-reinforced gel electrolyte with high mechanical and electrical properties.

[0088] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A method for preparing a resin skeleton reinforced gel electrolyte, characterized in that: The steps include: (1) adding a solvent and a plasticizer to the polymer in sequence to obtain a first mixed solution; (2) soaking the porous resin skeleton in the first mixed solution to obtain a soaked porous resin skeleton; placing the soaked porous resin skeleton in deionized water, and then drying it to obtain a porous resin skeleton reinforced gel film; (3) immersing the porous resin skeleton reinforced gel film in an electrolyte for activation to obtain a resin skeleton reinforced gel electrolyte.

2. The method for preparing a resin skeleton reinforced gel electrolyte according to claim 1, characterized in that: The polymer in step (1) comprises at least one of polyoxyethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polymethyl methacrylate, and polyacrylonitrile; and\or, the solvent in step (1) comprises at least one of N,N-dimethylformamide, N-methylpyrrolidone, and dimethyl sulfoxide; And\or, the plasticizer in step (1) includes at least one of dimethyl ether, succinonitrile, and dibutyl phthalate; And\or, in step (1), the mass ratio of the solvent to the polymer is 1 to 6; and the plasticizer accounts for 10% to 50% of the mass of the polymer.

3. The method for preparing a resin skeleton reinforced gel electrolyte according to claim 1, characterized in that: The porous resin skeleton in step (2) accounts for 50% to 80% of the mass of the porous resin skeleton after soaking; And\or, the pore size of the porous resin skeleton in step (2) is 1-3 microns.

4. The method for preparing a resin skeleton reinforced gel electrolyte according to claim 1, characterized in that: Step (2) includes the following specific steps: The porous resin skeleton is immersed in the first mixed solution at a temperature of 30°C to 80°C for a time of 2 hours to 12 hours to obtain a soaked porous resin skeleton; the soaked porous resin skeleton is placed in deionized water and allowed to stand at room temperature for 12 hours to 24 hours, and then dried at a temperature of 30°C to 80°C for a drying time of 6 hours to 24 hours to obtain a porous resin skeleton reinforced gel film.

5. The method for preparing a resin skeleton reinforced gel electrolyte according to claim 1, characterized in that: The electrolyte in step (3) includes at least one of LX-266, lithium hexafluorophosphate, and LiTFSI; And\or, the parameters of the soaking activation in step (3) are: room temperature, time is 24h to 48h.

6. The method for preparing a resin skeleton reinforced gel electrolyte according to any one of claims 1 to 5, characterized in that: The porous resin skeleton is prepared by the following method: mixing resin with a pore-forming agent and a curing agent in sequence to obtain a second mixed solution; curing the second mixed solution to obtain a resin film; soaking the resin film in deionized water and then drying it to obtain a porous resin skeleton.

7. The method for preparing a resin skeleton reinforced gel electrolyte according to claim 6, characterized in that: The resin includes at least one of epoxy resin bisphenol A, epoxy resin bisphenol F, acrylic resin, and 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane; and\or, the pore-forming agent comprises at least one of polyethylene glycol, glucose, ethyl cellulose, and N,N-dimethylformamide; and\or, the curing agent comprises an amine curing agent; And\or, the mass ratio of the pore-forming agent to the resin is 1 to 4; the curing agent accounts for 20% to 60% of the mass of the resin.

8. The method for preparing a resin skeleton reinforced gel electrolyte according to claim 6, characterized in that: The curing parameters of the second mixed solution are: temperature of 25°C to 180°C, time of 2h to 6h; and\or, the thickness of the resin film is 50 μm to 300 μm; And\or, the resin film is immersed in deionized water at room temperature for 24 to 48 hours; And\or, the parameters for drying the resin film after immersion are: temperature of 30° C. to 80° C. and time of 6 hours to 24 hours.

9. A resin skeleton reinforced gel electrolyte, characterized in that: The resin skeleton reinforced gel electrolyte is prepared by the preparation method according to any one of claims 1 to 8.

10. An application of a resin skeleton reinforced gel electrolyte, characterized in that: The resin skeleton reinforced gel electrolyte according to claim 9 is used in a structural energy storage composite material device; the structural energy storage composite material device includes any one of a structural lithium-ion battery and a structural capacitor.

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