A three-dimensional crosslinked waterborne polymer binder, and a preparation method and application thereof

Abstract

The application provides a three-dimensional cross-linked water-based polymer binder as well as a preparation method and application thereof. The three-dimensional cross-linked polymer binder comprises a polymer solution A and a polymer solution B; raw materials for preparing the polymer solution A comprise the following components in parts by weight: 5-80 parts of a monomer of formula 1, 1-30 parts of a monomer of formula 2 and 10-60 parts of a monomer of formula 3; and raw materials for preparing the polymer solution B comprise the following components in parts by weight: 10-100 parts of the monomer of formula 1, 1-30 parts of the monomer of formula 2 and 10-90 parts of the monomer of formula 3. The three-dimensional cross-linked water-based polymer binder provided by the application has good flexibility and high bonding force, and is suitable for preparing a lithium ion battery negative electrode sheet, and thus a lithium ion battery with excellent performance is prepared.

Description

Technical Field

[0001] This invention belongs to the field of adhesive technology, specifically relating to a three-dimensional cross-linked aqueous polymer adhesive, its preparation method, and its application. Background Technology

[0002] Lithium-ion batteries offer significant advantages as energy storage devices, and polymer binders have a crucial impact on the electrochemical performance of lithium-ion battery electrodes. The binder acts as a bridge connecting the active material, conductive agent, and current collector, ensuring the electrode sheets possess good mechanical and processing properties, and maintaining the conductive network and mechanical integrity of the electrode during charge and discharge. Highly efficient binders must possess the following characteristics: strong adhesion, good flexibility, stable thermal and chemical properties, stable electrochemical performance, good resistance to electrolyte swelling, good dispersibility in slurry media, low cost, and safety and pollution-free operation.

[0003] Although binders account for a small proportion of electrodes, they are an indispensable raw material for the preparation of high-performance lithium-ion batteries. Currently, they are developing rapidly in fields such as energy storage and small power tools, with large demand. The requirements for long cycle life, high safety and temperature resistance of batteries are gradually increasing. Therefore, the development of new multifunctional binders is a key technology for the preparation of high-capacity, high-safety, long-cycle and low-cost lithium-ion batteries, and a technological driving force for the development of next-generation advanced energy storage devices.

[0004] CN110364734A discloses a high-performance aqueous compound lithium-ion battery anode binder, its preparation method, and its application. The preparation method of the anode binder includes the following steps: (1) modifying polyacrylic acid to obtain glycine-modified polyacrylic acid PAA-GA; (2) preparing the lithium-ion battery anode binder: mixing the PAA-GA obtained in step (1) with aqueous polyurethane to obtain the lithium-ion battery anode binder. The lithium-ion battery anode binder provided by this technical solution can be used in the preparation of lithium-ion battery anodes. Lithium-ion batteries assembled using this anode exhibit good comprehensive electrochemical performance, with characteristics such as high cycle capacity and good cycle stability.

[0005] CN105336959A discloses a method for preparing a conductive, high-bonding-strength aqueous binder for lithium-ion batteries. The method involves adding a hydrophilic monomer to deionized water, stirring until dissolved, introducing a protective gas to remove oxygen, adding an initiator, adding a lipophilic monomer dropwise, adding a crosslinking agent, continuing stirring, removing residual monomers under reduced pressure, and filtering with a filter cloth to obtain the conductive, high-bonding-strength aqueous binder for lithium-ion batteries. This technical solution provides a conductive, high-bonding-strength aqueous binder with high bonding strength, good inhibition of electrode expansion, and good conductivity.

[0006] Common binders such as polyvinylidene fluoride (PVDF), polyacrylic acid (PAA), and styrene-butadiene rubber (SBR) / sodium carboxymethyl cellulose (CMC) are all homopolymers in structure. In homopolymer systems, the mechanical strength of the binder and its ability to swell the electrolyte are contradictory. PVDF binders use N-methylpyrrolidone (NMP) as a dispersant; the volatilization of this organic solvent causes environmental pollution and is expensive. Using SBR as a binder requires the addition of CMC as a thickener; CMC has moderate viscosity and high brittleness, making the electrode prone to cracking during charge and discharge. Furthermore, SBR as a binder causes significant electrolyte swelling, and when applied to graphite and silicon-based novel anodes based on a point-to-point bonding mechanism, the repeated expansion and contraction of the graphite and silicon anodes during charge and discharge cycles makes the binder prone to losing its adhesive properties, leading to capacity loss, especially with deterioration in high-temperature storage and high-temperature cycling performance.

[0007] With the development of science and technology, water-based binders have become a trend in the lithium-ion battery industry. Among them, ion polymer binders are one of the important research directions of water-based binders. They have become a research hotspot in recent years because they can reduce impedance performance, but they still have disadvantages such as poor flexibility.

[0008] Therefore, how to provide an adhesive with good flexibility and high adhesion has become an urgent technical problem to be solved. Summary of the Invention

[0009] To address the shortcomings of existing technologies, the present invention aims to provide a three-dimensional cross-linked aqueous polymer binder, its preparation method, and its applications. In this invention, by designing the raw materials and content of polymer solutions A and B, an aqueous polymer binder with a three-dimensional cross-linked structure is prepared using polymer solutions A and B. The prepared three-dimensional cross-linked aqueous polymer binder exhibits good flexibility and high adhesion, making it suitable for preparing negative electrode sheets for lithium-ion batteries.

[0010] To achieve this objective, the present invention adopts the following technical solution:

[0011] In a first aspect, the present invention provides a three-dimensional cross-linked aqueous polymer adhesive, the three-dimensional cross-linked polymer adhesive comprising polymer solution A and polymer solution B;

[0012] The raw materials for preparing polymer solution A include the following components in parts by weight: 5-80 parts of monomer of formula 1, 1-30 parts of monomer of formula 2 and 10-60 parts of monomer of formula 3.

[0013] The raw materials for preparing the polymer solution B include the following components in parts by weight: 10-100 parts of monomer of formula 1, 1-30 parts of monomer of formula 2 and 10-90 parts of monomer of formula 3.

[0014] Formula 1 monomer is CHR 11 =CR 12 -CN,R 11 Selected from any one of H, Cl, Br or -CH3, R 12 Selected from any one of H, Cl, Br, -CH3, or -C6H4-;

[0015] Formula 2 monomer is CHR 21 =CR 22 -CONR 23 R 24 R 21 For H or -CH3, R 22 For H or -C6H5, R 23 It can be H, -C6H7, or -(CH2). n-1 CH3, n is an integer from 1 to 19, R 24 Selected from H, -C(CH3)2CH2-SO3M, -(CH2) m SO3P or -(CH2) n -CH3 is any one of them, M is selected from any one of Li, Na or K, P is Li or Na, and m is an integer from 0 to 14 (for example, it can be 0, 2, 4, 6, 8, 10, 12 or 14, etc.);

[0016] Formula 3 monomer is CHR 31 =CHCOOR 32 R 31 For H or CH3, R 32 It can be H or M, where M is Li, Na or K.

[0017] In this invention, a three-dimensional cross-linked structure is formed through the ionic bonding between polymer molecular chains in polymer solution A and polymer solution B, thereby preparing an aqueous polymer binder with a three-dimensional cross-linked structure. At the same time, by designing the raw materials for preparing polymer solution A and polymer solution B, -CN and -CO-N- groups are introduced into the binder, so that the prepared three-dimensional cross-linked aqueous polymer binder has good flexibility and high adhesion, and is suitable for preparing negative electrode sheets for lithium-ion batteries.

[0018] In this invention, by controlling the content of each component in the raw materials for preparing polymer solution A and polymer solution B within a specific range, the prepared three-dimensional cross-linked waterborne polymer binder exhibits good flexibility and high adhesion. If the content of monomer of Formula 1 is too low, the binder of the prepared three-dimensional cross-linked waterborne polymer is of low strength; if the content of monomer of Formula 1 is too high, the water solubility of the prepared three-dimensional cross-linked waterborne polymer binder is poor. If the content of monomer of Formula 2 is too low, the flexibility of the prepared three-dimensional cross-linked waterborne polymer binder is poor; if the content of monomer of Formula 2 is too high, the water solubility of the prepared three-dimensional cross-linked waterborne polymer binder is poor. If the content of monomer of Formula 3 is too low, the water solubility of the prepared three-dimensional cross-linked waterborne polymer binder is poor, or even insoluble in water, ultimately making it impossible to prepare a three-dimensional cross-linked waterborne polymer binder; if the content of monomer of Formula 3 is too high, the flexibility of the prepared three-dimensional cross-linked waterborne polymer binder is poor.

[0019] In this invention, the weight parts of the monomer of Formula 1 in the raw materials for preparing polymer solution A can be 5 parts, 10 parts, 20 parts, 30 parts, 40 parts, 50 parts, 60 parts, 70 parts or 80 parts, etc.

[0020] The weight parts of the monomer in Formula 2 can be 1 part, 2 parts, 5 parts, 7 parts, 10 parts, 12 parts, 15 parts, 18 parts, 20 parts, 23 parts, 25 parts, 27 parts or 30 parts, etc.

[0021] The weight parts of the monomer in Formula 3 can be 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts, or 60 parts, etc.

[0022] In the raw materials for preparing polymer solution B, the weight parts of the monomer of Formula 1 can be 10 parts, 20 parts, 30 parts, 40 parts, 50 parts, 60 parts, 70 parts, 80 parts, 90 parts, or 100 parts, etc.

[0023] The weight parts of the monomer in Formula 2 can be 1 part, 2 parts, 5 parts, 7 parts, 10 parts, 12 parts, 15 parts, 18 parts, 20 parts, 23 parts, 25 parts, 27 parts or 30 parts, etc.

[0024] The weight parts of the monomer in Formula 3 can be 10, 20, 30, 40, 50, 60, 70, 80 or 90 parts, etc.

[0025] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The purpose and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0026] As a preferred embodiment of the present invention, the monomer of Formula 1 is selected from methacrylonitrile and / or acrylonitrile.

[0027] Preferably, the monomer of Formula 2 is selected from any one or a combination of at least two of N,N-diethylacrylamide, acrylamide, or 2-acrylamide-2-phenylethanesulfonic acid.

[0028] Preferably, the monomer of Formula 3 is selected from any one or a combination of at least two of sodium acrylate, acrylic acid, or methacrylic acid.

[0029] As a preferred embodiment of the present invention, the raw materials for preparing polymer solution A and polymer solution B each independently include 0.1 to 1 part of an initiator, for example, 0.1 part, 0.2 part, 0.3 part, 0.4 part, 0.5 part, 0.6 part, 0.7 part, 0.8 part, 0.9 part or 1 part, etc.

[0030] Preferably, the initiator is selected from any one or a combination of at least two of organic peroxide initiators, inorganic peroxide initiators, or redox initiators.

[0031] Preferably, the organic peroxide initiator is selected from benzoyl peroxide and / or dicumyl peroxide.

[0032] Preferably, the inorganic peroxide initiator is selected from any one or a combination of at least two of ammonium persulfate, sodium persulfate, or potassium persulfate.

[0033] Preferably, the redox initiator is selected from any one or a combination of ammonium persulfate and sodium sulfite, or a combination of ammonium persulfate and sodium bisulfite, or a combination of at least two of these.

[0034] Preferably, the raw materials for preparing polymer solution A and polymer solution B each independently include a solvent.

[0035] Preferably, the solvent is selected from any one or a combination of at least two of water, isopropanol, or butanediol.

[0036] As a preferred embodiment of the present invention, the solid content of the polymer solution A is 2%-10%, for example, it can be 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%, etc.

[0037] Preferably, the viscosity of the polymer solution A at 25°C is 10,000-50,000 cps, for example, it can be 10,000 cps, 15,000 cps, 20,000 cps, 25,000 cps, 30,000 cps, 35,000 cps, 40,000 cps, 45,000 cps or 50,000 cps, etc.

[0038] Preferably, the solid content of the polymer solution B is 20-30%, for example, it can be 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29% or 30%, etc.

[0039] Preferably, the viscosity of the polymer solution B at 25°C is 10,000-30,000 cps, for example, it can be 10,000 cps, 12,000 cps, 14,000 cps, 16,000 cps, 18,000 cps, 20,000 cps, 22,000 cps, 24,000 cps, 26,000 cps, 28,000 cps, or 30,000 cps, etc.

[0040] As a preferred embodiment of the present invention, based on the mass of the three-dimensional crosslinked aqueous polymer adhesive as 100%, the mass percentage of the polymer solution A is 1-80% (for example, it can be 1%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, or 80%, etc.), preferably 20-60%.

[0041] The polymer solution B has a mass percentage content of 20-99%, for example, it can be 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or 99%, etc.

[0042] In this invention, a high-performance three-dimensional cross-linked waterborne polymer adhesive was prepared by controlling the contents of polymer solution A and polymer solution B within a specific range. If the content of polymer solution A is too high, the prepared three-dimensional cross-linked waterborne polymer adhesive will have poor suspension and dispersion, low solid content, high brittleness, and poor flexibility; if the content of polymer solution A is too low, the prepared three-dimensional cross-linked waterborne polymer adhesive will have poor adhesion.

[0043] In a second aspect, the present invention provides a method for preparing a three-dimensional crosslinked aqueous polymer adhesive as described in the first aspect, the preparation method comprising the following steps:

[0044] Polymer solution A and polymer solution B are mixed to obtain the three-dimensional crosslinked aqueous polymer adhesive.

[0045] Preferably, the mixing temperature is 50-55°C, for example, 50°C, 51°C, 52°C, 53°C, 54°C, or 55°C.

[0046] Preferably, the mixing time is 60-120 minutes, for example, it can be 60 minutes, 70 minutes, 80 minutes, 90 minutes, 100 minutes, 110 minutes or 120 minutes.

[0047] Preferably, the mixing method is stirring, and the stirring speed is 100-300 rpm, for example, it can be 100 rpm, 120 rpm, 140 rpm, 160 rpm, 180 rpm, 200 rpm, 220 rpm, 240 rpm, 260 rpm, 280 rpm or 300 rpm, etc.

[0048] Preferably, the mixing process further includes a post-processing step.

[0049] Preferably, the post-processing method is sieving and discharging.

[0050] In this invention, the preparation method of the three-dimensional crosslinked aqueous polymer adhesive includes the following steps:

[0051] Under conditions of 50-55℃ and 100-300rpm, polymer solution A and polymer solution B are stirred and mixed for 60-120min, sieved, and discharged to obtain the three-dimensional crosslinked waterborne polymer binder.

[0052] As a preferred embodiment of the present invention, the polymer solution A is prepared by solution polymerization;

[0053] The polymer solution A is prepared by the following method, which includes the following steps:

[0054] (1) In a nitrogen atmosphere, the solvent, the monomer of formula 2, the monomer of formula 3 and the alkaline solution are mixed to obtain a mixed solution;

[0055] (2) The mixed solution obtained in step (1) is mixed with the monomer of formula 1 and the initiator, and reacted to obtain the polymerization product;

[0056] (3) After adding an alkaline solution to the polymer product obtained in step (2), the pressure is reduced under vacuum to obtain polymer solution A.

[0057] Preferably, the polymer solution B is prepared by soap-free emulsion polymerization;

[0058] The polymer solution B is prepared by the following method, which includes the following steps:

[0059] (A) In a nitrogen atmosphere, a solvent, monomer of formula 1, monomer of formula 2, monomer of formula 3 and alkaline solution are mixed to obtain a mixed solution;

[0060] (B) The mixed solution obtained in step (A) is mixed with an initiator, reacted, and vacuum depressurized to obtain the polymer solution B.

[0061] In this invention, polymer solution A is prepared by solution polymerization, and polymer solution B is prepared by soap-free emulsion polymerization, thus avoiding the adverse effects of emulsifiers on adhesive performance. Simultaneously, polymer molecular chains with different structures are prepared through different polymerization methods. A three-dimensional cross-linked structure is formed through the ionic bonding between the polymer molecular chains in polymer solutions A and B, resulting in an aqueous polymer adhesive with a three-dimensional cross-linked structure, good flexibility, and high adhesion.

[0062] As a preferred technical solution of the present invention, the mixing temperature in steps (1) and (A) is independently 20-30°C, for example, it can be 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C or 30°C, etc.

[0063] Preferably, the mixing temperature in steps (1) and (A) is independently 3-10h, for example, it can be 3h, 4h, 5h, 6h, 7h, 8h, 9h or 10h, etc.

[0064] Preferably, the mixing method in steps (1) and (A) is stirring, and the stirring rate is independently selected from 100-300 rpm, for example, 100 rpm, 120 rpm, 140 rpm, 160 rpm, 180 rpm, 200 rpm, 220 rpm, 240 rpm, 260 rpm, 280 rpm or 300 rpm.

[0065] Preferably, the alkaline substances in the alkaline solutions described in steps (1) and (A) are each independently selected from any one or a combination of at least two of sodium hydroxide, potassium hydroxide, lithium hydroxide, potassium carbonate, sodium carbonate, or sodium bicarbonate.

[0066] Preferably, the mass concentration of the alkaline solution in step (1) is 1-2%, for example, it can be 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9% or 2%, etc.

[0067] Preferably, the mass concentration of the alkaline solution in step (A) is 5-15%, for example, it can be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14% or 15%, etc.

[0068] Preferably, the pH of the mixed solution in steps (1) and (A) is independently 6-9, for example, it can be 6, 6.3, 6.6, 7, 7.2, 7.5, 8, 8.5 or 9, etc.

[0069] Preferably, in the mixed solution of step (1), the combined mass concentration of monomers of formula 2 and formula 3 is 15-30%, for example, it can be 15%, 16%, 18%, 20%, 22%, 24%, 25%, 27%, 28% or 30%, etc.

[0070] Preferably, in the mixed solution of step (A), the total mass concentration of monomers of formula 1, formula 2 and formula 3 is 10-30%, for example, it can be 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28% or 30%, etc.

[0071] Preferably, steps (1) and (A) further include a pretreatment step before mixing.

[0072] Preferably, the pretreatment method includes: deoxygenating the solvents in steps (1) and (A) at 20-30°C (e.g., 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, or 30°C, etc.) for 0.5-2 hours (e.g., 0.5 hours, 1 hour, 1.5 hours, or 2 hours, etc.).

[0073] It should be noted that the flow rate of nitrogen in steps (1) and (A) is 2000-4000 L / h, for example, it can be 2000 L / h, 2200 L / h, 2400 L / h, 2600 L / h, 2800 L / h, 3000 L / h, 3200 L / h, 3400 L / h, 3600 L / h, 3800 L / h or 4000 L / h, etc.

[0074] As a preferred embodiment of the present invention, the reactions described in steps (2) and (B) are carried out in a nitrogen atmosphere.

[0075] Preferably, the reaction temperatures in steps (2) and (B) are each independently 30-85°C, for example, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, or 85°C.

[0076] Preferably, the reaction times in steps (2) and (B) are each 5-10 hours, for example, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, or 10 hours.

[0077] It should be noted that the heating rate to reach the reaction temperature described in steps (2) and (B) is 1-2℃, for example, it can be 1℃, 1.2℃, 1.4℃, 1.6℃, 1.8℃ or 2℃, etc.

[0078] Preferably, the mass concentration of the alkaline solution in step (3) is 5-20%, for example, it can be 5%, 7%, 10%, 12%, 14%, 16%, 18% or 20%, etc.

[0079] It should be noted that the amount of alkaline solution added in step (3) is: after adding alkaline solution, the pH of the polymerization product reaction system is adjusted to 7-7.5 (for example, it can be 7, 7.1, 7.2, 7.3, 7.4 or 7.5, etc.).

[0080] Preferably, the vacuum decompression temperatures in steps (3) and (B) are each independently 50-55°C, for example, 50°C, 51°C, 52°C, 53°C, 54°C, or 55°C.

[0081] Preferably, the vacuum degree of vacuum reduction in steps (3) and (B) is ≤0.1MPa, for example, it can be 0.09MPa, 0.08MPa, 0.07MPa, 0.06MPa or 0.05MPa, etc.

[0082] In this invention, unreacted monomers are removed by vacuum decompression.

[0083] Preferably, the vacuum decompression steps (3) and (B) further include a post-processing step.

[0084] Preferably, the post-processing method includes filtration and discharge.

[0085] Preferably, the mesh size of the sieve used for filtration is 150-300 mesh, for example, it can be 150 mesh, 180 mesh, 200 mesh, 220 mesh, 250 mesh, 270 mesh or 300 mesh, etc.

[0086] As a preferred embodiment of the present invention, the polymer solution A is prepared by the following method, which includes the following steps:

[0087] (1) Under the conditions of 20℃, rotation speed of 100-300rpm and nitrogen flow rate of 2000-4000L / h, the solvent is deoxygenated for 0.5-2h, and then the monomer of formula 2, the monomer of formula 3 and an alkaline solution with a mass concentration of 1-2% are added and stirred for 3-10h to obtain a mixed solution with a pH of 6-9; in the mixed solution, the mass concentration of the monomer of formula 2 and the monomer of formula 3 is 15-30%;

[0088] (2) In a nitrogen atmosphere, the mixed solution obtained in step (1) is heated to 30-85℃ at a heating rate of 1-2℃ / min, and the monomer of formula 1 and the initiator are added to it. The reaction is carried out for 5-10 hours to obtain the polymerization product.

[0089] (3) Add an alkaline solution with a mass concentration of 5-20% to the polymer product obtained in step (2) until the pH is 7-7.5. Then, at 50-55°C, reduce the vacuum to ≤0.1MPa to remove unreacted monomers of formula 1, formula 2 and formula 3. Filter the product through a 150-300 mesh sieve and discharge it to obtain the polymer solution A.

[0090] In this invention, the polymer solution B is prepared by the following method, which includes the following steps:

[0091] (A) Under the conditions of 20℃, rotation speed of 100-300rpm, and nitrogen flow rate of 2000-4000L / h, the solvent is deoxygenated for 0.5-2h, and then monomers of formula 1, formula 2, and formula 3 and an alkaline solution with a mass concentration of 5-15% are added and stirred for 3-10h to obtain a mixed solution with a pH of 6-9; in the mixed solution, the mass concentration of monomers of formula 1, formula 2, and formula 3 is 10-30%;

[0092] (B) In a nitrogen atmosphere, the mixed solution obtained in step (1) is heated to 30-85°C at a heating rate of 1-2°C / min. An initiator is added to it, and after reacting for 5-10 hours, the vacuum is reduced to ≤0.1MPa at 50-55°C. Unreacted monomers of formula 1, formula 2, and formula 3 are removed, and the mixture is filtered through a 150-300 mesh sieve and discharged to obtain the polymer solution B.

[0093] Thirdly, the present invention provides the application of the three-dimensional cross-linked aqueous polymer binder as described in the first aspect in a lithium-ion battery, the lithium-ion battery comprising electrode sheets.

[0094] The raw materials for preparing the electrode sheet include the three-dimensional cross-linked aqueous polymer binder as described in the first aspect.

[0095] Preferably, the raw materials for preparing the electrode sheet include a negative electrode material, conductive carbon black, and a three-dimensional cross-linked aqueous polymer binder as described in the first aspect.

[0096] Preferably, the negative electrode material is selected from any one of artificial graphite, natural graphite, activated carbon, and silicon-based composite negative electrode materials.

[0097] Compared with the prior art, the present invention has the following beneficial effects:

[0098] In this invention, by designing the raw materials and content of polymer solutions A and B, and controlling the content of polymer solutions A and B within a specific range, a three-dimensional cross-linked aqueous polymer binder is prepared. This binder exhibits good flexibility and high adhesion, with a peel strength of 5.89–7.66 N / mm. The lithium-ion battery prepared from this binder exhibits good electrical performance and high-temperature storage properties. Its initial coulombic efficiency is 88.07–89.42%, its 0.33C discharge specific capacity is 137.23–143.76 mAh / g, its full-charge rebound is 18.6–21.7%, its high-temperature discharge is 99.27–100.86%, its discharge DCR at 50% SOC is 30.06–31.78 mΩ, and after storage at 60°C for 7 days, its capacity retention rate is 95.98–96.58%, its capacity recovery rate is 96.06–97.70%, and its volume change rate is 0.39–0.60%. Detailed Implementation

[0099] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0100] Example 1

[0101] This embodiment provides a three-dimensional cross-linked aqueous polymer adhesive and its preparation method. The three-dimensional cross-linked polymer adhesive comprises a polymer solution A with a mass percentage of 40% and a polymer solution B with a mass percentage of 60%, based on a mass percentage of 100%.

[0102] The raw materials for preparing the polymer solution A include the following components in parts by weight: 55 parts acrylic acid, 5 parts N,N-diethylacrylamide, 40 parts acrylonitrile, and 0.5 parts benzoyl peroxide.

[0103] The raw materials for preparing the polymer solution B include the following components in parts by weight: 70 parts acrylic acid, 10 parts acrylamide, 20 parts acrylonitrile, and 0.5 parts benzoyl peroxide.

[0104] The preparation method of polymer solution A is as follows:

[0105] (1) At 20℃, 100rpm, and 2000L / h nitrogen flow rate, 255 parts of water were added to the reactor. After deoxygenation treatment for 0.5 to 2h, N,N-diethylacrylamide, acrylonitrile and sodium hydroxide solution with a mass concentration of 1.5% were added and stirred for 8h to obtain a mixed solution with a pH of 7.0.

[0106] (2) In a nitrogen atmosphere, the mixed solution obtained in step (1) was heated to 55°C at a heating rate of 1°C / min. Acrylic acid and benzoyl peroxide solution with a mass fraction of 10% were added to it and reacted for 6 hours to obtain the polymer product.

[0107] (3) Add a 20% sodium hydroxide solution to the polymer product obtained in step (2) to form a viscous water-soluble binder with a system pH of 7.2. Then, at 50°C, reduce the vacuum to ≤0.1MPa to remove the monomer. After filtering through a 300-mesh sieve, the polymer solution A is obtained.

[0108] The preparation method of the polymer solution B is as follows:

[0109] (A) At 20℃, 100rpm, and 2000L / h nitrogen flow rate, 350 parts of water were added to the reactor and deoxygenated for 1.5h. Then, acrylic acid, acrylamide, and acrylonitrile were added and stirred for 5h to obtain a mixed solution with pH 7.0.

[0110] (B) In a nitrogen atmosphere, the mixed solution obtained in step (1) is heated to 55°C at a heating rate of 1°C / min. 0.5 parts of benzoyl peroxide solution with a mass fraction of 10% are added to it. After reacting for 6 hours, the vacuum is reduced to ≤0.1MPa at 50°C to remove unreacted monomers. The solution is then filtered through a 300-mesh sieve and discharged to obtain the polymer solution B.

[0111] The preparation method of the above-mentioned three-dimensional crosslinked aqueous polymer binder is as follows:

[0112] At 55°C and 200 rpm, polymer solution A and polymer solution B were stirred and mixed for 120 min, then sieved and discharged to obtain the three-dimensional crosslinked waterborne polymer binder.

[0113] Example 2

[0114] This embodiment provides a three-dimensional cross-linked aqueous polymer adhesive and its preparation method. The three-dimensional cross-linked polymer adhesive comprises a polymer solution A with a mass percentage of 40% and a polymer solution B with a mass percentage of 60%, based on a mass percentage of 100%.

[0115] The raw materials for preparing the polymer solution A include the following components in parts by weight: 5 parts methacrylonitrile, 30 parts N,N-diethylacrylamide, 60 parts sodium acrylate, and 0.2 parts ammonium persulfate.

[0116] The raw materials for preparing the polymer solution B include the following components in parts by weight: 10 parts methacrylonitrile, 1 part 2-acrylamide-2-phenylethanesulfonic acid, 90 parts methacrylic acid, and 0.3 parts ammonium persulfate.

[0117] The preparation method of polymer solution A is as follows:

[0118] (1) At 20℃, 100 rpm, and 2000 L / h of nitrogen, 105 parts of isopropanol were added to the reactor. After deoxygenation treatment for 2 h, N,N-diethylacrylamide, sodium acrylate, and 2% sodium hydroxide solution were added. The mixture was stirred and mixed for 10 h to obtain a mixed solution with pH 6. The total mass concentration of the monomers of Formula 2 and Formula 3 in the mixed solution was 30%.

[0119] (2) In a nitrogen atmosphere, the mixed solution obtained in step (1) was heated to 85°C at a heating rate of 2°C / min, and methacrylonitrile and ammonium persulfate solution with a mass concentration of 10% were added to it. The reaction was carried out for 5 hours to obtain the polymerization product.

[0120] (3) Add a 20% sodium hydroxide solution to the polymer product obtained in step (2) until the pH is 7. Then, at 55°C, reduce the pressure under vacuum to ≤0.1MPa to remove unreacted monomers. Filter the solution through a 150-mesh sieve and discharge it to obtain the polymer solution A.

[0121] The preparation method of the polymer solution B is as follows:

[0122] (A) At 20°C, 100 rpm, and 2000 L / h of nitrogen, 235 parts of isopropanol were added to a reactor. After deoxygenation treatment for 2 h, methacrylonitrile, 2-acrylamide-2-phenylethanesulfonic acid, methacrylic acid, and a 5% sodium hydroxide solution were added. The mixture was stirred for 3 h to obtain a mixed solution with a pH of 9. The total mass concentration of the monomers of Formula 1, Formula 2, and Formula 3 in the mixed solution was 30%.

[0123] (B) In a nitrogen atmosphere, the mixed solution obtained in step (1) is heated to 85°C at a heating rate of 2°C / min. A 10% ammonium persulfate solution is added to it. After reacting for 5 hours, the pressure is reduced to ≤0.1 MPa at 55°C to remove unreacted monomers. The solution is then filtered through a 150-mesh sieve and discharged to obtain the polymer solution B.

[0124] The preparation method of the above-mentioned three-dimensional crosslinked aqueous polymer binder is as follows:

[0125] Under conditions of 50°C and 100 rpm, polymer solution A and polymer solution B are stirred and mixed for 120 min, then sieved and discharged to obtain the three-dimensional crosslinked waterborne polymer binder.

[0126] Example 3

[0127] This embodiment provides a three-dimensional cross-linked aqueous polymer adhesive and its preparation method. The three-dimensional cross-linked polymer adhesive comprises a polymer solution A with a mass percentage of 40% and a polymer solution B with a mass percentage of 60%, based on a mass percentage of 100%.

[0128] The raw materials for preparing the polymer solution A include the following components in parts by weight: 80 parts methacrylonitrile, 10 parts 2-acrylamide-2-phenylethanesulfonic acid, 10 parts acrylic acid, and 0.4 parts sodium persulfate.

[0129] The raw materials for preparing the polymer solution B include the following components in parts by weight: 100 parts acrylonitrile, 1 part acrylamide, 10 parts methacrylic acid, and 0.6 parts sodium persulfate.

[0130] The preparation method of polymer solution A is as follows:

[0131] (1) Under the conditions of 20℃, 300rpm rotation speed and nitrogen flow rate of 4000L / h, 115 parts of butanediol were added to the reactor, and after deoxygenation treatment for 0.5h, 2-acrylamide-2-phenylethanesulfonic acid, acrylic acid and potassium hydroxide solution with a mass concentration of 1% were added to the reactor and stirred for 3h to obtain a mixed solution with a pH of 9; in the mixed solution, the mass concentration of monomer of formula 2 and monomer of formula 3 was 15%;

[0132] (2) In a nitrogen atmosphere, the mixed solution obtained in step (1) is heated to 30°C at a heating rate of 1°C / min, and methacrylonitrile and sodium persulfate solution with a mass concentration of 10% are added to it. The reaction is carried out for 10 hours to obtain the polymerization product.

[0133] (3) Add a 5% potassium hydroxide solution to the polymer product obtained in step (2) until the pH is 7.5. Then, at 50°C, reduce the pressure under vacuum to ≤0.1MPa to remove unreacted monomers. Filter the solution through a 300-mesh sieve and discharge it to obtain the polymer solution A.

[0134] The preparation method of the polymer solution B is as follows:

[0135] (A) At 20°C, 300 rpm, and 4000 L / h of nitrogen, 1000 parts of butanediol were added to a reactor. After deoxygenation treatment for 0.5 h, acrylonitrile, acrylamide, methacrylic acid, and a 15% potassium hydroxide solution were added. The mixture was stirred and mixed for 10 h to obtain a mixed solution with a pH of 6. The total mass concentration of the monomers of Formula 1, Formula 2, and Formula 3 in the mixed solution was 10%.

[0136] (B) In a nitrogen atmosphere, the mixed solution obtained in step (1) is heated to 30°C at a heating rate of 1°C / min. A sodium persulfate solution with a mass concentration of 10% is added to it. After reacting for 10 hours, the solution is vacuumed to a vacuum degree of ≤0.1MPa at 50°C to remove unreacted monomers. The solution is then filtered through a 300-mesh sieve and discharged to obtain the polymer solution B.

[0137] The preparation method of the above-mentioned three-dimensional crosslinked aqueous polymer binder is as follows:

[0138] Under conditions of 55℃ and 300rpm, polymer solution A and polymer solution B are stirred and mixed for 60min, then sieved and discharged to obtain the three-dimensional crosslinked waterborne polymer binder.

[0139] Example 4

[0140] This embodiment provides a three-dimensional cross-linked aqueous polymer adhesive and its preparation method. The three-dimensional cross-linked polymer adhesive comprises a polymer solution A with a mass percentage of 40% and a polymer solution B with a mass percentage of 60%, based on a mass percentage of 100%.

[0141] The raw materials for preparing the polymer solution A include the following components in parts by weight: 70 parts acrylonitrile, 1 part acrylamide, 30 parts sodium acrylate, and 1 part sodium persulfate.

[0142] The raw materials for preparing the polymer solution B include the following components in parts by weight: 50 parts acrylonitrile, 15 parts N,N-diethylacrylamide, 35 parts acrylic acid, and 0.7 parts sodium persulfate.

[0143] The preparation method of polymer solution A is as follows:

[0144] (1) At 20℃, 200rpm and 3000L / h nitrogen flow rate, 124 parts of water were added to the reactor. After deoxygenation treatment for 1h, acrylamide, sodium acrylate and sodium hydroxide solution with a mass concentration of 1.5% were added and stirred for 7h to obtain a mixed solution with pH of 8.

[0145] (2) In a nitrogen atmosphere, the mixed solution obtained in step (1) was heated to 75°C at a heating rate of 1°C / min, and acrylonitrile and sodium persulfate solution with a mass concentration of 10% were added to it. The reaction was carried out for 7 hours to obtain the polymer product.

[0146] (3) Add a sodium hydroxide solution with a mass concentration of 5-20% to the polymer product obtained in step (2) until the pH is 7.2. Then, at 52°C, reduce the pressure under vacuum to a vacuum degree of ≤0.1MPa to remove unreacted monomers. Filter the solution through a 200-mesh sieve and discharge it to obtain the polymer solution A.

[0147] The preparation method of the polymer solution B is as follows:

[0148] (A) At 20℃, 200rpm, and 2400L / h nitrogen flow rate, 400 parts of water were added to the reactor. After deoxygenation treatment for 1h, acrylonitrile, N,N-diethylacrylamide, acrylic acid and 12% potassium hydroxide solution were added to the reactor. The mixture was stirred and mixed for 8h to obtain a mixed solution with pH 7.

[0149] (B) In a nitrogen atmosphere, the mixed solution obtained in step (1) is heated to 75°C at a heating rate of 1°C / min. A sodium persulfate solution with a mass concentration of 10% is added to it. After reacting for 8 hours, the solution is vacuumed to a vacuum degree of ≤0.1MPa at 54°C to remove unreacted monomers. The solution is then filtered through a 200-mesh sieve and discharged to obtain the polymer solution B.

[0150] The preparation method of the above-mentioned three-dimensional crosslinked aqueous polymer binder is as follows:

[0151] Under conditions of 52℃ and 200rpm, polymer solution A and polymer solution B are stirred and mixed for 100min, sieved, and discharged to obtain the three-dimensional cross-linked waterborne polymer binder.

[0152] Example 5

[0153] This embodiment provides a three-dimensional crosslinked waterborne polymer adhesive, which differs from Embodiment 1 only in that the mass percentage of polymer solution A in the three-dimensional crosslinked waterborne polymer adhesive is 20% and the mass percentage of polymer solution B is 80%, while other conditions are the same as in Embodiment 1.

[0154] Example 6

[0155] This embodiment provides a three-dimensional crosslinked waterborne polymer adhesive, which differs from Embodiment 1 only in that the mass percentage of polymer solution A in the three-dimensional crosslinked waterborne polymer adhesive is 60% and the mass percentage of polymer solution B is 40%, while other conditions are the same as in Embodiment 1.

[0156] Example 7

[0157] This embodiment provides a three-dimensional crosslinked waterborne polymer adhesive, which differs from Embodiment 1 only in that the polymer solution A has a mass percentage of 5% and the polymer solution B has a mass percentage of 95% in the three-dimensional crosslinked waterborne polymer adhesive, while other conditions are the same as in Embodiment 1.

[0158] Example 8

[0159] This embodiment provides a three-dimensional crosslinked aqueous polymer adhesive, which differs from Embodiment 1 only in that the mass percentage of polymer solution A in the three-dimensional crosslinked aqueous polymer adhesive is 80% and the mass percentage of polymer solution B is 20%, while other conditions are the same as in Embodiment 1.

[0160] Example 9

[0161] This embodiment provides a three-dimensional crosslinked aqueous polymer adhesive, which differs from Example 1 only in that the raw materials for preparing polymer solution A contain 5 parts by weight of acrylic acid, while other conditions are the same as in Example 1.

[0162] Example 10

[0163] This embodiment provides a three-dimensional crosslinked aqueous polymer adhesive, which differs from Example 1 only in that the raw materials for preparing polymer solution A contain 80 parts by weight of acrylic acid, while other conditions are the same as in Example 1.

[0164] Example 11

[0165] This embodiment provides a three-dimensional crosslinked aqueous polymer adhesive, which differs from Example 1 only in that the weight of N,N-diethylacrylamide in the raw materials for preparing polymer solution A is 1 part, while other conditions are the same as in Example 1.

[0166] Example 12

[0167] This embodiment provides a three-dimensional crosslinked aqueous polymer adhesive, which differs from Example 1 only in that the weight of N,N-diethylacrylamide in the raw materials for preparing polymer solution A is 30 parts, while other conditions are the same as in Example 1.

[0168] Comparative Example 1

[0169] This comparative example provides a three-dimensional crosslinked aqueous polymer adhesive, which differs from Example 1 only in that the raw materials for preparing polymer solution A contain 2 parts by weight of acrylic acid, while other conditions are the same as in Example 1.

[0170] Comparative Example 2

[0171] This comparative example provides a three-dimensional crosslinked aqueous polymer adhesive, which differs from Example 1 only in that the raw materials for preparing polymer solution A contain 90 parts by weight of acrylic acid, while other conditions are the same as in Example 1.

[0172] Comparative Example 3

[0173] This comparative example provides a three-dimensional crosslinked aqueous polymer adhesive, which differs from Example 1 only in that the raw materials for preparing polymer solution A do not contain N,N-diethylacrylamide, while the other conditions are the same as in Example 1.

[0174] Comparative Example 4

[0175] This comparative example provides a three-dimensional crosslinked aqueous polymer adhesive, which differs from Example 1 only in that the weight of N,N-diethylacrylamide in the raw materials for preparing polymer solution A is 40 parts, while other conditions are the same as in Example 1.

[0176] Comparative Example 5

[0177] This comparative example provides an aqueous polymer binder, which differs from Example 1 only in that the aqueous polymer binder is polymer solution A, and the raw materials and preparation method of polymer solution A are the same as those in Example 1.

[0178] Comparative Example 6

[0179] This comparative example provides an aqueous polymer binder, which differs from Example 1 only in that the aqueous polymer binder is polymer solution B, and the raw materials and preparation method of polymer solution B are the same as those in Example 1.

[0180] Comparative Example 7

[0181] This comparative example provides an adhesive that uses commercially available battery-grade sodium carboxymethyl cellulose (CMC) and styrene-butadiene rubber latex (SBR).

[0182] The negative electrode sheets for lithium-ion batteries were prepared using the binders provided in the above embodiments and comparative examples, respectively. The negative electrode sheet material comprises the following components in mass percentage: natural graphite, conductive carbon black and binder at a mass fraction of 95.5 wt%, conductive carbon black at 2.0 wt%, and an aqueous binder for lithium-ion batteries at a mass fraction of 2.5 wt% based on solid content.

[0183] The method for preparing the negative electrode sheet is as follows:

[0184] Based on the total solid content of the aforementioned negative electrode material being 45%, 65% deionized water was added and mixed thoroughly to obtain a negative electrode slurry. After passing through a 100-mesh sieve, the negative electrode slurry was coated onto a 10μm thick copper foil serving as the current collector. The foil was then dried in a 120℃ oven for 5 minutes and allowed to cool naturally to room temperature. The slurry was then... 4 The negative electrode sheet is obtained by rolling under a unit length load of N / m.

[0185] A lithium-ion battery was fabricated using lithium iron phosphate as the positive electrode, a mixed solvent of ethylene carbonate EC: ethyl methyl carbonate EMC: diethyl carbonate DEC in a mass ratio of 3:2:5 containing 1M LiPF6 as the electrolyte, and PE / PP material as the separator. The design information of the lithium-ion battery is shown in Table 1 below.

[0186] Table 1

[0187]

[0188] The performance of the negative electrode sheet and lithium-ion battery prepared with the binder provided in the above embodiments and comparative examples was tested. The specific test methods are as follows:

[0189] First coulombic efficiency: The lithium-ion batteries prepared with the binders provided in the above examples and comparative examples were subjected to charge-discharge cycles at 25°C, a voltage range of 2.5 to 4.2V, and 0.5C, and the first coulombic efficiency of the charge-discharge cycles was tested using the constant current method.

[0190] 0.33C discharge capacity: The ratio of the capacitance that the active material in the positive electrode material of the battery cell can receive to the mass of the active material.

[0191] Full-charge rebound: The original thickness L1 (μm) of the negative electrode was tested, and the electrode was assembled into a lithium-ion battery. After capacity testing, the cell was dissected at full charge to measure the electrode thickness L2 (μm) and calculate the electrode rebound rate.

[0192] Electrode rebound rate = (L2-L1) / (L1-copper foil thickness)×100%.

[0193] High-temperature discharge: The above lithium-ion batteries were placed directly in an oven at 60°C and charged and discharged at 0.5C within a voltage range of 2.5 to 4.2V to measure their high-temperature discharge performance.

[0194] Peel strength: The electrode sheet prepared by the adhesive provided in the above examples and comparative examples was cut into strips of 20cm×2.5cm. A 1mm thick steel plate was bonded to the current collector side with double-sided adhesive, and transparent tape was pasted on the coating layer side. The electrode sheet was peeled in the 180° direction at a speed of 100mm / min using a tensile testing machine, and the peel stress was measured.

[0195] Discharge DCR at 50% SOC: The ratio of the discharge capacity to the rated capacity of a fully charged battery at 50% SOC discharged at a rate of 0.5C for 1 hour is the SOC, expressed as a percentage. Room temperature DCR test: The battery is discharged at a high rate to determine the cell's power capability: discharged at 4C current for 30 seconds (10 points per second). DCR discharge (I1, t1) = |V0 - V1| / I1.

[0196] Where V0 is the sampling voltage at the start of the discharge after the static discharge ends, V1 is the voltage at the end of the discharge, t1 is the discharge duration, and I1 is the discharge current value.

[0197] 60℃ / 7D Capacity Retention Rate: The above lithium-ion batteries were placed directly in an oven at 60℃, charged at 0.5C within a voltage range of 2.5~4.2V, and then left for 7 days before the capacity retention rate was measured.

[0198] 60℃ / 7D Capacity Recovery Rate: The battery is first charged to standard, then stored under certain conditions for 28 days. After that, it is discharged according to the standard discharge rate to obtain the capacity C1. After standing for 30 minutes, standard charge and discharge are started to obtain the discharge capacity C2. The capacity recovery rate = C1 / C2.

[0199] 60℃ / 7D Volume Change Rate: The lithium-ion battery was charged and discharged at 25℃, within a voltage range of 2.5~4.2V, and at 0.5C. The coulombic efficiency of the first charge and discharge cycle and the coulombic efficiency and capacity retention rate after 50 cycles were tested using the constant current method. After 50 charge and discharge cycles, the ratio of the increase in electrode thickness to the electrode thickness before charge and discharge in the lithium-intercalated state of the electrode sheet was recorded as the electrode expansion rate.

[0200] The performance test results of the negative electrode sheets and lithium-ion batteries prepared using the binders provided in the above embodiments and comparative examples are shown in Tables 2 and 3 below:

[0201] Table 2

[0202]

[0203]

[0204] Table 3

[0205]

[0206]

[0207] As shown in Tables 2 and 3, the three-dimensional cross-linked aqueous polymer binder prepared in this invention, by designing the raw materials and content of polymer solutions A and B, and controlling the content of polymer solutions A and B within a specific range, exhibits good flexibility and high adhesion, with a peel strength of 5.89–7.66 N / mm. The resulting lithium-ion battery demonstrates good electrical performance and high-temperature storage capability, with an initial coulombic efficiency of 88.07–… The specific capacity at 0.33C discharge is 137.23–143.76 mAh / g, the full charge rebound is 18.6–21.7%, the high-temperature discharge is 99.27–100.86%, the discharge DCR at 50% SOC is 30.06–31.78 mΩ, and after storage at 60℃ for 7 days, the capacity retention rate is 95.22–96.58%, the capacity recovery rate is 96.06–97.70%, and the volume change rate is 0.39–0.60%.

[0208] Compared with Example 1, if the content of monomer of Formula 1 in polymer solution A is too low (Comparative Example 1) or too high (Comparative Example 2), or if the content of monomer of Formula 2 in polymer solution A is too low (Comparative Example 3) or too high (Comparative Example 4), the uniform adhesion of the prepared three-dimensional cross-linked aqueous polymer binder is poor, and the overall performance of the lithium-ion battery prepared thereby is poor.

[0209] Compared to Example 1, the overall performance of the prepared three-dimensional crosslinked aqueous polymer binder is poor when polymer solution A is used as the binder (Comparative Example 5) or polymer solution B is used as the binder (Comparative Example 6). The performance of the prepared lithium-ion battery is also poor when using a binder provided by the prior art (Comparative Example 7).

[0210] In summary, by designing the raw materials and content of polymer solutions A and B, and controlling the content of polymer solutions A and B within a specific range, the three-dimensional cross-linked aqueous polymer binder prepared in this invention has good flexibility and high adhesion. The lithium-ion battery prepared in this way has excellent comprehensive performance.

[0211] The applicant declares that the detailed process flow of this invention is illustrated by the above embodiments, but this invention is not limited to the above detailed process flow, that is, it does not mean that this invention must rely on the above detailed process flow to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials for the product of this invention, addition of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of this invention.

Claims

1. A three-dimensional crosslinked aqueous polymer binder, characterized by, The three-dimensional cross-linked polymer binder comprises polymer solution A and polymer solution B; The polymer solution A and polymer solution B form a three-dimensional cross-linked through-network structure through ionic bonding; Based on the mass of the three-dimensional cross-linked aqueous polymer adhesive as 100%, the mass percentage of polymer solution A is 20-60%, and the mass percentage of polymer solution B is 40-80%. The polymer solution A is prepared by solution polymerization, and its raw materials include the following components in parts by weight: 5-80 parts of monomer of formula 1, 1-30 parts of monomer of formula 2 and 10-60 parts of monomer of formula 3. The polymer solution B is prepared by soap-free emulsion polymerization, and its raw materials include the following components in parts by weight: 10-100 parts of monomer of formula 1, 1-30 parts of monomer of formula 2 and 10-90 parts of monomer of formula 3. The monomer of Formula 1 is selected from methacrylonitrile and / or acrylonitrile; The monomer of Formula 2 is selected from any one or a combination of at least two of N,N-diethylacrylamide, acrylamide, or 2-acrylamide-2-phenylethanesulfonic acid. The monomer of Formula 3 is selected from any one or a combination of at least two of sodium acrylate, acrylic acid, or methacrylic acid.

2. The three-dimensional crosslinked aqueous polymer adhesive according to claim 1, characterized in that, The raw materials for preparing polymer solution A and polymer solution B each independently include 0.1 to 1 part of initiator.

3. The three-dimensional crosslinked aqueous polymer adhesive according to claim 2, characterized in that, The initiator is selected from any one or a combination of at least two of the following: organic peroxide initiators, inorganic peroxide initiators, or redox initiators.

4. The three-dimensional crosslinked aqueous polymer adhesive according to claim 1, characterized in that, The raw materials for preparing polymer solution A and polymer solution B each independently include a solvent.

5. The three-dimensional crosslinked aqueous polymer adhesive according to claim 4, characterized in that, The solvent is selected from any one or a combination of at least two of water, isopropanol, or butanediol.

6. The three-dimensional crosslinked aqueous polymer adhesive according to any one of claims 1-5, characterized in that, The solid content of the polymer solution A is 2%-10%.

7. The three-dimensional crosslinked aqueous polymer adhesive according to any one of claims 1-5, characterized in that, The viscosity of the polymer solution A at 25°C is 10,000-50,000 cps.

8. The three-dimensional crosslinked aqueous polymer adhesive according to any one of claims 1-5, characterized in that, The solid content of the polymer solution B is 20-30%.

9. The three-dimensional crosslinked aqueous polymer adhesive according to any one of claims 1-5, characterized in that, The viscosity of the polymer solution B at 25°C is 10,000-30,000 cps.

10. A method for preparing a three-dimensional crosslinked aqueous polymer adhesive as described in any one of claims 1-9, characterized in that, The preparation method includes the following steps: Polymer solution A and polymer solution B are mixed to obtain the three-dimensional crosslinked aqueous polymer adhesive.

11. The preparation method according to claim 10, characterized in that, The mixing temperature is 50-55℃.

12. The preparation method according to claim 10, characterized in that, The mixing time is 60-120 min.

13. The preparation method according to claim 10, characterized in that, The mixing method is stirring, and the stirring speed is 100-300 rpm.

14. The preparation method according to claim 10, characterized in that, The polymer solution A was prepared by solution polymerization; The polymer solution A is prepared by the following method, which includes the following steps: (1) In a nitrogen atmosphere, the solvent, monomer of formula 2, monomer of formula 3 and alkaline solution are mixed to obtain a mixed solution; (2) The mixed solution obtained in step (1) is mixed with the monomer of formula 1 and the initiator, and reacted to obtain the polymerization product; (3) After adding an alkaline solution to the polymer product obtained in step (2), the pressure is reduced under vacuum to obtain polymer solution A.

15. The preparation method according to claim 10, characterized in that, The polymer solution B was prepared by soap-free emulsion polymerization. The polymer solution B is prepared by the following method, which includes the following steps: (A) In a nitrogen atmosphere, a solvent, monomer of formula 1, monomer of formula 2, monomer of formula 3 and alkaline solution are mixed to obtain a mixed solution; (B) The mixed solution obtained in step (A) is mixed with an initiator, reacted, and vacuum depressurized to obtain the polymer solution B.

16. The preparation method according to claim 14 or 15, characterized in that, The mixing temperatures described in steps (1) and (A) are each independently 20-30°C.

17. The preparation method according to claim 14 or 15, characterized in that, The mixing time described in steps (1) and (A) is 3-10 h each independently.

18. The preparation method according to claim 14 or 15, characterized in that, The mixing method described in steps (1) and (A) is stirring, and the stirring rate is independently selected from 100-300 rpm.

19. The preparation method according to claim 14 or 15, characterized in that, The alkaline substances in the alkaline solutions described in steps (1) and (A) are each independently selected from any one or at least a combination of two of sodium hydroxide, potassium hydroxide, lithium hydroxide, potassium carbonate, sodium carbonate, or sodium bicarbonate.

20. The preparation method according to claim 14, characterized in that, The mass concentration of the alkaline solution in step (1) is 1-2%.

21. The preparation method according to claim 15, characterized in that, The mass concentration of the alkaline solution in step (A) is 5-15%.

22. The preparation method according to claim 14 or 15, characterized in that, The pH of the mixed solutions described in steps (1) and (A) is independently 6-9.

23. The preparation method according to claim 14, characterized in that, In the mixed solution described in step (1), the combined mass concentration of monomers of formula 2 and formula 3 is 15-30%.

24. The preparation method according to claim 15, characterized in that, In the mixed solution described in step (A), the sum of the mass concentrations of monomers of formula 1, formula 2 and formula 3 is 10-30%.

25. The preparation method according to claim 14 or 15, characterized in that, The mixing process described in steps (1) and (A) also includes a pretreatment step.

26. The preparation method according to claim 25, characterized in that, The pretreatment method includes: deoxygenating the solvents of steps (1) and (A) at 20-30°C for 0.5-2 h.

27. The preparation method according to claim 14 or 15, characterized in that, The reactions described in steps (2) and (B) are carried out in a nitrogen atmosphere.

28. The preparation method according to claim 14 or 15, characterized in that, The temperatures of the reactions described in steps (2) and (B) are each 30-85°C.

29. The preparation method according to claim 14 or 15, characterized in that, The reaction times described in steps (2) and (B) are each 5-10 h independently.

30. The preparation method according to claim 14, characterized in that, The mass concentration of the alkaline solution in step (3) is 5-20%.

31. The preparation method according to claim 14 or 15, characterized in that, The vacuum decompression temperatures described in steps (3) and (B) are each 50-55°C.

32. The preparation method according to claim 14 or 15, characterized in that, The vacuum degree of vacuum reduction in steps (3) and (B) is ≤0.1 MPa, respectively.

33. The application of a three-dimensional crosslinked aqueous polymer binder as described in any one of claims 1-9 in a lithium-ion battery, characterized in that, The lithium-ion battery includes electrode plates; The raw materials for preparing the electrode sheet include the three-dimensional cross-linked aqueous polymer binder as described in any one of claims 1-9.

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