Method for treating polyvinyl alcohol modified high-wettability diaphragm for lithium ion battery through electron beam irradiation

Abstract

The invention discloses a method for treating a polyvinyl alcohol modified high-wettability diaphragm for a lithium ion battery through electron beam irradiation. The method mainly comprises two parts, namely preparation of a grafted monomer solution and electron beam irradiation treatment. The method comprises the following specific operation steps: (1) dissolving polyvinyl alcohol in deionized water to prepare a grafted monomer solution; (2) immersing the polypropylene diaphragm which is subjected to ultrasonic cleaning and fully dried into the grafting monomer solution, and uniformly soaking; and (3) carrying out electron beam irradiation treatment on the soaked diaphragm and the grafted monomer solution, then cleaning with deionized water, and drying. According to the preparation method disclosed by the invention, collaborative optimization of surface chemical modification and porous structure integrity is realized by grafting polyvinyl alcohol and accurately controlling the irradiation dose, and the diaphragm with high wettability and high thermal stability is designed under the combined action of a polar functional group contained in a monomer and an active site obtained by irradiation; and a new technical approach is provided for developing a high-performance lithium ion battery diaphragm.

Description

Technical Field

[0001] The present application relates to the field of lithium - ion batteries, and particularly to a method for treating a polyethylene - alcohol - modified highly wettable separator for lithium - ion batteries by electron beam irradiation. Background Art

[0002] Promoting the development of clean and efficient renewable energy has become a key path to solve resource and environmental problems. Among many technical solutions, electrochemical energy storage has become one of the solutions that have received much attention because of its high efficiency, wide applicability, and significant role in reducing greenhouse gas emissions and environmental pollution. As a way of energy storage that realizes the mutual conversion of electrical energy and chemical energy through chemical reactions, electrochemical energy storage technology is being rapidly promoted globally. Among them, lithium - ion batteries have occupied a dominant position in many fields with their excellent performance and show broad application prospects.

[0003] Lithium - ion batteries mainly consist of electrode materials, electrolyte, separator, and shell. Among them, the separator, as a key component, is responsible for separating the positive and negative electrodes to prevent short - circuit, and at the same time allowing ions in the electrolyte to pass through. An ideal separator should have excellent thermal stability and electrochemical stability, a suitable pore structure, good mechanical properties, and excellent wettability to ensure the efficient operation, long life, and high safety of the battery. Currently, commercially available separators on the market are mainly made of polyolefin materials, but they have two significant disadvantages: one is the poor electrolyte affinity caused by surface hydrophobicity, which limits the ion transport rate; the other is the insufficient thermal stability, especially the high thermal shrinkage rate, which increases the risk of thermal runaway and thus reduces the safety of the battery. Therefore, modifying and improving commercially available polyolefin separators is the key to enhancing their performance.

[0004] Traditional modification methods, such as surface coating and chemical grafting, have problems such as complex processes, easy introduction of impurities, and uneven modification effects, and the performance of commonly used modification materials (such as acrylic acid) is limited. Therefore, it has become an urgent task to develop a new process and new modification materials with simple operation, precise modification, and uniform effects. In recent years, the combination of electron beam irradiation technology and polyvinyl alcohol (PVA) has provided an innovative solution for separator modification. This technology not only has simple operation but also can achieve precise and uniform modification effects, opening up a new way to improve the performance of lithium - ion battery separators. Summary of the Invention

[0005] To overcome the limitations of existing modification processes, the purpose of the present invention is to provide a method for treating a polyvinyl alcohol-modified highly wettable separator for lithium-ion batteries by electron beam irradiation. Through electron beam irradiation technology, polyvinyl alcohol is grafted onto the surface of a polypropylene separator. As a polar polymer rich in hydroxyl groups (-OH), the multi-hydroxyl structure on its molecular chain can significantly improve the interfacial compatibility between the separator and the electrolyte. Therefore, the synergistic effect of the surface functional groups after grafting and the active sites obtained by electron beam irradiation significantly improves the wetting performance of the separator, thereby effectively enhancing the ionic conductivity and optimizing the performance of lithium-ion batteries under high-power conditions. At the same time, polyvinyl alcohol can also construct a three-dimensional network structure through intermolecular hydrogen bonding. Its successful grafting can greatly improve the thermal stability of the polypropylene separator, reduce the probability of thermal runaway caused by excessive thermal shrinkage of the separator, and improve the safety level of the battery under high-temperature conditions.

[0006] To solve the problems of the existing technology, the technical solution adopted by the present invention is as follows:

[0007] A method for treating a polyvinyl alcohol-modified highly wettable separator for lithium-ion batteries by electron beam irradiation, comprising the following steps:

[0008] 1) Preparation of graft monomer solution:

[0009] Dissolve polyvinyl alcohol particles in deionized water accounting for two-thirds of the total volume, heat to 65 - 85 °C, stir evenly, then slowly add the remaining deionized water, continue stirring, cool to room temperature, and filter to obtain a polyvinyl alcohol solution with a mass fraction of 1 - 10%;

[0010] 2) Immerse the ultrasonically cleaned and dried separator in the polyvinyl alcohol solution for 1 - 3 h. Among them, the conditions for ultrasonic cleaning and drying are ultrasonic time of 10 - 60 min, ultrasonic frequency of 80 - 100 Hz, drying temperature of 40 - 60 °C, and drying time of 360 - 720 min;

[0011] 3) After electron beam irradiation treatment of the polyvinyl alcohol solution with the immersed separator, wash the separator, and then wash it 3 times with deionized water to remove unreacted polyvinyl alcohol monomers and homopolymers, and dry it at 40 - 60 °C for 12 - 24 h to obtain the product.

[0012] As an improvement, in step 1), the mass fraction of the polyvinyl alcohol solution is 2%; the polyvinyl alcohol is of the 1788 low-viscosity type with a degree of alcoholysis of 87.0 - 89.0 (mol / mol).

[0013] As an improvement, in step 2), the ultrasonic time is 40 min, the ultrasonic frequency is 100 Hz, the drying temperature is 60 °C, and the drying time is 720 min.

[0014] As an improvement, in step 2), the polypropylene separator is immersed in the graft monomer solution for 2.5 h.

[0015] As an improvement, in step 3), the energy of the electron beam irradiation is 50 - 200 keV; the irradiation dose is 1 - 200 kGy, the nitrogen value is 99%, and the irradiation time is 1 - 90 s.

[0016] As an improvement, in step 3), the energy of the electron beam irradiation is 100 - 200 keV, and the irradiation dose is 10 - 200 kGy.

[0017] As an improvement, in step 3), the drying temperature is 60 °C and the time is 720 min.

[0018] The application of the above polyvinyl alcohol modified highly wettable separator as a negative electrode material in a lithium - ion battery.

[0019] Beneficial effects:

[0020] Compared with the prior art, the method for electron beam irradiation treatment of a polyvinyl alcohol modified highly wettable separator for a lithium - ion battery of the present invention has the following advantages:

[0021] 1. The present invention successfully grafts polyvinyl alcohol on the surface of a commercial polypropylene separator to obtain a polypropylene separator with excellent high - wetting performance. The process has the advantages of simple operation, being suitable for large - scale production, and can achieve precise and efficient modification treatment with remarkable modification effects. No other reagents such as initiators need to be added during the preparation process, avoiding the generation of impurities, with high - efficiency directional modification and precise treatment.

[0022] 2. The present invention selects polyvinyl alcohol as the grafting agent, which can not only significantly improve the wetting performance of the separator, reducing the contact angle of the separator from 36.1° of the commercial polypropylene separator to 12.4°. This is attributed to the multi - hydroxyl structure on the PVA molecular chain, which can significantly improve the interfacial compatibility between the separator and the electrolyte. It can also benefit from the intermolecular hydrogen - bond interaction of polyvinyl alcohol to construct a three - dimensional network structure, thereby effectively enhancing the thermal stability of the separator, especially significantly reducing the degree of thermal shrinkage under high - temperature conditions. Compared with the severe shrinkage phenomenon (81% shrinkage rate) of the non - irradiated graft - modified separator, the thermal shrinkage rate of the irradiated graft - modified separator can be as low as 30%. Therefore, it has broad application potential and development prospects.

[0023] 3. The highly wettable polypropylene separator modified by the present invention can greatly improve the thermal stability while ensuring high wetting performance.

[0024] 4. The present invention realizes the synergistic optimization of surface chemical modification and the integrity of the porous structure by grafting polyvinyl alcohol and precisely controlling the irradiation dose. The combined action of the polar functional groups contained in the monomer and the active sites obtained by irradiation designs a separator with both high wettability and high thermal stability, providing a new technical approach for the development of high-performance lithium-ion battery separators. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 SEM spectrum of the polyvinyl alcohol-modified highly wettable separator prepared in Example 1;

[0026] Figure 2 FTIR spectrum of the polyvinyl alcohol-modified highly wettable separator prepared in Example 1;

[0027] Figure 3 Contact angle test diagram of the polyvinyl alcohol-modified highly wettable separator prepared in Example 1;

[0028] Figure 4 DSC spectrum of the polyvinyl alcohol-modified highly wettable separator prepared in Example 1;

[0029] Figure 5 EIS spectrum of the polyvinyl alcohol-modified highly wettable separator prepared in Example 1;

[0030] Figure 6 Rate performance diagram of the polyvinyl alcohol-modified highly wettable separator prepared in Example 1. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] To better understand the technical solutions of the present application, the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0032] It should be clear that the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts belong to the scope of the present application.

[0033] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "the" and "said" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0034] It should be understood that the term "and / or" used herein is merely a relational term describing associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. Additionally, the character " / " in this text generally indicates that the associated objects before and after are in an "or" relationship.

[0035] In the present invention, polyvinyl alcohol is grafted onto the surface of a polypropylene separator, which can not only construct an effective support structure but also significantly improve the mechanical properties of the separator. In addition, polyvinyl alcohol belongs to alcohol substances and contains abundant hydroxyl groups, showing excellent electrolyte affinity and effectively improving the performance of the separator under high-power conditions. Meanwhile, when the polypropylene separator is treated by an electron beam irradiation process, the polymer chains can be efficiently broken, and a large number of active sites are generated on the surface. These active sites can induce cross-linking and trigger more chemical reactions, thereby enhancing the mechanical strength and thermal stability of the separator. Therefore, the present invention provides a novel grafting material based on polyvinyl alcohol and a process method for modifying a polypropylene separator by an electron beam irradiation technique. The method will be described in detail below in combination with specific embodiments.

[0036] A method for treating a polyvinyl alcohol-modified highly wettable separator for a lithium-ion battery by electron beam irradiation, comprising the following steps:

[0037] 1) Preparation of graft monomer solution:

[0038] Dissolve polyvinyl alcohol particles in deionized water accounting for two-thirds of the total volume, heat to 65 - 85 °C, stir evenly, then slowly add the remaining deionized water, continue stirring, cool to room temperature, and filter to obtain a polyvinyl alcohol solution with a mass fraction of 1 - 10%;

[0039] 2) Immerse the ultrasonically cleaned and dried separator in the polyvinyl alcohol solution for 1 - 3 h, wherein the conditions for ultrasonic cleaning and drying are an ultrasonic time of 10 - 60 min, an ultrasonic frequency of 80 - 100 Hz, a drying temperature of 40 - 60 °C, and a drying time of 360 - 720 min;

[0040] 3) After the polyvinyl alcohol solution with the immersed separator is subjected to electron beam irradiation treatment, wash the separator, and then wash it 3 times with deionized water to remove unreacted polyvinyl alcohol monomers and homopolymers, and dry it at 40 - 60 °C for 12 - 24 h.

[0041] Specifically, in step 1), the mass fraction of the polyvinyl alcohol solution is 2%; the polyvinyl alcohol is of the 1788 low-viscosity type with an alcoholysis degree of 87.0 - 89.0 (mol / mol).

[0042] In step 2), the ultrasonic time is 40 min, the ultrasonic frequency is 100 Hz, the drying temperature is 60 °C, and the drying time is 720 min.

[0043] In step 2), the polypropylene separator is immersed in the graft monomer solution for 2.5 h.

[0044] In step 3), the energy of the electron beam irradiation is 50 - 200 keV; the irradiation dose is 1 - 200 kGy, the nitrogen value is 99%, and the irradiation time is 1 - 90 s.

[0045] In step 3), the energy of the electron beam irradiation is 100 - 200 keV, and the irradiation dose is 10 - 200 kGy.

[0046] In step 3), the drying temperature is 60 °C and the time is 720 min.

[0047] The application of the above polyvinyl alcohol modified highly wettable separator as a negative electrode material in a lithium-ion battery.

[0048] Specifically, the negative electrode is composed of a carrier and a coating layer. The carrier has a sheet structure, and the coating layer evenly covers the surface of the carrier. The components of the coating layer include a conductive agent, a binder, and the mentioned negative electrode active material for a lithium-ion battery. In practical applications, the ratio of these three components can be configured according to 1:1:8. The carrier can be a copper foil, a carbon-coated aluminum foil, or a carbon paper. The conductive agent is acetylene black, and the binder is PVDF (a solution with a mass fraction of 8%). However, it should be noted that those skilled in the art can flexibly adjust the ratio of each component according to specific requirements, and the embodiments of the present invention do not provide strict limitations on this.

[0049] For better understanding, the technical solutions provided in this application will be described in detail below in conjunction with specific embodiments.

[0050] Example 1

[0051] A method for treating a polyvinyl alcohol modified highly wettable separator for a lithium-ion battery by electron beam irradiation, comprising the following steps:

[0052] (1) At 25 °C, according to the mass ratio of polyvinyl alcohol to deionized water of 1:50, dissolve 2 g of PVA (polyvinyl alcohol) in 98 g of deionized water. First, add two-thirds of the deionized water and heat with stirring for dissolution. The heating temperature is 85 °C and the stirring time is 1 h. Then slowly add the remaining deionized water and continue heating and stirring for 1 h. Subsequently, cool to room temperature and perform filtration to obtain the final graft monomer solution. If the concentration of polyvinyl alcohol is too high, or the electron beam irradiation energy and dose are too high, it will cause excessive grafting of polyvinyl alcohol monomers on the surface of the polypropylene diaphragm, thus blocking the pores of the diaphragm, hindering the transport of ions, and affecting its performance under high power. If the concentration of polyvinyl alcohol is too low, or the electron beam irradiation energy and dose are too low, the effect is not obvious. It should be particularly noted that the polyvinyl alcohol solution needs to be heated with stirring, and the stirring should be sufficient to avoid local overheating and precipitation. Also, the remaining deionized water needs to be added slowly to avoid a large amount of foaming and agglomeration phenomena.

[0053] (2) Place the commercial polypropylene diaphragm (Celgard 3401) in absolute ethanol for ultrasonic cleaning for 40 min. After cleaning, place it in a vacuum drying oven for drying. The drying temperature is 60 °C and the time is 720 min. Immerse the ultrasonically cleaned and dried polypropylene diaphragm into the graft monomer solution prepared in step (1) for 2.5 h.

[0054] (3) Perform electron beam irradiation treatment on the polypropylene diaphragm in step (2) together with the polyvinyl alcohol solution. The conditions of the electron beam irradiation process are: irradiation energy 200 KeV, irradiation dose 100 kGy, nitrogen value 99%, and irradiation time 10 s. Then wash the diaphragm grafted with polyvinyl alcohol with deionized water 3 times to remove unreacted polyvinyl alcohol monomers and homopolymers. Finally, dry it in a vacuum drying oven at a drying temperature of 60 °C for 720 min to obtain the polyvinyl alcohol-modified highly wettable diaphragm.

[0055] Example 2

[0056] Except that the electron beam irradiation dose is 20 kGy, the rest is the same as in Example 1.

[0057] Example 3

[0058] Except that the electron beam irradiation dose is 50 kGy, the rest is the same as in Example 1.

[0059] Example 4

[0060] Except that the electron beam irradiation dose is 150 kGy, the rest is the same as in Example 1.

[0061] Example 5

[0062] Except that the dose of electron beam irradiation is 200 kGy, the rest is the same as in Example 1.

[0063] Example 6

[0064] Except that the preparation concentration of the polyvinyl alcohol solution is 5% (mass fraction), the rest is the same as in Example 1.

[0065] Comparative Example 1

[0066] Except that the electron beam irradiation is changed to an ultraviolet radiation process, the rest is the same as in Example 1, where the parameters of the ultraviolet radiation process are irradiation for 30 min under a 300 W ultraviolet lamp at 30 cm.

[0067] The materials prepared in Example 1 were characterized and performance tested, and the results are as follows:

[0068] Figure 1 is the SEM pattern of the polyvinyl alcohol modified highly wettable separator prepared in Example 1. It can be seen from the figure that there are granular substances on the surface of the separator, which proves that polyvinyl alcohol monomers have been successfully grafted onto the polypropylene separator by using electron beam irradiation technology, and the irradiation breaks the polymer chain, resulting in an increase in pores.

[0069] Figure 2 is the FTIR pattern of the polyvinyl alcohol modified highly wettable separator prepared in Example 1. Compared with the polypropylene separator before grafting modification without irradiation, it contains a large number of polar groups such as -OH, C=O, C-O, and C-O-C, which are typical characteristics of polyvinyl alcohol and free radicals generated by electron beam irradiation to break the polymer chain. This proves that polyvinyl alcohol has been successfully grafted onto the polypropylene separator by using electron beam irradiation technology, and a large number of active sites are generated during this process.

[0070] Figure 3 is the contact angle test diagram of the highly wettable lithium-ion battery separator prepared in Example 1, which is significantly smaller than that of the separator without grafting modification by irradiation. This proves that due to polyvinyl alcohol and electron beam irradiation, the increased polar groups in the grafted modified polypropylene separator improve the wettability of the separator, thus enhancing the affinity for the electrolyte.

[0071] Figure 4 is the DSC pattern of the polyvinyl alcohol modified highly wettable separator prepared in Example 1. The melting temperature of the electron beam irradiated grafted modified polypropylene separator obtained in Example 1 shows almost no change, indicating that the thermal stability of the separator after grafting polyvinyl alcohol remains good and is not affected.

[0072] Figure 5This is the EIS spectrum of the polyvinyl alcohol modified high wettability diaphragm prepared in Example 1. The resistance of the electron beam irradiated grafted modified polypropylene diaphragm obtained in Example 1 is smaller, so the ion conductivity of the modified polypropylene diaphragm after grafting polyvinyl alcohol is increased, indicating that the diaphragm after irradiation grafting polyvinyl alcohol has improved lyophilicity through the multi-hydroxy structure, making the ion movement rate faster, thereby improving the performance under high power.

[0073] Weigh 240 mg of lithium vanadate as the active material, add 30 mg of acetylene black as the conductive agent, and 600 mg of 5% PVDF solution as the binder, and mix the three materials thoroughly to prepare a uniform slurry. Subsequently, the slurry is evenly coated on the surface of a copper foil with a diameter of 1.2 cm, and the copper foil coated with the active material lithium vanadate is used as the negative electrode material of the lithium ion battery.

[0074] Rate performance test: Under room temperature conditions, the prepared batteries were tested on the LAND battery testing system, and the specific capacity of the batteries was tested at current densities of 0.2C, 0.5C, 1C, 2C, 5C, 10C, 20C, 30C, 40C, and 50C respectively.

[0075] Figure 6 The figure is a rate performance diagram of the lithium vanadate half-charge matched with the polyvinyl alcohol modified high wettability diaphragm prepared in Example 1. It can be seen from the figure that the lithium vanadate half-charge matched by the diaphragm after radiation grafting modification is 388mAh / g at 0.2C; at a high current density of 50C, it still has a high specific capacity of 142mAh / g, proving that after the polyvinyl alcohol is irradiated and grafted to the polypropylene diaphragm through electron beam irradiation technology, it has excellent electrochemical properties. The contact angle and thermal shrinkage rate of the diaphragm prepared in the above example were tested, and the diaphragm was assembled into a button battery with the prepared lithium vanadate and metal lithium sheet to test its rate performance. The experimental results are shown in the data shown in Table 1.

[0076] Table 1. Thermal shrinkage, contact angle and rate performance data of the diaphragm obtained in different embodiments

[0077]

[0078] As can be seen from Table 1, the concentration of the grafted monomer solution should match the dose of electron beam irradiation. If the concentration of the grafted monomer solution is too low and the irradiation dose is low, polyvinyl alcohol may not be successfully grafted onto the polypropylene diaphragm, thus failing to achieve the modification effect; while if the concentration of the grafted monomer solution is too high and the irradiation dose is high, it may cause excessive grafting of polyvinyl alcohol onto the polypropylene diaphragm, resulting in the pores on the diaphragm being blocked, affecting the transmission of ions and causing its high-power performance to deteriorate. Reasonable monomer concentration and irradiation dose can further optimize the thermal shrinkage and wettability of the diaphragm to achieve the best effect.

[0079] In Example 1, the polypropylene separator modified by grafting polyvinyl alcohol through electron beam irradiation shows significantly improved thermal stability, electrolyte affinity, and rate performance under high-power conditions as a lithium-ion battery separator. Further proof shows that the grafting of polyvinyl alcohol not only improves the electrolyte affinity of the separator but also effectively reduces the thermal shrinkage rate. At the same time, the electron beam irradiation technology also plays a positive role in enhancing the thermal stability and wettability of the separator, and compared with the ultraviolet radiation process, its modification effect is more obvious, and the performance of the obtained separator is more excellent.

[0080] The above has schematically described the present invention and its implementation manners. This description is not restrictive, and what is shown in the drawings is only one of the implementation manners of the present invention, and the actual structure is not limited thereto. Therefore, if those of ordinary skill in the art are inspired by it and design similar structural manners and embodiments to this technical solution without creative work without departing from the purpose of the present invention, they shall fall within the protection scope of the present invention.

Claims

1. A method for treating a polyvinyl alcohol-modified high wettability separator for a lithium-ion battery by electron beam irradiation, characterized in that: The following steps are involved: 1) Preparation of grafting monomer solution: Dissolve the polyvinyl alcohol particles in deionized water accounting for two-thirds of the total volume, heat to 65-85°C, stir evenly, then slowly add the remaining deionized water, continue stirring, cool to room temperature, and filter to obtain a polyvinyl alcohol solution with a mass fraction of 1-10%; 2) Soaking the ultrasonically cleaned and dried diaphragm in a polyvinyl alcohol solution for 1-3 hours, wherein the ultrasonic cleaning and drying conditions are as follows: ultrasonic time of 10-60 minutes, ultrasonic frequency of 80-100 Hz, drying temperature of 40-60°C, and drying time of 360-720 minutes; 3) After the polyethanol solution in which the diaphragm is soaked is subjected to electron beam irradiation treatment, the diaphragm is cleaned and then washed three times with deionized water to remove unreacted polyvinyl alcohol monomer and homopolymer, and then dried at 40-60°C for 12-24h.

2. The method for treating a polyvinyl alcohol-modified high wettability separator for a lithium-ion battery by electron beam irradiation according to claim 1, characterized in that: The mass fraction of the polyvinyl alcohol solution in step 1) is 2%; the polyvinyl alcohol is 1788 low-viscosity type, and the alcoholysis degree is 87.0-89.0 (mol / mol).

3. The method for treating a polyvinyl alcohol-modified high wettability separator for a lithium-ion battery by electron beam irradiation according to claim 1, characterized in that: In step 2), the ultrasonic time is 40 min, the ultrasonic frequency is 100 Hz, the drying temperature is 60° C., and the drying time is 720 min.

4. The method for treating a polyvinyl alcohol-modified high wettability separator for a lithium-ion battery by electron beam irradiation according to claim 1, characterized in that: In step 2), the polypropylene membrane is immersed in the grafted monomer solution for 2.5 hours.

5. The method for treating a polyvinyl alcohol-modified high wettability separator for lithium-ion batteries by electron beam irradiation according to claim 1, characterized in that: In step 3), the energy of the electron beam irradiation is 50 to 200 KeV; the irradiation dose is 1 to 200 kGy, the nitrogen value is 99%, and the irradiation time is 1 to 90 s.

6. The method for treating a polyvinyl alcohol-modified high wettability separator for lithium-ion batteries by electron beam irradiation according to claim 1, characterized in that: In step 3), the energy of the electron beam irradiation is 100-200 KeV, and the irradiation dose is 10-200 kGy.

7. The method for treating a polyvinyl alcohol-modified high wettability separator for lithium-ion batteries by electron beam irradiation according to claim 1, characterized in that: The drying temperature in step 3) is 60°C and the drying time is 720 minutes.

8. Use of the polyvinyl alcohol-modified high wettability separator prepared by the method according to any one of claims 1 to 7 as a negative electrode material in a lithium ion battery.

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