Fluorinated modified porous polymer as well as preparation method and application thereof

Abstract

The invention discloses a fluorinated modified porous polymer as well as a preparation method and application thereof, and relates to the technical field of polymer modification. According to the preparation method, a polycyclic aromatic hydrocarbon compound and a Lewis acid catalyst are taken as raw materials and subjected to heat treatment to prepare the porous polymer, a high-temperature treatment step is added after heat treatment, and the electronic conductivity is further improved while good intrinsic porosity of the porous polymer with large conjugation or full conjugation formed by solid-phase reaction is reserved; polar groups can be effectively introduced into the conjugated porous polymer through plasma ball-milling fluorination modification, the interface stability of a negative electrode electrolyte is improved, and the electrochemical performance of the material is improved while good intrinsic porosity and electronic conductivity are reserved.

Description

Technical Field

[0001] This invention relates to the field of polymer modification technology, and more specifically, to a fluorinated modified porous polymer, its preparation method, and its application. Background Technology

[0002] With the widespread application of lithium-ion batteries in electric vehicles, portable electronic devices, and other fields, the performance optimization of anode materials has become a research hotspot. Porous polymer-derived carbon-based materials are considered ideal anode material candidates due to their high specific surface area, abundant pore structure, and good conductivity. However, their electrochemical performance still needs further improvement to meet the requirements of high energy density and long cycle life.

[0003] Currently, modification methods for porous polymer-derived carbon-based materials can improve energy density and cycle performance to some extent, but the improvement is not ideal. Summary of the Invention

[0004] The purpose of this invention is to provide a fluorinated modified porous polymer, its preparation method and application, which aims to significantly improve the electrochemical performance of porous polymers as negative electrode active materials.

[0005] This invention is implemented as follows: In a first aspect, the present invention provides a method for preparing a fluorinated modified porous polymer, comprising: Preparation of porous polymer substrates: Polycyclic aromatic hydrocarbon compounds and Lewis acid catalysts are mixed and heat-treated at 400℃-450℃, followed by high-temperature treatment at 800℃-1000℃. Plasma ball milling fluorination modification: The porous polymer substrate is subjected to plasma ball milling in a fluorine-containing gas atmosphere.

[0006] In an optional embodiment, the plasma ball milling treatment of the porous polymer substrate in a fluorine-containing gas atmosphere includes: placing the porous polymer substrate and grinding balls in a ball milling jar, sealing the ball milling jar, filling the ball milling jar with fluorine-containing gas, and installing and fixing the ball milling jar on a dielectric barrier discharge plasma-assisted high-energy ball milling machine for ball milling.

[0007] In an optional implementation, during the plasma ball milling process, the ball mill motor speed is set to 500 r / min-960 r / min, and the discharge current is 1.5A-2.5A. And / or, an intermittent ball milling process is adopted, controlling the running time of a single ball milling session to be 10 min-30 min, the interval between two adjacent ball milling sessions to be 10 min-30 min, and the total processing time to be 8 h-12 h.

[0008] In an optional embodiment, the fluorine-containing gas is selected from at least one of nitrogen trifluoride, carbon tetrafluoride, trifluoromethane, and sulfur hexafluoride; And / or, control the pressure of the fluorine-containing gas inside the ball mill jar to be 0.01 MPa-0.10 MPa; And / or, the dielectric material used for dielectric barrier discharge is selected from at least one of quartz, polypropylene, polytetrafluoroethylene and silicone rubber; And / or, the grinding ball is made of at least one of stainless steel, tungsten carbide and silicon carbide.

[0009] In an optional implementation, the heat treatment process is controlled to maintain the heat for 20-30 hours. And / or, during the high-temperature treatment, the heat preservation time is controlled to be 15h-20h.

[0010] In an optional embodiment, the polycyclic aromatic hydrocarbon compound used in the preparation of the porous polymer substrate is selected from at least one of anthraquinone, pentaquinone, and tetraazapentaquinone; And / or, the Lewis acid catalyst is selected from at least one of aluminum chloride, ferric chloride, cobalt chloride, and cerium chloride; And / or, the molar ratio of polycyclic aromatic hydrocarbons to Lewis acid catalysts is 1:(4-6); And / or, the polycyclic aromatic hydrocarbon compound and the Lewis acid catalyst are mixed and ground to obtain a mixed powder; the mixed powder is then subjected to heat treatment and high-temperature treatment.

[0011] In an optional embodiment, after high-temperature treatment, the crude product is mixed with an inorganic acid solution for reaction, and the resulting solid material is washed and dried; the crude product is then added to the inorganic acid solution and refluxed with stirring.

[0012] In an optional embodiment, the inorganic acid solution is a hydrochloric acid solution; And / or, the washing process includes: first washing with water until neutral, then washing with a solvent; the solvent may include ethanol or acetone.

[0013] Secondly, the present invention provides a fluorinated modified porous polymer, which is prepared by any of the methods for preparing fluorinated modified porous polymers described in the foregoing embodiments.

[0014] Thirdly, the present invention provides a lithium electrode comprising the fluorinated modified porous polymer of the aforementioned embodiments, prepared by using the fluorinated modified porous polymer as the negative electrode active material.

[0015] Fourthly, the present invention provides a lithium-ion battery including the lithium-ion electrode of the aforementioned embodiments.

[0016] This invention has the following beneficial effects: It prepares porous polymers from polycyclic aromatic hydrocarbons and Lewis acid catalysts through heat treatment. Adding a high-temperature treatment step after heat treatment further improves the electronic conductivity of the porous polymers with large or full conjugation formed by the solid-phase reaction while retaining good intrinsic porosity. Plasma ball milling and fluorination modification can effectively introduce polar groups into the conjugated porous polymers, improving the stability of the negative electrode electrolyte interface and enhancing the electrochemical performance of the material while maintaining good intrinsic porosity and electronic conductivity.

[0017] In addition, plasma ball milling can significantly shorten reaction time, precisely control the degree of fluorination and reaction conditions, and reduce environmental pollution. Compared with traditional high-temperature fluorination processes, plasma fluorination consumes less energy and is more economical. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a 20,000x magnified SEM image of pAQ900 in Embodiment 2 of the present invention; Figure 2 This is a 20,000x magnified SEM image of pAQ900F in Embodiment 2 of the present invention; Figure 3 The XRD patterns of AQ, pAQ900, and pAQ900F in Embodiment 2 of the present invention are shown below. Figure 4 The infrared spectra of AQ, pAQ900, and pAQ900F in Embodiment 2 of the present invention; Figure 5 This is the XPS C 1s fine spectrum of pAQ900 in Embodiment 2 of the present invention; Figure 6 The XPS C1s fine spectrum of pAQ900F in Example 2 of this invention; Figure 7 The XPS F1s fine spectrum of pAQ900F in Embodiment 2 of the present invention; Figure 8 The isothermal nitrogen adsorption curves (a) and semi-pore size distribution curves (b) of pAQ900 and pAQ900F in Example 2 of the present invention are shown. Figure 9 The symmetric cell based on pAQ900F-Li and lithium foil in Example 4 of this invention operates at 1.0 mA h / cm.2 Fixed area capacity and 1.0 mA / cm² 2 Cyclic performance at current density. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0021] Fluorination, as an effective surface modification method, can significantly improve the electrochemical performance of materials. Fluorination optimizes electrochemical performance by introducing fluorine into the material surface, altering its chemical properties and microstructure. Common fluorination methods include gas-phase fluorination and chemical fluorination. Gas-phase fluorination achieves fluorination by exposing the material to a fluorine-containing gas (such as HF or F2) at high temperatures, while chemical fluorination utilizes the reaction of fluorine-containing compounds (such as NH4F) in solution.

[0022] This invention creatively employs plasma ball milling technology to modify porous polymers, significantly improving the efficiency of the fluorination reaction through the synergistic effect of mechanical energy and plasma energy. High-energy particles in the plasma (such as electrons, ions, and free radicals) can activate the material surface, promoting the fluorination reaction. Traditional fluorination methods typically require high temperatures or solutions, while plasma ball milling technology can achieve highly efficient fluorination at lower temperatures. This not only reduces energy consumption and avoids damage to the material structure from high temperatures but also prevents the generation of toxic HF gas. Plasma ball milling technology can also achieve uniform fluorination of the material surface, and the fluorination effect can be optimized through precise control of plasma parameters.

[0023] This invention provides a method for preparing a fluorinated modified porous polymer, comprising: S1. Preparation of porous polymer substrates Polycyclic aromatic hydrocarbons (PAHs) and Lewis acid catalysts are mixed and first heat-treated at 400℃-450℃, followed by high-temperature treatment at 800℃-1000℃. This high-temperature treatment after the initial heat treatment promotes further intramolecular or intermolecular cross-linking of the conjugated porous organic polymer, forming new covalent bonds. This process promotes electron transfer between conjugated structures, further improving polymer conductivity; it also enhances the overall aromaticity of the molecular chain, further optimizing molecular structural stability and ensuring that the intrinsic structure of the raw materials used in the plasma ball milling fluorination process is not damaged.

[0024] It should be noted that this step is a solid-phase ionic thermal oxidative coupling reaction (Scholl coupling reaction) using a strong Lewis acid as a catalyst. This reaction can directly construct carbon-carbon bonds on adjacent aromatic rings to connect adjacent reactants, avoiding the use of large amounts of solvent and simplifying the preparation steps. It can effectively construct porous polymers with large conjugated frameworks, ensuring that the material itself has high intrinsic porosity and electronic conductivity. Further high-temperature treatment can promote further cross-linking within or between molecules, forming new covalent bonds, thereby optimizing the material properties. For conjugated polymers containing aromatic rings, high temperature may promote condensation reactions between aromatic rings, forming more stable fused ring structures, thereby promoting electron transfer between conjugated structures and improving polymer conductivity. Through the plasma ball milling fluorination process in step S2, the surface of powder particles can be fluorinated without destroying the large conjugated framework with high electronic conductivity.

[0025] Specifically, during heat treatment, the operating temperature is controlled at 400℃-450℃, such as 400℃, 410℃, 420℃, 430℃, 440℃, 450℃, etc. Conventional heat treatment equipment is sufficient, with no special requirements. During high-temperature treatment, the operating temperature is controlled at 800℃-1000℃, such as 800℃, 850℃, 900℃, 950℃, 1000℃, etc. High-temperature treatment aims to eliminate surface carbon-hydrogen bonds, improve the conjugation degree of the framework, optimize the material's conductivity, and lay a good foundation for subsequent fluorination. If the high-temperature treatment temperature is too high or too low, it will be detrimental to improving the polymer's electronic conductivity.

[0026] In some embodiments, during the heat treatment process, the holding time is controlled to be 20h-30h, such as 20h, 23h, 25h, 28h, 30h, etc.; during the high-temperature treatment process, the holding time is controlled to be 15h-20h, such as 15h, 18h, 20h, etc.

[0027] In some embodiments, the polycyclic aromatic hydrocarbon (PAH) used in the preparation of the porous polymer substrate is selected from at least one of anthraquinone, pentabenzoquinone, and tetraazapentabenzoquinone. The PAH can be any one or more of these compounds, which are derivatives of linear polyacene and possess a highly conjugated structure, thus improving the electrochemical performance of the product. The Lewis acid catalyst is selected from at least one of aluminum chloride, ferric chloride, cobalt chloride, and cerium chloride. The Lewis acid catalyst can be any one or more of these compounds. The molar ratio of the PAH to the Lewis acid catalyst is 1:(4-6), such as 1:4, 1:5, 1:6, etc.

[0028] To improve the uniformity of the mixture of polycyclic aromatic hydrocarbons (PAHs) and Lewis acid catalysts, the PAHs and Lewis acid catalysts are mixed and ground to obtain a mixed powder, which is then subjected to heat treatment and high-temperature treatment. The grinding method is not limited; common mechanical grinding methods, such as using a mortar and pestle, can be employed.

[0029] In some embodiments, after high-temperature treatment, the obtained crude product is mixed with an inorganic acid solution for reaction. The resulting solid material is then washed and dried. Unreacted raw materials remaining on the surface are removed using the inorganic acid solution, and the final product is obtained after washing and drying. The inorganic acid solution is hydrochloric acid, but not limited to this. The crude product is added to the inorganic acid solution and refluxed with stirring for 10-15 hours. The washing method is not limited; for example, it can be washed with water until neutral, followed by solvent washing, but the washing method is not limited to this. The solvent used can be ethanol or acetone. The drying temperature is not limited; for example, it can be 80℃-100℃, with a vacuum degree of less than 0.1 MPa, and a drying time of more than 12 hours.

[0030] S2, Plasma ball milling fluorination modification Plasma ball milling of porous polymer substrates in a fluorine-containing atmosphere can effectively introduce polar groups into conjugated porous polymers, while maintaining good intrinsic porosity and electronic conductivity and improving the electrochemical performance of the material.

[0031] In some embodiments, the plasma ball milling process includes: placing a porous polymer substrate and grinding balls in a grinding jar, sealing the grinding jar, repeatedly filling the grinding jar with fluorine-containing gas to remove air from the jar, ensuring the purity and pressure of the fluorine-containing gas inside the jar, and then installing and fixing the grinding jar on a dielectric barrier discharge plasma-assisted high-energy ball mill for ball milling. The specific model of the dielectric barrier discharge plasma-assisted high-energy ball mill is not limited; for example, the Plasma-BM-S type plasma-assisted high-energy ball mill provided by Guangdong Huaxin Materials Innovation can be used.

[0032] In some embodiments, the fluorine-containing gas is selected from at least one of nitrogen trifluoride, carbon tetrafluoride, trifluoromethane, and sulfur hexafluoride, and the fluorine-containing gas can be any one or more of the above. The fluorine-containing gas used in this invention has a higher safety factor and lower cost. The pressure of the fluorine-containing gas in the ball mill jar is controlled at 0.01 MPa-0.10 MPa, such as 0.01 MPa, 0.03 MPa, 0.05 MPa, 0.08 MPa, 0.10 MPa, etc.

[0033] In some embodiments, during the plasma ball milling process, the ball mill motor speed is set to 500 r / min-960 r / min, such as 500 r / min, 600 r / min, 700 r / min, 800 r / min, 900 r / min, 960 r / min, etc.; the discharge current is 1.5A-2.5A, such as 1.5A, 1.8A, 2.0A, 2.3A, 2.5A, etc. Adjusting the discharge current and motor speed to improve the fluorination effect is beneficial for further improving the electrochemical performance of the product.

[0034] In some embodiments, an intermittent ball milling process is employed, where ball milling is performed for a period of time, followed by a pause before proceeding to the next stage of ball milling. The running time of a single ball milling session is controlled to be 10-30 minutes, such as 10 minutes, 20 minutes, or 30 minutes; the interval between two adjacent ball milling sessions is also 10-30 minutes, such as 10 minutes, 20 minutes, or 30 minutes. The total processing time is 8 hours to 12 hours, such as 8 hours, 9 hours, 10 hours, 11 hours, or 12 hours.

[0035] Furthermore, the dielectric material used in the dielectric barrier discharge is selected from at least one of quartz, polypropylene, polytetrafluoroethylene, and silicone rubber, and the dielectric material can be any one or more of the above. The grinding ball material is selected from at least one of stainless steel, tungsten carbide, and silicon carbide, and the grinding ball material can be any one or more of the above.

[0036] This invention also provides a fluorinated modified porous polymer, which is prepared by the preparation method provided in this invention. The fluorinated modified porous polymer prepared by the method provided in this invention has a highly conjugated or fully conjugated structure. Plasma ball milling fluorination modification can effectively introduce polar groups into the conjugated porous polymer, improve the stability of the negative electrode electrolyte interface, and improve the electrochemical performance of the material while retaining good intrinsic porosity and electronic conductivity.

[0037] This invention provides a lithium-ion electrode comprising a fluorinated modified porous polymer, prepared using the fluorinated modified porous polymer as the negative electrode active material. Due to the improvement of the negative electrode active material, the electrochemical performance of the lithium-ion electrode is further improved.

[0038] In some embodiments, the preparation process of the lithiated electrode includes: preparing a negative electrode sheet using a fluorinated modified porous polymer as the negative electrode active material using conventional methods; assembling the negative electrode sheet and a lithium sheet into a half-cell using conventional methods; then depositing metallic lithium through an electric current to prepare a lithiated polymer sample electrode; and removing the electrode from the battery and cleaning and drying it. Specific implementation steps for the lithiated electrode can be found later in the specification, but are not limited to the specific methods described below.

[0039] This invention also provides a lithium-ion battery, including the lithium-ion electrode provided in this invention, as well as a positive electrode, an electrolyte, a separator, etc. Improvements to the negative electrode are beneficial to enhancing the electrochemical performance of the lithium-ion battery.

[0040] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0041] Example 1 This embodiment provides a method for preparing a fluorinated modified porous polymer, specifically a fluorinated conjugated porous organic polymer pAQ800F. The steps are as follows: (1) Preparation of porous polymer substrates Heat treatment: Anthraquinone AQ (2.08 g, 10 mmol) and aluminum trichloride (8.0 g, 60 mmol) were ground in a mortar and mixed evenly to obtain a mixed powder. The mixed powder was transferred to a corundum ceramic boat, and the corundum crucible containing the mixed powder was placed in a tube furnace. An oil pump was connected to the gas outlet of the tube furnace, and the vacuum was evacuated to a pressure below 0.1 MPa. Then, argon gas was introduced until the gas pressure inside the tube furnace reached atmospheric pressure. The above evacuation and gas replacement operation was repeated three times to completely remove the air from the tube furnace. The tube furnace was programmed to heat at a rate of 5 K / min to 400 °C and held for 25 h to obtain the crude product. Then, the temperature was cooled to room temperature to obtain the product pAQ.

[0042] High-temperature treatment: The product pAQ was transferred to a corundum ceramic boat, and the corundum crucible containing pAQ was placed in a tube furnace. Argon gas was then introduced for 30 minutes to completely remove the air from the tube furnace. The tube furnace was programmed to heat at a rate of 5 K / min to 800℃ and held for 15 hours to obtain the crude product. The product was then cooled to room temperature.

[0043] Post-processing: After the tube furnace cools to room temperature, the corundum ceramic boat is removed, and the crude product powder is poured into a dilute hydrochloric acid solution with a concentration of 0.5-1 mol / L. The solution is heated to reflux and stirred under reflux for 12 hours. Then, it is filtered to obtain a solid powder. The solid powder is repeatedly washed with deionized water and ethanol. Then, it is placed in a vacuum drying oven at 80℃ and dried at a vacuum degree below 0.1 MPa for more than 12 hours to obtain the product pAQ800.

[0044] (2) Plasma ball milling fluorination modification The fluorinated conjugated porous organic polymer pAQ800F was prepared by plasma-assisted ball milling followed by CF4 plasma treatment. In this embodiment, the atmosphere inside the tank was maintained at CF4 purity (99.99%). The specific steps are as follows: Pack pAQ800 powder and grinding balls into the grinding jar. Apply vacuum sealing grease to the rubber rings on the end caps and the rubber rings on the shoulders of the electrode rods of the grinding jar, and then seal the grinding jar. Evacuate the grinding jar through the vacuum valve, and then fill it with CF4 gas at a gauge pressure of 0.02 MPa. Repeat this process three times to finally make the environmental conditions in the grinding jar approximately 0.02 MPa of CF4.

[0045] The grinding jar was installed and secured onto the ball mill (model Plasma-BM-S). The power was connected and the ball mill started. The operating mode was set to "intermittent operation, timed shutdown," with a running time of 30 minutes, an interval operation time of 30 minutes, and 8 restarts. The ball mill motor speed was set to 960 r / min, the discharge current to 2.0 A, and the grinding time to 8 hours, yielding the product pAQ800F.

[0046] Example 2 The only difference from Example 1 is that in the high-temperature treatment of step (1), 800℃ is changed to 900℃, and other parameters are the same as in Example 1. In this example, pAQ900 is obtained after step (1), and product pAQ900F is obtained after step (2).

[0047] Example 3 The only difference from Example 1 is that in the high-temperature treatment of step (1), 800℃ is changed to 1000℃, and other parameters are the same as in Example 1. In this example, pAQ1000 is obtained after step (1), and product pAQ1000F is obtained after step (2).

[0048] (1) Electron conductivity test The electronic conductivity of the product obtained in step (1) of Examples 1-3 was tested using the four-probe test method and compared with that of pAQ prepared in Example 1. The results are shown in Table 1.

[0049] Table 1. Results of electronic conductivity test

[0050] It can be seen that, compared with pAQ, high-temperature treatment can significantly improve the electronic conductivity of the sample, which is helpful for further electrochemical applications.

[0051] (2) Product characterization Scanning electron microscopy (SEM) tests were performed on pAQ900 and pAQ900F obtained in Example 2, and the results are as follows: Figure 1 and Figure 2 As shown. Figure 1 This is a 20,000x magnified SEM image of pAQ900 in Example 2; Figure 2This is a 20,000x magnified SEM image of pAQ900F in Example 2. The SEM image shows that the plasma-milled fluorinated particles maintain an irregular shape of 5-10 micrometers, and no obvious discontinuities appear on the surface, indicating that plasma milling did not cause significant morphological damage to the particles.

[0052] X-ray diffraction (XRD) tests were performed on AQ, pAQ900, and pAQ900F in Example 2, and the results are as follows: Figure 3 As shown. From Figure 3 It can be seen that the reactant small molecule AQ exhibits obvious diffraction peaks, showing a long-range ordered structure; the XRD pattern of the product pAQ900 obtained after heat treatment does not show obvious sharp peaks, indicating that the heat treatment successfully polymerized to form an amorphous structure, which is consistent with the characteristics of porous polymers; the XRD pattern of the fluorinated pAQ900F is not significantly different from that of pAQ900, indicating that fluorination did not destroy the original amorphous structure.

[0053] Infrared spectroscopy tests were performed on AQ, pAQ900, and pAQ900F in Example 2, and the results are as follows: Figure 4 As shown. From Figure 4 As can be seen from the infrared spectroscopy test results, both pAQ900 and pAQ900F in Example 2 showed obvious carbon-carbon double bond and carbon-oxygen double bond (carbonyl) signals, indicating that the chemical composition and microscopic molecular structure of the precursor molecules used were preserved through high-temperature treatment and plasma ball milling fluorination.

[0054] X-ray photoelectron spectroscopy (XPS) was performed on pAQ900 and pAQ900F in Example 2, and the results are as follows: Figure 5 , Figure 6 and Figure 7 As shown: from Figure 5 As can be seen, the presence of CO and C=O bonds in the XPS C 1s spectrum of pAQ900 in Example 2 indicates the preservation of the original aromatic structure and the generation of a large conjugated skeleton.

[0055] from Figure 6 and Figure 7 As can be seen, the XPS F 1s spectrum of pAQ900F in Example 2 shows a clear signal, which, through peak splitting, is confirmed to correspond to the CF bond signal, indicating that the sample was successfully fluorinated. The analysis of the C 1s spectrum also confirms the presence of CF bonds in the fluorinated product of Example 2, leading to the same conclusion. The XPS results fully demonstrate the feasibility of plasma ball milling for fluorinating porous polymers.

[0056] The fluoride content of pAQ800 / pAQ800F, pAQ900 / pAQ900F, and pAQ1000 / pAQ1000F was semi-quantitatively tested using XPS, and the results are summarized in Table 2.

[0057] Table 2. Fluoride content test results

[0058] Nitrogen isothermal adsorption / desorption tests were conducted on pAQ900 and pAQ900F in Example 2 using a specific surface area and pore volume / pore size analyzer. The total surface area, pore size, and distribution were obtained by fitting the adsorption / desorption curves using the analyzer's software. The results are as follows: Figure 8 As shown.

[0059] from Figure 8 It can be seen that the specific surface area of ​​pAQ900 and pAQ900F is 1285.684 m². 2 / g and 1205.483m 2 The / g indicates high porosity within the material; furthermore, the pore size and radius of both are mainly distributed within 10 Å, meaning they are mostly micropores. A comparison of the figures shows that the specific surface area decreases slightly after fluorination, but the change is not significant; the adsorption-desorption properties are retained, and the pore structure remains largely unchanged.

[0060] The internal pore test proved that the present invention successfully synthesized a plasma-milled fluorinated porous polymer with high internal porosity.

[0061] (3) Battery performance test A battery was fabricated using pAQ900F obtained in Example 2 as the negative electrode active material. The performance of the battery was tested, and the results are as follows: Figure 9 As shown.

[0062] The negative electrode active material, conductive carbon black, and binder are mixed and dispersed in N-methylpyrrolidone (NMP) at a mass ratio of 8:1:1. The mixture is stirred at high speed to remove internal air bubbles, and then coated onto copper foil using a scraper. Subsequently, it is transferred to a forced-air drying oven and heated at 80 °C to remove the NMP solvent, and then transferred to a vacuum drying oven and vacuum dried overnight at 105 °C. The dried electrode sheet is removed from the vacuum drying oven and cut into original sheets with a diameter of 14 mm for use as electrode sheets in battery assembly.

[0063] The assembly method for the half-cell is as follows: The half-cell is assembled using a 2025 model button cell battery case, and the following order is used: negative electrode case, electrode plate, separator, electrolyte, lithium plate, gasket, spring plate, positive electrode case, and then pressure is applied to fasten the battery case tightly; the electrolyte is a commercially available lithium battery electrolyte with a composition of 1,3-dioxolane (DOL): ethylene glycol dimethyl ether (DME) = 1:1 (volume ratio) and 2 wt% lithium nitrate (LiNO3) in a 1 mol / L lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) solution; the separator is a commercially available polypropylene separator; after assembly, the battery is allowed to stand for 10 hours before electrochemical testing is performed.

[0064] The assembly method of the symmetrical cell is as follows: Using the above half-cell, through 1 mA / cm 2 Deposition at a current density of 20 mA h / cm 2 Lithium-based polymer sample electrodes were prepared using metallic lithium. The lithium-based electrodes were then removed from the battery, cleaned with 1,3-dioxolane (DOL) and dimethyl carbonate (DMC), and dried under low pressure. Symmetrical cells were assembled using the dried lithium-based electrodes or lithium sheets with the same electrolyte. The symmetric cells were assembled using a 2032 coin cell case, placed in the following order: negative electrode case, gasket, electrode, separator, electrolyte, electrode, gasket, spring sheet, positive electrode case, and then pressurized to secure the battery case. A commercially available polypropylene separator was used. After assembly, the cells were allowed to stand for 10 hours for Li stripping / plating rate capability and long-term performance testing.

[0065] The batteries were installed on the Xinwei Electrochemical Cyclic Tester (manufacturer: Shenzhen Xinwei Battery Testing Equipment Co., Ltd., product model: BTS-4000 Power Battery Testing System) to conduct different battery performance tests.

[0066] from Figure 9 It can be seen that the composite lithium anode prepared based on the fluorinated porous polymer material synthesized in this work exhibits a significantly improved cycle life compared to lithium metal. The performance improvement should be attributed to the combined effect of the porous structure, high conductivity, fluorination and other physicochemical properties of the material.

[0067] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a fluorinated modified porous polymer, characterized in that, include: Preparation of porous polymer substrates: Polycyclic aromatic hydrocarbon compounds and Lewis acid catalysts are mixed and heat-treated at 400℃-450℃, followed by high-temperature treatment at 800℃-1000℃. Plasma ball milling fluorination modification: The porous polymer substrate is subjected to plasma ball milling treatment in a fluorine-containing gas atmosphere.

2. The preparation method according to claim 1, characterized in that, The process of performing plasma ball milling on the porous polymer substrate in a fluorine-containing gas atmosphere includes: placing the porous polymer substrate and grinding balls in a ball milling jar, sealing the ball milling jar, filling the ball milling jar with the fluorine-containing gas, and installing and fixing the ball milling jar on a dielectric barrier discharge plasma-assisted high-energy ball milling machine for ball milling.

3. The preparation method according to claim 2, characterized in that, During the plasma ball milling process, the ball mill motor speed is set to 500 r / min-960 r / min, and the discharge current is 1.5A-2.5A. And / or, an intermittent ball milling process is adopted, controlling the running time of a single ball milling session to be 10 min-30 min, the interval between two adjacent ball milling sessions to be 10 min-30 min, and the total processing time to be 8 h-12 h.

4. The preparation method according to claim 2, characterized in that, The fluorine-containing gas is selected from at least one of nitrogen trifluoride, carbon tetrafluoride, trifluoromethane, and sulfur hexafluoride; And / or, control the pressure of the fluorine-containing gas inside the ball mill jar to be 0.01 MPa-0.10 MPa; And / or, the dielectric material used for dielectric barrier discharge is selected from at least one of quartz, polypropylene, polytetrafluoroethylene and silicone rubber; And / or, the grinding ball is made of at least one of stainless steel, tungsten carbide and silicon carbide.

5. The preparation method according to claim 1, characterized in that, During the heat treatment process, the holding time is controlled to be 20h-30h; And / or, during the high-temperature treatment, the heat preservation time is controlled to be 15h-20h.

6. The preparation method according to claim 1, characterized in that, In the preparation of the porous polymer substrate, the polycyclic aromatic hydrocarbon compound used is selected from at least one of anthraquinone, pentabenzoquinone, and tetraazapentabenzoquinone; And / or, the Lewis acid catalyst is selected from at least one of aluminum chloride, ferric chloride, cobalt chloride, and cerium chloride; And / or, the molar ratio of the polycyclic aromatic hydrocarbon compound to the Lewis acid catalyst is 1:(4-6); And / or, the polycyclic aromatic hydrocarbon compound and the Lewis acid catalyst are mixed and ground to obtain a mixed powder; the mixed powder is then subjected to heat treatment and high-temperature treatment.

7. The preparation method according to claim 1, characterized in that, After high-temperature treatment, the crude product is mixed with an inorganic acid solution for reaction. The resulting solid material is washed and dried. The crude product is then added to the inorganic acid solution and refluxed with stirring.

8. The preparation method according to claim 7, characterized in that, The inorganic acid solution is a hydrochloric acid solution; And / or, the washing process includes: first washing with water until neutral, and then washing with a solvent, including ethanol or acetone.

9. A fluorinated modified porous polymer, characterized in that, It is prepared by the method for preparing the fluorinated modified porous polymer according to any one of claims 1-8.

10. A lithium-ion electrode, characterized in that, The fluorinated modified porous polymer of claim 9 is prepared by using the fluorinated modified porous polymer as the negative electrode active material.

11. A lithium-ion battery, characterized in that, Includes the lithium-ion electrode as described in claim 10.

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