Conjugated porous organic polymer, method for preparing the same, and secondary battery

Abstract

The present application relates to the technical fields of polymer synthesis, in particular to a conjugated porous organic polymer, a preparation method thereof and a secondary battery, the preparation method of the conjugated porous organic polymer comprises the following steps: heat treating mixed powders of polycyclic aromatic hydrocarbon compounds and Lewis acid to obtain the conjugated porous organic polymer, the preparation method of the conjugated porous organic polymer provided by the present application is based on solid-phase Scholl coupling reaction, which avoids the use of a large amount of solvent, simplifies the preparation steps, and has a wide range of reactant applications, can effectively construct a porous polymer with a large conjugated skeleton, and ensures that the prepared conjugated porous organic polymer has high intrinsic porosity and electronic conductivity, and the conjugated porous organic polymer prepared by the preparation method has excellent capacity and rate performance as a negative active material of a secondary battery.

Description

Technical Field

[0001] This invention relates to the field of polymer synthesis technology, and in particular to a conjugated porous organic polymer, its preparation method, and a secondary battery. Background Technology

[0002] In recent decades, porous materials have been widely used in various fields such as energy storage and conversion, gas capture and storage, and photoelectrocatalysis, resulting in an explosive growth in their quantity. Besides natural porous materials, inorganic synthetic porous materials such as zeolites and inorganic-organic hybrid synthetic porous materials such as metal-organic frameworks (MOFs) have all achieved successful industrial applications and captured a certain market share.

[0003] Over the past two decades, a variety of porous organic polymer materials containing only organic components have been developed. Compared to inorganic porous materials and inorganic-organic porous polymer materials, organic porous polymer materials based on pure organic components retain the porous structure while exhibiting unique advantages such as low cost, absence of special elements, low toxicity, and environmental friendliness. Furthermore, organic materials have a unique advantage: their physicochemical properties can be further optimized by more easily controlling the intrinsic chemical structure and composition of the polymer through molecular engineering, thereby further promoting the industrial application of these materials.

[0004] Currently, numerous studies have reported on the applications of organic porous polymers in the electrochemical field. However, due to the relatively low electronic conductivity of organic materials, their performance in many applications is not ideal, hindering further development. For organic molecular materials, the electron transport performance is primarily determined by both intramolecular and intermolecular electron transport. For polymer molecules with long chain segments, efficient intramolecular electron transport is particularly important. Constructing large aromatic conjugated or even fully aromatic conjugated systems has proven to be an effective strategy for improving the overall electronic conductivity of organic materials by enhancing intramolecular electron transport. This strategy aims to reduce the molecular band gap, allowing electrons to more easily move from the HOMO to the LUMO level, and also utilizes the efficient movement of electrons within the large conjugated π bonds.

[0005] However, organic porous polymers with large conjugated systems generally employ aromatic coupling reactions in solvents, including Suzuki coupling and Heck coupling, to connect adjacent aromatic molecules, constructing intrinsic porous structures by utilizing the geometric properties of the aromatic molecules' functional groups. These aromatic coupling reactions in organic solvents mostly utilize catalysts based on palladium metal or palladium-coordinated cations, and are carried out under highly anhydrous and oxygen-free conditions. This type of method not only consumes large amounts of toxic and environmentally harmful organic solvents but also requires additional anhydrous and oxygen-free treatment of the solvent, making the preparation process more cumbersome. Furthermore, the reaction scale that can be carried out at one time is very limited, making it difficult to meet the goals of industrial production. Therefore, there is a need for an efficient and simple method for preparing organic porous polymers with large conjugated systems.

[0006] In view of this, this invention is hereby proposed. Summary of the Invention

[0007] The primary objective of this invention is to provide a method for preparing conjugated porous organic polymers based on solid-phase Scholl coupling reactions. This method avoids the use of large amounts of solvents, simplifies the preparation steps, and has a wide range of applicable reactants. It can effectively construct porous polymers with large conjugated skeletons, ensuring that the obtained conjugated porous organic polymers have high intrinsic porosity and electronic conductivity.

[0008] A second objective of this invention is to provide a conjugated porous organic polymer having a large conjugated framework structure, high intrinsic porosity, and high electronic conductivity.

[0009] A third objective of this invention is to provide a secondary battery with excellent capacity and rate performance.

[0010] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0011] This invention provides a method for preparing a conjugated porous organic polymer, comprising the following steps:

[0012] The conjugated porous organic polymer is obtained by heat-treating a mixed powder of polycyclic aromatic hydrocarbons and Lewis acids.

[0013] Furthermore, the polycyclic aromatic hydrocarbon compound includes at least one of anthraquinone, pentabenzoquinone, and tetraazapentabenzoquinone;

[0014] And / or, the Lewis acid includes at least one of ferric chloride, cobalt chloride, and cerium chloride.

[0015] Furthermore, the molar ratio of the polycyclic aromatic hydrocarbon compound to the Lewis acid is 1:(4-6).

[0016] Further, the polycyclic aromatic hydrocarbon compound and the Lewis acid are mixed and ground to obtain the mixed powder.

[0017] Furthermore, the heat treatment includes: heating to 400-450°C and holding at that temperature for 20-30 hours under an inert atmosphere.

[0018] Further, after the heat treatment, a crude product is obtained; the crude product is then post-treated to obtain the conjugated porous organic polymer.

[0019] The post-processing includes: adding dilute hydrochloric acid solution to the crude product, refluxing and stirring, washing with water until neutral, washing with solvent, and drying.

[0020] Further, the washing with a solvent includes: adding N,N-dimethylformamide, heating and stirring, and then washing with at least one of N,N-dimethylformamide, tetrahydrofuran, water and ethanol.

[0021] Furthermore, the drying process includes drying for more than 12 hours under conditions of vacuum degree less than 0.1 MPa and temperature of 80–100°C.

[0022] The present invention also provides a conjugated porous organic polymer, which is prepared by the method described above for preparing conjugated porous organic polymers.

[0023] The present invention also provides a secondary battery comprising the conjugated porous organic polymer as described above.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] 1. The method for preparing conjugated porous organic polymers provided by this invention is based on solid-phase Scholl coupling reaction, which avoids the use of a large amount of solvent, simplifies the preparation steps, can be adapted to a variety of reactants, and can realize large-scale industrial production.

[0026] 2. The preparation method of the conjugated porous organic polymer of the present invention can be carried out using conventional heat treatment equipment, and there are no special requirements for the equipment; moreover, the heat treatment temperature is relatively low, which saves energy and ensures that the reactants will not decompose at high temperature.

[0027] 3. The method for preparing conjugated porous organic polymers of the present invention can effectively polymerize small molecules with aromatic conjugated systems to form porous polymers with large or full conjugation, which exhibit good intrinsic porosity and electronic conductivity. When used as negative electrode materials for secondary batteries, they exhibit excellent capacity and rate performance. Attached Figure Description

[0028] 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 of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0029] Figure 1 This is a 5000x magnified SEM image of pPQ in Embodiment 2 of the present invention.

[0030] Figure 2 This is a 4000x magnified SEM image of pPQ in Embodiment 2 of the present invention.

[0031] Figure 3 The XRD patterns of AQ and pAQ in Embodiment 1 of the present invention are shown.

[0032] Figure 4 The XRD patterns of PQ and pPQ in Embodiment 2 of the present invention are shown.

[0033] Figure 5 The XRD patterns of TAPQ and pTAPQ in Embodiment 3 of the present invention are shown.

[0034] Figure 6 The infrared spectra of AQ and pAQ in Embodiment 1 of the present invention are shown.

[0035] Figure 7 The infrared spectra of PQ and pPQ in Embodiment 2 of the present invention are shown.

[0036] Figure 8 The infrared spectra of TAPQ and pTAPQ in Embodiment 3 of the present invention are shown.

[0037] Figure 9 The isothermal nitrogen adsorption curves (a) and semi-pore size distribution curves (b) of pAQ in Example 1 and pPQ in Example 2 of this invention are shown.

[0038] Figure 10 This invention presents the rate performance of the battery prepared using pPQ in Example 2 at different current densities. Detailed Implementation

[0039] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0040] The following describes in detail a conjugated porous organic polymer, its preparation method, and a secondary battery according to an embodiment of the present invention.

[0041] In some embodiments of the present invention, a method for preparing a conjugated porous organic polymer is provided, comprising the following steps:

[0042] A mixed powder of polycyclic aromatic hydrocarbons and Lewis acids was heat-treated to obtain a conjugated porous organic polymer.

[0043] The method for preparing conjugated porous organic polymers of the present invention is based on a solid-phase ionic thermal oxidative coupling reaction (Scholl coupling reaction) using a strong Lewis acid as a catalyst. It can directly construct carbon-carbon bonds on adjacent aromatic rings to connect adjacent reactants together, avoiding the use of large amounts of solvents 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.

[0044] The reactants of this invention have a wide range of applications, do not require specific functional groups on the reactants, and can be adapted to a variety of small molecules with aromatic structures, thus giving the reaction a great deal of freedom; the chemical composition of the final porous polymer product can be effectively controlled by the selection of small molecules, including controlling the pore structure and size distribution of the polymer by controlling the geometry of the small molecules, and achieving heteroatom doping of the final product by using small molecules containing heteroatoms, which is more convenient than traditional doping and modification methods.

[0045] In some embodiments of the present invention, the polycyclic aromatic hydrocarbon compound includes at least one of anthraquinone (AQ), pentaquinone (PQ), and tetraazapentaquinone (TAPQ).

[0046] The polycyclic aromatic hydrocarbon compound of the present invention is a derivative of linear polyacene and has a highly conjugated structure.

[0047] In some embodiments of the present invention, Lewis acids include, but are not limited to, at least one of ferric chloride, cobalt chloride, and cerium chloride.

[0048] In some embodiments of the invention, the molar ratio of the polycyclic aromatic hydrocarbon compound to the Lewis acid is 1:(4 to 6); typically, but not limitingly, for example, the molar ratio of the polycyclic aromatic hydrocarbon compound to the Lewis acid can be a range of 1:4, 1:5, 1:6, or any combination thereof.

[0049] In some embodiments of the present invention, polycyclic aromatic hydrocarbon compounds and Lewis acids are mixed and ground to obtain a mixed powder.

[0050] In some embodiments of the invention, the grinding process includes using a mortar and pestle.

[0051] In some embodiments of the present invention, the heat treatment includes: heating to 400–450°C and holding at that temperature for 20–30 hours in an inert atmosphere; typically, but not limitingly, for example, the temperature of the heat treatment can be a range of 400°C, 410°C, 420°C, 430°C, 440°C, 450°C, or any combination thereof; the time of the heat treatment can be a range of 20 hours, 22 hours, 24 hours, 26 hours, 28 hours, 30 hours, or any combination thereof.

[0052] The heat treatment of this invention is carried out at 400-450°C, which is much lower than the high temperature of over 600°C required for some solid-phase reactions. This saves energy and ensures that the special functional groups on the reactants do not decompose at high temperatures.

[0053] In some embodiments of the present invention, the inert atmosphere includes, but is not limited to, argon.

[0054] In some embodiments of the present invention, the heating rate of the heat treatment is 1 to 10 K / min.

[0055] In some embodiments of the present invention, the heat treatment includes: placing a container containing the mixed powder in a tube furnace for heat treatment; preferably, the container includes, but is not limited to, a corundum porcelain boat or a corundum crucible.

[0056] Solid-phase coupling reactions generally require sealing in a tube under high vacuum or high inertness conditions; however, this invention eliminates the need for sealing and allows the reaction to proceed using only a conventional heat treatment equipment, a tube furnace. Compared to the method of sealing in a tube, this invention is simpler and can accommodate more reactants in each reaction.

[0057] In some embodiments of the present invention, after heat treatment, a crude product is obtained; the crude product is then post-treated to obtain a conjugated porous organic polymer.

[0058] Post-processing includes: adding dilute hydrochloric acid solution to the crude product, refluxing and stirring, washing with water until neutral, washing with solvent, and drying.

[0059] In some embodiments of the present invention, a dilute hydrochloric acid solution is added to the crude product and refluxed and stirred for 10 to 15 hours.

[0060] In some embodiments of the present invention, washing with a solvent includes: adding N,N-dimethylformamide (DMF), heating and stirring, and then washing with at least one of N,N-dimethylformamide (DMF), tetrahydrofuran (THF), water and ethanol.

[0061] In some embodiments of the present invention, washing with a solvent includes: adding N,N-dimethylformamide (DMF) and stirring at 110-130°C for 4-15 hours, followed by rinsing with N,N-dimethylformamide (DMF), tetrahydrofuran (THF), water, and ethanol in sequence.

[0062] In some embodiments of the present invention, drying includes drying for more than 12 hours under conditions of vacuum degree less than 0.1 MPa and temperature of 80-100°C.

[0063] In some embodiments of the present invention, a conjugated porous organic polymer is also provided, which is prepared by the above-described method for preparing the conjugated porous organic polymer.

[0064] The conjugated porous organic polymer prepared by the method of the present invention has a large conjugated framework structure, high intrinsic porosity and electronic conductivity.

[0065] In some embodiments of the present invention, a secondary battery is also provided, comprising the above-mentioned conjugated porous organic polymer.

[0066] In some embodiments of the present invention, the secondary battery includes a lithium-ion battery.

[0067] The conjugated porous organic polymer prepared by the above-mentioned method exhibits good intrinsic porosity and electronic conductivity. When used as a negative electrode material for secondary batteries, it shows excellent capacity and rate performance.

[0068] Example 1

[0069] The method for preparing the conjugated porous organic polymer pAQ provided in this embodiment includes the following steps:

[0070] AQ (2.08 g, 10 mmol) and ferric chloride (8.1 g, 50 mmol) were ground and mixed evenly in a mortar to obtain a mixed powder.

[0071] The mixed powder was then 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 outlet of the tube furnace, and the vacuum was evacuated to a pressure below 0.1 MPa. Argon gas was then introduced until the pressure inside the tube furnace reached atmospheric pressure. The above evacuation and gas exchange 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. The product was then cooled to room temperature.

[0072] After the tube furnace cooled to room temperature, the corundum ceramic boat was removed, and the crude product powder was poured into a dilute hydrochloric acid solution. The solution was heated to reflux and stirred under reflux for 12 hours. The mixture was then filtered to obtain a solid powder. The solid powder was washed with deionized water until neutral and then poured into DMF and heated to 120°C and stirred for 12 hours. The mixture was then filtered while hot to obtain a filter cake. The filter cake was washed sequentially with DMF, THF, water, and ethanol at room temperature. The product pAQ was then placed in a vacuum drying oven at 80°C and dried at a vacuum of less than 0.1 MPa for more than 12 hours to obtain the product pAQ.

[0073] Example 2

[0074] The synthetic route for the conjugated porous organic polymer pPQ provided in this embodiment is as follows:

[0075]

[0076] The preparation method of the conjugated porous organic polymer pPQ provided in this embodiment is the same as that in Example 1, except that 10 mmol of AQ is replaced with 10 mmol of PQ.

[0077] Example 3

[0078] The preparation method of the conjugated porous organic polymer pTAPQ provided in this embodiment is the same as in Example 1, except that 10 mmol of AQ is replaced with 10 mmol of TAPQ.

[0079] Experimental Example 1

[0080] The pPQ prepared in Example 2 was subjected to scanning electron microscopy, and the results are as follows: Figure 1 and Figure 2 As shown. Figure 1 This is a 5000x magnified SEM image of pPQ in Example 2; Figure 2 This is a 3000x magnified SEM image of pPQ in Example 2.

[0081] X-ray diffraction (XRD) tests were performed on AQ and pAQ in Example 1, PQ and pPQ in Example 2, and TAPQ and pTAPQ in Example 3. The results are as follows: Figure 3 , Figure 4 and Figure 5As shown.

[0082] from Figure 3 , Figure 4 and Figure 5 It can be seen that the three reactant molecules AQ, PQ, and TAPQ exhibit obvious diffraction peaks, showing a long-range ordered structure. The XRD patterns of the products pAQ, pPQ, and pTAPQ obtained after heat treatment do 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.

[0083] Infrared spectroscopy tests were performed on AQ and pAQ in Example 1, PQ and pPQ in Example 2, and TAPQ and pTAPQ in Example 3. The results are as follows: Figure 6 , Figure 7 and Figure 8 As shown.

[0084] from Figure 6 , Figure 7 and Figure 8 It can be seen from the infrared spectroscopy results that the conjugated porous organic polymers pAQ, pPQ, and pTAPQ show similar performance at 1750 cm⁻¹. -1 An absorption peak is observed at 1060 cm⁻¹, corresponding to a carbon-carbon double bond absorption peak, indicating that the aromatic structure of the small molecules of the reactants was preserved after polymerization via heat treatment solid-state reaction; furthermore, the pTAPQ infrared spectrum shows an absorption peak at 1060 cm⁻¹. -1 The presence of additional absorption peaks at the location corresponds to the carbon-nitrogen bond signal, demonstrating that the preparation method of the present invention can effectively prepare doped porous polymer materials by using small reactant molecules containing heteroatoms.

[0085] Four-probe electrical tests were performed on pAQ, pPQ, and pTAPQ from Examples 1 to 3, as well as pTOC-250, 3D p-POP, SP-BTT, 1-Te, Sp2c-COF, BUCT-COF-1, and BUCT-COF-4, to obtain the electronic conductivity of the porous polymer powders. The results are recorded in Table 1.

[0086] For pTOC-250, see: Fritz, PW; Chen, T.; Ashirov, T.; Nguyen, A.; M.; Coskun, A.Fully Conjugated Tetraoxa[8]Circulene-Based Porous SemiconductingPolymers.Angewandte Chemie 2022,134(17),e202116527.

[0087] 3D p-POP See: Byun, Y.; Xie, L.S.; Fritz, P.; Ashirov, T.; M.; Coskun, A. A Three-Dimensional Porous Organic Semiconductor Based on Fully Sp2-Hybridized Graphitic Polymer. Angewandte Chemie 2020, 132(35), 15278–15282.

[0088] SP-BTT See: Kochergin, Y.S.; Noda, Y.; Kulkarni, R.; K.; Tarábek, J.; Schmidt, J.; Bojdys, M.J. Sulfur-and Nitrogen-Containing Porous Donor-Acceptor Polymers as Real-Time Optical and Chemical Sensors. Macromolecules 2019, 52(20), 7696-7703.

[0089] 1-Te See: Duhovic, S.; Dinca, M. Synthesis and Electrical Properties of Covalent Organic Frameworks with Heavy Chalcogens. Chemistry of Materials 2015, 27(16), 5487-5490.

[0090] Sp2c-COF See: Jin, E.; Asada, M.; Xu, Q.; Dalapati, S.; Addicoat, M.A.; Brady, M.A.; Xu, H.; Nakamura, T.; Heine, T.; Chen, Q. Two-Dimensional Sp2 Carbon-Conjugated Covalent Organic Frameworks. Science 2017, 357(6352), 673-676.

[0091] BUCT-COF-1 See: Wang, S.; Da, L.; Hao, J.; Li, J.; Wang, M.; Huang, Y.; Li, Z.; Liu, Z.; Cao, DA Fully Conjugated 3D Covalent Organic Framework Exhibiting Band-like Transport with Ultrahigh Electron Mobility. Angewandte ChemieInternational Edition 2021,60(17),9321-9325.

[0092] BUCT-COF-4 see: Wang, S.; Li,

[0093] Table 1

[0094] Porous polymers <![CDATA[Electronic conductivity (S cm -1 )]]> pAQ <![CDATA[3.35×10 -2 ]]> pPQ <![CDATA[9.12×10 -2 ]]> pTAPQ <![CDATA[3.57×10 -2 ]]> pTOC-250 <![CDATA[5.0×10 -8 ]]> 3D p-POP <![CDATA[4.2×10 -9 <!-- 6 -->]]> SP-BTT <![CDATA[1.31×10 -7 ]]> 1-Te <![CDATA[6.1×10 -16 ]]> Sp2c-COF <![CDATA[1.6×10 -7 ]]> BUCT-COF-1 <![CDATA[5.8×10 -8 ]]> BUCT-COF-4 <![CDATA[5.0×10 -8 ]]>

[0095] As can be seen from Table 1, pAQ, pPQ, and pTAPQ all have a value greater than 1×10⁻⁶. -2 S cm -1 Its electronic conductivity exceeds that of most organic porous polymers, which greatly promotes the electrochemical application of the product.

[0096] Nitrogen isothermal adsorption / desorption tests were conducted on pAQ of Example 1 and pPQ of 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 9 As shown.

[0097] from Figure 9 It can be seen that the specific surface area of ​​pAQ and pPQ is 1046 m². 2 g -1 and 1429m 2 g -1 This demonstrates the high porosity within the material; furthermore, the pore size and radius of pAQ and pPQ are mainly distributed in... Within this range, most of the pores are micropores.

[0098] Tests on internal pore size and electrical conductivity demonstrate that this invention successfully synthesizes a polymer material that combines high electrical conductivity and internal porosity.

[0099] Experimental Example 2

[0100] A battery was fabricated using pPQ obtained in Example 2 as the negative electrode active material. The performance of the battery was tested, and the results are as follows: Figure 10 As shown.

[0101] 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.

[0102] 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. Then, pressure is applied to fasten the battery case tightly. The electrolyte is a commercially available lithium battery electrolyte with a composition of ethylene carbonate: diethyl carbonate = 1:1 (volume ratio) 1 mole per liter lithium hexafluorophosphate solution. The separator is a commercially available polypropylene separator. After assembly, the battery is left to stand for 10 hours before electrochemical testing.

[0103] The battery was installed on the Xinwei Electrochemical Cyclic Tester (manufacturer: Shenzhen Xinwei Battery Testing Equipment Co., Ltd., product model: BTS-4000 Power Battery Testing System) to test the lithium-ion storage capacity under different currents.

[0104] from Figure 10 It can be seen that the negative electrode based on pPQ at 50mA g -1 It exhibited a current density exceeding 800 mAh g -1 Its lithium storage capacity is far higher than that of graphite, the most commonly used commercial carbon-based anode material. At a high current density of 2000 mA g / g... -1 The pPQ displays a capacity exceeding 500mAh g. -1 The porous polymer prepared by the method of the present invention exhibits excellent rate performance, which is mainly due to its intrinsic porosity and electronic conductivity.

[0105] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A negative electrode active material for a secondary battery, characterized in that, The negative electrode active material is a conjugated porous organic polymer, and the preparation method of the conjugated porous organic polymer includes the following steps: The conjugated porous organic polymer is obtained by heat-treating a mixed powder of polycyclic aromatic hydrocarbons and Lewis acids. The polycyclic aromatic hydrocarbon compound includes at least one of anthraquinone, pentabenzoquinone, and tetraazapentabenzoquinone; The molar ratio of the polycyclic aromatic hydrocarbon compound to the Lewis acid is 1:(4~6). The heat treatment includes: heating to 400~450℃ and holding for 20~30 hours under an inert atmosphere.

2. The negative electrode active material of the secondary battery according to claim 1, characterized in that, The Lewis acid includes at least one of ferric chloride, cobalt chloride, and cerium chloride.

3. The negative electrode active material of the secondary battery according to claim 1, characterized in that, The polycyclic aromatic hydrocarbon compound and the Lewis acid are mixed and ground to obtain the mixed powder.

4. The negative electrode active material of the secondary battery according to claim 1, characterized in that, After the heat treatment, a crude product is obtained; the crude product is then post-treated to obtain the conjugated porous organic polymer. The post-processing includes: adding dilute hydrochloric acid solution to the crude product, refluxing and stirring, washing with water until neutral, washing with solvent, and drying.

5. The negative electrode active material of the secondary battery according to claim 4, characterized in that, The washing with solvent includes: adding N,N-dimethylformamide, heating and stirring, and then washing with at least one of N,N-dimethylformamide, tetrahydrofuran, water and ethanol.

6. The negative electrode active material of the secondary battery according to claim 4, characterized in that, The drying process includes: drying under a vacuum of less than 0.1 MPa at a temperature of 80-100 °C. o Dry at C for more than 12 hours.

7. A secondary battery, characterized in that, Includes the negative electrode active material of the secondary battery according to any one of claims 1 to 6.

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