Polymer lithium ion battery and preparation method

Abstract

The application relates to a polymer lithium ion battery and a preparation method, wherein a composite material POP-CTF-X-P / PCT with small molecule gas adsorption function and flame retardant function is introduced into the positive and negative electrodes of the battery, the flame retardant function of the positive and negative electrodes is improved, the safety of the lithium ion battery is improved, a polymer monomer solution is prepared, an electrolyte is formed through in-situ polymerization, an electrochemically stable and mechanically stable polymer electrolyte is constructed in-situ, the interface impedance of the polymer lithium ion battery is reduced, and the stability of the polymer lithium ion battery system is improved.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery technology, and in particular relates to a polymer lithium-ion battery and its preparation method. Background Technology

[0002] With the rapid development of electronic technology, lithium-ion batteries, as traditional energy storage devices, are facing increasing demands for energy density, which poses a growing challenge to their safety performance.

[0003] When lithium-ion batteries are stored or used for extended periods under extreme or abnormal environmental conditions, the active materials react with the electrolyte. The electrolyte undergoes oxidation at the positive electrode and reduction at the negative electrode. These oxidation-reduction reactions produce various small-molecule gases, primarily including CO, CH4, CO2, C2H4, C2H6, C3H6, C3H8, and SO2. This gas production can cause severe battery deformation and even lead to battery casing rupture. Furthermore, CO, CH4, C2H4, C2H6, C3H6, and C3H8 are highly flammable and pose potential safety hazards to lithium-ion batteries.

[0004] Currently, the electrolytes commonly used in lithium-ion batteries are flammable, explosive, and volatile organic solvents. Leakage of these electrolytes can pose safety hazards. In contrast, polymer electrolytes are leak-proof, avoiding safety accidents caused by electrolyte leaks. Therefore, polymer lithium-ion batteries represent an important direction in the development of lithium-ion batteries. Polymer electrolyte materials can be prepared in situ, are easy to integrate into manufacturing processes, and possess good interfacial stability, thus improving the safety of lithium-ion batteries. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a polymer lithium-ion battery and its preparation method.

[0006] The technical solution adopted in this invention is: a composite material, which is obtained by pyrolyzing and carbonizing POP-CTF-X, a porous organic polymer with a covalent triazine skeleton, to obtain POP-CTF-XP, and then combining it with hexachlorocyclotriphosphazene to obtain a POP-CTF-XP / PCT composite material.

[0007] Preferably, a mixture of terephthalonitrile and biphenylnitrile is used as a monomer, which is mixed with zinc chloride and reacted under high temperature and high pressure to obtain POP-CTF. After treatment with hydrochloric acid, POP-CTF-X is obtained. After pyrolysis and crushing, POP-CTF-XP is obtained. POP-CTF-XP is added to PCT methanol solution for aging and then composited under high temperature to obtain POP-CTF-XP / PCT composite material.

[0008] A polymer lithium-ion battery, wherein the positive electrode and / or negative electrode contain a POP-CTF-XP / PCT composite material.

[0009] Preferably, the components of the battery cathode material include 90%-98% cathode active material, 0.5%-5% conductive agent, 1%-3% binder, 0.5%-5% POP-CTF-XP / PCT and 0.5%-2% PCT;

[0010] The raw material components for preparing the battery negative electrode include 90%-98% negative electrode active material, 0.5%-5% conductive agent, 1%-3% binder, and 0.5%-5% POP-CTF-XP / PCT and 0.5%-2% PCT.

[0011] Preferably, the polymer electrolyte is an in-situ polymerized electrolyte;

[0012] Preferably, it is obtained by in-situ polymerization of polymer monomer solution, wherein the polymer monomer solution components include 0.2%-10% comonomer one, 0.2%-10% comonomer two, 10%-40% lithium salt, 0.01%-1% initiator and 50%-88% small molecule solvent.

[0013] Preferably, the comonomer one is one or a combination of triallyl isocyanurate, dipentaerythritol triacrylate, dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate;

[0014] Comonomer 2 is one or more of the following: trifluoroethyl methacrylate, perfluoroalkyl ethyl acrylate, tetrafluoropropyl methacrylate, hexafluorobutyl methacrylate, 3-methacryloyloxypropylmethyldimethoxysilane, and vinyl-tris(methylethyl ketoxime)silane.

[0015] Preferably, the lithium salt is one or a combination of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), and lithium hexafluoroarsenate (LiAsF6);

[0016] The initiator is one or both of benzoyl peroxide and azobisisobutyronitrile;

[0017] The small molecule solvent is one or a combination of PC, EMC, DMC, EC, DEC, FEC, AN, SN, VC, VEC, PS, PES, and DTD.

[0018] The method for preparing polymer lithium-ion batteries involves first preparing a positive electrode and a negative electrode, which are composed of POP-CTF-XP / PCT composite materials, respectively. These are then assembled with a separator to form a dry cell. After injecting a polymer monomer solution, the electrolyte is polymerized in situ to form the electrolyte. Finally, the polymer lithium-ion battery is prepared.

[0019] Preferably, the specific method is as follows:

[0020] Step 1: Using a mixture of terephthalonitrile and biphenylnitrile as monomers, mix with zinc chloride and heat at 450-600℃ for 10-48h to obtain POP-CTF solution. Treat with hydrochloric acid solution at 80℃ and deionized water at 100℃ to obtain POP-CTF-X. POP-CTF-X is then pyrolyzed at 700-1500℃, cooled, and crushed to obtain pyrolytic POP-CTF-XP.

[0021] Step 2: Dissolve hexachlorocyclotriphosphazene in methanol to prepare a PCT / methanol solution with a mass fraction of 1%-20%. Add POP-CTF-XP to the PCT / methanol solution and age it fully at 40-60℃ for 12-72 hours. After filtration, dry it under vacuum at 100℃ and age it in an inert gas atmosphere tube furnace at 200-300℃ for 2-24 hours to obtain the POP-CTF-XP / PCT composite material.

[0022] Step 3: Homogenize the positive and negative electrode slurries using NMP as a solvent. The positive electrode slurry comprises 90%-98% positive active material, 0.5%-5% conductive agent, 1%-3% binder, 0.5%-5% POP-CTF-XP / PCT, and 0.5%-2% PCT. The negative electrode slurry comprises 90%-98% negative active material, 0.5%-5% conductive agent, 1%-3% binder, 0.5%-5% POP-CTF-XP / PCT, and 0.5%-2% PCT. After homogenization, coat the slurries to obtain positive and negative electrode sheets. Assemble the positive and negative electrode sheets into a lithium-ion battery dry cell.

[0023] Step 4: Prepare a polymer monomer solution, specifically including 0.2%-10% comonomer one, 0.2%-10% comonomer two, 10%-40% lithium salt, 0.01%-1% initiator, and 50%-88% small molecule solvent;

[0024] Step 5: Inject the polymer monomer solution into the lithium-ion battery dry cell for 6-36 hours for aging and in-situ polymerization reaction, and form at 40-90℃ and 0.3-1.3MPa to obtain the polymer lithium-ion battery.

[0025] The advantages and positive effects of this invention are as follows: Adding the POP-CTF-XP / PCT composite material to the positive and negative electrode sheets of the battery enables the positive and negative electrode sheets to adsorb small molecule gases; the introduction of PCT material enhances the flame retardant function of the positive and negative electrodes, adsorbing flammable (alkanes, olefins, CO, etc.) and harmful small gas molecules (CO2, SO2, etc.) during operation, thereby improving flame retardant performance, suppressing battery gas production, and enhancing the safety performance of the polymer lithium-ion battery; furthermore, by constructing an electrochemically stable and mechanically stable polymer electrolyte in situ, the polymer battery is integrated into the manufacturing process, reducing the interfacial impedance of the polymer battery and improving the stability of the high-energy-density flexible lithium-ion battery system. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the molecular structure of POP-CTF-X of the present invention;

[0027] Figure 2 This is a schematic diagram of the porous structure of POP-CTF-XP / PCT. Detailed Implementation

[0028] The embodiments of the present invention will now be described with reference to the accompanying drawings.

[0029] This invention relates to a polymer lithium-ion battery and its preparation method. First, flame-retardant positive / negative electrode sheets with small molecule gas adsorption function are prepared and assembled with other lithium-ion battery components to obtain a dry cell. Then, a polymer monomer solution is added, followed by in-situ polymerization to prepare the polymer lithium-ion battery. Adding a POP-CTF-XP / PCT composite material with both small molecule gas adsorption and flame-retardant functions to the positive and negative electrodes of the battery improves the adsorption of harmful small molecule gases and enhances its flame-retardant performance.

[0030] The POP-CTF-XP / PCT composite material is obtained by combining POP-CTF-X, a covalent triazine framework (CTF) porous organic polymer (POPs), with POP-CTF-X obtained by high-temperature pyrolysis carbonization in a high-pressure reactor, and hexachlorocyclotriphosphazene (PCT). The POP-CTF-XP / PCT composite material can be added to the raw material components for preparing the positive and negative electrode slurries of batteries. The raw material components for preparing the positive electrode include 90%-98% positive electrode active material, 0.5%-5% conductive agent, 1%-3% binder, 0.5%-5% POP-CTF-XP / PCT, and 0.5%-2% PCT; the raw material components for preparing the negative electrode include 90%-98% negative electrode active material, 0.5%-5% conductive agent, 1%-3% binder, 0.5%-5% POP-CTF-XP / PCT, and 0.5%-2% PCT. The positive electrode active material is one or a mixture of more than one of ternary cathode materials, lithium cobalt oxide, lithium iron phosphate, and lithium manganese iron phosphate; the negative electrode active material is one or a mixture of two or more of graphite, carbon materials, and silicon anode materials; the conductive agent is CNT or carbon black, etc.; the binder added to the positive electrode slurry can be PVDF; the binder added to the negative electrode slurry can be PAA, PI, SBR, or CMC, etc. The various components are mixed to prepare the positive electrode slurry and the negative electrode slurry, which are then coated to obtain the battery positive electrode sheet and the battery negative electrode sheet, respectively.

[0031] The battery electrolyte is an electrolyte obtained by in-situ polymerization of polymer monomer solution. The polymer monomer solution components include 0.2%-10% comonomer I, 0.2%-10% comonomer II, 10%-40% lithium salt, 0.01%-1% initiator, and 50%-88% small molecule solvent. Comonomer 1 is one or more of triallyl isocyanurate, dipentaerythritol triacrylate, dipentaerythritol pentaacrylate, and dipentaerythritol hexaacrylate; comonomer 2 is one or more of trifluoroethyl methacrylate, perfluoroalkyl ethyl acrylate, tetrafluoropropyl methacrylate, hexafluorobutyl methacrylate, 3-methacryloyloxypropylmethyldimethoxysilane, and vinyl-tris(methylethyl ketoxime)silane; lithium salt is one or more of lithium bis(trifluoromethanesulfonylimide)LiTFSI, lithium hexafluorophosphate LiPF6, lithium tetrafluoroborate LiBF4, and lithium hexafluoroarsenate LiAsF6; initiator is one or more of benzoyl peroxide and azobisisobutyronitrile; small molecule solvent is one or more of PC, EMC, DMC, EC, DEC, FEC, AN, SN, VC, VEC, PS, PES, and DTD.

[0032] In some embodiments of the present invention, the preparation method of the POP-CTF-XP / PCT composite material is as follows:

[0033] Step 1: Preparation of covalent triazine framework (CTF) porous organic polymers (POPs); using a mixture of terephthalonitrile and biphenylnitrile as monomers, the mixture was uniformly mixed with zinc chloride and placed in a stainless steel reactor. After heating at 450-600℃ for 10-48 hours, the mixture was removed, cooled, and a POP-CTF solution was obtained. After treatment with hydrochloric acid solution at 80℃ and subsequently with deionized water at 100℃, the solution was filtered and dried to obtain pure POP-CTF-X, the structure of which is shown below. Figure 1 As shown; POP-CTF-X is further heated and pyrolyzed at 700-1500℃, cooled and crushed to obtain pyrolyzed (POP-CTF-XP) material, which is then sieved, graded and ready for use;

[0034] Step 2: Preparation of POP-CTF-XP / PCT composite material; Dissolve hexachlorocyclotriphosphazene (PCT) in methanol to prepare a 1%-20% (w / w) PCT / methanol solution; Add POP-CTF-XP to the PCT / methanol solution, stir thoroughly at 40-60℃ to obtain the POP-CTF-XP / PCT / methanol solution, age thoroughly at 40-60℃ for 12-72 hours, filter, vacuum dry at 100℃, and age in an inert gas atmosphere tube furnace at 200-300℃ for 2-24 hours to obtain pure POP-CTF-XP / PCT composite material, with the structure as shown in the figure. Figure 2 As shown.

[0035] The prepared composite material, POP-CTF-XP, has a porous structure and a large specific surface area, and has the ability to adsorb small molecule gases. The flame retardant function of the positive and negative electrodes is enhanced by PCT material. The POP-CTF-XP / PCT composite material has both small molecule gas adsorption and flame retardant functions. At the same time, the carbonized POP-CTF-XP has electrical conductivity, which ensures the conductivity of the electrode.

[0036] Furthermore, the POP-CTF-XP / PCT composite material was used to prepare polymer lithium-ion batteries, and the steps are as follows:

[0037] Step 3: Preparation of positive and negative electrode sheets and dry cell for lithium-ion batteries; Positive and negative electrode slurries are homogenized using NMP as a solvent. The positive electrode components include positive electrode active material, conductive agent, binder, POP-CTF-XP / PCT, and PCT, with preferred proportions of 90%-98%, 0.5%-5%, 1%-3%, 0.5%-5%, and 0.5%-2%, respectively. The negative electrode components include negative electrode active material, conductive agent, binder, and POP-CTF-XP / PCT and PCT, with preferred proportions of 90%-98%, 0.5%-5%, 1%-3%, 0.5%-5%, and 0.5%-2%, respectively. After homogenization, the positive and negative electrode sheets are coated to obtain lithium-ion battery positive and negative electrode sheets. The positive and negative electrode sheets and separator are assembled into a lithium-ion battery dry cell through an assembly process.

[0038] Step 4: Preparation of in-situ polymerized electrolyte monomer solution, specifically including 0.2%-10% comonomer one, 0.2%-10% comonomer two, 10%-40% lithium salt, 0.01%-1% initiator, and 50%-88% small molecule solvent; using two comonomers, comonomer one is used as a crosslinking agent to undergo a polymerization reaction with comonomer two to form a crosslinked polymer network structure. In addition, comonomer one contains hydroxyl groups, which form hydrogen bonds with the POP-CTF-XP / PCT composite material and PCT material in the positive and negative electrode materials, thereby improving the stability of the polymer structure and battery system.

[0039] Step 5: In-situ polymerization and integrated polymer battery preparation; the polymer monomer solution is injected into the dry cell for 6-36 hours for aging and in-situ polymerization reaction; then, formation is carried out at 40-90℃ and 0.3-1.3MPa to complete the integrated preparation of the polymer battery.

[0040] By constructing electrochemically and mechanically stable polymer electrolytes in situ, the interfacial impedance of polymer lithium-ion batteries is reduced, thereby improving the stability and safety performance of polymer lithium-ion battery systems.

[0041] The present invention will now be described with reference to the accompanying drawings. Experimental methods not specifically described in terms of operation steps are performed in accordance with the corresponding product manuals. Unless otherwise specified, the instruments, reagents, and consumables used in the embodiments can be purchased from commercial companies.

[0042] Example 1

[0043] The first step was the preparation of POP-CTF-XP material. A mixture of terephthalonitrile and biphenylnitrile (mass ratio 1:1) was used as the monomer, and mixed uniformly with 200g of zinc chloride. The mixture was placed in a stainless steel reactor and heated at 450℃ for 24 hours. After cooling, a POP-CTF solution was obtained. This solution was then treated with hydrochloric acid solution at 80℃ and subsequently with deionized water at 100℃, filtered, and dried to obtain pure POP-CTF-X. POP-CTF-X was further pyrolyzed at 1000℃, cooled, and crushed to obtain pyrolyzed (POP-CTF-XP) material, which was then sieved and graded for later use.

[0044] The second step is the preparation of the POP-CTF-XP / PCT composite material. Hexachlorocyclotriphosphazene (PCT) was dissolved in methanol to prepare a 5% (w / w) PCT / methanol solution. POP-CTF-XP was added to the PCT / methanol solution, and the mixture was stirred thoroughly at 40°C to obtain the POP-CTF-XP / PCT / methanol solution. The solution was then aged at 60°C for 24 hours, filtered, vacuum dried at 100°C, and aged in an argon-atmosphere tube furnace at 200°C for 6 hours to obtain the pure POP-CTF-XP / PCT composite material.

[0045] The third step involves the preparation of the positive and negative electrode sheets and the dry cell for lithium-ion batteries. The positive and negative electrode slurries are homogenized using NMP as a solvent. The positive electrode components include a ternary cathode (70% Ni), CNT, PVDF, POP-CTF-XP / PCT, and PCT, with preferred proportions of 95%, 1%, 1.5%, 1.5%, and 1%, respectively. The negative electrode components include graphite, carbon black, PAA, and POP-CTF-XP / PCT and PCT, with preferred proportions of 95%, 0.5%, 2%, 1.5%, and 1%, respectively. The homogenized slurries are then coated to obtain the positive and negative electrode sheets for lithium-ion batteries. The positive and negative electrode sheets, along with the separator, are then assembled into a dry cell for lithium-ion batteries through an assembly process.

[0046] The fourth step is the preparation of the in-situ polymer electrolyte monomer solution. The weight percentages of dipentaerythritol hexaacrylate, perfluoroalkyl ethyl acrylate, LiTFSI, azobisisobutyronitrile, EMC, PC, DEC, FEC, PS, VEC, and SN in the polymer monomer solution are 1%, 3%, 12%, 0.05%, 30%, 10%, 30%, 10%, 0.95%, 2%, and 2%, respectively.

[0047] The fifth step is in-situ polymerization and integrated polymer battery fabrication. The polymer monomer solution is injected into a dry battery cell and aged at 45°C for 24 hours to carry out an in-situ polymerization reaction. Then, formation is performed at 60°C and 0.8 MPa to complete the integrated polymer battery fabrication.

[0048] Example 2

[0049] The first step was the preparation of POP-CTF-XP material. A mixture of terephthalonitrile and biphenylnitrile (mass ratio 2:8) was used as the monomer, and mixed uniformly with 200g of zinc chloride. The mixture was placed in a stainless steel reactor and heated at 450℃ for 24 hours. After cooling, a POP-CTF solution was obtained. This solution was then treated with hydrochloric acid solution at 80℃ and subsequently with deionized water at 100℃, followed by filtration and drying to obtain pure POP-CTF-X. POP-CTF-X was further pyrolyzed at 1000℃, cooled, and crushed to obtain pyrolyzed (POP-CTF-XP) material, which was then sieved and graded for later use.

[0050] The second step is the preparation of the POP-CTF-XP / PCT composite material. Hexachlorocyclotriphosphazene (PCT) was dissolved in methanol to prepare a 10% (w / w) PCT / methanol solution. POP-CTF-XP was added to the PCT / methanol solution, and the mixture was stirred thoroughly at 40°C to obtain the POP-CTF-XP / PCT / methanol solution. The solution was then aged at 60°C for 24 hours, filtered, vacuum dried at 100°C, and aged in an argon-atmosphere tube furnace at 200°C for 10 hours to obtain the pure POP-CTF-XP / PCT composite material.

[0051] The third step involves the preparation of the positive and negative electrode sheets and the dry cell for lithium-ion batteries. The positive and negative electrode slurries are homogenized using NMP as a solvent. The positive electrode components include a ternary cathode (70% Ni), CNTs, PVDF, POP-CTF-XP / PCT, and PCT, with preferred proportions of 95.5%, 1%, 1%, 1.5%, and 1%, respectively. The negative electrode components include graphite / silicon (8:2 mass ratio), carbon black, PAA, and POP-CTF-XP / PCT and PCT, with preferred proportions of 95.5%, 0.5%, 2%, 1.5%, and 0.5%, respectively. The homogenized slurries are then coated to obtain the positive and negative electrode sheets for lithium-ion batteries. The positive and negative electrode sheets, along with the separator, are then assembled into a lithium-ion battery dry cell through an assembly process.

[0052] The fourth step is the preparation of the in-situ polymerization electrolyte monomer solution. The weight percentages of dipentaerythritol tetraacrylate, 3-methacryloyloxypropylmethyldimethoxysilane, LiPF6, azobisisobutyronitrile, EMC, PC, DEC, FEC, PES, VC, and SN in the polymer monomer solution are 2%, 1%, 12%, 0.05%, 30%, 10%, 30%, 10%, 0.95%, 2%, and 2%, respectively.

[0053] The fifth step is in-situ polymerization and integrated polymer battery fabrication. The polymer monomer solution is injected into a dry battery cell and aged at 45°C for 24 hours to carry out an in-situ polymerization reaction. Then, formation is performed at 60°C and 0.8 MPa to complete the integrated polymer battery fabrication.

[0054] Example 3

[0055] Step 1: Preparation of POP-CTF-XP material. A mixture of terephthalonitrile and biphenylnitrile (mass ratio 8:2) was used as the monomer, and mixed uniformly with 200g of zinc chloride. The mixture was placed in a stainless steel reactor and heated at 450℃ for 24 hours. After cooling, a POP-CTF solution was obtained. This solution was then treated with hydrochloric acid solution at 80℃ and subsequently with deionized water at 100℃, followed by filtration and drying to obtain pure POP-CTF-X. POP-CTF-X was further pyrolyzed at 1000℃, cooled, and crushed to obtain pyrolyzed (POP-CTF-XP) material, which was then sieved and graded for later use.

[0056] The second step involves the preparation of the POP-CTF-XP / PCT composite material. Hexachlorocyclotriphosphazene (PCT) was dissolved in methanol to prepare a 15% (w / w) PCT / methanol solution. POP-CTF-XP was added to the PCT / methanol solution, and the mixture was stirred thoroughly at 40°C to obtain the POP-CTF-XP / PCT / methanol solution. The solution was then aged at 60°C for 24 hours, filtered, vacuum dried at 100°C, and aged in an argon-atmosphere tube furnace at 200°C for 10 hours to obtain the pure POP-CTF-XP / PCT composite material.

[0057] The third step involves the preparation of the positive and negative electrode sheets and the dry cell for lithium-ion batteries. The positive and negative electrode slurries are homogenized using NMP as a solvent. The positive electrode components include ternary cathode (80% Ni) / lithium manganese iron phosphate (5:5 mass ratio), CNT, PVDF, POP-CTF-XP / PCT, and PCT, with preferred proportions of 95.5%, 1%, 1%, 1.5%, and 1%, respectively. The negative electrode components include graphite, carbon black, PAA, and POP-CTF-XP / PCT and PCT, with preferred proportions of 95.5%, 0.5%, 2%, 1.5%, and 0.5%, respectively. The homogenized slurries are then coated to obtain the positive and negative electrode sheets for lithium-ion batteries. The positive and negative electrode sheets, along with the separator, are then assembled into a lithium-ion battery dry cell through an assembly process.

[0058] The fourth step is the preparation of the in-situ polymerization electrolyte monomer solution. The weight percentages of dipentaerythritol triacrylate, triallyl isocyanurate, perfluoroalkyl ethyl acrylate, LiPF6, azobisisobutyronitrile, EMC, PC, DEC, FEC, PES, VEC, and AN in the polymer monomer solution are 1%, 1%, 1%, 12%, 0.05%, 30%, 10%, 30%, 10%, 0.95%, 2%, and 2%, respectively.

[0059] The fifth step is in-situ polymerization and integrated polymer battery fabrication. The polymer monomer solution is injected into a dry battery cell and aged at 45°C for 24 hours to carry out an in-situ polymerization reaction. Then, formation is performed at 60°C and 0.8 MPa to complete the integrated polymer battery fabrication.

[0060] Example 4:

[0061] The specific surface area and small molecule adsorption capacity of the POP-CTF-XP / PCT prepared in Examples 1-3 were tested respectively.

[0062] The gas adsorption isotherms of the material at 298 K were tested using an Autosorb-iQ-MP fully automated specific surface area and pore size analyzer. A circulating cooling water bath method was used to control the temperature at 298 K. Before testing, the material sample was degassed overnight under vacuum at 423 K to remove moisture and other impurities. Adsorption isotherms for CO2, CH4, C3H8, C3H6, C2H6, and C2H4 were collected at 298 K. High-purity gases (99.9% or higher) were used: N2 99.999%, CO2 99.999%, CH4 99.999%, C3H8 99.9%, C3H6 99.9%, C2H6 99.9%, and C2H4 99.9%.

[0063] The specific surface area and pore size distribution of various porous materials were measured using an Autosorb-iQ-MP fully automated specific surface area and pore size analyzer at 77 K via an N2 adsorption isotherm. Based on sample stability, the samples were degassed overnight within acceptable limits before testing. The pore size distribution and micropore surface area were determined using the nonlocal density function theory (NLDFT) method. The results are shown in Table 1. The data in the table show that the composite materials prepared in Examples 1-3 all possess porous structures and exhibit excellent adsorption capabilities for various small molecule gases.

[0064] Table 1. Specific surface area and small molecule adsorption capacity of POP-CTF-XP / PCT prepared in the examples.

[0065]

[0066] Furthermore, safety tests were conducted on the batteries prepared in Examples 1-3, and the battery safety under high temperature, needle penetration, overcharge, short circuit and compression conditions was tested respectively. The results are shown in Table 2. The batteries prepared in the three examples all showed good performance in each test.

[0067] Table 2. Cell safety test results (based on GJB4477 standard) of the examples.

[0068] nominal capacity 150℃ Hot Box acupuncture 6V overcharge Short circuit extrusion Example 1 30Ah pass pass pass pass pass Example 2 30Ah pass pass pass pass pass Example 3 30Ah pass pass pass pass pass

[0069] The embodiments of the present invention have been described in detail above, but the content described is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A composite material, characterized in that: Using a mixture of terephthalonitrile and biphenylnitrile as monomers, POP-CTF was obtained by reacting with zinc chloride. After treatment with hydrochloric acid, a covalent triazine framework porous organic polymer, POP-CTF-X, was obtained. After pyrolysis, carbonization, and crushing, POP-CTF-XP was obtained. POP-CTF-XP was added to a methanol solution of hexachlorocyclotriphosphazene and aged at 40-60℃ for 12-72 hours. After filtration, it was vacuum dried and aged in an inert gas atmosphere tube furnace at 200-300℃ for 2-24 hours to obtain the POP-CTF-XP / PCT composite material.

2. A polymer lithium-ion battery, characterized in that: The positive electrode and / or negative electrode of the battery contain the POP-CTF-XP / PCT composite material as described in claim 1.

3. The polymer lithium-ion battery according to claim 2, characterized in that: The components for preparing the battery cathode material include 90%-98% cathode active material, 0.5%-5% conductive agent, 1%-3% binder, 0.5%-5% POP-CTF-XP / PCT, and 0.5%-2% PCT; the sum of the mass percentages of the above components is 100%. The raw material components for preparing the battery negative electrode include 90%-98% negative electrode active material, 0.5%-5% conductive agent, 1%-3% binder, and 0.5%-5% POP-CTF-XP / PCT and 0.5%-2% PCT; the sum of the mass percentages of the above components is 100%.

4. The polymer lithium-ion battery according to claim 2 or 3, characterized in that: The polymer electrolyte is an in-situ polymerized electrolyte; It is obtained by in-situ polymerization of polymer monomer solution. The polymer monomer solution components include 0.2%-10% comonomer I, 0.2%-10% comonomer II, 10%-40% lithium salt, 0.01%-1% initiator and 50%-88% small molecule solvent.

5. The polymer lithium-ion battery according to claim 4, characterized in that: Comonomer 1 is one or a combination of one or more of triallyl isocyanurate, dipentaerythritol triacrylate, dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate; Comonomer 2 is one or more of the following: trifluoroethyl methacrylate, perfluoroalkyl ethyl acrylate, tetrafluoropropyl methacrylate, hexafluorobutyl methacrylate, 3-methacryloyloxypropylmethyldimethoxysilane, and vinyl-tris(methylethyl ketoxime)silane.

6. The polymer lithium-ion battery according to claim 5, characterized in that: The lithium salt is one or a combination of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium hexafluorophosphate (LiPF6), lithium tetrafluoroborate (LiBF4), and lithium hexafluoroarsenate (LiAsF6); The initiator is one or both of benzoyl peroxide and azobisisobutyronitrile.

7. A method for preparing a polymer lithium-ion battery according to any one of claims 2-6, characterized in that: First, the positive electrode and negative electrode of the battery, which include POP-CTF-XP / PCT composite material, are prepared separately. They are then assembled with a separator to form a dry cell battery. After injecting a polymer monomer solution, the electrolyte is polymerized in situ to form an electrolyte. After formation, a polymer lithium-ion battery is obtained.

8. The method for preparing a polymer lithium-ion battery according to claim 7, characterized in that: The specific method is as follows: Step 1: Using a mixture of terephthalonitrile and biphenylnitrile as monomers, mix with zinc chloride and heat at 450-600 ℃ for 10-48 h to obtain POP-CTF solution. Treat with hydrochloric acid solution at 80 ℃ and deionized water at 100 ℃ to obtain POP-CTF-X. POP-CTF-X is then pyrolyzed at 700-1500 ℃, cooled, and crushed to obtain pyrolytic POP-CTF-XP. Step 2: Dissolve hexachlorocyclotriphosphazene in methanol to prepare a PCT / methanol solution with a mass fraction of 1%-20%. Add POP-CTF-XP to the PCT / methanol solution and age it fully at 40-60℃ for 12-72 hours. After filtration, dry it under vacuum at 100℃ and age it in an inert gas atmosphere tube furnace at 200-300℃ for 2-24 hours to obtain the POP-CTF-XP / PCT composite material. Step 3: Use NMP as a solvent to homogenize the positive and negative electrode slurries, and then coat them to obtain positive and negative electrode sheets; assemble the positive and negative electrode sheets into the lithium-ion battery dry cell. Step 4: Prepare a polymer monomer solution, specifically comprising 0.2%-10% comonomer one, 0.2%-10% comonomer two, 10%-40% lithium salt, 0.01%-1% initiator, and 50%-88% small molecule solvent; Step 5: Inject the polymer monomer solution into the lithium-ion battery dry cell for 6-36 hours for aging and in-situ polymerization reaction, and form at 40-90℃ and 0.3-1.3MPa to obtain the polymer lithium-ion battery.

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