Solid electrolyte material based on in-situ integrated polyarylether covalent organic framework and preparation method thereof

Abstract

The invention relates to a solid electrolyte material based on an in-situ integrated polyarylether covalent organic framework and a preparation method of the solid electrolyte material. The preparation method of the solid electrolyte material based on the in-situ integrated polyarylether covalent organic framework comprises the following steps: (1) dissolving a hydroxyl building monomer, a fluorine-containing building block and an acid-binding agent in an aprotic solvent, and carrying out nucleophilic substitution reaction to obtain polyarylether COF; dispersing the polyarylether COF in a mixed solution of concentrated sulfuric acid and glacial acetic acid for hydrolysis to obtain carboxyl-functionalized polyarylether COF; (2) mixing carboxyl-functionalized polyarylether COF, an epoxy monomer, an anhydride curing agent, a lithium salt and an organic solvent to obtain slurry; and (3) coating the slurry on the surface of a positive electrode material and / or a negative electrode material, pre-drying, and heating to carry out epoxy anhydride ring-opening polymerization reaction to obtain the solid electrolyte material. According to the technical scheme, the problems that a traditional polymer electrolyte is low in ionic conductivity, poor in interface compatibility and insufficient in high-voltage stability are solved in one step.

Description

Technical Field

[0001] This invention belongs to the field of solid electrolyte materials technology, specifically relating to a solid electrolyte material based on an in-situ integrated polyarylether covalent organic framework and its preparation method. Background Technology

[0002] Solid polymer electrolytes (SPEs) are considered ideal candidates for solid electrolyte materials due to their advantages such as good flexibility, scalable processability, low cost, and stability in air. Since 2010, the Bolloré Group has applied SPE-based solid-state polymer electrolytes (LMBs) as power sources for electric vehicles and grid energy storage (>1 GWh), providing industrial examples to support the development of high-performance solid-state LMBs.

[0003] With the continuous development of solid-state batteries, novel solid-state electrolytes (SPEs) have been extensively studied, including polyethylene glycol (PEO), polysiloxane (PS), polyethylene succinate (PE-2,4), poly(β-propiolactone) (PPL), polyethylene glycol methacrylate (PEGMA), poly(1,3-dioxolane) (PDOL), and polytetrahydrofuran (PTHF). However, their ionic conductivity is far inferior to that of liquid electrolytes. In SPEs, lithium ions are complexed and coordinated with polar groups (-O-, =O, -S-, -N-, -P-, C=O, C≡N) on the polymer chain and migrate with the movement of local polymer chain segments. Therefore, reducing the jumping energy barrier of lithium ions during polymer chain segment movement, increasing carrier concentration, and expanding ion transport pathways will effectively promote the practical application of SPEs.

[0004] Covalent organic frameworks (COFs) possess highly controllable porous structures, providing abundant open ion diffusion channels for lithium-ion transport. Their ordered pore size distribution generates a nano-confinence domain effect, preventing direct contact between the electrolyte and electrode and enabling uniform lithium deposition and stripping. Furthermore, COFs offer a wealth of tunable organic building blocks, allowing for adjustment of redox potentials, and their unique organic properties exhibit excellent polymer matrix compatibility. Therefore, the synergistically driven crosslinking network formed based on COFs, as a multifunctional polymer, can provide abundant coordination bonds for lithium salt dissociation, effectively promoting dissociation during lithium-ion migration and potentially addressing the issues of poor ionic conductivity and electrochemical stability in SPEs.

[0005] Although COFs materials have multiple advantages, there are still technical challenges in constructing high-performance solid-state batteries, such as: (1) Electrochemical stability needs to be improved: The reversible covalent bonds of COFs result in a low working voltage that the framework structure can withstand, which cannot be adapted to high-voltage cathodes to form a stable electrode interface. (2) Traditional SPEs preparation and assembly methods may lead to poor solid / solid interface compatibility and low ionic conductivity.

[0006] To address the aforementioned issues, this invention proposes a novel solid-state electrolyte material and its preparation method. The method involves preparing electrochemically stable polyarylene ether COFs as the main structural component, and then grafting high-dielectric-constant polyester chains onto the COFs via ring-opening polymerization of epoxy and acid anhydride. This regulates the electronic structure within the macropore volume of the COFs, enhancing ion conductivity within the pores. This allows for the in-situ construction of a series of SPEs (PE-COF) films with excellent ionic conductivity and surface / interface stability at the electrode interface. Summary of the Invention

[0007] The present invention aims to provide a method for preparing a solid electrolyte material based on an in-situ integrated polyarylether covalent organic framework. The method uses an electrochemically stable polyarylether COF with a three-dimensional through-pore structure (pore size 2–10 nm) as a rigid framework. In-situ ring-opening polymerization of epoxy-anhydride is initiated within the uniform pores of the COF, grafting high-dielectric polyester / polyether segments with a number-average molecular weight of 500–10000 g / mol to form a "rigid COF-flexible polyester" interpenetrating crosslinked network. Lithium salts (LiTFSI, LiFSI, LiBOB, or combinations thereof) are uniformly dispersed within the crosslinked network and form a conformal interface layer with the electrode substrate. This effectively solves the defects in existing polymer solid electrolytes, such as low ion conduction efficiency, poor interfacial compatibility, and uneven dispersion and poor interfacial contact between inorganic fillers and the polymer matrix.

[0008] To achieve the above objectives, the technical solution adopted is as follows:

[0009] The preparation method of solid electrolyte materials based on in-situ integrated polyarylether covalent organic frameworks includes the following steps:

[0010] (1) Preparation of polyarylether covalent organic framework

[0011] After dissolving hydroxyl monomers, fluorinated building blocks, and acid-binding agents in an aprotic solvent, a nucleophilic substitution reaction was carried out at 120-160 °C for 48-120 h to obtain cyano-functionalized polyarylene ether COF.

[0012] The polyarylene ether COF is then dispersed in a mixed solution of concentrated sulfuric acid and glacial acetic acid and hydrolyzed at 80-100℃ for 2-6 hours to obtain carboxyl-functionalized polyarylene ether COF.

[0013] (2) The carboxyl-functionalized polyarylene ether (COF), epoxy monomer, acid anhydride curing agent, lithium salt and organic solvent are mixed and fully dispersed to obtain a homogeneous polymer electrolyte precursor slurry;

[0014] (3) The polymer electrolyte precursor slurry is coated on the surface of the positive electrode material and / or the negative electrode material, pre-baked at 60-120℃ for 0.5-2h, and then heated to carry out the epoxy-anhydride ring-opening polymerization reaction to obtain PE-COF solid electrolyte, i.e. the solid electrolyte material.

[0015] Furthermore, in step (1), the hydroxyl monomer is at least one of hexahydroxytriptene, 2,3,9,10,16,17,23,24-octahydroxy-29H,34H-nitrophthalocyanine, and hexahydroxytriphenylene.

[0016] The fluorinated building block is tetrafluoroterephthalonitrile;

[0017] acid-binding agent is Or triethylamine;

[0018] The aprotic solvent is one of mesitylene and DMF, DMAc, NMP, and DMSO.

[0019] Furthermore, in step (2), the epoxy monomer is one of propylene oxide, bisphenol A diglycidyl ether, and 3,4-epoxycyclohexyl carbamate.

[0020] The anhydride curing agent is one of methylsuccinic anhydride, methylhexahydrophthalic anhydride, and nadic anhydride;

[0021] The lithium salt is selected from at least one of lithium bis(trifluoromethanesulfonyl)imide, lithium hexafluorophosphate, lithium bis(fluorosulfonyl)imide, lithium tetrafluoroborate, lithium nitrate, lithium difluorooxalate borate, lithium tetrafluorooxalate phosphate, or lithium perchlorate.

[0022] The organic solvent is ethylene glycol dimethyl ether, tetrahydrofuran, or carbonates.

[0023] Furthermore, in step (1), the molar ratio of the hydroxyl monomer, the fluorine-containing building block, and the acid-binding agent is 1:2:10-40; the volume ratio of concentrated sulfuric acid and glacial acetic acid in the mixed solution is 1:1-3.

[0024] In step (2), the molar ratio of epoxy monomer to anhydride curing agent is 1:0.8-1.0; the amount of carboxyl-functionalized polyarylene ether (COF) added is 10-30 wt% of the total amount of epoxy monomer and anhydride curing agent; the concentration of lithium salt is 1 mol / L; and the organic solvent is dimethyl carbonate.

[0025] Furthermore, in step (3), the temperature of the epoxy-anhydride ring-opening polymerization reaction is 80-150°C. o C, the time is 2-12 hours.

[0026] Furthermore, in step (3), the temperature of the epoxy-anhydride ring-opening polymerization reaction is 100°C. o C.

[0027] Another objective of this invention is to provide a solid electrolyte material based on an in-situ integrated polyarylether covalent organic framework, prepared by the above-described method, which can be in-situ integrated on the electrode surface and has the advantages of high room temperature ionic conductivity and wide voltage window.

[0028] Another objective of this invention is to provide a polymer solid-state battery with the advantage of high energy density.

[0029] To achieve the above objectives, the technical solution adopted is as follows:

[0030] A polymer solid-state battery comprising the aforementioned solid electrolyte material.

[0031] Furthermore, the polymer solid-state battery also includes a positive electrode material and a negative electrode material:

[0032] The cathode material is selected from at least one of lithium cobalt oxide, nickel-cobalt-manganese ternary, nickel-cobalt-aluminum, lithium iron phosphate, lithium-rich manganese-based or high-pressure nickel-manganese spinel;

[0033] The negative electrode material is a negative electrode active material, and lithium metal or lithium alloy is selected.

[0034] The solid electrolyte material is in situ integrated onto the surface of the positive electrode material and / or the negative electrode material.

[0035] Furthermore, a layer of the solid electrolyte material is disposed between the positive electrode material and the negative electrode material.

[0036] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0037] The technical solution of this invention uses electrochemically stable polyaryl ether COF as a rigid three-dimensional framework, and utilizes the carboxyl groups within its channels to catalyze the ring-opening polymerization of epoxy-anhydride, grafting high-dielectric polyester / polyether segments in situ to construct a "rigid COF-flexible polymer" interpenetrating crosslinked network; lithium salt is uniformly dispersed within the network and forms a conformal interface layer with the electrode surface. The specific advantages are:

[0038] (1) The rigid COF framework endows the material with excellent thermal stability (T d >350 ℃) and electrochemical oxidation stability.

[0039] (2) The flexible polyester segments generated by in-situ ring-opening polymerization of epoxy-anhydride have both high dielectric constant and good segment mobility, which can significantly improve the degree of lithium salt dissociation and reduce the lithium ion migration barrier. The room temperature ionic conductivity can reach S / cm (25 ℃) is 1–2 orders of magnitude higher than that of traditional PEO-based SPE.

[0040] (3) In-situ solidification technology achieves conformal contact between electrolyte and electrode with "zero gap", which is beneficial to suppress dendrite growth and has a cycle life of ≥300 cycles. Attached Figure Description

[0041] Figure 1 This is a synthetic route diagram for solid electrolytes;

[0042] Figure 2 The image shows the XRD pattern of COF in Example 1;

[0043] Figure 3 The FTIR plot of COF in Example 1;

[0044] Figure 4 This is the TGA image of COF in Example 1;

[0045] Figure 5 Impedance diagram of the solid electrolyte in Example 1;

[0046] Figure 6 The cycle stability of the solid lithium metal battery assembled from the electrolyte materials in Example 1;

[0047] Figure 7 The cycle stability of the solid-state lithium metal battery assembled from the electrolyte materials in Example 2;

[0048] Figure 8 The cycle stability of the solid-state lithium metal battery assembled from the electrolyte materials in Example 3;

[0049] Figure 9 To demonstrate the cycle stability of the solid-state lithium metal battery assembled from the electrolyte materials in Comparative Example 1.

[0050] Figure 10 The cycle stability of the solid lithium metal battery assembled from the electrolyte materials in Comparative Example 2 is shown. Detailed Implementation

[0051] To further illustrate the solid electrolyte material based on the in-situ integrated polyarylene ether covalent organic framework and its preparation method, and to achieve the intended objectives of the invention, the following, in conjunction with preferred embodiments, details the specific implementation methods, structures, features, and effects of the solid electrolyte material based on the in-situ integrated polyarylene ether covalent organic framework and its preparation method proposed in this invention. In the following description, different "embodiments" or "embodiments" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable manner.

[0052] The following will provide a more detailed description of the solid electrolyte material based on the in-situ integrated polyarylether covalent organic framework and its preparation method, with reference to specific embodiments:

[0053] This invention provides a solid electrolyte material based on an in-situ integrated polyarylene ether covalent organic framework and its preparation method. The material utilizes an electrochemically stable COF as a rigid framework, initiating epoxy-anhydride ring-opening polymerization within its uniform pores, and in-situ grafting high-dielectric polyester chains to construct a "rigid COF-flexible polyester" crosslinking network. This strategy simultaneously achieves: (1) increased electron cloud density within the pores, promoting lithium salt dissociation and increasing carrier concentration; (2) continuous 3D nanochannels lowering the ion transition energy barrier and improving ionic conductivity; and (3) in-situ interfacial film formation, eliminating particle-matrix gaps and improving interfacial stability. The resulting PE-COF solid electrolyte membrane possesses both high room temperature ionic conductivity and a wide voltage window, solving the problems of low ion conduction efficiency and poor interfacial compatibility of traditional SPE in one step. The technical solution adopted in this invention is as follows:

[0054] The preparation method of solid electrolyte materials based on in-situ integrated polyarylether covalent organic frameworks includes the following steps:

[0055] (1) Preparation of polyarylether covalent organic framework

[0056] After dissolving hydroxyl monomers, fluorinated building blocks, and acid-binding agents in an aprotic solvent, a nucleophilic substitution reaction was carried out at 120-160 °C for 48-120 h to obtain cyano-functionalized polyarylene ether COF.

[0057] The polyarylene ether COF is then dispersed in a mixed solution of concentrated sulfuric acid and glacial acetic acid and hydrolyzed at 80-100℃ for 2-6 hours to obtain carboxyl-functionalized polyarylene ether COF.

[0058] (2) The carboxyl-functionalized polyarylene ether (COF), epoxy monomer, acid anhydride curing agent, lithium salt and organic solvent are mixed and fully dispersed to obtain a homogeneous polymer electrolyte precursor slurry;

[0059] (3) The polymer electrolyte precursor slurry is coated on the surface of the positive electrode material and / or the negative electrode material, pre-baked at 60-120℃ for 0.5-2h, and then heated to carry out the epoxy-anhydride ring-opening polymerization reaction to obtain PE-COF solid electrolyte, i.e. the solid electrolyte material.

[0060] The mechanism of the present invention in the above technical solution is as follows:

[0061] A series of electrochemically stable polyarylene ether COFs were synthesized based on nucleophilic substitution reactions. These COFs exhibit excellent electrochemical stability, thermal stability, and mechanical stability under extreme conditions (such as high temperature, strong acid, strong base, and strong polar solvent). They can not only regulate lithium-ion transport behavior but also improve the oxidation potential of the material and optimize its compatibility with high-voltage cathode materials.

[0062] Then, by grafting high-dielectric-constant polyester chains onto the COF structure through ring-opening polymerization of epoxy and acid anhydride, in-situ integration of polyarylene ether covalent organic framework-based solid electrolytes (PE-COF) on the electrode substrate can be achieved. The polyester or polyurethane molecular chains generated by the ring-opening polymerization of epoxy and acid anhydride can act as connectors within the COF pores, improving ion conduction within the pores and enhancing the ionic conductivity and interfacial stability of the COFs.

[0063] Furthermore, by employing "in-situ curing" technology, polymer electrolytes can be integrated in situ onto the electrode surface, achieving ultraconformal interface compatibility and improving the compatibility of the electrode-electrolyte interface. Applying this technology to solid-state batteries provides a reliable electrolyte solution for high-energy-density solid-state batteries.

[0064] Preferably, in step (1), the hydroxyl monomer is at least one of hexahydroxytriptene, 2,3,9,10,16,17,23,24-octahydroxy-29H,34H-nitrophthalocyanine, and hexahydroxytriphenylene.

[0065] The fluorinated building block is tetrafluoroterephthalonitrile;

[0066] The acid-binding agent is K2CO3 or triethylamine;

[0067] The aprotic solvent is one of mesitylene (Mes) and DMF, DMAc, NMP, and DMSO.

[0068] In the above technical solution, after completing the nucleophilic substitution reaction, the present invention further includes post-treatment: filtration, washing the resulting black precipitate with DMA, DMF, H2O, CH2Cl2, and THF until the filtrate is colorless. Then, it is transferred to a Soxhlet extractor and washed with acetone (24 h). Finally, it is dried.

[0069] Preferably, in step (2), the epoxy monomer is one of propylene oxide, bisphenol A diglycidyl ether, and 3,4-epoxycyclohexyl carbamate.

[0070] The anhydride curing agent is one of methylsuccinic anhydride, methylhexahydrophthalic anhydride, and nadic anhydride;

[0071] The lithium salt is selected from lithium bis(trifluoromethanesulfonylimide) ( Lithium hexafluorophosphate () Lithium difluorosulfonylimide ( Lithium tetrafluoroborate () Lithium nitrate () Lithium difluorooxalate borate ( ) Lithium tetrafluorooxalate phosphate () ), or lithium perchlorate ( At least one of the following;

[0072] The organic solvent is ethylene glycol dimethyl ether, tetrahydrofuran, or carbonates.

[0073] Preferably, in step (1), the molar ratio of the hydroxyl monomer, the fluorinated building block, and the acid-binding agent is 1:2:10-40; the volume ratio of concentrated sulfuric acid and glacial acetic acid in the mixed solution is 1:1-3.

[0074] In step (2), the molar ratio of epoxy monomer to anhydride curing agent is 1:0.8-1.0; the amount of carboxyl-functionalized polyarylene ether (COF) added is 10-30 wt% of the total amount of epoxy monomer and anhydride curing agent; the concentration of lithium salt is 1 mol / L; and the organic solvent is dimethyl carbonate.

[0075] Preferably, in step (3), the temperature of the epoxy-anhydride ring-opening polymerization reaction is 80-150°C. o C, the time is 2-12 hours.

[0076] More preferably, in step (3), the temperature of the epoxy-anhydride ring-opening polymerization reaction is 100°C. o C.

[0077] A polymer solid-state battery includes the aforementioned solid electrolyte material based on a polyarylether covalent organic framework.

[0078] Preferably, the polymer solid-state battery further includes a positive electrode material and a negative electrode active material:

[0079] (a) Positive electrode: selected from at least one of lithium cobalt oxide, nickel cobalt manganese ternary, nickel cobalt aluminum, lithium iron phosphate, lithium-rich manganese-based or high-pressure nickel manganese spinel;

[0080] (b) Negative electrode: lithium metal or lithium alloy;

[0081] (c) Electrolyte: It is integrated in situ on the surface of the positive and / or negative electrodes.

[0082] Where specific techniques or conditions are not specified in the examples, they shall be performed in accordance with the techniques or conditions described in the literature in this field or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0083] Combination Figure 1 The synthetic route of this invention includes the following preparation process: (1) nucleophilic substitution synthesis of cyanopolyarylene ether COF (COF), followed by acid hydrolysis to obtain carboxyl-functionalized COOH-COF; (2) ball milling to prepare a coating slurry containing COOH-COF, epoxy monomer, anhydride curing agent, lithium salt, and solvent; (3) coating the slurry onto the electrode surface, pre-baking, and then triggering epoxy-anhydride polymerization by heating / microwave / high-energy radiation to achieve in-situ curing of the electrolyte into a film. The obtained PE-COF electrolyte has a room temperature ionic conductivity of 1.0 × 10⁻⁶. -4 –10×10 -3 S / cm (25℃), when applied to lithium metal solid-state batteries, helps alleviate lithium dendrite growth, and has a cycle life of ≥300 cycles.

[0084] Example 1.

[0085] The specific operating steps are as follows:

[0086] (1) Preparation of polyarylether covalent organic framework

[0087] 2,3,9,10,16,17,23,24-octahydroxy-29H,34H-phthalocyanine nickel (NiPc-8OH 50.0 mg, 0.07 mmol) and tetrafluoroterephthalonitrile (28.6 mg, 0.14 mmol) monomers were dissolved in a mixed solution of N,N-dimethylacetamide (DMAc, 1.5 mL) and mesitylene (1.5 mL). Then, 1.4 mmol of triethylamine (TEA) catalyst was added, and the mixture was dispersed by sonication for approximately 15 minutes and then sealed under vacuum. The reaction was heated at 120 °C for 72 h, and the mixture was filtered to obtain a black precipitate.

[0088] The precipitate was washed sequentially with DMA, DMF, H2O, CH2Cl2, and THF until the filtrate was colorless. The powder sample was then transferred to a Soxhlet extractor and washed with acetone (24 h). Finally, it was dried at 120 °C to obtain a cyano-functionalized polyarylene ether (COF) powder sample.

[0089] Disperse polyarylene COF products in concentrated... Hydrolysis was performed at 80°C for 5 h in a mixture of glacial acetic acid and acetic acid (volume ratio 1:2) to convert cyano groups to carboxyl groups. The resulting sample was filtered and refluxed in water for 2 h, followed by reflux in 1 M hydrochloric acid for 2 h. The solid was collected by vacuum filtration, washed with water, tetrahydrofuran, and ethanol solution, and then refluxed at 80°C. o Solvent was removed under vacuum at C to obtain black COOH-COF powder, which is a carboxyl-functionalized polyaryl ether COF. The -COOH functional group can serve as a catalyst for the ring-opening polymerization of epoxy-anhydride.

[0090] (2) Preparation of slurry

[0091] Propylene oxide (175 mg, 3 mmol), methyl succinic anhydride (345 mg, 3 mmol), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI, the lithium salt concentration after mixing is 1 mol / L) and dimethyl carbonate (DMC, 5 mL) were mixed, and then carboxyl-functionalized covalent organic framework (i.e., the carboxyl-functionalized polyarylene ether COF powder in step (1), which is COOH-COF, accounting for 20 wt% of the total mass of epoxy monomer and anhydride) was added. After thorough dispersion, a homogeneous polymer electrolyte precursor slurry was obtained.

[0092] (3) The polymer electrolyte precursor slurry is coated onto the positive electrode surface by a scraping method, pre-baked at 60°C for 1 h to remove the solvent, and then subjected to epoxy-anhydride ring-opening polymerization at 100°C to achieve in-situ grafting of polyester chains into the COF channels and the formation of a conformal interface with the electrode, thus obtaining PE-COF-1 solid electrolyte. Specifically: NCM811 is used as the positive electrode, and the polymer electrolyte precursor solution in step 2 is uniformly coated onto the surface of the NCM811 positive electrode. Epoxy-anhydride ring-opening polymerization is carried out at 100°C for 12 h to integrate the electrolyte in situ on the positive electrode surface. The Li sheet is used as the negative electrode, and the battery is assembled for electrochemical testing.

[0093] Example 2.

[0094] The specific operating steps are as follows:

[0095] (1) Preparation of polyarylether covalent organic framework

[0096] 2,3,9,10,16,17,23,24-octahydroxy-29H,34H-phthalocyanine nickel (NiPc-8OH 50.0 mg, 0.07 mmol) and tetrafluoroterephthalonitrile (28.6 mg, 0.14 mmol) monomers were dissolved in a mixed solution of N,N-dimethylacetamide (DMAc 1.5 mL) and mesitylene (1.5 mL). Then, 1.4 mmol of triethylamine (TEA) catalyst was added, and the mixture was dispersed by sonication for approximately 15 minutes and then sealed under vacuum. The reaction was heated at 120 °C for 72 h, and the mixture was filtered to obtain a black precipitate. The precipitate was washed with DMA, DMF, H2O, CH2Cl2, and THF until the filtrate was colorless. The powder sample was then transferred to a Soxhlet extractor and washed with acetone (24 h). Finally, the powder was dried at 120 °C to obtain a cyano-functionalized polyarylene ether (COF) powder sample.

[0097] Disperse polyarylene COF products in concentrated... Hydrolysis was performed at 80°C for 5 h in a mixture of glacial acetic acid and hydrochloric acid (volume ratio 1:2) to convert cyano groups to carboxyl groups. The resulting sample was filtered and refluxed in water for 2 h, followed by reflux in 1 M hydrochloric acid for 2 h. The solid was collected by vacuum filtration, washed with water, tetrahydrofuran, and ethanol solutions, and the solvent was removed under vacuum at 80°C to obtain a black COOH-COF powder, which is a carboxyl-functionalized polyaryl ether COF. The -COOH functional group can serve as a catalyst for the ring-opening polymerization of epoxy-anhydride.

[0098] (2) Preparation of slurry

[0099] Propylene oxide (175 mg, 3 mmol), methyl succinic anhydride (345 mg, 3 mmol), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI, the lithium salt concentration after mixing is 1 mol / L) and dimethyl carbonate (DMC, 5 mL) were mixed, and then carboxyl-functionalized covalent organic framework (i.e., the carboxyl-functionalized polyarylene ether COF powder in step (1), which is COOH-COF, accounting for 10 wt% of the total mass of epoxy monomer and anhydride) was added. After thorough dispersion, a homogeneous polymer electrolyte precursor slurry was obtained.

[0100] (3) The polymer electrolyte precursor slurry is coated onto the positive electrode surface by a scraping method, pre-baked at 60 °C for 1 h to remove the solvent, and then subjected to epoxy-anhydride ring-opening polymerization at 100 °C to achieve in-situ grafting of polyester chains into the COF channels and form a conformal interface with the electrode, thus obtaining PE-COF-2 solid electrolyte. Specifically: NCM811 is used as the positive electrode, and the polymer electrolyte precursor solution in step 2 is uniformly coated onto the surface of the NCM811 positive electrode. Epoxy-anhydride ring-opening polymerization is carried out at 100 °C for 12 h to integrate the electrolyte in situ on the positive electrode surface. The Li sheet is used as the negative electrode, and the battery is assembled for electrochemical testing.

[0101] Example 3.

[0102] The specific operating steps are as follows:

[0103] (1) Preparation of polyarylether covalent organic framework

[0104] 2,3,9,10,16,17,23,24-octahydroxy-29H,34H-phthalocyanine nickel (NiPc-8OH 50.0 mg, 0.07 mmol) and tetrafluoroterephthalonitrile (28.6 mg, 0.14 mmol) monomers were dissolved in a mixed solution of N,N-dimethylacetamide (DMAc 1.5 mL) and mesitylene (1.5 mL). Then, 1.4 mmol of triethylamine (TEA) catalyst was added, and the mixture was dispersed by sonication for approximately 15 minutes and then sealed under vacuum. The reaction was heated at 120 °C for 72 h, and the mixture was filtered to obtain a black precipitate. The precipitate was washed with DMA, DMF, H2O, CH2Cl2, and THF until the filtrate was colorless. The powder sample was then transferred to a Soxhlet extractor and washed with acetone (24 h). Finally, the powder was dried at 120 °C to obtain a cyano-functionalized polyarylene ether (COF) powder sample.

[0105] Disperse polyarylene COF products in concentrated... Hydrolysis was performed at 80°C for 5 h in a mixture of glacial acetic acid and sodium chloride (volume ratio 1:2) to convert cyano groups to carboxyl groups. The resulting sample was filtered and refluxed in water for 2 h, followed by reflux in 1 M hydrochloric acid for 2 h. The solid was collected by vacuum filtration, washed with water, tetrahydrofuran, and ethanol solutions, and the solvent was removed under vacuum at 80°C to obtain a black COOH-COF powder, which is a carboxyl-functionalized polyaryl ether COF. The -COOH functional group can serve as a catalyst for the ring-opening polymerization of epoxy-anhydride.

[0106] (2) Preparation of slurry

[0107] Propylene oxide (175 mg, 3 mmol), methyl succinic anhydride (345 mg, 3 mmol), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI, the lithium salt concentration after mixing is 1 mol / L) and dimethyl carbonate (DMC, 5 mL) were mixed, and then carboxyl-functionalized covalent organic framework (i.e., the carboxyl-functionalized polyarylene ether COF powder in step (1), which is COOH-COF, accounting for 30 wt% of the total mass of epoxy monomer and anhydride) was added. After thorough dispersion, a homogeneous polymer electrolyte precursor slurry was obtained.

[0108] (3) The polymer electrolyte precursor slurry is coated onto the positive electrode surface by a scraping method, pre-baked at 60°C for 1 hour to remove the solvent, and then subjected to epoxy-anhydride ring-opening polymerization at 100°C to achieve in-situ grafting of polyester chains into the COF channels and the formation of a conformal interface with the electrode, thus obtaining PE-COF-3 solid electrolyte. Specifically: NCM811 is used as the positive electrode, and the polymer electrolyte precursor solution in step 2 is uniformly coated onto the surface of the NCM811 positive electrode. Epoxy-anhydride ring-opening polymerization is carried out at 100°C for 12 hours to integrate the electrolyte in situ on the positive electrode surface. The Li sheet is used as the negative electrode, and the battery is assembled for electrochemical testing.

[0109] Example 4.

[0110] The operation steps of Example 4 are the same as those of Example 1, except for the selection of the hydroxyl monomer and the acid-binding agent. See Table 1 for details.

[0111] Table 1

[0112]

[0113] Example 5.

[0114] The operating steps of Example 5 are the same as those of Example 1, except for the choice of aprotic solvent and the volume ratio of concentrated sulfuric acid to glacial acetic acid. See Table 2 for details.

[0115] Table 2

[0116]

[0117] Example 6.

[0118] The operating steps of Example 6 are the same as those of Example 1, except for the molar amount of the acid-binding agent. See Table 3 for details.

[0119] Table 3

[0120]

[0121] Example 7.

[0122] The operating steps of Example 7 are the same as those of Example 1, except for the selection of lithium salt and organic solvent. See Table 4 for details.

[0123] Table 4

[0124]

[0125] Example 8.

[0126] The operating steps of Example 8 are the same as those of Example 1, except for the selection and molar amounts of the epoxy monomer and the acid anhydride curing agent. See Table 5 for details.

[0127] Table 5

[0128]

[0129] Example 9.

[0130] The operating steps of Example 9 are the same as those of Example 1, except for the conditions of the epoxy-anhydride ring-opening polymerization reaction. See Table 6 for details.

[0131] Table 6

[0132]

[0133] Comparative Example 1.

[0134] This comparative example provides an in-situ integrated polyarylene ether covalent organic framework-based solid electrolyte material. The preparation method is basically the same as that in Example 1, except that step (1) is not performed, that is, the preparation of the slurry in step (2) is carried out directly, that is, COOH-COF is not added to the slurry.

[0135] Comparative Example 2.

[0136] This comparative example provides an in-situ integrated polyarylene ether covalent organic framework-based solid electrolyte material. The preparation method is basically the same as that in Example 1, except that the polyarylene ether covalent organic framework powder (i.e., carboxyl-functionalized polyarylene ether COF) obtained in step 1 is directly used as a filler for the polymer electrolyte and then physically mixed in step 2 to prepare a solid battery.

[0137] The operation steps of Comparative Example 2 are the same as those of Example 1, except that: the polymer electrolyte precursor slurry obtained in step 2 is coated on the surface of the positive electrode, and after pre-baking at 60 °C for 1 h to remove the solvent, the epoxy-anhydride ring-opening polymerization reaction is not performed, and the solid electrolyte is obtained directly.

[0138] Example 10: Performance Testing

[0139] 1. Physical and chemical properties

[0140] The physicochemical properties of the polyarylene ether-based two-dimensional covalent organic frameworks (COFs, i.e., the cyano-functionalized polyarylene ether COF powder sample in Example 1) in Example 1 were tested, specifically:

[0141] Figure 2 The image shows the XRD pattern of the COF in Example 1. The crystal structure of the polyarylene ether-based two-dimensional covalent organic framework (COFs) was systematically analyzed using powder X-ray diffraction (PXRD) combined with theoretical structural simulation. The experimental PXRD pattern exhibits typical crystallization diffraction characteristics, with obvious diffraction peaks observed at 2θ = 4.5° and 27.1°, attributed to Bragg reflections of the (100) and (001) crystal planes, respectively, indicating that the material has a layered tetragonal lattice stacked structure. The theoretically simulated diffraction pattern based on the overlapping AA stacking model is in high agreement with the experimental data, confirming the crystal structure model of the prepared COFs.

[0142] Figure 3 The image shows the FTIR spectrum of the COF in Example 1; Fourier transform infrared spectroscopy (FT-IR) analysis shows that the COF material has a specific wavelength of 1273 nm. and 1007 Characteristic absorption peaks appear at these locations, which are attributed to the asymmetric stretching vibrations of the C–O bonds in the dioxin ring. ) and symmetrical stretching vibration ( The above spectral characteristics clearly confirm aromatic nucleophilic substitution (S). N The successful conduct of the Ar) reaction and the efficient construction of a polyarylene ether-based two-dimensional covalent organic framework containing dioxin linkages.

[0143] Figure 4 The TGA image shows the COF from Example 1. Thermogravimetric analysis (TGA) results indicate that this COF material exhibits excellent thermal stability with no significant mass loss observed below 400 °C. This high thermal stability can be attributed to the high bond energy of the dioxin linkages and the rigid structure of the aromatic skeleton, which effectively suppresses thermal decomposition reactions.

[0144] 2. Electrical performance

[0145] All-solid-state batteries assembled from the polymer electrolytes prepared in Examples 1-3 and Comparative Examples 1-2 were subjected to electrochemical tests.

[0146] Test method:

[0147] Using 5 mg of active NCM811 as the positive electrode, the prepared polymer electrolyte precursor solution was uniformly coated onto the positive electrode surface. The reaction was carried out at 100℃ for 12 h to integrate the electrolyte in situ on the positive electrode surface. A Li sheet was used as the negative electrode, and the battery was assembled. Its charge-discharge performance and cycle stability were tested. Charge-discharge test conditions: 1 C.

[0148] Test results are available Figure 5-10 Specifically:

[0149] Figure 5 The impedance diagram is shown for the solid electrolyte in Example 1. Electrochemical impedance spectroscopy (EIS) tests show that the PE-COF-1 electrolyte exhibits excellent ion conduction characteristics over a wide temperature range of 30–60 °C. Specifically, the ion conductivity at 30 °C reaches 3.4 mS / cm, significantly better than that of traditional polyether-based solid electrolyte systems.

[0150] Figure 6 The cycle stability of the solid lithium metal battery assembled from the electrolyte materials in Example 1; Figure 6 This study presents the long-term cycling performance of the Li|PE-COF-1|NCM811 full cell at 1C rate. After the first 3 activation cycles, the discharge specific capacity of the battery system stabilizes at approximately 138 mAh / g; after 300 cycles, the capacity retention is as high as approximately 95% (>130 mAh / g), demonstrating excellent long-term cycling stability. Figure 6 b shows the voltage-specific capacity curves of the battery during the first three cycles. The first charge-discharge curve shows a typical sloping voltage plateau, corresponding to the in-situ formation process of the electrode / electrolyte interface. The curves of the second and third cycles highly overlap, and the polarization voltage decreases significantly, indicating that the solid electrolyte interface (SEI) layer has been stably constructed and the battery has entered a stable electrochemical cycling state.

[0151] Figure 7 The cycle stability of the solid-state lithium metal battery assembled from the electrolyte materials in Example 2; Figure 7 This paper presents the long-term cycling performance evolution of the Li|PE-COF-2|NCM811 full cell at 1C rate. After the first 3 activation cycles, the discharge specific capacity of the battery system stabilizes at approximately 140 mAh / g; however, after 200 cycles, the capacity decays to approximately 100 mAh / g, with a capacity retention of only 71%, showing a clear capacity degradation trend. Figure 7 b is the voltage-specific capacity curve of the battery during the first 3 cycles. The first charge-discharge curve shows a typical sloping voltage plateau, which corresponds to the in-situ formation process of the electrode / electrolyte interface.

[0152] Figure 8 The cycle stability of the solid-state lithium metal battery assembled from the electrolyte materials in Example 3; Figure 8 This paper presents the long-term cycling performance evolution of the Li|PE-COF-3|NCM811 full cell at 1C rate. After the first 3 activation cycles, the discharge specific capacity of the battery system stabilizes at approximately 118 mAh / g; however, after 200 cycles, the capacity decays to approximately 80 mAh / g, with a capacity retention of only 68%, showing a clear capacity degradation trend. Figure 8 b is the voltage-specific capacity curve of the battery during the first 3 cycles. The first charge-discharge curve shows a typical sloping voltage plateau, which corresponds to the in-situ formation process of the electrode / electrolyte interface.

[0153] Figure 9 To demonstrate the cycle stability of the solid-state lithium metal battery assembled from the electrolyte materials in Comparative Example 1. Figure 9 a presents the long-term cycling performance evolution of the full cell constructed using the electrolyte prepared in Comparative Example 1 at a 1C rate. After the first 3 activation cycles, the discharge specific capacity of this battery system stabilizes at approximately 100 mAh / g; however, after 200 cycles, the capacity decays to approximately 30 mAh / g, with a capacity retention of only 30%, exhibiting a significant capacity degradation trend. Figure 9 b is the voltage-specific capacity curve of the battery during the first 3 cycles. The first charge-discharge curve shows a typical sloping voltage plateau, which corresponds to the in-situ formation process of the electrode / electrolyte interface.

[0154] Figure 10 The cycle stability of the solid lithium metal battery assembled from the electrolyte materials in Comparative Example 2 is shown. Figure 10 The evolution of the long-term cycling performance of the full cell constructed using the electrolyte prepared in Comparative Example 2 at 1C rate is presented. After the first 3 activation cycles, the discharge specific capacity of this battery system stabilizes at approximately 140 mAh / g; however, after 190 cycles, the capacity decays to approximately 90 mAh / g, with a capacity retention of only 64%, exhibiting a significant capacity degradation trend.

[0155] The results showed that Example 1 (PE-COF-1, Figure 6 The discharge specific capacity remained stable at 138 mAh / g; after 300 cycles, the capacity retention was as high as 95% (>130 mAh / g), demonstrating excellent long-term cycling stability. Voltage-specific capacity curve ( Figure 6 b) shows that the first-round tilted voltage plateau corresponds to the in-situ formation of the electrode / electrolyte interface, and the second and third round curves highly overlap and the polarization voltage decreases significantly, indicating that the solid electrolyte interface (SEI) layer has been stably constructed.

[0156] Examples 2-3 (PE-COF-2 / 3, Figure 7-8 The initial capacities were 140 mAh / g and 118 mAh / g, respectively, but the cycling stability deteriorated significantly. After 200 cycles, PE-COF-2 retained only 71% of its capacity. Figure 7 ), while PE-COF-3 is 68% ( Figure 8 Both curves show interface formation characteristics in the first cycle, but the polarization voltage continues to increase in subsequent cycles, suggesting that the SEI layer is not stable enough and cannot effectively suppress interface side reactions and impedance accumulation in long-term cycling.

[0157] Comparative Examples 1-2 Figure 9-10 The capacity decay was more significant. Comparative Example 1 had an initial capacity of only 100 mAh / g, and after 200 cycles, the retention rate plummeted to 30%. Figure 9 Comparative Example 2 had an initial capacity of 140 mAh / g and a retention rate of 64% after 190 cycles. Figure 10 Both exhibited a severe capacity degradation trend, indicating that the COF framework structure and interfacial chemistry have a decisive influence on battery performance.

[0158] The electrolyte materials prepared in Examples 1-3 of this invention, when applied to solid-state batteries, can significantly improve the ionic conductivity of polymer electrolytes, improve poor interfacial compatibility, and address insufficient high-voltage stability.

[0159] As can be seen from the embodiments, the technical solution of the present invention uses an electrochemically stable polyarylene ether COF with a three-dimensional through-pore structure (pore size 1.4 nm) as a rigid framework; in situ, epoxy-anhydride ring-opening polymerization is initiated in the uniform pores of the COF to graft high dielectric polyester / polyether segments, forming a "rigid COF-flexible polyester" interpenetrating crosslinking network; lithium salts (LiTFSI, LiFSI, LiBOB or combinations thereof) are uniformly dispersed in the crosslinking network, and a conformal interface layer is formed with the electrode substrate.

[0160] The synergistic effect produced by this electrolyte—the combination of "rigid COF channels + carboxyl-catalyzed in-situ epoxy-anhydride ring opening"—results in a 1+1>2 effect.

[0161] Nanoscale confinement catalysis effect: The through-holes of carboxylated polyarylene ether (COF) "lock" the epoxy monomer / anhydride at the nanoscale. The confined space reduces the ring-opening activation energy, resulting in curing at 100 °C for 2 h.

[0162] The synergistic effect lies in the "dual continuity" network of oriented ion channels and flexible segments: the rigid COF framework provides 3D ordered π-conjugated channels; the in-situ grown polyester / polyether segments interpenetrate to form a "hard-soft" dual continuity phase, which is beneficial for lithium-ion migration.

[0163] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing solid electrolyte materials based on in-situ integrated polyarylether covalent organic frameworks, characterized in that, Includes the following steps: (1) Preparation of polyarylether covalent organic framework After dissolving hydroxyl monomers, fluorinated building blocks, and acid-binding agents in an aprotic solvent, a nucleophilic substitution reaction was carried out at 120-160 °C for 48-120 h to obtain cyano-functionalized polyarylene ether COF. The polyarylene ether COF is then dispersed in a mixed solution of concentrated sulfuric acid and glacial acetic acid and hydrolyzed at 80-100℃ for 2-6 hours to obtain carboxyl-functionalized polyarylene ether COF. (2) The carboxyl-functionalized polyarylene ether (COF), epoxy monomer, acid anhydride curing agent, lithium salt and organic solvent are mixed and fully dispersed to obtain a homogeneous polymer electrolyte precursor slurry; (3) The polymer electrolyte precursor slurry is coated on the surface of the positive electrode material and / or the negative electrode material, pre-baked at 60-120℃ for 0.5-2h, and then heated to carry out the epoxy-anhydride ring-opening polymerization reaction to obtain PE-COF solid electrolyte, i.e. the solid electrolyte material.

2. The preparation method according to claim 1, characterized in that, In step (1), the hydroxyl monomer is at least one of hexahydroxytriptene, 2,3,9,10,16,17,23,24-octahydroxy-29H,34H-nitrophthalocyanine, and hexahydroxytriphenylene. The fluorinated building block is tetrafluoroterephthalonitrile; The acid-binding agent is K2CO3 or triethylamine; The aprotic solvent is one of mesitylene and DMF, DMAc, NMP, and DMSO.

3. The preparation method according to claim 1, characterized in that, In step (2), the epoxy monomer is one of propylene oxide, bisphenol A diglycidyl ether, and 3,4-epoxycyclohexyl carboxylate. The anhydride curing agent is one of methylsuccinic anhydride, methylhexahydrophthalic anhydride, and nadic anhydride; The lithium salt is selected from at least one of lithium bis(trifluoromethanesulfonyl)imide, lithium hexafluorophosphate, lithium bis(fluorosulfonyl)imide, lithium tetrafluoroborate, lithium nitrate, lithium difluorooxalate borate, lithium tetrafluorooxalate phosphate, or lithium perchlorate. The organic solvent is ethylene glycol dimethyl ether, tetrahydrofuran, or carbonates.

4. The preparation method according to claim 1, characterized in that, In step (1), the molar ratio of hydroxyl monomer, fluorine-containing building block, and acid-binding agent is 1:2:10-40; the volume ratio of concentrated sulfuric acid and glacial acetic acid in the mixed solution is 1:1-3. In step (2), the molar ratio of epoxy monomer to anhydride curing agent is 1:0.8-1.0; the amount of carboxyl-functionalized polyarylene ether (COF) added is 10-30 wt% of the total amount of epoxy monomer and anhydride curing agent; the concentration of lithium salt is 1 mol / L; and the organic solvent is dimethyl carbonate.

5. The preparation method according to claim 1, characterized in that, In step (3), the temperature of the epoxy-anhydride ring-opening polymerization reaction is 80-150°C. o C, the time is 2-12 hours.

6. The preparation method according to claim 5, characterized in that, In step (3), the temperature of the epoxy-anhydride ring-opening polymerization reaction is 100°C. o C.

7. A solid electrolyte material based on an in-situ integrated polyarylether covalent organic framework, characterized in that, It is prepared by any one of the preparation methods described in claims 1-6.

8. A polymer solid-state battery, characterized in that, It includes the solid electrolyte material as described in claim 7.

9. The polymer solid-state battery according to claim 8, characterized in that, The polymer solid-state battery also includes a positive electrode material and a negative electrode material: The cathode material is selected from at least one of lithium cobalt oxide, nickel-cobalt-manganese ternary, nickel-cobalt-aluminum, lithium iron phosphate, lithium-rich manganese-based or high-pressure nickel-manganese spinel; The negative electrode material is a negative electrode active material, and lithium metal or lithium alloy is selected. The solid electrolyte material is in situ integrated onto the surface of the positive electrode material and / or the negative electrode material.

10. The polymer solid-state battery according to claim 9, characterized in that, A layer of the solid electrolyte material is disposed between the positive electrode material and the negative electrode material.

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