Preparation method of solid sodium metal battery assembled based on in-situ crystalline framework composite paper-based cellulose solid gel electrolyte

Abstract

The invention relates to a preparation method of a solid sodium metal battery assembled based on an in-situ crystalline framework composite paper-based cellulose solid gel electrolyte. Through an in-situ rotary spraying method, an AHF-SO4-2 crystalline frame material rich in SO4 < 2-> grows on a paper-based fiber diaphragm which is low in price and controllable in scale in situ, sodium salt is mixed with small molecules DOL capable of being subjected to in-situ polymerization and an ether solvent to prepare a polymer electrolyte precursor solution, and then in-situ thermal polymerization is carried out through heating in the battery, so that the polymer electrolyte is obtained. And finally obtaining the solid sodium metal battery assembled by adopting the in-situ crystalline framework composite paper-based cellulose solid gel electrolyte. According to the battery prepared by the method, the cycle life and the safety performance of the battery are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of sodium solid electrolyte materials technology, and specifically to a method for preparing a solid sodium metal battery based on an in-situ crystalline framework composite paper-based cellulose solid gel electrolyte assembly. Background Technology

[0002] Solid electrolytes have become a core new indicator for measuring the advancement of battery technology. Their performance directly determines the energy density, safety, and industrialization potential of batteries, and is currently the focus of research and competition in the battery field.

[0003] Insufficient contact between the solid electrolyte and the electrode leads to significant interfacial impedance, hindering the rapid transport of lithium ions and electrons. In-situ gel polymer electrolytes (GPEs) offer a compromise for addressing this interfacial issue. They allow for the in-situ solidification of the electrolyte precursor solution into GPEs within the battery, utilizing the wettability of the liquid to ensure good interfacial contact between the solid electrolyte and the electrode. This results in rapid chain segment movement, rapid dissociation of lithium and sodium salts, a low glass transition temperature, and good electrochemical / thermal stability. However, a simple and effective method to suppress lithium dendrite growth remains lacking for the in-situ polymerization of GPEs.

[0004] Patent No. 201811625539.0 discloses an interface modification method for a solid-state lithium battery lithium metal anode. This method employs an in-situ gel polymer generation technique to form a modification layer on the lithium metal surface. The precursor of this gel polymer contains a 1,3-dioxolane solvent (DOL) capable of in-situ ring-opening polymerization under the action of a specific lithium salt, as well as various additives that can form a stable SEI film on the lithium metal surface. The precursor can undergo in-situ polymerization on the lithium metal electrode surface through simple heating to form a viscoelastic DOL oligomer-modified buffer layer. While the gel polymer electrolyte is prepared using lithium hexafluoroarsenate (LiAsF6) as a catalyst, its high toxicity poses a risk to safe production.

[0005] Patent No. 202210493810.X discloses a gel electrolyte, its preparation method, and its application. It involves dissolving lithium bis(trifluoromethanesulfonyl)imide as the electrolyte salt in a mixed solvent prepared from 1,3-dioxolane and ethylene glycol dimethyl ether, and adding an initiator to mix thoroughly to obtain a viscous electrolyte precursor. This precursor is then polymerized to gradually form a gel electrolyte. The initiator induces the ring-opening reaction of 1,3-dioxolane, and the ethylene glycol dimethyl ether facilitates the polymerization reaction after the ring-opening reaction. However, this method suffers from insufficient mechanical strength and is susceptible to puncture.

[0006] Patent No. 201811625539.0 discloses a method for forming a gel polymer electrolyte film by in-situ heating of impregnated lithium metal sheets, which improves the interfacial physical contact between the lithium metal electrode and the solid electrolyte. However, during repeated impregnation and heating, the lithium foil negative electrode may undergo surface oxidation or lithium dendrite germination, posing a safety hazard in subsequent battery cycling. Summary of the Invention

[0007] In view of this, in order to solve the instability of interfacial contact in the non-in-situ polymerization of traditional polymer electrolytes, this invention proposes a method for preparing a solid sodium metal battery based on an in-situ crystalline framework composite paper-based cellulose solid gel electrolyte assembly.

[0008] To solve the above problems, the technical solution adopted in this invention is as follows: The preparation method of the solid sodium metal battery based on the in-situ crystalline framework composite paper-based cellulose solid gel electrolyte assembly is as follows: SO4-rich... 2- The AHF-SO4-2 crystalline framework material was grown in situ on a paper-based fiber separator. A polymer electrolyte precursor solution was prepared by mixing sodium salt with DOL, a small molecule that can be polymerized in situ, and ether solvents. The solution was then heated in situ inside the battery to achieve in-situ thermal polymerization, ultimately resulting in a solid sodium metal battery assembled using an in-situ crystalline framework composite paper-based cellulose solid gel electrolyte.

[0009] The specific method is as follows:

[0010] Step 1: Dissolve zinc sulfate heptahydrate in N,N-dimethylformamide (DMF) and ethanol, add tetramethylammonium bromide in an equimolar amount of zinc sulfate heptahydrate, and disperse it by ultrasound to prepare a colorless and transparent solution A with a concentration of 0.1-0.125 mol / L;

[0011] Weigh out 5-methyltetrazole and dissolve it in N,N-dimethylformamide (DMF) and ethanol. Add tetramethylammonium bromide in an equimolar amount of 5-methyltetrazole and disperse it by ultrasound to prepare a colorless and clear solution B with a concentration of 0.1-0.125 mol / L.

[0012] Step 2: Place the paper-based cellulose membrane on a heating plate, and use a spray gun to evenly spray solution A onto the paper-based cellulose membrane. After standing and stabilizing, wash with ethanol. Then use a spray gun to evenly spray solution B onto it. After standing and stabilizing, wash with ethanol to obtain composite membrane C.

[0013] Step 3: At room temperature, the composite membrane C is immersed in ethanol, then removed and dried in an oven to obtain the in-situ grown sulfate-enriched nitrile hybrid crystalline framework paper-based cellulose composite membrane D.

[0014] Step 4: Preparation of prepolymer precursor solution: Dissolve sodium salt in a mixed solvent of ethylene carbonate EC and dimethyl carbonate DMC, then add fluoroethylene carbonate, and stir thoroughly for 30 minutes at room temperature under inert gas protection to obtain prepolymer precursor solution E;

[0015] Step 5: Add 1,3-dioxolane (DOL) to the prepolymer precursor solution E obtained in Step 4, and then add the initiator azobisisobutyronitrile (AIBN) to obtain precursor solution F;

[0016] Step 6: In a glove box where the water and oxygen levels are both less than 0.01 ppm, the precursor solution E is dropped into the prepared sulfate-enriched nitrogen-azole hybrid crystalline framework paper-based cellulose composite membrane D. The battery is assembled with sodium vanadium phosphate as the positive electrode and metallic sodium as the negative electrode. The battery is placed in an oven for in-situ thermal polymerization, and finally a solid sodium metal battery assembled with an in-situ crystalline framework composite paper-based cellulose solid gel electrolyte is obtained.

[0017] Furthermore, the ultrasound time in step 1 is 5-10 minutes.

[0018] Furthermore, in step 2, the temperature of the heating plate is 90-110℃, and the distance between the spray gun and the glass fiber is 10 cm.

[0019] Further, in step 4, the sodium salt in the electrolyte is sodium tetrafluoroborate, and ethylene carbonate EC and dimethyl carbonate DMC with a volume ratio of 1:1 are added as a mixed solvent; then 5% by volume of fluoroethylene carbonate is added to the mixed solvent, and the mixture is stirred thoroughly for 30 minutes to obtain a prepolymer precursor solution E with a sodium salt concentration of 1 mole.

[0020] Furthermore, in step 3, the composite diaphragm C is immersed in ethanol for 12-24 hours.

[0021] Furthermore, in step 3, the oven drying temperature is 90-120℃.

[0022] Furthermore, in step 5, the amount of 1,3-dioxolane (DOL) added is 1% of the volume of the prepolymer precursor solution E, and the amount of initiator is 0.02% to 0.1% of 1,3-dioxolane (DOL).

[0023] Furthermore, in step 6, the battery is placed in an oven at 65-75℃ for in-situ thermal polymerization for 10-12 hours.

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

[0025] 1. This invention first utilizes a layer-by-layer spin-spray in-situ growth method to uniformly spin-spray a solution onto a low-cost, acid- and alkali-resistant paper substrate, allowing a crystalline two-dimensional framework rich in polynitrogen and sulfuric acid to grow uniformly and densely on the entire structure of the substrate, thus achieving controllable preparation of the separator thickness; then, an in-situ thermal polymerization method is used to uniformly encapsulate the sulfate-enriched hybrid nitrogen azole crystalline framework-based paper-based cellulose composite separator with the precursor solution, resulting in a solid-state sodium metal battery with a simple preparation method that can achieve large-scale industrial production.

[0026] 2. The sulfate-rich hybrid azole crystalline framework AHF-SO4-2 of the present invention is a highly stable two-dimensional layered crystalline framework, wherein SO4 2 Located in the symmetrical structure of each layer, it constructs directional and stable ion channels for cation transport, while efficiently immobilizing anions and enhancing free Na+. + Migration efficiency; the framework has an abundant nitrogen coordination environment, which can provide a high density of active sites, thereby effectively improving battery performance.

[0027] 3. This invention grows a crystalline framework material enriched with sulfate ions by in-situ spraying, and then combines it with paper-based cellulose through hydrogen bonding to construct a continuous ion transport channel. Combined with the dense hydrogen bond network formed by in-situ thermal polymerization of small molecules, the ionic conductivity is improved.

[0028] 4. This invention drips the precursor solution into the composite separator to achieve full wetting of the positive and negative electrode materials. While improving the battery's electrical performance through a static framework, it further enhances battery safety and meets the requirements for large-scale manufacturing of large-size batteries. Using a composite paper-based cellulose separator as a substrate, the precursor solution promotes the in-situ polymerization of 1,3-dioxolane to form a 3D cross-linked network that coats the separator, constructing a gel composite electrolyte. This effectively reduces the interfacial resistance between the electrolyte and the electrodes, ultimately significantly improving the battery's cycle life and safety.

[0029] 5. This invention utilizes the electrostatic interaction of sulfate ions with cations and the strong hydrogen bond network within the crystalline framework to assist in the in-situ growth method for uniform and dense growth and in-situ polymerization, thereby enhancing the internal chemical forces and mechanical strength of the polymer electrolyte to better match high-voltage cathode materials, thereby increasing the energy density and cycle life of the composite electrolyte.

[0030] 6. The in-situ crystalline framework composite paper-based cellulose solid gel electrolyte prepared by this invention has a charge / discharge capacity of 106 mAh g⁻¹ at a fast-charging current density of 1C. -1 The coulomb efficiency is 99%, and the capacity retention rate is 90.5% after 600 cycles. Attached Figure Description

[0031] Figure 1 This is a flowchart of the preparation process of the present invention;

[0032] Figure 2 This is a schematic diagram of the crystalline framework of Example 1 of the present invention, wherein a is a morphological image of AHF-SO4-2 synthesized in Example 1 under an electron microscope; b is a schematic diagram of the chemical structure of AHF-SO4-2 synthesized in Example 1.

[0033] Figure 3 These are the XRD and infrared spectra of the crystal synthesized in Example 1 of this invention, wherein a is the diffraction peak matching diagram of the AHF-SO4-2 crystal synthesized in Example 1 and the standard card; b is the infrared spectrum of the AHF-SO4-2 crystal synthesized in Example 1.

[0034] Figure 4 This is a thermogravimetric analysis test diagram of the crystal synthesized in Example 1 of the present invention;

[0035] Figure 5 This is a schematic diagram of the composite membrane prepared in Example 1 of the present invention, wherein a is a morphology image of the sulfate-enriched nitrogen-azole hybrid crystalline framework-based paper-based cellulose composite membrane in situ grown in Example 1 under an electron microscope; b is a magnified image of the sulfate-enriched nitrogen-azole hybrid crystalline framework-based paper-based cellulose composite membrane in situ grown in Example 1 under a scanning electron microscope.

[0036] Figure 6 This is an electrochemical window diagram of the sodium-ion battery assembled in Example 1 of the present invention;

[0037] Figure 7 This is a cycle rate diagram of the sodium-ion battery assembled in Embodiment 1 of the present invention under different current densities;

[0038] Figure 8 This is a long-cycle current diagram of the sodium-ion battery assembled in Embodiment 1 of the present invention under 1C conditions. Specific implementation methods

[0039] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It should be understood that the following embodiments are only used to explain the present invention and are not intended to limit the present invention.

[0040] This invention relates to a method for preparing a solid-state sodium metal battery based on an in-situ crystalline framework composite paper-based cellulose solid gel electrolyte assembly. The method involves in-situ spin-coating to deposit SO4-rich electrolyte. 2- The AHF-SO4-2 crystalline framework material was grown in situ on a low-cost and scalable paper-based fiber membrane. A polymer electrolyte precursor solution was prepared by mixing sodium salt with DOL, a small molecule that can be polymerized in situ, and ether solvents. The solution was then heated in situ inside the battery to achieve in-situ thermal polymerization, ultimately resulting in a solid sodium metal battery assembled using an in-situ crystalline framework composite paper-based cellulose solid gel electrolyte.

[0041] Example 1: A method for preparing a solid-state sodium metal battery based on an in-situ crystalline framework composite paper-based cellulose solid gel electrolyte assembly, as follows: Figure 1 As shown, the specific steps are as follows:

[0042] The large-area preparation method of in-situ crystalline framework composite paper-based cellulose solid gel electrolyte is as follows:

[0043] Step 1: Dissolve zinc sulfate heptahydrate in N,N-dimethylformamide (DMF) and ethanol, add tetramethylammonium bromide in an equimolar amount of zinc sulfate heptahydrate, and disperse it by sonication for 10 minutes to prepare a colorless and transparent solution A with a concentration of 0.125 mol / L;

[0044] Weigh out 5-methyltetrazole and dissolve it in N,N-dimethylformamide (DMF) and ethanol. Add tetramethylammonium bromide in an equimolar amount of 5-methyltetrazole and disperse it by sonication for 10 minutes to prepare a colorless and clear solution B with a concentration of 0.125 mol / L.

[0045] Step 2: Place a 4cm×4cm paper-based cellulose membrane on a 100℃ heating plate. The distance between the spray gun and the glass fiber is 10cm. Spray 10ml of solution A evenly with the spray gun. After standing for 20s, wash with ethanol. Then spray 10ml of solution B evenly with the spray gun. After standing for 20s, wash with ethanol. By spraying the membrane in situ layer by layer for 10 cycles, composite membrane C is obtained.

[0046] Step 3: At room temperature, the composite membrane C was immersed in ethanol for 12 hours, then removed and dried in a 100℃ oven to obtain the in-situ grown sulfate-enriched nitrile hybrid crystalline framework paper-based cellulose composite membrane D.

[0047] Step 4: Prepare the polymerization precursor solution in a glove box where the water and oxygen values ​​are both less than 0.01 ppm: Dissolve sodium tetrafluoroborate (NaBF4) in a mixed solvent of ethylene carbonate EC and dimethyl carbonate DMC with a volume ratio of 1:1, then add 5% fluoroethylene carbonate to the mixed solvent, and stir thoroughly for 30 minutes at room temperature under argon protection to obtain a prepolymerization precursor solution E with a sodium salt content of 1 mole;

[0048] Step 5: Add 1% by volume of 1,3-dioxolane (DOL) to the prepolymer precursor solution E obtained in Step 4, and then add the initiator azobisisobutyronitrile (AIBN) at a rate of 0.02% of the mass of DOL to obtain precursor solution F.

[0049] Step 6: In a glove box where the water and oxygen levels are both less than 0.01 ppm, 100 μL of precursor solution F is dropped into the prepared sulfate-enriched nitrile hybrid crystalline framework paper-based cellulose composite membrane D. The battery is assembled with sodium vanadium phosphate as the positive electrode and metallic sodium as the negative electrode. The assembled battery is placed in a 65°C oven for in-situ thermal polymerization for 12 h, and finally a solid sodium metal battery assembled with an in-situ crystalline framework composite paper-based cellulose solid gel electrolyte is obtained.

[0050] Example 2, the preparation method of solid sodium metal battery based on in-situ crystalline framework composite paper-based cellulose solid gel electrolyte assembly is as follows:

[0051] Step 1: Dissolve zinc sulfate heptahydrate in N,N-dimethylformamide (DMF) and ethanol, add tetramethylammonium bromide in an equimolar amount of zinc sulfate heptahydrate, and disperse it by sonication for 10 minutes to prepare a colorless and transparent solution A with a concentration of 0.125 mol / L;

[0052] Weigh out 5-methyltetrazole and dissolve it in N,N-dimethylformamide (DMF) and ethanol. Add tetramethylammonium bromide in an equimolar amount of 5-methyltetrazole and disperse it by sonication for 10 minutes to prepare a colorless and clear solution B with a concentration of 0.125 mol / L.

[0053] Step 2: Place a 6cm×6cm paper-based cellulose membrane on a 100℃ heating plate. The distance between the spray gun and the glass fiber is 10cm. Spray 20ml of solution A evenly with the spray gun. After standing for 20s, wash with ethanol. Then spray 20ml of solution B evenly with the spray gun. After standing for 20s, wash with ethanol. By spraying the membrane in situ layer by layer for 10 cycles, composite membrane C is obtained.

[0054] Step 3: At room temperature, the composite membrane C was immersed in ethanol for 10 hours, then removed and dried in a 100℃ oven to obtain the in-situ grown sulfate-enriched nitrile hybrid crystalline framework paper-based cellulose composite membrane D.

[0055] Step 4: Prepare the polymerization precursor solution in a glove box where the water and oxygen values ​​are both less than 0.01 ppm: Dissolve sodium tetrafluoroborate (NaBF4) in a mixed solvent of ethylene carbonate EC and dimethyl carbonate DMC with a volume ratio of 1:1, then add 5% fluoroethylene carbonate to the mixed solvent, and stir thoroughly for 30 minutes at room temperature under argon protection to obtain a prepolymerization precursor solution E with a sodium salt content of 1 mole;

[0056] Step 5: Add 1% by volume of 1,3-dioxolane (DOL) to the prepolymer precursor solution E obtained in Step 4, and then add the initiator azobisisobutyronitrile (AIBN) at a rate of 0.02% of the mass of DOL to obtain precursor solution F.

[0057] Step 6: In a glove box where the water and oxygen levels are both less than 0.01 ppm, 100 μL of the polymerization precursor solution F is dropped into the prepared sulfate-enriched nitrile hybrid crystalline framework paper-based cellulose composite membrane D. The battery is assembled with sodium vanadium phosphate as the positive electrode and metallic sodium as the negative electrode. The assembled battery is placed in a 65°C oven for in-situ thermal polymerization for 12 h, and finally a solid sodium metal battery assembled with an in-situ crystalline framework composite paper-based cellulose solid gel electrolyte is obtained.

[0058] Example 3, the preparation method of solid sodium metal battery based on in-situ crystalline framework composite paper-based cellulose solid gel electrolyte assembly is as follows:

[0059] Step 1: Dissolve zinc sulfate heptahydrate in N,N-dimethylformamide (DMF) and ethanol, add tetramethylammonium bromide in an equimolar amount of zinc sulfate heptahydrate, and disperse it by sonication for 6 minutes to prepare a colorless and transparent solution A with a concentration of 0.12 mol / L;

[0060] Weigh out 5-methyltetrazole and dissolve it in N,N-dimethylformamide (DMF) and ethanol. Add tetramethylammonium bromide in an equimolar amount of 5-methyltetrazole and disperse it by sonication for 6 minutes to prepare a colorless and clear solution B with a concentration of 0.12 mol / L.

[0061] Step 2: Place a 4cm×4cm paper-based cellulose membrane on a 90℃ heating plate. The distance between the spray gun and the glass fiber is 9cm. Spray 10ml of solution A evenly with the spray gun. After standing for 20s, wash with ethanol. Then spray 10ml of solution B evenly with the spray gun. After standing for 20s, wash with ethanol. By spraying the membrane in situ layer by layer for 10 cycles, composite membrane C is obtained.

[0062] Step 3: At room temperature, the composite membrane C was immersed in ethanol for 11 hours, then removed and dried in a 90°C oven to obtain the in-situ grown sulfate-enriched nitrile hybrid crystalline framework paper-based cellulose composite membrane D.

[0063] Step 4: Prepare the polymerization precursor solution in a glove box where the water and oxygen values ​​are both less than 0.01 ppm: Dissolve sodium tetrafluoroborate (NaBF4) in a mixed solvent of ethylene carbonate EC and dimethyl carbonate DMC with a volume ratio of 1:1, then add 5% fluoroethylene carbonate to the mixed solvent, and stir thoroughly for 30 minutes at room temperature under argon protection to obtain a prepolymerization precursor solution E with a sodium salt content of 1 mole;

[0064] Step 5: Add 1% by volume of 1,3-dioxolane (DOL) to the prepolymer precursor solution E obtained in Step 4, and then add the initiator azobisisobutyronitrile (AIBN) at a rate of 0.02% of the mass of DOL to obtain precursor solution F.

[0065] Step 6: In a glove box where the water and oxygen levels are both less than 0.01 ppm, 100 μL of the polymerization precursor solution F is dropped into the prepared sulfate-enriched nitrile hybrid crystalline framework paper-based cellulose composite membrane D. The battery is assembled with sodium vanadium phosphate as the positive electrode and metallic sodium as the negative electrode. The assembled battery is placed in a 70°C oven for in-situ thermal polymerization for 10 h, and finally a solid sodium metal battery assembled with an in-situ crystalline framework composite paper-based cellulose solid gel electrolyte is obtained.

[0066] Example 4: The preparation method of a solid sodium metal battery based on an in-situ crystalline framework composite paper-based cellulose solid gel electrolyte is as follows:

[0067] Step 1: Dissolve zinc sulfate heptahydrate in N,N-dimethylformamide (DMF) and ethanol, add tetramethylammonium bromide in an equimolar amount of zinc sulfate heptahydrate, and disperse it by sonication for 9 minutes to prepare a colorless and transparent solution A with a concentration of 0.1 mol / L;

[0068] Weigh out 5-methyltetrazole and dissolve it in N,N-dimethylformamide (DMF) and ethanol. Add tetramethylammonium bromide in an equimolar amount of 5-methyltetrazole and disperse it by sonication for 9 minutes to prepare a colorless and clear solution B with a concentration of 0.1 mol / L.

[0069] Step 2: Place a 10cm×10cm paper-based cellulose membrane on a 100℃ heating plate. The distance between the spray gun and the glass fiber is 8-10cm. Spray 10ml of solution A evenly with the spray gun. After standing for 20s, wash with ethanol. Then spray 10ml of solution B evenly with the spray gun. After standing for 20s, wash with ethanol. By spraying the membrane in situ layer by layer for 10 cycles, the composite membrane C is obtained.

[0070] Step 3: At room temperature, the composite membrane C was immersed in ethanol for 12 hours, then removed and dried in a 100℃ oven to obtain the in-situ grown sulfate-enriched nitrile hybrid crystalline framework paper-based cellulose composite membrane D.

[0071] Step 4: Prepare the polymerization precursor solution in a glove box where the water and oxygen values ​​are both less than 0.01 ppm: Dissolve sodium tetrafluoroborate (NaBF4) in a mixed solvent of ethylene carbonate EC and dimethyl carbonate DMC with a volume ratio of 1:1, then add 5% fluoroethylene carbonate to the mixed solvent, and stir thoroughly for 30 minutes at room temperature under argon protection to obtain a prepolymerization precursor solution E with a sodium salt content of 1 mole;

[0072] Step 5: Add 1% by volume of 1,3-dioxolane (DOL) to the prepolymer precursor solution E obtained in Step 4, and then add the initiator azobisisobutyronitrile (AIBN) at a rate of 0.02% of the mass of DOL to obtain precursor solution F.

[0073] Step 6: In a glove box where the water and oxygen levels are both less than 0.01 ppm, 100 μL of the polymerization precursor solution F is dropped into the prepared sulfate-enriched nitrile hybrid crystalline framework paper-based cellulose composite membrane D. The battery is assembled with sodium vanadium phosphate as the positive electrode and metallic sodium as the negative electrode. The assembled battery is placed in a 75°C oven for in-situ thermal polymerization for 12 h, and finally a solid sodium metal battery assembled with an in-situ crystalline framework composite paper-based cellulose solid gel electrolyte is obtained.

[0074] Example 5 describes the preparation method of a solid-state sodium metal battery assembled based on an in-situ crystalline framework composite paper-based cellulose solid gel electrolyte:

[0075] Step 1: Dissolve zinc sulfate heptahydrate in N,N-dimethylformamide (DMF) and ethanol, add tetramethylammonium bromide in an equimolar amount of zinc sulfate heptahydrate, and disperse it by sonication for 10 minutes to prepare a colorless and transparent solution A with a concentration of 0.125 mol / L;

[0076] Weigh out 5-methyltetrazole and dissolve it in N,N-dimethylformamide (DMF) and ethanol. Add tetramethylammonium bromide in an equimolar amount of 5-methyltetrazole and disperse it by sonication for 10 minutes to prepare a colorless and clear solution B with a concentration of 0.125 mol / L.

[0077] Step 2: Place a 6cm×6cm paper-based cellulose membrane on a 110℃ heating plate. The distance between the spray gun and the glass fiber is 8cm. Spray 20ml of solution A evenly with the spray gun. After standing for 20s, wash with ethanol. Then spray 20ml of solution B evenly with the spray gun. After standing for 20s, wash with ethanol. By spraying the membrane in situ layer by layer for 10 cycles, composite membrane C is obtained.

[0078] Step 3: At room temperature, the composite membrane C was immersed in ethanol for 12 hours, then removed and dried in a 100℃ oven to obtain the in-situ grown sulfate-enriched nitrile hybrid crystalline framework paper-based cellulose composite membrane D.

[0079] Step 4: Prepare the polymerization precursor solution in a glove box where the water and oxygen values ​​are both less than 0.01 ppm: Dissolve sodium tetrafluoroborate (NaBF4) in a mixed solvent of ethylene carbonate EC and dimethyl carbonate DMC with a volume ratio of 1:1, then add 5% fluoroethylene carbonate to the mixed solvent, and stir thoroughly for 30 minutes at room temperature under argon protection to obtain a prepolymerization precursor solution E with a sodium salt content of 1 mole;

[0080] Step 5: Add 1% by volume of 1,3-dioxolane (DOL) to the prepolymer precursor solution E obtained in Step 4, and then add the initiator azobisisobutyronitrile (AIBN) at a rate of 0.02% of the mass of DOL to obtain precursor solution F.

[0081] Step 6: In a glove box where the water and oxygen levels are both less than 0.01 ppm, 100 μL of the polymerization precursor solution F is dropped into the prepared sulfate-enriched nitrile hybrid crystalline framework paper-based cellulose composite membrane D. The battery is assembled with sodium vanadium phosphate as the positive electrode and metallic sodium as the negative electrode. The assembled battery is placed in a 65°C oven for in-situ thermal polymerization for 12 h, and finally a solid sodium metal battery assembled with an in-situ crystalline framework composite paper-based cellulose solid gel electrolyte is obtained.

[0082] Example 6: The preparation method of a solid-state sodium metal battery based on an in-situ crystalline framework composite paper-based cellulose solid gel electrolyte assembly is as follows:

[0083] Step 1: Dissolve zinc sulfate heptahydrate in N,N-dimethylformamide (DMF) and ethanol, add tetramethylammonium bromide in an equimolar amount of zinc sulfate heptahydrate, and disperse it by sonication for 6 minutes to prepare a colorless and transparent solution A with a concentration of 0.125 mol / L;

[0084] Weigh out 5-methyltetrazole and dissolve it in N,N-dimethylformamide (DMF) and ethanol. Add tetramethylammonium bromide in an equimolar amount of 5-methyltetrazole and disperse it by sonication for 6 minutes to prepare a colorless and clear solution B with a concentration of 0.125 mol / L.

[0085] Step 2: Place a 10cm×10cm paper-based cellulose membrane on a 110℃ heating plate. The distance between the spray gun and the glass fiber is 9cm. Spray 10ml of solution A evenly with the spray gun. After standing for 20s, wash with ethanol. Then spray 10ml of solution B evenly with the spray gun. After standing for 20s, wash with ethanol. By spraying the membrane in situ layer by layer for 10 cycles, composite membrane C is obtained.

[0086] Step 3: At room temperature, the composite membrane C was immersed in ethanol for 12 hours, then removed and dried in an oven at 110°C to obtain the in-situ grown sulfate-enriched nitrile hybrid crystalline framework paper-based cellulose composite membrane D.

[0087] Step 4: Prepare the polymerization precursor solution in a glove box where the water and oxygen values ​​are both less than 0.01 ppm: Dissolve sodium tetrafluoroborate (NaBF4) in a mixed solvent of ethylene carbonate EC and dimethyl carbonate DMC with a volume ratio of 1:1, then add 5% fluoroethylene carbonate to the mixed solvent, and stir thoroughly for 30 minutes at room temperature under argon protection to obtain a prepolymerization precursor solution E with a sodium salt content of 1 mole;

[0088] Step 5: Add 1% by volume of 1,3-dioxolane (DOL) to the prepolymer precursor solution E obtained in Step 4, and then add the initiator azobisisobutyronitrile (AIBN) at a rate of 0.02% of the mass of DOL to obtain precursor solution F.

[0089] Step 6: In a glove box where the water and oxygen levels are both less than 0.01 ppm, 120 μL of the polymerization precursor solution F is dropped into the prepared sulfate-enriched nitrile hybrid crystalline framework paper-based cellulose composite membrane D. The battery is assembled with sodium vanadium phosphate as the positive electrode and metallic sodium as the negative electrode. The assembled battery is placed in a 65°C oven for in-situ thermal polymerization for 12 h, and finally a solid sodium metal battery assembled with an in-situ crystalline framework composite paper-based cellulose solid gel electrolyte is obtained.

[0090] Example 1 is the best embodiment. The following are the experimental data of the product prepared in Example 1:

[0091] like Figure 2 As shown, the synthesized sulfate-rich hybrid azole crystalline framework AHF-SO4-2 exhibits a regular morphology under an electron microscope and is a stable two-dimensional layered crystalline framework.

[0092] like Figure 3 As shown, the diffraction peaks of the synthesized AHF-SO4-2 crystal are highly consistent with those of the standard card; simultaneously, in the infrared spectrum, the peaks at 1493 cm⁻¹ are also highly consistent. -1 1396cm -1 and 1128cm -1 Characteristic absorption peaks of N=N, CN and S=O bonds were detected at the respective locations, which together confirm the successful synthesis of AHF-SO4-2 crystal.

[0093] like Figure 4 The figure shows the thermogravimetric analysis curve of AHF-SO4-2 crystal. The curve shows no significant mass loss before 277℃, and only begins to decrease from 277℃, indicating that the synthesized AHF-SO4-2 crystal has good thermal stability.

[0094] like Figure 5The image shown is a SEM image of the paper-based cellulose composite membrane after spraying, which shows that AHF-SO4-2 crystals were successfully loaded in the membrane.

[0095] like Figure 6 As shown, the electrochemical window test of the assembled half-cell after the preparation of the in-situ crystalline framework composite paper-based cellulose solid gel electrolyte was carried out on an electrochemical workstation. It can be seen that the electrochemical window of the prepared membrane is 4.96V, which is a good electrochemical window.

[0096] like Figure 7 The figure shows the rate-of-charge (ROC) curves after 10 cycles at different current densities. The sodium metal battery assembled with an in-situ crystalline framework composite paper-based cellulose solid gel electrolyte exhibits charge-discharge specific capacities of 113, 108, 103, 95, and 87 mAh g⁻¹ at current densities of 0.1C, 0.2C, 0.5C, 1C, and 2C, respectively. -1 The efficiency is also close to 100%. This is because the synthesized sulfate-rich hybrid azole crystalline framework AHF-SO4-2 is a stable two-dimensional layered crystalline framework, in which SO4... 2 - The structure located beneath each layer constructs directional and stable ion channels for cation transport, while efficiently immobilizing anions such as BF4-, TFSI-, and ClO4-, thereby enhancing the free Na+ transport. + Migration efficiency.

[0097] like Figure 8 The figure shows the charge-discharge specific capacity and coulombic efficiency of a sodium metal battery assembled with an in-situ crystalline framework composite paper-based cellulose solid gel electrolyte at a 1C current density. It can be seen that the charge-discharge capacity at a high current density of 1C is 106 mAh g⁻¹. -1 After 600 cycles, its coulombic efficiency remains at 99%, and its capacity retention rate is at 90.5%.

[0098] 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 protection scope of the present invention.

Claims

1. A method for preparing a solid-state sodium metal battery based on an in-situ crystalline framework composite paper-based cellulose solid gel electrolyte assembly, characterized in that, By using in-situ rotary spraying, SO4-rich 2- The AHF-SO4-2 crystalline framework material was grown in situ on a paper-based fiber separator. A polymer electrolyte precursor solution was prepared by mixing sodium salt with DOL, a small molecule that can be polymerized in situ, and ether solvents. The solution was then heated in situ inside the battery to achieve in-situ thermal polymerization, ultimately resulting in a solid sodium metal battery assembled using an in-situ crystalline framework composite paper-based cellulose solid gel electrolyte.

2. The method for preparing a solid-state sodium metal battery based on an in-situ crystalline framework composite paper-based cellulose solid gel electrolyte assembly according to claim 1, characterized in that, The specific method is as follows: Step 1: Dissolve zinc sulfate heptahydrate in N,N-dimethylformamide (DMF) and ethanol, add tetramethylammonium bromide in an equimolar amount of zinc sulfate heptahydrate, and disperse it by ultrasound to prepare a colorless and transparent solution A with a concentration of 0.1-0.125 mol / L; Weigh out 5-methyltetrazole and dissolve it in N,N-dimethylformamide (DMF) and ethanol. Add tetramethylammonium bromide in an equimolar amount of 5-methyltetrazole and disperse it by ultrasound to prepare a colorless and clear solution B with a concentration of 0.1-0.125 mol / L. Step 2: Place the paper-based cellulose membrane on a heating plate, and use a spray gun to evenly spray solution A onto the paper-based cellulose membrane. After standing and stabilizing, wash with ethanol. Then use a spray gun to evenly spray solution B onto it. After standing and stabilizing, wash with ethanol to obtain composite membrane C. Step 3: At room temperature, the composite membrane C is immersed in ethanol, then removed and dried in an oven to obtain the in-situ grown sulfate-enriched nitrile hybrid crystalline framework paper-based cellulose composite membrane D. Step 4: Preparation of prepolymer precursor solution: Dissolve sodium salt in a mixed solvent of ethylene carbonate EC and dimethyl carbonate DMC, then add fluoroethylene carbonate, and stir thoroughly for 30 minutes at room temperature under inert gas protection to obtain prepolymer precursor solution E; Step 5: Add 1,3-dioxolane (DOL) to the prepolymer precursor solution E obtained in Step 4, and then add the initiator azobisisobutyronitrile (AIBN) to obtain the precursor solution F; Step 6: In a glove box where the water and oxygen levels are both less than 0.01 ppm, the precursor solution E is dropped into the prepared sulfate-enriched nitrogen-azole hybrid crystalline framework paper-based cellulose composite membrane D. The battery is assembled with sodium vanadium phosphate as the positive electrode and metallic sodium as the negative electrode. The battery is placed in an oven for in-situ thermal polymerization, and finally a solid sodium metal battery assembled with an in-situ crystalline framework composite paper-based cellulose solid gel electrolyte is obtained.

3. The method for preparing a solid-state sodium metal battery based on an in-situ crystalline framework composite paper-based cellulose solid gel electrolyte assembly according to claim 2, characterized in that, The ultrasound time in step 1 is 5-10 minutes.

4. The method for preparing a solid-state sodium metal battery based on an in-situ crystalline framework composite paper-based cellulose solid gel electrolyte assembly according to claim 2 or 3, characterized in that, In step 2, the temperature of the heating plate is 90-110℃, and the distance between the spray gun and the glass fiber is 10 cm.

5. The method for preparing a solid-state sodium metal battery based on an in-situ crystalline framework composite paper-based cellulose solid gel electrolyte assembly according to claim 4, characterized in that, In step 4, the sodium salt in the electrolyte is sodium tetrafluoroborate, and ethylene carbonate EC and dimethyl carbonate DMC with a volume ratio of 1:1 are added as a mixed solvent; then 5% by volume of fluoroethylene carbonate is added to the mixed solvent, and the mixture is stirred thoroughly for 30 minutes to obtain a prepolymer precursor solution E with a sodium salt concentration of 1 mole.

6. The method for preparing a solid-state sodium metal battery based on an in-situ crystalline framework composite paper-based cellulose solid gel electrolyte assembly according to claim 5, characterized in that, In step 3, the composite diaphragm C is immersed in ethanol for 12-24 hours.

7. The method for preparing a solid-state sodium metal battery based on an in-situ crystalline framework composite paper-based cellulose solid gel electrolyte assembly according to claim 6, characterized in that, In step 3, the oven drying temperature is 90-120℃.

8. The method for preparing a solid-state sodium metal battery based on an in-situ crystalline framework composite paper-based cellulose solid gel electrolyte assembly according to claim 7, characterized in that, In step 5, the amount of 1,3-dioxolane (DOL) added is 1% of the volume of the prepolymer precursor solution E, and the amount of initiator is 0.02% to 0.1% of 1,3-dioxolane (DOL).

9. The method for preparing a solid-state sodium metal battery based on an in-situ crystalline framework composite paper-based cellulose solid gel electrolyte assembly according to claim 8, characterized in that, In step 6, the battery is placed in an oven at 65-75℃ for in-situ thermal polymerization for 10-12 hours.

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