Inflammable sodium battery and preparation method thereof

Abstract

The invention relates to the technical field of new energy, in particular to a nonflammable sodium battery and a preparation method thereof. The invention discloses a preparation method of a nonflammable sodium battery. The preparation method comprises the following steps: S1, preparing a sulfide solid electrolyte membrane; s2, preparing a positive pole piece; s3, preparing a negative pole piece; and S4, assembling the battery to obtain the nonflammable sodium battery. According to the preparation method disclosed by the invention, through innovative design and process optimization, the nonflammable sodium battery with high safety, high critical current density and excellent cycle performance is successfully prepared, and the nonflammable sodium battery is applied to the fields of portable electronic equipment, electric automobiles, large-scale energy storage systems and the like.

Description

Technical Field

[0001] The present application relates to the field of new energy technology, and in particular to a non-flammable sodium battery and a preparation method thereof. Background Art

[0002] Sodium-ion battery is a secondary battery that mainly relies on the movement of sodium ions between the positive and negative electrodes to work. It is similar to the working principle of lithium-ion batteries and is one of the top ten emerging technologies in the field of chemistry in 2022. Sodium-ion batteries have attracted the attention of all parties and researchers due to their advantages such as abundant reserves and the same rocking chair storage mechanism, and are expected to become one of the candidates for large-scale energy storage devices in the future.

[0003] Although the sodium batteries currently on the market are low-cost and abundant in resources, they have great safety risks, especially under high temperature or overcharge conditions, and are prone to combustion accidents. Existing sodium-ion batteries usually use an organic electrolyte system. Although the battery under this system has a high energy density, its flammability has become a major bottleneck restricting its widespread application. With the increasing safety requirements for energy storage devices, the development of new non-flammable sodium batteries has become an urgent need in the industry. Summary of the invention

[0004] In order to solve the shortcomings existing in the prior art, the present application provides a non-flammable sodium battery and a preparation method thereof. The non-flammable sodium battery prepared by the present application has high safety, good critical current density and cycle performance. The preparation method of the present application eliminates the traditional electrolyte and replaces it with a sulfide solid electrolyte membrane, thereby avoiding the flammability problem of the traditional electrolyte and greatly improving the safety of the battery. At the same time, the traditional PE or PP diaphragm is eliminated, further improving the safety of the battery and avoiding the short circuit problem caused by sodium dendrites piercing the diaphragm.

[0005] In a first aspect, the present application provides a method for preparing a non-combustible sodium battery, using the following technical solution: A method for preparing a non-combustible sodium battery comprises the following steps: S1. preparing a sulfide solid electrolyte powder, grinding and mixing the sulfide solid electrolyte powder and a binder, and then transferring the powder to a roller press, and continuously rolling the powder to obtain a sulfide solid electrolyte membrane with a thickness of 10-30 μm; S2, mixing the positive electrode active material, the conductive agent and the binder A to obtain a positive electrode slurry; applying the positive electrode slurry to the surface of the positive electrode current collector, and vacuum drying to obtain a positive electrode sheet with an electrolyte layer having a thickness of 25-40 μm; S3, placing the sodium metal sheet in an argon environment, heating it to 60°C, then introducing PF3 reaction gas, reacting for 5-10 minutes, to obtain a negative electrode sheet; S4. The sulfide solid electrolyte membrane is arranged between the positive electrode plate and the negative electrode plate, and then isostatically pressed at a pressure of 300-350 MPa, the electrode ears are welded and packaged to obtain a sodium battery that is not easy to burn.

[0006] By adopting the above technical scheme, step S1: preparation of sulfide solid electrolyte membrane, this step is mainly to prepare sulfide solid electrolyte powder and mix and grind it with a binder. As a key component of sodium battery, sulfide solid electrolyte membrane provides an ion conduction path. At the same time, by selecting an appropriate binder and grinding process, the uniformity and stability of the electrolyte membrane are ensured. The use of this membrane not only improves the safety of the battery (because it is solid and non-flammable), but also improves the overall performance of the battery. Step S2: Preparation of positive electrode sheet, this step involves mixing the positive electrode material, conductive agent and binder A to form a positive electrode slurry. It is then coated on the positive electrode collector and dried. This ensures uniform distribution and high conductivity of the positive electrode material. At the same time, the vacuum drying process helps to eliminate any bubbles or impurities that may affect the performance of the battery. Step S3: Preparation of negative electrode sheet, in this step, the sodium metal sheet is heated in an argon environment and PF3 gas is introduced for reaction. This not only ensures the purity and stability of the sodium metal sheet, but also generates sodium-based inorganic substances that conduct sodium ions through surface treatment, thereby improving the performance of the battery. This treatment reduces the growth of sodium dendrites, thereby improving the safety and cycle stability of the battery. Step S4: Battery assembly, the last step is to set the sulfide solid electrolyte membrane between the positive electrode and the negative electrode. The close contact between the electrolyte membrane and the electrode is ensured by isostatic pressing. At the same time, welding the tabs and packaging ensure the structural integrity and long-term stability of the battery. Through this treatment, the safety of the battery is further improved. The use of sulfide solid electrolyte membrane replaces the flammable traditional electrolyte, while eliminating the use of flammable diaphragms, which significantly improves the safety of the battery. By precisely controlling the proportions of each component and the treatment process, such as the preparation of the positive electrode slurry and the surface treatment of the negative electrode metal sheet, the high critical current density and good cycle performance of the battery are ensured. By generating sodium-based inorganic substances that conduct sodium ions on the surface of the negative electrode sheet, the interface impedance and sodium ion field distribution problems between the sulfide solid electrolyte membrane and the sodium metal negative electrode sheet are improved, thereby improving the overall performance and stability of the battery. In summary, these steps not only play a key role each, but also work together to ensure the high safety, high performance and long life of the battery through synergy.

[0007] Preferably, the chemical composition of the sulfide solid electrolyte powder is Na 2.9 W 0.3 Sb 0.7 S4.

[0008] Preferably, the method for preparing the sulfide solid electrolyte powder comprises the following steps: S31. In an argon gas environment, weigh raw materials Na2S, Sb2S3, WS2 and S in a stoichiometric ratio, mix them, perform wet ball milling, and then perform vacuum drying to obtain a sulfide solid electrolyte precursor; S32, the sulfide solid electrolyte precursor is pressed into a sheet at a pressure of 500-600 MPa for 2-3 minutes, and then vacuum high-temperature sintered. After cooling to room temperature, the sheet is ground and passed through an 800-mesh sieve to obtain a sulfide solid electrolyte powder.

[0009] By adopting the above technical solution, the chemical composition of the sulfide solid electrolyte powder is Na 2.9 W 0.3 Sb 0.7 S4, this composition can improve the air stability and mechanical properties of the material while ensuring high ionic conductivity by optimizing the element ratio.

[0010] Preferably, in step S31, the wet ball milling is performed using a planetary ball mill, agate balls are used as grinding balls, the ball-to-material mass ratio is (10-13):1, the ball milling speed is 300-350rpm, and the ball milling time is 7-9h; ethanol is used as the solvent during ball milling, and the amount of ethanol is 15-20% of the total mass of Na2S, Sb2S3, WS2 and S; the vacuum drying temperature is 60-80°C, and the drying time is 8-12h.

[0011] Preferably, in step S32, the vacuum high temperature sintering is performed by heating the temperature to 400-600°C at a rate of 1-3°C / min and keeping the temperature for 20-25h.

[0012] Preferably, in step S1, the mass ratio of the sulfide solid electrolyte powder to the binder is 100:9.5; the rolling conditions are: the rolling temperature is 130-160° C., and the speed of the pressing roller is 15-40 rpm.

[0013] Preferably, in step S1, the preparation method of the binder is: mixing hydrogenated nitrile rubber and styrene butadiene rubber with butyl butyrate in a mass ratio of 5:4, and dissolving to obtain a binder with a solid content of 3-5%.

[0014] By adopting the above technical scheme, the prepared binder is used to bond the sulfide solid electrolyte powder together to form a uniform and stable electrolyte membrane. The combination of hydrogenated nitrile rubber (HNBR) and styrene butadiene rubber (SBR) has a high bonding strength, ensuring that the electrolyte membrane will not crack or delaminate during rolling and subsequent processing. By selecting a suitable binder, the ionic conductivity of the sulfide solid electrolyte membrane can be improved. The combination of HNBR and SBR not only has good mechanical properties, but also promotes the migration of ions in the electrolyte membrane. The sulfide solid electrolyte membrane undergoes multiple charges and discharges during battery operation, and needs to have a certain flexibility to adapt to volume changes. The combination of HNBR and SBR can improve the flexibility of the electrolyte membrane while ensuring the bonding strength, and prevent the membrane from rupture due to repeated charging and discharging. Synergistic effect between hydrogenated nitrile rubber and styrene butadiene rubber: HNBR has high bonding strength and chemical corrosion resistance, while SBR has good processing performance and low cost. The combination of the two can reduce production costs and improve processing performance while ensuring bonding strength. HNBR performs well in ion conduction, while SBR has good mechanical properties. The synergistic effect of the two can balance the ionic conductivity and mechanical properties, so that the electrolyte membrane has sufficient mechanical strength while maintaining high ionic conductivity. HNBR has good flexibility and elasticity, while SBR can provide additional flexibility and processing performance. The combination of the two enables the electrolyte membrane to better adapt to volume changes during charging and discharging, reducing membrane rupture caused by stress concentration. In summary, by mixing hydrogenated nitrile rubber and styrene butadiene rubber with butyl butyrate in a mass ratio of 5:4, the binder prepared can not only improve the bonding strength and ionic conductivity of the sulfide solid electrolyte membrane, but also improve its flexibility, thereby ensuring the safety and high performance of the sodium battery.

[0015] Preferably, in step S2, the positive electrode active material is Na3V2(PO4)3 and Na3Zr2Si2PO 12 The composition comprises: the particle size range of the positive electrode active material particles is 100-250nm; the conductive agent is the conductive agent Super P; the binder A is polytetrafluoroethylene; the positive electrode current collector is aluminum foil; and the solid content of the positive electrode slurry is 40-50%.

[0016] Preferably, in step S2, the mass ratio of the positive electrode active material, the conductive agent and the binder A is (76-84):(8-12):(8-12).

[0017] In a second aspect, the present application provides a non-flammable sodium battery, which adopts the following technical solution: As a general technical concept, the present application also provides the above-mentioned non-combustible sodium battery, which is prepared by the above-mentioned preparation method of the non-combustible sodium battery.

[0018] In summary, the beneficial technical effects of this application are: 1. Significantly improve safety: The use of sulfide solid electrolyte membranes to replace traditional flammable liquid electrolytes eliminates safety hazards caused by electrolyte leakage. The traditional PE or PP separators are eliminated, further improving the safety of the battery and avoiding the short circuit problem caused by sodium dendrites piercing the separator. By generating sodium-based inorganic substances that conduct sodium ions on the surface of the negative electrode, the interface impedance between the sulfide solid electrolyte membrane and the sodium metal negative electrode is improved, reducing the growth of sodium dendrites, thereby improving the safety of the battery.

[0019] 2. Optimize battery performance: By precisely controlling the proportions of each component and the processing technology, such as the preparation of the positive electrode slurry and the surface treatment of the negative electrode metal sheet, the high critical current density of the battery is ensured. The sodium-based inorganic substances that conduct sodium ions generated by the surface treatment of the negative electrode sheet improve the interface impedance and sodium ion field distribution between the sulfide solid electrolyte membrane and the sodium metal negative electrode sheet, thereby improving the battery's cycle performance.

[0020] 3. Enhance the performance of the electrolyte membrane: By selecting a specific type of binder (such as a combination of hydrogenated nitrile rubber HNBR and styrene butadiene rubber SBR) and regulating the ratio of the two, the prepared sulfide solid electrolyte membrane not only has a high bonding strength, but also further improves the ionic conductivity and flexibility. The prepared sulfide solid electrolyte membrane has high ionic conductivity and air stability, and can remain in the air for a long time without significant degradation. Through a continuous rolling process, a sulfide solid electrolyte membrane with a thickness of 10-30μm is prepared, ensuring the uniformity and stability of the membrane. DETAILED DESCRIPTION

[0021] The embodiments of the present application will be described in detail below in conjunction with the examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. In the examples, if specific conditions are not specified, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0022] Preparation Example 1 Sulfide solid electrolyte powder (Na 2.9 W 0.3 Sb 0.7 Preparation of S4) Sulfide solid electrolyte powder (Na 2.9 W 0.3 Sb 0.7 S4) preparation method, comprising the following steps: S31. In an argon gas environment, weigh the raw materials Na2S, Sb2S3, WS2 and S in a stoichiometric ratio, mix them, and perform wet ball milling, and then perform vacuum drying to obtain a sulfide solid electrolyte precursor; the wet ball milling is performed using a planetary ball mill, agate balls are used as grinding balls, the ball-to-material mass ratio is 11:1, the ball milling speed is 330 rpm, and the ball milling time is 8 h; ethanol is used as a solvent during ball milling, and the amount of ethanol used is 17% of the total mass of Na2S, Sb2S3, WS2 and S; the vacuum drying temperature is 70°C, and the drying time is 10 h; S32. The sulfide solid electrolyte precursor is pressed into a tablet at a pressure of 550 MPa for 2.5 minutes, and then vacuum high-temperature sintering is performed. After cooling to room temperature, the powder is ground and passed through an 800-mesh sieve to obtain a sulfide solid electrolyte powder. The vacuum high-temperature sintering is performed by heating the powder to 500°C at a rate of 2°C / min and keeping the temperature for 23 hours.

[0023] Example 1 A method for preparing a non-combustible sodium battery comprises the following steps: S1. Prepared sulfide solid electrolyte powder (Na 2.9 W 0.3 Sb 0.7 S4) and a binder are ground and mixed at a mass ratio of 100:9.5, and then transferred to a roller press, and continuously rolled at a rolling temperature of 130°C and a roller speed of 15 rpm to obtain a sulfide solid electrolyte membrane with a thickness of 20 μm; wherein the preparation method of the binder is: hydrogenated nitrile rubber and styrene-butadiene rubber are mixed with butyl butyrate according to a mass ratio of 5:4, and a binder with a solid content of 3% is obtained after dissolution; S2. Combine Na3V2(PO4)3, Na3Zr2Si2PO 12 , Super P and polytetrafluoroethylene in a mass ratio of 50:30:10:10, and then NMP solvent is added for homogenization to obtain a positive electrode slurry with a solid content of 45%, and the positive electrode slurry is coated on the upper surface of the positive electrode current collector (Al foil), and vacuum dried to obtain a positive electrode sheet with an electrolyte layer thickness of 30 μm; S3, placing a sodium metal sheet with a thickness of 0.45 mm in an argon environment, heating it to 60°C, then introducing PF3 reaction gas, reacting for 5 minutes, to obtain a negative electrode sheet; S4. The sulfide solid electrolyte membrane is arranged between the positive electrode plate and the negative electrode plate, and then isostatically pressed, the electrode ears are welded and packaged at a pressure of 300 MPa to obtain a sodium battery that is not easy to burn.

[0024] Example 2 A method for preparing a non-combustible sodium battery comprises the following steps: S1. Prepared sulfide solid electrolyte powder (Na 2.9 W 0.3 Sb 0.7 S4) and a binder are ground and mixed at a mass ratio of 100:9.5, and then transferred to a roller press, and continuously rolled at a rolling temperature of 160°C and a roller speed of 40rpm to obtain a sulfide solid electrolyte membrane with a thickness of 20 μm; wherein the preparation method of the binder is: hydrogenated nitrile rubber and styrene-butadiene rubber are mixed with butyl butyrate according to a mass ratio of 5:4, and a binder with a solid content of 5% is obtained after dissolution; S2. Combine Na3V2(PO4)3, Na3Zr2Si2PO 12 , Super P and binder A polytetrafluoroethylene are mixed in a mass ratio of 50:30:10:10, and NMP solvent is added for homogenization to obtain a positive electrode slurry with a solid content of 45%, and the positive electrode slurry is coated on the upper surface of the positive electrode collector (Al foil), and vacuum dried to obtain a positive electrode sheet with an electrolyte layer thickness of 30 μm; S3, placing a sodium metal sheet with a thickness of 0.45 mm in an argon environment, heating it to 60°C, then introducing PF3 reaction gas, reacting for 10 minutes, and obtaining a negative electrode sheet; S4. The sulfide solid electrolyte membrane is arranged between the positive electrode plate and the negative electrode plate, and then isostatically pressed, the electrode ears are welded and packaged at a pressure of 350 MPa to obtain a sodium battery that is not easy to burn.

[0025] Example 3 A method for preparing a non-combustible sodium battery comprises the following steps: S1. Prepared sulfide solid electrolyte powder (Na 2.9 W 0.3 Sb 0.7 S4) and a binder are ground and mixed at a mass ratio of 100:9.5, and then transferred to a roller press, and continuously rolled at a rolling temperature of 140°C and a roller speed of 25 rpm to obtain a sulfide solid electrolyte membrane with a thickness of 20 μm; wherein the preparation method of the binder is: hydrogenated nitrile rubber and styrene-butadiene rubber are mixed with butyl butyrate according to a mass ratio of 5:4, and a binder with a solid content of 4% is obtained after dissolution; S2. Combine Na3V2(PO4)3, Na3Zr2Si2PO 12 , Super P and binder A polytetrafluoroethylene are mixed in a mass ratio of 50:30:10:10, and NMP solvent is added for homogenization to obtain a positive electrode slurry with a solid content of 45%, and the positive electrode slurry is coated on the upper surface of the positive electrode collector (Al foil), and vacuum dried to obtain a positive electrode sheet with an electrolyte layer thickness of 30 μm; S3, placing a sodium metal sheet with a thickness of 0.45 mm in an argon environment, heating it to 60°C, then introducing PF3 reaction gas, reacting for 8 minutes, to obtain a negative electrode sheet; S4. The sulfide solid electrolyte membrane is arranged between the positive electrode plate and the negative electrode plate, and then isostatically pressed at a pressure of 330 MPa, the electrode ears are welded and packaged to obtain a sodium battery that is not easy to burn.

[0026] Comparative Example 1 The same as Example 3, except that: in step S1, the preparation method of the binder is: hydrogenated nitrile rubber and butyl butyrate are mixed and dissolved to obtain a binder with a solid content of 4%.

[0027] Comparative Example 2 The same as Example 3, except that: in step S1, the preparation method of the binder is: styrene-butadiene rubber and butyl butyrate are mixed and dissolved to obtain a binder with a solid content of 4%.

[0028] Comparative Example 3 The same as Example 3, except that: in step S3, a sodium metal sheet with a thickness of 0.45MM is used as the negative electrode sheet.

[0029] Performance Testing Symmetrical batteries were prepared by respectively performing "disposing the sulfide solid electrolyte membrane between the positive electrode sheet and the negative electrode sheet" in step 4 of Examples 1 to 3 and Comparative Examples 1 to 3, and placed at 80° C. for 4 h for critical current density testing; the test results are shown in Table 1.

[0030] The non-flammable sodium batteries prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were subjected to charge and discharge cycle performance tests under 0.3C / 0.3C conditions, and the number of cycles when the battery capacity decayed to 80% of the initial capacity was recorded. The performance test results are shown in Table 1.

[0031] Table 1 Performance test results Analyzing the data in Table 1, we can see that: 1) The non-flammable sodium battery prepared in Examples 1 to 3 has high safety, good critical current density and cycle performance. The preparation method of the present application eliminates the traditional electrolyte and replaces it with a sulfide solid electrolyte membrane, thereby avoiding the flammability problem of the traditional electrolyte and greatly improving the safety of the battery. At the same time, the traditional PE or PP separator is eliminated, further improving the safety of the battery and avoiding the short circuit problem caused by sodium dendrites piercing the separator.

[0032] 2) The performance comparison analysis of the non-flammable sodium battery prepared in Example 3 and Comparative Examples 1-2 shows that the preparation method of the binder is: hydrogenated nitrile rubber and styrene butadiene rubber are mixed with butyl butyrate according to a mass ratio of 5:4, and a binder with a solid content of 4% is obtained after dissolution. The prepared binder is used to bond the sulfide solid electrolyte powder together to form a uniform and stable electrolyte membrane. The combination of hydrogenated nitrile butadiene rubber (HNBR) and styrene butadiene rubber (SBR) has a high bonding strength, ensuring that the electrolyte membrane will not crack or delaminate during rolling and subsequent processing. The combination of HNBR and SBR not only has good mechanical properties, but also promotes the migration of ions in the electrolyte membrane. The sulfide solid electrolyte membrane will undergo multiple charge and discharge during the operation of the battery, and needs to have a certain flexibility to adapt to volume changes. The combination of HNBR and SBR can improve the flexibility of the electrolyte membrane while ensuring the bonding strength, and prevent the membrane from rupture due to repeated charge and discharge. By mixing hydrogenated nitrile rubber and styrene butadiene rubber with butyl butyrate in a mass ratio of 5:4, the prepared binder can not only improve the bonding strength and ionic conductivity of the sulfide solid electrolyte membrane, but also improve its flexibility, thereby ensuring the safety and high performance of the sodium battery.

[0033] 3) The performance comparison analysis of the non-flammable sodium battery prepared in Example 3 and Comparative Example 3 shows that in step S3: preparation of the negative electrode sheet, the sodium metal sheet is heated in an argon environment and PF3 gas is introduced for reaction. This not only ensures the purity and stability of the sodium metal sheet, but also generates sodium-based inorganic substances that conduct sodium ions through surface treatment, thereby improving the performance of the battery. This treatment reduces the growth of sodium dendrites, thereby improving the safety and cycle stability of the battery.

[0034] The above embodiments are only used to explain the technical solutions of the present application rather than to limit them. Although the above embodiments provide a specific description of the present application, relevant technical personnel should understand that the specific implementation methods of the present application can still be modified or replaced by equivalents, and any modifications and equivalent replacements that do not depart from the spirit and scope of the present application should be included in the protection scope of the present application.

Claims

1. A method for preparing a non-combustible sodium battery, characterized in that: The following steps are involved: S1. preparing a sulfide solid electrolyte powder, grinding and mixing the sulfide solid electrolyte powder and a binder, and then transferring the powder to a roller press, and continuously rolling the powder to obtain a sulfide solid electrolyte membrane with a thickness of 10-30 μm; S2, mixing the positive electrode active material, the conductive agent and the binder A to obtain a positive electrode slurry; applying the positive electrode slurry to the surface of the positive electrode current collector, and vacuum drying to obtain a positive electrode sheet with an electrolyte layer having a thickness of 25-40 μm; S3, placing the sodium metal sheet in an argon environment, heating it to 60°C, then introducing PF3 reaction gas, reacting for 5-10 minutes, to obtain a negative electrode sheet; S4. The sulfide solid electrolyte membrane is arranged between the positive electrode plate and the negative electrode plate, and then isostatically pressed at a pressure of 300-350 MPa, the electrode ears are welded and packaged to obtain a sodium battery that is not easy to burn.

2. The method for preparing a non-combustible sodium battery according to claim 1, characterized in that: In step S1, the chemical composition of the sulfide solid electrolyte powder is Na 2.9 W 0.3 Sb 0.7 S4.

3. The method for preparing a non-combustible sodium battery according to claim 2, characterized in that: The method for preparing the sulfide solid electrolyte powder comprises the following steps: S31. In an argon gas environment, weigh raw materials Na2S, Sb2S3, WS2 and S in a stoichiometric ratio, mix them, perform wet ball milling, and then perform vacuum drying to obtain a sulfide solid electrolyte precursor; S32, the sulfide solid electrolyte precursor is pressed into a sheet at a pressure of 500-600 MPa for 2-3 minutes, and then vacuum high-temperature sintered. After cooling to room temperature, the sheet is ground and passed through an 800-mesh sieve to obtain a sulfide solid electrolyte powder.

4. The method for preparing a non-combustible sodium battery according to claim 3, characterized in that: In step S31, the wet ball milling is performed using a planetary ball mill, agate balls are used as grinding balls, the ball-to-material mass ratio is (10-13):1, the ball milling speed is 300-350rpm, and the ball milling time is 7-9h; ethanol is used as the solvent during ball milling, and the amount of ethanol is 15-20% of the total mass of Na2S, Sb2S3, WS2 and S; the vacuum drying temperature is 60-80°C, and the drying time is 8-12h.

5. The method for preparing a non-combustible sodium battery according to claim 3, characterized in that: In step S32, the vacuum high temperature sintering is to increase the temperature to 400-600°C at a rate of 1-3°C / min and keep the temperature for 20-25h.

6. The method for preparing a non-combustible sodium battery according to claim 1, characterized in that: In step S1, the mass ratio of the sulfide solid electrolyte powder to the binder is 100:9.5; the rolling conditions are: the rolling temperature is 130-160° C., and the speed of the pressing roller is 15-40 rpm.

7. The method for preparing a non-combustible sodium battery according to claim 1, characterized in that: In step S1, the preparation method of the binder is: hydrogenated nitrile rubber and styrene butadiene rubber are mixed with butyl butyrate according to a mass ratio of 5:4, and the binder with a solid content of 3-5% is obtained after dissolving.

8. The method for preparing a non-combustible sodium battery according to claim 1, characterized in that: In step S2, the positive electrode active material is composed of Na3V2(PO4)3 and Na3Zr2Si2PO 12 The composition is as follows: the particle size range of the positive electrode active material particles is 100-250nm; the conductive agent is the conductive agent Super P; the binder A is polytetrafluoroethylene; the positive electrode current collector is aluminum foil; and the solid content of the positive electrode slurry is 40-50%.

9. The method for preparing a non-combustible sodium battery according to claim 1, characterized in that: In step S2, the mass ratio of the positive electrode active material, the conductive agent and the binder A is (76-84): (8-12): (8-12).

10. A non-combustible sodium battery, characterized in that: The non-combustible sodium battery is prepared by the preparation method of the non-combustible sodium battery according to any one of claims 1 to 9.

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