Sodium metal battery, sodium metal battery electrolyte and preparation method and application thereof
By using sulfite esters and film-forming additives in the electrolyte of sodium metal batteries, an inorganic-based SEI is formed, which solves the problem of poor electrolyte stability, achieves high-efficiency cycle performance and stability of sodium metal batteries, and expands their application prospects.
Patent Information
- Application Number
- CN202511110884.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-08
- Publication Date
- 2025-11-11
AI Technical Summary
Existing sodium metal battery electrolytes, when using ester and ether solvents, are prone to dendrite growth and side reactions, exhibit poor oxidation stability, and cannot be matched with high-voltage cathodes, thus limiting the widespread application of sodium metal batteries.
Sulfite containing –SO3 groups is used as the main solvent, and film-forming additives such as fluoroethylene carbonate and vinylene carbonate are added to optimize the electrolyte formulation and form a solid electrolyte interphase (SEI) film mainly composed of inorganic components, thereby improving the stability and cycle performance of the electrolyte.
By optimizing the electrolyte composition, the cycle stability and reversibility of sodium metal batteries are significantly improved, thereby enhancing the cycle life and electrochemical performance of the batteries and meeting the needs of large-scale application of sodium metal batteries.
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Figure CN120933438A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of energy storage battery technology, specifically to a sodium metal battery, a sodium metal battery electrolyte, its preparation method, and its application. Background Technology
[0002] Sodium metal batteries possess advantages such as high theoretical capacity (1166 mAh / g), relatively low redox potential (2.71 V), long cycle life, environmental friendliness, and cost-effectiveness, making them a promising candidate for large-scale applications in energy storage. To ensure robust and safe operation in practical applications, the electrolyte plays a crucial role. Existing electrolytes typically use ester and ether solvents. Carbonate electrolytes can exacerbate dendrite growth, leading to severe side reactions, while ether electrolytes, due to their poor oxidative stability, cannot be matched with high-voltage cathodes.
[0003] Therefore, the urgent technical problem to be solved is to develop an electrolyte with excellent overall performance to improve the widespread application of sodium metal batteries. Summary of the Invention
[0004] This invention is made to solve the above-mentioned problems, and its purpose is to provide a sodium metal battery, a sodium metal battery electrolyte, a preparation method thereof, and its application.
[0005] This invention provides a sodium metal battery electrolyte, characterized by comprising: an organic solvent, a sodium electrolyte salt, and a film-forming additive, wherein the organic solvent is a sulfite containing a –SO3 group, and the volume of the sulfite accounts for 90-98% of the volume of the sodium metal battery electrolyte.
[0006] The sodium metal battery electrolyte provided by this invention may also have the following characteristics: the sulfite includes cyclic sulfite and chain sulfite, the cyclic sulfite includes at least one of vinyl sulfite, propylene sulfite and 4-methylvinyl sulfite, the volume of the cyclic sulfite accounts for 30% to 80% of the volume of the sodium-ion battery electrolyte, and the chain sulfite includes at least one of dimethyl sulfite, diethyl sulfite and dipropyl sulfite, the volume of the chain sulfite accounts for 10% to 60% of the volume of the sodium metal battery electrolyte.
[0007] The sodium metal battery electrolyte provided by the present invention may also have the following characteristics: wherein the film-forming additive is at least one of fluoroethylene carbonate, vinylene carbonate and 1,3-propanesulfonyl lactone, and the volume of the film-forming additive accounts for 2 to 10% of the volume of the sodium metal battery electrolyte.
[0008] The sodium metal battery electrolyte provided by the present invention may also have the following characteristics: wherein the electrolyte sodium salt is one or more of sodium perchlorate, sodium hexafluorophosphate, sodium bis(fluorosulfonyl)imide, sodium bis(trifluoromethylsulfonyl)imide, and sodium trifluoromethylsulfonate.
[0009] The sodium metal battery electrolyte provided by the present invention may also have the following characteristic: the concentration of the electrolyte sodium salt in the sodium metal battery electrolyte is 0.5 to 1.5 mol / L.
[0010] The sodium metal battery electrolyte provided by this invention may also have the following characteristic: the density of the sodium metal battery electrolyte is 1.0 to 1.5 g / cm³. 3 Its electrical conductivity is 6–12 mS / cm.
[0011] The present invention also provides a method for preparing a sodium metal battery electrolyte, characterized in that the preparation method includes: dissolving an electrolyte sodium salt in an organic solvent and then adding it to a mixed solvent prepared by a film-forming additive to obtain the sodium metal battery electrolyte.
[0012] This invention also provides an application of sodium metal battery electrolyte in the preparation of sodium metal batteries.
[0013] The present invention also provides a sodium metal battery, characterized by comprising: the sodium metal battery electrolyte described above, a current collector, and a sodium sheet.
[0014] The role and effect of invention
[0015] According to the present invention, a sodium metal battery, a sodium metal battery electrolyte, a method for preparing the electrolyte, and its application, the average viscosity of the electrolyte is reduced by using a low-melting-point, low-viscosity, and highly solvating sulfite solvent, thereby forming an inorganic-based SEI and improving the cycle performance of the sodium metal battery. In addition to the aforementioned solvent, the present invention also introduces film-forming additives to further optimize the electrolyte formulation and improve the cycle stability of the sodium metal battery.
[0016] In this invention, the cycle stability of sodium metal batteries is improved by rationally optimizing the ratio of organic solvent, sodium salt, and film-forming additives. Cycle stability is crucial for the large-scale application of sodium metal batteries. This invention addresses the shortcomings of commercially available electrolyte formulations that often fail to meet these requirements by providing a technical solution. By mixing organic solvent, sodium electrolyte salt, and film-forming additives in a specific ratio, this invention yields an electrolyte with high ionic conductivity and good stability, thus meeting the needs of sodium metal batteries.
[0017] The sodium metal battery electrolyte provided in this application is prepared by dissolving sodium salt in cyclic and chain sulfites, followed by the addition of film-forming additives. On one hand, sulfites possess strong solvation capabilities, increasing cation-solvent coordination; on the other hand, sulfites promote rapid SEI formation, with the formed SEI primarily composed of inorganic components, significantly improving SEI stability. This application utilizes organic solvents with various sulfite structures, solving the instability of existing SEIs while exhibiting excellent cycle life. This results in excellent reversibility and cycle stability at room temperature, making the fabricated sodium metal battery a promising candidate for a wide range of applications. Attached Figure Description
[0018] Figure 1 This is a coulombic efficiency diagram of a Na|Cu half-cell prepared with the electrolyte provided in Example 1 of the present invention at 25°C.
[0019] Figure 2 This is a charge-discharge voltage-time diagram at 25°C for a Na|Na symmetric battery made with an electrolyte provided in an embodiment of the present invention.
[0020] Figure 3 This is a capacity-voltage curve of a Na|NFM full cell prepared with the electrolyte provided in the embodiments of the present invention at 25°C; and
[0021] Figure 4 This is a cycling performance graph of a Na|NFM full cell made with the electrolyte provided in the embodiments of the present invention at 25°C. Detailed Implementation
[0022] To make the technical means, creative features, objectives and effects of the present invention easy to understand, the following embodiments, in conjunction with the accompanying drawings, specifically illustrate a sodium metal battery, a sodium metal battery electrolyte, its preparation method and application.
[0023] Example 1
[0024] A sodium metal battery electrolyte, wherein the concentrations of each component in the electrolyte are as follows:
[0025] The volume ratio of cyclic sulfites is 45% (ethylene sulfite), the volume ratio of chain sulfites is 45% (diethyl sulfite), the volume ratio of film-forming additives is 10% (ethylene fluorocarbonate), and the concentration of electrolyte sodium salt is 1 mol / L (sodium hexafluorophosphate).
[0026] The electrolyte preparation process was carried out in a glove box filled with argon (O2<0.1PPM, H2O<0.1PPM). The sodium electrolyte salt was dissolved in the solvent of the above proportion and stirred slowly at room temperature for 10 hours to obtain sodium metal battery electrolyte Example 1.
[0027] To verify the electrochemical performance of the electrolyte prepared in this embodiment, electrochemical tests were performed on the electrolyte prepared in this embodiment.
[0028] This application uses a 2032 button cell as the battery model, copper foil as the current collector, cut into circular pieces with a diameter of not less than 10 mm as electrode pieces, and vacuum dried at 80°C for 6 h as the working electrode. Sodium sheet is used as the negative electrode, and the electrolyte prepared above is used as the electrolyte. Na|Cu half cell is assembled and electrochemical performance is tested.
[0029] Figure 1 This is a coulombic efficiency diagram of a Na|Cu half-cell prepared with the electrolyte provided in Example 1 of the present invention at 25°C.
[0030] according to Figure 1 It can be seen that the coulombic efficiency plot (horizontal axis: cycle number, vertical axis: coulombic efficiency) of the Na|Cu half-cell prepared with the sodium metal battery electrolyte of Example 1 shows that the current density is 0.5 mA cm⁻¹ at 25°C. –2 1mAh cm –2 The electrolyte exhibits a coulombic efficiency of approximately 95% over 100 cycles, indicating excellent reversibility of the electrolyte with respect to sodium metal.
[0031] This application uses sodium sheets as the working electrode and negative electrode, and the electrolyte prepared above as the electrolyte to assemble a Na|Na symmetric cell and conduct electrochemical performance tests.
[0032] Figure 2 This is a charge / discharge voltage-time diagram at 25°C for a Na|Na symmetric battery made with an electrolyte provided in an embodiment of the present invention.
[0033] according to Figure 2 It can be seen from the charge / discharge voltage-time graph of the Na|Na symmetric battery prepared with the sodium metal battery electrolyte of Example 1 at 25°C that the sodium metal battery electrolyte of Example 1 clearly shows that the charge / discharge voltage-time at 1 mA cm⁻¹ is significantly lower than that of the Na|Na symmetric battery prepared with the sodium metal battery electrolyte of Example 1. –2 1mAh cm –2 The electrolyte exhibits excellent cycling stability, having cycled stably for over 1000 hours at a given current density.
[0034] This application uses a 100μm sodium sheet as the negative electrode with an N / P ratio of 4.3 and a 20mg cm⁻¹ electrode. –2 Using sodium nickel manganese ferrite as the positive electrode, a full cell was assembled using Na|NFM prepared with the sodium metal battery electrolyte of Example 1 and subjected to charge-discharge tests at 25°C.
[0035] Figure 3This is a capacity-voltage curve of a Na|NFM full cell made with the electrolyte provided in an embodiment of the present invention at 25°C.
[0036] according to Figure 3 It can be seen that when the sodium metal battery electrolyte of Example 1 is assembled into a full cell (horizontal axis: discharge capacity, vertical axis: voltage), under the condition of controlling the N / P ratio at 4.3, the capacity and voltage do not decrease much after 450 cycles, which fully demonstrates the stability of the electrolyte.
[0037] Figure 4 This is a cycling performance graph of a Na|NFM full cell made with the electrolyte provided in the embodiments of the present invention at 25°C.
[0038] according to Figure 4 It can be seen that when the sodium metal battery electrolyte of Example 1 is assembled into a full cell (x-axis: Cycle number, y-axis: Coulombic efficiency, Discharge capacity), with an N / P ratio controlled at 4.3, the full cell can withstand 450 cycles of charging at 0.5C and discharging at 1C while maintaining 85% of its capacity. This test result once again proves that the sodium metal battery electrolyte of Example 1 exhibits extremely high cycle stability.
[0039] Example 2:
[0040] This embodiment discloses a sodium metal battery electrolyte, which differs from Embodiment 1 in that the concentrations of each component in this electrolyte are as follows:
[0041] The volume ratio of cyclic sulfites is 45% (ethylene sulfite), the volume ratio of chain sulfites is 45% (dimethyl sulfite), the volume ratio of film-forming additives is 10% (ethylene fluorocarbonate), and the concentration of electrolyte sodium salt is 1 mol / L (sodium hexafluorophosphate).
[0042] The electrolyte preparation process was carried out in an argon-filled glove box (O2 < 0.1 PPM, H2O < 0.1 PPM). The sodium electrolyte salt was dissolved in the solvent of the above proportions, and the mixture was slowly stirred at room temperature for 10 hours to obtain the sodium metal battery electrolyte of Example 2. The cycle performance of this electrolyte is weaker than that of Example 1.
[0043] Example 3:
[0044] This embodiment discloses a sodium metal battery electrolyte. Compared with Embodiment 1, the difference is that the concentrations of each component in the electrolyte are as follows: the volume ratio of cyclic sulfite is 45% (ethylene sulfite), the volume ratio of chain sulfite is 45% (dibutyl sulfite), the volume ratio of film-forming additive is 10% (ethylene fluorocarbonate), and the concentration of electrolyte sodium salt is 1 mol / L (sodium hexafluorophosphate).
[0045] The electrolyte preparation process was carried out in an argon-filled glove box (O2 < 0.1 PPM, H2O < 0.1 PPM). The sodium electrolyte salt was dissolved in the solvent of the above proportions, and the mixture was slowly stirred at room temperature for 10 hours to obtain the sodium metal battery electrolyte of Example 3. The cycle performance of this electrolyte is weaker than that of Example 1.
[0046] Example 4:
[0047] This embodiment discloses a sodium metal battery electrolyte. Compared with Example 1, the difference is that the concentrations of each component in the electrolyte are as follows: cyclic sulfite volume ratio is 45% (propylene sulfite), chain sulfite volume ratio is 45% (dimethyl sulfite), film-forming additive volume ratio is 10% (ethylene fluorocarbonate), and electrolyte sodium salt concentration is 1 mol / L (sodium hexafluorophosphate).
[0048] The electrolyte preparation process was carried out in an argon-filled glove box (O2 < 0.1 PPM, H2O < 0.1 PPM). The sodium electrolyte salt was dissolved in the solvent of the above proportions, and the mixture was slowly stirred at room temperature for 10 hours to obtain the sodium metal battery electrolyte of Example 4. The cycle performance of this electrolyte is weaker than that of Example 1.
[0049] Example 5:
[0050] This embodiment discloses a sodium metal battery electrolyte. Compared with Example 1, the difference is that the concentrations of each component in the electrolyte are as follows: cyclic sulfite volume ratio is 45% (propylene sulfite), chain sulfite volume ratio is 45% (diethyl sulfite), film-forming additive volume ratio is 10% (ethylene fluorocarbonate), and electrolyte sodium salt concentration is 1 mol / L (sodium hexafluorophosphate).
[0051] The electrolyte preparation process was carried out in an argon-filled glove box (O2 < 0.1 PPM, H2O < 0.1 PPM). The sodium electrolyte salt was dissolved in the solvent of the above proportion, and the mixture was slowly stirred at room temperature for 10 hours to obtain the sodium metal battery electrolyte of Example 5. The cycle performance of this electrolyte is weaker than that of Example 1.
[0052] Example 6:
[0053] This embodiment discloses a sodium metal battery electrolyte. Compared with Example 1, the difference is that the concentrations of each component in the electrolyte are as follows: cyclic sulfite volume ratio is 45% (propylene sulfite), chain sulfite volume ratio is 45% (dibutyl sulfite), film-forming additive volume ratio is 10% (ethylene fluorocarbonate), and electrolyte sodium salt concentration is 1 mol / L (sodium hexafluorophosphate).
[0054] The electrolyte preparation process was carried out in an argon-filled glove box (O2 < 0.1 PPM, H2O < 0.1 PPM). The sodium electrolyte salt was dissolved in the solvent of the above proportion, and the mixture was slowly stirred at room temperature for 10 hours to obtain the sodium metal battery electrolyte of Example 6. The cycle performance of this electrolyte is weaker than that of Example 1.
[0055] Example 7:
[0056] This embodiment discloses a sodium metal battery electrolyte, which differs from Embodiment 1 in that the concentrations of each component in this electrolyte are as follows:
[0057] The volume ratio of cyclic sulfites is 45% (4-methyl vinyl sulfite), the volume ratio of chain sulfites is 45% (dimethyl sulfite), the volume ratio of film-forming additives is 10% (fluoroethylene carbonate), and the concentration of electrolyte sodium salt is 1 mol / L (sodium hexafluorophosphate).
[0058] The electrolyte preparation process was carried out in an argon-filled glove box (O2 < 0.1 PPM, H2O < 0.1 PPM). The sodium electrolyte salt was dissolved in the solvent of the above proportion, and the mixture was slowly stirred at room temperature for 10 hours to obtain the sodium metal battery electrolyte of Example 7. The cycle performance of this electrolyte is weaker than that of Example 1.
[0059] Example 8:
[0060] This embodiment discloses a sodium metal battery electrolyte, which differs from Embodiment 1 in that the concentrations of each component in this electrolyte are as follows:
[0061] The volume ratio of cyclic sulfites is 45% (4-methyl vinyl sulfite), the volume ratio of chain sulfites is 45% (diethyl sulfite), the volume ratio of film-forming additives is 10% (ethylene fluorocarbonate), and the concentration of electrolyte sodium salt is 1 mol / L (sodium hexafluorophosphate).
[0062] The electrolyte preparation process was carried out in an argon-filled glove box (O2 < 0.1 PPM, H2O < 0.1 PPM). The sodium electrolyte salt was dissolved in the solvent of the above proportion, and the mixture was slowly stirred at room temperature for 10 hours to obtain the sodium metal battery electrolyte of Example 8. The cycle performance of this electrolyte is weaker than that of Example 1.
[0063] Example 9:
[0064] This embodiment discloses a sodium metal battery electrolyte, which differs from Embodiment 1 in that the concentrations of each component in this electrolyte are as follows:
[0065] The volume ratio of cyclic sulfites is 45% (4-methyl vinyl sulfite), the volume ratio of chain sulfites is 45% (dibutyl sulfite), the volume ratio of film-forming additives is 10% (fluoroethylene carbonate), and the concentration of electrolyte sodium salt is 1 mol / L (sodium hexafluorophosphate).
[0066] The electrolyte preparation process was carried out in an argon-filled glove box (O2 < 0.1 PPM, H2O < 0.1 PPM). The sodium electrolyte salt was dissolved in the solvent of the above proportion, and the mixture was slowly stirred at room temperature for 10 hours to obtain the sodium metal battery electrolyte of Example 9. The cycle performance of this electrolyte is weaker than that of Example 1.
[0067] Example 10:
[0068] This embodiment discloses a sodium metal battery electrolyte, which differs from Embodiment 1 in that the concentrations of each component in this electrolyte are as follows:
[0069] The volume ratio of cyclic sulfites is 45% (ethylene sulfite), the volume ratio of chain sulfites is 45% (diethyl sulfite), the volume ratio of film-forming additives is 10% (ethylene fluorocarbonate), and the concentration of electrolyte sodium salt is 1 mol / L (sodium perchlorate).
[0070] The electrolyte preparation process was carried out in an argon-filled glove box (O2 < 0.1 PPM, H2O < 0.1 PPM). The sodium electrolyte salt was dissolved in the solvent of the above proportion, and the mixture was slowly stirred at room temperature for 10 hours to obtain the sodium metal battery electrolyte of Example 10. The cycle performance of this electrolyte is weaker than that of Example 1.
[0071] Example 11:
[0072] This embodiment discloses a sodium metal battery electrolyte, which differs from Embodiment 1 in that the concentrations of each component in this electrolyte are as follows:
[0073] The volume ratio of cyclic sulfites is 45% (ethylene sulfite), the volume ratio of chain sulfites is 45% (diethyl sulfite), the volume ratio of film-forming additives is 10% (ethylene fluorocarbonate), and the concentration of electrolyte sodium salt is 1 mol / L (sodium bis(fluorosulfonyl)imide).
[0074] The electrolyte preparation process was carried out in an argon-filled glove box (O2 < 0.1 PPM, H2O < 0.1 PPM). The sodium electrolyte salt was dissolved in the solvent of the above proportion, and the mixture was slowly stirred at room temperature for 10 hours to obtain the sodium metal battery electrolyte of Example 11. The cycle performance of this electrolyte is weaker than that of Example 1.
[0075] Example 12:
[0076] This embodiment discloses a sodium metal battery electrolyte, which differs from Embodiment 1 in that the concentrations of each component in this electrolyte are as follows:
[0077] The volume ratio of cyclic sulfites is 45% (ethylene sulfite), the volume ratio of chain sulfites is 45% (diethyl sulfite), the volume ratio of film-forming additives is 10% (ethylene fluorocarbonate), and the concentration of electrolyte sodium salt is 1 mol / L (sodium bis(trifluoromethylsulfonyl)imide).
[0078] The electrolyte preparation process was carried out in an argon-filled glove box (O2 < 0.1 PPM, H2O < 0.1 PPM). The sodium electrolyte salt was dissolved in the solvent of the above proportions, and the mixture was slowly stirred at room temperature for 10 hours to obtain the sodium metal battery electrolyte of Example 12. The cycle performance of this electrolyte is weaker than that of Example 1.
[0079] Example 13:
[0080] This embodiment discloses a sodium metal battery electrolyte, which differs from Embodiment 1 in that the concentrations of each component in this electrolyte are as follows:
[0081] The volume ratio of cyclic sulfites is 45% (ethylene sulfite), the volume ratio of chain sulfites is 45% (diethyl sulfite), the volume ratio of film-forming additives is 10% (ethylene fluorocarbonate), and the concentration of electrolyte sodium salt is 1 mol / L (sodium trifluoromethanesulfonate).
[0082] The electrolyte preparation process was carried out in an argon-filled glove box (O2 < 0.1 PPM, H2O < 0.1 PPM). The sodium electrolyte salt was dissolved in the solvent of the above proportion, and the mixture was slowly stirred at room temperature for 10 hours to obtain the sodium metal battery electrolyte of Example 13. The cycle performance of this electrolyte is weaker than that of Example 1.
[0083] Example 14:
[0084] This embodiment discloses a sodium metal battery electrolyte, which differs from Embodiment 1 in that the concentrations of each component in this electrolyte are as follows:
[0085] The volume ratio of cyclic sulfites is 45% (ethylene sulfite), the volume ratio of chain sulfites is 45% (diethyl sulfite), the volume ratio of film-forming additives is 10% (ethylene carbonate), and the concentration of electrolyte sodium salt is 1 mol / L (sodium hexafluorophosphate).
[0086] The electrolyte preparation process was carried out in an argon-filled glove box (O2 < 0.1 PPM, H2O < 0.1 PPM). The sodium electrolyte salt was dissolved in the solvent of the above proportion, and the mixture was slowly stirred at room temperature for 10 hours to obtain the sodium metal battery electrolyte of Example 14. The cycle performance of this electrolyte is weaker than that of Example 1.
[0087] Example 15:
[0088] This embodiment discloses a sodium metal battery electrolyte, which differs from Embodiment 1 in that the concentrations of each component in this electrolyte are as follows:
[0089] The volume ratio of cyclic sulfites was 45% (ethylene sulfite), the volume ratio of chain sulfites was 45% (diethyl sulfite), the volume ratio of film-forming additives was 10% (1,3-propanesulfonyl lactone), and the concentration of electrolyte sodium salt was 1 mol / L (sodium hexafluorophosphate).
[0090] The electrolyte preparation process was carried out in an argon-filled glove box (O2 < 0.1 PPM, H2O < 0.1 PPM). The sodium electrolyte salt was dissolved in the solvent of the above proportions, and the mixture was slowly stirred at room temperature for 10 hours to obtain the sodium metal battery electrolyte of Example 15. The cycle performance of this electrolyte is weaker than that of Example 1.
[0091] Example 16:
[0092] This embodiment discloses a sodium metal battery electrolyte, which differs from Embodiment 1 in that the concentrations of each component in this electrolyte are as follows:
[0093] The volume ratio of cyclic sulfites is 45% (ethylene sulfite / propylene sulfite is 1:1), the volume ratio of chain sulfites is 45% (diethyl sulfite), the volume ratio of film-forming additives is 10% (ethylene fluorocarbonate), and the concentration of electrolyte sodium salt is 1 mol / L (sodium hexafluorophosphate).
[0094] The electrolyte preparation process was carried out in an argon-filled glove box (O2 < 0.1 PPM, H2O < 0.1 PPM). The sodium electrolyte salt was dissolved in the solvent of the above proportion, and the mixture was slowly stirred at room temperature for 10 hours to obtain the sodium metal battery electrolyte of Example 16. The cycle performance of this electrolyte is weaker than that of Example 1.
[0095] Example 17:
[0096] This embodiment discloses a sodium metal battery electrolyte, which differs from Embodiment 1 in that the concentrations of each component in this electrolyte are as follows:
[0097] The volume ratio of cyclic sulfites is 45% (ethylene sulfite / propylene sulfite / 4-methylethylene sulfite in a 1:1:1 ratio), the volume ratio of chain sulfites is 45% (diethyl sulfite), the volume ratio of film-forming additives is 10% (ethylene fluorocarbonate), and the concentration of electrolyte sodium salt is 1 mol / L (sodium hexafluorophosphate).
[0098] The electrolyte preparation process was carried out in an argon-filled glove box (O2 < 0.1 PPM, H2O < 0.1 PPM). The sodium electrolyte salt was dissolved in the solvent of the above proportion, and the mixture was slowly stirred at room temperature for 10 hours to obtain the sodium metal battery electrolyte of Example 17. The cycle performance of this electrolyte is weaker than that of Example 1.
[0099] Example 18:
[0100] This embodiment discloses a sodium metal battery electrolyte, which differs from Embodiment 1 in that the concentrations of each component in this electrolyte are as follows:
[0101] The volume ratio of cyclic sulfites is 45% (ethylene sulfite / propylene sulfite / 4-methylethylene sulfite in a 1:1:1 ratio), the volume ratio of chain sulfites is 45% (dimethyl sulfite / diethyl sulfite in a 1:1 ratio), the volume ratio of film-forming additives is 10% (ethylene fluorocarbonate), and the concentration of electrolyte sodium salt is 1 mol / L (sodium hexafluorophosphate).
[0102] The electrolyte preparation process was carried out in an argon-filled glove box (O2 < 0.1 PPM, H2O < 0.1 PPM). The sodium electrolyte salt was dissolved in the solvent of the above proportion, and the mixture was slowly stirred at room temperature for 10 hours to obtain the sodium metal battery electrolyte of Example 18. The cycle performance of this electrolyte is weaker than that of Example 1.
[0103] Example 19:
[0104] This embodiment discloses a sodium metal battery electrolyte, which differs from Embodiment 1 in that the concentrations of each component in this electrolyte are as follows:
[0105] The volume ratio of cyclic sulfites is 45% (ethylene sulfite / propylene sulfite / 4-methylethylene sulfite in a 1:1:1 ratio), the volume ratio of chain sulfites is 45% (dimethyl sulfite / diethyl sulfite / dibutyl sulfite in a 1:1:1 ratio), the volume ratio of film-forming additive is 10% (ethylene fluorocarbonate), and the concentration of electrolyte sodium salt is 1 mol / L (sodium hexafluorophosphate).
[0106] The electrolyte preparation process was carried out in an argon-filled glove box (O2 < 0.1 PPM, H2O < 0.1 PPM). The sodium electrolyte salt was dissolved in the solvent of the above proportions, and the mixture was slowly stirred at room temperature for 10 hours to obtain the sodium metal battery electrolyte of Example 19. The cycle performance of this electrolyte is weaker than that of Example 1.
[0107] Example 20:
[0108] This embodiment discloses a sodium metal battery electrolyte, which differs from Embodiment 1 in that the concentrations of each component in this electrolyte are as follows:
[0109] The volume ratio of cyclic sulfites is 45% (ethylene sulfite / propylene sulfite / 4-methylethylene sulfite in a 1:1:1 ratio), the volume ratio of chain sulfites is 45% (dimethyl sulfite / diethyl sulfite / dibutyl sulfite in a 1:1:1 ratio), the volume ratio of film-forming additives is 10% (fluoroethylene carbonate / ethylene carbonate in a 1:1 ratio), and the concentration of electrolyte sodium salt is 1 mol / L (sodium hexafluorophosphate).
[0110] The electrolyte preparation process was carried out in an argon-filled glove box (O2 < 0.1 PPM, H2O < 0.1 PPM). The sodium electrolyte salt was dissolved in the solvent of the above proportion, and the mixture was slowly stirred at room temperature for 10 hours to obtain the sodium metal battery electrolyte of Example 20. The cycle performance of this electrolyte is weaker than that of Example 1.
[0111] Example 21:
[0112] This embodiment discloses a sodium metal battery electrolyte, which differs from Embodiment 1 in that the concentrations of each component in this electrolyte are as follows:
[0113] The volume ratio of cyclic sulfites is 45% (ethylene sulfite / propylene sulfite / 4-methylethylene sulfite in a 1:1:1 ratio), the volume ratio of chain sulfites is 45% (dimethyl sulfite / diethyl sulfite / dibutyl sulfite in a 1:1:1 ratio), the volume ratio of film-forming additives is 10% (fluoroethylene carbonate / ethylene carbonate / 1,3-propanesulfonyl lactone in a 1:1:1 ratio), and the concentration of electrolyte sodium salt is 1 mol / L (sodium hexafluorophosphate).
[0114] The electrolyte preparation process was carried out in an argon-filled glove box (O2 < 0.1 PPM, H2O < 0.1 PPM). The sodium electrolyte salt was dissolved in the solvent of the above proportion, and the mixture was slowly stirred at room temperature for 10 hours to obtain the sodium metal battery electrolyte of Example 21. The cycle performance of this electrolyte is weaker than that of Example 1.
[0115] Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.
Claims
1. A sodium metal battery electrolyte, characterized in that, include: Organic solvents, sodium electrolyte salts, and film-forming additives, The organic solvent is a sulfite containing a –SO3 group, and the volume of the sulfite accounts for 90-98% of the electrolyte volume of the sodium metal battery.
2. The sodium metal battery electrolyte according to claim 1, characterized in that: in, The sulfites include cyclic sulfites and chain sulfites. The cyclic sulfite includes at least one selected from vinyl sulfite, propylene sulfite, and 4-methylvinyl sulfite, and the volume of the cyclic sulfite accounts for 30% to 80% of the volume of the sodium-ion battery electrolyte. The chain sulfite includes at least one of dimethyl sulfite, diethyl sulfite, and dipropyl sulfite, and the volume of the chain sulfite accounts for 10% to 60% of the volume of the sodium metal battery electrolyte.
3. The sodium metal battery electrolyte according to claim 1, characterized in that: in, The film-forming additive is at least one of fluoroethylene carbonate, vinylene carbonate, and 1,3-propanesulfonyl lactone, and the volume of the film-forming additive accounts for 2 to 10% of the volume of the sodium metal battery electrolyte.
4. The sodium metal battery electrolyte according to claim 1, characterized in that: in, The electrolyte sodium salt is one or more of sodium perchlorate, sodium hexafluorophosphate, sodium bis(fluorosulfonyl)imide, sodium bis(trifluoromethylsulfonyl)imide, and sodium trifluoromethylsulfonate.
5. The sodium metal battery electrolyte according to claim 4, characterized in that: in, The concentration of the sodium electrolyte salt in the sodium metal battery electrolyte is 0.5–1.5 mol / L.
6. The sodium metal battery electrolyte according to claim 1, characterized in that: in, The density of the sodium metal battery electrolyte is 1.0–1.5 g / cm³. 3 Its electrical conductivity is 6–12 mS / cm.
7. A method for preparing a sodium metal battery electrolyte according to any one of claims 1-6, characterized in that, The preparation method includes: The sodium electrolyte is obtained by dissolving the sodium salt in the organic solvent and then adding it to a mixed solvent prepared by the film-forming additive.
8. The use of a sodium metal battery electrolyte as described in any one of claims 1-6 in the preparation of a sodium metal battery.
9. A sodium metal battery, characterized in that, include: The sodium metal battery electrolyte, current collector, and sodium sheet according to any one of claims 1-6.