A high-rate sodium ion battery electrolyte and preparation method thereof

Abstract

The present invention discloses a high-rate sodium ion battery electrolyte and a preparation method thereof, belonging to the technical field of sodium ion batteries. The raw materials for preparing the sodium ion battery electrolyte include sodium salt, organic solvent, and additives; the prepared ionic liquid is used as an additive, and the ionic liquid additive is added to the electrolyte and applied to the sodium ion battery, which is beneficial to promote the migration and transmission of sodium ions, promote the formation of a dense SE I film, can show better performance at high rate discharge, reduce internal resistance and irreversible capacity loss, thereby improving the stability and life of the battery. The design of this electrolyte has broad application prospects in lithium ion batteries, especially in applications requiring high performance and high rate discharge.

Description

Technical Field

[0001] The invention belongs to the technical field of sodium ion batteries, and in particular relates to a high-rate sodium ion battery electrolyte and a preparation method thereof. Background Art

[0002] As one of the important components of the battery, the electrolyte is the medium of the electrochemical reaction. The electrolyte reacts on the electrode surface and affects the specific capacity, cycle stability and cycle life of the battery. During the cycle, a passivation layer covering the surface of the electrode material is formed at the interface between the electrolyte and the electrode, namely the solid electrolyte interface film (SE I). SE I has an impact on the energy density, cycle stability, rate performance, etc. of the electrode. Therefore, improving the SE I film-forming property of the electrolyte is crucial to improving the rate performance, cycle stability and cycle life of sodium ion batteries. In the electrolyte of sodium ion batteries, the selection and preparation of additives have a direct impact on the performance of the electrolyte. The additives in traditional electrolytes are mostly designed for lithium ion batteries, and the application effect in sodium ion batteries is not ideal. Therefore, developing an electrolyte additive suitable for sodium ion batteries to improve the SEI film-forming property of the electrolyte and improve the rate performance, cycle stability and cycle life of sodium ion batteries has become a research hotspot in the current field of sodium ion battery technology. Summary of the invention

[0003] The object of the present invention is to provide a high-rate sodium ion battery electrolyte and a preparation method thereof, so as to solve the problems of poor rate performance and cycle stability of sodium ion batteries.

[0004] The purpose of the present invention can be achieved through the following technical solutions:

[0005] A high-rate sodium ion battery electrolyte, wherein the raw materials for preparing the sodium ion battery electrolyte include the following raw materials in parts by weight:

[0006] Sodium salt 12-18 parts by weight

[0007] Organic solvent 75-85 parts by mass

[0008] Additives 4-6 parts by mass;

[0009] The preparation of the additive comprises the following steps:

[0010] S1, aminoethanethiol hydrochloride (purchased from Baoding Jiufu Customization Co., Ltd.), 4-bromo-1-butene, anhydrous ethanol, deionized water, and sodium hydroxide solution were mixed, stirred at room temperature for 7-9 hours, and the solvent was removed by rotary evaporation at 105° C. in a nitrogen atmosphere to obtain material A;

[0011] S2, taking the material A, 3-chloro-5-trifluoromethylpyridine-2-carboxylic acid (purchased from (Alpha) Zhengzhou Alpha Chemical Co., Ltd.), dichloroethane, triethylamine, phosphorus oxychloride, mixing, stirring at room temperature for 8-10 hours, washing, and drying to obtain material B;

[0012] S3, taking the material B, cyanamide, (diacetoxyiodo)benzene, and acetonitrile, mixing, stirring for 7-10 hours in an ice-water bath, then adding m-chloroperbenzoic acid, sodium carbonate, and anhydrous ethanol, continuing to stir for 7-10 hours, filtering, washing the solid phase with water, and drying to obtain material C;

[0013] S4, taking the material C, 1-methylpiperidine and ethyl acetate, mixing, stirring in a water bath at 55-65° C. for 7-9 hours, filtering, and vacuum drying the solid phase for 20-30 hours to obtain material D;

[0014] S5. Take the material D, sodium bis(fluorosulfonyl)imide and deionized water, mix them, stir them at room temperature for 12-16 hours, extract them with dichloromethane and wash them 4-5 times until no chloride ions are detected in the dichloromethane phase, remove dichloromethane by rotary evaporation, and vacuum dry them to obtain the additive.

[0015] As a preferred technical solution of the present invention, in step S1, the dosage ratio of aminoethanethiol hydrochloride, 4-bromo-1-butene, anhydrous ethanol, deionized water, and sodium hydroxide solution is 10-15g: 20-22g: 60-80mL: 20-30mL: 4-6mL; the concentration of the sodium hydroxide solution is 1-2mol / L.

[0016] As a preferred technical solution of the present invention, in step S2, the mass ratio of material A, 3-chloro-5-trifluoromethylpyridine-2-carboxylic acid, dichloroethane, triethylamine, and phosphorus oxychloride is 6-8:7-9:150:0.3-0.4:0.5-0.6.

[0017] As a preferred technical solution of the present invention, in step S3, the mass ratio of material B, cyanamide, (diacetoxyiodo)benzene, acetonitrile, m-chloroperbenzoic acid, sodium carbonate, and anhydrous ethanol is 5-6:5.2-6.4:0.3-0.5:80-100:0.2-0.3:0.5-0.6:80-100.

[0018] As a preferred technical solution of the present invention, in step S4, the mass ratio of the material C, 1-methylpiperidine and ethyl acetate is 4-6:5-7:80-100.

[0019] As a preferred technical solution of the present invention, in step S5, the mass ratio of the material D, sodium bis(fluorosulfonyl)imide and deionized water is 3-5:3-5:50.

[0020] As a preferred technical solution of the present invention, the sodium salt is composed of sodium hexafluorophosphate, sodium perchlorate and sodium tetrafluoroborate in a mass ratio of 3:1.8:0.2.

[0021] As a preferred technical solution of the present invention, the organic solvent is composed of ethylene carbonate, dimethyl carbonate and acetonitrile in a volume ratio of 1:1:0.4.

[0022] The above-mentioned method for preparing the high-rate sodium ion battery electrolyte comprises mixing the raw materials for preparing the sodium ion battery electrolyte in proportion.

[0023] Beneficial effects of the present invention:

[0024] The high-rate sodium ion battery electrolyte and preparation method disclosed in the present invention are applied to sodium ion batteries by adding ionic liquid additives to the electrolyte, which is beneficial to promote the migration and transmission of sodium ions, promote the formation of a dense SE I film, and can show better performance during high-rate discharge, reduce internal resistance and irreversible capacity loss, thereby improving the stability and life of the battery. The design of this electrolyte has broad application prospects in lithium ion batteries, especially in applications requiring high performance and high-rate discharge. DETAILED DESCRIPTION

[0025] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in combination with the embodiments.

[0026] Example 1

[0027] In a glove box filled with argon, 12 parts by mass of sodium salt, 75 parts by mass of organic solvent and 4 parts by mass of additive are mixed to obtain a sodium ion battery electrolyte; wherein the sodium salt is composed of sodium hexafluorophosphate, sodium perchlorate and sodium tetrafluoroborate in a mass ratio of 3:1.8:0.2; the organic solvent is composed of ethylene carbonate, dimethyl carbonate and acetonitrile in a volume ratio of 1:1:0.4;

[0028] The structural formula of the additive is shown below:

[0029]

[0030] The preparation of the additive comprises the following steps:

[0031] S1. Mix aminoethanethiol hydrochloride, 4-bromo-1-butene, anhydrous ethanol, deionized water and sodium hydroxide solution, stir at room temperature for 7 hours, and remove the solvent by rotary evaporation at 105°C in a nitrogen atmosphere to obtain material A; the dosage ratio of aminoethanethiol hydrochloride, 4-bromo-1-butene, anhydrous ethanol, deionized water and sodium hydroxide solution is 10g:20g:60mL:20mL:4mL; the concentration of the sodium hydroxide solution is 1mol / L;

[0032] S2, take the material A, 3-chloro-5-trifluoromethylpyridine-2-carboxylic acid, dichloroethane, triethylamine, phosphorus oxychloride, mix, stir at room temperature for 8 hours, wash, dry, and obtain material B; the mass ratio of the material A, 3-chloro-5-trifluoromethylpyridine-2-carboxylic acid, dichloroethane, triethylamine, phosphorus oxychloride is 6:7:150:0.3:0.5;

[0033] S3, taking the material B, cyanamide, (diacetoxyiodine) benzene, and acetonitrile, mixing, stirring for 7 hours in an ice-water bath, then adding m-chloroperbenzoic acid, sodium carbonate, and anhydrous ethanol, continuing to stir for 7 hours, filtering, washing the solid phase with water, and drying to obtain material C; the mass ratio of the material B, cyanamide, (diacetoxyiodine) benzene, acetonitrile, m-chloroperbenzoic acid, sodium carbonate, and anhydrous ethanol is 5:5.2:0.3:80:0.2:0.5:80;

[0034] S4, taking the material C, 1-methylpiperidine, and ethyl acetate, mixing, stirring in a water bath at 55°C for 7 hours, filtering, and vacuum drying the solid phase for 20 hours to obtain material D; the mass ratio of the material C, 1-methylpiperidine, and ethyl acetate is 4:5:80;

[0035] S5. Take the material D, sodium bis(fluorosulfonyl)imide and deionized water, mix them, stir at room temperature for 12 hours, extract with dichloromethane and wash 4 times until no chloride ions are detected in the dichloromethane phase, remove dichloromethane by rotary evaporation, and vacuum dry to obtain the additive; the mass ratio of the material D, sodium bis(fluorosulfonyl)imide and deionized water is 3:3:50.

[0036] Example 2

[0037] In a glove box filled with argon, 15 parts by mass of sodium salt, 80 parts by mass of organic solvent and 5 parts by mass of additive are mixed to obtain a sodium ion battery electrolyte; wherein the sodium salt is composed of sodium hexafluorophosphate, sodium perchlorate and sodium tetrafluoroborate in a mass ratio of 3:1.8:0.2; the organic solvent is composed of ethylene carbonate, dimethyl carbonate and acetonitrile in a volume ratio of 1:1:0.4;

[0038] The preparation of the additive comprises the following steps:

[0039] S1. Mix aminoethanethiol hydrochloride, 4-bromo-1-butene, anhydrous ethanol, deionized water and sodium hydroxide solution, stir at room temperature for 8 hours, and remove the solvent by rotary evaporation at 105°C in a nitrogen atmosphere to obtain material A; the dosage ratio of aminoethanethiol hydrochloride, 4-bromo-1-butene, anhydrous ethanol, deionized water and sodium hydroxide solution is 13g:21g:70mL:25mL:5mL; the concentration of the sodium hydroxide solution is 1.5mol / L;

[0040] S2, take the material A, 3-chloro-5-trifluoromethylpyridine-2-carboxylic acid, dichloroethane, triethylamine, phosphorus oxychloride, mix, stir at room temperature for 9 hours, wash, dry, and obtain material B; the mass ratio of the material A, 3-chloro-5-trifluoromethylpyridine-2-carboxylic acid, dichloroethane, triethylamine, phosphorus oxychloride is 7:8:150:0.35:0.55;

[0041] S3, taking the material B, cyanamide, (diacetoxyiodine) benzene, and acetonitrile, mixing, stirring for 8 hours in an ice-water bath, then adding m-chloroperbenzoic acid, sodium carbonate, and anhydrous ethanol, continuing to stir for 8 hours, filtering, washing the solid phase with water, and drying to obtain material C; the mass ratio of the material B, cyanamide, (diacetoxyiodine) benzene, acetonitrile, m-chloroperbenzoic acid, sodium carbonate, and anhydrous ethanol is 5.5:5.8:0.4:90:0.25:0.55:90;

[0042] S4, taking the material C, 1-methylpiperidine, and ethyl acetate, mixing, stirring in a water bath at 60°C for 8h, filtering, and vacuum drying the solid phase for 25h to obtain material D; the mass ratio of the material C, 1-methylpiperidine, and ethyl acetate is 5:6:90;

[0043] S5. Take the material D, sodium bis(fluorosulfonyl)imide and deionized water, mix them, stir them at room temperature for 14 hours, extract them with dichloromethane and wash them 5 times until no chloride ions are detected in the dichloromethane phase, remove dichloromethane by rotary evaporation, and vacuum dry them to obtain the additive; the mass ratio of the material D, sodium bis(fluorosulfonyl)imide and deionized water is 4:4:50.

[0044] Example 3

[0045] In a glove box filled with argon, 18 parts by mass of sodium salt, 85 parts by mass of organic solvent and 6 parts by mass of additive are mixed to obtain a sodium ion battery electrolyte; wherein the sodium salt is composed of sodium hexafluorophosphate, sodium perchlorate and sodium tetrafluoroborate in a mass ratio of 3:1.8:0.2; the organic solvent is composed of ethylene carbonate, dimethyl carbonate and acetonitrile in a volume ratio of 1:1:0.4;

[0046] The preparation of the additive comprises the following steps:

[0047] S1, take aminoethanethiol hydrochloride, 4-bromo-1-butene, anhydrous ethanol, deionized water, and sodium hydroxide solution, mix them, stir them at room temperature for 9 hours, and remove the solvent by rotary evaporation at 105°C in a nitrogen atmosphere to obtain material A; the dosage ratio of aminoethanethiol hydrochloride, 4-bromo-1-butene, anhydrous ethanol, deionized water, and sodium hydroxide solution is 15g:22g:80mL:30mL:6mL; the concentration of the sodium hydroxide solution is 2mol / L;

[0048] S2, take the material A, 3-chloro-5-trifluoromethylpyridine-2-carboxylic acid, dichloroethane, triethylamine, phosphorus oxychloride, mix, stir at room temperature for 10 hours, wash, dry, and obtain material B; the mass ratio of the material A, 3-chloro-5-trifluoromethylpyridine-2-carboxylic acid, dichloroethane, triethylamine, phosphorus oxychloride is 8:9:150:0.4:0.6;

[0049] S3, take the material B, cyanamide, (diacetoxyiodine) benzene, acetonitrile, mix, stir for 10 hours in an ice-water bath, then add m-chloroperbenzoic acid, sodium carbonate, anhydrous ethanol, continue stirring for 10 hours, filter, wash the solid phase with water, and dry to obtain material C; the mass ratio of the material B, cyanamide, (diacetoxyiodine) benzene, acetonitrile, m-chloroperbenzoic acid, sodium carbonate, and anhydrous ethanol is 6:5.6.4:0.5:100:0.3:0.6:100;

[0050] S4, taking the material C, 1-methylpiperidine, and ethyl acetate, mixing, stirring in a water bath at 65°C for 9 hours, filtering, and vacuum drying the solid phase for 30 hours to obtain material D; the mass ratio of the material C, 1-methylpiperidine, and ethyl acetate is 6:7:100;

[0051] S5. Take the material D, sodium bis(fluorosulfonyl)imide and deionized water, mix them, stir them at room temperature for 16 hours, extract them with dichloromethane and wash them 5 times until no chloride ions are detected in the dichloromethane phase, remove dichloromethane by rotary evaporation, and vacuum dry them to obtain the additive; the mass ratio of the material D, sodium bis(fluorosulfonyl)imide and deionized water is 5:5:50.

[0052] Comparative Example 1

[0053] The difference from Example 1 is that the added amount of the additive is 0 parts by mass.

[0054] Comparative Example 2

[0055] The difference from Example 1 is that the added amount of the additive is 1 part by mass.

[0056] Comparative Example 3

[0057] The difference from Example 1 is that the added amount of the additive is 2 parts by mass.

[0058] Comparative Example 4

[0059] The difference from Example 1 is that the added amount of the additive is 3 parts by mass.

[0060] Comparative Example 5

[0061] The difference from Example 1 is that the added amount of the additive is 7 parts by mass.

[0062] Comparative Example 6

[0063] The difference from Example 1 is that the added amount of the additive is 8 parts by mass.

[0064] Comparative Example 7

[0065] The difference from Example 1 is that the preparation of the additive comprises the following steps:

[0066] S1. Mix aminoethanethiol hydrochloride, 4-bromo-1-butene, anhydrous ethanol, deionized water and sodium hydroxide solution, stir at room temperature for 7 hours, and remove the solvent by rotary evaporation at 105°C in a nitrogen atmosphere to obtain material A; the dosage ratio of aminoethanethiol hydrochloride, 4-bromo-1-butene, anhydrous ethanol, deionized water and sodium hydroxide solution is 10g:20g:60mL:20mL:4mL; the concentration of the sodium hydroxide solution is 1mol / L;

[0067] S2, take the material A, 3-chloro-5-trifluoromethylpyridine-2-carboxylic acid, dichloroethane, triethylamine, phosphorus oxychloride, mix, stir at room temperature for 8 hours, wash, dry, and obtain material B; the mass ratio of the material A, 3-chloro-5-trifluoromethylpyridine-2-carboxylic acid, dichloroethane, triethylamine, phosphorus oxychloride is 6:7:150:0.3:0.5;

[0068] S3, taking the material B, cyanamide, (diacetoxyiodine) benzene, and acetonitrile, mixing, stirring for 7 hours in an ice-water bath, then adding m-chloroperbenzoic acid, sodium carbonate, and anhydrous ethanol, continuing to stir for 7 hours, filtering, washing the solid phase with water, and drying to obtain material C; the mass ratio of the material B, cyanamide, (diacetoxyiodine) benzene, acetonitrile, m-chloroperbenzoic acid, sodium carbonate, and anhydrous ethanol is 5:5.2:0.3:80:0.2:0.5:80;

[0069] S4. Take the material C, sodium bis(fluorosulfonyl)imide and deionized water, mix them, stir at room temperature for 12 hours, extract with dichloromethane and wash 4 times until no chloride ions are detected in the dichloromethane phase, remove dichloromethane by rotary evaporation, and vacuum dry to obtain the additive; the mass ratio of the material C, sodium bis(fluorosulfonyl)imide and deionized water is 3:3:50.

[0070] Comparative Example 8

[0071] The difference from Example 1 is that the preparation of the additive comprises the following steps:

[0072] S1. Mix aminoethanethiol hydrochloride, 4-bromo-1-butene, anhydrous ethanol, deionized water and sodium hydroxide solution, stir at room temperature for 7 hours, and remove the solvent by rotary evaporation at 105°C in a nitrogen atmosphere to obtain material A; the dosage ratio of aminoethanethiol hydrochloride, 4-bromo-1-butene, anhydrous ethanol, deionized water and sodium hydroxide solution is 10g:20g:60mL:20mL:4mL; the concentration of the sodium hydroxide solution is 1mol / L;

[0073] S2, take the material A, 3-chloro-5-trifluoromethylpyridine-2-carboxylic acid, dichloroethane, triethylamine, phosphorus oxychloride, mix, stir at room temperature for 8 hours, wash, dry, and obtain material B; the mass ratio of the material A, 3-chloro-5-trifluoromethylpyridine-2-carboxylic acid, dichloroethane, triethylamine, phosphorus oxychloride is 6:7:150:0.3:0.5;

[0074] S3, taking the material B, cyanamide, (diacetoxyiodine) benzene, and acetonitrile, mixing, stirring for 7 hours in an ice-water bath, then adding m-chloroperbenzoic acid, sodium carbonate, and anhydrous ethanol, continuing to stir for 7 hours, filtering, washing the solid phase with water, and drying to obtain material C; the mass ratio of the material B, cyanamide, (diacetoxyiodine) benzene, acetonitrile, m-chloroperbenzoic acid, sodium carbonate, and anhydrous ethanol is 5:5.2:0.3:80:0.2:0.5:80;

[0075] S4, taking the material C, 1-methylpiperidine, and ethyl acetate, mixing, stirring in a water bath at 55°C for 7 hours, filtering, and vacuum drying the solid phase for 20 hours to obtain material D; the mass ratio of the material C, 1-methylpiperidine, and ethyl acetate is 4:5:80;

[0076] S5. Mix the material D and deionized water, stir at room temperature for 12 hours, and vacuum dry to obtain the additive; the mass ratio of the material D to deionized water is 6:50.

[0077] Performance Testing

[0078] The sodium ion battery electrolytes prepared in the above Examples 1-5 and Comparative Examples 1-8 were used for battery assembly to obtain CR2032 button batteries, and the charge and discharge capacity tests were carried out in sequence: At room temperature, the following performance tests were carried out using the Land CT2001A battery test system:

[0079] The capacity retention rate test was performed at 25°C (1C / 1C 2.0-4.2V) for 1000 cycles.

[0080] Rate discharge test conditions: at 25°C, 1C charge cut-off current 0.02C, 25C discharge, charge cut-off voltage 4.2V, discharge cut-off voltage 2.75V;

[0081] Discharge efficiency calculation method: 25℃, 1C charging to 4.2V, cut-off current 0.02C, charging capacity A, 25℃, 25C discharging to 2.75V, discharging capacity B, discharge efficiency = B / A;

[0082] The test results are shown in Table 1.

[0083] Table 1

[0084]

[0085] As can be seen from Table 1, the electrolytes prepared in Examples 1-3 of the present application can be applied to sodium ion batteries to show better performance at high rate discharge, reduce internal resistance and irreversible capacity loss, and thus improve battery stability and life. This electrolyte design has broad application prospects in lithium ion batteries, especially in applications requiring high performance and high rate discharge.

[0086] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A high-rate sodium ion battery electrolyte, characterized in that: The raw materials for preparing the sodium ion battery electrolyte include the following raw materials in parts by weight: Sodium salt 12-18 parts by weight Organic solvent 75-85 parts by mass Additives 4-6 parts by weight; The structural formula of the additive is shown below: The preparation of the additive comprises the following steps: S1, aminoethanethiol hydrochloride, 4-bromo-1-butene, anhydrous ethanol, deionized water, and sodium hydroxide solution were mixed, stirred at room temperature for 7-9 hours, and the solvent was removed by rotary evaporation at 105° C. in a nitrogen atmosphere to obtain material A; S2, taking the material A, 3-chloro-5-trifluoromethylpyridine-2-carboxylic acid, dichloroethane, triethylamine, phosphorus oxychloride, mixing, stirring at room temperature for 8-10 hours, washing, and drying to obtain material B; S3, taking the material B, cyanamide, (diacetoxyiodo)benzene, and acetonitrile, mixing, stirring for 7-10 hours in an ice-water bath, then adding m-chloroperbenzoic acid, sodium carbonate, and anhydrous ethanol, continuing to stir for 7-10 hours, filtering, washing the solid phase with water, and drying to obtain material C; S4, taking the material C, 1-methylpiperidine and ethyl acetate, mixing, stirring in a water bath at 55-65° C. for 7-9 hours, filtering, and vacuum drying the solid phase for 20-30 hours to obtain material D; S5. Take the material D, sodium bis(fluorosulfonyl)imide and deionized water, mix them, stir them at room temperature for 12-16 hours, extract them with dichloromethane and wash them 4-5 times until no chloride ions are detected in the dichloromethane phase, remove dichloromethane by rotary evaporation, and vacuum dry them to obtain the additive.

2. A high-rate sodium ion battery electrolyte according to claim 1, characterized in that: In step S1, the dosage ratio of aminoethanethiol hydrochloride, 4-bromo-1-butene, anhydrous ethanol, deionized water, and sodium hydroxide solution is 10-15 g: 20-22 g: 60-80 mL: 20-30 mL: 4-6 mL; the concentration of the sodium hydroxide solution is 1-2 mol / L.

3. A high-rate sodium ion battery electrolyte according to claim 1, characterized in that: In step S2, the mass ratio of material A, 3-chloro-5-trifluoromethylpyridine-2-carboxylic acid, dichloroethane, triethylamine and phosphorus oxychloride is 6-8:7-9:150:0.3-0.4:0.5-0.

6.

4. A high-rate sodium ion battery electrolyte according to claim 1, characterized in that: In step S3, the mass ratio of material B, cyanamide, (diacetoxyiodo)benzene, acetonitrile, m-chloroperbenzoic acid, sodium carbonate and anhydrous ethanol is 5-6:5.2-6.4:0.3-0.5:80-100:0.2-0.3:0.5-0.6:80-100.

5. A high-rate sodium ion battery electrolyte according to claim 1, characterized in that: In step S4, the mass ratio of material C, 1-methylpiperidine and ethyl acetate is 4-6:5-7:80-100.

6. A high-rate sodium ion battery electrolyte according to claim 1, characterized in that: In step S5, the mass ratio of the material D, sodium bis(fluorosulfonyl)imide and deionized water is 3-5:3-5:

50.

7. A high-rate sodium ion battery electrolyte according to claim 1, characterized in that: The sodium salt is composed of sodium hexafluorophosphate, sodium perchlorate and sodium tetrafluoroborate in a mass ratio of 3:1.8:0.

2.

8. A high-rate sodium ion battery electrolyte according to claim 1, characterized in that: The organic solvent is composed of ethylene carbonate, dimethyl carbonate and acetonitrile in a volume ratio of 1:1:0.

4.

9. A method for preparing a high-rate sodium ion battery electrolyte according to any one of claims 1 to 8, characterized in that: The preparation method comprises mixing the raw materials for preparing the sodium ion battery electrolyte in proportion.

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