Production process of sodium-ion battery electrolyte

Abstract

The application provides a production process of a sodium ion battery electrolyte. The production process comprises the following steps: a) dissolving phosphorus pentachloride in a carbonate solvent under a protective atmosphere, then adding ammonium fluoride and performing a solid-phase reaction by heating; then, removing insoluble substances through solid-liquid separation to obtain solution A; b) dispersing a sodium source in a solvent to obtain solution B; c) adding solution B into solution A under a protective atmosphere to perform a reaction, then removing impurities through solid-liquid separation and removing the solvent introduced in step b) to obtain a crude sodium ion battery electrolyte; d) mixing the sodium ion battery electrolyte with an organic solvent to obtain a sodium ion battery electrolyte; the organic solvent is different from the carbonate solvent used in step a); wherein, steps a) and b) are not limited in sequence. The production process can directly prepare a sodium ion battery electrolyte with sodium hexafluorophosphate as a sodium salt, the process is simple and environmentally friendly, and the yield and purity of sodium hexafluorophosphate are relatively high.

Description

Technical Field

[0001] This invention relates to the field of energy materials, and in particular to a production process for sodium-ion battery electrolyte. Background Technology

[0002] In recent years, with the increasing prominence of global warming and the energy crisis, the development of renewable energy sources has become an urgent priority. Currently, among numerous new energy sources, lithium-ion batteries have become a hot topic in our lives due to their high voltage, high energy density, and long lifespan. They are widely used in our studies, daily life, and office work, making them one of the most popular green energy sources. However, lithium resources on Earth are relatively limited. To alleviate resource scarcity, sodium-ion batteries have gradually come into focus. Because sodium resources are abundant and low-cost, and because the working principle of sodium-ion batteries is basically similar to that of lithium-ion batteries, sodium-ion batteries have received widespread attention.

[0003] In existing battery systems, the electrolyte, as an integral part of the battery, plays a crucial role in its electrochemical performance, much like blood in the human body. Currently, the most mature electrolyte system is an ester electrolyte using sodium hexafluorophosphate (NaPF6) as the sodium salt. Due to its excellent overall performance, this system is widely used commercially. Meanwhile, with rapid economic and social development, the demand for batteries from consumer electronics and electric vehicles is constantly increasing, especially for new energy vehicles using power batteries. Therefore, the domestic and international market demand for sodium-ion battery electrolytes is growing year by year. Thus, providing a simple, environmentally friendly, and relatively low-cost method for directly preparing sodium-ion battery electrolytes using sodium hexafluorophosphate as the sodium salt is particularly important. Current methods typically involve first preparing sodium hexafluorophosphate and then formulating the electrolyte, which is not only complex but also results in poor yield and purity of the prepared sodium hexafluorophosphate, affecting its performance. Summary of the Invention

[0004] In view of this, the present invention provides a production process for sodium-ion battery electrolyte. The production process of the present invention can directly prepare sodium-ion battery electrolyte with sodium hexafluorophosphate as the sodium salt. The process is simple and environmentally friendly, and the yield and purity of sodium hexafluorophosphate are high.

[0005] This invention provides a production process for sodium-ion battery electrolyte, comprising the following steps:

[0006] a) Under a protective atmosphere, phosphorus pentachloride is dissolved in a carbonate solvent, then ammonium fluoride is added and the mixture is heated to carry out a solid-phase reaction; then, solid-liquid separation is performed to remove insoluble matter, yielding solution A;

[0007] b) Disperse the sodium source in a solvent to obtain solution B;

[0008] c) Under a protective atmosphere, solution B is added to solution A to react, and then solid-liquid separation is performed to remove impurities and the solvent introduced in step b) to obtain a crude sodium-ion battery electrolyte product.

[0009] d) The sodium-ion battery electrolyte is mixed with an organic solvent to obtain a sodium-ion battery electrolyte;

[0010] The organic solvent used is different from the carbonate solvent used in step a);

[0011] There is no order restriction between steps a) and b).

[0012] Preferably, in step a), the carbonate solvent is at least one of methyl ethyl carbonate, dimethyl carbonate, diethyl carbonate, ethylene carbonate, and propylene carbonate.

[0013] Preferably, in step a), the molar ratio of phosphorus pentachloride to ammonium fluoride is 1:(6.0-6.4).

[0014] Preferably, in step a), the solid-phase reaction is carried out at a temperature of 40–70°C for 4–12 hours.

[0015] Preferably, in step b), the sodium source is at least one of sodium hydroxide, sodium carbonate, sodium bicarbonate and the sodium source of formula (1);

[0016] R-ONa formula (1);

[0017] Wherein, R is selected from: alkyl groups, pyridine groups or groups shown in formula (2) of C1 to C10;

[0018] -Si-R1 Equation (2);

[0019] R1 is selected from alkyl groups of C1 to C10.

[0020] Preferably, in step b), the solvent is at least one of alcohol solvents, ketone solvents, NMP, DMF, and DMAc.

[0021] Preferably, in step c), the reaction temperature is 30–60°C and the time is 6–24 h.

[0022] Preferably, in step d), the organic solvent is at least one of ethylene carbonate, propylene carbonate, dihexyl carbonate, and dimethyl carbonate, and is different from the carbonate solvent used in step a).

[0023] Preferably, step d) specifically includes:

[0024] d1) The sodium-ion battery electrolyte is mixed with an organic solvent to obtain a basic electrolyte;

[0025] d2) Additives are added to the basic electrolyte to obtain a sodium-ion battery electrolyte;

[0026] The additive is preferably at least one selected from carbonate additives, phosphorus-containing additives, boron-containing additives, sulfur-containing additives, cyclohexane, propyl acetate, and allyl sulfone.

[0027] Preferably, the carbonate additive is vinylene carbonate;

[0028] The phosphorus-containing additive is at least one of triphenylphosphine oxide, trimethyl phosphite, and triethyl phosphate;

[0029] The boron-containing additive is tributylboronic acid ester and / or tris(trimethylsilane)boronic acid ester;

[0030] The sulfur-containing additive is methylene methyl disulfonate.

[0031] The preparation method provided by this invention involves dissolving phosphorus pentachloride in a carbonate solvent under a protective atmosphere, then adding ammonium fluoride and heating to carry out a solid-phase reaction; then, separating the solid and liquid phases to remove insoluble matter, obtaining solution A; dispersing a sodium source in a solvent to obtain solution B; then, under a protective atmosphere, adding solution B to solution A to carry out a reaction, followed by solid-liquid separation to remove impurities, obtaining a crude sodium-ion battery electrolyte product; finally, mixing the sodium-ion battery electrolyte with an organic solvent to obtain a sodium-ion battery electrolyte. This invention uses ammonium fluoride, phosphorus pentachloride, and a sodium source as raw materials, and carbonate solvents and solvents readily soluble in sodium source as reaction media. Phosphorus pentachloride dissolves in the carbonate solvent under slight heating conditions, while ammonium fluoride is insoluble in the carbonate solvent. The two undergo a solid-phase reaction to yield ammonium hexafluorophosphate and ammonium chloride. The ammonium chloride product is removed by filtration, resulting in a solution containing ammonium hexafluorophosphate. Then, the sodium source solution is slowly added directly to the ammonium hexafluorophosphate solution to react and obtain a solution containing sodium hexafluorophosphate. Further filtration removes trace impurities and the previously added sodium-soluble solvent, ultimately yielding a carbonate solution containing dissolved sodium hexafluorophosphate. Adding another carbonate solvent in a specific ratio—that is, a series of high-voltage-resistant organic solvents other than the reaction medium—results in a basic sodium-ion battery electrolyte or a novel sodium-ion battery electrolyte. Furthermore, to address some problems inherent in sodium-ion battery electrode materials, a series of functional additives can be added in the final step to construct a novel electrolyte system, thereby improving the overall performance of the sodium-ion battery. The above method can directly obtain sodium-ion battery electrolyte (sodium hexafluorophosphate), similar to a "one-stop" service. Compared with existing processes, it reduces many cumbersome intermediate steps, the reaction process is simple and easy to operate, the reaction conditions are mild and easy to control, significantly reducing production costs and making it suitable for commercial applications. Moreover, the yield and purity of sodium hexafluorophosphate in the electrolyte are high, while avoiding the use of hazardous materials such as hydrofluoric acid, thus achieving energy conservation and emission reduction. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0033] Figure 1 The image shows the XRD pattern of sodium hexafluorophosphate generated in the reaction system of Example 1 of this invention. Detailed Implementation

[0034] This invention provides a production process for sodium-ion battery electrolyte, comprising the following steps:

[0035] a) Under a protective atmosphere, phosphorus pentachloride is dissolved in a carbonate solvent, then ammonium fluoride is added and the mixture is heated to carry out a solid-phase reaction; then, solid-liquid separation is performed to remove insoluble matter, yielding solution A;

[0036] b) Disperse the sodium source in a solvent to obtain solution B;

[0037] c) Under a protective atmosphere, solution B is added to solution A to react, and then solid-liquid separation is performed to remove impurities and the solvent introduced in step b) to obtain a crude sodium-ion battery electrolyte product.

[0038] d) The sodium-ion battery electrolyte is mixed with an organic solvent to obtain a sodium-ion battery electrolyte;

[0039] The organic solvent used is different from the carbonate solvent used in step a);

[0040] There is no order restriction between steps a) and b).

[0041] Regarding step a) :

[0042] a) Under a protective atmosphere, phosphorus pentachloride is dissolved in a carbonate solvent, then ammonium fluoride is added and the temperature is raised to carry out a solid-phase reaction; then, solid-liquid separation is performed to remove insoluble matter, and solution A is obtained.

[0043] In this invention, there are no special restrictions on the type of gas used to provide the protective atmosphere; any conventional protective gas well known to those skilled in the art, such as nitrogen or argon, is acceptable.

[0044] In this invention, the carbonate solvent is preferably at least one selected from ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethylene carbonate (EC), and propylene carbonate. Using these carbonate solvents facilitates the dissolution of phosphorus pentachloride while preventing the insolubility of ammonium fluoride, which is beneficial for subsequent solid-phase reactions. In this invention, the preferred ratio of the carbonate solvent to phosphorus pentachloride is 50 mL:(0.01–0.04) mol, specifically 50 mL:0.01 mol, 50 mL:0.02 mol, 50 mL:0.03 mol, or 50 mL:0.04 mol.

[0045] In this invention, the molar ratio of phosphorus pentachloride to ammonium fluoride is preferably 1:(6.0-6.4), specifically 1:6.0, 1:6.1, 1:6.2, 1:6.3, or 1:6.4.

[0046] In this invention, the preferred temperature for the solid-phase reaction is 40–70°C, specifically 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, or 70°C. The preferred reaction time is 4–12 hours, specifically 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, or 12 hours. In a carbonate solvent reaction medium and under the aforementioned micro-heating conditions, phosphorus pentachloride and ammonium fluoride undergo a solid-phase reaction to generate ammonium hexafluorophosphate.

[0047] In this invention, the above-mentioned solid-phase reaction is preferably carried out under stirring conditions. Specifically, the preferred operating steps are as follows: phosphorus pentachloride and carbonate solvent are added to a three-necked beaker purged with a protective gas. After the phosphorus pentachloride is completely dissolved, ammonium fluoride is gradually added under magnetic stirring, and the system is heated to carry out a solid-phase reaction.

[0048] In this invention, after the above solid-phase reaction, it is preferable to first allow the mixture to stand, and then perform solid-liquid separation to remove insoluble matter. In this invention, the solid-liquid separation method is preferably filtration. The removed insoluble matter mainly consists of excess ammonium fluoride and the byproduct ammonium chloride. After the above impurity removal treatment, a solution A containing ammonium hexafluorophosphate is obtained.

[0049] Regarding step b) :

[0050] b) Disperse the sodium source in a solvent to obtain solution B.

[0051] In this invention, the sodium source is preferably at least one of sodium hydroxide, sodium carbonate, sodium bicarbonate and the sodium source of formula (1);

[0052] R-ONa formula (1);

[0053] Wherein, R is selected from: alkyl groups, pyridine groups or groups shown in formula (2) of C1 to C10;

[0054] -Si-R1 Equation (2);

[0055] R1 is selected from alkyl groups of C1 to C10.

[0056] In this invention, the molar ratio of phosphorus pentachloride to the sodium source in step a) is preferably 0.01:(0.010-0.014), specifically 0.01:0.010, 0.01:0.011, 0.010:0.012, 0.01:0.013, or 0.010:0.014.

[0057] In this invention, the solvent is a solvent readily soluble in sodium, preferably at least one selected from alcohols, ketones, NMP, DMF, and DMAc. The alcohol solvent is preferably methanol and / or ethanol. The ketone solvent is preferably acetone. In this invention, the preferred ratio of the solvent to the sodium source is 20 mL:(0.005–0.015) mol, specifically 20 mL:0.005 mol, 20 mL:0.007 mol, 20 mL:0.009 mol, 20 mL:0.011 mol, 20 mL:0.013 mol, or 20 mL:0.015 mol.

[0058] In this invention, there are no special restrictions on the method of dispersing the sodium source in the solvent, as long as the sodium source is fully dissolved in the solvent, such as by stirring to dissolve, thereby obtaining a sodium source solution, i.e., solution B.

[0059] The present invention does not impose any order restrictions on steps a) and b) above.

[0060] Regarding step c) :

[0061] c) Under a protective atmosphere, solution B is added to solution A to react, and then solid-liquid separation is performed to remove impurities and the solvent introduced in step b) to obtain a crude sodium-ion battery electrolyte product.

[0062] In this invention, there are no special restrictions on the type of gas used to provide the protective atmosphere; any conventional protective gas well known to those skilled in the art, such as nitrogen or argon, is acceptable.

[0063] In this invention, solution B is slowly added to solution A to initiate the reaction. The preferred specific steps include: slowly adding solution B to solution A under a protective atmosphere and with stirring, and then heating the reaction. The stirring speed is preferably 1000–1800 r / min, specifically 1000 r / min, 1200 r / min, 1400 r / min, 1600 r / min, or 1800 r / min. The preferred temperature for the reaction is 30–60°C, specifically 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, or 60°C. The preferred reaction time is 6–24 hours, specifically 6 hours, 8 hours, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, 22 hours, or 24 hours. Sodium hexafluorophosphate is generated through this reaction.

[0064] In this invention, after the above reaction, it is preferable to allow the mixture to stand first, and then perform solid-liquid separation to remove impurities. The preferred method of solid-liquid separation is filtration.

[0065] In this invention, after removing impurities, the readily soluble solvent for sodium introduced in step b) is then removed. The preferred method for removing the solvent introduced in step b) is rotary evaporation. After the above treatment, a crude sodium-ion battery electrolyte product is obtained.

[0066] Regarding step d) :

[0067] d) The sodium-ion battery electrolyte is mixed with an organic solvent to obtain a sodium-ion battery electrolyte.

[0068] In this invention, the organic solvent is different from the carbonate solvent used in step a). It is an organic solvent other than the reaction medium introduced in step a), preferably at least one of ethylene carbonate, propylene carbonate, dihexyl carbonate, and dimethyl carbonate. Using this solvent helps improve the high-voltage resistance of the electrolyte in actual use. For example, the basic electrolyte for sodium-ion batteries is an electrolyte of NaPF6 dissolved in ethylene carbonate and dimethyl carbonate (1 mol / L, volume ratio of the two solvents 1:1). That is, the target electrolyte contains ethylene carbonate and dimethyl carbonate in a volume ratio of 1:1. If dimethyl carbonate has already been used as a solvent in step a), then in step d), simply adding the appropriate amount of ethylene carbonate will prepare the electrolyte. For example, the solvent in the target electrolyte can be any two of ethylene carbonate, dihexyl carbonate, propylene carbonate, and dimethyl carbonate, with a volume ratio of 1:(0.6-2). Based on the solvents and amounts used in step a), the type and amount of solvent to be added in step d) can be directly determined for preparation, thus obtaining the electrolyte. Alternatively, the solvent in the target electrolyte can be any three of ethylene carbonate, dihexyl carbonate, propylene carbonate, and dimethyl carbonate, preferably ethylene carbonate, dimethyl carbonate, and dihexyl carbonate, or propylene carbonate, dimethyl carbonate, and dihexyl carbonate, or ethylene carbonate, dimethyl carbonate, and propylene carbonate, with a volume ratio of 1:(0.6-2):(0.6-2) according to the order of the substance names. Based on the solvents and amounts used in step a), the type and amount of solvent to be added in step d) can be directly determined for preparation, thus obtaining the electrolyte. For example, the solvent in the target electrolyte can be a combination of four types: ethylene carbonate, dihexyl carbonate, propylene carbonate, and dimethyl carbonate, with the ratio of ethylene carbonate: dihexyl carbonate: propylene carbonate: dimethyl carbonate = 1:(0.6-2):(0.6-2):(0.6-2). Based on the solvents and amounts used in step a), the types and amounts of solvents to be added in step d) can be directly determined for preparation, thus obtaining the electrolyte.

[0069] In existing technologies, the preparation of electrolytes often requires the prior preparation of sodium hexafluorophosphate before adding reagents to formulate the electrolyte. This is due to two main reasons: firstly, impurities introduced into the reaction system and poor product purity necessitate the separation and purification of solid sodium hexafluorophosphate before electrolyte preparation; secondly, the solvents or reaction media used in the preparation of sodium hexafluorophosphate in existing technologies are incompatible with the solvents used in sodium-ion battery electrolytes, making direct formulation impossible. However, this invention obtains a crude sodium-ion battery electrolyte product through the specific steps a) to b) described above, which can then be directly combined with organic solvents to prepare the sodium-ion battery electrolyte.

[0070] In this invention, step d) preferably includes: d1) mixing the sodium-ion battery electrolyte with an organic solvent to obtain a basic electrolyte; d2) adding an additive to the basic electrolyte to obtain a sodium-ion battery electrolyte. In this invention, the additive is preferably at least one selected from carbonate additives, phosphorus-containing additives, boron-containing additives, sulfur-containing additives, cyclohexane, propyl acetate, and allyl sulfone. The carbonate additive is preferably vinylene carbonate. The phosphorus-containing additive is preferably at least one selected from triphenylphosphine oxide, trimethyl phosphite, and triethyl phosphate. The boron-containing additive is preferably tributylboronate and / or tris(trimethylsilane)boronate. The sulfur-containing additive is preferably methylene disulfonate. In this invention, the volume of the additive is preferably 0.5% to 3% of the volume of the basic electrolyte obtained before introducing the additive, specifically 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, and 3.0%.

[0071] The preparation method provided by this invention involves dissolving phosphorus pentachloride in a carbonate solvent under a protective atmosphere, then adding ammonium fluoride and heating to carry out a solid-phase reaction; then, separating the solid and liquid phases to remove insoluble matter, obtaining solution A; dispersing a sodium source in a solvent to obtain solution B; then, under a protective atmosphere, adding solution B to solution A to carry out a reaction, followed by solid-liquid separation to remove impurities, obtaining a crude sodium-ion battery electrolyte product; finally, mixing the sodium-ion battery electrolyte with an organic solvent to obtain a sodium-ion battery electrolyte. This invention uses ammonium fluoride, phosphorus pentachloride, and a sodium source as raw materials, and carbonate solvents and solvents readily soluble in sodium source as reaction media. Phosphorus pentachloride dissolves in the carbonate solvent under slight heating conditions, while ammonium fluoride is insoluble in the carbonate solvent. The two undergo a solid-phase reaction to yield ammonium hexafluorophosphate and ammonium chloride. The ammonium chloride product is removed by filtration, resulting in a solution containing ammonium hexafluorophosphate. Then, the sodium source solution is slowly added directly to the ammonium hexafluorophosphate solution to react and obtain a solution containing sodium hexafluorophosphate. Further filtration removes trace impurities and the previously added sodium-soluble solvent, ultimately yielding a carbonate solution containing dissolved sodium hexafluorophosphate. Adding another carbonate solvent in a specific ratio—that is, a series of high-voltage-resistant organic solvents other than the reaction medium—results in a basic sodium-ion battery electrolyte or a novel sodium-ion battery electrolyte. Furthermore, to address some problems inherent in sodium-ion battery electrode materials, a series of functional additives can be added in the final step to construct a novel electrolyte system, thereby improving the overall performance of the sodium-ion battery. The above method can directly obtain sodium-ion battery electrolyte (sodium hexafluorophosphate), similar to a "one-stop" service. Compared with existing processes, it reduces many cumbersome intermediate steps, the reaction process is simple and easy to operate, the reaction conditions are mild and easy to control, significantly reducing production costs and making it suitable for commercial applications. Moreover, the yield and purity of sodium hexafluorophosphate in the electrolyte are high, while avoiding the use of hazardous materials such as hydrofluoric acid, thus achieving energy conservation and emission reduction.

[0072] This invention has the following advantages: 1. Low raw material cost, simple synthesis process, simple and easy-to-operate reaction process, mild and easy-to-control reaction conditions, and can directly prepare sodium-ion battery electrolyte (sodium hexafluorophosphate), avoiding some complex operations in existing processes; 2. The process is relatively simple, using a specific sodium source, phosphorus pentachloride and ammonium fluoride to directly react in a carbonate solvent to synthesize the initial product of sodium-ion battery electrolyte in the same equipment. Compared with existing processes, it does not require expensive process equipment, greatly reducing costs and making it suitable for large-scale commercial production; 3. It avoids the use of some highly toxic and corrosive raw materials such as hydrofluoric acid and phosphorus pentafluoride, while also saving energy and reducing emissions; 4. High yield and purity, with a yield >99% and a purity >99.5%.

[0073] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.

[0074] Example 1

[0075] a) In a 250 mL three-necked beaker under a nitrogen atmosphere, add 0.01 mol of phosphorus pentachloride and 50 mL of dimethyl carbonate solvent to dissolve it. After the phosphorus pentachloride is completely dissolved, gradually add 0.063 mol of ammonium fluoride under magnetic stirring, and heat the system to 45 °C for 6 h. Then, let it stand, filter to remove impurities, and obtain solution A.

[0076] b) Add 5.25 mmol of sodium carbonate to a 50 mL beaker, then add 50 mL of ethanol to dissolve it, to obtain solution B.

[0077] c) Under a nitrogen atmosphere, solution B was slowly added to solution A at a rotation speed of 1800 r / min and reacted at 40 °C for 8 h. Then, the mixture was allowed to stand, filtered to remove impurities, and the ethanol solvent introduced in step b) was removed by rotary evaporation at 35 °C to obtain a 0.01 mol / 50 mL dimethyl carbonate solution containing sodium hexafluorophosphate, which is the crude product of sodium-ion battery electrolyte (of which the yield of sodium hexafluorophosphate is 99.1% and the purity is 99.6%).

[0078] d) Add 50 mL of ethylene carbonate to the crude sodium-ion battery electrolyte obtained in step c) to obtain the sodium-ion battery electrolyte. The obtained electrolyte is the conventional basic electrolyte for sodium-ion batteries, namely, an electrolyte in which 1 mol / L NaPF6 is dissolved in ethylene carbonate and dimethyl carbonate (volume ratio of the two solvents 1:1).

[0079] XRD analysis was performed on sodium hexafluorophosphate in the crude sodium-ion battery electrolyte obtained in step c), and the results are as follows: Figure 1 As shown, it can be seen that it corresponds to the characteristic peak of the sodium hexafluorophosphate standard PDF card, proving that sodium hexafluorophosphate was successfully formed in step c) of the present invention.

[0080] Example 2

[0081] a) In a 100 mL three-necked beaker under a nitrogen atmosphere, add 0.01 mol of phosphorus pentachloride and 50 mL of dimethyl carbonate solvent to dissolve it. After the phosphorus pentachloride is completely dissolved, gradually add 0.063 mol of ammonium fluoride under magnetic stirring, and heat the system to 45 °C for 6 h. Then, let it stand, filter to remove impurities, and obtain solution A.

[0082] b) Add 13 mmol of sodium trimethylsilanolate to a 50 mL beaker, then add 20 mL of ethanol to dissolve it, to obtain solution B.

[0083] c) Under a nitrogen atmosphere, solution B was slowly added to solution A at a rotation speed of 1800 r / min and reacted at 40°C for 8 h. Then, the mixture was allowed to stand, filtered to remove impurities, and the ethanol solvent introduced in step b) was removed by rotary evaporation at 35°C to obtain a 0.01 mol / 50 mL dimethyl carbonate solution containing sodium hexafluorophosphate, which is the crude product of sodium-ion battery electrolyte (of which the yield of sodium hexafluorophosphate is 99.3% and the purity is 99.8%).

[0084] d) Add 50 mL of ethylene carbonate to the crude sodium-ion battery electrolyte obtained in step c) to obtain the sodium-ion battery electrolyte. The obtained electrolyte is the conventional basic electrolyte for sodium-ion batteries, namely, an electrolyte in which 1 mol / L NaPF6 is dissolved in ethylene carbonate and dimethyl carbonate (volume ratio of the two solvents 1:1).

[0085] As can be seen from the above embodiments, the method of the present invention can directly obtain sodium-ion battery electrolyte in one stop, and the yield of sodium hexafluorophosphate in the system during the preparation process is >99%, and the purity is >99.5%.

[0086] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of these embodiments are merely to aid in understanding the method and core ideas of the present invention, including the best mode, and to enable any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims. The scope of protection of this patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements similar to those expressed in the claims, or if they include equivalent structural elements that are not substantially different from those expressed in the claims, then these other embodiments should also be included within the scope of the claims.

Claims

1. A production process for a sodium-ion battery electrolyte, characterized in that, Includes the following steps: a) Under a protective atmosphere, phosphorus pentachloride is dissolved in a carbonate solvent, then ammonium fluoride is added and the temperature is raised to carry out a solid-phase reaction; then, solid-liquid separation is performed to remove insoluble matter, yielding solution A; wherein, the temperature of the solid-phase reaction is 40~70℃; b) Disperse the sodium source in a solvent to obtain solution B; c) Under a protective atmosphere, solution B is added to solution A to react, and then solid-liquid separation is performed to remove impurities and the solvent introduced in step b) to obtain a crude sodium-ion battery electrolyte product; wherein the reaction temperature is 30~60℃. d) The sodium-ion battery electrolyte is mixed with an organic solvent to obtain a sodium-ion battery electrolyte; The organic solvent used is different from the carbonate solvent used in step a); There is no order restriction between steps a) and b).

2. The production process according to claim 1, characterized in that, In step a), the carbonate solvent is at least one of methyl ethyl carbonate, dimethyl carbonate, diethyl carbonate, ethylene carbonate, and propylene carbonate.

3. The production process according to claim 1, characterized in that, In step a), the molar ratio of phosphorus pentachloride to ammonium fluoride is 1:(6.0~6.4).

4. The production process according to claim 1, characterized in that, In step a), the solid-phase reaction takes 4 to 12 hours.

5. The production process according to claim 1, characterized in that, In step b), the sodium source is at least one of sodium hydroxide, sodium carbonate, sodium bicarbonate and the sodium source of formula (1); Equation (1); Wherein, R is selected from: alkyl groups, pyridine groups or groups shown in formula (2) of C1 to C10; Equation (2); R1 is selected from C1 to C10 alkyl groups.

6. The production process according to claim 1, characterized in that, In step b), the solvent is at least one of alcohol solvents, ketone solvents, NMP, DMF and DMAc.

7. The production process according to claim 1, characterized in that, In step c), the reaction time is 6 to 24 hours.

8. The production process according to claim 1, characterized in that, In step d), the organic solvent is at least one of ethylene carbonate, propylene carbonate, dihexyl carbonate, and dimethyl carbonate, and is different from the carbonate solvent used in step a).

9. The production process according to claim 1, characterized in that, Step d) specifically includes: d1) The sodium-ion battery electrolyte is mixed with an organic solvent to obtain a basic electrolyte; d2) Additives are added to the basic electrolyte to obtain a sodium-ion battery electrolyte; The additive is at least one of carbonate additives, phosphorus-containing additives, boron-containing additives, sulfur-containing additives, cyclohexane, propyl acetate, and allyl sulfone.

10. The production process according to claim 9, characterized in that, The carbonate additive is vinylene carbonate; The phosphorus-containing additive is at least one of triphenylphosphine oxide, trimethyl phosphite, and triethyl phosphate; The boron-containing additive is tributylboronic acid ester and / or tris(trimethylsilane)boronic acid ester; The sulfur-containing additive is methylene methyl disulfonate.

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