KR20230085823A - Economical Mass Production Method of Metal bis(fluorosulfonyl)imide solution - Google Patents

Abstract

The present invention relates to a method for preparing a bis(fluorosulfonyl)imide metal salt solution, and more particularly, to a metallization reagent in powder form using bis(fluorosulfonyl)imide represented by Formula 1 as a starting material and The present invention relates to a method for preparing the bis(fluorosulfonyl)imide metal salt powder represented by Chemical Formula 2 by reacting the aqueous solution of the bis(fluorosulfonyl)imide metal salt represented by Chemical Formula 2 with an azeotropic distillation method.
The manufacturing method according to the present invention reacts the bis(fluorosulfonyl)imide compound directly with a powdery metallization reagent without a solvent, thereby generating no related waste, and unlike the prior art, environmentally friendly bis(fluorosulfonyl) Imide metal salt can be produced, and by rapidly concentrating using azeotropic distillation to remove a small amount of water within 10% by weight generated during the reaction, a high-yield and high-purity bis(fluorosulfonyl)imide metal salt solution can be easily obtained. It is very economical because it can be mass-produced, has a simple manufacturing process compared to powder form, and has excellent storage and use.

Description

Economical Mass Production Method of Metal bis(fluorosulfonyl)imide solution}

The present invention relates to a novel method for producing a liquid bis(fluorosulfonyl)imide metal salt product, and more particularly, to a novel method for preparing bis(fluorosulfonyl)imide or ammonium bis(fluorosulfonyl)imide as a starting material. It relates to an economical manufacturing method for mass-producing a bis(fluorosulfonyl)imide metal salt product very efficiently by reacting the salt with a metallization reagent in the form of a powder and concentrating or concentrating/drying the product.

Recently, with the commercialization of various mobile devices, the need for high-performance secondary batteries is increasing, and with the commercialization of electric vehicles and hybrid electric vehicles and the development of electric storage devices, secondary batteries equipped with performance such as high power, high energy density, and high discharge voltage Batteries were needed.

The importance of the lithium salt in the composition of the electrolyte solution suitable for this is emerging. Accordingly, the need to economically prepare a lithium bis(fluorosulfonyl)imide salt has emerged.

Lithium bis(fluorosulfonyl)imide salt has advantages over other lithium salt compounds such as lithium hexafluorophosphate with advantages such as high thermal stability, high electrical conductivity, low corrosion resistance, excellent low-temperature performance, and efficient film formation on the anode and cathode. This is a lot.

Recently, electric vehicles have been spotlighted as an eco-friendly means of transportation that can replace conventional internal combustion engine vehicles, and related markets are rapidly expanding. Accordingly, a characteristic lithium secondary battery is required, and in particular, lithium bis(fluorosulfonyl)imide salt exhibits required performance that meets the requirements of such a lithium secondary battery for electric vehicles, and its commercial importance is increasing.

On the other hand, due to various limitations, it is still not easy to mass-produce lithium bis(fluorosulfonyl)imide salt inexpensively and economically.

A conventional method for producing lithium bis(fluorosulfonyl)imide, in which many studies have been conducted, will be described as follows.

U.S. Patent No. 8,926,930 discloses that bis(fluorosulfonyl)imide in an organic layer and lithium hydroxide in an aqueous layer are reacted to move lithium bis(fluorosulfonyl)imide to an organic layer, and the organic layer is concentrated to obtain lithium bis(fluorosulfonyl)imide. Although sulfonyl)imide is obtained, in order to prevent the loss of lithium bis(fluorosulfonyl)imide to the water layer, an excessive amount of organic solvent is used and productivity is deteriorated, such as excessive wastewater.

In addition, in International Publication No. WO2016/184176, lithium bis(fluorosulfonyl)imide is prepared by reacting bis(fluorosulfonyl)imide with lithiation reagents such as lithium hydroxide monohydrate, lithium carbonate, and lithium hydrogencarbonate. Lithium bis(fluorosulfonyl)imide is prepared by adding thionyl chloride (SOCl ₂ ) in order to remove moisture generated during the preparation. However, the excess thionyl chloride added must be removed, and the content of impurities such as Cl ^- and SO ₄ ^2- is high in the lithium bis(fluorosulfonyl)imide prepared under acidic reaction conditions. These impurities may cause corrosion problems when applied to lithium secondary batteries, which may be a fatal problem for long-term stable operation.

In addition, in Korean Patent Publication No. 10-2020-0005970, there is an example of using lithium-t-butoxide as a lithiation reagent to eliminate moisture generation. Lithium-t-butoxide is lithium oxide monohydrate, a commonly used lithiation reagent. , Lithium bis(fluorosulfonyl)imide prepared by this method has very low price competitiveness, since the reagent price is more than three times higher than that of lithium carbonate, and considering the molecular weight, it is six times the actual unit price.

In addition, commercial products of bis(fluorosulfony)imide metal salts are generally in the form of powder, but it takes a long drying time to manufacture powder, and large investment costs such as drying rooms and dehumidifying rooms are required for mass production. In addition, there is a problem in that moisture must be strictly managed in the process of storing the metal salt powder and preparing the electrolyte solution.

As such, many studies have been conducted on the production of bis(fluorosulfonyl)imide metal salts including lithium bis(fluorosulfonyl)imide, but in this case, mass production is possible more economically, and storage is easy and environmentally friendly. Methods for preparing bis(fluorosulfonyl)imide metal salts are still in demand.

US Patent No. 8,926,930 (Registration date: 2015.01.06) International Patent Publication No. WO2016/184176 (published date: 2017.11.29) Korean Patent Publication No. 10-2020-0005970 (published date: 2020.01.17)

Accordingly, an object of the present invention is to provide a method for mass-producing various types of bis(fluorosulfonyl)imide metal salts in an eco-friendly, economical and efficient manner.

Another object of the present invention is to provide a high-purity bis(fluorosulfonyl)imide metal salt prepared by the above preparation method.

While devising a method for preparing a liquid bis(fluorosulfonyl)imide metal salt solution more easily with high purity and high yield through an environmentally friendly and simple process, the present inventors found bis(fluorosulfonyl) as a starting material By reacting imide or ammonium bis(fluorosulfonyl)imide with a metallization reagent in the form of a powder in the presence of a solvent to prepare bis(fluorosulfonyl)imide metal salt, efficiently removing water generated to obtain high purity and The present invention was completed after finding out that a solution of bis(fluorosulfonyl)imide metal salt can be easily mass-produced in high yield.

In this manufacturing method, when preparing the bis(fluorosulfonyl)imide metal salt, the metallization reagent is used in the form of a metal powder rather than an aqueous solution, so there is no wastewater generation. Accordingly, it is possible to produce bis(fluorosulfonyl)imide metal salt in a very eco-friendly manner, and a solution of bis(fluorosulfonyl)imide metal salt with high purity and high yield can be obtained by proceeding with a simple water removal process. It can be easily mass-produced.

Accordingly, the present invention ((i) reacts a bis(fluorosulfonyl)imide compound represented by Formula 1 with a metallization reagent in powder form in the presence of a solvent to obtain bis(fluorosulfonyl)imide represented by Formula 2 below preparing an aqueous solution of phonyl)imide metal salt; and

(ii) concentrating the aqueous solution of the bis(fluorosulfonyl)imide metal salt to prepare a bis(fluorosulfonyl)imide metal salt solution represented by Formula 2 below, bis(fluorosulfonyl) ) Provides a method for preparing an imide metal salt solution:

[Formula 1]

[Formula 2]

In Formula 1, A is H or NR ¹ R ² R ³ R ⁴ , R ¹ to R ⁴ may be the same or different, and H or carbon containing a C1 to C20 linear or branched heteroatom,

In Formula 2, M is lithium, sodium or potassium.

In addition, the present invention provides a bis(fluorosulfonyl)imide metal salt solution having a purity of 99% or more prepared by the above preparation method.

The method for preparing a bis(fluorosulfonyl)imide metal salt solution according to the present invention reacts a bis(fluorosulfonyl)imide compound with a powdery metallization reagent, so that no waste is generated, unlike the prior art. An environmentally friendly bis(fluorosulfonyl)imide metal salt solution can be prepared.

In addition, this preparation method is very simple and quickly concentrated using azeotropic distillation to remove a small amount of water within 10% by weight generated during the reaction, thereby obtaining a high yield and high purity bis(fluorosulfonyl)imide metal salt solution. The bis(fluorosulfonyl)imide metal salt solution prepared according to the present invention is very economical because it can be easily mass-produced, the manufacturing process is simple compared to powder form, and the storage and use are excellent. , it can be widely applied to secondary batteries or antistatic agents that require high output, such as power tools.

Hereinafter, the present invention will be described in more detail.

First, looking at the prior art for preparing a bis(fluorosulfonyl)imide metal salt, the reaction proceeds to a solution phase of the bis(fluorosulfonyl)imide metal salt in various ways, and the solvent is evaporated to form a concentrated solution. The solvent of 2 is introduced to induce crystallization of the bis(fluorosulfonyl)imide metal salt, and the obtained crystal is filtered out, collected, and dried to prepare. In most cases, a solution phase of bis(fluorosulfonyl)imide metal salt is prepared by contacting an organic solution of bis(fluorosulfonyl)imide or an ammonium salt of bis(fluorosulfonyl)imide with an aqueous solution of a metallizing reagent. .

In most cases, bis(fluorosulfonyl)imide metal salts have an exceptionally high affinity for solvents or water, and when commercialized by the above method, some of them are dissolved in water and lost. and the purity of the crystallized product is not high. This is because some of the pure bis(fluorosulfonyl)imide metal salt products are lost by dissolving in solvents or water. In addition, since a second solvent insoluble in the product must be used inevitably in the crystallization process, the solvent mixture is generated as waste, and wastewater resulting from the aqueous solution of the metallization reagent is also generated.

As described above, in this process, a small amount of water has a very high affinity for bis(fluorosulfonyl)imide metal salt, so it is not removed. Since it must be manufactured, it is not easy to remove a small amount of water by conventional methods, and the purity of the product may be reduced due to the generation of impurities through a process such as raising the temperature for a long time in the removal process. In addition, thionyl chloride, etc. is used to remove a small amount of water, but hydrochloric acid gas and SO _x gas are inevitably generated, increasing the acidity in the product and increasing the content of impurities such as Cl ^- and SO ₄ ^2- in the product. It is completely undesirable, such as causing deterioration in quality. In addition, it takes a high temperature of 60 ℃ or more, a high vacuum of 1.0 mmHg or less, and a long period of about 24 to 48 hours to concentrate water under reduced pressure in a general method, so it is not economical at all and is not suitable for commercial production.

On the other hand, the present inventors contact bis(fluorosulfonyl)imide or ammonium salt of bis(fluorosulfonyl)imide with a metallization reagent to obtain bis(fluorosulfonyl)imide in a liquid-solid reaction or solid-state reaction. It was found that de metal salts can be prepared with high purity. As a representative example, when the metal is lithium and the solidification reagent is lithium hydroxide monohydrate, lithium bis(fluorosulfonyl)imide can be produced in high yield and high purity. After removing the insoluble matter through simple filtration, the purity, color, and impurity content were all satisfied with the standard. The problem was whether water of about 10% by weight can be removed in a short time without deterioration in product purity to 100 ppm or less, preferably 50 ppm or less, which is the product standard.

Accordingly, the present inventors, while devising various methods, used a useful solvent capable of causing azeotropic distillation with water to azeotropic distillation of around 10% by weight of water in the bis(fluorosulfonyl)imide metal salt reactant. Checked if it could be removed. In this case, the azeotropic distillation solvent can be commercialized as a solution of bis(fluorosulfonyl)imide metal salt after removing water and simply filtering out the insoluble matter when using a solvent that is mixed with bis(fluorosulfonyl)imide metal salt. , When the azeotropic distillation solvent uses a solvent immiscible with the bis(fluorosulfonyl)imide metal salt, water is also removed and the bis(fluorosulfonyl)imide metal salt product is crystallized and precipitated, easily filtering and drying the product. productization is possible.

Through such a simple process, both a powder product and a solution product of the bis(fluorosulfonyl)imide metal salt can be prepared. In particular, a solution product of bis(fluorosulfonyl)imide metal salt has not been commercialized until now, and in the case of this product, which is a secondary battery electrolyte, the solution product has several advantages.

That is, the bis(fluorosulfonyl)imide metal salt has strong hygroscopicity and aggregation. Therefore, in the case of powder, very careful sealing is required, and moisture must be strictly excluded even during storage. In addition, there are inconveniences in use, such as the need to block moisture as much as possible even when the electrolyte is introduced to make the electrolyte. In fact, for this reason, it is packaged and used in a small package of about 5 kg.

On the other hand, if the solvent in the solution product of the bis(fluorosulfonyl)imide metal salt is the solvent used in the composition of the electrolyte solution, it is much more free from moisture, and it is very convenient because it is possible to freely add the liquid without the risk of moisture. On the other hand, since powder products must be used in some cases, it is very important to develop a process that can freely produce powder and solution products. Surprisingly, it is possible to easily separate and remove water in a short time by using the azeotropic distillation method, which is a simple water removal method, so that high-purity lithium bis(fluorosulfonyl)imide products with a water content of 100 ppm or less can be produced without deterioration in purity. Confirmed. When the purity, color, and impurity content of the lithium bis(fluorosulfonyl)imide product manufactured in this way were analyzed, all of them satisfied the standard.

Through this, it was confirmed that the bis(fluorosulfonyl)imide metal salt can be easily and industrially synthesized in large quantities. Conventionally, wastewater is unavoidable due to the use of an excessive amount of water by using the metallization reagent in the form of an aqueous solution in the metallization step. There was no

In addition, conventionally, bis(fluorosulfonyl)imide metal salt is concentrated in an organic solvent with difficulty, a product is produced from the concentrate by crystallization, and the product is separated by filtering and drying to produce a product. Through this process, economic feasibility and workability deteriorate due to reduction in working time, purity and yield, generation of waste, and increase in process cost, but the present inventor's development process performs this at once, but it is found to be far superior to the existing process in terms of purity, yield, environment, and economic feasibility. and completed the present invention.

Hereinafter, the present invention will be described in more detail as one embodiment.

The present invention (i) reacts a bis(fluorosulfonyl)imide compound represented by Chemical Formula 1 with a metallization reagent in powder form in the presence of a solvent to obtain bis(fluorosulfonyl)imide represented by Chemical Formula 2 below preparing an aqueous solution of a de-metal salt; and

(ii) concentrating the aqueous solution of the bis(fluorosulfonyl)imide metal salt to prepare a bis(fluorosulfonyl)imide metal salt solution represented by Formula 2 below, bis(fluorosulfonyl) ) Provides a method for preparing an imide metal salt solution:

[Formula 1]

[Formula 2]

In Formula 1, A is H or NR ¹ R ² R ³ R ⁴ , R ¹ to R ⁴ may be the same or different, and H or carbon containing a C1 to C20 linear or branched heteroatom,

In Formula 2, M may be lithium, sodium or potassium.

In the present invention, the bis(fluorosulfonyl)imide metal salt represented by Chemical Formula 2 can be prepared as shown in Scheme 1 below:

[Scheme 1]

First, step (i) is a step of preparing an aqueous solution of bis(fluorosulfonyl)imide metal salt by reacting the bis(fluorosulfonyl)imide compound with a metallization reagent in powder form.

In the present invention, it is preferable to use a metal salt powder as a metallization reagent for metallization. Conventionally, the metal salt powder was prepared in the form of an aqueous solution and then used. However, the use of such an aqueous solution had a limitation in that the concentration of the reaction solution had to be diluted to prevent the loss of the bis(fluorosulfonyl)imide metal salt into the water layer. However, the manufacturing method of the present invention is advantageous in mass production because it is possible to perform the reaction at a high concentration because the metal salt powder is used as it is to proceed with the reaction, and it is very environmentally friendly because there is no generation of unnecessary wastewater. This is different from the conventional manufacturing method.

Specifically, the bis(fluorosulfonyl)imide compound is bis(fluorosulfonyl)imide, ammonium bis(fluorosulfonyl)imide, alkylammonium bis(fluorosulfonyl)imide, di At least one selected from the group consisting of alkylammonium bis(fluorosulfonyl)imide, trialkylammonium bis(fluorosulfonyl)imide, and tetraalkylammonium bis(fluorosulfonyl)imide may be included. .

In detail, the metallization reagent may be at least one selected from the group consisting of a hydroxide salt, a carbonate salt, and a bicarbonate salt of a metal selected from lithium, sodium, or potassium, but is not limited thereto. In this case, the metallization reagent may be used in an equivalent ratio of 1.0 to 1.1 relative to bis(fluorosulfonyl)imide, but is not limited thereto.

Depending on the metalation reagent used in step (i), 1 to 2 equivalents of water are generated, which is water generated as a result of the reaction between bis(fluorosulfonyl)imide and the metalation reagent. For example, when the metalation reagent is sodium hydroxide, sodium bis(fluorosulfonyl)imide is synthesized as shown in Reaction Scheme 1, and 1 equivalent of water is generated together. When the metallization reagent is lithium hydroxide monohydrate, lithium bis(fluorosulfonyl)imide is synthesized by the reaction between bis(fluorosulfonyl)imide and lithium hydroxide with 1 equivalent of water, and 1 equivalent of water is 1 equivalent of water is generated from lithium hydroxide monohydrate. Thus, in this case, 2 equivalents of water are generated.

In step (i), the reaction temperature is -30 ° C to 100 ° C and the reaction time is preferably 0.5 to 4 hours. .

In the case of using a solvent in step (i), the usable solvent is any one ether selected from the group consisting of diethyl ether, diisopropyl ether, and methyl-t-butyl ether; alkoxyethanes such as dimethoxyethane and diethoxyethane; esters selected from the group consisting of methyl acetate, ethyl acetate, propyl acetate, and butyl acetate; nitriles which are any one selected from the group consisting of acetonitrile, propionitrile, and butyronitrile; nitroalkanes selected from the group consisting of nitromethane, nitroethane, nitropropane, and nitrobutane; hydrocarbons selected from the group consisting of pentane, hexane, and heptane; Aromatics, such as benzene, toluene, and xylene; alcohols selected from the group consisting of methanol, ethanol, propanol, and butanol; ketones selected from the group consisting of acetone, methyl ethyl ketone, and methyl isopropyl ketone; and dialkyl carbonates selected from the group consisting of dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate; It is at least one selected from ethylene carbonate, propylene carbonate, and butylene carbonate.

In the step (i), the concentration of the bis(fluorosulfonyl)imide metal salt in the aqueous solution of the bis(fluorosulfonyl)imide metal salt may be 0.1 wt% to 95.0 wt%.

In addition, a step of filtering and removing insolubles from the product produced after step (i) may be performed, but such a purification or filtration step is not necessarily required.

Next, step (ii) is to quickly dehydrate and dry the water generated from the product containing a small amount of water in (i) using a suitable drying facility to prepare a bis(fluorosulfonyl)imide metal salt solution It is a step.

In the case of using a solvent in step (ii), the usable solvent is any one ether selected from the group consisting of diethyl ether, diisopropyl ether, and methyl-t-butyl ether; alkoxyethanes such as dimethoxyethane and diethoxyethane; esters selected from the group consisting of methyl acetate, ethyl acetate, propyl acetate, and butyl acetate; nitriles which are any one selected from the group consisting of acetonitrile, propionitrile, and butyronitrile; nitroalkanes selected from the group consisting of nitromethane, nitroethane, nitropropane, and nitrobutane; hydrocarbons selected from the group consisting of pentane, hexane, and heptane; Aromatics, such as benzene, toluene, and xylene; alcohols selected from the group consisting of methanol, ethanol, propanol, and butanol; ketones selected from the group consisting of acetone, methyl ethyl ketone, and methyl isopropyl ketone; and dialkyl carbonates selected from the group consisting of dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate; It is at least one selected from ethylene carbonate, propylene carbonate, and butylene carbonate.

In the dehydration, about 10% by weight of water in the bis(fluorosulfonyl)imide metal salt reactant may be removed by azeotropic distillation using a solvent capable of causing azeotropic distillation with water. Azeotropic distillation can be carried out under normal pressure or reduced pressure. In this case, when using a solvent that is mixed with bis(fluorosulfonyl)imide metal salt, the bis(fluorosulfonyl) ) It can be commercialized as a solution of the imide metal salt, and if the azeotropic distillation solvent is a solvent immiscible with the bis(fluorosulfonyl)imide metal salt, water is also removed and the bis(fluorosulfonyl)imide metal salt product It is crystallized and precipitated and can be easily commercialized in powder form through filtering and drying processes.

Through such a simple process, a solution product of bis(fluorosulfonyl)imide metal salt can be prepared.

In the case of solution products, drying for additional moisture removal is possible using a general molecular sieve if necessary, and selective moisture removal is possible without product loss by using a product with a core size of 3 to 4 angstroms. possible.

In addition, the molecular sieve can efficiently remove moisture from the product by adding 5 to 20 parts by weight based on 100 parts by weight of the bis(fluorosulfonyl)imide solution.

In addition, the present invention provides a bis(fluorosulfonyl)imide metal salt solution having a high purity of 99% or more, prepared by the above preparation method. The bis(fluorosulfonyl)imide metal salt solution prepared according to the present invention is highly pure and contains very few impurities, so when used as a metal salt of an electrolyte for a secondary battery, the electrochemical characteristics, output and life characteristics of a secondary battery can be improved. .

In addition, the bis(fluorosulfonyl)imide metal salt solution is a solution containing 1 to 30 ppm of water, and is easy to store due to low stress on water content control. It has the advantage of excellent usability because the melting process can be omitted.

Hereinafter, a new method for preparing the bis(fluorosulfonyl)imide metal salt according to the present invention will be described in more detail by the following examples. However, the present invention is not limited by these examples.

Example 1. Ammonium Bis(fluorosulfonyl)imide and lithium hydroxide monohydrate powdered lithium Bis(fluorosulfonyl)imide preparation of solution

297.3 g of ethyl methyl carbonate was added to 99.1 g of ammonium bis(fluorosulfonyl)imide at 20 ° C. in a 1000 mL container equipped with a stirrer, Dean-Stark trap, condenser and thermometer to dissolve it. , 21.0 g of lithium hydroxide monohydrate was slowly added at 0 ° C, and the temperature was gradually raised to 20 ° C while stirring, and reacted until the reaction was completed.

Thereafter, the insoluble content was filtered with filter paper, and a transparent liquid lithium bis(fluorosulfonyl)imide solution was flowed under a reduced pressure of 100 torr to obtain water at the top of a Dean-Stark trap. After the amount of water obtained was lubricated until it reached the theoretical amount, the reactant was slowly cooled to room temperature. Thereafter, the insoluble content was filtered with filter paper to obtain 388.0 g of a lithium bis(fluorosulfonyl)imide solution as a transparent liquid. (Yield: 97%, Purity: 99.4%, Acidity: 4 ppm, Cl ^- : 0.6 ppm, SO ₄ ^2- : 1.0 ppm, moisture: 28 ppm).

Example 2. Ammonium Bis(fluorosulfonyl)imide and Using Sodium Hydroxide Powder sodium Bis(fluorosulfonyl)imide preparation of solution

390.7 g of a sodium bis(fluorosulfonyl)imide solution was obtained in the same manner as in Example 1, except that 20.0 g of sodium hydroxide was used instead of 21.0 g of lithium hydroxide monohydrate (yield: 95%, purity: 99.4). %, acidity: 5 ppm, Cl ^- : 0.8 ppm, SO ₄ ^2- : 1.1 ppm, moisture: 25 ppm).

Example 3. Ammonium Bis(fluorosulfonyl)imide and Calcium Using Potassium Hydroxide Powder Bis(fluorosulfonyl)imide solution preparation

400.3 g of a potassium bis(fluorosulfonyl)imide solution was obtained in the same manner as in Example 1, except that 33.0 g of potassium hydroxide was used instead of 21.0 g of lithium hydroxide monohydrate (yield: 94%, purity: 99.5). %, acidity: 5 ppm, Cl ^- : 0.7 ppm, SO ₄ ^2- : 1.0 ppm, moisture: 28 ppm).

Example 4. Lithium Bis(fluorosulfonyl)imide Further drying of the solution

Under a nitrogen atmosphere, 38.8 g of a Molecular Seive 4 Angstrom standard was added to 388.0 g of the lithium bis(fluorosulfonyl)imide solution obtained in Example 1 in a 1000 mL container equipped with a stirrer and a thermometer at 20 ° C. It was added, stirred, and dried.

After drying, the molecular sieve and the insoluble content were filtered with filter paper, and when the moisture of the obtained lithium bis(fluorosulfonyl)imide solution was measured, lithium bis(fluorosulfonyl)imide dried from an initial 28 ppm to 8 ppm A solution was obtained.

As described above, although the present invention has been described by limited examples, the present invention is not limited thereto, and the technical spirit of the present invention and the claims to be described below are made by those skilled in the art to which the present invention belongs. Of course, various modifications and variations are possible within the equivalent range of the scope.

Claims (12)

(i) A bis(fluorosulfonyl)imide compound represented by the following formula (1) is reacted with a metallization reagent in powder form in the presence of a solvent to obtain a bis(fluorosulfonyl)imide metal salt represented by the following formula (2) preparing an aqueous solution; and
(ii) concentrating the aqueous solution of the bis(fluorosulfonyl)imide metal salt to prepare a bis(fluorosulfonyl)imide metal salt solution represented by Formula 2 below, bis(fluorosulfonyl) ) Preparation method of imide metal salt solution:
[Formula 1]

[Formula 2]

In Formula 1, A is H or NR ¹ R ² R ³ R ⁴ , R ¹ to R ⁴ may be the same or different, and H or carbon containing a C1 to C20 linear or branched heteroatom,
In Formula 2, M is lithium, sodium or potassium. According to claim 1,
The bis(fluorosulfonyl)imide compound is bis(fluorosulfonyl)imide, ammonium bis(fluorosulfonyl)imide, alkylammonium bis(fluorosulfonyl)imide, dialkylammonium bis(fluorosulfonyl)imide, Bis (fluorosulfonyl) containing at least one selected from the group consisting of rosulfonyl) imide, trialkylammonium bis (fluorosulfonyl) imide and tetraalkylammonium bis (fluorosulfonyl) imide Method for preparing an imide metal salt solution. According to claim 1,
The metallization reagent is one selected from the group consisting of a hydroxide salt, a carbonate salt, and a bicarbonate salt of a metal selected from lithium, sodium, or potassium. Preparation of a bis (fluorosulfonyl) imide metal salt solution method. According to claim 1,
The metallization reagent is a method for preparing a bis (fluorosulfonyl) imide metal salt solution, characterized in that used in an equivalent ratio of 1.0 to 1.1 compared to the bis (fluorosulfonyl) imide compound. According to claim 1,
Concentration in step (ii) is characterized in that the water is removed using a solvent capable of azeotropic distillation with water, a method for producing a bis (fluorosulfonyl) imide metal salt solution. According to claim 1,
The solvent is any one ether selected from the group consisting of diethyl ether, diisopropyl ether, and methyl-t-butyl ether; alkoxyethanes such as dimethoxyethane and diethoxyethane; esters selected from the group consisting of methyl acetate, ethyl acetate, propyl acetate, and butyl acetate; nitriles which are any one selected from the group consisting of acetonitrile, propionitrile, and butyronitrile; Nitroalkanes selected from the group consisting of nitromethane, nitroethane, nitropropane, and nitrobutane; Hydrocarbons selected from the group consisting of pentane, hexane, and heptane; Aromatics, such as benzene, toluene, and xylene; alcohols selected from the group consisting of methanol, ethanol, propanol, and butanol; ketones selected from the group consisting of acetone, methyl ethyl ketone, and methyl isopropyl ketone; and dialkyl carbonates selected from the group consisting of dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate; Method for producing a bis (fluorosulfonyl) imide metal salt solution, characterized in that at least one selected from ethylene carbonate, propylene carbonate, butylene carbonate. According to claim 1,
In the step (i), the concentration of the bis (fluorosulfonyl) imide metal salt in the aqueous solution of the bis (fluorosulfonyl) imide metal salt is 0.1% by weight to 95.0% by weight. Method for preparing a phonyl)imide metal salt solution. According to claim 1,
In step (ii), a drying process is additionally performed,
The method for producing a bis (fluorosulfonyl) imide metal salt solution, characterized in that the drying is performed by passing through a molecular sieve. According to claim 8,
The method for producing a bis (fluorosulfonyl) imide metal salt solution, characterized in that the molecular sieve has a core size of 2 to 5 Angstroms. According to claim 8,
The molecular sieve is a method for producing a bis (fluorosulfonyl) imide metal salt solution, characterized in that 5 to 20 parts by weight is added based on 100 parts by weight of the bis (fluorosulfonyl) imide solution. A bis(fluorosulfonyl)imide metal salt solution having a purity of 99% or more, prepared by the method of any one of claims 1 to 10. According to claim 11,
The bis (fluorosulfonyl) imide metal salt solution is characterized in that the water content is 1 to 30 ppm, bis (fluorosulfonyl) imide metal salt solution.