Fluorosulfonylimide salt and preparation method therefor

Abstract

A fluorosulfonylimide salt is disclosed. This fluorosulfonylimide salt represented by chemical formula (Ib) of the present invention contains at least one of an impurity represented by chemical formula (IIb), [NS2O5F]2-, and an impurity represented by chemical formula (IIIb), [NS2O6]3-, wherein the content of [NS2O5F]2- is 10,000 ppm or less, and the content of [NS2O6]3- is 10,000 ppm or less (in chemical formula (Ib), M2 is one of Li, Na, K, Ca, Mg, Zn, Sb, Rb, and Cs; and A1 is a fluorine atom, or an alkyl group having 1 to 6 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom). … chemical formula (Ib) … chemical formula (IIb) … chemical formula (IIIb) The fluorosulfonylimide salt according to the present invention can reduce the corrosion of electrolytes, additives, and current collectors.

Description

Fluorosulfonylimide salt and method for producing the same

[0001] The present invention relates to a fluorosulfonylimide salt and a method for producing the same, and more particularly, to a fluorosulfonylimide salt from which impurities are removed by adding a chlorinating reagent and a method for producing the same.

[0002] Fluorosulfonylimide salts (e.g., fluorosulfonylimide alkali metal salts, etc.) are compounds used in various applications, such as electrolytes, especially electrolytes for lithium secondary batteries, fuel cell electrolytes, selective electrophilic fluorinating agents, and infrared absorbing dyes.

[0003] Conventional methods for producing fluorosulfonylimide salts have involved the halogen exchange of chlorosulfonylimide. For example, a method in which chlorosulfonyl isocyanate is reacted with chlorosulfonic acid to produce bischlorosulfonylimide, and then bischlorosulfonylimide is halogen exchanged to ultimately produce bisfluorosulfonylimide lithium salt is widely applied industrially.

[0004] However, the bisfluorosulfonylimide lithium salt manufactured in this way was weakly acidic and had the problem of corroding the electrolyte, additives, and current collector.

[0005] As a result of studying the reason why bisfluorosulfonylimide lithium salt corrodes the electrolyte, additives, and current collector, it was confirmed that bisfluorosulfonylimide lithium salt contains ions containing sulfonic acid groups (-SO3H) or sulfonic acid salts (-SO3M), which release hydrogen ions within the electrolyte or decompose the electrolyte and additives to generate hydrofluoric acid, thereby corroding the electrolyte, additives, and current collector.

[0006] Accordingly, the present invention has been devised to solve the above-described problems, and provides a fluorosulfonylimide salt and a method for producing the same, which reduce corrosion of electrolytes, additives, and current collectors.

[0007] In addition, the present invention provides bischlorosulfonylimide with reduced impurities, which is an intermediate material for producing a fluorosulfonylimide salt, and a method for producing the same.

[0008] In addition, the present invention provides a fluorosulfonylimide having reduced impurities, which is an intermediate material for producing a fluorosulfonylimide salt, and a method for producing the same.

[0009] Other objects of the present invention will become more apparent through the preferred embodiments described below.

[0010] Bischlorosulfonylimide according to one aspect of the present invention contains at least one of an impurity H2O5NClS2 represented by the following chemical formula (IIa) in an amount of 10,000 ppm or less and an impurity H3O6NS2 represented by the following chemical formula (IIIa) in an amount of 10,000 ppm or less.

[0011] …chemical formula (IIa)

[0012] …chemical formula (IIIa)

[0013] Here, by adding a chlorinating reagent in the above bischlorosulfonylimide manufacturing process, the H2O5NClS2 can be 10,000 ppm or less and the H3O6NS2 can be 10,000 ppm or less.

[0014] Here, the above H2O5NClS2 may be 7,100 ppm or less, and the above H3O6NS2 may be 6,700 ppm or less.

[0015] Here, the chlorinating reagent may be at least one selected from SOCl2, SO2Cl2, COCl2, C2O2Cl2, POCl3, PCl5, SbCl3, ClSO2NCO, SO2(NCO)2, SiCl4, ICl, ICl3, S2Cl2, SCl2, PCl3, COCl2, C6H5CCl3.

[0016] According to another aspect of the present invention, the fluorosulfonylimide represented by the chemical formula (Ia) contains an impurity [NS2O5F] represented by the following chemical formula (IIb). 2- and an impurity [NS2O6] represented by the following chemical formula (IIIb). 3- Containing at least one of [NS2O5F], wherein the chlorinating reagent is added during the manufacturing process. 2- is less than 10,000ppm and the above [NS2O6] 3- is less than 10,000ppm.

[0017] …chemical formula (Ia)

[0018] …chemical formula (IIb)

[0019] …chemical formula (IIIb)

[0020] (However, in the above chemical formula (Ia), M1 is H, and A1 is a fluorine atom or an alkyl group having 1 to 6 carbon atoms in which one or more hydrogen atoms are replaced with a fluorine atom.)

[0021] Here, the above [NS2O5F] 2- is less than 7,100 ppm, and the above [NS2O6] 3- may be less than 6,700 ppm.

[0022] According to another aspect of the present invention, a fluorosulfonylimide salt represented by chemical formula (Ia) comprises an impurity [NS2O5F] represented by the following chemical formula (IIb). 2- and an impurity [NS2O6] represented by the following chemical formula (IIIb). 3- Containing at least one of [NS2O5F], wherein the chlorinating reagent is added during the manufacturing process. 2- is less than 10,000ppm and the above [NS2O6] 3- is less than 10,000ppm.

[0023] …chemical formula (Ia)

[0024] …chemical formula (IIb)

[0025] …chemical formula (IIIb)

[0026] (However, in the above chemical formula (Ia), M1 is one of NH4, Li, Na, K, Ca, Mg, Zn, Sb, Rb, and Cs, and A1 is a fluorine atom or an alkyl group having 1 to 6 carbon atoms in which one or more hydrogen atoms are replaced with a fluorine atom.)

[0027] Here, the above [NS2O5F] 2- is less than 7,100 ppm, and the above [NS2O6] 3- may be less than 6,700 ppm.

[0028] According to another aspect of the present invention, a fluorosulfonylimide salt represented by chemical formula (Ib) comprises an impurity [NS2O5F] represented by the following chemical formula (IIb): 2- and an impurity [NS2O6] represented by the following chemical formula (IIIb). 3- Containing at least one of the above [NS2O5F] 2- is less than 10,000 ppm and the above [NS2O6] 3- is less than 10,000ppm.

[0029] …chemical formula (Ib)

[0030] …chemical formula (IIb)

[0031] …chemical formula (IIIb)

[0032]

[0033] (However, in the chemical formula (Ib), M2 is one of Li, Na, K, Ca, Mg, Zn, Sb, Rb, and Cs, and A1 is a fluorine atom or an alkyl group having 1 to 6 carbon atoms in which one or more hydrogen atoms are replaced with a fluorine atom.)

[0034] Here, the above [NS2O5F] 2- is less than 7,100 ppm and the above [NS2O6] 3- may be less than 6,700 ppm.

[0035] Here, the above [NS2O5F] 2- is less than 6,300 ppm and the above [NS2O6] 3- may be less than 5,200 ppm.

[0036] Here, the above [NS2O5F] 2- is less than 289 ppm and the above [NS2O6] 3- may be less than 325 ppm.

[0037] Here, the above [NS2O5F] 2- is less than 187 ppm and the above [NS2O6] 3- may be less than 124 ppm.

[0038] Here, the fluorosulfonylimide salt may have a pH of 6 or more and 9 or less in an aqueous solution state.

[0039] An electrolyte according to another aspect of the present invention comprises the fluorosulfonylimide or fluorosulfonylimide salt.

[0040] An electrochemical device according to another aspect of the present invention comprises the electrolyte.

[0041] A method for producing bischlorosulfonylimide according to another aspect of the present invention comprises the steps of reacting chlorosulfonyl isocyanate with chlorosulfonic acid; and the step of adding a chlorinating reagent to the resultant product of the reaction.

[0042] Here, the result of the reaction contains at least one of the impurity H2O5NClS2 represented by the following chemical formula (IIa) and the impurity H3O6NS2 represented by the following chemical formula (IIIa), and the step of adding the chlorinating reagent may be a step of removing the impurity contained in the result of the reaction.

[0043]

[0044] …chemical formula (IIa)

[0045] …chemical formula (IIIa)

[0046] Here, as a result of removing the impurities, H2O5NClS2 remaining in the bischlorosulfonylimide may be 10,000 ppm or less and H3O6NS2 may be 10,000 ppm or less, respectively.

[0047] Here, as a result of removing the impurities, H2O5NClS2 remaining in the bischlorosulfonylimide may be 7,100 ppm or less and H3O6NS2 may be 6,700 ppm or less, respectively.

[0048] Here, the chlorinating reagent may be at least one selected from SOCl2, SO2Cl2, COCl2, C2O2Cl2, POCl3, PCl5, SbCl3, ClSO2NCO, SO2(NCO)2, SiCl4, ICl, ICl3, S2Cl2, SCl2, PCl3, COCl2, C6H5CCl3.

[0049] A method for producing a fluorosulfonylimide salt represented by chemical formula (Ia) according to another aspect of the present invention comprises the steps of: reacting chlorosulfonyl isocyanate and chlorosulfonic acid to obtain bischlorosulfonylimide containing at least one of impurities H2O5NClS2 and H3O6NS2; adding a chlorinating reagent to the bischlorosulfonylimide to remove the impurity; and adding butyl acetate to a fluorine compound, stirring the mixture, and then adding bischlorosulfonylimide from which the impurity has been removed.

[0050] …chemical formula (Ia)

[0051] (However, in the chemical formula (Ia), M1 is one of NH4, Li, Na, K, Ca, Mg, Zn, Sb, Rb, and Cs, and A1 is a fluorine atom)

[0052] According to another aspect of the present invention, a method for producing a bisfluorosulfonylimide salt comprises the steps of: reacting chlorosulfonyl isocyanate and chlorosulfonic acid to obtain bischlorosulfonylimide containing at least one of H2O5NClS2 represented by the following chemical formula (IIa) as an impurity and H3O6NS2 represented by the following chemical formula (IIIa); adding a chlorinating reagent to the bischlorosulfonylimide to remove the impurity; obtaining a bisfluorosulfonylimide ammonium salt from the bischlorosulfonylimide from which the impurity has been removed; and obtaining a bisfluorosulfonylimide salt represented by the following chemical formula (Ib) from the obtained bisfluorosulfonylimide ammonium.

[0053] …chemical formula (IIa)

[0054] …chemical formula (IIIa)

[0055] …chemical formula (Ib)

[0056] (However, in the chemical formula (Ib), M2 is one of Li, Na, K, Ca, Mg, Zn, Sb, Rb and Cs,

[0057] A1 is a fluorine atom)

[0058] Here, the obtained bisfluorosulfonylimide salt is an impurity [NS2O5F] represented by the following chemical formula (IIb). 2- and an impurity [NS2O6] represented by the following chemical formula (IIIb). 3- Containing at least one of the above [NS2O5F] 2- is less than 10,000 ppm and the above [NS2O6] 3- may be less than 10,000 ppm.

[0059] …chemical formula (IIb)

[0060] …chemical formula (IIIb)

[0061] Here, the above [NS2O5F] 2- is less than 7,100 ppm and the above [NS2O6] 3- may be less than 6,700 ppm.

[0062] Here, the bisfluorosulfonylimide salt may have a pH of 6 or more and 9 or less in an aqueous solution state.

[0063] Here, the chlorinating reagent may be at least one selected from SOCl2, SO2Cl2, COCl2, C2O2Cl2, POCl3, PCl5, SbCl3, ClSO2NCO, SO2(NCO)2, SiCl4, ICl, ICl3, S2Cl2, SCl2, PCl3, COCl2, C6H5CCl3.

[0064] The fluorosulfonylimide salt according to the present invention can reduce corrosion of the electrolyte, additive, and current collector.

[0065] In addition, the present invention can reduce impurities in bischlorosulfonylimide and bisfluorosulfonylimide, which are intermediate materials for producing bisfluorosulfonylimide.

[0066] The present invention is susceptible to various modifications and embodiments. Specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention. In describing the present invention, detailed descriptions of related known technologies will be omitted if they are deemed to obscure the gist of the present invention.

[0067] Terms such as first, second, etc. may be used to describe various components, but these components should not be limited by these terms. These terms are used solely to distinguish one component from another.

[0068] The terminology used in this application is only used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, it should be understood that the terms "comprise" or "have" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof. Hereinafter, embodiments of the present invention will be described in detail.

[0069] A method for preparing bischlorosulfonylimide according to one embodiment of the present invention is characterized by including a step of adding a chlorinating reagent. More specifically, at least one of impurity 1a and impurity 2a generated in the step of preparing bischlorosulfonylimide as in the following reaction formula (I) is removed by the chlorinating reagent. However, 'removal' herein may mean removing so as to leave only a trace amount that cannot be observed by a measuring device. For example, it may mean leaving 1 ppm or less, 3 ppm or less, 10 ppm or less, or 100 ppm or less. On the other hand, 'removal' may mean removing so as to leave only a trace amount that can minimize a negative effect that may occur in a secondary battery. For example, it could mean leaving it at 1000ppm or less, 3000ppm or less, 5000ppm or less, or 10000ppm or less.

[0070] The step of removing by a chlorinating reagent can be carried out by the following reaction formula (IIa) and the following reaction formula (IIb).

[0071]

[0072] …reaction formula (I)

[0073]

[0074] ...Reaction formula (IIa)

[0075]

[0076] ...reaction formula (IIb)

[0077] Fluorosulfonylimide salts are used in electrolytes, a key component of secondary batteries, and have the advantage of a higher decomposition temperature than LiPF6, the conventionally used commercial electrolyte. A representative fluorosulfonylimide salt is lithium bis(fluorosulfonyl)imide, represented by chemical formula (IV).

[0078] …chemical formula (IV)

[0079] The conventional process for producing fluorosulfonylimide salts largely comprises three process steps. Step 1 may be a process for producing chlorosulfonylimide from raw materials, step 2 may be a process for replacing chlorine with fluorine by adding ammonium fluoride, and step 3 may be a process for replacing ammonium ions with alkali metal ions.

[0080] [Step 1 Process]

[0081] The first step process may be a process described in Scheme (I) for producing chlorosulfonylimide from raw materials. Here, the raw materials may be chlorosulfonyl isocyanate and chlorosulfonic acid.

[0082]

[0083] …reaction formula (I)

[0084] Here, at least one of H2O5NClS2 represented by the following chemical formula (IIa) and H3O6NS2 represented by the following chemical formula (IIIa) may be generated as impurities. The H2O5NClS2 and the H3O6NS2 generated as impurities may be each or the sum of 10,000 ppm or more.

[0085] …chemical formula (IIa)

[0086] …chemical formula (IIIa)

[0087] The second step process may be a step of adding ammonium fluoride (NH4F) to the output of the first step process and reacting it. More specifically, the step may include a step of mixing ammonium fluoride and a solvent and then introducing the output of the first step process. Here, the solvent may preferably be one or more selected from toluene, haloalkane solvents, nitrile solvents, ether solvents, alcohol solvents, ester solvents, carbonate solvents, etc. The solvent may specifically be dimethoxyethane, ethyl acetate, butyl acetate, toluene, chloroform, dichloromethane, dichloroethane, tetrahydrofuran, acetonitrile, etc. In addition, after the step of reacting ammonium fluoride and the output of the first step process is completed, the step may further include a step of recrystallizing the output of the second step process by introducing a non-polar solvent. The output of the above step 1 process may be bischlorosulfonylimide containing the above impurities, and the output of the above step 2 process may be an ammonium salt of bisfluorosulfonylimide.

[0088] The output of the step 1 process may contain at least one of the impurities H2O5NClS2 and H3O6NS2. The impurity is HO5NFS2 expressed by the following chemical formula (1b) as shown in the following reaction formula (III) due to the step 2 process. - , H2O6NS2 expressed by the following chemical formula (2b) - , O5NFS2 expressed by the following chemical formula (3b) 2- and O6NS2 represented by the following chemical formula (4b) 3-At least one of them can be converted. More specifically, Impurity 1a represented by Chemical Formula (IIa) can react with ammonium fluoride in a two-step process to form Impurity 1b and Impurity 3b. Similarly, Impurity 2a represented by Chemical Formula (IIIa) can react with ammonium fluoride in a two-step process to form Impurity 2b and Impurity 4b.

[0089]

[0090] … Reaction formula (III)

[0091]

[0092] …chemical formula (IIb)

[0093]

[0094] …chemical formula (IIIb)

[0095] The third step process may be a step of adding a metal compound to the output of the second step process and reacting the same. Here, the metal compound may be a hydroxide. More specifically, the step may include mixing the hydroxide of the metal compound with a solvent and then introducing the output of the second step process. In the metal compound, the metal may be Li, Na, K, Ca, Mg, Zn, Sb, Rb, or Cs. Here, the solvent may be preferably one or two or more selected from toluene, haloalkane-based, nitrile-based, ether-based, alcohol-based, ester-based, and carbonate-based solvents. Specific examples of the solvent include isopropyl ether, dimethoxyethane, ethyl acetate, butyl acetate, toluene, chloroform, dichloromethane, dichloroethane, tetrahydrofuran, and acetonitrile. Here, NH3 gas is generated as the reaction progresses, and the completion of the reaction can be determined by the cessation of NH3 gas generation. Furthermore, after the step of adding a metal compound to the product of the second step process and reacting it, a step of recrystallizing by adding a non-polar solvent, EDC, may be further included.

[0096] The impurities 1b, 2b, 3b, and 4b included in the output of the above two-step process can participate in the reaction as shown in the following reaction formula (IV) in the three-step process to produce impurity 1c (Impurity 1c), impurity 2c (impurity 2c), impurity 3c (Impurity 3c), impurity 4c (Impurity 4c), and impurity 5c (Impurity 5c).

[0097]

[0098] … Reaction formula (IV)

[0099] (However, in the above reaction formula (IV), M2 is one selected from Li, Na, K, Ca, Mg, Zn, Sb, Rb, and Cs)

[0100] To summarize the contents of the above step 1 to step 3 processes, in manufacturing a bisfluorosulfonylimide salt, impurities generated in the step 1 process participate in reactions in the steps 2 and 3 processes, respectively, and can ultimately form at least one of impurity 1c, impurity 2c, impurity 3c, impurity 4c, and impurity 5c remaining in the bisfluorosulfonylimide salt.

[0101] When a bisfluorosulfonylimide salt containing at least one of the above impurities 1c, 2c, 3c, 4c, and 5c is added as a salt of the electrolyte of a lithium secondary battery, hydrogen ions are released instead of hydrogen metal ions by the sulfonic acid group (-SO3H), as shown in the following reaction formulas (V) and (VI), which may cause the following problems. First, the electrolyte and electrolyte additives may be decomposed. In lithium secondary batteries, the electrolyte is mainly an organic solvent such as ethylene carbonate, and the additive is mainly an organic substance such as fluoroethylene carbonate. These organic substances are vulnerable to acid, and when the temperature rises due to charge and discharge of the battery, they are more likely to react with acid and be easily decomposed. Second, the positive and negative current collectors may be corroded. The hydrogen ions released from the sulfonic acid group may directly react with the positive and negative current collectors, causing corrosion, and hydrogen gas may be generated, which may cause the battery to inflate. In addition, sulfonate (-SO3M) acts to reduce the efficiency of the battery by decomposing the electrolyte and additives, just like moisture in the battery, and the hydrofluoric acid, a byproduct that may be generated at this time, can cause a phenomenon that reduces the lifespan of the battery by corroding the positive and negative current collectors.

[0102] <Step 1 Method>

[0103] A method for producing bischlorosulfonylimide according to one embodiment of the present invention may include a step of reacting chlorosulfonyl isocyanate (OCNSO2Cl) with chlorosulfonic acid (ClSO3H); and a step of adding a chlorinating reagent to the resultant of the reaction.

[0104] At this time, the reaction temperature of the step of reacting the chlorosulfonyl isocyanate (OCNSO2Cl) and chlorosulfonic acid (ClSO3H) may be 100°C or more and less than 150°C. Preferably, the reaction temperature may be 125°C or more and less than 135°C. The step of reacting the chlorosulfonyl isocyanate and chlorosulfonic acid may proceed until the generation of carbon dioxide gas stops. This is because, since carbon dioxide gas is generated in the step of reacting the chlorosulfonyl isocyanate and chlorosulfonic acid, the reaction may be considered completed when the generation of carbon dioxide gas stops.

[0105] When chlorosulfonyl isocyanate and chlorosulfonic acid are reacted, at least one of impurity 1a (Impurity 1a) and impurity 2a (Impurity 2a) described in the reaction formula (I) may be generated in addition to bischlorosulfonylimide. Impurity 1a may be H2O5NClS2 represented by the following chemical formula (IIa), and impurity 2a may be H3O6NS2 represented by the following chemical formula (IIIa). The H2O5NClS2 and H3O6NS2 generated as impurities may be 10,000 ppm or more, individually or in combination.

[0106] …chemical formula (IIa)

[0107] …chemical formula (IIIa)

[0108] <Step 1 Method>

[0109] Here, the step of adding the chlorinating reagent may be a step of removing H2O5NClS2 represented by the chemical formula (IIa) and H3O6NS2 represented by the chemical formula (IIIa), which are impurities included in the result of the reaction.

[0110] The amount of the chlorinating reagent added may be determined by the amount of the chlorosulfonyl isocyanate administered. More specifically, the amount of the chlorinating reagent added may be 1 / 8 to 1 / 20 of the number of molecules of chlorosulfonyl isocyanate, based on the number of molecules. Preferably, it may be 1 / 9 to 1 / 15, and even more preferably, it may be 1 / 10.

[0111] In the step of adding the above chlorination reagent, the reason for adding the above chlorination reagent is explained with reference to the following reaction formulas (I), (IIa), and (IIb).

[0112]

[0113] …reaction formula (I)

[0114]

[0115] …reaction formula (IIa)

[0116]

[0117] …reaction formula (IIb)

[0118] Reaction formula (I) is not written in a stoichiometric ratio, but rather to show that impurity 1 and impurity 2 are produced as reaction products. Similarly, reaction formulas (IIa) and (IIb) are not written in a stoichiometric ratio, but rather to show that impurity 1 and impurity 2 are removed as a result of adding a chlorinating reagent.

[0119] The above H2O5NClS2 and the H3O6NS2 can be at least partially removed by a chlorinating reagent. The chlorinating reagent can be at least one selected from SOCl2, SO2Cl2COCl2, C2O2Cl2, POCl3, PCl5, SbCl3, ClSO2NCO, SO2(NCO)2, SiCl4, ICl, ICl3, S2Cl2, SCl2, PCl3, COCl2, C6H5CCl3. When a chlorination reaction occurs due to the addition of a chlorinating reagent, the sulfonic acid group (-SO3H) of the H2O5NClS2 and the H3O6NS2 is converted into a chlorosulfonyl group (-SO2Cl), and the H2O5NClS2 and the H3O6NS2 can be converted into bischlorosulfonylimide.

[0120] <Step 1 Method>

[0121] According to one embodiment of the present invention, the method for producing bischlorosulfonylimide may be characterized in that the H2O5NClS2 and H3O6NS2 remaining in the bischlorosulfonylimide as a result of removing the H2O5NClS2 and H3O6NS2 are each 10,000 ppm or less. In addition, the remaining H2O5NClS2 and H3O6NS2 may be 7,100 ppm and 6,700 ppm or less, respectively. In addition, the remaining H2O5NClS2 and H3O6NS2 may be 6,300 ppm and 5,200 ppm or less, respectively. In addition, the remaining H2O5NClS2 and H3O6NS2 may be 289 ppm and 325 ppm or less, respectively. Additionally, the remaining H2O5NClS2 and H3O6NS2 may be less than 187 ppm and 124 ppm, respectively.

[0122] <2-step method>

[0123] According to another aspect of the present invention, there is provided a method for producing a fluorosulfonylimide salt represented by chemical formula (Ia), the method comprising: reacting chlorosulfonyl isocyanate and chlorosulfonic acid to obtain bischlorosulfonylimide containing at least one of impurities H2O5NClS2 and H3O6NS2; adding a chlorinating reagent to the bischlorosulfonylimide to remove the impurity; and adding butyl acetate to a fluorine compound, stirring the mixture, and then adding bischlorosulfonylimide from which the impurity has been removed.

[0124] …chemical formula (Ia)

[0125] Here, A1 can be a fluorine atom.

[0126] Here, the chlorinating reagent may be at least one selected from SOCl2, SO2Cl2, COCl2, C2O2Cl2, POCl3, PCl5, SbCl3, ClSO2NCO, SO2(NCO)2, SiCl4, ICl, ICl3, S2Cl2, SCl2, PCl3, COCl2, C6H5CCl3.

[0127] In addition, the fluorine compound may be any one selected from among HF, NH4F, LiF, NaF, KF, CaF2, MgF2, ZnF2, SbF3, RbF, and CsF. Accordingly, M1 of the chemical formula (Ia) may be any one of H, NH4, Li, Na, K, Ca, Mg, Zn, Sb, Rb, and Cs.

[0128] However, for the convenience of explanation, the above A1 is a fluorine atom and the fluorine compound is ammonium fluoride (NH4F), and the fluorosulfonylimide salt produced accordingly will be bisfluorosulfonylimide ammonium.

[0129] When the impurities are removed by adding a chlorinating reagent to the above bischlorosulfonylimide, the impurities remaining in the finally produced bisfluorosulfonylimide ammonium will also decrease.

[0130] The step of adding butyl acetate to the ammonium fluoride and stirring can be performed by cooling to -5°C or lower. In addition, the stirring step can be performed using a magnetic stirrer.

[0131] The step of adding bischlorosulfonylimide from which the above impurities have been removed may be performed for 40 minutes to 80 minutes while maintaining a temperature of 0°C to 15°C. This is because an exothermic reaction occurs as bischlorosulfonylimide is added.

[0132] After the above exothermic reaction is completed, the temperature can be raised to 60°C or higher and 100°C or lower and the reaction can be carried out for 4 hours or higher and 6 hours or lower.

[0133] After the above temperature-raising reaction is completed, a step may be included of cooling to a temperature of 15°C or higher and 35°C or lower, filtering to remove solid impurities, concentrating the filtrate, and then recrystallizing by adding toluene, a non-polar solvent.

[0134] As presented through the above reaction formula (III), the impurities remaining in the product of the first step process, H2O5NClS2 and H3O6NS2, are converted to HO5NFS2 expressed by the following chemical formula (1b) as shown in the following reaction formula (III) through the second step process. - , H2O6NS2 expressed by the following chemical formula (2b) - , O5NFS2 expressed by the following chemical formula (3b) 2- and O6NS2 represented by the following chemical formula (4b) 3-At least one of them can be converted. More specifically, Impurity 1a represented by Chemical Formula (IIa) can react with ammonium fluoride in a two-step process to form Impurity 1b and Impurity 3b. Similarly, Impurity 2a represented by Chemical Formula (IIIa) can react with ammonium fluoride in a two-step process to form Impurity 2b and Impurity 4b.

[0135] The sum of Impurity 1b and Impurity 3b may be 10,000 ppm or less, 7,100 ppm or less, 6,300 ppm or less, 289 ppm or less, or 187 ppm or less. In this case, the sum of Impurity 1b and Impurity 3b is [NS2O5F] 2- can be measured in the form of

[0136] In addition, the sum of Impurity 2b and Impurity 4b may be 10,000 ppm or less, 6,700 ppm or less, 5,200 ppm or less, 325 ppm or less, or 124 ppm or less. In this case, the sum of Impurity 2b and Impurity 4b is [NS2O6] 3- can be measured in the form of

[0137] <3-step method>

[0138] According to another aspect of the present invention, a method for producing a bisfluorosulfonylimide salt may include the steps of: reacting chlorosulfonyl isocyanate and chlorosulfonic acid to obtain bischlorosulfonylimide containing at least one of H2O5NClS2 represented by the following chemical formula (IIa) as an impurity and H3O6NS2 represented by the following chemical formula (IIIa); adding a chlorinating reagent to the bischlorosulfonylimide to remove the impurity; obtaining a bisfluorosulfonylimide ammonium salt from the bischlorosulfonylimide from which the impurity has been removed; and obtaining a bisfluorosulfonylimide salt represented by the following chemical formula (Ib) from the obtained bisfluorosulfonylimide ammonium.

[0139] …chemical formula (IIa)

[0140] …chemical formula (IIIa)

[0141] …chemical formula (Ib)

[0142] Here, A1 can be a fluorine atom.

[0143] M2 of the above chemical formula (Ib) may be any one of NH4, Li, Na, K, Ca, Mg, Zn, Sb, Rb, and Cs.

[0144] Here, the chlorinating reagent may be at least one selected from SOCl2, SO2Cl2, COCl2, C2O2Cl2, POCl3, PCl5, SbCl3, ClSO2NCO, SO2(NCO)2, SiCl4, ICl, ICl3, S2Cl2, SCl2, PCl3, COCl2, C6H5CCl3. However, for the convenience of explanation, the above A1 will be described as an example in which it is a fluorine atom and the above M2 is Li. Accordingly, the above bisfluorosulfonylimide salt will be described below in the example in which it is a bisfluorosulfonylimide lithium salt.

[0145] The reaction temperature of the step of reacting the chlorosulfonyl isocyanate (OCNSO2Cl) and chlorosulfonic acid (ClSO3H) may be 100°C or more and less than 150°C. Preferably, the reaction temperature may be 125°C or more and less than 135°C. The step of reacting the chlorosulfonyl isocyanate and chlorosulfonic acid may proceed until the generation of carbon dioxide gas stops. This is because, since carbon dioxide gas is generated in the step of reacting the chlorosulfonyl isocyanate and chlorosulfonic acid, the reaction may be considered completed when the generation of carbon dioxide gas stops.

[0146] When chlorosulfonyl isocyanate and chlorosulfonic acid are reacted, at least one of impurity 1a (Impurity 1a) and impurity 2a (Impurity 2a) described in the above reaction formula (I) may be generated in addition to bischlorosulfonylimide. Impurity 1a may be H2O5NClS2 represented by the above chemical formula (IIa), and impurity 2a may be H3O6NS2 represented by the above chemical formula (IIIa). The H2O5NClS2 and the H3O6NS2 generated as impurities may be 10,000 ppm or more, individually or in combination.

[0147] When a chlorination reaction occurs due to the addition of a chlorinating reagent, the sulfonic acid group (-SO3H) of the H2O5NClS2 and the H3O6NS2 is converted into a chlorosulfonyl group (-SO2Cl), and the H2O5NClS2 and the H3O6NS2 can be converted into bischlorosulfonylimide.

[0148] When the impurities are removed by adding a chlorinating reagent to the bischlorosulfonylimide, the impurities remaining in the bisfluorosulfonylimide lithium salt finally produced will also be reduced.

[0149] The impurities 1b, 2b, 3b, and 4b included in the step of obtaining the bisfluorosulfonylimide ammonium salt can participate in the reaction as shown in the following reaction formula (IV) in the step of obtaining the bisfluorosulfonylimide lithium salt from the bisfluorosulfonylimide ammonium salt to produce impurity 1c (Impurity 1c), impurity 2c (impurity 2c), impurity 3c (Impurity 3c), impurity 4c (Impurity 4c), and impurity 5c (Impurity 5c).

[0150]

[0151] … Reaction formula (IV)

[0152] The sum of Impurity 1c and Impurity 3c may be 10,000 ppm or less, 7,100 ppm or less, 6,300 ppm or less, 289 ppm or less, or 187 ppm or less. In this case, the sum of Impurity 1c and Impurity 3c is [NS2O5F] 2- can be measured in the form of

[0153] In addition, the sum of Impurity 2C, Impurity 4C, and Impurity 5C may be 10,000 ppm or less, 6,700 ppm or less, 5,200 ppm or less, 325 ppm or less, and 124 ppm or less. In this case, the sum of Impurity 2C, Impurity 4C, and Impurity 5C is [NS2O6] 3- can be measured in the form of

[0154] <Stage 1 Item>

[0155] According to one aspect of the present invention, the present invention relates to bischlorosulfonylimide containing at least one of an impurity H2O5NClS2 represented by the following chemical formula (IIa) in an amount of 10,000 ppm or less and an impurity H3O6NS2 represented by the following chemical formula (IIIa) in an amount of 10,000 ppm or less.

[0156] …chemical formula (IIa)

[0157] …chemical formula (IIIa)

[0158] Here, by adding a chlorinating reagent in the above bischlorosulfonylimide manufacturing process, the H2O5NClS2 may be 10,000 ppm or less and the H3O6NS2 may be 10,000 ppm or less.

[0159] Here, the chlorinating reagent may be selected from SOCl2, SO2Cl2COCl2, C2O2Cl2, POCl3, PCl5, SbCl3, ClSO2NCO, SO2(NCO)2, SiCl4, ICl, ICl3, S2Cl2, SCl2, PCl3, COCl2, C6H5CCl3.

[0160] According to the conventional method for producing bischlorosulfonylimide, at least one of the impurities represented by the chemical formula (IIa) and the impurities represented by the chemical formula (IIIa) is contained. When bischlorosulfonylimide containing the impurities is applied to the above-described 2-3 step processes, the impurities continuously participate in the reaction, thereby lowering the purity of the final product, the fluorosulfonylimide salt. Therefore, after completing the 1st step process, the impurities are removed by a chlorinating reagent, so that the purity of the final product, the fluorosulfonylimide salt, can be improved.

[0161] That is, when the bischlorosulfonylimide contains more than 10,000 ppm of at least one of H2O5NClS2 represented by the chemical formula (IIa) and H3O6NS2 represented by the chemical formula (IIIa), the result of the subsequent process may be adversely affected, resulting in a reduced yield and inclusion of acidic impurities. The content of the impurity is preferably 10,000 ppm or less, and the lower limit of the impurity may be about 1 ppm.

[0162] <Step 2 Items>

[0163] According to another aspect of the present invention, the present invention provides an impurity [NS2O5F] represented by the following chemical formula (IIb) 2- and an impurity [NS2O6] represented by the following chemical formula (IIIb). 3- Containing at least one of [NS2O5F], wherein the chlorinating reagent is added during the manufacturing process. 2- is less than 10,000ppm and the above [NS2O6] 3- A fluorosulfonylimide represented by the chemical formula (Ia) having a concentration of 10,000 ppm or less can be provided.

[0164] …chemical formula (Ia)

[0165] …chemical formula (IIb)

[0166] …chemical formula (IIIb)

[0167] Here, M1 is H, and A1 is a fluorine atom or an alkyl group having 1 to 6 carbon atoms in which one or more hydrogen atoms are replaced with a fluorine atom.

[0168] Also, the above [NS2O5F] 2- is less than 7,100 ppm, and the above [NS2O6] 3- may be less than 6,700 ppm.

[0169] In addition, the chlorinating reagent added above may be selected from SOCl2, SO2Cl2COCl2, C2O2Cl2, POCl3, PCl5, SbCl3, ClSO2NCO, SO2(NCO)2, SiCl4, ICl, ICl3, S2Cl2, SCl2, PCl3, COCl2, C6H5CCl3.

[0170] According to another embodiment of the present invention, the present invention provides an impurity [NS2O5F] represented by the following chemical formula (IIb) 2- and an impurity [NS2O6] represented by the following chemical formula (IIIb). 3- Containing at least one of [NS2O5F], wherein the chlorinating reagent is added during the manufacturing process. 2- is less than 10,000ppm and the above [NS2O6] 3- A fluorosulfonylimide salt represented by chemical formula (Ia) having a concentration of 10,000 ppm or less can be provided.

[0171] …chemical formula (Ia)

[0172] …chemical formula (IIb)

[0173] …chemical formula (IIIb)

[0174]

[0175] Here, A1 is a fluorine atom or an alkyl group having 1 to 6 carbon atoms in which one or more hydrogen atoms are replaced with fluorine atoms, and M1 is one of NH4, Li, Na, K, Ca, Mg, Zn, Sb, Rb, and Cs.

[0176] Also, the above [NS2O5F] 2- is less than 7,100 ppm, and the above [NS2O6] 3- may be less than 6,700 ppm.

[0177] In addition, the chlorinating reagent added above may be selected from SOCl2, SO2Cl2COCl2, C2O2Cl2, POCl3, PCl5, SbCl3, ClSO2NCO, SO2(NCO)2, SiCl4, ICl, ICl3, S2Cl2, SCl2, PCl3, COCl2, C6H5CCl3.

[0178] <3-step item>

[0179] Impurity [NS2O5F] represented by the following chemical formula (IIb) 2- and an impurity [NS2O6] represented by the following chemical formula (IIIb). 3- Containing at least one of the above [NS2O5F] 2- is less than 10,000 ppm and the above [NS2O6] 3- Fluorosulfonylimide salt represented by chemical formula (Ib) having a concentration of 10,000 ppm or less.

[0180] …chemical formula (Ib)

[0181] …chemical formula (IIb)

[0182] …chemical formula (IIIb)

[0183] Here, also, the above M2 is one of Li, Na, K, Ca, Mg, Zn, Sb, Rb and Cs.

[0184] In the above chemical formula (Ib), A1 represents a fluorine atom or a hydrocarbon group having 1 to 6 carbon atoms in which one or more hydrogen atoms are replaced with fluorine atoms. The hydrocarbon group is preferably a straight-chain fluoroalkyl group having 1 to 6 carbon atoms. Examples thereof include a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a fluoroethyl group, a difluoroethyl group, a trifluoroethyl group, and a pentafluoroethyl group. Among these, a fluorine atom, a trifluoromethyl group, and a pentafluoroethyl group are preferable as A1. The bisfluorosulfonyl imide or N-(fluorosulfonyl)-N-(fluoroalkylsulfonyl)imide salt of the present invention is suitable as an ion conductive material for various electrochemical devices. In particular, lithium fluorosulfonyl imide whose cation is lithium is useful as an electrolyte or ionic liquid used in lithium secondary batteries, capacitors, etc., or as an intermediate of a fluorosulfonyl compound.

[0185] Here, the above [NS2O5F] 2- It can be 7,100 ppm or less, 6,300 ppm or less, 289 ppm or less, or 187 ppm or less. In addition, [NS2O6] 3- It can be 6,700ppm or less, 5,200ppm or less, 325ppm or less, or 124ppm or less.

[0186] Here, the fluorosulfonylimide alkali metal salt may have a pH of 6 or more and 9 or less in an aqueous solution state. According to another embodiment, the pH may be 6.9 or more and 7.1 or less.

[0187] Here, when the fluorosulfonylimide salt is a fluorosulfonylimide alkali metal salt, an impurity [NS2O5F] expressed by chemical formula (IIb) 2- and an impurity [NS2O6] represented by the following chemical formula (IIIb). 3- Since the content of the fluorosulfonylimide alkali metal salt is suppressed, the fluorosulfonylimide alkali metal salt may not be acidic in an aqueous solution.

[0188] <Electrolyte containing 3-stage material>

[0189] According to another aspect of the present invention, the present invention may include an electrolyte comprising a fluorosulfonylimide salt. For example, the fluorosulfonylimide salt may be lithium bisfluorosulfonylimide. The fluorosulfonylimide salt may be [NS2O5F]. 2- The content of [NS2O6] is 7100 ppm or less, and 3- The content may be less than 6700 ppm.

[0190] The above impurity [NS2O5F] 2- The content of and the above [NS2O6] 3- The content of can be measured by ion chromatography. Ion chromatography is for evaluating the types and contents of anions and cations, and [NS2O5F] that can be ionized 2- and the above [NS2O6] 3- It may be suitable for measuring the presence and content of .

[0191] <Electrochemical devices (batteries, etc.) containing step 4 objects>

[0192] According to another aspect of the present invention, the present invention may be an electrochemical device comprising the electrolyte.

[0193] An electrochemical device to which an electrolyte according to the present invention is applied, for example, a lithium secondary battery, comprises the impurity [NS2O5F] 2- and the above [NS2O6] 3- As the content of the electrolyte and additives is reduced, decomposition of the electrolyte and additives is prevented, and corrosion of the current collector can be prevented.

[0194] Below, the excellence and originality of the present invention will be explained through specific examples and comparative examples. However, it should be understood that the present invention is not limited to the examples presented below.

[0195] [Experimental Example]

[0196] [Example 1]

[0197] (Step 1 reaction) 25.8 g of chlorosulfonic acid (ClSO3H) was slowly added to 30 g of chlorosulfonyl isocyanate (OCNSO2Cl), and stirred with a magnetic stirrer. The stirred solution was heated from room temperature to 130 ℃ and reacted for 20 hours. At this time, the progress of the reaction can be determined by whether or not CO2 gas is generated. Specifically, the reaction can be judged to be complete when CO2 gas is no longer generated. Next, 2.52 g of thionyl chloride (SOCl2) was added and the reaction was sufficiently performed until no more SO2 gas was generated. After the reaction was completed, 44.92 g of bischlorosulfonylimide (HCSI) as a yellow liquid was obtained. (Yield 99%)

[0198] (Step 2 reaction) 120 g of butyl acetate was added to 20.76 g of ammonium fluoride (NH4F), cooled to below -5°C, and stirred with a magnetic stirrer. Next, 30 g of bischlorosulfonylimide (HCSI) obtained in the previous step 1 reaction was slowly added dropwise. As heat was generated during this process, the reaction was stirred at 15°C for about 1 hour to ensure a stable reaction. After the exotherm was complete, the reaction temperature was increased to 80°C at a heating rate of 1°C / 1 min and reacted for 5 hours. After the reaction was complete, it was cooled to 25°C and filtered to remove solid impurities. The filtrate was concentrated and recrystallized by adding 90 g of a non-polar solvent, toluene. As a result of recrystallization, 23.05 g of bisfluorosulfonylimide ammonium salt (NH4FSI) as a white crystalline solid was obtained (yield 83%).

[0199] (Step 3 reaction) 30 g of isopropyl ether was added to 20 g of bisfluorosulfonylimide ammonium salt (NH4FSI) obtained in the previous step 2 reaction and stirred with a magnetic stirrer at 25℃. Next, 5.08 g of lithium hydroxide (LiOH H2O) was added and reacted at room temperature for 3 hours. When the generation of NH3 gas stops, the reaction can be considered complete. After the reaction is complete, it is cooled to room temperature and filtered to remove solid impurities. The filtrate is concentrated and then recrystallized by adding a non-polar solvent, 1,2-dichloroethane (EDC). As a result of recrystallization, 17.18 g of lithium bisfluorosulfonylimide (LiFSI) as a white crystalline solid was obtained (yield 91%).

[0200] (Measurement) The purity, impurity type, and impurity content of lithium bisfluorosulfonyl imide obtained in the 3-step reaction of Example 1 were measured using ion chromatography.

[0201] [Example 2]

[0202] (Step 1 reaction) 25.8 g of chlorosulfonic acid (ClSO3H) was slowly added to 30 g of chlorosulfonyl isocyanate (OCNSO2Cl), and the mixture was stirred with a magnetic stirrer. The reaction temperature was increased from room temperature to 130 ℃ and the mixture was reacted for 20 hours. The reaction was allowed to proceed until CO2 gas was no longer generated. Then, 2.09 g of phosgene (COCl2) was added and the mixture was allowed to react sufficiently until CO2 gas was no longer generated. After the reaction was completed, 44.90 g of bischlorosulfonylimide (HCSI) as a yellow liquid was obtained (yield 99%).

[0203] (2nd step reaction) In the same manner as the 2nd step reaction of Example 1, the bischlorosulfonylimide obtained in the 1st step reaction was reacted to produce bisfluorosulfonylimide ammonium salt (yield 83%).

[0204] (Step 3 reaction) In the same manner as the step 3 reaction of Example 1, the bisfluorosulfonylimide ammonium salt obtained in the step 2 reaction was reacted to produce lithium bisfluorosulfonylimide (yield 92%).

[0205] (Measurement) The purity, impurity type, and impurity content of lithium bisfluorosulfonyl imide obtained in the 3-step reaction of Example 2 were measured using ion chromatography.

[0206] [Example 3]

[0207] (Step 1 reaction) 25.8 g of chlorosulfonic acid (ClSO3H) was slowly added to 30 g of chlorosulfonyl isocyanate (OCNSO2Cl), and stirred with a magnetic stirrer. The reaction temperature was increased from room temperature to 130 ℃ and reacted for 20 hours. The reaction was allowed to proceed until CO2 gas was no longer generated. Then, 2.86 g of sulfuryl chloride (SO2Cl2) was added and the reaction was allowed to proceed sufficiently until SO3 gas was no longer generated. After the reaction was completed, 44.45 g of bischlorosulfonylimide (HCSI) as a yellow liquid was obtained (yield 98%).

[0208] (Step 2 reaction) In the same manner as the step 2 reaction of Example 1, the bischlorosulfonylimide obtained in the step 1 reaction was reacted to produce bisfluorosulfonylimide ammonium salt (yield: 85%).

[0209] (Step 3 reaction) In the same manner as the step 3 reaction of Example 1, the bisfluorosulfonylimide ammonium salt obtained in the step 2 reaction was reacted to produce lithium bisfluorosulfonylimide (yield 92%).

[0210] (Measurement) The purity, impurity type, and impurity content of lithium bisfluorosulfonyl imide obtained in the 3-step reaction of Example 2 were measured using ion chromatography.

[0211] [Example 4]

[0212] (Step 1 reaction) 25.8 g of chlorosulfonic acid (ClSO3H) was slowly added to 30 g of chlorosulfonyl isocyanate (OCNSO2Cl), and stirred with a magnetic stirrer. The reaction temperature was increased from room temperature to 130 ℃ and reacted for 20 hours. The reaction was allowed to proceed until CO2 gas was no longer generated. Then, 2.69 g of oxalyl chloride (C2O2Cl2) was added and the reaction was allowed to proceed sufficiently until CO2 and CO gases were no longer generated. After the reaction was completed, 44.89 g of bischlorosulfonylimide (HCSI) as a yellow liquid was obtained (yield 99%).

[0213] (2nd step reaction) In the same manner as the 2nd step reaction of Example 1, the bischlorosulfonylimide obtained in the 1st step reaction was reacted to produce bisfluorosulfonylimide ammonium salt (yield 84%).

[0214] (Step 3 reaction) In the same manner as the step 3 reaction of Example 1, the bisfluorosulfonylimide ammonium salt obtained in the step 2 reaction was reacted to produce lithium bisfluorosulfonylimide (yield 93%).

[0215] (Measurement) The purity, impurity type, and impurity content of lithium bisfluorosulfonyl imide obtained in the three-step reaction of Example 3 were measured using ion chromatography.

[0216] [Comparative example]

[0217] (Step 1 reaction) 25.8 g of chlorosulfonic acid (ClSO3H) was slowly added to 30 g of chlorosulfonyl isocyanate (OCNSO2Cl), and stirred with a magnetic stirrer. The reaction temperature was increased from room temperature to 130 ℃, and the mixture was reacted for 24 hours until CO2 gas was no longer generated. After the reaction was completed, 43.09 g of bischlorosulfonylimide (HCSI) as a yellow liquid was obtained (yield 95%).

[0218] (Step 2 reaction) 120 g of butyl acetate was added to 20.76 g of ammonium fluoride (NH4F), cooled to below -5℃, and stirred with a magnetic stirrer. Then, 30 g of bischlorosulfonylimide (HCSI) was slowly added dropwise. As heat was generated during this process, the mixture was stirred at 15℃ for about 1 hour to ensure a stable reaction. After the exotherm was complete, the reaction temperature was raised to 80℃ and the mixture was reacted for 5 hours. After the reaction was completed, it was cooled to 25℃, filtered to remove solid impurities, and the filtrate was concentrated and recrystallized by adding 90 g of toluene, a non-polar solvent. As a result of recrystallization, 20.27 g of bisfluorosulfonylimide ammonium salt (NH4FSI) as a white crystalline solid was obtained (yield 73%).

[0219] (Step 3 reaction) 30 g of isopropyl ether was added to 20 g of bisfluorosulfonylimide ammonium salt (NH4FSI) obtained in the previous step 2 reaction and stirred with a magnetic stirrer at 25℃. Next, 5.08 g of lithium hydroxide hydrate (LiOH H2O) was added and reacted at 25℃ for 3 hours. At this time, the reaction can be considered complete when the generation of NH3 gas stops. After the reaction is complete, it is cooled to 25℃ and filtered to remove solid impurities. The filtrate is concentrated and then recrystallized by adding a non-polar solvent, 1,2-dichloroethane (EDC). As a result of recrystallization, 16.04 g of lithium bisfluorosulfonylimide (LiFSI) as a white crystalline solid was obtained (yield 85%).

[0220] [result]

[0221] The impurity content of the lithium bisfluorosulfonylimide (LiFSI) obtained in Examples 1 to 4 and Comparative Examples was measured using ion chromatography. The measurement results are shown in Table 1 below.

[0222] Chlorination reagent [NS2O5F] 2- [NS2O6] 3-Example 1 SOCl 2 187 ppm 124 ppm Example 2 COCl 2 89 ppm 325 ppm Example 3 SO2Cl 2 7,100 ppm 6,700 ppm Example 4 C2O2Cl 2 6,300 ppm 5,200 ppm Comparative Example Not used 23,000 ppm 15,000 ppm

[0223] Additionally, the purity and pH of lithium bisfluorosulfonyl imide (LiFSI) obtained in Examples 1 to 4 and Comparative Examples were measured. The measurement results are shown in Table 2 below.

[0224] Classification Step 1 Reaction Yield (%) Step 2 Reaction Yield (%) Step 3 Reaction Yield (%) LiFSI Purity (%, based on FSI anion) pH Example 1 998 39 199.57.0 Example 2 998 39 299.67.0 Example 3 98 8 59 299.76.9 Example 4 998 49 399.66.9 Comparative Example 9 57 38 598.45.4

[0225] According to Table 2 above, Examples 1 to 4, in which chlorine substitution was performed using a chlorinating reagent, contained less [NS2O5F], an impurity that can cause corrosion in the battery, than the comparative examples that did not use a chlorinating reagent. 2- and [NS2O6] 3- The content of was suppressed. In addition, the pH measurement result confirmed that it was a neutral state of 6.9 to 7.0. This suggests that the lithium bisfluorosulfonyl imide according to the present invention can suppress corrosion of the battery when applied as a lithium salt of the battery. In addition, it was confirmed that Examples 1 to 4, in which chlorine substitution was performed using a chlorinating reagent, had an increased yield at each reaction stage compared to the comparative example that did not use a chlorinating reagent. According to the examples of the present invention, Examples 1 to 4 showed a high yield of 98 to 99% in the 1-step reaction yield, whereas the comparative example showed a relatively low yield of 95% due to the generation of impurities.

[0226] The two-step reaction yields in Table 2 above are calculated by dividing the number of molecules of bisfluorosulfonylimide ammonium salt produced by the amount of bischlorosulfonylimide introduced in the two-step reaction of each example and comparative example. Examples 1 to 4 showed a two-step reaction yield of 83 to 85%, and Comparative Example 1 showed a two-step reaction yield of 73%. This is presumed to be because impurities hinder the reaction between bischlorosulfonylimide and ammonium fluoride, and generate other impurities while reacting directly with ammonium fluoride.

[0227] The 3-step reaction yield in Table 2 above is calculated by calculating the number of molecules of bisfluorosulfonylimide lithium salt produced relative to the bisfluorosulfonylimide ammonium salt introduced in the 3-step reaction of each example and comparative example. Examples 1 to 4 showed 91 to 93% in the 3-step reaction yield, while the comparative example showed 85% in the 3-step reaction yield. This is presumed to be because the impurities introduced together in the 3rd step in the comparative example hinder the reaction between bisfluorosulfonylimide ammonium salt and lithium hydroxide, and directly react with lithium hydroxide to produce impurities in the final stage.

[0228] Table 2 above shows the purity of the finally produced bisfluorosulfonylimide lithium salt, measured based on fluorosulfonylimide ions. Examples 1 to 4 exhibited high purities of 99.5 to 99.7%, while the comparative example exhibited a relatively low purity of 98.4%. Such low purity may degrade battery performance.

[0229] The above preferred embodiments of the present invention are disclosed for the purpose of illustration, and those skilled in the art with ordinary knowledge of the present invention will be able to make various modifications, changes, and additions within the spirit and scope of the present invention, and such modifications, changes, and additions should be considered to fall within the scope of the following patent claims.

Claims

1. Bischlorosulfonylimide containing at least one of impurity H2O5NClS2 expressed by the following chemical formula (IIa) in an amount of 10,000 ppm or less and impurity H3O6NS2 expressed by the following chemical formula (IIIa) in an amount of 10,000 ppm or less. …chemical formula (IIa) …chemical formula (IIIa) 2. In paragraph 1, Bischlorosulfonylimide characterized in that, by adding a chlorinating reagent in the above bischlorosulfonylimide manufacturing process, the H2O5NClS2 becomes 10,000 ppm or less and the H3O6NS2 becomes 10,000 ppm or less.

3. In paragraph 2, Bischlorosulfonylimide characterized in that the above H2O5NClS2 is 7,100 ppm or less and the above H3O6NS2 is 6,700 ppm or less.

4. In paragraph 2, The above chlorinating reagent is, A bischlorosulfonylimide characterized by at least one selected from SOCl2, SO2Cl2, COCl2, C2O2Cl2, POCl3, PCl5, SbCl3, ClSO2NCO, SO2(NCO)2, SiCl4, ICl, ICl3, S2Cl2, SCl2, PCl3, COCl2, C6H5CCl3.

5. Impurity [NS2O5F] represented by the following chemical formula (IIb) 2- and an impurity [NS2O6] represented by the following chemical formula (IIIb). 3- Containing at least one of [NS2O5F], wherein the chlorinating reagent is added during the manufacturing process. 2- is less than 10,000ppm and the above [NS2O6] 3- Fluorosulfonylimide represented by the chemical formula (Ia) having a concentration of 10,000 ppm or less. …chemical formula (Ia) …chemical formula (IIb) …chemical formula (IIIb) (However, in the above chemical formula (Ia), M1 is H, A1 is a fluorine atom or an alkyl group having 1 to 6 carbon atoms in which one or more hydrogen atoms are replaced by fluorine atoms.

6. In paragraph 5, The above [NS2O5F] 2- is less than 7,100 ppm, and the above [NS2O6] 3- Fluorosulfonylimide characterized by having a content of 6,700 ppm or less.

7. Impurity [NS2O5F] represented by the following chemical formula (IIb) 2- and an impurity [NS2O6] represented by the following chemical formula (IIIb). 3- Containing at least one of [NS2O5F], wherein the chlorinating reagent is added during the manufacturing process. 2- is less than 10,000ppm and the above [NS2O6] 3- Fluorosulfonylimide salt represented by chemical formula (Ia) having a concentration of 10,000 ppm or less. …chemical formula (Ia) …chemical formula (IIb) …chemical formula (IIIb) (However, in the above chemical formula (Ia), M1 is one of NH4, Li, Na, K, Ca, Mg, Zn, Sb, Rb, and Cs, A1 is a fluorine atom or an alkyl group having 1 to 6 carbon atoms in which one or more hydrogen atoms are replaced by fluorine atoms.

8. In paragraph 7, The above [NS2O5F] 2- is less than 7,100 ppm, and the above [NS2O6] 3- Fluorosulfonylimide salt characterized by having a content of 6,700 ppm or less.

9. Impurity [NS2O5F] represented by the following chemical formula (IIb) 2- and an impurity [NS2O6] represented by the following chemical formula (IIIb). 3- Containing at least one of the above [NS2O5F] 2- is less than 10,000 ppm and the above [NS2O6] 3- Fluorosulfonylimide salt represented by chemical formula (Ib) having a concentration of 10,000 ppm or less. …chemical formula (Ib) …chemical formula (IIb) …chemical formula (IIIb) (However, in the above chemical formula (Ib), M2 is one of Li, Na, K, Ca, Mg, Zn, Sb, Rb, and Cs, A1 is a fluorine atom or an alkyl group having 1 to 6 carbon atoms in which one or more hydrogen atoms are replaced by fluorine atoms.

10. In paragraph 9, The above [NS2O5F] 2- is less than 7,100 ppm and the above [NS2O6] 3- Fluorosulfonylimide salt represented by chemical formula (Ib) characterized in that it is 6,700 ppm or less.

11. In paragraph 10, The above [NS2O5F] 2- is less than 6,300 ppm and the above [NS2O6] 3- Fluorosulfonylimide salt represented by chemical formula (Ib) characterized in that the content is 5,200 ppm or less.

12. In paragraph 11, The above [NS2O5F] 2- is less than 289 ppm and the above [NS2O6] 3- A fluorosulfonylimide salt represented by chemical formula (Ib) characterized in that the content is 325 ppm or less.

13. In paragraph 12, The above [NS2O5F] 2- is less than 187 ppm and the above [NS2O6] 3- Fluorosulfonylimide salt represented by chemical formula (Ib) characterized in that it is 124 ppm or less.

14. In paragraph 9, A fluorosulfonylimide salt characterized by a pH of 6 or more and 9 or less in an aqueous solution state.

15. An electrolyte comprising a fluorosulfonylimide or a fluorosulfonylimide salt as described in any one of claims 5 to 14.

16. An electrochemical device comprising the electrolyte described in Article 15.

17. A step of reacting chlorosulfonyl isocyanate and chlorosulfonic acid; and A method for producing bischlorosulfonylimide, comprising a step of adding a chlorinating reagent to the resultant of the above reaction.

18. In paragraph 17, The result of the above reaction contains at least one of an impurity H2O5NClS2 represented by the following chemical formula (IIa) and an impurity H3O6NS2 represented by the following chemical formula (IIIa), A method for producing bischlorosulfonylimide, characterized in that the step of adding the above chlorinating reagent is a step of removing impurities contained in the result of the above reaction. …chemical formula (IIa) …chemical formula (IIIa) 19. In paragraph 18, A method for producing bischlorosulfonylimide, characterized in that as a result of removing the above impurities, H2O5NClS2 remaining in the bischlorosulfonylimide is 10,000 ppm or less and H3O6NS2 is 10,000 ppm or less, respectively.

20. In paragraph 19, A method for producing bischlorosulfonylimide, characterized in that as a result of removing the above impurities, H2O5NClS2 remaining in the bischlorosulfonylimide is 7,100 ppm or less and H3O6NS2 is 6,700 ppm or less, respectively.

21. In paragraph 17, The above chlorinating reagent is, A method for producing bischlorosulfonylimide, characterized in that at least one selected from SOCl2, SO2Cl2, COCl2, C2O2Cl2, POCl3, PCl5, SbCl3, ClSO2NCO, SO2(NCO)2, SiCl4, ICl, ICl3, S2Cl2, SCl2, PCl3, COCl2, C6H5CCl3.

22. A step of reacting chlorosulfonyl isocyanate and chlorosulfonic acid to obtain bischlorosulfonylimide containing at least one of the impurities H2O5NClS2 and H3O6NS2; A step of removing the impurities by adding a chlorinating reagent to the bischlorosulfonylimide; and A method for producing a fluorosulfonylimide salt represented by chemical formula (Ia), comprising the step of adding butyl acetate to a fluorine compound, stirring the mixture, and then adding bischlorosulfonylimide from which the impurities have been removed. …chemical formula (Ia) (However, in the above chemical formula (Ia), M1 is one of NH4, Li, Na, K, Ca, Mg, Zn, Sb, Rb, and Cs, and A1 is a fluorine atom) 23. A step of reacting chlorosulfonyl isocyanate and chlorosulfonic acid to obtain bischlorosulfonylimide containing at least one of H2O5NClS2 represented by the following chemical formula (IIa) and H3O6NS2 represented by the following chemical formula (IIIa) as impurities; A step of removing the impurities by adding a chlorinating reagent to the above bischlorosulfonylimide; A step of obtaining bisfluorosulfonylimide ammonium salt from bischlorosulfonylimide from which the above impurities have been removed; and A method for producing a bisfluorosulfonylimide salt, comprising a step of obtaining a bisfluorosulfonylimide salt represented by the following chemical formula (Ib) from the bisfluorosulfonylimide ammonium obtained above. …chemical formula (IIa) …chemical formula (IIIa) …chemical formula (Ib) (However, in the above chemical formula (Ib), M2 is one of Li, Na, K, Ca, Mg, Zn, Sb, Rb, and Cs, A1 is a fluorine atom) 24. In paragraph 23, The bisfluorosulfonylimide salt obtained above contains an impurity [NS2O5F] represented by the following chemical formula (IIb): 2- and an impurity [NS2O6] represented by the following chemical formula (IIIb). 3- Containing at least one of the above [NS2O5F] 2- is less than 10,000 ppm and the above [NS2O6] 3- A method for producing a bisfluorosulfonylimide salt, characterized in that the content is 10,000 ppm or less. …chemical formula (IIb) …chemical formula (IIIb) 25. In paragraph 24, The above [NS2O5F] 2- is less than 7,100 ppm and the above [NS2O6] 3- A method for producing a bisfluorosulfonylimide salt, characterized in that the content is 6,700 ppm or less.

26. In paragraph 23, A method for producing a bisfluorosulfonylimide salt, characterized in that the bisfluorosulfonylimide salt has a pH of 6 or more and 9 or less in an aqueous solution state.

27. In paragraph 23, The above chlorinating reagent is, A method for producing a bisfluorosulfonylimide salt, characterized in that at least one selected from SOCl2, SO2Cl2, COCl2, C2O2Cl2, POCl3, PCl5, SbCl3, ClSO2NCO, SO2(NCO)2, SiCl4, ICl, ICl3, S2Cl2, SCl2, PCl3, COCl2, C6H5CCl3.

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