Compositions containing alkali metal salts of bis(fluorosulfonyl)imides

Abstract

The present invention relates to compositions containing alkali metal salts of bis(fluorosulfonyl)imides and to the use of such compositions in electrolytes for batteries.

Description

[Technical Field]

[0001] Cross-reference to related patent applications This application claims priority to European Patent Application No. 22209471.6, filed November 24, 2022, the entire contents of which are incorporated herein by reference for all purposes.

[0002] The present invention relates to compositions containing alkali metal salts of bis(fluorosulfonyl)imides and to the use of such compositions in electrolytes for batteries. [Background technology]

[0003] Bis(fluorosulfonyl)imides and their salts, particularly the lithium salt of bis(fluorosulfonyl)imide (LiFSI), are useful compounds in a variety of technical fields, such as in battery electrolytes.

[0004] Several methods for the preparation of LiFSI have been described in the art. Among the various techniques described, most use a fluorination reaction with a fluorinating agent in a solvent.

[0005] Much effort has also been devoted to improving the manufacturing methods of the intermediate compounds leading to LiFSI, especially with regard to purity, yield and cost reduction.

[0006] US Patent Application Publication No. 2014 / 0075746 (in the name of Arkema France) discloses a compound of the formula: (III) (SO3 - )-N - -(SO3 - )3C + (In the formula, C + represents a monovalent cation) The present invention discloses a process for preparing a bis(sulfonato)imide salt of This process is represented by the formula: (I) HO-SO2-NH2 of sulfamic acid with the formula: (II) HO-SO2-X (wherein X represents a halon atom) and cation C + This includes reaction with a base, the salt being formed by According to an embodiment of such a process, the reaction between compounds of formula (I) and (II) is carried out in a manner similar to that of the formula: (IV) HO-SO2-NH-SO2-OH which is then reacted with a cation C to provide a compound of formula (III) above. + The salt formed by reacting the compound with a second base is The compound of formula (III) thus obtained is further purified in water or other polar solvents such as alcohols.

[0007] U.S. Patent Application Publication No. 2017 / 0204124 (in the name of Central Glass Co., Ltd.) discloses ionic complexes that are said to contribute to the high temperature durability of non-aqueous electrolyte batteries. This patent document discloses, inter alia, an ionic complex of the formula: [ka] (In the formula, X 2 and X 3 are independently a fluorine atom or a group selected from alkyl, alkenyl, aryl, etc., and M 2 and M 3 is a proton, a metal cation, or an onium cation The compound is disclosed.

[0008] US Patent Application Publication No. 2020 / 0328474 (in the name of Central Glass Co., Ltd.) describes, inter alia, a compound of the formula: [ka] (In the formula, Z 2 , Z 3 and Z 5 Each of B can be a fluorine atom; + , C+ and D + are protons, metal ions, or onium ions, respectively. Further disclosed is an ionic complex containing the compound of formula:

[0009] The importance of purity of electrolyte compositions containing bis(fluorosulfonyl)imides is known in the art.

[0010] For example, European Patent No. 3316381 (Nippon Shokubai) discloses a liquid conductive material characterized by reduced turbidity and a method for producing and purifying such a conductive material. More specifically, the method is characterized by filtering a solution containing a fluorosulfonylimide salt using a filter containing at least one material selected from cellulose, polyester resin, silicon dioxide material, and activated carbon.

[0011] WO 2007 / 025361 (Hydro-Quebec) discloses a process for purifying an ionic electrolyte containing at least one alkali metal salt, the process comprising at least one step in which particles of at least one calcium salt are brought into contact. This process makes it possible to obtain an electrolyte characterized by a particularly low water content. Example 2 discloses a solution of LiFSI in ethylene carbonate and gamma-butyrolactone with a water content of 1000 ppm and a yellowish color, but after purification, the water content is reduced to 1 ppm and the solution color is light.

[0012] JP 2013-084562 A (Patent No. 6093516 A) (Nippon Shokubai Co., Ltd.) discloses an electrolyte containing an ionic compound and less than 25 ppm (by mass) of free acid. The electrolyte is produced by mixing the ionic compound with a hydrocarbon solvent and / or a carbonate solvent, followed by a step of distilling off some or all of the solvent, and / or a step of contacting the solution with a molecular sieve. In the examples, starting with a composition in which lithium bis(fluorosulfonyl)imide is dissolved in ethylene carbonate / ethyl methyl carbonate, a molecular sieve step is then performed, and the solution is then stored in an environment at a temperature of 25°C for two months.

[0013] International Publication No. 2020 / 242015 (SK Chemicals Co., Ltd.) discloses an electrolyte solution for secondary batteries that contains a combination of a small amount of stabilizer and a specific sulfate-based additive and / or sulfonate additive, and that retains its initial color or transparency (immediately after preparation of the electrolyte solution) for a long period of time in a temperature range from low to high.

[0014] Chinese Patent No. 112825371 (Zhuhai Cosmx Battery Co., Ltd.) discloses that the cycle performance and high-temperature storage performance of high-voltage lithium-ion batteries can be improved by adding 1,3,6-hexanetrinitrile to the electrolyte, and that the color of the electrolyte containing this substance can be controlled by controlling the color of 1,3,6-hexanetrinitrile, so that the color requirements for the production and storage of the electrolyte for lithium-ion batteries can be met.

[0015] Chinese Patent No. 113603069 (Jiangsu Huasheng Lithium Battery Material Co. Ltd.) discloses a method for removing trace impurities from lithium bis(trifluorosulfonate)imide, the method comprising the steps of: (1) adding a good solvent to a mixture of lithium bis(trifluorosulfonate)imide salt and an inert solvent to obtain a first filtrate after filtration; (2) adding a degermination agent to the filtrate to form a mixed solution, and filtering to obtain a second filtrate; and (3) distilling the second filtrate under reduced pressure to obtain a lithium bis(trifluorosulfonate)imide salt product. The index of the finished product of bis(fluorosulfone)imide lithium salt complies with one or more combinations of the following: ion chromatography content of 99.5 percent or more, sulfate impurity anion of 100 ppm or less, fluoride impurity anion of 200 ppm or less, sulfamate anion content of 10 ppm or less, fluorosulfonic acid impurity anion of 10 ppm or less, acidic impurities of 100 ppm or less, turbidity of 10 percent dimethyl carbonate solution of 20 mg / L or less, and color of 20 Hazen or less. Summary of the Invention

[0016] Applicant has recognized that, despite all of the attempts in the art, there remains a need for compositions comprising alkali metal salts of bis(fluorosulfonyl)imides that exhibit improved electrical properties when used in battery applications, which compositions are also easy to prepare on an industrial scale.

[0017] In particular, the applicant was faced with the problem of providing a composition that has a lower content of impurities compared to compositions known in the art. Indeed, contrary to the methods proposed in the art, the applicant was faced with the problem of providing a composition that can be prepared by the least expensive method when carried out on an industrial scale, in particular by limiting or avoiding the use of unusual compounds in the manufacturing process, reducing the need for additional purification steps.

[0018] The present applicant has unexpectedly discovered compositions comprising alkali metal salts of bis(fluorosulfonyl)imides, wherein such compositions are characterized by the presence of a specific compound in a predetermined amount. To the best of the applicant's knowledge, such compounds have not been disclosed in the art as ingredients in bis(fluorosulfonyl)imide compositions. Without being bound by any theory, the applicant is of the opinion that the presence of such compounds affects the electrical properties of the compositions of the present invention when compared to compositions already known in the art.

[0019] The compositions according to the present invention can be advantageously used as electrolytes in battery applications.

[0020] Disclosure of the Invention In this application: - All numerical ranges are to be understood as inclusive of their limits unless otherwise stated; - any description, even if made in relation to a particular embodiment, is applicable to and interchangeable with other embodiments of the invention; - When an element or component is said to be included in and / or selected from a list of enumerated elements or components, in related embodiments expressly contemplated herein, the element or component can also be any one of the individually enumerated elements or components, or can also be selected from a group consisting of any two or more of the explicitly enumerated elements or components; it should be understood that any element or component enumerated in a list of elements or components can be omitted from such list.

[0021] In a first aspect, the present invention provides a method for producing a medicament for the treatment of a pulmonary arthritis, comprising: - at least one alkali metal salt of bis(fluorosulfonyl)imide [FSI-salt]; at least one compound of formula (I) as shown below or an alkali metal salt thereof in an amount of 100 ppm or less, as measured by ion chromatography [ka] The present invention relates to a composition [composition (COMP)] comprising:

[0022] Preferably, composition (COMP) comprises said compound of formula (I) or an alkali metal salt thereof in an amount of less than 100 ppm, more preferably less than 75 ppm, even more preferably less than 50 ppm, and even more preferably less than 25 or less than 15 ppm.

[0023] Preferably, composition (COMP) comprises said compound of formula (I) or an alkali metal salt thereof in an amount of at least 0.1 ppm, more preferably at least 0.5 ppm, and even more preferably at least 1.0 ppm.

[0024] Optionally, the composition (COMP) may include further compounds and / or ingredients.

[0025] For example, the composition (COMP) is FSO3 - in an amount of up to 100 ppm as measured by ion chromatography.

[0026] Preferably, the composition (COMP) is FSO3 - The at least one alkali metal salt is contained in an amount of 0.1 ppm to 100 ppm, preferably 0.5 ppm to 50 ppm, more preferably 0.5 ppm to 20 ppm, and even more preferably 0.5 ppm to 5 ppm.

[0027] Alternatively or simultaneously, the composition (COMP) may have the formula (II): [ka] or an alkali metal salt thereof.

[0028] Preferably, said compound of formula (II) is in an amount of 100 ppm or less as measured by ion chromatography.

[0029] Preferably, composition (COMP) contains said compound (II) in an amount from 0.5 ppm, more preferably from 0.5 ppm to 100 ppm, even more preferably from 0.5 ppm to 50 ppm, even more preferably from 0.5 ppm to 20 ppm, and even more preferably from 0.5 ppm to 5 ppm. As further explained in the experimental section, the given amount of compound (II) is determined by ion chromatography and is based on the SO4 2- It is calculated based on the response factor.

[0030] For clarity, it should be understood that compounds (I) and (II) exist as depicted above or in their deprotonated forms.

[0031] For example, compound (I) exists as follows: [ka]

[0032] Similarly, compound (II) exists as follows: [ka]

[0033] Preferably, said alkali metal in the alkali metal salt of the compound of formula (I) and in the alkali metal salt of the compound of formula (II) in the FSI-salt, respectively, is selected from lithium, sodium and potassium.

[0034] Preferably, said composition (COMP) is a liquid composition.

[0035] According to this embodiment, the composition (COMP) further comprises at least one solvent [solvent (S1)].

[0036] Preferably, the at least one solvent (S1) is selected from the group comprising, more preferably consisting of, ethylene carbonate, propylene carbonate, butylene carbonate, γ-butyrolactone, γ-valerolactone, dimethoxymethane, 1,2-dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxane, 4-methyl-1,3-dioxolane, methyl formate, methyl acetate, methyl propionate, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, sulfolane, 3-methylsulfolane, dimethyl sulfoxide, N,N-dimethylformamide, N-methyloxazolidinone, acetonitrile, valeronitrile, benzonitrile, ethyl acetate, isopropyl acetate, n-butyl acetate, nitromethane, and nitrobenzene.

[0037] Even more preferably, said solvent (S1) is selected from ethylene carbonate, propylene carbonate, butylene carbonate, tetrahydrofuran, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, ethyl acetate, isopropyl acetate and n-butyl acetate, and even more preferred solvents include dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, ethyl acetate, isopropyl acetate and n-butyl acetate. Advantageously, said solvent (S1) is selected from ethyl methyl carbonate and n-butyl acetate.

[0038] More preferably, the composition (COMP) comprises 1 to 70 wt. %, even more preferably 5 to 50 wt. %, and even more preferably 15 to 40 wt. % of the at least one alkali metal salt of bis(fluorosulfonyl)imide, based on the total weight of the liquid composition.

[0039] Advantageously, the composition according to the invention (COMP) is further characterized by a low water content.

[0040] Preferably, the composition (COMP) has a water content of 15 ppm or less as measured by Karl Fischer titration.

[0041] Advantageously, the composition (COMP) according to the invention is further characterized by a low content of alcohol.

[0042] Preferably, the composition (COMP) has a total alcohol content of 20 ppm or less as measured by headspace gas chromatography (HS-GC-FID).

[0043] Preferably and advantageously, all raw materials used in the process according to the invention, including the reactants, may preferably exhibit very high purity.

[0044] Preferably, the content of metal components such as Na, K, Ca, Mg, Fe, Cu, Cr, Ni, and Zn is less than 10 ppm, more preferably less than 5 ppm, or less than 2 ppm.

[0045] The process for producing the composition (C) according to the present invention is not limited.

[0046] For example, according to one embodiment, the composition (COMP) is prepared by the following steps: (a) reacting bis(chlorosulfonyl)imide (HCSI) or a salt thereof with ammonium fluoride in a solvent to provide ammonium bis(fluorosulfonyl)imide (NH4-FSI) in the form of a suspension; (b) filtering the suspension obtained in step (a); (c) adding an anti-solvent to precipitate NH4-FSI in solid form; (d) reacting the NH4-FSI obtained in step (c) with at least one chlorinating agent comprising at least one alkali metal salt in a solvent to obtain a composition (COMP); It can be produced by a method comprising:

[0047] Steps (a) through (d) can be carried out in a batch, semi-batch or continuous manner.

[0048] Preferably, the HCSI is in solid form or in its molten state. More preferably, before step (a), if the HCSI is provided in its molten state, a step of preheating the HCSI to at least 40°C is carried out. Advantageously, said preheating step is carried out at a temperature above 40°C. More preferably, said preheating step is carried out at a temperature below 150°C.

[0049] As used above and within the present invention, the expression "ammonium fluoride" includes NH4F and the HF adduct of ammonium fluoride, e.g., NH4F(HF) n (wherein n is 1 to 10, preferably 1 to 4), more preferably NH4F.HF or NH4F(HF)2. The fluorinating agent may be commercially available or may be prepared by known methods.

[0050] Preferably, the ammonium fluoride is in solid form.

[0051] According to a preferred embodiment, the ammonium fluoride is anhydrous, and more preferably has a water content of 500 ppm or less.

[0052] The amount of ammonium fluoride used is preferably 2 to 5 equivalents per 1 mol of bis(chlorosulfonyl)imide or a salt thereof.

[0053] Preferably, the solvent in step (a) is selected from aprotic organic solvents. More preferably, the solvent is cyclic and acyclic carbonates, such as ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, cyclic and acyclic esters, such as gamma-butyrolactone, gamma-valerolactone, methyl formate, methyl acetate, methyl propionate, ethyl acetate, ethyl propionate, isopropyl acetate, propyl propionate, butyl acetate, cyclic and acyclic ethers, such as diethyl ether, diisopropyl ether, methyl tert-butyl ether, dimethoxymethane, 1,2-dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxane, 4-methyl-1,3-dioxane, 1,4-dioxane, amide compounds, such as N,N-dimethylformamide, N-methyloxazolidinone, sulfoxide and sulfone compounds, such as sulfolane, 3-methylsulfolane, dimethyl sulfoxide, cyano-, nitro-, chloro- or alkyl-substituted alkanes or aromatic hydrocarbons, such as acetonitrile, valeronitrile, adiponitrile, benzonitrile, nitromethane, nitrobenzene is selected from the group consisting of:

[0054] According to a preferred embodiment, the organic solvent for step (a) is selected from the group consisting of ethyl acetate, isopropyl acetate, butyl acetate, ethylene carbonate, dimethyl carbonate, ethyl methyl carbonate, propylene carbonate, valeronitrile and acetonitrile.

[0055] According to a preferred embodiment, the organic solvent is anhydrous.

[0056] Step (a) is preferably carried out at a temperature of 0°C to 200°C, preferably 30°C to 150°C, more preferably 50°C to 100°C.

[0057] Preferably, step (a) is carried out at atmospheric pressure, however, the reaction can be carried out below or above atmospheric pressure.

[0058] The order in which the reactants are added is not limited. According to a preferred embodiment, ammonium fluoride is first added to the organic solvent. Then, bis(chlorosulfonyl)imide or a salt thereof can be added to the reaction medium.

[0059] The method for producing the starting HCSI or a salt thereof is not limited.

[0060] For example, HCSI can be prepared by reacting chlorosulfonyl isocyanate with chlorosulfonic acid.

[0061] Preferably, the HCSI is prepared under heating, more preferably at a temperature in the range of 80°C to 180°C.

[0062] The HCSI thus obtained can be used directly in the process according to the invention, or it can be purified before being used in the process according to the invention, for example by distillation.

[0063] Preferably, the anti-solvent used in step (c) is selected from the group comprising, more preferably consisting of, dichloromethane, 1,2-dichloroethane, chloroform, carbon tetrachloride, 1,1,2,2-tetrachloroethane, chlorobenzene, dichlorobenzene, trichlorobenzene, diethyl ether, diisopropyl ether, methyl t-butyl ether, pentane, hexane, heptane, with dichloromethane being particularly preferred.

[0064] Preferably, the at least one alkali metal salt in the chlorinating agent used in step (d) is selected from lithium, sodium and potassium.

[0065] When the chlorinating agent contains lithium as an alkali metal salt, the agent is preferably lithium chloride (LiCl), lithium fluoride (LiF), lithium carbonate (LiCO), lithium sulfate (LiSO), lithium carboxylate (Li n (RCO2) n ), Li2SiO3, Li2B4O7 and mixtures thereof.

[0066] Preferably, the solvent in step (d) is selected from aprotic organic solvents, more preferably from the group comprising the solvents detailed above for step (a).

[0067] According to a preferred embodiment, the organic solvent for step (d) is selected from the group consisting of ethyl acetate, isopropyl acetate, butyl acetate, ethylene carbonate, dimethyl carbonate, ethyl methyl carbonate, propylene carbonate, valeronitrile and acetonitrile.

[0068] Step (d) is preferably carried out at a temperature of -50°C to 100°C, preferably -25°C to 50°C, more preferably -5°C to 10°C.

[0069] Preferably, step (d) is carried out at atmospheric pressure, however, the reaction can be carried out below or above atmospheric pressure.

[0070] In a further object, the present invention relates to the use of said composition (C) as a non-aqueous electrolyte solution in a battery.

[0071] If the disclosure of any patents, patent applications, and publications incorporated herein by reference contradicts the statements of this application to the extent that a term may be unclear, the statements of this application shall control.

[0072] The present invention will now be described in more detail with reference to the following examples, the purpose of which is illustrative only and is not intended to limit the scope of the disclosure. [Example]

[0073] method Ion Chromatography (IC). Anionic impurities were determined by IC using a Dionex ICS-3000 system with conductivity detection equipped with the following components: - Column: AS20 4*250mm Analytical & AG20 4*50mm Guard - Suppressor: ASRS 300-4mm, external water addition type.

[0074] F in LiFSI solution - , Cl - , FSO3 - (or LiFSO3) is obtained from a commercially available standard solution (F - , Cl - ) or quantitatively measured after calibration using commercial samples of KFSO3.

[0075] The amounts of compounds (I-NFSI) and (II-OFSI) were calculated by the SO4 2- Calculated based on response factors.

[0076] The alcohol content was measured by GC (Agilent 6890N network GC system) equipped with an FID detector and headspace injector using a split / splitless injection system.

[0077] LiFSI's 19 F-NMR purity was determined using the area % method on a Bruker advance NMR 300 MHz instrument.

[0078] [Table 1]

[0079] The water content of the final LiFSI solution was measured under an inert atmosphere using a KF Titrator, such as a Mettler C30S instrument.

[0080] Example 1 - Preparation of LiFSI Grade A according to the present invention Synthesis of HCSI. Glass-lined 2m with baffles, mechanical stirring shaft, glass-lined DN300 distillation column and heat exchanger, pressure and temperature sensors and glass-lined liquid and gas inlets and outlets, PFTE vent, PTFE gaskets and receiving glass-lined tank. 3Chlorosulfonyl isocyanate (983 kg) and chlorosulfonic acid (850 kg) were reacted in a vessel, the entire system connected to an alkaline scrubber, by gradually heating to 100-120°C over 22 h until gas evolution ceased, then to 140-145°C. The reaction mixture was distilled to isolate the pure HCSI fraction (1100 kg).

[0081] Synthesis of ammonium-FSI. PFA-lined 5m reactor equipped with PFA-lined baffles, PFA-coated shaft of mechanical stirring, PTFE-lined connectors, and heat exchanger. 3 Ethyl methyl carbonate (3200 kg) and anhydrous ammonium fluoride (840 kg) were introduced into a vessel, the entire system of which was connected to an alkaline scrubber. The suspension was homogenized, after which HCSI (1098 kg) obtained as disclosed above was gradually introduced, while maintaining the temperature of the mixture below 80°C. After complete addition, the suspension was heated at 80°C for 22 h and cooled to room temperature (RT). The resulting slurry was filtered, and the cake was washed with additional ethyl methyl carbonate (800 kg). The resulting filtrate (4639 kg) was transferred to a separate 5m evaporator equipped with a mechanical stirring shaft, baffles, liquid and gas inlets and outlets, and a distillation apparatus. 3 The filtrate was mixed with water (139 kg) and 25% aqueous ammonia (30 kg) and stirred at room temperature for 1 h. The wet ethyl methyl carbonate was then distilled off and the resulting concentrate (1482 kg) was filtered and transferred to a glass-lined 5 m jar equipped with a baffle, a mechanical stirring shaft and a heat exchanger. 3 The filtered concentrate was precipitated by the controlled addition of dichloromethane (2400 kg). The resulting slurry was poured into a stainless steel 5 m 3The mixture was filtered onto a filter. The cake was washed with additional dichloromethane (600 kg). Crude ammonium bis(fluorosulfonyl)imide was isolated as a wet solid and further dried to give a crude dry product (888 kg). The crude NHFSI was divided into three batches, and each batch was purified separately. A 5 m 2000 sieve was prepared using a 5000 sieve press equipped with baffles, a mechanical stirring shaft, a heat exchanger, pressure and temperature sensors, liquid and gas inlets and outlets, a PTFE vent, PTFE gaskets, and a receiving tank. 3 Each batch was dissolved at 20 wt. % in trifluoroethanol at 60-65°C in a steel vessel, the entire system connected to an organic vapor management system. After complete dissolution, 1,4-dioxane was added over 3 h. After complete 1,4-dioxane addition, the suspension was cooled to 25°C over 3 h and maintained at RT for 12 h. The resulting slurry was filtered, and the white solid thus obtained was washed with TFE / dioxane (75 / 25 w / w). This protocol was repeated until the impurity profile met the intermediate specifications.

[0082] Synthesis of LiFSI. A 5 m glass-lined chamber equipped with baffles, a mechanical stirring shaft, and a heat exchanger. 3 In a vessel, lithiation was carried out as follows: A 10 wt% solution (based on NHFSI) of NHCl.dioxane in ethyl methyl carbonate was prepared, filtered, and then subjected to a first lithiation step by adding 1.1 equivalents of LiOH.H2O to the solution at atmospheric pressure (Patm) and 0 °C. This mixture was heated at 0 °C for 22 h. atm The second step of ammonia removal was then carried out with NH4 + This was continued until the residual content was less than 10 ppm and the residual 1,4-dioxane content was less than 100 ppm. All three batches were filtered in turn, and the obtained filtrate was subjected to distillation.

[0083] Three batches were obtained, each containing 30 wt% LiFSI in EMC, that were characterized by NMR, GC headspace, ion chromatography, KF, ICP, turbidimetry, colorimetry, and pH. The results are reported as averages in Table 1.

[0084] Comparative Example 1 - Preparation of Comparative LiFSI Grade B The LiFSI solution used in Comparative Example 1 is prepared according to the method described in Examples 1 and 3 of the patent application published as WO 2021 / 074142 (in the name of Solvay SA).

[0085] Three batches, each containing 30 wt% LiFSI in EMC, were obtained and characterized by NMR, GC headspace, ion chromatography, KF, ICP, and pH. The results are reported as averages in Table 1.

[0086] [Table 2]

[0087] Each of the compositions containing EMC and LiFSI prepared as described above in Example 1 and Comparative Example 1 was used to prepare a formulation suitable for testing in a pouch cell.

[0088] Three batches of Formulation A according to the invention were prepared. Two comparative batches of Formulation B were prepared. Formulations A and B contained the ingredients shown below.

[0089] [Table 3]

[0090] A commercial solution of 5 wt% LiFSI in EMC (considered a benchmark in the art) was used as a further comparison.

[0091] The pouch cell was as follows: NCM622 / graphite (4.2V, 965.3mAh) made of UTP. The test temperature was 45°C. Charge: 1C / 4.2V (CC-CV). Discharge: 1C / 3.0C (CC).

[0092] The cells were tested for discharge capacity and thickness change, and the results are summarized in the table below.

[0093] [Table 4]

[0094] [Table 5]

[0095] As shown in Table 2, the formulations according to the present invention exhibited higher initial discharge capacities than the benchmark, and after 500 cycles, they maintained comparable retention capacities to the benchmark. Separately, as shown in Table 3, compared to the benchmark, the formulations according to the present invention had lower thickness change during storage tests at 60°C (which is due to reduced gas generation and decomposition within the pouch cell).

[0096] In contrast, the (comparative) formulation B had an initial discharge capacity below 900, which was lower than that of the formulation A according to the invention.

Claims

1. A composition [composition (COMP)] comprising: at least one alkali metal salt of a bis(fluorosulfonyl)imide [FSI-salt]; - compounds of formula (I) as represented in the following formula, in an amount of less than or equal to 100 ppm, as determined by ion chromatography: 【Chemistry 1】 or an alkali metal salt thereof A composition comprising [composition (COMP)].

2. 2. The composition (COMP) of claim 1, wherein the compound of formula (I) or the alkali metal salt thereof is present in an amount of less than 100 ppm, preferably less than 75 ppm, more preferably less than 50 ppm, even more preferably less than 25 ppm and / or in an amount of at least 0.1 ppm, more preferably at least 0.5 ppm, even more preferably at least 1.0 ppm.

3. The composition (COMP) comprises at least one FSO ３ － 3. A composition (COMP) according to claim 1 or 2, comprising an alkali metal salt of:

4. The FSO ３ － 4. The composition (COMP) of claim 3, wherein the alkali metal salt of is in an amount of from 0.1 ppm to 100 ppm or less as measured by ion chromatography.

5. The composition (COMP) is a compound of formula (II) as represented in the following formula: 【Chemistry 2】 The composition (COMP) according to any one of claims 1 to 4, comprising at least one compound of the formula (I) or an alkali metal salt thereof.

6. 6. The composition (COMP) of claim 5, wherein said compound of formula (II) or said alkali metal salt thereof is in an amount of from 0.5 ppm and / or not more than 100 ppm as measured by ion chromatography.

7. 7. A composition (COMP) according to any one of claims 1 to 6, wherein the alkali metal in the alkali metal salt of the compound of formula (I) and in the alkali metal salt of the compound of formula (II) in each of the FSI-salts is selected from lithium, sodium or potassium.

8. The composition (COMP) according to any one of claims 1 to 7, wherein the composition (COM) is a liquid composition.

9. 9. The composition (COMP) according to claim 8, wherein said composition (COMP) further comprises at least one solvent [solvent (S1)].

10. 10. The composition (COMP) of claim 9, wherein the at least one solvent (S1) is selected from the group comprising, more preferably consisting of, ethylene carbonate, propylene carbonate, butylene carbonate, γ-butyrolactone, γ-valerolactone, dimethoxymethane, 1,2-dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxane, 4-methyl-1,3-dioxolane, methyl formate, methyl acetate, methyl propionate, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, sulfolane, 3-methylsulfolane, dimethyl sulfoxide, N,N-dimethylformamide, N-methyloxazolidinone, acetonitrile, valeronitrile, benzonitrile, ethyl acetate, isopropyl acetate, n-butyl acetate, nitromethane and nitrobenzene.

11. 11. Composition (COMP) according to any one of claims 1 to 10, wherein said composition (COMP) comprises 1 to 70 wt. %, even more preferably 5 to 50 wt. %, even more preferably 15 to 40 wt. % of said FSI-salt, based on the total weight of the liquid composition.

12. 12. Composition (COMP) according to any one of claims 1 to 11, wherein said composition (COMP) has a water content of not more than 15 ppm as measured by Karl Fischer titration.

13. 13. The composition (COMP) of any one of claims 1 to 12, wherein the composition (COMP) has a total alcohol content of 20 ppm or less as measured by headspace gas chromatography (HS-GC-FID).

14. Use of a composition (COMP) according to any one of claims 1 to 13 as a non-aqueous electrolyte solution in a battery.

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