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 the use of such compositions in battery electrolytes.

Description

[Technical Field]

[0001] Cross-reference to related patent applications This application claims priority to European application No. 22209474.0 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 the use of such compositions in battery electrolytes. [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, including battery electrolytes.

[0004] Several methods for producing LiFSI have been described in the art. Of the various techniques described, most use a fluorination reaction using a fluorinating agent in a solvent.

[0005] Much effort has also been made in the art to improve the manufacturing processes of intermediate compounds to obtain LiFSI, especially in terms of 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) 1. A process for preparing a bis(sulfonato)imide salt of the formula: (I) HO-SO2-NH2 amidosulfuric acid of the formula: (II) HO-SO2-X (wherein X represents a halon atom) with a halosulfonic acid of and cation C + and reacting with a base that is a salt formed using: According to one embodiment of such a method, the reaction between the compound of formula (I) and the compound of formula (II) is carried out in the presence of a first base to form a compound of formula: (IV) HO-SO2-NH-SO2-OH which then gives the bis(sulfonyl)imide of cation C + to give the compound of formula (III) above. 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 specifically describes ionic complexes of the following 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, the following formula: [ka] (In the formula, Z 2 , Z 3 , and Z 5 may each be a fluorine atom, and B + , C+ , and D + are protons, metal ions, or onium ions, respectively. Further disclosed is an ionic complex comprising 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 Specification No. 3316381 (Nippon Shokubai Co., Ltd.) 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 (fluorosulfonyl)imide salt through 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 method for purifying an ionic electrolyte containing at least one alkali metal salt, which method comprises at least one step of contacting particles of at least one calcium salt. This method allows for the production of an electrolyte characterized by a particularly low water content. Example 2 discloses a solution of LiFSI in ethylene carbonate and γ-butyrolactone with a water content of 1000 ppm and a yellowish color; after purification, the water content is reduced to 1 ppm and the solution is light in color.

[0012] JP 2013-084562 A (Nippon Shokubai Co., Ltd.) discloses an electrolyte solution containing an ionic compound and less than 25 ppm (by mass) of free acid. The electrolyte solution is produced by mixing the ionic compound with a hydrocarbon solvent and / or a carbonate solvent, followed by distilling off part or all of the solvent and / or contacting the solution with a molecular sieve. The examples start with a composition in which lithium bis(fluorosulfonyl)imide is placed in ethylene carbonate / ethyl methyl carbonate, followed by a molecular sieve step, and then the solution is 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 the solution retains its initial color or transparency (immediately after preparation of the electrolyte solution) for a long period of time over 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 Materials Co. Ltd.) discloses a method for removing trace impurities from lithium bis(trifluorosulfonate)imide, which includes: (1) adding a good solvent to a mixture of lithium bis(trifluorosulfonate)imide salt and an inert solvent, and obtaining a first filtrate after filtration; (2) adding a degermination agent to the filtrate to form a mixed solution, and obtaining a second filtrate after filtration; and (3) distilling the second filtrate under reduced pressure to obtain a lithium bis(trifluorosulfonate)imide salt product. The indicators for the final product of bis(fluorosulfone)imide lithium salt shall satisfy one or more of the following combinations: content determined by ion chromatography shall be 99.5 percent or more, anions that are sulfate impurities shall be 100 ppm or less, anions that are fluoride impurities shall be 200 ppm or less, anions that contain sulfamic acid shall be 10 ppm or less, anions that are fluorosulfonic acid impurities shall be 10 ppm or less, acidic impurities shall be 100 ppm or less, the turbidity of a 10% dimethyl carbonate solution shall be 20 mg / L or less, and the color shall be 20 Hazens or less. Summary of the Invention

[0016] Applicants recognize that, despite all 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, and that are also easy to prepare on an industrial scale.

[0017] In particular, the applicant was faced with the problem of providing a composition with a lower content of impurities compared to compositions known in the art. Indeed, in contrast to the methods proposed in the art, the applicant was faced with the problem of providing a composition that can be prepared by the most inexpensive method when carried out on an industrial scale, by limiting or avoiding the use of particularly special compounds in the preparation method. This preparation method reduces the need for additional purification steps.

[0018] Applicants have surprisingly discovered compositions containing alkali metal salts of bis(fluorosulfonyl)imides, characterized by specific amounts of specific compounds. Furthermore, to Applicants' knowledge, such formulations are characterized by the presence of specific compounds that have never before been disclosed in the art as components of bis(fluorosulfonyl)imide compositions. Advantageously, the formulations of the present invention are characterized by superior electrical properties when compared to currently commercially available compositions.

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

[0020] In this application: - Unless otherwise specified, all numerical ranges are to be understood as inclusive; - any description, even if made in relation to a particular embodiment, is applicable to and interchangeable with other embodiments of the invention; - Where an element or component is referred to as being included in and / or selected from a list of enumerated elements or components, it is to be understood that in the relevant embodiments expressly contemplated herein, the element or component may be any one of the individually enumerated elements or components, or may also be selected from a group consisting of any two or more of the explicitly enumerated elements or components, and that any element or component enumerated in a list of elements or components may 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 FSO3 in an amount of up to 100 ppm as determined by ion chromatography - alkali metal salts of; - The following in amounts up to 100 ppm as determined by ion chromatography: [ka] at least one compound of formula (I) represented by: or a salt thereof; - The following in amounts up to 100 ppm as determined by ion chromatography: [ka] or a salt thereof; The present invention relates to a composition [composition (COMP)] comprising:

[0022] Preferably, the composition (COMP) contains the at least one FSO3 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. - Including alkali metal salts of

[0023] Preferably, the composition (COMP) contains the compound of formula (I) or its alkali metal salt 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 less than 0.5 ppm to 5 ppm.

[0024] Preferably, the composition (COMP) contains the compound (II) in an amount of 0.5 ppm to 100 ppm, more 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. As further explained in the experimental section, the amounts disclosed herein above for compound (II) are measured by ion chromatography and are based on the SO4 2- It is calculated based on the sensitivity coefficient.

[0025] For clarity, it should be understood that compounds (I) and (II) exist in the as-shown form or in their deprotonated form.

[0026] For example, compound (I) exists as follows: [ka]

[0027] Similarly, compound (II) exists as follows: [ka]

[0028] Preferably, FSO3 - wherein the alkali metal in each FSI-salt is selected from lithium, sodium, and potassium.

[0029] Preferably, each of said salts of the compound of formula (I) and the compound of formula (II) is a salt with an alkali metal, said alkali metal preferably being selected from lithium, sodium and potassium.

[0030] Preferably, said composition (COMP) is a liquid composition.

[0031] According to this embodiment, the composition (COMP) further comprises at least one solvent [solvent (S1)].

[0032] 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.

[0033] 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, more preferred solvents being 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.

[0034] More preferably, the composition (COMP) comprises 1 to 70 wt. %, more preferably 5 to 50 wt. %, and even more preferably 15 to 40 wt. % of the alkali metal salt of the at least one bis(fluorosulfonyl)imide, based on the total weight of the liquid composition.

[0035] Advantageously, the composition (COMP) according to the invention is further characterized by a low water content.

[0036] Preferably, the composition (COMP) has a water content of 15 ppm or less as measured by Karl Fischer titration.

[0037] Advantageously, the composition (COMP) according to the invention is further characterized by a low alcohol content.

[0038] Preferably, the composition (COMP) has a total alcohol content of 20 ppm or less as measured by headspace gas chromatography (HS-GC-FID).

[0039] Advantageously, all raw materials, such as all reactants, used to prepare composition (COMP) preferably exhibit very high purity.

[0040] Preferably, the content of metal components such as Na, K, Ca, Mg, Fe, Cu, Cr, Ni, and Zn in such raw materials and reactants is less than 10 ppm, more preferably less than 5 ppm, or less than 2 ppm.

[0041] The method for producing the composition (COMP) according to the present invention is not limited.

[0042] For example, according to one embodiment, the composition (COMP) may be produced by a method comprising the steps of: (a) reacting bis(chlorosulfonyl)imide (HCSI) or a salt thereof with ammonium fluoride in a solvent to obtain 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 salt-forming agent comprising at least one alkali metal salt in a solvent to obtain a composition (COMP).

[0043] Steps (a) through (d) can be carried out in a batch, semi-batch, or continuous manner.

[0044] Preferably, the HCSI is in solid form or in its molten state. More preferably, when the HCSI is obtained in the molten state, step (a) is preceded by a step of preheating the HCSI to a temperature of at least 40°C. 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.

[0045] The term "ammonium fluoride" as used above and within the present invention 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 is commercially available or can be prepared by known methods.

[0046] Preferably, the ammonium fluoride is in solid form.

[0047] According to a preferred embodiment, the ammonium fluoride is anhydrous. More preferably, the water content is 500 ppm or less.

[0048] The amount of ammonium fluoride used is preferably 2 to 5 equivalents per mole of bis(chlorosulfonyl)imide or a salt thereof.

[0049] 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 The compound is selected from the group comprising:

[0050] According to a preferred embodiment, the organic solvent in 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.

[0051] According to a preferred embodiment, the organic solvent is anhydrous.

[0052] Step (a) is carried out at a temperature of 0°C to 200°C, preferably 30°C to 150°C, and more preferably 50°C to 100°C.

[0053] Preferably, step (a) is carried out at atmospheric pressure, however, the reaction can be carried out below or above atmospheric pressure.

[0054] The order of adding the reactants 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.

[0055] There is no limitation on the method for producing the starting material, HCSI or a salt thereof.

[0056] For example, HCSI can be prepared by reacting chlorosulfonyl isocyanate with chlorosulfonic acid.

[0057] Preferably, the HCSI is prepared under heating, more preferably at a temperature in the range of 80°C to 180°C.

[0058] 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.

[0059] 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.

[0060] Preferably, the at least one alkali metal salt in the salt former used in step (d) is selected from lithium, sodium, and potassium.

[0061] When the salt former contains lithium as an alkali metal salt, the salt former is preferably lithium chloride (LiCl), lithium fluoride (LiF), lithium carbonate (Li2CO3), lithium sulfate (Li2SO4), lithium carboxylate (Li n (RCO2) n ), Li2SiO3, Li2B4O7, and mixtures thereof.

[0062] 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).

[0063] According to a preferred embodiment, the organic solvent in 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.

[0064] 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.

[0065] Preferably, step (d) is carried out at atmospheric pressure, however, the reaction can be carried out below or above atmospheric pressure.

[0066] In a further object, the present invention relates to the use of said composition (COMP) as a non-aqueous electrolyte in a battery.

[0067] To the extent that the disclosure of any patents, patent applications, and publications incorporated herein by reference conflicts with the statements of this application to the extent that the term may be unclear, the present statements shall control.

[0068] 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 present disclosure. [Example]

[0069] 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.

[0070] F in LiFSI solution - , Cl- , FSO3 - (or LiFSO3) is obtained from a commercially available standard solution (F - , Cl - ) or KFSO3 were quantitatively measured after calibration using commercial samples.

[0071] The amount of compounds (I) and (II) is 2- Calculations were based on sensitivity coefficients.

[0072] The alcohol content was determined by GC (Agilent 6890N network GC system) with a split / splitless injection system equipped with an FID detector and a headspace injector.

[0073] LiFSI's 19 F-NMR purity was determined using the area % method on a Bruker advance NMR 300 MHz instrument.

[0074] [Table 1]

[0075] The water content of the final LiFSI solution was determined in an inert atmosphere by a KF titration apparatus such as a Mettler C30S apparatus.

[0076] Example 1: Preparation of LiFSI Grade A according to the present invention Synthesis of HCSI. A glass-lined 2m distillation column was equipped with baffles, a mechanical stirring shaft, a glass-lined DN300 distillation column, a heat exchanger, pressure and temperature sensors, glass-lined liquid and gas inlets and outlets, a PTFE vent, a PTFE gasket, and a glass-lined receiver tank, with the entire system connected to an alkaline scrubber. 3In a vessel, chlorosulfonyl isocyanate (983 kg) and chlorosulfonic acid (850 kg) were reacted by gradually heating to 100-120°C and then to 140-145°C for 22 hours until gas evolution ceased. The reaction mixture was distilled to isolate the pure HCSI fraction (1100 kg).

[0077] Synthesis of ammonium-FSI. A PFA-lined 5m sintered reactor was used, equipped with PFA-lined baffles, a PFA-coated mechanical stirring shaft, a PTFE-lined connector, and a heat exchanger, with the entire system connected to an alkaline scrubber. 3 A vessel was charged with ethyl methyl carbonate (3200 kg) and anhydrous ammonium fluoride (840 kg). After homogenizing the suspension, HCSI (1098 kg) obtained as disclosed above was gradually introduced while maintaining the temperature of the mixture below 80°C. After the addition was complete, the suspension was heated at 80°C for 22 hours 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 another 5 m 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 hour. 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 evaporator 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 transferred to a stainless steel 5 m 3The mixture was filtered on a 500-kJ filter and 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 500-kJ / 2500 m2 reactor was equipped with baffles, a mechanical stirring shaft, a heat exchanger, pressure and temperature sensors, liquid and gas inlets and outlets, a PTFE vent, a PTFE gasket, and a receiver, and the entire system was connected to an organic vapor management system. 3 Each batch was dissolved in trifluoroethanol at 20 wt. % in a steel vessel at 60-65°C. After complete dissolution, 1,4-dioxane was added over 3 hours. After the addition of 1,4-dioxane was complete, the suspension was cooled to 25°C over 3 hours and then maintained at room temperature for 12 hours. 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 desired specifications for the intermediate.

[0078] Synthesis of LiFSI. Lithiation was carried out in a glass-lined 5m reactor equipped with a baffle, a mechanical stirring shaft, and a heat exchanger. 3 The first lithiation step was carried out in a vessel as follows: A solution of 10 wt% (based on NHFSI) NHCl.dioxane in ethyl methyl carbonate was prepared and filtered, after which 1.1 equivalents of LiOH.H2O were added to the solution at atmospheric pressure (Patm) and 0°C. This mixture was then heated at 0°C for 1 hour. atm The mixture was stirred at rt for 22 h. A second step of ammonia removal was then carried out by removing the remaining NH + This was done until the content was <10 ppm and the residual 1,4-dioxane content was <100 ppm, after which all three batches were filtered and the resulting filtrate was subjected to distillation.

[0079] Three batches, each containing 30 wt% LiFSI in EMC, were obtained and characterized by NMR, GC headspace, ion chromatography, KF, ICP, turbidity, colorimetry, and pH. The results are reported as averages in Table 1.

[0080] 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 patent application published under WO 2021 / 074142 (in the name of Solvay SA).

[0081] 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.

[0082] [Table 2]

[0083] 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.

[0084] Three batches of Formulation A according to the invention were prepared. Two batches of comparative Formulation B were prepared. Formulations A and B contained the following ingredients:

[0085] [Table 3]

[0086] A commercial solution of 5 wt% LiFSI in EMC (considered a benchmark in this field) was used as a further comparison.

[0087] The pouch cell was as follows: NCM622 / UTP graphite (4.2V, 965.3mAh). The test temperature was 45°C. Charge: 1C / 4.2V (CC-CV). Discharge: 1C / 3.0C (CC).

[0088] The cells were tested for discharge capacity and thickness change, and the results are summarized in the table below.

[0089] [Table 4]

[0090] [Table 5]

[0091] As shown in Table 3, the formulations according to the present invention exhibited higher initial discharge capacity than the benchmark and maintained comparable retention capacity to the benchmark after 500 cycles. In contrast, as shown in Table 4, the formulations according to the present invention showed less thickness change during storage testing at 60°C compared to the benchmark (this is due to gas evolution and decomposition within the pouch cell).

[0092] In contrast, formulation B (comparison) had an initial discharge capacity of less than 900, which was lower than that of 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]; at least one FSO in an amount of up to 100 ppm as determined by ion chromatography ３ － alkali metal salts of; - in an amount of up to 100 ppm, as determined by ion chromatography, of the following formula: 【Chemistry 1】 or a salt thereof; and - in an amount of up to 100 ppm, as determined by ion chromatography, of the following formula: 【Chemistry 2】 at least one compound of formula (II) represented by: or a salt thereof; A composition comprising [composition (COMP)].

2. said at least one FSO ３ － The composition (COMP) according to claim 1, wherein the alkali metal salt of is 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.

3. The composition (COMP) according to claim 1 or 2, wherein the compound of formula (I) or a salt thereof is present in an amount of from 0.1 ppm to 100 ppm, preferably from 0.5 ppm to 50 ppm, more preferably from 0.5 ppm to 20 ppm, and even more preferably from less than 0.5 ppm to 5 ppm, as measured by ion chromatography.

4. The compound (II) or a salt thereof is measured by ion chromatography and has a concentration of SO ４ ２－ The composition (COMP) according to any one of claims 1 to 3, which is present in an amount of from 0.5 ppm to 100 ppm, more preferably from 0.5 ppm to 50 ppm, more preferably from 0.5 ppm to 20 ppm, and even more preferably from 0.5 ppm to 5 ppm, calculated based on a sensitivity factor.

5. FSO in each of the FSI-salts ３ － The composition (COMP) according to any one of claims 1 to 4, wherein the salts of the compounds of formula (I) and of the compounds of formula (II) are salts with lithium, sodium, and potassium.

6. The composition (COMP) according to any one of claims 1 to 5, which is a liquid composition.

7. 7. The composition (COMP) according to claim 6, further comprising at least one solvent [solvent (S1)].

8. 8. Composition (COMP) according to claim 7, wherein the at least one solvent (S1) is selected from the group comprising, more preferably from the group 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.

9. 9. A composition (COMP) according to any one of claims 1 to 8, comprising 1 to 70 wt.-%, more preferably 5 to 50 wt.-%, even more preferably 15 to 40 wt.-% of said at least one FSI-salt, based on the total weight of the liquid composition.

10. 10. The composition (COMP) according to any one of claims 1 to 9, having a water content of not more than 15 ppm as measured by Karl Fischer titration.

11. A composition (COMP) according to any one of claims 1 to 10, having a total alcohol content of 20 ppm or less as measured by headspace gas chromatography (HS-GC-FID).

12. Use of a composition (COMP) according to any one of claims 1 to 11 as a non-aqueous electrolyte in a battery.

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