Electrolytes comprising sulfonamides and lithium salts, electrochemical cells and batteries comprising said electrolytes, methods of preparation and uses thereof

Abstract

The present invention relates to a liquid electrolyte comprising: i. At least one sulfonamide having the general formula CHF2-S (O) 2-NR1R2, wherein R1 and R2 are independently selected from the group consisting of a linear or branched C1-C12 alkyl group which may be substituted by one or more fluorine atoms, a linear or branched C2-C12 alkenyl group which may be substituted by one or more fluorine atoms, a C6-C12 aryl group which may be substituted by one or more fluorine atoms, and CH2CH2O-(CH2CH2O) n-R3 wherein R3 is a methyl or ethyl group, and n is an integer from 0 to 20; or R1 and R2 may bind to each other to form a nitrogen-containing aliphatic ring; and ii. At least one lithium salt; the electrolyte is further characterized in that the electrolyte does not comprise polymers other than sulfonamide-containing polymers, and when the combination of i) and ii) is in solid form, the electrolyte further comprises at least one solvent suitable for dissolving the combination. Some significant advantages of the new electrolytes are improved thermal stability and conductivity. The invention also relates to an electrochemical cell or battery comprising said electrolyte. The impedance and voltage profiles of electrochemical cells or cells comprising the electrolytes of the invention are advantageous compared to systems of the prior art. In addition, the invention discloses sulfonamides having the general formula CHF2-S (O) 2-NR1R2 useful in the preparation of liquid electrolytes. The invention also relates to a method for preparing sulfonamides, liquid electrolytes and electrochemical cells or batteries comprising the same.

Description

Technical Field

[0001] This invention relates to the field of electrolytes, particularly liquid electrolytes, for use in electrochemical single cells or batteries. This invention can find wide applications in energy storage and electronic devices. Background Technology

[0002] Lithium metal batteries (LMBs) arguably represent an attractive technology for energy storage applications due to their high energy density and ultra-low redox potential. Commercial batteries primarily use liquid electrolytes (LEs) as the ion transport medium because of their high ionic conductivity and excellent wettability with electrodes and separators. Solid electrolytes, on the other hand, such as those made of polymers, ceramics, or mixtures thereof, are characterized by lower conductivity than that of conventional liquid electrolytes.

[0003] Typical liquid electrolytes are organic carbonates and ethers, such as ethylene carbonate (EC), ethyl methyl carbonate (EMC), and 1,2-dimethoxyethane (DME). However, liquid electrolytes can be associated with low thermal stability and suboptimal electrode-electrolyte interface resistance. These issues represent major obstacles to the practical application of liquid electrolytes in liquid metallurgical (LMB) systems.

[0004] Several sulfonamides have been used as components of liquid electrolytes; however, other organic carbonates are usually required to achieve stable electrochemical cycling.

[0005] For example, document EP3050872A1 relates to including formula R 1 -SO2-NR2R3 fluorosulfonamides are used as part of the solvent system and the electrolyte solution of the electrolyte salt. However, this literature teaches that flammable carbonate solvents are very important for solving the corresponding technical problems (e.g., aluminum current collector corrosion) while maintaining high electrolyte conductivity.

[0006] US9065146B2 describes a non-aqueous electrolyte comprising a non-aqueous organic solvent and a lithium salt dissolved therein, wherein the non-aqueous organic solvent comprises at least one compound selected from acid anhydrides and carbonates having unsaturated bonds, and at least one compound selected from sulfonic acid compounds and fluorinated aromatic compounds having nine or fewer carbon atoms.

[0007] WO2022216593A1 discloses an electrolyte and electrochemical single cell comprising asymmetric sulfonamide, lithium salt and carbonate.

[0008] US8802301B2 relates to an ionic liquid composition as an electrolyte for lithium-ion batteries, comprising an alkylsulfonamide or arylsulfonamide and lithium fluoroalkylsulfonamide or lithium fluoroarylsulfonamide at a specific sulfonamide / lithium salt ratio, and the resulting mixture having a Tg below -50°C.

[0009] WO2022053881A1 discloses an electrolyte composition comprising one or more sulfonyl-based solvents for use in electrochemical devices such as secondary batteries. The electrolyte may contain one or more salts, such as one or more alkali metal salts, dissolved in the sulfonyl-based solvent system.

[0010] Despite progress in this field, no electrolyte system has yet been found that exhibits improved thermal stability, improved interfacial resistance, and / or high conductivity. Therefore, there is a need in the art to develop new electrolyte systems (particularly liquid electrolytes) that overcome the thermal stability problems of existing liquid electrolytes while simultaneously providing practical electrochemical performance for a wide range of applications. Summary of the Invention

[0011] This invention relates to liquid electrolytes comprising sulfonamides and lithium salts, characterized in that the liquid electrolyte does not contain polymers other than the sulfonamide-containing polymer, provided that when the combination of sulfonamide and lithium salt is in solid form, the electrolyte also contains at least one solvent suitable for dissolving the combination of sulfonamide and lithium salt. The inventors have discovered that such electrolyte compositions exhibit advantageous properties, such as high thermal stability and improved interfacial resistance, without compromising electrolyte conductivity.

[0012] Therefore, a first aspect of the present invention relates to a liquid electrolyte comprising:

[0013] i. At least one sulfonamide having the general formula I,

[0014] ;

[0015] R1 and R2 are independently selected from linear or branched C1-C atoms that can be substituted by one or more fluorine atoms. 12 Alkyl groups, linear or branched C2-C atoms that may be substituted with one or more fluorine atoms. 12 Alkenyl groups, C6-C atoms that can be substituted with one or more fluorine atoms 12 Aryl groups, and CH2CH2O-(CH2CH2O) n -R3, where R3 is methyl or ethyl, and n is an integer from 0 to 20; or R1 and R2 can combine with each other to form a nitrogen-containing aliphatic ring; and

[0016] i. At least one lithium salt;

[0017] The electrolyte is further characterized in that:

[0018] - The electrolyte does not contain polymers other than sulfonamide-containing polymers, and

[0019] - When the combination of i) and ii) is in solid form, the electrolyte further comprises at least one solvent suitable for dissolving the combination.

[0020] A second aspect of the invention relates to an electrochemical single cell or battery comprising the electrolyte of the invention as defined above.

[0021] A third aspect of the present invention relates to a method for preparing the electrolyte of the first aspect of the present invention, comprising the following steps:

[0022] (i) Provide at least one lithium salt;

[0023] (ii) Mix at least one sulfonamide of formula I with at least one lithium salt of step (i) to obtain a first mixture;

[0024] (iii) When the first mixture is in solid form, at least one solvent suitable for dissolving the first mixture is added to the first mixture, thereby obtaining a second mixture; and

[0025] (iv) Stir the mixture from step (ii) or (iii).

[0026] Another aspect of the invention relates to the use of the electrochemical single cell or battery of the second aspect of the invention in: electric motors; electric vehicles, including electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), etc.; electric small vehicles, including electric bicycles (E-bikes) and electric scooters (E-scooters); electric golf carts; and power storage systems.

[0027] Another aspect of the invention relates to sulfonamides of formula I:

[0028] ,

[0029] R1 and R2 are independently selected from linear or branched C1-C atoms that can be substituted by one or more fluorine atoms. 12 Alkyl groups, linear or branched C2-C atoms that may be substituted with one or more fluorine atoms. 12 Alkenyl groups, C6-C atoms that can be substituted with one or more fluorine atoms 12 Aryl groups, and CH2CH2O-(CH2CH2O) n-R3, where R3 is methyl or ethyl, and n is an integer from 0 to 20; or R1 and R2 can combine with each other to form a nitrogen-containing aliphatic ring, provided that:

[0030] - R1 and R2 are not both ethyl groups;

[0031] - R1 and R2 are not simultaneously -CH2-CH=CH2; and

[0032] - R1 is an unsubstituted phenyl group and R2 is a methyl group, or vice versa.

[0033] Finally, the present invention also relates to a method for preparing sulfonamides of formula I as defined above, wherein the method comprises reacting a compound of formula Ia with... A solution of the compound of formula Ib is added. In the solution;

[0034] Wherein R1 and R2 are as defined in the preceding aspects of the invention; and

[0035] The method may optionally further include purifying the sulfonamide of Formula I obtained thus as defined above. Attached Figure Description

[0036] Figure 1 Thermogravimetric analysis (TGA) plots of (a) TFSA11, (b) DFSA11, (c) TFSA11 / LiFSI, and (d) DFSA11 / LiFSI.

[0037] Figure 2 Impedance curves of Li symmetric single cells measured at 25°C: TFSA11 / LiFSI (left) and DFSA11 / LiFSI (right).

[0038] Figure 3 The total capacity is 1 mAh cm⁻¹ -2 And the voltage curves of galvanostatic cycling of Li symmetric single cells with varying C-rate at 25°C: TFSA11 / LiFSI (a) and DFSA11 / LiFSI (b). Detailed Implementation

[0039] Unless otherwise stated, all terms used herein shall be understood to have their ordinary meaning as known in the art. Unless a broader definition is provided otherwise, other more specific definitions of certain terms used herein are set forth below and are intended to be applied uniformly throughout the specification and claims.

[0040] Throughout the specification and claims, the word "comprising" and variations thereof are not intended to exclude other technical features, additives, components, or steps. Furthermore, the word "comprising" covers both "consisting of" and "substantially consisting of". Further objects, advantages, and features of the invention will become apparent to those skilled in the art upon examination of the specification or may be learned through practice of the invention.

[0041] Throughout the specification and claims, the terms "blend" and "mixture" will be used interchangeably.

[0042] For the purposes of this invention, any range given includes both the lower and upper endpoints of the range. When a range or value (e.g., temperature, time, molar ratio, volume ratio, etc.) is defined by the term "about" (i.e., having a variation of 5% around the indicated point), it should be considered approximate.

[0043] As mentioned above, a first aspect of the present invention relates to a liquid electrolyte comprising:

[0044] i. At least one sulfonamide having the general formula I,

[0045] ;

[0046] R1 and R2 are independently selected from linear or branched C1-C atoms that can be substituted by one or more fluorine atoms. 12 Alkyl groups, linear or branched C2-C atoms that may be substituted with one or more fluorine atoms. 12 Alkenyl groups, C6-C atoms that can be substituted with one or more fluorine atoms 12 Aryl groups, and CH2CH2O-(CH2CH2O) n -R3, where R3 is methyl or ethyl, and n is an integer from 0 to 20; or R1 and R2 can combine with each other to form a nitrogen-containing aliphatic ring; and

[0047] ii. At least one lithium salt;

[0048] The electrolyte is further characterized in that:

[0049] - The electrolyte does not contain polymers other than sulfonamide-containing polymers, and

[0050] - When the combination of i) and ii) is in solid form, the electrolyte further comprises at least one solvent suitable for dissolving the combination.

[0051] Further embodiments relating to the first aspect of the present invention will be given below.

[0052] sulfonamide

[0053] The liquid electrolyte of the present invention comprises at least one sulfonamide of Formula I as shown above. In the context of this invention, the term "sulfonamide" refers to an organic compound comprising a core functional group >NS(=O)2-, wherein an N atom is connected to two additional organic moieties R1 and R2, and an S atom is further connected to a fragment CHF2. In one particular embodiment, the liquid electrolyte of the present invention comprises one sulfonamide of Formula I; in another particular embodiment, it comprises two or more sulfonamides of Formula I; and in yet another embodiment, it comprises three or more sulfonamides of Formula I.

[0054] In one embodiment, groups R1 and R2 are the same. In another embodiment, groups R1 and R2 are different.

[0055] Typically, groups R1 and R2 are independently selected from linear or branched C1-C groups that can be substituted with one or more fluorine atoms. 12 Alkyl groups, linear or branched C2-C atoms that may be substituted with one or more fluorine atoms. 12 Alkenyl groups, C6-C atoms that can be substituted with one or more fluorine atoms 12 Aryl groups, and CH2CH2O-(CH2CH2O) n -R3, where R3 is methyl or ethyl, and n is an integer from 0 to 20; or R1 and R2 may combine with each other to form a nitrogen-containing aliphatic ring.

[0056] As used in this article, “C1-C” 12 "Alkyl" refers to a branched or linear aliphatic carbon chain consisting of 1 to 12 carbon atoms. C1-C 12 Illustrative examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, hexyl, heptyl, octyl, etc. In preferred embodiments, the aliphatic chain may contain fewer carbon atoms, such as 6 carbon atoms (“C1-C6 alkyl”) or 3 carbon atoms (“C1-C3 alkyl”). Methyl is the most preferred alkyl group. The alkyl chain may be partially or fully fluorinated (“perfluorinated”), which means that at least one, but not all, hydrogen atoms in any CH bond are replaced by fluorine atoms, or that all hydrogen atoms in any CH bond are replaced by fluorine atoms.

[0057] As used in this article, “C2-C” 12 "Alkenyl" refers to a linear or branched aliphatic group having 2 to 12 carbon atoms and at least one C=C double bond. Such alkenyl groups include vinyl (-CH=CH2), n-2-propenyl (allyl, -CH2CH=CH2), etc.

[0058] As used in this article, "C6-C" 12"Aryl" refers to an aromatic hydrocarbon ring containing 6 to 12 carbon atoms, which is also two fused rings, optionally substituted with alkyl groups as defined above, such as phenyl, α-naphthyl, β-naphthyl, m-methylphenyl, p-trifluoromethylphenyl, etc.

[0059] More specifically, R1 and R2 are independently selected from linear or branched C1-C atoms that can be substituted by one or more fluorine atoms. 12 Alkyl groups, linear or branched C2-C atoms that may be substituted with one or more fluorine atoms. 12 Alkenyl groups, and CH2CH2O-(CH2CH2O) n -R3, where R3 is H or methyl, and n is an integer from 0 to 10; or R1 and R2 can combine with each other to form a 3- to 7-membered nitrogen-containing aliphatic ring.

[0060] Preferably, R1 and R2 are independently selected from linear or branched C1-C6 alkyl groups that can be substituted with one or more fluorine atoms, linear or branched C2-C6 alkenyl groups that can be substituted with one or more fluorine atoms, and CH2CH2O-(CH2CH2O). n -R3, where R3 is H or methyl, and n is an integer from 0 to 10; or R1 and R2 can combine with each other to form a 3- to 7-membered nitrogen-containing aliphatic ring.

[0061] More preferably, R1 and R2 are independently selected from linear or branched C1-C6 alkyl, linear or branched C2-C6 alkenyl, and CH2CH2O-(CH2CH2O). n -R3, where R3 is a methyl group and n is an integer from 0 to 5; or R1 and R2 can combine with each other to form a 3- to 7-membered nitrogen-containing aliphatic ring.

[0062] Even more preferably, R1 and R2 are independently selected from linear C1-C6 alkyl, C2-C6 alkenyl and -CH2CH2OCH2CH2O-CH3 groups; or R1 and R2 can be combined with each other to form a 3- to 6-membered nitrogen-containing aliphatic ring.

[0063] Even more preferably, R1 and R2 are selected from linear C1-C3 alkyl, C2-C3 alkenyl, and -CH2CH2O-CH3. More preferably, R1 and R2 are independently linear C1-C3 alkyl.

[0064] In the most preferred embodiment, R1=R2=CH3.

[0065] At least one sulfonamide may be from 5% to 95% by weight of the electrolyte; preferably from 10% to 90% by weight of the electrolyte, more preferably from 50% to 90% by weight of the electrolyte; and even more preferably, at least one sulfonamide is about 88% by weight of the electrolyte.

[0066] The electrolyte of the present invention is further characterized in that it does not contain polymers other than "sulfonamide-containing polymers," which are polymers having a functional group >NS(=O)2- in which the N atom is linked to two additional organic moieties, and the S atom is further linked to another organic moieties. In a particular embodiment, such a "sulfonamide-containing polymer" is a sulfonamide of formula I in which R1 and R2 are defined in such a way that the resulting sulfonamide is a polymer. In another embodiment, the electrolyte of the first aspect of the invention does not contain polymers selected from: sulfonamide-containing polymers, polyalkylene oxides, polyalkylene imides, polyalkylene sulfides, poly(meth)acrylates, polyphosphazenes, polysiloxanes, polyvinyl alcohol (PVA), polyvinylamine (PVAm), polyvinyl acetate (PVAc), polyhalogenated vinylidene fluoride-hexafluoropropylene (PVdF-HFP), polyacrylonitrile (PAN), poly(vinylpyrrolidone) (PVP), poly(2-vinylpyridine), poly(ε-caprolactone) (PCL), polymaleimide, and alternating polymers thereof with olefins, polyaniline (PANI), chitosan (CS), or any blends, copolymers, or crosslinked polymers thereof.

[0067] lithium salts

[0068] The liquid electrolyte may contain at least one lithium salt, which may be an organic lithium salt, an inorganic lithium salt, or a combination thereof.

[0069] Specifically, inorganic lithium salts may include, but are not limited to, LiClO4, LiNO3, LiBF4, LiAsF6, LiPF6, LiBF3Cl, and LiF.

[0070] Organic lithium salts may include, but are not limited to, LiN(SO2CF3)2 (or LiTFSI), LiN(SO2CF3)(SO2CF2H) (or LiDFTFSI), LiN(SO2F)2 (or LiFSI), LiN(SO2CF3)(SO2F), LiN(C2F5SO2)(SO2F), LiB(C2O4)2, LiBF2(C2O4), LiC(SO2CF3)3, LiPF3(C2F5)3, and LiCF3SO3.

[0071] In one embodiment, at least one lithium salt is selected from LiClO4, LiNO3, LiBF4, LiAsF6, LiPF6, LiBF3Cl, LiF, LiN(SO2CF3)2, LiN(SO2CF3)(SO2CF2H), LiN(SO2F)2, LiN(SO2CF3)(SO2F), LiN(C2F5SO2)(SO2F), LiB(C2O4)2, LiBF2(C2O4), LiC(SO2CF3)3, LiPF3(C2F5)3, LiCF3SO3, or combinations thereof.

[0072] In another embodiment, at least one lithium salt is selected from LiN(SO2CF3)2, LiN(SO2CF3)(SO2CF2H), LiN(SO2F)2, LiN(SO2CF3)(SO2F), LiB(C2O4)2, LiBF2(C2O4), LiC(SO2CF3)3, LiPF3(C2F5)3, LiCF3SO3, and LiNO3, or combinations thereof.

[0073] In a preferred embodiment, at least one lithium salt is an organic lithium salt, preferably selected from LiN(SO2CF3)(SO2CF2H), LiB(C2O4)2, LiBF2(C2O4), LiN(SO2F)2, LiN(SO2CF3)2, LiN(SO2CF3)(SO2F), or combinations thereof; more preferably, the organic lithium salt is selected from LiN(SO2CF3)(SO2CF2H), LiN(SO2F)2, LiN(SO2CF3)2, or combinations thereof.

[0074] In a preferred embodiment, the electrolyte contains only one lithium salt. In another embodiment, the lithium salt contained in the liquid electrolyte is LiN(SO2CF3)(SO2CF2H), LiN(SO2F)2, or LiN(SO2CF3)2.

[0075] The at least one lithium salt contained in the liquid electrolyte may vary from 5% to 25% by weight, preferably from 8% to 18% by weight, even more preferably from 10% to 15% by weight, and even more preferably from about 12% by weight, relative to the total weight of the electrolyte.

[0076] In another embodiment of the first aspect of the invention, the electrolyte is further characterized in that it comprises an organic carbonate. In another embodiment of the first aspect of the invention, the electrolyte is further characterized in that it does not contain an organic carbonate. For the purposes of the invention, any carbonate containing an organic, cyclic or linear chain having at least C and H atoms (O=C(-O)) is acceptable. -)2 must be considered an organic carbonate. Organic carbonates are preferably liquids at room temperature. As practical examples, the definition of organic carbonates includes cyclic alkylene carbonates (ethylene carbonate, propylene carbonate, butylene carbonate, etc.) and di(hydrocarbonyl) carbonates such as dialkyl carbonates, diaryl carbonates, alkylaryl carbonates, or mixtures thereof, even though this list is non-limiting.

[0077] In one particular embodiment, the substituted derivatives of the aforementioned organic carbonates are either included in or excluded from the liquid electrolyte of the present invention. One or more substituents may be present on the alkylene, alkyl, or aryl moiety. Non-limiting examples of substituents include halogens, alkoxy groups, hydroxyl groups, nitrogen substituents, phosphorus substituents, sulfur substituents, and similar moieties.

[0078] solvent

[0079] In one particular embodiment, when the combination of i) and ii) is in solid form, the electrolyte of the first aspect of the invention further comprises at least one solvent suitable for dissolving the combination.

[0080] However, in another particular embodiment, the liquid electrolyte composition of the present invention may optionally contain at least one solvent suitable for dissolving the lithium salt of the electrolyte.

[0081] In one particular embodiment, when the electrolyte of the present invention is characterized by not containing carbonate, the solvent cannot be a carbonate-based solvent.

[0082] Examples of solvents are organic solvents, such as dimethoxyethane (DME), 1,2-diethoxyethane (DEE), 1,3-dioxolane (DOL), diethylene glycol dimethyl ether (DEGDME), triethylene glycol dimethyl ether (G3), tetraethylene glycol dimethyl ether (TEGDME), poly(ethylene glycol) dimethyl ether (PEGDME), tetrahydropyran (THP), 4-methyltetrahydropyran, γ-butyrolactone, tetrahydrofuran (THF), 2-methyltetrahydrofuran, diethyl ether, methyl-tert-butyl ether, succinate (SN), glutaronitrile (GN), adiponitrile (AN), N,N-dimethylaminosulfonyl fluoride (FSA), N,N-dimethyltrifluoromethane-sulfonamide (TFSA), and any mixtures thereof.

[0083] When the electrolyte also contains at least one solvent, it is present in an amount ranging from 1% to 50% by weight relative to the total weight of the electrolyte, preferably from 1% to 40% by weight, more preferably from 1% to 30% by weight, and even more preferably from 1% to 20% by weight relative to the total weight of the electrolyte.

[0084] In a preferred embodiment, when the electrolyte also contains at least one solvent:

[0085] - The amount of at least one sulfonamide can range from 5% to 90% by weight of the electrolyte; preferably from 10% to 90% by weight of the electrolyte, more preferably from 50% to 90% by weight of the electrolyte; even more preferably, the at least one sulfonamide is about 88% by weight of the electrolyte.

[0086] - The amount of at least one lithium salt relative to the total weight of the electrolyte can vary from 5% to 25% by weight, preferably from 8% to 18% by weight, even more preferably from 10% to 15% by weight, and even more preferably from about 12% by weight.

[0087] - The amount of at least one solvent may vary from 1% to 70% by weight, preferably from 1% to 50% by weight, or even more preferably from 1% to 25% by weight, relative to the total weight of the electrolyte.

[0088] thermal stability

[0089] The electrolyte of the present invention is characterized by its high thermal stability compared to prior art liquid electrolytes. Specifically, thermal stability can be determined by measuring the mass of the electrolyte over time over a wide temperature range. In one embodiment, the thermal stability of the electrolyte is determined by thermogravimetric analysis (TGA). Specifically, if no mass change is observed at a certain temperature or temperature range, the substance is considered thermally stable at said temperature or temperature range. Specifically, the evaluation range for the electrolyte of the present invention is from room temperature up to 600°C. In a preferred embodiment, the TGA measurement is performed under an inert gas atmosphere. In another preferred embodiment, the heating rate is 10°C / min. -1 In the most preferred embodiment, thermal stability is determined by measuring 10°C per minute under an argon atmosphere and within a range from room temperature up to 600°C. -1 The heating rate was determined by thermogravimetric analysis.

[0090] According to the above embodiments, the electrolyte of the present invention is thermally stable at temperatures up to 150°C, preferably up to 120°C, more preferably up to 90°C, and even more preferably within a range from room temperature up to about 83°C. This improved thermal stability of the electrolyte of the present invention has practical advantages because it can significantly widen the temperature range for the use of electrochemical single cells or batteries including said electrolyte.

[0091] Alternative implementation schemes for electrolytes

[0092] In one embodiment of the present invention, the liquid electrolyte comprises the following:

[0093] i. At least one sulfonamide having general formula I

[0094]

[0095] R1 and R2 are independently selected from linear or branched C1-C atoms that can be substituted by one or more fluorine atoms. 12 Alkyl groups, linear or branched C2-C atoms that may be substituted with one or more fluorine atoms. 12 Alkenyl groups, C6-C atoms that can be substituted with one or more fluorine atoms 12 Aryl groups, and CH2CH2O-(CH2CH2O) n -R3, where R3 is methyl or ethyl, and n is an integer from 0 to 20; or R1 and R2 can combine with each other to form a nitrogen-containing aliphatic ring; and

[0096] i. at least one lithium salt; and

[0097] When the combination of i) and ii) is in solid form, there is at least one additional solvent suitable for dissolving the combination.

[0098] In another embodiment of the invention, the liquid electrolyte comprises the following:

[0099] i. A sulfonamide having the general formula I

[0100]

[0101] R1 and R2 are independently selected from linear or branched C1-C atoms that can be substituted by one or more fluorine atoms. 12 Alkyl groups, linear or branched C2-C atoms that may be substituted with one or more fluorine atoms. 12 Alkenyl groups, C6-C atoms that can be substituted with one or more fluorine atoms 12 Aryl groups, and CH2CH2O-(CH2CH2O) n -R3, where R3 is methyl or ethyl, and n is an integer from 0 to 20; or R1 and R2 can combine with each other to form a nitrogen-containing aliphatic ring; and

[0102] ii. A lithium salt; and

[0103] When the combination of i) and ii) is in solid form, there is at least one additional solvent suitable for dissolving the combination.

[0104] In another embodiment of the invention, the liquid electrolyte comprises the following:

[0105] i. A sulfonamide having the general formula I

[0106]

[0107] R1 and R2 are independently selected from linear or branched C1-C atoms that can be substituted by one or more fluorine atoms. 12 Alkyl groups, linear or branched C2-C atoms that may be substituted with one or more fluorine atoms. 12 Alkenyl groups, C6-C atoms that can be substituted with one or more fluorine atoms 12 Aryl groups, and CH2CH2O-(CH2CH2O) n -R3, where R3 is methyl or ethyl, and n is an integer from 0 to 20; or R1 and R2 may combine with each other to form a nitrogen-containing aliphatic ring;

[0108] i. A lithium salt; and

[0109] ii. A solvent.

[0110] In another embodiment, the liquid electrolyte comprises:

[0111] i. A sulfonamide having the general formula I

[0112]

[0113] R1 and R2 are independently selected from linear or branched C1-C6 alkyl, linear or branched C2-C6 alkenyl, and CH2CH2O-(CH2CH2O). n -R3, where R3 is a methyl group and n is an integer from 0 to 5; or R1 and R2 can combine with each other to form a 3- to 6-membered nitrogen-containing aliphatic ring;

[0114] ii. At least one lithium salt selected from LiClO4, LiNO3, LiBF4, LiAsF6, LiPF6, LiBF3Cl, LiF, LiN(SO2CF3)2, LiN(SO2CF3)(SO2CF2H), LiN(SO2F)2, LiN(SO2CF3)(SO2F), LiN(C2F5SO2)(SO2F), LiB(C2O4)2, LiBF2(C2O4), LiC(SO2CF3)3, LiPF3(C2F5)3, LiCF3SO3, and combinations thereof;

[0115] The electrolyte is further characterized in that it does not contain polymers other than sulfonamide-containing polymers.

[0116] In a specific implementation plan later:

[0117] - The amount of a sulfonamide can range from 5% to 95% by weight of the electrolyte; preferably from 10% to 90% by weight of the electrolyte, more preferably from 50% to 90% by weight of the electrolyte; even more preferably, at least one sulfonamide is about 88% by weight of the electrolyte; and / or

[0118] - The amount of at least one lithium salt may vary from 5% to 25% by weight, preferably from 8% to 18% by weight, even more preferably from 10% to 15% by weight, and even more preferably from about 12% by weight, relative to the total weight of the electrolyte.

[0119] In another embodiment, the liquid electrolyte comprises:

[0120] i. A sulfonamide having the general formula I

[0121] ;

[0122] R1 and R2 are independently selected from linear or branched C1-C6 alkyl, linear or branched C2-C6 alkenyl, and CH2CH2O-(CH2CH2O). n -R3, where R3 is a methyl group and n is an integer from 0 to 5; or R1 and R2 can combine with each other to form a 3- to 6-membered nitrogen-containing aliphatic ring.

[0123] i. At least one lithium salt selected from LiClO4, LiNO3, LiBF4, LiAsF6, LiPF6, LiBF3Cl, LiF, LiN(SO2CF3)2, LiN(SO2CF3)(SO2CF2H), LiN(SO2F)2, LiN(SO2CF3)(SO2F), LiN(C2F5SO2)(SO2F), LiB(C2O4)2, LiBF2(C2O4), LiC(SO2CF3)3, LiPF3(C2F5)3, LiCF3SO3, and combinations thereof; and

[0124] ii. At least one solvent;

[0125] The electrolyte is further characterized in that it does not contain polymers other than sulfonamide-containing polymers of general formula I.

[0126] In a specific implementation plan later:

[0127] - The amount of sulfonamide can range from 5% to 90% by weight of the electrolyte; preferably from 10% to 90% by weight of the electrolyte, more preferably from 50% to 90% by weight of the electrolyte; even more preferably, at least one sulfonamide is about 88% by weight of the electrolyte.

[0128] - The amount of at least one lithium salt relative to the total weight of the electrolyte can vary from 5% to 25% by weight, preferably from 8% to 18% by weight, even more preferably from 10% to 15% by weight, and even more preferably from about 12% by weight; and,

[0129] - The amount of at least one solvent may vary from 1% to 70% by weight, preferably from 1% to 50% by weight, or even more preferably from 1% to 25% by weight, relative to the total weight of the electrolyte.

[0130] In another embodiment, the liquid electrolyte comprises:

[0131] i. Sulfonamides of the following formula

[0132] ;

[0133] ii. Organolithium salts selected from LiN(SO2CF3)(SO2CF2H), LiN(SO2F)2, LiN(SO2CF3)2, or combinations thereof; and

[0134] iii. Optional solvent,

[0135] The weight ratio between sulfonamide and organolithium salt can vary between 80:20 and 95:5; the electrolyte is further characterized in that it does not contain polymers.

[0136] In another embodiment, the liquid electrolyte comprises the following:

[0137] i. Sulfonamides of the following formula

[0138] ;as well as

[0139] ii. Organolithium salts selected from LiN(SO2CF3)(SO2CF2H), LiN(SO2F)2, LiN(SO2CF3)2, or combinations thereof;

[0140] The weight ratio between sulfonamide and organolithium salt can vary between 80:20 and 95:5.

[0141] Electrochemical single cells and batteries

[0142] The electrolyte of the first aspect of the invention is particularly useful in electrochemical devices such as electrochemical single cells or batteries, especially in secondary electrochemical single cells or batteries in which the battery reaction is reversible.

[0143] The second aspect of the invention relates to an electrochemical single cell or battery comprising a liquid electrolyte according to the first aspect of the invention.

[0144] In a preferred embodiment, the second aspect of the invention relates to an electrolyte comprising any embodiment, preferred embodiment, or particular embodiment of the first aspect of the invention as defined above, and further comprising a negative electrode, a positive electrode, and optional separators, of an electrochemical single cell or battery.

[0145] In a preferred embodiment, the second aspect of the invention relates to a lithium metal battery comprising an electrolyte according to any embodiment of the first aspect of the invention as defined above. The lithium metal battery is characterized in that it comprises a negative electrode composed substantially of metallic lithium.

[0146] In another preferred embodiment, a second aspect of the invention relates to a lithium metal battery comprising a positive electrode, wherein the positive electrode material is selected from lithium manganese oxide, lithium nickel oxide, lithium nickel manganese cobalt oxide, lithium nickel manganese oxide, lithium manganese cobalt oxide, lithium copper oxide, lithium copper sulfide, lithium iron phosphate, lithium iron sulfide, lithium manganese iron phosphate, and lithium nickel cobalt aluminum oxide.

[0147] In another preferred embodiment, a second aspect of the invention relates to a lithium metal battery comprising a positive electrode, wherein the positive electrode material is a lithium nickel manganese cobalt oxide, such as LiNi 0.6 Mn 0.2 Co 0.2 O2 (NMC622). The lithium nickel manganese cobalt oxide cathode may additionally contain other additives such as conductive carbon and polymer binders. In one embodiment, the cathode consists of NMC622, carbon black as conductive carbon, and polyvinylidene fluoride (PVdF) as a polymer binder. Preferably, the weight ratio of NMC622:conductive carbon:polymer binder is about 90:5:5.

[0148] In another preferred embodiment, a second aspect of the invention relates to a lithium metal battery further comprising a separator membrane (e.g., a polypropylene membrane, preferably microporous polypropylene) disposed between at least one electrode and an electrolyte, such that lithium cations can flow across the membrane between the electrolyte and the surface of the at least one electrode. In a specific embodiment, the thickness of the separator membrane is from 1 µm to 50 µm, preferably from 15 µm to 35 µm, more preferably about 25 µm. The porosity of the separator membrane can also vary within a range, particularly, the average pore diameter is from 0.001 µm to 0.100 µm, preferably from 0.020 µm to 0.080 µm, more preferably about 0.064 µm.

[0149] In another preferred embodiment, the electrochemical single cell or lithium metal battery of the second aspect of the invention has low resistance at the interface between the electrolyte and the lithium metal electrode. Specifically, the interface resistance can be determined by measuring the electrochemical impedance spectroscopy (EIS) of the electrochemical single cell or lithium metal battery using a potentiostat. More specifically, at 25°C at 10... 6 Hz to 10 -2 Electrochemical impedance spectroscopy is recorded in the Hz range. According to any of the above embodiments, the electrochemical impedance of the electrochemical single cell or lithium metal battery is less than 100 Ω cm⁻¹. 2 Preferably below 75 Ω cm 2 More preferably below 50 Ωcm 2 Even more preferably about 35 Ω cm 2 .

[0150] Applications of electrochemical single cells or batteries

[0151] Electrochemical single cells or batteries incorporating the electrolyte of the present invention can be applied to various electronic devices, including but not limited to: electric motors; electric vehicles, including electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), etc.; electric small vehicles, including electric bicycles (E-bikes) and electric scooters (E-scooters); electric golf carts; power storage systems; and so on.

[0152] Methods for preparing electrolytes

[0153] As defined above, a third aspect of the present invention relates to a method for preparing a liquid electrolyte according to a first aspect of the present invention, the method comprising the following steps:

[0154] (i) Provide at least one lithium salt;

[0155] (ii) Mix at least one sulfonamide of formula I with at least one lithium salt of step (i) to obtain a first mixture;

[0156] (iii) When the first mixture is in solid form, at least one solvent suitable for dissolving the first mixture is added to the first mixture, thereby obtaining a second mixture; and

[0157] (iv) Stir the mixture from step (ii) or (iii).

[0158] In one particular embodiment, steps (i) and (ii) of the above method can be performed using the pure components of the electrolyte (e.g., pure solid or liquid), or alternatively, the components can be dissolved in at least one solvent before or after mixing. The use of at least one solvent is particularly necessary when the mixture of sulfonamide and lithium salt of formula (I) is a solid.

[0159] The term "solid form" is used by technicians to refer to a pure substance or mixture that is solid under standard conditions (i.e., approximately 1 bar of pressure and room temperature (20°C to 25°C)).

[0160] However, when the mixture of at least one sulfonamide of formula (I) and at least one lithium salt is a liquid, at least one solvent may optionally be used.

[0161] Suitable solvents for dissolving at least one lithium salt and / or at least one sulfonamide are readily known to those skilled in the art and are generally polar organic solvents. Examples of organic solvents suitable for dissolving lithium, at least one lithium salt, and / or at least one sulfonamide have been listed above.

[0162] In a preferred embodiment, since sulfonamide is used to dissolve at least one lithium salt, steps (i) to (ii) are carried out by using the pure components (lithium salt and sulfonamide) without additional solvent.

[0163] In another embodiment, the method of the present invention for preparing an electrolyte is carried out by adding a solvent to the first mixture of step (ii) to facilitate the dissolution of at least one lithium salt and / or at least one sulfonamide toward obtaining a liquid electrolyte.

[0164] Preferably, the mixture obtained from step (ii) or (iii) is stirred for a certain period of time to ensure a homogeneous solution (i.e., no visible suspended matter). Stirring is performed magnetically at 100 rpm, 200 rpm, 300 rpm, 400 rpm, 500 rpm, 600 rpm, 700 rpm, 800 rpm, 900 rpm, or 1000 rpm; preferably, stirring is performed in the range of 100 rpm to 500 rpm, and even more preferably at about 300 rpm. Furthermore, the mixture from step (iii) is stirred for at least 5 minutes, at least 15 minutes, at least 30 minutes, at least 1 hour, at least 2 hours, at least 4 hours, at least 6 hours, at least 12 hours, or at least 1 day; preferably, the mixture from step (iii) is stirred for 1 hour to 4 hours, more preferably 2 hours.

[0165] All steps of the above method are carried out at a temperature of 10°C to 30°C, preferably 15°C to 25°C, and even more preferably 20°C to 25°C (room temperature).

[0166] Sulfonamide of Formula I

[0167] As described above, another aspect of the present invention also relates to sulfonamides of formula I:

[0168] ,

[0169] R1 and R2 are independently selected from linear or branched C1-C atoms that can be substituted by one or more fluorine atoms. 12 Alkyl groups, linear or branched C2-C atoms that may be substituted with one or more fluorine atoms. 12 Alkenyl groups, C6-C atoms that can be substituted with one or more fluorine atoms 12 Aryl groups, and CH2CH2O-(CH2CH2O) n -R3, where R3 is methyl or ethyl, and n is an integer from 0 to 20; or R1 and R2 can combine with each other to form a nitrogen-containing aliphatic ring, and

[0170] The condition is

[0171] - R1 and R2 are not both ethyl groups;

[0172] - R1 and R2 are not simultaneously -CH2-CH=CH2; and

[0173] - R1 is an unsubstituted phenyl group and R2 is a methyl group, or vice versa.

[0174] The sulfonamides of Formula I are suitable for use in liquid electrolytes as defined in the first aspect of the invention.

[0175] In one implementation, R1 and R2 are the same. In another implementation, R1 and R2 are different.

[0176] In another embodiment, the sulfonamide of formula I is

[0177] ,

[0178] R1 and R2 are independently selected from linear or branched C1-C atoms that can be substituted by one or more fluorine atoms. 12 Alkyl groups, linear or branched C2-C atoms that may be substituted with one or more fluorine atoms. 12 Alkenyl groups, C6-C atoms that can be substituted with one or more fluorine atoms 12 Aryl groups, and CH2CH2O-(CH2CH2O) n -R3, where R3 is methyl or ethyl, and n is an integer from 0 to 20; or R1 and R2 may combine with each other to form a nitrogen-containing aliphatic ring; and the condition is that R1 and R2 are not simultaneously methyl or ethyl.

[0179] In one particular embodiment, R1 and R2 are independently selected from linear or branched C1-C atoms substituted with one or more fluorine atoms. 12 Alkyl groups, linear or branched C2-C atoms that may be substituted with one or more fluorine atoms. 12 Alkenyl, C6-C substituted with one or more fluorine atoms 12 Aryl groups, and CH2CH2O-(CH2CH2O) n -R3, where R3 is methyl or ethyl, and n is an integer from 0 to 20; or R1 and R2 can combine with each other to form a nitrogen-containing aliphatic ring; and

[0180] The condition is that R1 and R2 are not both ethyl.

[0181] In another specific embodiment, R1 and R2 are independently selected from linear or branched C1-C atoms that can be substituted with one or more fluorine atoms. 12 Alkyl groups, linear or branched C2-C atoms that may be substituted with one or more fluorine atoms. 12 Alkenyl groups, C6-C atoms that can be substituted with one or more fluorine atoms 12 Aryl groups, and CH2CH2O-(CH2CH2O) n -R3, where R3 is methyl or ethyl, and n is an integer from 0 to 20; or R1 and R2 can combine with each other to form a nitrogen-containing aliphatic ring; and

[0182] The conditions are:

[0183] R1 and R2 are not both ethyl groups; and

[0184] When R1 is methyl, then R2 is also methyl.

[0185] More specifically, R1 and R2 in the sulfonamide are independently selected from linear or branched C1-C atoms that can be substituted with one or more fluorine atoms. 12 Alkyl groups, linear or branched C2-C atoms that may be substituted with one or more fluorine atoms. 12 Alkenyl groups, and CH2CH2O-(CH2CH2O) n -R3, where R3 is methyl or ethyl, and n is an integer from 0 to 10; or R1 and R2 may combine with each other to form a nitrogen-containing aliphatic ring; provided that R1 and R2 are not both ethyl.

[0186] In a preferred embodiment, R1 and R2 are independently selected from linear or branched C1-C6 alkyl groups that may be substituted with one or more fluorine atoms, linear or branched C2-C6 alkenyl groups that may be substituted with one or more fluorine atoms, and CH2CH2O-(CH2CH2O). n-R3, where R3 is methyl or ethyl, and n is an integer from 0 to 10; or R1 and R2 can combine with each other to form a 3- to 6-membered nitrogen-containing aliphatic ring; provided that R1 and R2 are not both ethyl.

[0187] In a more preferred embodiment, R1 and R2 are independently selected from linear or branched C1-C6 alkyl, linear or branched C2-C6 alkenyl, and CH2CH2O-(CH2CH2O). n -R3, where R3 is a methyl group and n is an integer from 0 to 5; or R1 and R2 can combine with each other to form a 3- to 6-membered nitrogen-containing aliphatic ring; provided that R1 and R2 are not both ethyl groups.

[0188] In one or even more preferred embodiment, R1 and R2 are independently selected from linear or branched C1-C6 alkyl and linear or branched C2-C6 alkenyl groups; or R1 and R2 may be combined with each other to form a 3- to 6-membered nitrogen-containing aliphatic ring; provided that R1 and R2 are not simultaneously ethyl. Most preferably, R1 and R2 are independently selected from linear or branched C1-C6 alkyl groups, more preferably from linear or branched C1-C3 groups, provided that R1 and R2 are not simultaneously ethyl, and even more preferably, R1 and R2 are methyl.

[0189] In one embodiment, R1 and R2 are independently selected from linear C3-C6 alkyl, C2-C6 alkenyl, and -CH2CH2OCH2CH2O-CH3; or R1 and R2 may be combined with each other to form a 3- to 6-membered nitrogen-containing aliphatic ring.

[0190] In another embodiment, R1 and R2 are selected from methyl, ethyl, n-propyl, isopropyl, C2-C3 alkenyl, and -CH2CH2O-CH3, provided that R1 and R2 are not simultaneously methyl or ethyl.

[0191] Methods for preparing sulfonamides

[0192] The present invention also relates to a method for preparing sulfonamides of formula I as defined in the foregoing aspects of the invention, wherein the method comprises reacting a compound of formula Ia with... A solution of the compound of formula Ib is added. In the solution,

[0193] Wherein R1 and R2 are as defined in any embodiment of the preceding aspects of the invention; and

[0194] The method may optionally further include purifying the sulfonamide of formula I as defined in any of the embodiments of the preceding aspects.

[0195] Preferably, compounds Ia and Ib are dissolved in a solvent before addition. Any solvent can be used to dissolve compounds Ia and Ib, preferably chlorinated solvents (i.e., solvents containing at least one Cl atom), and more preferably dichloromethane (DCM). The preferred concentrations of compounds Ia and Ib in their respective solvents are from 0.001 M to 5.0 M; preferably, the concentrations of compounds Ia and Ib in their respective solvents are each independently from each other from 1.0 M to 2.0 M. In another embodiment, the concentrations of compounds Ia and Ib in their respective solutions are each independently from each other of 0.001 M, 0.005 M, 0.01 M, 0.05 M, 0.1 M, 0.5 M, 1.0 M, 1.5 M, 2.0 M, 2.5 M, 3.0 M, 3.5 M, 4.0 M, 4.5 M, or 5.0 M.

[0196] In one particular embodiment, the compound of formula Ia is subjected to temperatures below room temperature, preferably below 0°C, more preferably below -20°C, and even more preferably below -40°C. A solution of the compound of formula Ib is added. In the solution,

[0197] Wherein R1 and R2 are as defined in any of the embodiments of the preceding aspects of the invention. In a preferred embodiment, compounds Ia and Ib are reacted at a temperature ranging from 0°C to -100°C, preferably from -20°C to -100°C, more preferably from -40°C to -100°C; most preferably, the reaction temperature is about -78°C. Preferably, the solution of Ia is added dropwise.

[0198] After the addition of compound Ia to compound Ib is completed, the mixture is stirred at a temperature below room temperature, preferably below 0°C, more preferably below -20°C, and even more preferably below -40°C. In a preferred embodiment, compounds Ia and Ib are reacted at a temperature ranging from 0°C to -100°C, preferably from -20°C to -100°C, more preferably from -40°C to -100°C; most preferably, the reaction temperature is about -78°C.

[0199] After an appropriate reaction time, the reaction is quenched, preferably by adding water. The reaction time will depend on the specific compound; however, preferred reaction times are at least 1 minute, at least 5 minutes, at least 15 minutes, at least 30 minutes, at least 1 hour, at least 2 hours, at least 3 hours, at least 4 hours, at least 5 hours, and at least 6 hours. More preferably, the reaction time is from 1 minute to 12 hours, from 30 minutes to 10 hours, and from 1 hour to 8 hours.

[0200] Following the above method, sulfonamide of formula I is obtained.

[0201] The method may also include an optional purification step in which the sulfonamide of Formula I is isolated in pure form. The purification step may involve several known techniques, such as organic solvent extraction, solvent evaporation, distillation, and drying.

[0202] Example

[0203] The following examples are intended to illustrate, rather than limit, the disclosed implementations.

[0204] List of abbreviations and acronyms

[0205] LiFSI: Lithium bis(fluorosulfonyl)imide

[0206] TFSA11: N,N-Dimethyltrifluoromethanesulfonamide

[0207] DFSA11: N,N-Dimethyldifluoromethanesulfonamide

[0208] rpm: revolutions per minute

[0209] RT: Room temperature

[0210] Reagents and starting materials

[0211] Purchase and use difluoromethanesulfonyl chloride (Manchester Organics Limited), 2M dimethylamine THF solution (Thermo Scientific), magnesium sulfate (Thermo Scientific), LiFSI (Nippon Shokubai), and dichloromethane (Fisher Scientific) without any prior pretreatment.

[0212] Example 1: N,N-Dimethyldifluoromethanesulfonamide (DFSA11) and N,N-Dimethyltrifluoromethanesulfonamide Preparation of (TFSA11)

[0213]

[0214] Synthesis of DFSA11 A solution of difluoromethanesulfonyl chloride (DFSCl, 1 equivalent) in DCM was added dropwise to a mechanically stirred solution of dimethylamine (3 equivalents) in DCM (2M) at -78°C, and the mixture was stirred at -78°C under an Ar atmosphere. After 6 hours, the reaction was quenched by adding water. The aqueous phase was extracted with DCM (3 × 20 mL), and the combined organic fractions were dried over anhydrous Na₂SO₄. After removing DCM by rotary evaporation, a pale yellow liquid was obtained, which was purified by distillation under reduced pressure to provide DFSA11 as a colorless liquid (yield: 38%). 1H NMR (CDCl3): δ 3.0 (s). 19 F NMR: δ -75 (d).

[0215]

[0216] Synthesis of TFSA11 Trifluoromethanesulfonyl chloride (TFSCl, 1 equivalent) in a solution of dimethylamine (3 equivalents) in DCM (2M) was added dropwise at -78°C, and the mixture was stirred at -78°C under an argon atmosphere. After 3 hours, the reaction was quenched by adding water. The aqueous phase was extracted with DCM, and the combined organic fractions were dried over anhydrous Na₂SO₄. After removing DCM by rotary evaporation, a pale yellow liquid was obtained, which was purified by distillation under reduced pressure to give TFSA11 as a colorless liquid (yield: 38%). 1 H NMR (CDCl3): δ 3.1 (s), 6.2 (t). 19 F NMR: δ -120 (d) ppm.

[0217] Example 2: Preparation of the electrolyte of the present invention and a comparative electrolyte

[0218] Lithium bis(fluorosulfonyl)imine salt LiN(SO₂F)₂ (0.15 g) was placed in a vial, followed by the addition of N,N-dimethyldifluoromethanesulfonamide (DFSA11, 1.10 g, 735 μL), and the mixture was allowed to stand with stirring for approximately 2 hours (300 rpm, room temperature). After this time, the solution appeared homogeneous. For comparative purposes, a liquid electrolyte was prepared following the same procedure using N,N-dimethyltrifluoromethanesulfonamide (TFSA11) instead of N,N-dimethyldifluoromethanesulfonamide (DFSA11). In both cases, the weight and volume ratios of sulfonamide to lithium salt were the same (88 / 12).

[0219] The final electrolyte composition is as follows:

[0220]

[0221] Ionic conductivity was measured by AC impedance spectroscopy using a bipolar submerged single cell (CDC749, Hach Lange sensors, Radiometer Analytical) at LiFSI concentrations of RT and 1 M.

[0222]

[0223] As can be seen from the table above, the ionic conductivity is higher when the electrolyte contains N,N-dimethyldifluoromethanesulfonamide than when the electrolyte contains N,N-dimethyltrifluoromethanesulfonamide.

[0224] Example 3: TGA Measurement

[0225] Thermogravimetric analysis (TGA) was performed on a Netzsch STA 449 F3 system. The TGA was conducted at 10 °C for 1 minute under an argon flow. -1 The heating rates ranged from room temperature to 600°C in the experiments.

[0226] Example 4: Li||Li single cell resistance and constant current cycling

[0227] The interfacial resistance at the interface between the electrolyte and the Li metal electrode was characterized using a Li-symmetric single cell with a Celgard 2500 as the separator in a CR2032 type single cell. A pre-prepared electrolyte solution according to Example 2 was cast onto the separator, and the single cell was sealed using a crimping machine in an argon-filled glove box. The interfacial resistance was measured at 25°C using a VMP3 potentiostat (Biologic) for 10... 6 Hz to 10 -2 The electrochemical impedance spectroscopy (EIS) of a single cell is recorded in the range of Hz.

[0228] Next, a Li-symmetric single cell (Li metal disk area: 1.54 cm²) was tested using a Neware battery tester. 2 Constant current cycling, maintaining 1 mAh cm⁻¹ -2 The constant total capacity, and the current density varies from C / 20 up to 1 C.

Claims

1. A liquid electrolyte, comprising: i. At least one sulfonamide having the general formula I, ， R1 and R2 are independently selected from linear or branched C1-C atoms that can be substituted by one or more fluorine atoms. 12 Alkyl groups, linear or branched C2-C atoms capable of being substituted with one or more fluorine atoms. 12 Alkenyl groups, C6-C atoms that can be substituted with one or more fluorine atoms 12 Aryl groups, and CH2CH2O-(CH2CH2O) n -R3, where R3 is methyl or ethyl, and n is an integer from 0 to 20; or R1 and R2 can combine with each other to form a nitrogen-containing aliphatic ring; and ii. At least one lithium salt; The electrolyte is further characterized in that: - The electrolyte does not contain polymers other than sulfonamide-containing polymers, and - When the combination of i) and ii) is in solid form, the electrolyte further comprises at least one solvent suitable for dissolving the combination.

2. The liquid electrolyte according to claim 1, wherein R1 and R2 in the at least one sulfonamide having general formula I are independently selected from linear or branched C1-C sulfonamides capable of being substituted with one or more fluorine atoms. 12 Alkyl groups, linear or branched C2-C atoms capable of being substituted with one or more fluorine atoms. 12 Alkenyl groups, and CH2CH2O-(CH2CH2O) n -R3, where R3 is methyl or ethyl, and n is an integer from 0 to 10; or R1 and R2 can combine with each other to form a 3- to 7-membered nitrogen-containing aliphatic ring.

3. The liquid electrolyte according to any one of claims 1 or 2, wherein R1 and R2 in the at least one sulfonamide having general formula I are each independently selected from linear C1-C6 alkyl, C2-C6 alkenyl and -CH2CH2OCH2CH2O-CH3; or R1 and R2 can be combined with each other to form a 3- to 6-membered nitrogen-containing aliphatic ring.

4. The liquid electrolyte according to any one of the preceding claims, wherein the at least one sulfonamide accounts for 5% to 95% of the weight of the electrolyte; preferably 10% to 90% of the weight of the electrolyte, more preferably 50% to 90% of the weight of the electrolyte; and even more preferably about 88% of the weight of the electrolyte.

5. The liquid electrolyte according to any one of the preceding claims, wherein the at least one lithium salt is selected from LiClO4, LiNO3, LiBF4, LiAsF6, LiPF6, LiBF3Cl, LiF, LiN(SO2CF3)2, LiN(SO2CF3)(SO2CF2H), LiN(SO2F)2, LiN(SO2CF3)(SO2F), LiN(C2F5SO2)(SO2F), LiB(C2O4)2, LiB F2(C2O4), LiC(SO2CF3)3, LiPF3(C2F5)3, LiCF3SO3, or combinations thereof, of organic or inorganic lithium salts; preferably, the at least one lithium salt is selected from LiN(SO2CF3)(SO2CF2H), LiB(C2O4)2, LiN(SO2F)2, LiN(SO2CF3)2, LiN(SO2CF3)(SO2F), or combinations thereof; more preferably, the at least one lithium salt is LiN(SO2F)2.

6. The liquid electrolyte according to any one of the preceding claims, wherein the amount of the at least one lithium salt is in the range of 5% to 25% by weight, preferably 8% to 18% by weight, even more preferably 10% to 15% by weight, and even more preferably about 12% by weight, relative to the total weight of the electrolyte.

7. The liquid electrolyte according to any one of the preceding claims, comprising: i. Sulfonamides of the following formula ； as well as ii. Organolithium salts selected from LiN(SO2CF3)(SO2CF2H), LiN(SO2F)2, LiN(SO2CF3)2, or combinations thereof; iii. Optional solvent, The weight ratio between the sulfonamide and the organolithium salt can vary between 80:20 and 95:5; the electrolyte is further characterized in that it does not contain any polymer.

8. A method for preparing a liquid electrolyte according to any one of claims 1 to 7, comprising the following steps: (i) Provide at least one lithium salt; (ii) Mix at least one sulfonamide of formula I with at least one lithium salt of step (i) to obtain a first mixture; (iii) When the first mixture is in solid form, at least one solvent suitable for dissolving the first mixture is added to the mixture to obtain a second mixture; and (iv) Stir the mixture from step (ii) or (iii).

9. An electrochemical single cell or battery, comprising an electrolyte, a positive electrode, a negative electrode, and optionally a separator, according to any one of claims 1 to 7.

10. The electrochemical single cell or battery according to claim 9, wherein the negative electrode is composed of lithium metal, and the separator, if present, is composed of a polypropylene film.

11. A sulfonamide of formula I: ， R1 and R2 are independently selected from linear or branched C1-C atoms that can be substituted by one or more fluorine atoms. 12 Alkyl groups, linear or branched C2-C atoms capable of being substituted with one or more fluorine atoms. 12 Alkenyl groups, C6-C atoms that can be substituted with one or more fluorine atoms 12 Aryl groups, and CH2CH2O-(CH2CH2O) n -R3, where R3 is methyl or ethyl, and n is an integer from 0 to 20; or R1 and R2 can combine with each other to form a nitrogen-containing aliphatic ring; The conditions are: - R1 and R2 are not both ethyl groups; - R1 and R2 are not simultaneously -CH2-CH=CH2; and - R1 is an unsubstituted phenyl group and R2 is a methyl group, or vice versa.

12. Use of the sulfonamide of formula I according to claim 11 in a liquid electrolyte.

13. A method for preparing a sulfonamide of formula I according to claim 11, ， The method described herein includes using a compound of formula Ia A solution of the compound of formula Ib is added. In the solution; R1 and R2 are as defined in claim 11.

14. The method of claim 13, wherein the method optionally further comprises purifying the sulfonamide of formula I thus obtained.

15. The use of an electrochemical single cell or battery according to any one of claims 9 or 10 in the following: electric motor; electric vehicle, including electric vehicle (EV), hybrid electric vehicle (HEV), plug-in hybrid electric vehicle (PHEV), etc.; electric small vehicle, including electric bicycle (E-bike) and electric scooter (E-scooter); electric golf cart; or power storage system.

Images