Liquid electrolyte comprising sulfonamide and at least two lithium salts, and uses thereof

Abstract

The present invention relates to a liquid electrolyte comprising: i. at least one sulfonamide with general formula I ii. a combination of at least two lithium salts; and iii. at least one co-solvent and / or one filler; and wherein the liquid electrolyte does not comprise an organic carbonate. The invention also relates to electrochemical cell and uses thereof, and to methods for preparing the liquid electrolyte and electrochemical cell.

Description

(19) *EP004730463A1* (11) EP 4 730 463 A1 (12) EUROPEAN PATENT APPLICATION (43) Date of publication: 22.04.2026 Bulletin 2026 / 17 (21) Application number: 25208510.5 (22) Date of filing: 14.10.2025 (51) International Patent Classification (IPC): H01M 10 / 0525 (2010.01) H01M 10 / 0567 (2010.01) H01M 10 / 0568 (2010.01) H01M 10 / 0569 (2010.01) (52) Cooperative Patent Classification (CPC): H01M 10 / 0567; H01M 10 / 0525; H01M 10 / 0568; H01M 10 / 0569; H01M 2300 / 0037 (84) Designated Contracting States: AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC ME MK MT NL NO PL PT RO RS SE SI SK SM TR Designated Extension States: BA Designated Validation States: GE KH LA MA MD TN (30) Priority: 15.10.2024 EP 24383128 (71) Applicant: Basquevolt S.A.U. 01510 Vitoria-Gasteiz, Álava (ES) (72) Inventors: • PISZCZ, Michal E‑01510 Vitoria-Gasteiz, Álava (ES) • WIZNER, Agnieszka E‑01510 Vitoria-Gasteiz, Álava (ES) • CHAKRABORTY, Saheli E‑01510 Vitoria-Gasteiz, Álava (ES) • GIORDANI, Vincent E‑01510 Vitoria-Gasteiz, Álava (ES) • MARTÍNEZ-IBÁÑEZ, María E‑01510 Vitoria-Gasteiz, Álava (ES) • ARMAND, Michel E‑01510 Vitoria-Gasteiz, Álava (ES) • MEABE, Leire E‑01510 Vitoria-Gasteiz, Álava (ES) • GOUJON, Nicolas E‑01510 Vitoria-Gasteiz, Álava (ES) (74) Representative: ABG Intellectual Property Law, S.L. Avenida de Burgos, 16D Edificio Euromor 28036 Madrid (ES) (54) LIQUID ELECTROLYTE COMPRISING SULFONAMIDE AND AT LEAST TWO LITHIUM SALTS, AND USES THEREOF (57) The present invention relates to a liquid electrolyte comprising: i. at least one sulfonamide with general formula I ii. a combination of at least two lithium salts; and iii. at least one co-solvent and / or one filler; and wherein the liquid electrolyte does not comprise an organic carbonate. The invention also relates to electrochemical cell and uses thereof, and tomethods for preparing the liquid electrolyte and electrochemical cell. EP 4 73 0 46 3 A 1 Processed by Luminess, 75001 PARIS (FR) Description FIELD OF THE INVENTION

[0001] The present invention relates to the field of liquid electrolytes for use in electrochemical cells or batteries. The present invention may find widespread application in energy storage and electronic devices. BACKGROUND

[0002] Lithiummetal batteries (LMBs) arguably represent an attractive technology for energy storage applications due to their high energy density. Commercial batteries primarily use liquid electrolytes (LEs) as the ion-transport media owing to their high ionic conductivity and exceptional wettability with electrodes and separator. On the other hand, solid electrolytes, such as those made of polymers, ceramics or their hybrids, feature a lower conductivity than that of established liquid electrolytes.

[0003] Typical liquid electrolytes are organic carbonates and ethers, such as ethylene carbonate (EC), ethyl methyl carbonate (EMC), 1,2-dimethoxyethane (DME), etc. However, liquid carbonate electrolytes may be associated to high flammability, low thermal stability and sub-optimal electrode-electrolyte interfacial resistance. These issues represent a major obstacle to a practical use of liquid electrolytes in LMBs.

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

[0005] For example, document EP3050872A1 relates to an electrolyte solution comprising a fluorinated sulfonamide according to thegeneral formulaR1‑SO2‑NR2R3aspart of asolvent systemandanelectrolyte salt, however thisdocument teaches that flammable carbonate solvents are essential to solve the corresponding technical problem (e.g., aluminum current collector corrosion) while maintaining high electrolyte conductivity.

[0006] US9065146B2 describes a non-aqueous electrolyte which comprises a non-aqueous organic solvent and a lithium salt dissolved therein, wherein the non-aqueous organic solvent contains at least one compound selected from the group consisting of acid anhydrides and carbonic esters havinganunsaturated bond, and at least one compound selected from the group consisting of sulfonic compounds and fluorine-containing aromatic compounds having 9 carbon atoms or less.

[0007] WO2022216593A1 discloses electrolytes and electrochemical cells which comprise asymmetric sulfonamides, lithium salts and carbonates.

[0008] US8802301B2 refers to ionic liquid compositions as electrolytes for lithium-ion batteries containing an alkyl- sulfonamide or an arylsulfonamide and lithium fluoroalkylsulfonimides or fluoroarylsulfonimides under certain sulfona- mide / lithium salt ratios and with a Tg of the resulting mixture lower than ‑50°C.

[0009] WO2022053881A1discloses an electrolyte composition that comprises one ormore sulfonyl-based solvents for electrolytesused inelectrochemical devices, suchas secondarybatteries. Theelectrolytesmay includeoneormore salts, such as one or more alkali-metal salts, dissolved in said sulfonyl-based solvent system.

[0010] US2024 / 322244describes a liquid electrolyte comprising a lithiumsalt composition, a solvent composition anda diluent composition, wherein the diluent composition includes a fluorinated or non-fluorinated alkane.

[0011] Xue Weijiang et al. (Energy & Environmental Science, 2020, 13(1), 212‑220) describes a liquid electrolyte comprising dimethylsulfamoyl fluoride and a combination of two lithium salts, namely LiFSI and LiPF6 without any co- solvent.

[0012] Despite the advances in the field, electrolyte systems displaying improved safety, stability towards Li-metal anode improved interfacial resistance and / or lead to high conductivity are yet to be discovered. Thus, there is a need in art to developnewelectrolyte systems, particularly liquid electrolytes,which overcome the safety and Li-metal stability issues of state-of-art liquid electrolytes and, at the same time, offer a viable electrochemical performance for widespread application. BRIEF DESCRIPTION OF THE INVENTION

[0013] The present invention relates to liquid electrolyte comprising a sulfonamide, at least two lithium salts and a co- solvent. The inventors have found that suchelectrolyte composition enables thedevelopment of electrochemical cells that display advantageous properties, such as high Li-metal stability, improved safety and improved interfacial resistance without compromising the electrolyte conductivity. In addition to that, the liquid electrolyte of the invention provides electrochemical cells exhibiting superior capacity retention than cells having other liquid electrolytes lacking a co-solvent or having only one lithium salt, with coulombic efficiencies higher than 99%.

[0014] Furthermore, the electrolyte composition is characterized by lacking an organic carbonate, as it has been shown that the presence of said carbonate significantly affects the cyclability of the cell wherein the liquid electrolyte is contained. 2 EP 4 730 463 A1 5 10 15 20 25 30 35 40 45 50 55

[0015] Thus, a first aspect of the invention refers to a liquid electrolyte comprising: i. at least one sulfonamide with general formula I: wherein - R1andR2areeach independently selected froma linearorbranchedC1‑C12alkyl groupwhichmaybesubstituted with one ormore fluorine atom(s), a linear or branchedC2‑C12 alkenyl groupwhichmaybe substitutedwith one or more fluorine atom(s), a C6‑C12 aryl group which may be substituted with one or more fluorine atom(s), 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 be combined with each other to form a nitrogen-containing aliphatic ring; ii. a combination of at least two lithiumsalts, selected from thegroupconsisting of LiClO4, LiNO3, LiBF4, LiAsF6, LiPF6, LiBF3Cl, LiF, LiN(SO2F)2, LiN(SO2CF2H)2, LiN(SO2CF3)2, LiN(SO2CF3)(SO2CF2H), LiN(SO2CF3)(SO2F), LiN(SO2CHF2)(SO2F), LiN(C2F5SO2)(SO2F), LiB(C2O4)2, LiBF2(C2O4), LiC(SO2CF3)3, LiPF3(C2F5)3 and LiCF3SO3; and iii. at least, a. one co-solvent selected from the group consisting of 1,2-bis (2,2-difluoroethoxy) ethane (DF2EO), dimethoxy ethane (DME), 1,2-diethoxyethane (DEE), 1,3-dioxolane (DOL), diethylene glycol dimethyl ether (DEGDME), triethylene glycol dimethyl ether (Triglyme), tetraethylene glycol dimethyl ether (TEGDME), poly(ethylene glycol) dimethyl ether (PEGDME), tetrahydropyran (THP), γ-butyrolactone, tetrahydrofuran (THF), 2-methyltetrahydro- furan,diethylether,methyl-tert-butylether, succinonitrile (SN), glutaronitrile (GN), adiponitrile (AN),N,N-dimethyl- trifluoromethane-sulfonamide (TFSA), N,N-dimethyldifluoromethane-sulfonamide (DFSA), ethylene sulfite (ES), propylene sulfite (PS), di-ethylene sulfite (DES), di-methylsulfite (DMS), triethyl phosphate (TEP), difluor- oethyl acetate (DFEA), methyl difluoroacetate (MDFA), 2‑(2,2,2-trifluoroethoxy)ethyl methyl ether (TEME), 2- methoxyethoxy 2,2 difluroethylether (MDFE), triethyl phosphate (TEP), trimethyl phosphate (TMP), tripropyl phosphate (TPP), methyl formate (MF), methyl acetate (MA), methyl butyrate (MB), ethyl acetate (EA), ethyl propionate (EP), trimethylsilylpropane sulfonate (TMSP), and acetamide of chemical structure R1CONR2R3 where R1 can be F, CF3, CF2H or CFH2, and R2 and R3 can be independently H, ‑(CH2)nCH3, - (CH2)nCF3, ‑(CH2)nF, or ‑(CH2)nCH2F or ‑(CH2)nCHF2 where n = 1‑10; and / or b. one filler selected from the group consisting of fluorobenzene (FPh), 1,2-difluoro benzene, 1,3-difluoro benzene, 1,4-difluorobenzene, anisole, fluoroanisole, tris(2,2,2-trifluoroethyl) orthoformate (TFEO), tetrafluoro 1‑(2,2,2-trifluoroethoxy)ethane (D2), bis(2,2,2-trifluoroethyl)ether (BTFE), 1,1,2,2-tetrafluoroethyl‑2,2,3,3-tetra- fluoropropylether (TTE) and polyoxyethylene alkyl ethers, and wherein the liquid electrolyte does not comprise an organic carbonate.

[0016] Asecondaspect of the invention refers toanelectrochemical cell or battery comprising the liquidelectrolyteof the first aspect of the invention, and a cathode.

[0017] A third aspect of the invention refers to the use of the electrochemical cell or battery of the second aspect, in electricmotors; electric cars, includingelectric vehicles (EV), hybridelectric vehicles (HEV), plug-inhybridelectric vehicles (PHEV), or the like; electric carts, including electric bikes (E-bikes) and electric scooters (E-scooters); electric golf carts; and electric power storage systems.

[0018] A fourth aspect of the invention is directed at a method for preparing the liquid electrolyte of the first aspect comprising the steps of: (i) providing a combination of at least two lithium salts; (ii) mixing at least one sulfonamide of formula I with the salts of step (i); (iii) adding to the mixture at least, a. one co-solvent selected from the group consisting of 1,2-bis (2,2-difluoroethoxy) ethane (DF2EO), dimethoxy 3 EP 4 730 463 A1 5 10 15 20 25 30 35 40 45 50 55 ethane (DME), 1,2-diethoxyethane (DEE), 1,3-dioxolane (DOL), diethylene glycol dimethyl ether (DEGDME), triethylene glycol dimethyl ether (Triglyme), tetraethylene glycol dimethyl ether (TEGDME), poly(ethylene glycol) dimethyl ether (PEGDME), tetrahydropyran (THP), γ-butyrolactone, tetrahydrofuran (THF), 2-methyltetrahydro- furan,diethylether,methyl-tert-butylether, succinonitrile (SN), glutaronitrile (GN), adiponitrile (AN),N,N-dimethyl- trifluoromethane-sulfonamide (TFSA), N,N-dimethyldifluoromethane-sulfonamide (DFSA), ethylene sulfite (ES), propylene sulfite (PS), di-ethylene sulfite (DES), di-methylsulfite (DMS), triethyl phosphate (TEP), difluor- oethyl acetate (DFEA), methyl difluoroacetate (MDFA), 2‑(2,2,2-trifluoroethoxy)ethyl methyl ether (TEME), 2- methoxyethoxy 2,2 difluroethylether (MDFE), triethyl phosphate (TEP), trimethyl phosphate (TMP), tripropyl phosphate (TPP), methyl formate (MF), methyl acetate (MA), methyl butyrate (MB), ethyl acetate (EA), ethyl propionate (EP), trimethylsilylpropane sulfonate (TMSP), and acetamide of chemical structure R1CONR2R3 where R1 can be F, CF3, CF2H or CFH2, and R2 and R3 can be independently H, - (CH2)nCH3, ‑(CH2)nCF3, ‑(CH2)nF, or ‑(CH2)nCH2F or ‑(CH2)nCHF2 where n = 1‑10; and / or b. one filler selected from the group consisting of fluorobenzene (FPh), 1,2-difluoro benzene, 1,3-difluoro benzene, 1,4-difluorobenzene, anisole, fluoroanisole, tris(2,2,2-trifluoroethyl) orthoformate (TFEO), tetrafluoro 1‑(2,2,2,‑trifluoroethoxy)ethane (D2), bis(2,2,2-trifluoroethyl)ether (BTFE), 1,1,2,2,tetrafluoroethyl‑2,2,3,3-tet- rafluoropropylether (TTE) and polyoxyethylene alkyl ethers; and (iv) stirring the resulting mixture.

[0019] Afifthaspectof the invention isdirectedatamethod forpreparing theelectrochemical cell or batteryof thesecond aspect comprising the steps of: (i) providing a cathode for an electrochemical cell or a battery; (ii) providing an anode for an electrochemical cell or a battery; (iii) providing the liquid electrolyte as defined in the first aspect of the invention or in any preferred or particular embodiment thereof; and (iv) coating the surface of the cathode provided in step (i) and of the anode provided in step (ii) with the electrolyte provided in step (iii), being said surfaces optionally covered with a porous separator, prior to coating with the electrolyte, in a manner that the electrolyte is arranged between the cathode and the anode such that lithium cations can flow from the cathode to the anode. DESCRIPTION OF THE FIGURE

[0020] Figure 1 shows the capacity retention vs. cycle number for the Li°∥LFP cells at 25 °C, comprising an electrolyte containinga) amixtureof LiFSI lithiumsalt in FSA11at amolar concentrationof 1.0M (E1); b) LiFSI / LiDFOB lithiumsalts at a molar concentration of 0.95 M and 0.05 M, respectively in a FSA11 / Triglyme in 90 / 10 vol.% ratio of solvents (E2); c) LiFSI / LiDFOB lithium salts at amolar concentration of 0.95Mand 0.05M, respectively in a FSA11 / EC in 90 / 10 vol.% ratio of solvents (E3); and d) LiFSI / LiDFOB lithium salts at a molar concentration of 0.95 M and 0.05 M, respectively in a FSA11 / FEC in 90 / 10 vol.% ratio of solvents (E4). DETAILED DESCRIPTION OF THE INVENTION

[0021] All termsasusedherein in thisapplication, unlessotherwisestated, shall beunderstood in their ordinarymeaning asknown in theart.Othermorespecificdefinitions for certain termsasused in thepresent applicationareasset forthbelow and are intended to apply uniformly throughout the specification and claims unless an otherwise expressly set out definition provides a broader definition.

[0022] Throughout the description and claims the word "comprises" and variations of the word, are not intended to exclude other technical features, additives, components or steps. Furthermore, the word "comprise" encompasses the casesof "consist of" and "consists essentially of". Additional objects, advantagesand featuresof the inventionwill become apparent to those skilled in the art upon examination of the description or may be learned by practice of the invention.

[0023] Throughout the description and claims, the terms "blend(s)" and "mixture(s)" will be used interchangeably.

[0024] For the purposes of the invention, any rangesgiven include both the lower and the upper end-points of the range. Ranges or values given, such as temperatures, times, molar ratio, volume ratio and the like, should be considered approximate when they are defined by the term "about" (i.e. with a 5% margin of variation around indicated point).

[0025] As mentioned above, a first aspect of the invention refers to a liquid electrolyte comprising: i. at least one sulfonamide with general formula I 4 EP 4 730 463 A1 5 10 15 20 25 30 35 40 45 50 55 wherein - R1andR2areeach independently selected froma linearorbranchedC1‑C12alkyl groupwhichmaybesubstituted with one ormore fluorine atom(s), a linear or branchedC2‑C12 alkenyl groupwhichmaybe substitutedwith one or more fluorine atom(s), a C6‑C12 aryl group which may be substituted with one or more fluorine atom(s), 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 be combined with each other to form a nitrogen-containing aliphatic ring; ii. a combination of at least two lithiumsalts, selected from thegroupconsisting of LiClO4, LiNO3, LiBF4, LiAsF6, LiPF6, LiBF3Cl, LiF, LiN(SO2F)2, LiN(SO2CF2H)2, LiN(SO2CF3)2, LiN(SO2CF3)(SO2CF2H), LiN(SO2CF3)(SO2F), LiN(SO2CHF2)(SO2F), LiN(C2F5SO2)(SO2F), LiB(C2O4)2, LiBF2(C2O4), LiC(SO2CF3)3, LiPF3(C2F5)3 and LiCF3SO3; and iii. at least, a. one co-solvent selected from the group consisting of 1,2-bis (2,2-difluoroethoxy) ethane (DF2EO), dimethoxy ethane (DME), 1,2-diethoxyethane (DEE), 1,3-dioxolane (DOL), diethylene glycol dimethyl ether (DEGDME), triethylene glycol dimethyl ether (Triglyme), tetraethylene glycol dimethyl ether (TEGDME), poly(ethylene glycol) dimethyl ether (PEGDME), tetrahydropyran (THP), γ-butyrolactone, tetrahydrofuran (THF), 2-methyltetrahydro- furan,diethylether,methyl-tert-butylether, succinonitrile (SN), glutaronitrile (GN), adiponitrile (AN),N,N-dimethyl- trifluoromethane-sulfonamide (TFSA), N,N-dimethyldifluoromethane-sulfonamide (DFSA), ethylene sulfite (ES), propylene sulfite (PS), di-ethylene sulfite (DES), di-methylsulfite (DMS), triethyl phosphate (TEP), difluor- oethyl acetate (DFEA), methyl difluoroacetate (MDFA), 2‑(2,2,2-trifluoroethoxy)ethyl methyl ether (TEME), 2- methoxyethoxy 2,2 difluroethylether (MDFE), triethyl phosphate (TEP), trimethyl phosphate (TMP), tripropyl phosphate (TPP), methyl formate (MF), methyl acetate (MA), methyl butyrate (MB), ethyl acetate (EA), ethyl propionate (EP), trimethylsilylpropane sulfonate (TMSP), and acetamide of chemical structure R1CONR2R3 where R1 can be F, CF3, CF2H or CFH2, and R2 and R3 can be independently H, ‑(CH2)nCH3, - (CH2)nCF3, ‑(CH2)nF, or ‑(CH2)nCH2F or ‑(CH2)nCHF2 where n = 1‑10; and / or b. one filler selected from the group consisting of fluorobenzene (FPh), 1,2-difluoro benzene, 1,3-difluoro benzene, 1,4-difluorobenzene, anisole, fluoroanisole, tris(2,2,2-trifluoroethyl) orthoformate (TFEO), tetrafluoro 1‑(2,2,2-trifluoroethoxy)ethane (D2), bis(2,2,2-trifluoroethyl)ether (BTFE), 1,1,2,2-tetrafluoroethyl‑2,2,3,3-tetra- fluoropropylether (TTE) and polyoxyethylene alkyl ethers; and wherein the liquid electrolyte does not comprise an organic carbonate. Embodiments regarding the first aspect of the invention will be given below. Sulfonamide

[0026] The liquid electrolyte of the present invention comprises at least one sulfonamide of formula I as shown above. The term"sulfonamide" in thecontextof thepresent inventiondenotesanorganic compoundcontaining thecore functional group >N-S(=O)2‑ where the N atom is attached to organic moieties R1 and R2 while the S atom is further attached to a fluorine (F) atom. In a 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; in yet another embodiment, it comprises three or more sulfonamides of formula I. In a preferred embodiment, the liquid electrolyte of the present invention comprises only one sulfonamide of formula I.

[0027] In an embodiment, the groups R1 and R2 are the same. In another embodiment, the groups R1 and R2 are different.

[0028] Typically, the groups R1 and R2 are each independently selected from a linear or branched C1‑C12 alkyl group which may be substituted with one or more fluorine atom(s), a linear or branched C2‑C12 alkenyl group which may be substituted with one or more fluorine atom(s), a C6‑C12 aryl group which may be substituted with one or more fluorine atom(s), 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 be combined with each other to form a nitrogen-containing aliphatic ring. 5 EP 4 730 463 A1 5 10 15 20 25 30 35 40 45 50 55

[0029] A "C1‑C12 alkyl" as used herein refers to a branched or linear aliphatic carbon chain consisting of 1 to 12 carbon atoms. Illustrative examples of C1‑C12 alkyl groups includemethyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, pentyl, hexyl, heptyl, octyl, etc. In preferred embodiments, the aliphatic chain may comprise less carbon atoms, for example 6 ("C1‑C6alkyl") or 3 ("C1‑C3alkyl") carbonatoms.Methyl groupsare themostpreferredalkyl groups.Thealkyl chainmaybe partially or completely fluorinated ("perfluorinated"), meaning that at least one but not all hydrogen atoms of anyC-H bond is replaced by a fluorine atom or that all hydrogen atoms of any C-H bond is replaced by a fluorine atom, respectively.

[0030] A "C2‑C12 alkenyl" as used herein refers to linear or branched aliphatic groups having from 2 to 12 carbon atoms and having at least 1 double C=C bond. Such alkenyl groups include ethenyl (-CH=CH2), n‑2-propenyl (al- lyl,‑CH2CH=CH2) and the like.

[0031] A"C6‑C12aryl" asusedherein refers to aromatic hydrocarbon rings that contain 6 to12carbonatoms, alsoas two fused rings, optionally substituted with alkyl groups as already defined above, such as phenyl, α-naphthyl, β-naphthyl, m- methylphenyl, p-trifluoromethylphenyl and the like.

[0032] More particularly, R1 andR2 are each independently selected froma linear or branchedC1‑C12 alkyl groupwhich may be substitutedwith one ormore fluorine atom(s), a linear or branchedC2‑C12 alkenyl groupwhichmay be substituted with one or more fluorine atom(s), and CH2CH2O‑(CH2CH2O)n‑R3, wherein R3 is H or a methyl group and n is an integer from0 to 10; or R1 andR2may be combinedwith each other to form a 3‑ to 7-membered nitrogen-containing aliphatic ring.

[0033] Preferably,R1 andR2are each independently selected froma linear or branchedC1‑C6alkyl groupwhichmaybe substitutedwith one ormore fluorine atom(s), a linear or branchedC2‑C6 alkenyl groupwhichmay be substitutedwith one or more fluorine atom(s), and CH2CH2O‑(CH2CH2O)n‑R3, wherein R3 is H or a methyl group and n is an integer from 0 to 10; or R1 and R2 may be combined with each other to form a 3‑ to 7-membered nitrogen-containing aliphatic ring.

[0034] More preferably, R1 andR2 are each independently selected froma linear or branchedC1‑C6alkyl group, a linear or branchedC2‑C6 alkenyl group, andCH2CH2O‑(CH2CH2O)n‑R3, whereinR3 is amethyl group and n is an integer from0 to 5; or R1 and R2 may be combined with each other to form a 3‑ to 7-membered nitrogen-containing aliphatic ring. Even more preferably, R1 andR2 are each independently selected from a linear C1‑C6 alkyl group, a C2‑C6 alkenyl group, and a ‑CH2CH2OCH2CH2O-CH3 group; or R1 and R2 may be combined with each other to form a 3‑ to 6-membered nitrogen- containing aliphatic ring.

[0035] Even more preferably, R1 and R2 are each independently selected from a linear C1‑C3 alkyl group, a C2‑C3 alkenyl group, and ‑CH2CH2O-CH3. More preferably, R1 and are each independently selected from a linear C1‑C3 alkyl group.

[0036] In the most preferred embodiment, R1 = R2 = CH3.

[0037] The at least one sulfonamidemay vary from5 to 95wt.%of theweight of the liquid electrolyte, preferably from10 to 90 wt.% of the weight of the electrolyte, more preferably from 30 to 90 wt.% of the weight of the electrolyte; even more preferably from 50 to 90 wt.% of the weight of the electrolyte; most preferably, from 70 to 90 wt.% of the weight of the electrolyte.

[0038] In a particular embodiment, the electrolyte of the first aspect of the invention does not comprise a polymer selected from the group consisting of sulfonamide-containing polymers, polyalkylene oxides, polyalkylenimines, poly- alkylene sulphides, poly(meth)acrylates, polyphosphazenes, polysiloxanes, polyvinyl alcohol (PVA), polyvinyl amine (PVAm), polyvinyl acetate (PVAc), polyvinyl halides, polyvinylidene difluoride-hexafluropropylene (PVdF-HFP), poly- acrylonitrile (PAN), poly(vinylpyrrolidone) (PVP), poly(2-vinylpyridine), poly(ε-caprolactone) (PCL), polymaleimides and their alternate polymerswith alkenes, polyaniline (PANI), chitosan (CS), or anyblendor any copolymer or any cross-linked polymer thereof. Lithium salts

[0039] The liquid electrolyte of the invention comprises a combination of at least two lithium salts, preferably comprising at least the lithium salt LiFSI, of formula

[0040] In the present invention, the liquid electrolyte comprises a combination of at least two lithium salts, selected from the group consisting of LiClO4, LiNO3, LiBF4, LiAsF6, LiPF6, LiBF3Cl, LiF, LiN(SO2F)2, LiN(SO2CF2H)2, LiN(SO2CF3)2, LiN(SO2CF3)(SO2CF2H), LiN(SO2CF3)(SO2F), LiN(SO2CHF2)(SO2F), LiN(C2F5SO2)(SO2F), LiB(C2O4)2, LiBF2(C2O4), LiC(SO2CF3)3, LiPF3(C2F5)3 and LiCF3SO3.

[0041] In an embodiment, the combination of at least two lithium salts is selected from LiClO4, LiNO3, LiBF4, LiAsF6, 6 EP 4 730 463 A1 5 10 15 20 25 30 35 40 45 50 55 LiPF6, LiBF3Cl, LiF, LiN(SO2F)2, LiN(SO2CF3)2, LiN(SO2CF3)(SO2CF2H), LiN(SO2CF3)(SO2F), LiN(C2F5SO2)(SO2F), LiB(C2O4)2, LiBF2(C2O4), LiC(SO2CF3)3, LiPF3(C2F5)3, LiCF3SO3.

[0042] In another embodiment, the combination of at least two lithium salts is selected fromLiN(SO2F)2, LiN(SO2CF3)2, LiN(SO2CF3)(SO2CF2H), LiN(SO2CF3)(SO2F), LiB(C2O4)2, LiBF2(C2O4), LiC(SO2CF3)3, LiPF3(C2F5)3, LiCF3SO3, and LiNO3.

[0043] In a preferred embodiment, the combination of at least two lithium salts is selected from LiN(SO2F)2, LiN(SO2CF3)(SO2CF2H), LiB(C2O4)2, LiBF2(C2O4), LiN(SO2CF3)2, and LiN(SO2CF3)(SO2F); more preferably selected from LiN(SO2F)2, LiN(SO2CF3)(SO2CF2H), LiB(C2O4)2, LiBF2(C2O4), LiN(SO2CF3)2, and LiN(SO2CF3)(SO2F); even more preferably, selected from LiN(SO2F)2, LiN(SO2CF3)(SO2CF2H), LiN(SO2CF3)2, and LiBF2(C2O4).

[0044] Inamostpreferredembodiment, thecombinationofat least two lithiumsalts is LiN(SO2F)2andLiBF2(C2O4), also known as LiFSI and LiDFOB, respectively.

[0045] In a particular embodiment, the at least two lithiumsalts comprised in the liquid electrolyte vary from5 to 45wt.%, preferably from 5 to 40 wt.%, more preferably from 5 to 25 wt.%, evenmore preferably from 8 to 18 wt.%, most preferably from 10 to 15 wt.%, even most preferably is about 12 wt.% with respect to the total weight of the electrolyte. Organic carbonate

[0046] The electrolyte of the invention is further characterized in that it does not comprise an organic carbonate. For the purpose of the invention, any carbonate O=C(-O-)2 that contains an organic, cyclic or linear chain with at least C and H atoms has to be considered an organic carbonate. The organic carbonate is preferably a liquid at room temperature. As practical examples, the definition of organic carbonates includes, even though the list is non-limiting, cyclic alkylene carbonates (ethylene carbonate, propylene carbonate, butylene carbonate and the likes) and di(hydrocarbyl) carbonates, such as dialkyl carbonates, diaryl carbonates, alkyl aryl carbonates or mixtures thereof.

[0047] Substituted derivatives of the aforementioned organic carbonates are also excluded from the liquid electrolyte of this invention. One or more substituents may be present on the alkylene, alkyl or aryl moieties. Non-limiting examples of substituents includehalogen, alkoxy, hydroxyl, nitrogensubstituents, phosphorous substituents, sulphur substituentsand similar moieties.

[0048] Asderivable from theexamplesbelow, thepresenceof carbonates in the liquid electrolyte composition adversely affects cyclability of the cell where it is incorporated, with a marked drop observed after 50 cycles. Co-solvent and / or filler

[0049] The liquid electrolyte of the first aspect of the invention further comprises at least one of a co-solvent or a filler.

[0050] The co-solvent is selected from the group consisting of 1,2-bis (2,2-difluoroethoxy) ethane (DF2EO), dimethoxy ethane (DME), 1,2-diethoxyethane (DEE), 1,3-dioxolane (DOL), diethylene glycol dimethyl ether (DEGDME), triethylene glycol dimethyl ether (Triglyme), tetraethylene glycol dimethyl ether (TEGDME), poly(ethylene glycol) dimethyl ether (PEGDME), tetrahydropyran (THP), γ-butyrolactone, tetrahydrofuran (THF), 2-methyltetrahydrofuran, diethylether, methyl-tert-butylether, succinonitrile (SN), glutaronitrile (GN), adiponitrile (AN), N,N-dimethyltrifluoromethane-sulfona- mide (TFSA), N,N-dimethyldifluoromethane-sulfonamide (DFSA), ethylene sulfite (ES), propylene sulfite (PS), di-ethy- lene sulfite (DES), di-methylsulfite (DMS), triethyl phosphate (TEP), difluoroethyl acetate (DFEA), methyl difluoroacetate (MDFA), 2‑(2,2,2-trifluoroethoxy)ethyl methyl ether (TEME), 2-methoxyethoxy 2,2 difluroethylether (MDFE), triethyl phosphate (TEP), trimethyl phosphate (TMP), tripropyl phosphate (TPP), methyl formate (MF), methyl acetate (MA), methyl butyrate (MB), ethyl acetate (EA), ethyl propionate (EP), trimethylsilylpropane sulfonate (TMSP), andacetamideof chemical structure R1CONR2R3 where R1 can be F, CF3, CF2H or CFH2, and R2 and R3 can be independently H, ‑(CH2)nCH3, ‑(CH2)nCF3, ‑(CH2)nF, or - (CH2)nCH2F or ‑(CH2)nCHF2 where n = 1‑10, and any mixtures thereof.

[0051] In thecontext of the invention, the term "co-solvent" refers toasubstancesuitable for dissolving the lithiumsalts in the electrolyte.

[0052] In a particular embodiment, when the electrolyte is characterized in that it does not comprise a carbonate, the electrolyte does not comprise a carbonate-based solvent.

[0053] In a particular embodiment, the co-solvent is selected from the group consisting of 1,2-bis (2,2-difluoroethoxy) ethane (DF2EO), dimethoxy ethane (DME), 1,2-diethoxyethane (DEE), 1,3-dioxolane (DOL), diethylene glycol dimethyl ether (DEGDME), triethylene glycol dimethyl ether (Triglyme), tetraethylene glycol dimethyl ether (TEGDME), poly(ethy- lene glycol) dimethyl ether (PEGDME), tetrahydropyran (THP), γ-butyrolactone, tetrahydrofuran (THF), 2-methyltetrahy- drofuran, diethylether, methyl-tert-butylether, succinonitrile (SN), glutaronitrile (GN), adiponitrile (AN), N,N-dimethyltri- fluoromethane-sulfonamide (TFSA), ethylene sulfite (ES), propylene sulfite (PS), di-ethylene sulfite (DES), di-methyl- sulfite (DMS), triethyl phosphate (TEP), difluoroethyl acetate (DFEA), methyl difluoroacetate (MDFA), 2‑(2,2,2-trifluor- oethoxy)ethyl methyl ether (TEME), 2-methoxyethoxy 2,2 difluroethylether (MDFE), triethyl phosphate (TEP), trimethyl phosphate (TMP), tripropyl phosphate (TPP), methyl formate (MF), methyl acetate (MA), methyl butyrate (MB), ethyl 7 EP 4 730 463 A1 5 10 15 20 25 30 35 40 45 50 55 acetate (EA), ethyl propionate (EP), trimethylsilylpropane sulfonate (TMSP), and mixtures thereof.

[0054] In a preferred embodiment, the co-solvent is selected from the group consisting of triglyme, ethylene sulfite, and mixtures thereof.

[0055] In a particular embodiment, the co-solvent is present in an amount ranging from 1 to 50 wt% with respect to the totalweight of theelectrolyte, preferably from1 to40wt%,morepreferably from1 to30wt%,evenmorepreferably from1 to 20 wt%, and most preferably from 1 to 10 wt%, with respect to the total weight of the electrolyte.

[0056] In a preferred embodiment: - the amount of the at least one sulfonamidemay vary from 5 to 95wt.% of the weight of the electrolyte; preferably from 10 to 90wt.% of the weight of the electrolyte; more preferably from 30 to 90 wt.% of the weight of the electrolyte; even more preferably from50 to 90wt.%of theweight of the electrolyte;most preferably, from70 to 90wt.%of theweight of the electrolyte; - the amount of the at least two lithium salts may vary from 5 to 45 wt.%, preferably from 5 to 40 wt.%, more preferably from5 to 25wt.%, evenmorepreferably from8 to 18wt.%,most preferably from10 to 15wt.%, evenmost preferably is about 12 wt.% with respect to the total weight of the electrolyte; and, - the amount of the at least one co-solvent may vary from 1 to 50 wt.%, preferably from 1 to 40 wt.%, more preferably from1 to30wt%,evenmorepreferably from1 to20wt%,andmost preferably from1 to10wt%,with respect to the total weight of theelectrolyte. In the context of the present invention, "fillers" donot necessarily dissolve the lithiumsalts but rather deliver additional benefits such as improved wettability of the electrodes that are comprised in the electro- chemical cell or battery. Examples of fillers are known in the art and include, among others: fluorobenzene (FPh), 1,2- difluoro benzene, 1,3-difluoro benzene, 1,4-difluorobenzene, anisole, fluoroanisole, tris(2,2,2-trifluoroethyl) ortho- formate (TFEO), tetrafluoro 1‑(2,2,2-trifluoroethoxy)ethane (D2), bis(2,2,2-trifluoroethyl)ether (BTFE), 1,1,2,2-tetra- fluoroethyl‑2,2,3,3-tetrafluoropropylether (TTE) and polyoxyethylene alkyl ethers.

[0057] In another preferred embodiment: - the amount of the at least one sulfonamidemay vary from 5 to 95wt.% of the weight of the electrolyte; preferably from 10 to 90wt.% of the weight of the electrolyte; more preferably from 30 to 90 wt.% of the weight of the electrolyte; even more preferably from50 to 90wt.%of theweight of the electrolyte;most preferably, from70 to 90wt.%of theweight of the electrolyte; - the amount of the at least two lithium salts may vary from 5 to 45 wt.%, preferably from 5 to 40 wt.%, more preferably from5 to 25wt.%, evenmorepreferably from8 to 18wt.%,most preferably from10 to 15wt.%, evenmost preferably is about 12 wt.% with respect to the total weight of the electrolyte; and, - the amount of the at least one fillermay vary from1 to 50wt.%, preferably from1 to 40wt.%,more preferably from1 to 30wt%,evenmorepreferably from1 to20wt%,andmostpreferably from1 to10wt%,with respect to the totalweight of the electrolyte. Further additives

[0058] In a particular embodiment, the liquid electrolyte of the first aspect of the invention further comprises additives such as scavengers for HF and water, and / or flame retardants. In a particular embodiment, the scavenger is Lithium hexamethyldisilazide (LiHMDS). This is particular useful in the formation of an (electro)chemical robust cathode| electrolyte interphase (CEI).

[0059] In another particular embodiment, the flame retardant is selected from the group consisting of Hexafluorocyclo- triphosphazene (HFPN), Ethoxy (pentafluoro) cyclotriphosphazene (PFPN), ammonium polyphosphate, melamine polyphosphate, pentaerythritol phosphate, piperazine pyrophosphate, aluminum diethyl hypophosphite, aluminum hypophosphite, aluminum phosphate, calcium borate, zinc borate, magnesium borate, aluminum borate, silicon dioxide, metakaolin, sepiolite, mica, zeolite, montmorillonite, glass powder and combinations thereof, preferably Hexafluorocy- clotriphosphazene (HFPN), Ethoxy (pentafluoro) cyclotriphosphazene (PFPN), and combinations thereof. Advantages

[0060] The electrolyte of the invention is characterized in that it exhibits an exceptional compatibility with Li metal, significantly improved safety and enhanced performance due to improved ionic conductivity even at low temperatures. Additionally, the electrolyte of the invention is much less corrosive to the battery components prolonging the life of the battery. Further advantages are found throughout this text, including the example section. 8 EP 4 730 463 A1 5 10 15 20 25 30 35 40 45 50 55 Further embodiments of the electrolyte

[0061] In a particular embodiment, the electrolyte of the invention comprises: i. at least one sulfonamide with general formula I wherein - R1andR2areeach independently selected froma linearorbranchedC1‑C12alkyl groupwhichmaybesubstituted with one ormore fluorine atom(s), a linear or branchedC2‑C12 alkenyl groupwhichmaybe substitutedwith one or more fluorine atom(s), a C6‑C12 aryl group which may be substituted with one or more fluorine atom(s), 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 be combined with each other to form a nitrogen-containing aliphatic ring; ii. a combination of at least two lithiumsalts, selected from thegroupconsisting of LiClO4, LiNO3, LiBF4, LiAsF6, LiPF6, LiBF3Cl, LiF, LiN(SO2F)2, LiN(SO2CF2H)2, LiN(SO2CF3)2, LiN(SO2CF3)(SO2CF2H), LiN(SO2CF3)(SO2F), LiN(SO2CHF2)(SO2F), LiN(C2F5SO2)(SO2F), LiB(C2O4)2, LiBF2(C2O4), LiC(SO2CF3)3, LiPF3(C2F5)3 and LiCF3SO3; iii. at least one co-solvent selected from the group consisting of 1,2-bis (2,2-difluoroethoxy) ethane (DF2EO), dimethoxy ethane (DME), 1,2-diethoxyethane (DEE), 1,3-dioxolane (DOL), diethylene glycol dimethyl ether (DEGDME), triethylene glycol dimethyl ether (Triglyme), tetraethylene glycol dimethyl ether (TEGDME), poly(ethy- lene glycol) dimethyl ether (PEGDME), tetrahydropyran (THP), γ-butyrolactone, tetrahydrofuran (THF), 2-methylte- trahydrofuran, diethylether, methyl-tert-butylether, succinonitrile (SN), glutaronitrile (GN), adiponitrile (AN), N,N- dimethyltrifluoromethane-sulfonamide (TFSA), N,N-dimethyldifluoromethane-sulfonamide (DFSA), ethylene sulfite (ES), propylene sulfite (PS), di-ethylene sulfite (DES), di-methylsulfite (DMS), triethyl phosphate (TEP), difluoroethyl acetate (DFEA), methyl difluoroacetate (MDFA), 2‑(2,2,2-trifluoroethoxy)ethyl methyl ether (TEME), 2-methox- yethoxy 2,2 difluroethylether (MDFE), triethyl phosphate (TEP), trimethyl phosphate (TMP), tripropyl phosphate (TPP), methyl formate (MF), methyl acetate (MA), methyl butyrate (MB), ethyl acetate (EA), ethyl propionate (EP), trimethylsilylpropane sulfonate (TMSP), and acetamide of chemical structure R1CONR2R3 where R1 can be F, CF3, CF2H or CFH2, and R2 and R3 can be independently H, ‑(CH2)nCH3, ‑(CH2)nCF3, ‑(CH2)nF, or ‑(CH2)nCH2F or ‑(CH2)nCHF2 where n = 1‑10, and any mixtures thereof; and iv. optionally, a filler selected from the group consisting of fluorobenzene (FPh), 1,2-difluoro benzene, 1,3-difluoro benzene, 1,4-difluorobenzene, anisole, fluoroanisole, tris(2,2,2-trifluoroethyl) orthoformate (TFEO), tetrafluoro 1‑(2,2,2,‑trifluoroethoxy)ethane (D2), bis(2,2,2-trifluoroethyl)ether (BTFE), 1,1,2,2,tetrafluoroethyl‑2,2,3,3-tetra- fluoropropylether (TTE) and polyoxyethylene alkyl ethers; and wherein the liquid electrolyte does not comprise an organic carbonate.

[0062] In a preferred embodiment, the electrolyte of the invention comprises: i. at least one sulfonamide with general formula I wherein 9 EP 4 730 463 A1 5 10 15 20 25 30 35 40 45 50 55 - R1 and R2 are each independently selected from a linear C1‑C3 alkyl group, a C2‑C3 alkenyl group, and ‑CH2CH2O-CH3; ii. a combination of at least two lithium salts, selected fromLiN(SO2F)2, LiN(SO2CF3)(SO2CF2H), LiN(SO2CF3)2, and LiBF2(C2O4); iii. at least one co-solvent selected from the group consisting of triglyme, ethylene sulfite, and mixtures thereof; and iv. optionally, a filler selected from the group consisting of fluorobenzene (FPh), 1,2-difluoro benzene, 1,3-difluoro benzene, 1,4-difluorobenzene, anisole, fluoroanisole, tris(2,2,2-trifluoroethyl) orthoformate (TFEO), tetrafluoro 1‑(2,2,2,‑trifluoroethoxy)ethane (D2), bis(2,2,2-trifluoroethyl)ether (BTFE), 1,1,2,2,tetrafluoroethyl‑2,2,3,3-tetra- fluoropropylether (TTE) and polyoxyethylene alkyl ethers; and the liquid electrolyte does not comprise an organic carbonate.

[0063] In a more preferred embodiment, the electrolyte of the invention comprises: i. N,N-dimethylsulfamoyl fluoride; ii. a combination of the lithium salt LiFSI and LiBF2(C2O4); and iii. at least one co-solvent selected from the group consisting of triglyme, ethylene sulfite, and mixtures thereof; and iv. optionally, a filler selected from the group consisting of fluorobenzene (FPh), 1,2-difluoro benzene, 1,3-difluoro benzene, 1,4-difluorobenzene, anisole, fluoroanisole, tris(2,2,2-trifluoroethyl) orthoformate (TFEO), tetrafluoro 1‑(2,2,2,‑trifluoroethoxy)ethane (D2), bis(2,2,2-trifluoroethyl)ether (BTFE), 1,1,2,2,tetrafluoroethyl‑2,2,3,3-tetra- fluoropropylether (TTE) and polyoxyethylene alkyl ethers; and wherein the liquid electrolyte does not comprise an organic carbonate.

[0064] In yet another preferred embodiment, the electrolyte of the invention comprises: i. N,N-dimethylsulfamoyl fluoride; ii. a combination of the lithium salt LiFSI and LiBF2(C2O4); and iii. at least one filler selected from the group consisting of fluorobenzene (FPh), 1,2-difluoro benzene, 1,3-difluoro benzene, 1,4-difluorobenzene, anisole, fluoroanisole, tris(2,2,2-trifluoroethyl) orthoformate (TFEO), tetrafluoro 1‑(2,2,2,‑trifluoroethoxy)ethane (D2), bis(2,2,2-trifluoroethyl)ether (BTFE), 1,1,2,2,tetrafluoroethyl‑2,2,3,3-tetra- fluoropropylether (TTE) and polyoxyethylene alkyl ethers; and iv. optionally, a co-solvent selected from the group consisting of triglyme, ethylene sulfite, and mixtures thereof; and wherein the liquid electrolyte does not comprise an organic carbonate Electrochemical cell and battery

[0065] The electrolyte of the first aspect of the invention is particularly useful in electrochemical devices such as electrochemical cells or batteries, particularly secondary electrochemical cells or batteries wherein the cell reactions are reversible.

[0066] The secondaspect of the invention relates to an electrochemical cell or a battery comprising the liquid electrolyte according to the first aspect of the invention.

[0067] In a preferred embodiment, the second aspect of the invention relates to an electrochemical cell or a battery comprising the electrolyte according to any, preferred or particular, embodiment of the first aspect of the invention defined above, and further comprising an anode, a cathode and, optionally, a separator.

[0068] In a preferred embodiment, the second aspect of the invention relates to a lithium metal battery comprising the electrolyte according to any embodiment of the first aspect of the invention defined above. A lithium metal battery is a battery characterized in that it comprises an anode consisting essentially of metallic lithium.

[0069] Ina further preferredembodiment, thesecondaspect of the invention relates toa lithiummetal battery comprising a cathode wherein the cathode material is selected from the group consisting of lithium manganese oxide, lithium nickel oxide, lithium nickel manganese cobalt oxide, lithium nickel manganese oxide, lithium manganese cobalt oxide, lithium copperoxide, lithiumcoppersulphide, lithium ironphosphate, lithium ironsulphide, lithiummanganese ironphosphateand lithium nickel cobalt aluminium oxide. In a further preferred embodiment, the second aspect of the invention relates to a lithiummetal battery comprising a cathodewherein the cathodematerial is lithiumnickelmanganese cobalt oxide such as LiNi0.6Mn0.2Co0.2O2 (NMC622), lithium iron phosphate LiFePO4 (LFP) and a lithium manganese iron phosphate LiFexMn1-xPO4, wherein x < 1 (LMFP). In a more preferred embodiment, the cathode is LFP.

[0070] The cathodemay additionally contain other additives, such as a conductive carbon and a polymeric binder. In an embodiment, the cathode further comprises a conductive carbon selected from the group consisting of carbon black (for 10 EP 4 730 463 A1 5 10 15 20 25 30 35 40 45 50 55 example Super P®), carbon nanotubes, and mixtures thereof. In another particular embodiment, the cathode further comprises polyvinylidene fluoride (PVdF) as a polymeric binder. It is preferred that the weight ratio between LFP : conductive carbon: polymeric binder is about 96.5:1.5:2.

[0071] In a further preferred embodiment, the second aspect of the invention relates to a lithium metal battery further comprisingaseparator, preferably aporousseparator, arrangedbetweenat least oneelectrodeand theelectrolyte in such a configuration that lithium cations can flow across said separator between the electrolyte and the surface of said at least one electrode.

[0072] Examples of suitable separators are known to the skilled person, and include polypropylene membranes, preferably microporous polypropylene membranes, or ceramic materials. A preferred separator is Celgard® H2010 (a 20 µm trilayer microporous membrane PP / PE / PP).

[0073] In specific embodiments, the separator hasa thicknessof between1and50µm,preferably of between15and35 µm,more preferably of about 20µm. The porosity of the separatormay also vary between a certain range, particularly the average pore diameter is comprised between 0.001 and 0.100 µm, preferably between 0.020 and 0.080 µm, more preferably is about 0.064 µm.

[0074] In a particular embodiment, the electrochemical cell of the first aspect of the invention comprises an anode, preferably a lithium metal anode.

[0075] In a further preferred embodiment, the electrochemical cell or lithium metal battery of the second aspect of the invention has a low resistance at the interface between the electrolyte and lithium metal electrode. In particular, the interfacial resistance may be determined by measuring electrochemical impedance spectra (EIS) of the electrochemical cell or lithium metal battery using a potentiostat. More particularly, electrochemical impedance spectra recorded in the range from 106 to 10‑2 Hz at 25 °C. According to any of the above embodiments, the electrochemical cell or lithiummetal battery has an electrochemical impedance lower than 100Ω cm2, preferably lower than 75Ω cm2, more preferably lower than 50 Ω cm2, even more preferably of about 35 Ω cm2. Uses of the electrochemical cell of the invention

[0076] The electrochemical cell of the inventionmay be applied to a variety of electronic deviceswhichmay include, but are not limited to: electric motors; electric cars, including electric vehicles (EV), hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEV), or the like; electric carts, including electric bikes (E-bikes) and electric scooters (E- scooters); electric golf carts; electric power storage systems; or the like. Methods for preparing the electrolyte

[0077] In a fourth aspect, the invention is directedat amethod for preparing the liquid electrolyte comprising the steps of: (i) providing a combination of at least two lithium salts; (ii) mixing at least one sulfonamide of formula I with the salts of step (i); (iii) adding to the mixture, at least a. one co-solvent selected from the group consisting of 1,2-bis (2,2-difluoroethoxy) ethane (DF2EO), dimethoxy ethane (DME), 1,2-diethoxyethane (DEE), 1,3-dioxolane (DOL), diethylene glycol dimethyl ether (DEGDME), triethylene glycol dimethyl ether (Triglyme), tetraethylene glycol dimethyl ether (TEGDME), poly(ethylene glycol) dimethyl ether (PEGDME), tetrahydropyran (THP), γ-butyrolactone, tetrahydrofuran (THF), 2-methyltetrahydro- furan,diethylether,methyl-tert-butylether, succinonitrile (SN), glutaronitrile (GN), adiponitrile (AN),N,N-dimethyl- trifluoromethane-sulfonamide (TFSA), N,N-dimethyldifluoromethane-sulfonamide (DFSA), ethylene sulfite (ES), propylene sulfite (PS), di-ethylene sulfite (DES), di-methylsulfite (DMS), triethyl phosphate (TEP), difluor- oethyl acetate (DFEA), methyl difluoroacetate (MDFA), 2‑(2,2,2-trifluoroethoxy)ethyl methyl ether (TEME), 2- methoxyethoxy 2,2 difluroethylether (MDFE), triethyl phosphate (TEP), trimethyl phosphate (TMP), tripropyl phosphate (TPP), methyl formate (MF), methyl acetate (MA), methyl butyrate (MB), ethyl acetate (EA), ethyl propionate (EP), trimethylsilylpropane sulfonate (TMSP), and acetamide of chemical structure R1CONR2R3 where R1 can be F, CF3, CF2H or CFH2, and R2 and R3 can be independently H, - (CH2)nCH3, ‑(CH2)nCF3, ‑(CH2)nF, or ‑(CH2)nCH2F or ‑(CH2)nCHF2 where n = 1‑10; and / or b. a filler selected from the group consisting of fluorobenzene (FPh), 1,2-difluoro benzene, 1,3-difluoro benzene, 1,4-difluorobenzene, anisole, fluoroanisole, tris(2,2,2-trifluoroethyl) orthoformate (TFEO), tetrafluoro 1‑(2,2,2,‑trifluoroethoxy)ethane (D2), bis(2,2,2-trifluoroethyl)ether (BTFE), 1,1,2,2,tetrafluoroethyl‑2,2,3,3-tet- rafluoropropylether (TTE) and polyoxyethylene alkyl ethers; and (iv) stirring the resulting mixture. 11 EP 4 730 463 A1 5 10 15 20 25 30 35 40 45 50 55

[0078] In a particular embodiment, steps (i) and (ii) of the method above may be performed by using the neat components of the electrolyte (e.g. the neat solid or liquid) or, alternatively, said components may be dissolved in at least one solvent prior to or after mixing. The use of the at least one co-solvent is particularly needed when the mixture of the sulfonamide of formula (I) and the lithium salts is solid, or comprises solid particles such as a suspension, or a precipitate.

[0079] It is preferable that the mixture obtained from step (iii) is stirred for a certain time to ensure that a homogeneous solution is obtained (i.e. no suspendedmatter is visible). The stirring is performedmagnetically at 100 rpm, at 200 rpm, at 300 rpm, at 400 rpm, at 500 rpm, at 600 rpm, at 700 rpm, at 800 rpm, at 900 rpm, at 1000 rpm; preferably, the stirring is performed ina rangebetween100and500 rpm,evenmorepreferablyat about 300 rpm.Additionally, themixture fromstep (iii) is stirred for at least 5 min, at least 15 min, at least 30 min, at least 1 hour, at least 2 hours, at least 4 hours, at least 6 hours, at least 12 hours, at least 1 day; preferably, themixture from step (iii) is stirred for 1 to 4 hours, more preferably for 2 hours.

[0080] All the steps of the method above are performed at a temperature comprised between 10 and 30 °C, preferably between 15 and 25 °C, even more preferably between 20 and 25 °C (room temperature). Methods for preparing the electrochemical cell or battery comprising said electrolyte

[0081] Themethod forpreparing theelectrochemical cell of the invention isapparent to theskilledpersonusingcommon general knowledge. A further aspect of the invention is directed at said method, which comprises the steps of: (i) providing a cathode for an electrochemical cell or a battery; (ii) providing an anode for an electrochemical cell or a battery; (iii) providing the liquid electrolyte as defined above or in any preferred or particular embodiment of the first aspect of the invention; and (iv) coating the surface of the cathode provided in step (i) and of the anode provided in step (ii) with the electrolyte provided in step (iii), being said surfaces optionally covered with a porous separator, prior to coating with the electrolyte, in a manner that the electrolyte is arranged between the cathode and the anode such that lithium cations can flow from the cathode to the anode.

[0082] In particular embodiment, theprovisionof the cathode in step (i) comprises thepreparationof a slurry ina solvent, for example N-methyl‑2-pyrrolidone, and casting on a suitable substrate, for example an aluminum current collector.

[0083] In a particular embodiment, the coating step (iv) is performedbycasting techniquesas known in theart. As stated above such surfacesmaybe coveredwith a porous separator. Preferably, suchporous separator is a polymeric separator, more preferably is a polypropylene separator.

[0084] Preferred materials for the preparation of the electrochemical cell or battery are as defined in the preferred and particular embodiments of the electrochemical cell described above. EXAMPLES

[0085] The following examples are intended to illustrate but not to limit the disclosed embodiments. List of abbreviations

[0086] FSA11: Dimethylsulfamoyl Fluoride Triglyme: Triethylene glycol dimethyl ether LiFSI: lithium bis(fluorosulfonyl)imide (LiN(SO2F)2 LiDFOB: Lithium difluoro(oxalato)borate (LiBF2(C2O4)) EC: ethylene carbonate FEC: fluoroethylene carbonate rpm: revolutions per minute 12 EP 4 730 463 A1 5 10 15 20 25 30 35 40 45 50 55 RT: room temperature Reagents and starting materials

[0087] The following chemicals were purchased from Sigma-Aldrich, Chemfish, TCI and were dried under vacuum (when required at 70 °C) and / or with molecular sieves before use. Example 1: Preparation of electrolytes

[0088] Five electrolytes having the compositions (expressed in weight %) disclosed in the table below were prepared according to the following general procedure. Electrolyte 1 (E1) (comparative)

[0089] LiFSIwasweighed in a vial andFSA11wasadded in anappropriate amount. The resultingmixturewas left under stirring for approximately 2 h at 300 rpm and room temperature. Electrolyte 2 (E2) (according to the invention)

[0090] In a first step, LiDFOBwasweighed in a vial and the corresponding amount of triglymewasadded and left stirring during 10 minutes at 300 rpm and room temperature. Next, LiFSI was weighed and FSA11 was added. The resulting mixture was left under stirring for approximately 2 h at 300 rpm and room temperature. Electrolyte 3 (E3) (comparative)

[0091] In a first step, LiDFOB was weighed in a vial and the corresponding amount of EC was added and left stirring during 10 minutes at 300 rpm and room temperature. Next, LiFSI was weighed and FSA11 was added. The resulting mixture was left under stirring for approximately 2 h at 300 rpm and room temperature. Electrolyte 4 (E4) (comparative)

[0092] In a first step, LiDFOB was weighed in a vial and the corresponding amount of FEC was added and left stirring during 10 minutes at 300 rpm and room temperature. Next, LiFSI was weighed and FSA11 was added. The resulting mixture was left under stirring for approximately 2 h at 300 rpm and room temperature.

[0093] The final electrolyte compositions were the following: Compound Electrolyte E1 (comparative) Electrolyte E2 (invention) Electrolyte E3 (comparative) Electrolyte 4 (comparative) FSA11 86.83 81.83 80.2 79.43 TRIGLYME -- 5.98 EC 7.85 FEC 8.74 LiFSI 13.17 11.72 11.48 11.37 LiDFOB -- 0.47 0.46 0.46 Example 2: Preparation of electrochemical cell

[0094] Lithium metal batteries comprising the electrolytes of Example 1 were prepared according to the following procedure: Cathode preparation: LiFePO4 cathode was composed of 96.5 wt.% of LFP (Y7 from Hunan Yuneng), 1.5 wt. % of conductive carbon (comprised of 1.0% Super P Carbon and 0.5% of Carbon Nanotubes), and 2 wt.% of polymeric binder (PVdF). A slurry was made using N-methyl‑2-pyrrolidone (NMP) as solvent and after homogenization of the dispersion it was cast ona 12µmthick aluminumcurrent collector. Finally, it was dried overnight at 80‑120 °Cunder vacuum, leading to an average loading of ca. 2.3 mAh cm‑2. 13 EP 4 730 463 A1 5 10 15 20 25 30 35 40 45 50 55

[0095] Anode provision: Li metal foil (China Energy Lithium, 14 mm diameter and 50 µm thickness).

[0096] Cell assembly: a coin cell was assembled in anArgon filled glovebox using theLFP (12mmdiameter) cathodeas definedabove,Celgard®H2010 (a20µmtrilayermicroporousmembranePP / PE / PP)asseparatorand theLimetal diskas anode. The liquid electrolytes prepared according to example 1 were injected between the cathode and the separator. Example 3: Electrochemical measurements

[0097] The cells prepared as described in example 2 were cycled galvanostatically, between 2.8 Vand 3.65 V vs. Li / Li+ using aMaccorBattery Tester (Series 4000). The applied protocolwas basedon 1 cycle at a current of C / 10, then constant cycling at either C / 2-D / 2 at 25 °C.

[0098] Figure 1 shows the capacity retention vs. cycle number for the Li°∥LFP cells at 25 °C, comprising an electrolyte containinga) amixtureof LiFSI lithiumsalt in FSA11at amolar concentrationof 1.0M (E1); b) LiFSI / LiDFOB lithiumsalts at a molar concentration of 0.95 M and 0.05 M, respectively in a FSA11 / Triglyme in 90 / 10 vol.% ratio of solvents (E2); c) LiFSI / LiDFOB lithium salts at amolar concentration of 0.95Mand 0.05M, respectively in a FSA11 / EC in 90 / 10 vol.% ratio of solvents (E3); and d) LiFSI / LiDFOB lithium salts at a molar concentration of 0.95 M and 0.05 M, respectively in a FSA11 / FEC in 90 / 10 vol.% ratio of solvents (E4).

[0099] In Figure 1, it is shown that the electrolyte (E2) according to the invention and having amixture of two lithium salts and a co-solvent exhibits better capacity retention, when compared to the capacity retention of an electrolyte having only one lithium salt and lacking a co-solvent (E1), used as a reference. After 75 cycles. E1 and E2 are reaching a specific capacity of 124 mAh g‑1 and 141 mAh g‑1, respectively.

[0100] It can also be seen that the incorporation of carbonates as co-solvents in comparative electrolytes E3 and E4 adversely affects cyclability, leading to noticeable capacity fading after 50 cycles when compared to electrolytes lacking carbonates.Withoutwishing to be bound to any theory, the addition of carbonates seems to have an impact on formedSEI on the anode side. The columbic efficiency of cycled cells with carbonates is lower at and of cycling compared to the one without carbonates, suggesting thatmore side reaction is appearing on the anode side. After around 55 cycles the internal resistivity of the cell rises to the value where further cycling is impossible. Claims 1. A liquid electrolyte comprising: i. at least one sulfonamide with general formula I wherein - R1 and R2 are each independently selected from a linear or branched C1‑C12 alkyl group which may be substituted with one or more fluorine atom(s), a linear or branched C2‑C12 alkenyl group which may be substitutedwith one ormore fluorine atom(s), aC6‑C12 aryl groupwhichmay be substitutedwith one ormore fluorine atom(s), 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 be combined with each other to form a nitrogen-containing aliphatic ring; ii. a combination of at least two lithium salts selected from the group consisting of LiClO4, LiNO3, LiBF4, LiAsF6, LiPF6, LiBF3Cl, LiF, LiN(SO2F)2, LiN(SO2CF2H)2, LiN(SO2CF3)2, LiN(SO2CF3)(SO2CF2H), LiN(SO2CF3) (SO2F), LiN(SO2CHF2)(SO2F), LiN(C2F5SO2)(SO2F), LiB(C2O4)2, LiBF2(C2O4), LiC(SO2CF3)3, LiPF3 (C2F5)3, and LiCF3SO3; and iii. at least, a. one co-solvent selected from the group consisting of 1,2-bis (2,2-difluoroethoxy) ethane (DF2EO), dimethoxy ethane (DME), 1,2-diethoxyethane (DEE), 1,3-dioxolane (DOL), diethylene glycol dimethyl ether 14 EP 4 730 463 A1 5 10 15 20 25 30 35 40 45 50 55 (DEGDME), triethylene glycol dimethyl ether (Triglyme), tetraethylene glycol dimethyl ether (TEGDME), poly(ethylene glycol) dimethyl ether (PEGDME), tetrahydropyran (THP), γ-butyrolactone, tetrahydrofuran (THF), 2-methyltetrahydrofuran, diethylether, methyl-tert-butylether, succinonitrile (SN), glutaronitrile (GN), adiponitrile (AN), N,N-dimethyltrifluoromethane-sulfonamide (TFSA), N,N-dimethyldifluoromethane-sulfo- namide (DFSA), ethylene sulfite (ES), propylene sulfite (PS), di-ethylene sulfite (DES), di-methylsulfite (DMS), triethyl phosphate (TEP), difluoroethyl acetate (DFEA), methyl difluoroacetate (MDFA), 2‑(2,2,2- trifluoroethoxy)ethyl methyl ether (TEME), 2-methoxyethoxy 2,2 difluroethylether (MDFE), triethyl phos- phate (TEP), trimethyl phosphate (TMP), tripropyl phosphate (TPP), methyl formate (MF), methyl acetate (MA), methyl butyrate (MB), ethyl acetate (EA), ethyl propionate (EP), trimethylsilylpropane sulfonate (TMSP), and acetamide of chemical structure R1CONR2R3 where R1 can be F, CF3, CF2H or CFH2, and R2 and R3 can be independently H, ‑(CH2)nCH3, ‑(CH2)nCF3, ‑(CH2)nF, or - (CH2)nCH2F or ‑(CH2)nCHF2 where n = 1‑10; and / or b. one filler selected from the group consisting of fluorobenzene (FPh), 1,2-difluoro benzene, 1,3-difluoro benzene, 1,4-difluorobenzene, anisole, fluoroanisole, tris(2,2,2-trifluoroethyl) orthoformate (TFEO), tetra- fluoro 1‑(2,2,2-trifluoroethoxy)ethane (D2), bis(2,2,2-trifluoroethyl)ether (BTFE), 1,1,2,2-tetrafluor- oethyl‑2,2,3,3-tetrafluoropropylether (TTE) and polyoxyethylene alkyl ethers; and wherein the liquid electrolyte does not comprise an organic carbonate. 2. The liquid electrolyte according to claim1,whereinR1andR2 in theat least one sulfonamidewith general formula I are each independently selected from a linear C1‑C6 alkyl group, a C2‑C6 alkenyl group, and ‑CH2CH2OCH2CH2O-CH3; or R1 and R2 may be combined with each other to form a 3‑ to 6-membered nitrogen-containing aliphatic ring. 3. The liquid electrolyte according to any one of claims 1 or 2, wherein the at least one sulfonamide represents from 5 to 95 wt.% of the weight of the liquid electrolyte, preferably from 30 to 90 wt.% of the weight of the electrolyte, more preferably from50 to 90wt.%of theweight of the electrolyte; evenmore preferably, from70 to 90wt.%of theweight of the electrolyte. 4. The liquid electrolyte according to any one of claims 1 to 3, wherein the combination of at least two lithium salts is selected fromLiN(SO2F)2, LiN(SO2CF3)(SO2CF2H), LiB(C2O4)2, LiBF2(C2O4), LiN(SO2CF3)2, LiN(SO2CF3)(SO2F), LiN(SO2F)(SO2CF2H), , preferably LiN(SO2F)2 and LiBF2(C2O4). 5. The liquid electrolyte according to any one of claims 1 to 4, wherein the amount of the at least two lithium salts ranges from5 to 45wt.%, preferably from5 to 25wt.%,more preferably from8 to 18wt.%, evenmore preferably from10 to 15 wt.%, with respect to the total weight of the electrolyte. 6. The liquid electrolyte according to any one of claims 1 to 5, wherein the at least one co-solvent is present and is selected from the group consisting of triglyme, ethylene sulfite, and mixtures thereof. 7. The liquid electrolyte according to any one of claims 1 to 6, wherein the electrolyte further comprises: - at least one scavenger selected from the group consisting of Lithium hexamethyldisilazide (LiHMDS); and / or - at least one flame retardant selected from the group consisting of Hexafluorocyclotriphosphazene (HFPN), Ethoxy (pentafluoro) cyclotriphosphazene (PFPN), ammonium polyphosphate, melamine polyphosphate, pen- taerythritol phosphate, piperazine pyrophosphate, aluminum diethyl hypophosphite, aluminum hypophosphite, aluminum phosphate, calcium borate, zinc borate, magnesium borate, aluminum borate, silicon dioxide, metakaolin, sepiolite, mica, zeolite, montmorillonite, glass powder and combinations thereof, preferably Hexa- fluorocyclotriphosphazene (HFPN),Ethoxy (pentafluoro) cyclotriphosphazene (PFPN), and combinations there- of. 8. The liquid electrolyte according to any one of claims 1 to 7, comprising: i. N,N-dimethylsulfamoyl fluoride; ii. a combination of the lithium salt LiFSI and LiBF2(C2O4); and iii. at least one co-solvent selected from the group consisting of triglyme, ethylene sulfite, and mixtures thereof; wherein the liquid electrolyte does not comprise an organic carbonate. 15 EP 4 730 463 A1 5 10 15 20 25 30 35 40 45 50 55 9. The liquid electrolyte according to anyoneof claims1 to6,wherein theat least one filler is present and is selected from the group consisting of fluorobenzene (FPh), 1,2-difluoro benzene, 1,3-difluoro benzene, 1,4-difluorobenzene, anisole, fluoroanisole, tris(2,2,2-trifluoroethyl) orthoformate (TFEO), tetrafluoro 1‑(2,2,2-trifluoroethoxy)ethane (D2), bis(2,2,2-trifluoroethyl)ether (BTFE), 1,1,2,2-tetrafluoroethyl‑2,2,3,3-tetrafluoropropylether (TTE) and polyox- yethylene alkyl ethers. 10. An electrochemical cell or battery comprising the liquid electrolyte according to any one of claims 1 to 9, a cathode, an anode, and, optionally, a separator. 11. Theelectrochemical cell or battery according to claim10,wherein the cathode is selected from the group consisting of lithium iron phosphate LiFePO4 (LFP) and a lithium manganese iron phosphate LiFexMn1-xPO4, wherein x < 1 (LMFP). 12. The electrochemical cell or battery according to any one of claims 10 or 11, comprising an anode selected from a lithium metal. 13. Use of the electrochemical cell or battery according to any one of claims 10 to 12, in electric motors; electric cars, including electric vehicles (EV), hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEV), or the like; electric carts, including electric bikes (E-bikes) and electric scooters (E-scooters); electric golf carts; or electric power storage systems. 14. A method for preparing the liquid electrolyte according to any one of claims 1 to 9, comprising the steps of (i) providing a combination of at least two lithium salts; (ii) mixing at least one sulfonamide of formula I with the salts of step (i); (iii) adding to the mixture at least, a. one co-solvent selected from the group consisting of 1,2-bis (2,2-difluoroethoxy) ethane (DF2EO), dimethoxy ethane (DME), 1,2-diethoxyethane (DEE), 1,3-dioxolane (DOL), diethylene glycol dimethyl ether (DEGDME), triethylene glycol dimethyl ether (Triglyme), tetraethylene glycol dimethyl ether (TEGDME), poly(ethylene glycol) dimethyl ether (PEGDME), tetrahydropyran (THP), γ-butyrolactone, tetrahydrofuran (THF), 2-methyltetrahydrofuran, diethylether, methyl-tert-butylether, succinonitrile (SN), glutaronitrile (GN), adiponitrile (AN), N,N-dimethyltrifluoromethane-sulfonamide (TFSA), N,N-dimethyldifluoromethane-sulfo- namide (DFSA), ethylene sulfite (ES), propylene sulfite (PS), di-ethylene sulfite (DES), di-methylsulfite (DMS), triethyl phosphate (TEP), difluoroethyl acetate (DFEA), methyl difluoroacetate (MDFA), 2‑(2,2,2- trifluoroethoxy)ethyl methyl ether (TEME), 2-methoxyethoxy 2,2 difluroethylether (MDFE), triethyl phos- phate (TEP), trimethyl phosphate (TMP), tripropyl phosphate (TPP), methyl formate (MF), methyl acetate (MA), methyl butyrate (MB), ethyl acetate (EA), ethyl propionate (EP), trimethylsilylpropane sulfonate (TMSP), and acetamide of chemical structure R1CONR2R3 where R1 can be F, CF3, CF2H or CFH2, and R2 and R3 can be independently H, ‑(CH2)nCH3, ‑(CH2)nCF3, ‑(CH2)nF, or ‑(CH2)nCH2F or - (CH2)nCHF2 where n = 1‑10; and / or b. one filler selected from the group consisting of fluorobenzene (FPh), 1,2-difluoro benzene, 1,3-difluoro benzene, 1,4-difluorobenzene, anisole, fluoroanisole, tris(2,2,2-trifluoroethyl) orthoformate (TFEO), tetra- fluoro 1‑(2,2,2,‑trifluoroethoxy)ethane (D2), bis(2,2,2-trifluoroethyl)ether (BTFE), 1,1,2,2,tetrafluor- oethyl‑2,2,3,3-tetrafluoropropylether (TTE) and polyoxyethylene alkyl ethers; and (iv) stirring the resulting mixture. 15. Amethod for preparing theelectrochemical cell or battery according to anyoneof claims10 to12comprising the steps of: (i) providing a cathode for an electrochemical cell or a battery; (ii) providing an anode for an electrochemical cell or a battery; (iii) providing the liquid electrolyte as defined in any one of claims 1 to 13; and (iv) coating the surface of the cathode provided in step (i) and of the anode provided in step (ii) with the electrolyte provided in step (iii), being said surfaces optionally covered with a porous separator, prior to coating with the electrolyte, in a manner that the electrolyte is arranged between the cathode and the anode such that lithium cations can flow from the cathode to the anode. 16 EP 4 730 463 A1 5 10 15 20 25 30 35 40 45 50 55 17 EP 4 730 463 A1 18 EP 4 730 463 A1 5 10 15 20 25 30 35 40 45 50 55 19 EP 4 730 463 A1 5 10 15 20 25 30 35 40 45 50 55 20 EP 4 730 463 A1 5 10 15 20 25 30 35 40 45 50 55 21 EP 4 730 463 A1 REFERENCES CITED IN THE DESCRIPTION This list of references cited by the applicant is for the reader’s convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard. Patent documents cited in the description • EP 3050872 A1

[0005] • US 9065146 B2

[0006] • WO 2022216593 A1

[0007] • US 8802301 B2

[0008] • WO 2022053881 A1

[0009] • US 2024322244 A

[0010] Non-patent literature cited in the description • XUE WEIJIANG et al. Energy & Environmental Science, 2020, vol. 13 (1), 212-220

[0011] 摘要 本发明涉及一种液体电解质，其包含：i .至少一种具有通式 I 的磺酰胺， ii. 至少两种锂盐的组合；以及 iii. 至少一种助溶剂和 / 或一种填料；并且其中所 述液体电解质不包含有机碳酸酯。本发明还涉及电化学电池及其用途，以及涉及 用于制备液体电解质和电化学电池的方法。

Claims

1. A liquid electrolyte comprising: i. at least one sulfonamide with general formula I wherein - R1 and R2 are each independently selected from a linear or branched C1-C12 alkyl group which may be substituted with one or more fluorine atom(s), a linear or branched C2-C12 alkenyl group which may be substituted with one or more fluorine atom(s), a C6-C12 aryl group which may be substituted with one or more fluorine atom(s), 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 be combined with each other to form a nitrogen-containing aliphatic ring; ii. a combination of at least two lithium salts selected from the group consisting of LiClO4, LiNO3, LiBF4, LiAsF6, LiPF6, LiBF3Cl, LiF, LiN(SO2F)2, LiN(SO2CF2H)2, LiN(SO2CF3)2, LiN(SO2CF3)(SO2CF2H), LiN(SO2CF3)(SO2F), LiN(SO2CHF2)(SO2F), LiN(C2F5SO2)(SO2F), LiB(C2O4)2, LiBF2(C2O4), LiC(SO2CF3)3, LiPF3(C2F5)3, and LiCF3SO3; and iii. at least, a. one co-solvent selected from the group consisting of 1,2-bis (2,2-difluoroethoxy) ethane (DF2EO), dimethoxy ethane (DME), 1,2-diethoxyethane (DEE), 1,3-dioxolane (DOL), diethylene glycol dimethyl ether (DEGDME), triethylene glycol dimethyl ether (Triglyme), tetraethylene glycol dimethyl ether (TEGDME), poly(ethylene glycol) dimethyl ether (PEGDME), tetrahydropyran (THP), γ-butyrolactone, tetrahydrofuran (THF), 2-methyltetrahydrofuran, diethylether, methyl-tert-butylether, succinonitrile (SN), glutaronitrile (GN), adiponitrile (AN), N,N-dimethyltrifluoromethane-sulfonamide (TFSA), N,N-dimethyldifluoromethane-sulfonamide (DFSA), ethylene sulfite (ES), propylene sulfite (PS), di-ethylene sulfite (DES), di-methylsulfite (DMS), triethyl phosphate (TEP), difluoroethyl acetate (DFEA), methyl difluoroacetate (MDFA), 2-(2,2,2-trifluoroethoxy)ethyl methyl ether (TEME), 2-methoxyethoxy 2,2 difluroethylether (MDFE), triethyl phosphate (TEP), trimethyl phosphate (TMP), tripropyl phosphate (TPP), methyl formate (MF), methyl acetate (MA), methyl butyrate (MB), ethyl acetate (EA), ethyl propionate (EP), trimethylsilylpropane sulfonate (TMSP), and acetamide of chemical structure R1CONR2R3 where R1 can be F, CF3, CF2H or CFH2, and R2 and R3 can be independently H, -(CH2)nCH3, -(CH2)nCF3, -(CH2)nF, or - (CH2)nCH2F or -(CH2)nCHF2 where n = 1-10; and / or b. one filler selected from the group consisting of fluorobenzene (FPh), 1,2-difluoro benzene, 1,3-difluoro benzene, 1,4-difluorobenzene, anisole, fluoroanisole, tris(2,2,2-trifluoroethyl) orthoformate (TFEO), tetrafluoro 1-(2,2,2-trifluoroethoxy)ethane (D2), bis(2,2,2-trifluoroethyl)ether (BTFE), 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropylether (TTE) and polyoxyethylene alkyl ethers; and wherein the liquid electrolyte does not comprise an organic carbonate.

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

3. The liquid electrolyte according to any one of claims 1 or 2, wherein the at least one sulfonamide represents from 5 to 95 wt.% of the weight of the liquid electrolyte, preferably from 30 to 90 wt.% of the weight of the electrolyte, more preferably from 50 to 90 wt.% of the weight of the electrolyte; even more preferably, from 70 to 90 wt.% of the weight of the electrolyte.

4. The liquid electrolyte according to any one of claims 1 to 3, wherein the combination of at least two lithium salts is selected from LiN(SO2F)2, LiN(SO2CF3)(SO2CF2H), LiB(C2O4)2, LiBF2(C2O4), LiN(SO2CF3)2, LiN(SO2CF3)(SO2F), LiN(SO2F)(SO2CF2H), , preferably LiN(SO2F)2 and LiBF2(C2O4).

5. The liquid electrolyte according to any one of claims 1 to 4, wherein the amount of the at least two lithium salts ranges from 5 to 45 wt.%, preferably from 5 to 25 wt.%, more preferably from 8 to 18 wt.%, even more preferably from 10 to 15 wt.%, with respect to the total weight of the electrolyte.

6. The liquid electrolyte according to any one of claims 1 to 5, wherein the at least one co-solvent is present and is selected from the group consisting of triglyme, ethylene sulfite, and mixtures thereof.

7. The liquid electrolyte according to any one of claims 1 to 6, wherein the electrolyte further comprises: - at least one scavenger selected from the group consisting of Lithium hexamethyldisilazide (LiHMDS); and / or - at least one flame retardant selected from the group consisting of Hexafluorocyclotriphosphazene (HFPN), Ethoxy (pentafluoro) cyclotriphosphazene (PFPN), ammonium polyphosphate, melamine polyphosphate, pentaerythritol phosphate, piperazine pyrophosphate, aluminum diethyl hypophosphite, aluminum hypophosphite, aluminum phosphate, calcium borate, zinc borate, magnesium borate, aluminum borate, silicon dioxide, metakaolin, sepiolite, mica, zeolite, montmorillonite, glass powder and combinations thereof, preferably Hexafluorocyclotriphosphazene (HFPN), Ethoxy (pentafluoro) cyclotriphosphazene (PFPN), and combinations thereof.

8. The liquid electrolyte according to any one of claims 1 to 7, comprising: i. N,N-dimethylsulfamoyl fluoride; ii. a combination of the lithium salt LiFSI and LiBF2(C2O4); and iii. at least one co-solvent selected from the group consisting of triglyme, ethylene sulfite, and mixtures thereof; wherein the liquid electrolyte does not comprise an organic carbonate.

9. The liquid electrolyte according to any one of claims 1 to 6, wherein the at least one filler is present and is selected from the group consisting of fluorobenzene (FPh), 1,2-difluoro benzene, 1,3-difluoro benzene, 1,4-difluorobenzene, anisole, fluoroanisole, tris(2,2,2-trifluoroethyl) orthoformate (TFEO), tetrafluoro 1-(2,2,2-trifluoroethoxy)ethane (D2), bis(2,2,2-trifluoroethyl)ether (BTFE), 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropylether (TTE) and polyoxyethylene alkyl ethers.

10. An electrochemical cell or battery comprising the liquid electrolyte according to any one of claims 1 to 9, a cathode, an anode, and, optionally, a separator.

11. The electrochemical cell or battery according to claim 10, wherein the cathode is selected from the group consisting of lithium iron phosphate LiFePO4 (LFP) and a lithium manganese iron phosphate LiFexMn1-xPO4, wherein x < 1 (LMFP).

12. The electrochemical cell or battery according to any one of claims 10 or 11, comprising an anode selected from a lithium metal.

13. Use of the electrochemical cell or battery according to any one of claims 10 to 12, in electric motors; electric cars, including electric vehicles (EV), hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEV), or the like; electric carts, including electric bikes (E-bikes) and electric scooters (E-scooters); electric golf carts; or electric power storage systems.

14. A method for preparing the liquid electrolyte according to any one of claims 1 to 9, comprising the steps of (i) providing a combination of at least two lithium salts; (ii) mixing at least one sulfonamide of formula I with the salts of step (i); (iii) adding to the mixture at least, a. one co-solvent selected from the group consisting of 1,2-bis (2,2-difluoroethoxy) ethane (DF2EO), dimethoxy ethane (DME), 1,2-diethoxyethane (DEE), 1,3-dioxolane (DOL), diethylene glycol dimethyl ether (DEGDME), triethylene glycol dimethyl ether (Triglyme), tetraethylene glycol dimethyl ether (TEGDME), poly(ethylene glycol) dimethyl ether (PEGDME), tetrahydropyran (THP), γ-butyrolactone, tetrahydrofuran (THF), 2-methyltetrahydrofuran, diethylether, methyl-tert-butylether, succinonitrile (SN), glutaronitrile (GN), adiponitrile (AN), N,N-dimethyltrifluoromethane-sulfonamide (TFSA), N,N-dimethyldifluoromethane-sulfonamide (DFSA), ethylene sulfite (ES), propylene sulfite (PS), di-ethylene sulfite (DES), di-methylsulfite (DMS), triethyl phosphate (TEP), difluoroethyl acetate (DFEA), methyl difluoroacetate (MDFA), 2-(2,2,2-trifluoroethoxy)ethyl methyl ether (TEME), 2-methoxyethoxy 2,2 difluroethylether (MDFE), triethyl phosphate (TEP), trimethyl phosphate (TMP), tripropyl phosphate (TPP), methyl formate (MF), methyl acetate (MA), methyl butyrate (MB), ethyl acetate (EA), ethyl propionate (EP), trimethylsilylpropane sulfonate (TMSP), and acetamide of chemical structure R1CONR2R3 where R1 can be F, CF3, CF2H or CFH2, and R2 and R3 can be independently H, -(CH2)nCH3, -(CH2)nCF3, -(CH2)nF, or -(CH2)nCH2F or - (CH2)nCHF2 where n = 1-10; and / or b. one filler selected from the group consisting of fluorobenzene (FPh), 1,2-difluoro benzene, 1,3-difluoro benzene, 1,4-difluorobenzene, anisole, fluoroanisole, tris(2,2,2-trifluoroethyl) orthoformate (TFEO), tetrafluoro 1-(2,2,2,-trifluoroethoxy)ethane (D2), bis(2,2,2-trifluoroethyl)ether (BTFE), 1,1,2,2,tetrafluoroethyl-2,2,3,3-tetrafluoropropylether (TTE) and polyoxyethylene alkyl ethers; and (iv) stirring the resulting mixture.

15. A method for preparing the electrochemical cell or battery according to any one of claims 10 to 12 comprising the steps of: (i) providing a cathode for an electrochemical cell or a battery; (ii) providing an anode for an electrochemical cell or a battery; (iii) providing the liquid electrolyte as defined in any one of claims 1 to 13; and (iv) coating the surface of the cathode provided in step (i) and of the anode provided in step (ii) with the electrolyte provided in step (iii), being said surfaces optionally covered with a porous separator, prior to coating with the electrolyte, in a manner that the electrolyte is arranged between the cathode and the anode such that lithium cations can flow from the cathode to the anode.

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