Solid electrolytes comprising an ionic bifunctional molecule, and use thereof in electrochemistry

Abstract

The present technology relates to a solid electrolyte comprising inorganic particles and an ionic bifunctional molecule for use in electrochemical applications. Also described are electrochemical cells and batteries comprising said solid electrolyte.

Description

[0001] SOLID ELECTROLYTES COMPRISING AN IONIC BIFUNCTIONAL MOLECULE, AND THEIR USE IN ELECTROCHEMISTRY

[0002] RELATED REQUEST

[0003] This application claims priority under applicable law from Canadian Provisional Patent Application No. 3,145,591 filed on January 14, 2022, the contents of which are incorporated herein by reference in their entirety and for all purposes.

[0004] TECHNICAL FIELD

[0005] The present application relates to the field of hybrid solid electrolytes comprising a ceramic and to their uses in electrochemical applications. More particularly, the present application relates to ionic compounds, to their manufacturing processes and to their uses in electrochemical cells, in particular in so-called all-solid-state batteries.

[0006] STATE OF THE ART

[0007] Liquid electrolytes used in lithium-ion batteries are flammable and slowly degrade to form a passivation layer on the surface of the lithium film or solid electrolyte interface (SEI), irreversibly consuming lithium, which decreases the battery's Coulombic efficiency. In addition, lithium anodes undergo significant morphological changes during battery cycling, and lithium dendrites are formed. Since these typically migrate through the electrolyte, they can eventually cause short circuits.

[0008] Safety concerns and the requirement for higher energy density have stimulated research into the development of an all-solid-state rechargeable lithium battery with a polymer, ceramic, or polymer-ceramic hybrid electrolyte, all three of which are more stable toward metallic lithium and reduce lithium dendrite growth.

[0009] However, the scope of application of solid electrolytes is still limited. Indeed, solid electrolytes have problems related to their limited electrochemical stability, limited interfacial stability, relatively low ionic conductivity, loss of reactivity, poor contact between solid interfaces, etc.

[0010] Therefore, there is a need for the development of all-solid-state electrochemical systems that exclude one or more of the disadvantages of conventional all-solid-state electrochemical systems.

[0011] SUMMARY

[0012] According to a first aspect, the present technology relates to a solid electrolyte comprising inorganic particles and an ionic bifunctional molecule of Formulas I or II:

[0013] Formula II in which,

[0014] A' is a delocalized anion;

[0015] R + is chosen from the groups -N + (RIR2R3) and -P + (RIR2R3);

[0016] Ri , R2, and R3 are independently selected from a linear or branched, substituted or unsubstituted C1-12alkyl group; or Ri and R2 together with the nitrogen or phosphorus atom form a single or multi-ring heterocycle having from 3 to 12 members and R3 is as previously defined; or Ri, R2, and R3 together with the nitrogen or phosphorus atom form a single or multi-ring heteroaromatic or partially unsaturated heterocycle having from 5 to 12 members;

[0017] L is a linear or branched C2-4 alkylene;

[0018] X is O or S; m is a number in the range 1 to 6; and n is a number in the range 1 to 11.

[0019] More particularly, the present technology relates to a solid electrolyte comprising inorganic particles and an ionic bifunctional molecule of Formulas I or II:

[0020] Formula II in which,

[0021] A- is a delocalized anion;

[0022] R + is chosen from the groups -N + (RIR2R3) and -PXR1R2R3) excluding cations derived from the superbases amidines, guanidines and phosphazenes;

[0023] Ri , R2, and R3 are independently selected from a linear or branched, substituted or unsubstituted C1-12alkyl group; or Ri and R2 together with the nitrogen or phosphorus atom form a single or multi-ring heterocycle having from 3 to 12 members and R3 is as previously defined; or Ri, R2, and R3 together with the nitrogen or phosphorus atom form a single or multi-ring heteroaromatic or partially unsaturated heterocycle having from 5 to 12 members;

[0024] L is a linear or branched C2-4alkylene;

[0025] X is O or S; m is a number in the range 1 to 6; and n is a number in the range 1 to 11.

[0026] According to one embodiment, the delocalized anion is selected from hexafluorophosphate (PF6-), bis(trifluoromethanesulfonyl)imide (TFSI-), bis(fluorosulfonyl)imide (TDI-), (flurosulfonyl)(trifluoromethanesulfonyl)imide (TFSI-), 2-trifluoromethyl-4,5-dicyanoimidazolate (TDI-), 4,5-dicyano-1,2,3-triazolate (DCTA-), bis(pentafluoroethylsulfonyl)imide (BEIT), difluorophosphate (DFP'), tetrafluoroborate (BF4'), bis(oxalato)borate (BOB'), nitrate (NOs'), perchlorate (CIO4'), hexafluoroarsenate (AsFe'), trifluoromethanesulfonate (CF3SO3- or -OTf), fluoroalkylphosphate ([PF3(CF2CF3)3]' or FAP'), tetrakis(trifluoroacetoxy)borate ([B(OCOCF3)4]' or TFAB'), bis(1,2-benzenediolato(2-)-O,O')borate ([B(C6O2)2]' or BBB'), difluoro(oxalato)borate (BF2(C2O4)- or FOB'), and an anion of formula BF2O4R X (R x = C2-4alkyl).

[0027] According to one example, the delocalized anion is selected from hexafluorophosphate (PF6-), bis(trifluoromethanesulfonyl)imide (TFSI'), bis(fluorosulfonyl)imide (FSI ), (flurosulfonyl)(trifluoromethanesulfonyl)imide (FTFSI'), tetrafluoroborate (BF4-), and trifluoromethanesulfonate (CF3SO3- or -OT.f)

[0028] In an example of interest, the delocalized anion is bis(trifluoromethanesulfonyl)imide (TFSI').

[0029] According to some embodiments, R + is a -N grouping + (RI R2R3).

[0030] According to one example, R1, R2, and R3 are independently selected from linear or branched, substituted or unsubstituted C1-12alkyl groups.

[0031] According to another example, R1, R2, and R3 are independently selected from linear or branched C1-12alkyl groups, or at least one of R1, R2, or R3 is substituted by a halogen atom or an alkoxyl, ether, ester, or siloxy group.

[0032] According to another example, R1 and R2 together with the nitrogen atom form a heterocycle with one or more rings and having from 3 to 12 members and R3 is as previously defined, preferably R3 is a C1-12alkyl, or a C1-4alkyl.

[0033] In another example, R1, R2, and R3 together with the nitrogen atom form a single or multi-ring partially unsaturated heteroaromatic or heterocycle having 5 to 12 members.

[0034] According to another example, R + is chosen from: in which R3 is as previously defined, R4 is a linear or branched, substituted or unsubstituted C1-12alkyl, C1-12alkenyl or C1-12alkynyl group, R5 is a hydrogen atom, or a linear or branched, substituted or unsubstituted C1-12alkyl, C1-12alkenyl or C1-12alkynyl group, and the heterocycle is optionally substituted.

[0035] According to one example, R4 is a C1-4alkyl group.

[0036] According to another example, R5 is a C1-4alkyl group.

[0037] According to another example, R3 is an unsubstituted C1-4alkyl group. According to an example of interest, R3 is selected from a methyl group, an ethyl group, an n- or i-propyl group, and an n-, i-, s- or t-butyl group.

[0038] According to certain other embodiments, R + is a -P grouping + (RIR2R3).

[0039] According to one example, R1, R2, and R3 are independently selected from linear or branched, substituted or unsubstituted C1-12alkyl groups.

[0040] In another example, R1, R2, and R3 are independently selected from linear or branched C1-12alkyl groups, or at least one of R1, R2, or R3 is substituted with a halogen atom or an alkoxyl, ether, ester, or siloxy group.

[0041] According to another embodiment, n is a number in the range 2 to 10, or 3 to 8, or 4 to 6.

[0042] According to another embodiment, the ionic bifunctional molecule is 1,1'-(1,6-hexamethylene) bis(1-methylpyrrolidinium) bis(trifluoromethanesulfonyl)imide.

[0043] According to another embodiment, the ionic bifunctional molecule is 1,1'-(1,12-dodecamethylene) bis(1-methylpyrrolidinium) bis(trifluoromethanesulfonyl)imide. According to another embodiment, the ionic bifunctional molecule is 1,1'-(2,2'-(ethylenedioxy)diethane) bis(1-methylpyrrolidinium) bis(trifluoromethanesulfonyl)imide.

[0044] According to another embodiment, the ionic bifunctional molecule is 1,1'-(thiol bis(1,2-ethane)) bis(1-methylpyrrolidinum) bis(trifluoromethanesulfonyl)imide.

[0045] According to another embodiment, the ionic bifunctional molecule is 3,3'-(1,6-hexamethylene) bis(1,2-dimethylimidazolium) bis(trifluoromethanesulfonyl)imide.

[0046] In another embodiment, the ionic bifunctional molecule is at a concentration of about 0.5% to about 50%, or about 2% to about 30%, or about 4% to about 20%, or about 5% to about 15%, by weight in the solid electrolyte.

[0047] According to another embodiment, the inorganic particles comprise a material selected from glasses, glass-ceramics, ceramics, nanoceramics and a combination of at least two of these.

[0048] In some preferred embodiments, the inorganic particles comprise a fluoride, phosphide, sulfide, oxysulfide, or oxide-based ceramic, glass, or glass-ceramic.

[0049] According to certain other preferred embodiments, the inorganic particles comprise a LISICON, thio-LISICON, argyrodite, garnet, NASICON, perovskite, oxide, sulfide, oxysulfide, phosphide, fluoride compound in crystalline and / or amorphous form, or a combination of at least two thereof.

[0050] According to certain other preferred embodiments, the inorganic particles comprise a compound selected from inorganic compounds of formulas MLZO

[0051] in which,

[0052] M is an alkali metal ion, an alkaline earth metal ion, or a combination of two or more thereof, and wherein when M comprises an alkaline earth metal ion, then the number of M is adjusted to achieve electroneutrality;

[0053] X is selected from F, Cl, Br, I or a combination of at least two thereof; a, b, c, d, e and f are non-zero numbers and are, independently in each formula, selected to achieve electroneutrality; and v, w, x, y and z are non-zero numbers and are, independently in each formula, selected to obtain a stable compound.

[0054] According to one example, M is selected from Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, Ba or a combination of at least two of these. For example, M is Li.

[0055] In another example, the inorganic particles comprise an inorganic compound of the formula MATP.

[0056] In another example, the inorganic particles comprise an argyrodite-type inorganic compound of the formula Li6PS5X, wherein X is Cl, Br, I, or a combination of at least two thereof.

[0057] In another example, the inorganic particles comprise an inorganic compound of the formula Li6PS5CI. In another embodiment, the inorganic particles are present at a concentration of about 25% to about 95%, or about 40% to about 90%, or about 60% to about 90%, by weight in the solid electrolyte.

[0058] According to another embodiment, the ratio of "inorganic particles: ionic bifunctional molecule" by weight is in the range of 2:1 to 30:1, or 3:1 to 20:1, or 5:1 to 15:1.

[0059] According to another embodiment, the solid electrolyte further comprises a polymer.

[0060] According to one example, the polymer is a linear or branched polymer selected from polyethers, polythioethers, polyesters, polythioesters, poly(dimethylsiloxanes), poly(alkylene carbonate), poly(alkylene thiocarbonate), poly(alkylene sulfones), poly(alkylene sulfamides), polyimides, polyamides, polyphosphazenes, polyurethanes, poly(vinyl alcohol), polyacrylonitriles, polyethacrylates and polymethacrylates, and their copolymers.

[0061] For example, the polyether is poly(ethylene oxide) (PEO), poly(propylene oxide) (POP), or a copolymer (EO / PO).

[0062] According to another example, the crosslinkable functional group is chosen from acrylate, methacrylate, vinyl, glycidyl and mercapto functional groups.

[0063] According to another example, the polymer is the reaction product of at least one monomer comprising at least one polymerizable or crosslinkable function and a compound comprising at least one SH functional group.

[0064] In another embodiment, the polymer is present at a concentration of about 0.1% to about 20%, or about 1% to about 15%, or about 2% to about 10%, by weight in the solid electrolyte.

[0065] According to another embodiment, the solid electrolyte further comprises an additive.

[0066] In one example, the additive is a fluorinated compound comprising an amide function. For example, the fluorinated compound has the formula R 6 X 6 C(O)N(H)X 7 R 7 , where R 6 and R 7 are independently alkyl, cycloalkyl, heterocycloalkyl, aryl, or heteroaryl groups, X 6 is O, NH or absent, and X 7is absent or is a C(O), S(O)2, or Si(R) group 8 R 9 ), where R 8 and R 9 alkyl groups, and where at least one of R 6 , R 7 , R 8 and R 9 is a group substituted by one or more fluorine atom(s). According to an example of interest, R 6 is a perfluorinated group and X 6 is absent.

[0067] In another example, the additive is present at a concentration of about 5% to about 40%, or about 10% to about 35%, or about 15% to about 30%, by weight in the solid electrolyte.

[0068] In another aspect, the present technology relates to an electrochemical cell comprising a negative electrode, a positive electrode and an electrolyte, wherein the electrolyte is as defined herein.

[0069] According to one embodiment, the positive electrode comprises a positive electrode material comprising an electrochemically active positive electrode material.

[0070] In one example, the positive electrode material is on a current collector.

[0071] According to another example, the electrochemically active positive electrode material is selected from metal phosphates, lithium metal phosphates, metal oxides, and lithium metal oxides.

[0072] In another example, the positive electrode electrochemically active material is LiM'PO4 where M' is Fe, Ni, Mn, Co, or a combination of at least two thereof, LiV3Os, V2O5F, LiV2O5, LiMn2C>4, LiM”C>2, where M” is Mn, Co, Ni, or a combination of at least two thereof (such as NMC, LiMn x Co y Neither zO2 with x+y+z = 1), Li(NiM'”)O2 (where M'” is Mn, Co, Al, Fe, Cr, Ti, Zr, or a combination of two or more of these), elemental sulfur, selenium or iodine, iron(lll) fluoride, copper(lll) fluoride, lithium iodide, carbon-based active materials such as graphite, organic cathode active materials, or a combination of two or more of these, when compatible with each other.

[0073] In another embodiment, the positive electrode material further comprises an electronically conductive material, a binder, a salt, an ionic bifunctional molecule, and / or inorganic particles. In another embodiment, the negative electrode comprises a negative electrode material comprising an electrochemically active negative electrode material.

[0074] In one example, the negative electrode material is on a current collector.

[0075] According to certain preferred embodiments, the negative electrode electrochemically active material comprises a metal film comprising an alkali or alkaline earth metal or an alloy comprising an alkali or alkaline earth metal. In one example, the alkali metal is selected from lithium and sodium.

[0076] In some other preferred embodiments, the negative electrode electrochemically active material comprises an intermetallic compound (e.g., SnSb, TiSnSb, Cu2Sb, AlSb, FeSb2, FeSn2, and CoSn2), a metal oxide, a metal nitride, a metal phosphide, a metal phosphate (e.g., LiTi2(PC>4)3), a metal halide (e.g., a metal fluoride), a metal sulfide, a metal oxysulfide, a carbon (e.g., graphite, graphene, reduced graphene oxide, hard carbon, soft carbon, exfoliated graphite, and amorphous carbon), silicon (Si), a silicon-carbon composite (Si-C), a silicon oxide (SiO x ), a silicon oxide-carbon composite (SiO x -C), tin (Sn), a tin-carbon composite (Sn-C), a tin oxide (SnO x ), a tin oxide-carbon composite (SnO x-C), and combinations thereof, when compatible. According to one example, the metal oxide is chosen from compounds of formulas M””bO c (where M”” is Ti, Mo, Mn, Ni, Co, Cu, V, Fe, Zn, Nb, or a combination thereof; and b and c are numbers such that the ratio c:b is in the range 2 to 3) (for example, a lithium titanate (such as Li4Ti5O12) or a lithium molybdenum oxide (such as Li2MO4O13)). In an example of interest, the negative electrode material further comprises an electronically conductive material, a binder, a salt, an ionic bifunctional molecule, and / or inorganic particles.

[0077] According to another aspect, the present technology relates to a battery comprising at least one electrochemical cell as defined herein. According to one embodiment, said battery is selected from the group consisting of a lithium battery, a lithium-ion battery, a sodium battery, a sodium-ion battery, a potassium battery, a potassium-ion battery, a magnesium battery, and a magnesium-ion battery. According to an example of interest, said battery is a lithium battery. According to another example of interest, said battery is a lithium-ion battery.

[0078] BRIEF DESCRIPTION OF THE FIGURES

[0079] Figure 1 presents the results of the differential scanning calorimetry analysis obtained for Salts 1, 2, 4 and 5, as described in Example 3.

[0080] Figure 2 shows the results of the thermogravimetric analysis obtained for Salts 1 to 5, as described in Example 3.

[0081] Figure 3 is a graph showing the linear sweep voltammetry curves obtained for cells comprising electrolytes E1 to E3, as described in Example 4(b).

[0082] Figure 4 is a graph showing the cyclic voltammetry curves obtained for cells comprising electrolytes E2 and E3, as described in Example 4(b).

[0083] Figure 5 shows images of a lithium foil dipped respectively in (A) into tetraethylene glycol dimethyl ether (TEGDME), in (B) into a solution of 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide ([PYR1,4]TFSI) in TEGDME, and in (C) into a solution of Salt 1 in TEGDME, as described in Example 4(c).

[0084] Figure 6 shows images of a solid electrolyte pellet, as described in Example 5(a).

[0085] Figure 7 is a graph showing the ionic conductivity results versus temperature for the Cells as described in Example 6(b). Figure 8 is a graph showing the ionic conductivity results as a function of temperature for the Cells as described in Example 6(b).

[0086] Figure 9 shows images of the ceramic-ionic plastic salt composite solid electrolyte film E6 obtained by scanning electron microscopy (SEM) in (A) before creep, and in (B) and (C) after creep at a temperature of 70°C, as described in Example 6(c).

[0087] Figure 10 is a graph showing the ionic conductivity results as a function of temperature for the Cells as described in Example 7(b).

[0088] DETAILED DESCRIPTION

[0089] All technical and scientific terms and expressions used herein have the same definitions as those generally understood by those skilled in the art of the present technology. Definitions of certain terms and expressions used are nevertheless provided below.

[0090] When the term "about" is used here, it means approximately, in the region of, or around. For example, when the term "about" is used in connection with a numerical value, it modifies it above and below by a variation of 10% from its nominal value. This term may also take into account, for example, the experimental error of a measuring device or rounding.

[0091] Where a range of values ​​is referred to in this application, the lower and upper bounds of the range are, unless otherwise indicated, always included in the definition. Where a range of values ​​is referred to in this application, then all intermediate ranges and sub-ranges, as well as individual values ​​included in ranges of values, are included in the definition.

[0092] When the article "a" is used to introduce an element in the present application, it does not have the meaning of "a single one", but rather of "one or more". Of course, where the description states that a particular step, component, element or feature "may" or "could" be included, that particular step, component, element or feature is not required to be included in every embodiment.

[0093] The chemical structures described here are drawn according to the conventions of the field. Also, when an atom, such as a carbon atom, as drawn appears to include an incomplete valence, then the valence is assumed to be satisfied by one or more hydrogen atoms even if they are not explicitly drawn.

[0094] As used herein, the term "alkyl" refers to saturated hydrocarbons having from 1 to 12 carbon atoms, including straight or branched alkyl groups. Non-limiting examples of alkyl groups may include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, isopropyl, tert-butyl, sec-butyl, isobutyl, and so on. When the alkyl group is located between two functional groups, then the term alkyl also includes alkylene groups such as methylene, ethylene, propylene, and so on. The terms "C m -Cn alkyl" and "C m -C n alkylene" refer respectively to an alkyl or alkylene group having from the indicated number "m" to the indicated number "n" of carbon atoms.

[0095] As used herein, the term "cycloalkyl" as used herein means a group comprising one or more saturated or partially unsaturated (non-aromatic) carbocyclic rings comprising from 3 to 15 members in a monocyclic or polycyclic ring system, including spiro (sharing one atom), fused (sharing at least one bond), or bridged carbocycles and may be optionally substituted. Examples of cycloalkyl groups include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclopenten-1-yl, cyclopenten-2-yl, cyclopenten-3-yl, cyclohexyl, cyclohexen-1-yl, cyclohexen-2-yl, cyclohexen-3-yl, cycloheptyl and so on. When the cycloalkyl group is located between two functional groups, the term cycloalkylene may also be used.

[0096] As used herein, the term "heterocycloalkyl" refers to a group comprising a saturated or partially unsaturated (non-aromatic) carbocyclic ring comprising from 3 to 15 members in a monocyclic or polycyclic ring system, including spiro (sharing one atom), fused (sharing at least one bond), or bridged carbocycles and may be optionally substituted, and having carbon atoms and from 1 to 4 heteroatoms (e.g., N, O, S, or P) or groups containing such heteroatoms (e.g., NH, NR X (R xis an alkyl, acyl, aryl, heteroaryl, or cycloalkyl group), PO2, SO, SO2, and other similar groups). Heterocycloalkyl groups may be attached to a carbon atom or a heteroatom (e.g., via a nitrogen atom) where possible. The term heterocycloalkyl includes both unsubstituted and substituted heterocycloalkyl groups. When the heterocycloalkyl group is located between two functional groups, the term heterocycloalkylene may also be used.

[0097] The terms "aryl" or "aromatic" refer to an aromatic moiety having 4n+2 conjugated Tr(pi) electrons in which n is a number from 1 to 3, in a monocyclic group, or a fused bicyclic or tricyclic system having a total of 6 to 15 ring members, in which at least one of the rings in a system is aromatic. The terms "aryl" or "aromatic" refer to both monocyclic and conjugated polycyclic systems. The terms "aryl" or "aromatic" also include substituted or unsubstituted groups. Examples of aryl groups include, but are not limited to, phenyl, benzyl, phenethyl, 1-phenylethyl, tolyl, naphthyl, biphenyl, terphenyl, indenyl, benzocyclooctenyl, benzocycloheptenyl, azulenyl, acenaphthylenyl, fluorenyl, phenanthrenyl, anthracenyl, perylenyl, and so on.

[0098] The terms "heteroaryl", "heteroarylene", or "heteroaromatic" denote an aromatic group having 4n+2 conjugated Tr(pi) electrons in which n is a number from 1 to 3, for example having from 5 to 18 ring atoms, preferably 5, 6, or 9 ring atoms in a conjugated monocyclic or polycyclic system (fused or not); and having, in addition to carbon atoms, from 1 to 6 heteroatoms selected from oxygen, nitrogen and sulfur or groups containing such heteroatoms or groups containing such heteroatoms (for example, NH and NR X (R xis an alkyl, acyl, aryl, heteroaryl, or cycloalkyl group), SO, and other similar groups). A polycyclic ring system includes at least one heteroaromatic ring. Heteroaryls may be directly attached, or linked by a C1-C3alkyl group (also called heteroarylalkyl or heteroaralkyl). Heteroaryl groups may be linked to a carbon atom or a heteroatom (e.g., via a nitrogen atom), where possible. Generally, the term "substituted" means that one or more hydrogen atoms on the designated group are replaced by a suitable substituent. The substituents or combinations of substituents contemplated in this specification are those resulting in the formation of a chemically stable compound.Examples of substituents include halogen atoms (such as fluorine) and hydroxyl, oxo, alkyl, alkoxyl, alkoxyalkyl, nitrile, azido, carboxylate, alkoxycarbonyl, alkylcarbonyl, primary, secondary or tertiary amine, amide, nitro, silane, siloxane, thiocarboxylate, sulfonyl, sulfonate, alkenyl, alkynyl, aryl, heteroaryl, cycloalkyl, heterocycloalkyl, or a combination thereof.

[0099] The present technology generally relates to a solid electrolyte and its use in electrochemical applications. For example, the solid electrolyte may be a primarily inorganic solid electrolyte or a polymer-ceramic hybrid solid electrolyte.

[0100] The present technology relates more particularly to a solid electrolyte comprising inorganic particles and an ionic bifunctional molecule of Formulas I or II:

[0101] Formula II in which,

[0102] A- is a delocalized anion;

[0103] R + is chosen from the groups -N + (R1R2R3) and -P + (R1R2R3) excluding cations derived from the superbases amidines, guanidines and phosphazenes;

[0104] R1, R2, and R3 are independently selected from a linear or branched, substituted or unsubstituted C1-12alkyl group; or R1 and R2 together with the nitrogen or phosphorus atom form a single or multi-ring heterocycle having from 3 to 12 members and R3 is as previously defined; or R1, R2, and R3 together with the nitrogen or phosphorus atom form a single or multi-ring heteroaromatic or partially unsaturated heterocycle having from 5 to 12 members;

[0105] L is a linear or branched C2-4alkylene;

[0106] X is O or S; m is a number in the range 1 to 6; and n is a number in the range 1 to 11.

[0107] The delocalized anion may be selected from the group consisting of hexafluorophosphate (PF6-), bis(trifluoromethanesulfonyl)imide (TFSF), bis(fluorosulfonyl)imide (FSI-), (flurosulfonyl)(trifluoromethanesulfonyl)imide (TFSI-), 2-trifluoromethyl-4,5-dicyanoimidazolate (TDI-), 4,5-dicyano-1,2,3-triazolate (DCTA'), bis(pentafluoroethylsulfonyl)imide (BETI-), difluorophosphate (DFP'), tetrafluoroborate (BF4'), bis(oxalato)borate (BOB'), nitrate (NO3'), perchlorate (CIO4-), hexafluoroarsenate (AsF6-), trifluoromethanesulfonate (CF3SO3- or -OT,f) fluoroalkylphosphate ([PF3(CF2CF3)3]' or FAP'), tetrakis(trifluoroacetoxy)borate ([B(OCOCF3)4]' or TFAB'), bis(1,2-benzenediolato(2-)-O,O')borate ([B(CeO2)2]' or BBB'), difluoro(oxalato)borate (BF2(C2O4)' or FOB'), and an anion of formula BF2O4R X (R x= C2-4alkyl). For example, the delocalized anion is selected from the group consisting of hexafluorophosphate (PF6-), bis(trifluoromethanesulfonyl)imide (TFSI'), bis(fluorosulfonyl)imide (FSI ), (flurosulfonyl)(trifluoromethanesulfonyl)imide (FTFSI'), tetrafluoroborate (BF4'), and trifluoromethanesulfonate (CF3SO3- or -OT.f)

[0108] According to an example, R + is a group of formula -NXR1R2R3), in which R1, R2, and R3 are independently chosen from linear or branched, substituted or unsubstituted C1-12alkyl groups.

[0109] According to another example, R + is a group of formula -N + (RIR2R3), wherein R1, R2, and R3 are independently selected from linear or branched C1-12alkyl groups, or at least one of R1, R2, or R3 is substituted with a halogen atom or an alkoxyl, ether, ester, or siloxy group.

[0110] According to another example, R+ is a group of formula -N + (RIR2R3), wherein R1 and R2 together with the nitrogen atom form a single or multi-ring heterocycle having from 3 to 12 members and R3 is as previously defined, preferably R3 is a C1-12alkyl group or a C1-4alkyl group. In an example of interest, R3 is an unsubstituted C1-4alkyl group (such as methyl, ethyl, n- or i-propyl, n-, i-, s-, and t-butyl), and preferably R3 is a methyl group.

[0111] According to another example, R + is a group of formula -N+(R1R2R3), in which R1, R2, and R3 with the nitrogen atom together form a heteroaromatic or partially unsaturated heterocycle with one or more rings and having from 5 to 12 members.

[0112] According to another example, R + is chosen from: in which,

[0113] R3 is as previously defined, R4 is selected from a linear or branched, substituted or unsubstituted, preferably C1-4alkyl, C1-12alkyl, C1-12alkenyl and C1-12alkynyl group, R5 is a hydrogen atom or a linear or branched, substituted or unsubstituted, preferably C1-4alkyl, C1-12alkyl, C1-12alkenyl or C1-12alkynyl group, preferably R3 is an unsubstituted C1-4alkyl group (such as methyl, ethyl, n- or i-propyl, n-, i-, s-, and t-butyl, preferably methyl); and the heterocycle is optionally substituted.

[0114] According to another example, R + is a group of formula -P+(R1R2R3), in which R1, R2, and R3 are independently chosen from linear or branched, substituted or unsubstituted C1-12alkyl groups.

[0115] According to another example, R + is a group of formula -P +(RIR2R3), wherein R1, R2, and R3 are independently selected from linear or branched C1-12alkyl groups, or at least one of R1, R2, or R3 is substituted by a halogen atom or an alkoxyl, ether, ester, or siloxy group. In some examples, n may be a number in the range of 2 to 10, or 3 to 8, or 4 to 6, inclusive.

[0116] In some examples, the ionic bifunctional molecule is selected from 1,T-(1,6-hexamethylene) bis(1-methylpyrrolidinium) bis(trifluoromethanesulfonyl)imide, 1,1'-(1,12-dodecamethylene) bis(1-methylpyrrolidinium) bis(trifluoromethanesulfonyl)imide, 1,1'-(2,2'-(ethylenedioxy)diethane) bis(1-methylpyrrolidinium) bis(trifluoromethanesulfonyl)imide, 1,1'-(thiol bis(1,2-ethane)) bis(1-methylpyrrolidinium) bis(trifluoromethanesulfonyl)imide and 3,3'-(1,6-hexamethylene) bis(1,2-dimethylimidazolium) bis(trifluoromethanesulfonyl)imide. In an example of interest, the ionic bifunctional molecule is 1,1'-(1,6-hexamethylene) bis(l-methylpyrrolidinium) bis(trifluoromethanesulfonyl)imide.

[0117] The ionic bifunctional molecule may be present in the electrolyte at a concentration in the range of about 0.5 wt% to about 50 wt%, inclusive. For example, the ionic bifunctional molecule may be present in the electrolyte at a concentration in the range of about 2 wt% to about 30 wt%, or about 4 wt% to about 20 wt%, or about 5 wt% to about 15 wt%, inclusive.

[0118] The inorganic particles may be selected from any known inorganic solid electrolyte material particles and may be selected according to their compatibility with the various elements of an electrochemical cell. For example, the inorganic particles may comprise a material selected from glasses, glass-ceramics, ceramics, nanoceramics, and a combination of at least two of these.

[0119] In one example, the inorganic particles may comprise a fluoride, phosphide, sulfide, oxysulfide, or oxide-based ceramic, glass, or glass-ceramic.

[0120] In another example, the inorganic particles may comprise a LISICON, thio-LISICON, argyrodite, garnet, NASICON, perovskite, oxide, sulfide, oxysulfide, phosphide, fluoride compound in crystalline and / or amorphous form, or a combination of at least two thereof.

[0121] According to another example, the inorganic particles comprise a compound selected from inorganic compounds of formulas:

[0122] in which,

[0123] M is an alkali metal ion, an alkaline earth metal ion, or a combination thereof, and wherein when M comprises an alkaline earth metal ion, then the number of M is adjusted to achieve electroneutrality;

[0124] X is selected from F, Cl, Br, I or a combination of at least two thereof; a, b, c, d, e and f are non-zero numbers and are, independently in each formula, selected to achieve electroneutrality; and v, w, x, y and z are non-zero numbers and are, independently in each formula, selected to obtain a stable compound.

[0125] For example, M may be selected from Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, Ba or a combination of at least two of these. In a variant of interest, M is Li.

[0126] According to a variant of interest, the inorganic particles comprise an inorganic compound of formula MATP as defined herein.

[0127] According to another embodiment of interest, the inorganic particles comprise an argyrodite-type inorganic compound of formula Li6PS5X, wherein X is Cl, Br, I or a combination of at least two thereof. For example, the inorganic particles may comprise an inorganic compound of formula Li6PS5CI.

[0128] The inorganic particles may be present in the solid electrolyte at a concentration in the range of about 25 wt% to about 95 wt%, inclusive. For example, the inorganic particles may be present in the solid electrolyte at a concentration in the range of about 40 wt% to about 90 wt%, or about 60 wt% to about 90 wt%, inclusive.

[0129] The ratio of "inorganic particles: ionic bifunctional molecule" by weight may be in the range of 2:1 to 30:1, inclusive. For example, the ratio of "inorganic particles: ionic bifunctional molecule" by weight may be in the range of 3:1 to 20:1, or 5:1 to 15:1, inclusive.

[0130] The solid electrolyte as defined herein may further include a polymer. For example, the polymer may be chosen for its compatibility with the various elements of an electrochemical cell. Any known compatible polymer is considered. The polymer may be chosen from linear or branched polymers.Non-limiting examples of polymers include polyethers (e.g., a polyether based on polyethylene oxide (PEO), polypropylene oxide (POP), or a combination of both (such as an EO / PO copolymer)), polythioethers, polyesters, polythioesters, polydimethylsiloxanes, polyalkylene carbonates, polyalkylene thiocarbonates, polyalkylene sulfones, polyalkylene sulfonamides, polyimides, polyamides, polyphosphazenes, polyurethanes, polyvinyl alcohols, polyacrylonitriles, polyethacrylates and polymethacrylates, and copolymers thereof, optionally comprising crosslinked units derived from crosslinkable functional groups (such as acrylate, methacrylate, vinyl, glycidyl, mercapto, etc.) or their cross-linked equivalents.

[0131] According to one example, the polymer, if present in the electrolyte, may be the product of the reaction between at least one monomer comprising at least one polymerizable or crosslinkable functional group and a compound comprising at least one SH functional group.

[0132] In another example, the polymer may be present in the solid electrolyte at a concentration in the range of about 0.1 wt% to about 20 wt%, inclusive. For example, the polymer may be present in the solid electrolyte at a concentration in the range of about 1 wt% to about 15 wt%, or about 2 wt% to about 10 wt%, inclusive.

[0133] For example, the ionic bifunctional molecule as defined herein acts as a binder between the inorganic particles in the solid electrolyte as defined herein, the binder thus also being able to further comprise the polymer as defined herein.

[0134] The solid electrolyte as defined herein may also optionally include an additive.

[0135] According to one example, the additive, if present in the electrolyte, may be a fluorinated compound comprising an amide function. The fluorinated compound may be of formula R 6 X 6 C(O)N(H)X 7 R 7 , where R 6 and R 7 are independently alkyl, cycloalkyl, heterocycloalkyl, aryl, or heteroaryl groups, X 6 is O, NH or absent, and X 7 is absent or is a C(O), S(O)2, or Si(R) group 8 R 9 ), where R 8 and R 9 are alkyl groups, and where at least one of R 6 , R 7, R 8 and R 9 is a group substituted by one or more fluorine atom(s). For example, R 6 is a perfluorinated group and X 6 is absent.

[0136] In one example, the additive, if present in the electrolyte, may be present in the solid electrolyte at a concentration in the range of about 5 wt% to about 40 wt%, inclusive. For example, the additive may be present in the solid electrolyte at a concentration in the range of about 10 wt% to about 35 wt%, or about 15 wt% to about 30 wt%, inclusive.

[0137] The present technology also relates to an electrochemical cell comprising a negative electrode, a positive electrode and an electrolyte, wherein the electrolyte is as defined herein.

[0138] The positive electrode comprises a positive electrode material optionally on a current collector. The positive electrode material comprises an electrochemically active positive electrode material. Non-limiting examples of electrochemically active positive electrode materials include metal phosphates, lithium metal phosphates, metal oxides, and lithium metal oxides.

[0139] For example, the metal of the electrochemically active material may be selected from titanium (Ti), iron (Fe), magnesium (Mg), manganese (Mn), vanadium (V), nickel (Ni), cobalt (Co), aluminum (Al), chromium (Cr), copper (Cu), antimony (Sb) and a combination of at least two of these, when compatible. According to a variant of interest, the metal of the electrochemically active material may be selected from titanium (Ti), iron (Fe), magnesium (Mg), manganese (Mn), vanadium (V), nickel (Ni), cobalt (Co), aluminum (Al) and a combination of at least two of these, when compatible.

[0140] Non-limiting examples of electrochemically active positive electrode materials generally include metal phosphates and lithiated metal phosphates (e.g., LiM'PCL and M'PCL, where M' is selected from Fe, Ni, Mn, Co, and a combination of at least two thereof), vanadium oxides and lithium vanadium oxides (e.g., LiV3O8, V2O5, LiV2O5, and other similar vanadium oxides and lithium vanadium oxides), and lithium metal oxides of the formulae LiMn2C>4, LiM”C>2 (where M” is selected from Mn, Co, Ni, and a combination of at least two thereof) (such as NMC, LiMn x Co y Neither zO2 withx+y+z = 1), Li(NiM”')C>2 (where M'" is selected from Mn, Co, Al, Fe, Cr, Ti, Zr, another similar metal and a combination of at least two of these), sulfur, elemental selenium or iodine, iron(lll) fluoride, copper(lll) fluoride, lithium iodide, carbon-based active materials such as graphite, organic cathode active materials, or a combination of at least two of these electrochemically active materials, when compatible with each other.

[0141] The positive electrode material as defined herein may further include an electronically conductive material, a binder, a salt, an ionic bifunctional molecule (e.g., an ionic bifunctional molecule as defined above), and / or inorganic particles.

[0142] The negative electrode comprises an electrochemically active negative electrode material which is optionally on a current collector. In one example, the electrochemically active negative electrode material may comprise a metal film comprising an alkali or alkaline earth metal or an alloy comprising an alkali or alkaline earth metal. For example, the alkali metal may be selected from lithium and sodium.

[0143] In another example, the negative electrode electrochemically active material may include an intermetallic compound (e.g., SnSb, TiSnSb, Cu2Sb, AlSb, FeSb2, FeSn2, and CoSn2), a metal oxide, a metal nitride, a metal phosphide, a metal phosphate (e.g., LiTi2(PO4)3), a metal halide (e.g., a metal fluoride), a metal sulfide, a metal oxysulfide, a carbon (e.g., graphite, graphene, reduced graphene oxide, hard carbon, soft carbon, exfoliated graphite, and amorphous carbon), silicon (Si), a silicon-carbon composite (Si-C), a silicon oxide (SiO x ), a silicon oxide-carbon composite (SiOx-C), tin (Sn), a tin-carbon composite (Sn-C), a tin oxide (SnO x ), a tin oxide-carbon composite (SnO x-C), and a combination of at least two of these, when compatible. For example, the metal oxide may be selected from compounds of formulae or a combination thereof; and b and c are numbers such that the c:b ratio is in the range 2 to 3) (e.g., MoO3, MoO2, MoS2, V2O5, and TiNb2O7), spinel oxides or a combination thereof) (by example, a lithium titanate (such as Li4Ti5O12) or a lithium molybdenum oxide (such as Li2MO4O13)).

[0144] In another example, the negative electrode material may further comprise an electronically conductive material, a binder, a salt, an ionic bifunctional molecule (e.g., an ionic bifunctional molecule as defined above), and / or inorganic particles.

[0145] The present technology also relates to a battery comprising at least one electrochemical cell as defined herein. For example, said battery is selected from the group consisting of a lithium battery, a lithium-ion battery, a sodium battery, a sodium-ion battery, a potassium battery, a potassium-ion battery, a magnesium battery, and a magnesium-ion battery. According to a variant of interest, said battery is a lithium battery or a lithium-ion battery. The presence of the ionic bifunctional molecule as defined herein in a solid electrolyte, for example, in an inorganic solid electrolyte or a polymer-ceramic hybrid solid electrolyte can significantly improve some of its physical and / or electrochemical properties.

[0146] In one example, the presence of the ionic bifunctional molecule may, for example, substantially improve the mechanical strength of a solid electrolyte film and / or the densification of said solid electrolyte film after creep. In another example, the presence of the ionic bifunctional molecule may substantially improve the ionic conductivity and / or electrochemical stability of the solid electrolyte film. In some cases, the presence of the ionic bifunctional molecule may also substantially improve the flammability safety of the solid electrolyte film.

[0147] EXAMPLES

[0148] The following examples are for illustrative purposes and should not be construed as further limiting the scope of the invention as contemplated. These examples will be better understood by reference to the accompanying Figures.

[0149] Example 1 - Preparation and characterization of bifunctional ionic salts a) Preparation of 1,1'-(1,6-hexamethylene) bis(l-methylpyrrolidinium) dibromide

[0150] 8 g of 1-methylpyrrolidine (94.1 mmol), 10.4 g of 1,6-dibromohexane (42.8 mmol) and 20 ml of tetrahydrofuran (THF) were introduced into a 100 ml single-necked flask. The solution was heated at a temperature of about 50 °C for about 12 hours. The precipitate formed during the reaction was then collected by filtration and washed three times with THF. The product thus obtained was dried under vacuum at a temperature of about 50 °C for about 24 hours. b) Preparation of 1,1'-(1,6-hexamethylene) bis(trifluoromethanesulfonyl)imide bis(1-methylpyrrolidinium) (Salt 1) Salt 1

[0151] 1,1'-(1,6-Hexamethylene)bis(1-methylpyrrolidinium)bis(trifluoromethanesulfonyl)imide (Salt 1) was prepared by anion exchange from lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and 1,1'-(1,6-hexamethylene)bis(1-methylpyrrolidinium) dibromide prepared in Example 1(a). The anion exchange was carried out in water at a temperature of about 40 °C for about 3 hours. c) Preparation of 1,1'-(1,12-dodecamethylene)bis(1-methylpyrrolidinium) dibromide

[0152] 8 g of 1-methylpyrrolidine (94.1 mmol), 10.3 g of 1,12-dibromododecane (31.4 mmol) and 20 ml of THF were introduced into a 100 ml single-necked flask. The solution was heated at a temperature of about 50 °C for about 12 hours. The precipitate formed during the reaction was then collected by filtration and washed three times with diethyl ether. The product thus obtained was dried under vacuum at a temperature of about 50 °C for about 24 hours. d) Preparation of bis(trifluoromethanesulfonyl)imide of dodecamethylene) bis(l-methylpyrrolidinium) (Salt 2)

[0153] Salt 2

[0154] 1,1'-(1,12-dodecamethylene) bis(1-methylpyrrolidinium) bis(trifluoromethanesulfonyl)imide (Salt 2) was prepared by anion exchange from LiTFSI and 1,1'-(1,12-dodecamethylene) bis(1-methylpyrrolidinium) dibromide prepared in Example 1(c). The anion exchange was carried out in water at a temperature of about 40°C for about 3 hours. e) Preparation of 1,1'-(2,2'-(ethylenedioxy)diethane) bis(1-methylpyrrolidinium) dichloride

[0155] 4 g of 1-methylpyrrolidine (46.6 mmol), 2.9 g of 1,2-bis(2-chloroethoxy)ethane (15.6 mmol) and 10 ml of THF were introduced into a 50 ml single-necked flask. The solution was heated at a temperature of about 50 °C for about 48 hours. The precipitate formed during the reaction was then collected by filtration and washed three times with diethyl ether. The product thus obtained was dried under vacuum at a temperature of about 50 °C for about 24 hours. f) Preparation of 1,1'-(2,2'-)bis(trifluoromethanesulfonyl)imide

[0156] (ethylenedioxy)diethane) bis(1-methylpyrrolidinium) (Salt 3)

[0157] Salt 3

[0158] 1,1'-(2,2'-(ethylenedioxy)diethane) bis(1-methylpyrrolidinium) bis(trifluoromethanesulfonyl)imide (Salt 3) was prepared by anion exchange from LiTFSI and 1,1'-(2,2'-(ethylenedioxy)diethane) bis(1-methylpyrrolidinium) dichloride prepared in Example 1(e). The anion exchange was carried out in water at a temperature of about 40 °C for about 3 hours. g) Preparation of 1-(2-hydroxyethyl)-1-methylpyrrolidinium iodide

[0159] 5.75 g of 1-(2-hydroxyethyl)pyrrolidine (50 mmol), 8.52 g of iodomethane (60 mmol) and 10 ml of THF were introduced into a 50 ml single-necked flask. The solution was heated at a temperature of about 50 °C for about 12 hours. The precipitate formed during the reaction was then collected by filtration and washed three times with diethyl ether. The product thus obtained was dried under vacuum at a temperature of about 50 °C for about 24 hours. h) Preparation of 1-(2-chloroxyethyl)-1-methylpyrrolidinium iodide

[0160] 5.14 g of 1-(2-hydroxyethyl)-1-methylpyrrolidinium iodide prepared in Example 1(g) (20 mmol), 23.8 g of thionyl dichloride (0.2 mol) were introduced into a 50 ml single-necked flask. The solution was heated at a temperature of about 70 °C for about 24 hours. The product was precipitated in 100 ml of diethyl ether. The precipitate was then collected by filtration and washed three times with diethyl ether. The product thus obtained was dried under vacuum at a temperature of about 50 °C for about 24 hours. i) Preparation of 1, 1'-(thiol bis(1,2-ethane)) bis(1-methylpyrrolidinum) iodide

[0161] 3 g of 1-(2-chloroxyethyl)-1-methylpyrrolidinium prepared in Example 1 (h) (11 mmol), 0.43 g of sodium sulfide (5.5 mmol), 0.04 g of sodium hydroxide (1 mmol), 40 ml of deionized water and 60 ml of methanol were introduced into a 250 ml single-necked flask. The solution was heated at a temperature of about 50 °C for about 24 hours. The precipitate formed during the reaction was then collected by filtration and washed three times with diethyl ether. The product thus obtained was dried under vacuum at a temperature of about 50 °C for about 24 hours. j) Preparation of 1,1'-(thiol bis(1,2-ethane)) bis(1-methylpyrrolidinum) bis(trifluoromethanesulfonyl)imide (Salt 4)

[0162] Salt 4

[0163] 1,1'-(thiol bis(1,2-ethane)) bis(1-methylpyrrolidinum) bis(trifluoromethanesulfonyl)imide (Salt 4) was prepared by anion exchange from LiTFSI and 1,1'-(thiol bis(1,2-ethane)) bis(1-methylpyrrolidinum) iodide prepared in Example 1(i). The anion exchange was carried out in water:methanol (2:8 by volume) at a temperature of about 40 °C for about 3 hours. k) Preparation of 3,3'-(1,6-hexamethylene) bis(1,2-dimethylimidazolium) dibromide

[0164] 5.77 g of 1,2-dimethylimidazole (60 mmol), 4.88 g of 1,6-dibromohexane (20 mmol) and 10 ml of THF were introduced into a 50 ml single-necked flask. The solution was heated at a temperature of about 50 °C for about 12 hours. The precipitate formed during the reaction was then collected by filtration and washed three times with diethyl ether. The product thus obtained was dried under vacuum at a temperature of about 50 °C for about 24 hours. l) Preparation of 3,3'-(1,6-hexamethylene) bis(1,2-dimethylimidazolium) bis(trifluoromethanesulfonyl)imide (Salt 5)

[0165] Salt 5

[0166] 3,3'-(1,6-Hexamethylene)bis(1,2-dimethylimidazolium)bis(trifluoromethanesulfonyl)imide (Salt 5) was prepared by anion exchange from LiTFSI and 3,3'-(1,6-hexamethylene)bis(1,2-dimethylimidazolium) dibromide prepared in Example 1(k). The anion exchange was carried out in water at a temperature of about 40 °C for about 3 hours.

[0167] Example 2 - Characterization by nuclear magnetic resonance (NMR)

[0168] Salts 1 to 5 prepared in Example 1 were characterized by proton nuclear magnetic resonance ( 1 H NMR). a) Characterization by 1 H NMR of Salt 1 prepared in Example 1(b)

[0169] The Spectrum 1 H NMR of Salt 1 prepared in Example 1(b) was obtained in methanol-d4 (deuterated methanol or CD3OD) as solvent and the results obtained are shown in Table 1. Table 1. Results 1 H NMR obtained for Salt 1 b) Characterization by 1 H NMR of Salt 2 prepared in Example 1(d)

[0170] The Spectrum 1 H NMR of Salt 2 prepared in Example 1(d) was obtained in chloroform-d (deuterated chloroform or CDCl3) as solvent and the results obtained are shown in Table 2. Table 2. Results 1 H NMR obtained for Salt 2 c) Characterization by 1 H NMR of Salt 3 prepared in Example 1(f)

[0171] The Spectrum 1 H NMR of Salt 3 prepared in Example 1(f) was obtained in CDCh as solvent and the results obtained are shown in Table 3. Table 3. Results 1 H NMR obtained for Salt 3 d) Characterization by 1 H NMR of Salt 4 prepared in Example 1(j)

[0172] The Spectrum 1H NMR of Salt 4 prepared in Example 1(j) was obtained in dimethyl sulfoxide-d6 (deuterated dimethyl sulfoxide or DMSO-d6) as solvent and the results obtained are shown in Table 4. Table 4. Results 1 H NMR obtained for Salt 4 e) Characterization by 1 H NMR of Salt 5 prepared in Example 1(1)

[0173] The Spectrum 1 H NMR of Salt 5 prepared in Example 1(1) was obtained in DMSO-d6 as solvent and the results obtained are shown in Table 5. Table 5. Results 1 H NMR obtained for Salt 5

[0174] Example 3 - Thermal and thermogravimetric analyses

[0175] Figure 1 shows the results of Differential Scanning Calorimetry (DSC) analysis obtained for Salts 1, 2, 4 and 5 prepared in Examples 1(b), 1(d) and 1(1), respectively. The DSC analysis was carried out over a temperature range of about -20°C to about 148°C at a heating rate of 10°C / min. As shown in Figure 1, Salt 1 has a crystallization temperature of -11°C and a melting temperature of 63°C. Figure 2 shows the results of thermogravimetric analysis (TGA) obtained for Salts 1 to 5 prepared in Examples 1(b), 1(d), 1(f), 1(j) and 1(1), respectively. Thermogravimetric analysis was carried out over a temperature range from about 40 °C to about 600 °C. As shown in Figure 2, Salt 1 has a decomposition point around 295 °C.The results of thermal and thermogravimetric analyses are presented in Table 6.

[0176] Table 6. DSC and TGA results obtained for Salts 1 to 5

[0177] *ND: Not detectable between approximately -50°C and approximately 150°C

[0178] Example 4 - Chemical and Electrochemical Stability The electrochemical stability of a liquid electrolyte comprising Salt 1 prepared in Example 1(b) was characterized by linear sweep voltammetry (LSV) and cyclic voltammetry (CV). a) Cell Configurations for Electrochemical Stability Analyses

[0179] A liquid electrolyte comprising LiTFSI, TEGDME as a solvent and Salt 1 prepared in Example 1(b) was prepared. A liquid electrolyte comprising LiTFSI and TEGDME and a liquid electrolyte comprising LiTFSI, TEGDME and [PYR1,4]TFSI were also prepared for comparison. The composition of the liquid electrolytes for electrochemical stability analyses is shown in Table 7.

[0180] Table 7. Composition of liquid electrolytes

[0181] Celgard separators MC 2325 made of a microporous polypropylene-polyethylene-polypropylene (PP / PE / PP) trilayer membrane with a thickness of about 25 μm were impregnated with the above liquid electrolytes. Discs with a diameter of 16 mm were then cut from the liquid electrolyte-impregnated membranes.

[0182] The cells for electrochemical stability analyses were assembled according to the following procedure. The cell assembly was carried out in a button cell configuration. The liquid electrolyte-impregnated discs prepared in the present example were placed and pressed between an aluminum electrode and a lithium electrode for the oxidation process (Al / electrolyte / Li) and between a copper electrode and a lithium electrode for the reduction process (Cu / electrolyte / Li).

[0183] The configuration of each cell is presented as follows:

[0184] Cell 1: Electrode / E1 / Electrode

[0185] Cell 2: Electrode / E2 / Electrode

[0186] Cell 3: Electrode / E3 / Electrode b) Electrochemical stability analyses

[0187] Electrochemical stability measurements for Cells 1 to 3 assembled in Example 4(a) were performed by LSV. Electrochemical stability measurements for cells comprising electrolytes E2 and E3 were also performed by CV. The measurements were performed with a Bio-Logic system. MC VMP-300 at a scan rate of 0.1 mV / s.

[0188] Figures 3 and 4 show the results of LSV and CV analysis, respectively. As shown in Figures 3 and 4, Cell 3 comprising the liquid electrolyte comprising LiTFSI, TEGDME and Salt 1 prepared in Example 1(b) has higher electrochemical stability than Cell 2 comprising the liquid electrolyte comprising LiTFSI, TEGDME and [PYR1,4]TFSI. c) Chemical Stability Analyses

[0189] The chemical stability of TEGDME, a solution comprising [PYRI,4]TFSI in TEGDME and a solution comprising Salt 1 prepared in Example 1(b) in TEGDME towards metallic lithium was analyzed.

[0190] Figure 5 shows images of lithium foils soaked respectively in (A) in TEGDME, in (B) in a solution comprising [PYRI,4]TFSI in TEGDME in a ratio of TEGDME:[PYRI,4]TFSI (40:60 by weight), and in (C) in a solution comprising Salt 1 prepared in Example 1(b) in TEGDME in a ratio of TEGDME:Salt 1 (41:59 by weight). The lithium foils were submerged in the three different solutions for about one week. As shown in Figure 5, only the solution comprising [PYRI,4]TFSI in TEGDME changed color from transparent to black (Figure 5(B)). This indicates that the chemical stability of TEGDME and the solution comprising Salt 1 in TEGDME is higher than that of the solution comprising [PYRI,4]TFSI in TEGDME.

[0191] Example 5 - Preparation and characterization of an inorganic solid electrolyte a) Preparation of an inorganic solid electrolyte pellet

[0192] 0.294 g of Lii.3Alo.3Tii.7(PO4)3 (LATP, Toshima MC ), 0.126 g of / V-methyltrifluoroacetamide

[0193] (NMTFAm) and 0.06 g of Salt 1 prepared in Example 1(b) were well mixed and ground in a mortar at room temperature to obtain a solid electrolyte powder. Round pellets having a diameter of about 16 mm and a thickness of about 900 μm were obtained by compressing the solid electrolyte powder under a pressure of 120 psi.

[0194] Figure 6 shows images of a solid electrolyte pellet showing respectively in (A) its diameter (about 16 mm), and in (B) its thickness (about 900 pm). b) Ionic conductivity

[0195] The ionic conductivity of the inorganic solid electrolyte pellets prepared in Example 5(a) was characterized by electrochemical impedance spectroscopy.

[0196] To do this, the inorganic solid electrolyte pellets prepared in Example 5(a) were placed and pressed between two stainless steel electrodes.

[0197] Electrochemical impedance spectroscopy measurements were performed using a Bio-Logic system MC VMP-300 with an amplitude of 100 mV and a frequency range from 1 MHz to 200 mHz. An ionic conductivity of 2.5 mS / cm was measured at a temperature of 60 °C.

[0198] Example 6 - Preparation and characterization of ceramic-ionic plastic salt composite solid electrolyte films

[0199] The crosslinkable polymer used in the following example is a multi-branched polyether comprising crosslinkable units, as described in U.S. Patent No. 7,897,674 (hereinafter referred to as "polymer US'674").

[0200] The ionic plastic crystal used in the following example is an ionic plastic crystal including a delocalized bis(trifluoromethanesulfonyl)imide [TFSI]' anion paired with a cation derived from 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), as described in PCT patent application published under the number WO 2022 / 165598 (hereinafter referred to as "plastic crystal WO'598"). a) Preparation of ceramic-ionic plastic salt composite solid electrolyte films Composite solid electrolyte films comprising a sulfide-based ceramic and Salt 1 prepared in Example 1(b) were prepared. Composite solid electrolyte films comprising a sulfide-based ceramic and plastic crystal WO'598 were also prepared for comparison.

[0201] All manipulations were carried out in a glove box under an argon atmosphere (0.1 ppm H2O; 0.1 ppm O2).

[0202] Two sizes (about 3 pm and less than 1 pm) of sulfide-based ceramic-type inorganic solid electrolyte (LiePSsCI) particles were mixed in mass proportion of 90:10 or 75:25 using a vortex mixer.

[0203] The binder used comprises a 40:60 mixture by mass of the polymer US'674 at 0.5% by mass of UV crosslinker and the plastic crystal WO'598 or one of Salts 1 to 5 was dissolved in dichloromethane (DCM). For binders comprising Salts 4 and 5, a small amount of acetone was added to obtain good dissolution of the salt.

[0204] The weight ratio of sulfide to binder was 90:10 by mass. The amount of DCM or DCM and acetone was adjusted to obtain a mixture with an appropriate viscosity. The resulting mixture was coated onto a previously degreased aluminum foil. The resulting film was dried in a glove box. After drying, UV crosslinking was performed for approximately 15 seconds.

[0205] The composition of the ceramic-ionic plastic salt composite solid electrolyte films is shown in Table 8.

[0206] Table 8. Composition of ceramic-plastic ionic salt composite solid electrolyte films b) Ionic conductivity of ceramic-plastic ionic salt composite solid electrolyte films

[0207] Pellets of 10 mm diameter were taken from the ceramic-ionic plastic salt composite solid electrolyte films prepared in Example 6(a). The pellets were placed in a 10 mm diameter mold and compressed under a pressure of 2.8 tons using a press. The pellets were then placed in a conductivity cell at a pressure of 5 MPa closed under an inert argon atmosphere. The configuration of each cell is shown as follows:

[0208] Cell 4: Electrode / E4 / Electrode

[0209] Cell 5: Electrode / E5 / Electrode

[0210] Cell 6: Electrode / E6 / Electrode

[0211] Cell 7: Electrode / E7 / Electrode

[0212] Cell 8: Electrode / E8 / Electrode

[0213] Cell 9: Electrode / E9 / Electrode

[0214] Cell 10: Electrode / E10 / Electrode

[0215] Cell 11: Electrode / E11 / ElectrodeThe ionic conductivity measurements of the cells assembled in this example were carried out with a VMP-300 multichannel potentiostat (Bio-Logic MC ). The measurements were carried out over a frequency range from 7 MHz to 200 mHz under an amplitude of 50 mV in a temperature range from -10°C to 70°C (rising every 10°C) and in a temperature range from 70°C to 20°C (descending every 10°C).

[0216] Impedance measurements were obtained after stabilization for approximately one hour. Two impedance measurements were recorded at each temperature with 15 minutes between each measurement. Figure 7 shows the results of measured ionic conductivity as a function of temperature for the Cells. Figure 8 presents the results of ionic conductivity measured as a function of temperature for the Cells It can be observed in Figure 7 that the ionic conductivity of Cells 5 and 7 is lower than that of Cells 4 and 6 comprising respectively mass proportions of Li6PSsCI (3 m : < 1 pm) of 75 : 25 and 90 : 10.

[0217] Figure 7 shows that the ionic conductivity of Cells 6 and 7 is substantially higher than that of Cells 4 and 5 comprising ceramic-ionic plastic salt composite solid electrolyte films including Salt 1 and the plastic crystal WO'598, respectively. This indicates better interaction of lithium ions from the sulfide-based ceramic-type inorganic solid electrolytes with the bifunctional ionic salt.

[0218] Figure 7 also shows that the ionic conductivity of Cell 7 (mass ratio of Li6PSsCI (3 pm: < 1 pm) of 75:25) including Salt 1 is similar to that of Cell 4 (mass ratio of LiePSsCI (3 pm: < 1 pm) of 90:10) with the WO'598 plastic crystal. This indicates that the bifunctional ionic salt allows for increased addition of smaller sized LiePSsCI particles (< 1 pm) and thus for obtaining better compactness of the ceramic-ionic plastic salt composite solid electrolyte film under compression while maintaining substantially high performance.

[0219] At a temperature of 20 °C, the ionic conductivity results for Cells 6 and 7 are slightly lower than those obtained for compressed inorganic solid electrolyte particles of the sulfide-based ceramic type (Li6PSsCI) alone and without aluminum support, but measured under the same conditions.

[0220] It can be observed in Figure 8 that the ionic conductivities obtained for Cells 8, 9 and 11 comprising ceramic-ionic plastic salt composite solid electrolyte films including Salts 2, 3 and 5 respectively are higher than that obtained for Cell 10 comprising a ceramic-ionic plastic salt composite solid electrolyte film including Salt 4. c) Characterization of the ceramic-ionic plastic salt composite solid electrolyte films by scanning electron microscopy (SEM)

[0221] Figure 9 shows SEM images obtained in (A) before creep, and in (B) and (C) after creep at a temperature of about 70°C for the ceramic-ionic plastic salt composite solid electrolyte film E6 prepared in Example 6(a). Figure 9(A) shows that after compression, but before creep, the ceramic-ionic plastic salt composite solid electrolyte film is substantially dense and has a thickness of about 40 μm. It is possible to distinguish the individual sulfide-based ceramic particles and / or agglomerates.

[0222] Figures 9(B) and (C) show the effect of creep at a temperature of 70°C (above the melting temperature of Salt 1) and back down to room temperature. It can be observed that after creep, the ceramic-ionic plastic salt composite solid electrolyte film is substantially denser and no longer presents agglomerates. This can be useful in so-called "all-solid" configurations, especially in lithium metal configurations in order to resist lithium dendrites.

[0223] Example 7 - Preparation and characterization of ceramic-ionic plastic salt composite solid electrolyte films (4,4'-thiobisbenzenethiol (TBT) crosslinking) a) Preparation of ceramic-ionic plastic salt composite solid electrolyte films and TBT crosslinking

[0224] All manipulations were carried out in a glove box under an argon atmosphere (0.1 ppm H2O; 0.1 ppm O2).

[0225] Two sizes (about 3 pm and less than 1 pm) of sulfide-based ceramic-type inorganic solid electrolyte (Li6PS5CI) particles were mixed in a mass ratio of 90:10 using a vortex mixer.

[0226] The binder used comprises a 40:60 by mass mixture of the US'674 polymer at 4.0% by mass of TBT and Salt 1 prepared in Example 1(b) dissolved in DCM.

[0227] The weight ratio of sulfide to binder was 90:10 by mass. The amount of DCM was adjusted to obtain a mixture with an appropriate viscosity. The resulting mixture was coated onto a previously degreased aluminum foil. The resulting film was dried in a glove box.

[0228] The composition of ceramic-ionic plastic salt composite solid electrolyte films is shown in Table 9. Table 9. Composition of ceramic-ionic plastic salt composite solid electrolyte films b) Ionic conductivity of polymer-ceramic hybrid solid electrolyte films

[0229] Pellets of 10 mm diameter were taken from the ceramic-ionic plastic salt composite solid electrolyte films prepared in Example 7(a). The pellets were placed in a 10 mm diameter mold and compressed under a pressure of 2.8 tons using a press. The pellets were then placed in a conductivity cell at a pressure of 5 MPa closed under an inert argon atmosphere. The configuration of each cell is shown as follows:

[0230] Cell 12: Electrode / E12 / Electrode

[0231] Cell 13: Electrode / E13 / Electrode

[0232] Ionic conductivity measurements of the cells assembled in the present example were carried out with a VMP-300 multichannel potentiostat (Bio-Logic MC). The measurements were carried out over a frequency range from 7 MHz to 200 mHz under an amplitude of 50 mV in a temperature range from -10°C to 70°C (rising every 10°C) and in a temperature range from 70°C to 20°C (descending every 10°C).

[0233] Impedance measurements were obtained after stabilization for approximately one hour. Two impedance measurements were recorded at each temperature with 15 minutes between each measurement. Figure 10 shows the results of measured ionic conductivity as a function of temperature for Cells 12 (•) and 13 (▼).

[0234] Crosslinking the US'674 polymer via the insertion of TBT between the US'674 polymer chains inhibits the ionic conduction of lithium ions through the US'674 polymer and therefore significantly increases the ionic conduction of ceramic-ionic plastic salt composite solid electrolyte films, especially after the creep of Salt 1. This confirms the interaction between the ionic plastic salt and sulfide-based ceramics (such as Li6PSsCI) as well as the positive effect of the creep of the ionic plastic salt on the density of the resulting film and on its ionic conductivity. The ionic conductivity of the ceramic-ionic plastic salt-TBT composite solid electrolyte film is substantially identical to that obtained for an inorganic solid electrolyte film of sulfide-based ceramic type (Li6PSsCI).

[0235] Several modifications could be made to any of the embodiments described above without departing from the scope of the present invention as contemplated. The references, patents or scientific literature documents referred to in this application are incorporated herein by reference in their entirety and for all purposes.

Claims

CLAIMS A solid electrolyte comprising inorganic particles and a bifunctional ionic molecule of Formula I or II: Formula II in which, A- is a delocalized anion; R + is chosen from the -N+(R1R2R3) and -P+(R1R2R3) groups excluding cations derived from the superbases amidines, guanidines and phosphazenes; Ri, R2, and R3 are independently chosen from a linear or branched C1-12alkyl group, substituted or unsubstituted; or Ri and R2 with the nitrogen or phosphorus atom together form a heterocycle with one or more rings and having from 3 to 12 members and R3 is as previously defined; or Ri, R2, and R3 with the nitrogen or phosphorus atom together form a partially unsaturated heteroaromatic or heterocycle with one or more rings and having from 5 to 12 members; L is a linear or branched C2-4 alkylene; X is O or S; m is a number in the range of 1 to 6; and n is a number in the range of 1 to 11. Solid electrolyte according to claim 1, wherein the delocalized anion is selected from hexafluorophosphate (PF6-), bis(trifluoromethanesulfonyl)imidide (TFSI-), bis(fluorosulfonyl)imidide (FSh), the (fluorosulfonyl)(trifluoromethanesulfonyl)imidide (FTFSh), 2-trifluoromethyl-4,5- dicyanoimidazolate (TDI), 4,5-dicyano-1,2,3-triazolate (DCTA'), bis(pentafluoroethylsulfonyl)imidide (BEIT), difluorophosphate (DFP'), tetrafluoroborate (BF4'), bis(oxalato)borate (BOB'), nitrate (NO3-), perchlorate (ClO4-), hexafluoroarsenate (AsF6-), trifluoromethanesulfonate (CF3SC3- or 'OTf'), fluoroalkylphosphate ([PF3(CF2CF3)3]' or FAP'), tetrakis(trifluoroacetoxy)borate ([B(OCOCF3)4]' or TFAB'), bis(1,2-benzenediolato(2-)-O,O')borate ([B(C6O2)2]' or BBB'), difluoro(oxalato)borate (BF2(C2O4)' or FOB'), and an anion of formula BF2O4R X (R X = C 2-4 alkyl).

3. Solid electrolyte according to claim 2, wherein the delocalized anion is selected from hexafluorophosphate (PF6-), bis(trifluoromethanesulfonyl)imidide (TFSI'), bis(fluorosulfonyl)imidide (FSI), the (fluorosulfonyl)(trifluoromethanesulfonyl)imidide (FTFSI'), tetrafluoroborate (BF4'), and trifluoromethanesulfonate (CFsSOs' or 'OTf).

4. Solid electrolyte according to claim 3, wherein the delocalized anion is bis(trifluoromethanesulfonyl)imidide (TFSI').

5. Solid electrolyte according to any one of claims 1 to 4, wherein R + is a grouping -NXR1R2R3).

6. Solid electrolyte according to claim 5, wherein Ri, R2, and R3 are independently selected from linear or branched, substituted or unsubstituted C1-12alkyl groups.

7. Solid electrolyte according to claim 5, wherein Ri, R2, and R3 are independently selected from linear or branched C1-12alkyl groups, or at least one of Ri, R2, or R3 is substituted with a halogen atom or an alkoxyl, ether, ester, or siloxy group.

8. Solid electrolyte according to claim 5, wherein Ri and R2 with the nitrogen atom together form a heterocycle with one or more rings and having from 3 to 12 members and R3 is as defined in claim 1, preferably R3 is a C1-12alkyl, or a C1-4alkyl.

9. Solid electrolyte according to claim 5, wherein Ri, R2, and R3 with the nitrogen atom together form a partially unsaturated heteroaromatic or heterocycle with one or more rings and having from 5 to 12 members.

10. Solid electrolyte according to claim 5, wherein R + is chosen from in which R3 is as defined in claim 1, R4 is a linear or branched C1-12alkyl, C1-12alkenyl or C1-12alkynyl group, substituted or unsubstituted, R5 is a hydrogen atom or a linear or branched C1-12alkyl, C1-12alkenyl or C12 12alkynyl group, substituted or unsubstituted, and the heterocycle is optionally substituted.

11. Solid electrolyte according to claim 10, wherein R4 is a Ci-4 alkyl group.

12. Solid electrolyte according to claim 10 or 11, wherein R5 is a C1-4 alkyl group.

13. Solid electrolyte according to any one of claims 10 to 12, wherein R3 is an unsubstituted C1-4alkyl group.

14. Solid electrolyte according to claim 13, wherein R3 is selected from a methyl group, an ethyl group, an n- or i-propyl group, and an n-, i-, s- or t-butyl group.

15. Solid electrolyte according to any one of claims 1 to 4, wherein R + is a grouping -P + (R1R2R3) .

16. Solid electrolyte according to claim 15, wherein Ri, R2, and R3 are independently selected from linear or branched, substituted or unsubstituted C1-12alkyl groups.

17. Solid electrolyte according to claim 15, wherein Ri, R2, and R3 are independently selected from linear or branched C1-12alkyl groups, or at least one of Ri, R2, or R3 is substituted with a halogen atom or an alkoxyl, ether, ester, or siloxy group.

18. Solid electrolyte according to any one of claims 1 to 17, in which n is a number in the range of 2 to 10, or 3 to 8, or 4 to 6.

19. Solid electrolyte according to claim 1, wherein the ionic bifunctional molecule is the bis(trifluoromethanesulfonyl)imidide of 1,1'-(1,6-hexamethylene) bis(l-methylpyrrolidinium).

20. Solid electrolyte according to claim 1, wherein the ionic bifunctional molecule is the bis(trifluoromethanesulfonyl)imidide of 1,1'-(1,12-dodecamethylene) bis(l-methylpyrrolidinium).

21. Solid electrolyte according to claim 1, wherein the ionic bifunctional molecule is bis(trifluoromethanesulfonyl)imidide of 1,1'-(2,2'-(ethylenedioxy)diethane)bis(l-methylpyrrolidinium).

22. Solid electrolyte according to claim 1, wherein the ionic bifunctional molecule is bis(trifluoromethanesulfonyl)imidide of 1,1'-(thiol bis(1,2-ethane)) bis(l-methylpyrrolidinum).

23. Solid electrolyte according to claim 1, wherein the ionic bifunctional molecule is 3,3'-(1,6-hexamethylene) bis(1,2-dimethylimidazolium)imidide.

24. Solid electrolyte according to any one of claims 1 to 23, wherein the ionic bifunctional molecule is present at a concentration of about 0.5% to about 50%, or about 2% to about 30%, or about 4% to about 20%, or about 5% to about 15%, by weight in the solid electrolyte.

25. Solid electrolyte according to any one of claims 1 to 24, wherein the inorganic particles comprise a material selected from glasses, glass-ceramics, ceramics, nano-ceramics and a combination of at least two of these. A solid electrolyte according to claim 25, wherein the inorganic particles comprise a ceramic, glass, or glass-ceramic based on fluoride, phosphide, sulfide, oxysulfide, or oxide. A solid electrolyte according to claim 25, wherein the inorganic particles comprise a compound of the type LISICON, thio-LISICON, argyrodite, garnet, NASICON, perovskite, oxide, sulfide, oxysulfide, phosphide, fluoride in crystalline and / or amorphous form, or a combination of at least two of these. A solid electrolyte according to claim 25, wherein the inorganic particles comprise a compound selected from the inorganic compounds of formula MLZO in which, M is an alkali metal ion, an alkaline earth metal ion, or a combination of at least two of these, and in which, when M comprises an alkaline earth metal ion, then the number of M is adjusted to achieve electroneutrality; X is chosen from F, Cl, Br, I or a combination of at least two of these; a, b, c, d, e and f are non-zero numbers and are, independently in each formula, selected to achieve electroneutrality; and v, w, x, y and z are non-zero numbers and are, independently in each formula, selected to obtain a stable compound.

29. Solid electrolyte according to claim 28, wherein M is selected from Li, Na, K, Rb, Cs, Be, Mg, Ca, Sr, Ba or a combination of at least two of these.

30. Solid electrolyte according to claim 29, wherein M is Li.

31. Solid electrolyte according to any one of claims 28 to 30, wherein the inorganic particles comprise an inorganic compound of formula MATP.

32. Solid electrolyte according to any one of claims 28 to 30, wherein the inorganic particles comprise an argyrodite-type inorganic compound of formula Li6PS5X, in which X is Cl, Br, I or a combination of at least two of these.

33. Solid electrolyte according to any one of claims 28 to 30, wherein the inorganic particles comprise an inorganic compound of formula Li6PS5Cl.

34. Solid electrolyte according to any one of claims 1 to 33, wherein the inorganic particles are present at a concentration of about 25% to about 95%, or about 40% to about 90%, or about 60% to about 90%, by weight in the solid electrolyte.

35. Solid electrolyte according to any one of claims 1 to 33, wherein the ratio "inorganic particles: ionic bifunctional molecule" by weight is in the range of 2:1 to 30:1, or 3:1 to 20:1, or 5:1 to 15:

1.

36. Solid electrolyte according to any one of claims 1 to 35, further comprising a polymer.

37. Solid electrolyte according to claim 36, wherein the polymer is a linear or branched polymer selected from polyethers, polythioethers, polyesters, polythioesters, poly(dimethylsiloxanes), alkylene polycarbonates), poly(alkylene thiocarbonate), poly(alkylenesulfones), poly(alkylenesulfones), poly(alkylenesulfones), polyimides, polyamides, polyphosphazenes, polyurethanes, poly(vinyl alcohols), polyacrylonitril, polyethacrylates and polymethacrylates, and their copolymers.

38. Solid electrolyte according to claim 37, wherein the polyether is poly(ethylene oxide) (POE), poly(propylene oxide) (POP), or a copolymer (OE / PO).

39. Solid electrolyte according to claim 37 or 38, wherein the polymer comprises crosslinked units derived from crosslinkable functional groups or their crosslinked equivalents.

40. Solid electrolyte according to claim 39, wherein the crosslinkable functional group is selected from the functional groups acrylates, methacrylates, vinyls, glycidyls and mercaptos.

41. Solid electrolyte according to claim 36, wherein the polymer is the reaction product of at least one monomer comprising at least one polymerizable or crosslinkable function and a compound comprising at least one SH functional group.

42. Solid electrolyte according to any one of claims 36 to 41, wherein the polymer is present at a concentration of about 0.1% to about 20%, or about 1% to about 15%, or about 2% to about 10%, by weight in the solid electrolyte.

43. Solid electrolyte according to any one of claims 1 to 42, further comprising an additive.

44. Solid electrolyte according to claim 43, wherein the additive is a fluorinated compound comprising an amide function.

45. Solid electrolyte according to claim 44, wherein the fluorinated compound has the formula R 6 X 6 C(O)N(H)X 7 R 7 , where R 6 and R 7 are independent of alkyl, cycloalkyl, heterocycloalkyl, aryl, or heteroaryl groups, X 6 is O, NH or absent, and X 7 is absent or is a C(O), S(O)2, or Si(R) group 8 R 9 ), where R 8and R 9 alkyl groups, and where at least one of R 6 , R 7 , R 8 and R 9 is a group substituted by one or more fluorine atom(s).

46. ​​Solid electrolyte according to claim 45, wherein R 6 is a perfluorinated group and X 6 is absent.

47. Solid electrolyte according to any one of claims 43 to 46, wherein the additive is present at a concentration of about 5% to about 40%, or about 10% to about 35%, or about 15% to about 30%, by weight in the solid electrolyte.

48. An electrochemical cell comprising a negative electrode, a positive electrode and an electrolyte, wherein the electrolyte is as defined in any one of claims 1 to 47.

49. Electrochemical cell according to claim 48, wherein the positive electrode comprises a positive electrode material comprising an electrochemically active positive electrode material.

50. Electrochemical cell according to claim 49, wherein the positive electrode material is on a current collector.

51. Electrochemical cell according to claim 49 or 50, wherein the electrochemically active positive electrode material is selected from metal phosphates, lithia metal phosphates, metal oxides, and lithia metal oxides.

52. Electrochemical cell according to claim 49 or 50, wherein the electrochemically active positive electrode material is LiM'PC t where M' is Fe, Ni, Mn, Co, or a combination of at least two of these, LiVaOs, V2O5F, UV2O5, LiM^C t, LiM”C>2, where M” is Mn, Co, Ni, or a combination of at least two of these (such as NMC, LiMn xCo y Neither z O2 with x+y+z = 1), Li(NiM'”)O2 (where M'” is Mn, Co, Al, Fe, Cr, Ti, Zr, or a combination of at least two of these), sulfur, selenium or elemental iodine, iron(III) fluoride, copper(II) fluoride, lithium iodide, carbon-based active materials such as graphite, active organic cathode materials, or a combination of at least two of these, when they are compatible with each other.

53. Electrochemical cell according to any one of claims 49 to 52, wherein the positive electrode material further comprises an electronically conductive material, a binder, a salt, an ionic bifunctional molecule, and / or inorganic particles.

54. Electrochemical cell according to any one of claims 48 to 53, wherein the negative electrode comprises a negative electrode material comprising an electrochemically active negative electrode material.

55. Electrochemical cell according to claim 54, wherein the negative electrode material is on a current collector.

56. Electrochemical cell according to claim 54 or 55, wherein the electrochemically active negative electrode material comprises a metallic film comprising an alkali or alkaline earth metal or an alloy comprising an alkali or alkaline earth metal.

57. Electrochemical cell of claim 56, wherein the alkali metal is selected from lithium and sodium.

58. Electrochemical cell according to claim 54 or 55, wherein the electrochemically active negative electrode material comprises an intermetallic compound (e.g., SnSb, TiSnSb, Cu2Sb, AlSb, FeSb2, FeSn2, and CoSn2), a metal oxide, a metal nitride, a metal phosphide, a metal phosphate (e.g., LiTi2(PC>4)3), a metal halide (e.g., a metal fluoride), a metal sulfide, a metal oxysulfide, carbon (e.g., graphite, graphene, reduced graphene oxide, hard carbon, soft carbon, exfoliated graphite, and amorphous carbon), silicon (Si), a silicon-carbon composite (Si-C), or silicon dioxide (SiO2). x ), a silicon-carbon oxide (SiOx-C) composite, tin (Sn), a tin-carbon (Sn-C) composite, tin oxide (SnOx), a tin-carbon oxide (SnO) composite x -C), and their combinations, when compatible.

59. Electrochemical cell according to claim 58, wherein the metal oxide is selected from compounds of formula M””bO c (where M”” is Ti, Mo, Mn, Ni, Co, Cu, V, Fe, Zn, Nb, or a combination thereof; and b and c are numbers such that the ratio c:b is in the range of 2 to 3) (e.g., MoO3, MoO2, M0S2, V2O5, and TiNb2O7), spinel oxides (e.g., NiCo2C>4, ZnCo2C>4, MnCo2C>4, CUCO2O4, and CoFe2O4) and LiM'””O (where M'”” is Ti, Mo, Mn, Ni, Co, Cu, V, Fe, Zn, Nb, or a combination thereof) (e.g., a lithium titanate (such as Li4Ti5O12) or a lithium molybdenum oxide (such as Li2MO4O13)).

60. Electrochemical cell according to claim 58 or 59, wherein the negative electrode material further comprises an electronically conductive material, a binder, a salt, an ionic bifunctional molecule, and / or inorganic particles.

61. A battery comprising at least one electrochemical cell as defined in any one of claims 48 to 60.

62. Battery according to claim 61, wherein said battery is selected from the group consisting of a lithium battery, a lithium-ion battery, a sodium battery, a sodium-ion battery, a potassium battery, a potassium-ion battery, a magnesium battery, and a magnesium-ion battery.

63. Battery according to claim 62, wherein said battery is a lithium battery.

64. Battery according to claim 62, wherein said battery is a lithium-ion battery.

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