Process for the preparation of a functionalized lithium salt

Abstract

The present invention relates to a process for preparing a lithium salt A comprising step a) of contacting a lithium salt B comprising at least one –S(O)2-F group with a compound C of formula (I) RO-SiR1R2R3 in the presence of a catalyst D to form a product mixture comprising said lithium salt A comprising at least one –S(O)2-OR group; said catalyst D being a compound having a pKa greater than 11 measured at 25°C. The present invention also relates to a lithium salt of formula (IIIa), (IIIb), (IIIc), (IIId), (IIIe), (IIIf), (IIIg), (IIIh), (IIIi), (IIIj), (IVa), (IVb), (IVc) or (IVd).

Description

Title of the invention: Process for preparing a functionalized lithium salt Technical field of the invention

[0001] The present invention relates to a process for preparing a lithium salt. In particular, the present invention relates to a process for preparing a lithium salt bearing functional groups. Technological background of the invention

[0002] Li-ion batteries are used as a power source in many devices such as mobile phones, computers or electric vehicles. Most current batteries contain a liquid solution of an electrolyte consisting of a lithium salt in a solvent, the latter being generally highly flammable (for example carbonate solvents). Other emerging technologies use an electrolyte in the form of a gel which limits the flammable liquid content without being risk-free. The most promising technology is based on all-solid-state batteries which do not contain flammable chemical compounds and offer a high energy density.

[0003] Many lithium salts are commercially available for this type of battery application. Examples include lithium perchlorate, lithium hexafluorophosphate, bis(trifluoromethanesulfonyl)imide and lithium bis(fluorosulfonyl)imide. Lithium sulfonyl imide salts are the most promising salts from the point of view of stability and conductivity. New lithium salts suitable for new battery technologies have been evaluated. In this respect, the use of polymer materials containing lithium sulfonyl imide salts has been considered. For example, WO 2016 / 012670 describes the preparation of conductive polymers of the polyaryl ether ketone or polyether sulfone type containing grafted lithium bis(sulfonyl)imide salts. The synthesis of this type of polymer is complex and requires numerous reaction steps, sometimes with more severe operating conditions.

[0004] There is therefore a need for the preparation of new lithium bis(sulfonyl)hnide salts following a simple procedure and resulting in good yields.

[0005] The present invention aims to resolve at least in part the drawbacks of the prior art. Summary of the invention

[0006] According to a first aspect, the present invention provides a method of preparing a lithium salt A comprising a step a) of bringing a lithium salt B comprising at least one -S(O)2-F group into contact with a compound C of formula (I) RO-SiR'R2R3 in the presence of a catalyst D to form a mixture of products comprising said lithium salt A comprising at least one -S(O)2-OR group; said catalyst D being a compound having a pKa greater than 11 measured at 25°C.

[0007] The present invention makes it possible to prepare a functionalized lithium salt in mild operating reactions with good yields and thus avoiding side reactions. In particular, the present process makes it possible to avoid the use of nucleophilic compounds such as alkoxides or amines which leads to the dissociation of the sulfonyl imide structure. The present process makes it possible to substitute the fluorine atom carried by the sulfur atom of the lithium salt B by a functional group -OR derived from the compound C. Said lithium salt A thus formed comprises a functional group -OR linked to said sulfur atom.

[0008] According to a preferred embodiment, the substituent R of said compound C comprises at least one carbon-carbon double bond. The presence of a carbon-carbon double bond will make it possible to promote the preparation of a polymer containing the lithium salt.

[0009] According to a preferred embodiment, said lithium salt B is of formula LiN(S(O)2 -F)(S(O)2R') and said lithium salt A is of formula (IV) LiN(S(O)2-OR)(S(O)2R') in which R' is a substituent selected from the group consisting of F, C1-C4 alkyl, C1-C4 perfluoroalkyl, C1-C4 alkoxy, C1-C4 perfluoroalkoxy; preferably C1-C4 alkyl, C1-C4 perfluoroalkyl, C1-C4 alkoxy, C1-C4 perfluoroalkoxy.

[0010] According to a preferred embodiment, said lithium salt B comprises two -S(O)2-F groups to form a lithium salt A comprising two -S(O)2-OR groups. Thus, said lithium salt A comprises two -OR groups each comprising at least one carbon-carbon double bond allowing the facilitated formation of a polymer containing a lithium salt.

[0011] According to a preferred embodiment, said lithium salt B is Li-N(S(O)2-F)2 and said lithium salt A is of formula (III) Li-N(S(O)2-OR)2.

[0012] According to a preferred embodiment, said compound C is of formula (I) RO-SiR'R2 R3 in which the groups R1, R2 and R3 are independently of each other selected from the group consisting of H and Ci-Cio alkyl.

[0013] According to a preferred embodiment, said compound C is of formula (I) RO-SiR'R2 R3 in which the group R is of formula R4-X-(Y)n- in which R4 is a radical comprising at least one carbon-carbon double bond; X is a heteroatom selected from the group consisting of O, S and N(R5) in which R5 is H or Ci-Cio alkyl; Y is a group selected from the group consisting of -C(R6)(R7)-, -C(R6)(R7)C(R6)(R7)SC(R6)(R7)- and -[(O)z(C(R8)(R9)-C(R8)(R9)O)mC(R8)(R9) [C(R8)(R9)]- with R6 and R7 independently selected for each carbon atom and for each Y unit from H or F, R8 and R9 independently selected for each carbon atom and for each Y unit from H, F or CH3, m an integer from 1 to 50, z = 0 if X is O; n is an integer from 1 to 50.

[0014] According to a preferred embodiment, the group R4 is of formula (Ia), (Ib), (Ic) or (Id): {fa) (Ib) ' 7 (ld)

[0016] in which

[0017] A, B and V are independently of each other selected from the group consisting of H, F, Cl, Br, I, C1-C10 alkyl optionally substituted by one or more substituent(s) R”, C2-C10 alkenyl optionally substituted by one or more substituent(s) R”, C3-C10 cycloalkyl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups, C4-C10 cycloalkenyl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups, C6-C12 aryl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups;

[0018] W is selected from O and S

[0019] R” is selected from the group consisting of F, Cl, I, Br, C1-C4 ether, C1-C4 ester, C1-C4 thioether, C1-C4 thioester.

[0020] According to a preferred embodiment, said catalyst D is selected from the group consisting of N,N-Diisopropylethylamine, l,8-Diazabicyclo(5.4.0)undec-7-ene, 6-(Dibutylamino)-l,8-diazabicyclo[5.4.0]undec-7-ene, l,8-Diazabicyclo[5.4.0]undec-7-ene bound to polystyrene, l,5,7-Triazabicyclo[4.4.0]dec-5-ene, 7-Methyl-l,5,7-triazabicyclo[4.4.0]dec-5-ene, 1,1,3,3-Tetramethylguanidine, 2-tert-Butyl-1,1,3,3-tetramethylguanidine, l,5,7-Triazabicyclo[4.4.0]dec-5-ene bound to polystyrene, polystyrene, 1,4-Diazabicyclo[2.2.2]octane, Quinuclidine, 1,5-Diazabicyclo(4.3.0)non-5-ene, 2,6-Di-tert-butylpyridine, 2,8,9-Trimethyl-2,5,8,9-tetraza-l-phosphabicyclo[3.3.3]undecane, Cyclodi-phosphazane, Lithium diisopropylamide, sodium diisopropylamide, potassium diiso-propylamide, magnesium diisopropylamide, calcium diisopropylamide, rubidium diisopropylamide, lithium bis(trimethylsilyl)amide, sodium bis(trimethylsilyl)amide, potassium bis(trimethylsilyl)amide, magnesium bis(trimethylsilyl)amide, calcium bis(trimethylsilyl)amide, rubidium bis(trimethylsilyl)amide, lithium tetramethylpi-peridide, sodium tetramethylpiperidide, potassium tetramethylpiperidide, magnesium tetramethylpiperidide, calcium tetramethylpiperidide, rubidium tetramethylpiperidide, [18-crown-6]-KHF2, KHF2, N,N'-diisopropylimidazonium, bifluoride, tetrabuty-lammonium.

[0021] According to a preferred embodiment, said method also comprises a step b) of purification of said lithium salt A; said step b) comprising the extraction of said lithium salt A with a non-polar organic solvent.

[0022] According to a preferred embodiment, step a) is carried out at a temperature of 10 to 50°C.

[0023] According to a second aspect, the present invention provides a lithium salt of formula (Ilia), (Illb), (IHc), (Iïïd), (me), (Illf), (Illg), (Illh), (Illi), (Illj), (IVa), (IVb), (IVc) or (IVd) o h Aï A H / OX —A y / S AiHÛ x OO h he MÀ) Q -S— N -- S —O - AA 1 HO i | . on O X-\ f Y / X A ¥ (¾) y OO v. H Ü Æ 'C 5"™-Sï ,;W xmp •Y oo \ . h ii ïï(A) <i™S-'™X™S™<)--XA) M H e il V # ono AV ■Jili YOO < "He

[0024] wherein the substituents A, B, V and W are as defined above according to the present invention; the substituents X, Y are as defined above according to the present invention; and n is as defined above according to the present invention and R' is as defined above according to the present invention. According to a preferred embodiment, said lithium salt is of formula (Ilia), (Illb), (inc), (ind), (me), (IHf), (nig), (nih), (Hli), (Hlj), (IVa), (IVb), (IVc) or (IVd) in which

[0026] A and B are identical and are selected from the group consisting of H, F, Cl, Br and I;

[0027] V is selected from the group consisting of H, F, Cl, Br, I, C1-C10 alkyl optionally substituted by one or more substituent(s) R”, C2-C10 alkenyl optionally substituted by one or more substituent(s) R”, C3-C10 cycloalkyl optionally substituted by one or more substituent(s) R' ' or one or more C1-C5 alkyl groups, C4-C10 cycloalkenyl optionally substituted by one or more several substituent(s) R” or one or more C1-C5 alkyl groups, C6-Ci2 aryl optionally substituted by one or more substituent(s) R' ' or one or more C1-C5 alkyl groups with R” is selected from the group consisting of F, Cl, I, Br, C1-C4 ether, C1-C4 ester, C1-C4 thioether, C1-C4 thioester; preferably V is selected from the group consisting of H, F, Cl, Br, I, C1-C5 alkyl C1-C5 perfluoroalkyl, C6R106 with R10 independently selected from H, F, C1-C5 alkyl;

[0028] W is O;

[0029] X is O;

[0030] Y is a group selected from the group consisting of CH2CH2, CH2CF2, CF 2CF2, CH2CHF, CF2CH2, CHFCH2, and n is an integer from 1 to 25; or

[0031] Y is a group -[(C(R8)(R9)-C(R8)(R9)O)mC(R8)(R9)C(R8)(R9)]- with R8 and R9 independently selected for each carbon atom and for each Y unit from H, F or CH3, m is an integer from 1 to 25 and n is 1;

[0032] R' is a substituent selected from the group consisting of F, C1-C4 alkyl, C1-C4 perfluoroalkyl, C1-C4 alkoxy, C1-C4 perfluoroalkoxy; preferably C1-C4 alkyl, C1-C4 perfluoroalkyl, C1-C4 alkoxy, C1-C4 perfluoroalkoxy.

[0033] According to a preferred embodiment, said lithium salt is of formula (Ilia), (Illb), (inc), (ind), (me), (inf), (nig), (nih), (nii), (nij), (IVa), (IVb), (IVc) or (IVd) in which A and B are H, V is CH3, W is O, X is O and Y is a group selected from the group consisting of CH2CH2, CH2CF2, CF2CF2, CH2CHF, CF2CH2, CHFCH2, and n is an integer from 1 to 10; or

[0034] Y is a group -[(C(R8)(R9)-C(R8)(R9)O)mC(R8)(R9)C(R8)(R9)]- with R8 and R9 independently selected for each carbon atom and for each Y unit from H, F or CH3, m is an integer from 1 to 25 and n is 1;

[0035] R' is a substituent selected from the group consisting of F, C1-C4 alkyl, C1-C4 perfluoroalkyl, C1-C4 alkoxy, C1-C4 perfluoroalkoxy; preferably C1-C4 alkyl, C1-C4 perfluoroalkyl, C1-C4 alkoxy, C1-C4 perfluoroalkoxy.

[0036] According to a preferred embodiment, said lithium salt is of formula (IIIa) in which A and B are H, V is CH3, W is O, X is O and Y is a group selected from the group consisting of CH2CH2, CH2CF2, CF2CF2, CH2CHF, CF2CH2, CHFCH2, and n is an integer from 1 to 10; or

[0037] Y is a group -[(C(R8)(R9)-C(R8)(R9)O)mC(R8)(R9)C(R8)(R9)]- with R8 and R9 independently selected for each carbon atom and for each Y unit from H, F or CH3, m is an integer from 1 to 25 and n is 1. Detailed description of the invention

[0038] According to a first aspect of the invention, a method for preparing a lithium salt A is provided. Said method comprises a step of contacting a lithium salt B comprising at least one -S(O)2-F group with a compound C of formula (I) RO-SiR1 R2R3. Said lithium salt A is formed by an exchange reaction between the fluorine atom carried by the -S(O)2- group of said lithium salt B and the -OR group derived from compound C and carried by the silicon atom thereof. Said lithium salt A thus formed comprises at least one -S(O)2-OR group. Said process according to the present invention also results in the formation of a co-product F-SiR'R2R3. The present process avoids the formation of HF (the fluorine atom bonding to the Si atom) during the reaction which would have required the neutralization thereof by an excess of base or additional purification steps. The present invention makes it possible to prepare a functionalized lithium salt in mild operating reactions with good yields and thus avoiding side reactions. Compound B

[0039] As mentioned above, said lithium salt B comprises at least one -S(O)2-F group. According to a preferred embodiment, said lithium salt B is of formula LiN(S(O)2-F)(S(O)2R') in which R' is a substituent selected from the group consisting of F, C1-C4 alkyl, C1-C4 perfluoroalkyl, CrC4 alkoxy, Ci-C4 perfluoroalkoxy; preferably CrC4 alkyl, CrC4 perfluoroalkyl, CrC4 alkoxy, CrC4 perfluoroalkoxy. Thus, preferably, the present process comprises a step of contacting LiN(S(O)2-F)(S(O)2R') with a compound C of formula (I) RO-SiR'R2R3 as defined in the present application, preferably in the presence of catalyst D as defined in the present application.

[0040] Preferably, said lithium salt B comprises two -S(O)2-F groups.

[0041] In particular, said lithium salt B is Li-N(S(O)2-F)2, i.e. lithium bis(sulfonyl)hnide also called LiFSI. Thus, preferably, the present process comprises a step of bringing Li-N(S(O)2-F)2 into contact with a compound C of formula (I) RO-SiR'R2R3 as defined in the present application, preferably in the presence of catalyst D as defined in the present application. Compound C

[0042] According to a preferred embodiment, said compound C is of formula (I) RO-SiR'R2 R3.

[0043] According to a preferred embodiment, said compound C is of formula (I) RO-SiR'R2 R3 in which the groups R1, R2 and R3 are independently of each other selected from the group consisting of H, C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl. Preferably, the groups R1, R2 and R3 are independently of each other selected from the group consisting of H, C1-C15 alkyl, C3-C15 cycloalkyl, C6-C15 aryl. More preferably, the groups R1, R2 and R3 are independently of each other selected from the group consisting of H, C1-C10

[0044]

[0045]

[0046]

[0047]

[0048]

[0049]

[0050]

[0051]

[0052]

[0053]

[0054] alkyl, C3-Ci0 cycloalkyl, C6-Ci2 aryl. In particular, the groups R1, R2 and R3 are independently of each other selected from the group consisting of H and Ci-Cio alkyl. More particularly, the groups R1, R2 and R3 are independently of each other selected from the group consisting of H, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, sec-butyl, pentyl. Preferably, the groups R1, R2 and R3 are independently of each other selected from the group consisting of H, methyl, ethyl, propyl, tert-butyl. Preferably, the groups R1 and R2 are identical and are selected from the group consisting of H, methyl, ethyl and the group R3 is selected from the group consisting of H, methyl, ethyl, propyl, tert-butyl.In a particularly preferred manner, the groups R1, R2 and R3 are identical and are selected from the group consisting of H, methyl, ethyl. According to a preferred embodiment, the substituent R of said compound C comprises at least one carbon-carbon double bond. As mentioned above, the presence of a carbon-carbon double bond will make it possible to promote the preparation of a polymer containing the lithium salt. Preferably, the group R of said compound C is of formula R4-X-(Y)n- in which R4 is a radical comprising at least one carbon-carbon double bond; X is a heteroatom selected from the group consisting of O, S and N(R5) wherein R5 is H or C1-C10 alkyl; preferably R5 is H, CH3 or C2H5; Y is a group selected from the group consisting of -C(R6)(R7)-, -C(R6)(R7)C(R6)(R7)SC(R6)(R7)- and -[(O)z(C(R8)(R9)-C(R8)(R9)O)mC(R8)(R9)C(R8)(R9)]- with R6 and R7 independently selected for each carbon atom and for each Y unit from H or F; R8 and R9 independently selected for each carbon atom and for each Y unit from H, F or CH3, m an integer from 1 to 50, advantageously from 1 to 40, preferably from 1 to 30, more preferably from 1 to 20, in particular from 1 to 10. z = 0 if X is O; n is an integer from 1 to 50, advantageously from 1 to 40, preferably from 1 to 30, more preferably from 1 to 20, in particular from 1 to 10. According to a preferred embodiment, in said compound C, the group R4 is of formula (Ia), (Ib), (Ic) or (Id): 0a) U b) (Id)

[0055] in which

[0056] A, B and V are independently of each other selected from the group consisting of H, F, Cl, Br, I, C1-C2o alkyl optionally substituted by one or more substituent(s) R”, C2-C2o alkenyl optionally substituted by one or more substituent(s) R”, C3-C20 cycloalkyl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups, C4-C20 cy-cloalkenyl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups, C6-C20 aryl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups;

[0057] W is selected from O and S, preferably O;

[0058] R” is selected from the group consisting of F, Cl, I, Br, Ci-C4 ether, CrC4 ester, CrC4 thioether, CrC4 thioester, preferably F, CrC4 ether, CrC4 ester, CrC4 thioether, CrC4 thioester.

[0059] Preferably, in said compound C, the group R4 is of formula (Ia), (Ib), (Ic) or (Id) as illustrated above in which A, B and V are independently of each other selected from the group consisting of H, F, Cl, Br, I, C1-C15 alkyl optionally substituted by one or more substituent(s) R”, C2-C15 alkenyl optionally substituted by one or more substituent(s) R”, C3-C15 cycloalkyl optionally substituted by one or more substituent(s) R' ' or one or more C1-C5 alkyl groups, C4-C15 cycloalkenyl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups, C6-C15 aryl optionally substituted by one or more substituent(s) R' ' or one or more C1-C5 alkyl groups;

[0060] W is selected from O and S, preferably O;

[0061] R” is selected from the group consisting of F, Cl, I, Br, CrC4 ether, CrC4 ester, CrC4 thioether, CrC4 thioester, preferably F, CrC4 ether, CrC4 ester, CrC4 thioether, CrC4 thioester.

[0062] More preferably, in said compound C, the group R4 is of formula (Ia), (Ib), (Ic) or (Id) as illustrated above in which A, B and V are independently of one another selected from the group consisting of H, F, Cl, Br, I, C1-C10 alkyl optionally substituted by one or more substituent(s) R”, C2-C10 alkenyl optionally substituted by one or more substituent(s) R”, C3-C10 cycloalkyl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups, C4-C10 cycloalkenyl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups, C6 -C10 aryl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups;

[0063] W is selected from O and S, preferably O;

[0064] R” is selected from the group consisting of F, Cl, I, Br, C1-C4 ether, C1-C4 ester, CrC4 thioether, CrC4 thioester, preferably F, CrC4 ether, CrC4 ester, CrC4 thioether, CrC4 thioester.

[0065] In particular, in said compound C, the group R4 is of formula (Ia), (Ib), (Ic) or (Id) as illustrated above in which A, B and V are independently of each other selected from the group consisting of H, F, Cl, Br, I, C1-C10 alkyl, C2-C10 alkenyl, C3-C10 cycloalkyl, C4-C10 cycloalkenyl, C6-C10 aryl, C1-C10 perfluoroalkyl, C2-C10 perfluoroalkenyl, C3-C10 perfluorocycloalkyl, C4-C10 perfluorocycloalkenyl, C6R105 with R10 independently selected from H, F, C1-C5 alkyl;

[0066] W is selected from O and S, preferably O.

[0067] More particularly, in said compound C, the group R4 is of formula (Ia), (Ib), (Ic) or (Id) as illustrated above in which A, B and V are independently of each other selected from the group consisting of H, F, Cl, Br, I, C1-C5 alkyl, C1-C5 perfluoroalkyl, C6R105 with R10 independently selected from H, F, C1-C5 alkyl;

[0068] W is selected from O and S, preferably O.

[0069] Preferably, in said compound C, the group R4 is of formula (Ia), (Ib), (Ic) or (Id) as illustrated above in which A and B are independently of each other selected from the group consisting of H, F, Cl, I, Br, CH3, C2H5, CF3, C2F5, phenyl; and V is selected from the group consisting of H, F, Cl, Br, I, C1-C5 alkyl, C1-C5 perfluoroalkyl, C6R105 with R10 independently selected from H, F, C1-C5 alkyl;

[0070] W is selected from O and S, preferably O.

[0071] Preferably, the R4 group is of formula (Ia), (Ib), (Ic) or (Id) as illustrated above in which

[0072] A and B are the same and are selected from the group consisting of H, F, Cl, I, Br; or

[0073] A is H and B is selected from the group consisting of F, Cl, Br, I, CH3, C2H5, CF 3, C2F5, phenyl.

[0074] V is selected from the group consisting of H, F, Cl, Br, I, C1-C5 alkyl, C1-C5 perfluoroalkyl, C6R105 with R10 independently selected from H, F, C1-C5 alkyl;

[0075] W is selected from O and S, preferably O.

[0076] Thus, according to the present invention, said compound C may be of formula (Ia), (Ib), (Ic) or (Id) (kl)

[0077] in which the substituents A, B, V, W, X, Y, R1, R2 and R3 are as defined above in the present application according to any one of the embodiments described.

[0078] According to a preferred embodiment, said compound C may be of formula (Ia), (Ib), (Ic) or (Id) AV W / R* / \ i . B — X— (Y teO— Si- R" Y s w iV (there)

[0079] in which

[0080] R1, R2 and R3 are independently of each other selected from the group consisting of H, C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl; advantageously R1, R2 and R3 are independently of each other selected from the group consisting of H, C1-C15 alkyl, C3-C15 cycloalkyl, C6-C15 aryl; preferably R1, R2 and R3 are independently of each other selected from the group consisting of H, C1-C10 alkyl, C3-C10 cycloalkyl, C6-C12 aryl; more preferably R1, R2 and R3 are independently of each other selected from the group consisting of H and C1-C10 alkyl; in particular R1, R2 and R3 are independently of each other selected from the group consisting of H, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, sec-butyl, pentyl; more particularly R1, R2 and R3 are independently of each other selected from the group consisting of H, methyl, ethyl, propyl, tert-butyl;

[0081] X is a heteroatom selected from the group consisting of O, S and N(R5) wherein R5 is H or C1-C10 alkyl;

[0082] Y is a group selected from the group consisting of -C(R6)(R7)-, -C(R6)(R 7)C(R6)(R7)SC(R6)(R7)- and -[(O)z(C(R8)(R9)-C(R8)(R9)O)mC(R8)(R9)C(R8)(R9)]- with R6 and R7 independently selected for each carbon atom and for each Y unit from H or F; R8 and R9 independently selected for each carbon atom and for each Y unit from H, F or CH3;

[0083] m an integer from 1 to 50, advantageously from 1 to 40, preferably from 1 to 30, more preferably from 1 to 20, in particular from 1 to 10;

[0084] z = 0 if X is O;

[0085] n is an integer from 1 to 50, advantageously from 1 to 40, preferably from 1 to 30, more preferably from 1 to 20, in particular from 1 to 10;

[0086] A, B and V are independently of each other selected from the group consisting of H, F, Cl, Br, I, C1-C2O alkyl optionally substituted by one or more substituent(s) R”, C2-C2O alkenyl optionally substituted by one or more substituent(s) R”, C3-C2O cycloalkyl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups, C4-C2O cycloalkenyl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups, C6-C2O aryl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups with R” selected from the group consisting of F, Cl, I, Br, C1-C4 ether, CrC4 ester, CrC4 thioether, Ci-C4 thioester, preferably F, Ci-C4 ether, Ci-C4 ester, Ci-C4 thioether, Ci -C4 thioester;advantageously A, B and V are independently of each other selected from the group consisting of H, F, Cl, Br, I, C1-C15 alkyl optionally substituted by one or more substituent(s) R”, C2-C15 alkenyl optionally substituted by one or more substituent(s) R”, C3-C15 cycloalkyl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups, C4-C15 cycloalkenyl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups, C6-C15 aryl optionally substituted by one or more substituent(s) R' ' or one or more C1-C5 alkyl groups with R” selected from the group consisting of F, Cl, I, Br, CrC4 ether, CrC4 ester, CrC4 thioether, CrC4 thioester, preferably F, CrC4 ether, CrC4 ester, CrC4 thioether, CrC4 thioester;preferably A, B and V are independently of each other selected from the group consisting of H, F, Cl, Br, I, C1-C10 alkyl optionally substituted by one or more substituent(s) R”, C2-C10 alkenyl optionally substituted by one or more substituent(s) R”, C3-C10 cycloalkyl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups, C4-C10 cycloalkenyl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups, C6 -C10 aryl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups with R” selected from the group consisting of F, Cl, I, Br, C1-C4 ether, C1-C4 ester, CrC4 thioether, Ci-C4 thioester, preferably F, CrC4 ether, Ci-C4 ester, Ci-C4 thioether, CrC4 thioester;more preferably A, B and V are independently of each other selected from the group consisting of H, F, Cl, Br, I, C1-C10 alkyl, C2-C10 alkenyl, C3-C10 cycloalkyl, C4-C10 cy-; cloalkenyl, C6-Ci0 aryl, C1-Ci0 perfluoroalkyl, C2-Ci0 perfluoroalkenyl, C3-Ci0 per-fluorocycloalkyl, C4-C10 perfluorocycloalkenyl, C6-Ci0 perfluoroaryl; in particular A, B and V are independently of each other selected from the group consisting of H, F, Cl, Br, I, C1-C5 alkyl, C1-C5 perfluoroalkyl, C6R105 with R10 independently selected from H, F, C1-C5 alkyl;

[0087] W is selected from O and S, preferably O.

[0088] According to a particular embodiment, said compound C may be of formula (Ia), (Ib), (Ic) or (Id) ay B (Y)nO— SH R* / / s; (lay (YO— If— R' BX—(Y )»CH- Si— R (fc) AV R' y \ I B Hizrv / A ■ i

[0089] in which

[0090] R1 and R2 are the same and are selected from the group consisting of H, methyl, ethyl and R3 is selected from the group consisting of H, methyl, ethyl, propyl, tert-butyl; preferably, R1, R2 and R3 are the same and are selected from the group consisting of H, methyl, ethyl;

[0091] X is a heteroatom selected from the group consisting of O, S and N(R5) wherein R5 is H or C1-C10 alkyl; preferably R5 is H, CH3 or C2H5;

[0092] Y is a group selected from the group consisting of -C(R6)(R7)-, -C(R6)(R 7)C(R6)(R7)SC(R6)(R7)- and -[(O)z(C(R8)(R9)-C(R8)(R9)O)mC(R8)(R9)C(R8)(R9)]- with R6 and R7 independently selected for each carbon atom and for each Y unit from H or F; R8 and R9 independently selected for each carbon atom and for each Y unit from H, F or CH3;

[0093] m an integer from 1 to 50, advantageously from 1 to 40, preferably from 1 to 30, more preferably from 1 to 20, in particular from 1 to 10;

[0094] z = 0 if X is O;

[0095] n is an integer from 1 to 50, advantageously from 1 to 40, preferably from 1 to 30, more preferably from 1 to 20, in particular from 1 to 10;

[0096] A and B are independently of each other selected from the group consisting of H, F, Cl, I, Br, CH3, C2H5, CF3, C2F5, phenyl; preferably A and B are the same and are selected from the group consisting of H, F, Cl, I, Br or A is H and B is selected from the group consisting of F, Cl, Br, I, CH3, C2H5, CF3, C2F5, phenyl;

[0097] V is selected from the group consisting of H, F, Cl, Br, I, C1-C5 alkyl, C1-C5 perfluoroalkyl, C6R105 with R10 independently selected from H, F, C1-C5 alkyl;

[0098] W is selected from O and S, preferably O. Compound A

[0099] As mentioned above, said lithium salt A is formed by an exchange reaction between the fluorine atom of the S(O)2F group carried by said lithium salt B and said -OR group derived from said compound C of formula (I) RO-SiR'R2R3.

[0100] According to a preferred embodiment, said lithium salt A comprises at least one -S(O)2-OR group. Preferably, said lithium salt A comprises two -S(O)2-OR groups when said lithium salt B comprises two -S(O)2-F groups. Thus, said lithium salt A comprises two -OR groups each comprising at least one carbon-carbon double bond allowing the facilitated formation of a polymer containing a lithium salt.

[0101] According to a particular embodiment, said lithium salt A is of formula (III) Li-N(S(O)2-OR)2 with R of formula R4-X-(Y)n- in which R4 is a radical comprising at least one carbon-carbon double bond; X is a heteroatom selected from the group consisting of O, S and N(R5) in which R5 is H or Ci-Cio alkyl; preferably R5 is H, CH3 or C2H5; Y is a group selected from the group consisting of -C(R6)(R7)-, -C(R6)(R7)C(R6)(R7)SC(R6)(R7)- and -[(O)Z(C(R8)(R9)-C(R8)(R 9)O)mC(R8)(R9)C(R8)(R9)]- with R6 and R7 independently selected for each carbon atom and for each unit Y from H or F; R8 and R9 independently selected for each carbon atom and for each Y unit from H, F or CH3; m an integer from 1 to 50, advantageously from 1 to 40, preferably from 1 to 30, more preferably from 1 to 20, in particular from 1 to 10; z = 0 if X is O; n is an integer from 1 to 50, advantageously from 1 to 40, preferably from 1 to 30, more preferably from 1 to 20, in particular from 1 to 10.

[0102] When said lithium salt A is of formula (III) Li-N(S(O)2-OR)2, the substituents R are selected independently of one another for each of the S(O)2-OR functional groups.

[0103] Thus, according to a preferred embodiment, said lithium salt A is of formula (Illa), (Illb), (IIIc), (ind), (me), (Illf), (Illg), (Illh), (Illi) or (Illj): AV * "X™ VO ' Q / / ' \ | | S» 15 W (Yk-O—S~ X—S—O-(¥)u OSX (ÏHf} AV y^sY "yx p $ W ( YVO—S■— N —■ S— O (Y)ft lî H ' v OO x" (Wi AV W ,e 1 / -XO 0 Hey ( y VO— S— N—S— O ( Y in H » \, OG Gllhi O—S—NS—DYTm BH% QO UIG 3

[0104] in which

[0105] X is a heteroatom selected from the group consisting of O, S and N(R5) wherein R5 is H or Ci-Cio alkyl;

[0106] Y is a group selected from the group consisting of -C(R6)(R7)-, -C(R6)(R 7)C(R6)(R7)SC(R6)(R7)- and -[(O)z(C(R8)(R9)-C(R8)(R9)O)mC(R8)(R9)C(R8)(R9)]- with R6 and R7 independently selected for each carbon atom and for each Y unit from H or F; R8 and R9 independently selected for each carbon atom and for each Y unit from H, F or CH3;

[0107] m an integer from 1 to 50, advantageously from 1 to 40, preferably from 1 to 30, more preferably from 1 to 20, in particular from 1 to 10;

[0108] z = 0ifXisO;

[0109] n is an integer from 1 to 50, advantageously from 1 to 40, preferably from 1 to 30, more preferably from 1 to 20, in particular from 1 to 10;

[0110] A, B and V are independently of each other selected from the group consisting of H, F, Cl, Br, I, C1-C2O alkyl optionally substituted by one or more substituent(s) R”, C2-C2O alkenyl optionally substituted by one or more substituent(s) R”, C3-C2O cycloalkyl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups, C4-C2O cycloalkenyl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups, C6-C2O aryl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups with R” selected from the group consisting of F, Cl, I, Br, C1-C4 ether, CrC4 ester, CrC4 thioether, CrC4 thioester, preferably F, CrC4 ether, CrC4 ester, CrC4 thioether, Ci -C4 thioester;advantageously A, B and V are independently of each other selected from the group consisting of H, F, Cl, Br, I, C1-C15 alkyl optionally substituted by one or more substituent(s) R”, C2-C15 alkenyl optionally substituted by one or more substituent(s) R”, C3-C15 cycloalkyl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups, C4-C15 cycloalkenyl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups, C6-C15 aryl optionally substituted by one or more substituent(s) R' ' or one or more C1-C5 alkyl groups with R” selected from the group consisting of F, Cl, I, Br, CrC4 ether, CrC4 ester, CrC4 thioether, CrC4 thioester, preferably F, CrC4 ether, CrC4 ester, CrC4 thioether, CrC4 thioester;preferably A, B and V are independently of each other selected from the group consisting of H, F, Cl, Br, I, C1-C10 alkyl optionally substituted by one or more substituent(s) R”, C2-C10 alkenyl optionally substituted by one or more substituent(s) R”, C3-C10 cycloalkyl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups, C4-C10 cycloalkenyl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups, C6-C10 aryl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups with R” selected from the group consisting of F, Cl, I, Br, CrC4 ether, CrC4 ester, CrC4 thioether, CrC4 thioester, preferably F, CrC4 ether, CrC4 ester, CrC4 thioether, CrC4 thioester;more preferably A, B and V are independently of each other selected from the group consisting of H, F, Cl, Br, I, C1-C10 alkyl, C2-C10 alkenyl, C3-C10 cycloalkyl, C4-C10 cycloalkenyl, C6-C10 aryl, C1-C10 perfluoroalkyl, C2-C10 perfluoroalkenyl, C3-C10 per-fluorocycloalkyl, C4-C10 perfluorocycloalkenyl, C6-C10 perfluoroaryl; in particular A, B and V are independently of each other selected from the group; consisting of H, F, Cl, Br, I, C1-C5 alkyl, C1-C5 perfluoroalkyl, C6R105 with R10 independently selected from H, F, C1-C5 alkyl;

[0111] W is selected from O and S, preferably O.

[0112] Preferably, said lithium salt A is of formula (Illa), (Illb), (IIIc), (Illd), (Ille), (Illf), (nig), (nih), (Hli) or (Illj) in which

[0113] X is a heteroatom selected from the group consisting of O, S and N(R5) wherein R5 is H or C1-C10 alkyl; preferably R5 is H, CH3 or C2H5;

[0114] Y is a group selected from the group consisting of -C(R6)(R7)-, -C(R6)(R 7)C(R6)(R7)SC(R6)(R7)- and -[(O)z(C(R8)(R9)-C(R8)(R9)O)mC(R8)(R9)C(R8)(R9)]- with R6 and R7 independently selected for each carbon atom and for each Y unit from H or F; R8 and R9 independently selected for each carbon atom and for each Y unit from H, F or CH3;

[0115] m an integer from 1 to 50, advantageously from 1 to 40, preferably from 1 to 30, more preferably from 1 to 20, in particular from 1 to 10;

[0116] z = 0ifXisO;

[0117] n is an integer from 1 to 50, advantageously from 1 to 40, preferably from 1 to 30, more preferably from 1 to 20, in particular from 1 to 10;

[0118] A and B are independently of each other selected from the group consisting of H, F, Cl, I, Br, CH3, C2H5, CF3, C2F5, phenyl; preferably A and B are the same and are selected from the group consisting of H, F, Cl, I, Br or A is H and B is selected from the group consisting of F, Cl, Br, I, CH3, C2H5, CF3, C2F5, phenyl;

[0119] V is selected from the group consisting of H, F, Cl, Br, I, C1-C5 alkyl, C1-C5 perfluoroalkyl, C6R105 with R10 independently selected from H, F, C1-C5 alkyl;

[0120] W is selected from O and S, preferably O.

[0121] In particular, said lithium salt A is of formula (Ilia), (Illb), (IIIc) or (Illd) as defined above.

[0122] Alternatively, said lithium salt A is of formula (IV) LiN(S(O)2-OR)(S(O)2R') when said lithium salt B is of formula LiN(S(O)2-F)(S(O)2R'). Said lithium salt A is of formula (IV) LiN(S(O)2-OR)(S(O)2R') in which R' is a substituent selected from the group consisting of F, C1-C4 alkyl, C1-C4 perfluoroalkyl, C1-C4 alkoxy, C1-C4 perfluoroalkoxy and R is as defined above in the present application.

[0123] Thus, said lithium salt A is of formula (IV) LiN(S(O)2-OR)(S(O)2R') in which

[0124] R' is a substituent selected from the group consisting of F, C1-C4 alkyl, C1-C4 perfluoroalkyl, C1-C4 alkoxy, C1-C4 perfluoroalkoxy; preferably C1-C4 alkyl, C1- C4 perfluoroalkyl, C1-C4 alkoxy, CrC4 perfluoroalkoxy;

[0125] R is of formula R4-X-(Y)n- in which R4 is a radical comprising at least one carbon-carbon double bond; X is a heteroatom selected from the group consisting of O, S and N(R5) in which R5 is H or Ci-Cio alkyl; preferably R5 is H, CH3 or C2H5; Y is a group selected from the group consisting of -C(R6)(R7)-, -C(R6)(R7)C(R6)(R7)SC(R6)(R7)- and -[(O)z(C(R8)(R9)-C(R8)(R9)O)mC(R8)(R9 )C(R8)(R9)]- with R6 and R7 independently selected for each atom of carbon and for each unit Y among H or F; R8 and R9 independently selected for each carbon atom and for each Y unit among H, F or CH3; m an integer from 1 to 50, advantageously from 1 to 40, preferably from 1 to 30, more preferably from 1 to 20, in particular from 1 to 10; z = 0 if X is O; n is an integer from 1 to 50, advantageously from 1 to 40, preferably from 1 to 30, more preferably from 1 to 20, especially from 1 to 10

[0126] Thus, said lithium salt A is of formula (IVa), (IVb), (IVc) or (IVd) (IVd)

[0127] in which

[0128] X is a heteroatom selected from the group consisting of O, S and N(R5) wherein R5 is H or Ci-Cio alkyl;

[0129] Y is a group selected from the group consisting of -C(R6)(R7)-, -C(R6)(R 7)C(R6)(R7)SC(R6)(R7)- and -[(O)z(C(R8)(R9)-C(R8)(R9)O)mC(R8)(R9)C(R8)(R9)]- with R6 and R7 independently selected for each carbon atom and for each Y unit from H or F; R8 and R9 independently selected for each carbon atom and for each Y unit from H, F or CH3;

[0130] m an integer from 1 to 50, advantageously from 1 to 40, preferably from 1 to 30, more preferably from 1 to 20, in particular from 1 to 10;

[0131] z = 0ifXisO;

[0132] n is an integer from 1 to 50, advantageously from 1 to 40, preferably from 1 to 30, more preferably from 1 to 20, in particular from 1 to 10;

[0133] A, B and V are independently of each other selected from the group consisting of H, F, Cl, Br, I, C1-C2O alkyl optionally substituted by one or more substituent(s) R”, C2-C2O alkenyl optionally substituted by one or more substituent(s) R”, C3-C2O cycloalkyl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups, C4-C2O cycloalkenyl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups, C6-C2O aryl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups with R” selected from the group consisting of F, Cl, I, Br, C1-C4 ether, CrC4 ester, CrC4 thioether, CrC4 thioester, preferably F, CrC4 ether, CrC4 ester, CrC4 thioether, Ci -C4 thioester;advantageously A, B and V are independently of one another selected from the group consisting of H, F, Cl, Br, I, C1-C15 alkyl optionally substituted by one or more substituent(s) R”, C2-C15 alkenyl optionally substituted by one or more substituent(s) R”, C3-C15 cycloalkyl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups, C4-C15 cycloalkenyl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups, C6-C15 aryl optionally substituted by one or more substituent(s) R' ' or one or more C1-C5 alkyl groups with R” selected from the group consisting of F, Cl, I, Br, CrC4 ether, CrC4 ester, CrC4 thioether, CrC4 thioester, preferably F, CrC4 ether, Ci-C4 ester, CrC4 thioether, CrC4 thioester;preferably A, B and V are independently of each other selected from the group consisting of H, F, Cl, Br, I, Ci-Cio alkyl optionally substituted by one or more substituent(s) R”, C2-Ci0 alkenyl optionally substituted by one or more substituent(s) R”, C3-Ci0 cycloalkyl optionally substituted by one or more substituent(s) R” or one or ; several C1-C5 alkyl groups, C4-C10 cycloalkenyl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups, C6 -C10 aryl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups with R” selected from the group consisting of F, Cl, I, Br, C1-C4 ether, C1-C4 ester, C1-C4 thioether, C1-C4 thioester, preferably F, C1-C4 ether, C1-C4 ester, C1-C4 thioether, C1-C4 thioester; more preferably A, B and V are independently of each other selected from the group consisting of H, F, Cl, Br, I, CrC10 alkyl, C2-C10 alkenyl, C3-Ci0 cycloalkyl, C4-C10 cycloalkenyl, C6-Cio aryl, CrCio perfluoroalkyl, C2-Ci0 perfluoroalkenyl, C3-Ci0 per-fluorocycloalkyl, C4-C10 perfluorocycloalkenyl, C6-Ci0 perfluoroaryl;in particular A, B and V are independently of each other selected from the group consisting of H, F, Cl, Br, I, C1-C5 alkyl, C1-C5 perfluoroalkyl, C6R105 with R10 independently selected from H, F, C1-C5 alkyl; ;

[0134] W is selected from O and S, preferably O;

[0135] R' is a substituent selected from the group consisting of F, C1-C4 alkyl, C1-C4 perfluoroalkyl, C1-C4 alkoxy, C1-C4 perfluoroalkoxy; preferably C1-C4 alkyl, C1-C4 perfluoroalkyl, C1-C4 alkoxy, C1-C4 perfluoroalkoxy.

[0136] Preferably, said lithium salt A is of formula (IVa), (IVb), (IVc) or (IVd) in which

[0137] X is a heteroatom selected from the group consisting of O, S and N(R5) wherein R5 is H or C1-C10 alkyl; preferably R5 is H, CH3 or C2H5;

[0138] Y is a group selected from the group consisting of -C(R6)(R7)-, -C(R6)(R 7)C(R6)(R7)SC(R6)(R7)- and -[(O)z(C(R8)(R9)-C(R8)(R9)O)mC(R8)(R9)C(R8)(R9)]- with R6 and R7 independently selected for each carbon atom and for each Y unit from H or F; R8 and R9 independently selected for each carbon atom and for each Y unit from H, F or CH3;

[0139] m an integer from 1 to 50, advantageously from 1 to 40, preferably from 1 to 30, more preferably from 1 to 20, in particular from 1 to 10;

[0140] z = 0ifXisO;

[0141] n is an integer from 1 to 50, advantageously from 1 to 40, preferably from 1 to 30, more preferably from 1 to 20, in particular from 1 to 10;

[0142] A and B are independently of each other selected from the group consisting of H, F, Cl, I, Br, CH3, C2H5, CF3, C2F5, phenyl; preferably A and B are the same and are selected from the group consisting of H, F, Cl, I, Br or A is H and B is selected from the group consisting of F, Cl, Br, I, CH3, C2H5, CF3, C2F5, phenyl;

[0143] V is selected from the group consisting of H, F, Cl, Br, I, C1-C5 alkyl, C1-C5 perfluoroalkyl, C6R105 with R10 independently selected from H, F, C1-C5 alkyl;

[0144] W is selected from O and S, preferably O;

[0145] R' is a substituent selected from the group consisting of F, C1-C4 alkyl, C1-C4 perfluoroalkyl, C1-C4 alkoxy, C1-C4 perfluoroalkoxy; preferably C1-C4 alkyl, C1-C4 perfluoroalkyl, C1-C4 alkoxy, C1-C4 perfluoroalkoxy. Catalyst D

[0146] Said process for preparing said lithium salt A is carried out in the presence of a catalyst D. Advantageously, said catalyst D is a non-nucleophilic compound. The use of a non-nucleophilic compound makes it possible to avoid the degradation of said lithium salt B.

[0147] According to a preferred embodiment, said catalyst D is a compound having a pKa greater than 11 measured at 25°C in water. According to a particular embodiment, said catalyst D has a pKa greater than 11.5, advantageously greater than 12.0, preferably greater than 12.5, in particular greater than 13.0.

[0148] Preferably, the molar ratio of the catalyst relative to said lithium salt B is greater than or equal to 0.1, preferably greater than or equal to 0.2. Preferably, the molar ratio of the catalyst relative to said lithium salt B is less than or equal to 2.5, preferably less than or equal to 2.

[0149] According to a preferred embodiment, said catalyst D is selected from the group consisting of N,N-Diisopropylethylamine, l,8-Diazabicyclo(5.4.0)undec-7-ene, 6-(Dibutylamino)-l,8-diazabicyclo[5.4.0]undec-7-ene, l,8-Diazabicyclo[5.4.0]undec-7-ene bound to polystyrene, l,5,7-Triazabicyclo[4.4.0]dec-5-ene, 7-Methyl-l,5,7-triazabicyclo[4.4.0]dec-5-ene, 1,1,3,3-Tetramethylguanidine, 2-tert-Butyl-1,1,3,3-tetramethylguanidine, l,5,7-Triazabicyclo[4.4.0]dec-5-ene bound to Polystyrene, 1,4-Diazabicyclo[2.2.2]octane, Quinuclidine, l,5-Diazabicyclo(4.3.0)non-5-ene, 2,6-Di-tert-butylpyridine, 2,8,9-Trimethyl-2,5,8,9-tetraza-l-phosphabicyclo[3.3.3]undecane, cyclodi-phosphazane, Lithium diisopropylamide, sodium diisopropylamide, potassium diiso-propylamide, magnésium diisopropylamide, calcium diisopropylamide, rubidium diisopropylamide, lithium bis(trimethylsilyl)amide, sodium bis(trimethylsilyl)amide, potassium bis(trimethylsilyl)amide, magnésium bis(trimethylsilyl)amide, calcium bis(trimethylsilyl)amide, rubidium bis(trimethylsilyl)amide, lithium tetramethylpi-peridide, sodium tetramethylpiperidide, potassium tetramethylpiperidide, magnésium tetramethylpiperidide, calcium tetramethylpiperidide, rubidium tetramethylpiperidide, [18-crown-6]-KHF2, KHF2, N,N’-diisopropylimidazonium, bifluorure, tetrabuty-lammonium. .

[0150] En particulier, ledit catalyseur D est sélectionné parmi le groupe consistant en l,8-Diazabicyclo(5.4.0)undec-7-ene, l,5,7-Triazabicyclo[4.4.0]dec-5-ene, 2-tert-butyl-1,1,3,3-tetramethylguanidine, 1,5,7-Triazabicyclo[4.4.0]dec-5-ene bound to polystyrene and 1,8-Diazabicyclo[5.4.0]undec-7-ene bound to polystyrene. Implementation of the method according to the invention

[0151] The process can be carried out under mild operating conditions. Step a) of the process is preferably carried out in a reactor made of a material such as Inconel®, Hastelloy®, Monel®.

[0152] According to a preferred embodiment, said method is carried out at a temperature of 10 to 70°C, advantageously of 10°C to 50°C, preferably at a temperature of 10°C to 30°C.

[0153] Said method can be carried out at a pressure of 0.5 to 3 bara, preferably at atmospheric pressure; even if the pressure is not an important parameter in the implementation of the method.

[0154] Said method can be carried out under an inert atmosphere or not.

[0155] Preferably, in step a), said lithium salt B is brought into contact with said catalyst D followed by the addition of said compound C. This makes it possible to improve the conversion of the reaction between the lithium salt and the compound C.

[0156] The reaction between lithium salt B and compound C is preferably carried out at stoichiometry or in slight excess or deficiency of compound C. Thus, for example, if said lithium salt B comprises two S(O)2-F groups, 2 eq. of compound C relative to the number of moles of lithium salt B are added.

[0157] Said method can be carried out in the presence of a solvent even if the method can be carried out without solvent. When a solvent is used, it can be for example acetonitrile, benzonitrile, dimethylsulfoxide, dimethyl formamide, 1,4 dioxane, nitromethane, dimethyl carbonate, diethyl carbonate, propyl carbonate, ethylene carbonate, N-methyl-2-pyrrolidone or a mixture thereof.

[0158] In addition to lithium salt A, said product mixture may comprise said unreacted lithium salt B or said unreacted compound C or a mixture of both.

[0159] Said mixture of products may also comprise F-SiR'R2R3 with R1, R2 and R3 as defined in the present application. When R1, R2 and R3 are CH3, the F-Si(CH3)3 formed during step a) is easily removed given its boiling point (Bp = 16°C).

[0160] When said lithium salt B comprises two S(O)2-F groups, said mixture of products may also comprise a compound in which only one of the fluorine atoms has been substituted. For example, when said lithium salt B is LiN(S(O)2-F)2, said mixture of products may comprise LiN(S(O)2F)(S(O)2-OR).

[0161] Said lithium salt B may optionally contain impurities linked to its preparation process, such as LiCl, LiF or FSO3Li in a mass content of less than 1000 ppm, advantageously less than 500 ppm, preferably less than 100 ppm based on the total weight of said lithium salt. In particular, FSO3Li, if present, represents a mass content of less than 5 ppm based on the total weight of said lithium salt B. Other impurities may also be present in said lithium salt B as described in document WO 2018 / 104674. These impurities may optionally be present in said lithium salt A in a content less than or equal to that mentioned for said lithium salt B.

[0162] According to a preferred embodiment, said method also comprises a step b) of purifying said mixture of products obtained in step a) to isolate said lithium salt A. If step a) has been carried out in the presence of a solvent, the latter is preferably evaporated before carrying out step b). Said step b) comprises in particular a step of extracting said lithium salt A with an apolar organic solvent. Said apolar organic solvent is for example a C5-Ci0 alkyl, C5-Ci0 cycloalkyl, C6-Ci0 aryl, C1-C3 haloalkyl, diethyl ether, 1,4-dioxane, tetrahydrofuran or a mixture thereof. Preferably, said apolar organic solvent is n-hexane, pentane, heptane, cyclohexane, cyclopentane, benzene, toluene, xylene, cumene, CCl4, CHC13, diethyl ether, 1,4-dioxane, tetrahydrofuran or a mixture thereof.

[0163] Said process according to the present invention makes it possible to obtain said lithium salt A with a very high purity. The mixture obtained in step b) and comprising said lithium salt and said apolar solvent is distilled to remove the apolar solvent and recovered said lithium salt A. The implementation of step b) makes it possible to obtain a composition comprising at least 95% by weight, preferably at least 98% by weight, in particular at least 99% by weight, more particularly at least 99.5% of lithium salt A based on the total weight of the composition.

[0164] Said composition may comprise less than 1%, preferably less than 0.5% by weight of additional compounds selected from the group consisting of said compound C, said compound B and F-SiR'R2R3 with R1, R2, R3 as defined in the present application. When said lithium salt B is LiN(S(O)2-F)2, said composition may comprise less than 1%, preferably less than 0.5% by weight of additional compounds selected from the group consisting of said compound C, said compound B, F-SiR1 R2R3 and LiN(S(O)2F)(S(O)2-OR) with R, R1, R2, R3 as defined in the present application.

[0165] Lithium salt of formula (Ilia). (Illb), (IIIc), (nest), (nie), (nif), (Illg). (IHh), (Illi). (Illj). fIVa). avb). (IVc) or (IVcD

[0166] According to a second aspect of the present invention, a lithium salt is provided. According to a preferred embodiment, the lithium salt is of the formula (Ilia), (Illb), (IIIc), (ind), (me), (inf), (nig), (nih), (nii), (nij), (iva), (ivb), (ivc) or (ivd) (YV(> ■S— CH.Y')n W BV / / OA—X (Here) YES \ HER (YVO-S- II Oh -S—O-(Y)a It's $ (IHb) Oh / Lead ¥ (YvO- S II O night) 0 II -S“--O-(¥}n or * B” S"" NTM' SY there h ' OO s m<0 B …..X W (YVO 0 S—O-fYMi (island) iW “S Oh >j-~S~O-(Y}fJ The II OO W (Y).rO—S (HIgj V (¥ 11 O S- (Y (Y), O n os- -■CHYjn {H0 ) B 'S—O-(Y)' Oh Y B 0 L1 O W (¥)SO—S s- ( 1 V;s} (IVb) (ï¥d)

[0167] in which

[0168] X is a heteroatom selected from the group consisting of O, S and N(R5) wherein R5 is H or Ci-Cio alkyl;

[0169] Y is a group selected from the group consisting of -C(R6)(R7)-, -C(R6)(R 7)C(R6)(R7)SC(R6)(R7)- and -[(O)z(C(R8)(R9)-C(R8)(R9)O)mC(R8)(R9)C(R8)(R9)]- with R6 and R7 independently selected for each carbon atom and for each Y unit from H or F; R8 and R9 independently selected for each carbon atom and for each Y unit from H, F or CH3;

[0170] m an integer from 1 to 50, advantageously from 1 to 40, preferably from 1 to 30, more preferably from 1 to 20, in particular from 1 to 10;

[0171] z = 0ifXisO;

[0172] n is an integer from 1 to 50, advantageously from 1 to 40, preferably from 1 to 30, more preferably from 1 to 20, in particular from 1 to 10;

[0173] A, B and V are independently of each other selected from the group consisting of H, F, Cl, Br, I, C1-C2O alkyl optionally substituted by one or more substituent(s) R”, C2-C2O alkenyl optionally substituted by one or more substituent(s) R”, C3-C2O cycloalkyl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups, C4-C2O cycloalkenyl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups, C6-C2O aryl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups with R” selected from the group consisting of F, Cl, I, Br, C1-C4 ether, CrC4 ester, CrC4 thioether, Ci-C4 thioester, preferably F, Ci-C4 ether, Ci-C4 ester, Ci-C4 thioether, Ci -C4 thioester;advantageously A, B and V are independently of each other selected from the group consisting of H, F, Cl, Br, I, C1-C15 alkyl optionally substituted by one or more substituent(s) R”, C2-C15 alkenyl optionally; substituted by one or more substituent(s) R”, C3-Ci5 cycloalkyl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups, C4-Ci5 cycloalkenyl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups, C6-Ci5 aryl optionally substituted by one or more substituent(s) R' ' or one or more C1-C5 alkyl groups with R” selected from the group consisting of F, Cl, I, Br, C1-C4 ether, C1-C4 ester, C1-C4 thioether, C1-C4 thioester, preferably F, C1-C4 ether, C1-C4 ester, C1-C4 thioether, C1-C4 thioester;preferably A, B and V are independently of each other selected from the group consisting of H, F, Cl, Br, I, C1-C10 alkyl optionally substituted by one or more substituent(s) R”, C2-C10 alkenyl optionally substituted by one or more substituent(s) R”, C3-C10 cycloalkyl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups, C4-C10 cycloalkenyl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups, C6 -C10 aryl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups with R” selected from the group consisting of F, Cl, I, Br, C1-C4 ether, C1-C4 ester, C1-C4 thioether, C1-C4 thioester, preferably F, C1-C4 ether, C1-C4 ester, C1-C4 thioether, C1-C4 thioester;more preferably A, B and V are independently of each other selected from the group consisting of H, F, Cl, Br, I, C1-C10 alkyl, C2-C10 alkenyl, C3-C10 cycloalkyl, C4-C10 cycloalkenyl, C6-C10 aryl, C1-C10 perfluoroalkyl, C2-C10 perfluoroalkenyl, C3-C10 per-fluorocycloalkyl, C4-C10 perfluorocycloalkenyl, C6-C10 perfluoroaryl; in particular A, B and V are independently of each other selected from the group consisting of H, F, Cl, Br, I, C1-C5 alkyl, C1-C5 perfluoroalkyl, C6R105 with R10 independently selected from H, F, C1-C5 alkyl; ;

[0174] W is selected from O and S, preferably O;

[0175] R' is a substituent selected from the group consisting of F, C1-C4 alkyl, C1-C4 perfluoroalkyl, C1-C4 alkoxy, C1-C4 perfluoroalkoxy; preferably C1-C4 alkyl, C1-C4 perfluoroalkyl, C1-C4 alkoxy, C1-C4 perfluoroalkoxy.

[0176] Preferably, said lithium salt is of formula (Ilia), (Illb), (IIIc), (Illd), (Ille), (Illf), (nig), (nih), (Bli), (Illj), (IVa), (IVb), (IVc) or (IVd) in which

[0177] X is a heteroatom selected from the group consisting of O, S and N(R5) wherein R5 is H or C1-C10 alkyl; preferably R5 is H, CH3 or C2H5;

[0178] Y is a group selected from the group consisting of -C(R6)(R7)-, -C(R6)(R 7)C(R6)(R7)SC(R6)(R7)- and -[(O)z(C(R8)(R9)-C(R8)(R9)O)mC(R8)(R9)C(R8)(R9)]- with R6 and R7 independently selected for each carbon atom and for each Y unit from H or F; R8 and R9 independently selected for each carbon atom and for each Y unit from H, F or CH3;

[0179] m an integer from 1 to 50, advantageously from 1 to 40, preferably from 1 to 30, more preferably from 1 to 20, in particular from 1 to 10;

[0180] z = OsiXestO;

[0181] n is an integer from 1 to 50, advantageously from 1 to 40, preferably from 1 to 30, more preferably from 1 to 20, in particular from 1 to 10;

[0182] A and B are independently of each other selected from the group consisting of H, F, Cl, I, Br, CH3, C2H5, CF3, C2F5, phenyl; preferably A and B are the same and are selected from the group consisting of H, F, Cl, I, Br or A is H and B is selected from the group consisting of F, Cl, Br, I, CH3, C2H5, CF3, C2F5, phenyl;

[0183] V is selected from the group consisting of H, F, Cl, Br, I, C1-C5 alkyl, C1-C5 perfluoroalkyl, C6R105 with R10 independently selected from H, F, C1-C5 alkyl;

[0184] W is selected from O and S, preferably O

[0185] R' is a substituent selected from the group consisting of F, C1-C4 alkyl, C1-C4 perfluoroalkyl, C1-C4 alkoxy, C1-C4 perfluoroalkoxy; preferably C1-C4 alkyl, C1-C4 perfluoroalkyl, C1-C4 alkoxy, C1-C4 perfluoroalkoxy.

[0186] In particular, said lithium salt is of formula (Ilia), (Illb), (IIIc), (Illd), (Ille), (Illf), (nig), (nih), (Bli), (Illj), (IVa), (IVb), (IVc) or (IVd) in which

[0187] A and B are independently of each other selected from the group consisting of H, F, Cl, I, Br, CH3, C2H5, CF3, C2F5, phenyl; preferably A and B are the same and are selected from the group consisting of H, F, Cl, I, Br or A is H and B is selected from the group consisting of F, Cl, Br, I, CH3, C2H5, CF3, C2F5, phenyl;

[0188] V is selected from the group consisting of H, F, Cl, Br, I, C1-C5 alkyl, C1-C5 perfluoroalkyl, C6R105 with R10 independently selected from H, F, C1-C5 alkyl;

[0189] West O;

[0190] X is O;

[0191] Y is a group selected from the group consisting of CH2CH2, CH2CF2, CF 2CF2, CH2CHF, CF2CH2, CHFCH2, and n is an integer from 1 to 25; or

[0192] Y is a group -[(C(R8)(R9)-C(R8)(R9)O)mC(R8)(R9)C(R8)(R9)]- with R8 and R9 independently selected for each carbon atom and for each Y unit from H, F or CH3, m is an integer from 1 to 25 and n is 1;

[0193] R' is a substituent selected from the group consisting of F, C1-C4 alkyl, C1-C4 perfluoroalkyl, C1-C4 alkoxy, C1-C4 perfluoroalkoxy; preferably C1-C4 alkyl, C1-C4 perfluoroalkyl, C1-C4 alkoxy, C1-C4 perfluoroalkoxy.

[0194] According to a preferred embodiment, said lithium salt is of formula (I11a) in which

[0195] A and B are H,

[0196] VestCH3ouH,

[0197] W is O,

[0198] X is O and

[0199] Y is a group selected from the group consisting of CH2CH2, CH2CF2, CF 2CF2, CH2CHF, CF2CH2, CHFCH2, and n is an integer from 1 to 10; or

[0200] Y is a group -[(C(R8)(R9)-C(R8)(R9)O)mC(R8)(R9)C(R8)(R9)]- with R8 and R9 independently selected for each carbon atom and for each Y unit from H, F or CH3, m is an integer from 1 to 25 and n is 1. Examples Example 1

[0201] In a 50 ml reactor, 1.06 g of LiFSI are dissolved in 20 ml of acetonitrile at room temperature (22 °C). To this solution, 1.5 ml of l,8-Diazabicyclo(5.4.0)undec-7-ene (2 eq. relative to LiFSI - pKa of 13.5 at 25 °C in water) are added and mixed for 5 minutes, followed by the addition of 2.54 ml of 2-(Trimethylsiloxy)ethyl methacrylate (2 eq. relative to LiFSI). The reaction mixture is stirred at room temperature for 24 h under ambient atmosphere. The acetonitrile is evaporated via a rotary evaporator at 30 °C and 1 mbar. The residue is mixed with petroleum ether until two phases are obtained. The upper phase containing lithium salt A and petroleum ether is separated and the petroleum ether is evaporated via a rotary evaporator at 30°C and 1 mbar. The recovered product is the lithium salt of formula (Ilia) with A and B = H, V = CH3, W = O, X = O and Y is CH2CH2; n = 1. The conversion of LiFSI is 100%.The purity of lithium salt is greater than 99%.

[0202] 'H NMR (400 MHz, DMSO-d6) ô 6.06 (dd, J = 1.7, 0.9 Hz, 2H), 5.75 - 5.53 (m, 2H), 4.15 - 4.00 (m, 4H), 3.68 - 3.53 (m, 4H), 1.94 - 1.67 (m, 6H). Example 2

[0203] Example 1 is reproduced with an amount of 0.17 ml of l,8-Diazabicyclo(5.4.0)undec-7-ene (0.2eq. relative to LiFSI). The recovered product is the lithium salt of formula (Ilia) with A and B = H, V =CH3, W = O, X = O and Y is CH2CH2; n = 1. The conversion of LiFSI is 100%. The purity of the lithium salt is greater than 99%. Comparative example 1

[0204] Example 1 is reproduced with 2.16 ml of triethylamine (2 eq. relative to LiFSI). Triethylamine has a pKa less than 11. The recovered product is the lithium salt of formula (I11a) with A and B = H, V = CH3, W = O, X = O and Y is CH2CH2; n = 1. LiFSI conversion is 8%.

Claims

Claims

1. A process for preparing a lithium salt A comprising a step a) of bringing a lithium salt B comprising at least one -S(O)2-F group into contact with a compound C of formula (I) RO-SiR'R2R3 in the presence of a catalyst D to form a mixture of products comprising said lithium salt A comprising at least one -S(O)2-OR group; said catalyst D being a compound having a pKa greater than 11 measured at 25°C; characterized in that: said lithium salt B is Li-N(S(O)2-F)2 and said lithium salt A is of formula (III) Li-N(S(O)2-OR)2 or said lithium salt B is of formula LiN(S(O)2-F)(S(O)2R') and said lithium salt A is of formula (IV) LiN(S(O)2-OR)(S(O)2R') wherein R' is a substituent selected from the group consisting of F, C1-C4 alkyl, C1-C4 perfluoroalkyl, C1-C4 alkoxy, C1-C4 perfluoroalkoxy; preferably C1-C4 alkyl, C1-C4 perfluoroalkyl, C1-C4 alkoxy, C1-C4 perfluoroalkoxy; said compound C is of formula (I) RO-SiR'R2R3 in which R1, R2 and R3 are independently of each other selected from the group consisting of H, CrC2o alkyl, C3-C20 cycloalkyl, C6-C20 aryl; R is of formula R4-X-(Y)n- wherein X is a heteroatom selected from the group consisting of O, S and N(R5) wherein R5 is H or C1-C10 alkyl; Y is a group selected from the group consisting of -C(R6)(R7)-, -C(R6)(R7)C(R6)(R7)SC(R6)(R7)- and -[(O)Z(C(R8)(R9)-C(R8)(R9)O)mC(R8)(R9)C(R8)(R9)]- with R6 and R7 independently selected for each carbon atom and for each Y unit from H or F, R8 and R9 independently selected for each carbon atom and for each Y unit from H, F or CH3, m an integer from 1 to 50, z = 0 if X is O; n is an integer from 1 to 50; R4 is of formula (la), (Ib), (le) or (Id): wherein A, B and V are independently selected from the group consisting of H, F, Cl, Br, I, C1-C10 alkyl optionally substituted by one or more substituent(s) R”, C2-C10 alkenyl optionally substituted by one or more substituent(s) R”, C3-C10 cycloalkyl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups, C4-C10 cycloalkenyl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups, C6-C12 aryl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups; W is selected from O and SR” is selected from the group consisting of F, Cl, I, Br, C1-C4 ether, C1-C4 ester, C1-C4 thioether, C1-C4 thioester, preferably F, CrC 4 ether, C1-C4 ester, C1-C4 thioether, CrC4 thioester.

2. Process according to the preceding claim, characterized in that said compound C is of formula (I) RO-SiR'R2R3 in which the groups R1, R2 and R3 are independently of each other selected from the group consisting of H and Ci-Cio alkyl.

3. A process according to any one of the preceding claims characterized in that said catalyst D is selected from the group consisting of N,N-Diisopropylethylamine, l,8-Diazabicyclo(5.4.0)undec-7-ene, 6-(Dibutylamino)-l,8-diazabicyclo[5.4.0]undec-7-ene, l,8-Diazabicyclo[5.4.0]undec-7-ene bound to polystyrene, l,5,7-Triazabicyclo[4.4.0]dec-5-ene, 7-Methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 1,1,3,3-Tetramethylguanidine, 2-tert-Butyl-1,1,3,3-tetramethylguanidine, l,5,7-Triazabicyclo[4.4.0]dec-5-ene bound to polystyrene, 1,4-Diazabicyclo[2.2.2]octane, Quinuclidine, l,5-Diazabicyclo(4.3.0)non-5-ene, 2,6-Di-tert-butylpyridine, 2,8,9-Trimethyl-2,5,8,9-tetraza-1 -phosphabicyclo[3.3.3]undecane, Cy-clodiphosphazane, Lithium diisopropylamide, sodium diisopropylamide, potassium diisopropylamide, magnésium diisopropylamide, calcium diisopropylamide, rubidium diisopropylamide, lithium bis(trimethylsilyl)amide, sodium bis(trimethylsilyl)amide, potassium bis(trimethylsilyl)amide, magnésium bis(trimethylsilyl)amide, calcium. [Revendication 4] [Revendication 5] [Revendication 6] bis(trimethylsilyl)amide, rubidium bis(trimethylsilyl)amide, lithium tetramethylpiperidide, sodium tetramethylpiperidide, potassium tetramethylpiperidide, magnesium tetramethylpiperidide, calcium tetramethylpiperidide, rubidium tetramethylpiperidide, [18-crown-6]-KHF2, KHF2, N,N'-diisopropylimidazonium, bifluoride, tetrabutylammonium. Process according to any one of the preceding claims, characterized in that it also comprises a step b) of purifying said lithium salt A; said step b) comprising the extraction of said lithium salt A with a non-polar organic solvent. Method according to any one of the preceding claims, characterized in that step a) is carried out at a temperature of 10 to 50°C. Lithium salt of formula (Ilia), (Illb), (IIIc), (Illd), (Ille), (Illf), (Illg), (Hlh), (Hli), (Illj), (IVb), (IVc) or (IVd) (JVb) B Vx Q o V (YVO—N — S— R- Oh 6

7. {IVd> in which the substituents A, B, V, W, X, Y, R' and n are as defined in claim 1. Lithium salt according to the preceding claim of formula (Ilia), (Illb), (nie), (nid), (nie), (iiif), (nig), (nih), (nii), (iiij), (ivb), (ivc) or (IVd) in which A and B are the same and are selected from the group consisting of H, F, Cl, Br and I; V is selected from the group consisting of H, F, Cl, Br, I, C1-C10 alkyl optionally substituted by one or more substituent(s) R”, C2-C10 alkenyl optionally substituted by one or more substituent(s) R”, C3-C10 cycloalkyl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups, C4-C10 cycloalkenyl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups, C6-C12 aryl optionally substituted by one or more substituent(s) R” or one or more C1-C5 alkyl groups with R” is selected from the group consisting of F, Cl, I, Br, C1-C4 ether, C1-C4 ester, C1-C4 thioether, C1-C4 thioester; preferably V is selected from the group consisting of H, F, Cl, Br, I, C1-C5 alkyl, C1-C5 perfluoroalkyl, C6R106 with R10 independently selected from H, F, C1-C5 alkyl; W is O; X is O; Y is a group selected from the group consisting of CH2CH2, CH2CF2, CF2CF2, CH2CHF, CF2CH2, CHFCH2, and n is an integer from 1 to 25; or Y is a group -[(C(R8)(R9)-C(R8)(R9)O)mC(R8)(R9)C(R8)(R9)]-with R8 and R9 independently selected for each carbon atom and for each Y unit from H, F or CH3, m is an integer from 1 to 25 and n is 1; R' is a substituent selected from the group consisting of F, C1-C4 alkyl, C1-C4 perfluoroalkyl, C1-C4 alkoxy, C1-C4 perfluoroalkoxy; preferably C1-C4 alkyl, C1-C4 perfluoroalkyl, C1-C4 alkoxy, C1-C4 perfluoroalkoxy.

8. A lithium salt according to any one of the preceding claims 6 or 7 of formula (Ilia), (Illb), (IIIc), (Illd), (Ille), (Illf), (Illg), (Illh), (Illi), (Illj), (IVb), (IVc) or (IVd) wherein A and B are H, V is CH 3, W is 0, X is 0 and Y is a group selected from the group consisting of CH2CH2, CH2CF2, CF2CF2, CH2CHF, CF2CH2, CHFCH2, and n is an integer from 1 to 10; or Y is a group -[(C(R8)(R9)-C(R8)(R9)O)mC(R8)(R9)C(R8)(R9)]-with R8 and R9 independently selected for each carbon atom and for each Y unit from H, F or CH3, m is an integer from 1 to 25 and n is 1; R' is a substituent selected from the group consisting of F, C1-C4 alkyl, C1-C4 perfluoroalkyl, C1-C4 alkoxy, C1-C4 perfluoroalkoxy.

9. A lithium salt of formula (Ilia) according to any one of preceding claims 6 to 8 wherein A and B are H, V is CH3, W is 0, X is 0 and Y is a group selected from the group consisting of CH2CH2, CH2CF2, CF2CF2, CH2CHF, CF2CH2, CHFCH2, and n is an integer from 1 to 10; or Y is a group -[(C(R8)(R9)-C(R8)(R9)O)mC(R8)(R9)C(R8)(R9)]-with R8 and R9 independently selected for each carbon atom and for each unit Y from H, F or CH3, m is an integer from 1 to 25 and n is 1.

10. Lithium salt of formula (IVa) AV \ / b kx ? ; o W (Yf^O—S—N—S—R: Ô Ô (Wa.) wherein A and B are H, V is CH3, W is 0, X is 0 and Y is a group selected from the group consisting of CH2CH2, CH2CF2, CF2CF2, CH2CHF, CF2CH2, CHFCH2, and n is an integer from 1 to 10; or Y is a group -[(C(R8)(R9)-C(R8)(R9)O)mC(R8)(R9)C(R^^^ with R8 and R9 independently selected for each carbon atom and for each Y unit from H, F or CH3, m is an integer from 1 to 25 and n is 1; R' is as defined in claim 1.