Process for preparing unipolar cation-conducting ionomers from difluoro ionic monomers

Abstract

The invention relates to a process for preparing unipolar cation-conducting ionomers from fluoro ionic monomers, to said unipolar cation-conducting ionomers, to the uses thereof, to an electrolytic composition comprising at least one of said unipolar cation-conducting ionomers and to an electrochemical device comprising at least one of said unipolar cation-conducting ionomers, especially as electrolyte.

Claims

1. Process for preparing an ionomer comprising at least repeating units UP corresponding to formula (II) below: ##STR00033## in which M is an alkali metal cation, an alkaline-earth metal cation, a transition metal cation, a poor metal cation, an ammonium, a sulfonium or a phosphonium of valency m, with 1m3, m being an integer, A.sup.a- is an anion chosen from a sulfonate anion, a sulfonimide anion of formula SO.sub.2N.sup.SO.sub.2R, an anion derived from a sulfonimide anion bearing at least two negative charges, and a carbanion of formula SO.sub.2C.sup.RR, with 1a3, a being an integer, with R representing a fluorine atom; an optionally fluoro or perfluoro alkyl group, containing from 1 to 10 carbon atoms; an optionally fluoro or perfluoro alkoxy group, containing from 1 to 10 carbon atoms; a phenoxy group optionally substituted with an electron-withdrawing group X.sup.2; an optionally fluoro or perfluoro dialkyl ether group, containing from 1 to 10 carbon atoms; a thiocyanate group; an optionally substituted phenyl group; a nitrile group; an amino group of formula NR.sup.1R.sup.2, in which R.sup.1 and R.sup.2 are chosen, independently of each other, from the following groups: an optionally fluoro or perfluoro alkyl group, containing from 1 to 5 carbon atoms, an alkyl group containing from 1 to 5 carbon atoms and bearing an electron-withdrawing group X.sup.3, an optionally fluoro or perfluoro dialkyl ether group, containing from 1 to 5 carbon atoms, and an electron-withdrawing group X.sup.4; a group NR.sup.3 being chosen from a saturated heterocycle containing from 3 to 6 carbon atoms and an unsaturated heterocycle containing from 4 to 6 carbon atoms; an amide group of formula NHCOR.sup.4 or N(CH.sub.3)COR.sup.4, in which R.sup.4 is an alkyl group containing from 1 to 3 carbon atoms; a sulfonamide group of formula NHSO.sub.2R.sup.5 or N(CH.sub.3)SO.sub.2R.sup.5, in which R.sup.5 is an alkyl group containing from 1 to 3 carbon atoms; a urethane group of formula NHCO.sub.2R.sup.6 or N(CH.sub.3)CO.sub.2R.sup.6, in which R.sup.6 is an alkyl group containing from 1 to 3 carbon atoms; a cyanamide group of formula NHCN or N(R.sup.7)CN, in which R.sup.7 is an alkyl group containing 1 to 3 carbon atoms; a dicyanamide group N(CN).sub.2; a tricyanomethyl group C(CN).sub.3; or a dicyanomethylene group of formula CH(CN).sub.2 or CR.sup.8(CN).sub.2, in which R.sup.9 is an alkyl group containing 1 to 3 carbon atoms, with R and R being chosen, independently of each other, from the following monovalent groups: a fluorine atom; a thiocyanate group; a nitrile group; a nitro group; a nitroso group of formula R.sup.9NO, in which R.sup.9 is an alkyl group containing from 1 to 3 carbon atoms; a carbonyl group of formula COR.sup.10 in which R.sup.10 is a perfluoro alkyl group containing from 1 to 5 carbon atoms; a sulfoxide group of formula SOR.sup.11 in which R.sup.11 is an optionally fluoro or perfluoro alkyl group, containing from 1 to 5 carbon atoms or an optionally fluoro or perfluoro dialkyl ether group, containing from 1 to 5 carbon atoms; a sulfonyl group of formula SO.sub.2R.sup.12 in which R.sup.12 is a fluorine atom, a thiocyanate group, a nitrile group, an optionally fluoro or perfluoro alkoxy group, containing from 1 to 5 carbon atoms, an optionally fluoro or perfluoro alkyl group, containing from 1 to 5 carbon atoms or an optionally fluoro or perfluoro dialkyl ether group, containing from 1 to 5 carbon atoms; a carboxylic ester group of formula COOR.sup.13, in which R.sup.13 is an alkyl group containing from 1 to 5 carbon atoms; an amide group of formula CONHR.sup.14 in which R.sup.14 is an alkyl group containing from 1 to 5 carbon atoms; an amide group of formula CONR.sup.14R.sup.15 in which R.sup.14 and R.sup.15 are chosen, independently of each other, and R.sup.15 is an alkyl group containing from 1 to 5 carbon atoms; an optionally substituted phenyl group; or an optionally substituted phenoxy group, or with R and R being divalent groups such that the resulting carbanion radical C.sup.RR forms an aromatic ring comprising from 5 to 6 carbon atoms and optionally one or more heteroatoms O or N, said aromatic ring being optionally substituted with one or more nitrile groups, 1n4, n being an integer, 0n2, n being an integer, Z.sup.1 is chosen from a single bond, an oxygen atom, a sulfur atom, a group SO, a group S(O).sub.2 and a phenyl group optionally substituted in the ortho position relative to one of the functions (CF.sub.2).sub.n or (CF.sub.2).sub.n, Z.sup.2 is chosen from a single bond, an oxygen atom, a sulfur atom, a group SO, a group S(O).sub.2 and a group CO, it being understood that when n=0, Z.sup.2 is a single bond, E is an aromatic group comprising from 5 to 20 carbon atoms, it being understood that E comprises from 1 to 3 aromatic rings, and P is an alkylene oxide polymer chain, wherein said process comprises at least one step a) of polycondensation of at least one difluoro ionic monomer (I) with at least one alkylene oxide polymer P.sup.1 in basic medium, said difluoro ionic monomer corresponding to formula (I) below: ##STR00034## in which: A, n, n, Z.sup.1, Z.sup.2, E, m, a and M are as defined above, and T.sup.1 and T.sup.2 are fluorine atoms.

2. Process according to claim 1, wherein the alkylene oxide polymer P.sup.1 used in step a) is chosen from the polymers having the following formulae:
H[O(CH.sub.2).sub.x].sub.yOH, in which 2x4, 1y50,
H[OCH.sub.2CHR.sup.18].sub.yOH, in which R.sup.18 is an alkyl group containing from 1 to 8 carbon atoms or an alkoxy group containing from 1 to 8 carbon atoms, and 1y50,
H[O(CH.sub.2).sub.xiO(CH.sub.2CHR.sup.19).sub.xii].sub.yOH, in which 1xi4; 1xii2; R.sup.19 is a hydrogen atom or an alkyl group containing from 1 to 8 carbon atoms; 1y50,
NH.sub.2CHR.sub.20CH.sub.2[OCH.sub.2CHR.sup.20].sub.yNH.sub.2, in which R.sup.20 is an alkyl group containing from 1 to 8 carbon atoms; and 1y50, and
NH.sub.2CHR.sup.21CH.sub.2O[CH.sub.2CH.sub.2O].sub.yCH.sub.2CHR.sup.21NH.sub.2, in which R.sup.21 is an alkyl group containing from 1 to 8 carbon atoms; and 1y50.

3. Process according to claim 1 wherein said process also comprises, after step a), at least one step b) of placing the ionomer in contact with a compound G comprising at least two functions F.sup.1 that are capable of polycondensing with said ionomer and optionally at least one post-polymerizable function F.sup.2.

4. Process according to claim 3, wherein compound G comprises a post-polymerizable function F.sup.2 and the process also comprises a step c) of post-polymerization of the ionomer obtained on conclusion of step b).

5. Process according to claim 1 wherein said process also comprises, after step a), at least one step d) of placing the ionomer in contact with a compound H comprising a function F.sup.1 that is capable of condensing with said ionomer and optionally at least one post-polymerizable function F.sup.2.

6. Process according to claim 1 wherein said process also comprises, after step a), at least one step f) of placing the ionomer in contact with a compound J that is capable of reacting with said ionomer according to a radical or ionic polymerization.

7. Process according to claim 1, wherein the difluoro ionic monomer (I) is prepared according to a process comprising at least one step i) of reacting a compound (I-a) with a compound (I-b) according to the following reaction scheme: ##STR00035## or at least one step i) of reacting a compound (I-a) with a compound (I-b) according to the following reaction scheme: ##STR00036## or at least one step i) of reacting a compound (I-a) with a compound (I-b) according to the following reaction scheme: ##STR00037## with Z.sup.1, Z.sup.2, n, n, T.sup.1, T.sup.2, E, A, a, m and M being as defined in the invention, and the groups B and D, the groups B and D and the groups B and D being chosen appropriately so as to be able to react together and E.sup.1 and E.sup.2 being chosen appropriately so as to be able to form the aromatic group E.

8. Process according to claim 1, wherein the difluoro ionic monomer (I) corresponds to any one of the following formulae: ##STR00038## in which M, A, a and m are as defined in claim 1.

9. Ionomer, obtained according to the process as defined in claim 1, said ionomer comprises at least repeating units UP corresponding to formula (II) below: ##STR00039## in which A, n, n, Z.sup.1, Z.sup.2, E, m, a and M are as defined in claim 1, and P is an alkylene oxide polymer chain.

10. Ionomer according to claim 9, wherein the alkylene oxide polymer chain corresponds to any one of the following formulae:
[O(CH.sub.2).sub.x].sub.yO, in which 2x4, 1y50,
[OCH.sub.2CHR.sup.18].sub.yO, in which R.sup.18 is an alkyl group containing from 1 to 8 carbon atoms or an alkoxy group containing from 1 to 8 carbon atoms, and 1y50,
[O(CH.sub.2).sub.xiO(CH.sub.2CHR.sup.19).sub.xii].sub.yO, in which 1xi4; 1xii2; R.sup.19 is a hydrogen atom or an alkyl group containing from 1 to 8 carbon atoms; 1y50,
NHCHR.sup.20CH.sub.2[OCH.sub.2CHR.sup.20].sub.yNH, in which R.sup.20 is an alkyl group containing from 1 to 8 carbon atoms; and 1y50, or
NHCHR.sup.21CH.sub.2O[CH.sub.2CH.sub.2O].sub.yCH.sub.2CHR.sup.21NH.sub.2, in which R.sup.21 is an alkyl group containing from 1 to 8 carbon atoms; and 1y50.

11. Ionomer according to claim 9, wherein the aromatic group E comprises from 5 to 15 carbon atoms.

12. Ionomer according to claim 9, wherein the aromatic group E is chosen from a phenyl group, a benzophenone group, a diphenyl sulfide group and a diphenyl sulfone group.

13. Ionomer according to claim 9, wherein M is a cation of an alkali metal or a cation of an alkaline-earth metal.

14. Ionomer according to claim 9, wherein one or more of the following conditions apply: n=n=2, Z.sup.1 is an oxygen atom, Z.sup.2 is a sulfur atom or a single bond.

15. An ionic liquid comprising: an ionomer obtained according to the process as defined in claim 1.

16. A constituent of a composite comprising: an ionomer obtained according to the process as defined in claim 1.

17. An electrochemical device comprising: an electrolyte manufactured with an ionomer obtained according to the process as defined in claim 1.

18. Electrolytic composition, wherein said electrolytic composition comprises at least one ionomer obtained according to the process as defined in claim 1.

19. Electrolytic composition according to claim 18, wherein said electrolytic composition also comprises one or more organic solvents.

20. Electrolytic composition according to claim 18, wherein said electrolytic composition also comprises one or more additives chosen from mineral fillers, alkali metal salts, organic fillers, complexing agents, flame retardants, and a mixture thereof.

21. Electrolytic composition according to claim 18, wherein said electrolytic composition is constituted solely of said ionomer.

22. Electrochemical device comprising; at least one negative electrode and at least one positive electrode separated by an electrolytic composition, wherein the electrolytic composition is as defined in claim 18.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 show DSC analyses showing heat flow as a function of the temperature from example 11, in accordance with one embodiment

(2) FIG. 2 is an Ion conductivity test between 20 and 90 C. from example 11, in accordance with one embodiment and

(3) FIG. 3 is an ion conductivity test between 20 and 90 C. performed on electrolytic compositions from example 11, in accordance with one embodiment.

DETAILED DESCRIPTION

EXAMPLES

(4) Unless otherwise mentioned, all the starting materials of the examples were used as received from the manufacturers.

(5) The materials prepared (e.g. monomers and/or ionomers) were characterized by:

(6) proton and/or fluorine nuclear magnetic resonance (NMR),

(7) measurement of the ion conductivity by electrochemical impedance spectrometry,

(8) Differential Scanning Calorimetry (DSC),

(9) thermomechanical analysis (also known as Dynamic Mechanical Analysis or DMA),

(10) measurement of the cation transport number by low-frequency impedance spectrometry,

(11) measurement of the molar mass by size exclusion chromatography using a Waters 515 HPLC coupled to a Wyatt Dawn EOS light-scattering multi-angle detector at 690 nm approximately (also known as Size Exclusion Chromatography coupled to Multi-Angle Laser Light Scattering or SEC-MALLS).

(12) The fluorine and hydrogen nuclear magnetic resonance analyses were performed using a machine sold under the brand name Avance III HD by the company Bruker, with the following parameters: frequencies 400.15 MHz for proton NMR (.sup.1H NMR) and 376.52 MHz for fluorine NMR (.sup.19F NMR).

(13) The ion conductivity measurements were taken using an HP 4192A impedance meter sold by the company Hewlett Packard and functioning in the frequency range 5 Hz-13 MHz, the sinusoidal signal amplitude being set at 10 mV. The measurements were taken at a temperature ranging from 20 C. to 90 C. in a thermostatic oven. The measurements were taken every 10 C. after temperature stabilization for 1 hour, especially during the temperature descent. The samples were placed in a glovebox under argon in Swagelok cells. Each measurement was taken twice so as to ensure reproducibility of the ion conductivities determined.

(14) The differential scanning calorimetry analyses were performed with a machine sold under the trade name DSC 1 STARe system by the company Mettler Toledo. They make it possible to obtain the glass transition temperature of the ionomers obtained.

(15) The thermomechanical analyses (i.e. measurement of the storage modulus) were performed using a machine sold under the trade name DMA Q800 by the company TA instruments (Waters).

(16) Size exclusion chromatography was performed on C.sub.18 Agilent 2PLgel-Mixed-D columns using as elution solvent 0.1M sodium nitrate in dimethylformamide. The elution rate of the solvent was 1 ml/min approximately.

(17) The cation transport number was determined by the method described by Sorensen et al. [Electrochimica Acta, 1982, 27, 12, 1671-1675] which uses low-frequency electrochemical impedance spectroscopy. This scattering impedance may be represented by a Warburg impedance included in an equivalent electrical circuit. The cation transport number was measured at about 70 C. in a lithium/electrolyte/lithium symmetrical flexible cell of coffee bag type.

Example 1

Preparation of a Difluoro Ionic Monomer M.SUP.1

(18) The synthetic scheme for obtaining the difluoro ionic monomer M.sup.1 is as follows:

(19) ##STR00023##

1.1) First Step: Synthesis of Compound 1 (lithium 5-iodooctafluoro-3-oxapentanesulfonate)

(20) Compound 1 was obtained by hydrolysis of 5-iodooctafluoro-3-pentanesulfonyl fluoride in an organic solvent in the presence of LiOH (lithine).

(21) In particular, 10.22 g (0.024 mol) of 5-iodooctafluoro-3-pentanesulfonyl fluoride were dissolved in 48 ml of tetrahydrofuran (THF). Next, 2.22 g (0.053 mol) of lithine were introduced into the THF solution and the resulting reaction medium was maintained under vigorous stirring for 12 hours at room temperature and under an inert atmosphere.

(22) Disappearance of the starting material in the reaction medium (i.e. at the end of the hydrolysis) was monitored and controlled by fluorine NMR (.sup.19F NMR) analysis by means of the disappearance of the peak at 52 ppm and corresponding to the fluorine in the SO.sub.2F unit.

(23) The reaction medium was filtered so as to remove the excess lithine and the THF was evaporated off. The residue obtained was dissolved in acetonitrile and then filtered through a filter with a filtration threshold of about 0.2 m. Compound 1 was obtained in a yield of about 85% in the form of a white powder, after evaporation of the acetonitrile and then drying for 24 hours at 80 C. approximately under reduced pressure. It was stored in the absence of air under an inert atmosphere.

(24) Compound 1 was characterized by fluorine NMR:

(25) .sup.19F NMR: (ppm, acetone-d.sub.6)=118.6 (s, CF.sub.2SO.sub.3Li); 86.52 (m, CF.sub.2O); 82.95 (t, CF.sub.2O); 69.06 (s, ICF.sub.2).

(26) A similar process was used to prepare sodium 5-iodooctafluoro-3-oxapentanesulfonate (98% yield, compound 2) and potassium 5-iodooctafluoro-3-oxapentanesulfonate (98% yield, compound 3).

(27) Compound 3 was characterized by fluorine NMR:

(28) .sup.19F NMR: (ppm, acetone-d.sub.6)=118.6 (s, CF.sub.2SO.sub.3K); 86.52 (m, CF.sub.2O); 82.94 (t, CF.sub.2O); 69.10 (s, ICF.sub.2).

1.2) Second Step: Synthesis of Compound M.SUP.1. (potassium 3,5-(difluorophenyl)octafluoro-3-oxapentanesulfonate)

(29) A solution comprising 8.25 g (0.130 mol) of copper(0) and 7.5 ml (0.065 mol) of 1-bromo-3,5-difluorobenzene in 10 ml of distilled dimethyl sulfoxide (DMSO) was prepared. The resulting reaction medium was kept stirring for 1 hour 30 minutes at about 115-120 C.

(30) A solution comprising 15.0 g (0.032 mol) of compound 3 (K.sup.+ form) in 17 ml of DMSO was prepared separately and then added to the reaction medium. The resulting reaction medium was stirred for 3 hours at about 125 C. and then cooled to room temperature, filtered through Celite545 so as to remove the excess copper, and poured into 200 ml of saturated aqueous sodium chloride solution (brine). The compound was extracted 3 times with 200 ml of ethyl acetate. Next, the organic phases were combined, washed once with 400 ml of water, dried over Na.sub.2SO.sub.4 and filtered, and the solvents were evaporated off. The residue obtained (yellowish solid) was washed with hexane and then with toluene and dichloromethane until the washing solvent was transparent. The monomer M.sup.1 was obtained in a yield of about 75%, in the form of a white solid.

(31) The monomer M.sup.1 was characterized by fluorine and proton NMR:

(32) .sup.1H NMR: (ppm, acetone-d.sub.6)=7.34 (t-t, 1H.sub.Ar); 7.50 (d-d, 2H.sub.Ar).

(33) .sup.19F NMR: (ppm, acetone-d.sub.6)=119.11 (s, CF.sub.2SO.sub.3K); 114.34 (t, CF.sub.2Ar); 108.70 (t, 2 F.sub.Ar); 88.38 (m, CF.sub.2O); 83.48 (m, CF.sub.2O).

(34) A similar process was used to prepare the monomer lithium 3,5-(difluorophenyl)octafluoro-3-oxapentanesulfonate (monomer M.sup.1) and the monomer sodium 3,5-(difluorophenyl)octafluoro-3-oxapentanesulfonate (monomer M.sup.1) in respective yields of 76% and 78%.

Example 2

Preparation of a Difluoro Ionic Monomer M.SUP.2

(35) The synthetic scheme for obtaining the difluoro ionic monomer M.sup.2 is as follows:

(36) ##STR00024##

2.1) First Step: Synthesis of Compound 4 (sodium 5-iodooctafluoro-3-oxapentanetrifluoromethanesulfonimide)

(37) 25.82 mmol of trifluoromethanesulfonamide and 49.30 mmol of triethylamine were dissolved in 20 ml of acetonitrile (ACN), freshly distilled over calcium hydride, in a two-necked round-bottomed flask, and the resulting mixture was stirred. 23.47 mmol of 5-iodooctafluoro-3-oxapentanesulfonyl fluoride were then added and the resulting mixture was heated at about 40 C. for 36 to 40 hours.

(38) Disappearance of the starting material in the reaction medium (i.e. at the end of the hydrolysis) was monitored and controlled by fluorine NMR (.sup.19F NMR) analysis by means of disappearance of the peak at 52 ppm and corresponding to the fluorine in the SO.sub.2F unit.

(39) The solvent was evaporated off under reduced pressure at about 40 C. The residue obtained was then dissolved in dichloromethane, washed with 1000 ml of distilled water and dried over magnesium sulfate. The solvents were evaporated off under reduced pressure at about 40 C. The residue obtained was then dissolved in aqueous sodium hydroxide (NaOH) solution so as to have a molar excess of NaOH of about 5%. After stirring for 15 minutes, the water was removed by lyophilization. NaOH allowed exchange between ammonium and sodium. A viscous oil was obtained and was then dissolved in acetonitrile, dried over magnesium sulfate and filtered, and the solvents were evaporated off under reduced pressure at about 40 C. The residue obtained was recrystallized from anisole to give compound 4.

2.2) Second Step: synthesis of the monomer M.SUP.2 .(sodium 3,5-(difluoro-phenyl)octafluoro-3-oxapentanetrifluoromethanesulfonimide)

(40) 4 equivalents of copper(0) (2.265 g, 35.64 mmol) and 2 equivalents of 1-bromo-2,5-difluorobenzene (3.44 g, 17.82 mmol) were dissolved in 10 ml of undistilled DMSO in a round-bottomed flask equipped with a condenser and a thermometer. The resulting reaction medium was stirred for 1 hour 30 minutes at a temperature ranging from 115 to 120 C. approximately and under inert atmosphere. The temperature was then lowered to about 70 C.

(41) A solution comprising 1 equivalent of compound 4 (5 g, 8.91 mmol) in 7 ml of DMSO was prepared separately and was added to the reaction medium. The temperature of the resulting mixture was brought to about 127 C. At the end of the reaction, the resulting mixture was filtered through Celite545 to remove the excess copper, and then poured into 200 ml of saturated aqueous sodium chloride solution. The compound was extracted 3 times with 200 ml of ethyl acetate. The organic phases were then combined, dried over Na.sub.2SO.sub.4, and filtered, and the solvents were evaporated off. The residue obtained was washed with hexane, then with toluene and dichloromethane until the washing solvent was transparent. The monomer M.sup.2 was obtained in a yield of about 70%.

(42) The monomer M.sup.2 was characterized by fluorine and carbon NMR:

(43) .sup.13C NMR: (ppm, acetone-d.sub.6)=120.7 (q, J=321.5 Hz, C9); 112.8 (tt, J=294.6 Hz, J=34.6 Hz, C6); 117.6 (tt, J=287.5 Hz, J=31.3 Hz, C8); 117.9 (tt, J=287.5 Hz, J=37.1 Hz, C7); 163.9 (dd, J=12.6 Hz, J=250.5 Hz, C2); 132.5 (septet, J=9.8 Hz, C4); 111.4 (dt, J=27.7 Hz, J=7.4 Hz, C3); 108.4 (t, J=24.7 Hz, C1); 113.7 (tt, J=255.4 Hz, J=33.1 Hz, C5).

(44) .sup.19F NMR: (ppm, acetone-d.sub.6)=79.87 (s, 3F, F.sub.9); 82.16 (s, 2F, F.sub.6); 88.15 (s, 2F, F.sub.7); 108.53 (s, 2F, F.sub.2); 114.66 (s, 2F, F.sub.5); 117.27 (s, 2F, F.sub.8).

Example 3

Preparation of a Difluoro Ionic Monomer M.SUP.3

(45) The synthetic scheme for obtaining the difluoro ionic monomer M.sup.3 is as follows:

(46) ##STR00025##

3.1) First Step: Synthesis of Compound 3 (potassium 5-iodooctafluoro-3-oxapentanesulfonate)

(47) Compound 3 was obtained by hydrolysis of 5-iodooctafluoro-3-pentanesulfonyl fluoride in an organic solvent in the presence of KOH according to the process as described in Example 1.1).

3.2) Second Step: Synthesis of Compound M.SUP.3 .(potassium (2,4-difluoro-phenyl)octafluoro-3-oxapentanesulfonate)

(48) 1.0 g of 2,4-difluoro-1-iodobenzene (4.08 mmol), 2.23 g of copper bronze (CAS number: 158113-12-3, copper-tin alloy comprising 90% by mass of copper and 10% by mass of tin, 12.2 mmol), 0.064 g of bipyridine (0.41 mmol) in 5 ml of DMSO were placed in a 50 ml three-necked round-bottomed flask equipped with a condenser, under a nitrogen atmosphere and with stirring. The resulting solution was heated to about 80 C. and 0.94 g of compound 3 (2.04 mmol) was then added. The temperature of the reaction medium was increased to about 130 C. and maintained for 5 hours. The reaction medium was cooled and poured into deionized water. The solution was then filtered through Celite545 so as to give a clear filtrate. The solvents were evaporated off and the residue obtained was then extracted with ethyl acetate for 48 hours using a Soxhlet assembly. The organic phase was washed 3 times with aqueous 2M hydrochloric acid (HCl) solution, sodium bicarbonate solution and 3 times with deionized water. The resulting organic phase was dried over sodium sulfate and the solvents were evaporated off under vacuum. The residue obtained was dried under vacuum for 24 hours and then placed in a desiccator containing P205. The ionic monomer M.sup.3 was obtained in a yield of about 70%.

(49) The monomer M.sup.3 was characterized by fluorine and proton NMR:

(50) .sup.1H NMR: (ppm, DMSO-d.sub.6)=7.8 (d-d, 1H.sub.Ar); 7.55 (d-d, 1H.sub.Ar); 7.3 (d-d, 1H.sub.Ar).

(51) .sup.19F NMR: (ppm, DMSO-d.sub.6)=118 (s, CF.sub.2SO.sub.3K); 111.5 (m, CF.sub.2Ar); 108.4 (m, 1 F.sub.Ar); 102.6 (m, 1 F.sub.Ar); 87.5 (m, CF.sub.2O); 82.3 (m, CF.sub.2O).

Example 4

Preparation of a Difluoro Ionic Monomer M.SUP.4

(52) The synthetic scheme for obtaining the difluoro ionic monomer M.sup.4 is as follows:

(53) ##STR00026##

4.1) First Step: Synthesis of the Monomer M.SUP.3

(54) The monomer M.sup.3 was obtained according to the process as described in Example 3.

4.2) Second Step: Synthesis of Compound M.SUP.4 .(3-{1,1,2,2-tetrafluoro-2-[1,1,2,2-tetrafluoro-2(potassiumoxysulfonyl)ethoxy]ethyl}-4,4-difluoro-diphenylsulfide)

(55) 0.64 g of fluorothiophenol (4.9 mmol), 2 g of monomer M.sup.3 (4.46 mmol) and 2.18 g of Cs.sub.2CO.sub.3(6.69 mmol) in 8 ml of DMSO were placed in a 50 ml three-necked round-bottomed flask equipped with a condenser, under a nitrogen atmosphere and with stirring. The resulting solution was heated to about 65 C. for 16 hours and the resulting reaction medium was then diluted in water and extracted with ethyl acetate. The organic phase was washed with water and then dried over magnesium sulfate. The solvents were evaporated off under vacuum to give a residue. Said residue was purified by chromatography using a column of silica of C.sub.18 type and a methanol/water eluent (55/45 v/v). The ionic monomer M.sup.4 was obtained in a yield of about 65%.

(56) The monomer M.sup.4 was characterized by fluorine and proton NMR:

(57) .sup.1H NMR: (ppm, DMSO-d.sub.6)=7.8 (d-d, 1H.sub.Ar); 7.7-7.5 (m, 4H.sub.Ar); 7.3 (d-d, 2H.sub.Ar).

(58) .sup.19F NMR: (ppm, DMSO-d.sub.6)=118 (s, CF.sub.2SO.sub.3K); 112 (m, CF.sub.2Ar); 113.4 (m, 1 F.sub.Ar); 111.2 (m, 1 F.sub.Ar); 87.5 (m, CF.sub.2O); 82.3 (m, CF.sub.2O).

Example 5

Preparation of a Difluoro Ionic Monomer M.SUP.5 .in Accordance with the First Subject of the Invention

(59) The synthetic scheme for obtaining the difluoro ionic monomer M.sup.5 is as follows:

(60) ##STR00027##

5.1) First Step: Synthesis of Monomer M.SUP.4

(61) The monomer M.sup.4 was obtained according to the process as described in Example 4.

5.2) Second Step: Synthesis of Compound M.SUP.5 .(4-{1,1,2,2-tetrafluoro-2-[1,1,2,2-tetrafluoro-2(potassiumoxysulfonyl)ethoxy]ethyl}-3,4-difluoro-diphenyl sulfone)

(62) 2 g of monomer M.sup.4 (3.59 mmol) were placed in 78 ml of methanol in a round-bottomed flask. A solution comprising 4.42 g of oxone (potassium hydrogen persulfate, 7.18 mmol) in 4 ml of water was added to the resulting solution. The resulting reaction medium was stirred at room temperature for 5 hours. The reaction medium was then poured into aqueous 1M HCl solution and extracted with ethyl acetate. The organic phases were combined and washed with aqueous 1M HCl solution and saturated NaCl solution and then dried over sodium sulfate. The solvents were evaporated off under vacuum to give a residue. Said residue was purified by chromatography using a column of silica of C.sub.18 type and a methanol/water eluent 55/45 v/v). The ionic monomer M.sup.5 was obtained in a yield of about 60%.

(63) The monomer M.sup.5 was characterized by fluorine and proton NMR:

(64) .sup.1H NMR: (ppm, DMSO-d.sub.6)=8.2 (m, 3H.sub.Ar); 7.95 (s and d, 2H.sub.Ar); 7.5 (d-d, 2H.sub.Ar).

(65) .sup.19F NMR: (ppm, DMSO-d.sub.6)=118 (s, CF.sub.2SO.sub.3K); 111.3 (m, CF.sub.2Ar); 108.7 (m, 1 F.sub.Ar); 103.4 (m, 1 F.sub.Ar); 86.9 (m, CF.sub.2O); 82.2 (m, CF.sub.2O).

Example 6

Preparation of a Difluoro Ionic Monomer M.SUP.6

(66) The synthetic scheme for obtaining the difluoro ionic monomer M.sup.6 is as follows:

(67) ##STR00028##

6.1) First Step: Synthesis of Compound 3 (potassium 5-iodooctafluoro-3-oxapentanesulfonate)

(68) Compound 3 was obtained by hydrolysis of 5-iodooctafluoro-3-pentanesulfonyl fluoride in an organic solvent in the presence of KOH according to the process as described in Example 1.1).

6.2) Second Step: Synthesis of Compound M.SUP.6 .(3-{1,1,2,2-tetrafluoro-2-[1,1,2,2-tetrafluoro-2(potassiumoxysulfonyl)ethoxy]ethyl}-4,4-difluoro-benzophenone)

(69) 6.5 g of 4,4-difluoro-3-iodobenzophenone (18.89 mmol), 13.24 g of copper bronze (72.65 mmol) and 0.45 g of bipyridine (2.9 mmol) were placed in 30 ml of DMSO in a 250 ml three-necked round-bottomed flask equipped with a condenser, under a nitrogen atmosphere and with stirring. The resulting solution was heated to about 80 C., and 6.7 g of compound 3 (14.53 mmol) were then added. At the same time, the temperature of the reaction medium was increased to about 130 C. and maintained for 6 hours. The reaction medium was cooled and poured into deionized water. The solution was then filtered through Celite545 so as to give a clear filtrate. The solvents were evaporated off and the residue obtained was then extracted with ethyl acetate for 48 hours using a Soxhlet assembly. The solvents were evaporated off under vacuum and the ionic monomer M.sup.6 was obtained in a yield of about 70%.

(70) The monomer M.sup.6 was characterized by fluorine and proton NMR:

(71) .sup.1H NMR: (ppm, DMSO-d.sub.6)=8.1 (m, 1H.sub.Ar); 7.92 (d-d, 1H.sub.Ar); 7.7 (2 d, 2H.sub.Ar); 7.34 (d-d, 1H.sub.Ar); 7.4 (2 d, 2H.sub.Ar).

(72) .sup.19F NMR: (ppm, DMSO-d.sub.6)=118 (s, CF.sub.2SO.sub.3K); 112.4 (m, CF.sub.2Ar); 107.2 (m, 1 F.sub.Ar); 103.2 (m, 1 F.sub.Ar); 87.5 (m, CF.sub.2O); 82.3 (m, CF.sub.2O).

Example 7

Preparation of Cation-Conducting Ionomers I.SUP.1 .and I.SUP.1 in Accordance with the Second Subject of the Invention

(73) The synthetic scheme for obtaining the ionomers I.sup.1 and I.sup.1 is as follows:

(74) ##STR00029##

(75) 0.268 g of NaH (10.65 mmol, 2.3 equivalents) was placed in a three-necked round-bottomed flask under an argon atmosphere. A solution of 4.62 g of polyethylene glycol of molar mass 1000 g/mol (PEG 1000, y=22.7) (4.62 mmol, 1 equivalent) in 10 ml of diglyme was prepared in another flask. 2 to 3 ml of diglyme were then added to the flask containing the NaH and the resulting solution was added slowly to the solution containing the PEG 1000. The resultant reaction medium was heated at about 65 C. for 3 hours 30 minutes under an argon atmosphere.

(76) In another flask, a solution containing 2 g of the monomer M.sup.1 sodium 3,5-(difluorophenyl)octafluoro-3-oxapentanesulfonate as prepared in Example 1 (4.62 mmol, 1 equivalent) in 5 ml of diglyme was prepared and the solution was added slowly to the reaction medium. The resulting reaction medium was heated at about 140 C. for 24 hours. It was then cooled to room temperature and precipitated from pentane to give a solid containing the ionomer I.sup.1. The solid was filtered off and then dissolved in acetonitrile. The solution obtained was filtered so as to remove the inorganic salts. The filtrate was evaporated on a rotavapor so as to obtain the ionomer in the form of a viscous liquid. This liquid was dried under vacuum at 100 C. for 48 hours.

(77) Exchange of the sodium cation with the lithium cation was performed by ultrafiltration. The ionomer I.sup.1 was dissolved in aqueous 1M LiCl solution and then filtered under pressure with a membrane sold by the company Millipore under the commercial reference Ultracel 3 kDa by the company Sodipro with a cutoff threshold of 1000 g/mol approximately (cellulose ultrafiltration membrane). The NaCl formed was also soluble in water, but passed through the membrane. When the solution became viscous, several aqueous 1M LiCl solutions were added so as to saturate the medium with lithium ions so as to better promote the exchange between the cations. Washing with water to remove a maximum amount of the NaCl formed was performed several times. This operation was performed for at least 24 hours and the resulting solution was then lyophilized. The residue obtained was dissolved in acetonitrile and filtered with filter paper and then with microfilters of about 0.2 m so as to remove the excess LiCl and the remaining NaCl. The solvents were evaporated off under reduced pressure (10.sup.2 bar) and the ionomer I.sup.1 obtained was dried under vacuum at about 60 C. for 24 hours (yield after drying of about 71%).

(78) The ionomer I.sup.1 was characterized by fluorine, carbon and proton NMR:

(79) .sup.1H NMR: (ppm, actone-d.sub.6)=6.92 (s, 2H, H.sub.3); 6.74 (s, 1H, H.sub.1); 4.25 (t, 4H, H.sub.9, J=3.9 Hz); 3.84 (t, 4H, H.sub.10, J=3.9 Hz); 3.62 (s, 90H, H.sub.11, O(CH.sub.2CH.sub.2O)).

(80) .sup.13C NMR: (ppm, acetone-d.sub.6)=162.1 (s, 2C, C.sub.2); 132.5 (t, 1C, C.sub.4, J=24.9 Hz); 107.3 (t, 2C, C.sub.3, J=5.9 Hz); 107.1 (s, 1C, C.sub.1); 113.9 (m, 1C, C.sub.6); 119.4 (m, 1C, C.sub.8); 122.1 (m, 1C, C.sub.7); 116.7 (m, 1C, C.sub.5); 73.0 (s, 2C, C.sub.9); 71.8 (s, 45C, C.sub.11, (CH.sub.2CH.sub.2O).sub.n); 69.9 (s, 2C, C.sub.10).

(81) .sup.19F NMR: (ppm, acetone-d.sub.6)=83.37 (s, 2F, F.sub.6); 88.08 (s, 2F, F.sub.7); 113.88 (s, 2F, F.sub.5); 118.80 (s, 2F, F.sub.8).

(82) The number-average molar mass M.sub.n of the ionomer I.sub.1 was 21 000 g/mol approximately and its mass-average molar mass M.sub.2 was 36 700 g/mol approximately.

(83) The ionomer I.sub.1 had a value p of about 15 and a value y of about 22.7.

Example 8

Preparation of Cation-Conducting Ionomers I.SUP.2.; I.SUP.2., I.SUP.3 and I^{3 .in Accordance with the Second Subject of the Invention}

(84) The synthetic scheme for obtaining the ionomers I.sup.2; I.sup.2, I.sup.3 and I.sup.3 is as follows:

(85) ##STR00030##

(86) 0.315 g of NaH (12.5 mmol, 2.7 equivalents) was placed in a three-necked round-bottomed flask under an argon atmosphere. A solution of 5.32 g of polyethylene glycol of molar mass 1000 g/mol (PEG 1000, n=22.7) (5.32 mmol, 1.15 equivalents) in 6 ml of diglyme was prepared in another flask. 2 to 3 ml of diglyme were then added to the flask containing the NaH and the resulting solution was added slowly to the solution containing the PEG 1000. The resulting reaction medium was heated at about 65 C. for 3 hours 30 minutes under an argon atmosphere.

(87) A solution containing 2 g of the monomer M.sup.1 sodium 3,5-(difluorophenyl)octafluoro-3-oxapentanesulfonate as prepared in Example 1 (4.62 mmol, 1 equivalent) in 3 ml of diglyme was prepared in another flask and the solution was added slowly to the reaction medium. The resulting reaction medium was heated at about 140 C. for 24 hours. It was then cooled to about 60 C. and 7.18 mmol of ground NaOH were added. The resulting reaction medium was stirred for about 2 hours.

(88) Next, 0.7 mmol of 3-chloro-2-chloroprop-1-ene was added and the resulting reaction medium was stirred for about 12 hours. The solid was filtered off and then dissolved in acetonitrile. The solution obtained was filtered so as to remove the inorganic salts. The filtrate was evaporated on a rotavapor so as to obtain the ionomer in the form of a viscous liquid. This liquid was dried under vacuum at 100 C. for 48 hours (yield of ionomer I.sup.2 of about 79%).

(89) The number-average molar mass M.sub.n of the ionomer I.sup.1 obtained was about 7600 g/mol and its mass-average molar mass M.sub.w was about 13 100 g/mol.

(90) The ionomer I.sup.1 had a value p of about 5.5 and a value y of about 22.7.

(91) The ionomer I.sup.2 was characterized by fluorine, carbon and proton

(92) NMR:

(93) .sup.1H NMR: (ppm, acetone-d.sub.6)=6.92 (s, 2H, H.sub.3); 6.74 (s, 1H, H.sub.1); 5.16 (s, 2H, H.sub.14); 4.26 (s, 4H, H.sub.9); 4.00 (s, 4H, H.sub.12); 3.84 (s, 4H, H.sub.10); 3.62 (s, 90H, H.sub.11, O(CH.sub.2CH.sub.2O)).

(94) .sup.13C NMR: (ppm, acetone-d.sub.6)=162.1 (s, 1C, C.sub.2); 145.5 (s, 1C, C.sub.13); 132.5 (t, 1C, C.sub.4, J=24.9 Hz); 107.3 (t, 2C, C.sub.3, J=5.9 Hz); 107.1 (s, 1C, C.sub.1); 113.9 (m, 1C, C.sub.6); 119.4 (m, 1C, C.sub.8); 122.1 (m, 1C, C.sub.7); 116.7 (m, 1C, C.sub.5); 73.0 (s, 4C, C.sub.9); 71.8 (s, 45C, C.sub.11, (CH.sub.2CH.sub.2O).sub.n); 71.1 (s, 4C, C.sub.12); 69.9 (s, 4C, C.sub.10).

(95) .sup.19F NMR: (ppm, acetone-d.sub.6)=83.28 (s, 2F, F.sub.6); 87.95 (s, 2F, F.sub.7); 113.58 (s, 2F, F.sub.5); 118.68 (s, 2F, F.sub.8).

(96) The ionomer I.sup.2 (in lithiated form) was obtained by cation exchange of the ionomer I.sup.2 according to the following ultrafiltration protocol:

(97) The ionomer I.sup.2 was dissolved in aqueous 1M LiCl solution and then filtered under pressure with a cellulose ultrafiltration membrane having a cutoff threshold of about 1000 g/mol as defined in Example 7. The NaCl formed was also soluble in water, but passed through the membrane. When the solution became viscous, several aqueous 1M LiCl solutions were added so as to saturate the medium with lithium ions so as to better promote the exchange between the cations. Washing with water in order to remove a maximum amount of NaCl formed was performed several times. This operation was performed for at least 24 hours and the resulting solution was then lyophilized. The residue obtained was dissolved in acetonitrile and filtered with a paper filter and then with microfilters of about 0.2 m so as to remove the excess LiCl and the remaining NaCl. The solvents were evaporated off under reduced pressure (10.sup.2 bar) and the ionomer I.sup.2 obtained was dried under vacuum at about 60 C. for 24 hours (yield of ionomer I.sup.2 of about 79%).

(98) The number-average molar mass M.sub.n of the ionomer I.sup.2 was about 22 100 g/mol and its mass-average molar mass M.sub.w was about 38 100 g/mol.

(99) The ionomer I.sup.2 had a value y of about 22, a value p of about 5.5 and a value q.sub.3 of about 3.

(100) The ionomers I.sup.2 and I.sup.2 were then crosslinked according to the following protocol:

(101) 1 g of ionomer I.sup.2 or I.sup.2 was dissolved in 10 ml of acetonitrile containing 0.02 g of Irgacure2959. The resulting solution was stirred in the absence of light for about 2 hours. The solution was then degassed and poured into a Petri dish. The solvent was evaporated off at room temperature. The ionomer was then crosslinked by two irradiations lasting 30 seconds each, with an interval of one minute between the two irradiations, using a UV lamp. The crosslinked ionomer I.sup.3 or I.sup.3 obtained was dried under vacuum at about 70 C. for at least 72 hours and stored in a glovebox.

Example 9

Preparation of a Cation-Conducting Ionomer I.SUP.4 in Accordance with the Second Subject of the Invention

(102) The synthetic scheme for obtaining the ionomer I.sup.4 is as follows:

(103) ##STR00031##

(104) 0.075 g of NaH (2.45 mmol, 2.3 equivalents) was placed in a three-necked round-bottomed flask under an argon atmosphere. A solution of 1.285 g of polyethylene glycol of molar mass 1000 g/mol (PEG 1000, n=22.7) (1.285 mmol, 1 equivalent) in 4 ml of diglyme was prepared in another flask. 3 ml of diglyme were then added to the flask containing the NaH and the resulting solution was added slowly to the solution containing the PEG 1000. The resulting reaction medium was heated at about 65 C. for 3 hours 30 minutes under an argon atmosphere.

(105) A solution containing 0.725 g of the monomer M.sup.2 as prepared in Example 2 (1.287 mmol, 1 equivalent) in 3 ml of diglyme was prepared in another flask and the solution was added slowly to the reaction medium. The resulting reaction medium was heated at about 140 C. for 24 hours. It was then cooled to room temperature and precipitated from pentane to give a solid containing the ionomer I.sup.4. The solid was filtered off and then dissolved in acetonitrile. The solution obtained was filtered so as to remove the inorganic salts. The filtrate was evaporated from a rotavapor so as to obtain the ionomer I.sup.4 in the form of a viscous liquid. This liquid was dried under vacuum at 100 C. for 48 hours (yield of ionomer I.sup.4 of about 62%).

(106) The ionomer I.sup.4 was characterized by fluorine and proton NMR:

(107) .sup.1H NMR: (ppm, acetone-d.sub.6)=6.83 (s, 2H, H.sub.3); 6.79 (s, 1H, H.sub.1); 4.21 (t, 4H, H.sub.10); 3.83 (t, 4H, H.sub.11); 3.60 (s, 90H, H.sub.12, O(CH.sub.2CH.sub.2O)).

(108) .sup.19F NMR: (ppm, acetone-d.sub.6)=79.65 (s, 3F, F.sub.9); 82.05 (s, 2F, F.sub.6); 87.74 (s, 2F, F.sub.7); 113.85 (s, 2F, F.sub.5); 117.20 (s, 2F, F.sub.8).

Example 10

Preparation of Cation-Conducting Ionomers I.SUP.5 and I.SUP.6 in Accordance with the Second Subject of the Invention

(109) The synthetic scheme for obtaining the ionomers I.sup.5 and I.sup.6 is as follows:

(110) ##STR00032##

(111) 0.075 g of NaH (2.45 mmol, 2.3 equivalents) was placed in a three-necked round-bottom flask under an argon atmosphere. A solution of 1.285 g of polyethylene glycol of molar mass 1000 g/mol (PEG 1000, n=22.7) (1.285 mmol, 1 equivalent) in 4 ml of diglyme was prepared in another flask. 3 ml of diglyme were then added to the flask containing the NaH and the resulting solution was added slowly to the solution containing the PEG 1000. The resulting reaction medium was heated at about 65 C. for 3 hours 30 minutes under an argon atmosphere.

(112) A solution containing 0.725 g of the monomer M.sup.2 as prepared in Example 2 (1.287 mmol, 1 equivalent) in 3 ml of diglyme was prepared in another flask and the solution was added slowly to the reaction medium. The resulting reaction medium was heated at about 140 C. for 24 hours.

(113) The reaction medium was cooled to about 60 C. and 1 mmol of ground NaOH was added. The resulting reaction medium was stirred for about 2 hours. 0.213 mmol of 3-chloro-2-chloroprop-1-ene was then added and the resulting reaction medium was stirred for about 12 hours. The solid was filtered off and then dissolved in acetonitrile. The solution obtained was filtered so as to remove the inorganic salts. The filtrate was evaporated on a rotavapor so as to obtain the ionomer in the form of a viscous liquid. This liquid was dried under vacuum at 100 C. for 48 hours (yield of ionomer I.sup.5 of about 88%).

(114) The ionomer I.sup.5 was characterized by fluorine and proton NMR:

(115) .sup.1H NMR: (ppm, actone-d.sub.6)=6.82 (s, 2H, H.sub.3); 6.76 (s, 1H, H.sub.1); 5.16 (s, 2H, H.sub.15); 4.23 (s, 4H, H.sub.10); 4.00 (s, 4H, H.sub.13); 3.83 (s, 4H, H.sub.11); 3.60 (s, 90H, H.sub.12, O(CH.sub.2CH.sub.2O)).

(116) .sup.19F NMR: (ppm, acetone-d.sub.6)=79.77 (s, 3F, F.sub.9); 82.14 (s, 2F, F.sub.6); 87.78 (s, 2F, F.sub.7); 113.93 (s, 2F, F.sub.5); 117.30 (s, 2F, F.sub.8).

(117) The ionomer I.sup.5 was then crosslinked according to the protocol of Example 8.

Example 11

Preparation of Electrolytic Compositions in Accordance with the Third Subject of the Invention

(118) Several electrolytic compositions were analysed by differential scanning calorimetry:

(119) an electrolytic composition C.sup.3 constituted of the ionomer I.sup.3 of Example 8,

(120) an electrolytic composition C.sup.3 constituted of the ionomer I.sup.3 of Example 8, and

(121) an electrolytic composition C.sup.3-A constituted of 90% by mass of the ionomer I.sup.4 of Example 8 and 10% by mass of cellulose nanofibres functionalized with sodium sulfonate groups Na.sup.+SO.sub.3.sup. (NCC).

(122) The NCCs were provided by the company FP Innovation, Canada. They are obtained from hardwood.

(123) The electrolytic composition C.sup.3-A was prepared in the following manner:

(124) 4 g of NCC were dispersed in 100 ml of distilled water in a container. The resulting dispersion was subjected to 4 cycles of 5 minutes of homogenization using a disperser, by imposing a speed of 13 000 rpm, especially with a machine sold under the trade name IKA Ultra-Turrax. The resulting dispersion was then subjected to ultrasonication using an ultrasound probe sold under the trade name VCX130 by the company Sonics & Materials, Inc., dipped directly into the dispersion. The duration of the ultrasonication cycle was about 15 minutes, with a pulse whose intensity was 6 out of 9. The container containing the dispersion was placed in a cold bath to prevent heating of said dispersion. Typically, to achieve homogeneous dispersion, about ten ultrasonication cycles were necessary for the NCCs used.

(125) 0.9 g of ionomer I.sup.2 was dissolved in 10 ml of water containing 0.02 g of Irgacure 2959. 2.5 ml (i.e. 0.1 g of NCC) of the dispersion of NCC in water as prepared previously were added to the resulting solution. The resulting dispersion was stirred in the absence of light for about 2 hours. The dispersion was then degassed and poured into a Petri dish. The solvent was evaporated off at room temperature. The ionomer was then crosslinked by two irradiations lasting 30 seconds each, with an interval of one minute between the two irradiations, using a UV lamp. The electrolytic composition C.sup.3-A obtained was dried under vacuum at about 70 C. for at least 72 hours and stored in a glovebox.

(126) The DSC analyses are given in FIG. 1 (heat flow as a function of the temperature) and showed that the ionomers of compositions C.sup.3 (curve with the crosses), C.sup.3 (curve with the triangles) and C.sup.3-A (curve with the circles) were entirely amorphous since no melting peak was observed. Moreover, the glass transition temperatures T.sub.g of said ionomers were of the same order of magnitude as those obtained with an electrolyte of the prior art POE/LiTFSI (i.e. about 34 to 40 C.).

(127) Ion conductivity tests between 20 and 90 C. are reported in FIG. 2 and showed that at 50 C., the conductivity of composition C.sup.3 (filled diamonds) and of composition C.sup.3 (filled squares) was about 110.sup.5 S.Math.cm.sup.1. That of composition C.sup.3-A (filled triangles) was slightly smaller, but the mechanical stability of said composition C.sup.3-A was improved due to the presence of the functionalized cellulose nanofibres NCC.

(128) The NCCs also make it possible to reduce the dendritic growth.

(129) Tests of ion conductivity between 20 and 90 C. were also performed on electrolytic compositions C.sup.1 and C.sup.4, respectively constituted of the ionomer I.sup.1 and the ionomer I.sup.4, and are reported in FIG. 3.

(130) They showed that at 50 C., the conductivity of C.sup.4 (filled squares) is 410.sup.5 S.Math.cm.sup.1 and that of C.sup.1 (filled circles) is 1.810.sup.5 S.Math.cm.sup.1.

(131) Moreover, the ion transport numbers of the crosslinked ionomers I.sup.3, I.sup.3, I.sup.6 (i.e. of formula similar to that of I.sup.6 but in the lithium form instead of the sodium form) and I.sup.6 were 1.