Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M6/00—Primary cells; Manufacture thereof
  • H01M6/14—Cells with non-aqueous electrolyte
  • H01M6/18—Cells with non-aqueous electrolyte with solid electrolyte
  • H01M6/181—Cells with non-aqueous electrolyte with solid electrolyte with polymeric electrolytes
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F283/00—Macromolecular compounds obtained by polymerising monomers on to polymers provided for in subclass C08G
  • C08F283/06—Macromolecular compounds obtained by polymerising monomers on to polymers provided for in subclass C08G on to polyethers, polyoxymethylenes or polyacetals
  • C08F283/065—Macromolecular compounds obtained by polymerising monomers on to polymers provided for in subclass C08G on to polyethers, polyoxymethylenes or polyacetals on to unsaturated polyethers, polyoxymethylenes or polyacetals
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G4/00—Condensation polymers of aldehydes or ketones with polyalcohols; Addition polymers of heterocyclic oxygen compounds containing in the ring at least once the grouping —O—C—O—
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G65/00—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule
  • C08G65/02—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule from cyclic ethers by opening of the heterocyclic ring
  • C08G65/04—Macromolecular compounds obtained by reactions forming an ether link in the main chain of the macromolecule from cyclic ethers by opening of the heterocyclic ring from cyclic ethers only
  • C08G65/06—Cyclic ethers having no atoms other than carbon and hydrogen outside the ring

Definitions

• Oxirane and dioxoiane copolymers their preparation process and ionically conductive materials containing them.
• the present invention relates to copolymers, their preparation process and their use for the preparation of ionically conductive materials.
• Polymer electrolytes obtained by disso ⁇ lution of a salt in a solvating polymer comprising hetero atoms are known.
• Such electrolytes the solvent of which is a polyethylene oxide or an ethylene oxide copolymer, are described, for example, in EP-A-13199 (M. Armand, M. Duclot).
• These polymer electrolytes have many applications, in particular in the field of electrochemical generators, light modulation systems (M. Armand et al, EP-87401555), sensors, for example for selective membranes or reference (A. Hammou et al, FR-86.09602).
• Polyethylene oxide is a semi-crystalline polymer which forms with salts stoichiometric complexes.
• the amorphous conductive phases of these complexes only exist above a eutectic temperature generally between 40 ° C and 65 "C depending on the nature of the complexed salts.
• Good conductivities at ordinary temperature are only obtained with macromolecular systems with little or no crystallinity. Numerous studies have been carried out to improve the conduction properties of these materials. They have resulted, for example, in the formation of oxide-based copolymers.
• ethylene M. Armand et al, FR-83.09886
• Dioxoiane homopolymers are also known which are very crystalline and which have melting temperatures close to 55 "C.
• the conductivity of the poly-dioxolane / salt complexes at temperatures below 25 ° C. is therefore poor.
• it is difficult to obtain by cationic polymerization of dioxoiane high-mass polymers the mechanical properties of the electrolytes prepared from these homopolymers are therefore poor at temperatures above 80 ° C.
• the purpose of the present invention is to provide materials with ion conduction comprising a solid polymer electrolyte and having both good conductivity and good mechanical strength.
• the present invention relates to a family of crosslinkable copolymers having a low crystallinity.
• the invention also relates to a process for the preparation of said copolymers.
• the subject of the invention is materials with ionic conduction, the solvent of which consists essentially of the abovementioned copolymer.
• a copolymer according to the invention consists of monomer units corresponding to the formula -CH 2 -0-CHR-CH 2 -0- (I) and monomer units corresponding to the formula -CH 2 -CHR'-0- ( II) in which:
• - R represents a hydrogen atom, a linear or branched al yl radical containing from 1 to 8 carbon atoms or a CH 3 (-0-CH 2 -CH 2 ) n -0-CH 2 - radical, in which 1 ⁇ n ⁇ 10; - R 'represents an aliphatic radical having an unsaturation which can be polymerized by the radical route and which is inert under the cationic polymerization conditions.
• radicals R, H and CH 3 are very particularly preferred.
• the monomer units (I) and the monomer units (II) constituting a copolymer of the present invention are derived respectively from a dioxoiane and an oxirane.
• the ratio p / (p + m) is between approximately 3% and approximately 30%, more particularly between approximately 5% and approximately 10%, p representing the number of monomer units (II) and m representing the number of monomer units (I) constituting a copolymer of the present invention.
• the copolymer thus obtained has long blocks (40 to 60 monomer units) of polydioxolane and short blocks of oxirane. However, the overall distribution of the monomer units exhibits a statistical trend.
• copolymers of the present invention can be obtained by cationic polymerization of oxirane
• BF3 O2H5
• C5H5COX 1 C6H5CH2 1 in which X 1 represents SbF 6 , PF 6 , AsF 6 , BF, SbF 6 or CF 3 SO 3 , SbFg being particularly preferred, or pCl- c 6 H 4 N 2 ⁇ 1 ' ⁇ l representing PF 6 or BF 4 .
• the cationic polymerization can be carried out in bulk, the dioxoiane then serving simultaneously as solvent and comonomer.
• the cationic polymerization can also be carried out in a concentrated solution of monomers in an aprotic solvent. Among these solvents, mention may be made of dichloromethane and nitromethane.
• the addition of the oxirane can be carried out at once, several times discontinuously, or continuously throughout the duration of the polymerization. The last two modes of addition are preferred because the copolymers obtained give, after crosslinking, a higher rate of insolubles.
• the copolymers according to the present invention in which the p / (p + m) ratio is between 3% and 30%, are particularly useful for the preparation of materials with ionic conduction.
• the ion-conducting materials of the present invention essentially consist of an easily dissociable salt and a polymer obtained by crosslinking of a copolymer according to the present invention, preferably a copolymer in which the ratio p / (p + m) is between approximately 3% and approximately 30%, more particularly between approximately 5% and approximately 10%.
• the salt introduced into the copolymer before crosslinking or in the crosslinked polymer is chosen from the salts usually used for solid materials with ionic conduction.
• X representing an anion with delocalized electronic charge, for example Br ⁇ , ClO ⁇ -, AsF 6 ⁇ , R F S0 3 ⁇ , (R F S0 2 ) 2 N ⁇ , (R F S ⁇ 2 ) 3 C ⁇ , R F representing a perfluoroalkyl or perfluoroaryl group.
• the salt can also be chosen from the salts corresponding to the formula (l / nM) + [(RpS0 2 ) 2CY] "in which Y represents an electron-attracting group chosen from -C ⁇ N and the groups RZ- in which Z represents a carbonyl group, a sulfonyl group or a phosphonyl group and R represents a monovalent organic group, M represents a metal having the valence n or an organic group which may exist in cationic form, Rp represents a perfluoroalkyl or perfluoroaryl group.
• Such compounds can be prepared by reacting a compound (1 / nM) + [(RpS0 2 ) CH] "with a compound YX in the presence of a nucleotic aprotic base Nu, X representing a halogen or a pseudo-halogen.
• a compound YX in the presence of a nucleotic aprotic base Nu, X representing a halogen or a pseudo-halogen.
• the lithium salts are particularly preferred, more especially (CF 3 S0 2 ) 2 N ⁇ L i + and (CF3SO2) 3C ⁇ Li + . Mixtures of salts can be used.
• the ionically conductive materials of the present invention may also contain additives usually used in ionically conductive materials such as plasticizers or stabilizers, depending on the final properties sought.
• an ionically conductive material is obtained by dissolving the copolymer, the salt and the initiator in a common solvent.
• the amount of initiator used is advantageously from 2 to 5% by weight relative to the copolymer.
• the solvent is chosen from volatile solvents; by way of example of such a solvent, mention may be made of acetonitrile, tetrahydrofuran and acetone.
• the viscous solution obtained is degassed, then spread on an appropriate support, for example a PTFE plate. After evaporation of the solvent, the film obtained is brought to a temperature between 70 ° C. and 120 ° C. depending on the initiator used, for 4 hours.
• L 1 cross-linking initiator can be chosen by example among benzoyl peroxide, azobis isobutyronitrile (AIBN) or dicumylperoxide (Dicup). Benzoyl peroxide is particularly preferred.
• the crosslinking of the copolymer in solution in a solvent similar to that described above is carried out first, in the absence of salt, and a membrane is produced in the same manner as above. is lying.
• the salt is then introduced into the membrane as follows: a very concentrated solution of the salt in acetonitrile is produced, it is made to absorb by the membrane, then the solvent is evaporated.
• the amount of salt introduced is determined by the difference between the initial weight of the membrane and its final weight.
• the crosslinking of a copolymer of the present invention is carried out in solution in an appropriate solvent using a radical polymerization initiator, in the presence of a monomer carrying an ionic group and a group crosslinkable by radical route.
• a monomer carrying an ionic group and a group crosslinkable by radical route can be chosen from those which correspond to the general formula (1) ACFX 2 -S0 2 Z 2 in which:
• A represents one of the groups R 1 R 2 N-C0-, R 3 -0-CF 2 - or
• - Z 2 represents an ionic group
• - X 2 represents F, Cl, H or R F ;
• radicals R 1 , R 2 and R 3 which are identical or different, are chosen from non-perfluorinated organic radicals comprising a function which can be polymerized by the radical route;
• R F is chosen from perfluoroalkyl radicals and perfluoroaryl radicals.
• the ionic group Z 2 is advantageously chosen from l / mM ⁇ -O] " , l / mM" * [- NS0 2 Q] " , l / mM ⁇ f-CH (S0Q)] ⁇ and l / mM m + [- C (S0 2 Q) 2 ] ⁇ , Q representing -R F or -CFX-A and M "representing an ion of a metal having the valence m, chosen from alkali metals, alkaline earth metals, transition metals and rare earths, or ammonium, amidinium or guanidinium ions.
• the monomers (1) can be prepared by reaction of an acid fluoride sulfonyl acetic F-COCFX-S0 2 F with an amine R 1 R 2 NH in the presence of a base.
• the monomers (1) can be obtained from the sulfonylacetic acid fluoride by a three-step process: reaction of the sulfonylacetic acid fluoride with a fluoride M 'F; bringing the perfluoroalkoxide obtained into contact with a reagent R 3 Y to obtain the compound R 3 0-CF-CFX-SO 2 F; reaction of this compound with the appropriate reagent to replace the fluorine of the SO 2 F group with an ionic group chosen from l / mM ⁇ CO] -, l / mM + [-NS0 2 R F ] ⁇ , 1 / mM "[- CH (S0 2 R F )] " or
• the monomers (1) are obtained from the sulfonylacetic acid fluoride by a three-step process.
• a first step the sulfonylacetic acid fluoride is treated with water, which causes hydrolysis followed by decarboxylation.
• the compound obtained has on the ⁇ carbon a proton having an acidic character allowing the formation of a carbion which gives rise, during a second step, to a nucleophilic substitution reaction in the presence of a base.
• the compound obtained is reacted with the appropriate reagent to replace the fluorine of the SO 2 F group with an ionic group.
• Such monomers are described in FR92.02027 deposited on February 21, 1992, to which reference will be made for more details.
• those which are monomers derived from perhalogenated sultones are particularly interesting.
• the ion conduction materials obtained, consisting of a crosslinked polymer and a salt, can be used as solid polymer electrolyte in an electrochemical cell. They are particularly useful for electrochemical generators, rechargeable or not. They are also useful in other electrochemical systems such as electrochromic systems, light modulation systems, for the development of selective membranes or reference membranes in membrane sensors.
• the present invention is illustrated by the following examples given by way of illustration but not limitation.
• EXAMPLE 1 37 g of dioxoiane were dissolved in dichloromethane so as to obtain a solution of 5 moles / liter. To this solution, maintained under argon at -20 ° C, was added 1.12 g of benzoyl hexafluoroanti onate in solution in dichloromethane (0.034 mol / liter), then 4.312 g of 1,2-epoxy-hexene -5 in the form of a 0.44 mol / liter solution in dichloromethane, in 0.2 cm 3 fractions every 20 min. The polymerization is considered to be complete after two hours.
• the copolymer obtained is purified by dissolution in tetrahydrofuran and precipitation in pentane.
• the precipitate is filtered, then dried under vacuum at 40 ° C.
• the conductivity is 2.10 -6 S / cm at 5 ° C, 4.10 "5 S / cm at 25 ° C and reaches 10 ⁇ 3 S / cm at 70 ° C.
• the range of electrochemical stability compared to lithium is 4.5 volts.
• EXAMPLE 5 An electrochemical generator was developed comprising a negative lithium electrode, an ionically conductive material according to the invention as an electrolyte, and a composite positive electrode.
• the negative electrode consisted of a layer of lithium having a thickness of 50 ⁇ m deposited on a polypropylene film of 8 ⁇ m metallized by a layer of 100 nm of nickel.
• the electrolyte was obtained in the following manner. A copolymer analogous to that used in Example 4 was brought to 40 ° C., and then added thereto without using a solvent 3% by weight of benzoyl peroxide and 35% by weight of salt (CF3SO2) 2 NIj i le O / Li atomic ratio being 14. The mixture was spread on a 30 ⁇ m polypropylene film.
• the positive electrode used was constituted by a composite material containing 45% by volume of lithium manganite of spinel structure LiMn 2 0 4 in grains of approximately 8 ⁇ , 5% by volume of acetylene black and 50% by volume d 'a material obtained by incorporating the salt (CF3S ⁇ 2) 2 NIj i in a copolymer similar to that used for the electrolyte but not crosslinked, in an amount of 35% by weight of salt relative to the copolymer.
• the various constituents were mixed at 50 ° C., without the addition of solvent, and the mixture was then spread on a current collector similar to that of the negative electrode.

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• Macromonomer-Based Addition Polymer (AREA)
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• 1992
  • 1992-07-15 FR FR9208716A patent/FR2693731B1/fr not_active Expired - Fee Related
• 1993
  • 1993-07-07 CA CA002118946A patent/CA2118946A1/fr not_active Abandoned
  • 1993-07-07 JP JP6504194A patent/JPH06511285A/ja active Pending
  • 1993-07-07 EP EP93914825A patent/EP0603370A1/de not_active Withdrawn
  • 1993-07-07 WO PCT/FR1993/000701 patent/WO1994002534A1/fr not_active Ceased
  • 1993-07-07 US US08/193,134 patent/US5552510A/en not_active Expired - Lifetime

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