Flexible Polymer Electrolyte

Abstract

The present invention relates to hybrid organic / inorganic composite materials based on certain fluoropolymers, polymer electrolytes obtained therefrom, and the use of said polymer electrolytes in electrochemical devices.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to European Patent Application No. 18215077.1, filed December 21, 2018, the entire contents of which are incorporated herein by reference for all purposes.

[0002] The present invention relates to hybrid organic / inorganic composite materials based on certain fluoropolymers, polymer electrolytes obtained therefrom, and the use of said polymer electrolytes in electrochemical devices. [Background technology]

[0003] Hybridization of organic and inorganic compounds at the nanometer scale is an important and expansive method for creating novel materials. Organic-inorganic polymer hybrids, in which organic polymers are dispersed in inorganic solids at the nano- or molecular level, have attracted great scientific, technological, and industrial attention due to their unique properties.

[0004] The most useful and important method for creating organic-inorganic polymer hybrids is the sol-gel method using metal alkoxides. By appropriately controlling the reaction conditions for the hydrolysis and polycondensation of metal alkoxides, especially alkoxysilanes (e.g., tetramethoxysilane (TMOS) or tetraethoxysilane (TEOS)), in the presence of preformed organic polymers, it is possible to obtain hybrids with improved properties compared to the parent compounds.

[0005] Hybrids made by the sol-gel technique starting from fluoropolymers, in particular from vinylidene fluoride polymers (PVDF), are known in the art.

[0006] Fluoropolymer hybrid organic / inorganic composites produced from sol-gel techniques, especially those produced starting from PVDF, are particularly suitable for use in the fabrication of membranes for secondary batteries.

[0007] WO 2013 / 160240 (S 2012 / 023) discloses fluoropolymer films comprising fluoropolymer hybrid organic / inorganic composites and their use in the preparation of membranes for electrochemical applications, more particularly as separators in lithium ion batteries.

[0008] In some modern applications, such as flexible batteries, the battery components must be flexed multiple times during their life in a given structure or device.

[0009] For application as membranes in metal-ion secondary batteries, fluoropolymer hybrid organic / inorganic composite films must remain intact despite high temperature peaks during battery operation, so high melting points and flexible composites are desired to avoid damage to these battery components.

[0010] Furthermore, a more flexible polymer electrolyte tends to improve contact with the electrodes, avoiding zones of no contact between the separator and the electrodes, thus lowering the interfacial resistance.

[0011] In addition, considering the current significant increase in the use of batteries in electric vehicles to avoid CO2 emissions in the atmosphere of our cities, manufacturing said batteries in more environmentally friendly and sustainable processes has become very important these days.

[0012] Therefore, there is a need for fluoropolymer hybrid organic / inorganic composite materials characterized by high thermal stability and great flexibility that can be sustainably produced, thereby requiring little energy and non-toxic solvents. Summary of the Invention

[0013] The Applicant has now surprisingly found that, starting from certain novel vinylidene fluoride copolymers, it is possible to prepare hybrid organic / inorganic composite materials characterized by high heat resistance and great flexibility, which can be produced by a process that avoids the use of polluting organic solvents.

[0014] Therefore, a first object of the present invention is a method for producing a fluoropolymer hybrid organic / inorganic composite material containing inorganic domains, said method comprising: (i) - (a) Repeating units derived from vinylidene fluoride (VDF); (b) Repeating units derived from chlorotrifluoroethylene (CTFE); (c) Formula (I): TIFF0007811475000001.tif40161 (wherein R1, R2, and R3, which are equal to or different from each other, are independently a hydrogen atom or a C1-C3 hydrocarbon group; R X is a C1-C5 hydrocarbon moiety containing at least one hydroxyl group) Repeating units derived from at least one hydrophilic (meth)acrylic monomer [monomer (MA)] of the formula: (d) Repeating units derived from one or more fluorinated comonomers (F) different from VDF and CTFE at least one semi-crystalline vinylidene fluoride (VDF) copolymer [polymer (A)] comprising: a semi-crystalline vinylidene fluoride (VDF) copolymer [polymer (A)], in which the total amount of repeating units b) is 6% by weight to 25% by weight, based on the total weight of repeating units of polymer (A), and the total amount of repeating units d) is 0.5% by weight to 4% by weight, based on the total weight of repeating units of polymer (A); -Formula (II): X 4-m AY m (II) (wherein m is an integer of 1 to 4, A is a metal selected from the group consisting of Si, Ti and Zr, Y is a hydrolyzable group, and X is a hydrocarbon group optionally containing one or more functional groups). and at least one compound (M) of the formula: preparing a mixture of: (ii) Pendant-Y m-1 AX 4-m In order to obtain a graft polymer containing the groups (m, Y, A, and X have the same meanings as detailed above), the R X reacting at least a portion of the hydroxyl groups of with at least a portion of said compound (M); (iii) Compound (M) and / or pendant-Y, as detailed above m-1 AX 4-m hydrolyzing and / or polycondensing the groups to obtain a fluoropolymer hybrid organic / inorganic composite containing inorganic domains. Includes.

[0015] In a second object, the present invention provides a fluoropolymer hybrid organic / inorganic composite material comprising inorganic domains obtainable by the method of the present invention.

[0016] Surprisingly, we have found that when the preparation of a fluoropolymer hybrid organic / inorganic composite is carried out in the presence of an electrolyte solution comprising a liquid medium and at least one electrolyte salt, a free-standing polymer electrolyte is obtained, which has excellent flexibility, ionic conductivity, and thermal stability.

[0017] Therefore, a third object of the present invention is a polymer electrolyte based on a fluoropolymer hybrid organic / inorganic composite material containing inorganic domains, said polymer electrolyte comprising: (I) - (a) Repeating units derived from vinylidene fluoride (VDF); (b) Repeating units derived from chlorotrifluoroethylene (CTFE); (c) Formula (I): TIFF0007811475000002.tif41161 (wherein R1, R2, and R3, which are equal to or different from each other, are independently a hydrogen atom or a C1-C3 hydrocarbon group; R X is a C1-C5 hydrocarbon moiety optionally containing at least one hydroxyl group a repeating unit derived from at least one hydrophilic (meth)acrylic monomer [monomer (MA)] of the formula: (d) Repeating units derived from one or more fluorinated comonomers (F) different from VDF and CTFE at least one semi-crystalline vinylidene fluoride (VDF) copolymer [polymer (A)] comprising: a semi-crystalline vinylidene fluoride (VDF) copolymer [polymer (A)], in which the total amount of repeating units b) is 6% by weight to 20% by weight, based on the total weight of repeating units of polymer (A), and the total amount of repeating units d) is 0.5% by weight to 4% by weight, based on the total weight of repeating units of polymer (A); -Formula (II): X 4-m AY m (II) (wherein m is an integer of 1 to 4, A is a metal selected from the group consisting of Si, Ti and Zr, Y is a hydrolyzable group, and X is a hydrocarbon group optionally containing one or more functional groups). and at least one compound (M) of the formula: an electrolyte solution (ES) comprising at least one metal salt [metal salt (MS)] and a liquid medium [medium (L)], preparing a mixture of: (II) Pendant-Y m-1 AX 4-m In order to obtain a graft polymer containing the groups (m, Y, A, and X have the same meanings as detailed above), the R X reacting at least a portion of the hydroxyl groups of the group with at least a portion of said compound (M); (III) Compound (M) and / or pendant-Ym-1AX, as detailed above. 4-mHydrolysis and / or polycondensation of the groups to obtain a polymer electrolyte based on a fluoropolymer hybrid organic / inorganic composite containing inorganic domains entrapped in the electrolyte solution (ES). The compound is obtained by a method comprising:

[0018] The polymer electrolyte of the present invention can be suitably used for the production of a polymer electrolyte membrane.

[0019] Therefore, in a further object, the present invention provides a method for producing a polymer electrolyte membrane, comprising processing a polymer electrolyte as defined above by compression molding or extrusion techniques.

[0020] The polymer (A) as defined above used for the preparation of the fluoropolymer hybrid organic / inorganic composite material of the present invention is novel and therefore constitutes another object of the present invention.

[0021] The present invention further relates to an electrochemical device comprising a polymer electrolyte membrane as defined above. DETAILED DESCRIPTION OF THE INVENTION

[0022] The term "repeating unit derived from vinylidene fluoride" (also commonly referred to as vinylidene difluoride 1,1-difluoroethylene, VDF) is intended to indicate a repeating unit of formula CF2=CH2.

[0023] The term "semi-crystalline" is intended to denote a vinylidene fluoride (VDF) polymer having a detectable melting point. Semi-crystalline VDF polymers are generally understood to have a heat of fusion of advantageously at least 0.4 J / g, preferably at least 0.5 J / g, more preferably at least 1 J / g, measured according to ASTM D 3418.

[0024] The term "repeating units derived from chlorotrifluoroethylene" is intended to indicate repeating units of formula CF2=CFCl.

[0025] The polymer (A) according to the invention has in particular an intrinsic viscosity of at most 0.50 l / g, preferably at most 0.45 l / g, more preferably at most 0.25 l / g and even more preferably at most 0.20 l / g.

[0026] The polymer (A) of the invention has in particular an intrinsic viscosity of at least 0.05 l / g, preferably at least 0.08 l / g, more preferably at least 0.15 l / g and even more preferably at least 0.10 l / g.

[0027] The intrinsic viscosity of polymer (A) is typically measured in N,N-dimethylformamide at 25°C.

[0028] The term "at least one hydrophilic (meth)acrylic monomer (MA)" is understood to mean that the polymer (A) may comprise repeat units derived from one or more hydrophilic (meth)acrylic monomers (MA) as defined above. In the remainder of the specification, the expressions "hydrophilic (meth)acrylic monomers (MA)" and "monomers (MA)" are understood for the purposes of the present invention to refer both to the plural and to the singular, i.e. to one or more of both hydrophilic (meth)acrylic monomers (MA).

[0029] Non-limiting examples of hydrophilic (meth)acrylic monomers (MA) of formula (I) include, among others: - hydroxyethyl (meth)acrylate (HEA), - 2-hydroxypropyl acrylate (HPA), - hydroxyethylhexyl (meth)acrylate, and mixtures thereof.

[0030] More preferably, the at least one hydrophilic (meth)acrylic monomer (MA) is hydroxyethyl acrylate (HEA).

[0031] In a preferred embodiment of the present invention, the repeating units derived from the hydrophilic (meth)acrylic monomer (MA) of formula (I) are contained in the polymer (A) in an amount of 0.1 to 3% by weight, preferably 0.3 to 2% by weight, more preferably 0.4 to 1.5% by weight, based on the total weight of the repeating units of the polymer (A).

[0032] The term "fluorinated comonomer (F)" is intended herein to mean an ethylenically unsaturated comonomer containing at least one fluorine atom.

[0033] Non-limiting examples of suitable fluorinated comonomers (F) include, in particular: (a) C2-C8 fluoro- and / or perfluoroolefins, such as tetrafluoroethylene (TFE), hexafluoropropylene (HFP), pentafluoropropylene, and hexafluoroisobutylene; (b) C2-C8 hydrogenated monofluoroolefins, such as 1,2-difluoroethylene and trifluoroethylene; (c)Formula CH2=CH-R f0 (In the formula, R f0 is a C1-C6 perfluoroalkyl group); (d) Formula CF2=CFOR f1 (per)fluoroalkyl vinyl ethers (wherein R f1 is a perfluoroalkyl group, -CF3 (perfluoromethyl vinyl ether (PMVE)), -C2F5 (perfluoroethyl vinyl ether (PEVE)), -C3F7 (perfluoropropyl vinyl ether (PPVE)), -C4F9, or -C5F 11 (which is the base), (e) Chloro- and / or bromo- and / or iodo-C2 to C6 fluoroolefins.

[0034] The fluorinated comonomer (F) is preferably HFP or PMVE.

[0035] The repeating units derived from the fluorinated comonomer (F) are preferably contained in the polymer (A) in an amount of 0.7 to 2.0% by weight based on the total weight of the repeating units of the polymer (A).

[0036] In a more preferred embodiment of the present invention, the polymer (A) is - 8 to 20% by weight of repeating units derived from CTFE monomers; - 0.4 to 1.5% by weight of repeat units derived from hydrophilic (meth)acrylic monomers (MA) of formula (I), - 0.7 to 2.0 wt. % of repeating units derived from a comonomer (F); and preferably consisting of These weight percentages are based on the total weight of repeating units of polymer (A).

[0037] Determination of the weight (average molar) percentages of repeat units of the monomers CTFE, monomer (MA), fluorinated comonomer (F), and VDF in polymer (A) can be done by any suitable method, with NMR being preferred.

[0038] In a preferred embodiment of the present invention, polymer (A) is a VDF-CTFE-HEA-HFP tetrapolymer. Preferably, polymer (A) of said preferred embodiment has an intrinsic viscosity of at least 0.10 l / g and a second melting temperature (T) of at least 130°C, preferably at least 145°C, more preferably at least 150°C. 2f )

[0039] Second melting temperature (T 2f ) is typically measured by differential scanning calorimetry (DSC) according to the ASTM D 3418 standard method.

[0040] The polymer (A) according to the invention is typically obtained by polymerizing VDF monomer, at least one hydrogenated (meth)acrylic monomer (MA), CTFE monomer and at least one fluorinated comonomer (F), either in suspension, for example according to the procedure described in WO 2008 / 129041, or in emulsion, typically carried out as described in the art (see, for example, US Pat. Nos. 4,016,345, 4,725,644 and 6,479,591).

[0041] The polymerization reaction is usually carried out at temperatures between 25°C and 150°C and pressures up to 130 bar.

[0042] The polymer (A) is typically supplied in the form of a powder.

[0043] Polymer (A) can optionally be further extruded to provide polymer (A) in the form of pellets.

[0044] formula 4-m AY m The metal compound (M) [compound (M)] may contain one or more functional groups on either the group X or the group Y, preferably on at least one group X.

[0045] If compound (M) contains at least one functional group, it will be referred to as functional compound (M); if neither group X nor group Y contains a functional group, compound (M) will be referred to as non-functional compound (M).

[0046] The functional compound (M) can advantageously provide the fluoropolymer hybrid organic / inorganic composite with functional groups, which further modify the chemistry and properties of the hybrid composite over the original polymer (A) and the original inorganic phase.

[0047] Non-limiting examples of functional groups include epoxy groups, carboxylic acid groups (in the form of their acids, esters, amides, anhydrides, salts or halides), sulfonic acid groups (in the form of their acids, esters, salts or halides), hydroxyl groups, phosphoric acid groups (in the form of their acids, esters, salts or halides), thiol groups, amine groups, quaternary ammonium groups, ethylenically unsaturated groups (such as vinyl groups), cyano groups, urea groups, organosilane groups, and aromatic groups.

[0048] For the purpose of obtaining polymer electrolytes based on functionalized fluoropolymer hybrid organic / inorganic composites, the compounds of formula X 4-m AY m It is generally preferred that any of the groups X of compound (M) contains one or more functional groups, and m is an integer from 1 to 3, so that advantageously each A atom is bonded to a group that contains a functional group, even after complete hydrolysis and / or polycondensation in step (i) of the process.

[0049] Preferably, X in the compound (M) is C1 to C 18 More preferably, X in compound (M) is selected from the group consisting of C1 to C6 hydrocarbon groups, optionally containing one or more functional groups. 12 A hydrocarbon group, optionally containing one or more functional groups.

[0050] If the aim is to prepare polymer electrolytes based on fluoropolymer hybrid organic / inorganic composites capable of exhibiting functional behavior in terms of hydrophilicity or ion conductivity, the functional groups of compound (M) will preferably be selected from carboxylic acid groups (in their acid, anhydride, salt or halide form), sulfonic acid groups (in their acid, salt or halide form), phosphoric acid groups (in their acid, salt or halide form), amine groups and quaternary ammonium groups; most preferably from carboxylic acid groups (in their acid, anhydride, salt or halide form) and sulfonic acid groups (in their acid, salt or halide form).

[0051] The choice of hydrolyzable group Y of compound (M) is not particularly limited, provided that it is capable of forming an -OA≡ bond under appropriate conditions; said hydrolyzable group may in particular be a halogen (especially a chlorine atom), a hydrocarbyl group, an acryloxy group, or a hydroxyl group.

[0052] Examples of functional compounds (M) are in particular vinyltriethoxysilane, vinyltrimethoxysilane, vinyltrismethoxyethoxysilane of formula CH2=CHSi(OC2H4OCH3)3, vinyltrismethoxyethoxysilane of formula: TIFF0007811475000003.tif19161 2-(3,4-epoxycyclohexylethyltrimethoxysilane), formula: TIFF0007811475000004.tif23161 Glycidoxypropylmethyldiethoxysilane, formula: TIFF0007811475000005.tif16161 Glycidoxypropyltrimethoxysilane, formula: TIFF0007811475000006.tif17161 methacryloxypropyltrimethoxysilane, formula: TIFF0007811475000007.tif18161 aminoethylaminopropylmethyldimethoxysilane, formula: H2NC2H4NHC3H6Si(OCH3)3 aminoethylaminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-phenylaminopropyltrimethoxysilane, 3-chloroisobutyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, n-(3-acryloxy-2-hydroxypropyl)-3-aminopropyltriethoxysilane, (3-acryloxypropyl)dimethylmethoxysilane, (3-acryloxypropyl)methyldichlorosilane, (3-acryloxypropyl)methyldimethoxysilane, 3-(n-allylamino)propyltrimethoxysilane, 2-(4-chlorosulfonylphenyl)ethyltrimethoxysilane, 2-(4-chlorosulfonylphenyl)ethyltrichlorosilane, carboxyethylsilanetriol, and sodium salts thereof of the formula: TIFF0007811475000008.tif20161 triethoxysilylpropylmaleamic acid, 3-(trihydroxysilyl)-1-propane-sulfonic acid of formula HOSO2-CH2CH2CH2-Si(OH)3, N-(trimethoxysilylpropyl)ethylene-diaminetriacetic acid, and its sodium salt, of formula: TIFF0007811475000009.tif31161 3-(triethoxysilyl)propylsuccinic anhydride, acetamidopropyltrimethoxysilane of formula H3C-C(O)NH-CH2CH2CH2-Si(OCH3)3, Ti(A) X (OR) Y where A is an amine-substituted alkoxy group, such as OCH2CH2NH2, R is an alkyl group, and x and y are integers such that x+y=4.

[0053] Examples of non-functional compounds (M) are in particular triethoxysilane, trimethoxysilane, tetramethyl titanate, tetraethyl titanate, tetra-n-propyl titanate, tetraisopropyl titanate, tetra-n-butyl titanate, tetra-isobutyl titanate, tetra-tert-butyl titanate, tetra-n-pentyl titanate, tetra-n-hexyl titanate, tetraisooctyl titanate, tetra-n-lauryl titanate, tetraethoxysilane ... tetra-n-butyl zirconate, tetra-sec-butyl zirconate, tetra-tert-butyl zirconate, tetra-n-pentyl zirconate, tetra-tert-pentyl zirconate, tetra-tert-hexyl zirconate, tetra-n-heptyl zirconate, tetra-n-octyl zirconate, and tetra-n-stearyl zirconate.

[0054] The process of the present invention can use a mixture of one or more functional compounds (M) and one or more non-functional compounds (M). Alternatively, the functional compounds (M) or the non-functional compounds (M) can be used separately.

[0055] The amount of compound (M) used in the process of the invention is such that the mixture of step (i) advantageously contains at least 0.1% by weight, preferably at least 1% by weight and more preferably at least 5% by weight of said compound (M), based on the total weight of polymer (A) and compound (M) in said mixture.

[0056] The amount of compound (M) used in the process of the invention is such that the mixture of step (i) advantageously contains at most 95% by weight, preferably at most 75% by weight, more preferably at most 55% by weight of said compound, based on the total weight of polymer (A) and compound (M) in said mixture.

[0057] The polymer (A) comprising repeating units derived from at least one monomer (MA) having formula (I) as defined above and the compound (M) can in particular be reacted in the melt phase.

[0058] A melt kneader such as an extruder, melt kneader or other device can be advantageously used for this purpose.

[0059] The polymer (A) and the compound (M) can also be reacted in particular in the liquid phase. When they are reacted in the liquid phase, the mixture of step (i) of the process of the invention can contain at least one organic solvent (S).

[0060] The choice of organic solvent (S) is not particularly limited as long as it is suitable for solubilizing the polymer (A) of the present invention at temperatures below 30°C.

[0061] The organic solvent (S) is typically selected from the group consisting of ketones, including lower ketones such as acetone and methyl ethyl ketone, and higher ketones such as isophorone, methyl isobutyl ketone (MIK), cyclohexanone, and diisobutyl ketone; amides such as N,N-dimethylformamide (DMF), N,N-dimethylacetamide, and tetramethylurea; polar aprotic solvents containing oxygen and / or nitrogen heteroatoms, such as dimethyl sulfoxide (DMSO), tetrahydrofuran (THF), and N-methyl-2-pyrrolidone (NMP); and organic phosphates such as trimethyl phosphate, triethyl phosphate, and mixtures thereof.

[0062] The selection of non-toxic solvents in the preparation of polymer compositions makes them particularly suitable for use in the manufacture of components for secondary batteries, such as those for portable devices or electric vehicles, a market that is constantly growing in recent years.

[0063] Avoiding the use of toxic and polluting solvents in the manufacture of secondary battery components can eliminate costs and avoid safety and environmental concerns associated with handling large amounts of such solvents.

[0064] Therefore, according to a preferred embodiment of the present invention, the organic solvent (S) is a non-toxic solvent, preferably a ketone.

[0065] Very good results have been obtained when the ketone is a straight chain aliphatic ketone, preferably acetone, having a normal boiling point below 120°C, preferably below 100°C, more preferably below 70°C.

[0066] When the polymer (A) and the metal compound (M) are reacted in the liquid phase, the mixing can be carried out at room temperature (about 25° C.) or upon heating.

[0067] According to one embodiment of the present invention, the mixture of step (i) of the method of the present invention may further comprise at least one inorganic filler (I).

[0068] The addition of such inorganic fillers (I) will advantageously make it possible to obtain fluoropolymer films with improved mechanical properties.

[0069] The inorganic filler (I) is usually provided in the mixture in particulate form.

[0070] The inorganic filler (I) particles usually have an average particle size of 0.001 μm to 1000 μm, preferably 0.01 μm to 800 μm, and more preferably 0.03 μm to 500 μm.

[0071] The choice of inorganic filler (I) is not particularly limited; however, it is generally preferred that the inorganic filler has on its surface a group that reacts with compound (M).

[0072] Among the surface reactive groups are hydroxyl groups.

[0073] Without being bound by this theory, the applicant believes that the reaction between at least a portion of the compound (M) and at least a portion of the surface reactive groups of the inorganic filler (I) is mediated by the reaction of at least a portion of the compound (M) with the R XIt is believed that this can be carried out simultaneously with the reaction with at least a portion of the hydroxyl groups of the polymer (A) and the inorganic filler, and that this makes it easier to form a chemical bond between the polymer (A) and the inorganic filler via the inorganic domain derived from the compound (M) in the subsequent hydrolysis and / or polycondensation step.

[0074] Among the inorganic fillers (I) suitable for use in the process of the present invention, mention may be made of inorganic oxides (including mixed oxydes), metal sulfates, metal carbonates, metal sulfides, etc.

[0075] Among the metal oxides, mention may be made of SiO2, TiO2, ZnO, Al2O3.

[0076] Classes of compounds that give particularly good results in the context of this embodiment of the invention are, inter alia, silicates, aluminum silicates and magnesium silicates, all optionally containing an additional metal such as sodium, potassium, iron or lithium.

[0077] These silicates, aluminum silicate and magnesium silicate, are generally known to have a layered structure.

[0078] These silicates, aluminum silicates and magnesium silicates, all of which optionally contain an additional metal such as sodium, potassium, iron or lithium, can be, inter alia, smectic clays, optionally of natural origin, such as montmorillonite, sauconite, vermiculite, hectorite, saponite, nontronite, among others, or can be selected from synthetic clays, such as fluorohectorite, hectorite, laponite, among others, all of which optionally contain an additional metal such as sodium, potassium, iron or lithium.

[0079] The hydrolysis and / or polycondensation of step (iii) of the process of the present invention can be carried out simultaneously with step (ii) of reacting the hydroxyl groups of polymer (A) with the hydrolyzable groups (Y) of compound (M), or can be carried out after said reaction has occurred.

[0080] Typically, particularly for compounds where A is Si, this hydrolysis and / or polycondensation is initiated by the addition of at least one suitable catalyst and / or reactant. Generally, water or a mixture of water and acid can be used to facilitate this reaction.

[0081] The choice of acid is not particularly limited; both organic and inorganic acids can be used, among which formic acid is the preferred acid that can be used in the process of the present invention.

[0082] Generally, the addition of an aqueous medium, preferably containing an acid, will be the preferred method to promote hydrolysis and / or polycondensation.

[0083] The hydrolysis and / or polycondensation can be carried out at room temperature (25°C), but it is generally preferred to carry out the process with heating at a temperature above 50°C.

[0084] The actual temperature will be selected taking into account the boiling point and / or stability of the organic solvent (S), if present. Generally, temperatures between 20°C and 150°C, preferably between 40°C and 120°C, will be preferred.

[0085] In step (iii) of the process of the present invention, the compound (M) and optionally the compound of formula -Y as defined above are m-1 AX 4-m It is understood that the hydrolyzable group Y of the pendant group reacts to obtain a hybrid composite material comprising a polymer domain consisting of a chain of polymer (A) and an inorganic domain consisting of residues derived from compound (M).

[0086] As will be appreciated by those skilled in the art, the hydrolysis and / or polycondensation reactions typically produce low molecular weight by-products, which may be, inter alia, water or alcohols, depending on the nature of the metal compound (M).

[0087] According to a second object of the present invention, there is provided a polymer electrolyte based on the fluoropolymer hybrid organic / inorganic composite material defined above.

[0088] The polymer electrolyte of the present invention comprises an electrolyte solution (ES) entrapped in the sol-gel matrix of a fluoropolymer hybrid organic / inorganic composite. The fluoropolymer hybrid organic / inorganic composite actually has the ability to hold the electrolyte solution, which is entrapped in the sol-gel matrix, providing a free-standing polymer electrolyte.

[0089] The electrolyte solution (ES) comprises at least one metal salt [metal salt (MS)] and a liquid medium [medium (L)].

[0090] The term "metal salt (MS)" is intended to denote a metal salt that contains a conductive ion.

[0091] A variety of metal salts can be used as the metal salt (MS). A metal salt that is stable and soluble in the selected liquid medium (L) is usually used.

[0092] Non-limiting examples of suitable metal salts (MS) include, among others, MeI, Me(PF6), n , Me(BF4) n , Me(CIO4) n , Me(bis(oxalato)borate) n ("Me(BOB) n ”), MeCF3SO3, Me[N(CF3SO2)2] n , Me[N(C2F5SO2)2] n , R F Me[N(CF3SO2)(R F SO2)] n , Me(AsF6)n , Me[C(CF3SO2)3] n , Me2S n (wherein Me is a metal, preferably a transition metal, alkali metal or alkaline earth metal, more preferably Li, Na, K or Cs, and n is the valence of the metal, typically n is 1 or 2).

[0093] Preferred metal salts (MS) are LiI, LiPF, LiBF, LiClO, lithium bis(oxalato)borate ("LiBOB"), LiCF, SO, LiN(CFSO) ("LiTFSI"), LiN(CSO), R F M[N(CF3SO2)(R F SO2)] n , LiAsF6, LiC(CF3SO2)3, Li2S n and combinations thereof.

[0094] The liquid medium may be suitably selected from ionic liquids (ILs), organic carbonates, or mixtures thereof.

[0095] The term "ionic liquid (IL)" is intended herein to refer to compounds formed by the combination of positively charged cations and negatively charged anions that exist in the liquid state at temperatures below 100°C under atmospheric pressure.

[0096] Ionic liquids (ILs) are protic ionic liquids (ILs) p ), aprotic ionic liquids (IL a ), and mixtures thereof.

[0097] "Protic Ionic Liquids (ILs) p )" is used herein to mean that the cation is one or more H + It is intended to refer to ionic liquids that contain hydrogen ions.

[0098] One or more H +Non-limiting examples of cations containing hydrogen ions include imidazolium, pyridinium, pyrrolidinium, or piperidinium rings, among others, where the positively charged nitrogen atom is H + It is bonded to a hydrogen ion.

[0099] Aprotic ionic liquids (ILs) a )" is used herein to mean that the cation is H + It is intended to refer to ionic liquids that do not contain hydrogen ions.

[0100] The ionic liquid (IL) is typically selected from those containing a sulfonium ion as a cation, or an imidazolium ring, a pyridinium ring, a pyrrolidium ring, or a piperidium ring, which may optionally be substituted on the nitrogen atom, in particular by one or more alkyl groups having 1 to 8 carbon atoms, and on the carbon atoms, in particular by one or more alkyl groups having 1 to 30 carbon atoms.

[0101] In the sense of the present invention, the term "alkyl group" denotes a saturated hydrocarbon chain or chains having one or more double bonds and having 1 to 30 carbon atoms, advantageously 1 to 18 carbon atoms, and even more advantageously 1 to 8 carbon atoms. Examples that may be mentioned include methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, pentyl, isopentyl, 2,2-dimethylpropyl, hexyl, 2,3-dimethyl-2-butyl, heptyl, 2,2-dimethyl-3-pentyl, 2-methyl-2-hexyl, octyl, 4-methyl-3-heptyl, nonyl, decyl, undecyl and dodecyl groups.

[0102] In an advantageous embodiment of the invention, the cation of the ionic liquid (IL) is selected from: of the following formula (III): TIFF0007811475000010.tif41161 (wherein R1 and R2 each independently represent an alkyl group having 1 to 8 carbon atoms, and R3, R4, R5, and R6 each independently represent a hydrogen atom or an alkyl group having 1 to 30 carbon atoms, preferably 1 to 18 carbon atoms, and more preferably 1 to 8 carbon atoms), and of formula (IV): A piperidinium ring of the formula TIFF0007811475000011.tif43161 (wherein R1 and R2 each independently represent an alkyl group having 1 to 8 carbon atoms, and R3 to R7 each independently represent a hydrogen atom or an alkyl group having 1 to 30 carbon atoms, preferably 1 to 18 carbon atoms, and more preferably 1 to 8 carbon atoms).

[0103] In a particularly advantageous embodiment of the invention, the cation of the ionic liquid (IL) is selected from: TIFF0007811475000012.tif72161

[0104] The ionic liquid (IL) is advantageously chosen from those which contain as anion those selected from halide anions, perfluoroanions and borates.

[0105] The halide anion is in particular chosen from chloride, bromide, fluoride or iodide anions.

[0106] In a particularly advantageous embodiment of the invention, the anion of the ionic liquid (IL) is selected from: - Formula (SO2CF3)2N - bis(trifluoromethylsulfonyl)imide, - Formula PF6 - hexafluorophosphate, - Formula BF4 - tetrafluoroborate, - Formula: TIFF0007811475000013.tif35161 oxaloborate.

[0107] The amount of one or more ionic liquids (IL) in the liquid medium used in the process of the invention is such that the mixture of step (i) advantageously comprises at least 1% by weight, preferably at least 5% by weight, more preferably at least 10% by weight of ionic liquid (IL), based on the total weight of polymer (A) and ionic liquid (IL) in said mixture.

[0108] The amount of one or more ionic liquids (IL) in the liquid medium used in the process of the invention is such that the mixture of step (i) advantageously comprises at most 95% by weight, preferably at most 85% by weight, more preferably at most 75% by weight, of ionic liquid (IL), based on the total weight of polymer (A) and ionic liquid (IL) in said mixture.

[0109] Suitable organic carbonates are ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, butylene carbonate, vinylene carbonate, fluoroethylene carbonate, fluoropropylene carbonate; and mixtures thereof.

[0110] The medium (L) in the electrolyte solution (ES) may further contain at least one additive [additive (A)].

[0111] When one or more additives (A) are present in a liquid medium, non-limiting examples of suitable additives (A) include, in particular, those that are soluble in the medium (L).

[0112] Additive (A) is preferably selected from the group consisting of organic carbonates such as ethylene carbonate, propylene carbonate, mixtures of ethylene carbonate and propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl-methyl carbonate, butylene carbonate, vinylene carbonate, fluoroethylene carbonate, fluoropropylene carbonate, and mixtures thereof.

[0113] The amount of one or more additives (A) in the liquid medium, if present, is typically comprised between 0.1% and 95% by weight, preferably between 1.0% and 70% by weight, and more preferably between 5.0% and 50% by weight, based on the total weight of the liquid medium.

[0114] The polymer electrolyte of the present invention can be processed into a film to provide a polymer electrolyte membrane for use as a separator in an electrochemical device, particularly a metal ion secondary battery.

[0115] A further object of the present invention relates to a method for producing a membrane comprising processing the polymer electrolyte of the present invention by compression molding or extrusion techniques.

[0116] A further object of the present invention is therefore a polymer electrolyte membrane obtainable by the method defined above.

[0117] The membrane thus obtained typically has a thickness of 5 μm to 100 μm, preferably 10 μm to 30 μm.

[0118] The polymer electrolyte membranes of the present invention can be advantageously used as polymer electrolyte separators in electrochemical and photoelectrochemical devices.

[0119] Non-limiting examples of suitable electrochemical devices include, inter alia, secondary batteries, especially lithium-ion batteries and lithium-sulfur batteries, and capacitors, especially lithium-ion capacitors.

[0120] The present invention further relates to a metal-ion secondary battery comprising, as a polymer electrolyte separator, the polymer electrolyte membrane of the present invention as defined above.

[0121] Metal-ion secondary batteries are typically formed by assembling a negative electrode (anode), the polymer electrolyte membrane of the present invention as defined above, and a positive electrode (cathode).

[0122] The metal ion secondary battery is preferably an alkaline or alkaline earth secondary battery, more preferably a lithium ion secondary battery.

[0123] To the extent that the disclosure of any patents, patent applications, and publications incorporated herein by reference contradicts the statements of this application to the extent that the term may be unclear, the statements of this application shall control.

[0124] The present invention will now be described in more detail with reference to the following examples, the purpose of which is illustrative only and not intended to limit the scope of the invention.

[0125] Experimental section raw materials Tetraethyl orthosilicate (TEOS), >99% purity, commercially available as a liquid from Aldrich Chemistry. Lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). Ionic liquid (IL): N-propyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (Pyr13TFSI) of the following formula: TIFF0007811475000014.tif35161ES: 0.5M LiTFSI in Pyr13TFSI.

[0126] flexibility The flexibility of the films was evaluated according to ASTM D 790-10 Standard Test Method for Flexural Properties of Unreinforced and Reinforced Plastics and Electrical Insulating Materials under the following operating conditions: Temperature: 24.2℃; Humidity: 32.5%; Speed: 1.5mm / min.

[0127] The results are presented in terms of elastic modulus (MPa): the lower the value, the more flexible the polymer electrolyte.

[0128] Measurement of ionic conductivity (σ) The polymer electrolyte membrane is placed in an 18 mm stainless steel EL-CELL prototype. The resistance of the polymer electrolyte membrane is measured at 25° C. and the ionic conductivity (σ) is calculated using the following equation: TIFF0007811475000015.tif15161 (where d is the film thickness and R b is the bulk resistance and S is the area of ​​the stainless steel electrode).

[0129] Measurement of intrinsic viscosity of polymer (A) The intrinsic viscosity (η) [dl / g] was calculated using an Ubbelhode viscometer based on the fall time at 25°C of a solution obtained by dissolving the polymer (A) in N,N-dimethylformamide at a concentration of about 0.2 g / dl, according to the following formula: TIFF0007811475000016.tif15161 (where c is the polymer concentration [g / dl] and η r is the relative viscosity, i.e., the ratio between the dropping time of the sample solution and the dropping time of the solvent, and η sp is the specific viscosity, i.e., η r -1 and Γ is an experimental factor corresponding to 3 for polymer (A).

[0130] Example 1: Preparation of VDF copolymers (Polymers A1, A2, and Comparative Polymers 1, 2, 3, and 4) A 4-liter reactor equipped with an impeller operating at 650 rpm was charged successively with 2850 g of demineralized water and 0.6 g of Alkox® E-45 as a suspending agent and 0.2 g of Methocell® K100 / kg Mni (initial amounts of monomers fed to the reactor before reaction). The reactor was purged with continuous vacuum (30 mmHg) and nitrogen purge at 20°C. A 75 wt% solution of t-amyl perpivalate in isododecane (TAPPI) was then added. Diethyl carbonate (DEC), an initial amount of HEA, HFP, and CTFE, followed by approximately 1200 g of VDF, were charged to the reactor. The amounts of monomers and temperature conditions are shown in Table 1.

[0131] The reactor was gradually heated to a set-point temperature of 57°C, and the pressure was fixed at 120 bar. The pressure was constantly kept equal to 120 bar by feeding an aqueous hydroxyethyl acrylate solution during the polymerization as shown in Table 1. After this feeding, no further aqueous solution was introduced, and the pressure began to drop. The polymerization was stopped by venting the reactor until atmospheric pressure was reached. A VDF conversion of approximately 80% was reached. The CTFE and HEA were practically all consumed, with approximately half of the HFP remaining unreacted. The polymer thus obtained was then recovered, washed with demineralized water, and dried overnight at 65°C.

[0132] TIFF0007811475000017.tif103170

[0133] MnT is the total amount of monomers fed to the reactor.

[0134] Example 2: Solubility test 8% by weight compositions of each of Comparative Polymers 1 to 4, Polymer A1, and Polymer A2 in acetone were prepared. A clear, non-cloudy solution at room temperature indicates the solubility of the polymer in acetone at 25°C. The compositions were also tested at 50°C to assess solubility. The results are summarized in Table 2.

[0135] TIFF0007811475000018.tif89170

[0136] The results show that the polymers according to the invention are soluble in acetone at room temperature due to the simultaneous presence of a certain amount of repeat units derived from CTFE, MA, and HFP. The same is not true for polymers containing only repeat units derived from CTFE and one of the monomers MA or HFP, or for polymers containing different amounts of CTFE monomer.

[0137] Example 3: Preparation of polymer 5: VDF / HEA (0.8 wt%) / HFP (5 wt%) copolymer with an intrinsic viscosity of 0.11 l / g in DMF at 25°C. An 80-liter reactor equipped with an impeller operating at 250 rpm was successively charged with 50.2 kg of demineralized water, 3.80 g of METHOCEL® K100 GR as a suspending agent, and 15.21 g of Alkox® E45. The reactor was purged with multiple sequences of vacuum (30 mmHg) and nitrogen purge at 20°C. Next, 187.3 g of a 75 wt. % solution of t-amyl perpivalate initiator in isododecane was introduced. The stirring speed was increased to 300 rpm. Finally, 16.3 g of hydroxyethyl acrylate (HEA) and 2555 g of hexafluoropropylene (HFP) monomer were introduced into the reactor, followed by 22.8 kg of vinylidene fluoride (VDF). The reactor was gradually heated to a set-point temperature of 55°C, and the pressure was fixed at 120 bar. During the polymerization, the pressure was kept constant at 120 bar by feeding 16.96 kg of an aqueous solution containing 188 g of HEA. After this feeding, no further aqueous solution was introduced and the pressure began to drop. The polymerization was then stopped by venting the reactor until atmospheric pressure was reached. Approximately 81% conversion of the comonomer was obtained. The polymer thus obtained was then recovered, washed with demineralized water and oven-dried at 65°C.

[0138] Example 4: Preparation of polymer electrolyte using polymer A1 In a flask equipped with a condenser, polymer A1 (4.14 g) was dissolved in acetone (23.46 g) (15 wt %) and heated at 60° C. for 30 min. ES (5 g) and TEOS (0.35 g) were added to the solution, which was then stirred at 40° C. for 10 min. A mixture containing 39 vol % (45 wt %) of polymer A1, 60 vol % (54 wt %) of the electrolyte solution, and 1.2 vol % (1.09 wt %) of SiO (the fully condensed equivalent of TEOS) was obtained. Then, 0.154 g of formic acid was added to the mixture, and the mixture was stirred at 35° C. for 2 minutes. The mixture was cast onto a Halar® membrane support using a doctor blade. The blade opening was set to 650 μm. A film of the solution approximately 650 μm thick was obtained. The film was dried at room temperature for 15 minutes and then at 50°C for 40 minutes in a ventilated oven. A thermal post-treatment was then performed, involving a temperature increase to 150°C lasting 25 minutes, after which the film was peeled off from the support. Polymer electrolyte films with thicknesses of 74-78 μm were obtained. The films possessed ionic conductivity and flexibility, as shown in Table 3.

[0139] Example 5: Preparation of polymer electrolyte using polymer A2 In a flask equipped with a condenser, polymer A2 (4.97 g) was dissolved in acetone (19.87 g) (20 wt %) and heated at 60° C. for 30 minutes. ES (6 g) and TEOS (0.419 g) were added to the solution, which was then stirred at 40° C. for 10 minutes. A mixture containing 39 vol % (45 wt %) of polymer A2, 60 vol % (54 wt %) of the electrolyte solution, and 1.2 vol % (1.09 wt %) of SiO (the fully condensed equivalent of TEOS) was obtained. Then, 0.185 g of formic acid was added to the mixture, and the mixture was stirred at 35° C. for 2 minutes. The mixture was cast onto a Halar® membrane support using a doctor blade. The blade opening was set to 650 μm. A solution membrane approximately 650 μm thick was obtained. The membrane was dried at room temperature for 15 minutes and then at 50°C for 40 minutes in a ventilated oven. A thermal post-treatment was then performed, involving a temperature increase to 150°C lasting 25 minutes, after which the membrane was peeled off from the support. A polymer electrolyte membrane with a thickness of 74 μm was obtained. The membrane had ionic conductivity and flexibility, as shown in Table 3.

[0140] Comparative Example 6: Preparation of polymer electrolyte using polymer 5 In a flask equipped with a condenser, polymer 5 (8 g) was dissolved in DMF (32 g) (20 wt %) and heated at 60° C. for 30 min. ES (8 g) and TEOS (0.56 g) were added to the solution, which was then stirred at 40° C. for 10 min. A mixture containing 39 vol % (45 wt %) of polymer 5, 60 vol % (54 wt %) of the electrolyte solution, and 1.2 vol % (1.09 wt %) of SiO (the fully condensed equivalent of TEOS) was obtained. Then, 0.247 g of formic acid was added to the mixture, and the mixture was stirred at 35° C. for 2 minutes. The mixture was cast onto a Halar® membrane support using a doctor blade. The blade opening was set to 650 μm. A solution membrane approximately 650 μm thick was obtained. The membrane was dried at room temperature for 15 minutes and then at 50°C for 40 minutes in a ventilated oven. A thermal post-treatment was then performed, involving a temperature increase to 150°C lasting 25 minutes, and the membrane was peeled off from the support. A polymer electrolyte membrane with a thickness of 77 μm was obtained. The membrane had ionic conductivity and flexibility, as shown in Table 3.

[0141] TIFF0007811475000019.tif37170

[0142] The data in Table 3 show that the polymer electrolyte films of the present invention are more flexible than standard polymer electrolytes of the prior art.

Claims

1. -(a) repeating units derived from vinylidene fluoride (VDF); (b) a repeating unit derived from chlorotrifluoroethylene (CTFE); (c) Formula (I): wherein each of R1, R2, and R3, which may be equal to or different from one another, is independently a hydrogen atom or a C 1 -C 3 hydrocarbon group, and R x is a C 1 -C 5 hydrocarbon moiety containing at least one hydroxyl group. a repeating unit derived from at least one hydrophilic (meth)acrylic monomer [monomer (MA)] of the formula: (d) repeat units derived from one or more fluorinated comonomers (F) different from VDF and CTFE; at least one semi-crystalline vinylidene fluoride (VDF) copolymer [polymer (A)] comprising The total amount of repeating units b) is comprised between 6% and 25% by weight, based on the total weight of repeating units of polymer (A), and the total amount of repeating units d) is comprised between 0.5% and 4% by weight, based on the total weight of repeating units of polymer (A); and having a heat of fusion of at least 0.4 J / g as measured in accordance with ASTM D3418; at least one semi-crystalline vinylidene fluoride (VDF) copolymer [polymer (A)]; - Formula (II): X ４－ｍ AY ｍ (II) (wherein m is an integer from 1 to 4, A is a metal selected from the group consisting of Si, Ti and Zr, Y is a hydrolyzable group, and X is a hydrocarbon group optionally containing one or more functional groups). and at least one compound (M) of the formula: providing a mixture of: (ii) Pendant-Y ｍ－１ AX ４－ｍ R of the monomer (MA) of the polymer (A) to obtain a graft polymer containing the group (wherein m, Y, A, and X have the same meanings as detailed above). Ｘ reacting at least a portion of the hydroxyl groups of with at least a portion of the compound (M); (iii) the compound (M) detailed above and / or pendant-Y ｍ－１ AX ４－ｍ hydrolyzing and / or polycondensing the groups to obtain a fluoropolymer hybrid organic / inorganic composite containing inorganic domains; 1. A method for producing a fluoropolymer hybrid organic / inorganic composite material containing inorganic domains, comprising: The method wherein the mixture of step (i) comprises acetone.

2. 1. A method for producing a polymer electrolyte based on a fluoropolymer hybrid organic / inorganic composite material containing an inorganic domain, said hybrid comprising: (I) － (a) repeating units derived from vinylidene fluoride (VDF); (b) a repeating unit derived from chlorotrifluoroethylene (CTFE); (c) Formula (I): (wherein R1, R2, and R3, which are equal to or different from each other, are independently a hydrogen atom or C １ ~C ３ is a hydrocarbon group, R Ｘ optionally containing at least one hydroxyl group; １ ~C ５ hydrocarbon moiety) A repeating unit derived from at least one hydrophilic (meth)acrylic monomer [monomer (MA)] of the formula (I), and (d) repeat units derived from one or more fluorinated comonomers (F) different from VDF and CTFE; at least one semi-crystalline vinylidene fluoride (VDF) copolymer [polymer (A)] comprising a semi-crystalline vinylidene fluoride (VDF) copolymer [polymer (A)], in which the total amount of repeating units b) is comprised between 6% and 25% by weight, based on the total weight of repeating units of polymer (A), and the total amount of repeating units d) is comprised between 0.5% and 4% by weight, based on the total weight of repeating units of polymer (A), and which has a heat of fusion of at least 0.4 J / g as measured in accordance with ASTM D3418; - Formula (II): X ４－ｍ AY ｍ (II) (wherein m is an integer from 1 to 4, A is a metal selected from the group consisting of Si, Ti and Zr, Y is a hydrolyzable group, and X is a hydrocarbon group optionally containing one or more functional groups). and at least one compound (M) of the formula: an electrolyte solution (ES) comprising at least one metal salt [metal salt (MS)] and a liquid medium [medium (L)], providing a mixture of: (II) Pendant-Y ｍ－１ AX ４－ｍ R of the monomer (MA) of the polymer (A) to obtain a graft polymer containing the group (wherein m, Y, A, and X have the same meanings as detailed above). Ｘ reacting at least a portion of the hydroxyl groups of the group with at least a portion of said compound (M); (III) Compound (M) and / or pendant-Y ｍ－１ AX ４－ｍ hydrolyzing and / or polycondensing the groups to obtain a polymer electrolyte based on a fluoropolymer hybrid organic / inorganic composite containing inorganic domains entrapped in the electrolyte solution (ES); obtained by a process comprising: The method wherein the mixture of step (i) comprises acetone.

3. The at least one metal salt (MS) is selected from the group consisting of MeI, Me(PF ６ ) ｎ , Me(BF ４ ) ｎ , Me(ClO ４ ) ｎ , Me(bis(oxalato)borate) ｎ ("Me (BOB) ｎ "), MeCF ３ SO ３ , Me[N(CF ３ SO ２ ) ２ ] ｎ , Me[N(C ２ F ５ SO ２ ) ２ ] ｎ , Me[N(CF ３ SO ２ ) (R Ｆ SO ２ )] ｎ (In the formula, R Ｆ is C ２ F ５ , C ４ F ９ or CF ３ OCF ２ CF ２ ), Me(AsF ６ ) ｎ , Me[C(CF ３ SO ２ ) ３ ] ｎ , Me ２ S ｎ wherein Me is a metal and n is the valence of the metal, typically n is 1 or 2.

3. The method of claim 2, wherein the compound is selected from the group consisting of:

4. 4. The method according to claim 2 or 3, wherein the liquid medium (L) is selected from an ionic liquid (IL), an organic carbonate, or a mixture thereof.

5. A method for producing a polymer electrolyte membrane, comprising processing the polymer electrolyte obtained by the method according to any one of claims 2 to 4 by compression molding or extrusion techniques.

6. A method for producing an electrochemical device comprising a polymer electrolyte obtained by the method of claim 5.

7. The method of claim 6, wherein the electrochemical device is a metal-ion secondary battery.

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