Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
  • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
  • H01M10/0565—Polymeric materials, e.g. gel-type or solid-type
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/052—Li-accumulators
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/052—Li-accumulators
  • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
  • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
  • H01M50/403—Manufacturing processes of separators, membranes or diaphragms
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
  • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
  • H01M50/409—Separators, membranes or diaphragms characterised by the material
  • H01M50/411—Organic material
  • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
  • H01M50/426—Fluorocarbon polymers
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
  • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
  • H01M50/409—Separators, membranes or diaphragms characterised by the material
  • H01M50/446—Composite material consisting of a mixture of organic and inorganic materials
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M2300/00—Electrolytes
  • H01M2300/0017—Non-aqueous electrolytes
  • H01M2300/0065—Solid electrolytes
  • H01M2300/0082—Organic polymers
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/10—Energy storage using batteries

Definitions

• the present invention relates generally to the field of electrical energy storage in all-solid-state batteries, in particular in secondary batteries of the Li-ion type. More specifically, the invention relates to a solid electrolyte and a method of manufacturing a film therefrom. This film is intended for an all-solid battery separator or electrolyte application, particularly for Li-ion batteries. The invention also relates to an all-solid battery comprising such a separator and/or such a non-porous film.
• a secondary battery such as Li-ion comprises at least one negative electrode or anode coupled to a copper current collector, a positive electrode or cathode coupled with an aluminum current collector, a separator and an electrolyte.
• the electrolyte consists of an alkali metal salt, generally a lithium salt, mixed with a solvent which is a mixture of organic carbonates, chosen to optimize the transport and dissociation of ions.
• a high dielectric constant favors the dissociation of ions, and therefore, the number of ions available in a given volume, while a low viscosity is favorable to ionic diffusion which plays an essential role, among other parameters, in the speeds of charging and discharging of the electrochemical system.
• Li-ion batteries conventionally use liquid electrolytes composed of solvent(s), alkali metal salt(s) such as lithium salts and additive(s). These electrolytes have good ionic conductivity but are likely to leak or ignite if the battery is damaged.
• solid electrolytes helps overcome these difficulties.
• solid electrolytes are generally less conductive than liquid electrolytes.
• the difficulty with solid electrolytes is to combine high ionic conductivity, good electrochemical stability as well as sufficient temperature resistance. Ionic conductivity should be equivalent to that of liquid electrolytes.
• Electrochemical stability should allow the use of the electrolyte with cathode materials capable of operating at high voltage (>4.5 V). Likewise, the solid electrolyte must operate at least up to 80°C.
• the separator must, in particular, prevent the formation of dendrites during charge/discharge cycles.
• the solid electrolyte must demonstrate better safety, but this does not can be to the detriment of other performances.
• the solid electrolyte must be able to be handled (stretched) and rolled.
• PVDF Poly(vinylidene fluoride)
• P(VDF-HFP) copolymer copolymer of vinylidene fluoride (VDF) and hexafluoropropylene (HFP)
• VDF vinylidene fluoride
• HFP hexafluoropropylene
• solid or quasi-solid electrolytes having a polymeric matrix are generally complex to manufacture and require going through several stages: dissolution, addition of co-components, homogenization, deposition and drying. For each of these steps, controlling the dry extract as well as the homogeneity of the “slurry” is essential to achieve the best possible performance and ensure that they are homogeneous across the entire manufactured object.
• Document WO 2020126750 describes solid electrolyte compositions comprising a mixture of fluoropolymer and an isocyanate compound to form a cross-linked network.
• the film is prepared in the presence of acetone.
• the implementation of a film in the presence of acetone does not make it possible to obtain a homogeneous film because of the low vapor pressure of acetone, which impacts the ionic conductivity of the film and the final performance of the film. battery. Additionally, low vapor pressure causes process safety issues.
• the invention therefore aims to remedy at least one of the drawbacks of the prior art, namely to prepare a film of homogeneous solid electrolytes having good performance.
• the present invention relates to a process for preparing a solid electrolyte in the form of a film comprising the steps of:
• said at least one organic solvent A2 has a donor number greater than 4 kcal/mol and a saturated vapor pressure less than 24 kPa at 20°C; and in that said at least plasticizer B2 comprises at least one ionic liquid.
• solution C is obtained according to the following steps:
• said at least one organic solvent A2 has a flash point greater than -15°C.
• said at least one organic solvent A2 has a saturated vapor pressure greater than 7 Pa at 20°C. This makes it possible to evaporate the solvent more easily and thus avoid too high a solvent content in the film obtained by the process of the invention.
• said at least one organic solvent A2 has a mass water content of less than 5000 ppm. Limiting the water content makes it possible to avoid the degradation of certain components used in the process.
• said at least one fluoropolymer Al is a homopolymer of vinylidene fluoride or a copolymer comprising monomeric units derived from vinylidene fluoride and monomeric units derived from a monomer selected from the group consisting of trifluoroethylene, chlorotrifluoroethylene, 1,2-difluoroethylene, tetrafluoroethylene, hexafluoropropylene or a mixture thereof.
• said at least one alkali metal salt B1 is selected from the group consisting of LiCF 3 SO 3 , LiPF 6 , LiCIO 4 , LiBF 4 , LiB(C 2 O 4 ) 2 , LiN(SO 2 F) 2 , LiN( SO 2 CF 3 ) 2 , LiN(SO 2 C 2 F 3 ) 2 , LiN( SO 2 C 2 F 5 ) 2 , LiN(SO 2 F)(SO 2 CF 3 ), LiN( SO 2 F)(SO 2 C 2 F 5 ), LiN(SO 2 CF 3 )(SO 2 C 2 F 5 ),LiAsF 6 , LiBF 2 C 2 O 4 , UNO 3 , LiPF3(CF 2 CF 3 ) 3 , LiBETI, LiTDI, NaTDI, KTDI, NaCIO 4 , KCIO 4 , NaPF 6 , KPF 6 , NaBF 4 , KBF 4 , NaAsF 6 , KA
• said at least one plasticizer B2 is an ionic liquid which comprises an anion selected from the group consisting of tetrafluoroborate (BF4-), bis(oxalato)borate BOB-, hexafluorophosphate (PF6-), hexafluoroarsenate (AsF6-), triflate or trifluoromethylsulfonate (CF3SO3-), bis(fluorosulfonyl)imide (FSI-), bis-(trifluoromethanesulfonyl)imide (TFSI-), nitrate (NO3-), 4, 5-dicyano-2-(trifluoromethyl)imidazole (TDI-), an acrylate or a methacrylate; and a cation selected from the group consisting of ammonium, sulfonium, pyridinium, pyrrolidinium, imidazolium, imidazolinium, phosphonium, gua cation selected from
• said film has a porosity of less than 10%.
• said film has a thickness varying by less than 20% over its entire length.
• the present invention provides a composition for the preparation of a solid electrolyte comprising at least one fluoropolymer Al, at least one organic solvent A2, at least one alkali metal salt B1 and at least one plasticizer B2 comprising at least one least one ionic liquid characterized in that said at least one organic solvent A2 has a donor number greater than 4 kcal/mol, a saturated vapor pressure of 7 Pa to 24 kPa at 20°C, a flash point greater than -15° C and a mass water content less than 5000 ppm.
• said at least one fluoropolymer Al is as defined in the present application
• said at least one alkali metal salt B1 is as defined in the present application
• said at least one plasticizer B2 is such as defined in this application.
• the present invention provides a film comprising from 15 to 70% by weight of at least fluoropolymer Al, from 10 to 80% by weight of plasticizer(s) B2 comprising at least one ionic liquid, from 2 to 30% by weight of alkali metal salt(s) Bl, and 1 ppb at 5000 ppm of water.
• said film also comprises from 1 ppb to 15% of said at least one organic solvent A2 as defined in the present application.
• said film consists of 15 to 70% by weight of at least fluoropolymer Al, from 10 to 80% by weight of plasticizer(s) B2 comprising at least one ionic liquid, from 2 to 30 % by weight of alkali metal salt(s) Bl, from 1 ppb to 15% of said at least one organic solvent A2 and from 1 ppb to 5000 ppm of water; the sum of the constituents being equal to 100.
• said film has an ionic conductivity of 0.01 to 5 mS/cm, preferably 0.05 to 5 mS/cm, advantageously 0.5 to 5 mS/cm at 25°C, measured by electrochemical impedance spectroscopy.
• said film is obtained by the process according to the present invention.
• said film has a thickness varying by less than 20% over its entire length.
• said film has a porosity of less than 10%.
• the present invention provides a separator for a rechargeable Li-ion battery, comprising the film according to the present invention.
• the present invention provides an electrochemical device selected from the group consisting of batteries, capacitor, electric double-layer electrochemical capacitor, and membrane-electrode assembly (MEA) for a fuel cell or an electrochromic device, said device comprising a film according to the present invention.
• an electrochemical device selected from the group consisting of batteries, capacitor, electric double-layer electrochemical capacitor, and membrane-electrode assembly (MEA) for a fuel cell or an electrochromic device, said device comprising a film according to the present invention.
• the present invention provides an all-solid-state battery comprising an anode, a cathode and a separator, in which said separator comprises the film according to the present invention.
• the present invention provides an all-solid-state battery comprising an anode, a cathode and a separator, in which the anode and/or the cathode comprises a film according to the present invention.
• Fig. 1 represents the evolution of the mass of a film as a function of the coating length.
• Fig. 2 represents the evolution of the thickness of a film as a function of the coating length.
• a process for preparing a solid electrolyte in the form of a film comprises a step of providing a solution C comprising at least one fluoropolymer Al, at least one organic solvent A2, at least one alkali metal salt B1 and at least one plasticizer B2.
• said at least one plasticizer B2 comprises at least one ionic liquid.
• This solution C is deposited on a support D to form a film.
• said method also comprises a step of drying said film to eliminate said at least one organic solvent A2 used during the preparation.
• the method according to the present invention comprises the steps of:
• solution C is obtained by mixing two distinct solutions A and B.
• Solution A comprises said at least one fluoropolymer Al and said at least one organic solvent A2.
• Solution B comprises said at least one alkali metal salt B1 and said at least one plasticizer B2.
• Solution B may also include an organic solvent. The latter may be said organic solvent A2 or any other organic solvent capable of solubilizing said alkali metal salt B1 and/or said plasticizer B2. Solutions A and B are then mixed to obtain solution C.
• the step of preparing said solution A is carried out at a temperature between 15°C and 90°C, preferably between 15°C and 60°C.
• the step of preparing said solution B is carried out at a temperature between 15°C and 90°C, preferably between 15°C and 60°C.
• the step of depositing said solution C on the support D is carried out at a temperature between 15°C and 100°C, preferably between 15°C and 90°C.
• the film drying step can be carried out at a temperature of 20°C to 120°C, preferably 20°C to 90°C, in particular 40°C to 80°C. This step is generally implemented under extraction.
• Said fluoropolymer Al comprising monomeric units containing at least one fluorine atom.
• said fluoropolymer Al contains in its chain at least one monomer chosen from compounds containing a vinyl group capable of opening to polymerize and which contains, directly attached to this vinyl group, at least one atom fluorine, a fluoroalkyl group or a fluoroalkoxy group.
• said fluoropolymer Al comprises at least monomeric units derived from vinylidene fluoride.
• the fluoropolymer Al can be a homopolymer or a copolymer.
• the copolymer may also comprise non-fluorinated monomers.
• the fluoropolymer Al is a homopolymer of vinylidene fluoride.
• the fluoropolymer Al is a copolymer comprising monomeric units derived from vinylidene fluoride and monomeric units derived from at least one other comonomer copolymerizable with vinylidene fluoride.
• Comonomers compatible with vinylidene fluoride can be halogenated (fluorinated, chlorinated or brominated) or non-halogenated.
• Chlorofluoroethylene can refer to either 1-chloro-l-fluoroethylene or l-chloro-2-fluoroethylene.
• the 1-chloro-1-fluoroethylene isomer is preferred.
• the chlorotrifluoropropene is preferably 1-chloro-3,3,3-trifluoropropene or 2-chloro-3,3,3-trifluoropropene.
• the fluoropolymer Al is a copolymer comprising monomeric units derived from vinylidene fluoride and monomeric units derived from a monomer selected from the group consisting of trifluoroethylene, chlorotrifluoroethylene, 1,2-difluoroethylene, tetrafluoroethylene and hexafluoropropylene or a mixture of these.
• the mass content of the vinylidene fluoride units is at least 50%, preferably at least 60%, more preferably greater than 70% and advantageously greater than 80%.
• the fluoropolymer Al is a copolymer comprising monomeric units derived from vinylidene fluoride and monomeric units derived from hexafluoropropylene; preferably the mass content of the monomeric units derived from vinylidene fluoride is at least 50%, preferably at least 60%, more preferably greater than 70% and advantageously greater than 80%.
• the fluoropolymer Al is a copolymer comprising monomeric units derived from vinylidene fluoride and monomeric units derived from hexafluoropropylene; the mass content of the vinylidene fluoride units is greater than 65% and the mass content of the hexafluoropropylene units is less than 35%.
• the fluoropolymer Al consists of a mixture of a homopolymer of vinylidene fluoride (PVDF) and at least one copolymer of VDF, with a mass content of PVDF homopolymer ranging from 0.1 to 20% based on the weight of said mixture.
• PVDF vinylidene fluoride
• said fluoropolymer Al consists of a mixture of a PVDF homopolymer and a P(VDF-HFP) copolymer.
• said fluoropolymer Al consists of a mixture of two VDF copolymers of different structures.
• the fluoropolymer Al is functionalized in whole or in part, which allows it to improve adhesion to metal.
• said fluoropolymer Al may comprise monomer units carrying at least one of the functions selected from the group consisting of carboxylic acid, carboxylic acid anhydride, carboxylic acid esters, epoxy groups such as glycidyl, amide, hydroxyl , carbonyl, mercapto, sulfide, oxazoline, phenolics, ester, ether, siloxane, sulfonic, sulfuric, phosphoric, phosphonic; preferably at least one carboxylic acid or hydroxyl function.
• the function is introduced by a chemical reaction which can be grafting, or a copolymerization of the monomeric units carrying a fluorine atom with a monomer carrying at least one of said functional groups and a vinyl function capable of copolymerizing with the fluorinated monomer, according to techniques well known to those skilled in the art.
• the functional group carries a carboxylic acid function which is a (meth)acrylic acid type group chosen from acrylic acid, methacrylic acid, hydroxyethyl(meth)acrylate, hydroxypropyl(meth) acrylate, hydroxyethylhexyl(meth)acrylate and acryloyloxy propyl succinate.
• a (meth)acrylic acid type group chosen from acrylic acid, methacrylic acid, hydroxyethyl(meth)acrylate, hydroxypropyl(meth) acrylate, hydroxyethylhexyl(meth)acrylate and acryloyloxy propyl succinate.
• the units carrying the carboxylic acid function further comprise a heteroatom chosen from oxygen, sulfur, nitrogen and phosphorus.
• the functionality is introduced via the transfer agent used during the synthesis process.
• the transfer agent is a polymer with a molar mass less than or equal to 20,000 g/mol and carrying functional groups chosen from the groups: carboxylic acid, carboxylic acid anhydride, carboxylic acid esters, epoxy groups (such as glycidyl), amide, hydroxyl, carbonyl, mercapto, sulfide, oxazoline, phenolics, ester, ether, siloxane, sulfonic, sulfuric, phosphoric, phosphonic.
• An example of such a transfer agent are acrylic acid oligomers.
• the transfer agent is an oligomer of acrylic acid with a molar mass less than or equal to 20,000 g/mol.
• the functional group content of the PVDF is at least 0.01 mol%, preferably at least 0.1 mol%, and at most 15 mol%, preferably at most 10 mol%.
• PVDF preferably has a high molecular weight.
• high molecular weight as used here, is meant a PVDF having a melt viscosity greater than 100 Pa.s, preferably greater than 500 Pa.s, more preferably greater than 1000 Pa.s, according to the ASTM D-3835 method measured at 232°C and 100 sec-1.
• PVDF homopolymers and the VDF copolymers used in the invention can be obtained by known polymerization methods such as emulsion or suspension polymerization.
• they are prepared by an emulsion polymerization process in the absence of fluorinated surfactant.
• Polymerization of PVDF results in a latex generally having a solids content of 10 to 60% by weight, preferably 10 to 50%, and having a weight average particle size of less than 1 micrometer, preferably less than 1000 nm , preferably less than 800 nm, and more preferably less than 600 nm.
• the weight average size of the particles is generally at least 20 nm, preferably at least 50 nm, and advantageously the average size is in the range of 100 to 400 nm.
• the polymer particles can form agglomerates whose weight average size is 1 to 30 micrometers, and preferably 2 to 10 micrometers. Agglomerates may break into discrete particles during formulation and application to a substrate.
• the homopolymer PVDF and VDF copolymers are composed of bio-based VDF.
• biosourced means “from biomass”. This makes it possible to improve the ecological footprint of the polymer.
• the biosourced VDF can be characterized by a renewable carbon content, that is to say carbon of natural origin and coming from a biomaterial or biomass, of at least 1 atomic % as determined by the carbon content. 14C according to standard NF EN 16640.
• renewable carbon indicates that the carbon is of natural origin and comes from a biomaterial (or biomass), as indicated below.
• the bio-carbon content of the VDF can be greater than 5%, preferably greater than 10%, preferably greater than 25%, preferably greater than or equal to 33%, preferably greater than 50% , preferably greater than or equal to 66%, preferably greater than 75%, preferably greater than 90%, preferably greater than 95%, preferably greater than 98%, preferably greater than 99%, advantageously equal to 100% .
• Organic solvent A2 preferably greater than 10%, preferably greater than 25%, preferably greater than or equal to 33%, preferably greater than 50% , preferably greater than or equal to 66%, preferably greater than 75%, preferably greater than 90%, preferably greater than 95%, preferably greater than 98%, preferably greater than 99%, advantageously equal to 100% .
• Said organic solvent A2 makes it possible to solubilize said fluoropolymer Al.
• said organic solvent A2 has a donor number greater than 4 kcal/mol.
• said organic solvent has a donor number greater than 5 kcal/mol.
• the donor index, or donor number, of a solvent represents the -AH value, AH being the enthalpy of the interaction between the solvent and antimony pentachloride (according to the method described in Journal of Solution Chemistry, vol. 13, no. 9, 1984).
• said organic solvent A2 has a donor number greater than 6 kcal/mol, advantageously greater than 7 kcal/mol, preferably greater than 8 kcal/mol, more preferably greater than 9 kcal/mol, in particular greater than 10 kcal/mol.
• said organic solvent A2 has a donor number less than 30 kcal/mol, advantageously less than 29 kcal/mol, preferably less than 28 kcal/mol, more preferably less than 27 kcal/mol, in particular less than 26 kcal/mol, more particularly less than 25 kcal/mol, preferably less than 24 kcal/mol, advantageously preferred less than 23 kcal/mol, preferably less than 22 kcal/mol, so more preferably less than 21 kcal/mol, more preferably less than 20 kcal/mol.
• said organic solvent A2 has a donor number greater than 6 kcal/mol, advantageously greater than 7 kcal/mol, preferably greater than 8 kcal/mol, more preferably greater than 9 kcal/mol, in particular greater than 10 kcal/mol; and less than 30 kcal/mol, advantageously less than 29 kcal/mol, preferably less than 28 kcal/mol, more preferably less than Tl kcal/mol, in particular less than 26 kcal/mol, more particularly less than 25 kcal/mol mol, preferably less than 24 kcal/mol, advantageously preferred less than 23 kcal/mol, preferably less than 22 kcal/mol, more preferably less than 21 kcal/mol, particularly preferred less than 20 kcal/mol.
• said organic solvent A2 has a donor number of between 5 and 30 kcal/mol, advantageously between 5 and 25 kcal/mol, preferably between 10 and 20 kcal/mol.
• an organic solvent A2 or a mixture of specific organic solvent A2 is preferred.
• the use of an organic solvent having a saturated vapor pressure as explained in the different embodiments below makes it possible to improve the quality of the film produced.
• Said organic solvent A2 has a saturated vapor pressure of less than 24 kPa at 20°C.
• said organic solvent A2 has a saturated vapor pressure of less than 23 kPa, advantageously less than 22 kPa, preferably less than 21 kPa, more preferably less than 20 kPa at 20°C, in particular less than 18 kPa at 20°C, more particularly less than 16 kPa at 20°C, preferably less than 14 kPa at 20°C, advantageously less than 12 kPa at 20°C.
• said organic solvent A2 has a saturated vapor pressure greater than 7 Pa, advantageously greater than 8 Pa, preferably greater than 9 Pa, more preferably greater than 10 Pa at 20°C, in particular greater than 25 Pa, more particularly greater than 50 Pa, preferably greater than 100 Pa, advantageously preferably greater than 500 Pa at 20°C. This makes it possible to avoid too high a residual solvent content in the film produced.
• said organic solvent A2 has a saturated vapor pressure of less than 24 kPa at 20°C.
• said organic solvent A2 has a saturated vapor pressure of less than 23 kPa, advantageously less than 22 kPa, preferably less than 21 kPa, more preferably less than 20 kPa at 20°C, in particular less than 18 kPa at 20°C, more particularly less than 16 kPa at 20°C, preferably less than 14 kPa at 20°C, advantageously less than 12 kPa at 20°C; and said organic solvent A2 has a saturated vapor pressure greater than 7 Pa, advantageously greater than 8 Pa, preferably greater than 9 Pa, more preferably greater than 10 Pa at 20°C, in particular greater than 25 Pa, more particularly greater at 50 Pa, preferably greater than 100 Pa, advantageously preferably greater than 500 Pa at 20°C.
• said at least one organic solvent A2 has a flash point greater than -15°C, advantageously greater than -14°C, preferably greater than -13°C, in particular greater than -12°C .
• said at least one organic solvent A2 has a flash point lower than 90°C, advantageously lower than 85°C, preferably lower than 80°C, in particular lower than 75°C.
• said at least one organic solvent A2 can have a flash point greater than -15°C, advantageously greater than -14°C, preferably greater than -13°C, in particular greater than -12°C; and less than 90°C, advantageously less than 85°C, preferably less than 80°C, in particular less than 75°C.
• the flash point corresponds to the lowest temperature at which a combustible body emits sufficient vapor to form, with the ambient air, a gas mixture which ignites under the effect of a source of heat energy but not sufficiently so that combustion maintains itself.
• the flash point as defined here is the flash point measured in a closed cup.
• said at least one organic solvent A2 has: a donor number greater than 6 kcal/mol, advantageously greater than 7 kcal/mol, preferably greater than 8 kcal/mol, more preferably greater than 9 kcal/mol mol, in particular greater than 10 kcal/mol; and less than 30 kcal/mol, advantageously less than 29 kcal/mol, preferably less than 28 kcal/mol, more preferably less than Tl kcal/mol, in particular less than 26 kcal/mol, more particularly less than 25 kcal/mol mol, preferably less than 24 kcal/mol, advantageously preferred less than 23 kcal/mol, preferably less than 22 kcal/mol, more preferably less than 21 kcal/mol, particularly preferred less than 20 kcal/mol; a saturated vapor pressure less than 23 kPa, advantageously less than 22 kPa, preferably less than 21 kPa, more preferably less than 20 kPa at 20°C, in particular less than
• said at least one organic solvent A2 preferably has a mass water content of less than 5000 ppm, advantageously less than 4000 ppm, preferably less than 3000 ppm, more preferably less than 2000 ppm, in particular less than 1000 ppm, more particularly less than 500 ppm, preferably less than 100 ppm, advantageously preferably less than 50 ppm, preferably less than 10 ppm.
• said at least one organic solvent A2 has a mass water content greater than 1 ppb, more preferably greater than 10 ppb, in particular greater than 100 ppb. The low water content in said solvent prevents the deterioration of the other constituents present.
• Said organic solvent A2 may in particular be chosen from esters, carbonates, nitriles or dinitriles, ethers or diethers, ketones provided that it has a donor number as provided for in the present application and the saturated vapor pressure such as described in this application; and preferably the flash point as described in the present application. Combinations of these can also be used as an organic solvent.
• organic solvent A2 N,N-dimethylformamide, dimethylsulfoxide, N-methylpyrrolidone, 2-butanone, 1,2-dimethoxyethane, 1,3-dioxolane, 2, 3-butanedione, 2-methylpentan-3-one, 2- methyltetrahydrofuran, 2-pentanone, methyl cyanide, 3,3-dimethyl-2-butanone, 3-methyl-2- butanone, 3-pentanone, butyl acetate, cyclohexanone, cyclopentanone, 4-methylpentan-2-one, dibutyl ether, 1,4-dioxane, dipropyl ether, ethyl acetate, ethyl butanoate or methyl propanoate, tetrahydrofuran, N-butyl-2-pyrrolidone or a mixture of these ; in particular 2- butyl ether, 1,4-dioxane, dipropy
• Said alkali metal salt is selected from the group consisting of LiCF 3 SO 3 , LiPF 6 , LiCIO 4 , Li BF 4 , LiB(C 2 O 4 ) 2 , LiN(SO 2 F) 2 , LiN(SO 2 CF 3 ) 2 , LiN(SO 2 C 2 F 3 ) 2 , LiN(SO 2 C 2 F 5 ) 2 , LiN(SO 2 F)(SO 2 CF 3 ), LiN(SO 2 F)(SO 2 C 2 F 5 ), LiN(SO 2 CF 3 )(SO 2 C 2 F 5 ),LiAsF 6 , LiBF 2 C 2 O 4 , LiNO 3 , LiPF3(CF 2 CF 3 ) 3 , LiBETI, LiTDI, NaTDI, KTDI, NaCIO 4 , KCIO 4 , NaPF 6 , KPF 6 , NaBF 4 , KBF 4 , NaAsF 6 , KAsF 6 , NaCF 3 SO
• said alkali metal salt is selected from the group consisting of LiCF 3 SO 3 , LiPF 6 , LiCIO 4 , LiBF 4 , LiB(C 2 O 4 ) 2 , LiN(SO 2 F) 2 , LiN(SO 2 CF 3 ) 2 , LiN(SO 2 C 2 F 3 ) 2 , LiN(SO 2 C 2 F 5 ) 2 , LiN(SO 2 F)(SO 2 CF 3 ), LiN(SO 2 F)(SO 2 C 2 F 5 ), LiN(SO 2 CF 3 )(SO 2 C 2 F 5 ),LiAsF 6 , LiBF 2 C 2 O 4 , LiNO 3 , LiPF3(CF 2 CF 3 ) 3 , LiBETI, LiTDI, or a mixture of these.
• said plasticizer B2 comprises at least one ionic liquid.
• An ionic liquid is a salt that is liquid at room temperature, that is to say it has a melting temperature below 100°C under atmospheric pressure. It is formed by the association of an organic cation and an anion whose ionic interactions are sufficiently weak not to form a solid.
• this cation may comprise a C1-C30 alkyl group, such as 1-butyl-1-methylpyrrolidinium, 1-ethyl-3-methylimidazolium, N-methyl-N-propylpyrrolydinium or N-methyl- N-butylpiperidinium.
• the anions associated with them are chosen from: imides, in particular bis(fluorosulfonyl)imide and bis(trifluoromethanesulfonyl)imide; borates; phosphates; phosphinates and phosphonates, in particular alkyl phosphonates; amides, in particular dicyanamide; aluminates, in particular tetrachloroaluminate; halides (such as bromide, chloride, iodide anions); cyanates; acetates (CH3COO-), in particular trifluoroacetate; sulfonates, in particular methanesulfonate (CH3SO3-), trifluoromethanesulfonate; and sulfates, in particular hydrogen sulfate; an acrylate or a methacrylate.
• imides in particular bis(fluorosulfonyl)imide and bis(trifluoromethanesulfonyl)imide
• the anions are chosen from tetrafluoroborate (BF4-), bis(oxalato)borate (BOB-), hexafluorophosphate (PF6-), hexafluoroarsenate (AsF6-), triflate or trifluoromethylsulfonate ( CF3SO3-), bis(fluorosulfonyl)imide (FSI-), bis-(trifluoromethanesulfonyl)imide (TFSI-), nitrate (NO3-), 4,5-dicyano-2- (trifluoromethyl)imidazole (TDI- ), an acrylate or a methacrylate.
• BF4- tetrafluoroborate
• BOB- bis(oxalato)borate
• PF6- hexafluorophosphate
• AsF6- hexafluoroarsenate
• CF3SO3- triflate or trifluoromethyl
• said plasticizer B2 is a mixture of at least two ionic liquids chosen from those described above.
• said plasticizer B2 is a mixture of at least one ionic liquid and at least one solvent SI with a boiling point greater than 100°C, preferably greater than 110°C, more preferably greater than 125°C, in particular greater than 150°C, more particularly greater than 160°C.
• said SI solvent is chosen from:
• F2EC trans-4,5-difluoro-1,3-dioxolan-2-one
• EC ethylene carbonate
• PC propylene carbonate
• TEP triethyl phosphate
• - ethers such as poly ethylene glycol dimethyl ethers, in particular diethylene glycol dimethyl ether (EG2DME), triethylene glycol dimethyl ether (EG3DME), and tetraethylene glycol dimethyl ether (EG4DME).
• EG2DME diethylene glycol dimethyl ether
• EG3DME triethylene glycol dimethyl ether
• EG4DME tetraethylene glycol dimethyl ether
• Plasticizers provide improved conductivity, electrochemical stability, thermal stability, electrode compatibility and capacity retention properties compared to conventional liquid electrolytes.
• plasticizer B2 examples are the following mixtures:
• the mass ratio between the ionic liquids and the solvents forming said plasticizer B2 varies from 10:0.1 to 0.1:10 .
• the support D can be removed after the film drying step to obtain a self-supported film.
• the support D can be, by way of non-limiting example, polyethylene terephthalate, polypropylene, aluminum or aluminum coated with a polymer layer.
• the support D is a fibrous reinforcement. This makes it possible to maintain the film prepared from solution C. Generally speaking, when the support is a fibrous reinforcement, it is not removed. Fibrous reinforcement is made of any material (porous membrane, woven or non-woven) to improve mechanical properties. It may be, in a non-limiting manner, a polypropylene non-woven, a polyethylene terephthalate non-woven, a polyvinylidene fluoride non-woven or a microporous polypropylene membrane.
• the present invention provides a composition for the preparation of a solid electrolyte.
• Said composition corresponds to said solution C used in the process above.
• said composition comprises said at least one fluoropolymer Al, said at least one organic solvent A2, said at least one alkali metal salt B1 and said at least one plasticizer B2; and said at least one organic solvent A2 has a donor number greater than 4 kcal/mol, a saturated vapor pressure of 7 Pa to 24 kPa at 20°C, and preferably a flash point greater than -15°C and a content water mass less than 5000 ppm based on the total weight of the composition.
• said composition comprises from 0.75% to 18% by weight of said at least one fluoropolymer Al, from 75% to 95% by weight of said at least one organic solvent A2, from 0.1% to 7.5% by weight weight of said at least one alkali metal salt B1 and from 0.5% to 20% by weight of said at least one plasticizer B2 and a mass water content of less than 5000 ppm based on the total weight of the composition; and said at least one organic solvent A2 has a donor number greater than 4 kcal/mol, a saturated vapor pressure of 7 Pa to 24 kPa at 20°C, and preferably a flash point greater than -15°C.
• said composition comprises from 0.75% to 18% by weight of said at least one fluoropolymer Al, from 75% to 95% by weight of said at least one organic solvent A2, from 0.1% to 7.5% by weight of said at least one alkali metal salt B1 and from 0.5% to 20% by weight of said at least one plasticizer B2 and a mass water content greater than 1 ppb and less than 5000 ppm based on the total weight of the composition ; and said at least one organic solvent A2 has a donor number greater than 4 kcal/mol, a saturated vapor pressure of 7 Pa to 24 kPa at 20°C, and preferably a flash point greater than -15°C.
• said composition comprises from 2.25% to 18% by weight of said at least one fluoropolymer Al, from 75% to 85% by weight of said at least one organic solvent A2, from 0.3% to 7.5% by weight of said at least one alkali metal salt B1 and from 1.5% to 20% by weight of said at least one plasticizer B2 and a mass water content of less than 5000 ppm based on the total weight of the composition; and said at least one organic solvent A2 has a donor number greater than 4 kcal/mol, a saturation vapor pressure of 7 Pa to 24 kPa at 20°C, and preferably a flash point greater than -15°C.
• said composition comprises from 2.25% to 18% by weight of said at least one fluoropolymer Al, from 75% to 85% by weight of said at least one organic solvent A2, from 0.3% to 7.5% by weight of said at least one alkali metal salt B1 and from 1.5% to 20% by weight of said at least one plasticizer B2 and a mass water content greater than 1 ppb and less than 5000 ppm based on the total weight of the composition ; and said at least one organic solvent A2 has a donor number greater than 4 kcal/mol, a saturated vapor pressure of 7 Pa to 24 kPa at 20°C, and preferably a flash point greater than -15°C.
• Said organic solvent A2 can be as described above.
• the fluoropolymer Al can be as described above.
• Said alkali metal salt B1 can be as described above.
• Said plasticizer B2 can be as described above.
• said composition may have a mass water content of less than 5000 ppm, advantageously less than 4000 ppm, preferably less than 3000 ppm, more preferably less than 2000 ppm, in particular less than 1000 ppm, more particularly less than 500 ppm , preferably less than 100 ppm, advantageously less than 50 ppm, preferably less than 10 ppm based on the total weight of the composition.
• said composition may have a mass water content greater than 1 ppb, more preferably greater than 10 ppb, preferably greater than 100 ppb based on the total weight of the composition, in particular greater than 1 ppm.
• said composition has a solution viscosity of 100 to 50,000 cP at 10 s-1 at room temperature.
• the present invention provides a film, preferably non-porous, that is to say having a porosity less than 10%, more preferably less than 5%, in particular less than 1%.
• the porosity of the film is obtained according to the following calculation described in the publication of M.CAI, Nature Communications, 10, 2019, 4597:
• V E R represents the actual volume of the film and calculated by multiplying the surface area of the film with the thickness of the film.
• VdenseER represents the volume occupied by each of the constituents without any porosity and is calculated according to the following formula: is the sum of the volume occupied by each constituent of the film.
• said film comprises from 15 to 70% by weight of said at least one fluoropolymer Al, from 10 to 80% by weight of said plasticizer(s) B2, from 2 to 30% by weight of said salt(s). ) of alkali metal Bl, from 1 ppb to 5000 ppm of water based on the total weight of said film.
• the contents expressed here concern the film without taking into account the support D, that is to say after removal of it.
• said film also comprises from 1 ppb to 15% of said at least one organic solvent A2.
• Said film may comprise from 20 to 70% of said at least one fluoropolymer Al, advantageously from 25 to 70% of said at least one fluoropolymer Al, preferably from 30 to 70% of said at least one fluoropolymer Al.
• said film consists of from 15 to 70% by weight of said at least one fluoropolymer Al, from 10 to 80% by weight of said plasticizer(s) B2, from 2 to 30% by weight of said salt(s) of alkali metal Bl, from 1 ppb to 15% of said at least one organic solvent A2 and from 1 ppb to 5000 ppm of water based on the total weight of said film; the sum of the constituents being equal to 100.
• said film consists of 20 to 70% by weight of said at least fluoropolymer Al, of 10 to 80% by weight of said plasticizer(s) B2, of 2 to 30% by weight of weight of said alkali metal salt(s) Bl, from 1 ppb to 15% of said at least one organic solvent A2 and from 1 ppb to 5000 ppm of water based on the total weight of said film; the sum of the constituents being equal to 100.
• the content of organic solvent A2 as defined in the present application is 1 ppb to 10%, more preferably 1 ppb to 5%, in particular 1 ppb to 1%, more particularly from 1 ppb to 5000 ppm. More preferably, in this film, the content of organic solvent A2 as defined in the present application is from 10 ppb to 15%, advantageously from 10 ppb to 10%, preferably from 10 ppb to 5%, more preferably from 10 ppb at 1%, in particular from 10 ppb to 5000 ppm.
• the content of organic solvent A2 as defined in the present application is 100 ppb at 15%, advantageously 100 ppb at 10%, preferably 100 ppb at 5%, more preferably 100 ppb at 1%, in particular from 100 ppb to 5000 ppm.
• the water mass content less than 5000 ppm, advantageously less than 4000 ppm, preferably less than 3000 ppm, more preferably less than 2000 ppm, in particular less than 1000 ppm, more particularly less than 500 ppm , preferably less than 100 ppm, advantageously preferably less than 50 ppm, preferably less than 10 ppm; and the mass water content is greater than 1 ppb, more preferably greater than 10 ppb, in particular greater than 100 ppb, more particularly greater than 1 ppm.
• the film contains little or no solvent and has high ionic conductivity.
• the film is self-supporting, that is to say it can be handled without the aid of a support.
• the film is capable of being rolled up, that is to say it can be handled so that it can be wound onto a reel.
• the mass ratio between the film and the fibrous reinforcement is 1.5 to 9.
• said film has a thickness of 5 to 60 pm, preferably 5 to 30 pm, more preferably 7 pm to 20 pm.
• said film has a thickness varying from less than 20% over its entire length, preferably from less than 15% over its entire length, in particular from less than 10% over its entire length.
• the film according to the invention has an ionic conductivity ranging from 0.01 to 5 mS/cm, preferably from 0.05 to 5 mS/cm, advantageously from 0.5 to 5 mS/cm, at 25°C.
• Conductivity is measured by electrochemical impedance spectroscopy.
• the non-porous film is placed between two gold electrodes in a sealed conductivity cell and under an inert atmosphere (CESH, Biology) and electrochemical impedance spectroscopy is carried out between 1 Hz and 1 MHz with an amplitude of 10mV.
• CEH inert atmosphere
• the conductivity o is then given by the following relation: where / is the thickness of the film and S its surface area. For each composition, the conductivity value at a given temperature is obtained by averaging over at least two measurements taken on different samples.
• the film according to the invention has good electrochemical stability over the temperature range from -20°C to 80°C.
• the film maintains its properties up to 80°C and does not ignite below 130°C.
• the film according to the invention has a mechanical strength characterized by an elastic modulus, measured at 1Hz and 23°C by dynamic mechanical analysis, greater than 0.1 MPa, preferably greater than lMPa, still preferably greater than 10 MPa.
• Another object of the invention is a separator for an all-solid battery consisting, in whole or in part, of said film. In this case, the presence of said lithium salt may be optional.
• the invention also relates to an electrochemical device selected from the group: batteries, capacitor, electric double-layer electrochemical capacitor, and membrane-electrode assembly (MEA) for a fuel cell or an electrochromic device, said device comprising a separator as described.
• an electrochemical device selected from the group: batteries, capacitor, electric double-layer electrochemical capacitor, and membrane-electrode assembly (MEA) for a fuel cell or an electrochromic device, said device comprising a separator as described.
• Another object of the invention is an all-solid battery, for example a Li-ion battery, or Li-S or Li-air batteries, comprising a negative electrode, a positive electrode and a separator, in which said separator comprises a film as described above.
• said battery comprises a lithium metal anode.
• the invention also relates to an all-solid battery comprising such a film according to the present invention, preferably non-porous.
• Pellets of 20 mm diameter are cut from the polymer electrolyte film in order to measure the mass and thickness of each pellet.
• the mass of the pellets is measured using a Mettler Toledo XPE105 balance with a reading accuracy of up to 0.01 mg.
• the thickness of the pellets is measured using a Mitutoyo IDH0530 digital comparator with a precision of 0.5 ⁇ m. These pellets are taken every 10 cm along the length of the coating. The mass and thickness of these pellets are reported in Figure 1.
• Example 1 Manufacture of a film in the presence of acetone
• P(VDF-HFP) poly(vinylidene fluoride)-co-hexafluoropropylene
• P(VDF-HFP) poly(vinylidene fluoride)-co-hexafluoropropylene
• 0.47 g of LiFSI lithium bis(fluorosulfonyl)amide
• EMIM-FSI l-ethyl-3-methylimidazolium bis(fluorosulfonyl imide
• the final solution is coated on an aluminum strip 13 ⁇ m thick and 30 cm wide using a coating machine using a doctor blade set at 200 ⁇ m. aluminum strip, a coating speed of 0.5 m/min
• the coating is dried in an oven at 25°C. for 2 hours to evaporate the acetone.
• a polymer electrolyte film of approximately 1m50 in length and 10 cm in width is thus obtained.
• Acetone is not a suitable solvent for the preparation of flexible electrolyte films because the thickness and mass of the film is not homogeneous along the coating length, there is a variation of 'approximately 40% of the thickness and mass of the film between the start and the end of the coating (on 1m50 length).
• Example 2 Manufacture of a film in the presence of 2-butanone
• P(VDF-HFP) poly(vinylidene fluoride)-co-hexafluoropropylene
• P(VDF-HFP) poly(vinylidene fluoride)-co-hexafluoropropylene
• 0.47 g of LiFSI lithium bis(fluorosulfonyl)amide
• EMIM-FSI l-ethyl-3-methylimidazolium bis(fluorosulfonyl imide
• the final solution is coated on an aluminum strip 13 ⁇ m thick and 30 cm wide using a coating machine using a doctor blade set at 200 ⁇ m. aluminum strip, a coating speed of 0.5 m/min
• the coating is dried in an oven at 25°C for 2 hours to evaporate the acetone.
• a film of polymer electrolyte of approximately lm50. length and 10cm width is thus obtained.
• 2-Butanone is a suitable solvent for the preparation of flexible electrolyte films because the thickness and mass of the film is relatively homogeneous along the coating length (approximately 10% variation as illustrated in Figure 1 and in Figure 2) unlike a solvent such as acetone (approximately 50% variation over the coating length).

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Inorganic Chemistry (AREA)
• Materials Engineering (AREA)
• Composite Materials (AREA)
• Physics & Mathematics (AREA)
• Condensed Matter Physics & Semiconductors (AREA)
• Dispersion Chemistry (AREA)
• General Physics & Mathematics (AREA)
• Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
• Secondary Cells (AREA)
• Conductive Materials (AREA)
• Manufacture Of Macromolecular Shaped Articles (AREA)
• Cell Separators (AREA)
• Electric Double-Layer Capacitors Or The Like (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=86657575

Family Applications (1)

Country Status (6)

Families Citing this family (1)

Family Cites Families (5)

• 2023
  • 2023-01-26 FR FR2300731A patent/FR3145446B1/fr active Active
• 2024
  • 2024-01-25 EP EP24711934.0A patent/EP4655835A1/de active Pending
  • 2024-01-25 CN CN202480009285.7A patent/CN120530508A/zh active Pending
  • 2024-01-25 WO PCT/FR2024/050100 patent/WO2024156965A1/fr not_active Ceased
  • 2024-01-25 KR KR1020257028007A patent/KR20250139839A/ko active Pending
  • 2024-01-25 JP JP2025543236A patent/JP2026503665A/ja active Pending

Also Published As

Similar Documents

Legal Events