SOLID ELECTROLYTE

Abstract

SOLID ELECTROLYTE The present invention relates to a composition comprising zeolite crystal(s), at least one polymer binder in an amount between 0.5% and 20% by weight, and at least one ionic conductor comprising at least one lithium salt. The invention also relates to the use of said composition as a battery separator, for example, for a secondary battery, more specifically for an all-solid-state battery. Fig.: none

Description

Description Title of the invention: SOLID ELECTROLYTE This application relates to the field of electrical energy storage in batteries, more particularly in secondary batteries, and more specifically in Li-ion type secondary batteries, in particular lithium batteries with solid electrolyte, also known as all-solid batteries. Research in the field of batteries, particularly secondary batteries, and the developments made in this field during the last few decades have been and remain very important today, in terms of the number of players and the amounts involved. Rechargeable or secondary batteries appear more advantageous than primary (non-rechargeable) batteries because the associated chemical reactions that take place at the positive and negative electrodes of the battery are reversible. The electrodes of secondary cells can be regenerated multiple times by applying an electrical charge. This is why numerous electrode systems have been developed to store electrical charge. In parallel, considerable effort has been devoted to developing electrolytes capable of improving the performance of electrochemical cells. Typically, a battery comprises at least one negative electrode (or anode) coupled to a copper current collector, one positive electrode (or cathode) coupled to an aluminum current collector, a separator, and an electrolyte. The electrolyte consists, for example, of a lithium salt in the case of Li-ion batteries, generally lithium hexafluorophosphate, mixed with a solvent that is usually a mixture of organic carbonates, chosen to optimize ion transport and dissociation. A high dielectric constant promotes ion dissociation, and therefore the number of ions available in a given volume, while a low viscosity favors ion diffusion, which plays a crucial role, among other parameters, in the charge and discharge rates of the electrochemical system. Conventional Li-ion batteries contain liquid electrolytes, most often based on solvent(s), lithium salt(s), and additive(s). Given the increasing use of this type of battery in everyday consumer electronics, such as computers, tablets, and mobile phones (smartphones), as well as in the transportation sector, particularly with electric vehicles, improving safety and reducing manufacturing costs for these lithium batteries have become major challenges. Indeed, liquid electrolytes offer the advantage of good ionic conductivity, but have the disadvantage of allowing fluids to escape. (Leaks) in case of mechanical and / or chemical damage to the battery. Leaks are damaging because they most often lead to malfunction, or even failure of the battery, but also and especially to pollution and degradation through corrosion, or even ignition and / or explosion of the battery. To address this issue, and as a replacement for flammable liquid electrolytes, so-called "all-solid-state" batteries, comprising solid polymer electrolytes, some of which are SPEs (Solid Polymer Electrolytes), have been under investigation for several years. SPEs, which contain no liquid solvents, eliminate the need for flammable liquid components like those found in conventional Li-ion batteries and allow for the production of thinner and more flexible batteries. Besides SPEs, other types of all-solid-state batteries are those primarily composed of oxides or phosphates. These all-solid-state batteries have shown great potential both for small-scale applications, such as three-dimensional microbatteries, and for large-scale energy storage applications, such as for electric vehicles. Furthermore, to achieve the expected performance, the ionic conductivity of the solid electrolytes in such all-solid-state batteries must be at least equivalent to that of liquid electrolytes, i.e., on the order of 10⁻¹⁰ S cm⁻¹ at 25°C, as measured by electrochemical impedance spectroscopy. Electrochemical stability must allow the use of the electrolyte with cathode materials capable of operating at high voltages, particularly above 4.4 V, in applications requiring high energy densities, such as in the automotive sector. Finally, the solid electrolyte must exhibit a certain resistance to fire or battery runaway, meaning it must be able to operate without major problems up to at least 80°C and not ignite below 130°C. Thus, solid electrolytes have been and continue to be the subject of intense research to overcome the drawbacks listed above. Inorganic materials, such as oxides, phosphates, and ceramics, exhibit conductivities up to 10⁻¹⁰ S cm⁻¹ at 25°C (the order of magnitude of the conductivity of liquid electrolytes), but are very rigid, even brittle. Consequently, they poorly accommodate the volume changes experienced by the electrodes during cycling, which can lead to contact beading between the electrode and the solid electrolyte. Other inorganic materials, such as thiophosphates (see ACS Energy Lett., (2020), S(10), 3221-3223), offer better conductivities (up to 10⁻¹⁰ S cm⁻¹ at 25°C), which can exceed those of liquid electrolytes. However, thiophosphates are also relatively rigid and exhibit narrow electro-stability windows. chemical, but above all are very unstable in the face of water and release hydrogen sulfide (HS) in the event of accidental opening of the cell, which is not acceptable, for obvious reasons of environmental protection but also and above all for the safety of the user. Another solution under consideration is the use of polymers which, due to their high flexibility, are the most likely to accommodate variations in electrode volume during cycling and to avoid the risk of fractures at the electrode / electrolyte interface. However, some polymers suffer from somewhat limited electrochemical stability, and especially from low conductivity, often less than 10⁴ S cm⁻¹ at 25°C. In order to overcome this low ionic conductivity at room temperature, but also to further improve the mechanical properties, it has been proposed (cf. LZ Fan, H. He, CW Nan, “Tailoring inorganic-polymer composites for the mass production of solid-state batteries”, Nat. Rev. Mater., (2021), https: / / doi.org / 10.1038 / s41578-021-00320-0) by adding mineral filler materials, such as zeolites. An active filler is one that is an ionic conductor of lithium (e.g., LATP (Lithium Aluminum Titanium Phosphate), LLZO (Lithium Lanthanum Zirconium Oxide), lithium zeolites, etc.), and an inactive filler is one that is not an ionic conductor (SiO₂, AlO₄, etc.). A solid electrolyte consisting of a polymer / mineral filler composite is called a hybrid solid electrolyte. Currently, the most well-known polymers used as solid electrolyte polymers are polyethers, such as poly(ethylene oxide), also known as POE. However, these polymers have the disadvantage of crystallizing easily, especially at temperatures close to room temperature, which significantly reduces the polymer's ionic conductivity. Therefore, these polymers only allow the battery in which they are used to operate at a minimum temperature above their glass transition temperature, for example, above 60°C. Ideally, such a battery should be usable at room temperature and even at negative temperatures, typically -20°C or even lower. Furthermore, these POEs are very hydrophilic and tend to plasticize, especially in the presence of lithium salts, which reduces their mechanical stability.Finally, the poly(ethylene oxide) monomer is known to be lethal by inhalation, making the use of this product hazardous to health. The polymer electrolyte ensures mechanical stability during battery charge / discharge cycles by maintaining cohesion between the electrolyte and the electrodes and ensuring electrical insulation between the two electrodes during volume variations related to lithium insertion / deinsertion, without compromising the Ionic conductivity with excessively long chains. Until now, to solve this dimensional stability problem, particularly with POEs, it was necessary to create polymers with very long chains to achieve chain entanglement and ensure the electrode's mechanical stability. However, this increase in the polymer's molecular mass comes at the expense of chain mobility, glass transition temperature, and ionic conductivity. Therefore, to obtain a polymer that is a good ionic conductor, even at room temperature or even at low temperature, typically between -20°C and +80°C, for the purpose of obtaining a high-performance battery, it is necessary on the one hand to lower its degree of crystallinity as much as possible, so that it cannot crystallize at the operating temperature of the battery and alter the ionic conductivity, and on the other hand, that it has the lowest possible glass transition temperature, lower than the operating temperature of the battery, so that it does not have a glassy state at the operating temperature of the battery, which could also weaken the ionic conductivity. As mentioned above, another component of a conventional Li-ion battery (with liquid electrolyte) is the separator, which, located between the two electrodes, acts as both a mechanical and electronic barrier and an ionic conductor. There are several categories of separators, which can be generically referred to as: dry polymer membranes, gelled polymer membranes, and micro- or macroporous separators impregnated with liquid electrolyte. The separator market is currently dominated by the use of polyolefins (for example, those marketed by Celgard, Asahi Kasei, Toray, Sumitomo Chemical, and SK Innovation, to name only the most common), generally produced by extrusion and / or stretching. Separators must be thin, have optimal affinity for the electrolyte, and possess sufficient mechanical strength. Among the most promising alternatives to polyolefins, polymers with a better affinity for standard electrolytes have been proposed to reduce the internal resistance of the system, such as poly(vinylidene fluoride) (PVDF) and poly(vinylidene fluoride-hexafluoropropene) (P(VDF-co-HFP)). Dry polymer membranes, which do not use liquid solvents, eliminate the need for flammable liquid components like those found in conventional Li-ion batteries and allow for thinner, more flexible batteries. However, they have significantly lower properties than liquid electrolytes, particularly in terms of ionic conductivity. High conductivity is essential for high-speed operation, for example, in cell phones, for fast charging, especially in electric vehicles, and for applications such as... power, for example for power tools. Dense gel membranes also offer an alternative to liquid electrolyte-impregnated separators. Dense membranes are membranes that have no free porosity. They are swollen by the solvent, but the solvent, being strongly chemically bound to the membrane material, has lost all its solvation properties. The solute then passes through the membrane without carrying any solvent with it. In these membranes, the free spaces correspond to those left between the polymer chains and are the size of simple organic molecules or hydrated ions. The major drawback of these gel membranes is that they contain large quantities of flammable solvents.Another disadvantage is the loss of their mechanical properties after swelling, thus hindering easy handling of the separator for cell manufacturing and good resistance to mechanical stresses during battery charge / discharge cycles. US patent US5296318 describes separators based on VDF-HFP copolymers swollen in an electrolyte consisting of a lithium salt (LiPFc) and a carbonate mixture as the solvent. The examples described use Kynar Flex® 2801 and Kynar Flex® 2750 with 12% and 15% HFP by weight, respectively. More generally, this patent describes an optimal HFP content between 8% and 25% by weight. Below 8% HFP, the authors mention difficulties related to membrane implementation. Above 25%, the mechanical strength becomes insufficient after swelling. The separator manufacturing process is a solvent-based process that uses a highly volatile solvent, tetrahydrofuran. The ionic conductivity reported in examples 1 and 2 is 0.3 mS cm" and 0.4 mS cm“, respectively. This document describes the need for an additional crosslinking step for VDF-HFP copolymer separators with an HFP content exceeding 25% by weight, in order to enhance their mechanical strength after swelling. These copolymers perform satisfactorily even after heating up to 70°C. However, the copolymer, swollen by the solvent, is soluble in the liquid electrolyte at temperatures above 80°C. Melting of the electrolyte film under constant stress can lead to electrolyte leakage and an internal short circuit in the battery, resulting in rapid discharge and heating. To address this problem, US20190088916 proposes a non-porous separator containing macromolecular materials that gel upon contact with an organic solvent in the electrolytic solution, and form a polymer gel electrolyte upon addition of the electrolytic solution. This non-porous separator comprises at least one synthetic or natural macromolecular compound, and further comprises, as a matrix, at least one macromolecular material. The non-gelable polymer cannot be gelled by an organic solvent. Examples show that the non-gelable polymer is used in the form of a porous membrane that is soaked with a solution of the gelable polymer. This approach therefore requires a complex manufacturing step for the porous membrane of the non-gelable polymer, which allows control over the porosity level and the nature of the porosity (pore size and open porosity). Furthermore, the manufacturing process requires a solvent-based step to saturate the pores of the porous membrane, which has the disadvantage of using solvents and necessitates an evaporation step. International application WO2020127454 relates to the aqueous dispersion polymerization of VF2-containing monomers using RAFT / MADIX technology. More specifically, this document describes a composition containing a non-electroactive mineral filler, which may be a zeolite or silica, to act as a separator after a dispersion drying step. The work of X. Chi et al. (Nature, Vol. 592, (2021), 551-571) proposes, within the framework of Li-air-based batteries, a continuous membrane obtained by grafting carbon nanotubes (CNTs) onto a steel mesh, followed by seeded growth of LiX zeolite on the CNTs. The zeolite is preferentially generated in situ by crystalline growth directly on the CNTs. This is therefore a hybrid system combining steel, carbon nanotubes, and zeolites, the industrial-scale production of which appears relatively difficult and therefore expensive. Furthermore, the mechanical strength of this hybrid system may prove insufficient or even unsuitable, considering that cracks could lead to lithium dendrites that can cause short circuits in the battery. Other documents in the scientific and patent literature describe the presence of zeolites in Li-ion batteries, for example as a component of the separator, most often as an adsorbent for undesirable molecules such as water or acids, but also as a coating agent on the separator itself to enhance its mechanical properties. In this configuration, it is therefore a porous separator for liquid or gel electrolyte lithium-ion batteries consisting of a porous polymer film (e.g., polypropylene) with a zeolite layer on the surface. The adhesion between the porous polymer and the zeolite is generally ensured by another polymer, for example, PVDF. US patent 5728489 describes a liquid electrolyte comprising a polymer matrix whose structural integrity can be enhanced by a lithium zeolite present in an amount between 1% and 30% by weight of the liquid electrolyte. As mentioned above, liquid electrolyte batteries are unsatisfactory because they can be subject to leakage of said liquid electrolyte. Document CN104277423 describes a material intended to reduce the temperature of battery operation, said material being heat-conducting and fire-retardant and comprising a mixture of mineral fillers, including a small proportion of zeolites, said mixture being sintered with a ceramic filler. Document CN201210209283 describes a solid electrolyte comprising polyoxyethylene or a derivative thereof, a lithium salt, and an organic / mineral hybrid structure selected from a metal / organic structure (MOF), a covalent / organic structure (COF), and a zeolite / imidazole structure (ZIF). Therefore, there remains a need for all-solid-state batteries that do not present the drawbacks known today and mentioned previously. Thus, a first objective of the present invention is to provide a solid electrolyte enabling the production of all-solid-state batteries that do not present a risk of leakage in the event of mechanical damage to the battery. As another objective, the invention provides a solid electrolyte enabling the production of electrodes exhibiting satisfactory mechanical stability, and more particularly dimensional stability, in order to prevent loss of cohesion and loss of adhesion to the metallic current collector. Another objective of the invention is to provide a solid electrolyte with satisfactory conductivity even at low temperatures, typically below 80°C and down to -20°C, or even -30°C, and in particular with a conductivity equivalent to, or even greater than, that of liquid electrolytes, for example on the order of 10⁷ S emr. Yet another objective is to provide a solid electrolyte exhibiting high chemical stability under voltage (electrochemical stability), typically equal to or greater than 4.4 V. Another objective of the invention is to provide a simple and rapid, inexpensive method for producing a solid electrolyte that prevents dendrite formation, is anhydrous to eliminate any risk of degradation, and results in a system with as few volatile compounds as possible to prevent any risk of ignition. A further objective is to provide a solid electrolyte with good fire resistance, specifically a limited or even zero risk of ignition at temperatures below 120°C. A further objective is to provide a solid electrolyte with good resistance to runaway, particularly maintaining its electrical properties, especially its conductivity, under operating conditions, for example, up to temperatures of approximately 80°C.Other objectives will become apparent from the description of the present invention, which is now set forth below. Thus, the present invention relates to the field of electrochemical devices, in particular lithium-ion batteries, and more particularly all-solid-state lithium batteries. More specifically, the invention relates to a composition of a solid electrolyte intended for use in such a battery, particularly in the separator, and / or in the cathode (catholyte), and / or in the anode (anolyte). The invention also relates to a method for manufacturing such a composition, particularly for the production of an all-solid-state lithium battery. More specifically, this composition is intended for the manufacture of the separator of such a battery. The invention further relates to a battery separator comprising such a solid electrolyte composition and to methods for its manufacture. The inventors have now discovered that it is possible to achieve at least some, if not all, of the aforementioned objectives through the invention detailed below, which notably allows combining the advantages of a liquid electrolyte in terms of conductivity, and those provided by a solid electrolyte in terms of stability, absence of risk of leakage, in particular. Thus, according to a first aspect, the present invention relates to a composition comprising: A / zeolite crystal(s). B / at least one polymer binder, the quantity of said polymer binder being between 0.5% and 20% by weight, preferably between 1% and 10% by weight, relative to the total weight of the zeolite crystal(s) and the binder, and C / at least one ionic conductor comprising at least one lithium salt. Unless otherwise stated in this document, the ranges of values ​​are understood to include the limits. Thus, the invention relates to a solid electrolyte that combines zeolite crystals immobilized by a polymer binder, thereby providing the solid electrolyte with cohesion, mechanical strength, and flexibility perfectly suited for use in a battery. Furthermore, the zeolite crystals bound by the polymer binder act as reservoirs for the ionic conductor, thus ensuring electrical conductivity perfectly suited for use in a battery, particularly a secondary battery. In other words, the ionic conductor of the composition according to the invention is contained within the solid combination of zeolite crystals and polymer binder (both internally and externally). In prior art solid electrolytes, when zeolites are present, they are used to trap undesirable elements, such as water (humidity), and not to form a solid three-dimensional network capable of retaining the ionic conductor. Furthermore, in prior art, the proportion of zeolite is always low, or even very low, in the solid electrolyte. The zeolite crystals that can be used in the present invention may be crystals of one or more zeolites, identical or different. Zeolite is defined as a specific ceramic with an aluminosilicate-type skeleton. negatively charged, whose electroneutrality is ensured by one or more counter-cations. Examples of zeolite crystals perfectly suited for the present invention include zeolite crystals selected from natural or synthetic zeolites, and more particularly from natural zeolites. More specifically, the zeolites are selected from faujasites (FAU), MFI zeolites, chabazites (CHA), heulandites (HEU), Linde type A zeolites (LTA), EMT zeolites, beta zeolites (BEA), mordenites (MOR), and mixtures thereof. These different types of zeolites are clearly defined, for example, in "Atlas of Zeolite Framework Types," 5th edition, (2001), Elsevier, and are readily available to those skilled in the art commercially or easily synthesized using known methods available in the scientific and patent literature. For the purposes of the present invention, it is also possible to use hierarchically porosity homologs of the aforementioned zeolites (known as "ZPH") which are generally obtained by direct synthesis, in particular with the aid of sacrificial agents, as described for example in applications WO2015019013 or WO2007043731, or by post-processing, as described for example in WO2013106816. Preferably, the zeolite crystals are zeolite crystals selected from faujasite, and preferably faujasite of type Y, X, MSX, or LSX, and most preferably faujasite of type X, MSX, or LSX, preferably again faujasite of type MSX or LSX, and most preferably faujasite of type LSX. These different types of faujasite are characterized by their silicon / aluminum (Si / Al) molar ratio, well known to those skilled in the art, which can be measured according to the instructions given in the characterization techniques described later in this document.Faujasites of type LSX are characterized by a Si / AI molar ratio of approximately 1.00 + 0.05, Faujasites of type MSX are characterized by a Si / AI molar ratio between 1.05 and 1.15, Faujasites of type X are characterized by a Si / AI molar ratio between 1.15 and 1.50, and Faujasites of type Y are characterized by a Si / AI molar ratio greater than 1.50. For reasons of homogeneity, it is preferable to use only one type of zeolite, and preferably only one type of zeolite which is a faujasite type zeolite. The counter cation used to neutralize the zeolite can be any cation well known to those skilled in the art, and for example, a cation chosen from among the hydronium ion, organic cations (such as imidazolium, pyridinium, pyrrolidinium, and others), alkali metal cations, alkaline earth metal cations, transition metals, rare earths, in particular the lanthanum cation, the praseodymium cation, the neodymium cation, as well as mixtures of two or more of the cations listed above. For the purposes of the present invention, where the solid electrolyte is particularly suitable For the preparation of Lithium-ion batteries, zeolites are preferred in which the counter-cation is the lithium cation, possibly with the hydronium cation and / or one or more other cations of alkali or alkaline-earth metals, for example sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium cations, and mixtures thereof, the latter being preferably in negligible quantities compared to the lithium cation, for example less than 5% of the exchangeable sites according to the indications given in the characterization techniques described later. According to a preferred aspect of the present invention, the countercation of the zeolite is lithium, in an amount greater than 95%, preferably greater than 98%, preferably even greater than 99%, of the exchangeable sites, as indicated below, the other countercations necessary for the neutrality of the zeolite advantageously include alkali and alkaline earth metal cations, rare earth cations, and transition metal cations, such as titanium, zirconium, hafnium, rutherfordium, and hydronium cation as well as mixtures of the aforementioned cations. According to a particularly advantageous aspect, the composition of the present invention comprises a faujasite zeolite of type LSX in which the counter-cation is lithium in an amount greater than 95% of the exchangeable sites, this zeolite being commonly designated "LiLSX". The size and particle size distribution of the zeolite crystals present in the composition according to the invention can vary considerably. However, crystals with a size, evaluated by scanning electron microscopy (SEM) as described later in the characterization techniques, are preferred to be between 0.02 µm and 20.00 µm, preferably between 0.02 µm and 10.00 µm, preferably between 0.03 µm and 5.00 µm, and advantageously between 0.05 µm and 1.00 µm. According to a particularly preferred aspect, the particle size distribution of crystals is mono-, bi-, or multi-modal, preferably bimodal. The composition according to the present invention is a solid composition in which the polymer binder ensures the cohesion of the zeolite crystals. The polymer binder is advantageously electrochemically stable, i.e., it is not degraded or otherwise deteriorated under electrical voltage, so that the physical integrity and electrochemical properties of the battery components are maintained, particularly when subjected to the operating temperatures and voltages of the battery, typically in the range of -20°C to +80°C, and an electrical voltage greater than 4.4 V. Examples of polymers best suited to the requirements of the present invention include, but are not limited to, fluorinated polymers (PVDF, PTFE), carboxymethylcelluloses (CMC), styrene-butadiene rubbers (SBR), poly(acrylic acids) (PAAs) and their esters, polyimides, and others, preferably fluorinated polymers, including fluorinated homopolymers possibly functionalized and fluorinated copolymers possibly functionalized. Among fluoropolymers, polyvinylidene fluoride, better known by its acronym PVDF, is preferred. Vinylidene fluoride (VDF) copolymers with at least one VDF-compatible comonomer are also preferred. A "VDF-compatible comonomer" is defined as a comonomer that can be halogenated (fluorinated and / or chlorinated and / or brominated) or non-halogenated, and that is polymerizable with VDF. Non-limiting examples of suitable comonomers include vinyl fluoride, 1,2-difluoroethylene, trifluoroethylene, tetrafluoroethylene, hexafluoropropylene, trifluoropropenes and especially 3,3,3-trifluoropropene, tetrafluoropropenes and especially 2,3,3,3-tetrafluoropropene or 1,3,3,3-tetrafluoropropene, hexafluoroisobutylene, perfluorobutylethylene, pentafluoropropenes and especially 1,1,3,3,3-pentafluoropropene or 1,2,3,3,3-pentafluoropropene, perfluoroalkyl vinyl ethers and especially those of general formula Rf-O-CF=CF, Rf being an alkyl group, preferably having 1 to 4 carbon atoms (preferred examples being perfluoropropylvinyl ether and perfluoromethylvinyl ether). Comonomers may contain, in addition to fluorine, one or more chlorine and / or bromine atoms.Such co-monomers can in particular be chosen from bromotrifluoroethylene, chlorofluoroethylene, chlorotrifluoroethylene and chlorotrifluoropropene. Chlorofluoroethylene can refer to either 1-chloro-1-fluoroethylene or . 1-chloro-2-fluoroethylene. The 1-chloro-1-fluoroethylene isomer is preferred. The chloro-trifluoropropene is preferably chosen from 1-chloro-3,3,3-trifluoropropene, 2-chloro-3,3,3-trifluoropropene and mixtures thereof. According to a preferred embodiment, the comonomers are selected from vinyl fluoride, trifluoroethylene, chlorotrifluoroethylene (CTFE), the 1,2-Difluoroethylene, tetrafluoroethylene (TFE), hexafluoropropylene (HFP), perfluoro(alkyvinyl)ethers such as perfluoro(methylvinyl)ether (PMVE), perfluoro(ethylvinyl)ether (PEVE), perfluoro(propylvinyl)ether (PPVE) and mixtures thereof. In one embodiment, the VDF copolymer is a terpolymer. In another embodiment, the polymer binder is a copolymer of vinylidene fluoride (VDF) and hexafluoropropylene (HFP), more commonly known by the acronym P(VDF-co-HFP). Advantageously, said P(VDF-co-HFP) copolymer has a mass percentage of HFP greater than or equal to 5% and less than or equal to 45%. According to a preferred aspect of the present invention, the polymer binder is not soluble in the ionic conductor. According to another preferred aspect, the polymer binder is a fluorinated polymer, and preferably the polymer is chosen from PVDF, possibly functionalized, and PVDF-based copolymers, possibly functionalized. It is understood that two or more different polymer binders may be used in the composition of the present invention. The polymer binder, used in a minimal proportion relative to the quantity of zeolite crystals, as previously stated, enables cohesion between said zeolite crystals, which act as a solid reservoir for the ionic conductor of the composition of the invention. The mass fraction of zeolite crystals present in the composition according to the present invention can be measured by thermogravimetric analysis (TGA) in air, between 25°C and 450°C, with a heating rate of +5°C min. According to one embodiment, the lithium salt is chosen from the Lithium bis(fluorosulfonyl)imide (LiFSD), lithium bis(trifluoromethanesulfonyl)imide (LITFSD), lithium 2-trifluoromethyl-4,5-dicyanoimidazole (LITDI), lithium hexafluorophosphate (LiPFe), lithium tetrafluoroborate (LiBF), lithium nitrate (LiNO), lithium bis(oxalato)borate (LiBOB), and mixtures of two or more of these, in any proportion. A lithium salt particularly preferred for the purposes of the invention is LITFSI marketed by Solvay or LiFSI and / or LITDI, marketed by Arkema. LiFSI is particularly preferred, possibly in a mixture with Arkema's LiTDI. When present, the solvent used is a lithium salt solvent. Among the most suitable solvents are ionic liquids, and in particular ionic liquids formed by the association of an organic cation and an anion. Non-limiting examples of organic cations include ammonium, sulfonium, pyridinium, pyrrolidinium, imidazolium, imidazolinium, phosphonium, guanidinium, piperidinium, thiazolium, triazolium, oxazolium, pyrazolium, and mixtures thereof. In one embodiment, this cation may comprise a C,-C+O alkyl group, such as 1-butyl-1-methylpyrrolidinium (BMPYR), 1-ethyl-3-methylimidazolium (EMIM), and N- methyl-N-propylpyrrolydinium or N-methyl-N-butylpiperidinium. According to one embodiment, the anions associated with them are chosen, by way of non-limiting examples, 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 (CH;COO-) and including trifluoroacetate (CF,COO7-), sulfonates and in particular methanesulfonate (CH,SO;) or trifluoromethanesulfonate (CF:SO;), and sulfates, in particular hydrogen sulfate. In a preferred embodiment, the anions are selected from tetrafluoroborote (BF4), bis(oxalato)borate (BOB), hexafluorophosphate (PF4), hexafluoroarsenate (AsFg), triflate or trifluoromethylsulfonate (CF5SO3), bis(fluorosulfonyl)imide (FSI), bis(trifluoromethanesulfonyl)imide (TFST), nitrate (NOz), and 4,5-dicyano-2-(trifluoromethyl)imidazole (TDF). In one embodiment, said anion is selected from TDI, FSI, TFSE, PFg, BF4, NO, and BOB; and preferably, said anion is FSI. Among the preferred ionic liquids, we can cite, by way of non-limiting examples, EMIM-FSI, EMIM-TFSI, BMPYR-FSI, BMPYR-TFSI, and their mixtures. Other possible solvents include, but are not limited to: - carbonates, such as vinylene carbonate (VC) (CAS: 872-36-6), fluoroethylene carbonate or 4-fluoro-1,3-dioxolan-2-one (F1EC) (CAS: 114435-02-8), trans-4,5-difluoro-1,3-dioxolan-2-one (F2EC) (CAS: 171730-81-7), ethylene carbonate (EC) (CAS: 96-49-1), propylene carbonate (PC) (CAS: 108-32-7), - nitriles, such as succinonitrile (SN), 3-methoxypropionitrile (CAS: 110-67-8), (2-cyanoethyl)triethoxysilane (CAS: 919-31-3), - ethers, such as 1,3-dioxolane (DOL), dimethoxyethane (DME), dibutylether (DBE), poly(ethyleneglycoldimethyl ethers), including diethylene glycol dimethyl ether (EG2DME), triethylene glycol dimethyl ether (EG3DME), and tetraethylene glycol dimethyl ether (EG4DME). Of the solvents listed above, EG4DME, DOL, DME, SN, and FIEC are preferred. Mixtures of two or more of the previously defined solvents may be used, possibly in combination with one or more ionic liquids as previously defined. The quantity of solvent(s) can vary widely, for example, from 1% to 99% by weight. Thus, examples, which are not limiting and are purely illustrative, of ionic conductors include LiFSI, LiTFSI, or a mixture of LiFSI and LiTFSI, in association with one or more solvents advantageously chosen from SN, DOL, DME, FIEC and EG4DME, possibly with one or more ionic liquids, for example EMIM-FSI. Particularly preferred examples include mixtures of (LiFSI and SN), (LITFSI and SN), (LiFSI and EG4DME), (LiFSI and F1EC), (LiFSI, EG4DME and EMIM-FSI), (LiFSI, F1EC and EMIM-FSI), (LiFSI, DOL and DME), and (LiFSI, DOL, DME and SN). Examples of ionic conductors perfectly suited to the needs of the present invention include: - LiFSI (14% by weight) and succinonitrile (86% by weight), - LITFSI (20% by weight) and succinonitrile (80% by weight), - LiFSI (14% by weight) and EG4DME (86% by weight), - LiFSI (14% by weight) and F1EC (86% by weight), - LiFSI (14% weight), EG4DME (43% weight) and EMIM-FSI (43% weight), - LiFSI (14% weight), F1EC (43% weight) and EMIM-FSI (43% weight), - LiFSI (14% by weight), DOL (43% by weight) and DME (43% by weight), - LiFSI (14% by weight), DOL (21.5% by weight), DME (21.5% by weight) and SN (43% by weight). As explained below, the ionic conductor is impregnated within the solid (zeolite crystals + polymer binder). The amount of ionic conductor that can be impregnated within this solid can vary considerably, depending, but not limited to, on the type of zeolite and the size of the zeolite crystals, the zeolite-to-binder weight ratio, and the nature and quantity of each component of the ionic conductor, among other factors. This amount is generally between 5% and 400%, preferably between 5% and 300%, and even more preferably between 10% and 200%, by weight relative to the solid (zeolite crystal(s) + polymer binder(s)). The composition according to the invention is therefore a solid electrolyte characterized by the presence of an ionic conductor (liquid) that impregnates a collection of zeolite crystals held together by at least one polymer binder. According to one embodiment of the present invention, the quantity of zeolite crystals represents at least 55%, preferably at least 60%, more preferably at least 80%, and advantageously at least 90%, more preferably at least 95% by weight, of the solid (zeolite + binder), not including the ionic conductor. Non-limiting examples of compositions according to the present invention include compositions comprising: A / FAU type zeolite crystals, advantageously LSX zeolite crystals preferably exchanged with lithium, B / at least one fluorinated polymer binder, preferably PVDF, in an amount between 0.5% and 20% by weight, preferably between 1% and 10% by weight, relative to the total weight of the zeolite crystal(s) and the binder, and C / at least one ionic conductor comprising at least one lithium salt, advantageously LiFST, at least one solvent advantageously chosen from SN, DOL, DME, FIEC and EG4DME, possibly with at least one ionic liquid, for example EMIM-FSI. By way of non-limiting examples of composition according to the present invention, one can quote: - Zeolite LILSX (45% by weight), PVDF (5% by weight) and ionic conductor [50% by weight, composed of LiFSI (14% by weight) and succinonitrile (86% by weight)], - Zeolite LILSX (58.5% by weight), PVDF (6.5% by weight) and ionic conductor [35% by weight, composed of LiFSI (14% by weight) and succinonitrile (86% by weight)], - Zeolite LILSX (61.7% by weight), PVDF (3.3% by weight) and ionic conductor [35% by weight, composed of LiFSI (14% by weight) and succinonitrile (86% by weight)], - Zeolite LILSX (61.7% wt.), PVDF (3.3% wt.) and ionic conductor [35% wt., composed of LiTFSI (20% wt.) and succinonitrile (80% wt.)], - Zeolite LiLSX (61.7% wt.), PVDF (3.3% wt.) and ionic conductor [35% wt., composed of LiFSI (14% wt.) and EG4DME (86% wt.)], - Zeolite LILSX (61.7% by weight), PVDF (3.3% by weight) and ionic conductor [35% by weight, composed of LiFSI (14% by weight) and F1IEC (86% by weight)], - Zeolite LILSX (61.7% by weight), PVDF (3.3% by weight) and ionic conductor [35% by weight, composed of LiFSI (14% by weight), EMIM-FSI (43% by weight) and EG4DME (43% by weight)], - Zeolite LILSX (61.7% by weight), PVDF (3.3% by weight) and ionic conductor [35% by weight, composed of LiFSI (14% by weight), EMIM-FSI (43% by weight) and F1EC (43% by weight)], - Zeolite LiLSX (61.7% by weight), PVDF (3.3% by weight) and ionic conductor [35% by weight, composed of LiFSI (14% by weight), DOL (21.5% by weight), DME (21.5% by weight) and EG4DME (43% by weight)]. The composition of the present invention has the advantage of being a solid electrolyte while exhibiting good flexibility and offering mechanical strength perfectly suited for use in batteries, particularly lithium-ion batteries. It has been discovered, quite surprisingly, that the conductivities of the compositions of the present invention are of the same order of magnitude, or even identical, to those of the ionic conductors impregnated in the solid [zeolite + binder]. The composition according to the invention therefore offers an excellent compromise between optimized mechanical properties (solid and flexible electrolyte) and maximum ionic conductivity. The composition of the present invention can be prepared by imbibing the system (zeolite crystals + polymer binder) with the ionic conductor, or alternatively by imbibing the zeolite crystals with the ionic conductor, then adding the polymer binder. According to one embodiment, the process for preparing the composition according to the present invention comprises: a) the mixing of zeolite crystals with at least one polymer binder, in the solid state, b) formatting according to the desired appearance and size, c) heating and pressurizing the homogenized and formed assembly in order to soften the polymer binder, d) maintaining temperature and pressure until cohesion is achieved between the Zeolite crystals and the binder, and e) cooling until the binder hardens. The mixing in step a) can be carried out using any conventional technique well known to those skilled in the art for mixing solids. The shaping to the desired appearance and size in step b) can be achieved, for example, by extrusion or any other technique also well known to those skilled in the art. The heating in step c) must be carried out at a temperature sufficient to allow the polymer binder to soften and adhere to the zeolite crystals. The heating temperature is typically about 5°C to 10°C above the melting or softening point of the polymer binder. The applied pressure depends on many factors, including the quantity of crystals relative to the binder, the size of the zeolite crystals, the nature of the binder, and others, and is typically between 10 MPa and 2000 MPa, generally between 100 MPa and 1500 MPa. The imbibition step, whether carried out on the zeolite crystals or on the article obtained after cooling in step e) of the process described above, can be carried out by any means known per se, and for example by immersion, partial or total, and preferably total, in the ionic conductor, for a variable duration depending on the nature and quantity of the different components of the composition of the invention, and typically for a duration ranging from a few minutes to a few hours. The composition of the invention can be in various forms and sizes, for example, and purely by way of illustration, in the form of films or agglomerates of various morphologies. For example, when the composition is used as an all-solid battery separator, the composition is in film form. The composition of the present invention is therefore in the form of a solid comprising zeolite crystals soaked in a solid electrolyte, said crystals being immobilized by a polymer binder. The composition of the invention behaves like a reservoir containing a liquid electrolyte, without any possibility of electrolyte leakage. The flammability of the electrolyte is thus greatly reduced. The polymer binder which immobilizes the zeolite crystals thus gives the solid composition of the invention mechanical resistance, but also flexibility, which is perfectly suited for use as a solid electrolyte, for example in Lithium-ion type batteries. The solid composition according to the invention thus behaves like an electrolyte solid in which the pores of the zeolites and the interstices between the crystals are filled, at least partially or totally, by a liquid ionic conductor, the ions being able to circulate freely in said pores and interstices, without the solid electrolyte exhibiting any electrolyte leakage. The composition according to the invention, which is a solid electrolyte, demonstrates performance at least equivalent to that of a liquid electrolyte in terms of ionic conductivity and electrochemical stability. Indeed, it has been observed that the composition of the invention offers entirely satisfactory and suitable electrochemical stability, exhibiting very good resistance to oxidation and reduction when an electrical voltage is applied. Thus, one of the additional advantages of the composition according to the invention is that it provides electrochemical performance at least equal to that of liquid electrolytes while improving safety. Furthermore, the composition according to the invention surprisingly exhibits resistance to the growth of dendrites, typically lithium dendrites, which can be detrimental to battery operation by causing short circuits. Thus, the composition of the invention can be used not only in a battery with an anode, for example, made of graphite, graphite / silicon, or silicon, but also with a metallic anode, such as lithium metal, which notably allows for an increase in energy density compared to conventional Li-ion technologies. Due to the numerous advantages offered by the composition of the invention, the composition according to the invention can be very advantageously used as a solid electrolyte in many electrochemical devices, such as, by way of non-limiting example, batteries, capacitors, electrochemical double-layer capacitors, membrane-electrode assemblies (MEAs) for fuel cells, or electrochromic devices. More specifically, and as indicated above, the solid electrolyte of the invention can be used as a separator, and / or in the cathode (catholyte), and / or in the anode (anolyte), particularly in a battery, more particularly a secondary battery, typically an all-solid-state battery, and even more particularly an all-solid-state lithium-ion battery. In yet another aspect, the invention relates to the use of the composition described above as a separator for an all-solid-state battery. In yet another aspect, the invention relates to a separator, particularly for a Li-ion secondary battery, comprising a composition according to the present invention. In a preferred embodiment, the composition according to the present invention constitutes the separator for an all-solid-state battery. The composition according to the present invention can also be used as an anolyte or catholyte in a battery, for example, a Li-ion secondary battery, and more particularly, an all-solid-state battery. According to one embodiment of the separator of the invention, it is in the form of a film. The separator advantageously has a thickness, measured with a Palmer micrometer, of between 5 µm and 500 µm, preferably between 5 µm and 100 µm, preferably still between 5 µm and 50 µm, and even more preferably between 5 µm and 20 µm. Finally, the invention aims to provide rechargeable Li-ion batteries comprising such a separator. The invention also relates to a battery comprising at least one composition including zeolite crystal(s) as defined above, said battery being an all-solid-state battery or a secondary Li-ion battery. In the battery according to the invention, said at least one composition including zeolite crystal(s) as defined above constitutes the separator and / or the anolyte and / or the catholyte of said battery, preferably the separator. Characterization techniques The physical properties of zeolites are evaluated using methods known to those skilled in the art, the main ones of which are listed below. Grain size of zeolite crystals: The number-average diameter of zeolite crystals is estimated by scanning electron microscopy (SEM). To estimate the size of the zeolite crystals in the samples, a series of images are taken at a magnification of at least 5000x. The diameter of at least 200 crystals is then measured using dedicated software, such as Smile View from LoGraMi. The accuracy is approximately 3%. Chemical analysis of zeolites - Si / Al ratio and exchange rate: An elemental chemical analysis of the zeolite is carried out according to the X-ray fluorescence chemical analysis technique as described in the standard NF EN ISO 12677: 2011 on a wavelength dispersive X-ray spectrometer (WDXRF), for example Tiger S8 from the company Bruker. X-ray fluorescence is a non-destructive spectral technique that exploits the photoluminescence of atoms in the X-ray range to determine the elemental composition of a sample. Excitation of atoms, generally by an X-ray beam or by electron bombardment, generates specific radiations after the atom returns to its ground state. After calibration, a measurement uncertainty of less than 0.4% by weight is typically obtained for each oxide. Other analytical methods are illustrated, for example, by atomic absorption spectrometry (AAS) and inductively coupled plasma atomic emission spectrometry (ICP-AES), described in the NF EN ISO standards. 21587-3 or NF EN ISO 21079-3 on a device of type for example Agilent 5110. Using conventional methods and after calibration, a measurement uncertainty of less than 0.4% by weight is obtained for each oxide (SiO₂, Al, O₃) as well as for the various oxides (such as those derived from exchangeable cations, for example, sodium). The ICP-AES method is particularly well-suited for measuring lithium content. Thus, the elemental chemical analyses described above allow verification of the Si / Al molar ratio of the zeolite used. In the description of the present invention, the measurement uncertainty of the Si / Al ratio is ±5%. The Si / Al ratio of the zeolite present in the adsorbent material can also be measured by solid-state Nuclear Magnetic Resonance (NMR) spectroscopy of silicon. The quality of ion exchange is related to the number of moles of the cation in question in the zeolite crystals after exchange. More precisely, the percentage of a cation relative to the number of exchangeable sites is estimated by evaluating the ratio between the equivalent number of moles of said cation (requiring electronic neutrality) and the total number of exchangeable sites, which is equal to the total number of aluminum atoms present in the zeolite framework. The respective quantities of each cation are determined by chemical analysis of the corresponding cations. The following examples illustrate, in a non-limiting way, the scope of the invention. Example 1: Preparation of a solid electrolyte for a Li-ion battery separator A mixture is prepared containing 5 wt% PVDF with a melting point below 175°C (Kynar® from Arkema) and 95 wt% lithium zeolite LILSX (NaLSX crystals prepared according to document EP2244976 and then lithium exchanged by sodium cation exchange in a lithium chloride solution, using conventional techniques). The average number diameter of LiLSX crystals is 5.5 µm. The binder and zeolite crystal mixture is ground in a mortar, then compressed in a pelletizer at 3000 kg cm⁻¹ and 160°C for 15 minutes. The resulting 250 µm thick film is then soaked by immersion for 30 minutes in a solution composed of 80% by weight succinonitrile and 20% by weight LiTFSI (available from Gotion). The film is then drained and weighed to determine the mass increase after soaking, which is approximately 55%. Example 2: Measurement of the ionic conductivity of an all-solid separator Ionic conductivity (0) is evaluated by electrochemical impedance spectroscopy by placing the solid electrolyte between the two gold electrodes of a sealed conductivity cell under an inert atmosphere (CESH, Bilogic). A measurement is performed on a solid electrolyte (SE1) composed of a zeolite impregnated with an ionic conductor A composed of LiTFSI (20 wt.) and succinonitrile (80 wt.). The The results are presented in Table 1. [Table 1] [Solid ether | Composition] |SE1 0 @ 25°C (mS em!) [0.26 Zeolite LiLSX (61.7% by weight), PVDF (3.3% by weight) and ionic conductor A (35% by weight) Example 3: Measurement of the thermal stability of an all-solid separator. To verify that the properties of the all-solid separator are not degraded, at least up to 80°C, ionic conductivity measurements are performed as described in Example 2. After introducing the solid electrolyte into the CESH cell, a first conductivity measurement is taken at 25°C (61). The CESH cell is then gradually heated to 80°C and maintained at 80°C for 1 hour. The temperature is then gradually lowered to 25°C, and a second conductivity measurement is taken at 25°C (0). Measurements are thus performed on the solid electrolytes SE1 and SE2 defined in Example 2. The results are presented in Table 2. [Tables2] [Solid electrolyte] |Composition |SE1 0, @ 25°C |o, @ 25°C (mS cm!) (mS cm!) weight), |0.26 0.26 Zeolite LiLSX (61.7% by weight), PVDF (3.3% by weight) and ionic conductor A (35% by weight) The conductivity of the electrolyte at 25°C is maintained after being heated to 80°C for 1 hour. This shows that there has been neither degradation of the material nor leakage of the ionic conductor.

Claims

Demands

1. Composition comprising: A / zeolite crystals, B / at least one polymer binder, the quantity of said polymer binder being between 0.5% and 20% by weight, preferably between 1% and 10% by weight, relative to the total weight of the zeolite crystal(s) and binder, and C / at least one ionic conductor comprising at least one salt of lithium.

2. Composition according to claim 1, wherein the crystals of Zeolite(s) are zeolite crystals selected from faujasites (FAU), MFI zeolites, chabazites (CHA), heulandites (HEU), Linde type A (LTA) zeolites, EMT zeolites, beta zeolites (BEA), mordenites (MOR) and their mixtures.

3. Composition according to claim 1 or claim 2, in which zeolite crystals are zeolite crystals chosen from faujasite of type Y, X, MSX, LSX, in such a way as to preferred fact, faujasite type X, MSX or LSX, preferably still Faujasite of type MSX or LSX and in a completely preferred manner LSX type faujasite.

4. Composition according to any one of the preceding claims, in which the zeolite crystals are zeolite crystals whose counter-cation is chosen from among the hydronium ion, the or- cations organics, the cations of alkali metals, of alkaline earth metals, transition metals, rare earth elements, and mixtures of two or several of them.

5. Composition according to any one of the preceding claims, in which the zeolite crystals are zeolite crystals whose counter-cation is the lithium cation, possibly with the hydronium cation and / or one or more other metal cations alkali or alkaline earth metals, for example sodium cations, of potassium, rubidium, cesium, magnesium, calcium, and strontium, barium, and mixtures thereof.

6. Composition according to any one of the preceding claims, in which the size of the zeolite crystal(s) is between between 0.02 µm and 20.00 µm, preferably between 0.02 µm and 10.00 µm, preferably still between 0.03 µm and 5.00 µm, and advantageously between 0.05 µm and 1.00 µm.

7. Composition according to any one of the preceding claims, in which said at least one polymer binder is chosen from the Fluorinated polymers, carboxymethylcelluloses, rubbers styrene-butadiene, poly(acrylic acids) and their esters, po- lyimides, preferably among fluorinated polymers, including ho- fluorinated mopolymers, possibly functionalized, and copolymers fluorinated, possibly functionalized.

8. Composition according to any one of the preceding claims, in which said at least one polymer binder is chosen from the poly(vinylidene fluoride), vinylidene fluoride copolymers with at least one comonomer compatible with vi- fluoride nylidene.

9. Composition according to any one of the preceding claims, in which the lithium salt is chosen from the lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide), the lithium 2-trifluoromethyl-4,5-dicyanoimidazole, lithium hexafluorophosphate, lithium tetrafluoroborate, lithium nitrate, lithium bis(oxalato)borate, as well as mixtures of two or more of them, in any proportions, of preference chosen from bis(trifluoromethanesultonyl)imide of lithium), lithium bis(fluorosulfonyl)imide and mixtures with Lithium 2-trifluoromethyl-4,5-dicyanoimidazole.

10. Composition according to any one of the preceding claims, in which the amount of ionic conductor is generally between 5% and 400%, preferably between 5% and 300%, of preference still between 10% and 200%, by weight relative to the solid (zeolite crystal(s) + polymer binder(s)).

11. | Composition according to any one of the preceding claims, in which the ionic conductor comprises LiFSI, LiTFSI, or a mixture of LiFSI and LITFSI, in association with one or more solvents advantageously chosen from SN, DOL, DME, the F1EC and EG4DME, possibly with one or more liquids JONIQUES.

12. Composition according to any one of the preceding claims, including: A / FAU-type zeolite crystals, advantageously LSX zeolite crystals, preferably lithium exchanged, B / at least one fluorinated polymer binder, preferably PVDF, in quantity between 0.5% and 20% by weight, preferably between 1% and 10% by weight, relative to the total weight of the zeolite crystal(s) and the binding, and C / at least one ionic conductor comprising at least one salt of lithium, advantageously LiFSI, at least one solvent advantageously chosen from the SN, the DOL, the DME, the FIEC and the EG4DME, even- temporarily with at least one ionic liquid.

13. Use of a composition according to any one of the claims previous indications, as a separator, and / or in the cathode (catholyte), and / or in the anode (anolyte), particularly in a battery, more specifically a secondary battery, typically a battery all solid, and more specifically a Lithium-ion battery solid.

14. Use according to claim 14, as a battery separator any solid in the form of a film with a thickness between 5 µm and 500 µm, preferably between 5 µm and 100 µm, preferably still between 5 µm and 50 µm, and even more preferably between 5 yumet 20 um.