FR3157000A1 - COMPOSITION AND SOLID ELECTROLYTE - Google Patents

Abstract

The invention relates to a composition consisting essentially of at least one first inorganic precursor, at least one second inorganic precursor, said inorganic precursors being dispersed in at least one organic polymer, and of which - The at least one first inorganic precursor is selected from the family of alkoxymetalloids of formula M-(OR1)n with n ranging from 1 to 4 and R1 selected from hydrogen, alkyl, aryl, and/or alkenyl groups, and M a metalloid element, - The at least one second inorganic precursor is selected from (R2-O)4-m-M-(R3)m with m ranging from 1 to 3, R2 selected from hydrogen, alkyl, aryl, and/or alkenyl groups, R3 selected from alkyl, aryl, and/or alkenyl groups and comprising a hydrolyzable function and M a metalloid element, and - The at least one organic polymer comprises at least one chain lateral Figure to be published with the abstract: Figure 1

Description

COMPOSITION AND SOLID ELECTROLYTE

The invention relates to the field of electrochemistry and more specifically to solid electrolytes. In particular, the invention relates to a composition, preferably a composition for a solid electrolyte.

Furthermore, the invention relates to a solid electrolyte.

Below we describe the known prior art from which the invention was developed.

In the field of electrochemistry, there are different types of electrochemical cells. An electrochemical cell usually consists of a positive electrode and a negative electrode that are separated by a separator in the presence of electrolyte. Thanks to the reactions that occur at the electrodes, the electrochemical cell is able to produce electrical energy. To prevent the electrodes from coming into contact with each other and creating a short circuit, they can be separated by a separator immersed in a liquid electrolyte or directly separated by a solid electrolyte.

The electrolyte also allows the transfer of ions from one electrode to the other, reflecting a certain ionic conductivity and ensuring the operation of the electrochemical cell.

A liquid electrolyte, commonly known in lithium-ion (Li-ion) systems, comprises a solution of a lithium salt dissolved in a solvent, for example from the carbonate family, such as ethylene carbonate (EC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC) or propylene carbonate (PC).

These liquid electrolytes are of particular interest in industry because they offer good ionic conductivity of lithium ions.

However, liquid electrolytes have a low viscosity, which increases the risk of electrolyte leakage from the cell. In addition, the presence of carbonate results in a high risk of flammability, which reduces safety.

Also, alternatives to liquid electrolytes have been developed, including solid electrolytes where the liquid electrolyte is replaced by a solid compound.

For example, the solid electrolyte can be an oxide, a ceramic-type oxide, a sulfide, or a polymer. The solid electrolyte can include a salt if necessary. In Li-ion batteries, these are lithium salts.

Ceramics allow lithium to pass through and can act as a separator, eliminating the need for a microporous separator film. However, their brittleness has hampered their development and application in industry.

Solid oxides have high mechanical strength and chemical stability, but they generally require high-temperature sintering, which weakens the structure. Furthermore, their ionic conductivity currently remains low, particularly due to grain boundary resistance.

Finally, solid polymer electrolytes have attractive properties in industry, particularly due to their economic potential and ease of production. In addition, they have little risk of leakage and little risk of ignition. However, they have reduced ionic conductivity, particularly at room temperature.

To avoid the low conductivity of solid polymer electrolytes, gel-polymer electrolytes have been developed. In this case, the liquid electrolyte (solvent and salt) is immobilized within a polymer matrix comprising one or more polymers capable of forming a gel.

The solvent and salt allow the electrolyte to offer conductivity close to that of liquid electrolytes, while the polymer matrix provides a solid structure. However, they have poor mechanical properties, which makes their use difficult.

Some solid and gel electrolytes can be made from acid- or base-catalyzed sol-gel reactions.

Indeed, as is known per se, a so-called sol-gel reaction is a synthesis of oxides based on the formation of oxo bridges by a succession of hydrolysis and condensation reactions. The first steps allow the production of a colloidal "sol" solution and the following ones the production of a "gel" gel.

Two synthetic routes predominate: the inorganic route from metal salts in aqueous solution and the polymeric route from metal or metalloid alkoxides in organic solution. The hydrolysis reaction can be initiated by adding water (alkoxy route) or by changing the pH (inorganic route). The development of oxide-polymer networks takes place from precursors, generally metal alkoxides. The hydrolysis and condensation of metal alkoxides can be considered as a nucleophilic substitution of the alkoxy by the hydrolyzed species. Thus, the reactions proceed according to:

(1) M-OR + H ₂ O M-OH + ROH conversion of alkoxy functions into hydroxy which allows the generation of reactive M-OH functions

(2) M-OH + HO-M MOM + H ₂ O condensation with oxolation and water release

(3) M-OR + HO-M M-O-M + ROH condensation with alkoxolation and release of an alcohol.

With M a metal or metalloid such as silicon, with R an organic group of general formula CnH2n+1.

In the specific case of silicon alkoxides, water is introduced in alcoholic solution with precursors, the most common of which are TMOS or TEOS (for tetramethoxysilane and tetraethoxysilane respectively). The hydrolysis step is particularly slow, so a catalyst is always used. This catalyst can be an acid or a base.

Furthermore, the competition between hydrolysis and condensation is controllable thanks to the pH of the reaction.

In an acidic medium, hydrolysis is faster than condensation, the gel obtained, called "polymeric gel", comprises a polymeric silica network trapping the solvent and molecules still in solution (in particular the catalyst and the catalysis products).

In a basic medium, condensation is generally faster and leads to porous gels called "colloidal gel" whose negatively charged silica network leaves the molecules in suspension (we also find the catalyst and catalysis product).

Thus, it may become necessary to control the reaction kinetics to add chelators, again acid or base such as acetic acid for example.

Furthermore, the gel obtained by acid or basic catalysis also includes solvents and precursors which have not necessarily reacted.

Thus the pH and the catalysts influence the sol-gel reaction and the gel obtained.

However, catalysts and their reaction products in the solvent and/or gel generate high reactivity that greatly reduces the electrochemical stability of the electrolytes. In addition, the products of catalysis (acid or base) can cause unwanted oxidation side reactions on some of the functional groups. This can result in the presence of toxic or corrosive species or even increase the dissolution of the solid electrolyte and reduce its lifetime. The high reactivity of both the base or acid and the metal will also greatly limit the applicable reaction and/or processing solvent media.

These reactive bases or acids and metals are also generally sensitive to moisture and air, requiring expensive and complex manufacturing processes.

Similarly, current processes do not include complex and expensive purification to remove these catalysts and their reaction products that can remain trapped in the gel and reduce its mechanical and electrochemical properties. Indeed, after obtaining the gel, it is dried (different types of drying exist) which allows the evaporation of the solvents or alcohols formed, but not the catalysts and/or their reaction products that remain harmful to the operation of an electrochemical system.

Finally, there are also sol-gel reactions involving mineral and organic species in order to obtain so-called "hybrid" electrolytes. These electrolytes are obtained from mixed precursors such as organo-alkoxysilanes which include both hydrolyzable Si-OR functions for the formation of the silica network and Si-R functions attached to the silica skeleton.

Again, two routes predominate: post-addition of ceramic particles within the polymer matrix or in situ generation of the inorganic part using ceramic precursors such as TEOS.

However, the hydrolysis reaction remains initiated by acid or basic catalysts, for example HCl or NaOH, and therefore generates the same drawbacks as the sol-gel routes of solid or gelled electrolytes due to the residual presence of reaction products.

Thus, there is a need for new compositions and processes capable of doing without the use of traditional catalysts (acid or base).

The invention aims to overcome the drawbacks of the prior art. In particular, the invention aims to propose a composition not comprising a traditional acid and/or basic catalyst and making it possible to meet the needs of the field of electrochemistry.

Thus, the invention aims to provide a solid electrolyte, said solid electrolyte not comprising any acid or basic catalyst residue and making it possible to meet the requirements of the field of electrochemistry, namely, in particular good ionic conductivity and good mechanical and electrochemical properties (i.e. electrochemical stability). In the present invention, the catalyst is a component of the final system and therefore no longer has to be eliminated.

The invention aims to overcome the disadvantages of the prior art. The following presents a simplified summary of selected aspects, embodiments and examples of the present invention for the purpose of providing a basic understanding of the invention. However, this summary does not constitute an exhaustive overview of all aspects, embodiments and examples of the invention. Its sole purpose is to present selected aspects, embodiments and examples of the invention in a concise form as an introduction to the more detailed description of the aspects, embodiments and examples of the invention which follow the summary.

• L’au moins un premier précurseur inorganique est sélectionné parmi la famille des alcoxymétalloïdes de formule M-(OR₁)_navec n allant de 1 à 4 et R₁sélectionné parmi hydrogène, groupement alkyle, aryle, et/ou alkenyle, et M un élément métalloïde,
• L’au moins un deuxième précurseur inorganique est sélectionné parmi des (R₂-O)_4-m-M-(R₃)_mavec m allant de 1 à 3, R₂sélectionné parmi hydrogène, groupement alkyle, aryle et/ou alkenyle, R₃sélectionné parmi groupement alkyle, aryle et/ou alkenyle et comprenant une fonction hydrolysable et M un élément métalloïde, et
• L’au moins un polymère organique comprend au moins une chaine latérale.

The invention relates in particular to a composition consisting essentially of at least one first inorganic precursor, at least one second inorganic precursor, said inorganic precursors being dispersed in at least one organic polymer, and of which

• The at least one first inorganic precursor is selected from the family of alkoxymetalloids of formula M-(OR ₁ ) _n with n ranging from 1 to 4 and R ₁ selected from hydrogen, alkyl, aryl, and/or alkenyl group, and M a metalloid element,
• The at least one second inorganic precursor is selected from (R ₂ -O) _4-m -M-(R ₃ ) _m with m ranging from 1 to 3, R ₂ selected from hydrogen, alkyl, aryl and/or alkenyl group, R ₃ selected from alkyl, aryl and/or alkenyl group and comprising a hydrolyzable function and M a metalloid element, and
• The at least one organic polymer comprises at least one side chain.

Such a composition makes it possible to do without the use of traditional catalysts (acid or basic) while still meeting the needs of the field of electrochemistry.

The composition according to the invention makes it possible to avoid the need for purification or elimination of catalysts and/or reaction products.

Furthermore, the composition according to the invention allows the combination and preferably the dispersion of inorganic precursors within at least one organic polymer. The composition allows inorganic precursors to be intimately mixed with at least one organic polymer. The composition allows different applications and in particular applications in electrochemistry. In addition, such a composition allows the stabilization of the components and in particular the ionic components within the at least one organic polymer.

• l’au moins un polymère organique est un polymère étoilé,
• l’au moins un polymère organique est sélectionné parmi polyoxyde ou copolyoxyde d’alkylène (s), polyméthacrylate, polyacrylate, polysaccharide, polyacrylonitrile, polyimide et/ou des (co) polymères de VF2 (pour fluorure de vinyldiène), leur dérivé et/ou leur mélange,
• l’au moins un deuxième précurseur inorganique est sélectionné parmi TESPSA, précurseur inorganique comprenant de préférence une fonction hydrolysable et un groupement alkyl succinique,
• l’élément métalloïde est sélectionné parmi Si et/ou B,
• elle comprend en outre au moins un sel, de préférence un ou plusieurs sels de lithium,
• elle comprend en outre des particules inorganiques.

According to other optional features of the composition, the latter may optionally include one or more of the following features, alone or in combination:

• the at least one organic polymer is a star polymer,
• the at least one organic polymer is selected from polyoxide or copolyoxide of alkylene(s), polymethacrylate, polyacrylate, polysaccharide, polyacrylonitrile, polyimide and/or (co)polymers of VF2 (for vinyldiene fluoride), their derivative and/or their mixture,
• the at least one second inorganic precursor is selected from TESPSA, an inorganic precursor preferably comprising a hydrolyzable function and a succinic alkyl group,
• the metalloid element is selected from Si and/or B,
• it further comprises at least one salt, preferably one or more lithium salts,
• It also includes inorganic particles.

According to a second subject, the invention relates to a use of the composition according to the invention for forming a solid electrolyte. Such use makes it possible to facilitate the formation of a solid electrolyte (absence of purification and/or elimination of catalyst, reaction product).

• L’au moins un premier précurseur inorganique est sélectionné parmi la famille des alcoxymétalloïdes de formule M-(OR₁)_navec n allant de 1 à 4 et R₁sélectionné parmi hydrogène, groupement alkyle, aryle, et/ou alkenyle, et M un élément métalloïde,
• L’au moins un deuxième précurseur inorganique est sélectionné parmi des (R₂-O)_4-m-M-(R₃)_mavec m allant de 1 à 3, R₂sélectionné parmi hydrogène, groupement alkyle, aryle et/ou alkenyle, R₃sélectionné parmi groupement alkyle, aryle et/ou alkenyle et comprenant une fonction hydrolysable et M un élément métalloïde, et
• L’au moins un polymère organique comprend au moins une chaine latérale.

According to a third object, the invention relates to a solid electrolyte characterized in that it comprises at least one inorganic network dispersed in at least one organic polymer, said inorganic network corresponding to a condensation between at least one first inorganic precursor and at least one second inorganic precursor,

• The at least one first inorganic precursor is selected from the family of alkoxymetalloids of formula M-(OR ₁ ) _n with n ranging from 1 to 4 and R ₁ selected from hydrogen, alkyl, aryl, and/or alkenyl group, and M a metalloid element,
• The at least one second inorganic precursor is selected from (R ₂ -O) _4-m -M-(R ₃ ) _m with m ranging from 1 to 3, R ₂ selected from hydrogen, alkyl, aryl and/or alkenyl group, R ₃ selected from alkyl, aryl and/or alkenyl group and comprising a hydrolyzable function and M a metalloid element, and
• The at least one organic polymer comprises at least one side chain.

A solid electrolyte according to the invention makes it possible to exhibit good mechanical and electrical properties, particularly ionic conductivity, as well as an improved electrochemical stability voltage window. Indeed, the electrolyte according to the invention is not liquid while being manipulable and stretchable without breaking or collapsing. Advantageously, the solid electrolyte exhibits good homogeneity of the structure of the electrolyte, preferably at the submicron scale, and good purity (absence of catalyst and residues).

In addition, the solid electrolyte according to the invention also has good stability due to the absence of reaction products of acidic or basic catalysts. In addition, the solid electrolyte according to the invention does not include any toxic, corrosive or dissolution-increasing species. The presence of an inorganic fraction improves the electrochemical stability voltage window.

According to other optional characteristics of the electrolyte according to the invention, the latter may optionally include one or more of the following characteristics, alone or in combination: the at least one organic polymer comprises a condensation of the at least one first inorganic precursor with the at least one second inorganic precursor in its hydrolyzed form to form an inorganic network, said inorganic network condensing with the at least one organic polymer to form an organic/inorganic hybrid network.

According to a fourth object, the invention relates to a use of a solid electrolyte according to the invention in electrochemical devices of the accumulator, battery, capacitor, electrochemical double-layer electric capacitor, membrane-electrode assembly (MEA) for fuel cell or electrochromic device types.

According to a fifth object, the invention relates to a film obtained from the composition according to the invention.

Other characteristics and advantages of the invention will be better understood upon reading the description which follows and with reference to the appended drawings, given for illustrative purposes and in no way limiting.

FIG. 1 There FIG. 1 represents a thermogram of a solid electrolyte with different silica levels.

FIG. 2 There FIG. 2 represents a graph of conductivity versus temperature of a solid electrolyte with different silica levels.

FIG. 2 There FIG. 2 represents a graph of conductivity versus temperature of a solid electrolyte at different LiTFSI levels.

FIG. 2 There FIG. 2 represents a graph of the conductivity at 30 °C and the glass transition temperature (Tg) for different salt contents for a solid electrolyte (CPE for composite polymer electrolyte in English terminology).

FIG. 2 There FIG. 2 represents a plot of conductivity at 30 °C and glass transition temperature (Tg) versus silica content for a solid electrolyte with an ethylene oxide (EO) to LiTFSI molar ratio of 20:1.

FIG. 3 There FIG. 3 represents a graph of the intensity as a function of the potential of a virgin polymer (PEO) and a solid electrolyte (CPE for composite polymer electrolyte in English terminology) according to an embodiment of the invention in the presence of lithium salt PEO: Li of 20: 1 and at 30°C.

Below, we describe a summary of the invention and the associated vocabulary, before presenting the disadvantages of the prior art, and finally showing in more detail how the invention overcomes them.

In the remainder of the description, the term " solvent " means a substance, liquid or supercritical at its temperature of use, which has the property of solubilizing, diluting or extracting other substances without modifying them chemically and without itself modifying itself.

The term " polymer " means either a copolymer or a homopolymer. The term "copolymer" means a polymer comprising several different monomer units and the term "homopolymer" means a polymer comprising identical monomer units. The term "block copolymer" means a polymer comprising one or more uninterrupted sequences of each of the distinct polymer species, the polymer sequences being chemically different from each other and being linked together by a covalent bond. These polymer sequences are also called polymer blocks.

The term “ polymerization ” within the meaning of the invention designates the process of converting a monomer or a mixture of monomers into a polymer.

The term “ monomer ”, for the purposes of the invention, designates a molecule which can undergo polymerization.

The term " solid electrolyte " within the meaning of the invention may designate an electrolyte which does not flow under the effect of its own weight, preferably for a duration acceptable in the field (for example, in an order of magnitude of an hour).

The expression " consists essentially " within the meaning of the invention may mean that the composition is composed of the constituents cited in the present application, preferably is composed only of the constituents cited in the present application, namely at least one first precursor, at least one second precursor, and at least one organic polymer, optionally supplemented by one or more salts, solvents and/or inorganic particles. It may optionally comprise other components provided that the latter do not substantially modify the nature and properties of the composition.

The invention is now described in more detail and in a non-limiting manner in the following description. In the remainder of the description, the same references are used to designate the same elements.

The invention proposes to take into consideration the drawbacks of the prior art while taking into account the needs in the field of electrochemistry.

The composition within the meaning of the invention consists essentially, for example it consists, of at least one first inorganic precursor, at least one second inorganic precursor and at least one organic polymer, the at least first inorganic precursor and the at least one second inorganic precursor being dispersed in the at least one organic polymer.

ORGANIC POLYMER

The at least one organic polymer within the meaning of the invention may correspond to a polymer comprising at least one side chain, preferably at least two, more preferably at least three and even more preferably at least four. In a preferred, but non-limiting, embodiment of the invention, the at least one organic polymer may be a so-called “star” or branched or comb-like polymer.

The at least one organic polymer within the meaning of the invention may correspond to a copolymer and/or a homopolymer.

The at least one organic polymer within the meaning of the invention may be a thermoplastic polymer. A thermoplastic polymer means a polymer which is generally solid at room temperature, which may be crystalline, semi-crystalline or amorphous, and which softens upon increasing temperature, in particular after exceeding its glass transition temperature (Tg) and flowing at a higher temperature and being able to observe a clear melt upon exceeding its temperature called melting temperature (Tm) (when it is semi-crystalline), and which becomes solid again when the temperature drops below its melting point and below its glass transition temperature.

The at least one organic polymer within the meaning of the invention is preferably solid at room temperature, this avoids the risks of collapse or leakage and promotes the maintenance of the polymer network.

Advantageously, the at least one organic polymer within the meaning of the invention may be functionalized. For example, a functionalized organic polymer may comprise at least one chemical group of hydroxy, amine, halogen, alcohol, epoxy, acid and/or anhydride type to influence (i.e. improve) the electrical and/or mechanical and/or chemical properties (polymer network, formation of chemical bond, ionic conductivity) of the at least one organic polymer, preferably with the at least one first inorganic precursor and/or the at least one second inorganic precursor.

In a preferred but non-limiting embodiment of the invention, the at least one functionalized organic polymer may comprise at least one hydroxy function.

Preferably, the at least one organic polymer has a weight-average molecular mass ranging from 1000 g/mol to 500000 g/mol, preferably ranging from 10000 g/mol to 300000 g/mol, and even more preferably ranging from 15000 g/mol to 250000 g/mol. The weight-average molecular mass can be measured by size exclusion chromatography (SEC).

The at least one organic polymer within the meaning of the invention may be selected from polyoxide or copolyoxide of alkylene(s), polymethacrylate, polyacrylate, polysaccharide, polyacrylonitrile, polyimide, and/or (co)polymers of VF2 (for vinylidene fluoride), their derivative and/or their mixture.

Preferably, the at least one organic polymer within the meaning of the invention may be chosen from homopolymers and/or copolymers of ethylene oxide (e.g. POE, POE copolymer), propylene oxide, epichlorohydrin, allylglycidyl ether; halogenated polymers such as homopolymers and/or copolymers of vinyl chloride, vinylidene fluoride (PVDF for polyvinylidene fluoride in English terminology), vinylidene chloride, ethylene tetrafluoride, or chlorotrifluoroethylene, copolymers of vinylidene fluoride and hexafluoropropylene (PVDF-co-HFP); homopolymers and/or copolymers of (meth)acrylate such as poly(methylmethacrylate); homopolymers and/or copolymers of polyacrylonitrile (PAN) and/or their mixtures.

Furthermore, the at least one organic polymer is present in a mass quantity ranging from 30 to 95% in the composition, preferably in an amount ranging from 33 to 90% and even more preferably in an amount ranging from 38 to 85%.

FIRST INORGANIC PRECURSOR

The at least one first inorganic precursor is selected from the family of alkoxymetalloids of formula M-(OR1) _n , with n ranging from 1 to 4, R1 selected from hydrogen, alkyl, aryl and/or alkenyl group and M a metalloid element.

Each R1 group may independently be alkyl, cycloalkyl, aryl, aralkyl, substituted alkyl, substituted cycloalkyl, substituted aryl, substituted aralkyl, alkenyl, and/or substituted alkenyl.

An alkyl group may comprise one or more derivatives of alkanes and/or their substituents, linear and/or branched and/or cyclic, for example methyl, ethyl, propyl, butyl, phenyl, tolyl, xylyl, mesityl, naphthyl and/or their mixture.

An aryl group may comprise a functional group which is derived from an alkyl group having lost a hydrogen for example and/or their derivatives (i.e. substituted and group) and/or their mixture.

An alkenyl group may comprise one or more derivatives of an aryl group having lost a hydrogen, for example and/or their derivatives and/or their mixture, for example vinyl, ethenyl and/or ethene.

A metalloid element is defined by the classification and can correspond to an atom of Boron (B), Silicon (Si), Germanium (Ge), Arsenic (As), Antimony (Sb), Tellurium (Te) and/or Polonium (Po).

Preferably, a metalloid element is selected from silicon and/or boron and more preferably silicon.

Preferably, the at least one first inorganic precursor comprises a silyl ether, preferably silicon tetraoxyalkyl.

Another particular example may include the methylsilane group (TMS, DMS, DMPS, MDPS, DMIPS and their derivatives), the ethylsilane group (TES and its derivatives), the isopropylsilane group (TIPS and its derivatives), the TBS group (tert-butyldimethylsilane and its derivatives), the tert-butyldiphenylsilane group and its derivatives (TBDPS), the phenylsilane group and its derivatives, the trialkylsilane group and its derivatives, the propylsilane group and its derivatives and/or the hexylsilane group and its derivatives.

For example, the at least one first inorganic precursor may be selected from methyltrimethoxysilane (CH ₃ Si(OCH ₃ ) ₃ ), methyltriethoxysilane (CH ₃ Si(OC ₂ H ₅ ) ₃ ), ethyltrimethoxysilane (C ₂ H ₅ Si(OCH ₃ ) ₃ ), ethyltriethoxysilane (C ₂ H ₅ Si(OC ₂ H ₅ ) ₃ ), propyltrimethoxysilane (C ₃ H ₇ Si(OCH ₃ ) ₃ ), propyltriethoxysilane (C ₃ H ₈ Si(OC ₂ H ₅ ) ₃ ), isobutyltrimethoxysilane (iC ₄ H ₉ Si(OCH ₃ ) ₃ ), pentyltriethoxysilane (C ₆ H ₅ Si(OC ₂ H ₅ ) ₃ ), octyltriethoxysilane (C ₈ H ₁₇ Si(OC ₂ H ₅ ) ₃ ), octadecyltrimethoxysilane (C ₁₈ H ₃₇ Si(OCH ₃ ) ₃ ), octadecyltriethoxysilane (C ₁₈ H ₃₇ Si(OC ₂ H ₅ ) ₃ ), phenyltrimethoxysilane (C ₆ H ₅ Si(OCH ₃ ) ₃ ), tetramethoxysilane (Si(OCH ₃ ) ₄ ), tetraethoxysilane (Si(OC ₂ H ₅ ) ₄ ), tetrapropoxysilane (Si(OnC ₃ H ₇ ) ₄ ), tetraisopropoxysilane (Si(OiC ₃ H ₇ ) ₄ ), tetrabutoxysilane Si(OnC ₄ H ₉ ) ₄ ), tetrakis(s-butoxy)silane (Si(O-sec-C ₄ H ₉ ) ₄ ), tetrakis(2-ethyl-butoxy)silane (Si(OCH ₂ CH(C ₂ H ₅ ) ₂ ) ₄ ), tetrakis(2-ethyl-hexoxy)silane (Si(OCH ₂ CH(C ₂ H ₅ )(C ₄ H ₉ ))) ₄ ), etrakis(2-methoxy-ethoxy)silane (Si(OCH ₂ CH ₂ OCH ₃ ) ₄ ), tetraphenoxysilane (Si(OC ₆ H ₅ ) ₄ , tetracetoxysilane (Si(OOCCH ₃ ) ₄ ), methyltriacetoxysilane (CH ₃ Si(OOCCH ₃ ) ₃ , ethyltriacetoxysilane (C ₂ H ₅ Si(OOCCH ₃ ) ₃ ), di-t-butoxydiacetoxysilane ((tC ₄ H ₉ O)Si(OOCCH ₃ ) ₂ ), triethoxysilane (C ₆ H ₁₆ O ₃ Si), dimethylethoxysilane (C ₄ H ₁₂ OSi), methyldiethoxysilane (C ₆ H ₁₆ O ₂ Si), diphenyldiethoxysilane (C ₁₆ H ₂₀ O ₂ Si), n-octyltriethoxysilane (C ₁₄ H ₃₂ O ₃ Si), phenyltrimethoxysilane (C ₉ H ₁₄ O ₃ Si), their mixtures, and/or their derivatives (i.e. substituted and group).

For example, the at least one first inorganic precursor may be selected from: Tetramethoxysilane (TMOS), Tetraethoxysilane (TEOS), Propyltriethoxysilane (C ₉ H ₂₂ O ₃ Si), diphenyldiethoxysilane (C ₁₆ H ₂₀ O ₂ Si) ethyltriethoxysilane (C ₈ H ₂₀ O ₃ Si), methyltriethoxysilane (C ₇ H ₁₈ O ₃ Si), n-octyltriethoxysilane (C ₁₄ H ₃₂ O ₃ Si), phenyltriethoxysilane (C ₁₂ H ₂₀ O ₃ Si), and/or phenyl trimethoxysilane (C ₉ H ₁₄ O ₃ Si).

Furthermore, the at least one first inorganic precursor may be present in a mass quantity ranging from 0.5 to 30% in the composition, preferably in an amount ranging from 1 to 20% and preferably in an amount ranging from 1 to 15% and even more preferably in an amount ranging from 1 to 5%.

At least one first inorganic precursor allows the creation of chemical bonds with the at least one organic polymer and/or with the at least one second inorganic precursor. The at least one first inorganic precursor allows reaction (hydrolysis and/or condensation) with the at least one second inorganic precursor and preferably with at least one hydrolyzable and/or hydrolyzed group of said at least one second inorganic precursor.

This also helps to contribute to the dispersion of the first inorganic precursor in the at least one organic polymer.

Advantageously, the at least one first inorganic precursor makes it possible to provide a metalloid and particularly preferably Si, particularly preferred in electrochemistry.

Furthermore, the at least one first inorganic precursor makes it possible to provide activatable and/or reactive chemical functions in the composition.

In addition, the presence of an inorganic precursor helps to participate in and improve the mechanical properties.

SECOND INORGANIC PRECURSOR

The at least one second inorganic precursor is selected from (R2-O) _{4- m} -M-(R3) _m with m ranging from 1 to 3, R2 selected from hydrogen, alkyl, aryl and/or alkenyl group, R3 selected from alkyl, aryl and/or alkenyl group comprising a hydrolyzable function and M a metalloid element.

Each R2 group may independently be alkyl, cycloalkyl, aryl, aralkyl, substituted alkyl, substituted cycloalkyl, substituted aryl, substituted aralkyl, alkenyl, and/or substituted alkenyl.

An alkyl group may comprise one or more derivatives of alkanes and/or their substituents, linear and/or branched and/or cyclic, for example methyl, ethyl, propyl, butyl, tert-butyl, phenyl, tolyl, xylyl, mesityl, naphthyl, etc. and/or their mixture.

An aryl group may comprise a functional group which is derived from an alkyl group having lost a hydrogen for example and/or their derivatives (i.e. substituted) and/or their mixture.

An alkenyl group may comprise one or more derivatives of an aryl group having lost a hydrogen, for example and/or their derivatives and/or their mixture, for example vinyl, ethenyl, ethene.

The R3 group comprises a hydrolyzable group and preferably comprises a hydrolyzable function. A hydrolyzable function may be selected from acyloxy and anhydride. Preferably, the R3 group comprises an anhydride function and more preferably a succinic anhydride function.

Preferably, the R3 group may also comprise a succinic alkyl group.

For example, the at least one second inorganic precursor may be selected from TESPSA for 3-(triethoxysilyl)propylsuccinic anhydride, (2-cyanoethyl)triethoxysilane and/or any other inorganic precursor preferably comprising a hydrolyzable function and a succinic alkyl group.

A metalloid element is defined by the classification and can correspond to an atom of Boron (B), Silicon (Si), Germanium (Ge), Arsenic (As), Antimony (Sb), Tellurium (Te) and/or Polonium (Po).

Preferably, a metalloid element is selected from silicon and/or boron and more preferably silicon.

Furthermore, the at least one second inorganic precursor may be present in a mass quantity ranging from 0.5 to 30% in the composition, preferably in a mass quantity ranging from 1 to 20% and preferably in an amount ranging from 1% to 15% and even more preferably in an amount ranging from 1 to 10%.

Furthermore, the molar ratio between the at least one first inorganic precursor and the at least one second inorganic precursor may be between 0.1 and 10 in the composition, preferably between 0.1 and 5 and preferably between 0.1 and 1 and even more preferably between 0.1 and 0.5.

The at least one second inorganic precursor is the catalyst for the reaction.

Indeed, the hydrolyzable function and preferably the succinic anhydride function hydrolyzes to generate two groups, preferably carboxylic acids, which will activate the sol-gel reaction and produce esterification reactions. These interactions will lead to a solid electrolyte with improved properties.

OTHERS

The composition according to the invention may also comprise, preferably consist of other components.

In one embodiment, the composition may further comprise at least one salt. A salt may correspond within the meaning of the classification to a metal such as an alkali, alkaline earth, transition and/or other metal. Preferably, the composition may further comprise one or more lithium, sodium, and/or potassium salts. More preferably, at least one salt may comprise at least one alkali metal and more preferably a lithium. One or more lithium salts may be chosen from: Lithium bis-(oxalato)borate (LiBOB or LiB(C ₂ O ₄ ) ₂ )); Lithium hexafluorophosphate (LiPF ₆ ); lithium fluorate (LiFO ₃ ); lithium metaborate (LiBO ₂ ), Lithium perchlorate (LiClO ₄ ); lithium nitrate (LiNO ₃ ); Lithium hexafluoroarsenate (LiAsF ₆ ); Lithium tetrafluoroborate (LiBF ₄ ); Lithium 4,5-dicyano-2-(trifluoromethyl)imidazol-l-ide (LiTDI); Lithium bis(fluorosulfonyl)imide (LiFSI); lithium trifluoromethanesulfonate (LiTF), Lithium bis-trifluoromethanesulfonimide (LiTFSI); LithiumN-fluorosulfonyltrifluoro-methansulfonylamide (Li-FTFSI); Lithium tris(fluorosulfonyl)methide (Li-FSM); Lithium bis(perfluoroethylsulfonyl)imide (LiBETI); Lithium difluoro(oxalate)borate (LiDFOB); Lithium 3-polysulfide sulfolane (LiDMDO), lithium trifluoroacetate (CF ₃ COOLi), dilithium dodecafluorododecaborate (Li ₂ B ₁₂ F ₁₂ ), lithium bis(oxalate)borate (LiBC ₄ O ₈ ), lithium mineral polysulfides (S _y Li with y greater than or equal to 2), their derivatives and/or their mixtures.

The composition may further comprise at least one salt in a mass quantity ranging from 1 to 50% of the total weight of the composition, preferably in an amount ranging from 1 to 40% and even more preferably in an amount ranging from 1 to 25%.

Advantageously, the at least one organic polymer makes it possible to promote the dissociation of the salt and the transport of ions.

The composition may also further comprise inorganic particles.

The inorganic particles preferably have a particle size of less than 50 µm. This particle size can be measured using known techniques, for example by laser particle size measurement.

Inorganic particles within the meaning of the invention may comprise ceramics, preferably conductive ceramics.

Thus in embodiments, the composition may consist essentially, preferably consist of at least one first inorganic precursor, at least one second inorganic precursor and at least one organic polymer and/or at least one ionic salt, and/or at least inorganic particles and/or at least one solvent.

In a particular embodiment of the invention, the composition may consist essentially, preferably consist, of at least one first inorganic precursor, at least one second inorganic precursor, at least one organic polymer, and at least inorganic particles.

In a particular embodiment of the invention, the composition may consist essentially, preferably consist of at least one first inorganic precursor, at least one second inorganic precursor, at least one organic polymer, and at least one salt.

In a particular embodiment of the invention, the composition may consist essentially, preferably consist, of at least one first inorganic precursor, at least one second inorganic precursor, at least one organic polymer, at least one ionic salt and inorganic particles.

In a particular embodiment of the invention, the composition may consist essentially, preferably consist, of at least one first inorganic precursor, at least one second inorganic precursor, at least one organic polymer, and at least one solvent.

In a particular embodiment of the invention, the composition may consist essentially, preferably consist, of at least one first inorganic precursor, at least one second inorganic precursor, at least one organic polymer, at least one solvent and at least one ionic salt.

In a particular embodiment of the invention, the composition may consist essentially, preferably consist, of at least one first inorganic precursor, at least one second inorganic precursor, at least one organic polymer, at least one solvent and at least inorganic particles.

In a particular embodiment of the invention, the composition may consist essentially, preferably consist, of at least one first inorganic precursor, at least one second inorganic precursor, at least one organic polymer, at least one solvent, at least one ionic salt, and at least inorganic particles.

The composition does not comprise an additional acid and/or base catalyst and/or acid and/or base chelator because the second inorganic precursor acts as such.

Such a composition according to the invention allows the combination and preferably the dispersion of inorganic precursors within at least one organic polymer. The composition allows the intimate mixing of inorganic precursors with at least one organic polymer. The composition allows different applications and in particular applications in electrochemistry. In addition, such a composition allows the stabilization of the components and in particular the ionic components within the at least one organic polymer.

USE

The composition may be used for a solid electrolyte, preferably for forming a solid electrolyte. The composition may be for forming a solid electrolyte, preferably for forming a solid electrolyte.

Thus the invention relates to the use of the composition to form preferably to specifically form a solid electrolyte. The use of the composition for solid electrolyte allows control of chemical reactions and in particular of the initiation of sol-gel reactions. In addition, thanks to the use of such a composition without catalyst, there is no reaction residue present and the solid electrolyte will have better electrochemical stability.

Furthermore, the composition may be used in film form, preferably to form a film, preferably to specifically form a film according to techniques known to those skilled in the art. Thus, the invention also relates to a film obtained from the electrochemical composition and preferably a solid polymer film. For example, the composition may be deposited on a support so that after polymerization it forms said film.

E ELECTROLY T E SOLID

According to another aspect, the invention relates to a solid electrolyte. A solid electrolyte is capable of being obtained from the composition according to the invention. Preferably, the invention relates to a solid electrolyte obtained from the composition according to the invention.

A solid electrolyte may be a separator, a component of a separator, a component of a catholyte, a component of an anolyte, a component of an accumulator, a battery, a capacitor, an electrochemical double-layer electric capacitor, a membrane-electrode assembly (MEA) for a fuel cell, or an electrochromic device.

Thus, the invention also relates to the use of a solid electrolyte according to the invention, in electrochemical devices of the accumulator, battery, capacitor, electrochemical double-layer electric capacitor, membrane-electrode assembly (MEA) type for fuel cell or electrochromic device.

A solid electrolyte may comprise an inorganic polymer mixed in at least one organic polymer.

ORGANIC POLYMER

An organic polymer may correspond to a polymer within the meaning of the invention as disclosed above.

INORGANIC POLYMER

An inorganic polymer may correspond to the condensation of at least one first inorganic precursor, preferably according to the invention, with at least one second inorganic precursor, preferably according to the invention.

Indeed, as a result of hydrolysis and polycondensation reactions of inorganic alkoxides, a three-dimensional oxide network is formed. For example, the presence of the first inorganic precursor and the second inorganic precursor leads to the formation of ester bonds between the hydroxyl groups attached either to the organic polymer or to the silanols and the carboxyl groups of the second hydrolyzed inorganic precursor, leading to the formation of a hybrid network.

One of the main advantages of such an inorganic polymer is its perfect compatibility with a wide variety of alkoxide precursors, as well as the solubility of its precursors in common organic solvents (alcohol, THF, etc.).

The presence of the at least one second inorganic precursor allows the hydrolysis of groups preferably succinic groups, the at least one first precursor then allows the reaction (hydrolysis and condensation) with the hydrolyzed groups of the at least one second inorganic precursor preferably carboxylic groups from the at least one second hydrolyzed inorganic precursor. The reaction leads to the formation of ester bonds between the hydroxyl groups attached either to the PEO-based polymer or from silanols and the carboxyl groups of the at least one second hydrolyzed inorganic precursor, leading to the formation of an organic/inorganic hybrid network. This reaction improves the strength performance and mechanical properties of the final electrolyte. In addition, the composition does not require additional acid or base catalysts to activate the sol-gel reaction. This is an advantage in terms of electrolyte purification because only ethanol and water are formed and easily removed.

Thus, the at least one organic polymer comprises a condensation of the at least one first inorganic precursor with the at least one second inorganic precursor in its hydrolyzed form to form an inorganic network. Said inorganic network (i.e. inorganic polymer) condenses with water minus an organic polymer to form an organic/inorganic hybrid network. Furthermore, the mass ratio between the inorganic polymer and the organic polymer may correspond to a value ranging from 0.01 to 0.5, preferably ranging from 0.05 to 0.25.

The presence of an inorganic polymer makes it possible to replace the addition of acid and/or base necessary to initiate sol-gel reactions.

In addition, this new route from inorganic precursor allows the generation of acid groups of the carboxylic acid type for example which make it possible to activate the sol-gel reaction from inorganic precursor and preferably hydrolysis of inorganic precursor.

The synthesis of the solid electrolyte in the presence of at least one organic polymer by precursor hydrolysis acts as a catalyst and co-precursors leads to a fully amorphous composite with a hybrid silica network.

Additionally, the presence of an inorganic fraction improves the electrochemical stability voltage window.

The solid electrolyte may have an ionic conductivity of at least 10 ^-5 S/cm at 25°C, obtained by electrochemical impedance spectroscopy. Preferably, the solid electrolyte may have, in the presence of lithium salts, an ionic conductivity of at least 10 ^-4 S/cm at 25°C, more preferably of at least 0.5.10 ^-4 S/cm at 25°C.

Advantageously, the solid electrolyte has good homogeneity of the structure of the electrolyte, preferably on the submicron scale, and good purity (absence of catalyst and residues).

The solid electrolyte also exhibits good mechanical properties and ionic conductivity. The gel obtained from the sol-gel reaction exhibits good condensation, close to 100%. Indeed, it is not liquid while being able to be handled and stretched without breaking or collapsing.

A solid electrolyte according to the invention has an improved lifespan. A solid electrolyte also has good mechanical and electrical properties. In addition, the solid electrolyte according to the invention also has good stability due to the absence of reaction products from acidic or basic catalysts. In addition, the solid electrolyte according to the invention does not contain any species that are toxic, corrosive, or that increase its dissolution.

According to another aspect, the invention relates to a method of manufacturing a solid electrolyte comprising an organic and inorganic hybrid network. Preferably, it is a method of manufacturing a solid electrolyte according to the invention.

A manufacturing method according to the invention may comprise a step of preparing a composition, preferably in solution in a solvent, comprising at least one organic polymer comprising at least one side chain and at least one first inorganic precursor selected from the family of alkoxymetalloids of formula M-(OR1) _n with n ranging from 1 to 4 and R1 selected from hydrogen, alkyl, aryl, and/or alkenyl group, and M a metalloid element.

A solvent can correspond to a usual solvent for sol-gel reactions.

For example, a solvent might be THF, acetone, and/or DMF.

The step of preparing a composition may comprise adding at least one salt and preferably at least one lithium salt to the composition and more preferably as disclosed above.

The step of preparing a composition may comprise adding inorganic particles, preferably inorganic particles as also disclosed above.

During the step of preparing the composition, the mass ratio between the at least one first inorganic precursor and the at least one organic polymer may be greater than or equal to 0.01, preferably greater than or equal to 0.02.

During the step of preparing the composition, the mass ratio between the at least one first inorganic precursor and the at least one organic polymer may be less than or equal to 0.50, preferably less than or equal to 0.15.

The step of preparing a composition does not include an acid and/or basic catalyst.

The preparation step can be carried out using equipment (i.e. scales, mixer, etc.) and glassware commonly used in the field.

The method for manufacturing a solid electrolyte may comprise a step of adding at least one second inorganic precursor selected from (R2-O)4-mM-(R3) _m with m ranging from 1 to 3, R2 selected from hydrogen, alkyl, aryl and/or alkenyl group, R3 selected from alkyl, aryl and/or alkenyl group comprising a hydrolyzable function and M a metalloid element. Preferably at least one second inorganic precursor as disclosed above.

The addition step can be carried out using a pipette and other equipment allowing for addition preferably drop by drop.

During the step of adding the at least one second inorganic precursor, the mass ratio between the at least one second inorganic precursor and the at least one organic polymer may be greater than or equal to 0.010, preferably greater than or equal to 0.050.

During the step of adding the at least one second inorganic precursor, the mass ratio between the at least one second inorganic precursor and the at least one organic polymer may be less than or equal to 0.50, preferably less than or equal to 0.40.

During the step of adding the at least one second inorganic precursor, the molar ratio between the at least one first inorganic precursor and the at least one second inorganic precursor may be greater than or equal to 0.1.

During the step of adding the at least one second inorganic precursor, the molar ratio between the at least one first inorganic precursor and the at least one second inorganic precursor may be less than or equal to 10, preferably less than or equal to 5 and more preferably less than or equal to 1.

The manufacturing process may comprise a step of forming a preparation by hydrolysis and condensation of the composition so as to form an inorganic network. The hydrolysis step may be initiated using the precursors. Indeed, the addition of two inorganic precursors according to the invention makes it possible to initiate the sol-gel reaction. In particular, the second inorganic precursor acts as a reaction catalyst once hydrolyzed to initiate this reaction. The reaction products (water/alcohol) can be easily removed. For example, the process may comprise a drying and/or evaporation step to remove said products. Drying may, for example, correspond to vacuum drying. The reaction leads to the formation of an inorganic network within the polymer matrix. Thus, the process according to the invention does not comprise catalysis. Furthermore, during the formation of the inorganic network within the matrix, some of the alkali or alkaline-earth elements remain trapped in the inorganic network within the polymer matrix, which makes it possible to enrich the inorganic network within the polymer matrix with alkali or alkaline-earth elements.

The method may include a step of forming a solid electrolyte from the preparation. The forming step may include dip-coating, spin-coating, roll coating, doctor blade, electrospraying, or electrophoresis.

The manufacturing process according to the invention makes it possible to dispense with the step of adding an acid and/or basic catalyst and/or an acid and/or basic chelator other than the second inorganic precursor. Thus, the process according to the invention makes it possible to facilitate the manufacture of a solid electrolyte.

Furthermore, the method according to the invention makes it possible to broaden the choice of media and solvents.

A particular example of the invention is illustrated below. This example illustrates a preferred route but does not limit the invention to this particular example.

EXPERIENCE

Material

The experiments were carried out with a 4-pointed star-shaped poly(ethylene oxide)-stat-poly(propylene oxide) (PEO ₁₇₀ -stat-PPO ₃₀ ) with a molar mass of 9500 g/mol. Anhydrous tetrahydrofuran (THF, ≥99.9%, inhibitor-free), tetraethyl orthosilicate (TEOS, 98%) were also used, as well as lithium bis(trifluoromethanesulfonyl)imide (LiTFSI, 99%) and 3-(triethoxysilyl)propylsuccinic anhydride (TESPSA, 95%).

Synthesis

The star-type PEO -stat -PPO (hereinafter PEO) was mixed with LiTFSI and solubilized with THF at various ethoxide/lithium molar ratios (20:1, 13:1, 10:1, 8:1 and 6:1) in a 20 ml vial at 30% grams per 100 ml. Before the addition of TEOS, the appropriate amount of TESPSA was added dropwise to the mixture using a micropipette. The mixture was stirred with a magnetic stirrer for 30 minutes allowing the hydrolysis of the succinic anhydride functions, then TEOS was added at a TESPSA/TEOS molar ratio of 2:1. The final preparation was stirred for 6 h at 60°C before being cast on stainless steel and dried under vacuum at 80°C for 24 hours.

Solid electrolytes were prepared via a non-hydrolytic sol-gel reaction using both TEOS and TESPSA precursors. All components are preferentially miscible in THF, leading to a homogeneous solution before the sol-gel reaction.

The synthesis of the preparation was carried out in three steps: solubilization of the polymer and the lithium salt in THF, followed by the addition of TESPSA allowing the hydrolysis of the succinic groups, then TEOS, was added to initiate the hydrolysis and condensation with the carboxylic acids resulting from the hydrolysis of TESPSA. The reaction leads to the formation of ester bonds between the hydroxyl group attached to either the PEO polymer or the silanols and the carboxyl groups of the hydrolyzed TESPSA, leading to the formation of a hybrid network. This reaction improves the strength performance and mechanical properties of the final electrolyte. No additional acid or alkaline catalyst to activate the sol-gel reaction was used. This is an advantage in terms of electrolyte purification since only ethanol and water are formed and can be removed during drying for example.

The thermal stability of CPE (composite polymer electrolyte) was studied by thermogravimetric analysis (TGA). FIG. 1 shows thermograms of CPEs with different theoretical silica amounts: 15 wt% (curve A), 10 wt% (curve B), and 5 wt% (curve C). Since the mass loss of the virgin polymer (curve D) is 100% and the percentage of residues at 580 °C is 0%, the solid residues of the CPE samples represent the amount of inorganic phase present in the material. Interestingly, the percentage of solid residues for each sample is in agreement with the theoretical amounts of silica in the initial samples, i.e., 7 wt%, 10 wt%, and 12 wt%, respectively. For all thermograms, degradation starts above 340 °C, indicating that CPEs are stable up to 340 °C even with the lowest amount of silica (5 wt%). Furthermore, thermograms reveal that the decomposition of CPEs occurred at a temperature 20°C higher than that of the virgin polymer (320°C), indicating an improvement in thermal stability with the addition of silica.

The impact of silica quantity and salt content on the glass transition temperature was studied by DSC (Differential Scanning Calorimetry), as shown in Figure 2. DSC was performed under N2 atmosphere. For each sample, the temperature was increased from 40 to 240 °C and then cooled to -65 °C at a rate of 10 °C/min. To evaluate the potential of CPE for applications in electrochemistry, particularly batteries, the ionic conductivity, electrochemical stability and the influence of silica and lithium salt concentrations were studied and reported in Figure 2. FIG. 2 illustrates the conductivity as a function of temperature for different amounts of silica. The corresponding Arrhenius diagram is shown for a temperature ranging from 10 °C to 90 °C. These results show that the ionic conductivity decreases with the amount of silica, the highest conductivity values are obtained for the sample with the lowest amount of silica, i.e. 5% by weight, with a value around 10-4 S.cm-1 at 30° C. The conductivity of the in situ solid electrolyte has no significant change during the cooling cycles on the conductivity measurement between 10 °C and 90 °C.

There FIG. 2 illustrates the ionic conductivity as a function of temperature for different salt contents for CPE_10%. The corresponding Arrhenius diagram is shown for a temperature between 10 °C and 90 °C. The conductivity values decrease with salt content for lower temperatures, from 10 °C to 40 °C with a maximum conductivity at a molar ratio of ethylene oxide (EO) to LiTFSI of 20:1. This conductivity trend is consistent with Tg (glass transition temperature). Indeed, for lower Tg values (< -50 °C), the mobility of the polymer chain is high and the lithium salt is better solubilized and transported, resulting in higher conductivity values (6.4.10 ^-5 S/cm). Note that the conductivity values in this case were obtained from CPE with 10 wt% fillers, and are lower than the best values obtained with CPE containing 5 wt% fillers as shown in FIG. 2 (up to 10 ^-4 at 30°C).

There FIG. 2 illustrates both the conductivity at 30 °C and the glass transition temperature versus the salt content (EO/LITFSI molar ratio), highlighting a correlation. Inverse trends with respect to salt content are observed. Tg increases significantly between -45 °C and -30 °C (for EO/LITFSI molar ratios of 10 to 20), inducing a decrease in conductivity. The Tg plateau at -30 °C (for EO/LITFSI molar ratios of 6 to 10) induces a limited decrease in conductivity. This conductivity trend is consistent with the Tg trend. Indeed, for lower Tg values (below -50 °C), the polymer chain mobility is high and the lithium salt is better solubilized and transported, leading to higher conductivity values (6.4.10 ^-5 s/cm). The conductivity values in this case were obtained from CPE with 10 wt% fillers, and are lower than the best values obtained with CPE containing 5 wt% fillers as shown in FIG. 2 (up to 10 ^-4 at 30°C).

There FIG. 2 illustrates the conductivity at 30 °C and the glass transition temperature (Tg) as a function of silica content (for the EO/LITFSI molar ratio 20:1). Inverse trends with respect to silica content are also observed. These results show that the ionic conductivity decreases with the amount of silica. The highest conductivity values are obtained for the sample with the lowest amount of silica, i.e., 5 wt%, with a value of approximately 10 ^-4 s.cm ^-1 at 30 °C. The Tg increases up to 7 °C, from 5 wt% to 20 wt% silica (from -56 to -43 °C), inducing a decrease in conductivity from 1.10 ^-4 s/cm to 2.10 ^-5 s/cm. Thus, the addition of silica reduces the ionic conductivity since the amount of non-conducting fraction is increased.

There FIG. 3 illustrates the current-potential curves of the virgin polymer PEO and CPE_10%. The electrochemical stability window of the in situ synthesized CPE (CPE_10%) and virgin polymer (PEO) was determined via LSV (Linear Sweep Voltammetry) from 2.8 V to 6 V at 1 mVs ^-1 . Stainless steel and metallic lithium serve as working and reference electrodes. A low current was observed up to 4 V compared to Li/Li ⁺ for the silica-free solid electrolyte (virgin polymer), which represents the oxidation and decomposition process of PEO. CPE exhibits an improved electrochemical stability window of up to 5.3 V compared to Li/Li ⁺ . Li/Li ⁺ , which is superior to previously reported high-voltage solid polymer electrolytes obtained by in situ sol-gel reaction .

CONCLUSION

Thus, the present invention allows a new route for synthesizing a solid electrolyte from a composition without acid and/or basic catalyst but comprising, essentially consisting of two inorganic precursors and an organic polymer. An inorganic precursor preferably a reactive alkoxide and a lithium alcoholate and/or a lithium alkoxy alcoholate, preferably 3-(Trithoxysilyl)propylsuccinic anhydride (TESPSA), and tetraethyl orthosilicate (TEOS) to generate an in situ sol-gel reaction within a polymer matrix preferably of the PEO type leading to a composite polymer electrolyte (CPE) displaying an improved ionic conductivity around 10 ^-4 S.cm ^-1 at 30°C.

The synthesis of solid electrolyte by hydrolysis of inorganic precursor preferably reactive alkoxide and lithium alcoholate and/or lithium alkoxy alcoholate preferably TEOS in the presence of TESPSA as catalyst leads to a solid electrolyte with an organic polymer comprising at least one side chain preferably of the totally amorphous PEO type with a silica network observable by microscopy techniques (scanning electron microscopy and atomic force microscopy). The characterization of the inorganic phase by differential scanning calorimetry (DSC) shows that the inorganic network contributes to reduce the crystallinity of the organic polymer preferably PEO, leading to an amorphous structure with high conductivity. In addition, the presence of an inorganic fraction improves the electrochemical stability window up to 5.3 V compared to Li/Li ⁺ .

The invention may be the subject of numerous variations and applications other than those described above. In particular, unless otherwise indicated, the different structural and functional characteristics of each of the implementations described above should not be considered as combined and/or closely and/or inextricably linked to each other, but on the contrary as simple juxtapositions. Furthermore, the structural and/or functional characteristics of the different embodiments described above may be the subject in whole or in part of any different juxtaposition or any different combination.

Claims (12)

Composition consisting essentially of at least one first inorganic precursor, at least one second inorganic precursor, said inorganic precursors being dispersed in at least one organic polymer, and of which

• The at least one first inorganic precursor is selected from the family of alkoxymetalloids of formula M-(OR ₁ ) _n with n ranging from 1 to 4 and R ₁ selected from hydrogen, alkyl, aryl, and/or alkenyl group, and M a metalloid element,
• The at least one second inorganic precursor is selected from (R ₂ -O) _4-m -M-(R ₃ ) _m with m ranging from 1 to 3, R ₂ selected from hydrogen, alkyl, aryl and/or alkenyl group, R ₃ selected from alkyl, aryl and/or alkenyl group and comprising a hydrolyzable function and M a metalloid element, and
• The at least one organic polymer comprises at least one side chain.

Composition according to claim 1, characterized in that the at least one organic polymer is a star polymer. Composition according to claim 1 or 2, characterized in that the at least one organic polymer is selected from polyoxide or copolyoxide of alkylene(s), polymethacrylate, polyacrylate, polysaccharide, polyacrylonitrile, polyimide and/or (co)polymers of VF2 (for vinyldiene fluoride), their derivative and/or their mixture. Composition according to one of the preceding claims, characterized in that the at least one second inorganic precursor is selected from TESPSA, an inorganic precursor comprising a hydrolyzable function and a succinic alkyl group. Composition according to one of the preceding claims, characterized in that the metalloid element is selected from Si and/or B. Composition according to one of the preceding claims, characterized in that it further comprises at least one salt, preferably one or more lithium salts. Composition according to one of the preceding claims, characterized in that it also comprises inorganic particles. Use of the composition according to one of the preceding claims to form a solid electrolyte. Solid electrolyte, characterized in that it comprises at least one inorganic network dispersed in at least one organic polymer, said inorganic network corresponding to a condensation between at least one first inorganic precursor and at least one second inorganic precursor,

• The at least one first inorganic precursor is selected from the family of alkoxymetalloids of formula M-(OR ₁ ) _n with n ranging from 1 to 4 and R ₁ selected from hydrogen, alkyl, aryl, and/or alkenyl group, and M a metalloid element,
• The at least one second inorganic precursor is selected from (R ₂ -O) _4-m -M-(R ₃ ) _m with m ranging from 1 to 3, R ₂ selected from hydrogen, alkyl, aryl and/or alkenyl group, R ₃ selected from alkyl, aryl and/or alkenyl group and comprising a hydrolyzable function and M a metalloid element, and
• The at least one organic polymer comprises at least one side chain.

Solid electrolyte according to claim 9, characterized in that the at least one organic polymer comprises a condensation of the at least one first inorganic precursor with the at least one second inorganic precursor in its hydrolyzed form to form an inorganic network, said inorganic network condensing with the at least one organic polymer to form an organic/inorganic hybrid network. Film obtained from the composition according to any one of claims 1 to 7. Use of a solid electrolyte according to one of claims 9 or 10 in electrochemical devices of the accumulator, battery, capacitor, electrochemical double-layer electric capacitor, membrane-electrode assembly (MEA) type for fuel cell or electrochromic device.