Process for preparing a polymer and solid polymer electrolyte incorporating such a polymer

Abstract

The present invention relates to a process for manufacturing a polymer comprising the following steps: i) bringing into contact: a) at least one styrenic monomer comprising at least one polyether; and b) a free radical initiator; ii) heating the mixture to a temperature ranging from 40 to 110°C, preferably from 60 to 90°C, more preferably from 75 to 85°C.

Description

Title of the invention: Process for preparing a polymer and solid polymer electrolyte incorporating such a polymer. Technical field

[0001] The present invention relates to the field of polymers and solid electrolytes incorporating a polymer.

[0002] More particularly, the present invention relates to a method for manufacturing a polymer, a polymer obtainable by said manufacturing method, and a solid polymer electrolyte comprising such a polymer and at least one electrolyte salt. The invention also relates to a method for manufacturing said solid polymer electrolyte, an all-solid-state battery cell comprising said solid polymer electrolyte, and an all-solid-state battery comprising said cell. Previous techniques

[0003] A polymer is obtained by assembling a plurality of monomer motifs repeating throughout the polymer chain.

[0004] Certain large molecules, called "macromomomers", have a terminal group enabling them to form a monomer motif and incorporate into a polymer chain.

[0005] PEGylated styrene, a styrenic molecule comprising a poly(ethylene oxide) (PEG) group, is an example of a well-known macromonomer, particularly for applications in the field of biology.

[0006] Generally, it is difficult to polymerize macromonomers, given their large size which disrupts the propagation of polymerization.

[0007] Classically, in order to polymerize macromonomers, reversible polymerization methods, known as controlled or living polymerization methods, such as atom transfer radical polymerization (ATRP), reversible addition-fragmentation chain transfer controlled radical polymerization (RAFT) or nitroxide polymerization (NMP), are preferred to methods such as free-radical polymerization (FRP).

[0008] Indeed, controlled polymerization methods have several advantages including the accuracy of the molecular weight of the resulting polymer, and the ability to copolymerize in block.

[0009] However, they generally require high temperatures, a transition metal-based catalyst or an exotic radical initiator, inert gas conditions, and long reaction times.

[0010] Furthermore, the accessibility of the polymer during polymerization remains limited and, by Consequently, the conversion rate of the final polymer is also higher.

[0011] There is therefore a need to develop a new polymerization process, in particular for the manufacture of polymer obtained from a macromonomer motif, making it possible to overcome the above disadvantages. Description of the invention

[0012] The invention therefore relates to a process for manufacturing a polymer comprising the following steps:

[0013] i) bring into contact:

[0014] a) at least one styrenic monomer comprising at least one polyether; and

[0015] b) a free radical initiator;

[0016] ii) heat the mixture to a temperature ranging from 40 to 110°C, preferably ranging from 60 to 90°C, more preferably ranging from 75 to 85°C.

[0017] Surprisingly, it has been found that the process for manufacturing a polymer according to the invention based on free radical polymerization is particularly advantageous for polymers obtained from macromonomers and allows polymerization without requiring a transition metal-based catalyst or an exotic radical initiator, nor inert gas conditions, at low temperature, and leading to an improved conversion rate.

[0018] Furthermore, the process for manufacturing a polymer according to the invention is carried out without solvent, so that mass production can be easily achieved.

[0019] Furthermore, the process for manufacturing a polymer according to the invention makes it possible to obtain a polymer insoluble in many common solvents (water, DMSO, DCM, DMF, anisole, NMP, ethyl acetate, ethanol, THF etc.), which is particularly advantageous for applications in diverse fields such as the field of solid polymer electrolytes for all-solid batteries, but also in a membrane of a gas separation device, a membrane of a carbon storage device, or even a membrane of a drug delivery device.

[0020] The invention also relates to a method for manufacturing a solid polymer electrolyte comprising the following steps:

[0021] i) bring into contact:

[0022] a) at least one styrenic monomer comprising at least one polyether; and

[0023] b) a free radical initiator;

[0024] ii) heat the mixture to a temperature ranging from 40 to 110°C, preferably ranging from 60 to 90°C, more preferably ranging from 75 to 85°C;

[0025] iii) recover the polymer obtained;

[0026] at least one electrolyte salt being added during step i) and / or step iii).

[0027] The invention also relates to a polymer that can be obtained by a manufacturing process according to the invention, as well as a solid polymer electrolyte comprising at least one electrolyte salt and a polymer according to the invention.

[0028] Other objects of the invention are an all-solid battery cell comprising the solid polymer electrolyte according to the invention, and an all-solid battery comprising the cell according to the invention.

[0029] Other features, aspects, objects and advantages will become apparent from the description that follows and from the following examples, given purely for illustrative purposes.

[0030] It is specified that the expression "from... to..." used in this description of the invention should be understood as including each of the limits mentioned.

[0031] In this description, the expression "at least one" used should be considered equivalent to the expression "one or more".

[0032] As indicated above, the process for manufacturing the polymer according to the invention comprises a step i) of contacting:

[0033] a) of at least one styrenic monomer comprising at least one polyether; and

[0034] b) a free radical initiator.

[0035] In a step ii), the mixture comprising a) and b) obtained is then heated to a temperature ranging from 40 to 110°C, preferably from 60 to 90°C, more preferably from 75 to 85°C.

[0036] For the purposes of the present invention, "styrene monomer" means a monomer having at least the chemical structure of styrene.

[0037] Advantageously, the polyether can be chosen from: poly(ethylene oxide), poly(propylene oxide), polyoxymethylene, and their copolymers.

[0038] In one embodiment, the styrenic monomer may include a copolymer group comprising at least two polyethers of different natures.

[0039] Advantageously, the styrenic monomer may comprise a molar mass by weight or molecular weight ranging from 150 to 2000 g / mol, preferably from 200 to 700 g / mol, more preferably from 300 to 450 g / mol.

[0040] In this description, molar mass is considered in terms of weight unless otherwise indicated.

[0041] In one embodiment, the styrenic monomer may comprise at least one motif of the following formula (I):

[0042] where m goes from 3 to 45. Preferably, m goes from 5 to 14.

[0043] In another embodiment, the styrenic monomer may, for example, comprise a poly(ethylene oxide)-poly (propylene oxide) block copolymer group.

[0044] Preferably, in step i), the mixture of a) and b) may comprise from 1 to 10% by moles of free radical initiator relative to the number of moles of styrenic monomers.

[0045] Preferably, the free radical initiator is an azo initiator.

[0046] In the present invention, the term azo initiator means a free radical initiator comprising an azo group in its molecular structure.

[0047] Advantageously, the azo free radical initiator can be selected from: azo-bisisobutyronitrile (AIBN), 1,1'-Azobis(cyclohexanecarbonitrile), 2,2'-Azobis(2-methylbutyronitrile), 4,4'-Azobis(4-cyanovaleric acid), 2,2'-Azobis(2,4-dimethylvaleronitrile) or a mixture of these.

[0048] In one embodiment, the polymer manufacturing process consists of the following steps:

[0049] i) bring into contact:

[0050] a) at least one styrenic monomer comprising at least one polyether; and

[0051] b) a free radical initiator;

[0052] ii) heat the mixture to a temperature ranging from 40 to 110°C, preferably ranging from 60 to 90°C, more preferably ranging from 75 to 85°C.

[0053] Everything described above concerning the polymer in the context of the manufacturing process of said polymer is valid for the polymer that can be obtained by the manufacturing process according to the invention.

[0054] As stated above, the solid polymer electrolyte according to the invention comprises a) at least one polymer as described above, and b) at least one electrolyte salt.

[0055] Advantageously, the electrolyte salt can be chosen from alkaline earth metal salts, alkali metal salts and their mixtures, preferably from alkali metal salts, more preferably from sodium salts, lithium salts and their mixtures, even more preferably from lithium salts.

[0056] Preferably, the electrolyte salt is chosen from LiPF6, LiFSI, LiTFSI, LiC104, LiAsF6, LiBF4, Lil, LiN(CF3SO2)2, LiCF3SO3, LiN(CF3CF2SO2)2, LiCH3SO3, LiN(CF3 SO2)(CF2HSO2), LiN(RFSO2)2, LiC(RFSO2)3, RF being a group chosen from a fluorine atom and a perfluoroalkyl group comprising from one to eight carbon atoms.

[0057] The present invention also relates to a method for preparing a solid polymer electrolyte.

[0058] As mentioned previously, said preparation process comprises the following steps:

[0059] i) bring into contact:

[0060] a) at least one styrenic monomer comprising at least one polyether; and

[0061] b) a free radical initiator;

[0062] ii) heat the mixture comprising a) and b) to a temperature ranging from 40 to 110°C, preferably ranging from 60 to 90°C, more preferably ranging from 75 to 85°C;

[0063] iii) recover the polymer obtained;

[0064] at least one electrolyte salt being added during step i) and / or step iii).

[0065] Preferably, the free radical initiator is an azo initiator.

[0066] Advantageously, the azo free radical initiator can be selected from: azo-bisisobutyronitrile (AIBN), 1,1'-Azobis(cyclohexanecarbonitrile), 2,2'-Azobis(2-methylbutyronitrile), 4,4'-Azobis(4-cyanovaleric acid), 2,2'-Azobis(2,4-dimethylvaleronitrile) or a mixture of these.

[0067] Everything described above concerning the polymer and the process of manufacturing said polymer is valid for the solid polymer electrolyte and the process of manufacturing a solid polymer electrolyte according to the invention.

[0068] Preferably, the heating step ii) takes place over a period of 1 hour to 15 hours, preferably from 3 to 10 hours, more preferably from 4 to 8 hours.

[0069] The electrolyte salt can be added either during step (i) of contacting a) and b), or during step (iii) during recovery of the polymer obtained, or during step (i) and also step (iii).

[0070] Preferably, the electrolyte salt is added during step i) of contacting.

[0071] In addition, step i) of contacting can take place in the presence of a solvent, such as for example tetrahydrofuran (THF) or dichloromethane.

[0072] Advantageously, the styrenic monomer comprises a molar mass ranging from 150 to 2000 g / mol, preferably from 200 to 700 g / mol, more preferably from 300 to 450 g / mol.

[0073] Preferably, 1 to 10 mole percent of free radical initiator relative to the number of moles of styrenic monomers is brought into contact with said monomer styrenic.

[0074] In one embodiment, said styrenic monomer comprises at least one motif of the following formula (I):

[0075] where m goes from 3 to 45. Preferably, m goes from 5 to 14.

[0076] Advantageously, said electrolyte salt can be chosen from alkaline earth metal salts, alkali metal salts and mixtures thereof, preferably from alkali metal salts, more preferably from sodium salts, lithium salts and mixtures thereof, even more preferably from lithium salts.

[0077] Preferably, said electrolyte salt is selected from LiPF6, LiFSI, LiTFSI, LiClO4, LiAsF6, LiBF4, Lil, LiCF3SO3, LiN(CF3CF2SO2)2,LiCH3SO3, LiN(CF3SO2)(CF2HSO2), LiN(RFSO2)2, LiC(RFSO2)3, RF being a group selected from a fluorine atom and a perfluoroalkyl group comprising from one to eight carbon atoms.

[0078] The invention also relates to an all-solid battery cell comprising at least one solid polymer electrolyte according to the invention as defined above.

[0079] Another object of the present invention is an all-solid-state battery comprising at least one cell as defined above.

[0080] The present invention is illustrated in a non-limiting manner by the following examples.

[0081] The polymer according to the invention is therefore a particularly suitable candidate for an application, according to one example, as a polymer for solid polymer electrolyte within an all-solid battery.

[0082] Another object of the invention is also a membrane comprising at least one polymer according to the invention as described above.

[0083] Advantageously, said membrane can be a membrane of a gas separation device, a membrane of a carbon storage device, or even a membrane of a drug delivery device. Examples

[0084] Example 1: Preparation of a polymer by controlled radical polymerization

[0085] In a 25 mL bottle equipped with a stir bar, 0.0278 g, i.e., 7.3 x 10⁻⁵ mol and 1 Eq. of alkoxyamine sold by Arkema under the name BlocBuilder® commercial and the following formula:

[0086] The bottle is closed with a rubber septum, degassed to remove oxygen, then 2 mL of degassed anisole is added into the bottle using a degassed syringe.

[0087] 1.9862 g, i.e. 3.6 x 10⁻³ mol, 50 Eq. of 4-vinylbenzyl methoxynona(ethylene glycol ether (also known as PEGylated styrene) is added to the solution while stirring, which is then purged for 10 min to remove any residual oxygen.

[0088] The bottle was then placed in an oil bath preheated to 120°C.

[0089] The kinetics of the polymerization reaction was monitored at regular intervals by Nuclear Magnetic Resonance (NMR) spectroscopy using an argon exchange syringe to remove samples from the reaction medium.

[0090] After a polymerization time of 360 min, the bottle was removed from the oil bath and the mixture was allowed to cool to room temperature.

[0091] The anisole was then removed using a rotary evaporator and the remaining polymer obtained was purified by dialysis with water using a membrane having a molecular weight cut-off between 6000 and 8000 g / mol.

[0092] Using NMR spectroscopy, it was found that the final conversion rate of the monomer was 0.92.

[0093] The purified polymer obtained was characterized by size exclusion chromatography (SEC). Its number molar mass (Mn) is 19500 g.mol'.

[0094] It has been observed that the polymer obtained is soluble in water, dimethyl sulfoxide (DMSO), and organic solvents such as tetrahydrofuran (THF).

[0095] Example 2: Preparation of a polymer according to the invention

[0096] 1) Formation of a strenic monomer comprising a polv(ethylene oxide):

[0097] 1 equivalent (Eq.) of poly(ethylene glycol) monomethyl ether of molar mass equal to 350g / mol was dissolved in dry THF, then 1.5 Eq of NaH was then slowly added under an argon atmosphere.

[0098] The mixture was stirred for 3 hours until its color turned intense yellow.

[0099] 1.5 Eq. of 4-vinylbenzyl chloride was then added dropwise while stirring vi Stir the mixture thoroughly for 24 hours.

[0100] The crude product obtained was purified several times by several washes with water and n-hexane. The aqueous solution was collected and then the water it contained was removed using a rotary evaporator.

[0101] The resulting liquid was dissolved in dichloromethane (DCM) and then dried with sodium sulfate.

[0102] After removing the DCM, a yellow liquid comprising the monomer 4-vinylbenzyl methoxynona(ethylene glycol) ether was obtained and its purity was determined by NMR spectroscopy.

[0103] 2) Formation of the polymer by free radical polymerization according to the invention

[0104] 35 mg of thermal initiator azobisisobutyronitrile (AIBN) were dissolved in 1 g, i.e. 10% by moles, of 4-vinylbenzyl methoxynona(ethylene glycol) ether monomer previously prepared in step 1), the molar mass of the poly(ethylene oxide) chain of which is 350 g / mol.

[0105] The mixture was then placed in an oven at 65°C for 6 hours.

[0106] A yellow-colored and particularly flexible polymer was obtained.

[0107] Surprisingly, it was found that this polymer is insoluble in many common solvents such as water, DMSO, DCM, DMF, anisole, NMP, ethyl acetate, ethanol, and THF.

[0108] It has been observed that in the presence of such solvents, the polymer obtained swells by absorbing part of the solvent.

[0109] The polymer according to the invention is therefore a particularly suitable candidate for an application, according to one example, as a polymer for solid polymer electrolyte within an all-solid battery.

[0110] Moreover, such a polymer can be used to retain solvent. [YES] Example 3: preparation of a solid polymer electrolyte according to the invention

[0112] 35 mg of azobisisobutyronitrile (AIBN) thermal initiator, LiTFSI and 1 g of 4-vinylbenzyl methoxynona(ethylene glycol) ether monomer as previously prepared in step 1) of Example 2, the poly(ethylene oxide) chain molar mass of which is 350 g / mol, were dissolved in THF solvent.

[0113] THF was used to improve the homogeneity of the solution.

[0114] The resulting solution was poured onto a PTFE Teflon® sheet and then stored until the solvent evaporates.

[0115] The mixture was then placed in an oven at 65°C for 6 hours.

Claims

Demands

1. A process for manufacturing a polymer comprising the following steps: i) bringing into contact: a) at least one styrenic monomer comprising at least one polyether, the styrenic monomer comprising at least one motif of the following formula (I): where m ranges from 3 to 45, preferably from 5 to 14; and b) a free radical initiator; ii) heat the mixture to a temperature ranging from 40 to 110°C, preferably from 60 to 90°C, more preferably from 75 to 85°C.

2. A method according to claim 1, wherein the polyether is selected from: poly(ethylene oxide), poly(propylene oxide), poly-oxymethylene and their copolymers.

3. Method according to claim 1 or 2, step ii) takes place over a period of 1 hour to 15 hours, preferably 3 to 10 hours, more preferably 4 to 8 hours.

4. A process according to any one of claims 1 to 3, wherein said styrenic monomer comprises a molar mass by weight of 150 to 2000 g / mol, preferably 200 to 700 g / mol, more preferably 300 to 450 g / mol.

5. A process according to any one of claims 1 to 4, wherein the free radical initiator is an azo initiator, preferably selected from: azobisisobutyronitrile (AIBN), 1,1'-Azobis(cyclohexanecarbonitrile), 2,2'-Azobis(2-methylbutyronitrile), 4,4'-Azobis(4-cyanovaleric acid), 2,2'-Azobis(2,4-dimethylvaleronitrile) or a mixture thereof.

6. Polymer obtainable by a manufacturing process according to

7.

8.

9.

10. any one of claims 1 to 5. Solid polymer electrolyte comprising a polymer as defined in claim 6, and at least one electrolyte salt. Electrolyte according to claim 7, wherein said electrolyte salt is selected from alkaline earth metal salts, alkali metal salts and mixtures thereof, preferably from alkali metal salts, more preferably from sodium salts, lithium salts and mixtures thereof, even more preferably from lithium salts. Electrolyte according to claim 7 or 8, wherein said electrolyte salt is selected from LiPF6, LiFSI, LiTFSI, LiC104, LiAsF6, LiBF4, Lil, LiCF 3SO3, LiN(CF3CF2SO2)2, LiCH3SO3, LiN(CF3SO2)(CF2HSO2), LiN(RFSO2)2, LiC(RFSO2)3, RF being a group selected from a fluorine atom and a perfluoroalkyl group comprising from one to eight carbon atoms. A process for manufacturing a solid polymer electrolyte comprising the following steps: i) bringing into contact: a) at least one styrenic monomer comprising at least one polyether, the styrenic monomer comprising at least one motif of the following formula (I):

11. where m ranges from 3 to 45, preferably from 5 to 14; and b) an initiator of free radicals; ii) heat the mixture to a temperature ranging from 40 to 110°C, preferably ranging from 60 to 90°C, more preferably ranging from 75 to 85°C; iii) recover the polymer obtained; at least one electrolyte salt being added during step i) and / or step iii). A process according to claim 10, wherein step ii) takes place over a period of 1 to 15 hours, preferably from 3 to 10 hours, more preferably from 4 to 8 hours.

12. A process according to claim 10 or 11, wherein said styrenic monomer comprises a molar mass of 150 to 2000 g / mol, preferably 200 to 700 g / mol, more preferably 300 to 450 g / mol.

13. A method according to any one of claims 10 to 12, wherein the free radical initiator is an azo initiator, preferably selected from: azobisisobutyronitrile (AIBN), 1,1'-Azobis(cyclohexanecarbonitrile), 2,2'-Azobis(2-methylbutyronitrile), 4,4'-Azobis(4-cyanovaleric acid), 2,2'-Azobis(2,4-dimethylvaleronitrile) or a mixture thereof

14. All-solid-state battery cell comprising at least one solid polymer electrolyte as defined in any one of claims 7 to Q

15. y. All-solid-state battery comprising at least one cell as defined in claim 14.