Polymer electrolyte with improved ionic conductivity and mechanical strength and method of manufacturing the same

Abstract

The present disclosure relates to a polymer electrolyte having improved ionic conductivity and mechanical strength and a manufacturing method thereof, and in particular to an ionic gel having improved ionic conductivity and mechanical strength, a polymer electrolyte including the ionic gel, and a manufacturing method thereof. The manufacturing method of the ionic gel is capable of simply and effectively manufacturing a polymer matrix through a one-pot reaction, thus exhibiting a simple processing step, thereby exhibiting excellent processing efficiency and generating economic benefits. Furthermore, although the glass transition temperature (Tg) of a monomer included in the polymer matrix is low, the polymer electrolyte including the ionic gel can still exhibit excellent ionic conductivity and mechanical strength.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an ionic gel having improved ionic conductivity and mechanical strength, synthesis of a polymer constituting the same, and a manufacturing method thereof. BACKGROUND

[0002] The statements in this section merely provide background information related to the present disclosure and do not constitute the related art.

[0003] Lithium ion batteries are energy storage devices having a wide range of applications from small electronic products to electric vehicles, and have a very high potential applicability. All of the positive / negative materials, films, electrolytes, etc. included in the lithium ion battery can affect the performance of the lithium ion battery and are being actively researched, but the research on the electrolyte is relatively insufficient.

[0004] Meanwhile, the electrolyte is a basic component for various electrochemical devices such as electrolyte gate transistors, triboelectric devices, and electrochromic (EC) or electrochemiluminescent devices, as well as lithium ion batteries.

[0005] In particular, ionic conductivity and mechanical strength are two important factors in evaluating electrolytes. High ionic conductivity directly leads to low voltage operation (i.e., low voltage drop) and fast response of electrochemical devices. In addition, unlike conventional liquid electrolytes having a leakage problem, the use of a polymer gel electrolyte (PGE) having high mechanical strength can enable a flexible or stretchable device. However, the two characteristics usually have a trade-off relationship. Therefore, designing and manufacturing a balanced PGE is a challenge to high-performance electrochemical devices.

[0006] Existing physically cross-linked ionic gels have excellent ionic conductivity at room temperature and exhibit moderate mechanical strength (elastic modulus of several thousand pascals). In order to exhibit such performance, it is important that IL-insoluble spheres are directly connected by a small amount of a middle block to form a network structure. In this regard, an ABC triblock copolymer having A and C blocks of IL insolubility is suitable, and an AB diblock copolymer cannot be used as an effective polymer host. Specifically, in order to increase the mechanical modulus without sacrificing ionic conductivity, IL-insoluble blocks can be selectively chemically cross-linked, but this complicates the synthesis of the copolymer.

[0007] Therefore, it is desirable to develop a copolymer that can be easily synthesized and has excellent ionic conductivity and mechanical strength, and an ionic gel and an electrolyte including the same. SUMMARY

[0008] The present disclosure provides an ionic gel including a polymer matrix including a random copolymer having excellent ionic conductivity and mechanical strength, and an ionic liquid and a polymer electrolyte.

[0009] The present disclosure also provides a method of simply synthesizing a polymer matrix including a random copolymer through a one-pot reaction, and manufacturing an ionic gel including the polymer matrix and a polymer electrolyte including the ionic gel.

[0010] The present disclosure is not limited to the foregoing, and will be clearly understood through the following description and implemented by the means described in the present invention and combinations thereof.

[0011] One aspect of the present disclosure provides an ionic gel including a polymer matrix and an ionic liquid, the polymer matrix including a random copolymer having a repeating unit represented by the following Chemical Formula 1 and a repeating unit represented by the following Chemical Formula 2:

[0012] [Chemical Formula 1]

[0013]

[0014] [Chemical Formula 2]

[0015]

[0016] each R 11 is independently selected from the group consisting of a halogen group, a nitrile group, a nitro group, an amine group, a substituted or unsubstituted C1-C 10 alkyl group, a substituted or unsubstituted C1-C 10 alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, and combinations thereof;

[0017] n 11 is 0 to 5;

[0018] R 12 is selected from the group consisting of hydrogen, a halogen group, a nitrile group, a nitro group, an amine group, a substituted or unsubstituted C1-C 10 alkyl group, a substituted or unsubstituted C1-C 10 alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, and combinations thereof;

[0019] R 21 is selected from the group consisting of hydrogen, a halogen group, a nitrile group, a nitro group, an amine group, a substituted or unsubstituted C1-C 10 alkyl group, a substituted or unsubstituted C1-C 10 alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, and combinations thereof;

[0020] R 22 is selected from the group consisting of a substituted or unsubstituted C1-C 12alkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, and combinations thereof;

[0021] R 11 to R 22 each independently is selected from the group consisting of halogen, cyano, nitro, hydroxyl, C1-C8 alkyl, and combinations thereof; and

[0022] n 1 and n 2 each independently is a molar ratio of the repeating units, n 1 + n 2 = 1, where n 1 is a real number from 0.30 to 0.57, and n 2 is a real number from 0.43 to 0.70.

[0023] The ionic gel can include 30 to 60 wt% of the polymer matrix and 40 to 70 wt% of the ionic liquid.

[0024] The copolymer can have a weight average molecular weight (M w ) of 100,000 to 500,000 g / mol, or a number average molecular weight (M n ) of 100,000 to 450,000 g / mol.

[0025] The ionic liquid can be selected from the group consisting of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMI][TFSI]), 1-ethyl-3-methylimidazolium hexafluorophosphate ([EMI][PF6]), 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMI][BF4]), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BMI][TFSI]), 1-butyl-3-methylimidazolium hexafluorophosphate ([BMI][PF6]), 1-butyl-3-methylimidazolium tetrafluoroborate ([BMI][BF4]), and combinations thereof.

[0026] The ionic gel can have a conductivity of 0.50 to 0.60 mS / cm and an elastic modulus of 1.3 x 10 4 to 5.6 x 10 4 Pa.

[0027] Another aspect of the disclosure provides a polymer electrolyte including the above ionic gel and a metal salt.

[0028] The polymer electrolyte can include 30 to 60 wt% of the polymer matrix, 38 to 68 wt% of the ionic liquid, and 1.5 to 7.0 wt% of the metal salt.

[0029] The metal of the metal salt can be selected from the group consisting of lithium (Li), sodium (Na), potassium (K), calcium (Ca), and combinations thereof.

[0030] The polymer electrolyte can have an electrical conductivity of 0.50 to 0.80 mS / cm and a modulus of elasticity of 2.0 x 10 4 to 4.0 x 10 4 Pa.

[0031] Another aspect of the present disclosure provides a method of manufacturing an ionic gel, the method including manufacturing a polymer matrix including a random copolymer obtained by random polymerization of a monomer represented by the following Chemical Formula 3 and a monomer represented by the following Chemical Formula 4, and mixing the polymer matrix with an ionic liquid:

[0032] [Chemical Formula 3]

[0033]

[0034] [Chemical Formula 4]

[0035]

[0036] each R 11 is independently selected from the group consisting of a halogen group, a nitrile group, a nitro group, an amine group, a substituted or unsubstituted C1-C 10 alkyl group, a substituted or unsubstituted C1-C 10 alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, and combinations thereof;

[0037] n 11 is 0 to 5;

[0038] R 12 to R 14 is selected from the group consisting of hydrogen, a halogen group, a nitrile group, a nitro group, an amine group, a substituted or unsubstituted C1-C 10 alkyl group, a substituted or unsubstituted C1-C 10 alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, and combinations thereof;

[0039] R 21 , R 23 , and R 24 is selected from the group consisting of hydrogen, a halogen group, a nitrile group, a nitro group, an amine group, a substituted or unsubstituted C1-C 10 alkyl group, a substituted or unsubstituted C1-C 10 alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, and combinations thereof;

[0040] R 22 is selected from the group consisting of a substituted or unsubstituted C1-C12 alkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, and combinations thereof;

[0041] R 11 to R 24 each of the substituents of R

[0042] The manufacturing of the polymer matrix can be performed by a one-pot reaction.

[0043] The monomer represented by Chemical Formula 4 can have a glass transition temperature (Tg) of -45 to -55℃.

[0044] Another aspect of the present disclosure provides a method of manufacturing a polymer electrolyte, the method including mixing the ion gel manufactured by the above-described method with a metal salt.

[0045] According to the present disclosure, since the method of manufacturing the ion gel is capable of simply and efficiently manufacturing the polymer matrix by a one-pot reaction, the process step is simple and thus exhibits excellent process efficiency and generates economic benefits.

[0046] Also, according to the present disclosure, although the glass transition temperature (Tg) of the monomer used to synthesize the polymer matrix is low, the polymer electrolyte including the ion gel of the present disclosure can still exhibit excellent ionic conductivity and mechanical strength.

[0047] The effects of the present disclosure are not limited to the aforementioned, and it should be understood to include all effects that can be reasonably expected from the following description.

[0048] Other applicable fields will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0049] In order for the present disclosure to be well understood, various forms thereof will now be described, by way of example, with reference to the drawings in which:

[0050] Figure 1 is a flowchart showing the manufacturing of an ion gel and a polymer electrolyte according to the present disclosure;

[0051] Figure 2 is a graph showing the H NMR spectrum of Ps-r-PBA; 1 H NMR spectrum;

[0052] FIG. 3A is an image confirming whether a uniform gel system of the ion gel manufactured using the composition of Comparative Example 2 is achieved;

[0053] FIG. 3B is an image confirming whether a uniform gel system of an ion gel manufactured using the composition of Comparative Example 1 is achieved;

[0054] FIG. 3C is an image confirming whether a uniform gel system of an ion gel manufactured using the composition of Example 2-1 is achieved;

[0055] FIG. 4A is a graph showing measurement results of ionic conductivity of ion gels manufactured using the compositions of Example 2-2 and Comparative Examples 3 and 4;

[0056] FIG. 4B is a graph showing measurement results of elastic modulus of ion gels manufactured using the compositions of Example 2-2 and Comparative Examples 3 and 4;

[0057] FIG. 5A is a graph showing measurement results of ionic conductivity of ion gels manufactured in Examples 1, 2-1, 2-2 using the same styrene composition but having different molecular weights;

[0058] FIG. 5B is a graph showing measurement results of elastic modulus of ion gels manufactured in Examples 1, 2-1, 2-2 using the same styrene composition but having different molecular weights;

[0059] Figure 6 FIG. 6 is a graph showing measurement results of ionic conductivity of ion gels manufactured in Example 2-1 using a monomer having a low glass transition temperature and in Comparative Example 5 using a monomer having a high glass transition temperature;

[0060] FIG. 7A is a graph showing measurement results of ionic conductivity of polymer electrolytes manufactured using the metal salts of Examples 3-1 to 3-4; and

[0061] FIG. 7B is a graph showing measurement results of elastic modulus of polymer electrolytes manufactured using the metal salts of Examples 3-1 to 3-4.

[0062] The accompanying drawings described herein are for purposes of illustration only and are not intended to limit the scope of the present disclosure in any way. DETAILED DESCRIPTION

[0063] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. Variations of the present disclosure are provided for thorough explanation and full disclosure of the present disclosure to those skilled in the art.

[0064] It should be understood that the terms "comprise", "comprising", "include", "including", "have" and "having" when used in this specification, specify the presence of stated features, integers, steps, operations, elements, components or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components or combinations thereof.

[0065] Unless otherwise indicated, all numbers, values and / or expressions representing quantities of components, reaction conditions, polymer compositions and mixtures used herein are to be understood to be modified in all instances by the term "about", inasmuch as various inherent uncertainties are present in the measurement of these values, and therefore, it is understood that in all cases, the numerical values are to be construed in accordance with the foregoing. Furthermore, when disclosing numerical ranges, unless otherwise indicated, the range is continuous and includes all values from the lowest value to the highest value of the range. Further, when the range is an integer value, unless otherwise indicated, all integers within the range are included.

[0066] Unless otherwise indicated herein, the term "C1-C 10 Alkyl" means a primary to tertiary alkyl group having 1 to 10 carbon atoms. Alkyl groups can be, for example, functional groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, n-hexyl, and the like.

[0067] Unless otherwise indicated herein, the term "C1-C 10 Alkoxy" means an -O-R group, wherein R includes "C1-C 10 Alkyl", "aryl", "heteroaryl", or "benzyl". Examples of alkoxy groups include methoxy, ethoxy, phenoxy, benzyloxy, and the like.

[0068] Unless otherwise indicated herein, the term "aryl" means a chemical group obtained by removing a hydrogen atom from a monocyclic or polycyclic compound having 2 to 30 carbon atoms and its derivative containing at least one benzene ring. For example, monocyclic or polycyclic compounds containing a benzene ring include a benzene ring, toluene or xylene in which an alkyl side chain is attached to a benzene ring, a biphenyl group in which two or more benzene rings are bonded by a single bond, fluorene, xanthene or anthraquinone in which a benzene ring is fused with a cycloalkyl group or a heterocyclic alkyl group, and naphthalene or anthracene in which two or more benzene rings are fused.

[0069] Unless otherwise indicated herein, the prefix "hetero" means 1 to 3 heteroatoms selected from -N-, -O-, -S-, and -P- substituting carbon atoms. Examples thereof can include pyridine, pyrrole, or carbazole containing a nitrogen atom as a heteroatom, furan or dibenzofuran containing an oxygen atom as a heteroatom, dibenzothiophene, diphenylamine, and the like.

[0070] Unless otherwise indicated herein, the term "halogen group" refers to a Group 17 element, and can be, for example, a fluorine group, a chlorine group, a bromine group, or an iodine group.

[0071] Unless otherwise indicated herein, a bond line between the ends of a chemical formula without a substituent represents a moiety in which the compound is attached to another compound.

[0072] Ionic gel

[0073] According to one form of the present disclosure, the ionic gel includes a polymer matrix including a random copolymer and an ionic liquid.

[0074] Specifically, the ionic gel according to the present disclosure includes 30 to 60 wt% of the polymer matrix and 40 to 70 wt% of the ionic liquid. If the amount of the polymer matrix is less than 30 wt%, it can be impossible to obtain sufficient mechanical strength. On the other hand, if the amount thereof exceeds 60 wt%, the ionic conductivity can decrease. In addition, if the amount of the ionic liquid is less than 40 wt%, the ionic conductivity can decrease. On the other hand, if the amount thereof exceeds 70 wt%, the mechanical strength can decrease.

[0075] Accordingly, the ionic gel manufactured according to the present disclosure is configured such that the polymer matrix including the random copolymer and the ionic liquid are uniformly mixed, and has an electrical conductivity of 0.50 to 0.60 mS / cm and an elastic modulus of 1.3 x 10 4 to 5.6 x 10 4 , ultimately resulting in excellent ionic conductivity and mechanical strength.

[0076] Polymer matrix

[0077] In one form of the present disclosure, the polymer matrix includes a random copolymer having a repeating unit represented by the following Chemical Formula 1 and a repeating unit represented by the following Chemical Formula 2.

[0078] [Chemical Formula 1]

[0079]

[0080] [Chemical Formula 2]

[0081]

[0082] Here, each R 11 is independently selected from the group consisting of a halogen group, a nitrile group, a nitro group, an amine group, a substituted or unsubstituted C1-C 10 alkyl group, a substituted or unsubstituted C1-C 10 alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, and combinations thereof.

[0083] R 11 substituted for the hydrogen of the benzene ring, and when n 11 is 0, all sites of the benzene ring are substituted with hydrogen, and when the benzene ring contains R 11 , the remaining sites are substituted with hydrogen, as would be apparent to one skilled in the art to which this disclosure pertains. When n 11 is 2 or more, R 11 may be the same or different substituents. Hereinafter, since the same is true for other substituents substituted in the benzene ring, redundant descriptions thereof will be omitted.

[0084] R 12 is selected from the group consisting of hydrogen, a halogen group, a nitrile group, a nitro group, an amine group, a substituted or unsubstituted C1-C 10 alkyl group, a substituted or unsubstituted C1-C 10 alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, and combinations thereof.

[0085] R 21 is selected from the group consisting of hydrogen, a halogen group, a nitrile group, a nitro group, an amine group, a substituted or unsubstituted C1-C 10 alkyl group, a substituted or unsubstituted C1-C 10 alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, and combinations thereof.

[0086] R 22 is selected from the group consisting of a substituted or unsubstituted C1-C 12 alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, and combinations thereof, and is preferably a substituted or unsubstituted C1-C4 alkyl group.

[0087] In the substituents of R 11 to R 22 , hydrogen can be substituted with any one selected from the group consisting of a halogen group, a hydroxyl group, a carboxyl group, a cyano group, a nitro group, an amine group, a sulfide group, a methylthio group, an alkoxy group, a nitrile group, an aldehyde group, an epoxy group, an ether group, an ester group, a carbonyl group, an acetal group, a ketone group, an alkyl group, a perfluoroalkyl group, a cycloalkyl group, a heterocycloalkyl group, a benzyl group, an aryl group, a heteroaryl group, derivatives thereof, and combinations thereof, and is preferably substituted with a halogen group, a cyano group, a nitro group, or a C1-C8 alkyl group.

[0088] In addition, n 1 and n 2 are each independently a molar ratio of the repeating unit represented by Chemical Formula 1 to the repeating unit represented by Chemical Formula 2, n 1 +n 2 = 1, where n 1 is a real number of 0.30 to 0.57 and n 2is a real number of 0.43 to 0.70. Particularly, n 1 may be a real number of 0.39 to 0.53, and n 2 may be a real number of 0.47 to 0.61. If n 1 is less than 0.30 or n 2 is greater than 0.70, the mechanical strength can decrease. On the other hand, if n 1 is greater than 0.57 or n 2 is less than 0.43, it can be impossible to form an ion gel, or a polymer electrolyte including the ion gel can become non-uniform.

[0089] The copolymer included in the polymer matrix can be a random copolymer formed by randomly connecting the repeating unit represented by Chemical Formula 1 and the repeating unit represented by Chemical Formula 2, or can be a block copolymer consisting of a block having the repeating unit represented by Chemical Formula 1 and a block having the repeating unit represented by Chemical Formula 2, and is preferably a random copolymer. Since the copolymer is a random copolymer, its manufacture is simple compared to a method of synthesizing a block copolymer, and both its ionic conductivity and mechanical properties can be excellent.

[0090] As used herein, the term "random copolymer" refers to a copolymer in which different monomers are randomly distributed irregularly along a chain, rather than an alternating copolymer in which different monomers are regularly arranged alternately.

[0091] The copolymer can have a weight average molecular weight (M w ) of 100,000 to 500,000 g / mol and a number average molecular weight (M n ) of 100,000 to 450,000 g / mol, and preferably a weight average molecular weight (M w ) of 268,000 to 475,000 g / mol and a number average molecular weight (M n ) of 218,000 to 417,000 g / mol. If the weight average molecular weight of the copolymer is less than 100,000 g / mol, the mechanical strength can decrease. On the other hand, if its weight average molecular weight exceeds 500,000 g / mol, the viscosity is too high to make it difficult to control the polymer synthesis process.

[0092] Specifically, the copolymer according to the present disclosure has excellent ionic conductivity and mechanical properties, and thus can be applied to a high-functioning ion gel. Particularly, when a random copolymer in which the proportion of repeating units constituting the random copolymer and the weight average molecular weight are appropriately adjusted and applied to an ion gel, solubility in an ionic liquid can be maintained and excellent mechanical properties can be produced.

[0093] (2) Ionic liquid

[0094] According to the present disclosure, the ionic liquid is an ionic compound that is liquid at a temperature of 100℃ or less, and can generally be a salt having a melting point equal to or lower than room temperature (20℃ to 25℃). The ionic liquid is not particularly limited as long as it is capable of increasing the ionic conductivity of the ionic gel of the present disclosure.

[0095] The ionic liquid according to the present disclosure can be selected from 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMI][TFSI]), 1-ethyl-3-methylimidazolium hexafluorophosphate ([EMI][PF6]), 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMI][BF4]), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BMI][TFSI]), 1-butyl-3-methylimidazolium hexafluorophosphate ([BMI][PF6]), 1-butyl-3-methylimidazolium tetrafluoroborate ([BMI][BF4]), and combinations thereof, and is preferably 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BMI][TFSI]).

[0096] Polymer electrolyte

[0097] The polymer electrolyte according to the present disclosure is not particularly limited as long as it has excellent ionic conductivity and mechanical strength.

[0098] Specifically, the polymer electrolyte according to the present disclosure can include the above-mentioned ionic gel and a metal salt. The metal included in the metal salt can be, for example, lithium (Li), sodium (Na), potassium (K), or calcium (Ca), and is preferably lithium (Li).

[0099] The polymer electrolyte according to the present disclosure can include the ionic gel of the present disclosure, which includes 30 to 60 wt% of a polymer matrix and 38 to 68 wt% of an ionic liquid, and 1.5 to 7.0 wt% of a metal salt. If the amount of the polymer matrix is less than 30 wt%, it can be impossible to obtain sufficient mechanical strength. On the other hand, if the amount thereof exceeds 60 wt%, the ionic conductivity can decrease.

[0100] The polymer electrolyte according to the present disclosure has an ionic conductivity of 0.50 to 0.80 mS / cm and an elastic modulus of 2.0 x 10 4 to 4.0 x 10 4 Pa, and thus can maintain similar mechanical strength and the ionic conductivity can be increased by 50% or more compared to the prior art.

[0101] Figure 1is a flowchart showing manufacturing of an ion gel and a polymer electrolyte according to the present disclosure. Referring to the figure, the method includes manufacturing a polymer matrix including a random copolymer (S10), manufacturing an ion gel by mixing the polymer matrix with an ionic liquid (S20), and mixing the ion gel with a metal salt (S30).

[0102] In the manufacturing of the polymer matrix (S10), the polymer matrix is manufactured to include a random copolymer obtained by random polymerization of a monomer represented by the following Chemical Formula 3 and a monomer represented by the following Chemical Formula 4.

[0103] [Chemical Formula 3]

[0104]

[0105] [Chemical Formula 4]

[0106]

[0107] Here, R 11 , n 11 , R 12 , R 21 , and R 22 may be the same as or different from the above description of the copolymer, R 13 to R 14 may be the same as or different from R 12 , and R 23 and R 24 may be the same as or different from R 21 .

[0108] According to the present disclosure, the glass transition temperature (Tg) of the monomer represented by Chemical Formula 4 is -45 to -55℃, and is preferably -50℃. Even when a monomer having a low glass transition temperature is used to manufacture a polymer electrolyte, its ionic conductivity can be higher than that of a conventional polymer electrolyte including an ionic liquid having a high ionic conductivity compared to the present disclosure.

[0109] According to the present disclosure, the polymerization of the copolymer can be performed by active anionic polymerization, active cationic polymerization, controlled radical polymerization, RAFT (Reversible Addition-Fragmentation Chain Transfer), ATRP (Atom Transfer Radical Polymerization), NMP (Nitroxide Mediated Polymerization), etc. Preferably, the RAFT method is used for efficient one-pot polymerization. When the RAFT method is used, the above monomers are mixed with 2-(phenylthiocarbonylthio)-2-phenylacetic acid ethyl ester and azobisisobutyronitrile (AIBN), purged with argon at room temperature for 30 minutes to 1.5 hours, and then polymerized at a temperature of 78°C to 82°C. After polymerization, the solution can be optionally quenched with liquid nitrogen and precipitated in excess methanol to provide a polymer, which is then filtered, dried under reduced pressure at a temperature of 30°C to 70°C, and purified. This process can be repeated 2 to 5 times for additional purification.

[0110] The manufacturing of the polymer matrix including the random copolymer according to the present disclosure is performed by one-pot reaction, and there is no additional step of adding a functional group, and thus the ionic gel and the polymer electrolyte according to the present disclosure can be simply and efficiently manufactured, so that the processing steps are simple, and thus the processing efficiency can be improved and economic benefits can be obtained.

[0111] In the manufacturing of the ionic gel (S20) and the mixing of the metal salt (S30), the above manufactured polymer matrix is mixed with an ionic liquid to provide an ionic gel, which is then mixed with a metal salt. The ionic liquid and the metal salt can be the same as or different from the above description of the ionic gel and the polymer electrolyte.

[0112] A better understanding of the present disclosure can be obtained through the following examples, which are set forth by way of illustration and are not intended to limit the scope of the present disclosure.

[0113] Example 1

[0114] (S10) Polystyrene-random-poly(butyl acrylate) (Ps-r-PBA) was synthesized by one-pot RAFT (Reversible Addition-Fragmentation Chain Transfer) polymerization (Scheme 1 below).

[0115] [Scheme 1]

[0116]

[0117] Specifically, monomers (i.e., styrene and butyl acrylate) were purified by passing through a column packed with basic alumina. Next, styrene (12.18 g, 116.93 mmol), butyl acrylate (22.48 g, 175.39 mmol), 2-(phenylthiocarbonylthio)-2-phenylacetic acid ethyl ester (1.93 mg, 0.0061 mmol), and AIBN (0.2 mg, 0.0012 mmol) were put into a flask equipped with a magnetic stir bar. The reaction mixture was purged with argon (Ar) for 1 hour at room temperature, and then reacted at 80°C. After 18 hours, the solution was quenched with liquid nitrogen. The reaction product was precipitated in an excess of methanol to obtain Ps-r-PBA, which was then filtered and dried under reduced pressure at 60°C. This process was repeated three times for further purification. The number average molecular weight (M n ) and the weight average molecular weight (M w ) measured by size exclusion chromatography (SEC) based on PS standards calibration were 417,000 and 475,000, respectively, and the amount of polystyrene contained in Ps-r-PBA was 53.3 mol%.

[0118] (S20) Ps-r-PBA was mixed with 105 mg of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BMI][TFSI]) as an ionic gel liquid.

[0119] As a result, an ionic gel containing 40 wt% of a polymer matrix and 60 wt% of an ionic liquid was manufactured.

[0120] Example 2-1

[0121] An ionic gel was manufactured in the same manner as Example 1, except that the number average molecular weight (M n ) and the weight average molecular weight (M w ) of Ps-r-PBA obtained by adding styrene (6.09 g, 58.46 mmol) and butyl acrylate (11.24 g, 87.70 mmol) were 247,000 and 274,000, respectively.

[0122] Example 2-2

[0123] An ionic gel was manufactured in the same manner as Example 1, except that the number average molecular weight (M n ) and the weight average molecular weight (M w ) of Ps-r-PBA obtained by adding styrene (3.04 g, 29.23 mmol) and butyl acrylate (5.62 g, 43.85 mmol) were 109,000 and 128,000, respectively.

[0124] Example 3-1

[0125] A polymer electrolyte comprising 39.2 wt% polymer matrix, 59 wt% ionic liquid and 1.8 wt% lithium salt was prepared by mixing the ion gel prepared in Example 1 with 3.21 mg of lithium (Li).

[0126] Example 3-2

[0127] A polymer electrolyte comprising 38.6 wt% polymer matrix, 57.9 wt% ionic liquid and 3.5 wt% lithium salt was prepared by mixing the ion gel prepared in Example 1 with 6.35 mg of lithium (Li).

[0128] Example 3-3

[0129] A polymer electrolyte comprising 38.0 wt% polymer matrix, 56.9 wt% ionic liquid and 5.1 wt% lithium salt was prepared by mixing the ion gel prepared in Example 1 with 9.39 mg of lithium (Li).

[0130] Examples 3-4

[0131] A polymer electrolyte comprising 37.3 wt% polymer matrix, 56 wt% ionic liquid and 6.7 wt% lithium salt was prepared by mixing the ion gel prepared in Example 1 with 12.57 mg of lithium (Li).

[0132] Comparative Example 1

[0133] In addition to the number-average molecular weight (M) of Ps-r-PBA obtained by adding styrene (7.61 g, 73.08 mmol) and butyl acrylate (9.37 g, 73.08 mmol), n ) and weight-average molecular weight (M w The ionogels were manufactured in the same manner as in Example 1, except that the amounts of polystyrene contained in Ps-r-PBA were 250,000 and 305,000, respectively, and the amount of polystyrene contained in Ps-r-PBA was 57.2 mol%.

[0134] Comparative Example 2

[0135] In addition to the number-average molecular weight (M) of Ps-r-PBA obtained by adding styrene (9.13 g, 87.70 mmol) and butyl acrylate (7.49 g, 58.46 mmol), n ) and weight-average molecular weight (M w The ionogels were manufactured in the same manner as in Example 1, with the amounts of polystyrene contained in Ps-r-PBA being 218,000 and 268,000, respectively, and the amount of polystyrene contained in Ps-r-PBA being 59.1 mol%.

[0136] Comparative Example 3

[0137] In addition to the number-average molecular weight (M) of Ps-r-PBA obtained by adding styrene (1.52 g, 14.62 mmol) and butyl acrylate (7.49 g, 58.46 mmol), n ) and weight-average molecular weight (M w The ionogels were manufactured in the same manner as in Example 1, with the amounts of polystyrene contained in Ps-r-PBA being 144,000 and 172,000, respectively, and the amount of polystyrene contained in Ps-r-PBA being 39.0 mol%.

[0138] Comparative Example 4

[0139] In addition to the number-average molecular weight (M) of Ps-r-PBA obtained by adding styrene (2.28 g, 21.92 mmol) and butyl acrylate (6.56 g, 51.16 mmol), n ) and weight-average molecular weight (M w The ionogels were prepared in the same manner as in Example 1, except that the amounts of polystyrene contained in Ps-r-PBA were 107,000 and 123,000, respectively, and the amount of polystyrene contained in Ps-r-PBA was 39.0 mol%.

[0140] Comparative Example 5

[0141] In addition to the number-average molecular weight (M) of Ps-r-PMMA obtained by replacing butyl acrylate with methyl methacrylate (11.71 g, 116.93 mmol), n The ionic gel was prepared in the same manner as in Example 1, with a polystyrene content of 29.0 mol% in Ps-r-PMMA and 220,000 g / mol. 1-Ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([EMI][TFSI]) was added as an ionic liquid in place of [BMI][TFSI].

[0142] Test of the properties of the random copolymer prepared in Example 1

[0143] like Figure 2 of 1 The 1H NMR spectrum confirmed the successful synthesis of the random copolymer. Specifically, as shown... Figure 2 As shown, the hydrogen of styrene was confirmed based on the peak and peak area of ​​region a, and the hydrogen of the methyl (CH2) group stripped by the adjacent carbonyl group and oxygen was confirmed based on the peak and peak area of ​​region b, indicating that the Ps-r-PBA according to this disclosure was successfully synthesized.

[0144] Test Example 2 – Implementation conditions depend on the homogeneous ionogel system composed of random copolymers in the polymer matrix.

[0145] To evaluate whether the ionic gels manufactured in Example 2-1 and Comparative Examples 1 and 2 are formed in a uniform system to achieve the ionic gel system, tests were performed.

[0146] As shown in FIGS. 3A and 3B, it was confirmed that the ionic gels manufactured in Comparative Examples 1 and 2 were not in the form of a uniform system.

[0147] As shown in FIG. 3C, it was confirmed that the ionic gel manufactured in Example 2-1 was in the form of a uniform system.

[0148] Therefore, it can be concluded that when the amount of styrene in the random copolymer is 53.7 mol% or less, the resulting ionic gel can be provided in the form of a uniform system.

[0149] Test Example 3 - Change in performance of ionic gel system depending on random copolymer composition in polymer matrix

[0150] The performance of the ionic gels manufactured in Example 2-2 and Comparative Examples 3 and 4, i.e., the conductivity and the elastic modulus, was measured.

[0151] The ionic conductivity of the ionic gels was measured using an electrochemical impedance spectrophotometer (IM6, ZAHNER) with a frequency and AC amplitude of 10 -1 Hz to 10 6 Hz and 10 mV, respectively.

[0152] In the ionic gel containing 40 wt% of Ps-r-PBA, the resistance (R) of the ionic conductivity was measured to be 2721.3 Ω and 3235.2 to 3359.3 Ω. The ionic conductivity calculated using a cylindrical cell (diameter: 4 mm and thickness (h): 2 mm, σ = h / AR (where A is the cross-sectional area)) was 0.52 mS / cm and 0.48 to 0.46 mS / cm.

[0153] The mechanical properties of the ionic gels were measured using a dynamic mechanical analyzer (DMA, Q800, TA instruments, USA). For the compression test, a hexagonal sample (thickness: 1.73 mm and width: 8.00 mm) was used. The stress-strain curve was recorded based on a change in strain from 0% to 20% at a scan rate of 3 N / min, and the elastic modulus was calculated from the slope of the line with respect to the data in the linear region.

[0154] As shown in FIGS. 4A and 4B, when the amount of styrene monomer in the polymer matrix of the ionic gel was increased from 39.0 mol% to 53.7 mol%, the ionic conductivity was about 0.58 mS / cm in Comparative Example 3, about 0.55 mS / cm in Comparative Example 4, and about 0.54 mS / cm in Example 2-2, which were similar, but the elastic modulus was about 1.4 x 10 4 Pa in Comparative Example 3, about 1.7 x 10 4 Pa in Comparative Example 4, and about 2.1 x 10 4 Pa in Example 2-2, which represented a gradual increase.

[0155] Therefore, it can be concluded that the ionic conductivity and mechanical strength of the ionic gel according to the present disclosure are excellent when the amount of styrene monomer therein is about 52 to 55 mol%.

[0156] Test Example 4 - Change in performance of ionic gel system depending on molecular weight of random copolymer in polymer matrix

[0157] The performance of the ionic gel manufactured in Examples 1, 2-1, and 2-2, i.e., ionic conductivity and elastic modulus, was measured.

[0158] The ionic conductivity and elastic modulus of the ionic gel were measured in the same manner as in Test Example 3.

[0159] As shown in FIGS. 5A and 5B, under the condition that the amount of styrene monomer of the polymer matrix of the ionic gel was maintained in the range of 52 to 55 mol%, when the weight average molecular weight (M w ) of the polymer matrix was increased from a low molecular weight (100,000 g / mol to 200,000 g / mol) to a medium molecular weight (200,000 g / mol to 400,000 g / mol) and a high molecular weight (400,000 g / mol or more), the ionic conductivity was about 0.54 mS / cm in Example 2-2, about 0.52 mS / cm in Example 2-1, and about 0.53 mS / cm in Example 1, which were similar, but the elastic modulus was about 2.1 x 10 4 Pa in Example 2-2, about 3.7 x 10 4 Pa in Example 2-1, and about 5.5 x 10 4 Pa in Example 1, which represented an increase of at least 2.5 times compared to Example 2-2.

[0160] Therefore, it can be concluded that the ionic conductivity and mechanical strength of the ionic gel are excellent when the weight average molecular weight (M wWhen the molecular weight falls within the high molecular weight range (470,000 to 490,000 g / mol), the ionic conductivity and mechanical strength of the ionogel containing the polymer matrix are excellent.

[0161] Test Example 5 – Comparison of ionic conductivity with conventional ionogel systems having high glass transition temperatures (Tg)

[0162] To evaluate the ionic conductivity of ionogels that depend on the monomer's Tg, the ionic conductivity values ​​of the ionogels prepared in Examples 2-1 and Comparative Example 5 were compared.

[0163] Ionic conductivity was measured in the same manner as in Test Example 3.

[0164] like Figure 6 As shown, the ionogel of Comparative Example 5 was prepared using [EMI][TFSI] (which is an ionic liquid with a high Tg) as a high glass transition temperature (Tg) system (Tg = 120°C), but exhibited about 1 / 3 of the ionic conductivity of Example 2-1, which included an ionic liquid with a lower Tg as a relatively low glass transition temperature (Tg) system (Tg = -50°C) (ionic conductivity of Comparative Example 5: 0.17 mS / cm, and ionic conductivity of Example 2-2: 0.52 mS / cm).

[0165] Therefore, it can be concluded that the ionogel system disclosed herein is a system manufactured using monomers with low glass transition temperature (Tg) but high ionic conductivity (Tg = -50 °C), resulting in excellent electrochemical performance.

[0166] Test Example 6 - Control of the properties of polymer electrolytes in ionogel systems of this disclosure

[0167] In order to control the properties of polymer electrolytes by mixing the optimal ionogel system confirmed through the above test examples with metal salts, polymer electrolytes were manufactured as in Examples 3-1 to 3-4, and their properties, namely ionic conductivity and elastic modulus, were measured.

[0168] As shown in Figures 7A and 7B, as the amount (wt%) of the metal salt increases, the elastic modulus, which is the mechanical strength, is approximately 3.8 × 10⁻⁶ in Example 3-1. 4 In Example 3-2, it is approximately 2.6 × 10⁻⁶. 4 Pa, in Examples 3-3, is approximately 2.1 × 10⁻⁶. 4 And in Examples 3-4, it is approximately 1.9 × 10⁻⁶. 4which is slightly reduced, but the ionic conductivity as an electrochemical property is about 0.54 mS / cm in Example 3-1, about 0.55 mS / cm in Example 3-2, about 0.69 mS / cm in Example 3-3 and about 0.75 mS / cm in Example 3-4, which is significantly increased.

[0169] Therefore, it can be concluded that the polymer electrolyte system according to the present disclosure is able to control the mechanical property, i.e. the elastic modulus, as well as the electrochemical property, i.e. the ionic conductivity, by adjusting the amount of metal salt while including the optimal ionic gel system.

[0170] Although the variations of the present disclosure have been disclosed for illustrative purposes, those skilled in the art will understand that various modifications can be made without departing from the scope and spirit of the present disclosure disclosed in the appended claims, and such modifications should not be understood separately from the technical idea or desired features of the present disclosure.

Claims

1. An ionic gel comprising: a polymer matrix including a random copolymer having a repeating unit represented by the following Chemical Formula 1 and a repeating unit represented by the following Chemical Formula 2; and an ionic liquid, [Chemical Formula 1] [Chemical Formula 2] Each R 11 Independently selected from halogen groups, nitrile groups, nitro groups, amino groups, substituted or unsubstituted C1-C groups. 10 Alkyl, substituted or unsubstituted C1-C 10 Alkoxy, substituted or unsubstituted aryl, substituted or unsubstituted C5-C 14 The group consisting of heteroaryl groups and their combinations. n 11 is 0 to 5, R 12 selected from the group consisting of hydrogen, a halogen group, a nitrile group, a nitro group, an amine group, a substituted or unsubstituted Ci-C 10 alkyl group, a substituted or unsubstituted Ci-C 10 alkoxy group, a substituted or unsubstituted C5-C 14 aryl group, a substituted or unsubstituted heteroaryl group, and combinations thereof, R 21 selected from the group consisting of hydrogen, a halogen group, a nitrile group, a nitro group, an amine group, a substituted or unsubstituted Ci-C6alkyl group, a substituted or unsubstituted Ci-C6alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, and combinations thereof, 10 a substituted or unsubstituted Ci-C6alkyl group, a substituted or unsubstituted Ci-C6alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, and combinations thereof, 10 a substituted or unsubstituted Ci-C6alkyl group, a substituted or unsubstituted Ci-C6alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, and combinations thereof, R 22 selected from the group consisting of substituted or unsubstituted C1-C 12 alkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, and combinations thereof, R 11 to R 22 each independently is selected from the group consisting of a halogen group, a cyano group, a nitro group, a Ci-C8alkyl group, and combinations thereof, and n 1 and n 2 each independently is a molar ratio of the repeating units, n 1 + n 2 = 1, wherein n 1 is a real number from 0.533 to 0.57 and n 2 is a real number from 0.43 to 0.467, wherein The random copolymer has a weight average molecular weight of 268,000 to 475,000 g / mol, or the random copolymer has a number average molecular weight of 218,000 to 417,000 g / mol. 2.The ionic gel according to claim 1, comprising: 30 to 60 wt% of the polymer matrix; and 40 to 70 wt% of the ionic liquid.

3. The ionic gel according to claim 1, wherein, The ionic liquid is selected from the group consisting of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-ethyl-3-methylimidazolium hexafluorophosphate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium tetrafluoroborate, and combinations thereof.

4. The ionic gel of claim 1 having a conductivity of 0.50 to 0.60 mS / cm and a modulus of elasticity of 1.3 x 10 4 to 5.6 x 10 4 Pa. 5.A polymer electrolyte comprising the ionic gel of claim 1 and a metal salt. 6.The polymer electrolyte according to claim 5, comprising: 30 to 60 wt% of the polymer matrix; 38 to 68 wt% of the ionic liquid; and 1.5 to 7.0 wt% of the metal salt.

7. The polymer electrolyte according to claim 5, wherein, The metal of the metal salt is selected from the group consisting of lithium, sodium, potassium, calcium, and combinations thereof.

8. The polymer electrolyte according to claim 5, having an electrical conductivity of 0.50 to 0.80 mS / cm and an elastic modulus of 2.0 x 10 4 to 4.0 x 10 4 Pa. 9.A method of manufacturing an ionic gel, the method comprising: manufacturing a polymer matrix including a random copolymer obtained by randomly polymerizing a monomer represented by the following Chemical Formula 3 and a monomer represented by the following Chemical Formula 4; and manufacturing an ionic gel by mixing the polymer matrix with an ionic liquid, [Chemical Formula 3] [Chemical Formula 4] wherein each R 11 is independently selected from the group consisting of a halogen group, a nitrile group, a nitro group, an amine group, a substituted or unsubstituted Ci-C6alkyl group, a substituted or unsubstituted C1-C6alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, and combinations thereof, 10 is independently selected from the group consisting of a halogen group, a nitrile group, a nitro group, an amine group, a substituted or unsubstituted Ci-C6alkyl group, a substituted or unsubstituted C1-C6alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, and combinations thereof, 10 is independently selected from the group consisting of a halogen group, a nitrile group, a nitro group, an amine group, a n 11 is 0 to 5, R 12 to R 14 selected from the group consisting of hydrogen, a halogen group, a nitrile group, a nitro group, an amine group, a substituted or unsubstituted Ci-C 10 alkyl group, a substituted or unsubstituted Ci-C 10 alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, and combinations thereof, R 21 R 23 and R 24 Choose from hydrogen, halogen groups, nitrile groups, nitro groups, amino groups, and substituted or unsubstituted C1-C groups. 10 Alkyl, substituted or unsubstituted C1-C 10 The group consisting of alkoxy groups, substituted or unsubstituted aryl groups, substituted or unsubstituted heteroaryl groups, and combinations thereof. R 22 substituted or unsubstituted C1-C6alkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, and combinations thereof, and 12 substituted or unsubstituted C1-C6alkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, and combinations thereof, and R 11 to R 24 each independently is a halogen group, a cyano group, a nitro group, or a Ci-C8alkyl group, wherein a molar ratio of the monomer represented by Chemical Formula 3 and the monomer represented by Chemical Formula 4 is 0.533 to 0.57:0.43 to 0.467, and a sum of the molar ratio of the monomer represented by Chemical Formula 3 and the monomer represented by Chemical Formula 4 is 1, wherein the random copolymer has a weight average molecular weight of 268,000 to 475,000 g / mol, or the random copolymer has a number average molecular weight of 218,000 to 417,000 g / mol.

10. The method of claim 9, wherein, The manufacturing of the polymer matrix is performed by a one-pot reaction.

11. The method of claim 9, wherein, The monomer represented by Chemical Formula 4 has a glass transition temperature of -45 to -55℃.

12. The method of claim 9, wherein, The ionic liquid is selected from the group consisting of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-ethyl-3-methylimidazolium hexafluorophosphate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium tetrafluoroborate, and combinations thereof. 13.A method of manufacturing a polymer electrolyte, the method comprising mixing an ionic gel manufactured by the method of claim 9 with a metal salt.

14. The method of claim 13, wherein, The metal of the metal salt is selected from the group consisting of lithium, sodium, potassium, calcium, and combinations thereof. The metal of the metal salt is selected from the group consisting of lithium, sodium, potassium, calcium, and combinations thereof.

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