Ion-conducting polymers for gel polymer electrolytes, and gel polymer electrolytes containing such ion-conducting polymers.

Abstract

This invention provides an ion-conducting polymer (GPE) for gel polymer electrolytes that combines excellent ion conductivity, high thermal stability and heat resistance, and excellent resistance to high voltage. [Solution] The present invention provides a repeating unit according to formula (I), and -R1 on N of the complex ring of formula (I) is -R5-S(O)2-N - -S(O)2-CF3M + The repeating unit that was replaced by TIFF2026057507000022.tif34170 Regarding ion-conducting polymers for gel polymer electrolytes, R1 is (CH2); R2 and R5 are individually C1~C 10 Alkyl or C2-C 10 Alkenyl; M is an alkali metal or alkaline earth metal. The present invention further relates to a gel polymer electrolyte containing an ion-conducting polymer, and a method for producing an ion-conducting polymer.

Description

[Technical Field]

[0001] The present invention relates to an ion-conducting polymer for use in a battery gel polymer electrolyte. The present invention further relates to a gel polymer electrolyte containing such an ion-conducting polymer, and to a method for producing an ion-conducting polymer. [Background technology]

[0002] Over the past decade, the shift from liquid electrolytes in batteries to non-liquid electrolytes such as gel polymer electrolytes and solid electrolytes has attracted considerable attention. This shift offers significant advantages, including improved safety by reducing the risk of leakage and fire, as well as improved battery life and performance through enhanced structural stability and reduced degradation.

[0003] Gel polymer electrolytes (GPEs) are attracting considerable attention due to their unique properties, which combine the mechanical stability of a solid with the ionic conductivity of a liquid. The polymer matrix is ​​a crucial component in these electrolytes because it helps to provide a certain degree of flexibility to the electrolyte while maintaining structural integrity, and also improves ionic conductivity, thereby enhancing battery performance and lifespan.

[0004] However, while gel polymer electrolytes have better ionic conductivity than solid electrolytes, it is still lower than liquid electrolytes, which can limit the performance of batteries containing such gel polymer electrolytes. Furthermore, problems related to long-term stability and compatibility with electrode materials are more likely to occur, potentially affecting the efficiency and lifespan of energy storage systems. Additionally, the addition of plasticizers, and sometimes solvents, can lead to phase separation and crystallization, which can degrade the performance of the GPE over time.

[0005] Patent Document 1 discloses a gel polymer electrolyte comprising a crosslinked network, an ionic liquid, and one or more lithium salts. The crosslinked network is a reaction product of an inorganic polyhedral oligomer silsesquioxane and a functionalized poly(ethylene glycol) or functionalized poly(ethylene oxide) and an amine-terminal functionalized poly(ethylene glycol) or amine-terminal functionalized poly(ethylene oxide).

[0006] Patent Document 2 discloses an ion-conducting polymer binder that binds an inorganic solid electrolyte, thereby reducing the cathode / electrolyte interface resistance and improving the mobility of metal ions. The electrolyte comprises such a polymer binder and metal ions, preferably lithium ions. The polymer may be polyester, polyethylene, anionic polymer, polycarbonate, silicone, or, for example, three-dimensional crosslinked aliphatic polycarbonate. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] U.S. Patent No. 11848417 [Patent Document 2] Search report for European Patent Application Publication No. 4372026 [Overview of the project] [Problems that the invention aims to solve]

[0008] The object of the present invention is to overcome one or more of the above-mentioned drawbacks. The object of the present invention is to provide an ion-conductive polymer for gel polymer electrolytes (GPEs) that combines excellent ion conductivity, high thermal stability and heat resistance, and excellent resistance to high voltage (i.e., high oxidation stability).

[0009] Yet another object of the present invention is to provide an ion-conductive polymer for a gel polymer electrolyte, the electrolyte having sufficient mechanical strength to stand on its own even when a large amount of plasticizer is included in the gel polymer electrolyte (defined as being able to be handled and manipulated without damage or degradation and without the need for a support). Further, an object is to provide an ion-conductive polymer in which the amount of halogen atoms is significantly reduced and which is thus considered to be more sustainable.

[0010] Such a polymer is intended to be produced by a process that minimizes the use of harmful solvents or eliminates the need for such solvents, i.e., a more sustainable process.

[0011] Furthermore, an object is to provide a GPE comprising an ion-conductive polymer that has excellent mechanical and thermal stability and excellent ion conductivity, particularly single-ion conductivity, even at high loadings, exhibits good rate characteristics and excellent cycle stability, and has a significantly reduced amount of halogen atoms compared to state-of-the-art gel polymer electrolytes (GPEs). In particular, an object is to provide a self-standing GPE that can contain a large amount of plasticizer. Another object is to provide a simpler process for producing such a GPE, particularly a process that does not require a post-curing step to make the GPE self-standing.

[0012] In the present disclosure, when referring to or referring to an electrolyte, this electrolyte is a gel polymer electrolyte (GPE). In the present disclosure, the term "gel polymer electrolyte" is used for a polymer electrolyte containing a plasticizer.

Means for Solving the Problems

[0013] A first aspect of the present invention discloses an ion-conductive polymer for a gel polymer electrolyte (GPE) as described in the appended claims.

[0014] The ion-conductive polymer has the formula (I)

[0015] TIFF2026057507000002.tif28170

[0016] Includes a repeating unit of m according to the following, R1 is (CH2) x -R3 is where x is 1-20, and R3 is H or CN; and R2 is C1-C 10 Alkyl or C2-C 10 It is Alkenil.

[0017] Ion-conducting polymers are given by formula (II)

[0018] TIFF2026057507000003.tif56170

[0019] It further includes n repeating units according to the following: R2 and R5 are individually C1~C 10 Alkyl or C2-C 10 It is an alkenyl; and M is an alkali metal or alkaline earth metal.

[0020] In other words, an ion-conducting polymer is a copolymer containing repeating units of m according to formula (I) and repeating units of n according to formula (II).

[0021] The ratio of m to n, that is, the ratio of the number of repeating units according to equation (I) to the number of repeating units according to equation (II), is 25:1 to 1:25, preferably 20:1 to 1:20, more preferably 10:1 to 1:10, most preferably 5:1 to 1:5, for example 4:1 to 1:4, 1:2 to 2:1, for example 1.4:1.

[0022] The total number of repeating units, m+n, or q, is 50 to 5000, preferably 75 to 4500, and more preferably 100 to 4000.

[0023] A first particularly preferred example of an ion-conducting polymer is a polymer in which x is 6, R3 is CN, R2 is (CH2)2, and R5 is (CH2)2. A second particularly preferred example of an ion-conducting polymer is a polymer in which x is 10, R3 is H, R2 is (CH2)2, and R5 is (CH2)2.

[0024] Advantageously, M is Li, Na, or Mg, preferably Li.

[0025] To our surprise, the inventors discovered that when the ion-conducting polymer of the present invention is used in a gel polymer electrolyte (GPE), it functions as an ion source for alkali metals or alkaline earth metals M, particularly Li, Na, or Mg, preferably Li. As a result, the GPE of the present invention has excellent single-ion conductivity, meaning that lithium ions are primarily responsible for charge transport in the GPE of the present invention, and the occurrence of side reactions by other ion species is suppressed.

[0026] A second aspect of the present invention discloses a gel polymer electrolyte for a battery as described in the appended claims. The gel polymer electrolyte comprises, or substantially comprises, an ion-conducting polymer and a plasticizer according to the first aspect.

[0027] Advantageously, the gel polymer electrolyte contains 10 to 90% by weight, preferably 20 to 80% by weight, more preferably 25 to 75% by weight, for example 35 to 65% by weight, of the total weight of the gel polymer electrolyte as a plasticizer.

[0028] Advantageously, the gel polymer electrolyte comprises 90 to 10% by weight, preferably 80 to 20% by weight, more preferably 75 to 25% by weight, for example 65 to 35% by weight, of the total weight of the gel polymer electrolyte, an ion-conducting polymer according to the first aspect of the present invention.

[0029] Advantageously, the gel polymer electrolyte comprises, or substantially consists of, 10 to 90% by weight, preferably 20 to 80% by weight, more preferably 25 to 75% by weight, for example 35 to 65% by weight of a plasticizer, and 90 to 10% by weight, preferably 80 to 20% by weight, more preferably 75 to 25% by weight, for example 65 to 35% by weight of an ion-conducting polymer according to the first aspect of the present invention, based on the total weight of the gel polymer electrolyte.

[0030] Advantageously, the sum of the weight percentages of the ion-conducting polymer and the plasticizer in the gel polymer electrolyte is 100%, i.e., the gel polymer electrolyte is advantageously substantially composed of an ion-conducting polymer and a plasticizer according to the first aspect of the present invention. For example, the gel polymer electrolyte may consist of 40% by weight of plasticizer and 60% by weight of the ion-conducting polymer of the present invention.

[0031] The inventors have discovered that gel polymer electrolytes with a plasticizer content of 10% by weight or less, preferably 15% by weight or less, and more preferably 20% by weight or less, are brittle, have low mechanical strength, that is, are easily broken during handling, and have limited bending properties. This is thought to be due to the limited amount of plasticizer.

[0032] It is understood that the optimal amounts of plasticizer and ion-conducting polymer depend, in particular, on the composition (and structure) of the plasticizer, as well as the structure of the polymer, more specifically the ratio of m to n, the composition of the repeating units, and the total number of repeating units (and therefore the molecular weight of the polymer). Therefore, it is possible to provide gel polymer electrolytes whose properties can be modified according to the application and requirements. In other words, the advantage of the ion-conducting polymer and gel polymer electrolytes of this disclosure is that they provide a wide range of properties, and that they can be optimized according to the requirements not only by changing the relative amounts of plasticizer and polymer, but also by changing the structure of the polymer itself.

[0033] Advantageously, the ion-conducting polymer is at least partially present as a matrix in the gel polymer electrolyte, and the plasticizer is at least partially, and preferably substantially whole, dispersed in the matrix. More specifically, advantageously, the ion-conducting polymer is present as a matrix in the gel polymer electrolyte at a concentration of at least 20%, preferably at least 25%, more preferably 50%, most preferably at least 75%, for example, at least 80%, at least 90%, at least 95%, or substantially 100%.

[0034] Advantageously, the plasticizer is propylene carbonate. Advantageously, the gel polymer electrolyte comprises, or substantially comprises, 20 to 60% by weight of propylene carbonate and 80 to 40% by weight of an ion-conducting polymer according to the first embodiment, based on the total weight of the gel polymer electrolyte. Advantageously, the gel polymer electrolyte comprises a matrix of an ion-conducting polymer in which propylene carbonate is dispersed as a plasticizer.

[0035] A third aspect of the present invention relates to a battery as described in the appended claims. The battery comprises a gel polymer electrolyte according to the second aspect. Advantageously, the battery is a rechargeable battery. Advantageously, the battery is a lithium-ion battery.

[0036] A fourth aspect of the present invention discloses a method for producing an ion-conducting polymer as described in the appended claims. The ion-conducting polymer conforms to the first aspect of the present invention.

[0037] The method involves using an amino derivative according to H2N-R1, as shown in formula (III)

[0038] TIFF2026057507000004.tif19170

[0039] The process involves reacting a polymer containing repeating units of q according to the formula, where R1 is as described above, R2 is as described above, and q is 50 to 5000, preferably 75 to 4500, more preferably 100 to 4000.

[0040] The reaction is carried out in the presence of dimethylformamide (DMF).

[0041] The reaction is carried out at a temperature of 15-50°C, more preferably 15-30°C, for example, room temperature T1.

[0042] The reaction forms a first intermediate polymer. Advantageously, the first intermediate polymer does not contain ring closure, particularly an imide ring, in its molecular structure. Advantageously, the first intermediate polymer has n repeating units according to formula (III) and formula (IV)

[0043] TIFF2026057507000005.tif29170

[0044] It contains repeating units of m according to the formula, where m+n is equal to q; and the ratio of m to n is as described above.

[0045] Next, the first intermediate polymer is F3CO2SN - O2S-R4-NH2M + The reaction is as described above, and R4 and M are as described above.

[0046] The reaction is carried out in the presence of DMF.

[0047] The reaction is carried out at a temperature of 15-50°C, more preferably 15-30°C, for example, room temperature T2.

[0048] The reaction forms a second intermediate polymer. Advantageously, the second intermediate polymer does not contain ring closure, particularly an imide ring, in its molecular structure. Advantageously, the second intermediate polymer has repeating units of m according to formula (IV) and formula (V)

[0049] TIFF2026057507000006.tif56170

[0050] It contains a repeating unit of n according to the formula, where m+n is equal to q; and the ratio of m to n is as described above.

[0051] Next, the imide ring-closing of the second intermediate polymer is performed, thereby forming an ion-conducting polymer. The imide ring-closing step can be carried out by heating the second intermediate polymer to a temperature T3, which is higher than T2, and then raising the temperature from T3 to T4 (i.e., further heating). Alternatively, the imide ring-closing step can be carried out at T2 in the presence of a catalyst. In other words, if a catalyst is used for imide ring-closing, it is not necessary to heat the second intermediate polymer.

[0052] Advantageously, the temperature T3 is 30 to 80°C, preferably 35 to 70°C, more preferably 40 to 60°C, for example 50°C.

[0053] Advantageously, the temperature T4 is 100 to 250°C, preferably 125 to 200°C, and more preferably 150 to 180°C.

[0054] Advantageously, when heating the second intermediate polymer to close the imide ring, this is done in the presence of DMF.

[0055] Advantageously, when the imide ring is closed in the presence of a catalyst, the catalyst contains or substantially consists of carbonyldiimidazole.

[0056] This disclosure further relates to the use of an ion-conducting polymer according to the first embodiment in a mixture for producing a gel polymer electrolyte according to the second embodiment.

[0057] The embodiments of the invention will be described in more detail below with reference to the attached drawings. The same reference numerals indicate the same features. [Brief explanation of the drawing]

[0058] [Figure 1] This figure shows the H-NMR spectrum of the second ion-conducting polymer of the present invention. [Figure 2] This figure shows the FTIR spectrum of the second polymer. [Figure 3] This figure shows the TGA analysis of the second polymer. [Figure 4]Figure showing the DSC analysis of the second polymer. [Figure 5] Figure showing the LSV analysis of the second polymer. [Figure 6] Figure showing the thermal stability (heat resistance) of the six gel polymer electrolytes of the present invention measured by TGA. [Figure 7] Figure showing the thermal stability (heat resistance) of the six gel polymer electrolytes of the present invention measured by TGA. [Figure 8] Figure showing the glass transition temperature of the six gel polymer electrolytes of the present invention measured by DSC. [Figure 9] Figure showing the glass transition temperature of the six gel polymer electrolytes of the present invention measured by DSC. [Figure 10] Figure showing the ionic conductivity of the four gel polymer electrolytes of the present invention. [Figure 11] Figure showing the ionic conductivity of the four gel polymer electrolytes of the present invention.

MODE FOR CARRYING OUT THE INVENTION

[0059] The ion-conductive polymer is a copolymer and includes repeating units of m according to formula (I) and repeating units of n according to formula (II),

[0060] TIFF2026057507000007.tif29170

[0061] and

[0062] TIFF2026057507000008.tif56170

[0063] R1 is (CH2) x -R3, x is 1 to 20, preferably 2 to 15, more preferably 4 to 10, and R3 is H or CN; R2 and R5 are each independently C1-C 10 alkyl or C2-C 10 alkenyl; and M is an alkali metal or alkaline earth metal.

[0064] Advantageously, m and n are selected such that the total number of repeating units q equal to m+n is 50 to 5000, preferably 75 to 4500, and more preferably 100 to 4000.

[0065] Advantageously, m is 5 to 4500, preferably 10 to 3600. Advantageously, n is 5 to 4500, preferably 10 to 3600.

[0066] Advantageously, the ion-conducting polymer of the present invention has a molecular weight of 10 to 3000 kDa, preferably 11 to 2500 kDa, more preferably 12 to 2000 kDa, and most preferably 13 to 1800 kDa.

[0067] It is understood that the values ​​of m and n, i.e., the number of repeating units according to equations (I) and (II), depend on the total number of repeating units q and the ratio of m to n, i.e., the ratio of the number of repeating units according to equation (I) to the number of repeating units according to equation (II). For example, if q is 3000 and m:n is 2:1, the copolymer contains 2000 repeating units according to equation (I) and 1000 repeating units according to equation (II). If q is 5000 and m:n is 1:1, the copolymer contains 2500 repeating units according to equation (I) and 2500 repeating units according to equation (II).

[0068] While repeating units according to formula (II) determine the ionic conductivity of the polymer, repeating units according to formula (I) are involved in the matrix formation properties, i.e., the properties of the gel polymer electrolyte containing a plasticizer in the present invention. It is understood that the ionic conductivity of an ionic conductive polymer can be changed by changing the ratio of m to n with respect to a certain total number of repeating units q. This makes it possible to obtain a highly versatile ionic conductive polymer and to fine-tune its properties in accordance with other components in the gel polymer electrolyte, particularly the plasticizer.

[0069] R1 can be a straight chain or branched, i.e., (CH2) x The chain can be straight or branched. Favorably, R1, i.e., (CH2) x The chain is a straight chain.

[0070] R2 can be a straight chain or branched. Advantageously, R2 is (CH2) y C1~C according to 10 It is an alkyl group, where y is 1 to 10, preferably 1 to 4, more preferably 1 or 2, i.e., CH2 or (CH2)2.

[0071] R5 can be a straight chain or branched. Advantageously, R2 is (CH2) w C1~C according to 10 It is an alkyl group, where w is 1 to 10, preferably 1 to 4, more preferably 1 or 2, i.e., CH2 or (CH2)2.

[0072] Advantageously, the copolymer is a random copolymer, i.e., a copolymer in which repeating units according to formulas (I) and (II) are randomly distributed. Alternatively, and more advantageously, the copolymer is a block copolymer, i.e., a copolymer comprising one or more "blocks" of repeating units according to formula (I) and one or more "blocks" of repeating units according to formula (II). An example of such a copolymer is formula (VI)

[0073] TIFF2026057507000009.tif65170

[0074] The structure is represented as shown, and the copolymer contains one block of n repeating units according to formula (II) and one block of m repeating units according to formula (I).

[0075] An example of an ion-conducting polymer is a block copolymer where x is 6, R3 is CN, R2 is (CH2)2, and R5 is (CH2)2, and in particular M is Li.

[0076] TIFF2026057507000010.tif67170

[0077] That is the case.

[0078] A second example of an ion-conducting polymer is a block copolymer where x is 10, R3 is H, R2 is (CH2)2, and R5 is (CH2)2, and in particular M is Li.

[0079] TIFF2026057507000011.tif71170

[0080] That is the case.

[0081] When x is 6, R3 is CN, and R2 is (CH2)2, the first and second intermediate polymers are favorably derived from formulas (VII) and (VIII), respectively.

[0082] TIFF2026057507000012.tif47170

[0083] and

[0084] TIFF2026057507000013.tif56170

[0085] It has a structure that conforms to [the following].

[0086] For example, if x is 10, R3 is H, and R2 is (CH2)2, the first and second intermediate polymers are favorably given by formulas (IX) and (X), respectively.

[0087] TIFF2026057507000014.tif47170

[0088] and

[0089] TIFF2026057507000015.tif56170

[0090] It has a structure that conforms to [the following].

[0091] Advantageously, the ion-conducting polymer of the present invention exhibits high heat resistance, meaning it can withstand temperatures of at least 250°C, preferably at least 300°C, and more preferably at least 350°C, as measured by thermogravimetric analysis (TGA) under an argon flow rate of 60 mL / min and a heating rate of 10°C / min. Surprisingly, the inventors found that the heat resistance of the ion-conducting polymer does not change significantly even when the m-to-n ratio of the polymer changes.

[0092] The glass transition temperature of an ion-conducting polymer is understood to be determined by the number of repeating units in equations (I) and (II), more specifically by the ratio of m to n of the repeating units. Advantageously, the glass transition temperature of the polymer of the present invention is 30 to 175°C, preferably 50 to 150°C, more preferably 80 to 120°C, for example 90 to 110°C, which is measured by performing two cycles of heating scans at 10°C / min from -80°C to over 200°C in an argon atmosphere using differential scanning calorimetry (DSC), and a reliable and reproducible glass transition temperature value is ensured by adopting the results of the second cycle so that the thermal history of the polymer is reliably erased. It is understood that the precise glass transition temperature of an ion-conducting polymer depends on the ratio of m to n.

[0093] Advantageously, the ion-conducting polymer exhibits a linear sweep voltammetry (LSV) analysis of 1 mV s in propylene carbonate at room temperature. -1 When measured, it exhibits high oxidation stability of at least 2.5V, preferably at least 3V, more preferably at least 4V, for example, at least 4.5V.

[0094] The gel polymer electrolyte according to the present invention comprises, or substantially comprises, the ion-conducting polymer and plasticizer of the present invention.

[0095] The plasticizer may be any organic solvent well known in the art. Non-limiting examples of suitable plasticizers include linear carbonates, cyclic carbonates, ethers, and nitriles. Preferred plasticizers for use with the ion-conducting polymer of the present invention include propylene carbonate and ethylene carbonate, with propylene carbonate being preferred.

[0096] The gel polymer electrolyte according to the present invention can be manufactured by methods well known in the art. A preferred method includes preparing a mixture comprising an ion-conducting polymer, a plasticizer, and a solvent; solvent casting of the mixture; subsequent evaporation of the solvent used in preparing the mixture; and optionally drying. Another exemplary method is a so-called drying method, which includes mixing the ion-conducting polymer and the plasticizer; subsequently extruding the mixture; and optionally calendering or laminating it. Advantageously, the manufacturing process of the gel polymer electrolyte according to the present invention does not require a curing step as a final step to make the electrolyte self-sufficient.

[0097] The inventors have surprisingly discovered that the gel polymer electrolyte of this disclosure exhibits a lithium ion transport number (LTN) close to 1 when M in the repeating units according to formula (II) of the ion-conducting polymer is lithium. That is, lithium ions are primarily responsible for charge transport in the gel polymer electrolyte of the present invention, and the occurrence of side reactions by other ion species is suppressed. In other words, the gel polymer electrolyte has excellent single-ion conductivity. To put it another way, the gel polymer electrolyte of the present invention improves both the efficiency and cycle stability of battery cells containing the gel polymer electrolyte because it enables uniform deposition of lithium and reduces system polarization. While not intended to be constrained by theory, the inventors believe this is due to the ion-conducting polymer containing Li (where M is Li in formula (II)). The same was observed when M was other alkali metals or alkaline earth metals such as Na or Mg, with the effect being most pronounced in the case of Li.

[0098] Advantageously, the gel polymer electrolyte of the present invention has good heat resistance, meaning it can withstand temperatures of at least 100°C, preferably at least 120°C, and more preferably at least 130°C, as measured at 10°C / min under an argon flow rate of 60 mL / min in a TGA. Advantageously, the heat resistance depends on the properties (i.e., its chemical structure) of the plasticizer in the electrolyte. Therefore, the plasticizer used in the gel polymer electrolyte can be changed depending on the required heat resistance.

[0099] Plasticizers are used to reduce the brittleness of polymer materials, which is achieved by lowering the glass transition temperature. Therefore, it is understood that the glass transition temperature of gel polymer electrolytes depends on the amount of plasticizer. Advantageously, the glass transition temperature of gel polymer electrolytes lies between an immeasurable value (large amount of plasticizer) and the glass transition temperature of ion-conducting polymers (no plasticizer).

[0100] Furthermore, the ionic conductivity of gel polymer electrolytes is higher than that of ionic conductive polymers, and this effect is understood to be due to the increased flexibility of the gel polymer electrolyte in the presence of plasticizers. In other words, the ionic conductivity of gel polymer electrolytes increases with increasing amounts of plasticizers.

[0101] Advantageously, the ionic conductivity of the gel polymer electrolyte is 10 at room temperature (25°C). -6 S / cm or more, preferably 5 × 10 -6 S / cm or more, for example, 10 -5 S / cm or larger, or 5×10 -5 It is S / cm or higher.

[0102] Advantageously, the ionic conductivity of the gel polymer electrolyte is 10 at 70°C. -5 S / cm or more, preferably 2 × 10 -5 S / cm or more, for example, 5 x 10 -5 S / cm or more, or 10 -4 It is S / cm or higher. [Examples]

[0103] H2N-(CH2)9-CH3 as an amino derivative was subjected to q repeating units in the presence of DMF at room temperature for 2 hours.

[0104] TIFF2026057507000016.tif23170

[0105] The polymer containing was reacted with F3CO2SN for 2 hours at room temperature in the presence of DMF. - O2S(CH2)2NH2Li + The reaction was carried out. Next, the resulting reaction product was first heated at 50°C for 4 hours in the presence of DMF, and then further heated at 170°C for 16 hours in the presence of DMF.

[0106] The m-to-n ratio of the obtained ion-conducting polymer was 1.4:1. A second polymer was prepared similarly, and its m-to-n ratio was 1:2.85.

[0107] Figures 1 and 2 show the H-NMR and FTIR spectra of the obtained ion-conducting polymers with a m-to-n ratio of 1.4:1, respectively.

[0108] Figure 3 shows the TGA analysis of a polymer with an m-to-n ratio of 1.4:1, demonstrating high heat resistance exceeding 300°C. Figure 4 shows the DSC analysis of a polymer with an m-to-n ratio of 1.4:1, indicating a glass transition temperature of 91°C. Figure 5 shows the LSV analysis of a polymer with an m-to-n ratio of 1.4:1, demonstrating high oxidation stability of at least 5V. [Examples]

[0109] Using the two ion-conducting polymers from Example 1 (m / n ratios of 1.4:1 and 1:2.85), each polymer was mixed with propylene carbonate as a plasticizer in a solvent, cast onto a Teflon® substrate, the solvent was evaporated, and the resulting gel polymer electrolyte was dried to produce a gel polymer electrolyte. Three different amounts of propylene carbonate were used: 20% by weight (80% by weight of polymer), 40% by weight (60% by weight of polymer), and 60% by weight (40% by weight of polymer).

[0110] In all ion-conducting polymers, gel polymer electrolytes containing 20% ​​by weight of propylene carbonate were brittle, while gel polymer electrolytes containing 60% by weight of propylene carbonate were very viscous and even tended to flow. Gel polymer electrolytes containing 40% by weight of propylene carbonate were also viscous, but gel polymer electrolytes containing polymers with a m / n ratio of 1:2.85 were particularly manageable.

[0111] The thermal stability of all six gel polymer electrolytes (three with different plasticizer / polymer ratios and two with different polymer m / n ratios) was investigated by TGA. Figures 6 and 7 show the results for electrolytes containing polymers with m / n ratios of 1.4:1 and 1:2.85, respectively, as a function of weight percent of propylene carbonate ("PC"). The polymer TGA profiles (mass loss against temperature) are also shown as references ("copolymer"). The temperature of thermal stability is defined as the temperature at which a 5% mass loss of the gel polymer electrolyte is measured. All six electrolytes are stable at a temperature of at least 130°C. While thermal stability was found to decrease with increasing amounts of propylene carbonate, the effect of the m / n ratio of the ion-conducting polymer was found to be limited.

[0112] Glass transition temperatures (T) of the same six gel polymer electrolytes g) was also measured by DSC. Figures 8 and 9 show the results for electrolytes containing polymers with m / n ratios of 1.4:1 and 1:2.85, respectively, as a function of weight % of propylene carbonate ("PC"). The DSC profile of the polymer is also shown as reference ("copolymer"). The T of the electrolyte is higher compared to the case of polymer alone ("copolymer") because the plasticizer (propylene carbonate) plasticizes the system. g The amount of propylene carbonate decreases, and therefore T increases with the increase in propylene carbonate. g The value decreases. In an electrolyte containing 60% by weight of propylene carbonate, T g It was not possible to measure. In electrolytes containing polymers with an m / n ratio of 1.4:1, the T of the polymer alone was not measured. g The temperature was 91°C for the first electrolyte, and 42°C and 6°C for electrolytes containing 20% ​​and 40% by weight of propylene carbonate, respectively. For electrolytes containing polymers with an m / n ratio of 1:2.85, the temperature of the polymer alone was 91°C. g The temperature was 135°C for the electrolyte containing 20% ​​and 40% by weight of propylene carbonate, respectively, and 52°C and 27°C for the electrolyte containing 40% and 40% by weight of propylene carbonate. In other words, polymers with a relatively large number of repeating units according to formula (II) have a temperature of T g This has a positive effect. This is thought to be because the repeating units of formula (I) contribute to the flexibility of the polymer, while the repeating units of formula (II) do not contribute much to flexibility.

[0113] The ionic conductivity of the four gel polymer electrolytes was also measured at temperatures of 25–70°C. The electrolytes tested contained 40% and 60% by weight propylene carbonate, with polymer m / n ratios of 1.4:1 and 1:2.85. Figures 10 and 11 show the results for electrolytes containing polymers with m / n ratios of 1.4:1 and 1:2.85, respectively, as a function of wt% propylene carbonate ("PC"). The gel polymer electrolyte containing 40% by weight propylene carbonate exhibited a conductivity of 5 × 10⁻¹⁶ at 25°C. -6 Less than S / cm, and 5 × 10 at 70°C -5 While the ionic conductivity was relatively low at less than S / cm, the gel polymer electrolyte containing 60% by weight of propylene carbonate showed a conductivity of 5 × 10⁻⁶ at 25°C.-5 S / cm or more, and 10 -4 It can reach about S / cm, and at 70℃ it is 5×10 -4 It exhibited excellent ionic conductivity exceeding S / cm.

Claims

1. Repeating units of m according to equation (I), and repeating units of n according to equation (II), and An ion-conducting polymer for gel polymer electrolytes, R １ (CH ２ ) ｘ -R ３ And x is 1 to 20, and R ３ is H or CN; R ２ and R ５ are each independently C １ ~C １０ alkyl or C ２ ~C １０ alkenyl; M is an alkali metal or alkaline earth metal; The ratio of m to n (m / n) is 25:1 to 1:25; and m + n is q, and q is between 50 and 5000. Ion-conducting polymer.

2. x is 6, R ３ CN, R ２ (CH ２ ) ２ , and R ５ (CH ２ ) ２ The ion-conducting polymer according to claim 1.

3. x is 10, R ３ H and R ２ (CH ２ ) ２ , and R ５ (CH ２ ) ２ The ion-conducting polymer according to claim 1.

4. The ion-conducting polymer according to claim 1, wherein M is Li, Na, or Mg, preferably Li.

5. The ion-conducting polymer according to claim 1, wherein the m / n ratio is 10:1 to 1:10, preferably 5:1 to 1:

5.

6. A gel polymer electrolyte comprising the ion-conducting polymer and plasticizer described in claim 1.

7. The gel polymer electrolyte according to claim 6, wherein the ion-conducting polymer is at least partially present as a matrix, and the plasticizer is dispersed in the matrix.

8. The gel polymer electrolyte according to claim 6, comprising 10 to 80% by weight of the plasticizer and 90 to 20% by weight of the ion-conducting polymer based on the total weight of the gel polymer electrolyte.

9. The gel polymer electrolyte according to claim 6, wherein the plasticizer comprises propylene carbonate.

10. The gel polymer electrolyte according to claim 9, comprising 20 to 60% by weight of propylene carbonate and 80 to 40% by weight of the ion-conducting polymer based on the total weight of the gel polymer electrolyte.

11. A battery comprising the gel polymer electrolyte described in claim 6, preferably a lithium-ion secondary battery.

12. A method for producing an ion-conducting polymer according to claim 1, - H ２ N-R １ The amino derivatives according to formula (III) A step of reacting with a polymer containing repeating units of q according to the formula, R １ (CH ２ ) ｘ -R ３ And x is 1 to 20, and R ３ is H or CN, R ２ is C １ ~C １０ Alkyl or C ２ ~C １０ The step is an alkenyl, and q is between 50 and 5000. - Temperature T of 15–80°C in the presence of dimethylformamide (DMF) １ The first intermediate polymer is formed by performing the following steps: - The first intermediate polymer is subjected to a temperature T of 15 to 50°C in the presence of DMF. ２ So, F ３ CO ２ SN － O ２ S-R ５ -NH ２ M ＋ It will react with R ５ is C １ ~C １０ Alkyl or C ２ ~C １０ The step of forming a second intermediate polymer, wherein M is an alkenyl and M is an alkali metal or alkaline earth metal, - A step of closing the imide ring of the second intermediate polymer, thereby forming the ion-conducting polymer, The ring closure of the imide ring is performed by the second intermediate polymer in the presence of DMF at a temperature of 30 to 80°C T ３ Heat to T ３ Temperature T from 100 to 250°C ４ This is done by doing so, or in the presence of a catalyst, T ２ Steps to be performed A method that includes this.

13. The first intermediate polymer comprises n repeating units according to formula (III) and formula (IV) Includes a repeating unit of m according to the following, m + n is equal to q; and The ratio of m to n is between 25:1 and 1:

25. The method according to claim 12.

14. The second intermediate polymer is a repeating unit of m according to formula (IV), and formula (V) Includes the following n repeating units, m + n is equal to q; and The ratio of m to n is between 25:1 and 1:

25. The method according to claim 13.

15. The method according to claim 12, wherein M is Li, Na, or Mg.

16. The aforementioned imide ring, in the presence of a catalyst, T ２ The method according to claim 12, wherein the ring is closed by and the catalyst comprises carbonyldiimidazole.

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