Polymer solid electrolyte and all-solid-state battery comprising same

Abstract

The present invention relates to a polymer solid electrolyte, which can simultaneously implement excellent ionic conductivity and electrochemical stability, and an all-solid-state battery comprising same.

Description

Polymer solid electrolyte and all-solid-state battery containing the same

[0001] The present invention relates to a solid electrolyte comprising a zwitterionic polymer and an all-solid-state battery employing the same.

[0002] Recently, as the development of lithium batteries with improved energy density and safety has become a necessity, all-solid-state batteries that use solid electrolytes instead of liquid electrolytes are attracting attention as next-generation batteries.

[0003] Solid electrolytes can be classified into polymer solid electrolytes or inorganic solid electrolytes depending on their material composition. Inorganic solid electrolytes, in particular, have been widely applied due to their ability to achieve high ionic conductivity. However, inorganic solid electrolytes suffer from chemical instability, high interfacial resistance with electrodes, and the high temperature / high pressure required during cell manufacturing and operation, limiting their commercialization.

[0004] On the other hand, polymer solid electrolytes offer advantages over inorganic solid electrolytes in terms of flexibility, lightness, and processability. However, polymer solid electrolytes suffer from lower ionic conductivity and lithium ion yield compared to conventional liquid and inorganic solid electrolytes. Furthermore, their low electrochemical window hinders their combination with high-voltage cathode materials.

[0005] To solve this problem, research is being conducted on applying ionic polymer materials such as cationic polymers and anionic polymers, but ionic conductivity is still not sufficient, and even if ionic conductivity is improved somewhat, there is a limitation in that compatibility with high-capacity cathode materials is low.

[0006] [Prior Art Literature]

[0007] [Non-patent literature]

[0008] (Non-patent literature 1) J. Mater. Chem., 2001, 11, 1057-1062.

[0009] One aspect of the present invention aims to provide a polymer solid electrolyte capable of simultaneously achieving excellent ionic conductivity and electrochemical stability, and a method for producing the same.

[0010] One aspect of the present invention provides a polymer solid electrolyte comprising a zwitterionic polymer and a metal salt, the zwitterionic polymer including a structural unit derived from a zwitterionic compound represented by the following chemical formula 1.

[0011] [Chemical Formula 1]

[0012]

[0013] (R1 is hydrogen or methyl;

[0014] p is an integer from 1 to 20, preferably an integer from 3 to 15, more preferably an integer from 5 to 13, most preferably 6 or 11;

[0015] q is an integer from 1 to 20, preferably an integer from 1 to 10, more preferably an integer from 1 to 6, most preferably 2 or 3;

[0016] X + Is , or and;

[0017] R2 to R5 are each independently hydrogen or (C1-C7)alkyl, or R2 and R3, and R4 and R5 may be connected to each other to form an alicyclic ring or an aromatic ring;

[0018] Y - Is , or and;

[0019] R6 is fluoro or fluoro(C1-C7)alkyl.)

[0020] The above zwitterionic compound can be represented by the following chemical formula 2 or 3.

[0021] [Chemical Formula 2]

[0022]

[0023] [Chemical Formula 3]

[0024]

[0025] (In the above chemical formulas 2 and 3,

[0026] R 11 is fluoro or fluoro(C1-C7)alkyl;

[0027] R1, X + , p and q are the same as defined in the above chemical formula 1.)

[0028] In the above chemical formulas 1 to 3, p may be an integer from 10 to 20, and q may be an integer from 1 to 7.

[0029] The above zwitterionic compound can be represented by the following chemical formulas 4 to 6.

[0030] [Chemical Formula 4]

[0031]

[0032] [Chemical Formula 5]

[0033]

[0034] [Chemical Formula 6]

[0035]

[0036] (In the above chemical formulas 4 to 6,

[0037] R1 is hydrogen or methyl;

[0038] n is an integer from 1 to 7;

[0039] X + Is , , or and;

[0040] R6 and R7 are each independently hydrogen or (C1-C7)alkyl.

[0041] The above zwitterionic polymer and metal salt may be included in a weight ratio of 1:0.05 to 1.5.

[0042] The above metal salt may be a lithium salt.

[0043] Another aspect of the present invention provides a method for producing a polymer solid electrolyte, comprising the steps of: preparing a solid electrolyte slurry composition by mixing a zwitterionic compound represented by the following chemical formula 1, a metal salt, and an organic solvent; and applying the solid electrolyte slurry composition to a substrate and thermally polymerizing the zwitterionic compound.

[0044] [Chemical Formula 1]

[0045]

[0046] (In the above chemical formula 1,

[0047] R1, X + , Y - , p and q are the same as defined in the above chemical formula 1.)

[0048] The above solid electrolyte slurry composition may contain a zwitterionic compound and a metal salt in a molar ratio of 1:0.1 to 2.

[0049] The above solid electrolyte slurry composition may contain 5 to 30 parts by weight of an organic solvent per 100 parts by weight of a zwitterionic compound.

[0050] The above polymerization may be a thermal polymerization performed under conditions of 110 to 150°C.

[0051] Another aspect of the present invention provides an all-solid-state battery comprising the polymer solid electrolyte.

[0052] The above-described all-solid-state secondary battery according to one embodiment includes a positive electrode layer, a solid electrolyte layer, and a negative electrode layer, and the solid electrolyte layer may include the above-described polymer solid electrolyte according to one embodiment.

[0053] The above-mentioned positive electrode layer is impregnated with the above-mentioned polymer solid electrolyte according to one embodiment, and the above-mentioned positive electrode layer and the solid electrolyte layer may be integrated with each other.

[0054] The thickness of the solid electrolyte layer may be 30 to 100 μm.

[0055] The above negative electrode layer includes a negative electrode current collector and a negative electrode active material layer, and the negative electrode active material layer may be lithium metal.

[0056] An all-solid-state battery employing a polymer solid electrolyte according to one aspect of the present invention can simultaneously satisfy excellent battery performance and life characteristics.

[0057] Specifically, the polymer solid electrolyte according to one embodiment exhibits high ionic conductivity capable of operating at room temperature, excellent interfacial compatibility with electrodes, and superior mechanical strength. Furthermore, the polymer solid electrolyte according to one embodiment exhibits high oxidation stability, excellent compatibility with high-capacity cathode materials such as NCM811, and excellent interfacial stability with lithium metal anodes. Furthermore, its superior processability may facilitate commercialization.

[0058] Figure 1 illustrates the results of analysis of the life characteristics of the all-solid-state lithium metal batteries of Example 1 and Comparative Example 1.

[0059] Figure 2 illustrates the results of analysis of the life characteristics of the all-solid-state lithium metal batteries of Example 3 and Comparative Example 2.

[0060] Figure 3 illustrates the results of analysis of the life characteristics of the all-solid-state lithium metal batteries of Example 4 and Comparative Example 3.

[0061] Unless otherwise defined herein, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0062] As used herein, the singular forms may be intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0063] Additionally, the numerical ranges used herein include lower and upper limits and all values ​​within that range, increments logically derived from the shape and width of the defined range, all doubly defined values, and all possible combinations of upper and lower limits of numerical ranges defined in different shapes. Unless otherwise specified herein, values ​​outside the defined numerical range that may arise due to experimental error or rounding of values ​​are also included in the defined numerical range.

[0064] The term "comprises" in this specification is an open-ended description equivalent to expressions such as "includes," "contains," "has," or "characterized by," and does not exclude additional elements, materials, or processes not listed herein.

[0065] The term "alkyl" as used herein refers to an organic radical derived from an aliphatic hydrocarbon by the removal of a single hydrogen, and may include both straight-chain and branched forms. Examples of alkyl include, but are not limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, hexyl, and ethylhexyl.

[0066] The term "fluoroalkyl" as used herein means that at least one hydrogen atom in the alkyl is replaced with a fluoro group (-F).

[0067] One aspect of the present invention provides a polymer solid electrolyte capable of achieving excellent ionic conductivity and electrochemical stability.

[0068] Specifically, the polymer solid electrolyte according to one aspect may include a zwitterionic polymer and a metal salt including a structural unit derived from a zwitterionic compound represented by the following chemical formula 1.

[0069] [Chemical Formula 1]

[0070]

[0071] (R1 is hydrogen or methyl;

[0072] p is an integer from 1 to 20, preferably an integer from 3 to 15, more preferably an integer from 5 to 13, most preferably 6 or 11;

[0073] q is an integer from 1 to 20, preferably an integer from 1 to 10, more preferably an integer from 1 to 6, most preferably 2 or 3;

[0074] X + Is , or and;

[0075] R2 to R5 are each independently hydrogen or (C1-C7)alkyl, or R2 and R3, and R4 and R5 may be connected to each other to form an alicyclic ring or an aromatic ring;

[0076] Y - Is , or and;

[0077] R6 is fluoro or fluoro(C1-C7)alkyl.)

[0078] That is, the polymer solid electrolyte according to one embodiment may include a zwitterionic polymer matrix manufactured using a zwitterionic compound represented by the above chemical formula 1 as a monomer, and a metal salt uniformly distributed in the polymer matrix. For example, the zwitterionic polymer and the metal salt may be included in a weight ratio of 1:0.05 to 1.5, or a weight ratio of 1:0.1 to 1.5, or a weight ratio of 1:0.5 to 1.5, or a weight ratio of 1:1 to 1.5.

[0079] A polymer solid electrolyte according to one aspect can simultaneously realize excellent ion dissociation, mobility, and stability by including a zwitterionic polymer and a metal salt prepared from a zwitterionic compound satisfying the structural characteristics described above.

[0080] For example, when the compound represented by the above chemical formula 1 has only a cationic group or an anionic group, there is a problem that the ionic conductivity and lithium ion yield of the polymer solid electrolyte manufactured therefrom are significantly reduced. In addition, when the compound represented by the above chemical formula 1 has a short-chain alkylene group in which p is 6 or less, the mechanical strength and stability of the polymer solid electrolyte may be significantly reduced, making it difficult to achieve the effects intended by the present invention.

[0081] Specifically, the zwitterionic compound represented by the above chemical formula 1 may be represented by the following chemical formula 2 or 3.

[0082] [Chemical Formula 2]

[0083]

[0084] [Chemical Formula 3]

[0085]

[0086] (In the above chemical formulas 2 and 3,

[0087] R 11 is fluoro or fluoro(C1-C7)alkyl;

[0088] R1, X + , p and q are the same as defined in the above chemical formula 1.)

[0089] For example, the above p may be an integer from 10 to 20, and q may be an integer from 1 to 7. When the above ranges are satisfied, the mechanical properties of the polymer solid electrolyte may be further improved.

[0090] For example, the above X + may be selected from the following structural formulas.

[0091]

[0092] (In the above structural formula, R6 to R9 are each independently hydrogen or (C1-C7) alkyl.)

[0093] For example, the above R 11 It can be fluoro or perfluoro(C1-C7)alkyl.

[0094] More specifically, the zwitterionic compound can be represented by the following chemical formulas 4 to 6.

[0095] [Chemical Formula 4]

[0096]

[0097] [Chemical Formula 5]

[0098]

[0099] [Chemical Formula 6]

[0100]

[0101] (In the above chemical formulas 4 to 6,

[0102] R1 is hydrogen or methyl;

[0103] n is an integer from 1 to 7;

[0104] X + Is , , or and;

[0105] R6 and R7 are each independently hydrogen or (C1-C7)alkyl.

[0106] The above zwitterionic compound may be, for example, selected from the following structures, but is not necessarily limited thereto.

[0107]

[0108] The metal salt may be a lithium salt, and the lithium salt may be, for example, one or more selected from lithium chloride (LiCl), lithium bromide (LiBr), lithium tetrafluoroborate (LiBF4), lithium hexafluorophosphate (LiPF6), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and lithium bis(pentafluoroethanesulfonyl)imide (LiBETI). More specifically, lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and lithium bis(pentafluoroethanesulfonyl)imide (LiBETI) may be used, but is not necessarily limited thereto.

[0109] In addition, one aspect of the present invention provides a method for producing the above-described polymer solid electrolyte.

[0110] Specifically, a method for producing a polymer solid electrolyte according to one embodiment is characterized by including: (a) a step of mixing a zwitterionic compound represented by the following chemical formula 1, a metal salt, and an organic solvent to produce a solid electrolyte slurry composition; and (b) a step of applying the solid electrolyte slurry composition to a substrate and polymerizing the zwitterionic compound.

[0111] [Chemical Formula 1]

[0112]

[0113] (In the above chemical formula 1,

[0114] R1, X + , Y - , p and q are the same as defined in the above chemical formula 1.)

[0115] The method for manufacturing a polymer solid electrolyte according to one aspect can make the distribution of the metal salt included in the polymer solid electrolyte very even by satisfying the above steps, and can further improve the ionic conductivity of the polymer solid electrolyte and the interfacial compatibility with the electrode.

[0116] For example, when a solid electrolyte is manufactured by first polymerizing the zwitterionic compound and then introducing a metal salt, it may be difficult to evenly distribute the metal salt, and the ionic conductivity of the solid electrolyte and the interfacial compatibility with the electrode may deteriorate.

[0117] The above solid electrolyte slurry composition may include a zwitterionic compound and a metal salt in a molar ratio of 1:0.1 to 0.5, or a molar ratio of 1:0.1 to 3, or a molar ratio of 1:0.5 to 2.

[0118] The above solid electrolyte slurry composition may contain 5 to 30 parts by weight, or 5 to 20 parts by weight, or 10 to 20 parts by weight of an organic solvent with respect to 100 parts by weight of a zwitterionic compound.

[0119] The above solid electrolyte slurry composition is a curable composition, and a solid electrolyte can be manufactured through a curing (polymerization) reaction. The curing reaction may be performed by photocuring, thermal curing, or a combination thereof, and may be performed by appropriate modifications depending on the purpose.

[0120] In the above solid electrolyte slurry composition, the organic solvent can be used without limitation as long as it can dissolve the zwitterionic compound, and for example, it can be an alcohol-based organic solvent selected from methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butanol, and 2-ethylhexyl alcohol, and specifically, ethanol can be used, but is not limited thereto.

[0121] The above solid electrolyte slurry composition may further include an initiator, and may further include a photoinitiator or a thermal initiator depending on the curing method. The initiator may be any known initiator without limitation, and examples of the photoinitiator may be selected from, but are not limited to, acetophenone compounds, benzophenone compounds, triazine compounds, benzoin compounds, imidazole compounds, xanthone compounds, phosphine compounds, and oxime compounds. Examples of the thermal initiator may be selected from, but are not limited to, benzoyl peroxide (BPO), dicumyl peroxide (DCP), azobisisobutyronitrile (AIBN), and the like.

[0122] Specifically, the polymerization in step (b) may be thermal polymerization, and the thermal polymerization may be performed at a temperature in the range of 50 to 300°C, or 50 to 200°C, or 100 to 200°C, or 110 to 150°C using a heating device such as an oven.

[0123] In addition, one aspect of the present invention provides an all-solid-state battery including the polymer solid electrolyte.

[0124] Hereinafter, an all-solid-state battery according to one embodiment will be described. However, it is to be understood that, except for including the polymer solid electrolyte according to one embodiment, the battery can be manufactured in a structure known in the art using a manufacturing method and materials common in the art.

[0125] An all-solid-state battery according to one embodiment includes a positive electrode layer and a negative electrode layer, and includes a solid electrolyte layer between the positive electrode layer and the negative electrode layer, and the solid electrolyte layer may include a polymer solid electrolyte according to one embodiment.

[0126] The above-mentioned positive electrode layer may include a positive electrode collector and a positive electrode active material layer formed on the positive electrode collector. Specifically, the positive electrode active material layer may be impregnated with a polymer solid electrolyte according to one aspect within pores, and the positive electrode layer and the solid electrolyte layer may be integrated with each other.

[0127] For example, the thickness of the solid electrolyte layer may be 10 to 100 ㎛, or 30 to 100 ㎛, or 30 to 80 ㎛, wherein the thickness of the solid electrolyte layer means the thickness of a section where the positive electrode active material layer and the solid electrolyte are not mixed and only the polymer solid electrolyte according to one embodiment exists.

[0128] An all-solid-state battery according to one embodiment may be manufactured by including the steps of (S1) applying a cathode material slurry composition to one surface of a cathode current collector, drying and rolling to manufacture a cathode active material layer having pores; (S2) impregnating the cathode active material layer with a solid electrolyte slurry composition according to one embodiment and thermally polymerizing the same to manufacture a cathode layer impregnated with a polymer solid electrolyte and a solid electrolyte layer integrated with the cathode layer; and (S3) laminating the cathode layer impregnated with the polymer solid electrolyte and the anode layer.

[0129] Non-limiting examples of the positive electrode current collector may include a foil made of aluminum, nickel, or a combination thereof, and the positive electrode material slurry may include a solvent, a binder, a conductive agent, a dispersant, etc., in addition to the positive electrode active material, if necessary.

[0130] The above cathode active material may be a conventional cathode active material used in this technical field, and non-limiting examples thereof include lithium cobalt oxide composite oxide (LiCoO2), spinel crystal type lithium manganate composite oxide (LiMn2O4), lithium manganate composite oxide (LiMnO2), lithium nickelate composite oxide (LiNiO2), lithium iron phosphate (LiFePO4), lithium manganese phosphate (LiMnPO4), lithium cobalt phosphate (LiCoPO4), lithium iron pyrophosphate (Li2FeP2O7), lithium niobate composite oxide (LiNbO2), lithium ironate composite oxide (LiFeO2), lithium magnesiumate composite oxide (LiMgO2), lithium cuprate composite oxide (LiCuO2), lithium zincate composite oxide (LiZnO2), lithium molybdate composite oxide (LiMoO2), and tantalum acid. Lithium composite oxide (LiTaO2), lithium tungstate composite oxide (LiWO2), lithium permanganate nickel cobalt composite oxide (xLi2MnO3(1-x)LiMn1-y-zNiyCozO2), lithium nickel cobalt aluminum composite oxide (LiNi 0.8 Co 0.15 Al 0.05 O2), lithium nickel cobalt manganese composite oxide (LiNi 0.33 Co 0.33 Mn 0.33 O2, LiNi 0.4 Co 0.2 Mn 0.4 O2, LiNi 0.5 Co 0.2 Mn 0.3 O2, LiNi 0.6 Co 0.2 Mn 0.2 O2, LiNi 0.7 Co 0.15 Mn 0.15 O2, LiNi 0.8 Co 0.1 Mn 0.1 O2), manganese nickel oxide (LiNi 0.5 Mn 1.5 O4) but are not limited to these.

[0131] In particular, the polymer solid electrolyte according to one aspect is NCM811 (LiNi 0.8 Co 0.1 Mn 0.1 It has the advantage of excellent compatibility with high-capacity cathode materials such as O2.

[0132] The conductive material may include, but is not limited to, carbon black such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, summer black, etc.; conductive fibers such as carbon fibers and metal fibers; metal powders such as fluorinated carbon, aluminum, and nickel powders; conductive whiskeys such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide; and conductive materials such as polyphenylene derivatives, but is not particularly limited as long as it has conductivity and does not cause chemical changes in the battery.

[0133] The above binder polymer may include one or more selected from the group consisting of nitrile butadiene rubber, polyethylene glycol, polyacrylonitrile, polyvinyl chloride, polymethyl methacrylate, polypropylene oxide, polydimethylsiloxane, polyvinylidene fluoride, polyvinylidene carbonate, and polyvinylpyrrolidinone, and preferably one or more selected from the group consisting of polyvinylidene fluoride, polyvinylidene carbonate, and polyethylene glycol, but is not limited thereto.

[0134] The above negative electrode layer may include a negative electrode current collector and a negative electrode active material layer formed on the negative electrode current collector.

[0135] Non-limiting examples of the negative electrode current collector may be selected from a foil made of copper, gold, nickel, or a copper alloy or a combination thereof. The negative electrode active material layer may be any one or two or more selected from the group consisting of any one carbon selected from soft carbon, hard carbon, artificial graphite, natural graphite, expanded graphite, carbon fiber, non-graphitizable carbon, carbon black, carbon nanotubes, acetylene black, Ketjen black, graphene, fullerene, activated carbon, and meso carbon microbeads; any one metal selected from silicon, tin, lithium, aluminum, silver, bismuth, indium, germanium, lead, platinum, titanium, zinc, manganese, cadmium, cerium, copper, cobalt, nickel, and iron; an alloy comprising two or more of the above metals; and an oxide of one or more of the above metals; and preferably, lithium metal, but is not limited thereto.

[0136] In particular, the polymer solid electrolyte according to one aspect has excellent interfacial stability with a lithium metal negative electrode and effectively suppresses the dendrite growth phenomenon, thereby overcoming the limitations of conventional solid electrolytes.

[0137] In addition, one aspect of the present invention provides a device comprising an all-solid-state battery according to various aspects or embodiments of the present invention, wherein the device is selected from among a communication device, a transportation device, and an energy storage device.

[0138] Hereinafter, the above-described implementation examples will be described in more detail through examples. However, the following examples are for illustrative purposes only and do not limit the scope of the rights.

[0139] [Manufacturing Example 1] Preparation of zwitterionic compound (Ac11Py3TFSI)

[0140]

[0141] 1.5 equivalents of potassium(3-chloropropylsulfonylperfluoroalkylsulfonyl)imide and 1.0 equivalent of N-(11-hydroxyundecyl)pyrrolidine were dissolved in acetonitrile and reacted under reflux. After completion of the reaction, the product was precipitated in diethylether three or more times to obtain compound 11Py3TFSI (91%).

[0142] 1 H-NMR (500MHz, DMSO-d6, 23℃), δ(ppm): 1.25 (m, 14H), 1.39 (m, 2H), 1.64 (m, 2H), 2.04 (m, 6H), 3.08 (t,J=7, 2H), 3.21 (m, 2H), 3.36 (m, 4H), 3.47 (m, 4H), 4.34 (t,J=5, 1H).

[0143] Afterwards, 1.0 equivalent of the compound 11Py3TFSI, 3.0 equivalents of acryloyl chloride, and 4.0 equivalents of K2CO3 were dissolved in acetonitrile and reacted while refluxing with nitrogen gas. After completion of the reaction, the result was precipitated in diethylether three or more times to obtain the zwitterionic compound (N-(3-[1-(11-(acryloyloxy)undecyl)pyrrolidinium]propyl)sulfonyl)trifluoromethane-sulfonyl)imide (Ac11Py3TFSI) (87%).

[0144] 1H-NMR (500MHz, DMSO-d6, 23℃), δ(ppm): 1.26 (m, 14H), 1.59 (m, 2H), 1.64 (m, 2H), 2.04 (m, 6H), 3.08 (t,J=7, 2H), 3.21 (m, 2H), 3.36 (m, 2H), 3.47 (m, 4H), 4.09 (t,J=6.5, 2H), 5.93 (dd,3J=10,2J=1.4, 1H), 6.16 (dd,3J=16,3J=10, 1H), 6.31 (dd,3J=16,2J=1.4, 1H).

[0145] [Manufacturing Example 2] Preparation of zwitterionic compound (Ac11Py3SO3)

[0146]

[0147] 2.0 equivalents of 1,3-propanesultone and 1.0 equivalents of N-(11-hydroxyundecyl)pyrrolidine were dissolved in acetonitrile and reacted under reflux. After completion of the reaction, the product was precipitated in diethylether three or more times to obtain compound 11Py3SO3 (77%).

[0148] 1 H-NMR (500MHz, DO, 23℃), δ(ppm): 1.25 (m, 10H), 1.31 (m, 4H), 1.49 (m, 2H), 1.64 (m, 4H), 1.82 (m, 4H), 2.09 (m, 2H), 2.93 (t, J=7, 2H), 3.25 (m, 2H), 3.33 (m, 4H), 3.41 (m, 2H), 3.54 (t,J=6.5, 2H).

[0149] Afterwards, 1.0 equivalent of the compound 11Py3SO3, 3.0 equivalents of acryloyl chloride, and 4.0 equivalents of K2CO3 were dissolved in acetonitrile and reacted while refluxing with nitrogen gas. After completion of the reaction, the mixture was extracted with water / dichloromethane at least three times, and the organic layer was dried with MgSO4. After filtering to remove the solid, dichloromethane was evaporated to obtain the zwitterionic compound 1-(undecyl-11-acrylate)-1-(propyl-3-sulfonate) pyrrolidinium (Ac11Py3SO3) (91%).

[0150] 1 H-NMR (500MHz, CDCl3, 23℃), δ(ppm): 1.26 (m, 10H), 1.33 (m, 4H), 1.66 (m, 4H), 2.11 (m, 2H), 2.21 (m, 2H), 2.38 (m, 2H), 2.98 (m, 2H), 3.22 (m, 2H), 3.60 (m, 4H), 3.75 (m, 2H), 4.14 (t,J=7, 2H), 5.82 (dd,3J=10,2J=1.4, 1H), 6.11 (dd,3J=16,3J=10, 1H), 6.39 (dd,3J=16,2J=1.4, 1H).

[0151] [Manufacturing Example 3] Preparation of zwitterionic compound (Ac11Im3TFSI)

[0152]

[0153] 1.5 equivalents of potassium(3-chloropropylsulfonylperfluoroalkylsulfonyl)imide and 1.0 equivalent of 1-(11-hydroxyundecyl)imidazole were dissolved in acetonitrile and reacted under reflux. After completion of the reaction, the product was precipitated in diethylether three or more times to obtain compound 11Im3TFSI (86%).

[0154] 1 H-NMR (500MHz, DMSO-d6, 23℃), δ(ppm): 1.25 (m, 14H), 1.39 (m, 2H), 1.78 (m, 2H), 2.21 (m, 2H), 3.08 (t,J=7, 2H), 3.31 (m, 2H), 4.18 (m, 2H), 4.30 (m, 2H), 4.34 (t,J=5, 1H) 7.81 (s, 2H), 9.20 (s, 1H).

[0155] Afterwards, 1.0 equivalent of the compound 11Im3TFSI, 3.0 equivalents of acryloyl chloride, and 4.0 equivalents of K2CO3 were dissolved in acetonitrile and reacted while refluxing with nitrogen gas. After completion of the reaction, the result was precipitated in diethylether three or more times to obtain the zwitterionic compound N-(3-[3-(11-(acryloyloxy)undecyl)imidazolium]propyl)sulfonyl)trifluoromethane-sulfonyl)imide (Ac11Im3TFSI) (87%).

[0156] 1H-NMR (500MHz, DMSO-d6, 23℃), δ(ppm): 1.25 (m, 14H), 1.39 (m, 2H), 1.78 (m, 2H), 2.21 (m, 2H), 3.08 (t,J=7, 2H), 4.18-4.20 (m, 4H) 4.30 (m, 2H), 5.93 (dd, 3 J=10, 2 J=1.4, 1H), 6.16 (dd, 3 J=16, 3 J=10, 1H), 6.31 (dd, 3 J=16, 2 J=1.4, 1H), 7.81 (s, 2H), 9.20 (s, 1H).

[0157] [Manufacturing Example 4] Preparation of zwitterionic compound (Ac6Py3TFSI)

[0158]

[0159] 1.5 equivalents of potassium(3-chloropropylsulfonylperfluoroalkylsulfonyl)imide and 1.0 equivalent of N-(11-hydroxyhxyl)pyrrolidine were dissolved in acetonitrile and reacted under reflux. After completion of the reaction, the product was precipitated in diethylether three or more times to obtain compound 6Py3TFSI (85%).

[0160] 1 H-NMR (500MHz, DMSO-d6, 23℃), δ(ppm): 1.31 (m, 6H), 1.62 (m, 2H), 1.64 (m, 2H), 2.04 (m, 6H), 3.08 (t,J=7, 2H), 3.21 (m, 2H), 3.36 (m, 2H), 3.47 (m, 4H), 4.34 (t,J=5, 1H).

[0161] Afterwards, 1.0 equivalent of the compound 6Py3TFSI, 3.0 equivalents of acryloyl chloride, and 4.0 equivalents of K2CO3 were dissolved in acetonitrile and reacted while refluxing with nitrogen gas. After completion of the reaction, the result was precipitated in diethylether three or more times to obtain the zwitterionic compound N-(3-[1-(6-(acryloyloxy)hexyl)pyrrolidinium]propyl)sulfonyl)trifluoromethane-sulfonyl)imide (Ac6Py3TFSI) (82%).

[0162] 1 H-NMR (500MHz, DMSO-d6, 23℃), δ(ppm): 1.31 (m, 6H), 1.62 (m, 2H), 1.64 (m, 2H), 2.04 (m, 6H), 3.08 (t,J=7, 2H), 3.21 (m, 2H), 3.36 (m, 2H), 3.47 (m, 4H), 4.09 (t,J=6.5, 2H), 5.93 (dd, 3 J=10, 2 J=1.4, 1H), 6.16 (dd, 3 J=16, 3 J=10, 1H), 6.31 (dd, 3 J=16, 2 J=1.4, 1H).

[0163] [Manufacturing Example 5] Preparation of zwitterionic compound (Ac11Im2CO2)

[0164]

[0165] 1.5 equivalents of β-propiolactone and 1.0 equivalent of 1-(11-hydroxyundecyl)imidazole were dissolved in acetonitrile and reacted under reflux. After completion of the reaction, the product was precipitated in diethylether three or more times to obtain compound 11Im2CO2 (90%).

[0166] 1 H-NMR (500MHz, DMSO-d6, 23℃), δ(ppm): 1.25 (m, 14H), 1.39 (m, 2H), 1.78 (m, 2H), 2.08 (m, 2H), 3.31 (m, 2H), 3.81 (m, 2H), 4.18 (m, 2H), 4.34 (t,J=5, 1H) 7.81 (s, 2H), 9.20 (s, 1H).

[0167] Afterwards, 1.0 equivalent of the compound 11Im2CO2, 3.0 equivalents of acryloyl chloride, and 4.0 equivalents of K2CO3 were dissolved in acetonitrile and reacted while refluxing with nitrogen gas. After completion of the reaction, the mixture was precipitated in diethylether three or more times to obtain a zwitterionic compound (1-(undecyl-11-acrylate)-3-(ethyl-2-carboxylate) imidazolium (Ac11Im2CO2) (81%).

[0168] 1 H-NMR (500MHz, DMSO-d6, 23℃), δ(ppm): 1.25 (m, 14H), 1.39 (m, 2H), 1.78 (m, 2H), 2.08 (m, 2H), 4.18-4.20 (m, 4H) 4.30 (m, 2H), 5.93 (dd, 3 J=10, 2 J=1.4, 1H), 6.16 (dd, 3 J=16, 3 J=10, 1H), 6.31 (dd, 3 J=16, 2 J=1.4, 1H), 7.81 (s, 2H), 9.20 (s, 1H).

[0169]

[0170] [Example 1]

[0171] Manufacturing of polymer solid electrolytes

[0172] A solid electrolyte slurry composition was prepared by mixing the zwitterionic compound (Ac11Py3TFSI) obtained in the above Preparation Example 1, LiBETI, and benzoyl peroxide (BPO) in ethanol. At this time, the zwitterionic compound (1) and LiBETI were mixed in a molar ratio of 1:1.5, ethanol was 10 wt% of the zwitterionic compound (1), and BPO was 1 wt% of the zwitterionic compound.

[0173] After the above solid electrolyte slurry composition was coated on a substrate using a doctor blade, all ethanol was evaporated at 80°C, and thermal polymerization was performed in an oven at 110°C to obtain a polymer solid electrolyte having a thickness of 30 μm.

[0174] Manufacturing of all-solid-state lithium metal batteries

[0175] A cathode material slurry was prepared by adding N-methylpyrrolidone to a cathode material content of 40 wt% in a weight ratio of cathode active material (NCM811) / conductive material (carbon black) / binder (polyvinylidene fluoride, PVDF) 94 / 3 / 3. The cathode material slurry was applied to an aluminum (Al) thin film having a thickness of 18 μm using a doctor blade, and dried with hot air at 80°C and then vacuum-dried at 120°C for 24 hours to form a cathode active material layer having a thickness of 20 μm. Thereafter, the solid electrolyte slurry composition obtained above was impregnated into the cathode active material layer, rolled with a roll press at 80°C, and thermally polymerized in an oven at 110°C, thereby manufacturing a cathode layer impregnated with a polymer solid electrolyte and a solid electrolyte layer integrated with the cathode layer having a thickness of 30 μm.

[0176] Afterwards, a 50 ㎛ thick lithium metal was rolled onto an 8 ㎛ thick copper foil current collector to form an all-solid-state lithium metal battery.

[0177] [Example 2]

[0178] A polymer solid electrolyte and an all-solid-state lithium metal battery were manufactured in the same manner as in Example 1, except that the zwitterionic compound (Ac11Py3SO3) manufactured in Manufacturing Example 2 was used instead of the zwitterionic compound (Ac11Py3TFSI) manufactured in Manufacturing Example 1.

[0179] [Example 2-1]

[0180] A polymer solid electrolyte and an all-solid-state lithium metal battery were manufactured in the same manner as in Example 1, except that the zwitterionic compound (Ac11Im3TFSI) manufactured in Manufacturing Example 3 was used instead of the zwitterionic compound (Ac11Py3TFSI) manufactured in Manufacturing Example 1.

[0181] [Example 2-2]

[0182] A polymer solid electrolyte and an all-solid-state lithium metal battery were manufactured in the same manner as in Example 1, except that the zwitterionic compound (Ac6Py3TFSI) manufactured in Manufacturing Example 4 was used instead of the zwitterionic compound (Ac11Py3TFSI) manufactured in Manufacturing Example 1.

[0183] [Example 2-3]

[0184] A polymer solid electrolyte and an all-solid-state lithium metal battery were manufactured in the same manner as in Example 1, except that the zwitterionic compound (Ac11Im2CO2) manufactured in Manufacturing Example 5 was used instead of the zwitterionic compound (Ac11Py3TFSI) manufactured in Manufacturing Example 1.

[0185] [Example 3]

[0186] An all-solid-state lithium metal battery was manufactured in the same manner as in Example 1, except that lithium iron phosphate (LFP, LiFePO4) was used instead of NCM811 as the positive electrode active material.

[0187] [Example 4]

[0188] Over-lithiated oxide (OLO, Li) is used instead of NCM811 as the cathode active material. 1.2 Mn 0.528 Co 0.096 Ni 0.176 An all-solid-state lithium metal battery was manufactured in the same manner as in Example 1 except that O2 was used.

[0189] [Comparative Example 1]

[0190]

[0191] A polymer solid electrolyte and an all-solid-state lithium metal battery were obtained in the same manner as in Example 1, except that polyethylene glycol diacrylate (PEGDA, number average molecular weight 20,000 g / mol) was used instead of the zwitterionic compound (Ac11Py3TFSI) prepared in Manufacturing Example 1.

[0192] [Comparative Example 2]

[0193] An all-solid-state lithium metal battery of Comparative Example 2 was manufactured in the same manner as Comparative Example 1, except that lithium iron phosphate (LFP, LiFePO4) was used instead of NCM811 as the positive electrode active material.

[0194] [Comparative Example 3]

[0195] Over-lithiated oxide (OLO, Li) is used instead of NCM811 as the cathode active material. 1.2 Mn 0.528 Co 0.096 Ni 0.176 An all-solid-state lithium metal battery of Comparative Example 3 was manufactured in the same manner as Comparative Example 1 except that O2 was used.

[0196]

[0197] <Evaluation example>

[0198] Evaluation 1. Ionic Conductivity

[0199] The polymer solid electrolytes manufactured in the above examples and comparative examples were laminated between two identical stainless steel foils to manufacture an ionic conductivity measurement cell, and the ionic conductivity of the polymer solid electrolytes was measured. Based on EIS (Electrochemical Impedance Spectroscopy) analysis, the impedance was measured and the ionic conductivity was calculated by applying an AC amplitude of 10 mV at a frequency range of 0.1 mHz to 3 MHz at room temperature. The results are shown in Table 1 below.

[0200] Evaluation 2. Lithium ion yield

[0201] A lithium ion yield measurement cell was manufactured by layering the polymer solid electrolytes manufactured in the above examples and comparative examples between two identical lithium metal foils, applying a direct current voltage of 10 mV at room temperature for 1 hour, and measuring the impedance values ​​before and after the application of the direct current voltage to calculate the lithium ion yield. The results are shown in Table 1 below.

[0202] Ionic Conductivity (mS / cm) Lithium Ion Yield Example 1 (Ac11Py3TFSI) 0.38 0.78 Example 2 (Ac11Py3SO3) 0.11 0.65 Comparative Example 1 (PEGDA) 0.048 0.47 Example 2-1 (Ac11Im3TFSI) 0.093 Example 2-2 (Ac6Py3TFSI) 0.089 Example 2-3 (Ac11Im2CO2) 0.076

[0203]

[0204] As shown in Table 1 above, it was confirmed that the polymer solid electrolyte of the example had significantly improved ionic conductivity and lithium ion yield compared to the polymer solid electrolyte of the comparative example.

[0205] Evaluation 3. Life Characteristics Evaluation

[0206] The room temperature life characteristics of the all-solid-state lithium metal batteries manufactured in the above Examples and Comparative Examples were analyzed. Specifically, the initial charge / discharge capacity of each all-solid-state lithium metal battery was observed at room temperature (25°C) in the voltage range of 2.5 to 4.0 (LFP, Example 3, Comparative Example 2), 2.95 to 4.25 (NCM811, Example 1, Comparative Example 1), and 2.0 to 4.75 (OLO, Example 4, Comparative Example 3) V at a current of 0.1 C (= 0.1 mA / cm2), and the life characteristics of the lithium batteries were observed by repeating the charge / discharge cycle 500 (LFP), 250 (NCM811), and 100 (OLO) times under a current of 0.1 C (= 0.1 mA / cm2), and the results are shown in FIGS. 1 to 3.

[0207] Referring to FIGS. 1 to 3, it can be seen that the all-solid-state lithium metal batteries to which the zwitter polymer solid electrolyte of the examples was applied all exhibited excellent capacity retention rates of 80% or more, regardless of the type of positive electrode active material. On the other hand, the all-solid-state lithium metal batteries to which the polymer solid electrolyte of the comparative examples was applied showed significantly lower capacity retention rates of 44.1% (Comparative Example 1) and 30.1% (Comparative Example 2), and in particular, in the case of Comparative Example 3 to which the OLO positive electrode active material was applied, it was confirmed that no capacity was developed after 5 cycles.

[0208] In addition, although not explicitly shown in the drawings of the present specification, etc., the life characteristics of the lithium batteries were observed by repeating the charge / discharge cycles 500 (LFP), 250 (NCM811), and 100 (OLO) under the same conditions as above for the all-solid-state lithium metal batteries to which the polymer solid electrolytes manufactured in Examples 2-1 to 2-3 were applied, and it was confirmed that all of the all-solid-state lithium metal batteries manufactured in these Examples stably achieved an excellent capacity retention rate of 80% or more regardless of the type of positive electrode active material.

[0209]

[0210] In summary, it can be seen that the zwitterionic polymer solid electrolyte according to one aspect of the present invention not only has high ionic conductivity that can be operated at room temperature, but also has excellent miscibility with high-capacity positive electrode materials such as NCM811, OLO, etc. and excellent interfacial stability with a lithium metal negative electrode, so that it has excellent life characteristics.

[0211] As described above, the present invention has been described by limited embodiments, but these are provided only to help a more general understanding of the present invention, and the present invention is not limited to the above embodiments, and those skilled in the art to which the present invention pertains can make various modifications and variations based on this description.

[0212] Therefore, the idea of ​​the present invention should not be limited to the described embodiments, and all things that are equivalent or equivalent to the following claims as well as the claims are considered to fall within the scope of the idea of ​​the present invention.

Claims

1. A polymer solid electrolyte comprising a zwitterionic polymer and a metal salt, the zwitterionic polymer including a structural unit derived from a zwitterionic compound represented by the following chemical formula 1. [Chemical Formula 1] R1 is hydrogen or methyl; p is an integer from 1 to 20; q is an integer from 1 to 20; X + Is , or and; R2 to R5 are each independently hydrogen or (C1-C7)alkyl, or R2 and R3, and R4 and R5 may be connected to each other to form an alicyclic ring or an aromatic ring; R6 is fluoro or fluoro(C1-C7)alkyl.

2. In paragraph 1, The above zwitterionic compound is a polymer solid electrolyte represented by the following chemical formula 2 or 3. [Chemical Formula 2] [Chemical Formula 3] In the above chemical formulas 2 and 3, R 11 is fluoro or fluoro(C1-C7)alkyl; R1, X + , p and q are the same as defined in chemical formula 1 of the first paragraph.

3. In paragraph 2, A polymer solid electrolyte, wherein p is an integer from 10 to 20 and q is an integer from 1 to 7.

4. In paragraph 3, The above zwitterionic compound is a polymer solid electrolyte represented by the following chemical formulas 4 to 6. [Chemical Formula 4] [Chemical Formula 5] [Chemical Formula 6] In the above chemical formulas 4 to 6, R1 is hydrogen or methyl; n is an integer from 1 to 7; X + Is , , or and; R6 and R7 are each independently hydrogen or (C1-C7)alkyl.

5. In paragraph 1, A polymer solid electrolyte, wherein the above zwitterionic polymer and metal salt are included in a weight ratio of 1:0.05 to 1.

5.

6. In paragraph 1, The above metal salt is a lithium salt, polymer solid electrolyte.

7. A step of preparing a solid electrolyte slurry composition by mixing a zwitterionic compound represented by the following chemical formula 1, a metal salt, and an organic solvent; and A method for producing a polymer solid electrolyte, comprising the steps of applying the above solid electrolyte slurry composition to a substrate and thermally polymerizing a zwitterionic compound. [Chemical Formula 1] In the above chemical formula 1, R1, X + , Y - , p and q are the same as defined in chemical formula 1 of the first paragraph.

8. In paragraph 7, A method for producing a polymer solid electrolyte, wherein the solid electrolyte slurry composition comprises a zwitterionic compound and a metal salt in a molar ratio of 1:0.1 to 2.

9. In paragraph 7, A method for producing a polymer solid electrolyte, wherein the solid electrolyte slurry composition comprises 5 to 30 parts by weight of an organic solvent per 100 parts by weight of a zwitterionic compound.

10. In paragraph 7, A method for producing a polymer solid electrolyte, wherein the above polymerization is a thermal polymerization performed under conditions of 110 to 150°C.

11. An all-solid-state battery comprising a polymer solid electrolyte selected from any one of claims 1 to 6.

12. In paragraph 10, An all-solid-state battery comprising a cathode layer, a solid electrolyte layer, and a negative electrode layer, wherein the solid electrolyte layer comprises a polymer solid electrolyte selected from any one of claims 1 to 6.

13. In paragraph 12, An all-solid-state battery, wherein the positive electrode layer is impregnated with a polymer solid electrolyte selected from any one of claims 1 to 6, and the positive electrode layer and the solid electrolyte layer are integrated with each other.

14. In paragraph 12, An all-solid-state battery, wherein the solid electrolyte layer has a thickness of 30 to 100 ㎛.

15. In paragraph 12, The above negative electrode layer includes a negative electrode current collector and a negative electrode active material layer, An all-solid-state battery, wherein the negative active material layer is lithium metal.

16. A device comprising the all-solid-state battery of paragraph 12, The above device is a device selected from among a communication device, a transportation device, and an energy storage device.

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