Method for preparing composite electrolyte

Abstract

The present disclosure relates to a method for preparing a composite electrolyte, the method comprising: preparing a slurry containing inorganic particles, a polymer component, a crosslinking agent, an initiator, and an electrolyte; applying the slurry to one surface or both surfaces of a substrate layer to obtain a coating structure; and irradiating the coating structure with ultraviolet light to obtain a composite electrolyte, wherein the content of the crosslinking agent in the slurry, the content of the initiator in the slurry, and the amount of ultraviolet light are adjusted.

Description

Method for manufacturing a complex electrolyte

[0001] The present disclosure relates to a method for manufacturing a composite electrolyte.

[0002] Composite electrolytes are considered as a technology to suppress the risk of battery ignition associated with the use of liquid electrolytes. A composite electrolyte can refer to a gel electrolyte in which inorganic particles are composited. The mechanical strength of a composite electrolyte can be higher than that of a liquid electrolyte. However, the mechanical strength of the composite electrolyte may decrease as the gel electrolyte repeatedly swells and contracts due to the expansion and contraction of the electrodes during cycling. A decrease in the mechanical strength of the composite electrolyte can lead to a degradation of battery performance.

[0003] The present disclosure aims to provide a method for manufacturing a composite electrolyte having improved mechanical strength.

[0004] In addition, the present disclosure aims to provide a method for manufacturing a composite electrolyte capable of uniformly curing a slurry.

[0005] The method for manufacturing a composite electrolyte of the present disclosure comprises: preparing a slurry comprising inorganic particles, a polymer component, a crosslinking agent, an initiator, and an electrolyte; applying the slurry to one or both sides of a substrate layer to obtain a coating structure; and exposing the coating structure to ultraviolet light at 800 mJ / cm² 2 A composite electrolyte is obtained by irradiating with the above amount of light; wherein the crosslinking agent content of the slurry is within the range of 10% by weight to 25% by weight. Additionally, the initiator content of the slurry is within the range of 1% by weight to 10% by weight relative to 100% by weight of the crosslinking agent, the electrolyte comprises a non-aqueous solvent and a lithium salt, and the linear carbonate content of the non-aqueous solvent is higher than the ethylene carbonate content.

[0006] The total content of the inorganic particles and the polymer components of the above slurry may be in the range of 250 to 350 parts by weight relative to 100 parts by weight of the crosslinking agent.

[0007] The above crosslinking agent may include a monomeric crosslinking agent and a polymeric crosslinking agent.

[0008] The above crosslinking agent may include one or more selected from the group consisting of triethylene glycol diacrylate (TEGDA), triethylene glycol dimethacrylate (TEGDMA), polyethylene glycol diacrylate (PEGDA), polyethylene glycol dimethacrylate (PEGDMA), polyurethane diacrylate (PUDA), polyurethane dimethacrylate (PUDMA), trimethylol propane triacrylate (TMPTA), trimethylol propane trimethacrylate (TMPTMA), 1,6-hexanediol diacrylate (HDDA), and 1,6-hexanediol dimethacrylate (HDDMA).

[0009] The above initiator may include one or more selected from the group consisting of short-wavelength photopolymerization initiators and long-wavelength photopolymerization initiators.

[0010] The above initiator may include one or more selected from the group consisting of IRGACURE 127 (2-Hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]-phenyl}-2-methyl-propan-1-one), DMPA (2,2-dimethoxy-2-phenylacetonephenone), HOMPP (2-hydroxy-2-methylpropipphenone) and LAP (Lithium phenyl-2,4,6-trimethylbenzoylphosphinate), or one or more selected from the group consisting of Bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide and Ethyl (2,4,6-trimethylbenzoyl) phenylphosphinate.

[0011] The thickness of the above substrate layer may be in the range of 5 μm to 20 μm.

[0012] In obtaining the above coating structure, the slurry can be applied to the substrate layer with a thickness of 30 μm to 45 μm.

[0013] The above substrate layer may be a porous substrate layer comprising a polyolefin-based polymer.

[0014] The inorganic particle content of the above slurry may be greater than or equal to the polymer component content.

[0015] The above-mentioned inorganic particles may include one or more selected from the group consisting of lithium-containing metal oxides and lithium-non-containing metal oxides.

[0016] The above lithium-containing metal oxide may include one or more selected from the group consisting of lithium aluminum germanium phosphate (LAGP)-based compounds, lithium lanthanum zirconium oxide (LZO)-based compounds, lithium aluminum titanium phosphate (LATP)-based compounds, lithium lanthanum zirconium tantalum oxide (LLZTO)-based compounds, lithium silicon titanium phosphate (LSTP)-based compounds, and lithium oxide.

[0017] The above lithium-free metal oxide may include one or more selected from the group consisting of zinc oxide (ZnO), calcium carbonate (CaCO3), silicon dioxide (SiO2), boehmite (AlO(OH)), alumina (Al2O3), barium titanate (BaTiO3), and titanium dioxide (TiO2).

[0018] The above polymer component may include one or more selected from the group consisting of polyvinylidene fluoride, poly(vinylidene fluoride-co-trichloroethylene), poly(vinylidene fluoride-co-chlorotrifluoroethylene), poly(vinylidene fluoride-co-trifluoroethylene), poly(vinylidene fluoride-co-tetrafluoroethylene), poly(vinylidene fluoride-co-hexafluoropropylene), spandex, butyl acrylate, polymethyl methacrylate, polyacrylonitrile, polyvinylpyrrolidone, and polyvinyl acetate.

[0019] The above electrolyte may further include an electrolyte additive.

[0020] The above-mentioned non-aqueous solvent may include one or more selected from the group consisting of propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethylmethyl carbonate (EMC), and gamma butyrolactone (γ-butyrolactone).

[0021] The above lithium salt may include one or more selected from the group consisting of LiTFSi, LiFSi, LiPF6, LiBF4, LiCl, LiBr, LiI, LiClO4, LiAsF6, LiCH3CO2, LiCF3SO3, LiN(CF3SO2)2, LiN(FSO2)2, and LiC(CF2SO2)3.

[0022] The present disclosure can provide a method for manufacturing a composite electrolyte having improved mechanical strength.

[0023] In addition, the present disclosure can provide a method for manufacturing a composite electrolyte capable of uniformly curing a slurry.

[0024] The present disclosure is described in detail below.

[0025] In this specification, “within range” includes each upper and lower limit. For example, if it is stated as within the range of 1 to 9, it includes 1 and 9, respectively.

[0026] The method for manufacturing a composite electrolyte of the present disclosure may include preparing a slurry. The slurry may include inorganic particles, a polymer component, a crosslinking agent, an initiator, and an electrolyte.

[0027] The method for manufacturing a composite electrolyte of the present disclosure may include obtaining a coating structure. In obtaining the coating structure, the slurry may be applied to one or both sides of a substrate layer.

[0028] The method for manufacturing the composite electrolyte of the present disclosure involves irradiating the coating structure with ultraviolet light at 800 mJ / cm² 2 It may include obtaining a complex electrolyte by irradiating with an amount of light greater than or equal to the above.

[0029] In the method for manufacturing a composite electrolyte of the present disclosure, the crosslinking agent content of the slurry is in the range of 10% by weight to 25% by weight, and the initiator content of the slurry is in the range of 1% by weight to 10% by weight relative to 100% by weight of the crosslinking agent.

[0030] In the method for manufacturing a composite electrolyte of the present disclosure, obtaining a coating structure may be performed after preparing a slurry. In the method for manufacturing a composite electrolyte of the present disclosure, obtaining a composite electrolyte may be performed after obtaining a coating structure.

[0031] In the present disclosure, the composite electrolyte may comprise a polymer component impregnated with an electrolyte and inorganic particles composited therewith. In this respect, the composite electrolyte of the present disclosure differs from the structure of a conventional electrolyte and separator comprising a battery case housing an anode, a cathode, and a separator disposed between the anode and the cathode, and an electrolyte injected into the interior thereof.

[0032] The composite electrolyte of the present disclosure may include a substrate layer and an active layer disposed on one or both sides of the substrate layer. The active layer may be formed from the slurry. Alternatively, the active layer may be manufactured from the slurry. For example, the active layer may be formed by applying the slurry to one or both sides of the substrate layer and then curing it.

[0033] The above substrate layer may be porous. A fluid can move from one side of the substrate layer to another through the pores of the substrate layer. A charge carrier (e.g., lithium ions) can move efficiently through the pores.

[0034] The above substrate layer may include a porous polyolefin-based film.

[0035] Here, a polyolefin-based porous film refers to a porous film containing a polyolefin resin as a main component.

[0036] The above polyolefin-based porous film may contain the polyolefin-based resin in an amount of 50 volume% or more, 90 volume% or more, or 95 volume% or more of the total material constituting the polyolefin-based porous film.

[0037] The weight average molecular weight of the component included in the above polyolefin resin is 3×10 5 Up to 15×10 6 It may be possible. If the weight average molecular weight of the component included in the above polyolefin resin is 1 million or more, the strength of the separator including the above polyolefin porous film may be improved.

[0038] The above polyolefin-based resin may include a thermoplastic resin. The above thermoplastic resin may include a homopolymer (e.g., polyethylene, polypropylene, polybutene) or copolymer (e.g., ethylene-propylene copolymer) formed by polymerizing monomers such as ethylene, propylene, 1-butene, 4-methyl-1-pentene, and 1-hexene.

[0039] The above polyolefin-based porous film may be a layer comprising the polyolefin resin alone, or a layer comprising two or more of the polyolefin resins. Among these, polyethylene and high molecular weight polyethylene having ethylene as a main backbone can stop (shut down) the flow of excessive current at a lower temperature. In addition, the polyolefin-based porous film may additionally include components other than the polyolefin resin that do not impair the function of the film.

[0040] The above slurry may include a polymer component and an electrolyte impregnated into the polymer component. As a result of impregnation by the electrolyte, the polymer component may swell. The swollen polymer component may have a gel phase.

[0041] The polymer component can form the framework of the slurry and immerse the electrolyte. Additionally, the polymer component may have appropriate crystallinity and polarity so that the composite electrolyte or the battery to which the composite electrolyte is applied may exhibit appropriate ionic conductivity. In particular, the polymer component may have a polar portion, and this portion may combine with a crosslinking agent described later. In this case, the polymer component may form a crosslinked structure in the slurry.

[0042] The above polymer component may include one or more selected from the group consisting of polyvinylidene fluoride, poly(vinylidene fluoride-co-trichloroethylene), poly(vinylidene fluoride-co-chlorotrifluoroethylene), poly(vinylidene fluoride-co-trifluoroethylene), poly(vinylidene fluoride-co-tetrafluoroethylene), poly(vinylidene fluoride-co-hexafluoropropylene), spandex, butyl acrylate, polymethyl methacrylate, polyacrylonitrile, polyvinylpyrrolidone, and polyvinyl acetate.

[0043] The above electrolyte may be impregnated into the polymer. The above electrolyte may comprise a non-aqueous solvent, a lithium salt, and an electrolyte additive. The lithium salt may be soluble in the non-aqueous solvent. The above electrolyte additive may be included in a predetermined manner to enable more stable charging and discharging of the battery to which the composite electrolyte is applied.

[0044] The above-mentioned non-aqueous solvent may refer to an organic solvent that does not contain water or, even if water is included, contains only trace amounts.

[0045] The above non-aqueous solvent may include one or more selected from the group consisting of cyclic carbonate solvents and linear carbonate solvents. The above non-aqueous solvent may each include a cyclic carbonate solvent and a linear carbonate solvent. The above non-aqueous solvent may include one or more selected from the group consisting of propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethylmethyl carbonate (EMC), and gamma-butyrolactone (γ-butyrolactone).

[0046] The above-mentioned non-aqueous solvent may include ethylene carbonate (EC) or propylene carbonate (PC) as a cyclic carbonate, and may also include a linear carbonate. A linear carbonate may refer to a compound having a straight-chain structure that includes monovalent alkyl groups on each side of the carbonate group. The alkyl group may be selected from the group consisting of methyl, ethyl, and propyl groups, but is not limited thereto. Examples of the above-mentioned linear carbonates include dimethyl carbonate (DMC), ethylmethyl carbonate (EMC), and diethyl carbonate (DEC).

[0047] The above-mentioned non-aqueous solvent may include ethylene carbonate as a cyclic carbonate, and together with this, may include one or more selected from the group consisting of dimethyl carbonate, ethylmethyl carbonate, and diethyl carbonate as linear carbonates. For example, the above-mentioned non-aqueous solvent may include ethylene carbonate and ethylmethyl carbonate, ethylene carbonate and diethyl carbonate, or ethylene carbonate and dimethyl carbonate.

[0048] The linear carbonate content of the above-mentioned non-aqueous solvent may be higher than the cyclic carbonate content. When different types of solvents are included as the linear carbonates of the above-mentioned non-aqueous solvent, the total content of linear carbonates included in the solvent may be higher than the content of cyclic carbonates.

[0049] When the above-mentioned non-aqueous solvent includes ethylene carbonate as a cyclic carbonate and also includes a linear carbonate, the content of the linear carbonate may be higher than the content of the ethylene carbonate.

[0050] For example, when the above-mentioned non-aqueous solvent includes ethylene carbonate and ethyl methyl carbonate, the volume ratio of ethyl methyl carbonate may be higher than the volume ratio of ethylene carbonate. When the above-mentioned non-aqueous solvent includes ethylene carbonate and dimethyl carbonate, the volume ratio of dimethyl carbonate may be higher than the volume ratio of ethylene carbonate. When the above-mentioned non-aqueous solvent includes ethylene carbonate and diethyl carbonate, the volume ratio of diethyl carbonate may be higher than the volume ratio of ethylene carbonate.

[0051] The content of the cyclic carbonate of the above-mentioned non-aqueous solvent may be 0.5 to 49.5 relative to the total content of the above-mentioned non-aqueous solvent, which is 100.

[0052] Preferably, it may be 1.0 or more, 2.0 or more, 3.0 or more, 4.0 or more, 5.0 or more, 6.0 or more, 7.0 or more, 8.0 or more, 9.0 or more, 10.0 or more, 11.0 or more, 12.0 or more, 13.0 or more, 14.0 or more, 15.0 or more, 16.0 or more, 17.0 or more, 18.0 or more, 19.0 or more, 20.0 or more, and 49.0 or less, 48.0 or less, 47.0 or less, 46.0 or less, 45.0 or less, 44.0 or less, 43.0 or less, 42.0 or less, 41.0 or less, 40.0 or less.

[0053] More preferably, it may be 21.0 or higher, 22.0 or higher, 23.0 or higher, 24.0 or higher, 25.0 or higher, 26.0 or higher, 27.0 or higher, 28.0 or higher, and 29.0 or higher, and may be 39.0 or lower, 38.0 or lower, 37.0 or lower, 36.0 or lower, 35.0 or lower, 34.0 or lower, 33.0 or lower, 32.0 or lower, and 31.0 or lower.

[0054] The content of the linear carbonate of the above non-aqueous solvent may be 50.5 to 99.5 relative to the total content of the above non-aqueous solvent, which is 100.

[0055] Preferably, it may be 51.0 or higher, 52.0 or higher, 53.0 or higher, 54.0 or higher, 55.0 or higher, 56.0 or higher, 57.0 or higher, 58.0 or higher, 59.0 or higher, 60.0 or higher, and 99.0 or lower, 98.0 or lower, 97.0 or lower, 96.0 or lower, 95.0 or lower, 94.0 or lower, 93.0 or lower, 92.0 or lower, 91.0 or lower, 90.0 or lower, 89.0 or lower, 88.0 or lower, 87.0 or lower, 86.0 or lower, 85.0 or lower, 84.0 or lower, 83.0 or lower, 82.0 or lower, 81.0 or lower.

[0056] More preferably, it may be 61.0 or higher, 62.0 or higher, 63.0 or higher, 64.0 or higher, 65.0 or higher, 66.0 or higher, 67.0 or higher, 68.0 or higher, and 69.0 or higher, and may be 80.0 or lower, 79.0 or lower, 78.0 or lower, 77.0 or lower, 76.0 or lower, 75.0 or lower, 74.0 or lower, 73.0 or lower, 72.0 or lower, and 71.0 or lower.

[0057] The content of each of the cyclic carbonate and linear carbonate of the above-mentioned non-aqueous solvent is controlled as described above, thereby increasing the solubility of the polymer binder and preventing an increase in the viscosity of the coating slurry.

[0058] Among the solvents included in the above non-aqueous solvent, the content of the solvent existing as a solid phase at room temperature may be less than the content of the solvent existing as a liquid phase at room temperature. Room temperature refers to 20°C to 30°C, and may be, for example, 25°C.

[0059] The above lithium salt may refer to a material that decomposes into lithium cations and anions upon dissociation. The above lithium salt may include one or more selected from the group consisting of LiTFSi, LiFSi, LiPF6, LiBF4, LiCl, LiBr, LiI, LiClO4, LiAsF6, LiCH3CO2, LiCF3SO3, LiN(CF3SO2)2, LiN(FSO2)2, and LiC(CF2SO2)3.

[0060] The above electrolyte additive may include one or more selected from the group consisting of vinylene carbonate (VC), fluoroethylene carbonate (FEC), 1,3-propane sulfone (PS), 1,3-propene sulfone (PRS), ethylene sulfate (Esa), and trimethylene sulfate (TMS).

[0061] The above electrolyte may contain the above electrolyte additive in a range of, for example, 1% to 5% by weight.

[0062] The above slurry may further include inorganic particles. The inorganic particles may participate in the transport of lithium ions to improve the performance of the battery to which the composite electrolyte is applied. The inorganic particles may also impart heat resistance, heat insulation, heat endothermic properties, etc. to the composite electrolyte, thereby protecting the composite electrolyte from external mechanical and / or thermal stimuli.

[0063] The content of the inorganic particles in the above slurry may be greater than or equal to the content of the polymer component. Preferably, the content of the inorganic particles may be higher than that of the polymer component. Among the inorganic particles, polymer component, and electrolyte constituting the slurry, the inorganic particles may be included in a larger amount in the slurry than the other two components excluding the electrolyte.

[0064] The fact that the above inorganic particles are contained in the slurry in greater quantities than the polymer component may mean that the weight of the inorganic particles is higher than the weight of the polymer component based on the slurry.

[0065] The above-mentioned inorganic particles may include one or more selected from the group consisting of lithium-containing metal oxides and lithium-non-containing metal oxides.

[0066] The above lithium-containing metal oxide is lithium aluminum germanium phosphate (LAGP; Li 1+x Al x Ge 2-x (PO4)3, 0≤x≤2))-based compound, lithium lanthanum zirconium oxide (LLZO; Li 7-x La3Zr 2-x M x O 12, M is a doping element (one or more selected from the group consisting of Al, Ga, Fe, Ta, Nb, W, Mo, Hf, Ti, or combinations thereof), and a compound of the 0≤x≤2 type, lithium aluminum titanium phosphate (LATP; Li 1+x Al x Ti2-x (PO4)3, 0≤x≤2)-based compound, lithium silicon titanium phosphate (LSTP; Li 1+x Si x Ti 2-x (PO4) 3, It may include one or more selected from the group consisting of 0≤x≤2) compounds and lithium oxides.

[0067] For example, the above lithium-containing metal oxide is LLZTO(Li 6.75 La3Zr 1.75 Ta 0.25 O 12 ), LLZO(Li7La3Zr2O 12 ), LLTO(Li5La3Ta2O 12 ), LLT(Li 0.33 La 0.55 Ti O3 ), Li3PO4, Li4SiO4, Li3BO3, LAGP(Li 1.5 Al 0.5 Ge 1.5 P3O 12 ), LATP(Li 1.3 Al 0.3 Ti 1.7 P3O 12 ), LLZ-Ta(Li7La3Zr 2-x Ta x O 12, 0≤x≤2), LLZ-Nb(Li7La3Zr 2-x Nb x O 12, 0≤x≤2) or it can be Li4SiO4-Li3PO4.

[0068] The above lithium-free metal oxide may include one or more selected from the group consisting of zinc oxide (ZnO), calcium carbonate (CaCO3), silicon dioxide (SiO2), boehmite (AlO(OH)), alumina (Al2O3), barium titanate (BaTiO3), and titanium dioxide (TiO2).

[0069] The above slurry may include the lithium-free metal oxide as the inorganic particles. The above slurry may include the boehmite (AlO(OH)) and the barium titanate (BaTiO3) as the inorganic particles.

[0070] The above barium titanate (BaTiO3) can be added to the slurry to reduce the moisture content of the membrane formed by the slurry. The boehmite (AlO(OH)) content of the slurry may be higher than the content of the barium titanate (BaTiO3). As a result, the amount of moisture generated in the slurry may be reduced.

[0071] In the present disclosure, the thickness of the substrate layer may be in the range of 5 μm to 20 μm. The thickness of the substrate layer to which the slurry is applied may be in the range of 5 μm to 20 μm.

[0072] In obtaining the above coating structure, the slurry can be applied to the substrate layer to a thickness of 30 μm to 45 μm.

[0073] After irradiating the ultraviolet rays to obtain the above composite electrolyte, the combined thickness of the substrate layer and the slurry may be 50 μm.

[0074] The above slurry may further include a crosslinking agent. The crosslinking agent may form a crosslinked structure with the polymer component in the slurry.

[0075] The above cross-linked structure may be formed by a bond between a polar functional group having the polymer component and a specific functional group having the cross-linking agent. The cross-linking agent may have a photoreactive functional group. The cross-linked structure of the polymer component may be formed by a bond between the polar functional group and the photoreactive functional group. The cross-linked structure of the polymer component may be formed by applying an external force to a mixture containing the polymer component and the cross-linking agent. Specifically, the cross-linked structure may be formed by applying heat or light to a mixture containing the polymer component and the cross-linking agent. More specifically, the cross-linked structure may be formed by applying light to a mixture containing the polymer component and the cross-linking agent.

[0076] The above crosslinked structure may be formed by at least two polymers being bonded together via a crosslinking agent. Since the crosslinking agent acts as a medium, the crosslinking agent may include two or more functional groups involved in the above crosslinked structure. The crosslinking agent may include two or more photoreactive functional groups.

[0077] The above crosslinking agent may include a (meth)acrylate group as the photoreactive functional group.

[0078] The above (meth)acrylate group may mean an acrylate group or a methacrylate group. The above (meth)acrylate group may mean a monovalent functional group derived from an ester of (meth)acrylic acid.

[0079] The crosslinking agent may include one or more selected from the group consisting of triethylene glycol diacrylate (TEGDA), triethylene glycol dimethacrylate (TEGDMA), polyethylene glycol diacrylate (PEGDA), polyethylene glycol dimethacrylate (PEGDMA), polyurethane diacrylate (PUDA), polyurethane dimethacrylate (PUDMA), trimethylol propane triacrylate (TMPTA), trimethylol propane trimethacrylate (TMPTMA), 1,6-hexanediol diacrylate (HDDA), and 1,6-hexanediol dimethacrylate (HDDMA). Since a crosslinking structure can be formed by light irradiation, the crosslinking agent may be a mixture comprising TMPTA or TMPAD and PUDA. The crosslinking agent may include one or more selected from the group consisting of monomeric crosslinking agents and polymeric crosslinking agents.

[0080] The above PUDA may be used to ensure the flexibility of the active layer. Meanwhile, when the crosslinking agent is a mixture containing the TMPTA and PUDA, the TMPA content of the mixture may be higher than the PUDA content of the mixture. That is, the mixture may include the PUDA as an additive. Since the reactivity of the PUDA is lower than that of the TMPTA, it is preferable to use the PUDA in a relatively small amount. The above slurry may further include an initiator. The initiator may be used when the crosslinking structure of the polymer is formed. Therefore, the above slurry may further include an initiator-derived component. The above slurry may further include a photopolymerization initiator-derived component.

[0081] The above photopolymerization initiator may include one or more selected from the group consisting of short-wavelength photopolymerization initiators and long-wavelength photopolymerization initiators.

[0082] The above short-wavelength photopolymerization initiator may include one or more selected from the group consisting of IRGACURE 127 (2-Hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]-phenyl}-2-methyl-propan-1-one), DMPA (2,2-dimethoxy-2-phenylacetonephenone), HOMPP (2-hydroxy-2-methylpropipphenone) and LAP (Lithium phenyl-2,4,6-trimethylbenzoylphosphinate).

[0083] The above long-wavelength photopolymerization initiator may include one or more selected from the group consisting of Bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide and Ethyl (2,4,6-trimethylbenzoyl) phenylphosphinate.

[0084] In the method for manufacturing a composite electrolyte of the present disclosure, the crosslinking agent content, the initiator content, and the slurry content may exhibit a predetermined relationship.

[0085] The crosslinking agent content of the slurry is within the range of 10% to 25% by weight, and the initiator content of the slurry may be within the range of 1% to 10% by weight relative to 100% by weight of the crosslinking agent. If the content of the crosslinking agent and the content of the initiator of the slurry are within the above ranges, crosslinking can proceed smoothly by the crosslinking agent and the initiator. As a result, the slurry can have excellent elasticity.

[0086] In addition, at this time, the polymer component and the inorganic particles can be uniformly dispersed within the slurry. In addition, at this time, the movement path of the charge carrier (e.g., lithium ion) is uniformly formed, so that the performance of the battery containing the composite electrolyte can be improved.

[0087] If the content of the crosslinking agent is less than 10 weight%, the content of the crosslinking agent relative to the electrolyte is low, so the inorganic particles, the polymer components, and the crosslinking agent may not be uniformly dispersed. As a result, crosslinking may not proceed sufficiently, which may reduce the elasticity of the slurry. In addition, at this time, the movement path of the charge carrier may be formed non-uniformly. Furthermore, the low-boiling point solvent may volatilize during the crosslinking process, which may improve the non-uniformity of the membrane. As a result, the performance of the battery containing the composite electrolyte may deteriorate.

[0088] If the content of the above-mentioned crosslinking agent is 25 weight % or more, the resistance of the composite electrolyte membrane may increase, and the ionic conductivity of the composite electrolyte membrane may decrease. As a result, the lifespan characteristics of the battery containing the composite electrolyte may be reduced, and the performance may deteriorate.

[0089] If the content of the above initiator exceeds 10 parts by weight per 100 parts by weight of the crosslinking agent, many crosslinking sites may be formed and the length of the crosslinking chain may be shortened. As a result, excellent elasticity may not be achieved. In addition, unreacted initiators may cause side reactions.

[0090] If the content of the initiator is less than 1 part by weight relative to 100 parts by weight of the crosslinking agent, the crosslinking rate is lowered, and the crosslinking process may take a long time. In addition, some of the crosslinking agents may not be able to form crosslinking sites.

[0091] Ultimately, the present disclosure can produce a composite electrolyte with optimal performance by comparing the content of the slurry and the initiator, and by comparing and adjusting the content of the initiator and the crosslinking agent.

[0092] In the method for manufacturing a composite electrolyte of the present disclosure, the inorganic particles, the polymer component, and the crosslinking agent content may exhibit a predetermined relationship.

[0093] The total content of the inorganic particles and the polymer component may be in the range of 250 to 350 parts by weight relative to 100 parts by weight of the crosslinking agent. If the total content of the inorganic particles and the polymer component of the slurry is within the above weight range, the lithium ions can be transported smoothly. In addition, the composite electrolyte may have heat resistance, heat insulation, heat endothermic properties, etc., and may be protected from external stimuli.

[0094] The present disclosure describes irradiating the coating structure with ultraviolet light at 800 mJ / cm² 2 The present disclosure includes obtaining a composite electrolyte by irradiating with a light intensity greater than 850 mJ / cm². 2 Above, 900 mJ / cm² 2 Above, 950 mJ / cm² 2 Above, or 1000 mJ / cm² 2 A complex electrolyte can be obtained by irradiating with the above amount of light.

[0095] The above ultraviolet light intensity is 800 mJ / cm² 2 If the value is lower, the above electrolyte may not harden. Additionally, crosslinking by the above crosslinking agent and the above initiator may not proceed. As a result, the performance and lifespan characteristics of the battery containing the above composite electrolyte may be degraded.

[0096] The present disclosure describes an ultraviolet light of 2000 mJ / cm² to the coating structure. 2 Below, 1900 mJ / cm² 2 Below, 1800 mJ / cm² 2 Below, 1700 mJ / cm² 2 Below, 1600 mJ / cm² 2 Less than, or 1500 mJ / cm² 2 A composite electrolyte can be obtained by irradiating with the following light intensity. The above ultraviolet light may be Ultraviolet A (UVA), Ultraviolet B (UVB), or Ultraviolet C (UVC).

[0097] The present disclosure is described in more detail below with reference to examples and comparative examples. However, the present disclosure is not limited to examples.

[0098]

[0099] [Preparation Example]

[0100] Example 1. Composite electrolyte

[0101] (1) A dispersion is prepared in which 10 g of a mixture of inorganic particles (first inorganic particle : second inorganic particle = 9 : 1 weight ratio) is dispersed in 74.7 g of electrolyte. Here, the first inorganic particle is boehmite ((D50): 0.4 μm, BET: 12 m 2 (approx. / g). The second inorganic particle is barium titanate (D50: 0.65 μm, BET: 3.75 m 2 It is about / g.

[0102] (2) As the above electrolyte, a non-aqueous organic solvent in which ethylene carbonate (EC) and ethyl methyl carbonate (EMC) are mixed in a volume ratio of 3:7, 1M LiTFSI, and 2% by weight of vinylene carbonate (VC) are dissolved is used.

[0103] (3) 5 g of the polymer PVDF-HFP (Kynar 2501, Arkema), 8 g of the crosslinking agent TMPTA, and 2 g of PUDA (Miramer PU2100, Miwon Specialty Chemical) are added to the above dispersion. Then, the above dispersion is stirred with a homogenizer, and then 0.3 g of the photopolymerization initiator HMPP is added to obtain a slurry with a solid content of 15%.

[0104] (4) The above slurry is applied to the upper and lower surfaces of a 5 μm thick polyethylene film using a dual slot die to obtain a coating structure.

[0105] (5) 1500 mJ / cm² in the coating structure 2 A complex electrolyte is obtained by irradiating ultraviolet light of a certain amount.

[0106]

[0107] Example 2. Composite electrolyte

[0108] A dispersion is prepared in which 10 g of a mixture (first inorganic particle : second inorganic particle = 9 : 1 weight ratio) as inorganic particles is dispersed in 59.25 g of electrolyte. The content of the crosslinking agent is adjusted to 25 g, and the content of the initiator is adjusted to 0.75 g. 1000 mJ / cm² in the coating structure 2 Ultraviolet light of a certain amount is irradiated. Except for this, the same process as in Example 1 is repeated.

[0109]

[0110] Example 3. Composite electrolyte

[0111] As the above electrolyte, a non-aqueous organic solvent in which ethylene carbonate (EC) and diethyl carbonate (DEC) are mixed in a volume ratio of 3:7, 1 M LiTFSI, and 2 wt% vinylene carbonate (VC) are dissolved is used. Except for this, the same process as in Example 1 is repeated.

[0112]

[0113] Example 4. Composite electrolyte

[0114] As the above electrolyte, a non-aqueous organic solvent in which ethylene carbonate (EC) and dimethyl carbonate (DMC) are mixed in a volume ratio of 3:7, 1 M LiTFSI, and 2 wt% vinylene carbonate (VC) are dissolved is used. Except for this, the same process as in Example 1 is repeated.

[0115]

[0116] Example 5. Composite electrolyte

[0117] As the above electrolyte, a non-aqueous organic solvent in which ethylene carbonate (EC) and ethyl methyl carbonate (EMC) are mixed in a volume ratio of 1:9, 1 M LiTFSI, and 2 wt% vinylene carbonate (VC) are dissolved is used. Except for this, the same process as in Example 1 is repeated.

[0118]

[0119] Example 6. Composite electrolyte

[0120] As the above electrolyte, a non-aqueous organic solvent in which ethylene carbonate (EC) and ethyl methyl carbonate (EMC) are mixed in a volume ratio of 4:6, 1 M LiTFSI, and 2 wt% vinylene carbonate (VC) are dissolved is used. Except for this, the same process as in Example 1 is repeated.

[0121]

[0122] Comparative Example 1. Complex electrolyte

[0123] A dispersion is prepared in which 10 g of a mixture (first inorganic particle : second inorganic particle = 9 : 1 weight ratio) as inorganic particles is dispersed in 59.25 g of electrolyte. The content of the initiator is adjusted to 0.75 g. 500 mJ / cm² in the coating structure 2 Ultraviolet light of a certain amount is irradiated. Except for this, the same process as in Example 1 is repeated.

[0124]

[0125] Comparative Example 2. Complex electrolyte

[0126] A dispersion is prepared in which 10 g of a mixture (first inorganic particle : second inorganic particle = 9 : 1 weight ratio) as inorganic particles is dispersed in 79.85 g of electrolyte. The crosslinking agent content is adjusted to 5 g, and the initiator content is adjusted to 0.15 g. Except for this, the same process as in Example 1 is repeated.

[0127]

[0128] Comparative Example 3. Complex electrolyte

[0129] A dispersion is prepared in which 10 g of a mixture (first inorganic particle : second inorganic particle = 9 : 1 weight ratio) as inorganic particles is dispersed in 54.10 g of electrolyte. The crosslinking agent content is adjusted to 30 g, and the initiator content is adjusted to 0.9 g. 1000 mJ / cm² in the coating structure 2Ultraviolet light of a certain amount is irradiated. Except for this, the same process as in Example 1 is repeated.

[0130]

[0131] Comparative Example 4. Complex electrolyte

[0132] A dispersion is prepared in which 10 g of a mixture (first inorganic particle : second inorganic particle = 9 : 1 weight ratio) as inorganic particles is dispersed in 73.50 g of electrolyte. The initiator content is adjusted to 1.5 g. Except for this, the same process as in Example 1 is repeated.

[0133]

[0134] [Evaluation Method]

[0135] 1. Ionic conductivity of complex electrolytes

[0136] A coin cell with a diameter of 20 mm and a thickness of 16 mm is prepared in which the composite electrolyte of the example and comparative example is placed between two SUS plates.

[0137] (2) The ionic conductivity of the coin cell is calculated by applying electrochemical impedance spectroscopy (EIS) to the electrical resistance measurement and by converting it using the Nyquist plot method. The electrical resistance measurement is performed under AC voltage conditions of an amplitude of 10 mV and a frequency of 1,000,000 to 1,000 Hz.

[0138] 2. Lifespan Characteristics of Complex Electrolytes

[0139] The lifespan characteristics of a battery to which a composite electrolyte according to the examples and comparative examples is applied are measured according to the following process.

[0140] (1) An anode slurry is prepared by mixing an anode active material, a conductive material, and a binder in a solvent in a weight ratio of 97.5:1.1:1.4 (anode active material:conductive material:binder). Here, the anode active material is LiNi 0.86 Co 0.05 Mn 0.12 Al 0.02It is O2 (manufactured by LG Chem). The conductive material is Super P. The binder is PVdF (Polyvinylidene fluoride). The solvent is NMP (N-Methyl-2-pyrrolidone).

[0141] (2) The above anode slurry is applied to an aluminum current collector with a thickness of 20 μm with a loading amount of 4.0 mAh / cm2.

[0142] (3) The above-described coated anode slurry is dried and rolled to produce an anode. The anode is 1.54 cm 2 It is cut to a size of (14 pi).

[0143] (4) Lithium metal is rolled onto a copper current collector 10 μm thick to produce a cathode with a total thickness of 30 μm. The cathode is 1.76 cm 2 It is cut to a size of (15 pi).

[0144] (5) The composite electrolyte according to the example and comparative example is 2.83 cm 2 It is cut to a size of (19 pi).

[0145] (6) The composite electrolyte is placed between the anode and the cathode to manufacture a 2032 type coin cell.

[0146] (7) The lifespan characteristics of the above coin cell are evaluated by comparing the capacity retention rate after 100 cycles of the above coin cell using SC (Small Cell Cycler, SC 05-0.1. Wonik P&E).

[0147] 3. Storage modulus (G') of composite electrolytes

[0148] The storage modulus of a battery to which a composite electrolyte according to the examples and comparative examples is applied is measured according to the following process.

[0149] (1) 2 ml of the slurry according to the example and comparative example is applied onto an aluminum current collector with a thickness of 20 μm.

[0150] (2) A bulk composite electrolyte is prepared by irradiating the coated slurry with ultraviolet light having an amount of light corresponding to each example and comparative example.

[0151] (3) A bulk composite electrolyte is placed in a rheometer (Texas Instruments, HR-10), and the storage modulus is measured under conditions set at 25°C and an angular frequency of 0.1 rad / s to 100 rad / s.

[0152] 4. Electrode interface resistance of composite electrolytes

[0153] The electrode interface resistance of the composite electrolyte according to the examples and comparative examples is measured according to the following process.

[0154] (1) An anode slurry is prepared by mixing an anode active material, a conductive material, and a binder in a weight ratio of 97.5:1.1:1.4 (anode active material:conductive material:binder). Here, the anode active material is LiNi 0.86 Co 0.05 Mn 0.12 Al 0.02 It is O2 (manufactured by LG Chem). The conductive material is Super P. The binder is PVdF. The solvent is NMP.

[0155] (2) The anode slurry has a thickness of 20 μm on an aluminum current collector with a thickness of 4.0 mAh / cm 2 It is applied with a loading amount.

[0156] (3) The above-described coated anode slurry is dried and rolled to produce an anode. The anode is 1.54 cm 2 It is cut to a size of (14 pi).

[0157] (4) Lithium metal is rolled onto a copper current collector 10 μm thick to produce a cathode with a total thickness of 100 μm. The cathode is 17.6 cm 2 It is cut to a size of (15 pi).

[0158] (5) The composite electrolyte according to the example and comparative example is 2.83 cm 2It is cut to a size of (19 pi).

[0159] (6) The composite electrolyte is placed between the anode and the cathode to manufacture a 2032 type coin cell.

[0160] (7) The electrode interface resistance of the coin cell is calculated by measuring electrical resistance using electrochemical impedance spectroscopy (EIS) and converting it using the Nyquist plot method. The electrode interface resistance measurement is performed by measuring electrical resistance under conditions of an amplitude of 10 mV and a frequency of 1,000,000 to 0.1 Hz.

[0161]

[0162] [Evaluation Results and Discussion]

[0163] The manufacturing method of the manufacturing example and the evaluation results of the composite electrolytes of the examples and comparative examples are described in Table 1 below.

[0164] Classification Unit Preliminary Comparative Example 1 2 3 4 5 6 1 2 3 4 Crosslinking agent content weight % 10 2 5 10 10 10 10 2 5 5 3 0 10 UV light intensity mJ / cm 2 1 5 00 10 00 15 00 15 00 15 00 15 00 15 00 15 00 Initiator / Crosslinking agent ratio % 3 3 3 3 3 3 3 15 Composite film thickness ㎛ 5 5 0 5 0 5 5 5 5 5 5 5 5 5 0 Storage modulus Pa 5 6 8 7 6 9 3 4 5 2 8 5 9 6 6 4 0 2 8 5 7 4 9 2 1 2 1 1 7 4 7 - 3 3 4 Ionic conductivity average mS / cm 3 2 5 1.0 2 3.4 3 3.0 6 3.4 5 3.1 4 1.4 2 3.5 0 0.7 6 3.0 1 Ionic conductivity Deviation mS / cm 0.05 0.05 0.05 0.05 0.07 0.05 0.3 20.4 0.08 0.06 Electrode interface resistance Ω 199 209 185 205 183 202 292 180 33 1255 Life characteristics %(100 th Cycle / 1 st cycle retention)95939392909175858270

[0165] Meanwhile, referring to Table 1, compared to Examples 1 to 6, Comparative Example 3 contained a large amount of the crosslinking agent in the slurry. As a result, the crosslinking reaction proceeded excessively, and the slurry was formed in a manner similar to a solid phase, and the storage modulus could not be measured.

Claims

1. Prepare a slurry comprising inorganic particles, a polymer component, a crosslinking agent, an initiator, and an electrolyte; Obtaining a coating structure by applying the slurry to one or both sides of a substrate layer; and UV radiation of 800 mJ / cm² to the above coating structure 2 Obtaining a complex electrolyte by irradiating with an amount of light greater than or equal to the above; comprising, The crosslinking agent content of the above slurry is within the range of 10% to 25% by weight, and the initiator content of the above slurry is within the range of 1% to 10% by weight relative to 100% by weight of the crosslinking agent, and The above electrolyte comprises a non-aqueous solvent and a lithium salt, and A method for preparing a composite electrolyte in which the content of linear carbonate in the above-mentioned non-aqueous solvent is higher than the content of ethylene carbonate.

2. In Paragraph 1, A method for preparing a composite electrolyte in which the total content of the inorganic particles and the polymer components of the slurry is within the range of 250 to 350 parts by weight relative to 100 parts by weight of the crosslinking agent.

3. In Paragraph 1, A method for preparing a composite electrolyte comprising a monomeric crosslinking agent and a polymeric crosslinking agent.

4. In Paragraph 1, A method for preparing a composite electrolyte comprising one or more crosslinking agents selected from the group consisting of triethylene glycol diacrylate (TEGDA), triethylene glycol dimethacrylate (TEGDMA), polyethylene glycol diacrylate (PEGDA), polyethylene glycol dimethacrylate (PEGDMA), polyurethane diacrylate (PUDA), polyurethane dimethacrylate (PUDMA), trimethylol propane triacrylate (TMPTA), trimethylol propane trimethacrylate (TMPTMA), 1,6-hexanediol diacrylate (HDDA), and 1,6-hexanediol dimethacrylate (HDDMA).

5. In Paragraph 1, A method for preparing a composite electrolyte comprising one or more initiators selected from the group consisting of short-wavelength photopolymerization initiators and long-wavelength photopolymerization initiators.

6. In Paragraph 5, A method for preparing a composite electrolyte comprising the above-mentioned initiator, one or more selected from the group consisting of IRGACURE 127 (2-Hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]-phenyl}-2-methyl-propan-1-one), DMPA (2,2-dimethoxy-2-phenylacetonephenone), HOMPP (2-hydroxy-2-methylpropipphenone), and LAP (Lithium phenyl-2,4,6-trimethylbenzoylphosphinate), or one or more selected from the group consisting of Bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide and Ethyl (2,4,6-trimethylbenzoyl) phenylphosphinate.

7. In Paragraph 1, A method for manufacturing a composite electrolyte in which the thickness of the substrate layer is within the range of 5 μm to 20 μm.

8. In Paragraph 1, In obtaining the above coating structure A method for manufacturing a composite electrolyte in which the above slurry is applied to the above substrate layer to a thickness of 30 μm to 45 μm.

9. In Paragraph 1, A method for manufacturing a composite electrolyte in which the above substrate layer is a porous substrate layer comprising a polyolefin-based polymer.

10. In Paragraph 1, A method for manufacturing a composite electrolyte in which the inorganic particle content of the above slurry is greater than or equal to the polymer component content.

11. In Paragraph 1, A method for manufacturing a composite electrolyte comprising one or more inorganic particles selected from the group consisting of lithium-containing metal oxides and lithium-non-containing metal oxides.

12. In Paragraph 11, A method for manufacturing a composite electrolyte comprising one or more selected from the group consisting of lithium-containing metal oxides, lithium aluminum germanium phosphate (LAGP)-based compounds, lithium lanthanum zirconium oxide (LLZO)-based compounds, lithium aluminum titanium phosphate (LATP)-based compounds, lithium lanthanum zirconium tantalum oxide (LLZTO)-based compounds, lithium silicon titanium phosphate (LSTP)-based compounds, and lithium oxides.

13. In Paragraph 11, A method for manufacturing a composite electrolyte comprising one or more selected from the group consisting of zinc oxide (ZnO), calcium carbonate (CaCO3), silicon dioxide (SiO2), boehmite (AlO(OH)), alumina (Al2O3), barium titanate (BaTiO3), and titanium dioxide (TiO2).

14. In Paragraph 1, A method for manufacturing a composite electrolyte comprising one or more polymer components selected from the group consisting of polyvinylidene fluoride, poly(vinylidene fluoride-co-trichloroethylene), poly(vinylidene fluoride-co-chlorotrifluoroethylene), poly(vinylidene fluoride-co-trifluoroethylene), poly(vinylidene fluoride-co-tetrafluoroethylene), poly(vinylidene fluoride-co-hexafluoropropylene), spandex, butyl acrylate, polymethyl methacrylate, polyacrylonitrile, polyvinylpyrrolidone, and polyvinyl acetate.

15. In Paragraph 1, The above electrolyte is a method for manufacturing a composite electrolyte that further includes an electrolyte additive.

16. In Paragraph 1, A method for preparing a composite electrolyte comprising one or more non-aqueous solvents selected from the group consisting of propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, tetrahydrofuran, N-methyl-2-pyrrolidone (NMP), ethylmethyl carbonate (EMC), and gamma-butyrolactone (γ-butyrolactone).

17. In Paragraph 1, A method for manufacturing a composite electrolyte comprising one or more lithium salts selected from the group consisting of LiTFSi, LiFSi, LiPF6, LiBF4, LiCl, LiBr, LiI, LiClO4, LiAsF6, LiCH3CO2, LiCF3SO3, LiN(CF3SO2)2, LiN(FSO2)2, and LiC(CF2SO2)3.