All-solid-state battery

Abstract

The present invention relates to an all-solid-state battery. The all-solid-state battery comprises a solid electrolyte layer comprising: a non-woven fabric formed of nanofibers; and a solid electrolyte filled in the non-woven fabric, wherein the nanofiber includes a fire extinguishing solution core and a polymer shell having a melting point (Tm) of 100-180 °C, and the amount of the non-woven fabric is 5-10 wt% on the basis of the total 100 wt% of the solid electrolyte layer.

Description

All-solid-state batteries

[0001] It's about all-solid-state batteries.

[0002] Recently, rapid developments have been made in electronic devices that use batteries, such as cell phones, laptop computers, and electric vehicles.

[0003] Lithium-ion secondary batteries are primarily used for these types of batteries, and currently commercialized lithium-ion secondary batteries use graphite, silicon, or a combination of these as their anode active materials. Despite the growing demand for higher energy densities, lithium secondary batteries using graphite, silicon, or a combination of these as anode active materials cannot meet this demand. Furthermore, safety issues are emerging regarding lithium secondary batteries.

[0004] Accordingly, the development of all-solid-state batteries using lithium metal as the cathode is underway. All-solid-state batteries are composed entirely of solid materials, specifically those using solid electrolytes. Because lithium metal has a large potential difference with the anode, it boasts a high average voltage and a theoretical capacity of approximately 3,860 mAh / g, enabling high energy density. Furthermore, solid electrolytes offer improved safety due to their reduced risk of fire.

[0005] One embodiment provides an all-solid-state battery exhibiting excellent safety.

[0006] One embodiment provides an all-solid-state battery comprising a nonwoven fabric made of nanofibers and a solid electrolyte layer including a solid electrolyte filled in the nonwoven fabric, wherein the nanofibers include a fire extinguishing agent core and a polymer shell having a melting point (Tm) of 100°C to 180°C, and the content of the nonwoven fabric is 5% to 10% by weight based on 100% by weight of the entire solid electrolyte layer.

[0007] An all-solid-state battery according to one embodiment may exhibit even better safety.

[0008] Figure 1 is a schematic diagram showing the operation of a solid electrolyte in an abnormally high temperature environment of an all-solid-state battery according to one embodiment.

[0009] Figure 2 is a cross-sectional view schematically showing an all-solid-state battery according to one embodiment.

[0010] Figure 3 is a cross-sectional view schematically showing an all-solid-state battery according to another embodiment.

[0011] Hereinafter, embodiments of the present invention will be described in detail. However, these are presented as examples and are not intended to limit the present invention. The present invention is defined solely by the scope of the claims set forth below.

[0012] The terminology used herein is for the purpose of describing exemplary embodiments only and is not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise.

[0013] “Combination of these” means a mixture, laminate, composite, copolymer, alloy, blend, reaction product, etc. of the components.

[0014] It should be understood that terms such as "include," "comprise," or "have" are intended to specify the presence of a feature, number, step, component, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, components, or combinations thereof.

[0015] Throughout this specification, when it is said that a part "includes" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0016] In addition, the terms "about", "substantially", etc. used throughout this specification are used in the sense of numerical values ​​or near numerical values ​​when manufacturing and material tolerances inherent to the meanings stated are presented, and are used to prevent unscrupulous infringers from unfairly exploiting disclosures that mention exact or absolute values ​​to aid understanding of this specification.

[0017] Throughout this specification, the description of “A and / or B” means “A or B or both.”

[0018] Unless otherwise specified herein, when a part such as a layer, film, region, plate, etc. is said to be “on” another part, this includes not only cases where it is “directly on” the other part, but also cases where there is another part in between.

[0019] In the present invention, "particle size" or "particle diameter" may be an average particle diameter. In addition, the average particle diameter may be defined as the average particle diameter (D50) based on 50% of the cumulative volume in a particle diameter distribution curve. The particle diameter may be measured by a method widely known to those skilled in the art, for example, by measuring with a particle size analyzer, or by measuring with a transmission electron microscope, a scanning electron microscope, or a field emission scanning electron microscope (FE-SEM). Alternatively, the average particle diameter (D50) may be obtained by measuring with a measuring device that utilizes dynamic light-scattering, performing data analysis to count the number of particles for each particle size range, and calculating from this. Alternatively, the average particle diameter (D50) may be measured using a laser diffraction method. When measuring by laser diffraction, more specifically, after the particles to be measured are dispersed in a dispersion medium, they are introduced into a commercially available laser diffraction particle size measuring device (e.g., Microtrac MT 3000) and irradiated with ultrasonic waves of approximately 28 kHz at an output of 60 W, and the average particle diameter (D50) based on 50% of the particle diameter distribution in the measuring device can be calculated.

[0020] "Thickness" may be measured, for example, from photographs taken with an optical microscope such as a scanning electron microscope.

[0021] One embodiment relates to an all-solid-state battery comprising a nonwoven fabric made of nanofibers and a solid electrolyte layer including a solid electrolyte filled in the nonwoven fabric.

[0022] The above nanofibers comprise a fire retardant core and a polymer shell having a melting point (Tm) of 100°C to 180°C.

[0023] The above nonwoven fabric may be included in the solid electrolyte layer in an amount of 5% to 10% by weight based on 100% by weight of the entire solid electrolyte layer.

[0024] Typically, the solid electrolyte layer of an all-solid-state battery has an ion transport mechanism through the surface and interior of the solid electrolyte, so the solid electrolyte is sintered to minimize pores and maximize interfacial adhesion between the solid electrolytes. A non-woven fabric is used to complement the physical properties of the sintered solid electrolyte and to help the solid electrolyte layer function as a self-standing layer. Therefore, the volume and weight occupied by the non-woven fabric in the solid electrolyte layer act as resistance. In one embodiment, a non-woven fabric that imparts a fire extinguishing function to a portion that would otherwise only function as resistance is included in the all-solid-state battery by using a fire extinguishing agent in the nanofibers that make up the non-woven fabric.

[0025] To be more specific about this, a solid electrolyte layer according to one embodiment includes a nonwoven fabric made of nanofibers including a fire extinguishing agent core and a polymer shell having a melting point (Tm) of 100°C to 180°C, and a solid electrolyte partially filled in the nonwoven fabric.

[0026] When an all-solid-state battery including such a solid electrolyte layer is abnormally operated, and the internal temperature of the battery excessively increases and becomes abnormally high above the operating temperature, as shown in Fig. 1, the fire extinguishing agent present in the core of the nanofibers is released and acts, thereby rapidly lowering the internal temperature of the battery. When the fire extinguishing agent core is released, the function of the battery is reduced through various mechanisms, allowing for early detection of a battery abnormality before the battery catches fire. Therefore, the safety of the battery can be greatly improved.

[0027] The melting point (Tm) of the polymer shell, for example, the polymer constituting the shell, may be from 100°C to 180°C, from 110°C to 180°C, or from 120°C to 180°C. The melting point (Tm) in the above range is a temperature lower than the melting temperature of lithium metal.

[0028] When the melting point (Tm) of the polymer is within the above range, when the internal temperature of the all-solid-state battery becomes high, particularly, 100°C to 180°C, when the polymer melts, the fire extinguishing agent core present inside the shell composed of the polymer may be eluted and released to the outside. The released fire extinguishing agent has excellent affinity for lithium and reacts with lithium, or the fire extinguishing agent forms a film on the surfaces of the negative and positive electrodes to prevent physical reaction with lithium, or the interfacial contact of the solid electrolyte is inhibited by a change in volume to lower ionic conductivity, or the heat energy of the surroundings is indirectly reduced to prevent fire from occurring, thereby further securing safety.

[0029] If the melting point (Tm) of the polymer is lower than the above range, the polymer melts even at a temperature suitable for use as an all-solid-state battery, making it unsuitable. If the melting point (Tm) of the polymer is higher than the above range, the polymer does not melt even when the internal temperature of the all-solid-state battery increases excessively, so the fire extinguishing agent core present inside is not eluted, and thus the effect of using a nonwoven fabric made of nanofibers according to one embodiment cannot be obtained.

[0030] Furthermore, since the solid electrolyte layer includes this nonwoven fabric, each unit cell ultimately includes this nonwoven fabric. Therefore, the effect can be immediately felt at the localized location where an anomaly occurs within the unit cell, further enhancing safety.

[0031] If the nonwoven fabric according to one embodiment is included only in the outermost cell of a stacked battery in which one or more unit cells are stacked, rather than in the solid electrolyte layer included within the unit potential, or in the center pin of a wound battery, it is difficult for the effect to appear immediately in a local location, and thus safety may be somewhat reduced.

[0032] In one embodiment, the polymer constituting the shell may be polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl halide, polyester, polyamide, polyurethane, polymethyl methacrylate, polystyrene, melamine, polyvinyl alcohol, nylon, or a combination thereof. In one embodiment, the polyvinyl halide may be polyvinyl fluoride, polyvinyl chloride, or a combination thereof.

[0033] In one embodiment, the fire extinguishing agent dissolves in a liquid or gaseous state when the polymer shell collapses at high temperatures, expanding its volume and disrupting the interface between the solid electrolyte. This reduces ionic conductivity, potentially locally degrading battery performance and rendering battery operation impossible. Furthermore, when the fire extinguishing agent dissolves in a liquid or gaseous state, it can reduce the surrounding thermal energy, suppressing temperature increases and thus preventing fires from occurring.

[0034] The above extinguishing agents are 1,1,1,2,2-pentafluoroethane (CF3CF2H, HFC-125), 1,1,1,2,3,3,3-heptafluoropropane (CF3CHFCF3), chlorotetrafluoroethane (CHClFCF3), dodecafluoro-2-methylpentan-3-one (FK-5-1-12, CF3CF2C(O)CF(CF3)2)), 1-chloro-1,2,2,2-tetrafluoroethane (C2HClF4, 2-chloro-1,1,1,2-tetrafluoroethane, (CHClFCF3, HCFC-124), decafluorocyclohexanone (perfluorocyclohexanone), 1,1,1,2,4,4,5,5,5-nonafluoro-2-trifluoromethyl-butan-3-one (CF3CF2C(O)CF(CF3)2(),1,1,1,2,4,5,5,5,6,6,6-octafluoro-2,4,-bis(trifluoromethyl)pentan-3-one (CF3)2CFC(O)CF(CF3)2), CF3CF2C(O)CF2CF2CF3, CF3C(O)CF(CF3)2, 1,1,1,3,3,4,4,5,5,6,6,7,7,8,8,8-hexadodecafluorooctan-2-one (CF3CF2CF2CF2CF2CF2C(O)CF3), 1,1,1,3,4,4,4-heptafluoro-3-trifluoromethylbutan-2-one (CF3C(O)CF(CF3)2), 1,1,1,2,4,4,5,5-octafluoro-2-trifluoromethylpentan-3-one (HCF2CF2C(O)CF(CF3)2), 1,1,1,2,4,4,5,5,6,6,6-undecafluoro-2-trifluoromethylhexan-3-one (CF3CF2CF2C(O)CF(CF3)2), 1-chloro-,1,1,3,4,4,4-hexafluoro-3-trifluoromethyl-butan-2-one ((CF3)2CFC(O)CF2Cl), 1,1,1,2,2,4,4,5,5,6,6,6-dodecafluorohexan-3-one (CF3CF2C(O)CF2CF2CF3),1,1,1,5,5,5-Hexafluoropentane-2-4-dione (CF3C(O)CH2C(O)CF3), 1,1,1,2,5,6,6,6-octafluoro-2,5-bis(trifluoromethyl)hexane-3,4-dione ((CF3)2CFC(O)C(O)C(O)CF(CF3)2), 1,1,1,2,2,3,3,5,5,6,6,7,7,7-tetradecafluoroheptan-4-one (CF3CF2CF2C(O)CF2CF2CF3), 1,1,1,3,3,4,4,4-octafluorobutal-2-one (CF3C(O)CF2CF3), 1,1,2,2,4,5,5,5-Octafluoro-1-trifluoromethoxy-4-trifluoromethylpentan-3-one (CF3OCF2CF2C(O)CF(CF3)2), 1,1,1,2,4,4,5,5,6,6,7,7,7-tridecafluoro-2-trifluoromethylheptan-3-one (CF3CF2CF2CF2C(O)CF(CF3)2), perfluorobutane (FC-3-1-10), hydrochlorofluorocarbon admixtures (HCFC-123, HCFC-22, HCFC-124), chlorotetrafluoroethane (HCFC-124), pentafluoroethane (HFC-125), heptafluoropropane (HFC-227ea), trifluoromethane (HFC-23), hexafluoropropane (HFC-236fa), trifluoroiodide (FIC-13I1), a non-flammable / inert gas mixture (e.g., N2, Ar, CO2) and dodecafluoro-2-methylpentan-3-one (FK-5-1-12) or a combination thereof.

[0035] In one embodiment, an example of the fire extinguishing agent may include 3M's fluorine-based Novec solution.

[0036] In another embodiment, the extinguishing agent may be a dispersant, a flame retardant (phosphorus-based, melamine-based), an alkane hydrocarbon (paraffin), a wax, a fluorinated polymer or an organic solution in which a fluorinated polymer is partially dissolved, various forms of oxides, ceramics, or a combination thereof. The above fluorinated polymer may be polytetrafluoroethylene (PTFE), fluoroethylene propylene (FEP), perfluoroalkoxy resin (PFA), polyvinyl fluoride (PVF), polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), polyethylene-co-tetrafluoroethylene (ETFE), hydroxypropylene oxide (HFPO), an amorphous fluorinated polymer (e.g., product names: CYTOP, Teflon AF, Hyflon, Nafion), various resins in which a fluorinated chain is bonded to a non-fluorinated alkyne (fluorinated acrylic resin, fluorinated amide, fluorinated silicone, etc.), or a combination thereof.

[0037] The solvent may include isobutyryl isobutyrate, xylene, toluene, benzene, hexane, N-methyl pyrrolidone, acetone, N,N-dimethyl formamide or a combination thereof.

[0038] The nonwoven fabric made of nanofibers including the above-described fire extinguishing agent core and polymer shell can improve the safety of the battery by forming a film with the fire extinguishing agent released when the nonwoven polymer shell collapses, as the fire extinguishing agent has excellent affinity with lithium and reacts with lithium remaining in the solid electrolyte that may cause a polymer electrical short circuit, or by forming a film on the surfaces of the negative electrode and the positive electrode to prevent physical reaction with lithium. Alternatively, the fire extinguishing agent has a high reactivity with the solid electrolyte and can change the structure of the solid electrolyte, thereby reducing ionic conductivity, thereby suppressing the battery reaction and improving safety. In one embodiment, the content of the nonwoven fabric may be 5 wt% to 10 wt%, may be 6 wt% to 10 wt%, or may be 6 wt% to 9 wt%, based on 100 wt% of the total solid electrolyte layer.

[0039] When a nonwoven fabric composed of nanofibers including the above-described extinguishing agent core and a polymer shell having the above-described specific melting point (Tm) is included in a solid electrolyte in an amount within the above range, the desired effect can be sufficiently achieved. Even if the nonwoven fabric is composed of the above-described nanofibers, if the amount is less than the above-described range, the amount of the extinguishing agent core may not be sufficient to perform the intended function, and if the amount is greater than the above-described range, it may become a factor that increases the resistance of the solid electrolyte layer, thereby deteriorating battery performance.

[0040] In one embodiment, the thickness of the polymer shell constituting the nanofiber may be 50 nm to 2 μm, or may be 100 nm to 1 μm. When the thickness of the polymer shell is within the above range, the polymer shell can more sufficiently maintain its shape before melting, while also being more easily melted at an abnormal temperature.

[0041] In one embodiment, the weight ratio of the fire extinguishing agent core and the polymer shell in the nonwoven fabric may be from 6:4 to 9:1, or may be from 7:3 to 9:1. When the weight ratio of the fire extinguishing agent core and the polymer shell is within the above range, the polymer shell can sufficiently maintain its shape before melting, while having an amount that can effectively function when melted and the fire extinguishing agent core is eluted.

[0042] Additionally, the average diameter of the nanofibers may be 5 µm to 10 µm, or 7 µm to 10 µm. When the average diameter of the nanofibers is within the above range, the solid electrolyte layer may be able to contain a more sufficient amount of the extinguishing agent while maintaining its resistance.

[0043] In an all-solid-state battery, the nonwoven fabric is filled with a solid electrolyte as described above, and includes pores to enable the solid electrolyte to be filled. The porosity of a nonwoven fabric made of such nanofibers is suitably between 50% and 99%. The porosity of a nonwoven fabric filled with a solid electrolyte having this porosity may be between 0% and 10%.

[0044] When the porosity of the nonwoven fabric is within the above range, the solid electrolyte particles can be easily filled in a sufficient amount within the nonwoven fabric, so that the nonwoven fabric fibers do not significantly act as resistance and do not interfere with maintaining the interface between the solid electrolytes, which is appropriate. In one embodiment, the pore size formed in the nonwoven fabric made of nanofibers may be 1 μm to 5 μm, and may also be 10 μm to 30 μm. When the pore size formed in the nonwoven fabric made of nanofibers is within the above range, the solid electrolyte can be filled in a sufficient amount within the nonwoven fabric, which is appropriate. In this way, the nonwoven fabric according to one embodiment preferably has a high porosity of 50% to 99% and a pore size of 1 μm to 30 μm.

[0045] In addition, the solid electrolyte layer of the all-solid-state battery is formed by filling a very small amount of solid electrolyte inside a non-woven fabric having pores, and solid electrolyte particles are sintered thereon, so the non-woven fabric actually acts as a mesh structure that forms the skeleton of the solid electrolyte.

[0046] Porous gases, which are generally used as solid electrolytes or separators in lithium ion secondary batteries, are used for the purpose of preventing internal short circuits and at the same time impregnating liquid electrolytes for ion transport. Even if pores are formed, the pore size is very small, for example, pores of several tens of nm are formed.

[0047] Accordingly, since it is not easy to impregnate a solid electrolyte into a porous substrate used in a lithium ion secondary battery, it is not easy to apply the porous substrate to an all-solid-state battery according to one embodiment.

[0048] In one embodiment, the solid electrolyte layer may further include a solid electrolyte coating layer formed on the nonwoven fabric.

[0049] When the solid electrolyte according to one embodiment further includes a solid electrolyte coating layer, the solid electrolyte layer may be positioned in contact with the anode or may be positioned in contact with the cathode. The position of the solid electrolyte layer may be appropriately adjusted depending on the type of extinguishing agent.

[0050] The above solid electrolyte coating layer may have a thickness of about 10% to 20% of the total thickness of the solid electrolyte layer.

[0051] The solid electrolyte filled in the above nonwoven fabric and the solid electrolyte included in the solid electrolyte coating layer may be the same.

[0052] The above solid electrolyte may be an inorganic solid electrolyte such as a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a halide-based solid electrolyte, or a solid polymer electrolyte.

[0053] The above sulfide-based solid electrolyte is Li2S-P2S5, Li2S-P2S5-LiX (X is a halogen element, for example, I or Cl), Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z m S n (m and n are integers greater than or equal to 0 and less than or equal to 12, respectively, and Z is one of Ge, Zn, or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q (p and q are integers greater than or equal to 0 and less than or equal to 12, respectively; M is one of P, Si, Ge, B, Al, Ga In), Li a M b P c S d A e (a, b, c, d, and e are each integers greater than or equal to 0 and less than or equal to 12, M is Ge, Sn, Si, or a combination thereof, and A is one of F, Cl, Br, or I). Li 7-x PS 6-x F x (0≤x≤2), Li 7-x PS 6-x Cl x (0≤x≤2), Li 7-x PS 6-x Br x (0≤x≤2) or Li 7-x PS 6-x I x (0≤x≤2) can be. Also, specifically, Li3PS4, Li7P3S 11 , Li7PS6, Li6PS5Cl, Li6PS5Cl, Li6PS5I, Li6PS5Br, Li 5.8 PS 4.8 Cl 1.2 , Li 6.2 PS5.2 Br 0.8 It could be the back.

[0054] In one embodiment, the sulfide-based solid electrolyte may be an argyrodite-type sulfide-based solid electrolyte. The argyrodite-type sulfide-based solid electrolyte may be, for example, Li a M b P c S d A e (a, b, c, d and e are all 0 or more and 12 or less, M is Ge, Sn, Si or a combination thereof, and A is one of F, Cl, Br, or I), and specifically Li3PS4, Li7P3S 11 , Li7PS6, Li6PS5Cl, Li6PS5Br, Li6PS5I, Li 5.8 PS 4.8 Cl 1.2 , Li 6.2 PS 5.2 Br 0.8 It could be the back.

[0055] The sulfide-based solid electrolyte may be amorphous, crystalline, or a mixture thereof. For example, the sulfide-based solid electrolyte may be obtained by mixing Li2S and P2S5 in a molar ratio of 50:50 to 90:10, or 50:50 to 80:20. Within the above mixing ratio range, a sulfide-based solid electrolyte having excellent ionic conductivity can be manufactured. The ionic conductivity can be further improved by further including other components such as SiS2, GeS2, and B2S3. Mechanical milling or a solution method can be applied as a mixing method. Mechanical milling is a method in which starting materials are placed in a reactor and vigorously stirred with a ball mill, etc. to pulverize the starting materials and mix them. When the solution method is used, the starting materials are mixed in a solvent to obtain a solid electrolyte as a precipitate. In addition, additional calcination can be performed after mixing. If additional calcination is performed, the crystals of the solid electrolyte can become more solid.

[0056] Of course, a commercially available solid electrolyte can be used as the sulfide-based solid electrolyte.

[0057] The above oxide-based solid electrolyte is, for example, Li 1+x Ti 2-x Al(PO4)3(LTAP)(0≤x≤4), Li 1+x+y Al x Ti 2-x Si y P 3-y O 12 (0 <x<2, 0≤y<3), BaTiO3, Pb(Zr,Ti)O3(PZT), Pb 1-x La x Zr 1-y Ti y O3(PLZT)(0≤x<1, 0≤y<1), Pb(Mg3Nb 2 / 3 )O3-PbTiO3(PMN-PT), HfO2, SrTiO3, SnO2, CeO2, Na2O, MgO, NiO, CaO, BaO, ZnO, ZrO2, Y2O3, Al2O3, TiO2, SiO2, lithium phosphate (Li3PO4), lithium titanium phosphate (Li x Ti y (PO4)3, 0 <x<2, 0<y<3), Li 1+x+y (Al, Ga) x (Ti, Ge) 2-x Si y P 3-y O 12 (0≤x≤1, 0≤y≤1), lithium lanthanum titanate (Li x La y TiO3, 0 <x<2, 0<y<3), Li2O, LiAlO2, Li2O-Al2O3-SiO2-P2O5-TiO2-GeO2계 세라믹스, 가넷(Garnet)계 세라믹스 Li 3+x La3M2O 12 (M= Te, Nb, or Zr, x is an integer from 1 to 10), or a mixture thereof.

[0058] The above solid polymer electrolytes include, for example, polyethylene oxide, poly(diallyldimethylammonium)trifluoromethanesulfonyl imide (poly(diallyldimethylammonium)TFSI), Cu3N, Li3N, LiPON, and Li3PO. 4· Li2S · SiS2, Li2S · GeS 2· Ga2S3, Li2O · 11Al2O3, Na2O · 11Al2O3, (Na,Li) 1+x Ti 2-x Al x (PO4)3(0.1≤x≤0.9), Li 1+x Hf 2-x Al x (PO4)3(0.1≤x≤0.9), Na3Zr2Si2PO 12 , Li3Zr2Si2PO 12 , Na5ZrP3O 12 , Na5TiP3O 12 , Na3Fe2P3O 12 , Na4NbP3O 12 , Na-Silicates, Li 0.3 La 0.5 TiO3, Na5MSi4O 12 (M is a rare earth element such as Nd, Gd, Dy) Li5ZrP3O 12 , Li5TiP3O 12 , Li3Fe2P3O 12 , Li4NbP3O 12 , Li 1+x (M,Al,Ga) x (Ge 1-y Ti y ) 2-x (PO4)3(0≤x≤0.8, 0≤y≤1.0, M is Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm or Yb), Li 1+x+y Q x Ti 2-x Si y P 3-y O 12(0 <x≤0.4, 0<y≤0.6, Q 는 Al 또는 Ga), Li6BaLa2Ta2O 12 , Li7La3Zr2O 12 , Li5La3Nb2O 12 , Li5La3M2O 12 (M is Nb, Ta) and Li 7+x A x La 3-x Zr2O 12 (0 <x<3, A는 Zn) 중에서 선택된 하나 이상을 포함할 수 있다..

[0059] The above halide-based solid electrolyte may include a Li element, an M element (M is a metal other than Li), and an X element (X is a halogen). As X, for example, F, Cl, Br, and I may be mentioned. In particular, in the halide-based solid electrolyte, at least one of Br and Cl is suitable as X. In addition, as the M, for example, a metal element such as Sc, Y, B, Al, Ga, or In may be mentioned.

[0060] The composition of the above halide-based solid electrolyte is not particularly limited, but Li 6-3a M a Br b Cl c (In the formula, M is a metal other than Li, and 0 <a<2, 0≤b≤6, 0≤c≤6, b+c=6)로 표현될 수 있다. 이때, 상기 a는 0.75 이상일 수 있고, 1 이상일 수 있고, a는, 1.5 이하일 수 있다. 상기 b는 1 이상일 수 있고, 2 이상일 수 있다. 또한, 상기 c는, 3 이상일 수 있고, 4 이상일 수도 있다. 상기 할라이드계 고체 전해질의 구체적인 예로는 Li3YBr6, Li3YCl6또는 Li3YBr2Cl4를 들 수 있다.

[0061] The above solid electrolyte is in the form of particles, and the average particle diameter (D50) may be 5.0 ㎛ or less, for example, 0.1 ㎛ to 5.0 ㎛, 0.5 ㎛ to 5.0 ㎛, 0.5 ㎛ to 4.0 ㎛, 0.5 ㎛ to 3.0 ㎛, 0.5 ㎛ to 2.0 ㎛, or 0.5 ㎛ to 1.0 ㎛.

[0062] The above solid electrolyte layer may further include a binder. At this time, the binder may be, but is not limited to, styrene butadiene rubber, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, an acrylate polymer, or a combination thereof, and any binder used in the relevant technical field may be used. The acrylate polymer may be butyl acrylate, polyacrylate, polymethacrylate, or a combination thereof.

[0063] Nanofibers constituting a solid electrolyte according to one embodiment can be manufactured using coaxial electrospinning. For example, a solution containing a polymer having a melting point of 100°C to 180°C can be injected into an outer nozzle for coaxial electrospinning, a solution containing a fire extinguishing agent can be injected into an inner nozzle, and then a contact roller can be positioned on a target substrate, followed by applying a constant voltage. According to this spinning process, nanofibers can be manufactured in which the fire extinguishing agent is contained in the inner core and the polymer is contained in the outer shell.

[0064] The above voltage may be 5 kV to 30 kV.

[0065] In one embodiment, the pore size and porosity of the nonwoven substrate can be controlled by controlling the rotation speed and horizontal movement distance of the connecting roller. For example, the rotation speed of the connecting roller can be 100 rpm to 300 rpm, or 200 rpm to 500 rpm. Additionally, the horizontal movement distance can be 80 mm to 150 mm, or 100 mm to 200 mm.

[0066] The solution containing the polymer contains a first solvent, and the solution containing the extinguishing agent contains a second solvent, wherein the first solvent and the second solvent may be the same or different from each other. The first solvent and the second solvent may be acetone, methanol, methylcyclohexanol, methylbutyl ketone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanol, ethanol, ethyl ether, propanol, butanol, styrene, isobutyl alcohol, isopentyl alcohol, isopropyl alcohol, dimethylformamide, methylpyrrolidone, dimethylacetamide, acetonitrile, dimethyl sulfoxide, dichloromethane, octyl acetate, chloroform, tetrahydrofuran, tetrachloroethylene, diethyl ether, dioxane, pentane, hexane, cresol, benzene, chlorobenzene, xylene, toluene, or a combination thereof.

[0067] A solid electrolyte layer according to one embodiment can be manufactured using the above nanofibers.

[0068] A nonwoven fabric is manufactured using the above nanofibers. The nonwoven fabric manufacturing process can be performed separately, but the nanofibers produced during the nanofiber manufacturing process can be laminated to form a nonwoven fabric. In this case, a separate nonwoven fabric manufacturing process is not necessary.

[0069] The above nonwoven fabric may have a porosity of 50% to 90%. The nonwoven fabric is fixed to a flat plate, a solid polymer solution is coated thereon to a certain thickness, and then dried to produce a solid electrolyte layer having a porosity of 0% to 10%. In this process, the amount of the solid polymer solution may be adjusted so that the solid electrolyte is completely impregnated into the pores of the nonwoven fabric, or the pores are completely filled with the solid electrolyte, and then the solid electrolyte is coated on the nonwoven fabric to form a solid electrolyte coating layer. For example, when the solid polymer solution is applied in an amount corresponding to the porosity of the nonwoven fabric, the pores can be impregnated only into the pores of the nonwoven fabric, and when the solid polymer solution is applied in an amount equal to or greater than the porosity of the nonwoven fabric, the solid electrolyte coating layer can be formed not only within the pores of the nonwoven fabric but also within the pores.

[0070] In the above solid polymer solution, the solvent may be isobutyryl isobutyrate, xylene, toluene, benzene, hexane, or a combination thereof. Since the solid electrolyte layer formation process is widely known in the art, a detailed description thereof will be omitted herein.

[0071] An all-solid-state battery according to one embodiment further includes a cathode and an anode, and the solid electrolyte layer may be positioned between the cathode and the anode.

[0072] The above-described negative electrode may include a negative electrode coating layer and a current collector supporting the negative electrode coating layer. In one embodiment, the negative electrode coating layer refers to a layer that helps lithium ions released from the positive electrode active material during charge / discharge of an all-solid-state battery to move toward the negative electrode and be deposited on the surface of the current collector. That is, a lithium deposition layer is formed between the current collector and the negative electrode coating layer due to the deposition of lithium ions, and the lithium deposition layer functions as a negative electrode active material. Such a negative electrode is generally referred to as a deposition-type negative electrode. The metal and amorphous carbon included in the negative electrode coating layer do not function as a negative electrode active material that directly participates in the charge / discharge reaction. In one embodiment, the lithium titanium oxide particles also do not function as a negative electrode active material that directly participates in the charge / discharge reaction. Such a deposition-type negative electrode refers to a negative electrode that does not include a negative electrode active material when assembling a battery, but in which the lithium deposition layer functions as a negative electrode active material.

[0073] The carbonaceous material may be amorphous carbon, crystalline carbon, or a mixture thereof. The amorphous carbon may be, for example, carbon black, acetylene black, Denka black, Ketjen black, furnace black, activated carbon, or a combination thereof. An example of the carbon black may be Super P (Timcal). The crystalline carbon may be natural graphite, artificial graphite, carbon nanotubes, graphene, or a combination thereof. The crystalline carbon may be in the form of amorphous, plate-like, flake-like, spherical, or fiber-like particles.

[0074] In one embodiment, the carbonaceous material may be a single particle, or may be an assembly having a secondary particle form in which primary particles are assembled. When the carbonaceous material is a single particle, the size of the carbonaceous material may be a nano-size with an average particle diameter of 100 nm or less, for example, 10 nm to 100 nm.

[0075] Additionally, when the carbon-based material is an assembly, the particle size of the primary particles may be 20 nm to 100 nm, and the particle size of the secondary particles may be 1 μm to 20 μm.

[0076] In one embodiment, the particle size of the primary particles may be 20 nm or more, 30 nm or more, 40 nm or more, 50 nm or more, 60 nm or more, 70 nm or more, 80 nm or more, or 90 nm or more, and may be 100 nm or less, 90 nm or less, 80 nm or less, 70 nm or less, 60 nm or less, 50 nm or less, 40 nm or less, or 30 nm or less.

[0077] In one embodiment, the particle size of the secondary particles may be 1 µm or more, 3 µm or more, 5 µm or more, 7 µm or more, 10 µm or more, or 15 µm or more, and may be 20 µm or less, 15 µm or less, 10 µm or less, 7 µm or less, 5 µm or less, or 3 µm or less.

[0078] The shape of the primary particles may be spherical, elliptical, plate-shaped, or a combination thereof, and in one embodiment, the shape of the primary particles may be spherical, elliptical, or a combination thereof.

[0079] The above metal may be Ag, Au, Sn, Zn, Al, Mg, Ge, Cu, In, Ni, Bi, Pt, Pd or a combination thereof. As the cathode coating layer includes the above metal, the electrical conductivity of the cathode can be further improved.

[0080] The metal may be a nanoparticle, and the size of the metal nanoparticle may be, for example, an average size of 5 nm to 80 nm, but a nanometer size may be suitably used. By using the metal nanoparticle having such a nano size, the battery characteristics (e.g., life characteristics) of the all-solid-state battery can be improved. If the metal particle size increases to the micrometer level, the uniformity of the metal particles in the negative electrode coating layer decreases, so that the current density in a specific region increases and the cycle life characteristics may deteriorate, which is not suitable.

[0081] In the cathode coating layer according to one embodiment, the content of the carbon-based material and the metal may be 50 wt% to 98 wt%, 70 wt% to 95 wt%, or 70 wt% to 90 wt% with respect to 100 wt% of the total weight of the cathode coating layer.

[0082] The mixing ratio of the carbon-based material and the metal may be a weight ratio of 1:1 to 99:1. For example, the weight of the carbon-based material may be 1 or more, 2 or more, 3 or more, 4 or more, 5 or more, 10 or more, 15 or more, 20 or more, 25 or more, 30 or more, 35 or more, 40 or more, 45 or more, 50 or more, 55 or more, 60 or more, 65 or more, 70 or more, 75 or more, 80 or more, 85 or more, 90 or more or 95 or more, and may be 99 or less, 95 or less, 90 or less, 85 or less, 80 or less, 75 or less, 70 or less, 65 or less, 60 or less, 55 or less, 50 or less, 45 or less, 40 or less, 35 or less, 30 or less, 25 or less, 20 or less, 15 or less, 10 or less, 5 or less, 4 or less, 3 or less or 2 or less. For example, the weight ratio of the carbon-based material and the metal particles may be 1:1 to 5:1, 1:1 to 10:1, 1:1 to 20:1, 1:1 to 25:1, 1:1 to 30:1, 1:1 to 40:1, 1:1 to 50:1, 1:1 to 60:1, 1:1 to 70:1, 1:1 to 80:1, or 1:1 to 90:1.

[0083] The above cathode coating layer may further include a binder.

[0084] The above binder may include a non-aqueous binder, an aqueous binder, or a combination thereof.

[0085] The non-aqueous binder may include, for example, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, a polymer comprising ethylene oxide, an ethylene propylene copolymer, polystyrene, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamideimide, polyimide, polyacrylate, or a combination thereof.

[0086] The above-mentioned aqueous binder may be a rubber-based binder or a polymer resin binder. The rubber-based binder may be selected from styrene-butadiene rubber, acrylated styrene-butadiene rubber, acrylonitrile-butadiene rubber, acrylic rubber, butyl rubber, fluororubber, and combinations thereof. The above-mentioned polymer resin binder may be selected from polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, polyacrylonitrile, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, acrylic resin, phenol resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0087] The aqueous binder may include a cellulose-based compound. For example, the aqueous binder described above and the cellulose-based compound may be mixed and used, and the mixing ratio thereof may be appropriately controlled. The cellulose-based compound may include carboxymethyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, an alkali metal salt thereof, or a combination thereof. Na, K, or Li may be used as the alkali metal. The cellulose-based compound may function as a binder or as a thickener that provides viscosity. Accordingly, the content of the cellulose-based compound need not be limited, but, for example, the content of the cellulose-based compound may be 0.1 to 3 parts by weight based on 100 parts by weight of the negative electrode active material.

[0088] The above binders are not limited to these, and any binder used in the relevant technical field may be used, and their content can also be appropriately adjusted.

[0089] The binder may be present in an amount of 1 to 15 wt% based on 100 wt% of the total weight of the cathode coating layer, for example, the binder may be present in an amount of 1 wt% or more, 2 wt% or more, 3 wt% or more, 4 wt% or more, 5 wt% or more, 6 wt% or more, 7 wt% or more, 8 wt% or more, 9 wt% or more, 10 wt% or more, 11 wt% or more, 12 wt% or more, 13 wt% or more, or 14 wt% or more, and 15 wt% or less, 14 wt% or less, 13 wt% or less, 12 wt% or less, 11 wt% or less, 10 wt% or less, 9 wt% or less, 8 wt% or less, 7 wt% or less, 6 wt% or less, 5 wt% or less, 4 wt% or less, 3 wt% or less, or 2 wt% or less based on 100 wt% of the total weight of the cathode coating layer.

[0090] The above-described negative electrode coating layer may further include additives used in the negative electrode of an all-solid-state battery, such as fillers, dispersants, and ionic conductive agents. As fillers, dispersants, and ionic conductive agents that can be included in the negative electrode coating layer, known materials generally used in all-solid-state batteries may be used.

[0091] The thickness of the cathode coating layer may be 1 µm to 20 µm. For example, the thickness of the cathode coating layer may be 1 µm or more, 3 µm or more, 5 µm or more, 20 µm or less, 18 µm or less, 16 µm or less, 14 µm or less, 12 µm or less, or 10 µm or less.

[0092] The current collector may be, for example, indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li) or an alloy thereof, and may be in the form of a foil or sheet. The thickness of the negative electrode current collector may be 1 μm to 20 μm, 5 μm to 15 μm, or 7 μm to 10 μm.

[0093] The current collector may be formed of the metal as a substrate and may further include a thin film formed on the substrate. The thin film may include an element capable of forming an alloy with lithium, and may be, for example, gold, silver, zinc, tin, indium, silicon, aluminum, bismuth, or a combination thereof, but is not limited thereto, and any element capable of forming an alloy with lithium in the art may be used. When the current collector further includes a thin film, when the lithium-containing layer is formed by precipitation during charging, a more planarized lithium-containing layer may be formed, thereby further improving the cycle life of the all-solid-state battery.

[0094] The thickness of the above thin film may be 1 nm to 800 nm, 10 nm to 700 nm, 50 nm to 600 nm, or 100 nm to 500 nm. When the thin film thickness is within the above range, the cycle life characteristics can be further improved.

[0095] According to one embodiment, the negative electrode may further include a lithium-containing layer formed during initial charging after battery manufacturing, between the current collector and the negative electrode coating layer. The thickness of the lithium-containing layer may be 1 µm to 1000 µm, 1 µm to 500 µm, 1 µm to 200 µm, 1 µm to 150 µm, 1 µm to 100 µm, or 1 µm to 50 µm. When the thickness of the lithium-containing layer is within the above range, the lithium storage function may be appropriately performed, and there may be an advantage of further improving the lifespan.

[0096] The lithium-containing layer can be formed when lithium ions are released from the positive electrode active material during charging after the battery is manufactured, pass through the solid electrolyte, and move toward the negative electrode, resulting in lithium being precipitated and deposited on the negative electrode current collector.

[0097] The above charging process may be a chemical reaction process performed once to three times at 0.05C to 1C at about 25°C to 50°C. When lithium is precipitated and deposited to form a lithium-containing layer, the lithium contained in the lithium-containing layer is ionized and moves toward the positive electrode during discharge, so that the lithium can be used as an anode active material.

[0098] In one embodiment, since the lithium-containing layer is positioned between the current collector and the negative electrode coating layer, the negative electrode coating layer can serve as a protective layer for the lithium-containing layer, thereby inhibiting the precipitation and growth of lithium dendrites. This can suppress short-circuiting and capacity degradation of the all-solid-state battery, and consequently improve the cycle life of the all-solid-state battery.

[0099] The above positive electrode includes a positive electrode current collector and a positive electrode active material layer positioned on one surface of the positive electrode current collector.

[0100] The above-mentioned positive electrode active material layer may include a positive electrode active material. The positive electrode active material may be a positive electrode active material capable of reversibly absorbing and releasing lithium ions. For example, the positive electrode active material may use at least one of a composite oxide of lithium and a metal selected from cobalt, manganese, nickel, and combinations thereof. Specific examples of the positive electrode active material include Li a A 1-b B 1 b D 1 2(0.90≤a≤1.8, 0≤b≤0.5); Li a E 1-b B 1 b O 2-c D 1 c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5); Li a E 2-b B 1 b O 4-c D 1 c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤05); Lia Ni 1-b-c Co b B 1 c D 1 α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α≤2); Li a Ni 1-b-c Co b B 1 c O 2-α F 1 α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni 1-b-c Co b B 1 c O 2-α F 1 2(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni 1-b-c Mr b B 1 c D 1 α (0.90≤≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α≤2); Li a Ni 1-b-c Mr b B 1 c O 2-α F 1 α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni 1-b-c Mr b B 1 c O 2-α F 1 2(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni b HAVE BEEN c G d O2(0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0.001≤d≤0.1); Li a Ni b Coc L 1 d G e O2(0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0≤e≤0.1); Li a NiG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a CoG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a MnG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn2G b O4(0.90≤a≤1.8, 0.001≤b≤0.1); QO2; QS2; LiQS2; V2O5; LiV2O5; LiI 1 O2; LiNiVO4; Li (3-f) J2(PO4)3(0 ≤ f ≤ 2); Li (3-f) Fe2(PO4)3(0 ≤ f ≤ 2); or LiFePO4.

[0101] In the above chemical formula, A is Ni, Co, Mn, or a combination thereof; B 1 is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements or a combination thereof; D 1 is O, F, S, P, or a combination thereof; E is Co, Mn, or a combination thereof; F 1 is F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; Q is Ti, Mo, Mn, or a combination thereof; I 1 is Cr, V, Fe, Sc, Y, or a combination thereof; J is V, Cr, Mn, Co, Ni, Cu, or a combination thereof; L 1 is Mn, Al or a combination thereof.

[0102] According to one implementation example, LiNi is used as the positive electrode active material. xCo y Al z O2(NCA), LiNi x Co y Mn z O2(NCM)(but, 0 <x<1, 0<y<1, 0<z<1, x+y+z=1) 등의 삼성분계 리튬 전이 금속 산화물을 들 수 있다.

[0103] Of course, it is also possible to use a compound having a coating layer on the surface of the compound, or it is also possible to use a mixture of the compound and a compound having a coating layer. The coating layer may include at least one coating element compound selected from the group consisting of an oxide of the coating element, a hydroxide of the coating element, an oxyhydroxide of the coating element, an oxycarbonate of the coating element, and a hydroxycarbonate of the coating element. The compounds forming these coating layers may be amorphous or crystalline. The coating elements included in the coating layer may include Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, or mixtures thereof. The coating layer forming process may use any coating method as long as it can coat the compound with these elements in a method that does not adversely affect the properties of the positive electrode active material (for example, spray coating, dipping, etc.), and since this is well understood by those working in the relevant field, a detailed description thereof will be omitted.

[0104] In addition, as the above coating layer, any known coating layer of the positive electrode active material of an all-solid-state battery can be applied, and examples thereof include Li2O-ZrO2 (LZO).

[0105] Furthermore, when the cathode active material is a ternary compound containing nickel, cobalt, and manganese, or nickel, cobalt, and aluminum, the capacity density of the all-solid-state battery can be further improved and metal dissolution from the cathode active material can be further reduced in a charged state. Consequently, the all-solid-state battery can exhibit improved long-term reliability and cycle performance in a charged state.

[0106] Here, examples of the shape of the positive electrode active material include spherical, elliptical, and other particle shapes. Furthermore, the average particle diameter of the positive electrode active material is not particularly limited, and may be within the range applicable to positive electrode active materials for existing all-solid-state secondary batteries. Furthermore, the content of the positive electrode active material in the positive electrode active material layer is also not particularly limited, and may be within the range applicable to positive electrode layers for existing all-solid-state secondary batteries.

[0107] The positive electrode active material layer may additionally include a solid electrolyte. The solid electrolyte included in the positive electrode active material layer may be the same as or different from the solid electrolyte included in the solid electrolyte layer. The solid electrolyte may be included in an amount of 10 wt% to 30 wt% based on the total weight of the positive electrode active material layer.

[0108] The above positive electrode current collector may include, for example, indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li) or an alloy thereof, and may be in the form of a foil or sheet.

[0109] The above positive electrode active material layer may further include a binder and / or a conductive material.

[0110] The above binder may include, but is not limited to, polymers including polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin, nylon, etc.

[0111] The binder may be included in an amount of 0.1 wt% to 5 wt%, or 0.1 wt% to 3 wt%, based on the total weight of the positive electrode active material layer. Within the above content range, the binder can sufficiently exhibit adhesive ability without deteriorating battery performance.

[0112] The above conductive material is used to provide conductivity to the electrode, and in the battery to be formed, any material that does not cause a chemical change and is electronically conductive can be used. Examples of such materials include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nano fiber, and carbon nanotube; metal-based materials containing copper, nickel, aluminum, silver, etc. and in the form of metal powder or metal fiber; conductive polymers such as polyphenylene derivatives; or conductive materials including mixtures thereof.

[0113] The conductive material may be included in an amount of 0.1 wt% to 5 wt%, or 0.1 wt% to 3 wt%, based on the total weight of the positive electrode active material layer. Within the above content range, the conductive material can improve electrical conductivity without degrading battery performance.

[0114] The thickness of the positive electrode active material layer may be 90 μm to 200 μm. For example, the thickness of the positive electrode active material layer may be 90 μm or more, 100 μm or more, 110 μm or more, 120 μm or more, 130 μm or more, 140 μm or more, 150 μm or more, 160 μm or more, 170 μm or more, 180 μm or more, or 190 μm or more, and may be 200 μm or less, 190 μm or less, 180 μm or less, 170 μm or less, 160 μm or less, 150 μm or less, 140 μm or less, 130 μm or less, 120 μm or less, or 110 μm or less.

[0115] In one embodiment, the all-solid-state battery may further include a buffer material to cushion changes in thickness that occur during charging and discharging. The buffer material may be positioned between the negative electrode and the case, and in the case of a battery in which one or more electrode assemblies are stacked, the buffer material may be positioned between different electrode assemblies.

[0116] The above-mentioned cushioning material may be a material having an elastic recovery rate of 50% or more and an insulating function, and specifically, may be silicone rubber, acrylic rubber, fluorine rubber, nylon, synthetic rubber, or a combination thereof. The above-mentioned cushioning material may be in the form of a polymer sheet.

[0117] FIG. 2 is a cross-sectional view of an all-solid-state battery according to an embodiment. Referring to FIG. 2, the all-solid-state battery (100) may have a structure in which an electrode assembly in which a negative electrode (400) including a negative electrode collector (401) and a negative electrode coating layer (403), a solid electrolyte layer (300), and a positive electrode (200) including a positive electrode active material layer (203) and a positive electrode collector (201) are laminated is housed in a case such as a pouch. The all-solid-state battery (100) may further include an elastic layer (500) on the outer side of at least one of the positive electrode (200) and the negative electrode (400). Although FIG. 2 illustrates one electrode assembly including the negative electrode (400), the solid electrolyte layer (300), and the positive electrode (200), an all-solid-state battery may be manufactured by laminating two or more electrode assemblies.

[0118] Fig. 3 schematically illustrates an all-solid-state battery according to another embodiment. The all-solid-state battery (100) illustrated in Fig. 3 includes a positive electrode (200) including a positive electrode current collector (201) and a positive electrode active material layer (203), a negative electrode (400) including a negative electrode current collector (401), a negative electrode coating layer (403), and a solid electrolyte (300) positioned between the positive electrode (200) and the negative electrode (400), and includes a battery case (500) in which these are housed, and further includes a lithium precipitation layer (405') between the negative electrode current collector (401) and the negative electrode coating layer (403). When the all-solid-state battery is charged, the lithium precipitation layer can be formed by lithium ions being released from the positive electrode active material and deposited on the negative electrode current collector (401').

[0119] An all-solid-state battery according to one embodiment can be manufactured by a step of preparing a laminate by positioning a cathode, an anode, and a solid electrolyte layer between the cathode and the anode, and pressing the laminate.

[0120] The pressurizing process can be performed at a temperature ranging from 25°C to 90°C. In addition, the pressurizing process can be performed by pressurizing at a pressure of 550 MPa or less, for example, 500 MPa or less, for example, 1 MPa to 500 MPa. The pressurizing time can vary depending on the temperature and pressure, and can be, for example, less than 30 minutes. The pressurizing process can be, for example, isostatic pressing, roll pressing, plate pressing, or warm isostatic pressing. The porosity of the solid electrolyte layer in the all-solid-state battery manufactured according to this process can be 0% to 10%.

[0121] Hereinafter, examples and comparative examples of the present invention will be described. However, the following examples are merely examples of the present invention, and the present invention is not limited to the following examples.

[0122] (Example 1)

[0123] (1) Manufacturing of solid electrolyte layer

[0124] A solution containing a polyethylene polymer having a melting point of 180°C and an organic solvent of methanol in a weight ratio of 1:9 was injected into the outer nozzle for coaxial electrospinning, and a solution containing a 1,1,1,2,2-pentafluoroethane fire extinguishing agent and an organic solvent of ethanol in a weight ratio of 1:9 was injected into the inner nozzle. After positioning a contact roller on the target substrate, a voltage of 10 kV was applied, thereby producing nanofibers having an average diameter of 20 μm. The produced nanofibers contained the fire extinguishing agent core and the polymer shell in a weight ratio of 7:3, and the thickness of the polymer shell was 1 μm.

[0125] In the above nanofiber manufacturing process, a lamination process of nanofibers also occurred simultaneously, resulting in the manufacture of a nonwoven fabric having a porosity of 70% and a pore size (D50) of 10 μm. An isobutyl isobutylate solid polymer solution (solid content: 50 wt%) containing an argyrodite-type solid electrolyte Li6PS5Cl was coated on the nonwoven fabric, thereby manufacturing a solid electrolyte layer having a porosity of 5%, a 100 μm thick nonwoven fabric, and a 150 μm thick solid electrolyte coating layer on the nonwoven fabric. At this time, the content of the nonwoven fabric was 10 wt% with respect to the total 100 wt% of the solid electrolyte layer.

[0126] (2) Manufacturing of cathode

[0127] A cathode coating layer slurry was prepared by mixing Ag nanoparticles (D50: 60 nm) and carbon black in a weight ratio of 10:90 in a water solvent. The carbon black was a mixture of single particles with a particle diameter of 38 nm and secondary particles, and the secondary particles were assembled from primary particles with a particle diameter of 76 nm and secondary particles with a particle diameter of 275 nm.

[0128] After coating the above slurry on a stainless steel foil current collector, vacuum drying was performed at 80°C to manufacture a negative electrode including a 12 μm thick negative electrode coating layer and a 10 μm thick current collector.

[0129] (3) Manufacturing of anode

[0130] LZO (Li-doped zinc oxide) coated cathode active material (LiNi 0.9 Mn 0.05 Co 0.05 A mixture was prepared by mixing O2), argyrodite-type solid electrolyte Li6PS5Cl, conductive carbon nanofibers, and binder polytetrafluoroethylene in a weight ratio of 85:15:3:1.5.

[0131] The prepared mixture was coated on an aluminum foil current collector and then vacuum-dried at 45°C to prepare a negative electrode including a 160 μm thick positive active material layer and a 10 μm thick current collector.

[0132] (4) Manufacturing of all-solid-state full cells

[0133] The manufactured negative electrode, solid electrolyte layer, and positive electrode were sequentially laminated, and a pressure of 500 MPa was applied to manufacture an all-solid-state battery.

[0134] When the all-solid-state battery manufactured according to Example 1 was charged and discharged and reached 100°C, battery operation ceased. This demonstrates excellent safety.

[0135] Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications can be made within the scope of the patent claims, the detailed description of the invention, and the attached drawings, and it is obvious that this also falls within the scope of the present invention.

Claims

1. An all-solid-state battery comprising a nonwoven fabric made of nanofibers and a solid electrolyte layer including a solid electrolyte filled in the nonwoven fabric, The above nanofibers include a digestive core and a polymer shell having a melting point (Tm) of 100°C to 180°C, An all-solid-state battery wherein the content of the non-woven fabric is 5 to 10 wt% with respect to 100 wt% of the entire solid electrolyte layer.

2. In paragraph 1, The above extinguishing agent is 1,1,1,2,2-pentafluoroethane (CF) 3 CF 2 H, HFC-125), 1,1,1,2,3,3,3-Heptafluoropropane (CF) 3 CHFCF 3 ), Chlorotetrafluoroethane (CHClFCF) 3 ), dodecafluoro-2-methylpentan-3-one (dodecafluoro-2-methylpentan-3-one (FK-5-1-12, CF 3 CF 2 C(O)CF(CF 3 ) 2 )), 1-chloro-1,2,2,2-tetrafluoroethane (1-chloro-1,2,2,2-tetrafluoroethane, C 2 HClF 4 , 2-chloro-1,1,1,2-tetrafluoroethane (2-chloro-1,1,1,2-tetrafluoroethane, (CHClFCF 3 , HCFC-124), decafluorocyclohexanone (perfluorocyclohexanone), 1,1,1,2,4,4,5,5,5-nonafluoro-2-trifluoromethyl-butan-3-one (CF 3 CF 2 C(O)CF(CF 3 ) 2 (),1,1,1,2,4,5,5,5,6,6,6-octafluoro-2,4,-bis(trifluoromethyl)pentan-3-one(CF 3 ) 2 CFC(O)CF(CF 3 ) 2 ), CF 3 CF 2 C(O)CF 2 CF 2 CF 3 , CF 3 C(O)CF(CF 3 ) 2 , 1,1,1,3,3,4,4,5,5,6,6,7,7,8,8,8-hexadodecafluorooctan-2-one (CF 3 CF 2 CF 2 CF 2 CF 2 CF 2 C(O)CF 3 ), 1,1,1,3,4,4,4-heptafluoro-3-trifluoromethylbutan-2-one (CF 3 C(O)CF(CF 3 ) 2 ), 1,1,1,2,4,4,5,5-octafluoro-2-trifluoromethylpentan-3-one (HCF 2 CF 2 C(O)CF(CF 3 ) 2 ), 1,1,1,2,4,4,5,5,6,6,6-undecafluoro-2-trifluoromethylhexan-3-one (CF 3 CF 2 CF 2 C(O)CF(CF 3 ) 2 ), 1-chloro-,1,1,3,4,4,4-hexafluoro-3-trifluoromethyl-butan-2-one((CF 3 ) 2 CFC(O)CF 2 Cl), 1,1,1,2,2,4,4,5,5,6,6,6-dodecafluorohexan-3-one (CF 3 CF 2 C(O)CF 2 CF 2 CF 3 ), 1,1,1,5,5,5-hexafluoropentane-2-4-dione (CF 3 C(O)CH 2 C(O)CF 3 ), 1,1,1,2,5,6,6,6-octafluoro-2,5-bis(trifluoromethyl)hexane-3,4-dione ((CF 3 ) 2 CFC(O)C(O)C(O)CF(CF 3 ) 2 ), 1,1,1,2,2,3,3,5,5,6,6,7,7,7-tetradecafluoroheptan-4-one (CF 3 CF 2 CF 2 C(O)CF 2 CF 2 CF 3 ), 1,1,1,3,3,4,4,4-octafluorobutal-2-one (CF3C(O)CF 2 CF 3 ), 1,1,2,2,4,5,5,5-octafluoro-1-trifluoromethoxy-4-trifluoromethylpentan-3-one (CF 3 OCF 2 CF 2 C(O)CF(CF 3 ) 2 ), 1,1,1,2,4,4,5,5,6,6,7,7,7-tridecafluoro-2-trifluoromethylheptan-3-one (CF 3 CF 2 CF 2 CF 2 C(O)CF(CF 3 ) 2 ), perfluorobutane (FC-3-1-10), hydrochlorofluorocarbon admixtures (HCFC-123, HCFC-22, HCFC-124), chlorotetrafluoroethane (HCFC-124), pentafluoroethane (HFC-125), heptafluoropropane (HFC-227ea), trifluoromethane (HFC-23), hexafluoropropane (HFC-236fa), trifluoroiodide (FIC-13I1), nonflammable / inert gas mixtures (e.g. N 2 , Ar, CO 2 ) and dodecafluoro-2-methylpentan-3-one (FK-5-1-12) or a combination thereof.

3. In paragraph 1, An all-solid-state battery wherein the polymer is polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polyvinyl halide, polyester, polyamide, polyurethane, polymethyl methacrylate, polystyrene, melamine, polyvinyl alcohol, nylon or a combination thereof.

4. In paragraph 1, An all-solid-state battery having a polymer shell having a thickness of 50 nm to 2 μm.

5. In paragraph 1, An all-solid-state battery wherein the weight ratio of the digestive agent core and the polymer shell is 7:3 to 9:

1.

6. In paragraph 1, An all-solid-state battery having a porosity of the above nonwoven fabric of 50% to 99%.

7. In paragraph 1, An all-solid-state battery wherein the porosity of the solid electrolyte layer is 0% to 10%.

8. In paragraph 1, An all-solid-state battery, wherein the solid electrolyte layer further includes a solid electrolyte coating layer formed on the non-woven fabric.

9. In paragraph 1, The all-solid-state battery further includes a negative electrode including a metal and carbon-based material, and a positive electrode including a positive electrode active material, and the solid electrolyte layer is positioned between the negative electrode and the positive electrode.

10. In paragraph 9, An all-solid-state battery wherein the metal is Ag, Au, Sn, Zn, Al, Mg, Ge, Cu, In, Ni, Bi, Pt, Pd or a combination thereof.

11. In paragraph 9, An all-solid-state battery wherein the carbon-based material is amorphous carbon, crystalline carbon or a combination thereof.

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