Lithium secondary battery

Abstract

Provided is a lithium secondary battery comprising: a positive electrode comprising lithium sulfur (Li2S); a negative electrode; an electrolyte layer disposed between the positive electrode and the negative electrode; and a metal-organic framework.

Description

lithium secondary battery

[0001] It relates to a lithium secondary battery including a metal organic framework.

[0002] Recent industrial demands have led to the active development of batteries with high energy density and safety. For example, lithium secondary batteries are used in a variety of applications, including information technology, communication devices, and automobiles. Because automobiles are life-threatening, safety is also crucial.

[0003] Lithium secondary batteries using liquid electrolytes may have an increased risk of fire and / or explosion in the event of a short circuit. Solid-state secondary batteries using solid electrolytes instead of liquid electrolytes are being proposed. Solid electrolytes are less likely to catch fire than liquid electrolytes.

[0004] Solid-state secondary batteries can reduce the risk of fire or explosion by using solid electrolytes instead of liquid electrolytes. Solid-state batteries can also offer improved safety.

[0005] One aspect is to provide a lithium secondary battery with reduced hydrogen sulfide generation.

[0006] According to the implementation example

[0007] A cathode comprising lithium sulfur (Li2S); anode;

[0008] An electrolyte layer disposed between the anode and the cathode; and

[0009] A lithium secondary battery comprising a metal-organic framework is provided.

[0010] According to one aspect, the lithium secondary battery can reduce the external exposure amount of hydrogen sulfide compared to when lithium sulfur contained in the positive electrode is used alone by internally absorbing hydrogen sulfide that may be generated when the lithium sulfur contained in the positive electrode is exposed to air, by including a metal organic framework.

[0011] Figure 1 is a cross-sectional view of a lithium secondary battery according to an exemplary embodiment.

[0012] Figure 2 is a cross-sectional view of a lithium secondary battery according to an exemplary embodiment.

[0013] Figure 3 is a cross-sectional view of a lithium secondary battery according to an exemplary embodiment.

[0014] Figure 4 is a cross-sectional view of a lithium secondary battery according to an exemplary embodiment.

[0015] Figure 5 is a cross-sectional view of a lithium secondary battery according to an exemplary embodiment.

[0016] Unless otherwise defined, all terms (including technical and scientific terms) used in this disclosure have the same meaning as commonly understood by those of ordinary skill in the art to which this disclosure pertains. Furthermore, terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning within the context of the relevant technology and this disclosure, and should not be interpreted in an idealized or overly formal sense.

[0017] Exemplary embodiments are described in this disclosure with reference to cross-sectional drawings that are schematic representations of idealized embodiments. As such, variations from the shapes depicted are to be expected, for example, as a result of manufacturing techniques and / or tolerances. Therefore, the embodiments described in this disclosure should not be construed as limited to the specific shapes of regions as depicted in this disclosure, but should encompass variations in shapes resulting from, for example, manufacturing. For example, regions depicted or described as flat may typically have rough and / or non-linear features. Moreover, angles depicted as sharp may be rounded. Therefore, the regions depicted in the drawings are schematic in nature, and their shapes are not intended to depict the precise shapes of the regions, nor are they intended to limit the scope of the claims.

[0018] This creative idea may be embodied in many different forms and should not be construed as limited to the embodiments described in this disclosure. These embodiments are provided so that this disclosure will be thorough and complete, and so that it will fully convey the scope of the creative idea to those skilled in the art. Like reference numerals in the drawings indicate like elements.

[0019] When a component is referred to as being "on" another component, it can be understood that it is either directly on top of the other component or that other components may be intervening between them. Conversely, when a component is referred to as being "directly on" another component, no intervening components are present.

[0020] Although terms such as "first," "second," "third," etc. may be used herein to describe various components, elements, regions, layers, and / or zones, these components, elements, regions, layers, and / or zones should not be limited by these terms. These terms are only used to distinguish one component, element, region, layer, or zone from another component, element, region, layer, or zone. Thus, a first component, element, region, layer, or zone described below may be referred to as a second component, element, region, layer, or zone without departing from the teachings of this disclosure.

[0021] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms including "at least one," unless the content clearly dictates otherwise. "At least one" should not be construed as limiting to the singular. As used herein, the term "and / or" includes any and all combinations of one or more of the listed items. The terms "comprises" and / or "comprising" as used in the detailed description specify the presence of stated features, regions, integers, steps, operations, components, and / or ingredients, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, components, ingredients, and / or groups thereof.

[0022] Spatially relative terms such as "below," "under," "lower," "above," "upper," and the like may be used herein to readily describe the relationship of one component or feature to another. It will be understood that spatially relative terms are intended to encompass different orientations of the device when in use or operation in addition to the orientations depicted in the drawings. For example, if the device in the drawings were turned over, a component described as "below" or "below" another component or feature would then be oriented "above" the other component or feature. Thus, the exemplary term "below" can encompass both the above and below orientations. The device may be arranged in other orientations (rotated 90 degrees or otherwise rotated), and the spatially relative terms used herein may be interpreted accordingly.

[0023] "Group" means a group in the periodic table of elements according to the International Union of Pure and Applied Chemistry ("IUPAC") Group 1-18 classification system.

[0024] In the present disclosure, "particle size" or "particle diameter" refers to the average diameter when the particles are spherical, and refers to the average major axis length when the particles are non-spherical. The particle diameter can be measured using a particle size analyzer (PSA). The "particle size" or "particle diameter" refers to, for example, the average particle diameter. The "average particle diameter" refers to, for example, the median particle diameter, D50.

[0025] D50 is the size of the particle corresponding to 50% of the cumulative volume, calculated from the particle side with a smaller particle size in the particle size distribution measured by laser diffraction.

[0026] D90 is the size of the particle corresponding to 90% of the cumulative volume, calculated from the particle side with a smaller particle size in the particle size distribution measured by laser diffraction.

[0027] D10 is the size of the particle corresponding to 10% of the cumulative volume, calculated from the particle side with a small particle size in the particle size distribution measured by laser diffraction.

[0028] In this disclosure, “metal” includes both metals and metalloids such as silicon and germanium, in their elemental or ionic states.

[0029] In this disclosure, “alloy” means a mixture of two or more metals.

[0030] In the present disclosure, “electrode active material” means an electrode material capable of undergoing lithiation and delithiation.

[0031] In the present disclosure, “composite cathode active material” means a cathode material capable of undergoing lithiation and delithiation.

[0032] In the present disclosure, “negative electrode active material” means a negative electrode material capable of undergoing lithiation and delithiation.

[0033] In the present disclosure, “lithiation” and “lithiating” mean a process of adding lithium to an electrode active material.

[0034] In the present disclosure, “delithiation” and “delithiate” mean a process of removing lithium from an electrode active material.

[0035] In this disclosure, “charging” and “charging” mean a process of providing electrochemical energy to a battery.

[0036] In this disclosure, “discharging” and “discharging” mean the process of removing electrochemical energy from a battery.

[0037] In the present disclosure, “positive electrode” and “cathode” mean an electrode at which electrochemical reduction and lithiation occur during a discharge process.

[0038] In the present disclosure, “cathode” and “anode” mean electrodes where electrochemical oxidation and delithiation occur during a discharge process.

[0039] While specific implementations have been described, alternatives, modifications, variations, improvements, and substantial equivalents that are not currently anticipated or unforeseen may occur to the applicant or those skilled in the art. Accordingly, the appended claims, as filed and as amended, are intended to encompass all such alternatives, modifications, variations, improvements, and substantial equivalents.

[0040] [Lithium secondary battery]

[0041] A lithium secondary battery according to one embodiment includes a cathode including lithium sulfur; an anode; and an electrolyte layer disposed between the cathode and the anode; and a metal-organic framework. For example, the lithium secondary battery can effectively remove hydrogen sulfide generated from lithium sulfur (Li2S) included in the cathode during a recharge / discharge cycle by including the metal-organic framework.

[0042] Fig. 1 is a cross-sectional view of a lithium secondary battery according to an exemplary embodiment. Fig. 2 is a cross-sectional view of a lithium secondary battery according to an exemplary embodiment. Fig. 3 is a cross-sectional view of a lithium secondary battery according to an exemplary embodiment. Fig. 4 is a cross-sectional view of a lithium secondary battery according to an exemplary embodiment. Fig. 5 is a cross-sectional view of a lithium secondary battery according to an exemplary embodiment.

[0043] Hereinafter, with reference to FIGS. 1 to 5, a lithium secondary battery comprising a positive electrode including lithium sulfur (Li2S); a negative electrode; an electrolyte layer disposed between the positive electrode and the negative electrode; and a metal-organic framework will be described in more detail.

[0044] [Metal-Organic Frameworks]

[0045] A lithium secondary battery (1) according to one embodiment may include a metal organic framework.

[0046] For example, the metal organic structure may be included in the anode (10); the cathode (20); the electrolyte layer (30) or the inert member (40) described below.

[0047] According to one embodiment, the metal-organic structure may be included in the lithium secondary battery (1) as a separate configuration independent from the positive electrode (10); the negative electrode (20); the electrolyte layer (30) and the inert member (40).

[0048] In this specification, lithium secondary battery (1) is used to mean a lithium secondary battery unit cell and a lithium secondary battery module, and the metal organic structure may be included inside a lithium secondary battery unit cell or a lithium secondary battery module in which a plurality of lithium secondary battery unit cells are connected.

[0049] The lithium secondary battery unit cell refers to a form in which the positive electrode (10); the negative electrode (20); and the electrolyte layer (30) are included inside a case, and the lithium secondary battery unit module refers to a form in which a plurality of the lithium secondary battery unit cells are connected. For example, the metal-organic structure may be included as an independent configuration in an empty space inside the lithium secondary battery unit cell or an empty space outside the lithium secondary battery unit cell among the internal spaces of the lithium secondary battery module.

[0050] According to one embodiment, the size of the metal-organic framework may be 1 nm to 1 μm. In lithium secondary batteries employing sulfur (S), it is very difficult to suppress the generation of hydrogen sulfide itself, so it is required to release hydrogen sulfide to the outside. In addition, in lithium secondary batteries employing a general sulfide-based solid electrolyte and lithium sulfur, if lithium dendrites grow, the mechanical properties may deteriorate.

[0051] On the other hand, a lithium secondary battery according to an embodiment of the present invention includes a metal-organic framework, which adsorbs hydrogen sulfide (H2S) generated when sulfur (S) is exposed to moisture, thereby reducing the rate at which hydrogen sulfide (H2S) is generated externally, thereby providing an effect of reducing the decrease in ionic conductivity. Accordingly, hydrogen sulfide (H2S) generation can be reduced.

[0052] In a lithium secondary battery according to an embodiment, the hydrogen sulfide capture function may vary depending on the size, uniformity, pore size, etc. of the metal-organic framework. By controlling the size and uniformity of the metal-organic framework, the reduction in mechanical properties such as ionic conductivity and strength when sulfur (S) contained in the positive electrode active material layer is exposed to moisture can be minimized.

[0053] For example, the size of the metal-organic framework may be 1 nm to 1 μm, for example, 100 to 500 nm. In this specification, the size represents the major axis length. For example, if the metal-organic framework has another shape, the size represents the length of the longest side of the structure. If the metal-organic framework is spherical, the size may represent the average diameter.

[0054] For example, the specific surface area of ​​the metal-organic framework is 100 m 2 / g or wider, for example 500m 2 / g or more, specifically 100 to 4500 m 2 / g. The metal-organic framework has a wide specific surface area as in the above range, so that ionic conductivity can be improved at room temperature.

[0055] For example, the pore size of the metal-organic framework may be in a size range capable of capturing hydrogen sulfide. The pore size may refer to the average diameter of the pores when the pores are spherical, and may refer to the major axis length when the pores have other shapes. The pore size may be, for example, 1 nm to 10 nm, for example, 1 nm to 8 nm, for example, 1 nm to 5 nm. Specifically, the metal-organic framework may have a mesoporous structure with uniform pore sizes. The metal-organic framework may be dispersed as a plurality of primary particles within the matrix, and the size (diameter) of the plurality of primary particles may have a uniform size diameter distribution represented by the following Equation 1:

[0056] The metal-organic framework according to one embodiment has a uniform size represented by the following formula 1, and for example, the metal-organic framework may have a diameter distribution close to the average particle diameter.

[0057] [Formula 1]

[0058] 0.0 <σ2 / μ< 1.0

[0059] In the above equation 1, σ2 represents the variance of a plurality of primary particles measured using dynamic laser scattering, and specifically, σ2 represents the variance of the metal-organic framework primary particles, and the variance may correspond to a value equivalent to the square of the standard deviation of the average particle diameter of the metal-organic framework primary particles. μ represents the average particle diameter of the plurality of primary particles.

[0060] The average diameter of the plurality of primary particles described above may be 1 nm to 1 μm, for example, 10 nm to 900 nm, 100 nm to 800 nm, specifically, 300 nm to 500 nm. In addition, the shape of the primary particles may include various shapes such as sphere, oval, cylinder, triangle, square, or polyhedron, but the plurality of primary particles may be formed in one shape. For example, the plurality of primary particles may be spherical. In the above equation 1, σ2 / μ may be 0.01 to 0.5, for example, 0.1 to 0.3.

[0061] The metal-organic framework according to one embodiment may be a porous crystalline compound formed by chemical bonding of a metal ion of Group 2 to Group 15 or a metal ion cluster of Group 2 to Group 15 with an organic ligand. In this way, the metal-organic framework may have pores.

[0062] For example, the organic ligand may refer to an organic group capable of chemical bonding, such as a coordinate bond, an ionic bond, or a covalent bond. For example, the organic ligand may include two or more sites capable of binding to, for example, the metal ion described above. For example, the organic group may bind to the metal ion to form a stable structure.

[0063] The above group 2 to group 15 metal ions are cobalt (Co), nickel (Ni), molybdenum (Mo), tungsten (W), ruthenium (Ru), osdium (Os), cadmium (Cd), beryllium (Be), calcium (Ca), barium (Ba), strontium (Sr), iron (Fe), manganese (Mn), chromium (Cr), vanadium (V), aluminum (Al), titanium (Ti), zirconium (Zr), copper (Cu), zinc (Zn), magnesium (Mg), hafnium (Hf), niobium (Nb), tantalum (Ta), Re, rhodium (Rh), iridium (Ir), palladium (Pd), platinum (Pt), silver (Ag), scandium (Sc), yttrium (Y), indium (In), thallium (Tl), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), arsenic (As), At least one selected from antimony (Sb) and bismuth (Bi), and the organic ligand is an aromatic dicarboxylic acid, an aromatic tricarboxylic acid, an imidazole-based compound, a tetrazole-based compound, 1,2,3-triazole, 1,2,4-triazole, a pyrazole, an aromatic sulfonic acid, an aromatic phosphoric acid, an aromatic sulfinic acid, an aromatic phosphinic acid, bipyridine, an amino group, an imino group, an amide group, a methandithioic acid (-CS2H) group, a methandithioic acid anion (-CS 2- ) may be a group derived from at least one compound having at least one functional group selected from among a pyridine group, a pyrazine group, and a pyrazine group.

[0064] The above-mentioned aromatic dicarboxylic acids, aromatic tricarboxylic acids, etc. include benzenedicarboxylic acid, benzenetricarboxylic acid, biphenyldicarboxylic acid, triphenyldicarboxylic acid, etc.

[0065] The organic ligand described above may be a group derived from a compound represented by the following chemical formula.

[0066]

[0067] The metal-organic framework may include, for example, a compound represented by the following chemical formula 1.

[0068] [Chemical Formula 1]

[0069] M m O k X l L p

[0070] In the above chemical formula 1,

[0071] M is Ti 4+ , Zr 4+ , Mn 4+ , Si 4+ , Al 3+ , Cr 3+ , V 3+ , Ga 3+ , Mn 3+ , Zn 3+ , Mn 2+ , Mg 2+ , Fe 2+ , Fe 3+ and Cu 2+ At least one selected from the group consisting of, m is an integer from 1 to 10; k is 0 or an integer from 1 to 10; l is 0 or an integer from 1 to 10; p is an integer from 1 to 10, and X is OH - , Cl - , F - , I - , Br - , SO4 2-, NO3 - , ClO4 - , PF6 - , BF3 - , -(COO) n -, R1-(SO3) n -; or R1-(PO3) n- and R1 is at least one selected from hydrogen and C1-C30 alkyl groups, n is an integer from 1 to 4; L is a ligand containing q carboxylate groups (*COO-#) and radicals R, and q is an integer from 1 to 6, * represents a bonding position of the carboxylate group to R, # represents a bonding position of the carboxylate group to the metal ion M, and R is selected from substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C2-C30 alkenyl, substituted or unsubstituted C2-C30 alkynyl, substituted or unsubstituted mono- and polycyclic C1-C30 aryl, and substituted or unsubstituted mono- and polycyclic C1-C30 heteroaryl.

[0072] In the above chemical formula 1, m is 1, 2, 3, or 4, for example, 1 or 3. And k and l are 0, 1, 2, 3, or 4, for example, 0 or 1, respectively. p is 1, 2 3, or 4, for example, 1 or 3.

[0073] Among the definitions for the above R, substituted C1-C30 alkyl, substituted C2-C30 alkene, substituted C2-C30 alkynyl, substituted mono- and polycyclic C1-C30 aryl, mono- and polycyclic C1-C30 heteroaryl are C1-C10 alkyl, C2-C10 alkenyl, C2-C10 alkynyl, C3-C10 carbon ring, C1-C10 heteroalkyl, C1-C10 haloalkyl, C6-C10 aryl, C3-C10 heteroaryl, C5-C30 heterocycle, C1-C10 alkoxy, C6-C10 aryloxy, C3-C10 heteroaryloxy, C1-C10 alkylthio, C1-C10 heteroalkylthio, C6-C10 arylthio, C3-C10 Heteroarylthio, halogen atom, -CN, -CF3, -OH, -CHCl2, -CH2OH, -CH2CH2OH, -NH2, -CH2NH2, -COOH, -COONH2,-SO3H, -CH2SO2CH3, -PO3H2, halogen atom, C1-C30 alkyl group substituted with halogen atom (e.g., CCF3, CHCF2, CH2F, CCl3, etc.), C1-C30 alkoxy, C2-C30 alkoxyalkyl, hydroxy group, nitro group, cyano group, amino group, amidino group, hydrazine, hydrazone, carboxyl group or salt thereof, sulfonyl group, sulfamoyl group, sulfonic acid group or salt thereof, phosphoric acid or salt thereof, or C1-C30 alkyl group, C2-C30 alkenyl group, C2-C30 It may have one or more substituents selected from the group consisting of an alkynyl group, a C1-C30 heteroalkyl group, a C6-C30 aryl group, a C6-C30 arylalkyl group, a C6-C30 heteroaryl group, a C7-C30 heteroarylalkyl group, a C6-C30 heteroaryloxy group, a C6-C30 heteroaryloxyalkyl group, or a C6-C30 heteroarylalkyl group.

[0074] The above metal-organic framework may be a compound represented by the following chemical formula 2.

[0075] [Chemical Formula 2]

[0076] M' m O k X' lL' p

[0077] 상기 화학식 2 중 M'은 Ti 4+ , Zr 4+ , V 3+ , Zn +3 , Fe 2+ , Fe 3+ 및 Cu +2 중에서 선택된 하나 이상이며, L'은 C6H4(CO2 - )2(terephthalate), C2H2(CO2 - )2(fumarate), C4H4(CO2 - )2(muconate), C5H3S(CO2 - )2(2,5-thiophenedicarboxylate), C6H2N2(CO2)2(2,5-pyrazine dicarboxylate), C2H4(CO2 - )2(succinate), C3H6(CO2 - )2(glutarate), C4H8(CO2 - )2adipate, C 10 H6(CO2 - )2(naphtalene-2,6-dicarboxylate), C 12 H8(CO2 - )2(biphenyl-4,4’-dicarboxylate), C 12 H8N2(CO2 - )2(azobenzenedicarboxylate), C6H3(CO2 - )3(benzene-1,2,4-tricarboxylate), C6H3(CO2 - )3(benzene-1,3,5-tricarboxylate), C 24 H 15 (CO2 - )3(benzene-1,3,5-tribenzoate), C6H2(CO2 - )4(benzene-1,2,4,5-tetracarboxylate, C 10 H4(CO2 -)4(naphtalene-2,3,6,7-tetracarboxylate), C 10 H4(CO2 - )4(naphtalene-1,4,5,8-tetracarboxylate) and C 12 H6(CO2 - )4(biphenyl-3,5,3′,5′-tetracarboxylate), and X' is OH - , Cl - , F - , CH3COO - , PF6 - and ClO4 - One or more selected from among, m is an integer from 1 to 8; k is 0 or an integer from 1 to 8; l is 0 or an integer from 1 to 8; and p may be an integer from 1 to 8.

[0078] According to one embodiment, the metal-organic framework is, for example, Ti8O8(OH)4[O2C-C6H4-CO2] 6, Ti8O8(OH)4[O2C-C6H3(NH2)-CO2]6, VO[C6H4(CO2)2], Al(OH)[C6H4(CO2)2], Cr(OH)[C6H4(CO2)2], Al(OH)[C 10 H6(CO2)2], Al1O(OH) 18 (H2O)3[C6H3-(CO2)3]6.nH2O, Cr3OX l [C6H4(CO2)2]3(X=H, OH - , Cl - , F - , CH3COO - , PF6 - and ClO4 - One or more selected from, and l is 0 or an integer from 1 to 8), Cr3OX l [C 12 H8(CO2)2]3(X=H, OH - , Cl - , F - , CH3COO - , PF6- and ClO4 - One or more selected from, and l is 0 or an integer from 1 to 8), Cr3OX l [C6H3(CO2)3]3(X=H, OH - , Cl - , F - , CH3COO - , PF6 - and ClO4 - One or more selected from, and l is 0 or an integer from 1 to 8), Al8(OH) 15 (H2O)3[C6H3(CO2)3]3, V3OX l [C6H3(CO2)3]3(X=H, OH - , Cl - , F - , CH3COO - , PF6 - and ClO4 - wherein l is an integer from 0 to 8), ZrO[C6H4(CO2)2], and Ti8O8(OH)4[O2C-C6H3(NH2)-CO2]6.

[0079] The metal organic structure is specifically Ti8O8(OH)4[O2C-C6H4-CO2]6, Cu (bpy)(H2O)2(BF4)2(bpy){bpy= 4, 4'-bipyridine}, Zn4O(O2C-C6H4-CO2)3(Zn-terephthalic acid-MOF, Zn-MOF), Al(OH){O2C-C6H4-CO2}, Cu-BTC MOF (Copper benzene-l,3,5-tricarboxylate), ZIF 8 (2ㅡ Methyl imidazole zinc salt), MIL 53 (Aluminum terephthalate), Fe-BTC (Iron 1,3,5-benzenetricarboxylate), KRICT F100 (Iron trimesate), KRICT C100 (Chromium terephthalate), KRICT C200 (Copper trimesate), KRICT Z100 (Zirconium carboxylate) or a combination thereof, but is not necessarily limited thereto.

[0080] According to one embodiment, the pore size of the metal-organic framework may be 5 nm or less. For example, the pore size of the metal-organic framework may be 1 nm to 5 nm, 1 nm to 4 nm, or 1 nm to 3 nm.

[0081] [anode]

[0082] A positive electrode for a lithium secondary battery according to one embodiment includes a positive electrode current collector; and a positive electrode active material layer disposed on the positive electrode current collector, wherein the positive electrode active material layer may include lithium sulfur (Li2S).

[0083] [Anode: Anode active material layer]

[0084] According to one embodiment, a positive electrode includes a positive electrode current collector; and a positive electrode active material layer disposed on the positive electrode current collector. The positive electrode active material layer includes the composite positive electrode active material described above.

[0085] According to one embodiment, the positive electrode active material layer may further include a solid electrolyte. For example, the positive electrode may have a further reduced internal resistance by including a composite positive electrode active material and a solid electrolyte. Accordingly, the cycle characteristics of a secondary battery including the positive electrode may be further improved.

[0086] Referring to FIGS. 1 to 5, the positive electrode (10) includes a positive electrode current collector (11); and a positive electrode active material layer (12) disposed on the positive electrode current collector (11). The positive electrode active material layer (12) includes lithium sulfur (Li2S). For example, the positive electrode active material layer (12) may include the metal organic structure described above.

[0087] According to one embodiment, the positive electrode active material layer may include lithium sulfur (Li2S) and an ion-conducting lithium salt. According to one embodiment, the positive electrode active material layer may include a Li2S-containing composite, and the Li2S-containing composite may include a lithium salt (Li2S) and an ion-conducting lithium salt. For example, the Li2S-containing composite may include a composite of a lithium salt (Li2S) and an ion-conducting lithium salt.

[0088] For example, a composite of Li2S and a lithium salt is ductile, which distinguishes it from a brittle conventional oxide-based solid electrolyte, such as a garnet-structured oxide-based solid electrolyte. A composite of Li2S and a lithium salt is lithium-ion conductive, which distinguishes it from a conventional lithium-free metal oxide, such as alumina, which does not have lithium-ion conductivity. A composite of Li2S and a lithium salt is, for example, the result of mechanical milling of Li2S and a lithium salt. A composite of Li2S and a lithium salt is, for example, the result of a mechanochemical reaction of Li2S and a lithium salt, which distinguishes it from a simple mixture of Li2S and a lithium salt. A simple mixture of Li2S and a lithium salt can provide high interfacial resistance by failing to maintain a dense interface between Li2S and a lithium salt, which can result in an increase in the internal resistance of the solid electrolyte separator.

[0089] The complex of Li2S and lithium salt is Li2S-Li a X b (1≤a≤5, 1≤b≤5). Wherein X is I, Br, Cl, F, H, O, Se, Te, N, P, As, Sb, Al, B, OCl, PF6, BF4, SbF6, AsF6, ClO4, AlO2, AlCl4, NO3, CO3, BH4, SO4, BO3, PO4, NCl, NCl2, BN2 or a combination thereof. a is, for example, 1, 2, 3, 4 or 5. b is, for example, 1, 2, 3, 4 or 5. A lithium salt is, for example, a compound that does not contain sulfur (S).

[0090] According to one embodiment, the ion-conducting lithium salt may be a binary compound or a ternary compound. The ion-conducting lithium salt may be, for example, a binary compound composed of lithium and one element selected from Groups 13 to 17 of the periodic table of elements. The ion-conducting lithium salt may be, for example, a ternary compound composed of lithium and two elements selected from Groups 13 to 17 of the periodic table of elements. The binary compound may include, for example, LiI, LiBr, LiCl, LiF, LiH, Li2O, Li2Se, Li2Te, Li3N, Li3P, Li3As, Li3Sb, Li3Al2, LiB3, or a combination thereof. When the complex of Li2S and a lithium salt includes such a binary compound, the ion conductivity of the complex of Li2S and a lithium salt may be further improved. As a result, the cycle characteristics of a lithium secondary battery including such a positive electrode may be further improved.

[0091] The ternary compound may include, for example, Li3OCl, LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiAlO2, LiAlCl4, LiNO3, Li2CO3, LiBH4, Li2SO4, Li3BO3, Li3PO4, Li4NCl, Li5NCl2, Li3BN2, or a combination thereof. When the composite includes such a ternary compound, the ionic conductivity of the composite may be further improved. When the composite cathode active material includes such a composite, the internal resistance of the cathode may be further reduced. As a result, the cycle characteristics of a solid secondary battery including such a solid electrolyte separator may be further improved.

[0092] According to one embodiment, the molar ratio of Li2S to lithium salt in the complex of Li2S and lithium salt may be, for example, 50:50 to 95:5, 60:40 to 95:5, 60:40 to 90:10, 65:35 to 90:10, 65:35 to 85:15, or 70:30 to 85:15. The molar ratio of Li2S to lithium salt in the complex of Li2S and lithium salt may be, for example, 50:50 to 95:5, 50:50 to 90:10, 50:50 to 85:15, 50:50 to 80:20, 50:50 to 75:25, or 50:50 to 70:30. By maintaining the molar ratio of Li2S and lithium salt within this range, the cycle characteristics of lithium secondary batteries containing composite cathode active materials can be further improved. If the molar ratio of Li2S is excessively high, the ionic conductivity enhancement effect of the lithium salt may be minimal. If the molar ratio of Li2S is excessively high, the energy density of lithium secondary batteries containing composite cathode active materials may be reduced.

[0093] According to one embodiment, the positive electrode active material layer may further include a carbon-based material. For example, the Li2S-containing composite may further include a carbon-based material. For example, the Li2S-containing composite may be a composite of Li2S, an ion-conducting lithium salt, and a carbon-based material.

[0094] For example, the carbon-based material may be any material that contains carbon atoms and is used as a conductive material in the relevant technical field. The carbon-based material may be, for example, crystalline carbon, amorphous carbon, or a combination thereof. The carbon-based material may be, for example, a sintered product of a carbon precursor. The carbon-based material may be, for example, a carbon nanostructure. The carbon nanostructure may be, for example, a one-dimensional carbon nanostructure, a two-dimensional carbon nanostructure, a three-dimensional carbon nanostructure, or a combination thereof. The carbon nanostructure may be, for example, a carbon nanotube, a carbon nanofiber, a carbon nanobelt, a carbon nanorod, a graphene, or a combination thereof.

[0095] The carbon-based material may be, for example, a porous carbon-based material or a non-porous carbon-based material. The porous carbon-based material may include, for example, periodic and regular two-dimensional or three-dimensional pores. The porous carbon-based material may be, for example, carbon black such as Ketjen black, acetylene black, Denka black, thermal black, channel black, etc.; graphite, activated carbon, or a combination thereof. The form of the carbon-based material may be, for example, a particle form, a sheet form, a flake form, etc., but is not limited thereto, and any form that is used as a carbon-based material in the art may be used.

[0096] The carbon-based material may include, for example, a fibrous carbon-based material. Since the composite of Li2S, a lithium salt, and a carbon-based material includes the fibrous carbon-based material, the electronic conductivity of the composite of Li2S, a lithium salt, and a carbon-based material can be further improved. Since the composite of Li2S, a lithium salt, and a carbon-based material includes the fibrous carbon-based material, electronic conduction can be more easily performed from the surface to the inside of the composite of Li2S, a lithium salt, and a carbon-based material. The internal resistance of a dry positive electrode film including a composite of Li2S, a lithium salt, and a carbon-based material can be reduced, and the cycle characteristics of a lithium secondary battery including the dry positive electrode film can be further improved.

[0097] The aspect ratio of the fibrous carbon-based material may be, for example, 2 or more, 3 or more, 4 or more, 5 or more, 10 or more, or 20 or more. The aspect ratio of the fibrous carbon-based material may be, for example, 2 to 30, 3 to 30, 4 to 30, 5 to 30, 10 to 30, or 20 to 30. The aspect ratio of the fibrous carbon-based material may be, for example, 2 to 30, 2 to 20, 2 to 10, 2 to 8, 2 to 5, or 2 to 4. When the fibrous carbon-based material has an aspect ratio in this range, the overall electronic conductivity of the composite of Li2S, a lithium salt, and a carbon-based material is improved, and the imbalance of local electronic conductivity within the composite of Li2S, a lithium salt, and a carbon-based material can be further alleviated.

[0098] The above fibrous carbon-based material may include, for example, a carbon nanostructure. The carbon nanostructure may include, for example, carbon nanofibers (CNF), carbon nanotubes (CNT), carbon nanobelts, carbon nanorods, or a combination thereof.

[0099] The above carbon nanostructure can form a primary carbon nanostructure composed of a single carbon nanostructure and a secondary carbon nanostructure composed of a plurality of carbon nanostructures aggregated together.

[0100] The diameter of the primary carbon nanostructure may be, for example, 1 nm to 200 nm, 1 nm to 150 nm, 1 nm to 100 nm, 1 nm to 50 nm, 1 nm to 30 nm, or 1 nm to 20 nm. The length of the primary carbon nanostructure may be, for example, 10 nm to 2 ㎛, 10 nm to 1.5 ㎛, 10 nm to 1 ㎛, 10 nm to 500 nm, 10 nm to 400 nm, 10 nm to 300 nm, 10 nm to 200 nm, or 10 nm to 100 nm. The diameter and length of the primary carbon nanostructure may be measured from a scanning electron microscope (SEM) or transmission electron microscope (TEM) image. Alternatively, the diameter and / or length of the primary carbon nanostructure may be measured by laser diffraction.

[0101] The secondary carbon nanostructure is, for example, a structure formed by assembling primary carbon nanostructures to form a bundle or bunch shape, in whole or in part. The secondary carbon nanostructure may include, for example, a bundle-type carbon nanostructure, a rope-type carbon nanostructure, or a combination thereof. The diameter of the secondary carbon nanostructure may be, for example, 2 nm to 200 nm, 3 nm to 150 nm, 5 nm to 100 nm, 5 nm to 50 nm, 5 nm to 30 nm, or 5 nm to 20 nm. The length of the secondary carbon nanotube structure can be, for example, 20 nm to 2 ㎛, 30 nm to 1.5 ㎛, 50 nm to 1 ㎛, 50 nm to 500 nm, 50 nm to 400 nm, 50 nm to 300 nm, 50 nm to 200 nm, or 50 nm to 100 nm or more. The diameter and length of the secondary carbon nanostructure can be measured from a scanning electron microscope (SEM) image or an optical microscope. Alternatively, the diameter and / or length of the secondary carbon nanostructure can be measured by laser diffraction. The secondary carbon nanostructure can be converted into a primary carbon nanostructure, for example, by dispersing it in a solvent or the like, and then used to prepare a composite of Li2S, a lithium salt, and a carbon-based material.

[0102] In the composite of the above Li2S, lithium salt, and carbon-based material, the content of the lithium salt may be, for example, 1 to 40 wt%, 5 to 35 wt%, 10 to 35 wt%, 15 to 35 wt%, 20 to 35 wt%, or 25 to 35 wt% of the total weight of the composite of the Li2S, lithium salt, and carbon-based material. If the content of the lithium salt increases excessively, the energy density of the lithium secondary battery may decrease. If the content of the lithium salt is excessively low, the ionic conductivity of the composite of the Li2S, lithium salt, and carbon-based material may decrease, which may increase the internal resistance of the dry positive electrode film. As a result, the cycle characteristics of the lithium secondary battery including the dry positive electrode film may deteriorate.

[0103] In the composite of Li2S, lithium salt, and carbon-based material, the molar ratio of Li2S and lithium salt may be, for example, 50:50 to 95:5, 60:40 to 95:5, 60:40 to 90:10, 65:35 to 90:10, 65:35 to 85:15, or 70:30 to 85:15. In the composite of Li2S, lithium salt, and carbon-based material, the molar ratio of Li2S and lithium salt may be, for example, 50:50 to 95:5, 50:50 to 90:10, 50:50 to 85:15, 50:50 to 80:20, 50:50 to 75:25, or 50:50 to 70:30. By maintaining the molar ratio of Li2S and lithium salt within this range, the cycle characteristics of lithium secondary batteries containing dry cathode films can be further improved. If the molar ratio of Li2S is excessively high, the effect of lithium salt on improving ionic conductivity may be minimal. If the molar ratio of Li2S is excessively high, the energy density of lithium secondary batteries containing composite cathode active materials may be reduced.

[0104] According to one embodiment, the content of the carbon-based material included in the composite of Li2S, lithium salt, and carbon-based material may be, for example, 1 to 20 wt%, 5 to 20 wt%, or 10 to 20 wt% of the total weight of the composite. If the content of the carbon-based material increases excessively, the energy density of the positive electrode film and the lithium secondary battery may decrease. If the content of the carbon-based material decreases excessively, the electronic conductivity of the composite of Li2S, lithium salt, and carbon-based material may decrease, thereby increasing the internal resistance of the positive electrode film. As a result, the cycle characteristics of the secondary battery may deteriorate.

[0105] According to one embodiment, the composite of Li2S and a lithium salt or the composite of Li2S, a lithium salt, and a carbon-based material may include, for example, a solid solution of Li2S and a lithium salt. The ionic conductivity of the composite may increase by including the solid solution of Li2S and a lithium salt. For example, since the solid solution of Li2S and a lithium salt includes lithium ions arranged within Li2S crystallites, the ionic conductivity of the solid solution of Li2S and a lithium salt may be improved compared to the ionic conductivity of Li2S. Consequently, the ionic conductivity of the composite may be improved and the internal resistance of the composite may be reduced. By including such a composite in the positive electrode, the internal resistance of the positive electrode may be further reduced. Consequently, the cycle characteristics of a lithium secondary battery including such a positive electrode may be further improved.

[0106] According to one embodiment, the size of Li2S crystallites obtained from the XRD spectrum of the composite of Li2S and a lithium salt or the composite of Li2S, a lithium salt and a carbon-based material may be, for example, 30 nm or less, 25 nm or less, or 20 nm or less. The size of Li2S crystallites obtained from the XRD spectrum of the composite may be, for example, 1 to 20 nm, 1 to 15 nm, or 3 to 10 nm. As the size of Li2S crystallites decreases, the contact area between Li2S and a lithium salt may further increase. As the contact area between Li2S and a lithium salt further increases, the ionic conductivity of the composite of Li2S and a lithium salt may further increase. The internal resistance of the positive electrode may further decrease when the positive electrode includes such a composite. As a result, the cycle characteristics of a solid secondary battery including such a positive electrode may further improve.

[0107] For example, since Li2S has low ionic conductivity, a complex with a lithium salt is formed to overcome this drawback. A complex of Li2S and a lithium salt or a composite of Li2S and a lithium salt and a carbon-based material can provide improved ionic conductivity compared to Li2S alone. The content of Li2S in the Li2S-containing composite may be 50 to 95 wt%, 50 to 90 wt%, 50 to 80 wt%, or 50 to 70 wt% of the total weight of the Li2S-containing composite. By having the composite having a Li2S content in this range, a cathode with improved ionic conductivity and durability can be manufactured. The content of the lithium salt in the composite of Li2S and a lithium salt may be 5 to 50 wt%, 10 to 50 wt%, 20 to 50 wt%, or 30 to 50 wt% of the total weight of the Li2S-containing composite.

[0108] The Mohs hardness of the lithium salt and the carbon-based material may be greater than that of Li2S. The Mohs hardness of Li2S is, for example, 0.6 or less. The Mohs hardness of the lithium salt may be 0.7 or more, 0.8 or more, 0.9 or more, 1.0 or more, 1.5 or more, or 2.0 or more. Since the lithium salt has a Mohs hardness in this range, the pulverization of Li2S can be performed more easily during the milling process, and a solid solution of Li2S and the lithium salt can be formed more easily. The Mohs hardness of LiI is, for example, 2.0. The Mohs hardness of the carbon-based material may be 0.7 or more, 0.8 or more, 0.9 or more, 1.0 or more, 1.2 or more, or 1.5 or more, respectively. Since the carbon-based material has a Mohs hardness in this range, the grinding of Li2S can be performed more easily during the milling process, and a composite of Li2S, a lithium salt, and a carbon-based material can be formed more easily. The modal hardness of carbon nanofibers (CNF) is, for example, 1.5.

[0109] The ionic conductivity of a complex of Li2S and a lithium salt or a complex of Li2S, a lithium salt and a carbon-based material is, for example, 1×10 at 25°C. -5 S / cm or more, 2×10 -5 S / cm or more, 4×10 -5 S / cm or more, 6×10 -5 S / cm or more, 8×10 -5 S / cm or more or 1×10 -4It can be S / cm or more. The ionic conductivity can be measured using, for example, electrochemical impedance spectroscopy, direct current polarization method, etc. Since the complex of Li2S and lithium salt has an ionic conductivity in this range, the internal resistance of the positive electrode including the complex of Li2S and lithium salt can be further reduced. The cycle characteristics of a solid secondary battery including the positive electrode can be improved.

[0110] According to one embodiment, the content of the Li2S-containing complex may include 40 to 90 wt%, 40 to 80 wt%, 50 to 80 wt%, or 50 to 70 wt% based on the total weight of the positive electrode active material layer (12). If the content of the Li2S-containing complex is excessively reduced, the energy density of the secondary battery is reduced. If the content of the Li2S-containing complex is excessively increased, deterioration of the positive electrode may be accelerated due to volume change of the positive electrode during charge and discharge. As a result, the cycle characteristics of the lithium secondary battery (1) may be deteriorated.

[0111] The cathode active material layer (12) may additionally include a composite cathode active material in addition to the Li2S-containing complex described above.

[0112] The composite cathode active material may include, for example, a Li2S-containing composite. The Li2S composite may include, for example, a composite of Li2S and a carbon-based material, a composite of Li2S and a carbon-based material and a solid electrolyte, a composite of Li2S and a solid electrolyte, a composite of Li2S and a lithium salt, a composite of Li2S and a metal carbide, a composite of Li2S and a carbon-based material and a metal carbide, a composite of Li2S and a metal nitride, a composite of Li2S and a carbon-based material and a metal nitride, or a combination thereof.

[0113] The above composite of Li2S and a carbon-based material includes a carbon-based material. The carbon-based material refers to the carbon-based material of the Li2S-containing composite described above. The method for producing the composite of Li2S and a carbon-based material may be a dry method, a wet method, or a combination thereof, but is not limited thereto, and any method used in the relevant technical field may be used. The method for producing the composite of Li2S and a carbon-based material includes, but is not limited to, milling, heat treatment, deposition, etc., and any method used in the relevant technical field may be used.

[0114] A composite of Li2S, a carbon-based material, and a solid electrolyte includes a carbon-based material and a solid electrolyte. The carbon-based material refers to the Li2S-containing composite described above. The solid electrolyte can be, for example, any material used as an ion-conducting material in the relevant technical field. The solid electrolyte is, for example, an inorganic solid electrolyte. The solid electrolyte is, for example, a crystalline solid electrolyte, an amorphous solid electrolyte, or a combination thereof. The solid electrolyte is, for example, a sulfide-based solid electrolyte, an oxide-based solid electrolyte, or a combination thereof. The sulfide-based solid electrolyte includes, for example, Li, S, and P, and may optionally further include a halogen element. The sulfide-based solid electrolyte can be selected from among the sulfide-based solid electrolytes used in the electrolyte layer. The sulfide-based solid electrolyte has, for example, a molecular weight of 1×10 at room temperature. -5 It can have an ionic conductivity of S / cm or more. The oxide-based solid electrolyte contains, for example, Li, O, and transition metal elements, and may optionally contain other elements. The oxide-based solid electrolyte has, for example, an ionic conductivity of 1×10 at room temperature. -5 It may be a solid electrolyte having an ionic conductivity of S / cm or more. The oxide-based solid electrolyte may be selected from among oxide-based solid electrolytes used in the electrolyte layer.

[0115] The composite of Li2S and a solid electrolyte includes a solid electrolyte. The solid electrolyte refers to the composite of Li2S, a carbon-based material, and a solid electrolyte described above.

[0116] The composite of Li2S and a lithium salt comprises Li2S and a lithium salt. The lithium salt refers to the lithium salt of the composite cathode active material described above. The lithium salt is particularly one or more lithium halide compounds selected from LiF, LiCl, LiBr, and LiI. The composite of Li2S and a lithium salt may be, for example, a composite of Li2S and a lithium halide. The composite of Li2S and a lithium salt may provide improved ionic conductivity by including a lithium halide compound. The composite of Li2S and a lithium salt is distinguished from a simple mixture of Li2S, a carbon-based material, and a lithium salt. A simple mixture of Li2S and a lithium salt may provide high interfacial resistance by failing to maintain a dense interface between Li2S and a lithium salt, which may result in reduced cycle life characteristics of an all-solid-state secondary battery.

[0117] The composite of Li2S and metal carbide includes metal carbide. The metal carbide is, for example, a two-dimensional metal carbide. The two-dimensional metal carbide is, for example, M n+1 C n T x (M is a transition metal, T is a terminal group, T is O, OH and / or F, n=1, 2, or 3, and x is the number of terminal groups) is expressed as 2D metal carbides, for example, Ti2CT x , (Ti 0.5 , Nb 0.5 )2CT x , Nb2CT x , V2CT x , Ti3C2T x , (V 0.5 , Cr 0.5 )3C2T x , Ti3CNT x , Ta4C3T x , Nb4C3T xor a combination thereof. The surface of the two-dimensional metal carbide is terminated with O, OH and / or F.

[0118] A composite of Li2S, a carbon-based material, and a metal carbide includes a carbon-based material and a metal carbide. The carbon-based material refers to the composite of Li2S and a carbon-based material described above. The metal carbide refers to the composite of Li2S and a metal carbide described above.

[0119] The complex of Li2S and metal nitride includes a metal nitride. The metal nitride is, for example, a two-dimensional metal nitride. The two-dimensional metal nitride is, for example, M n+1 N n T x (M is a transition metal, T is a terminal group, T is O, OH and / or F, n=1, 2, or 3, and x is the number of terminal groups) is expressed as The surface of the two-dimensional metal nitride is terminated with O, OH and / or F.

[0120] A composite of Li2S, a carbon-based material, and a metal nitride includes a carbon-based material and a metal nitride. The carbon-based material refers to the composite of Li2S and a carbon-based material described above. The metal carbide refers to the composite of Li2S and a metal nitride described above.

[0121] The cathode active material layer (12) may additionally include, for example, a sulfide-based compound that is distinct from the Li2S-containing complex described above. The sulfide-based compound may be, for example, a compound containing a metal element other than Li and the element sulfur. The sulfide-based compound may be, for example, a compound containing a metal element belonging to Groups 1 to 14 of the Periodic Table of Elements having an atomic weight of 10 or more and the element sulfur. The sulfide-based compound may be, for example, FeS2, VS2, NaS, MnS, FeS, NiS, CuS, or a combination thereof. By the cathode active material layer additionally including a sulfide-based compound, the cycle characteristics of the lithium secondary battery may be further improved. The content of the sulfide-based compound included in the cathode active material layer (12) may be 10 wt% or less, 5 wt% or less, 3 wt% or less, or 1 wt% or less of the total weight of the cathode active material layer (12).

[0122] [Anode: Solid electrolyte]

[0123] The positive electrode active material layer (12) may further include, for example, a solid electrolyte. The solid electrolyte may be, for example, a sulfide-based solid electrolyte. The solid electrolyte included in the positive electrode (10) may be the same as or different from the solid electrolyte included in the electrolyte layer (30). For more details on the solid electrolyte, refer to the electrolyte layer (30) section.

[0124] The solid electrolyte included in the positive electrode active material layer (12) may have a smaller average D50 particle diameter than the solid electrolyte included in the electrolyte layer (30). For example, the average D50 particle diameter of the solid electrolyte included in the positive electrode active material layer (12) may be 90% or less, 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, or 20% or less of the average D50 particle diameter of the solid electrolyte included in the electrolyte layer (30). The average D50 particle diameter is, for example, a median particle diameter (D50). The median particle diameter (D50) is the size of particles corresponding to 50% of the cumulative volume, calculated from the side of particles having a small particle size in a size distribution of particles measured by, for example, a laser diffraction method.

[0125] The solid electrolyte may be included in an amount of 10 to 60 parts by weight, 10 to 50 parts by weight, 20 to 50 parts by weight, or 30 to 50 parts by weight, based on 100 parts by weight of the positive electrode active material layer (12). If the content of the solid electrolyte is excessively reduced, the internal resistance of the positive electrode may increase, thereby deteriorating the cycle characteristics of the secondary battery. If the content of the sulfide-based solid electrolyte is excessively increased, the energy density of the secondary battery (1) may be reduced.

[0126] [Polar: Challenger]

[0127] The cathode active material layer (12) may further include a conductive material. The conductive material may be, for example, a carbon-based conductive material, a metal-based conductive material, or a combination thereof. The carbon-based conductive material may be, for example, graphite, carbon black, acetylene black, Ketjen black, carbon fiber, or a combination thereof, but is not limited thereto, and any material used as a carbon-based conductive material in the art may be used. The metal-based conductive material may be, for example, metal powder, metal fiber, or a combination thereof, but is not limited thereto, and any material used as a metal-based conductive material in the art may be used. The content of the conductive material included in the cathode active material layer (12) may be, for example, 1 wt% to 30 wt%, 1 wt% to 20 wt%, or 1 wt% to 10 wt% of the total weight of the cathode active material layer (12).

[0128] The cathode active material layer (12) includes a carbon-based material, and the carbon-based material may be disposed only in the composite cathode active material. The cathode active material layer (12) may not additionally include a separate carbon-based material other than the composite cathode active material including the carbon-based material. Since the cathode active material layer does not include a separate carbon-based material, the energy density of the cathode and the secondary battery (1) can be improved and the manufacturing process can be simplified.

[0129] [Positive: Binder]

[0130] The positive electrode active material layer (12) may further include a binder. The binder may be, for example, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, etc., but is not limited thereto, and any binder used in the relevant technical field may be used. The binder content included in the positive electrode active material layer (12) may be, for example, 1 wt% to 10 wt% of the total weight of the positive electrode active material layer (12). The binder may be omitted.

[0131] [Positive: Other additives]

[0132] The cathode active material layer (12) may further include additives such as fillers, coating agents, dispersants, and ion conductive aids in addition to the composite cathode active material, solid electrolyte, binder, and conductive agent described above.

[0133] As fillers, coating agents, dispersants, ion conductivity aids, etc. that the positive electrode active material layer (12) may include, known materials generally used in electrodes of lithium secondary batteries may be used.

[0134] [Anode: Anode current collector]

[0135] The positive electrode collector (11) uses a plate or foil made of, 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. The positive electrode collector (11) may be omitted. The thickness of the positive electrode collector (11) is, for example, 1 µm to 100 µm, 1 µm to 50 µm, 5 µm to 25 µm, or 10 µm to 20 µm.

[0136] The cathode current collector (11) may include, for example, a base film and a metal layer disposed on one or both sides of the base film. The base film may include, for example, a polymer. The polymer may be, for example, a thermoplastic polymer. The polymer may include, for example, polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polybutylene terephthalate (PBT), polyimide (PI), or a combination thereof. The base film may be, for example, an insulator. Since the base film includes an insulating thermoplastic polymer, when a short circuit occurs, the base film softens or liquefies, thereby blocking battery operation and suppressing a rapid increase in current. The metal layer 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), or an alloy thereof. The metal layer can act as an electrochemical fuse and perform a short-circuit prevention function by being cut in case of overcurrent. The limit current and maximum current can be controlled by adjusting the thickness of the metal layer. The metal layer can be plated or deposited on the base film. When the thickness of the metal layer is reduced, the limit current and / or maximum current of the positive electrode current collector (11) decreases, thereby improving the stability of the lithium secondary battery in case of a short circuit. A lead tab can be added on the metal layer for connection to the outside. The lead tab can be welded to the metal layer or the metal layer / base film laminate by ultrasonic welding, laser welding, spot welding, etc. During welding, the base film and / or the metal layer melt, so that the metal layer can be electrically connected to the lead tab. In order to make the welding of the metal layer and the lead tab more solid, a metal chip can be added between the metal layer and the lead tab.The metal piece may be a thin piece of the same material as the metal of the metal layer. The metal piece may be, for example, a metal foil, a metal mesh, etc. The metal piece may be, for example, aluminum foil, copper foil, SUS foil, etc. After the metal piece is placed on the metal layer, the lead tab may be welded to the metal piece / metal layer laminate or the metal piece / metal layer / base film laminate. During welding, the base film, the metal layer, and / or the metal piece may melt, so that the metal layer or the metal layer / metal piece laminate may be electrically connected to the lead tab. A metal chip and / or a lead tab may be added to a portion of the metal layer. The base film may have a thickness of, for example, 1 to 50 μm, 1.5 to 50 μm, 1.5 to 40 μm, or 1 to 30 μm. When the base film has a thickness in this range, the weight of the electrode assembly can be more effectively reduced. The melting point of the base film may be, for example, 100 to 300°C, 100 to 250°C or less, or 100 to 200°C. Since the base film has a melting point within this range, the base film can be melted and easily bonded to the lead tab during the welding process of the lead tab. To improve the adhesion between the base film and the metal layer, a surface treatment such as corona treatment may be performed on the base film. The thickness of the metal layer may be, for example, 0.01 to 3 μm, 0.1 to 3 μm, 0.1 to 2 μm, or 0.1 to μm. Since the metal layer has a thickness within this range, conductivity can be maintained while ensuring the stability of the electrode assembly. The thickness of the metal piece may be, for example, 2 to 10 μm, 2 to 7 μm, or 4 to 6 μm. Since the metal piece has a thickness within this range, the connection between the metal layer and the lead tab can be performed more easily. By having this structure, the positive electrode collector (11) can reduce the weight of the positive electrode and consequently improve the energy density of the positive electrode and lithium secondary battery.

[0137] According to one embodiment, the positive electrode current collector (11) may include the metal organic structure described above.

[0138] [Anode: Inert member]

[0139] Referring to FIGS. 4 and 5, the positive electrode (10) includes a positive electrode current collector (11) and a positive electrode active material layer (12) disposed on one side of the positive electrode current collector. An inactive member (40) is disposed on one side of the positive electrode (10). Referring to FIG. 4, the inactive member (40) is disposed on one side of the positive electrode active material layer (12) and the positive electrode current collector (11). Referring to FIG. 5, the inactive member (40) is disposed on one side of the positive electrode active material layer (12) and between the electrolyte layer (30) and the positive electrode current collector (11) facing the electrolyte layer (30). The inactive member (40) is not disposed on one side of the positive electrode current collector (11). The electrolyte layer (30) may be, for example, a solid electrolyte layer.

[0140] According to one embodiment, the inert member (40) may include the metal organic structure described above.

[0141] By including the inert member (40), cracking of the electrolyte layer (30) is prevented during manufacture and / or charging and discharging of the lithium secondary battery (1), thereby improving the cycle characteristics of the lithium secondary battery (2). In a lithium secondary battery (1) that does not include the inert member (40), cracking occurs in the electrolyte layer (30) in contact with the positive electrode (10) when uneven pressure is applied to the electrolyte layer (30) during manufacture and / or charging and discharging of the lithium secondary battery (1), and the possibility of a short circuit occurring due to growth of lithium metal through the crack increases.

[0142] In the lithium secondary battery (1), the thickness of the inert member (40) is greater than or equal to the thickness of the positive electrode active material layer (12). Alternatively, in the lithium secondary battery (1), the thickness of the inert member (40) is substantially equal to the thickness of the positive electrode (10). Since the thickness of the inert member (40) is equal to the thickness of the positive electrode (10), a uniform pressure is applied between the positive electrode (10) and the electrolyte layer (30), and the positive electrode (10) and the electrolyte layer (30) are sufficiently adhered to each other, so that the interfacial resistance between the positive electrode (10) and the electrolyte layer (30) can be reduced. In addition, since the electrolyte layer (30) is sufficiently sintered during the pressurized manufacturing process of the lithium secondary battery (1), the internal resistance of the electrolyte layer (30) and the lithium secondary battery (1) including the same is reduced.

[0143] The inert member (40) surrounds the side surface of the positive electrode (10) and is in contact with the electrolyte layer (30). By the inert member (40) surrounding the side surface of the positive electrode (10) and being in contact with the electrolyte layer (30), cracks in the electrolyte layer (30) that occur due to a pressure difference during the pressing process in the electrolyte layer (30) that does not come into contact with the positive electrode (20) can be effectively suppressed. The inert member (40) surrounds the side surface of the positive electrode (10) and is separated from the negative electrode (20), more specifically, the first negative electrode active material layer (22). The inert member (40) surrounds the side surface of the positive electrode (10), is in contact with the electrolyte layer (30), and is separated from the negative electrode (20). Therefore, the possibility of a short circuit occurring due to physical contact between the positive electrode (10) and the first negative electrode active material layer (22) or a short circuit occurring due to overcharging of lithium, etc., is suppressed. For example, by placing an inert member (40) on one side of the positive electrode active material layer (12) and simultaneously on one side of the positive electrode current collector (11), the possibility of a short circuit occurring due to contact between the positive electrode current collector (11) and the negative electrode (20) is more effectively suppressed.

[0144] Referring to FIGS. 4 and 5, the inert member (40) extends from one side of the anode (30) to the end of the electrolyte layer (30). By extending the inert member (40) to the end of the electrolyte layer (30), cracks occurring at the end of the electrolyte layer (30) can be suppressed. The end of the electrolyte layer (30) is the outermost part that comes into contact with the side of the electrolyte layer (30) to be described later. The inert member (40) extends to the outermost part that comes into contact with the side of the electrolyte layer (30) to be described later. The inert member (40) is separated from the cathode (20) to be described later. The inert member (40) extends to the end of the electrolyte layer (30), but does not contact the cathode (20). The inert member (40) fills, for example, a space extending from one side of the anode (30) to the end of the electrolyte layer (30).

[0145] Referring to FIGS. 4 and 5, the width of the inert member (40) extending from one side of the positive electrode (10) to the end of the electrolyte layer (30) is, for example, 1 to 30%, 1 to 25%, 1 to 20%, 1 to 15%, 1 to 10%, or 1 to 5% of the width between one side of the positive electrode (10) and the other side opposite to the one side. If the width of the inert member (40) is excessively large, the energy density of the lithium secondary battery (1) is reduced. If the width of the inert member (40) is excessively small, the effect of arranging the inert member (40) is minimal.

[0146] The area of ​​the anode (10) is smaller than the area of ​​the electrolyte layer (30) in contact with the anode (10). An inert member (40) is arranged to surround the side of the anode (10) to compensate for the area difference between the anode (10) and the electrolyte layer (30). By compensating for the difference between the area of ​​the anode (10) and the area of ​​the electrolyte layer (30), cracks in the electrolyte layer (30) caused by the pressure difference during the pressing process are effectively suppressed. For example, the sum of the area of ​​the anode (10) and the area of ​​the inert member (40) is equal to the area of ​​the electrolyte layer (30). The electrolyte layer (30) may be, for example, a solid electrolyte layer.

[0147] The area of ​​the anode (10) is, for example, less than 100%, 99% or less, 98% or less, 97% or less, 96% or less, or 95% or less of the area of ​​the electrolyte layer (30). The area of ​​the anode (10) is, for example, 50% to less than 100%, 50% to 99%, 55% to 98%, 60% to 97%, 70% to 96%, 80% to 95%, or 85% to 95% of the area of ​​the electrolyte layer (30).

[0148] If the area of ​​the positive electrode (10) is equal to or larger than the area of ​​the electrolyte layer (30), the possibility of a short circuit occurring due to physical contact between the positive electrode (10) and the first negative electrode active material layer (22) or overcharging of lithium increases. The area of ​​the positive electrode (10) is, for example, equal to the area of ​​the positive electrode active material layer (12). The area of ​​the positive electrode (10) is, for example, equal to the area (11) of the positive electrode current collector.

[0149] The area of ​​the inert member (40) is, for example, 50% or less, 40% or less, 30% or less, 20% or less, or 10% or less of the area of ​​the anode (10). The area of ​​the inert member (40) is, for example, 1% to 50%, 5% to 40%, 5% to 30%, 5% to 20%, or 5% to 15% of the area of ​​the anode (10).

[0150] The area (S1) of the positive electrode (10) is smaller than the area (S4) of the negative electrode current collector (21). The area (S1) of the positive electrode (10) is, for example, less than 100%, 99% or less, 98% or less, 97% or less, 96% or less, or 95% or less of the area (S4) of the negative electrode current collector (21). The area (S1) of the positive electrode (10) is, for example, 50% to less than 100%, 50% to 99%, 55% to 98%, 60% to 97%, 70% to 96%, 80% to 95%, or 85% to 95% of the area (S4) of the negative electrode current collector (21). The area (S4) of the negative electrode current collector (21) is, for example, the same as the area of ​​the negative electrode (20). The area (S4) of the negative electrode current collector (21) is, for example, the same as the area of ​​the first negative electrode active material layer (22).

[0151] As used herein, “same” area, length, width, thickness, and / or shape includes all instances of having “substantially the same” area, length, width, thickness, and / or shape, except where the area, length, width, thickness, and / or shape are intentionally different from each other. “Same” area, length, width, and / or thickness includes a range where the unintentional difference in the area, length, width, and / or thickness of the compared objects is, for example, less than 3%, less than 2%, less than 1%, less than 0.5%, or less than 0.1%.

[0152] The thickness of the inert member (40) is, for example, greater than the thickness of the first negative electrode active material layer (22) described later. The thickness of the first negative electrode active material layer (22) is, for example, 50% or less, 40% or less, 30% or less, 20% or less, or 10% or less of the thickness of the inert member (40). The thickness of the first negative electrode active material layer (22) is, for example, 1% to 50%, 1% to 40%, 1% to 30%, 1% to 20%, or 1% to 10% of the thickness of the inert member (40).

[0153] The inert member (40) may be a gasket. By using a gasket as the inert member (40), cracks in the electrolyte layer (30) caused by a pressure difference during the pressing process can be effectively suppressed. For example, the gasket may include a metal-organic framework.

[0154] The inert member (40) has, for example, a single-layer structure. Alternatively, although not shown in the drawing, the inert member (40) may have a multi-layer structure. In the inert member (40) having a multi-layer structure, each layer may have a different composition. The inert member having a multi-layer structure may have, for example, a two-layer structure, a three-layer structure, a four-layer structure, or a five-layer structure. The inert member (40) having a multi-layer structure may include, for example, one or more adhesive layers and one or more support layers. The adhesive layer effectively prevents, for example, a separation between the positive electrode (10) and the electrolyte layer (30) due to a change in the volume of the positive electrode (10) that occurs during the charge / discharge process of the lithium secondary battery (10), and improves the film strength of the inert member (40) by providing a bonding force between the support layer and other layers. The support layer provides support to the inert member (40), prevents unevenness of pressure applied to the electrolyte layer (30) during the pressurization process or the charge / discharge process, and prevents deformation of the lithium secondary battery (1) being manufactured.

[0155] The inert member (40) is, for example, a flame-retardant inert member. The flame-retardant inert member can prevent thermal runaway and ignition of the lithium secondary battery (1) by providing flame retardancy. Consequently, the safety of the lithium secondary battery (1) is further improved. The flame-retardant inert member prevents deterioration of the lithium secondary battery (1) by absorbing residual moisture within the lithium secondary battery (1), thereby improving the lifespan characteristics of the lithium secondary battery (1). For example, the flame-retardant inert member may include the above-described metal-organic framework.

[0156] The flame-retardant inert member includes, for example, a matrix and a filler. The matrix includes, for example, a substrate and a reinforcing material. The matrix includes, for example, a fibrous substrate and a fibrous reinforcing material. Since the matrix includes the substrate, the matrix can have elasticity. Therefore, the matrix can effectively accommodate volume changes during charging and discharging of the lithium secondary battery (1) and can be arranged at various positions. The substrate included in the matrix includes, for example, a first fibrous material. Since the substrate includes the first fibrous material, the volume changes of the positive electrode (30) occurring during the charging and discharging process of the lithium secondary battery (1) can be effectively accommodated and deformation of the inert member (40) due to the volume changes of the positive electrode (30) can be effectively suppressed. The first fibrous material is, for example, a material having an aspect ratio of 5 or more, 20 or more, or 50 or more. The first fibrous material is, for example, a material having an aspect ratio of 5 to 1000, 20 to 1000, or 50 to 1000. The first fibrous material is, for example, an insulating material. Since the first fibrous material is an insulating material, a short circuit between the positive electrode (30) and the negative electrode (20) caused by lithium dendrites, etc., generated during the charging and discharging process of the lithium secondary battery (1) can be effectively prevented. The first fibrous material includes, for example, at least one selected from pulp fibers, insulating polymer fibers, and ion-conductive polymer fibers. The strength of the matrix is ​​improved by the inclusion of a reinforcing material in the matrix. Therefore, the matrix can prevent excessive volume change during charging and discharging of the lithium secondary battery (1) and deformation of the lithium secondary battery. The reinforcing material included in the matrix includes, for example, a second fibrous material. Since the reinforcing material includes the second fibrous material, the strength of the matrix can be increased more uniformly. The second fibrous material is, for example, a material having an aspect ratio of 3 or more, 5 or more, or 10 or more.The first fibrous material is, for example, a material having an aspect ratio of 3 to 100, 5 to 100, or 10 to 100. The second fibrous material is, for example, a flame-retardant material. Since the second fibrous material is a flame-retardant material, it can effectively suppress ignition due to thermal runaway occurring during the charging / discharging process of a lithium secondary battery (1) or due to external impact. The second fibrous material is, for example, glass fiber, metal oxide fiber, ceramic fiber, or the like.

[0157] The flame-retardant inert member includes a filler in addition to a matrix. The filler may be disposed within the matrix, on the surface of the matrix, or on both the interior and the surface. The filler is, for example, an inorganic material. The filler included in the flame-retardant inert member is, for example, a moisture getter. The filler removes moisture remaining in the lithium secondary battery (1) by adsorbing moisture, for example, at a temperature below 100°C, thereby preventing deterioration of the lithium secondary battery (1). In addition, when the temperature of the lithium secondary battery (1) increases to 150°C or higher due to thermal runaway occurring during the charging / discharging process of the lithium secondary battery (1) or an external impact, the filler can release the adsorbed moisture, thereby effectively suppressing ignition of the lithium secondary battery (1). That is, the filler is, for example, a flame retardant. The filler is, for example, a metal hydroxide having moisture adsorption properties. The metal hydroxide contained in the filler is, for example, Mg(OH)2, Fe(OH)3, Sb(OH)3, Sn(OH)4, TI(OH)3, Zr(OH)4, Al(OH)3, or a combination thereof. The content of the filler contained in the flame-retardant inert member is, for example, 10 to 80 parts by weight, 20 to 80 parts by weight, 30 to 80 parts by weight, 40 to 80 parts by weight, 50 to 80 parts by weight, 60 to 80 parts by weight, or 65 to 80 parts by weight, based on 100 parts by weight of the flame-retardant inert member (4).

[0158] The flame-retardant inert member may further comprise, for example, a binder. The binder may comprise, for example, a curable polymer or a non-curable polymer. A curable polymer is a polymer that cures by heat and / or pressure. A curable polymer is, for example, a solid at room temperature. The flame-retardant inert member (40) comprises, for example, a heat-pressure curable film and / or a cured product thereof. The heat-pressure curable polymer is, for example, TSA-66 from Toray.

[0159] The flame-retardant inert member may additionally include other materials in addition to the above-described substrate, reinforcing material, filler, and binder. The flame-retardant inert member may further include one or more selected from among paper, an insulating polymer, an ion-conducting polymer, an insulating inorganic material, an oxide-based solid electrolyte, and a sulfide-based solid electrolyte. The insulating polymer may be, for example, an olefin-based polymer such as polypropylene (PP) or polyethylene (PE).

[0160] The density of the substrate or reinforcing material included in the flame-retardant inert material may be, for example, 10% to 300%, 10% to 150%, 10% to 140%, 10% to 130%, or 10% to 120% of the density of the composite positive electrode active material included in the positive electrode active material layer (12).

[0161] The inert member (40) is a member that does not contain an electrochemically active material, for example, an electrode active material. The electrode active material is a material that absorbs / releases lithium. The inert member (40) is a member made of a material other than the electrode active material and used in the relevant technical field.

[0162] [cathode]

[0163] According to one embodiment, the negative electrode (20) may include a lithium-compatible material. For example, the lithium-compatible material may be, for example, a negative electrode material capable of forming an alloy or compound with lithium. For example, since the negative electrode (20) includes a lithium-compatible material, an alloy with lithium or lithium metal may be deposited on the negative electrode when the lithium secondary battery is charged.

[0164] Referring to FIGS. 1 to 5, the negative electrode (20) includes a negative electrode current collector (21) and a first negative electrode active material layer (22) disposed on one surface of the negative electrode current collector.

[0165] [Cathode: Cathode active material]

[0166] Referring to FIGS. 1 to 5, the negative electrode (20) includes a first negative electrode active material layer (22). The first negative electrode active material layer (22) includes, for example, a negative electrode active material and a binder.

[0167] The negative electrode active material included in the first negative electrode active material layer (22) may include a lithium affinity material. The negative electrode active material included in the first negative electrode active material layer (22) has, for example, a particle shape. The average particle diameter of the negative electrode active material having a particle shape is, for example, 4 ㎛ or less, 3 ㎛ or less, 2 ㎛ or less, 1 ㎛ or less, 500 nm or less, 300 nm or less, or 100 nm or less. The average particle diameter of the negative electrode active material having a particle shape is, for example, 10 nm to 4 ㎛, 10 nm to 3 ㎛, 10 nm to 2 ㎛, 10 nm to 1 ㎛, 10 nm to 500 nm, 10 nm to 300 nm, or 10 nm to 100 nm. When the negative electrode active material has an average particle size within this range, reversible absorption and / or desorption of lithium can be facilitated during charge and discharge. The average particle size of the negative electrode active material is, for example, the median diameter (D50) measured using a laser particle size distribution analyzer.

[0168] For example, the lithium-affinity material includes at least one selected from a carbon-based negative electrode active material and a metal or metalloid negative electrode active material.

[0169] Carbon-based negative electrode materials include, for example, amorphous carbon, crystalline carbon, porous carbon, or a combination thereof.

[0170] The carbon-based negative electrode material is, in particular, amorphous carbon. Amorphous carbon includes, but is not limited to, carbon black (CB), acetylene black (AB), furnace black (FB), ketjen black (KB), and graphene, and any material classified as amorphous carbon in the relevant technical field is acceptable. Amorphous carbon is carbon that has no crystallinity or very low crystallinity, and is distinguished from crystalline carbon or graphite-based carbon.

[0171] The carbon-based negative electrode active material may be, for example, porous carbon. The porous carbon has a pore volume of, for example, 0.1 cc / g to 10.0 cc / g, 0.5 cc / g to 5 cc / g, or 0.1 cc / g to 1 cc / g. The porous carbon has an average pore diameter of, for example, 1 nm to 50 nm, 1 nm to 30 nm, or 1 nm to 10 nm. The porous carbon has a BET surface area of, for example, 100 m 2 / g to 3000 m 2 / g is.

[0172] The metal or metalloid negative electrode active material includes, but is not limited to, one or more selected from the group consisting of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn), and any metal or metalloid negative electrode active material that forms an alloy or compound with lithium in the relevant technical field may be used. For example, nickel (Ni) does not form an alloy with lithium and therefore is not a metal negative electrode active material.

[0173] The first negative electrode active material layer (22) includes a type of negative electrode active material among these negative electrode active materials, or includes a mixture of a plurality of different negative electrode active materials. For example, the first negative electrode active material layer (22) includes only amorphous carbon, or includes at least one selected from the group consisting of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn). Alternatively, the first negative electrode active material layer (22) includes a mixture of amorphous carbon and at least one selected from the group consisting of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn). The mixing ratio of the mixture of amorphous carbon and gold, etc., is a weight ratio, for example, 99:1 to 1:99, 10:1 to 1:2, 5:1 to 1:1, or 4:1 to 2:1, but is not necessarily limited to this range and is selected according to the required characteristics of the lithium secondary battery (1). When the negative electrode active material has this composition, the cycle characteristics of the lithium secondary battery (1) are further improved.

[0174] The negative electrode active material included in the first negative electrode active material layer (22) includes, for example, a mixture of first particles made of amorphous carbon and second particles made of a metal or a metalloid. The metal or metalloid includes, for example, gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn). Alternatively, the metalloid is a semiconductor. The content of the second particles is 1 to 99 wt%, 1 to 60 wt%, 8 to 60 wt%, 10 to 50 wt%, 15 to 40 wt%, or 20 to 30 wt% based on the total weight of the mixture. When the second particles have a content in this range, the cycle characteristics of, for example, a lithium secondary battery (1) are further improved.

[0175] Alternatively, the first negative electrode active material layer (22) includes a composite negative electrode active material. For example, the composite negative electrode active material may include a lithium-affinity material. For example, the composite negative electrode active material may include a carbon-based support as a lithium-affinity material and a metal-based negative electrode active material supported on the carbon-based support. Since the composite negative electrode active material has such a structure, the uneven distribution of the metal-based negative electrode active material within the first negative electrode active material layer can be prevented and a uniform distribution can be obtained. As a result, the cycle characteristics of the lithium secondary battery (1) including the first negative electrode active material layer (22) are further improved.

[0176] As a lithium affinity material, a metal-based negative electrode active material supported on a carbon-based support includes, for example, a metal, a metal oxide, a complex of a metal and a metal oxide, or a combination thereof. The metal includes, for example, gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), tellurium (Te), and zinc (Zn). The metal oxide includes, for example, gold (Au) oxide, platinum (Pt) oxide, palladium (Pd) oxide, silicon (Si) oxide, silver (Ag) oxide, aluminum (Al) oxide, bismuth (Bi) oxide, tin (Sn) oxide, tellurium (Te) oxide, and zinc (Zn) oxide. The metal oxide includes, for example, Au x O y (0 <x≤2, 0<y≤3), Pt x O y (0 <x≤1, 0<y≤2), Pd x O y (0 <x≤1, 0<y≤1), Si x O y (0 <x≤1, 0<y≤2), Ag x O y (0 <x≤2, 0<y≤1), Al x O y (0 <x≤2, 0<y≤3), Bi x O y (0 <x≤2, 0<y≤3), Sn x O y (0 <x≤1, 0<y≤2), Te x O y (0 <x≤1, 0<y≤3), Zn x O y (0 <x≤1, 0<y≤1) 또는 이들의 조합을 포함할 수 있다. 금속과 금속산화물의 복합체는 예를 들어 Au와 Au x O y (0 <x≤2, 0<y≤3)의 복합체, Pt와 Pt x O y (0 <x≤1, 0<y≤2)의 복합체, Pd와 Pd x O y(0 <x≤1, 0<y≤1)의 복합체, Si와 Si x O y (0 <x≤1, 0<y≤2)의 복합체, Ag 와 Ag x O y (0 <x≤2, 0<y≤1)의 복합체, Al과 Al x O y (0 <x≤2, 0<y≤3)의 복합체, Bi와 Bi x O y (0 <x≤2, 0<y≤3)의 복합체, Sn과 Sn x O y (0 <x≤1, 0<y≤2)의 복합체, Te과 Te x O y (0 <x≤1, 0<y≤3), Zn과 Zn x O y (0 <x≤1, 0<y≤1)의 복합체, 또는 이들의 조합을 포함할 수 있다.

[0177] According to one embodiment, the lithium-affinity material is a carbon-based support, for example, amorphous carbon. Amorphous carbon includes, but is not limited to, carbon black (CB), acetylene black (AB), furnace black (FB), ketjen black (KB), graphene, activated carbon, carbon nanofibers (CNF), carbon nanotubes (CNT), etc., and any material classified as amorphous carbon in the art is possible. Amorphous carbon is carbon that has no crystallinity or very low crystallinity, and is distinguished from crystalline carbon or graphite-based carbon. The carbonaceous material is, for example, a carbon-based negative electrode active material.

[0178] According to one embodiment, the composite negative electrode active material has, for example, a particle form. The particle size of the composite negative electrode active material having a particle form is, for example, 10 nm to 4 ㎛, 10 nm to 1 ㎛, 10 nm to 500 nm, 10 nm to 200 nm, or 10 nm to 100 nm. When the composite negative electrode active material has a particle size in this range, reversible absorption and / or desorption of lithium may be facilitated during charge and discharge. The metal-based negative electrode active material supported on the support may have, for example, a particle form. The particle size of the metal-based negative electrode active material may be, for example, 1 nm to 200 nm, 1 nm to 150 nm, 5 nm to 100 nm, or 10 nm to 50 nm. The carbon-based support may have, for example, a particle form. The particle size of the carbon-based support may be, for example, 10 nm to 2 ㎛, 10 nm to 1 ㎛, 10 nm to 500 nm, 10 nm to 200 nm, or 10 nm to 100 nm. By having a particle size in this range, the carbon-based support can be more uniformly arranged within the first negative electrode active material layer. The carbon-based support may be, for example, nanoparticles having a particle size of 500 nm or less. The particle sizes of the composite negative electrode active material, the particle sizes of the metal-based negative electrode active material, and the particle sizes of the carbon-based support are, for example, average particle sizes. The average particle size is, for example, the median diameter (D50) measured using a laser particle size distribution analyzer. Alternatively, the average particle size may be determined automatically using software, for example, from an electron microscope image, or manually by a manual method.

[0179] [Cathode: Binder]

[0180] The binder included in the first negative electrode active material layer (22) is, for example, styrene-butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, vinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, polymethyl methacrylate, etc., but is not necessarily limited thereto and any binder used in the relevant technical field may be used. The binder may be composed of a single binder or a plurality of different binders.

[0181] Since the first negative electrode active material layer (22) includes a binder, the first negative electrode active material layer (22) is stabilized on the negative electrode current collector (21). In addition, cracking of the first negative electrode active material layer (22) is suppressed despite changes in the volume and / or relative position of the first negative electrode active material layer (22) during the charge and discharge process. For example, if the first negative electrode active material layer (22) does not include a binder, the first negative electrode active material layer (22) can be easily separated from the negative electrode current collector (21). As the first negative electrode active material layer (22) is separated from the negative electrode current collector (21), the possibility of a short circuit occurring increases as the negative electrode current collector (21) comes into contact with the electrolyte layer (30) at the exposed portion of the negative electrode current collector (21). The first negative electrode active material layer (22) is manufactured by, for example, applying a slurry in which the material constituting the first negative electrode active material layer (22) is dispersed onto the negative electrode current collector (21) and drying the slurry. By including a binder in the first negative electrode active material layer (22), stable dispersion of the negative electrode active material in the slurry is possible. For example, when applying the slurry onto the negative electrode current collector (21) by screen printing, it is possible to suppress clogging of the screen (for example, clogging by aggregates of the negative electrode active material).

[0182] [Cathode: Other additives]

[0183] The first negative electrode active material layer (22) may further include additives used in conventional lithium secondary batteries (1), such as fillers, coating agents, dispersants, and ion conductive aids.

[0184] According to another embodiment, the first negative electrode active material layer (22) may further include the metal-organic framework described above.

[0185] [Cathode: Solid electrolyte]

[0186] The first negative electrode active material layer (22) may further include a solid electrolyte. The solid electrolyte may be, for example, a material selected from among the solid electrolytes included in the electrolyte layer (30). The solid electrolyte included in the first negative electrode active material layer (22) may act as a reaction site where lithium metal formation begins within the first negative electrode active material layer (22), a space where the formed lithium metal is stored, or a path for transferring lithium ions. The solid electrolyte may be omitted.

[0187] In the first negative electrode active material layer (22), the content of the solid electrolyte may be high, for example, in an area adjacent to the electrolyte layer (30), and low, for example, in an area adjacent to the negative electrode current collector (21). In the first negative electrode active material layer (22), the solid electrolyte may have a concentration gradient in which the concentration decreases, for example, from an area adjacent to the electrolyte layer (30) to an area adjacent to the negative electrode current collector (21).

[0188] [Cathode: First negative electrode active material layer]

[0189] The ratio (B / A) of the initial charge capacity (B) of the first negative electrode active material layer (22) and the initial charge capacity (A) of the positive electrode active material layer is 0.005 to 0.45. The initial charge capacity of the positive electrode active material layer (12) is the first open circuit voltage (1 st Li / Li from open circuit voltage) +The initial charge capacity of the first negative electrode active material layer (22) is determined at the maximum charging voltage. The initial charge capacity of the first negative electrode active material layer (22) is determined at the second open circuit voltage (2 nd Li / Li from open circuit voltage) + It is determined at 0.01 V.

[0190] The maximum charging voltage is determined by the type of composite cathode active material. The maximum charging voltage can be, for example, 1.5 V, 2.0 V, 2.5 V, 3.0 V, 3.5 V, 4.0 V, 4.2 V, or 4.3 V. For example, the maximum charging voltage of Li2S or Li2S composite is Li / Li + can be 2.5 V for Li2S or Li2S complex. For example, the maximum charging voltage of Li / Li +It can be 3.0 V for. The ratio (B / A) of the initial charge capacity (B) of the first negative electrode active material layer (22) and the initial charge capacity (A) of the positive electrode active material layer is, for example, 0.01 to 0.3, 0.01 to 0.2, or 0.05 to 0.1. The initial charge capacity (mAh) of the positive electrode active material layer (12) is obtained by multiplying the charge capacity density (charge specific capacity) (mAh / g) of the composite positive electrode active material by the mass (g) of the composite positive electrode active material in the positive electrode active material layer (12). When several types of composite positive electrode active materials are used, the charge capacity density × mass value is calculated for each composite positive electrode active material, and the sum of these values ​​is the initial charge capacity of the positive electrode active material layer (12). The initial charge capacity of the first negative electrode active material layer (22) is also calculated in the same way. The initial charge capacity of the first negative electrode active material layer (22) is obtained by multiplying the charge capacity density (mAh / g) of the negative electrode active material by the mass of the negative electrode active material in the first negative electrode active material layer (22). When several types of negative electrode active materials are used, the charge capacity density Х mass value is calculated for each negative electrode active material, and the sum of these values ​​is the initial charge capacity of the first negative electrode active material layer (22). The charge capacity density of each composite positive electrode active material and negative electrode active material can be measured using an all-solid-state half-cell using lithium metal as a counter electrode. The initial charge capacity of each of the positive electrode active material layer (12) and the first negative electrode active material layer (22) is obtained by multiplying the charge capacity density (mAh / g) of the negative electrode active material by the mass value of the negative electrode active material in the first negative electrode active material layer (22). 2 can be directly measured using an all-solid-state half-cell. For the positive electrode, the measurement is made from the first open circuit voltage (OCV) to the maximum charge voltage, for example, 3.0 V (vs. Li / Li +) can be performed for an operating voltage of up to 0.01 V for the cathode, for example, lithium metal, from the second open circuit voltage (OCV). For example, an all-solid-state half-cell having a cathode active material layer can measure a current of 0.1 mA / cm from the first open circuit voltage to 3.0 V. 2 The all-solid-state half-cell having the first negative active material layer is charged with a constant current of 0.1 mA / cm from the second open circuit voltage to 0.01 V. 2 It can be charged with a constant current. The current density during constant current charging is, for example, 0.2 mA / cm 2 , or 0.5 mA / cm 2 The all-solid-state half-cell having the positive electrode active material layer can be charged from the first open circuit voltage to, for example, 2.5 V, 2.0 V, 3.5 V, or 4.0 V. The maximum charge voltage of the positive electrode active material layer can be determined by the maximum voltage of the battery that satisfies the safety conditions according to JISC8712:2015 of the Japanese Standards Association.

[0191] If the initial charge capacity of the first negative electrode active material layer (22) is too small, the thickness of the first negative electrode active material layer (22) becomes very thin, so that lithium dendrites formed between the first negative electrode active material layer (22) and the negative electrode current collector (21) during repeated charge / discharge processes collapse the first negative electrode active material layer (22), making it difficult to improve the cycle characteristics of the lithium secondary battery (1). If the charge capacity of the first negative electrode active material layer (22) increases excessively, the energy density of the lithium secondary battery (1) decreases and the internal resistance of the lithium secondary battery (1) due to the first negative electrode active material layer (22) increases, making it difficult to improve the cycle characteristics of the lithium secondary battery (1).

[0192] The thickness of the first negative electrode active material layer (22) is, for example, 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, or 5% or less of the thickness of the positive electrode active material layer (12). The thickness of the first negative electrode active material layer (22) is, for example, 1 to 50%, 1 to 40%, 1 to 30%, 1 to 20%, 1 to 10%, or 1 to 5% of the thickness of the positive electrode active material layer (12). The thickness of the first negative electrode active material layer (22) is, for example, 1 µm to 20 µm, 2 µm to 15 µm, or 3 µm to 10 µm. If the thickness of the first negative electrode active material layer (22) is too thin, lithium dendrites formed between the first negative electrode active material layer (22) and the negative electrode current collector (21) collapse the first negative electrode active material layer (22), making it difficult to improve the cycle characteristics of the lithium secondary battery (1). If the thickness of the first negative electrode active material layer (22) increases excessively, the energy density of the lithium secondary battery (1) decreases and the internal resistance of the lithium secondary battery (1) due to the first negative electrode active material layer (22) increases, making it difficult to improve the cycle characteristics of the lithium secondary battery (1). If the thickness of the first negative electrode active material layer (22) decreases, for example, the initial charge capacity of the first negative electrode active material layer (22) also decreases.

[0193] [Cathode: Second negative electrode active material layer]

[0194] Referring to FIG. 3, the lithium secondary battery (1) further includes, after being charged, a second negative electrode active material layer (24) disposed, for example, between the negative electrode current collector (21) and the first negative electrode active material layer (22). The second negative electrode active material layer (24) is a metal layer containing lithium or a lithium alloy. The metal layer contains lithium or a lithium alloy. Therefore, since the second negative electrode active material layer (24) is a metal layer containing lithium, it functions as, for example, a lithium reservoir. The lithium alloy is, for example, a Li-Al alloy, a Li-Sn alloy, a Li-In alloy, a Li-Ag alloy, a Li-Au alloy, a Li-Zn alloy, a Li-Ge alloy, a Li-Si alloy, etc., but is not limited thereto, and any lithium alloy used in the art may be used. The second negative electrode active material layer (24) may be made of one of these alloys or lithium, or may be made of several types of alloys. The second negative electrode active material layer (24) is, for example, a plated layer. The second negative electrode active material layer (24) is deposited between the first negative electrode active material layer (22) and the negative electrode current collector (21), for example, during the charging process of a lithium secondary battery (1).

[0195] The thickness of the second negative electrode active material layer (24) is not particularly limited, but is, for example, 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. If the thickness of the second negative electrode active material layer (24) is too thin, it is difficult for the second negative electrode active material layer (24) to perform the role of a lithium reservoir. If the thickness of the second negative electrode active material layer (24) is too thick, the mass and volume of the lithium secondary battery (1) may increase, and the cycle characteristics of the lithium secondary battery (1) may rather deteriorate.

[0196] Alternatively, in the lithium secondary battery (1), the second negative electrode active material layer (24) may be disposed between the negative electrode current collector (21) and the first negative electrode active material layer (22), for example, before assembling the lithium secondary battery (1). When the second negative electrode active material layer (24) is disposed between the negative electrode current collector (21) and the first negative electrode active material layer (22) before assembling the lithium secondary battery (1), the second negative electrode active material layer (24) acts as a lithium reservoir because it is a metal layer containing lithium. For example, a lithium foil may be disposed between the negative electrode current collector (21) and the first negative electrode active material layer (22) before assembling the lithium secondary battery (1).

[0197] When the second negative electrode active material layer (24) is precipitated by charging after assembling the lithium secondary battery (1), the energy density of the lithium secondary battery (1) increases because the second negative electrode active material layer (24) is not included when assembling the lithium secondary battery (1). When charging the lithium secondary battery (1), the charging is performed in excess of the charging capacity of the first negative electrode active material layer (22). That is, the first negative electrode active material layer (22) is overcharged. At the beginning of charging, lithium is absorbed into the first negative electrode active material layer (22). The negative electrode active material included in the first negative electrode active material layer (22) forms an alloy or compound with the lithium ions that have moved from the positive electrode (10). When charging exceeds the capacity of the first negative electrode active material layer (22), for example, lithium is deposited on the back surface of the first negative electrode active material layer (22), that is, between the negative electrode current collector (21) and the first negative electrode active material layer (22), and a metal layer corresponding to the second negative electrode active material layer (24) is formed by the deposited lithium. The second negative electrode active material layer (24) is a metal layer mainly composed of lithium (i.e., metallic lithium). This result is obtained, for example, by the negative electrode active material included in the first negative electrode active material layer (22) including a material that forms an alloy or compound with lithium. During discharge, lithium in the first negative electrode active material layer (22) and the second negative electrode active material layer (24), that is, the metal layer, is ionized and moves toward the positive electrode (10). Therefore, it is possible to use lithium as the negative electrode active material in a lithium secondary battery (1). In addition, since the first negative electrode active material layer (22) covers the second negative electrode active material layer (24), it functions as a protective layer for the second negative electrode active material layer (24), i.e., the metal layer, and at the same time, it suppresses the precipitation and growth of lithium dendrites. Accordingly, it suppresses short circuit and capacity reduction of the lithium secondary battery (1), and consequently improves the cycle characteristics of the lithium secondary battery (1).In addition, when the second negative electrode active material layer (24) is placed by charging after assembling the lithium secondary battery (1), the negative electrode (20), i.e., the negative electrode current collector (21) and the first negative electrode active material layer (22) and the region between them are Li-free regions that do not contain lithium (Li) in the initial state or the state after complete discharge of the lithium secondary battery (1).

[0198] [Cathode: Negative current collector]

[0199] The negative electrode current collector (21) is composed of, for example, a material that does not react with lithium, i.e., does not form an alloy or a compound. The material constituting the negative electrode current collector (21) is, for example, copper (Cu), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), and nickel (Ni), but is not necessarily limited thereto, and any material that can be used as an electrode current collector in the relevant technical field can be used. The negative electrode current collector (21) may be composed of one type of the above-described metal, or may be composed of an alloy or a coating material of two or more types of metals. The negative electrode current collector (21) is, for example, in the form of a plate or foil.

[0200] Referring to FIG. 2, the lithium secondary battery (1) may further include a thin film (23) containing an element capable of forming an alloy with lithium on one surface of the negative electrode current collector (21). The thin film (23) is disposed between the negative electrode current collector (21) and the first negative electrode active material layer (22). The thin film (23) contains, for example, an element capable of forming an alloy with lithium. The element capable of forming an alloy with lithium includes, but is not limited to, gold, silver, zinc, tin, indium, silicon, aluminum, bismuth, etc., and any element capable of forming an alloy with lithium in the art may be used. The thin film (23) is composed of one of these metals or an alloy of several types of metals. By placing the thin film (23) on one surface of the negative electrode current collector (21), for example, the deposition shape of the second negative electrode active material layer (24) deposited between the thin film (23) and the first negative electrode active material layer (22) becomes flatter, and the cycle characteristics of the lithium secondary battery (1) can be further improved.

[0201] The thickness of the thin film (23) is, for example, 1 nm to 800 nm, 10 nm to 700 nm, 50 nm to 600 nm, or 100 nm to 500 nm. If the thickness of the thin film (23) is less than 1 nm, it may be difficult for the function of the thin film (23) to be exerted. If the thickness of the thin film (23) is excessively thick, the thin film (23) itself absorbs lithium, which reduces the amount of lithium precipitation from the negative electrode, thereby lowering the energy density of the all-solid-state battery and deteriorating the cycle characteristics of the lithium secondary battery (1). The thin film (23) may be disposed on the negative electrode current collector (21) by, for example, a vacuum deposition method, a sputtering method, a plating method, or the like, but is not necessarily limited to these methods, and any method capable of forming the thin film (23) in the relevant technical field may be used.

[0202] Although not shown in the drawing, the negative electrode current collector (21) may include, for example, a base film and a metal layer disposed on one or both sides of the base film. The base film may include, for example, a polymer. The polymer may be, for example, a thermoplastic polymer. The polymer may include, for example, polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polybutylene terephthalate (PBT), polyimide (PI), or a combination thereof. The polymer may be an insulating polymer. Since the base film includes an insulating thermoplastic polymer, when a short circuit occurs, the base film may soften or liquefy, thereby blocking battery operation and suppressing a rapid increase in current. The metal layer may include, for example, copper (Cu), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), or an alloy thereof. The negative electrode current collector (21) may additionally include a metal piece and / or a lead tab. For more specific details regarding the base film, metal layer, metal chip, and lead tab of the negative electrode collector (21), refer to the positive electrode collector (11) described above. By having this structure, the negative electrode collector (21) can reduce the weight of the negative electrode, and consequently, improve the energy density of the negative electrode and lithium secondary battery.

[0203] [Electrolyte layer]

[0204] [Electrolyte layer: electrolyte]

[0205] Referring to FIGS. 1 to 5, the electrolyte layer (30) includes an electrolyte disposed between the positive electrode (10) and the negative electrode (20). The electrolyte may include, for example, a solid electrolyte, a gel electrolyte, or a combination thereof.

[0206] The solid electrolyte may include, for example, a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a polymer solid electrolyte, or a combination thereof.

[0207] The solid electrolyte is, for example, a sulfide-based solid electrolyte. The sulfide-based solid electrolyte is, for example, Li2S-P2S5, Li2S-P2S5-LiX, where X is a halogen element, 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, n are positive numbers, Z is one of Ge, Zn or Ga, Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q , p, q are positive numbers, M is one of P, Si, Ge, B, Al, Ga In, Li 7-x PS 6-x Cl x , 0≤x≤2, Li 7-x PS 6-x Br x , 0≤x≤2, and Li 7-x PS 6-x I x, at least one selected from 0≤x≤2. The sulfide-based solid electrolyte is manufactured by treating starting materials such as Li2S and P2S5 by a melting rapid cooling method or a mechanical milling method. In addition, heat treatment may be performed after the treatment. The solid electrolyte may be amorphous, crystalline, or a mixture thereof. In addition, the solid electrolyte may be, for example, one containing sulfur (S), phosphorus (P), and lithium (Li) as at least constituent elements among the above-described sulfide-based solid electrolyte materials. For example, the solid electrolyte may be a material containing Li2S-P2S5. When using a sulfide-based solid electrolyte material containing Li2S-P2S5 to form a solid electrolyte, the mixing molar ratio of Li2S and P2S5 is, for example, in the range of Li2S:P2S5=20:80 to 90:10, 25:75 to 90:10, 30:70 to 70:30, 40:60 to 60:40.

[0208] The sulfide-based solid electrolyte may include, for example, an argyrodite type solid electrolyte represented by the following chemical formula 1:

[0209] <Chemical Formula 1>

[0210] Li + 12-n-x A n+ X 2- 6-x Y - x

[0211] In the above formula, A is P, As, Ge, Ga, Sb, Si, Sn, Al, In, Ti, V, Nb or Ta, X is S, Se or Te, Y is Cl, Br, I, F, CN, OCN, SCN or N3, and 1≤n≤5, 0≤x≤2. The sulfide-based solid electrolyte is, for example, Li 7-x PS 6-x Cl x , 0≤x≤2, Li 7-xPS 6-x Br x , 0≤x≤2, and Li 7-x PS 6-x I x , may be an argyrodite-type compound including at least one selected from 0≤x≤2. The sulfide-based solid electrolyte may be, for example, an argyrodite-type compound including at least one selected from Li6PS5Cl, Li6PS5Br, and Li6PS5I.

[0212] The density of the argyrodite-type solid electrolyte may be 1.5 to 2.0 g / cc. Since the argyrodite-type solid electrolyte has a density of 1.5 g / cc or more, the internal resistance of the lithium secondary battery is reduced, and penetration of the electrolyte layer by Li can be effectively suppressed.

[0213] Oxide solid electrolytes include, for example, 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, Li3PO4, Li x Ti y (PO4)3(0 <x<2, 0<y<3), Li x Al y Ti z (PO4)3(0 <x<2, 0<y<1, 0<z<3), Li1+x+y (Al, Ga) x (Ti, Ge) 2-x Si y P 3-y O 12 (0≤x≤1 0≤y≤1), Li x La y TiO3(0 <x<2, 0<y<3), Li2O, LiOH, Li2CO3, LiAlO2, Li2O-Al2O3-SiO2-P2O5-TiO2-GeO2, Li 3+x La3M2O 12 (M = Te, Nb, or Zr, 0≤x≤10), or a combination thereof. The oxide-based solid electrolyte is manufactured, for example, by a sintering method.

[0214] Oxide-based solid electrolytes include, for example, Li7La3Zr2O 12 (LLZO) and Li 3+x La3Zr 2-a M a O 12 (M doped LLZO, M=Ga, W, Nb, Ta, or Al, 0 <a<2, 0≤x≤10) 중에서 선택된 가넷계(Garnet-type) 고체전해질이다.

[0215] The polymer solid electrolyte may, for example, comprise a mixture of a lithium salt and a polymer, or a polymer having ion-conducting functional groups. The polymer solid electrolyte may be, for example, a polymer electrolyte that is solid at 25°C and 1 atm. The polymer solid electrolyte may not, for example, comprise a liquid.The polymer solid electrolyte comprises a polymer, and the polymer is, for example, polyethylene oxide (PEO), polyvinylidene fluoride (PVDF), vinylidene fluoride-hexafluoropropylene (PVDF-HFP), polyethylene oxide (PEO), poly(styrene-b-ethylene oxide) block copolymer (PS-PEO), poly(styrene-butadiene), poly(styrene-isoprene-styrene), poly(styrene-b-divinylbenzene) block copolymer, poly(styrene-ethylene oxide-styrene) block copolymer, polystyrene sulfonate (PSS), polyvinyl fluoride (PVF), polymethyl methacrylate (PMMA, poly(methylmethacrylate), polyethylene glycol (PEG), polyacrylonitrile (PAN), polytetrafluoroethylene (PTFE), polyethylenedioxythiophene (PEDOT), polypyrrole (PPY), Polyacrylonitrile (PAN), polyaniline, polyacetylene, Nafion, Aquivion, Flemion, Gore, Aciplex, Morgane ADP, sulfonated poly(ether ether ketone) (SPEEK), sulfonated poly(arylene ether ketone ketone sulfone) (SPAEKKS), sulfonated poly(aryl ether ketone) (SPAEK), poly[bis(benzimidazobenzisoquinolinones)] (SPBIBI), poly(styrene sulfonate) (PSS), lithium 9,10-Diphenylanthracene-2-sulfonate (lithium 9,10-diphenylanthracene-2-sulfonate, DPASLi. +) or a combination thereof, but is not limited thereto, and any lithium salt that can be used in polymer electrolytes in the relevant technical field is possible. The lithium salt can be any lithium salt that can be used in the relevant technical field. The lithium salt is, for example, LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiCF3SO3, Li(CF3SO2)2N, LiC4F9SO3, LiAlO2, LiAlCl4, LiN(C x F 2x+1 SO2)(C y F 2y+1 SO2) (x and y are each 1 to 20), LiCl, LiI or a mixture thereof, etc. The polymer included in the polymer solid electrolyte may be, for example, a compound including 10 or more, 20 or more, 50 or more or 100 or more repeating units. The weight average molecular weight of the polymer included in the polymer solid electrolyte may be, for example, 1000 Dalton or more, 10,000 Dalton or more, 100,000 Dalton or more or 1,000,000 Dalton or more.

[0216] A gel electrolyte is, for example, a polymer gel electrolyte. A gel electrolyte can have a gel state without containing a polymer, for example.

[0217] A polymer gel electrolyte may include, for example, a liquid electrolyte and a polymer, or an organic solvent and a polymer having an ion-conducting functional group. The polymer gel electrolyte may be, for example, a polymer electrolyte that is in a gel state at 25°C and 1 atm. The polymer gel electrolyte may, for example, have a gel state without containing a liquid. The liquid electrolyte used in the polymer gel electrolyte may be, for example, an ionic liquid, a mixture of a lithium salt and an organic solvent; a mixture of a lithium salt and an organic solvent; a mixture of an ionic liquid and an organic solvent; or a mixture of a lithium salt, an ionic liquid, and an organic solvent. The polymer used in the polymer gel electrolyte may be selected from among the polymers used in solid polymer electrolytes. The organic solvent may be selected from among the organic solvents used in liquid electrolytes. The lithium salt may be selected from among the lithium salts used in solid polymer electrolytes. An ionic liquid refers to a salt that has a melting point below room temperature, is composed solely of ions, and is liquid at room temperature or a molten salt at room temperature. The ionic liquid comprises, for example, a) one or more cations selected from ammonium, pyrrolidinium, pyridinium, pyrimidinium, imidazolium, piperidinium, pyrazolium, oxazolium, pyridazinium, phosphonium, sulfonium, triazolium and mixtures thereof, and b) BF4. - , PF6 - , AsF6 - , SbF6 - , AlCl4 - , HSO4 - , ClO4 - , CH3SO3 - , CF3CO2 - , Cl - , Br - , I - , BF4 - , SO4 - , CF3SO3 - , (FSO2)2N - , (C2F5SO2)2N - , (C2F5SO2)(CF3SO2)N - , and (CF3SO2)2N -It may include at least one selected from compounds containing at least one anion selected from. The polymer solid electrolyte may form a polymer gel electrolyte by being impregnated in a liquid electrolyte, for example, in a secondary battery. The polymer gel electrolyte may further include inorganic particles. The polymer included in the polymer gel electrolyte may be, for example, a compound containing 10 or more, 20 or more, 50 or more, or 100 or more repeating units. The weight average molecular weight of the polymer included in the polymer gel electrolyte may be, for example, 500 Dalton or more, 1000 Dalton or more, 10,000 Dalton or more, 100,000 Dalton or more, or 1,000,000 Dalton or more.

[0218] [Electrolyte layer: binder]

[0219] The electrolyte layer (30) may include, for example, a binder. The binder included in the electrolyte layer (30) is not limited to, but may include, for example, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, etc., and any binder used in the relevant technical field may be used. The binder of the electrolyte layer (30) may be the same as or different from the binder included in the positive electrode active material layer (12) and the negative electrode active material layer (22). The binder may be omitted.

[0220] The binder content included in the electrolyte layer (30) is 0.1 to 10 wt%, 0.1 to 5 wt%, 0.1 to 3 wt%, 0.1 to 1 wt%, 0 to 0.5 wt%, or 0 to 0.1 wt% with respect to the total weight of the electrolyte layer (30).

[0221] [Electrolyte layer: metal-organic framework]

[0222] According to one embodiment, the electrolyte layer (30) may include the metal-organic framework described above.

[0223] The content of the metal organic structure in the electrolyte layer (30) is 0.1 to 50 parts by weight, for example, 0.1 to 20 parts by weight, for example, 1 to 10 parts by weight, for example, 1 to 5 parts by weight, based on 100 parts by weight of the electrolyte layer (30). When the content of the metal organic structure in the electrolyte layer (30) is within the above range, hydrogen sulfide generated in the lithium secondary battery is well captured inside the metal organic structure, so that problems caused by hydrogen sulfide generation can be prevented in advance.

[0224] [Method for producing metal-organic frameworks]

[0225] A metal-organic framework can be prepared by hydrothermal synthesis, microwave-assisted synthesis, ultrasonic synthesis, or electrochemical synthesis using a metal-organic framework composition comprising a metal ion precursor, an organic ligand precursor, and a solvent. In the composition, the organic ligand precursor and the metal ion precursor are used in stoichiometric amounts.

[0226] As the metal ion precursor, titanium isopropoxide, titanium ethoxide, titanium butoxide, aluminum nitrate, etc. are used, and as the organic ligand precursor, 1,4-benzenedicarboxylic acid, 1,3,5-benzenetricarboxylic acid, biphenyldicarboxylic acid, triphenyldicarboxylic acid, etc. are used. And as the solvent, ethanol, N,N-dimethylformamide, tetrahydrofuran, methyl ethyl ketone, acetonitrile, methylene chloride, or a mixture thereof can be used. The content of the solvent is 100 to 3,000 parts by weight based on 100 parts by weight of the metal organic framework.

[0227] In order to obtain a metal-organic framework having a uniform size represented by the above formula 1, when preparing a metal-organic framework composition, the organic ligand precursor is used in an amount exceeding the stoichiometric amount relative to the amount of the metal ion precursor. For example, the amount of the organic ligand precursor may be 1.3 to 100 mol, for example, 1.5 to 50 mol, specifically 1.3 to 20 mol, based on 1 mol of the metal ion precursor. When the organic ligand precursor is used in the above range, the metal-organic framework is evenly dispersed in the ion-conducting polymer matrix for forming the polymer electrolyte, so that a polymer electrolyte having excellent ion conductivity can be obtained without deteriorating the mechanical properties of the polymer electrolyte.

[0228] According to an embodiment, the above-described metal-organic framework can be obtained by heat-treating the above-described metal-organic framework composition at 50 to 500°C and performing a work-up process. Here, the heat-treatment conditions are not limited to the conditions described above.

[0229] It is also possible to further heat treat the reaction product obtained in the above process at 100 to 1200°C as needed.

[0230] The above metal-organic framework is not limited to a specific form and may be provided in the form of, for example, powder, thin film, membrane, pellet, slurry, paste, paint, bead, honeycomb, mesh, fiber, corrugated sheet, rotor, etc.

[0231] In one embodiment, the metal-organic framework in the positive electrode active material layer can be confirmed through X-ray analysis, thermogravimetric analysis, etc. of the positive electrode active material layer. Since the metal-organic framework has a metal oxide form in which pores are regularly arranged, the main peak appears at a low angle of 10 degrees or less, for example, 5 degrees or less, for example, 3 degrees or less as a result of X-ray diffraction analysis. The main peak is a diffraction characteristic resulting from the structure in which pores are regularly arranged. In addition, the presence and content of the metal-organic framework in the positive electrode active material layer can be confirmed through thermogravimetric analysis. In addition, the cross-section of the sample can be obtained through FIB, and the presence of nano-sized metal-organic frameworks can be confirmed through elemental analysis.

[0232] The present invention is explained in more detail through the following examples and comparative examples. However, the examples are intended to illustrate the present invention and are not intended to limit the scope of the present invention.

[0233] Manufacturing Example 1: Manufacturing of metal-organic framework (Ti8O8(OH)4{O2C-C6H4-CO2}6)(Ti-MOF)

[0234] Titanium isopropoxide and 1,4-benzene dicarboxylic acid were mixed in a mixed solvent of methanol and N,N-dimethylformamide at a volume ratio of 9:1 to obtain a mixture. The contents of titanium isopropoxide and 1,4-benzene dicarboxylic acid in this mixture were stoichiometrically controlled to obtain the target product Ti8O8(OH)4{O2C-C6H4-CO2}6. The total content of the mixed solvent was adjusted to approximately 150 times the weight of titanium isopropoxide.

[0235] The above mixture was heat treated at about 150°C for 24 hours.

[0236] After the reaction was completed, the resulting reaction product was cooled to room temperature (20-25°C). The cooled product was then washed with methanol and N,N-dimethylformamide, respectively. After the washing process, the product was dried at approximately 120°C for 24 hours to produce Ti8O8(OH)4{O2C-C6H4-CO2}6) (hereinafter referred to as TiMOF).

[0237] Evaluation Example 1: Dynamic Laser Scattering Analysis

[0238] The diameter distribution of MOF primary particles manufactured according to Manufacturing Example 1 was observed using dynamic laser scattering (DLS). The results are shown in Table 1 below. The dynamic laser scattering device used for the observation was HORIBA's LA-950.

[0239] Classification Average particle size (μ) (μm) Standard deviation (σ) F (σ2 / μ) Manufacturing example 10.126340.03440.12204

[0240] In the above Table 1, F(σ2 / μ) is a factor representing the diameter distribution of the metal-organic framework primary particles. The σ2 represents the variance of the metal-organic framework primary particles, and the variance corresponds to a value corresponding to the square of the standard deviation of the average particle diameter of the metal-organic framework primary particles, and μ represents the average particle diameter of the metal-organic framework primary particles.

[0241] Referring to Table 1 above, the factor F representing the diameter distribution of the primary particles of the metal-organic framework according to Manufacturing Example 1 shows a value less than 1.0.

[0242] In addition, through SEM and dynamic laser scattering analysis results, it was confirmed that a Ti-based nano metal-organic structure with a uniform shape and an average size of approximately 120 nm was synthesized.

[0243] Evaluation Example 2: Pore Characteristics Analysis (Nitrogen Adsorption / Desorption Curve)

[0244] A nitrogen adsorption experiment was performed on the metal-organic framework according to Manufacturing Example 1 after degassing at 150°C for 24 hours under vacuum. In the nitrogen adsorption experiment, nitrogen was adsorbed and desorbed on the powder of the metal-organic framework, and the specific surface area and pore volume of the metal-organic framework were calculated from the difference in the amount of nitrogen adsorbed and desorbed, and the pore size distribution was obtained, from which the average pore size was calculated. The nitrogen adsorption device used for the above observation was BELSORP-max from BEL.

[0245] Specifically, the specific surface area of ​​pores was calculated within the relative nitrogen pressure (P / P0) range of 0 to 1.0 using the BET (Brunauer-Emmett-Teller) method from the nitrogen adsorption-desorption isotherm obtained from the nitrogen adsorption experiment. The results are shown in Table 2.

[0246] Specific surface area (m) 2 / g) pore volume (cm) 3 / g) Pore size (Å) Manufacturing example 111200.99243.5598

[0247] Referring to Table 2 above, it can be confirmed that the metal-organic framework according to Manufacturing Example 1 has a mesoporous structure with a specific surface area of ​​1000 m2 / g or more.

[0248] (Manufacturing of positive and secondary batteries)

[0249] Example 1

[0250] (Polar electrode manufacturing)

[0251] A Li2S-LiI-CNF composite was prepared as a cathode active material. Li6PS5Cl (D50=3.0 μm, crystalline) in the form of argyrodite was prepared as a solid electrolyte. PTFE was prepared as a binder. These materials were mixed in a weight ratio of composite cathode active material: solid electrolyte: binder = 60:40:1.2 to prepare a cathode mixture. The cathode mixture was obtained by dry mixing using a thinky mixer.

[0252] The positive electrode was manufactured by placing the positive electrode active material mixture on one side of a positive electrode current collector made of aluminum foil coated on one side and plate pressing at a pressure of 200 MPa for 10 minutes. The thickness of the positive electrode was approximately 120 μm. The thickness of the positive electrode active material layer was approximately 100 μm, and the thickness of the carbon-coated aluminum foil was approximately 20 μm. The areas of the positive electrode active material layer and the positive electrode current collector were the same.

[0253] (Cathode manufacturing)

[0254] A 10 ㎛ thick SUS foil was prepared as a negative electrode collector. Carbon black (CB) with a primary particle diameter of approximately 30 nm and silver (Ag) particles with an average particle diameter of approximately 60 nm were prepared as negative electrode active materials.

[0255] A mixed powder of 4 g of carbon black (CB) and silver (Ag) particles in a weight ratio of 3:1 was placed in a container, and 4 g of an NMP solution containing 7 wt% of PVDF binder (Kureha #9300) was added thereto to prepare a mixed solution. A slurry was prepared by stirring the mixed solution while adding NMP little by little to the prepared mixed solution. The prepared slurry was applied to a SUS sheet using a bar coater, dried in air at 80°C for 10 minutes, and then vacuum-dried at 40°C for 10 hours to prepare a laminate. The prepared laminate was cold roll pressed to flatten the surface, thereby preparing a negative electrode having a first negative electrode active material layer / negative electrode current collector structure. The thickness of the first negative electrode active material layer was approximately 15 μm. The areas of the first negative electrode active material layer and the negative electrode current collector were the same.

[0256] (Manufacturing of solid electrolyte layer)

[0257] Li6PS5Cl solid electrolyte in the form of argyrodite crystals (D 50 =3.0 mm, crystalline), a mixture was prepared by adding 1.5 parts by weight of an acrylic binder to 98.5 parts by weight of a solid electrolyte. Octyl acetate was added to the prepared mixture and stirred to prepare a slurry. The prepared slurry was applied using a bar coater onto a 15 μm thick nonwoven fabric placed on a 75 μm thick PET substrate, and dried in air at 80°C for 10 minutes to prepare a laminate. The prepared laminate was vacuum-dried at 80°C for 2 hours to prepare a solid electrolyte layer.

[0258] (inert absence)

[0259] A Ti-MOF was prepared according to Manufacturing Example 1 using a metal-organic framework. A slurry containing the metal-organic framework according to Manufacturing Example 1, pulp fiber (cellulose fiber), glass fiber, aluminum hydroxide (Al(OH)3), an acrylic binder, and a solvent was formed into a gasket shape, and then the solvent was removed to manufacture a flame-retardant inert member.

[0260] The weight ratio of the metal-organic framework, pulp fiber (cellulose fiber), glass fiber, aluminum hydroxide (Al(OH)3), and acrylic binder was 5:20:8:70:2. The thickness of the inert material was 120 ㎛.

[0261] Before placing the manufactured flame-retardant inert material on the solid electrolyte layer, moisture, etc. of the flame-retardant inert material was removed by vacuum heat treatment at 80°C for 5 hours.

[0262] (Manufacturing of lithium secondary batteries)

[0263] A solid electrolyte layer was placed on the negative electrode such that the first negative electrode active material layer was in contact with the solid electrolyte layer, and a positive electrode was placed on the solid electrolyte layer. A laminate was prepared by placing a gasket surrounding the positive electrode and in contact with the solid electrolyte layer. The thickness of the gasket was approximately 120 ㎛. The above-mentioned flame-retardant inert material was used as the gasket. The gasket was placed so as to be in contact with the side surface of the positive electrode and the solid electrolyte layer. The positive electrode was placed at the center of the solid electrolyte layer, and the gasket was placed so as to surround the positive electrode and extend to the end of the solid electrolyte layer. The area of ​​the positive electrode was approximately 90% of the area of ​​the solid electrolyte layer, and the gasket was placed over the entire remaining 10% of the area of ​​the solid electrolyte layer where the positive electrode was not placed.

[0264] 85 prepared laminates oThe solid electrolyte layer was plate-pressed at 500 MPa for 30 min at C. This pressurization process sintered the solid electrolyte layer, thereby improving battery characteristics. The thickness of the sintered solid electrolyte layer was approximately 45 ㎛. The density of the Li6PS5Cl solid electrolyte, which was an argyrodite-type crystal contained in the sintered solid electrolyte layer, was 1.6 g / cc. The area of ​​the solid electrolyte layer was the same as that of the negative electrode.

[0265] A pressurized laminate was placed in a pouch and vacuum-sealed to manufacture a lithium secondary battery. Portions of the positive and negative current collectors were extended outside the sealed battery to serve as positive and negative terminals.

[0266] Example 2

[0267] A lithium secondary battery was manufactured in the same manner as Example 1, except that the pressurized laminate was prepared, the metal-organic framework according to Manufacturing Example 1 was placed in a pouch together with the pressurized laminate, and vacuum-sealed to manufacture a lithium secondary battery.

[0268] Example 3

[0269] In the manufacture of solid electrolyte, Li6PS5Cl solid electrolyte (D) which is an argyrodite type crystal compared to Example 1 50 =3.0 mm, crystalline) 90 parts by weight, 8.5 parts by weight of Ti-MOF according to Manufacturing Example 1 as a metal-organic framework, and an acrylic binder were added to prepare a mixture, and a lithium secondary battery was manufactured in the same manner as in Example 1, except that a solid electrolyte was manufactured therefrom.

[0270] Example 4

[0271] In the manufacture of the inert member, no metal organic structure was added compared to Example 1, and a slurry was prepared by mixing pulp fiber (cellulose fiber), glass fiber, aluminum hydroxide (Al(OH)3), and acrylic binder in a weight ratio of 20:8:70:2.

[0272] A lithium secondary battery was manufactured in the same manner as Example 1, except that the pressurized laminate was prepared, the metal-organic framework according to Manufacturing Example 1 was placed in a pouch together with the pressurized laminate, and vacuum-sealed to manufacture a lithium secondary battery.

[0273] Comparative Example 1

[0274] A lithium secondary battery was manufactured in the same manner as in Example 1, except that a metal-organic framework was not added when manufacturing an inert member, and a slurry was prepared by mixing pulp fiber (cellulose fiber), glass fiber, aluminum hydroxide (Al(OH)3), and an acrylic binder in a weight ratio of 20:8:70:2 to prepare an inert member.

[0275] Evaluation Example 3: Analysis of hydrogen sulfide production

[0276] Lithium secondary batteries were charged and discharged according to Examples 1 to 4 and Comparative Example 1, and the maximum amount of hydrogen sulfide generated per hour and the amount of hydrogen sulfide generated and accumulated over 1 hour from the lithium secondary batteries were measured. The analyzer used to measure the amount of hydrogen sulfide generated and accumulated was AIOBIO's Breathview. The analysis results are shown in Table 3 below.

[0277] MOF InclusionMaximum Hydrogen Sulfide Generation Per HourAccumulated Hydrogen Sulfide Generation in 1 HourInert AbsenceElectrolyte Pouch Empty SpaceExample 1IncludedNotIncludedNotIncluded3.1 ppm4.01 μLExample 2NotIncludedNotIncludedIncluded3.2 ppm4.25 μLExample 3IncludedNotIncluded2.6 ppm3.8 μLExample 4IncludedNotIncluded3.0 ppm3.98 μLComparative Example 1NotIncludedNotIncluded7.8 ppm9.01 μL

[0278] As shown in Table 3, the lithium secondary batteries according to Examples 1 to 4 showed a reduced amount of hydrogen sulfide generation compared to the lithium secondary battery of Comparative Example 1.

[0279] [Explanation of symbols]

[0280] 1 lithium secondary battery 10 anodes

[0281] 11. Cathode current collector 12. Cathode active material layer

[0282] 20 Cathode 21 Cathode current collector

[0283] 22 First negative electrode active material layer 23 Thin film

[0284] 24 Second negative electrode active material layer 30 Electrolyte layer

[0285] 40 Inert Absences

Claims

1. A cathode containing lithium sulfur (Li2S); anode; An electrolyte layer disposed between the anode and the cathode; and A lithium secondary battery comprising a metal-organic framework.

2. In paragraph 1, The above lithium secondary battery includes an inactive member disposed on one side of the positive electrode, A lithium secondary battery, wherein the inactive member comprises the metal-organic framework.

3. In paragraph 1, A lithium secondary battery, wherein the size of the metal-organic framework is 1 nm to 1 μm.

4. In paragraph 1, A lithium secondary battery, wherein the size of the metal organic framework has a uniform diameter distribution represented by the following formula 1: [Formula 1] 0.0 < σ2 / μ < 1.0 In the above equation 1, σ2 represents the variance of multiple primary particles measured using dynamic laser scattering (DLS), and μ represents the average particle diameter of multiple primary particles.

5. In paragraph 1, A positive electrode for a lithium secondary battery, wherein the metal-organic framework is a porous crystalline compound comprising a metal ion of Group 2 to Group 15 or a metal ion cluster of Group 2 to Group 15 and an organic ligand chemically bonded to the metal ion or the metal ion cluster.

6. In paragraph 5, The above group 2 to group 15 metal ions are cobalt (Co), nickel (Ni), molybdenum (Mo), tungsten (W), ruthenium (Ru), osdium (Os), cadmium (Cd), beryllium (Be), calcium (Ca), barium (Ba), strontium (Sr), iron (Fe), manganese (Mn), chromium (Cr), vanadium (V), aluminum (Al), titanium (Ti), zirconium (Zr), copper (Cu), zinc (Zn), magnesium (Mg), hafnium (Hf), niobium (Nb), tantalum (Ta), rhenium (Re), rhodium (Rh), iridium (Ir), palladium (Pd), platinum (Pt), silver (Ag), scandium (Sc), yttrium (Y), indium (In), thallium (Tl), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), arsenic (As), At least one selected from antimony (Sb) and bismuth (Bi), The above organic ligands are aromatic dicarboxylic acids, aromatic tricarboxylic acids, imidazole compounds, tetrazoles, 1,2,3-triazole, 1,2,4-triazole, pyrazole, aromatic sulfonic acid, aromatic phosphoric acid, aromatic sulfinic acid, aromatic phosphinic acid, bipyridine, amino group, imino group, amide group, methandithioic acid (-CS2H) group, methandithioic acid anion (-CS2 - ) A positive electrode for a lithium secondary battery, the positive electrode being a group derived from at least one compound having at least one functional group selected from a pyridine group and a pyrazine group.

7. In paragraph 1, The above metal-organic framework is a cathode for a lithium secondary battery, represented by the following chemical formula 1: [Chemical Formula 1] M m O k X l L p In the above chemical formula 1, M is Ti 4+ , Zr 4+ , Mn 4+ , Si 4+ , Al 3+ , Cr 3+ , V 3+ , Ga 3+ , Mn 3+ , Zn +3 , Mn 2+ , Mg 2+ , Fe 2+ , Fe 3+ and Cu +2 At least one selected from the group consisting of, m is an integer from 1 to 10, k is 0 or an integer from 1 to 10, l is 0 or an integer from 1 to 10, p is an integer from 1 to 10, X is OH - , Cl - , F - , I - , Br - , SO4 2- , NO3 - , ClO4 - , PF6 - , BF3 - , -(COO) n - , R 1 -(S03) n - or R 1 -(PO3) n - And, R 1 is at least one selected from hydrogen and C1-C30 alkyl groups, n is an integer from 1 to 4; L is a ligand containing a radical R comprising q carboxylate groups (*COO-#), q is an integer from 1 to 6, * indicates a position at which R is bonded to the carboxylate group, # indicates a position at which the metal ion M is bonded to the carboxylate group, and R is a substituted or unsubstituted C1-C30 alkyl, a substituted or unsubstituted C2-C30 alkenyl, a substituted or unsubstituted C2-C30 alkynyl, a substituted or unsubstituted mono C1-C30 aryl, and a polycyclic C1-C30 Aryl, substituted or unsubstituted mono C1-C30 Heteroaryl and polycyclic C1-C30 Selected from heteroaryl.

8. In paragraph 1, A cathode for a lithium secondary battery, wherein the metal-organic framework is a compound represented by the following chemical formula 2: [Chemical formula 2] M' m O k X' l L' p In the above chemical formula 2, M' is Ti 4+ , Zr 4+ , V 3+ , Zn +3 , Fe 2+ , Fe 3+ and Cu +2 One or more selected from among L'은 C6H4(CO2 - )2(terephthalate), C2H2(CO2 - )2(fumarate), C4H4(CO2 - )2(muconate), C5H3S(CO2 - )2(2,5-thiophenedicarboxylate), C6H2N2(CO2)2(2,5-pyrazine dicarboxylate), C2H4(CO2 - )2(succinate), C3H6(CO2 - )2(glutarate), C4H8(CO2 - )2adipate, C 10 H6(CO2 - )2(naphtalene-2,6-dicarboxylate), C 12 H8(CO2 - )2(biphenyl-4,4’-dicarboxylate), C 12 H8N2(CO2 - )2(azobenzenedicarboxylate), C6H3(CO2 - )3(benzene-1,2,4-tricarboxylate), C6H3(CO2 - )3(benzene-1,3,5-tricarboxylate), C 24 H 15 (CO2 - )3(benzene-1,3,5-tribenzoate), C6H2(CO2 - )4(benzene-1,2,4,5-tetracarboxylate, C 10 H4(CO2 - )4(naphtalene-2,3,6,7-tetracarboxylate), C 10 H4(CO2 - )4(naphtalene-1,4,5,8-tetracarboxylate) 및 C 12 H6(CO2 - )4(biphenyl-3,5,3′,5′-tetracarboxylate) is at least one selected from the group consisting of, X' is OH - , Cl - , F - , CH3COO - , PF6 - and ClO4 - One or more selected from among m is an integer from 1 to 8; k is 0 or an integer from 1 to 8; l is 0 or an integer from 1 to 8; p is an integer from 1 to 8.

9. In paragraph 1, The above metal organic framework is Ti8O8(OH)4[O2C-C6H4-CO2] 6, Ti8O8(OH)4[O2C-C6H3(NH2)-CO2]6, VO[C6H4(CO2)2], Al(OH)[C6H4(CO2)2], Cr(OH)[C6H4(CO2)2], Al(OH)[C 10 H6(CO2)2], Al1O(OH) 18 (H2O)3[C6H3-(CO2)3]6.nH2O, Cr3OX l [C6H4(CO2)2]3(X=H, OH - , Cl - , F - , CH3COO - , PF6 - and ClO4 - one or more selected from, and l is 0 or an integer from 1 to 8), Cr3OX l [C 12 H8(CO2)2]3(X=H, OH - , Cl - , F - , CH3COO - , PF6 - and ClO4 - one or more selected from, and l is 0 or an integer from 1 to 8), Cr3OX l [C6H3(CO2)3]3(X=H, OH - , Cl - , F - , CH3COO - , PF6 - and ClO4 - one or more selected from, and l is 0 or an integer from 1 to 8), Al8(OH) 15 (H2O)3[C6H3(CO2)3]3, V3OX l [C6H3(CO2)3]3(X=H, OH - , Cl - , F - , CH3COO - , PF6 - and ClO4 - A cathode for a lithium secondary battery, wherein at least one selected from the group consisting of ZrO[C6H4(CO2)2], and Ti8O8(OH)4[O2C-C6H3(NH2)-CO2]6.

10. In paragraph 1, A cathode for a lithium secondary battery, wherein the pore size of the metal-organic framework is 5 nm or less.

11. In paragraph 1, The above positive electrode comprises a positive electrode current collector; and a positive electrode active material layer disposed on the positive electrode current collector, A cathode for a lithium secondary battery, wherein the cathode active material layer comprises lithium sulfur (Li2S) and an ion-conductive lithium salt.

12. In paragraph 11, The above ion-conducting lithium salt is a binary compound or a ternary compound, The above binary compound comprises LiI, LiBr, LiCl, LiF, LiH, Li2O, Li2Se, Li2Te, Li3N, Li3P, Li3As, Li3Sb, Li3Al2, LiB3 or a combination thereof, A cathode for a lithium secondary battery, wherein the ternary compound comprises Li3OCl, LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiAlO2, LiAlCl4, LiNO3, Li2CO3, LiBH4, Li2SO4, Li3BO3, Li3PO4, Li4NCl, Li5NCl2, Li3BN2 or a combination thereof.

13. In paragraph 11, The above positive electrode active material layer further includes a carbon-based material, The above carbon-based material includes a carbon nanostructure, A cathode for a lithium secondary battery, wherein the carbon nanostructure comprises carbon nanofibers, carbon nanotubes, carbon nanobelts, carbon nanorods or a combination thereof.

14. In paragraph 11, A cathode for a lithium secondary battery, wherein the cathode active material layer further comprises a solid electrolyte.

15. In paragraph 14, The above solid electrolyte is a sulfide-based solid electrolyte, The above sulfide-based solid electrolyte is Li2S-P2S5, Li2S-P2S5-LiX, X is a halogen element, 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, n are positive numbers, Z is one of Ge, Zn or Ga, Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q , p, q are positive numbers, M is one of P, Si, Ge, B, Al, Ga In, Li 7-x PS 6-x Cl x , 0≤x≤2, Li 7-x PS 6-x Br x , 0≤x≤2, and Li 7-x PS 6-x I x A cathode for a lithium secondary battery, wherein at least one of , 0≤x≤2, is selected.

16. In paragraph 15, The above sulfide-based solid electrolyte includes an argyrodite-type solid electrolyte, The above argyrodite-type solid electrolyte comprises at least one selected from Li6PS5Cl, Li6PS5Br and Li6PS5I, A positive electrode for a lithium secondary battery, wherein the density of the above argyrodite-type solid electrolyte is 1.5 to 2.0 g / cc.

17. In paragraph 11, The above cathode current collector comprises a base film and a metal layer disposed on one or both sides of the base film, The above base film comprises a polymer, and the polymer comprises polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polybutylene terephthalate (PBT), polyimide (PI) or a combination thereof. A cathode for a lithium secondary battery, wherein the metal layer comprises 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.

18. In paragraph 1, A lithium secondary battery, wherein the electrolyte layer includes a solid electrolyte, a gel electrolyte, or a combination thereof.

19. In Article 18, A lithium secondary battery, wherein the electrolyte layer comprises a metal-organic framework.

20. In paragraph 1, A lithium secondary battery, wherein the negative electrode comprises a lithium-compatible material.

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