Lithium metal battery

Abstract

A lithium metal battery is presented, comprising: a cathode layer; an anode current collector; and an electrolyte disposed between the cathode layer and the anode current collector, wherein the cathode layer comprises: a cathode current collector; and a cathode active material layer disposed on one surface or both surfaces of the cathode current collector, and a lithium host layer is disposed on one surface of the anode current collector. The lithium host layer contains a binder and a lithium-philic metal-organic framework including a lithium-philic transition metal and an imidazole-based organic ligand, wherein the lithium-philic transition metal is zinc (Zn), gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), nickel (Ni), manganese (Mn), cobalt (Co), or a combination thereof, and the lithium-philic metal-organic framework has a pore volume of 0.01 cm3 / g or more. The lithium host layer further contains pores and the porosity of the lithium host layer is 40%-70%.

Description

lithium metal battery

[0001] It's about lithium metal batteries.

[0002] Lithium metal poses a risk of interfacial instability and fire hazards caused by uneven dendrite growth during battery charge / discharge. To address these issues, a method utilizing a lithium-storage host and electrolyte can be developed. By introducing a lithium-storage host with a large surface area and high mechanical strength and controlling the decomposition of the electrolyte, a stable solid-electrolyte interface (SEI) is formed on the electrode surface. This suppresses lithium dendrite growth and volume expansion, while simultaneously ensuring battery stability and cycle life.

[0003] Lithium metal batteries experience volume expansion and contraction during continuous charge / discharge cycles. Even if the anode is coated with a protective film, these volume changes can cause cracks and other deformations in the protective film, hindering long-life cycling. Lithium metal hosts provide a physical space to accommodate volume changes during charge / discharge, and their large surface area lowers the effective current density felt by lithium ions, thereby attracting attention as a way to suppress dendrite growth.

[0004] However, if these Li-hosts are not properly designed and manufactured, they can cause other problems. For example, since the Li-host structure does not basically contain lithium, there is a lack of a lithium source that can maintain a long charge-discharge cycle life. To overcome this problem, prelithiation of the Li-host can be attempted, but in most cases, the process is very complicated and results in a significant increase in cost. In addition, since the desired amount and desired space cannot be selectively filled during lithiation, it is difficult to function properly as a Li-host. For example, if the Li-host is completely lithiated and filled, there will be no empty space to accept lithium from the cathode, so it cannot function as a host.

[0005] One aspect is to provide a lithium metal battery with improved life characteristics and less capacity loss due to side reactions.

[0006] A lithium metal battery comprising a cathode layer; a cathode current collector; and an electrolyte disposed between the cathode layer and the cathode current collector.

[0007] The above positive electrode layer includes a positive electrode current collector and a positive electrode active material layer disposed on one or both sides of the positive electrode current collector,

[0008] It includes a lithium host layer disposed on one surface of the above negative electrode collector,

[0009] The above lithium host layer contains a lithium-affinity metal-organic framework including a lithium-affinity transition metal and an imidazole-based organic ligand and a binder,

[0010] The lithium-affinity transition metal is zinc (Zn), gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), nickel (Ni), manganese (Mn), cobalt (Co), or a combination thereof.

[0011] The pore volume of the above metal-organic framework is 0.01 cm 3 / g or more,

[0012] The above lithium host layer further includes pores,

[0013] A lithium metal battery is provided, wherein the porosity of the lithium host layer is 40% to 70%.

[0014] The processing volume of the lithium-affinity metal-organic framework structure is 0.01 to 1.0 cm 3 / g is.

[0015] The above lithium-affinity metal-organic framework structure is ZIF (Zeolitic-imidazolate)

[0016] It includes a carbon-based nanostructure based on a metal-organic framework. The particle size of the metal-organic framework is 50 nm to 3 μm, and the thickness of the lithium host layer is 50 nm to 1 μm.

[0017] A lithium precipitation layer may be absent between the negative electrode current collector and the lithium host layer.

[0018] The binder content in the above lithium host layer is 1 to 15 wt% based on the total weight of the lithium host layer.

[0019] It may include a first inactive member disposed on one side of the lithium host layer.

[0020] Lithium metal batteries according to one aspect contain a lithium host layer whose structure changes very little during continuous charging and discharging, so that capacity loss due to side reactions is small and life characteristics are improved.

[0021] Figure 1a shows the results of a scanning electron microscope (SEM) analysis of a ZIF-8 structure manufactured according to Manufacturing Example 1.

[0022] Figure 1b shows the SEM analysis results for the ZIF-8 structure manufactured according to Manufacturing Example 2.

[0023] Figure 2 shows the potential change according to capacity in a half-cell using a negative electrode current collector / lithium host layer laminate obtained according to Examples 1 and 2, and bare Cu of Comparative Example 1.

[0024] Figure 3 shows the life characteristics of the lithium metal batteries of Examples 2 and 3.

[0025] Figures 4 and 5 are cross-sectional views showing the structure of a lithium metal battery according to an embodiment.

[0026] <Explanation of key symbols in the drawing>

[0027] 10 Anode layer 11 Anode current collector

[0028] 12 positive electrode active material layers

[0029] 20 Cathode layer 21 Cathode current collector

[0030] 22 Lithium host layer 30 Solid electrolyte layer

[0031] 40 Inert member 41 Second inert member

[0032] 42 First inert member

[0033] Various embodiments are illustrated in the accompanying drawings. However, the present invention may be embodied in many different forms and should not be construed as limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art. Like reference numerals in the drawings indicate like elements.

[0034] 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.

[0035] Although the terms "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 used only 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 specification.

[0036] 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.

[0037] Spatially relative terms such as "below," "under," "bottom," "above," "above," and "top" 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 can be arranged in other orientations (rotated 90 degrees or otherwise rotated), and the spatially relative terms used herein can be interpreted accordingly.

[0038] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. Furthermore, it will be understood that terms defined in commonly used dictionaries should be interpreted to have a meaning consistent with their meaning within the context of the relevant art and the present disclosure, and not in an idealized or overly formal sense.

[0039] Exemplary embodiments are described herein 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 herein should not be construed as limited to the specific shapes of regions as depicted herein, 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.

[0040] "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.

[0041] Unless otherwise defined herein, particle size or particle diameter may be the average particle diameter or average major axis length. Particle size or particle diameter can be measured using a scanning electron microscope (SEM).

[0042] In this specification, “particle size” refers to the average diameter when the particle is spherical, and the average major axis length when the particle is non-spherical. Particle size can be measured using a particle size analyzer (PSA). “Particle size” is, for example, the average particle diameter. “Average particle diameter” is, for example, the median particle diameter, D50.

[0043] D50 is the size of the particle corresponding to 50% of the cumulative volume when calculated from the side of the particle having a small particle size in the size distribution of the particle measured by the laser diffraction method. D90 is the size of the particle corresponding to 90% of the cumulative volume when calculated from the side of the particle having a small particle size in the size distribution of the particle measured by the laser diffraction method. When measuring by the laser diffraction method, more specifically, after the particles to be measured are dispersed in a dispersion medium, they are introduced into a commercially available laser diffraction particle size measuring device (e.g., Microtrac MT 3000), and ultrasonic waves of approximately 28 kHz are irradiated at an output of 60 W, and the average particle diameter (D50) based on 50% of the particle size distribution in the measuring device can be calculated. In addition, D10 is the size of the particle corresponding to 10% of the cumulative volume when calculated from the side of the particle having a small particle size in the size distribution of the particle measured by the laser diffraction method.

[0044] In this specification, the average particle diameter and average major axis length can be measured using a scanning electron microscope (SEM). When measuring particle size using a scanning electron microscope, it is determined as the average value of at least 30 randomly selected particles of 1 μm or larger, excluding fine particles.

[0045] In this disclosure, “metal” includes both metals and metalloids such as silicon and germanium, in their elemental or ionic states.

[0046] In this disclosure, “alloy” means a mixture of two or more metals.

[0047] In this disclosure, "electrode active material" means an electrode material capable of undergoing lithiation and delithiation. In addition, in this disclosure, "positive electrode active material" means a positive electrode material capable of undergoing lithiation and delithiation, and "negative electrode active material" means a negative electrode material capable of undergoing lithiation and delithiation.

[0048] In the present disclosure, “lithiation” and “lithiating” mean a process of adding lithium to an electrode active material, and “delithiation” and “delithiating” mean a process of removing lithium from an electrode active material.

[0049] In the present disclosure, “lithium host” means a substrate or framework that accommodates lithium in an electrochemically pre-formed space.

[0050] In the present disclosure, “lithium host structure” means a structure composed of one or more lithium hosts.

[0051] In the present disclosure, “charging” and “charging” mean a process of providing electrochemical energy to a battery, and “discharging” and “discharging” mean a process of removing electrochemical energy from a battery.

[0052] In the present disclosure, “positive electrode” and “cathode” mean an electrode where electrochemical reduction and lithiation occur during a discharge process, and “negative electrode” and “anode” mean an electrode where electrochemical oxidation and delithiation occur during a discharge process.

[0053] In the present disclosure, pore size means the average pore size, and in the case where the pores are spherical, it means the average diameter, and in the case where the pores are non-spherical, it means the average major axis length.

[0054] In this specification, “pore size” is mainly measured using the mercury intrusion method, the gas adsorption method, or SEM. Gas adsorption methods include the BET (Brunauer, Emmett, Teller) method or the BJH (Barrett-Joyner-Halenda) method. In this specification, pore size refers to the average pore size. In the present disclosure, pore size can be measured using the BET method or can be measured using a scanning electron microscope (SEM). The SEM method evaluates pore size using image analysis. In the examples of the present disclosure, pore size is evaluated according to the BET (Brunauer, Emmett, Teller) method.

[0055] In the present disclosure, thickness means average thickness.

[0056] 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.

[0057] Below, lithium metal batteries according to exemplary implementation examples are described in more detail.

[0058] [Lithium metal battery]

[0059] According to one embodiment, a lithium metal battery is a lithium metal battery including a cathode layer; an anode current collector; and an electrolyte disposed between the cathode layer and the anode current collector, wherein the cathode layer includes a cathode current collector and a cathode active material layer disposed on one or both surfaces of the cathode current collector, and includes a lithium host layer disposed on one surface of the anode current collector, wherein the lithium host layer contains a lithium-affinity metal-organic framework including a lithium-affinity transition metal and an imidazole-based organic ligand and a binder, wherein the lithium-affinity transition metal is zinc (Zn), gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), nickel (Ni), manganese (Mn), cobalt (Co), or a combination thereof, and wherein the lithium-affinity metal-organic framework has a pore volume of 0.01 cm 3 / g or more, and the lithium host layer further includes pores, and the porosity of the lithium host layer is 40% to 70%.

[0060] The above lithium metal battery includes a negative electrode layer, and the negative electrode layer may contain the negative electrode current collector and a lithium host layer disposed on one surface of the negative electrode current collector.

[0061] The metal-organic framework structure according to one embodiment includes a microporous structure, a mesoporous structure, or a combination thereof.

[0062] The pore volume of the lithium-affinity metal-organic framework is the sum of the volumes of all pores present in the metal-organic framework, and is 0.01 to 1.0 cm 3 / g and was evaluated by the BET (Brunauer, Emmett, Teller) method. The pore volume of the lithium-affinity metal-organic framework is 0.02 to 0.09 cm 3 / g, 0.02 to 0.08 cm 3 / g, 0.025 to 0.08 cm 3 / g, 0.03 to 0.08 cm 3 / g, 0.03 to 0.07 cm 3 / g, 0.03 to 0.06 cm 3 / g or 0.035 to 0.06 cm 3 / g. The composite pore volume of the metal-organic framework is 0.01 cm 3 / g or less, the ability to store precipitated lithium is reduced, and the pore volume is less than 1.0 cm 3 If it exceeds / g, it may cause lithium side reactions and electrolyte depletion.

[0063] Since a lithium metal battery includes a lithium host layer in its anode layer, the non-uniformity of lithium deposition can be suppressed by the lithium host acting as a support during the deposition of lithium metal in the anode layer. This suppresses the formation and growth of lithium dendrites and / or isolated lithium (dead lithium) during the charge / discharge process of the lithium metal battery. Consequently, deterioration of the lithium metal battery is suppressed and cycle characteristics are improved.

[0064] By including a lithium host layer in the anode layer of a lithium metal battery, rapid volume changes in the anode layer during the charge / discharge process of the lithium metal battery can be suppressed. By suppressing rapid volume changes in the anode layer, deterioration of the lithium metal battery due to volume changes during the charge / discharge process of the lithium metal battery is suppressed, and cycle characteristics are improved.

[0065] The metal-organic framework is a porous structure, and the pores of the porous structure may include open pores, closed pores, or a combination thereof. The porous structure may include, for example, a microporous structure including micropores having a size of 2 nm or less, for example, 0.1 to 2 nm, a mesoporous structure including mesopores having a size of 2 nm to 50 nm, a macroporous structure including macropores having a size greater than 50 nm, or a combination thereof. The pores included in the macroporous structure may include, for example, pores having a size greater than 50 nm to 300 nm, or a combination thereof.

[0066] In one embodiment, the processed size of the metal-organic framework is 0.1 to 300 nm, 0.1 to 50 nm, 0.1 to 40 nm, 0.1 to 30 nm, 0.1 to 20 nm, 0.1 to 10 nm, 0.1 to 7 nm, or 0.1 to 5 nm. In another embodiment, the processed size of the metal-organic framework is 50 nm or less, for example, 5 to 50 nm, 5 to 40 nm, 5 to 30 nm, or 5 to 20 nm. Here, the pore size represents an average pore size, for example, an average pore diameter.

[0067] In another embodiment, the metal-organic framework may have composite pores containing micropores, mesopores, and macropores. The pore size of the metal-organic framework is, for example, pores having a size of 50 nm or less, 0.1 to 50 nm, 0.1 to 40 nm, 0.1 to 30 nm, 0.1 to 20 nm, 0.1 to 10 nm, or 0.2 to 1.5 nm.

[0068] If the pore size of the composite pores of the above metal-organic framework structure is less than 0.1 nm, the ability to store precipitated lithium is reduced, and if the pore size exceeds 300 nm, lithium side reactions and electrolyte depletion may occur.

[0069] The lithium-affinity metal-organic framework may be a carbon-based nanostructure based on the zeolitic-imidazolate framework (ZIF).

[0070] The imidazole-based organic ligand of the above metal-organic framework is a ligand made of an oxygen-free imidazole-based material, and has excellent high-voltage and high-temperature stability. Examples of the imidazole-based organic ligand include imidazole, 2-methylimidazole, 4-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, benzimidazole, methylbenzimidazole, 1-methyl-1H-imidazole, N-methylimidazole, or a combination thereof. In addition, the structure formation can be controlled by mixing the organic ligand as a metal-organic framework formation modulator. Examples of the metal-organic framework formation modulator include 1-methylimidazole, n-butylamine, cetyltrimethyl ammonium bromide (CTAB), or a combination thereof.

[0071] The metal-organic framework (MOF) structure may include, for example, Co-NC (Co embedded N-doped carbon, ZIF-67), Zn-NC (Zn embedded N-doped carbon, ZIF-8), or a combination thereof, and may include, for example, a ZIF (Zeolitic-imidazolate framework) structure.

[0072] Zn-NC (Zn embedded N-doped carbon, ZIF-8) is represented by the following chemical formula 33, the coordination metal is Zn, the linker is 2-methylimidazole, and the BET specific surface area is 1300 to 1800 m2 / g.

[0073] <Chemical Formula 33>

[0074]

[0075] The particle size of the metal-organic framework is 50 nm to 3 um, 100 nm to 3 um, 100 nm to 2 um, 200 nm to 1 um, or 200 nm to 600 nm. When the particle size of the metal-organic framework is within the above range, the ability to store precipitated lithium is excellent.

[0076] The porosity of the lithium host layer is 40% to 70%, 40% to 68%, 40% to 65%, 42% to 65%, 45% to 65%, 45% to 60%, or 45% to 55%. When the porosity of the lithium host layer is within the above range, the non-uniformity of lithium deposition can be suppressed by the lithium host acting as a support during the process of lithium metal deposition in the negative electrode layer. In the present disclosure, the porosity of the lithium host layer is expressed as a ratio of the volume occupied by pores to the total volume of the lithium host layer, and can be evaluated by the following Equation 1.

[0077] <Formula 1>

[0078] Porosity of lithium host layer = {(total volume of lithium host layer - total volume of lithium host layer components) / total volume of lithium host layer} x 100

[0079] In Equation 1, the total volume of the lithium host layer (cm 3 ) = Area of ​​lithium host layer (cm2) x Thickness of lithium host layer (cm),

[0080] The volume of the components of the lithium host layer can be expressed by the following equation 2.

[0081] <Formula 2>

[0082] Volume of components of the lithium host layer (cm) 3 ) = (Weight of components of lithium host layer (g) * Ratio of components of lithium host layer in lithium host layer) / Total density of components of lithium host layer (g / cm3)

[0083] The components of the lithium host layer refer to the components that constitute the lithium host layer, for example, a metal-organic framework, a conductive material, and a binder.

[0084] The area of ​​the lithium host layer varies depending on the battery design capacity, lithium host layer casting thickness, etc., and is, for example, 1 to 1,000 cm2, 1 to 900 cm2, 1 to 500 cm2, 1 to 300 cm2, 1 to 100 cm2, 1 to 50 cm2, 1 to 30 cm2, or 1 to 10 cm2.

[0085] Alternatively, the porosity of the lithium host layer can be measured using a mercury intrusion porosimeter or evaluated using a scanning electron microscope.

[0086] According to one embodiment, the thickness of the lithium host layer is 20 ㎛ to 300 ㎛, 30 ㎛ to 300 ㎛, 50 ㎛ to 200 ㎛, or 60 ㎛ to 150 ㎛. When the thickness of the lithium host layer is within the above range, the non-uniformity of lithium deposition can be suppressed by the lithium host acting as a support during the process of lithium metal deposition on the negative electrode layer. The formation and growth of lithium dendride and / or isolated lithium (dead lithium) can be suppressed during the charge / discharge process of the lithium metal battery. As a result, deterioration of the lithium metal battery is suppressed and cycle characteristics are improved.

[0087] In another embodiment, the thickness of the lithium host layer is 50 nm to 1 μm.

[0088] There is no lithium precipitation layer between the negative electrode current collector and the lithium host layer. When charging, the lithium precipitation layer is absent between the negative electrode current collector and the lithium host layer, so the lithium host layer remains bound to the current collector.

[0089] Furthermore, by arranging an inert material on one side of the cathode layer, short circuits between lithium dendrites generated and grown during charging and discharging of a lithium metal battery and the cathode and / or lithium metal melting at high temperatures are more effectively suppressed. Consequently, short circuits in the lithium metal battery are prevented and the life characteristics are improved.

[0090] Referring to FIG. 4, a lithium metal battery includes a cathode layer (10); a cathode layer (20); and an electrolyte layer (30) disposed between the cathode layer (10) and the cathode layer (20). The cathode layer (10) includes a cathode current collector (11) and a cathode active material layer (12) disposed on one or both surfaces of the cathode current collector (11).

[0091] Referring to FIG. 4, a second inert member (41) may be disposed on one side of the positive electrode active material layer (12) and may be disposed between the solid electrolyte layer (40) and the positive electrode current collector (11) facing the solid electrolyte layer (40). The second inert member (41) is not disposed on one side of the positive electrode current collector (11). The second inert member (41) may be omitted.

[0092] The negative electrode layer (20) includes a negative electrode current collector (21) and a lithium host layer (22) disposed on one surface of the negative electrode current collector (21). The lithium host layer (22) includes a metal-organic framework structure. The lithium metal battery may include a first inactive member (42) disposed on one surface of the negative electrode layer (20).

[0093] [Cathode layer]

[0094] [Cathode layer: lithium host]

[0095] Referring to FIG. 4, the negative electrode layer (20) includes a lithium host layer (22). The lithium host layer (22) includes a lithium-affinity metal-organic framework including a lithium-affinity transition metal and an imidazole-based organic ligand and a binder, wherein the lithium-affinity transition metal is zinc (Zn), gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), nickel (Ni), manganese (Mn), cobalt (Co), or a combination thereof, and the lithium host layer further includes pores, and the pore volume of the metal-organic framework is 0.01 to 1.0 cm. 3 / g, and the porosity of the lithium host layer is 40% to 70%. By using such a lithium host layer, lithium precipitation within the lithium host layer (22) can proceed more easily and uniformly.

[0096] A protective layer may be further disposed on top of the lithium host layer. By disposing the protective layer in this manner, the mechanical durability and electrochemical stability of the lithium host layer may be improved. Consequently, the cycle characteristics of a lithium metal battery including the lithium host layer may be improved. The protective layer may include, for example, a protective material. The protective material may include, for example, an organic material, an inorganic material, an organic-inorganic composite material, or a combination thereof. The organic material may be, for example, a polymer. The inorganic material may be, for example, a metal oxide.

[0097] [Cathode layer: binder]

[0098] The binder included in the lithium host layer (22) may include a crosslinked polymer of the first polymer and the second polymer, which are crosslinking reaction products of the first polymer containing a hydroxyl group and the second polymer having a crosslinkable functional group.

[0099] The weight ratio of the first polymer and the second polymer is 50:50 to 99:1, and the second polymer is at least one selected from among fluorinated polyamic acid and fluorinated polyimide having a carboxyl group.

[0100] The above hydroxyl group-containing first polymer is carboxymethyl cellulose (CMC); polyvinyl alcohol (PVA); Vinyl acetate, butyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 2-hydroxyethylene glycol (meth)acrylate, 2-hydroxypropylene glycol (meth)acrylate, acrylic acid, methacrylic acid, 2-(meth)acryloyloxy acetic acid, 3-(meth)acryloyloxy propyl acid, 4-(meth)acryloyloxy butyric acid, itaconic acid, maleic acid, 2-isocyanatoethyl (meth)acrylate, 3-isocyanatopropyl (meth)acrylate, A polymerization reaction product of one or more monomers selected from among 4-isocyanatobutyl (meth)acrylate, (meth)acrylamide, ethylene di(meth)acrylate, diethylene glycol (meth)acrylate, triethylene glycol di(meth)acrylate, trimethylene propane tri(meth)acrylate, trimethylene propane triacrylate, 1,3-butanediol (meth)acrylate, 1,6-hexanediol di(meth)acrylate, allyl acrylate, and N-vinyl caprolactam, or a hydrolyzate thereof, may be mentioned.

[0101] The first polymer may be polyvinyl alcohol (PVA). For example, polyvinyl alcohol may be a hydrolyzate obtained by hydrolyzing polyvinyl acetate with an alkali.

[0102] The degree of saponification of the polyvinyl alcohol may be 60 to 99%, 70 to 95%, 75 to 90%, or 80 to 90%. For example, the degree of saponification of the polyvinyl alcohol may be 85 to 90%. In the above saponification range, the physical properties due to the lithium host layer may be further improved.

[0103] The weight average molecular weight of the first polymer may be 10,000 to 500,000 Dalton, 10,000 to 500,000 Dalton, 10,000 to 400,000 Dalton, 10,000 to 300,000 Dalton, 10,000 to 200,000 Dalton, 50,000 to 150,000 Dalton, 70,000 to 100,000 Dalton, or 80,000 to 100,000 Dalton. The physical properties of the protective film may be further improved within the weight average molecular weight range of the first polymer. In the present disclosure, the weight average molecular weight of the first polymer can be measured by gel permeation chromatography.

[0104] The lithium host layer may further include a second polymer having a functional group capable of crosslinking with the first polymer containing a hydroxyl group. In this case, the lithium host layer further includes a crosslinked polymer of the first polymer and the second polymer.

[0105] The second polymer comprises at least one selected from among fluorinated polyamic acid and fluorinated polyimide having a carboxyl group.

[0106] The above polyamic acid is represented by the following chemical formula 9 or 10, and the above polyimide is a polymer represented by the following chemical formula 11 or 12.

[0107] [Chemical Formula 9]

[0108]

[0109] [Chemical Formula 10]

[0110]

[0111] [Chemical Formula 11]

[0112]

[0113] [Chemical Formula 12]

[0114]

[0115] In the above equations, n and m are the mole fractions within the repeating unit, respectively, and 0 <n≤1, 0≤m<1, n+m=1이다.

[0116] For example, in the second polymer, the mole fractions of repeating units containing a crosslinking group and repeating units not containing a crosslinking group are each 0. <n≤0.5, 0.5≤m<1 및 n+m=1일 수 있다. 예를 들어, 상기 제2 고분자에서 가교기를 포함하는 반복단위와 가교기를 포함하지 않는 반복단위의 몰분율이 각각 0.1≤n≤0.4, 0.6≤m≤0.9 및 n+m=1일 수 있다. 예를 들어, 상기 제2 고분자에서 가교기를 포함하는 반복단위와 가교기를 포함하지 않는 반복단위의 몰분율이 각각 0.15≤n≤0.35, 0.65≤m≤0.85 및 n+m=1일 수 있다. 예를 들어, 상기 제2 고분자에서 가교기를 포함하는 반복단위와 가교기를 포함하지 않는 반복단위의 몰분율이 각각 0.2≤n≤0.3, 0.7≤m≤0.8 및 n+m=1일 수 있다. 상기 몰분율 범위에서 더욱 향상된 물성을 제공할 수 있다.

[0117] For example, the second polymer may be a random copolymer. For example, the second polymer may be a block copolymer.

[0118] The weight average molecular weight of the second polymer may be 10,000 to 1,200,000 Dalton, 10,000 to 1,100,000 Dalton, 10,000 to 1,000,000 Dalton, 10,000 to 500,000 Dalton, 100,000 to 500,000 Dalton, 100,000 to 400,000 Dalton, for example, 100,000 to 300,000 Dalton. The properties of the protective film may be further improved within the weight average molecular weight range of the first polymer.

[0119] In the above protective film, the weight ratio of the first polymer and the second polymer containing a hydroxyl group included in the third polymer may be 99:1 to 50:50, 95:5 to 55:45, 95:5 to 60:40, 95:5 to 65:35, or 90:10 to 70:30. The physical properties of the protective film may be further improved within the weight ratio range of the first polymer to the second polymer.

[0120] The hydroxyl groups of the first polymer and the carboxyl groups of the second polymer react with each other to form an ester bond, thereby forming a third polymer crosslinked with the first and second polymers. The formation of the third polymer enhances the stability of the protective film, and in the case of halogen groups such as fluorine functional groups, it can improve interfacial stability by reducing the formation of irreversible lithium inclusions.

[0121] The protective film according to an embodiment includes a crosslinked polymer of polyvinyl alcohol and polyamic acid as a crosslinked polymer. The polyamic acid is, for example, a polymer represented by the chemical formula 9 or 10 described above.

[0122] In another embodiment, the crosslinked polymer of the protective film is a crosslinked polymer of polyvinyl alcohol and fluorinated polyimide (PVA / PI-f). The fluorinated polyimide is a polymer represented by the chemical formula 11 or 12 described above.

[0123] The weight average molecular weight of the crosslinked polymer is 100,000 to 1,000,000 Dalton, 100,000 to 500,000 Dalton, 100,000 Dalton to 300,000 Dalton or 200,000 Dalton.

[0124] The above binder is not necessarily limited to, but may include, for example, styrene-butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, vinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, polymethyl methacrylate, etc., and any binder used in the art may be used. The binder may be composed of a single binder or a plurality of different binders.

[0125] A binder can bind multiple lithium hosts to each other to form a lithium host structure. If the lithium host layer (20) does not include a binder, the lithium host structure included in the lithium host layer (20) may have difficulty maintaining mechanical stability. That is, during the charge / discharge process of a lithium metal battery, the lithium host structure may collapse, forming a lithium metal layer, from which lithium dendrites may grow toward the positive electrode, resulting in a short circuit.

[0126] [Cathode layer: interlayer]

[0127] The lithium metal battery may further include, for example, an interlayer (not shown) disposed between the lithium host layer (22) and the solid electrolyte layer (30).

[0128] By arranging an interlayer between the lithium host layer (22) and the solid electrolyte layer (30), the bonding force between the lithium host layer (22) and the solid electrolyte can be increased. Accordingly, the structural stability of the lithium host layer (22) can be improved during the charge / discharge process of the lithium metal battery. In addition, the side reaction between the lithium metal precipitated on the lithium host layer (22) and the solid electrolyte layer (30) during the charge / discharge process of the lithium metal battery can be suppressed. Accordingly, the cycle characteristics of the lithium metal battery including the interlayer can be further improved.

[0129] The intermediate layer may include a binder. The binder included in the intermediate layer may be, but is not limited to, styrene-butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, vinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, polymethyl methacrylate, etc., and any binder used in the art may be used. The binder may be composed of a single binder or a plurality of different binders. The binder may be, for example, a fluorinated binder. The fluorinated binder may be, for example, polyvinylidene fluoride.

[0130] [Cathode layer: Other additives]

[0131] The lithium host layer (22) may further include additives used in conventional lithium metal batteries, such as fillers, coating agents, dispersants, and ion conductivity aids.

[0132] [Cathode layer: lithium host layer]

[0133] The ratio (B / A) of the initial charge capacity (B) of the lithium host layer (22) and the initial charge capacity (A) of the positive electrode active material layer is, for example, 0 to 0.45. The initial charge capacity of the positive electrode active material layer (12) is determined by the first open circuit voltage (1 stLi / Li from open circuit voltage) + The initial charge capacity of the lithium host layer (22) is determined at the maximum charging voltage. The initial charge capacity of the lithium host 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.

[0134] The maximum charging voltage is determined by the type of 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 the cathode active material is Li / Li. +It can be 2.5 V, or 3.0 V. The ratio (B / A) of the initial charge capacity (B) of the lithium host layer (22) and the initial charge capacity (A) of the positive electrode active material layer is, for example, more than 0 to 0.3, 0.01 to 0.2, or 0.05 to 0.1. The initial charge capacity of the lithium host layer (22) is the charge capacity that the lithium host itself has in the lithium host layer (22). That is, the initial charge capacity of the lithium host layer (22) is the charge capacity before lithium metal is precipitated from the lithium host layer (22). In the lithium host layer (22) including the electrochemically inactive lithium host, the initial charge capacity of the lithium host layer (22) is, for example, 0. For example, in the lithium host layer including the electrochemically inactive carbon paper, the initial charge capacity is 0. In a lithium host layer including an electrochemically active lithium host, the initial charge capacity is, for example, greater than 0 to 0.3, 0.01 to 0.2, or 0.05 to 0.1. For example, in a lithium host layer including an electrochemically active porous graphite foam, the initial charge capacity is, for example, greater than 0 to 0.45. If the ratio (B / A) of the initial charge capacity (B) of the lithium host layer (22) to the initial charge capacity (A) of the positive electrode active material layer exceeds 0.45, the ratio of lithium absorbed into the lithium host itself becomes excessively high compared to lithium precipitated within the lithium host layer (22), so that the energy density of the lithium metal battery may be reduced.

[0135] 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 positive electrode active material by the mass (g) of the positive electrode active material in the positive electrode active material layer (12). When multiple types of positive electrode active materials are used, the charge capacity density × mass value is calculated for each 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 lithium host layer (22) is also calculated in the same way. The initial charge capacity of the lithium host layer (22) is obtained by multiplying the charge capacity density (mAh / g) of the lithium host by the mass of the lithium host in the lithium host layer (22). When multiple types of lithium hosts are used, the charge capacity density χ mass value is calculated for each lithium host, and the sum of these values ​​is the initial charge capacity of the lithium host layer (22). The charge capacity density of each of the positive electrode active material and the lithium host 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 lithium host layer (22) is constant at a current density, for example, 0.1 mA / cm 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, e.g., 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. 2It 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 It can be. 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 satisfying the safety conditions according to JISC8712:2015 of the Japanese Standards Association. If the initial charge capacity of the lithium host layer (22) is 0, the lithium host acts only as a support for accommodating the precipitated lithium. If the initial charge capacity of the lithium host layer is greater than 0, the lithium host simultaneously functions as a negative electrode active material and a support for accommodating the precipitated lithium.

[0136] The thickness of the lithium host layer (22) may be, for example, 10% or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, or 90% or more of the thickness of the positive electrode active material layer. The thickness of the lithium host layer may be, for example, 100% or less, 99% or less, 98% or less, or 97% or less of the thickness of the positive electrode active material layer. The thickness of the lithium host layer may be, for example, 10% to 100%, 30% to 100%, 40% to 100%, 50% to 100%, 60% to 99%, 70% to 98%, or 80% to 97% of the thickness of the positive electrode active material layer. When the lithium host layer has a thickness in this range, the cycle characteristics of the lithium metal battery can be further improved. The thickness of the lithium host layer (22) may be, for example, 10% or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, or 90% or more of the thickness of the solid electrolyte layer. The thickness of the lithium host layer may be, for example, 100% or less, 99% or less, 98% or less, or 97% or less of the thickness of the solid electrolyte layer. The thickness of the lithium host layer may be, for example, 10% to 100%, 30% to 100%, 40% to 100%, 50% to 100%, 60% to 99%, 70% to 98%, or 80% to 97% of the thickness of the solid electrolyte layer. When the lithium host layer has a thickness in this range, the cycle characteristics of the lithium metal battery can be further improved. The thickness of the lithium host layer (22) is, for example, 20 µm to 300 µm, 30 µm to 300 µm, 50 µm to 200 µm, or 100 µm to 200 µm. If the thickness of the lithium host layer (22) is too thin, the content of lithium metal accommodated in the lithium host layer (22) may be excessively reduced, resulting in excessive reduction in the capacity of the lithium metal battery. If the thickness of the lithium host layer (22) is excessively increased, the energy density of the lithium metal battery may be reduced.

[0137] The lithium host layer may include pores.

[0138] The assembled lithium metal battery or a partially or fully discharged lithium metal battery may include pores, for example, within the lithium host layer (22). The volume contained in the pores in the lithium host layer may be 1 to 99 vol%, 5 to 95 vol%, 10 to 90 vol%, 20 to 80 vol%, or 30 to 70 vol% of the total volume of the lithium host layer. The volume of the lithium host layer may be calculated from the product of the thickness and area of ​​the lithium host layer.

[0139] The lithium host layer may have lithium metal or a lithium alloy disposed in some or all of the pores after the lithium metal battery is charged. By accommodating the lithium metal or lithium alloy in the pores included in the lithium host layer, volume changes in the lithium host layer can be suppressed during the charge / discharge process of the lithium metal battery. Accordingly, by suppressing volume changes in the negative electrode layer, such as changes in the thickness of the negative electrode layer, during the charge / discharge process of the lithium metal battery, the structural stability of the lithium metal battery is improved, and as a result, deterioration of the lithium metal battery can be suppressed more effectively.

[0140] [Cathode layer: negative electrode collector]

[0141] 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.

[0142] The lithium metal battery may further include, for example, a thin film including an element capable of forming an alloy with lithium on one surface of the negative electrode current collector (21), although not shown in the drawing. The thin film is disposed between the negative electrode current collector (21) and the lithium host layer (22). The thin film includes, 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 may be composed of one of these metals or an alloy of several types of metals. By disposing the thin film on one surface of the negative electrode current collector (21), for example, the deposition shape of the second negative electrode active material layer deposited between the thin film and the lithium host layer (22) becomes flatter, and the cycle characteristics of the lithium metal battery can be further improved.

[0143] The thickness of the thin film 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 is less than 1 nm, it may be difficult for the function of the thin film to be exerted. If the thickness of the thin film is too thick, the thin film itself may absorb lithium, which may reduce 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 metal battery. The thin film 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 a thin film in the relevant technical field may be used.

[0144] 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 include, for example, polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polybutylene terephthalate (PBT), polyimide (PI), or a combination thereof. The metal layer may include, for example, copper (Cu), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), or an alloy thereof. Since the negative electrode current collector (21) has such a structure, the weight of the electrode can be reduced, and consequently, the energy density of the all-solid-state secondary battery can be improved.

[0145] [Cathode layer: first inert member]

[0146] Referring to Fig. 4, the negative electrode layer (20) includes a negative electrode current collector (21) and a lithium host layer (22) disposed on one side of the negative electrode current collector (21). A first inactive member (42) is disposed on one side of the negative electrode layer (20).

[0147] The first inactive member (42) is disposed on one side of the lithium host layer (22) and is disposed between the solid electrolyte layer (40) and the negative electrode current collector (21) facing the solid electrolyte layer (40). The first inactive member (42) is not disposed on one side of the negative electrode current collector (21).

[0148] Referring to FIG. 5, the first inert member (42) is disposed on one side of the lithium host layer (22) and the negative electrode current collector (21). By including the first inert member (42), a short circuit between the lithium metal deposited on the lithium host layer (22) and the positive electrode layer (10) during charge and discharge of the lithium metal battery is more effectively prevented, resulting in improved cycle characteristics of the lithium metal battery. By including the first inert member (42), cracking of the solid electrolyte layer (30) is prevented during manufacture and / or charge and discharge of the lithium metal battery, resulting in improved cycle characteristics of the lithium metal battery. In a lithium metal battery that does not include the first inert member (42), cracks may occur in the solid electrolyte layer (30) when in contact with the negative electrode layer (20) during manufacture and / or charge and discharge of the lithium metal battery, which increases the possibility of a short circuit occurring due to the growth of lithium metal therethrough.

[0149] Referring to FIGS. 4 and 5, in the lithium metal battery, the thickness (T2) of the first inactive member (42) is substantially the same as the thickness (T1) of the lithium host layer (22). Since the sum of the thickness (T2) of the first inactive member (42) and the thickness (T4) of the negative electrode current collector (21) is substantially the same as the thickness (T3) of the negative electrode layer (20), a uniform pressure is applied between the negative electrode layer (20) and the solid electrolyte layer (30), and the negative electrode layer (20) and the solid electrolyte layer (30) are sufficiently adhered to each other, thereby reducing the interfacial resistance between the negative electrode layer (20) and the solid electrolyte layer (30). In addition, since the solid electrolyte layer (30) is sufficiently sintered during the pressurized manufacturing process of the lithium metal battery, the internal resistance of the solid electrolyte layer (30) and the lithium metal battery including the same is reduced.

[0150] Referring to FIGS. 4 and 5, in the lithium metal battery, the thickness of the first inert member (42) is greater than the thickness of the lithium host layer (22). In the lithium metal battery, the thickness of the first inert member (42) is substantially the same as the thickness of the negative electrode layer (20). Since the thickness (T2) of the first inert member (42) is substantially the same as the thickness of the negative electrode layer (20), a uniform pressure is applied between the negative electrode layer (20) and the solid electrolyte layer (30), and the negative electrode layer (20) and the solid electrolyte layer (30) are sufficiently adhered to each other, thereby reducing the interfacial resistance between the negative electrode layer (20) and the solid electrolyte layer (30). In addition, since the solid electrolyte layer (30) is sufficiently sintered during the pressurized manufacturing process of the lithium metal battery, the internal resistance of the solid electrolyte layer (30) and the lithium metal battery including the same is reduced.

[0151] Referring to FIGS. 4 and 5, the first inert member (42) surrounds the side surface of the cathode layer (20) and is in contact with the solid electrolyte layer (30). Since the first inert member (42) surrounds the side surface of the cathode layer (20) and is in contact with the solid electrolyte layer (30), cracks in the solid electrolyte layer (30) that occur due to a pressure difference during the pressing process in the solid electrolyte layer (30) that is not in contact with the anode layer (20) can be effectively suppressed. The first inert member (42) surrounds the side surface of the cathode layer (20) and is separated from the anode layer (10). The first inert member (42) surrounds the side surface of the cathode layer (20), is in contact with the solid electrolyte layer (30), and is separated from the anode layer (10). Accordingly, the possibility of a short circuit occurring due to physical contact between the positive electrode layer (10) and the lithium host layer (22) or due to overcharging of lithium, etc., is suppressed. Referring to FIGS. 4 and 5, the possibility of a short circuit occurring due to contact between the negative electrode collector (21) and the positive electrode layer (10) is more effectively suppressed by simultaneously disposing the first inactive member (42) on one side of the lithium host layer (22) and the negative electrode collector (21).

[0152] Referring to FIGS. 4 and 5, the first inert member (42) extends from one side of the lithium host layer (22) or the negative electrode layer (20) to the end of the solid electrolyte layer (30). Since the first inert member (42) extends to the end of the solid electrolyte layer (30), cracks occurring at the end of the solid electrolyte layer (30) can be suppressed. The end of the solid electrolyte layer (30) is the outermost part that is in contact with the side of the solid electrolyte layer (30). The first inert member (42) extends to the outermost part that is in contact with the side of the solid electrolyte layer (30). The first inert member (42) is separated from the positive electrode layer (10). The first inert member (42) extends to the end of the solid electrolyte layer (30), but does not contact the positive electrode layer (10). The first inert member (42) fills a space extending from one side of the lithium host layer (22) or the negative electrode layer (20) to the end of the solid electrolyte layer (30), for example.

[0153] The first inert member (42) may be a gasket. By using a gasket as the first inert member (42), cracks in the solid electrolyte layer (30) caused by a pressure difference during the pressing process can be effectively suppressed.

[0154] The first inert member (42) has, for example, a single-layer structure. Alternatively, although not shown in the drawing, the first inert member (42) may have a multi-layer structure. In the first inert member (42) having a multi-layer structure, each layer may have a different composition. The first inert member (42) 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.

[0155] [Anode layer]

[0156] [Anode layer: cathode active material]

[0157] Referring to FIGS. 4 and 5, the positive electrode active material layer (12) includes a positive electrode active material.

[0158] A compound capable of reversible intercalation and deintercalation of lithium (a lithiated intercalation compound) can be used as a cathode active material. Specifically, one or more of a composite oxide of lithium and a metal selected from cobalt, manganese, nickel, and combinations thereof can be used.

[0159] The above composite oxide may be a lithium transition metal composite oxide, and specific examples thereof include lithium nickel-based oxide, lithium cobalt-based oxide, lithium manganese-based oxide, lithium iron phosphate-based compound, cobalt-free nickel-manganese-based oxide, or a combination thereof.

[0160] As an example, a compound represented by any one of the following chemical formulas may be used: Li a A 1-b X b O 2-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Mn 2-b X b O 4-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Ni 1-b-c Co b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni 1-b-c Mn b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni b Co c L 1 d G e O2(0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0≤e≤0.1); Li a NiG bO2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a CoG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-b G b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn2G b O4(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-g G g PO4(0.90≤a≤1.8, 0≤g≤0.5); Li (3-f) Fe2(PO4)3(0≤f≤2); Li a FePO4(0.90≤a≤1.8).

[0161] In the above chemical formula, A is Ni, Co, Mn, or a combination thereof; X is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof; D is O, F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; L 1 is Mn, Al or a combination thereof.

[0162] The cathode active material may include, for example, a lithium transition metal oxide represented by the following chemical formulas 25 to 32:

[0163] <Chemical Formula 25>

[0164] Li a Ni x Co y M z O 2-b A b

[0165] In the above chemical formula 25, 1.0≤a≤1.2, 0≤b≤0.2, 0.8≤x<1, 0≤y≤0.3, 0 <z≤0.3, 및 x+y+z=1이고,

[0166] M is manganese (Mn), niobium (Nb), vanadium (V), magnesium (Mg), gallium (Ga), silicon (Si), tungsten (W), molybdenum (Mo), iron (Fe), chromium (Cr), copper (Cu), zinc (Zn), titanium (Ti), aluminum (Al), boron (B), or a combination thereof,

[0167] A is F, S, Cl, Br or a combination thereof,

[0168] <Chemical Formula 26>

[0169] LiNi x Co y Mn z O2

[0170] <Chemical Formula 27>

[0171] LiNi x Co y Al z O2

[0172] In the above chemical formulas 26 and 27, 0.8≤x≤0.95, 0≤y≤0.2, 0 <z≤0.2 및 x+y+z=1이며,

[0173] <Chemical Formula 28>

[0174] LiNi x Co y Mn z Al w O2

[0175] In the above chemical formula 28, 0.8≤x≤0.95, 0≤y≤0.2, 0 <z≤0.2, 0<w≤0.2, 및 x+y+z+w=1이며,

[0176] <Chemical Formula 29>

[0177] Li a Co x M y O 2-b A b

[0178] In the above chemical formula 29, 1.0≤a≤1.2, 0≤b≤0.2, 0.9≤x≤1, 0≤y≤0.1, and x+y=1,

[0179] M is manganese (Mn), niobium (Nb), vanadium (V), magnesium (Mg), gallium (Ga), silicon (Si), tungsten (W), molybdenum (Mo), iron (Fe), chromium (Cr), copper (Cu), zinc (Zn), titanium (Ti), aluminum (Al), boron (B) or a combination thereof, and A is F, S, Cl, Br or a combination thereof.

[0180] <Chemical Formula 30>

[0181] Li a Ni x Mn y M' z O 2-b A b

[0182] In the above chemical formula 30, 1.0≤a≤1.2, 0≤b≤0.2, 0 <x≤0.3, 0.5≤y<1, 0<z≤0.3, 및 x+y+z=1이고, M'는 코발트(Co), 니오븀(Nb), 바나듐(V), 마그네슘(Mg), 갈륨(Ga), 실리콘(Si), 텅스텐(W), 몰리브덴(Mo), 철(Fe), 크롬(Cr), 구리(Cu), 아연(Zn), 티타늄(Ti), 알루미늄(Al), 보론(B) 또는 이들의 조합이고, A는 F, S, Cl, Br 또는 이들의 조합이며,

[0183] <Chemical Formula 31>

[0184] Li a M1 x M2 y PO 4-b X b

[0185] In the above chemical formula 31, 0.90≤a≤1.1, 0≤x≤0.9, 0≤y≤0.5, 0.9 <x+y<1.1, 0≤b≤2 이며,

[0186] M1 is chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zirconium (Zr) or a combination thereof,

[0187] M2 is magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), titanium (Ti), zinc (Zn), boron (B), niobium (Nb), gallium (Ga), indium (In), molybdenum (Mo), tungsten (W), aluminum (Al), silicon (Si), chromium (Cr), vanadium (V), scandium (Sc), yttrium (Y) or a combination thereof, and X is O, F, S, P or a combination thereof.

[0188] <Chemical Formula 32>

[0189] Li a M3 z PO4

[0190] In the above chemical formula 32, 0.90≤a≤1.1, 0.9≤z≤1.1, and M3 is chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zirconium (Zr), or a combination thereof.

[0191] The cathode active material layer may further include a conductive material. Examples of conductive materials include, but are not limited to, carbon black, graphite particles, natural graphite, artificial graphite, acetylene black, Ketjen black, carbon fibers, carbon nanotubes, metal powders or metal fibers or metal tubes such as copper, nickel, aluminum, and silver, and conductive polymers such as polyphenylene derivatives. Any conductive material used in the art may be used. Alternatively, the cathode may not include a separate conductive material, for example.

[0192] The cathode active material layer may further include, for example, a binder. Examples of binders that may be used include vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride, polyacrylonitrile, polymethyl methacrylate, polytetrafluoroethylene (PTFE), a mixture of the aforementioned polymers, and a styrene butadiene rubber-based polymer.

[0193] The content of the positive electrode active material included in the positive electrode active material layer may be 80 wt% to 99 wt%, 90 wt% to 99 wt%, or 95 wt% to 99 wt% of the total weight of the positive electrode active material layer (12).

[0194] The conductive material content included in the positive electrode active material layer may be 0.1 wt% to 10 wt% or 0.1 wt% to 5 wt% of the total weight of the positive electrode active material layer (12).

[0195] The binder content included in the positive electrode active material layer may be 0.1 wt% to 10 wt% or 0.1 wt% to 5 wt% of the total weight of the positive electrode active material layer (12).

[0196] The contents of the cathode active material, conductive agent, and binder contained in the cathode are at levels typically used in lithium batteries. Depending on the intended use and configuration of the lithium battery, one or more of the conductive agent and binder may be omitted.

[0197] For example, the cathode active material may be a high-nickel cathode active material in which the nickel content is 80 mol% or more, 85 mol% or more, 90 mol% or more, 91 mol% or more, or 94 mol% or more and 99 mol% or less, based on 100 mol% of metals excluding lithium in the lithium transition metal composite oxide. The high-nickel cathode active material can realize high capacity and thus can be applied to high-capacity, high-density lithium secondary batteries.

[0198] [Anode: Anode current collector]

[0199] The material constituting the positive electrode collector may be any material that does not react with lithium, i.e., does not form an alloy or compound with lithium, and has conductivity. The positive electrode collector is, for example, a metal or an alloy. The positive electrode collector (11) may be made of, for example, aluminum (Al), indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), germanium (Ge), or an alloy thereof. The positive electrode collector may have a form selected from, for example, a sheet, a foil, a film, a plate, a porous body, a mesoporous body, a body containing through-holes, a polygonal ring body, a mesh body, a foam body, and a non-woven body, but is not necessarily limited to these forms, and any form used in the relevant technical field may be used.

[0200] Alternatively, the positive electrode current collector 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, the base film may soften or liquefy when a short circuit occurs, thereby blocking battery operation and suppressing a sudden increase in current. The metal layer may include, for example, aluminum (Al), indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), germanium (Ge), or an alloy thereof. The positive electrode current collector 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 positive electrode current collector (11), refer to the positive electrode current collector (11) described above. By having this structure, the positive electrode current collector (11) can reduce the weight of the positive electrode, and consequently, improve the energy density of the positive electrode and lithium battery.

[0201] A positive electrode for a lithium secondary battery may include a current collector and a positive electrode active material layer formed on the current collector. The positive electrode active material layer includes a positive electrode active material and may further include a binder and / or a conductive material.

[0202] For example, the anode may further include an additive that can act as a sacrificial anode.

[0203] The content of the positive electrode active material may be 90 wt% to 99.5 wt% with respect to 100 wt% of the positive electrode active material layer, and the contents of the binder and conductive material may be 0.5 wt% to 5 wt%, respectively, with respect to 100 wt% of the positive electrode active material layer.

[0204] The above binder serves to adhere the positive electrode active material particles well to each other and also to adhere the positive electrode active material well to the current collector. Representative examples of the binder include, but are not limited to, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers containing ethylene oxide, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, epoxy resin, (meth)acrylic resin, polyester resin, nylon, etc.

[0205] The conductive material is used to provide conductivity to the electrode, and any material that does not cause chemical changes and is electronically conductive can be used in the battery. Examples of the conductive material include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, and carbon nanotube; metal-based materials containing copper, nickel, aluminum, silver, etc. in the form of metal powder or metal fiber; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0206] Al may be used as the above current collector, but is not limited thereto.

[0207] [Anode: Second inert member]

[0208] Referring to FIG. 4, a second inert member (41) may be disposed on one side of the positive electrode active material layer (12) and may be disposed between the solid electrolyte layer (40) and the positive electrode current collector (11) facing the solid electrolyte layer (40). The second inert member (41) is not disposed on one side of the positive electrode current collector (11). The second inert member (41) may be omitted.

[0209] Referring to Fig. 5, the second inert member (41) is disposed on one side of the positive electrode active material layer (12) and the positive electrode current collector (11). By including the second inert member (41), cracking of the solid electrolyte layer (30) can be prevented during manufacturing of the lithium metal battery and / or charging / discharging, thereby improving the cycle characteristics of the lithium metal battery. The second inert member may be omitted.

[0210] [cathode]

[0211] A lithium secondary battery according to an embodiment includes a negative electrode, and the negative electrode includes a negative electrode collector.

[0212] [Cathode: Negative current collector]

[0213] The negative current collector includes, for example, a metal substrate. The metal substrate includes a first metal as a main component or is made of the first metal. The metal substrate includes a first metal as a main component or is made of the first metal. The content of the first metal included in the metal substrate is, for example, 90 wt% or more, 95 wt% or more, 99 wt% or more, or 99.9 wt% or more based on the total weight of the metal substrate. The metal substrate may be made of, for example, a material that does not react with lithium, i.e., does not form an alloy and / or compound with lithium. The first metal is, for example, copper (Cu), nickel (Ni), stainless steel (SUS), iron (Fe), and cobalt (Co), but is not necessarily limited thereto, and any metal used as a current collector in the art may be used. The first metal substrate may be made of, for example, one of the above-described metals, or may be made of an alloy of two or more metals. The metal substrate is, for example, in the form of a sheet or foil. The thickness of the negative electrode current collector may be, for example, 5 µm to 50 µm, 10 µm to 50 µm, 10 µm to 40 µm, or 10 µm to 30 µm, but is not necessarily limited to this range and may be selected depending on the characteristics of the required lithium metal battery.

[0214] The negative electrode current collector may further include a coating layer (not shown) comprising a second metal on a metal substrate. The negative electrode current collector may include, for example, a metal substrate; and a coating layer disposed on the metal substrate and comprising a second metal. The second metal has a higher Mohs hardness than the first metal. That is, since the coating layer comprising the second metal is harder than the metal substrate comprising the first metal, deterioration of the first metal substrate can be prevented. The Mohs hardness of the material constituting the metal substrate is, for example, 5.5 or less. The Mohs hardness of the first metal is, for example, 5.5 or less, 5.0 or less, 4.5 or less, 4.0 or less, 3.5 or less, or 3.0 or less. The Mohs hardness of the first metal may be, for example, 2.0 to 6.0. The Mohs hardness of the material constituting the coating layer is, for example, 6.0 or more. For example, the Mohs hardness of the second metal is 6.0 or more, 6.5 or more, 7.0 or more, 7.5 or more, 8.0 or more, 8.5 or more, or 9.0 or more. The Mohs hardness of the second metal may be, for example, 6.0 to 12. If the Mohs hardness of the second metal is too low, it may be difficult to suppress deterioration of the negative electrode current collector. If the Mohs hardness of the second metal is too high, processing may not be easy. The second metal is, for example, one or more selected from titanium (Ti), manganese (Mn), niobium (Nb), tantalum (Ta), iridium (Ir), vanadium (V), rhenium (Re), osmium (Os), tungsten (W), chromium (Cr), boron (B), ruthenium (Ru), and rhodium (Rh). The thickness of the coating layer can be, for example, 10 nm to 1 μm, 50 nm to 500 nm, 50 nm to 200 nm, or 50 nm to 150 nm.

[0215] Alternatively, the negative electrode current collector 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, the base film may soften or liquefy when a short circuit occurs, thereby blocking battery operation and suppressing a sudden increase in current. The metal layer may include, for example, copper (Cu), nickel (Ni), stainless steel (SUS), iron (Fe), and cobalt (Co), or an alloy thereof. The metal layer may act as an electrochemical fuse, which may be cut off in the event of an overcurrent to prevent a short circuit. 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 negative electrode current collector (21) decreases, thereby improving the stability of the lithium battery in the event 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 melts, so that the metal layer can be electrically connected to the lead tab. In order to strengthen the welding of the metal layer and the lead tab, a metal chip can be added between the metal layer and the lead tab. The metal chip can 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, an aluminum foil, a copper foil, a 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 by welding the lead tab. 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 ㎛, 1.5 to 50 ㎛, 1.5 to 40 ㎛, 1 to 30 ㎛, 1 to 20 ㎛, or 1 to 10 ㎛. 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 negative electrode current collector (21) can reduce the weight of the negative electrode and consequently improve the energy density of the negative electrode and lithium battery.

[0216] [Electrolyte layer]

[0217] The electrolyte may be, for example, a liquid electrolyte, a solid electrolyte, a gel electrolyte, or a combination thereof. The electrolyte is, for example, an organic electrolyte. The liquid electrolyte is as mentioned in the liquid electrolyte of the gel polymer electrolyte.

[0218] The solid electrolyte is, for example, an oxide-based solid electrolyte, a sulfide-based solid electrolyte, a polymer solid electrolyte, or a combination thereof.

[0219] 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.

[0220] A gel electrolyte is, for example, a polymer gel electrolyte. A gel electrolyte can have a gel state without containing a polymer, for example.

[0221] 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 may include, for example, one or more cations selected from among a) ammonium compounds, pyrrolidinium compounds, pyridinium compounds, pyrimidinium compounds, imidazolium compounds, piperidinium compounds, pyrazolium compounds, oxazolium compounds, pyridazinium compounds, phosphonium compounds, sulfonium compounds, triazolium compounds, and mixtures thereof, and b) one or more anions selected from among BF4-, PF6-, AsF6-, SbF6-, AlCl4-, HSO4-, ClO4-, CH3SO3-, CF3CO2-, Cl-, Br-, I-, SO4-, CF3SO3-, (FSO2)2N-, (C2F5SO2)2N-, (C2F5SO2)(CF3SO2)N-, and (CF3SO2)2N-. A polymer solid electrolyte can form a polymer gel electrolyte, for example, by being impregnated into a liquid electrolyte 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.

[0222] In a lithium metal battery according to an embodiment, the liquid electrolyte contains a lithium salt and an organic solvent.

[0223] As the organic solvent, for example, an aprotic organic solvent such as N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, gamma-butyrolactone, 1,2-dimethoxyethane, tetrahydroxy franc, 2-methyl tetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolan, formamide, dimethylformamide, dioxolane, acetonitrile, nitromethane, methyl formate, methyl acetate, triester phosphate, trimethoxy methane, dioxolane derivatives, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate derivatives, tetrahydrofuran derivatives, ethers, methyl pyropionate, ethyl propionate, etc. can be used. Carbonate solvents such as propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, and diethyl carbonate can be used.

[0224] The above lithium salt can be any one commonly used in lithium secondary batteries, and is a substance that is easily dissolved in a non-aqueous solvent, for example, one or more of the following substances can be used: LiSCN, LiN(CN)2, LiClO4, LiBF4, LiAsF6, LiPF6, LiCF3SO3, LiC(CF3SO2)3, LiC(FSO2)3, LiN(SO2C2F5)2, LiN(SO2CF3)2, LiN(SO2F)2, LiSbF6, LiPF3(CF2CF3)3, LiPF3(CF3)3, and LiB(C2O4)2.

[0225] The concentration of the lithium salt may be, for example, 1 to 5 M, for example, 1 to 2.5 M, in the liquid electrolyte. In the above range, a sufficient amount of lithium ions required for charging and discharging a lithium metal battery can be generated.

[0226] [Separator]

[0227] Depending on the type of lithium secondary battery, a separator may exist between the positive and negative electrode current collectors.

[0228] The pore diameter of the separator is generally 0.01 to 10 μm, and the thickness can generally be 5 to 20 μm. Examples of such separators include sheets or non-woven fabrics made of olefin-based polymers such as polypropylene, glass fiber, or polyethylene. When a solid polymer electrolyte is used as the electrolyte, the solid polymer electrolyte may also function as the separator.

[0229] The above separator may include a porous substrate and a coating layer including an organic material, an inorganic material, or a combination thereof located on one or both sides of the porous substrate.

[0230] Forming a coating layer can improve cell performance in lithium secondary batteries by suppressing lithium dendrite formation through the rigidity of the ceramic coating layer without significantly increasing cell resistance. Furthermore, employing a separator having the aforementioned ceramic coating layer ensures heat resistance, thereby improving heat shrinkage characteristics and reducing the material cost of lithium secondary batteries by reducing the separator margin for safety during cell design. Furthermore, by physically suppressing dendrite growth on the negative electrode, long-term lifespan at both room and high temperatures can be improved.

[0231] The porous substrate may be, for example, a porous membrane. The porous membrane may be, for example, a microporous membrane. The porous membrane may be, for example, a woven fabric or a non-woven fabric. The porous membrane may be any material commonly used in lithium batteries. The porous membrane may include, for example, glass fiber, an olefin-based resin, a fluoropolymer, an ester-based resin, an imide-based resin, an acrylic resin, a cellulose-based resin, or a combination thereof. The olefin-based resin may include, for example, polyethylene, polypropylene, or a combination thereof. The fluoropolymer-based resin may include, for example, polyvinylidene fluoride, polytetrafluoroethylene, or a combination thereof. The ester-based resin may include, for example, polyethylene terephthalate, polybutylene terephthalate, or a combination thereof. The imide-based resin may include, for example, polyamideimide, polyetherimide, or a combination thereof. Acrylic resins may include, for example, polyacrylonitrile, polyacrylate, or combinations thereof. Cellulosic resins may include, for example, carboxymethylcellulose, microbial cellulose, plant cellulose, animal cellulose, or combinations thereof.

[0232] The above porous substrate may be a polymer film formed of any one polymer selected from polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyacetal, polyamide, polyimide, polycarbonate, polyether ketone, polyarylether ketone, polyetherimide, polyamideimide, polybenzimidazole, polyethersulfone, polyphenylene oxide, cyclic olefin copolymer, polyphenylene sulfide, polyethylene naphthalate, glass fiber, Teflon, and polytetrafluoroethylene, or a copolymer or mixture of two or more thereof.

[0233] The organic material may include a polyvinylidene fluoride polymer or a (meth)acrylic polymer.

[0234] The above inorganic materials are Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, SrTiO3, BaTiO3, Mg(OH)2, boehmite, AIN (Aluminum Nitride), SiC (Silicon Carbide), BoN (Boron Nitride), BaTiO3, Pb(Zr,Ti)O3 (PZT), Pb 1-a La a Zr 1-b Ti b O3 (PLZT, where, 0 <a<1, 0<b<1임), Pb(Mg 1 / 3 Nb 2 / 3 )O3-PbTiO3 (PMN-PT), hafnia (HfO2), SrTiO3, SiC, lithium phosphate (Li3PO4), lithium titanium phosphate (Li c Ti d (PO4)3, 0 <d<2, 0<d<3), 리튬알루미늄티타늄포스페이트 (Li a1 Al b1 Ti c1 (PO4)3, 0 <a1<2, 0<b1<1, 0<c1<3), 14Li2O-9Al2O3-38TiO2-39P2O5 등과 같은 (LiAlTiP) a2 O b2 Series Glass (0) <a2<4, 0<b2<13), 리튬란탄티타네이트 (Li a3 La b3 TiO3, 0 <a3<2, 0<b3<3), Li 3.25 Ge 0.25 P 0.75 Lithium germanium thiophosphate (Li) such as S4 a4 Ge b4 P c2 S d , 0 <a4<4, 0<b4<1, 0<c2<1, 0<d<5), Li3N 등과 같은 리튬나이트라이드 (Li a5 N b5, 0 <a5<4, 0<b5<2), Li3PO4-Li2S-SiS2 등과 같은 SiS2 계열 글래스 (Li a6 Si b6 S c3 , 0 <a6<3, 0<b6<2, 0<c4<4), LiI-Li2S-P2S5 등과 같은 P2S5 계열 글래스 (Li a7 P b7 S c5 , 0 <a7<3, 0<b7<3, 0<c5<7) 또는 이들의 조합에서 선택되는 무기 입자를 포함할 수 있으나, 이에 한정되는 것은 아니다.

[0235] The organic and inorganic substances may be mixed and present in one coating layer, or a coating layer including an organic substance and a coating layer including an inorganic substance may be present in a laminated form.

[0236] 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.

[0237] Manufacturing Example 1: ZIF-8 (Zeolitic-imidazolate framework-8) (average particle size: 600 nm) (pore volume: 0.03 cm 3 Manufacturing of / g)

[0238] The ratio of Zn precursor Zn(NO3)2·6H2O and monomer including 2-imidazole were controlled and dissolved in DMF to obtain a mixture. The molar ratio of Zn precursor Zn(NO3)2·6H2O and 2-imidazole in the mixture was 1:4. The mixture was slowly stirred for 24 h to separate ZIF from the mixture containing ZIF and dried in an oven at 70°C to obtain ZIF-8 (average particle size: 600 nm) (pore volume: 0.03 cm 3 / g) was manufactured. Here, the average pore size of the composite pores is 0.1 to 50 nm, for example, about 10 nm.

[0239] Manufacturing Example 2: ZIF-8 (Zeolitic-imidazolate framework-8) (average particle size: 200 nm) (pore volume: 0.06 cm 3 Manufacturing of / g)

[0240] ZIF-8 (average particle size: 200 nm) (pore volume: 0.06 cm) was prepared in the same manner as in Manufacturing Example 1, except that the mixing molar ratio of Zn(NO3)2·6H2O and imidazole was changed to 1:10. 3 / g) was manufactured. Here, the average pore size of the composite pores is 0.1 to 50 nm, for example, about 15 nm.

[0241] Manufacturing Example 3: ZIF-8 (Zeolitic-imidazolate framework-8) (particle size: less than 100 nm) (pore volume: 0.08 cm 3 Manufacturing of / g)

[0242] ZIF-8 (particle size: less than 100 nm) (pore volume: 0.08 cm) was prepared in the same manner as in Manufacturing Example 2, except that the mixing molar ratio of Zn(NO3)2·6 H2 O and imidazole was controlled to 1:15 and n-butalamine was additionally mixed in the same molar ratio as that of imidazole. 3 / g) was manufactured. Here, the average pore size of the composite pores is 0.1 to 50 nm, for example, about 20 nm.

[0243] Manufacturing Example 4: ZIF-8 (Zeolitic-imidazolate framework-8) (average particle size: 1 μm) (pore volume: 0.02 cm 3 Manufacturing of / g)

[0244] ZIF-8 (average particle size: 1 μm) (pore volume: 0.02 cm) was prepared in the same manner as in Manufacturing Example 2, except that the mixing molar ratio of Zn(NO3)2·6 H2O and imidazole was changed to 1:2. 3 / g) was manufactured. Here, the average pore size of the composite pores is 50 nm or less, for example, 0.1 to 50 nm.

[0245] Manufacturing Example 5: ZIF-8 (Zeolitic-imidazolate framework-8) (average particle size: 1.5 μm or more) (pore volume: 0.009 cm 3 / g) manufacturing

[0246] Except that the mixing molar ratio of Zn(NO3)2·6H2O and imidazole was changed to 1:1, the same procedure as in Manufacturing Example 2 was carried out to produce ZIF-8 (average particle size: 1.5 μm or more) (pore volume: 0.009 cm 3 / g) was manufactured. Here, the average pore size of the composite pores is 50 nm or less, for example, 0.1 to 50 nm.

[0247] Manufacturing Example 6: Manufacturing of PVA-PIF (polyvinyl alcohol and fluorinated polyamic acid-containing polymer of the following chemical formula 10) solution

[0248] Polyvinyl alcohol was purchased from Sigma-Aldrich. The synthesis process of fluorinated polyamic acid of chemical formula 10 is as follows.

[0249] First, after filling a round-bottomed flask with nitrogen, 4.9411 g (0.00154 mol) of 2,2'-bis(trifluoromethyl)benzidine (TFDB) and 0.7825 g (0.00051 mol) of diaminobenzoic acid (DABA) were added, followed by adding 131 g of N-methylpyrrolidone (NMP) and completely dissolving using a mechanical stirrer. Next, 9.2764 g (0.0209 mol) of 4,4'-(hexafluoroisopropylidene) (6FDA) was added and stirred at room temperature for 24 hours, thereby producing a polyamic acid represented by the following chemical formula 9. The polyamic acid is a random copolymer. The molar ratio of 6FDA:TFDB:DABA was 4:3:1.

[0250] In chemical formula 9, the molar ratio of n:m was 1:3.

[0251] 10 g of LiOH aqueous solution having 0.5 equivalents in carboxylic acid equivalent ratio was added to polyamic acid (6FDA:TFDB:DABA, acid equivalent 210 g / eq) represented by the following chemical formula 9, and 0.5 equivalents of COOH among the COOH of polyamic acid was converted to COO-Li + A water-soluble polyamic acid represented by the chemical formula 10 substituted with was prepared.

[0252] [Chemical Formula 9]

[0253]

[0254] In the above equation, n is 0.25, m is 0.75, and the sum of n and m is 1.

[0255] A water-soluble polyamic acid represented by the following chemical formula 10 and polyvinyl alcohol (weight average molecular weight, Mw = 89,000, hydrolysis +99%) were mixed in a weight ratio of 20:80 to prepare a polymer solution having a solid content of 10 wt%.

[0256] [Chemical Formula 10]

[0257]

[0258] In the above equation, n is 0.25, m is 0.75, and the sum of n and m is 1.

[0259] Manufacturing Example 7: Manufacturing of MOF

[0260] ZrCl4 (18.64 mg) and an organic ligand compound represented by the following chemical formula 3 (19.536 mg) were each dispersed in 5 ml of DMF solvent. Next, acetic acid (1.38 ml) was added to the ZrCl4-containing solution, and triethylamine (TEA) (30 μl) was added to the organic ligand compound-containing solution, and then mixed.

[0261] Thereafter, the ZrCl4-containing solution and the organic ligand compound-containing solution were mixed and placed in an oven at 85°C and heated for 12 hours. To remove impurities within the pores, washing was performed three times each with DMF and methanol, and vacuum-dried at 60°C to produce a metal-organic framework material (hereinafter referred to as M-bpyN).

[0262] [Chemical Formula 3]

[0263]

[0264] Example 1: Lithium host layer (ZIF-8 + binder (PVA-PIF) + conductive material (carbon black) = 8:1:1) (average particle diameter of ZIF-8: 600 nm, pore volume of ZIF-8: 0.03 cm 3 / g), binder content: 10 wt%, porosity of lithium host layer: 40%

[0265] A 10 μm thick Cu foil was prepared as a negative electrode current collector. In addition, as a lithium host,

[0266] NMP was added to ZIF-8 (average particle size 600 nm) obtained according to Manufacturing Example 1, carbon black as a conductive material, and PVA-PIF as a binder obtained according to Manufacturing Example 2, and the mixture was milled in a ball mill to prepare a slurry. The weight ratio of the ZIF, conductive material, and binder of Manufacturing Example 1 was 8:1:1. In addition, the total solid content in the slurry was 45 parts by weight, and the content of NMP was 55 parts by weight.

[0267] The above slurry was cast onto a Cu foil and dried in an oven at 80°C. Subsequently, heat treatment was performed at 180°C for 30 minutes to harden the binder, thereby forming a lithium host layer with a thickness of approximately 40 μm on the negative electrode current collector, thereby preparing a laminate. The porosity of the lithium host layer was approximately 30%.

[0268] The carboxyl group of the polyamic acid of chemical formula 10 manufactured according to Manufacturing Example 5 through the above heat treatment reacts with the hydroxyl group of polyvinyl alcohol to form an ester linker, thereby forming a crosslinked polymer (PVA / PI-F) of polyimide and polyvinyl alcohol of chemical formula 12 below. The crosslinked polymer had a three-dimensional network structure in which the polyimide of chemical formula 12 and polyvinyl alcohol were crosslinked at multiple points. The weight average molecular weight of the crosslinked polymer was 200,000 to 300,000 Dalton.

[0269] [Chemical Formula 12]

[0270]

[0271] In chemical formula 12, n is 0.25, m is 0.75, and the weight average molecular weight of the polyimide of chemical formula 12 is approximately 2,000,000.

[0272] A polyethylene single film with a thickness of 20 μm was laminated as a separator, and a positive electrode was laminated on the other side of the separator to manufacture a laminate. A liquid electrolyte was injected into the prepared laminate to manufacture a lithium metal battery. The lithium metal battery had a structure of positive electrode / electrolyte / separator / lithium host layer / negative electrode current collector. The liquid electrolyte was used in which 0.6 M LiBF4 and 0.6 M LiDFOB (lithium difluoro(oxalate)borate) were added to a 2:1 volume ratio mixed solvent of diethyl carbonate (DEC) and fluoroethylene carbonate (FEC).

[0273] The above anode was manufactured according to the following method.

[0274] Li 1.04 Ni 0.88 Co 0.1 Al 0.02O2 powder and carbon conductive material (Super-P; Timcal Ltd.) were uniformly mixed at a weight ratio of 90:5, and then a PVDF (polyvinylidene fluoride) binder solution was added to prepare a positive electrode active material slurry with a weight ratio of active material:carbon conductive material:binder = 90:5:5.

[0275] The manufactured slurry was coated on a 15 ㎛ thick aluminum substrate using a doctor blade, dried under reduced pressure at 120°C, and rolled using a roll press to form a sheet to manufacture a positive electrode.

[0276] In the lithium metal battery manufactured according to the above process, lithium was deposited on the lithium host layer before and after charging and discharging.

[0277] Example 2: Lithium host layer (ZIF-8 + binder (PVA-PIF) + conductive material (carbon black) = 8:1:1) (average particle size of ZIF-8: 200 nm, pore volume of ZIF-8: 0.06 cm 3 / g), binder content: 10 wt%, porosity of lithium host layer: approximately 40%

[0278] A lithium metal battery was manufactured in the same manner as in Example 1, except that ZIF-8 of Manufacturing Example 2 was used instead of ZIF-8 of Manufacturing Example 1 when manufacturing the slurry.

[0279] Example 3: Lithium host layer (ZIF-8 + binder (PVA-PIF) + conductive material (carbon black) = 8:1.3:0.7) (average particle size of ZIF-8: 200 nm, pore volume of ZIF-8: 0.06 cm 3 / g), binder content: 13 wt%, porosity of lithium host layer: approximately 40%

[0280] A lithium metal battery was manufactured in the same manner as Example 2, except that the binder content of Manufacturing Example 2 was changed to 13 wt% and the conductive material content was changed to 7 wt% during the slurry manufacturing process.

[0281] Example 4: Lithium host layer (ZIF-8 + binder (PVdF) + conductive material (carbon black) = 8:1:1) (average particle size of ZIF-8: 200 nm, pore volume of ZIF-8: 0.06 cm 3 / g), binder content: 10 wt%, porosity of lithium host layer: approximately 40%

[0282] A lithium metal battery was manufactured in the same manner as in Example 2, except that a PVdF binder was used instead of the PVA-PIF binder of Manufacturing Example 2 when manufacturing the slurry.

[0283] Example 5: Lithium host layer (ZIF-8 + binder (PVA-PIF) + conductive material (carbon black) = 8:1:1) (average particle size of ZIF-8: 1 μm, pore volume of ZIF-8: 0.02 cm 3 / g), binder content: 10 wt%, porosity of lithium host layer: approximately 40%

[0284] A lithium metal battery was manufactured in the same manner as in Example 1, except that ZIF-8 of Manufacturing Example 4 was used instead of ZIF-8 of Manufacturing Example 1 when manufacturing the slurry.

[0285] Example 6: Thickness of lithium host layer: 80 μm (lithium host layer (ZIF-8 + binder (PVA-PIF) + conductive material (carbon black) = 8:1:1) (average particle size of ZIF-8: 200 nm, pore volume of ZIF-8: 0.06 cm) 3 / g), porosity of lithium host layer: approximately 40%

[0286] A lithium metal battery was manufactured in the same manner as in Example 4, except that a lithium host layer was formed with a thickness of approximately 80 μm on the negative electrode current collector using ZIF-8 of Manufacturing Example 2 to prepare a laminate.

[0287] Example 7: Lithium host layer (ZIF-8 + binder (PVA-PIF) + conductive material (carbon black) = 8:1:1) (average particle size of ZIF-8: 200 nm, pore volume of ZIF-8: 0.06 cm 3 / g), binder content: 10 wt%, porosity of lithium host layer: approximately 70%

[0288] A lithium metal battery was manufactured in the same manner as in Example 4, except that a lithium host layer was cast on a negative electrode current collector using ZIF-8 of Manufacturing Example 2, and the porosity of the lithium host layer was prepared to be 70%.

[0289] Example 8: Lithium host layer (ZIF-8 + binder (PVA-PIF) + conductive material (carbon black) = 8:1:1) (average particle size of ZIF-8: 200 nm, pore volume of ZIF-8: 0.06 cm 3 / g), binder content: 10 wt%, porosity of lithium host layer: approximately 60%

[0290] A lithium metal battery was manufactured in the same manner as in Example 4, except that a lithium host layer was cast on a negative electrode current collector using ZIF-8 of Manufacturing Example 2, and the porosity of the lithium host layer was prepared to be 60%.

[0291] Example 9: Lithium host layer (ZIF-8 + binder (PVA-PIF) + conductive material (carbon black) = 8:1:1) (average particle diameter of ZIF-8: 200 nm, pore volume of ZIF-8: 0.06 cm 3 / g), binder content: 10 wt%, porosity of lithium host layer: approximately 50%

[0292] A lithium metal battery was manufactured in the same manner as in Example 4, except that a lithium host layer was cast on a negative electrode current collector using ZIF-8 of Manufacturing Example 2, and the porosity of the lithium host layer was prepared to be 50%.

[0293] Comparative Example 1: Using Bare Cu, Lithium Host Layer Free

[0294] A lithium metal battery was manufactured in the same manner as in Example 2, except that a lithium host layer was not formed on the negative electrode current collector.

[0295] Comparative Example 2: Lithium host layer (ZIF-8 + binder (PVA-PIF) + conductive material (carbon black) = 8:1:1) (average particle size: 1.5 μm or more) (composite pore volume: 0.009 cm 3 / g)

[0296] In the slurry manufacturing process, instead of ZIF-8 of Manufacturing Example 1, ZIF-8 manufactured according to Manufacturing Example 5 (average particle size: 1.5 μm or more) (composite pore volume: 0.009 cm 3 A lithium metal battery was manufactured in the same manner as in Example 1, except that / g) was used.

[0297] Comparative Example 3: Use of nonporous ZnO material

[0298] A lithium metal battery was manufactured in the same manner as Example 1, except that ZnO, a non-porous material, was used instead of ZIF-8 in Manufacturing Example 1 when manufacturing the slurry.

[0299] Comparative Example 4: Lithium Host Layer: Without Binder

[0300] A lithium metal battery was manufactured in the same manner as in Example 1, except that no binder was used in the manufacture of the lithium host layer.

[0301] Comparative Example 5: Using MOF instead of ZIF

[0302] A lithium metal battery was manufactured in the same manner as in Example 1, except that the metal-organic framework material (M-bpyN) manufactured according to Manufacturing Example 7 was used instead of ZIF-8 of Manufacturing Example 1 when manufacturing the slurry.

[0303] The metal-organic framework material of Comparative Example 5 contains an oxygen-containing organic ligand, which reduces stability at high voltage and high temperature.

[0304] Comparative Example 6: Porosity of lithium host layer: less than 30% (average particle size of ZIF-8: 200 nm, composite pore volume: 0.06 cm 3 / g), binder content: 10 wt, 40 ㎛ thickness, porosity of lithium host layer: 20%

[0305] A lithium metal battery was manufactured in the same manner as in Example 2, except that a lithium host layer was cast on a negative electrode current collector using ZIF-8 of Manufacturing Example 2, and the porosity of the lithium host layer was prepared to be 20%.

[0306] Comparative Example 7: Porosity of lithium host layer: less than 30% (average particle size of ZIF-8: 200 nm, composite pore volume: 0.06 cm 3 / g), binder content: 10 wt, 40 μm thickness, porosity of lithium host layer: 80%

[0307] A lithium metal battery was manufactured in the same manner as in Example 2, except that a lithium host layer was cast on a negative electrode current collector using ZIF-8 of Manufacturing Example 2, and the porosity of the lithium host layer was prepared to be 80%.

[0308] The area of ​​the lithium host layer of the above Example 1-8 and Comparative Example 2-6 was 6 cm3, the thickness was 40 um, and the porosity of the lithium host layer was measured according to the following Equations 1 and 2.

[0309] <Formula 1>

[0310] Porosity of lithium host layer = {(total volume of lithium host layer - total volume of lithium host layer components) / total volume of lithium host layer} x 100

[0311] In Equation 1, the total volume of the lithium host layer (cm 3 ) = area of ​​lithium host layer (cm2) x thickness of lithium host layer (cm), and the volume of components of lithium host layer can be expressed by Equation 2 below.

[0312] <Formula 2>

[0313] Volume of components of the lithium host layer (cm) 3 ) = (Weight of components of lithium host layer (g) * Ratio of components of lithium host layer in lithium host layer) / Total density of components of lithium host layer (g / cm3)

[0314] The components of the lithium host layer refer to the components that constitute the lithium host layer, and refer to a metal-organic framework, a conductive material, and a binder.

[0315] Evaluation Example 1: Scanning Electron Microscope (SEM) Analysis

[0316] SEM analysis was performed on the ZIF-8 structures manufactured according to Manufacturing Examples 1 and 2. The analysis results are shown in Figs. 1a and 1b, respectively.

[0317] Referring to FIGS. 1a and 1b, it was found that the ZIF-8 structure of Manufacturing Example 2 had a smaller particle size than the ZIF-8 structure of Manufacturing Example 1, and lithium was deposited in a cluster type between the pores and particles within the lithium host layer.

[0318] Evaluation Example 2: Charge / Discharge Characteristics

[0319] A half-cell was manufactured by stacking a separator and lithium metal on the negative electrode current collector / lithium host layer laminate obtained according to Example 1 and Example 2, and on the bare Cu of Comparative Example 1, and injecting an electrolyte.

[0320] The above half-cell was charged at a constant current of 0.1 C rate at 25°C until the voltage reached 4.3 V (vs. Li), and then cut-off was achieved at a current of 0.05 C rate while maintaining 4.3 V in constant voltage mode. Subsequently, the cell was discharged at a constant current of 0.1 C rate until the voltage reached 3.6 V (vs. Li). The potential change according to capacity during this cycle was investigated and is shown in Fig. 2.

[0321] Referring to FIG. 2, it was found that the half-cells containing the negative electrode collector / lithium host layer laminates of Examples 1 and 2 had a reduced first charge overvoltage compared to the half-cells containing the laminate using bare Cu of Comparative Example 1.

[0322] Evaluation Example 3: Lifespan at room temperature (25℃)

[0323] The charge / discharge characteristics of the lithium metal batteries of Example 1-9 and Comparative Example 1-7 were evaluated under the following conditions.

[0324] The battery was charged at a constant current of 0.1 C rate at 25°C until the voltage reached 4.3 V (vs. Li), and then cut-off at a current of 0.05 C rate while maintaining 4.3 V in constant voltage mode. Subsequently, the battery was discharged at a constant current of 0.1 C rate until the voltage reached 3.6 V (vs. Li) (formation cycle).

[0325] The lithium metal battery, which had undergone a Mars cycle, was charged at a constant current of 0.2 C rate at 25°C until the voltage reached 4.3 V (vs. Li), and then cut-off at a current of 0.05 C rate while maintaining 4.3 V in constant voltage mode. Subsequently, the battery was discharged at a constant current of 0.5 C rate until the voltage reached 3.6 V (vs. Li) (1 st cycle). These cycles are 100 th The cycle was repeated under the same conditions.

[0326] In all charge / discharge cycles, a 10-minute pause was observed after each charge / discharge cycle. Some of the results of the room-temperature charge / discharge experiments are shown in Table 1 and Figure 3. The cycle number refers to the number of cycles required for the discharge capacity to decrease to 80% of the standard capacity after the second cycle. As the cycle number increases, the battery is considered to have better life characteristics.

[0327] Evaluation Example 4: High-rate characteristics

[0328] The lithium batteries manufactured in Example 1-7 and Comparative Example 1-7 were charged at a constant current of 0.1 C rate at 25°C until the voltage reached 4.3 V (vs. Li), and then cut-off at a current of 0.05 C rate while maintaining 4.3 V in constant voltage mode. Subsequently, the batteries were discharged at a constant current of 0.1 C rate until the voltage reached 3.6 V (vs. Li) during discharge (formation cycle).

[0329] The lithium battery that had undergone the Mars cycle was charged at a constant current of 0.2 C rate at 25°C until the voltage reached 4.3 V (vs. Li), and then cut-off at a current of 0.05 C rate while maintaining 4.3 V in constant voltage mode. Subsequently, the battery was discharged at a constant current of 0.2 C rate until the voltage reached 3.6 V (vs. Li) (4 st cycle).

[0330] 1 st The cycled lithium battery was charged at a constant current of 0.2 C at 25°C until the voltage reached 4.3 V (vs. Li), and then cut off at a current of 0.05 C while maintaining 4.3 V in constant voltage mode. Subsequently, the battery was discharged at a constant current of 0.5 C until the voltage reached 2.8 V (vs. Li) (5 st cycle).

[0331] 5 nd Cycle 9 th The cycle was repeated under the same conditions.

[0332] 7 thThe cycled lithium battery was charged at a constant current of 0.33 C at 25°C until the voltage reached 4.35 V (vs. Li), and then cut off at a current of 0.05 C while maintaining 4.35 V in constant voltage mode. Subsequently, the battery was discharged at a constant current of 3 C until the voltage reached 2.8 V (vs. Li) (13 st cycle).

[0333] 8th cycle 18 th The cycle was repeated under the same conditions.

[0334] 17 th The cycled lithium battery was charged at a constant current of 0.33 C at 25°C until the voltage reached 4.35 V (vs. Li), and then cut off at a current of 0.05 C while maintaining 4.35 V in constant voltage mode. Subsequently, the battery was discharged at a constant current of 3 C until the voltage reached 2.8 V (vs. Li) (19 th cycle).

[0335] 19 th Cycle 23 th The cycle was repeated under the same conditions.

[0336] 23 st The cycled lithium battery was charged at a constant current of 0.33 C at 25°C until the voltage reached 4.35 V (vs. Li), and then cut off at a current of 0.05 C while maintaining 4.35 V in constant voltage mode. Subsequently, the battery was discharged at a constant current of 0.2 C until the voltage reached 2.8 V (vs. Li) (24 th cycle).

[0337] 24 stThe cycled lithium battery was charged at a constant current of 0.33 C at 25°C until the voltage reached 4.35 V (vs. Li), and then cut off at a current of 0.05 C while maintaining 4.35 V in constant voltage mode. Subsequently, the battery was discharged at a constant current of 0.5 C until the voltage reached 2.8 V (vs. Li) (25 th Cycle). 25 th Cycle 30 th The cycle was repeated under the same conditions.

[0338] In all the above charge / discharge cycles, a pause of 10 minutes was allowed after each charge / discharge cycle.

[0339] Some of the results of the above charge-discharge experiment are shown in Table 1 below.

[0340] The high-rate characteristic is defined by Equation 3 below.

[0341] <Formula 3>

[0342] High rate characteristic [%] = [23 st Discharge capacity in cycle (3C rate) / 2 nd Discharge capacity in cycle (0.2C rate)] × 100

[0343] Distinction Conditions Life High Rate Characteristics Example 1 Lithium host layer (ZIF-8 + binder (PVA-PIF) + conductive material (carbon black) = 8:1:1) (average particle size of ZIF-8: 600 nm, pore volume of ZIF-8: 0.03 cm3 / g), binder content: 10 wt %, porosity of lithium host layer: 40% 75% 45% Example 2 Lithium host layer (ZIF-8 + binder (PVA-PIF) + conductive material (carbon black) = 8:1:1) (average particle size of ZIF-8: 200 nm, pore volume of ZIF-8: 0.06 cm3 / g), binder content: 10 wt %, porosity of lithium host layer: 40% 78% 47% Example 3Lithium host layer (ZIF-8+binder (PVA-PIF)+conductive material (carbon black)=8:1:1) (average particle size of ZIF-8: 200 nm, pore volume of ZIF-8: 0.06 cm3 / g), binder content: 13 wt %, porosity of lithium host layer: 40%83%53%Example 4Lithium host layer (ZIF-8+binder (PVdF)+conductive material (carbon black)=8:1:1) (average particle size of ZIF-8: 200 nm, pore volume of ZIF-8: 0.06 cm3 / g), binder content: 10 wt %, porosity of lithium host layer: 40%75%42%Example 5 Lithium host layer (ZIF-8 + binder (PVA-PIF) + conductive material (carbon black) = 8:1:1) (average particle size of ZIF-8: 1 μm, pore volume of ZIF-8: 0.02 cm3 / g), binder content: 10 wt %, porosity of lithium host layer: 40% 71% 41% Example 6 Lithium host layer (ZIF-8 + binder (PVA-PIF) + conductive material (carbon black) = 8:1:1) (average particle size of ZIF-8: 200 nm, pore volume of ZIF-8: 0.06 cm3 / g), binder content: 10 wt %, host layer thickness: 80 μm, porosity of lithium host layer: 40%72%42%Example 7Lithium host layer (ZIF-8+binder (PVA-PIF)+conductive material (carbon black)=8:1:1) (Average particle size of ZIF-8: 200 nm, pore volume of ZIF-8: 0.06 cm 3 / g), binder content: 10 wt%, porosity of lithium host layer: about 70%61%40%Comparative Example 2 Lithium host layer (ZIF-8+binder(PVA-PIF)+conductive material(carbon black)=8:1:1) (average particle size of ZIF-8: 1.5㎛, pore volume of ZIF-8: 0.009 cm3 / g), binder content: 10 wt%49%30%Comparative Example 3 Nonporous ZnO material48%25%Comparative Example 4 Lithium host layer: without binder33%17%Comparative Example 5 Using MOF47%23%Comparative Example 6 Lithium host layer (ZIF-8+binder(PVA-PIF)+conductive material(carbon black)=8:1:1) (average particle size of ZIF-8: 200nm, pore volume of ZIF-8 Volume: 0.06 cm3 / g), binder content: 10 wt %, host layer porosity 30%48%25%Comparative Example 7 Lithium host layer (ZIF-8+binder (PVA-PIF)+conductive material (carbon black)=8:1:1) (average particle size of ZIF-8: 200 nm, pore volume of ZIF-8: 0.06 cm3 / g), binder content: 10 wt %, host layer porosity 80%)28%14%

[0344] As shown in Table 1, the lithium metal batteries of Examples 1 to 7 had improved life characteristics and high-rate characteristics compared to the lithium metal batteries of Comparative Examples 2 to 7.

[0345] Referring to Figure 3, it can be confirmed that the lithium metal batteries of Examples 2 and 3 exhibit excellent life characteristics. Among them, when the lithium host layer is formed, the average particle diameter is 200 nm and the pore volume is 0.06 cm. 3 The lithium metal battery of Example 3 using ZIF-8 of / g and having a porosity of 40% in the lithium host layer showed the best results in terms of life characteristics and high-rate characteristics.

[0346] Although not shown in Table 1, the lithium metal batteries of Examples 8 and 9 exhibited similar life and high-rate characteristics to the lithium metal battery of Example 6.

[0347] Although not shown in Table 1, the lithium metal battery of Comparative Example 1 had a lower high-rate (2C discharge) characteristic compared to the lithium metal batteries of Examples 1 to 9.

[0348] While exemplary embodiments have been described in detail with reference to the attached drawings, the present invention is not limited to these examples. It is self-evident that those skilled in the art to which the present invention pertains can devise various modifications or variations within the scope of the technical concepts described in the patent claims, and these also naturally fall within the technical scope of the present invention.

Claims

1. A lithium metal battery comprising a positive electrode layer; a negative electrode current collector; and an electrolyte disposed between the positive electrode layer and the negative electrode current collector. The above positive electrode layer includes a positive electrode current collector and a positive electrode active material layer disposed on one or both sides of the positive electrode current collector, It includes a lithium host layer disposed on one surface of the above negative electrode collector, The above lithium host layer contains a lithium-affinity metal-organic framework including a lithium-affinity transition metal and an imidazole-based organic ligand and a binder, The lithium-affinity transition metal is zinc (Zn), gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), nickel (Ni), manganese (Mn), cobalt (Co), or a combination thereof. The pore volume of the above metal-organic framework is 0.01 cm 3 / g or more, The above lithium host layer further includes pores, A lithium metal battery, wherein the porosity of the lithium host layer is 40% to 70%.

2. In the first paragraph, the pore volume of the metal-organic framework structure is 0.01 to 1.0 cm 3 / g, A lithium metal battery, wherein the particle size of the lithium-affinity metal-organic framework structure is 50 nm to 3 um.

3. A lithium metal battery according to claim 1, wherein the imidazole-based organic ligand of the lithium-affinity metal-organic framework structure comprises imidazole, 2-methylimidazole, 4-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, benzimidazole, methylbenzimidazole, 1-methyl-1H-imidazole, N-methylimidazole, or a combination thereof.

4. A lithium metal battery according to claim 1, wherein the lithium-affinity metal-organic framework structure comprises a ZIF (Zeolitic-imidazolate framework) carbon-based nanostructure.

5. A lithium metal battery according to claim 1, wherein the pore size of the lithium-affinity metal-organic framework structure is 0.1 to 300 nm.

6. A lithium metal battery according to claim 1, wherein the thickness of the lithium host layer is 20 ㎛ to 300 ㎛.

7. A lithium metal battery in which a lithium precipitation layer is absent between the negative electrode current collector and the lithium host layer in the first paragraph.

8. A lithium metal battery in the first paragraph, wherein the content of the binder in the lithium host layer is 1 to 15 wt% based on the total weight of the lithium host layer.

9. A lithium metal battery in the first paragraph, wherein the binder in the lithium host layer further includes a first polymer containing a hydroxyl group and a second polymer having a crosslinkable functional group.

10. A lithium metal battery according to claim 9, wherein the second polymer is at least one selected from among fluorinated polyamic acid and fluorinated polyimide having a carboxyl group.

11. In the 9th paragraph, the first polymer containing a hydroxyl group is carboxymethyl cellulose (CMC); polyvinyl alcohol (PVA); Vinyl acetate, butyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 2-hydroxyethylene glycol (meth)acrylate, 2-hydroxypropylene glycol (meth)acrylate, acrylic acid, methacrylic acid, 2-(meth)acryloyloxy acetic acid, 3-(meth)acryloyloxy propyl acid, 4-(meth)acryloyloxy butyric acid, itaconic acid, maleic acid, 2-isocyanatoethyl (meth)acrylate, 3-isocyanatopropyl (meth)acrylate, A lithium metal battery, which is a polymerization reaction product of one or more monomers selected from among 4-isocyanatobutyl (meth)acrylate, (meth)acrylamide, ethylene di(meth)acrylate, diethylene glycol (meth)acrylate, triethylene glycol di(meth)acrylate, trimethylene propane tri(meth)acrylate, trimethylene propane triacrylate, 1,3-butanediol (meth)acrylate, 1,6-hexanediol di(meth)acrylate, allyl acrylate, and N-vinyl caprolactam, or a hydrolyzate thereof.

12. A lithium metal battery according to claim 9, wherein the second polymer is a polyamic acid represented by the following chemical formula 9 or 10, a polyimide represented by the following chemical formula 11 or 12, or a combination thereof: [Chemical Formula 9] [Chemical Formula 10] [Chemical Formula 11] [Chemical Formula 12] In the above equations, n and m are the mole fractions within the repeating unit, respectively, and 0 <n≤1, 0≤m<1, n+m=1이다.

13. A lithium metal battery according to claim 1, wherein the binder is a vinylidene fluoride-hexafluoropropylene (VDF-HFP) copolymer, polyethylene oxide, polypropylene oxide, polydimethylsiloxane, polyacrylonitrile, polymethyl(meth)acrylate, polyvinyl chloride, polyvinylidene fluoride, polyvinylidene fluoride-co-hexafluoropropylene, polyethyleneimine, polyphenylene terephthalamide, polymethoxypolyethylene glycol(meth)acrylate, poly2-methoxy ethyl glycidyl ether, or a combination thereof.

14. A lithium metal battery according to claim 1, further comprising a metal layer disposed in some or all of the pores after the lithium metal battery is charged.

15. A lithium metal battery according to claim 14, wherein the metal layer comprises lithium metal foil, lithium metal powder, lithium alloy foil, lithium alloy powder, or a combination thereof.

16. In paragraph 15, the lithium alloy contains lithium and a first metal, A lithium metal battery, wherein the first metal is indium (In), silicon (Si), gallium (Ga), tin (Sn), aluminum (Al), titanium (Ti), zirconium (Zr), niobium (Nb), germanium (Ge), antimony (Sb), bismuth (Bi), gold (Au), platinum (Pt), palladium (Pd), magnesium (Mg), silver (Ag), zinc (Zn), nickel (Ni), iron (Fe), cobalt (Co), chromium (Cr), cesium (Cs), sodium (Na), potassium (K), calcium (Ca), yttrium (Y), bismuth (Bi), tantalum (Ta), hafnium (Hf), barium (Ba), vanadium (V), strontium (Sr), lanthanum (La), or a combination thereof.

17. A lithium metal battery in the first paragraph, wherein the thickness of the lithium host layer is greater than 50% of the thickness of the positive electrode active material layer or the thickness of the solid electrolyte layer.

18. In the first paragraph, the electrolyte is a liquid electrolyte, a solid electrolyte, a gel electrolyte, or a combination thereof, The above solid electrolyte includes an oxide-based solid electrolyte, a sulfide-based solid electrolyte, a polymer solid electrolyte, or a combination thereof, A lithium metal battery, wherein the gel electrolyte comprises a polymer gel electrolyte.

19. In the first paragraph, the positive electrode includes a positive electrode current collector and a positive electrode active material layer, At least one of the positive electrode current collector and the negative electrode current collector includes 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 lithium metal 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.

20. A lithium metal battery comprising a first inactive member disposed on one side of the lithium host layer according to claim 1.

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