Lithium metal battery and method for manufacturing lithium metal battery

Abstract

A lithium metal battery and a method for manufacturing a lithium metal battery are presented. The lithium metal battery comprises: a positive electrode; a negative electrode; and an electrolyte layer disposed between the positive electrode and the negative electrode, wherein the negative electrode comprises a negative electrode current collector and an electrodeposition-inducing layer disposed on the negative electrode current collector, and the electrodeposition-inducing layer comprises chromium (Cr).

Description

Lithium metal battery and method for manufacturing lithium metal battery

[0001] It relates to a lithium metal battery and a method for manufacturing a lithium metal battery.

[0002] Lithium batteries currently on the market primarily use carbon-based anode materials, such as graphite. Carbon-based anode materials exhibit no volume change during charge and discharge, contributing to the stability of lithium batteries. Graphite's theoretical capacity is relatively small, at around 372 mAh / g.

[0003] Lithium metal can be used as an anode active material. Lithium metal has a very high theoretical electrical capacity of approximately 3860 mAh / g. During charge / discharge, lithium metal can form dendrites on its surface due to side reactions with the electrolyte. These dendrites can grow and cause short circuits between the anode and cathode. Consequently, the lifespan of lithium metal batteries containing lithium metal deteriorates.

[0004] A method for improving the life characteristics of a lithium metal battery containing lithium metal is required.

[0005] One aspect is to provide a lithium metal battery with a new structure.

[0006] Another aspect is to provide a method for manufacturing a lithium metal battery with a new structure.

[0007] According to the implementation example

[0008] A cathode; an anode; and an electrolyte layer disposed between the anode and the cathode,

[0009] The above cathode

[0010] negative current collector; and

[0011] It includes an electrodeposition induction layer disposed on the above negative electrode collector;

[0012] A lithium metal battery is provided, wherein the electrodeposition-inducing layer includes chromium (Cr).

[0013] According to another implementation example,

[0014] A step of providing a negative electrode collector; and

[0015] A step of providing a cathode by providing an electrodeposition induction layer on the above cathode current collector;

[0016] A step of providing an anode on the cathode and providing an electrolyte layer between the cathode and the anode,

[0017] A method for manufacturing a lithium metal battery is provided, wherein the electrodeposition-inducing layer includes chromium (Cr).

[0018] According to one aspect, it is possible to provide a lithium metal battery with improved overpotential characteristics and cycle characteristics by employing an electrodeposition-inducing layer having a new structure.

[0019] Figure 1 is a cross-sectional view of a cathode according to an exemplary embodiment.

[0020] Figure 2 is a cross-sectional view of a cathode according to another exemplary embodiment.

[0021] Figure 3 is a cross-sectional view of a cathode according to another exemplary embodiment.

[0022] Figure 4 is a cross-sectional view of a cathode according to another exemplary embodiment.

[0023] Figure 5 is a schematic diagram of a lithium metal battery according to an exemplary embodiment.

[0024] Figure 6 is a schematic diagram of a lithium metal battery according to an exemplary embodiment.

[0025] Figure 7 is a schematic diagram of a lithium metal battery according to an exemplary embodiment.

[0026] FIG. 8 is a cross-sectional view of a lithium metal battery including a solid electrolyte layer according to another exemplary embodiment.

[0027] FIG. 9 is a cross-sectional view of a lithium metal battery including a solid electrolyte layer according to another exemplary embodiment.

[0028] Figure 10 is a graph showing the lithium metal battery manufactured in Example 1 and Comparative Example 1. st This is a graph showing the charging curve.

[0029] Figure 11 is 1 of Example 1 st This is a scanning electron microscope image of the cathode cross-section after charging.

[0030] Figure 12 is 1 of Comparative Example 1 st This is a scanning electron microscope image of the cathode cross-section after charging.

[0031] Figure 13 is a graph showing the capacity retention rate for lithium metal batteries manufactured in Example 1, Example 2, Comparative Example 1, Comparative Example 2, and Comparative Example 3.

[0032] During the charge and discharge process of a lithium metal battery using lithium metal as the anode active material, a lithium-containing metal layer is precipitated and dissolved between the anode current collector and the electrolyte layer. As the lithium metal battery is repeatedly charged and discharged, the lithium-containing metal layer includes impurities remaining in the electrode, electrolyte decomposition products, etc. Therefore, the surface of the lithium-containing metal layer becomes rough and hard due to the inclusion of these impurities. Lithium dendrites are precipitated on the lithium-containing metal layer with this rough surface. These lithium dendrites continuously grow during the charge and discharge process, which can cause a short circuit between the positive and negative electrodes.

[0033] According to one aspect, the lithium metal battery has a novel structure, which suppresses the formation of lithium dendrites in the negative electrode current collector or negative electrode active material layer, and the occurrence of short circuits in the lithium metal battery is suppressed through uniform lithium metal deposition, thereby improving the cycle characteristics.

[0034] The present inventive concept described below is capable of various modifications and embodiments. Specific embodiments are illustrated in the drawings and described in detail. However, this is not intended to limit the present inventive concept to specific embodiments, but rather to encompass all modifications, equivalents, or alternatives within the technical scope of the present inventive concept.

[0035] The terminology used below is only used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. Hereinafter, the terms "comprises" or "has" and the like are intended to indicate the presence of a feature, number, step, operation, component, part, ingredient, material, or combination thereof described in the specification, but should be understood to not preclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, ingredients, materials, or combinations thereof. The " / " used below may be interpreted as "and" or "or" depending on the context.

[0036] In order to clearly express various layers and regions in the drawings, the thickness is shown enlarged or reduced. Similar parts are designated by the same drawing reference numerals throughout the specification. When a part such as a layer, film, region, or plate is said to be "on" or "above" another part throughout the specification, this includes not only cases where it is directly above the other part, but also cases where there is another part in between. Terms such as first, second, etc. may be used throughout the specification to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. In this specification and the drawings, components having substantially the same functional configuration are referred to by the same reference numerals, and redundant descriptions are omitted.

[0037] In the present disclosure, the "particle diameter" of a particle refers to the average diameter when the particle is spherical, and refers to the average major axis length when the particle is non-spherical. The particle diameter of a particle can be measured using a particle size analyzer (PSA). The "particle diameter" of a particle is, for example, the average particle diameter. The average particle diameter is, for example, the median particle diameter (D50). The median particle diameter (D50) is the size of a particle corresponding to 50% of the cumulative volume, calculated from the side of particles having a small particle size in a size distribution of particles measured, for example, by laser diffraction.

[0038] In this disclosure, “metal” includes both metals and metalloids such as silicon and germanium, in their elemental or ionic states.

[0039] In this disclosure, “alloy” means a mixture of two or more metals.

[0040] In the present disclosure, “positive electrode material” means a positive electrode material capable of undergoing lithiation and delithiation.

[0041] In the present disclosure, “negative electrode active material” means a negative electrode material capable of undergoing lithiation and delithiation.

[0042] In the present disclosure, “lithiation” and “lithiating” mean a process of adding lithium to a positive electrode active material or a negative electrode active material.

[0043] In the present disclosure, “delithiation” and “delithiate” mean a process of removing lithium from a positive electrode active material or a negative electrode active material.

[0044] In this disclosure, “charging” and “charging” mean a process of providing electrochemical energy to a battery.

[0045] In this disclosure, “discharging” and “discharging” mean the process of removing electrochemical energy from a battery.

[0046] In the present disclosure, “positive electrode” and “cathode” mean an electrode at which electrochemical reduction and lithiation occur during a discharge process.

[0047] In the present disclosure, “cathode” and “anode” mean electrodes where electrochemical oxidation and delithiation occur during a discharge process.

[0048] Hereinafter, a negative electrode for a lithium metal battery, a lithium metal battery including the same, and a method for manufacturing a lithium metal battery according to exemplary embodiments are described in more detail.

[0049] [cathode]

[0050] According to one embodiment, a negative electrode for a lithium metal battery includes: an negative electrode current collector; and an electrodeposition-inducing layer disposed on the negative electrode current collector; wherein the electrodeposition-inducing layer includes chromium (Cr). The electrodeposition-inducing layer including chromium (Cr) may have reduced reactivity with respect to an electrolyte. The electrodeposition-inducing layer including chromium (Cr) may suppress deterioration due to the electrolyte, for example. Side reactions between the electrodeposition-inducing layer including chromium (Cr) and an electrolyte, for example, an electrolyte solution, may be suppressed. The electrodeposition-inducing layer including chromium (Cr) may effectively prevent the generation and / or growth of lithium dendrites on the surface of the electrodeposition-inducing layer or the surface of the negative electrode active material layer. Therefore, the electrodeposition-inducing layer including chromium (Cr) may induce uniform electrodeposition of an negative electrode active material layer including lithium metal formed on the electrodeposition-inducing layer. The stability of a negative electrode including an electrodeposition-inducing layer containing chromium (Cr) and a lithium battery employing the same is improved, and the cycle characteristics of the lithium battery are improved.

[0051] In contrast, an electrodeposition-inducing layer without an electrodeposition-inducing layer or without chromium (Cr) may have increased reactivity toward the electrolyte. A side reaction between an electrodeposition-inducing layer without chromium (Cr) and an electrolyte, such as an electrolyte solution, may be significant. An electrodeposition-inducing layer without chromium (Cr) may have difficulty effectively suppressing the formation and / or growth of lithium dendrites on the surface of a negative electrode active material layer including lithium metal formed on the electrodeposition-inducing layer.

[0052] Referring to FIG. 1, the negative electrode (20) includes a negative current collector (21); a negative active material layer (23) disposed on the negative current collector (21); and an electrodeposition induction layer (22) disposed between the negative current collector (21) and the negative active material layer (23). The electrodeposition induction layer (22) includes chromium (Cr), and the negative active material layer (23) may include lithium metal or a lithium alloy. Referring to FIG. 2, the negative electrode (20) includes a negative current collector (21); a negative active material layer (23) disposed on the negative current collector (21) is free, and an electrodeposition induction layer (22) disposed between the negative current collector (21) and the negative active material layer (23). The electrodeposition induction layer (22) includes chromium (Cr), and the negative active material layer (23) includes lithium metal or a lithium alloy.

[0053] [Cathode: Electrodeposition-inducing layer]

[0054] Referring to FIGS. 1 to 4, the negative electrode (20) includes a negative electrode current collector (21); and an electrodeposition-inducing layer (22) disposed on the negative electrode current collector (21). The electrodeposition-inducing layer (22) includes chromium (Cr). The electrodeposition-inducing layer (22) can effectively prevent the generation and / or growth of lithium dendrites on the surface of the electrodeposition-inducing layer (22) or on the surface of the negative electrode active material layer including lithium metal. Since the electrodeposition-inducing layer (22) including chromium (Cr) does not react with lithium metal, the stability of the lithium battery can be improved.

[0055] The electrodeposition-inducing layer (22) may include chromium (Cr), for example, the electrodeposition-inducing layer (22) may include chromium hydroxide, chromium oxide, or a combination thereof. The chromium hydroxide, chromium oxide, or a combination thereof may include, for example, Cr(OH)3, Cr2O3, CrO3, or a combination thereof. The electrodeposition-inducing layer (22) may be derived from chromate, dichromate, chromic acid, a chromate salt compound, or any combination thereof. The electrodeposition-inducing layer (22) may include composite particles. The composite particles include, for example, a core; and a shell disposed on the core, wherein the core includes the same metal as the negative electrode current collector, and the shell may include chromium (Cr). The shell may be provided, for example, by coating a shell-forming material including chromium (Cr) on the core.

[0056] The electrodeposition-inducing layer (22) may be, for example, polymer-free. Accordingly, by not including a polymer, the electrodeposition-inducing layer (22) may be a polymer-free structure that includes a metal, a solvent, or a combination thereof.

[0057] The particle size of the composite particles may be, for example, 0.5 μm to 10 μm. By including composite particles in this range in the electrodeposition-inducing layer, the lithium dendrite formation suppression properties of the electrodeposition-inducing layer can be further improved.

[0058] The content of chromium (Cr) may be, for example, 0.1 to 10 wt%, 0.5 to 9 wt%, 1 to 8 wt%, 2 to 7 wt%, 3 to 6 wt%, or 4 to 6 wt% based on the total weight of the electrodeposition-inducing layer (22). By including chromium (Cr) in this range in the electrodeposition-inducing layer, the charging characteristics and cycle characteristics of a lithium battery including the electrodeposition-inducing layer can be further improved.

[0059] The chromium deposition amount of the electrodeposition induction layer (22) is, for example, 1.0 mg / m 2 100 mg / m 2 , 5 mg / m 2 80 mg / m 2 , 20 mg / m 2 60 mg / m 2 , or 30 mg / m 2 50 mg / m 2 It may be, but is not necessarily limited to this range and may be adjusted according to the required lithium battery type, capacity, etc.

[0060] The thickness of the electrodeposition-inducing layer (22) may be, for example, 0.01 ㎛ to 5 ㎛, 0.1 ㎛ to 5 ㎛, 0.5 ㎛ to 5 ㎛, 1 ㎛ to 4.5 ㎛, 1.5 ㎛ to 4 ㎛, 2 ㎛ to 3.5 ㎛, or 2.5 ㎛ to 3 ㎛, but is not necessarily limited to this range and may be adjusted according to the required lithium battery shape, capacity, etc. If the thickness of the electrodeposition-inducing layer is too small, it may be difficult to perform the function of the electrodeposition-inducing layer. If the thickness of the electrodeposition-inducing layer is too large, the internal resistance may increase and the energy density of the lithium battery may decrease.

[0061] The thickness ratio of the electrodeposition-inducing layer (22) to the thickness of the negative electrode current collector (21) may be 0.01 to 0.45, 0.05 to 0.45, 0.1 to 0.45, 0.2 to 0.45, 0.3 to 0.45, 0.01 to 0.4, 0.05 to 0.4, 0.1 to 0.4, 0.2 to 0.4, 0.3 to 0.4, but is not necessarily limited to this range and may be adjusted according to the required lithium battery shape, capacity, etc. If the thickness ratio of the electrodeposition-inducing layer is excessively small or increased compared to the thickness of the negative electrode current collector, it may be difficult for the electrodeposition-inducing layer to perform its function.

[0062] Referring to FIGS. 3 and 4, the electrodeposition induction layer (22) can be additionally placed on the side of the negative electrode current collector (21).

[0063] Referring to FIG. 3, the negative electrode (20) includes a negative electrode current collector (21); a negative electrode active material layer (23) disposed on the negative electrode current collector (21); and an electrodeposition induction layer (22) disposed between the negative electrode current collector (21) and the negative electrode active material layer (23). The electrodeposition induction layer (22) includes chromium (Cr), the negative electrode active material layer (23) includes lithium metal or a lithium alloy, and the electrodeposition induction layer (22) is disposed to extend to at least one side of the negative electrode current collector (21). The electrodeposition induction layer (22) completely covers the negative electrode current collector (21) and extends to the side surface of the negative electrode current collector (21). The electrodeposition induction layer (22) can completely cover the side surface of the negative electrode current collector (21). By extending the electrodeposition-inducing layer (22) to at least one side of the negative electrode current collector (21), the negative electrode current collector (21) can be more effectively protected, and the formation of lithium dendrites formed in the negative electrode active material layer (23) can be effectively suppressed.

[0064] Referring to FIG. 4, the negative electrode (20) includes a negative electrode current collector (21); and an electrodeposition-inducing layer (22) disposed on the negative electrode current collector (21), wherein the electrodeposition-inducing layer (22) includes chromium (Cr), and the electrodeposition-inducing layer (22) is disposed to extend to at least one side of the negative electrode current collector (21). The electrodeposition-inducing layer (22) is disposed to extend to the side of the negative electrode current collector (21). The electrodeposition-inducing layer (22) can completely cover the side of the negative electrode current collector (21). Since the electrodeposition-inducing layer (22) is disposed to extend to at least one side of the negative electrode current collector (21), uniform electrodeposition of a lithium metal layer deposited on the electrodeposition-inducing layer (22) can be induced and formation of lithium dendrites can be suppressed.

[0065] [Cathode: Cathode active material layer]

[0066] Referring to FIGS. 1 and 3, a negative electrode (20) for a lithium metal battery includes a negative electrode current collector (21); and a negative electrode active material layer (23) disposed on the negative electrode current collector (21), and includes an electrodeposition induction layer (22) disposed between the negative electrode current collector (21) and the negative electrode active material layer (23), wherein the negative electrode active material layer (23) may include lithium metal or a lithium alloy. Accordingly, the negative electrode active material layer (23) may be disposed between the electrodeposition induction layer (22) and an electrolyte layer (30) to be described later.

[0067] The negative electrode active material layer (23) may be, for example, a metal layer. The negative electrode active material layer (23) may include, for example, lithium metal or a lithium alloy. The negative electrode active material layer (23) may include, for example, lithium foil, lithium powder, plated lithium, a lithium alloy, an organic compound containing lithium, or a combination thereof. The negative electrode active material layer containing lithium foil may be, for example, a lithium metal layer. The negative electrode active material layer containing lithium powder may be introduced by coating a slurry containing lithium powder and a binder, etc., on a negative electrode current collector. The binder may be, for example, a fluorine-based binder such as polyvinylidene fluoride (PVDF). The negative electrode active material layer may not include a carbon-based negative electrode active material. Therefore, the negative electrode active material layer may be formed of a metal-based negative electrode active material. The negative electrode active material layer (23) may include, for example, non-fibrous lithium or non-acidic lithium. The negative electrode active material layer (23) may include, for example, plate-shaped lithium.

[0068] The thickness of the lithium foil may be, for example, 1 μm to 50 μm, 1 μm to 30 μm, or 10 μm to 30 μm, or 10 μm to 80 μm. When the lithium foil has a thickness in this range, the life characteristics of a lithium battery including an electrodeposition-inducing layer may be further improved. The particle size of the lithium powder may be, for example, 0.1 μm to 3 μm, 0.1 μm to 2 μm, or 0.1 μm to 2 μm. When the lithium powder has a thickness in this range, the life characteristics of a lithium battery including an electrodeposition-inducing layer may be further improved.

[0069] The thickness of the negative electrode active material layer (23) may be, for example, 0.1 µm to 100 µm, 0.1 µm to 80 µm, 1 µm to 80 µm, or 10 µm to 80 µm, but is not necessarily limited to this range and may be adjusted according to the shape, capacity, etc. of the required lithium battery.

[0070] Referring to FIGS. 2 and 4, the negative electrode (20) does not include a negative electrode active material layer (23) disposed on the negative electrode current collector (21) and the electrodeposition induction layer (22). The negative electrode (20) not including the negative electrode active material layer (23) may include a negative electrode active material layer (23) by plating lithium metal on the negative electrode current collector (21) and the electrodeposition induction layer (22) by charging after being introduced into a lithium battery together with the positive electrode and the electrolyte. The negative electrode active material layer may be a lithium plating layer (plated lithium layer). The negative electrode active material layer (23) may include, for example, non-fibrous lithium or non-acidic lithium. The negative electrode active material layer (23) may include, for example, plate-shaped lithium.

[0071] [Cathode: Negative current collector]

[0072] Referring to FIGS. 1 to 4, the negative electrode (20) for a lithium metal battery includes a negative electrode current collector (21).

[0073] The negative electrode current collector (21) includes, for example, a first metal substrate. The first metal substrate includes, as a main component, the first metal, or is made of the first metal. The first metal substrate includes, as a main component, the first metal, or is made of the first metal. The content of the first metal included in the first 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 first metal substrate. The first 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, but is not necessarily limited to, copper (Cu), nickel (Ni), stainless steel (SUS), iron (Fe), cobalt (Co), tantalum (Ta), tungsten (W), or any combination thereof, and any material that can be used as a current collector in the relevant technical field may be used. The first metal substrate may be composed of, for example, one of the above-described metals, or may be composed of an alloy of two or more metals. The first metal substrate is, for example, in the form of a sheet or foil. The thickness of the negative electrode current collector (21) 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 battery.

[0074] The negative electrode collector (21) may further include a coating layer (not shown) containing a second metal on the first metal substrate.

[0075] The negative electrode current collector (21) may include, for example, a first metal substrate; and a coating layer disposed on the first metal substrate and including a second metal. The second metal has a higher Mohs hardness than the first metal. That is, since the coating layer including the second metal is harder than the substrate including the first metal, deterioration of the first metal substrate can be prevented. The Mohs hardness of the material constituting the first 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 coating layer includes the second metal. The coating layer includes, for example, the second metal as a main component or is made of the second metal. The content of the second metal included in the coating layer 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 coating layer. The coating layer may be composed of, for example, a material that does not react with lithium, i.e., does not form an alloy and / or compound with lithium. 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 less, 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 excessively low, it may be difficult to suppress deterioration of the negative electrode current collector. If the Mohs hardness of the second metal is excessively 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 coating layer may be composed of, for example, one of the above-described metals, or may be composed of an alloy of two or more metals. The difference in Mohs hardness between the first metal included in the first metal substrate and the second metal included in the coating layer may be, for example, 2 or more, 2.5 or more, 3 or more, 3.5 or more, or 4 or more. Since the first metal and the second metal have such a difference in Mohs hardness, deterioration of the negative electrode current collector can be more effectively suppressed. The coating layer may have a single-layer structure or a multi-layer structure of two or more layers. The coating layer may have a two-layer structure including, for example, a first coating layer and a second coating layer. The coating layer may have a three-layer structure including, for example, a first coating layer, a second coating layer, and a third coating layer. The thickness of the coating layer may be, for example, 10 nm to 1 ㎛, 50 nm to 500 nm, 50 nm to 200 nm, or 50 nm to 150 nm. If the thickness of the coating layer is too thin, it may be difficult to suppress the uneven growth of the lithium-containing metal layer. As the thickness of the coating layer increases, the cycle characteristics of the lithium battery improve. However, if the thickness of the coating layer is too thick, the energy density of the lithium battery decreases and the formation of the coating layer may not be easy. The coating layer may be formed on the first metal substrate by, for example, a vacuum deposition method, a sputtering method, a plating method, etc., but is not necessarily limited to these methods, and any method capable of forming a coating layer in the relevant technical field may be used.

[0076] Although not shown in the drawing, the negative electrode current collector (21) may include, for example, a base film and a metal layer disposed on one or both sides of the base film. The base film may include, for example, a polymer. The polymer may be, for example, a thermoplastic polymer. The polymer may include, for example, polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polybutylene terephthalate (PBT), polyimide (PI), or a combination thereof. The polymer may be an insulating polymer. Since the base film includes an insulating thermoplastic polymer, when a short circuit occurs, the base film may soften or liquefy, thereby blocking battery operation and suppressing a rapid increase in current. The metal layer may include, for example, copper (Cu), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), or an alloy thereof. The metal layer may correspond to, for example, the first metal substrate. The metal layer may additionally include a coating layer including a second metal. The negative electrode current collector (21) may additionally include a metal piece and / or a lead tab. For more specific details on the base film, metal layer, metal chip, and lead tab of the negative electrode current collector (21), refer to the positive electrode current collector. By having such a structure, the negative electrode current collector (21) can reduce the weight of the negative electrode, thereby improving the energy density of the negative electrode and the lithium battery.

[0077] [Cathode: Protective layer]

[0078] Referring to FIGS. 1 to 4, the negative electrode (20) for a lithium metal battery may further include a protective layer (not shown) disposed between the negative electrode (20) for a lithium metal battery and an electrolyte layer (30) to be described later. The negative electrode active material layer (23) may be disposed between the protective layer and the negative electrode (20). The negative electrode active material layer (23) may be disposed between the electrodeposition-inducing layer (22) and the protective layer. By additionally including the protective layer, the negative electrode (20) protects the negative electrode active material layer (23), thereby suppressing additional reactions with the electrolyte layer (30) and further suppressing the generation and / or growth of lithium dendrites. The protective layer may be omitted.

[0079] [Cathode: Anode interlayer]

[0080] Referring to FIGS. 1 and 3, the negative electrode (20) for a lithium metal battery may optionally further include an anode interlayer (not shown) disposed between the electrodeposition induction layer (22) and the anode active material layer (23). Referring to FIGS. 2 and 4, the negative electrode (20) may optionally further include an anode interlayer (not shown) disposed between the electrodeposition induction layer (22) and the negative electrode current collector (21) or on the electrodeposition induction layer (22). By additionally including the anode interlayer in the negative electrode (20), the generation and / or growth of lithium dendrites in the negative electrode (20) can be more effectively suppressed. The anode interlayer may be omitted.

[0081] The negative electrode intermediate layer may include, for example, a negative electrode active material and a binder. The negative electrode active material is a negative electrode material that can be lithiated and delithiated. The negative electrode active material included in the negative electrode intermediate layer has, for example, a particle form. The negative electrode active material having a particle form has an average particle diameter, for example, 10 nm to 4 ㎛, 10 nm to 1 ㎛, 10 nm to 500 nm, 10 nm to 100 nm, or 20 nm to 80 nm. When the negative electrode active material has an average particle diameter in this range, reversible plating and / or dissolution of lithium may be facilitated during charge and discharge. The average particle diameter of the negative electrode active material is, for example, a median diameter (D50) measured using a laser particle size distribution analyzer.

[0082] The negative electrode active material included in the negative electrode intermediate layer may include, for example, at least one selected from a carbon-based negative electrode active material and a metal or metalloid negative electrode active material. The carbon-based negative electrode active material may be, for example, amorphous carbon. Examples of the carbon-based negative electrode active material include, but are not limited to, carbon black (CB), acetylene black (AB), furnace black (FB), ketjen black (KB), graphene, etc., and any material classified as amorphous carbon in the relevant technical field may be used. Amorphous carbon is carbon that has no crystallinity or very low crystallinity, and is distinguished from crystalline carbon or graphite-based carbon. The metal or metalloid negative electrode active material includes, but is not limited to, one or more selected from the group consisting of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn), and any metal or metalloid negative electrode active material that forms an alloy or compound with lithium in the relevant technical field may be used. For example, nickel (Ni) does not form an alloy with lithium, and therefore is not a metal negative electrode active material in the present specification. The negative electrode intermediate layer includes a type of negative electrode active material among these negative electrode active materials, or includes a mixture of a plurality of different negative electrode active materials. The negative electrode intermediate layer may include, for example, a mixture of amorphous carbon and one or more selected from the group consisting of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn). The mixing ratio of the mixture may be, for example, 10:1 to 1:2, 10:1 to 1:1, 7:1 to 1:1, 5:1 to 1:1, or 4:1 to 2:1 by weight.The negative electrode active material included in the negative electrode intermediate layer may include a mixture of first particles made of, for example, amorphous carbon and second particles made of a metal or a metalloid. The metal includes, for example, gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn). The content of the second particles is 8 to 60 wt%, 10 to 50 wt%, 15 to 40 wt%, or 20 to 30 wt% based on the total weight of the mixture. When the second particles have a content in this range, the cycle characteristics of, for example, a lithium battery are further improved.

[0083] The binder included in the negative electrode intermediate layer is, for example, styrene-butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, vinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, polymethyl methacrylate, etc., but is not necessarily limited thereto, and any binder used in the relevant technical field may be used. The binder may be composed of a single binder or a plurality of different binders. When the negative electrode intermediate layer does not include a binder, the negative electrode intermediate layer can be easily separated from the electrodeposition induction layer (22) or the negative electrode current collector (21). The content of the binder included in the negative electrode intermediate layer may be, for example, 1 to 20 wt% based on the total weight of the negative electrode intermediate layer.

[0084] The thickness of the negative electrode intermediate layer may be, for example, 1 ㎛ to 20 ㎛, 1 ㎛ to 15 ㎛, or 2 ㎛ to 10 ㎛, or 3 ㎛ to 7 ㎛. The thickness of the negative electrode intermediate layer may be, for example, 1% to 50%, 1% to 30%, 1% to 10%, or 1% to 5% of the thickness of the positive electrode active material layer. If the thickness of the negative electrode intermediate layer is too thin, lithium dendrites formed between the negative electrode intermediate layer and the negative electrode current collector may collapse the negative electrode intermediate layer, making it difficult to improve the cycle characteristics of the lithium battery. If the thickness of the negative electrode intermediate layer increases excessively, the energy density of a lithium battery employing the negative electrode (20) may decrease, and it may be difficult to improve the cycle characteristics. If the thickness of the negative electrode intermediate layer decreases, for example, the charge capacity of the negative electrode intermediate layer also decreases. The charge capacity of the negative electrode intermediate layer may be, for example, 0.1% to 50%, 1% to 30%, 1% to 10%, 1% to 5%, or 1% to 2% of the charge capacity. If the charge capacity of the negative electrode intermediate layer is too small, lithium dendrites formed between the negative electrode intermediate layer and the negative electrode current collector may collapse the negative electrode intermediate layer, making it difficult to improve the cycle characteristics of the lithium battery. If the charge capacity of the negative electrode intermediate layer increases excessively, the energy density of the lithium battery using the negative electrode (20) may decrease and it may be difficult to improve the cycle characteristics. The charge capacity of the positive electrode active material layer is obtained by multiplying the charge capacity density (mAh / g) of the positive electrode active material by the mass of the positive electrode active material in the positive electrode active material layer. 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 charge capacity of the positive electrode active material layer. The charge capacity of the negative electrode intermediate layer is also calculated in the same way. That is, the charge capacity of the negative electrode intermediate layer is obtained by multiplying the charge capacity density (mAh / g) of the negative electrode active material by the mass of the negative electrode active material in the negative electrode intermediate layer. When multiple types of negative electrode active materials are used, the charge capacity density Х mass value is calculated for each negative electrode active material, and the sum of these values ​​is the capacity of the negative electrode intermediate layer.Here, the charge capacity density of the positive and negative electrode materials is the capacity estimated using an all-solid-state half-cell using lithium metal as a counter electrode. The charge capacity of the positive electrode active material layer and the negative electrode intermediate layer is directly measured by measuring the charge capacity using the all-solid-state half-cell. The charge capacity density is obtained by dividing the measured charge capacity by the mass of each active material. Alternatively, the charge capacity of the positive electrode active material layer and the negative electrode intermediate layer may be the initial charge capacity measured at the first charge cycle.

[0085] [Lithium metal battery]

[0086] According to one embodiment, a lithium metal battery includes a positive electrode; the above-described negative electrode; and an electrolyte layer disposed between the positive electrode and the negative electrode, wherein the negative electrode includes lithium metal or a lithium alloy. By including the above-described negative electrode, the lithium metal battery can simultaneously provide improved capacity and excellent lifespan characteristics. The lithium metal battery may be, but is not limited to, a lithium primary battery, a lithium secondary battery, a lithium-sulfur battery, a lithium-air battery, etc., and any lithium metal battery used in the relevant technical field may be used.

[0087] Lithium metal batteries are manufactured by, for example, the following exemplary methods, but are not necessarily limited to these methods and are adjusted according to required conditions.

[0088] (cathode)

[0089] A negative electrode containing the lithium metal or lithium alloy described above is prepared.

[0090] (anode)

[0091] First, a positive electrode active material composition is prepared by mixing a positive electrode active material, a conductive agent, a binder, and a solvent. The prepared positive electrode active material composition is directly coated and dried on an aluminum current collector to produce a positive electrode plate having a positive electrode active material layer formed thereon. Alternatively, the positive electrode active material composition is cast on a separate support, and then the film obtained by peeling from the support is laminated on the aluminum current collector to produce a positive electrode plate having a positive electrode active material layer formed thereon.

[0092] The cathode active material is a lithium-containing metal oxide, and any one commonly used in the art can be used without limitation. For example, one or more types of composite oxides of lithium and a metal selected from cobalt, manganese, nickel, and combinations thereof can be used, and specific examples thereof include Li a A 1-b B b D2 (in the above formula, 0.90 ≤ a ≤ 1, and 0 ≤ b ≤ 0.5); Li a E 1-b B b O 2-c D c (In the above formula, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05); LiE 2-b B b O 4-c D c (In the above formula, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05); Li a Ni 1-b-c Co b B c D α (In the above equation, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α ≤ 2); Li a Ni 1-b-c Co b B c O 2-α F α (In the above equation, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2); Li aNi 1-b-c Co b B c O 2-α F2 (in the above formula, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2); Li a Ni 1-b-c Mn b B c D α (In the above equation, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α ≤ 2); Li a Ni 1-b-c Mn b B c O 2-α F α (In the above equation, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2); Li a Ni 1-b-c Mn b B c O 2-α F2 (in the above formula, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2); Li a Ni b E c G d O2 (in the above formula, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0.001 ≤ d ≤ 0.1); Li a Ni b Co c Mn d GeO2 (in the above formula, 0.90 ≤ a ≤ 1, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0 ≤ d ≤ 0.5, 0.001 ≤ e ≤ 0.1); Li a NiG b O2 (in the above formula, 0.90 ≤ a ≤ 1, 0.001 ≤ b ≤ 0.1); Li a CoG b O2 (in the above formula, 0.90 ≤ a ≤ 1, 0.001 ≤ b ≤ 0.1); Li a MnGb O2 (in the above formula, 0.90 ≤ a ≤ 1, 0.001 ≤ b ≤ 0.1); Li a Mn2G b O4 (wherein 0.90 ≤ a ≤ 1, 0.001 ≤ b ≤ 0.1); QO2; QS2; LiQS2; V2O5; LiV2O5; LiIO2; LiNiVO4; Li (3-f) J2(PO4)3(0 ≤ f ≤ 2); Li (3-f) A compound represented by any one of the chemical formulas Fe2(PO4)3(0 ≤ f ≤ 2); LiFePO4 can be used.

[0093] In the chemical formula representing the above-described compound, A is Ni, Co, Mn, or a combination thereof; B 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; E is Co, Mn, or a combination thereof; F is F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; Q is Ti, Mo, Mn, or a combination thereof; I is Cr, V, Fe, Sc, Y, or a combination thereof; J is V, Cr, Mn, Co, Ni, Cu, or a combination thereof. It is also possible to use a compound having a coating layer added to the surface of the above-described compound, or it is also possible to use a mixture of the above-described compound and the compound having a coating layer added. The coating layer added to the surface of the above-mentioned compound includes a coating element compound of, for example, an oxide, a hydroxide, an oxyhydroxide of the coating element, an oxycarbonate of the coating element, or a hydroxycarbonate of the coating element of the coating element. The compound forming the coating layer is amorphous or crystalline. The coating elements included in the coating layer are Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, or a mixture thereof. The method for forming the coating layer is selected within a range that does not adversely affect the physical properties of the positive electrode active material. The coating method includes, for example, spray coating and dipping. Since the specific coating method is well understood by those working in the relevant field, a detailed description thereof will be omitted.

[0094] The cathode active material is, for example, Li a Ni x Co y M z O 2-b A b(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, M은 망간(Mn), 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 조합), LiNi x Co y Mn z O2(0.8≤x≤0.95, 0≤y≤0.2, 0 <z≤0.2 및 x+y+z=1), LiNi x Co y Al z O2(0.8≤x≤0.95, 0≤y≤0.2, 0 <z≤0.2 및 x+y+z=1), LiNi x Co y Mn z Al w O2(0.8≤x≤0.95, 0≤y≤0.2, 0 <z≤0.2, 0<w≤0.2, 및 x+y+z+w=1), Li a Co x M y O 2-b A b (1.0≤a≤1.2, 0≤b≤0.2, 0.9≤x≤1, 0≤y≤0.1, and x+y=1, 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), Li a Ni x Mn y M' z O 2-b A b(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 조합), Li a M1 x M2 y PO 4-b X b (In the above chemical formula 7, 0.90≤a≤1.1, 0≤x≤0.9, 0≤y≤0.5, 0.9 <x+y<1.1, 0≤b≤2 이며, M1이 크롬(Cr), 망간(Mn), 철(Fe), 코발트(Co), 니켈(Ni), 구리(Cu), 지르코늄(Zr) 또는 이들의 조합이며, M2가 마그네슘(Mg), 칼슘(Ca), 스트론튬(Sr), 바륨(Ba), 티탄(Ti), 아연(Zn), 보론(B), 니오븀(Nb), 갈륨(Ga), 인듐(In), 몰리브덴(Mo), 텅스텐(W), 알루미늄(Al), 실리콘(Si), 크롬(Cr), 바나듐(V), 스칸듐(Sc), 이트륨(Y) 또는 이들의 조합이며, X가 O, F, S, P 또는 이들의 조합), Li a M3 z PO4 (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).

[0095] The conductive material may include, but is 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 relevant technical field may be used. Alternatively, the anode may not include a separate conductive material, for example.

[0096] As the binder, vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride, polyacrylonitrile, polymethyl methacrylate, polytetrafluoroethylene (PTFE), mixtures of the above-mentioned polymers, styrene butadiene rubber-based polymers, etc. are used, and as the solvent, N-methylpyrrolidone (NMP), acetone, water, etc. are used, but are not necessarily limited to these, and any solvent used in the relevant technical field may be used.

[0097] It is also possible to form pores inside the electrode plate by further adding a plasticizer or a pore forming agent to the positive electrode active material composition.

[0098] The contents of the cathode active material, conductive agent, binder, and solvent used 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, binder, and solvent may be omitted.

[0099] The binder content included in the positive electrode 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. The positive electrode active material content included in the positive electrode 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.

[0100] The positive electrode collector uses a plate or foil made of, for example, indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li), or an alloy thereof. The thickness of the positive electrode collector is, for example, 1 ㎛ to 100 ㎛, 1 ㎛ to 50 ㎛, 5 ㎛ to 25 ㎛, or 10 ㎛ to 20 ㎛.

[0101] The cathode 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, when a short circuit occurs, the base film may soften or liquefy, thereby blocking battery operation and suppressing a sudden increase in current. The metal layer may include, for example, indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), or an alloy thereof. The metal layer can act as an electrochemical fuse and cut off in case of overcurrent to prevent short circuits. 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. As the thickness of the metal layer decreases, the limit current and / or maximum current of the positive electrode current collector decreases, thereby improving the stability of the lithium battery in case of a short circuit. A lead tab can be added to the metal layer for external connection. The lead tab can be welded to the metal layer or the metal layer / base film laminate by ultrasonic welding, laser welding, spot welding, etc. During welding, the base film and / or the metal layer melt, so that the metal layer can be electrically connected to the lead tab. To strengthen the welding between the metal layer and the lead tab, a metal chip can be added between the metal layer and the lead tab.The metal piece may be a thin piece of the same material as the metal of the metal layer. The metal piece may be, for example, a metal foil, a metal mesh, etc. The metal piece may be, for example, aluminum foil, copper foil, SUS foil, etc. After the metal piece is placed on the metal layer, the lead tab may be welded to the metal piece / metal layer laminate or the metal piece / metal layer / base film laminate. During welding, the base film, the metal layer, and / or the metal piece may melt, so that the metal layer or the metal layer / metal piece laminate may be electrically connected to the lead tab. A metal chip and / or a lead tab may be added to a portion of the metal layer. The base film may have a thickness of, for example, 1 to 50 μm, 1.5 to 50 μm, 1.5 to 40 μm, or 1 to 30 μm. When the base film has a thickness in this range, the weight of the electrode assembly can be more effectively reduced. The melting point of the base film may be, for example, 100 to 300°C, 100 to 250°C or less, or 100 to 200°C. Since the base film has a melting point within this range, the base film can be melted and easily bonded to the lead tab during the welding process of the lead tab. To improve the adhesion between the base film and the metal layer, a surface treatment such as corona treatment may be performed on the base film. The thickness of the metal layer may be, for example, 0.01 to 3 μm, 0.1 to 3 μm, 0.1 to 2 μm, or 0.1 to μm. Since the metal layer has a thickness within this range, conductivity can be maintained while ensuring the stability of the electrode assembly. The thickness of the metal piece may be, for example, 2 to 10 μm, 2 to 7 μm, or 4 to 6 μm. Since the metal piece has a thickness within this range, the connection between the metal layer and the lead tab can be performed more easily. By having this structure as the cathode current collector, the weight of the cathode can be reduced, and as a result, the energy density of the cathode and lithium battery can be improved.

[0102] (Separator)

[0103] Next, a separator to be inserted between the positive and negative electrodes is prepared.

[0104] Any separator commonly used in lithium batteries can be used. For example, a separator with low resistance to ion migration and excellent electrolyte absorption capacity is used. The separator may be selected from glass fiber, polyester, Teflon, polyethylene, polypropylene, polytetrafluoroethylene (PTFE), or combinations thereof, and may be in the form of a nonwoven or woven fabric. For lithium-ion batteries, a rollable separator, such as polyethylene or polypropylene, is used, while for lithium-ion polymer batteries, a separator with excellent organic electrolyte absorption capacity is used.

[0105] The separator is manufactured by the following exemplary methods, but is not limited to these methods and may be adjusted according to required conditions.

[0106] First, a separator composition is prepared by mixing a polymer resin, a filler, and a solvent. The separator composition is directly coated and dried on the electrode to form a separator. Alternatively, the separator composition is cast on a support and dried, and then a separator film peeled from the support is laminated on the electrode to form a separator.

[0107] The polymer used in separator manufacturing is not particularly limited; any polymer used as a binder for electrode plates can be used. Examples include vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride (PVDF), polyacrylonitrile, polymethyl methacrylate, or mixtures thereof.

[0108] (electrolyte)

[0109] Next, an electrolyte is prepared. The electrolyte can be, for example, a liquid electrolyte, a solid electrolyte, a gel electrolyte, or a combination thereof. The electrolyte is, for example, an organic electrolyte. An organic electrolyte is prepared by dissolving a lithium salt in an organic solvent.

[0110] Any organic solvent used in the relevant technical field may be used. Examples of the organic solvent include propylene carbonate, ethylene carbonate, fluoroethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl isopropyl carbonate, dipropyl carbonate, dibutyl carbonate, benzonitrile, acetonitrile, tetrahydrofuran, 2-methyltetrahydrofuran, γ-butyrolactone, dioxolane, 4-methyldioxolane, N,N-dimethylformamide, dimethylacetamide, dimethyl sulfoxide, dioxane, 1,2-dimethoxyethane, sulfolane, dichloroethane, chlorobenzene, nitrobenzene, diethylene glycol, dimethyl ether, or mixtures thereof.

[0111] Lithium salts are all possible if they are used as lithium salts in the relevant technical field. Lithium salts include, 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)(1≤x≤20, 1≤y≤20), LiCl, LiI or a mixture thereof. The concentration of the lithium salt is, for example, 0.1 M to 5.0 M.

[0112] The solid electrolyte is, for example, an oxide-based solid electrolyte, a sulfide-based solid electrolyte, a polymer solid electrolyte, or a combination thereof.

[0113] Solid electrolytes are, for example, oxide-based solid electrolytes. Oxide-based solid electrolytes are Li 1+x+y Al xTi 2-x Si y P 3-y O 12 (0 <x<2, 0≤y<3), BaTiO3, Pb(Zr,Ti)O3(PZT), Pb 1-x La x Zr 1-y Ti y O3(PLZT)(O≤x<1, O≤y<1), PB(Mg3Nb 2 / 3 )O3-PbTiO3(PMN-PT), HfO2, SrTiO3, SnO2, CeO2, Na2O, MgO, NiO, CaO, BaO, ZnO, ZrO2, Y2O3, Al2O3, TiO2, SiO2, Li3PO4, Li x Ti y (PO4)3(0 <x<2, 0<y<3), Li x Al y Ti z (PO4)3(0 <x<2, 0<y<1, 0<z<3), Li 1+x+y (Al, Ga) x (Ti, Ge) 2-x Si y P 3-y O 12 (0≤x≤1 0≤y≤1), Li x La y TiO3(0 <x<2, 0<y<3), Li2O, LiOH, Li2CO3, LiAlO2, Li2O-Al2O3-SiO2-P2O5-TiO2-GeO2, Li 3+x La3M2O 12 (M = Te, Nb, or Zr, x is an integer from 1 to 10) is one or more selected from. The solid electrolyte is manufactured by a sintering method, etc. For example, the oxide-based solid electrolyte is Li7La3Zr2O 12 (LLZO) and Li 3+x La3Zr 2-a M a O 12 A garnet-type solid electrolyte selected from (M doped LLZO, M=Ga, W, Nb, Ta, or Al, x is an integer from 1 to 10).

[0114] The sulfide-based solid electrolyte may include, for example, lithium sulfide, silicon sulfide, phosphorus sulfide, boron sulfide, or a combination thereof. The sulfide-based solid electrolyte particles may include Li2S, P2S5, SiS2, GeS2, B2S3, or a combination thereof. The sulfide-based solid electrolyte particles may be Li2S or P2S5. Sulfide-based solid electrolyte particles are known to have high lithium ion conductivity compared to other inorganic compounds. For example, the sulfide-based solid electrolyte includes Li2S and P2S5. When the sulfide solid electrolyte material constituting the sulfide-based solid electrolyte includes Li2S-P2S5, the mixing molar ratio of Li2S to P2S5 may be, for example, in a range of about 50:50 to about 90:10. In addition, Li3PO4, halogen, halogen compound, Li 2+2x Zn 1-x GeO4("LISICON", 0≤x<1), Li 3+y PO 4-x N x( "LIPON" 0 <x<4, 0<y<3), Li 3.25 Ge 0.25 P 0.75 S4("Thio-LISICON"), Li2O-Al2O3-TiO2-P2O 5( An inorganic solid electrolyte prepared by adding "LATP") etc. to an inorganic solid electrolyte of Li2S-P2S5, SiS2, GeS2, B2S3, or a combination thereof can be used as a sulfide solid electrolyte. Non-limiting examples of sulfide solid electrolyte materials include Li2S-P2S5; Li2S-P2S5-LiX (X=halogen element); Li2S-P2S5-Li2O; Li2S-P2S5-Li2O-LiI; Li2S-SiS2; Li2S-SiS2-LiI; Li2S-SiS2-LiBr; Li2S-SiS2-LiCl; Li2S-SiS2-B2S3-LiI; Li2S-SiS2-P2S5-LiI; Li2S-B2S3; Li2S -P2S5-Z m S n(0 <m<10, 0<n<10, Z=Ge, Zn 또는 Ga); Li2S-GeS2; Li2S-SiS2-Li3PO4; 및 Li2S-SiS2-Li p FOR q (0 <p<10, 0<q<10, M=P, Si, Ge, B, Al, Ga 또는 In)을 포함한다. 이와 관련하여, 황화물계 고체전해질 재료는 황화물계 고체전해질 물질의 원료 시작 물질(예를 들면, Li2S, P2S5, 등)을 용융 담금질법(melt quenching method), 기계적 밀링법 등에 의해 처리함으로써 제조될 수 있다. 또한, 소성(calcinations) 공정이 상기 처리 후에 수행될 수 있다. 황화물계 고체전해질은 비정질이거나, 결정질이거나, 이들이 혼합된 상태일 수 있다.

[0115] 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, for example, be a polymer electrolyte that is solid at 25°C and 1 atm. The polymer solid electrolyte may, for example, not 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.

[0116] A gel electrolyte is, for example, a polymer gel electrolyte. A gel electrolyte can have a gel state without containing a polymer, for example.

[0117] 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-, BF4-, 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.

[0118] (lithium metal battery)

[0119] Referring to FIG. 5, a lithium metal battery (1) according to one embodiment includes a positive electrode (3), the aforementioned negative electrode (2), and a separator (4). The positive electrode (3), the negative electrode (2), and the separator (4) are wound or folded to form a battery structure (7). The formed battery structure (7) is accommodated in a battery case (5). An organic electrolyte is injected into the battery case (5) and sealed with a cap assembly (6), thereby completing the lithium metal battery (1). The battery case (5) is cylindrical, but is not necessarily limited to this shape, and may be, for example, square, thin-film, etc.

[0120] Referring to FIG. 6, a lithium metal battery (1) according to one embodiment includes a positive electrode (3), the aforementioned negative electrode (2), and a separator (4). A separator (4) is disposed between the positive electrode (3) and the negative electrode (2), and the positive electrode (3), the negative electrode (2), and the separator (4) are wound or folded to form a battery structure (7). The formed battery structure (7) is accommodated in a battery case (5). An electrode tab (8) that serves as an electrical path for guiding the current formed in the battery structure (7) to the outside may be included. An organic electrolyte is injected into the battery case (5) and sealed to complete the lithium battery (1). The battery case (5) is not necessarily limited to a square shape, but may be, for example, a cylindrical shape, a thin film shape, etc.

[0121] Referring to FIG. 7, a lithium metal battery (1) according to one embodiment includes a positive electrode (3), the aforementioned negative electrode (2), and a separator (4). A separator (4) is disposed between the positive electrode (3) and the negative electrode (2) to form a battery structure. The battery structure (7) is stacked in a bi-cell structure and then accommodated in a battery case (5). An electrode tab (8) that serves as an electrical path for guiding the current formed in the battery structure (7) to the outside may be included. An organic electrolyte is injected into the battery case (5) and sealed to complete the lithium metal battery (1). The battery case (5) is not necessarily limited to a square shape, but may be, for example, a cylindrical shape, a thin film shape, etc.

[0122] A pouch-type lithium metal battery corresponds to the lithium metal batteries of FIGS. 5 to 7, each of which uses a pouch as a battery case. The pouch-type lithium metal battery includes one or more battery structures. A separator is disposed between a positive electrode and a negative electrode to form a battery structure. The battery structures are laminated in a bi-cell structure, then impregnated with an organic electrolyte, and accommodated and sealed in a pouch to complete the pouch-type lithium metal battery. For example, although not shown in the drawings, the above-described positive electrode, negative electrode, and separator may be simply laminated and accommodated in a pouch in the form of an electrode assembly, or may be wound or folded into a jelly-roll-shaped electrode assembly and then accommodated in a pouch. Subsequently, an organic electrolyte is injected into the pouch and sealed to complete the lithium battery.

[0123] The lithium metal battery of the present disclosure has excellent discharge capacity and cycle life characteristics, as well as high energy density, and is therefore used in, for example, electric vehicles (EVs). For example, it is used in hybrid vehicles such as plug-in hybrid electric vehicles (PHEVs). It is also used in applications requiring large amounts of power storage, such as electric bicycles and power tools.

[0124] Lithium metal batteries are stacked in multiple layers to form a battery module, and the multiple battery modules form a battery pack. Such a battery pack can be used in any device requiring high capacity and high output. For example, it can be used in laptops, smartphones, electric vehicles, etc. The battery module includes, for example, multiple batteries and a frame that holds them. The battery pack includes, for example, multiple battery modules and a bus bar that connects them. The battery module and / or the battery pack may further include a cooling device. The multiple battery packs are controlled by a battery management system. The battery management system includes a battery pack and a battery control device connected to the battery pack.

[0125] A lithium metal battery containing a solid electrolyte is described in more detail below.

[0126] (all-solid-state lithium metal battery)

[0127] The lithium metal battery may be, for example, an all-solid-state lithium metal battery including a solid electrolyte. By including the above-described negative electrode, the all-solid-state lithium metal battery can simultaneously provide improved capacity and excellent lifespan characteristics.

[0128] All-solid-state lithium metal batteries are manufactured, for example, by the following exemplary methods, but are not necessarily limited to these methods and are adjusted according to required conditions.

[0129] Referring to FIGS. 8 and 9, the all-solid-state lithium metal battery (1) includes a positive electrode (10); the aforementioned negative electrode (20); and a solid electrolyte layer (30) disposed between the positive electrode (10) and the negative electrode (20). The solid electrolyte layer (30) includes, for example, an inorganic solid electrolyte. The solid electrolyte layer (30) includes, for example, a sulfide-based solid electrolyte or an oxide-based solid electrolyte.

[0130] (cathode)

[0131] A negative electrode containing the lithium metal or lithium alloy described above is prepared.

[0132] (anode)

[0133] Referring to FIGS. 8 to 9, the positive electrode (10) includes a positive electrode current collector (11) and a positive electrode active material layer (12) disposed on the positive electrode current collector. The positive electrode active material layer (12) includes a positive electrode active material. The positive electrode active material refers to the lithium battery section described above.

[0134] The positive electrode active material layer (12) may further include a solid electrolyte in addition to the positive electrode active material. The solid electrolyte included in the positive electrode (10) may be the same as or different from the solid electrolyte included in the solid electrolyte layer (30). For details on the solid electrolyte included in the positive electrode (10), refer to the solid electrolyte layer (30) section. The solid electrolyte used in the positive electrode active material layer (12) may have a smaller D50 average particle size than the solid electrolyte used in the solid electrolyte layer (30). For example, the D50 average particle size of the solid electrolyte used in the positive electrode active material layer (12) may be 90% or less, 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, or 20% or less of the D50 average particle size of the solid electrolyte used in the solid electrolyte layer (30). The average D50 particle size of the solid electrolyte used in the positive electrode active material layer (12) may be, for example, 0.1 µm to 2 µm, 0.2 µm to 1.5 µm, or 0.3 µm to 1.0 µm. The content of the solid electrolyte included in the positive electrode active material layer (12) may be 1 to 15 wt%, 5 to 15 wt%, or 8.0 to 12.0 wt% of the total weight of the positive electrode active material layer (12).

[0135] The positive electrode active material layer (12) may include a binder. The binder may be, for example, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, etc., but is not necessarily limited thereto and may be any binder that can be used in the relevant technical field. The content of the binder included in the positive electrode active material layer (12) may be, for example, 0.1 to 5 wt%, 0.5 to 3 wt%, or 1.0 to 2.0 wt% of the total weight of the positive electrode active material layer (12).

[0136] The cathode active material layer (12) may include a conductive material. The conductive material may be, for example, a carbon-based conductive material or a metal-based conductive material. The conductive material is not necessarily limited to graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon tube, metal powder, etc., and any conductive material that can be used as a conductive material in the relevant technical field may be used. The content of the conductive material included in the cathode active material layer (12) may be, for example, 0.1 to 10 wt%, 0.5 to 5 wt%, or 1.0 to 4.0 wt% of the total weight of the cathode active material layer (12). In addition to the above-described cathode active material, solid electrolyte, binder, and conductive material, the cathode active material layer (12) may further include additives such as fillers, coating agents, dispersants, and ion conductive aids.

[0137] The positive electrode current collector (11) may be, for example, a plate or foil made of aluminum (Al), indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), germanium (Ge), lithium (Li), or an alloy thereof. The positive electrode current collector (11) may be omitted. The positive electrode current collector (11) may further include a carbon layer disposed on one or both sides of the metal substrate. By additionally disposing the carbon layer on the metal substrate, the metal of the metal substrate is prevented from being corroded by the solid electrolyte included in the positive electrode layer, and the interface resistance between the positive electrode active material layer (12) and the positive electrode current collector (11) may be reduced. The thickness of the carbon layer may be, for example, 1 µm to 5 µm, 1 µm to 4 µm, or 1 µm to 3 µm. If the carbon layer is too thin, it may be difficult to completely block contact between the metal substrate and the solid electrolyte. If the carbon layer is too thick, the energy density of the all-solid-state secondary battery may decrease. The carbon layer may include amorphous carbon, crystalline carbon, etc. The thickness of the positive electrode current collector (11) including the metal substrate and optionally the carbon layer may be, for example, 10 ㎛ to 50 ㎛, 10 ㎛ to 40 ㎛, or 10 ㎛ to 30 ㎛, but is not necessarily limited to this range, and may be selected depending on the characteristics of the all-solid-state lithium battery required.

[0138] Although not shown in the drawing, the positive electrode (10) may further include a positive electrode current collector (11), a positive electrode active material layer (12) disposed on the positive electrode current collector, and an inactive member disposed on one side of the positive electrode active material layer. The area of ​​the positive electrode active material layer (12) may be smaller than the area of ​​the solid electrolyte layer (30) in contact with the positive electrode active material layer (12). The inactive member may be disposed to surround the side of the positive electrode active material layer (12) to correct an area error between the positive electrode active material layer (12) and the solid electrolyte layer (30). The inactive member is a member that does not contain an electrochemically active material, for example, an electrode active material. The electrode active material is a material that absorbs / releases lithium. The inactive member is a member made of a material other than the electrode active material and used in the relevant technical field. The inert member surrounds the side surface of the positive electrode active material layer (12) and can be in contact with the solid electrolyte layer (30). Since the inert member surrounds the side surface of the positive electrode active material layer (12) 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 does not come into contact with the positive electrode active material layer (12) can be effectively suppressed. Since the area of ​​the inert member compensates for the difference between the area of ​​the positive electrode active material layer (12) and the area of ​​the solid electrolyte layer (30), cracks in the solid electrolyte layer (30) that occur due to a pressure difference during the pressing process can be effectively suppressed. The inert member can be disposed between the positive electrode current collector (11) and the solid electrolyte layer (30) that face each other. The inert member can serve as a filler that fills the space between the positive electrode current collector (11) and the solid electrolyte layer (30) that face each other. The inert member may include at least one selected from a lithium ion insulator and a lithium ion conductor. The inert member may be an electronic insulator. That is, the inert member may not be an electronic conductor.The inert member may be an organic material, an inorganic material, or an organic-inorganic composite material. The organic material may be, for example, a polymer. The inorganic material may be, for example, a ceramic such as a metal oxide. The organic-inorganic composite material may be a composite of a polymer and a metal oxide. The inert member may include, for example, at least one selected from the group consisting of an insulating polymer, an ion-conducting polymer, an insulating inorganic material, an oxide-based solid electrolyte, and a sulfide-based solid electrolyte. The inert member may be, for example, an olefin-based polymer such as polypropylene (PP) or polyethylene (PE). The inert member (40) may be, for example, a gasket. The thickness of the inert member may be the same as or similar to the thickness of the positive electrode active material layer (12).

[0139] (solid electrolyte layer)

[0140] Referring to FIGS. 8 to 9, a solid electrolyte layer (30) is disposed between the positive electrode (10) and the negative electrode (20) and includes, for example, a sulfide-based solid electrolyte.

[0141] Sulfide-based solid electrolytes include, for example, Li2S-P2S5, Li2S-P2S5-LiX, where X is a halogen element, Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z m S n , m, n are positive numbers, Z is one of Ge, Zn or Ga, Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q , p, q are positive numbers, M is one of P, Si, Ge, B, Al, Ga In, Li 7-x PS 6-x Cl x , 0≤x≤2, Li 7-x PS 6-xBr x , 0≤x≤2, and Li 7-x PS 6-x I x , may include at least one selected from 0≤x≤2. The sulfide-based solid electrolyte is manufactured by treating starting materials such as Li2S and P2S5 by a melting rapid cooling method or a mechanical milling method. In addition, heat treatment may be performed after the treatment. The solid electrolyte may be amorphous, crystalline, or a mixture thereof. In addition, the solid electrolyte may be, for example, one containing sulfur (S), phosphorus (P), and lithium (Li) as constituent elements among the above-described sulfide-based solid electrolyte materials. For example, the solid electrolyte may be a material containing Li2S-P2S5. When using a sulfide-based solid electrolyte material containing Li2S-P2S5 to form the solid electrolyte, the mixing molar ratio of Li2S and P2S5 is, for example, in the range of Li2S: P2S5= 50:50 to 90:10.

[0142] The sulfide-based solid electrolyte may include, for example, an argyrodite type solid electrolyte represented by the following chemical formula 1:

[0143] <Chemical Formula 1>

[0144] Li + 12-n-x A n+ X 2- 6-x Y - x

[0145] In the above formula, A is P, As, Ge, Ga, Sb, Si, Sn, Al, In, Ti, V, Nb or Ta, X is S, Se or Te, Y is Cl, Br, I, F, CN, OCN, SCN or N3, and 1≤n≤5, 0≤x≤2. The sulfide-based solid electrolyte is, for example, Li 7-x PS 6-x Cl x, 0≤x≤2, Li 7-x PS 6-x Br x , 0≤x≤2, and Li 7-x PS 6-x I x , 0≤x≤2. The sulfide-based solid electrolyte may be, for example, an argyrodite-type compound including at least one selected from Li6PS5Cl, Li6PS5Br, and Li6PS5I. The density of the argyrodite-type solid electrolyte may be 1.5 to 2.0 g / cc. Since the argyrodite-type solid electrolyte has a density of 1.5 g / cc or more, the internal resistance of the all-solid-state secondary battery is reduced, and penetration of the solid electrolyte layer by Li can be effectively suppressed.

[0146] The elastic modulus, i.e., Young's modulus, of the sulfide-based solid electrolyte may be, for example, 35 GPa or less, 30 GPa or less, 27 GPa or less, 25 GPa or less, or 23 GPa or less. The elastic modulus, i.e., Young's modulus, of the sulfide-based solid electrolyte may be, for example, 10 to 35 GPa, 10 to 30 GPa, 10 to 27 GPa, 10 to 25 GPa, or 10 to 23 GPa. Since the sulfide-based solid electrolyte has an elastic modulus in this range, the temperature and / or pressure required for sintering, etc. is reduced, and thus sintering of the solid electrolyte can be performed more easily.

[0147] The average D50 particle size of the solid electrolyte used in the solid electrolyte layer (30) may be, for example, 1 μm to 10 μm, 1.5 μm to 7 μm, or 2 μm to 5 uμm.

[0148] The content of the sulfide-based solid electrolyte included in the solid electrolyte layer (30) may be, for example, 97 to 100 wt%, 98 to 99.9 wt%, or 98.5 to 99.0 wt% of the total weight of the solid electrolyte layer (30).

[0149] The solid electrolyte layer (30) may further include, for example, a binder. The binder included in the solid electrolyte layers (30, 30a, 30b) may be, for example, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, etc., but is not limited thereto, and any binder used in the relevant technical field may be used. The binder of the solid electrolyte layer (30) may be the same as or different from the binder included in the positive electrode active material layer (12) and the negative electrode active material layer (23).

[0150] The content of the binder included in the solid electrolyte layer (30) may be, for example, 0.1 to 3 wt%, 0.5 to 2 wt%, or 1.0 to 2.0 wt% of the total weight of the solid electrolyte layer (30).

[0151] Referring to FIGS. 8 and 9, the all-solid-state lithium metal battery (1) includes a solid electrolyte layer (30), a positive electrode layer (10) disposed on one surface of the solid electrolyte layer (30), and a negative electrode layer (20) disposed on the other surface of the solid electrolyte layer (30). The positive electrode layer (30) includes a positive electrode active material layer (12) in contact with the solid electrolyte layer (30) and a positive electrode current collector (11) in contact with the positive electrode active material layer (12), and the negative electrode layer (20) includes a deposition-inducing layer (22) in contact with the solid electrolyte layer (30) and a negative electrode current collector (21) in contact with the deposition-inducing layer (22). For example, an all-solid-state lithium metal battery (1) is completed by sequentially stacking a positive electrode active material layer (12) and an electrodeposition-inducing layer (22) on both sides of a solid electrolyte layer (30), and then stacking a positive electrode current collector (11) and an anode current collector (21) on the positive electrode active material layer (12) and the electrodeposition-inducing layer (22), respectively, to form an all-solid-state lithium metal battery (30). Alternatively, an all-solid-state lithium metal battery (1) is completed by sequentially stacking a positive electrode active material layer (12), a solid electrolyte layer (30), and a positive electrode current collector (11) on an anode current collector (21).

[0152] The overpotential during the initial charge of a lithium metal battery may be lower than that of a lithium metal battery without an electrodeposition-inducing layer. The overpotential during the initial charge of a lithium metal battery may be 0.01 V or less. The very low overpotential during the initial charge of a lithium metal battery may be due to the uniform electrodeposition of lithium metal by the electrodeposition-inducing layer, thereby suppressing the formation of lithium dendrites. Therefore, a lithium metal battery with an electrodeposition-inducing layer may exhibit significantly improved charge and cycle characteristics.

[0153] [Method for Manufacturing Lithium Metal Battery]

[0154] A method for manufacturing a lithium metal battery according to another embodiment includes the steps of providing a negative electrode current collector; and the steps of providing an electrodeposition-inducing layer on the negative electrode current collector to provide a negative electrode; and the steps of providing a positive electrode on the negative electrode and providing an electrolyte layer between the negative electrode and the positive electrode, wherein the electrodeposition-inducing layer may include chromium (Cr).

[0155] First, a negative electrode current collector is provided. The negative electrode current collector refers to the negative electrode portion described above. For example, copper foil is provided as the negative electrode current collector. Next, an electrodeposition induction layer is provided on the negative electrode current collector to provide the negative electrode.

[0156] The electrodeposition-inducing layer may be provided, for example, by providing chromium (Cr) on the negative electrode current collector. For example, chromium (Cr) may be provided by coating and / or drying the negative electrode current collector. The step of providing the electrodeposition-inducing layer may include the step of providing composite particles, which are copper particles coated with chromium (Cr), on the negative electrode current collector. The step of providing the electrodeposition-inducing layer may include the step of providing the composite particles, for example, through a roll press method or a spray method.

[0157] The step of providing an electrodeposition-inducing layer may include a step of treating a negative electrode current collector with a chromate solution. The step of providing an electrodeposition-inducing layer may include, for example, preparing a chromate solution or a dichromate solution by mixing chromate, dichromate, chromic acid, a chromate salt compound, or a combination thereof with a solvent, and then treating the negative electrode current collector with the chromate or dichromate solution. The step of providing an electrodeposition-inducing layer may include, for example, a step of contacting the negative electrode current collector with the chromate solution or dichromate solution. That is, after preparing a chromate solution mixture, the mixture may be brought into contact with, coated, and dried on the negative electrode current collector, thereby providing an electrodeposition-inducing layer. The mixture may include, for example, chromate and a solvent. The mixture may include, for example, chromate, dichromate, and a solvent.

[0158] The solvent may be water, an organic solvent, or any combination thereof. The solvent may be, for example, water or NMP, but is not necessarily limited thereto, and any solvent used in the art may be used.

[0159] The coating method can be, for example, coating using a doctor blade, roll press method, electroplating method, or spraying method.

[0160] 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.

[0161] Example 1: Cu-based / chromium (Cr)-containing electrodeposition-induced layer cathode

[0162] (Cathode manufacturing)

[0163] The cathode was formed to have a structure in which a chromate electrodeposition induction layer having a thickness of 1 ㎛ was coated on a copper current collector having a thickness of 10 ㎛.

[0164] (Polar electrode manufacturing)

[0165] LiCoO2 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 having a weight ratio of active material: carbon conductive material: binder = 90:5:5.

[0166] 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.

[0167] (Manufacturing of coin cells)

[0168] A polypropylene separator (ES1608) was placed between the positive and negative electrodes manufactured above, and an electrolyte was injected to manufacture a coin cell.

[0169] A solution containing 0.6 M lithium difluoro(oxalate)borate (LiDFOB) and 0.6 M lithium tetrafluoroborate (LiBF4) dissolved in fluoroethylene carbonate (FEC) + diethyl carbonate (DEC) (1:2 volume ratio) was used as an electrolyte.

[0170] Example 2: Cu-based / chromium (Cr)-containing electrodeposition-induced layer cathode

[0171] A negative electrode and coin cell were manufactured in the same manner as in Example 1, except that the negative electrode was manufactured to have a structure in which a 4 ㎛ thick electrodeposition induction layer was coated on a 10 ㎛ thick copper current collector.

[0172] Comparative Example 1: Cu-based cathode

[0173] A negative electrode and a coin cell were manufactured in the same manner as in Example 1, except that the electrodeposition induction layer was not included.

[0174] Comparative Example 2: Cu-based / tin-containing electrodeposition-induced layer cathode

[0175] A negative electrode and a coin cell were manufactured in the same manner as in Example 1, except that a copper current collector having a structure coated with a 1 μm electrodeposition-inducing layer containing tin (Sn) was used.

[0176] Comparative Example 3: Cu-based / aluminum-containing electrodeposition-induced layer cathode

[0177] A negative electrode and a coin cell were manufactured in the same manner as in Example 1, except that an aluminum (Al) foil was prepared and a negative electrode was prepared by rolling the aluminum foil on a copper current collector to form an electrodeposition-inducing layer having a thickness of 2 μm.

[0178] Evaluation Example 1: 1st Charge Curve Evaluation

[0179] The lithium batteries manufactured in Example 1 and Comparative Example 1 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 was performed at a current of 0.05 C rate while maintaining 4.2 V in constant voltage mode. The charging curves are shown in Fig. 10, and 1 st The cross-section of the cathode after charging is shown in Figs. 11 and 12.

[0180] As shown in Fig. 10, it was confirmed that the lithium battery of Example 1 had a reduced overpotential compared to the lithium battery of Comparative Example 1.

[0181] This overpotential reduction is believed to be due to the fact that the electrodeposition-inducing layer containing chromium (Cr) suppressed the formation of lithium dendrites and induced uniform electrodeposition of lithium, and as shown in FIGS. 11 and 12, Example 1 st After charging, uniform and wide lithium deposition is confirmed, but Comparative Example 1 is 1 st After charging, it can be seen that lithium dendrites are formed.

[0182] Evaluation Example 2: Charge / Discharge Test

[0183] The lithium batteries manufactured in Examples 1 to 3 and Comparative Examples 1 to 3 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 was achieved 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 2.8 V (vs. Li) during discharge (formation cycle).

[0184] This cycle is 180 th The cycle was repeated under the same conditions. However, Comparative Example 3 was 120 th The cycle was repeated under the same conditions.

[0185] In all charge / discharge cycles, a 10-minute pause was provided after each charge / discharge cycle. Some of the results of the room-temperature charge / discharge experiments are shown in Table 1 and Figure 13. The capacity retention rate is defined by the following mathematical equation (1).

[0186] <Mathematical Formula 1>

[0187] Capacity retention rate [%] = [180 th Discharge capacity in cycles / 1 st Discharge capacity in cycles] Х 100

[0188] Electrodeposition-induced layer composition Electrodeposition-induced layer thickness (㎛) Capacity retention rate [%] (180 th Cycle) Example 1 Chromium hydroxide 174 Example 2 Chromium hydroxide 478 Comparative Example 1--66 Comparative Example 2 Tin 162 Comparative Example 3 Aluminum 238 (120 th cycle)

[0189] As shown in Table 1 and Fig. 13, the lithium batteries of Examples 1 and 2 had improved capacity retention rates compared to the lithium batteries of Comparative Examples 1 to 3.

[0190] This improved capacity retention was attributed to the fact that the electrodeposition-inducing layer containing chromium (Cr) suppressed the formation of lithium dendrites and induced uniform electrodeposition of lithium.

[0191] The lithium battery of Comparative Example 1, which did not include an electrodeposition induction layer, showed poor life characteristics.

[0192] The lithium batteries of Comparative Examples 2 and 3 exhibited poor life characteristics. This was attributed to the fact that in the lithium batteries of Comparative Examples 2 and 3, the electrodeposition-inducing layer not containing chromium (Cr) failed to suppress the formation of lithium dendrites and failed to induce uniform electrodeposition of lithium.

[0193] 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.

[0194] [Explanation of symbols]

[0195] 1 lithium battery 2, 20 cathode

[0196] 3, 10 positive electrode 4 separator

[0197] 5 Battery case 6 Cap assembly

[0198] 7 Battery structure 8 Electrode tab

[0199] 11. Cathode current collector 12. Cathode active material layer

[0200] 21 Negative current collector 22 Electrodeposition induction layer

[0201] 23 Negative active material layer 30 Solid electrolyte layer

Claims

1. It comprises an anode; a cathode; and an electrolyte layer disposed between the anode and the cathode, The above cathode negative current collector; and It includes an electrodeposition induction layer disposed on the above negative electrode collector; A lithium metal battery, wherein the electrodeposition-inducing layer contains chromium (Cr).

2. In the first paragraph, the electrodeposition-inducing layer includes chromium hydroxide, chromium oxide, or a combination thereof, The above electrodeposition-induced layer is derived from chromate, dichromate, and any combination thereof, or The above electrodeposition-inducing layer includes composite particles, A lithium metal battery comprising a core, a composite particle, and a shell disposed on the core, wherein the core comprises the same metal as the negative electrode current collector, and the shell comprises chromium.

3. A lithium metal battery in the second paragraph, wherein the particle size of the composite particles is 0.5 ㎛ to 10 ㎛.

4. In the first paragraph, the electrodeposition-inducing layer includes Cr(OH)3, Cr2O3, CrO3 or a combination thereof, A lithium metal battery, wherein the content of the chromium (Cr) is 1 to 10 wt% of the total weight of the electrodeposition-inducing layer.

5. A lithium metal battery, wherein the ratio of the thickness of the electrodeposition-inducing layer to the thickness of the negative electrode current collector in the first paragraph is 0.01 to 0.

45.

6. In the first paragraph, the chromium deposition amount of the electrodeposition-inducing layer is 1.0 mg / m 2 100 mg / m 2 In, lithium metal battery.

7. A lithium metal battery according to claim 1, wherein the thickness of the electrodeposition-inducing layer is 0.01 ㎛ to 5 ㎛.

8. A lithium metal battery in which the electrodeposition-inducing layer is free of polymer in the first paragraph.

9. In the first paragraph, the overpotential at the time of initial charging of the lithium metal battery is smaller than the overpotential at the time of initial charging of the lithium metal battery without the electrodeposition-inducing layer, A lithium metal battery having an overvoltage of 0.01 V or less during initial charging of the lithium metal battery.

10. A lithium metal battery in the first paragraph, wherein the negative electrode collector comprises copper (Cu), nickel (Ni), stainless steel (SUS), iron (Fe), cobalt (Co), tantalum (Ta), tungsten (W), or any combination thereof.

11. In the first paragraph, a negative electrode active material layer is further included between the electrolyte layer and the negative electrode, The above negative electrode active material layer is a metal layer, and the metal layer includes lithium metal or a lithium alloy, or A lithium metal battery, wherein the negative electrode active material layer comprises lithium foil, lithium powder, plated lithium, a lithium alloy, an organic compound containing lithium, or a combination thereof.

12. In the 11th paragraph, the negative electrode active material layer includes non-fibrous lithium or non-acidic lithium, A lithium metal battery, wherein the negative electrode active material layer comprises plate-shaped lithium.

13. A lithium metal battery according to claim 11, wherein the thickness of the negative electrode active material layer is 0.1 ㎛ to 100 ㎛.

14. In the first paragraph, a protective layer is further included between the cathode and the electrolyte layer, A lithium metal battery further comprising a negative electrode active material layer disposed between the protective layer and the negative electrode.

15. In the 9th paragraph, the electrolyte is a liquid electrolyte, a solid electrolyte, a gel electrolyte or a combination thereof, and the 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.

16. In the first paragraph, the positive electrode includes a positive electrode collector, and the negative electrode includes a negative electrode collector. 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.

17. Step of providing a cathode current collector; A step of providing a cathode by providing an electrodeposition induction layer on the above cathode current collector; and A step of providing an anode on the cathode and providing an electrolyte layer between the cathode and the anode, A method for manufacturing a lithium metal battery, wherein the electrodeposition-inducing layer contains chromium (Cr).

18. In the 17th paragraph, the step of providing the electrodeposition induction layer includes the step of providing chromium (Cr) on the negative electrode current collector, The step of providing the chromium comprises the step of providing copper particles coated with chromium on the negative electrode collector, A method for manufacturing a lithium metal battery, wherein the step of providing the copper particles coated with the above chromium on the negative electrode collector is performed through a roll press method or a spray method.

19. A method for manufacturing a lithium metal battery, wherein the step of providing the electrodeposition-inducing layer in the 17th paragraph includes the step of treating the negative electrode current collector with a chromate solution.

20. In the 14th paragraph, the step of treating the negative electrode collector with the chromate solution is: A step of preparing a chromate solution by mixing chromate, dichromate, chromic acid, chromate salt compound or a combination thereof with a solvent; and A method for manufacturing a lithium metal battery, comprising a step of contacting the above dichromate solution with the above negative electrode collector, wherein the solvent comprises water, an organic solvent, or any combination thereof.

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