Lithium metal electrode for lithium secondary battery, anode-free electrode for lithium secondary battery, and manufacturing method therefor

Abstract

The present invention relates to a lithium metal electrode, an anode-free electrode, and a manufacturing method therefor, wherein the lithium metal electrode comprises: a current collector; a metal layer disposed on at least one surface of the current collector and including a lithium alloy alloyed with a lithiophilic material; and a protective layer disposed on the metal layer and including a carbon-based material and at least one of a nitrogen-based alloy and a magnesium-based alloy, and does not exhibit a peak value at 17 to 20° in an XRD pattern.

Description

Lithium metal electrode for lithium secondary battery, negative electrode for lithium secondary battery, and method for manufacturing the same

[0001] The present invention relates to a lithium secondary battery, and more specifically, to a lithium metal electrode for a lithium secondary battery, a negative electrode for a lithium secondary battery, and a method for manufacturing the same.

[0002] The present invention claims priority based on Korean Patent Application No. 10-2024-0190999 filed on December 19, 2024, the entire contents of said application incorporated herein by reference.

[0003] To reduce the cost and increase the energy density of rechargeable batteries, it is essential to use lithium metal electrodes as the negative electrodes. Specifically, all-solid-state batteries are recently attracting attention as next-generation batteries for high energy density applications, such as electric vehicles (EVs).

[0004] All-solid-state batteries have various advantages, such as excellent stability because they do not use liquid electrolytes, the ability to operate at high voltages, improved energy density of the battery pack due to the reduction of cooling and safety-related components, and the ability to operate over a wide temperature range. In order to achieve high energy density in such all-solid-state batteries, thick, low-capacity graphite-based anode materials must be replaced with thin, high-capacity lithium materials. Considering economic efficiency and energy density, there is a need for thin-film lithium metal electrodes or anode-free materials with a substantial thickness.

[0005] However, conventional lithium battery technologies, particularly those using lithium metal electrodes and anodes, have faced limitations in performance and safety due to durability issues with the protective layer. Specifically, lithium metal is highly reactive and readily reacts with the electrolyte, causing irreversible side reactions, which acted as a primary cause of battery lifespan and performance degradation.

[0006] A protective layer was introduced to prevent direct reactions between lithium and the electrolyte, but conventional protective layer materials often lacked mechanical and chemical durability, failing to effectively suppress problems such as lithium dendrite growth over time.

[0007] Therefore, it is urgent to develop a more durable and effective protective layer and apply it to lithium metal anode and cathode-electrode batteries. In particular, there is a need to develop a protective layer that prevents reaction with moisture, thereby facilitating lithium electrodeposition and stabilizing mechanical properties.

[0008] The technical problem that the present invention aims to solve is to provide a lithium metal electrode that enables high-speed electrodeposition of lithium and has excellent durability due to the superior strength of the protective layer.

[0009] Another technical problem that the present invention aims to solve is to provide a non-cathode electrode with excellent durability, in which lithium is uniformly electrodeposited on a current collector through battery charging and the protective layer has excellent strength.

[0010] Another technical problem that the present invention aims to solve is to provide a method for manufacturing a lithium metal electrode having the aforementioned advantages.

[0011] According to one embodiment of the present invention, a lithium metal electrode comprises a current collector, a metal layer comprising a lithium alloy alloyed with a lithium-friendly material located on at least one surface of the current collector, and a protective layer disposed on the metal layer comprising a carbon-based material and at least one of a nitrogen-based and magnesium-based alloy, and may not include a peak value at 17 to 20° in the XRD peak value.

[0012] In one embodiment, the bonding strength between the current collector and the protective layer may be 140.0 mN / cm or more. In one embodiment, the XRD peak values ​​may include a peak value at least one of 41 to 43° and 61 to 63°.

[0013] In one embodiment, the content of the nitrogen-based and magnesium-based alloys may be 15 to 70 weight% based on 100 weight% of the protective layer. In one embodiment, the lithium-friendly material may include at least one of In, Ag, Sn, Zn, Si, Al, and Bi.

[0014] According to another embodiment of the present invention, the non-cathode electrode comprises a current collector;

[0015] The above-mentioned current collector may include a metal layer comprising a lithium-friendly material located on at least one surface of the metal layer and a protective layer disposed on the metal layer comprising at least one of a carbon-based material and a nitrogen-based and magnesium-based alloy, and may not include a peak value at 17 to 20° in the XRD peak value.

[0016] A method for manufacturing a lithium metal electrode according to another embodiment of the present invention comprises the steps of preparing a current collector, forming a coating layer on at least one surface of the current collector using a coating composition containing a lithium-friendly component, and forming a protective layer by coating a slurry on the surface of the coating layer, wherein the slurry may include a carbon-based material, a metal nitride, and a non-aqueous solvent.

[0017] In one embodiment, the non-aqueous solvent may include an organic solvent. In one embodiment, the non-aqueous solvent may include at least one of NMP and EG (Ethylene glycol), DMF (dimethylformamide), DMAC (Dimethylacetamide), DMSO (Dimethyl sulfoxide), THF (Tetrahydrofuran), Toluene, and Acetone. In one embodiment, based on 100 weight% of the slurry, the content of the metal nitride may be 5 to 80 weight%.

[0018] In one embodiment, a binder may be further included in the step of forming the protective layer. In one embodiment, the binder may be a non-aqueous binder.

[0019] According to one embodiment of the present invention, a lithium metal electrode for a lithium secondary battery is formed by mixing amorphous carbon and a metal fluoride or a metal nitride in a protective layer and slurrying it using a non-aqueous solvent, thereby suppressing the growth of Mg(OH)2 to improve lithium ion conductivity and increase the lithium stacking speed, and provides an electrode with improved mechanical strength.

[0020] A method for manufacturing a lithium metal electrode for a lithium secondary battery according to another embodiment of the present invention provides a method for minimizing moisture reactivity by minimizing the composition and reactivity within the protective layer slurry by preparing a slurry using a non-aqueous solvent in order to manufacture a lithium metal electrode having the aforementioned advantages.

[0021] Figure 1 shows a lithium metal electrode manufactured according to one embodiment.

[0022] Figure 2 shows a cathode-free electrode manufactured according to one embodiment.

[0023] FIG. 3 is a schematic diagram of a method for manufacturing a lithium metal electrode of the present invention.

[0024] Figure 4 is an XRD analysis pattern according to an embodiment and a comparative example of the present invention.

[0025] FIG. 5 is a diagram comparing the lithium electrodeposition performance according to an embodiment and a comparative example of the present invention.

[0026] FIGS. 6 and 7 are drawings showing the state of the protective layer remaining after a tape test according to an embodiment and a comparative example of the present invention.

[0027] FIGS. 8 and 9 are drawings showing the results of a scratch qualitative evaluation according to an embodiment and a comparative example of the present invention.

[0028] Terms such as first, second, and third are used to describe various parts, components, regions, layers, and / or sections, but are not limited thereto. These terms are used solely to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Accordingly, the first part, component, region, layer, or section described below may be referred to as the second part, component, region, layer, or section without departing from the scope of the present invention.

[0029] The technical terms used herein are for the reference of specific embodiments only and are not intended to limit the invention. The singular forms used herein include plural forms unless phrases clearly indicate otherwise. As used in the specification, the meaning of "comprising" specifies certain characteristics, areas, integers, steps, actions, elements, and / or components, and does not exclude the presence or addition of other characteristics, areas, integers, steps, actions, elements, and / or components.

[0030] When it is stated that one part is "on" or "on" another part, it may be directly on or on the other part, or another part may be involved in between. In contrast, when it is stated that one part is "directly on" another part, no other part is interposed in between.

[0031] Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as generally understood by those skilled in the art to which this invention pertains. Terms defined in commonly used dictionaries are further interpreted to have meanings consistent with relevant technical literature and the present disclosure, and are not interpreted in an ideal or highly formal sense unless otherwise defined.

[0032] FIG. 1 shows a lithium metal electrode (100) manufactured according to one embodiment.

[0033] Referring to FIG. 1, a lithium metal electrode (100) according to one embodiment comprises a current collector (10), a metal layer (20) disposed on at least one surface of the current collector (10), and a protective layer (30) disposed on the metal layer (20). When forming the protective layer (30) of the lithium metal electrode (100) of the present invention, a non-aqueous solvent in the slurry is used to form a protective layer that does not contain Mg(OH)2 in the final product. The inventors have discovered that when nitrogen-based and magnesium-based alloys are formed in the protective layer of the lithium metal electrode (100), a non-aqueous solvent is added so that there is no reactivity with Mg3N2, and thus Mg(OH)2 is not formed, making it possible to manufacture a lithium metal electrode with high bonding strength and excellent durability.

[0034] The current collector (10) may be a component for electrical connection within a lithium secondary battery. The current collector (10) may have the form of a foil, but is not limited thereto, and may have the form of, for example, a mesh, foam, rod, wire, or a sheet woven from wire or fiber.

[0035] The current collector (10) may be made of a material that is electrically conductive and has limited reaction with lithium. Specifically, the material of the current collector (10) may be, for example, copper, nickel, titanium, stainless steel, gold, platinum, silver, tantalum, ruthenium, and alloys thereof, carbon, a conductive polymer, a composite fiber with a conductive layer coated on a non-conductive polymer, or a combination thereof.

[0036] In one embodiment, the thickness of the current collector (10) may be 1 μm to 50 μm. If the thickness of the current collector (10) is excessively thick, there is a problem that the battery weight increases and the energy density of the battery decreases. If the thickness of the current collector (10) is excessively thin, there is a risk of overheating damage during high-current operation and damage due to tension during the battery manufacturing process.

[0037] The metal layer (20) is located on the current collector (10) and may include a lithium alloy layer (21) containing a lithium alloy and a lithium metal layer (22) located on the lithium alloy layer (21). The lithium alloy layer (21) may be a layer comprising a lithium alloy in which lithium precipitated from the lithium source (40) is alloyed with a lithium-friendly material contained in the metal layer (20) on the current collector (10) by applying current between the current collector (10) and the lithium source (40 in FIG. 2).

[0038] When the electrodeposition process is carried out by applying a high current to increase the speed of electrodeposition when forming the metal layer (20), there is a problem that the performance of the lithium secondary battery is degraded. However, when the metal layer (20) is formed with a structure including a lithium alloy layer (21) containing a lithium component as in the present embodiment, even if the electrodeposition process is performed by applying a high current, it is possible to prevent the excessive generation of fine lithium particles or the destruction of the protective layer (30) located on the lithium metal layer (22) already formed during the electrodeposition process.

[0039] Specifically, since the metal layer (20) of one embodiment includes a lithium alloy layer (21) containing a lithium component, when a high current is applied in the electrodeposition process to form a lithium metal layer (22) on the lithium alloy layer (21), the lithium particles initially generated are induced to grow well so that particles with a coarse structure are formed, and at the same time, the lithium metal layer (22), and consequently the metal layer (20), can have a uniform surface.

[0040] Accordingly, the performance of a secondary battery using a lithium metal electrode according to the present embodiment, specifically the charge / discharge characteristics, can be significantly improved. In addition, since a lithium metal electrode for a secondary battery with high performance can be manufactured even when a high current is applied and the electrodeposition process is performed at a high speed, the productivity of the lithium metal electrode for a secondary battery can also be significantly improved.

[0041] In this embodiment, the lithium alloy layer (21) includes a lithium-friendly material. The lithium-friendly material may be, for example, one or more selected from the group consisting of In, Ag, Sn, Zn, Si, Al, and Bi. When the lithium alloy layer (21) includes a lithium-friendly material in this way, since it includes a lithium-friendly material with high electron conductivity, electrons are smoothly supplied from the current collector, and lithium ions are reduced, thereby providing the advantage of easily performing electrodeposition of the lithium metal layer. The metal layer (20) plays a role in helping lithium to be deposited more effectively on the underside of the protective layer (30) during the charging process of the battery.

[0042] In one embodiment, the thickness of the metal layer (20) may be in the range of 1 μm to 100 μm, more specifically, 5 μm to 30 μm. If the thickness of the metal layer (20) is excessively thick, when the lithium metal electrode of this embodiment is applied to a secondary battery, there is a problem in that the weight and volume of the battery increase, resulting in a lower energy density. In addition, since the time and cost of the electrodeposition process increase in proportion to the thickness when forming the metal layer (20), it is preferable that the thickness of the metal layer (20) be 100 μm or less.

[0043] When the thickness of the metal layer (20) is excessively thin, there is a problem that the charge / discharge life of the battery is reduced when the lithium metal electrode of the present embodiment is applied to a secondary battery. Specifically, during the charge / discharge of the battery, lithium in the battery is gradually consumed due to side reactions between the lithium contained in the negative electrode active material layer, i.e., the metal layer of the present invention, and the electrolyte, and the battery capacity decreases, and the amount of lithium retained to replenish the lithium consumed during the charge / discharge decreases as the battery's charge / discharge life decreases. Therefore, it is preferable that the thickness of the metal layer (20) be 1 μm or more.

[0044] The protective layer (30) is disposed on at least one surface of the current collector (10) and may include at least one of a carbon-based material and a nitrogen-based and magnesium-based alloy. The carbon-based material may include, for example, amorphous carbon. The amorphous carbon may be, for example, one or more selected from the group consisting of acetylene black, super P black, carbon black, denka black, activated carbon, graphite, hard carbon, and soft carbon, but is not limited thereto. The amorphous carbon may be in powder form.

[0045] The above nitrogen-based and magnesium-based alloy may be Mg3N2. Specifically, the protective layer (30) includes Mg3N2 as the above nitrogen-based and magnesium-based alloy so that even if lithium is electrodeposited and the battery is charged, the lithium can precipitate and reduce dendrite growth. In addition, by including the above nitrogen-based and magnesium alloy in the protective layer (30), the bonding strength between the protective layer (30) and the current collector (10) can be improved.

[0046] In one embodiment, the lithium metal electrode (100) may not include a peak value at 17 to 20° in the XRD peak value. The peak value at 17 to 20° represents Mg(OH)2, and the lithium metal electrode (100) of the present invention may not include Mg(OH)2. In forming the protective layer (30), the present invention may not include Mg(OH)2 because, unlike when using an aqueous solvent, a non-aqueous solvent is used so that Mg3N2 does not react with H2O. If Mg(OH)2 is included in the protective layer (30), it provides an environment where lithium can precipitate and dendrites can grow, which may cause a problem of side reactions with the electrolyte.

[0047] In one embodiment, the lithium metal electrode (100) may include a peak value at least one of 41 to 43° and 61 to 63° in the XRD peak value. Specifically, 41 to 43° and 61 to 63° represent peaks of Mg3N2, and by including the said peaks contained within the protective layer (30), the durability of the electrode can be improved and dendrite growth can be suppressed.

[0048] In one embodiment, the lithium metal electrode (100) may have a bonding strength between the current collector (10) and the protective layer (30) of 140.0 mN / cm or more. Specifically, the bonding strength may be 140.0 to 160.0 mN / cm. By satisfying the aforementioned range of bonding strength, a durable electrode can be formed to suppress dendrite growth.

[0049] In one embodiment, the thickness of the protective layer (30) may be from 0.01 μm to 50 μm. Specifically, the thickness of the protective layer (30) may be in the range of 1 μm to 20 μm. By satisfying the above-mentioned range, an ultra-thin lithium metal electrode can be provided.

[0050] If the thickness of the protective layer (30) exceeds the upper limit of the aforementioned range, the resistance of the protective layer becomes excessively high, which can cause an increase in overvoltage during secondary battery operation and cause a decrease in battery energy density due to an increase in weight and volume. If the thickness of the protective layer (30) exceeds the lower limit of the aforementioned range, there is a problem that it cannot perform the function of a protective layer.

[0051] In one embodiment, the protective layer (30) may include a binder. The binder may be a non-aqueous binder. The non-aqueous binder may include at least one selected from PVDF (polyvinylidene fluoride), PVDF-HFP (polyvinylidene fluoride-hexafluoropropylene copolymer), PTFE (polytetrafluoroethylene), PAI (polyamideimide), PEO (polyethylene oxide), PANI (polyaniline), PDO (polypyrrole), and polythiophene.

[0052] In the present invention, the lithium metal electrode (100) includes the non-aqueous binder as a binder in the protective layer (30), thereby suppressing the formation of Mg(OH)2 in the protective layer (30), and thus can realize a high-strength electrode that suppresses the growth of dendrites.

[0053] In one embodiment, the binder may be included in an amount of 1 to 20 weight% based on 100 weight% of the protective layer (30). Specifically, the binder may be included in an amount of 3 to 15 weight%, more specifically, 5 to 10 weight%. When the content of the binder satisfies the aforementioned range, there is an advantage in that the binding strength of Mg3N2 is improved, thereby enabling the realization of an electrode with excellent bonding strength.

[0054] If the content of the binder is excessively low compared to the aforementioned range, there is a problem of reduced inter-particle bonding strength when forming the protective layer; and if the content of the binder is excessively high compared to the aforementioned range, not only does it cause a decrease in energy density, but the resistance of the protective layer also increases significantly, which hinders lithium ion conduction.

[0055] In one embodiment, an alloy layer may be further included in at least one region between the metal layer (20) and the protective layer (30) and within the protective layer (30). The alloy layer may be formed during the process of lithium electrodeposition.

[0056] For example, the alloy layer may be a magnesium alloy layer. The alloy layer may be formed by Mg3N2 reacting with lithium to form a Li-Mg alloy. By further including the alloy layer, it is advantageous for lithium ion conductivity and has excellent mechanical properties, so when applied to a battery, the charge and discharge performance of the battery can be improved.

[0057] In one embodiment, the alloy layer may be disposed in at least one region between the metal layer (20) and the protective layer (30) and inside the protective layer (30). Specifically, since the alloy layer is formed by reacting lithium with a magnesium-based nitride in the protective layer during the lithium electrodeposition process, the alloy layer may be formed between the metal layer (20) and the protective layer (30), and may be disposed inside the protective layer (30), for example, in the lower region of the protective layer (30).

[0058] FIG. 2 shows a non-cathode electrode (200) manufactured according to one embodiment.

[0059] Referring to FIG. 2, the non-cathode electrode (200) may include a metal layer (20') containing a lithium-friendly material located on at least one surface of the current collector (10) and a protective layer disposed on the metal layer (20') and containing at least one of a carbon-based material and a nitrogen-based and magnesium-based alloy. The non-cathode electrode (200) may not contain lithium within the electrode, and when charging is performed at the battery terminal, lithium is transferred from the positive electrode, and the lithium is electrodeposited on the current collector to form a lithium layer.

[0060] In this way, the non-cathode electrode (200) may mean a state in which, when manufacturing the lithium metal electrode in FIG. 1, a lithium electrodeposition step is not included, and a metal layer (20) containing a lithium-friendly material is disposed on a current collector (10), and a protective layer (30) is disposed on the metal layer (20).

[0061] The current collector (10) may be a component for electrical connection within a lithium secondary battery. The current collector (10) may have the form of a foil, but is not limited thereto, and may have the form of, for example, a mesh, foam, rod, wire, or a sheet woven from wire or fiber.

[0062] The current collector (10) may be made of a material that is electrically conductive and has limited reaction with lithium. Specifically, the material of the current collector (10) may be, for example, copper, nickel, titanium, stainless steel, gold, platinum, silver, tantalum, ruthenium, and alloys thereof, carbon, a conductive polymer, a composite fiber with a conductive layer coated on a non-conductive polymer, or a combination thereof.

[0063] In one embodiment, the thickness of the current collector (10) may be 1 μm to 50 μm. If the thickness of the current collector (10) is excessively thick, there is a problem that the battery weight increases and the energy density of the battery decreases. If the thickness of the current collector (10) is excessively thin, there is a risk of overheating damage during high-current operation and damage due to tension during the battery manufacturing process.

[0064] The metal layer (20) is located on the current collector (10) and may include a lithium-friendly material. The lithium-friendly material may be, for example, one or more selected from the group consisting of In, Ag, Sn, Zn, Si, Al, and Bi. In this way, when the lithium alloy layer (21) includes a lithium-friendly material, electrons are smoothly supplied from the current collector and lithium ions are reduced so that when lithium is formed on the current collector during lithium charging, it can be formed uniformly.

[0065] The protective layer (30) is disposed on at least one surface of the current collector (10) and may include at least one of a carbon-based material and a nitrogen-based and magnesium-based alloy. The carbon-based material may include, for example, amorphous carbon. The amorphous carbon may be, for example, one or more selected from the group consisting of acetylene black, super P black, carbon black, denka black, activated carbon, graphite, hard carbon, and soft carbon, but is not limited thereto. The amorphous carbon may be in powder form.

[0066] The above nitrogen-based and magnesium-based alloy may be Mg3N2. Specifically, the protective layer (30) includes Mg3N2 as the above nitrogen-based and magnesium-based alloy so that even if lithium is electrodeposited and the battery is charged, the lithium precipitates and dendrite growth can be reduced. In addition, by including the above nitrogen-based and magnesium alloy in the protective layer (30), the bonding strength between the protective layer (30) and the current collector (10) can be improved. The detailed description of the protective layer (30) is the same as that of FIG. 1 to the extent that it does not contradict FIG. 1.

[0067] FIG. 3 is a schematic diagram of a method for manufacturing a lithium metal electrode (100) of the present invention.

[0068] Referring to FIG. 3, a method for manufacturing a lithium metal electrode (100) according to one embodiment includes the steps of preparing a current collector (10), forming a coating layer (20) on at least one surface of the current collector (10) using a coating composition containing a lithium-friendly component, and forming a protective layer (30) by coating a slurry on the surface of the coating layer. The inventors confirmed that when a non-aqueous solvent is used with amorphous carbon and metal fluoride in the step of forming the protective layer (30), Mg(OH)2 that is expressed when an aqueous solvent is used is not generated, so a protective layer with excellent bonding strength is formed, and accordingly, the durability of the electrode is improved and the growth of dendrites can be suppressed.

[0069] In the step of preparing the current collector (10), the current collector (10) may be made of a material that has electrical conductivity and has limited reaction with lithium. Specifically, the material of the current collector (10) may be, for example, copper, nickel, titanium, stainless steel, gold, platinum, silver, tantalum, ruthenium, and alloys thereof, carbon, a conductive polymer, a composite fiber with a conductive layer coated on a non-conductive polymer, or a combination thereof.

[0070] In one embodiment, the step of forming the coating layer (20) may be performed using at least one method among electrolytic and electroless plating, sputtering, electron beam, and thermal vapor deposition. For example, the step of forming the coating layer (20) may be performed by an electroless plating method. The step of forming the coating layer (20) may be a step of coating a lithium-friendly material onto a current collector (10).

[0071] A protective layer (30) can be formed on the surface of a coating layer (20) using a slurry containing amorphous carbon. The protective layer (30) can be formed by applying a slurry formed by mixing the amorphous carbon and a binder in a non-aqueous solvent using at least one of the doctor blade method, dip method, reverse roll method, direct roll method, gravure method, extrusion method, and brush application method.

[0072] In one embodiment, the slurry may include at least one of amorphous carbon and a metal nitride. Specifically, the metal nitride may be, for example, Mg3N2 or Ag3N. By including a metal material containing not only amorphous carbon but also a metal nitride in the slurry, a protective layer (30) can be formed that is advantageous for lithium ion conductivity and mechanical properties and prevents the growth of dendrites. Additionally, by including a metal material containing at least one of the metal nitrides, an alloy layer containing at least one of a nitrogen-based and a magnesium-based alloy can be formed during the subsequent lithium electrodeposition process to improve the performance of the battery.

[0073] In one embodiment, based on 100 weight% of the slurry, the content of the amorphous carbon may be 20 to 90 weight%. Specifically, the content of the amorphous carbon may be 30 to 80 weight%, and more specifically, 40 to 60 weight%. By including the content of amorphous carbon in the slurry within the aforementioned range, the maximum current density during lithium electrodeposition can be improved to increase electrodeposition efficiency, and there is an advantage in that the number of charge-discharge cycles of the battery is increased, thereby improving lifespan characteristics.

[0074] In one embodiment, based on 100 weight% of the slurry, the content of the metal nitride may be 5 to 80 weight%. Specifically, the content of the metal nitride may be 10 to 70 weight%, more specifically, 20 to 60 weight%.

[0075] When the content of the above-mentioned amorphous carbon is excessively high, the content of the metal material containing the metal nitride becomes excessively low, resulting in a lack of magnesium-based alloys or nitrogen-based alloys, which hinders the improvement of lithium-ion conductivity. When the content of the above-mentioned amorphous carbon is excessively low, the content of the metal material containing the metal nitride becomes excessively high, resulting in an excessive amount of magnesium-based alloys or nitrogen-based alloys. Consequently, the amount of lithium available to replenish the lithium consumed during charging and discharging decreases, leading to a problem where the charge / discharge life of the battery is reduced or mechanical strength is reduced.

[0076] In one embodiment, the slurry may include a binder. The binder may be an aqueous or non-aqueous binder.

[0077] In the present invention, when forming a protective layer, Mg3N2 is slurried with a non-aqueous solvent and then coated, thereby solving the problem of high-speed electrodeposition of lithium due to Mg(OH)2 and improving the strength of the protective coating layer, thereby enabling the realization of an electrode with excellent durability. The inventors confirmed that when an aqueous solvent is used as a solvent when forming a protective layer, there is a problem in that it reacts with the metal fluoride, which is a component of the protective layer of the present invention, to form by-products such as Mg(OH)2. To solve this, the aqueous solvent was replaced with a non-aqueous solvent, and as a result, it was found that a slurry is easily formed without reacting separately with the metal fluoride.

[0078] In this way, a protective layer (30) can be formed on the surface of a current collector (10) by slurrying a carbon-based material and a metal nitride in a non-aqueous solvent. The protective layer (30) can be formed by applying a slurry formed by mixing the amorphous carbon and binder in a solvent using at least one of the doctor blade method, dip method, reverse roll method, direct roll method, gravure method, extrusion method, and brush coating method.

[0079] In one embodiment, the solvent may be a non-aqueous solvent. Specifically, the non-aqueous solvent may include, as a non-limiting example, at least one of NMP (N-Methyl-2-pyrrolidone), EG (Ethylene glycol), DMF (dimethylformamide), DMAC (Dimethylacetamide), DMSO (Dimethyl sulfoxide), THF (Tetrahydrofuran), Toluene, and Acetone. The non-aqueous solvent may contribute to improving the durability of the protective layer by enhancing the binding strength of the binder.

[0080] In one embodiment, the step of forming the protective layer (30) may involve coating the slurry in a range of 3 to 10 μm. Specifically, the range may be coated in a range of 4 to 7 μm. As the slurry is coated in the aforementioned range, it not only serves as a protective layer by having an appropriate thickness of the protective layer (30), but also prevents the formation of lithium dendrites on the surface of the protective layer due to the effect of having appropriate resistance for the movement of lithium ions, and assists in allowing conduction to penetrate well into the interior of the protective layer (30), thereby enabling lithium to precipitate on the lower surface of the protective layer.

[0081] If the thickness of the protective layer is excessively thin, there is a problem in that it cannot perform its function as a protective layer. If the thickness of the protective layer is excessively thick, the resistance of the protective layer becomes excessively high, which can cause an increase in overvoltage during the operation of the secondary battery and cause a decrease in battery energy density due to an increase in weight and volume. However, the thickness of such a protective layer can be variably adjusted according to the design of the secondary battery structure.

[0082] In one embodiment, a method for manufacturing a lithium metal electrode comprises, after the step of forming a protective layer (30), the step of positioning a current collector (10) having the protective layer (30) formed thereon in a plating solution (50) and then positioning a lithium source (40) at a predetermined distance from the protective layer (30), and the step of applying a current between the current collector and the lithium source (40) to form a metal layer comprising a lithium alloy in which the lithium-friendly component included in the coating layer and the lithium precipitated from the lithium source (40) are alloyed. However, this is a non-limiting example, and it is clear that the non-cathode electrode (200) described in FIG. 2 can be utilized as is without a separate process of electrodepositing lithium.

[0083] After the step of forming the protective layer (30), the current collector (10) having the protective layer (30) formed thereon is placed in the plating solution (50), and then a lithium source (40) is placed at a predetermined distance from the current collector (10), and a metal layer (20) is formed by applying current between the current collector (10) and the lithium source (40).

[0084] Specifically, a current collector (10) having a protective layer (30) formed thereon is positioned within a plating solution, and then a lithium source (40) is positioned at a predetermined distance from the protective layer (30). The lithium source (40) may be, for example, lithium metal, a lithium alloy, a foil formed by pressing the lithium metal or lithium alloy onto a current collector, a plating solution in which a lithium salt is dissolved, etc.

[0085] The plating solution (50) can be prepared by dissolving a lithium salt in a plurality of solvents. Specifically, the lithium salt may be LiCl, LiBr, LiI, LiCO3, LiNO3, LiFSI, LiTFSI, LiBF4, LiPF6, LiAsF6, LiClO4, LiN(SO2CF3)2, LiBOB, or a combination thereof. The concentration of the lithium salt may be 1.0 to 3.0 M based on the total electrolyte.

[0086] Specifically, in this embodiment, the plating solution (50) is characterized by comprising a nitrogen-based compound as at least one of the lithium salt and a plurality of solvents. The nitrogen-based compound may include, for example, one or more selected from the group consisting of lithium nitrate, lithium bis fluorosulfonyl imide, lithium bis trifluoromethane sulfonimide, e-caprolactam, N-methyl-e-caprolactam, triethylamine, and tributylamin.

[0087] Among the above nitrogen-based compounds, at least one of lithium nitrate, lithium bis fluorosulfonyl imide, and lithium bis trifluoromethane sulfonimide can be used as a lithium salt.

[0088] Among the above nitrogen compounds, at least one of caprolactam (e-caprolactam), methyl caprolactam (N-methyl-e-caprolactam), triethylamine (triethylamine) and tributylamin (tributylamin) can be used as a non-aqueous solvent.

[0089] The plating solution (50) may be prepared using only the above nitrogen-based compound, but may include a general non-aqueous solvent as an auxiliary solvent considering the viscosity of the plating solution (50).

[0090] The above auxiliary solvent may comprise, for example, one or more selected from the group consisting of ethylene carbonate, propylene carbonate, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, 1,2-dimethoxyethane, diethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, and 1,3,5-trioxane.

[0091] In one embodiment, the auxiliary solvent may be included in an amount of 5 to 70 weight%, preferably 10 to 60 weight%, with respect to 100 weight% of the total plating solution (50), but is not limited thereto. However, when the auxiliary solvent is included within the above range, the viscosity of the plating solution (50) is appropriate so that the electrodeposition time can be shortened, but is not limited thereto.

[0092] In one embodiment, the plating solution (50) may further include a fluorine-based compound. When the plating solution (50) further includes the fluorine-based compound, there is an advantage in that the properties of the film layer on the metal layer or protective layer can be improved.

[0093] The above-mentioned fluorine compounds are, for example, lithium difluorophosphate, lithium hexafluorophosphate, lithium difluorobisoxalatophosphate, lithium tetrafluorooxalatophosphate, lithium difluorooxalate borate, lithium difluorooxalatoborate, lithium tetrafluorooxalatoborate, fluoroethylene carbonate, difluoroethylene carbonate, and 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether. It may include one or more selected from the group consisting of ether.

[0094] The above fluorine-based compound may be included in an amount of 0.1 to 30 weight%, preferably 1 to 20 weight%, and more preferably 1 to 10 weight% based on 100 weight% of the total plating solution (50). When the above fluorine-based compound is included within the above range, the interaction between the nitrogen-based compound and the above fluorine-based compound in the plating solution (50) is smooth, which has the advantage of excellent improvement in the properties of the film layer. In addition, it has the advantage of excellent electrochemical properties by suppressing the excessive generation of LiF, etc., caused by the direct reaction between the above fluorine-based compound and lithium.

[0095] Next, an insulating film is positioned between the current collector (10) and the lithium source (40), and then the current collector (10), the lithium source (40), and the insulating film can be stacked and constrained from both directions using a restraining device. The restraining device may use methods commonly used in the industry, such as manual clamping, hydraulic, pneumatic, or uniaxial pressure methods, as a non-limiting example.

[0096] The current density of the current applied in the step of forming a metal layer containing lithium on at least one surface of the current collector by applying the above current is 0.1 mA / cm² 2 Up to 100 mA / cm 2 Range, more specifically 0.2 mA / cm 2 Up to 50 mA / cm 2 Range, 5 mA / cm 2 Up to 30 mA / cm 2 Range or 7 mA / cm 2 Up to 25 mA / cm 2 It can be a range.

[0097] In one embodiment, the time for applying the current may be in the range of 0.05 hours to 50 hours, more specifically in the range of 0.25 hours to 25 hours.

[0098] In one embodiment, the step of forming a lithium metal layer on at least one surface of the current collector by applying the current may be performed at least once at different current densities. The step of applying the current may be performed in multiple stages. Specifically, the step of applying the current in multiple stages may be performed by increasing the current density from a low current density to a high current density in predetermined time steps. For example, the step of applying the current may be 0.1 to 0.3 mA / cm² 2 , 0.3 to 0.7 mA / cm 2 , and 0.8 to 1.5 mA / cm 2 Electroplating can be performed by increasing the steps in order.

[0099] In one embodiment, the step of forming a metal layer (20) on at least one surface of the current collector (10) by applying the current is 6 to 12 mA / cm 2 The method may include a step of electrodeposition at a maximum current density in the range of 8 to 12 mA / cm². Specifically, the maximum current density is 8 to 12 mA / cm². 2 It can be performed within a range. The above maximum current density refers to the limit of the current density at which lithium can be deposited between the protective layer (30) and the current collector (10) during the electrodeposition process.

[0100] The step of electrodeposition at the maximum current density described above may be a final step performed after a multi-stage deposition step for lithium deposition between the current collector (10) and the protective layer (30), for example. By satisfying the aforementioned range of maximum current density, lithium is properly deposited between the current collector (10) and the protective layer (30), thereby providing the advantage of excellent battery life characteristics and bonding strength between the current collector (10) and the protective layer (30).

[0101] If the above maximum current density exceeds the upper limit of the aforementioned range, there is a problem in that the target stabilized electrode structure cannot be secured because lithium is deposited on the surface of the protective layer (30). If the above maximum current density exceeds the lower limit of the aforementioned range, there is a problem of reduced productivity because the time for lithium to be electrodeposited increases.

[0102] In one embodiment, the step of forming a lithium metal layer on at least one surface of the current collector by applying the current may include the step of electrodepositing the thickness of the deposited lithium in the range of 5 to 15 μm. Specifically, the thickness of the deposited lithium may be electrodeposited in the range of 8 to 12 μm. The thickness of the deposited lithium may refer to the height in the vertical direction of the lithium disposed between the current collector (10) and the protective layer (30).

[0103] If the thickness of the precipitated lithium exceeds the upper limit of the aforementioned thickness, there is a problem in that not only is the energy density of the battery reduced, but the process time and the amount of metal raw material used increase during the formation of the metal layer. If the thickness of the precipitated lithium exceeds the lower limit of the aforementioned thickness, there is a problem in that the initial Coulomb efficiency is reduced due to initial irreversibility and the charge / discharge performance is reduced because there is a shortage of excess lithium.

[0104] According to another embodiment of the present invention, a lithium secondary battery comprises a positive electrode, a negative electrode, and an electrolyte located between the positive electrode and the negative electrode. Herein, the negative electrode may be a lithium metal electrode according to the present invention.

[0105] In one embodiment, a lithium secondary battery may comprise an electrode assembly comprising a positive electrode including a positive active material, a lithium metal electrode or a negative electrode of the present invention replacing the negative electrode, and a separator disposed between the positive electrode and the lithium metal electrode or negative electrode. Such an electrode assembly may be wound or folded and accommodated in a battery case.

[0106] Subsequently, an electrolyte is injected into the battery case and sealed to complete the secondary battery. At this time, the battery case may have a shape such as a cylindrical, prismatic, pouch, or coin type.

[0107] The above-mentioned anode may include an anode active material layer and an anode current collector. The above-mentioned anode active material layer may include, for example, a Li compound comprising at least one metal selected from the group consisting of Ni, Co, Mn, Al, Cr, Fe, Mg, Sr, V, La, and Ce, and at least one non-metal element selected from O, F, S, P, and combinations thereof.

[0108] In one embodiment, a conductive material may be further added to the positive active material layer. The conductive material may be, for example, carbon black and ultrafine graphite particles, fine carbon such as acetylene black, nano metal particle paste, etc., but is not limited thereto.

[0109] The above positive current collector serves to support the above positive active material layer. As the positive current collector, for example, an aluminum foil, a nickel foil, or a combination thereof may be used, but is not limited thereto.

[0110] The electrolyte filled in the above lithium secondary battery may be a non-aqueous electrolyte or a solid electrolyte. Specifically, the electrolyte may be a solid electrolyte. The above non-aqueous electrolyte may include, for example, a lithium salt such as lithium hexafluorophosphate or lithium perchlorate and a solvent such as ethylene carbonate, propylene carbonate, or butylene carbonate. In addition, the above solid electrolyte may be, for example, a gel-type polymer electrolyte in which an electrolyte is impregnated into a polymer electrolyte such as polyethylene oxide or polyacrylonitrile, or an inorganic solid electrolyte such as LiI or Li3N.

[0111] The above-mentioned separator separates the positive electrode from the lithium metal electrode or the negative electrode and provides a pathway for the movement of lithium ions; any separator commonly used in lithium secondary batteries may be used. Specifically, the separator may be one that has low resistance to the movement of electrolyte ions and excellent electrolyte wettability. The separator may be selected from, for example, glass fiber, polyester, polyethylene, polypropylene, polytetrafluoroethylene, or a combination thereof, and may be in the form of a nonwoven or woven fabric. Meanwhile, if a solid electrolyte is used as the electrolyte, the solid electrolyte may also serve as the separator.

[0112] Embodiments of the present invention will be described in detail below. However, these are presented as examples and are not intended to limit the present invention, and the present invention is defined only by the scope of the claims set forth below.

[0113]

[0114] Experimental Example 1: Whether to use non-aqueous solvents

[0115] Manufacturing of non-cathode electrodes for lithium secondary batteries

[0116] <Example 1>

[0117] <Whole House Manufacturing>

[0118] A nickel (Ni) current collector was prepared to be used as the negative electrode for the lithium secondary battery of the present invention.

[0119]

[0120] <Formation of coating layer>

[0121] A lithium-friendly material was coated on both sides of the nickel (Ni) current collector using an electroplating method. At this time, silver (Ag) was used as the lithium-friendly material, and the plating thickness was approximately 100 nm.

[0122]

[0123] Formation of a protective layer

[0124] A protective layer of approximately 5 μm was formed on the upper surface of the above coating layer by slurry coating using a comma coater. Specifically, a slurry was prepared to form the protective layer, and the slurry consisted of a mixture of amorphous carbon and a metal nitride, additionally mixed with a non-aqueous binder and a non-aqueous solvent. At this time, acetylene black was used as the amorphous carbon, and magnesium nitride (Mg3N2) was used as the metal nitride. At this time, NMP, an organic solvent, was used as the non-aqueous solvent.

[0125] At this time, based on 100 wt% of the solid content of the protective layer slurry, 76 wt% of amorphous carbon, 19 wt% of metal nitride, and 5 wt% of PVDF as a binder were added to prepare it.

[0126]

[0127] Manufacturing of lithium metal electrodes for lithium secondary batteries

[0128] <Lithium Electrodeposition Process>

[0129] Subsequently, to form a lithium alloy or pure lithium metal between the protective layer and the current collector, lithium was separated from the lithium source using an electrodeposition process and deposited between the protective layer and the current collector. The plating solution used for such electrodeposition was prepared by adding 40% by weight of lithium bis(fluorosulfonyl)imide and 5% by weight of lithium nitrate, which are nitrogen-based compounds, and 5% by weight of fluoroethylene carbonate, which is a fluorine-based compound, to 1,2-dimethoxyethane solvent, based on 100% by weight of the plating solution, and adding 5% by weight of fluoroethylene carbonate, which is a fluorine-based compound, based on 100% by weight of the plating solution.

[0130] A lithium metal plate with a purity of 99.9% or higher and a thickness of 500 μm was pressed onto a copper current collector (Cu Plate) and used as a lithium source. After stacking the lithium source and the current collector in an electrically insulated state within the plating solution, lithium was deposited between the current collector and the composite protective layer by applying current using a power supply, with the lithium source and the current collector serving as the (+) and (-) electrodes, respectively.

[0131] The current density of the electrodeposition process is 0.2 mA / cm² 2 , 0.5 mA / cm 2 , 1 mA / cm 2 After electrodepositing for 5 minutes each while increasing in steps in sequence, 10 mA / cm² 2The maximum current density was set. The electrodeposition time at the maximum current density was calculated as the time required to electrodeposit a final accumulated lithium thickness of 10 μm, and was set variably according to the magnitude of the maximum current density.

[0132]

[0133] <Comparative Example 1> - Use of aqueous solvent

[0134] To prepare a slurry used for forming a protective layer, the procedure was carried out in the same manner as in Example 1, except that based on 100 wt% of the solid content of the protective layer slurry, 76 wt% of amorphous carbon, 19 wt% of the metal nitride Mg3N2, and 5 wt% of PVA-g-PAA were added as a binder, and water (H2O), an aqueous binder, was used as a solvent.

[0135]

[0136] <Example 2> - Mg3N2 content 40%

[0137] To prepare a slurry used for forming a protective layer, the procedure was carried out in the same manner as Example 1, except that 55 wt% of amorphous carbon, 40 wt% of metal nitride, and 5 wt% of PVDF as a binder were added based on 100 wt% of the solid content of the protective layer slurry.

[0138]

[0139] <Comparative Example 2> - Mg3N2 content 10%

[0140] To prepare a slurry used for forming a protective layer, the procedure was carried out in the same manner as Comparative Example 1, except that 55 wt% of amorphous carbon, 10 wt% of metal nitride, and 5 wt% of PVA-g-PAA as a binder were added based on 100 wt% of the solid content of the protective layer slurry.

[0141]

[0142] <Evaluation Example 1> : XRD Pattern Analysis

[0143] Figure 4 is an XRD analysis pattern according to an embodiment and a comparative example of the present invention.

[0144] Figure 4 shows the XRD analysis patterns of Example 1 and Comparative Example 1. The XRD analysis patterns were obtained by performing phase analysis on the samples through XRD analysis evaluation by Rikaku. The evaluation was performed in thin film mode during XRD analysis.

[0145] Specifically, referring to FIG. 4, in the case of Comparative Example 1 using an aqueous solvent, it can be seen that Mg(OH)2 is generated by the reaction between Mg3N2 and the H2O solvent. The Mg(OH)2 is a compound with ionic bonds and can interact with lithium to form LiOH or other lithium compounds. As the lithium compounds are formed, the lithium ion conductivity or stability within the protective layer may be reduced during the battery charging process.

[0146] In addition, Mg(OH)2 can reduce surface stability when lithium is electrodeposited on a current collector in a high current density environment, which can have a negative effect on inhibiting dendrite growth.

[0147] In contrast, in the case of Example 1 using NMP, a non-aqueous solvent, it can be seen that Mg(OH)2 is not generated separately, unlike Comparative Example 1. This is because the solvent did not react separately with the Mg3N2 of the protective layer.

[0148] Therefore, it can be confirmed that the lithium metal electrode or non-cathode electrode of the present invention can prevent the formation of Mg(OH)2 by using a non-aqueous binder in the protective layer.

[0149]

[0150] <Evaluation Example 2> : Evaluation based on electrodeposition performance

[0151] FIG. 5 is a diagram comparing the lithium electrodeposition performance according to an embodiment and a comparative example of the present invention.

[0152] Referring to FIG. 5, for the lithium metal electrodes prepared according to the examples and comparative examples, the current density is 6 mA / cm² 2, 8 mA / cm 2 , 10 mA / cm 2 , and 12 mA / cm 2 The performance was compared when lithium was electrodeposited by setting the method. When comparing Example 1 and Comparative Example 1, it can be seen that high-speed electrodeposition is possible in Example 1 using a non-aqueous solvent, whereas high-speed electrodeposition is disadvantageous in Comparative Example 1 using an aqueous solvent. In addition, it can be seen that Comparative Examples 1 and 2 using an aqueous solvent and Examples 1 and 2 using a non-aqueous solvent have excellent electrodeposition performance even when lithium is electrodeposited at high speed.

[0153] As such, by examining Example 2 and the comparative examples, it was confirmed that even when the content of Mg3N2 increases, the electrodeposition performance remains excellent by using a non-aqueous solvent.

[0154]

[0155] <Evaluation Example 3> : Comparison of Mechanical Properties

[0156] FIGS. 6 and 7 are drawings showing the state of the protective layer remaining after a tape test according to an embodiment and a comparative example of the present invention.

[0157] FIGS. 8 and 9 are drawings showing the results of a scratch qualitative evaluation according to an embodiment and a comparative example of the present invention.

[0158] FIGS. 6 and 8 are drawings according to Comparative Example 1, and FIGS. 7 and 9 are drawings according to Example 1.

[0159] In the tape test, the bonding strength between the coating layer and the current collector was measured using a peel strength tester. Specifically, a 10 mm wide polyimide tape (No. 360A, thickness: 0.08 mm, tack: 4.4 N / 19 mm) from Nitto was adhered to the protective layer, and the bonding strength was measured through a tensile test using a peel strength tester (AND, MCT-2150 W). At this time, the tensile speed was set to 50 mm / min, and the tensile test distance was set to within a total of 200 mm. The bonding strength was calculated as the average strength over a 150 mm section starting from the 50 mm mark of the tensile test.

[0160] Qualitative scratch evaluation was performed by scratching the protective coating layer with a tissue or handkerchief and assessing the degree of peeling.

[0161]

[0162] When evaluating the tape test, it was confirmed that the protective layer of Example 1 did not peel off even when subjected to the tape test, whereas it was confirmed that the protective layer of Comparative Example 1 was damaged when the tape test was performed. In addition, in the qualitative evaluation of scratches, it was confirmed that the protective layer of Comparative Example 1 was damaged more than that of Example 1.

[0163] In addition, the bonding strength between the protective layer and the current collector was measured for the electrodes of Example 1 and Comparative Example 1. Regarding the bonding strength, Example 1 was measured to be approximately 157.44 mN / cm, but it was confirmed that for Comparative Example 1, the protective layer peeled off as soon as the tape was applied to measure the bonding strength, making it impossible to evaluate the strength.

[0164]

[0165] The present invention is not limited to the above embodiments and can be manufactured in various different forms, and those skilled in the art will understand that the invention can be implemented in other specific forms without changing the technical concept or essential features of the invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive.

Claims

1. Entire house; A metal layer comprising a lithium alloy alloyed with a lithium-friendly material and located on at least one surface of the above-mentioned current collector; and A protective layer disposed on the metal layer and comprising at least one of a carbonaceous material and a nitrogen-based and magnesium-based alloy, and A lithium metal electrode for a lithium secondary battery that does not include a peak value at 17 to 20° in the XRD peak value.

2. In Paragraph 1, A lithium metal electrode for a lithium secondary battery, wherein the bonding strength between the above-mentioned current collector and the above-mentioned protective layer is 140.0 mN / cm or more.

3. In Paragraph 1, A lithium metal electrode for a lithium secondary battery comprising a peak value at least one of 41 to 43° and 61 to 63° in the XRD peak value.

4. In Paragraph 1, A lithium metal electrode for a lithium secondary battery, wherein the content of the above nitrogen-based and magnesium-based alloys is 15 to 70 weight% based on 100 weight% of the protective layer.

5. In Paragraph 1, The above-mentioned lithium-friendly material is a lithium metal electrode for a lithium secondary battery comprising at least one of In, Ag, Sn, Zn, Si, Al, and Bi.

6. Entire house; A metal layer comprising a lithium-friendly material located on at least one surface of the above-mentioned current collector; and A protective layer disposed on the metal layer and comprising at least one of a carbonaceous material and a nitrogen-based and magnesium-based alloy, and A non-negative electrode for a lithium secondary battery that does not include a peak value at 17 to 20° in the XRD peak value.

7. The stage of preparing the entire house; A step of forming a coating layer on at least one surface of a current collector using a coating composition containing a lithium-friendly component; The method includes the step of forming a protective layer by coating a slurry onto the surface of the coating layer. The above slurry is a method for manufacturing a lithium metal electrode comprising a carbonaceous material, a metal nitride, and a non-aqueous solvent.

8. In Paragraph 7, The above-mentioned non-aqueous solvent is a method for manufacturing a lithium metal electrode comprising an organic solvent.

9. In Paragraph 7, A method for manufacturing a lithium metal electrode comprising at least one of the following: the above-mentioned non-aqueous solvent, NMP (N-Methyl-2-pyrrolidone), EG (Ethylene glycol), DMF (dimethylformamide), DMAC (Dimethylacetamide), DMSO (Dimethyl sulfoxide), THF (Tetrahydrofuran), Toluene, and Acetone.

10. In Paragraph 7, In the step of forming the above protective layer, A method for manufacturing a lithium metal electrode, wherein the content of the metal nitride is 5 to 80 weight% based on 100 weight% of the above slurry.

11. In Paragraph 7, A method for manufacturing a lithium metal electrode that further includes a binder in the step of forming the protective layer.

12. In Paragraph 11, The above binder is a non-aqueous binder, and A method for manufacturing a lithium metal electrode comprising at least one non-aqueous binder selected from PVDF (polyvinylidene fluoride), PVDF-HFP (polyvinylidene fluoride-hexafluoropropylene copolymer), PTFE (polytetrafluoroethylene), PAI (polyamideimide), PEO (polyethylene oxide), PANI (polyaniline), PDO (polypyrrole), and polythiophene.

Images