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

Abstract

The present invention relates to a lithium metal negative electrode and a method for manufacturing same. The lithium metal negative electrode of the present invention comprises: a current collector; a lithium metal thin film layer positioned on at least one surface of the current collector; and a film positioned on the surface of the lithium metal thin film layer, wherein the lithium metal thin film layer comprises organic layers disposed spaced apart from each other therewithin.

Description

Lithium metal anode for lithium secondary battery and method for manufacturing same

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

[0002] To reduce the cost and increase the energy density of secondary batteries, the use of lithium metal anodes is essential. Specifically, all-solid-state batteries are attracting attention as next-generation batteries for high-energy densities, such as those required for electric vehicles (EVs).

[0003] All-solid-state batteries offer numerous advantages, including superior stability and high-voltage operation due to the elimination of liquid electrolytes. Furthermore, they reduce the need for cooling and safety-related components, resulting in higher energy density within the battery pack. Furthermore, they operate over a wide temperature range. To achieve truly high energy densities in these all-solid-state batteries, thick, low-capacity graphite-based anodes must be replaced with thin, high-capacity lithium. Considering cost-effectiveness and energy density, a thin-film lithium metal anode with a thickness of 10 to 20 μm is practically required.

[0004] Typically, lithium metal anodes face challenges in manufacturing thin layers of lithium metal through commercial processes. Furthermore, dendrite growth, caused by uneven current density and electrochemical reactions during the charging and discharging of secondary batteries, poses a challenge. This can lead to persistent side reactions with the electrolyte and even internal short circuits where the anode and cathode contact each other. This dendrite growth can also cause significant problems, including poor cycle life and stability.

[0005] While various methods have been proposed to inhibit dendrite growth and extend battery life, achieving both high energy density through ultra-thin lithium and sufficient battery life remains challenging. Therefore, there is an urgent need to develop technology that utilizes lithium metal anodes to enhance the energy density of lithium secondary batteries while simultaneously achieving superior charge / discharge characteristics and reproducibility.

[0006] According to one technical embodiment of the present invention, a lithium metal anode for a lithium secondary battery improves lithium ion conductivity to increase the lithium stacking speed and provides a lithium secondary battery having improved charge / discharge life characteristics.

[0007] According to another embodiment of the present invention, a method for manufacturing a lithium metal anode for a lithium secondary battery provides a method for manufacturing a lithium metal anode for a lithium secondary battery having the advantages described above.

[0008] According to one embodiment of the present invention, a lithium metal negative electrode includes a current collector, a lithium metal thin film layer positioned on at least one surface of the current collector, and a film positioned on a surface of the lithium metal thin film layer, and includes an organic layer spaced apart from and disposed within the lithium metal thin film layer, and the ratio of the N component of the EDAX value of the organic layer can satisfy 3 to 15.

[0009] (In the line analysis results for the N component of the above organic layer EDAX value, it refers to the ratio of (average of 5 peak values) / (average of 4 lowest values ​​between each peak))

[0010] In one embodiment, the ratio of the F component of the organic layer EDAX value can be satisfied from 3 to 15.

[0011] (In the line analysis results for the F component of the above organic layer EDAX value, it refers to the ratio of (average of 5 peak values) / (average of 4 lowest values ​​between each peak))

[0012] In one embodiment, the organic layer may include a Li-NCHO-based ionic compound. In one embodiment, the lithium metal thin film layer may have a flat surface microstructure without dendritic protrusions and may include a columnar structure extending upward from the current collector.

[0013] In one embodiment, the organic layer may be disposed at the interface of the columnar structure. In one embodiment, the columnar structure may satisfy a ratio of the major axis to the minor axis of 1.2 to 3.0.

[0014] According to another embodiment of the present invention, a method for manufacturing a lithium metal negative electrode includes the steps of electrically insulating a current collector and a lithium source in a plating solution and then stacking them while restraining them in both directions, and the step of simultaneously forming a metal thin film layer and a film on at least one surface of the current collector by applying a current in multiple stages between the current collector and the lithium source, wherein the temperature of the plating solution may be 10 to 50°C.

[0015] In one embodiment, the step of applying multiple currents between the current collector and the lithium source to simultaneously form a metal thin film layer and a film on at least one surface of the current collector may include a preliminary electrodeposition step and a main electrodeposition step applying a higher current than the preliminary electrodeposition step. In one embodiment, the preliminary electrodeposition step may include a first electrodeposition step and a second electrodeposition step applying different currents.

[0016] In one embodiment, the first electrodeposition step is 0.48 mA / cm 2 The following currents can be applied. In one embodiment, the second electrodeposition step is 0.3 to 1.0 mA / cm 2 A current of 0.8 to 10.0 mA / cm can be applied. In one embodiment, the electrodeposition step 2 A current of can be applied.

[0017] In one embodiment, the plating solution may include a nitrogen-based compound. In one embodiment, the nitrogen-based compound may include:

[0018] It may be at least one selected from the group consisting of lithium nitrate, lithium bis fluorosulfonyl imide, lithium bis trifluoromethane sulfonimide, caprolactam, N-methyl-caprolactam, triethylamine, and tributylamine. In one embodiment, the plating solution may include the nitrogen-based compound in a range of 1 wt% to 100 wt% based on 100 wt% of the plating solution.

[0019] According to one embodiment of the present invention, a lithium metal anode for a lithium secondary battery includes a lithium metal thin film layer and a film positioned on at least one surface of the lithium metal thin film layer, thereby providing a homogeneous interface, improving lithium ion conductivity, increasing a lithium stacking speed, and providing a lithium secondary battery with improved charge / discharge life characteristics.

[0020] According to another embodiment of the present invention, a method for manufacturing a lithium metal anode for a lithium secondary battery provides a method for manufacturing a lithium metal anode having the above-described advantages.

[0021] Figures 1 and 2 schematically illustrate a lithium metal negative electrode according to one embodiment, respectively.

[0022] Figures 3 and 4 schematically illustrate a manufacturing process of a lithium metal negative electrode according to one embodiment, respectively.

[0023] FIG. 5 is a microstructure photograph of a lithium metal negative electrode according to one embodiment of the present invention.

[0024] Figure 6 is a diagram for calculating the ratio of the EDAX peak value of the film layer of the present invention.

[0025] The terms first, second, and third, etc., are used to describe, but are not limited to, various parts, components, regions, layers, and / or sections. These terms are used only to distinguish one part, component, region, layer, or section from another part, component, region, layer, or section. Accordingly, a first part, component, region, layer, or section described below may be referred to as a second part, component, region, layer, or section without departing from the scope of the present invention.

[0026] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the present invention. As used herein, the singular forms "singular" and "comprising" include plural forms as well, unless the context clearly dictates otherwise. The word "comprising" as used herein specifies a particular feature, region, integer, step, operation, element, and / or component, but does not exclude the presence or addition of other features, regions, integers, steps, operations, elements, and / or components.

[0027] When a part is referred to as being "on" or "over" another part, it can be directly on or over the other part, or there may be other parts intervening. Conversely, when a part is referred to as being "directly on" another part, there are no other parts intervening.

[0028] Although not defined otherwise, all terms, including technical and scientific terms, used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention pertains. Terms defined in commonly used dictionaries are further interpreted to have meanings consistent with the relevant technical literature and the present disclosure, and are not to be construed as ideal or overly formal unless otherwise defined.

[0029] Figure 1 schematically illustrates a lithium metal negative electrode according to one embodiment.

[0030] Referring to FIG. 1, a lithium metal negative electrode (10) according to one embodiment includes a current collector (11), a lithium metal thin film layer (12), and a film (13). Specifically, the lithium metal negative electrode (10) according to this embodiment includes a lithium metal thin film layer (12) positioned on both sides of the current collector (11), and a film (13) positioned on each surface of the lithium metal thin film layer (12). More specifically, the lithium metal negative electrode (10) includes an organic layer (14) spaced apart from each other and disposed within the lithium metal thin film layer (12).

[0031] The current collector (11) is for electrical connection within the battery. The current collector (11) may have a form of a foil, but is not limited thereto, and may have, for example, a form of a mesh, foam, rod, wire, or sheet made by weaving wire (fiber).

[0032] As a material for the current collector (11), a material that has electrical conductivity and has limited reaction with lithium can be used. As a material for the current collector (11), for example, any one or a combination of copper, nickel, titanium, stainless steel, iron, gold, platinum, silver, tantalum, ruthenium, and alloys thereof, carbon, conductive polymers, and composite fibers coated with a conductive layer on a non-conductive polymer can be used.

[0033] If the current collector (11) is thick, the battery weight increases and the energy density of the battery decreases. If the current collector (11) is thin, there is a risk of overheating and damage during high current operation, and the battery may be damaged by tension during the battery manufacturing process. Therefore, the thickness of the current collector (11) may be in the range of 1 ㎛ to 50 ㎛.

[0034] A lithium metal thin film layer (12) may be positioned on at least one surface of the collector (11).

[0035] The above lithium metal thin film layer (12) is characterized by having a smooth and dense surface microstructure without dendrites and including a columnar structure extending upward from the current collector (11).

[0036] In the present invention, the columnar structure (12C) included in the lithium metal thin film layer (12) can be implemented by forming the lithium metal thin film layer (12) using an electrochemical plating method using a plating solution containing appropriate components. The average diameter of the columnar structure (12C) can be in the range of 0.1 µm to 100 µm, and more specifically, 5 µm to 40 µm.

[0037] If the average diameter of the columnar structure (12C) is 0.1 ㎛ or more, the surface uniformity of the lithium metal thin film layer (12) is excellent, so that when the lithium metal negative electrode according to the embodiment is applied to a battery, a lithium secondary battery having excellent electrochemical characteristics can be realized. If the average diameter of the columnar structure (12C) is 100 ㎛ or less, the time required for the formation process of the lithium metal thin film layer (12) can be reduced, thus improving productivity.

[0038] This is because the average diameter of the columnar grain structure (12C) can be controlled by controlling the conditions of the electrodeposition process. For example, if the current density is lowered during the electrodeposition process, the average diameter of the columnar grain structure (12C) increases, and if the current density is increased, the average diameter of the columnar grain structure decreases. If the current density is lowered to increase the average diameter of the columnar grain structure (12C), the time required for the lithium metal thin film layer (12) formation process increases. In the present specification, the average diameter of the columnar grain structure (12C) can be measured using the method of ASTM E 112 for the surface microstructure of the lithium metal negative electrode (10).

[0039] In one embodiment, the columnar structure (12C) can satisfy a ratio of the major axis to the minor axis of 1.5 to 5. Specifically, the columnar structure (12C) can satisfy a ratio of the major axis to the minor axis of 1.5 to 2.5. Since the ratio of the major axis to the minor axis of the columnar structure (12C) satisfies the aforementioned range, the area of ​​the grain boundary is reduced, which has the advantage of reducing the area of ​​the side reaction with the electrolyte during charge and discharge.

[0040] The columnar structure (12C) has a problem in that if the ratio of the major axis to the minor axis exceeds the upper limit of the aforementioned range, it is close to a dendrite shape, which causes additional dendrite growth and lithium loss during the charge / discharge process. If the ratio of the major axis to the minor axis exceeds the lower limit of the aforementioned range, the columnar structure (12C) has a problem in that the interfacial area of ​​the particles increases, which increases side reactions with the electrolyte.

[0041] In one embodiment, the columnar structure (12C) can satisfy an average width gap value of 1 to 20 μm. Specifically, the columnar structure (12C) can satisfy an average width gap value of 5 to 10 μm. Since the average width gap value of the columnar structure (12C) satisfies the above-described range, there is an advantage in that the area of ​​the particle interface is appropriately maintained, thereby minimizing side reactions with the electrolyte during charge and discharge.

[0042] If the average width gap value exceeds the upper limit of the aforementioned range, the area of ​​the organic layer (14) that has excellent ionic conductivity and acts as a protective film decreases, which causes a problem of reduced charge / discharge performance. If the average width gap value exceeds the lower limit of the aforementioned range, the particle size becomes very small, which causes a problem of increased side reactions with the electrolyte, as the grain boundary area increases significantly.

[0043] The average porosity of the lithium metal thin film layer (12) may be 0.1% to 10%, more specifically 1% to 5%. When the average porosity of the lithium metal thin film layer (12) exceeds 10%, the lithium metal thin film layer (12) has a porous microstructure. In this case, when the lithium metal negative electrode according to the embodiment is applied to a lithium secondary battery, the desorption and attachment of lithium from the lithium metal negative electrode (10) may occur unevenly during charge and discharge, which may promote dendrite growth, and there is a problem that the battery capacity and charge and discharge lifespan may be reduced due to dendrite short circuit (dead lithium), etc. In addition, when the lithium metal thin film layer (12) is manufactured with a low average porosity of 0.1% or less, the time required for the formation process of the lithium metal thin film layer (12) according to the embodiment increases, thereby reducing productivity.

[0044] Next, the thickness of the lithium metal thin film layer (12) may be in the range of 0.1 μm to 200 μm, more specifically, 0.1 μm to 30 μm. If the thickness of the lithium metal thin film layer (12) is thick, when the lithium metal negative electrode according to the embodiment is applied to a lithium secondary battery, there is a problem that the weight of the battery increases and the energy density decreases. In addition, since the manufacturing time and cost increase in proportion to the thickness when forming the lithium metal thin film layer (12), the thickness of the lithium metal thin film layer (12) is preferably 200 μm or less.

[0045] If the thickness of the lithium metal thin film layer (12) is too thin, when the lithium metal negative electrode according to the embodiment is applied to a lithium secondary battery, there is a problem that the charge / discharge life of the battery is reduced. Specifically, during charge / discharge of the battery, lithium in the battery is gradually consumed due to side reactions between the lithium contained in the active material and the electrolyte, etc., and the battery capacity is reduced. However, if the thickness of the lithium metal thin film layer (12) is thin, the amount of lithium that can replenish the consumed lithium during charge / discharge is reduced, and thus the charge / discharge life of the battery is reduced. Therefore, the thickness of the lithium metal thin film layer (12) is preferably 0.1 ㎛ or more.

[0046] The thickness of this lithium metal thin film layer (12) can be easily controlled by adjusting the electrodeposition process conditions such as current density and electrodeposition time in the lithium metal thin film layer (12) formation process using an electrochemical plating method.

[0047] The lithium metal negative electrode (10) includes a film (13) located on the surface of a lithium metal thin film layer (12). The film (13) is formed during the manufacturing process of the lithium metal thin film layer (12) by a reaction between the electrodeposited lithium metal and the plating solution, etc., and the thickness, composition, and characteristics of the film (13) can be controlled by adjusting the composition of the plating solution used and the conditions of the electrodeposition process.

[0048] The thickness of the film (13) may be, for example, in the range of 2 nm to 2 μm, more specifically, 10 nm to 500 nm. If the thickness of the film (13) located on the surface of the lithium metal thin film layer (12) is too thick, the lithium ion conductivity may decrease and the interface resistance may increase, which may deteriorate the charge / discharge characteristics when applied to a battery. In addition, if the thickness of the film (13) is too thin, the film (13) may be easily lost during the process of applying the lithium metal negative electrode according to the embodiment to a battery. Therefore, it is preferable that the film (13) be uniformly and densely formed on the entire surface of the lithium metal thin film layer (12) with a thin thickness within the range satisfying the above thickness range.

[0049] In one embodiment, the organic layer (14) may be spaced apart and disposed within the lithium metal thin film layer (12). Specifically, the organic layer (14) may be disposed between the columnar structures (12C) within the lithium metal thin film layer (12). More specifically, the organic layer (14) may be disposed at the interface between the columnar structures (12C).

[0050] In one embodiment, the organic layer (14) and the film (13) may be composed of the same material. Specifically, the organic layer (14) may be formed by the film (13) disposed on the surface during the lithium electrodeposition process described below being also disposed at the interface of the columnar structure (12C).

[0051] The lateral width of the organic layer (14) may be in the range of 2 nm to 2 μm, more specifically, 100 nm to 1 μm. The lateral width of the organic layer (14) has the advantage of being able to secure ion conductivity while serving as a protective layer for lithium particles by satisfying the aforementioned range of the columnar structure (12C). If the lateral width of the organic layer (14) is too thick, the lithium ion conductivity may decrease and the interfacial resistance may increase, which may deteriorate the charge / discharge characteristics when applied to a battery. In addition, if the lateral width of the organic layer (14) is too thin, it may be easily lost or may not serve as a protective layer during the process of applying the lithium metal negative electrode according to the embodiment to a battery.

[0052] In one embodiment, the ratio of the N component of the EDAX value of the organic layer (14) can satisfy 3 to 15. The ratio of the N component of the EDAX value of the organic layer (14) can satisfy 5 to 12.

[0053] In one embodiment, the ratio of the F component of the EDAX value of the organic layer (14) can satisfy 3 to 15. The ratio of the F component of the EDAX value of the organic layer (14) can satisfy 4 to 10.

[0054] When the ratio of the N component and the ratio of the F component of the EDAX value of the organic layer (14) satisfy the above-mentioned range, it can be confirmed that the organic layer (14) remains at the interface of the columnar structure within the electrode. In addition, when the ratio of the N component and the ratio of the F component of the EDAX value of the organic layer (14) satisfy the above-mentioned range, the charge / discharge performance of the electrode can be improved by arranging the organic layer (14) between the columnar structure interfaces. In contrast, when the ratio of the N component and the ratio of the F component of the EDAX value of the organic layer (14) exceeds the lower limit of the above-mentioned range, it is determined that the organic layer (14) is not included at the interface of the columnar structure, and there is a problem that the charge / discharge performance of the electrode is inferior.

[0055] In one embodiment, the film (13) and the organic layer (14) include a Li-NCHO-based ionic compound. In this embodiment, in the process of manufacturing a lithium metal thin film layer (12) by an electrodeposition process, the film (13) and the organic layer (14) including the Li-NCHO-based ionic compound can be formed by controlling the composition and content of the plating solution.

[0056] The Li-NCHO-based ionic compound may include Li-O, CN, CO, and CH bonds. Specifically, the Li-NCHO-based ionic compound may include a compound represented by any one of the following chemical formulas 1 to 2.

[0057] [Chemical Formula 1]

[0058]

[0059] In chemical formula 1, R1 and R2 are each CH m F 2-m (m=0, 1, 2),

[0060] A1 is or and,

[0061] n1 is an integer from 1 to 10.

[0062] [Chemical Formula 2]

[0063]

[0064] In chemical formula 2, R3 and R4 are each CH m F 2-m (m=0, 1, 2),

[0065] A2 is or and,

[0066] n2 is an integer from 1 to 10.

[0067] More specifically, the compound represented by the above chemical formula 1 may be at least one of the compounds represented by the following chemical formulas 1-1 and 1-2.

[0068] The compound represented by the above chemical formula 2 may be at least one of the compounds represented by the following chemical formulas 2-1 and 2-2.

[0069] [Chemical Formula 1-1]

[0070]

[0071] In chemical formula 1-1, n3 is an integer from 1 to 5.

[0072] Specifically, for example, when a lithium metal thin film layer (12) is formed through an electrodeposition process using a plating solution in which lithium nitrate (LiNO3) is used as a nitrogen-based compound and an appropriate amount of this is added to an ether-based solvent, a film (13) including a compound represented by the chemical formula 1-1 is formed on the surface of the lithium metal thin film layer (12), and an organic layer (14) can be formed between columnar structures (12C) within the lithium metal thin film layer (12).

[0073] [Chemical Formula 1-2]

[0074]

[0075] In chemical formula 1-2, R5 and R6 are each CH m F2-m (m=0, 1, 2), and n4 is an integer from 1 to 5.

[0076] Specifically, for example, when a lithium metal thin film layer (12) is formed through an electrodeposition process using lithium bis fluorosulfonyl imide (LiN(FSO2)2) as a nitrogen-based compound and a plating solution containing an appropriate amount of lithium bis fluorosulfonyl imide added to an ether-based solvent, a film (13) including a compound represented by the chemical formula 1-2 is formed on the surface of the lithium metal thin film layer (12), and an organic layer (14) can be formed between columnar structures (12C) within the lithium metal thin film layer (12).

[0077] In the case where lithium bisfluorosulfonyl imide (LiN(FSO2)2) is used as a nitrogen-based compound included in the plating solution, due to the fluorine (F) component included therein, some of the CH bonds of the -CH2- structure of the Li-NCHO-based ionic compound of the film (13) are replaced with CF bonds, as in Chemical Formula 1-2, -CH m F 2-m - (m=0, 1, 2) can have a structure.

[0078] [Chemical Formula 2-1]

[0079]

[0080] In chemical formula 2-1, n5 is an integer from 1 to 5.

[0081] Specifically, for example, when a lithium metal thin film layer (12) is formed through an electrodeposition process using a plating solution in which lithium nitrate is used as a nitrogen-based compound and an appropriate amount of the same is added to a carbonate-based solvent, a film (13) including a compound represented by the chemical formula 2-1 is formed on the surface of the lithium metal thin film layer (12), and an organic layer (14) can be formed between columnar structures (12C) within the lithium metal thin film layer (12).

[0082] [Chemical Formula 2-2]

[0083]

[0084] In chemical formula 2-2, R7 and R8 are each CH m F 2-m (m=0, 1, 2), and n6 is an integer from 1 to 5.

[0085] More specifically, for example, when a lithium metal thin film layer (12) is formed through an electrodeposition process using a plating solution in which lithium bisfluorosulfonyl imide is used as a nitrogen-based compound and an appropriate amount of this is added to a carbonate-based solvent, a film (13) including a compound represented by Chemical Formula 2-2 can be formed on the surface of the lithium metal thin film layer (12).

[0086] In the case where lithium bisfluorosulfonyl imide (LiN(FSO2)2) is used as a nitrogen-based compound included in the plating solution, due to the fluorine (F) component included therein, some of the CH bonds of the -CH2- structure of the Li-NCHO-based ionic compound of the film (13) are replaced with CF bonds, as in Chemical Formula 2-2, -CH m F 2-m - (m=0, 1, 2) can have a structure.

[0087] That is, in the present embodiment, by controlling the type and content of the nitrogen-based compound and solvent included in the plating solution in the process of forming the lithium metal thin film layer (12), it is possible to implement a film (13) including at least one compound among the compounds represented by the chemical formulas 1 and 2 so as to be positioned on the surface of the lithium metal thin film layer (12).

[0088] Meanwhile, the film (13) and the organic layer (14) may further include LiF in addition to the Li-NCHO-based ionic compound. Specifically, for example, when lithium bisfluorosulfonyl imide (LiN(FSO2)2) is used as the nitrogen-based compound included in the plating solution, the film (13) and the organic layer (14) may further include LiF in addition to the Li-NCHO-based ionic compound due to the fluorine (F) component included therein.

[0089] In addition, even when a fluorine-based compound such as fluoroethylene carbonate (FEC) is further included in the plating solution, the film (13) and the organic layer (14) may include LiF together with a Li-NCHO-based ionic compound.

[0090] In this way, when the film (13) and the organic layer (14) further contain LiF, the electrochemical performance of the film (13) and the organic layer (14) can be further improved through interaction with the Li-NCHO-based ionic compound.

[0091] As in the present embodiment, when a lithium metal anode (10) including a film (13) and an organic layer (14) including a Li-NCHO-based ionic compound is applied to a lithium secondary battery, side reactions between the electrolyte and the lithium metal thin film layer (12) can be blocked. In addition, by uniformly desorption and attachment of lithium on the surface of the lithium metal thin film layer (12) and suppressing dendrite growth, the charge / discharge life of the lithium secondary battery can be improved.

[0092] In addition, it is possible to prevent defects from occurring in subsequent processes such as packaging, transportation, storage, and application of the lithium metal negative electrode (10) of the present embodiment to a battery. Since the lithium metal negative electrode (10) according to the present embodiment includes a film (13) positioned on the surface of the lithium metal thin film layer (12) and an organic layer (14) disposed between the columnar structures (12C) in the lithium metal thin film layer (12), it is possible to block the reaction of the lithium metal thin film layer (12) with moisture and / or oxygen, etc. in the aforementioned subsequent process, and thus it is possible to very effectively prevent the formation of an uneven surface reaction layer (Native surface film) on the surface of the lithium metal thin film layer (12).

[0093] FIG. 2 schematically illustrates a lithium metal negative electrode for a secondary battery according to another embodiment.

[0094] Referring to FIG. 2, a lithium metal negative electrode (10) according to the present embodiment includes a current collector (11), a lithium metal thin film layer (12) located on one surface of the current collector (11), a film (13) located on the surface of the lithium metal thin film layer (12), and an organic layer (14) spaced apart and arranged within the lithium metal thin film layer (12).

[0095] The description of the current collector (11), lithium metal thin film layer (12), film (13), and organic layer (14) of this embodiment is the same as that described in the previous embodiment with reference to FIG. 1. Therefore, a detailed description of the same or similar components is omitted.

[0096]

[0097] Next, a method for manufacturing a lithium metal negative electrode according to one embodiment of the present invention will be described.

[0098] A method for manufacturing a lithium metal negative electrode according to one embodiment includes the steps of electrically insulating a current collector and a lithium source in a plating solution and then stacking them while restraining them from both directions, and the step of applying a current between the current collector and the lithium source to simultaneously form a metal thin film layer, a film, and an organic layer on at least one surface of the current collector.

[0099] FIG. 3 schematically illustrates a manufacturing process of a lithium metal negative electrode (10) for a secondary battery according to one embodiment of the present invention.

[0100] Referring to Fig. 3, a current collector (11) and a lithium supply source (20) on which a lithium metal thin film layer is to be laminated are placed in a plating solution (30) for electrodeposition.

[0101] The lithium supply source (20) may be, for example, lithium metal, a lithium alloy, a foil obtained by pressing the lithium metal or lithium alloy onto a current collector, etc. The current collector (11) is the same as that described above, and reference may be made to the contents of Fig. 1.

[0102] The plating solution (30) can be prepared by dissolving a lithium salt in a non-aqueous solvent. Specifically, the plating solution (30) is characterized in that at least one of the lithium salt and the non-aqueous solvent contains a nitrogen-based compound.

[0103] The nitrogen compound may include, for example, at least one selected from the group consisting of lithium nitrate, lithium bis fluorosulfonyl imide, lithium bis trifluoromethane sulfonimide, e-Caprolactam, N-methyl-e-caprolactam, triethylamine, and tributylamine.

[0104] Among the above nitrogen compounds, at least one of lithium nitrate, lithium bis fluorosulfonyl imide, and lithium bis trifluoromethane sulfonimide can be used as a lithium salt.

[0105] At least one of caprolactam (e-Caprolactam), methyl caprolactam (N-methyl-e-caprolactam), triethylamine, and tributylamine can be used as a non-aqueous solvent.

[0106] The plating solution (30) may contain the nitrogen-based compound in an amount ranging from 1 wt% to 100 wt%, more specifically from 5 wt% to 90 wt%, from 5 wt% to 70 wt%, or from 5 wt% to 60 wt%, based on 100 wt% of the plating solution.

[0107] When the content of the above nitrogen compound is less than 1 wt%, there is a problem in that the Li-NCHO ionic compound is not properly formed in the film (13).

[0108] Meanwhile, the plating solution (30) can be manufactured using only the nitrogen-based compound, but a general non-aqueous solvent can be added as an auxiliary solvent in consideration of the viscosity of the plating solution, etc. If the viscosity of the plating solution is too high, the mobility of lithium ions decreases, which lowers the ionic conductivity of the plating solution, thus increasing the time required for the formation process of the metal thin film layer (12), thereby reducing productivity.

[0109] The auxiliary solvent may include, for example, at least one 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.

[0110] The auxiliary solvent for controlling the viscosity of the plating solution may be included in an amount of 5 wt% to 70 wt%, more specifically, 10 wt% to 60 wt%, based on 100 wt% of the plating solution.

[0111] In one embodiment, the plating solution (30) may further include a fluorine-based compound. The fluorine-based compounds include, for example, lithium difluoro phosphate, lithium hexafluoro phosphate, lithium difluoro bisoxalato phosphate, lithium tetrafluoro oxalato phosphate, lithium difluoro oxalate borate, lithium difluoro oxalato borate, lithium tetrafluoro oxalato borate, fluoroethylene carbonate, difluoroethylene carbonate, and 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether. It may include at least one selected from the group consisting of 2,2,3,3-Tetrafluoropropyl ether.

[0112] The plating solution (30) may contain the fluorine-based compound in an amount ranging from 0.1 wt% to 30 wt%, more specifically, from 1 wt% to 10 wt%, based on 100 wt% of the plating solution.

[0113] When the content of the fluorine-based compound is less than 0.1 wt%, the interaction between the nitrogen-based compound and the fluorine-based compound in the plating solution does not occur smoothly, so there is a problem that the effect of improving the properties of the film (13) and the organic layer (14) of the lithium metal negative electrode (10) being manufactured is not exhibited. When the content of the fluorine-based compound exceeds 30 wt%, there is a problem that the electrochemical properties of the film (13) being manufactured are deteriorated, because excessive generation of LiF due to the direct reaction between the fluorine-based compound and lithium occurs.

[0114] Next, after positioning an insulating film (40) between the current collector (11) and the lithium supply source (20), the current collector (11), the lithium supply source (20), and the insulating film (40) are laminated and restrained in both directions using a restraining device (50).

[0115] At this time, the restraint device (50) can use a method generally used in the relevant technical field, such as a manual clamping method, a single-axis pressurization method using hydraulics, pneumatics, etc., and is not particularly limited.

[0116] In addition, the insulating film (40) can use a separator material used in a lithium secondary battery, and is not particularly limited.

[0117] After configuring the electrodeposition equipment in this manner, a film (13) and a lithium metal thin film layer (12) are formed on the surface of the current collector (11) by applying current to the current collector (11) and the lithium supply source (20) using a power supply device (60). At this time, the current collector (11) is connected to the (-) electrode, and the lithium supply source (20) is connected to the (+) electrode.

[0118] The step of forming a lithium metal thin film layer and film on at least one surface of the current collector (11) is performed by applying current between the current collector (11) and a lithium supply source (20).

[0119] The applied current is an average current density of 0.1 mA / cm based on the collector area. 2100mA / cm 2 range, more specifically 0.5mA / cm 2 20mA / cm 2 This can be within the range. As the current density increases, the deposition rate of the lithium metal thin film increases, thereby increasing productivity. However, this can lead to a decrease in the film properties, which can lower the performance of the manufactured lithium metal anode. Therefore, the current density is preferably within the above range.

[0120] By applying current in this manner, lithium moved from a lithium source (20) is deposited on the surface of a current collector (11), thereby forming a lithium metal thin film layer (12). At this time, the thickness of the lithium metal thin film can be easily controlled by controlling current density, deposition time, and deposition process conditions.

[0121] In addition, a film (13) and an organic layer (14) can be formed by utilizing a reduction and decomposition reaction of a plating solution (30) on the surface of a current collector (11) and a reaction between a deposited lithium metal thin film layer and the plating solution (30). At this time, the thickness, composition, characteristics, etc. of the film produced can be controlled by adjusting the composition of the plating solution (30) used and the conditions of the electrodeposition process.

[0122] That is, the method for manufacturing a lithium metal negative electrode according to the embodiments is characterized by simultaneously forming a lithium metal thin film layer (12), a film (13), and an organic layer (14) including an electrodeposition step using an electrochemical plating method, an electrodeposition process.

[0123] More specifically, the electrodeposition step is a process at room temperature and pressure (e.g., 30° C. or less, 1 atm) in which lithium ions are supplied from a lithium source and a lithium metal thin film layer (12) is electrochemically deposited on the surface of a current collector (11). Additionally, the temperature of the electrodeposition process may be increased to improve the deposition speed of the lithium metal thin film layer (12) or to facilitate the formation of the film (13) and the organic layer (14).

[0124] When using an electrochemical plating method as described above, a lithium metal anode can be manufactured economically, large-area lamination is easy, and thickness control of the lithium metal thin film layer is also very easy. Furthermore, during the manufacturing process, a film having a specific component as described above can be controlled to be uniformly and densely formed on the surface of the lithium metal thin film layer. Therefore, when a lithium metal anode manufactured by the method according to the present embodiment is applied to a lithium secondary battery, a lithium secondary battery with excellent electrochemical performance can be realized.

[0125] In one embodiment, the electrodeposition step may include a multi-stage electrodeposition step. Specifically, the multi-stage electrodeposition step may mean a step performed multiple times at different current densities.

[0126] In one embodiment, the multi-stage electrodeposition step may include a preliminary electrodeposition step and a main electrodeposition step. The preliminary electrodeposition step may include a low-current electrodeposition section at the beginning of lithium electrodeposition. The main electrodeposition step may be an electrodeposition step performed subsequent to the preliminary electrodeposition step, and may be a step in which lithium is deposited at a higher current than the preliminary electrodeposition step.

[0127] Specifically, the preliminary electrodeposition step may be a step in which electrodeposition is performed at a low current in the initial stage of lithium electrodeposition. The preliminary electrodeposition step may be performed at 1 mA / cm 2 It may be a step of maintaining the current in a range lower than the current of the electrode. By including the above preliminary electrodeposition step, the decomposition of the additive contained in the plating solution can be promoted, thereby improving the charge / discharge performance of the electrode.

[0128] In one embodiment, the present electrodeposition step is an electrodeposition step performed after the preliminary electrodeposition step, and is performed at 0.8 to 10.0 mA / cm 2 can be performed under a current of 0.9 to 5.0 mA / cm. Specifically, the above electrodeposition step 2, more specifically, 1.0 to 4.0 mA / cm 2 can be performed under a current density of .

[0129] In one embodiment, the pre-electrodeposition step may include a first electrodeposition step and a second electrodeposition step. Specifically, the pre-electrodeposition step may be performed multiple times under multiple different current densities. More specifically, the first electrodeposition step may be performed at a lower current density than the second electrodeposition step.

[0130] In one embodiment, the first electrodeposition step is 0.48 mA / cm 2 It can be performed under the following current. Specifically, the first electrodeposition step is 0.4 mA / cm 2 Hereinafter, more specifically, 0.05 to 0.4 mA / cm 2 , more specifically, 0.1 to 0.3 mA / cm 2 It can be performed under a current density of . As the first electrodeposition step is performed within the above-mentioned range, the decomposition of the additive in the plating solution can be facilitated, and the formation of the film (13) and the organic layer (14) can be easily controlled, thereby improving the charge / discharge performance of the electrode.

[0131] In one embodiment, the second electrodeposition step is 0.3 to 1.0 mA / cm 2 can be performed under a current of 0.4 to 0.9 mA / cm. Specifically, the first electrodeposition step 2 , more specifically, 0.45 to 0.75 mA / cm 2 , more specifically, 0.45 to 0.55 mA / cm 2 It can be performed under a current density of . As the second electrodeposition step is performed within the above-mentioned range, the decomposition of the additive in the plating solution can be facilitated, and the formation of the film (13) and the organic layer (14) can be easily controlled, thereby improving the charge / discharge performance of the electrode.

[0132] In one embodiment, the first electrodeposition step and the second electrodeposition step may be performed for a time period of from 10 minutes to 50 minutes, specifically, from 20 minutes to 40 minutes, and more specifically, from 25 minutes to 35 minutes.

[0133] In this way, the preliminary electrodeposition step can improve the charge / discharge performance of the electrode by more easily forming the film (13) and the organic layer (14) within the electrode by sequentially performing the first electrodeposition step and the second electrodeposition step with different currents.

[0134] In one embodiment, the electrodeposition step may be performed at a temperature of the plating solution in the range of 10 to 55° C. More specifically, the temperature may be performed at a temperature range of 15 to 50° C., more specifically, 20 to 45° C., and even more specifically, 25 to 40° C. By performing the temperature in the above-described range, not only the film (13) within the electrode but also the organic layer (14) can be easily formed, thereby improving the charge / discharge performance of the electrode.

[0135] Meanwhile, FIG. 3 illustrates a manufacturing process in which only one current collector (11) and one lithium supply source (20) are positioned, but multiple current collectors (11) may be present.

[0136] Figure 4 schematically illustrates a manufacturing process of a lithium metal negative electrode according to another embodiment.

[0137] Referring to FIG. 4, according to a manufacturing process of a lithium metal negative electrode according to another embodiment, a current collector (11) may be positioned on both sides of a lithium supply source (20) with an insulating film (40) interposed therebetween. The current collector (11) and the lithium supply source (20) are each connected to a power supply device (60) to receive current, and a lithium metal thin film layer is formed on the surface of both current collectors (11).

[0138] Likewise, by controlling the reduction and decomposition reaction of the plating solution (30) on the surface of the current collector (11) and the reaction between the deposited lithium metal thin film layer and the plating solution (30), a film having a desired composition and characteristics can be formed on the surface of the lithium metal thin film layer. The lithium metal negative electrode manufactured by the method according to the embodiments can be usefully used as an negative electrode of a lithium secondary battery.

[0139] In one embodiment, a lithium secondary battery may include an electrode assembly including a positive electrode including a positive active material, a negative electrode being a lithium metal negative electrode of the present invention, and a separator disposed between the positive electrode and the negative electrode. This electrode assembly may be wound or folded and accommodated in a battery case.

[0140] Thereafter, an electrolyte may be injected into the battery case and sealed to complete the secondary battery. At this time, the battery case may have a cylindrical, square, pouch-shaped, coin-shaped, etc. shape.

[0141] The positive electrode may include a positive electrode active material layer and a positive electrode current collector. The positive electrode active material layer may include, for example, a Li compound including 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-metallic element selected from the group consisting of O, F, S, P, and combinations thereof.

[0142] In one embodiment, a conductive material may be further added to the positive electrode active material layer. The conductive material may be, but is not limited to, carbon black, ultrafine graphite particles, fine carbon such as acetylene black, nano metal particle paste, etc.

[0143] The above-described positive electrode current collector serves to support the positive electrode active material layer. Examples of positive electrode current collectors that can be used include, but are not limited to, aluminum foil, nickel foil, or a combination thereof.

[0144] The electrolyte to be filled in the lithium secondary battery may be a non-aqueous electrolyte or a solid electrolyte. Specifically, the electrolyte may be a solid electrolyte. The 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 solid electrolyte may be, for example, a gel polymer electrolyte obtained by impregnating a polymer electrolyte such as polyethylene oxide or polyacrylonitrile with an electrolyte, or an inorganic solid electrolyte such as LiI or Li3N.

[0145] The separator may be any membrane commonly used in lithium secondary batteries, as it separates the positive and negative electrodes and provides a passage for lithium ions to move. Specifically, the separator may be one that has low resistance to ion movement of the electrolyte and excellent electrolyte moisture retention capacity. 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 non-woven fabric or a woven fabric. Meanwhile, when a solid electrolyte is used as the electrolyte, the solid electrolyte may also function as the separator.

[0146] Hereinafter, embodiments of the present invention will be described in detail. However, these are presented as examples, and the present invention is not limited thereto, and the present invention is defined only by the scope of the claims set forth below.

[0147]

[0148] <Experimental Example>

[0149] Manufacturing of cathodes for lithium secondary batteries

[0150] <Example 1>

[0151] <Manufacturing the entire house>

[0152] A copper foil current collector was prepared for use in the negative electrode of the lithium secondary battery of the present invention. Specifically, the current collector used was a copper foil having a thickness of approximately 15 μm.

[0153]

[0154] Lithium electrodeposition process

[0155] In order to form a lithium metal thin film layer on the surface of the current collector, a lithium source and a current collector in a plating solution were electrically insulated and laminated, and then a lithium metal plate having a purity of 99.9% or more and a thickness of 500 ㎛ was pressed onto a copper current collector (Cu Plate) using a power supply device, and current was applied using the lithium source and the current collector as (+) and (-) electrodes, respectively.

[0156] At this time, the current density of the process is 0.2 mA / cm for the first electrodeposition step among the preliminary electrodeposition steps. 2 , 30 min, second electrodeposition step 0.5 mA / cm 2 It was performed for 30 minutes, and then the third electrodeposition step was performed at 2.0 mA / cm 2 , a lithium metal thin film layer with a thickness of approximately 20 μm was manufactured by gradually increasing the current density in three stages for 110 minutes. At this time, the temperature of the plating solution was maintained at 25°C. In addition, at this time, the reduction and decomposition reaction of the plating solution on the surface of the current collector and the reaction between the electrodeposited lithium metal thin film layer and the plating solution were controlled to form a film on the surface of the lithium metal thin film layer.

[0157] At this time, the plating solution was prepared by adding lithium bis(fluorosulfonyl)imide and lithium nitrate, which are nitrogen compounds, in amounts of 40 wt% and 10 wt%, respectively, based on 100 wt% of the plating solution, to a 1,2-dimethoxyethane solvent, and adding fluoroethylene carbonate, which is a fluorine compound, in amounts of 10 wt% based on 100 wt% of the plating solution.

[0158]

[0159] <Example 2>

[0160] The same procedure as Example 1 was followed, except that the temperature of the plating solution was changed to 40°C in the deposition step.

[0161]

[0162] <Example 3>

[0163] The current density of the electrodeposition step was 1.0 mA / cm 2 Except for the changes, the same procedure as Example 1 was performed.

[0164]

[0165] <Example 4>

[0166] The current density of the electrodeposition step was 4.0 mA / cm 2 Except for the changes, the same procedure as Example 1 was performed.

[0167]

[0168] <Comparative Example 1>

[0169] In the deposition stage, instead of performing the deposition stages in multiple stages such as the preliminary and main deposition stages, 0.7 mA / cm 2 The same procedure as Example 1 was followed, except that lithium was electrodeposited for 350 minutes at a current density of .

[0170]

[0171] Comparative Example 2

[0172] The pre-deposition step was not performed by dividing it into the first and second deposition steps, but at 0.2 mA / cm 2 The electrodeposition process was performed as a single process for 60 minutes at a current density of 2.0 mA / cm 2 The same procedure as in Example 1 was followed, except that the electrodeposition step was performed for 118 minutes at a current density of .

[0173]

[0174] <Comparative Example 3>

[0175] The pre-deposition step was not performed by dividing it into the first and second deposition steps, but at 0.5 mA / cm 2 The electrodeposition process was performed as a single process for 60 minutes at a current density of 2.0 mA / cm 2 The same procedure as in Example 1 was followed, except that the electrodeposition step was performed for 109 minutes at a current density of .

[0176]

[0177] Comparative Example 4

[0178] The same procedure as Example 1 was followed, except that the temperature in the plating solution was set to 60°C.

[0179]

[0180]

[0181] All-solid-state battery manufacturing

[0182] Using the cathode manufactured according to the above-described example, an all-solid-state battery was fabricated, and its charge-discharge cycle life was evaluated. To evaluate the all-solid-state battery cell, a pressurized, dedicated evaluation cell from Terraleader, capable of maintaining an inert atmosphere, was used. For the fabrication of the all-solid-state battery cell, a sulfide-based argyrodite (Li6PS5Cl) solid electrolyte was used, and the electrolyte was in pellet form with a thickness of approximately 0.7 mm. To ensure a dense electrolyte, the cell was pressurized at a pressure of 370 MPa.

[0183] Lithium having a thickness of 0.5 mm was attached as a reference electrode on one side of the electrolyte, and the negative electrode manufactured according to the examples and comparative examples was attached on the opposite side. The reference electrode and the evaluation electrode were attached to the solid electrolyte at a pressure of 50 MPa, and during the charge and discharge evaluation, the pressure was applied to 16 MPa in a dedicated evaluation cell.

[0184]

[0185] <Evaluation example>

[0186] Table 1 below shows data on the main phase characteristics of lithium metal negative electrodes manufactured according to examples and comparative examples and the characteristics of organic layers spaced apart within a lithium metal thin film layer.

[0187] The above columnar features represent the ratio of the long axis / short axis of the columnar features, and the organic layer component analysis data is represented as the organic layer features, and the charge / discharge characteristics are represented when applied to a battery as an effect.

[0188] Columnar characteristics: The ratio of the major axis / minor axis of the columnar crystals was calculated by measuring the length of the minor axis and major axis of the columnar crystals using the ImageJ image program developed by the National Institute of Health (NIH) on the surface and cross-sectional microstructure images observed with a ZEISS GEMINI-500 scanning electron microscope. The length of the minor axis was calculated by measuring the length of the 50 ㎛ width, 50 ㎛ height, and 2500 ㎛ area of ​​the surface microstructure image. 2 The size of the lithium particles contained in the particle was defined as the average size, and the length of the major axis was defined as the average value by selecting 10 points using the formula (lithium layer thickness / number of particles) in the cross-sectional microstructure image. The ratio of the major axis / short axis of the columnar crystal was measured from the lengths of the minor axis and major axis above.

[0189] FIG. 5 is a microstructure photograph of a lithium metal negative electrode according to one embodiment of the present invention.

[0190] Referring to Fig. 5, the size of lithium particles can be confirmed from the surface microstructure of the lithium metal negative electrode, which indicates the length of the short axis of the columnar grains. In addition, from the cross-sectional microstructure, it can be confirmed that a single columnar grain has a thickness of approximately 20 ㎛, which indicates the length of the long axis of the columnar grains.

[0191] Organic layer characteristics: The presence or absence of an organic layer was confirmed by linear analysis of the cross-section of lithium metal. The components of the organic layer were analyzed using the AZTEC program of OXFORD, using the analysis signal received from the GEMINI-500 scanning electron microscope of ZEISS. Linear analysis was performed by scanning the cross-section of the lithium layer at a height of about 1 / 2 the thickness of the lithium layer in the horizontal direction at a distance of about 100 ㎛ and analyzing the corresponding components. The presence or absence of the organic layer was confirmed by linear analysis of the fluorine (F) component and nitrogen (N) component, which are the main components of the film layer formed by the decomposition of the plating solution additive. The EDAX peak ratio for each component was calculated as (average of 5 peak values) / (average of the 4 lowest values ​​between each peak).

[0192] Figure 6 is a diagram for calculating the ratio of the EDAX peak value of the film layer of the present invention.

[0193] Referring to Figure 6, the ratio of EDAX peak values ​​represents the average of the maximum values ​​of the peak values ​​for the five circled portions indicated above the peak values ​​to the average of the minimum values ​​for the four circled portions indicated below the peak values.

[0194] Charge / discharge performance number (cycles): The reference electrode and evaluation electrode were attached to the solid electrolyte at a pressure of 50 MPa, and the dedicated evaluation cell was pressurized at 16 MPa during the charge / discharge evaluation. The charge / discharge evaluation was performed at 2 mA / cm 2 Charge for 0.5 hours at constant current of 2 mA / cm 2A 0.5-hour discharge at constant current was defined as one cycle. The charge-discharge life was defined as the end of the life when a short circuit occurred between the reference electrode and the evaluation electrode during the charge-discharge process or when the voltage between the two electrodes exceeded 2 V.

[0195] Distinction method Condition Product characteristics Effect (charge / discharge performance) (times) Primary current (mA / cm) 2 )Secondary current (mA / cm) 2 ) 3rd current (mA / cm) 2 )Temperature (℃)Columnar ratio (major axis / minor axis)Organic layer EDAX peak ratio (F component)Organic layer EDAX peak ratio (N component)Example 10.20.52.0252.056350Example 20.20.52.0401.81012410Example 30.20.51.0252.578300Example 40.20.54.0251.545280Comparative example 10.7251.11.11.1120Comparative example 20.22.0252.0102150Comparative example 30.52.0251.5212160Comparative example 40.20.52.0601.01.21.2110

[0196] Looking at the above Table 1, when comparing Examples 1 to 4 in which the preliminary electrodeposition step and the main electrodeposition step were performed with Comparative Example 1, it was confirmed that the columnar ratio and the EDAX value of the organic layer were outside the range of the present invention, and the charge / discharge performance of the electrode was very inferior in Comparative Example 1. In addition, it was confirmed that Examples 1 to 4 in which the preliminary electrodeposition step was performed in multiple stages as the first electrodeposition step and the second electrodeposition step did not have the EDAX value of the organic layer satisfying the range of the present invention, and the charge / discharge performance was also inferior, compared to Comparative Examples 2 and 3 in which the preliminary electrodeposition step was not performed in multiple stages. Looking at Example 1 and Comparative Example 4, it was confirmed that Comparative Example 4 in which the temperature of the plating solution was excessively high did not have the columnar ratio and the EDAX value of the organic layer satisfying the range of the present invention, and the charge / discharge performance was excessively low.

[0197] The present invention is not limited to the above-described embodiments, but can be manufactured in a variety of different forms. Those skilled in the art will appreciate that the present invention can be implemented in other specific forms without altering the technical spirit or essential characteristics of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive.

Claims

1. Whole house; A lithium metal thin film layer positioned on at least one surface of the above collector; and A film comprising a film positioned on the surface of a lithium metal thin film layer, Including an organic layer spaced apart and arranged within the lithium metal thin film layer, A lithium metal negative electrode having a ratio of N components in the above organic layer EDAX value of 3 to 15. (In the line analysis results for the N component of the above organic layer EDAX value, it refers to the ratio of (average of 5 peak values) / (average of 4 lowest values ​​between each peak)) 2. In paragraph 1, A lithium metal negative electrode having a ratio of the F component of the above organic layer EDAX value of 3 to 15. (In the line analysis results for the F component of the above organic layer EDAX value, it refers to the ratio of (average of 5 peak values) / (average of 4 lowest values ​​between each peak)) 3. In paragraph 1, The above organic layer is a lithium metal negative electrode including a Li-NCHO type ionic compound.

4. In paragraph 1, The above lithium metal thin film layer, It has a flat surface microstructure without dendritic protrusions, A lithium metal negative electrode comprising a columnar structure extending upward from the above-described collector.

5. In paragraph 4, The above organic layer is a lithium metal negative electrode arranged at the interface of the above columnar structure.

6. In paragraph 4, The above columnar structure is a lithium metal negative electrode having a ratio of the major axis to the minor axis of 1.2 to 3.

0.

7. A step of electrically insulating the current collector and the lithium supply source within the plating solution and then restraining them from both directions and laminating them; Comprising a step of simultaneously forming a metal thin film layer and a film on at least one surface of the current collector by applying a current in multiple stages between the current collector and the lithium supply source, A method for manufacturing a lithium metal negative electrode, wherein the temperature of the plating solution is 10 to 50°C.

8. In paragraph 7, A method for manufacturing a lithium metal negative electrode, wherein the step of simultaneously forming a metal thin film layer and a film on at least one surface of the current collector by applying multiple currents between the current collector and the lithium supply source includes a preliminary electrodeposition step and a main electrodeposition step of applying a higher current than the preliminary electrodeposition step.

9. In paragraph 8, A method for manufacturing a lithium metal negative electrode, wherein the above preliminary electrodeposition step includes a first electrodeposition step and a second electrodeposition step applying different currents.

10. In paragraph 9, The first electrodeposition step is 0.48 mA / cm 2 A method for manufacturing a lithium metal negative electrode by applying the following current.

11. In paragraph 9, The second deposition step is 0.3 to 1.0 mA / cm 2 A method for manufacturing a lithium metal negative electrode by applying a current.

12. In paragraph 8, The above electrodeposition step is 0.8 to 10.0 mA / cm 2 A method for manufacturing a lithium metal negative electrode by applying a current.

13. In paragraph 7, The above plating solution is a method for manufacturing a lithium metal negative electrode including a nitrogen-based compound.

14. In paragraph 7, The above nitrogen compound is, A method for producing a lithium metal negative electrode, the method comprising: at least one selected from the group consisting of lithium nitrate, lithium bis fluorosulfonyl imide, lithium bis trifluoromethane sulfonimide, caprolactam, N-methyl-caprolactam, triethylamine, and tributylamine.

15. In paragraph 7, A method for manufacturing a lithium metal negative electrode, wherein the plating solution contains the nitrogen-based compound in an amount of 1 wt% to 100 wt% based on 100 wt% of the plating solution.

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