Lithium metal negative electrode structure, electrochemical device including the same, and method for manufacturing the lithium metal negative electrode structure

Abstract

The present invention relates to a lithium metal negative electrode structure, an electrochemical device including the same, and a method for manufacturing the lithium metal negative electrode structure. The lithium metal negative electrode structure includes a lithium metal negative electrode and a separator attached to at least one surface of the lithium metal negative electrode, the separator including a porous substrate and an inorganic layer including inorganic nanoparticles having a size of 5 to 200 nm coated on the porous substrate, the inorganic layer being positioned between the lithium metal negative electrode and the porous substrate. The lithium metal negative electrode structure can also be manufactured using a rolling or pressing process, which can make the surface of the lithium metal negative electrode uniform, improve sealing between the inorganic layer and the lithium metal negative electrode, suppress lithium dendritic growth, and minimize lithium reactions during life cycles.

Description

Technical Field

[0001] The present invention relates to a lithium metal negative electrode structure, an electrochemical element including the same, and a method for manufacturing the lithium metal negative electrode structure.

Background Art

[0002] Due to the trend of miniaturization, light weight, and portability of electric and electronic products, the secondary battery, which is a core component, is also required to be lightweight and miniaturized, and the development of a battery with high output and high energy density is demanded. In response to such demands, among the high-performance next-generation advanced new batteries that have recently received the most attention, one is the lithium metal secondary battery.

[0003] The lithium metal negative electrode is currently attracting attention as a core material for next-generation batteries. Compared with the negative electrode used in commonly used lithium-ion secondary batteries, it has a specific capacity of more than 10 times, and can epoch-makingly reduce the weight and thickness of the negative electrode. It is usually used for the development of batteries with an energy density of 400 Wh / kg or more than 1,000 Wh / L.

[0004] The method for manufacturing a lithium metal negative electrode generally includes extrusion and rolling to produce a lithium foil having a certain thickness, or pressing and adhering the produced lithium foil to a copper foil for use. Alternatively, CVD or thermal evaporation is used to deposit lithium on other substrates to produce a thin film.

[0005] Currently, the commonly used lithium negative electrode is a rolled foil-shaped lithium foil. However, during the processes of extrusion, rolling, and crimping, lithium is exposed to oils, impurities, etc. for processability, or due to excessive rolling to reduce the thickness of the lithium foil, the surface is subjected to non-uniform patterns and damage. This leads to non-uniform surface reactions of the lithium negative electrode, and during charging / discharging of the battery, it causes non-uniform growth of lithium dendrites, increasing the possibility of lifespan degradation and safety accidents due to internal short circuits.

[0006] To suppress lithium dendritic growth, inorganic substances, polymer coatings, or solid electrolytes are utilized. However, directly coating the lithium metal negative electrode involves many difficulties in process development due to the reactivity and physical properties of lithium metal itself. Except for methods such as vapor deposition, there is no coating method that can be actually applied. In the case of vapor deposition, there are difficulties in applying it to the size of the sample and continuous roll processes, and it is limited to small-scale research and development use. In the case of solid electrolytes, due to the interfacial resistance problem with the electrode and the limit of the sample size, there are actually difficulties in applying it to mass-produced batteries.

Summary of the Invention

Problems to be Solved by the Invention

[0007] One aspect of the present invention is to provide a lithium metal negative electrode structure that can form a lithium metal negative electrode with a uniform surface, suppress lithium dendritic growth, and minimize lithium reactions in the lifespan cycle.

[0008] Another aspect of the present invention is to provide an electrochemical element including the lithium metal negative electrode structure.

[0009] Still another aspect of the present invention is to provide a manufacturing method of the lithium metal negative electrode structure.

Means for Solving the Problems

[0010] In one aspect of the present invention, a lithium metal negative electrode, a separator attached to at least one surface of the lithium metal negative electrode, the separator including a porous substrate and an inorganic layer including inorganic nanoparticles having a size of 5 to 200 nm coated on the porous substrate, and the inorganic layer being located between the lithium metal negative electrode and the porous substrate, and a lithium metal negative electrode structure including the same are provided.

[0011] In another aspect of the present invention, an electrochemical element including the lithium metal negative electrode structure is provided.

[0012] In still another aspect of the present invention, a step of binding a separator to at least one surface of a lithium metal negative electrode using a rolling roll or a rolling press is included, the separator includes a porous substrate and an inorganic layer including inorganic nanoparticles having a size of 5 to 200 nm coated on the porous substrate, and a method for manufacturing the lithium metal negative electrode structure in which the inorganic layer is located between the lithium metal negative electrode and the porous substrate is provided.

Effect of the Invention

[0013] According to one embodiment, the lithium metal negative electrode structure has a uniform surface of the lithium metal negative electrode, improves the sealing between the inorganic layer and the lithium metal negative electrode, suppresses lithium dendritic growth, and can minimize the reaction of lithium in the life cycle. Through this, the lithium metal negative electrode structure can be applied to various electrochemical elements including lithium metal secondary batteries, and the life and stability can be improved.

Brief Description of the Drawings

[0014]

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Figure 4B

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Mode for Carrying Out the Invention

[0015] The present inventive concept described below can be subjected to various transformations and can have various embodiments. However, specific embodiments are illustrated in the drawings and will be described in detail by detailed description. However, they are not intended to limit the present inventive concept to specific embodiments, and it should be understood that they include all transformations, equivalents, or alternatives included in the technical scope of the present inventive concept.

[0016] The terms used below are merely those used in the description of specific embodiments and are not intended to limit the inventive concept. Singular expressions include plural expressions unless the context clearly dictates otherwise. Hereinafter, terms such as "comprising" or "having" indicate the presence of features, numbers, steps, operations, components, parts, elements, materials, or combinations thereof described in the specification, and it should not be understood as precluding the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, elements, materials, or combinations thereof. The " / " used below is interpreted as "and" or "or" depending on the context.

[0017] In the drawings, diameters, lengths, and thicknesses are shown enlarged or reduced in order to clearly represent various components, layers, and regions. Throughout the specification, similar parts are denoted by the same reference numerals. Throughout the specification, when a part such as a layer, film, region, or plate is said to be "on" or "above" another part, it includes not only the case where it is directly above the other part but also the case where there are additional parts in between. Throughout the specification, terms such as first and second can be used in the description of various components, and the components are not limited by the terms. The terms are used only for the purpose of distinguishing one component from another. In the drawings, a part of a component may be omitted, but it is for the purpose of assisting in the understanding of the features of the invention and is not intended to exclude the omitted component.

[0018] Hereinafter, with reference to the accompanying drawings, an exemplary lithium metal negative electrode structure, an electrochemical element including the same, and a method for manufacturing the lithium metal negative electrode structure will be described in more detail.

[0019] A lithium metal negative electrode structure according to an embodiment is a lithium metal negative electrode, A separator attached to at least one surface of the lithium metal negative electrode, the separator including a porous substrate and an inorganic layer including inorganic nanoparticles with a size of 5 to 200 nm coated on the porous substrate, the inorganic layer being located between the lithium metal negative electrode and the porous substrate, and including the separator.

[0020] The lithium metal negative electrode structure is in a rolled state in which the lithium metal negative electrode and the separator coated with the inorganic layer are integrally obtained through a rolling process. Thus, unlike the existing lithium metal negative electrode having a non-uniform surface, in the lithium metal negative electrode structure, the lithium metal negative electrode has a uniform surface with a surface roughness (Ra) of 1 or less. Currently, in the case of a lithium metal negative electrode through general roll rolling that has been commercialized, it is difficult to obtain a uniform surface due to the difference in elongation rate between the base material foil (copper) and the lithium foil.

[0021] The lithium metal negative electrode structure not only has a uniform surface for the lithium metal negative electrode, but also improves the sealing between the inorganic layer and the lithium metal negative electrode, suppresses the growth of lithium dendrites on the surface of the lithium metal negative electrode, minimizes the reaction of lithium in the life cycle, and can be applied to various electrochemical elements such as lithium metal secondary batteries, improving the life and stability.

[0022] Figure 1 is an exemplary schematic view of a lithium metal negative electrode structure according to an embodiment.

[0023] As can be seen from Figure 1, the lithium metal negative electrode structure 10 may have a structure in which a separator 12 including a porous substrate 12a coated with an inorganic layer 12b is bonded to at least one surface, for example, both surfaces of the lithium metal negative electrode 11.

[0024] The lithium metal negative electrode 11 is also a structure in which lithium thin films 11a are rolled on both surfaces of a current collector 11b such as a copper foil through roll rolling or the like.

[0025] According to one embodiment, the surface roughness (Ra) of the surface of the lithium metal negative electrode 11 is also 1 or less, for example, 0.9 or less, for example, 0.8 or less, for example, 0.7 or less, for example, 0.6 or less, for example, 0.5 or less, for example, 0.4 or less, for example, 0.3 or less, for example, 0.2 or less, or for example, 0.1 or less. By having the surface roughness within the above range, the lithium metal negative electrode will have a uniform surface, and during battery charging / discharging, non-uniform growth of lithium dendrites on the surface can be suppressed, and lifespan degradation and safety accidents due to internal short circuits can be suppressed.

[0026] The thickness of the lithium metal negative electrode is 100 μm or less, for example, 80 μm or less, or 50 μm or less, or 30 μm or less, or 20 μm or less. According to another embodiment, the thickness of the lithium metal negative electrode is also 0.1 to 60 μm. Specifically, the thickness of the lithium metal negative electrode is 1 to 25 μm, for example, 5 to 20 μm.

[0027] The separator includes a porous substrate and an inorganic layer including inorganic nanoparticles with a size of 5 to 200 nm coated on the porous substrate.

[0028] In the separation membrane, the porous substrate is also a porous membrane containing polyolefin. Polyolefin has an excellent short-circuit prevention effect and can improve battery stability due to the shutdown effect. For example, the porous substrate may be a membrane made of a resin such as one or more copolymers selected from polyethylene, polypropylene, polybutylene, polypentene, polyhexene, polyoctene, ethylene, propylene, butene, pentene, 4-methylpentene, hexene, and octene, a mixture thereof, or a combination thereof, but is not necessarily limited thereto. Any porous membrane that can be used in the technical field is possible. For example, a porous membrane made of a polyolefin-based resin, a porous membrane woven from polyolefin-based fibers, and an aggregate of a non-woven fabric containing polyolefin and insulating substance particles can be used. For example, a porous membrane containing polyolefin has excellent coatability for a binder solution for manufacturing a coating layer formed on the substrate, can reduce the membrane thickness of the separation membrane, increase the ratio of the active material in the battery, and increase the capacity per unit volume.

[0029] The thickness of the porous substrate is also 1 μm to 50 μm. For example, the thickness of the porous substrate is also 1 μm to 30 μm. For example, the thickness of the porous substrate is also 3 μm to 20 μm. For example, the thickness of the porous substrate is also 3 μm to 15 μm. For example, the thickness of the porous substrate is also 3 μm to 12 μm. If the thickness of the porous substrate is less than 1 μm, it is difficult to maintain the mechanical properties of the separation membrane. If the thickness of the porous substrate exceeds 50 μm, the internal resistance of the lithium battery increases, and the energy density of the lithium metal battery is also lost.

[0030] The inorganic layer contains inorganic nanoparticles with a size of 5 to 200 nm.

[0031] According to one embodiment, the inorganic nanoparticles may also include a ceramic material. The ceramic material may include, for example, alumina (Al2O3), silica (SiO2), zinc oxide, zirconium oxide (ZrO2), zeolite, titanium oxide (TiO2), barium titanate (BaTiO3), strontium titanate (SrTiO3), calcium titanate (CaTiO3), aluminum borate, iron oxide, calcium carbonate, barium carbonate, lead oxide, tin oxide, cerium oxide, calcium oxide, manganese tritoxide, magnesium oxide, niobium oxide, tantalum oxide, tungsten oxide, antimony oxide, aluminum phosphate, calcium silicate, zirconium silicate, ITO (indium tin oxide), titanium silicate, montmorillonite, saponite, vermiculite, hydrotalcite, kaolinite, kanemite, magadiite, and kenyaite, but is not limited thereto.

[0032] According to another embodiment, the inorganic nanoparticles may include a solid electrolyte material. The solid electrolyte material may also include at least one inorganic lithium ion conductor selected from the group consisting of oxide-based, phosphate-based, sulfide-based, and LiPON-based inorganic materials having lithium ion conductivity.

[0033] The inorganic lithium ion conductor may have, for example, one or more selected from the group consisting of garnet-type compounds, argyrodite-type compounds, LISICON (lithium super-ion-conductor) compounds, NASICON (Nasuper ionic conductor-like) compounds, lithium nitride, lithium hydride, perovskite, lithium halide, and sulfide-based compounds.

[0034] The inorganic lithium ion conductor may be, for example, garnet-based ceramics (Li 3+x La3M2O 12; 0 ≤ x ≤ 5, where M is at least one of W, Ta, Te, Nb, and Zr), doped garnet-based ceramics (Li 7-3x M’ x La3M2O 12 ; 0 < x ≤ 1, where M is at least one of W, Ta, Te, Nb, and Zr, and M’ is at least one of Al, Ga, Nb, Ta, Fe, Zn, Y, Sm, and Gd), Li 1+x+y Al x Ti 2-x Si y P 3-y O 12 (0 < x < 2, 0 ≤ y < 3), BaTiO3, Pb(Zr, Ti)O3 (PZT), Pb 1-x La x Zr 1-y Ti y O3 (PLZT) (0 ≤ x < 1, 0 ≤ y < 1), Pb(Mg 1 / 3 Nb 2 / 3 )O3 - PbTiO3 (PMN - PT), lithium phosphate (Li3PO4), lithium titanium phosphate (Li x Ti y (PO4)3; 0 < x < 2, 0 < y < 3), lithium aluminum titanium phosphate (Li x Al y Ti z (PO4)3; 0 < x < 2, 0 < y < 1, 0 < z < 3), Li 1+x+y (Al, Ga) x (Ti, Ge) 2-x Si y P 3-y O 12 (0 ≤ x ≤ 1, 0 ≤ y ≤ 1), lithium lanthanum titanate (Li x La y TiO3; 0 < x < 2, 0 < y < 3), lithium germanium thiophosphate (LixGeyPzSw; 0 < x < 4, 0 < y < 1, 0 < z < 1, 0 < w < 5), lithium nitride (Li x N y ; 0 < x < 4, 0 < y < 2), SiS2 (Li x Si y S z ; 0 ≤ < 3, 0 < y < 2, 0 < z < 4) - based glass, P2S5 (Li x Py S z ; glass in the system where 0≦x<3, 0<y<3, 0<z<7), Li 3x La 2 / 3-x TiO3 (0≦x≦1 / 6), Li7La3Zr2O 12 、Li 1+y Al y Ti 2-y (PO4)3 (0≦y≦1), Li 1+z Al z Ge 2-z (PO4)3 (0≦z≦1), Li2O, LiF, LiOH, Li2CO3, LiAlO2, ceramics in the Li2O - Al2O3 - SiO2 - P2O5 - TiO2 - GeO2 system, Li 10 GeP2S 12 、Li 3.25 Ge 0.25 P 0.75 S4, Li3PS4, Li6PS5Br, Li6PS5Cl, Li7PS5, Li6PS5I, Li 1.3 Al 0.3 Ti 1.7 (PO4)3, LiTi2(PO4)3, LiGe2(PO4)3, LiHf2(PO4)3, LiZr2(PO4)3, Li2NH2, Li3(NH2)2I, LiBH4, LiAlH4, LiNH2, Li 0.34 La 0.51 TiO 2.94 、LiSr2Ti2NbO9, Li 0.06 La 0.66 Ti 0.93 Al 0.03 O3, Li 0.34 Nd 0.55 TiO3, Li2CdCl4, Li2MgCl4, Li2ZnI4, Li2CdI4, Li 4.9 Ga 0.5+δ La3Zr 1.7 W 0.3 O 12 (0≦δ<1.6), Li 4.9 Ga 0.5+δ La3Zr 1.7 W 0.3 O 12 (1.7≦δ≦2.5), Li 5.39 Ga 0.5+δ La3Zr 1.7 W 0.3 O 12(0 ≦ δ ≦ 1.11), LPS (lithium phosphorus sulfide; Li3PS4), LTS (lithium tin sulfide; Li4SnS4), LPSCLL (lithium phosphorus sulfur chloride iodide; Li6PS5Cl 0.9 I 0.1 ), LSPS (lithium tin phosphorus sulfide; Li 10 SnP2S 12 ), may contain one or more selected from the group consisting of Li2S, Li2S - P2S5, Li2S - SiS2, Li2S - GeS2, Li2S - B2S5, and Li2S - Al2S5.

[0035] For example, as the inorganic lithium ion conductor, garnet - type LLZO (lithium lanthanum zirconium oxide; Li 7-3x Al x La3Zr2O 12 )(0 < x ≦ 1), Al - doped LLZO (lithium lanthanum zirconium oxide; Li 7-3x Al x La3Zr2O 12 )(0 < x ≦ 1) is used. As similar - oxide - type solid electrolytes, LLTO (lithium lanthanum titanate; (Li 0.34 La 0.51 TiO y )(0 < y ≦ 3), LATP (lithium aluminum titanium phosphate; Li 1.3 Al 0.3 Ti 1.7 (PO4)3), etc. are used. As sulfur compounds, LPS (lithium phosphorus sulfide; Li3PS4), LTS (lithium tin sulfide; Li4SnS4), LPSCLL (lithium phosphorus sulfur chloride iodide; Li6PS5Cl 0.9 I 0.1)、LSPS (lithium tin phosphorus sulfide; Li 10 SnP2S 12 ) etc. can be used.

[0036] The inorganic nanoparticles can have a particle or columnar structure, or other amorphous forms.

[0037] The size of the inorganic nanoparticles can also be 5 to 200 nm, for example, 10 to 150 nm, for example, 20 to 100 nm, for example, 10 to 100 nm. When the average particle size of the inorganic nanoparticles is within the aforementioned range, the uniformity of the surface of the lithium metal negative electrode can be improved through the rolling process. In this specification, "the size of the inorganic nanoparticles" refers to the average diameter when the inorganic nanoparticles are spherical, and the major axis length when the inorganic nanoparticles are non-spherical. The size of the inorganic nanoparticles can be measured using a particle size measuring instrument or an electron scanning microscope, etc.

[0038] The content of the inorganic nanoparticles is at least 10 wt% or more, 15 wt% or more, 20 wt% or more, 30 wt% or more, 40 wt% or more, 50 wt% or 90 wt% or more based on the total weight of the coating layer. For example, the content of the inorganic nanoparticles is also in the range of 70 to 98 wt% based on the total weight of the coating layer. Within the aforementioned range, the surface uniformity of the lithium metal negative electrode and the sealing between the inorganic layer and the surface of the lithium metal negative electrode can be improved.

[0039] The inorganic layer may further contain an organic binder. In that case, the inorganic layer can have a form in which inorganic nanoparticles are dispersed in a matrix composed of the organic binder.

[0040] The organic binder may include, for example, at least one selected from polyvinylidene fluoride, polyvinylidene fluoride - hexafluoropropylene, polyvinylidene chloride, polybenzimidazole, polyimide, polyvinyl acetate, polyacrylonitrile, polyurethane, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, polystyrene, polymethyl methacrylate, polyaniline, acrylonitrile - butadiene - styrene, phenolic resin, epoxy resin, polyethylene terephthalate, polytetrafluoroethylene, polyphenyl sulfide, polyamideimide, polyetherimide, polyethylene sulfone, polyamide, polyacetal, polyethylene oxide, polyethylene glycol diacrylate, polyethylene glycol monoacrylate, polyphenylene oxide, polybutylene terephthalate, ethylene - propylene - diene terpolymer (EPDM), sulfonated EPDM, styrene - butadiene rubber, fluororubber, and copolymers thereof.

[0041] When the inorganic layer contains inorganic nanoparticles and an organic binder, the content of the organic binder is also in the range of 50 to 99% by weight based on the total weight of the inorganic nanoparticles and the organic binder, for example, 60 to 98% by weight, 70 to 97% by weight, or 80 to 96% by weight. When the content of the organic binder is within the above - mentioned range, the binding between the inorganic layer and the lithium metal negative electrode can be further improved.

[0042] According to one embodiment, the thickness of the inorganic layer is also 0.1 to 50 μm, for example, 1 to 5 μm, for example, 2 to 4 μm. In the above - mentioned range, during the rolling process of the lithium metal negative electrode and the separator, while making the surface of the lithium metal negative electrode a uniform surface, the sealing between the inorganic layer and the lithium metal negative electrode can be improved.

[0043] According to one embodiment, the separation membrane may further include a polymer coating layer on the inorganic layer. The polymer coating layer can further improve the adhesion between the inorganic layer and the lithium metal negative electrode and further suppress the growth of lithium dendrites.

[0044] The material used for the polymer coating layer is, for example, polyvinylidene fluoride, polyvinylidene fluoride - hexafluoropropylene, polyvinylidene chloride, polybenzimidazole, polyimide, polyvinyl acetate, polyacrylonitrile, polyurethane, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, polystyrene, polymethyl methacrylate, polyaniline, acrylonitrile - butadiene - styrene, phenolic resin, epoxy resin, polyethylene terephthalate, polytetrafluoroethylene, polyphenyl sulfide, polyamide - imide, polyether - imide, polyethylene sulfone, polyamide, polyacetal, polyethylene oxide, polyethylene glycol diacrylate, polyethylene glycol monoacrylate, polyphenylene oxide, polybutylene terephthalate, ethylene - propylene - diene terpolymer (EPDM), sulfonated EPDM, styrene - butadiene rubber, fluororubber, and at least one selected from their copolymers.

[0045] According to one embodiment, the polymer coating layer may contain the same material as the organic binder used for the inorganic layer.

[0046] The thickness of the separation membrane is 14 to 20 μm, and the air permeability is 180 to 300 sec / 100cc, for example, also 185 sec / 100cc to 210 sec / 100cc. Within the above - mentioned range, the pores formed in the separation membrane are sufficiently opened, so that the ionic conductivity is excellent and the battery output and battery performance can be improved.

[0047] The lithium metal negative electrode structure improves the sealing between the inorganic layer and the surface of the lithium metal negative electrode, and the porosity between the lithium metal negative electrode and the inorganic layer is also 0 to 10%, for example, 0 to 9%, 0 to 8%, 0 to 7%, 0 to 6%, 0 to 5%, 0 to 4%, 0 to 3%, 0 to 2%, or 0 to 1%. When the porosity between the lithium metal negative electrode and the inorganic layer is within the above range, the growth of lithium dendrites can be maximally suppressed on the surface of the lithium metal negative electrode.

[0048] According to one embodiment, the lithium metal negative electrode structure can bond the separator coated with the inorganic layer to the surface of the lithium metal negative electrode through a rolling process, and through this, the surface uniformity, which is the biggest problem of the lithium metal negative electrode, can be improved, and the sealing between the inorganic layer and the surface of the lithium metal negative electrode can be improved, thereby contributing to a uniform reaction, maximizing the suppression of lithium dendrite growth, improving the life performance, and suppressing internal short circuits and the resulting cell ignition and explosion.

[0049] FIG. 2 illustrates a battery stack structure using the lithium metal negative electrode structure according to one embodiment.

[0050] As can be seen from FIG. 2, the lithium metal negative electrode structure 10 and the positive electrode 20 can be directly stacked to assemble a pouch single cell, which can be applied to various batteries. Here, the positive electrode 20 may have the positive electrode active material layer 21 disposed on both sides of the current collector 22 such as an aluminum foil.

[0051] Hereinafter, a method for manufacturing the lithium metal negative electrode structure according to one embodiment will be described.

[0052] The manufacturing method of the lithium metal negative electrode structure according to an embodiment includes a step of binding a separator to at least one surface of the lithium metal negative electrode by using a rolling roll or a rolling press. The separator includes a porous substrate and an inorganic layer including inorganic nanoparticles with an average particle diameter of 5 to 200 nm coated on the porous substrate. The inorganic layer is positioned between the lithium metal negative electrode and the porous substrate.

[0053] FIG. 3 exemplarily illustrates a manufacturing method of a lithium metal negative electrode structure using a rolling roll according to an embodiment.

[0054] As can be seen from FIG. 3, a separator including a porous substrate coated with an inorganic layer is bound to at least one surface, for example, both surfaces of the lithium metal negative electrode by using a rolling process.

[0055] The binding step is also carried out by hot rolling or cold rolling.

[0056] The hot rolling is carried out, for example, at 30 to 90°C, and the cold rolling is carried out, for example, at 20 to 30°C. The binding is carried out with a linear pressure in the range of 50 kgf to 1,000 kgf. In a section where the surface uniformity is improved, the linear pressure is also in the range of 200 kgf to 500 kgf. In the case of hot rolling, even a low pressure can bring about a further improved binding force.

[0057] The lithium metal negative electrode structure obtained through such a rolling process can be easily applied to an existing battery manufacturing process without significant changes, has mass productivity, and can also be used in future all-solid-state batteries.

[0058] The manufacturing method of the lithium metal negative electrode structure using the rolling process can bond a separator coated with an inorganic layer to the surface of the lithium metal negative electrode, improve the surface uniformity of the lithium metal negative electrode, and improve the sealing between the inorganic layer and the surface of the lithium metal negative electrode. Through this, a lithium metal negative electrode structure that can induce a uniform reaction, maximize the suppression of lithium dendritic growth, and improve battery life and stability can be provided.

[0059] An electrochemical element according to an embodiment includes the aforementioned lithium metal negative electrode structure. The electrochemical element including the lithium metal negative electrode structure can suppress lithium resin growth and improve life and stability.

[0060] The electrochemical element is also a lithium secondary battery such as a lithium-ion battery, a lithium polymer battery, a lithium metal battery, a lithium-air battery, or a lithium all-solid-state battery.

[0061] A lithium secondary battery according to an embodiment includes a negative electrode including the aforementioned lithium metal negative electrode structure, a positive electrode disposed opposite to the negative electrode, and an electrolyte disposed between the negative electrode and the positive electrode.

[0062] The negative electrode includes the aforementioned lithium metal negative electrode structure. The lithium metal negative electrode structure is also manufactured by the aforementioned manufacturing method.

[0063] In addition to the aforementioned lithium metal negative electrode structure, the negative electrode may further include a negative electrode active material material generally used as a negative electrode active material for a lithium battery in the art. Examples of the generally used negative electrode active material material may include one or more selected from the group consisting of lithium metal, a metal alloyable with lithium, transition metal oxides, non-transition metal oxides, and carbon-based materials.

[0064] For example, the metals that can form an alloy with lithium include Si, Sn, Al, Ge, Pb, Bi, Sb, Si-Y alloy (where Y is an alkali metal, alkaline earth metal, Group 13 element, Group 14 element, transition metal, rare earth element, or a combination thereof, and is not Si), Sn-Y alloy (where Y is an alkali metal, alkaline earth metal, Group 13 to 16 element, transition metal, rare earth element, or a combination thereof, and is not Sn), and the like. Examples of the element Y include Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Ti, Ge, P, As, Sb, Bi, S, Se, Te, Po, or a combination thereof.

[0065] For example, the transition metal oxides also include lithium titanate, vanadium oxide, lithium vanadate, and the like.

[0066] For example, the non-transition metal oxides include SnO2, SiO x (0 < x ≤ 2), and the like.

[0067] The carbon-based material may also be crystalline carbon, amorphous carbon, or a mixture thereof. The crystalline carbon may also be graphite such as amorphous, plate-like, flaky, spherical, or fiber-type natural graphite or artificial graphite. The amorphous carbon may also be soft carbon (low-temperature calcined carbon), hard carbon, mesophase pitch carbide, calcined coke, and the like.

[0068] When using both the aforementioned negative electrode active material and the carbon-based material, the oxidation reaction of the silicon-based active material can be suppressed, an SEI (solid electrolyte interface) film can be effectively formed, a stable film can be formed, the electrical conductivity can be improved, and the charge / discharge characteristics of lithium can be further improved.

[0069] Common negative electrode active material materials can be coated on the surface of the aforementioned lithium metal negative electrode structure or used in any other combined form. For example, after mixing a negative electrode active material, a binder, and optionally a conductive material in a solvent to produce a negative electrode active material composition, it is formed into a certain shape, applied to the lithium metal negative electrode structure, or applied to a current collector such as a copper foil, and then combined with the lithium metal negative electrode structure.

[0070] The binder used in the negative electrode active material composition is a component that helps bind the negative electrode active material and the conductive material and bind the negative electrode active material and the current collector, and is added in an amount of 1 to 50 parts by weight based on 100 parts by weight of the negative electrode active material. For example, based on 100 parts by weight of the negative electrode active material, the binder can be added in the range of 1 to 30 parts by weight, 1 to 20 parts by weight, or 1 to 15 parts by weight. Examples of such binders include polyvinylidene fluoride, polyvinyl chloride, polybenzimidazole, polyimide, polyvinyl acetate, polyacrylonitrile, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl pyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, polystyrene, polymethyl methacrylate, polyaniline, acrylonitrile butadiene styrene, phenol resin, epoxy resin, polyethylene terephthalate, polytetrafluoroethylene, polyphenyl sulfide, polyamideimide, polyetherimide, polyethylene sulfone, polyamide, polyacetal, polyphenylene oxide, polybutylene terephthalate, ethylene - propylene - diene terpolymer (EPDM), sulfonated EPDM, styrene butadiene rubber, fluororubber, various copolymers, etc.

[0071] The negative electrode may further selectively contain a conductive material in order to provide a conductive path to the negative electrode active material and further improve electrical conductivity. As the conductive material, generally, any material can be used as long as it is used in a lithium battery. Examples thereof include carbon-based materials such as carbon black, acetylene black, ketjen black, and carbon fiber (e.g., vapor-grown carbon fiber); metal-based materials such as metal powders or metal fibers of copper, nickel, aluminum, silver, etc.; conductive polymers such as polyphenylene derivatives, or a conductive material containing a mixture thereof can be used. The content of the conductive material can be appropriately adjusted and used. For example, the weight ratio of the negative electrode active material to the conductive material is also added in the range of 99:1 to 90:10.

[0072] As the solvent, N-methylpyrrolidone (NMP), acetone, water, etc. can be used. The content of the solvent is 1 to 10 parts by weight based on 100 parts by weight of the negative electrode active material. When the content of the solvent is within the above range, the operation for forming the active material layer is easy.

[0073] Also, the current collector is generally made to have a thickness of 3 to 500 μm. The current collector is not particularly limited as long as it has conductivity without inducing a chemical change in the battery. For example, copper, stainless steel, aluminum, nickel, titanium, fired carbon, those surface-treated with carbon, nickel, titanium, silver, etc. on the surface of copper or stainless steel, aluminum-cadmium alloy, etc. can be used. Further, fine irregularities can be formed on the surface to strengthen the binding force of the negative electrode active material, and it is also used in various forms such as films, sheets, foils, nets, porous bodies, foams, and non-woven bodies.

[0074] The manufactured negative electrode active material composition can be directly coated on the lithium metal negative electrode structure, directly coated on the current collector, or cast on a separate support and then laminated the negative electrode active material film peeled from the support onto the copper foil current collector to obtain the negative electrode plate. The negative electrode is not limited to the forms listed above and can also be in other forms.

[0075] The negative electrode active material composition is not only used for manufacturing the electrodes of lithium secondary batteries, but also printed on a flexible electrode substrate and used for manufacturing printable batteries.

[0076] Separately, to prepare the positive electrode, a positive electrode active material composition in which a positive electrode active material, a conductive material, a binder, and a solvent are mixed is prepared.

[0077] As the positive electrode active material, any of the generally used thium-containing metal oxides in the technical field can be used as long as they are suitable.

[0078] For example, Li a A 1-b B b D2 (in the chemical formula, 0.90 ≦ a ≦ 1.8 and 0 ≦ b ≦ 0.5); Li a E 1-b B b O 2-c D c (in the chemical formula, 0.90 ≦ a ≦ 1.8, 0 ≦ b ≦ 0.5, 0 ≦ c ≦ 0.05); LiE 2-b B b O 4-c D c (in the chemical formula, 0 ≦ b ≦ 0.5, 0 ≦ c ≦ 0.05); Li a Ni 1-b-c Co b B c D α (in the chemical formula, 0.90 ≦ a ≦ 1.8, 0 ≦ b ≦ 0.5, 0 ≦ c ≦ 0.05, 0 < α ≦ 2); Li a Ni 1-b-c Co b Bc O 2-α F α (In the above chemical formula, 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2); Li a Ni 1-b-c Co b B c O 2-α F α (In the above chemical formula, 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2); Li a Ni 1-b-c Mn b B c D α (In the above chemical formula, 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α ≤ 2); Li a Ni 1-b-c Mn b B c O 2-α F α (In the above chemical formula, 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2); Li a Ni 1-b-c Mn b B c O 2-α F α (In the above chemical formula, 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05, 0 < α < 2); Li a Ni b E c G d O2(In the above chemical formula, 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0.001 ≤ d ≤ 0.1); Li a Ni b Co c Mn d GeO2(In the above chemical formula, 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0 ≤ d ≤ 0.5, 0.001 ≤ e ≤ 0.1); Li a NiG b O2(In the above chemical formula, 0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1); Li a CoG b O2(In the above chemical formula, 0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1); Li a MnGb O2 (in the above chemical formula, 0.90 ≦ a ≦ 1.8, 0.001 ≦ b ≦ 0.1); Li a Mn2G b O4 (in the above chemical formula, 0.90 ≦ a ≦ 1.8, 0.001 ≦ b ≦ 0.1); QO2; QS2; LiQS2; V2O5; LiV2O5; LiIO2; LiNiVO4; Li (3-f) J2(PO4)3 (0 ≦ f ≦ 2); Li (3-f) Fe2(PO4)3 (0 ≦ f ≦ 2); A compound represented by any one of the chemical formulas of LiFePO4 can be used:

[0079] In the above chemical formula, A is Ni, Co, Mn, or a combination thereof; B is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof; D is O, F, S, P, or a combination thereof; E is Co, Mn, or a combination thereof; F is F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; Q is Ti, Mo, Mn, or a combination thereof; I is Cr, V, Fe, Sc, Y, or a combination thereof; J is V, Cr, Mn, Co, Ni, Cu, or a combination thereof.

[0080] The positive electrode active material is, for example, lithium cobalt oxide of LiCoO2; lithium nickel oxide of chemical formula LiNiO2; chemical formula Li 1+x Mn 2-x O4 (where x is 0 to 0.33), lithium manganese oxides such as LiMnO3, LiMn2O3 or LiMnO2; lithium copper oxide of chemical formula Li2CuO2; lithium iron oxide of chemical formula LiFe3O4; lithium vanadium oxide of chemical formula LiV3O8; copper vanadium oxide of chemical formula Cu2V2O7; vanadium oxide of chemical formula V2O5; chemical formula LiNi 1-x MxO2 (where M is Co, Mn, Al, Cu, Fe, Mg, B or Ga, and x = 0.01 to 0.3) of lithium nickel oxide; chemical formula LiMn 2-x Mx Lithium manganese composite oxides represented by O2 (where M is Co, Ni, Fe, Cr, Zn or Ta and x = 0.01 to 0.1) or Li2Mn3MO8 (where M is Fe, Co, Ni, Cu or Zn); Lithium manganese oxides in which part of Li in the chemical formula LiMn2O4 is substituted with alkaline earth metal ions; Disulfide compounds; Iron molybdate oxides of the chemical formula Fe2(MoO4)3, and one or more of them can be selected and used.

[0081] Here, it goes without saying that those having a coating layer on the surface of the compound can also be used, or the compound and a compound having a coating layer can be mixed and used. The coating layer may contain a coating element compound such as an oxide of the coating element, a hydroxide of the coating element, an oxyhydroxide of the coating element, an oxycarbonate of the coating element, or a hydroxycarbonate of the coating element. The compounds forming those coating layers may be amorphous or crystalline. As the coating elements contained in the coating layer, Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, or a mixture thereof can be used. As long as the formation process of the coating layer can coat the aforementioned compound with such an element by a method (such as a spray coating method, an immersion method, etc.) that does not adversely affect the physical properties of the positive electrode active material, any coating method can be used, and since this is a content that can be sufficiently understood by those skilled in the art in this field, detailed description is omitted.

[0082] For example, LiNiO2, LiCoO2, LiMn x O 2x (x = 1, 2), LiNi 1-x Mn x O2 (0 < x < 1), LiNi 1-x-y Co x Mn y O2 (0 ≤ x ≤ 0.5, 0 ≤ y ≤ 0.5), LiFeO2, V2O5, TiS, MoS, etc. can be used.

[0083] In the positive electrode active material composition, the conductive material, binder, and solvent can be the same as those in the above-described negative electrode active material composition. In some cases, a plasticizer can be further added to the positive electrode active material composition and the negative electrode active material composition to form pores inside the electrode plate. The contents of the above-described positive electrode active material, conductive material, binder, and solvent are at levels generally used in lithium batteries.

[0084] The positive electrode current collector is not particularly limited as long as it has a thickness of 3 to 500 μm and has high conductivity without inducing a chemical change in the battery. For example, stainless steel, aluminum, nickel, titanium, fired carbon, or a surface-treated material with carbon, nickel, titanium, silver, etc. on the surface of aluminum or stainless steel can be used. The current collector can also form fine irregularities on its surface to enhance the adhesion of the positive electrode active material and can have various forms such as a film, sheet, foil, net, porous body, foam, or non-woven fabric.

[0085] The prepared positive electrode active material composition can be directly coated and dried on the positive electrode current collector to produce a positive electrode plate. As an alternative, the positive electrode active material composition can be cast on a separate support, and then the film obtained by peeling it from the support can be laminated on the positive electrode current collector to produce a positive electrode plate.

[0086] The positive electrode and the negative electrode are also separated by a separator membrane. As the separator membrane, any one can be used as long as it is generally used in a lithium battery. In particular, those having a low resistance to ion movement of the electrolyte and excellent electrolyte moisture retention ability are suitable. For example, it is a material selected from among glass fiber, polyester, Teflon (registered trademark), polyethylene, polypropylene, polytetrafluoroethylene (PTFE), and combinations thereof, and may be in the form of a non-woven fabric or a woven fabric. The separator membrane has a pore diameter of 0.01 to 10 μm and a thickness of generally 5 to 300 μm is used.

[0087] The lithium salt-containing non-aqueous electrolyte consists of a non-aqueous electrolyte and lithium. As the non-aqueous electrolyte, non-aqueous electrolytic solution, solid electrolyte, inorganic solid electrolyte, etc. are used.

[0088] As the non-aqueous electrolytic solution, for example, aprotic organic solvents such as N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, gamma-butyrolactone, 1,2-dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, formamide, dimethylformamide, acetonitrile, nitromethane, methyl formate, methyl acetate, triester phosphate, trimethoxymethane, dioxolane derivative, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate derivative, tetrahydrofuran derivative, ether, methyl pyruvate, ethyl propionate can be used.

[0089] As the organic solid electrolyte, for example, polyethylene derivatives, polyethylene oxide derivatives, polypropylene oxide derivatives, phosphate ester polymers, polyaditation lysine, polyester sulfide, polyvinyl alcohol, polyvinylidene fluoride, polymers containing ionic dissociation groups, etc. can be used.

[0090] As the inorganic solid electrolyte, for example, nitrides, halides, sulfates, etc. of Li such as Li3N, LiI, Li5NI2, Li3N-LiI-LiOH, LiSiO4, LiSiO4-LiI-LiOH, Li2SiS3, Li4SiO4, Li4SiO4-LiI-LiOH, Li3PO4-Li2S-SiS2 can be used.

[0091] Any of the lithium salts can be used as long as they are commonly used in lithium batteries and are substances that are easily dissolved in the non-aqueous electrolyte. For example, substances such as LiCl, LiBr, LiI, LiClO4, LiBF4, LiB 10 Cl 10 , LiPF6, LiCF3SO3, LiCF3CO2, LiAsF6, LiSbF6, LiAlCl4, CH3SO3Li, CF3SO3Li, (CF3SO2)2NLi, F2LiNO4S2, lithium chloroborate, lithium lower aliphatic carboxylate, lithium 4-phenylborate, imide, etc. can be used alone or in combination of one or more.

[0092] Lithium secondary batteries can be classified into lithium-ion batteries, lithium-ion polymer batteries, and lithium polymer batteries according to the types of the separation membrane and electrolyte used, and can also be classified into cylindrical, rectangular, coin-type, pouch-type, etc. according to the form, and can be divided into bulk type and thin film type according to the size.

[0093] Since the manufacturing methods of these batteries are well-known in the art, detailed descriptions are omitted.

[0094] The electrochemical element is also a lithium metal battery.

[0095] The lithium metal battery can also be manufactured in a stack type in which a positive electrode and a lithium metal negative electrode structure are laminated. As an alternative, instead of the laminated form, the positive electrode and the lithium metal negative electrode structure can be manufactured in a jelly roll type in a roll form through a winding method.

[0096] FIG. 9 schematically shows the structure of a lithium metal battery according to an embodiment.

[0097] As can be seen from FIG. 9, the lithium metal battery 11 includes a positive electrode 13, a negative electrode 12 including a lithium metal negative electrode structure, and a separator 14. The positive electrode 13, the negative electrode 12, and the separator 14 are wound or folded and housed in a battery case 15. Next, an electrolyte is injected into the battery case 55, sealed with a cap assembly 16, and the lithium metal battery 11 is completed. The battery case can also be cylindrical, rectangular, thin-film type, etc. For example, the lithium metal battery can also be a large-sized thin-film battery. The lithium metal battery can also be a lithium-ion battery.

[0098] The lithium metal battery not only has excellent capacity and lifespan characteristics and is used as a power source for battery cells used in small devices, but can also be used as a unit cell in a medium- to large-sized battery pack or battery module including a number of battery cells used as a power source for medium- to large-sized devices. Examples of the medium- to large-sized devices include electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), etc.

[0099] Exemplary embodiments will be described in more detail through the following examples and comparative examples. However, these examples are for illustrating the technical idea, and the scope of the present invention is not limited only by them.

[0100] Example 1: Manufacture of Lithium Metal Anode Structure First, using alumina nanoparticles with an average particle size of 30 nm and an ACN (acetonitrile) solution containing 6 wt% polyacrylonitrile (PAN) as a polymer binder, a composition obtained by mixing so that the weight ratio of alumina nanoparticles:PAN is 94:6 was coated on a polyethylene substrate, and it was vacuum dried at 70 °C for 12 hours to prepare a separation membrane with an inorganic layer formed on one side of the polyethylene substrate.

[0101] On both sides of a roll - rolled lithium thin film (thickness 20 μm) from Honjo, Japan, the inorganic layer of the separation membrane was arranged so as to be in contact with the lithium thin film, and through a rolling process as shown in Figure 3, the separation membrane was bonded to the surface of the lithium thin film to manufacture a lithium metal negative electrode structure. At this time, hot rolling was advanced, the temperature was 55 °C, and the linear pressure was 250 kgf.

[0102] Comparative Example 1: Existing Lithium Metal Anode The roll - rolled lithium thin film (thickness 20 μm) from Honjo, Japan was used as Comparative Example 1.

[0103] Evaluation Example 1: Surface Observation and Surface Roughness Measurement of Lithium Metal Anode Figure 4A is a photograph of the lithium metal negative electrode of Comparative Example 1, Figure 4B is a photograph of the lithium metal negative electrode structure of Example 1, and Figure 4C is a photograph showing a lithium metal negative electrode with improved surface uniformity in the lithium metal negative electrode structure of Example 1.

[0104] As can be seen from Figures 4A to 4C, it was possible to visually confirm with the naked eye that the surface of the lithium metal negative electrode (Figure 4C) to which the separation membrane coated with the inorganic layer was bonded was smoother than the surface of the existing lithium metal negative electrode (Figure 4A).

[0105] More specifically, in order to confirm the surface roughness of those lithium metal negative electrode surfaces, for the lithium metal negative electrode of Comparative Example 1 and the lithium metal negative electrode structure of Example 1, a Keyence microscope was used for the lithium metal negative electrode to observe the surface and measure the surface roughness (Ra), and the results are shown in Figures 5 and 6 respectively.

[0106] As can be seen from FIGS. 5 and 6, in the case of the existing lithium metal negative electrode of Comparative Example 1, the surface roughness (Ra) value was shown to be 1.6, but for the lithium metal negative electrode structure of Example 1, after the inorganic layer was bound through the rolling process, it was clearly lower at 0.4. It was also possible to confirm a uniform surface in the mapping results and the optical microscope.

[0107] Example 2: Manufacture of Lithium Metal Battery Using the lithium metal negative electrode structure according to Example 1 as the negative electrode, the positive electrode was laminated in order, then placed in an aluminum pouch and vacuum packaged to manufacture a lithium metal battery.

[0108] Here, the positive electrode was manufactured as follows and used after being sufficiently impregnated in a 1,2-dimethoxyethane (DME) electrolyte in which 3.5 M LiFSI (lithium bis(fluorosulfonyl)imide) was dissolved in advance. For the manufacture of the positive electrode, first, LiNiMnCoO2, a conductive material (Super-P; Timcal Ltd.), polyvinylidene fluoride (PVdF), and N-pyrrolidone were mixed to obtain a positive electrode composition. In the positive electrode composition, the mixing weight ratio of LiNiMnCoO2, the conductive material, and PVDF was 96:2:2. The positive electrode composition was coated on an aluminum foil (thickness: about 12 μm), and the coated electrode plate was dried at 110° C. under vacuum to manufacture a positive electrode.

[0109] Comparative Example 2: Manufacture of Lithium Metal Battery As a negative electrode, except for using the lithium metal negative electrode according to Comparative Example 1, the same process as in Example 2 was carried out to manufacture a lithium metal battery.

[0110] Evaluation Example 2: Charge-Discharge Characteristics and Life Evaluation For the lithium metal batteries according to Example 2 and Comparative Example 2, after two formation cycles with a current of 0.05 C rate, CC-CV charge and discharge were carried out up to 200 times with a current of 0.5 C rate.

[0111] The results of measuring the discharge capacity for each cycle of the lithium metal batteries according to Example 2 and Comparative Example 2 are shown in FIG. 7. Further, the results of measuring the discharge capacity / charge capacity efficiency, that is, the Coulomb efficiency, for each cycle of the lithium metal batteries according to Example 2 and Comparative Example 2 are shown in FIG. 8. Here, the discharge capacity / charge capacity efficiency is calculated from the following formula (1).

[0112] [Formula (1)] Coulomb efficiency [%] = [discharge capacity in each cycle / charge capacity in each cycle] × 100 As can be seen from FIGS. 7 and 8, it can be seen that the lithium metal battery of Example 2 has improved discharge capacity and life characteristics compared to the lithium metal battery of Comparative Example 2. Further, it was confirmed that the internal short-circuit phenomenon was also significantly suppressed at the end of the life.

[0113] In the above, desirable embodiments according to the present invention have been described with reference to the drawings and examples, but they are merely exemplary, and those skilled in the art will be able to understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the protection scope of the present invention is defined by the scope of the claims.

Claims

1. A lithium metal negative electrode, and a separator attached to at least one surface of the lithium metal negative electrode, the separator including a porous substrate and an inorganic layer including inorganic nanoparticles having an average particle diameter of 5 to 200 nm coated on the porous substrate, the inorganic layer being located between the lithium metal negative electrode and the porous substrate, and the separator, wherein a surface roughness (Ra) of the surface of the lithium metal negative electrode is 1 μm or less, in a rolled state, A lithium metal negative electrode structure having a structure of porous substrate (12a) / inorganic layer (12b) / lithium thin film (11a) / copper foil (11b) / lithium thin film (11a) / inorganic layer (12b) / porous substrate (12a).

2. The lithium metal negative electrode structure according to claim 1, wherein an average particle diameter of the inorganic nanoparticles is 5 to 200 nm.

3. The lithium metal negative electrode structure according to claim 1, wherein the inorganic nanoparticles include a ceramic material.

4. The ceramic material is alumina (Al ２ O ３ ), silica (SiO ２ ), zinc oxide, zirconium oxide (ZrO ２ ), zeolite, titanium oxide (TiO ２ ), barium titanate (BaTiO ３ ), strontium titanate (SrTiO ３ ), calcium titanate (CaTiO ３ ), aluminum borate, iron oxide, calcium carbonate, barium carbonate, lead oxide, tin oxide, cerium oxide, calcium oxide, manganese tetroxide, magnesium oxide, niobium oxide, tantalum oxide, tungsten oxide, antimony oxide, aluminum phosphate, calcium silicate, zirconium silicate, ITO (indium tin oxide), titanium silicate, montmorillonite, saponite, vermiculite, hydrotalcite, kaolinite, kanemite, magadiite, and kenyaite, and includes at least one selected therefrom, the lithium metal negative electrode structure according to claim 3.

5. The lithium metal negative electrode structure according to claim 1, wherein the inorganic nanoparticles include a solid electrolyte material.

6. The lithium metal negative electrode structure according to claim 5, wherein the solid electrolyte material includes one or more inorganic lithium ion conductors selected from the group consisting of garnet-type compounds, argyrodite-type compounds, LISICON (lithium super-ion-conductor) compounds, NASICON (Na super ionic conductor-like) compounds, lithium nitride, lithium hydride, perovskite, lithium halide, and sulfide-based compounds.

7. The inorganic lithium ion conductor is garnet-based ceramics (Li ３＋ｘ La ３ M ２ O １２ (0 ≤ x ≤ 5, M is at least one of W, Ta, Te, Nb, and Zr), doped garnet-based ceramics (Li ７－３ｘ M' ｘ La ３ M ２ O １２ (0 < x ≤ 1, M is at least one of W, Ta, Te, Nb, and Zr, and M' is at least one of Al, Ga, Nb, Ta, Fe, Zn, Y, Sm, and Gd), Li １＋ｘ＋ｙ Al ｘ Ti ２－ｘ Si ｙ P ３－ｙ O １２ (0 < x < 2, 0 ≤ y < 3), BaTiO ３ , Pb(Zr,Ti)O ３ (PZT), Pb １－ｘ La ｘ Zr １－ｙ Ti ｙ O ３ (PLZT) (0 ≤ x < 1, 0 ≤ y < 1), Pb(Mg １／３ Nb ２／３ )O ３ - PbTiO ３ (PMN - PT), lithium phosphate (Li ３ PO ４ ), lithium titanium phosphate (Li ｘ Ti ｙ (PO ４ ) ３ , 0 < x < 2, 0 < y < 3), lithium aluminum titanium phosphate (Li ｘ Al ｙ Ti ｚ (PO ４ ) ３ , 0 < x < 2, 0 < y < 1, 0 < z < 3), Li １＋ｘ＋ｙ (Al, Ga) ｘ (Ti, Ge) ２－ｘ Si ｙ P ３－ｙ O １２ (0 ≤ x ≤ 1, 0 ≤ y ≤ 1), lithium lanthanum titanate (Li ｘ La ｙ TiO ３ , 0 < x < 2, 0 < y < 3), lithium germanium thiophosphate (LixGeyPzSw, 0 < x < 4, 0 < y < 1, 0 < z < 1, 0 < w < 5), lithium nitride (Li ｘ N ｙ , 0 < x < 4, 0 < y < 2), SiS ２ (Li ｘ Si ｙ S ｚ , 0 ≤ < 3, 0 < y < 2, 0 < z < 4) - based glass, P ２ S ５ (Li ｘ P ｙ S ｚ , 0 ≤ x < 3, 0 < y < 3, 0 < z < 7) - based glass, Li ３ｘ La ２／３－ｘ TiO ３ (0 ≤ x ≤ 1 / 6), Li ７ La ３ Zr ２ O １２ , Li １＋ｙ Al ｙ Ti ２－ｙ (PO ４ ) ３ (0 ≤ y ≤ 1) and Li １＋ｚ Al ｚ Ge ２－ｚ (PO ４ ) ３ (0 ≤ z ≤ 1), Li ２ O, LiF, LiOH, Li ２ CO ３ , LiAlO ２ , Li ２ O - Al ２ O ３ - SiO ２ - P ２ O ５ - TiO ２ - GeO ２ - based ceramics, Li １０ GePS ２ S １２ , Li ３．２５ Ge ０．２５ P ０．７５ S ４ , Li ３ PS ４ , Li ６ PS ５ Br, Li ６ PS ５ Cl, Li ７ PS ５ , Li ６ PS ５ I, Li １．３ Al ０．３ Ti １．７ (PO ４ ) ３ , LiTi ２ (PO ４ ) ３ , LiGe ２ (PO ４ ) ３ , LiHf ２ (PO ４ ) ３ , LiZr ２ (PO ４ ) ３ , Li ２ NH ２ , Li ３ (NH ２ ) ２ I, LiBH ４ , LiAlH ４ , LiNH ２ , Li ０．３４ La ０．５１ TiO ２．９４ , LiSr ２ Ti ２ NbO ９ , Li ０．０６ La ０．６６ Ti ０．９３ Al ０．０３ O ３ , Li ０．３４ Nd ０．５５ TiO ３ , Li ２ CdCl ４ , Li ２ MgCl ４ , Li ２ ZnI ４ , Li ２ CdI ４ , Li ４．９ Ga ０．５＋δ La ３ Zr １．７ W ０．３ O １２ (0 ≤ δ < 1.6), Li ４．９ Ga ０．５＋δ La ３ Zr １．７ W ０．３ O １２ (1.7 ≤ δ ≤ 2.5), Li ５．３９ Ga ０．５＋δ La ３ Zr １．７ W ０．３ O １２ (0 ≤ δ ≤ 1.11), LPS (lithium phosphorus sulfide; Li ３ PS ４ ), LTS (lithium tin sulfide; Li ４ SnS ４ ), LPSClL (lithium phosphorus sulfur chloride iodide; Li ６ PS ５ Cl ０．９ I ０．１ ), LSPS (lithium tin phosphorus sulfide; Li １０ SnP ２ S １２ ), Li ２ S, Li ２ S - P ２ S ５ , Li ２ S - SiS ２ , Li ２ S - GeS ２ , Li ２ S - B ２ S ５ , and Li ２ S - Al ２ S ５ The lithium metal negative electrode structure according to claim 6, which is selected from the group consisting of

8. The lithium metal negative electrode structure according to claim 1, wherein the inorganic layer further includes an organic binder.

9. The lithium metal negative electrode structure according to claim 8, wherein the inorganic layer has a form in which the inorganic nanoparticles are dispersed in a matrix made of the organic binder.

10. The lithium metal negative electrode structure according to claim 8, wherein the organic binder includes at least one selected from polyvinylidene fluoride, polyvinylidene fluoride - hexafluoropropylene, polyvinylidene chloride, polybenzimidazole, polyimide, polyvinyl acetate, polyacrylonitrile, polyurethane, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, polystyrene, polymethyl methacrylate, polyaniline, acrylonitrile - butadiene - styrene, phenol resin, epoxy resin, polyethylene terephthalate, polytetrafluoroethylene, polyphenyl sulfide, polyamideimide, polyetherimide, polyethylene sulfone, polyamide, polyacetal, polyethylene oxide, polyethylene glycol diacrylate, polyethylene glycol monoacrylate, polyphenylene oxide, polybutylene terephthalate, ethylene - propylene - diene terpolymer (EPDM), sulfonated EPDM, styrene - butadiene rubber, fluorine rubber, and copolymers thereof.

11. The lithium metal negative electrode structure according to claim 8, wherein the content of the inorganic nanoparticles is 50 to 99% by weight based on the total weight of the inorganic nanoparticles and the organic binder.

12. The lithium metal negative electrode structure according to claim 1, wherein the thickness of the inorganic layer is 0.1 to 10 μm.

13. The lithium metal negative electrode structure according to claim 1, wherein the separator further includes a polymer coating layer on the inorganic layer.

14. The polymer coating layer is made of polyvinylidene fluoride, polyvinylidene fluoride - hexafluoropropylene, polyvinylidene chloride, polybenzimidazole, polyimide, polyvinyl acetate, polyacrylonitrile, polyurethane, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl pyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, polystyrene, polymethyl methacrylate, polyaniline, acrylonitrile - butadiene - styrene, phenolic resin, epoxy resin, polyethylene terephthalate, polytetrafluoroethylene, polyphenyl sulfide, polyamideimide, polyetherimide, polyethylene sulfone, polyamide, polyacetal, polyethylene oxide, polyethylene glycol diacrylate, polyethylene glycol monoacrylate, polyphenylene oxide, polybutylene terephthalate, ethylene - propylene - diene terpolymer (EPDM), sulfonated EPDM, styrene - butadiene rubber, fluorine rubber, and at least one selected from their copolymers, the lithium metal negative electrode structure according to claim 13.

15. The lithium metal negative electrode structure according to claim 1, wherein the porous substrate is a polyolefin substrate.

16. The lithium metal negative electrode structure according to claim 15, wherein the polyolefin substrate contains one or more copolymers selected from polyethylene, polypropylene, polybutylene, polypentene, polyhexene, polyoctene, ethylene, propylene, butene, pentene, 4 - methylpentene, hexene and octene, a mixture thereof or a combination thereof.

17. The lithium metal negative electrode structure according to claim 1, wherein the thickness of the porous substrate is 1 μm to 50 μm.

18. An electrochemical element comprising the lithium metal negative electrode structure according to any one of claims 1 to 17.

19. The electrochemical element according to claim 18, wherein the electrochemical element includes one or more selected from batteries, storage batteries, supercapacitors, fuel cells, sensors and electrochromic devices.

20. A positive electrode, A lithium metal battery comprising a negative electrode including the lithium metal negative electrode structure according to any one of claims 1 to 17.

21. including a step of binding a separator to at least one surface of a lithium metal negative electrode using a rolling roll or a rolling press; The separator includes a porous substrate and an inorganic layer including inorganic nanoparticles having an average particle diameter of 5 to 200 nm coated on the porous substrate, and the inorganic layer is positioned between the lithium metal negative electrode and the porous substrate. The method for manufacturing a lithium metal negative electrode structure according to any one of claims 1 to 16.

22. The method for manufacturing a lithium metal negative electrode structure according to claim 21, wherein the binding step is performed by hot rolling or cold rolling.

23. The hot rolling is performed at 40 to 80°C, the cold rolling is performed at 20 to 30°C, and the binding is performed at a linear pressure in the range of 50 kgf to 1,000 kgf. The method for manufacturing a lithium metal negative electrode structure according to claim 22.

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