Lithium metal battery, method of preparing the same, and lithium metal battery module as a unit cell including the lithium metal battery

Abstract

A lithium metal battery, a method for manufacturing the same, and a lithium metal battery module comprising the lithium metal battery as a unit cell are disclosed. The lithium metal battery comprises a negative electrode layer comprising lithium metal or a lithium alloy; a solid electrolyte layer disposed on the negative electrode layer; and a positive electrode layer disposed on the solid electrolyte layer. It further comprises a region comprising an intermediate layer and a region not comprising an intermediate layer between the negative electrode layer and the solid electrolyte layer. The region comprising the intermediate layer comprises an intermediate layer comprising a carbon material, and at least a portion of the region not comprising the intermediate layer may comprise one or more electrolytes selected from a liquid electrolyte, a gel electrolyte, and a polymer electrolyte.

Description

Technology Field

[0001] The present disclosure relates to a lithium metal battery, a method for manufacturing the same, and a lithium metal battery module comprising the lithium metal battery as a unit cell. Background Technology

[0002] Lithium metal batteries employing solid electrolytes instead of flammable organic solvent electrolytes are attracting significant attention for the development of batteries with high energy density and safety. Lithium metal batteries utilize lithium metal or lithium alloys as the negative electrode layer, or employ methods that do not form a negative electrode active material layer on the negative electrode current collector.

[0003] Generally, lithium metal batteries are manufactured using cold isostatic pressing (CIP) and / or warm isostatic pressing (WIP). However, lithium metal batteries manufactured by these methods have gap regions or voids between the negative electrode layer and the solid electrolyte layer after assembly due to high pressure and low or high temperatures. As a result, the interfacial resistance between the negative electrode layer and the solid electrolyte layer increases, and charge / discharge characteristics deteriorate.

[0004] Therefore, there is a demand for a lithium metal battery capable of improving charge / discharge characteristics by lowering the interfacial resistance between the negative electrode layer and the solid electrolyte layer while improving contact, a method for manufacturing the same, and a lithium metal battery module comprising the lithium metal battery as a unit cell. The problem to be solved

[0005] One aspect is to provide a lithium metal battery with low charge transfer resistance between the solid electrolyte layer and the cathode layer, and improved limiting current density and capacity per area.

[0006] Another aspect is to provide a method for manufacturing the above-mentioned lithium metal battery.

[0007] Another aspect is to provide a lithium metal battery module comprising the above-mentioned lithium metal battery as a unit cell. means of solving the problem

[0008] Depending on one aspect,

[0009] A negative electrode layer comprising lithium metal or lithium alloy;

[0010] A solid electrolyte layer disposed on the above cathode layer; and

[0011] A positive electrode layer disposed on the solid electrolyte layer; comprising

[0012] The region including an intermediate layer and a region not including an intermediate layer are further included between the above cathode layer and the above solid electrolyte layer.

[0013] The region including the above intermediate layer includes an intermediate layer including a carbon material, and

[0014] A lithium metal battery is provided in which at least a portion of the region not including the above intermediate layer comprises one or more electrolytes selected from a liquid electrolyte, a gel electrolyte, and a polymer electrolyte.

[0015] Depending on other aspects of work,

[0016] A step of preparing a composition for forming an intermediate layer by mixing one or more carbon-based materials and a binder among carbon materials and carbon composites;

[0017] A step of preparing a solid electrolyte layer with an intermediate layer formed thereon by applying and drying the above-mentioned composition for forming an intermediate layer on one surface of the solid electrolyte to cover 30% to 99.9% of the total surface area;

[0018] A step of contacting one or more electrolytes selected from a liquid electrolyte, a gel electrolyte, and a polymer electrolyte onto the surface of a solid electrolyte layer on which the intermediate layer is not formed;

[0019] A step of disposing of a cathode layer on one side of a solid electrolyte layer having the above-mentioned intermediate layer formed thereon and on one side of a solid electrolyte layer in contact with one or more electrolytes among a liquid electrolyte, a gel electrolyte, and a polymer electrolyte; and

[0020] A method for manufacturing a lithium metal battery is provided, comprising the step of manufacturing a lithium metal battery by placing an anode layer on the other side of a solid electrolyte layer on which the above-mentioned cathode layer is placed.

[0021] Depending on another aspect of work,

[0022] A negative electrode layer comprising lithium metal or lithium alloy;

[0023] A solid electrolyte layer disposed on the above cathode layer; and

[0024] A positive electrode layer disposed on the solid electrolyte layer; comprising

[0025] The region including an intermediate layer and a region not including an intermediate layer are further included between the above cathode layer and the above solid electrolyte layer.

[0026] The region including the above intermediate layer includes an intermediate layer including a carbon material, and

[0027] A lithium metal battery module is provided that includes a lithium metal battery as a unit cell, wherein at least a portion of the region not including the above intermediate layer includes one or more electrolytes selected from liquid electrolyte, gel electrolyte, and polymer electrolyte. Effects of the invention

[0028] A lithium metal battery according to one aspect comprises a negative electrode layer, a solid electrolyte layer, and a positive electrode layer. It further comprises a region including an intermediate layer and a region not including an intermediate layer between the negative electrode layer and the solid electrolyte layer. The region including the intermediate layer includes an intermediate layer including a carbon material, and at least a portion of the region not including the intermediate layer includes one or more electrolytes selected from a liquid electrolyte, a gel electrolyte, and a polymer electrolyte. The lithium metal battery has low charge transfer resistance between the solid electrolyte layer and the negative electrode layer, and can improve limiting current density and capacity per area. Brief explanation of the drawing

[0029] FIG. 1a is a structure of a negative electrode layer / intermediate layer / solid electrolyte layer of a lithium metal battery in an initial or fully discharged state according to one embodiment. FIG. 1b is a negative electrode layer / intermediate layer / solid electrolyte layer structure of a lithium metal battery in an initial or fully discharged state according to another embodiment. Figure 2 is a Nyquist plot showing the results of electrochemical impedance experiments for the lithium metal batteries prepared in Example 1, Example 2, and Comparative Example 1. Figure 3a shows the charge / discharge test results of the lithium metal battery prepared in Example 1. Figure 3b shows the charge / discharge test results of the lithium metal battery prepared in Example 2. Figure 3c shows the charge / discharge test results of the lithium metal battery prepared in Comparative Example 1. Specific details for implementing the invention

[0030] The present inventive concept described below is subject to various modifications and may have various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present inventive concept to specific embodiments and should be understood to include all modifications, equivalents, or substitutions that fall within the scope of the description of the present inventive concept.

[0031] The terms used below are for the purpose of describing specific embodiments only and are not intended to limit the creative concept. Singular expressions include plural expressions unless the context clearly indicates otherwise.

[0032] In this specification, expressions such as “at least one,” “one or more,” or “one or more” preceding components are to supplement the list of all components and do not mean that they are to supplement the individual components described above. In this specification, the term “combination” includes mixtures, alloys, reaction products, etc., unless specifically stated otherwise. In this specification, the term “include” means that, unless specifically stated otherwise, it does not exclude other components but may include additional components. In this specification, terms such as “first,” “second,” etc., do not indicate order, quantity, or importance, but are used to distinguish one element from another. Unless otherwise indicated in this specification or clearly contradicted by the context, they should be interpreted to include both singular and plural forms. “Or” means “and / or” unless otherwise specified.

[0033] Throughout this specification, terms such as “one embodiment,” “an embodiment,” etc., mean that specific elements described in relation to an embodiment are included in at least one embodiment described herein and may or may not be present in other embodiments. Furthermore, it should be understood that the described elements may be combined in any appropriate manner in various embodiments.

[0034] Unless otherwise stated, all percentages, parts, ratios, etc. are based on weight. Also, if a quantity, concentration, or other value or parameter is given as a range, a preferred range, or a list of preferred upper and lower limits, this should be understood as specifically disclosing any range formed from any pair of any upper limit or preferred value and any lower limit or preferred value, regardless of whether the range is disclosed separately.

[0035] Where a range of numerical values ​​is mentioned in this specification, unless otherwise stated, the range is intended to include its endpoint and all integers and fractions within that range. The scope of the invention is not intended to be limited to the specific values ​​mentioned when defining the range.

[0036] Unless otherwise specified, the unit “parts by weight” refers to the weight ratio between each component, and the unit “parts by mass” refers to the value obtained by converting the weight ratio between each component into solid content.

[0037] As used herein, “about” means within an acceptable range of deviation from a specific value determined by a person skilled in the art, taking into account errors related to the measurement and the measurement of a specific amount, including the mentioned value (i.e., the limits of the measurement system). For example, “about” may mean within one or more standard deviations, or within ± 30%, 20%, 10%, or 5% of the specified value.

[0038] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as generally understood by those skilled in the art to which this disclosure pertains. Furthermore, it will also be understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with that meaning in the relevant technology and this disclosure, and should not be interpreted as idealized or overly formal.

[0039] Exemplary embodiments are described herein with reference to cross-sectional views, which are schematic diagrams of idealized embodiments. Accordingly, the shape of the examples may vary, for example, as a result of manufacturing techniques and / or tolerances. Accordingly, the embodiments described herein should not be interpreted as being limited to the specific shape of the regions described herein and should include variations in shape that occur, for example, during the manufacturing process. For example, regions that are exemplified or described as flat may generally have rough and / or non-linear features. Also, exemplified acute angles may be rounded. Accordingly, regions exemplified in the drawings are by nature schematic, and their shapes are not intended to exemplify the exact shape of the regions or to limit the scope of the claims.

[0040] Generally, lithium metal batteries are manufactured using cold isostatic pressing (CIP) and / or warm isostatic pressing (WIP) through a pressurization step and a heat treatment step. As a result, all interface regions between the negative electrode layer and the solid electrolyte layer cannot maintain good contact, leading to the existence of a gap region or void between the negative electrode layer and the solid electrolyte layer. Consequently, the charge and discharge characteristics of the lithium metal battery are degraded.

[0041] Furthermore, oxide solid electrolytes have brittle characteristics. Therefore, if lithium metal batteries containing oxide solid electrolytes are manufactured using CIP and / or WIP, such lithium metal batteries are easily damaged.

[0042] The inventor of the present invention intends to solve the aforementioned problems and propose a lithium metal battery of a novel structure usable in various solid electrolyte layers including oxide-based solid electrolytes, a method for manufacturing the same, and a lithium metal battery module comprising the lithium metal battery as a unit cell.

[0044] A lithium metal battery, a method for manufacturing the same, and a lithium metal battery module including the lithium metal battery as a unit cell will be described in more detail below by way of exemplary embodiments.

[0046] lithium metal battery

[0047] A lithium metal battery according to one embodiment comprises a negative electrode layer comprising lithium metal or a lithium alloy, a solid electrolyte layer disposed on the negative electrode layer, and a positive electrode layer disposed on the solid electrolyte layer, and further comprises a region comprising an intermediate layer and a region not comprising an intermediate layer between the negative electrode layer and the solid electrolyte layer, wherein the region comprising the intermediate layer comprises an intermediate layer comprising a carbon material, and at least a portion of the region not comprising an intermediate layer comprises one or more electrolytes selected from a liquid electrolyte, a gel electrolyte, and a polymer electrolyte.

[0048] According to one embodiment, the region not including the intermediate layer may be an edge region between the cathode layer and the solid electrolyte layer, a region where the intermediate layer is not located other than the edge region, or a region of all of these.

[0049] A lithium metal battery according to one embodiment has low charge transfer resistance between the solid electrolyte layer and the negative electrode layer, and can improve limiting current density and capacity per area.

[0050] FIG. 1a is a negative electrode layer / intermediate layer / solid electrolyte layer structure (10) of a lithium metal battery in an initial or fully discharged state according to one embodiment. FIG. 1b is a negative electrode layer / intermediate layer / solid electrolyte layer structure (10') of a lithium metal battery in an initial or fully discharged state according to another embodiment.

[0051] Referring to FIG. 1a and FIG. 1b, the negative electrode layer / intermediate layer / solid electrolyte layer structure (10, 10') of a lithium metal battery comprises, in an initial or fully discharged state, a negative electrode layer (1, 1') composed of a negative electrode current collector (1a, 1'a) and a lithium metal layer or lithium alloy layer (1b, 1'b), a solid electrolyte layer (3, 3'), and an intermediate layer (2, 2') disposed between them.

[0052] According to an exemplary embodiment, the negative electrode current collector (1a, 1'a) is composed of a material that does not react with lithium, that is, does not form either an alloy or a compound. The material constituting the negative electrode current collector (1a, 1a') may be, for example, copper (Cu), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), and nickel (Ni), but is not necessarily limited to these, and any material used as an electrode current collector in the relevant technical field is acceptable. The thickness of the negative electrode current collector (1a, 1a') may be, for example, 1 μm to 50 μm, 1 μm to 40 μm, 1 μm to 30 μm, 1 μm to 20 μm, or 1 μm to 10 μm. The negative electrode current collector (1a, 1a') may be composed of one of the metals described above, or may be composed of an alloy of two or more metals or a coating material. The negative current collector (21) is, for example, in the form of a plate or foil.

[0053] A lithium metal layer or lithium alloy layer (1b, 1'b) according to an exemplary embodiment acts as a lithium reservoir because it is a metal layer containing lithium. The lithium alloy layer is not limited to a layer containing an element capable of forming an alloy with lithium, but may be, for example, an alloy such as a Li-Al alloy, a Li-Sn alloy, a Li-In alloy, a Li-Ag alloy, a Li-Au alloy, a Li-Zn alloy, a Li-Ge alloy, or a Li-Si alloy. The lithium metal layer or lithium alloy layer (1b, 1'b) may be composed of lithium metal alone, one of the alloys described above, or a combination of the alloys described above.

[0054] The thickness of the lithium metal layer or lithium alloy layer (1b, 1'b) according to an exemplary embodiment is not limited, but may be, for example, 1 μm to 200 μm, 1 μm to 150 μm, 1 μm to 100 μm, 1 μm to 50 μm, 1 μm to 40 μm, 1 μm to 30 μm, or 1 μm to 20 μm. If the thickness of the lithium metal layer or lithium alloy layer (1b, 1'b) is excessively thin, it is difficult for the lithium metal layer or lithium alloy layer (1b, 1'b) to perform the role of a lithium storage tank. If the thickness of the lithium metal layer or lithium alloy layer (1b, 1'b) is excessively thick, the mass and volume of the lithium metal battery increase, and there is a possibility that the cycle characteristics may deteriorate. The lithium metal layer or lithium alloy layer (1b, 1'b) may be, for example, a lithium metal foil having a thickness in this range.

[0055] A solid electrolyte layer (3, 3') according to an exemplary embodiment may be an oxide-based solid electrolyte, a polymer solid electrolyte, a polymer and inorganic hybrid electrolyte, or an organic and inorganic hybrid polymer electrolyte, or a combination thereof.

[0056] An oxide-based solid electrolyte according to an exemplary embodiment is a garnet-based ceramic Li 3+x La3M2O 12 (M=Te, Nb, or Zr) (x is an integer from 1 to 10), Li 1+x+y Al x Ti 2-x Si y P 3-y O 12 (0 <x<2, 0≤y<3), 리튬포스페이트(Li3PO4), 리튬티타늄포스페이트(Li x Ti y (PO4)3, 0 <x<2, 0<y<3), 리튬알루미늄티타늄포스페이트 (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), 리튬게르마늄티오포스페이트(Li x Ge y P z S w , 0 <x<4, 0<y<1, 0<z<1, 0<w<5), 리튬나이트라이드계열 글래스(Li x N y , 0 <x<4, 0<y<2), SiS2(Li x Si y S z , 0 <x<3,0<y<2, 0<z<4), P2S5계열 글래스(Li x P y S z , 0 <x<3, 0<y<3, 0<z<7), Li2O, LiF, LiOH, Li2CO3, LiAlO2, Li2O-Al2O3-SiO2-P2O5-TiO2-GeO2계 세라믹스, 및 LiBSiO 중에서 선택된 하나 이상 또는 이들의 조합물인 것일 수 있다.

[0057] Oxide-based solid electrolytes can be manufactured by sintering, casting, etc.

[0058] For example, oxide-based solid electrolytes can be garnet-based solid electrolytes.

[0059] For example, a garnet-based solid electrolyte may include an oxide represented by the following chemical formula 1.

[0060] [Chemical Formula 1]

[0061] (Li x M1 y )(M2) 3-δ (M3) 2-ω O 12-z X z

[0062] In Chemical Formula 1, 6≤x≤8, 0≤y<2, -0.2≤δ≤0.2, -0.2≤ω≤0.2, 0≤z≤2,

[0063] M1 is a monovalent cation, a divalent cation, a trivalent cation, or a combination thereof, and

[0064] M2 is a monovalent cation, a divalent cation, a trivalent cation, or a combination thereof, and

[0065] M3 is a monovalent cation, divalent cation, trivalent cation, tetravalent cation, pentavalent cation, hexavalent cation, or a combination thereof, and

[0066] X is a monovalent, divalent, or trivalent anion or a combination thereof.

[0067] In the above chemical formula 1, examples of monovalent cations include Na, K, Rb, Cs, H, Fr, etc., and examples of divalent cations include Mg, Ca, Ba, Sr, etc. Examples of trivalent cations include In, Sc, Cr, Au, B, Al, Ga, etc., and examples of tetravalent cations include Sn, Ti, Mn, Ir, Ru, Pd, Mo, Hf, Ge, V, Si, etc. And examples of pentavalent cations include Nb, Ta, Sb, V, P, etc.

[0068] M1 is, for example, hydrogen (H), iron (Fe), gallium (Ga), aluminum (Al), boron (B), beryllium (Be), or a combination thereof. M2 is La (lanthanum), barium (Ba), calcium (Ca), strontium (Sr), yttrium (Y), bismuth (Bi), praseodymium (Pr), neodymium (Nd), actinium (Ac), samarium (Sm), galolinium (Gd) or a combination thereof, and M3 is zirconium (Zr), hafnium (Hf), tin (Sn), niobium (Nb), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), molybdenum (Mo), tungsten (W), tantalum (Ta), magnesium (Mg), technetium (Tc), ruthenium (Ru), palladium (Pd), iridium (Ir), scandium (Sc), cadmium (Cd), indium (In), antimony (Sb), tellurium (Te), It is thallium (Tl), platinum (Pt), silicon (Si), aluminum (Al), or a combination thereof.

[0069] In the above Chemical Formula 1, the monovalent anion used as X is a halogen atom, a pseudohalogen, or a combination thereof, and the divalent anion is S 2- , or Se 2- And, the trivalent anion is, for example, N 3- am.

[0070] In Chemical Formula 1, 6.6≤x≤8, 6.7≤x≤7.5, or 6.8≤x≤7.1.

[0071] For example, a garnet-based solid electrolyte may include an oxide represented by the following chemical formula 2.

[0072] [Chemical Formula 2]

[0073] (Li x M1 y )(La a1 M2 a2 ) 3-δ (Zr b1 M3 b2 ) 2- O 12-z X z

[0074] In Chemical Formula 2, M1 is hydrogen (H), iron (Fe), gallium (Ga), aluminum (Al), boron (B), beryllium (Be), or a combination thereof, and

[0075] M2 is barium (Ba), calcium (Ca), strontium (Sr), yttrium (Y), bismuth (Bi), praseodymium (Pr), neodymium (Nd), actinium (Ac), samarium (Sm), galolinium (Gd), or a combination thereof, and

[0076] M3 is hafnium (Hf), tin (Sn), niobium (Nb), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), molybdenum (Mo), tungsten (W), tantalum (Ta), magnesium (Mg), technetium (Tc), ruthenium (Ru), palladium (Pd), iridium (Ir), scandium (Sc), cadmium (Cd), indium (In), antimony (Sb), tellurium (Te), thallium (Tl), platinum (Pt), silicon (Si), aluminum (Al), or a combination thereof,

[0077] 6≤x≤8, 0≤y<2, -0.2≤δ≤ 0.2, -0.2≤ω≤0.2, 0≤z≤2,

[0078] a1+a2=1, 0 <a1≤1, 0≤a2<1,

[0079] b1+b2=1, 0 <b1≤1, 0≤b2<1,

[0080] X is a monovalent anion, a divalent anion, a trivalent anion, or a combination thereof.

[0081] In the above chemical formula 2, the monovalent anion used as X is a halogen atom, a pseudohalogen, or a combination thereof, and the divalent anion is S 2- , or Se 2- And, the trivalent anion is, for example, N 3- am.

[0082] In Chemical Formula 2, 6.6≤x≤8, 6.7≤x≤7.5, or 6.8≤x≤7.1.

[0083] In this specification, "pseudohalogen" refers to a molecule composed of two or more electronegative atoms that resemble halogens in the free state and generate anions similar to halide ions. Examples of pseudohalogens are cyanides, cyanates, thiocyanates, azides, or combinations thereof.

[0084] Halogen atoms are, for example, iodine (I), chlorine (Cl), bromine (Br), fluorine (F), or combinations thereof, and pseudohalogens are, for example, cyanide, cyanate, thiocyanate, azide, or combinations thereof.

[0085] Trivalent anions are, for example, N 3- am.

[0086] In the above chemical formula 1, Al, Ga, In, Si, Ge, Sn, Sb, Bi, Sc, Y, Ti, Hf, V, Nb, Ta, W, or a combination thereof.

[0087] According to another embodiment, the garnet-based solid electrolyte may be an oxide represented by the following chemical formula 3.

[0088] [Chemical Formula 3]

[0089] Li 3+x La3Zr 2-a M a O 12

[0090] In Chemical Formula 3, M is Al, Ga, In, Si, Ge, Sn, Sb, Bi, Sc, Y, Ti, Hf, V, Nb, Ta, W, or a combination thereof, x is a number from 1 to 10, and 0≤a<2.

[0091] Garnet-based solid electrolytes are, for example, Li7La3Zr2O 12 , Li6.5 La3Zr 1.5 Ta 0.5 O 12 You can lift the back.

[0092] Garnet-based solid electrolytes have an ionic conductivity of 1 mS·cm -1 The above can be manufactured in the form of pellets, tapes, films, etc. Garnet-based solid electrolytes can be manufactured to have various thicknesses over a wide temperature range.

[0093] Examples of polymer solid electrolytes according to exemplary embodiments may include polyethylene oxide, polypropylene oxide, polystyrene (PS), polyphosphogen, polysiloxane, polyvinylidene fluoride-co-hexafluoropropylene (PVDF-co-HFP), polyacrylonitrile (PAN), or combinations thereof. The ionic conductivity of such polymer solid electrolytes may be achieved through local segmental motion of the polymers. Polymer solid electrolytes may be prepared by mixing polyethers with plasticizer salts, sometimes with a small amount of liquid plasticizer. Thin films of such electrolytes may be prepared by solvent evaporation coating. However, they are not limited thereto, and any polymer solid electrolyte available in the art may be used.

[0094] In polymer-inorganic hybrid electrolytes, inorganic materials act as fillers that disrupt the regularity of polymer chains; however, they can also be utilized as "active" fillers because a large number of lithium ions can move rapidly along the interface between the polymer and inorganic fillers. Examples of such inorganic materials include Al2O3, TiO2, and SiO2. The inorganic materials of the aforementioned examples can be used as polymer-inorganic hybrid electrolytes in various sizes and morphologies.

[0095] Examples of organic and inorganic hybrid polymer electrolytes include, but are not limited to, electrolytes of alkoxysilane inorganic materials and triazine-based organic materials based on polyether diamines, and any organic and inorganic hybrid polymer electrolyte available in the relevant technical field may be used. Such organic and inorganic hybrid polymer electrolytes can improve high ionic conductivity, Coulomb efficiency, initial discharge capacity, and lifespan characteristics.

[0096] According to an exemplary embodiment, the solid electrolyte layer (3, 3') may include pores on its surface. The pores on the surface of the solid electrolyte layer (3, 3') may be formed by surface treatment. A component of the intermediate layer (2, 2') described later may be filled into some or all of the pores on the surface of the solid electrolyte layer (3, 3'). Examples of such a component include carbon materials. When the component of the intermediate layer (2, 2') penetrates into some or all of the pores on the surface of the solid electrolyte layer (3, 3'), not only is the contact area between the intermediate layer (2, 2') and the solid electrolyte layer (3, 3') increased, but strong interlayer bonding may also occur.

[0097] An intermediate layer (2, 2') according to an exemplary embodiment may include a carbon material. The intermediate layer (2, 2') may include one or more carbon-based materials and a binder among carbon materials and carbon composites.

[0098] The carbon material may be a porous carbon material or a non-porous carbon material. The carbon material may be a three-dimensional carbon material particle. The carbon material may include, for example, carbon black particles, graphite particles, carbon nanoflowers, carbon nanoprisms, carbon nanodiamonds, or combinations thereof. These three-dimensional carbon material particles may or may not form pores. For example, the three-dimensional carbon material particles may form pores.

[0099] The carbon composite may be a composite of a carbon material and a metal material. For example, the metal material may include one or more selected from iron (Fe), platinum (Pt), cobalt (Co), cadmium (Cd), copper (Cu), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), zinc (Zn), nickel (Ni), silver (Ag), gold (Au), palladium (Pd), rubidium (Ru), osmium (Os), molybdenum (Mo), zirconium (Zr), niobium (Nb), lanthanum (La), indium (In), tin (Sn), lead (Pb), and bismuth (Bi). Since such a carbon composite may have excellent electrical conductivity and a high specific surface area, the charge and discharge characteristics of the lithium metal battery may be further improved.

[0100] The metal material may, for example, have a particle form. The average particle size (D50) of the metal material may be about 4 μm or less, about 3 μm or less, about 2 μm or less, about 1 μm or less, or 0.5 μm or less. The lower limit of the average particle size (D50) is not specifically limited, but may be about 10 nm or more. The average particle size (D50) refers to the value of the particle size corresponding to 50% of the smallest particle when the total number of particles is set to 100% in a distribution curve in which particles are accumulated in order from the smallest particle to the largest particle. The average particle size (D50) may be measured by methods widely known to those skilled in the art, for example, by measuring with a particle size analyzer, or by measuring from a TEM image or an SEM image. Alternatively, the average particle size (D50) can be easily obtained by using a measuring device utilizing dynamic light scattering, performing data analysis to count the number of particles for each particle size range, and then calculating from this.

[0101] The weight ratio of the carbon material and the metal material in the carbon composite is, for example, 10:1 to 1:10, 5:1 to 1:5, 4:1 to 1:4, 3:1 to 1:3, or 2:1 to 1:2, but is not necessarily limited to these ranges and can be selected according to the required characteristics of the lithium metal battery.

[0102] The carbon-based material described above provides a lithium atom transport pathway from the solid electrolyte layer (3,3') to the negative electrode layer (1,1'). The porous carbon-based material has pores that are partially or entirely filled with lithium, and can rapidly supply and remove lithium from the solid electrolyte layer (3,3') to the negative electrode layer (1,1') by diffusion. As a result, the lithium metal battery can have an improved discharge capacity. In addition, the lithium metal battery can improve battery performance by reinforcing the mechanical structure between the solid electrolyte layer (3,3') and the negative electrode layer (1,1') even when using less binder.

[0103] The intermediate layer (2, 2') according to an exemplary embodiment may further include a binder. The binder may be a water-based binder, an organic binder, or a combination thereof.

[0104] The water-based binder has low reactivity and serves to improve the binding strength with the solid electrolyte layer (3, 3'). In addition, the water-based binder can reduce the binder content due to its excellent binding strength with the solid electrolyte layer (3, 3') and is environmentally friendly because it uses water as a solvent.

[0105] For example, the aqueous binder may include one or more polymers selected from polyvinyl alcohol, polyacrylic acid, polymethacrylic acid, polyvinyl alcohol-grafted polyacrylic acid, polyvinyl alcohol-grafted polymethacrylic acid, and carboxymethylcellulose, or copolymers thereof. Among these, one or more polymers selected from polyvinyl alcohol-grafted polyacrylic acid and polyvinyl alcohol-grafted polymethacrylic acid, or copolymers thereof, may be used as the aqueous binder. Such grafted polymer or copolymer binders not only have improved binding strength compared to linear polymers or copolymers but also possess superior elasticity. Therefore, a lithium metal battery containing a polymer or copolymer grafted onto an intermediate layer (2, 2') as a binder can have improved charge / discharge characteristics.

[0106] The content of the aqueous binder may be 0.1% to 7% by weight based on 100% by weight of the entire intermediate layer (2, 2'). Even with the use of such a low amount of binder, the bonding strength between the solid electrolyte layer (3, 3') and the negative electrode layer (1, 1') is improved, and the battery performance can be improved by having a strong mechanical structure.

[0107] For example, the organic binder may include one or more polymers selected from butadiene rubber, nitrile-butadiene rubber, hydrogenated nitrile-butadiene rubber, styrene-butadiene rubber, styrene-butadiene-styrene rubber, acrylate-butadiene rubber, acrylonitrile-butadiene-styrene rubber, polyvinylidene fluoride, vinylidene fluoride and hexafluoropropylene copolymer, polyisobutylene, polyethylene, polypropylene, and polyimide, or copolymers thereof.

[0108] Optionally, the intermediate layer (2, 2') may further include an electrically conductive polymer.

[0109] Examples of the above electrically conductive polymers include poly(fluorene), polyphenylene, polypyrene, polyazulene, polynaphthalene, polyacetylene (PAC), poly(p-phenylenevinylene) (PPV), polypyrrole (PPY), polycarbazole, polyindole, polyazepine, polyaniline (PANI), polythiophene (PT), poly(3,4-ethylenedioxythiophene) (PEDOT), or poly(p-phenylene sulfide) (PPS). If the intermediate layer (2, 2') further includes an electrically conductive polymer, the charge and discharge characteristics of the battery can be further improved.

[0110] The thickness of the intermediate layer (2, 2') may be 1 μm to 30 μm. For example, the thickness of the intermediate layer (2, 2') may be 1 μm to 28 μm, 1 μm to 26 μm, 1 μm to 24 μm, 1 μm to 22 μm, 1 μm to 20 μm, 1 μm to 18 μm, 1 μm to 16 μm, 1 μm to 14 μm, 1 μm to 12 μm, or 1 μm to 12 μm. The intermediate layer (2, 2') can prevent a decrease in energy density within the above thickness range.

[0111] According to one embodiment, the intermediate layer (2, 2') may have a horizontal length shorter than the horizontal length of the cathode layer (1, 1') and the solid electrolyte layer (3, 3').

[0112] According to one embodiment, the area of ​​the intermediate layer (2, 2') may be smaller than the area of ​​the cathode layer (1, 1').

[0113] For example, the area of ​​the intermediate layer (2, 2') may be 30% to 80% based on 100% of the total surface area of ​​the solid electrolyte layer (3, 3'). For example, the area of ​​the intermediate layer (2, 2') may be 40% to 80% or 50% to 80% based on 100% of the total surface area of ​​the solid electrolyte layer (3, 3').

[0114] An interlayer-free region may exist on one or both edges of the intermediate layer (2, 2').

[0115] In one embodiment, an intermediate layer may not be included in a region, for example, an interface edge region between a cathode layer (1, 1') and a solid electrolyte layer (3, 3'), a region other than the edge region where an intermediate layer is not located, or one or more electrolytes selected from a liquid electrolyte, a gel electrolyte, and a polymer electrolyte may be included in all of these regions.

[0116] Liquid electrolytes and gel electrolytes according to an exemplary embodiment may include ionic liquid compounds and lithium salts.

[0117] The ionic liquid compound comprises i) one or more cations selected from ammonium, pyrrolidinium, pyridinium, pyrimidinium, imidazolium, piperidinium, pyrazolium, oxazolium, pyridazinium, phosphonium, sulfonium, triazole, and mixtures thereof, and ii) BF4-, PF6-, AsF6-, SbF6-, AlCl4-, HSO4-, ClO4-, CH3SO3-, CF3CO2-, (CF3SO2)2N-, Cl-, Br-, I-, BF4-, SO4 - , PF6-, ClO4-, CF3SO3-, CF3CO2-, (C2F5SO2)2N-, (C2F5SO2)(CF3SO2)N-, NO3 - , Al2Cl7 - , AsF6 - , SbF6 - , CF3COO - , CH3COO - , CF3SO3 - , (CF3SO2)3C - , (CF3CF2SO2)2N - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , SF5CF2SO3 - , SF5CHFCF2SO3 -, CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C - , (O(CF3)2C2(CF3)2O)2PO - It may be selected from ionic liquid compounds containing one or more anions selected from and (CF3SO2)2N-.

[0118] For example, the ionic liquid compound may be one or more selected from the group consisting of N-methyl-N-propyl-pyrrolidinium bis(trifluoromethylsulfonyl)imide, N-methyl-N-propyl-pyrrolidinium (fluorosulfonyl)imide, N-butyl-N-methyl-pyrrolidinium bis(3-trifluoromethylsulfonyl)imide, N-butyl-N-methyl-pyrrolidinium bis(3-fluorosulfonyl)imide, 1-butyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide, and 1-ethyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide.

[0119] For example, ionic liquid compounds include [emim]Cl / AlCl3(emim ethyl methyl imidazolium), [bmpyr]NTf2(bppyr = butyl methyl pyridinium), [bpy]Br / AlCl3(bpy = 4, 4'-bipyridine), [choline]Cl / CrCl3·6H2O, [Hpy(CH2)3pyH][NTf2]2(py = pyridinium, NTf = trifluoromethanesulfonimide), [emim]OTf / [hmim]I(hmim = hexyl methyl imidazolium), [choline]Cl / HOCH2CH2OH, [Et2MeN(CH2CH2OMe)]BF4(Et = ethyl, Me = methyl, Pr = propyl, Bu = butyl, Ph = phenyl, Oct = octyl, Hex = hexyl), [Bu3PCH2CH2C8F 17]OTf(OTf = trifluoromethane sulfonate), [bmim]PF6(bmim = butyl methyl imidazolium), [bmim]BF4, [omim]PF6(omim = octyl methyl imidazolium), [Oct3PC 18 H 37 ]I, [NC(CH2)3mim]NTf2(mim = methyl imidazolium), [Pr4N][B(CN)4], [bmim]NTf2, [bmim]Cl, [bmim][Me(OCH2CH2)2OSO3], [PhCH2mim]OTf, [Me3NCH(Me)CH(OH)Ph] NTf2, [pmim][(HO)2PO2] (pmim = propyl methyl imidazolium), [b(6-Me)quin]NTf2(bquin = butyl quinolinium, [bmim][Cu2Cl3], [C 18 H 37 OCH2mim]BF4(mim = methyl imidazolium), [heim]PF6(heim = hexyl ethyl imidazolium), [mim(CH2CH2O)2CH2CH2mim][NTf2]2(mim = methyl imidazolium), [obim]PF6(obim = octyl butyl imidazolium), [oquin]NTf2(oquin = octyl quinolinium), [hmim][PF3(C2F5)3], [C 14 H 29 mim]Br(mim = methyl imidazolium), [Me2N(C 12 H 25 )2]NO3, [emim]BF4, [mm(3-NO2)im][dinitrotriazolate] (mm(3-NO2)im = dimethyl-3-NO2-imidazolium), [MeN(CH2CH2OH)3], [MeOSO3], [Hex3PC 14 H 29]NTf2, [emim][EtOSO3], [choline][ibuprofenate], [emim]NTf2, [emim][(EtO)2PO2], [emim]Cl / CrCl2, [Hex3PC 14 H 29 ]N(CN) can be 2nd place.

[0120] The molecular weight of the ionic liquid compound may be, for example, 50 Dalton to 1500 Dalton, 50 Dalton to 1000 Dalton, 50 Dalton to 900 Dalton, 50 Dalton to 800 Dalton, or 50 Dalton to 700 Dalton or less. By having a molecular weight within this range, the ionic conductivity of the liquid electrolyte or gel electrolyte may be further improved.

[0121] The lithium salt has a concentration of 0.1 M to 5 M and may have one or more selected from LiPF6, LiBF4, LiCF3SO3, Li(CF3SO2)2N, Li(CF3SO2)3C, LiC2F5SO3, Li(FSO2)2N, LiC4F9SO3, LiN(SO2CF2CF3)2, LiN(CN)2, and compounds represented by chemical formulas 11 to 14.

[0122] [Chemical Formula 11] [Chemical Formula 12] [Chemical Formula 13] [Chemical Formula 14]

[0123] , , , .

[0124] A polymer electrolyte according to an exemplary embodiment may comprise a polymer or copolymer comprising an ion-conducting repeating unit and a lithium salt. The ion-conducting repeating unit is a unit having ion conductivity and may be, for example, an alkylene oxide unit, a hydrophilic unit, etc.

[0125] For example, the ion-conducting repeating unit may include ether monomers, acrylic monomers, methacrylate monomers, siloxane monomers, or combinations thereof. For example, a polymer containing an ion-conducting repeating unit may be polyethylene oxide, polypropylene oxide, polymethyl methacrylate, polyethyl methacrylate, polydimethylsiloxane, polyacrylic acid, polymethacrylic acid, polymethyl acrylate, polyethyl acrylate, polyethylhexyl acrylate, polybutyl methacrylate, poly2-ethylhexyl methacrylate, polydecyl acrylate, polyethylene vinyl acetate, or a combination thereof. The ion-conducting polymer may be, for example, polyethylene oxide (PEO), polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polyvinylsulfone, or a combination thereof.

[0126] Alternatively, the polymer electrolyte may comprise an ionic liquid polymer. The ionic liquid polymer comprises, for example, i) one or more cations selected from ammonium-based, pyrrolidinium-based, pyridinium-based, pyrimidinium-based, imidazolium-based, piperidinium-based, pyrazolium-based, oxazolium-based, pyridazinium-based, phosphonium-based, sulfonium-based, triazole-based, and mixtures thereof, and ii) BF4-, PF6-, AsF6-, SbF6-, AlCl4-, HSO4-, ClO4-, CH3SO3-, CF3CO2-, (CF3SO2)2N-, Cl-, Br-, I-, BF4-, SO4 - , PF6-, ClO4-, CF3SO3-, CF3CO2-, (C2F5SO2)2N-, (C2F5SO2)(CF3SO2)N-, NO3 - , Al2Cl7 - , AsF6 - , SbF6 - , CF3COO - , CH3COO - , CF3SO3 - , (CF3SO2)3C - , (CF3CF2SO2)2N - ,(CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , SF5CF2SO3 - , SF5CHFCF2SO3 - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C - , (O(CF3)2C2(CF3)2O)2PO - It may contain repeating units comprising one or more anions selected from and (CF3SO2)2N-. The ionic liquid polymer may be, for example, poly(diallyldimethylammonium)TFSI, poly(1-allyl-3-methylimidazolium trifluoromethanesulfonylimide), poly((N-methyl-N-propylpiperidinium bis(trifluoromethanesulfonyl)imide)), or a combination thereof.

[0127] A lithium metal battery according to one embodiment may include lithium cations in a region that does not include an intermediate layer (2, 2').

[0128] As a result, the lithium metal battery can have the electrolyte located in a region that does not include the intermediate layer (2, 2') and come into direct contact with lithium. As a result, the lithium metal battery has low charge transfer resistance between the solid electrolyte layer (3, 3') and the negative electrode layer (1, 1'), and the limiting current density and capacity per area can be improved.

[0129] A lithium metal battery according to one embodiment may include a lithium layer in part or all of the interface between an intermediate layer (2, 2') and a solid electrolyte layer (3, 3') during charging and discharging.

[0130] According to an exemplary embodiment, the anode layer may include an anode current collector and an anode active material layer.

[0131] The positive current collector may use a metal substrate. Examples of metal substrates may include aluminum (Al), indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), germanium (Ge), lithium (Li), or alloys thereof. The positive current collector may be in the form of a plate or a foil. The positive current collector may also be omitted.

[0132] Any cathode active material commonly used in lithium metal batteries may be used without restriction. For example, the cathode active material may be one or more composite oxides of lithium and a metal selected from cobalt, manganese, nickel, and combinations thereof; specific examples include Li a A 1-b B' b D'2(wherein 0.90 ≤ a ≤ 1.8, and 0 ≤ b ≤ 0.5); Li a E 1-b B' b O 2-c D' c (In the above formula, 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05); LiE 2-b B' b O 4-c D' c (In the above equation, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05); Li a Ni 1-b-c Co b B' c D' α (In the above equation, 0.90 ≤ a ≤ 1.8, 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 equation, 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'2(wherein, 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 equation, 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 equation, 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'2(wherein, 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(wherein 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 G e O2(in the above equation, 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 bO2(in the above equation, 0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1); Li a CoG b O2(in the above equation, 0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1); Li a MnG b O2(in the above equation, 0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1); Li a Mn2G b O4(wherein 0.90 ≤ a ≤ 1.8 and 0.001 ≤ b ≤ 0.1); QO2; QS2; LiQS2; V2O5; LiV2O2; LiI'O2; LiNiVO4; Li (3-f) J2(PO4)3(0 ≤ f ≤ 2); Li (3-f) A compound represented by any one of the chemical formulas of Fe2(PO4)3 (0 ≤ f ≤ 2); LiFePO4 may be used. 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; and J is V, Cr, Mn, Co, Ni, Cu, or a combination thereof. For example, the positive electrode active material may include one or more selected from lithium cobalt oxide, lithium nickel oxide, lithium nickel cobalt oxide, lithium nickel cobalt aluminum oxide, lithium nickel cobalt manganese oxide, lithium manganese oxide, lithium iron phosphate oxide, nickel sulfide, copper sulfide, lithium sulfide, iron oxide, and vanadium oxide. For example, the positive electrode active material may be LiCoO2, LiMn x O2(x=1, 2), LiNi 1-xMn x O 2x (0 <x<1), LiNi 1-x-y Co x Mn y It may be O2 (0≤x≤0.5, 0≤y≤0.5), LiFePO4, TiS2, FeS2, TiS3, or FeS3, etc.

[0133] The positive electrode active material layer may further include a positive electrode electrolyte. The positive electrode electrolyte may include an ionic liquid compound and a lithium salt. The ionic liquid compound may be non-volatile. The ionic liquid compound refers to a salt or a room temperature molten salt that is in a liquid state at room temperature and consists only of ions, having a melting point below room temperature.

[0134] The ionic liquid compound comprises a) one or more cations selected from ammonium, pyrrolidinium, pyridinium, pyrimidinium, imidazolium, piperidinium, pyrazolium, oxazolium, pyridazinium, phosphonium, sulfonium, triazolium, and mixtures thereof, and b) BF4 - , PF6 - , AsF 6- , SbF6 - , AlCl4 - , HSO4 - , ClO4 - , CH3SO3 - , CF3CO2 - , Cl - , Br - , I - , SO4 - , CF3SO3 - , (FSO2)2N - , (C2F5SO2)2N - , (C2F5SO2)(CF3SO2)N - , and (CF3SO2)2N -It may be one selected from compounds containing one or more anions selected from among. For example, the ionic liquid electrolyte may be one or more selected from N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide, N-butyl-N-methylpyrrolidinium bis(3-trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, and 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide.

[0135] The ionic liquid compound may have a viscosity of 50 cps to 500 cps. For example, the viscosity may be 50 cps to 450 cps, 70 cps to 400 cps, or 100 cps to 300 cps. Within this viscosity range, the lithium metal battery can ensure electrochemical stability during charging and discharging.

[0136] The ionic liquid compound may be filled into the pores of part or all of the surface of the solid electrolyte layer in contact with the positive electrode active material layer. The content of the ionic liquid compound may be 0.1 to 20 parts by weight, 0.1 to 15 parts by weight, 0.1 to 10 parts by weight, or 0.1 to 5 parts by weight per 100 parts by weight of the positive electrode active material layer that does not contain the ionic liquid compound. By including the ionic liquid compound, the ionic conductivity is further improved, and the charge / discharge characteristics of the lithium metal battery can be further improved.

[0137] The positive active material layer may further include a conductive material and a binder.

[0138] For example, the conductive material may include carbon black, carbon fiber, graphite, or a combination thereof. For example, the carbon black may be acetylene black, Ketjen black, Super P-carbon, Channel black, furnace black, lamp black, thermal black, or a combination thereof. The graphite may be natural graphite or synthetic graphite. A combination comprising at least one of the above may be used.

[0139] The positive electrode active material layer may additionally include a conductive material of a different composition in addition to the aforementioned conductive material. The additional conductive material may be an electrically conductive fiber such as a metal fiber; a fluorocarbon powder; a metal powder such as aluminum powder or nickel powder; a conductive whisker such as zinc oxide or potassium titanate; a polyethylene derivative; or a combination thereof. The content of the conductive material may be in the range of about 1 to about 10 parts by weight, for example, about 2 to about 7 parts by weight, based on 100 parts by weight of the positive electrode active material. When the amount of the conductive material is within this range, for example, about 1 to about 10 parts by weight, the electrical conductivity of the positive electrode layer may be appropriate.

[0140] A binder can improve adhesion between the components of the anode layer and adhesion to the anode current collector. Examples of binders may include polyacrylic acid (PAA), polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene monomer (EPDM), sulfonated EPDM, styrene-butadiene-rubber, fluorinated rubber, copolymers thereof, or combinations thereof. The content of the binder may be in the range of about 1 to about 10 parts by weight, for example, about 2 to about 7 parts by weight, based on 100 parts by weight of the positive active material. When the content of the binder is within this range, the adhesion of the positive active material layer to the positive current collector is further improved, and the decrease in energy density of the positive active material layer can be suppressed.

[0141] N-methylpyrrolidone, acetone, water, etc., may be used as solvents. The content of the cathode active material, conductive material, binder, and solvent is at levels typically used in lithium batteries.

[0142] In addition, a plasticizer may be added to the positive electrode active material layer, and pores may be formed inside the positive electrode active material layer.

[0143] A lithium metal battery according to one embodiment has a charge transfer resistance (R) by electrochemical impedance (EIS) analysis at 25 ℃.ct ) can be 240Ω to 200Ω. For example, the charge transfer resistance (R) by electrochemical impedance (EIS) analysis at 25 ℃ ct ) can be 220 Ω to 180 Ω or 200 Ω to 160 Ω.

[0144] A lithium metal battery according to one embodiment has a high discharge capacity and energy density. The shape of the lithium metal battery is not particularly limited and may be, for example, coin type, button type, sheet type, stacked type, cylindrical type, flat type, etc. In addition, the lithium metal battery can be applied to large batteries used in electric vehicles, etc. For example, the lithium metal battery can be used in hybrid vehicles such as plug-in hybrid electric vehicles (PHEV). In addition, the lithium metal battery can be used in fields requiring a large amount of power storage, and for example, can be used in electric bicycles or power tools.

[0146] Method for manufacturing a lithium metal battery

[0147] A method for manufacturing a lithium metal battery according to one embodiment may include: a step of preparing a composition for forming an intermediate layer by mixing one or more carbon-based materials and a binder among carbon materials and carbon composites; a step of preparing a solid electrolyte layer with an intermediate layer formed by applying and drying the composition for forming an intermediate layer to one surface of a solid electrolyte at a rate of 30% to 99.9% based on the total surface area; a step of contacting one or more electrolytes among a liquid electrolyte, a gel electrolyte, and a polymer electrolyte to the surface of the solid electrolyte layer where the intermediate layer is not formed; a step of placing a negative electrode layer on one surface of the solid electrolyte layer where the one surface of the solid electrolyte layer with the intermediate layer formed and one or more electrolytes among the liquid electrolyte, a gel electrolyte, and a polymer electrolyte are in contact; and a step of manufacturing a lithium metal battery by placing a positive electrode layer on the other surface of the solid electrolyte layer where the negative electrode layer is placed.

[0148] A method for manufacturing a lithium metal battery according to one embodiment can provide a lithium metal battery with a robust mechanical structure, low charge transfer resistance between a solid electrolyte layer and a negative electrode layer, and improved limiting current density and capacity per area, without using cold isostatic pressing (CIP) and / or warm isostatic pressing (WIP).

[0149] First, a composition for forming an intermediate layer is prepared by mixing one or more carbon-based materials and a binder among carbon materials and carbon composites. The composition for forming an intermediate layer may include one or more carbon-based materials among carbon materials and carbon composites, a binder, and a solvent. The binder may be a water-based binder or an organic-based binder, or a combination thereof. The content of the binder may be 0.1 to 10 parts by weight, 0.1 to 7 parts by weight, or 0.1 to 5 parts by weight based on 100 parts by weight of the composition for forming an intermediate layer.

[0150] The solvent may include water, deionized water, or organic solvents. Examples of organic solvents include alcohol-based solvents such as ethanol, propanol, butanol, 1,5-pentanediol, and 1-methylamino-2,3-propanediol; lactone-based solvents such as ε-caprolactone and α-acetyl γ-butyrolactone; glycol-based solvents such as diethylene glycol, 1,3-butylene glycol, and propylene glycol; glycol ether-based solvents such as triethylene glycol dimethyl ether, tripropylene glycol dimethyl ether, and diethylene glycol monobutyl ether; and carbonate-based solvents such as propylene carbonate and ethylene carbonate; N-methylpyrrolidone (NMP) solvent; dimethylformamide (DMF) solvent; acetone solvent; dimethylacetamide solvent, etc. The above-described solvents may be used alone or in a mixture of two or more.

[0151] Next, a solid electrolyte molded body is prepared. The solid electrolyte molded body can be manufactured, for example, by heat-treating a solid electrolyte material, specifically a precursor of an oxide-based solid electrolyte material.

[0152] Oxide-based solid electrolytes can be manufactured by contacting precursors in stoichiometric amounts to form a mixture and heat-treating the mixture.

[0153] Contact may include milling or grinding, such as ball milling, for example. A mixture of precursors mixed in a stoichiometric composition may be subjected to primary heat treatment in an oxidizing atmosphere to prepare a primary heat treatment product.

[0154] The first heat treatment can be performed for 1 to 36 hours at a temperature range of 1000 ℃ or lower. The product of the first heat treatment can be ground.

[0155] Grinding of the product of the first heat treatment can be performed dry or wet.

[0156] Wet grinding can be performed, for example, by mixing the primary heat treatment product with a solvent such as methanol and then milling it for 0.5 to 10 hours using a ball mill or the like.

[0157] Dry grinding can be performed by milling with a ball mill or the like without a solvent. The particle size of the ground primary heat treatment product can be 0.1 μm to 10 μm or 0.1 μm to 5 μm. The ground primary heat treatment product can be dried.

[0158] The pulverized primary heat treatment product may be mixed with a binder solution and formed into pellets, or simply pressed with a pressure of 1 ton to 10 ton to form pellets. The molded body may be subjected to secondary heat treatment at a temperature of less than 1000 ℃ for 1 hour to 36 hours. Through the secondary heat treatment, a solid electrolyte molded body (11) which is a sintered product is obtained. The secondary heat treatment may be performed, for example, at 550 ℃ to 1000 ℃. The primary heat treatment time may be 1 hour to 36 hours. To obtain the sintered product, the secondary heat treatment temperature is higher than the primary heat treatment temperature. For example, the secondary heat treatment temperature may be 10 ℃ or higher, 20 ℃ or higher, 30 ℃ or higher, or 50 ℃ or higher than the primary heat treatment temperature. The molded article may be subjected to a secondary heat treatment in one or more of an oxidizing atmosphere and a reducing atmosphere. The secondary heat treatment may be performed in a) an oxidizing atmosphere, b) a reducing atmosphere, or c) an oxidizing atmosphere and a reducing atmosphere.

[0159] Alternatively, oxide-based solid electrolytes can be manufactured using a tape casting method. For example, oxide-based solid electrolyte powder is mixed with a binder and a solvent to prepare an oxide solid electrolyte slurry. The oxide solid electrolyte slurry is ball-milled for 12 to 24 hours and aged for 1 to 4 hours. The aged oxide solid electrolyte slurry is poured into a doctor blade set to a predetermined height, and tape casting is performed by moving a PET substrate film at a speed of 1.0 m / min to 3.0 m / min to obtain a green sheet with a thickness of several tens of micrometers. The green sheet is sintered at a temperature of 1000 ℃ to 1350 ℃ through lamination, pressing, and cutting processes to obtain a sintered body. The sintered body can be placed in a mold and pressure applied to prepare a solid electrolyte molded body with a thickness of several hundred micrometers. Next, before applying and drying the composition for forming an intermediate layer on one side of the solid electrolyte, the one side of the solid electrolyte is surface-treated. Specifically, a solid electrolyte molded body is surface-treated to provide a solid electrolyte layer containing pores on the surface. The surface treatment may include, for example, chemical treatment, electrolytic polishing, wet polishing, argon plasma etching, oxygen plasma cleaning, annealing, or exposure to a high vacuum.

[0160] According to an exemplary embodiment, the surface treatment may be acid-treated one or more times. For acid treatment, hydrochloric acid, phosphoric acid, sulfuric acid, nitric acid, hydrofluoric acid, or a mixture thereof may be used. For example, acid treatment may be performed for 10 seconds to 20 minutes at a concentration of 0.1 M to 10 M. For example, acid treatment may be performed for 1 minute to 10 minutes with hydrochloric acid at a concentration of 0.1 M to 2 M at a temperature of 25 °C to 50 °C under an air atmosphere. Additionally, it may be performed for 10 seconds to 30 seconds with phosphoric acid at a concentration of 0.1 M to 1 M at a temperature of 25 °C to 50 °C under an air atmosphere. After acid treatment, the surface may be washed with alcohol and dried in a drying room to obtain a solid electrolyte layer containing pores on the surface.

[0161] Next, a composition for forming an intermediate layer is applied to one surface of the surface-treated solid electrolyte to cover 30% to 99.9% of the total surface area and dried to produce a solid electrolyte layer with an intermediate layer formed thereon. That is, the horizontal length of the intermediate layer may be shorter than the horizontal lengths of the cathode layer and the solid electrolyte layer. Non-limiting examples of the application method include doctor blade, bar coating, screen printing, spray coating, etc. Drying may be performed at room temperature for about 10 minutes to 1 hour.

[0162] The thickness of the intermediate layer may be, for example, 1 μm to 30 μm. For example, the thickness of the intermediate layer may be 1 μm to 28 μm, 1 μm to 26 μm, 1 μm to 24 μm, 1 μm to 22 μm, 1 μm to 20 μm, 1 μm to 18 μm, 1 μm to 16 μm, 1 μm to 14 μm, 1 μm to 12 μm, or 1 μm to 10 μm. The intermediate layer can prevent a decrease in energy density within the above thickness range.

[0163] Next, one or more electrolytes selected from liquid electrolytes, gel electrolytes, and polymer electrolytes are brought into contact with the surface of the solid electrolyte layer where the intermediate layer is not formed. Examples of contact include all methods such as dropping, coating, or impregnation.

[0164] Pre-lithiation may naturally occur in the edge portion between the cathode layer and the solid electrolyte layer, in the region where the intermediate layer is not located other than the edge portion, or in all of these regions.

[0165] Under conditions where direct electrical contact is realized between the negative electrode current collector and the lithium metal layer or lithium alloy layer, that is, during the charging and discharging of a lithium metal battery, a lithium plating layer may be formed on part or all of the interface between the intermediate layer and the solid electrolyte layer due to the potential difference between the lithium metal layer or lithium alloy layer and the intermediate layer, depending on the reduction potential. In other words, natural pre-lithiation occurs in the lithium metal battery.

[0166] Next, a cathode layer is disposed on one side of the solid electrolyte layer in which the intermediate layer is formed. The cathode layer includes the aforementioned cathode current collector and a lithium metal or lithium alloy layer.

[0167] Next, a lithium metal battery is manufactured by placing an anode layer on the other side of a solid electrolyte layer on which a cathode layer is placed. The anode layer includes an anode current collector and an anode active material layer. The anode active material layer includes the aforementioned anode active material and an anode electrolyte. The anode electrolyte may include an ionic liquid compound and a lithium salt. The anode electrolyte may be impregnated into the surface pores of the solid electrolyte layer in contact with the anode active material layer and into the interior of the anode layer.

[0168] It is manufactured by placing a naturally pre-lithiated cathode / intermediate / solid electrolyte layer structure and a positive electrode layer inside an aluminum pouch under vacuum and sealing it. At this time, parts of the positive and negative current collectors are protruded out of the aluminum pouch to serve as the positive and negative terminals, respectively, so as not to break the vacuum of the battery.

[0170] A lithium metal battery module containing a lithium metal battery as a unit cell

[0171] A lithium metal battery module comprising a lithium metal battery as a unit cell according to another embodiment comprises: a negative electrode layer comprising lithium metal or a lithium alloy; a solid electrolyte layer disposed on the negative electrode layer; and a positive electrode layer disposed on the solid electrolyte layer; and further comprises a region comprising an intermediate layer and a region not comprising an intermediate layer between the negative electrode layer and the solid electrolyte layer, wherein the region comprising the intermediate layer comprises an intermediate layer comprising a carbon material, and at least a portion of the region not comprising the intermediate layer may comprise one or more electrolytes selected from a liquid electrolyte, a gel electrolyte, and a polymer electrolyte.

[0172] A lithium metal battery module according to an exemplary embodiment comprises a battery stack in which a plurality of lithium metal battery unit cells are stacked; and a support member disposed on one or both sides of the battery stack. The battery stack may be stacked in the thickness direction of the lithium metal battery. The pressure applied by the support member to the battery stack may be 1 MPa or less. Alternatively, the support member may not apply pressure to the battery stack. The support member may be a plate, case, frame, etc., for fixing a plurality of lithium metal battery unit cells, but is not limited thereto, and any support member used in the art may be used.

[0173] Optionally, an elastic material may be further included between the battery stack and the support member. Optionally, an elastic material may be further included between a plurality of lithium metal battery unit cells.

[0174] For example, the elastic material may include urethane-based polymers, acrylate-based polymers, silicone-based polymers, fluorine-based polymers, copolymers thereof, or combinations thereof.

[0175] For example, the elastic material may include an elastic sheet.

[0176] For example, the compressive strain of the elastic sheet may be about 30% to 70% or 35% to 60%. An elastic sheet satisfying a compressive strain within the above range can sufficiently perform the role of relieving stress, reducing internal pressure changes, and absorbing shock between a lithium metal battery module or a plurality of lithium metal battery unit cells.

[0177] For example, the thickness of the elastic sheet may be 50 μm to 400 μm. For example, the thickness of the elastic sheet may be 100 μm to 300 μm. An elastic sheet having the above thickness can relieve stress and withstand internal pressure between a lithium metal battery module or a plurality of lithium metal battery unit cells.

[0178] A battery pack according to another embodiment may include a lithium metal battery module comprising the above-described lithium metal battery as a unit cell. The battery pack may be used in electric vehicles, hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), etc.

[0180] Examples and comparative examples of the present invention are described below. However, the following examples are merely one example of the present invention, and the present invention is not limited to the following examples.

[0182] [Example]

[0184] Example 1: Preparation of a lithium metal battery

[0185] (Composition for forming an intermediate layer)

[0186] Carbon black (CB35, Asahi Co.) powder was added to a mixture of water and a water-soluble binder, polyvinyl alcohol-grafted polyacrylic acid (PVA-g-10PAA), and stirred with a mixer (Thinky Corporation, AR-100) to prepare a composition for forming an intermediate layer. Polyvinyl alcohol-grafted polyacrylic acid (PVA-g-10PAA) was synthesized by graft polymerization of an acrylic acid monomer onto a polyvinyl alcohol backbone according to the method disclosed in reference J. He, L. Zhang, Journal of Alloys and Compounds 763 (2018) 228-240.

[0187] (Solid electrolyte layer with an intermediate layer)

[0188] Li with a thickness of 500 µm and a diameter of 14 mm 6.5 La3Zr 1.5 Ta 0.5 O 12 (LLZTO, Toshima Co.) A solid electrolyte pellet was prepared. The LLZTO solid electrolyte was subjected to a first acid treatment with 1.5 M hydrochloric acid at 40°C for 7 minutes, and then washed with ethanol. After that, the LLZTO solid electrolyte treated with the first acid was subjected to a second acid treatment with 1.0 M phosphoric acid at 40°C for 30 seconds, and then washed with ethanol to produce a solid electrolyte layer with pores formed on its surface.

[0189] A solid electrolyte layer with an intermediate layer approximately 7 μm thick was prepared by applying a composition for forming an intermediate layer to one side of a solid electrolyte layer having pores formed on its surface and drying it at room temperature for 20 minutes. The composition of the intermediate layer was 95 wt% carbon black and 5 wt% polyvinyl alcohol-grafted polyacrylic acid, based on the total weight of the intermediate layer. The area of ​​the intermediate layer applied to one side of the solid electrolyte layer was 0.636 cm² 2 , that is, it was about 41% of the total surface area of ​​the solid electrolyte layer.

[0190] (Solid electrolyte layer with electrolyte located at the edge)

[0191] A solid electrolyte layer with a liquid electrolyte located at the edge was prepared by gently wetting the edge portion of the solid electrolyte layer where no intermediate layer was formed with a small amount of liquid electrolyte. The composition of the liquid electrolyte was N-methyl-N-propyl-pyrrolidinium(fluorosulfonyl)imide (Pyrr1,3-FSI, 99.9%, water content <20 ppm, Kanto Chemical Co. Inc.) and 2.0 M lithium bis(fluorosulfonyl)imide (LiFSI, 99.9%, water content <10 ppm).

[0192] (Cathode layer)

[0193] 1.54 cm on the surface of the solid electrolyte layer with an intermediate layer formed 2 A 20 μm thick lithium metal was placed on a 10 μm thick copper foil (Honjo Metal Co., Ltd.) having an area and housed in a negative electrode case. At this time, the area of ​​the intermediate layer was approximately 41% based on the total surface area of ​​the negative electrode layer.

[0194] (Bipolar layer)

[0195] LiCoO2 (LCO, Samsung SDI) was prepared as the cathode active material. Carbon black (Super P) was used as the conductive agent. ® Polyvinylidene fluoride (Solef Li, Imerys Co.) was prepared as a binder. ® A material (5130, Solvay Co.) was prepared. The binder was used in the form of a solution dissolved in NMP at a ratio of 5 wt%. Subsequently, a composition for forming an anode active material layer was prepared by mixing these materials in a weight ratio of anode active material:conductive material:binder = 97.6:1.2:1.2. The composition for forming the anode active material layer was applied to a current collector of a 9 μm thick aluminum foil (Nippon Foil Mfg. Co., LTD) using an applicator at a loading capacity of 4.22 g / cc and a thickness of 46 μm, dried at 120°C for 12 hours, and then compressed to produce an anode active material layer.

[0196] The cathode active material layer was impregnated with a small amount of catholyte. The catholyte composition was prepared by mixing 2.0 M lithium bis(fluorosulfonyl)imide (LiFSI, 99.9%, moisture content <10 ppm) with the ionic liquid 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EMIM-FSI, 99.9%, moisture content <20 ppm, Kanto Chemical Co. Inc.).

[0197] (Lithium metal battery)

[0198] The manufactured cathode layer / intermediate layer / solid electrolyte layer / anode layer were assembled according to the standard CR2032 type coin cell configuration. After compression, the coin cell was preheated at 60°C for 20 hours.

[0200] Example 2: Preparation of a lithium metal battery

[0201] 0.95 cm on the surface of the solid electrolyte layer with an intermediate layer formed 2 A lithium metal battery was manufactured in the same manner as in Example 1, except that a 20 μm thick lithium metal was placed on a 10 μm thick copper foil (Honjo Metal Co., Ltd.) having an area and housed within a negative electrode case to manufacture the negative electrode layer. At this time, the area of ​​the intermediate layer was approximately 67% based on the total surface area of ​​the negative electrode layer.

[0203] Comparative Example 1: Manufacture of a lithium metal battery

[0204] A lithium metal battery was manufactured in the same manner as in Example 1, except that the liquid electrolyte was not applied to the edge portion of the solid electrolyte layer where an intermediate layer was not formed, thereby producing a solid electrolyte layer that does not contain electrolyte at the edge portion.

[0206] Evaluation Example 1: Electrochemical Impedance (EIS) Experiment

[0207] Electrochemical impedance experiments were performed on the lithium metal batteries prepared in Example 1, Example 2, and Comparative Example 1 to determine the charge transfer resistance (R ct ) was measured. The results are shown in Table 1.

[0208] In the electrochemical impedance experiment, the impedance of the lithium metal battery was measured using the 2-probe method with an impedance analyzer (Solartron 1400A / 1455A impedance analyzer), and the Nyquist plot is shown in Fig. 2. From this, the electrolyte resistance (Rs, left end) and the SEI resistance (R) formed on the electrode surface were determined. SEI , semicircle), and charge transfer resistance (R CT , right end) was obtained. The frequency range was 0.1 Hz to 1 MHz, and the amplitude voltage was 10 mV. It was measured at 25 ℃ in an air atmosphere.

[0209] division Charge transfer resistance (R ct , Ω) Example 1 130 Example 2 160 Comparative Example 1 587

[0210] Referring to Table 1 and Figure 2, the charge transfer resistance of the lithium metal batteries of Examples 1 and 2, which contain an electrolyte at the edge between the negative electrode layer and the solid electrolyte layer, was reduced compared to the lithium metal battery of Comparative Example 1, which does not contain an electrolyte at the edge between the negative electrode layer and the solid electrolyte layer. Therefore, it was confirmed that the charge transfer resistance of the solid electrolyte layer and the negative electrode is reduced by employing a solid electrolyte layer containing an electrolyte at the edge between the negative electrode layer and the solid electrolyte layer in the lithium metal batteries of Examples 1 and 2.

[0212] Evaluation Example 2: Charge / Discharge Experiment

[0213] (1) Open circuit voltage (OCV)

[0214] Before the charge-discharge experiment, the open-circuit voltage (OCV) was measured for the lithium metal batteries prepared in Example 1, Example 2, and Comparative Example 1. The results are shown in Table 2.

[0215] division OCV(V) Example 1 3.372 Example 2 3.344 Comparative Example 1 3.398

[0216] Referring to Table 2, the open circuit voltage (OCV) of the lithium metal batteries prepared in Examples 1 and 2 was lower than that of the lithium metal battery prepared in Comparative Example 1. It was confirmed that the lithium metal batteries prepared in Examples 1 and 2 can ensure the stability of lithium ion insertion and extraction.

[0218] Evaluation Example 3: Charge / Discharge Experiment

[0219] (1) Limiting current density (CCD)

[0220] The current density characteristics of the lithium metal batteries prepared in Example 1, Example 2, and Comparative Example 1 were evaluated by the following charge-discharge experiments, and the results are shown in Table 3, Fig. 3a, Fig. 3b, and Fig. 3c. The charge-discharge experiments were performed by placing the lithium metal batteries in a constant temperature bath at 25°C.

[0221] Charge-discharge cycles were performed from the first to the sixth cycle while increasing the current density. The current density in the cycle immediately preceding the cycle in which a short circuit occurs was considered as the limiting current density (CCD).

[0222] The first cycle is 0.3 mA / cm² until the battery voltage reaches 4.5 V. 2 It was charged with a constant current of 0.3 mA / cm² until the battery voltage reached 2.75 V. 2 Discharge was performed with a constant current.

[0223] The second to fourth cycles are 0.5 mA / cm² until the battery voltage reaches 4.5 V. 2 It was charged with a constant current of 0.5 mA / cm² until the battery voltage reached 2.75 V. 2 Discharge was performed with a constant current.

[0224] Cycles 5 through 7 are 1.0 mA / cm² until the battery voltage reaches 4.5 V. 2 It was charged with a constant current of 1.0 mA / cm² until the battery voltage reached 2.75 V. 2 Discharge was performed with a constant current.

[0225] Cycles 8 through 10 are 1.6 mA / cm² until the battery voltage reaches 4.5 V. 2 It was charged with a constant current of 1.6 mA / cm² until the battery voltage reached 2.75 V. 2 Discharge was performed with a constant current.

[0226] Cycles 11 through 13 are 2.0 mA / cm² until the battery voltage reaches 4.5 V. 2 It was charged with a constant current of 2.0 mA / cm² until the battery voltage reached 2.75 V. 2 Discharge was performed with a constant current.

[0227] Cycles 14 through 16 are 2.5 mA / cm² until the battery voltage reaches 4.5 V. 2 It was charged with a constant current of 2.5 mA / cm² until the battery voltage reached 2.75 V. 2 Discharge was performed with a constant current.

[0228] In all charge / discharge cycles, a pause of 1 minute was taken after each charge / discharge cycle.

[0229] Of these, 0.32 C-rate (1.0 mA / cm²) 2 The results of the capacity per area at current density are shown in Table 3.

[0230] division CCD(mA / cm 2 ) Cycle immediately before short circuit occurs Capacity per unit area (mAh / cm²) 2 )@ 0.32C, 25℃ Example 1 2.0 11 3.18 Example 2 1.0 6 3.05 Comparative Example 1 < 0.3 - -

[0231] Referring to Table 3, FIGS. 3a, 3b, and 3c, the lithium metal batteries of Example 1 and Example 2, which contain an electrolyte at the edge between the cathode layer and the solid electrolyte layer, have a high limiting current density (CCD) and a capacity per area of ​​3.05 mAh / cm². 2 It was higher than expected.

[0232] In comparison, the lithium metal battery of Comparative Example 1, which does not contain an electrolyte at the edge between the negative electrode layer and the solid electrolyte layer, experienced a short circuit. Explanation of the symbols

[0234] 1a,1'a: negative electrode current collector, 1b,1'b: lithium metal layer or lithium alloy layer, 1, 1': cathode layer, 2, 2': intermediate layer, 3, 3': solid electrolyte layer, 4: Liquid electrolyte or gel electrolyte at the interface edge, 4': Liquid electrolyte or polymer electrolyte at the interface edge, 10, 10': Cathode layer / intermediate layer / solid electrolyte layer structure

Claims

Claim 1 A lithium metal battery comprising: a negative electrode layer comprising lithium metal or a lithium alloy; a solid electrolyte layer disposed on the negative electrode layer; and a positive electrode layer disposed on the solid electrolyte layer; further comprising a region comprising an intermediate layer and a region not comprising an intermediate layer between the negative electrode layer and the solid electrolyte layer, wherein the region comprising the intermediate layer comprises an intermediate layer comprising a carbon material, and at least a portion of the region not comprising an intermediate layer comprises one or more electrolytes selected from a liquid electrolyte, a gel electrolyte, and a polymer electrolyte. Claim 2 A lithium metal battery according to claim 1, wherein the region not including the intermediate layer is an edge region between the negative electrode layer and the solid electrolyte layer, a region other than the edge region where the intermediate layer is not located, or a region of all of these. Claim 3 A lithium metal battery according to claim 1, wherein the area of ​​the intermediate layer is smaller than the area of ​​the negative electrode layer. Claim 4 A lithium metal battery according to claim 1, wherein the area of ​​the intermediate layer is 30% to 80% based on 100% of the total surface area of ​​the solid electrolyte layer. Claim 5 A lithium metal battery according to claim 1, wherein the thickness of the intermediate layer is 1 μm to 30 μm. Claim 6 A lithium metal battery according to claim 1, comprising lithium cations in a region not including the intermediate layer. Claim 7 A lithium metal battery according to claim 1, wherein the lithium metal battery comprises a lithium-containing layer in part or all of the interface between the intermediate layer and the solid electrolyte layer during charging and discharging. Claim 8 A lithium metal battery according to claim 1, wherein the intermediate layer comprises one or more carbon-based materials among carbon materials and carbon composites and a binder. Claim 9 A lithium metal battery according to claim 1, wherein the surface of the solid electrolyte layer includes pores, and the carbon material of the intermediate layer is filled in part or all of the pores on the surface of the solid electrolyte layer. Claim 10 In claim 1, the liquid electrolyte and gel electrolyte comprise an ionic liquid compound and a lithium salt, wherein the ionic liquid compound comprises i) one or more cations selected from ammonium-based, pyrrolidinium-based, pyridinium-based, pyrimidinium-based, imidazolium-based, piperidinium-based, pyrazolium-based, oxazolium-based, pyridazinium-based, phosphonium-based, sulfonium-based, triazole-based, and mixtures thereof, and ii) BF4-, PF6-, AsF6-, SbF6-, AlCl4-, HSO4-, ClO4-, CH3SO3-, CF3CO2-, (CF3SO2)2N-, Cl-, Br-, I-, BF4-, SO4 - , PF6-, ClO4-, CF3SO3-, CF3CO2-, (C2F5SO2)2N-, (C2F5SO2)(CF3SO2)N-, NO3 - , Al2Cl7 - , AsF6 - , SbF6 - , CF3COO - , CH3COO - , CF3SO3 - , (CF3SO2)3C - , (CF3CF2SO2)2N - , (CF3)2PF4 - , (CF3)3PF3 - , (CF3)4PF2 - , (CF3)5PF - , (CF3)6P - , SF5CF2SO3 - , SF5CHFCF2SO3 - , CF3CF2(CF3)2CO - , (CF3SO2)2CH - , (SF5)3C - , (O(CF3)2C2(CF3)2O)2PO - A lithium metal battery selected from ionic liquid compounds comprising one or more anions selected from and (CF3SO2)2N-. Claim 11 A lithium metal battery according to claim 1, wherein the polymer electrolyte comprises a polymer or copolymer comprising an ion-conducting repeating unit and a lithium salt, and the ion-conducting repeating unit comprises an ether-based monomer, an acrylic-based monomer, a methacrylic-based monomer, a siloxane-based monomer, or a combination thereof. Claim 12 A lithium metal battery according to claim 10 or 11, wherein the lithium salt has a concentration of 0.1 M to 5 M and comprises one or more selected from LiPF6, LiBF4, LiCF3SO3, Li(CF3SO2)2N, Li(CF3SO2)3C, LiC2F5SO3, Li(FSO2)2N, LiC4F9SO3, LiN(SO2CF2CF3)2, LiN(CN)2, and compounds represented by chemical formulas 11 to 14: [Chemical Formula 11] [Chemical Formula 12] [Chemical Formula 13] [Chemical Formula 14] , , , . Claim 13 In claim 1, the solid electrolyte layer is an oxide-based solid electrolyte, a polymer solid electrolyte, a polymer and inorganic hybrid electrolyte, or an organic and inorganic hybrid polymer electrolyte, or a combination thereof, and the oxide-based solid electrolyte is a Garnet-based ceramic Li 3+x La3M2O 12 (M=Te, Nb, or Zr) (x is an integer from 1 to 10), Li 1+x+y Al x Ti 2-x Si y P 3-y O 12 (0 <x<2, 0≤y<3), 리튬포스페이트(Li3PO4), 리튬티타늄포스페이트(Li x Ti y (PO4)3, 0 <x<2, 0<y<3), 리튬알루미늄티타늄포스페이트 (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), 리튬게르마늄티오포스페이트(Li x Ge y P z S w , 0 <x<4, 0<y<1, 0<z<1, 0<w<5), 리튬나이트라이드계열 글래스(Li x N y , 0 <x<4, 0<y<2), SiS2(Li x Si y S z , 0 <x<3,0<y<2, 0<z<4), P2S5계열 글래스(Li x P y S z , 0<x<3, 0<y<3, 0<z<7), Li2O, LiF, LiOH, Li2CO3, LiAlO2, Li2O-Al2O3-SiO2-P2O5-TiO2-GeO2계 세라믹스, 및 LiBSiO 중에서 선택된 하나 이상 또는 이들의 조합물인 것인, 리튬금속전지. Claim 14 A lithium metal battery according to claim 1, wherein the anode layer comprises an anode active material and an anode electrolyte, and the anode electrolyte comprises an ionic liquid compound and a lithium salt, and has a viscosity of 50 cps to 500 cps. Claim 15 In claim 1, the charge transfer resistance (R) by electrochemical impedance (EIS) analysis at 25 ℃ ct A lithium metal battery having a resistance of 240 Ω to 200 Ω. Claim 16 A method for manufacturing a lithium metal battery comprising: a step of preparing a composition for forming an intermediate layer by mixing one or more carbon-based materials and a binder among carbon materials and carbon composites; a step of preparing a solid electrolyte layer with an intermediate layer formed by applying and drying the composition for forming an intermediate layer to one surface of a solid electrolyte at a rate of 30% to 99.9% based on the total surface area; a step of contacting one or more electrolytes among a liquid electrolyte, a gel electrolyte, and a polymer electrolyte to the surface of the solid electrolyte layer where the intermediate layer is not formed; a step of placing a negative electrode layer on one surface of the solid electrolyte layer where the one surface of the solid electrolyte layer with the intermediate layer formed and one or more electrolytes among the liquid electrolyte, gel electrolyte, and polymer electrolyte are in contact; and a step of manufacturing a lithium metal battery by placing a positive electrode layer on the other surface of the solid electrolyte layer where the negative electrode layer is placed. Claim 17 A method for manufacturing a lithium metal battery according to claim 16, further comprising the step of surface treating one surface of the solid electrolyte before applying and drying the composition for forming an intermediate layer on one surface of the solid electrolyte, wherein the surface treatment includes chemical treatment, electrolytic polishing, wet polishing, argon plasma etching, oxygen plasma cleaning, annealing, or exposure to a high vacuum. Claim 18 A method for manufacturing a lithium metal battery according to claim 16, wherein pre-lithiation naturally occurs in the edge portion between the cathode layer and the solid electrolyte layer, in the region where an intermediate layer is not located in addition to the edge portion, or in all of these regions. Claim 19 A method for manufacturing a lithium metal battery according to claim 16, wherein a lithium plating layer is formed according to a reduction potential on part or all of the interface between the intermediate layer and the solid electrolyte layer during charging and discharging of the lithium metal battery. Claim 20 A lithium metal battery module comprising a lithium metal battery as a unit cell, the lithium metal battery comprising: a negative electrode layer comprising lithium metal or a lithium alloy; a solid electrolyte layer disposed on the negative electrode layer; and an anode layer disposed on the solid electrolyte layer; and further comprising a region comprising an intermediate layer and a region not comprising an intermediate layer between the negative electrode layer and the solid electrolyte layer, wherein the region comprising the intermediate layer comprises an intermediate layer comprising a carbon material, and at least a portion of the region not comprising an intermediate layer comprises one or more electrolytes selected from a liquid electrolyte, a gel electrolyte, and a polymer electrolyte.

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