Negative electrode for all-solid-state battery, all-solid-state battery including negative electrode, and method for manufacturing all-solid-state battery

Abstract

A negative electrode, an all-solid-state battery including the negative electrode, and a method for manufacturing the all-solid-state battery are provided. The negative electrode includes a negative electrode current collector, a coating layer including carbon and a first metal on the negative electrode current collector, and a functional layer between the negative electrode current collector and the coating layer. The functional layer includes a second metal. Each of the first and second metals includes at least one lithium-philic element selected from the group consisting of silver (Ag), gold (Au), magnesium (Mg), indium (In), titanium (Ti), gallium (Ga), platinum (Pt), palladium (Pd), silicon (Si), aluminum (Al), bismuth (Bi), tin (Sn), and / or zinc (Zn).

Description

[0001] This application claims priority and benefit to Korean Patent Application No. 10-2024-0122545, filed on September 9, 2024, with the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference. Technical Field

[0002] This disclosure relates to a negative electrode for an all-solid-state battery and an all-solid-state battery including the negative electrode. Background Technology

[0003] The development of high-energy-density and safe batteries has been driven by industry demand. Recently, all-solid-state batteries using solid electrolytes instead of liquid electrolytes have been proposed. All-solid-state batteries are densified by stacking positive electrodes, solid electrolytes, and negative electrodes. They use solid electrolytes instead of the liquid electrolytes used in comparable rechargeable batteries. Because all-solid-state batteries do not use the flammable organic dispersion medium (of liquid electrolytes), the possibility of fire and / or explosion is significantly reduced, even in the event of a short circuit. Therefore, such all-solid-state batteries can exhibit high stability. Summary of the Invention

[0004] One or more aspects of this disclosure relate to a negative electrode for an all-solid-state battery that promotes (e.g., enhances or improves) substantially uniform growth of a lithium metal layer during charging and discharging, and enhances or improves ionic conductivity.

[0005] One or more aspects of this disclosure relate to all-solid-state batteries having enhanced or improved electrochemical properties.

[0006] Additional aspects will be set forth in part in the description which follows, and in part will be apparent from the description, or may be learned by practice of the disclosed embodiments.

[0007] In one or more embodiments of this disclosure, the negative electrode includes: a negative electrode current collector; a coating layer on the negative electrode current collector and comprising carbon and a first metal; and a functional layer between the negative electrode current collector and the coating layer. The functional layer includes a second metal. Each of the first metal and the second metal includes at least one lithium-loving element selected from silver (Ag), gold (Au), magnesium (Mg), indium (In), titanium (Ti), gallium (Ga), platinum (Pt), palladium (Pd), silicon (Si), aluminum (Al), bismuth (Bi), tin (Sn), and / or zinc (Zn). The battery is an all-solid-state battery.

[0008] In one or more embodiments of this disclosure, the all-solid-state battery includes: a positive electrode; a negative electrode opposite to the positive electrode; and a solid electrolyte layer between the positive and negative electrodes. The negative electrode includes: a negative electrode current collector; a coating layer on the negative electrode current collector; and a functional layer between the negative electrode current collector and the coating layer. The coating layer includes carbon and a first metal. The functional layer includes a second metal. Each of the first and second metals is a lithium-philic metal. The thickness of the coating layer is greater than the thickness of the functional layer. The thickness of the functional layer is in the range of about 30 nm to about 4 μm.

[0009] In one or more embodiments of this disclosure, a method includes: forming (e.g., applying) a functional layer on a first surface of a negative electrode current collector; and forming (e.g., applying) a coating layer on the functional layer. The coating layer includes carbon and a first metal. The formation of the functional layer includes performing a sputtering process to form (e.g., deposit) a second metal on the first surface of the negative electrode current collector. Each of the first metal and the second metal includes at least one lithium-philic element selected from silver (Ag), gold (Au), magnesium (Mg), indium (In), titanium (Ti), gallium (Ga), platinum (Pt), palladium (Pd), silicon (Si), aluminum (Al), bismuth (Bi), tin (Sn), and / or zinc (Zn). The method is a method for manufacturing an all-solid-state battery. Attached Figure Description

[0010] Figure 1 A plan view illustrating an all-solid-state battery according to one or more embodiments of the present disclosure is shown.

[0011] Figure 2 A cross-sectional view of an all-solid-state battery according to one or more embodiments of the present disclosure is shown.

[0012] Figure 3 A cross-sectional view of an all-solid-state battery according to one or more embodiments of the present disclosure is shown.

[0013] Figure 4 A cross-sectional view is shown illustrating a negative electrode for an all-solid-state battery according to one or more embodiments of the present disclosure.

[0014] Figure 5 It shows Figure 4 A magnified view of part M.

[0015] Figure 6 It shows Figure 4 A magnified view of part N.

[0016] Figure 7 A cross-sectional view is shown illustrating a negative electrode for an all-solid-state battery according to one or more embodiments of the present disclosure.

[0017] Figure 8 SEM images of the negative electrode for an all-solid-state battery according to one or more embodiments of the present disclosure are shown.

[0018] Figure 9 SEM images of the functional layer of the negative electrode according to one or more embodiments of the present disclosure are shown.

[0019] Figure 10 The graphs shown illustrate the cycle characteristics of all-solid-state batteries according to embodiments and comparative examples.

[0020] Figure 11A SEM images of the negative electrode for an all-solid-state battery according to Example 1 are shown.

[0021] Figure 11B SEM images of the negative electrode for an all-solid-state battery, taken according to other examples, are shown.

[0022] Figure 12 The XRD analysis results of the negative electrode for an all-solid-state battery according to Example 1 are shown. Detailed Implementation

[0023] In the following description, embodiments of the present disclosure will be clearly and in more detail to the extent that those skilled in the art can readily implement the present disclosure. To fully understand the structure and effects of the present disclosure, one or more embodiments will be described with reference to the accompanying drawings. However, it should be noted that the present disclosure is not limited to the following exemplary embodiments and may be implemented in one or more suitable forms. Rather, exemplary embodiments are provided merely to disclose the present disclosure and to enable those skilled in the art to fully understand its scope.

[0024] In this specification, it will be understood that if (for example, when) an element is referred to as being on another element, then the element may be directly on said other element, or an intermediary element may exist between them. Conversely, if (for example, when) an element is referred to as being "directly on" another element, then no intermediary element exists. In the accompanying drawings, the thickness of some components is exaggerated for the purpose of effectively explaining the technical content. The same reference numerals always denote the same elements, and their repeated description may not be provided in the specification.

[0025] Some embodiments detailed in this specification will be discussed with reference to sectional views and / or plan views, which serve as ideal example views of this disclosure. In the drawings, the thickness of layers and regions is exaggerated for the purpose of effectively explaining the technical content. Therefore, the regions exemplarily shown in the drawings have general characteristics, and the shapes of the regions exemplarily shown in the figures are used to exemplarily disclose specific shapes but do not limit the scope of this disclosure. It will be understood that although the terms “first,” “second,” “third,” etc., may be used herein to describe one or more suitable elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. The one or more embodiments explained and illustrated herein include complementary embodiments thereof.

[0026] Unless otherwise specified in this specification, singular expressions (e.g., "a," "an," and / or "the") may include plural expressions containing "at least one," unless the context clearly indicates otherwise. Furthermore, unless otherwise specified, the phrase "A or B" may mean "A but not B," "B but not A," and "A and B." The terms "having / including / comprising" and / or variations thereof as used in this specification are intended to indicate the presence of aspects, quantities, steps (e.g., actions or tasks), elements, and / or (e.g., any suitable) combinations thereof, and do not exclude or exclude the presence or addition of one or more other features, quantities, steps (e.g., actions or tasks), elements, components, and / or (e.g., any suitable) combinations thereof. Furthermore, the terms “comprising,” “including,” “having,” or other similar terms include or support the terms “consisting of,” “substantially consisting of,” which indicate the presence of the stated features, integers, steps, operations, elements, and / or components, while other features, integers, steps, operations, elements, components, and / or groups thereof are absent or substantially absent.

[0027] In one or more embodiments, the term "layer" herein includes not only shapes that form across the entire surface when viewed from a plan view, but also shapes that form on a portion of the surface.

[0028] It will be understood that although the terms “first,” “second,” “third,” etc., may be used herein to describe one or more suitable elements, components, regions, layers, and / or portions, these elements, components, regions, layers, and / or portions should not be limited by these terms. These terms are used only to distinguish one element, component, region, layer, or portion from another. Therefore, without departing from the teachings set forth herein, a first element, first component, first region, first layer, or first portion described herein may be referred to as a second element, second component, second region, second layer, or second portion.

[0029] As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of…”, “one of…”, and “selected from…” modify the entire list of elements without modifying any individual element in the list if (e.g., when) they follow / before a list of elements. For example, the expressions “at least one of a to c”, “at least one of a, b, or c”, and “at least one of a, b, and / or c” can indicate only a, only b, only c, (e.g., simultaneously) both a and b, (e.g., simultaneously) both a and c, (e.g., simultaneously) both b and c, all of a, b, and c, or variations thereof.

[0030] Spatial relative terms such as “below,” “under,” “lower,” “above,” and “upper” can be used here to readily describe the relationship between one element or feature and another. It will be understood that, in addition to the orientations shown in the figures, the spatial relative terms are also intended to cover different orientations of the device during use or operation. For example, if (e.g., when) the device in the figures is flipped, an element described as “below” or “under” other elements or features will be oriented “above” said other elements or features. Thus, the example term “below” can (e.g., simultaneously) cover both above and below orientations. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatial relative terms used herein can be interpreted accordingly.

[0031] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. Unless otherwise defined, all terms used herein (including chemical, technical, and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It will also be understood that terms (such as those defined in common dictionaries) should be interpreted as having the same meaning as they have in the context of the relevant technology and this disclosure, and will not be interpreted in an idealized or overly formalized sense.

[0032] Example embodiments are described herein with reference to cross-sectional views as idealized embodiments. Thus, variations in the illustrated shapes due to, for example, manufacturing techniques and / or tolerances will be expected. Therefore, the embodiments described herein should not be construed as limited to the specific shapes of the areas shown herein, but rather include shape deviations due to, for example, manufacturing processes. For example, areas shown or described as flat may generally have rough and / or non-linear characteristics. Furthermore, the sharp corners shown may be rounded. Therefore, the areas shown in the figures are schematic in nature, and their shapes are not intended to show the precise shape of the areas, nor are they intended to limit the scope of the given claims.

[0033] The term “may” will be understood to refer to “one or more embodiments of this disclosure,” some of which include the described elements, and some of which exclude the described elements and / or include alternative elements. Similarly, alternative language such as “or” refers to “one or more embodiments of this disclosure,” each including the corresponding listed item.

[0034] In this context, "consisting essentially of" means that any additional components will not substantially affect the chemical, physical, optical, or electrical properties of the semiconductor film.

[0035] Furthermore, in this specification, the phrase "in a plane" or "plan view" indicates a view of the target portion from the top, and the phrase "in a cross-section" indicates a view of the cross-section formed by vertically cutting the target portion from the side.

[0036] In this specification, the term "combination thereof" may refer to mixtures, stacks, complexes, copolymers, alloys, blends and / or reaction products.

[0037] In this specification, phrases such as “A or B”, “at least one of A and B”, “at least one of A or B”, “A, B or C”, “at least one of A, B and C”, and “at least one of A, B or C” may each include any one of the items listed together with the corresponding phrase in the phrase or any possible combination thereof.

[0038] As used herein, the terms "particle size," "particle diameter," etc., refer to the average diameter of the particles if (e.g., when) the particles are spherical, and the average length of the major axis of the particles if (e.g., when) the particles are non-spherical. For example, particle size can be the average particle size. In some embodiments, particle size represents the average particle size (D) of particles that constitute approximately 50% by volume of the cumulative volume in a particle size distribution. 50 Average particle size (D) 50The particle size can be measured using a wide range of methods suitable to those skilled in the art, such as by a particle size analyzer, transmission electron microscopy (TEM) images, or scanning electron microscopy (SEM) images. In one or more embodiments, data analysis is performed using a dynamic light scattering measurement device to count the number of particles for each particle size range, from which the average particle size (D) can then be calculated. 50 The average particle size (D) value can be measured using laser scattering in one or more embodiments. 50 In laser scattering, target particles are dispersed in a dispersion solvent and introduced into a laser scattering particle measuring device (e.g., the MT 3000, commercially available from Microtrac). The particles are irradiated with 28 kHz ultrasound at a power of 60 W, and the average particle size (D) is calculated using a standard of 50% of the particle size distribution in the measuring device. 50 ).

[0039] Figure 1 A plan view illustrating an all-solid-state battery according to one or more embodiments of the present disclosure is shown. Figure 2 It shows along Figure 1 A sectional view taken by line A-A'.

[0040] Reference Figure 1 and Figure 2 The all-solid-state battery 10 according to this disclosure may include a positive electrode layer 100, a negative electrode layer 200 opposite to the positive electrode layer 100, and a solid electrolyte layer 300 disposed between the positive electrode layer 100 and the negative electrode layer 200. However, this disclosure is not limited thereto, and the all-solid-state battery 10 may further include additional functional layers, such as an adhesion enhancement layer, disposed between the positive electrode layer 100 and the solid electrolyte layer 300 and / or between the negative electrode layer 200 and the solid electrolyte layer 300.

[0041] The positive electrode layer 100 according to one or more embodiments of the present disclosure may include a positive electrode current collector 110 and a positive electrode active material layer 120 disposed on the positive electrode current collector 110. The positive electrode active material layer 120 may include a positive electrode active material, a solid electrolyte, a conductive material and / or a binder.

[0042] The positive electrode current collector 110 can provide a reference surface on which the positive electrode active material layer 120 is disposed. The positive electrode current collector 110 may include a plate or foil containing, for example, indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li) and / or alloys thereof.

[0043] and Figure 2As shown in the differences, in one or more embodiments of this disclosure, the positive electrode current collector 110 may not be provided. In one or more embodiments, in order to increase the adhesion between the positive electrode current collector 110 and the positive electrode active material layer 120, a carbon layer having a thickness of about 0.1 μm to about 4 μm (e.g., in the range of about 0.1 μm to about 4 μm) may be further disposed between the positive electrode current collector 110 and the positive electrode active material layer 120.

[0044] The positive electrode active material of the positive electrode active material layer 120 may include materials capable of reversibly inserting and deintercalating lithium ions. The positive electrode active material may include multiple particles. For example, the positive electrode active material may include lithium transition metal oxides (e.g., lithium cobalt oxide (LCO), lithium nickel oxide, lithium nickel cobalt oxide, lithium nickel cobalt aluminum oxide (NCA), lithium nickel cobalt manganese oxide (NCM), lithium manganese oxide, and / or lithium iron phosphate), nickel sulfide, copper sulfide, lithium sulfide, iron oxide, and / or vanadium oxide, but this disclosure is not limited thereto. The positive electrode active material may be used alone or in a mixture of two or more substances.

[0045] Lithium transition metal oxides can be one or more compounds represented by one or more of the following (selected from the following): Li a A 1-b B b D2 (where 0.90≤a≤1 and 0≤b≤0.5), Li a E 1-b B b O 2-c D c (Where, 0.90≤a≤1, 0≤b≤0.5 and 0≤c≤0.05), LiE 2-b B b O 4-c D c (where 0 ≤ b ≤ 0.5 and 0 ≤ c ≤ 0.05), Li a Ni 1-b-c Co b B c D α (Where, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05 and 0<α<2), Li a Ni 1-b-c Co b B c O 2-α F α (Where, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05 and 0<α<2), Li a Ni 1-b-c Mn b B c Dα (Where, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05 and 0<α≤2), Li a Ni 1-b-c Mn b B c O 2-α F α (Where, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05 and 0<α<2), Li a Ni b E c G d O2 (where 0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5 and 0.001≤d≤0.1), Li a Ni b Co c Mn d G e O2 (where 0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5 and 0.001≤e≤0.1), Li a NiG b O2 (where 0.9≤a≤1 and 0.001≤b≤0.1), Li a CoG b O2 (where 0.90≤a≤1 and 0.001≤b≤0.1), Li a MnG b O2 (where 0.90≤a≤1 and 0.001≤b≤0.1), Li a Mn2G b O4 (where 0.90≤a≤1 and 0.001≤b≤0.1), QO2, QS2, LiQS2, V2O5, LiV2O5, LiIO2, LiNiVO4, Li 3-f J2(PO4)3 (where 0≤f≤2), Li 3-fFe2(PO4)3 (where 0 ≤ f ≤ 2) and / or LiFePO4. In the above compounds, "A" can be Ni, Co, Mn, and / or a combination thereof (e.g., any suitable combination), "B" can be Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements, and / or a combination thereof (e.g., any suitable combination), "D" can be O, F, S, P, and / or a combination thereof (e.g., any suitable combination), "E" can be Co, Mn, and / or a combination thereof (e.g., any suitable combination), "F" can be F, S, P, and / or a combination thereof (e.g., any suitable combination), "G" can be Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, and / or a combination thereof (e.g., any suitable combination), "Q" can be Ti, Mo, Mn, and / or a combination thereof (e.g., any suitable combination), "I" can be Cr, V, Fe, Sc, Y, and / or a combination thereof (e.g., any suitable combination), and "J" can be V, Cr, Mn, Co, Ni, Cu, and / or a combination thereof (e.g., any suitable combination).

[0046] The positive electrode active material can include, for example, a lithium salt of a transition metal oxide having a layered rock salt-type (like) structure among the lithium transition metal oxides discussed above. The term "layered rock salt-type (like) structure" can refer to a structure in which oxygen atom layers and metal atom layers are alternately and regularly arranged in the <111> direction of a cubic rock salt-type (like) structure, where each atom layer forms a two-dimensional plane. The term "cubic rock salt-type (like) structure" can refer to a sodium chloride (NaCl)-type (like) structure, which is one (type) of crystal structure and, for example, has a face-centered cubic lattice (FCC) formed by cations and anions respectively, with each being shifted (e.g., spaced apart or separated) by 1 / 2 of the edge of the unit lattice. The lithium transition metal oxide having a layered rock salt-type (like) structure can be a ternary lithium transition metal oxide, such as LiNi x Co y Al z O2 (NCA) and / or LiNi x Co y Mn z O2 (NCM) (where 0 < x < 1, 0 < y < 1, 0 < z < 1, and x + y + z = 1). If (e.g., when) the positive electrode active material includes a ternary lithium transition metal oxide having a layered rock salt-type (like) structure, the all-solid-state battery 10 can have an increased energy density and improved thermal stability.

[0047] The compound included in the positive electrode active material may be coated with a coating layer. The positive electrode active material may be used as a mixture of the compound and the compound to which the coating layer is added. The coating layer added to the surface of the positive electrode active material may include, for example, oxides, hydroxides, hydroxyoxides, oxycarbonates and / or bicarbonates of the coating elements discussed. The compound constituting the coating layer may be amorphous and / or crystalline. The coating elements included in the coating layer may include Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr and / or mixtures thereof (e.g., any suitable). The coating layer may include, for example, Li₂O-ZrO₂ (LZO). The method for forming the coating layer may be selected from any method that does not adversely affect the physical properties of the positive electrode active material. The method for forming the coating layer may include, for example, spraying and / or dipping.

[0048] If (for example, when) the positive electrode active material includes nickel (Ni) as a ternary lithium transition metal oxide such as NCA and / or NCM, the capacity density of the all-solid-state battery 10 can be increased to reduce metal stripping from the positive electrode active material in the state of charge. Therefore, the all-solid-state battery 10 can improve its cycle characteristics in the state of charge. The term "cycle characteristics" can refer to a property indicating the degree of degradation of the all-solid-state battery 10 due to charging and discharging. For example, an all-solid-state battery 10 with high cycle characteristics may degrade less due to charging and discharging, while an all-solid-state battery 10 with low cycle characteristics may degrade more due to charging and discharging.

[0049] The positive electrode active material can have, for example, spherical or elliptical particle shapes. There are no restrictions on the particle size and amount of the positive electrode active material.

[0050] The solid electrolyte of the positive electrode active material layer 120 can have a particulate shape. The solid electrolyte can be dispersed between the positive electrode active materials. The solid electrolyte can include sulfide-based solid electrolytes with excellent or suitable lithium-ion conductivity. Sulfide-based solid electrolytes can include, for example, those from Li₂S-P₂S₅, Li₂S-P₂S₅-LiX (where X is a halogen element), Li₂S-P₂S₅-Li₂O, Li₂S-P₂S₅-Li₂O-LiI, Li₂S-SiS₂, Li₂S-SiS₂-LiI, Li₂S-SiS₂-LiBr, Li₂S-SiS₂-LiCl, Li₂S-SiS₂-B₂S₃-LiI, Li₂S-SiS₂-P₂S₅-LiI, Li₂S-B₂S₃, and Li₂S-P₂S₅-ZmS. n (Where m and n are both positive integers, and "Z" is one of Ge, Zn, and Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Lip MO q (Where p and q are both positive integers, and "M" is one of P, Si, Ge, B, Al, Ga, and In), Li 7-x PS 6-x Cl x (where 0≤x≤2), Li 7-x PS 6-x Br x (where 0 ≤ x ≤ 2) and / or Li 7-x PS 6-x I x At least one of the following (where 0 ≤ x ≤ 2).

[0051] Sulfide solid electrolytes can be sulfide-germanium ore type (or similar) compounds, which include, for example, compounds selected from Li 7-x PS 6-x Cl x (where 0≤x≤2), Li 7-x PS 6-x Br x (where 0 ≤ x ≤ 2) and / or Li 7-x PS 6-x I x (where 0 ≤ x ≤ 2) at least one of them. For example, sulfide solid electrolytes may be sulfide-germanium ore type (or similar) compounds including at least one selected from Li6PS5Cl, Li6PS5Br and / or Li6PS5I.

[0052] In one or more embodiments, the sulfide-based solid electrolyte may be including Li 7-a M a PS 6-c X c (where 0≤a≤2 and 0≤c≤2) sulfo-silver-germanium minerals (or similar) compounds. In the above chemical formula, X can be F, Br, Cl and / or (e.g., any suitable) combinations thereof. M can be scandium (Sc), yttrium (Y), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), arsenic (As), antimony (Sb), bismuth (Bi) and / or any suitable combination thereof.

[0053] Australite-type (or similar) solid electrolytes can have a density of approximately 1.5 g / cc to approximately 2.0 g / cc. Because australite-type (or similar) solid electrolytes have a density equal to or greater than approximately 1.5 g / cc, they can reduce the internal resistance of all-solid-state batteries and prevent or reduce short circuits and penetration of the solid electrolyte layer due to lithium dendrite formation. The solid electrolyte can have an elastic modulus, for example, from approximately 15 GPa to approximately 35 GPa.

[0054] The solid electrolyte in the positive electrode active material layer 120 may be in particulate form and have an average particle size smaller than the average particle size of the first and second solid electrolytes in the solid electrolyte layer 300 to be discussed. For example, the average particle size of the solid electrolyte (in particulate form) in the positive electrode active material layer 120 may be equal to or less than about 90%, about 80%, about 70%, about 60%, about 50%, about 40%, about 30%, or about 20% of the average particle size of the solid electrolytes included in the solid electrolyte layer 300. The average particle size may be the median particle size measured using a laser-type particle size distribution analyzer.

[0055] The positive electrode active material layer 120 may include a conductive material. The conductive material can be conductive without causing chemical changes in the all-solid-state battery 10, thereby increasing the conductivity of the positive electrode active material and the solid electrolyte. The conductive material may include carbon-based materials. The conductive material may include one or more of, for example, graphite, carbon black, acetylene black, carbon nanofibers, and / or carbon nanotubes.

[0056] The positive electrode active material layer 120 may also include an adhesive. The adhesive can bond the positive electrode active material, solid electrolyte, and / or conductive material within the positive electrode active material layer 120. The adhesive may include materials that improve the adhesion between the positive electrode active material layer 120 and the positive electrode current collector 110. The adhesive may include, for example, polyvinylidene fluoride, styrene-butadiene rubber (SBR), polytetrafluoroethylene, vinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, and / or polymethyl methacrylate.

[0057] Based on a total of 100 parts by weight of the positive electrode active material, solid electrolyte, conductive material, and binder (e.g., a total of 100 parts by weight of the positive electrode active material layer 120), the positive electrode active material may be included in the positive electrode active material layer 120 in an amount of about 85 parts by weight to about 92 parts by weight. Based on a total of 100 parts by weight of the positive electrode active material, solid electrolyte, conductive material, and binder (e.g., a total of 100 parts by weight of the positive electrode active material layer 120), the positive electrode binder may be included in the positive electrode active material layer 120 in an amount of about 0.5 parts by weight to about 1.5 parts by weight. For example, the positive electrode active material layer 120 is composed of the positive electrode active material, solid electrolyte, conductive material, and binder. Based on a total of 100 parts by weight of the positive electrode active material layer 120, the positive electrode active material accounts for about 85 to 92 parts by weight, while the binder accounts for about 0.5 to 1.5 parts by weight.

[0058] Based on 100 parts by weight of solid electrolyte, conductive material may be included in the positive electrode active material layer 120 in an amount from about 1 part by weight to about 50 parts by weight (e.g., the weight ratio of solid electrolyte to conductive material in the positive electrode active material layer 120 is from about 100:1 to about 2:1). If (e.g., when) conductive material is included in an amount less than about 1 part by weight relative to 100 parts by weight of solid electrolyte, the proportion of conductive material will decrease, thereby reducing the conductivity of the positive electrode active material layer 120. If (e.g., when) conductive material is included in an amount greater than about 50 parts by weight relative to 100 parts by weight of solid electrolyte, the proportion of conductive material will be excessively (or significantly) increased, resulting in incomplete formation of the coating layer covering the surface of the solid electrolyte. For example, the positive electrode active material layer 120 includes conductive material (e.g., an electronic conductor) in an amount ranging from about 1 part by weight to 50 parts by weight per 100 parts by weight of solid electrolyte. If the conductive material is less than 1 part by weight, the conductivity may decrease. If the conductive material exceeds 50 parts by weight, the coating layer on the surface of the solid electrolyte may not be fully formed.

[0059] In addition to the positive electrode active material, solid electrolyte, conductive material and binder, the positive electrode active material layer 120 may also include additives such as fillers, coating agents, dispersants and / or ionic conductive agents.

[0060] The negative electrode layer 200 may include a negative electrode current collector 210, a functional layer 230 on the negative electrode current collector 210, and a coating layer 220 on the functional layer 230.

[0061] The negative electrode current collector 210 can provide a reference surface on which the coating layer 220 is disposed. The negative electrode current collector 210 may include a material that does not react with lithium, for example, a material that does not form alloys and / or compounds with lithium. For example, the negative electrode current collector 210 may include at least one metal selected from copper (Cu), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), and / or nickel (Ni). The thickness of the negative electrode current collector 210 may be in the range of about 1 μm to about 20 μm, for example, about 5 μm to about 15 μm or about 7 μm to about 10 μm.

[0062] The negative electrode current collector 210 may be formed of one of the aforementioned metals (e.g., Cu, Ti, Fe, Co, and / or Ni), an alloy of two or more of the aforementioned metals (e.g., Cu, Ti, Fe, Co, and / or Ni), or a coating material comprising one of the aforementioned metals (e.g., Cu, Ti, Fe, Co, and / or Ni), or an alloy of two or more of the aforementioned metals (e.g., Cu, Ti, Fe, Co, and / or Ni). The negative electrode current collector 210 may have, for example, a plate shape or a foil shape. In one or more embodiments, the negative electrode current collector 210 may not be provided.

[0063] In one or more embodiments, a carbon layer may also be included to increase the adhesion between the coating layer 220 and the solid electrolyte layer 300.

[0064] A solid electrolyte layer 300 may be disposed between the positive electrode layer 100 and the negative electrode layer 200. The solid electrolyte layer 300 may include a sulfide-based solid electrolyte having excellent or suitable lithium-ion conductivity. The solid electrolyte included in the solid electrolyte layer 300 may contain the same or different material as the solid electrolyte included in the positive electrode active material layer 120.

[0065] The solid electrolyte layer 300 may include a first solid electrolyte layer 310 and a second solid electrolyte layer 320. The first solid electrolyte layer 310 may be adjacent to the positive electrode layer 100, and the second solid electrolyte layer 320 may be adjacent to the negative electrode layer 200.

[0066] Reference Figure 2The first solid electrolyte layer 310 may include a first solid electrolyte. The first solid electrolyte may have a spherical or elliptical particle shape. The first solid electrolyte may include a sulfide-based solid electrolyte. The first solid electrolyte may be in an amorphous, crystalline, or mixed state of amorphous and crystalline states. The solid electrolyte may include at least sulfur (S), phosphorus (P), and / or lithium (Li) among the constituent elements included in the above-mentioned sulfide-based solid electrolytes. For example, the solid electrolyte may be a material comprising Li₂S-P₂S₅. If (for example, when) Li₂S-P₂S₅ is used as the sulfide-based solid electrolyte material of the solid electrolyte, the molar ratio of Li₂S and P₂S₅ may be in the range of about 50:50 to about 90:10.

[0067] For example, the first solid electrolyte may include a pyrrhotgermanium-type (or similar) compound, which includes, for example, compounds selected from Li 7-x PS 6-x Cl x (where 0≤x≤2), Li 7-x PS 6-x Br x (where 0 ≤ x ≤ 2) and / or Li 7-x PS 6- x I x (where 0 ≤ x ≤ 2) at least one of the following. The first solid electrolyte may include a sulfide-germanium mineral (or similar) compound comprising at least one of Li6PS5Cl, Li6PS5Br and / or Li6PS5I.

[0068] In one or more embodiments, the first solid electrolyte may include Li 7-a M a PS 6-c X c A sulfide-germanium ore-type (or similar) compound. In the chemical formula above, X can be Cl, Br, and / or any suitable combination thereof. M can be Na, K, Fe, Mg, Ca, Ag, Cu, Zr, Zn, and / or any suitable combination thereof. Subscripts a and c can each be a real number between 0 and 2.

[0069] The sulfide-germanium ore-type (or similar) solid electrolyte can have a density in the range of about 1.5 g / cc to about 2.0 g / cc. Because the sulfide-germanium ore-type (or similar) solid electrolyte has a density equal to or greater than about 1.5 g / cc, it is possible to reduce the internal resistance of the all-solid-state battery and prevent or reduce short circuits and penetration of the solid electrolyte layer due to the formation of lithium dendrites. The first solid electrolyte can have a modulus, for example, from about 15 GPa to about 35 GPa.

[0070] The first solid electrolyte layer 310 may further include an adhesive. Adhesives included in the first solid electrolyte layer 310 may include, for example, styrene-butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, and / or polyethylene, but this disclosure is not limited thereto. The adhesive of the first solid electrolyte layer 310 may be the same as or different from the adhesive of the positive electrode active material layer 120 and / or the adhesive of the coating layer 220.

[0071] The second solid electrolyte layer 320 may include a second solid electrolyte. The second solid electrolyte may have a spherical or elliptical particle shape.

[0072] The second solid electrolyte may include a sulfide-based solid electrolyte. The description of the second solid electrolyte may be the same as or similar to that of the first solid electrolyte. In one or more embodiments, the second solid electrolyte may have a composition substantially the same as that of the first solid electrolyte. In one or more embodiments, the second solid electrolyte may have a composition similar to that of the first solid electrolyte.

[0073] The second solid electrolyte can be in direct contact with the coating layer 220. Therefore, the second solid electrolyte can suppress or reduce lithium dendrites formed between the coating layer 220 and the negative electrode current collector 210. The second solid electrolyte can effectively suppress or reduce negative electrode side reactions. Therefore, the all-solid-state battery 10 according to this disclosure can improve battery performance.

[0074] The first solid electrolyte layer 310 may have a first thickness TK1, and the second solid electrolyte layer 320 may have a second thickness TK2. The first thickness TK1 and the second thickness TK2 may be the same as or different from each other. In one or more embodiments, the first thickness TK1 may be greater than the second thickness TK2. For example, the first thickness TK1 may be about 1.1 to 5 times the second thickness TK2.

[0075] Reference Figure 1 and Figure 2 The positive electrode layer 100 and the first solid electrolyte layer 310 can form a positive electrode hybrid layer CSH. The negative electrode layer 200 and the second solid electrolyte layer 320 can form a negative electrode hybrid layer ASH. The positive electrode hybrid layer CSH can be stacked on the negative electrode hybrid layer ASH.

[0076] The negative electrode hybrid layer ASH and the positive electrode hybrid layer CSH can have different areas. For example, the area of ​​the negative electrode hybrid layer ASH can be larger than the area of ​​the positive electrode hybrid layer CSH. The positive electrode hybrid layer CSH can be completely or substantially superimposed on the negative electrode hybrid layer ASH.

[0077] In one or more embodiments of this disclosure, the first solid electrolyte layer 310 may have an area substantially the same as that of the positive electrode layer 100. The second solid electrolyte layer 320 may have an area substantially the same as that of the negative electrode layer 200.

[0078] For example, the positive electrode hybrid layer CSH can have a first width WI1 in the first direction D1. The negative electrode hybrid layer ASH can have a second width WI2 in the first direction D1. The first width WI1 can be smaller than the second width WI2. The positive electrode hybrid layer CSH can have a third width WI3 in the second direction D2. The negative electrode hybrid layer ASH can have a fourth width WI4 in the second direction D2. The third width WI3 can be smaller than the fourth width WI4.

[0079] The all-solid-state battery 10 according to this embodiment can be prepared / manufactured by forming a negative electrode hybrid layer ASH on a first carrier film, forming a positive electrode hybrid layer CSH on a second carrier film, and then stacking the negative electrode hybrid layer ASH and the positive electrode hybrid layer CSH.

[0080] Figure 3 The diagram illustrates an all-solid-state battery according to one or more embodiments of the present disclosure. Figure 1 A sectional view taken along line A-A'. No reference to the above will be provided. Figure 1 and Figure 2 The technical features discussed will be described in detail, and their differences will be discussed in more detail.

[0081] Reference Figure 3 The all-solid-state battery 10 may include gaskets GSK. The gaskets GSK may be disposed around (e.g., surrounding) the positive electrode hybrid layer CSH. The area difference between the negative electrode hybrid layer ASH and the positive electrode hybrid layer CSH may create a step difference (e.g., a gap in the first direction D1) on the side surfaces of the all-solid-state battery 10, which the gaskets GSK may fill. The gaskets GSK may be around (e.g., surrounding) the four side surfaces of the positive electrode hybrid layer CSH. For example, the thickness of the gaskets GSK may be substantially the same as the thickness of the positive electrode hybrid layer CSH.

[0082] The top surface of the second solid electrolyte layer 320 may include a first region in contact with the first solid electrolyte layer 310 and a second region in contact with the gasket GSK. The second region may be a peripheral region of the top surface of the second solid electrolyte layer 320. The second region may be around (e.g., surrounding) the first region.

[0083] Figure 4A cross-sectional view is shown illustrating a negative electrode for an all-solid-state battery according to one or more embodiments of the present disclosure. Figure 5 It shows Figure 4 A magnified view of part M. Figure 6 It shows Figure 4 A magnified view of part N. (Refer to...) Figures 4 to 6 The negative electrode for all-solid-state batteries according to this disclosure will be discussed in more detail.

[0084] The coating layer 220 may include carbon 221 and a first metal 222. In the coating layer 220, the amount of carbon 221 may be greater than the amount of the first metal 222. Relative to 100 parts by weight of the coating layer 220, carbon 221 may be present in an amount of about 50 parts by weight to about 99 parts by weight. Relative to 100 parts by weight of the coating layer 220, the first metal 222 may be present in an amount of about 1 part by weight to about 50 parts by weight.

[0085] The coating layer 220 may include at least one carbon selected from carbon black, acetylene black, furnace black, Ketjen black, and / or graphene. In one or more embodiments, the coating layer 220 may include a mixture of carbon black and silver (Ag).

[0086] In addition to carbon 221 and the first metal 222, the coating layer 220 may also include additives. The coating layer 220 may include at least one additive selected from, for example, binders, fillers, coating agents, dispersants and / or ionic conductive agents.

[0087] The adhesive included in the coating layer 220 may include at least one selected from styrene-butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride (PVdF), polyethylene, vinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile and / or polymethyl methacrylate.

[0088] The adhesive may be included in an amount of about 1 part by weight to about 30 parts by weight relative to 100 parts by weight of the coating layer 220. For example, the adhesive may be included in an amount of about 5 parts by weight to about 15 parts by weight relative to 100 parts by weight of the coating layer 220.

[0089] The functional layer 230 may be located between the negative electrode current collector 210 and the coating layer 220 (e.g., placed between the negative electrode current collector 210 and the coating layer 220). The functional layer 230 may include a second metal 231. The functional layer 230 may include an alloy of the second metal 231 and lithium. This may be because the lithium adsorbed in the functional layer 230 combines with the second metal 231 to form an alloy. The amount (content) of the second metal 231 in the functional layer 230 may be greater than the amount (content) of the first metal 222 in the coating layer 220. For example, the weight percentage of the second metal 231 in the functional layer 230 may be greater than the weight percentage of the first metal 222 in the coating layer 220. The amount (content) of the second metal 231 in the functional layer 230 may be the same as the amount (content) of the first metal 222 in the coating layer 220. For example, the weight percentage of the second metal 231 in the functional layer 230 may be equal to the weight percentage of the first metal 222 in the coating layer 220.

[0090] The thickness TH3 of the coating layer 220 can be greater than the thickness TH4 of the functional layer 230. The thickness TH3 of the coating layer 220 can be in the range of about 5 μm to about 10 μm. The thickness TH4 of the functional layer 230 can be in the range of about 30 nm to about 4 μm. For example, the thickness TH4 of the functional layer 230 can be in the range of about 50 nm to about 3.5 μm.

[0091] If (for example, when) the thickness TH4 of functional layer 230 is less than the range described above (e.g., from about 30 nm to about 4 μm), the ionic conductivity of lithium may not be improved, and lithium metal may form irregularly (e.g., deposited on) the negative electrode current collector 210, leading to dendrite formation. If (for example, when) the thickness TH4 of functional layer 230 is greater than the range described above (e.g., from about 30 nm to about 4 μm), the energy density of the all-solid-state battery will decrease, resulting in reduced cycle characteristics. Conversely, if (for example, when) the thickness TH4 of functional layer 230 falls within the range described above (e.g., from about 30 nm to about 4 μm), lithium metal can be uniformly (e.g., substantially uniformly) formed (e.g., deposited on) the deposition layer 240 described later (see [link to details]). Figure 7 Therefore, the lifespan characteristics of all-solid-state batteries can be improved. Furthermore, the functional layer 230 can induce excellent or suitable conductivity to produce excellent fast charging.

[0092] Both the first metal 222 of the coating layer 220 and the second metal 231 of the functional layer 230 may include a lithiophilic element. A lithiophilic element can refer to a metal exhibiting a high affinity for lithium. The lithiophilic element may not be lithium. A metal with a high affinity for lithium can refer to a metal on which lithium ions readily adsorb and on which lithium is uniformly (e.g., substantially uniformly) electrodeposited.

[0093] The first metal 222 and the second metal 231 can have high lithium diffusion coefficients. For example, each of the first metal 222 and the second metal 231 can have a diffusion coefficient of about 10. -14 cm 2 / s to approximately 10 -6 cm 2 The lithium diffusion coefficient is in the range of / s. However, this disclosure is not limited thereto. Each of the first metal 222 and the second metal 231 may have a high binding energy with lithium. For example, each of the first metal 222 and the second metal 231 may have a lithium binding energy of about 0.2 eV to about 0.5 eV. However, this disclosure is not limited thereto.

[0094] For example, the first metal 222 and the second metal 231 may each comprise at least one metal selected from gold (Au), magnesium (Mg), indium (In), titanium (Ti), gallium (Ga), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and / or zinc (Zn). The first metal 222 and the second metal 231 may be the same metal, but this disclosure is not limited thereto. In one or more embodiments, the first metal 222 and the second metal 231 may be different metals.

[0095] Since each of the coating layer 220 and the functional layer 230 includes a metal exhibiting a high affinity for lithium, lithium ions can be readily adsorbed onto the coating layer 220 and the functional layer 230. According to this disclosure, since the functional layer 230 is further included between the negative electrode current collector 210 and the coating layer 220, lithium can be uniformly (e.g., substantially uniformly) deposited in the deposition layer 240 between the negative electrode current collector 210 and the functional layer 230.

[0096] The particle size of the first metal 222 can be larger than that of the second metal 231. For example, both the first and second metals are in the form of particles, and the average particle size DM1 of the first metal 222 (particles) can be larger than the average particle size DM2 of the second metal 231 (particles). When the second metal 231 is formed (e.g., deposited) on the negative electrode current collector 210 in a sputtering process of the manufacturing / preparation process to be discussed, the second metal 231 can have a relatively small particle size. The average particle size DM1 of the first metal 222 can be in the range of about 30 nm to about 80 nm. The average particle size DM2 of the second metal 231 can be in the range of about 1 nm to about 20 nm.

[0097] Because the particle size of the first metal 222 is larger than that of the second metal 231, the surface roughness of the functional layer 230 can be smaller than that of the coating layer 220. For example, the coating layer 220 can have a surface roughness in the range of about 0.5 μm to about 1 μm. The functional layer 230 can have a surface roughness in the range of about 0.1 μm to about 0.4 μm.

[0098] The porosity of the coating layer 220 can be greater than that of the functional layer 230. The porosity of the coating layer 220 can refer to the ratio of the empty space in the coating layer 220 to the volume of the coating layer 220. The porosity of the functional layer 230 can refer to the ratio of the empty space in the functional layer 230 to the volume of the functional layer 230.

[0099] According to this disclosure, the functional layer 230 may be disposed between the negative electrode current collector 210 and the coating layer 220. The functional layer 230 may include a metal containing a lithium-affinity element. Since the functional layer 230 has a high affinity for lithium, it is possible to improve the lithium-ion conductivity that decreases in the direction from the coating layer 220 towards the negative electrode current collector 210. In summary, the electrical properties and lifetime characteristics of the all-solid-state battery can be improved.

[0100] Figure 7 A cross-sectional view illustrating a negative electrode for an all-solid-state battery according to one or more embodiments of the present disclosure is shown. In one or more embodiments below, the same references to the above will not be provided. Figures 4 to 6 The technical features discussed will be described in detail, and their differences will be discussed in more detail.

[0101] Reference Figure 7 A deposition layer 240 may be included between the negative electrode current collector 210 and the functional layer 230. The deposition layer 240 may include deposited lithium. If (e.g., when) the all-solid-state battery 10 is charged, the functional layer 230 may induce the growth of lithium metal within the deposition layer 240. The functional layer 230 may serve as a protective layer for the lithium metal and simultaneously (e.g., concurrently) suppress or reduce the deposition and growth of lithium dendrites.

[0102] According to this disclosure, a deposition layer 240 in which lithium is formed (e.g., deposited) can be disposed between the functional layer 230 and the negative electrode current collector 210. The presence of the deposition layer 240 can suppress or reduce dendrite deposition and growth. In summary, the electrical properties and lifetime characteristics of the all-solid-state battery can be improved.

[0103] The method for manufacturing an all-solid-state battery according to this disclosure will now be described. (The above description may be omitted.) Figures 2 to 6 This is a repetition of the technical features discussed earlier.

[0104] Reference Figure 1and Figure 2 A method for manufacturing an all-solid-state battery may include: forming a negative electrode hybrid layer ASH; forming a positive electrode hybrid layer CSH; and stacking the negative electrode hybrid layer ASH and the positive electrode hybrid layer CSH. The formation of the negative electrode hybrid layer ASH may include forming a functional layer 230 on a first surface of the negative electrode current collector 210 and forming a coating layer 220 on the functional layer 230. The functional layer 230 and the coating layer 220 may be sequentially stacked on the negative electrode current collector 210.

[0105] The formation of the functional layer 230 may include performing a physical deposition method. For example, a sputtering process may be used to form the functional layer 230. For example, the interior of the chamber may be maintained under vacuum or low pressure, and an inert gas may be introduced to generate plasma. Ions in the generated plasma may collide with the metal thin layer at high speed to eject metal particles. The ejected particles may be deposited on the negative electrode current collector 210 to form a thin layer. Thus, a functional layer 230 comprising metal particles can be formed. The metal thin layer may include at least one lithiophilic element selected from silver (Ag), gold (Au), magnesium (Mg), indium (In), titanium (Ti), gallium (Ga), platinum (Pt), palladium (Pd), silicon (Si), aluminum (Al), bismuth (Bi), tin (Sn), and / or zinc (Zn).

[0106] When using a sputtering process, the functional layer 230 can be uniformly (e.g., substantially uniformly) formed on the negative electrode current collector 210. Furthermore, the metal grain size of the functional layer 230 can be smaller than the metal grain size of the coating layer 220. Therefore, the surface roughness of the functional layer 230 can be smaller than the surface roughness of the coating layer 220.

[0107] Examples and comparative examples of this disclosure will be described below. However, the following embodiments are merely examples, and this disclosure is not limited to the one or more embodiments discussed.

[0108] Example 1 A 10 μm thick stainless steel (SUS) foil is prepared as the negative electrode current collector. A sputtering process is performed to form (e.g., deposit) silver (Ag) on ​​the top surface of the negative electrode current collector, thereby fabricating a functional layer. For example, ionized argon gas is introduced into a vacuum chamber to generate plasma. Argon particles in the plasma collide with the silver (Ag) foil at high speed to form (e.g., deposit) silver (Ag) particles on the top surface of the negative electrode current collector. The silver (Ag) particles in the functional layer have an average particle size of 10 nm. The thickness of the functional layer is 50 nm.

[0109] Silver (Ag) with an average particle size of 40 nm to 70 nm was prepared. Carbon black (CAS#1333-86-4), used as amorphous carbon, and silver (Ag) were mixed at a weight ratio of 85:15 to prepare a coating slurry. The coating slurry was then applied to the functional layer, and the mixture was dried to form a coating layer with a thickness of 10 μm.

[0110] As described above (for example, Figures 4 to 6 The negative electrode, solid electrolyte layer and positive electrode are stacked to manufacture an all-solid-state battery (as discussed in the embodiments).

[0111] A positive electrode layer comprising a positive electrode active material layer is prepared on a positive electrode current collector. An aluminum foil with a thickness of approximately 13 μm is prepared as the positive electrode current collector. The positive electrode active material layer comprises NCM as the positive electrode active material and Li as the solid electrolyte, which has a sulforaphite-germanium-type crystal structure, in a weight ratio of 85:13.5:0.5:1.0. PS Cl, carbon nanotubes (CNTs) as the conductive material and polyvinylidene fluoride (PVDF) as the binder. Details regarding the positive electrode and the solid electrolyte layer can be found above; this step is well-known to those skilled in the art and therefore will not be described in detail here.

[0112] Example 2 Except for the functional layer having a thickness of 1 μm, the negative electrode and the all-solid-state battery were prepared using essentially the same method as in Example 1.

[0113] Example 3 Except for the functional layer having a thickness of 3.5 μm, the negative electrode and the all-solid-state battery were prepared using essentially the same method as in Example 1.

[0114] Comparative Example 1 Without forming a functional layer, a coating layer is prepared by coating and drying a coating slurry on an SUS foil that serves as the negative electrode current collector. Except as described above (e.g., forming a coating layer on the negative electrode current collector without forming a functional layer), the negative electrode and the all-solid-state battery are prepared in essentially the same manner as in Example 1.

[0115] In summary, in Example 1, a 10 μm thick stainless steel (SUS) foil was used as the negative electrode current collector, which had a functional layer of silver (Ag) particles (10 nm average particle size) deposited to a thickness of 50 nm via sputtering. A coating slurry prepared by mixing silver (Ag) particles (40 nm to 70 nm average particle size) and carbon black in a weight ratio of 85:15 was applied and dried to form a 10 μm thick coating layer. This negative electrode was used together with a solid electrolyte layer and a positive electrode to fabricate an all-solid-state battery. In contrast, Examples 2 and 3 changed the thickness of the functional layer to 1 μm and 3.5 μm, respectively, while Comparative Example 1 completely omitted the functional layer and applied the coating slurry directly to the SUS foil.

[0116] Table 1 shows a comparison between the negative electrodes according to Examples 1 to 3 and Comparative Example 1.

[0117] Table 1

[0118] Experimental Example 1: SEM Analysis The cross-section of the negative electrode of the all-solid-state battery fabricated in Example 3 was analyzed using scanning electron microscopy (SEM). Figure 8 SEM images of the negative electrode for an all-solid-state battery according to one or more embodiments of the present disclosure are shown. Figure 9 SEM images of the functional layer of the negative electrode according to one or more embodiments of the present disclosure are shown.

[0119] Reference Figure 8 and Figure 9 It can be observed that the functional layer 230 is satisfactorily formed between the negative electrode current collector 210 and the coating layer 220. It can be observed that the functional layer 230 is formed with a thickness TH4 of about 3.5 μm.

[0120] Experimental Example 2: Evaluation of Cyclic Characteristics The cycle characteristics of each of the all-solid-state batteries manufactured in Example 1, Example 3, and Comparative Example 1 were evaluated. For example, at 45°C and 0.5 mA·cm⁻¹... -2 Current density, 2 mA·hcm -2 The rate of capacity change was measured relative to the number of charge-discharge cycles (cycle number, #) during repeated charge and discharge cycles under conditions of 130 cycles and a cutoff voltage of 1V. The rate of capacity change was defined as the ratio of the capacity reduction after 130 cycles to the initial capacity.

[0121] Reference Figure 10The capacity change rate of Example 1 was 55.38%, and that of Example 3 was 77.99%. In contrast, the capacity change rate of Comparative Example 1 was 87.36%, showing a higher rate compared to the examples. It can be estimated that the all-solid-state battery including the functional layer exhibits a relatively small capacity change rate during repeated charge-discharge cycles. This is likely because the functional layer increases the activity of lithium deposition and promotes substantially uniform lithium deposition, resulting in stable charging and discharging.

[0122] In summary, it can be determined that, compared with the all-solid-state battery according to Comparative Example 1, the all-solid-state batteries according to Examples 1 and 3 show a significant improvement in lifetime characteristics.

[0123] Experimental Example 3: Measurement of Initial Capacity Efficiency For each of the all-solid-state batteries manufactured in Examples 1, 3, and Comparative Example 1, the initial capacity efficiency (ICE) was measured as follows. The all-solid-state battery was charged at a constant current of 0.05C to an upper limit voltage of 4.25V at a temperature of 45°C, and then discharged at a constant current of 0.05C to a cutoff voltage of 2.5V. The initial charge capacity and initial discharge capacity were measured, and the results are shown in Table 2. In Table 2, the initial capacity efficiency (%) is expressed by Equation 1.

[0124] Mathematical Equation 1 Initial capacity efficiency (%) = (Initial discharge capacity / Initial charge capacity) × 100 Table 2

[0125] Referring to Table 2, in Example 1, the initial charge capacity was 236.19 mAh / g, the initial discharge capacity was 196.33 mAh / g, and the initial capacity efficiency was 83.12%. In Example 3, the initial charge capacity was 235.87 mAh / g, the initial discharge capacity was 195.21 mAh / g, and the initial capacity efficiency was 83.76%. In contrast, in Comparative Example 1, the initial charge capacity was 235.50 mAh / g, the initial discharge capacity was 195.51 mAh / g, and the initial capacity efficiency was 83.02%. The initial capacity efficiency of Comparative Example 1 is lower than that of Example 1 and Example 3. Therefore, it can be seen that the all-solid-state battery including the functional layer has improved initial charge efficiency.

[0126] In summary, it can be determined that, compared with the all-solid-state battery according to Comparative Example 1, the all-solid-state batteries according to Examples 1 and 3 show a significant improvement in lifetime characteristics.

[0127] Experimental Example 4: SEM Measurement (Inspection of Deposition Layers) Following the capacity evaluation based on Experimental Example 3, the cross-section of the negative electrode of the all-solid-state battery was analyzed using scanning electron microscopy (SEM). Figure 11A SEM images of the negative electrode for an all-solid-state battery according to Example 1 are shown. Figure 11B SEM images of the negative electrode for an all-solid-state battery, taken according to other examples, are shown.

[0128] Reference Figure 11A It can be observed that the deposition layer 240 is satisfactorily formed between the negative electrode current collector 210 and the functional layer 230. It can be found that lithium metal is uniformly (e.g., substantially uniformly) deposited in the deposition layer 240.

[0129] Reference Figure 11B A functional layer 230 is formed between the coating layer 220 and the solid electrolyte layer 300. A deposited layer 240 can be observed formed between the functional layer 230 and the solid electrolyte layer 300. In this case, the deposited layer 240 exhibits a dendritic structure.

[0130] Experimental Example 5: XRD Analysis After 10 charge-discharge cycles of the all-solid-state battery according to Example 1, the battery was disassembled and subjected to X-ray diffraction (XRD) analysis to examine the structure of the negative electrode. Figure 12 The XRD analysis results of the negative electrode for an all-solid-state battery according to Example 1 are shown. (Refer to...) Figure 12 It can be observed that a LiAg structure is found near the (28) peak and a Li9Ag4 structure is found near the (40) peak. Therefore, it can be determined that the functional layer includes silver (Ag) as a lithiophilic element, which satisfactorily reacts with lithium to form an alloy.

[0131] The negative electrode for an all-solid-state battery according to this disclosure may include a functional layer between the negative electrode current collector and the coating layer. The functional layer may include a lithium-philic metal, and the amount of metal in the functional layer may be greater than the amount of metal in the coating layer. Furthermore, the thickness of the functional layer in the negative electrode is configured in the range of about 30 nm to about 4 μm, so that lithium metal is uniformly formed on the deposited layer during charging. Therefore, due to the protection of the deposited layer, the lifetime characteristics of the all-solid-state battery including such a negative electrode can be improved. The presence of a functional layer with a high affinity for lithium can cause an improvement in the ionic conductivity of lithium ions. In addition, the functional layer can cause excellent or suitable conductivity to produce excellent fast charging. In summary, the electrical properties and lifetime characteristics of the all-solid-state battery can be improved.

[0132] The battery, battery management system in the battery, its manufacturing equipment, or any other related device / apparatus or component according to embodiments of the present disclosure described herein can be implemented using any suitable hardware, firmware (e.g., application-specific integrated circuit), software, or a combination of software, firmware, and hardware. For example, various components of the device can be formed on an integrated circuit (IC) chip or a separate IC chip. Furthermore, various components of the device can be implemented on a flexible printed circuit film, a tape-on-a-chip (TCP), a printed circuit board (PCB), or formed on a substrate. Additionally, various components of the device can be processes or threads running on one or more computing devices and one or more processors, executing computer program instructions and interacting with other system components to perform the various functions described herein. The computer program instructions are stored in memory that can be implemented in the computing device using standard memory devices, such as random access memory (RAM). The computer program instructions can also be stored in other non-transitory computer-readable media, such as CD-ROMs, flash drives, etc. Furthermore, those skilled in the art will recognize that the functions of various computing devices can be combined or integrated into a single computing device, or the functions of a particular computing device can be distributed across one or more other computing devices without departing from the scope of embodiments of the present disclosure.

[0133] In this disclosure, various suitable features of the disclosed embodiments may be combined in part or in whole or in combination with each other, and may be technically interlocked and operated in various suitable ways, and unless otherwise stated or implied, the various embodiments may be implemented independently or in combination with each other in any suitable manner.

[0134] As used herein, the terms “substantially,” “about,” and similar terms are used as approximate terms rather than terms of degree and are intended to account for the inherent biases of measured or calculated values ​​that would be recognized by one of ordinary skill in the art. Taking into account the measurements discussed and the errors associated with the measurement of a particular quantity (i.e., the limitations of the measurement system), “about” or “approximately” as used herein includes the stated value and means within an acceptable range of deviation for the particular value as determined by one of ordinary skill in the art. For example, “about” may mean within one or more standard deviations, or within ±30%, ±20%, ±10%, ±5% of the stated value.

[0135] Furthermore, any numerical range described herein is intended to include all subranges with the same numerical precision contained within the described range. For example, the range "1.0 to 10.0" is intended to include all subranges (inclusive) between the described minimum value of 1.0 and the described maximum value of 10.0, i.e., a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as 2.4 to 7.6. Any maximum numerical limit described herein is intended to include all lower numerical limits contained therein, and any minimum numerical limit described in this specification is intended to include all higher numerical limits contained therein. Therefore, the applicant reserves the right to amend this specification and claims to expressly describe any subranges contained within the scope expressly described herein.

[0136] While this disclosure has been described in conjunction with what is now considered to be one or more embodiments, it will be understood that the disclosure is not limited to the disclosed embodiments, but is intended to cover one or more suitable modifications and equivalent arrangements included within the spirit and scope of the appended claims. Therefore, the foregoing embodiments should be understood as exemplary and not as limiting the disclosure in any way.

Claims

1. A negative electrode, the negative electrode comprising: a negative electrode current collector; a coating layer on the negative electrode current collector and comprising carbon and a first metal; and a functional layer between the negative electrode current collector and the coating layer, wherein the functional layer comprises a second metal, wherein each of the first metal and the second metal comprises at least one lithiumophilic element selected from among silver, gold, magnesium, indium, titanium, gallium, platinum, palladium, silicon, aluminum, bismuth, tin, and zinc, and wherein the negative electrode is a negative electrode for a full solid-state battery. A content of the second metal in the functional layer is greater than a content of the first metal in the coating layer.

2. The negative electrode according to claim 1, wherein The functional layer comprises the second metal sputter-deposited on the negative electrode current collector.

3. The negative electrode according to claim 1, wherein The lithium diffusion coefficient of each of the first metal and the second metal is in the range of 10 -14 cm 2 / s to 10 -6 cm 2 / s.

4. The negative electrode according to claim 1, wherein The first metal and the second metal are each in the form of particles, and an average particle diameter of the particles of the second metal is smaller than an average particle diameter of the particles of the first metal.

5. The negative electrode according to claim 1, wherein A surface roughness of the functional layer is smaller than a surface roughness of the coating layer.

6. The negative electrode according to claim 1, wherein The functional layer comprises an alloy of the second metal and lithium.

7. The negative electrode according to claim 1, wherein A thickness of the coating layer is greater than a thickness of the functional layer.

8. The negative electrode according to claim 1, wherein The thickness of the functional layer is in a range of 30 nm to 4 μm.

9. The negative electrode according to claim 1, wherein 10. The negative electrode according to claim 1, further comprising a deposition layer between the negative electrode current collector and the functional layer, the deposition layer comprising lithium deposited by an initial charge-discharge cycle. wherein, 11. A battery, the battery comprising: a positive electrode; a negative electrode opposite to the positive electrode; and a solid electrolyte layer between the positive electrode and the negative electrode, wherein the negative electrode comprises: a negative electrode current collector; a coating layer on the negative electrode current collector; and a functional layer between the negative electrode current collector and the coating layer, wherein the coating layer comprises carbon and a first metal, wherein the functional layer comprises a second metal, wherein each of the first metal and the second metal is a lithiumophilic metal, wherein a thickness of the coating layer is greater than a thickness of the functional layer, wherein the thickness of the functional layer is in a range of 30 nm to 4 μm, and wherein the battery is a full solid-state battery. An average particle diameter of the second metal is smaller than an average particle diameter of the first metal. Each of the first metal and the second metal comprises at least one lithiumophilic element selected from among silver, gold, magnesium, indium, titanium, gallium, platinum, palladium, silicon, aluminum, bismuth, tin, and zinc.

12. The battery of claim 11, wherein, A surface roughness of the functional layer is smaller than a surface roughness of the coating layer.

13. The battery of claim 12, wherein, 15. The battery according to claim 11, further comprising a deposition layer between the negative electrode current collector and the functional layer, 14. The battery of claim 11, wherein, the deposition layer comprising lithium deposited by an initial charge-discharge cycle.

17. A method, the method comprising the steps of: wherein forming a functional layer on a first surface of a negative electrode current collector; and 16. The battery of claim 11, wherein, The lithium diffusion coefficient of each of the first metal and the second metal is in the range of 10 -14 cm 2 / s to 10 -6 cm 2 / s. forming a coating layer on the functional layer, wherein the coating layer comprises carbon and a first metal, wherein the step of forming the functional layer comprises performing a sputtering process to form a second metal on the first surface of the negative electrode current collector, ​ ​ ​ wherein each of the first metal and the second metal includes at least one lithiumophilic element selected from among silver, gold, magnesium, indium, titanium, gallium, platinum, palladium, silicon, aluminum, bismuth, tin, and zinc, and wherein the method is a method for manufacturing an all-solid-state battery.

18. The method of claim 17, wherein, The first metal and the second metal are each in the form of particles, and the average particle diameter of the particles of the second metal is smaller than the average particle diameter of the particles of the first metal.

19. The method of claim 17, wherein, The content of the second metal in the functional layer is greater than the content of the first metal in the coating layer.

20. The method of claim 17, wherein, The surface roughness of the functional layer is smaller than the surface roughness of the coating layer. The surface roughness of the functional layer is smaller than the surface roughness of the coating layer.

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