All-solid-state battery and method of manufacturing the same

Abstract

All-solid-state battery and method of manufacturing the same. The all-solid-state battery includes a multilayer structure, a first cover layer, and a second cover layer opposite the first cover layer. The multilayer structure includes a solid electrolyte layer including a solid electrolyte, a positive electrode layer provided on a first side of the solid electrolyte layer, a portion of the positive electrode layer extending to a first edge of the solid electrolyte layer, a first edge layer provided on an area of the first side of the solid electrolyte layer, a negative electrode layer provided on a second side of the solid electrolyte layer, and a second edge layer provided on an area of the second side of the solid electrolyte layer. Also, at least one of the first cover layer, the second cover layer, the first edge layer, or the second edge layer includes an oxide including a pyrochlore crystalline material.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to, and all rights arising therefrom, of Korean Patent Application No. 10-2025-0186657 filed on December 1, 2025, Korean Patent Application No. 10-2025-0143043 filed on September 30, 2025, and Korean Patent Application No. 10-2024-0177900 filed on December 3, 2024, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] This disclosure relates to all-solid-state batteries and methods for manufacturing all-solid-state batteries. Background Technology

[0004] Many existing lithium-ion batteries use liquid electrolytes, many of which include flammable organic solvents. Therefore, such batteries are susceptible to overheating and potential fires in the event of a short circuit. To address these operational safety concerns, all-solid-state batteries using solid electrolytes instead of liquid electrolytes are of interest.

[0005] Among solid electrolytes used in all-solid-state batteries, garnet-type oxide solid electrolytes are materials with high ionic conductivity and are considered key materials for oxide all-solid-state batteries due to their excellent chemical stability with lithium.

[0006] To improve the energy density in all-solid-state batteries, which include solid electrolytes, the battery cells are multilayered. During multilayering, capping layers are provided on the top and bottom sides of the stacking direction of the all-solid-state battery, or margin layers are required to protect the internal cell cells. Summary of the Invention

[0007] It offers all-solid-state batteries, which effectively protect the internal cell units from external influences and improve energy density and rate performance.

[0008] Provides a method for manufacturing all-solid-state batteries.

[0009] Other 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 embodiments presented in this disclosure.

[0010] According to one aspect of this disclosure, an all-solid-state battery includes a multilayer structure, a first capping layer on a first outermost layer of the multilayer structure in a stacking direction, and a second capping layer disposed on a side opposite to the first capping layer and stacked on a second outermost layer of the multilayer structure. The multilayer structure includes: a solid electrolyte layer comprising a solid electrolyte; a positive electrode layer provided on a first side of the solid electrolyte layer, wherein a portion of the positive electrode layer extends to a first edge of the solid electrolyte layer; and a first edge layer provided on a region of the solid electrolyte layer on the first side where the positive electrode layer is not provided (or is absent), the region of the solid electrolyte layer on the first side including a region adjacent to a second edge of the solid electrolyte opposite to the first edge. The multilayer structure further includes a negative electrode layer provided on a second side opposite to the solid electrolyte layer, wherein a portion of the negative electrode layer extends to a second edge of the solid electrolyte layer; and a second edge layer disposed on a region of the solid electrolyte layer on the second side where the negative electrode layer is not provided (or is absent), the region of the solid electrolyte layer on the second side including a region adjacent to the first edge of the solid electrolyte. Furthermore, at least one of the first cover layer, the second cover layer, the first edge layer, or the second edge layer comprises an oxide, said oxide comprising pyrochlore crystalline material.

[0011] The pyrochlore crystal material may be a compound represented by Formula 1:

[0012] Formula 1

[0013] (La 1-a B a ) 2+nx Zr 2-(n+1)x C x O7

[0014] In Equation 1,

[0015] B is one or more trivalent cations.

[0016] C is one or more tetravalent cations, one or more pentavalent cations, or one or more hexavalent cations.

[0017] 0 ≤ a < 1, 0 ≤ x < 0.66, and

[0018] n = (oxidation number of C) - (oxidation number of Zr).

[0019] In Formula 1, B may include scandium (Sc), yttrium (Y), aluminum (Al), gallium (Ga), or indium (In), and C may include tungsten (W), niobium (Nb), bismuth (Bi), antimony (Sb), or tantalum (Ta).

[0020] The pyrochlore crystalline material represented by Formula 1 can be a compound represented by Formula 2.

[0021] Formula 2

[0022] La 2+x Zr 2-2x Ta x O7

[0023] In Equation 2, 0 ≤ x < 0.66.

[0024] The peaks in the X-ray diffraction (XRD) spectrum of the oxide may appear at diffraction angles (2θ) of about 27.5°–29°, about 32°–33.5°, about 46.5°–48°, and about 55°–56.5°.

[0025] The oxide may further include amorphous materials.

[0026] The content of the pyrochlore crystalline material in the oxide can range from about 50 parts by weight to about 99.9 parts by weight, relative to the total weight of 100 parts by weight of the oxide.

[0027] The weight ratio of lanthanum to lithium in at least one of the first capping layer, the second capping layer, the first edge layer, and the second edge layer is G. La / G Li It can be in the range of approximately 3 to approximately 5.

[0028] The oxide may have a lower ionic conductivity than the solid electrolyte. The oxide may have a conductivity of 1.0 × 10⁻⁶. -8 Siemens ion conductivity per centimeter (S / cm) or less.

[0029] At least one of the first cover layer, the second cover layer, the first edge layer, and the second edge layer may have a density less than 1.0 × 10⁻⁶. -7 Electron conductivity in S / cm.

[0030] The all-solid-state battery may further include a third edge layer disposed on an extension plane of the solid electrolyte layer and having a structure that partially overlaps with the first edge layer and the second edge layer.

[0031] The lanthanum to lithium weight ratio G of at least one of the first capping layer, the second capping layer, the first edge layer, and the second edge layer La / G Li The weight ratio of lanthanum to lithium in the solid electrolyte layer can be less than G. La / G Li .

[0032] According to one aspect of this disclosure, a method for manufacturing an all-solid-state battery includes:

[0033] Prepare a positive electrode structure having a first edge layer that does not overlap with the positive electrode layer to form a composition;

[0034] A negative electrode structure is prepared having a second edge layer that does not overlap with the negative electrode layer to form the composition;

[0035] A multilayer structure is formed having a solid electrolyte forming composition disposed between the positive electrode structure and the negative electrode structure;

[0036] A first cover layer is provided on the first outermost layer of the multilayer structure to form a composition;

[0037] A second cover layer is provided on the second outermost layer of the multilayer structure to form a composition for providing a stack, the second outermost layer being disposed opposite to the first outermost layer of the multilayer structure; and

[0038] Heat-treat the stack.

[0039] The all-solid-state battery includes the multilayer structure, a first cover layer on the first outermost layer of the multilayer structure in the stacking direction, and a second cover layer disposed opposite to the first outermost layer and stacked on the second outermost layer.

[0040] The multilayer structure includes: a solid electrolyte layer comprising a solid electrolyte; a positive electrode layer provided on a first side of the solid electrolyte layer, wherein a portion of the positive electrode layer extends to a first edge of the solid electrolyte layer; a first edge layer provided on a region of the solid electrolyte layer on the first side where the positive electrode layer is not provided (or is absent), the region of the solid electrolyte layer on the first side including a region near a second edge of the solid electrolyte; and a negative electrode layer provided on a second side of the solid electrolyte layer, wherein a portion of the negative electrode layer extends to a second edge of the solid electrolyte layer, and a second edge layer provided on a region of the solid electrolyte layer on the second side where the negative electrode layer is not provided (or is absent), the region of the solid electrolyte layer on the second side including a region near a first edge of the solid electrolyte. Furthermore, at least one of the first capping layer, the second capping layer, the first edge layer, or the second edge layer comprises an oxide, the oxide comprising a pyrochlore crystalline material.

[0041] The heat treatment can be carried out at a temperature of about 200°C to about 700°C, and the heat treatment can be carried out under a pressure of about 5 MPa to about 300 MPa.

[0042] At least one of the first edge layer forming composition, the second edge layer forming composition, the first cover layer forming composition, and the second cover layer forming composition may include pyrochlore crystal material, pyrochlore crystal material precursor, or a combination thereof.

[0043] At least one of the first edge layer forming composition, the second edge layer forming composition, the first capping layer forming composition, and the second capping layer forming composition may further include an amorphous material, an amorphous material precursor, or a combination thereof.

[0044] The solid electrolyte forming composition may include garnet-type solid electrolytes, garnet-type solid electrolyte precursors, or combinations thereof.

[0045] The weight ratio G of lanthanum to lithium of at least one of the first edge layer forming composition, the second edge layer forming composition, the first capping layer forming composition, and the second capping layer forming composition. La / G Li The lanthanum-to-lithium weight ratio G of the solid electrolyte forming composition may be less than that of the solid electrolyte forming composition. La / G Li . Attached Figure Description

[0046] The above and other aspects, features, and advantages of some embodiments of this disclosure will become clearer from the following description taken in conjunction with the accompanying drawings, wherein:

[0047] Figure 1 A schematic perspective view illustrating the structure of a multilayer (multi-layer) ceramic battery according to an embodiment;

[0048] Figure 2 A schematic cross-sectional view illustrating the structure of the multilayer ceramic battery according to an embodiment;

[0049] Figure 3 A schematic cross-sectional view illustrating the structure of a multilayer ceramic battery;

[0050] Figure 4A A cross-sectional view illustrating the structure of a multi-layered unit cell battery.

[0051] Figure 4B A schematic plan view illustrating the structure of the positive electrode, including the positive electrode layer and the first edge layer;

[0052] Figure 4C A schematic plan view illustrating the structure of the negative electrode, including the negative electrode layer and the second edge layer;

[0053] Figure 4D A schematic plan view illustrating the structure of the solid electrolyte, including the solid electrolyte layer and the third edge layer;

[0054] Figure 4E A schematic exploded perspective view illustrating the stacked structure of an all-solid-state battery; and

[0055] Figure 5 The X-ray diffraction (XRD) spectra of the oxides of Example 1 and Comparative Example 1 are shown. Detailed Implementation

[0056] The embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings, wherein the same reference numerals always refer to the same elements. In this respect, the embodiments may take different forms and should not be construed as limited to the description set forth herein. Therefore, the embodiments are described below only with reference to the accompanying drawings to illustrate aspects.

[0057] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the inventive concept. Expressions used in the singular include plural expressions unless they have a distinct meaning in the context. As used herein, it will be understood that terms such as “comprising,” “having,” and “including” are intended to indicate the presence of features, quantities, steps, actions, components, parts, ingredients, materials, or combinations thereof disclosed in the specification, and are not intended to exclude the possibility that one or more other features, quantities, steps, actions, components, parts, ingredients, materials, or combinations thereof may be present or added. Depending on the context, the symbol “ / ” as used herein may be interpreted as “and” or “or.”

[0058] In the accompanying drawings, the thickness of layers and regions is exaggerated or reduced for clarity. Throughout the specification, the same reference numerals in the drawings denote the same elements. Throughout the specification, it will be understood that when a component such as a layer, film, region, or plate is referred to as being "on" another component, the component may be directly on said other component, or an intermediate component may be present on it.

[0059] It will be understood that although the terms “first,” “second,” “third,” etc., may be used herein to describe various elements, components (components), regions, layers, and / or parts, these elements, components (components), regions, layers, and / or parts should not be limited by these terms. These terms are used only to distinguish one element, component (component), region, layer, or part from another element, component (component), region, layer, or part. Therefore, without departing from the teachings herein, the terms “first element,” “component (component),” “region,” “layer,” or “part” discussed below may be referred to as a second element, component (component), region, layer, or part.

[0060] The terminology used herein is for the purpose of describing particular embodiments only and is not restrictive. As used herein, the singular forms “a (indefinite article, a, an)” and “the (definite article)” are intended to include the plural forms, including “at least one (a)”, unless the context clearly states otherwise. Thus, reference to the element “(a)” followed by “the (the)” in the claims includes one element as well as multiple elements.

[0061] As used herein, “about” or “approximately” includes the stated value and means within an acceptable range of deviations from the specific value, as determined by one of ordinary skill in the art taking into account the measurement in question and the errors associated with the measurement of the specific quantity (i.e., limitations of the measurement system). For example, “about” may mean within one or more standard deviations relative to the stated value, or within ±10% or ±5%.

[0062] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. It will be further understood that terms such as those defined in common dictionaries shall be interpreted as having a meaning consistent with their meaning in the context of the relevant field and in this disclosure, and shall not be interpreted in an idealized or overly formal sense unless expressly defined herein.

[0063] Exemplary embodiments are described herein with reference to cross-sectional views that serve as schematic representations of idealized embodiments. Thus, variations in shape from the illustrations are expected due to factors such as manufacturing techniques and / or tolerances. Therefore, the embodiments described herein should not be construed as limited to the specific shapes of the regions shown herein, but rather include deviations in shape, for example, due to manufacturing processes. For instance, regions illustrated or described as flat may typically have rough and / or non-linear characteristics. Furthermore, acute angles shown may be rounded. Therefore, the regions shown in the figures are schematic in nature, and their shapes are not intended to illustrate the precise shapes of the regions nor to limit the scope of the claims.

[0064] As used herein, the term “metal” includes all metals and metalloids such as silicon and germanium in elemental or ionic states, and the term “alloy” refers to a composite of two or more metals.

[0065] As used herein, the term "positive electrode active material" refers to a positive electrode material that can undergo lithiation and delithiation, and the term "negative electrode active material" refers to a negative electrode material that can undergo lithiation and delithiation.

[0066] As used herein, the term “lithiation” refers to the process of adding lithium to a positive or negative electrode active material, and the term “delithiation” refers to the process of removing lithium from a positive or negative electrode active material.

[0067] As used herein, the term “charging” refers to the process of providing electrochemical energy to a battery, and the term “discharging” refers to the process of removing electrochemical energy from a battery.

[0068] As used herein, the terms “positive electrode” and “negative electrode” refer to the electrode at which electrochemical reduction and lithiation occur during the discharge process, and the terms “negative electrode” and “negative electrode” refer to the electrode at which electrochemical oxidation and delithiation occur during the discharge process.

[0069] As used herein, the term "particle size" refers to the average diameter when the particle is spherical and to the average major axis length when the particle is non-spherical. The particle size can be measured using a particle size analyzer (PSA). "Particle size" is, for example, the average particle size. Unless otherwise explicitly stated, the average particle size is the median particle size (D50). The median particle size (D50) refers to the particle size corresponding to 50% of the cumulative value when calculating the particle size from the particle with the smallest particle size in a cumulative distribution curve in which particles are accumulated in order of particle size from smallest to largest. The cumulative value can be, for example, the cumulative volume. The median particle size (D50) can be measured, for example, by laser diffraction. As used herein, the term "D10" refers to the diameter of a particle having 10% by volume of the cumulative volume in the particle size distribution, and the term "D90" refers to the diameter of a particle having 90% by volume of the cumulative volume in the particle size distribution.

[0070] Alternatively, particle size can be measured using a scanning electron microscope. Particle size is determined as the average of 30 or more randomly selected particles with a size of 1 μm or larger, excluding fine particles. The average particle size of the positive electrode active material can be measured, for example, using laser diffraction. More specifically, after dispersing the positive electrode active material in a solution, the material can be introduced into a commercially available laser diffraction particle size measurement device (e.g., Microtrac MT 3000) and irradiated with ultrasound at an output of 28 kHz and 60 W. The average particle size (D50) can then be calculated based on 50% of the particle size distribution in the measurement device.

[0071] The all-solid-state battery according to the embodiments and the method of manufacturing the same will be described in more detail below.

[0072] Solid-state batteries can be used in electronic devices, vehicles, and other applications, but they are also suitable for other uses. There are no particular limitations on solid-state batteries, and they can be, for example, lithium-ion batteries or lithium-air batteries.

[0073] There are no particular limitations on all-solid-state batteries, and they can be, for example, multilayer ceramic (MLC) batteries. These batteries will be described in more detail below.

[0074] The all-solid-state battery according to the embodiments may include a multilayer structure, a first cover layer on a first outermost layer of the multilayer structure in a stacking direction, and a second cover layer disposed opposite to the first outermost layer and stacked on a second outermost layer.

[0075] Multi-layer structures may include:

[0076] Including a solid electrolyte layer containing a solid electrolyte.

[0077] A positive electrode layer is provided on a first side of the solid electrolyte layer, wherein a portion of the positive electrode layer extends to a first edge of the solid electrolyte layer.

[0078] A first edge layer is provided on a region on the first side of the solid electrolyte layer in which the positive electrode layer is not present, the region on the first side of the solid electrolyte layer including a region adjacent to a second edge of the solid electrolyte opposite to the first edge.

[0079] A negative electrode layer is provided on the opposite second side of the solid electrolyte layer, wherein a portion of the negative electrode layer extends to the second edge of the solid electrolyte layer, and

[0080] A second edge layer is provided on a region on the second side of the solid electrolyte layer in which the negative electrode layer is not present, the region on the second side of the solid electrolyte layer including a region close to the first edge of the solid electrolyte.

[0081] In this disclosure, the edge layer of an all-solid-state battery can refer to the peripheral portion of the electrode layer on which no electrodes are printed, forming the outer periphery of a cell, which can be used to protect the interior of the cell from the influence of the external environment, and can also perform the function of insulating the positive and negative electrodes.

[0082] In this disclosure, the first and second capping layers of an all-solid-state battery refer to the uppermost and lowermost layers in a multilayer structure in which the positive electrode layer, solid electrolyte layer, and negative electrode layer are sequentially stacked to form multiple layers, and the first and second capping layers together with the first and second edge layers form the outer periphery of the cell and are used to protect the interior of the cell from the influence of the external environment.

[0083] The all-solid-state battery according to the embodiments will be described in more detail with reference to the accompanying drawings.

[0084] Figure 1 This is a schematic perspective view illustrating an all-solid-state battery according to one embodiment. Figure 2 and 3This is a cross-sectional view of an all-solid-state battery according to another embodiment. The all-solid-state battery may include, for example, an MLC battery.

[0085] Reference Figure 1 The all-solid-state battery 100 may include external electrodes 112 and 114 connected thereto.

[0086] Reference Figure 1 , 2 In the all-solid-state battery 100, the opposite sides facing each other in the thickness direction (T-axis direction) can be defined as the first side and the second side, and the sides connected to the first side and the second side and facing each other in the length direction (L-direction) can be defined as the third side and the fourth side.

[0087] The all-solid-state battery 100 may include a multilayer structure, a first cover layer 160a stacked on a first outermost layer of the multilayer structure in a stacking direction, and a second cover layer 160b disposed on the opposite side of the first outermost layer and stacked on a second outermost layer.

[0088] A solid electrolyte layer 130 may be disposed between the positive electrode layer 120 and the negative electrode layer 140 in the stacking direction. In the all-solid-state battery 100, multiple positive electrode layers 120 and multiple negative electrode layers 140 may be alternately disposed in the stacking direction, and multiple solid electrolyte layers 130 may be disposed between the alternately disposed positive electrode layers 120 and negative electrode layers 140 in the stacking direction. The all-solid-state battery 100 may be manufactured by: alternately arranging multiple positive electrode layers 120 and multiple negative electrode layers 140 in the stacking direction, inserting multiple solid electrolyte layers 130 between the alternately arranged positive electrode layers 120 and negative electrode layers 140 to prepare a multilayer structure as an electrode-electrolyte stack, and sintering the multilayer structure together.

[0089] A multi-layered cell can have the following characteristics: Figure 4A The cross-sectional structure shown is illustrated. A unit cell may include: a solid electrolyte layer 130 including a solid electrolyte, a positive electrode layer 120 provided on a first side of the solid electrolyte layer 130, and a negative electrode layer 140 provided on a second side of the solid electrolyte layer 130.

[0090] A portion of the positive electrode layer 120 may extend to a first edge of the solid electrolyte layer 130, and a first edge layer 150' may be provided in a region on a first side of the solid electrolyte layer in which the positive electrode layer 120 is substantially not provided (see [reference]). Figure 4BThe area of ​​the first edge layer 150' relative to the total area of ​​100% of the first edge layer 150' and the positive electrode layer 120 can range from about 5% to about 30%. The positive electrode overlap area where the first edge layer 150' overlaps with the positive electrode layer 120 relative to the total area of ​​100% of the first edge layer 150' and the positive electrode layer 120 can range from 0% to about 3%, from about 0.01% to about 3%, or from about 0.1% to about 3%. In this disclosure, the area where the positive electrode layer 120 is not formed (or does not exist) refers to the area of ​​the first edge layer 150'. When the area of ​​the first edge layer 150' is within the above ranges, an all-solid-state battery capable of effectively protecting the internal cell from external influences and improving energy density and rate characteristics can be realized and manufactured. The first edge layer 150' can be configured to be substantially coplanar with the positive electrode layer 120. The first edge layer 150' may be disposed on the first side of the solid electrolyte layer 130 and has a thickness substantially equal to that of the positive electrode layer 120.

[0091] A portion of the negative electrode layer 140 may extend to the second edge of the solid electrolyte layer 130, and the second edge layer 150''' may be provided in the region on the second side of the solid electrolyte layer 130 where the negative electrode layer 140 is substantially not disposed (see...). Figure 4C The area of ​​the second edge layer 150''' relative to the total area of ​​100% of the second edge layer 150''' and the negative electrode layer 140 can range from about 5% to about 30%. The negative electrode overlap area where the second edge layer 150''' overlaps with the negative electrode layer 140 relative to the total area of ​​100% of the second edge layer 150''' and the negative electrode layer 140 can range from 0% to about 3%, from about 0.01% to about 3%, or from about 0.1% to about 3%. In this disclosure, the area where the negative electrode layer 140 is not provided (or does not exist) refers to the area of ​​the second edge layer 150'''. When the area of ​​the second edge layer 150''' is within the above-mentioned ranges, an all-solid-state battery capable of effectively protecting the internal cell from external influences and improving energy density and rate characteristics can be realized or manufactured. The second edge layer 150''' can be configured to be substantially coplanar with the negative electrode layer 140. The second edge layer 150''' may be disposed on the second side of the solid electrolyte layer 130 and has a thickness substantially equal to that of the negative electrode layer 140.

[0092] like Figure 2 and 3 As shown, the all-solid-state battery 100 may include a plurality of first edge layers 150' and a plurality of second edge layers 150'''.

[0093] In the plurality of first edge layers 150' and the plurality of second edge layers 150''', the first edge layer 150' and the second edge layer 150''' connected to the outside may have as follows Figure 2 The structure shown. (Refer to...) Figure 2 The cross-sectional structure of the first cover layer 160a and the second cover layer 160b may have, for example, an "L" shape.

[0094] In the all-solid-state battery 100 according to the embodiment, such as Figure 2 and 3 As shown, the first edge layer 150' and the second edge layer 150''' can be set in a zigzag (zigzag) pattern.

[0095] Although not in Figure 2 and 3 As shown, however, the all-solid-state battery 100 may optionally include a third edge layer 150'', which is disposed on the extended plane of the solid electrolyte layer 130 and has a structure that partially overlaps with the first edge layer 150' and the second edge layer 150''' (see Figure 130). Figure 4D ).

[0096] Compared to the total area of ​​the third edge layer 150'' and the solid electrolyte layer 130 (100%), the area of ​​the third edge layer 150'' can be in the range of about 3% to about 20%. If the area of ​​the third edge layer 150'' is within the above range, an all-solid-state battery that can effectively protect the internal cell cells from external influences and improve energy density and rate characteristics can be realized.

[0097] Figure 4E This is an exploded perspective view schematically illustrating the stacked structure of an all-solid-state battery. A solid electrolyte structure 300 is arranged between a positive electrode structure 200 and a negative electrode structure 400, and a first capping layer 160a and a second capping layer 160b are provided at both ends thereto, thereby manufacturing an all-solid-state battery.

[0098] The terminals of the positive current collector 123 and the negative current collector 143 may be exposed on opposite sides of the multilayer structure of the all-solid-state battery 100. The exposed terminals may be connected and coupled to external electrodes 112 and 114. The external electrode 112 connected to the exposed terminal of the positive current collector 123 may be used as the positive electrode. The external electrode 114 connected to the exposed terminal of the negative current collector 143 may be used as the negative electrode.

[0099] External electrodes 112 and 114 may include conductive metal and glass.

[0100] The conductive metal may include, for example, copper (Cu), nickel (Ni), tin (Sn), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), tungsten (W), titanium (Ti), lead (Pb), or alloys thereof.

[0101] The glass may include, for example, silicon oxide, boron oxide, aluminum oxide, transition metal oxides, alkali metal oxides, alkaline earth metal oxides, or combinations thereof. The transition metals included in the glass may be selected from zinc (Zn), titanium (Ti), copper (Cu), vanadium (V), manganese (Mn), iron (Fe), or nickel (Ni); the alkali metals may be selected from lithium (Li), sodium (Na), or potassium (K); and the alkaline earth metals may be selected from magnesium (Mg), calcium (Ca), strontium (Sr), or barium (Ba).

[0102] The positive electrode layer 120 may include a positive electrode active material. For example, the positive electrode layer 120 may include a positive electrode current collector 123 and a positive electrode active material layer 121 or 122 disposed on one or the opposite side of the positive electrode current collector 123.

[0103] Any positive electrode active material can be used without limitation, provided that the positive electrode active material is generally applicable in all-solid-state batteries. As a positive electrode active material, compounds capable of reversibly inserting and de-intercalating lithium (lithiation intercalation compounds) can be used. Specifically, a composite oxide of lithium and at least one metal selected from cobalt, manganese, nickel, and combinations thereof can be used. The composite oxide can be a lithium transition metal composite oxide, and specific examples may include lithium nickel-based oxides, lithium cobalt-based oxides, lithium manganese-based oxides, lithium iron phosphate-based compounds, cobalt-free lithium nickel manganese-based oxides, or combinations thereof. As an example, a compound represented by any of the following formula can be used: Li a A 1-b X b O 2-c D c Where 0.90≤a≤1.8, 0≤b≤0.5, and 0≤c≤0.05; Li a Mn 2-b X b O 4-c D c Where 0.90≤a≤1.8, 0≤b≤0.5, and 0≤c≤0.05; Li a Ni 1-b-c Co b X c O 2-α D α Where 0.90≤a≤1.8, 0≤b≤0.5, and 0≤c≤0.5, 0<α<2; Li a Ni 1-b-c Mn b X c O 2-αD α Where 0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, and 0<α<2; Li a Ni b Co c L 1 d G e O2, where 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0 ≤ d ≤ 0.5, and 0 ≤ e ≤ 0.1; Li a NiG b O2, where 0.90 ≤ a ≤ 1.8 and 0.001 ≤ b ≤ 0.1; Li a CoG b O2, where 0.90 ≤ a ≤ 1.8 and 0.001 ≤ b ≤ 0.1; Li a Mn 1-b G b O2, where 0.90 ≤ a ≤ 1.8 and 0.001 ≤ b ≤ 0.1; Li a Mn2G b O4, where 0.90 ≤ a ≤ 1.8 and 0.001 ≤ b ≤ 0.1; Li a Mn 1-g G g PO4, where 0.90 ≤ a ≤ 1.8 and 0 ≤ g ≤ 0.5; Li (3-f) Fe2(PO4)3, where 0 ≤ f ≤ 2; and Li a FePO4, where 0.90≤a≤1.8.

[0104] In the above formula, A can be Ni, Co, Mn, or a combination thereof; X can be Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements, or a combination thereof; D can be O, F, S, P, or a combination thereof; G can be Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; and L 1 It can be Mn, Al, or a combination thereof.

[0105] The positive electrode active material layer 121 or 122 may additionally include an adhesive, a conductive material, or a combination thereof. Representative examples of the adhesive may include polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers including ethylene oxide (including polymers containing ethylene oxide), polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, epoxy resin, (meth)acrylate resin, polyester resin, nylon, etc., but one or more embodiments are not limited thereto.

[0106] The conductive material may include, for example, a carbon-based conductive material. The carbon-based conductive material may include, for example, carbon black (CB), carbon fiber, graphite, fluorinated carbon, or a combination thereof. CB may be, for example, acetylene black (AB), Ketjen black (KB), super P (superconducting acetylene black), channel black, furnace black (FB), lamp black, thermal black, or a combination thereof. Graphite may be natural graphite or artificial graphite. In addition to the above-mentioned carbon-based conductive materials, the positive electrode active material layers 121 and 122 may further include a metal-based conductive material, a metal oxide-based conductive material, or a polymer-based conductive material. The metal-based conductive material, metal oxide-based conductive material, or polymer-based conductive material may be, for example, metal fibers; metal powders such as aluminum powder or nickel powder; conductive metal oxides such as zinc oxide or potassium titanate; or polyethylene derivatives.

[0107] The negative electrode active material layers 141 and 142 may include a negative electrode active material. The negative electrode active material may include at least one of the following: lithium metal phosphate, lithium metal oxide, metal oxide, or carbon-based negative electrode active material.

[0108] The carbon-based negative electrode active material may include, for example, amorphous carbon, crystalline carbon, porous carbon, or combinations thereof. Crystalline carbon may include, for example, graphite, such as unshaped, plate-like, flake-like, spherical, or fibrous natural or artificial graphite.

[0109] Amorphous carbon can include, for example, CB, AB, FB, KB, graphene, soft or hard carbon, mesophase pitch carbides, calcined coke, etc. Amorphous carbon can be non-crystalline or have very low crystallinity and be distinct from crystalline carbon.

[0110] The carbonaceous anode active material can be, for example, porous carbon. The pore volume of porous carbon can be, for example, about 0.1 cm³. 3 / g - approximately 10.0 cm 3 / g, approximately 0.5 cm 3 / g - approximately 5 cm 3 / g, or approximately 0.1 cm 3 / g - approximately 1 cm 3 The average pore size of porous carbon can be, for example, in the range of about 1 nm to about 50 nm, about 1 nm to about 30 nm, or about 1 nm to about 10 nm. The Brunauer-Emmett-Teller (BET) specific surface area of ​​porous carbon can be, for example, about 100 m² / g. 2 / g - approximately 3,000m 2 Within the range of / g.

[0111] The negative electrode active material may be, for example, a compound selected from the following: Li 4 / 3 Ti5 / 3 O4, LiTiO2, LiM1 s M2 t O u (where M1 and M2 are transition metals, and s, t, and u are any positive numbers), TiO x (where 0 < x ≤ 3), and Li x V2(PO4)3 (where 0 < x ≤ 5). The negative electrode active material according to the embodiment may include Li 4 / 3 Ti 5 / 3 O4, LiTiO2, or a combination thereof.

[0112] The negative electrode active material layers 141 and 142 may contain a conductive material, a binder, or a combination thereof. The conductive material and the binder of the negative electrode active material layers 141 and 142 may be the same as those of the positive electrode active material layers 121 and 122.

[0113] The positive electrode current collector 123 and the negative electrode current collector 143 may be composed of, for example, a metal, a conductive oxide, or a combination thereof selected from copper, aluminum, nickel, silver, gold, platinum, and their alloys.

[0114] The solid electrolyte layer 130 may include an oxide-based solid electrolyte (oxide-based solid electrolyte).

[0115] The oxide-based solid electrolyte may be, for example, a garnet-type solid electrolyte. The solid electrolyte may be prepared, for example, by sintering or the like.

[0116] Materials having a garnet-phase crystal structure (cubic phase) may include, for example, compounds represented by Formula 3.

[0117] Formula 3

[0118] (Li x A a )(La y B b )(Zr z C c )O 12

[0119] In Formula 3, A may be a monovalent, divalent, or trivalent cation, or a combination thereof, B may be a monovalent, divalent, or trivalent cation, or a combination thereof, C may be a monovalent, divalent, trivalent, tetravalent, pentavalent, or hexavalent cation, or a combination thereof, 6 ≤ x ≤ 8, 0 ≤ a ≤ 2, 2 ≤ y ≤ 3, 0 ≤ b ≤ 1, 0 < z ≤ 2, and 0 ≤ c ≤ 2.

[0120] In Formula 3, the monovalent cations in A, B, and C may include at least one of Li, Na, or K. The divalent to hexavalent cations may include at least one of, for example, the following: Mg, Ca, Sr, Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Zr, Hf, V, Nb, Ta, Mo, W, Mn, Tc, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, Hg, Al, Ga, In, Tl, Ge, Sn, Pb, Sb, Bi, Po, As, Se, and Te.

[0121] In Formula 3, 6.1 ≤ x ≤ 8, 6.3 ≤ x ≤ 8, 6.5 ≤ x ≤ 8, or 6.7 ≤ x ≤ 8, and 0 ≤ a ≤ 2, 0.5 ≤ a ≤ 1.8, 0.7 ≤ a ≤ 1.8, or 1 ≤ a ≤ 2.

[0122] In Formula 3, 2 ≤ y ≤ 3, 2.3 ≤ y ≤ 3, 2.5 ≤ y ≤ 3, or 2.7 ≤ y ≤ 3, and 0 ≤ b ≤ 1, 0.3 ≤ b ≤ 1, 0.5 ≤ b ≤ 1, or 0.7 ≤ b ≤ 1.

[0123] In Formula 3, 0 < z ≤ 2, 0.3 ≤ z ≤ 2, 0.5 ≤ z ≤ 2, or 0.7 ≤ z ≤ 2, and 0 ≤ c ≤ 2, 0 ≤ c ≤ 0.7, 0 ≤ c ≤ 0.5, or 0 ≤ c ≤ 0.3.

[0124] The compound of Formula 3 may contain a compound represented by Formula 4.

[0125] Formula 4

[0126] (Li x )(La y B b )(Zr z C c )O 12

[0127] In Formula 4, B may be at least one of the following: calcium (Ca), strontium (Sr), cesium (Cs), or barium (Ba), C may be at least one of the following: aluminum (Al), tungsten (W), niobium (Nb), or tantalum (Ta), 6 ≤ x ≤ 8, 2 ≤ y ≤ 3, 0 < z ≤ 2, 0 < b ≤ 1, and 0.01 ≤ c ≤ 2.

[0128] The electrolyte having a garnet phase crystal structure (cubic phase) according to an embodiment may include, for example, Li7La3Zr2O 12 (LLZO), Li 6.5 La3Zr 1.5 Ta 0.5 O 12 、Li6.5 La3Zr 1.5 Nb 0.5 O 12 Li 6.25 La3Zr2Al 0.25 O 12 wait.

[0129] According to another embodiment, the electrolyte having a garnet phase crystal structure (cubic phase) may include Li x La3M2O 12 (where 6≤x≤8, and M=Ta, Nb, or Zr), Li x La3Zr 2-α M α O 12 (where 6≤x≤8, and M=Ta or Nb), Li6. 24 La3Zr2Al 0.24 O 12 、Li7La3Zr 1.7 W 0.3 O 12 Li 4.9 La 2.5 Ca 0.5 Zr 1.7 Nb 0.3 O 12 Li 6.4 La3Zr 1.7 W 0.3 O 12 、Li7La3Zr 1.5 W 0.5 O 12 、Li7La3Zr 1.5 Nb 0.5 O 12 、Li7La3Zr 1.5 Ta 0.5 O 12 、Li7La 2.75 Ca 0.25 Zr 1.75 Nb 0.25 O 12 Li 6.272 La3Zr 1.7 W 0.3 O 12 wait.

[0130] In addition to the oxide-based solid electrolyte, the solid electrolyte layer 130 may further include an amorphous electrolyte. The amorphous material may be flexible to connect or fill pores of the oxide-based solid electrolyte particles. By having such a structure, oxides with excellent density can be prepared.

[0131] Amorphous electrolytes may include glass-based materials exhibiting a glass transition. For example, amorphous electrolytes may include at least one of lithium (Li), oxygen (O), and germanium (Ge), silicon (Si), boron (B), and phosphorus (P), and specifically, amorphous electrolytes may be glasses comprising at least one of Li₂O, GeO₂, SiO₂, B₂O₃, and P₂O₅. For example, amorphous electrolytes may include Li, B, Si, and O, and may be glasses comprising, for example, SiO₂, B₂O₃, and Li₂O. Here, glass refers to a material that is crystallographically amorphous in X-ray diffraction or electron diffraction.

[0132] When the amorphous electrolyte includes Li₂O, the Li₂O content can range from about 20 mol% to about 75 mol%, about 25 mol% to about 75 mol%, about 30 mol% to about 75 mol%, about 40 mol% to about 75 mol%, or about 50 mol% to about 75 mol%. When the amorphous electrolyte includes SiO₂, the SiO₂ content can range from more than about 0 mol% to about 70 mol%, about 5 mol% to about 50 mol%, or about 10 mol% to about 30 mol%. If the amorphous electrolyte includes B₂O₃, the B₂O₃ content can range from more than 0 mol% to about 80 mol%, about 5 mol% to about 80 mol%, about 10 mol% to about 60 mol%, or about 20 mol% to about 50 mol%. Furthermore, the content of each oxide in the amorphous electrolyte can be the content of each oxide relative to the total content of the corresponding oxide, and specifically, the ratio of the content (moles) of each oxide to at least one of SiO₂, B₂O₃, and P₂O₅ and the total amount (moles) of Li₂O can be a percentage (moles%). The content of each oxide can be measured using inductively coupled plasma atomic emission spectrometry (ICP-AES).

[0133] Amorphous oxides may further include additive elements as needed. Examples of additive elements may include at least one of sodium (Na), magnesium (Mg), aluminum (Al), potassium (K), calcium (Ca), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), gallium (Ga), selenium (Se), rubidium (Rb), sulfur (S), yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), silver (Ag), indium (In), tin (Sn), antimony (Sb), cesium (Cs), barium (Ba), hafnium (Hf), tantalum (Ta), tungsten (W), lead (Pb), bismuth (Bi), gold (Au), lanthanum (La), neodymium (Nd), or europium (Eu). Oxide glass materials may include at least one of these additive elements as oxides.

[0134] Solid electrolytes may include Li, La, Zr, Ta, O, B, and Si. B and / or Si may be obtained from oxides.

[0135] Solid electrolytes may include oxides containing lanthanum, zirconium, tantalum, lithium, boron, and silicon, and may include a lanthanum weight ratio of G to lithium. La / G Li Oxides in the range of approximately 6 to approximately 15. Specifically, in solid electrolytes, the weight ratio of lanthanum to lithium is G. La / G Li The content can range from about 6.0 to about 10.0, about 7.0 to about 10.0, or about 8.0 to about 10.0. For example, the lanthanum content can range from about 40 parts by weight to about 60 parts by weight, and the lithium content can range from about 1 part by weight to about 8 parts by weight. The contents of lanthanum and lithium, as well as the weight ratio of lanthanum to lithium, can be evaluated by inductively coupled plasma (ICP) analysis.

[0136] The solid electrolyte layer 130 may further include a binder. The binder may be selected from the binders used in the positive electrode active material layers 121 and 122. The amount of binder used in the solid electrolyte layer 130 may be selected from the amount of binder used in the positive electrode active material layers 121 and 122. The binder may be removed by partial or complete evaporation and / or carbonization during the sintering process of the solid electrolyte layer 130. The binder may be omitted.

[0137] At least one of the first capping layer, the second capping layer, the first edge layer 150', and the second edge layer 150''' may contain an oxide comprising pyrochlore crystalline material. Additionally, the third edge layer 150'' may contain an oxide comprising pyrochlore crystalline material.

[0138] The edge layer and capping layer should have extremely low ionic and electronic conductivity to minimize self-discharge during storage and should exhibit high stability to the external environment. Additionally, the edge layer and / or capping layer should have high compatibility during battery manufacturing. Specifically, an MLC battery can be formed by simultaneously sintering a first capping layer, a positive electrode, a first edge layer, an electrolyte, a third edge layer, a negative electrode, a second edge layer, and a second capping layer. Therefore, in the battery manufacturing environment, the edge layer and / or capping layer can exhibit behavior similar to other battery components (such as solid electrolytes). For example, the edge layer and / or capping layer can be sintered and formed at the same temperature and pressure as the solid electrolyte. If the edge layer and / or capping layer do not form with sufficient density, low ionic conductivity, etc., at the temperature and pressure required for solid electrolyte formation, high battery performance (stability, etc.) is difficult to expect.

[0139] Pyrochlore crystalline materials can be sintered and formed at the same temperature and pressure as garnet crystalline materials. For example, pyrochlore and garnet crystalline materials can be formed by heat-treating the corresponding raw materials at a temperature of about 200°C to about 700°C and a pressure of about 5 MPa to about 300 MPa. Therefore, the edge layer and / or capping layer according to the embodiments can have excellent compatibility in the battery manufacturing process using garnet-type solid electrolytes.

[0140] Pyrochlore crystalline materials can have a higher density than sintered garnet crystalline materials and can be formed under similar or identical temperatures and pressures. Therefore, the edge layer and / or capping layer according to the embodiments can have high stability against solvents and binders during the battery manufacturing process. Additionally, the edge layer and / or capping layer according to the embodiments can effectively protect the internal cell units from external environmental influences such as moisture. In particular, the edge layer and / or capping layer according to the embodiments can increase the stability of batteries comprising garnet-type solid electrolytes.

[0141] The edge layer and / or cover layer according to the embodiments may have a density of 90% or higher, about 93% to about 99.5%, about 93.5% to about 99%, or about 93.7% to about 97.2%. In this specification, the term "density" refers to the density calculated by measuring the dimensions (diameter and thickness) and mass of the sintered body. Density may be a relative density. Density can be determined as the ratio of the measured density of the sintered body to its theoretical density. The measured density can be obtained using a densitometer (e.g., a specific gravity bottle) based on Archimedes' principle, and the theoretical density of the sintered body can be calculated using the theoretical density of the constituent raw materials or substances.

[0142] The pyrochlore crystalline material can have sufficiently low ionic conductivity and sufficiently low electronic conductivity. The edge layer and / or capping layer according to the embodiment can have a conductivity of 1.0 × 10⁻⁶. -8 S / cm or less, or approximately 1.0 × 10 -10 S / cm to approximately 1.0 × 10 -8 Ionic conductivity in S / cm.

[0143] Pyrochlore crystalline materials can have lower ionic conductivity than garnet crystalline materials. Therefore, the edge layer and / or capping layer according to embodiments can have lower ionic conductivity than the solid electrolyte. In the all-solid-state battery 100 according to embodiments, the ionic conductivity of the solid electrolyte can be 100 times or greater than that of the edge layer and / or capping layer, for example, about 100 to about 1,000 times. The edge layer and capping layer according to embodiments can substantially prevent self-discharge of the battery including the garnet-type solid electrolyte.

[0144] The edge layer and / or cover layer according to the embodiment may have a size of less than 1.0 × 10⁻⁶.-7 S / cm, 1.0×10 -8 S / cm or less, or approximately 1.0 × 10 -9 S / cm to approximately 1.0 × 10 -8 Electron conductivity in S / cm.

[0145] The pyrochlore crystal material can be a lithium-free material and may contain a compound represented by Formula 1.

[0146] Formula 1

[0147] (La 1-a B a ) 2+nx Zr 2-(n+1)x C x O7

[0148] In Equation 1, B can be one or more trivalent cations, C can be one or more tetravalent cations, one or more pentavalent cations, or one or more hexavalent cations, 0≤a<1, and 0≤x<0.66.

[0149] n = (oxidation number of C) - (oxidation number of Zr).

[0150] In Equation 1, the oxidation number of Zr can be, for example, 4.

[0151] In Formula 1, B can be at least one of scandium (Sc), yttrium (Y), aluminum (Al), gallium (Ga), or indium (In).

[0152] In Formula 1, C can be at least one of tungsten (W), niobium (Nb), bismuth (Bi), antimony (Sb), or tantalum (Ta).

[0153] In formulas B and C, the trivalent to hexavalent cations may include at least one of, for example, Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Zr, Hf, V, Nb, Ta, Mo, W, Mn, Tc, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Ag, Au, Cd, Al, Ga, In, Tl, Ge, Sn, Pb, Sb, Bi, Po, As, S, and Te.

[0154] In Equation 1, 0 ≤ a < 1, 0 ≤ a < 0.8, 0 ≤ a < 0.5, or 0 ≤ a < 0.3.

[0155] In Equation 1, 0 ≤ x < 0.66, 0 ≤ x < 0.5, or 0 ≤ x < 0.4.

[0156] Pyrochlore crystal materials may contain compounds represented by Formula 2.

[0157] Formula 2

[0158] La 2+x Zr 2-2x Ta x O7

[0159] In Equation 2, 0 ≤ x < 0.66.

[0160] For example, in Equation 2, 0 ≤ x < 0.5 or 0 ≤ x < 0.4.

[0161] Pyrochlore crystalline materials can be lithium-free phases, such as La. 2+x Zr 2-2x Ta x O7, where 0 ≤ x < 0.66.

[0162] According to the embodiments, the edge layer and / or capping layer may exhibit peaks in X-ray diffraction (XRD) spectra at diffraction angles of about 2θ at about 27.5° to about 29°, about 32° to about 33.5°, about 46.5° to about 48°, and about 55° to about 56.5°. These peaks may correspond to pyrochlore phase crystalline materials.

[0163] In addition to the pyrochlore crystalline material, the edge layer and / or capping layer according to the embodiments may further comprise an amorphous oxide. The amorphous material may be flexible to connect or fill pores of the pyrochlore crystalline material particles. By having such a structure, an oxide with excellent density can be prepared.

[0164] Amorphous oxides may include glass-based materials exhibiting a glass transition. For example, amorphous oxides may include at least one of lithium (Li), oxygen (O), and germanium (Ge), silicon (Si), boron (B), and phosphorus (P), and specifically, amorphous oxides may be glasses comprising at least one of Li₂O, GeO₂, SiO₂, B₂O₃, or P₂O₅. For example, amorphous oxides may include Li, B, Si, and O, and may be glasses comprising, for example, SiO₂, B₂O₃, and Li₂O. Here, glass refers to a material that is crystallographically amorphous in X-ray diffraction or electron diffraction.

[0165] If the amorphous oxide includes Li₂O, the content of Li₂O may be in the range of about 20 mol% to about 75 mol%, about 25 mol% to about 75 mol%, about 30 mol% to about 75 mol%, about 40 mol% to about 75 mol%, or about 50 mol% to about 75 mol%. If the amorphous oxide includes SiO₂, the content of SiO₂ may be in the range of greater than 0 mol% to about 70 mol%, about 5 mol% to about 50 mol%, or about 10 mol% to about 30 mol%. If the amorphous oxide includes B₂O₃, the content of B₂O₃ may be in the range of greater than 0 mol% to about 80 mol%, about 5 mol% to about 80 mol%, about 10 mol% to about 60 mol%, or about 20 mol% to about 50 mol%. Furthermore, the content of each oxide in the amorphous oxide may be the content of each oxide relative to the total content of the corresponding oxide, and specifically, the ratio of the content (moles) of each oxide to at least one of SiO₂, B₂O₃, or P₂O₅ and the total amount (moles) of Li₂O may be a percentage (moles%). The content of each oxide can be measured using ICP-AES.

[0166] Amorphous oxides may further include additive elements as needed. Examples of additive elements may include at least one of sodium (Na), magnesium (Mg), aluminum (Al), potassium (K), calcium (Ca), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), gallium (Ga), selenium (Se), rubidium (Rb), sulfur (S), yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), silver (Ag), indium (In), tin (Sn), antimony (Sb), cesium (Cs), barium (Ba), hafnium (Hf), tantalum (Ta), tungsten (W), lead (Pb), bismuth (Bi), gold (Au), lanthanum (La), neodymium (Nd), or europium (Eu). Oxide glass-based materials may include at least one of these additive elements as oxides.

[0167] The edge layer and / or capping layer may comprise materials containing Li, La, Zr, Ta, and O, or may comprise Li, La, Zr, Ta, O, B, and Si. Lithium may be derived from amorphous oxides.

[0168] The edge layer and / or capping layer may comprise an oxide containing lanthanum, zirconium, tantalum, lithium, boron, and silicon, wherein the lanthanum content ranges from about 25 parts by weight to about 40 parts by weight, the lithium content ranges from about 6 parts by weight to about 10 parts by weight, the zirconium content ranges from about 8 parts by weight to about 15 parts by weight, the tantalum content ranges from about 5 parts by weight to about 8 parts by weight, the boron content ranges from about 4 parts by weight to about 6 parts by weight, and the silicon content ranges from about 1 part by weight to about 3 parts by weight. The weight ratio of each component constituting the oxide can be evaluated by ICP analysis.

[0169] The edge layer and / or capping layer may include a lanthanum to lithium weight ratio G La / G Li Oxides ranging from about 3 to about 5 parts by weight. For example, the content of lanthanum may range from about 25 parts by weight to about 40 parts by weight, and the content of lithium may range from about 6 parts by weight to about 10 parts by weight. Specifically, the weight ratio of lanthanum to lithium is G. La / G Li It can range from about 3.05 to about 4.99, from about 3.1 to about 4.99, or from about 3.14 to about 4.96. The contents of lanthanum and lithium, as well as the weight ratio of lanthanum to lithium, can be evaluated by ICP analysis.

[0170] The weight ratio of lanthanum to lithium in the edge layer and / or capping layer (G) La / G Li It can be less than the weight ratio G of solid electrolytes La / G Li .

[0171] The pyrochlore phase content, relative to 100 parts by weight of the total oxide content in the edge layer and / or capping layer, can range from about 90 parts by weight to about 99.5 parts by weight, about 95 parts by weight to about 99 parts by weight, or about 97 parts by weight to about 99 parts by weight. The amorphous material content, relative to 100 parts by weight of the total oxide content in the edge layer and / or capping layer, can range from about 0.5% by weight to about 10% by weight, about 1% by weight to about 5% by weight, or about 1% by weight to about 3% by weight. The content or mixing ratio of the pyrochlore phase in the oxides used in the edge layer and / or capping layer can be confirmed by XRD analysis or transmission electron microscopy / selected area electron diffraction (TEM / SAED). XRD analysis allows selection of the predominantly retained crystalline phases, and XRD Rietveld analysis can be performed to determine the mixing ratio of each crystalline phase.

[0172] The method for manufacturing an all-solid-state battery according to the embodiment is as follows. The method for manufacturing the MLC cell in the all-solid-state battery is as follows.

[0173] The method may include:

[0174] A positive electrode structure is prepared such that the formed positive electrode structure has a first edge layer that does not overlap with the positive electrode layer;

[0175] A negative electrode structure is prepared such that the formed negative electrode structure has a second edge layer that does not overlap with the negative electrode layer to form a composition;

[0176] A multilayer structure is formed, such that the solid electrolyte forming composition is disposed between the positive electrode structure and the negative electrode structure;

[0177] A first capping layer composition is provided on the first outermost layer of the multilayer structure; and

[0178] A second cover layer is provided on the second outermost layer of the multilayer structure to form a composition to provide a stack, the second outermost layer being disposed on the side opposite to the first outermost layer of the multilayer structure.

[0179] The solid electrolyte forming composition can be applied and dried to form a film. For example, the solid electrolyte forming composition can be applied to a substrate and dried to prepare a solid electrolyte precursor film.

[0180] The positive electrode structure and / or the negative electrode structure can be prepared on the solid electrolyte precursor membrane. Specifically, the multilayer structure can be prepared by the following:

[0181] A positive electrode structure is prepared to be formed on the first solid electrolyte precursor film, such that the first edge layer forming composition does not overlap with the positive electrode forming composition;

[0182] A negative electrode structure is prepared to be formed on the second solid electrolyte precursor film, such that the second edge layer forming composition does not overlap with the negative electrode forming composition; and

[0183] The first solid electrolyte precursor membrane or the second solid electrolyte precursor membrane is inserted between the positive electrode structure and the negative electrode structure.

[0184] The solid electrolyte forming composition may be provided only on a portion of the substrate. For example, the first solid electrolyte precursor membrane and / or the second solid electrolyte precursor membrane may further include a third edge layer forming composition in areas where the solid electrolyte forming composition is not provided (is not present). The third edge layer forming composition may be provided to partially overlap with the first edge layer forming composition and / or the second edge layer forming composition in the stack, as described below.

[0185] If the solid electrolyte precursor membrane has a self-supporting (self-standing) state, the substrate can be omitted.

[0186] The positive electrode structure may be formed on one side of the first solid electrolyte precursor membrane. The positive electrode structure may include the positive electrode forming composition and the first edge layer forming composition.

[0187] The positive electrode forming composition may be provided only on a portion of one side of the first solid electrolyte precursor membrane. For example, the positive electrode forming composition may be provided as a first edge extending to the first solid electrolyte precursor membrane.

[0188] The positive electrode forming composition may be provided on one side of the first solid electrolyte precursor membrane, i.e., applied once, twice, or more. For example, the positive electrode forming composition may be provided once on the first solid electrolyte precursor membrane. Alternatively, after the positive electrode forming composition is provided once on the first solid electrolyte precursor membrane, a positive electrode current collector composition (positive electrode current collector component) may be provided thereon, and the positive electrode forming composition may be provided again on the positive electrode current collector composition. In this case, the positive electrode structure may have the form in which the substrate, the first solid electrolyte precursor membrane, the positive electrode forming composition, the positive electrode current collector composition, and the positive electrode forming composition are sequentially stacked.

[0189] The first edge layer forming composition may be provided on one side of the first solid electrolyte precursor membrane on which the positive electrode forming composition is provided. The first edge layer forming composition may be provided only on a portion of one side of the first solid electrolyte precursor membrane and may be provided such that it substantially does not overlap with the positive electrode forming composition. The first edge layer forming composition may be provided with a thickness substantially equal to the thickness of the positive electrode forming composition. For example, the first edge layer forming composition may be provided with a thickness equal to the sum of the thicknesses of the positive electrode forming composition, the positive current collector composition, and the positive electrode forming composition.

[0190] The negative electrode structure may be formed separately on one side of the second solid electrolyte precursor membrane. The negative electrode structure may include the negative electrode forming composition and the second edge layer forming composition.

[0191] The negative electrode forming composition may be provided only on a portion of the second solid electrolyte precursor membrane. For example, the negative electrode forming composition may be provided as a second edge extending to the second solid electrolyte precursor membrane.

[0192] The negative electrode forming composition may be provided on one side of the second solid electrolyte precursor membrane, i.e., applied once, twice, or more. For example, the negative electrode forming composition may be provided once on the second solid electrolyte precursor membrane. Alternatively, after the negative electrode forming composition is provided once on the second solid electrolyte precursor membrane, a negative electrode current collector composition (negative electrode current collector component) may be provided thereon, and the negative electrode forming composition may be provided again on the negative electrode current collector composition. In this case, the negative electrode structure may have the form in which the substrate, the second solid electrolyte precursor membrane, the negative electrode forming composition, the negative electrode current collector composition, and the negative electrode forming composition are sequentially stacked.

[0193] The second edge layer forming composition may be provided on one side of the second solid electrolyte precursor membrane on which the negative electrode forming composition is provided. The second edge layer forming composition may be provided only on a portion of one side of the second solid electrolyte precursor membrane and may be provided so as not to substantially overlap with the negative electrode forming composition. The second edge layer forming composition may be provided to have a thickness substantially equal to the thickness of the negative electrode forming composition. For example, the second edge layer forming composition may be provided to have a thickness equal to the sum of the thicknesses of the negative electrode forming composition, the negative electrode current collector composition, and the negative electrode forming composition.

[0194] The substrate can be separated and removed from the stack of the substrate, the first solid electrolyte precursor film, and the positive electrode structure. The substrate can also be separated and removed from the stack of the substrate, the second solid electrolyte precursor film, and the negative electrode structure.

[0195] The first solid electrolyte precursor membrane or the second solid electrolyte precursor membrane may be stacked to be disposed between the positive electrode structure and the negative electrode structure, thereby forming a multilayer structure. For example, the multilayer structure may include a structure comprising the negative electrode structure, the first solid electrolyte precursor membrane, and the positive electrode structure.

[0196] The stack can be prepared by providing a first capping layer forming composition on a first outermost layer of a multilayer structure, and providing a second capping layer forming composition on a second outermost layer of a multilayer structure disposed on the opposite side of the first outermost layer of the multilayer structure. The stack may have a structure comprising the first capping layer forming composition, the positive electrode structure, the solid electrolyte forming composition, and the negative electrode structure. The process can be repeated once or multiple times to form a stack with a multilayer structure. For example, the positive electrode structure, the solid electrolyte forming composition, the negative electrode structure can be repeated, and the process can end with the second capping layer forming composition.

[0197] Optionally, the stack can be pressed before or after heat treatment. Alternatively, the stack can be cut before or after heat treatment. Here, the cutting dimensions can vary depending on the capacity of the MLC cell, and for example, the stack can be cut to a width of about 5 mm to about 15 mm (e.g., 10 mm) and a length of about 5 mm to about 15 mm (e.g., 10 mm). Such a cutting process can be omitted.

[0198] External electrodes 112 and 114 can be formed on the stack obtained by such a process, thereby manufacturing an MLC cell according to an embodiment.

[0199] The external electrodes 112 and 114 can be formed, for example, by dipping the stack into a conductive paste including a conductive metal and glass. The external electrodes 112 and 114 can be formed, for example, by printing a conductive paste on the surface of the stack by a screen printing method or a gravure printing method. The external electrodes 111 and 114 can be formed, for example, by applying a conductive paste on the surface of the stack or transferring a dry film of the conductive paste to the stack.

[0200] The solid electrolyte forming composition may include elements capable of forming a garnet-type material and their contents. Specifically, the solid electrolyte forming composition may include a garnet-type solid electrolyte of Formula 3, or may include appropriate contents of elements for forming a garnet-type solid electrolyte of Formula 3 (garnet-type solid electrolyte precursor).

[0201] Formula 3

[0202] (Li x A a )(La y B b )(Zr z C c )O 12

[0203] In Formula 3,

[0204] A can be a monovalent, divalent, or trivalent cation, or a combination thereof,

[0205] B can be a monovalent, divalent, or trivalent cation, or a combination thereof,

[0206] C can be a monovalent, divalent, trivalent, tetravalent, pentavalent, or hexavalent cation, or a combination thereof, 6 ≤ x ≤ 8, 0 ≤ a ≤ 2, 2 ≤ y ≤ 3, 0 ≤ b ≤ 1, 0 < z ≤ 2, and 0 ≤ c ≤ 2.

[0207] For example, a can be 0, b can be 0, and C can be tantalum.

[0208] The solid electrolyte forming composition can be prepared as follows: mixing a lithium precursor, a lanthanum precursor, a zirconium precursor, and a precursor containing an element C in a ratio allowing for the formation of a garnet-type electrolyte, and subjecting the mixture to mechanochemical synthesis.

[0209] The lithium precursor, the lanthanum precursor, the zirconium precursor, and the carbon-containing precursor may each comprise an oxide, sulfate, chloride, or combination thereof containing lithium, lanthanum, zirconium, and carbon. The lithium precursor may include, for example, Li₂O, LiCl, LiOH, Li₂(CO₃), etc. The lanthanum precursor may include, for example, La₂O₃, LaCl₃, etc., and the zirconium precursor may include, for example, ZrO₂, ZrCl₂, etc. The carbon-containing precursor may be a tantalum precursor, and the tantalum precursor may include, for example, Ta₂O₅, TaCl₅, etc.

[0210] The solid electrolyte forming composition may further include materials for forming amorphous electrolytes.

[0211] Amorphous electrolytes may include Li, B, Si, and O, and may be, for example, glasses including SiO2, B2O3, and Li2O. Here, glass refers to a material that is crystallographically amorphous in X-ray diffraction or electron diffraction.

[0212] If the amorphous electrolyte includes Li₂O, the Li₂O content may range from about 20 mol% to about 75 mol%, from about 25 mol% to about 75 mol%, from about 30 mol% to about 75 mol%, from about 40 mol% to about 75 mol%, or from about 50 mol% to about 75 mol%. If the amorphous electrolyte includes SiO₂, the SiO₂ content may range from greater than 0 mol% to about 70 mol%, from about 5 mol% to about 50 mol%, or from about 10 mol% to about 30 mol%. If the amorphous electrolyte includes B₂O₃, the B₂O₃ content may range from greater than 0 mol% to about 80 mol%, from about 5 mol% to about 80 mol%, from about 10 mol% to about 60 mol%, or from about 20 mol% to about 50 mol%. Furthermore, the content of each oxide in the amorphous electrolyte may be the content of each oxide relative to the total content of the corresponding oxide, and specifically, the ratio of the content (moles) of each oxide to at least one of SiO₂, B₂O₃, and P₂O₅ and the total amount (moles) of Li₂O may be a percentage (moles%).

[0213] Specifically, the solid electrolyte forming composition may include materials for forming a garnet-type solid electrolyte and materials for forming an amorphous electrolyte. The solid electrolyte forming composition may be in an amorphous phase. The solid electrolyte forming composition may include a La precursor (e.g., La₂O₃), a Li precursor (e.g., Li₂O), a Zr precursor (e.g., ZrO₂), a Ta precursor (e.g., Ta₂O₅), a Si precursor (e.g., SiO₂), and a B precursor (e.g., B₂O₃). The solid electrolyte forming composition may be prepared by mixing the La precursor (e.g., La₂O₃), Li precursor (e.g., Li₂O), Zr precursor (ZrO₂), Ta precursor (Ta₂O₅), Si precursor (SiO₂), and B precursor (B₂O₃) in a desired ratio, and then performing a mechanochemical synthesis on the mixture.

[0214] The solid electrolyte forming composition can be in a weight ratio of about 6 to about 15 G La / G Li It includes lanthanum and lithium. Specifically, in the solid electrolyte forming composition, the weight ratio of lanthanum to lithium is G. La / G Li The content can be in the range of about 6.0 to about 10.0, about 7.0 to about 10.0, or about 8.0 to about 10.0. For example, in the solid electrolyte forming composition, the lanthanum content can be in the range of about 40 parts by weight to about 60 parts by weight, and the lithium content can be in the range of about 1 part by weight to about 8 parts by weight. The content of lanthanum and lithium, as well as the weight ratio of lanthanum to lithium, can be evaluated by ICP analysis.

[0215] The solid electrolyte forming composition may further include a binder.

[0216] The solid electrolyte forming composition may further include sintering aids.

[0217] Mechanochemical synthesis processes may include mechanical grinding, etc. Mechanical grinding may include, for example, high-energy mechanical grinding (HEMM). HEMM refers to a process in which mechanical energy is applied to combine (bond) the components.

[0218] The positive electrode forming composition may contain a positive electrode active material, a binder, and a conductive material. The positive electrode forming composition may contain a positive electrode active material and a binder. As the positive electrode active material and the binder, positive electrode active materials and binders used in all-solid-state batteries can be used. As the positive electrode forming composition, materials known in the art can be used, such that the positive electrode active material and the binder have the above-described composition. The positive electrode forming composition may further include a solvent. The binder can improve the adhesion between the components of the positive electrode active material layers 121 and 122 and the adhesion of the positive electrode active material layers 121 and 122 to the positive electrode current collector 123. The binder content relative to 100 parts by weight of the positive electrode active material may range from about 1 part by weight to about 10 parts by weight or from about 2 parts by weight to about 7 parts by weight. The binder can be removed by partial or complete evaporation and / or carbonization during the sintering process of the positive electrode active material layers 121 and 122. The binder may be omitted.

[0219] The content of conductive material can range from about 1 part by weight to about 10 parts by weight or from about 2 parts by weight to about 7 parts by weight relative to 100 parts by weight of positive electrode active material. Conductive material may be omitted.

[0220] In the negative electrode forming composition, negative electrode active materials and binders used in all-solid-state batteries can be used as the negative electrode active material and binder. Materials known in the art can be used as the negative electrode forming composition, such that the negative electrode active material and the binder have the compositions described above. The conductive material and binder may be selected to be the same as those used in the positive electrode active material layers 121 and 122, respectively. The binder can be removed by partial or complete evaporation and / or carbonization during the sintering process of the negative electrode active material layers 141 and 142. The binder and conductive material may be omitted. The negative electrode forming composition may further include a solvent.

[0221] The positive current collector composition (positive current collector component) and the negative current collector composition (negative current collector component) may each contain a metal selected from copper, aluminum, nickel, silver, gold, and their alloys, a conductive oxide, or a combination thereof. As a specific example, aluminum can be used as the positive current collector, and copper can be used as the negative current collector.

[0222] At least one of the first edge layer forming composition, the second edge layer forming composition, the third edge layer forming composition, the first cover layer forming composition, and the second cover layer forming composition may include a material that gives the composition a pyrochlore crystalline material after heat treatment.

[0223] Edge layer / cover layer forming composition

[0224] The edge layer / capping layer forming composition may include elements capable of forming pyrochlore crystals and their amounts. Specifically, the edge layer / capping layer forming composition may include pyrochlore crystals of Formula 1, or may include appropriate amounts of elements for forming pyrochlore crystals of Formula 1 (pyrochlore crystal precursors).

[0225] Formula 1

[0226] (La 1-a B a ) 2+nx Zr 2-(n+1)x C x O7

[0227] In Equation 1,

[0228] B can be one or more trivalent cations.

[0229] C can be one or more tetravalent cations, one or more pentavalent cations, or one or more hexavalent cations.

[0230] 0≤a<1, and 0≤x<0.66, and

[0231] n = (oxidation number of C) - (oxidation number of Zr).

[0232] In Equation 1, the oxidation number of Zr can be, for example, 4.

[0233] In Formula 1, B may be at least one of scandium (Sc), yttrium (Y), aluminum (Al), gallium (Ga), and indium (In), and C may be at least one of tungsten (W), niobium (Nb), bismuth (Bi), antimony (Sb), and tantalum (Ta).

[0234] In formulas B and C, the trivalent to hexavalent cations may include at least one of, for example, Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Zr, Hf, V, Nb, Ta, Mo, W, Mn, Tc, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Ag, Au, Cd, Al, Ga, In, Tl, Ge, Sn, Pb, Sb, Bi, Po, As, S, and Te.

[0235] In Equation 1, 0 ≤ a < 1, 0 ≤ a < 0.8, 0 ≤ a < 0.5, or 0 ≤ a < 0.3.

[0236] In Equation 1, 0 ≤ x < 0.66, 0 ≤ x < 0.5, or 0 ≤ x < 0.4.

[0237] Pyrochlore crystalline materials can be lithium-free phases, such as La. 2+x Zr2-2x Ta x O7, where 0 ≤ x < 0.66.

[0238] The edge layer / capping layer forming composition can be prepared by mixing a lithium precursor, a lanthanum precursor, a zirconium precursor, and a C-containing precursor (e.g., a tantalum precursor) in a ratio that allows for the formation of pyrochlore crystals, and then subjecting the mixture to mechanochemical synthesis.

[0239] The lanthanum precursor, the zirconium precursor, and the carbon-containing precursor (e.g., the tantalum precursor) may each comprise an oxide, sulfate, chloride, or combination thereof containing lanthanum, zirconium, and carbon. The lanthanum precursor may include, for example, La₂O₃, LaCl₃, etc., and the zirconium precursor may include, for example, ZrO₂, ZrCl₂, etc. The tantalum precursor may include, for example, Ta₂O₅, TaCl₅, etc.

[0240] The edge layer / capping layer forming composition may further include amorphous oxides.

[0241] Amorphous oxides may include Li, B, Si, and O, and may be, for example, glasses including SiO2, B2O3, and Li2O. Here, glass refers to a material that is crystallographically amorphous in X-ray diffraction or electron diffraction.

[0242] If the amorphous oxide includes Li₂O, the content of Li₂O may range from about 20 mol% to about 75 mol%, from about 25 mol% to about 75 mol%, from about 30 mol% to about 75 mol%, from about 40 mol% to about 75 mol%, or from about 50 mol% to about 75 mol%. If the amorphous oxide includes SiO₂, the content of SiO₂ may range from greater than 0 mol% to about 70 mol%, from about 5 mol% to about 50 mol%, or from about 10 mol% to about 30 mol%. If the amorphous oxide includes B₂O₃, the content of B₂O₃ may range from greater than 0 mol% to about 80 mol%, from about 5 mol% to about 80 mol%, from about 10 mol% to about 60 mol%, or from about 20 mol% to about 50 mol%. Furthermore, the content of each oxide in the amorphous oxide may be the content of each oxide relative to the total content of the corresponding oxide, and specifically, the ratio of the content (moles) of each oxide to at least one of SiO₂, B₂O₃, and P₂O₅ and the total amount (moles) of Li₂O may be a percentage (moles%).

[0243] Specifically, the edge layer / capping layer forming composition may include materials for forming pyrochlore crystals and materials for forming an amorphous phase. The edge layer / capping layer forming composition may be in an amorphous phase. The edge layer / capping layer forming composition may include a La precursor (e.g., La₂O₃), a Li precursor (e.g., Li₂O), a Zr precursor (e.g., ZrO₂), a Ta precursor (Ta₂O₅), a Si precursor (SiO₂), and a B precursor (B₂O₃). The edge layer / capping layer forming composition may be prepared by mixing the La precursor (e.g., La₂O₃), Li precursor (e.g., Li₂O), Zr precursor (ZrO₂), Ta precursor (Ta₂O₅), Si precursor (SiO₂), and B precursor (B₂O₃) in a desired ratio, and then performing a mechanochemical synthesis on the mixture.

[0244] The edge layer / capping layer forming composition may include lanthanum, zirconium, tantalum, lithium, boron, and silicon, wherein the lanthanum content ranges from about 25 parts by weight to about 40 parts by weight, the lithium content ranges from about 6 parts by weight to about 10 parts by weight, the zirconium content ranges from about 8 parts by weight to about 15 parts by weight, the tantalum content ranges from about 5 parts by weight to about 8 parts by weight, the boron content ranges from about 4 parts by weight to about 6 parts by weight, and the silicon content ranges from about 1 part by weight to about 3 parts by weight. The weight ratio of each component can be evaluated by ICP analysis.

[0245] In the edge layer / capping layer forming composition, the weight ratio of lanthanum to lithium G La / G Li It can be in the range of about 3 to about 5. For example, the lanthanum content can be in the range of about 25 parts by weight to about 40 parts by weight, and the lithium content can be in the range of about 6 parts by weight to about 10 parts by weight. Specifically, the weight ratio of lanthanum to lithium G La / G Li It can range from about 3.05 to about 4.99, from about 3.1 to about 4.99, or from about 3.14 to about 4.96. The contents of lanthanum and lithium, as well as the weight ratio of lanthanum to lithium, can be evaluated by ICP analysis.

[0246] The edge layer / capping layer forms the lanthanum to lithium weight ratio G in the composition. La / G Li The weight ratio G of lanthanum to lithium in the solid electrolyte forming composition may be less than that of lithium. La / G Li .

[0247] The edge layer / capping layer forming composition may further include sintering aids, as in the solid electrolyte forming composition.

[0248] Mechanochemical synthesis can include processes such as mechanical milling. Mechanical milling can include, for example, HEMM (Heated Metal Mixture). HEMM refers to the process of applying mechanical energy to combine (bond) components.

[0249] All-solid-state batteries can be manufactured by thermally treating the stack obtained through such a process. An all-solid-state battery can have a structure of first capping layer / positive electrode / solid electrolyte / negative electrode / solid electrolyte / positive electrode / solid electrolyte / negative electrode / second capping layer.

[0250] The heat treatment can be performed at a temperature of about 200°C to about 700°C. For example, the heat treatment can be performed at a temperature of about 200°C to about 600°C or about 200°C to about 550°C. The heat treatment can be performed at a pressure of about 5 MPa to about 300 MPa. The pressure can be in the range of, for example, about 5 MPa to about 250 MPa or about 10 MPa to about 250 MPa. When heat treatment is performed under such conditions, all-solid-state batteries with improved energy density and rate performance can be manufactured.

[0251] The edge layer / capsule forming composition and the solid electrolyte precursor film can be simultaneously heat-treated (co-sintered). Therefore, the edge layer / capsule forming composition and the solid electrolyte precursor film can exhibit similar behavior during the heat treatment process. Specifically, the amorphous material in the edge layer / capsule forming composition can be partially or completely crystallized into pyrochlore crystals through heat treatment, and the amorphous material in the solid electrolyte forming composition can be partially or completely crystallized from amorphous material into garnet cubic crystals through heat treatment. Alternatively, the crystallinity of the pyrochlore crystalline material in the edge layer / capsule forming composition can be increased through heat treatment, and the crystallinity of the garnet cubic crystalline material in the solid electrolyte forming composition can be increased through heat treatment.

[0252] In the following description, specific examples and comparative examples will be given with reference to them, but one or more implementations are not limited to the following examples.

[0253] Reference Example 1: Preparation of Garnet-type Solid Electrolytes

[0254] La₂O₃, ZrO₂, and Ta₂O₅ were mixed in a weight ratio of approximately 6:2:1, and then Li₂O was added to the mixture. The combined mixture was then fed into a high-energy ball mill for dry milling under an inert atmosphere. Li₂O was mixed at a concentration of 16 parts by weight relative to 100 parts by weight of the total weight of La₂O₃, ZrO₂, and Ta₂O₅. (Garnet Li-La-Zr-Ta-O precursor)

[0255] A glass powder having a molar ratio of Li₂O, SiO₂, and B₂O₃ of 50:30:20 was mixed with a mixture and then dry-milled under an inert atmosphere to prepare an amorphous composition. The volume ratio of the mixture to the glass powder in the amorphous composition was 95:5.

[0256] The amorphous composition was subjected to hot pressing sintering (HPS) for 2 hours in air at 450 °C and 250 MPa to prepare an oxide as a sintered body with a thickness of approximately 500 μm. ICP analysis was performed on the oxide. The ICP analysis results are shown in Table 1 below.

[0257] Example 1

[0258] La₂O₃, ZrO₂, and Ta₂O₅ were mixed in a weight ratio of approximately 6:2:1, and then Li₂O was added to the mixture. The combined mixture was then added to a high-energy ball mill for dry milling under an inert atmosphere. Li₂O was mixed in at a concentration of 16 parts by weight relative to 100 parts by weight of the total weight of La₂O₃, ZrO₂, and Ta₂O₅.

[0259] Amorphous compositions were prepared by mixing glass powder (Li-B-Si-O glass powder) having a molar ratio of Li₂O, SiO₂, and B₂O₃ of 50:30:20 with a mixture and dry milling in an inert atmosphere. The volume ratio of the mixture to the glass powder was 50:50. Here, the weight ratio of the mixture to the glass powder was 68:32.

[0260] An amorphous composition was subjected to HPS for 2 hours in an air atmosphere at 450°C and 250 MPa to prepare an oxide as a sintered body with a thickness of approximately 500 μm. ICP analysis of the oxide was performed in the same manner as in Reference Example 1. The ICP analysis results of the oxide are shown in Table 1 below.

[0261] Example 2

[0262] The oxides were prepared in the same manner as in Example 1, except that the volume ratio of the mixture of La₂O₃, ZrO₂, Ta₂O₅, and Li₂O to the glass powder was changed to 60:40. ICP analysis of the oxides was performed in the same manner as in Example 1. The ICP analysis results are shown in Table 1 below. Here, the weight ratio of the mixture to the glass powder was 76:24.

[0263] Example 3

[0264] The oxides were prepared in the same manner as in Example 1, except that the volume ratio of the mixture of La₂O₃, ZrO₂, Ta₂O₅, and Li₂O to the glass powder was changed to 40:60. ICP analysis of the oxides was performed in the same manner as in Example 1. The ICP analysis results are shown in Table 1 below. Here, the weight ratio of the mixture to the glass powder was 59:41.

[0265] Comparative Example 1

[0266] An oxide with a thickness of approximately 500 μm was prepared by subjecting glass powders of Li₂O, SiO₂, and B₂O₃ in a molar ratio of 50:30:20 to HPS for 1 hour in an air atmosphere at a temperature of 450 °C and a pressure of 250 MPa.

[0267] Comparative Example 2

[0268] An oxide with a thickness of approximately 500 μm was prepared by subjecting glass powders of Li₂O, SiO₂, and B₂O₃ in a molar ratio of 50:30:20 to HPS for 1 hour in an air atmosphere at a temperature of 450 °C and a pressure of 50 MPa.

[0269] Evaluation Example 1: X-ray Diffraction Analysis

[0270] XRD spectra of the oxides prepared in Example 1 and Reference Example 1 were measured, and the results are shown in Figure 5 In the middle. Using X'Pert Pro, PANalytical® measured XRD spectra using Cu Kα radiation (1.54056 Å). Figure 5 In this context, Ref. Garnet represents the cubic garnet phase, and Ref. represents the pyrochlore phase.

[0271] like Figure 5 As shown, the oxide of Reference Example 1 exhibits the same diffraction angle characteristics as those of garnet (Ref. garnet) and different diffraction angle characteristics from those of the oxide of Example 1. It is confirmed that the oxide of Reference Example 1 comprises cubic garnet crystalline material as the main phase. Furthermore, as can be seen from the ICP and XRD results, the compound further comprises amorphous materials containing Li, B, and Si.

[0272] like Figure 5As shown, the oxide of Example 1 exhibits diffraction angle characteristics different from those of Reference Example 1. The presence of peaks at diffraction angles 2θ at 28.349° (crystal plane (111)), 47.14° (crystal plane (220)), and 55.93° (crystal plane (311)) confirms that the oxide of Example 1 comprises a pyrochlore phase crystalline material as the main phase. Furthermore, as can be seen from the ICP and XRD results, the compound further comprises amorphous materials containing Li, B, and Si.

[0273] Therefore, it can be confirmed that the oxide of Example 1 can be formed under the same temperature and pressure conditions as those for forming garnet-type solid electrolytes.

[0274] Evaluation Example 2: ICP Analysis

[0275] ICP analysis was performed on the oxides of the sintered bodies obtained according to Examples 1, 2 and 3, Reference Example 1, Comparative Example 1 and Comparative Example 2. The ICP analysis results are listed in Table 1.

[0276] Table 1

[0277]

[0278] As shown in Table 1, the La / Li weight ratios obtained by ICP analysis in the oxides of Examples 1, 2, and 3 were 3.96, 4.96, and 3.14, respectively, falling within the range of 3-5. In contrast, the oxide of Reference Example 1 had a La / Li weight ratio of 8.05, which exceeded 5, and thus exhibited a different composition from the oxides of Examples 1 to 3.

[0279] Evaluation Example 3: Measurement of Electronic and Ionic Conductivity

[0280] Shielding electrodes (blocking electrodes) were deposited by sputtering gold (Au) electrodes onto the opposite sides of the oxide wafers prepared in Reference Examples 1, Examples 1, 2, and 3, and Comparative Examples 1 and 2. The impedance of the samples having the shielding electrodes formed on their opposite sides was measured using a two-probe method with an impedance analyzer (Solartron 1400A / 1455A impedance analyzer). The frequency was in the range of 1 Hz to 1 MHz, and the amplitude voltage was 10 mV. Measurements were performed at 25°C in a dry (less than 15% humidity) air atmosphere. Resistance values ​​were obtained from the arcs of the Nyquist plot of the impedance measurement results, and the electrode area and wafer thickness were corrected from the resistance values ​​to calculate ionic and electronic conductivity. The results are shown in Table 2 below.

[0281] Evaluation Example 4: Density (Relative Density)

[0282] The densities of the oxides prepared according to Reference Example 1, Examples 1, 2 and 3, and Comparative Examples 1 and 2 are listed in Table 2. The density of the discs was obtained as the ratio of the measured density to the theoretical density. Here, the measured density was determined by using a densitometer based on Archimedes' principle or by the apparent volume and weight of the discs. The theoretical density of garnet Li-La-Zr-Ta-O was considered to be 5.5 g / cm³. 3 The theoretical density of Li-B-Si-O glass powder is 2.4 g / cm³. 3 The theoretical density of the disc is determined by the ratio of the sample to its mixture.

[0283] Evaluation Example 5: Evaluation of whether the disc shape is preserved

[0284] Oxides were prepared according to Reference Example 1, Examples 1, 2, and 3, and Comparative Examples 1 and 2, and the oxides were formed into discs. The disc oxides were investigated to evaluate process compatibility. If they did not maintain their cylindrical shape in appearance, the retention of their disc form was evaluated by examining the weight change of the sample injected before sintering. In other words, it was evaluated by examining the degree to which they liquefied during pressurization and disappeared outside the mold. If it was less than 20% of the weight of the sample injected before sintering, it was marked with ×, and if it was 20% or more, it was marked with ○. The evaluation results are shown in Table 2.

[0285] Table 2

[0286]

[0287] As shown in Table 2, individual glass powders of Li₂O, SiO₂, and B₂O₃ could not form or maintain their shape under HPS conditions (450°C, 250 MPa, and 1 h), as demonstrated in Comparative Example 1. Comparative Example 2 could only form and maintain its shape under HPS conditions (450°C, 50 MPa, and 1 h). That is, glass powders of Li₂O, SiO₂, and B₂O₃ could not achieve the desired ionic conductivity, electronic conductivity, density, shape, etc., under the same conditions (450°C, 250 MPa, and 2 h) as those used to form the garnet-type solid electrolyte of Reference Example 1. Therefore, glass powders of Li₂O, SiO₂, and B₂O₃ may have poor process compatibility with garnet-type solid electrolytes and may not be suitable as edge layer / capping layer materials.

[0288] As shown in Table 2, the oxides of Examples 1, 2, and 3 can be formed and maintain their shape under the same conditions (450°C, 250 MPa, and 2 hours) as those used to form the garnet-type solid electrolyte of Reference Example 1. Therefore, the oxides of Examples 1, 2, and 3 exhibit good process compatibility with the garnet-type solid electrolyte. Furthermore, the oxides of Examples 1, 2, and 3 have a higher density than the garnet-type solid electrolyte of Reference Example 1. Therefore, the oxides of Examples 1, 2, and 3 are suitable as edge layer / capping layer materials for all-solid-state batteries using garnet-type solid electrolytes.

[0289] Although embodiments have been described above, one or more embodiments are not limited thereto and can be embodied in various ways by modifications within the scope of the claims, detailed description, and drawings. It is clear that such modifications fall within the scope of this disclosure.

[0290] According to one aspect, an all-solid-state battery can be manufactured, comprising an edge layer and / or a cover layer capable of effectively protecting the internal cell units from external environmental influences. The all-solid-state battery may have improved energy density and rate performance.

[0291] It should be understood that the embodiments described herein are to be considered in the descriptive sense only and are not intended for limiting purposes. The descriptions of features or aspects in each embodiment should typically be considered applicable to other similar features or aspects in other embodiments. Although one or more embodiments have been described with reference to the accompanying drawings, those skilled in the art will understand that various changes in form and detail may be made therein without departing from the spirit and scope defined by the appended claims.

Claims

1. All-solid-state batteries, including: Multi-layer structure; A first cover layer stacked on the first outermost layer of the multilayer structure in the stacking direction; and A second cover layer disposed opposite to the first cover layer and on the second outermost stack of the multilayer structure in the stacking direction. The multi-layer structure includes: A solid electrolyte layer including a solid electrolyte; A positive electrode layer is provided on a first side of the solid electrolyte layer, wherein a portion of the positive electrode layer extends to a first edge of the solid electrolyte layer; A first edge layer is provided on a region on a first side of the solid electrolyte layer in which the positive electrode layer is not present, the region on the first side of the solid electrolyte layer including a region adjacent to a second edge of the solid electrolyte opposite to the first edge; A negative electrode layer is provided on the opposite second side of the solid electrolyte layer, wherein a portion of the negative electrode layer extends to the second edge of the solid electrolyte layer; and A second edge layer is provided on a region on the second side of the solid electrolyte layer in which the negative electrode layer is not present, the region on the second side of the solid electrolyte layer including a region adjacent to the first edge of the solid electrolyte layer. At least one of the first covering layer, the second covering layer, the first edge layer, or the second edge layer comprises an oxide, wherein the oxide comprises pyrochlore crystal material.

2. The all-solid-state battery according to claim 1, wherein the pyrochlore crystalline material is a compound represented by formula 1: Formula 1 (La 1-a B a ) 2+nx Zr 2-(n+1)x C x O7 in, In Equation 1, B is one or more trivalent cations. C is one or more tetravalent cations, one or more pentavalent cations, or one or more hexavalent cations. 0 ≤ a < 1, 0 ≤ x < 0.66, and n = (oxidation number of C) - (oxidation number of Zr).

3. The all-solid-state battery according to claim 2, wherein, In Formula 1, B includes scandium (Sc), yttrium (Y), aluminum (Al), gallium (Ga), or indium (In), and C includes tungsten (W), niobium (Nb), bismuth (Bi), antimony (Sb), or tantalum (Ta).

4. The all-solid-state battery according to claim 1, wherein the pyrochlore crystalline material is a compound represented by formula 2: Formula 2 La 2+x Zr 2-2x Ta x O7 in, In Equation 2, 0 ≤ x < 0.

66.

5. The all-solid-state battery according to claim 1, wherein the peaks in the X-ray diffraction (XRD) spectrum of the oxide appear at diffraction angles (2θ) of 27.5° to 29°, 32° to 33.5°, 46.5° to 48°, and 55° to 56.5°.

6. The all-solid-state battery according to claim 1, wherein the oxide further comprises an amorphous material.

7. The all-solid-state battery according to claim 1, wherein the content of the pyrochlore crystalline material in the oxide is in the range of 50 parts by weight to 99.9 parts by weight relative to the total weight of 100 parts by weight of the oxide.

8. The all-solid-state battery according to claim 1, wherein the lanthanum to lithium weight ratio G in at least one of the first capping layer, the second capping layer, the first edge layer, or the second edge layer is [missing information]. La / G Li Within the range of 3 to 5.

9. The all-solid-state battery of claim 1, wherein the oxide has a lower ionic conductivity than the solid electrolyte.

10. The all-solid-state battery according to claim 1, wherein the oxide has a density of 1.0 × 10⁻⁶. -8 S / cm or even lower ionic conductivity.

11. The all-solid-state battery of claim 1, wherein at least one of the first capping layer, the second capping layer, the first edge layer, or the second edge layer has a density of less than 1.0 × 10⁻⁶. -7 Electron conductivity in S / cm.

12. The all-solid-state battery of claim 1, further comprising a third edge layer disposed on an extension plane of the solid electrolyte layer, wherein the third edge layer includes a region disposed between the first edge layer and the second edge layer.

13. The all-solid-state battery of claim 1, wherein the lanthanum to lithium weight ratio G of at least one of the first capping layer, the second capping layer, the first edge layer, or the second edge layer is [missing information]. La / G Li The weight ratio of lanthanum to lithium less than that of the solid electrolyte layer (G) La / G Li .

14. A method for manufacturing an all-solid-state battery according to any one of claims 1 to 13, the method comprising: Prepare a positive electrode structure having a first edge layer that does not overlap with the positive electrode layer to form a composition; A negative electrode structure is prepared having a second edge layer that does not overlap with the negative electrode layer to form the composition; A multilayer structure is formed, the multilayer structure having a solid electrolyte forming composition disposed between the positive electrode structure and the negative electrode structure; A first cover layer is provided on the first outermost layer of the multilayer structure to form a composition; A second cover layer is provided on the second outermost layer of the multilayer structure to form a composition to provide a stack, the second outermost layer being disposed opposite to the first outermost layer of the multilayer structure; and The stack is heat-treated.

15. The method of claim 14, wherein the heat treatment of the stack is performed at a temperature of 200°C to 700°C.

16. The method of claim 14, wherein the heat treatment of the stack is performed under pressure conditions of 5 MPa to 300 MPa.

17. The method of claim 14, wherein at least one of the first edge layer forming composition, the second edge layer forming composition, the first cover layer forming composition, or the second cover layer forming composition comprises pyrochlore crystal material, pyrochlore crystal material precursor, or a combination thereof.

18. The method of claim 17, wherein at least one of the first edge layer forming composition, the second edge layer forming composition, the first cover layer forming composition, or the second cover layer forming composition further comprises an amorphous material, an amorphous material precursor, or a combination thereof.

19. The method of claim 14, wherein the solid electrolyte forming composition comprises a garnet-type solid electrolyte, a garnet-type solid electrolyte precursor, or a combination thereof.

20. The method of claim 14, wherein the weight ratio G of lanthanum to lithium of at least one of the first edge layer forming composition, the second edge layer forming composition, the first capping layer forming composition, or the second capping layer forming composition is [missing information]. La / G Li The lanthanum-to-lithium weight ratio G of the solid electrolyte forming composition is less than that of the solid electrolyte forming composition. La / G Li .

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