Solid-state battery and method for manufacturing solid-state battery

Abstract

A solid-state battery and a method of manufacturing a solid-state battery. The solid-state battery includes: a positive electrode; a negative electrode; and a solid electrolyte layer between the positive electrode and the negative electrode. The solid electrolyte layer includes one or more sub-solid electrolyte layers. The solid electrolyte layer includes or does not include an interlayer between the plurality of sub-solid electrolyte layers. At least one of the sub-solid electrolyte layers and the interlayer includes a tackifier. The tackifier includes a hydrocarbon oligomer derived from an aliphatic chain monomer having 5 carbon atoms to 20 carbon atoms, an aromatic ring monomer having 6 carbon atoms to 20 carbon atoms, an aliphatic ring monomer having 5 carbon atoms to 20 carbon atoms, or a combination thereof.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to and all rights arising therefrom of Korean Patent Application No. 10-2024-0177908 filed on December 3, 2024, and Korean Patent Application No. 10-2025-0188565 filed on December 2, 2025, the entire disclosure of which is incorporated herein by reference. Technical Field

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

[0004] Lithium-ion batteries may include liquid electrolytes containing flammable solvents, and therefore, in the event of a short circuit, the battery may be at risk of overheating and catching fire. In view of this problem, lithium-ion batteries using solid electrolytes instead of liquid electrolytes have been proposed.

[0005] In the manufacturing process of lithium-ion batteries containing liquid electrolytes, injecting the liquid electrolyte into the battery allows it to permeate into the electrodes, thereby reducing the interfacial resistance between the electrodes and the liquid electrolyte. In contrast, in the manufacturing process of lithium-ion batteries containing solid electrolytes, applying a high voltage to the battery reduces the interfacial resistance between the electrodes and the solid electrolyte. Summary of the Invention

[0006] A solid-state battery including an electrolyte layer is provided, which has increased ionic conductivity and reduced internal resistance by having improved bonding strength and tackiness.

[0007] A method for preparing solid-state batteries is provided.

[0008] According to one aspect of this disclosure, a solid-state battery includes:

[0009] Positive electrode; negative electrode; and a solid electrolyte layer between the positive electrode and the negative electrode.

[0010] The solid electrolyte layer includes one or more sub-solid electrolyte layers.

[0011] The solid electrolyte layer may include an interlayer (intermediate layer) between the plurality of sub-solid electrolyte layers or may not include the interlayer.

[0012] At least one of the sub-solid electrolyte layer and the interlayer includes a thickener.

[0013] The tackifier comprises hydrocarbon oligomers (hydrocarbon oligomers) derived from (or derived from) aliphatic chain monomers having 5 to 20 carbon atoms, aromatic cyclic monomers having 6 to 20 carbon atoms, aliphatic cyclic monomers having 5 to 20 carbon atoms, or combinations thereof.

[0014] According to another aspect of this disclosure, a method for preparing a solid-state battery includes:

[0015] A first laminate including a positive electrode and a first solid electrolyte layer on the positive electrode is provided, and a second laminate including a negative electrode and a second solid electrolyte layer on the negative electrode is provided;

[0016] An interlayer is provided on one or more surfaces of the first solid electrolyte layer of the first laminate and the second solid electrolyte layer of the second laminate;

[0017] Stacking the first laminate and the second laminate such that the first solid electrolyte layer of the first laminate and the second solid electrolyte layer of the second laminate face each other to provide a third laminate; and

[0018] Pressure is applied to the third stack to manufacture the solid battery, wherein the interlayer includes a thickener.

[0019] According to another aspect of this disclosure, a method for preparing a solid-state battery includes:

[0020] A first laminate including a positive electrode and a third solid electrolyte layer on the positive electrode is provided, and a second laminate including a negative electrode and a fourth solid electrolyte layer on the negative electrode is provided;

[0021] Stack the first laminate and the second laminate such that the third solid electrolyte layer of the first laminate and the fourth solid electrolyte layer of the second laminate face each other to provide a third laminate; and

[0022] Pressure is applied to the third stack to prepare the solid battery, wherein one or more of the third solid electrolyte layer and the fourth solid electrolyte layer include a thickener. Attached Figure Description

[0023] The above and other aspects, features and advantages of some embodiments of this disclosure will become more apparent from the following description taken in conjunction with the accompanying drawings, wherein:

[0024] Figure 1 A schematic cross-sectional view of a solid electrolyte layer including a first structure according to one embodiment;

[0025] Figure 2This is a schematic cross-sectional view of a solid electrolyte layer including a first structure according to another embodiment;

[0026] Figure 3 This is a schematic cross-sectional view of a solid electrolyte layer including a second structure according to one embodiment;

[0027] Figure 4 This is a schematic cross-sectional view of a solid electrolyte layer including a second structure according to another embodiment;

[0028] Figure 5 A schematic cross-sectional view of a solid electrolyte layer including a third structure according to one embodiment;

[0029] Figure 6 This is a schematic cross-sectional view of a solid electrolyte layer including a third structure according to another embodiment;

[0030] Figure 7 For including Figure 1 A schematic cross-sectional view of a solid-state battery with a solid electrolyte layer;

[0031] Figure 8 For including Figure 2 A schematic cross-sectional view of a solid-state battery with a solid electrolyte layer;

[0032] Figure 9 For including Figure 3 A schematic cross-sectional view of a solid-state battery with a solid electrolyte layer;

[0033] Figure 10 For including Figure 5 A schematic cross-sectional view of a solid-state battery with a solid electrolyte layer;

[0034] Figure 11 A schematic cross-sectional view of a solid-state battery including a solid electrolyte layer;

[0035] Figure 12 A schematic cross-sectional view of a solid battery including a solid electrolyte layer and a metal layer;

[0036] Figures 13A to 13G A cross-sectional view showing the method for preparing a solid-state battery according to an embodiment; and

[0037] Figure 14 A graph showing the capacity change of the solid battery prepared in Example 3 during charge and discharge cycles. Detailed Implementation

[0038] Embodiments will now be described in detail, examples of which are shown in the accompanying drawings, wherein the same reference numerals always refer to the same elements. In this respect, 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 explain aspects.

[0039] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. Expressions such as "at least one of..." when preceding or following a list of elements modify the entire list of elements, but not any individual element of the list.

[0040] Various embodiments have been illustrated in the accompanying drawings. However, the inventive concept can be embodied in many other forms and should not be construed as limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure is thorough and complete, and fully conveys the scope of the inventive concept to those skilled in the art.

[0041] Embodiments are described in this disclosure with reference to cross-sectional views of idealized embodiments. For example, variations in shape from the figures are anticipated as a result of manufacturing techniques and / or tolerances. Therefore, the embodiments described in this disclosure should not be construed as limited to the specific shapes of the areas depicted in the figures, but should include, for example, deviations in shape due to manufacturing processes. For instance, areas illustrated or described as flat may be rough and / or include non-linear features. Furthermore, sharp corners may be rounded. Thus, the areas depicted in the figures are schematic in nature, and their shapes are not intended to describe the precise shapes of the areas or limit the scope of this disclosure. Throughout this disclosure, the same reference numerals always refer to the same elements.

[0042] Terms such as “first,” “second,” and “third” may be used herein to describe various components, ingredients, regions, layers, and / or areas, but are not limited by these terms. These terms are used only to distinguish one component, ingredient, region, layer, or area from another. Therefore, without departing from the teachings of this disclosure, the first component, ingredient, region, layer, or area described below may be referred to as the second component, ingredient, region, layer, or area.

[0043] Understandably, when a component is referred to as being "on" another component, it can be directly on top of the other component, or there can be an intermediate component between them. Conversely, when a component is referred to as being "directly on" another component, there is no intermediate component between them.

[0044] As used herein, the singular forms “a (kind) (indefinite article) (a, an)” and “the” are intended to include the plural forms, including “at least one (kind)”, unless the context clearly indicates otherwise. The word “at least one (kind)” should not be construed as limited to the singular. As used herein, the term “and / or” includes any and all combinations of one or more of the listed items. When used in a detailed description, the terms “comprising” and / or “including” indicate the presence of the stated features, regions, wholes, steps, operations, elements, components (components), and / or ingredients, but do not preclude the presence or addition of one or more other features, regions, wholes, steps, operations, elements, components (components), and / or collections thereof.

[0045] 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. Furthermore, terms defined in commonly used dictionaries shall be interpreted as having the meaning consistent with their meaning in the context of this disclosure and the relevant field, and shall not be interpreted in an idealized or overly formal sense.

[0046] As used in this article, “group” refers to a group in the periodic table of elements according to the International Union of Pure and Applied Chemistry (“IUPAC”) Group 1-18 classification system.

[0047] As used herein, "particle diameter" refers to the average diameter of the particle when the particle is spherical, or the average major axis length when the particle is non-spherical. The particle diameter can be measured using a particle size analyzer (PSA). For example, "particle diameter" refers to the average particle diameter. For example, the average particle diameter is the median particle diameter (D50).

[0048] As used herein, “metal” includes both elements or ionic states of the following: metals and metalloids such as silicon and germanium.

[0049] As used herein, “alloy” means a metallic material comprising two or more elements, wherein at least one of the elements is a metal as defined herein.

[0050] As used in this article, “electrode active material” refers to an electrode material that can undergo lithiation and delithiation.

[0051] In this article, "positive electrode active material" refers to a positive electrode material that can undergo lithiation and delithiation.

[0052] In this article, "negative electrode active material" refers to a negative electrode material that can undergo lithiation and delithiation.

[0053] As used in this article, "lithiation" refers to the process of adding lithium to the electrode active material.

[0054] As used in this article, “delithiation” refers to the process of removing lithium from the electrode active material.

[0055] As used in this article, “charging” refers to the process of providing electrochemical energy to a battery.

[0056] As used in this article, “discharging” refers to the process of removing electrochemical energy from a battery.

[0057] As used in this article, "positive electrode" and "positive electrode" refer to the electrode that undergoes electrochemical reduction and lithiation during the discharge process.

[0058] As used in this article, "negative electrode" and "negative electrode" refer to the electrode that undergoes electrochemical oxidation and delithiation during the discharge process.

[0059] As used herein, "free of tackifier" or "free of the tackifier" means that the material or substance does not contain an experimentally detectable amount of tackifier.

[0060] Although specific embodiments have been described, the applicant or those skilled in the art will recognize alternatives, modifications, variations, improvements, and substantial equivalents that are not currently foreseen or unforeseen. Therefore, the appended claims, as filed and as amended, are intended to cover all such alternatives, modifications, variations, improvements, and substantial equivalents.

[0061] Because liquid electrolytes are in a liquid state, they readily adapt to volume changes within the lithium-ion battery during charge and discharge cycles. Therefore, in lithium-ion batteries containing liquid electrolytes, the likelihood of pore formation, cracking, and electrical disconnection in the electrolyte layer due to volume changes during charge and discharge cycles is relatively low. In contrast, lithium-ion batteries using solid electrolytes face difficulties adapting to volume changes during charge and discharge cycles. Specifically, the likelihood of pore formation, cracking, and electrical disconnection in the electrolyte layer due to volume changes during charge and discharge cycles is relatively high in lithium-ion batteries using solid electrolytes. Therefore, it is necessary to effectively suppress pore formation, cracking, and electrical disconnection caused by volume changes within the lithium-ion battery during charge and discharge cycles in lithium-ion batteries containing solid electrolytes.

[0062] The solid-state battery according to the embodiments and the method for preparing the solid-state battery will be described in more detail below.

[0063] solid-state batteries

[0064] According to an embodiment, a solid-state battery may include: a positive electrode; a negative electrode; and a solid electrolyte layer between the positive electrode and the negative electrode. The solid electrolyte layer includes one or more sub-solid electrolyte layers. The solid electrolyte layer may include an interlayer (intermediate layer) between the plurality of sub-solid electrolyte layers or may not include the interlayer. At least one of the sub-solid electrolyte layers and the interlayer includes a thickener. The thickener includes hydrocarbon oligomers (hydrocarbon oligomers) derived from (or derived from) aliphatic chain monomers having 5 to 20 carbon atoms, aromatic cyclic monomers having 6 to 20 carbon atoms, aliphatic cyclic monomers having 5 to 20 carbon atoms, or combinations thereof. The thickener may also include hydrocarbon oligomers (hydrocarbon oligomers) derived from (or derived from) aliphatic chain monomers having 5 to 20 carbon atoms, aromatic cyclic monomers having 9 to 20 carbon atoms, aliphatic cyclic monomers having 10 to 20 carbon atoms, or combinations thereof. The sub-solid electrolyte layer may include a first solid electrolyte layer, a second solid electrolyte layer, a third solid electrolyte layer, a fourth solid electrolyte layer, and a fifth solid electrolyte layer. The solid electrolyte layer may include a first structure comprising the first solid electrolyte layer, the second solid electrolyte layer, and a first interlayer therebetween. The solid electrolyte layer may include a second structure comprising the third and fourth solid electrolyte layers. The solid electrolyte layer may include a third structure comprising the fifth solid electrolyte layer. In the first structure, for example, the interlayer may include a tackifier. In the second structure, for example, one or both of the third and fourth solid electrolyte layers may include a tackifier. In the third structure, for example, the fifth solid electrolyte layer may include a tackifier. The tackifier may include, for example, an organic tackifier. The tackifier may not include, for example, an inorganic tackifier.

[0065] Including binders and tackifiers in the solid electrolyte layer can improve the viscoelasticity and / or resilience of the solid electrolyte layer. Including binders and tackifiers in the solid electrolyte layer can improve the bonding strength between the solid electrolyte layer and the positive and / or negative electrode. Including binders and tackifiers in the solid electrolyte layer can improve the bonding strength between multiple solid electrolyte layers included in the solid electrolyte layer. Including binders and tackifiers in the solid electrolyte layer can reduce the porosity within the solid electrolyte layer. Including binders and tackifiers in the solid electrolyte layer can suppress the occurrence of pores, cracks, or electrical disconnections within the solid electrolyte layer during charge and discharge cycles of the solid secondary battery. This can enhance the charge and discharge characteristics of the solid secondary battery including the solid electrolyte layer.

[0066] Tackifiers may include mixtures of various hydrocarbon oligomers with different structures. Tackifiers may include mixtures of three or more, five or more, seven or more, or ten or more hydrocarbon oligomers with different structures. By incorporating a tackifier comprising a mixture of various hydrocarbon oligomers with different structures into the solid electrolyte layer, the viscoelasticity and / or resilience of the solid electrolyte layer can be improved.

[0067] The number of repeating units in the hydrocarbon oligomer can be 100 or less, 50 or less, 30 or less, 25 or less, 20 or less, 15 or less, or 10 or less. The number of repeating units in the hydrocarbon oligomer can be 2 to 100, 2 to 50, 2 to 30, 2 to 25, 2 to 20, 2 to 15, or 2 to 10. By placing the number of repeating units in the hydrocarbon oligomer within these ranges, the viscoelasticity and / or resilience of the solid electrolyte layer can be improved.

[0068] The tackifier may further comprise unreacted monomers, including aliphatic monomers having 5 to 20 carbon atoms, aromatic cyclic monomers having 6 to 20 carbon atoms, aliphatic cyclic monomers having 5 to 20 carbon atoms, or combinations thereof. Based on the total weight of the tackifier, the amount of unreacted monomers in the tackifier may be about 0.1% by weight or more, about 0.5% by weight or more, or about 1% by weight or more. Based on the total weight of the tackifier, the amount of unreacted monomers in the tackifier may be about 0.1% by weight to about 10% by weight, about 0.5% by weight to 8% by weight, or about 1% by weight to about 5% by weight.

[0069] Tackifiers may include, for example, i) unsaturated aliphatic hydrocarbon chain monomers having 5 to 20 carbon atoms, oligomers of unsaturated aliphatic hydrocarbon chain monomers having 5 to 20 carbon atoms, or combinations thereof. Tackifiers may also include, for example, i-1) hydrides of unsaturated aliphatic hydrocarbon chain monomers having 5 to 20 carbon atoms, hydrides of oligomers of unsaturated aliphatic hydrocarbon chain monomers having 5 to 20 carbon atoms, or combinations thereof. Tackifiers may also include, for example, ii) unsaturated aromatic hydrocarbon ring monomers having 6 to 20 carbon atoms, oligomers of unsaturated aromatic hydrocarbon ring monomers having 6 to 20 carbon atoms, unsaturated aromatic hydrocarbon ring monomers having 9 to 20 carbon atoms, oligomers of unsaturated aromatic hydrocarbon ring monomers having 9 to 20 carbon atoms, or combinations thereof. Tackifiers may include, for example, ii-1) hydrides of unsaturated aromatic ring monomers having 6 to 20 carbon atoms, hydrides of oligomers of unsaturated aromatic ring monomers having 6 to 20 carbon atoms, hydrides of unsaturated aromatic ring monomers having 9 to 20 carbon atoms, hydrides of oligomers of unsaturated aromatic ring monomers having 9 to 20 carbon atoms, or combinations thereof. Tackifiers may also include, for example, iii) unsaturated aliphatic ring monomers having 5 to 20 carbon atoms, oligomers of unsaturated aliphatic ring monomers having 5 to 20 carbon atoms, unsaturated aliphatic ring monomers having 10 to 20 carbon atoms, oligomers of unsaturated aliphatic ring monomers having 10 to 20 carbon atoms, or combinations thereof. Tackifiers may include, for example, iii-1) hydrides of unsaturated aliphatic cyclic monomers having 5 to 20 carbon atoms, hydrides of oligomers of unsaturated aliphatic cyclic monomers having 5 to 20 carbon atoms, hydrides of unsaturated aliphatic cyclic monomers having 10 to 20 carbon atoms, hydrides of oligomers of unsaturated aliphatic cyclic monomers having 10 to 20 carbon atoms, or combinations thereof. By including these tackifiers in solid-state batteries, the internal resistance of the solid-state battery can be reduced, and the charging and discharging characteristics of the solid-state battery can be improved.

[0070] Tackifiers may include, for example, i) trans-1,3-pentadiene, oligomers of trans-1,3-pentadiene, oligomers of cis-1,3-pentadiene, 2-methyl-2-butene, oligomers of 2-methyl-2-butene, or combinations thereof. Tackifiers may also include, for example, i-1) hydrides of trans-1,3-pentadiene, hydrides of trans-1,3-pentadiene oligomers, hydrides of cis-1,3-pentadiene, hydrides of cis-1,3-pentadiene oligomers, hydrides of 2-methyl-2-butene, hydrides of 2-methyl-2-butene oligomers, or combinations thereof. Tackifiers may also include, for example, ii) styrene, oligomers of styrene, α-methylstyrene, oligomers of α-methylstyrene, vinyltoluene, oligomers of vinyltoluene, indene, oligomers of indene, or combinations thereof. Tackifiers may include, for example, ii-1) hydrides of styrene, hydrides of styrene oligomers, hydrides of α-methylstyrene, hydrides of α-methylstyrene oligomers, hydrides of vinyltoluene, hydrides of vinyltoluene oligomers, hydrides of indene, hydrides of indene oligomers, or combinations thereof. Tackifiers may also include, for example, iii) cyclopentene, oligomers of cyclopentene, cyclopentadiene, oligomers of cyclopentadiene, dicyclopentadiene, oligomers of dicyclopentadiene, or combinations thereof. Tackifiers may also include, for example, iii-1) hydrides of cyclopentene, hydrides of cyclopentene oligomers, hydrides of cyclopentadiene, oligomers of cyclopentadiene, hydrides of dicyclopentadiene, oligomers of dicyclopentadiene, or combinations thereof. By including these tackifiers in the solid-state battery, the internal resistance of the solid-state battery can be reduced, and the charging and discharging characteristics of the solid-state battery can be improved. Tackifiers may be free of oxygen, nitrogen, fluorine, chlorine, sulfur, phosphorus, or combinations thereof.

[0071] Tackifiers may include, for example, repeating ring units comprising aliphatic hydrocarbon rings, repeating ring units comprising aromatic hydrocarbon rings, or combinations thereof. Organic tackifiers may include, for example, repeating ring units comprising aliphatic hydrocarbon rings having about 5 to about 20 carbon atoms, repeating ring units comprising aromatic hydrocarbon rings having about 6 to about 20 carbon atoms, or combinations thereof. Aliphatic hydrocarbon rings may include, for example, saturated aliphatic hydrocarbon rings having about 5 to about 20 carbon atoms, unsaturated aliphatic hydrocarbon rings having about 5 to about 20 carbon atoms, or combinations thereof. By including such repeating units in the tackifier, the adhesiveness of the organic tackifier can be further improved.

[0072] The tackifier may further include a chain repeating unit, which comprises, for example, an aliphatic hydrocarbon chain having about 4 to about 20 carbon atoms. The aliphatic chain having about 4 to about 20 carbon atoms may include, for example, a saturated aliphatic hydrocarbon chain having about 4 to about 20 carbon atoms, an unsaturated aliphatic hydrocarbon chain having about 4 to about 20 carbon atoms, or a combination thereof. By further including a chain repeating unit (which comprises an aliphatic hydrocarbon chain having about 4 to about 20 carbon atoms) in the tackifier, the adhesiveness of the tackifier can be further improved.

[0073] Tackifiers may, for example, comprise repeating units derived from unsaturated hydrocarbon monomers. Unsaturated hydrocarbon monomers may include, for example, aliphatic monomers, aromatic monomers, or combinations thereof. Aliphatic monomers may include, for example, aliphatic chain monomers, aliphatic cyclic monomers, or combinations thereof. Unsaturated hydrocarbon monomers may include, for example, aliphatic monomers having about 4 to about 20 carbon atoms, aromatic monomers having about 6 to about 20 carbon atoms, or combinations thereof. Aliphatic monomers having about 4 to about 20 carbon atoms may include, for example, aliphatic chain monomers having about 4 to about 20 carbon atoms, aliphatic cyclic monomers having about 5 to about 20 carbon atoms, or combinations thereof.

[0074] The tackifier may include at least one or more repeating units, such as a first repeating unit, a second repeating unit, or a third repeating unit. The first repeating unit may be derived from, for example, isoprene, isoprene, 2-methyl-2-butene, or combinations thereof. The second repeating unit may be derived from, for example, cyclopentene, cyclopentadiene (CPD), dicyclopentadiene (DCPD), or combinations thereof. The third repeating unit may be derived from, for example, styrene, α-methylstyrene, vinyltoluene, indene, or combinations thereof.

[0075] Unsaturated hydrocarbon monomers may include, for example, byproducts of naphtha cracking. Unsaturated hydrocarbon monomers may include, for example, C5 fractions, C9 fractions, naphtha cracking byproducts, dicyclopentadiene (DCPD), or combinations thereof. The C5 fraction may include, for example, unsaturated C5 fractions, unsaturated C6 fractions, or combinations thereof. The C9 fraction may include, for example, unsaturated aromatic C8 fractions, unsaturated aromatic C9 fractions, unsaturated aromatic C10 fractions, or combinations thereof.

[0076] Tackifiers may include, for example, hydrocarbon resins. Hydrocarbon resins may include, for example, hydrogenated hydrocarbon resins, non-hydrogenated hydrocarbon resins, or combinations thereof. Hydrocarbon resins may, for example, comprise repeating units derived from (or derived from) a variety of monomers. Hydrocarbon resins may include repeating units derived from, for example, combinations of three or more different monomers, combinations of four or more different monomers, combinations of five or more different monomers, combinations of seven or more different monomers, or combinations of ten or more different monomers.

[0077] Hydrocarbon resins may include, for example, C5 resins derived from (or derived from) C5 fractions, acid-modified C5 resins, C9 resins derived from (or derived from) C9 fractions, phenol-modified C9 resins, C5-C9 copolymer resins, DCPD resins derived from (or derived from) dicyclopentadiene (DCPD), DCPD-C9 copolymer resins, DCPD-C5 copolymer resins, hydrogenated C5 resins, hydrogenated acid-modified C5 resins, hydrogenated C9 resins, hydrogenated phenol-modified C9 resins, hydrogenated C5-C9 copolymer resins, hydrogenated DCPD resins, hydrogenated DCPD-C9 copolymer resins, hydrogenated DCPD-C5 copolymer resins, or combinations thereof.

[0078] The hydrocarbon resin may include, for example, a C5-C9 copolymer resin derived from (or derived from) C5 and C9 fractions. The C9 fraction content relative to the total C5 and C9 fractions may be, for example, 10 wt% or more, 20 wt% or more, 30 wt% or more, or 50 wt% or more. The C9 fraction content relative to the total C5 and C9 fractions may be, for example, about 10 wt% to about 90 wt%, about 20 wt% to about 90 wt%, about 30 wt% to about 90 wt%, or about 50 wt% to about 90 wt%. A high C9 fraction content can further improve the cycle characteristics of the solid-state battery employing a solid electrolyte layer 30 including a hydrocarbon resin.

[0079] Tackifiers can be amorphous. Tackifiers may include amorphous hydrocarbon oligomers. Amorphous properties can be measured, for example, by X-ray diffraction (XRD). Tackifiers may include hydrocarbon oligomers having a molecular weight of less than about 10,000 Daltons. The molecular weight of the tackifier may be, for example, less than about 10,000 Daltons, about 8,000 Daltons or less, about 5,000 Daltons or less, or about 3,000 Daltons or less. The molecular weight of the tackifier may be, for example, about 100 Daltons to about 10,000 Daltons, about 300 Daltons to about 8,000 Daltons, about 500 Daltons to about 5,000 Daltons, or about 500 Daltons to about 3,000 Daltons. The molecular weight of the tackifier can be measured using gel permeation chromatography with a polystyrene standard sample. The molecular weight of the tackifier may be a weight-average molecular weight. By having a molecular weight within these ranges, the tackifier provides excellent adhesion. Tackifiers with this molecular weight range can be easily mixed with adhesives, thereby more effectively improving the bonding strength of the adhesive.

[0080] Tackifiers may include hydrocarbon oligomers having a softening point of about 190°C or lower, about 180°C or lower, about 160°C or lower, about 140°C or lower, or about 120°C or lower, as measured by ASTM E 28. The softening point of the tackifier as measured by ASTM E 28 may be, for example, about 0°C to about 190°C, about 0°C to about 180°C, about 0°C to about 160°C, about 80°C to about 140°C, or about 80°C to about 120°C. By making the softening point of the tackifier within these ranges, the viscoelasticity of the interlayer can be improved more effectively.

[0081] Tackifiers may include hydrocarbon oligomers having a glass transition temperature of less than about 160°C. The glass transition temperature of the tackifier may be, for example, from about 30°C to about 160°C. By keeping the glass transition temperature within this range, the tackifier can be mixed more effectively with the adhesive. The glass transition temperature may be measured, for example, using differential scanning calorimetry (DSC).

[0082] At 25°C and 1 atm, tackifiers can exist as liquids or solids. Liquid tackifiers are readily mixable with adhesives. Solid tackifiers are soluble in solvents to promote mixing with adhesives.

[0083] The interlayer may further include an adhesive. The adhesive may be a polymer comprising, for example, carbon, hydrogen, and heteroatoms. Heteroatoms may include, for example, oxygen, nitrogen, fluorine, chlorine, sulfur (S), phosphorus (P), or combinations thereof. The molecular weight of the adhesive may be, for example, 100,000 Daltons or greater, 150,000 Daltons or greater, 200,000 Daltons or greater, 300,000 Daltons or greater, or 500,000 Daltons or greater. By maintaining a molecular weight within this range, the adhesive provides excellent bonding strength. The molecular weight of the adhesive may be measured, for example, using gel permeation chromatography with a polystyrene standard sample.

[0084] Examples of adhesives may include nitrile rubber (NR), nitrile-butadiene rubber (NBR), nitrile-isoprene rubber (NIR), polydimethylsiloxane (PDMS), ethylene vinyl acetate (EVA), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), polyacrylonitrile (PAN), alkyl polyacrylate, polymethyl methacrylate (PMMA), polyvinyl alcohol (PVA), or combinations thereof.

[0085] First structure

[0086] The solid electrolyte layer according to an embodiment may include a first structure. The first structure may include a first solid electrolyte layer, a second solid electrolyte layer, and a first interlayer disposed between the first solid electrolyte layer and the second solid electrolyte layer. The first interlayer may include an adhesive and a tackifier.

[0087] By including an adhesive and a tackifier in the first interlayer, the bonding strength between the first solid electrolyte layer and the second solid electrolyte layer can be improved. The adhesive bonding strength of the adhesive can be further enhanced by additionally imparting adhesiveness to the adhesive having bonding strength via the inclusion of a tackifier. The bonding intensity between the first solid electrolyte layer and the second solid electrolyte layer can be improved by including an adhesive and a tackifier in the first interlayer. For example, the peel strength between the first solid electrolyte layer and the second solid electrolyte layer can be improved. Adhesion can be imparted between the first solid electrolyte layer and the second solid electrolyte layer by including an adhesive and a tackifier in the first interlayer. By disposing the first interlayer between the first solid electrolyte layer and the second solid electrolyte layer, the first solid electrolyte layer and the second solid electrolyte layer can be brought into close contact, resulting in a reduction in porosity between them. The interfacial resistance between the first solid electrolyte layer and the second solid electrolyte layer can be reduced. The internal resistance of the solid electrolyte layer including the first structure can be reduced. By imparting enhanced bonding strength and / or adhesion between the first and second solid electrolyte layers via the first interlayer, the viscoelasticity and / or resilience of the solid electrolyte layers can be improved. By providing enhanced bonding strength and / or adhesion between the first and second solid electrolyte layers via the first interlayer, the formation of pores, cracks, or electrical disconnections between the first and second solid electrolyte layers during charge and discharge cycles of the solid-state secondary battery can be suppressed. By providing enhanced bonding strength and / or adhesion between the first and second solid electrolyte layers via the first interlayer, volume changes of the solid-state secondary battery during charge and discharge cycles can be more effectively suppressed. By providing enhanced adhesion and / or bonding strength between the first and second solid electrolyte layers via the first interlayer, degradation due to volume changes of the solid-state secondary battery during charge and discharge cycles can be more effectively mitigated. By achieving enhanced adhesion and / or bonding strength between the first and second solid electrolyte layers via the first interlayer, the increase in interfacial resistance and / or internal resistance of the solid electrolyte layers during charge and discharge cycles can be suppressed. Therefore, the charge and discharge characteristics of the solid secondary battery can be enhanced.

[0088] Figure 1 This is a schematic cross-sectional view of a solid electrolyte layer including a first structure according to one embodiment.

[0089] refer to Figure 1 The solid electrolyte layer may include a first structure 31. The first structure 31 may include a first solid electrolyte layer 30a, a second solid electrolyte layer 30b, and an interlayer 40a disposed between the first solid electrolyte layer 30a and the second solid electrolyte layer 30b. The first interlayer 40a may include an adhesive and a tackifier. Sometimes, according to an embodiment, the first structure 31 may represent a solid electrolyte layer.

[0090] For example, the adhesive may be a polymeric adhesive. For example, the tackifier may be a compound. For example, the tackifier may be an oligomer or a polymer. When mixed with the adhesive, the tackifier can enhance the bonding strength of the adhesive. The tackifier can improve the surface tack of the adhesive, thereby increasing the bonding strength between the adhesive and the solid electrolyte particles. Additionally, the tackifier can provide adhesiveness.

[0091] For example, in the first interlayer 40a, the content of the tackifier may be from about 1 part by weight to about 100 parts by weight, from about 1 part by weight to about 50 parts by weight, from about 10 parts by weight to about 40 parts by weight, or from about 15 parts by weight to about 30 parts by weight, based on 100 parts by weight of the adhesive. By keeping the tackifier content within this range, the first interlayer 40a can further increase the adhesion and / or bonding strength between the first solid electrolyte layer 30a and the second solid electrolyte layer 30b. The first structure 31 including the first interlayer 40a can effectively accommodate volume changes during the charge and discharge cycles of the solid secondary battery. The increase in internal resistance of the solid electrolyte layer during the charge and discharge cycles of the solid secondary battery can be suppressed. The charge and discharge characteristics of the solid secondary battery including the solid electrolyte layer can be enhanced. If the content of the tackifier is too low, the increase in adhesion and / or bonding strength of the first interlayer 40a may be minimal. If the content of the tackifier is too high, the adhesion of the first interlayer 40a may actually decrease. The structures of the adhesive and the tackifier can be identified using techniques such as infrared spectroscopy (IR) and nuclear magnetic resonance (NMR), while their contents can be determined using inductively coupled plasma (ICP) analysis.

[0092] For example, in the first interlayer 40a, the loading level of the adhesive and the tackifier may be about 0.1 mg / cm². 2 (approximately 5 mg / cm) 2 Approximately 0.1 mg / cm 2 Approximately 3 mg / cm 2 Approximately 0.1 mg / cm 2 Approximately 2 mg / cm 2 or approximately 0.3 mg / cm 2 Approximately 1 mg / cm 2The load level may refer to the content of dried material comprising adhesives and tackifiers disposed on the first solid electrolyte layer 30a, or on the second solid electrolyte layer 30b, or between the first solid electrolyte layer 30a and the second solid electrolyte layer 30b. By placing the load level of the first interlayer 40a within the aforementioned ranges, the first interlayer 40a may further increase the adhesion and / or bonding strength between the first solid electrolyte layer 30a and the second solid electrolyte layer 30b. The solid electrolyte layer including the first interlayer 40a can more effectively accommodate volume changes during the charge and discharge cycles of the solid secondary battery. The increase in internal resistance of the first structure 31 (solid electrolyte layer) during the charge and discharge cycles of the solid secondary battery can be suppressed. The charge and discharge characteristics of the solid secondary battery including the solid electrolyte layer can be enhanced. The load level may be calculated as the weight of dried adhesives and tackifiers per unit area.

[0093] The first interlayer 40a may be continuously or discontinuously arranged between the first solid electrolyte layer 30a and the second solid electrolyte layer 30b in a direction perpendicular to the thickness of the solid electrolyte layer. The first interlayer 40a being continuously arranged between the first solid electrolyte layer 30a and the second solid electrolyte layer 30b in a direction perpendicular to the thickness of the solid electrolyte layer more effectively increases the bonding strength and / or adhesion between the first solid electrolyte layer 30a and the second solid electrolyte layer 30b.

[0094] Although not shown in the figure, the first interlayer 40a may be discontinuously arranged between the first solid electrolyte layer 30a and the second solid electrolyte layer 30b in a direction perpendicular to the thickness direction of the solid electrolyte layer, thereby more effectively ensuring the ion conduction path between the first solid electrolyte layer 30a and the second solid electrolyte layer 30b.

[0095] The thickness of the interlayer can be, for example, from about 0.01 micrometers to about 10 micrometers. For example, the thickness of the first interlayer 40a can be from about 0.01 micrometers (μm) to about 10 μm, from about 0.1 μm to about 10 μm, from about 0.1 μm to about 5 μm, from about 0.1 μm to about 3 μm, or from about 0.1 μm to about 1 μm. The thickness of the interlayer can be, for example, 50% or less of the thickness of the sub-solid electrolyte layer. For example, the thickness of the first interlayer 40a can be 50% or less, 30% or less, 10% or less, 5% or less, 3% or less, or 1% or less of the thickness of the first solid electrolyte layer 30a. For example, the thickness of the first interlayer 40a can be 50% or less, 30% or less, 10% or less, 5% or less, 3% or less, or 1% or less of the thickness of the second solid electrolyte layer 30b. By making the thickness within these ranges, the first interlayer 40a can further enhance the adhesion and / or bonding strength between the first solid electrolyte layer 30a and the second solid electrolyte layer 30b. The solid electrolyte layer including the first interlayer 40a can more effectively accommodate volume changes during charge and discharge cycles of the solid secondary battery. Increases in the internal resistance of the solid electrolyte layer during charge and discharge cycles of the solid secondary battery can be suppressed. The charge and discharge characteristics of the solid secondary battery including the solid electrolyte layer can be further enhanced. The thicknesses of the first interlayer 40a, the first solid electrolyte layer 30a, and the second solid electrolyte layer 30b can be confirmed using scanning electron microscopy (SEM) or transmission electron microscopy (TEM).

[0096] For example, the first interlayer 40a may further include a solid electrolyte. By further including a solid electrolyte in the first interlayer 40a, the first interlayer 40a may have increased ionic conductivity. By further including a solid electrolyte in the first interlayer 40a, the interfacial resistance between the first solid electrolyte layer 30a and the second solid electrolyte layer 30b can be reduced more effectively. The first interlayer 40a may further include a solid electrolyte, and the solid electrolyte may include, for example, a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a halide-based solid electrolyte, an oxyhalide-based solid electrolyte, or a combination thereof. The first interlayer 40a may further include a solid electrolyte, and the solid electrolyte may be selected from the solid electrolyte used in the first solid electrolyte layer 30a and / or the second solid electrolyte layer 30b. The first interlayer 40a may further include a solid electrolyte, and the solid electrolyte may be the same solid electrolyte as the first solid electrolyte layer 30a and / or the second solid electrolyte layer 30b.

[0097] At least one or two of the multiple sub-solid electrolyte layers are free of a thickener. One or both of the first solid electrolyte layer 30a and the second solid electrolyte layer 30b may be free of a thickener. By omitting a thickener in one or both of the first solid electrolyte layer 30a and the second solid electrolyte layer 30b, an increased ion conduction path can be ensured within the first solid electrolyte layer 30a and / or the second solid electrolyte layer 30b. The first structure 31 may include the first solid electrolyte layer 30a, the second solid electrolyte layer 30b, and a first interlayer 40a disposed between the first solid electrolyte layer and the second solid electrolyte layer. The first interlayer 40a may include an adhesive and a thickener, while the first solid electrolyte layer 30a and the second solid electrolyte layer 30b may be free of a thickener, thereby enabling a further increase in ion conduction paths. The cycle characteristics of a solid-state secondary battery including such a first structure 31 can be improved.

[0098] The first solid electrolyte layer 30a may include a first surface adjacent to the first interlayer 40a and a second surface spaced apart from and opposite to the first surface. The first solid electrolyte layer 30a may be free of a thickener, for example, in the central region between the first and second surfaces. The central region between the first and second surfaces may correspond to, for example, about 40% to about 60% of the total distance between the first and second surfaces. By omitting a thickener in the central region between the first and second surfaces, an enhanced ion conduction path can be ensured within the solid electrolyte layer. This can improve the cycling characteristics of a solid-state secondary battery including the solid electrolyte layer.

[0099] The second solid electrolyte layer 30b may include a first surface adjacent to the first interlayer 40a and a second surface spaced apart from and opposite to the first surface. The second solid electrolyte layer 30b may be free of a thickener, for example, in the central region between the first and second surfaces. The central region between the first and second surfaces may correspond to, for example, approximately 40% to approximately 60% of the total distance between the first and second surfaces. By omitting a thickener in the central region between the first and second surfaces, an enhanced ion conduction path can be ensured within the solid electrolyte layer. This can improve the cycling characteristics of the solid secondary battery including the solid electrolyte layer.

[0100] Alternatively, for example, one or both of the first solid electrolyte layer 30a and the second solid electrolyte layer 30b may include a tackifier. Including a tackifier in one or more of the first solid electrolyte layer 30a and the second solid electrolyte layer 30b can further enhance the adhesion and / or bonding strength of the solid electrolyte layers including the first solid electrolyte layer 30a and the second solid electrolyte layer 30b. The first structure 31 may include the first solid electrolyte layer 30a, the second solid electrolyte layer 30b, and a first interlayer 40a disposed between the first solid electrolyte layer and the second solid electrolyte layer. The first interlayer 40a may include an adhesive and a tackifier. One or both of the first solid electrolyte layer 30a and the second solid electrolyte layer 30b may include a tackifier, thereby further enhancing the structural stability of the solid electrolyte layers. The solid electrolyte layers can more effectively accommodate volume changes during charge and discharge cycles of the solid secondary battery. Increases in the internal resistance of the solid electrolyte layers during charge and discharge cycles of the solid secondary battery can be suppressed. The charge and discharge characteristics of the solid secondary battery including the solid electrolyte layer 30 can be enhanced.

[0101] One or both of the first solid electrolyte layer 30a and the second solid electrolyte layer 30b may include a tackifier. For example, the content of the tackifier in one or both of the first solid electrolyte layer 30a and the second solid electrolyte layer 30b may be from about 1 part by weight to about 100 parts by weight, from about 1 part by weight to about 50 parts by weight, from about 10 parts by weight to about 40 parts by weight, or from about 15 parts by weight to about 30 parts by weight, based on 100 parts by weight of the adhesive. By making the tackifier content within these ranges, the adhesion and bonding strength of the first solid electrolyte layer 30a and / or the second solid electrolyte layer 30b can be further increased. The first structure 31 including the first solid electrolyte layer 30a and the second solid electrolyte layer 30b can effectively accommodate volume changes during charge and discharge cycles of the solid secondary battery. Increases in the internal resistance of the solid electrolyte layer 30 during charge and discharge cycles of the solid secondary battery can be suppressed. The charge and discharge characteristics of the solid secondary battery including the solid electrolyte layer can be enhanced. When the content of the tackifier is too low, the peel strength of the first solid electrolyte layer 30a and / or the second solid electrolyte layer 30b may be reduced. When the content of the tackifier is too high, the adhesion of the first solid electrolyte layer 30a and the second solid electrolyte layer 30b may actually be reduced. The structure of the adhesive and the tackifier can be identified using techniques such as IR and NMR, while their content can be determined using ICP analysis.

[0102] The content of the tackifier in the first interlayer 40a may be higher than the content of the tackifier in the first solid electrolyte layer 30a. The content of the tackifier in the first interlayer 40a may be higher than the content of the tackifier in the second solid electrolyte layer 30b. For example, compared to the content of the tackifier in the first solid electrolyte layer 30a, the content of the tackifier in the first interlayer 40a may be more than 100%, 150% or more, 200% or more, or 500% or more. For example, compared to the content of the tackifier in the second solid electrolyte layer 30b, the content of the tackifier in the first interlayer 40a may be more than 100%, 150% or more, 200% or more, or 500% or more.

[0103] The structural stability of the solid electrolyte layer can be further improved by increasing the content of the thickener in the first interlayer 40a compared to that in the first solid electrolyte layer 30a and / or the second solid electrolyte layer 30b. Furthermore, by increasing the content of the thickener in the first interlayer 40a compared to that in the first solid electrolyte layer 30a and / or the second solid electrolyte layer 30b, the increase in internal resistance of the solid electrolyte layer during charge and discharge cycles of the solid secondary battery can be more effectively suppressed. This improves the cycle characteristics of the solid secondary battery including the solid electrolyte layer.

[0104] The first solid electrolyte layer 30a may include a first surface adjacent to the first interlayer 40a and a second surface spaced from and opposite to the first surface. The tackifier content in the region adjacent to the first surface may be higher than in the region adjacent to the second surface. The region adjacent to the first surface may correspond to, for example, within 10% of the total distance between the first and second surfaces from the first surface. The region adjacent to the second surface may correspond to, for example, within 10% of the total distance between the first and second surfaces from the second surface. By making the tackifier content in the region adjacent to the first surface of the first solid electrolyte layer 30a higher than in the region adjacent to the second surface, the increase in internal resistance of the solid electrolyte layer during charge and discharge cycles of the solid secondary battery can be more effectively suppressed. The cycling characteristics of a solid secondary battery including such a solid electrolyte layer can be improved.

[0105] The second solid electrolyte layer 30b may include a first surface adjacent to the first interlayer 40a and a second surface spaced from and opposite to the first surface. The tackifier content in the region adjacent to the first surface may be higher than in the region adjacent to the second surface. The region adjacent to the first surface may correspond to, for example, within 10% of the total distance between the first and second surfaces from the first surface. The region adjacent to the second surface may correspond to, for example, within 10% of the total distance between the first and second surfaces from the second surface. By making the tackifier content in the region adjacent to the first surface of the second solid electrolyte layer 30b higher than in the region adjacent to the second surface, the increase in internal resistance of the solid electrolyte layer during charge and discharge cycles of the solid secondary battery can be more effectively suppressed. The cycling characteristics of the solid secondary battery including the solid electrolyte layer can be improved.

[0106] The thicknesses of the first solid electrolyte layer 30a and the second solid electrolyte layer 30b can each independently be approximately 5 μm to approximately 200 μm, approximately 10 μm to approximately 150 μm, approximately 10 μm to approximately 100 μm, approximately 30 μm to approximately 100 μm, or approximately 50 μm to approximately 100 μm. By making the thicknesses of the first solid electrolyte layer 30a and the second solid electrolyte layer 30b within these ranges, the solid electrolyte layer including the first solid electrolyte layer 30a and the second solid electrolyte layer 30b can more effectively adapt to volume changes during charge and discharge cycles of the solid secondary battery. The increase in internal resistance of the solid electrolyte layer during charge and discharge cycles of the solid secondary battery can be suppressed. The charge and discharge characteristics of the solid secondary battery including the solid electrolyte layer can be further enhanced. The thicknesses of the first solid electrolyte layer 30a and the second solid electrolyte layer 30b can be confirmed using SEM or TEM.

[0107] The first solid electrolyte layer 30a and the second solid electrolyte layer 30b may independently include solid electrolytes. For example, the solid electrolyte may include sulfide-based solid electrolytes, oxide-based solid electrolytes, halide-based solid electrolytes, oxyhalide-based solid electrolytes, or combinations thereof.

[0108] For example, the sulfide-based solid electrolyte may include lithium sulfide, silicon sulfide, phosphorus sulfide, boron sulfide, or combinations thereof. The sulfide-based solid electrolyte particles may include Li₂S, P₂S₅, SiS₂, GeS₂, B₂S₃, or combinations thereof. The sulfide-based solid electrolyte particles may be Li₂S or P₂S₅. It is known that sulfide-based solid electrolyte particles have higher lithium-ion conductivity compared to other inorganic compounds. For example, the sulfide-based solid electrolyte may include Li₂S and P₂S₅. When the sulfide solid electrolyte material constituting the solid electrolyte includes Li₂S-P₂S₅, the mixing molar ratio of Li₂S to P₂S₅ may range from, for example, about 50:50 to about 90:10. The sulfide-based solid electrolyte may also include an inorganic solid electrolyte prepared by: mixing Li₃PO₄, halogens, halogen compounds, Li₂S, and Li₂S₅. 2+2x Zn 1-x GeO4 (“LISICON”), Li 3+y PO 4-x N x (“LIPON”), Li 3.25 Ge 0.25 P 0.75 S4 (“ThioLISICON”) and Li2O-Al2O3-TiO2-P2O5 (“LATP”) are added to Li2S-P2S5, SiS2, GeS2, B2S3, or combinations thereof.

[0109] Non-limiting examples of the sulfide solid electrolyte materials include: Li₂S-P₂S₅; Li₂S-P₂S₅-LiX (where X is a halogen element); Li₂S-P₂S₅-Li₂O; Li₂S-P₂S₅-Li₂O-LiI; Li₂S-SiS₂; Li₂S-SiS₂-LiI; Li₂S-SiS₂-LiBr; Li₂S-SiS₂-LiCl; Li₂S-SiS₂-B₂S₃-LiI; Li₂S-SiS₂-P₂S₅-LiI; Li₂S-B₂S₃; Li₂S-P₂S₅-Z m S n (m and n are positive numbers, and Z is Ge, Zn, or Ga); Li2S-GeS2; Li2S-SiS2-Li3PO4; and Li2S-SiS2-Li p MO q (Where p and q are positive numbers, and M is P, Si, Ge, B, Al, Ga, or In). In this regard, the sulfide-based solid electrolyte material can be prepared by treating the starting materials (e.g., Li₂S, P₂S₅, etc.) of the sulfide-based solid electrolyte by methods such as melt quenching or mechanical grinding. Furthermore, a calcination process can be performed after the above treatment.

[0110] For example, the sulfide-based solid electrolyte may include a sulfide-germanium ore type solid electrolyte represented by formula A:

[0111] Formula A

[0112] Li + 12-n-x A n+ X 2- 6-x Y - x

[0113] Where A is P, As, Ge, Ga, Sb, Si, Sn, Al, In, Ti, V, Nb, or Ta; X is S, Se, or Te; Y is Cl, Br, I, F, CN, OCN, SCN, or N3; and 1 ≤ n ≤ 5 and 0 ≤ x ≤ 2. For example, the sulfide-based solid electrolyte may be a sulfide-germanium ore type compound comprising at least one or more of the following: Li 7-x PS 6-x Cl x , 0≤x≤2; Li 7-x PS 6-x Br x , 0≤x≤2; or Li 7-x PS 6-x I x , 0≤x≤2. For example, the sulfide-based solid electrolyte may be a sulfide-germanium ore type compound including at least one or more of the following: Li6PS5Cl, Li6PS5Br, or Li6PS5I.

[0114] For example, the oxide-based solid electrolyte may include garnet-type solid electrolytes, nasicon-type solid electrolytes, LISICON-type solid electrolytes, perovskite-type solid electrolytes, LiPON-type solid electrolytes, amorphous (glass) solid electrolytes, or metal oxides. The solid electrolyte may be manufactured using, for example, sintering methods.

[0115] Garnet-type solid electrolytes may include lithium lanthanum zirconium oxide (LLZO), derived from the formula Li 3+x La y M z O 12 The expression represents (1≤x≤10, 2≤y≤4, 1≤z≤3, where M is Zr, Ga, W, Nb, Ta, Al, or a combination thereof). Examples may include Li7La3Zr2O. 12 and Li 3+x La3Zr 2-a M a O 12(LLZO doped with M, where M = Ga, W, Nb, Ta, Al, or a combination thereof, 1 ≤ x ≤ 10, 0 < a < 2).

[0116] The Nasicon-type solid electrolyte may include Li 1+x Al x M 2-x (PO4)3 (0 < x < 2, where M = Zr, Ti, Ge, or a combination thereof, LAMP type), Li 1+x Al x Ti 2-x (PO4)3 (0 < x < 1) (lithium aluminum titanium phosphate doped with Ti (LATP)), Li 1.3 Al 0.3 Ti 1.7 (PO4)3 (LATP doped with excessive lithium), Li 1+x Al x Ge 2-x (PO4)3 (0 < x < 1) (lithium aluminum germanium phosphate (LAGP)), or LiZr2(PO4)3 (lithium zirconium phosphate (LZP)).

[0117] The LISCON-type solid electrolyte may be represented by xLi3AO4-(1 - x)Li4BO4 (where A is P, As, or V, and B is Si, Ge, or Ti), and may include a solid solution oxide, which includes Li 14 Zn(GeO4)4, Li 10 GeP2O 12 (LGPO), Li 3.5 Si 0.5 P 0.5 O4, and Li 10.42 Si(Ge) 1.5 P 1.5 Cl 0.08 O 11.92 .

[0118] The perovskite-type solid electrolyte may include lanthanum lithium titanate (LLTO), represented by Li 3x La 2 / 3-x □ 1 / 3-2x TiO3 (0 < x < 0.16), where □ represents the A-site vacancy. An example of the perovskite-type solid electrolyte is Li 1 / 8 La 5 / 8 TiO3.

[0119] The LiPON-type solid electrolyte may include lithium phosphorus oxynitride (LiPON), such as Li 2.8 PO 3.3 N 0.46 .

[0120] Amorphous (glass) solid electrolytes include Li2O-B2O3-SiO2, Li2O-B2O3-P2O5, Li3BO3-Li2SO4, or Li3BO3-Li2CO3.

[0121] Metal oxide solid electrolytes may include: HfO2, SrTiO3, SnO2, CeO2, Na2O, MgO, NiO, CaO, BaO, ZnO, ZrO2, Y2O3, Al2O3, TiO2, SiO2, Li3PO4, Li2O, LiOH, Li2CO3, and LiAlO2.

[0122] Oxide-based solid electrolytes may include Li 1+x+y Al x Ti 2-x Si y P 3-y O 12 (0 <x<2、0≤y<3)、BaTiO3、Pb(Zr,Ti)O3 (PZT)、Pb 1-x La x Zr 1-y Ti y O3 (PLZT) (0≤x<1, 0≤y<1), Pb(Mg 1 / 3 Nb 2 / 3 O3-PbTiO3 (PMN-PT), Li x Ti y (PO4)3 (0 <x<2、0<y<3)、Li x Al y Ti z (PO4)3 (0 <x<2、0<y<1、0<z<3)、Li 1+x+y (Al,Ga) x (Ti,Ge) 2-x Si y P 3-y O 12 (0≤x≤1, 0≤y≤1), Li x La y TiO3 (0 <x<2、0<y<3)、Li2O-Al2O3-SiO2-P2O5-TiO2-GeO2、Li 3+x La3M2O 12 (M = Te, Nb, or Zr, x = integers from 1 to 10).

[0123] For example, the solid electrolyte layer may be a self-supporting (self-standing) membrane. A self-supporting membrane is a membrane that can maintain its shape without a support. For example, the self-supporting membrane can be separated from the support and used in lamination processes for electrode manufacturing or solid-state secondary battery manufacturing. In addition, the self-supporting membrane can also facilitate the implementation of various manufacturing processes for electrodes and / or all-solid-state secondary batteries.

[0124] Figure 2 This is a schematic cross-sectional view of a solid electrolyte layer including a first structure 31 according to another embodiment.

[0125] refer to Figure 2 The solid electrolyte layer may include a first structure 31. The first structure 31 may include a first interlayer 40a, a first solid electrolyte layer 30a, and a second solid electrolyte layer 30b, and the first structure 31 may include a top surface and a bottom surface opposite to the top surface. The first structure 31 may further include, for example, a second interlayer 40b disposed on the top surface and / or a third interlayer 40c disposed on the bottom surface. The first interlayer 40a, the second interlayer 40b, and the third interlayer 40c may independently include an adhesive and a tackifier. Although not shown in the figures, the second interlayer 40b or the third interlayer 40c may be omitted. By further including a second interlayer 40b and / or a third interlayer 40c in the solid electrolyte layer, the adhesion and / or bonding strength between the solid electrolyte layer and the positive electrode and / or between the solid electrolyte layer and the negative electrode can be improved. By introducing such a solid electrolyte layer into the solid secondary battery, the increase in internal resistance during charge and discharge cycles can be more effectively suppressed. It can improve the cycle characteristics of solid secondary batteries that include the solid electrolyte layer.

[0126] refer to Figure 1 and 2 The first interlayer 40a, the second interlayer 40b, and the third interlayer 40c include adhesives and tackifiers. The first solid electrolyte layer 30a and the second solid electrolyte layer 30b may optionally include adhesives and tackifiers.

[0127] Second structure

[0128] The solid electrolyte layer according to an embodiment may include a second structure. The second structure may include a third solid electrolyte layer and a fourth solid electrolyte layer. One or more of the third solid electrolyte layer and the fourth solid electrolyte layer may include an adhesive and a tackifier.

[0129] By including an adhesive and a tackifier in one or more of the third and fourth solid electrolyte layers of the second structure, the bonding strength between the solid electrolyte particles constituting the one or more solid electrolyte layers can be improved. Furthermore, in a solid-state secondary battery employing a solid electrolyte layer including the second structure, the bonding strength between the solid electrolyte layer and the positive electrode and / or between the solid electrolyte layer and the negative electrode can be improved. By including an adhesive and a tackifier in one or more of the third and fourth solid electrolyte layers, adhesion can be imparted between the particles constituting the solid electrolyte layer. By bringing the solid electrolyte particles in the solid electrolyte layer into close contact, the voids between the particles can be reduced. The interfacial resistance between the solid electrolyte particles constituting the solid electrolyte layer can be reduced. The internal resistance of the solid electrolyte layer including the second structure can be reduced. By possessing enhanced bonding strength in one or more of the third and fourth solid electrolyte layers, the viscoelasticity and / or resilience of the solid electrolyte layer comprising them can be improved. By providing enhanced bonding strength and / or adhesion in one or both of the third and fourth solid electrolyte layers, the formation of voids, cracks, or electrical disconnections in the layers can be effectively suppressed during charge and discharge cycles of the solid-state secondary battery. By providing enhanced bonding strength and / or adhesion in one or more of the third and fourth solid electrolyte layers, volume changes of the solid-state secondary battery during charge and discharge cycles can be more effectively suppressed. By having enhanced adhesion and / or bonding strength in one or both of the third and fourth solid electrolyte layers, degradation due to volume changes of the solid-state secondary battery during charge and discharge cycles can be more effectively mitigated. By having enhanced adhesion and / or bonding strength in one or both of the third and fourth solid electrolyte layers, the increase in interfacial resistance and / or internal resistance of the solid electrolyte layers during charge and discharge cycles can be suppressed. Therefore, the charge and discharge characteristics of the solid-state secondary battery can be enhanced.

[0130] Figure 3 This is a schematic cross-sectional view of a solid electrolyte layer including a second structure according to one embodiment.

[0131] refer to Figure 3 The solid electrolyte layer may include a second structure 32. The second structure 32 may include a third solid electrolyte layer 30c and a fourth solid electrolyte layer 30d. One or more of the third solid electrolyte layer 30c and the fourth solid electrolyte layer 30d may include an adhesive and a tackifier.

[0132] For example, the content of the tackifier in the third solid electrolyte layer 30c and the fourth solid electrolyte layer 30d can be independently from about 1 part by weight to about 100 parts by weight, about 1 part by weight to about 50 parts by weight, about 10 parts by weight to about 40 parts by weight, or about 15 parts by weight to about 30 parts by weight, based on 100 parts by weight of the adhesive. By keeping the tackifier content within this range, the adhesion and / or bonding strength of the third solid electrolyte layer 30c and the fourth solid electrolyte layer 30d can be further increased. The solid electrolyte layer including the third solid electrolyte layer 30c and the fourth solid electrolyte layer 30d can effectively accommodate volume changes during the charge and discharge cycles of the solid secondary battery. The increase in the internal resistance of the solid electrolyte layer during the charge and discharge cycles of the solid secondary battery can be suppressed. The charge and discharge characteristics of the solid secondary battery including the solid electrolyte layer can be enhanced. If the content of the tackifier is too low, the peel strength of the third solid electrolyte layer 30c and the fourth solid electrolyte layer 30d can be reduced. If the content of the tackifier is too high, the adhesion of the third solid electrolyte layer 30c and the fourth solid electrolyte layer 30d can actually be reduced. The structures of the adhesive and the tackifier can be identified using techniques such as IR and NMR, while their contents can be determined using ICP analysis.

[0133] The thicknesses of the third solid electrolyte layer 30c and the fourth solid electrolyte layer 30d can each independently be approximately 5 μm to approximately 200 μm, approximately 10 μm to approximately 150 μm, approximately 10 μm to approximately 100 μm, approximately 30 μm to approximately 100 μm, or approximately 50 μm to approximately 100 μm. By making the thicknesses of the third solid electrolyte layer 30c and the fourth solid electrolyte layer 30d within these ranges, the solid electrolyte layer including the third solid electrolyte layer 30c and the fourth solid electrolyte layer 30d can more effectively adapt to volume changes during charge and discharge cycles of the solid secondary battery. The increase in internal resistance of the solid electrolyte layer during charge and discharge cycles of the solid secondary battery can be suppressed. The charge and discharge characteristics of the solid secondary battery including the solid electrolyte layer can be further enhanced. The thicknesses of the third solid electrolyte layer 30c and the fourth solid electrolyte layer 30d can be confirmed using SEM or TEM.

[0134] The third solid electrolyte layer 30c and the fourth solid electrolyte layer 30d may include solid electrolytes. For example, the solid electrolytes may include sulfide-based solid electrolytes, oxide-based solid electrolytes, halide-based solid electrolytes, oxyhalide-based solid electrolytes, or combinations thereof. The solid electrolyte may be selected from the solid electrolyte used in the first structure 31 described above.

[0135] Figure 4This is a schematic cross-sectional view of a solid electrolyte layer including a second structure 32 according to another embodiment.

[0136] refer to Figure 4 The solid electrolyte layer may include a second structure 32. The second structure 32 may include a third solid electrolyte layer 30c and a fourth solid electrolyte layer 30d, and the second structure 32 may include a top surface and a bottom surface opposite the top surface. For example, the second structure 32 may further include a second interlayer 40b disposed on the top surface and / or a third interlayer 40c disposed on the bottom surface. The second interlayer 40b and the third interlayer 40c may independently include an adhesive and a tackifier. Although not shown in the figures, the second interlayer 40b or the third interlayer 40c may be omitted. By further including a second interlayer 40b and / or a third interlayer 40c in the solid electrolyte layer including the second structure 32, the adhesion and / or bonding strength between the solid electrolyte layer and the positive electrode and / or between the solid electrolyte layer and the negative electrode can be improved. By introducing such a solid electrolyte layer into the solid secondary battery, the increase in internal resistance during charge and discharge cycles can be more effectively suppressed. The cycle characteristics of the solid secondary battery including the solid electrolyte layer can be improved.

[0137] refer to Figure 3 and 4 One or both of the third solid electrolyte layer 30c and the fourth solid electrolyte layer 30d may include an adhesive and a tackifier. The adhesive and the tackifier included in the third solid electrolyte layer 30c and the fourth solid electrolyte layer 30d may be selected from the adhesives and tackifiers used in the first structure 31 described above.

[0138] Third structure

[0139] The solid electrolyte layer according to the embodiment may include a third structure. The third structure may include a fifth solid electrolyte layer. The fifth solid electrolyte layer may include an adhesive and a tackifier.

[0140] By including a binder and a tackifier in the fifth solid electrolyte layer of the third structure, the bonding strength between the solid electrolyte particles constituting the fifth solid electrolyte layer can be improved. Furthermore, in a solid-state battery employing a solid electrolyte layer including the third structure, the bonding strength between the solid electrolyte layer and the positive electrode and / or between the solid electrolyte layer and the negative electrode can be improved. Including a binder and a tackifier in the fifth solid electrolyte layer imparts adhesion between the particles constituting the solid electrolyte layer. By bringing the solid electrolyte particles in the fifth solid electrolyte layer into close contact, voids between the particles can be reduced. The interfacial resistance between the solid electrolyte particles constituting the solid electrolyte layer can be reduced. The internal resistance of the solid electrolyte layer including the third structure can be reduced. By possessing enhanced bonding strength in the fifth solid electrolyte layer, the viscoelasticity and / or resilience of the solid electrolyte layer comprising them can be improved. By providing improved bonding strength and / or adhesion in the fifth solid electrolyte layer, the occurrence of voids, cracks, or electrical disconnections in the fifth solid electrolyte layer during charge and discharge cycles of the solid secondary battery can be suppressed. By providing enhanced bonding strength and / or adhesion in the fifth solid electrolyte layer, volume changes in the solid secondary battery during charge and discharge cycles can be more effectively suppressed. Enhanced bonding strength and / or adhesion in the fifth solid electrolyte layer can also more effectively mitigate degradation caused by volume changes in the solid secondary battery during charge and discharge cycles. Furthermore, enhanced bonding strength and / or adhesion in the fifth solid electrolyte layer can suppress increases in interfacial resistance and / or internal resistance of the solid electrolyte layer during charge and discharge cycles. Therefore, the charge and discharge characteristics of the solid secondary battery can be enhanced.

[0141] Figure 5 This is a schematic cross-sectional view of a solid electrolyte layer including a third structure 33 according to one embodiment.

[0142] refer to Figure 5 The solid electrolyte layer may include a third structure 33. The third structure 33 may include a fifth solid electrolyte layer 30e. The fifth solid electrolyte layer 30e may include an adhesive and a tackifier.

[0143] For example, in the fifth solid electrolyte layer 30e, the content of the tackifier can be independently from about 1 part by weight to about 100 parts by weight, about 1 part by weight to about 50 parts by weight, about 10 parts by weight to about 40 parts by weight, or about 15 parts by weight to about 30 parts by weight, based on 100 parts by weight of the adhesive. By keeping the tackifier content within this range, the adhesiveness and / or bonding strength of the fifth solid electrolyte layer 30e can be further increased. The solid electrolyte layer including the fifth solid electrolyte layer 30e can effectively accommodate volume changes during the charge and discharge cycles of the solid secondary battery. The increase in the internal resistance of the solid electrolyte layer during the charge and discharge cycles of the solid secondary battery can be suppressed. Charge and discharge characteristics can be enhanced. If the tackifier content is too low, the peel strength of the fifth solid electrolyte layer 30e can be reduced. If the tackifier content is too high, the adhesiveness of the fifth solid electrolyte layer 30e can actually be reduced. The structures of the adhesive and the tackifier can be identified using techniques such as IR and NMR, while their contents can be determined using ICP analysis.

[0144] The thickness of the fifth solid electrolyte layer 30e can be independently from about 5 μm to about 200 μm, about 10 μm to about 150 μm, about 10 μm to about 100 μm, about 30 μm to about 100 μm, or about 50 μm to about 100 μm. By making the thickness of the fifth solid electrolyte layer 30e within these ranges, the solid electrolyte layer including the fifth solid electrolyte layer 30e can more effectively adapt to volume changes during the charge and discharge cycles of the solid secondary battery. The increase in the internal resistance of the solid electrolyte layer during the charge and discharge cycles of the solid secondary battery can be suppressed. The charge and discharge characteristics of the solid secondary battery including the solid electrolyte layer can be further enhanced. The thickness of the fifth solid electrolyte layer 30e can be confirmed using SEM or TEM.

[0145] The fifth solid electrolyte layer 30e may include a solid electrolyte. For example, the solid electrolyte may include a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a halide-based solid electrolyte, an oxyhalide-based solid electrolyte, or a combination thereof. The solid electrolyte may be selected from the solid electrolyte used in the first structure 31 described above.

[0146] Figure 6 This is a schematic cross-sectional view of a solid electrolyte layer including a third structure 33 according to another embodiment.

[0147] refer to Figure 6The solid electrolyte layer may include a third structure 33. The third structure 33 may include a fifth solid electrolyte layer 30e, and the third structure 33 includes a top surface and a bottom surface opposite the top surface. For example, the third structure 33 may further include a second interlayer 40b disposed on the top surface and / or a third interlayer 40c disposed on the bottom surface. The second interlayer 40b and the third interlayer 40c may each independently include an adhesive and a tackifier. Although not shown in the figures, the second interlayer 40b or the third interlayer 40c may be omitted. By further including a second interlayer 40b and / or a third interlayer 40c in the solid electrolyte layer including the third structure 33, the adhesion and / or bonding strength between the solid electrolyte layer and the positive electrode and / or between the solid electrolyte layer and the negative electrode can be improved. By introducing such a solid electrolyte layer into the solid secondary battery, the increase in internal resistance during charge and discharge cycles can be more effectively suppressed. The cycle characteristics of the solid secondary battery including the solid electrolyte layer can be improved.

[0148] refer to Figure 5 and 6 The fifth solid electrolyte layer 30e may include an adhesive and a tackifier. The adhesive and tackifier included in the fifth solid electrolyte layer 30e may be selected from the adhesives and tackifiers used in the first structure 31 described above.

[0149] solid-state batteries

[0150] By including a solid electrolyte layer in a solid-state battery, the internal resistance of the solid-state battery can be reduced, and the charging and discharging characteristics of the solid-state battery can be enhanced.

[0151] Figures 7 to 12 This is a schematic diagram of a solid-state battery according to an embodiment. The solid-state battery 50 may include, for example, a positive electrode layer 10 including a positive electrode active material layer 12 disposed on a positive electrode current collector 11; a negative electrode layer 20 including a negative electrode active material layer 22 disposed on a negative electrode current collector 21; and a solid electrolyte layer disposed between the positive electrode layer 10 and the negative electrode layer 20.

[0152] The solid-state battery can be prepared as follows.

[0153] First, the positive electrode 10 is prepared. The positive electrode 10 can be prepared by forming a positive electrode active material layer 12 containing positive electrode active material on the positive electrode current collector 11.

[0154] The positive electrode active material layer 12 can be prepared using vapor-phase, solid-phase, or liquid-phase methods. Vapor-phase deposition methods may include, but are not limited to, pulsed laser deposition (PLD), sputtering deposition, chemical vapor deposition (CVD), or any other applicable method in the relevant technical field. Solid-phase methods may include, but are not limited to, sintering, powder pressing, or any other applicable method in the relevant technical field. Liquid-phase methods may include, but are not limited to, sol-gel, doctor blade, screen printing, slurry casting, or any other applicable method in the relevant technical field.

[0155] For example, the positive electrode active material layer 12 can be prepared as follows. A positive electrode active material composition can be prepared by mixing a positive electrode active material, a conductive agent, a binder, and a solvent. The positive electrode active material composition can be directly coated onto the positive electrode current collector 11 and dried to form the positive electrode 10. Alternatively, the positive electrode active material composition can be cast onto a separate substrate to form a layer, and then the film can be peeled off and laminated onto the positive electrode current collector 11 to manufacture the positive electrode 10. Additionally, the positive electrode active material composition can be prepared in the form of an electrode ink containing an excess of solvent and printed onto the positive electrode current collector 11 using an inkjet or gravure printing method to manufacture the positive electrode 10. The printing method is not limited to the methods described above, and any conventional coating or printing method suitable for the art can be used.

[0156] The positive electrode active material layer 12 may include a positive electrode active material.

[0157] The positive electrode active material can be any material commonly used in lithium batteries, without limitation. For example, the positive electrode active material can be a lithium transition metal oxide, a transition metal sulfide, etc. For example, the lithium transition metal oxide can be one or more composite oxides of lithium and metals selected from cobalt, manganese, nickel, and combinations thereof. For example, the positive electrode active material may include a compound represented by the following chemical formula: Li a A 1-b B' b D2 (where 0.90≤a≤1 and 0≤b≤0.5); Li a E 1-b B' b O 2-c D c (where 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05); LiE 2-b B' b O 4-c D c (where 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05); Li a Ni 1-b-c Co b B' c D α(where 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α≤2); Li a Ni 1-b- c Co b B' c O 2-α F' α (where 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α<2); Li a Ni 1-b-c Mn b B' c D α (where 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α≤2); Li a Ni 1-b-c Mn b B' c O 2-α' F' α (where 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05, 0<α<2); Li a Ni b E c G d O2 (where 0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5, 0.001≤d≤0.1); Li a Ni b Co c Mn d G e O2 (where 0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0.001≤e≤0.1); Li a NiG b O2 (where 0.90≤a≤1, 0.001≤b≤0.1); Li a CoG b O2 (where 0.90≤a≤1, 0.001≤b≤0.1); Li a MnG b O2 (where 0.90≤a≤1, 0.001≤b≤0.1); Li a Mn2G b O4 (where 0.90≤a≤1, 0.001≤b≤0.1); QO2; QS2; LiQS2; V2O5; LiV2O5; LiI'O2; LiNiVO4; Li (3-f) J2(PO4)3 (where 0≤f≤2); Li (3-f)Fe2(PO4)3 (where 0 ≤ f ≤ 2); and LiFePO4. In the above formula, A is Ni, Co, Mn, or a combination thereof; B' is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements, or a combination thereof; D is O, F, S, P, or a combination thereof; E is Co, Mn, or a combination thereof; F' is F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; Q is Ti, Mo, Mn, or a combination thereof; I' is Cr, V, Fe, Sc, Y, or a combination thereof; and J is V, Cr, Mn, Co, Ni, Cu, or a combination thereof. For example, the positive electrode active material may include LiCoO2, LiMn x O 2x (x = 1, 2), LiNi 1-x Mn x O2 (0 < x < 1), LiNi 1-x- y Co x Mn y O2 (0 ≤ x ≤ 0.5, 0 ≤ y ≤ 0.5), LiFePO4, TiS2, FeS2, TiS3, and FeS3.

[0158] For example, the positive electrode active material may include lithium transition metal oxides represented by Formulas 1 to 8:

[0159] Formula 1

[0160] Li a Ni x Co y M z O 2-b A b

[0161] Where in Formula 1,

[0162] 1.0 ≤ a ≤ 1.2, 0 ≤ b ≤ 0.2, 0.8 ≤ x < 1, 0 ≤ y ≤ 0.3, 0 < z ≤ 0.3, and x + y + z = 1,

[0163] M is manganese (Mn), niobium (Nb), vanadium (V), magnesium (Mg), gallium (Ga), silicon (Si), tungsten (W), molybdenum (Mo), iron (Fe), chromium (Cr), copper (Cu), zinc (Zn), titanium (Ti), aluminum (Al), boron (B), or a combination thereof,

[0164] A is F, S, Cl, Br, or a combination thereof,

[0165] Formula 2

[0166] LiNi x Co y Mnz O2

[0167] Formula 3

[0168] LiNi x Co y Al z O2

[0169] In Formulas 2 to 3, 0.8 ≤ x ≤ 0.95, 0 ≤ y ≤ 0.2, 0 < z ≤ 0.2, and x + y + z = 1

[0170] Formula 4

[0171] LiNi x Co y Mn z Al w O2

[0172] In Formula 4, 0.8 ≤ x ≤ 0.95, 0 ≤ y ≤ 0.2, 0 < z ≤ 0.2, 0 < w ≤ 0.2, and x + y + z + w = 1

[0173] Formula 5

[0174] Li a Co x M y O 2-b A b

[0175] In Formula 5, 1.0 ≤ a ≤ 1.2, 0 ≤ b ≤ 0.2, 0.9 ≤ x ≤ 1, 0 ≤ y ≤ 0.1, and x + y = 1,

[0176] M is manganese (Mn), niobium (Nb), vanadium (V), magnesium (Mg), gallium (Ga), silicon (Si), tungsten (W), molybdenum (Mo), iron (Fe), chromium (Cr), copper (Cu), zinc (Zn), titanium (Ti), aluminum (Al), boron (B), or a combination thereof,

[0177] A is F, S, Cl, Br, or a combination thereof,

[0178] Formula 6

[0179] Li a Ni x Mn y M' z O 2-b A b

[0180] In Formula 6,

[0181] 1.0 ≤ a ≤ 1.2, 0 ≤ b ≤ 0.2, 0 < x ≤ 0.3, 0.5 ≤ y < 1, 0 < z ≤ 0.3, and x + y + z = 1,

[0182] M' is cobalt (Co), niobium (Nb), vanadium (V), magnesium (Mg), gallium (Ga), silicon (Si), tungsten (W), molybdenum (Mo), iron (Fe), chromium (Cr), copper (Cu), zinc (Zn), titanium (Ti), aluminum (Al), boron (B), or a combination thereof.

[0183] A is F, S, Cl, Br, or a combination thereof.

[0184] Formula 7

[0185] Li a M1 x M2 y PO 4-b X b

[0186] In Equation 7, 0.90 ≤ a ≤ 1.1, 0 ≤ x ≤ 0.9, 0 ≤ y ≤ 0.5, 0.9 <x+y<1.1,0≤b≤2,

[0187] M1 is chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zirconium (Zr), or a combination thereof.

[0188] M2 is magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), titanium (Ti), zinc (Zn), boron (B), niobium (Nb), gallium (Ga), indium (In), molybdenum (Mo), tungsten (W), aluminum (Al), silicon (Si), chromium (Cr), vanadium (V), scandium (Sc), yttrium (Y), or combinations thereof, and

[0189] X is O, F, S, P, or a combination thereof.

[0190] Formula 8

[0191] Li a M3 z PO4

[0192] In Equation 8, 0.90 ≤ a ≤ 1.1, 0.9 ≤ z ≤ 1.1, and

[0193] M3 is chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zirconium (Zr), or a combination thereof.

[0194] The positive electrode active material may be covered by a coating layer. The coating layer may be any layer known as a coating layer for positive electrode active materials used in multilayer ceramic batteries. For example, the coating layer may be Li2O-ZrO2 (LZO).

[0195] For example, the particle size of the positive electrode active material may range from about 0.1 μm to about 20 μm, about 0.5 μm to about 10 μm, or about 1 μm to about 5 μm. For example, the positive electrode active material may be a single crystal particle or a polycrystalline particle.

[0196] For example, the positive electrode active material may be in the form of a true sphere, an ellipsoid, or other granular shape. The particle size of the positive electrode active material is not particularly limited and falls within the range suitable for positive electrode active materials used in conventional all-solid-state batteries. The content of the positive electrode active material in the positive electrode active material layer 12 is not particularly limited and falls within the range typically used in positive electrode active material layers 12 in solid-state batteries. The content of the positive electrode active material included in the positive electrode active material layer 12 may be approximately 80% to approximately 99% by weight, approximately 80% to approximately 95% by weight, or approximately 80% to approximately 90% by weight of the total weight of the positive electrode active material layer 12.

[0197] The positive electrode active material layer 12 may further include a solid electrolyte. The solid electrolyte may be selected from the solid electrolyte used in the solid electrolyte layer 30. For example, the solid electrolyte may include an oxide-based solid electrolyte, a sulfide-based solid electrolyte, an oxyhalide-based solid electrolyte, or a combination thereof. The solid electrolyte content in the positive electrode active material layer 12 may be from about 0.1% to about 20% by weight, from about 1% to about 20% by weight, or from about 10% to about 20% by weight of the total weight of the positive electrode active material layer 12.

[0198] The positive electrode active material layer 12 may further include a conductive material, an adhesive, or a combination thereof.

[0199] For example, the conductive material may include a carbon-based conductive material. For example, the carbon-based conductive material may include carbon black, carbon fiber, graphite, fluorocarbons, or combinations thereof. The carbon black may include acetylene black, Ketjen black, Super P carbon (superconducting carbon black), channel black, furnace black, lamp black, pyrolytic carbon black, or combinations thereof. The graphite may be natural graphite or artificial graphite. In addition to the carbon-based conductive agents described above, the positive electrode active material layer 12 may further include a metal-based conductive agent (metal-based conductive agent), a metal oxide-based conductive agent (metal oxide-based conductive agent), or a polymer-based conductive agent (polymer-based conductive agent). The metal conductive material may include, 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. The content of the conductive agent may be 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, based on 100 parts by weight of the positive electrode active material.

[0200] The adhesive improves the adhesion between the components of the positive electrode active material layer 12 and the adhesion of the positive electrode active material layer 12 to the positive electrode current collector 11. For example, the adhesive may include polyacrylic acid (PAA), polyvinylidene fluoride (PVDF), polyvinyl alcohol (PVA), carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone (PVP), polytetrafluoroethylene, polyethylene (PE), polypropylene (PP), ethylene propylene diene monomer (EPDM), sulfonated EPDM, styrene-butadiene rubber (SBR), fluorinated rubber, copolymers thereof, or combinations thereof. The amount of the adhesive may be 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, based on 100 parts by weight of the positive electrode active material. The adhesive may be omitted.

[0201] For example, the positive electrode current collector 11 may include a metal-based substrate (metal-based substrate) or a carbon-based substrate (carbon-based substrate). The metal-based substrate may include stainless steel, nickel (Ni), aluminum (Al), indium (In), copper (Cu), magnesium (Mg), titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), germanium (Ge), lithium (Li), or alloys thereof, in the form of a porous body, mesh, plate, or foil. For example, the carbon-based substrate may include one-dimensional carbon-based materials such as carbon fibers or carbon nanotubes; two-dimensional carbon-based materials such as graphite or graphene; or combinations thereof. The positive electrode current collector 12 may further include an adhesive. The adhesive may be selected from the adhesives used in the positive electrode active material layer 12. The positive electrode current collector 11 may be omitted.

[0202] Next, a solid electrolyte layer is prepared.

[0203] refer to Figures 7 to 10 A solid electrolyte layer comprising a first structure 31, a solid electrolyte layer comprising a second structure 32, or a solid electrolyte layer comprising a third structure 33 is prepared.

[0204] Next, negative electrode 20 is prepared.

[0205] refer to Figures 7 to 12 The negative electrode 20 may include a negative electrode current collector 21 and a negative electrode active material layer 22 disposed on the negative electrode current collector 21, and the negative electrode active material layer 22 may include, for example, a negative electrode active material and an adhesive.

[0206] For example, the negative electrode active material included in the negative electrode active material layer 22 is in particulate form. For example, the average particle size of the negative electrode active material may be 4 μm or less, 3 μm or less, 2 μm or less, 1 μm or less, or 900 nanometers (nm) or less. For example, the average particle size may also range from about 10 nm to about 4 μm or less, about 10 nm to about 3 μm or less, about 10 nm to about 2 μm or less, about 10 nm to about 1 μm or less, or about 10 nm to about 900 nm or less. By making the average particle size of the negative electrode active material within these ranges, reversible absorption and / or desorption of lithium during charge and discharge cycles can be facilitated. For example, the average particle size of the negative electrode active material can be measured using a laser particle size analyzer as the median diameter (D50).

[0207] For example, the negative electrode active material included in the negative electrode active material layer 22 includes one or more selected from carbon-based negative electrode active materials (carbon-based negative electrode active materials) and metal or quasi-metal negative electrode active materials.

[0208] The carbon-based negative electrode active material is specifically amorphous carbon. Examples of amorphous carbon include carbon black (CB), acetylene black (AB), furnace black (FB), Ketjen black (KB), and graphene. However, it is not limited to these, and any material classified as amorphous carbon in the relevant art can be used. Amorphous carbon refers to carbon materials that are non-crystalline or have very low crystallinity, distinguishing them from crystalline carbon or graphitic carbon.

[0209] The metallic or quasi-metallic anode active material may include, but is not limited to, at least one or more of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), or zinc (Zn), and may use any metallic or quasi-metallic anode active material that forms an alloy or compound with lithium in the relevant art. For example, nickel (Ni) does not form an alloy with lithium and is therefore not a metallic anode active material.

[0210] The negative electrode active material layer 22 may comprise a single type of negative electrode active material or a mixture of multiple different negative electrode active materials. For example, the negative electrode active material layer 22 may comprise only amorphous carbon or at least one or more of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), or zinc (Zn). Alternatively, the negative electrode active material layer 22 may comprise at least one or more of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), or zinc (Zn) in combination with amorphous carbon. For example, the mixing ratio (by weight) of amorphous carbon to metal in the mixture may be about 10:1 to about 1:2, about 5:1 to about 1:1, or about 4:1 to about 2:1, but is not necessarily limited to these ranges. The ratio may be selected based on the desired performance characteristics of the all-solid-state battery. By configuring a negative electrode active material having this composition, the cycle performance of the solid-state battery can be further improved.

[0211] The negative electrode active material layer 22 may comprise a combination of first particles composed of amorphous carbon and second particles composed of metal or metalloid materials. For example, the metal or metalloid material may include gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn). The metalloid may alternatively be a semiconductor. The content of the second particles is approximately 8% to approximately 60% by weight, approximately 10% to approximately 50% by weight, approximately 15% to approximately 40% by weight, or approximately 20% to approximately 30% by weight, based on the total weight of the mixture. By controlling the content of the second particles within these ranges, the cycle performance of the solid-state battery can be further enhanced.

[0212] For example, the adhesive included in the negative electrode active material layer 22 may be styrene-butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, vinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, polymethyl methacrylate, etc., but is not limited to these, and any adhesive used in the relevant technical field may be used. The adhesive may consist of a single type of adhesive or a combination of multiple different adhesives.

[0213] By including an adhesive, the negative electrode active material layer 22 can be stabilized on the negative electrode current collector 21. Additionally, the adhesive helps suppress cracking of the negative electrode active material layer 22 during charging and discharging processes, even when its volume changes or its relative position shifts. For example, if the negative electrode active material layer 22 did not include an adhesive, it could easily detach from the negative electrode current collector 21. If the negative electrode active material layer 22 detaches, it exposes a portion of the negative electrode current collector 21, which can then come into contact with the solid electrolyte layer, increasing the likelihood of a short circuit. The negative electrode active material layer 22 can be prepared by applying a slurry in which the constituent materials of the negative electrode active material layer 22 are dispersed onto the negative electrode current collector 21 and then drying it. Including an adhesive in the negative electrode active material layer 22 allows for stable dispersion of the negative electrode active material in the slurry. For example, when the slurry is applied to the negative electrode current collector 21 using a screen printing method, screen clogging (e.g., clogging caused by agglomerates of the negative electrode active material) can be prevented.

[0214] The negative electrode active material layer 22 may further include additives commonly used in all-solid-state batteries, such as fillers, coating agents, dispersants, and ion conduction aids.

[0215] For example, the thickness of the negative electrode active material layer 22 may be 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, or 5% or less of the thickness of the positive electrode active material layer 12. For example, the thickness of the negative electrode active material layer 22 may be from about 1 micrometer (μm) to about 20 μm, from about 2 μm to about 10 μm, or from about 3 μm to about 7 μm. If the thickness of the negative electrode active material layer 22 is too thin, lithium dendrites formed between the negative electrode active material layer 22 and the negative electrode current collector 21 may cause the negative electrode active material layer 22 to collapse, making it difficult to improve the cycle characteristics of the all-solid-state battery. If the thickness of the negative electrode active material layer 22 is excessively increased, the energy density of the solid-state battery decreases, and the internal resistance of the solid-state battery increases due to the negative electrode active material layer 22, making it difficult to improve the cycle characteristics of the solid-state battery.

[0216] For example, if the thickness of the negative electrode active material layer 22 is reduced, the charging capacity of the negative electrode active material layer 22 also decreases. For example, compared to the charging capacity of the positive electrode active material layer 12, the charging capacity of the negative electrode active material layer 22 may be 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, 5% or less, 2% or less, or 1% or less. For example, compared to the charging capacity of the positive electrode active material layer 12, the charging capacity of the negative electrode active material layer 22 may be about 0.1% to about 50%, about 0.1% to about 40%, about 0.1% to about 30%, about 0.1% to about 20%, about 0.1% to about 10%, about 0.1% to about 5%, or about 0.1% to about 2%. If the charging capacity of the negative electrode active material layer 22 is too small, the thickness of the negative electrode active material layer 22 becomes very thin. This allows lithium dendrites to form between the negative electrode active material layer 22 and the negative electrode current collector 21 during repeated charging and discharging processes, causing the negative electrode active material layer 22 to collapse and making it difficult to improve the cycle characteristics of the all-solid-state battery. If the charging capacity of the negative electrode active material layer 22 is excessively increased, the energy density of the all-solid-state battery decreases, and the internal resistance of the all-solid-state battery increases due to the negative electrode active material layer 22, making it difficult to improve the cycle characteristics of the all-solid-state battery.

[0217] The charging capacity of the positive electrode active material layer 12 is obtained by multiplying the charging capacity density (mAh / g) of the positive electrode active material by the mass of the positive electrode active material in the positive electrode active material layer 12. If multiple types of positive electrode active materials are used, the charging capacity density × mass is calculated for each positive electrode active material, and the sum represents the charging capacity of the positive electrode active material layer 12. The charging capacity of the negative electrode active material layer 22 is calculated in the same way. That is, the charging capacity of the negative electrode active material layer 22 is obtained by multiplying the charging capacity density (mAh / g) of the negative electrode active material by the mass of the negative electrode active material in the negative electrode active material layer 22. If multiple negative electrode active materials are used, the charging capacity density × mass is calculated for each negative electrode active material, and the sum represents the charging capacity of the negative electrode active material layer 22. Here, a solid-state half-cell battery using lithium metal as the counter electrode is used to evaluate the charging capacity density of the positive and negative electrode active materials. The charging capacity of the positive electrode active material layer 12 and the negative electrode active material layer 22 is directly measured by measuring the charging capacity using a solid-state half-cell battery. The charge capacity density is obtained by dividing the measured charge capacity by the mass of the corresponding active material. Alternatively, the charge capacity of the positive electrode active material layer 12 and the negative electrode active material layer 22 can be the initial charge capacity measured during the first charge cycle.

[0218] refer to Figure 12The solid-state battery 50a may further include, for example, a metal layer 23 disposed between the negative electrode current collector 21 and the negative electrode active material layer 22. The metal layer 23 may be a metal foil or a plated metal layer. The metal layer 23 may contain lithium or a lithium alloy. Therefore, the metal layer 23 can act as, for example, a lithium reservoir. For example, the lithium alloy may include, but is not limited to, Li-Al alloys, Li-Sn alloys, Li-In alloys, Li-Ag alloys, Li-Au alloys, Li-Zn alloys, Li-Ge alloys, or Li-Si alloys, and may include any lithium alloy commonly used in the art. The metal layer 23 may be composed of lithium, one type of lithium alloy, or multiple types of lithium alloys.

[0219] The thickness of the metal layer 23 is not particularly limited, but it can range from about 1 μm to about 200 μm, about 1 μm to about 100 μm, about 1 μm to about 70 μm, about 1 μm to about 50 μm, about 1 μm to about 30 μm, or about 1 μm to about 20 μm. If the thickness of the metal layer 23 is too thin, it may be difficult for the metal layer 23 to function as a lithium storage device. If the thickness of the metal layer 23 is too thick, the mass and volume of the solid-state battery may increase, and the cycle characteristics may deteriorate. For example, the metal layer 23 can be a metal foil having a thickness within these ranges.

[0220] In the all-solid-state battery 50a, the metal layer 23 can be disposed between the negative electrode current collector 21 and the negative electrode active material layer 22 before assembling the all-solid-state battery 50a, or it can be deposited between the negative electrode current collector 21 and the negative electrode active material layer 22 after assembling the all-solid-state battery 50a by charging. When the metal layer 23 is disposed between the negative electrode current collector 21 and the negative electrode active material layer 22 before assembling the solid-state battery 50a, the metal layer 23 is a lithium-containing metal layer and thus acts as a lithium storage device. For example, a lithium foil can be disposed between the negative electrode current collector 21 and the negative electrode active material layer 22 before assembling the solid-state battery 50a. As a result, the cycle characteristics of the solid-state battery 50a including the metal layer 23 can be further improved. If the metal layer 23 is deposited by charging after assembling the all-solid-state battery 50a, the energy density of the all-solid-state battery 50a increases because the metal layer 23 is not included during assembly. For example, during the charging of the all-solid-state battery 50a, the negative electrode active material layer 22 is charged beyond its storage capacity. That is, the negative electrode active material layer 22 is overcharged. During the initial stage of charging, lithium is absorbed into the negative electrode active material layer 22. The negative electrode active material included in the negative electrode active material layer 22 forms an alloy or compound with lithium ions moving from the positive electrode layer 10. When the charge exceeds the capacity of the negative electrode active material layer 22, lithium can be deposited on the back surface of the negative electrode active material layer 22, that is, between the negative electrode current collector 21 and the negative electrode active material layer 22, and the deposited lithium can form a metal layer corresponding to the metal layer 23. The metal layer 23 can be a metal layer mainly composed of lithium (i.e., metallic lithium). For example, this result is obtained when the negative electrode active material included in the negative electrode active material layer 22 is composed of a material that forms an alloy or compound with lithium. During discharge, the lithium in the negative electrode active material layer 22 and the metal layer 23, that is, the lithium in the metal layer, can be ionized and move towards the positive electrode layer 10. Therefore, in the solid-state battery 50a, lithium can be used as a negative electrode active material. Furthermore, since the negative electrode active material layer 22 covers the metal layer 23, it can act as a protective layer for the metal layer 23 (i.e., the metal layer), and simultaneously, it can suppress the precipitation and growth of lithium dendrites. Therefore, short circuits and capacity reduction in the solid-state battery 50a can be suppressed, thus improving the cycle characteristics of the solid-state battery 50a. Moreover, if the metal layer 23 is formed during charging after the solid-state battery 50a is assembled, the region between the negative electrode current collector 21 and the negative electrode active material layer 22 is, for example, a Li-free region that does not contain lithium Li in the initial state or after the full solid-state battery 50a has been discharged.

[0221] For example, the negative electrode current collector 21 may be made of a material that does not react with lithium (i.e., does not form an alloy or compound). The materials constituting the negative electrode current collector 21 may include, but are not limited to, copper (Cu), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), and nickel (Ni), and any material that can be used as an electrode current collector in the relevant art can be used. The negative electrode current collector 21 may be made of a single type of metal from the above-mentioned metals, or may be made of an alloy or coated material of two or more metals. The negative electrode current collector 21 may be in the form of, for example, a plate or foil.

[0222] For example, the all-solid-state battery 50, 50a may further include a thin film (not shown) containing an element capable of forming an alloy with lithium on the negative electrode current collector 21. The thin film may be disposed between the negative electrode current collector 21 and the negative electrode active material layer 22. For example, the thin film may include an element capable of forming an alloy with lithium. Such elements may include, for example, gold (Au), silver (Ag), zinc (Zn), tin (Sn), indium (In), silicon (Si), aluminum (Al), and bismuth (Bi), but are not limited to these, as any element capable of forming an alloy with lithium in the art may be used. The thin film may consist of a single type of metal or may be made of an alloy of multiple types of metals. For example, by disposing the thin film on the negative electrode current collector 21, the deposition morphology of the metal layer 23 precipitated between the thin film and the negative electrode active material layer 22 becomes flatter, thereby further improving the cycle characteristics of the solid-state battery 50a.

[0223] For example, the thickness of the thin film can be from about 1 nm to about 800 nm, from about 10 nm to about 700 nm, from about 50 nm to about 600 nm, or from about 100 nm to about 500 nm. If the thickness of the thin film is less than 1 nm, the thin film may have difficulty functioning. If the thickness of the thin film is too thick, the thin film itself absorbs lithium, which reduces the amount of lithium deposited from the negative electrode, reduces the energy density of the solid-state battery, and degrades the cycle characteristics of the solid-state batteries 50 and 50a. The thin film can be formed on the negative electrode current collector 21 by, for example, vacuum deposition, sputtering, plating, etc., but is not limited to these methods, and any method capable of forming a thin film in the relevant art is possible.

[0224] [Preparation Methods for All-Solid-State Batteries]

[0225] According to another embodiment of this disclosure, a method for fabricating an all-solid-state battery may include: providing a first laminate including a positive electrode and a first solid electrolyte layer on the positive electrode, and a second laminate including a negative electrode and a second solid electrolyte layer on the negative electrode; providing an interlayer including an adhesive and a tackifier on one or more surfaces of the first solid electrolyte layer of the first laminate and the second solid electrolyte layer of the second laminate; stacking the first laminate and the second laminate such that the first solid electrolyte layer of the first laminate and the second solid electrolyte layer of the second laminate face each other to fabricate a third laminate; and applying pressure to the third laminate to manufacture an all-solid-state battery. The interlayer may include the adhesive and the tackifier.

[0226] In a method for fabricating a solid-state battery, the first and second stacks can be fabricated separately, then further stacked and pressurized, thereby enabling the continuous fabrication of the solid-state battery, for example, in a roll-to-roll manner. Because solid-state batteries can be fabricated continuously, they are suitable for the large-scale manufacturing of all-solid-state batteries.

[0227] Figures 13A to 13G A cross-sectional view showing the method for preparing a solid-state battery 50 according to an embodiment.

[0228] First, a first laminate comprising a positive electrode 10 and a first solid electrolyte layer 30a on the positive electrode 10 is prepared.

[0229] refer to Figure 13A The positive electrode 10 is prepared. For example, the positive electrode 10 can be used to manufacture... Figures 7 to 11 The method described above for preparing the positive electrode 10 of the solid-state battery 50 may include, for example, a positive electrode current collector 11 and a positive electrode active material layer 12.

[0230] refer to Figure 13BThe first solid electrolyte layer 30a can be disposed on the positive electrode active material layer 12. For example, the first solid electrolyte layer 30a can be prepared by applying a slurry of the first solid electrolyte layer 30a, which can be prepared by mixing a first solid electrolyte, a binder, and a solvent, onto the positive electrode active material layer 12, and then drying it. Alternatively, the first solid electrolyte layer 30a can be prepared in the form of a solid electrolyte sheet by applying a slurry of the first solid electrolyte layer 30a, which can be prepared by mixing a solid electrolyte, a binder, and a solvent, onto a separate substrate, then drying it and subsequently separating it from the substrate. The solid electrolyte sheet can be disposed on the positive electrode active material layer 12. For example, the solid electrolyte sheet can be a self-supporting solid electrolyte layer. Any solvent can be used, as long as it can dissolve the binder and uniformly mix the solid electrolyte and the binder to produce the slurry of the first solid electrolyte layer 30a. For example, the solvent can be octyl acetate.

[0231] A first solid electrolyte layer 30a can be disposed on the positive electrode 10 to prepare a first laminate. The first laminate can be further pressurized. By applying pressure, the surface uniformity of the first solid electrolyte layer 30a can be improved, and the bonding strength between the positive electrode active material layer 12 and the first solid electrolyte layer 30a can be improved.

[0232] Next, a second laminate comprising a negative electrode 20 and a second solid electrolyte layer 30b on the negative electrode 20 is prepared.

[0233] refer to Figure 13C The negative electrode 20 is prepared. For example, the negative electrode 20 can be prepared using the method for preparing the negative electrode 20 of the solid-state battery 50 described above. For example, the negative electrode 20 may include a negative electrode current collector 21 and a negative electrode active material layer 22.

[0234] refer to Figure 13D The second solid electrolyte layer 30b can be disposed on the negative electrode active material layer 22. For example, the second solid electrolyte layer 30b can be prepared by applying a slurry of the second solid electrolyte layer 30b, which can be prepared by mixing a second solid electrolyte, a binder, and a solvent, onto the negative electrode active material layer 22, and then drying it. Alternatively, the second solid electrolyte layer 30b can be prepared in the form of a solid electrolyte sheet by applying a slurry of the second solid electrolyte layer 30b, which can be prepared by mixing a solid electrolyte, a binder, and a solvent, onto a separate substrate, then drying it and subsequently separating it from the substrate. The solid electrolyte sheet can be disposed on the negative electrode active material layer 22. For example, the solid electrolyte sheet can be a self-supporting solid electrolyte layer. Any solvent can be used, as long as it can dissolve the binder and uniformly mix the solid electrolyte and the binder to produce the slurry of the second solid electrolyte layer 30b. For example, the solvent can be octyl acetate.

[0235] The second solid electrolyte layer 30b can be disposed on the negative electrode 20 to prepare a second laminate. The second laminate can be further pressurized. Pressurization can improve the surface uniformity of the second solid electrolyte layer 30b and improve the bonding strength between the negative electrode active material layer 22 and the second solid electrolyte layer 30b.

[0236] Next, an interlayer comprising an adhesive and a tackifier is provided on one or more surfaces of the first solid electrolyte layer 30a of the first laminate and the second solid electrolyte layer 30b of the second laminate.

[0237] refer to Figure 13E The first interlayer 40a may be provided on the first solid electrolyte layer 30a. The first interlayer 40a may include an adhesive and a tackifier.

[0238] The first interlayer 40a can be provided by coating the first solid electrolyte layer 30a with a composition comprising an adhesive, a tackifier, and a solvent for forming the first interlayer 40a. For example, the coating can be applied by spraying or bar coating. Any solvent can be used, as long as it can dissolve the adhesive and the tackifier and can uniformly mix the adhesive and the tackifier to produce the composition for forming the first interlayer 40a. For example, the solvent can be dichloromethane.

[0239] Although not shown in the figure, a second interlayer 40b may be provided on another surface of the first solid electrolyte layer 30a.

[0240] Next, the first stack and the second stack can be stacked to prepare a third stack, such that the first solid electrolyte layer 30a of the first stack and the second solid electrolyte layer 30b of the second stack face each other.

[0241] refer to Figure 13F and 13G The first solid electrolyte layer 30a of the first laminate and the second solid electrolyte layer 30b of the second laminate can be arranged facing each other. The first laminate and the second laminate can be stacked to prepare the third laminate.

[0242] Since the first interlayer 40a disposed on the first solid electrolyte layer 30a may include an adhesive and a tackifier, the first laminate comprising the positive electrode 10 (which may include a positive electrode active material layer 12 disposed on the positive electrode current collector 11) and the second laminate comprising the negative electrode 20 (which may include a negative electrode active material layer 22 disposed on the negative electrode current collector 21) can be tightly stacked without pores. The second solid electrolyte layer 30b may be disposed on the negative electrode 20.

[0243] Next, pressure is applied to the third stack to manufacture a solid-state battery 50.

[0244] Applying pressure can enhance the bonding strength between the first and second laminates. The first and second laminates can be stacked and pressed simultaneously or sequentially (e.g., in a roll-to-roll process) to prepare a solid secondary battery 50.

[0245] According to another embodiment of this disclosure, a method for fabricating an all-solid-state battery may include: providing a first laminate including a positive electrode and a third solid electrolyte layer on the positive electrode, and a second laminate including a negative electrode and a fourth solid electrolyte layer on the negative electrode; stacking the first laminate and the second laminate such that the third solid electrolyte layer of the first laminate and the fourth solid electrolyte layer of the second laminate are face-to-face to form a third laminate; and applying pressure to the third laminate to fabricate an all-solid-state battery. One or more of the third solid electrolyte layer and the fourth solid electrolyte layer may include an adhesive and a tackifier. The method for fabricating a solid-state battery may be the same as the method for fabricating a solid-state battery including the interlayer, except that providing the interlayer may be omitted.

[0246] The present disclosure will be described in detail below with reference to embodiments and comparative examples, but the present disclosure is not limited to the following embodiments.

[0247] Preparation of lithium-ion conductors

[0248] Example 1: Positive electrode / solid electrolyte layer (SE+TA) / solid electrolyte layer (SE+TA) / negative electrode (second structure)

[0249] Positive electrode preparation

[0250] As a positive electrode active material, LiNi coated with Li2O-ZrO2 (LZO) is prepared. 0.8 Co 0.15 Al 0.05O2 (NCM). A solid electrolyte, Li6PS5Cl, a silicogermanium sulfide crystalline solid electrolyte (D50 = 0.5 μm, crystalline), was used. Polytetrafluoroethylene (PTFE) was chosen as the binder. Carbon nanofibers (CNF) were used as the conductive agent. These materials were mixed with xylene solvent at a weight ratio of 84:11.5:3:1.5 for the positive electrode active material: solid electrolyte: conductive agent: binder to form a slurry, which was then molded into a sheet. The sheet was vacuum dried at 40°C for 8 hours to prepare the positive electrode sheet. The prepared positive electrode sheet was placed on the carbon-coated surface of an aluminum foil positive electrode current collector and rolled to prepare a positive electrode with a positive electrode current collector / positive electrode active material layer structure. The total thickness of the positive electrode was approximately 120 μm. The thickness of the positive electrode active material layer was approximately 95 μm, and the thickness of the carbon-coated aluminum foil was approximately 25 μm.

[0251] Anode preparation

[0252] A 10 μm thick SUS foil was prepared as the negative electrode current collector. Carbon black (CB) with a primary particle size of about 30 nm and silver (Ag) particles with an average particle size of about 60 nm were used as the negative electrode active materials.

[0253] Four grams (g) of a mixture of carbon black (CB) and silver particles in a 3:1 weight ratio were placed in a container, followed by the addition of 4 g of an NMP solution containing 7% by weight of PVDF binder (Kureha #9300) to prepare a mixed solution. NMP was gradually added to the prepared mixed solution while stirring to produce a slurry. The prepared slurry was coated onto an SUS sheet using a bar coater, dried in air at 80°C for 10 minutes, and then vacuum-dried at 40°C for 10 hours to prepare a laminate. The prepared laminate was rolled to prepare a negative electrode with a first negative electrode active material layer / negative electrode current collector structure. The thickness of the first negative electrode active material layer was approximately 15 μm.

[0254] Preparation of solid electrolyte membranes

[0255] By adding 5 parts by weight of an acrylic binder (Zeon A751, molecular weight 100,000 to 500,000 Daltons) as a binder and 5 parts by weight of a solid petroleum resin (HIKOREZ T-3100, Kolon Industries) as a tackifier to 90 parts by weight of a Li6PS5Cl solid electrolyte (D) with a sulfide-germanium ore-type crystalline structure. 50=3.0 μm, crystallized) to prepare a mixture. Octyl acetate was gradually added to the prepared mixture while stirring to form a slurry. The prepared slurry was coated onto a nonwoven fabric placed on a PET substrate using a bar coater and dried in air at 80°C for 10 minutes to form a laminated structure. The prepared laminate was vacuum dried at 80°C for 2 hours. The dried laminate was then separated from the substrate to prepare a solid electrolyte membrane. The solid electrolyte membrane is a self-supporting solid electrolyte membrane. The thickness of the solid electrolyte self-supporting membrane is approximately 30 μm.

[0256] The solid petroleum resin (HIKOREZ T-3100, Kolon Industries) is a C5-C9 copolymer resin, wherein the C9 fraction content is 10% by weight or more of the total weight of the C5 and C9 fractions. The C5-C9 copolymer is obtained from a mixture of C5 and C9 fractions, which includes 1,3-pentadiene, isoprene, cyclopentadiene, vinyltoluene, styrene, and indene. The softening point of the solid petroleum resin (HIKOREZ T-3100, Kolon Industries) is 100°C as measured according to ASTM E 28, and its molecular weight is 2,000 Daltons as determined by gel permeation chromatography (GPC) using polystyrene standards.

[0257] Preparation of the first layer - positive electrode / solid electrolyte

[0258] The solid electrolyte self-supporting membrane is placed on the positive electrode active material layer of the positive electrode, and heated and rolled at 100°C with a linear pressure of 3 tons / cm to prepare a first laminate having a positive electrode / first solid electrolyte layer structure.

[0259] Preparation of the second-layer composite - negative electrode / solid electrolyte

[0260] The solid electrolyte self-supporting membrane is placed on the first negative electrode active material layer of the negative electrode, and heated and rolled at 100°C with a linear pressure of 2.5 tons / cm to prepare a second laminate with a negative electrode / second solid electrolyte layer structure.

[0261] Preparation of solid secondary batteries

[0262] The first and second laminates are stacked such that the first and second solid electrolyte layers face each other. Then, a heated rolling process is applied at 100°C with a linear pressure of 0.2 tons / cm and a speed of 0.5 meters / minute (mpm) to prepare a solid secondary battery.

[0263] The solid-state secondary battery has a structure of positive electrode / solid electrolyte layer / solid electrolyte layer / negative electrode.

[0264] Example 2: Positive electrode / solid electrolyte layer (SE+TA) / solid electrolyte layer (SE+TA) / negative electrode (second structure)

[0265] The solid electrolyte membrane and solid secondary battery were prepared in the same manner as in Example 1, except that when preparing the solid electrolyte membrane, 5 parts by weight of acrylic binder and 1.5 parts by weight of solid petroleum resin (HIKOREZ T-3100, KOLON Industries) were used for 90 parts by weight of solid electrolyte.

[0266] Example 3: Positive electrode / solid electrolyte layer (SE+TA) / solid electrolyte layer (SE+TA) / negative electrode (second structure)

[0267] The solid electrolyte membrane and solid secondary battery were prepared in the same manner as in Example 1, except that in the preparation of the solid electrolyte membrane, 5 parts by weight of acrylic binder and 0.75 parts by weight of solid petroleum resin (HIKOREZ T-3100, KOLON Industries) were used for 90 parts by weight of solid electrolyte.

[0268] Example 4: Positive electrode / solid electrolyte layer (SE+TA) / solid electrolyte layer (SE+TA) / negative electrode (second structure)

[0269] Solid electrolyte membranes and solid secondary batteries were prepared in the same manner as in Example 1, except that the solid petroleum resin (HIKOREZ T-3100, KOLON Industries) was changed to solid petroleum resin (HIKOREZ H-2300, KOLONIndustries). The solid petroleum resin (HIKOREZ H-2300, KOLON Industries) was a hydrogenated C5-C9 copolymer resin, wherein the C9 fraction content was less than 10% by weight of the total weight of the C5 and C9 fractions. The C5-C9 copolymer was obtained from a mixture of C5 and C9 fractions, including dicyclopentadiene, vinyltoluene, styrene, indene, etc. The softening point of the solid petroleum resin (HIKOREZ H-2300, Kolon Industries) was 100°C, as measured by ASTM E28, and the molecular weight was 570 Daltons, as measured by gel permeation chromatography (GPC) using a polystyrene standard sample.

[0270] Example 5: Positive electrode / solid electrolyte layer (SE+TA) / solid electrolyte layer (SE+TA) / negative electrode (second structure)

[0271] The solid electrolyte membrane and solid secondary battery were prepared in the same manner as in Example 1, except that the solid petroleum resin (HIKOREZ T-3100, Kolon Industries) was replaced with liquid petroleum resin (PMR OLG, Kolon Industries).

[0272] Liquid petroleum resin (PMR OLG, Kolon Industries) is a liquid C9 oligomer resin. This liquid C9 oligomer resin is derived from a composition containing high-purity polystyrene. The softening point of this liquid petroleum resin (PMR OLG, Kolon Industries), measured according to ASTM E 28, is 178°C, and its molecular weight, measured using polystyrene standards by gel permeation chromatography (GPC), is 450 Daltons.

[0273] Example 6: Positive electrode / solid electrolyte layer (SE+TA) / solid electrolyte layer (SE+TA) / negative electrode (second structure)

[0274] The solid electrolyte membrane and solid secondary battery were prepared in the same manner as in Example 1, except that in the preparation of the solid electrolyte membrane, 5 parts by weight of acrylic binder and 1.5 parts by weight of liquid petroleum resin (PMR OLG, Kolon Industries) were used for 90 parts by weight of solid electrolyte.

[0275] Example 7: Positive electrode / solid electrolyte layer (SE+TA) / solid electrolyte layer (SE+TA) / negative electrode (second structure)

[0276] The solid electrolyte membrane and solid secondary battery were prepared in the same manner as in Example 1, except that in the preparation of the solid electrolyte membrane, 5 parts by weight of acrylic binder and 0.75 parts by weight of liquid petroleum resin (PMR OLG, Kolon Industries) were used for 90 parts by weight of solid electrolyte.

[0277] Example 8: Positive electrode / solid electrolyte layer (SE+TA) / solid electrolyte layer (SE+TA) / negative electrode (second structure)

[0278] The solid electrolyte membrane and solid secondary battery were prepared in the same manner as in Example 1, except that the solid petroleum resin (HIKOREZ T-3100, KOLON Industries) was replaced with solid petroleum resin (HIKOREZ A-1100, KOLONIndustries). The solid petroleum resin (HIKOREZ A-1100, KOLON Industries) was a hydrogenated C5 resin. The C5 resin was derived from the C5 fraction and contained 1,3-pentadiene, isoprene, and cyclopentadiene. The softening point of the solid petroleum resin (HIKOREZ A-1100, Kolon Industries) was 100°C, as measured by ASTM E 28, and the molecular weight was 1950 Daltons, as measured by gel permeation chromatography (GPC) against a polystyrene standard.

[0279] Comparative Example 1: Positive Electrode / Solid Electrolyte Layer (SE) / Solid Electrolyte Layer (SE) / Negative Electrode

[0280] The positive and negative electrodes were prepared using the same method as in Example 1.

[0281] The solid electrolyte membrane was prepared using the same method as in Example 1, except that 5 parts by weight of an acrylic binder were used for 90 parts by weight of the solid electrolyte and no tackifier was used. The first laminate, the second laminate, and the solid secondary battery were prepared in the same manner as in Example 1, except that a solid electrolyte layer without a tackifier was used.

[0282] Example 9: Positive electrode / solid electrolyte layer (SE+TA) / interlayer (TA) / solid electrolyte layer (SE+TA) / negative electrode (first structure)

[0283] The positive electrode, negative electrode, solid electrolyte membrane, first laminate, and second laminate were prepared using the same method as in Example 1.

[0284] Preparation of all-solid-state secondary batteries

[0285] A mixture was prepared by adding 5 parts by weight of an acrylic binder and 1.5 parts by weight of a petroleum resin (HIKOREZ T-3100, Kolon Industries). The prepared mixture was dissolved in dichloromethane (CH2Cl2) solvent to prepare a sandwich-forming composition. The sandwich-forming composition was sprayed onto the first solid electrolyte layer of the first laminate and dried to introduce the sandwich. The loading level of the sandwich-forming composition was approximately 1.0 mg / cm³. 2On a dry weight basis, the first and second layers, in which the interlayer is introduced, are stacked such that the first and second solid electrolyte layers face each other, and then rolled at 100°C under a linear pressure of 0.2 tons / cm at a speed of 0.5 mpm to prepare a solid secondary battery. The resulting solid secondary battery has a positive electrode / solid electrolyte layer / interlayer / solid electrolyte layer / negative electrode structure.

[0286] Example 10: Positive electrode / solid electrolyte layer (SE+TA) / interlayer (TA) / solid electrolyte layer (SE+TA) / negative electrode (first structure)

[0287] The positive and negative electrodes were prepared using the same method as in Example 1. A solid electrolyte membrane was prepared using the same method as in Example 1, except that 5 parts by weight of an acrylic binder were used relative to 90 parts by weight of the solid electrolyte, and no tackifier was used.

[0288] The first and second laminates were prepared in the same manner as in Example 1, except that a solid electrolyte membrane without a thickener was used.

[0289] Preparation of solid secondary batteries

[0290] A mixture was prepared by adding 5 parts by weight of an acrylic binder and 1.5 parts by weight of a petroleum resin (HIKOREZ T-3100, KOLON Industries). The prepared mixture was dissolved in dichloromethane (CH2Cl2) solvent to prepare a sandwich-forming composition. The sandwich-forming composition was sprayed onto the first solid electrolyte layer of the first laminate and dried to introduce the sandwich. The loading level of the sandwich-forming composition was approximately 1.0 mg / cm³. 2 On a dry weight basis, the first and second layers, in which the interlayer is introduced, are stacked such that the first and second solid electrolyte layers face each other, and then rolled at 100°C under a linear pressure of 0.2 tons / cm at a speed of 0.5 mpm to prepare a solid secondary battery. The resulting solid secondary battery has a positive electrode / solid electrolyte layer / interlayer / solid electrolyte layer / negative electrode structure.

[0291] Evaluation Example 1: Measurement of Ionic Conductivity

[0292] The impedance of the solid secondary batteries prepared in Examples 1 to 10 and Comparative Example 1 was measured using a dual-probe method with an impedance analyzer (Solartron 1400A / 1455A impedance analyzer). The frequency range was set from 0.17 MHz to 1 Hz, and the amplitude voltage was 10 mV. Measurements were performed at 1 atm and 25°C in an atmospheric atmosphere. The resistance values ​​were obtained from the Nyquist plots of the impedance measurements, and the ionic conductivity at the interface between the stacked solid electrolyte layers was calculated. The results are shown in Table 1 below.

[0293] Table 1

[0294]

[0295] As shown in Table 1, compared with the battery of Comparative Example 1, the solid secondary batteries of Examples 1 to 10 exhibit improved ionic conductivity at the interface.

[0296] It was determined that the enhanced adhesion between the stacked solid electrolyte layers in the solid secondary batteries of Examples 1 to 10 led to a decrease in interfacial resistance, thereby causing an improvement in ionic conductivity at the interface between the stacked solid electrolyte layers.

[0297] Evaluation Example 2: Evaluation of Charging and Discharging Characteristics

[0298] The charge and discharge characteristics of the solid-state secondary batteries prepared in Examples 1 to 10 and Comparative Example 1 were evaluated by charge and discharge tests under the following conditions. The solid-state secondary batteries were tested by placing them in a constant temperature chamber at 45 °C.

[0299] The solid-state secondary battery was charged at a constant current at a 0.1C rate until the voltage reached 4.3 volts (V) (relative to Li). Then, the charging mode was switched to constant voltage mode, maintaining the 4.3 V voltage while reducing the current to 0.05C until cutoff. During discharge, the battery was discharged at a constant current at a 0.1C rate until the voltage dropped to 2.5 V (relative to Li) (formation cycle).

[0300] After formation cycling, the solid secondary battery was charged at a constant current at a rate of 0.2C until the voltage reached 4.3 V (relative to Li). Then, the battery was discharged at a constant current at a rate of 0.1C until the voltage dropped to 2.5 V (relative to Li) (first cycle).

[0301] After the first cycle, the solid-state secondary battery was charged at a constant current at a rate of 0.2C until the voltage reached 4.3 V (relative to Li). Then, the battery was discharged at a constant current at a rate of 0.33C until the voltage dropped to 2.5 V (relative to Li) (second cycle).

[0302] A 10-minute rest period was applied after each charge / discharge cycle. The results of the charge and discharge tests are shown in Table 2.

[0303] Calculate the initial efficiency using Equation 1:

[0304] Equation 1

[0305] Initial efficiency [%] = [Discharge capacity in the first cycle / Charge capacity in the first cycle] × 100

[0306] Evaluation Example 3: Evaluation of DC Internal Resistance (DC-IR)

[0307] The DC internal resistance (DC-IR) of the solid secondary batteries prepared in Examples 1 to 10 and Comparative Example 1 was measured using the following method.

[0308] In the first cycle, the battery is charged at a current of 0.2C until it reaches a voltage corresponding to a state of charge (SOC) of 20 volts (v%).

[0309] Then, a constant current discharge at 3.0C is performed for 10 seconds, followed by a constant current discharge at 0.2C for 10 seconds, and then another constant current discharge at 3.0C for 10 seconds.

[0310] DC-IR (R=ΔV / ΔI) is calculated based on the ratio of the average voltage change (ΔV) to the average current change (ΔI) observed at different C-rates during each constant current discharge.

[0311] The average of these calculated values ​​is used as the DC-IR record of the measurement.

[0312] Table 2

[0313]

[0314] As shown in Table 2, compared with Comparative Example 1, the solid-state secondary batteries from Examples 1, 2, 6, and 10 exhibited improved high-rate performance and cycle life characteristics. Furthermore, the increase in internal resistance was suppressed.

[0315] It was determined that in the solid secondary batteries from Examples 1 to 10, the enhanced adhesion of the solid electrolyte membrane resulted in the suppression of void formation and cracking during charge and discharge cycles, thereby preventing degradation.

[0316] Evaluation Example 4: Battery Stability Evaluation

[0317] The charge and discharge characteristics of the solid-state secondary batteries from Examples 1 to 10 were evaluated by the following charge and discharge tests. The solid-state secondary batteries were tested by placing them in a constant temperature chamber at 45°C.

[0318] First cycle: Charge the battery at a constant current (CC) of 0.1C for 12.5 hours until the voltage reaches 4.3V. Then discharge the battery at a constant current (CC) of 0.2C for 12.5 hours until the voltage reaches 2.5V.

[0319] Subsequent cycles (second cycle and beyond): apply the same charging and discharging conditions as the first cycle up to 100 cycles.

[0320] refer to Figure 14 The solid-state battery prepared in Example 3 was confirmed to operate stably for up to 100 cycles.

[0321] Although this disclosure has been described according to embodiments, it is not limited thereto. Various modifications may be made within the scope of the claims, the detailed description of the invention, and the drawings, and these modifications should also be considered within the scope of the invention.

[0322] According to one aspect of this disclosure, the solid electrolyte membrane may include an adhesive and a tackifier to suppress void formation and electrical disconnection during charging and discharging, while providing enhanced adhesion and improved bonding strength.

[0323] According to another aspect of this disclosure, a solid-state battery may include a novel solid electrolyte membrane.

[0324] According to another aspect of this disclosure, a method for preparing a novel all-solid-state battery is provided.

[0325] It should be understood that the embodiments described herein should be considered in the descriptive sense only and are not intended for limiting purposes. The description of features or aspects within 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. Solid-state batteries, including: Positive electrode; negative electrode; and a solid electrolyte layer between the positive electrode and the negative electrode. The solid electrolyte layer includes one or more sub-solid electrolyte layers. The solid electrolyte layer may or may not include an interlayer between the plurality of sub-solid electrolyte layers. At least one of the sub-solid electrolyte layer and the interlayer includes a thickener. The tackifier comprises hydrocarbon oligomers derived from aliphatic chain monomers having 5 to 20 carbon atoms, aromatic cyclic monomers having 6 to 20 carbon atoms, aliphatic cyclic monomers having 5 to 20 carbon atoms, or combinations thereof.

2. The solid-state battery as described in claim 1, The sub-solid electrolyte layer includes a first solid electrolyte layer, a second solid electrolyte layer, a third solid electrolyte layer, a fourth solid electrolyte layer, and a fifth solid electrolyte layer. The solid electrolyte layer comprises: A first structure comprising a first solid electrolyte layer, a second solid electrolyte layer, and a first interlayer disposed between the first solid electrolyte layer and the second solid electrolyte layer; A second structure comprising a third solid electrolyte layer and a fourth solid electrolyte layer; or The third structure includes the fifth solid electrolyte layer.

3. The solid-state battery as described in claim 1, wherein... The thickener comprises a mixture of various hydrocarbon oligomers with different structures.

4. The solid-state battery as claimed in claim 1, wherein... The number of repeating units in the hydrocarbon oligomer is 100 or less.

5. The solid-state battery as claimed in claim 1, wherein... The tackifier further comprises an aliphatic chain monomer having 5 to 20 carbon atoms, an aromatic ring monomer having 6 to 20 carbon atoms, an aliphatic ring monomer having 5 to 20 carbon atoms, or a combination thereof.

6. The solid-state battery of claim 1, wherein... The thickener includes i) Unsaturated aliphatic hydrocarbon chain monomers having 5 to 20 carbon atoms, Oligomers of unsaturated aliphatic hydrocarbon chain monomers having 5 to 20 carbon atoms. or combinations thereof; i-1) Hydrogenates of unsaturated aliphatic hydrocarbon chain monomers having 5 to 20 carbon atoms. Hydrogenates of oligomers of unsaturated aliphatic hydrocarbon chain monomers having 5 to 20 carbon atoms. or combinations thereof; ii) Unsaturated aromatic hydrocarbon cyclic monomers having 6 to 20 carbon atoms, Oligomers of unsaturated aromatic hydrocarbon cyclic monomers having 6 to 20 carbon atoms. or combinations thereof; ii-1) Hydrates of unsaturated aromatic hydrocarbon ring monomers having 6 to 20 carbon atoms, Hydrates of oligomers of unsaturated aromatic hydrocarbon ring monomers having 6 to 20 carbon atoms. or combinations thereof; iii) Unsaturated aliphatic hydrocarbon cyclic monomers having 5 to 20 carbon atoms, Oligomers of unsaturated aliphatic hydrocarbon cyclic monomers having 5 to 20 carbon atoms. or a combination thereof; or iii-1) Hydrates of unsaturated aliphatic hydrocarbon cyclic monomers having 5 to 20 carbon atoms. Hydrates of oligomers of unsaturated aliphatic hydrocarbon cyclic monomers having 5 to 20 carbon atoms. Or a combination thereof.

7. The solid-state battery as claimed in claim 1, wherein The thickener includes i) trans-1,3-pentadiene, oligomers of trans-1,3-pentadiene, oligomers of cis-1,3-pentadiene, oligomers of cis-1,3-pentadiene, 2-methyl-2-butene, oligomers of 2-methyl-2-butene, or combinations thereof. i-1) Hydrogenates of trans-1,3-pentadiene, hydrides of trans-1,3-pentadiene oligomers, hydrides of cis-1,3-pentadiene, hydrides of cis-1,3-pentadiene oligomers, hydrides of 2-methyl-2-butene, hydrides of 2-methyl-2-butene oligomers, or combinations thereof; ii) Styrene, oligomers of styrene, α-methylstyrene, oligomers of α-methylstyrene, vinyltoluene, oligomers of vinyltoluene, indene, oligomers of indene, or combinations thereof; ii-1) Hydrogenates of styrene, hydrides of oligomers of styrene, hydrides of α-methylstyrene, hydrides of oligomers of α-methylstyrene, hydrides of vinyltoluene, hydrides of oligomers of vinyltoluene, hydrides of indene, hydrides of oligomers of indene, or combinations thereof. iii) Cyclopentene, oligomers of cyclopentene, cyclopentadiene, oligomers of cyclopentadiene, dicyclopentadiene, oligomers of dicyclopentadiene, or combinations thereof; or iii-1) Hydrogenates of cyclopentene, hydrides of oligomers of cyclopentene, hydrides of cyclopentadiene, hydrides of oligomers of cyclopentadiene, hydrides of dicyclopentadiene, hydrides of oligomers of dicyclopentadiene, or combinations thereof.

8. The solid-state battery as claimed in claim 1, wherein The tackifier is free of oxygen, nitrogen, fluorine, chlorine, sulfur, phosphorus, or combinations thereof.

9. The solid-state battery of claim 1, wherein... The tackifier includes amorphous hydrocarbon oligomers. The tackifier comprises the hydrocarbon oligomer having a molecular weight of less than 10,000 Daltons. The tackifier comprises the hydrocarbon oligomer having a softening point of less than 160°C as measured according to ASTM E 28, and The tackifier includes the hydrocarbon oligomer having a glass transition temperature of less than 160°C.

10. The solid-state battery as described in claim 1, The interlayer further includes an adhesive. The amount of the tackifier in the interlayer is from 1 part by weight to 100 parts by weight, based on 100 parts by weight of the adhesive.

11. The solid-state battery as described in claim 10, The loading level of the adhesive and the tackifier in the first interlayer is from 0.1 mg / cm² to 5 mg / cm².

12. The solid-state battery as described in claim 1, The thickness of the interlayer is from 0.01 micrometers to 10 micrometers, and The thickness of the interlayer is 50% or less of the thickness of the sub-solid electrolyte layer.

13. The solid-state battery as described in claim 2, The interlayer includes an interlayer solid electrolyte, and The sandwich solid electrolyte includes sulfide-based solid electrolytes, oxide-based solid electrolytes, halide-based solid electrolytes, oxyhalide-based solid electrolytes, or combinations thereof.

14. The solid-state battery as described in claim 2, At least one of the plurality of said sub-solid electrolyte layers does not contain the thickener.

15. The solid-state battery as described in claim 2, The first solid electrolyte layer and the second solid electrolyte layer each independently include: The first surface adjacent to the first interlayer; And a second surface opposite to the first surface and spaced apart from the first interlayer; as well as The region between the first surface and the second surface that does not contain the tackifier.

16. The solid-state battery as described in claim 2, One or both of the first solid electrolyte layer and the second solid electrolyte layer include an adhesive and a tackifier, and If present, the amount of the tackifier in the first solid electrolyte layer, the second solid electrolyte layer, the third solid electrolyte layer, the fourth solid electrolyte layer, and the fifth solid electrolyte layer is independently from 1 part by weight to 100 parts by weight, based on 100 parts by weight of the adhesive.

17. The solid-state battery as described in claim 2, The thicknesses of the first solid electrolyte layer, the second solid electrolyte layer, the third solid electrolyte layer, the fourth solid electrolyte layer, and the fifth solid electrolyte layer are independently between 5 micrometers and 200 micrometers.

18. The solid-state battery as described in claim 2, The first solid electrolyte layer, the second solid electrolyte layer, the third solid electrolyte layer, the fourth solid electrolyte layer, and the fifth solid electrolyte layer each independently include a solid electrolyte. The solid electrolytes mentioned include sulfide-based solid electrolytes, oxide-based solid electrolytes, halide-based solid electrolytes, oxyhalide-based solid electrolytes, or combinations thereof, and The sub-solid electrolyte layer is a self-supporting membrane.

19. The solid-state battery as described in claim 2, The first structure, the second structure, and the third structure each include a top surface and a bottom surface opposite to the top surface. The first structure, the second structure, and the third structure include a second interlayer disposed on the top surface or a third interlayer disposed on the bottom surface.

20. A method for preparing a solid-state battery, comprising: A first laminate and a second laminate are provided, the first laminate including a positive electrode and a first solid electrolyte layer on the positive electrode, and the second laminate including a negative electrode and a second solid electrolyte layer on the negative electrode; An interlayer is provided on one or more surfaces of the first solid electrolyte layer of the first laminate and the second solid electrolyte layer of the second laminate; The first stack and the second stack are stacked such that the first solid electrolyte layer of the first stack and the second solid electrolyte layer of the second stack face each other to provide a third stack. as well as Pressure is applied to the third stack to prepare the solid-state battery. The interlayer includes a tackifier.

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