All-solid-state battery, positive electrode, and method of manufacturing solid electrolyte

Abstract

An all-solid-state battery, a positive electrode, and a method of manufacturing a solid electrolyte are disclosed. The positive electrode includes clusters including active material particles and solid electrolyte particles. The solid electrolyte particles are in contact with the active material particles. Each of the solid electrolyte particles includes a linear carbon-based conductive material dispersed in the solid electrolyte particles. The active material particles of the cluster are electrically connected to a first solid electrolyte particle among the solid electrolyte particles. Second solid electrolyte particles among the solid electrolyte particles and the first solid electrolyte particles are in contact with each other to form an electrical path by the linear carbon-based conductive material of the first solid electrolyte particles and the linear carbon-based conductive material of the second solid electrolyte particles.

Description

[0001] This application claims priority to Korean Patent Application No. 10-2024-0155280, filed on November 5, 2024, with the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference. Technical Field

[0002] Embodiments of this disclosure relate to all-solid-state batteries. Background Technology

[0003] The development of high-energy-density and safe batteries is increasingly driven by industrial demand. For example, lithium-ion batteries are being commercialized not only in formation-related and communication devices, but also in the automotive industry. In the automotive industry, safety is emphasized because it is directly related to the safety of human life.

[0004] All-solid-state batteries typically include a solid electrolyte instead of a liquid electrolyte. Because all-solid-state batteries do not use flammable organic dispersion media, the likelihood of fire or explosion is significantly reduced, even in the event of a short circuit. Therefore, all-solid-state batteries can exhibit high stability. Summary of the Invention

[0005] An exemplary embodiment of this disclosure provides a solid electrolyte in which conductive material is dispersed within particles to improve the electronic and ionic conductivity of the positive electrode.

[0006] An exemplary embodiment of this disclosure provides a positive electrode in which particles are uniformly mixed to improve electrode performance.

[0007] According to an example embodiment of this disclosure, the positive electrode for an all-solid-state battery may include a cluster comprising active material particles and a plurality of solid electrolyte particles. The plurality of solid electrolyte particles may be in contact with the active material particles. Each of the plurality of solid electrolyte particles may include a linear carbon-based conductive material dispersed within the solid electrolyte particles. The active material particles of the cluster may be electrically connected to a first solid electrolyte particle among the plurality of solid electrolyte particles. A second solid electrolyte particle among the plurality of solid electrolyte particles may be in contact with the first solid electrolyte particle to form an electrical path through the linear carbon-based conductive material of the first solid electrolyte particle and the linear carbon-based conductive material of the second solid electrolyte particle.

[0008] According to an example embodiment of this disclosure, an all-solid-state battery may include: a positive electrode, including a positive electrode current collector and a positive electrode active material layer on the positive electrode current collector; a solid electrolyte layer; and a negative electrode. The positive electrode active material layer may include positive electrode active material particles and first solid electrolyte particles. The first solid electrolyte particles may include a linear carbon-based conductive material dispersed within the first solid electrolyte particles. The linear carbon-based conductive material may be configured to penetrate the first solid electrolyte particles to form an electrical path between a first location and a second location on the surface of the first solid electrolyte particles.

[0009] According to an example embodiment of this disclosure, a method for manufacturing a solid electrolyte may include the steps of: mixing an electrolyte precursor and a linear carbon-based conductive material to obtain a mixture; and heat-treating the mixture to prepare solid electrolyte particles. The linear carbon-based conductive material may be configured to penetrate the solid electrolyte particles to form an electrical path between a first location and a second location on the surface of the solid electrolyte particles. Attached Figure Description

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

[0011] Figure 2 It shows along Figure 1 A sectional view taken by line A-A'.

[0012] Figure 3 It shows Figure 2 An enlarged cross-sectional view of the portion “M” depicted in the figure shows the positive electrode active material layer according to an exemplary embodiment of the present disclosure.

[0013] Figure 4 A diagram illustrating a cluster according to an example embodiment of the present disclosure is shown.

[0014] Figure 5 A diagram is shown illustrating solid electrolyte particles according to an example embodiment of the present disclosure.

[0015] Figure 6 An enlarged view of the positive electrode active material layer according to an example embodiment of the present disclosure is shown.

[0016] Figure 7 A cross-sectional view of an all-solid-state battery according to an example embodiment of the present disclosure is shown.

[0017] Figure 8 A cross-sectional view of an all-solid-state battery according to an example embodiment of the present disclosure is shown.

[0018] Figure 9 A cross-sectional view of an all-solid-state battery according to an example embodiment of the present disclosure is shown.

[0019] Figure 10 This is a flowchart illustrating a method for manufacturing a solid electrolyte according to an exemplary embodiment of the present disclosure. Detailed Implementation

[0020] Because the exemplary inventive concepts described below allow for various modifications and numerous exemplary embodiments, specific embodiments are illustrated in the accompanying drawings and described in detail in the specific description. However, it is not intended to limit the disclosure to the specific forms disclosed, but rather, the disclosure will cover any and all modifications, equivalents, and substitutions falling within the spirit and scope of the disclosure.

[0021] The terminology used in this specification is for describing specific exemplary embodiments only and is not intended to limit this disclosure. Unless the context clearly distinguishes them, expressions used in the singular include plural expressions. Hereinafter, it will be understood that terms such as “comprising” or “having” are intended to indicate the presence of the features, figures, operations, components, parts, elements, materials, or combinations thereof disclosed in the specification, and are not intended to exclude the possibility that one or more other features, figures, operations, components, parts, elements, materials, or combinations thereof may be present or added. As used herein, “ / ” can be interpreted as “and” or “or”.

[0022] Unless otherwise specified in this specification, singular expressions may include plural expressions. Additionally, unless otherwise specified, the phrase "A or B" may mean "A but not B," "B but not A," and "A and B." The terms "including / comprise" and / or variations thereof as used in this specification do not exclude the presence or addition of one or more other components.

[0023] In this specification, the term "combination thereof" may refer to mixtures, stacks, complexes, copolymers, alloys, blends, or reaction products.

[0024] In the accompanying drawings, the thickness of layers and regions may be enlarged or reduced for clarity. Throughout the specification, the same reference numerals denote the same elements. Throughout the specification, it will be understood that when an element such as a layer, region, or plate is referred to as being "on" another element, that element may be directly on said other element, or an intervening element may be present between them. It will be understood that although the terms first, second, etc., may be used herein to describe various components, these components should not be limited by these terms. In this specification and the accompanying drawings, components having substantially the same functional characteristics are indicated by the same reference numerals, and redundant descriptions are omitted for brevity.

[0025] In this disclosure, the term "size" of a particle refers to, for example, the "particle diameter". The term "particle diameter" refers to the average diameter when the particle is spherical, and to the average major axis length when the particle is non-spherical. Particle diameter can be measured using a particle size analyzer (PSA). "Particle diameter" is, for example, the average particle diameter. The average particle diameter refers to, for example, the median particle diameter (D50). The median particle diameter (D50) is the particle diameter corresponding to 50% of the cumulative volume when calculated from the particle size distribution measurement by laser diffraction, starting from the particle with the smallest diameter.

[0026] In this specification, the term "metal" includes metals or metalloids in elemental or ionic states, such as silicon and germanium.

[0027] In this specification, the term "alloy" refers to a mixture of two or more metals.

[0028] In this specification, the term "positive electrode active material" refers to a positive electrode material that can undergo lithiation and delithiation.

[0029] In this specification, the term "negative electrode active material" refers to a negative electrode material that can undergo lithiation and delithiation.

[0030] In this specification, the terms "lithiation" and "performing lithiation" refer to the process of adding lithium to the positive electrode active material or the negative electrode active material.

[0031] In this specification, the terms "delithiation" and "performing delithiation" refer to the process of removing lithium from the active material of the positive electrode or the active material of the negative electrode.

[0032] In this specification, the terms “charging” and “performing a charge” refer to the process of providing electrochemical energy to the battery.

[0033] In this specification, the terms "positive electrode" and "cathode" refer to the electrode that undergoes electrochemical reduction and lithiation during the discharge process.

[0034] In this specification, the terms "negative electrode" and "anode" refer to the electrode that undergoes electrochemical oxidation and delithiation during the discharge process.

[0035] The following description focuses on all-solid-state batteries and methods of manufacturing the same, based on some exemplary embodiments of the present disclosure.

[0036] When the terms “about” or “substantially” are used in conjunction with numerical values ​​in this specification, it is intended that the relevant numerical value includes a tolerance of ±10% around the stated value. The expression “at most” includes the quantity from zero to the stated upper limit and all values ​​in between. When a range is specified, the range includes all values ​​in between, such as increments of 0.1%.

[0037] All-solid-state batteries Figure 1A plan view illustrating an all-solid-state battery according to an example embodiment of the present disclosure is shown. Figure 2 It shows along Figure 1 A sectional view taken by line A-A'. Figure 3 It shows Figure 2 An enlarged cross-sectional view of the portion “M” depicted in the figure shows the positive electrode active material layer according to an exemplary embodiment of the present disclosure. Figure 4 A diagram illustrating a cluster according to an example embodiment of the present disclosure is shown. Figure 5 A diagram is shown illustrating solid electrolyte particles according to an example embodiment of the present disclosure. Figure 6 An enlarged view of the positive electrode active material layer according to an example embodiment of the present disclosure is shown.

[0038] Reference Figure 1 and Figure 2 The all-solid-state battery 10 according to the examples of this disclosure may include a positive electrode 100, a negative electrode 200 opposite to the positive electrode 100, and a solid electrolyte layer 300 between the positive electrode 100 and the negative electrode 200. However, this disclosure is not limited thereto, and the all-solid-state battery 10 may also include additional functional layers or more layers, such as an adhesion-enhancing layer, between the positive electrode 100 and the solid electrolyte layer 300 or between the negative electrode 200 and the solid electrolyte layer 300.

[0039] positive electrode According to an example embodiment, the positive electrode 100 may include a positive electrode current collector 110 and a positive electrode active material layer 120 on the positive electrode current collector 110. The positive electrode active material layer 120 may include a positive electrode active material. The positive electrode active material layer 120 may also include one or more of a solid electrolyte, a binder, and a conductive material.

[0040] The positive electrode current collector 110 can provide a reference surface on which the positive electrode active material layer 120 is disposed. The positive electrode current collector 110 may include at least one of, for example, indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li), and alloys thereof. The positive electrode current collector 110 may have a plate or foil shape. In exemplary embodiments of this disclosure, the positive electrode current collector 110 may not be provided. The positive electrode current collector 110 may have a thickness in the range of, for example, about 1 μm to about 100 μm, about 1 μm to about 50 μm, about 5 μm to about 25 μm, or about 10 μm to about 20 μm.

[0041] The positive electrode current collector 110 may include, for example, a substrate film and a metal layer disposed on one or opposite sides of the substrate film. The substrate film may include, for example, a polymer. The polymer may be, for example, a thermoplastic polymer. The polymer may include, for example, at least one of polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polybutylene terephthalate (PBT), polyimide (PI), and combinations thereof.

[0042] The substrate film may be or include, for example, an insulator. Because the substrate film comprises a dielectric thermoplastic polymer, it can soften or liquefy to block battery operation in the event of a short circuit, thereby reducing or suppressing a rapid increase in current.

[0043] The metal layer may include at least one of, for example, indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li), and their alloys. The metal layer can act as an electrochemical fuse and thus can disconnect in the event of overcurrent to provide protection against short circuits. The thickness of the metal layer can be adjusted to control the limiting current and maximum current. The metal layer can be plated or deposited on a substrate film. Because a reduction in the thickness of the metal layer leads to a reduction in the limiting current and / or maximum current, the stability of the lithium battery during short circuits can be improved.

[0044] Additional lead terminals for external connections may be provided on the metal layer. These lead terminals can be welded to the metal layer, or to a stack of the metal layer and the substrate film, using methods such as ultrasonic welding, laser welding, or spot welding. One or both of the substrate film and the metal layer can be melted, allowing the metal layer to be electrically connected to the lead terminals.

[0045] A metal sheet may be disposed between the metal layer and the lead patch to achieve a strong solder joint between the metal layer and the lead patch. The metal sheet may be a thin sheet formed of the same material as the metal layer. The metal sheet may be or include, for example, metal foil or metal mesh. The metal sheet may be or include at least one of, for example, aluminum foil, copper foil, and stainless steel (SUS) foil. When the metal sheet is placed on the metal layer and then soldered to the lead patch, the lead patch may be soldered to a stack of the metal sheet and the metal layer, or to a stack of the metal sheet, the metal layer, and the substrate film. One or more of the substrate film, the metal layer, and the metal sheet may melt during soldering, so that the metal layer or the stack of the metal layer and the metal sheet may be electrically connected to the lead patch. One or both of the metal sheet and the lead patch may be added to a portion of the metal layer.

[0046] The substrate film can have a thickness in the range of, for example, about 1 μm to about 50 μm, about 1.5 μm to about 50 μm, about 1.5 μm to about 40 μm, or about 1 μm to about 30 μm. Because the substrate film has a thickness within these ranges, the weight of the electrode assembly can be effectively reduced. The melting point of the substrate film can be in the range of, for example, about 100°C to about 300°C, about 100°C to about 250°C, or about 100°C to about 200°C. Because the substrate film has a melting point within these ranges, it can melt and easily connect to the lead terminals during the soldering process. To improve the adhesion between the substrate film and the metal layer, the substrate film can be surface-treated, such as by corona treatment.

[0047] The metal layer can have a thickness in the range of, for example, about 0.01 μm to about 3 μm, about 0.1 μm to about 3 μm, about 0.1 μm to about 2 μm, or about 0.1 μm to about 1 μm. Because the metal layer has a thickness within the above range, the stability of the electrode assembly can be ensured while maintaining conductivity. The metal sheet can have a thickness in the range of, for example, about 2 μm to about 10 μm, about 2 μm to about 7 μm, or about 4 μm to about 6 μm. Because the metal sheet has a thickness within the above range, the connection between the metal layer and the lead tab can be easily achieved. Because the positive electrode current collector 110 has a structure in which the substrate film and the metal layer are stacked, the weight of the positive electrode 100 can be reduced, resulting in improved energy density of the all-solid-state battery 10.

[0048] Positive electrode active material In exemplary embodiments of this disclosure, the positive electrode active material in the positive electrode active material layer 120 may be present in an amount ranging from about 10 wt% to about 99 wt%, about 30 wt% to about 80 wt%, about 40 wt% to about 70 wt%, or about 40 wt% to about 50 wt% of the total weight of the positive electrode active material layer 120. When the amount of positive electrode active material is very small or very small, the all-solid-state battery 10 may have a reduced energy density. When the amount of positive electrode active material is significantly large or very large, the volume of the positive electrode 100 may change, thereby promoting the degradation of the all-solid-state battery 10.

[0049] The positive electrode active material in the positive electrode active material layer 120 can reversibly insert and deintercalate lithium ions. The positive electrode active material may include multiple particles. The positive electrode active material according to the examples of this disclosure may include at least one of oxide-based positive electrode active materials, sulfide-based positive electrode active materials, and combinations thereof.

[0050] Oxide-based positive electrode active materials may include at least one of, for example, lithium transition metal oxides, metal oxides, and combinations thereof. Lithium transition metal oxides may include at least one of, for example, lithium cobalt oxide, lithium nickel oxide, lithium nickel cobalt oxide, lithium nickel cobalt aluminum oxide, lithium nickel cobalt manganese oxide, lithium manganese oxide, lithium iron phosphate, and combinations thereof. Metal oxides may include at least one of, for example, iron oxide, vanadium oxide, and combinations thereof.

[0051] The sulfide-based positive electrode active material layer may include at least one of, for example, nickel sulfide, copper sulfide, Li₂S, Li₂S-containing complexes, and combinations thereof. The sulfide-based positive electrode active materials according to exemplary embodiments of this disclosure are discussed in more detail below.

[0052] Oxide-based positive electrode active materials may include, for example, at least one composite oxide, said composite oxide comprising lithium and a metal, said metal being or including at least one of cobalt, manganese, nickel, and combinations thereof. Lithium-containing oxide-based positive electrode active materials may include compounds represented by one of the following chemical formulas: Li a A 1-b B' b D2 (where 0.90 ≤ a ≤ 1 and 0 ≤ b ≤ 0.5); Li a E 1-b B' b O 2-c D c (Where, 0.90≤a≤1, 0≤b≤0.5 and 0≤c≤0.05); LiE 2-b B' b O 4- c D c (Where, 0 ≤ b ≤ 0.5 and 0 ≤ c ≤ 0.05); Li a Ni 1-b-c Co b B' c D α (Where, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05 and 0<α≤2); Li a Ni 1-b-c Co b B' c O 2-α F' α (Where, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05 and 0<α<2); Li a Ni 1-b-c Mn b B' c D α (Where, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05 and 0<α≤2); Lia Ni 1-b-c Mn b B' c O 2-α F' α (Where, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05 and 0<α<2); Li a Ni b E c G d O2 (where 0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5 and 0.001≤d≤0.1); Li a Ni b Co c Mn d G e O2 (where 0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5 and 0.001≤e≤0.1); Li a NiG b O2 (where 0.9 ≤ a ≤ 1 and 0.001 ≤ b ≤ 0.1); Li a CoG b O2 (where 0.90≤a≤1 and 0.001≤b≤0.1); Li a MnG b O2 (where 0.90≤a≤1 and 0.001≤b≤0.1); Li a Mn2G b O4 (where 0.90≤a≤1 and 0.001≤b≤0.1); 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.

[0053] In the above compounds, A may be or include at least one of Ni, Co, Mn and combinations thereof; B' may be or include at least one of Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements and combinations thereof; D may be or include at least one of O, F, S, P and combinations thereof; E may be or include at least one of Co, Mn and combinations thereof; F' may be or include at least one of F, S, P and combinations thereof; G may be or include at least one of Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V and combinations thereof; I' may be or include at least one of Cr, V, Fe, Sc, Y and combinations thereof; and J may be or include at least one of V, Cr, Mn, Co, Ni, Cu and combinations thereof.

[0054] The oxide-based positive electrode active material may include, for example, a lithium salt of a transition metal oxide having a layered rock salt-type structure among the lithium transition metal oxides discussed above. The term "layered rock salt-type structure" may refer to a structure in which oxygen atom layers and metal atom layers are alternately and regularly arranged in the <111> direction of the cubic rock salt-type structure, where each atom layer forms a two-dimensional plane. The term "cubic rock salt-type structure" may refer to the sodium chloride (NaCl)-type structure as a crystal structure, and for example, has a structure in which face-centered cubic lattices (FCCs) each formed by cations and anions are shifted by 1 / 2 of the edges of the unit lattice. The lithium transition metal oxide having a layered rock salt-type structure may be a ternary lithium transition metal oxide, such as LiNi x Co y Al z O2 (NCA) or LiNi x Co y Mn z O2 (NCM) (where 0 < x < 1, 0 < y < 1, 0 < z < 1 and x + y + z = 1). When the positive electrode active material includes a ternary lithium transition metal oxide having a layered rock salt-type structure, the all-solid-state battery 10 may have an increased energy density and improved thermal stability.

[0055] The oxide-based positive electrode active material may be covered with a coating (not shown). The oxide-based positive electrode active material may be included in a mixture of the above compounds and the compounds added with the coating. The coating added to the surface of the positive electrode active material may include, for example, at least one of oxides, hydroxides, hydroxyoxides, carbonate oxides, and bicarbonates of coating elements discussed below. The compound constituting the coating may be amorphous or crystalline. The coating elements included in the coating may include at least one of Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, and mixtures thereof. The coating may include, for example, Li2O-ZrO2 (LZO). The method for forming the coating may be or include any method that does not have an adverse effect on the physical properties of the positive electrode active material. The method for forming the coating may include, for example, spraying or dipping.

[0056] When the oxide-based positive electrode active material is a ternary lithium transition metal oxide including nickel (Ni) (such as NCA or NCM discussed above), the capacity density of the all-solid-state battery 10 can be increased to reduce metal leaching from the positive electrode active material during the state of charge. Therefore, the all-solid-state battery 10 can improve its cycle characteristics under charge. The term "cycle characteristics" can refer to the properties that indicate the degree of degradation of the all-solid-state battery 10 due to charging and discharging. For example, an all-solid-state battery 10 with high cycle characteristics may degrade less due to charging and discharging, while an all-solid-state battery 10 with low cycle characteristics may degrade more due to charging and discharging.

[0057] Oxide-based positive electrode active materials can have, for example, spherical or elliptical particle shapes. There are no limitations on the particle size and amount of oxide-based positive electrode active materials. Oxide-based positive electrode active materials can have sizes, for example, from about 0.1 μm to about 30 μm, from about 0.5 μm to about 20 μm, or from about 1 μm to about 15 μm. Oxide-based positive electrode active materials can be or include, for example, single-crystal or polycrystalline particles.

[0058] The positive electrode active material layer 120 according to an exemplary embodiment of this disclosure may include a sulfide-based positive electrode active material. For example, the sulfide-based positive electrode active material may include a Li2S-containing positive electrode active material. The Li2S-containing positive electrode active material may include at least one of the following: a complex of Li2S and carbon; a complex of Li2S, carbon, and a solid electrolyte; a complex of Li2S and a solid electrolyte; a complex of Li2S and a lithium salt; a complex of Li2S, a lithium salt, and carbon; a complex of Li2S, a lithium salt, a metal halide, and carbon; a complex of Li2S and a metal carbide; a complex of Li2S, carbon, and a metal carbide; a complex of Li2S and a metal nitride; a complex of Li2S, carbon, and a metal nitride; and combinations thereof.

[0059] solid electrolyte Reference Figure 3 In addition to the positive electrode active material, the positive electrode active material layer 120 according to an exemplary embodiment of this disclosure may also include a solid electrolyte. The solid electrolyte may exhibit lithium-ion conductivity and may be or include a medium through which lithium ions are transferred from the positive electrode active material in the positive electrode 100. The positive electrode active material and the solid electrolyte may exist as separate particles. For example, the positive electrode active material layer 120 may include positive electrode active material particles (CAC) and solid electrolyte particles (SEP).

[0060] When using a conventional liquid electrolyte, the liquid electrolyte can be immersed in the electrode to freely contact the positive electrode active material. However, in the case of an all-solid-state battery, the positive electrode may include a solid electrolyte to improve lithium-ion mobility. Additionally, the electrode may include a conductive material for improving electronic conductivity.

[0061] In the case of a positive electrode for an all-solid-state battery that includes solid electrolyte particles (SEP), the presence of a large number of solid particles in the positive electrode may prevent the conductive material from being uniformly distributed, potentially leading to non-uniform electrode performance. Furthermore, when the electrode is manufactured thicker to increase capacity, the uniformity of the electrode may be further reduced. According to embodiments of this disclosure, the performance of the all-solid-state battery can be enhanced by introducing a solid electrolyte that simultaneously or concurrently improves both electronic and ionic conductivity.

[0062] Reference Figure 4 Solid electrolyte particles (SEPs) can form clusters (CLUs) with positive electrode active material particles (CACs). In this specification, a cluster (CLU) can refer to the state in which SEPs and CACs aggregate or form an aggregate. A cluster (CLU) can represent a group of independent particles that are in physical contact with each other while remaining independent particles. In other words, a cluster (CLU) can represent a group formed by a specific particle together with adjacent particles. For example, a cluster (CLU) can consist of multiple positive electrode active material particles (CACs) and multiple solid electrolyte particles (SEPs), or include multiple positive electrode active material particles (CACs) and multiple solid electrolyte particles (SEPs).

[0063] In example embodiments, such as Figure 4 As shown, a cluster CLU may include a positive electrode active material particle (CAC) and multiple solid electrolyte particles (SEPs). Within the cluster CLU, the positive electrode active material particle (CAC) may be electrically connected to at least one of the multiple solid electrolyte particles (SEPs). Additionally, contacting solid electrolyte particles (SEPs) may be electrically connected to each other. Therefore, the cluster CLU may include an electrical path (ETP). The electrical path (ETP) may include an electrical pathway between the positive electrode active material particle (CAC) and the solid electrolyte particles (SEPs) and / or an electrical pathway between the multiple solid electrolyte particles (SEPs).

[0064] Reference Figure 5 Solid electrolyte particles (SEPs) according to exemplary embodiments of this disclosure may include a linear carbon-based conductive material (CDM) dispersed therein. Because the SEPs include a carbon-based conductive material, they can be conductive.

[0065] For example, a linear carbon-based conductive material (CDM) can be configured to pass through a solid electrolyte particle (SEP). When the CDM passes through the SEP, an electrical path (ETP) can be formed between a first position (LO1) and a second position (LO2) on the surface of the SEP. Adjacent particles can be electrically connected through the ETP in the SEP. The SEP according to exemplary embodiments of this disclosure can simultaneously or concurrently perform ion conduction and electron conduction functions.

[0066] In the example embodiment, the linear carbon-based conductive material of the first solid electrolyte particle SEP1 can form an electrical path ETP between the positive electrode active material particle CAC and the first solid electrolyte particle SEP1. Therefore, the positive electrode active material particle CAC can be electrically connected to the first solid electrolyte particle SEP1.

[0067] In an example embodiment, the second solid electrolyte particle SEP2 can be in contact with the first solid electrolyte particle SEP1. The electrical path ETP can be formed of a linear carbon-based conductive material of the first solid electrolyte particle SEP1 and the second solid electrolyte particle SEP2. Therefore, the first solid electrolyte particle SEP1 and the second solid electrolyte particle SEP2 can be electrically connected to each other.

[0068] In short, such as Figure 6 As shown, the clusters of CLUs in the positive electrode active material layer 120 can form both ion conduction pathways (ITPs) and electrical pathways (ETPs). Therefore, the positive electrode active material layer 120 can improve the mobility of ions and electrons. The positive electrode active material particles (CACs) and solid electrolyte particles (SEPs) can be uniformly mixed to improve electrode uniformity. Electrode performance can also be enhanced, such as reducing resistance and improving rate performance.

[0069] Return to reference Figure 5 Solid electrolyte particles (SEPs) can include a linear carbon-based conductive material (CDM) dispersed therein. For example, a SEP can include a matrix EM formed of or comprising a solid electrolyte, and a linear carbon-based conductive material (CDM) disposed within the matrix EM. The solid electrolyte matrix EM can occupy most of the volume of the SEP and can constitute the basic form of the SEP. The linear carbon-based conductive material (CDM) can have a structure that extends through the solid electrolyte matrix EM. Through the configuration discussed above, the SEP can simultaneously or concurrently function as both an electrolyte and a conductive material.

[0070] The linear carbon-based conductive material (CDM) in solid electrolyte particles (SEPs) can refer to a conductive material with a linear particle shape, such as a conductive material with an aspect ratio (length to diameter) equal to or greater than about 10. The linear carbon-based conductive material (CDM) can have an aspect ratio in the range of about 20 to about 700, about 50 to about 600, about 60 to about 300, or about 100 to about 300. Because the linear carbon-based conductive material (CDM) has an aspect ratio within the above range, it can improve the electronic conductivity of the solid electrolyte particle (SEP) and alleviate local non-uniformity of electronic conductivity in the SEP.

[0071] In an example embodiment, the linear carbon conductive material CDM may include carbon nanotubes (CNT), carbon nanofibers (CNF), vapor-grown carbon fibers (VGCF), or combinations thereof.

[0072] Linear carbon conductive materials (CDMs) can have shapes that extend in one direction, thus enabling the formation of structures that penetrate solid electrolyte particles (SEPs). Since the SEPs comprise linear carbon conductive materials (CDMs), electron conduction can easily occur from the surface of the SEPs to their interior.

[0073] For example, a linear carbon-based conductive material (CDM) can penetrate solid electrolyte particles (SEP) to provide conductive sites on the surface of the SEP. Multiple linear carbon-based conductive materials (CDMs) can be dispersed within the SEP to provide conductive sites on the surface of the SEP. At least one linear carbon-based conductive material (CDM) can be dispersed within the SEP to provide conductive sites on the surface of the SEP. Because multiple conductive sites are formed on the surface of the SEP, SEP particles in contact with each other can be electrically connected. Unlike irregular or spherical conductive materials, the dispersion of linear conductive materials within the SEP allows the SEP to be conductive. As a result, the internal resistance of the positive electrode active material layer 120 can be reduced, and the cycle characteristics of the all-solid-state battery 10 can be improved.

[0074] Linear carbon conductive materials (CDMs) can have diameters ranging from about 2 nm to about 200 nm, about 100 nm to about 200 nm, about 5 nm to about 150 nm, about 50 nm to about 100 nm, about 10 nm to about 50 nm, or about 5 nm to about 30 nm. Linear carbon conductive materials (CDMs) can also have lengths ranging from about 100 nm to about 500 nm, about 100 nm to about 300 nm, about 100 nm to about 1 μm, or about 500 nm to about 2 μm. The length of a linear carbon conductive material (CDM) can be defined as its average particle size.

[0075] In an example embodiment, the solid electrolyte of the solid electrolyte particle (SEP) may include a sulfide-based solid electrolyte. Sulfide-based solid electrolytes may include at least one of the following: Li₂S-P₂S₅; Li₂S-P₂S₅-LiX (where X is or includes 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 (Where m and n are both positive integers, and "Z" is or includes at least one of Ge, Zn, and Ga); Li2S-GeS2; Li2S-SiS2-Li3PO4; Li2S-SiS2-Li p MO q (Where p and q are both positive integers, and "M" is or includes at least one of P, Si, Ge, B, Al, Ga, and In); Li 7-x PS 6-x Cl x (where 0 ≤ x ≤ 2); Li 7-x PS 6-x Br x (where 0 ≤ x ≤ 2); and Li 7-x PS 6-x I x (Where, 0 ≤ x ≤ 2). Sulfide-based solid electrolytes can be prepared by, for example, melt-quenching or mechanical grinding of starting materials such as Li₂S or P₂S₅. Additionally, the resulting product can be heat-treated after the above treatment. The solid electrolyte can be in an amorphous, crystalline, or mixed state of amorphous and crystalline states. The solid electrolyte may include at least one of the constituent elements of the above-mentioned sulfide-based solid electrolytes, namely sulfur (S), phosphorus (P), and lithium (Li). For example, the solid electrolyte may be or include materials containing Li₂S-P₂S₅. When a sulfide-based solid electrolyte includes materials containing Li₂S-P₂S₅ as the solid electrolyte, the molar ratio of Li₂S to P₂S₅ can be in the range of, for example, about 20:80 to about 90:10, about 25:75 to about 90:10, about 30:70 to about 70:30, or about 40:60 to about 60:40.

[0076] Sulfide solid electrolytes may include, for example, sulfide-germanium ore type solid electrolytes represented by chemical formula 1.

[0077] Chemical Formula 1: Li + 12-n-x A n+ X 2- 6-x Y - x In chemical formula 1, A can be or include at least one of P, As, Ge, Ga, Sb, Si, Sn, Al, In, Ti, V, Nb, and Ta; X can be or include at least one of S, Se, and Te; Y can be or include at least one of Cl, Br, I, F, CN, OCN, SCN, and N3; 1 ≤ n ≤ 5 and 0 ≤ x ≤ 2. Sulfide solid electrolytes can be or include, for example, Li 7- x PS 6-x Cl x (where 0≤x≤2), Li 7-x PS 6-x Br x (where 0 ≤ x ≤ 2) and Li 7-x PS 6-x I x (where 0 ≤ x ≤ 2) is at least one of the following silver-germanium sulfide compounds. Sulfide solid electrolytes may be or include one or more silver-germanium sulfide compounds comprising one or more of Li6PS5Cl, Li6PS5Br, and Li6PS5I.

[0078] Optionally, the sulfide-based solid electrolyte may be or may include Li 7-a-c M a PS 6-c X c A sulfide-germanium ore type compound (where 0 ≤ a ≤ 2 and 0 ≤ c ≤ 2). In the above chemical formula, X can be or include at least one of F, Br, Cl, and combinations thereof. M can be or include at least one of scandium (Sc), yttrium (Y), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), arsenic (As), antimony (Sb), bismuth (Bi), and combinations thereof.

[0079] The solid electrolyte particles (SEPs) in the positive electrode active material layer 120 may be the same as or different from the solid electrolyte in the solid electrolyte layer 300. The SEPs in the positive electrode active material layer 120 may have an average particle size (D50) smaller than the average particle size of the solid electrolyte in the solid electrolyte layer 300. For example, the average particle size of the SEPs in the positive electrode active material layer 120 may be equal to or less than about 90%, about 80%, about 70%, about 60%, about 50%, about 40%, about 30%, or about 20% of the average particle size of the solid electrolyte in the solid electrolyte layer 300. In an example embodiment, the average particle size of the SEPs in the positive electrode active material layer 120 may be in the range of about 0.5 μm to about 2 μm.

[0080] In addition, unlike the solid electrolyte particles (SEP) in the positive electrode active material layer 120, the solid electrolyte in the solid electrolyte layer 300 may not include linear carbon-based conductive materials.

[0081] In an example embodiment, the solid electrolyte particles (SEP) in the positive electrode active material layer 120 may be present in an amount ranging from about 10 wt% to about 70 wt%, from about 10 wt% to about 60 wt%, or from about 10 wt% to about 30 wt%. The positive electrode active material particles (CAC) and solid electrolyte particles (SEP) in the positive electrode active material layer 120 may have a weight ratio ranging from about 70:30 to about 90:10. When the above ranges are met, the ionic conductivity and electronic conductivity of the positive electrode can be improved, and the energy density of the all-solid-state battery can also be improved.

[0082] Solid electrolyte particles (SEPs) according to the example embodiment can be manufactured, for example, by the following method. An electrolyte precursor and a linear carbon-based conductive material can be prepared. The above description can also be applied to linear carbon-based conductive materials.

[0083] The electrolyte precursor may include at least one of a sulfur precursor, a phosphorus precursor, and a halide precursor. The sulfur precursor may include, for example, Li₂S. The phosphorus precursor may include, for example, P₂S₅. The halide precursor may be or include a compound of lithium and halides, and may, for example, include LiX, wherein X is or includes a halogen element. In the above chemical formulas, X may be or include at least one of F, Cl, Br, and I. The electrolyte precursor may be pulverized and then provided in powder form. The electrolyte precursor may be mixed in appropriate proportions according to the stoichiometric ratio of the final manufactured solid electrolyte.

[0084] A manufacturing method according to an example embodiment of the present disclosure may include mixing an electrolyte precursor and a linear carbon-based conductive material to obtain a mixture, and then heat-treating the mixture to prepare solid electrolyte particles.

[0085] The mixing of electrolyte precursors and linear carbon-based conductive materials can be achieved, for example, by melt quenching, mechanical grinding, or solvent dispersion mixing, but can include any method capable of uniformly mixing solid particles, and is not limited to the methods discussed above.

[0086] In the example embodiments, the mixing of precursor materials can be carried out in a dry manner without the use of solvents or the like. The mixing method may include mechanical milling. Mechanical milling may include ball milling or jet milling, but this disclosure is not limited thereto.

[0087] Mechanical milling can be performed in a dry manner, for example, for a duration ranging from about 1 hour to about 1,000 hours, from about 1 hour to about 100 hours, or from about 1 hour to about 20 hours under an inert atmosphere. Mechanical milling can be performed, for example, at rotational speeds ranging from about 100 rpm to about 10,000 rpm, from about 150 rpm to about 5,000 rpm, or from about 200 rpm to about 500 rpm under an inert atmosphere. An inert atmosphere can refer to an environment that substantially excludes oxygen. For example, an inert atmosphere can be an environment that includes at least nitrogen, argon, neon, or combinations thereof. The amount of linear carbon-based conductive material present can range from about 1 wt% to about 5 wt% of the total weight of the electrolyte precursor.

[0088] The mixture can then be heat-treated. The heat treatment can be performed at temperatures ranging from about 100°C to about 800°C, about 100°C to about 600°C, about 100°C to about 550°C, about 150°C to about 200°C, or about 450°C to about 550°C. Furthermore, the heat treatment can be performed for a duration ranging from about 2 hours to about 20 hours, about 3 hours to about 15 hours, or about 5 hours to about 10 hours. When the heat treatment is performed within the above temperature and time ranges, the resulting solid electrolyte particles can exhibit improved crystallinity. The heat-treated solid electrolyte particles can have an average particle size ranging from about 0.5 μm to about 2 μm.

[0089] The manufactured solid electrolyte may include a sulfide-based solid electrolyte matrix and a linear carbon-based conductive material dispersed in the matrix. For example, the solid electrolyte particles may have a structure in which the sulfide-based solid electrolyte forms the basic framework and the linear carbon-based conductive material is present therein.

[0090] Sulfide solid electrolytes can be derived from electrolyte precursors. For example, sulfide solid electrolytes can be or include argentite-germanium sulfide compounds, including one or more of Li6PS5Cl, Li6PS5Br, and Li6PS5I. Since electrolyte precursors also include transition metals, sulfide solid electrolytes can be or include argentite-germanium sulfide compounds doped with transition metals.

[0091] Linear carbon-based conductive materials can be configured to penetrate solid electrolyte particles, thereby forming conductive sites on the surface of the solid electrolyte particles. Therefore, an electrical path can be formed between any first location and any second location on the surface of the solid electrolyte particles. Solid electrolyte particles manufactured according to exemplary embodiments of this disclosure can be configured such that the electrical path between the first and second locations is formed by a linear carbon-based conductive material penetrating the solid electrolyte particles. Therefore, solid electrolyte particles having both ionic and electronic conductivity simultaneously or concurrently can be provided.

[0092] adhesive The positive electrode active material layer 120 may also include a binder. The binder may include at least one of, for example, styrene-butadiene rubber (SBR), polytetrafluoroethylene (PTFE), polyvinylidene fluoride, and polyethylene, but this disclosure is not limited thereto, and any suitable material used as a binder in the art may be used. The binder in the positive electrode active material layer 120 may be present in an amount ranging from, for example, from about 0.1 wt% to about 10 wt%, from about 0.5 wt% to about 5 wt%, or from about 0.5 wt% to about 2 wt% of the total weight of the positive electrode active material layer 120. No binder may be provided.

[0093] conductive materials The positive electrode active material layer 120 may also include a conductive material. The conductive material may include, for example, carbon-based materials, metallic materials, or combinations thereof. Metallic materials may include metal powders, metal fibers, or combinations thereof, but this disclosure is not limited thereto; any suitable metallic material used as a conductive material in the art may be used.

[0094] Conductive materials may include carbon. Conductive materials comprising carbon atoms may include, but are not limited to, any material used as a conductive material in the art. For example, conductive materials may include at least one of crystalline carbon, amorphous carbon, and combinations thereof. Conductive materials may include, for example, calcined products of carbon precursors. Conductive materials may include, for example, carbon nanostructures.

[0095] Unlike the linear carbon-based conductive material (CDM) in solid electrolyte particles (SEP), the conductive material can exist independently in the positive electrode active material layer 120. For example, the conductive material can be distinguished from the linear carbon-based conductive material (CDM) in the solid electrolyte particle (SEP).

[0096] In this example, the conductive material may be omitted. Because the conductive material is omitted, the positive electrode active material layer 120 can improve particle density and energy density. Even without the conductive material, the positive electrode can maintain conductivity because the linear carbon-based conductive material CDM is included in the solid electrolyte particles (SEP).

[0097] According to exemplary embodiments of this disclosure, the positive electrode active material layer 120 can have improved mixing uniformity of solid particles therein. Even when the positive electrode active material layer 120 is formed to a thicker thickness, performance consistency can be maintained. Therefore, despite the increased thickness of the positive electrode active material layer 120, particle density, battery capacity, and battery energy density can be improved. In exemplary embodiments, the positive electrode active material layer 120 can have a thickness ranging from about 50 μm to about 2,000 μm, about 80 μm to about 1,000 μm, about 100 μm to about 1,000 μm, or about 200 μm to about 500 μm.

[0098] negative electrode Return to reference Figure 2 The negative electrode 200 may include a negative electrode current collector 210 and a coating 220 on the negative electrode current collector 210. The negative electrode current collector 210 may provide a reference surface on which the coating 220 is disposed. The negative electrode current collector 210 may include a material that does not react with lithium, such as a material that does not form an alloy or compound with lithium. For example, the negative electrode current collector 210 may include at least one metal such as or containing at least one of copper (Cu), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), and nickel (Ni). The negative electrode current collector 210 may have a thickness in the range of, for example, from about 1 μm to about 20 μm, from about 5 μm to about 15 μm, or from about 7 μm to about 10 μm.

[0099] The negative electrode current collector 210 may be formed or comprise one of the aforementioned metals, an alloy of two or more of the aforementioned metals, or a coating material. The negative electrode current collector 210 may have, for example, a plate or foil shape. In an example embodiment, the negative electrode current collector 210 may not be provided.

[0100] Although not shown, the negative electrode current collector 210 according to the example embodiment may include a substrate film and a metal layer disposed on one or opposite sides of the substrate film. The substrate film may include, for example, a polymer. The polymer may be, or include, for example, a thermoplastic polymer. The polymer may include, for example, at least one of polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polybutylene terephthalate (PBT), polyimide (PI), and combinations thereof. The polymer may be a dielectric polymer. Because the substrate film includes a dielectric thermoplastic polymer, it can soften or liquefy to block battery operation in the event of a short circuit, thereby reducing or suppressing a rapid increase in current. The metal layer may include, for example, at least one of copper (Cu), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), and alloys thereof. The negative electrode current collector 210 may additionally include one or both of a metal sheet and a lead terminal. A detailed description of the positive electrode current collector 110 can be applied to the description of the substrate film, metal layer, metal sheet, and lead terminal of the negative electrode current collector 210. Because the negative electrode current collector 210 has such a structure, the negative electrode 200 can have a reduced weight, and therefore, the all-solid-state battery 10 can have an improved energy density.

[0101] Coating 220 may include a first particle and a second particle. Coating 220 may include a metal and carbon. For example, coating 220 may include at least one metal such as or containing at least one of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn). Coating 220 may include at least one of amorphous carbon, crystalline carbon, and porous carbon; for example, coating 220 may include at least one carbon such as or containing at least one of carbon black, acetylene black, furnace black, Ketjen black, and graphene. In an example embodiment, coating 220 may include a mixture of carbon black and silver (Ag).

[0102] In addition to metals and carbon, coating 220 may also include additives. Coating 220 may include at least one additive such as or containing at least one of binders, fillers, coating agents, dispersants, and ionic conductive agents.

[0103] The coating 220 can have a thickness smaller than that of the positive electrode active material layer 120. The coating 220 can have a thickness equal to or less than about 50%, 40%, 30%, 20%, 10%, or 5% of the thickness of the positive electrode active material layer 120. The thickness of the coating 220 can be in the range of, for example, about 1 μm to about 20 μm, about 2 μm to about 10 μm, or about 3 μm to about 7 μm. When the coating 220 has an excessively small or very small thickness, lithium dendrites formed between the coating 220 and the negative electrode current collector 210 may cause the coating 220 to collapse, thereby reducing the cycle characteristics of the all-solid-state battery 10. When the coating 220 has an excessively large or very large thickness, the all-solid-state battery 10 may have a reduced energy density, and the internal resistance of the all-solid-state battery 10 may increase due to the coating 220, thereby reducing the cycle characteristics of the all-solid-state battery 10.

[0104] Although not shown, a carbon layer may be further included to increase the adhesion between the coating 220 and the solid electrolyte layer 300.

[0105] solid electrolyte layer A solid electrolyte layer 300 may be disposed between the positive electrode 100 and the negative electrode 200. The solid electrolyte layer 300 may include a sulfide-based solid electrolyte having a desired or improved lithium-ion conductivity. The solid electrolyte included in the solid electrolyte layer 300 may comprise the same solid electrolyte particles included in the positive electrode active material layer 120 (see...). Figure 3 The materials used in the solid electrolyte layer 300 may be the same as or different from those used in the SEP. For example, the solid electrolyte in the solid electrolyte layer 300 may not include linear carbon-based conductive materials.

[0106] The solid electrolyte layer 300 may include a first solid electrolyte layer 310 and a second solid electrolyte layer 320. The first solid electrolyte layer 310 may be adjacent to the positive electrode 100, and the second solid electrolyte layer 320 may be adjacent to the negative electrode 200.

[0107] Reference Figure 2 The first solid electrolyte layer 310 may include a first solid electrolyte. The first solid electrolyte may have a substantially spherical or elliptical particle shape. The first solid electrolyte may include a sulfide-based solid electrolyte. The first solid electrolyte may be in an amorphous state, a crystalline state, or a mixture of amorphous and crystalline states. Additionally, the first solid electrolyte may include at least one of the constituent elements of sulfur (S), phosphorus (P), and lithium (Li) contained in the aforementioned sulfide-based solid electrolytes. For example, the first solid electrolyte may be or include a material comprising Li₂S-P₂S₅. When Li₂S-P₂S₅ is used as the sulfide-based solid electrolyte material of the first solid electrolyte, the molar ratio of Li₂S to P₂S₅ may be in the range of about 50:50 to about 90:10.

[0108] In an example embodiment, the first solid electrolyte may include a pyrrhotgermanium-type compound, which includes, for example, Li. 7-x PS 6-x Cl x (where 0≤x≤2), Li 7-x PS 6-x Br x (where 0 ≤ x ≤ 2) and Li 7-x PS 6-x I x (where 0 ≤ x ≤ 2). The first solid electrolyte may include a sulforaphite-germanium type compound comprising at least one of Li6PS5Cl, Li6PS5Br, and Li6PS5I.

[0109] Optionally, the first solid electrolyte may include Li 7-a-c M a PS 6-c X c A sulfide-germanium ore type compound. In the above chemical formula, X can be or include at least one of Cl, Br, and combinations thereof. M can be or include at least one of Na, K, Fe, Mg, Ca, Ag, Cu, Zr, Zn, and combinations thereof. Subscripts a and c can both be real numbers between 0 and 2, and can include 0 and 2.

[0110] The first solid electrolyte of the argentite-germanium sulfide type can have a density in the range of about 1.5 g / cc to about 2.0 g / cc. Since the argentite-germanium sulfide type first solid electrolyte has a density equal to or greater than about 1.5 g / cc, it is possible to reduce the internal resistance of the all-solid-state battery 10 and avoid or prevent short circuits and penetration of the solid electrolyte layer 300 due to the formation of lithium dendrites. The first solid electrolyte can have a modulus in the range of, for example, about 15 GPa to about 35 GPa.

[0111] The second solid electrolyte layer 320 may include a second solid electrolyte. The second solid electrolyte may have a substantially spherical or elliptical particle shape. The second solid electrolyte may include a sulfide-based solid electrolyte. The description of the second solid electrolyte may be the same as or similar to that of the first solid electrolyte. In an example embodiment, the second solid electrolyte may have a composition substantially the same as that of the first solid electrolyte. Optionally, the second solid electrolyte may have a composition similar to that of the first solid electrolyte.

[0112] The second solid electrolyte can be in direct contact with the coating 220. Therefore, the second solid electrolyte can suppress lithium dendrites forming between the coating 220 and the negative electrode current collector 210. The second solid electrolyte can effectively reduce or suppress negative electrode side reactions. Therefore, the all-solid-state battery 10 according to this disclosure can improve battery performance.

[0113] Each or at least one of the first solid electrolyte layer 310 and the second solid electrolyte layer 320 may further include an adhesive. The adhesive for the solid electrolyte layer 300 may include at least one of, for example, styrene-butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, and polyethylene, but this disclosure is not limited thereto. The adhesive for the solid electrolyte layer 300 may be the same as or different from the adhesive for the positive electrode active material layer 120 or the adhesive for the coating 220.

[0114] The binder of the solid electrolyte layer 300 may be present in an amount ranging from about 0.1 wt% to about 10 wt%, about 0.1 wt% to about 5 wt%, about 0.1 wt% to about 3 wt%, about 0.1 wt% to about 1 wt%, about 0 wt% to about 0.5 wt%, or about 0 wt% to about 0.1 wt% of the total weight of the solid electrolyte layer 300.

[0115] In the exemplary embodiments of this disclosure, the solid electrolyte layer 300 may be configured as a single-layer structure, rather than a double-layer structure of the first solid electrolyte layer 310 and the second solid electrolyte layer 320.

[0116] Return to reference Figure 1 and Figure 2 The positive electrode 100 and the first solid electrolyte layer 310 can form a positive electrode mixture layer CSH. The negative electrode 200 and the second solid electrolyte layer 320 can form a negative electrode mixture layer ASH. The positive electrode mixture layer CSH can be stacked on the negative electrode mixture layer ASH.

[0117] The negative electrode mixture layer ASH and the positive electrode mixture layer CSH can have different areas. For example, the area of ​​the negative electrode mixture layer ASH can be larger than the area of ​​the positive electrode mixture layer CSH. The positive electrode mixture layer CSH can be completely stacked inward with the negative electrode mixture layer ASH.

[0118] In an exemplary embodiment of this disclosure, the first solid electrolyte layer 310 may have an area substantially the same as that of the positive electrode 100. The second solid electrolyte layer 320 may have an area substantially the same as that of the negative electrode 200.

[0119] For example, the positive electrode hybrid layer CSH may have a first width WI1 in the first direction D1. The negative electrode hybrid layer ASH may have a second width WI2 in the first direction D1. The first width WI1 may be smaller than the second width WI2. The positive electrode hybrid layer CSH may have a third width WI3 in the second direction D2. The negative electrode hybrid layer ASH may have a fourth width WI4 in the second direction D2. In this example, the third width WI3 may be smaller than the fourth width WI4.

[0120] An example of an all-solid-state battery 10 according to this embodiment can be manufactured by forming a negative electrode mixture layer ASH on a first carrier film, forming a positive electrode mixture layer CSH on a second carrier film, and then laminating the negative electrode mixture layer ASH and the positive electrode mixture layer CSH.

[0121] In example embodiments, such as Figure 2 As shown, the positive electrode active material layer 120 in the discharged state may have a first thickness TK1. The all-solid-state battery 10 may have a first height HE1 on the third-direction D3. The first height HE1 may be the sum of the thickness of the positive electrode mixture layer CSH and the thickness of the negative electrode mixture layer ASH.

[0122] In the following example embodiments, references to the above are omitted. Figures 1 to 3 The technical features discussed are repeated in detail, and their differences are discussed in detail.

[0123] Figure 7 It shows along Figure 1 A cross-sectional view taken along line A-A' illustrates an all-solid-state battery according to an exemplary embodiment of the present disclosure. (Refer to...) Figure 7 In an example embodiment, the all-solid-state battery 10 in a charged state may further include a lithium metal layer 230 between the negative electrode current collector 210 and the coating 220. The negative electrode 200 according to the example embodiment may include the negative electrode current collector 210, the coating 220, and the lithium metal layer 230 between the negative electrode current collector 210 and the coating 220.

[0124] The lithium metal layer 230 may comprise lithium or a lithium alloy. Since the lithium metal layer 230 is a metal layer comprising lithium, it can be configured, for example, as a lithium storage device. The lithium alloy may be, for example, a Li-Al alloy, a Li-Sn alloy, a Li-In alloy, a Li-Ag alloy, a Li-Au alloy, a Li-Zn alloy, a Li-Ge alloy, or a Li-Si alloy; however, any suitable material used as a lithium alloy in the art may be applicable. The lithium metal layer 230 may be formed from lithium, one of the aforementioned alloys, or various types of alloys. The lithium metal layer 230 may be, for example, a plating. For example, when the all-solid-state battery 10 is charged, the lithium metal layer 230 may be plated between the coating 220 and the negative electrode current collector 210.

[0125] The lithium metal layer 230 may have a third thickness TK3. The third thickness TK3 may be in the range of, for example, about 1 μm to about 500 μm, about 1 μm to about 200 μm, about 1 μm to about 150 μm, about 1 μm to about 100 μm, or about 1 μm to about 50 μm, but this disclosure is not particularly limited thereto. When the third thickness TK3 of the lithium metal layer 230 is excessively small or very small, the lithium metal layer 230 may be difficult to function as a lithium storage device. When the third thickness TK3 of the lithium metal layer 230 is excessively large or very large, the mass and volume of the all-solid-state battery 10 will increase, and there is a possibility that the cycle characteristics will decrease.

[0126] In embodiments of this disclosure, the lithium metal layer 230 in the negative electrode 200 may be disposed between the negative electrode current collector 210 and the coating 220, for example, before assembling the all-solid-state battery 10. When the lithium metal layer 230 is disposed between the negative electrode current collector 210 and the coating 220 before assembling the all-solid-state battery 10, the lithium metal layer 230 may be a metal layer comprising lithium, and thus can be configured as a lithium storage device. For example, a lithium foil may be disposed between the negative electrode current collector 210 and the coating 220 before assembling the all-solid-state battery 10.

[0127] When the lithium metal layer 230 is deposited by charging after assembling the all-solid-state battery 10, the lithium metal layer 230 is not included during the assembly of the all-solid-state battery 10, thus the all-solid-state battery 10 can have increased energy density. When the all-solid-state battery 10 is charged, charging beyond the charging capacity of the coating 220 can be achieved. For example, the coating 220 can be overcharged. During the initial charge, lithium can be absorbed into the coating 220. When charging beyond the charging capacity of the coating 220 is achieved, lithium can be deposited between the coating 220 and the negative electrode current collector 210. The lithium metal layer 230 can be formed from deposited lithium.

[0128] The lithium metal layer 230 may be primarily formed of lithium (or metallic lithium) or may include lithium (or metallic lithium). During discharge, the lithium in the lithium metal layer 230 can be ionized to move toward the positive electrode 100. For example, lithium can be included as a negative electrode active material in the all-solid-state battery 10. Furthermore, since the coating 220 covers the lithium metal layer 230, the coating 220 can protect the lithium metal layer 230 and also suppress the deposition and growth of lithium dendrites. Therefore, the coating 220 can reduce or suppress short circuits and capacity degradation in the all-solid-state battery 10 and improve the cycle characteristics of the all-solid-state battery 10.

[0129] When a lithium metal layer 230 is formed by charging after assembling the all-solid-state battery 10, the negative electrode 200, or the negative electrode current collector 210, the coating 220, and the area between the negative electrode current collector 210 and the coating 220 may be or include a lithium-free area that does not contain lithium in the initial state or in the state after the all-solid-state battery 10 is fully discharged.

[0130] The positive electrode active material layer 120 that releases lithium ions from the all-solid-state battery 10 during charging can have a second thickness TK2. The second thickness TK2 of the positive electrode active material layer 120 can be less than... Figure 2 The first thickness is TK1.

[0131] In exemplary embodiments of this disclosure, the difference between the first thickness TK1 and the second thickness TK2 can be substantially the same as or similar to the third thickness TK3 of the lithium metal layer 230. For example, the third thickness TK3 can be in the range of about 1.0 to 1.5 times, or about 1 to 1.2 times, the difference between the first thickness TK1 and the second thickness TK2. According to an example of this disclosure, the thickness of the positive electrode active material layer 120 can be correspondingly reduced to be the same as the thickness of the lithium metal layer 230 formed by charging the all-solid-state battery 10.

[0132] Although not shown, the all-solid-state battery 10 can be operated in a pressed state (e.g., charging and / or discharging) using a pressing clamp. In an example embodiment, the all-solid-state battery 10 can be pressed under a pressure ranging from about 0.8 MPa to about 2 MPa. For example, the all-solid-state battery 10 can have an internal pressure of about 1 MPa during discharge and about 1.5 MPa during charging. The ratio of the internal pressure of the all-solid-state battery 10 in the charging state to the internal pressure of the all-solid-state battery 10 in the discharging state can range from about 1.0 to about 2.0 or from about 1.2 to about 1.8.

[0133] The height (or thickness or volume) of the all-solid-state battery 10 can be varied depending on the charging and discharging of the all-solid-state battery 10 in a compressed state. According to an example of this disclosure, the thickness of the positive electrode active material layer 120 in the D3 direction can be reduced correspondingly to the lithium metal layer 230 formed during charging of the all-solid-state battery 10. Therefore, as... Figure 7 The second height HE2 of the all-solid-state battery 10 shown in the charging state can be similar to that of... Figure 2 The all-solid-state battery 10 shown is in a first height HE1 in a discharged state. For example, the second height HE2 can be in the range of about 1 to 1.5 times or about 1 to 1.2 times the first height HE1.

[0134] Figure 8 It shows along Figure 1 A cross-sectional view taken along line A-A' illustrates an all-solid-state battery according to an exemplary embodiment of the present disclosure. (Refer to...) Figure 8 The all-solid-state battery 10 according to this embodiment may further include a gasket GSK. The gasket GSK may be configured to surround the positive electrode mixture layer CSH. The area difference between the negative electrode mixture layer ASH and the positive electrode mixture layer CSH results in a step difference on the side surface of the all-solid-state battery 10, and the gasket GSK may substantially fill this step difference. The gasket GSK may surround, for example, the four side surfaces of the positive electrode mixture layer CSH. For example, the thickness of the gasket GSK in the D3 direction may be substantially the same as the thickness of the positive electrode mixture layer CSH.

[0135] The top surface of the second solid electrolyte layer 320 may include a first region in contact with the first solid electrolyte layer 310 and a second region in contact with the gasket GSK. The second region may be the outer peripheral region of the top surface of the second solid electrolyte layer 320. The second region may surround the first region.

[0136] When manufacturing the all-solid-state battery 10 and / or during charging and discharging, the gasket GSK can prevent or substantially prevent the solid electrolyte layer 300 from cracking. Therefore, the cycle characteristics of the all-solid-state battery 10 can be improved. When the all-solid-state battery 10 does not include the gasket GSK, irregular pressures may be applied to the positive electrode mixture layer CSH and the negative electrode mixture layer ASH, thus the solid electrolyte layer 300 may undergo cracking to induce lithium metal growth, thereby increasing the likelihood of a short circuit.

[0137] The thickness of the gasket GSK in the D3 direction can be substantially equal to or greater than the thickness of the positive electrode mixture layer CSH. Since the thickness of the gasket GSK is the same as the thickness of the positive electrode mixture layer CSH, a uniform pressure can be provided between the positive electrode mixture layer CSH and the negative electrode mixture layer ASH, and they can be brought close enough to each other to reduce the interfacial resistance between the first solid electrolyte layer 310 and the second solid electrolyte layer 320. Furthermore, since the solid electrolyte layer 300 is sufficiently sintered during the pressing process of manufacturing the all-solid-state battery 10, the internal resistance of the solid electrolyte layer 300 can be reduced.

[0138] Gasket GSKs can have, for example, a single-layer structure. Alternatively, although not shown in the figures, gasket GSKs can have a multi-layer structure. In a multi-layer gasket GSK, each layer can have a different composition. Multi-layer gasket GSKs can have two-layer, three-layer, four-layer, or five-layer structures. Multi-layer gasket GSKs can include, for example, at least one adhesive layer and at least one support layer.

[0139] The gasket GSK may include, for example, flame-retardant inactive components. Because the flame-retardant inactive components provide flame retardancy, the possibility of thermal runaway and ignition of the all-solid-state battery 10 can be avoided or substantially prevented. Therefore, the gasket GSK can improve the stability of the all-solid-state battery 10. When the flame-retardant inactive components absorb moisture remaining in the all-solid-state battery 10, the degradation of the all-solid-state battery 10 can be reduced or prevented, thereby improving the cycle characteristics of the all-solid-state battery 10.

[0140] Figure 9 It shows along Figure 1 A cross-sectional view taken along line A-A' illustrates an all-solid-state battery according to an exemplary embodiment of the present disclosure. (Refer to...) Figure 9 The positive electrode 100 may further include a coating CTL disposed between the positive electrode current collector 110 and the positive electrode active material layer 120. The coating CTL may be disposed, for example, on one side or the opposite side of the positive electrode current collector 110. The coating CTL may be coated on one side or the opposite side of the positive electrode current collector 110. In the example, no layer may be disposed between the positive electrode current collector 110 and the coating CTL.

[0141] Since the CTL coating is directly disposed on one or the opposite side of the positive electrode current collector 110, the adhesion between the positive electrode current collector 110 and the positive electrode active material layer 120 can be improved. Because the CTL coating is disposed between the positive electrode current collector 110 and the positive electrode active material layer 120, side reactions between the positive electrode current collector 110 and the filler, solid electrolyte, or positive electrode active material can be effectively reduced or suppressed. For example, the CTL coating can reduce or prevent corrosion of sulfide-based positive electrode active materials (e.g., Li2S) due to the positive electrode current collector 110. Therefore, the CTL coating can reduce or suppress the degradation of the all-solid-state battery 10 during charging and discharging, and can improve the cycle characteristics of the all-solid-state battery 10.

[0142] The thickness of the coating CTL can be, for example, in the range of about 0.01% to about 20%, about 0.1% to about 20%, about 0.5% to about 20%, about 1% to about 15%, about 1% to about 10%, about 2% to about 8%, or about 3% to about 7% of the thickness of the positive electrode current collector 110. The thickness of the coating CTL can be, for example, in the range of about 10 nm to about 5 μm, about 50 nm to about 5 μm, about 200 nm to about 4 μm, about 500 nm to about 3 μm, about 500 nm to about 2 μm, about 500 nm to about 1.5 μm, or about 700 nm to about 1.3 μm. When the thickness of the coating CTL falls within the above ranges, the adhesion between the positive electrode current collector 110 and the positive electrode active material layer 120 can be improved, and the increase in interfacial resistance between the positive electrode current collector 110 and the positive electrode active material layer 120 can be reduced or suppressed. The thickness of the coating CTL can be measured via, for example, a scanning electron microscope (SEM) image of a cross-section of the coating CTL.

[0143] The coating CTL may include, for example, a carbon-based conductive material. The carbon-based conductive material included in the coating CTL may be or include at least one of the carbon-based conductive materials contained in the positive electrode active material layer 120. The coating CTL may include the same carbon-based conductive material as the carbon-based conductive material of the positive electrode active material layer 120. When the coating CTL includes a carbon-based conductive material, the coating CTL may be or include a conductive layer.

[0144] The coating CTL may additionally include, for example, an adhesive. Because the coating CTL additionally includes an adhesive, the adhesion between the positive electrode current collector 110 and the positive electrode active material layer 120 can be improved. The adhesive included in the coating CTL can be, for example, a conductive adhesive or a non-conductive adhesive. The conductive adhesive can be, for example, an ionicly conductive adhesive and / or an electronically conductive adhesive. Adhesives having both ionic and electronic conductivity properties can be classified as both ionicly conductive adhesives and electronically conductive adhesives.

[0145] The binder included in the coating CTL may be or include at least one of the binders used for the positive electrode active material layer 120. The coating CTL may include the same binder as the binder for the positive electrode active material layer 120. The binder included in the coating CTL may be or include, for example, a fluorinated binder. Fluorinated binders included in the coating CTL may include, for example, polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), or combinations thereof. The coating CTL may be or include, for example, an adhesive layer containing a binder. The coating CTL may be or include, for example, a conductive layer containing a binder and a carbon-based conductive material.

[0146] Dry or wet processes can be performed to place the coated CTL onto the positive electrode current collector 110. For example, a dry process such as CVD, PVD, or other suitable deposition process can be performed to place the coated CTL onto the positive electrode current collector 110. For example, a wet process such as spin coating or dip coating can be performed to place the coated CTL onto the positive electrode current collector 110. For example, a deposition process can be performed to deposit a carbon-based conductive material on a substrate, such that the coated CTL can be disposed on the positive electrode current collector 110. The dry-coated coated CTL can be formed of or include a carbon-based conductive material and may not include a binder. For example, a composition including a carbon-based conductive material, a binder, and a solvent can be coated onto the surface of the electrode current collector and dried to place the coated CTL onto the positive electrode current collector 110. The coated CTL can have a single-layer structure or a multilayer structure including multiple layers. The multilayer structure can be a two-layer, three-layer, or four-layer structure.

[0147] The negative electrode 200 may also include a thin layer of TFL between the negative electrode current collector 210 and the coating 220. The thin layer of TFL may be disposed on one side of the negative electrode current collector 210 to form an alloy with lithium.

[0148] Thin-layer TFLs may include, for example, elements capable of forming alloys with lithium. These elements may include, for example, at least one of gold, silver, zinc, tin, indium, silicon, aluminum, and bismuth, but this disclosure is not limited thereto, and any suitable element in the art capable of forming alloys with lithium may be used. Thin-layer TFLs may be formed from one or an alloy of various types of metals discussed above, or may include alloys of one or more types of metals discussed above.

[0149] Since the thin TFL is disposed on one side of the negative electrode current collector 210, the lithium metal layer deposited between the thin TFL and the coating 220 (see...) Figure 7 The coating shape of the 230 can be made flatter, and the cycle characteristics of the all-solid-state battery 10 can be improved.

[0150] The thickness of the thin-film TFL can range, for example, 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. When the thickness of the thin-film TFL is less than about 1 nm, it may be difficult to achieve the performance benefits induced by the thin-film TFL. When the thickness of the thin-film TFL is excessively large or very large, the thin-film TFL may absorb lithium to reduce lithium deposition, thereby reducing the energy density and cycle characteristics of the all-solid-state battery 10. For example, vapor deposition, sputtering, or plating can be performed to form the thin-film TFL on the negative electrode current collector 210, but this disclosure is not limited thereto, and any suitable method in the art capable of forming a thin film can be utilized.

[0151] Figure 10 This is a flowchart illustrating a method for manufacturing a solid electrolyte according to an exemplary embodiment of the present disclosure. Figure 10 In method 1000, operation 1010 includes mixing an electrolyte precursor and a linear carbon-based conductive material to obtain a mixture. For example, the linear carbon-based conductive material includes at least one of carbon nanotubes (CNTs), carbon nanofibers (CNFs), and vapor-grown carbon fibers (VGCFs). In a further example, the electrolyte precursor includes at least one of a sulfur precursor, a phosphorus precursor, and a halide precursor. In another example, the step of mixing the electrolyte precursor and the linear carbon-based conductive material is performed via a ball milling process. Operation 1020 includes heat-treating the mixture to prepare solid electrolyte particles. For example, the linear carbon-based conductive material is configured to penetrate the solid electrolyte particles to form an electrical path between a first site and a second site on the surface of the solid electrolyte particles. In another example, the step of heat-treating the mixture is performed at a temperature in the range of about 100°C to about 800°C. In a further example, the amount of the linear carbon-based conductive material relative to the total weight of the mixture is in the range of about 1 wt% to about 5 wt%.

[0152] The present disclosure will now be discussed in detail through exemplary embodiments. However, these exemplary embodiments are provided as examples to illustrate the present disclosure, and the scope of the present disclosure is not limited to these embodiments.

[0153] Preparation 1: First solid electrolyte An electrolyte precursor and a linear carbon-based conductive material were prepared. For example, Li₂S powder, P₂S₅ powder, and LiCl powder were prepared in stoichiometric proportions as the electrolyte precursor to achieve the composition Li₆PS₅Cl. Vapor-grown carbon fibers (VGCF) with a diameter of 150 nm were prepared as the linear carbon-based conductive material. The electrolyte precursor, the linear carbon-based conductive material, and zirconia spheres with a diameter of approximately 5 mm were introduced into a container and mechanically milled at room temperature under an argon atmosphere for 24 hours to form a mixture. The linear carbon-based conductive material was present at 1 wt% relative to the total weight of the mixture.

[0154] The mixture was introduced into a carbon crucible and heat-treated at approximately 550°C for 8 hours under an argon atmosphere to prepare the first solid electrolyte particles. The particle size of the prepared particles was approximately 0.5 μm.

[0155] Preparation 2: Second solid electrolyte Unlike preparation 1, only the electrolyte precursor is prepared. For example, Li₂S powder, P₂S₅ powder, and LiCl powder are prepared in stoichiometric ratios as electrolyte precursors to achieve the composition of Li₆PS₅Cl. The electrolyte precursor and zirconia spheres with a diameter of approximately 5 mm are introduced into a container and mechanically ground at room temperature under an argon atmosphere for 24 hours to form a mixture.

[0156] The mixture was introduced into a carbon crucible and heat-treated at approximately 500°C for 10 hours under an argon atmosphere to prepare second solid electrolyte particles. The prepared particles had a particle size of approximately 3 μm.

[0157] Preparation 3: Third solid electrolyte Solid electrolyte particles were prepared using the same method as in Preparation 2, except that the grinding conditions were changed. The particle size of the prepared particles was approximately 0.5 μm.

[0158] Example 1-1: Manufacturing of All-Solid-State Batteries Positive electrode: Prepare to form LiNi 0.94 Co 0.04 Mn 0.02 O2 particles with an average particle size of approximately 10 μm were used as the positive electrode active material. First solid electrolyte particles were prepared for preparation 1. Polyvinylidene fluoride-co-hexafluoropropylene (PVdF-HFP) was prepared as a binder. The positive electrode active material, the first solid electrolyte, and the binder were mixed at a weight ratio of 80:19:1 to prepare a composition for forming the positive electrode active material layer.

[0159] The composition for forming the positive electrode active material layer was dry-coated onto a positive electrode current collector formed from an aluminum foil coated with carbon on one side, and then pressed at 130°C and 1 MPa for 10 minutes to manufacture the positive electrode. The thickness of the positive electrode active material layer was approximately 80 μm.

[0160] Negative electrode: A 10 μm thick stainless steel (SUS) sheet was prepared as the negative electrode current collector. Carbon black (CB) particles with an average particle size of approximately 30 nm and silver (Ag) particles with an average particle size of approximately 60 nm were prepared. 4 g of a mixed powder in which carbon black (CB) and silver (Ag) particles were mixed at a weight ratio of 3:1 was introduced into a container, and 4 g of an N-methylpyrrolidone (NMP) solution including 7 wt% polyvinylidene fluoride (PVdF) binder (Kureha #9300) was added to prepare a mixed solution. A slurry was prepared by gradually adding N-methylpyrrolidone (NMP) to the prepared mixed solution while stirring the mixture. The prepared slurry was coated onto a stainless steel (SUS) sheet using a doctor blade coater and dried in air at 80 °C for 10 min, followed by vacuum drying at 40 °C for 10 h to prepare a stack. The prepared stack is cold-rolled to planarize its surface, thereby fabricating a negative electrode with a coating and a negative electrode current collector. The coating thickness is approximately 15 μm. The area of ​​the coating is the same as the area of ​​the negative electrode current collector.

[0161] Solid electrolyte layer: A mixture was prepared by adding 1.5 parts by weight of an acrylic binder to 98.5 parts by weight of the second solid electrolyte prepared according to Preparation 2. An octyl acetate slurry was prepared by adding octyl acetate to the mixture while stirring. The prepared slurry was coated onto a 15 μm thick nonwoven fabric on a 75 μm thick polyethylene terephthalate (PET) substrate using a doctor blade coater, and the coated slurry was dried in air at 80°C for 10 minutes to prepare a stack. The prepared stack was then vacuum dried at 80°C for 2 hours to produce the solid electrolyte layer.

[0162] Assembly of all-solid-state batteries: A solid electrolyte layer was deposited on the negative electrode, and a positive electrode was placed on the solid electrolyte layer. The prepared stack was pressed at 85°C for 30 minutes under a pressure of 500 MPa. The solid electrolyte layer was sintered by pressing to improve battery characteristics. The thickness of the sintered solid electrolyte layer was approximately 45 μm.

[0163] The pressed stack is placed in a bag and vacuum-sealed to manufacture an all-solid-state battery. A portion of the positive electrode current collector and a portion of the negative electrode current collector are extended to the outside of the sealed battery to serve as the positive electrode terminal and the negative electrode terminal, respectively.

[0164] Examples 1-2: Manufacturing of All-Solid-State Batteries The all-solid-state battery was manufactured using the same method as in Example 1-1, except that the positive electrode active material layer was manufactured to have a thickness of approximately 150 μm.

[0165] Examples 1-3: Manufacturing of All-Solid-State Batteries The all-solid-state battery was manufactured using the same method as in Example 1-1, except that the positive electrode active material layer was manufactured to have a thickness of approximately 200 μm.

[0166] Comparative Example 1-1: Manufacturing of All-Solid-State Batteries The third solid electrolyte prepared in Preparation 3 was used as the solid electrolyte particles for the positive electrode, and carbon black was added as a separate conductive material. Except as described above, the all-solid-state battery was manufactured using the same method as in Examples 1-1.

[0167] The positive electrode active material, the third solid electrolyte, the conductive material and the binder are mixed in a weight ratio of 80:18:1:1.

[0168] The thickness of the positive electrode active material layer is approximately 80 μm.

[0169] Comparative Examples 1-2: Manufacturing of All-Solid-State Batteries An all-solid-state battery was fabricated using the same method as in Comparative Example 1-1, except that the positive electrode active material layer was fabricated to have a thickness of approximately 150 μm.

[0170] Comparative Examples 1-3: Manufacturing of All-Solid-State Batteries An all-solid-state battery was fabricated using the same method as in Comparative Example 1-1, except that the positive electrode active material layer was fabricated to have a thickness of approximately 200 μm.

[0171] Evaluation 1: Electrode particle density The positive electrode particle density of all-solid-state batteries according to the examples and comparative examples was measured. The results are listed in Table 1 below.

[0172] Table 1:

[0173] Based on the evaluation results, it can be observed that the particle density in the positive electrode mixture layer according to the embodiments of this disclosure is greater than the particle density in the positive electrode mixture layer according to the comparative example. Specifically, in the comparative example, the increase in the thickness of the positive electrode active material layer leads to a decrease in particle density.

[0174] Evaluation 2: Battery life characteristics The capacity retention and resistance characteristics of the positive electrode mixture layer were evaluated as characteristics of all-solid-state batteries according to the examples and comparative examples.

[0175] Each of the all-solid-state batteries according to the embodiments and comparative examples was charged at 25°C with a constant current of 0.1C to a maximum voltage of 4.25V, then charged at a constant voltage to 0.05C, and then discharged at 0.1C to a cutoff voltage of 2.5V for an initial charge-discharge cycle.

[0176] Subsequently, at a temperature of 25°C, the capacity retention was evaluated by repeating 100 cycles of charging and discharging at 0.1C. The capacity retention represents the comparison between the battery's initial capacity and its capacity after repeated charge-discharge cycles.

[0177] The resistance was measured using a 4-point probe method. The results of the resistance measurements are listed in Table 2 below.

[0178] Table 2:

[0179] Based on the evaluation results, it can be observed that the capacity retention rate in the all-solid-state battery according to the embodiment is greater than that in the all-solid-state battery according to the comparative example. Furthermore, referring to the resistance measurement results, it can be determined that the comparative example shows a rapid increase in resistance as the thickness of the positive electrode active material layer increases, while the positive electrode according to the embodiment exhibits a relatively low rate of resistance increase. This concludes that the solid electrolyte particles of the exemplary embodiments according to this disclosure are electronically conductive and dispersed in the positive electrode, thereby providing a more uniform positive electrode mixture layer.

[0180] According to exemplary embodiments of this disclosure, the positive electrode for an all-solid-state battery can have improved electronic conductivity and reduced resistance, resulting in improved overall electrode performance. Furthermore, uniform electrodes can be manufactured to reduce variations in battery performance and increase the mass production rate of all-solid-state batteries.

Claims

1. A positive electrode for an all-solid-state battery, the positive electrode comprising: Clusters, comprising active material particles and multiple solid electrolyte particles, The plurality of solid electrolyte particles are in contact with the active material particles. At least one of the plurality of solid electrolyte particles includes a linear carbon-based conductive material dispersed within the solid electrolyte particles. The active material particles of the cluster are electrically connected to the first solid electrolyte particle among the plurality of solid electrolyte particles, and In this configuration, the second solid electrolyte particle among the plurality of solid electrolyte particles is in contact with the first solid electrolyte particle to form an electrical path through the linear carbon conductive material of the first solid electrolyte particle and the linear carbon conductive material of the second solid electrolyte particle.

2. The positive electrode according to claim 1, wherein, At least one of the plurality of solid electrolyte particles includes a matrix comprising a sulfide-based solid electrolyte, and The linear carbon-based conductive material is in the matrix.

3. The positive electrode according to claim 2, wherein, The sulfide-based solid electrolyte includes those composed of Li 7-a-c M a PS 6-c X c The term represents a sulfide solid electrolyte of the sulfide type, where 0 ≤ a ≤ 2 and 0 ≤ c ≤ 2. Wherein, X includes at least one of F, Br, and Cl, and M includes at least one of scandium, yttrium, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, technetium, rhenium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, cadmium, mercury, aluminum, gallium, indium, thallium, silicon, germanium, tin, lead, arsenic, antimony, and bismuth.

4. The positive electrode according to claim 1, wherein, The linear carbon-based conductive material includes at least one of carbon nanotubes, carbon nanofibers, and vapor-grown carbon fibers.

5. The positive electrode according to claim 1, wherein, The active material particles include oxide-based positive electrode active materials.

6. The positive electrode according to claim 1, wherein, The weight ratio of the active substance particles to the solid electrolyte particles is in the range of 70:30 to 90:

10.

7. The positive electrode according to claim 1, wherein, The average particle size of each of the plurality of solid electrolyte particles is in the range of 0.5 μm to 2 μm.

8. An all-solid-state battery, the all-solid-state battery comprising: The positive electrode includes a positive electrode current collector and a positive electrode active material layer on the positive electrode current collector; Solid electrolyte layer; as well as negative electrode, The positive electrode active material layer comprises positive electrode active material particles and first solid electrolyte particles. Wherein, the first solid electrolyte particle includes a linear carbon-based conductive material dispersed in the first solid electrolyte particle, and The linear carbon-based conductive material is configured to penetrate the first solid electrolyte particle to form an electrical path between a first position and a second position on the surface of the first solid electrolyte particle.

9. The all-solid-state battery according to claim 8, wherein, The thickness of the positive electrode active material layer is in the range of 80 μm to 1,000 μm.

10. The all-solid-state battery according to claim 8, wherein, The solid electrolyte layer includes second solid electrolyte particles, and The second solid electrolyte particles do not include the linear carbon-based conductive material.

11. The all-solid-state battery according to claim 10, wherein, The average particle size of the first solid electrolyte particle is smaller than the average particle size of the second solid electrolyte particle.

12. The all-solid-state battery according to claim 8, wherein, The amount of the first solid electrolyte particles is in the range of 10 wt% to 30 wt% of the total weight of the positive electrode active material layer.

13. The all-solid-state battery according to claim 8, wherein, The negative electrode includes: Negative electrode current collector; and A coating is applied to the negative electrode current collector. The coating comprises a first particle and a second particle. The first particle comprises at least one of amorphous carbon, crystalline carbon, and porous carbon, and The second particle includes at least one of gold, platinum, palladium, silicon, silver, aluminum, bismuth, tin, and zinc.

14. The all-solid-state battery according to claim 13, further comprising a lithium metal layer between the negative electrode current collector and the coating. in, The lithium metal layer comprises lithium metal or a lithium metal alloy.

15. A method for manufacturing a solid electrolyte, the method comprising the following steps: An electrolyte precursor and a linear carbon conductive material are mixed to obtain a mixture; and The mixture was heat-treated to prepare solid electrolyte particles. The linear carbon-based conductive material is configured to penetrate the solid electrolyte particles to form an electrical path between a first position and a second position on the surface of the solid electrolyte particles.

16. The method according to claim 15, wherein, The linear carbon-based conductive material includes at least one of carbon nanotubes, carbon nanofibers, and vapor-grown carbon fibers.

17. The method according to claim 15, wherein, The step of mixing the electrolyte precursor and the linear carbon-based conductive material is carried out by ball milling.

18. The method according to claim 15, wherein, The electrolyte precursor includes at least one of sulfur precursor, phosphorus precursor and halide precursor.

19. The method according to claim 15, wherein, The step of heat-treating the mixture at a temperature in the range of 100°C to 800°C.

20. The method of claim 15, wherein, The amount of the linear carbon-based conductive material is in the range of 1 wt% to 5 wt% relative to the total weight of the mixture.

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