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

Abstract

A negative electrode for an all-solid-state battery, an all-solid-state battery including the same, and a method of manufacturing a negative electrode for an all-solid-state battery are disclosed. The negative electrode includes a negative electrode current collector and a negative electrode active material layer. The negative electrode active material layer includes a negative electrode active material and a solid electrolyte. The negative electrode active material includes a porous support and silicon (Si). The silicon fills at least a portion of the pores of the porous support.

Description

[0001] This application claims priority and benefit to Korean Patent Application No. 10-2024-0144742, filed on October 22, 2024, with the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference. Technical Field

[0002] Embodiments of this disclosure relate to a negative electrode for an all-solid-state battery, an all-solid-state battery including a negative electrode, and a method of manufacturing a negative electrode. Background Technology

[0003] Recently, there has been active development of high-energy-density and safe batteries 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 given particular emphasis because it is directly related to human life.

[0004] Recently, all-solid-state batteries using solid electrolytes instead of liquid electrolytes have been proposed. Because all-solid-state batteries do not use flammable organic dispersion media, the possibility of fire or explosion is significantly reduced, even in the event of a short circuit. Therefore, compared to lithium-ion batteries using liquid electrolytes, all-solid-state batteries offer significantly improved safety. Summary of the Invention

[0005] Embodiments of this disclosure provide a negative electrode for an all-solid-state battery having excellent electrical conductivity, superior ionic conductivity, and improved lifetime characteristics.

[0006] Embodiments of this disclosure provide a method for manufacturing a negative electrode for an all-solid-state battery having excellent electrical conductivity and superior ionic conductivity.

[0007] According to embodiments of this disclosure, the negative electrode for an all-solid-state battery may include: a negative electrode current collector; and a negative electrode active material layer. The negative electrode active material layer may include a negative electrode active material and a solid electrolyte. The negative electrode active material may include a porous support and silicon (Si). The silicon may fill at least a portion of the pores of the porous support.

[0008] According to embodiments of this disclosure, an all-solid-state battery may include: the negative electrode discussed above; a positive electrode; and a solid electrolyte layer between the negative electrode and the positive electrode.

[0009] According to embodiments of this disclosure, a method for manufacturing a negative electrode for an all-solid-state battery may include the following steps: preparing a negative electrode active material; mixing the negative electrode active material with a solid electrolyte to prepare a negative electrode active material slurry; and coating the negative electrode active material slurry onto a negative electrode current collector. The step of preparing the negative electrode active material may include: preparing a porous support; and subjecting the porous support to a vapor deposition process to form silicon nanoparticles. Attached Figure Description

[0010] The accompanying drawings, together with the specification, illustrate embodiments of the subject matter of this disclosure, and together with the description, serve to explain the principles of the embodiments of the subject matter of this disclosure.

[0011] Figure 1 This is a cross-sectional view showing an all-solid-state battery according to an embodiment of the present disclosure.

[0012] Figure 2 This is a cross-sectional view showing an all-solid-state battery according to an embodiment of the present disclosure.

[0013] Figure 3 This is a plan view illustrating an all-solid-state battery according to an embodiment of the present disclosure.

[0014] Figure 4 This is a cross-sectional view showing an all-solid-state battery according to an embodiment of the present disclosure.

[0015] Figure 5 It is shown Figure 1 A magnified view of part M.

[0016] Figure 6 This is an enlarged view showing the negative electrode active material according to an embodiment of the present disclosure.

[0017] Figure 7 This is a diagram showing X-ray diffraction analysis of a porous carrier and a negative electrode active material according to an embodiment of the present disclosure.

[0018] Figure 8 This is a graph showing the N2 gas adsorption / desorption of a porous support according to an embodiment of the present disclosure.

[0019] Figure 9 This is a diagram illustrating the pore distribution of a porous carrier according to an embodiment of the present disclosure.

[0020] Figure 10 The images show surface SEM and EDX mapping images of a negative electrode according to embodiments of the present disclosure. Detailed Implementation

[0021] To fully understand the structure and effects of the subject matter of this disclosure, some embodiments of the disclosure will be described with reference to the accompanying drawings. However, it should be noted that this disclosure is not limited to the following example embodiments and can be implemented in various suitable forms. Rather, example embodiments are provided merely to disclose the disclosure and to allow those skilled in the art to fully understand its scope.

[0022] In this specification, it will be understood that if (for example, when) an element is referred to as being on another element, then that element may be directly on said other element, or an intervening element may be present between them. In the accompanying drawings, the thickness of some components may be exaggerated to effectively convey the technical content of this disclosure. Throughout the specification, the same reference numerals refer to the same elements.

[0023] Some embodiments described herein will be discussed with reference to sectional views and / or plan views, which serve as idealized example drawings of this disclosure. In the drawings, the thickness of layers and regions may be exaggerated to effectively interpret the technical content of this disclosure. Therefore, the regions shown as examples in the drawings have general characteristics, and the shapes of the regions shown as examples in the drawings are examples of disclosed settings or specific shapes, but do not limit the scope of this disclosure. It will be understood that although the terms “first,” “second,” “third,” etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. The exemplary embodiments explained and illustrated herein include complementary embodiments thereof.

[0024] The terminology used in this specification is for describing various embodiments only and is not intended to limit this disclosure. Unless otherwise specifically stated in this specification, singular expressions may include plural expressions. The term "comprising / including" and / or variations thereof as used in this specification does not exclude the presence or addition of one or more other components.

[0025] In this specification, the term "combination thereof" may refer to mixtures, stacks, complexes, copolymers, alloys, blends, or reaction products.

[0026] In this specification, each of the phrases such as “A or B”, “at least one of A and B (species / man)”, “at least one of A or B (species / man)”, “A, B or C”, “at least one of A, B and C (species / man)” and “at least one of A, B or C (species / man)” may include any one or all possible combinations of the items listed together in the corresponding one of the phrases.

[0027] Unless otherwise specifically defined in this specification, particle size may be the average particle size. In the embodiments, particle size refers to the average particle size (D) of particles that constitute approximately 50% by volume of the cumulative volume in the particle size distribution. 50Average particle size (D) 50 The particle size can be measured by any suitable method commonly used in the art (e.g., by a particle size analyzer, transmission electron microscopy (TEM) images, and / or scanning electron microscopy (SEM) images). In an embodiment, data analysis is performed using a dynamic light scattering measurement device to count the number of particles for each particle size range, from which the average particle size (D) can be calculated. 50 The average particle size (D) value can be measured using laser scattering methods in this embodiment. 50 In laser scattering, target particles are dispersed in a dispersion solvent and introduced into a laser scattering particle measuring device (e.g., the MT3000 commercially available from Microtrac). The particles are irradiated with 28 kHz ultrasound at 60 W power. The average particle size (D) can then be calculated using a 50% particle size distribution standard within the measuring device. 50 ).

[0028] Figure 1 A cross-sectional view of an all-solid-state battery 10 according to an embodiment of the present disclosure is shown.

[0029] Reference Figure 1 The all-solid-state battery 10 may include a positive electrode layer 100, a negative electrode layer 200 opposite to the positive electrode layer 100, and a solid electrolyte layer 300 between the positive electrode layer 100 and the negative electrode layer 200. However, this disclosure is not limited thereto, and the all-solid-state battery 10 may further include additional functional layers, such as an adhesion enhancement layer, between the positive electrode layer 100 and the solid electrolyte layer 300 and / or between the negative electrode layer 200 and the solid electrolyte layer 300.

[0030] The positive electrode layer 100 according to an embodiment 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, a solid electrolyte, a conductive material (e.g., an electrically conductive material), and a binder.

[0031] 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 plates and / or foils, which include, for example, indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li) and / or alloys thereof.

[0032] and Figure 1As shown in the embodiments of this disclosure, the positive electrode current collector 110 may not be provided. In an embodiment, in order to increase the adhesion between the positive electrode current collector 110 and the positive electrode active material layer 120, a carbon layer with a thickness of about 0.1 μm to about 4 μm may be further provided between the positive electrode current collector 110 and the positive electrode active material layer 120.

[0033] The positive electrode active material layer 120 may include a positive electrode active material, a solid electrolyte, a conductive material (e.g., an electrically conductive material), and a binder.

[0034] The positive electrode active material can be a material capable of reversibly inserting and deintercalating lithium ions. For example, the positive electrode active material may include lithium transition metal oxides (e.g., lithium cobalt oxide (LCO), lithium nickel oxide, lithium nickel cobalt oxide, lithium nickel cobalt aluminum oxide (NCA), lithium nickel cobalt manganese oxide (NCM), lithium manganese oxide, and / or lithium iron phosphate), nickel sulfide, copper sulfide, lithium sulfide, iron oxide, and / or vanadium oxide, but this disclosure is not limited thereto. The positive electrode active material may be used alone or in a mixture of two or more substances.

[0035] Lithium transition metal oxides can be compounds represented, for example, by one of the following: Li a A 1-b B b D2 (where 0.90 ≤ a ≤ 1 and 0 ≤ b ≤ 0.5); Li a E 1-b B b O 2-c D c (Where, 0.90≤a≤1, 0≤b≤0.5, and 0≤c≤0.05); LiE 2-b B b O 4-c D c (Where, 0 ≤ b ≤ 0.5 and 0 ≤ c ≤ 0.05); Li a Ni 1-b-c Co b B c D α (Where, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05 and 0<α<2); Li a Ni 1-b-c Co b B c O 2-α F α (Where, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05 and 0<α<2); Li a Ni 1-b-c Mn b B c Dα (Where, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05 and 0<α≤2); Li a Ni 1-b-c Mn b B c O 2-α F α (Where, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05 and 0<α<2); Li a Ni b E c G d O2 (where 0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5 and 0.001≤d≤0.1); Li a Ni b Co c Mn d G e O2 (where 0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5 and 0.001≤e≤0.1); Li a NiG b O2 (where 0.9 ≤ a ≤ 1 and 0.001 ≤ b ≤ 0.1); Li a CoG b O2 (where 0.90≤a≤1 and 0.001≤b≤0.1); Li a MnG b O2 (where 0.90≤a≤1 and 0.001≤b≤0.1); Li a Mn2G b O4 (where 0.90≤a≤1 and 0.001≤b≤0.1); QO2; QS2; LiQS2; V2O5; LiV2O5; LiIO2; LiNiVO4; Li 3-f J2(PO4)3 (where 0≤f≤2); Li 3-f Fe2(PO4)3 (where 0≤f≤2); and LiFePO4. In the above compounds, "A" can be Ni, Co, Mn or a combination thereof; "B" can be Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements or a combination thereof; "D" can be O, F, S, P or a combination thereof; "E" can be Co, Mn or a combination thereof; "F" can be F, S, P or a combination thereof; "G" can be Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V or a combination thereof; "Q" can be Ti, Mo, Mn or a combination thereof; "I" can be Cr, V, Fe, Sc, Y or a combination thereof; and "J" can be V, Cr, Mn, Co, Ni, Cu or a combination thereof.

[0036] The positive electrode active material may include, for example, a lithium salt of a transition metal oxide having a layered rock salt-type structure (e.g., the structure of layered rock salts) 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 a cubic rock salt-type structure (e.g., the structure of cubic rock salts), where each atom layer forms a two-dimensional plane. The term "cubic rock salt-type structure" may refer to a sodium chloride (NaCl)-type (e.g., class) structure as one of (e.g., a class of) crystal structures, and for example, has a face-centered cubic lattice (FCC) formed by cations and anions, respectively, with each shifted by 1 / 2 of the edge 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) and / or LiNi x Co y Mn z O2 (NCA) (where , , and ). If (e.g., 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.

[0037] The compound included in the positive electrode active material may be covered with a coating. The positive electrode active material may be used as a mixture of the compound and the compound added with the coating. The coating added to the surface of the positive electrode active material may include, for example, oxides, hydroxides, oxyhydroxides, carbonate oxy-salts, and / or bicarbonate salts of the coating elements discussed below. The compound constituting the coating may be amorphous and / or crystalline. The coating elements included in the coating may include Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, or a mixture thereof. The coating may include, for example, Li2O-ZrO2 (LZO). The method for forming the coating may be selected within any suitable method that does not adversely affect the physical properties of the positive electrode active material. The method for forming the coating may include, for example, spraying and / or dipping.

[0038] If (for example, when) the positive electrode active material is a ternary lithium transition metal oxide (such as NCA and / or NCM) including nickel (Ni), 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 charging state. Therefore, the all-solid-state battery 10 can improve its cycle characteristics under charging conditions. The term "cycle characteristics" can refer to a property indicating the degree of degradation of the all-solid-state battery 10 due to charging and discharging. For example, an all-solid-state battery 10 with high cycle characteristics may degrade less due to charging and discharging, while an all-solid-state battery 10 with low cycle characteristics may degrade more due to charging and discharging.

[0039] The positive electrode active material can have a particle shape, for example, spherical or elliptical (e.g., approximately spherical or elliptical). There are no limitations on the particle size and amount of the positive electrode active material.

[0040] Solid electrolytes can have a particulate shape. Solid electrolytes can be dispersed between the positive electrode active materials. Solid electrolytes can include sulfide-based solid electrolytes with excellent lithium-ion conductivity. Sulfide-based solid electrolytes can include, for example, at least one selected from the following: Li₂S-P₂S₅; Li₂S-P₂S₅-LiX (where X is a halogen element); Li₂S-P₂S₅-Li₂O; Li₂S-P₂S₅-Li₂O-LiI; Li₂S-SiS₂; Li₂S-SiS₂-LiI; Li₂S-SiS₂-LiBr; Li₂S-SiS₂-LiCl; Li₂S-SiS₂-B₂S₃-LiI; Li₂S-SiS₂-P₂S₅-LiI; Li₂S-B₂S₃; Li₂S-P₂S₅-Z m S n (Where m and n are both positive integers, and "Z" is chosen from 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 chosen from 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).

[0041] Sulfide solid electrolytes can include, for example, those derived from Li 7-x PS6-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 The compound can be a sulfide-germanium ore type compound selected from at least one of Li6PS5Cl, Li6PS5Br and Li6PS5I. For example, the sulfide solid electrolyte can be a sulfide-germanium ore type compound selected from at least one of Li6PS5Cl, Li6PS5Br and Li6PS5I.

[0042] In the embodiments, the sulfide-based solid electrolyte may include Li 7-a M a PS 6-c X c (Where 0≤a≤2 and 0≤c≤2) are sulfosilver germanite-type compounds. In the above chemical formulas, X can be F, Br, Cl, or a combination thereof. M can be scandium (Sc), yttrium (Y), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), arsenic (As), antimony (Sb), bismuth (Bi), or a combination thereof.

[0043] In an embodiment, the solid electrolyte may be the same as the solid electrolyte included in the solid electrolyte layer 300, which will be discussed further below.

[0044] The sulfide-germanium ore type solid electrolyte can have a density of about 1.5 g / cc to about 2.0 g / cc. Because the sulfide-germanium ore type solid electrolyte has a density equal to or greater than about 1.5 g / cc, it is possible to reduce the internal resistance (e.g., electrical resistance) of the all-solid-state battery and prevent short circuits and penetration of the solid electrolyte layer due to lithium dendrite formation (or reduce the likelihood, incidence, or extent of short circuits and penetration). The solid electrolyte can have an elastic modulus, for example, from about 15 GPa to about 35 GPa.

[0045] The solid electrolyte included in the positive electrode active material layer 120 can have an average particle size (D) that is more moderate than that of the solid electrolyte included in the solid electrolyte layer 300. 50Small to medium-sized average particle size (D) 50 For example, the average particle size (D) of the solid electrolyte in the positive electrode active material layer 120 is of moderate size. 50 The average particle size (D) of the solid electrolyte included in the solid electrolyte layer 300 can be equal to or smaller than the average particle size of the solid electrolyte. 50 Approximately 90%, 80%, 70%, 60%, 50%, 40%, 30%, or 20% of the average particle size (D) of medium-sized particles. 50 The median diameter can be measured using a laser-type particle size distribution analyzer.

[0046] The positive electrode active material layer 120 may include a conductive material (e.g., an electrically conductive material). The conductive material may be conductive (e.g., electrical conductivity) without causing chemical changes (e.g., undesirable chemical changes) in the all-solid-state battery 10, thereby increasing the conductivity (e.g., electrical conductivity) of the positive electrode active material and the solid electrolyte.

[0047] Conductive materials may include carbon-based materials. Conductive materials may include one or more selected from, for example, graphite, carbon black, acetylene black, carbon nanofibers, and carbon nanotubes.

[0048] The positive electrode active material layer 120 may include an adhesive. The adhesive may include a material that causes the positive electrode active material, solid electrolyte, and conductive material included in the positive electrode active material layer 120 to adhere to each other and improves the adhesion between the positive electrode active material layer 120 and the positive electrode current collector 110. The adhesive may include at least one selected from, for example, polyvinylidene fluoride, styrene-butadiene rubber (SBR), polytetrafluoroethylene, vinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, polymethyl methacrylate, and butyl acrylate.

[0049] Based on a total of 100 parts by weight of the positive electrode active material, solid electrolyte, conductive material, and binder, the positive electrode active material may be included in the positive electrode active material layer 120 in an amount of about 85 parts by weight to about 92 parts by weight. Based on a total of 100 parts by weight of the positive electrode active material, solid electrolyte, conductive material, and binder, the binder may be included in the positive electrode active material layer 120 in an amount of about 0.5 parts by weight to about 1.5 parts by weight.

[0050] Based on 100 parts by weight of solid electrolyte, conductive material may be included in the positive electrode active material layer 120 in an amount from about 1 part by weight to about 50 parts by weight. If (e.g., when) the conductive material is included in an amount less than about 1 part by weight relative to 100 parts by weight of solid electrolyte, the proportion of conductive material may decrease, thereby reducing the conductivity of the positive electrode active material layer 120. If (e.g., when) the conductive material is included in an amount greater than about 50 parts by weight relative to 100 parts by weight of solid electrolyte, the proportion of conductive material may increase significantly, resulting in incomplete formation of the coating covering the surface of the solid electrolyte.

[0051] In addition to the positive electrode active material, solid electrolyte, conductive material and binder, the positive electrode active material layer 120 may also include additives such as fillers, coating agents, dispersants and ionic conductive agents.

[0052] Still refer to Figure 1 The negative electrode layer 200 may include a negative electrode current collector 210 and a negative electrode active material layer 220 on the negative electrode current collector 210. The negative electrode active material layer 220 may include a negative electrode active material and a solid electrolyte.

[0053] The negative electrode current collector 210 can provide a reference surface on which the negative electrode active material layer 220 is disposed. The negative electrode current collector 210 may include materials that do not react with lithium, such as materials that do not form alloys or compounds with lithium. Materials included in the negative electrode current collector 210 may include, for example, copper (Cu), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), and / or nickel (Ni), but this disclosure is not limited thereto, and any suitable material may be applicable as long as it is used as an electrode current collector. The negative electrode current collector 210 may have a thickness of about 1 μm to about 20 μm, for example, about 5 μm to about 15 μm, or about 7 μm to about 10 μm.

[0054] The negative electrode current collector 210 may be formed from 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 and / or foil shape. In embodiments, the negative electrode current collector 210 may not be provided.

[0055] The following will refer to Figure 4 and Figure 5 The negative electrode active material layer 220 will be discussed in more detail.

[0056] A solid electrolyte layer 300 may be disposed between the positive electrode layer 100 and the negative electrode layer 200. The solid electrolyte layer 300 may include a sulfide-based solid electrolyte with excellent lithium-ion conductivity. The solid electrolyte included in the solid electrolyte layer 300 may be the same as or different from the solid electrolyte included in the positive electrode active material layer 120.

[0057] In embodiments, the solid electrolyte included in the solid electrolyte layer 300 may be in an amorphous, crystalline, or mixed state of amorphous and crystalline states. The solid electrolyte may include at least sulfur (S), phosphorus (P), and lithium (Li) among the constituent elements of the aforementioned sulfide-based solid electrolytes. For example, the solid electrolyte may be a material comprising Li₂S-P₂S₅. If (for example, when) Li₂S-P₂S₅ is used as the sulfide-based solid electrolyte material of the solid electrolyte, the molar ratio of Li₂S and P₂S₅ may be in the range of about 50:50 to about 90:10.

[0058] Sulfide solid electrolytes can include, for example, those derived from Li 7-x PS 6-x Cl x (where 0≤x≤2), Li 7-x PS 6- x Br x (where 0 ≤ x ≤ 2) and Li 7-x PS 6-x I x The compound can be a sulfide-germanium ore type compound selected from at least one of Li6PS5Cl, Li6PS5Br and Li6PS5I. For example, the sulfide solid electrolyte can be a sulfide-germanium ore type compound selected from at least one of Li6PS5Cl, Li6PS5Br and Li6PS5I.

[0059] In the embodiments, the sulfide-based solid electrolyte may include Li 7-a M a PS 6-c X c(Where 0≤a≤2 and 0≤c≤2) are sulfosilver-germanium minerals. In the above chemical formulas, X can be F, Br, Cl, or a combination thereof. M can be scandium (Sc), yttrium (Y), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), arsenic (As), antimony (Sb), bismuth (Bi), or a combination thereof.

[0060] The sulfide-germanium ore type solid electrolyte can have a density of about 1.5 g / cc to about 2.0 g / cc. Because the sulfide-germanium ore type solid electrolyte has a density equal to or greater than about 1.5 g / cc, it is possible to reduce the internal resistance (e.g., electrical resistance) of the all-solid-state battery and prevent short circuits and penetration of the solid electrolyte layer due to lithium dendrite formation (or reduce the likelihood, incidence, or extent of short circuits and penetration). The solid electrolyte can have a modulus, for example, from about 15 GPa to about 35 GPa.

[0061] The solid electrolyte layer 300 may also include a binder. The binder included in the solid electrolyte layer 300 may include, for example, styrene-butadiene rubber (SBR), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), and / or polyethylene, but this disclosure is not limited thereto. For example, the binder may include at least one selected from styrene-butadiene rubber, PTFE, PVDF, polyethylene, polyvinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, and polymethyl methacrylate. The binder of the solid electrolyte layer 300 may be the same as or different from the binder of the positive electrode active material layer 120 or the binder of the negative electrode active material layer 220.

[0062] Figure 2 This is a cross-sectional view showing an all-solid-state battery 10 according to an embodiment of the present disclosure.

[0063] Reference Figure 2 The solid electrolyte layer 300 may include a first solid electrolyte layer 310 and a second solid electrolyte layer 320. The first solid electrolyte layer 310 may be adjacent to the positive electrode layer 100, and the second solid electrolyte layer 320 may be adjacent to the negative electrode layer 200.

[0064] The first solid electrolyte layer 310 and the second solid electrolyte layer 320 may have different thicknesses. The first solid electrolyte layer 310 may have a first thickness TK1, and the second solid electrolyte layer 320 may have a second thickness TK2. The first thickness TK1 may be greater than the second thickness TK2. For example, the first thickness TK1 may be about 2 to about 100 times the second thickness TK2 (e.g., multiples of 2 to 100).

[0065] Figure 3 This is a plan view showing an all-solid-state battery 10 according to an embodiment of the present disclosure. Figure 4 It shows along Figure 3 A cross-sectional view taken along line A-A'. In the following embodiments, the reference above may not be repeated here. Figure 1 and Figure 2 The technical features discussed will be described in detail, and their differences will be discussed in more detail.

[0066] Reference Figure 3 and Figure 4 The areas of the positive electrode layer 100 and the negative electrode layer 200 can be different from each other. For example, the area of ​​the negative electrode layer 200 can be larger than the area of ​​the positive electrode layer 100. The positive electrode layer 100 can be completely stacked inward with the negative electrode layer 200.

[0067] In embodiments of this disclosure, the first solid electrolyte layer 310 may have an area substantially the same as that of the positive electrode layer 100. The second solid electrolyte layer 320 may have an area substantially the same as that of the negative electrode layer 200.

[0068] For example, the first solid electrolyte layer 310 may have a first width WI1 in the first direction D1. The second solid electrolyte layer 320 may have a second width WI2 in the first direction D1. The first width WI1 may be smaller than the second width WI2. The first solid electrolyte layer 310 may have a third width WI3 in the second direction D2. The second solid electrolyte layer 320 may have a fourth width WI4 in the second direction D2. The third width WI3 may be smaller than the fourth width WI4.

[0069] The all-solid-state battery 10 according to this embodiment can be manufactured by forming a first stack of a positive electrode layer 100 and a first solid electrolyte layer 310, forming a second stack of a negative electrode layer 200 and a second solid electrolyte layer 320, and then laminating the first stack and the second stack.

[0070] Figure 5 The diagram shows a cross-section of the negative electrode for an all-solid-state battery according to an embodiment. Figure 1 An enlarged view of part M depicted in the image. Figure 6An enlarged view of the negative electrode active material according to an embodiment is shown.

[0071] Reference Figure 5 and Figure 6 The negative electrode active material layer 220 according to the embodiment may include a negative electrode active material AAM. The negative electrode active material AAM may include a porous carrier PM and a silicon SNP.

[0072] Silicon SNPs can fill at least a portion of the pores PR in a porous carrier PM. Silicon particles can cause volume expansion during charging, which can be a major cause of negative electrode degradation. According to embodiments of this disclosure, when silicon SNPs fill the pores PR of the porous carrier PM, the volume expansion of silicon can be mitigated. For example, the porous carrier PM can mitigate (or suppress or reduce) the volume expansion of silicon SNPs to improve the lifetime characteristics of the all-solid-state battery. In embodiments, the porous carrier PM can be used to control the particle size of the silicon SNPs. The size and shape of the pores PR of the porous carrier PM can be controlled to adjust the size and shape of the silicon SNPs formed in the pores PR. For example, the all-solid-state battery has a first height in a discharged state, a second height in a charged state, and the ratio of the second height to the first height can be in the range of about 1.1 to about 1.5.

[0073] Porous carriers (PMs) may include, but are not particularly limited to, materials capable of reversibly inserting and de-inserting lithium ions, lithium metal, lithium metal alloys, materials capable of being doped and de-doped with lithium, and / or transition metal compounds.

[0074] For example, the porous support PM can include carbon-based materials that can reversibly insert and deintercalate lithium ions. Carbon-based materials can include crystalline graphite and / or amorphous carbon, such as amorphous hard carbon. Because hard carbon exhibits minimal volume expansion during charging and discharging and demonstrates excellent electrical conductivity and lithium-ion mobility, if (e.g., when) the porous support PM includes hard carbon, it can be possible to suppress or reduce the volume expansion of silicon and improve electrical and ionic conductivity.

[0075] According to embodiments of this disclosure, the porous support PM may include hard carbon exhibiting a peak at about 20° to about 26° in a 2θ-based XRD spectrum. If (for example, when) the porous support PM includes the aforementioned hard carbon, the negative electrode active material AAM can possess excellent ionic conductivity and excellent electrical conductivity.

[0076] According to embodiments of this disclosure, the porous carrier PM may include at least one pore PR. At least a portion of the pore PR may be filled with silicon SNP particles.

[0077] The pore PR of a porous carrier PM can include micropores. The pore PR of a porous carrier PM can also include one or more types selected from mesopores and macropores. The volume occupied by micropores in the porous carrier PM can range from about 50% to about 98%, about 60% to about 95%, or about 70% to about 95% of the total pore volume. If (e.g., when) the volume fraction of micropores in the total pore volume falls within the above range, the particle size of silicon can be appropriately or adequately adjusted, and excellent ionic conductivity and electrical conductivity can be achieved.

[0078] In this specification, a micropore can refer to a pore with a diameter equal to or less than about 2 nm, a mesopore can refer to a pore with a diameter of about 2 nm to about 50 nm, and a macropore can refer to a pore with a diameter equal to or greater than about 50 nm.

[0079] In some embodiments of this disclosure, the porous carrier PM unfilled with silicon SNPs can have a diameter of approximately 1m. 2 / g to approximately 2,000m 2 / g, approximately 300m 2 / g to approximately 1,800m 2 / g or approximately 500m 2 / g to approximately 1,500m 2 Specific surface area (BET) per g.

[0080] In some embodiments of this disclosure, pore size and specific surface area can be measured using the Barrett-Joyner-Halenda (BJH) method and / or calculated using nonlinear density functional theory (NLDFT) methods via N2 adsorption / desorption isotherms. For example, the porous carrier PM can be subjected to a pretreatment process in which the porous carrier PM is heated to 523 K at a rate of 10 K / min, then held at that temperature for 2 to 10 hours at a pressure of 100 mmHg or lower, and in liquid nitrogen at a relative pressure (P / P0) controlled to be below 0.01 Torr up to 10 g / cm³. 3 STP was adsorbed at a single point and then re-adsorbed at 32 points up to 0.955 Torr. Subsequently, nitrogen desorption was performed at 24 points up to a relative pressure of 0.14 Torr to measure pore size and specific surface area. Micropore diameter and specific surface area were measured from relative pressures below 0.01 Torr (P / P0) up to 0.01 Torr at 10 g / cm³. 3 The adsorption of nitrogen at a single point on the STP can be measured within the range where excess nitrogen (N2) can be adsorbed starting from a relative pressure of 0.01 Torr or higher, and the specific surface area can be calculated from the amount of N2 measured using this method relative to the volume of the porous carrier PM.

[0081] The average particle size (D) of porous carrier PM 50 The average particle size can be in the range of about 1 μm to about 50 μm, about 1 μm to about 30 μm, or about 5 μm to about 30 μm. The average particle size can be the median diameter measured using a laser-type particle size distribution analyzer. If (for example, when) the average particle size of the porous carrier PM falls within the above range, the negative electrode active material AAM can exhibit excellent lithium-ion conductivity and superior conductivity.

[0082] Return to reference Figure 6 The silicon SNP can fill at least a portion of the pores PR in the porous carrier PM. For example, the silicon SNP can fill only a portion of the pores PR in the porous carrier PM or can substantially completely fill the pores PR. In embodiments, the silicon SNP can also be formed on the surface of the porous carrier PM. A vapor deposition method can be used to form the silicon SNP on the porous carrier PM. The vapor deposition method will be discussed in more detail in conjunction with methods for fabricating negative electrodes for all-solid-state batteries. In embodiments, the silicon SNP formed on the porous carrier PM can have a nanoparticle shape and can be elemental silicon.

[0083] The silicon SNP may be present in an amount of about 20 wt% to about 80 wt% or about 30 wt% to about 70 wt% relative to the total amount of the negative electrode active material AAM (100 wt%). If (for example, when) the amount of silicon SNP included in the negative electrode active material AAM falls within the above range, improved cycle life characteristics and reduced expansion properties can be achieved.

[0084] The negative electrode active material AAM according to the embodiment or the porous carrier PM in which silicon SNPs are formed in at least a portion of the pores PR can show Si (101) peaks in the 2θ range between 15° and 35° in the XRD spectrum.

[0085] Return to reference Figure 1 and Figure 5 The negative electrode active material layer 220 may further include a solid electrolyte SE. The solid electrolyte SE may have a particulate shape, and the average particle size of the solid electrolyte SE may be smaller than the average particle size of the negative electrode active material AAM. If (for example, when) the size of the solid electrolyte SE is smaller than the size of the negative electrode active material AAM, the solid electrolyte SE may be dispersed between the negative electrode active materials AAM to reduce the porosity of the negative electrode active material layer 220.

[0086] Solid electrolytes (SEs) can include sulfide-based solid electrolytes with excellent lithium-ion conductivity. Sulfide-based solid electrolytes can include, for example, at least one selected from the following: Li₂S-P₂S₅; Li₂S-P₂S₅-LiX (where X is a halogen element); Li₂S-P₂S₅-Li₂O; Li₂S-P₂S₅-Li₂O-LiI; Li₂S-SiS₂; Li₂S-SiS₂-LiI; Li₂S-SiS₂-LiBr; Li₂S-SiS₂-LiCl; Li₂S-SiS₂-B₂S₃-LiI; Li₂S-SiS₂-P₂S₅-LiI; Li₂S-B₂S₃; Li₂S-P₂S₅-Z m S n (Where m and n are both positive integers, and "Z" is chosen from 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 chosen from 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).

[0087] Sulfide solid electrolytes can include, for example, those derived from Li 7-x PS 6-x Cl x (where 0≤x≤2), Li 7-x PS 6- x Br x (where 0 ≤ x ≤ 2) and Li 7-x PS 6-x I x The compound can be a sulfide-germanium ore type compound selected from at least one of Li6PS5Cl, Li6PS5Br and Li6PS5I. For example, the sulfide solid electrolyte can be a sulfide-germanium ore type compound selected from at least one of Li6PS5Cl, Li6PS5Br and Li6PS5I.

[0088] In the embodiments, the sulfide-based solid electrolyte may include Li 7-a M a PS 6-c X c(Where 0≤a≤2 and 0≤c≤2) are sulfosilver germanite-type compounds. In the above chemical formulas, X can be F, Br, Cl, or a combination thereof. M can be scandium (Sc), yttrium (Y), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), arsenic (As), antimony (Sb), bismuth (Bi), or a combination thereof.

[0089] The solid electrolyte SE included in the negative electrode active material layer 220 can have a more moderate average particle size (D) than the solid electrolyte included in the solid electrolyte layer 300. 50 Small to medium-sized average particle size (D) 50 For example, the average particle size (D) of the solid electrolyte SE in the negative electrode active material layer 220 is of moderate size. 50 The average particle size (D) of the solid electrolyte included in the solid electrolyte layer 300 can be equal to or smaller than the average particle size of the solid electrolyte. 50 Approximately 90%, 80%, 70%, 60%, 50%, 40%, 30%, or 20% of the average particle size (D) of medium-sized particles. 50 The median diameter can be measured using a laser-type particle size distribution analyzer.

[0090] The negative electrode active material layer 220 may also include a conductive material (e.g., an electrically conductive material). The conductive material may have conductivity (e.g., electrical conductivity) without causing chemical changes (e.g., undesirable chemical changes) in the all-solid-state battery 10 to increase the conductivity (e.g., electrical conductivity) of the negative electrode active material AAM and the solid electrolyte SE.

[0091] Conductive materials may include carbon-based materials. Conductive materials may include one or more selected from, for example, graphite, carbon black, acetylene black, carbon nanofibers, and carbon nanotubes. However, since the negative electrode active material AAM according to embodiments of this disclosure comprises a porous carrier PM having excellent electrical conductivity, it may not separately include conductive materials (e.g., the negative electrode may be free of or substantially free of graphite, carbon black, acetylene black, carbon nanofibers, and / or carbon nanotubes, where "substantially free of" means that the described components, if present, are only as incidental impurities).

[0092] The negative electrode active material layer 220 may further include a binder. The binder may include a material that causes the negative electrode active material AAM, the solid electrolyte SE, and the conductive material contained in the negative electrode active material layer 220 to adhere to each other and improves the adhesion between the negative electrode active material layer 220 and the negative electrode current collector 210. The binder may include at least one selected from, for example, polyvinylidene fluoride, styrene-butadiene rubber (SBR), polytetrafluoroethylene, vinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, and polymethyl methacrylate.

[0093] Based on a total of 100 parts by weight of the negative electrode active material AAM, solid electrolyte SE, conductive material, and binder, the negative electrode active material AAM may be included in the negative electrode active material layer 220 in an amount of about 60 parts by weight to about 99 parts by weight. Based on a total of 100 parts by weight of the negative electrode active material AAM, solid electrolyte SE, conductive material, and binder, the solid electrolyte SE may be included in the negative electrode active material layer 220 in an amount of about 0.1 parts by weight to about 40 parts by weight. If (for example, when) the amount of each of the negative electrode active material AAM and the solid electrolyte SE falls within the above range, the negative electrode for the all-solid-state battery can have excellent capacity characteristics and superior conductivity (e.g., electrical conductivity).

[0094] A method for manufacturing a negative electrode for an all-solid-state battery according to embodiments of the present disclosure will now be described in more detail.

[0095] A method for manufacturing a negative electrode for an all-solid-state battery according to embodiments of the present disclosure may include the following steps: preparing a negative electrode active material; mixing the negative electrode active material and a solid electrolyte to prepare a negative electrode active material slurry; and coating the negative electrode active material slurry onto a negative electrode current collector. The step of preparing the negative electrode active material may include preparing a porous support and performing a vapor deposition process on the porous support to form silicon nanoparticles.

[0096] The steps for preparing a porous support may include forming porous hard carbon. There are no particular limitations on the method for forming porous hard carbon, and any suitable method used in the art may be used. The steps for forming porous hard carbon may include, for example, heat treating a carbon source, activating the heat-treated carbon source, and performing a pulverization process.

[0097] Carbon sources may include coal pitch, petroleum pitch, petroleum coke, coal coke, polyvinyl chloride, mesophase pitch, tar, low molecular weight heavy oil, polyvinyl alcohol resin, furfuryl alcohol resin, trinitrotoluene, citric acid, stearic acid, polyvinylidene fluoride, carboxymethyl cellulose, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, polyethylene, polypropylene, ethylene-propylene-diene monomer (EPDM), polyacrylic acid, sodium polyacrylate, polyacrylonitrile, gelatin, sugars (e.g., glucose and sucrose), phenolic resins, naphthalene resins, polyamide resins, furan resins, polyimide resins, cellulose resins, styrene resins, epoxy resins, vinyl chloride resins, or combinations thereof.

[0098] In embodiments, heat treatment can be performed in an atmosphere of an oxidizing gas, an inert gas, or a mixture thereof. The oxidizing gas may include oxygen, ozone, or a combination thereof; the inert gas may include nitrogen, helium, neon, argon, or a combination thereof; and the mixed gas may include air, but this disclosure is not limited thereto. For example, heat treatment can be performed for about 1 hour to about 10 hours at a temperature of about 100°C to 1,000°C.

[0099] In the embodiments, carbon activation can be carried out in an oxidizing gas atmosphere. The oxidizing gas atmosphere can be a water vapor atmosphere, but this disclosure is not particularly limited thereto. The activation temperature can be in the range of about 500°C to about 1,000°C, and activation can be carried out for about 0.5 hours to about 10 hours at a pressure of about 0.1 bar to 10 bar.

[0100] The pulverization process can be performed before or after the activation process. There are no particular limitations on the pulverization process, and for example, a ball mill can be used. The size of the porous carrier can be adjusted to a suitable or desired size through the pulverization process.

[0101] Silicon nanoparticles can be formed by vapor deposition on a prepared porous support. Vapor deposition processes can include chemical vapor deposition (CVD). The raw materials for silicon nanoparticles can include SiH4 gas, Si2H6 gas, Si3H8 gas, SiCl4 gas, or combinations thereof.

[0102] Vapor deposition processes can be performed at temperatures where silicon becomes amorphous silicon (a-Si), for example, in the range of about 400°C to about 700°C. If (for example, when) the vapor deposition process temperature is greater than about 700°C, the deposited silicon may become crystalline, thereby exacerbating the increase in volume expansion during charging and discharging and degrading cycle life characteristics, which is undesirable. If (for example, when) the vapor deposition process temperature is below about 400°C, the silicon feedstock may not decompose effectively and may act as an impurity remaining on the porous carrier, which is undesirable.

[0103] In the vapor deposition process, the flow rate of the gas used as the silicon feedstock can be in the range of approximately 0.3 L / min to approximately 1 L / min or approximately 0.3 L / min to approximately 0.6 L / min. Through the above process, the pores of the porous carrier can be filled with silicon.

[0104] The deposition time can range from about 0.5 hours to about 5 hours or from about 0.5 hours to about 3 hours. The vapor deposition time and flow rate can be adjusted according to the porosity of the porous carrier to deposit a suitable or desired amount of silicon nanoparticles.

[0105] Embodiments of this disclosure will now be discussed in more detail through examples. However, these embodiments are provided to illustrate examples of this disclosure, and the scope of this disclosure is not limited to these embodiments.

[0106] Example Manufacturing of negative electrode (1) Preparation of negative electrode active material A porous carbon support (commercially available from IOPsilion) is subjected to a chemical vapor deposition process at 400°C using SiH4 gas at a flow rate of 0.5 L / min to fill the pores of the porous carbon support with silicon. During this stage, the amount of SiH4 gas is controlled such that the weight ratio of porous carbon support to silicon is 55:45.

[0107] The negative electrode active material or porous carbon support including deposited silicon has an average particle size of approximately 10 μm (D 50 ).

[0108] (2) Fabrication of the negative electrode layer A negative electrode active material, a sulfide-based solid electrolyte (Li6PS5Cl), an acrylate polymer binder (specifically, polymethyl methacrylate), and single-walled carbon nanotubes were mixed in a weight ratio of 85:11.5:3:0.5 to prepare a negative electrode active material slurry. The prepared slurry was coated onto a stainless steel foil, then dried and pressed to fabricate the negative electrode layer.

[0109] Manufacturing of all-solid-state batteries (1) Fabrication of the positive electrode layer Preparing LiNi 0.9 Co 0.05 Mn 0.05O2 (NCM) powder was used as the positive electrode active material. A crystalline silver sulfide germanite-type solid electrolyte (Li6PS5Cl) was prepared as the solid electrolyte. A butyl acrylate binder and a single-walled carbon nanotube conductive material were prepared. The positive electrode active material, solid electrolyte, conductive material, and binder were mixed in a weight ratio of 85.0:13.44:0.56:1.0 to prepare a positive electrode active material layer composition. The positive electrode active material layer composition was coated onto an aluminum current collector and dried to fabricate a positive electrode layer comprising a positive electrode active material layer with a thickness of approximately 200 μm.

[0110] (2) Manufacturing of solid electrolyte layer A solid electrolyte Li6PS5Cl of sulfosilgermanium ore type was added to an isobutyl isobutyrate binder solution containing an acrylate polymer (specifically, polymethyl methacrylate) to prepare a solid electrolyte solution (solid content: 50 wt%, mixing ratio of solid electrolyte to binder: 98.7:1.3 by weight).

[0111] A solid electrolyte solution was coated onto a release polytetrafluoroethylene film and dried at 60°C for 2 hours to produce a solid electrolyte layer with a thickness of 100 μm.

[0112] (3) Manufacturing of all-solid-state batteries The negative electrode layer, solid electrolyte layer, and positive electrode layer are stacked sequentially. The stack is sealed in a bag and subjected to a high temperature of 80°C for 30 minutes at 500 MPa using a warm isostatic press (WIP) to fabricate an all-solid-state battery.

[0113] Comparative Example 1 Preparation of negative electrode active material Except that a mixture of silicon particles and carbon is used instead of the porous carbon support in which silicon nanoparticles are formed, the negative electrode layer is manufactured according to a method substantially the same as that in the examples, except that the negative electrode active material is a mixture of silicon and carbon. The negative electrode active material in the form of a mixture of silicon and carbon is prepared as follows.

[0114] Micron-sized silicon particles (average particle size 1 μm to 5 μm) were ball-milled to prepare silicon precursors with sizes ranging from 85 nm to 100 nm. The silicon precursors, stearic acid, and ethanol were mixed in a weight ratio of 9:1:110 to prepare a dispersion. The dispersion was then spray-dried at 120 °C using a spray dryer.

[0115] The spray-dried product and mesophase carbon pitch were mixed at a weight ratio of 55:20, and the mixture was heat-treated in a N2 atmosphere at a temperature of 800°C to 1,000°C to form an amorphous carbon-silicon composite.

[0116] Fabrication of the negative electrode layer A negative electrode active material, a sulfide-based solid electrolyte (Li6PS5Cl), an acrylate polymer binder (specifically, polymethyl methacrylate), and single-walled carbon nanotubes were mixed in a weight ratio of 85:11.5:3:0.5 to prepare a negative electrode active material slurry. The prepared slurry was coated onto a stainless steel foil, then dried and pressed to fabricate the negative electrode layer.

[0117] Manufacturing of all-solid-state batteries All-solid-state batteries are manufactured using a method substantially the same as that described in the examples.

[0118] Comparative Example 2 Preparation of negative electrode active material The negative electrode active material is prepared using a method substantially the same as that described in the examples.

[0119] Manufacturing the negative electrode layer A negative electrode active material, polyvinyl alcohol binder, and single-walled carbon nanotubes were mixed in a weight ratio of 90:9:1 to prepare a negative electrode active material slurry. The prepared slurry was coated onto a stainless steel foil, then dried and pressed to fabricate the negative electrode layer.

[0120] Manufacturing of all-solid-state batteries All-solid-state batteries are manufactured using a method substantially the same as that described in the examples.

[0121] Evaluation 1: X-ray diffraction analysis of the active material of the negative electrode X-ray diffraction (XRD) analysis was performed on the porous carbon support fabricated in the examples and the porous carbon support in which silicon was vapor-deposited. The results are shown in... Figure 7 (See also) Figure 7 It can be observed that in the 2θ-based XRD spectrum of the porous carbon support in which no silicon is deposited, the carbon (002) peak centered at 24° appears in the range of 20° to 27°. Still referring to... Figure 7 It can be observed that in the 2θ-based XRD spectrum of the porous carbon support after silicon deposition, a silicon (101) peak centered at 28° appears in the range of 15° to 35°. Therefore, it can be determined that silicon is deposited and present within the porous carbon support.

[0122] Evaluation 2: Porosity of the negative electrode active material Pore ​​size and specific surface area can be measured using the Barrett-Joyner-Halenda (BJH) method and / or calculated using nonlinear density functional theory (NLDFT) methods via N2 adsorption / desorption isotherms. For example, the porous support can be subjected to a pretreatment process in which it is heated to 523 K at a rate of 10 K / min, then held at that temperature for 2 to 10 hours at a pressure of 100 mmHg or lower, and in liquid nitrogen at a relative pressure (P / P0) controlled to be below 0.01 Torr up to 10 g / cm³. 3 STP is adsorbed at a single point and then re-adsorbed at 32 points up to 0.955 Torr. Nitrogen desorption can then be performed at 24 points up to a relative pressure of 0.14 Torr to measure pore size and specific surface area.

[0123] Micropore diameter and specific surface area can be adjusted from relative pressure (P / P0) below 0.01 Torr up to 10 g / cm³. 3 The adsorption of nitrogen at a single point in the STP can be measured within the range where excess nitrogen (N2) can be adsorbed starting from a relative pressure of 0.01 Torr or higher, and the specific surface area can be calculated from the amount of N2 measured using this method relative to the volume of the porous carrier.

[0124] The specific surface area of ​​the porous carbon support measured in the example was 1,450 m². 2 / g, and the nitrogen adsorption / desorption isotherms and pore distribution of the porous carbon support in the examples are shown in Figure 8 and Figure 9 middle.

[0125] Reference Figure 8 It can be observed that, due to the numerous pores in the porous carbon support, a large amount of nitrogen is adsorbed. (Refer to...) Figure 9 It can be observed that the porous carbon support contains a high concentration of nanopores with a pore size of 2 nm or smaller.

[0126] Evaluation 3: Cross-section of the electrode plate Figure 10 These are SEM images and EDX mapping images of the negative electrode fabricated in this embodiment. (Refer to...) Figure 10 It can be observed that silicon, as the negative electrode active material, is uniformly distributed within the porous carbon support, and sulfur-containing solid electrolyte is uniformly present on the surface of the negative electrode active material.

[0127] Evaluation 4: Rate charging characteristics of all-solid-state batteries For the all-solid-state batteries manufactured in the examples and comparative examples, cycling was performed by charging at 25°C with a constant current to an upper limit voltage of 4.25V, and then discharging with a constant current of 0.33C to a cutoff voltage of 2.5V. The charging current was changed to 0.33C, 0.5C, 1C, and 2C, and the charge capacity for each case was evaluated and listed in Table 1.

[0128] Table 1

[0129] Referring to Table 1, it can be observed that, compared with Comparative Example 1 and Comparative Example 2, the embodiment has a high charge capacity at all C rates.

[0130] Evaluation 5: Rate discharge characteristics of all-solid-state batteries For the rechargeable lithium batteries manufactured in the Examples and Comparative Examples 1 and 2, cycling was performed by charging at a constant current of 0.33C to an upper limit voltage of 4.25V at 25°C, and then discharging at a constant current to a cutoff voltage of 2.5V. The discharge current was changed to 0.33C, 0.5C, 1C, and 2C, and the discharge specific capacity for each case is evaluated and listed in Table 2.

[0131] Table 2

[0132] Referring to Table 2, it can be observed that, compared with Comparative Example 1 and Comparative Example 2, the Example exhibits superior discharge capacity at all C rates.

[0133] Evaluation 6: Thickness deviation of all-solid-state batteries After 25 discharge and charge cycles, the thickness of the all-solid-state batteries manufactured according to the examples and Comparative Examples 1 and 2 was measured after charging and discharging, and the results are listed in Table 3. The battery thickness was measured using a commercially available fixture (model: EQ-PTC-TEM) from MTI Corporation.

[0134] Table 3

[0135] Referring to Table 3, it can be observed that the thickness variation of the all-solid-state battery according to the embodiment is less than that of the all-solid-state batteries according to Comparative Example 1 and Comparative Example 2.

[0136] The negative electrode for an all-solid-state battery according to embodiments of the present disclosure may include a porous carrier and silicon filling at least a portion of the pores of the porous carrier, thereby achieving excellent capacity, lithium-ion mobility and conductivity.

[0137] If (for example, when) a method for manufacturing a negative electrode for an all-solid-state battery according to an embodiment of the present disclosure is used, it may be possible to manufacture a negative electrode with high lithium-ion mobility and conductivity.

[0138] While the subject matter of this disclosure has been described in conjunction with what is now considered to be exemplary embodiments, it will be understood that this disclosure is not limited to the disclosed embodiments and is intended to cover various suitable modifications and equivalent arrangements included within the spirit and scope of the appended claims and their equivalents. Therefore, the foregoing embodiments should be understood as exemplary and not as limiting this disclosure in any way.

Claims

1. A negative electrode for an all-solid-state battery, the negative electrode comprising: Negative electrode current collector; as well as Negative electrode active material layer, The negative electrode active material layer comprises a negative electrode active material and a solid electrolyte. The negative electrode active material comprises a porous carrier and silicon, and The silicon fills at least a portion of the pores in the porous carrier.

2. The negative electrode according to claim 1, wherein, The porous support comprises amorphous hard carbon, and The amorphous hard carbon exhibits peaks at 20° to 26° in a 2θ-based XRD spectrum.

3. The negative electrode according to claim 1, wherein, The average particle size D of the porous carrier 50 Within the range of 1μm to 50μm.

4. The negative electrode according to claim 1, wherein, The pores of the porous carrier include micropores, and The volume occupied by the micropores is 50% to 98% of the total volume of the pores.

5. The negative electrode according to claim 1, wherein, The specific surface area of ​​the porous carrier is 1m². 2 / g to 2,000m 2 Within the range of / g.

6. The negative electrode according to claim 1, wherein, The silicon is present in an amount of 20 to 80 parts by weight relative to 100 parts by weight of the negative electrode active material.

7. The negative electrode according to claim 1, wherein, The silicon is formed on the porous carrier by vapor deposition.

8. The negative electrode according to claim 1, wherein, The negative electrode active material is present in an amount of 60 to 99 parts by weight relative to 100 parts by weight of the negative electrode active material layer.

9. The negative electrode according to claim 1, wherein, The negative electrode active material layer also includes a binder.

10. The negative electrode according to claim 1, wherein: The solid electrolyte includes sulfide solid electrolytes, and The average particle size of the negative electrode active material is greater than the average particle size of the solid electrolyte.

11. An all-solid-state battery, the all-solid-state battery comprising: The negative electrode according to any one of claims 1 to 10; Positive electrode; as well as A solid electrolyte layer is located between the negative electrode and the positive electrode.

12. The all-solid-state battery according to claim 11, wherein: The all-solid-state battery has a first height in the discharged state. The all-solid-state battery has a second height in the charging state, and The ratio of the second height to the first height is in the range of 1.1 to 1.

5.

13. The all-solid-state battery according to claim 11, wherein, The positive electrode comprises a positive electrode active material and a solid electrolyte.

14. The all-solid-state battery according to claim 11, wherein, The solid electrolyte layer includes a sulfide-based solid electrolyte.

15. A method for manufacturing a negative electrode for an all-solid-state battery, the method comprising the steps of: Preparation of negative electrode active material; The negative electrode active material and the solid electrolyte are mixed to prepare a negative electrode active material slurry; as well as The negative electrode active material slurry is coated onto the negative electrode current collector. The step of preparing the negative electrode active material includes: preparing a porous support; and subjecting the porous support to a vapor deposition process to form silicon nanoparticles.

16. The method according to claim 15, wherein, The vapor deposition process is carried out at a temperature of 400°C to 700°C.

17. The method according to claim 15, wherein, The porous carrier includes amorphous hard carbon. The amorphous hard carbon exhibits peaks at 20° to 26° in a 2θ-based XRD spectrum.

18. The method according to claim 15, wherein, The average particle size D of the porous carrier 50 Within the range of 1μm to 50μm.

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