All-solid-state batteries

Abstract

This invention relates to an all-solid-state battery, which comprises a positive electrode including a positive electrode active material layer containing a positive electrode active material, a negative electrode including a negative electrode catalyst and a negative electrode catalyst layer containing Nb2O5, and an electrolyte layer, wherein the Nb2O5 content is 1% to 30% by weight relative to 100% by weight of the entire negative electrode catalyst layer, and the ratio of the capacity of the negative electrode catalyst layer to the capacity of the positive electrode (N / P) is 0.1 or more and less than 0.5.

Description

[Technical Field]

[0001] This concerns all-solid-state batteries. [Background technology]

[0002] Recently, with the rapid proliferation of electronic devices that use batteries, such as mobile phones, laptops, and electric vehicles, the demand for rechargeable batteries that are small, lightweight, and yet relatively high-capacity has been rapidly increasing. In particular, lithium-ion batteries are attracting attention as a power source for portable devices due to their light weight and high energy density. As a result, research and development to improve the performance of lithium-ion batteries is being actively pursued.

[0003] Among lithium-ion secondary batteries, all-solid-state batteries are batteries in which all materials are solid, and in particular, batteries that use a solid electrolyte. This solid electrolyte is located between the positive and negative electrodes, preventing direct contact between the two electrodes while simultaneously serving as a passage for lithium ions to move during the charging and discharging process. [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] In one embodiment, an all-solid-state battery exhibiting excellent electrochemical performance is provided. [Means for solving the problem]

[0005] In one embodiment, an all-solid-state battery is provided comprising: a positive electrode including a positive electrode active material layer containing a positive electrode active material; a negative electrode including a negative electrode catalyst layer containing a negative electrode catalyst and Nb2O5; and an electrolyte layer, wherein the Nb2O5 content is 1% to 30% by weight relative to 100% by weight of the entire negative electrode catalyst layer, and the ratio of the capacity of the negative electrode catalyst layer to the capacity of the positive electrode (N / P) is 0.1 or more and less than 0.5.

[0006] The Nb2O5 content may be 3% to 30% by weight or 5% to 15% by weight relative to 100% by weight of the entire negative electrode catalyst layer.

[0007] The ratio (N / P) of the capacity of the negative electrode catalyst layer to the capacity of the positive electrode may be 0.1 to 0.4, or 0.1 to 0.3.

[0008] The anode catalyst may be a carbon-based material, metal particles, or a combination thereof.

[0009] The carbon-based material may be amorphous carbon.

[0010] The metal particles may be any one selected from Ag, Zn, Al, Sn, Mg, Ge, Cu, In, Ni, Bi, Au, Si, Pt, Pd, and any combination thereof.

[0011] The electrolyte layer may be a solid electrolyte. The solid electrolyte may be a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a halide-based solid electrolyte, or a solid polymer electrolyte.

[0012] The negative electrode further includes a current collector supporting the negative electrode catalyst layer, and may further include a lithium deposition layer formed between the current collector and the negative electrode catalyst layer during initial charging.

[0013] The positive electrode active material may be a positive electrode active material or a sulfur-based compound capable of reversibly intercepting and releasing lithium ions. In one embodiment, the positive electrode active material may be a positive electrode active material capable of reversibly intercepting and releasing lithium ions. [Effects of the Invention]

[0014] An all-solid-state battery according to one embodiment can exhibit improved ionic conductivity and high efficiency characteristics. [Brief explanation of the drawing]

[0015] [Figure 1] This is a schematic diagram illustrating an all-solid-state battery according to one embodiment. [Figure 2]This is a schematic cross-sectional view showing the state of an all-solid-state battery according to one embodiment after charging. [Figure 3] This is a surface SEM image of the negative electrode manufactured according to Example 1. [Figure 4] This graph shows the EDAX measurement results for the negative electrode manufactured according to Example 1. [Figure 5] This is a 20,000x magnified image of the SEM photograph shown in Figure 3. [Figure 6] Figure 5 is a graph showing the EDAX measurement results for selected area 1 and selected area 2. [Modes for carrying out the invention]

[0016] Embodiments of the present invention will be described in detail below. However, these are presented as examples only and are not limited thereto; the present invention is defined solely by the scope of the claims described below.

[0017] Unless otherwise specified herein, when a part such as a layer, film, region, or plate is said to be “on top of” another part, this includes not only the case where it is “directly on top of” another part, but also the case where there is yet another part in between.

[0018] In this invention, "particle size" or "particle diameter" can refer to the average particle diameter. Furthermore, the average particle diameter can be defined as the average particle diameter (D50) at 50% of the cumulative volume on a cumulative size-distribution curve. Particle diameter can be measured, for example, by electron microscopy using a scanning electron microscope (SEM), a field emission scanning electron microscope (FE-SEM), or by laser diffraction. More specifically, when measuring by laser diffraction, the particles to be measured are dispersed in a dispersion medium, then introduced into a commercially available laser diffraction particle size analyzer (e.g., Microtrac's MT 3000), and after irradiating with ultrasound at approximately 28 kHz at an output of 60 W, the average particle diameter (D50) at 50% of the particle diameter distribution on the analyzer can be calculated.

[0019] An all-solid-state battery according to one embodiment includes a positive electrode, a negative electrode, and an electrolyte, wherein the negative electrode includes a negative electrode catalyst and a negative electrode catalyst layer containing Nb2O5, and the ratio of the capacity of the negative electrode catalyst layer to the capacity of the positive electrode (N / P) is 0.1 or more and less than 0.5.

[0020] In one embodiment, the negative electrode containing the negative electrode catalyst layer is a deposition-type negative electrode. Such a deposition-type negative electrode does not contain negative electrode active material during battery assembly, but during battery charging, lithium metal or the like is deposited, and this acts as the negative electrode active material. To explain this in more detail, during charging of an all-solid-state battery, lithium ions are released from the positive electrode active material, pass through the solid electrolyte, and move to the negative electrode side. They are deposited on the negative electrode current collector, resulting in the formation of a lithium deposition layer between the current collector and the negative electrode layer. A negative electrode having such a lithium deposition layer is called a deposition-type negative electrode.

[0021] In one embodiment, the negative electrode contains Nb2O5 in the negative electrode catalyst layer. Nb2O5 is a lithium-affinity material, and during charging, Lix It is converted to Nb2O5, which can act as a pseudocapacitor, performing lithium storage and dispersion roles. Therefore, the ion conductivity characteristics of the negative electrode can be improved.

[0022] In particular, such effects can be obtained when Nb2O5 is used in the negative electrode of a battery where the ratio of the capacity of the negative electrode catalyst layer to the capacity of the positive electrode (N / P, hereinafter referred to as the "N / P ratio") is 0.1 or more and less than 0.5, and when it is used in a content of 1% to 30% by weight relative to 100% by weight of the entire negative electrode catalyst layer.

[0023] In one embodiment, the N / P ratio does not refer to the ratio of the negative electrode capacity to the positive electrode capacity as defined in a typical lithium-ion secondary battery, but rather to the ratio of the negative electrode catalyst layer capacity to the positive electrode capacity. In this case, capacity refers to charging capacity. Furthermore, the capacity of the negative electrode catalyst layer can be measured by lithium ions when lithium ions move to the negative electrode side during charging and become present within the negative electrode catalyst layer.

[0024] In one embodiment, the capacity of the negative electrode catalyst layer can be obtained by charging a half-cell containing the negative electrode and lithium counter electrode once at 0.01C to 0.1C and measuring the capacity up to the inflection point near 0mV (vs.Li). The capacity of the positive electrode can be determined from the theoretical capacity of the positive electrode active material.

[0025] Even if the negative electrode catalyst layer contains Nb2O5, if the amount is less than 1% by weight, it is not suitable because the amount is excessively small to obtain the desired effect from using Nb2O5. Furthermore, if the amount exceeds 30% by weight, it is also unsuitable because Nb2O5 has a large irreversible capacity and low electrical conductivity, leading to significant problems.

[0026] Furthermore, even if the Nb2O5 content falls within this range, using it in a battery that deviates from the conditions of an N / P ratio of 0.1 or higher and less than 0.5 will not yield the desired effect and is therefore inappropriate. When used in a battery with an N / P ratio of less than 0.1, the negative electrode catalyst layer may not perform its role sufficiently, leading to uneven lithium growth, which is also inappropriate. Additionally, when used in a battery with an N / P ratio of 0.5 or higher, the negative electrode catalyst layer may accept an excessive amount of lithium, potentially causing irreversible damage due to dead lithium that does not participate in the charge-discharge reaction. Moreover, an increase in the battery's N / P ratio will also increase the thickness of the negative electrode. In one embodiment of the all-solid-state battery, the negative electrode does not contain a solid electrolyte, resulting in low lithium ion conductivity. Therefore, if the thickness of the negative electrode increases, charging and discharging will not be sufficient, and the desired effect cannot be obtained.

[0027] Furthermore, an N / P ratio of less than 1 generally indicates that lithium ions that have moved to the negative electrode side during charging are LiC x(x=1-6) The reaction takes place (0V during initial charging [vs.Li / Li + Up to a certain capacity, the remaining ions do not participate in this reaction and are deposited between the negative electrode catalyst layer and the current collector, forming a deposition-type negative electrode. In one embodiment, the maximum value is less than 0.5, so it can be considered a battery in which a larger amount of lithium is deposited on the negative electrode surface than in a typical deposition-type negative electrode.

[0028] In one embodiment, the Nb2O5 content may be 1% to 30% by weight, 3% to 30% by weight, 3% to 20% by weight, 5% to 15% by weight, or 5% to 10% by weight, based on 100% by weight of the entire negative electrode catalyst layer.

[0029] In one embodiment, the N / P ratio may be 0.1 or greater and less than 0.5, or 0.1 to 0.4, or 0.1 to 0.3 or 0.1 to 0.2.

[0030] The negative electrode catalyst layer may include a carbon-based material, metal particles, or a combination thereof as the negative electrode catalyst. Furthermore, during charging of the all-solid-state battery, lithium ions are released from the positive electrode active material and deposited onto the negative electrode current collector, resulting in a lithium deposition layer being further included between the current collector and the negative electrode catalyst layer. Carbon-based materials have sp² (sp²) which are advantageous for deposition. 3 Carbon-based materials with a high carbon content may also be used. Examples include carbon black, acetylene black, denka black, ketjen black, furnace black, activated carbon, graphene, or combinations thereof. An example of carbon black is Super P (Timcal). Amorphous carbon is not the only option; any material classified as amorphous carbon in this field is acceptable.

[0031] Amorphous carbon may be a single particle, or it may have a secondary particle form in which multiple primary particles are aggregated, or it may be a combination of these.

[0032] The particle size of a single particle may be between 10 nm and 60 μm. Furthermore, the particle size of primary particles may be between 20 nm and 100 nm, and the particle size of secondary particles may be between 1 μm and 20 μm.

[0033] In one embodiment, the particle size of the primary particles may be 20 nm or more, 30 nm or more, 40 nm or more, 50 nm or more, 60 nm or more, 70 nm or more, 80 nm or more, or 90 nm or more, and may also be 100 nm or less, 90 nm or less, 80 nm or less, 70 nm or less, 60 nm or less, 50 nm or less, 40 nm or less, or 30 nm or less.

[0034] In one embodiment, the particle size of the secondary particles may be 1 μm or more, 3 μm or more, 5 μm or more, 7 μm or more, 10 μm or more, or 15 μm or more, and may be 20 μm or less, 15 μm or less, 10 μm or less, 7 μm or less, 5 μm or less, or 3 μm or less.

[0035] The morphology of the primary particles may be spherical, elliptical, plate-like, or a combination thereof. In one embodiment, the morphology of the primary particles may be spherical, elliptical, or a combination thereof.

[0036] The metal particles may be any one selected from Ag, Zn, Al, Sn, Mg, Ge, Cu, In, Ni, Bi, Au, Si, Pt, Pd, and combinations thereof, and in one embodiment, they may be Ag. When the negative electrode catalyst layer contains metal particles, the electrical conductivity of the negative electrode can be improved.

[0037] The metal particles can have a size of 5 nm to 800 nm. The size of the metal particles may be 5 nm or more, 50 nm or more, 100 nm or more, 150 nm or more, 200 nm or more, 250 nm or more, 300 nm or more, 350 nm or more, 400 nm or more, 450 nm or more, 500 nm or more, 550 nm or more, 600 nm or more, 650 nm or more, 700 nm or more, or 750 nm or more. Alternatively, the size of the metal particles may be 800 nm or less, 750 nm or less, 700 nm or less, 650 nm or less, 600 nm or less, 550 nm or less, 500 nm or less, 450 nm or less, 400 nm or less, 350 nm or less, 300 nm or less, 250 nm or less, 200 nm or less, 150 nm or less, 100 nm or less, or 50 nm or less. When the size of the metal particles is within the aforementioned range, the battery characteristics (e.g., lifespan characteristics) of the all-solid-state battery can be improved.

[0038] If the negative electrode catalyst layer contains both carbon-based material and metal particles, the mixing ratio of carbon-based material to metal particles may be a weight ratio of 1:1 to 99:1. For example, the weight of the carbon-based material may be 1 or more, 2 or more, 3 or more, 4 or more, 5 or more, 10 or more, 15 or more, 20 or more, 25 or more, 30 or more, 35 or more, 40 or more, 45 or more, 50 or more, 55 or more, 60 or more, 65 or more, 70 or more, 75 or more, 80 or more, 85 or more, 90 or more, or 95 or more relative to the metal particles, and may be 99 or less, 95 or less, 90 or less, 85 or less, 80 or less, 75 or less, 70 or less, 65 or less, 60 or less, 55 or less, 50 or less, 45 or less, 40 or less, 35 or less, 30 or less, 25 or less, 20 or less, 15 or less, 10 or less, 5 or less, 4 or less, 3 or less, or 2 or less. For example, the weight ratio of carbon-based material to metal particles may be 1:1 to 5:1, 1:1 to 10:1, 1:1 to 20:1, 1:1 to 25:1, 1:1 to 30:1, 1:1 to 40:1, 1:1 to 50:1, 1:1 to 60:1, 1:1 to 70:1, 1:1 to 80:1, or 1:1 to 90:1. When carbon-based material and metal particles are included in the aforementioned weight ratios, the electrical conductivity of the negative electrode can be further improved.

[0039] Carbon-based materials, metal particles, or combinations thereof may be present in an amount of 50% to 98% by weight, or 60% to 90% by weight, relative to the total weight of the negative electrode catalyst layer.

[0040] Furthermore, the negative electrode catalyst layer may contain a binder and may further contain a conductive material.

[0041] The binder may be, for example, styrene-butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, vinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, polymethyl methacrylate, carboxymethylcellulose, hydroxypropylcellulose, diacetylcellulose, or a combination thereof. Carboxymethylcellulose or hydroxypropylcellulose, or diacetylcellulose may be alkali metal salts thereof, and the alkali metal may be Na or Li. The binder is not limited to these, and any binder used in the art is acceptable.

[0042] The binder content may be 0.1% to 30% by weight, or 0.1% to 10% by weight, relative to the total weight of each component of the negative electrode for the all-solid-state battery, or relative to the total weight of the negative electrode catalyst layer. Within this content range, the binder can exhibit sufficient adhesive ability without degrading battery performance.

[0043] Conductive materials are used to impart conductivity to electrodes, and any material that does not undergo chemical changes and possesses electronic conductivity can be used. Conductive materials may include, for example, carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjenblack, carbon fibers, carbon nanofibers, and carbon nanotubes; metallic materials in the form of metal powders or metal fibers containing copper, nickel, aluminum, silver, etc.; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0044] The conductive material may be included in an amount of 0.1% to 15% by weight, or 0.1% to 10% by weight, relative to the total weight of each component of the negative electrode for the all-solid-state battery, or relative to the total weight of the negative electrode catalyst layer. Within this content range, the conductive material can improve electrical conductivity without degrading battery performance.

[0045] The negative electrode further includes a current collector that supports the negative electrode catalyst layer. The current collector may be, 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), or an alloy thereof, and may be in the form of a foil or a sheet.

[0046] The negative electrode catalyst layer may further include additives such as a filler, a dispersant, and an ion conductive material. In addition, known materials generally used in all-solid-state batteries, such as fillers, dispersants, and ion conductive materials that can be included in the negative electrode catalyst layer, can be used.

[0047] The positive electrode can include a positive electrode active material layer containing a positive electrode active material and a current collector that supports this positive electrode active material layer.

[0048] The positive electrode active material may be a positive electrode active material capable of reversibly occluding and releasing lithium ions. For example, the positive electrode active material can be one or more of composite oxides of metals selected from cobalt, manganese, nickel, and combinations thereof with lithium. Specific examples of the positive electrode active material include Li a A 1-b B 1 b D 1 2(0.90 ≦ a ≦ 1.8, 0 ≦ b ≦ 0.5); Li a E 1-b B 1 b O 2-c D 1 c (0.90 ≦ a ≦ 1.8, 0 ≦ b ≦ 0.5, 0 ≦ c ≦ 0.5); Li a E 2-b B 1 b O 4-c D 1 c (0.90 ≦ a ≦ 1.8, 0 ≦ b ≦ 0.5, 0 ≦ c ≦ 0.5); Li a Ni 1-b-c Co b B 1c D 1 α (0.90≦a≦1.8、0≦b≦0.5、0≦c≦0.5、0<α≦2);Li a Ni 1-b-c Co b B 1 c O 2-α F 1 α (0.90≦a≦1.8、0≦b≦0.5、0≦c≦0.5、0<α<2);Li a Ni 1-b-c Co b B 1 c O 2-α F 1 2(0.90≦a≦1.8、0≦b≦0.5、0≦c≦0.5、0<α<2);Li a Ni 1-b-c Mr b B 1 c D 1 α (0.90≦a≦1.8、0≦b≦0.5、0≦c≦0.5、0<α≦2);Li a Ni 1-b-c Mr b B 1 c O 2-α F 1 α (0.90≦a≦1.8、0≦b≦0.5、0≦c≦0.5、0<α<2);Li a Ni 1-b-c Mr b B 1 c O 2-α F 1 2(0.90≦a≦1.8、0≦b≦0.5、0≦c≦0.5、0<α<2);Li a Ni b HAVE BEEN c G d O2(0.90≦a≦1.8、0≦b≦0.9、0≦c≦0.5、0.001≦d≦0.1);Li a Ni b Co c Mr d G eO2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0 ≤ d ≤ 0.5, 0.001 ≤ e ≤ 0.1); Li a NiG b O2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1); Li a CoG b O2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1); Li a MnG b O2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1); Li a Mn2G b O4(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1); QO2; QS2; LiQS2; V2O5; LiV2O5; LiI 1 O2; LiNiVO4; Li (3-f) J2(PO4)3(0 ≤ f ≤ 2); Li (3-f) Fe2(PO4)3(0 ≤ f ≤ 2); or LiFePO4 may be mentioned.

[0049] In the above chemical formula, A is Ni, Co, Mn, or a combination thereof; B 1 is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements or a combination thereof; D 1 is O, F, S, P, or a combination thereof; E is Co, Mn, or a combination thereof; F 1 is F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; Q is Ti, Mo, Mn, or a combination thereof; I 1 is Cr, V, Fe, Sc, Y, or a combination thereof; J is V, Cr, Mn, Co, Ni, Cu, or a combination thereof.

[0050] According to one embodiment, as the positive electrode active material, LiNi x Co y Al z O2 (NCA), LiNi x Co y Mn zExamples thereof include ternary lithium transition metal oxides such as O2(NCM) (where 0 < x < 1, 0 < y < 1, 0 < z < 1, and x + y + z = 1).

[0051] Of course, those having a coating layer on the surface of this compound can also be used, or the compound and a compound having a coating layer can be mixed and used. This coating layer can contain at least one coating element compound selected from the group consisting of an oxide of the coating element, a hydroxide of the coating element, an oxyhydroxide of the coating element, an oxycarbonate of the coating element, and a hydroxycarbonate of the coating element. The compounds forming these coating layers may be amorphous or crystalline. As the coating element contained in the coating layer, Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, or a mixture thereof can be used. The coating layer formation process can use any coating method as long as such an element is used for the compound in a method that does not adversely affect the physical properties of the positive electrode active material (for example, spray coating, dipping method, etc.). Since this is well understood by those skilled in the art, a detailed description thereof is omitted.

[0052] In addition, as the coating layer, any known coating layer for the positive electrode active material of all-solid-state batteries can be applied, and examples thereof include Li2O-ZrO2 (LZO).

[0053] Here, examples of the shape of the positive electrode active material include particle shapes such as spherical and ellipsoidal. Also, the average particle size of the positive electrode active material is not particularly limited as long as it is within the range applicable to the positive electrode active materials of existing all-solid-state secondary batteries. Also, the content of the positive electrode active material in the positive electrode active material layer is not particularly limited as long as it is within the range applicable to the positive electrode active material layers of existing all-solid-state secondary batteries.

[0054] In one embodiment, the positive electrode active material may be present in an amount of 55% to 99.7% by weight relative to the total weight of the positive electrode active material layer, for example, 74% to 89.8% by weight. When included within this range, the life characteristics can be improved while maximizing the capacity of the all-solid-state battery.

[0055] The positive electrode active material layer may contain a solid electrolyte. The solid electrolyte may be an inorganic solid electrolyte such as a sulfide-based solid electrolyte or an oxide-based solid electrolyte, or it may be a solid polymer electrolyte.

[0056] Sulfide-based solid electrolytes include, for example, Li2S-P2S5, Li2S-P2S5--LiX (where X is a halogen element, e.g., I or Cl), Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, and Li2S-P2S5-Z. m S n (m and n are integers, and Z is Ge, Zn, or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q Examples include (where p and q are integers, and M is P, Si, Ge, B, Al, Ga, or In).

[0057] Sulfide-based solid electrolytes may, for example, be obtained by mixing Li2S and P2S5 in a molar ratio of 50:50 to 90:10, or 50:50 to 80:20. Within this mixing ratio range, sulfide-based solid electrolytes with excellent ionic conductivity can be produced. Ionic conductivity can be further improved by adding other components such as SiS2, GeS2, and B2S3. Mechanical milling and solution methods can be applied as mixing methods. Mechanical milling is a method in which the starting materials are placed in a reactor with a ball mill or the like and vigorously stirred to atomize and mix the starting materials. When using the solution method, the starting materials are mixed in a solvent to obtain the solid electrolyte as a precipitate. In addition, calcination can be performed after mixing. If additional calcination is performed, the crystals of the solid electrolyte can become even more rigid.

[0058] For example, the solid electrolyte may be an argyrodite-type sulfide-based solid electrolyte. A sulfide-based solid electrolyte is, for example, Li a M b P c S d A e (a, b, c, d, and e are all between 0 and 12, M is Ge, Sn, Si, or a combination thereof, and A is one of F, Cl, Br, or I) which specifically include Li3PS4 and Li7P3S 11 Li6PS5Cl, Li6PS5Br, Li6PS5I, etc., may also be used.

[0059] The sulfide-based solid electrolyte may be amorphous or crystalline, or a mixture of both.

[0060] Oxide-based inorganic solid electrolytes include, for example, Li 1+x Ti 2-x Al(PO4)3(LTAP)(0≦x≦4), Li 1+x+y Al x Ti 2-x Si y P 3-y O 12(0 < x < 2, 0 ≤ y < 3), BaTiO3, Pb(Zr,Ti)O3 (PZT), Pb 1-x La x Zr 1-y Ti y O3 (PLZT) (0 ≤ x < 1, 0 ≤ y < 1), PB(Mg3Nb 2 / 3 )O3 - PbTiO3 (PMN - PT), HfO2, SrTiO3, SnO2, CeO2, Na2O, MgO, NiO, CaO, BaO, ZnO, ZrO2, Y2O3, Al2O3, TiO2, SiO2, lithium phosphate (Li3PO4), lithium titanium phosphate (Li x Ti y (PO4)3, 0 < x < 2, 0 < y < 3), Li 1+x+y (Al, Ga) x (Ti, Ge) 2-x Si y P 3-y O 12 (0 ≤ x ≤ 1, 0 ≤ y ≤ 1), lithium lanthanum titanate (Li x La y TiO3, 0 < x < 2, 0 < y < 3), Li2O, LiAlO2, Li2O - Al2O3 - SiO2 - P2O5 - TiO2 - GeO2 - based ceramics, Garnet - based ceramics Li 3+x La3M2O 12 (M = Te, Nb, or Zr; x is an integer from 1 to 10), or mixtures thereof can be included.

[0061] Solid polymer electrolytes are, for example, polyethylene oxide, poly(diallyldimethylammonium) trifluoromethanesulfonylimide (poly(diallyldimethylammonium) TFSI), Cu3N, Li3N, LiPON, Li3PO4.Li2S.SiS2, Li2S.GeS2.Ga2S3, Li2O.11Al2O3, Na2O.11Al2O3, (Na,Li) 1+x Ti 2-x Al x (PO4)3 (0.1 ≤ x ≤ 0.9), Li 1+x Hf 2-x Al x (PO4)3 (0.1 ≤ x ≤ 0.9), Na3Zr2Si2PO12 , Li3Zr2Si2PO 12 , Na5ZrP3O 12 , Na5TiP3O 12 , Na3Fe2P3O 12 , Na4NbP3O 12 , Na-Silicates, Li 0.3 La 0.5 TiO3, Na5MSi4O 12 (M is a rare earth element such as Nd, Gd, Dy, etc.) Li5ZrP3O 12 , Li5TiP3O 12 , Li3Fe2P3O 12 , Li4NbP3O 12 , Li 1+x (M, Al, Ga) x (Ge 1-y Ti y ) 2-x (PO4)3 (x ≤ 0.8, 0 ≤ y ≤ 1.0, M is Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, or Yb), Li 1+x+y Q x Ti 2-x Si y P 3-y O 12 (0 < x ≤ 0.4, 0 < y ≤ 0.6, Q is Al or Ga), Li6BaLa2Ta2O 12 , Li7La3Zr2O 12 , Li5La3Nb2O 12 , Li5La3M2O 12 (M is Nb, Ta), and Li 7+x A x La 3-x Zr2O 12 It can contain one or more selected from the following: (0 < x < 3, A is Zn).

[0062] The solid electrolyte is in particle form, and the average particle size (D50) may be 5.0 μm or less, for example, it may be 0.1 μm to 5.0 μm, 0.5 μm to 5.0 μm, 0.5 μm to 4.0 μm, 0.5 μm to 3.0 μm, 0.5 μm to 2.0 μm, or 0.5 μm to 1.0 μm.

[0063] The solid electrolyte content may be 0.1% to 35% by weight relative to the weight of the negative electrode catalyst layer, for example, 1% to 35% by weight, 5% to 30% by weight, 8% to 25% by weight, or 10% to 20% by weight.

[0064] The solid electrolyte may be present in an amount of 0.1% to 35% by weight relative to the total weight of the positive electrode active material layer, for example, 1% to 35% by weight, 5% to 30% by weight, 8% to 25% by weight, or 10% to 20% by weight. Furthermore, the positive electrode active material layer may contain 65% to 99% by weight of positive electrode active material and 1% to 35% by weight of solid electrolyte relative to the total weight of positive electrode active material and solid electrolyte, for example, 80% to 90% by weight of positive electrode active material and 10% to 20% by weight of solid electrolyte. When the solid electrolyte is present in such concentrations within the positive electrode, the efficiency and lifespan characteristics of the all-solid-state battery can be improved without reducing capacity.

[0065] Furthermore, the positive electrode active material layer may contain a binder. The binder plays a role in ensuring that the positive electrode active material particles adhere well to each other and that the positive electrode active material adheres well to the current collector.

[0066] Examples of binders include, but are not limited to, polyvinyl alcohol, carboxymethylcellulose, hydroxypropylcellulose, diacetylcellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers containing ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, polyacrylonitrile, epoxy resin, nylon, poly(meth)acrylate, and polymethyl(meth)acrylate.

[0067] In one embodiment, the binder may be one or more selected from polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polytetrafluoroethylene, styrene-butadiene rubber, polyacrylonitrile, and polymethyl (meth)acrylate.

[0068] The binder may be included in an amount of 0.1% to 5% by weight, or 0.1% to 3% by weight, relative to the total weight of each component of the positive electrode for the all-solid-state battery, or relative to the total weight of the positive electrode active material layer. Within this content range, the binder can exhibit sufficient adhesive ability without degrading battery performance.

[0069] The positive electrode active material layer may further contain a conductive material. This conductive material is used to impart conductivity to the electrode, and any electronically conductive material that does not cause chemical changes can be used. The conductive material may include, for example, carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjenblack, carbon fibers, carbon nanofibers, and carbon nanotubes; metallic materials containing copper, nickel, aluminum, silver, etc., in the form of metal powders or metal fibers; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0070] The conductive material may be included in an amount of 0.1% to 5% by weight, or 0.1% to 3% by weight, relative to the total weight of each component of the positive electrode for the all-solid-state battery, or relative to the total weight of the positive electrode active material layer. Within this content range, the conductive material can improve electrical conductivity without degrading battery performance.

[0071] The current collector may 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), or alloys thereof, and may be in the form of foil or sheet.

[0072] The electrolyte layer can include a solid electrolyte. Such a solid electrolyte may be an inorganic solid electrolyte such as a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a halide-based solid electrolyte, or a solid polymer electrolyte.

[0073] The sulfide-based solid electrolyte, the oxide-based solid electrolyte, and the solid polymer electrolyte are as described above.

[0074] The halide-based solid electrolyte can contain a Li element, an M element (M is a metal other than Li), and an X element (X is a halogen). Examples of X include, for example, F, Cl, Br, and I. In particular, for the halide-based solid electrolyte, at least one of Br and Cl is suitable as X. Examples of M include metal elements such as Sc, Y, B, Al, Ga, and In.

[0075] The composition of the halide-based solid electrolyte is not particularly limited, but Li 6-3a M a Br b Cl c (where M is a metal other than Li, 0 < a < 2, 0 ≤ b ≤ 6, 0 ≤ c ≤ 6, b + c = 6). At this time, a may be 0.75 or more, may be 1 or more, and a may be 1.5 or less. b may be 1 or more, may be 2 or more. Also, c may be 3 or more, may be 4 or more. Specific examples of the halide-based solid electrolyte include Li3YBr6, Li3YCl6, or Li3YBr2Cl4.

[0076] The solid electrolyte is in particulate form, and the average particle size (D50) may be 5.0 μm or less. For example, it may be 0.1 μm to 5.0 μm, 0.5 μm to 5.0 μm, 0.5 μm to 4.0 μm, 0.5 μm to 3.0 μm, 0.5 μm to 2.0 μm, or 0.5 μm to 1.0 μm.

[0077] The solid electrolyte layer may further contain a binder in addition to the solid electrolyte. In this case, the binder may be styrene-butadiene rubber, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, acrylate polymers, or combinations thereof, but is not limited to these, and any binder used in the art may be used. The acrylate polymer may be, for example, butyl acrylate, polyacrylate, polymethacrylate, or combinations thereof.

[0078] A solid electrolyte layer can be formed by adding a solid electrolyte to a binder solution, coating a substrate film with this solution, and drying it. The solvent for the binder solution may be isobutyryl isobutyrate, xylene, toluene, benzene, hexane, or a combination thereof, or it may be the compound represented by chemical formula 1 and / or the compound represented by chemical formula 2. The solid electrolyte layer formation process is widely known in the art, so a detailed explanation is omitted.

[0079] The thickness of the solid electrolyte layer may be, for example, 10 μm to 150 μm.

[0080] The solid electrolyte layer may further contain alkali metal salts and / or ionic liquids and / or conductive polymers.

[0081] The alkali metal salt may be, for example, a lithium salt. The lithium salt content in the solid electrolyte layer may be 1M or more, for example, 1M to 4M. In this case, the lithium salt can improve the ionic conductivity by improving the lithium ion mobility of the solid electrolyte layer.

[0082] Lithium salts include, for example, LiSCN, LiN(CN)2, Li(CF3SO2)3C, LiC4F9SO3, LiN(SO2CF2CF3)2, LiCl, LiF, LiBr, LiI, LiB(C2O4)2, LiBF4, LiBF3(C2F5), lithium bis(oxalato)borate (LiBOB), lithium oxalyldifluoroborate (LIODFB), lithium difluoro(oxalato)borate (LiDFOB), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI, LiN(SO2CF3)2), and lithium bis(fluorosulfonyl)imide (lithium It may contain bis(fluorosulfonyl)imide, LiFSI, LiN(SO2F)2, LiCF3SO3, LiAsF6, LiSbF6, LiClO4, or mixtures thereof.

[0083] Furthermore, the lithium salt may be imide-based; for example, imide-based lithium salts include lithium bis(trifluoromethanesulfonyl)imide (LiTFSI, LiN(SO2CF3)2) and lithium bis(fluorosulfonyl)imide (LiFSI, LiN(SO2F)2). The lithium salt can maintain or improve ionic conductivity by appropriately maintaining chemical reactivity with ionic liquids.

[0084] Ionic liquids are salts or room-temperature molten salts that have a melting point below room temperature and are in a liquid state at room temperature, yet are composed solely of ions.

[0085] The ionic liquid consists of a) one or more cations selected from ammonium, pyrrolidinium, pyridinium, pyrimidinium, imidazolium, piperidinium, pyrazolium, oxazolium, pyridazinium, phosphonium, sulfonium, triazolium, and mixtures thereof, and b) BF4 - PF6 - AsF6 - SbF6 - AlCl4 - HSO4 - ClO4 - CH3SO3 - CF3CO2 - Cl - , Br - , I - BF4 - SO4 - CF3SO3 - , (FSO2)2N - (C2F5SO2)2N - ,(C2F5SO2)(CF3SO2)N - , and (CF3SO2)2N - It may also be a compound containing one or more anions selected from among them.

[0086] The ionic liquid may be one or more selected from the group consisting of, for example, N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide, N-butyl-N-methylpyrrolidinium bis(3-trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide, and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide.

[0087] In the solid electrolyte layer, the weight ratio of the solid electrolyte to the ionic liquid may be 0.1:99.9 to 90:10, for example, 10:90 to 90:10, 20:80 to 90:10, 30:70 to 90:10, 40:60 to 90:10, or 50:50 to 90:10. A solid electrolyte layer satisfying the above range can improve the electrochemical contact area with the electrodes and maintain or improve ionic conductivity. This can improve the energy density, discharge capacity, rate-limiting characteristics, etc., of the all-solid-state battery.

[0088] An all-solid-state battery according to one embodiment can also be described as an all-solid-state secondary battery or an all-solid-state lithium secondary battery.

[0089] In one embodiment of the all-solid-state battery, during charging, lithium ions are released from the positive electrode active material, pass through the solid electrolyte, and move to the negative electrode side. As a result, they are deposited on the negative electrode current collector, forming a lithium deposition layer. That is, the lithium deposition layer is formed between the negative electrode current collector and the negative electrode catalyst layer.

[0090] The charging process may be a chemical conversion process carried out one to three times at approximately 25°C to 50°C and 0.05C to 1C.

[0091] The thickness of the lithium deposition layer may be 10 μm to 50 μm. For example, the thickness of the lithium deposition layer may be 10 μm or more, 20 μm or more, 30 μm or more, or 40 μm or more, and may be 50 μm or less, 40 μm or less, 30 μm or less, or 20 μm or less. When the thickness of the lithium deposition layer falls within the above range, there is an advantage that lithium can be reversibly deposited during charging / discharging, further improving the lifespan.

[0092] In one embodiment, a buffer material may be additionally included to cushion the thickness changes that occur during charging and discharging of the all-solid-state battery. The buffer material can be placed between the negative electrode and the case, and in the case of a battery in which one or more electrode assemblies are stacked, it can be placed between different electrode assemblies.

[0093] Examples of cushioning materials include substances with an elastic recovery rate of 50% or more and insulating properties, specifically including silicone rubber, acrylic rubber, fluorocarbon rubber, nylon, synthetic rubber, or combinations thereof. Cushioning materials may exist in the form of polymer sheets.

[0094] Figure 1 is a cross-sectional view of an all-solid-state battery according to one embodiment. Referring to Figure 1, the all-solid-state battery 100 may have a structure in which an electrode assembly is constructed by stacking a negative electrode 400 including a negative electrode current collector 401 and a negative electrode active material layer 403, a solid electrolyte layer 300, and a positive electrode 200 including a positive electrode active material layer 203 and a positive electrode current collector 201, and this assembly is housed in a case such as a pouch. The all-solid-state battery 100 may further include an elastic layer 500 on the outside of at least one of the positive electrode 200 and the negative electrode 400. Although Figure 1 shows one electrode assembly including a negative electrode 400, a solid electrolyte layer 300, and a positive electrode 200, an all-solid-state battery can also be manufactured by stacking two or more electrode assemblies.

[0095] Figure 2 schematically shows the structure of a fully charged all-solid-state battery. The all-solid-state battery 100 includes a positive electrode 200 containing a positive electrode current collector 201 and a positive electrode active material layer 203, a negative electrode 400 containing a negative electrode current collector 401 and a negative electrode catalyst layer 403, and a solid electrolyte layer 300 located between the positive electrode 200 and the negative electrode 400, and includes a battery case 500 in which these are housed.

[0096] When such a solid-state battery 100 is charged, as shown in Figure 2, lithium ions are released from the positive electrode active material and deposited onto the negative electrode current collector 401', resulting in the formation of a lithium deposition layer 405' between the current collector 401' and the negative electrode catalyst layer 403''.

[0097] Examples and comparative examples of the present invention are described below. However, the following examples are merely one embodiment of the present invention, and the present invention is not limited to these examples. [Examples]

[0098] (Example 1) (1) Manufacturing of the negative electrode A negative electrode catalyst layer slurry was prepared by mixing 8 wt% Li-carboxymethylcellulose binder, 5 wt% Ag nanoparticles (D50:60 nm), 86 wt% carbon black, and 5 wt% Nb2O in an aqueous solvent. The carbon black was a mixture of single particles with a particle size of 38 nm and secondary particles, where the secondary particles were assembled from primary particles with a particle size of 76 nm, resulting in secondary particles with a particle size of 275 nm.

[0099] The slurry was coated onto a stainless steel foil current collector, and then vacuum-dried at 100°C to produce a negative electrode containing a 5 μm thick negative electrode catalyst layer and a 10 μm thick current collector.

[0100] (2) Manufacturing of the positive electrode LiRing 0.8 Co 0.1 Al 0.1 A cathode active material layer slurry was prepared by mixing 85.00 wt% O2 cathode active material, 13.5 wt% argyrodite-type solid electrolyte Li6PS5Cl, 0.5 wt% carbon nanotube conductive material, and 1.0 wt% polyvinylidene fluoride binder in an N-methylpyrrolidone solvent.

[0101] The positive electrode active material layer slurry was coated onto an aluminum current collector, and a drying and rolling process was carried out at 60°C to manufacture a positive electrode for an all-solid-state battery.

[0102] (3) Manufacturing of the solid electrolyte layer An isobutylyl isobutylate binder solution (solid content: 50% by weight), which contains butyl acrylate (an acrylate-based polymer), was added to an argyrodite-type solid electrolyte, Li6PS5Cl, and mixed. At this time, the mixing ratio of the solid electrolyte to the binder was 98.7:1.3 by weight.

[0103] The mixing process was carried out using a Thinky mixer. A 2 mm zirconia ball was added to the resulting mixture and stirred again in the Thinky mixer to produce a slurry. The slurry was cast onto a release polytetrafluoroethylene film and dried at room temperature to produce a solid electrolyte with a solid electrolyte layer thickness of 5 μm.

[0104] (3) Manufacturing of all-solid-state batteries The manufactured negative electrode, solid electrolyte, and positive electrode were sequentially stacked, and a pressure of 2 Nm was applied to produce an all-solid-state battery. In the manufactured battery, the thickness of the positive electrode active material layer or lithium (excluding the current collector) was 100-150 μm, the thickness of the negative electrode catalyst layer (excluding the current collector) was 5-10 μm, and the thickness of the solid electrolyte layer was 100 μm.

[0105] (Example 2) The anode was manufactured in the same manner as in Example 1, except that 8% by weight of a mixed binder of Li-carboxymethylcellulose (Li-CMC) and styrene-butadiene rubber (SBR) (Li-CMC:SBR = 1:2 by weight ratio), 4% by weight of Ag nanoparticles (D50:60nm), 85% by weight of carbon black, and 53% by weight of Nb2O were mixed in an aqueous solvent to produce a slurry for the anode catalyst layer.

[0106] An all-solid-state battery was manufactured using the negative electrode, the positive electrode manufactured in Example 1, and the solid electrolyte, in the same manner as in Example 1.

[0107] (Example 3) The anode was manufactured in the same manner as in Example 1, except that 8% by weight of a mixed binder of Li-carboxymethylcellulose (Li-CMC) and styrene-butadiene rubber (SBR) (Li-CMC:SBR = 1:2 by weight ratio), 4% by weight of Ag nanoparticles (D50:60nm), 83% by weight of carbon black, and 55% by weight of Nb2O were mixed in an aqueous solvent to produce a negative electrode catalyst layer slurry.

[0108] An all-solid-state battery was manufactured using the negative electrode, the positive electrode manufactured in Example 1, and the solid electrolyte, in the same manner as in Example 1.

[0109] (Example 4) The anode was manufactured in the same manner as in Example 1, except that 8% by weight of a mixed binder of Li-carboxymethylcellulose (Li-CMC) and styrene-butadiene rubber (SBR) (Li-CMC:SBR = 1:2 by weight ratio), 4% by weight of Ag nanoparticles (D50:60nm), 78% by weight of carbon black, and 10% by weight of Nb2O5 were mixed in an aqueous solvent to produce a negative electrode catalyst layer slurry.

[0110] An all-solid-state battery was manufactured using the negative electrode, the positive electrode manufactured in Example 1, and the solid electrolyte, in the same manner as in Example 1.

[0111] (Example 5) The anode was manufactured in the same manner as in Example 1, except that 8% by weight of a mixed binder of Li-carboxymethylcellulose (Li-CMC) and styrene-butadiene rubber (SBR) (Li-CMC:SBR = 1:2 by weight ratio), 3% by weight of Ag nanoparticles (D50:60nm), 64% by weight of carbon black, and 25% by weight of Nb2O5 were mixed in an aqueous solvent to produce a negative electrode catalyst layer slurry.

[0112] An all-solid-state battery was manufactured using the negative electrode, the positive electrode manufactured in Example 1, and the solid electrolyte, in the same manner as in Example 1.

[0113] (Example 6) The anode was manufactured in the same manner as in Example 1, except that 8% by weight of a mixed binder of Li-carboxymethylcellulose (Li-CMC) and styrene-butadiene rubber (SBR) (Li-CMC:SBR = 1:2 by weight ratio), 3% by weight of Ag nanoparticles (D50:60nm), 59% by weight of carbon black, and 530% by weight of Nb2O were mixed in an aqueous solvent to produce a negative electrode catalyst layer slurry.

[0114] An all-solid-state battery was manufactured using the negative electrode, the positive electrode manufactured in Example 1, and the solid electrolyte, in the same manner as in Example 1.

[0115] (Example 7) The anode was manufactured in the same manner as in Example 1, except that 8% by weight of a Li-carboxymethylcellulose (Li-CMC) and styrene-butadiene rubber (SBR) mixed binder (Li-CMC:SBR = 1:2 by weight ratio), 82% by weight of carbon black, and 10% by weight of Nb2O5 were mixed in an aqueous solvent to produce a negative electrode catalyst layer slurry.

[0116] An all-solid-state battery was manufactured using the negative electrode, the positive electrode manufactured in Example 1, and the solid electrolyte, in the same manner as in Example 1.

[0117] (Example 8) The anode was manufactured in the same manner as in Example 1, except that 8% by weight of a mixed binder of Li-carboxymethylcellulose (Li-CMC) and styrene-butadiene rubber (SBR) (Li-CMC:SBR = 1:2 by weight ratio), 62% by weight of carbon black, and 30% by weight of Nb2O were mixed in an aqueous solvent to produce a negative electrode catalyst layer slurry.

[0118] An all-solid-state battery was manufactured using the negative electrode, the positive electrode manufactured in Example 1, and the solid electrolyte, in the same manner as in Example 1.

[0119] (Comparative Example 1) The anode was manufactured in the same manner as in Example 1, except that 8% by weight of a mixed binder of Li-carboxymethylcellulose (Li-CMC) and styrene-butadiene rubber (SBR) (Li-CMC:SBR = 1:2 by weight ratio), 4.2% by weight of Ag nanoparticles (D50:60nm), 87% by weight of carbon black, and 50.8% by weight of Nb2O were mixed in an aqueous solvent to produce a slurry for the anode catalyst layer.

[0120] An all-solid-state battery was manufactured using the negative electrode, the positive electrode manufactured in Example 1, and the solid electrolyte, in the same manner as in Example 1.

[0121] (Comparative Example 2) The anode was manufactured in the same manner as in Example 1, except that 8% by weight of a mixed binder of Li-carboxymethylcellulose (Li-CMC) and styrene-butadiene rubber (SBR) (Li-CMC:SBR = 1:2 by weight ratio), 3% by weight of Ag nanoparticles (D50:60nm), 57% by weight of carbon black, and 32% by weight of Nb2O were mixed in an aqueous solvent to produce a negative electrode catalyst layer slurry.

[0122] (Comparative Example 3) The anode was manufactured in the same manner as in Example 1, except that 8% by weight of a mixed binder of Li-carboxymethylcellulose (Li-CMC) and styrene-butadiene rubber (SBR) (Li-CMC:SBR = 1:2 by weight ratio), 2% by weight of Ag nanoparticles (D50:60nm), 40% by weight of carbon black, and 550% by weight of Nb2O were mixed in an aqueous solvent to produce a slurry for the anode catalyst layer.

[0123] (Comparative Example 4) The anode was manufactured in the same manner as in Example 1, except that 8% by weight of a mixed binder of Li-carboxymethylcellulose (Li-CMC) and styrene-butadiene rubber (SBR) (Li-CMC:SBR = 1:2 by weight ratio), 60% by weight of carbon black, and 32% by weight of Nb2O5 were mixed in an aqueous solvent to produce a slurry for the anode catalyst layer.

[0124] (Comparative Example 5) Using the negative electrode from Example 1, an all-solid-state battery with an N / P ratio of 0.09 was manufactured by adjusting the loading level of the negative electrode.

[0125] (Comparative Example 6) Using the negative electrode from Example 1, an all-solid-state battery with an N / P ratio of 0.5 was manufactured by adjusting the loading level of the negative electrode.

[0126] (Comparative Example 7) Using the negative electrode from Example 6, an all-solid-state battery with an N / P ratio of 0.09 was manufactured by adjusting the loading level of the negative electrode.

[0127] (Comparative Example 8) Using the negative electrode from Example 6, an all-solid-state battery with an N / P ratio of 0.5 was manufactured by adjusting the loading level of the negative electrode.

[0128] Experimental Example 1) Electrical Resistance Evaluation The electrical resistance (surface resistance) of the negative electrodes manufactured in Examples 1 to 8 and Comparative Examples 1 to 8 was measured by probes at 46 pins using a 4-probe method (XF057, HIOKI Corporation), and the results are shown in Table 2 below.

[0129] Experimental Example 2) Surface Roughness Evaluation The surface roughness (Ra) of the negative electrodes manufactured in Examples 1-8 and Comparative Examples 1-8 was measured, and the results are shown in Table 2 below. Surface roughness is the average value obtained by summing the absolute values ​​of the deviations from the reference surface to the measurement surface; that is, it is the value obtained by calculating the average of the absolute values ​​of the difference between all points on the surface and the reference surface. This surface roughness was measured using a 3D optical microscope (optical microscopy, Keyence).

[0130] Experimental Example 3) Overvoltage Evaluation The all-solid-state batteries manufactured in Examples 1-8 and Comparative Examples 1-8 were charged at 0.05C, and a voltage drop began at OCV (Open Circuit Voltage, approximately 2.5V). Next, the voltage was measured up to the point where an inflection point occurred around 0mV. This result is shown as overvoltage in Table 2 below.

[0131] Experimental Example 4) Evaluation of Initial Efficiency For the all-solid-state batteries manufactured according to Examples 1-8 and Comparative Examples 1-8, one 0.05C charge-discharge cycle was performed, and the percentage of discharge capacity to charge capacity was determined. The results are shown in Table 2 below as the initial efficiency.

[0132] Experimental Example 5) Evaluation of Output Efficiency The all-solid-state batteries manufactured according to Examples 1-6 and Comparative Examples 1-4 were subjected to 0.05C charging and 0.1C discharging. The percentage value of the discharge capacity relative to the charge capacity was calculated, and the results are shown in Table 2 below as the output efficiency.

[0133] The negative electrode catalyst layer compositions of Examples 1 to 8 and Comparative Examples 1 to 4 are summarized in Table 1 below.

[0134] Furthermore, the N / P ratios of the manufactured all-solid-state batteries are shown in Table 1 below. In this case, the N / P ratio was determined as the ratio of the capacity of the negative electrode catalyst layer to the capacity (theoretical capacity) of the positive electrode. The theoretical capacity of the negative electrode catalyst layer was obtained by charging a half-cell manufactured using the negative electrodes of Examples 1 to 8 and Comparative Examples 1 to 8, the solid electrolyte layer, and the lithium counter electrode once at 0.05C and measuring the capacity up to the inflection point near 0mV (vs.Li).

[0135] [Table 1]

[0136] [Table 2]

[0137] As shown in Table 2 above, Examples 1 to 8, which contain 1% to 30% by weight of Nb2O5 in the negative electrode catalyst layer and have an N / P ratio of 0.1 or higher and less than 0.5, exhibit low electrical resistance and surface roughness, while also showing low overpotential and excellent initial efficiency and output efficiency.

[0138] On the other hand, in Comparative Example 1, where an excessively small amount of Nb2O5 was used, the initial efficiency deteriorated and a short circuit occurred.

[0139] Furthermore, in Comparative Example 2, which used 32% by weight of Nb2O5, electrical resistance and surface roughness increased, and overvoltage rise and deterioration of initial efficiency occurred. In particular, in Comparative Example 3, which used an excessively large amount of Nb2O5 (50% by weight), electrical resistance and surface roughness increased significantly, initial efficiency deteriorated considerably, and a short circuit occurred. In Comparative Example 4, which did not use Ag, high electrical resistance and surface roughness were observed, along with low overvoltage, low initial efficiency, and a short circuit.

[0140] Comparative Examples 5 and 7 show an N / P ratio of less than 0.1, indicating that even with the use of 1% and 30% by weight of Nb2O5, they exhibit somewhat low initial efficiency and degraded output efficiency. In Comparative Examples 6 and 8, the N / P ratio is 0.5 or higher, and even with the use of 1% and 30% by weight of Nb2O5, the resistance is excessively high and unmeasurable, indicating very degraded initial efficiency and the occurrence of a short circuit.

[0141] Experimental Example 6) SEM images and EDAX The negative electrode manufactured according to Example 1 was cross-polished to flatten its cross-section. A surface SEM image of the obtained negative electrode is shown in Figure 3. The EDAX measurement results for the negative electrode are shown in Figure 4.

[0142] Furthermore, Figure 5 shows a 20,000x magnified image of the SEM photograph in Figure 3. Figure 6 also shows the EDAX measurement results for selected area 1 and selected area 2 in Figure 5.

[0143] The EDAX results in Figure 4 show that Nb2O5 is present in the negative electrode of Example 1.

[0144] Furthermore, in the SEM image shown in Figure 3, the bright colored dots are Nb2O5, which is clearly evident from the fact that while C, O, and Nb peaks are present in Figure 6, which is the EDAX result for selected area 1 in Figure 5, only a C peak is present in Figure 6, which is the EDAX result for selected area 2 in Figure 5.

[0145] While preferred embodiments of the present invention have been described above, the present invention is not limited thereto. It can be implemented in various ways within the scope of the claims, the detailed description of the invention, and the attached drawings, and these also naturally fall within the scope of the present invention.

Claims

1. A positive electrode containing a positive electrode active material layer containing a positive electrode active material; Negative electrode catalyst and Nb 2 O 5 A negative electrode comprising a negative electrode catalyst layer containing; and It contains an electrolyte layer, The aforementioned Nb 2 O 5 The content is 1% to 30% by weight relative to 100% by weight of the entire negative electrode catalyst layer. An all-solid-state battery in which the ratio (N / P) of the capacity of the negative electrode catalyst layer to the capacity of the positive electrode is 0.1 or more and less than 0.

5.

2. The aforementioned Nb 2 O 5 The all-solid-state battery according to claim 1, wherein the content of is 3% to 30% by weight relative to 100% by weight of the entire negative electrode catalyst layer.

3. The aforementioned Nb 2 O 5 The all-solid-state battery according to claim 1, wherein the content of is 5% to 15% by weight relative to 100% by weight of the entire negative electrode catalyst layer.

4. The all-solid-state battery according to claim 1, wherein the ratio (N / P) of the capacity of the negative electrode catalyst layer to the capacity of the positive electrode is 0.1 to 0.

4.

5. The all-solid-state battery according to claim 1, wherein the ratio (N / P) of the capacity of the negative electrode catalyst layer to the capacity of the positive electrode is 0.1 to 0.

3.

6. The all-solid-state battery according to claim 1, wherein the negative electrode catalyst is a carbon-based material, metal particles, or a combination thereof.

7. The all-solid-state battery according to claim 6, wherein the carbon-based material is amorphous carbon.

8. The all-solid-state battery according to claim 6, wherein the metal particles are any one selected from Ag, Zn, Al, Sn, Mg, Ge, Cu, In, Ni, Bi, Au, Si, Pt, Pd, and combinations thereof.

9. The all-solid-state battery according to claim 1, wherein the electrolyte layer includes a solid electrolyte.

10. The all-solid-state battery according to claim 9, wherein the solid electrolyte is a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a halide-based solid electrolyte, or a solid polymer electrolyte.

11. The negative electrode further includes a current collector that supports the negative electrode catalyst layer, The all-solid-state battery according to claim 1, further comprising a lithium deposition layer formed between the current collector and the negative electrode catalyst layer during initial charging.

12. The all-solid-state battery according to claim 1, wherein the positive electrode active material is a positive electrode active material or sulfur-based compound capable of reversibly intercepting and releasing lithium ions.

13. The all-solid-state battery according to claim 12, wherein the positive electrode active material is a positive electrode active material capable of reversibly intercepting and releasing lithium ions.

Images