Positive electrode, manufacturing method thereof, and all-solid-state rechargeable batteries

Abstract

The present invention relates to a positive electrode, a manufacturing method thereof, and all-solid-state rechargeable batteries, the positive electrode comprising a positive electrode current collector and a positive electrode active material layer positioned on the positive electrode current collector, wherein the positive electrode active material layer includes a positive electrode active material, a sulfide-based solid electrolyte, a binder and a conductive material, the conductive material includes carbon nanotubes and carbon nanoparticles, and, on the basis of 100 wt% of the total of the carbon nanotubes and the carbon nanoparticles, the carbon nanotubes are includes in the amount of 40-90 wt% and the carbon nanoparticles are included in the amount of 10-60 wt%.

Description

Anode, its manufacturing method and all-solid-state secondary battery

[0001] It relates to a cathode, a method for manufacturing the same, and an all-solid-state secondary battery.

[0002] Lithium secondary batteries, which offer high energy density and portability, are primarily used as power sources for mobile information terminals such as mobile phones, laptops, and smartphones. Recently, active research is underway to utilize high-energy-density lithium secondary batteries as power sources for hybrid and electric vehicles, or as power storage devices.

[0003] Commercially available lithium secondary batteries use electrolytes containing flammable organic solvents, posing safety concerns that can lead to explosions or fires in the event of collisions or penetrations. Therefore, all-solid-state secondary batteries, which utilize solid electrolytes instead of the electrolyte, are being proposed. All-solid-state secondary batteries are comprised entirely of solid materials, eliminating the risk of electrolyte leakage and explosion, and are also advantageous in that they can be easily manufactured into thin batteries.

[0004] The positive electrode of an all-solid-state secondary battery contains various organic and inorganic materials, including a positive electrode active material, a solid electrolyte, a conductive agent, and a binder. However, among solid electrolytes, sulfide-based solid electrolytes, which exhibit excellent ionic conductivity, are susceptible to deterioration in air, moisture, polar solvents, or at high temperatures, potentially affecting the performance of the all-solid-state battery.

[0005] According to one embodiment, a cathode and an all-solid-state secondary battery are provided that can improve the dispersibility of a slurry and enhance conductivity. Alternatively, according to one embodiment, a cathode and an all-solid-state secondary battery are provided that can improve the quality and productivity of a cathode plate.

[0006] In one embodiment, a positive electrode is provided, comprising: a positive electrode current collector; and a positive electrode active material layer positioned on the positive electrode current collector; wherein the positive electrode active material layer includes a positive electrode active material, a sulfide-based solid electrolyte, a binder, and a conductive material, wherein the conductive material includes carbon nanotubes and carbon nanoparticles, and the carbon nanotubes are included in an amount of 40 wt% to 90 wt% and the carbon nanoparticles are included in an amount of 10 wt% to 60 wt% based on 100 wt% of the total of the carbon nanotubes and carbon nanoparticles.

[0007] In another embodiment, a method for manufacturing a positive electrode is provided, which comprises dry mixing a positive electrode active material, a sulfide-based solid electrolyte, and carbon nanoparticles, adding a binder and carbon nanotubes to the resultant dry mixture, and mixing them to obtain a positive electrode active material slurry, wherein the carbon nanotubes are added in an amount of 40 to 90 wt% and the carbon nanoparticles are added in an amount of 10 to 60 wt%, based on 100 wt% of the total of the carbon nanotubes and carbon nanoparticles.

[0008] In another embodiment, an all-solid-state secondary battery is provided, comprising the above-described positive electrode; a negative electrode; and a solid electrolyte layer positioned between the positive electrode and the negative electrode.

[0009] According to one embodiment, a cathode and an all-solid-state secondary battery capable of improving the dispersibility and conductivity of a slurry can be provided. In addition, according to one embodiment, a cathode capable of improving the quality and productivity of a cathode plate, a method for manufacturing the same, and an all-solid-state secondary battery can be provided.

[0010] Figures 1 and 2 are cross-sectional views schematically showing an all-solid-state secondary battery according to one embodiment.

[0011] Figure 3 is a schematic diagram schematically showing a positive electrode active material layer of an all-solid-state secondary battery according to a comparative example.

[0012] Figure 4 is a schematic diagram schematically showing the clustering tendency of carbon nanoparticles according to one embodiment.

[0013] Figure 5 is a schematic diagram schematically showing a positive electrode active material layer of an all-solid-state secondary battery according to one embodiment.

[0014] Figure 6 is an image of a cross-section of a positive electrode active material layer manufactured in Comparative Example 1, taken with a scanning electron microscope (SEM) at a magnification of 10,000 times.

[0015] Figure 7 is a graph showing the change in viscosity according to the shear rate (1 / s) of the positive electrode active material slurry obtained from Comparative Examples 1 and 2 and Examples 1 and 2.

[0016] Figure 8 is an enlarged view showing the square portion of Figure 7.

[0017] Figure 9 is a graph showing the results of measuring electronic conductivity and ionic conductivity through electrochemical impedance spectroscopy (EIS) for the anodes obtained from Comparative Examples 1 to 3 and Examples 1 and 2.

[0018] Figure 10 is a graph showing changes in discharge capacity for all-solid-state secondary batteries manufactured in Comparative Example 1 and Examples 1 and 2.

[0019] Figure 11 is a graph showing the measurement results of the average discharge voltage for all-solid-state secondary batteries manufactured in Comparative Example 1 and Examples 1 and 2.

[0020] Hereinafter, embodiments of the present invention will be described in detail. However, these are presented as examples and are not intended to limit the present invention. The present invention is defined solely by the scope of the claims set forth below.

[0021] Unless otherwise specified herein, when a part such as a layer, film, region, plate, etc. is said to be “on” another part, this includes not only cases where it is “directly on” the other part, but also cases where there is another part in between.

[0022] Unless otherwise specified herein, the singular may also include the plural. Furthermore, unless otherwise specified, "A or B" may mean "including A, including B, or including A and B."

[0023] As used herein, “combination thereof” may mean mixtures, laminates, composites, copolymers, alloys, blends, and reaction products of the components.

[0024] Unless otherwise defined herein, the particle size may be the average particle size. In addition, the particle size refers to the average particle size (D50), which means the diameter of particles with a cumulative volume of 50% by volume in a particle size distribution. The average particle size (D50) can be measured by a method well known to those skilled in the art, for example, by measuring with a particle size analyzer, or by measuring with a transmission electron microscope (TEM) photograph or a scanning electron microscope (SEM) photograph. Alternatively, the average particle size (D50) value can be obtained by measuring with a measuring device that utilizes dynamic light-scattering, performing data analysis to count the number of particles for each particle size range, and calculating from the counted number. Alternatively, the average particle size (D50) value can be obtained by measuring with a laser diffraction method. When measuring by laser diffraction, more specifically, after the particles to be measured are dispersed in a dispersion medium, they are introduced into a commercially available laser diffraction particle size measuring device (e.g., Microtrac MT 3000) and irradiated with ultrasonic waves of approximately 28 kHz at an output of 60 W, and the average particle size (D50) based on 50% of the particle size distribution in the measuring device can be calculated.

[0025] anode

[0026] In one embodiment, a positive electrode is provided, comprising: a positive electrode current collector; and a positive electrode active material layer positioned on the positive electrode current collector; wherein the positive electrode active material layer includes a positive electrode active material, a sulfide-based solid electrolyte, a binder, and a conductive material, wherein the conductive material includes carbon nanotubes and carbon nanoparticles, and the carbon nanotubes are included in an amount of 40 wt% to 90 wt% and the carbon nanoparticles are included in an amount of 10 wt% to 60 wt% based on 100 wt% of the total of the carbon nanotubes and carbon nanoparticles.

[0027] The above-mentioned positive electrode active material layer includes a positive electrode active material, a sulfide-based solid electrolyte, a binder, and a conductive agent. That is, the positive electrode slurry of an all-solid-state secondary battery is composed of various organic and inorganic materials such as a positive electrode active material, a solid electrolyte, a conductive agent, and a binder. Among the solid electrolytes, a sulfide-based solid electrolyte with excellent ionic conductivity is used. However, the sulfide-based solid electrolyte has the characteristic of being easily deteriorated by air, moisture, polar solvents, or high temperatures. Therefore, when using a sulfide-based solid electrolyte, a low-polarity solvent is used instead of a polar solvent due to reactivity. Carbon nanotubes are used as a conductive agent due to their excellent electrochemical properties, but their strong interactions easily cause agglomeration in the solution. This agglomeration of carbon nanotubes can increase the viscosity of the positive electrode slurry, which can lower the storage stability of the slurry and the production quality of the electrode plate, as well as reduce the conductivity. Accordingly, there is a method to improve the phase stability of the slurry by increasing the dispersibility of the carbon nanotubes themselves, but there is a limitation due to the low dispersibility of the carbon nanotubes in the low-polarity solvent adopted in consideration of the reactivity of the sulfide-based solid electrolyte.

[0028] In one embodiment, we propose a cathode that can improve the dispersibility of slurry and the conductivity of a battery, and enhance the quality and productivity of the electrode plate.

[0029] Challenge

[0030] The above-described positive electrode active material layer includes carbon nanotubes and carbon nanoparticles as conductive agents. FIG. 3 is a schematic diagram of a positive electrode active material layer of an all-solid-state secondary battery according to a comparative example, in which the positive electrode active material layer includes only carbon nanotubes as conductive agents and no carbon nanoparticles. In addition, FIG. 5 is a schematic diagram of a positive electrode active material layer of an all-solid-state secondary battery according to an embodiment. As can be seen in FIG. 3, ions move through the solid electrolyte (2) to secure an ion conduction path, and the connection between the positive electrode active material (1) and the carbon nanotubes (11), which are conductive agents, is secured through the carbon nanotubes (11), thereby securing an electron conduction path. However, carbon nanotubes may be dispersed in an uneven form within the positive electrode active material layer, and thus their utility in terms of conductivity is somewhat limited. On the other hand, carbon nanoparticles such as carbon black may be advantageous over carbon nanotubes in terms of dispersibility. Accordingly, in one embodiment, carbon nanoparticles, such as carbon black, are mixed with carbon nanotubes as a conductive material to perform an auxiliary role within the anode, thereby enhancing the network of electronic and ionic conduction without impeding the connectivity of the solid electrolyte. Accordingly, as can be seen in Fig. 5, by using carbon nanoparticles (12) together with carbon nanotubes (11) as a conductive material within the anode active material layer, a more uniform and denser path for electronic conduction can be secured compared to the case of Fig. 3.

[0031] For example, the carbon nanotubes may be single-walled carbon nanotubes (SWCNTs), double-walled carbon nanotubes (DWCNTs), multi-walled carbon nanotubes (MWCNTs), or a combination thereof. Alternatively, the carbon nanotubes may be short-length carbon nanotubes (S-CNTs), long-length carbon nanotubes (L-CNTs), or a combination thereof, and may particularly be L-CNTs. When such carbon nanotubes are used as conductive materials in the positive electrode active material layer, the connectivity between the positive electrode active material and the conductive material distributed between the solid electrolytes can be secured, thereby improving the electronic network.

[0032] The carbon nanoparticles may be, for example, carbon black, acetylene black, Ketjen black, Denka black, or a combination thereof. When using the carbon nanoparticles, not only is it advantageous in terms of securing the dispersibility of the slurry compared to when using only carbon nanotubes, but it is also convenient in terms of the manufacturing process because there is no need to produce the slurry in the form of a pre-dispersed liquid.

[0033] In the above positive electrode active material layer, the carbon nanotubes are included in an amount of 40 to 90 wt%, and the carbon nanoparticles are included in an amount of 10 to 60 wt%, based on 100 wt% of the total of the carbon nanotubes and carbon nanoparticles. Within this range, the dispersibility within the positive electrode slurry can be improved, while maintaining a balance between electronic conduction and ionic conduction, thereby lowering the resistance of the electrode plate, improving cell performance, and also ensuring structural stability.

[0034] According to one embodiment, within the positive electrode active material layer, the carbon nanoparticles may form aggregates by connecting primary particles to each other. Alternatively, the primary particles and aggregates may gather together to form clusters. In this case, the aggregate size of the carbon nanoparticles within the positive electrode active material layer can be expanded from nanometers to micrometers, thereby harmoniously enhancing electronic conductivity and ionic conductivity.

[0035] Fig. 4 is a schematic diagram of the clustering tendency of carbon nanoparticles in a positive electrode active material layer according to one embodiment. In the positive electrode active material layer, the carbon nanoparticles may have primary particles such as A of Fig. 4 connected to each other to form aggregates such as B of Fig. 4. In addition, the primary particles and aggregates may gather to form aggregates such as C of Fig. 4. In this case, the aggregates may be formed by the primary particles and aggregates being held together by a weaker attractive force than the aggregates. In this case, the carbon nanoparticles in the positive electrode active material layer may be connected to secure a more uniform and dense path for electron conduction, and the network for electron conduction may be improved throughout the positive electrode active material layer.

[0036] According to one embodiment, the average particle diameter (D50) of the primary particles of the carbon nanoparticles may be 1 nm to 50 nm, for example, 3 nm to 45 nm, 5 nm to 43 nm, or 10 nm to 40 nm. Within the above range, electronic conductivity and ionic conductivity can be harmoniously improved without impairing the connectivity of the solid electrolyte.

[0037] The positive electrode active material layer may include a conductive material in an amount of 0.01 wt% to 5 wt% based on 100 wt% of the positive electrode active material layer.

[0038] According to one embodiment, the positive electrode active material layer may further include a low-polarity solvent having a polarity index (PI) of 0.074 to 0.281. When such a low-polarity solvent is used, the reactivity with the sulfide-based solid electrolyte is low, so that the cell resistance is not increased, thereby improving the performance of the battery. Here, the polarity may refer to a relative polarity when the polarity of water is set to 9.0, and values ​​of polarity disclosed in generally known literature may be used.

[0039] In one embodiment, the low-polarity solvent may have a polarity of 0.074 to 0.281 and may be selected from a pyridine solvent, a benzene solvent, an acetate solvent, a ketone solvent, an ester solvent, an ether solvent, a carbonate solvent, an acrylate solvent, an aldehyde solvent, a piperidine solvent, a sulfite solvent, an alkyl solvent, a formate solvent, or a combination thereof. The pyridine solvent is a solvent that includes a pyridine ring in its structure, and examples thereof include 2,6-di-tert-butylpyridine, 2-vinylpyridine, acetylpyridine, and 2-chloropyridine. The above benzene-based solvent is a solvent that contains a benzene ring in its structure, and examples thereof include bromobenzene, p-chlorotoluene, benzal chloride, N,N-dimethylaniline, styrene oxide, methoxybenzene (anisole), butyl benzonate, benzaldehyde, benzeneacetonitrile, etc. The above acetate-based solvent is a solvent that contains acetate in its structure, and examples thereof include ethyl chloroacetate, 2-ethylhexyl acetate, etc. The above ketone-based solvent is a solvent that contains a ketone group in its structure, and examples thereof include methyl isoamyl ketone, di-tert-butyl ketone, ethyl amyl ketone, diisobutal ketone, cyclopentanone, 4-heptanone, 5-methyl-3-heptanone, etc. The above ester solvent is a solvent that includes an ester group in its structure, and examples thereof include methyl laurate, n-butyl propionate, diketene, and methyl oleate. The above ether solvent is a solvent that includes an ether group in its structure, and examples thereof include 1,8-cineole. The above carbonate solvent is a solvent that includes a carbonate group in its structure, and examples thereof include diethyl carbonate and diethyl carbonate. The above acrylate solvent is a solvent that includes n-butyl acrylate, n-butyl methacrylate, and isobutyl methacrylate. The above aldehyde solvent is a solvent that includes an aldehyde group in its structure, and examples thereof include ethylhexaaldehyde.The piperidine solvent is a solvent that includes piperidine in its structure, and examples thereof include 1-formylpiperidine. The sulfite solvent is a solvent that includes sulfite in its structure, and examples thereof include ethylene sulfite. The alkyl solvent is a solvent that includes an alkyl group in its structure, and examples thereof include 1,2,3-trichloropropane and chlorocyclohexane. The formate solvent is a solvent that includes a formate group in its structure, and examples thereof include amyl formate.

[0040] For example, the positive electrode active material layer may contain 500 ppm or less of the low-polarity solvent with respect to 100 wt% of the positive electrode active material layer. Examples of such low polarity solvents include 2,6-di-tert-butylpyridine, bromobenzene, benzyl chloride, p-chlorotoluene, benzal chloride, o-dichlorobenzene, N,N-dimethylaniline, benzyl bromide, 1,2,3-trichloropropane, methoxybenzene (anisole), ethoxybenzene, 2-vinylpyridine, chlorocyclohexane, methyl laurate, ethyl chloroacetate, 2-ethylhexyl acetate, o-chlorobenzyl chloride, diethyl carbonate, ethyl trichloroacetate, n-butyl acrylate, methyl isoamyl ketone, di-tert-butyl ketone, styrene oxide, diketene, ethylhexaaldehyde, n-butyl methacrylate, diisopropyl ketone, sec-amyl acetate, methyl amyl acetate. n-butyl propionate, n-pentyl propionate, n-pentyl propionate, 1-formylpiperidine, butyl benzonate, 4-heptanone, 1,8-cineole, isobutyl methacrylate, benzeneacetonitrile, methyl benzoate, isobutyl isobutyrate, oxyl acetate, acetylpyridine, methyl oleate, methyl amyl ketone, 5-methyl-3-heptanone, amyl formate, diisobutyl ketone, ethyl amyl ketone, ethylene sulfite, dibutyl ketone, cyclopentanone, 2-chloropyridine, ethyl phenylacetate, diethyl carbonate, benzaldehyde, isoamyl acetate, methyl hexyl ketone, ethyl benzoate, phenyl acetate, or a combination thereof. When the aforementioned low-polarity solvent is used, it is possible to achieve an appropriate viscosity of the slurry without increasing cell resistance due to its low reactivity with the sulfide-based solid electrolyte, enable uniform coating within the electrode plate, and contribute to improving conductivity and battery performance.

[0041] positive electrode active material

[0042] A compound capable of reversible intercalation and deintercalation of lithium (a lithiated intercalation compound) can be used as the positive electrode active material. For example, one or more of a composite oxide of lithium and a metal selected from cobalt, manganese, nickel, and combinations thereof can be used.

[0043] The above composite oxide may be a lithium transition metal composite oxide, and specific examples thereof include lithium nickel-based oxide, lithium cobalt-based oxide, lithium manganese-based oxide, lithium iron phosphate-based compound, cobalt-free nickel-manganese-based oxide, lithium-rich layered oxide, or a combination thereof.

[0044] For example, the cathode active material may be a high-nickel cathode active material in which the nickel content is 80 mol% or more based on 100 mol% of metals excluding lithium in a lithium transition metal composite oxide. The nickel content in the high-nickel cathode active material may be 85 mol% or more, 90 mol% or more, 91 mol% or more, or 94 mol% or more, and 99 mol% or less based on 100 mol% of metals excluding lithium. The high-nickel cathode active material can realize high capacity and thus can be applied to high-capacity, high-density lithium secondary batteries.

[0045] As a more specific example, a compound represented by any one of the following chemical formulas may be used: Li a A 1-b X b O 2-c D c (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05); Li a Mn 2-b X b O 4-c D c (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.05); Li a Ni 1-b-c Co b X c O 2-α D α(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤0.5, 0 < α < 2);Li a Nor 1-b-c Mn b X c O 2-α D α (0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.5, 0 ≤ c ≤ 0.5, 0 < α < 2);Li a Nor b Co c L 1 d G e O2(0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0 ≤ d ≤ 0.5, 0 ≤ e ≤ 0.1);; The a NiG b O2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1); The a CoG b O2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1); The a Mn 1-b G b O2(0.90 ≤ a ≤ 1.8, 0.001 ≤ b ≤ 0.1); The a Mn2G b O4(0.90 ≤ a ≤1.8, 0.001 ≤ b ≤ 0.1); The a Mn 1-g G g PO4(0.90 ≤ a ≤ 1.8, 0 ≤ g ≤ 0.5); The (3-f) Fe2(PO4)3(0 ≤ f ≤ 2); The a FePO4(0.90 ≤ to ≤ 1.8)

[0046] In the above chemical formula, A is Ni, Co, Mn, or a combination thereof; X is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof; D is O, 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; Z is Cr, V, Fe, Sc, Y, or a combination thereof; L 1 is Mn, Al or a combination thereof.

[0047] The cathode active material may include, for example, a lithium nickel-based oxide represented by the following chemical formula 1, a lithium cobalt-based oxide represented by the following chemical formula 2, a lithium iron phosphate-based compound represented by the following chemical formula 3, a cobalt-free lithium nickel-manganese-based oxide represented by the following chemical formula 4, or a combination thereof.

[0048] [Chemical Formula 1]

[0049] Li a1 Ni x1 M 1 y1 M 2 z1 O 2-b1 X b1

[0050] In the above chemical formula 1, 0.9≤a1≤1.8, 0.3≤x1≤1, 0≤y1≤0.7, 0≤z1≤0.7, 0.9≤x1+y1+z1≤1.1, and 0≤b1≤0.1, and M 1 and M 2 are each independently an element selected from Al, B, Ba, Ca, Ce, Co, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Si, Sn, Sr, Ti, V, W, Zr, or a combination thereof, and X is an element selected from F, P, S, or a combination thereof.

[0051] In the above chemical formula 1, 0.6≤x1≤1, 0≤y1≤0.4, and 0≤z1≤0.4, or 0.8≤x1≤1, 0≤y1≤0.2, and 0≤z1≤0.2.

[0052] [Chemical Formula 2]

[0053] Li a2 Co x2 M 3 y2 O 2-b2 X b2

[0054] In the above chemical formula 2, 0.9≤a2≤1.8, 0.7≤x2≤1, 0≤y2≤0.3, 0.9≤x2+y2≤1.1, and 0≤b2≤0.1, and M 3 is an element selected from Al, B, Ba, Ca, Ce, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Se, Si, Sn, Sr, Ti, V, W, Y, Zn, Zr, or a combination thereof, and X is an element selected from F, P, S, or a combination thereof.

[0055] [Chemical Formula 3]

[0056] Li a3 Fe x3 M 4 y3 PO 4-b3 X b3

[0057] In the above chemical formula 3, 0.9≤a3≤1.8, 0.6≤x3≤1, 0≤y3≤0.4, and 0≤b3≤0.1, and M 4 is an element selected from Al, B, Ba, Ca, Ce, Co, Cr, Cu, Mg, Mn, Mo, Ni, Se, Si, Sn, Sr, Ti, V, W, Y, Zn, Zr, or a combination thereof, and X is an element selected from F, P, S, or a combination thereof.

[0058] [Chemical Formula 4]

[0059] Li a4 Ni x4 Mn y4 M 5z4 O 2-b4 X b4

[0060] In the above chemical formula 4, 0.9≤a2≤1.8, 0.8≤x4<1, 0 <y4≤0.2, 0≤z4≤0.2, 0.9≤x4+y4+z4≤1.1, 및 0≤b4≤0.1이고 M 5 is an element selected from Al, B, Ba, Ca, Ce, Cr, Fe, Mg, Mo, Nb, Si, Sn, Sr, Ti, V, W, Zr, or a combination thereof, and X is an element selected from F, P, S, or a combination thereof.

[0061] The average particle diameter (D50) of the positive electrode active material may be 1 μm to 25 μm, for example, 3 μm to 25 μm, 1 μm to 20 μm, 1 μm to 18 μm, 3 μm to 15 μm, or 5 μm to 15 μm. For example, the positive electrode active material may include small particles having an average particle diameter (D50) of 1 μm to 9 μm and large particles having an average particle diameter (D50) of 10 μm to 25 μm. A positive electrode active material having such a particle diameter range can be harmoniously mixed with other components within a positive electrode active material layer and can realize high capacity and high energy density. Here, the average particle diameter may be obtained by selecting 20 or so random particles from a scanning electron microscope image of the positive electrode active material, measuring their particle diameters (diameter, major axis, or major axis length), obtaining a particle size distribution, and then taking the diameter (D50) of particles having a cumulative volume of 50% by volume from the particle size distribution as the average particle diameter.

[0062] The above-mentioned positive electrode active material may be in the form of a secondary particle formed by agglomeration of a plurality of primary particles, or may be in the form of a single particle. In addition, the above-mentioned positive electrode active material may be spherical or nearly spherical in shape, or may be polyhedral or irregular in shape.

[0063] Meanwhile, the positive electrode active material may include a buffer layer on the particle surface. The buffer layer may be expressed as a coating layer, a protective layer, etc., and may play a role in lowering the interfacial resistance between the positive electrode active material and the sulfide-based solid electrolyte particles. For example, the buffer layer may include a lithium-metal-oxide, wherein the metal may be an element selected from, for example, Al, B, Ca, Ce, Cr, Fe, Mg, Mo, Nb, Si, Sn, Sr, Ta, V, W, Zr, or a combination thereof. The lithium-metal-oxide is excellent in lowering the interfacial resistance between the positive electrode active material and the solid electrolyte particles by facilitating the movement of lithium ions and electron conduction, thereby improving the performance of the positive electrode active material.

[0064] The positive electrode active material may be included in an amount of 55 wt% to 95 wt% based on 100 wt% of the positive electrode active material layer, for example, 65 wt% to 94 wt%, or 75 wt% to 91 wt%.

[0065] bookbinder

[0066] The binder serves to adhere the positive electrode active material particles well to each other and also to adhere the positive electrode active material well to the current collector. For example, the binder may include, but is not limited to, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers containing ethylene oxide, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, epoxy resin, (meth)acrylic resin, polyester resin, nylon, etc. As a representative example, the binder may be a fluorine-based binder such as polyvinyl fluoride, polytetrafluoroethylene, or polyvinylidene fluoride.

[0067] The binder may be included in an amount of 0.1 wt% to 5 wt% based on 100 wt% of the positive electrode active material layer, for example, 0.1 wt% to 3 wt%, or 0.5 wt% to 2 wt%.

[0068] solid electrolyte

[0069] The above-described positive electrode active material layer includes a sulfide-based solid electrolyte. For example, the sulfide-based solid electrolyte may include an argyrodite-type sulfide. Alternatively, the positive electrode active material layer may further include a solid electrolyte other than the above-described sulfide-based solid electrolyte. For example, the positive electrode active material layer may further include an oxide-based solid electrolyte, a halide-based solid electrolyte, or a combination thereof. Meanwhile, the following description of the solid electrolyte layer is equally applicable to the above-described sulfide-based solid electrolyte and other solid electrolytes.

[0070] With respect to 100 wt% of the positive electrode active material layer, the solid electrolyte may be included in an amount of 0.1 wt% to 35 wt%, for example, 1 wt% to 35 wt%, 5 wt% to 30 wt%, 8 wt% to 25 wt%, or 10 wt% to 20 wt%.

[0071] In the positive electrode active material layer, the positive electrode active material may be comprised in an amount of 65 to 99 wt% and the solid electrolyte in an amount of 1 to 35 wt%, based on 100 wt% of the total of the positive electrode active material and the solid electrolyte, for example, the positive electrode active material may be comprised in an amount of 80 to 90 wt% and the solid electrolyte in an amount of 10 to 20 wt%. When the solid electrolyte is comprised in the positive electrode in such an amount, the efficiency and life characteristics of the all-solid-state secondary battery can be improved without reducing the capacity.

[0072] Other challenges

[0073] In addition to the aforementioned carbon nanotubes and carbon nanoparticles, the cathode active material layer may optionally further include an additional conductive material. The conductive material is used to impart conductivity to the electrode, and any material that does not cause chemical changes and is electronically conductive in the battery may be used. For example, conductive materials including carbon-based materials such as natural graphite, artificial graphite, carbon fibers, and carbon nanofibers; metallic materials containing copper, nickel, aluminum, silver, etc. in the form of metal powder or metal fibers; conductive polymers such as polyphenylene derivatives; or mixtures thereof may be used.

[0074] The content of the conductive material in the positive electrode active material layer may be 0.01 wt% to 5 wt%, or 0.05 wt% to 3 wt%, 0.08 wt% to 2 wt%, 0.1 wt% to 2 wt%, or 0.2 wt% to 1 wt%, based on 100 wt% of the positive electrode active material layer.

[0075] Aluminum foil can be used as the positive electrode collector, but is not limited thereto.

[0076] Method for manufacturing anode

[0077] In another embodiment, a method for manufacturing a positive electrode is provided, including dry mixing a positive electrode active material, a sulfide-based solid electrolyte, and carbon nanoparticles, adding a binder and carbon nanotubes to the resultant of the dry mixing, and mixing the mixture to obtain a positive electrode active material slurry, wherein the carbon nanotubes are added in an amount of 40 wt% to 90 wt% and the carbon nanoparticles are added in an amount of 10 wt% to 60 wt% based on 100 wt% of the total of the carbon nanotubes and carbon nanoparticles. The above description relates to a method for manufacturing a positive electrode which is an embodiment, and below, descriptions overlapping with the above will be omitted, and a detailed description will be given of a manufacturing process of a positive electrode which is an embodiment.

[0078] According to one embodiment, the dry mixing can be performed by adding carbon nanoparticles in powder form to the dry mixture of the positive electrode active material and the sulfide-based solid electrolyte.

[0079] The introduction of the above binder and carbon nanotubes may be by introducing a mixed solution containing the binder and carbon nanotubes into the obtained product of the dry mixing, and the low polarity solvent described above in the positive electrode may be used as the solvent of the mixed solution.

[0080] Alternatively, the binder and carbon nanotubes may be introduced by mixing a binder solution containing a binder and a first low-polarity solvent and a carbon nanotube solution containing carbon nanotubes and a second low-polarity solvent into the obtained product of the dry mixing.

[0081] Alternatively, the binder solution may be added first to the obtained product of the dry mixing and mixed, and then the carbon nanotube solution may be added and mixed.

[0082] The first low-polarity solvent and the second low-polarity solvent may be, for example, low-polarity solvents having a polarity of 0.074 to 0.281, and the above-described description for the positive electrode may be equally applied to the low-polarity solvent.

[0083] The first low-polarity solvent and the second low-polarity solvent may be the same or different from each other.

[0084] Next, the positive electrode active material slurry can be applied onto the positive electrode current collector described above. At this time, any method commonly known in the art can be used without limitation as a method for applying the material. For example, coating can be performed using a coating device (bar coater, comma coater, shutter coater, slot die coater, gravure coater, spray coater, etc.). The same content described above for the positive electrode can be applied to the positive electrode current collector.

[0085] After applying the above positive electrode active material slurry, the applied positive electrode active material slurry may be dried and rolled to form a positive electrode active material layer on the positive electrode current collector. Here, the conditions for drying and rolling may be as commonly known in the art.

[0086] All-solid-state secondary battery

[0087] In another embodiment, an all-solid-state secondary battery is provided, which includes the above-described positive electrode; a negative electrode; and a solid electrolyte layer positioned between the positive electrode and the negative electrode. Since the all-solid-state secondary battery includes the positive electrode according to the above-described embodiment, it can secure a balance between electronic and ionic conduction, thereby reducing the resistance of the electrode plate and improving cell performance, and effectively securing structural stability.

[0088] Hereinafter, descriptions overlapping with the above will be omitted, and components of an all-solid-state secondary battery, which is an example of an implementation, will be described in more detail with reference to FIGS. 1 and 2.

[0089] The above all-solid-state secondary battery may also be expressed as an all-solid-state battery or an all-solid-state lithium secondary battery.

[0090] FIG. 1 is a cross-sectional view of an all-solid-state secondary battery according to an embodiment. Referring to FIG. 1, the all-solid-state secondary battery (100) may have a structure in which an electrode assembly in which 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) are laminated is housed in a battery case. The all-solid-state secondary battery (100) may further include an elastic layer (500) on the outer side of at least one of the positive electrode (200) and the negative electrode (400). Although FIG. 1 illustrates one electrode assembly including the negative electrode (400), the solid electrolyte layer (300), and the positive electrode (200), an all-solid-state secondary battery may be manufactured by laminating two or more electrode assemblies.

[0091] cathode

[0092] An anode for an all-solid-state secondary battery includes a cathode current collector and a cathode active material layer positioned on the cathode current collector. The cathode active material layer includes a cathode active material and may further include a binder, a conductive material, and / or a conductive material.

[0093] The above negative active material may include a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, an alloy of lithium metal, a material capable of doping and dedoping lithium, or a transition metal oxide.

[0094] The material capable of reversibly intercalating / deintercalating the lithium ions may include a carbon-based negative electrode active material, for example, crystalline carbon, amorphous carbon, or a combination thereof. Examples of the crystalline carbon include graphite such as natural graphite or artificial graphite in an amorphous, plate-like, flake-like, spherical, or fibrous form, and examples of the amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, calcined coke, and the like.

[0095] As the above lithium metal alloy, an alloy of lithium and a metal selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn can be used.

[0096] As the material capable of doping and dedoping the lithium, a Si-based negative electrode active material or a Sn-based negative electrode active material can be used. The Si-based negative electrode active material may include silicon, a silicon-carbon composite, SiO x(0 <x<2), Si-Q 합금(상기 Q는 알칼리 금속, 알칼리 토금속, 13족 원소, 14족 원소, 15족 원소, 16족 원소, 전이금속, 희토류 원소, 또는 이들의 조합에서 선택되는 원소이며, Si은 아님), 또는 이들의 조합 등을 사용할 수 있다. 상기 Sn계 음극 활물질로는 Sn, SnO2, Sn-R 합금(상기 R은 알칼리 금속, 알칼리 토금속, 13족 원소, 14족 원소, 15족 원소, 16족 원소, 전이금속, 희토류 원소, 또는 이들의 조합에서 선택되는 원소이며, Sn은 아님), 또는 이들의 조합 등을 사용할 수 있고, 혹은 이들 중 적어도 하나와 SiO2를 혼합하여 사용할 수도 있다. 상기 원소 Q 및 R로는 Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Tl, Ge, P, As, Sb, Bi, S, Se, Te, Po, 또는 이들의 조합에서 선택되는 것을 사용할 수 있다.

[0097] The silicon-carbon composite may be a composite of silicon and amorphous carbon. According to one embodiment, the silicon-carbon composite may be in the form of silicon particles and amorphous carbon coated on the surface of the silicon particles. For example, the composite may include secondary particles (cores) in which silicon primary particles are assembled and an amorphous carbon coating layer (shell) positioned on the surface of the secondary particles. The amorphous carbon may also be positioned between the silicon primary particles, such that, for example, the silicon primary particles may be coated with amorphous carbon. The secondary particles may be dispersed and present in an amorphous carbon matrix.

[0098] Alternatively, the silicon-carbon composite may further comprise crystalline carbon. For example, the silicon-carbon composite may comprise a core comprising crystalline carbon and silicon particles and an amorphous carbon coating layer positioned on the surface of the core.

[0099] The above Si-based negative electrode active material or Sn-based negative electrode active material can be used in a mixture with a carbon-based negative electrode active material.

[0100] The content of the negative active material in the above negative active material layer may be 95 wt% to 99 wt% with respect to the total weight of the negative active material layer.

[0101] In one embodiment, the negative electrode active material layer may further include a binder and optionally further include a conductive material. The content of the binder in the negative electrode active material layer may be 1 wt% to 5 wt% based on the total weight of the negative electrode active material layer. In addition, when the negative electrode active material layer further includes a conductive material, the negative electrode active material layer may include 90 wt% to 98 wt% of the negative electrode active material, 1 wt% to 5 wt% of the binder, and 1 wt% to 5 wt% of the conductive material.

[0102] The above binder serves to adhere the negative electrode active material particles well to each other and also to adhere the negative electrode active material well to the current collector. The binder may be a non-aqueous binder, an aqueous binder, a dry binder, or a combination thereof.

[0103] Examples of the non-aqueous binder include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamideimide, polyimide, or combinations thereof.

[0104] The above-mentioned aqueous binder may be selected from styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluoroelastomer, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenol resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0105] When using an aqueous binder as the negative electrode binder, a thickener capable of imparting viscosity may be used together, and the thickener may include, for example, a cellulose-based compound. The cellulose-based compound may be a mixture of one or more of carboxymethyl cellulose, hydroxypropylmethyl cellulose, methyl cellulose, or an alkali metal salt thereof. The alkali metal may be Na, K, or Li. The amount of the thickener may be 0.1 to 3 parts by weight based on 100 parts by weight of the negative electrode active material.

[0106] The above dry binder is a polymeric material capable of being fiberized, and may be, for example, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or a combination thereof.

[0107] The conductive material is used to provide conductivity to the electrode, and any material that does not cause chemical changes and is electronically conductive can be used in the battery. Specific examples include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fibers, carbon nanofibers, and carbon nanotubes; metal-based materials in the form of metal powder or metal fibers, including copper, nickel, aluminum, and silver; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0108] The negative electrode current collector may be selected from copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and a combination thereof.

[0109] As another example, the negative electrode for an all-solid-state secondary battery may be a precipitation-type negative electrode. The precipitation-type negative electrode may refer to a negative electrode that does not contain a negative electrode active material when the battery is assembled, but in which lithium metal or the like is precipitated or deposited on the negative electrode when the battery is charged, thereby acting as a negative electrode active material.

[0110] Fig. 2 is a schematic cross-sectional view of an all-solid-state secondary battery including a precipitation-type negative electrode. Referring to Fig. 2, the precipitation-type negative electrode (400') may include a negative electrode current collector (401) and a negative electrode coating layer (405) positioned on the negative electrode current collector. An all-solid-state secondary battery including such a precipitation-type negative electrode (400') starts initial charging in a state in which no negative electrode active material is present, and during charging, high-density lithium metal is precipitated or deposited between the negative electrode current collector (401) and the negative electrode coating layer (405) or on the negative electrode coating layer (405) to form a lithium metal layer (404), which may function as a negative electrode active material. Accordingly, in an all-solid-state secondary battery that has been charged more than once, the precipitation-type negative electrode (400') may include, for example, a negative electrode current collector (401), a lithium metal layer (404) positioned on the negative electrode current collector, and a negative electrode coating layer (405) positioned on the metal layer. The lithium metal layer (404) refers to a layer in which lithium metal or the like is precipitated during the charging process of the battery, and may be referred to as a metal layer, a lithium layer, a lithium deposition layer, or a negative electrode active material layer.

[0111] The above cathode coating layer (405) may be referred to as a lithium electrodeposition induction layer or a cathode catalyst layer, and may include a metal, a carbon material, or a combination thereof.

[0112] The metal may be a lithium-philic metal, and may include, for example, gold, platinum, palladium, silicon, silver, aluminum, bismuth, tin, zinc, or a combination thereof, and may be composed of one type of these or may be composed of several types of alloys. When the metal is present in the form of particles, the average particle diameter (D50) thereof may be about 4 μm or less, and may be, for example, 10 nm to 4 μm.

[0113] The carbon material may be, for example, crystalline carbon, amorphous carbon, or a combination thereof. The crystalline carbon may be, for example, natural graphite, artificial graphite, mesophase carbon microbeads, or a combination thereof. The amorphous carbon may be, for example, carbon black, activated carbon, acetylene black, Denka black, Ketjen black, or a combination thereof. For example, the carbon material may refer to amorphous carbon.

[0114] When the cathode coating layer (405) includes both the metal and the carbon material, the mixing ratio of the metal and the carbon material may be, for example, a weight ratio of 1:10 to 2:1. In this case, the precipitation of lithium metal can be effectively promoted and the characteristics of the all-solid-state secondary battery can be improved. The cathode coating layer (405) may include, for example, a carbon material supported with a catalytic metal, or may include a mixture of metal particles and carbon material particles.

[0115] The cathode coating layer (405) may include, for example, the above-described lithium-philic metal and amorphous carbon, in which case the precipitation of the lithium metal can be effectively promoted. As a specific example, the cathode coating layer (405) may include a composite in which a lithium-philic metal is supported on amorphous carbon.

[0116] The cathode coating layer (405) may further include a binder, which may be, for example, a conductive binder. In addition, the cathode coating layer (405) may further include general additives such as fillers, dispersants, and ionic conductive agents.

[0117] The thickness of the cathode coating layer (405) may be, for example, 100 nm to 20 μm, or 500 nm to 10 μm, or 1 μm to 5 μm.

[0118] The precipitation-type negative electrode (400') may further include, for example, a thin film on the surface of the negative electrode current collector, that is, between the negative electrode current collector and the negative electrode coating layer. The thin film may include an element capable of forming an alloy with lithium. The element capable of forming an alloy with lithium may be, for example, gold, silver, zinc, tin, indium, silicon, aluminum, bismuth, etc., and may be composed of one type thereof or may be composed of multiple types of alloys. The thin film may further flatten the precipitation form of the lithium metal layer (404) and further improve the characteristics of the all-solid-state secondary battery. The thin film may be formed by, for example, a vacuum deposition method, a sputtering method, a plating method, etc. The thickness of the thin film may be, for example, 1 nm to 500 nm.

[0119] The lithium metal layer (404) may include lithium metal or a lithium alloy. The lithium alloy may be, for example, a Li-Al alloy, a Li-Sn alloy, a Li-In alloy, a Li-Ag alloy, a Li-Au alloy, a Li-Zn alloy, a Li-Ge alloy, or a Li-Si alloy.

[0120] The thickness of the lithium metal layer (404) may be 1 µm to 500 µm, 1 µm to 200 µm, 1 µm to 100 µm, or 1 µm to 50 µm. If the thickness of the lithium metal layer (404) is too thin, it may be difficult to perform the role of a lithium storage, and if it is too thick, the battery volume may increase and performance may deteriorate.

[0121] When such a precipitation-type cathode is applied, the cathode coating layer (405) can play a role in protecting the lithium metal layer (404) and suppressing the precipitation growth of lithium deadlight. Accordingly, short-circuiting and capacity reduction of the all-solid-state battery can be suppressed, and the life characteristics can be improved.

[0122] solid electrolyte layer

[0123] The solid electrolyte layer includes a solid electrolyte. The solid electrolyte may be a type of inorganic solid electrolyte, and may include, for example, a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a halide-based solid electrolyte, or a combination thereof. According to one embodiment, the solid electrolyte layer may include a sulfide-based solid electrolyte.

[0124] Sulfide-based solid electrolyte

[0125] Sulfide-based solid electrolytes include, for example, Li2S-P2S5, Li2S-P2S5-LiX (where X is a halogen element, for example, 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, Li2S-P2S5-Z. m S n (m, n are integers, Z is Ge, Zn or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q (p, q are integers, and M is P, Si, Ge, B, Al, Ga or In), or a combination thereof.

[0126] A sulfide-based solid electrolyte can be obtained, for example, by mixing Li2S and P2S5 in a molar ratio of 50:50 to 90:10, or 50:50 to 80:20, and optionally heat-treating them. Within the above mixing ratio range, a sulfide-based solid electrolyte having excellent ionic conductivity can be produced. The ionic conductivity can be further improved by further including other components such as SiS2, GeS2, and B2S3.

[0127] Methods for mixing sulfur-containing raw materials for producing sulfide-based solid electrolytes include mechanical milling or the solution method. Mechanical milling involves placing raw materials in a ball mill reactor and vigorously stirring them to finely atomize and mix them. Using the solution method, the raw materials are mixed in a solvent to obtain a solid electrolyte as a precipitate. Furthermore, heat treatment after mixing can solidify the crystals of the solid electrolyte and improve ionic conductivity. For example, a sulfide-based solid electrolyte can be produced by mixing sulfur-containing raw materials and heat-treating them twice or more, resulting in a sulfide-based solid electrolyte with high ionic conductivity and robustness.

[0128] According to one embodiment, a sulfide-based solid electrolyte can be manufactured through, for example, a first heat treatment in which sulfur-containing raw materials are mixed and calcined at 120°C to 350°C, and a second heat treatment in which the first heat treatment result is mixed and calcined at 350°C to 800°C. The first heat treatment and the second heat treatment can each be performed in an inert gas or nitrogen atmosphere. The first heat treatment can be performed for 1 to 10 hours, and the second heat treatment can be performed for 5 to 20 hours. The first heat treatment can have the effect of milling small raw materials, and the second heat treatment can synthesize the final solid electrolyte. Through two or more such heat treatments, a high-performance sulfide-based solid electrolyte with high ionic conductivity and robustness can be obtained, and such a solid electrolyte can be said to be suitable for mass production. The temperature of the first heat treatment may be, for example, 150°C to 330°C, or 200°C to 300°C, and the temperature of the second heat treatment may be, for example, 380°C to 700°C, or 400°C to 600°C.

[0129] For example, the sulfide-based solid electrolyte may include an argyrodite-type sulfide. The argyrodite-type sulfide-based solid electrolyte has an ionic conductivity of 10, which is the ionic conductivity of a typical liquid electrolyte at room temperature. -4 10 inland -2 It has a high ionic conductivity approaching the S / cm range, can form a close bond between a positive electrode active material and a solid electrolyte without causing a decrease in ionic conductivity, and further can form a close interface between an electrode layer and a solid electrolyte layer. An all-solid-state secondary battery including this can have improved battery performance, such as rate characteristics, Coulombic efficiency, and cycle life characteristics.

[0130] The argyrodite-type sulfide-based solid electrolyte may include, for example, a compound represented by the chemical formula 11 below.

[0131] [Chemical Formula 11]

[0132] (Li a M 1 b M 2 c )(P d M 3 e )(S f M 4 g )X h

[0133] In the above chemical formula 11, 4≤a≤8, and M 1 is Mg, Cu, Ag, or a combination thereof, and 0≤b<0.5, and M 2 is Na, K, or a combination thereof, 0≤c<0.5, and M 3 is Sn, Zn, Si, Sb, Ge, or a combination thereof, and 0 <d<4, 0≤e<1 이고, M 4 is O, SO n , or a combination thereof, and 1.5≤n≤5, 3≤f≤12, 0≤g<2, and X is F, Cl, Br, I, or a combination thereof, and 0≤h≤2.

[0134] For example, in chemical formula 11, a halide element (X) may be included as an essential element, in which case 0 <h≤2로 표시될 수 있다. 일 예로 화학식 11에 M 1 Elements may be required, in which case 0 <b<0.5로 표시될 수 있다. 화학식 11에서 M 3 can be understood as an element substituted in place of P and 0 <e<1일 수 있다. 화학식 11에서 M 4 is substituted in the S position, for example, 0 <g<2일 수 있으며 S의 비율인 f는 예를 들어 3≤f≤7일 수 있다. M 4 Go SO n If SO n It can be, for example, S4O6, S3O6, S2O3, S2O4, S2O5, S2O6, S2O7, S2O8, SO4, or SO5, and can be, for example, SO4.

[0135] For example, in chemical formula 11, a+b+c+h=7, d+e=1, and f+g+h=6.

[0136] As a specific example, argyrodite-type sulfide-based solid electrolyte particles include Li3PS4 and Li7P3S. 11 , Li7PS6, Li6PS5Cl, Li6PS5Br, Li 5.8 PS 4.8 Cl 1.2 , Li 6.2 PS 5.2 Br 0.8 , Li 5.75 PS 4.75 Cl 1.25 , (Li 5.69 Cu 0.06 )PS 4.75 Cl 1.25 , (Li 5.72 Cu 0.03 )PS 4.75 Cl 1.25 , (Li 5.69 Cu 0.06 )P(S 4.70 (SO4) 0.05 )Cl 1.25 , (Li 5.69 Cu 0.06 )P(S4.60 (SO4) 0.15 )Cl 1.25 , (Li 5.72 Cu 0.03 )P(S 4.725 (SO4) 0.025 )Cl 1.25 , (Li 5.72 Na 0.03 )P(S 4.725 (SO4) 0.025 )Cl 1.25 , Li 5.75 P(S 4.725 (SO4) 0.025 )Cl 1.25 , or combinations thereof, but are not limited thereto.

[0137] An argyrodite-type sulfide-based solid electrolyte can be manufactured, for example, by mixing lithium sulfide and phosphorus sulfide, and optionally, lithium halide. After mixing these, a heat treatment may be performed. The heat treatment may include, for example, two or more heat treatment steps. Here, manufacturing an argyrodite-type sulfide-based solid electrolyte may include, for example, a first heat treatment of mixing raw materials and calcining at 120°C to 350°C, and a second heat treatment of mixing the resultant of the first heat treatment again and calcining at 350°C to 800°C.

[0138] The sulfide-based solid electrolyte may be in the form of particles, and the average particle diameter (D50) of the particles may be, for example, 0.1 ㎛ to 5.0 ㎛ or 0.1 ㎛ to 3.0 ㎛, and may be small particles of 0.1 ㎛ to 1.9 ㎛ or large particles of 2.0 ㎛ to 5.0 ㎛. The sulfide-based solid electrolyte particles may be a mixture of small particles having an average particle diameter of 0.1 ㎛ to 1.9 ㎛ and large particles having an average particle diameter of 2.0 ㎛ to 5.0 ㎛. The average particle diameter of the sulfide-based solid electrolyte particles may be measured from an electron microscope image, and for example, a particle size distribution may be obtained by measuring the size (diameter or major axis length) of about 20 particles in a scanning electron microscope image, and D50 may be calculated from this.

[0139] Oxide-based solid electrolyte

[0140] Oxide-based 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 P3-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-GeO2계 세라믹스, 가넷(Garnet)계 세라믹스 Li 3+x La3M2O 12 (M= Te, Nb, or Zr; x is an integer from 1 to 10), or mixtures thereof.

[0141] Halide-based solid electrolyte

[0142] The solid electrolyte layer may further include, for example, a halide-based solid electrolyte. The halide-based solid electrolyte contains a halogen element as a main component, and may mean that the ratio of the halide element to all elements constituting the solid electrolyte is 50 mol% or more, 70 mol% or more, 90 mol% or more, or 100 mol%. For example, the halide-based solid electrolyte may not contain a sulfur element.

[0143] The halide-based solid electrolyte may contain lithium element, a metal element other than lithium, and a halogen element. The metal element other than lithium may be Al, As, B, Bi, Ca, Cd, Co, Cr, Fe, Ga, Hf, In, Mg, Mn, Ni, Sb, Sc, Sn, Ta, Ti, Y, Zn, Zr, or a combination thereof. The halogen element may be F, Cl, Br, I, or a combination thereof, and may be Cl, Br, or a combination thereof. The halide-based solid electrolyte may contain, for example, Li aM1X6 (M is Al, As, B, Bi, Ca, Cd, Co, Cr, Fe, Ga, Hf, In, Mg, Mn, Ni, Sb, Sc, Sn, Ta, Ti, Y, Zn, Zr, or a combination thereof, X is F, Cl, Br, I, or a combination thereof, and 2≤a≤3) can be represented. The halide-based solid electrolyte may be, for example, Li2ZrCl6, Li 2.7 Y 0.7 Zr 0.3 Cl6, Li 2.5 Y 0.5 Zr 0.5 Cl6, Li 2.5 In 0.5 Zr 0.5 Cl6, Li2In 0.5 Zr 0.5 Cl6, Li3YBr6, Li3YCl6, Li3YBr2Cl4, Li3YbCl6, Li 2.6 Hf 0.4 Yb 0.6 Cl6, or combinations thereof, but is not limited thereto.

[0144] bookbinder

[0145] The solid electrolyte layer may further include a binder. Binders include, for example, nitrile-butadiene rubber, hydrogenated nitrile-butadiene rubber, styrene-butadiene rubber, acrylated styrene-butadiene rubber, acrylonitrile-butadiene rubber, acrylic rubber, butyl rubber, fluoroelastomer, natural rubber, polydimethylsiloxane, polyethylene oxide, polyvinylpyrrolidone, polyvinylpyridine, chlorosulfonated polyethylene, polyvinyl alcohol, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-propylene-diene copolymer, polyamideimide, polyimide, poly(meth)acrylate, polyacrylonitrile, polystyrene, polyurethane, and the like. copolymers, or combinations thereof.

[0146] The binder may be included in an amount of 0.1 wt% to 3 wt% based on 100 wt% of the solid electrolyte layer, for example, 0.5 wt% to 2 wt%, or 0.5 wt% to 1.5 wt%. When the binder is included in the above range, the components within the solid electrolyte layer can be well combined without lowering the ionic conductivity of the solid electrolyte, thereby improving the durability and reliability of the battery.

[0147] Other ingredients

[0148] The solid electrolyte layer may optionally further comprise an alkali metal salt, and / or an ionic liquid, and / or a conductive polymer.

[0149] The above alkali metal salt may be, for example, a lithium salt. The content of the lithium salt in the solid electrolyte layer may be 1 M or more, for example, 1 M to 4 M. In this case, the lithium salt may improve ion conductivity by enhancing the lithium ion mobility of the solid electrolyte layer.

[0150] The lithium salt may be applied without limitation on type, and may include, for example, LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiAlO2, LiAlCl4, LiPO2F2, LiCl, LiI, LiSCN, LiN(CN)2, lithium bis(oxalato)borate (LiBOB), lithium difluoro(oxalato)borate (LiDFOB), lithium difluorobis(oxalato)phosphate (LiDFBP), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(pentafluoroethanesulfonyl)imide (LiBETI), lithium trifluoromethanesulfonate, lithium tetrafluoroethanesulfonate, or a combination thereof.

[0151] For example, the lithium salt may be an imide-based lithium salt such as LiTFSI, LiFSI, LiBETI, or a combination thereof. The imide-based lithium salt can maintain or improve ionic conductivity by appropriately maintaining chemical reactivity with the ionic liquid.

[0152] Ionic liquids are salts or molten salts that are composed only of ions and are liquid at room temperature, with a melting point below room temperature.

[0153] The ionic liquid comprises a) one or more cations selected from ammonium, pyrrolidinium, pyridinium, pyrimidinium, imidazolium, piperidinium, pyrazolium, oxazolium, pyridazinium, phosphonium, sulfonium, trizolium, 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 be a compound containing one or more anions selected from among.

[0154] The ionic liquid may be selected from, for example, N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide, N-butyl-N-methylpyrrolidinium bis(3-trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide, or a combination thereof.

[0155] 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 maintain or improve ionic conductivity by improving the electrochemical contact area with the electrode. Accordingly, the energy density, discharge capacity, rate characteristics, etc. of the all-solid-state secondary battery can be improved.

[0156] The above-mentioned all-solid-state secondary battery may be a unit cell having a structure of positive electrode / solid electrolyte layer / negative electrode, a bi-cell having a structure of negative electrode / solid electrolyte layer / positive electrode / solid electrolyte layer / negative electrode, or a laminated battery in which the structure of the unit cell is repeated.

[0157] The shape of the above-mentioned all-solid-state secondary battery is not particularly limited, and may be, for example, coin-shaped, button-shaped, sheet-shaped, stacked, cylindrical, flat, etc. In addition, the above-mentioned all-solid-state secondary battery can be applied to large-scale batteries used in electric vehicles, etc. For example, the above-mentioned all-solid-state secondary battery can be used in hybrid vehicles such as plug-in hybrid electric vehicles (PHEVs). In addition, it can be used in fields requiring a large amount of power storage, and for example, it can be used in electric bicycles or power tools, etc. In addition, the above-mentioned all-solid-state secondary battery can be used in various fields such as portable electronic devices.

[0158] Hereinafter, examples and comparative examples of the present invention are described. The following examples are merely examples of the present invention, and the present invention is not limited to the following examples.

[0159] Example 1

[0160] 1. Manufacturing of the anode

[0161] LiNi coated with Li2O-ZrO2 0.8 Co 0.15 Mn 0.05 O2 positive electrode active material and lithium argyrodite type solid electrolyte Li6PS5Cl (D50=3㎛) and carbon black in powder form with an average particle diameter (D50) of 50 nm were dry mixed in a dry atmosphere at a temperature of 25°C and a dew point of -40°C to -45°C.

[0162] Next, a binder solution containing a polyvinylidene fluoride binder mixed in a 2-ethylhexyl acetate solvent and a carbon nanotube solution containing a 2-ethylhexyl acetate solvent and L-carbon nanotubes (SWCNT) were prepared. The binder solution was added to the product obtained through the dry mixing and mixed. At this time, excluding the solvent content, the positive electrode active material was 84 wt%, Li6PS5Cl 15 wt%, carbon black 0.3 wt%, and binder 1 wt%. The carbon nanotube solution was added to the mixture containing the binder solution and mixed, thereby preparing a positive electrode active material slurry. At this time, the carbon nanotubes were adjusted to be 75 wt% and the carbon black to be 25 wt% based on 100 wt% of the total of the carbon nanotubes and carbon nanoparticles (carbon black).

[0163] Afterwards, an aluminum foil having a thickness of 12 ㎛ was used as a positive electrode current collector, and the positive electrode active material slurry was applied on one surface of the positive electrode current collector using a bar coater at 22 mg / cm 2 After applying the coating, it was dried in a convection oven at 80°C for 10 minutes, and then rolled to produce a positive electrode.

[0164] 2. Manufacturing of solid electrolyte layer

[0165] A solid electrolyte layer composition is prepared by adding an argyrodite-type solid electrolyte Li6PS5Cl (D50=3㎛) to a binder solution in which an acrylic binder (SX-A334, Zeon) is dissolved in an isobutylyl isobutylate (IBIB) solvent and stirring the solution. The composition contains 98.5 wt% of the solid electrolyte and 1.5 wt% of the binder. The composition is applied onto a release PET film using a bar coater and dried at room temperature to prepare a solid electrolyte layer.

[0166] 3. Manufacturing of the cathode

[0167] An Ag / C composite is prepared by mixing carbon black having a primary particle size (D50) of about 30 nm and silver (Ag) having an average particle size (D50) of about 60 nm in a weight ratio of 3:1, and 0.25 g of the composite is added to 2 g of an NMP solution containing 7 wt% of polyvinylidene fluoride binder and mixed to prepare a negative electrode coating layer composition. This is applied to a nickel foil current collector using a bar coater and vacuum-dried to prepare a deposition-type negative electrode in which a negative electrode coating layer is formed on the current collector.

[0168] 4. Manufacturing of all-solid-state secondary batteries

[0169] The prepared positive electrode, negative electrode, and solid electrolyte layer are cut, a solid electrolyte layer is laminated on the positive electrode, and then the negative electrode is laminated on top of that. This is sealed in a pouch shape and subjected to a warm isostatic press (WIP) at 85°C and 500 MPa for 30 minutes to manufacture an all-solid-state secondary battery.

[0170] Example 2

[0171] A positive electrode and an all-solid-state secondary battery were manufactured in substantially the same manner as Example 1, except that the carbon nanotubes were 50 wt% and the carbon black was 50 wt%, based on 100 wt% of the total of the carbon nanotubes and carbon nanoparticles.

[0172] Comparative Example 1

[0173] Without using carbon nanoparticles, LiNi 0.8 Co 0.15 Mn 0.05 A cathode and an all-solid-state secondary battery were manufactured in substantially the same manner as in Example 1, except that a cathode active material slurry was used, which was mixed to have 85 wt% of O2 cathode active material, 13 wt% of lithium argyrodite-type solid electrolyte Li6PS5Cl, 1 wt% of polyvinylidene fluoride binder, and 1 wt% of carbon nanotubes.

[0174] Comparative Example 2

[0175] A positive electrode and an all-solid-state secondary battery were manufactured in substantially the same manner as Example 1, except that the carbon nanotubes were 25 wt% and the carbon black was 75 wt%, based on 100 wt% of the total of the carbon nanotubes and carbon nanoparticles.

[0176] Comparative Example 3

[0177] A positive electrode and an all-solid-state secondary battery were manufactured in substantially the same manner as Example 1, except that the carbon nanotubes were 95 wt% and the carbon black was 5 wt%, based on 100 wt% of the total of the carbon nanotubes and carbon nanoparticles.

[0178] Evaluation Example 1: SEM Analysis

[0179] In order to observe the positive electrode active material layer manufactured in Comparative Example 1, a cross-sectional specimen was manufactured, and an image taken with a scanning electron microscope (SEM) at 10,000x magnification is shown in Fig. 6.

[0180] Referring to Fig. 6, in the case of Comparative Example 1, which used only carbon nanotubes as a conductive material without using carbon nanoparticles, it can be confirmed that the carbon nanotubes (11) in the positive electrode active material layer are aggregated and exist unevenly.

[0181] Evaluation Example 2: Solvent Residue Evaluation

[0182] The positive electrode active material layers manufactured in Examples 1 and 2 were each collected and analyzed by gas chromatography to measure the residual amount (ppm) of 2-ethylhexyl acetate, a solvent, in the positive electrode active material layers, which is shown in Table 1 below.

[0183] Example 1 Example 2 Residual amount of solvent (ppm) 352353

[0184] Referring to Table 1 above, it can be confirmed that the positive electrode active materials manufactured in Examples 1 and 2 contain 500 ppm or less of the low-polarity solvent with respect to 100 wt% of the positive electrode active material layer.

[0185] Evaluation Example 3: Viscosity Evaluation

[0186] In order to confirm the change in viscosity of the slurry according to the change in the content of carbon nanoparticles, the viscosity change according to the shear rate (1 / s) of the positive electrode active material slurries obtained from Comparative Examples 1 and 2 and Examples 1 and 2 is shown in Fig. 7. In addition, an enlarged view of the squared portion of Fig. 7 is shown in Fig. 8. In addition, the viscosity values ​​for Comparative Examples 1 and 2 and Examples 1 and 2 when the shear rates are 0.1 (1 / s), 1 (1 / s) and 10 (1 / s) are shown in Table 2 below. Here, the viscosity was measured by specifying the shear rate range of 0.01 to 1000 using a rheometer viscometer at a temperature of 25°C under a dew point condition of -45°C with moisture management.

[0187] Shear rate comparison example 1 Example 1 Example 2 Comparative example 20.145,25942,75134,37916,658110,84215,12998139748101468157011391188

[0188] Referring to the results in FIG. 7, FIG. 8 and Table 2, it can be confirmed that in the case of Examples 1 and 2, compared to Comparative Example 1 in which carbon nanoparticles were not added, the area of ​​the hysteresis loop was reduced through mixing carbon nanotubes and carbon nanoparticles, thereby improving the dispersibility of the slurry.

[0189] Evaluation Example 4: Evaluation of Conductivity and Structural Stability

[0190] The results of measuring the electronic conductivity (σ_el) and ionic conductivity (σ_ion) of the positive electrode plates measured through electrochemical impedance spectroscopy (EIS) using the positive electrodes obtained from Comparative Examples 1 to 3 and Examples 1 and 2 are shown in Fig. 9. Here, EIS was measured by punching out the positive electrode cross-section plates to 10 pi, assembling them into a torque cell, and then setting the temperature to 45°C in a constant temperature chamber.

[0191] Referring to Figure 9, it can be confirmed that in the case of Examples 1 and 2, as the content of carbon nanoparticles used together with carbon nanotubes increases, both electronic conductivity and ionic conductivity increase compared to Comparative Examples 1 and 3.

[0192] However, in the case of Comparative Example 2, the content of carbon nanoparticles used together with carbon nanotubes was high, so electronic conductivity and ionic conductivity were excellent, but it was confirmed that there was a problem with structural stability due to a detachment phenomenon occurring between the aluminum substrate (foil) as the positive electrode current collector and the positive electrode active material layer.

[0193] Evaluation Example 5: Charge / Discharge Characteristics Evaluation

[0194] In order to evaluate the discharge capacity and average discharge voltage of the all-solid-state secondary batteries manufactured in Comparative Example 1 and Example 2, the batteries were charged at a constant current of 0.1 C until the battery voltage became 4.25 V in a constant temperature chamber at 45°C, and discharged at a constant current of 0.1 C until the battery voltage became 2.5 V (first cycle); charged at a constant current of 0.1 C until the battery voltage became 4.25 V, and discharged at a constant current of 0.33 C until the battery voltage became 2.5 V (second cycle); charged at a constant current of 0.1 C until the battery voltage became 4.25 V, and discharged at a constant current of 1.0 C until the battery voltage became 2.5 V (third cycle).

[0195] The changes in discharge capacity for the all-solid-state secondary batteries manufactured in Comparative Example 1 and Examples 1 and 2 are shown in Fig. 10 and Table 3 below.

[0196] In addition, the measurement results of the average discharge voltage for the all-solid-state secondary batteries manufactured in Comparative Example 1 and Examples 1 and 2 are shown in Fig. 11 and Table 4 below.

[0197] Discharge capacity (mAh / g) 0.1 C 0.33 C 1.0 C Comparative example 1210.1 197.2 182.8 Example 1210.2 197.4 183.1 Example 2210.4 197.5 183.4

[0198] Average discharge voltage (V) 0.1 C 0.33 C 1.0 C Comparative example 13.82 13.77 6 3.61 4 Example 13.82 2 3.77 8 3.62 2 Example 23.82 4 3.78 5 3.64 1

[0199] Referring to the evaluation results of Fig. 10, Fig. 11, Table 3 and Table 4, in the case of Examples 1 and 2 in which carbon nanoparticles were mixed and used, it was confirmed that the discharge capacity and average discharge voltage increased in 3 charge / discharge cycles compared to Comparative Example 1.

[0200] Although the preferred embodiments have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concepts defined in the following claims also fall within the scope of the present invention.

[0201] [Explanation of symbols]

[0202] 1: Cathode active material 2: Sulfide-based solid electrolyte

[0203] 11: Carbon nanotubes 12: Carbon nanoparticles

[0204] 100: All-solid-state battery 200: Cathode

[0205] 201: Cathode current collector 203: Cathode active material layer

[0206] 300: solid electrolyte layer 400: cathode

[0207] 401: Negative current collector 403: Negative active material layer

[0208] 400': Precipitation type cathode 404: Lithium metal layer

[0209] 405: Cathode coating layer 500: Elastic layer

Claims

1. A positive electrode current collector; and a positive electrode active material layer positioned on the positive electrode current collector; The above cathode active material layer includes a cathode active material, a sulfide-based solid electrolyte, a binder, and a conductive material. The above challenge material comprises carbon nanotubes and carbon nanoparticles, An anode, wherein the carbon nanotubes are included in an amount of 40 to 90 wt%, and the carbon nanoparticles are included in an amount of 10 to 60 wt%, based on 100 wt% of the total of the carbon nanotubes and carbon nanoparticles.

2. In paragraph 1, The above carbon nanotube is a single-walled carbon nanotube, a double-walled carbon nanotube, a multi-walled carbon nanotube, or a combination thereof.

3. In paragraph 1, The above carbon nanoparticles are anodes of carbon black, acetylene black, Ketjen black, Denka black, or a combination thereof.

4. In paragraph 1, The above carbon nanotube is an anode which is an L-carbon nanotube.

5. In paragraph 1, The above carbon nanoparticles are anodes in which primary particles are interconnected to form aggregates.

6. In paragraph 5, An anode having an average particle diameter of the primary particles of the above carbon nanoparticles of 1 nm to 50 nm.

7. In paragraph 1, The above sulfide-based solid electrolyte is a positive electrode including an argyrodite-type sulfide-based solid electrolyte represented by the following chemical formula 11. [Chemical Formula 11] (Li a M 1 b M 2 c )(P d M 3 e )(S f M 4 g )X h In the above chemical formula 11, 4≤a≤8, and M 1 is Mg, Cu, Ag, or a combination thereof, and 0≤b<0.5, and M 2 is Na, K, or a combination thereof, 0≤c<0.5, and M 3 is Sn, Zn, Si, Sb, Ge, or a combination of these, and 0 <d<4, 0≤e<1 이고, M 4 is O, SO n , or a combination thereof, and 1.5≤n≤5, 3≤f≤12, 0≤g<2, and X is F, Cl, Br, I, or a combination thereof, and 0≤h≤2.

8. In paragraph 1, The above binder is a positive electrode which is a fluorine-based binder.

9. In paragraph 1, The above positive electrode active material layer is, with respect to 100 wt% of the positive electrode active material layer, 55 to 95 wt% of cathode active material; 0.1 wt% to 35 wt% of a sulfide-based solid electrolyte; and A cathode comprising 0.1 to 5 wt % of a binder.

10. In paragraph 1, A positive electrode further comprising a low-polarity solvent having a polarity of 0.074 to 0.281, wherein the positive electrode active material layer further comprises a low-polarity solvent having a polarity of 0.074 to 0.

281.

11. In Article 10, A positive electrode, wherein the positive electrode active material layer comprises the low-polarity solvent in an amount of 500 ppm or less based on 100 wt% of the positive electrode active material layer.

12. In paragraph 1, The above low-polarity solvent has a polarity of 0.074 to 0.281 and is selected from a pyridine solvent, a benzene solvent, an acetate solvent, a ketone solvent, an ester solvent, an ether solvent, a carbonate solvent, an acrylate solvent, an aldehyde solvent, a piperidine solvent, a sulfite solvent, an alkyl solvent, a formate solvent, or a combination thereof.

13. In paragraph 10, The above low polarity solvent is 2,6-di-tert-butylpyridine, bromobenzene, benzyl chloride, p-chlorotoluene, benzal chloride, o-dichlorobenzene, N,N-dimethylaniline, benzyl bromide, 1,2,3-trichloropropane, methoxybenzene, ethoxybenzene, 2-vinylpyridine, chlorocyclohexane, methyl laurate, ethyl chloroacetate, 2-ethylhexyl acetate, o-chlorobenzyl chloride, anisole, diethyl carbonate, ethyl trichloroacetate, n-butyl acrylate, methyl isoamyl ketone, di-tert-butyl ketone, styrene oxide, diketene, ethylhexaaldehyde, n-butyl methacrylate, diisopropyl ketone, sec-amyl acetate, methyl amyl acetate, n-Butyl propionate, n-Pentyl propionate, n-Pentyl propionate, 1-Formylpiperidine, Butyl benzonate, 4-Heptanone, 1,8-Cineole, Isobutyl methacrylate, Benzeneacetonitrile, Methyl benzoate, Isobutyl isobutyrate, Oxyl acetate, Acetylpyridine, Methyl oleate, Methyl amyl ketone, 5-Methyl-3-heptanone, Amyl formate, Diisobutyl ketone, Ethyl amyl ketone, Ethylene sulfite, Dibutyl ketone, Cyclopentanone, 2-Chloropyridine, Ethyl phenylacetate, Diethyl carbonate, Benzaldehyde, Isoamyl acetate, Methyl hexyl ketone, Ethyl benzoate, Phenyl acetate, 2,3,4-Trifluorotoluene, Butyl An anode selected from the group consisting of butyrate, 2,6-lutidine, p-anisaldehyde, n-hexyl acetate, n-butyl acetate, 1-cyanobutane, quinoline, acetic acid heptyl ester, benzyl acetate, benzyl acetate, cyclohexanone, 2,4,6-collidine, methyl decanoate, 3-heptanone, 3-picoline, methyl n-butyl ketone, isophorone, 4-ethylpyridine, 2-picoline, methyl isobutenyl ketone, 4-picoline, 2,4-lutidine, 3,4-lutidine, 3,5-lutidine, cyclohexyl acetate, triethyl phosphate or a combination thereof.

14. Dry mixing of positive electrode active material, sulfide-based solid electrolyte and carbon nanoparticles, Including adding a binder and carbon nanotubes to the obtained product of the above dry mixing and mixing them to obtain a positive electrode active material slurry, A method for manufacturing an anode, wherein the carbon nanotubes are added in an amount of 40 to 90 wt% and the carbon nanoparticles are added in an amount of 10 to 60 wt%, based on 100 wt% of the total of the carbon nanotubes and carbon nanoparticles.

15. In paragraph 14, A method for manufacturing a cathode, wherein the introduction of the binder and carbon nanotubes comprises adding a binder solution containing a binder and a first low-polarity solvent, and a carbon nanotube solution containing carbon nanotubes and a second low-polarity solvent to the obtained product of the dry mixing.

16. In paragraph 15, A method for producing a positive electrode, wherein the first low-polarity solvent and the second low-polarity solvent have a polarity of 0.074 to 0.

281.

17. In paragraph 15, A method for manufacturing a cathode, comprising first adding the binder solution to the obtained dry mixture and mixing, and then adding the carbon nanotube solution and mixing.

18. An anode according to any one of paragraphs 1 to 13; cathode; and An all-solid-state secondary battery comprising a solid electrolyte layer positioned between the positive electrode and the negative electrode.

19. In paragraph 18, The above cathode is Negative current collector; and An all-solid-state secondary battery comprising: a negative electrode coating layer positioned on the negative electrode current collector and including a lithium-philic metal, a carbon material, or a combination thereof.

20. In paragraph 19, An all-solid-state secondary battery further comprising a lithium metal layer formed by charging between the negative electrode current collector and the negative electrode coating layer.

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