Manufacturing method of cathode active material for all solid state battery

Abstract

The present invention relates to a method for manufacturing a positive electrode active material for an all-solid-state battery through sonication. The manufacturing method comprises the steps of: preparing a positive electrode active material; preparing a coating solution containing a lithium-containing precursor and a transition metal-containing precursor; preparing a mixed solution by adding the positive electrode active material to the coating solution; sonicating the mixed solution at a first temperature; and heat-treating the result of the sonication at a second temperature higher than the first temperature to form a coating layer containing a lithium transition metal oxide on the positive electrode active material layer.

Description

Technology Field

[0001] The present invention relates to a method for manufacturing a positive electrode active material for an all-solid-state battery through sonication. Background Technology

[0002] Today, secondary batteries are widely used as high-performance energy sources with high energy density, ranging from large-capacity power storage batteries for automobiles and power storage systems to small portable electronic devices such as mobile phones, camcorders, and laptops.

[0003] In particular, lithium-ion batteries, which are a type of secondary battery, have the advantages of higher energy density and capacity per unit area compared to nickel-manganese or nickel-cadmium batteries, a lower self-discharge rate, and a longer lifespan. However, as batteries for next-generation electric vehicles, lithium-ion batteries have problems such as instability due to overheating and low power output.

[0004] Because lithium-ion batteries use flammable organic solvents as electrolytes, there is a high risk of fire and explosion in the event of a short circuit caused by physical damage. Consequently, there has recently been growing interest in all-solid-state batteries that utilize solid electrolytes to enhance safety.

[0005] Solid electrolytes can be classified into sulfide-based and oxide-based solid electrolytes, and sulfide-based solid electrolytes, which have high lithium ion conductivity, are mainly used.

[0006] Meanwhile, all-solid-state batteries add a solid electrolyte to the electrode to facilitate the movement of lithium ions within the electrode; however, there is a problem regarding side reactions occurring between the sulfide-based solid electrolyte and the cathode active material. To prevent this, a coating layer was formed on the surface of the cathode active material to suppress the side reactions between the cathode active material and the sulfide-based solid electrolyte. Prior art literature

[0007] Korean Published Patent No. 10-2020-0047960, Korean Published Patent No. 10-2019-0067465, Korean Published Patent No. 10-2018-0071438 The problem to be solved

[0008] The present invention aims to provide a method for manufacturing a positive electrode active material capable of reducing resistance within the electrode and improving the performance of the battery.

[0009] The objectives of the present invention are not limited to those mentioned above. The objectives of the present invention will become more apparent from the following description and will be realized by the means and combinations thereof described in the claims. means of solving the problem

[0010] A method for manufacturing a positive electrode active material for an all-solid-state battery according to one embodiment of the present invention may include: a step of preparing a positive electrode active material; a step of preparing a coating solution containing a lithium-containing precursor and a transition metal-containing precursor; a step of preparing a mixed solution by introducing the positive electrode active material into the coating solution; a step of sonicating the mixed solution at a first temperature; and a step of heat-treating the result of the sonication.

[0011] The above positive active material may include an oxide-based positive active material.

[0012] The above positive active material is LiNi1 -x- y Co x Mn y Al z O2(x, y and z may include 0<x, 0<y, 0<z, 0<x+y+z≤0.4).

[0013] The above lithium-containing precursor may include lithium ethoxide.

[0014] The above transition metal-containing precursor may include at least one selected from the group consisting of niobium ethoxide, vanadium ethoxide, zirconium ethoxide, and combinations thereof.

[0015] Through the above sound wave treatment, energy can be transferred to the mixed solution to an extent that prevents metal from precipitating from the lithium-containing precursor and the transition metal-containing precursor.

[0016] The first temperature mentioned above may be 50 ℃ to 70 ℃.

[0017] Through the above sound wave treatment, the solvent of the mixed solution can be removed to obtain a powder-state product.

[0018] The results of sound wave processing can be heat-treated in an oxygen atmosphere.

[0019] The above heat treatment can be performed at 300 ℃ to 350 ℃.

[0020] The heat-treated product comprises a core layer containing a positive electrode active material; and a coating layer coated on all or part of the surface of the core layer, wherein the coating layer is LiNbO3, LiNb3O8, Li3NbO4, LiNbO2, Li8Nb2O9, LiV3O8, LiVO2, LiVO4, Li3VO4, LiVO3, LiV2O5, LiV2O4, Li2V 18 O 39 , LiV6O 13 , Li2V6O 13 It may include at least one selected from the group consisting of Li2ZrO3, Li6Zr2O7 and combinations thereof.

[0021] A method for manufacturing a positive electrode for an all-solid-state battery according to one embodiment of the present invention may include the step of preparing a starting material comprising a positive electrode active material and a solid electrolyte prepared by the above-described method; and the step of manufacturing a positive electrode using the starting material.

[0022] The above solid electrolyte may include a sulfide-based solid electrolyte.

[0023] The above anode has an ionic conductivity of 4.0 × 10 -4 S / cm to 6.0 × 10 -4 It could be S / cm. Effects of the invention

[0024] According to the present invention, a coating layer can be evenly formed on the surface of the positive electrode active material, thereby reducing resistance within the electrode and improving the performance of the battery.

[0025] The effects of the present invention are not limited to those mentioned above. It should be understood that the effects of the present invention include all effects that can be inferred from the following description. Brief explanation of the drawing

[0026] FIG. 1 is a cross-sectional view illustrating an all-solid-state battery according to the present invention. FIG. 2 illustrates an anode active material coated with a coating layer according to the present invention. FIG. 3 illustrates an exemplary sound wave processing device according to the present invention. Figure 4a is the result of analyzing an anode prepared with the anode active material according to Example 1 using impedance spectroscopy. Figure 4b is the result of analyzing an anode prepared with the anode active material according to Example 2 using impedance spectroscopy. Figure 4c shows the results of analyzing an anode prepared with the anode active material according to Comparative Example 1 using impedance spectroscopy. Figure 4d shows the results of analyzing an anode prepared with the anode active material according to Comparative Example 2 using impedance spectroscopy. Specific details for implementing the invention

[0027] The above objects, other objects, features, and advantages of the present invention will be easily understood through the following preferred embodiments associated with the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided to ensure that the disclosed content is thorough and complete, and to ensure that the spirit of the invention is sufficiently conveyed to a person skilled in the art.

[0028] In describing each drawing, similar reference numerals have been used for similar components. In the attached drawings, the dimensions of the structures are depicted enlarged from their actual size for clarity of the invention. Terms such as "first," "second," etc., may be used to describe various components, but said components should not be limited by said terms. These terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the invention, the first component may be named the second component, and similarly, the second component may be named the first component. A singular expression includes a plural expression unless the context clearly indicates otherwise.

[0029] In this specification, terms such as "comprising" or "having" are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof. Furthermore, when a part such as a layer, film, region, or plate is described as being "on" another part, this includes not only the case where it is "immediately above" the other part, but also the case where there is another part in between. Conversely, when a part such as a layer, film, region, or plate is described as being "below" another part, this includes not only the case where it is "immediately below" the other part, but also the case where there is another part in between.

[0030] Unless otherwise specified, all numbers, values, and / or expressions used herein to represent amounts of ingredients, reaction conditions, polymer compositions, and formulations should be understood to be modified by the term “approximately” in all cases, as these numbers are essentially approximations reflecting the various uncertainties of measurement that occur in obtaining these values ​​among other things. Furthermore, where numerical ranges are disclosed herein, such ranges are continuous and, unless otherwise indicated, include all values ​​from the minimum value of such range to the maximum value including said maximum value. Moreover, where such ranges refer to integers, they include all integers from the minimum value to said maximum value including said maximum value, unless otherwise indicated.

[0032] FIG. 1 is a cross-sectional view illustrating an all-solid-state battery according to the present invention. The all-solid-state battery (1) may include a positive electrode (10), a negative electrode (20), and a solid electrolyte layer (30) located between the positive electrode (10) and the negative electrode (20).

[0033] (anode)

[0034] The above anode (10) may include an anode active material, a solid electrolyte, a conductive material, a binder, etc.

[0035] FIG. 2 illustrates a positive active material (11) coated with a coating layer (12) according to the present invention. The positive active material (11) may form a core layer, and the coating layer (12) may be coated on all or part of the surface of the core layer.

[0036] The above positive active material (11) may include an oxide-based positive active material. For example, the above positive active material (11) may include LiCoO2, LiMnO2, LiNiO2, LiVO2, LiNi1 -x- y Co x Mn y Al zRock salt layer type active materials such as O2 (x, y, and z are 0 < x, 0 < y, 0 < z, 0 < x+y+z ≤ 0.4); LiMn2O4, Li(Ni 0.5 Mn 1.5 Spinel-type active materials such as )O4; inverse spinel-type active materials such as LiNiVO4, LiCoVO4, etc.; olivine-type active materials such as LiFePO4, LiMnPO4, LiCoPO4, LiNiPO4, etc.; silicon-containing active materials such as Li2FeSiO4, Li2MnSiO4, LiNiO . 8Co (0.2-x) Al x A salt-layered active material in which a portion of the transition metal is replaced with a heterogeneous metal, such as O2 (0 < x < 0.2); Li1 + x Mn2 -x- y M y Spinel-type active material in which a portion of the transition metal is substituted with a heterogeneous metal, such as O4 (M is at least one of Al, Mg, Co, Fe, Ni, Zn and 0 < x + y < 2); Li4Ti5O 12 It may include lithium titanate, etc.

[0037] Preferably, the positive active material (11) is LiNi1 -x- y Co x Mn y Al z O2(x, y and z may include 0<x, 0<y, 0<z, 0<x+y+z≤0.4).

[0038] The coating layer (12) is configured to cover the positive active material (11) to prevent the positive active material (11) from coming into contact with the solid electrolyte.

[0039] The coating layer (12) may include a lithium transition metal oxide. For example, the coating layer (12) may include LiNbO3, LiV3O8, It may include at least one selected from the group consisting of Li2ZrO3 and combinations thereof.

[0040] The present invention relates to a method for manufacturing a positive electrode active material capable of uniformly forming the coating layer (12). Specifically, the manufacturing method may include the steps of: preparing a positive electrode active material (S1); preparing a coating solution containing a lithium-containing precursor and a transition metal-containing precursor (S2); preparing a mixed solution by adding the positive electrode active material to the coating solution (S3); sonicating the mixed solution at a first temperature (S4); and heat-treating the result of the sonication at a second temperature higher than the first temperature to form a coating layer containing a lithium transition metal oxide on the positive electrode active material (S5).

[0041] The step (S1) of preparing the above-mentioned positive active material may be to prepare the above-mentioned positive active material in a powder state.

[0042] The step (S2) of preparing the coating solution may involve dissolving a lithium-containing precursor or a transition metal-containing precursor, which are precursors of the coating layer, in an organic solvent such as anhydrous ethanol.

[0043] The above lithium-containing precursor may include lithium ethoxide.

[0044] The above transition metal-containing precursor may include at least one selected from the group consisting of niobium ethoxide, vanadium ethoxide, zirconium ethoxide, and combinations thereof.

[0045] A mixed solution can be obtained by adding the positive active material to the coating solution (S3).

[0046] The content of the positive electrode active material, the lithium-containing precursor, and the transition metal-containing precursor in the above mixed solution is not particularly limited and can be appropriately adjusted according to the type, thickness, etc. of the coating layer (12). For example, the above mixed solution may contain 0.3 to 2 parts by weight of the lithium-containing precursor based on 100 parts by weight of the positive electrode active material. In addition, the above mixed solution may contain 0.2 to 2 parts by weight of the transition metal-containing precursor based on 100 parts by weight of the positive electrode active material. When two components among niobium ethoxide, vanadium ethoxide, and zirconium ethoxide are used as the transition metal-containing precursor, they may be combined in a weight ratio of 1:9 to 9:1.

[0047] The present invention is characterized by sonicating the above-mentioned mixed solution at a certain temperature to form a gel-state coating layer derived from the coating solution on the surface of the above-mentioned positive active material (11).

[0048] FIG. 3 illustrates an exemplary sound wave processing device according to the present invention. Referring thereto, the sound wave processing may involve immersing a mixed solution containing a positive active material (11) and a coating solution (40) contained in a container of a certain shape into a sound wave processing tank containing a medium, and then generating sound waves using a probe (not shown) to transfer energy to the mixed solution through the medium.

[0049] According to the present invention, by vibrating the positive electrode active material through the sound wave treatment, a gel-state coating layer can be evenly coated on its surface. However, it may be preferable to perform the sound wave treatment under mild conditions so that metals do not precipitate from the lithium-containing precursor or the transition metal-containing precursor due to the energy transferred to the mixed solution through the sound wave treatment. If metals precipitate, it may be difficult to induce a gel-state coating layer from the coating solution, and the surface of the positive electrode active material may not be evenly coated. Specifically, the sound wave treatment can be performed under a first temperature condition of 50°C to 70°C. The first temperature condition can be controlled through the intensity of the sound waves, etc. Furthermore, the sound wave treatment can be performed until the solvent of the mixed solution is removed and a powder-state product is obtained. Here, "product in powder form" does not mean that liquid components such as moisture have been completely removed, but rather means a product in which the solvent of the above-mentioned mixed solution has been removed by 70% or more, or 80% or more, or 90% or more, or 95% or more.

[0050] Afterwards, the sound-processed product can be heat-treated to form a coating layer containing a lithium transition metal oxide on the positive electrode active material (S5).

[0051] The above lithium transition metal oxide can be obtained by oxidizing a gel-state coating layer derived from the above lithium-containing precursor and the transition metal-containing precursor through heat treatment in an oxygen atmosphere.

[0052] The above heat treatment can be performed in an oxygen atmosphere under a second temperature condition of 300°C to 350°C. The time of the above heat treatment is not particularly limited and can be performed for a period of time sufficient to prevent damage to the anode active material and the coating layer, for example, from 1 hour to 24 hours, or from 1 hour to 12 hours, or from 1 hour to 6 hours, or from 1 hour to 3 hours.

[0053] The above solid electrolyte may be an oxide-based solid electrolyte or a sulfide-based solid electrolyte. However, it may be preferable to use a sulfide-based solid electrolyte with high lithium ion conductivity.

[0054] The sulfide-based solid electrolyte is Li2S-P2S5, Li2S-P2S5-LiI, Li2S-P2S5-LiCl, Li2S-P2S5-LiBr, Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z m S n (where m and n are positive numbers, and Z is one of Ge, Zn, or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li x MO y (where x and y are positive numbers, and M is one of P, Si, Ge, B, Al, Ga, or In), Li 10 GeP2S 12 , Li3 - 2X M X In1 - Y M' Y L6 - Z L' Z (In the formula, M and M' are metallic elements and L and L' are halogen elements. Also, X, Y and Z independently satisfy 0≤X<1.5, 0≤Y<1, 0≤Z≤6) etc.

[0055] Preferably, the solid electrolyte is Li3 - 2X M X In1 - Y M' Y L6 - Z L' Z(In the formula, M and M' are metallic elements and L and L' are halogen elements. Also, X, Y and Z independently satisfy 0≤X<1.5, 0≤Y<1, and 0≤Z≤6) may be included.

[0056] The conductive material is configured to form an electron conduction path within the anode (10). The conductive material is a sp such as carbon black, conducting graphite, ethylene black, carbon nanotube, etc. 2 It can be a carbon material or graphene.

[0057] The above binder may include BR (Butadiene rubber), NBR (Nitrile butadiene rubber), HNBR (Hydrogenated nitrile butadiene rubber), PVDF (polyvinylidene difluoride), PTFE (polytetrafluoroethylene), CMC (carboxymethylcellulose), etc.

[0058] The method for manufacturing the anode according to the present invention may include the step of preparing a starting material comprising the anode active material, a solid electrolyte, etc., and the step of manufacturing the anode using the starting material.

[0059] The above starting material may be a slurry obtained by adding the above positive active material, solid electrolyte, binder, conductive material, etc. to a solvent. The above slurry may be applied onto a substrate and dried to manufacture a positive electrode.

[0060] Meanwhile, the above starting material may be a powder containing the above positive active material, solid electrolyte, conductive material, etc. The positive electrode can be manufactured by introducing the powder into a mold of a certain shape and applying a predetermined pressure.

[0061] (cathode)

[0062] The above cathode (20) may include a cathode active material, a solid electrolyte, a binder, etc.

[0063] The above-mentioned cathode active material is not particularly limited and may be, for example, a carbon active material or a metal active material.

[0064] The above carbon active material may be amorphous carbon such as graphite, hard carbon, and soft carbon, such as mesocarbon microbeads (MCMB) and highly oriented graphite (HOPG).

[0065] The above metal active material may be an alloy containing at least one of In, Al, Si, Sn, and elements thereof.

[0066] The above solid electrolyte may be an oxide-based solid electrolyte or a sulfide-based solid electrolyte. However, it may be preferable to use a sulfide-based solid electrolyte with high lithium ion conductivity.

[0067] The sulfide-based solid electrolyte is Li2S-P2S5, Li2S-P2S5-LiI, Li2S-P2S5-LiCl, Li2S-P2S5-LiBr, Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z m S n (where m and n are positive numbers, and Z is one of Ge, Zn, or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li x MO y (where x and y are positive numbers, and M is one of P, Si, Ge, B, Al, Ga, or In), Li 10 GeP2S 12 , Li3 - 2X M X In1 - Y M' Y L6- Z L' Z (In the formula, M and M' are metallic elements and L and L' are halogen elements. Also, X, Y and Z independently satisfy 0≤X<1.5, 0≤Y<1, 0≤Z≤6) etc.

[0068] Preferably, the solid electrolyte is Li3 - 2X M X In1 - Y M' Y L6 - Z L' Z (In the formula, M and M' are metallic elements and L and L' are halogen elements. Also, X, Y and Z independently satisfy 0≤X<1.5, 0≤Y<1, and 0≤Z≤6) may be included.

[0069] The solid electrolyte contained in the above cathode (20) may be the same as or different from that contained in the above anode (10).

[0070] The above binder may include BR (Butadiene rubber), NBR (Nitrile butadiene rubber), HNBR (Hydrogenated nitrile butadiene rubber), PVDF (polyvinylidene difluoride), PTFE (polytetrafluoroethylene), CMC (carboxymethylcellulose), etc.

[0071] The binder included in the above cathode (20) may be the same as or different from that included in the above anode (10).

[0072] Additionally, the above-mentioned negative electrode (20) may not include a negative electrode active material. Specifically, the all-solid-state battery according to the present invention may be an anodeless type that excludes a negative electrode active material and directly deposits lithium on the negative electrode current collector side. In this case, the above-mentioned negative electrode (20) may include a carbon material and a metal capable of alloying with lithium.

[0073] The above carbon material may be an amorphous carbon material that does not function as a negative electrode active material.

[0074] The above metal may include at least one selected from the group consisting of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), zinc (Zn), and combinations thereof.

[0075] (Solid electrolyte layer)

[0076] The solid electrolyte layer (30) is positioned between the positive electrode (10) and the negative electrode (20) to allow lithium ions to move between the two electrodes.

[0077] The above solid electrolyte layer (30) may include a solid electrolyte and a binder.

[0078] The above solid electrolyte may be an oxide-based solid electrolyte or a sulfide-based solid electrolyte. However, it may be preferable to use a sulfide-based solid electrolyte with high lithium ion conductivity.

[0079] The sulfide-based solid electrolyte is Li2S-P2S5, Li2S-P2S5-LiI, Li2S-P2S5-LiCl, Li2S-P2S5-LiBr, Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z m S n (where m and n are positive numbers, and Z is one of Ge, Zn, or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li x MO y (where x and y are positive numbers, and M is one of P, Si, Ge, B, Al, Ga, or In), Li 10 GeP2S 12, Li3 - 2X M X In1 - Y M' Y L6 - Z L' Z (In the formula, M and M' are metallic elements and L and L' are halogen elements. Also, X, Y and Z independently satisfy 0≤X<1.5, 0≤Y<1, 0≤Z≤6) etc.

[0080] Preferably, the solid electrolyte is Li3 - 2X M X In1 - Y M' Y L6 - Z L' Z (In the formula, M and M' are metallic elements and L and L' are halogen elements. Also, X, Y and Z independently satisfy 0≤X<1.5, 0≤Y<1, and 0≤Z≤6) may be included.

[0081] The solid electrolyte contained in the solid electrolyte layer (30) may be the same as or different from that contained in the anode (10) and cathode (20).

[0082] The above binder may include BR (Butadiene rubber), NBR (Nitrile butadiene rubber), HNBR (Hydrogenated nitrile butadiene rubber), PVDF (polyvinylidene difluoride), PTFE (polytetrafluoroethylene), CMC (carboxymethylcellulose), etc.

[0083] The binder included in the solid electrolyte layer (30) may be the same as or different from that included in the anode (10) and cathode (20).

[0085] The present invention will be explained in more detail below through specific embodiments. The following embodiments are merely examples to aid in understanding the present invention and do not limit the scope of the present invention.

[0087] Example 1

[0088] (S1) LiNiO as the positive active material . 8Co0 . 1Mn0 . I prepared 102.

[0089] (S2) A coating solution was prepared by dissolving 0.3 parts by weight of lithium ethoxide, 1.8 parts by weight of niobium ethoxide, and 0.2 parts by weight of vanadium ethoxide in ethanol based on 100 parts by weight of positive electrode active material.

[0090] (S3) A positive active material was added to the above coating solution to obtain a mixed solution.

[0091] (S4) The above mixed solution was sonicated using a device as shown in Fig. 3. The sonication was performed at approximately 60°C, and a powdered product was obtained in which the solvent was removed to a certain level.

[0092] (S5) The result of the sound wave treatment was heat-treated at 370°C for 3 hours in an oxygen atmosphere to obtain an anode active material coated with a coating layer.

[0094] Example 2

[0095] LiNiO as the positive active material . 7Co0 . 15 Mn0 . 15 A positive electrode active material was prepared in the same manner as in Example 1 above, except that O2 was used.

[0097] Comparative Example 1

[0098] A positive electrode active material was prepared in the same manner as in Example 1 above, except that the solvent was removed by applying only heat to the mixed solution without sonication.

[0100] Comparative Example 2

[0101] LiNiO as the positive active material . 7Co0 . 15 Mn0 . 15 A positive electrode active material was prepared using the same method as Comparative Example 1 above, except that O2 was used.

[0103] Experimental Example 1

[0104] Each of the positive active materials of Example 1, Example 2, Comparative Example 1, and Comparative Example 2 was mixed with a solid electrolyte in a weight ratio of 8:2. 0.3g of the mixture was placed in a mold with a diameter of 13mm and uniaxially compressed at a pressure of about 500 MPa to produce a positive electrode in the form of a pellet.

[0105] After connecting SUS electrodes to both sides of the anode, the electrochemical characteristics of the anode were evaluated using impedance spectroscopy in a frequency range of 1 MHz to 0.01 Hz.

[0106] Figures 4a to 4d show the results of analyzing anodes prepared with the positive active materials according to Example 1, Example 2, Comparative Example 1, and Comparative Example 2, respectively, using impedance spectroscopy. Based on these results, the ionic conductivity of each sample was calculated. This is as shown in Table 1 below.

[0107] division Ionic conductivity [S / cm] Example 1 4.5 × 10 -4 Comparative Example 1 3.2 × 10 -4 Example 2 4.8 × 10 -4 Comparative Example 2 2.9 × 10 -4

[0108] Since the thickness of the samples according to the above Examples 1 and 2, and Comparative Examples 1 and 2 is all the same, a high ionic conductivity of the sample can be interpreted as having low ionic resistance. Here, ionic conductivity refers to lithium-ion conductivity.

[0109] Referring to Table 1, the ionic conductivity of the anode prepared with the anode active material according to Example 1 and Example 2 is 4.0 × 10⁻⁶ -4It can be seen that the ionic conductivity is higher than S / cm compared to Comparative Examples 1 and 2. This means that Examples 1 and 2 have lower ionic resistance compared to Comparative Examples 1 and 2.

[0110] As a result, it can be seen that according to the present invention, a coating layer can be formed more evenly on the positive electrode active material, and accordingly, the performance of the battery can be improved.

[0112] As the present invention has been described in detail above, the scope of the present invention is not limited to the experimental examples and embodiments described above, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the following claims are also included within the scope of the present invention. Explanation of the symbols

[0113] 10: Anode 20: Cathode 30: Solid electrolyte layer 11: Anode active material 12: Coating layer 40: Coating solution

Claims

Claim 1 A method for manufacturing a positive electrode active material for an all-solid-state battery, comprising: a step of preparing a positive electrode active material; a step of preparing a coating solution containing a lithium-containing precursor and a transition metal-containing precursor; a step of preparing a mixed solution by introducing the positive electrode active material into the coating solution; a step of sonicating the mixed solution at a first temperature; and a step of heat-treating the result of the sonication; wherein the lithium-containing precursor includes lithium ethoxide, and the transition metal-containing precursor includes niobium ethoxide and vanadium ethoxide. Claim 2 A method for manufacturing a positive active material for an all-solid-state battery, wherein the positive active material comprises an oxide-based positive active material. Claim 3 In claim 1, the positive active material is LiNi1 -x- y Co x Mn y Al z A method for manufacturing a positive electrode active material for an all-solid-state battery comprising O2 (where x, y and z are 0 < x, 0 < y, 0 < z, 0 < x+y+z ≤ 0.4). Claim 4 A method for manufacturing a positive electrode active material for an all-solid-state battery according to claim 1, wherein energy is transferred to a mixed solution such that metal is not precipitated from a lithium-containing precursor and a transition metal-containing precursor through the sound wave treatment. Claim 5 A method for manufacturing a positive electrode active material for an all-solid-state battery according to claim 1, wherein the first temperature is 50 ℃ to 70 ℃. Claim 6 A method for manufacturing a positive electrode active material for an all-solid-state battery, wherein, in claim 1, the solvent of the mixed solution is removed through the sound wave treatment to obtain a product in a powder state. Claim 7 A method for manufacturing a positive electrode active material for an all-solid-state battery, wherein, in claim 1, the result of sound wave treatment is heat-treated in an oxygen atmosphere. Claim 8 A method for manufacturing a positive electrode active material for an all-solid-state battery according to claim 1, wherein the heat treatment is performed at 300 ℃ to 350 ℃. Claim 9 In claim 1, the heat-treated product comprises a core layer containing an anode active material; and a coating layer coated on all or part of the surface of the core layer, wherein the coating layer comprises LiNbO3, LiNb3O8, Li3NbO4, LiNbO2, Li8Nb2O9, LiV3O8, LiVO2, LiVO4, Li3VO4, LiVO3, LiV2O5, LiV2O4, Li2V 18 O 39 , LiV6O 13 , Li2V6O 13 A method for manufacturing a positive electrode active material for an all-solid-state battery comprising at least one selected from the group consisting of combinations thereof. Claim 10 A method for manufacturing a positive electrode for an all-solid-state battery, comprising: a step of preparing a starting material comprising a positive electrode active material and a solid electrolyte according to any one of claims 1 to 9; and a step of manufacturing a positive electrode using said starting material. Claim 11 In claim 10, the above solid electrolyte is a method for manufacturing a positive electrode for an all-solid-state battery comprising a sulfide-based solid electrolyte. Claim 12 In item 10, the anode has an ionic conductivity of 4.0 × 10 -4 S / cm to 6.0 × 10 -4 Method for manufacturing a positive electrode for an all-solid-state battery with S / cm. Claim 13 delete Claim 14 delete

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