Method for manufacturing composite positive electrode for all-solid-state battery, composite positive electrode manufactured thereby, and all-solid-state battery comprising same

Abstract

The present invention provides a method for manufacturing a composite positive electrode for an all-solid-state battery, a composite positive electrode manufactured thereby, and an all-solid-state battery comprising same, wherein performance degradation of the composite positive electrode obtained by mixing a sulfide solid electrolyte and positive electrode active material particles coated with a hybrid material of an inorganic material and an organic polymer material is suppressed, and the all-solid-state battery exhibits stable characteristics in charge-discharge cycle behavior.

Description

Method for manufacturing a composite cathode for an all-solid-state battery, a composite cathode manufactured by the method, and an all-solid-state battery including the same

[0001] The present invention relates to a method for manufacturing a composite cathode for an all-solid-state battery, a composite cathode manufactured by the method, and an all-solid-state battery including the same. More specifically, the invention relates to a method for manufacturing a composite cathode for an all-solid-state battery in which a hybrid material of an inorganic material and an organic polymer material is coated onto cathode active material particles and mixed with a sulfide solid electrolyte to suppress performance degradation of the composite cathode and exhibit stable characteristics in the charge-discharge cycle behavior of the all-solid-state battery, a composite cathode manufactured by the method, and an all-solid-state battery including the same.

[0002] As various markets utilizing lithium-ion batteries—including mobile electronic devices such as smartphones and laptops, as well as eco-friendly transportation like electric vehicles and electric buses, and energy storage systems for large-scale power storage—grow rapidly, there is a growing need for lithium-ion batteries with superior stability and energy density.

[0003] Among the solid electrolytes being actively researched and developed in industry and academia, oxide-based solid electrolytes have problems such as difficulty in forming an interface with the electrode active material and difficulty in realizing large-area cells, while polymer-based solid electrolytes have issues such as low ionic conductivity and mechanical properties, as well as high operating temperatures.

[0004] In contrast, sulfide-based solid electrolytes are attracting the attention of researchers due to their high ionic conductivity, comparable to that of liquid electrolytes, and the advantage of smooth interface formation with electrode active materials when a pressurized method is applied. Accordingly, there is an expectation that all-solid-state batteries based on sulfide electrolytes can be developed to the extent that they can replace secondary batteries using liquid electrolytes.

[0005] However, sulfide electrolytes are highly reactive, which leads to side reactions upon contact with the cathode active material, posing a problem of weak cycle life stability in all-solid-state batteries and acting as an obstacle to commercialization.

[0006] To address these issues, research is being conducted to improve the stability of the cathode active material / solid electrolyte interface by coating the surface of the cathode active material with various materials that possess lithium ion transport characteristics while suppressing electron transport. For example, ion-conducting inorganic materials such as Lithium Niobate (LiNbO3) and Lithium Titanate (Li4Ti5O3) are coated on the cathode active material. 12 The method of coating the positive electrode active material and the sulfide solid electrolyte prevents direct contact between the positive electrode active material and the sulfide solid electrolyte, thereby increasing chemical stability and electrochemical stability.

[0007] However, while inorganic materials possess high mechanical strength, their flexibility is poor. Consequently, physical damage to the inorganic coating layer can occur due to volume changes in the cathode active material that inevitably occur during the repeated charging and discharging of all-solid-state batteries, and such damage can ultimately lead to a reduction in the cycle life of the all-solid-state battery.

[0008] Accordingly, through strenuous efforts and various studies, the applicant has devised a method for manufacturing a composite cathode for an all-solid-state battery that suppresses performance degradation of a composite cathode mixed with a sulfide solid electrolyte and exhibits stable characteristics in the charge-discharge cycle behavior of the all-solid-state battery by coating a hybrid material of an inorganic material with excellent ionic conductivity, electrochemical stability, and mechanical strength and an organic polymer material with excellent ionic conductivity, electrochemical stability, and flexibility onto cathode active material particles, a composite cathode manufactured by said method, and an all-solid-state battery including said method.

[0009] The present invention, which aims to solve the aforementioned conventional problems, provides a method for manufacturing a composite cathode for an all-solid-state battery and a composite cathode manufactured by the same method, wherein a hybrid material comprising an inorganic material having excellent ion conductivity, electrochemical stability, and mechanical strength and an organic polymer material having excellent ion conductivity, electrochemical stability, and flexibility is coated onto cathode active material particles to suppress side reactions occurring at the interface with a sulfide solid electrolyte and lower interfacial resistance to improve electrochemical stability.

[0010] In addition, the present invention provides a method for manufacturing a composite cathode for an all-solid-state battery that suppresses performance degradation of the composite cathode caused by volume change of the cathode active material during the charging and discharging process and improves charge-discharge cycle life characteristics, and a composite cathode manufactured by the same method.

[0011] In addition, the present invention provides an all-solid-state battery with excellent efficiency that has improved capacity retention rate in charge-discharge cycle behavior and stable characteristics even at high rate speeds.

[0012] The problems that the present invention aims to solve are not limited to those mentioned above, and other unmentioned problems will be clearly understood by those skilled in the art from the description below.

[0013] To achieve the above objective, according to one aspect of the present invention, a method for manufacturing a composite cathode for an all-solid-state battery comprises:

[0014] (a) a step of mixing a coating solution and positive active material particles to coat the surface of the positive active material particles with lithium niobate (LiNbO3);

[0015] (b) a step of preparing a polymer solution by adding a polycarbonate-based polymer and a lithium salt to an organic solvent;

[0016] (c) a step of preparing a mixture by mixing the above-mentioned coated positive active material particles, a sulfide solid electrolyte, and a conductive material; and

[0017] (d) a step of mixing the above mixture and the above polymer solution, heating, and then obtaining a composite anode; is included.

[0018] In addition, the positive electrode active material particles are characterized as being lithium transition metal oxides.

[0019] In addition, the weight ratio of the positive active material particles and the lithium niobate coating layer after step (a) is characterized as being 100:0.1 to 100:0.5.

[0020] In addition, in step (b) above, the polycarbonate-based polymer is characterized by being one or more selected from the group consisting of polypropylene carbonate, polydimethyl carbonate, polydiethyl carbonate, polydipropyl carbonate, polyethylmethyl carbonate, polymethylpropyl carbonate, polyethylpropyl polycarbonate, and polyethylene carbonate.

[0021] In addition, in step (b) above, the lithium salt is lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium hexafluorophosphate (LiPF6), lithium hexafluoroantimonate (LiSbF6), lithium hexafluoroarsenate (LiAsF6), lithium difluoromethane sulfonate (LiC4F9SO3), lithium perchlorate (LiClO4), lithium aluminate (LiAlO2), lithium tetrachloroaluminate (LiAlCl4), lithium chloride (LiCl), and It is characterized by being one or more selected from the group consisting of lithium iodide (LiI).

[0022] In addition, the molar ratio of the polycarbonate-based polymer and the lithium salt in step (b) above is characterized as being 5:1 to 15:1.

[0023] In addition, the organic solvent in step (b) above is characterized as being a diethyl carbonate solvent.

[0024] In addition, in step (c) above, the sulfide solid electrolyte is Li6PS5Cl, Li6PS5, Li7P3S 11 , Li3PS4, Li 10 GeP2S 12, Li3PO4-Li2S-Si2S, Li2S-SiS2, LiI-Li2S-P2S5, Li2S-P2S5, LiI-Li3PO4-P2S5, LiI-Li2S-B2S3, Li3PO4-Li2S-SiS2, LiPO4-Li2S-SiS, LiI-Li2S-P2O5, LiI-Li2S-SiS2, Li2S-P2S5-LiCl, Li7P3S 11 It is characterized by being one or more selected from a group consisting of

[0025] In addition, in step (c) above, the conductive material is characterized by being one or more selected from the group consisting of carbon nanofibers, carbon nanotubes, and carbon black.

[0026] In addition, the above-mentioned (c) step is characterized by the fact that, with respect to the total composition, the coated positive active material particles comprise 60 to 95 weight%, the sulfide solid electrolyte comprises 4 to 37 weight%, and the conductive material comprises 1 to 10 weight%.

[0027] In addition, in step (d) above, the mixture and the polymer solution are sequentially mixed in a weight ratio of 100:10 to 15.

[0028] To achieve the above objective, according to another aspect of the present invention, the composite anode is characterized by being manufactured by a method for manufacturing a composite anode for an all-solid-state battery.

[0029] In addition, the above composite cathode is characterized by a weight ratio of cathode active material particles to a lithium niobate coating layer of 100:0.1 to 100:0.5.

[0030] In addition, the above composite anode is characterized by having a polycarbonate-based polymer disposed on a portion of the surface of the anode active material particles.

[0031] To achieve the above objective, according to another aspect of the present invention, an all-solid-state battery comprises the composite cathode described above.

[0032] According to the present invention, a method for manufacturing a composite cathode for an all-solid-state battery is provided, wherein a hybrid material of an inorganic material and an organic polymer material is coated onto cathode active material particles to suppress side reactions occurring at the interface with a sulfide solid electrolyte and to lower interfacial resistance, thereby improving electrochemical stability.

[0033] In addition, the present invention provides a method for manufacturing a composite cathode for an all-solid-state battery that suppresses performance degradation of the composite cathode caused by volume change of the cathode active material during the charging and discharging process and improves charge-discharge cycle life characteristics.

[0034] In addition, according to the present invention, a composite cathode for an all-solid-state battery is provided, in which a hybrid material of an inorganic material and an organic polymer material is coated onto cathode active material particles to suppress side reactions occurring at the interface with a sulfide solid electrolyte and lower interfacial resistance, thereby improving electrochemical stability.

[0035] In addition, the present invention provides a composite cathode for an all-solid-state battery that suppresses performance degradation of the composite cathode caused by volume change of the cathode active material during the charging and discharging process and improves charge-discharge cycle life characteristics.

[0036] In addition, we provide an all-solid-state battery with excellent efficiency that has improved capacity retention rate in charge-discharge cycle behavior and stable characteristics even at high rate rates.

[0037] The effects of the present invention are not limited to the effects described above, and should be understood to include all effects that can be inferred from the configuration of the invention described in the detailed description of the invention or the claims.

[0038] FIG. 1 is a process diagram showing a method for manufacturing a composite cathode for an all-solid-state battery according to the present invention.

[0039] Figure 2 is a graph of resistance over time of an all-solid-state battery including the composite cathode of Comparative Example 1 of the present invention.

[0040] Figure 3 is a graph of the resistance over time of an all-solid-state battery including the composite anode of Example 3 of the present invention.

[0041] Figure 4 is a graph showing the results of evaluating the rate capability of an all-solid-state battery including the composite cathode of Comparative Example 1 of the present invention.

[0042] Figure 5 is a graph showing the results of evaluating the rate capability of an all-solid-state battery including the composite cathode of Example 1 of the present invention.

[0043] Figure 6 is a graph showing the results of evaluating the rate capability of an all-solid-state battery including the composite cathode of Example 2 of the present invention.

[0044] Figure 7 is a graph showing the results of evaluating the rate capability of an all-solid-state battery including the composite cathode of Example 3 of the present invention.

[0045] FIG. 8 is a graph comparing the discharge capacity of the rate capability characteristics of all-solid-state batteries including the composite cathodes of Comparative Example 1, Example 1, Example 2, and Example 3 of the present invention.

[0046] Figure 9 is a graph showing the results of evaluating the cycle characteristics of an all-solid-state battery including the composite cathode of Comparative Example 1 of the present invention.

[0047] Figure 10 is a graph showing the results of evaluating the cycle characteristics of an all-solid-state battery including the composite cathode of Example 1 of the present invention.

[0048] Figure 11 is a graph showing the results of evaluating the cycle characteristics of an all-solid-state battery including the composite cathode of Example 2 of the present invention.

[0049] Figure 12 is a graph showing the results of evaluating the cycle characteristics of an all-solid-state battery including the composite cathode of Example 3 of the present invention.

[0050] FIG. 13 is a graph comparing the discharge capacity of the cycle characteristics of all-solid-state batteries including the composite cathodes of Comparative Example 1, Example 1, Example 2, and Example 3 of the present invention.

[0051] FIG. 14 is a graph comparing the capacity retention rate of the cycle characteristics of all-solid-state batteries including the composite cathodes of Comparative Example 1, Example 1, Example 2, and Example 3 of the present invention.

[0052] The present invention provides a method for manufacturing a composite cathode for an all-solid-state battery and a composite cathode manufactured by the same, wherein a hybrid material comprising an inorganic material having excellent ionic conductivity, electrochemical stability, and mechanical strength and an organic polymer material having excellent ionic conductivity, electrochemical stability, and flexibility is coated onto cathode active material particles to suppress side reactions occurring at the interface with a sulfide solid electrolyte and lower interfacial resistance to improve electrochemical stability.

[0053] In addition, the present invention provides a method for manufacturing a composite cathode for an all-solid-state battery that suppresses performance degradation of the composite cathode caused by volume change of the cathode active material during the charging and discharging process and improves charge-discharge cycle life characteristics, and a composite cathode manufactured by the same method.

[0054] In addition, the present invention provides an all-solid-state battery with excellent efficiency that has improved capacity retention rate in charge-discharge cycle behavior and stable characteristics even at high rate speeds.

[0055] Before describing the present invention in detail, it should be understood that the terms and words used in this specification should not be interpreted as being limited to their ordinary or dictionary meanings, and that the inventor of the present invention may appropriately define and use the concepts of various terms to best describe their invention, and furthermore, that these terms and words should be interpreted in a meaning and concept consistent with the technical spirit of the present invention.

[0056] In other words, it should be understood that the terms used in this specification are used merely to describe preferred embodiments of the present invention and are not intended to specifically limit the content of the present invention, and that these terms are defined in consideration of the various possibilities of the present invention.

[0057] In addition, it should be noted that in this specification, singular expressions may include plural expressions unless the context clearly indicates a different meaning, and that even if they are expressed in a similarly plural form, they may include the meaning of the singular.

[0058] Throughout this specification, where it is stated that a component "includes" another component, unless specifically stated otherwise, this may mean that it does not exclude any other component but may include any other component.

[0059] In addition, in the following description of the present invention, detailed descriptions of components that are deemed to unnecessarily obscure the essence of the present invention, such as known technologies including prior art, may be omitted.

[0060]

[0061] FIG. 1 is a process diagram showing a method for manufacturing a composite cathode for an all-solid-state battery according to the present invention.

[0062] As illustrated in FIG. 1, a method for manufacturing a composite cathode for an all-solid-state battery is,

[0063] (a) a step of mixing a coating solution and positive active material particles to coat the surface of the positive active material particles with lithium niobate (LiNbO3);

[0064] (b) a step of preparing a polymer solution by adding a polycarbonate-based polymer and a lithium salt to an organic solvent;

[0065] (c) a step of preparing a mixture by mixing the above-mentioned coated positive active material particles, a sulfide solid electrolyte, and a conductive material; and

[0066] (d) a step of mixing the above mixture and the above polymer solution, heating, and then obtaining a composite anode; is included.

[0067] The following explains the steps in detail.

[0068]

[0069] (a) A step of mixing a coating solution with positive active material particles to coat the surface of the positive active material particles with lithium niobate (LiNbO3).

[0070] Lithium niobate can be coated on the surface of the positive active material particles by mixing the coating solution of the present invention with the positive active material particles.

[0071] Coating part or all of the surface of the positive active material particles with lithium niobate, an ion-conductive inorganic material, prevents direct contact between the positive active material and the sulfide solid electrolyte, thereby having the advantage of enhancing chemical and electrochemical stability.

[0072] The above-mentioned positive electrode active material particles may be lithium transition metal oxides. For example, the lithium transition metal oxide may be lithium nickel cobalt aluminum oxide (NCA) or lithium nickel cobalt manganese oxide (NCM).

[0073] After step (a) above, the weight ratio of the positive active material particles to the lithium niobate coating layer may be 100:0.1 to 100:0.5.

[0074] Here, when the weight ratio of the positive active material particles to the lithium niobate coating layer is within the above range, side reactions occurring at the interface between the positive active material particles and the sulfide solid electrolyte can be suppressed and the interfacial resistance lowered to improve electrochemical stability, organic polymer materials can be well disposed on the surface of the positive active material particles in a subsequent process, and performance degradation due to volume changes of the positive active material occurring during the charge-discharge process can be suppressed to improve charge-discharge cycle life characteristics.

[0075] The above coating solution may use any one of water, ethanol, or isopropanol (IPA) as a solvent, and in a specific example, it may be ethanol.

[0076] The above coating solution can be formed by selecting one of lithium metal and niobium ethoxide (Nb(OC2H5)5), niobium oxalate (Nb2(C2O4)5), niobium pentachloride (NbCl5), ammonium niobate ((NH4)3NbO4), niobium tartrate (Nb(C4H4O6)5), niobium pentafluoride (NbF5), and niobium isopropoxide (Nb(OiPr)5) and adding them to the solvent, and in a specific example, it may be lithium metal and niobium ethoxide.

[0077]

[0078] (b) A step of preparing a polymer solution by adding a polycarbonate-based polymer and a lithium salt to an organic solvent.

[0079] The present invention can prepare a polymer solution by introducing a polycarbonate-based polymer and a lithium salt into an organic solvent.

[0080] Polycarbonate is a resin made by polymerizing carbonates, and it is a thermoplastic plastic made by linking bisphenol A with carbonate bonds.

[0081] Polycarbonate-based polymers have several advantages when used to coat the surface of positive electrode active material particles.

[0082] First, when a polycarbonate-based polymer is used to coat the surface of the positive electrode active material particles, side reactions occurring at the interface between the positive electrode active material particles and the sulfide solid electrolyte can be suppressed and the interfacial resistance lowered, thereby ensuring a smooth ion conduction path.

[0083] Second, electrochemical stability can be improved by placing a polycarbonate-based polymer on the surface of the positive active material particles.

[0084] Third, the flexibility of the composite cathode of the all-solid-state battery is improved, so that it absorbs stress on volume change of the cathode active material during the charge-discharge process, thereby improving the capacity retention rate in charge-discharge cycle behavior and exhibiting excellent efficiency with stable characteristics even at high rate limits.

[0085] The above polycarbonate-based polymer may be one or more selected from the group consisting of polypropylene carbonate, polydimethyl carbonate, polydiethyl carbonate, polydipropyl carbonate, polyethylmethyl carbonate, polymethylpropyl carbonate, polyethylpropyl polycarbonate, and polyethylene carbonate, and preferably may be polypropylene carbonate (PPC), but is not limited thereto.

[0086] The above lithium salts include lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium hexafluorophosphate (LiPF6), lithium hexafluoroantimonate (LiSbF6), lithium hexafluoroarsenate (LiAsF6), lithium difluoromethane sulfonate (LiC4F9SO3), lithium perchlorate (LiClO4), lithium aluminate (LiAlO2), lithium tetrachloroaluminate (LiAlCl4), lithium chloride (LiCl), and lithium iodide, It may be one or more selected from the group consisting of LiI), preferably lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), but is not limited thereto.

[0087] Here, when lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) is used as the lithium salt, it can form a solid electrolyte interface stably with high electrochemical stability and excellent solubility.

[0088] The molar ratio of the polycarbonate-based polymer and the lithium salt may be 1:1 to 30:1, for example, 5:1 to 15:1.

[0089] Here, when the molar ratio of the polycarbonate-based polymer and the lithium salt is within the above range, the lithium ion transfer characteristics are good.

[0090] If the above molar ratio is less than 1:1, there is a problem that the amount of lithium salt is excessive and precipitates, and if it exceeds 30:1, there is a problem that the ionic conductivity is too low.

[0091] The above organic solvent may be a diethyl carbonate solvent, but is not limited thereto.

[0092] Here, it is preferable to use the organic solvent in an amount equal to four times the weight sum of the polycarbonate-based polymer and the lithium salt.

[0093]

[0094] (c) A step of preparing a mixture by mixing coated positive active material particles, a sulfide solid electrolyte, and a conductive material.

[0095] The present invention can prepare a mixture by mixing lithium niobate-coated positive active material particles, a sulfide solid electrolyte, and a conductive material through the preceding process.

[0096] The above sulfide solid electrolyte is Li6PS5Cl, Li6PS5, Li7P3S 11 , Li3PS4, Li 10 GeP2S 12 , Li3PO4-Li2S-Si2S, Li2S-SiS2, LiI-Li2S-P2S5, Li2S-P2S5, LiI-Li3PO4-P2S5, LiI-Li2S-B2S3, Li3PO4-Li2S-SiS2, LiPO4-Li2S-SiS, LiI-Li2S-P2O5, LiI-Li2S-SiS2, Li2S-P2S5-LiCl, Li7P3S 11 It may be one or more selected from the group consisting of, preferably, argyrodite (Li6PS5Cl), but is not limited thereto.

[0097] Argyrodite type (argyrodite, Li7-x PS 6-x Cl x Argyrodite is a lithium phosphorus sulfide and has a three-dimensional crystal structure composed of sulfur (S), lithium (Li), and phosphorus (P) atoms. Argyrodite has high conductivity and can be used as a raw material for electrolytes. In addition, it has high chemical stability and can be used as a raw material for the electrolyte of chemically stable all-solid-state batteries.

[0098] The above conductive material may be one or more selected from the group consisting of carbon nanofibers, carbon nanotubes, and carbon black, and preferably may be carbon nanofibers, but is not limited thereto.

[0099] Conductive materials are substances that enable electrons released by the positive active material in a battery to flow smoothly to the lithium metal anode. In other words, they stabilize chemical reactions within the all-solid-state battery, thereby improving efficiency.

[0100] The above-mentioned carbon nanofiber can be used as the composite cathode material of the present invention. By utilizing the high specific surface area of ​​the carbon nanofiber, it can be used as a composite cathode material in a small amount, thereby securing high capacity characteristics relative to the electrode weight. Furthermore, the short diffusion distance between lithium ions and the composite cathode material provides strengths in charge-discharge performance at high speeds, and there is also the advantage that electrons generated on the surface can efficiently move through the carbon nanofibers present inside.

[0101] The carbon nanotubes mentioned above possess high electrical conductivity, thermal conductivity, and a large surface area. Due to this, they can be used to improve the charge-discharge cycle life characteristics of all-solid-state batteries.

[0102] The above carbon black is composed of carbon powder and has excellent electrical conductivity and durability, so it can be used to improve the ion conductivity of all-solid-state batteries.

[0103] In step (c) above, the total composition may consist of 60 to 95 weight% coated positive active material particles, 4 to 37 weight% sulfide solid electrolyte, and 1 to 10 weight% conductive material. When the coated positive active material particles, sulfide solid electrolyte, and conductive material are in the above weight ratios relative to the total composition, the ion conductivity and electron transfer characteristics are good, the interfacial resistance is lowered, the capacity retention rate is improved, and the characteristics are stable even at high rate limits.

[0104] If the above weight ratio is deviated from, the ion conductivity and electron transfer characteristics are degraded, the interfacial resistance increases, the capacity retention rate decreases, and the charge / discharge cycle behavior at high rate speeds may not be stabilized.

[0105]

[0106] (d) A step of mixing the mixture and the polymer solution, heating, and then obtaining a composite anode

[0107] The present invention allows for obtaining a composite cathode by mixing a mixture of lithium niobate-coated cathode active material particles, a sulfide solid electrolyte, and a conductive material from the preceding process with a polymer solution prepared by adding a polycarbonate-based polymer and a lithium salt to an organic solvent, and then heating the mixture.

[0108] A composite anode refers to an anode electrode composed of two or more chemical components. Composite anodes are manufactured by mixing various materials. Since the materials used in the manufacture of composite anodes have different electrochemical properties, the electrochemical properties of the composite anode can be controlled by mixing these materials.

[0109] Preferably, the mixture constituting the composite anode and the polymer solution must be uniformly mixed. If they are not uniformly mixed, the electrochemical reaction will be insufficient, which may lead to a degradation of the performance of the all-solid-state battery.

[0110] In step (d) above, the mixture and the polymer solution can be sequentially mixed in a weight ratio of 100:10 to 15.

[0111] Here, when the mixing ratio of the mixture and the polymer solution is within the above range, the organic polymer material can be well disposed on the surface of the positive electrode active material particles, and side reactions occurring at the interface between the positive electrode active material particles and the sulfide solid electrolyte can be suppressed and the interfacial resistance can be lowered to improve electrochemical stability, and performance degradation due to volume change of the positive electrode active material during the charge-discharge process can be suppressed to improve charge-discharge cycle life characteristics.

[0112] After mixing the above mixture and the above polymer solution, the solvent used in the preceding process can be removed by heating, and the heating can be performed at 150°C for 3 hours, but is not limited thereto.

[0113] A composite anode is obtained through the above-described method.

[0114] The above composite cathode may have a weight ratio of cathode active material particles to a lithium niobate coating layer of 100:0.1 to 100:0.5.

[0115] In the above composite anode, a polycarbonate-based polymer may be disposed on a portion of the surface of the anode active material particles.

[0116] The composite cathode of the present invention is applicable to all-solid-state batteries, and the all-solid-state battery to which the composite cathode is applied has the effect of lowering interfacial resistance, having excellent ion conductivity and chemical stability, improving capacity retention rate when charge-discharge cycles are repeated, and having stable characteristics even at high rate rates.

[0117] Hereinafter, in order to specifically explain the present invention, it will be described in detail with reference to examples.

[0118]

[0119] <Example>

[0120] <Example 1> Manufacturing of a Composite Cathode-Based All-Solid State Battery

[0121] 1) A counter electrode was manufactured by placing a SUS (STEEL USE STAINLESS) film current collector, which is a current collector, into a mold made of Teflon material, and placing a lithium metal film with a thickness of 20 μm and an indium film with a thickness of 50 μm on top of it.

[0122] 2) 150 mg of argyrodite sulfide solid electrolyte having an average diameter of 5 μm was uniformly coated onto the counter electrode and then a pressure of about 100 MPa was applied.

[0123] 3) A positive active material, NCA (Nickel Cobalt Aluminum), was added to a solution of lithium metal, niobium ethoxide, and ethanol, stirred, and dried to prepare a positive active material coated with 0.5% by weight of lithium niobate.

[0124] 4) A polypropylene carbonate (PPC) polymer and a lithium bis(trifluoromethanesulfonyl)imide lithium salt were mixed in a molar ratio of 10:1, and a polypropylene carbonate polymer solution was prepared using diethyl carbonate as a solvent. The solvent was added in an amount equal to four times the weight of the polypropylene carbonate polymer and the lithium bis(trifluoromethanesulfonyl)imide lithium salt.

[0125] 5) A mixture was prepared by uniformly mixing a lithium niobate-coated NCA (Nickel Cobalt Aluminum) cathode active material, an argyrodite-based sulfide solid electrolyte, and carbon nanofibers in a weight ratio of 75:22:3.

[0126] 6) The polypropylene carbonate-based polymer solution was added to the above mixture in a weight ratio of 100:15 (mixture:polypropylene carbonate polymer) and mixed uniformly, and then dried in a vacuum chamber at 150°C for 3 hours to remove the diethyl carbonate used as a solvent to produce a composite anode.

[0127] 7) The above composite anode was uniformly coated onto the pressurized sulfide solid electrolyte, and then a pressure of about 300 MPa was applied to manufacture a sulfide-based all-solid-state battery with a hybrid coating applied to the composite anode.

[0128]

[0129] <Example 2> Manufacture of a Composite Cathode-Based All-Solid State Battery

[0130] 1) A counter electrode was manufactured by placing a SUS film current collector, which is a current collector, into a mold made of Teflon material, and placing a lithium metal film with a thickness of 20 μm and an indium film with a thickness of 50 μm on top of it.

[0131] 2) 150 mg of argyrodite sulfide solid electrolyte with a diameter of 5 μm was uniformly coated onto the counter electrode and then a pressure of about 100 MPa was applied.

[0132] 3) Nickel Cobalt Aluminum (NCA), which is the cathode active material, was added to a solution of lithium metal, niobium ethoxide, and ethanol, stirred, and dried to prepare a cathode active material coated with 0.1% by weight of lithium niobate.

[0133] 4) A polypropylene carbonate polymer solution was prepared by mixing a polypropylene carbonate polymer and a lithium bis(trifluoromethanesulfonyl)imide lithium salt in a molar ratio of 10:1 and using diethyl carbonate as a solvent. The solvent was added in an amount equal to four times the weight of the polypropylene carbonate polymer and the lithium bis(trifluoromethanesulfonyl)imide lithium salt.

[0134] 5) A mixture was prepared by uniformly mixing a lithium niobate-coated NCA (Nickel Cobalt Aluminum) cathode active material, an argyrodite-based sulfide solid electrolyte, and carbon nanofibers in a weight ratio of 75:22:3.

[0135] 6) The polypropylene carbonate-based polymer solution was added to the above mixture in a weight ratio of 100:15 (mixture:polypropylene carbonate polymer) and mixed uniformly, and then dried in a vacuum chamber at 150°C for 3 hours to remove the diethyl carbonate used as a solvent to produce a composite anode.

[0136] 7) The above composite anode was uniformly coated onto the pressurized sulfide solid electrolyte, and then a pressure of about 300 MPa was applied to manufacture a sulfide-based all-solid-state battery with a hybrid coating applied to the composite anode.

[0137]

[0138] <Example 3> Manufacturing of a Composite Cathode-Based All-Solid State Battery

[0139] 1) A counter electrode was manufactured by placing a SUS film current collector, which is a current collector, into a mold made of Teflon material, and placing a lithium metal film with a thickness of 20 μm and an indium film with a thickness of 50 μm on top of it.

[0140] 2) 150 mg of argyrodite sulfide solid electrolyte with a diameter of 5 μm was uniformly coated onto the counter electrode and then a pressure of about 100 MPa was applied.

[0141] 3) A positive active material, NCA (Nickel Cobalt Aluminum), was added to a solution of lithium metal, niobium ethoxide, and ethanol, stirred, and dried to prepare a positive active material coated with 0.1% by weight of lithium niobate.

[0142] 4) A polypropylene carbonate polymer solution was prepared by mixing a polypropylene carbonate polymer and a lithium bis(trifluoromethanesulfonyl)imide lithium salt in a molar ratio of 10:1 and using diethyl carbonate as a solvent. The solvent was added in an amount equal to four times the weight sum of the polypropylene carbonate polymer and the lithium bis(trifluoromethanesulfonyl)imide lithium salt.

[0143] 5) A mixture was prepared by uniformly mixing a lithium niobate-coated NCA (Nickel Cobalt Aluminum) cathode active material, an argyrodite-based sulfide solid electrolyte, and carbon nanofibers in a weight ratio of 75:22:3.

[0144] 6) The polypropylene carbonate-based polymer solution was added to the above mixture in a weight ratio of 100:10 (mixture:polypropylene carbonate polymer) and mixed uniformly, and then dried in a vacuum chamber at 150°C for 3 hours to remove the diethyl carbonate used as a solvent to produce a composite anode.

[0145] 7) The above composite anode was uniformly coated onto the pressurized sulfide solid electrolyte, and then a pressure of about 300 MPa was applied to manufacture a sulfide-based all-solid-state battery with a hybrid coating applied to the composite anode.

[0146]

[0147] <Comparative Example 1> Manufacture of an all-solid-state battery not including a hybrid coating

[0148] 1) A counter electrode was manufactured by placing a SUS film current collector, which is a current collector, into a mold made of Teflon material, and placing a lithium metal film with a thickness of 20 μm and an indium film with a thickness of 50 μm on top of it.

[0149] 2) 150 mg of argyrodite sulfide solid electrolyte with a diameter of 5 μm was uniformly coated onto the counter electrode and then a pressure of about 100 MPa was applied.

[0150] 3) A composite cathode was prepared by uniformly mixing NCA (Nickel Cobalt Aluminum), an argyrodite sulfide solid electrolyte, and carbon nanofibers in a weight ratio of 75:22:3.

[0151] 4) After uniformly coating the above composite anode onto the above pressurized sulfide solid electrolyte, a pressure of about 300 MPa was applied to manufacture a sulfide-based all-solid-state battery that does not include a hybrid coating.

[0152]

[0153] <Evaluation Example>

[0154] <Evaluation Example 1> Resistance Evaluation of All-Solid State Battery Composite Cathode

[0155] The resistance of an all-solid-state battery containing a composite cathode without the hybrid coating of Comparative Example 1 and an all-solid-state battery containing a composite cathode with the hybrid coating of Example 3 was measured at 28°C in the range of 1.0 MHz to 10 mHz over time.

[0156] Figure 2 is a graph of resistance over time of an all-solid-state battery including the composite cathode of Comparative Example 1 of the present invention.

[0157] Figure 3 is a graph of the resistance over time of an all-solid-state battery including the composite anode of Example 3 of the present invention.

[0158] As shown in FIGS. 2 and 3, in the case of the all-solid-state battery containing the composite cathode of Comparative Example 1, the resistance value increased significantly over time, rising from an initial value of approximately 200 Ω to approximately 550 Ω after 112 hours; however, in the case of the all-solid-state battery containing the composite cathode of Example 3, the resistance value did not increase significantly over time, showing a similar value of approximately 230 Ω after 112 hours, rising from an initial value of approximately 200 Ω. Through this, it can be confirmed that the composite cathode with the hybrid coating of Example 3 has lower resistance and exhibits superior characteristics in terms of chemical stability compared to the composite cathode without the hybrid coating of Comparative Example 1.

[0159]

[0160] <Evaluation Example 2> Evaluation of rate capability characteristics of an all-solid-state battery containing the composite cathode of Comparative Example 1

[0161] The charge / discharge capacity of an all-solid-state battery containing the composite cathode of Comparative Example 1 was measured according to rate speed at 28°C in a limited range of 2.0 V to 3.7 V (cut-off potential vs. Li / In).

[0162] The rate capability of the all-solid-state battery containing the composite cathode of Comparative Example 1 was evaluated in the order of 0.1C, 0.2C, 0.5C, 1.0C, and 0.1C.

[0163] Figure 4 is a graph showing the results of evaluating the rate capability of an all-solid-state battery including the composite cathode of Comparative Example 1 of the present invention.

[0164] As shown in Fig. 4, it can be confirmed that in the all-solid-state battery containing the composite cathode of Comparative Example 1, the initial capacity was high, but as the rate speed increased, the capacity became low and unstable.

[0165]

[0166] <Evaluation Example 3> Evaluation of rate capability characteristics of an all-solid-state battery containing the composite cathode of Example 1

[0167] The charge / discharge capacity of an all-solid-state battery containing the composite cathode of Example 1 was measured according to rate speed at 28°C in a limited range of 2.0 V to 3.7 V (cut-off potential vs. Li / In).

[0168] The rate capability of the all-solid-state battery containing the composite cathode of Example 1 was evaluated in the order of 0.1C, 0.2C, 0.5C, 1.0C, and 0.1C.

[0169] Figure 5 is a graph showing the results of evaluating the rate capability of an all-solid-state battery including the composite cathode of Example 1 of the present invention.

[0170] As shown in Fig. 5, it can be seen that the initial capacity is relatively low and, while superior to Comparative Example 1 at a high rate, it exhibits somewhat unstable capacity characteristics and low stability.

[0171]

[0172] <Evaluation Example 4> Evaluation of rate capability characteristics of an all-solid-state battery containing the composite cathode of Example 2

[0173] The charge / discharge capacity of an all-solid-state battery containing the composite cathode of Example 2 was measured according to rate speed at 28°C in a limited range of 2.0 V to 3.7 V (cut-off potential vs. Li / In).

[0174] The rate capability of the all-solid-state battery containing the composite cathode of Example 2 was evaluated in the order of 0.1C, 0.2C, 0.5C, 1.0C, and 0.1C.

[0175] Figure 6 is a graph showing the results of evaluating the rate capability of an all-solid-state battery including the composite cathode of Example 2 of the present invention.

[0176] As shown in Fig. 6, it can be confirmed that although the initial capacity is relatively low, it exhibits more stable characteristics than Example 1 and Comparative Example 1 even at high rate speeds.

[0177]

[0178] <Evaluation Example 5> Evaluation of rate capability characteristics of an all-solid-state battery containing the composite cathode of Example 3

[0179] The charge / discharge capacity of an all-solid-state battery containing the composite cathode of Example 3 was measured according to rate speed at 28°C in a limited range of 2.0 V to 3.7 V (cut-off potential vs. Li / In).

[0180] The rate capability of the all-solid-state battery containing the composite cathode of Example 3 was evaluated in the order of 0.1C, 0.2C, 0.5C, 1.0C, and 0.1C.

[0181] Figure 7 is a graph showing the results of evaluating the rate capability of an all-solid-state battery including the composite cathode of Example 3 of the present invention.

[0182] As shown in Fig. 7, the initial capacity is excellent, and even at high rate speeds, it exhibits a higher capacity than Example 1, Example 2 and Comparative Example 1 and demonstrates excellent stability.

[0183]

[0184] <Evaluation Example 6> Comparison of Rate Capability Characteristics of All-Solid State Batteries According to the Type of Composite Anode

[0185] The charge / discharge capacity of an all-solid-state battery containing a composite cathode according to Comparative Example 1, Example 1, Example 2, and Example 3 was measured according to rate speed at 28°C in a limited range of 2.0 V to 3.7 V (cut-off potential vs. Li / In).

[0186] The rate capability of all-solid-state batteries containing composite cathodes according to Comparative Example 1, Example 1, Example 2, and Example 3 was evaluated and compared in the order of 0.1C, 0.2C, 0.5C, 1.0C, and 0.1C.

[0187] FIG. 8 is a graph comparing the discharge capacity of the rate capability characteristics of all-solid-state batteries including the composite cathodes of Comparative Example 1, Example 1, Example 2, and Example 3 of the present invention.

[0188] As shown in Fig. 8, Comparative Example 1 exhibited the highest initial capacity but showed very low capacity and stability when evaluated at high rate speeds. On the other hand, Examples 1 and 2 had low initial capacities but exhibited relatively superior characteristics compared to Comparative Example 1 at high rate speeds. Example 3 showed a high initial capacity, the highest capacity even at high rate speeds, and the best stability.

[0189]

[0190] <Evaluation Example 7> Evaluation of cycle characteristics of an all-solid-state battery containing the composite cathode of Comparative Example 1

[0191] The cycle characteristics of an all-solid-state battery containing the composite cathode of Comparative Example 1 were measured up to 100 cycles at a rate of 0.3 C at 28°C with a cut-off potential of 2.0 V to 3.7 V.

[0192] FIG. 9 is a graph showing the results of evaluating the cycle characteristics of an all-solid-state battery including the composite cathode of Comparative Example 1 of the present invention. The results are as shown in [Table 1] below.

[0193] Performance Figures Initial Capacity (mAh / g) 145 Discharge Capacity after 100 Cycles (mAh / g) 53 Capacity Retention Rate (%) 36

[0194]

[0195] Referring to Figure 9 and Table 1, the all-solid-state battery containing the composite cathode of Comparative Example 1 showed a discharge capacity of 145 mAh / g after the first cycle, but the capacity decreased rapidly, and the discharge capacity decreased to 53 mAh / g after 100 cycles, confirming that the cycle stability is very low with a capacity retention rate of 36%.

[0196]

[0197] <Evaluation Example 8> Evaluation of cycle characteristics of an all-solid-state battery containing the composite cathode of Example 1

[0198] The cycle characteristics of an all-solid-state battery containing the composite cathode of Example 1 were measured up to 100 cycles at a rate of 0.3 C at 28°C with a cut-off potential of 2.0 V to 3.7 V.

[0199] FIG. 10 is a graph showing the results of evaluating the cycle characteristics of an all-solid-state battery including the composite cathode of Example 1 of the present invention. The results are as shown in [Table 2] below.

[0200] Performance Figures Initial Capacity (mAh / g) 137 Discharge Capacity after 100 Cycles (mAh / g) 94 Capacity Retention Rate (%) 69

[0201]

[0202] Referring to Figure 10 and Table 2, the all-solid-state battery containing the composite cathode of Example 1 showed a slightly lower discharge capacity of 137 mAh / g after the first cycle, and the discharge capacity decreased to 94 mAh / g after 100 cycles, resulting in a capacity retention rate of 69%, which confirms that the cycle stability is improved compared to Comparative Example 1.

[0203]

[0204] <Evaluation Example 9> Evaluation of cycle characteristics of an all-solid-state battery containing the composite cathode of Example 2

[0205] The cycle characteristics of an all-solid-state battery containing the composite cathode of Example 2 were measured up to 100 cycles at a rate of 0.3 C at 28°C with a cut-off potential of 2.0 V to 3.7 V.

[0206] FIG. 11 is a graph showing the results of evaluating the cycle characteristics of an all-solid-state battery including the composite cathode of Example 2 of the present invention. The results are as shown in [Table 3] below.

[0207] Performance Figures Initial Capacity (mAh / g) 156 Discharge Capacity after 100 Cycles (mAh / g) 104 Capacity Retention Rate (%) 67

[0208]

[0209] Referring to Figure 11 and Table 3, the all-solid-state battery containing the composite cathode of Example 2 showed a relatively high discharge capacity of 156 mAh / g after the first cycle, but the capacity decreased rapidly, and the discharge capacity decreased to 104 mAh / g after 100 cycles, resulting in a capacity retention rate of 67%, which is an improvement in cycle efficiency compared to Comparative Example 1.

[0210]

[0211] <Evaluation Example 10> Evaluation of cycle characteristics of an all-solid-state battery containing the composite cathode of Example 3

[0212] The cycle characteristics of an all-solid-state battery containing the composite cathode of Example 3 were measured up to 100 cycles at a rate of 0.3 C at 28°C with a cut-off potential of 2.0 V to 3.7 V.

[0213] FIG. 12 is a graph showing the results of evaluating the cycle characteristics of an all-solid-state battery including the composite cathode of Example 3 of the present invention. The results are as shown in [Table 4] below.

[0214] Performance Figures Initial Capacity (mAh / g) 15 Discharge Capacity after 100 Cycles (mAh / g) 126 Capacity Retention Rate (%) 83

[0215]

[0216] Referring to Figure 12 and Table 4, the all-solid-state battery containing the composite cathode of Example 3 showed a relatively high discharge capacity of 151 mAh / g after the first cycle, and after 100 cycles, the discharge capacity decreased to 126 mAh / g, resulting in a capacity retention rate of 83%. It can be confirmed that the cycle characteristics were excellent and the efficiency was also excellent.

[0217]

[0218] <Evaluation Example 11> Comparison of Cycle Characteristics of All-Solid State Batteries According to the Type of Composite Anode

[0219] The cycle characteristics of all-solid-state batteries containing the composite cathodes of Comparative Example 1, Example 1, Example 2, and Example 3 were evaluated and compared up to 100 cycles at a rate of 0.3 C at 28°C and a limiting range of 2.0 V to 3.7 V (cut-off potential vs. Li / In).

[0220] FIG. 13 is a graph comparing the discharge capacity of the cycle characteristics of all-solid-state batteries including the composite cathodes of Comparative Example 1, Example 1, Example 2, and Example 3 of the present invention.

[0221] FIG. 14 is a graph comparing the capacity retention rate of the cycle characteristics of all-solid-state batteries including the composite cathodes of Comparative Example 1, Example 1, Example 2, and Example 3 of the present invention. The results are as shown in [Table 5] below.

[0222] Comparative Example 1 Example 1 Example 2 Example 3 Initial Capacity (mAh / g) 145 137 156 151 100 Discharge Capacity (mAh / g) 539 410 4126 Capacity Retention Rate (%) 366 69 6783

[0223]

[0224] Referring to FIG. 13 and Table 5, the all-solid-state battery containing the composite cathode of Example 3 showed a relatively high discharge capacity of 151 mAh / g after the first cycle, and the capacity decrease was small, dropping to 126 mAh / g after 100 cycles. Compared to Comparative Example 1, both the initial capacity and the capacity after 100 cycles showed higher values, confirming that the initial capacity and cycle characteristics are excellent. In the case of Examples 1 and 2, it can also be confirmed that the cycle characteristics were improved compared to Comparative Example 1.

[0225] Referring to Figure 14 and Table 5, it can be seen that the capacity retention rate of the all-solid-state battery containing the composite cathode of Example 1 is 69%, the capacity retention rate of the all-solid-state battery containing the composite cathode of Example 2 is 67%, and the capacity retention rate of the all-solid-state battery containing the composite cathode of Example 3 is 83%, which is an improvement over the capacity retention rate of 36% of the all-solid-state battery containing the composite cathode of Comparative Example 1, showing superior cycle characteristics and efficiency.

[0226]

[0227] Although various preferred embodiments of the present invention have been described above with some examples, the descriptions of various embodiments described in the "Specific details for carrying out the invention" section are merely illustrative, and those skilled in the art to which the present invention pertains will understand that the present invention can be carried out with various modifications or equivalent embodiments from the above description.

[0228] In addition, since the present invention can be implemented in various other forms, the present invention is not limited by the description above. The above description is provided merely to make the disclosure of the present invention complete and to fully inform those skilled in the art of the scope of the present invention, and it should be understood that the present invention is defined only by each claim of the claims.

[0229] According to the present invention, a method for manufacturing a composite cathode for an all-solid-state battery is provided, wherein a hybrid material of an inorganic material and an organic polymer material is coated onto cathode active material particles to suppress side reactions occurring at the interface with a sulfide solid electrolyte and to lower interfacial resistance, thereby improving electrochemical stability.

[0230] In addition, the present invention provides a method for manufacturing a composite cathode for an all-solid-state battery that suppresses performance degradation of the composite cathode caused by volume change of the cathode active material during the charging and discharging process and improves charge-discharge cycle life characteristics.

[0231] In addition, according to the present invention, a composite cathode for an all-solid-state battery is provided, in which a hybrid material of an inorganic material and an organic polymer material is coated onto cathode active material particles to suppress side reactions occurring at the interface with a sulfide solid electrolyte and lower interfacial resistance, thereby improving electrochemical stability.

[0232] In addition, the present invention provides a composite cathode for an all-solid-state battery that suppresses performance degradation of the composite cathode caused by volume change of the cathode active material during the charging and discharging process and improves charge-discharge cycle life characteristics.

[0233] In addition, we provide an all-solid-state battery with excellent efficiency that has improved capacity retention rate in charge-discharge cycle behavior and stable characteristics even at high rate rates.

Claims

1. (a) A step of mixing a coating solution and positive active material particles to coat the surface of the positive active material particles with lithium niobate (LiNbO3); (b) a step of preparing a polymer solution by adding a polycarbonate-based polymer and a lithium salt to an organic solvent; (c) a step of preparing a mixture by mixing the above-mentioned coated positive active material particles, a sulfide solid electrolyte, and a conductive material; and (d) a step of mixing the above mixture and the above polymer solution, heating, and then obtaining a composite anode; comprising, Method for manufacturing a composite cathode for all-solid-state batteries.

2. In Paragraph 1, The above positive active material particles are characterized as being lithium transition metal oxides, Method for manufacturing a composite cathode for all-solid-state batteries.

3. In Paragraph 1, Characterized that after step (a) above, the weight ratio of the positive active material particles to the lithium niobate coating layer is 100:0.1 to 100:0.5, Method for manufacturing a composite cathode for all-solid-state batteries.

4. In Paragraph 1, In step (b) above, the polycarbonate-based polymer is characterized by being one or more selected from the group consisting of polypropylene carbonate, polydimethyl carbonate, polydiethyl carbonate, polydipropyl carbonate, polyethylmethyl carbonate, polymethylpropyl carbonate, polyethylpropyl polycarbonate, and polyethylene carbonate. Method for manufacturing a composite cathode for all-solid-state batteries.

5. In Paragraph 1, In step (b) above, the lithium salt is lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium hexafluorophosphate (LiPF6), lithium hexafluoroantimonate (LiSbF6), lithium hexafluoroarsenate (LiAsF6), lithium difluoromethane sulfonate (LiC4F9SO3), lithium perchlorate (LiClO4), lithium aluminate (LiAlO2), lithium tetrachloroaluminate (LiAlCl4), lithium chloride (LiCl), and lithium iodide (lithium Characterized by being one or more selected from the group consisting of iodide, LiI, Method for manufacturing a composite cathode for all-solid-state batteries.

6. In Paragraph 1, Characterized in that, in step (b) above, the molar ratio of the polycarbonate-based polymer and the lithium salt is 5:1 to 15:1, Method for manufacturing a composite cathode for all-solid-state batteries.

7. In Paragraph 1, The organic solvent in step (b) above is characterized as being a diethyl carbonate solvent, Method for manufacturing a composite cathode for all-solid-state batteries.

8. In Paragraph 1, In step (c) above, the sulfide solid electrolyte is Li6PS5Cl, Li6PS5, Li7P3S 11 , Li3PS4, Li 10 GeP2S 12 , Li3PO4-Li2S-Si2S, Li2S-SiS2, LiI-Li2S-P2S5, Li2S-P2S5, LiI-Li3PO4-P2S5, LiI-Li2S-B2S3, Li3PO4-Li2S-SiS2, LiPO4-Li2S-SiS, LiI-Li2S-P2O5, LiI-Li2S-SiS2, Li2S-P2S5-LiCl, Li7P3S 11 Characterized by being one or more selected from a group consisting of Method for manufacturing a composite cathode for all-solid-state batteries.

9. In Paragraph 1, In step (c) above, the conductive material is characterized as being one or more selected from the group consisting of carbon nanofibers, carbon nanotubes, and carbon black. Method for manufacturing a composite cathode for all-solid-state batteries.

10. In Paragraph 1, Characterized in that, with respect to the total composition in step (c) above, the coated positive active material particles comprise 60 to 95 weight%, the sulfide solid electrolyte comprises 4 to 37 weight%, and the conductive material comprises 1 to 10 weight%. Method for manufacturing a composite cathode for all-solid-state batteries.

11. In Paragraph 1, Characterized in that, in step (d) above, the mixture and the polymer solution are sequentially mixed in a weight ratio of 100:10 to 15. Method for manufacturing a composite cathode for all-solid-state batteries.

12. Manufactured by the method of any one of paragraphs 1 to 10, Composite anode.

13. In Paragraph 12, The above composite cathode is characterized by a weight ratio of cathode active material particles to a lithium niobate coating layer of 100:0.1 to 100:0.

5. Composite anode.

14. In Paragraph 12, The above composite anode is characterized by having a polycarbonate-based polymer disposed on a portion of the surface of the anode active material particles. Composite anode.

15. Comprising the composite anode of Paragraph 12, All-solid-state battery.

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