All solid state battery with improved durability and manufacturing method thereof

Abstract

The present invention relates to a novel all-solid-state battery with improved durability and a method for manufacturing the same. Specifically, the all-solid-state battery comprises a positive current collector, a positive active material layer having one surface in contact with a certain area of ​​the positive current collector, a solid electrolyte layer located on the positive active material layer and surrounding the other surface and side of the positive active material layer, a negative electrode layer located on the solid electrolyte layer having an area larger than that of the positive active material layer and smaller than that of the solid electrolyte layer, and a spacer located on the solid electrolyte layer and in contact with the side of the negative electrode layer.

Description

Technology Field

[0001] The present invention relates to a novel all-solid-state battery with improved durability and a method for manufacturing the same. Background Technology

[0002] A typical all-solid-state battery is a three-layer laminate comprising a positive active material layer bonded to a positive current collector, a negative active material layer bonded to a negative current collector, and a solid electrolyte disposed between the positive active material layer and the negative active material layer.

[0003] The above-mentioned negative electrode active material layer includes a solid electrolyte in addition to active materials such as graphite, which is intended to ensure lithium-ion conductivity within the negative electrode active material layer. However, this results in a lower proportion of active material within the negative electrode active material layer, and an increase in volume and weight, thereby reducing the energy density of the all-solid-state battery.

[0004] Research is currently underway on a cathode-free all-solid-state battery designed to increase energy density by eliminating the negative electrode and directly depositing lithium ions generated from the positive electrode onto the negative electrode current collector during charging.

[0005] FIG. 1A is a cross-sectional view schematically illustrating a negative electrode all-solid-state battery. The negative electrode all-solid-state battery is an all-solid-state battery in which a positive electrode current collector (91), a positive electrode active material layer (92), a solid electrolyte layer (93), and a negative electrode current collector (94) are stacked in that order. When the negative electrode all-solid-state battery is charged, lithium ions are deposited and stored as lithium metal between the solid electrolyte layer (93) and the negative electrode current collector (94).

[0006] Since all components of an all-solid-state battery are solid, high pressure must be applied to ensure that the interfaces between the components are well formed. When high pressure is applied to a non-anode all-solid-state battery as shown in Fig. 1A, the state shown in Fig. 1B is achieved. Due to the high pressure, the edge portion (A) of the positive active material layer (92) collapses, causing the solid electrolyte layer (93) to collapse, and the positive current collector (91) and negative current collector (94), which are metal thin films, are stretched and bent in the direction in which the pressure is applied. As a result, cracks form in the positive active material layer (92) and the solid electrolyte layer (93), and a short circuit occurs as both current collectors (91, 94) come into contact. Prior art literature

[0007] Korean Patent Publication No. 10-2018-0055086 The problem to be solved

[0008] The present invention aims to solve the aforementioned conventional problems and provides a novel structure of a cathode-free all-solid-state battery with good durability and high energy density.

[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] An all-solid-state battery according to one embodiment of the present invention may include: a positive current collector; a positive active material layer having one surface in contact with a certain area of ​​the positive current collector; a solid electrolyte layer located on the positive active material layer and including a central portion located on the positive active material layer with respect to the stacking direction of the all-solid-state battery and a peripheral portion extending from the central portion to surround the side of the positive active material and in contact with the positive current collector; a negative electrode layer located on the solid electrolyte layer, having an area larger than that of the positive active material layer and smaller than that of the solid electrolyte layer; and a spacer located on the solid electrolyte layer and in contact with the side of the negative electrode layer.

[0011] The area of ​​the solid electrolyte layer may be 1.5 to 2 times larger than the area of ​​the positive active material layer.

[0012] The thickness of the center of the solid electrolyte layer may be 30㎛ to 40㎛.

[0013] The above cathode layer includes a cathode current collector and a coating layer located on the cathode current collector, and the coating layer may be laminated so as to be in contact with the solid electrolyte layer.

[0014] The above coating layer may include a carbon material and a metal material capable of forming an alloy or compound with lithium.

[0015] The above cathode layer may consist solely of a cathode current collector.

[0016] The above cathode layer includes a cathode active material layer and a cathode current collector located on the cathode active material layer, and the cathode active material layer may be laminated so as to be in contact with the solid electrolyte layer.

[0017] The above spacer may have a thickness based on the stacking direction of the all-solid-state battery that is equal to or greater than the thickness of the above negative electrode layer.

[0018] The above spacer may include at least one selected from the group consisting of polyethylene (PE), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), and combinations thereof.

[0019] The above-described all-solid-state battery can satisfy the following Equation 1 for the vertical distance (A) between the side of the positive active material layer and the side of the solid electrolyte layer based on its cross-section; the vertical distance (C) between the side of the center of the solid electrolyte layer and the side of the negative electrode layer; and the vertical distance (B) between the side of the negative electrode layer and the side of the spacer.

[0020] [Mathematical Formula 1]

[0021] A ≤ B + C

[0022] The above all-solid-state battery can satisfy A = B + C.

[0023] The above all-solid-state battery may have a unit cell comprising a positive current collector, a positive active material layer, a solid electrolyte layer, and a negative electrode layer, and may have two or more unit cells stacked.

[0024] A method for manufacturing an all-solid-state battery according to one embodiment of the present invention may include the steps of: forming a positive active material layer with a predetermined area on a positive current collector; forming a solid electrolyte layer on the positive active material layer to surround the positive active material layer; forming a negative electrode layer on the solid electrolyte layer, the negative electrode layer having an area larger than that of the positive active material layer and smaller than that of the solid electrolyte layer; forming a spacer on the solid electrolyte layer to contact the side of the negative electrode layer; and applying pressure in the stacking direction of each component to bond them.

[0025] The above manufacturing method may involve joining each component by applying a pressure of 400 MPa to 800 MPa. Effects of the invention

[0026] According to the present invention, a novel structure of a cathode-free all-solid-state battery with good durability and high energy density can be obtained.

[0027] 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

[0028] FIG. 1a is a cross-sectional view illustrating a conventional all-solid-state battery without a negative electrode. FIG. 1b is a cross-sectional view illustrating the all-solid-state battery of FIG. 1a under high pressure. FIG. 2 is a cross-sectional view illustrating an all-solid-state battery according to one embodiment of the present invention. Figure 3 is a plan view illustrating the solid electrolyte layer of the all-solid-state battery of Figure 2. FIG. 4 is a cross-sectional view illustrating an all-solid-state battery according to another embodiment of the present invention. FIG. 5 is a cross-sectional view illustrating an all-solid-state battery according to another embodiment of the present invention. FIG. 6 is a reference diagram for explaining Equation 1 in an all-solid-state battery according to one embodiment of the present invention. Figure 7a shows the results of analyzing a cross-section of an all-solid-state battery according to a comparative example using a scanning electron microscope (SEM). Figure 7b shows the result of charging and discharging an all-solid-state battery according to a comparative example. Figure 8a is the result of analyzing a cross-section of an all-solid-state battery according to an example using a scanning electron microscope (SEM). Figure 8b is the result of measuring the capacity retention rate of an all-solid-state battery according to an embodiment. Specific details for implementing the invention

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0034] FIG. 2 is a cross-sectional view illustrating an all-solid-state battery according to the present invention. The all-solid-state battery comprises a positive current collector (10), a positive active material layer (20) having one surface in contact with a certain area of ​​the positive current collector (10), a solid electrolyte layer (30) located on the positive active material layer (20) and surrounding the other surface (S1) and side (S2) of the positive active material layer (20), a negative electrode layer (40) located on the solid electrolyte layer (30) having an area larger than that of the positive active material layer (20) and smaller than that of the solid electrolyte layer (30), and a spacer (50) located on the solid electrolyte layer (30) and in contact with the side of the negative electrode layer (40).

[0035] The anode current collector (10) may be a plate-shaped substrate that is electrically conductive. The anode current collector (10) may include an aluminum foil.

[0036] The positive active material layer (20) can be formed with an area smaller than that of the positive current collector (10) and positioned on the positive current collector (10).

[0037] The above positive active material layer (12) may include a positive active material, a solid electrolyte, a conductive material, a binder, etc.

[0038] The above positive active material may be an oxide active material or a sulfide active material.

[0039] The above oxide active materials are LiCoO2, LiMnO2, LiNiO2, LiVO2, Li1 + x Ni1 / 3Co1 / 3Mn1 / Rock salt layer type active materials such as 3O2, LiMn2O4, Li(Ni 0.5 Mn 1.5Spinel-type active materials such as )O4, inverse spinel-type active materials such as LiNiVO4 and LiCoVO4, olivine-type active materials such as LiFePO4, LiMnPO4, LiCoPO4, and LiNiPO4, silicon-containing active materials such as Li2FeSiO4 and 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), Li 1+x Mn 2-x-y M y Spinel-type active material in which a portion of the transition metal is replaced 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 be lithium titanate.

[0040] The above sulfide active material may be copper chevrell, iron sulfide, cobalt sulfide, nickel sulfide, etc.

[0041] The above solid electrolyte may be an oxide solid electrolyte or a sulfide solid electrolyte. However, it may be preferable to use a sulfide-based solid electrolyte with high lithium ion conductivity. The above sulfide-based solid electrolyte is not particularly limited, but includes 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, and 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 It could be the back.

[0042] The above conductive material may be carbon black, conducting graphite, ethylene black, graphene, etc.

[0043] The above binder may be BR (Butadiene rubber), NBR (Nitrile butadiene rubber), HNBR (Hydrogenated nitrile butadiene rubber), PVDF (polyvinylidene difluoride), PTFE (polytetrafluoroethylene), CMC (carboxymethylcellulose), etc.

[0044] FIG. 3 is a plan view of the solid electrolyte layer (30). Referring to FIG. 2 and FIG. 3, the solid electrolyte layer (30) may include a central portion (31) located on the positive active material layer (20) with respect to the stacking direction of the all-solid-state battery, and a peripheral portion (32) extending from the central portion (31) and surrounding the side (S2) of the positive active material while in contact with the positive current collector (10).

[0045] Since the solid electrolyte layer (30) surrounds the positive active material layer (20), when the all-solid-state battery is pressurized to a high pressure, the solid electrolyte layer (30) acts as a buffer layer, thereby minimizing pressure on the edges of the positive active material layer (20). As a result, the structural stability of the all-solid-state battery is improved by the solid electrolyte layer (30).

[0046] The area of ​​the solid electrolyte layer (30) may be 1.5 to 2 times larger than the area of ​​the positive active material. The area of ​​the solid electrolyte layer (30) refers to the area when the solid electrolyte layer (30) is viewed from above as shown in FIG. 3. If the area of ​​the solid electrolyte layer (30) is too large, there will be many peripheral areas (32) that do not play a significant role in the movement of lithium ions, which may increase production costs, and pressure through the peripheral areas (32) may not be properly transmitted to the positive active material (30), so the interface between the solid electrolyte layer (30) and the side (S2) of the positive active material layer (20) may not be formed well.

[0047] Conventional all-solid-state batteries without a negative electrode, such as those in Fig. 1a, are manufactured by forming a solid electrolyte layer (93) on a self-supporting film or release paper and then attaching or transferring it to a negative electrode current collector (94) because there is no negative electrode active material layer. This is because it is difficult to apply it directly to the negative electrode current collector (94) since it is a metal thin film, and it is also impossible to apply it directly to the positive electrode active material layer (92) because its surface area is smaller than that of the solid electrolyte layer (93). When the solid electrolyte layer (93) is formed as a self-supporting film, there must be a support structure inside it, and when it is formed on a release paper, it must have a predetermined thickness to be separated from the release paper without damage, so the thickness of the conventional solid electrolyte layer (93) had to be about 100 μm or more.

[0048] As shown in FIG. 2, the present invention has a novel structure in which a solid electrolyte layer (30) surrounds an anode active material layer (20), so the solid electrolyte layer (30) can be formed by applying it onto the anode active material layer (20) using a method such as a doctor blade. That is, since there is no need to form it on a self-supporting film or release paper, there is no need to make it thick.

[0049] Specifically, the thickness of the center (31) of the solid electrolyte layer (30) may be 30㎛ to 40㎛. Since the thickness of the solid electrolyte layer (30) can be significantly reduced compared to conventional methods, the energy density can be greatly increased.

[0050] The solid electrolyte layer (30) may include 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. The sulfide-based solid electrolyte is not particularly limited, but includes 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 It could be the back.

[0051] According to one embodiment of the present invention, the cathode layer (40) may include a cathode current collector (41) and a coating layer (42) located on the cathode current collector (41) as shown in FIG. 2, and the coating layer (42) may be laminated so as to be in contact with the solid electrolyte layer (30).

[0052] The above-mentioned negative current collector (41) may be a plate-shaped substrate having electrical conductivity. The above-mentioned negative current collector (41) may include at least one selected from the group consisting of nickel (Ni), stainless steel (SUS), and combinations thereof.

[0053] The above-mentioned negative current collector (41) may be a high-density metal thin film with a porosity of less than about 1%.

[0054] The above-mentioned negative current collector (41) may have a thickness of 1 μm to 20 μm, or 5 μm to 15 μm.

[0055] The coating layer (42) is configured to induce lithium ions that have moved from the positive active material layer (20) during charging of the all-solid-state battery, so that they can be uniformly deposited as a charging product on the negative current collector (41).

[0056] The coating layer (42) may include a carbon material and a metal material capable of forming an alloy or compound with lithium.

[0057] The above carbon material may include at least one selected from the group consisting of particulate carbon materials, fibrous carbon materials, and combinations thereof.

[0058] The above particulate carbon material may include at least one selected from the group consisting of carbon black, digraphitizable carbon, nongraphitizable carbon, and combinations thereof. The above particulate carbon material may have a particle diameter of 10 nm to 200 nm.

[0059] In addition, the fibrous carbon material may include at least one selected from the group consisting of carbon nanofibers, carbon nanotubes, vapor-grown carbon fibers, and combinations thereof. The fibrous carbon material may have a fiber cross-sectional diameter of 10 nm to 200 nm.

[0060] The above metal material is not particularly limited, but may include at least one selected from the group consisting of, for example, zinc, germanium, tin, antimony, platinum, gold, bismuth, magnesium, aluminum, silver, and combinations thereof.

[0061] According to another embodiment of the present invention, the cathode layer (40) may consist only of a cathode current collector (41) as shown in FIG. 4. The cathode current collector (41) has been described above and will be omitted below.

[0062] According to another embodiment of the present invention, the cathode layer (40) may comprise a cathode active material layer (43) and a cathode current collector (41) located on the cathode active material layer (43) as shown in FIG. 5, and may be laminated so that the cathode active material layer (43) is in contact with the solid electrolyte layer (30). The novel structure of the all-solid-state battery according to the present invention can be applied not only to a cathode-free all-solid-state battery but also to a general all-solid-state battery containing a cathode active material.

[0063] The above negative electrode active material layer (43) may include a negative electrode active material, a solid electrolyte, a binder, etc.

[0064] The above-mentioned cathode active material is not particularly limited, but may be, for example, a carbon active material or a metal active material.

[0065] 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).

[0066] The above metal active material may be an alloy containing at least one of In, Al, Si, Sn, and elements thereof.

[0067] The above solid electrolyte may be an oxide solid electrolyte or a sulfide solid electrolyte. However, it may be preferable to use a sulfide-based solid electrolyte with high lithium ion conductivity. The above sulfide-based solid electrolyte is not particularly limited, but includes 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, and 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 It could be the back.

[0068] The above binder may be BR (Butadiene rubber), NBR (Nitrile butadiene rubber), HNBR (Hydrogenated nitrile butadiene rubber), PVDF (polyvinylidene difluoride), PTFE (polytetrafluoroethylene), CMC (carboxymethylcellulose), etc.

[0069] The above spacer (50) is configured to be provided in the space formed by the sides of the solid electrolyte layer (30) and the negative electrode layer (40) to ensure the structural stability of the all-solid-state battery.

[0070] The above spacer (50) has a side that is located on the same plane as the side of the solid electrolyte layer (30), and its thickness based on the stacking direction of the all-solid-state battery may be equal to or greater than the thickness of the negative electrode layer (40).

[0071] When the above-mentioned all-solid-state battery is pressurized to a high pressure, the positive current collector (10) and the negative current collector (41), which are metal thin films, are stretched, and their ends come into contact, which may cause a short circuit in the battery. The above-mentioned spacer (50) is intended to prevent this and is positioned on the side to prevent the stretching of the negative current collector (41) due to high pressure.

[0072] The above spacer (50) may include at least one selected from the group consisting of polyethylene (PE), polyethylene naphthalate (PEN), polyethylene terephthalate (PET) and combinations thereof.

[0073] The all-solid-state battery according to the present invention may satisfy the following mathematical formula 1 based on the cross-section as shown in FIG. 6, such that the vertical distance (A) between the side of the positive active material layer (20) and the side of the solid electrolyte layer (30), the vertical distance (C) between the side of the center (31) of the solid electrolyte layer and the side of the negative electrode layer (40), and the vertical distance (B) between the side of the negative electrode layer (40) and the side of the spacer (50).

[0074] [Mathematical Formula 1]

[0075] A ≤ B + C

[0076] Here, "vertical distance" refers to the distance at which, when a point on the side of one configuration is connected to a point on the side of another configuration, the connecting line forms a right angle with respect to the cross-section of the all-solid-state battery.

[0077] In addition, "cross-section of an all-solid-state battery" refers to a cross-section in a direction parallel to the stacking direction of the all-solid-state battery.

[0078] The above all-solid-state battery may preferably satisfy A = B + C.

[0079] The all-solid-state battery according to the present invention may have a unit cell in which the positive current collector (10), positive active material layer (20), solid electrolyte layer (30), negative electrode layer (40), and spacer (50) constitute a unit cell, and two or more unit cells may be stacked.

[0080] The stacking method of the above unit cells is not particularly limited and can be stacked in a monopolar or bipolar structure. Accordingly, the height of the spacer (50) can be appropriately adjusted.

[0081] A method for manufacturing an all-solid-state battery according to the present invention may include the steps of forming a positive active material layer of a certain area on a positive current collector, forming a solid electrolyte layer on the positive active material layer to surround the positive active material layer, forming a spacer on the solid electrolyte layer, forming a negative electrode layer in the space formed by the solid electrolyte layer and the spacer, and bonding by applying a pressure of 400 MPa to 800 MPa in the stacking direction of each component.

[0083] Other forms of the present invention will be described in more detail through the following examples. The following examples are merely illustrative to aid in understanding the present invention and do not limit the scope of the present invention.

[0085] Comparative example

[0086] After manufacturing a conventional all-solid-state battery as shown in Fig. 1a, a pressure of about 450 MPa was applied in the stacking direction to bond them.

[0087] Figure 7a shows the results of analyzing the cross-section of an all-solid-state battery according to a comparative example using a scanning electron microscope (SEM). Referring to this, it can be seen that very large cracks have formed in the cathode and electrolyte.

[0088] Figure 7b shows the results of charging and discharging an all-solid-state battery according to a comparative example. Referring to this, it can be seen that a short circuit occurred during the first cycle of charging.

[0090] Examples

[0091] After manufacturing an all-solid-state battery according to the present invention as shown in Fig. 2, a pressure of about 450 MPa was applied in the stacking direction to bond them.

[0092] Figure 8a shows the results of analyzing a cross-section of an all-solid-state battery according to an embodiment using a scanning electron microscope (SEM). Referring to this, it can be seen that no cracks occurred in the anode and electrolyte. In particular, it is very impressive that the edges of the anode did not collapse and properly formed an interface with the electrolyte even when high pressure was applied.

[0093] Figure 8b shows the results of measuring the capacity retention rate of an all-solid-state battery according to an embodiment. Referring to this, the all-solid-state battery according to the embodiment showed a very stable performance with a capacity retention rate of 75% or higher when charging and discharging was performed 50 or more times.

[0095] As the experimental examples and embodiments of the present invention have been described in detail above, the scope of the present invention is not limited to the aforementioned experimental examples and embodiments, 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

[0096] 10: Positive current collector 20: Positive active material layer 30: Solid electrolyte layer 31: Center 32: Periphery 40: Cathode layer 41: Cathode current collector 42: Coating layer 43: Cathode active material layer 50: Spacer

Claims

Claim 1 A positive current collector; a positive active material layer having one surface in contact with a certain area of ​​the positive current collector; a solid electrolyte layer located on the positive active material layer and including a central portion located on the positive active material layer with respect to the stacking direction of the all-solid-state battery and a peripheral portion extending from the central portion, wrapping the side of the positive active material and in contact with the positive current collector; a negative electrode layer located on the solid electrolyte layer, having an area larger than that of the positive active material layer and smaller than that of the solid electrolyte layer; and a spacer located to contact the upper surface of the solid electrolyte layer and in contact with the side of the negative electrode layer, wherein the negative electrode layer includes a negative current collector. Claim 2 An all-solid-state battery according to claim 1, characterized in that the area of ​​the solid electrolyte layer is 1.5 to 2 times larger than the area of ​​the positive electrode active material layer. Claim 3 An all-solid-state battery according to claim 1, characterized in that the thickness of the center of the solid electrolyte layer is 30㎛ to 40㎛. Claim 4 A solid-state battery according to claim 1, wherein the cathode layer comprises a cathode current collector; and a coating layer positioned on the cathode current collector, and the coating layer is laminated to be in contact with the solid electrolyte layer. Claim 5 A solid-state battery according to claim 4, characterized in that the coating layer comprises a carbon material; and a metal material capable of forming an alloy or compound with lithium. Claim 6 A solid-state battery according to claim 1, characterized in that the negative electrode layer is composed solely of a negative electrode current collector. Claim 7 A solid-state battery according to claim 1, wherein the cathode layer comprises a cathode active material layer; and a cathode current collector located on the cathode active material layer, and wherein the cathode active material layer is laminated to be in contact with the solid electrolyte layer. Claim 8 A solid-state battery according to claim 1, characterized in that the thickness of the spacer based on the stacking direction of the solid-state battery is equal to or greater than the thickness of the negative electrode layer. Claim 9 A solid-state battery according to claim 1, characterized in that the spacer comprises at least one selected from the group consisting of polyethylene (PE), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), and combinations thereof. Claim 10 A solid-state battery according to claim 1, characterized in that the vertical distance (A) between the side of the positive active material layer and the side of the solid electrolyte layer based on the cross-section of the solid-state battery; the vertical distance (C) between the side of the center of the solid electrolyte layer and the side of the negative electrode layer; and the vertical distance (B) between the side of the negative electrode layer and the side of the spacer satisfy the following Equation 1. [Equation 1] A ≤ B + C Claim 11 A solid-state battery characterized by satisfying A = B + C in Clause 10. Claim 12 An all-solid-state battery according to claim 1, wherein the positive current collector, positive active material layer, solid electrolyte layer, and negative electrode layer constitute a unit cell, and two or more unit cells are stacked. Claim 13 A method for manufacturing an all-solid-state battery according to any one of claims 1 to 12, comprising: a step of forming a positive active material layer of a certain area on a positive current collector; a step of forming a solid electrolyte layer on the positive active material layer to surround the positive active material layer; a step of forming a negative electrode layer on the solid electrolyte layer, the area of ​​which is larger than that of the positive active material layer and smaller than that of the solid electrolyte layer; a step of forming a spacer positioned to contact the upper surface of the solid electrolyte layer and to contact the side of the negative electrode layer; and a step of bonding by applying pressure in the stacking direction of each component; wherein the negative electrode layer comprises a negative current collector. Claim 14 A method for manufacturing an all-solid-state battery according to claim 13, characterized by bonding by applying a pressure of 400 MPa to 800 MPa.

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