All-solid-state battery including an electrolyte layer having a concave pattern

Abstract

The present invention relates to an anode-free all-solid-state battery. The all-solid-state battery includes a plurality of recesses formed in the electrolyte layer and recessed from the surface of the electrolyte layer in contact with the anode current collector, thereby serving as a space for reversibly depositing lithium.

Description

Technical Field

[0001] The present invention relates to an anode-free all-solid-state battery. The all-solid-state battery may include a plurality of recesses formed to be recessed from one surface of the electrolyte layer, thereby serving as a space for reversible lithium precipitation. Background Art

[0002] Rechargeable secondary batteries are used not only in small electronic devices such as mobile phones and laptop computers, but also in large transportation vehicles such as hybrid vehicles and electric vehicles. Therefore, there is a need to develop secondary batteries with higher stability and energy density.

[0003] Most conventional secondary batteries are configured to form a battery using an organic solvent (organic liquid electrolyte), and thus are limited in terms of improving their stability and energy density.

[0004] Meanwhile, all-solid-state batteries that use an inorganic solid electrolyte instead of an organic solvent have recently received great attention, and thus batteries can be manufactured in a safer and simpler manner.

[0005] However, the problem with all-solid-state batteries is that their energy density and power output performance are lower than those of conventional lithium-ion batteries using a liquid electrolyte. To solve the above problems, in-depth research is being conducted on improving the electrodes of all-solid-state batteries.

[0006] Specifically, the anode for an all-solid-state battery is mainly formed of graphite. In this case, in order to ensure ionic conductivity, an excessive amount of a solid electrolyte having a large specific gravity is added together with the graphite, and thus the energy density per unit weight is very low compared to lithium-ion batteries. Moreover, when lithium metal is used as the anode, there are technical limitations in terms of price competitiveness and large-scale implementation.

[0007] In-depth research is currently being conducted on all-solid-state batteries with high energy density, and one of them is an anode-free all-solid-state battery. An anode-free all-solid-state battery is a battery in which lithium precipitates on the anode current collector instead of using an anode active material such as graphite or lithium metal.

[0008] However, conventional anode-free all-solid-state batteries have limitations in that the utilization rate of lithium is low because, for example, lithium grows unevenly in the form of dendrites or is isolated in the form of moss. Moreover, there is not enough space between the electrolyte layer and the anode current collector for lithium precipitation, and thus lithium precipitation is uneven, and there is also a problem that the dissociation reaction of lithium occurs unevenly due to the pressure exerted by the precipitated lithium varying with position. Summary of the Invention

[0009] In a preferred aspect, the present invention provides an anode-free all-solid-state battery capable of uniformly depositing lithium during charging.

[0010] As used herein, the term "anode-free all-solid-state battery" refers to an all-solid-state battery that lacks a counter electrode for the cathode, i.e., an anode, among compatible, parallel, and / or structurally similar external components. Instead, an anode-free all-solid-state battery may include functional components that similarly or equivalently serve as a conventional anode. In certain embodiments, an anode current collector layer may serve as a counter electrode for the cathode in an anode-free all-solid-state battery, excluding an anode layer (e.g., lacking an anode active material layer or a lithium layer) and forming a mismatched or asymmetric structure with the cathode.

[0011] The objectives of the present invention are not limited to the above objectives, and can be clearly understood through the following description, and can be achieved by the means described in the claims and their combinations.

[0012] In one aspect, the present invention provides an all-solid-state battery including an anode current collector layer, an electrolyte layer disposed on the anode current collector layer and including a solid electrolyte, and a composite cathode layer disposed on the electrolyte layer.

[0013] Specifically, the electrolyte layer may include: i) a plurality of recesses formed to be recessed from the surface of the electrolyte layer in contact with the anode current collector layer by a predetermined depth and width to serve as a space for storing lithium; ii) a first coating portion coated on the inner surface of each recess and including an oxide, and iii) a second coating portion coated on the first coating portion and including a conductive material.

[0014] The electrolyte layer may have a pattern in which the recesses are arranged regularly or irregularly.

[0015] The recesses may be formed to be recessed such that their walls are oriented at a right angle or a predetermined angle other than a right angle with respect to the surface of the electrolyte layer.

[0016] The ratio (W / H) of the width (W) to the depth (H) of the recesses may be from about 0.5 to 50.

[0017] The depth (H) of the recesses may suitably be about 30 μm to 200 μm.

[0018] The distance (L) between any one recess and another adjacent recess may suitably be about 5 μm to 50 μm.

[0019] The oxide compound may suitably include aluminum oxide (Al 2 O 3 ), zirconium oxide (ZrO 2 ) and combinations thereof.

[0020] The first coating portion may suitably have a thickness of about 0.1 nm to 1 μm.

[0021] The conductive material may suitably include one or more selected from the group consisting of carbon black, carbon nanotubes, graphite, gold, silver, copper, nickel, platinum, molybdenum, tungsten, and stainless steel.

[0022] The second coating portion may suitably have a thickness of about 0.1 nm to 10 μm.

[0023] During charging of the all-solid-state battery, lithium may precipitate on the second coating portion.

[0024] The electrolyte layer may further include a polymer material loaded into the space formed by the recesses.

[0025] The polymer material may include one or more selected from the group consisting of polyethylene oxide, polyacrylonitrile, polymethyl methacrylate, polyvinylidene fluoride, and polyethylene terephthalate.

[0026] During charging of the all-solid-state battery, lithium may precipitate between the second coating portion and the polymer material.

[0027] The present invention also provides a vehicle including the all-solid-state battery described herein.

[0028] According to various exemplary embodiments of the present invention, the all-solid-state battery does not include an anode active material layer, thus reducing the weight of the battery and greatly increasing its energy density per unit weight. Moreover, since lithium can be uniformly precipitated in the recesses of the electrolyte layer, the formation of dendritic lithium and dead lithium can be suppressed. In addition, since lithium can precipitate and grow in the recesses which are a kind of empty space, the pressure from lithium can be uniformly applied to the interface between the anode current collector layer and the electrolyte layer.

[0029] The effects of the present invention are not limited to those described above, and should be understood to include all effects that can be reasonably expected from the following description.

[0030] Other aspects of the present invention are disclosed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 An exemplary all-solid-state battery according to an exemplary embodiment of the present invention is shown;

[0032] Figure 2 An enlarged view of interface A between the anode current collector layer and the electrolyte layer according to an exemplary embodiment of the present invention is shown. Figure 1 of

[0033] Figure 3Shows a recess according to an exemplary embodiment of the present invention, the recess being formed to be recessed such that its walls are inclinedly oriented at a predetermined angle other than a right angle.

[0034] Figure 4 Shows a recess according to an exemplary embodiment of the present invention, the recess being formed to be recessed such that its walls are inclinedly oriented at a predetermined angle other than a right angle.

[0035] Figure 5 Shows the precipitation of lithium in the space formed by the recess during the charging process of an exemplary all - solid - state battery according to an exemplary embodiment of the present invention;

[0036] Figure 6 Shows an exemplary electrolyte layer according to an exemplary embodiment of the present invention;

[0037] Figure 7 Shows during the charging process of an all - solid - state battery, by Figure 6 the recess formed, the precipitation of lithium in the space;

[0038] Figure 8 Is the result of analyzing an all - solid - state battery of Example 1 according to an exemplary embodiment of the present invention using a scanning electron microscope.

[0039] Figure 9 Shows the measurement results of the capacities of the all - solid - state batteries of Example 1 and Example 2 according to an exemplary embodiment of the present invention; and

[0040] Figure 10 Shows the measurement results of the lifetimes of the exemplary all - solid - state batteries of Example 1 and a comparative example according to an exemplary embodiment of the present invention. Detailed Description

[0041] The above and other objects, features, and advantages of the present invention will be more clearly understood from the following preferred embodiments in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed herein and can be modified into different forms. These embodiments are provided to thoroughly explain the present invention and fully convey the spirit of the present invention to those skilled in the art.

[0042] In all the figures, the same reference numerals refer to the same or similar components. For the sake of clarity of the present invention, the dimensions of the structures are described as larger than their actual dimensions. It should be understood that although terms such as "first", "second", etc. may be used herein to describe various components, these components will not be limited by these terms. These terms are only used to distinguish one component from another. For example, without departing from the scope of the present invention, the "first" component discussed below may be referred to as the "second" component. Similarly, the "second" component may also be referred to as the "first" component. As used herein, the singular forms are also intended to include the plural forms unless the context clearly indicates otherwise.

[0043] It should also be understood that when used in this specification, the terms "comprises", "comprising", "has", etc. specify the presence of the stated features, integers, steps, operations, elements, components or combinations thereof. However, it does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components or combinations thereof. Moreover, it should be understood that when a component such as a layer, film, region or sheet is referred to as being "on" another component, it can be directly on the other component, or there may be intervening components between them. Similarly, when a component such as a layer, film, region or sheet is referred to as being "under" another component, it can be directly under the other component, or there may be intervening components between them.

[0044] Unless otherwise indicated, all numbers, values and / or representations of the amounts of components, reaction conditions, polymer compositions and mixtures used herein should be considered approximate values, including the various uncertainties inherent in the measurements made in obtaining these values, and should therefore be understood to be modified in all cases by the term "about".

[0045] Unless specifically stated or obvious from the context, as used herein, the term "about" should be understood to be within the normal tolerances in the art, for example within two standard deviations of the mean value. "About" can be understood to be within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05% or 0.01% of the stated value. Unless the context clearly indicates otherwise, all numerical values provided herein are modified by the term "about".

[0046] In addition, when a numerical range is disclosed in this specification, the range is continuous and includes all values from the minimum value of the range to its maximum value, unless otherwise specified. Moreover, when such a range pertains to integer values, all integers from the minimum value to the maximum value are included, unless otherwise indicated. For example, a range of "5 to 10" should be understood to include any sub-ranges, such as 6 to 10, 7 to 10, 6 to 9, 7 to 9, etc., as well as the individual values of 5, 6, 7, 8, 9, and 10. And it should also be understood to include any values between the valid integers within the range, such as 5.5, 6.5, 7.5, 5.5 to 8.5, 6.5 to 9, and so on. Additionally, for example, a range of "10% to 30%" will be understood to include sub-ranges such as 10% to 15%, 12% to 18%, 20% to 30%, etc., and all integer values including 10%, 11%, 12%, 13%, etc. (up to 30%), and it should also be understood to include any values between the valid integers within the range, such as 10.5%, 15.5%, 25.5%, and so on.

[0047] Figure 1 Shows an exemplary all-solid-state battery according to an exemplary embodiment of the present invention. The all-solid-state battery 1 includes an anode current collector layer 10, an electrolyte layer 20 disposed on the anode current collector layer 10, and a composite cathode layer 30 disposed on the electrolyte layer 20.

[0048] The anode current collector layer 10 may be formed in a plate-shaped or planar substrate.

[0049] The anode current collector layer 10 may be a metal thin film including a metal selected from the group consisting of copper (Cu), nickel (Ni), and combinations thereof. In particular, the anode current collector layer 10 may be a high-density metal thin film with a porosity of less than about 1%.

[0050] The thickness of the anode current collector layer 10 may be about 1 μm to 20 μm, particularly about 5 μm to 15 μm.

[0051] The electrolyte layer 20 may include a solid electrolyte having lithium ion conductivity.

[0052] The electrolyte layer 20 may include an oxide solid electrolyte or a sulfide solid electrolyte. A sulfide solid electrolyte with high lithium ion conductivity is preferably used. The sulfide solid electrolyte is not particularly limited and may include Li 2 S-P 2 S 5 、Li 2 S-P 2 S 5 -LiI、Li 2 S-P 2 S 5 -LiCl、Li2 S-P 2 S 5 -LiBr, Li 2 S-P 2 S 5 -Li 2 O, Li 2 S-P 2 S 5 -Li 2 O-LiI, Li 2 S-SiS 2 , Li 2 S-SiS 2 -LiI, Li 2 S-SiS 2 -LiBr, Li 2 S-SiS 2 -LiCl, Li 2 S-SiS 2 -B 2 S 3 -LiI, Li 2 S-SiS 2 -P 2 S 5 -LiI, Li 2 S-B 2 S 3 , Li 2 S-P 2 S 5 -Z m S n (where m and n are positive numbers, and Z is any one of Ge, Zn, and Ga), Li 2 S-GeS 2 , Li 2 S-SiS 2 -Li 3 PO 4 , Li 2 S-SiS 2 -Li x MO y (where x and y are positive numbers, and M is any one of P, Si, Ge, B, Al, Ga, and In), Li 10 GeP 2 S 12 etc.

[0053] The solid electrolyte layer may have a lithium ion conductivity of about 1×10 -4 S / cm or greater, and its particle size (D50) may be about 0.1 μm to 10 μm.

[0054] Figure 2 showsFigure 1 An enlarged view of the interface A between the anode current collector layer 10 and the electrolyte layer 20. The electrolyte layer 20 may include a plurality of recesses 21 formed to be recessed from one surface of the anode current collector layer 10 by a predetermined depth and width; a first coating portion 23 coated on the inner surface of each recess 21 and a second coating portion 25 coated on the first coating portion 23.

[0055] During the charging process of the all-solid-state battery 1, the recesses 21 may provide a space for the deposition and growth of lithium ions, which are generated from the composite cathode layer 30 and move through the electrolyte layer 20.

[0056] The electrolyte layer 20 may have a pattern in which the recesses 21 are arranged regularly or irregularly in the electrolyte layer. A "regular pattern" means that the recesses 21 are formed at constant intervals. The recesses 21 may have the same shape or different shapes. On the other hand, an "irregular pattern" means that the recesses 21 are formed unevenly rather than at constant intervals. For example, the recesses 21 may have the same shape or different shapes. According to various exemplary embodiments of the present invention, lithium may precipitate and grow in the recesses 21, thereby balancing the pressure applied to the interface between the electrolyte layer 20 and the anode current collector layer 10 due to lithium. For this purpose, it is desirable to form the recesses 21 in a regularly arranged pattern.

[0057] The recesses 21 may be formed to be recessed such that their walls are oriented at a right angle or a predetermined angle other than a right angle from one surface of the electrolyte layer 20. Figure 2 Shows a recess 21 formed to be recessed such that its wall is oriented at a right angle. Figure 3 and Figure 4 Shows a recess 21 formed to be recessed such that its wall is inclined and oriented at a predetermined angle other than a right angle.

[0058] In Figures 2 to 4 a part of the recesses 21 recessed from one surface of the electrolyte layer 20 are shown as straight lines for the convenience of a clearer understanding of the characteristics of the present invention, and the recesses 21 of the present invention should not be construed as being limited to Figures 2 - 4 the shape shown. When observed in cross-section, the recessed surface (hereinafter referred to as "side surface") of the recesses 21 may be straight and / or curved. When the side surface of the recesses 21 has a curved appearance, the recesses 21 are formed to be recessed at an angle defined by the tangent of the end of the curve and one surface of the electrolyte layer 20.

[0059] In addition, the three-dimensional shape of the recesses 21 is not particularly limited, and for example, it may be cylindrical, trumpet-shaped, or hemispherical.

[0060] The ratio (W / H) of the depth (H) to the width (W) of the recess 21 may be about 0.5 to 50, about 1 to 50, or about 1 to 25. Here, the depth (H) refers to the length by which the recess 21 is recessed from one surface of the electrolyte layer 20. Further, the width (W) refers to the longest distance between any two points where the side surface of the recess 21 contacts one surface of the electrolyte layer 20. When the ratio (W / H) is less than about 0.5, at the initial stage of charging, lithium will be concentratedly deposited on the protruding portions where lithium ion movement is likely to occur, so the recess 21 may collapse due to the force applied to the protruding portions. On the other hand, when the ratio is greater than about 50, the distance between the wall surface of the recess 21 where the precipitation and dissociation of lithium start and the center of the recess 21 may increase, and thus, irreversibly dissociated lithium may remain.

[0061] The depth (H) of the recess 21 may be about 30 μm to 200 μm. When the depth (H) is less than about 30 μm, there may not be enough space to accommodate the deposited lithium. On the other hand, when the depth is greater than about 200 μm, the movement of electrons from the anode current collector may be hindered.

[0062] The width (W) of the recess 21 may be about 25 μm to 2 mm. When the width (W) is less than about 25 μm, there may not be enough space to accommodate the deposited lithium. On the other hand, when the width is greater than about 2 mm, irreversibly dissociated lithium may remain at the center of the recess 21.

[0063] When the recesses 21 are formed in a pattern regularly arranged at constant intervals, the distance (L) between any one recess 21 and another adjacent recess 21' may be about 5 μm to 50 μm. The distance (L) refers to the shortest distance between any point where the side surface of any one recess 21 contacts one surface of the electrolyte layer 20 and another point where the side surface of the other recess 21' contacts one surface of the electrolyte layer 20.

[0064] The process of forming the recesses 21 is not particularly limited and may include, for example, forming a pattern by pressing a ceramic or metal substrate having an embossed or engraved pattern on one surface of the electrolyte layer 20, or forming a pattern by irradiating the electrolyte layer 20 with a laser or the like.

[0065] The first coating portion 23 is configured to deposit lithium uniformly in the recesses 21. Further, the first coating portion 23 can be used as a protective film that suppresses the reaction between the solid electrolyte of the electrolyte layer 20 and the deposited lithium.

[0066] The first coating portion 23 may include an oxide. For example, the first coating portion 23 may include a material selected from the group consisting of aluminum oxide (Al 2 O 3), zirconia (ZrO 2 ) and at least one of the group consisting of combinations thereof.

[0067] Since the first coating portion 23 has the property of forming a seed of lithium with a low contact angle, lithium can grow horizontally along the first coating portion 23. Therefore, lithium can be evenly deposited in the recess 21.

[0068] The thickness of the first coating portion 23 can be about 0.1 nm to 1 μm. When its thickness is less than about 0.1 nm, it may be difficult to obtain the desired effect. On the other hand, when its thickness is greater than about 1 μm, the movement of lithium ions may be hindered.

[0069] The process of forming the first coating portion 23 is not particularly limited, and examples thereof may include atomic layer deposition (ALD), physical vapor deposition (PVD), chemical vapor deposition (CVD), spraying, etc.

[0070] The second coating portion 25 is configured to move electrons. During the charging process of the all-solid-state battery 1, the lithium ions that have passed through the electrolyte layer 20 and the first coating portion 23 react with the electrons that have passed through the anode current collector layer 10 and the second coating portion 25, so that lithium can be deposited on the second coating portion 25.

[0071] The second coating portion 25 may include a conductive material. For example, the second coating portion 25 may include one or more selected from the group consisting of carbon black, carbon nanotubes, graphite, gold, silver, copper, nickel, platinum, molybdenum, tungsten, and stainless steel.

[0072] The thickness of the second coating portion 25 can be 0.1 nm to 10 μm. When its thickness is less than about 0.1 nm, the movement of electrons may be hindered. On the other hand, when its thickness is greater than about 10 μm, the coating processability may deteriorate, and the space amount in the recess 21 is limited, so its effect may be suppressed.

[0073] The process of forming the second coating portion 25 is not particularly limited, and examples thereof may include atomic layer deposition (ALD), physical vapor deposition (PVD), chemical vapor deposition (CVD), spraying, etc.

[0074] Figure 5 is a reference diagram showing the deposition of lithium (Li) in the space formed by the recess 21 during the charging process of the all-solid-state battery.

[0075] For example, lithium (Li) is uniformly deposited along the second coating portion 25, and the deposited lithium (Li) grows in a direction parallel to and intersecting the anode current collector layer 10. Since lithium nuclei with a low contact angle are formed by the first coating portion 23, lithium (Li) can mainly grow along the surface of the wall of the recess 21 toward the center of the recess 21. In short, lithium (Li) can grow in a direction parallel to the anode current collector layer 10. Therefore, according to various exemplary embodiments of the present invention, the growth rate of lithium dendrites can be reduced in the stacking direction of the electrolyte layer 20, the composite cathode layer 30, etc., and thus the short circuit of the all-solid-state battery can be suppressed.

[0076] Figure 6 Another illustration of the electrolyte layer 20 according to the present invention is shown. For example, the electrolyte layer 20 may include a polymer material 27 filled in the space formed by the recess 21.

[0077] Figure 7 is a reference diagram showing the deposition of lithium (Li) in the space formed by the Figure 6 recess 21 during the charging process of the all-solid-state battery.

[0078] During the charging process of the all-solid-state battery, lithium (Li) is deposited between the second coating portion 25 and the polymer material 27. Since the polymer material 27 is an elastic material, when lithium (Li) is deposited and dissociated, the structure of the recess 21, the bonding relationship between the electrolyte layer 20 and the anode current collector layer 10, etc. can be maintained.

[0079] The polymer material 27 may include one or more selected from the group consisting of polyethylene oxide, polyacrylonitrile, polymethyl methacrylate, polyvinylidene fluoride, and polyethylene terephthalate.

[0080] The composite cathode layer 30 may include a cathode active material layer 31 provided on the electrolyte layer 20 and a cathode current collector layer 33 provided on the cathode active material layer 31.

[0081] The cathode active material layer 31 may include a cathode active material, a solid electrolyte, a conductive material, an adhesive, etc.

[0082] The cathode active material may be an oxide active material or a sulfide active material.

[0083] The oxide active material may be a rock salt layer type active material, such as LiCoO 2 、LiMnO 2 、LiNiO 2 、LiVO 2 、Li 1+x Ni 1 / 3 Co 1 / 3 Mn 1 / 3O 2 etc.; spinel-type active materials such as LiMn 2 O 4 , Li(Ni 0.5 Mn 1.5 )O 4 etc.; inverse spinel-type active materials such as LiNiVO 4 , LiCoVO 4 etc.; olivine-type active materials such as LiFePO 4 , LiMnPO 4 , LiCoPO 4 , LiNiPO 4 etc.; silicon-containing active materials such as Li 2 FeSiO 4 , Li 2 MnSiO 4 etc.; rock-salt-layer-type active materials in which part of the transition metals are replaced by another metal, such as LiNi 0.8 Co (0.2-x) Al x O 2 (0 < x < 0.2); spinel-type active materials in which part of the transition metals are replaced by another metal, such as Li 1+x Mn 2-x-y M y O 4 (M is at least one of Al, Mg, Co, Fe, Ni, and Zn, 0 < x + y < 2); or lithium titanate, such as Li 4 Ti 5 O 12 etc.

[0084] The sulfide active material can be copper chevrel, iron sulfide, cobalt sulfide, nickel sulfide, etc.

[0085] The solid electrolyte can be an oxide solid electrolyte or a sulfide solid electrolyte. Herein, a sulfide solid electrolyte with high lithium ion conductivity is preferably used. The sulfide solid electrolyte is not particularly limited, but may include Li 2 S-P 2 S 5 ; Li 2 S-P 2 S 5 -LiI; Li 2 S-P 2 S 5 -LiCl; Li 2 S-P 2 S 5 -LiBr; Li 2 S-P2 S 5 -Li 2 O; Li 2 S-P 2 S 5 -Li 2 O-LiI; Li 2 S-SiS 2 ; Li 2 S-SiS 2 -LiI; Li 2 S-SiS 2 -LiBr; Li 2 S-SiS 2 -LiCl; Li 2 S-SiS 2 -B 2 S 3 -LiI; Li 2 S-SiS 2 -P 2 S 5 -LiI; Li 2 S-B 2 S 3 ; Li 2 S-P 2 S 5 -Z m S n (where m and n are positive numbers, and Z is any one of Ge; Zn; and Ga); Li 2 S-GeS 2 ; Li 2 S-SiS 2 -Li 3 PO 4 ; Li 2 S-SiS 2 -Li x MO y (where x and y are positive numbers, and M is any one of P; Si; Ge; B; Al; Ga; and In); Li 10 GeP 2 S 12 etc. The solid electrolyte may be the same as or different from the electrolyte included in the electrolyte layer 20.

[0086] The conductive material may suitably include carbon black, conductive graphite, ethylene black, graphene, etc.

[0087] The binder may suitably include BR (butadiene rubber), NBR (nitrile rubber), HNBR (hydrogenated nitrile rubber), VDF (vinylidene fluoride), PTFE (polytetrafluoroethylene), CMC (carboxymethyl cellulose), etc.

[0088] The cathode current collector layer 33 may suitably include aluminum foil or the like.

[0089] Examples

[0090] The present invention will be better understood from the following examples, which are merely illustrative of the present invention and do not limit the scope of the present invention.

[0091] Examples 1 and 2

[0092] A cathode paste is coated on the aluminum foil used as the cathode current collector layer to provide a cathode active material layer. NCM is used as the cathode active material, carbon black as the conductive material, an LPS-based solid electrolyte as the solid electrolyte, and butadiene rubber as the binder to prepare the cathode paste.

[0093] An electrolyte layer is formed by applying an LPS-based solid electrolyte on the composite cathode layer prepared as described above. A ceramic substrate having a cylindrical relief pattern is placed on the electrolyte layer and pressed, thereby forming a recess. In Example 1, the depth (H) of the recess is 70 μm and the width (W) is 150 μm. In Example 2, the depth (H) of the recess is 70 μm and the width (W) is 80 μm.

[0094] The ceramic substrate is removed, and alumina (Al 2 O 3 ) is applied to the inner surface of the recess by atomic layer deposition, thereby forming a first coating portion.

[0095] A second coating portion is formed by coating the first coating portion with sputtering gold (Au).

[0096] A nickel foam layer serving as the anode current collector layer is laminated on the electrolyte layer, thereby completing the all-solid-state battery.

[0097] Comparative example

[0098] An all-solid-state battery is manufactured in the same manner as in Examples 1 and 2, except that no recess is formed in the electrolyte layer.

[0099] Test Example 1 - Analysis using a scanning electron microscope (SEM)

[0100] The all-solid-state battery of Example 1 is observed using a scanning electron microscope. The results are shown in Figure 8 In. Figure 8 The observation results of the recess in the electrolyte layer and the lithium (bright) precipitated in the recess (dark) after charging the all-solid-state battery are shown.

[0101] Test Example 2 - Capacity analysis of all - solid - state battery

[0102] Measure the capacities of the all-solid-state batteries of Examples 1 and 2. The results are shown in Figure 9 , and the all-solid-state batteries of Examples 1 and 2 exhibited satisfactory capacities of 25 mAh or higher.

[0103] Test Example 3 - Life analysis of all - solid - state battery

[0104] Measure the lifetimes of the all-solid-state batteries of Example 1 and the comparative example. The results are shown in Figure 10 . The capacity of the all-solid-state battery of Example 1 remained unchanged even after 16 charge-discharge cycles. However, in the comparative example, the capacity decreased rapidly during charging / discharging.

[0105] As described above, the present invention has been described in detail in terms of test examples and examples. However, the scope of the present invention is not limited to the above test examples and examples, and various modified and improved modes of the present invention using the basic concepts of the present invention defined in the appended claims are also incorporated into the scope of the present invention.

Claims

1. A all-solid-state battery, comprising: an anode current collector layer; an electrolyte layer disposed on the anode current collector layer and comprising a solid electrolyte; and a composite cathode layer disposed on the electrolyte layer, wherein the electrolyte layer comprises i) a plurality of recesses formed to be recessed from the surface of the electrolyte layer in contact with the anode current collector layer by a predetermined depth and width so as to serve as a space for storing lithium; ii) a first coating portion coated on the surface of each recess and comprising an oxide-based compound; iii) a second coating portion coated on the first coating portion and comprising a conductive material.

2. The all-solid-state battery according to claim 1, wherein the electrolyte layer has a pattern in which the plurality of recesses are arranged regularly or irregularly.

3. The all-solid-state battery according to claim 1, wherein the recesses are formed to be recessed such that their walls are at a right angle or a predetermined angle other than a right angle to the surface of the electrolyte layer.

4. The all-solid-state battery according to claim 1, wherein the ratio (W / H) of the width (W) to the depth (H) of the recesses is from 0.5 to 50.

5. The all-solid-state battery according to claim 1, wherein the depth (H) of the recesses is from 30 μm to 200 μm.

6. The all-solid-state battery according to claim 1, wherein the distance (L) between any one recess and another adjacent recess is from 5 μm to 50 μm.

7. The all-solid-state battery according to claim 1, wherein the oxide compound includes aluminum oxide (Al 2 O 3 ), zirconium oxide (ZrO 2 ), or a combination thereof.

8. The all-solid-state battery according to claim 1, wherein the thickness of the first coating portion is from 0.1 nm to 1 μm.

9. The all-solid-state battery according to claim 1, wherein the conductive material comprises one or more selected from the group consisting of carbon black, carbon nanotubes, graphite, gold, silver, copper, nickel, platinum, molybdenum, tungsten, and stainless steel.

10. The all-solid-state battery according to claim 1, wherein the thickness of the second coating portion is from 0.1 nm to 10 μm.

11. The all-solid-state battery according to claim 1, wherein during the charging process of the all-solid-state battery, lithium is deposited on the second coating portion.

12. The all-solid-state battery according to claim 1, wherein the electrolyte layer further comprises a polymer material filled in the space formed by the recesses.

13. The all-solid-state battery according to claim 12, wherein the polymer material comprises one selected from the group consisting of polyethylene oxide, polyacrylonitrile, polymethyl methacrylate, polyvinylidene fluoride, and polyethylene terephthalate.

14. The all-solid-state battery according to claim 12, wherein during the charging process of the all-solid-state battery, lithium is deposited between the second coating portion and the polymer material.

15. A vehicle comprising the all-solid-state battery according to claim 1.

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