All-solid-state rechargeable battery and manufacturing method thereof

Abstract

Provided are: an all-solid-state rechargeable battery comprising a positive electrode, a negative electrode, and a solid electrolyte layer disposed between the positive electrode and the negative electrode and including an inorganic solid electrolyte, wherein the negative electrode includes a patterned negative electrode current collector and a negative electrode coating layer disposed on the patterned negative electrode current collector and including a lithium-philic metal, a carbon material, or a combination thereof; and a manufacturing method thereof.

Description

All-solid-state secondary battery and method for manufacturing the same

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

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

[0003] Because lithium secondary batteries on the market use electrolytes containing flammable organic solvents, there is a safety issue that the batteries may explode or catch fire in the event of a collision or penetration.

[0004] Accordingly, all-solid-state secondary batteries, which utilize solid electrolytes instead of liquid electrolytes, are being proposed. All-solid-state secondary batteries are composed entirely of solid materials, offering safety advantages such as no risk of electrolyte leakage or explosion, and the ease of manufacturing thin batteries. Furthermore, a reduced anode thickness allows for improved high-speed charge / discharge performance, enabling high-voltage operation and high-energy density.

[0005] One embodiment is to provide an all-solid-state secondary battery and a method for manufacturing the same, which can improve lifespan and stability by resolving morphological instability and suppressing the formation of lithium dendrites.

[0006] One embodiment provides an all-solid-state secondary battery comprising: a positive electrode; a negative electrode; and a solid electrolyte layer positioned between the positive electrode and the negative electrode and including an inorganic solid electrolyte; wherein the negative electrode comprises a patterned negative electrode current collector; and a negative electrode coating layer positioned on the patterned negative electrode current collector and including a lithium-philic metal, a carbon material, or a combination thereof.

[0007] Another embodiment provides a method for manufacturing an all-solid-state secondary battery, comprising: preparing a laminate comprising a positive electrode; a negative electrode; and a solid electrolyte layer positioned between the positive electrode and the negative electrode and including an inorganic solid electrolyte; applying pressure to the laminate to adjust alignment of the laminate; wherein the negative electrode comprises a patterned negative electrode current collector; and a negative electrode coating layer positioned on the patterned negative electrode current collector and including a lithium-philic metal, a carbon material, or a combination thereof.

[0008] According to one embodiment, an all-solid-state secondary battery and a method for manufacturing the same can be provided that can resolve morphological instability and improve lifespan and stability by suppressing the formation of lithium dendrites.

[0009] Figures 1 to 3 are cross-sectional views schematically showing an all-solid-state secondary battery according to one embodiment.

[0010] Figure 4 is a schematic cross-sectional view showing an enlarged portion of a pressurized laminate according to one embodiment.

[0011] Figure 5 is a schematic cross-sectional view showing an enlarged portion of an all-solid-state secondary battery according to one embodiment.

[0012] Figure 6 is a plan view schematically showing a lattice structure on a plane of a patterned negative electrode collector according to one embodiment.

[0013] Figure 7 shows the pressure gradient results in the solid electrolyte layer measured while changing the pressure during pressurization to 5 MPa, 10 MPa, 20 MPa, and 30 MPa for the laminate manufactured in Example 1 to evaluate the influence of the shape of the patterned negative current collector on the pressure gradient in the solid electrolyte layer for an all-solid-state secondary battery.

[0014] Figure 8 shows the pressure gradient results in the solid electrolyte layer measured while changing the pressure during pressurization to 5 MPa, 10 MPa, 20 MPa, and 30 MPa for the laminate manufactured in Comparative Example 1 to evaluate the influence of the shape of the patterned negative current collector on the pressure gradient in the solid electrolyte layer for an all-solid-state secondary battery.

[0015] FIG. 9 is a schematic diagram of the growth process of electrodeposited lithium (or lithium-containing layer) when the pressure during pressurization of the laminate is too low during the manufacturing process of an all-solid-state secondary battery according to one embodiment.

[0016] Figure 10 is a schematic diagram of the growth process of electrodeposited lithium (or lithium-containing layer) when the pressure during pressurization of the laminate is within an appropriate pressure range during the manufacturing process of an all-solid-state secondary battery according to one embodiment.

[0017] Figure 11 shows the flux results of ion current and a photograph taken by SEM of the interface between the patterned negative electrode collector and the solid electrolyte layer to confirm the form of the electrodeposited lithium (or lithium-containing layer) for the all-solid-state secondary battery manufactured in Example 1.

[0018] Figure 12 shows the flux results of ion current and a photograph taken by SEM of the interface between the patterned negative electrode collector and the solid electrolyte layer to confirm the form of the electrodeposited lithium (or lithium-containing layer) for the all-solid-state secondary battery manufactured in Example 2.

[0019] Figure 13 shows the flux results of ion current and a photograph taken by SEM of the interface between the patterned negative electrode collector and the solid electrolyte layer to confirm the form of the electrodeposited lithium (or lithium-containing layer) for the all-solid-state secondary battery manufactured in Example 3.

[0020] Figure 14 shows the flux results of ion current and a photograph taken by SEM of the interface between the patterned negative electrode collector and the solid electrolyte layer to confirm the form of the electrodeposited lithium (or lithium-containing layer) for the all-solid-state secondary battery manufactured in Example 4.

[0021] Figure 15 shows the flux results of ion current and a photograph taken by SEM of the interface between the patterned negative electrode collector and the solid electrolyte layer to confirm the form of the electrodeposited lithium (or lithium-containing layer) for the all-solid-state secondary battery manufactured in Reference Example 1.

[0022] Figure 16 shows the flux results of ion current and a photograph taken by SEM of the interface between the patterned negative electrode collector and the solid electrolyte layer to confirm the form of the electrodeposited lithium (or lithium-containing layer) for the all-solid-state secondary battery manufactured in Reference Example 2.

[0023] Figure 17 shows the flux results of ion current and a photograph taken by SEM of the interface between the patterned negative electrode collector and the solid electrolyte layer to confirm the form of the electrodeposited lithium (or lithium-containing layer) for the all-solid-state secondary battery manufactured in Reference Example 3.

[0024] Figure 18 shows the flux results of ion current and a photograph taken by SEM of the interface between the patterned negative electrode collector and the solid electrolyte layer to confirm the form of the electrodeposited lithium (or lithium-containing layer) for the all-solid-state secondary battery manufactured in Reference Example 4.

[0025] Figure 19 shows the flux results of ion current and a photograph taken by SEM of the interface between the patterned negative electrode collector and the solid electrolyte layer to confirm the form of the electrodeposited lithium (or lithium-containing layer) for the all-solid-state secondary battery manufactured in Reference Example 5.

[0026] Figure 20 is a reference index of the current density evaluated in Figures 11 to 19.

[0027] Figure 21 shows the evaluation results of voltage changes according to capacity during operation for all-solid-state secondary batteries manufactured in Example 1, Reference Examples 1 and 2, and Comparative Example 1.

[0028] Figure 22 shows the evaluation results of voltage changes according to capacity during operation for all-solid-state secondary batteries manufactured in Example 3, Reference Examples 4 and 5, and Comparative Example 2.

[0029] Figures 23 and 24 show photographs taken using an SEM of the interface on the solid electrolyte layer side, with the patterned negative electrode collector and the solid electrolyte layer separated, in which lithium was deposited on the patterned negative electrode collector by driving the all-solid-state secondary battery manufactured in Example 2.

[0030] Figure 25 shows a photograph taken using BSE of the interface on the solid electrolyte layer side, with the patterned negative electrode collector and the solid electrolyte layer separated, in which lithium was deposited on the patterned negative electrode collector by driving the all-solid-state secondary battery manufactured in Example 2.

[0031] Figure 26 shows the results of measuring voltage changes according to the number of cycles for all-solid-state secondary batteries manufactured in Example 3 and Comparative Example 3.

[0032] Figure 27 is the result of voltage change according to capacity in the first cycle in Figure 26.

[0033] Figure 28 is the result of voltage change according to capacity in the 7th cycle in Figure 26.

[0034] Figure 29 is the result of the removal capacity according to the number of cycles in Figure 26.

[0035] Hereinafter, embodiments of the present invention will be described in detail. However, these are presented as examples and are not intended to limit the present invention. The present invention is defined solely by the scope of the claims set forth below.

[0036] Unless otherwise specified herein, when a part such as a layer, film, region, plate, etc. is said to be “on” another part, this includes not only cases where it is “directly on” the other part, but also cases where there is another part in between.

[0037] Unless otherwise specified herein, the singular may also include the plural. Furthermore, unless otherwise specified, "A or B" may mean "including A, including B, or including A and B."

[0038] As used herein, “combination thereof” may mean mixtures, laminates, composites, copolymers, alloys, blends, and reaction products of the components.

[0039] Unless otherwise defined in this specification, the particle size may be the average particle size. In addition, the particle size may be the average particle size (D), which means the diameter of particles with a cumulative volume of 50% by volume in the particle size distribution. 50 ) means the average particle diameter (D 50 ) can be measured by methods widely known to those skilled in the art, for example, by measuring with a particle size analyzer, or by measuring with a transmission electron microscope photograph or a scanning electron microscope photograph. Alternatively, a measuring device using dynamic light-scattering is used for measurement, and the number of particles is counted for each particle size range by performing data analysis, and then the average particle diameter (D) is calculated from this. 50) value can be obtained. Or, it can be measured using the laser diffraction method. When measuring by the laser diffraction method, more specifically, after the particles to be measured are dispersed in a dispersion medium, they are introduced into a commercially available laser diffraction particle size measuring device (e.g., Microtrac MT 3000) and irradiated with ultrasonic waves of about 28 kHz at an output of 60 W, and then the average particle diameter (D) based on 50% of the particle size distribution in the measuring device is measured. 50 ) can be produced.

[0040] It should be understood that the terms "include," "comprising," or "having" herein are intended to specify the presence of a feature, number, step, component, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, components, or combinations thereof.

[0041] Also, here, “layer” includes not only the shape formed on the entire surface when observed in a plan view, but also the shape formed on a portion of the surface.

[0042] “Metal” is interpreted as a concept that includes common metals, transition metals, and metalloids (semi-metals).

[0043] “Thickness” may be measured, for example, from photographs taken with an optical microscope, such as a scanning electron microscope.

[0044] All-solid-state secondary battery

[0045] One embodiment provides an all-solid-state secondary battery comprising: a positive electrode; a negative electrode; and a solid electrolyte layer positioned between the positive electrode and the negative electrode and including an inorganic solid electrolyte; wherein the negative electrode comprises a patterned negative electrode current collector; and a negative electrode coating layer positioned on the patterned negative electrode current collector and including a lithium-philic metal, a carbon material, or a combination thereof.

[0046] All-solid-state secondary batteries are considered a groundbreaking solution that can overcome the limitations of conventional liquid electrolyte-based lithium secondary batteries. In particular, solid electrolytes are considered a next-generation electrolyte that can ensure the safety of lithium-ion batteries due to their high thermal stability and non-flammability. Among various types of solid electrolytes, interest in inorganic solid electrolytes, such as sulfide-based solid electrolytes, is growing, as their ionic conductivity is comparable to or superior to that of liquid electrolytes.

[0047] However, to realize a usable all-solid-state secondary battery, two critical issues must be addressed: interfacial instability and morphological instability. Interfacial instability arises from poor interfacial contact between the solid electrolyte and the solid electrode, which can lead to high interfacial resistance. Morphological instability arises from the growth of lithium dendrites that penetrate the solid electrolyte and the non-uniformly formed electrodeposited lithium at the interface, which can lead to short circuits or thermal runaway of the battery. This instability becomes more pronounced at high operating current densities and is a major factor hindering the practical application of all-solid-state secondary batteries. To address these issues, various methods have been applied, such as inserting artificial interfacial layers composed of carbon allotropes, alloys, or ceramics into the interface.

[0048] That is, the challenge of morphological instability is clear. It occurs as deposited lithium diffuses along grain boundaries in inorganic solid electrolytes, which can lead to short circuits. This diffusion can also lead to electrolyte cracking, further exacerbating the instability. Previous studies have shown that even small amounts of deposited lithium can induce electrolyte cracking within ceramic electrolytes. Morphological instability can be even more severe in lithium-free cell configurations, and deposited lithium on the current collector can cause serious damage to the electrolyte.

[0049] Accordingly, in one embodiment, an all-solid-state secondary battery capable of resolving morphological instability by combining suitable three-dimensional structures and materials is proposed.

[0050] An all-solid-state secondary battery according to one embodiment includes: a positive electrode; a negative electrode; and a solid electrolyte layer positioned between the positive electrode and the negative electrode and including an inorganic solid electrolyte.

[0051] In an all-solid-state secondary battery according to one embodiment, the negative electrode includes a patterned negative electrode collector. FIG. 5 is a schematic cross-sectional view schematically illustrating a portion of an all-solid-state secondary battery according to one embodiment. For example, the patterned negative electrode collector (41) may include a base portion (10); a protrusion portion (11) protruding from the base portion; and a groove portion (12) set between adjacent protrusions. Traditionally, a flat and smooth electrode structure was formed, and it was preferred to apply external pressure to such an electrode structure. In addition, even if the negative electrode is structurally patterned, although a technology for patterning the negative electrode active material layer or the interface layer was previously applied, the negative electrode active material layer or the interface layer did not have sufficient mechanical properties, so there were problems such as being easily broken or cracked when applying pressure or during use. Contrary to this conventional perception, in one embodiment, a rough structure is introduced to a patterned negative electrode collector (41) in the interface region between the negative electrode (400) and the solid electrolyte layer (300). The protrusions (11), which are contact regions, and the grooves (12), which are non-contact regions, of the patterned negative electrode collector (41) can also create corresponding regions at the interface with the solid electrolyte layer (300), thereby forming a pressure gradient between the contact region and the non-contact region in the interface region between the solid electrolyte layer and the negative electrode, thereby resolving morphological instability.

[0052] For example, a lithium-containing layer (or, electrodeposited lithium) positioned within the groove (12) may be further included, for example, the lithium-containing layer may include electrodeposited lithium, and the lithium-containing layer may include lithium metal or a lithium alloy. At this time, the lithium-containing layer may be formed by the operation of the battery or by the charging of the battery. In the past, it was recognized that a uniform pressure distribution is necessary to reduce morphological instability, and thus, studies have been conducted to form a uniform pressure distribution at the interface of the negative electrode. However, in one embodiment, unlike the existing concept, a patterned negative electrode collector is used in an all-solid-state secondary battery, and by applying external pressure to the laminate during the manufacturing process, an uneven pressure distribution can be induced at the interface of the solid electrolyte and the negative electrode, thereby suppressing the growth of lithium dendrites. When applying external pressure to the laminate using such a patterned negative electrode collector, lithium ions (Li) are formed by the external pressure. + ) flux can be induced into the groove portion (12) of the patterned negative electrode collector, which is the void region of the interface, and as a result, a lithium-containing layer including electrodeposited lithium can be preferentially formed within the groove portion (12). This induction of the morphology of electrodeposited lithium (or lithium-containing layer including electrodeposited lithium) according to the non-uniform pressure distribution can provide a new perspective on the interface design of an all-solid-state secondary battery, thereby improving the lifespan and stability of the battery.

[0053] For example, when the lithium-containing layer (or, electrodeposited lithium) located within the home portion (12) includes a lithium alloy, the lithium alloy may be, for example, a Li-Al alloy, a Li-Sn alloy, a Li-In alloy, a Li-Ag alloy, a Li-Au alloy, a Li-Zn alloy, a Li-Ge alloy, or a Li-Si alloy. When this is satisfied, the role of a lithium storage can be sufficiently performed, and performance degradation due to an increase in battery volume can be prevented.

[0054] For example, the thickness of the lithium-containing layer (or, electrodeposited lithium) located within the groove (12) may be 1 µm to 500 µm, 1 µm to 200 µm, 1 µm to 100 µm, 1 µm to 80 µm, or 5 µm to 80 µm. Within the above range, the lithium storage layer can sufficiently perform its role and prevent performance degradation due to an increase in battery volume.

[0055] A lattice structure for a plane of a patterned negative electrode collector according to an embodiment is illustrated in FIG. 6. For example, as illustrated in FIG. 6, the grooves (12) and the protrusions (11) of the patterned negative electrode collector (41) may form a lattice structure with respect to the plane of the base (10), and as illustrated in FIG. 6, the shapes of the grooves (12) and the protrusions (11) may be square with respect to the cross-section of the patterned negative electrode collector (41), for example, may be a regular square shape. As described above, by using a patterned negative electrode collector in which the cross-sections of the grooves (12) and the protrusions (11) are square, a pressure gradient is formed between the contact area and the non-contact area, so that when an external pressure (or, lamination pressure) is applied to the laminate, a relatively uniform interfacial contact can be ensured, and also, the pressure gradient occurring in the interfacial area can cause lithium ions (Li + ) can be guided to the groove (12), which is the empty space side of the patterned negative electrode collector, so that the electrodeposited lithium (or lithium-containing layer) can be concentrated within the groove (12).

[0056] For example, the depth (H) of the groove (12) may be 2 µm to 60 µm, 3 µm to 55 µm, 5 µm to 50 µm, or 10 µm to 30 µm. In this range, it may be advantageous to preferentially form a lithium-containing layer including electrodeposited lithium within the groove by using a patterned negative electrode collector, and to secure the effect of suppressing the occurrence of lithium dendrites.

[0057] For example, the width (W) of the groove (12) may be 5 µm to 70 µm, 8 µm to 65 µm, 30 µm to 60 µm, or 40 µm to 50 µm. In this range, it may be advantageous to preferentially form a lithium-containing layer including electrodeposited lithium within the groove by using a patterned negative electrode collector, and to secure the effect of suppressing the occurrence of lithium dendrites.

[0058] For example, the width (L) of the protrusion (11) may be 1 µm to 50 µm, 8 µm to 45 µm, 10 µm to 40 µm, or 20 µm to 30 µm. In this range, it is possible to sufficiently secure conductivity according to the movement of lithium ions without hindering the effect of suppressing the generation of lithium dendrites by using a patterned negative electrode collector.

[0059] For example, the thickness of the negative electrode current collector may be 5 μm to 200 μm, 8 μm to 150 μm, 10 μm to 100 μm, or 30 μm to 80 μm. Within this range, the mechanical strength of the negative electrode can be sufficiently secured, while effectively suppressing the formation of lithium dendrites resulting from the use of the patterned negative electrode current collector.

[0060] The ratio of the depth of the groove to the total thickness of the negative electrode current collector may be 10% to 90%, 20% to 80%, or 30% to 60%. In this range, it may be advantageous to secure the effect of preferentially forming a lithium-containing layer including electrodeposited lithium within the groove by using a patterned negative electrode current collector and suppressing the occurrence of lithium dendrites.

[0061] For example, the negative electrode current collector may include copper foil, nickel foil, lithium foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, or a combination thereof. A representative example of the negative electrode current collector may be nickel foil. When copper foil is used as the negative electrode current collector, cracks may occur in the solid electrolyte as the electrodeposited lithium is formed. To prevent this, in one embodiment, nickel foil may be used as the negative electrode current collector as described above.

[0062] In one embodiment, a lithium metal layer formed by charging may be further included between the negative electrode current collector and the negative electrode coating layer, and the lithium metal layer may include lithium metal or a lithium alloy. For example, the all-solid-state secondary battery according to one embodiment may include a precipitation-type negative electrode as the negative electrode, and in addition to the lithium-containing layer positioned within the groove, may further include a lithium metal layer. In this case, the following description may be equally applied to the precipitation-type negative electrode or the lithium metal layer.

[0063] Meanwhile, the following description can be equally applied to the aforementioned positive electrode, negative electrode, solid electrolyte layer, and inorganic solid electrolyte.

[0064] Method for manufacturing an all-solid-state secondary battery

[0065] One embodiment provides a method for manufacturing an all-solid-state secondary battery, comprising: preparing a laminate comprising a positive electrode; a negative electrode; and a solid electrolyte layer positioned between the positive electrode and the negative electrode and including an inorganic solid electrolyte; and applying pressure to the laminate, wherein the negative electrode comprises a patterned negative electrode current collector; and a negative electrode coating layer positioned on the patterned negative electrode current collector and including a lithium-philic metal, a carbon material, or a combination thereof.

[0066] The above description relates to a method for manufacturing an all-solid-state secondary battery, which is an example of an embodiment. Below, descriptions overlapping with the above descriptions are omitted, and a process for manufacturing an all-solid-state secondary battery, which is an example of an embodiment, is described in detail.

[0067] First, a laminate is prepared, including an anode; a cathode; and a solid electrolyte layer positioned between the anode and the cathode and including an inorganic solid electrolyte. Conventional methods in the art can be used without limitation for the formation of each layer.

[0068] For example, the positive electrode, negative electrode, and solid electrolyte layer can be formed by applying a slurry for forming each layer, and then drying or drying and rolling. For example, the solid electrolyte layer can be formed by applying a slurry for forming a solid electrolyte layer to pelletize the slurry, and then rolling the applied slurry for forming a solid electrolyte layer at a high pressure of 300 MPa to 600 MPa to pelletize the slurry.

[0069] Next, the laminate can be pressurized. Through the pressurization, the alignment of the laminate can be adjusted, and for example, the pressurization can be performed by uniaxial pressurization. Through the pressurization process, the direction and position of formation of electrodeposited lithium (or a lithium-containing layer including electrodeposited lithium) formed on the patterned negative electrode collector during operation or charging of the battery can be controlled. In addition, through the pressurization process, not only can the interfacial contact between each layer in the final solid-state secondary battery be improved, but also the material transfer between each layer can be controlled by mechanical energy rather than electrical energy.

[0070] An enlarged cross-sectional view schematically showing a portion of a pressurized laminate according to an embodiment is shown in FIG. 4, and an enlarged cross-sectional view schematically showing a portion of a pressurized laminate (or, an all-solid-state secondary battery) according to an embodiment is shown in FIG. 5. As shown in FIG. 4, before pressing the laminate, a groove (12) may be formed throughout the entire thickness direction of the cross-section of the negative electrode current collector (401), and thus, the laminate may be formed in a form that is perforated by the groove (12). However, as shown in FIG. 5, after pressing the laminate, the groove (12) located on the side that contacts the pressing device may be pressed by the uniaxial pressing, thereby forming the base (10).

[0071] For example, the pressure during the pressurization may be 5 MPa to 50 MPa, 10 MPa to 50 MPa, 15 MPa to 45 MPa, or 20 MPa to 40 MPa. Fig. 9 is a schematic diagram showing a growth process of electrodeposited lithium (or lithium-containing layer) when the pressure during pressurization of the laminate is too low during the manufacturing process of an all-solid-state secondary battery according to one embodiment. In addition, Fig. 10 is a schematic diagram showing a growth process of electrodeposited lithium (or lithium-containing layer) when the pressure during pressurization of the laminate is within an appropriate pressure range during the manufacturing process of an all-solid-state secondary battery according to one embodiment. Referring to Fig. 9, if the pressure during pressurization of the laminate is too low or if the laminate is not pressurized, lithium deposition (20) may be formed mainly on the protrusions (11) of the patterned negative electrode current collector (41), which may cause the growth of lithium dendrites (30) that penetrate the solid electrolyte and head toward the opposite electrode, potentially causing an internal short circuit. On the other hand, referring to Fig. 10, if the pressure during pressurization of the laminate is within the appropriate pressure range, Li +The flux of the electrodeposited lithium (20) is guided toward the groove (12) of the patterned negative electrode collector (41), and the nucleus growth of the electrodeposited lithium (20) begins to occur at the edge of the groove (12), and thereafter, the growth of the electrodeposited lithium (20) progresses into the interior of the groove (12). Therefore, at an appropriate pressure satisfying the above range, the electrodeposited lithium (or the lithium-containing layer including the electrodeposited lithium) (20) can be induced to be formed intensively only within the groove (12) of the patterned negative electrode collector (41), thereby effectively suppressing the occurrence of lithium dendrites and preventing an internal short circuit from occurring.

[0072] According to one implementation example, lithium ion (Li + ) Based on the current and the form of electrodeposited lithium (or lithium-containing layer), Li + There may be an appropriate pressure that can induce the flux toward the groove (12) of the patterned negative electrode collector (41). When the stack is not pressurized (i.e., when the pressure during the pressurization is 0 MPa), electrodeposited lithium (20) can be formed on the protrusion (11) regardless of the operating temperature and operating current density described later, which can be evidenced by the ionic current appearing locally on the protrusion (11). However, when the pressure during the pressurization applied to the stack increases, the effect of the ionic current induced by the pressure gradient becomes more pronounced, and a distortion phenomenon of the ionic current may occur in the interface region. When the pressurization is performed, the direction of the ionic current deviates significantly at high pressure, and when the stack pressure is higher than a certain pressure, the current may flow in the opposite direction near the protrusion (11) and flow toward the groove (12). This is because the contribution of the ionic current is greatly increased by the pressure gradient, and this phenomenon can induce the electrodeposited lithium to be formed preferentially on the groove (12) side rather than on the protrusion (11) side.

[0073] For example, the working current density is 0.05 mA / cm 21.5 mA / cm 2 , 0.1 mA / cm 2 1.0 mA / cm 2 , 0.1 mA / cm 2 0.8 mA / cm 2 , or 0.1 mA / cm 2 0.5 mA / cm 2 It can be adjusted within the range. The operating current density is one of the important variables that control the morphology of electrodeposited lithium in an all-solid-state secondary battery, and depending on the change in the operating current density, the performance, stability, and morphological instability of the battery can be controlled, and the optimized operating current density can play a key role in ensuring the long-term reliability of the electrode and the battery. Therefore, by setting the operating current density within an appropriate range, the electrodeposited lithium (or lithium-containing layer) can be stably formed within the grooves of the patterned negative electrode collector, thereby improving the lifespan and stability of the battery. Therefore, when the operating current density satisfies the above range, the electrodeposited lithium (or lithium-containing layer) can be formed intensively within the grooves of the patterned negative electrode collector, and the occurrence of internal short circuits due to the occurrence of lithium dendrites can be effectively prevented. Within the above range, the lower the operating current density, the better the effect of suppressing the growth of lithium dendrites by forming an uneven pressure distribution at the interface between the solid electrolyte and the negative electrode by applying a specific external pressure to the laminate, and the higher the operating current density, the less the effect of applying a specific external pressure to the laminate, and the greater the possibility that electrodeposited lithium will not be uniformly formed inside the groove.

[0074] For example, the operating temperature can be controlled in the range of 20°C to 170°C, 25°C to 160°C, 30°C to 150°C, 45°C to 150°C, or 45°C to 100°C. The operating temperature is also one of the factors that significantly affects the morphology of the electrodeposited lithium. As the operating temperature increases, the mobility of lithium ions increases, which improves lithium ion conduction in the electrolyte and makes ion flow easier. Therefore, within the above range, the higher the operating temperature, the stronger the Li + When flux is generated, lithium (or a lithium-containing layer) can be effectively formed into the grooves of a patterned negative electrode collector when compared under the same operating current density conditions, thereby preventing the formation of lithium dendrites, thereby reducing the risk of internal short circuits and improving the stability of the battery. In addition, the higher the operating temperature, the more the effect of applying a specific external pressure to the laminate can be strengthened, and the morphological characteristics of the lithium (or a lithium-containing layer) positioned into the grooves of the patterned negative electrode collector can be more distinct.

[0075] For example, the method for manufacturing the above-described all-solid-state secondary battery may satisfy at least one of the following conditions 1 and 2. When this is satisfied, it is possible to effectively control the formation of electrodeposited lithium (or lithium-containing layer) concentrated within the groove portion of the patterned negative electrode current collector.

[0076] Condition 1: The pressure during the pressurization is 10 MPa to 50 MPa.

[0077] Condition 2: The pressure during pressurization is 5 MPa or more and less than 10 MPa, the operating temperature is 45 ℃ to 100 ℃, and the operating current density is 0.1 mA / cm 2 0.8 mA / cm 2 It is

[0078] In a method for manufacturing an all-solid-state secondary battery, the negative electrode may include a patterned negative electrode current collector; and an negative electrode coating layer positioned on the patterned negative electrode current collector and including a lithium-philic metal, a carbon material, or a combination thereof. In this case, the above-described description may be equally applied to the negative electrode, and therefore a detailed description thereof is omitted herein.

[0079] FIG. 1 is a cross-sectional view of an all-solid-state secondary battery according to an embodiment. Referring to FIG. 1, the all-solid-state secondary battery (100) may have a structure in which an electrode assembly in which a negative electrode (400) including a negative electrode current collector (401) and a negative electrode active material layer (403); a solid electrolyte layer (300); and a positive electrode (200) including a positive electrode active material layer (203) and a positive electrode current collector (201) are laminated is housed in a battery case. The all-solid-state secondary battery (100) may further include an elastic sheet (500) on the outer side of at least one of the positive electrode (200) and the negative electrode (400). In FIG. 1, one unit cell including a negative electrode (400), a solid electrolyte layer (300), and a positive electrode (200) is illustrated. However, as illustrated in FIG. 3, two unit cells may be stacked to manufacture an all-solid-state secondary battery, or two or more unit cells may be stacked, for example, 2 to 100, 3 to 50, 4 to 20, etc., to manufacture an all-solid-state secondary battery. In addition, the unit cell may include one or more negative electrodes, and similarly, one or more solid electrolyte layers, and one or more positive electrodes. For example, the unit cell may be a monocell having a positive electrode / solid electrolyte layer / negative electrode structure, or a bicell having a negative electrode / solid electrolyte layer / positive electrode / solid electrolyte layer / negative electrode structure. Here, the negative electrode current collector (401) may be a patterned negative electrode current collector (41), and the above-described description may be equally applied to this.

[0080] anode

[0081] In one embodiment, the device may include a positive electrode current collector and a positive electrode active material layer formed on the positive electrode current collector. The positive electrode active material layer may include a positive electrode active material, may further include a solid electrolyte, and may further include a binder and a conductive material.

[0082] positive electrode active material

[0083] The above positive electrode active material can be applied without limitation as long as it is generally used in all-solid-state secondary batteries. For example, the positive electrode active material may use a compound capable of reversible intercalation and deintercalation of lithium, may include a lithium transition metal composite oxide, and may include a compound represented by any one of the following chemical formulas. Li a A 1-b X b O 2-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Mn 2-b X b O 4-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Ni 1-b-c Co b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni 1-b-c Mn b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni b Co c L 1 d G e O2(0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0≤e≤0.1); Li a NiG bO2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a CoG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-b G b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn2G b O4(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-g G g PO4(0.90≤a≤1.8, 0≤g≤0.5); Li (3-f) Fe2(PO4)3(0≤f≤2); Li a FePO4(0.90≤a≤1.8).

[0084] The positive electrode active material may include, for example, lithium cobalt oxide (LCO), lithium nickel oxide (LNO), lithium nickel cobalt oxide (NC), lithium nickel cobalt aluminum oxide (NCA), lithium nickel cobalt manganese oxide (NCM), lithium nickel manganese oxide (NM), lithium manganese oxide (LMO), lithium iron phosphate oxide (LFP), or a combination thereof.

[0085] The positive electrode active material may include, for example, a lithium nickel-based oxide represented by the following chemical formula 1A, a lithium cobalt-based oxide represented by the following chemical formula 2A, a lithium iron phosphate-based compound represented by the following chemical formula 3A, a cobalt-free lithium nickel-manganese-based oxide represented by the following chemical formula 4A, or a combination thereof.

[0086] [Chemical Formula 1A]

[0087] Li a1 Ni x1 M 1 y1 M 2 z1 O 2-b1 X b1

[0088] In the above chemical formula 1A, 0.9≤a1≤1.8, 0.3≤x1≤1, 0≤y1≤0.7, 0≤z1≤0.7, 0.9≤x1+y1+z1≤1.1, and 0≤b1≤0.1, and M 1 and M 2 are each independently Al, B, Ba, Ca, Ce, Co, Cr, Cu, Fe, Mg, Mn, Mo, Nb, Si, Sn, Sr, Ti, V, W, Zr, or a combination thereof, and X is F, P, S, or a combination thereof.

[0089] In the above chemical formula 1A, 0.6≤x1≤1, 0≤y1≤0.4, and 0≤z1≤0.4, or 0.8≤x1≤1, 0≤y1≤0.2, and 0≤z1≤0.2.

[0090] [Chemical Formula 2A]

[0091] Li a2 Co x2 M 3 y2 O 2-b2 X b2

[0092] In the above chemical formula 2A, 0.9≤a2≤1.8, 0.7≤x2≤1, 0≤y2≤0.3, 0.9≤x2+y2≤1.1, and 0≤b2≤0.1, and M 3 is Al, B, Ba, Ca, Ce, Cr, Cu, Fe, Mg, Mn, Mo, Ni, Se, Si, Sn, Sr, Ti, V, W, Y, Zn, Zr, or a combination thereof, and X is F, P, S, or a combination thereof.

[0093] [Chemical Formula 3A]

[0094] Li a3 Fe x3 M 4 y3 PO 4-b3 X b3

[0095] In the above chemical formula 3A, 0.9≤a3≤1.8, 0.6≤x3≤1, 0≤y3≤0.4, and 0≤b3≤0.1, and M 4is Al, B, Ba, Ca, Ce, Co, Cr, Cu, Mg, Mn, Mo, Ni, Se, Si, Sn, Sr, Ti, V, W, Y, Zn, Zr, or a combination thereof, and X is F, P, S, or a combination thereof.

[0096] [Chemical Formula 4A]

[0097] Li a4 Ni x4 Mn y4 M 5 z4 O 2-b4 X b4

[0098] In the above chemical formula 4A, 0.9≤a2≤1.8, 0.8≤x4<1, 0 <y4≤0.2, 0≤z4≤0.2, 0.9≤x4+y4+z4≤1.1, 및 0≤b4≤0.1이고 M 5 is Al, B, Ba, Ca, Ce, Cr, Fe, Mg, Mo, Nb, Si, Sn, Sr, Ti, V, W, Zr, or a combination thereof, and X is F, P, S, or a combination thereof.

[0099] The above positive electrode active material may be in the form of particles, and the average particle diameter (D) of the positive electrode active material 50 ) may be 1 ㎛ to 25 ㎛, for example, 3 ㎛ to 25 ㎛, 1 ㎛ to 20 ㎛, 1 ㎛ to 18 ㎛, 3 ㎛ to 15 ㎛, or 5 ㎛ to 15 ㎛. For example, the positive electrode active material may have an average particle diameter (D 50 ) with small particles of 1 ㎛ to 9 ㎛ and an average particle diameter (D 50) may include particles having a particle size range of 10 ㎛ to 25 ㎛. The positive electrode active material having such a particle size range can be harmoniously mixed with other components in the positive electrode active material layer and can realize high capacity and high energy density. Here, the average particle size is obtained by selecting 20 random particles from a scanning electron microscope image of the positive electrode active material, measuring the particle size (diameter, or major axis, or major axis length), and then obtaining a particle size distribution, and in the particle size distribution, the diameter (D) of the particles having a cumulative volume of 50% by volume 50 ) may be taken as the average particle diameter.

[0100] The above-mentioned positive electrode active material may be in the form of a secondary particle formed by agglomeration of a plurality of primary particles, or may be in the form of a single particle. In addition, the above-mentioned positive electrode active material may be spherical or nearly spherical in shape, or may be polyhedral or irregular in shape.

[0101] Meanwhile, the positive electrode active material may include a buffer layer on the particle surface. The buffer layer may be expressed as a coating layer, a protective layer, etc., and may play a role in lowering the interfacial resistance between the positive electrode active material and the solid electrolyte particles. For example, the buffer layer may include a lithium-metal-oxide, wherein the metal may be, for example, Al, B, Ca, Ce, Cr, Fe, Mg, Mo, Nb, Si, Sn, Sr, Ta, V, W, Zr, or a combination thereof. The lithium-metal-oxide is excellent in lowering the interfacial resistance between the positive electrode active material and the solid electrolyte particles by facilitating the movement of lithium ions and electron conduction, thereby improving the performance of the positive electrode active material.

[0102] The positive electrode active material may be included in an amount of 55 wt% to 99 wt% based on 100 wt% of the positive electrode active material layer, for example, 65 wt% to 95 wt%, or 75 wt% to 95 wt%.

[0103] solid electrolyte

[0104] The solid electrolyte included in the positive electrode active material layer may include an inorganic solid electrolyte. The inorganic solid electrolyte may include, for example, a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a halide-based solid electrolyte, or a combination thereof. A representative example of the inorganic solid electrolyte may include a sulfide-based solid electrolyte, and in addition to the sulfide-based solid electrolyte, the solid electrolyte may further include an oxide-based solid electrolyte, a halide-based solid electrolyte, or a combination thereof. The description given below with respect to the solid electrolyte layer may be equally applied to the solid electrolyte included in the positive electrode active material layer.

[0105] With respect to 100 wt% of the above positive electrode active material layer, the solid electrolyte may be included in an amount of 0.1 wt% to 35 wt%, for example, 1 wt% to 35 wt%, 5 wt% to 30 wt%, 8 wt% to 25 wt%, or 10 wt% to 20 wt%.

[0106] In addition, in the positive electrode active material layer, 65 wt% to 99 wt% of the positive electrode active material and 1 wt% to 35 wt% of the solid electrolyte may be included based on the total weight of the positive electrode active material and the solid electrolyte, for example, 80 wt% to 90 wt% of the positive electrode active material and 10 wt% to 20 wt% of the solid electrolyte may be included. When the solid electrolyte is included in the positive electrode in such an amount, the efficiency and life characteristics of the all-solid-state battery can be improved without reducing the capacity.

[0107] bookbinder

[0108] The above binder serves to adhere positive electrode active material particles well to each other and also to adhere positive electrode active material well to a current collector, and representative examples thereof include, but are not limited to, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers containing ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin, nylon, etc.

[0109] The content of the binder in the positive electrode active material layer may be approximately 0.1 wt% to 5 wt% with respect to 100 wt% of the positive electrode active material layer.

[0110] Challenge

[0111] The above-described positive electrode active material layer may further include a conductive material. The conductive material is used to provide conductivity to the electrode, and any material that does not cause a chemical change and is electronically conductive in the battery to be formed may be used. Examples of conductive materials that may be used include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, carbon nanotube, etc.; metal-based materials containing copper, nickel, aluminum, silver, etc. in the form of metal powder or metal fiber; conductive polymers such as polyphenylene derivatives; or conductive materials including mixtures thereof.

[0112] The content of the conductive material in the positive electrode active material layer may be 0 wt% to 3 wt%, 0.01 wt% to 2 wt%, or 0.1 wt% to 1 wt% with respect to 100 wt% of the positive electrode active material layer.

[0113] Aluminum foil may be used as the positive electrode current collector, but is not limited thereto.

[0114] cathode

[0115] The negative electrode of the all-solid-state secondary battery according to one embodiment may be a precipitation-type negative electrode, as described above. The precipitation-type negative electrode may refer to a negative electrode that does not include a negative electrode active material when the battery is assembled, but in which lithium metal or the like is precipitated or deposited on the negative electrode when the battery is charged, and this acts as a negative electrode active material.

[0116] Fig. 2 is a schematic cross-sectional view of an all-solid-state secondary battery including a precipitated negative electrode. Referring to Fig. 2, the precipitated negative electrode (400') may include a negative electrode current collector (401) and a negative electrode coating layer (405) positioned on the negative electrode current collector. Here, the negative electrode current collector (401) may be the patterned negative electrode current collector (41) described above. An all-solid-state secondary battery including such a precipitated negative electrode (400') starts initial charging in a state in which no negative electrode active material is present. Next, during charging, high-density lithium metal may be deposited or electrodeposited between the negative electrode current collector (401) and the negative electrode coating layer (405), or on the negative electrode coating layer (405), so that electrodeposited lithium (or lithium-containing layer) may be formed in the groove (12) of the patterned negative electrode current collector (41) as described above, and / or a lithium metal layer (404) may be formed as shown in FIG. 2, which may serve as the negative electrode active material. Accordingly, in an all-solid-state secondary battery that has been charged more than once, a deposited negative electrode (400') may include, for example, a negative electrode current collector (401), a lithium metal layer (404) positioned on the negative electrode current collector, and a negative electrode coating layer (405) positioned on the lithium metal layer. The lithium metal layer (404) refers to a layer in which lithium metal, etc. is deposited during the charging process of the battery, and may be referred to as a metal layer, a lithium layer, a lithium electrodeposition layer, or a negative electrode active material layer. At this time, the negative electrode current collector (401) illustrated in FIG. 2 may be a patterned negative electrode current collector (41) as illustrated in FIG. 5.

[0117] The above cathode coating layer (405) may be referred to as a lithium electrodeposition induction layer or a cathode catalyst layer, and may include a lithium-philic metal, a carbon material, or a combination thereof.

[0118] The above lithium-philic metal may include, for example, gold, platinum, palladium, silicon, silver, aluminum, bismuth, tin, zinc, or a combination thereof, and may be composed of one type of these or may be composed of several types of alloys. When the metal is present in the form of particles, the average particle diameter (D 50 ) may be less than about 4 μm, for example, 10 nm to 4 μm.

[0119] The carbon material may be, for example, crystalline carbon, amorphous carbon, or a combination thereof. The crystalline carbon may be, for example, natural graphite, artificial graphite, mesophase carbon microbeads, or a combination thereof. The amorphous carbon may be, for example, carbon black, activated carbon, acetylene black, Denka black, Ketjen black, or a combination thereof.

[0120] When the above-described negative electrode coating layer (405) includes both the metal and the carbon material, the mixing ratio of the metal and the carbon material may be, for example, a weight ratio of 1:10 to 2:1. In this case, the precipitation of lithium metal can be effectively promoted and the characteristics of the all-solid-state secondary battery can be improved. The negative electrode coating layer (405) may include, for example, a carbon material supported with a catalytic metal, or may include a mixture of metal particles and carbon material particles.

[0121] The above-described cathode coating layer (405) may include, for example, the above-described lithium-philic metal and amorphous carbon, in which case the precipitation of the lithium metal may be effectively promoted. As a specific example, the cathode coating layer (405) may include a composite in which a lithium-philic metal is supported on amorphous carbon.

[0122] The above cathode coating layer (405) may further include a binder, and the binder may be, for example, a conductive binder. In addition, the above cathode coating layer (405) may further include general additives such as fillers, dispersants, and ionic conductive agents.

[0123] The thickness of the cathode coating layer (405) may be, for example, 100 nm to 20 μm, or 500 nm to 10 μm, or 1 μm to 5 μm.

[0124] The above-described precipitated negative electrode (400') may further include, for example, a thin film on the surface of the negative electrode current collector, that is, between the negative electrode current collector and the negative electrode coating layer. The thin film may include an element capable of forming an alloy with lithium. The element capable of forming an alloy with lithium may be, for example, gold, silver, zinc, tin, indium, silicon, aluminum, bismuth, etc., and may be composed of one type thereof or may be composed of multiple types of alloys. The thin film may further flatten the precipitated form of the lithium metal layer (404) and further improve the characteristics of the all-solid-state secondary battery. The thin film may be formed by, for example, a vacuum deposition method, a sputtering method, a plating method, etc. The thickness of the thin film may be, for example, 1 nm to 500 nm.

[0125] The lithium metal layer (404) may include lithium metal or a lithium alloy. The lithium alloy may be, for example, a Li-Al alloy, a Li-Sn alloy, a Li-In alloy, a Li-Ag alloy, a Li-Au alloy, a Li-Zn alloy, a Li-Ge alloy, or a Li-Si alloy.

[0126] The thickness of the lithium metal layer (404) may be 1 µm to 500 µm, 1 µm to 200 µm, 1 µm to 100 µm, or 1 µm to 50 µm. Within the above range, the lithium storage layer can sufficiently perform its role and prevent performance degradation due to an increase in battery volume.

[0127] When such a precipitation-type negative electrode is applied, the negative electrode coating layer (405) can protect the electrodeposited lithium (or lithium-containing layer) or lithium metal layer (404) located within the groove (12) of the patterned negative electrode collector (41), while suppressing the precipitation growth of lithium deadlight. Accordingly, short-circuiting and capacity reduction of the all-solid-state battery can be suppressed, and the life characteristics can be improved.

[0128] The negative electrode current collector may include a copper foil, a nickel foil, a stainless steel foil, a titanium foil, a nickel foam, a copper foam, a polymer substrate coated with a conductive metal, or a combination thereof.

[0129] solid electrolyte layer

[0130] In an all-solid-state secondary battery according to one embodiment, a solid electrolyte layer (300) may be positioned between a positive electrode (200) and a negative electrode (400). The solid electrolyte layer (300) may include an inorganic solid electrolyte as a solid electrolyte, and the inorganic solid electrolyte may include a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a halide-based solid electrolyte, or a combination thereof. As a representative example, the inorganic solid electrolyte may include a sulfide-based solid electrolyte, and in addition, may further include a solid electrolyte selected from an oxide-based solid electrolyte, a halide-based solid electrolyte, or a combination thereof.

[0131] Sulfide-based solid electrolyte

[0132] For example, the solid electrolyte layer (300) may include a sulfide-based solid electrolyte having excellent ion conductivity. The sulfide-based solid electrolyte may include, for example, Li2S-P2S5, Li2S-P2S5-LiX (wherein X is a halogen element, for example, I or Cl), Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z m S n (m, n are integers, Z is Ge, Zn or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q (p, q are integers, and M is P, Si, Ge, B, Al, Ga or In), or a combination thereof.

[0133] Such sulfide-based solid electrolytes can be obtained, for example, by mixing Li2S and P2S5 in a molar ratio of 50:50 to 90:10, or 50:50 to 80:20, and optionally heat-treating them. Within the above mixing ratio range, a sulfide-based solid electrolyte having excellent ionic conductivity can be produced. Here, the ionic conductivity can be further improved by further including other components such as SiS2, GeS2, and B2S3.

[0134] Methods for mixing sulfur-containing raw materials for producing sulfide-based solid electrolytes include mechanical milling or the solution method. Mechanical milling involves placing raw materials in a ball mill reactor and vigorously stirring them to finely atomize and mix them. Using the solution method, the raw materials are mixed in a solvent to obtain a solid electrolyte as a precipitate. Furthermore, heat treatment after mixing can solidify the crystals of the solid electrolyte and improve ionic conductivity. For example, a sulfide-based solid electrolyte can be produced by mixing sulfur-containing raw materials and heat-treating them twice or more, resulting in a sulfide-based solid electrolyte with high ionic conductivity and robustness.

[0135] According to one embodiment, a sulfide-based solid electrolyte can be manufactured through, for example, a first heat treatment in which sulfur-containing raw materials are mixed and calcined at 120°C to 350°C, and a second heat treatment in which the first heat treatment result is mixed and calcined at 350°C to 800°C. The first heat treatment and the second heat treatment can each be performed in an inert gas or nitrogen atmosphere. The first heat treatment can be performed for 1 to 10 hours, and the second heat treatment can be performed for 5 to 20 hours. The first heat treatment can have the effect of milling small raw materials, and the second heat treatment can synthesize the final solid electrolyte. Through two or more such heat treatments, a high-performance sulfide-based solid electrolyte with high ionic conductivity and robustness can be obtained, and such a solid electrolyte can be said to be suitable for mass production. The temperature of the first heat treatment may be, for example, 150°C to 330°C, or 200°C to 300°C, and the temperature of the second heat treatment may be, for example, 380°C to 700°C, or 400°C to 600°C.

[0136] For example, the sulfide-based solid electrolyte may be in the form of particles and may include argyrodite-type sulfides. These argyrodite-type sulfide-based solid electrolyte particles have an ionic conductivity of 10, which is the ionic conductivity of a typical liquid electrolyte at room temperature. -4 10 inland -2 It possesses high ionic conductivity approaching the S / cm range. Furthermore, it can form a close bond between the positive electrode active material and the solid electrolyte without causing a decrease in ionic conductivity, and can form a close interface between the electrode and the solid electrolyte layer. An all-solid-state secondary battery including this can exhibit improved battery performance, such as rate characteristics, Coulombic efficiency, and cycle life characteristics.

[0137] The above sulfide-based solid electrolyte may include, for example, an argyrodite-type sulfide represented by the chemical formula 1B below.

[0138] [Chemical Formula 1B]

[0139] (Li a M 1 b M 2 c )(P d M 3 e )(S f M 4 g )X h

[0140] In the above chemical formula 1B, 4≤a≤8, and M 1 is Mg, Cu, Ag, or a combination thereof, and 0≤b<0.5, and M 2 is Na, K, or a combination thereof, 0≤c<0.5, and M 3 is Sn, Zn, Si, Sb, Ge, or a combination thereof, and 0 <d<4, 0≤e<1 이고, M 4 is O, SO n , or a combination thereof, and 1.5≤n≤5, 3≤f≤12, 0≤g<2, and X is F, Cl, Br, I, or a combination thereof, and 0≤h≤2.

[0141] For example, in chemical formula 1B, a halogen element (X) may be included as an essential element, in which case 0 <h≤2로 표시될 수 있다. 일 예로 화학식 1B에 M 1 Elements may be required, in which case 0 <b<0.5로 표시될 수 있다. 화학식 1B에서 M 3 can be understood as an element substituted in the P position, and 0 <e<1일 수 있다. 화학식 1B에서 M 4 is substituted in the S position, for example, 0 <g<2일 수 있으며, S의 비율인 f는 예를 들어 3≤f≤7일 수 있다. M 4 Go SO n If SO n It can be, for example, S4O6, S3O6, S2O3, S2O4, S2O5, S2O6, S2O7, S2O8, SO4, or SO5, and can be, for example, SO4.

[0142] For example, in Chemical Formula 1B, a+b+c+h=7, d+e=1, and f+g+h=6.

[0143] As a specific example, argyrodite-type sulfide-based solid electrolyte particles include Li3PS4 and Li7P3S. 11 , Li7PS6, Li6PS5Cl, Li6PS5Br, Li 5.8 PS 4.8 Cl 1.2 , Li 6.2 PS 5.2 Br 0.8 , Li 5.75 PS 4.75 Cl 1.25 , (Li 5.69 Cu 0.06 )PS 4.75 Cl 1.25 , (Li 5.72 Cu 0.03 )PS 4.75 Cl 1.25 , (Li 5.69 Cu 0.06 )P(S 4.70 (SO4) 0.05 )Cl 1.25 , (Li 5.69 Cu0.06 )P(S 4.60 (SO4) 0.15 )Cl 1.25 , (Li 5.72 Cu 0.03 )P(S 4.725 (SO4) 0.025 )Cl 1.25 , (Li 5.72 Na 0.03 )P(S 4.725 (SO4) 0.025 )Cl 1.25 , Li 5.75 P(S 4.725 (SO4) 0.025 )Cl 1.25 , or combinations thereof, but are not limited thereto.

[0144] An argyrodite-type sulfide-based solid electrolyte can be manufactured, for example, by mixing lithium sulfide and phosphorus sulfide, and optionally, lithium halide. After mixing these, a heat treatment may be performed. The heat treatment may include, for example, two or more heat treatment steps. Here, manufacturing an argyrodite-type sulfide-based solid electrolyte may include, for example, a first heat treatment of mixing raw materials and calcining at 120°C to 350°C, and a second heat treatment of mixing the resultant of the first heat treatment again and calcining at 350°C to 800°C.

[0145] Average particle diameter (D) of sulfide-based solid electrolyte particles 50 ) may be, for example, 0.1 ㎛ to 5.0 ㎛ or 0.1 ㎛ to 3.0 ㎛, may be small particles of 0.1 ㎛ to 1.9 ㎛, or may be large particles of 2.0 ㎛ to 5.0 ㎛. The sulfide-based solid electrolyte particles may be a mixture of small particles having an average particle diameter of 0.1 ㎛ to 1.9 ㎛ and large particles having an average particle diameter of 2.0 ㎛ to 5.0 ㎛. The average particle diameter of the sulfide-based solid electrolyte particles may be measured by an electron microscope image, and for example, a particle size distribution is obtained by measuring the size (diameter or major axis length) of about 20 particles in a scanning electron microscope image, where D50 It may have been calculated.

[0146] For example, the sulfide-based solid electrolyte may be included in an amount of 80 wt% to 97 wt% based on 100 wt% of the solid electrolyte layer, for example, 85 wt% to 97 wt%, 90 wt% to 97 wt%, 93 wt% to 97 wt%, or 94 wt% to 96 wt%. Within this range, excellent ionic conductivity can be secured while ensuring the durability of the battery.

[0147] Oxide-based solid electrolyte

[0148] The solid electrolyte layer (300) may include an oxide-based solid electrolyte. The oxide-based solid electrolyte may be, for example, Li 1+x Ti 2-x Al(PO4)3(LTAP)(0≤x≤4), Li 1+x+y Al x Ti 2-x Si y P 3-y O 12 (0 <x<2, 0≤y<3), BaTiO3, Pb(Zr,Ti)O3(PZT), Pb 1-x La x Zr 1-y Ti y O3(PLZT)(0≤x<1, 0≤y<1), PB(Mg3Nb 2 / 3 )O3-PbTiO3(PMN-PT), HfO2, SrTiO3, SnO2, CeO2, Na2O, MgO, NiO, CaO, BaO, ZnO, ZrO2, Y2O3, Al2O3, TiO2, SiO2, lithium phosphate (Li3PO4), lithium titanium phosphate (Li x Ti y (PO4)3, 0 <x<2, 0<y<3), Li 1+x+y (Al, Ga) x (Ti, Ge) 2-x Si y P 3-y O 12 (0≤x≤1, 0≤y≤1), lithium lanthanum titanate (Li x Lay TiO3, 0 <x<2, 0<y<3), Li2O, LiAlO2, Li2O-Al2O3-SiO2-P2O5-TiO2-GeO2계 세라믹스, 가넷(Garnet)계 세라믹스 Li 3+x La3M2O 12 (M= Te, Nb, or Zr; x is an integer from 1 to 10), or mixtures thereof.

[0149] Halide-based solid electrolyte

[0150] The solid electrolyte layer (300) may include, for example, a halide-based solid electrolyte. The halide-based solid electrolyte contains a halogen element as a main component, and may mean that the ratio of the halogen element to all elements constituting the solid electrolyte is 50 mol% or more, 70 mol% or more, 90 mol% or more, or 100 mol%. For example, the halide-based solid electrolyte may not contain a sulfur element.

[0151] The halide-based solid electrolyte may contain lithium element, a metal element other than lithium, and a halogen element. The metal element other than lithium may be Al, As, B, Bi, Ca, Cd, Co, Cr, Fe, Ga, Hf, In, Mg, Mn, Ni, Sb, Sc, Sn, Ta, Ti, Y, Zn, Zr, or a combination thereof. The halogen element may be F, Cl, Br, I, or a combination thereof, and may be Cl, Br, or a combination thereof. The halide-based solid electrolyte may contain, for example, Li a M1X6 (M is Al, As, B, Bi, Ca, Cd, Co, Cr, Fe, Ga, Hf, In, Mg, Mn, Ni, Sb, Sc, Sn, Ta, Ti, Y, Zn, Zr, or a combination thereof, X is F, Cl, Br, I, or a combination thereof, and 2≤a≤3) can be represented. The halide-based solid electrolyte may be, for example, Li2ZrCl6, Li 2.7 Y0.7 Zr 0.3 Cl6, Li 2.5 Y 0.5 Zr 0.5 Cl6, Li 2.5 In 0.5 Zr 0.5 Cl6, Li2In 0.5 Zr 0.5 Cl6, Li3YBr6, Li3YCl6, Li3YBr2Cl4, Li3YbCl6, Li 2.6 Hf 0.4 Yb 0.6 Cl6, or combinations thereof, but is not limited thereto.

[0152] bookbinder

[0153] The solid electrolyte layer according to one embodiment may further include a binder. Binders include, for example, nitrile-butadiene rubber, hydrogenated nitrile-butadiene rubber, styrene-butadiene rubber, acrylated styrene-butadiene rubber, acrylonitrile-butadiene rubber, acrylic rubber, butyl rubber, fluoroelastomer, natural rubber, polydimethylsiloxane, polyethylene oxide, polyvinylpyrrolidone, polyvinylpyridine, chlorosulfonated polyethylene, polyvinyl alcohol, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-propylene-diene copolymer, polyamideimide, polyimide, poly(meth)acrylate, polyacrylonitrile, polystyrene, polyurethane, and the like. copolymers, or combinations thereof.

[0154] The binder may be included in an amount of 0.1 wt% to 3 wt% based on 100 wt% of the solid electrolyte layer, for example, 0.5 wt% to 2 wt%, or 0.5 wt% to 1.5 wt%. When the binder is included in the above range, the components within the solid electrolyte layer can be well combined without lowering the ionic conductivity of the solid electrolyte, thereby improving the durability and reliability of the battery.

[0155] Other ingredients

[0156] The solid electrolyte layer may optionally further include other components such as alkali metal salts, and / or ionic liquids, and / or conductive polymers.

[0157] The above alkali metal salt may be, for example, a lithium salt. The content of the lithium salt in the solid electrolyte layer may be 1 M or more, for example, 1 M to 4 M. In this case, the lithium salt may improve ion conductivity by enhancing the lithium ion mobility of the solid electrolyte layer.

[0158] The lithium salt may be applied without limitation on type, and may include, for example, LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiAlO2, LiAlCl4, LiPO2F2, LiCl, LiI, LiSCN, LiN(CN)2, lithium bis(oxalato)borate (LiBOB), lithium difluoro(oxalato)borate (LiDFOB), lithium difluorobis(oxalato)phosphate (LiDFBP), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(pentafluoroethanesulfonyl)imide (LiBETI), lithium trifluoromethanesulfonate, lithium tetrafluoroethanesulfonate, or a combination thereof.

[0159] For example, the lithium salt may be an imide-based lithium salt such as LiTFSI, LiFSI, LiBETI, or a combination thereof. The imide-based lithium salt can maintain or improve ionic conductivity by appropriately maintaining chemical reactivity with the ionic liquid.

[0160] Ionic liquids are salts or molten salts that are composed only of ions and are liquid at room temperature, with a melting point below room temperature.

[0161] The ionic liquid comprises a) one or more cations selected from ammonium, pyrrolidinium, pyridinium, pyrimidinium, imidazolium, piperidinium, pyrazolium, oxazolium, pyridazinium, phosphonium, sulfonium, triazolium, and mixtures thereof, and b) BF4. - , PF6 - , AsF6 - , SbF6 - , AlCl4 - , HSO4 - , ClO4 - , CH3SO3 - , CF3CO2 - , Cl - , Br - , I - , BF4 - , SO4 - , CF3SO3 - , (FSO2)2N - , (C2F5SO2)2N - , (C2F5SO2)(CF3SO2)N - , and (CF3SO2)2N - It may be a compound containing one or more anions selected from among.

[0162] The ionic liquid may include, for example, N-methyl-N-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide, N-butyl-N-methylpyrrolidinium bis(3-trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide, or a combination thereof.

[0163] In the above solid electrolyte layer, the weight ratio of the solid electrolyte and the ionic liquid may be 0.1:99.9 to 90:10, for example, 10:90 to 90:10, 20:80 to 90:10, 30:70 to 90:10, 40:60 to 90:10, or 50:50 to 90:10. A solid electrolyte layer satisfying the above range can maintain or improve ionic conductivity by improving the electrochemical contact area with the electrode. Accordingly, the energy density, discharge capacity, rate characteristics, etc. of the all-solid-state secondary battery can be improved.

[0164] The shape of the above-mentioned all-solid-state secondary battery is not particularly limited, and may be, for example, coin-shaped, button-shaped, sheet-shaped, stacked, cylindrical, flat, etc. In addition, the above-mentioned all-solid-state secondary battery can be applied to large-scale batteries used in electric vehicles, etc. For example, the above-mentioned all-solid-state secondary battery can be used in hybrid vehicles such as plug-in hybrid electric vehicles (PHEVs). In addition, it can be used in fields requiring a large amount of power storage, and for example, it can be used in electric bicycles or power tools, etc. In addition, the above-mentioned all-solid-state secondary battery can be used in various fields such as portable electronic devices.

[0165] Hereinafter, examples and comparative examples of the present invention are described. The following examples are merely examples of the present invention, and the present invention is not limited to the following examples.

[0166] Example 1

[0167] A nickel foil current collector having a thickness of 80 μm patterned to include a base portion, a protrusion portion protruding from the base portion, and a groove portion set between adjacent protrusion portions, wherein the width (L) of the protrusion portion is 20 μm, the width (W) of the groove portion is 40 μm, and the depth (H) of the groove portion is 25 μm was prepared.

[0168] At this time, the grooves and protrusions of the patterned nickel foil collector formed a lattice structure with respect to the plane of the base portion, and the shapes of the grooves and protrusions were square with respect to the cross-section of the patterned nickel foil collector.

[0169] Primary entry (D 50 ) carbon black with an average particle diameter (D) of about 30 nm 50 ) was prepared by mixing silver (Ag) of about 60 nm in a weight ratio of 3:1, and 0.25 g of the above complex was added to 2 g of an NMP solution containing 7 wt% of polyvinylidene fluoride binder (PVDF) and mixed to prepare a cathode coating layer composition.

[0170] Next, the above-described negative electrode coating layer composition was applied onto the patterned nickel foil current collector using a bar coater and vacuum-dried to prepare a deposition-type negative electrode in which a negative electrode coating layer was formed on the patterned negative electrode current collector.

[0171] Afterwards, an argyrodite-type solid electrolyte Li6PS5Cl(D) was added to a binder solution in which an acrylic binder (SX-A334, Zeon) was dissolved in an isobutyl isobutyrate (IBIB) solvent. 50 =3㎛) was added and stirred to prepare a slurry for forming a solid electrolyte layer. The slurry for forming a solid electrolyte layer contained 98.5 wt% of a solid electrolyte and 1.5 wt% of a binder. The slurry for forming a solid electrolyte layer was applied on a release PET film using a bar coater, dried at room temperature, and pelletized by uniaxial pressing at 500 MPa to prepare a solid electrolyte layer having a thickness of 590 ㎛.

[0172] The prepared negative electrode, solid electrolyte layer, and positive electrode, which is a lithium (Li) metal counter electrode, were cut and laminated to manufacture a laminate, and then the final all-solid-state secondary battery in the form of a half-cell was manufactured by uniaxially pressing at 20 MPa at 25°C, and the current density was 0.1 mA / cm at 25°C. 2 The electrodeposited lithium was formed on the patterned negative electrode collector by driving for 1 hour at a working current density of .

[0173] Example 2

[0174] An all-solid-state secondary battery was manufactured in substantially the same manner as in Example 1, except that the all-solid-state secondary battery was placed in an oven and current was applied to change the operating temperature to 60°C, and the battery was operated to form electrodeposited lithium on the patterned negative electrode collector.

[0175] Example 3

[0176] In the above Example 1, the all-solid-state secondary battery was placed in an oven and current was applied to change the operating temperature to 60°C and the operating current density to 1.0 mA / cm 2 An all-solid-state secondary battery was manufactured and operated in substantially the same manner as in Example 1, except that the operating time was changed to 6 minutes, thereby forming electrodeposited lithium on the patterned negative electrode collector.

[0177] Example 4

[0178] An all-solid-state secondary battery was manufactured in substantially the same manner as in Example 1, except that the pressure of the uniaxial pressing on the laminate in Example 2 was changed to 5 MPa, and the battery was operated to form electrodeposited lithium on the patterned negative electrode collector.

[0179] Reference Example 1

[0180] An all-solid-state secondary battery was manufactured and operated in substantially the same manner as in Example 1, except that the laminate was not pressurized (i.e., the pressure of uniaxial pressing on the laminate was 0 MPa), thereby forming electrodeposited lithium on the patterned negative electrode collector.

[0181] Reference Example 2

[0182] An all-solid-state secondary battery was manufactured and operated in substantially the same manner as in Example 1, except that the pressure of the uniaxial pressing on the laminate in Example 1 was changed to 5 MPa, thereby forming electrodeposited lithium on the patterned negative electrode collector.

[0183] Comparative Example 1

[0184] An all-solid-state secondary battery was manufactured in substantially the same manner as in Example 1, except that a flat negative electrode collector, nickel foil, was used instead of a patterned negative electrode collector in Example 1, and the battery was operated to form electrodeposited lithium on the negative electrode collector.

[0185] Reference Example 3

[0186] An all-solid-state secondary battery was manufactured and operated in substantially the same manner as in Example 1, except that the laminate was not pressurized in Example 2 (i.e., the pressure of uniaxial pressing on the laminate corresponded to 0 MPa), to form electrodeposited lithium on the patterned negative electrode collector.

[0187] Reference Example 4

[0188] An all-solid-state secondary battery was manufactured and operated in substantially the same manner as in Example 1, except that in Example 3, no pressure was applied to the laminate (i.e., the pressure of the uniaxial pressing on the laminate corresponded to 0 MPa), thereby forming electrodeposited lithium on the patterned negative electrode collector.

[0189] Reference Example 5

[0190] An all-solid-state secondary battery was manufactured in substantially the same manner as in Example 1, except that the pressure of the uniaxial pressing on the laminate in Example 3 was changed to 5 MPa, and the battery was operated to form electrodeposited lithium on the patterned negative electrode collector.

[0191] Comparative Example 2

[0192] An all-solid-state secondary battery was manufactured in substantially the same manner as in Example 1, except that a flat negative electrode collector, nickel foil, was used instead of the patterned negative electrode collector in Example 3, and the battery was operated to form electrodeposited lithium on the negative electrode collector.

[0193] Comparative Example 3

[0194] An all-solid-state secondary battery was manufactured in substantially the same manner as in Example 1, except that a flat negative electrode collector, nickel foil, was used instead of the patterned negative electrode collector in Example 3, and the battery was operated to form electrodeposited lithium on the negative electrode collector.

[0195] Evaluation Example 1: Pressure Gradient Evaluation

[0196] In order to evaluate the effect of the shape of the patterned negative current collector on the pressure gradient in the solid electrolyte layer for an all-solid-state secondary battery, an electrochemical analyzer (manufacturer: Biologic, model name: VSP potentiostat system) was used and a simulation evaluation was performed using COMSOL Multiphysics version 5.6. At this time, the pressure gradient results in the solid electrolyte layer measured while changing the pressure during pressurization to 5 MPa, 10 MPa, 20 MPa, and 30 MPa for the laminates manufactured in Example 1 and Comparative Example 1 are shown in FIGS. 7 and 8, respectively.

[0197] Referring to Fig. 8, in the case of Comparative Example 1, it can be confirmed that the solid electrolyte layer located between the two flat electrodes, the positive electrode and the negative electrode, exhibits a uniform hydrostatic pressure distribution regardless of the external pressure. On the other hand, referring to Fig. 7, in the case of Example 1, it can be confirmed that the solid electrolyte layer located between the positive electrode, which is a flat electrode, and the negative electrode, which is a patterned electrode, exhibits an uneven pressure distribution at the interface with the negative electrode, which is a patterned electrode, and it can be confirmed that this becomes stronger as the lamination pressure increases. Accordingly, it can be confirmed that the local pressure in the area corresponding to the protrusion (11) is higher than the local pressure in the area corresponding to the groove (12), and it can be confirmed that a pressure gradient is formed from the protrusion to the groove.

[0198] Evaluation Example 2: Ion current flux and scanning electron microscope (SEM) evaluation

[0199] In order to confirm the morphology of the electrodeposited lithium on the patterned negative electrode collector by operating the all-solid-state secondary batteries manufactured in Examples 1 to 4 and Reference Examples 1 to 5, the patterned negative electrode collector and the solid electrolyte layer were separated, and the interface on the patterned negative electrode collector side was photographed using a scanning electron microscope (SEM). In addition, the current density was simulated using COMSOL Multiphysics version 5.6 based on the standard shown in Fig. 20, and the ion current flux was simulated using COMSOL Multiphysics version 5.6 and represented as an arrow plot, and the results are shown in Figs. 11 to 19, respectively. At this time, the ion current flux results were Li in the solid electrolyte used, Li6PS5Cl. + Since is the only mobile charge, the ion current is Li + It is judged to be the same as the flux, and the lithium deposition morphology by the arrow plot of the ion current and the SEM photograph is compared to determine the Li according to the pressure gradient. +The change in flux distribution was evaluated. In addition, when displaying the ion current flux results, the protrusions (11) and grooves (12) of the patterned negative electrode collector are shown as representative in Fig. 11, and since Figs. 12 to 19 are the same as Fig. 11, the drawing symbols are omitted.

[0200] Referring to the scanning electron microscope (SEM) photographs of FIGS. 11 to 13, it can be confirmed that in the cases of Examples 1 to 3 in which a pressure of 20 MPa was applied to the laminate during the manufacturing process of the all-solid-state secondary battery, regardless of the operating temperature and operating current density, electrodeposited lithium (or a lithium-containing layer including electrodeposited lithium) was formed within the groove portion (12) of the patterned negative current collector at the interface between the patterned negative current collector and the solid electrolyte layer. In addition, referring to the ion current flux results of FIGS. 11 to 13, it can be seen that in the cases of Examples 1 to 3, ion current is concentrated in the groove portion (12) of the patterned negative current collector.

[0201] Also, referring to the scanning electron microscope (SEM) image of Fig. 14, in the case of Example 4, even though the operating temperature was as high as 60 ℃, the current density was 0.1 mA / cm 2 When the pressure is low, it can be confirmed that electrodeposited lithium (or a lithium-containing layer including electrodeposited lithium) is formed in the groove (12) of the patterned negative electrode collector at the interface between the patterned negative electrode collector and the solid electrolyte layer even when only 5 MPa of pressure is applied to the laminate during the manufacturing process of the all-solid-state secondary battery. In addition, referring to the ion current flux results of FIG. 14, it can be seen that in the case of Example 4, the ion current is concentrated in the groove (12) of the patterned negative electrode collector. This result indicates that as the operating temperature increases, the partial molar volume of lithium ions increases, resulting in the formation of Li by the pressure gradient. + It is believed that this is due to the strengthening of the flux.

[0202] Referring to the scanning electron microscope (SEM) photographs of FIGS. 15, 17, and 18, in the case of Reference Examples 1, 3, and 4, since no pressure was applied to the laminate during the manufacturing process of the all-solid-state secondary battery, it can be confirmed that the electrodeposited lithium (or the lithium-containing layer including the electrodeposited lithium) was formed on the protrusion (11), not in the groove (12) of the patterned negative current collector, at the interface between the patterned negative current collector and the solid electrolyte layer. In addition, referring to the ion current flux results of FIGS. 15, 17, and 18, it can be seen that in the case of Reference Examples 1, 3, and 4, the ion current is concentrated on the protrusion (11) of the patterned negative current collector, which is confirmed by the ion current appearing locally on the protrusion (11).

[0203] Referring to the scanning electron microscope (SEM) image of Fig. 16, in the case of Reference Example 2, the operating temperature is low at 25 ℃ and the current density is 0.1 mA / cm 2 When the pressure is low, even when a pressure of 5 MPa is applied to the laminate during the manufacturing process of the all-solid-state secondary battery, it can be confirmed that electrodeposited lithium (or a lithium-containing layer including electrodeposited lithium) is formed on the protrusion (11) of the patterned negative electrode collector, not within the groove (12) of the patterned negative electrode collector, at the interface between the patterned negative electrode collector and the solid electrolyte layer. In addition, referring to the ion current flux results of FIG. 16, it can be seen that in the case of Reference Example 2, the ion current is concentrated on the protrusion (11) of the patterned negative electrode collector.

[0204] Referring to the scanning electron microscope (SEM) image of Fig. 19, in the case of Reference Example 5, the operating temperature is as high as 60 ℃ and the current density is 1 mA / cm 2When the pressure is high, even when a pressure of 5 MPa is applied to the laminate during the manufacturing process of the all-solid-state secondary battery, it can be confirmed that electrodeposited lithium (or a lithium-containing layer including electrodeposited lithium) is formed on the protrusion (11) of the patterned negative electrode collector, not within the groove (12) of the patterned negative electrode collector, at the interface between the patterned negative electrode collector and the solid electrolyte layer. In addition, referring to the ion current flux results of FIG. 19, it can be seen that in the case of Reference Example 5, the ion current is concentrated on the protrusion (11) of the patterned negative electrode collector.

[0205] Evaluation Example 3: Internal Short Circuit Evaluation

[0206] When the all-solid-state secondary batteries manufactured in Examples 1 and 3, Reference Examples 1, 2, 4, and 5, and Comparative Examples 1 and 2 were driven under each driving condition, the voltage change according to the capacity was evaluated, and the results are shown in FIGS. 21 and 22. At this time, FIG. 21 shows the evaluation results for Example 1, Reference Examples 1 and 2, and Comparative Example 1, and FIG. 22 shows the evaluation results for Example 3, Reference Examples 4 and 5, and Comparative Example 2.

[0207] Referring to Fig. 21, it can be confirmed that in the case of Reference Examples 1 and 2 and Comparative Example 1, an internal short circuit occurs as the voltage moves from a specific capacity to 0V. On the other hand, in the case of Example 1, it can be confirmed that electrodeposited lithium is stably formed on the patterned negative electrode collector, and an internal short circuit does not occur.

[0208] Also, referring to Fig. 22, the driving temperature is changed to 60 ℃ and the operating current density is 1.0 mA / cm 2 Even if it is changed to , it can be seen that similar results to the above Fig. 9 are observed. That is, in the case of Reference Examples 4 and 5 and Comparative Example 2, it can be confirmed that an internal short circuit occurs by moving to OV at a certain capacity, and in particular, in the case of Comparative Example 2 using a flat negative electrode collector, the capacity is 3 mAh / cm 2It can be confirmed that an internal short circuit occurs before reaching the electrodeposition ...

[0209] By comparing the experimental results for Examples 1 and 3 and Comparative Examples 1 and 2, it can be seen that when a patterned negative electrode collector is used, the morphological instability associated with lithium electrodeposition can be effectively controlled compared to when a non-patterned, flat negative electrode collector is used.

[0210] Therefore, it can be seen that the pressure gradient and lithium ion gradient generated by the non-uniform interfacial contact due to the use of a patterned negative electrode collector can induce the formation of a lithium-containing layer containing stably deposited lithium within the grooves of the patterned negative electrode collector, thereby effectively preventing the occurrence of lithium dendrites.

[0211] Evaluation Example 4: SEM and BSE Evaluation

[0212] In the case where the all-solid-state secondary battery manufactured in Example 2 was driven to form electrodeposited lithium (or a lithium-containing layer) on a patterned negative electrode collector, the patterned negative electrode collector and the solid electrolyte layer were separated, and the interface on the solid electrolyte layer side was photographed using a scanning electron microscope (SEM) at different magnifications, as shown in FIGS. 23 and 24.

[0213] In addition, regarding the solid-state secondary battery manufactured in Example 2 in which electrodeposited lithium was formed on a patterned negative electrode collector, a photograph of the interface on the solid electrolyte layer side taken using back-scattered electrons (BSE) by separating the patterned negative electrode collector and the solid electrolyte layer is shown in Fig. 25.

[0214] Referring to FIGS. 23 to 25, it can be confirmed that the electrodeposited lithium (or lithium-containing layer) formed on the patterned negative electrode collector by operating the all-solid-state secondary battery manufactured in Example 2 is formed within the groove (12) of the patterned negative electrode collector (41).

[0215] Evaluation Example 5: Life Characteristics Evaluation

[0216] After driving the all-solid-state secondary batteries manufactured in Example 3 and Comparative Example 3 under each operating condition, 1.0 mA / cm 2 The results of measuring the voltage change according to the number of cycles by performing electrodeposition and de-electrodeposition with an electrodeposition capacity of 0.1 mA / h as one cycle are shown in Fig. 26.

[0217] In addition, the results of the voltage change according to the capacity in the first cycle in the above Fig. 26 are shown in Fig. 27, the results of the voltage change according to the capacity in the seventh cycle are shown in Fig. 28, and the results of the desorption capacity according to the number of cycles are shown in Fig. 29.

[0218] Referring to FIGS. 26 to 29, in the case of Comparative Example 3 using a flat cathode collector, a short circuit occurred in the 7th cycle, whereas in the case of Example 3, the lifespan characteristics were maintained until about the 28th cycle, which is longer than that, confirming that the lifespan characteristics were superior.

[0219] Although the preferred embodiments have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concepts defined in the following claims also fall within the scope of the present invention.

[0220] [Explanation of symbols]

[0221] 10: Base 11: Protrusion

[0222] 12: Home 20: Electrodeposited lithium (or lithium-containing layer)

[0223] 30: Lithium dendrite 41: Patterned negative electrode current collector

[0224] 100: All-solid-state secondary battery 200: Cathode

[0225] 201: Cathode current collector 203: Cathode active material layer

[0226] 300: solid electrolyte layer 400: cathode

[0227] 401: Negative current collector 403: Negative active material layer

[0228] 400': Precipitation type cathode 404: Lithium metal layer

[0229] 405: Cathode coating layer 500: Elastic sheet

Claims

1. Bipolar; cathode; and A solid electrolyte layer positioned between the positive electrode and the negative electrode and including an inorganic solid electrolyte; The above cathode is patterned cathode current collector; and An all-solid-state secondary battery comprising: an anode coating layer positioned on the patterned anode collector and including a lithium-philic metal, a carbon material, or a combination thereof.

2. In paragraph 1, The above patterned negative electrode collector bass section; A protrusion protruding from the above base portion; and An all-solid-state secondary battery comprising a groove portion set between adjacent protrusions.

3. In paragraph 1, An all-solid-state secondary battery further comprising a lithium-containing layer positioned within the home portion.

4. In paragraph 3, An all-solid-state secondary battery, wherein the lithium-containing layer comprises lithium metal or a lithium alloy.

5. In paragraph 1, An all-solid-state secondary battery further comprising a lithium metal layer formed by charging between the negative electrode current collector and the negative electrode coating layer.

6. In paragraph 5, An all-solid-state secondary battery wherein the lithium metal layer comprises lithium metal or a lithium alloy.

7. In paragraph 2, An all-solid-state secondary battery in which the above-mentioned groove portion and the above-mentioned protrusion portion form a lattice structure with respect to the plane of the base portion.

8. In paragraph 2, An all-solid-state secondary battery in which the shapes of the above-mentioned groove and the above-mentioned protrusion are square with respect to the cross-section of the above-mentioned negative electrode collector.

9. In paragraph 2, An all-solid-state secondary battery wherein the depth of the groove is 2 ㎛ to 60 ㎛.

10. In paragraph 2, An all-solid-state secondary battery wherein the width of the groove is 5 ㎛ to 70 ㎛.

11. In paragraph 2, An all-solid-state secondary battery wherein the width of the protrusion is 1 ㎛ to 50 ㎛.

12. In paragraph 1, An all-solid-state secondary battery wherein the thickness of the negative electrode collector is 5 ㎛ to 200 ㎛.

13. In paragraph 2, An all-solid-state secondary battery, wherein the ratio of the depth of the groove to the total thickness of the negative electrode collector is 10% to 90%.

14. In paragraph 1, An all-solid-state secondary battery wherein the negative electrode collector comprises a copper foil, a nickel foil, a lithium foil, a stainless steel foil, a titanium foil, a nickel foam, a copper foam, a polymer substrate coated with a conductive metal, or a combination thereof.

15. In paragraph 1, The above negative electrode collector is an all-solid-state secondary battery having a nickel foil.

16. Prepare a laminate including an anode; a cathode; and a solid electrolyte layer positioned between the anode and the cathode and including an inorganic solid electrolyte layer; Including pressurizing the above laminate, The above cathode is patterned cathode current collector; and A method for manufacturing an all-solid-state secondary battery, comprising: an anode coating layer positioned on the patterned anode collector and including a lithium-philic metal, a carbon material, or a combination thereof.

17. In paragraph 16, A method for manufacturing an all-solid-state secondary battery, wherein the pressure during pressurization is 5 MPa to 50 MPa.

18. In paragraph 16, A method for manufacturing an all-solid-state secondary battery, wherein the alignment of the laminate is adjusted through the pressurization.

19. In paragraph 16, Operating current density 0.05 mA / cm 2 Within 1.5 mA / cm 2 Adjust to the range, A method for manufacturing an all-solid-state secondary battery, wherein the operating temperature is controlled within a range of 20°C to 170°C.

20. In paragraph 16, A method for manufacturing an all-solid-state secondary battery satisfying at least one of the following conditions 1 and 2: Condition 1: The pressure during pressurization is 10 MPa to 50 MPa. Condition 2: The pressure during pressurization is 5 MPa or more and less than 10 MPa, the operating temperature is 45 ℃ to 100 ℃, and the operating current density is 0.1 mA / cm 2 Within 0.8 mA / cm 2 Being

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