All-solid-state batteries

Abstract

An all-solid-state battery includes a positive current collector, a positive active material layer disposed on the positive current collector and including a positive active material, a solid electrolyte layer disposed on the positive active material layer, a negative electrode disposed on the solid electrolyte layer, and a sacrificial positive electrode layer including a sacrificial active material and disposed between the positive current collector and the positive active material layer.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of priority to Korean Patent Application No. 10-2024-0176883, filed with the Korean Intellectual Property Office on December 2, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to all-solid-state batteries and methods for manufacturing the same, and more specifically, to all-solid-state batteries including a sacrificial cathode layer and methods for manufacturing the same. Background Technology

[0004] Rechargeable batteries are already used in smaller electronic devices, such as mobile phones or laptops, as well as larger transportation applications, such as hybrid and electric vehicles. Therefore, these expanding applications have created a demand for rechargeable batteries with higher stability and energy density.

[0005] Traditional rechargeable batteries primarily rely on organic solvents (or organic liquid electrolytes) for their cell structures. Consequently, traditional rechargeable battery technologies have limited potential for improvement in terms of stability and energy density. In contrast, all-solid-state batteries typically employ inorganic solid electrolytes and do not require organic solvents. Therefore, all-solid-state battery technologies have received considerable attention because they offer the ability to manufacture cell structures in a more stable and simpler manner.

[0006] Typically, an all-solid-state battery includes a positive electrode active material layer bonded to the positive current collector, a negative electrode active material layer bonded to the negative current collector, and a solid electrolyte layer interposed between the negative and positive electrode active material layers. However, in addition to the negative electrode active material such as graphite, the negative electrode active material layer also includes a solid electrolyte for transporting lithium ions, and the specific gravity of the solid electrolyte is higher than that of the liquid electrolyte. Therefore, the energy density of existing all-solid-state batteries is lower than that of lithium-ion batteries using liquid electrolytes.

[0007] Recent efforts have focused on increasing the energy density of all-solid-state batteries, particularly those without a negative electrode. These batteries deposit lithium ions directly onto the negative electrode current collector in the form of lithium metal, without a negative electrode active material layer. However, when charged, lithium transported from the positive electrode is deposited onto the negative electrode current collector, forming lithium dendrites. This irreversible increase in capacity (due to the growth of lithium dendrites in the all-solid-state battery) can lead to a decrease in charge / discharge efficiency.

[0008] To address the aforementioned issues, traditionally, sacrificial cathode materials, providing an additional lithium source, are added as additives to the positive electrode active material layer to compensate for irreversible capacity problems. However, when sacrificial cathode materials are added as additives to the positive electrode active material layer, decomposition reactions can create air gaps in the positive electrode, leading to unstable lifetime characteristics. Thus, it remains difficult to add a sufficient amount of sacrificial cathode material to compensate for the irreversible capacity problem. Summary of the Invention

[0009] This disclosure solves the aforementioned problems associated with the prior art while retaining certain advantages already achieved.

[0010] One aspect of this disclosure provides an all-solid-state battery and a method for manufacturing the same, the all-solid-state battery being capable of adding a sacrificial cathode material in an amount sufficient to (i) suppress one or more side reactions caused by the decomposition of the sacrificial cathode material and / or (ii) compensate for the problems.

[0011] The technical problems solved by this disclosure are not limited to those described above. This disclosure can provide solutions to other technical problems not specifically mentioned herein, and those skilled in the art to which this disclosure pertains will clearly understand these technical problems from the following description.

[0012] (1) In one aspect, the present disclosure provides an all-solid-state battery, the all-solid-state battery comprising: a positive current collector; a positive active material layer disposed on the positive current collector and including a positive active material; a solid electrolyte layer disposed on the positive active material layer; a negative electrode disposed on the solid electrolyte layer; and a sacrificial positive electrode layer including a sacrificial active material and disposed between the positive current collector and the positive active material layer.

[0013] (2) In some embodiments, this disclosure provides an all-solid-state battery, wherein, in an exemplary embodiment (1), a sacrificial active material is included in the total weight of the positive active material included in the positive active material layer in an amount ranging from 5 wt% to 20 wt%.

[0014] (3) In some embodiments, this disclosure provides an all-solid-state battery, wherein, in exemplary embodiments (1) or (2), the ionic conductivity of the sacrificial cathode layer ranges from 7.5 × 10⁻⁶. -6 S / cm up to 7.5×10 -4 S / cm.

[0015] (4) In some embodiments, this disclosure provides an all-solid-state battery, wherein, in any of the exemplary embodiments (1) to (3), the electronic conductivity of the sacrificial cathode layer is in the range of 9.6 × 10⁻⁶. -6 S / cm up to 9.6×10 -3 S / cm.

[0016] (5) In some embodiments, this disclosure provides an all-solid-state battery, wherein, in any of the exemplary embodiments (1) to (4), the charging capacity of the sacrificial positive electrode layer ranges from 800 mAh / g to 1200 mAh / g.

[0017] (6) In some embodiments, this disclosure provides an all-solid-state battery, wherein, in any of the exemplary embodiments (1) to (5), the redox potential of the sacrificial active material is lower than the discharge voltage of the positive electrode active material.

[0018] (7) In some embodiments, this disclosure provides an all-solid-state battery, wherein, in any of the exemplary embodiments (1) to (6), the sacrificial positive electrode layer further includes a conductive material, a solid electrolyte and a binder, and includes a sacrificial active material in a content ranging from 50 wt% to 70 wt%, a conductive material in a content ranging from 5 wt% to 15 wt%, a solid electrolyte in a content ranging from 20 wt% to 35 wt%, and a binder in a content ranging from 0.5 wt% to 5 wt%, based on the total weight of the sacrificial positive electrode layer.

[0019] (8) In some embodiments, this disclosure provides an all-solid-state battery, wherein, in any of the exemplary embodiments (1) to (7), the conductive material included in the sacrificial cathode layer is a carbon-based material.

[0020] (9) In some embodiments, this disclosure provides an all-solid-state battery, wherein, in any of the exemplary embodiments (1) to (8), the thickness of the sacrificial cathode layer ranges from 5 μm to 40 μm.

[0021] (10) In some embodiments, this disclosure provides an all-solid-state battery in which the average crystal size of the sacrificial active material, calculated by Formula 1, ranges from 40 nm to 50 nm.

[0022] Formula 1

[0023]

[0024] In Formula 1, Dp is the average crystal size of the sacrificial active material, λ is the wavelength of the X-rays used in the XRD analysis of the sacrificial active material, θ is the Bragg angle of the main peak observed in the XRD analysis of the sacrificial active material, and β is the full width at half maximum (FWMH) of the main peak observed in the XRD analysis of the sacrificial active material.

[0025] (11) In some embodiments, this disclosure provides an all-solid-state battery, wherein, in any of the exemplary embodiments (1) to (10), the solid electrolyte layer comprises a sulfide-based solid electrolyte.

[0026] (12) In some embodiments, this disclosure provides an all-solid-state battery, wherein, in any of the exemplary embodiments (1) to (11), the negative electrode includes: an intermediate layer disposed on a solid electrolyte layer; and a negative current collector disposed on the intermediate layer.

[0027] (13) In some embodiments, this disclosure provides an all-solid-state battery, wherein, in any of the exemplary embodiments (1) to (12), the negative current collector includes at least one selected from the group consisting of nickel (Ni), copper (Cu), stainless steel (SUS), silver (Ag), and combinations of nickel (Ni), copper (Cu), stainless steel (SUS), or silver (Ag).

[0028] (14) In some embodiments, this disclosure provides an all-solid-state battery, wherein, in any of the exemplary embodiments (1) to (13), the intermediate layer includes metal particles for forming an alloy with lithium.

[0029] (15) In another aspect, this disclosure provides a method for manufacturing an all-solid-state battery according to any one or more aspects and embodiments of this disclosure. Attached Figure Description

[0030] The above aspects and embodiments of the present disclosure, as well as other objects, features, and advantages, will become more apparent from the following detailed description taken in conjunction with the accompanying drawings:

[0031] Figure 1 A schematic diagram depicting the overall structure of an all-solid-state battery according to an embodiment of the present disclosure is provided.

[0032] Figure 2 A graph illustrating the resistance (measured by electrochemical impedance spectroscopy) of each half-cell cell manufactured according to the description in Reference Example 1 of this disclosure after the first charge of the half-cell cell is shown.

[0033] Figure 3 A graph illustrating the resistance (measured by electrochemical impedance spectroscopy) of a half-cell cell manufactured according to the description in Reference Example 2 of this disclosure after the first charge of the half-cell cell is shown.

[0034] Figure 4 A graph illustrating the resistance (measured by electrochemical impedance spectroscopy) of a half-cell cell manufactured according to the description in Reference Example 3 of this disclosure after the first charge of the half-cell cell is shown.

[0035] Figure 5 An illustration depicting an image obtained by analyzing the structure of a cross-section of an all-solid-state battery manufactured according to the description in Embodiment 1 of this disclosure via SEM-FIB and EDX.

[0036] Figure 6 A graph depicting the relationship between voltage and areal capacity of all-solid-state batteries manufactured according to Embodiment 1 and Comparative Example 1 of this disclosure.

[0037] Figure 7 The diagram depicts a portion of a graph obtained by magnifying a section of a graph showing the relationship between voltage and specific capacity measured when each of all solid-state batteries according to Embodiment 1, Comparative Example 1, and Comparative Example 2 of this disclosure is discharged.

[0038] Figure 8 A graph depicting the relationship between voltage and specific capacity for each of all solid-state batteries according to Embodiment 1, Comparative Example 1, and Comparative Example 2 of this disclosure; and

[0039] Figure 9 A graph depicting the specific capacity measured per cycle for each of all solid-state batteries manufactured according to Embodiment 1 and the descriptions in Comparative Examples 1 and 2 is presented. Detailed Implementation

[0040] In order to understand this disclosure, it will be described in more detail below.

[0041] Unless otherwise defined in this disclosure, all technical and scientific terms used herein shall be given their common and conventional meanings as commonly understood by one of ordinary skill in the art to which this disclosure pertains. Many terms and abbreviations appear in this disclosure and, unless otherwise defined or indicated, shall be understood to have their reasonably broad common understanding and ordinary meaning consistent with the context in which they are used.

[0042] As used herein, terms such as “first,” “second,” “initial,” and “subsequent” may be used to describe various components, but components are not limited by the terms. These terms are used only to distinguish one component from another. For example, without departing from the scope of this disclosure, a first component may be named a second component, and similarly, a second component may be named a first component.

[0043] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. Singular expressions include plural expressions unless otherwise defined in the context. In this disclosure, it should be understood that the terms “comprising,” “having,” or “including” (or “comprises,” “has,” or “includes”) indicate the presence of the features, numbers, steps, operations, components, parts, or combinations thereof described in this specification, but do not preclude the possibility of the prior presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof. It should be understood that those terms also include the terms “consisting of” or “substantially consisting of,” which, when used throughout the disclosure or claims, generally indicate the presence of the features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and do not include any additional features.

[0044] In a general sense, this disclosure provides an all-solid-state battery that includes one or more features and components that improve upon existing solid-state battery technology.

[0045] According to embodiments of the present disclosure, an all-solid-state battery includes a positive current collector, a positive active material layer disposed on the positive current collector and including a positive active material, a solid electrolyte layer disposed on the positive active material layer, a negative electrode disposed on the solid electrolyte layer, and a sacrificial positive electrode layer including a sacrificial active material and disposed between the positive current collector and the positive active material layer.

[0046] In the following text, reference will be made to Figure 1 The components of an all-solid-state battery according to embodiments of the present disclosure are described in detail. Figure 1 This is a schematic view illustrating the structure of an all-solid-state battery according to an embodiment of the present disclosure.

[0047] positive electrode

[0048] According to embodiments of this disclosure, an all-solid-state battery may include a positive electrode 10.

[0049] According to embodiments of the present disclosure, the positive electrode 10 may include a positive electrode current collector 11, a positive electrode active material layer 13 disposed on the positive electrode current collector 11, and a sacrificial cathode layer 12 disposed between the positive electrode current collector 11 and the positive electrode active material layer 13.

[0050] According to an embodiment of the present disclosure, the positive electrode current collector 11 includes various materials and is not particularly limited as long as the material has conductivity without causing chemical changes in the relevant battery (the all-solid-state battery according to the present disclosure). For example, the positive electrode current collector 11 may include at least one of aluminum (Al), nickel (Ni), titanium (Ti), tungsten (W), iron (Fe), chromium (Cr), and stainless steel, or an alloy thereof. In some embodiments, the positive electrode current collector 11 may be selected from the group consisting of: aluminum (Al), nickel (Ni), titanium (Ti), tungsten (W), iron (Fe), chromium (Cr), stainless steel, and alloys thereof.

[0051] According to an embodiment of the present disclosure, the positive electrode active material layer 13 may include a positive electrode active material, a conductive material, and a binder.

[0052] According to an embodiment of the present disclosure, a positive electrode active material that allows reversible electroplating or release of lithium ions (Li + ) may include a composite oxide of lithium and a metal (i.e., a lithium composite metal oxide). In some specific embodiments, the lithium composite metal oxide may be a lithium-manganese-based oxide (e.g., LiMnO2 or LiMn2O4), a lithium-cobalt-based oxide (e.g., LiCoO2), a lithium-nickel-based oxide (e.g., LiNiO2), a lithium-nickel-manganese-based oxide (e.g., LiNi 1-Y Mn Y O2 (0 < Y < 1), or LiMn 2-z Ni z O4 (0 < Z < 2)), a lithium-nickel-cobalt-based oxide (e.g., LiNi 1-Y1 Co Y1 O2 (0 < Y1 < 1)), a lithium-manganese-cobalt-based oxide (e.g., LiCo 1-Y2 Mn Y2 O2 (0 < Y2 < 1) or LiMn 2-z1 Co z1 O4 (0 < Z1 < 2)), a lithium-nickel-manganese-cobalt-based oxide (e.g., Li(Ni p Co q Mn r1 )O2 (0 < p < 1, 0 < q < 1, 0 < r1 < 1 and p + q + r1 = 1) or Li(Ni p1 Co q1 Mn r2 )O4 (0 < p1 < 2, 0 < q1 < 2, 0 < r2 < 2 and p1 + q1 + r2 = 2)) or a lithium-nickel-cobalt-transition metal (M) oxide (e.g., Li(Ni p2 Co q2 Mn r3 M s2)O2(“M” is selected from the group consisting of Al, Fe, V, Cr, Ti, Ta, Mg, and Mo; p2, q2, r3, and s2 are atomic fractions of independent elements; 0 < p2 < 1, 0 < q2 < 1, 0 < r3 < 1, 0 < s2 < 1, and p2 + q2 + r3 + s2 = 1)), or may contain any one of the above materials or a compound containing at least two of the above materials.

[0053] In some further embodiments, the lithium composite metal oxide can be LiCoO2, LiMnO2, LiNiO2, lithium nickel manganese cobalt oxide (e.g., Li(Ni 1 / 3 Mn 1 / 3 Co 1 / 3 )O2, Li(Ni 0.6 Mn 0.2 Co 0.2 )O2, Li(Ni 0.6 Mn 0.2 Co 0.2 )O2, Li(Ni 0.7 Mn 0.15 Co 0.15 )O2, and Li(Ni 0.8 Mn 0.1 Co 0.1 )O2), or lithium nickel cobalt aluminum oxide (e.g., Li(Ni 0.8 Co 0.15 Al 0.05 )O2), which can enhance the capacity characteristics and stability of the battery. In some specific embodiments that can exhibit one or more improved performance characteristics by controlling the type and content ratio of the components forming the lithium composite metal oxide, the lithium nickel manganese cobalt oxide can be Li(Ni 0.6 Mn 0.2 Co 0.2 )O2, Li(Ni 0.5 Mn 0.3 Co 0.2 )O2, Li(Ni 0.7 Mn 0.15 Co 0.15 )O2, and Li(Ni 0.8 Mn 0.1 Co 0.1 )O2, or any one of the above materials, or a mixture of at least two of the above materials can be employed.

[0054] According to an embodiment of the present disclosure, the positive electrode active material can include boron (B) or LiNbO, and can further include a coating surrounding the lithium composite metal oxide. In embodiments further including a coating, the structural stability of the positive electrode active material can be improved.

[0055] According to another embodiment of this disclosure, the positive electrode active material layer 13 may further include a solid electrolyte. The solid electrolyte can be coated with the positive electrode active material. Therefore, the interfacial compatibility between the positive electrode active material layer 13 and the solid electrolyte layer 20 (described below) can be improved. Throughout this specification, the solid electrolyte according to these embodiments is described with reference to the solid electrolyte layer 20.

[0056] According to embodiments of this disclosure, conductive materials can further improve the conductivity of the positive electrode active material. Conductive materials can include a variety of materials and are not particularly limited, as long as the material is conductive without causing chemical changes in the relevant battery. For example, conductive materials may include graphite; carbon-based materials such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, thermal black, and SC65; conductive fibers such as carbon fibers or metal fibers; metal powders such as fluorinated carbon, aluminum, or nickel powder; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; and / or conductive materials such as polyphenylene derivatives.

[0057] According to embodiments of this disclosure, the adhesive can promote adhesion between the conductive material, the positive electrode active material, and the positive electrode current collector. The adhesive can be polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose, starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene monomer, sulfonated ethylene-propylene-diene monomer, styrene-butadiene rubber, acrylonitrile-butadiene rubber, fluororubber, and / or various copolymers thereof.

[0058] According to embodiments of this disclosure, the all-solid-state battery includes a sacrificial positive electrode layer 12 disposed between the positive current collector 11 and the positive active material layer 13. The sacrificial positive electrode layer 12 (which includes a separate layer containing sacrificial active material) prevents capacity reduction of the all-solid-state battery.

[0059] Typically, all-solid-state batteries can generate side reactions during charging and discharging that consume lithium ions at the interface between the solid electrolyte layer and the negative electrode (in some specific embodiments, the negative electrode current collector). When the lithium ions involved in the side reactions are not compensated (e.g., replaced or replenished), the amount of lithium ions used during charging and discharging is reduced. This, in turn, reduces the capacity of the all-solid-state battery. Typically, a sacrificial active material, acting as an additive, is added to the positive electrode active material layer to compensate for the irreversible consumption of lithium ions. However, in this conventional arrangement, the resulting air gaps, caused by the decomposition of the sacrificial positive electrode material, degrade the structural stability of the positive electrode active material layer. Therefore, using conventional techniques, the sacrificial active material cannot be applied to the positive electrode active material layer in an amount sufficient to compensate for the irreversible consumption of lithium ions (e.g., at least 5 wt% of the total weight of the positive electrode active material layer included in the positive electrode active material layer 13). Conversely, and according to this disclosure, when a sacrificial cathode layer 12 comprising sacrificial active material is situated between the cathode current collector 11 and the cathode active material layer 13, problems related to the air gap can be resolved, reduced, and / or mitigated, and the sacrificial active material can be applied at a level sufficient to compensate for the irreversible consumption of lithium ions. Therefore, the capacity of all solid-state batteries described herein can be improved.

[0060] In an embodiment where the sacrificial cathode layer 12 is located between the cathode active material layer 13 and the solid electrolyte layer 20, the ionic conductivity can be reduced due to the air gap and the decomposition residues generated after the sacrificial active material decomposes, thereby significantly increasing the battery resistance.

[0061] According to embodiments of this disclosure, the sacrificial positive electrode layer 12 may include a sacrificial active material, a conductive material, a binder, and a solid electrolyte.

[0062] According to embodiments of this disclosure, the sacrificial active material included in the sacrificial positive electrode layer 12 has ionic and electronic conductivity. During the initial charging process, the sacrificial active material decomposes into lithium ions and gas, and the decomposed lithium ions can replenish (i.e., resolve, replace, mitigate, or supplement) the irreversible consumption of the aforementioned lithium ions.

[0063] According to embodiments of this disclosure, the sacrificial active material may include a lithium-containing compound having a redox potential lower than that of the positive electrode active material. In some embodiments, the sacrificial active material may include at least one selected from Li3N, Li2O, Li3P, Li2S, Li2CO3, LiNO3, Li2C2O4, and LiAl (an alloy of Li and Al). In some specific embodiments, the sacrificial active material may be Li3P.

[0064] According to embodiments of this disclosure, a sacrificial active material may be included in the sacrificial positive electrode layer 12, with a content ranging from 50 wt% to 70 wt% based on the total weight of the sacrificial positive electrode layer 12. Specifically, the sacrificial active material may be included in a content of at least 51 wt%, at least 52 wt%, at least 53 wt%, at least 54 wt%, or at least 55 wt%, or up to 69 wt%, up to 68 wt%, up to 67 wt%, up to 66 wt%, or up to 65 wt%. In embodiments satisfying the above ranges, the conductivity of the sacrificial active material can be improved.

[0065] According to embodiments of this disclosure, based on the total weight of the sacrificial cathode layer 12, the sacrificial active material can be included in the cathode active material layer 13 in an amount ranging from 5 wt% to 12 wt%. In some specific embodiments, the sacrificial active material can be included in an amount of at least 5.5 wt%, at least 6 wt%, at least 6.5 wt%, at least 7 wt%, or at least 7.5 wt%, or up to 11.5 wt%, up to 11 wt%, up to 10.5 wt%, up to 10 wt%, or up to 9.5 wt%. In embodiments that satisfy the above ranges, an amount of lithium ions sufficient to compensate for lithium ions that might otherwise be irreversibly consumed can be provided.

[0066] According to embodiments of this disclosure, the average crystal size of the sacrificial active material can be in the range of 40 nm to 50 nm. In some specific embodiments, the average crystal size of the sacrificial active material can be at least 41 nm, at least 42 nm, at least 43 nm, or at least 44 nm, or at most 49 nm, at most 48 nm, at most 47 nm, or at most 46 nm. In embodiments that satisfy the above ranges, compensation for irreversible lithium-ion consumption can be performed more easily.

[0067] In some implementations, the average crystal size of the sacrificial active material can be calculated using the following formula 1.

[0068] Formula 1

[0069]

[0070] In Formula 1,

[0071] Dp is the average crystal size of the sacrificial active material.

[0072] λ is the wavelength of X-rays used in the XRD analysis of sacrificial active substances.

[0073] θ is the Bragg angle of the main peak observed in the XRD analysis of the sacrificial active substance, and

[0074] β is the full width at half maximum (FWMH) of the main peak observed in the XRD analysis of the sacrificial active substance. The methods used to determine these figures are known to those skilled in the art, and some of them are described below.

[0075] According to this disclosure, the main peak refers to the peak with the greatest intensity (e.g., highest amplitude, highest value) among the peaks observed in XRD analysis.

[0076] According to embodiments of this disclosure, during the manufacturing process, the average crystal size of the sacrificial active material can be determined by further sintering the mixture of the sacrificial active material and the conductive material at a temperature ranging from 500°C to 700°C.

[0077] According to embodiments of this disclosure, the conductive material included in the sacrificial positive electrode layer 12 can further improve the electrical conductivity of the sacrificial active material. For example, the conductive material may include graphite; carbon-based materials such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, thermal black, and SC65; conductive fibers such as carbon fibers or metal fibers; metal powders such as fluorinated carbon, aluminum, or nickel powder; conductive whiskers such as zinc oxide or potassium titanate; conductive metal oxides such as titanium oxide; and / or conductive materials such as polyphenylene derivatives.

[0078] According to embodiments of this disclosure, based on the total weight of the sacrificial positive electrode layer 12, the conductive material can be included in the sacrificial positive electrode layer 12 in a content ranging from 5 wt% to 15 wt%. In specific embodiments, the conductive material can be included in a content of at least 5.5 wt%, at least 6 wt%, at least 6.5 wt%, at least 7 wt%, or at least 7.5 wt%, or up to 14 wt%, up to 13 wt%, up to 12 wt%, up to 11 wt%, or up to 10 wt%. In embodiments satisfying the above ranges, the conductivity of the sacrificial active material can be improved.

[0079] According to embodiments of this disclosure, the adhesive included in the sacrificial positive electrode layer 12 can promote adhesion between the conductive material, the sacrificial active material, and the solid electrolyte. The adhesive can be polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose, starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene monomer, sulfonated ethylene-propylene-diene monomer, styrene-butadiene rubber, acrylonitrile-butadiene rubber, fluororubber, and various copolymers thereof.

[0080] According to embodiments of this disclosure, the binder may be included in the sacrificial positive electrode layer 12 in a content ranging from 0.5 wt% to 5 wt%, based on the total weight of the sacrificial positive electrode layer 12. In specific embodiments, the binder may be included in a content of at least 0.8 wt%, at least 1 wt%, at least 1.4 wt%, at least 1.8 wt%, or at least 2 wt%, or up to 4.8 wt%, up to 4.6 wt%, up to 4.4 wt%, up to 4.2 wt%, or up to 4 wt%. In embodiments satisfying the above ranges, the bonding between the conductive material, the sacrificial active material, and the solid electrolyte can be performed more easily.

[0081] According to embodiments of this disclosure, the solid electrolyte included in the sacrificial positive electrode layer 12 can improve the ionic conductivity of the sacrificial positive electrode layer 12. Details of the solid electrolyte will be described in the following description discussing the solid electrolyte layer 20.

[0082] According to embodiments of this disclosure, based on the total weight of the sacrificial positive electrode layer 12, the solid electrolyte can be included in the sacrificial positive electrode layer 12 in a content ranging from 20 wt% to 35 wt%. In specific embodiments, the solid electrolyte can be included in a content of at least 21 wt%, at least 22 wt%, at least 23 wt%, at least 24 wt%, or at least 25 wt%, or at most 34 wt%, at most 33 wt%, at most 32 wt%, at most 31 wt%, or at most 30 wt%. In embodiments satisfying the above ranges, the ionic conductivity of the sacrificial positive electrode layer 12 can be further improved.

[0083] According to embodiments of this disclosure, the thickness of the sacrificial cathode layer 12 can range from 15 μm to 25 μm. Specifically, the thickness of the sacrificial cathode layer 12 can be at least 15.5 μm, at least 16 μm, at least 16.5 μm, at least 17 μm, or at least 17.5 μm, or can be at most 24.5 μm, at most 24 μm, at most 23.5 μm, at most 23 μm, or 22.5 μm. In embodiments satisfying the above ranges, a sufficient amount of lithium ions can be provided to compensate for the irreversible consumption of lithium ions.

[0084] According to embodiments of this disclosure, the ionic conductivity of the sacrificial cathode layer 12 can be in the range of 7.5 × 10⁻⁶. -6 S / cm up to 7.5×10 -4 S / cm. Specifically, the ionic conductivity of the sacrificial cathode layer 12 can be at least 8.0 × 10⁻⁶. -6 S / cm, at least 8.5×10 -6 S / cm, at least 9.0 × 10 -6 S / cm, at least 9.5×10 -6 S / cm, or at least 1.0 × 10 -5S / cm, or up to 7.0×10 -4 S / cm, maximum 6.5×10 -4 S / cm, maximum 6.0×10 -4 S / cm, maximum 5.5×10 -4 S / cm, or up to 5.0 × 10 -4 S / cm. In embodiments that meet the above range, the sacrificial active material contained in the sacrificial positive electrode layer 12 can be effectively decomposed, thereby easily retaining lithium ions.

[0085] According to embodiments of this disclosure, the electronic conductivity of the sacrificial positive electrode layer 12 can be in the range of 9.6 × 10⁻⁶. -6 S / cm up to 9.6×10 -3 S / cm. In a specific embodiment, the electronic conductivity of the sacrificial positive electrode layer 12 can be at least 9.8 × 10⁻⁶. -6 S / cm, at least 1.0 × 10 -5 S / cm, at least 1.5×10 -5 S / cm, at least 2.0 × 10 -5 S / cm, at least 4.0 × 10 -5 S / cm, or up to 9.0 × 10 -3 S / cm, maximum 8.0×10 -3 S / cm, maximum 6.0×10 -3 S / cm, maximum 4.0×10 -3 S / cm, or at most 1.0×10 -4 S / cm. In embodiments that satisfy the above range, the sacrificial cathode layer 12 can effectively transfer electrons to the cathode active material layer 13.

[0086] According to embodiments of this disclosure, the charging capacity of the sacrificial cathode layer 12 can be in the range of 800 mAh / g to 1200 mAh / g. In specific embodiments, the charging capacity of the sacrificial cathode layer 12 can be at least 820 mAh / g, at least 840 mAh / g, at least 860 mAh / g, at least 880 mAh / g, or at least 900 mAh / g, or at most 1180 mAh / g, at most 1160 mAh / g, at most 1140 mAh / g, at most 1120 mAh / g, or at most 1100 mAh / g. In embodiments satisfying the above ranges, the energy density of the all-solid-state battery can be effectively improved.

[0087] solid electrolyte layer

[0088] According to embodiments of this disclosure, an all-solid-state battery may include a solid electrolyte layer 20. The solid electrolyte layer 20 may be inserted between a positive electrode 10 and a negative electrode 30 to transfer lithium ions present between the positive electrode 10 and the negative electrode 30.

[0089] According to embodiments of this disclosure, the solid electrolyte layer 20 may be disposed on the positive electrode active material layer 13, and may include a solid electrolyte having lithium-ion conductivity. The solid electrolyte includes at least one or a combination of oxide-based solid electrolytes, sulfide-based solid electrolytes, and polymer electrolytes, and in some preferred embodiments, may include a sulfide-based solid electrolyte.

[0090] According to embodiments of this disclosure, sulfide-based solid electrolytes may include Li6PS5X (X = at least one of Cl, Br, and I), Li 10 GeP2S 12 Li3PS4, Li7P3S 11 , Li2S-P2S5, Li2S-P2S5-LiI, Li2S-P2S5-LiCl, Li2S-P2S5-LiBr, Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-SiS2, L i2SSiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z m S n (Where "m" and "n" are positive numbers; Z is one of Ge, Zn, and Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li x MO y (where “x” and “y” are positive numbers; M is one of P, Si, Ge, B, Al, Ga and In) and / or combinations thereof.

[0091] negative electrode

[0092] According to embodiments of this disclosure, an all-solid-state battery may include a negative electrode 30. The negative electrode 30 may be disposed on a solid electrolyte layer 20 and may include a negative electrode current collector 31 and an intermediate layer 32.

[0093] According to embodiments of the present disclosure, the intermediate layer 32 may be disposed on the solid electrolyte layer 20, and the negative electrode current collector 31 may be disposed on the intermediate layer 32.

[0094] According to embodiments of this disclosure, the negative electrode current collector 31, used as a conductive plate-shaped substrate, may comprise a material that does not react with lithium. In some specific embodiments, the negative electrode current collector 31 comprises various materials and is not particularly limited, as long as these materials are conductive without causing chemical changes in the relevant battery. In some specific embodiments, the negative electrode current collector 10 may be at least one of aluminum (Al), nickel (Ni), titanium (Ti), tungsten (W), iron (Fe), chromium (Cr), and / or stainless steel, or alloys thereof.

[0095] According to embodiments of the present disclosure, when lithium ions are deposited on the surface of the negative electrode current collector 10 in the form of lithium metal, the intermediate layer 32, which is a component coated on the negative electrode current collector 31, can easily react with lithium ions to form an alloy and cause the deposition of lithium metal oriented in a horizontal direction along the surface of the negative electrode current collector 31.

[0096] According to embodiments of this disclosure, the intermediate layer 32 may include a metal for forming an alloy with lithium. In some specific embodiments, the intermediate layer 32 may include beryllium (Be), magnesium (Mg), aluminum (Al), silicon (Si), calcium (Ca), scandium (Sc), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), gallium (Ga), germanium (Ge), arsenic (As), strontium (Sr), yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), technetium (Tc), rhodium (Rh), palladium (Pd), silver (Ag), cadmium (Cd), indium (In), tin (Sn), antimony (Sb), tellurium (Te), barium (Ba), hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), iridium (Ir), platinum (Pt), gold (Au), mercury (Hg), thallium (TI), phosphorus (Pb), or bismuth (Bi), and / or combinations thereof.

[0097] According to embodiments of this disclosure, the thickness of the intermediate layer 32 can range from 100 nm to 1000 nm. In embodiments that satisfy the above range, the interface between the intermediate layer 32 and the solid electrolyte layer 20 can be uniformly formed, and lithium metal can be easily deposited in the horizontal direction along the surface of the negative electrode current collector 31.

[0098] According to embodiments of the present disclosure, the intermediate layer 32 can be formed on the negative electrode current collector 31 by performing a sputtering process on a metal used to form an alloy with lithium.

[0099] According to embodiments of the present disclosure, the intermediate layer 32 may include a negative electrode active material layer containing a negative electrode active material.

[0100] According to another embodiment of this disclosure, the negative electrode active material is not particularly limited, and may include, for example, carbon active materials and metal active materials.

[0101] According to another embodiment of this disclosure, the carbon-active material may be graphite, such as mesophase carbon microspheres (MCMB) and highly oriented graphite (HOPG), or amorphous carbon, such as hard carbon and soft carbon.

[0102] According to another embodiment of this disclosure, the metal active material may be In, Al, Si, Sn, Ag, Zn, or an alloy containing at least one of In, Al, Si, Sn, Ag, or Zn.

[0103] Exemplary embodiments of this disclosure will be described in detail below so that those skilled in the art can readily understand and reproduce embodiments according to this disclosure. However, it should be understood that this disclosure may be implemented in various forms and is not limited to the embodiments described herein.

[0104] Example 1

[0105] 1) Formation of the solid electrolyte layer

[0106] Including Li6PS5Cl 0.5 Br 0.5 90 mg of solid electrolyte powder was placed in a mold with an inner diameter of 10 mm and compressed at 200 MPa to form a solid electrolyte layer.

[0107] 2) Formation of the positive electrode active material layer

[0108] 20 mg of positive electrode active material (LiNi) will be mixed with each other in a ratio of 70:30:3. 0.8 Co 0.1 Mn 0.1 O2), solid electrolyte (Li6PS5Cl) 0.5 Br 0.5 Powder of 1) and binder (VGCF) is placed in a mold and compressed at 200 MPa, thereby forming a positive electrode active material layer on one surface of the solid electrolyte layer formed in 1).

[0109] 3) Formation of the sacrificial cathode layer

[0110] 0.1 g of red phosphorus (“Red P”) (Sigma Aldrich) as a phosphorus precursor and 0.025 g of SC65 (TIMCAL) as a conductive material were introduced into a reactor and subjected to high-energy ball milling (HEBM) at 300 RPM for 20 hours to prepare red P-SC65 composite powder. 1.61 g of lithium biphenyl (Sigma Aldrich) dissolved in THF solution was added to the prepared red P-SC65 composite powder to prepare Li3P-SC65 composite powder. The prepared Li3P-SC65 composite powder was calcined at 600 °C for 4 hours to prepare crystalline Li3P-SC65 composite powder. Subsequently, 1.68 mg of crystalline Li3P-SC65 composite powder and 0.67 mg of solid electrolyte (Li6PS5Cl) were added. 0.5 Br 0.5 The powder and 0.04 mg of binder (NBR) powder were matched to one surface of the positive electrode active material layer formed in step 2) and compressed at 380 MPa to form a sacrificial positive electrode layer.

[0111] 4) Manufacturing of the negative electrode

[0112] After preparing a 10 μm thick positive current collector comprising SUS316, a silver (Ag) thin film was formed on the surface of the positive current collector by DC sputtering to fabricate the positive electrode. During positive electrode fabrication, sputtering powers of 10 W, 20 W, 30 W, and 50 W were applied. The fabricated positive electrode was surface-matched to the solid electrolyte layer formed in step 1) and compressed at 380 MPa.

[0113] 5) Manufacturing of the positive current collector

[0114] After preparing a positive current collector with a thickness of 10 μm and including Al, the positive current collector is matched with a surface of the sacrificial positive electrode layer formed in 3), and compressed at 380 MPa to form a positive current collector, thereby manufacturing an all-solid-state battery.

[0115] Comparative Example 1

[0116] The all-solid-state battery is manufactured in the same manner as in Example 1, except that the sacrificial cathode layer is omitted.

[0117] Comparative Example 2

[0118] 1) Formation of the solid electrolyte layer

[0119] Including Li6PS5Cl 0.5 Br 0.5 90 mg of solid electrolyte powder was placed in a mold with an inner diameter of 10 mm and compressed at 200 MPa to form a solid electrolyte layer.

[0120] 2) Formation of the negative electrode active material layer

[0121] 21.4 mg of positive electrode active material (LiNi) will be mixed with each other in a ratio of 70:30:3:7. 0.8 Co 0.1 Mn 0.1 O2), solid electrolyte (Li6PS5Cl) 0.5 Br 0.5 Powders of binder (VGCF) and sacrificial active material (Li3P) are placed in a mold and compressed at 200 MPa, thereby forming a positive electrode active material layer on one surface of the solid electrolyte layer formed in step 1).

[0122] 3) Manufacturing of the negative electrode

[0123] After preparing a 10 μm thick positive current collector comprising SUS316, a silver (Ag) thin film was formed on the surface of the negative current collector by DC sputtering to fabricate the negative electrode. During negative electrode fabrication, sputtering powers of 10 W, 20 W, 30 W, and 50 W were applied. The fabricated negative electrode was surface-matched to the solid electrolyte layer formed in step 1) and compressed at 380 MPa.

[0124] 4) Manufacturing of the positive current collector

[0125] After preparing a positive current collector with a thickness of 10 μm and including Al, the positive current collector is matched with a surface of the positive active material layer formed in 2), and compressed at 380 MPa to form a positive current collector, thereby manufacturing an all-solid-state battery.

[0126] Reference Example 1

[0127] 1) Formation of the solid electrolyte layer

[0128] Including Li6PS5Cl 0.5 Br 0.5 90 mg of solid electrolyte powder was placed in a mold with an inner diameter of 10 mm and compressed at 200 MPa to form a solid electrolyte layer.

[0129] 2) Formation of the positive electrode active material layer

[0130] 20 mg of positive electrode active material (LiNi) will be mixed with each other in a ratio of 70:30:3. 0.8 Co 0.1 Mn 0.1 O2), solid electrolyte (Li6PS5Cl) 0.5 Br 0.5Powders of 1) and binder (VGCF) are placed in a mold and compressed at 200 MPa to form a positive electrode active material layer on one surface of the solid electrolyte layer formed as 1).

[0131] 3) Manufacturing of the negative electrode

[0132] The Li metal foil stamped at 9pi is matched with the relative surface of the solid electrolyte layer formed in 1), and compressed at 380MPa.

[0133] See Example 2

[0134] 1) Formation of the solid electrolyte layer

[0135] Including Li6PS5Cl 0.5 Br 0.5 90 mg of solid electrolyte powder was placed in a mold with an inner diameter of 10 mm and compressed at 200 MPa to form a solid electrolyte layer.

[0136] 2) Formation of the positive electrode active material layer

[0137] 20 mg of positive electrode active material (LiNi) will be mixed with each other in a ratio of 70:30:3. 0.8 Co 0.1 Mn 0.1 O2), solid electrolyte (Li6PS5Cl) 0.5 Br 0.5 Powders of 1) and binder (VGCF) are placed in a mold and compressed at 200 MPa to form a positive electrode active material layer on one surface of the solid electrolyte layer formed as 1).

[0138] 3) Formation of the sacrificial cathode layer

[0139] 0.1 g of red P (Sigma Aldrich) as a phosphorus precursor and 0.025 g of SC65 (TIMCAL) as a conductive material were introduced into a reactor, and the mixture was subjected to high-energy ball milling (HEBM) at 300 RPM for 20 hours to prepare red P-SC65 composite powder. 1.61 g of lithium biphenyl (Sigma Aldrich) dissolved in THF solution was added to the prepared red P-SC65 composite powder to prepare Li3P-SC65 composite powder. The prepared Li3P-SC65 composite powder was calcined at 600 °C for 4 hours to prepare crystalline Li3P-SC65 composite powder. Subsequently, 1.68 mg of crystalline Li3P-SC65 composite powder and 0.67 mg of solid electrolyte (Li6PS5Cl) were added... 0.5 Br 0.5The powder and 0.04 mg of binder (NBR) powder were matched to one surface of the positive electrode active material layer formed in step 2) and compressed at 380 MPa to form a sacrificial positive electrode layer.

[0140] 4) Manufacturing of the negative electrode

[0141] The Li metal foil stamped at 9pi is matched with the relative surface of the solid electrolyte layer formed in 1), and compressed at 380MPa.

[0142] See Example 3

[0143] 1) Formation of the solid electrolyte layer

[0144] Including Li6PS5Cl 0.5 Br 0.5 90 mg of solid electrolyte powder was placed in a mold with an inner diameter of 10 mm and compressed at 200 MPa to form a solid electrolyte layer.

[0145] 2) Formation of the sacrificial cathode layer

[0146] 0.1 g of red P (Sigma Aldrich) as a phosphorus precursor and 0.025 g of SC65 (TIMCAL) as a conductive material were introduced into a reactor, and the mixture was subjected to high-energy ball milling (HEBM) at 300 RPM for 20 hours to prepare red P-SC65 composite powder. 1.61 g of lithium biphenyl (Sigma Aldrich) dissolved in THF solution was added to the prepared red P-SC65 composite powder to prepare Li3P-SC65 composite powder. The prepared Li3P-SC65 composite powder was calcined at 600 °C for 4 hours to prepare crystalline Li3P-SC65 composite powder. Subsequently, 1.68 mg of crystalline Li3P-SC65 composite powder and 0.67 mg of solid electrolyte (Li6PS5Cl) were added... 0.5 Br 0.5 Powder and 0.04 mg binder (NBR) powder are matched with one surface of the solid electrolyte layer formed in step 2 and pressed at 380 MPa to form a sacrificial positive electrode layer.

[0147] 3) Manufacturing of the negative electrode

[0148] The Li metal foil stamped at 9pi is matched with the relative surface of the solid electrolyte layer formed in 1), and compressed at 380MPa.

[0149] Experimental Example 1: Evaluation of degradation through sacrificial cathode layer

[0150] Following the initial charging process, the resistance of the half-cell units obtained in each of Reference Examples 1 to 3 was measured by electrochemical impedance spectroscopy (EIS), and the results are shown in Table 1 and... Figures 2 to 4 middle.

[0151] Table 1

[0152] Reference Example 1 See Example 2 See Example 3 <![CDATA[R 1 =10Ω]]> <![CDATA[R 2 =50Ω]]> <![CDATA[R 3 =39.5Ω]]>

[0153] In Table 1, R 1 R refers to the resistance excluding the resistance of the solid electrolyte in a half-cell unit (negative electrode / solid electrolyte layer / positive electrode active material layer) that does not have a sacrificial positive electrode layer. 2 This refers to the resistance of a half-cell unit with a sacrificial positive electrode layer (negative electrode / solid electrolyte layer / positive active material layer / sacrificial positive electrode layer), and R 3 This refers to the resistance of a half-cell unit (negative electrode / solid electrolyte layer / sacrificial positive electrode layer) that only has a sacrificial positive electrode layer. In this case, R 1 To R 3 It can be represented as follows.

[0154] R 1 =R Li / SE +R sE / NCM +R NCM(内部)

[0155] R 2 =R Li / SE +R SE +R SE / NCM +R NCM(内部) +R NCM / Li3P +R Li3P c (内部)

[0156] R 3 =R Li / SE +R SE +R SE / Li3P +R Li3P(内部)

[0157] In the above formula, R Li / sE R refers to the interfacial resistance between the positive electrode (Li) and the solid electrolyte layer (SE). SE / NCM R refers to the interfacial resistance between the solid electrolyte layer (SE) and the positive electrode active material layer (NCM). NCM(内部) R refers to the internal resistance of the positive electrode active material layer (NCM). SE R refers to the internal resistance of the solid electrolyte layer (SE). NCM / Li3P It refers to the interfacial resistance between the positive electrode active material layer (NCM) and the sacrificial positive electrode layer (Li3P), and R Li3P(内部) This refers to the internal resistance of the sacrificial positive electrode layer (Li3P), and RSE / Li3P It refers to the interfacial resistance between the solid electrolyte layer (SE) and the sacrificial cathode layer (Li3P).

[0158] In such an implementation, regarding R NCM / Li3P The resistance between the positive active material forming the positive electrode active material layer and the sacrificial active material forming the sacrificial positive electrode layer is determined to be the dominant resistance, and the positive and sacrificial active materials are mixed with the solid electrolyte. Therefore, R NCM / Li3P This can be determined as the resistance between the solid electrolyte and the solid electrolyte. Furthermore, regarding R... SE / Li3P The resistance between the solid electrolyte forming the solid electrolyte layer and the sacrificial active material forming the sacrificial positive electrode layer is determined to be the main resistance, and the sacrificial active material is mixed with the solid electrolyte as described above. Therefore, R SE / Li3P This can be defined as the resistance between two solid electrolytes. Therefore, R, as the resistance between two solid electrolytes... NCM / Li3P and R SE / Li3P They are basically similar to each other. Therefore, assume R NCM / Li3P Equal to R SE / Li3P R 2 -R 3 =R SE / NCM +R NCM(内部) = 10.5Ω. In this formula, the calculated values ​​indicate the positive electrode interface resistance and internal resistance when a sacrificial positive electrode layer is applied.

[0159] In some implementations, R 1 =R Li / SE +R SE / NCM +R NCM(内部) =10Ω. In this case, when the battery operates at 30MPa, the negative electrode and the solid electrolyte layer are firmly bonded to each other, so the interfacial resistance between the negative electrode and the solid electrolyte layer is negligible. Therefore, In this formula, the calculated values ​​indicate the positive electrode interface resistance and internal resistance when no sacrificial positive electrode layer is applied.

[0160] In such implementations, when a sacrificial cathode layer is applied, R SE / NCM +R NCM(内部) =10.5Ω, and when no sacrificial cathode layer is applied, R SE / NCM +R NCM(内部) =10Ω. Therefore, both cases can be determined to exhibit similar resistance. Therefore, it can be determined that after the charging process, the sacrificial positive electrode layer will not cause meaningful degradation at the positive electrode interface of the all-solid-state battery or inside the all-solid-state battery.

[0161] Experimental Example 2: Measurement of the physical properties of the sacrificial cathode layer

[0162] <Observations on the Structure of the Sacrificial Positive Electrode Layer>

[0163] To analyze the cross-section of the all-solid-state battery fabricated in Example 1, the cross-section was pre-processed using a Helios Nanolab 450hp dual-beam scanning electron microscope with focused ion beam (SEM-FIB), and then observed by TEM. Figure 5 The results are shown in the figure. Furthermore, to analyze the cross-section using energy-dispersive X-ray spectroscopy (EDX), the distributions of P and S elements were observed, and... Figure 5 The observations are shown in the figure.

[0164] refer to Figure 5 The presence of Li3P included in the sacrificial cathode layer can be identified by the P-mapping image measured via EDX. Therefore, it can be recognized that the thickness of the sacrificial cathode layer measured in Example 1 is 20 μm. Furthermore, it can be recognized that a solid electrolyte is mixed in the sacrificial cathode layer by the S-mapping image measured via EDX.

[0165] <Measurement of the sacrificial positive electrode layer for charging capacity>

[0166] Figure 6 The graph shows the relationship between voltage and areal capacity when all solid-state batteries manufactured in Example 1 and Comparative Example 1 are pre-charged to 4.3V at a current density of 0.1 mA / cm² under conditions of 30°C and 30 MPa.

[0167] refer to Figure 6 It can be recognized that, compared with Comparative Example 1 without a sacrificial cathode layer, the areal capacity increased by 2.5 mAh / cm² in the example including the sacrificial cathode layer. 2 Furthermore, as in Figure 5 As observed, it can be recognized that, since the thickness of the sacrificial cathode layer according to Example 1 is 20 μm, an additional 1.25 mAh / cm² is achieved for every 10 μm of sacrificial cathode layer. 2 Area capacity.

[0168] Experimental Example 3: Calculation of Average Crystal Size (XRD Analysis)

[0169] X-ray diffraction (XRD) was performed on the crystalline Li3P-SC65 composite powder used in Example 1, and the average crystal size of Li3P (the sacrificial active material) was calculated using the following Formula 1.

[0170] Formula 1

[0171]

[0172] In Formula 1,

[0173] Dp is the average crystal size of the sacrificial active material.

[0174] λ is the wavelength of X-rays used in the XRD analysis of sacrificial active substances.

[0175] θ is the Bragg angle of the main peak observed in the XRD analysis of the sacrificial active substance, and

[0176] β is the full width at half maximum (FWMH) of the main peak observed in the XRD analysis of the sacrificial active substance.

[0177] The average crystal size of Li3P (sacrificial active material) according to Example 1, calculated using Formula 1, is 44.62 nm.

[0178] Experiment Example 4: Measurement of Battery Characteristics

[0179] Figure 7 and Figure 8 The graph shows the relationship between voltage and areal capacity when all solid-state batteries manufactured in Example 1 and Comparative Examples 1 and 2 are charged to 4.3V at a current density of 0.5mA / cm2 and discharged to 3V at a current density of 0.5mA / cm2 under conditions of 30°C and 30MPa.

[0180] Furthermore, assuming a cycle is defined as the time period during which all solid-state batteries manufactured in Example 1, Comparative Example 1, and Comparative Example 2 are charged to 4.3V at a current density of 0.5mA / cm² and discharged to 3V at a current density of 0.5mA / cm², and the charge and discharge operations are repeated up to the 100th cycle under conditions of 30°C and 30MPa, and a graph representing the specific capacity measured for each cycle is shown. Figure 9 As shown in the image.

[0181] Figure 7 This view is obtained by magnifying a portion of a graph showing the relationship between voltage and specific capacity measured when each of the solid-state batteries in Example 1 and Comparative Examples 1 and 2 of this disclosure is discharged. Reference Figure 7Compared to Comparative Example 1, which does not have a sacrificial cathode material, a positive electrode discharge overpotential of 38 mV was identified in Example 1, which uses a sacrificial cathode material as a single layer. Furthermore, compared to Comparative Example 1, which does not have a sacrificial cathode material, a positive electrode discharge overpotential of 94 mV was identified in Comparative Example 2, which uses a sacrificial cathode material as an additive in the positive electrode active material layer. Therefore, it can be recognized that the increase in positive electrode discharge overpotential was suppressed in the all-solid-state battery according to Example 1 compared to the all-solid-state battery according to Comparative Example 2. This is likely because less gas gap and resistance are formed due to the decomposition reaction of the sacrificial active material, since the sacrificial cathode material is applied as a single layer in the all-solid-state battery according to Example 1.

[0182] Figure 8 This is a graph showing the relationship between voltage and specific capacity for each of the solid-state batteries in Example 1, Comparative Example 1, and Comparative Example 2 of this disclosure. (See also...) Figure 8 It can be recognized that, compared to Comparative Example 1, the initial discharge capacity in Example 1 was improved by 61 mAh / g, and compared to Comparative Example 1, the initial discharge capacity in Comparative Example 2 was improved by 15 mAh / g. Therefore, it can be recognized that the initial discharge capacity increases when the sacrificial cathode material exists as a single layer, relative to when the sacrificial cathode material is introduced into the cathode active material layer.

[0183] Figure 9 This is a graph showing the specific capacity measured per cycle for each of all solid-state batteries manufactured in Example 1 and Comparative Examples 1 and 2. (See reference...) Figure 9 Based on the 100th cycle, it can be recognized that all solid-state batteries according to Example 1 exhibit the best discharge capacity. Meanwhile, for Comparative Example 2, the experiment could not proceed to the 100th cycle because air gaps were formed in the negative electrode active material layer due to the decomposition of the sacrificial active material.

[0184] According to examples of this disclosure, an all-solid-state battery includes an insulating layer comprising a sacrificial cathode material, rather than the sacrificial cathode material being included in the cathode active material layer as an additive. Therefore, side reactions resulting from the decomposition of the sacrificial cathode material can be suppressed, and the sacrificial cathode material can be added in an amount sufficient to compensate for this irreversibility problem.

[0185] According to examples of this disclosure, in a method for manufacturing an all-solid-state battery, the all-solid-state battery can be manufactured to suppress side reactions caused by the decomposition of the sacrificial cathode material, and an amount of sacrificial cathode material sufficient to compensate for irreversible problems can be added.

[0186] While this disclosure has been described above with reference to exemplary examples and accompanying drawings, it is not limited thereto, but can be modified and altered by those skilled in the art without departing from the spirit and scope of the disclosure as claimed in the appended claims.

Claims

1. An all-solid-state battery, comprising: Positive current collector; A positive electrode active material layer is disposed on the positive electrode current collector and includes a positive electrode active material; A solid electrolyte layer is disposed on the positive electrode active material layer; The negative electrode is disposed on the solid electrolyte layer; and A sacrificial positive electrode layer includes a sacrificial active material and is disposed between the positive electrode current collector and the positive electrode active material layer.

2. The all-solid-state battery according to claim 1, wherein, The sacrificial active material is included in an amount ranging from 5 wt% to 20 wt% based on the total weight of the positive active material included in the positive active material layer.

3. The all-solid-state battery according to claim 1, wherein, The ionic conductivity of the sacrificial cathode layer is in the range of 7.5 × 10⁻⁶. -6 S / cm up to 7.5×10 -4 S / cm.

4. The all-solid-state battery according to claim 1, wherein, The electronic conductivity of the sacrificial positive electrode layer is in the range of 9.6 × 10⁻⁶. -6 S / cm up to 9.6×10 -3 S / cm.

5. The all-solid-state battery according to claim 1, wherein, The charging capacity of the sacrificial cathode layer ranges from 800 mAh / g to 1200 mAh / g.

6. The all-solid-state battery according to claim 1, wherein, The redox potential of the sacrificial active material is lower than the discharge voltage of the positive electrode active material.

7. The all-solid-state battery according to claim 1, wherein, The sacrificial positive electrode layer also includes conductive materials, a solid electrolyte, and a binder, and Wherein, based on the total weight of the sacrificial positive electrode layer The sacrificial active substance is included in an amount ranging from 50 wt% to 70 wt%. The conductive material is included in an amount ranging from 5 wt% to 15 wt%. The solid electrolyte is included in an amount ranging from 20 wt% to 35 wt%, and the binder is included in an amount ranging from 0.5 wt% to 5 wt%.

8. The all-solid-state battery according to claim 7, wherein, The conductive material included in the sacrificial cathode layer is a carbon-based material.

9. The all-solid-state battery according to claim 1, wherein, The thickness of the sacrificial cathode layer ranges from 5 μm to 40 μm.

10. The all-solid-state battery according to claim 1, wherein, The average crystal size of the sacrificial active material, calculated using the following formula 1, ranges from 40 nm to 50 nm. Formula 1 Wherein, in Formula 1, Dp is the average crystal size of the sacrificial active material. λ is the wavelength of the X-rays used in the XRD analysis of the sacrificial active material, θ is the Bragg angle of the main peak observed in the XRD analysis of the sacrificial active material, and β is the full width at half maximum (FWHM) of the main peak observed in the XRD analysis of the sacrificial active substance.

11. The all-solid-state battery according to claim 1, wherein, The solid electrolyte layer includes a sulfide-based solid electrolyte.

12. The all-solid-state battery according to claim 1, wherein, The negative electrode includes: An intermediate layer is disposed on the solid electrolyte layer; and The negative current collector is disposed on the intermediate layer.

13. The all-solid-state battery according to claim 12, wherein, The negative current collector includes at least one of nickel, copper, stainless steel, silver, and combinations of nickel, copper, stainless steel, or silver.

14. The all-solid-state battery according to claim 13, wherein, The intermediate layer includes metal particles for forming an alloy with lithium.

15. The all-solid-state battery according to claim 14, wherein, The metal particles include one or more of the following: beryllium, magnesium, aluminum, silicon, calcium, scandium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, germanium, arsenic, strontium, yttrium, zirconium, niobium, molybdenum, technetium, rhodium, palladium, silver, cadmium, indium, tin, antimony, tellurium, barium, hafnium, tantalum, tungsten, rhenium, iridium, platinum, gold, mercury, thallium, phosphorus or bismuth, and / or combinations thereof.

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