Anode-free all-solid-state battery

Abstract

An anode-free all-solid-state battery includes: an anode current collector; a first intermediate layer disposed on the anode current collector and including a first metal for forming a solid solution alloy with lithium; a second intermediate layer disposed on the first intermediate layer and including a second metal for forming an intermetallic alloy with lithium; a solid electrolyte layer disposed on the second intermediate layer; a cathode active material layer disposed on the solid electrolyte layer; and a cathode current collector disposed on the cathode active material layer.

Description

[0001] Citations of relevant applications

[0002] This application claims the benefit and priority of Korean Patent Application No. 10-2024-0189164, filed with the Korean Intellectual Property Office on December 17, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure provides an anodeless all-solid-state battery that includes an intermediate layer of deposited lithium. Background Technology

[0004] Rechargeable batteries are already used not only in smaller electronic devices, such as mobile phones or laptops, but also in larger transportation vehicles, such as hybrid or electric vehicles. Therefore, there is a need to develop rechargeable batteries with high stability and energy density.

[0005] For conventional secondary batteries, cells are primarily formed using organic solvents (or organic liquid electrolytes). Therefore, traditional secondary batteries have limitations in improving stability and energy density. All-solid-state batteries, employing inorganic solid electrolytes, are based on technologies that do not use organic solvents. Consequently, all-solid-state batteries have recently attracted significant attention due to their ability to manufacture cells in a more stable and simpler form.

[0006] All-solid-state batteries comprise a cathode active material layer bonded to a cathode current collector, an anode active material layer bonded to an anode current collector, and a solid electrolyte layer situated between the cathode and anode active material layers. However, in addition to the anode active material such as graphite, the anode active material layer also includes a solid electrolyte for transporting lithium ions, and this solid electrolyte has a higher specific gravity than liquid electrolytes. Therefore, the energy density of all-solid-state batteries is lower than that of lithium-ion batteries using liquid electrolytes.

[0007] To increase the energy density of all-solid-state batteries, anode-less all-solid-state batteries of storage type have been explored and studied to directly deposit lithium ions in the form of lithium metal on the anode current collector without an anode active material layer. However, when the anode-less all-solid-state battery is charged, lithium transported from the cathode is plated onto the anode current collector, forming lithium dendrites. Summary of the Invention

[0008] This disclosure has been made to address the aforementioned problems in the prior art while retaining the advantages achieved by the prior art.

[0009] One aspect of this disclosure provides an anode-free all-solid-state battery capable of preventing internal short circuits because a lithium-plated layer is additionally formed between the solid electrolyte layer and the intermediate layer. Even during higher charge / discharge rates, the anode-free all-solid-state battery is able to charge more stably.

[0010] The technical problems to be solved by this disclosure are not limited to those described above, and any other technical problems not mentioned herein should be clearly understood by those skilled in the art from the following description.

[0011] One aspect of this disclosure provides an anode-free all-solid-state battery, comprising: an anode current collector; a first intermediate layer disposed on the anode current collector and comprising a first metal for forming a solid solution alloy with lithium; a second intermediate layer disposed on the first intermediate layer and comprising a second metal for forming an intermetallic alloy with lithium; a solid electrolyte layer disposed on the second intermediate layer; a cathode active material layer disposed on the solid electrolyte layer; and a cathode current collector disposed on the cathode active material layer. Attached Figure Description

[0012] The above and other aspects, features and advantages of this disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings.

[0013] Figure 1 This is a schematic diagram illustrating the charging state of an anode-free all-solid-state battery according to an embodiment of the present disclosure.

[0014] Figure 2 SEM images and EDS spectra of cross sections of lithium-plated anode-free all-solid-state batteries according to Example 1 and Comparative Example 1 of this disclosure are shown.

[0015] Figure 3 This is a graph showing the behavior of lithium plating measured in an anode-free all-solid-state battery according to Reference Example 1 and Reference Example 2.

[0016] Figure 4 This is a graph showing the behavior of lithium plating measured in the anode-free all-solid-state batteries according to Example 1 and Comparative Example 1;

[0017] Figure 5 It is a graph showing the voltage-to-capacity ratio measured during the charging / discharging process according to Example 1 and Comparative Example 1.

[0018] Figure 6 It is a graph showing the specific capacity for each cycle according to Example 1 and Comparative Example 1. Detailed Implementation

[0019] To facilitate understanding of this disclosure, it is described in more detail below. In this context, the terms or words used in this specification and claims should not be construed as having their common dictionary meaning, but rather as being interpreted based on the inventor's ability to appropriately define the concepts of the terms, and are to be understood in relation to the technical scope of this disclosure.

[0020] The terminology used in this disclosure is provided for illustrative purposes only, and this disclosure is not limited thereto. Unless the context clearly indicates otherwise, the singular form is intended to include the plural form.

[0021] In this specification, it should be further understood that the terms “comprise,” “include,” or “has” specify the presence of the stated features, quantities, steps, components, parts, or combinations thereof, but do not exclude the presence or addition of one or more other features, quantities, steps, components, and / or combinations thereof.

[0022] When components, controllers, devices, elements, apparatuses, modules, units, etc., of this disclosure are described as having a purpose or performing an operation or function, they should be considered herein as being "configured" to satisfy that purpose or perform that operation or function. Each component, unit, controller, device, element, apparatus, module, etc. may individually embody or include a processor and memory (e.g., a non-transitory computer-readable medium) as part of an apparatus.

[0023] This disclosure provides an anode-free all-solid-state battery.

[0024] According to one embodiment of the present disclosure, an anode-free all-solid-state battery includes at least: an anode current collector; a first intermediate layer disposed on the anode current collector and including a first metal for forming a solid solution alloy with lithium; a second intermediate layer disposed on the first intermediate layer and including a second metal for forming an intermetallic alloy with lithium; a solid electrolyte layer disposed on the second intermediate layer; a cathode active material layer disposed on the solid electrolyte layer; and a cathode current collector disposed on the cathode active material layer.

[0025] All-solid-state batteries comprise a cathode active material layer bonded to a cathode current collector, an anode active material layer bonded to an anode current collector, and a solid electrolyte layer situated between the cathode and anode active material layers. However, in addition to the anode active material such as graphite, the anode active material layer also includes a solid electrolyte for transporting lithium ions, and this solid electrolyte has a higher specific gravity than liquid electrolytes. Therefore, the energy density of all-solid-state batteries is lower than that of lithium-ion batteries using liquid electrolytes.

[0026] As mentioned above, in order to increase the energy density of solid-state batteries, anode-free all-solid-state batteries of storage type have recently been explored and studied, so that lithium ions can be directly deposited on the anode current collector in the form of lithium metal.

[0027] Traditional anode-free all-solid-state batteries include an intermediate layer between a solid electrolyte layer and an anode current collector, and also include carbon material for uniformly depositing and plating lithium. When an anode-free all-solid-state battery is charged, lithium ions (Li) at the cathode... + Lithium ions (Li) reach the intermediate layer through the solid electrolyte layer. + The lithium reacts with carbon materials, migrates, and then precipitates between the anode current collector and the interlayer. However, when typical graphite is included as the carbon material in the interlayer of an anode-less all-solid-state battery, active lithium is consumed due to uncontrolled lithium dendrite growth and side reactions, and lithium ions precipitate between the solid electrolyte layer and the interlayer due to the crystallinity of graphite, causing internal short circuits. Therefore, the lifespan of the anode-less all-solid-state battery may be shortened.

[0028] According to one embodiment of this disclosure, an anode-free all-solid-state battery may include a first intermediate layer and a second intermediate layer. The first intermediate layer includes a first metal for forming a solid solution alloy with lithium, and the second intermediate layer includes a second metal for forming an intermetallic alloy with lithium. This prevents internal short circuits caused by the additional formation of a lithium plating layer between the solid electrolyte layer and the intermediate layer, thereby enabling the anode-free all-solid-state battery to be charged more stably.

[0029] The following is for reference. Figure 1 The components constituting an anode-free all-solid-state battery according to embodiments of the present disclosure are described in detail. Figure 1 This is a schematic diagram illustrating the charging state of an anode-free all-solid-state battery according to an embodiment of the present disclosure. Figure 1 Anode-free all-solid-state battery 1 in its initial state (in other words, its fully discharged state before initial charging) and anode-free all-solid-state battery 1' during charging are shown. Each component of the anode-free all-solid-state battery according to embodiments of this disclosure is described, with attention focused on the anode-free all-solid-state battery 1 in its initial state, unless otherwise defined.

[0030] Anode current collector

[0031] According to one embodiment of this disclosure, the anode current collector 10, used as a conductive plate-like substrate, may comprise a material that does not react with lithium. Specifically, the anode current collector 10 includes various materials without particular limitation, as long as the material is conductive without causing a chemical change in the associated battery (or the anode-free all-solid-state battery according to this disclosure). For example, the anode current collector 10 may be aluminum (Al), nickel (Ni), titanium (Ti), tungsten (W), iron (Fe), chromium (Cr), or stainless steel, or alloys thereof.

[0032] Intermediate layer

[0033] According to one embodiment of the present disclosure, the intermediate layer 20 is a component directly disposed on the anode current collector 10. When lithium ions are deposited on the surface of the anode current collector 10 in the form of lithium metal, the intermediate layer 20 can induce lithium metal to be electroplated in the horizontal direction along the surface of the anode current collector 10.

[0034] According to one embodiment of the present disclosure, the intermediate layer 20 may include a first intermediate layer 21 and a second intermediate layer 22 disposed on the first intermediate layer 21.

[0035] According to one embodiment of this disclosure, the first intermediate layer 21 (which is a component disposed directly on the anode current collector 10) may be a space for primary lithium plating during the charging process of an anode-free all-solid-state battery.

[0036] According to one embodiment of this disclosure, the first intermediate layer 21 may include a first metal for reacting with lithium ions to form a solid solution alloy. The solid solution alloy has a higher lithium ion diffusion coefficient than the intermetallic alloy in the second intermediate layer 22 described below. Therefore, lithium is first electroplated onto the first intermediate layer 21, thereby preventing the lithium plating from directly contacting the solid electrolyte layer 30. According to this disclosure, a solid solution alloy refers to an alloy phase in which at least one solid material is disorderedly mixed into another solid solvent without forming a new crystal structure.

[0037] According to one embodiment of this disclosure, the first metal may be magnesium (Mg), silver (Ag), cadmium (Cd), or an alloy thereof. Specifically, in one example, the first metal may be magnesium (Mg).

[0038] According to one embodiment of this disclosure, the first intermediate layer 21 can be formed by sputtering or by chemical vapor deposition.

[0039] According to one embodiment of this disclosure, the first intermediate layer 21 may have a thickness ranging from 100 nm to 3,000 nm. Specifically, in some examples, the first intermediate layer 21 has a thickness of at least 200 nm, at least 300 nm, at least 400 nm, at least 500 nm, or at least 600 nm. In some instances, the first intermediate layer 21 has a thickness of up to 2,800 nm, up to 2,600 nm, up to 2,400 nm, up to 2,200 nm, up to 2,000 nm, or up to 1,500 nm. When the first intermediate layer 21 satisfies one or more of the above ranges, lithium can be electroplated more efficiently.

[0040] According to one embodiment of this disclosure, the thickness of the first intermediate layer 21 can be greater than the thickness of the second intermediate layer 22. In this case, lithium electroplating can be performed more effectively.

[0041] According to one embodiment of this disclosure, the second intermediate layer 22 (which is a component directly disposed on the first intermediate layer 21) can induce lithium-ion electroplating on the first intermediate layer 21 and can prevent the solid electrolyte layer 30 from directly contacting the lithium plating layer, thereby preventing the growth of lithium dendrites.

[0042] According to one embodiment of this disclosure, the second intermediate layer 22 may include a second metal for reacting with lithium ions to form an intermetallic alloy. The intermetallic alloy has a lithium-ion diffusion coefficient lower than that of the solid solution alloy. Therefore, the intermetallic alloy can induce lithium to be electroplated first onto the first intermediate layer 21, thereby preventing direct contact between the lithium plating and the solid electrolyte layer 30. According to this disclosure, an intermetallic alloy refers to an alloy phase in which at least two metal elements are provided to form a crystal structure with a regular arrangement between the metal elements.

[0043] According to one embodiment of this disclosure, the second metal may be gold (Au), zinc (Zn), silicon (Si), tin (Sn), aluminum (Al), germanium (Ge), or alloys thereof. Specifically, in one example, the second metal may be gold (Au).

[0044] According to one embodiment of this disclosure, the second intermediate layer 22 can be formed by sputtering or by chemical vapor deposition.

[0045] According to one embodiment of this disclosure, the thickness of the second intermediate layer 22 may be less than the thickness of the first intermediate layer 21. In this case, regardless of the conductivity of the second intermediate layer 22, lithium can be more easily induced to be electroplated onto the first intermediate layer 21 first, thereby more easily preventing direct contact between the solid electrolyte layer 30 and the lithium plating.

[0046] According to one embodiment of this disclosure, the second intermediate layer 22 may have a thickness ranging from 5 nm to 50 nm. Specifically, in some examples, the second intermediate layer 22 may be at least 6 nm, at least 7 nm, at least 8 nm, at least 9 nm, at least 10 nm, or up to 48 nm, up to 46 nm, up to 44 nm, up to 42 nm, up to 40 nm, or up to 35 nm. When the thickness of the second intermediate layer 22 meets one or more of the above ranges, lithium electroplating can be more efficient.

[0047] According to one embodiment of this disclosure, the anode-free all-solid-state battery 1' during charging includes an intermediate layer 20', which includes a first intermediate layer 21' and a second intermediate layer 22'. The first intermediate layer 21' may be formed of a solid solution alloy 211 of lithium and a first metal. The second intermediate layer 22' may be formed of an intermetallic alloy 221 of lithium and a second metal.

[0048] According to one embodiment of this disclosure, the solid solution alloy 211 of lithium and a first metal may include a first metal 211M and lithium 211L. (See also...) Figure 1 The first metal 211M and lithium 211L can be randomly mixed in a solid solution alloy 211 of lithium and the first metal.

[0049] According to one embodiment of this disclosure, the lithium-second intermetallic alloy 221 may include a second metal 221M and lithium 221L. (See also...) Figure 1 The second metal 221M and lithium 221L can be regularly arranged in the lithium-second metal intermetallic alloy 221.

[0050] According to one embodiment of this disclosure, the solid solution alloy 211 of lithium and a first metal has a higher lithium-ion diffusion coefficient than the intermetallic alloy 221 of lithium and a second metal. Therefore, lithium can be induced to be electroplated onto a first intermediate layer 21' comprising the solid solution alloy 211 of lithium and the first metal. Furthermore, a second intermediate layer 22' is inserted between the first intermediate layer 21' and the solid electrolyte layer 30. When lithium is electroplated onto the first intermediate layer 21', the second intermediate layer 22' prevents the lithium plating from directly contacting the solid electrolyte layer 30.

[0051] According to one embodiment of this disclosure, the solid solution alloy 211 of lithium and a first metal has a density of at least 1.0 × 10⁻⁶. - 8 cm 2 The lithium-ion diffusion coefficient is approximately 2.0 × 10⁻⁶ / s. -8 cm 2 / s, at least 4.0×10 -8 cm 2 / s, at least 6.0×10-8 cm 2 / s, at least 8.0×10 -8 cm 2 / s, at least 1.0×10 -7 cm 2 / s, or at most 1.0×10 -5 cm 2 / s, up to 8.0×10 -6 cm 2 / s, maximum 6.0×10 -6 cm 2 / s, maximum 4.0×10 -6 cm 2 / s, maximum 2.0×10 - 6 cm 2 / s, or at most 1.0×10 -6 cm 2 / s. When the above conditions are met, lithium can be electroplated more efficiently.

[0052] According to one embodiment of this disclosure, the intermetallic alloy 221 of lithium and a second metal has a density of at least 1.0 × 10⁻⁶. - 10 cm 2 The lithium-ion diffusion coefficient is 1 / s, specifically, the lithium-ion diffusion coefficient can be up to 8.0 × 10⁻⁶. -11 cm 2 / s, maximum 6.0×10 -11 cm 2 / s, maximum 4.0×10 -11 cm 2 / s, maximum 2.0×10 -11 cm 2 / s, maximum 1.0×10 -11 cm 2 / s, or at least 2.0 × 10 -13 cm 2 / s, at least 4.0×10 -13 cm 2 / s, at least 6.0×10 -13 cm 2 / s, at least 8.0×10 -13 cm 2 / s, or at least 1.0 × 10 -12 cm 2 / s. When the above conditions are met, lithium can be electroplated more efficiently.

[0053] solid electrolyte layer

[0054] According to one embodiment of this disclosure, an anode-free all-solid-state battery may include a solid electrolyte layer 30. The solid electrolyte layer 30 may be inserted between the cathode active material layer 42 and the intermediate layer 20 to transfer lithium ions present between the cathode active material layer 42 and the anode current collector 10.

[0055] According to one embodiment of this disclosure, a solid electrolyte layer 30 may be disposed on an intermediate layer 20 and may include a solid electrolyte having lithium-ion conductivity. The solid electrolyte includes oxide-based solid electrolytes, sulfide-based solid electrolytes, polymer electrolytes, or combinations thereof, and in one example may include a sulfide-based solid electrolyte.

[0056] According to one embodiment of this disclosure, the sulfide-based solid electrolyte may include Li6PS5X (X = chlorine (Cl), bromine (Br), or iodine (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 gallium (Ga),) Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li x MO y (where 'x' and 'y' are positive numbers; M is P, Si, Ge, B, Al, Ga or indium (In)), or a combination thereof (where Li = lithium, P = phosphorus, S = sulfur, O = oxygen, B = boron).

[0057] cathode

[0058] According to one embodiment of the present disclosure, the cathode 40 may include a cathode current collector 41 and a cathode active material layer 42.

[0059] Specifically, the cathode current collector 41 may include various materials, but is not particularly limited, as long as the material is conductive without causing chemical changes in the relevant battery. For example, the cathode current collector 41 may be aluminum (Al), nickel (Ni), titanium (Ti), tungsten (W), iron (Fe), chromium (Cr), stainless steel, or alloys thereof.

[0060] According to one embodiment of this disclosure, the cathode active material layer 42 may include a cathode active material, a conductive material, and an adhesive.

[0061] According to one embodiment of this disclosure, lithium ions (Li) are allowed to... + The reversibly electroplated or released cathode active material may include lithium-metal composite oxides (or lithium-metal composite oxides). Specifically, the lithium-metal composite 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), or 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)), lithium-nickel-cobalt based oxides (e.g., LiNi) 1-Y1 Co Y1 O2 (0 < Y1 < 1)), lithium-manganese-cobalt based oxides (e.g., LiCo) 1-Y2 Mn Y2 O2 (0 < Y2 < 1) or LiMn 2-z1 Co z1 O4 (0 < Z1 < 2)), lithium-nickel-manganese-cobalt based oxides (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 lithium-nickel-cobalt-transition metal (M) oxides (e.g., Li(Ni) p2 Co q2 Mn r3 M S2O2 ('M' is Al, Fe, Vanadium (V), Cr, Ti, Ta, Mg and Mo; p2, q2, r3 and s2 are the 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 be a compound containing any one of the above materials or containing at least two of the above materials.

[0062] Among them, lithium composite metal oxides can be LiCoO2, LiMnO2, LiNiO2, lithium nickel manganese cobalt oxides (e.g., Li(Ni)O2), etc. 1 / 3 Mn 1 / 3 Co 1 / 3 O2, 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 lithium nickel cobalt aluminum oxide (e.g., Li(Ni) 0.8 Co 0.15 Al 0.05 Lithium nickel manganese cobalt oxide (LiNiO2) can be used to enhance the capacity characteristics and stability of the battery. When considering significantly improving the effect by controlling the type and content ratio of the components forming the lithium composite metal oxide, lithium nickel manganese cobalt oxide can be Li(NiO2)2. 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, may be used.

[0063] According to one embodiment of this disclosure, the cathode active material may include boron (B) or LiNbO (wherein Nb = niobium), and may further include a coating surrounding a lithium composite metal oxide. The inclusion of a coating can improve the structural stability of the cathode active material.

[0064] Furthermore, according to one embodiment of this disclosure, the cathode active material layer 42 may further include a solid electrolyte. The solid electrolyte can be coated onto the cathode active material. Therefore, the interfacial compatibility between the cathode active material layer 42 and the solid electrolyte layer 30 can be improved. The details of the solid electrolyte are the same as those of the solid electrolyte described above regarding the solid electrolyte layer 30. Therefore, the details of the solid electrolyte are omitted.

[0065] According to one embodiment of this disclosure, a conductive material can be used to further improve the conductivity of the cathode active material. The conductive material may include a variety of materials, without particular limitation, as long as the material is conductive without causing chemical changes in the relevant battery. 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 conductive materials such as polyphenylene derivatives.

[0066] According to one embodiment of this disclosure, the adhesive can promote bonding between the conductive material, the cathode active material, and the cathode 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, nitrile rubber, fluororubber, and various copolymers thereof.

[0067] The embodiments of this disclosure are described in detail so that those skilled in the art can readily reproduce them. However, this disclosure can be implemented in various forms and is not limited to the embodiments described herein.

[0068] Example 1

[0069] After preparing the anode current collector made of stainless steel foil, a 200 nm magnesium (Mg) thin film (first intermediate layer) was formed on the surface of the anode current collector by direct current (DC) sputtering. Then, a 30 nm gold (Au) thin film (second intermediate layer) was formed on the surface of the Mg thin film by DC sputtering, thereby fabricating the electrode. Furthermore, 100 mg of solid electrolyte powder including Li6PS5Cl was placed in a mold with an inner diameter of 10 mm and compressed at 200 MPa, thereby fabricating a solid electrolyte layer on the surface of the formed gold (Au) thin film. Subsequently, 20 mg of a cathode active material (LiNi) mixed with each other in a 70:28:2 ratio was compressed at 200 MPa.0.8 Co 0.1 Mn 0.1 O2), solid electrolyte (Li6PS5Cl) 0.5 Br 0.5 Powders of a conductive material (vapor-grown carbon fiber, VGCF) are used to form a cathode active material layer on a solid electrolyte layer. After preparing a cathode current collector with a thickness of 10 μm and including Al, the cathode current collector is matched with one surface of the prepared cathode active material layer, and the result is compressed at 380 MPa to form a cathode current collector, thereby preparing an anode-free all-solid-state battery.

[0070] Comparative Example 1

[0071] After preparing the anode current collector made of stainless steel foil, a 200 nm gold (Au) thin film (first intermediate layer) is formed on the surface of the anode current collector by DC sputtering. Then, a 30 nm Mg thin film (second intermediate layer) is formed on the surface of the Au thin film by DC sputtering, thereby fabricating the electrode. Furthermore, 90 mg of solid electrolyte powder including Li6PS5Cl is placed in a mold with an inner diameter of 10 mm and compressed at 200 MPa, thereby fabricating a solid electrolyte layer on the surface of the formed Mg thin film. Then, 20 mg of a cathode active material (LiNi) mixed with each other in a 70:28:2 ratio is compressed at 200 MPa. 0.8 Co 0.1 Mn 0.1 O2), solid electrolyte (Li6PS5Cl) 0.5 Br 0.5 Powders of a conductive material (VGCF) are used to form a cathode active material layer on a solid electrolyte layer. After preparing a cathode current collector with a thickness of 10 μm and including Al, the cathode current collector is matched with one surface of the prepared cathode active material layer, and the result is compressed at 380 MPa to form a cathode current collector, thereby preparing an anode-free all-solid-state battery.

[0072] Reference Example 1

[0073] After preparing an anode current collector made of stainless steel foil, a 30 nm gold (Au) thin film was formed on the surface of the anode current collector using a DC sputtering process. Furthermore, 100 mg of solid electrolyte powder including Li6PS5Cl was placed in a mold with an inner diameter of 10 mm and compressed at 380 MPa, thereby creating a solid electrolyte layer on the surface of the formed Au thin film. Subsequently, a lithium metal electrode was positioned on the solid electrolyte layer to form a counter electrode, thus fabricating an anode-free solid-state half-cell.

[0074] See Example 2

[0075] After preparing an anode current collector made of stainless steel foil, a 30 nm magnesium (Mg) thin film was formed on the surface of the anode current collector using a DC sputtering process. Furthermore, 100 mg of solid electrolyte powder including Li6PS5Cl was placed in a mold with an inner diameter of 10 mm and compressed at 380 MPa, thereby creating a solid electrolyte layer on the surface of the formed Mg thin film. Subsequently, a lithium metal electrode was positioned on the solid electrolyte layer to form a counter electrode, thus fabricating an anode-free solid-state half-cell.

[0076] Experimental Example 1

[0077] For each of the anode-free all-solid-state batteries manufactured according to Example 1 and Comparative Example 1, under conditions of 25°C and 20 MPa, at 1.0 mA / cm 2 At a current density of 1.0 mA / cm², electroplating exhibits [results]. 2 Following the lithium capacity, scanning electron microscopy (SEM) images and energy-dispersive X-ray spectroscopy (EDS) spectra of the electrode cross-section were obtained via SEM-EDS. Figure 2 As shown in the diagram, the JSM-7800F Prime from JEOL is used as the SEM-EDS device.

[0078] refer to Figure 2 It can be recognized that in the anode-free all-solid-state battery according to Example 1, the lithium-plated area and the solid electrolyte area are clearly distinguished from each other. Therefore, it can be recognized that no lithium dendrites are formed because direct contact between the lithium plating and the solid electrolyte area is prevented. Conversely, it is recognized that in the anode-free all-solid-state battery according to Comparative Example 1, the lithium-plated area and the solid electrolyte area are mixed together. Therefore, it can be recognized that lithium dendrites are formed because the lithium plating is in direct contact with the solid electrolyte area. This phenomenon is expected to be caused by the lithium-ion diffusion coefficient of the Li-Mg alloy (in the solid alloy phase), which is higher than that of the Li-Au alloy (in the intermetallic alloy phase).

[0079] Experiment Example 2

[0080] Under conditions of 25℃ and 20MPa, at 1.0mA / cm 2 At a current density, anode-free all-solid-state batteries manufactured according to each of Reference Example 1, Reference Example 2, Example 1, and Comparative Example 1 were charged, and the voltage-area capacity curves are shown in the figure. Figure 3 and Figure 4 middle.

[0081] refer to Figure 3 and Figure 4It can be recognized that the anode-free all-solid-state battery according to Example 1 dominates the lithium alloying reaction with the Mg film, without the voltage behavior resulting from the lithium alloying reaction with the Au film. Furthermore, it can be recognized that the anode-free all-solid-state battery according to Comparative Example 1 exhibits a lithium alloying reaction with the Au film after the initial lithium alloying reaction with the Mg film. Therefore, it can be recognized that the lithium alloying reaction is more advantageous for the Mg film than the Au film. Moreover, it can be recognized that since the Mg film is positioned adjacent to the anode current collector, lithium is first electroplated at the portion adjacent to the anode current collector.

[0082] Experimental Example 3

[0083] In CC-CV mode, at 25°C, with a current of 0.1C (1C = 3.5mA / cm²), 2 Each of the anode-free all-solid-state batteries according to Example 1 and Comparative Example 1 was charged to 4.2V and at 0.1C (1C = 3.5mA / cm). 2 Discharge to 2.5V. In this case, Figure 5 The figure shows a graph representing the relationship between voltage and specific capacity.

[0084] In CC-CV mode, at 25°C, during cycles 1 to 5, at 0.1°C (1°C = 3.5 mA / cm²), 2 Under these conditions, each of the anode-free all-solid-state batteries according to Example 1 and Comparative Example 1 was charged to 4.2V and subjected to 0.1C (1C = 3.5mA / cm). 2 Discharged to 2.5V in CC-CV mode at 25°C for cycles 6 through 10 at 0.3C (1C = 3.5mA / cm). 2 Charged to 4.2V at 0.3C (1C = 3.5mA / cm) and then at 0.3C (1C = 3.5mA / cm). 2 Discharged to 2.5V in CC-CV mode at 25°C for cycles 11-15 at 0.5C (1C = 3.5mA / cm). 2 Charged to 4.2V at 0.5C (1C = 3.5mA / cm) and then at 0.5C (1C = 3.5mA / cm). 2 Discharged to 2.5V in CC-CV mode at 25°C for cycles 16-20, at 1C (=3.5mA / cm). 2 Charged to 4.2V under 1C (=3.5mA / cm) and then at 1C (=3.5mA / cm) 2 Discharged to 2.5V in CC-CV mode at 25°C for cycles 21 to 25 at 0.1C (1C = 3.5mA / cm). 2Charged to 4.2V at 0.1C (1C = 3.5mA / cm) and then at 0.1C (1C = 3.5mA / cm). 2 Discharged to 2.5V. In this case, a graph showing the specific capacity for each cycle is provided. Figure 6 As shown in the image.

[0085] refer to Figure 5 It can be recognized that, compared with the anode-free all-solid-state battery according to Comparative Example 1, the anode-free all-solid-state battery according to Example 1 exhibits superior charge / discharge capacity. Furthermore, refer to... Figure 6 It can be recognized that the anode-free all-solid-state battery according to Comparative Example 1 caused an internal short circuit in the 12th cycle, but the anode-free all-solid-state battery according to Example 1 was charged without considering the charge / discharge rate.

[0086] As described above, according to embodiments of the present disclosure, since an additional lithium plating layer is formed between the solid electrolyte layer and the intermediate layer, the anode-free all-solid-state battery can prevent internal short circuits and can be charged more stably even during higher rate charging / discharging.

[0087] Although this disclosure has been described with reference to embodiments and accompanying drawings, it is not limited thereto, but various modifications and alterations can be made by those skilled in the art to which this disclosure pertains without departing from the spirit and scope of this disclosure as claimed in the appended claims.

Claims

1. An anode-free all-solid-state battery, comprising: Anode current collector; A first intermediate layer is disposed on the anode current collector, the first intermediate layer comprising a first metal configured to form a solid solution alloy with lithium; A second intermediate layer is disposed on the first intermediate layer, the second intermediate layer comprising a second metal configured to form an intermetallic alloy with lithium; A solid electrolyte layer is disposed on the second intermediate layer; A cathode active material layer is disposed on the solid electrolyte layer; as well as The cathode current collector is arranged on the cathode active material layer.

2. The anode-free all-solid-state battery according to claim 1, wherein, The first metal is at least one selected from magnesium (Mg), silver (Ag), cadmium (Cd), magnesium (Mg) alloys, silver (Ag) alloys, and cadmium (Cd) alloys.

3. The anode-free all-solid-state battery according to claim 1, wherein, The second metal is selected from at least one of gold (Au), zinc (Zn), silicon (Si), tin (Sn), aluminum (Al), germanium (Ge), gold (Au) alloy, zinc (Zn) alloy, silicon (Si) alloy, tin (Sn) alloy, aluminum (Al) alloy, and germanium (Ge) alloy.

4. The anode-free all-solid-state battery according to claim 1, wherein, The first intermediate layer comprises a solid solution alloy of lithium and the first metal, and The second intermediate layer comprises an intermetallic alloy of lithium and the second metal.

5. The anode-free all-solid-state battery according to claim 4, wherein, The lithium-ion diffusion coefficient of the solid solution alloy of lithium and the first metal is higher than that of the intermetallic alloy of lithium and the second metal.

6. The anode-free all-solid-state battery according to claim 4, wherein, The solid solution alloy of lithium and the first metal has a density of at least 1.0 × 10⁻⁶. -8 cm 2 The lithium-ion diffusion coefficient is 1 / s.

7. The anode-free all-solid-state battery according to claim 4, wherein, The intermetallic alloy of lithium and the second metal has a density of at least 1.0 × 10⁻⁶. -10 cm 2 The lithium-ion diffusion coefficient is 1 / s.

8. The anode-free all-solid-state battery according to claim 1, wherein, The thickness of the first intermediate layer is greater than the thickness of the second intermediate layer.

9. The anode-free all-solid-state battery according to claim 1, wherein, The first intermediate layer has a thickness in the range of 100 nm to 3,000 nm.

10. The anode-free all-solid-state battery according to claim 1, wherein, The second intermediate layer has a thickness in the range of 5 nm to 50 nm.

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