Anode for a solid-state battery, method for producing an anode for a solid-state battery and solid-state battery comprising it

Abstract

An anode for a solid-state battery, a method for its fabrication, and a solid-state battery incorporating the anode are provided. The anode comprises an anode current collector, a lithium-friendly metal layer stacked on the anode current collector, and an anode active material layer stacked on the lithium-friendly metal layer, wherein the anode active material layer contains a silicon-based anode active material.

Description

TECHNICAL AREA

[0001] The present disclosure relates to an anode for a solid-state battery which is operated stably without a cell short circuit under a higher capacity condition, since the lithium deposition is induced stably without the growth of lithium dendrites even when it is overloaded beyond the theoretical capacity, a method for its manufacture and the anode for the solid-state battery. BACKGROUND

[0002] Recently, secondary batteries have been widely used in various applications, such as electric vehicles and portable electronic devices. In particular, the active development of solid-state batteries has been pursued to achieve higher energy density (Wh / L). The development of such solid-state batteries has focused on improving stability by replacing the existing liquid electrolyte with a solid electrolyte, as well as on improving the energy density and lifespan of the solid-state battery.

[0003] However, if a cathode with a higher capacity is used to increase the energy density of the solid-state battery, the anode should be significantly thicker than the cathode. A thicker anode increases the volume and weight of a cell, which represents a physical size limitation when increasing the overall energy density. Furthermore, excessive differences in the proportions between the cathode and anode can lead to irregular lithium precipitation and accelerate dendrite formation and cell degradation. Consequently, the stability of the solid-state battery may decrease over extended periods of operation.

[0004] Accordingly, there remains a need to develop an anode material capable of maintaining a higher capacity for the deposition and release of lithium ions while simultaneously achieving a balance with a higher-capacity cathode material to increase the energy density of the solid-state battery, and to develop an anode structure capable of preventing the growth of lithium dendrites and maintaining stable charge / discharge characteristics. SUMMARY

[0005] The present disclosure addresses the aforementioned problems of the prior art, while retaining the advantages of the technology.

[0006] One aspect of the present disclosure provides an anode (e.g. for a solid-state battery) capable of stably inducing lithium deposition without the growth of lithium dendrites (e.g. even under overcharging), a method for its manufacture, and a solid-state battery containing this anode.

[0007] In another aspect of the present disclosure, a structure of an anode is provided, comprising an anode active material layer with a lithium-friendly metal layer and a silicon-based anode active material stacked on the lithium-friendly metal layer. During charging, the anode is capable of inducing the deposition of lithium beneath the layer of anode active material.

[0008] The technical problems addressed by the present disclosure are not limited to the problems mentioned above, and any other technical advantages provided by the disclosure and not expressly mentioned here will be clearly understood by those skilled in the art in light of the following description.

[0009] In general, the present disclosure provides an anode for a solid-state battery, a method for its manufacture, and a solid-state battery that uses it.

[0010] In some embodiments (1) the present disclosure provides an anode for a solid-state battery comprising an anode current collector, a lithium-friendly metal layer stacked on the anode current collector, and an anode active material layer stacked on the lithium-friendly metal layer, wherein the anode active material layer comprises a Si-based anode active material.

[0011] In some embodiments (2) the present disclosure provides an anode for a solid-state battery in (1) wherein the Si-based anode active material has a theoretical electrochemical capacity of at least 100 mAh / g.

[0012] In some embodiments, (3) the present disclosure provides an anode for a solid-state battery in (1) or (2), wherein the Si-based anode active material comprises a complex of Si or an active material selected from the group consisting of Si and graphite, lithium titanate (LTO), graphene, silicon-based oxide (SiOx) and a metal oxide.

[0013] In some embodiments, (4) the present disclosure provides an anode for a solid-state battery in one of (1) to (3) wherein the anode active material is Si-based and is a Si-graphite complex.

[0014] In some embodiments, (5) the present disclosure provides an anode for a solid-state battery in one of (1) to (4) wherein the anode active material layer also contains a binder.

[0015] In some embodiments, (6) the present disclosure provides an anode for a solid-state battery in a version of (1) to (5) wherein an active material loading amount of the anode active material layer is in the range of 0.2 mg / cm² 2 up to 1.8 mg / cm² 2 lies.

[0016] In some embodiments, (7) the present disclosure provides an anode for a solid-state battery in one of (1) to (6) wherein the anode active material layer further comprises a solid electrolyte.

[0017] In some embodiments, (8) the present disclosure provides an anode for a solid-state battery in one of (1) to (7) in which the lithium-friendly metal layer comprises at least one type selected from the group consisting of Mg, Ag, Zn, Au, Ni, Co, Mn, Al, Cd and Ti.

[0018] In some embodiments, (9) the present disclosure provides an anode for a solid-state battery in one of (1) to (8) wherein the lithium-friendly metal layer contains Mg.

[0019] In some embodiments, (10) the present disclosure provides an anode for a solid-state battery in one of (1) to (9) in which the lithium-friendly metal layer has a thickness of 10 nm to 5,000 nm.

[0020] In some embodiments (11) the present disclosure provides an anode for a solid-state battery in a from (1) to (10) wherein the lithium coating takes place under the alloy of the lithium-friendly metal layer and the lithium formed in an overcharge state.

[0021] In some embodiments (12) the present disclosure provides a method for producing an anode for a solid-state battery, which includes depositing a lithium-friendly metal layer on an anode current collector (S1), producing an anode active material slurry containing Si (S2), and forming an anode active material layer by applying the anode active material slurry to the lithium-friendly metal layer and drying the result (S3).

[0022] In some embodiments, (13) the present disclosure provides a method for producing an anode for a solid-state battery in (12) wherein S1 is carried out by a physical vapor deposition process.

[0023] In some embodiments, (14) the present disclosure provides a method for producing an anode for a solid-state battery in (12) or (13) wherein the anode active material slurry has a viscosity of 100 cP and 200 cP in S2.

[0024] In some embodiments, (15) the present disclosure provides a method for producing an anode for a solid-state battery in a process from (12) to (14) wherein the drying in S3 is carried out at a temperature of 70°C to 120°C.

[0025] In some embodiments, (16) the present disclosure provides a solid-state battery according to (1). BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and other tasks, features and advantages of the present disclosure will become clearer from the following detailed description in conjunction with the accompanying drawings: The Fig. 1A and Fig. Figure 1B shows representations of the precipitation of lithium when an anode is charged, according to an embodiment of the present disclosure and comparative example 1; The Fig. 2A and Fig. 2B are SEM-EDS views showing a cross-section of an electrode at 100% of the state of charge (SOC) of a cell using an anode according to an embodiment of the present disclosure or comparative example 1; The Fig. Figure 3A is a view which, in the form of a diagram, shows an electrochemical characteristic of an anode according to an embodiment of the present disclosure and comparative example 1; The Fig. Figure 3B is a view which shows in the form of a diagram a coulombic efficiency when the cycle of an anode is repeated according to an embodiment of the present disclosure and comparative example 2; The Fig. 4A and Fig. 4B are views which, in the form of a diagram, represent a voltage curve during the charging of an anode according to an embodiment of the present disclosure and comparative example 1; and The Fig. 5A, Fig. 5B and Fig. Figure 5C are views which, in the form of a diagram, show an electrochemical characteristic of a cell which uses an anode according to an embodiment of the present disclosure and comparative example 1. DETAILED DESCRIPTION

[0027] The present revelation is described in more detail below.

[0028] The terminology or words used in this description and the claims are not to be understood as generally accepted dictionary definitions, but should be interpreted based on the technical scope of this disclosure. Unless expressly defined in the description, all terms are to be understood as having their usual and ordinary meanings as used in the relevant technology, unless otherwise specified or redefined by the inventor to best explain this disclosure. Anode for solid-state battery

[0029] The present disclosure provides an anode, e.g., for a solid-state battery or cell, comprising an anode current collector, a lithium-friendly metal layer stacked on the anode current collector, and an anode active material layer stacked on the lithium-friendly metal layer. The anode active material layer comprises a silicon-based anode active material.

[0030] The components of the anode for the solid-state battery are described in more detail below. anode current collector

[0031] According to the present disclosure, the anode current collector gathers a current that enables electrons to move to an external circuit of the solid-state battery and provides higher electrical conductivity so that the electrons move quickly. The type of anode current collector is not specifically limited, as long as the anode current collector possesses conductivity without causing chemical changes to the cell. In some non-restrictive embodiments, the anode current collector may comprise at least one of copper, stainless steel, aluminum, nickel, titanium, sintered carbon, a surface-treated material comprising copper or stainless steel surface-treated with carbon, nickel, titanium, or silver, or an aluminum-cadmium alloy, or combinations thereof.

[0032] According to the embodiments of the present disclosure, the thickness of the anode current collector is not specifically limited, as long as the thickness of the anode current collector ranges from 8 µm to 25 µm and, in some preferred embodiments, from 10 µm to 20 µm. According to the present disclosure, as long as the anode current collector meets the thickness condition, a higher energy density can be maintained without damaging the anode current collector. Anode active material layer

[0033] According to one embodiment, the anode active material layer is stacked on the lithium-friendly metal layer and configured to allow lithium ions to react uniformly across the entire electrode surface during charging. The anode active material layer may contain a silicon-based anode active material. The theoretical electrochemical capacity of the anode active material can range from 100 mAh / g to 5,000 mAh / g. Preferably, the theoretical electrochemical capacity can be at least 500 mAh / g or at least 800 mAh / g and at most 4,500 mAh / g or at most 4,000 mAh / g. Since the theoretical capacity of the anode active material meets the aforementioned range, the overall energy density of the cell can be increased. Furthermore, since many charging cycles are stored and discharged under higher current density conditions, the cell's performance under higher power conditions can be improved.Accordingly, the energy efficiency of the cell can be improved.

[0034] In some embodiments, the silicon-based anode active material comprises silicon or a silicon complex with one or more materials selected from graphite, lithium titanate (LTO), graphene, silicon-based oxide (SiOx), and a metal oxide. Particularly preferably, the silicon-based anode active material can be a silicon-graphite complex. When the silicon-graphite complex is used as the anode active material, silicon particles present between graphite particles facilitate the diffusion of lithium ions between the graphite particles, thus increasing lithium ion diffusion. Consequently, lithium deposition can occur more easily, thereby increasing the probability of supercharged lithium precipitation.

[0035] According to embodiments of the present disclosure, the active material loading amount in the active anode material layer can be 0.2 mg / cm². 2 up to 1.8 mg / cm² 2 sufficient, and preferably at least 0.3 mg / cm² 2 , at least 0.4 mg / cm² 2 or at least 0.5 mg / cm² 2 and at most 1.4 mg / cm² 2 , at most 1.2 mg / cm² 2 or at most 1.0 mg / cm² 2 If the amount of active material loaded in the anode active material layer meets the above range, the energy density and performance characteristics of the cell can be improved, and the stress on the electrode can be reduced to improve the cycle life.

[0036] According to the embodiments of the present disclosure, the anode active material may additionally contain a binder. The binder may contain various materials without any specific limitation, as long as the various materials fix the materials of the anode active material layer. In some preferred embodiments, the binder may contain at least one of polytetrafluoroethylene, polyethylene oxide, polyethylene glycol, polyacrylonitrile, polyvinyl chloride, polymethyl methacrylate, polypropylene oxide, polyphosphazene, polysiloxane, polydimethylsiloxane, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP), polyvinylidene fluoride-chlorotrifluoroethylene copolymer (PVDF-CTFE), polyvinylidene fluoride-tetrafluoroethylene copolymer (PVDF-TFE), polyvinylidene carbonate, polyvinylpyrrolidinone, styrene-butadiene rubber, nitrile-butadiene rubber, or hydrogenated nitrile-butadiene rubber, or combinations thereof.

[0037] According to embodiments of the present disclosure, the anode active material layer may additionally contain a solid electrolyte. The solid electrolyte may be an inorganic solid electrolyte, such as a sulfide-based solid electrolyte, an oxide-based solid electrolyte, or a halide-based solid electrolyte, or a solid polymer electrolyte.

[0038] The sulfide-based solid electrolyte can be any of the general sulfide-based solid electrolytes without being specifically limited. In some preferred embodiments, the sulfide-based solid electrolyte can be at least one of Li₂S-P₂S₅, Li₂S-P₂S₅-LiI, Li₂S-P₂S₅-LiCl, Li₂S-P₂S₅-LiBr, Li₂S-P₂S₅-Li₂O, Li₂S-P₂S₅-Li₂O-LiI, Li₂S-SiS₂, Li₂SSiS₂-LiI, Li₂S-SiS₂-LiBr, Li₂S-SiS₂-LiCl, Li₂S-SiS₂-B₂S₃-LiI, Li₂ S -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), or Li 10 GeP2S 12 or combinations thereof.

[0039] The oxide-based solid electrolyte can be any of the general oxide-based solid electrolytes, without being specifically limited. In some preferred embodiments, the oxide-based solid electrolyte can be at least one of Li 1+x+y Al x Ti 2-x Si y P 3-y O 12 (where 0 <x<2, 0≤y<3), BaTiO3, Pb(Zr,Ti)O3(PZT), Pb 1-x La x Zr 1-y Ti y O3 (PLZT) (where 0≤x<1, 0≤y<1), PB(Mg3Nb 2 / 3 )O3-PbTiO3(PMN-PT), HfO2, SrTiO3, SnO2, CeO2, Na2O, MgO, NiO, CaO, BaO, ZnO, ZrO2, Y2O3, Al2O3, TiO2, SiO2, Li3PO4, Li x Ti y(PO4)3 (where 0 <x<2, 0<y<3), Li x Al y Ti z (PO4)3 (where 0 <x<2, 0<y<1, 0<z<3), Li 1+x+y (Al, Ga) x (Ti, Ge) 2-x Si y P 3-y O 12 (where 0≤x≤1, 0≤y≤1) , Li x La y TiO3 (where 0 <x<2, 0<y<3), Li2O, LiOH, Li2CO3, LiAlO2, Li2O-Al2O3-SiO2-P2O5-TiO2-GeO2, Li 3+x La3M2O 12 (where “M” = Te, Nb, or Zr; 0≤x≤10), or Li7La3Zr 2-x Ta x O 12 (where 0 <x<2, LLZ-Ta), oder Kombinationen davon enthalten.

[0040] The solid polymer electrolyte is not specifically limited as long as the solid polymer electrolyte is a general solid polymer electrode. In some preferred embodiments, the solid polymer electrolyte can be at least one of: poly(diallyldimethylammonium) TFSI), Cu3N, Li3N, LiPON, Li3PO4, Li2S·SiS2, Li2S·GeS2·Ga2S3, Li2O·11Al2O3, Na2O·11Al2O3, (Na, Li) 1+x Ti 2-x Al x (PO4)3 (where 0.1≤x≤0.9), Li1+x Hf 2-x Al x (PO4)3 (where 0.1≤x≤0.9), Na3Zr2Si2PO 12 , Li3Zr2Si2PO 12 , Na5ZrP3O 12 , Na5TiP3O 12 , Na3Fe2P3O 12 , Na4NbP3O 12 , Na-silicate, Li 0,3 La 0,5 TiO3, Na5MSi4O 12 (where "M" is a rare earth element such as Nd, Gd or Dy), Li5ZrP3O 12 , Li5TiP3O 12 , Li3Fe2P3O 12 , Li4NbP3O 12 , Li 1+x (M, Al, Ga) x (Ge 1-y Ti y ) 2-x (PO4)3 (where x≤0.8; 0≤y≤1.0; ; “M” is Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm or Yb) , Li 1+x+y Q x Ti 2-x Si y P 3-y O 12 (where 0 <x≤0,4; 0<y≤0,6; „Q“ ist Al oder Ga), Li6BaLa2Ta2O 12 , Li 7r La3Zr2O 12 , Li5La3Nb2O 12 , Li5La3M2O 12 (where “M” is Nb or Ta), or Li 7+x A x La 3-x Zr2O 12(where 0 <x<3; „A“ ist Zn), oder Kombinationen davon enthält.

[0041] In some embodiments, the solid halide electrolyte can contain a Li element, an M element (where "M" is a metal other than Li), and an X element (where "X" is a halogen). In some embodiments, "X" can be, for example, F, Cl, Br, and I. In further embodiments, the solid halide electrolyte is preferably at least one of Br or Cl. In some embodiments, "M" can be a metal element, such as Sc, Y, B, Al, Ga, or In.

[0042] According to the embodiments of the present disclosure, the anode-active material layer may also contain a conductive material. The conductive material may include various conductive materials without any specific limitation, as long as the conductive materials improve the electrical conductivity of the anode-active material layer without causing the chemical modification. As non-limiting examples, the conductive material may include at least one of the following: carbon-based material, such as natural graphite, synthetic graphite, carbon black, acetylene black, Ketjen black, carbon fibers, and a carbon nanotube; metal-based material in the form of metal powders or metal fibers containing copper, nickel, aluminum, or silver; and a conductive polymer, such as polyphenylene derivatives. Lithium-friendly metal layer

[0043] According to one embodiment, the lithium-friendly metal layer is positioned beneath the anode active material layer. Accordingly, the lithium-friendly metal layer attracts lithium in an overcharged state to form an alloy and deposit lithium metal beneath the alloy. Furthermore, the lithium-friendly metal layer contains a metal that exhibits excellent interaction with lithium. Consequently, during lithium ion deposition, the lithium-friendly metal layer ensures an improved or more stable energy state, causing the lithium ions to deposit uniformly between the alloy and the anode current collector, thus triggering a uniform electrochemical reaction and stabilizing the anode active material.

[0044] The lithium-friendly metal layer can contain metal with an overvoltage in the range of 1 mV to 50 mV when charging at a current density of 1 mA / cm². 2 This occurs at normal temperature. In some embodiments, the overvoltage can be measured by charging / discharging a half-cell with a constant current under the condition of a voltage of at least 0.1 V. If the metal contained in the lithium-compatible metal layer meets the required range, energy loss can be reduced and the overvoltage in the electrochemical reaction improved, thus increasing the cycle life. Furthermore, charging remains stable even at higher current densities.

[0045] The lithium-friendly metal layer can, in particular, contain at least one of Mg, Ag, Zn, Au, Ni, Co, Mn, Al, Cd, or Ti. If the lithium-friendly metal layer contains at least one of these elements, the reaction between the lithium-friendly metal layer and lithium can be actively carried out, and a lithium deposition reaction can be performed on the lithium-friendly metal layer. In preferred embodiments, the lithium-friendly metal layer can contain Mg.

[0046] According to embodiments of the present disclosure, the lithium-friendly metal layer can have a thickness of 10 nm to 5,000 nm. In preferred embodiments, the lithium-friendly metal layer can have a thickness of at least 50 nm, at least 70 nm, or at least 100 nm, or at most 1,000 nm, at most 700 nm, or at most 500 nm. If the thickness of the lithium-friendly metal layer meets this range, lithium can be stably induced and deposited without significantly reducing the energy density. Method for manufacturing an anode for a solid-state battery

[0047] The present disclosure provides in embodiments a method (which may be referred to below as a “manufacturing method”) for the production of an anode (e.g. for a solid-state battery) which includes the deposition of a lithium-friendly metal layer on an anode current collector (S1), the preparation of an anode active material slurry containing Si (S2), and the formation of an anode active material layer by applying the slurry to the lithium-friendly metal layer and drying the result (S3).

[0048] The manufacturing process according to some embodiments of the present disclosure is described in more detail below. Deposition of a lithium-friendly metal layer (S1)

[0049] In the process for manufacturing the anode for the solid-state battery according to the present disclosure, ‘S1’ refers to the deposition of the lithium-friendly metal layer on the anode current collector.

[0050] The deposition according to embodiments of the present disclosure can be carried out by a sputtering process, an evaporation process, a chemical vapor deposition process, an electrophoretic deposition process, an electroplating process, an atomic layer deposition process, and / or a physical vapor deposition process. In preferred embodiments, the deposition can be carried out by the physical vapor deposition process. When the deposition is carried out by the physical vapor deposition process, the lithium-friendly metal layer can be obtained with higher purity. Accordingly, the lithium-friendly metal layer can be strongly bonded, and the thickness of a thin film can be precisely controlled.

[0051] The description relating to the anode current collector and the lithium-friendly metal layer of the solid-state battery anode described above also applies to the anode current collector and the lithium-friendly metal layer in this step. Preparation of the anode active material slurry (S2)

[0052] In embodiments of the method for producing the anode for the solid-state battery according to the present disclosure, “S2” refers to the production of an anode active material slurry containing Si.

[0053] In embodiments, the slurry according to the present disclosure can comprise a silicon-based anode active material, a binder, and a solvent. The description relating to the anode active material and the binder of the solid-state battery anode described above also applies to the anode active material and the binder.

[0054] The solvent may include various solvents without specific limitation, as long as the solvents dissolve the anode active material and the binder. In some embodiments, the solvent may contain at least one of N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), dimethyl sulfoxide (DMSO), tetrahydrofuran (THF), ethanol, isopropanol (IPA), acetone, ethylene carbonate (EC), propylene carbonate (PC), butyl butyrate (BB), xylene, or toluene, or combinations thereof.

[0055] In certain cases, the slurry can have a solids content of between 50 and 70 parts by weight (i.e., 50-70 wt%). In such embodiments, the solids content in the slurry can ensure a uniformly shaped slurry.

[0056] In some further embodiments, the slurry can have a viscosity in the range of 50 cP to 400 cP. Preferably, the slurry can have a viscosity of 100 cP to 200 cP. In such embodiments, the viscosity of the slurry can ensure a uniform mixture, and the slurry can be applied to the anode current collector with a uniform thickness. Formation of the anode active material layer (S3).

[0057] In some embodiments of the method for producing the anode for the solid-state battery according to the present disclosure, “S3” refers to forming the anode active material layer by applying the slurry produced in S2 to the lithium-friendly metal layer deposited in S1 and drying the result.

[0058] The application of the slurry according to the present disclosure is not specifically limited as long as the slurry is applied uniformly to the lithium-friendly metal layer.

[0059] In some embodiments, drying may involve drying the applied layer to evaporate the solvent, thereby forming the anode-active material layer. The drying process is not specifically limited, as long as the solvent is evaporated. For example, drying may be carried out by an air drying process, an oven drying process, a vacuum drying process, or a microwave drying process.

[0060] Drying can be carried out at a temperature of 70°C to 120°C. In some preferred embodiments, drying can be carried out at a temperature of at least 80°C or at least 90°C and at most 110°C or at most 100°C. In such embodiments, the temperature range can ensure a more uniformly dried product and minimize the amount of residual solvent, thus reducing any unstable electrochemical state and improving or optimizing the electrical and ionic conductivity of the anode. Solid state battery

[0061] In certain embodiments, the present disclosure provides a solid-state battery with the anode.

[0062] The solid-state battery according to the present disclosure may contain the anode of the solid-state battery according to the present disclosure, a cathode and a solid electrolyte layer.

[0063] The solid electrolyte layer can contain a solid electrolyte and a binder. The description of the solid electrolyte and binder contained in the anode described above also applies to the solid electrolyte and binder.

[0064] In embodiments, the cathode may comprise a cathode active material layer deposited onto a current collector, and the active cathode material layer may contain a cathode active material, a binder, a conductive material, and a solid electrolyte. The description relating to the solid electrolyte, binder, and conductive material in the anode described above also applies to the solid electrolyte, binder, and conductive material in the anode described above. In some embodiments, the cathode active material may include various materials without specific limitation, as long as the materials are deposited onto a cathode in a typical solid-state battery and reversibly absorb and release lithium ions.

[0065] An illustrative embodiment of the present disclosure is described in more detail in the following embodiments and examples. However, it is clear that the embodiments and examples presented do not limit the scope of the present disclosure or the appended claims. embodiment

[0066] In accordance with embodiments of the above disclosure, the embodiment was manufactured as follows: (S1) The lithium-friendly metal layer was deposited by depositing magnesium (Mg) onto the anode current collector, which contains stainless steel, using a physical vapor deposition (PVD) process. (S2) The anode active material slurry was prepared with a viscosity of 100 cP by mixing butyl butyrate (BB), which serves as a solvent, with Si, graphite and the solid electrolyte (LPSCI). (S3) The anode active material slurry produced in S2 was applied to the lithium-friendly metal layer, and the result was dried at a temperature of 100°C, so that the anode active material layer containing the Si-graphite complex serving as the active material is deposited on the lithium-friendly metal layer containing Mg, thereby producing the anode for the solid-state battery. Comparative example 1

[0067] In comparison to the embodiment above, the anode for the solid-state battery was manufactured in the same way as that of the embodiment, except that no Mg was deposited on the anode current collector. Comparative example 2

[0068] In comparison to the embodiment above, the anode for the solid-state battery was manufactured in the same way as that of the embodiment, except that Si is not included in the anode active material slurry. Experimental example 1: Evaluation for the cell - electrode cross-section at 100% state of charge (SOC)

[0069] In the present experiment, the solid-state battery was fabricated using LPSCI as the solid electrolyte, NCM811 coated with LiNbO3 as the cathode, and Al for the cathode current collector. The solid-state battery was then fully charged at a temperature of 25°C and a pressure of 20 MPa. The cross-sections of a lithium-coated electrode, which holds 3.5 mAh / cm², were then measured. 2 corresponds to are in the Fig. 2A and Fig. 2B is shown.

[0070] As in the Fig. 2A and Fig. As can be seen in Figure 2B, the embodiment in which the Si-graphite complex was used as the anode active material showed that lithium was uniformly deposited beneath the anode active material layer, regardless of the charge level of the anode active material, thereby preventing direct contact between the lithium metal and the solid electrolyte. In contrast to Comparative Example 1, in the absence of the lithium-friendly metal layer, it was observed that lithium precipitated in the electrode (or the anode). Accordingly, it can be seen that, according to the present disclosure, the lithium-friendly metal layer attracts lithium that precipitates due to overcharging to be deposited between the anode active material layer and the lithium-friendly metal layer. Experimental example 2: Evaluation of the electrochemical characteristics for the half-cell

[0071] In this experiment, a half-cell was formed using the solid-state battery anode produced in the embodiment described above and in Comparative Example 1, and the electrochemical properties of the half-cell were evaluated. In short, the half-cell was formed using the solid-state battery anode produced in the embodiment described above and in Comparative Example 1, LPSCI, and lithium metal, and the charge / discharge conditions were set to a range of 0 V to 0.1 V. Furthermore, this experiment was conducted under conditions where the temperature was 25°C, the pressure 20 MPa, and the anode active material loading was 0.8 mg / cm². 2 was and the current density for evaluation at 1.0 mA / cm² 2 was held. Afterwards, a voltage characteristic (v) was measured during charging / discharging with capacities of 1 mAh / cm². 2 and 3.5 mAh / cm² 2, the coulombic efficiency (CE; %) as a function of a charge / discharge cycle, a cumulative CE (%) and a voltage curve during charging in Fig. 3A, Fig. 4A and Fig. 4B shown in the form of diagrams.

[0072] As in Fig. As can be seen from 3A, an electrode that uses the anode according to an embodiment of the present disclosure performs charging / discharging under the condition of the higher capacity of 3.5 mAh / cm². 2 The anode terminated earlier than an anode according to the comparative example. Accordingly, the anode according to one embodiment of the present disclosure showed an initial efficiency that is better than that of the anode according to the comparative example. Furthermore, it can be seen that the electrode according to one embodiment of the present disclosure also performed better under the condition of the higher capacity of 3.5 mAh / cm². 2exhibited a uniform coulombic efficiency without prior cell short circuits and under the capacity condition of 1 mAh / cm² 2 The system operated stably for at least approximately 250 cycles without cell short circuits. This result contrasts with the results of the comparison example, where cell short circuits occur regardless of the capacity state (Comparison Example 1) without the lithium-friendly metal layer. Accordingly, it can be concluded that the lithium-friendly metal layer, as disclosed herein, offers improved initial efficiency characteristics and that charging / discharging is performed stably even under conditions of higher capacity.

[0073] Furthermore, in the Fig. 4A and Fig. 4B, it was found that the electrode used in the anode according to an embodiment of the present disclosure was stabilized under overvoltage, and thus a stable interface was formed, resulting in higher driving stability. In contrast, an electrode with the anode according to Comparative Example 1 exhibited an overvoltage that increased with each cycle repetition, and a side reaction occurred at an electrode interface due to the deposited lithium, which was subject to lower driving stability. Accordingly, the overvoltage was also improved under the overcharge condition to ensure driving stability in an anode according to the present disclosure.

[0074] Furthermore, a half-cell was formed using the anode for the solid-state battery produced in the embodiment of the present disclosure and in Comparative Example 2, and the electrochemical characteristics of the half-cell were evaluated. In this case, the half-cell was formed using the anode for the solid-state battery produced in the embodiment of the present disclosure and in Comparative Example 2, LPSCI, and lithium metal, and the charge / discharge conditions were set to a range of 0 V to 0.1 V. This experiment was carried out at a temperature of 25°C, a pressure of 20 MPa, an anode active material loading of 0.56 mg / cm², and a current density of 1.0 mA / cm² for evaluation. 2 held and the charging capacity set to 1 mA / cm² 2The coulombic efficiency was then measured as a function of a charge / discharge cycle using the anode according to one embodiment and comparative example 2, and presented in the form of a diagram. Fig. 3B is shown.

[0075] Fig. Figure 3B shows that the electrode used in the anode according to an embodiment of the present disclosure operates stably without cell short-circuiting even after more than 250 cycles, whereas Comparative Example 2, using an anode active material without Si, showed an earlier internal cell short-circuiting. Accordingly, it can be seen that the anode according to the present disclosure contains the anode active material layer with the Si-based anode active material and provides a cell that operates stably even after repeated cycles without cell short-circuiting. Experimental example 3: Evaluation of the electrochemical characteristics for a full cell

[0076] In this experiment, the electrochemical characteristics of a full cell were evaluated using the solid-state battery produced in Experimental Example 1 and by controlling the charge / discharge voltage conditions from 2.5 V to 4.2 V. Furthermore, this experiment was conducted at a temperature of 25°C, a pressure of 20 MPa, and an active material loading of 0.8 mg / cm³. 2 The test was carried out and a current density for evaluation was determined at 0.2 C (0.716 mA / cm²). 2 ). Subsequently, a voltage and capacity characteristic was recorded in an initial cycle, a voltage and capacity characteristic with progressive cycles, and a capacity maintenance rate as a function of a cycle number in Fig. 5A, Fig. 5B and Fig. 5C shown in the form of diagrams.

[0077] As in the Fig. 5A, Fig. 5B and Fig.As can be seen in Figure 5C, a cell using the anode according to an embodiment of the present disclosure exhibited an initial efficiency that was improved compared to a cell using the anode according to Comparative Example 1. Furthermore, a stable voltage profile, a higher capacity retention rate, and a higher coulombic efficiency were observed for the cell according to the embodiment shown, even when the cycles are repeated. Accordingly, the electrode using the anode according to the present disclosure can exhibit excellent initial efficiency, maintain a higher capacity and higher efficiency stably even when the cycles continue, and exhibit excellent electrochemical properties.

[0078] According to the present disclosure, the anode for the solid-state battery comprises a structure in which the anode active material layer is stacked on the lithium-friendly metal layer. The lithium-friendly metal layer can cause the lithium to be deposited beneath the anode active material layer, and the deposited lithium metal can act as a barrier to prevent direct reaction with the solid electrolyte. The anode active material layer contains the silicon-based complex as the anode active material, which promotes the diffusion of the lithium ion, thus facilitating lithium deposition. Accordingly, the anode, as described in the present disclosure, operates stably without cell short-circuiting under higher capacity conditions, since lithium deposition is stably induced without the growth of lithium dendrites, even when overcharging occurs beyond a theoretical capacity.Furthermore, the anode can stabilize the overvoltage and thus exhibit higher operational stability.

[0079] While certain features of the present disclosure have been described with reference to exemplary embodiments and the accompanying drawings, the present disclosure is not limited thereto, but can be modified and altered in various ways by those skilled in the art who are knowledgeable in the field of the present disclosure without departing from the spirit and scope of the present disclosure claimed in the following claims.

Claims

[1] Anode for a solid-state battery, the anode comprising: an anode current collector; a lithium-friendly metal layer stacked on the anode current collector; and an anode active material layer stacked on top of the lithium-friendly metal layer, wherein the anode active material layer contains a silicon-based anode active material. [2] Anode according to claim 1, wherein the anode active material is Si-based and has a theoretical electrochemical capacity of at least 100 mAh / g. [3] Anode according to claim 1, wherein the Si-based anode active material comprises a complex of Si or an active material selected from the group consisting of Si and graphite, lithium titanate (LTO), graphene, silicon-based oxide (SiOx) and a metal oxide. [4] Anode according to claim 1, wherein the anode active material is Si-based and is a Si-graphite complex. [5] Anode according to claim 1, wherein the anode active material layer further comprises a binder. [6] Anode according to claim 1, wherein the anode active material layer has an active material loading of 0.2 mg / cm² 2 up to 1.8 mg / cm² 2 includes. [7] Anode according to claim 1, wherein the anode active material layer further comprises a solid electrolyte. [8] Anode according to claim 1, wherein the lithium-friendly metal layer contains: at least one metal selected from the group consisting of Mg, Ag, Zn, Au, Ni, Co, Mn, Al, Cd and Ti. [9] Anode according to claim 1, wherein the lithium-friendly metal layer contains Mg. [10] Anode according to claim 1, wherein the lithium-friendly metal layer has a thickness of 10 nm to 5,000 nm. [11] Anode according to claim 1, wherein the anode is configured to deposit lithium under an alloy of the lithium-friendly metal layer and lithium when operated in an overloaded state. [12] Method for manufacturing an anode for a solid-state battery, the method comprising: Deposition of a lithium-friendly metal layer on an anode current collector (S1); Preparation of an anode active material slurry containing Si (S2); and Forming an anode active material layer by applying the anode active material slurry to the lithium-friendly metal layer and drying the slurry to provide the anode (S3). [13] Method according to claim 12, wherein the deposition of the lithium-friendly metal layer is carried out by physical vapor deposition. [14] Method according to claim 12, wherein the anode active material slurry has a viscosity of 100 cP to 200 cP. [15] Method according to claim 12, wherein the drying is carried out at a temperature of 70°C to 120°C. [16] Solid-state battery comprising the anode according to claim 1.

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