Negative electrode for all-solid-state battery and all-solid-state battery including negative electrode

Abstract

The invention relates to a negative electrode for an all-solid-state battery and an all-solid-state battery including the same. The negative electrode for an all-solid-state battery includes a current collector and a negative electrode catalyst layer on the current collector and including an amorphous carbon metal and clay.

Description

Technical Field

[0001] The invention discloses a negative electrode for an all-solid-state battery and an all-solid-state battery comprising the negative electrode. Background Art

[0002] Recently, the rapid replenishment of electronic devices (such as mobile phones, laptop computers) and electric vehicles using batteries has increased dramatically the demand for rechargeable batteries with relatively high capacity and light weight. In particular, rechargeable lithium batteries have recently attracted attention as driving power sources for portable devices because they have lighter weight and high energy density. Accordingly, research and development to improve the performance of rechargeable lithium batteries are being actively carried out.

[0003] All-solid-state batteries in rechargeable lithium batteries refer to batteries in which all materials are solid, especially batteries using solid electrolytes. One way to increase the energy density of these all-solid-state batteries is to use lithium metal as the negative electrode, however, in this case, there are problems due to lithium volume expansion and irreversible dendrite growth during charging and discharging.

[0004] In order to solve these problems, a method of configuring a negative electrode by forming a layer in which lithium is deposited on a negative electrode current collector during charge and discharge without using lithium metal itself is being studied. However, this method is inappropriate because it leads to low power characteristics and excessive occurrence of short circuit phenomena. Summary of the invention

[0005] Technical issues

[0006] Embodiments provide a negative electrode for an all-solid-state battery exhibiting excellent electrochemical characteristics.

[0007] Another embodiment provides an all-solid-state battery including a negative electrode.

[0008] Technical issues

[0009] Embodiments provide a negative electrode for an all-solid-state battery, including: a current collector; and a negative electrode catalyst layer located on the current collector and including amorphous carbon, metal, and clay.

[0010] The amount of the clay may be 1 wt% to 30 wt% or 10 wt% to 25 wt% based on 100 wt% of the total negative electrode catalyst layer.

[0011] The clay may be montmorillonite (MMT), halloysite, bentonite, kaolinite, saponite, surface-modified clay, pyrophyllite-talc, fluorohectorite, vermiculite, illite, mica, brittle mica, or a combination thereof.

[0012] The metal may be Ag, Au, Sn, Zn, Al, Mg, Ge, Cu, In, Ni, Bi, Pt, Pd, or a combination thereof.

[0013] The amorphous carbon may be carbon black, acetylene black, superconducting acetylene black, Ketjen black, furnace black, activated carbon or a combination thereof. The amorphous carbon may be carbon black, acetylene black, superconducting acetylene black, Ketjen black or a combination thereof.

[0014] The BET surface area of ​​clay can be 5m 2 / g~500m 2 / g.

[0015] The amount of the above metal may be 1 wt % to 50 wt % based on 100 wt % of the total weight of the negative electrode catalyst layer.

[0016] The amount of the amorphous carbon may be 20 wt % to 98 wt % based on 100 wt % of the total weight of the negative electrode catalyst layer.

[0017] Another embodiment provides an all-solid-state battery including: a negative electrode; a positive electrode; and a solid electrolyte layer between the negative electrode and the positive electrode.

[0018] The negative electrode may further include a lithium-containing layer between the current collector and the negative electrode catalyst layer.

[0019] Beneficial Effects

[0020] The negative electrode for an all-solid-state battery according to an embodiment may exhibit excellent electrochemical characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic diagram of an all-solid-state battery according to an embodiment.

[0022] Figure 2 Schematic diagram H of an all-solid-state battery according to another embodiment.

[0023] Figure 3 is a cross-sectional FE-SEM photograph of the negative electrode manufactured according to Example 1.

[0024] Figure 4 1 and 2 are photographs and graphs showing EDAX results of the negative electrode manufactured according to Example 1.

[0025] Figure 5 2 are photographs and graphs showing EDAX results of the negative electrode manufactured according to Comparative Example 1.

[0026] Figure 6 Graphs showing overvoltage results of all-solid-state half-cells manufactured according to Example 3 and Example 4 and Comparative Example 2 and Comparative Example 3.

[0027] Figure 7 This is a graph showing the discharge characteristics of the second cycle in Examples 1 to 5.

[0028] Figure 8 It is a graph showing the charging characteristics of the second cycle in Examples 1 to 5. DETAILED DESCRIPTION

[0029] Hereinafter, embodiments of the present invention will be described in detail. However, these embodiments are only examples, and the present invention is not limited thereto, and the present invention is defined by the scope of the claims.

[0030] The terms used herein are for describing the embodiments only and are not intended to limit the present disclosure. Expressions in the singular include plural expressions unless the context clearly indicates otherwise.

[0031] As used herein, "combinations thereof" means mixtures, laminates, composites, copolymers, alloys, blends, reaction products, and the like, of the components.

[0032] Here, the terms "comprise", "include" or "have" are intended to indicate the presence of a certain characteristic, quantity, step, constituent element or combination thereof, but it should be understood that the possibility of the presence or addition of one or more other characteristics, quantities, steps, constituent elements or combinations is not precluded.

[0033] To clearly illustrate the layers and regions, the drawings show exaggerated thickness, and like reference numerals denote similar components throughout the specification. It will be understood that when an element (such as a layer, film, region, or substrate) is referred to as being "on" another element, it can be directly on the other element, or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements.

[0034] In addition, the “layer” herein includes not only a shape formed on the entire surface but also a shape formed on a part of the surface when viewed from a plan view.

[0035] In this document, “or” is not interpreted as being exclusive. For example, “A or B” is interpreted as including A, B, and A+B, etc.

[0036] Unless otherwise specified in this specification, the particle size or size may be an average particle size. The average particle diameter refers to the average particle size (D 50 ), which means the diameter of particles with a cumulative volume of 50% by volume in the particle size distribution. Average particle size (D 50) can be measured by methods well known to those skilled in the art (e.g., by measuring with a particle size analyzer, by a transmission electron microscope or a scanning electron microscope). Alternatively, a dynamic light scattering measurement device is used to perform data analysis, and the number of particles in each particle size range is counted, and thus, the average particle diameter (D) can be easily obtained by calculation. 50 )value.

[0037] A negative electrode for an all-solid-state battery according to an embodiment includes: a current collector; and a negative electrode catalyst layer located on the current collector and including amorphous carbon, metal, and clay.

[0038] In an embodiment, the negative electrode catalyst layer refers to a layer that helps lithium ions extracted from the positive electrode active material move toward the negative electrode and precipitate on the surface of the current collector during charging and discharging of the all-solid-state battery. That is, due to the precipitation of lithium ions, a lithium deposition layer is formed between the current collector and the negative electrode catalyst layer, and the lithium deposition layer acts as a negative electrode active material, and this negative electrode is generally referred to as a precipitation-type negative electrode.

[0039] If the negative electrode catalyst layer including amorphous carbon and metal includes clay, the clay can improve the mobility of lithium ions and form a stable path, thereby ensuring the formation of a uniform lithium layer and inhibiting the formation of lithium dendrites. In general, if the all-solid-state battery is charged and discharged, an overvoltage may occur at the negative electrode, which may cause excessive lithium dendrites to form on the surface of the negative electrode, and these dendrites may penetrate the electrolyte and contact the positive electrode, which may lead to a problem of reduced cycle life, however, the negative electrode according to the embodiment can effectively prevent this problem. In addition, if the negative electrode catalyst layer includes clay, the charging efficiency / discharging efficiency can be improved.

[0040] In an embodiment, the amount of clay may be 1 wt% to 30 wt%, 5 wt% to 30 wt%, or 10 wt% to 25 wt% based on 100 wt% of the total negative electrode catalyst layer. At this time, if the amount of clay is within the above range, the lithium dendrite prevention effect and the charge / discharge improvement effect can be more effectively obtained due to the use of clay.

[0041] The clay may be montmorillonite (MMT), halloysite, bentonite, kaolinite, saponite, surface-modified clay, pyrophylite-talc, fluorohectorite, vermiculite, illite, mica, brittle mica, or a combination thereof. The surface-modified clay may be any surface-modified clay known in the art, such as clay whose surface is modified by plasma treatment, clay having hydroxyl groups bonded to the surface, clay modified with a quaternary ammonium salt, and the like.

[0042] The BET surface area of ​​clay can be 5m 2 / g~500m 2 / g, 25m 2 / g~300m 2 / g or 50m 2 / g~250m 2 / g. If the specific surface area of ​​the clay is within the above range, the clay can function more appropriately, thereby forming a uniform lithium. If the specific surface area of ​​the clay is less than 5m 2 / g, the surface area that interacts with lithium ions is small, so clay cannot play its role well, and if the specific surface area of ​​clay is greater than 500m 2 / g, if a negative electrode slurry is produced, the specific surface area is too high, resulting in uneven slurry and a surface area path for lithium ions may become long, which may slightly increase the overvoltage.

[0043] If clay is used in a negative electrode catalyst layer containing both amorphous carbon and metal, the effect of including such clay can be obtained. If clay is used in a negative electrode catalyst layer including only amorphous carbon, it is inappropriate because short circuits occur during charge and discharge.

[0044] In an embodiment, the metal included in the negative electrode catalyst layer may be Ag, Au, Sn, Zn, Al, Mg, Ge, Cu, In, Ni, Bi, Pt, Pd, or a combination thereof. In an embodiment, the metal may be Ag. Since the negative electrode catalyst layer includes metal and clay, the electrical conductivity of the negative electrode may be further improved without causing a short circuit during charge and discharge.

[0045] The metal may be a nanoparticle, and the size of the metal nanoparticle may be, for example, an average size of 5 nm to 80 nm, but the nanosize may be appropriate. By using metal nanoparticles having such a nanosize, the battery characteristics (e.g., cycle life characteristics) of the all-solid-state battery may be further improved. If the metal particle size is increased to the micron level, the uniformity of the metal particles in the negative electrode catalyst layer is reduced, which is inappropriate because the current density in a specific area increases and the cycle life characteristics may deteriorate.

[0046] The amorphous carbon may be carbon black, acetylene black, superconducting acetylene black, Ketjen black, furnace black, activated carbon, or a combination thereof. An example of carbon black is Super P (Timcal). The amorphous carbon may be carbon black, acetylene black, superconducting acetylene black, Ketjen black, or a combination thereof.

[0047] In the negative electrode catalyst layer according to an embodiment, the amount of the metal may be 1 wt% to 50 wt%, 3 wt% to 30 wt%, 4 wt% to 25 wt%, 5 wt% to 20 wt%, or 5 wt% to 15 wt% based on 100 wt% of the weight of the negative electrode catalyst layer.

[0048] In addition, the carbon-based material may be present in an amount of 20 wt% to 98 wt%, 40 wt% to 95 wt%, 60 wt% to 95 wt%, 80 wt% to 95 wt%, or 85 wt% to 95 wt%, based on 100 wt% of the total weight of the negative electrode catalyst layer.

[0049] If the amount of metal or carbon material is within the above range, the metal can be uniformly dispersed in the carbon material. In addition, if the amount of metal and carbon material is within the above range, the lithium ions extracted from the positive electrode active material during charging move toward the negative electrode, and the lithium precipitation layer is basically formed between the current collector and the negative electrode layer, so if lithium precipitation occurs on the surface of the negative electrode layer, problems (such as short circuit problems, problems caused by side reactions with electrolytes, or problems of cracks on the negative electrode side) can be effectively suppressed.

[0050] In addition, the amorphous carbon may be a single particle or an aggregate having secondary particles in which primary particles are aggregated. If the amorphous carbon is a single particle, it may be an amorphous carbon particle having an average particle size of less than or equal to 100 nm (eg, a nanometer size of 10 nm to 100 nm).

[0051] In addition, if the amorphous carbon is an aggregate, the particle size of the primary particles may be 20 nm to 100 nm, and the particle size of the secondary particles may be 1 μm to 20 μm.

[0052] In an embodiment, the particle size of the primary particles may be greater than or equal to 20nm, greater than or equal to 30nm, greater than or equal to 40nm, greater than or equal to 50nm, greater than or equal to 60nm, greater than or equal to 70nm, greater than or equal to 80nm, or greater than or equal to 90nm, and less than or equal to 100nm, less than or equal to 90nm, less than or equal to 80nm, less than or equal to 70nm, less than or equal to 60nm, less than or equal to 50nm, less than or equal to 40nm, or less than or equal to 30nm.

[0053] In an embodiment, the particle size of the secondary particles may be greater than or equal to 1 μm, greater than or equal to 3 μm, greater than or equal to 5 μm, greater than or equal to 7 μm, greater than or equal to 10 μm, or greater than or equal to 15 μm, and less than or equal to 20 μm, less than or equal to 15 μm, less than or equal to 10 μm, less than or equal to 7 μm, less than or equal to 5 μm, or less than or equal to 3 μm.

[0054] The shape of the primary particle may be spherical, ellipsoidal, plate-like, and combinations thereof, and in an embodiment, the shape of the primary particle may be spherical, ellipsoidal, and combinations thereof.

[0055] The negative electrode catalyst layer may further include a binder.

[0056] The binder may include a non-aqueous binder, an aqueous binder, or a combination thereof.

[0057] The non-aqueous binder may include, for example, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide-containing polymers, ethylene propylene copolymers, polystyrene, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamideimide, polyimide, polyacrylate, or a combination thereof.

[0058] The water-based binder may include a rubber-based binder or a polymer resin binder. The rubber binder may be selected from styrene-butadiene rubber, acrylated styrene-butadiene rubber, acrylonitrile-butadiene rubber, acrylic rubber, butyl rubber, fluororubber and combinations thereof. The polymer resin binder may be selected from polyethylene oxide, polyvinyl pyrrolidone, polyepichlorohydrin, polyphosphazene, polyacrylonitrile, ethylene propylene diene copolymer, polyvinyl pyridine, chlorosulfonated polyethylene, latex, polyester resin, acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol and combinations thereof.

[0059] If an aqueous binder is used as a negative electrode binder, a thickener capable of imparting viscosity may be used together, and the thickener may include, for example, a cellulose compound. The cellulose compound may include carboxymethyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose, an alkali metal salt thereof, or a combination thereof. The alkali metal may be Na, K, or Li. Based on 100 parts by weight of the negative electrode active material, the amount of such a thickener used may be 0.1 parts by weight to 3 parts by weight. The cellulose compound may also serve as a binder.

[0060] The binder is not limited thereto, and any binder used in the related art may be used, and the amount of the binder may also be appropriately adjusted.

[0061] The binder may be included in an amount of 1 wt % to 15 wt % based on 100 wt % of the total negative electrode catalyst layer, and for example, may be included in an amount of greater than or equal to 1 wt %, greater than or equal to 2 wt %, greater than or equal to 3 wt %, greater than or equal to 4 wt %, greater than or equal to 5 wt %, greater than or equal to 6 wt %, greater than or equal to 7 wt %, greater than or equal to 8 wt %, greater than or equal to 9 wt %, greater than or equal to 10 wt %, greater than or equal to 11 wt %, greater than or equal to 12 wt %, greater than or equal to 14 wt %, greater than or equal to 15 wt %, greater than or equal to 16 wt %, greater than or equal to 17 wt %, greater than or equal to 18 wt %, greater than or equal to 19 wt %, greater than or equal to 20 wt %, greater than or equal to 21 wt %, greater than or equal to 23 wt %, greater than or equal to 24 wt %, greater than or equal to 25 wt %, greater than or equal to 26 wt %, greater than or equal to 27 wt %, greater than or equal to 28 wt %, greater than or equal to 29 wt %, greater than or equal to 30 wt %, greater than or equal to 31 wt %, greater than or equal to 32 wt %, greater than or equal to 33 wt %, greater than or equal to 34 wt %, greater than or equal to 35 wt %, greater than or equal to 36 wt %, greater than or equal to 37 wt %, greater than or equal to 38 wt %, greater than or equal to 39 wt %, greater than or equal to 40 wt %, greater than or equal to 41 wt The amount of 12wt%, greater than or equal to 13wt% or greater than or equal to 14wt% and less than or equal to 15wt%, less than or equal to 14wt%, less than or equal to 13wt%, less than or equal to 12wt%, less than or equal to 11wt%, less than or equal to 10wt%, less than or equal to 9wt%, less than or equal to 8wt%, less than or equal to 7wt%, less than or equal to 6wt%, less than or equal to 5wt%, less than or equal to 4wt%, less than or equal to 3wt% or less than or equal to 2wt% includes the binder.

[0062] If the binder is included in the negative electrode catalyst layer of the all-solid-state battery in the above amount range, resistance and adhesive strength may be improved, thereby improving the characteristics of the all-solid-state battery (battery capacity and power characteristics).

[0063] The negative electrode catalyst layer may further include additives such as fillers, dispersants, or ion conductive materials. The fillers, dispersants, ion conductive materials, etc. that may be included in the negative electrode catalyst layer may be known materials generally used for all-solid-state batteries.

[0064] According to an embodiment, the negative electrode may further include a lithium-containing layer between the current collector and the negative electrode catalyst layer.

[0065] Since the above-mentioned lithium-containing layer is a metal layer including lithium, it can function as a lithium storage layer.

[0066] The lithium-containing layer may be a lithium precipitation layer in which lithium ions extracted from the positive electrode active material during charging move toward the negative electrode and are precipitated on the surface of the current collector. In this case, the lithium-containing layer may be referred to as a lithium precipitation layer.

[0067] The lithium-containing layer may be a layer including lithium or a lithium alloy.

[0068] The lithium alloy includes lithium and may also include a metal capable of forming an alloy with lithium. The metal capable of forming an alloy with lithium may be Ag, Au, Mg, In, Si, Sn, Al, Ge, Pb, Bi, Sb, Si-Y alloy (wherein Y is an alkali metal, an alkaline earth metal, a Group 13 element, a Group 14 element, a transition metal, a rare earth element, or a combination thereof, but not Si), Sn-Y alloy (wherein Y is an alkali metal, an alkaline earth metal, a Group 13 element, a Group 14 element, a transition metal, a rare earth element, or a combination thereof, but not Sn), etc. The element Y may be Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Ti, Ge, P, As, Sb, Bi, S, Se, Te, Po or a combination thereof.

[0069] The thickness of the lithium-containing layer may be 1 μm to 1000 μm, 1 μm to 500 μm, 1 μm to 200 μm, 1 μm to 150 μm, 1 μm to 100 μm, or 1 μm to 50 μm. If the thickness of the lithium-containing layer is within the above range, it can be appropriately used as a lithium storage layer and its cycle life can be further improved.

[0070] If the lithium-containing layer is a lithium precipitation layer, the lithium precipitation layer may be formed if, during charging after manufacturing an all-solid-state battery, lithium ions are deintercalated from the positive electrode active material, pass through the solid electrolyte, and move toward the negative electrode, causing lithium to precipitate and precipitate on the negative electrode current collector.

[0071] The charging process may be a forming process performed 1 to 3 times at 0.05C to 1C at about 25° C. to 50° C. Since lithium included in the lithium-containing layer is ionized and moves toward the positive electrode during discharge, lithium may be used as a negative electrode active material.

[0072] In an embodiment, since the lithium-containing layer exists between the current collector and the negative electrode active material layer, the negative electrode catalyst layer can be used as a protective layer for the lithium-containing layer, thereby suppressing the precipitation growth of lithium dendrites. As a result, short circuit and capacity reduction of the all-solid-state battery can be suppressed, and as a result, the cycle life of the all-solid-state battery can be improved.

[0073] The current collector may include, for example, indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li) or an alloy thereof, and may be in the form of a foil or sheet. The thickness of the negative electrode current collector may be 1 μm to 20 μm, 5 μm to 15 μm or 7 μm to 10 μm.

[0074] The current collector may include a metal substrate, and may further include a thin film formed on the substrate. The thin film may include an element that can form an alloy with lithium, and may be, for example, gold, silver, zinc, tin, indium, silicon, aluminum, bismuth, or a combination thereof, but is not limited thereto, and in the technical field, any element that can form an alloy with lithium may be used. If the current collector further includes a thin film, and a lithium-containing layer is formed by precipitation during charging, a more planarized lithium-containing layer may be formed, thereby further improving the cycle life of the all-solid-state battery.

[0075] The thickness of the thin film may be 1 nm to 800 nm, 10 nm to 700 nm, 50 nm to 600 nm, or 100 nm to 500 nm. If the thickness of the thin film is within the above range, the cycle life characteristics may be further improved.

[0076] Another embodiment provides an all-solid-state battery including a negative electrode, a positive electrode, and a solid electrolyte layer between the negative electrode and the positive electrode.

[0077] The solid electrolyte in the solid electrolyte layer 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.

[0078] In an embodiment, the sulfide-based solid electrolyte may be, for example, Li 2 SP 2 S 5 , Li 2 SP 2 S 5 -LiX (wherein X is a halogen element, such as I or Cl), Li 2 SP 2 S 5 -Li 2 O. Li 2 SP 2 S 5 -Li 2 O-LiI、Li 2 S-SiS 2 , Li 2 S-SiS 2 -LiI, Li 2 S-SiS 2 -LiBr, Li 2S-SiS 2 -LiCl, Li 2 S-SiS 2 -B 2 S 3 -LiI, Li 2 S-SiS 2 -P 2 S 5 -LiI, Li 2 SB 2 S 3 , Li 2 SP 2 S5-Z m S n (wherein m and n are integers of 0 or more and 12 or less, and Z is one of Ge, Zn or Ga), Li 2 S-GeS 2 , Li 2 S-SiS 2 -Li 3 PO 4 , Li 2 S-SiS 2 -Li p MO q (wherein p and q are each 0 or more and 12 or less, and M is one of P, Si, Ge, B, Al, Ga, or In) or Li a M b P c S d A e (wherein a, b, c, d and e are each 0 or greater and 12 or less, M is Ge, Sn, Si or a combination thereof, and A is one of F, Cl, Br or I). For example, it may be, for example, Li 7- x PS 6-x F x (0≤x≤2), Li 7-x PS 6-x Cl x (0≤x≤2), Li 7-x PS 6-x Br x (0≤x≤2) or Li 7-x PS 6-x I x (0≤x≤2). In addition, specifically, it may be Li 3 PS 4 , Li 7 P 3 S 11 , Li 7 PS 6 , Li6 PS 5 Cl, Li 6 PS 5 Cl, Li 6 PS 5 I. Li 6 PS 5 Br, Li 5.8 PS 4.8 Cl 1.2 , Li 6.2 PS 5.2 Br 0.8 wait.

[0079] For example, the sulfide solid electrolyte may be an argyrodite-type sulfide solid electrolyte. The sulfide solid electrolyte may be, for example, Li a M b P c S d A e (wherein a, b, c, d and e are all 0 or more and 12 or less, M is Ge, Sn, Si or a combination thereof, and A is F, Cl, Br or I), and specifically Li 3 PS 4 , Li 7 P 3 S 11 , Li 7 PS 6 , Li 6 PS 5 Cl, Li 6 PS 5 Br, Li 6 PS 5 I. Li 5.8 PS 4.8 Cl 1.2 , Li 6.2 PS 5.2 Br 0.8 wait.

[0080] The sulfide-based solid electrolyte may be amorphous, crystalline, or a mixed state thereof. The sulfide-based solid electrolyte may be prepared by mixing Li and Mg in a molar ratio of 50:50 to 90:10 or 50:50 to 80:20. 2 S and P 2 S 5 In the above-mentioned mixing ratio range, a sulfide-based solid electrolyte having excellent ion conductivity can be prepared. 2 ,GeS 2 , B 2 S 3As other components, the ionic conductivity is further improved. Mechanical grinding or solution method can be applied as a mixing method. Mechanical grinding is to make the raw materials into microparticles by placing the raw materials, grinding balls (ball mills), etc. into a reactor and stirring them vigorously. The solution method can be carried out by mixing the raw materials in a solvent to obtain a solid electrolyte as a precipitate. In addition, additional firing can be performed after mixing. If additional firing is performed, the crystals of the solid electrolyte will become harder.

[0081] Of course, a commercially available solid electrolyte can be used as the sulfide-based solid electrolyte.

[0082] The oxide-based solid electrolyte may be, for example, Li 1+x Ti 2-x Al(PO 4 ) 3 (LTAP)(0≤x≤4), Li 1+x+y Al x Ti 2- x Si y P 3-y O 12 (0 <x<2,0≤y<3)、BaTiO 3 、Pb(Zr,Ti)O 3 (PZT), Pb 1-x La x Zr 1-y Ti y O 3 (PLZT)(0≤x<1, 0≤y<1), Pb(Mg 3 Nb 2 / 3 ) 3 -PbTiO 3 (PMN-PT), HfO 2 、SrTiO 3 SnO 2 、CeO 2 、Na 2 O, MgO, NiO, CaO, BaO, ZnO, ZrO 2 , Y 2 O 3 、Al 2 O 3 、TiO 2 、SiO 2 、Lithium phosphate (Li 3 PO 4 ), lithium titanium phosphate (Li x Ti y (PO 4 ) 3 , 0 <x<2,0<y<3)、Li1+x+y (Al, Ga) x (Ti, Ge) 2-x Si y P 3-y O 12 (0 ≤ x ≤ 1, and 0 ≤ y ≤ 1), lanthanum lithium titanate (Li x La y TiO 3 , 0 < x < 2, and 0 < y < 3), Li 2 O, LiAlO 2 、Li 2 O - Al 2 O 3 - SiO 2 - P 2 O 5 - TiO 2 - GeO 2 - type ceramics, garnet - type ceramics Li 3+ x La 3 M 2 O 12 (M = Te, Nb or Zr, and x is an integer from 1 to 10) or a mixture thereof.

[0083] The solid polymer electrolyte may include, for example, those selected from polyethylene oxide, poly(diallyldimethylammonium) trifluoromethanesulfonimide (poly(diallyldimethylammonium) TFSI), Cu 3 N, Li 3 N, LiPON, Li 3 PO 4 ·Li 2 S·SiS 2 、Li 2 S·GeS 2 ·Ga 2 S 3 、Li 2 O·11Al 2 O 3 、Na 2 O·11Al 2 O 3 、(Na, Li) 1+x Ti 2-x Al x (PO 4 ) 3 (0.1 ≤ x ≤ 0.9), Li 1+x Hf 2-x Al x (PO 4 ) 3 (0.1 ≤ x ≤ 0.9), Na 3 Zr2 Si 2 PO 12 、Li 3 Zr 2 Si 2 PO 12 、Na 5 ZrP 3 O 12 、Na 5 TiP 3 O 12 、Na 3 Fe 2 P 3 O 12 、Na 4 NbP 3 O 12 、 sodium silicate, Li 0.3 La 0.5 TiO 3 、Na 5 MSi 4 O 12 (where M is a rare earth element such as Nd, Gd, Dy, etc.), Li 5 ZrP 3 O 12 、Li 5 TiP 3 O 12 、Li 3 Fe 2 P 3 O 12 、Li 4 NbP 3 O 12 、Li 1+x (M, Al, Ga) x (Ge 1-y Ti y ) 2-x (PO 4 ) 3 (x ≤ 0.8, 0 ≤ y ≤ 1.0, and 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 (0 < x ≤ 0.4, 0 < y ≤ 0.6, and Q is Al or Ga), Li 6 BaLa 2 Ta 2 O 12 、Li 7 La 3 Zr 2 O12 、 Li 5 La 3 Nb 2 O 12 、 Li 5 La 3 M 2 O 12 (where M is Nb or Ta) and Li 7+x A x La 3-x Zr 2 O 12 (0 < x < 3, and A is Zn) or more of them.

[0084] The halide solid electrolyte may include Li element, M element (M is a metal other than Li) and X element (X is a halogen). Examples of X may include F, Cl, Br and I. In particular, in the halide solid electrolyte, at least one of Br and Cl is suitable as the above X. In addition, examples of M may include metal elements (such as Sc, Y, B, Al, Ga and In).

[0085] The composition of the halide solid electrolyte is not particularly limited, but may be represented by Li 6-3a M a Br b Cl c (where M is a metal other than Li, 0 < a < 2, 0 ≤ b ≤ 6, 0 ≤ c ≤ 6, b + c = 6). At this time, a may be 0.75 or more, 1 or more, and a may be 1.5 or less. b may be 1 or more, and may be 2 or more. In addition, c may be 3 or more, and may be 4 or more. Specific examples of the halide solid electrolyte may be Li 3 YBr 6 、 Li 3 YCl 6 or Li 3 YBr 2 Cl 4 .

[0086] The solid electrolyte may be in the form of particles, and the average particle size (D 50 ) may be less than or equal to 5.0 μm, for example, 0.1 μm to 5.0 μm, 0.5 μm to 5.0 μm, 0.5 μm to 4.0 μm, 0.5 μm to 3.0 μm, 0.5 μm to 2.0 μm or 0.5 μm to 1.0 μm.

[0087] The solid electrolyte layer may further include a binder. At this time, the binder may be styrene butadiene rubber, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, an acrylic polymer or a combination thereof, but is not limited thereto, and any substance used as a binder in the art may be used. The acrylic polymer may be butyl acrylate, polyacrylate, polymethacrylate or a combination thereof.

[0088] The solid electrolyte layer can be formed by adding a solid electrolyte to a binder solution, coating it on a base film, and drying the resultant. The solvent of the binder solution may be isobutyl isobutyrate, xylene, toluene, benzene, hexane, or a combination thereof. The formation process of the solid electrolyte layer is well known in the art, so a detailed description thereof will be omitted.

[0089] The positive electrode includes a positive electrode current collector and a positive electrode active material layer on one surface of the positive electrode current collector. The positive electrode active material layer may include a positive electrode active material. The positive electrode active material may be a lithiated compound capable of reversibly inserting and extracting lithium ions, or the positive electrode active material may be a sulfur compound.

[0090] The lithiated compound may be, for example, at least one of a composite oxide of lithium and a metal selected from cobalt, manganese, nickel, and a combination thereof. Examples of the lithiated compound may include Li a A 1-b B 1 b D 1 2 (0.90≤a≤1.8, 0≤b≤0.5); Li a E 1-b B 1 b O 2- c D 1 c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5); Li a E 2-b B 1 b O 4-c D 1 c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤05); Li a Ni 1-b-c Co b B 1 c D 1 α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α≤2); Li a Ni 1-b- cCo b B 1 c O 2-α F 1 α (0.90≤a≤1.8,0≤b≤0.5,0≤c≤0.5,0<α<2);Li a Ni 1-b-c Co b B 1 c O 2-α F 1 2 (0.90≤a≤1.8,0≤b≤0.5,0≤c≤0.5,0<α<2);Li a Ni 1-b-c Mr b B 1 c D 1 α (0.90≤a≤1.8,0≤b≤0.5,0≤c≤0.5,0<α≤2);Li a Ni 1-b-c Mr b B 1 c O 2-α F 1 α (0.90≤a≤1.8,0≤b≤0.5,0≤c≤0.5,0<α<2);Li a Ni 1-b-c Mr b B 1 c O 2-α F 1 2 (0.90≤a≤1.8,0≤b≤0.5,0≤c≤0.5,0<α<2);Li a Ni b HAVE BEEN c G d O 2 (0.90≤a≤1.8,0≤b≤0.9,0≤c≤0.5,0.001≤d≤0.1);Li a Ni b Co c L 1 d G e O 2 (0.90≤a≤1.8,0≤b≤0.9,0≤c≤0.5,0≤d≤0.5,0.001≤e≤0.1);Li a NiG b O 2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a CoG b O 2 (0.90≤a≤1.8, 0.001≤b≤0.1); Li a MnG b O 2 (0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 2 G b O 4 (0.90≤a≤1.8, 0.001≤b≤0.1); QO 2 ;QS 2 ;LiQS 2 ; V 2 O 5 ;LiV 2 O 5 ;LiI 1 O 2 ;LiNiVO 4 ;Li (3-f) J 2 (PO 4 ) 3 (0≤f≤2);Li (3-f) Fe 2 (PO 4 ) 3 (0≤f≤2); or LiFePO 4 .

[0091] In the above chemical formula, A is Ni, Co, Mn or a combination thereof; B 1 Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements or a combination thereof; D 1 is O, F, S, P or a combination thereof; E is Co, Mn or a combination thereof; F 1 is F, S, P or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V or a combination thereof; Q is Ti, Mo, Mn or a combination thereof; I 1 is Cr, V, Fe, Sc, Y or a combination thereof; J is V, Cr, Mn, Co, Ni, Cu or a combination thereof; and L 1 It is Mn, Al or a combination thereof.

[0092] According to an embodiment, the positive electrode active material may be a ternary lithium transition metal (such as LiNi x Co y Al z O 2 (NCA), LiNi x Coy Mn z O 2 (NCM)(where 0 <x<1,0<y<1,0<z<1,x+y+z=1))。

[0093] In addition, the compound may have a coating on the surface, or may be mixed with another compound having a coating. The coating may include at least one coating element compound selected from the oxide of the coating element, the hydroxide of the coating element, the oxyhydroxide of the coating element, the oxycarbonate of the coating element, and the hydroxycarbonate of the coating element. The compound for the coating may be amorphous or crystalline. The coating element included in the coating may include Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, or a mixture thereof. By using these elements in the compound, the coating can be set in a method that has no adverse effect on the characteristics of the positive electrode active material, for example, the method may include any coating method (such as spraying, dipping, etc.), but is not explained in more detail because it is well known in the relevant art.

[0094] In addition, as the coating layer, any known coating layer of a positive electrode active material for an all-solid-state battery may be applied, and examples thereof include Li 2 O-ZrO 2 (LZO).

[0095] In addition, if the positive electrode active material includes nickel, cobalt and manganese, or nickel, cobalt and aluminum, the capacity density of the all-solid-state battery can be further improved, and the metal dissolution of the positive electrode active material in the charged state can be further reduced. Thus, the long-term reliability and cycle characteristics of the all-solid-state battery can be further improved in the charged state.

[0096] Sulfur compounds can be elemental sulfur (S 8 ), solid Li 2 S n (n≥1), including dissolved Li 2 S n (n≥1) positive electrode electrolyte, organic sulfur compound, carbon sulfur polymer [(C 2 S x ) n , x=2.5~50, n≥2] or a combination thereof.

[0097] Here, examples of the shape of the positive electrode active material include particle shapes (such as spherical and ellipsoidal). In addition, the average particle size of the positive electrode active material is not particularly limited, and may be within the range of positive electrode active materials applicable to existing all-solid-state rechargeable batteries. In addition, the amount of the positive electrode active material in the positive electrode active material layer is not particularly limited, and may be within the range of positive electrode layers applicable to existing all-solid-state rechargeable batteries.

[0098] The positive electrode active material layer may further include a solid electrolyte. The solid electrolyte included in the positive electrode active material layer may be the aforementioned solid electrolyte, and in this case, it may be the same as or different from the solid electrolyte included in the solid electrolyte layer. The solid electrolyte may be included in an amount of 10 wt% to 30 wt% based on the total weight of the positive electrode active material layer.

[0099] The current collector may include, for example, indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li) or an alloy thereof, and may be in the form of a foil or sheet.

[0100] The positive electrode active material layer may further include a binder and / or a conductive material.

[0101] The binder may include polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide-containing polymers, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin, nylon, etc., but are not limited thereto.

[0102] The binder may be included in an amount of 0.1 wt % to 5 wt % or 0.1 wt % to 3 wt % based on the total weight of each component of the positive electrode for an all-solid-state battery, or based on the total weight of the positive electrode active material layer. Within the above amount range, the binder may fully exhibit binding ability without deteriorating battery performance.

[0103] Conductive materials are used to give the electrodes conductivity, and any material that does not cause chemical changes and conducts electrons can be used in the battery. Examples thereof may include: carbon-based materials (such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanotubes, etc.); metal-based materials including copper, nickel, aluminum, silver, etc. and in the form of metal powder or metal fiber; conductive polymers (such as polyphenylene derivatives); or in the form of a mixture thereof.

[0104] Based on the total weight of each component of the positive electrode for an all-solid-state battery, or based on the total weight of the positive electrode active material layer, the conductive material may be included in an amount of 0.1 wt% to 5 wt% or 0.1 wt% to 3 wt%. Within the above amount range, the conductive material may improve electrical conductivity without deteriorating battery performance.

[0105] The thickness of the positive electrode active material layer may be 90 μm to 200 μm. For example, the thickness of the positive electrode active material layer may be greater than or equal to 90 μm, greater than or equal to 100 μm, greater than or equal to 110 μm, greater than or equal to 120 μm, greater than or equal to 130 μm, greater than or equal to 140 μm, greater than or equal to 150 μm, greater than or equal to 160 μm, greater than or equal to 170 μm, greater than or equal to 180 μm, or greater than or equal to 190 μm, and less than or equal to 200 μm, less than or equal to 190 μm, less than or equal to 180 μm, less than or equal to 170 μm, less than or equal to 160 μm, less than or equal to 150 μm, less than or equal to 140 μm, less than or equal to 130 μm, less than or equal to 120 μm, or less than or equal to 110 μm. As described above, since the thickness of the positive electrode active material layer is thicker than that of the negative electrode active material layer, the capacity of the positive electrode is larger than that of the negative electrode.

[0106] The positive electrode may be manufactured by forming a positive electrode active material layer on a positive electrode current collector by dry coating or wet coating.

[0107] In an embodiment, a buffer material may be further included to buffer the thickness change that occurs when the all-solid-state battery is charged and discharged. The buffer material may be present between the negative electrode and the casing, and in the case of a battery in which one or more electrode assemblies are stacked, the buffer material may be present between different electrode assemblies.

[0108] The buffer material may include a material having an elastic recovery rate of 50% or more and may have an insulating function, and specifically includes silicone rubber, acrylic rubber, fluorine-based rubber, nylon, synthetic rubber, or a combination thereof. The buffer material may exist in the form of a polymer sheet.

[0109] Figure 1 is a cross-sectional view of an all-solid-state battery according to an embodiment. Figure 1 The all-solid-state battery 100 includes an electrode assembly and a housing (such as a bag) for accommodating the electrode assembly, in which a negative electrode 400 (including a negative electrode current collector 401 and a negative electrode catalyst layer 403), a solid electrolyte layer 300, and a positive electrode 200 (including a positive electrode active material layer 203 and a positive electrode current collector 201) are stacked. The all-solid-state battery 100 may further include an elastic layer 500 on the outside of at least one of the positive electrode 200 and the negative electrode 400. Although Figure 1 One electrode assembly including the negative electrode 400 , the solid electrolyte layer 300 , and the positive electrode 200 is shown, but an all-solid-state battery may also be manufactured by stacking two or more electrode assemblies.

[0110] Figure 2The structure of an all-solid-state battery in a charged state is schematically illustrated. The all-solid-state battery 100 includes a positive electrode 200 (including a positive electrode current collector 201 and a positive electrode active material layer 203), a negative electrode 400' (including a negative electrode current collector 401', a negative electrode catalyst layer 403'), a solid electrolyte layer 300 between the positive electrode 200 and the negative electrode 400', and a battery case 500 accommodating these.

[0111] In addition, lithium ions are deintercalated from the positive electrode active material and deposited on the negative electrode current collector 401 ′, and as a result, a lithium-containing layer 405 ′ is provided between the current collector 401 ′ and the negative electrode catalyst layer 403 ′.

[0112] The all-solid-state battery according to the embodiment may be manufactured by placing a negative electrode, a positive electrode, and a solid electrolyte layer between the negative electrode and the positive electrode, preparing a stack, and pressing the stack.

[0113] The pressing process may be performed in the range of 25°C to 90°C. In addition, the pressing process may be performed by pressing at a pressure of less than or equal to 550 MPa, such as less than or equal to 500 MPa, such as 1 MPa to 500 MPa. The pressing time may vary according to the temperature and pressure, and may be, for example, less than 30 minutes. The pressing process may be, for example, isostatic press, roll press, or plate press.

[0114] Example

[0115] Hereinafter, examples and comparative examples of the present invention are described. However, these examples should not be construed as limiting the scope of the present invention in any sense.

[0116] (Example 1)

[0117] (1) Fabrication of negative electrode

[0118] The carbon black was prepared by mixing 86.1 wt% carbon black, 4.6 wt% Ag with an average size of 60 nm, and 1.0 wt% montmorillonite (specific surface area: 250 m 2 / g), 2.8wt% of carboxymethyl cellulose and 5.5wt% of styrene-butadiene rubber to prepare a negative electrode catalyst layer slurry.

[0119] The prepared slurry was coated on a stainless steel foil current collector and then vacuum dried at 80° C. to fabricate a negative electrode including a 12 μm-thick negative electrode catalyst layer and a 10 μm-thick current collector.

[0120] (2) Fabrication of solid electrolyte layer

[0121] An isobutyl isobutyrate binder solution (solid content: 50 wt%) prepared by adding an acrylic acid ester polymer of butyl acrylate was added to the Li 6 PS 5 The solid electrolyte and the binder are mixed in a weight ratio of 98.7:1.3.

[0122] The mixing process was performed by using a Thinky mixer. Subsequently, 2 mm zirconia balls were added to the obtained mixture, and then stirred again by using a Thinky mixer to prepare a slurry. The slurry was cast on a polytetrafluoroethylene release film and then dried at room temperature to manufacture a 100 μm thick solid electrolyte layer.

[0123] (3) Manufacturing of all-solid-state half-battery cells

[0124] The fabricated negative electrode, solid electrolyte, and lithium metal counter electrode were sequentially stacked, and a pressure of 8 MPa was applied to fabricate an all-solid-state half-cell (torque half-cell).

[0125] (Example 2)

[0126] A negative electrode was manufactured in the same manner as in Example 1, except that 82.1 wt % of carbon black, 4.6 wt % of Ag having an average size of 60 nm, 5.0 wt % of montmorillonite, 2.8 wt % of carboxymethyl cellulose and 5.5 wt % of styrene-butadiene rubber were mixed in water.

[0127] The negative electrode, the solid electrolyte layer according to Example 1 and the lithium metal counter electrode were used to fabricate an all-solid-state half-cell.

[0128] (Example 3)

[0129] A negative electrode was manufactured in the same manner as in Example 1, except that 77.1 wt % of carbon black, 4.6 wt % of Ag having an average size of 60 nm, 10.0 wt % of montmorillonite, 2.8 wt % of carboxymethyl cellulose and 5.5 wt % of styrene-butadiene rubber were mixed in water.

[0130] The negative electrode, the solid electrolyte layer according to Example 1 and the lithium metal counter electrode were used to fabricate an all-solid-state half-cell.

[0131] (Example 4)

[0132] A negative electrode was manufactured in the same manner as in Example 1, except that 68.0 wt % of carbon black, 3.7 wt % of Ag having an average size of 60 nm, 20.0 wt % of montmorillonite, 2.8 wt % of carboxymethyl cellulose and 5.5 wt % of styrene-butadiene rubber were mixed in water.

[0133] The negative electrode, the solid electrolyte layer according to Example 1 and the lithium metal counter electrode were used to fabricate an all-solid-state half-cell.

[0134] (Example 5)

[0135] A negative electrode was manufactured in the same manner as in Example 1, except that 58.0 wt % of carbon black, 3.7 wt % of Ag having an average size of 60 nm, 30.0 wt % of montmorillonite, 2.8 wt % of carboxymethyl cellulose and 5.5 wt % of styrene-butadiene rubber were mixed in water.

[0136] The negative electrode, the solid electrolyte layer according to Example 1 and the lithium metal counter electrode were used to fabricate an all-solid-state half-cell.

[0137] (Example 6)

[0138] A negative electrode was manufactured in the same manner as in Example 1, except that 68.0 wt% of carbon black, 3.7 wt% of Ag having an average size of 60 nm, 20.0 wt% of halloysite (specific surface area: 50 m 2 / g), 2.8wt% of carboxymethyl cellulose and 5.5wt% of styrene-butadiene rubber.

[0139] The negative electrode, the solid electrolyte layer according to Example 1 and the lithium metal counter electrode were used to fabricate an all-solid-state half-cell.

[0140] (Comparative Example 1)

[0141] A negative electrode was manufactured in the same manner as in Example 1, except that 87.1 wt % of carbon black, 4.6 wt % of Ag having an average size of 60 nm, 2.8 wt % of carboxymethyl cellulose, and 5.5 wt % of styrene-butadiene rubber were mixed in water.

[0142] The negative electrode, the solid electrolyte layer according to Example 1 and the lithium metal counter electrode were used to fabricate an all-solid-state half-cell.

[0143] (Comparative Example 2)

[0144] A negative electrode was manufactured in the same manner as in Example 1, except that 81.7 wt % of carbon black, 10.0 wt % of montmorillonite, 2.8 wt % of carboxymethyl cellulose, and 5.5 wt % of styrene-butadiene rubber were mixed in water.

[0145] The negative electrode, the solid electrolyte layer according to Example 1 and the lithium metal counter electrode were used to fabricate an all-solid-state half-cell.

[0146] (Comparative Example 3)

[0147] A negative electrode was manufactured in the same manner as in Example 1, except that 71.7 wt % of carbon black, 20.0 wt % of montmorillonite, 2.8 wt % of carboxymethyl cellulose, and 5.5 wt % of styrene-butadiene rubber were mixed in water.

[0148] The negative electrode, the solid electrolyte layer according to Example 1 and the lithium metal counter electrode were used to fabricate an all-solid-state half-cell.

[0149] (Reference Example 1)

[0150] A negative electrode was manufactured in the same manner as in Example 1, except that 53.0 wt % of carbon black, 3.7 wt % of Ag having an average size of 60 nm, 35.0 wt % of montmorillonite, 2.8 wt % of carboxymethyl cellulose and 5.5 wt % of styrene-butadiene rubber were mixed in water.

[0151] The negative electrode, the solid electrolyte layer according to Example 1 and the lithium metal counter electrode were used to fabricate an all-solid-state half-cell.

[0152] (Reference Example 2)

[0153] A negative electrode was manufactured in the same manner as in Example 1, except that 38.0 wt % of carbon black, 3.7 wt % of Ag having an average size of 60 nm, 50.0 wt % of montmorillonite, 2.8 wt % of carboxymethyl cellulose and 5.5 wt % of styrene-butadiene rubber were mixed in water.

[0154] The negative electrode, the solid electrolyte layer according to Example 1 and the lithium metal counter electrode were used to fabricate an all-solid-state half-cell.

[0155] Experimental Example 1) FE-SEM (Field Emission Scanning Electron Microscope) Measurement

[0156] The cross-sectional FE-SEM image of the negative electrode manufactured in Example 1 is Figure 3 As shown in Figure 4 , montmorillonite is present in the negative electrode catalyst layer of the negative electrode.

[0157] Experimental Example 2) EDAX (Energy Dispersive X-ray Spectroscopy) Measurement

[0158] The negative electrode of Example 1 was cut into cross sections by using FIB (focused ion beam) to analyze the cross-sectional shape and element distribution analysis by energy dispersive X-ray spectroscopy (EDAX), and the results were respectively given in Figure 4 are shown in (a) and (b).

[0159] In addition, after analyzing the cross-sectional shape and element distribution of the negative electrode active material of Comparative Example 1 according to energy dispersive X-ray spectroscopy (EDAX), the results were respectively Figure 5 are shown in (a) and (b).

[0160] like Figure 4 As shown in (a), it is confirmed that the negative electrode of Example 1 contains montmorillonite (MMT) and silver, which is shown in Figure 4 This is supported by the detection of O, Na, Mg, Al, Si and Ag in the elemental analysis shown in (b).

[0161] On the contrary, Figure 5 As shown in (a), the negative electrode of Comparative Example 1 contains only silver, which is Figure 5 This is supported by the fact that only Al, Si and Ag were detected in the elemental analysis shown in (b). Figure 5 In the result of (b), Al and Si are impurities.

[0162] Experimental Example 3) Coulombic efficiency (CE) evaluation

[0163] The all-solid-state half-cells according to Examples 1 to 5 and Comparative Examples 2 and 3 were charged three times at 0.05 C. The percentage of discharge capacity to charge capacity in each cycle was calculated. The results are shown in CE in Table 1.

[0164] Experimental Example 4) Overvoltage Evaluation

[0165] The all-solid-state half-cells of Examples 1 to 5 and Comparative Examples 2 and 3 were charged and discharged three times under charging conditions of 0.05C (0.27mA) and 20 hours cutoff (SOC100, a charging state at which 100% charging capacity is reached based on 100% total battery charging capacity), and under discharging conditions of 0.27mA (0.05C) and 1.5V cutoff. The voltage of the battery cell was measured, which began to decrease at OCV (open circuit voltage, about 2.5V) until a point of inflection appeared at a voltage of about 0mV. The results of each cycle are shown in the overvoltage in Table 1.

[0166] In Table 1, the first result is shown for the first charge, and the second result is shown for the second cycle. In Table 1, the first result is shown for the first charge, and the second result is shown for the second cycle. The results are shown in Table 1. In addition, among these results, the results of Example 3 and Example 4 and Comparative Example 2 and Comparative Example 3 are shown in Table 1. Figure 6 Shown in.

[0167] (Table 1)

[0168]

[0169] As shown in Table 1, the all-solid-state half-cells of Examples 1 to 5 exhibit excellent coulombic efficiency and overvoltage characteristics.

[0170] In Comparative Examples 2 and 3, which included MMT but not Ag in the negative electrode catalyst layer, overcharge was measured during the first initial charge, but short circuit occurred thereafter, making it impossible to measure the coulombic efficiency. Accordingly, the all-solid-state half-cells of Comparative Examples 2 and 3 proved difficult to use in practice. In addition, as Figure 6 As shown in FIG. 2 , Comparative Examples 2 and 3 clearly demonstrate that a short circuit occurs.

[0171] also, Figure 7 is a graph showing the discharge characteristics of the second cycle of Examples 1 to 5, and Figure 8 is a graph showing their charging characteristics. Figure 7 , the examples have an overall low overvoltage of about 20 mV, which demonstrates excellent electrochemical properties. Figure 8 The efficiency characteristic inversely proportional to the overvoltage size is shown. In particular, Example 4 using 20 wt% of clay shows the most outstanding effect. Referring to these results, the addition of clay improves the electrochemical performance during charge / discharge.

[0172] While the disclosure has been described in connection with what are presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but on the contrary is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the claims.

Claims

1. A negative electrode for an all-solid-state battery, comprising: a current collector; and A negative electrode catalyst layer is disposed on the current collector and includes an amorphous carbon metal and clay.

2. The negative electrode for an all-solid-state battery according to claim 1, wherein The amount of the clay is 1 wt% to 30 wt% based on 100 wt% of the total negative electrode catalyst layer.

3. The negative electrode for an all-solid-state battery according to claim 1, wherein The amount of the clay is 10 wt % to 25 wt % based on 100 wt % of the total negative electrode catalyst layer.

4. The negative electrode for an all-solid-state battery according to claim 1, wherein The clay is montmorillonite (MMT), halloysite, bentonite, kaolinite, saponite, surface-modified clay, pyrophyllite-talc, fluorohectorite, vermiculite, illite, mica, brittle mica or a combination thereof.

5. The negative electrode for an all-solid-state battery according to claim 1, wherein the metal is Ag, Au, Sn, Zn, Al, Mg, Ge, Cu, In, Ni, Bi, Pt, Pd or a combination thereof.

6. The negative electrode for an all-solid-state battery as claimed in claim 1, wherein the amorphous carbon comprises carbon black, acetylene black, superconducting acetylene black, Ketjen black, furnace black, activated carbon or a combination thereof.

7. The negative electrode for an all-solid-state battery as claimed in claim 1, wherein the amorphous carbon comprises carbon black, acetylene black, superconductive acetylene black, Ketjen black or a combination thereof.

8. The negative electrode for an all-solid-state battery according to claim 1, wherein the BET specific surface area of ​​the clay is 5 m 2 / g~500m 2 / g. 9 . The negative electrode for an all-solid-state battery according to claim 1 , wherein the amount of the metal is 1 wt % to 50 wt % based on 100 wt % of the total weight of the negative electrode catalyst layer. 10 . The negative electrode for an all-solid-state battery as claimed in claim 1 , wherein the amount of the amorphous carbon is 20 wt % to 98 wt % based on 100 wt % of the total weight of the negative electrode catalyst layer.

11. An all-solid-state battery, include: The negative electrode according to any one of claims 1 to 10; Positive electrode; as well as A solid electrolyte layer is between the negative electrode and the positive electrode. 12 . The all-solid-state battery of claim 11 , wherein the negative electrode further comprises a lithium-containing layer between the current collector and the negative electrode catalyst layer.

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