All-solid-state battery

Abstract

The present invention relates to an all-solid-state battery including a positive electrode including a positive electrode active material layer containing a positive electrode active material, a negative electrode including a negative electrode catalyst layer containing a negative electrode catalyst and Nb2O5, and an electrolyte, in which the negative electrode catalyst layer contains Nb2O5 in an amount of 1-30 wt% based on a total of 100 wt% of the negative electrode catalyst layer, and the ratio (N / P) of the capacity of the negative electrode catalyst layer to the capacity of the positive electrode is between 0.1 (inclusive) and 0.5 (exclusive).

Description

Technical Field

[0001] Embodiments relate to all-solid-state batteries. Background Art

[0002] Recently, with the rapid popularization of electronic devices (such as mobile phones, laptop computers and electric vehicles) using batteries, the demand for small, lightweight and relatively high-capacity rechargeable batteries has increased rapidly. In particular, rechargeable lithium batteries have recently attracted attention as a driving power source for portable devices because they have lighter weight and high energy density. Therefore, research is being actively conducted to improve the performance of rechargeable lithium batteries.

[0003] In rechargeable lithium batteries, the term all-solid-state battery refers to a battery in which all materials are solid, and an all-solid-state battery may be a battery using a solid electrolyte. The solid electrolyte may be located between the positive electrode and the negative electrode, thereby preventing direct contact between the positive electrode and the negative electrode, and at the same time, the solid electrolyte may serve as a channel for lithium ions to move during charging and discharging. Summary of the invention

[0004] Technical issues

[0005] One embodiment provides an all-solid-state battery that exhibits excellent electrochemical performance.

[0006] Technical Solution

[0007] The embodiment can provide an all-solid-state battery, the all-solid-state battery comprising: a positive electrode, which includes a positive electrode active material layer containing a positive electrode active material; a negative electrode, which includes a negative electrode catalyst and Nb 2 O 5 A negative electrode catalyst layer; and an electrolyte, wherein based on a total of 100 wt% of the negative electrode catalyst layer, Nb 2 O 5 The amount is 1 wt% to 30 wt%, and the ratio (N / P) of the capacity of the negative electrode catalyst layer to the capacity of the positive electrode is 0.1 or more and less than 0.5.

[0008] Based on 100 wt% of the total amount of the negative electrode catalyst layer, Nb 2 O 5 The amount may be 3 wt% to 30 wt% or 5 wt% to 15 wt%.

[0009] The ratio of the capacity of the negative electrode catalyst layer to the capacity of the positive electrode (N / P) may be 0.1 to 0.4, or 0.1 to 0.3.

[0010] The negative electrode catalyst may be a carbon material, metal particles or a combination thereof.

[0011] The carbon-based material may be amorphous carbon.

[0012] The metal particles may be at least one selected from Ag, Zn, Al, Sn, Mg, Ge, Cu, In, Ni, Bi, Au, Si, Pt, Pd, and combinations thereof.

[0013] The electrolyte may be a solid electrolyte. The solid electrolyte may be a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a halide-based solid electrolyte, or a solid polymer electrolyte.

[0014] The negative electrode may further include a current collector supporting the negative electrode catalyst layer, and may further include a lithium precipitation layer formed between the current collector and the negative electrode catalyst layer during initial charge.

[0015] The positive electrode active material may be an active material or a sulfur compound that can reversibly intercalate and deintercalate lithium ions. In some embodiments, the positive electrode active material may be an active material that can reversibly intercalate and deintercalate lithium ions.

[0016] Beneficial Effects

[0017] An all-solid-state battery according to an embodiment may exhibit improved ion conductivity and high-rate characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic cross-sectional view of an all-solid-state battery according to one embodiment.

[0019] Figure 2 A schematic cross-sectional view illustrating a state of an all-solid-state battery after charging according to one embodiment.

[0020] Figure 3 is a SEM image of the surface of the negative electrode according to Example 1.

[0021] Figure 4 It is a graph showing the EDAX results of the negative electrode of Example 1.

[0022] Figure 5 To show the 20,000 times magnification Figure 3 Images of SEM images.

[0023] Figure 6 To show Figure 5 Graphs of the EDAX results for selected area 1 and selected area 2. DETAILED DESCRIPTION

[0024] 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.

[0025] It will also be understood that when a layer or element is referred to as being “on” another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may also be present.

[0026] In an embodiment, the term "particle size" or "particle diameter" may refer to an average particle diameter. The term "average particle diameter" may refer to an average particle diameter (D50) at a cumulative volume of 50% by volume in a particle size distribution. The above particle diameter can be measured, for example, by electron microscopic observation using a scanning electron microscope (SEM), a field emission scanning electron microscope (FE-SEM), or by a laser diffraction method. When measured by a laser diffraction method, more specifically, the particles to be measured are dispersed in a dispersion medium, introduced into a commercially available laser diffraction particle size measuring device (e.g., MT 3000 from Microtrac), and after irradiating 28kHz ultrasonic waves at a power of 60W, the average particle diameter (D50) based on the average particle diameter 50% in the measuring device can be calculated.

[0027] The all-solid-state battery according to the embodiment may include a positive electrode, a negative electrode, and an electrolyte, wherein the negative electrode may include a negative electrode active material layer including a negative electrode catalyst and Nb 2 O 5 , and a ratio (N / P) of the capacity of the negative electrode catalyst layer to the capacity of the positive electrode may be 0.1 or more and less than 0.5.

[0028] In some embodiments, the term negative electrode including a negative electrode catalyst layer may refer to a precipitation type negative electrode, and such a precipitation type negative electrode may not include a negative electrode active material in the preparation of a battery assembly, but instead, lithium metal may be precipitated during charging of the battery to be used as a negative electrode active material. To explain this in more detail, during charging of an all-solid-state battery, lithium ions may be released from the positive electrode active material and may move through the solid electrolyte to the negative electrode, and therefore, lithium ions may be precipitated on the negative electrode current collector to form a lithium precipitation layer between the current collector and the negative electrode layer, and the negative electrode having the lithium precipitation layer is referred to as a precipitation layer negative electrode.

[0029] The negative electrode according to some embodiments may include Nb in the negative electrode catalyst layer. 2 O 5 . Nb 2 O 5 It is a lithium-philic material and can be converted to Li during charging x Nb 2 O 5 As a result, it can operate as a pseudocapacitor to distribute or store lithium. Therefore, the ionic conductivity characteristics of the negative electrode can be improved.

[0030] By using Nb in the negative electrode of a battery having a ratio of the capacity of the negative electrode catalyst layer to the capacity of the positive electrode (N / P, hereinafter, referred to as “N / P” ratio) of 0.1 or more and less than 0.5 2 O 5 , and Nb is used in an amount of 1 wt% to 30 wt% based on 100 wt% of the total amount of the negative electrode catalyst layer. 2 O 5 , this effect can be achieved.

[0031] In some embodiments, the N / P ratio does not indicate the ratio of the capacity of the negative electrode to the capacity of the positive electrode defined in a common lithium-ion secondary battery, but indicates the ratio of the capacity of the negative electrode catalyst layer to the capacity of the positive electrode. In this article, the term capacity refers to the charging capacity. In addition, when lithium ions move to the negative electrode side during charging and exist in the negative electrode catalyst layer, the capacity of the negative electrode catalyst layer can be measured based on the capacity of lithium ions, especially the charging capacity.

[0032] In some embodiments, the capacity of the negative electrode catalyst layer can be obtained by charging a half cell including a negative electrode and a lithium counter electrode once at 0.01C to 0.1C to measure the capacity until an inflection point close to 0mV (relative to Li). The capacity of the positive electrode can be obtained from the theoretical capacity of the positive electrode active material.

[0033] If the negative electrode catalyst layer includes Nb in an amount less than 1 wt % 2 O 5 , then this amount may not be sufficient to provide the above indicated range of Nb 2 O 5 The effect obtained. 2 O 5 The high irreversible capacity and low conductivity of more than 30wt% Nb 2 O 5 Serious disadvantages will occur.

[0034] Even if Nb 2 O 5 If the amount of Nb 2 O 5 The desired effect may not be achieved when used in a battery having an N / P ratio not in the range of 0.1 or more and less than 0.5. 2 O 5 If used in a battery having an N / P ratio of less than 0.1, the negative electrode catalyst layer may not function properly and lithium may grow unevenly. 2 O 5Used in a battery having an N / P ratio of 0.5 or higher, too much lithium may be absorbed in the negative electrode catalyst layer, and therefore, irreversible capacity may occur due to dead lithium that does not participate in the charge and discharge reactions. An increase in the N / P ratio of the battery will result in an increase in the thickness of the negative electrode. In an all-solid-state battery according to some embodiments, the negative electrode may not include any solid electrolyte, and the lithium ion conductivity is low, so the increase in the thickness of the negative electrode may not easily allow charging and discharging, thereby failing to demonstrate the target effect.

[0035] In addition, when the N / P ratio is less than 1, generally speaking, during the charging process, the lithium ions that move to the negative electrode side react to form LiC x(x＝1-6) (the capacity at the open circuit voltage (0V) relative to Li+ / Li during the initial charge), and the remaining ions not participating in the reaction are precipitated between the negative electrode catalyst layer and the current collector, which means that a precipitation-type negative electrode is formed. In this embodiment, since the maximum value is less than 0.5, it can be regarded as a battery with a larger amount of lithium precipitated on the negative electrode surface compared to a typical precipitation-type negative electrode.

[0036] In some embodiments, based on 100 wt % of the total amount of the negative electrode catalyst layer, Nb 2 O 5 The amount may be 1 wt% to 30 wt%, 3 wt% to 30 wt%, 3 wt% to 20 wt%, 5 wt% to 15 wt% or 5 wt% to 10 wt%.

[0037] In some embodiments, the N / P ratio may be 0.1 or more and less than 0.5, 0.1 to 0.4, or 0.1 to 0.3, or 0.1 to 0.2.

[0038] The negative electrode catalyst layer may include a carbon material, metal particles or a combination thereof as a negative electrode catalyst. If the all-solid-state battery according to the embodiment is charged, lithium ions may be released from the positive electrode active material and may move to the negative electrode through the solid electrolyte, so that lithium ions may be precipitated on the negative electrode current collector to form a lithium precipitation layer. The carbon material may be a sp3-rich carbon material that is conducive to precipitation. For example, the carbon material may be carbon black, acetylene black, superconducting acetylene black, Ketjen black, furnace black, activated carbon, graphene or a combination thereof. Carbon black may be Super P (available from Timcal, Ltd.). Amorphous carbon is not limited thereto, and any available material that can be classified as amorphous carbon may be used.

[0039] The amorphous carbon may include single particles, secondary particles in which primary particles are aggregated, or a combination thereof.

[0040] A single particle may have a particle size of 10 nm to 60 μm. In other embodiments, the particle size of the primary particle may be 20 nm to 100 nm, and the particle size of the secondary particle may be 1 μm to 20 μm.

[0041] In some embodiments, the particle size of the primary particles may be 20 nm or more, 30 nm or more, 40 nm or more, 50 nm or more, 60 nm or more, 70 nm or more, 80 nm or more, or 90 nm or more, and 100 nm or less, 90 nm or less, 80 nm or less, 70 nm or less, 60 nm or less, 50 nm or less, 40 nm or less, or 30 nm or less.

[0042] In some embodiments, the particle size of the secondary particles may be 1 μm or greater, 3 μm or greater, 5 μm or greater, 7 μm or greater, 10 μm or greater, or 15 μm or greater, and 20 μm or less, 15 μm or less, 10 μm or less, 7 μm or less, 5 μm or less, or 3 μm or less.

[0043] The shape of the primary particles may be spherical, elliptical, plate-like, or a combination thereof. In some embodiments, the shape of the primary particles may be spherical, elliptical, or a combination thereof.

[0044] The metal nanoparticles may be Ag, Zn, Al, Sn, Mg, Ge, Cu, In, Ni, Bi, Au, Si, Pt, Pd, and combinations thereof. In some embodiments, the metal nanoparticles may be Ag. Including metal nanoparticles in the negative electrode catalyst layer may further improve the conductivity of the negative electrode.

[0045] The metal particles may have a size of 5 nm to 800 nm. The size of the metal particles may be 5 nm or more, 50 nm or more, 100 nm or more, 150 nm or more, 200 nm or more, 250 nm or more, 300 nm or more, 350 nm or more, 400 nm or more, 450 nm or more, 500 nm or more, 550 nm or more, 600 nm or more, 650 nm or more, 700 nm or more, or 750 nm or more. The size of the metal particles may be 800 nm or less, 750 nm or less, 700 nm or less, 650 nm or less, 600 nm or less, 550 nm or less, 500 nm or less, 450 nm or less, 400 nm or less, 350 nm or less, 300 nm or less, 250 nm or less, 200 nm or less, 150 nm or less, 100 nm or less, or 50 nm or less. If the size of the metal particles is within the above range, the battery characteristics (eg, cycle life characteristics) of the all-solid-state battery may be improved.

[0046] If the negative electrode catalyst layer includes the carbon-based material and the metal particles, the mixing ratio of the carbon-based material and the metal particles may be 1:1 to 99:1 by weight. For example, the amount of the carbon-based material may be 1 or more, 2 or more, 3 or more, 4 or more, 5 or more, 10 or more, 15 or more, 20 or more, 25 or more, 30 or more, 35 or more, 40 or more, 45 or more, 50 or more, 55 or more, 60 or more, 65 or more, 70 or more, 75 or more, 80 or more, 85 or more, 90 or more or 95 or more, and 99 or less, 95 or less, 90 or less, 85 or less, 80 or less, 75 or less, 70 or less, 65 or less, 60 or less, 55 or less, 50 or less, 45 or less, 40 or less, 35 or less, 30 or less, 25 or less, 20 or less, 15 or less, 10 or less, 5 or less, 4 or less, 3 or less or 2 or less, based on the metal particles. For example, the weight ratio of the carbon material to the metal particles may be 1: 1 to 5: 1, 1: 1 to 10: 1, 1: 1 to 20: 1, 1: 1 to 25: 1, 1: 1 to 30: 1, 1: 1 to 40: 1, 1: 1 to 50: 1, 1: 1 to 60: 1, 1: 1 to 70: 1, 1: 1 to 80: 1, or 1: 1 to 90: 1. If the weight ratio of the carbon material to the metal particles is within this range, the conductivity of the negative electrode can be further improved.

[0047] The carbon-based material, the metal particles, or a combination thereof may be present in an amount of 50 wt % to 98 wt % or 60 wt % to 90 wt % based on the total weight of the negative electrode catalyst layer.

[0048] The negative electrode catalyst layer may include a binder, and may further include a conductive material.

[0049] The binder may be, for example, styrene butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, vinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, polymethyl methacrylate, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, or a combination thereof. Carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose may be alkali metal salts thereof, and the alkali metal may be Na or Li. As a non-limiting example, any available binder in the relevant art may be used as the binder.

[0050] The amount of the binder may be 0.1 wt % to 30 wt % or 0.1 wt % to 10 wt % based on the total weight of each component of the negative electrode for an all-solid-state battery or the total weight of the negative electrode catalyst layer. The binder within the above range may fully exhibit adhesion without deteriorating battery performance.

[0051] The conductive material is included to provide the electrode with conductivity, and any conductive material can be used as the conductive material as long as it does not cause chemical changes. Examples of the conductive material may be carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, and carbon nanotube, etc.; metal-based materials including metal powders or metal fibers of copper, nickel, aluminum, and silver, etc.; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0052] Based on the total weight of each component of the negative electrode for an all-solid-state battery, or the total weight of the negative electrode catalyst layer, the conductive material may be included in an amount of 0.1 wt% to 15 wt% or 0.1 wt% to 10 wt%. The conductive material within the above range can fully exhibit electrical conductivity without deteriorating battery performance.

[0053] The negative electrode may further include a current collector supporting the negative electrode catalyst layer. The current collector may be, 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 have a foil shape or a sheet shape.

[0054] The negative electrode catalyst layer may further include, for example, additives such as a filler, a dispersant, and an ion conductive material, etc. As the filler, the dispersant, and the ion conductive material included in the negative electrode catalyst layer, materials generally used for all-solid-state batteries can be used.

[0055] The positive electrode may include a positive active material layer containing a positive active material and a current collector supporting the positive active material layer.

[0056] The positive electrode active material may include a compound that reversibly intercalates and deintercalates lithium ions. For example, the positive electrode active material may include one or more composite oxides of a metal selected from cobalt, manganese, nickel, and combinations thereof and lithium. Examples of the positive electrode active material may be 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 1c (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-c Co 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 Mn 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 NeG 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 .

[0057] In the chemical formula, A is selected from Ni, Co, Mn or a combination thereof; B 1 Selected from Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements or combinations thereof; D 1 is selected from O, F, S, P or a combination thereof; E is selected from Co, Mn or a combination thereof; F 1selected from F, S, P, or a combination thereof; G is selected from Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; Q is selected from Ti, Mo, Mn, or a combination thereof; I 1 selected from Cr, V, Fe, Sc, Y, or a combination thereof; J is selected from V, Cr, Mn, Co, Ni, Cu, or a combination thereof.

[0058] According to some embodiments, the positive electrode active material may be a three - group - classified lithium transition metal oxide, such as LiNi x Co y Al z O 2 (NCA), LiNi x Co y Mn z O 2 (NCM) (where 0 < x < 1, 0 < y < 1, 0 < z < 1, and x + y + z = 1), etc.

[0059] The compound may have a coating on its surface or may be mixed with another compound having a coating. The coating may include at least one coating - element compound selected from oxides of coating elements, hydroxides of coating elements, hydroxy - oxides of coating elements, oxy - carbonates of coating elements, and hydroxy - carbonates of coating elements. The compound used for the coating may be amorphous or crystalline. The coating elements 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, a coating can be provided by a method that has no (or substantially no) adverse effect on the properties of the positive electrode active material, and for example, the method may include any suitable coating method, such as spraying and / or dipping, etc., but is not explained in more detail because those of ordinary skill in the art should easily recognize this after reading this disclosure.

[0060] In addition, as the coating, any coating known to be applicable to the positive electrode active material coating of a solid - state battery can be applied, and examples thereof include Li 2 O - ZrO 2 (LZO), etc.

[0061] The shape of the positive electrode active material may be, for example, a particulate shape, such as a spherical shape or an ellipsoidal shape, and the average particle size of the positive electrode active material may not be restricted and may be within any range applicable to the positive electrode active material of a conventional all - solid - state secondary battery. The amount of the positive electrode active material included in the positive electrode active material may not be restricted and may be within any range applicable to the positive electrode active material of a conventional all - solid - state secondary battery.

[0062] In some embodiments, the positive electrode active material may be included in an amount of 55 wt% to 99.7 wt%, or for example 74 wt% to 89.8 wt%, based on the total weight of the positive electrode active material layer. If the positive electrode active material is included within this range, the capacity of the all-solid-state battery can be maximized, and the cycle life characteristics can be improved.

[0063] The positive electrode active material layer may include 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 solid polymer electrolyte.

[0064] 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 2 S-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 S 5 -Z m S n (wherein m and n are each an integer, and Z is Ge, Zn or Ga), Li 2 S-GeS 2 , Li 2 S-SiS 2 -Li 3 PO4 or Li 2 S-SiS 2 -Li p MO q (wherein p and q are each integers, and M is P, Si, Ge, B, Al, Ga or In), etc.

[0065] The sulfide-based solid electrolyte can be prepared by mixing Li 2 S and P 2 S 5 At this mixing ratio, a sulfide-based solid electrolyte exhibiting excellent ionic conductivity can be prepared. As other components, SiS 2 ,GeS 2 or B 2 S 3 The like may be further included therein, thereby further improving ionic conductivity. The mixing process is carried out by mechanical grinding or by a solution method. Mechanical grinding can be carried out by adding starting materials, grinding balls, etc. in a reactor and stirring vigorously to crush the starting materials and mix them together. The solution method can provide a solid electrolyte as a precipitate by mixing the starting materials in a solvent. After mixing, an additional sintering process can be carried out. The crystals of the solid electrolyte can be further solidified by adding sintering.

[0066] For example, the solid electrolyte may be an Argentite-type sulfide-based solid electrolyte. The sulfide-based 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 greater and 12 or less, M is Ge, Sn, Si or a combination thereof, and A is one of F, Cl, Br or I), and in another embodiment, may be Li 3 PS 4 , Li 7 P 3 S 11 , Li 6 PS 5 Cl, Li 6 PS 5 Br or Li 6 PS 5 I etc.

[0067] The sulfide-based solid electrolyte may be amorphous, crystalline, or a combination thereof.

[0068] The oxide-based inorganic solid electrolyte may be, for example, Li 1+x Ti 2-xAl(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 )O 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), Li 1+x+y (Al, Ga) x (Ti, Ge) 2-x Si y P 3-y O 12 (0 ≤ x ≤ 1, 0 ≤ y ≤ 1), Lanthanum lithium titanate (Li x La y TiO 3 , 0 < x < 2, 0 < y < 3), Li 2 O, LiAlO 2 、Li 2 O - Al 2 O 3 -SiO 2 -P 2O 5 -TiO 2 -GeO 2 Ceramics, garnet ceramicsLi 3+x La 3 M 2 O 12 (M = Te, Nb or Zr; x is an integer from 1 to 10) or a mixture thereof.

[0069] The solid polymer electrolyte may be, for example, polyethylene oxide, poly(diallyldimethylammonium) trifluoromethanesulfonimide (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 Zr 2 Si 2 PO 12 , Li 3 Zr 2 Si 2 PO 12 、Na 5 ZGar 3 O 12 、Na 5 TiP 3 O 12 、Na 3 Fe 2 P 3 O 12 、Na 4 Nb 3 O12 , 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, or 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 , Li1 +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 T i2-x Si y P 3-y O 12 (0 < x ≤ 0.4, 0 < y ≤ 0.6, and Q is Al or Ga), Li 6 B a La 2 Ta 2 O 12 , Li 7 La 3 Zr 2 O 12 , Li 5 La 3 Nb 2 O 12 , Li 5 La 3 M 2 O 12 (M is Nb, Ta) or Li 7+x A x La 3-x Zr 2 O 12 (0 < x < 3 and A is Zn), or at least one of the above.

[0070] The solid electrolyte may have a particle shape, and may have an average particle diameter (D50) of 5.0 μm or less, 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.

[0071] The amount of the solid electrolyte may be 0.1 wt% to 35 wt%, and for example, 1 wt% to 35 wt%, 5 wt% to 30 wt%, 8 wt% to 25 wt%, or 10 wt% to 20 wt%, based on the weight of the negative electrode catalyst layer.

[0072] Based on the total weight of the positive electrode active material layer, the solid electrolyte may be included in an amount of 0.1wt% to 35wt%, and for example 1wt% to 35wt%, 5wt% to 30wt%, 8wt% to 25wt% or 10wt% to 20wt%. Based on the total weight of the positive electrode active material and the solid electrolyte in the positive electrode active material layer, the positive electrode active material may be included in an amount of 65wt% to 99wt%, and the solid electrolyte may be included in an amount of 1wt% to 35wt%, and in another embodiment, the positive electrode active material may be included in an amount of 80wt% to 90wt%, and the solid electrolyte may be included in an amount of 10wt% to 20wt%. If a solid electrolyte in this weight range is included in the positive electrode, the cycle life characteristics and efficiency of the all-solid-state battery can be improved without degrading the capacity.

[0073] The positive electrode active material layer may include a binder. The binder may improve the binding properties between the positive electrode active material particles and between the positive electrode active material particles and the current collector.

[0074] As non-limiting examples, the binder may be 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, vinylidene fluoride-hexafluoropropylene copolymer, polyethylene, polypropylene, styrene butadiene rubber, acrylated styrene butadiene rubber, polyacrylonitrile, epoxy resin, nylon, poly(meth)acrylate or polymethyl(meth)acrylate, etc.

[0075] Among them, the binder according to some embodiments may be at least one selected from polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polytetrafluoroethylene, styrene butadiene rubber, polyacrylonitrile or polymethyl (meth)acrylate.

[0076] The binder may be 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 the total weight of the positive electrode active material layer. Within this amount range, adhesion can be sufficiently ensured without deteriorating battery performance.

[0077] The positive electrode active material layer may further include a conductive material. The conductive material may be included to provide electrode conductivity, and any conductive material that does not cause chemical changes may be used as the conductive material. Examples of the conductive material may include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, and carbon nanotube; metal-based materials including metal powders or metal fibers of copper, nickel, aluminum, and silver; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0078] Based on the total amount of each component of the positive electrode for an all-solid-state battery, or the total amount of the positive active material layer, the conductive material may be included at 0.1 wt% to 5 wt% or 0.1 wt% to 3 wt%. The conductive material within the above range may improve conductivity without deteriorating battery performance.

[0079] The current collector may be, 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 have a foil shape or a thin sheet shape.

[0080] The electrolyte layer may include a solid electrolyte. The solid electrolyte may be an inorganic solid electrolyte (such as a sulfide-based solid electrolyte, an oxide-based solid electrolyte, a halide-based solid electrolyte, etc.) or a solid polymer electrolyte.

[0081] The sulfide-based solid electrolyte, oxide-based solid electrolyte, and solid polymer electrolyte are as described above.

[0082] The halide solid electrolyte may include a Li element, an M element (wherein M is a metal other than Li) and an X element (wherein X is a halogen). X may be, for example, F, Cl, Br, and I. In some embodiments, the halide solid electrolyte may include at least one of Br and Cl as X. M may be, for example, a metal element such as Sc, Y, B, Al, Ga, and In.

[0083] The composition of the halide-based solid electrolyte is not limited, but in some embodiments, the halide-based solid electrolyte may be composed of Li 6-3a M a Br b Cl crepresentation (where M is a metal other than Li, 0 < a < 2, 0 ≤ b ≤ 6, 0 ≤ c ≤ 6, b + c = 6). a can be 0.75 or greater, or 1 or greater. In some embodiments, a can be 1.5 or less. b can be 1 or greater, or 2 or greater. c can be 3 or greater, or 4 or greater. Examples of the halide-based solid electrolyte can be Li 3 YBr 6 、Li 3 YCl 6 或Li 3 YBr 2 Cl 4 。

[0084] The solid electrolyte can have a particulate shape and can have an average particle diameter (D50) of 5.0 μm or less, 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.

[0085] In addition to the solid electrolyte, the solid electrolyte layer can further include a binder. The binder can be styrene-butadiene rubber, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, an acrylate polymer, or a combination thereof, and can be any material commonly used in the relevant art. The acrylate polymer can be, for example, butyl acrylate, polyacrylate, polymethacrylate, or a combination thereof.

[0086] The solid electrolyte layer can be prepared by adding the solid electrolyte to a binder solution, coating the binder solution onto a substrate film, and drying the binder solution. The binder solution can include isobutyl isobutyrate, xylene, toluene, benzene, hexane, or a combination thereof, or can be a compound represented by Chemical Formula 1 and / or a compound represented by Chemical Formula 2. The preparation of the solid electrolyte layer is well known in the art, and thus its detailed description will not be repeated in the specification.

[0087] The solid electrolyte layer can have a thickness of 10 μm to 150 μm.

[0088] The solid electrolyte layer can further include an alkali metal salt and / or an ionic liquid and / or a conductive polymer.

[0089] The alkali metal salt can be, for example, a lithium salt. In the solid electrolyte layer, the amount of the lithium salt can be 1 M or more, for example, 1 M to 4 M. Having the amount of the lithium salt can improve the lithium ion mobility of the solid electrolyte layer, thereby improving the ionic conductivity.

[0090] The lithium salt can be, for example, LiSCN, LiN(CN )2 、Li(CF 3 SO 2 )3 C. LiC 4 F 9 SO 3 、LiN(SO 2 CF 2 CF 3 ) 2 , LiCl, LiF, LiBr, LiI, LiB(C 2 O 4 ) 2 , LiBF 4 , LiBF 3 (C 2 F 5 ), lithium bis(oxalate)borate (LiBOB), lithium oxalyldifluoroborate (LIODFB), lithium difluoro(oxalate)borate (LiDFOB), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI, LiN(SO 2 CF 3 ) 2 )、LiFSI、LiN(SO 2 F) 2 )、LiCF 3 SO 3 、LiAsF 6 、LiSbF 6 、LiClO 4 or a mixture thereof.

[0091] The lithium salt may be an imide-based lithium salt, and for example, the imide-based lithium salt may be lithium bis(trifluoromethanesulfonyl)imide (LiTFSI, LiN(SO 2 CF 3 ) 2 ), lithium bis(fluorosulfonyl)imide (LiFSI or LiN(SO 2 F) 2 ). The lithium salt can appropriately maintain chemical reactivity with the ionic liquid, and thus, can maintain or improve ionic conductivity.

[0092] An ionic liquid refers to a salt or room temperature molten salt composed only of ions, which has a melting point below room temperature and is in a liquid state at room temperature.

[0093] The ionic liquid may be a compound comprising: a) at least one cation selected from ammonium, pyrrolidinium, pyridinium, pyrimidinium, imidazolium, piperidinium, pyrazolium, oxazolinium, pyridazinium, phosphonium, sulfonium, triazolium or a mixture thereof, or more cations, and b) a cation selected from BF 4 - PF 6 - , AsF 6- , SbF 6 - 、AlCl 4 - , HSO 4 - , ClO 4 - , CH 3 SO 3 - CF 3 CO 2 - , Cl - Br - ,I - , BF 4 - 、SO 4 - CF 3 SO 3 - 、(FSO 2 ) 2 N-、(C 2 F 5 SO 2 ) 2 N - , (C 2 F 5 SO 2 )CF 3 SO 2 )N - or (CF 3 SO 2 ) 2 N - At least one anion.

[0094] The ionic liquid may be, for example, at least one selected from N-methyl-N-propylpyrrolidinium bis(trifluoromethylsulfonyl)imide, N-butyl-N-methylpyrrolidinium bis(3-trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide, and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide.

[0095] In the solid electrolyte layer, the weight ratio of the solid electrolyte and the ionic liquid may be 0.1:99.9 to 90:10, for example, 10:90 to 90:10, 20:80 to 90:10, 30:70 to 90:10, 40:60 to 90:10, or 50:50 to 90:10. The solid electrolyte layer within this range may have an improved electrochemical contact area with the electrode. Thus, ionic conductivity may be maintained or improved. The improved electrochemical contact area may improve the energy density, discharge capacity, or rate characteristics of the all-solid-state battery, etc.

[0096] An all-solid-state battery according to some embodiments may be referred to as an all-solid-state secondary battery or an all-solid-state lithium secondary battery.

[0097] If the all-solid-state battery according to some embodiments is charged, lithium ions may be released from the positive electrode active material and may pass through the solid electrolyte to move to the negative electrode, and thus, the lithium ions may be precipitated onto the negative electrode current collector to form a lithium precipitation layer. That is, the lithium precipitation layer may be formed between the negative electrode current collector and the negative electrode active material layer.

[0098] The charging may include a formation process which may be performed once to three times at 0.05C to 1C at 25°C to 50°C.

[0099] The lithium precipitation layer may have a thickness of 10 μm to 50 μm. For example, the thickness of the lithium precipitation layer may be 10 μm or more, 20 μm or more, 30 μm or more, or 40 μm or more, and 50 μm or less, 40 μm or less, 30 μm or less, or 20 μm or less. If the thickness of the lithium precipitation layer is within this range, lithium may be reversibly precipitated during charge and discharge, thereby further improving the cycle life characteristics.

[0100] In an embodiment, the all-solid-state battery may further include a buffer material for buffering thickness changes caused by charging and discharging. The buffer material may be located between the negative electrode and the housing, and in the case where one or more electrode assemblies are stacked in the battery, the buffer material may be located between different electrode assemblies.

[0101] The buffer material may include a material having an elastic recovery rate of 50% or more and insulating properties. In another embodiment, the buffer material may be silicone rubber, acrylic rubber, fluorine rubber, nylon, synthetic rubber or a combination thereof. The buffer material may be a polymer sheet.

[0102] Figure 1 2 is a cross-sectional view showing an all-solid-state battery according to an embodiment. Figure 1 The all-solid-state battery 100 may have a structure in which an electrode assembly formed by stacking 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 current collector 201 and a positive electrode active material layer 203 is contained in a housing (such as a bag, etc.). 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. Figure 1 An electrode assembly is shown including a negative electrode 400, a solid electrolyte layer 300, and a positive electrode 200. In some embodiments, an all-solid-state battery may be manufactured by stacking at least two electrode assemblies.

[0103] Figure 2The structure of an all-solid-state battery in a charged state is schematically shown. The all-solid-state battery 100 may include 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 and a negative electrode catalyst layer 403, and a solid electrolyte layer 300 located between the positive electrode 200 and the negative electrode 400, and also includes a battery case 500 in which these components are accommodated.

[0104] As in Figure 2 As shown in FIG. 1 , if the all-solid-state battery 100 is charged, lithium ions may be released from the positive electrode active material and deposited on the negative electrode current collector 401 ′, thereby forming a lithium deposition layer 405 ′ between the current collector 401 ′ and the negative electrode catalyst layer 403 ′.

[0105] Mode for carrying out the invention

[0106] Hereinafter, examples and comparative examples of the present disclosure are described. However, these examples should not be interpreted as limiting the scope thereof in any sense.

[0107] (Example 1)

[0108] (1) Preparation of negative electrode

[0109] 8 wt% Li-carboxymethyl cellulose binder, 5 wt% Ag nanoparticles (D50: 60 nm), 86 wt% carbon black and 1 wt% Nb 2 O 5 The mixture was mixed in a water solvent to prepare a negative electrode catalyst layer slurry. The carbon black was a mixture of single particles having a particle size of 38 nm and secondary particles, and the secondary particles had a particle size of 275 nm in which primary particles having a particle size of 76 nm were aggregated.

[0110] The slurry was coated on a stainless steel foil current collector and vacuum dried at 100° C. to prepare a negative electrode including a negative electrode catalyst layer having a thickness of 5 μm and a current collector having a thickness of 10 μm.

[0111] (2) Preparation of positive electrode

[0112] 85.00wt% LiNi 0.8 Co 0.1 Al 0.1 O 2 Positive electrode active material, 13.5wt% argyrodite-type solid electrolyte Li 6 PS 5 Cl, 0.5 wt % of carbon nanotube conductive material and 1.0 wt % of polyvinylidene fluoride binder were mixed in N-methylpyrrolidone solvent to prepare positive electrode active material layer slurry.

[0113] The positive active material layer slurry was coated on an aluminum current collector and dried at 60° C., followed by pressing to prepare a positive electrode for an all-solid-state battery.

[0114] (3) Preparation of solid electrolyte layer

[0115] Towards Argentite-type solid electrolyte Li 6 PS 5 A butyl acrylate binder solution (solid content: 50 wt%) (to which isobutyl isobutyrate as an acrylate polymer has been added) was added and mixed. The mixing ratio of the solid electrolyte and the binder was set to a weight ratio of 98.7:1.3.

[0116] Mixing was performed by using a Thinky mixer. 2 mm zirconia balls were added to the obtained mixture, and mixed repeatedly with the Thinky mixer to prepare slurry. The slurry was cast on a polytetrafluoroethylene release film and dried at room temperature to prepare a solid electrolyte layer having a thickness of 5 μm.

[0117] (4) Preparation of all-solid-state battery cells

[0118] The negative electrode, the solid electrolyte and the positive electrode are stacked in sequence and a pressure of 2 Nm is applied thereto to manufacture an all-solid-state battery cell. In the battery cell, the thickness of the positive electrode active material layer or lithium (excluding the current collector) is 100 μm to 150 μm, the thickness of the negative electrode catalyst layer (excluding the current collector) is 5 μm to 10 μm, and the thickness of the solid electrolyte layer is 100 μm.

[0119] (Example 2)

[0120] The negative electrode was prepared by the same process as in Example 1, except that 8 wt % of a mixed binder of Li-carboxymethyl cellulose (Li-CMC) and styrene butadiene rubber (SBR) (Li-CMC:SBR=1:2 weight ratio), 4 wt % of Ag nanoparticles (D50: 60 nm), 85 wt % of carbon black and 3 wt % of Nb 2 O 5 The mixture is mixed in a water solvent to prepare a negative electrode catalyst layer slurry.

[0121] An all-solid-state battery cell was manufactured by the same process as in Example 1 using the negative electrode, positive electrode and solid electrolyte of Example 1.

[0122] (Example 3)

[0123] The negative electrode was prepared by the same process as in Example 1, except that 8 wt % of a mixed binder of Li-carboxymethyl cellulose (Li-CMC) and styrene butadiene rubber (SBR) (Li-CMC:SBR=1:2 weight ratio), 4 wt % of Ag nanoparticles (D50: 60 nm), 83 wt % of carbon black and 5 wt % of Nb 2 O 5 The mixture is mixed in a water solvent to prepare a negative electrode catalyst layer slurry.

[0124] An all-solid-state battery cell was manufactured by the same process as in Example 1 using the negative electrode, positive electrode and solid electrolyte of Example 1.

[0125] (Example 4)

[0126] The negative electrode was prepared by the same process as in Example 1, except that 8 wt % of a mixed binder of Li-carboxymethyl cellulose (Li-CMC) and styrene butadiene rubber (SBR) (Li-CMC:SBR=1:2 weight ratio), 4 wt % of Ag nanoparticles (D50: 60 nm), 78 wt % of carbon black and 10 wt % of Nb 2 O 5 The mixture is mixed in a water solvent to prepare a negative electrode catalyst layer slurry.

[0127] An all-solid-state battery cell was manufactured by the same process as in Example 1 using the negative electrode, positive electrode and solid electrolyte of Example 1.

[0128] (Example 5)

[0129] The negative electrode was prepared by the same process as in Example 1, except that 8 wt % of a mixed binder of Li-carboxymethyl cellulose (Li-CMC) and styrene butadiene rubber (SBR) (Li-CMC:SBR=1:2 weight ratio), 4 wt % of Ag nanoparticles (D50: 60 nm), 64 wt % of carbon black and 25 wt % of Nb 2 O 5 The mixture is mixed in a water solvent to prepare a negative electrode catalyst layer slurry.

[0130] An all-solid-state battery cell was manufactured by the same process as in Example 1 using the negative electrode, positive electrode and solid electrolyte of Example 1.

[0131] (Example 6)

[0132] The negative electrode was prepared by the same process as in Example 1, except that 8 wt % of a mixed binder of Li-carboxymethyl cellulose (Li-CMC) and styrene butadiene rubber (SBR) (Li-CMC:SBR=1:2 weight ratio), 3 wt % of Ag nanoparticles (D50: 60 nm), 59 wt % of carbon black and 30 wt % of Nb 2 O 5 The mixture is mixed in a water solvent to prepare a negative electrode catalyst layer slurry.

[0133] An all-solid-state battery cell was manufactured by the same process as in Example 1 using the negative electrode, positive electrode and solid electrolyte of Example 1.

[0134] (Example 7)

[0135] The negative electrode was prepared by the same process as in Example 1, except that 8 wt % of a mixed binder of Li-carboxymethyl cellulose (Li-CMC) and styrene butadiene rubber (SBR) (Li-CMC:SBR=1:2 weight ratio), 82 wt % of carbon black and 10 wt % of Nb 2 O 5 The mixture is mixed in a water solvent to prepare a negative electrode catalyst layer slurry.

[0136] An all-solid-state battery cell was manufactured by the same process as in Example 1 using the negative electrode and positive electrode of Example 1 and the solid electrolyte.

[0137] (Example 8)

[0138] The negative electrode was prepared by the same process as in Example 1, except that 8 wt % of a mixed binder of Li-carboxymethyl cellulose (Li-CMC) and styrene butadiene rubber (SBR) (Li-CMC:SBR=1:2 weight ratio), 62 wt % of carbon black and 30 wt % of Nb 2 O 5 The mixture is mixed in a water solvent to prepare a negative electrode catalyst layer slurry.

[0139] An all-solid-state battery cell was manufactured by the same process as in Example 1 using the negative electrode, positive electrode and solid electrolyte of Example 1.

[0140] (Comparative Example 1)

[0141] The negative electrode was prepared by the same process as in Example 1, except that 8 wt % of a mixed binder of Li-carboxymethyl cellulose (Li-CMC) and styrene butadiene rubber (SBR) (Li-CMC:SBR=1:2 weight ratio), 4.2 wt % of Ag nanoparticles (D50: 60 nm), 87 wt % of carbon black and 0.8 wt % of Nb 2 O 5The mixture is mixed in a water solvent to prepare a negative electrode catalyst layer slurry.

[0142] An all-solid-state battery cell was manufactured by the same process as in Example 1 using the negative electrode, positive electrode and solid electrolyte of Example 1.

[0143] (Comparative Example 2)

[0144] The negative electrode was prepared by the same process as in Example 1, except that 8 wt % of a mixed binder of Li-carboxymethyl cellulose (Li-CMC) and styrene butadiene rubber (SBR) (Li-CMC:SBR=1:2 weight ratio), 3 wt % of Ag nanoparticles (D50: 60 nm), 57 wt % of carbon black and 32 wt % of Nb 2 O 5 The mixture is mixed in a water solvent to prepare a negative electrode catalyst layer slurry.

[0145] (Comparative Example 3)

[0146] The negative electrode was prepared by the same process as in Example 1, except that 8 wt % of a mixed binder of Li-carboxymethyl cellulose (Li-CMC) and styrene butadiene rubber (SBR) (Li-CMC:SBR=1:2 weight ratio), 2 wt % of Ag nanoparticles (D50: 60 nm), 40 wt % of carbon black and 50 wt % of Nb 2 O 5 The mixture is mixed in a water solvent to prepare a negative electrode catalyst layer slurry.

[0147] (Comparative Example 4)

[0148] The negative electrode was prepared by the same process as in Example 1, except that 8 wt % of a mixed binder of Li-carboxymethyl cellulose (Li-CMC) and styrene butadiene rubber (SBR) (Li-CMC:SBR=1:2 weight ratio), 60 wt % of carbon black and 32 wt % of Nb 2 O 5 The mixture is mixed in a water solvent to prepare a negative electrode catalyst layer slurry.

[0149] (Comparative Example 5)

[0150] An all-solid-state battery was manufactured by the same process as in Example 1, except that the negative electrode of Example 1 was used and the loading level was controlled so that the N / P ratio was 0.09.

[0151] (Comparative Example 6)

[0152] An all-solid-state battery was manufactured by the same process as in Example 1, except that the negative electrode of Example 1 was used and the load level was controlled so that the N / P ratio was 0.5.

[0153] (Comparative Example 7)

[0154] An all-solid-state battery was manufactured by the same process as in Example 1, except that the negative electrode of Example 6 was used and the loading level was controlled so that the N / P ratio was 0.09.

[0155] (Comparative Example 8)

[0156] An all-solid-state battery was manufactured by the same process as in Example 1, except that the negative electrode of Example 6 was used and the load level was controlled so that the N / P ratio was 0.5.

[0157] Experimental Example 1) Measurement of resistance

[0158] The resistance (sheet resistance) of the negative electrodes according to Examples 1 to 8 and Comparative Examples 1 to 8 was probed with 46 probes by a four-probe method (XF057, available from HIOKI Co., Ltd.), and the results are shown in Table 2.

[0159] Experimental Example 2) Measurement of surface roughness

[0160] The surface roughness (Ra) of the negative electrodes according to Examples 1 to 8 and Comparative Examples 1 to 8 was measured, and the results are shown in Table 2. The surface roughness is an average value obtained by adding the absolute values ​​of the deviations from the reference surface to the measurement surface, that is, a value obtained by calculating the average value of the absolute values ​​of the differences between all points on the surface and the reference surface. The surface roughness was measured by using a 3D optical microscope (Optical Microscope, available from Keyence, Co., Ltd.).

[0161] Experimental Example 3) Evaluation of overvoltage

[0162] The all-solid-state battery cells of Examples 1 to 8 and Comparative Examples 1 to 8 were charged at 0.05C, and the voltage drop started at OCV (open circuit voltage, about 2.5V). Thereafter, the voltage was measured until a point where an inflection point appeared near about 0mV. The results are shown in Table 2 as overvoltage.

[0163] Experimental Example 4) Evaluation of initial efficiency

[0164] The all-solid-state battery cells of Examples 1 to 8 and Comparative Examples 1 to 8 were charged and discharged once at 0.05 C to obtain the percentage value of the discharge capacity to the charge capacity. The results are shown in Table 2 as initial efficiency.

[0165] Experimental Example 5) Evaluation of power efficiency

[0166] The all-solid-state battery cells of Examples 1 to 6 and Comparative Examples 1 to 4 were charged at 0.05 C and discharged at 0.1 C. The percentage of the discharge capacity to the charge capacity was measured. The results are shown in Table 2 as power efficiency.

[0167] The compositions of the negative electrode catalyst layers of Examples 1 to 8 and Comparative Examples 1 to 4 are summarized in Table 1.

[0168] The N / P ratio of the all-solid-state battery cell is shown in Table 1. The N / P ratio is obtained by the ratio of the capacity of the negative electrode catalyst layer to the capacity of the positive electrode (theoretical capacity), and the theoretical capacity of the negative electrode catalyst layer is obtained by charging the half cell once at 0.05C and measuring the capacity at the inflection point close to 0mV (relative to Li).

[0169] Table 1

[0170]

[0171]

[0172] Table 2

[0173]

[0174] As shown in Table 2, the negative electrode catalyst layer includes 1 wt% to 30 wt% of Nb 2 O 5 And Examples 1 to 8 having an N / P ratio of 0.1 or more and less than 0.5 exhibited low resistance and surface roughness, low overvoltage, and excellent initial efficiency and power efficiency.

[0175] On the other hand, in the case of a very small amount of Nb 2 O 5 In the case of Comparative Example 1, the initial efficiency deteriorated and a short circuit occurred.

[0176] Using 32wt% Nb 2 O 5 Comparative Example 2 shows increased resistance and surface roughness, increased overvoltage and deteriorated initial efficiency. In the case of Comparative Example 3, if an excess of 50 wt% Nb 2 O 5 , the resistance and surface roughness increased significantly, the initial efficiency deteriorated greatly, and a short circuit occurred. Comparative Example 4, which did not use Ag, showed high cell resistance, surface roughness, low overvoltage, low initial efficiency, and a short circuit.

[0177] Even if the N / P ratio is less than 0.1 and Nb 2 O 5 Comparative Examples 5 and 7, which were used in amounts of 1 wt % and 30 wt %, also exhibited slightly lower initial efficiency and deteriorated power efficiency. 2 O 5In Comparative Examples 6 and 8 used in amounts of 1 wt % and 30 wt %, the resistance was too high to be measured, showing extremely deteriorated initial efficiency, and short circuit occurred.

[0178] Experimental Example 6) SEM images and EDAX

[0179] The negative electrode according to Example 1 was cross-polished to flatten one surface thereof. The surface SEM image of the obtained negative electrode is shown in FIG. Figure 3 The EDAX results of the negative electrode are shown in Figure 4 middle.

[0180] Will come from Figure 3 The SEM image was magnified 20,000 times and is shown in Figure 5 middle. Figure 5 The EDAX results of selected area 1 and selected area 2 in Figure 6 middle.

[0181] from Figure 4 The EDAX results show that Nb 2 O 5 Present in the negative electrode of Example 1.

[0182] In the Figure 3 In the SEM image, the bright spots indicate Nb 2 O 5 , available from Figure 6 It is clearly seen that in Figure 6 ( Figure 5 In the EDAX result of the selected area 1 in Figure 1, there are peaks of C, O and Nb, while in Figure 6 ( Figure 5 In the EDAX result of selected region 2 in FIG, only the peak of C exists.

[0183] 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 appended claims.

Claims

1. An all-solid-state battery, include: A positive electrode, the positive electrode comprising a positive electrode active material layer containing a positive electrode active material; The negative electrode comprises a negative electrode catalyst and Nb 2 O 5 a negative electrode catalyst layer; and The electrolyte layer, Based on 100 wt% of the negative electrode catalyst layer, Nb 2 O 5 The amount is 1wt% to 30wt%, and The ratio (N / P) of the capacity of the negative electrode catalyst layer to the capacity of the positive electrode is 0.1 or more and less than 0.

5.

2. The all-solid-state battery according to claim 1, wherein based on 100 wt% of the negative electrode catalyst layer in total, the Nb 2 O 5 The amount is 3wt% to 30wt%.

3. The all-solid-state battery according to claim 1, wherein based on a total of 100 wt% of the negative electrode catalyst layer, the Nb 2 O 5 The amount is 5wt% to 15wt%. 4 . The all-solid-state battery according to claim 1 , wherein the ratio (N / P) of the capacity of the negative electrode catalyst layer to the capacity of the positive electrode is 0.1 to 0.

4. 5 . The all-solid-state battery according to claim 1 , wherein the ratio (N / P) of the capacity of the negative electrode catalyst layer to the capacity of the positive electrode is 0.1 to 0.

3.

6. The all-solid-state battery according to claim 1, wherein the negative electrode catalyst is a carbon material, metal particles or a combination thereof.

7. The all-solid-state battery as claimed in claim 6, wherein the carbon-based material is amorphous carbon.

8. The all-solid-state battery of claim 6, wherein the metal particles include at least one selected from Ag, Zn, Al, Sn, Mg, Ge, Cu, In, Ni, Bi, Au, Si, Pt, Pd, and combinations thereof.

9. The all-solid-state battery of claim 1, wherein the electrolyte layer comprises a solid electrolyte. 10 . The all-solid-state battery according to claim 9 , wherein the solid electrolyte is a sulfide solid electrolyte, an oxide solid electrolyte, a halide solid electrolyte or a solid polymer electrolyte.

11. The all-solid-state battery according to claim 1, wherein the negative electrode further comprises a current collector supporting the negative electrode catalyst layer, and A lithium precipitation layer is formed between the current collector and the negative electrode catalyst layer during initial charge. 12 . The all-solid-state battery according to claim 1 , wherein the positive electrode active material is an active material or a sulfur compound that can reversibly embed and de-embed lithium ions. 13 . The all-solid-state battery according to claim 12 , wherein the positive electrode active material is an active material capable of reversibly inserting and deinserting lithium ions.

Images