All-solid-state battery

Abstract

An all-solid-state battery according to the present disclosure includes a positive electrode layer and a negative electrode layer, and a solid electrolyte layer interposed between the positive electrode layer and the negative electrode layer, in which the solid electrolyte layer includes a first electrolyte layer including a glass ceramic electrolyte and a second electrolyte layer including a glass ceramic electrolyte. The glass ceramic electrolyte includes lithium chloride (LiCl), and the second electrolyte layer is disposed on one surface or both surfaces of the first electrolyte layer and includes a lithium borosilicate (LBSO)-based electrolyte.

Description

Technical Field

[0001] The present disclosure relates to an all-solid-state battery. Background Art

[0002] The recent demand for portable electronic devices to be smaller and used for longer periods of time has necessitated the need for high-capacity batteries. Furthermore, the widespread use of wearable electronic devices has also led to demands for battery safety. Consequently, the development of all-solid-state batteries, which use solid electrolytes instead of liquid electrolytes, is actively underway.

[0003] Since all-solid-state batteries do not use flammable organic solvents, additional safety circuits can be simplified. Therefore, all-solid-state batteries are expected to become a technology that can produce batteries with high capacity per unit volume and are safe.

[0004] In addition, compared with sulfide all-solid-state batteries that use sulfide electrolytes that react oxygen and moisture in the air, the use of sulfide electrolytes with ionic conductivity (10 -2 S / cm) low ionic conductivity (10 -4 S / cm to 10 -6 S / cm) oxide all-solid-state batteries require a high-temperature sintering process but exhibit excellent stability.

[0005] Stacked oxide all-solid-state batteries are miniature batteries and can therefore be mounted on a substrate like passive devices. Furthermore, they are stable even when exposed to high temperatures during the reflow process used for mounting.

[0006] Research is underway to apply stacked oxide all-solid-state batteries to various fields, and in particular, demand for all-solid-state batteries having excellent interface stability and excellent ion conductivity at the interface with the electrode is increasing. Summary of the Invention

[0007] Solutions to the Problem Various embodiments of the present disclosure are directed to providing an all-solid-state battery with excellent interfacial stability and lithium ion conductivity.

[0008] However, the problems to be solved by the embodiments are not limited to the above-mentioned problems, and various extensions can be made within the scope of the technical ideas included in the embodiments.

[0009] Advantageous Effects of the Invention By providing the all-solid-state battery according to various embodiments of the present disclosure, the interface stability between the electrode and the solid electrolyte is improved, and the ion conductivity is improved due to the densification.

[0010] However, various beneficial advantages and effects of the present disclosure are not limited to the above description and will be more easily understood in the course of describing specific embodiments of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a perspective view schematically showing an all-solid-state battery according to an embodiment.

[0012] Figure 2 is a cross-sectional view schematically showing an all-solid-state battery according to an embodiment.

[0013] Figure 3 is a schematic cross-sectional view of an all-solid-state battery according to another embodiment.

[0014] Figure 4 are ion-milled cross-sectional scanning electron microscopy (SEM) images of the first electrolyte layer (top) and the second electrolyte layer (bottom).

[0015] Best Mode for Carrying Out the Invention According to an embodiment, an all-solid-state battery includes a positive electrode layer and a negative electrode layer and a solid electrolyte layer between the positive electrode layer and the negative electrode layer, wherein the solid electrolyte layer includes a first electrolyte layer and a second electrolyte layer, the first electrolyte layer includes a glass ceramic electrolyte, the glass ceramic electrolyte contains lithium chloride (LiCl), and the second electrolyte layer is arranged on one surface or both surfaces of the first electrolyte layer and includes a lithium borosilicate-based electrolyte.

[0016] The second electrolyte layer may be provided between the positive electrode layer and the first electrolyte layer, or the second electrolyte layer may be provided between the negative electrode layer and the first electrolyte layer.

[0017] The glass-ceramic electrolyte may further include lithium chloroborate crystals.

[0018] The glass-ceramic electrolyte may further include lithium (Li) oxide, boron (B) oxide, silicon (Si) oxide, phosphorus (P) oxide, and germanium (Ge) oxide.

[0019] The glass ceramic electrolyte may include 35 mol % to 55 mol % of lithium (Li) oxide, 30 mol % to 50 mol % of boron (B) oxide, 5 mol % to 15 mol % of silicon (Si) oxide, 0.1 mol % to 5 mol % of phosphorus (P) oxide, 0.1 mol % to 5 mol % of germanium (Ge) oxide, and 0.5 mol % to 10 mol % of lithium chloride, based on the total amount of the glass ceramic electrolyte.

[0020] The lithium borosilicate-based electrolyte may include lithium (Li) oxide, silicon (Si) oxide, and boron (B) oxide.

[0021] The lithium borosilicate-based electrolyte may include 35 mol % to 65 mol % of lithium (Li) oxide, 5 mol % to 25 mol % of silicon (Si) oxide, and 30 mol % to 50 mol % of boron (B) oxide, based on the total amount of the lithium borosilicate-based electrolyte.

[0022] The lithium borosilicate-based electrolyte may further include additional oxides, including Na (sodium), Mg (magnesium), Al (aluminum), P (phosphorus), K (potassium), Ca (calcium), Ti (titanium), V (vanadium), Cr (chromium), Mn (manganese), Fe (iron), Co (cobalt), Ni (nickel), Cu (copper), Zn (zinc), Ga (gallium), Ge (germanium), Se (selenium), Rb (rubidium), S (sulfur), Y (yttrium), Zr (zirconium), Nb (niobium), Mo (molybdenum), Ag (silver), In (indium), Sn (tin), Sb (antimony), Cs (cesium), Ba (vanadium), Hf (hafnium), Ta (tantalum), W (tungsten), Pb (lead), Bi (bismuth), Au (gold), La (lanthanum), Nd (neodymium), Eu (europium), or combinations thereof.

[0023] The lithium borosilicate-based electrolyte may further include additives comprising LiF, LiCl, LiBr, LiI, Li3N, LiPON, Li2C2O4, Li2CO3, LiAlCl4, Li2O, Li2S, LiSO4, Li2SO4, Li3PO4, Li3VO4, Li4GeO4, Li2Si2O5, Li2SiO3, Li4SiO4, Li4ZrO4, LiMoO4, LiAlF4, Li3Ni2, LiBF4, LiCF3SO3, or combinations thereof.

[0024] A ratio of an average thickness of the first electrolyte layer to an average thickness of the second electrolyte layer may be 1:1 to 15:1.

[0025] The all-solid-state battery may further include an edge layer disposed on the solid electrolyte layer and laterally adjacent to an edge of the positive electrode layer or an edge of the negative electrode layer.

[0026] According to another embodiment, an all-solid-state battery includes a positive electrode layer and a negative electrode layer and a solid electrolyte layer between the positive electrode layer and the negative electrode, wherein the solid electrolyte layer includes a first electrolyte layer and a second electrolyte layer, the first electrolyte layer includes a glass ceramic electrolyte, the glass ceramic electrolyte contains lithium chloride (LiCl), the second electrolyte layer is arranged on a surface of the first electrolyte layer and includes a lithium borosilicate (LBSO)-based electrolyte, the first electrolyte layer is arranged between the negative electrode layer and the second electrolyte layer, and the second electrolyte layer is arranged between the positive electrode layer and the first electrolyte layer.

[0027] The glass-ceramic electrolyte may further include lithium chloroborate crystals.

[0028] The glass-ceramic electrolyte may further include lithium (Li) oxide, boron (B) oxide, silicon (Si) oxide, phosphorus (P) oxide, and germanium (Ge) oxide.

[0029] The glass ceramic electrolyte may include 35 mol % to 55 mol % of lithium (Li) oxide, 30 mol % to 50 mol % of boron (B) oxide, 5 mol % to 15 mol % of silicon (Si) oxide, 0.1 mol % to 5 mol % of phosphorus (P) oxide, 0.1 mol % to 5 mol % of germanium (Ge) oxide, and may include 0.5 mol % to 10 mol % of lithium chloride, based on the total amount of the glass ceramic electrolyte.

[0030] The lithium borosilicate-based electrolyte may include lithium (Li) oxide, silicon (Si) oxide, and boron (B) oxide.

[0031] The lithium borosilicate-based electrolyte may include 35 mol % to 65 mol % of lithium (Li) oxide, 5 mol % to 25 mol % of silicon (Si) oxide, and 30 mol % to 50 mol % of boron (B) oxide, based on the total amount of the lithium borosilicate-based electrolyte.

[0032] The lithium borosilicate-based electrolyte may further include additional oxides, including Na (sodium), Mg (magnesium), Al (aluminum), P (phosphorus), K (potassium), Ca (calcium), Ti (titanium), V (vanadium), Cr (chromium), Mn (manganese), Fe (iron), Co (cobalt), Ni (nickel), Cu (copper), Zn (zinc), Ga (gallium), Ge (germanium), Se (selenium), Rb (rubidium), S (sulfur), Y (yttrium), Zr (zirconium), Nb (niobium), Mo (molybdenum), Ag (silver), In (indium), Sn (tin), Sb (antimony), Cs (cesium), Ba (vanadium), Hf (hafnium), Ta (tantalum), W (tungsten), Pb (lead), Bi (bismuth), Au (gold), La (lanthanum), Nd (neodymium), Eu (europium), or combinations thereof.

[0033] The lithium borosilicate-based electrolyte may further include additives comprising LiF, LiCl, LiBr, LiI, Li3N, LiPON, Li2C2O4, Li2CO3, LiAlCl4, Li2O, Li2S, LiSO4, Li2SO4, Li3PO4, Li3VO4, Li4GeO4, Li2Si2O5, Li2SiO3, Li4SiO4, Li4ZrO4, LiMoO4, LiAlF4, Li3Ni2, LiBF4, LiCF3SO3, or combinations thereof.

[0034] A ratio of an average thickness of the first electrolyte layer to an average thickness of the second electrolyte layer may be 1:1 to 15:1.

[0035] The all-solid-state battery may further include an edge layer disposed on the solid electrolyte layer and laterally adjacent to an edge of the positive electrode layer or an edge of the negative electrode layer. DETAILED DESCRIPTION

[0036] Hereinafter, various embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily perform the embodiments of the present disclosure. The drawings and descriptions are considered to be illustrative rather than restrictive in nature. Throughout the specification, the same reference numerals represent the same elements. In addition, the drawings are provided only to allow easy understanding of the embodiments disclosed in this specification, and the drawings should not be interpreted as limiting the spirit disclosed in this specification, and it should be understood that the present disclosure includes all modifications, equivalents and alternatives without departing from the scope and spirit of the present disclosure. In addition, some of the constituent elements in the drawings are exaggerated, omitted or shown schematically, and the size of each constituent element does not fully reflect the actual size.

[0037] In addition, unless explicitly described to the contrary, the word “comprise” and variations such as “comprises” or “comprising”, will be understood to imply the inclusion of stated elements but not the exclusion of any other elements.

[0038] Throughout this specification, the term "stacking direction" refers to the direction in which components are stacked sequentially, or the "thickness direction" perpendicular to the major surface (main surface) of a sheet-like component. This corresponds to the T-axis in the drawings. Furthermore, the term "lateral direction" refers to the direction extending parallel to the major surface (main surface) or the "planar direction" from the edge of a sheet-like component. This corresponds to the L-axis in the drawings. Furthermore, the W-axis in the drawings may be referred to as the "width direction."

[0039] Hereinafter, various embodiments and modifications will be described in detail with reference to the accompanying drawings.

[0040] According to an embodiment, an all-solid-state battery includes a positive electrode layer, a negative electrode layer, and a solid electrolyte layer between the positive electrode layer and the negative electrode, wherein the solid electrolyte layer includes a first electrolyte layer and a second electrolyte layer, the first electrolyte layer includes a glass ceramic electrolyte, the glass ceramic electrolyte includes lithium chloride (LiCl), and the second electrolyte layer is arranged on one surface or both surfaces of the first electrolyte layer and includes a lithium borosilicate (LBSO)-based electrolyte.

[0041] According to another embodiment, an all-solid-state battery includes a positive electrode layer and a negative electrode layer and a solid electrolyte layer between the positive electrode layer and the negative electrode, wherein the solid electrolyte layer includes a first electrolyte layer and a second electrolyte layer, the first electrolyte layer includes a glass ceramic electrolyte, the glass ceramic electrolyte includes lithium chloride (LiCl), the second electrolyte layer is arranged on a surface of the first electrolyte layer and includes a lithium borosilicate (LBSO)-based electrolyte, the first electrolyte layer is arranged between the negative electrode layer and the second electrolyte layer, and the second electrolyte layer is arranged between the positive electrode layer and the first electrolyte layer.

[0042] Figure 1 is a perspective view schematically showing an all-solid-state battery according to an embodiment, Figure 2 is a cross-sectional view schematically showing an all-solid-state battery according to an embodiment, and Figure 3 is a schematic cross-sectional view of an all-solid-state battery according to another embodiment.

[0043] The all-solid-state battery 100 may have, for example, a substantially hexahedral shape.

[0044] The all-solid-state battery 100 according to the embodiment includes electrode layers 120 and 140 and a solid electrolyte layer 130 adjacent to the electrode layers 120 and 140 in the stacking direction. The electrode layers 120 and 140 include a positive electrode layer 120 and a negative electrode layer 140, and mainly include current collectors 123 and 143 and active material layers 121, 122, 141 and 142 coated on at least one surface of the current collectors 123 and 143.

[0045] The positive electrode layer 120 is formed by coating positive active material layers 121 and 122 on at least one surface of a positive current collector 123 , and the negative electrode layer 140 is formed by coating negative active material layers 141 and 142 on at least one surface of a negative current collector 143 .

[0046] For example, in the stacking direction, the lowermost electrode layer is formed by coating the positive electrode active material layer 122 on one surface of the positive electrode collector 123, and the uppermost electrode layer is formed by coating the negative electrode active material layer 141 on one surface of the negative electrode collector 143. In addition, the electrode layer between the uppermost end and the lowermost end is formed by coating the positive electrode active material layers 121 and 122 on both surfaces of the positive electrode collector 123, or forming the negative electrode active material layers 141 and 142 on both surfaces of the negative electrode collector 143.

[0047] The positive electrode active material layers 121 and 122 may include a positive electrode active material, and optionally, may include a solid electrolyte. In addition, the positive electrode active material layers 121 and 122 may optionally further include an additive such as a binder or a conductive agent.

[0048] For example, the positive electrode active material is not particularly limited as long as it can ensure sufficient capacity of the all-solid-state battery 100. For example, the positive electrode active material may include lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium iron phosphate, lithium manganese oxide, or a combination thereof.

[0049] For example, the positive electrode active material may be a compound represented by the following chemical formula: Li a A l-b M b D2 (where 0.90≤a≤1.8, 0≤b≤0.5); Li a E l-b M b O 2-c D c (where 0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); LiE 2- b M b O 4-c D c(where 0≤b≤0.5, 0≤c≤0.05); Li a Ni 1-b-c Co b M c D α (where 0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05, 0<α≤2); Li a Ni 1-b-c Co b M c O 2-α X α (where 0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05, 0<α<2); Li a Ni 1-b-c CO b M c O 2-α X2 (where 0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05, 0<α<2); Li a Ni 1-b-c Mn b M c D α (where 0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05, 0<α≤2); Li a Ni 1-b-c Mn b M c O 2-α X α (where 0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05, 0<α<2); Li a Ni 1-b-c Mn b M c O 2-α X2 (where 0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05, 0<α<2); Li a Ni b E c G d O2 (where 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 GeO2 (where 0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0.001≤e≤0.1); Li a NiGbO2 (where 0.90≤a≤1.8, 0.001≤b≤0.1); Lia CoGbO2 (where 0.90≤a≤1.8, 0.001≤b≤0.1); Li a MnGbO2 (where 0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn2GbO4 (where 0.90≤a≤1.8, 0.001≤b≤0.1); QO2; QS2; LiQS2; V2O5; LiV2O2; LiRO2; LiNiVO4; Li (3-f) J2(PO4)3(0≤f≤2);Li (3-f) Fe2(PO4)3 (wherein 0≤f≤2); and LiFePO4, wherein, in the above chemical formula, A is Ni, Co or Mn; M is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V or a rare earth element; D is O, F, S or P; E is Co or Mn; X is F, S or P; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr or V; Q is Ti, Mo or Mn; R is Cr, V, Fe, Sc or Y; and J is V, Cr, Mn, Co, Ni or Cu.

[0050] The positive electrode active material can also be LiCoO2, LiMn x O 2x (where x = 1 or 2), LiNi 1-x Mn x O 2x (where 0<x<1), LiNi 1-x-y Co x Mn y O2 (wherein, 0≤x≤0.5, 0≤y≤0.5), LiFePO4, TiS2, FeS2, TiS3 or FeS3.

[0051] As the solid electrolyte, a solid electrolyte (described later) that can be used in the solid electrolyte layer 130 can be used. The solid electrolyte can function as an ion conduction path in the positive electrode layer 120, and thereby reduce interface resistance.

[0052] The content of the solid electrolyte may be greater than or equal to 0.1 parts by weight, greater than or equal to 1 part by weight, or greater than or equal to 10 parts by weight, and less than or equal to 80 parts by weight, less than or equal to 60 parts by weight, or less than or equal to 50 parts by weight based on 100 parts by weight of the total amount of the positive electrode active material.

[0053] The conductive agent is not particularly limited as long as it has conductivity without causing chemical changes in the all-solid-state battery 100. Examples of the conductive agent include: graphite, such as natural graphite and artificial graphite; carbon-based substances, such as carbon black, acetylene black, Ketjen black, channel black, furnace black, lamp black, and thermal black; conductive fibers, such as carbon fibers and metal fibers; carbon fluoride; metal powders, such as aluminum powder and nickel powder; conductive whiskers, such as zinc oxide and potassium titanate; conductive metal oxides, such as titanium oxide; or conductive materials, such as polyphenylene derivatives.

[0054] The conductive agent may be present in an amount of 1 to 10 parts by weight, or 2 to 5 parts by weight, based on 100 parts by weight of the positive electrode active material.

[0055] Binders can be used to improve the bond strength between the active material and the conductive agent. Binders can include polyvinylidene fluoride, polyvinyl alcohol, carboxymethyl cellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinyl pyrrolidone, polytetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene-butadiene rubber, fluororubber, acrylic resins, or various copolymers.

[0056] The binder may be present in an amount of 1 to 50 parts by weight, or 2 to 5 parts by weight, based on 100 parts by weight of the total positive active material.

[0057] Porous materials such as a network or mesh can be used as the positive electrode collector 123. A porous metal plate such as stainless steel, nickel, or aluminum can be used. The positive electrode collector 123 may be coated with an oxidation-resistant metal film or alloy film to prevent oxidation.

[0058] The negative electrode active material layers 141 and 142 may include a negative electrode active material, and optionally, may include a solid electrolyte. In addition, the negative electrode active material layers 141 and 142 may further include an additive such as a binder or a conductive agent.

[0059] The negative electrode active material may be a carbon-based material, silicon, silicon oxide, silicon-based alloy, silicon-carbon-based material composite, tin, tin-based alloy, tin-carbon composite, metal oxide, or a combination thereof, and may include lithium metal and / or lithium metal alloy.

[0060] The lithium metal alloy may include lithium and a metal / semimetal capable of alloying with lithium. For example, the metal / semimetal capable of alloying with lithium may include Si, Sn, Al, Ge, Pb, Bi, Sb, Si-Y alloy (where Y is an alkali metal, alkaline earth metal, Group 13 to Group 16 element, transition metal, rare earth element or a combination thereof, and does not include Si), Sn-Y alloy (where Y is an alkali metal, alkaline earth metal, Group 13 to Group 16 element, transition metal, transition metal oxide such as lithium titanate (Li4Ti5O 12 ), rare earth element or a combination thereof, and does not include Sn) or MnO x (0 < x ≤ 2).

[0061] 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, Tl, Ge, P, As, Sb, Bi, S, Se, Te, Po or a combination thereof.

[0062] In addition, the oxide of the metal / semimetal capable of alloying with lithium may be lithium titanate, vanadium oxide, lithium vanadium oxide, SnO2, SiO x (0 < x < 2), etc. For example, the negative electrode active material may include one or more elements selected from the elements of Group 13 to Group 16 of the periodic table. For example, the negative electrode active material may include one or more elements selected from the group consisting of Si, Ge, and Sn.

[0063] The carbon-based material may be crystalline carbon, amorphous carbon or a mixture thereof. The crystalline carbon may include: graphite, such as natural graphite or artificial graphite in irregular, plate-like, flaky, spherical or fibrous forms. In addition, the amorphous carbon may include soft carbon (low-temperature calcined carbon) or hard carbon, mesophase pitch carbonization products, calcined coke, graphene, carbon black, fullerene soot, carbon nanotubes, carbon fibers, etc.

[0064] Silicon may be Si, SiO x (0 < x < 2, for example 0.5 to 1.5), Sn, SnO2, a silicon-containing metal alloy or a mixture thereof. For example, the silicon-containing metal alloy may include one or more of Al, Sn, Ag, Fe, Bi, Mg, Zn, in, Ge, Pb, and Ti and silicon.

[0065] As the solid electrolyte, a solid electrolyte (described later) that can be used in the solid electrolyte layer 130 can be used. The solid electrolyte can function as an ion conduction path in the negative electrode layer 140 and, in this way, can reduce interface resistance.

[0066] The solid electrolyte may be present in an amount of 0.1 parts by weight, 1 part by weight, or 10 parts by weight, and 80 parts by weight, 60 parts by weight, or 50 parts by weight or less based on 100 parts by weight of the total amount of the negative electrode active material.

[0067] Optionally, the negative active material layers 141 and 142 may further include a conductive agent and a binder as described with respect to the positive active material layers 121 and 122 .

[0068] As the negative electrode current collector 143, a porous material such as a network or mesh can be used, and a porous metal plate such as stainless steel, nickel, or aluminum can be used. In addition, the negative electrode current collector 143 can be coated with a metal film or alloy film having oxidation resistance to prevent oxidation.

[0069] The solid electrolyte layer 130 may be disposed and stacked between the positive electrode layer 120 and the negative electrode layer 140. Therefore, the solid electrolyte layer 130 may be adjacently disposed between the positive electrode active material layers 121 and 122 of the positive electrode layer 120 and the negative electrode active material layers 141 and 142 of the negative electrode layer 140 in the stacking direction.

[0070] Therefore, in the all-solid-state battery 100, multiple positive electrode layers 120 and multiple negative electrode layers 140 can be alternately arranged, and multiple solid electrolyte layers 130 can be interposed and stacked between them. In the all-solid-state battery 100, multiple positive electrode layers 120 and multiple negative electrode layers 140 are alternately stacked with multiple solid electrolyte layers 130 interposed therebetween to produce a battery stack, which can then be batch-fired to produce a stacked all-solid-state battery 100.

[0071] Reference Figure 2 In an embodiment, the solid electrolyte layer 130 includes a first electrolyte layer 131 and a second electrolyte layer 132 provided on one surface or both surfaces of the first electrolyte layer 131 .

[0072] For example, the second electrolyte layer 132 may be disposed between the electrode layers 120 and 140 and the first electrolyte layer 131 , for example, the second electrolyte layer 132 may be disposed between the positive electrode layer 120 and the first electrolyte layer 131 and / or between the negative electrode layer 140 and the first electrolyte layer 131 .

[0073] For example, the second electrolyte layer 132 may be provided in contact with the positive electrode active material layers 121 and 122, and the second electrolyte layer 132 may be provided in contact with the negative electrode active material layers 141 and 142. In other words, the second electrolyte layer 132 may directly contact the electrode active material layers 121, 122, 141, and 142, and the first electrolyte layer 131 may not directly contact the electrode active material layers 121, 122, 141, and 142 but may be located between the second electrolyte layers 132.

[0074] Reference Figure 3 The solid electrolyte layer 130 according to another embodiment includes a first electrolyte layer 131 and a second electrolyte layer 132 , and the second electrolyte layer 132 is provided on one surface of the first electrolyte layer 131 .

[0075] For example, the first electrolyte layer 131 is disposed between the negative electrode layer 140 and the second electrolyte layer 132 , and the second electrolyte layer 132 may be disposed between the positive electrode layer 120 and the first electrolyte layer 131 .

[0076] For example, the second electrolyte layer 132 may be provided in contact with the positive electrode active material layers 121 and 122, and the first electrolyte layer 131 may be provided in contact with the negative electrode active material layers 141 and 142. In other words, the first electrolyte layer 131 may directly contact the negative electrode active material layers 141 and 142, and the second electrolyte layer 132 may directly contact the positive electrode active material layers 121 and 122.

[0077] In an embodiment, the first electrolyte layer 131 may have an average thickness of 5 μm to 30 μm, for example, 10 μm to 30 μm or 15 μm to 20 μm.

[0078] The average thickness of the second electrolyte layer 132 may be 1 μm to 10 μm, for example, 2 μm to 7 μm or 2 μm to 5 μm.

[0079] In an embodiment, a ratio of an average thickness of the first electrolyte layer 131 to an average thickness of the second electrolyte layer 132 may be 1:1 to 15:1, eg, 3:1 to 10:1 or 3:1 to 7:1.

[0080] When the average thickness of the first electrolyte layer 131 and the second electrolyte layer 132 satisfies the range, an all-solid-state battery having excellent ion conductivity and excellent interface stability may be realized.

[0081] The average thickness of the first electrolyte layer 131 and the average thickness of the second electrolyte layer 132 can be measured according to the following method. Cross-sections of the first electrolyte layer 131 and the second electrolyte layer 132 are obtained by ion milling or the like, and scanning electron microscope (SEM) photographs thereof are acquired. Subsequently, in the cross-section SEM photographs, ten points are randomly selected and the thicknesses of the respective layers are measured, and the arithmetic mean of the measurement results is calculated, and the arithmetic mean is obtained as the average thickness of the first electrolyte layer 131 and the average thickness of the second electrolyte layer 132.

[0082] The solid electrolyte layer 130 may include an inorganic solid electrolyte, and the inorganic solid electrolyte includes an oxide-based solid electrolyte, a sulfide-based solid electrolyte, or a combination thereof.

[0083] The oxide-based solid electrolyte may be a garnet-type electrolyte, a sodium superionic conductor (NASICON)-type electrolyte, a lithium superionic conductor (LISICON)-type electrolyte, a perovskite-type electrolyte, a LiPON-type electrolyte, or an amorphous (glass) electrolyte.

[0084] The garnet-type solid electrolyte may include: lithium-lanthanum-zirconium oxide (LLZO) represented by Li a La b Zr c O 12 (such as Li7La3Zr2O 12 ), and the NASICON-type solid electrolyte may include: lithium-aluminum-titanium-phosphate (LATP)-type compounds in which Ti is introduced into Li 1+x Al x M 2-x (PO4)3 (LAMP) (0 < x < 2, M is Zr, Ti, or Ge) of Li 1+x Al x Ti 2-x (PO4)3 (0 < x < 1); lithium-aluminum-germanium-phosphate (LAGP) represented by Li 1+x Al x Ge 2-x (PO4)3 (0 < x < 1), such as Li introduced with an excess of Li 1.3 Al 0.3 Ti 1.7 (PO4)3; and / or lithium-zirconium-phosphate (LZP) of LiZr2(PO4)3.

[0085] In addition, the LISICON-type solid electrolyte may include: a solid solution oxide represented by xLi3AO4-(1-x)Li4BO4 (where A is P, As, or V and B is Si, Ge, or Ti), such as Li4Zn(GeO4)4, Li 10 GeP2O12 (LGPO), Li 3.5 Si 0.5 P 0.5 O4 or Li 10.42 Si(Ge) 1.5 P 1.5 Cl 0.08 O 11.92 , or a solid - solution sulfide represented by Li 4-x M 1-y M' y S4 (where M is Si or Ge and M' is P, Al, Zn, or Ga), such as Li2S - P2S5, Li2S - SiS2, Li2S - SiS2 - P2S5, or Li2S - GeS2.

[0086] The perovskite - type solid electrolyte may include lithium lanthanum titanate (LLTO) represented by Li 3x La 2 / 3-x □ 1 / 3-2x TiO3 (0 < x < 0.16, □: vacancy), such as Li 1 / 8 La 5 / 8 TiO3. The LiPON - type solid electrolyte may include lithium phosphorus oxynitride, such as Li 2.8 PO 3.3 N 0.46 .

[0087] Examples of amorphous electrolytes include Li2O - B2O3 - SiO2, Li2O - B2O3 - P2O5, Li3BO3 - Li2SO4, or Li3BO3 - Li2CO3.

[0088] The lithium - ion conductivity of the oxide - type solid electrolyte included in the solid electrolyte layer 130 may be greater than or equal to 1×10 -5 S / cm. The ion conductivity may be measured at a temperature of 25°C. The ion conductivity may be greater than or equal to 1×10 -5 S / cm, greater than or equal to 2×10 -5 S / cm, greater than or equal to 3×10 -5 S / cm, greater than or equal to 4×10 -5 S / cm, or greater than or equal to 5×10 -5 S / cm, and its upper limit is not particularly limited. When using a solid electrolyte with an ion conductivity satisfying the above range, the all - solid - state battery 100 may exhibit high power. <000​​​​In an embodiment, the first electrolyte layer 131 includes a glass-ceramic electrolyte including lithium chloride (LiCl), and the second electrolyte layer 132 includes a lithium borosilicate (LBSO)-based electrolyte.

[0091] First electrolyte layer 131 includes a glass-ceramic electrolyte containing lithium chloride (LiCl). Glass-ceramic (or crystallized glass) refers to the observation of peaks and halos in X-ray diffraction or electron beam diffraction, indicating the coexistence of amorphous and crystalline materials. Therefore, the glass-ceramic electrolyte partially crystallizes upon firing, resulting in a mixed state of amorphous and crystalline materials.

[0092] When a glass-ceramic electrolyte is included, densification is sufficiently ensured after firing, achieving high ionic conductivity. In contrast, when a glass-ceramic electrolyte is provided at the interface with an electrode, the glass-ceramic electrolyte may react with the electrode and form a second phase, and short circuits may occur due to interlayer migration of the electrode material.

[0093] Reference Figure 2 In an embodiment, the first electrolyte layer 131 including a glass ceramic electrolyte is disposed between the second electrolyte layers 132 without directly contacting the electrode active material layers 121 , 122 , 141 , and 142 , improving interface stability and achieving excellent ion conductivity.

[0094] Reference Figure 3 In another example embodiment, the first electrolyte layer 131 including a glass-ceramic electrolyte may be provided to directly contact only the negative electrode active material layers 141 and 142, and not to directly contact the positive electrode active material layers 121 and 122. In other words, when the positive electrode active material layer directly contacts the solid electrolyte layer, since lithium ions diffuse from the solid electrolyte layer to the positive electrode active material layer and cause a greater interfacial reaction than at the negative electrode, the first electrolyte layer 131 including a glass-ceramic electrolyte may be introduced only at the interface contacting the negative electrode.

[0095] The glass-ceramic electrolyte may include lithium (Li) oxide, boron (B) oxide, silicon (Si) oxide, phosphorus (P) oxide, germanium (Ge) oxide, and lithium chloride (LiCl).

[0096] As a specific example, the glass-ceramic electrolyte may include Li2O-B2O3-SiO2-P2O5-GeO2-LiCl. For example, the glass-ceramic electrolyte may include a crystalline phase of lithium chloroborate.

[0097] Lithium oxide (Li2O) may be included in an amount of 35 mol% to 55 mol% (e.g., 40 mol% to 50 mol%) based on the total amount of the glass-ceramic electrolyte. When the content of lithium oxide is less than 35 mol%, lithium ion conductivity may be low, and when the content of lithium oxide exceeds 55 mol%, vitrification may be difficult and deliquescent properties may be deteriorated.

[0098] Boron oxide (BO) may be included in an amount of 30 mol% to 50 mol% (e.g., 30 mol% to 40 mol%) based on the total amount of the glass-ceramic electrolyte. When the content of boron oxide is less than 30 mol%, ion conductivity may be degraded, but when the content of boron oxide is greater than 50 mol%, the all-solid-state battery may be easily affected when exposed to a high humidity environment.

[0099] Silicon oxide (SiO2) may be included in an amount of 5 mol% to 15 mol% (e.g., 10 mol% to 15 mol%) based on the total amount of the glass-ceramic electrolyte. When the content of silicon oxide is less than 5 mol%, the all-solid-state battery may be easily affected by exposure to a high humidity environment, but when the content of silicon oxide is greater than 15 mol%, ionic conductivity may deteriorate.

[0100] Phosphorus oxide (P2O5) may be included in an amount of 0.1 mol% to 5 mol% (e.g., 0.5 mol% to 2.5 mol%) based on the total amount of the glass-ceramic electrolyte. When the content of phosphorus oxide is less than 0.1 mol%, the material density may be reduced, but when the content of phosphorus oxide is greater than 5 mol%, ion conductivity may be degraded.

[0101] Germanium oxide (GeO2) may be included in an amount of 0.1 mol% to 5 mol% (e.g., 1 mol% to 5 mol%) based on the total amount of the glass-ceramic electrolyte. When the content of germanium oxide is less than 0.1 mol%, the material density may be reduced, but when the content of germanium oxide is greater than 5 mol%, ion conductivity may be degraded.

[0102] Lithium chloride (LiCl) may be included in an amount of 0.5 mol% to 10 mol% (e.g., 2 mol% to 8 mol%) based on the total amount of the glass-ceramic electrolyte. When the content of lithium chloride is less than 0.5 mol%, lithium ion conductivity may be deteriorated, while when the content of lithium chloride is 10 mol%, deliquescent properties may be deteriorated.

[0103] The content of each component described above is the content of each component in the glass-ceramic electrolyte, and is expressed as a percentage (mol%) by, for example, the ratio of the content (mol) of each component to the total mole of lithium (Li) oxide, boron (B) oxide, silicon (Si) oxide, phosphorus (P) oxide, germanium (Ge) oxide, and lithium chloride (LiCl). The content of each component can be measured using inductively coupled plasma atomic emission spectrometry (ICP-AES) or the like.

[0104] Second electrolyte layer 132 includes a lithium borosilicate-based electrolyte (hereinafter, LBSO-type solid electrolyte). LBSO-type solid electrolyte is a glassy electrolyte, and glass is crystallographically amorphous, which exhibits peaks in X-ray diffraction, electron beam diffraction, and the like.

[0105] The inclusion of an LBSO-type solid electrolyte offers the advantage of achieving high ionic conductivity without high reactivity with electrodes, as the firing temperature can be lowered and the amorphous state can be maintained during firing. However, under firing conditions that maintain the amorphous state, sufficient densification cannot be achieved, making it difficult to improve ionic conductivity.

[0106] Reference Figure 2 In an embodiment, second electrolyte layer 132 including an LBSO-type solid electrolyte may be provided in direct contact with electrode active material layers 121, 122, 141, and 142 to ensure interfacial stability. Furthermore, as described above, the above-mentioned problem can be solved by providing first electrolyte layer 131, which is sufficiently dense and capable of achieving high ionic conductivity, between second electrolyte layer 132.

[0107] Reference Figure 3 In another exemplary embodiment, the second electrolyte layer 132 including an LBSO-type solid electrolyte is provided so as to directly contact only the positive electrode active material layers 121 and 122, and not directly contact the negative electrode active material layers 141 and 142. In other words, when the positive electrode active material layer and the solid electrolyte layer are in direct contact with each other, since lithium ions diffuse from the solid electrolyte layer to the positive electrode active material layer and there is a greater interfacial reaction than at the negative electrode, the second electrolyte layer 132 including the LBSO-type solid electrolyte can be introduced only at the interface contacting the positive electrode.

[0108] The LBSO type solid electrolyte may include lithium (Li) oxide, silicon (Si) oxide, and boron (B) oxide. For example, the LBSO type solid electrolyte may include Li2O-SiO2-B2O3.

[0109] Lithium oxide (Li2O) may be included in an amount of 35 mol% to 65 mol% (e.g., 40 mol% to 60 mol% or 45 mol% to 55 mol%) based on the total amount of the LBSO-type solid electrolyte. When the content of the lithium oxide is less than 35 mol%, lithium ion conductivity may be low, and when the content of the lithium oxide exceeds 65 mol%, vitrification may be difficult and deliquescent properties may be deteriorated.

[0110] Silicon oxide (SiO2) may be included in an amount of 5 mol% to 25 mol% (e.g., 10 mol% to 20 mol%) based on the total amount of the LBSO-type solid electrolyte. When the content of silicon oxide is less than 5 mol%, the all-solid-state battery may be easily affected by exposure to a high humidity environment, but when the content of silicon oxide is greater than 25 mol%, ionic conductivity may deteriorate.

[0111] Boron oxide (BO) is included in an amount of 30 mol% to 50 mol% (e.g., 30 mol% to 40 mol%) based on the total amount of the LBSO-type solid electrolyte. When the content of boron oxide is less than 30 mol%, ion conductivity may deteriorate, but when the content of boron oxide is greater than 50 mol%, the all-solid-state battery may be easily affected by exposure to a high humidity environment.

[0112] Optionally, the LBSO-type solid electrolyte further includes an additional oxide, which includes Na (sodium), Mg (magnesium), Al (aluminum), P (phosphorus), K (potassium), Ca (calcium), Ti (titanium), V (vanadium), Cr (chromium), Mn (manganese), Fe (iron), Co (cobalt), Ni (nickel), Cu (copper), Zn (zinc), Ga (gallium), Ge (germanium), Se (selenium), Rb (rubidium), S (sulfur), Y (yttrium), Zr (zirconium), Nb (niobium), Mo (molybdenum), Ag (silver), In (indium), Sn (tin), Sb (antimony), Cs (cesium), Ba (vanadium), Hf (hafnium), Ta (tantalum), W (tungsten), Pb (lead), Bi (bismuth), Au (gold), La (lanthanum), Nd (neodymium), Eu (europium), or a combination thereof.

[0113] In this case, when the additional oxide is further included, the additional oxide may be included in an amount of 0 mol % to 10 mol % based on the total amount of the LBSO-type solid electrolyte.

[0114] The LBSO-type solid electrolyte may further include an additive, and the additive may include LiF, LiCl, LiBr, LiI, Li3N, LiPON, Li2C2O4, Li2CO3, LiAlCl4, Li2O, Li2S, LiSO4, Li2SO4, Li3PO4, Li3VO4, Li4GeO4, Li2Si2O5, Li2SiO3, Li4SiO4, Li4ZrO4, LiMoO4, LiAlF4, Li3Ni2, LiBF4, LiCF3SO3, or a combination thereof, and in terms of achieving high ionic conductivity, may include LiCl or LiSO4.

[0115] In terms of improving the performance of the all-solid-state battery 100, the solid electrolyte layer 130 may have a thickness greater than or equal to 1×10 - 6 S / cm lithium ion conductivity. The ion conductivity can be measured at a temperature of 25 ° C. The ion conductivity can be greater than or equal to 1×10 - 6 S / cm, greater than or equal to 2×10 -6 S / cm, greater than or equal to 3×10 -6 S / cm, greater than or equal to 4×10 -6 S / cm, or greater than or equal to 5×10 -6 S / cm, and the upper limit thereof is not particularly limited.

[0116] The lithium (Li) ion conductivity of the solid electrolyte layer 130 can be measured by the alternating current (AC) impedance method. First, a portion of the solid electrolyte layer 130 in the all-solid-state battery 100 is sampled into a rectangular plate-like piece by ion milling or polishing. Subsequently, electrodes made of gold (Au) are formed on both ends of the obtained piece to prepare a sample. Then, an impedance measurement device (frequency: 10 +6 Hz to 10 -1 The AC impedance of the samples was measured at room temperature (25 °C) to calculate the ionic conductivity.

[0117] In an embodiment, the edge layer 150 may be provided along the edges of the positive electrode layer 120 and the negative electrode layer 140. The edge layer 150 is provided on the solid electrolyte layer 130 and may be formed to be laterally adjacent to the edges of the positive electrode active material layers 121 and 122 or the edges of the negative electrode active material layers 141 and 142. Therefore, the edge layer 150 may be provided on the same layer as the positive electrode layer 120 and on the same layer as the negative electrode layer 140.

[0118] The edge layer 150 may include a layer having a thickness less than or equal to 1.0×10 -10 S / cm or less than or equal to 1.0×10 -6An insulating material having an ion conductivity of 0.1 S / cm, for example, an insulating material such as the aforementioned solid electrolyte material, ceramic or resin.

[0119] For example, the ceramic may include aluminum oxide (Al2O3), aluminum nitride (AlN), beryllium oxide (BeO), boron nitride (BN), silicon (Si), silicon carbide (SiC), silicon dioxide (SiO2), silicon nitride (Si3N4), gallium arsenide (GaAs), gallium nitride (GaN), barium titanate (BaTiO3), zirconium dioxide (ZrO2), mixtures thereof, oxides and / or nitrides of these materials.

[0120] For example, the resin may be polyolefin (such as polyethylene or polypropylene), polyester (such as polyethylene terephthalate (PET)), polyurethane, or polyimide.

[0121] In addition, the edge layer 150 may include an inorganic solid electrolyte including an oxide-type solid electrolyte, a sulfide-type solid electrolyte, or a combination thereof used in the solid electrolyte layer 130. However, the edge layer 150 is not limited thereto but may include various materials.

[0122] The positive electrode layer 120, the solid electrolyte layer 130, the negative electrode layer 140, and the edge layer 150 may be stacked as described above to constitute a battery stack of the all-solid-state battery 100. Cover layers 160 may be further provided on the upper and lower ends of the battery stack of the all-solid-state battery 100.

[0123] For example, the cover layer 160 may be provided on the outer surfaces of the uppermost electrode layer and the lowermost electrode layer in the stacking direction of the battery stack. In this case, a solid electrolyte layer may be provided between the cover layer and the electrode layer adjacent to the cover layer.

[0124] In order to impart insulation and moisture-proof functions to the all-solid-state battery 100, the cover layer 160 may include, for example, the same material as the edge layer 150, for example, an insulating material such as the aforementioned solid electrolyte material, ceramic, or resin. Since it has been described above, a detailed description thereof will be omitted.

[0125] In addition, the terminals of the positive electrode collector 123 and the negative electrode collector 143 are exposed on both sides of the battery stack of the all-solid-state battery 100, and the external electrodes 112 and 114 can be connected to and bonded to the exposed terminals. That is, the external electrodes 112 and 114 can be arranged to have positive polarity by being connected to the terminals of the positive electrode collector 123, and to have negative polarity by being connected to the terminals of the negative electrode collector 143. When the terminals of the positive electrode collector 123 and the negative electrode collector 143 are arranged to face opposite directions, the external electrodes 112 and 114 can also be arranged on both sides, respectively.

[0126] The external electrodes 112 and 114 may include conductive metal and glass.

[0127] The conductive metal may include, for example, copper (Cu), nickel (Ni), tin (Sn), palladium (Pd), platinum (Pt), gold (Au), silver (Ag), tungsten (W), titanium (Ti), lead (Pb), or alloys thereof.

[0128] The glass component included in the external electrodes 112 and 114 may have a composition in which an oxide is mixed. The glass component may include, for example, silicon oxide, boron oxide, aluminum oxide, transition metal oxide, alkali metal oxide, alkaline earth metal oxide, or a combination thereof. Here, the transition metal may be selected from zinc (Zn), titanium (Ti), copper (Cu), vanadium (V), manganese (Mn), iron (Fe), or nickel (Ni), the alkali metal may be selected from lithium (Li), sodium (Na), or potassium (K), and the alkaline earth metal may be selected from magnesium (Mg), calcium (Ca), strontium (Sr), or barium (Ba).

[0129] The method for forming the external electrodes 112 and 114 is not particularly limited. For example, the method may include immersing the battery stack in a conductive paste containing a conductive metal and glass, or screen printing or gravure printing the conductive paste on the surface of the battery stack. Alternatively, various methods may be used, such as applying the conductive paste to the surface of the battery stack or transferring a dry film obtained by drying the conductive paste onto the battery stack.

[0130] According to an embodiment, a stacked all-solid-state battery includes a battery stack and a first outer electrode and a second outer electrode, the battery stack includes multiple solid electrolyte layers and multiple positive electrode layers and multiple negative electrode layers, the multiple positive electrode layers and the multiple negative electrode layers are alternately arranged with multiple solid electrolyte layers between them, the first outer electrode and the second outer electrode are arranged to be adjacent to the battery stack in the lateral direction and are respectively connected to the multiple positive electrode layers and the multiple negative electrode layers, wherein the solid electrolyte layer may include a first electrolyte layer and a second electrolyte layer, the first electrolyte layer includes a glass ceramic electrolyte, the glass ceramic electrolyte includes lithium chloride (LiCl), and the second electrolyte layer is arranged on one surface or both surfaces of the first electrolyte layer and includes a lithium borosilicate-based electrolyte.

[0131] According to another embodiment, a stacked all-solid-state battery includes a battery stack and a first outer electrode and a second outer electrode, the battery stack including a plurality of solid electrolyte layers and a plurality of positive electrode layers and a plurality of negative electrode layers, the plurality of positive electrode layers and the plurality of negative electrode layers being alternately arranged with the plurality of solid electrolyte layers interposed therebetween, the first outer electrode and the second outer electrode being arranged to be laterally adjacent to the battery stack and being connected to the plurality of positive electrode layers and the plurality of negative electrode layers, respectively, wherein the solid electrolyte layer may include a first electrolyte layer and a second electrolyte layer, the first electrolyte layer including a glass-ceramic electrolyte including lithium chloride (LiCl), the second electrolyte layer being arranged on a surface of the first electrolyte layer and including a lithium borosilicate (LBSO)-based electrolyte, the first electrolyte layer being arranged between the negative electrode layer and the second electrolyte layer, and the second electrolyte layer being arranged between the positive electrode layer and the first electrolyte layer.

[0132] Hereinafter, specific examples of the present disclosure are presented. However, the examples described below are only intended to specifically illustrate or explain the inventive concept of the present disclosure, and the scope of the present disclosure should not be limited thereto.

[0133] (Example 1) A first electrolyte layer green sheet was manufactured to include 43 mol % of Li 2 O, 37 mol % of B 2 O 3 , 11 mol % of SiO 2 , 1 mol % of P 2 O 5 , 3 mol % of GeO 2 , and 5 mol % of LiCl.

[0134] A second electrolyte layer green sheet was produced to also include 50 mol % of Li 2 O, 17 mol % of SiO 2 , and 33 mol % of B 2 O 3 .

[0135] From the bottom, [positive electrode layer green sheet - second electrolyte layer green sheet - first electrolyte layer green sheet - second electrolyte layer green sheet - negative electrode layer green sheet] were stacked in this order and then fired at 510° C. to produce a unit cell.

[0136] (Example 2) A unit cell was manufactured in the same manner as in Example 1 except that [positive electrode layer green sheet-second electrolyte layer green sheet-first electrolyte layer green sheet-negative electrode layer green sheet-first electrolyte layer green sheet-second electrolyte layer green sheet-positive electrode layer green sheet] was stacked in this order from the bottom.

[0137] (Comparative Example 1: Single LBSO Electrolyte Layer) A unit cell was manufactured in the same manner as in Example 1 except that [positive electrode layer green sheet - second electrolyte layer green sheet - negative electrode layer green sheet] were stacked in this order from the bottom.

[0138] (Comparative Example 2: Single LCB Electrolyte Layer) A unit cell was manufactured in the same manner as in Example 1 except that [positive electrode layer green sheet - first electrolyte layer green sheet - negative electrode layer green sheet] were stacked in this order from the bottom.

[0139] (Experimental example: Analysis of lithium ion conductivity at room temperature) Each unit cell of Examples 1 and 2 and Comparative Examples 1 and 2 was ion milled, and a portion of each solid electrolyte layer was sampled into a rectangular plate-like piece. Electrodes made of gold (Au) were formed at both ends of the piece to prepare a sample. Subsequently, the impedance was measured using an impedance measurement device (frequency: 10 +6 Hz to 10 -1 The AC impedance of the samples was measured at room temperature (25°C) using a flow rate of 100 mV (1000 mV) and a voltage of 100 mV (1000 mV). The ionic conductivity was calculated. The calculated results are shown in Table 1.

[0140] [Table 1]

[0141] Referring to Table 1, the examples achieve high ionic conductivity by maintaining an amorphous state during firing. These examples achieve ionic conductivity of E-06 (S / cm) or higher by providing a second electrolyte layer that is not highly reactive with the electrode at the interface with the electrode layer (Example 1) or a second electrolyte layer that is not highly reactive with the electrode at the interface with the positive electrode layer (Example 2), and by providing a first electrolyte layer that is highly reactive with the interface so as not to face the electrode layer (Example 1) or only to face the negative electrode layer (Example 2). On the other hand, the comparative examples include a solid electrolyte layer consisting of a single layer and therefore exhibit low ionic conductivity due to insufficient densification (Comparative Example 1) or due to the generation of a second phase through reaction at the electrode interface (Comparative Example 2).

[0142] While the inventive concept of the present disclosure has been described in conjunction with what are presently considered to be practical example embodiments, it is to be understood that the disclosure is not limited to the disclosed embodiments, but is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

[0143] Industrial Applicability The present disclosure relates to an all-solid-state battery having excellent interface stability between an electrode and a solid electrolyte, excellent ionic conductivity by achieving densification, and can be used in various electrochemical devices and electronic devices.

[0144] <Description of Reference Signs> 100: All-solid-state battery 112, 114: External electrodes 120: positive electrode layer 121, 122: Positive electrode active material layer 123: Positive electrode current collector 130: Solid electrolyte layer 131: First electrolyte layer 132: Second electrolyte layer 140: Negative electrode layer 141, 142: Negative electrode active material layer 143: Negative electrode current collector 150: Edge layer 160: Overlay

Claims

1. An all-solid-state battery, comprising: a positive electrode layer, a negative electrode layer, and a solid electrolyte layer interposed between the positive electrode layer and the negative electrode layer, The solid electrolyte layer includes a first electrolyte layer and a second electrolyte layer, the first electrolyte layer includes a glass ceramic electrolyte, the glass ceramic electrolyte includes lithium chloride (LiCl), and the second electrolyte layer is arranged on one surface or both surfaces of the first electrolyte layer and includes a lithium borosilicate-based electrolyte.

2. The all-solid-state battery according to claim 1, wherein: The second electrolyte layer is provided between the positive electrode layer and the first electrolyte layer, or The second electrolyte layer is provided between the negative electrode layer and the first electrolyte layer.

3. The all-solid-state battery according to claim 1, wherein: The glass-ceramic electrolyte further includes lithium chloroborate crystals.

4. The all-solid-state battery according to claim 1, wherein: The glass-ceramic electrolyte further includes lithium (Li) oxide, boron (B) oxide, silicon (Si) oxide, phosphorus (P) oxide, and germanium (Ge) oxide.

5. The all-solid-state battery according to claim 4, wherein: The glass ceramic electrolyte includes 35 mol % to 55 mol % of lithium (Li) oxide, 30 mol % to 50 mol % of boron (B) oxide, 5 mol % to 15 mol % of silicon (Si) oxide, 0.1 mol % to 5 mol % of phosphorus (P) oxide, 0.1 mol % to 5 mol % of germanium (Ge) oxide, and 0.5 mol % to 10 mol % of lithium chloride, based on the total amount of the glass ceramic electrolyte.

6. The all-solid-state battery according to claim 1, wherein: The lithium borosilicate-based electrolyte includes lithium (Li) oxide, silicon (Si) oxide, and boron (B) oxide.

7. The all-solid-state battery according to claim 6, wherein: The lithium borosilicate-based electrolyte includes 35 mol % to 65 mol % of lithium (Li) oxide, 5 mol % to 25 mol % of silicon (Si) oxide, and 30 mol % to 50 mol % of boron (B) oxide, based on the total amount of the lithium borosilicate-based electrolyte.

8. The all-solid-state battery according to claim 6, wherein: The lithium borosilicate-based electrolyte further includes an additional oxide, comprising Na (sodium), Mg (magnesium), Al (aluminum), P (phosphorus), K (potassium), Ca (calcium), Ti (titanium), V (vanadium), Cr (chromium), Mn (manganese), Fe (iron), Co (cobalt), Ni (nickel), Cu (copper), Zn (zinc), Ga (gallium), Ge (germanium), Se (selenium), Rb (rubidium), S (sulfur), Y (yttrium), Zr (zirconium), Nb (niobium), Mo (molybdenum), Ag (silver), In (indium), Sn (tin), Sb (antimony), Cs (cesium), Ba (vanadium), Hf (hafnium), Ta (tantalum), W (tungsten), Pb (lead), Bi (bismuth), Au (gold), La (lanthanum), Nd (neodymium), Eu (europium), or a combination thereof.

9. The all-solid-state battery according to claim 6, wherein: The lithium borosilicate-based electrolyte also includes additives, which include LiF, LiCl, LiBr, LiI, Li3N, LiPON, Li2C2O4, Li2CO3, LiAlCl4, Li2O, Li2S, LiSO4, Li2SO4, Li3PO4, Li3VO4, Li4GeO4, Li2Si2O5, Li2SiO3, Li4SiO4, Li4ZrO4, LiMoO4, LiAlF4, Li3Ni2, LiBF4, LiCF3SO3 or combinations thereof.

10. The all-solid-state battery according to claim 1, wherein: A ratio of an average thickness of the first electrolyte layer to an average thickness of the second electrolyte layer is 1:1 to 15:

1.

11. The all-solid-state battery according to claim 1, further comprising: An edge layer is provided on the solid electrolyte layer and is laterally adjacent to an edge of the positive electrode layer or an edge of the negative electrode layer.

12. An all-solid-state battery, comprising: a positive electrode layer, a negative electrode layer, and a solid electrolyte layer interposed between the positive electrode layer and the negative electrode layer, The solid electrolyte layer includes a first electrolyte layer and a second electrolyte layer, the first electrolyte layer includes a glass ceramic electrolyte including lithium chloride (LiCl), and the second electrolyte layer is provided on one surface of the first electrolyte layer and includes a lithium borosilicate-based electrolyte. The first electrolyte layer is provided between the negative electrode layer and the second electrolyte layer, and the second electrolyte layer is provided between the positive electrode layer and the first electrolyte layer.

13. The all-solid-state battery according to claim 12, wherein: The glass-ceramic electrolyte further includes lithium chloroborate crystals.

14. The all-solid-state battery according to claim 12, wherein: The glass-ceramic electrolyte further includes lithium (Li) oxide, boron (B) oxide, silicon (Si) oxide, phosphorus (P) oxide, and germanium (Ge) oxide.

15. The all-solid-state battery according to claim 14, wherein: The glass ceramic electrolyte includes 35 mol % to 55 mol % of lithium (Li) oxide, 30 mol % to 50 mol % of boron (B) oxide, 5 mol % to 15 mol % of silicon (Si) oxide, 0.1 mol % to 5 mol % of phosphorus (P) oxide, 0.1 mol % to 5 mol % of germanium (Ge) oxide, and 0.5 mol % to 10 mol % of lithium chloride, based on the total amount of the glass ceramic electrolyte.

16. The all-solid-state battery according to claim 12, wherein: The lithium borosilicate-based electrolyte includes lithium (Li) oxide, silicon (Si) oxide, and boron (B) oxide.

17. The all-solid-state battery according to claim 16, wherein: The lithium borosilicate-based electrolyte includes 35 mol % to 65 mol % of lithium (Li) oxide, 5 mol % to 25 mol % of silicon (Si) oxide, and 30 mol % to 50 mol % of boron (B) oxide, based on the total amount of the lithium borosilicate-based electrolyte.

18. The all-solid-state battery according to claim 16, wherein: The lithium borosilicate-based electrolyte further includes an additional oxide, comprising Na (sodium), Mg (magnesium), Al (aluminum), P (phosphorus), K (potassium), Ca (calcium), Ti (titanium), V (vanadium), Cr (chromium), Mn (manganese), Fe (iron), Co (cobalt), Ni (nickel), Cu (copper), Zn (zinc), Ga (gallium), Ge (germanium), Se (selenium), Rb (rubidium), S (sulfur), Y (yttrium), Zr (zirconium), Nb (niobium), Mo (molybdenum), Ag (silver), In (indium), Sn (tin), Sb (antimony), Cs (cesium), Ba (vanadium), Hf (hafnium), Ta (tantalum), W (tungsten), Pb (lead), Bi (bismuth), Au (gold), La (lanthanum), Nd (neodymium), Eu (europium), or a combination thereof.

19. The all-solid-state battery according to claim 16, wherein: The lithium borosilicate-based electrolyte also includes additives, which include LiF, LiCl, LiBr, LiI, Li3N, LiPON, Li2C2O4, Li2CO3, LiAlCl4, Li2O, Li2S, LiSO4, Li2SO4, Li3PO4, Li3VO4, Li4GeO4, Li2Si2O5, Li2SiO3, Li4SiO4, Li4ZrO4, LiMoO4, LiAlF4, Li3Ni2, LiBF4, LiCF3SO3 or combinations thereof.

20. The all-solid-state battery according to claim 12, wherein: A ratio of an average thickness of the first electrolyte layer to an average thickness of the second electrolyte layer is 1:1 to 15:

1.

21. The all-solid-state battery according to claim 12, further comprising: An edge layer is provided on the solid electrolyte layer and is laterally adjacent to an edge of the positive electrode layer or an edge of the negative electrode layer.

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