Positive electrode for all-solid-state battery, all-solid-state battery including same, and method of manufacturing same

Abstract

A positive electrode layer, an all-solid-state battery including the positive electrode layer, and a method of manufacturing the positive electrode layer are disclosed. The positive electrode layer comprises a positive electrode current collector and a positive electrode active material layer, and the positive electrode active material layer comprises a first active material layer, a second active material layer and a middle layer. The first active material layer includes a first positive electrode active material, a first solid electrolyte, a first binder, and a first conductive material. The second active material layer includes a second positive electrode active material, a second solid electrolyte, a second binder, and a second conductive material. The intermediate layer includes a third solid electrolyte, a third binder, and a third conductive material. A total amount of the third solid electrolyte, the third binder, and the third conductive material is about 50 wt% or more relative to a total weight of the intermediate layer.

Description

[0001] This application claims priority to Korean Patent Application No. 10-2024-0109648, filed on August 16, 2024, with the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference. Technical Field

[0002] This disclosure relates to a positive electrode for an all-solid-state battery, an all-solid-state battery including the positive electrode, and a method for manufacturing the positive electrode, and more specifically, to a multilayer film for transferring an all-solid-state battery cell. Background Technology

[0003] The development of high-energy-density and safe batteries is driven by industrial demand. For example, lithium-ion batteries are being commercialized not only in information-related and communication devices, but also in industries such as the automotive industry. In the automotive industry, safety is emphasized because it is directly related to protecting human life.

[0004] All-solid-state batteries use a solid electrolyte instead of a liquid electrolyte. Because all-solid-state batteries typically do not use flammable organic dispersion media, the likelihood of fire or explosion is significantly reduced, even in the event of a short circuit. Summary of the Invention

[0005] Some example embodiments of this disclosure include all-solid-state batteries with improved stability and desired or improved electrochemical properties.

[0006] According to some example embodiments of this disclosure, the positive electrode layer for an all-solid-state battery may include a positive electrode current collector and a positive electrode active material layer on the positive electrode current collector. The positive electrode active material layer may include a first active material layer on the positive electrode current collector, a second active material layer on the first active material layer, and an intermediate layer between the first and second active material layers. The first active material layer may include a first positive electrode active material, a first solid electrolyte, a first binder, and a first conductive material. The second active material layer may include a second positive electrode active material, a second solid electrolyte, a second binder, and a second conductive material. The intermediate layer may include a third solid electrolyte, a third binder, and a third conductive material. The total amount of the third solid electrolyte, third binder, and third conductive material in the intermediate layer may be equal to or greater than about 50 wt% relative to the total weight of the intermediate layer.

[0007] According to some example embodiments of this disclosure, an all-solid-state battery may include a positive electrode layer, a negative electrode layer, and a solid electrolyte layer between the positive electrode layer and the negative electrode layer. The positive electrode layer may include a positive electrode current collector and a positive electrode active material layer on the positive electrode current collector. The positive electrode active material layer may include a positive electrode active material, a solid electrolyte, a binder, and a conductive material. The positive electrode active material layer may include a first portion adjacent to the positive electrode current collector, a second portion at the center of the positive electrode active material layer, and a third portion adjacent to the solid electrolyte layer. The second portion may be located between the first and third portions. The amount of positive electrode active material in the second portion may be less than the amount of positive electrode active material in the first portion. The amount of positive electrode active material in the second portion may be less than the amount of positive electrode active material in the third portion.

[0008] According to some example embodiments of this disclosure, a method for manufacturing a positive electrode layer for an all-solid-state battery may include the following steps: coating a first positive electrode slurry onto a positive electrode current collector to form a first active material layer; forming an intermediate layer on the first active material layer; and disposing a first self-standing film on the intermediate layer to form a second active material layer. The first active material layer may include a first positive electrode active material, a first solid electrolyte, a first binder, and a first conductive material. The second active material layer may include a second positive electrode active material, a second solid electrolyte, a second binder, and a second conductive material. The intermediate layer may include a third solid electrolyte, a third binder, and a third conductive material. The total amount of the third solid electrolyte, the third binder, and the third conductive material in the intermediate layer may be equal to or greater than about 50 wt% relative to the total weight of the intermediate layer. Attached Figure Description

[0009] Figure 1 The illustration shows a cross-sectional view of an all-solid-state battery according to some embodiments of the present disclosure.

[0010] Figure 2 The illustration shows Figure 1 A magnified view of part M.

[0011] Figures 3 to 6 The illustration shows a cross-sectional view illustrating a method for manufacturing a positive electrode layer for an all-solid-state battery according to some embodiments of the present disclosure.

[0012] Figure 7 The illustration shows Figure 1 A magnified view of part M.

[0013] Figure 8 and Figure 9 The illustration shows a cross-sectional view illustrating a method for forming a first composite layer according to some embodiments of the present disclosure.

[0014] Figure 10 and Figure 11The illustration shows a cross-sectional view illustrating a method for forming a second composite layer according to some embodiments of the present disclosure.

[0015] Figure 12 and Figure 13 The illustration shows a cross-sectional view illustrating a method for manufacturing a positive electrode layer for an all-solid-state battery according to some embodiments of the present disclosure.

[0016] Figure 14 This is a flowchart illustrating a method for manufacturing a positive electrode layer for an all-solid-state battery according to various example embodiments. Detailed Implementation

[0017] To fully understand the structure and effects of this disclosure, some exemplary embodiments of the disclosure have been described with reference to the accompanying drawings. However, it should be noted that this disclosure is not limited to the following exemplary embodiments and can be implemented in various forms. Rather, the exemplary embodiments are provided merely to disclose the disclosure and to enable those skilled in the art to fully understand its scope.

[0018] In this disclosure, it is understood that when an element is referred to as being "on" another element, the element may be "directly on" the other element, or an intervening element may be present therein. In the accompanying drawings, the thickness of some components is exaggerated for the purpose of effectively explaining the technical content. Throughout the specification, the same reference numerals denote the same elements.

[0019] Unless otherwise specifically stated in this specification, singular expressions may include plural expressions. Furthermore, unless otherwise specifically stated, the phrase "A or B" may mean "A but not B," "B but not A," and "A and B." The term "including / comprises" and / or variations thereof as used in this disclosure do not exclude the presence or addition of one or more other components.

[0020] In this disclosure, the term "combination thereof" may refer to mixtures, stacks, complexes, copolymers, alloys, blends, or reaction products.

[0021] In this disclosure, the term "metal" can include metals or metalloids (such as silicon and germanium) that are in an elemental or ionic state.

[0022] In this disclosure, the term "alloy" may refer to a mixture of two or more metals.

[0023] In this disclosure, the term "positive electrode active material" may refer to a positive electrode material capable of lithiation and delithiation.

[0024] In this disclosure, the term "negative electrode active material" may refer to a negative electrode material capable of lithiation and delithiation.

[0025] In this disclosure, the term "lithiation" and its variations may refer to the process of adding lithium to a positive electrode active material or a negative electrode active material.

[0026] In this disclosure, the term "delithiation" and its variations may refer to the process of removing lithium from positive electrode active material or negative electrode active material.

[0027] In this disclosure, the term "charging" and its variations can refer to the process by which a battery provides electrochemical energy.

[0028] In this disclosure, the term "discharge" and its variations may refer to the process of removing electrochemical energy from a battery.

[0029] In this disclosure, the term "positive electrode" may refer to an electrode that undergoes electrochemical reduction and lithiation during the discharge process.

[0030] In this disclosure, the term "negative electrode" may refer to an electrode that undergoes electrochemical oxidation and delithiation during the discharge process.

[0031] When the terms “about” or “basic” are used in conjunction with numerical values ​​in this specification, the relevant numerical values ​​are intended to include a tolerance of ±10% around the stated value. When a range is specified, the range includes all values ​​in increments such as 0.1%.

[0032] Figure 1 The illustration shows a cross-sectional view of an all-solid-state battery according to some exemplary embodiments of the present disclosure. (Refer to...) Figure 1 This illustration shows a single cell 10 of an all-solid-state battery according to an exemplary embodiment of the present disclosure. The single cell 10 may include a positive electrode layer 100, a negative electrode layer 200 opposite to the positive electrode layer 100, and a solid electrolyte layer 300 between the positive electrode layer 100 and the negative electrode layer 200. However, the present disclosure is not limited thereto, and the single cell 10 may also include additional functional layers, such as an adhesive reinforcement layer, between the positive electrode layer 100 and the solid electrolyte layer 300 or between the negative electrode layer 200 and the solid electrolyte layer 300. The single cell 10 may be a battery stack.

[0033] The positive electrode layer 100 may include a positive electrode current collector 110 and a positive electrode active material layer 120 on the positive electrode current collector 110. The positive electrode active material layer 120 may include at least one of a positive electrode active material, a solid electrolyte, a conductive material, and a binder.

[0034] The positive electrode current collector 110 can provide a reference surface, on which the positive electrode active material layer 120 is disposed. The positive electrode current collector 110 can have a plate or foil shape. For example, the positive electrode current collector 110 may include at least one of indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li), and alloys thereof.

[0035] In another embodiment of this disclosure, the positive electrode current collector 110 may be omitted. Although not shown, in order to increase the adhesion between the positive electrode current collector 110 and the positive electrode active material layer 120, a carbon layer with a thickness in the range of about 0.1 μm to about 4 μm may be further provided between the positive electrode current collector 110 and the positive electrode active material layer 120.

[0036] The positive electrode active material may include materials capable of reversibly absorbing and desorbing lithium ions. For example, the positive electrode active material may include at least one of lithium transition metal oxides (e.g., lithium cobalt oxide (LCO), lithium nickel oxide, lithium nickel cobalt oxide, lithium nickel cobalt aluminum oxide (NCA), lithium nickel cobalt manganese oxide (NCM), lithium manganese oxide, or lithium iron phosphate), nickel sulfide, copper sulfide, lithium sulfide, iron oxide, and vanadium oxide, but this disclosure is not limited thereto. The positive electrode active material may be included alone or as a mixture of two or more substances.

[0037] Lithium transition metal oxides may be or include, for example, those made of Li a A 1-b B b D2 (where 0.90≤a≤1 and 0≤b≤0.5), Li a E 1-b B b O 2-c D c (Where, 0.90≤a≤1, 0≤b≤0.5 and 0≤c≤0.05), LiE 2-b B b O 4-c D c (where 0 ≤ b ≤ 0.5 and 0 ≤ c ≤ 0.05), Li a Ni 1-b-c Co b B c D α (Where, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05 and 0<α<2), Li a Ni 1-b-c Co b B c O 2-α F α(Where, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05 and 0<α<2), Li a Ni 1-b- c Mn b B c D α (Where, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05 and 0<α≤2), Li a Ni 1-b-c Mn b B c O 2-α F α (Where, 0.90≤a≤1, 0≤b≤0.5, 0≤c≤0.05 and 0<α<2), Li a Ni b E c G d O2 (where 0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5 and 0.001≤d≤0.1), Li a Ni b Co c Mn d G e O2 (where 0.90≤a≤1, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5 and 0.001≤e≤0.1), Li a NiG b O2 (where 0.9≤a≤1 and 0.001≤b≤0.1), Li a CoG b O2 (where 0.90≤a≤1 and 0.001≤b≤0.1), Li a MnG b O2 (where 0.90≤a≤1 and 0.001≤b≤0.1), Li a Mn2G b O4 (where 0.90≤a≤1 and 0.001≤b≤0.1), QO2, QS2, LiQS2, V2O5, LiV2O5, LiIO2, LiNiVO4, Li 3-f J2(PO4)3 (where 0≤f≤2), Li 3-fA compound represented by one of Fe2(PO4)3 (where 0 ≤ f ≤ 2) and LiFePO4. In the above compound, "A" can be or include at least one of Ni, Co, Mn, and combinations thereof; "B" can be or include at least one of Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements, and combinations thereof; "D" can be or include at least one of O, F, S, P, and combinations thereof; "E" can be or include at least one of Co, Mn, and combinations thereof; "F" can be or include at least one of F, S, P, and combinations thereof; "G" can be or include at least one of Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, and combinations thereof; "Q" can be or include at least one of Ti, Mo, Mn, and combinations thereof; "I" can be or include at least one of Cr, V, Fe, Sc, Y, and combinations thereof; "J" can be or include at least one of V, Cr, Mn, Co, Ni, Cu, and combinations thereof.

[0038] The positive electrode active material can include, for example, a lithium salt of a transition metal oxide having a layered rock salt-type structure among the lithium transition metal oxides discussed above. The term "layered rock salt-type structure" can refer to a structure in which oxygen atom layers and metal atom layers are alternately and regularly arranged in the <111> direction of the cubic rock salt-type structure, where each atom layer forms a two-dimensional plane. The term "cubic rock salt-type structure" can refer to the sodium chloride (NaCl)-type structure as a type of crystal structure, and for example, has a structure in which face-centered cubic (FCC) lattices formed by cations and anions respectively are offset by 1 / 2 of the ridge of the unit lattice from each other. The lithium transition metal oxide having a layered rock salt-type structure can be or include a ternary lithium transition metal oxide, such as LiNi x Co y Al z O2 (NCA) or LiNi x Co y Mn z O2 (NCM) (where 0 < x < 1, 0 < y < 1, 0 < z < 1, and x + y + z = 1). When the positive electrode active material includes a ternary lithium transition metal oxide having a layered rock salt-type structure, the single cell 10 can have an increased energy density and improved thermal stability.

[0039] The compound included in the positive electrode active material may be coated (not shown). The positive electrode active material may be included in a mixture of the compound and the compound to which the coating is added. The coating added to the surface of the positive electrode active material may include at least one of the oxides, hydroxides, hydroxyoxides, oxycarbonates, and bicarbonates of the coating element, as discussed below. The compound forming the coating may be amorphous or crystalline. The coating element included in the coating may include at least one of Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, and mixtures thereof. The coating may include, for example, Li₂O-ZrO₂ (LZO). The method for forming the coating may be any method that does not negatively affect the physical properties of the positive electrode active material. The method for forming the coating may include, for example, spraying or dipping.

[0040] When the positive electrode active material is a ternary lithium transition metal oxide (such as NCA or NCM) including nickel (Ni), the capacity density of the single cell 10 can be increased to reduce metal leaching from the positive electrode active material under charging conditions. Therefore, the single cell 10 can improve its cycle characteristics under charging conditions. The term "cycle characteristics" can refer to a property indicating the degree of degradation of the single cell 10 due to charging and discharging. For example, a single cell 10 with high cycle characteristics may degrade less due to charging and discharging, while a single cell 10 with low cycle characteristics may degrade more due to charging and discharging.

[0041] The positive electrode active material can have a particle shape, for example, approximately spherical or approximately elliptical. There are no restrictions on the particle size and amount of the positive electrode active material.

[0042] Solid electrolytes can include sulfide-based solid electrolytes with desired or improved lithium-ion conductivity. Sulfide-based solid electrolytes can include, for example, Li₂S-P₂S₅, Li₂S-P₂S₅-LiX (where X is or includes a halogen element), Li₂S-P₂S₅-Li₂O, Li₂S-P₂S₅-Li₂O-LiI, Li₂S-SiS₂, Li₂S-SiS₂-LiI, Li₂S-SiS₂-LiBr, Li₂S-SiS₂-LiCl, Li₂S-SiS₂-B₂S₃-LiI, Li₂S-SiS₂-P₂S₅-LiI, Li₂S-B₂S₃, and Li₂S-P₂S₅-Z. m S n (Where m and n are each positive integers, and "Z" is or includes one of Ge, Zn, and Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q(Where p and q are each positive integers, and "M" is or includes one of P, Si, Ge, B, Al, Ga, and In), Li 7-x PS 6-x Cl x (where 0≤x≤2), Li 7-x PS 6-x Br x (where 0 ≤ x ≤ 2) and Li 7-x PS 6-x I x At least one of the following (where 0 ≤ x ≤ 2).

[0043] Sulfide solid electrolytes may be or include argentite-germanium sulfide compounds, such as Li 7-x PS 6-x Cl x (where 0≤x≤2), Li 7-x PS 6-x Br x (where 0 ≤ x ≤ 2) and Li 7-x PS 6-x I x (where 0 ≤ x ≤ 2). For example, sulfide solid electrolytes may be or include sulfide-germanium ore-type compounds containing at least one of Li6PS5Cl, Li6PS5Br and Li6PS5I.

[0044] For example, sulfide solid electrolytes may be or include those containing Li 7-a M a PS 6-c X c A sulfide-germanium ore type compound (where 0 ≤ a ≤ 2 and 0 ≤ c ≤ 2). In the above chemical formula, X can be or include at least one of F, Br, Cl and combinations thereof. Additionally, M may be or include at least one of scandium (Sc), yttrium (Y), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), arsenic (As), antimony (Sb), bismuth (Bi), and combinations thereof.

[0045] The sulfide-germanium ore type solid electrolyte can have a density in the range of about 1.5 g / cc to about 2.0 g / cc. Because the sulfide-germanium ore type solid electrolyte has a density equal to or greater than about 1.5 g / cc, the internal resistance of the all-solid-state battery can be reduced, and short circuits in the solid electrolyte layer and penetration caused by lithium dendrite formation can be hindered or prevented. The solid electrolyte can have an elastic modulus, for example, in the range of about 15 GPa to about 35 GPa.

[0046] The medium average particle size (D) of the solid electrolyte included in the positive electrode active material layer 120 50 The particle size can be smaller than the average particle size of the solid electrolyte included in the solid electrolyte layer 300. For example, the average particle size (D) of the solid electrolyte in the positive electrode active material layer 120 is smaller than that of the solid electrolyte in the solid electrolyte layer 300. 50 ) can be the medium-sized average particle size (D) of the solid electrolyte included in the solid electrolyte layer 300. 50 The percentages of the medium-sized average particle size (D) are equal to or less than about 90%, equal to or less than about 80%, equal to or less than about 70%, equal to or less than about 60%, equal to or less than about 50%, equal to or less than about 40%, equal to or less than about 30%, or equal to or less than about 20%. 50 The median diameter can be measured using a laser particle size distribution analyzer.

[0047] The positive electrode active material layer 120 may include a conductive material. The conductive material can exhibit conductivity without causing chemical changes in the single cell 10, and can increase the conductivity of both the positive electrode active material and the solid electrolyte. The conductive material may include carbon-based materials. The conductive material may include one or more of, for example, graphite, carbon black, acetylene black, carbon nanofibers, and carbon nanotubes.

[0048] The positive electrode active material layer 120 may further include an adhesive. The adhesive may include a material that causes the positive electrode active material, solid electrolyte, and conductive material included in the positive electrode active material layer 120 to adhere to each other and improves the adhesion between the positive electrode active material layer 120 and the positive electrode current collector 110. The adhesive may include at least one of, for example, polyvinylidene fluoride, styrene-butadiene rubber (SBR), polytetrafluoroethylene, polyethylene, polyvinyl alcohol, polyvinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, and polymethyl methacrylate.

[0049] In the positive electrode active material layer 120, the positive electrode active material may be included in an amount ranging from about 85 parts by weight to about 92 parts by weight, relative to the total of 100 parts by weight of the positive electrode active material, solid electrolyte, conductive material and binder.

[0050] In the positive electrode active material layer 120, the conductive material may be present in an amount ranging from about 1 part by weight to about 50 parts by weight relative to 100 parts by weight of the solid electrolyte. When the conductive material is present in an amount less than about 1 part by weight relative to 100 parts by weight of the solid electrolyte, the conductivity of the positive electrode active material layer 120 may decrease. When the conductive material is present in an amount greater than about 50 parts by weight relative to 100 parts by weight of the solid electrolyte, the proportion of the conductive material may increase significantly, resulting in the coating covering the surface of the solid electrolyte not being fully formed.

[0051] According to some example embodiments, in addition to the positive electrode active material, solid electrolyte, conductive material and binder, the positive electrode active material layer 120 may also include at least one additive, such as or including at least one of filler, coating agent, dispersant and ionic conductive agent.

[0052] A solid electrolyte layer 300 may be disposed between the positive electrode layer 100 and the negative electrode layer 200, and may include a sulfide-based solid electrolyte with desired or improved lithium-ion conductivity. The solid electrolyte included in the solid electrolyte layer 300 may include the same or different materials as those included in the solid electrolyte included in the positive electrode active material layer 120.

[0053] In an example embodiment, the solid electrolyte layer 300 may include a sulfide-based solid electrolyte. The sulfide-based solid electrolyte can be prepared, for example, by melting and quenching or mechanically grinding a starting material such as Li₂S or P₂S₅. Additionally, the resulting solid electrolyte product may be heat-treated after the above treatment. The solid electrolyte may be in an amorphous state, a crystalline state, or a mixture of amorphous and crystalline states. The solid electrolyte may include at least one of the component elements included in the above-described sulfide-based solid electrolyte: sulfur (S), phosphorus (P), and lithium (Li). For example, the solid electrolyte may be or include materials comprising Li₂S-P₂S₅. When materials comprising Li₂S-P₂S₅ are included as the sulfide-based solid electrolyte material of the solid electrolyte, the molar ratio of Li₂S and P₂S₅ may be in the range of about 50:50 to about 90:10 (or Li₂S:P₂S₅ = 50:50-90:10).

[0054] Sulfide solid electrolytes may be or include argentite-germanium sulfide compounds, such as Li 7-x PS 6-x Cl x (where 0≤x≤2), Li 7-x PS 6-x Br x (where 0 ≤ x ≤ 2) and Li 7-x PS 6-xI x (where 0 ≤ x ≤ 2). For example, sulfide solid electrolytes may be or include sulfide-germanium ore-type compounds containing at least one of Li6PS5Cl, Li6PS5Br and Li6PS5I.

[0055] For example, sulfide solid electrolytes may be or include those containing Li 7-a M a PS 6-c X c A sulfide-germanium ore type compound (where 0 ≤ a ≤ 2 and 0 ≤ c ≤ 2). In the above chemical formula, X can be or include at least one of F, Br, Cl and combinations thereof. Additionally, M may be or include at least one of scandium (Sc), yttrium (Y), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), arsenic (As), antimony (Sb), bismuth (Bi), and combinations thereof.

[0056] The sulfide-germanium ore type solid electrolyte can have a density in the range of about 1.5 g / cc to about 2.0 g / cc. Since the sulfide-germanium ore type solid electrolyte has a density equal to or greater than about 1.5 g / cc, the internal resistance of the all-solid-state battery can be reduced, and short circuits in the solid electrolyte membrane and penetration caused by lithium dendrite formation can be hindered or prevented. The solid electrolyte can have an elastic modulus, for example, in the range of about 15 GPa to about 35 GPa.

[0057] The solid electrolyte layer 300 may also include a binder. The binder included in the solid electrolyte layer 300 may include, for example, at least one of styrene-butadiene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, and polyethylene, but this disclosure is not limited thereto. The binder of the solid electrolyte layer 300 may be the same as or similar to the binder of the positive electrode active material layer 120 or the binder of the negative electrode coating 220 discussed below.

[0058] The negative electrode layer 200 may include a negative electrode current collector 210 and a negative electrode coating 220 on the negative electrode current collector 210. The negative electrode current collector 210 may provide a reference surface on which the negative electrode coating 220 is disposed. The negative electrode current collector 210 may include a material that does not react with lithium or substantially does not react with lithium, such as a material that does not form alloys or compounds with lithium. For example, the negative electrode current collector 210 may include a metal such as or containing at least one of copper (Cu), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), and nickel (Ni). The thickness of the negative electrode current collector 210 may range from about 1 μm to about 20 μm, for example, from about 5 μm to about 15 μm or from about 7 μm to about 10 μm.

[0059] The negative electrode current collector 210 may be formed of one of the aforementioned metals, an alloy of two or more of the aforementioned metals, or a coating material, or may include one of the aforementioned metals, an alloy of two or more of the aforementioned metals, or a coating material. The negative electrode current collector 210 may have, for example, a plate shape or a foil shape. In the example embodiment, the negative electrode current collector 210 may be omitted.

[0060] When the single cell 10 is charged, the negative electrode coating 220 can induce the growth of lithium metal between the negative electrode coating 220 and the negative electrode current collector 210. The negative electrode coating 220 can be configured as a protective layer for lithium metal and can simultaneously or concurrently hinder or suppress the precipitation and growth of lithium dendrites.

[0061] The negative electrode coating 220 may include metals and carbon. For example, the negative electrode coating 220 may include a metal such as or comprising at least one of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn). The negative electrode coating 220 may include at least one carbon, such as or comprising at least one of carbon black, acetylene black, furnace black, Ketjen black, and graphene. In an example embodiment, the negative electrode coating 220 may include a mixture of carbon black and silver (Ag).

[0062] In addition to metals and carbon, the negative electrode coating 220 may also include additives. The negative electrode coating 220 may include at least one additive, such as or including at least one of binders, fillers, coating agents, dispersants, and ionic conductive agents.

[0063] The thickness of the negative electrode coating 220 can be less than the thickness of the positive electrode active material layer 120. For example, the thickness of the negative electrode coating 220 can be equal to or less than about 50%, equal to or less than about 40%, equal to or less than about 30%, equal to or less than about 20%, equal to or less than about 10%, or equal to or less than about 5% of the thickness of the positive electrode active material layer 120. The negative electrode coating 220 can have a thickness in the range of, for example, about 1 μm to about 20 μm, about 2 μm to about 10 μm, or about 3 μm to about 7 μm. When the negative electrode coating 220 has a relatively small thickness, lithium dendrites formed between the negative electrode coating 220 and the negative electrode current collector 210 may cause the negative electrode coating 220 to collapse, thereby reducing the cycle characteristics of the single cell 10. When the negative electrode coating 220 has a relatively large thickness, the single cell 10 may have a reduced energy density and increased internal resistance caused by the negative electrode coating 220, thereby reducing the cycle characteristics of the single cell 10.

[0064] Although not shown, a carbon layer may be further included to increase the adhesion between the negative electrode coating 220 and the solid electrolyte layer 300.

[0065] According to some exemplary embodiments of this disclosure, the width of the positive electrode layer 100 may be smaller than the width of the negative electrode layer 200. For example, the positive electrode layer 100 may have a first width W1 in the first direction D1, and the negative electrode layer 200 may have a second width W2 in the first direction D1. The first width W1 may be smaller than the second width W2. Since the first width W1 is smaller than the second width W2, a gasket may also be provided on the outer periphery of the positive electrode layer 100 to compensate for the width difference.

[0066] Reference Figure 1 According to some exemplary embodiments of this disclosure, the solid electrolyte layer 300 may include a positive electrode solid electrolyte layer 300a and a negative electrode solid electrolyte layer 300b. The positive electrode solid electrolyte layer 300a and the negative electrode solid electrolyte layer 300b may be stacked to form the solid electrolyte layer 300. The positive electrode solid electrolyte layer 300a may be in contact with the positive electrode active material layer 120, and the negative electrode solid electrolyte layer 300b may be in contact with the negative electrode coating 220.

[0067] For example, the positive electrode solid electrolyte layer 300a and the negative electrode solid electrolyte layer 300b may include solid electrolytes having the same composition. Alternatively, the positive electrode solid electrolyte layer 300a and the negative electrode solid electrolyte layer 300b may include solid electrolytes with different compositions.

[0068] The positive electrode solid electrolyte layer 300a may have a first width W1, and the negative electrode solid electrolyte layer 300b may have a second width W2. For example, the width of the positive electrode solid electrolyte layer 300a may be smaller than the width of the negative electrode solid electrolyte layer 300b. The first width W1 of the positive electrode solid electrolyte layer 300a may be smaller than the second width W2 of the negative electrode solid electrolyte layer 300b. Since the first width W1 of the positive electrode solid electrolyte layer 300a is smaller than the second width W2 of the negative electrode solid electrolyte layer 300b, a gasket may also be provided on the outer periphery of the positive electrode solid electrolyte layer 300a to compensate for the width difference.

[0069] Figure 2 The illustration shows Figure 1 A magnified view of part M. For the sake of brevity, details have been omitted to avoid elaboration on the above references. Figure 1 The discussion of the positive electrode layer is redundant.

[0070] Reference Figure 2 The positive electrode active material layer 120 can be disposed on the positive electrode current collector 110. The positive electrode active material layer 120 may include a first active material layer AL1 on the positive electrode current collector 110, a second active material layer AL2 on the first active material layer AL1, and an intermediate layer ALM disposed between the first active material layer AL1 and the second active material layer AL2.

[0071] The first active material layer AL1 may include at least one of a first positive electrode active material, a first solid electrolyte, a first binder, and a first conductive material. In the first active material layer AL1, the first positive electrode active material may be present in an amount ranging from about 85 wt% to about 92 wt% relative to the total weight of the first active material layer AL1, and the first binder may be present in an amount equal to or less than about 5 wt% relative to the total weight of the first active material layer AL1.

[0072] The intermediate layer ALM may include at least one of a third solid electrolyte, a third binder, and a third conductive material. In the intermediate layer ALM, the total amount of the third solid electrolyte, the third binder, and the third conductive material relative to the total weight of the intermediate layer ALM may be equal to or greater than about 50 wt%. For example, the amount of the third binder relative to the total weight of the intermediate layer ALM may be equal to or greater than about 10 wt%. The ionic conductivity of the intermediate layer ALM at a temperature in the range of about 25°C to about 35°C may be in the range of about 0.83 mS / cm to about 0.98 mS / cm.

[0073] The intermediate ALM layer may include a third positive electrode active material. The amount of the third positive electrode active material in the intermediate ALM layer may be less than the amount of the first positive electrode active material in the first active material layer AL1, and less than the amount of the second positive electrode active material in the second active material layer AL2, discussed below. The amount of the third positive electrode active material in the intermediate ALM layer may be equal to or less than about 50 wt% relative to the total weight of the intermediate ALM layer. In some exemplary embodiments of this disclosure, the intermediate ALM layer may not include a third positive electrode active material.

[0074] The second active material layer AL2 may include a second positive electrode active material, a second solid electrolyte, a second binder, and a second conductive material. In the second active material layer AL2, the second positive electrode active material may be present in an amount ranging from about 85 wt% to about 92 wt% relative to the total weight of the second active material layer AL2, and the second binder may be present in an amount equal to or less than about 5 wt% relative to the total weight of the second active material layer AL2.

[0075] The second active material layer AL2 may further include a porous membrane PW impregnated therein. The porous membrane PW may include multiple pores. For example, the porous membrane PW may have a porosity in the range of about 50% to about 99%, about 60% to about 95%, or about 70% to about 90%. The pores of the porous membrane PW may each have a size in the range of about 50 nm to about 500 nm or about 100 nm to about 300 nm. When the porosity and pore size of the porous membrane PW fall within the above-mentioned ranges, the positive electrode active material can easily permeate into the porous membrane PW. The porous membrane PW may contain an amount of active material sufficient to constitute a self-standing positive electrode membrane.

[0076] Porous membrane PWs can have small thicknesses. The thickness of porous membrane PWs can range from about 5 μm to about 20 μm, from about 5 μm to about 15 μm, or from about 8 μm to about 10 μm. When the thickness of the porous membrane PW falls within the above range, the loading level of the positive electrode can be improved without significantly interrupting the movement of lithium ions in the positive electrode.

[0077] Porous membranes (PW) can have a density of approximately 2 g / m³. 2 Approximately 4g / m 2 The weight range is [not specified]. For example, the weight of a porous membrane (PW) can be approximately 2.5 g / m³. 2 Approximately 3.5 g / m 2 Within the range.

[0078] Porous membranes (PW) can have tensile strength in the range of about 0.1 N / mm to about 0.2 N / mm. For example, the tensile strength of porous membranes (PW) can be in the range of about 0.1 N / mm to about 0.13 N / mm.

[0079] The permeability per unit thickness of a porous membrane (PW) can range from about 0.1 s / 100 mL to about 1 s / 100 mL. For example, the permeability per unit thickness of a porous membrane (PW) can range from about 0.1 s / 100 mL to about 0.5 s / 100 mL.

[0080] Porous membranes (PW) may include at least one of polyester, polyolefin, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyethersulfone, polyphenylene ether, polyphenylene sulfide, and crystalline carbon. For example, polyester may include at least one of polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate.

[0081] According to some exemplary embodiments of this disclosure, the porous membrane PW may comprise crystalline carbon, such as porous carbonaceous sheets. The porous membrane PW may comprise one or more of single-walled carbon nanotubes and multi-walled carbon nanotubes. Because the porous membrane PW comprises porous carbonaceous sheets, it can provide desired or improved mechanical strength and stability. According to some exemplary embodiments of this disclosure, the porous membrane PW may be or comprise a porous nonwoven fabric.

[0082] According to some exemplary embodiments of this disclosure, the positive electrode layer 100 for an all-solid-state battery may include a porous membrane PW disposed in a positive electrode active material layer 120, and the positive electrode active material layer 120 may include multiple positive electrode active material layers AL1, ALM, AL2 on the upper and lower sides of the porous membrane PW, thereby achieving a high loading level. In this disclosure, the term "loading level" may refer to the amount of active material per unit area of ​​electrode and may be a factor designed taking into account the diffusion coefficient of lithium ions, interparticle conduction, and the path to the current collector.

[0083] In the positive electrode of an all-solid-state battery according to an example embodiment, the positive electrode active material layer 120 located on one side of the positive electrode current collector 110 may have a concentration equal to or greater than about 35 mg / cm³. 2 For example, equal to or greater than approximately 40 mg / cm³ 2 or equal to or greater than approximately 45 mg / cm³ 2 The load level.

[0084] According to some exemplary embodiments, when the positive electrode active material layer 120 is coated on opposite sides of the positive electrode current collector 110, the total loading of the positive electrode active material layer 120 can be equal to or greater than about 70 mg / cm³. 2 For example, equal to or greater than approximately 80 mg / cm³ 2 Or equal to or greater than approximately 90 mg / cm³ 2 .

[0085] According to some exemplary embodiments of this disclosure, the positive electrode layer 100 for an all-solid-state battery may include an intermediate layer ALM disposed between a first active material layer AL1 and a second active material layer AL2. The total amount of solid electrolyte, binder, and conductive material in the intermediate layer ALM may be equal to or greater than about 50 wt% relative to the total weight of the intermediate layer ALM. The large amount of binder in the intermediate layer ALM can improve the adhesion between the first active material layer AL1 and the intermediate layer ALM, and between the second active material layer AL2 and the intermediate layer ALM. Therefore, the positive electrode layer 100 for an all-solid-state battery can improve stability.

[0086] The abundant binder in the intermediate ALM layer allows each of the first active material layer AL1 and the second active material layer AL2 to have a binder content equal to or less than about 5 wt%. Therefore, each of the first active material layer AL1 and the second active material layer AL2 can possess a large amount of positive electrode active material and increased capacity. Furthermore, the abundant solid electrolyte in the intermediate ALM layer can improve the ionic conductivity of the all-solid-state battery.

[0087] For example, the second active material layer AL2 can be manufactured in the form of a self-standing membrane as discussed below. The second active material layer AL2 can be manufactured in the form of a self-standing membrane and disposed on the first active material layer AL1, thereby providing an all-solid-state battery including a thick film with a high loading capacity.

[0088] The first positive electrode active material to the third positive electrode active material, the first solid electrolyte to the third solid electrolyte, the first binder to the third binder, and the first conductive material to the third conductive material can be respectively compared with reference to... Figure 1 The positive electrode active material, solid electrolyte, binder, and conductive material discussed are basically the same.

[0089] According to some exemplary embodiments of this disclosure, the first active material layer AL1, the intermediate layer ALM, and the second active material layer AL2 may have a blurred interface between them and may integrally constitute a positive electrode active material layer 120.

[0090] In this case, the positive electrode active material layer 120 may include: a first portion AR1 on the positive electrode current collector 110; a third portion AR3 adjacent to the solid electrolyte layer 300; and a second portion AR2 at the center of the positive electrode active material layer 120 and between the first portion AR1 and the third portion AR3.

[0091] In the example, the first part AR1 can correspond to the first active material layer AL1. The second part AR2 can correspond to the intermediate layer ALM, and the third part AR3 can correspond to the second active material layer AL2.

[0092] For example, the second portion AR2 can be defined by the concentration distribution of the solid electrolyte, binder, and conductive material. For instance, the total amount of the solid electrolyte, binder, and conductive material can increase sharply in the second portion AR2, and the amount of the positive electrode active material can decrease sharply in the second portion AR2. The second portion AR2 can be defined as referring to a given portion where the total amount of the solid electrolyte, binder, and conductive material suddenly increases and then decreases sharply, and / or the amount of the positive electrode active material suddenly decreases and then increases sharply. Furthermore, the upper side of a given portion (or the second portion AR2) can be defined as the third portion AR3, and the lower side of a given portion (or the second portion AR2) can be defined as the first portion AR1.

[0093] The concentration distribution of solid electrolytes, binders, and conductive materials can be measured by optical methods, electron microscopy analysis, or X-ray diffraction analysis, but this disclosure is not limited thereto.

[0094] Figures 3 to 6 The figure illustrates a cross-sectional view of a method for manufacturing a positive electrode layer for an all-solid-state battery according to some exemplary embodiments of the present disclosure. For the sake of brevity, omissions have been made to avoid further elaboration on the above references. Figure 1 The discussion of the positive electrode layer is redundant.

[0095] Reference Figure 3 The wound positive electrode current collector 110 can be unwound and fed into the coating process. The traveling positive electrode current collector 110 can be transported and coated on the support roller SRL in the first direction D1. On the support roller SRL, the positive electrode current collector 110 can undergo the coating process.

[0096] The coating die CTD can be disposed adjacent to the support roller SRL. The coating die CTD can include two holes for slurry injection. The two slurry injection holes can be respectively provided with a first positive electrode slurry ASL1 and a third positive electrode slurry ASL3. The coating die CTD can be configured such that the first positive electrode slurry ASL1 and the third positive electrode slurry ASL3 are coated (e.g., sequentially coated) on the positive electrode current collector 110.

[0097] The first positive electrode paste ASL1 may include a first positive electrode active material, a first solid electrolyte, a first binder, and a first conductive material. The third positive electrode paste ASL3 may include a third positive electrode active material, a third solid electrolyte, a third binder, and a third conductive material. The amount of the third positive electrode active material in the third positive electrode paste ASL3 may be equal to or less than about 50 wt%. The total amount of the third solid electrolyte, the third binder, and the third conductive material in the third positive electrode paste ASL3 may be equal to or greater than about 50 wt%, and the amount of the third binder in the third positive electrode paste ASL3 may be equal to or greater than about 10 wt%. According to some exemplary embodiments of this disclosure, the third positive electrode paste ASL3 may not include the third positive electrode active material.

[0098] The solvent in each of the first positive electrode paste ASL1 and the third positive electrode paste ASL3 can be any suitable solvent commonly used in the art, for example, it can include at least one of dimethyl sulfoxide (DMSO), isopropanol, N-methylpyrrolidone (NMP), acetone, water, and combinations thereof.

[0099] The first positive electrode paste ASL1 and the third positive electrode paste ASL3 coated on the positive electrode current collector 110 can be dried to form a first preliminary positive electrode active material layer PAL1 and a preliminary intermediate layer PAM. For example, the first preliminary positive electrode active material layer PAL1 can correspond to Figure 2 The first active material layer AL1, and the preliminary intermediate layer PAM can correspond to Figure 2 The intermediate layer ALM.

[0100] Reference Figure 4 A release membrane RF can be placed on a plane defined by a first direction D1 and a second direction D2. The second direction D2 may intersect with the first direction D1. A preliminary porous membrane PWA can be formed on the release membrane RF. The preliminary porous membrane PWA can be stacked on the release membrane RF along a third direction D3. The third direction D3 may intersect with each of the first direction D1 and the second direction D2. As described above, the preliminary porous membrane PWA may include a plurality of pores. The pores of the preliminary porous membrane PWA may each have a size in the range of about 50 nanometers to about 500 nanometers. The preliminary porous membrane PWA may have a small thickness. The preliminary porous membrane PWA may have a thickness in the range of about 5 μm to about 20 μm. For example, the thickness of the preliminary porous membrane PWA may be in the range of about 5 μm to about 15 μm or in the range of about 8 μm to about 12 μm. In an example embodiment, the preliminary porous membrane PWA may be or include a porous nonwoven fabric.

[0101] An adhesive BD can be laminated onto a preliminary porous membrane (PWA). The preliminary porous membrane (PWA) may include a first region A1 on which the adhesive BD is laminated and a second region A2 not laminated with the adhesive BD, and the first region A1 may be located on opposite sides or at both ends of the preliminary porous membrane (PWA). The second region A2 may be a region other than the first region A1.

[0102] The binder BD can be formed by coating and then curing it onto the first region A1 of the preliminary porous membrane PWA. The binder BD may include at least one of a thermosetting resin and a UV-curable resin.

[0103] After the binder BD is formed, a second positive electrode slurry ASL2 can be provided on the preliminary porous membrane PWA. The second positive electrode slurry ASL2 can be provided on the second region A2 of the preliminary porous membrane PWA.

[0104] The second positive electrode paste ASL2 may include a second positive electrode active material, a second solid electrolyte, a second conductive material, and a second binder. The descriptions of the second positive electrode active material, the second solid electrolyte, the second conductive material, and the second binder included in the second positive electrode paste ASL2 are consistent with the above references. Figure 1 and Figure 2 The descriptions in the discussion are the same. In the example embodiment, the second positive electrode slurry ASL2 may include at least one of styrene-butadiene rubber, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polyvinyl alcohol, polyvinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, and polymethyl methacrylate as a binder.

[0105] After coating the preliminary porous membrane PWA with the second positive electrode paste ASL2, the second positive electrode paste ASL2 can be cured. The second positive electrode paste ASL2 provided on the second region A2 of the preliminary porous membrane PWA can permeate into the preliminary porous membrane PWA. For example, when the second positive electrode paste ASL2 is provided on the second region A2, the second positive electrode paste ASL2 can permeate into the pores of the preliminary porous membrane PWA. The second positive electrode paste ASL2 can permeate into the pores of the preliminary porous membrane PWA to form a porous membrane PW whose pores are filled with the second positive electrode paste ASL2.

[0106] Reference Figure 5After the second positive electrode paste ASL2 is coated and penetrates into the preliminary porous membrane PWA, at least a portion of the second region A2 of the porous membrane PW can be spaced apart from the release membrane RF. A portion of the second positive electrode paste ASL2 can move through the pores of the porous membrane PW, such that a second preliminary active material layer PA2 can be formed between the porous membrane PW and the release membrane RF. A portion of the second positive electrode paste ASL2 can not penetrate the porous membrane PW, and a third preliminary active material layer PA3 can be formed on the porous membrane PW.

[0107] The thickness of the second preliminary active material layer PA2, which moves through the pores of the porous membrane PW, can be less than the thickness of the third preliminary active material layer PA3, which does not penetrate the porous membrane PW. In an example embodiment, the thickness ratio of the third preliminary active material layer PA3 to the second preliminary active material layer PA2 can be in the range of about 2 to about 10, about 3 to about 10, or about 4 to about 7.

[0108] Although not shown in detail, the second positive electrode paste ASL2, included in each of the second preliminary active material layer PA2 and the third preliminary active material layer PA3, can have a single integral shape with the active material impregnated in the porous membrane PW. After coating and curing the second positive electrode paste ASL2, a composite layer CMM can be formed, comprising the second preliminary active material layer PA2, the third preliminary active material layer PA3, and the porous membrane PW disposed between the second preliminary active material layer PA2 and the third preliminary active material layer PA3.

[0109] The release film RF can then be peeled off. For example, the release film RF can be separated from the composite layer CMM. Therefore, the release film RF can include materials that can be separated from the composite layer CMM. For example, the release film RF can include at least one of polyethylene terephthalate, polypropylene, polymethylpentene, and any copolymers thereof.

[0110] The porous membrane PW included in the composite layer CMM can have a self-supporting membrane shape. A self-supporting membrane can refer to a thin layer or membrane that maintains a given shape independently without being supported by another substrate. In an example embodiment, the composite layer CMM can have a shape composed of… Figure 5 The shape depicted is formed by the components from which the release membrane RF, adhesive BD, and preliminary porous membrane PWA corresponding to the first region A1 have been removed.

[0111] Reference Figure 6 You can refer to the above. Figure 3 A second preliminary positive electrode active material layer PAL2 is disposed on the first preliminary positive electrode active material layer PAL1 and the preliminary intermediate layer PAM. The second preliminary positive electrode active material layer PAL2 may be or include the above-mentioned references. Figure 4 and Figure 5The composite layer CMM is discussed, and it can be constructed to face the initial intermediate layer PAM.

[0112] After the second preliminary positive electrode active material layer PAL2 is formed, the stacked (e.g., sequentially stacked) positive electrode current collector 110, first preliminary positive electrode active material layer PAL1, preliminary intermediate layer PAM, and second preliminary positive electrode active material layer PAL2 can be pressed together as a whole by a pressing unit PRU. The pressing unit PRU can press the stacked (e.g., sequentially stacked) positive electrode current collector 110, first preliminary positive electrode active material layer PAL1, preliminary intermediate layer PAM, and second preliminary positive electrode active material layer PAL2. The pressing unit PRU may include a pressing roller.

[0113] Return to reference Figure 2 The positive electrode active material layer 120 can be formed by a pressing process using a pressing unit (PRU). For example, in the pressing process, the first preliminary positive electrode active material layer PAL1 can be formed as the first active material layer AL1, the preliminary intermediate layer PAM can be formed as the intermediate layer ALM, and the second preliminary positive electrode active material layer PAL2 can be formed as the second active material layer AL2.

[0114] Figure 7 The illustration shows Figure 1 A magnified view of part of the "M". For the sake of brevity, omissions have been made to avoid further elaboration on the above references. Figure 1 The discussion of the positive electrode layer is redundant.

[0115] The positive electrode active material layer 120 can be disposed on the positive electrode current collector 110. The positive electrode active material layer 120 may include a first active material layer AL1 on the positive electrode current collector 110, a second active material layer AL2 on the first active material layer AL1, and an intermediate layer ALM disposed between the first active material layer AL1 and the second active material layer AL2.

[0116] The first active material layer AL1 may include a first positive electrode active material, a first solid electrolyte, a first binder, and a first conductive material. For example, in the first active material layer AL1, the first positive electrode active material may be present in an amount ranging from about 85 wt% to about 92 wt% relative to the total weight of the first active material layer AL1, and the first binder may be present in an amount equal to or less than about 5 wt% relative to the total weight of the first active material layer AL1.

[0117] The intermediate ALM layer may include a third solid electrolyte, a third binder, and a third conductive material. In the intermediate ALM layer, the total amount of the third solid electrolyte, the third binder, and the third conductive material relative to the total weight of the intermediate ALM layer may, for example, be equal to or greater than about 50 wt%. The amount of the third binder relative to the total weight of the intermediate ALM layer may, for example, be equal to or greater than about 10 wt%. The ionic conductivity of the intermediate ALM layer at a temperature in the range of about 25°C to about 35°C may be in the range of about 0.83 mS / cm to about 0.98 mS / cm.

[0118] The intermediate ALM layer may include a third positive electrode active material. The amount of the third positive electrode active material in the intermediate ALM layer may be less than the amount of the first positive electrode active material in the first active material layer AL1, and less than the amount of the second positive electrode active material in the second active material layer AL2, discussed below. The amount of the third positive electrode active material in the intermediate ALM layer may be equal to or less than about 50 wt% relative to the total weight of the intermediate ALM layer. In some exemplary embodiments of this disclosure, the intermediate ALM layer may not include a third positive electrode active material. The intermediate ALM layer may include a first porous membrane PW1 impregnated therein.

[0119] The first porous membrane PW1 may include a plurality of pores. For example, the permeability of the first porous membrane PW1 may be in the range of about 50% to about 99%, about 60% to about 95%, or about 70% to about 90%. The pores of the first porous membrane PW1 may each have a size in the range of about 50 nm to about 500 nm or about 100 nm to about 300 nm. When the porosity and pore size of the first porous membrane PW1 fall within the above ranges, the positive electrode active material can easily permeate into the first porous membrane PW1, and the first porous membrane PW1 can contain a sufficient amount of active material to act as a self-standing membrane for the positive electrode.

[0120] The first porous membrane PW1 can have a small thickness. The thickness of the first porous membrane PW1 can be in the range of about 5 μm to about 20 μm, about 5 μm to about 15 μm, or about 8 μm to about 10 μm. When the thickness of the first porous membrane PW1 falls within the above range, the loading level of the positive electrode can be significantly improved without substantially interrupting the movement of lithium ions in the positive electrode.

[0121] The first porous membrane PW1 can have a density of approximately 2 g / m³. 2 Approximately 4g / m 2 The weight range. For example, the weight of the first porous membrane PW1 can be approximately 2.5 g / m³. 2 Approximately 3.5 g / m 2 Within the range.

[0122] The first porous membrane PW1 can have a tensile strength in the range of about 0.1 N / mm to about 0.2 N / mm. For example, the tensile strength of the first porous membrane PW1 can be in the range of about 0.1 N / mm to about 0.13 N / mm.

[0123] The permeability per unit thickness of the first porous membrane PW1 can be in the range of about 0.1 seconds / 100 mL to about 1 second / 100 mL. For example, the permeability per unit thickness of the first porous membrane PW1 can be in the range of about 0.1 seconds / 100 mL to about 0.5 seconds / 100 mL.

[0124] The first porous membrane PW1 may include at least one of polyester, polyolefin, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyethersulfone, polyphenylene ether, polyphenylene sulfide, and crystalline carbon. For example, polyester may include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc.

[0125] According to some exemplary embodiments of this disclosure, the first porous membrane PW1 may comprise crystalline carbon, such as a porous carbon sheet. In this case, the first porous membrane PW1 may comprise one or more of single-walled carbon nanotubes and multi-walled carbon nanotubes. Because the first porous membrane PW1 comprises a porous carbon sheet, it can provide desired or improved mechanical strength and stability. According to some exemplary embodiments of this disclosure, the first porous membrane PW1 may be or comprise a porous nonwoven fabric.

[0126] The second active material layer AL2 may include a second positive electrode active material, a second solid electrolyte, a second binder, and a second conductive material. For example, in the second active material layer AL2, the second positive electrode active material may be present in an amount ranging from about 85 wt% to about 92 wt% relative to the total weight of the second active material layer AL2, and the second binder may be present in an amount equal to or less than about 5 wt% relative to the total weight of the second active material layer AL2. The second active material layer AL2 may include a second porous membrane PW2 impregnated therein. The description of the second porous membrane PW2 may be substantially the same as the description of the first porous membrane PW1.

[0127] According to some exemplary embodiments of this disclosure, the positive electrode layer 100 for an all-solid-state battery may include a first porous film PW1 and a second porous film PW2 disposed in a positive electrode active material layer 120, and the positive electrode active material layer 120 may include a plurality of positive electrode active material layers AL1, AL2 disposed on the upper and lower sides of each of the first porous film PW1 and the second porous film PW2, thereby achieving a high loading level. In this disclosure, the term "loading level" may refer to the amount of active material per unit area of ​​electrode and may be a factor designed taking into account the diffusion coefficient of lithium ions, conduction between particles, and the path to the current collector.

[0128] In the positive electrode of an all-solid-state battery according to an example embodiment, the positive electrode active material layer 120 located on one side of the positive electrode current collector 110 may have a concentration equal to or greater than about 35 mg / cm³. 2 The load level, for example, equal to or greater than about 40 mg / cm³ 2 Or equal to or greater than approximately 45 mg / cm³ 2 The load level.

[0129] According to some exemplary embodiments, when the positive electrode active material layer 120 is coated on opposite sides of the positive electrode current collector 110, the total loading of the positive electrode active material layer 120 can be equal to or greater than about 70 mg / cm³. 2 For example, equal to or greater than approximately 80 mg / cm³ 2 Or equal to or greater than approximately 90 mg / cm³ 2 .

[0130] Furthermore, the positive electrode layer 100 for an all-solid-state battery according to some example embodiments of this disclosure may include an intermediate layer ALM disposed between a first active material layer AL1 and a second active material layer AL2. The total amount of solid electrolyte, binder, and conductive material in the intermediate layer ALM may be equal to or greater than about 50 wt% relative to the total weight of the intermediate layer ALM. The large amount of binder in the intermediate layer ALM can improve the adhesion between the first active material layer AL1 and the intermediate layer ALM, and between the second active material layer AL2 and the intermediate layer ALM. Therefore, the positive electrode layer 100 for an all-solid-state battery can improve stability.

[0131] The abundant binder in the intermediate ALM layer allows each of the first active material layer AL1 and the second active material layer AL2 to have a binder content equal to or less than about 5 wt%. Therefore, each of the first active material layer AL1 and the second active material layer AL2 can possess a large amount of positive electrode active material and increased capacity. Furthermore, the abundant solid electrolyte in the intermediate ALM layer can improve the ionic conductivity of the all-solid-state battery.

[0132] Furthermore, the second active material layer AL2 can be manufactured in the form of a self-standing membrane as described below. The second active material layer AL2 can be manufactured in the form of a self-standing membrane and disposed on the first active material layer AL1, thereby providing an all-solid-state battery including a thick film with a high loading capacity.

[0133] The first positive electrode active material to the third positive electrode active material, the first solid electrolyte to the third solid electrolyte, the first binder to the third binder, and the first conductive material to the third conductive material can be respectively compared with reference to... Figure 1 The positive electrode active material, solid electrolyte, binder, and conductive material discussed are basically the same.

[0134] According to some exemplary embodiments of this disclosure, the first active material layer AL1, the intermediate layer ALM, and the second active material layer AL2 may have a blurred interface between them and may integrally form a positive electrode layer 100.

[0135] In this case, the positive electrode active material layer 120 may include a first part AR1 on the positive electrode current collector 110, a third part AR3 adjacent to the solid electrolyte layer 300, and a second part AR2 located between the first part AR1 and the third part AR3.

[0136] The first part AR1 can correspond to the first active material layer AL1. The second part AR2 can correspond to the intermediate layer ALM, and the third part AR3 can correspond to the second active material layer AL2.

[0137] For example, the second portion AR2 can be defined by the concentration distribution of solid electrolyte, binder, and conductive material. For instance, relative to the first portion AR1, the total amount of solid electrolyte, binder, and conductive material can increase sharply in the second portion AR2, and relative to the first portion AR1, the amount of positive electrode active material can decrease sharply in the second portion AR2. The second portion AR2 can be defined as a given portion in which the total amount of solid electrolyte, binder, and conductive material suddenly increases and then decreases sharply, and / or the amount of positive electrode active material suddenly decreases and then increases sharply. Furthermore, the upper side of a given portion (or the second portion AR2) can be defined as the third portion AR3, and the lower side of a given portion (or the second portion AR2) can be defined as the first portion AR1.

[0138] The concentration distribution of solid electrolytes, binders, and conductive materials can be measured by optical methods, electron microscopy analysis, or X-ray diffraction analysis, but this disclosure is not limited thereto.

[0139] Figures 8 to 13This is a cross-sectional view illustrating a method for manufacturing a positive electrode layer for an all-solid-state battery according to some exemplary embodiments of the present disclosure. For the sake of brevity, omissions have been made to avoid further elaboration on the above references. Figure 1 The discussion of the positive electrode layer is redundant.

[0140] Figure 8 and Figure 9 This is a cross-sectional view illustrating a method for forming a first composite layer according to some example embodiments of the present disclosure.

[0141] A first release membrane RF1 can be placed on a plane defined by a first direction D1 and a second direction D2. The second direction D2 may intersect with the first direction D1. A first preliminary porous membrane PWA1 can be disposed on the first release membrane RF1. The first preliminary porous membrane PWA1 can be stacked on the first release membrane RF1 along a third direction D3. The third direction D3 may intersect with each of the first direction D1 and the second direction D2.

[0142] The first preliminary porous membrane PWA1 may include a plurality of pores. The pores of the first preliminary porous membrane PWA1 may all have a size in the range of about 50 nanometers to about 500 nanometers. The first preliminary porous membrane PWA1 may have a small thickness. The first preliminary porous membrane PWA1 may have a thickness in the range of about 5 μm to about 20 μm. For example, the thickness of the first preliminary porous membrane PWA1 may be in the range of about 5 μm to about 15 μm or about 8 μm to about 12 μm. In some exemplary embodiments of this disclosure, the first preliminary porous membrane PWA1 may be or include a porous carbon sheet.

[0143] A first adhesive BD1 can be laminated on a first preliminary porous membrane PWA1. The first preliminary porous membrane PWA1 may include a first region A1 on which the first adhesive BD1 is laminated and a second region A2 not laminated with the first adhesive BD1, and the first region A1 may be located on opposite sides or at both ends of the first preliminary porous membrane PWA1. The second region A2 may be a region other than the first region A1.

[0144] The first adhesive BD1 can be formed by coating and then curing it onto the first region A1 of the first preliminary porous membrane PWA1. The first adhesive BD1 may include at least one of thermosetting resin and ultraviolet-curable resin.

[0145] After the first binder BD1 is formed, a third positive electrode paste ASL3 can be provided or deposited on the first preliminary porous membrane PWA1. The third positive electrode paste ASL3 can be provided on the second region A2 of the first preliminary porous membrane PWA1.

[0146] The third positive electrode paste ASL3 may include a third positive electrode active material, a third solid electrolyte, a third conductive material, and a third binder. The descriptions of the third positive electrode active material, the third solid electrolyte, the third conductive material, and the third binder included in the third positive electrode paste ASL3 are consistent with the above references. Figure 1 and Figure 7 The descriptions discussed are the same. According to some example embodiments of this disclosure, the third positive electrode slurry ASL3 may not include a third positive electrode active material.

[0147] For example, the third positive electrode paste ASL3 may include at least one of styrene-butadiene rubber, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polyvinyl alcohol, polyvinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile and polymethyl methacrylate as a third binder.

[0148] After the third positive electrode paste ASL3 is coated onto the first preliminary porous membrane PWA1, the third positive electrode paste ASL3 can be cured. The third positive electrode paste ASL3 provided on the second region A2 of the first preliminary porous membrane PWA1 can permeate into the first preliminary porous membrane PWA1. For example, when the third positive electrode paste ASL3 is provided on the second region A2, the third positive electrode paste ASL3 can permeate into the pores of the first preliminary porous membrane PWA1. The third positive electrode paste ASL3 can permeate into the pores of the first preliminary porous membrane PWA1 to form a first porous membrane PW1 whose pores are filled with the third positive electrode paste ASL3.

[0149] Reference Figure 9 After the third positive electrode paste ASL3 is coated and penetrates into the first preliminary porous membrane PWA1, at least a portion of the second region A2 of the first porous membrane PW1 can be spaced apart from the first release membrane RF1. A portion of the third positive electrode paste ASL3 can move through the pores of the first porous membrane PW1, such that a second preliminary active material layer PA2 can be formed between the first porous membrane PW1 and the first release membrane RF1. A portion of the third positive electrode paste ASL3 can not penetrate the first porous membrane PW1 to form a third preliminary active material layer PA3 on the first porous membrane PW1.

[0150] The thickness of the second preliminary active material layer PA2, which moves through the pores of the first porous membrane PW1, can be less than the thickness of the third preliminary active material layer PA3, which does not penetrate the first porous membrane PW1. In an example embodiment, the thickness ratio of the third preliminary active material layer PA3 to the second preliminary active material layer PA2 can be in the range of about 2 to about 10, about 3 to about 10, or about 4 to about 7.

[0151] Although not shown in detail, the third positive electrode paste ASL3 included in each of the second preliminary active material layer PA2 and the third preliminary active material layer PA3 can have a single integral shape with the active material impregnated in the first porous membrane PW1. After coating and curing the third positive electrode paste ASL3, a first composite layer CMM1 can be formed, which includes the second preliminary active material layer PA2, the third preliminary active material layer PA3, and the first porous membrane PW1 disposed between the second preliminary active material layer PA2 and the third preliminary active material layer PA3.

[0152] The first release film RF1 can then be peeled off. For example, the first release film RF1 can be separated from the first composite layer CMM1. Therefore, the first release film RF1 may include a material that can be separated from the first composite layer CMM1. For example, the first release film RF1 may include at least one of polyethylene terephthalate, polypropylene, polymethylpentene, and any copolymer thereof.

[0153] The first porous membrane PW1 included in the first composite layer CMM1 may have a self-standing membrane shape. A self-standing membrane can refer to a thin layer or membrane that maintains a given shape without being supported by another substrate. In an example embodiment, the first composite layer CMM1 may have a shape composed of... Figure 9 The shape depicted is formed by the components from which the first release membrane RF1, the first adhesive BD1, and the first preliminary porous membrane PWA1 corresponding to the first region A1 have been removed.

[0154] Figure 10 and Figure 11 This is a cross-sectional view illustrating a method for forming a second composite layer according to some example embodiments of the present disclosure.

[0155] Reference Figure 10 and Figure 11 The second positive electrode paste ASL2 can be provided or deposited on the second preliminary porous membrane PWA2 disposed on the second release membrane RF2. The second positive electrode paste ASL2 can be provided on the second region A2 of the second preliminary porous membrane PWA2. The arrangement of the second release membrane RF2, the second preliminary porous membrane PWA2 and the second binder BD2 can be substantially the same as the arrangement of the first release membrane RF1, the first preliminary porous membrane PWA1 and the first binder BD1.

[0156] The second positive electrode paste ASL2 may include a second positive electrode active material, a second solid electrolyte, a second conductive material, and a second binder. The descriptions of the second positive electrode active material, the second solid electrolyte, the second conductive material, and the second binder included in the second positive electrode paste ASL2 are consistent with the above references. Figure 1 and Figure 7 The descriptions in the discussion are the same.

[0157] Reference Figure 11 After the second positive electrode paste ASL2 is coated and penetrates into the second preliminary porous membrane PWA2, at least a portion of the second region A2 of the second porous membrane PW2 can be spaced apart from the second release membrane RF2. A portion of the second positive electrode paste ASL2 can move through the pores of the second porous membrane PW2, such that a fourth preliminary active material layer PA4 can be formed between the second porous membrane PW2 and the second release membrane RF2. A portion of the second positive electrode paste ASL2 can not penetrate the second porous membrane PW2 to form a fifth preliminary active material layer PA5 on the second porous membrane PW2.

[0158] Although not shown in detail, the second positive electrode paste ASL2 included in each of the fourth and fifth preliminary active material layers PA4 and PA5 can have a single integral shape with the active material impregnated in the second porous membrane PW2. After coating and curing the second positive electrode paste ASL2, a second composite layer CMM2 can be formed, comprising the fourth preliminary active material layer PA4, the fifth preliminary active material layer PA5, and the second porous membrane PW2 disposed between the fourth and fifth preliminary active material layers PA4 and PA5.

[0159] The second release film RF2 can then be peeled off. For example, the second release film RF2 can be separated from the second composite layer CMM2.

[0160] The second porous membrane PW2, included in the second composite layer CMM2, can have a self-standing membrane shape. Apart from the differences discussed above, the method for forming the second composite layer CMM2 can be the same as described above. Figure 8 and Figure 9 The methods for forming the first composite layer CMM1 discussed are basically the same.

[0161] Figure 12 and Figure 13 This is a cross-sectional view illustrating a method for manufacturing a positive electrode layer according to some example embodiments of the present disclosure.

[0162] Reference Figure 12 A first preliminary positive electrode active material layer PAL1 can be formed on the positive electrode current collector 110. The first preliminary positive electrode active material layer PAL1 can, for example, be formed only on one side of the positive electrode current collector 110. A positive electrode slurry can be coated and dried on one side of the positive electrode current collector 110 to form the first preliminary positive electrode active material layer PAL1. The first positive electrode slurry may include a first positive electrode active material, a first solid electrolyte, a first binder, and a first conductive material. The descriptions of the first positive electrode active material, the first solid electrolyte, the first binder, and the first conductive material can be found in reference [reference needed]. Figure 1 and Figure 7 The descriptions of the first positive electrode active material, the first solid electrolyte, the first binder, and the first conductive material are the same.

[0163] A preliminary intermediate layer PAM and a second preliminary positive electrode active layer PAL2 can be stacked (e.g., sequentially stacked) on a first preliminary positive electrode active material layer PAL1 formed on the positive electrode current collector 110. The preliminary intermediate layer PAM can correspond to the above-mentioned reference. Figure 8 and Figure 9 The first composite layer CMM1 is discussed, and can be configured to allow the second preliminary active material layer PA2 to face the first preliminary positive electrode active material layer PAL1. The second preliminary positive electrode active material layer PAL2 can correspond to the above reference. Figure 10 and Figure 11 The second composite layer CMM2 is discussed, and can be configured to allow the fourth preliminary active material layer PA4 to face the third preliminary active material layer PA3 of the first composite layer CMM1.

[0164] Reference Figure 13 The pressing unit (PRU) can press together the stacked (e.g., sequentially stacked) positive electrode current collector 110, first preliminary positive electrode active material layer PAL1, preliminary intermediate layer PAM, and second preliminary positive electrode active material layer PAL2. The pressing unit (PRU) can also include a pressing roller.

[0165] Return to reference Figure 7 The positive electrode active material layer 120 can be formed by a pressing process using a pressing unit (PRU). For example, in the pressing process, the first preliminary positive electrode active material layer PAL1 can be formed as the first active material layer AL1, the preliminary intermediate layer PAM can be formed as the intermediate layer ALM, and the second preliminary positive electrode active material layer PAL2 can be formed as the second active material layer AL2.

[0166] Figure 14 This is a flowchart illustrating a method for manufacturing a positive electrode layer for an all-solid-state battery according to various example embodiments. In the example, method 1400 includes operations 1410, 1420, and 1430. Operation 1410 includes coating a first positive electrode slurry onto a positive electrode current collector to form a first active material layer. For example, the first active material layer includes a first positive electrode active material, a first solid electrolyte, a first binder, and a first conductive material. In another example, the amount of the first binder in the first active material layer is equal to or less than about 5 wt% relative to the total weight of the first active material layer.

[0167] Operation 1420 includes forming an intermediate layer on a first active material layer. For example, the intermediate layer includes a third solid electrolyte, a third binder, and a third conductive material. In one example, the total amount of the third solid electrolyte, the third binder, and the third conductive material in the intermediate layer is equal to or greater than about 50 wt% relative to the total weight of the intermediate layer. In another example, forming the intermediate layer includes coating a second positive electrode slurry onto a release film. In yet another example, forming the intermediate layer includes disposing a second self-standing membrane on a release film.

[0168] Operation 1430 includes disposing of a first self-standing membrane on an intermediate layer to form a second active material layer. For example, the second active material layer includes a second positive electrode active material, a second solid electrolyte, a second binder, and a second conductive material.

[0169] This disclosure is described in detail herein with reference to some exemplary embodiments.

[0170] Example 1 Prepare LiNi0.8Co0. 15 Mn0. 05 O2 (NCM) powder was used as the first positive electrode active material. A crystalline silver-germanium sulfide type solid electrolyte (Li6PS5Cl) with an average particle size of 1.5 μm was prepared as the first solid electrolyte. Polyvinylidene fluoride (PVDF) was prepared as the first binder, and carbon nanofibers (CNF) were prepared as the first conductive material. The first positive electrode active material, the first solid electrolyte, the first conductive material, and the first binder were mixed in N-methylpyrrolidone solvent at a weight ratio of 85:13.5:0.5:1 to prepare a first positive electrode active material slurry. The first positive electrode active material slurry was coated onto an aluminum positive electrode current collector and dried, then pressed to manufacture the first positive electrode plate.

[0171] In addition, a slurry of the third positive electrode active material was prepared. LiNi0.8Co0 was prepared. 15 Mn0. 05 O2 (NCM) powder was used as the third positive electrode active material in the slurry. A crystalline silver sulfide germanite-type solid electrolyte (Li6PS5Cl) was prepared as the third solid electrolyte, polyvinylidene fluoride (PVDF) as the third binder, and carbon nanofibers (CNF) as the third conductive material. The third positive electrode active material, the third solid electrolyte, the third conductive material, and the third binder were mixed in N-methylpyrrolidone solvent at a weight ratio of 9:50.5:0.5:40 to prepare the third positive electrode active material slurry. The third positive electrode active material slurry was coated onto a porous nonwoven fabric with a thickness of 10 μm to prepare a first positive electrode active material composite layer in the form of a self-supporting membrane.

[0172] In addition, a slurry of the second positive electrode active material is prepared. LiNi0.8Co0 is prepared. 15 Mn0. 05 O2 (NCM) powder was used as the second positive electrode active material in the slurry. A crystalline silver sulfide germanite-type solid electrolyte (Li6PS5Cl) was prepared as the second solid electrolyte, polyvinylidene fluoride (PVDF) was prepared as the second binder, and carbon nanofibers (CNF) were prepared as the second conductive material. The second positive electrode active material, the second solid electrolyte, the second conductive material, and the second binder were mixed in an N-methylpyrrolidone solvent at a weight ratio of 85:13.5:0.5:1 to prepare the second positive electrode active material slurry.

[0173] The second positive electrode active material slurry was coated onto a porous nonwoven fabric with a thickness of 10 μm to prepare a second positive electrode active material composite layer in the form of a self-standing membrane.

[0174] A first positive electrode active material composite layer is stacked on a first positive electrode plate so that a porous nonwoven fabric is positioned close to the positive electrode current collector. Then, a second positive electrode active material composite layer is stacked on top of the first positive electrode active material composite layer so that the nonwoven fabric is positioned close to the positive electrode current collector. The resulting stack is pressed to manufacture the positive electrode.

[0175] A pressing process was performed using pressing rollers at 25°C, where the linear pressure of the pressing rollers was controlled at 2.3 tons, and the gap between the upper and lower rollers was adjusted to zero to press the positive electrode. This resulted in minimizing the thickness of the pressed positive electrode to achieve a high mixing density. The positive electrode was manufactured such that the active material on the current collector side had a concentration of 45 mg / cm³. 2 The load level.

[0176] Solid electrolyte layer: Li6PS5Cl, used as a sulforaphite-germanium ore type solid electrolyte, was added to an isobutyl isobutyrate binder solution containing acrylate polymers to prepare a solid electrolyte slurry (the solid electrolyte and binder were mixed at a weight ratio of 98.7:1.3). The prepared solid electrolyte slurry was coated onto a polytetrafluoroethylene release film and dried at 60°C for 2 hours to produce a solid electrolyte layer with a thickness of 100 μm.

[0177] Manufacturing of the negative electrode: A negative electrode coating slurry was prepared by mixing 90 wt% silver (Ag) nanoparticles (D50: 60 nm) and 10 wt% carbon black in an aqueous solvent. The carbon black was a mixture of individual particles with a particle size of 38 nm and secondary particles with a particle size of 275 nm, in which primary particles with a particle size of 76 nm were aggregated. The slurry was coated onto a stainless steel foil current collector and then dried to fabricate a negative electrode comprising a negative electrode coating with a thickness of 12 μm and a current collector with a thickness of 10 μm.

[0178] Subsequently, a positive electrode, a solid electrolyte layer, and a negative electrode were used to manufacture a full cell using conventional methods.

[0179] Comparative Example 1 The positive electrode is manufactured according to the same method as described in Example 1, except that when preparing the third positive electrode active material slurry, the third positive electrode active material, the third solid electrolyte, the third conductive material and the third binder are mixed in a weight ratio of 85:13.5:0.5:1.

[0180] Comparative Example 2 During the fabrication of the positive electrode, a first positive electrode active material composite layer was not formed. A first positive electrode active material slurry was coated and pressed onto an aluminum positive electrode current collector to fabricate a first positive electrode plate. A second positive electrode active material composite layer was then stacked on the first positive electrode plate with a porous nonwoven fabric positioned close to the positive electrode current collector. The resulting stack was then pressed to obtain the positive electrode. Except for the differences discussed above, the positive electrode was fabricated according to the same method described in Example 1.

[0181] Comparative Example 3 The first and second positive electrode active material composite layers, formed in the form of a self-standing film, are excluded from the manufacture of the positive electrode. A positive electrode active material slurry is coated onto an aluminum positive electrode current collector and dried, then pressed to manufacture a first positive electrode plate used as the positive electrode. The positive electrode is manufactured using the same method as described in Example 1. A full cell is manufactured using the manufactured positive electrode using the same method as described in Example 1.

[0182] Evaluation 1: Warping When the positive electrodes according to Example 1, Comparative Example 1 and Comparative Example 2 were left to stand in a drying chamber for 1 hour and placed on a flat floor, the maximum height of the positive electrode from the flat floor was measured.

[0183] Table 1:

[0184] Referring to Table 1, it can be observed that the warpage value of Example 1 is smaller than that of each of Comparative Examples 1 and 2. Therefore, it can be determined that the intermediate layer with a high binder dosage causes an increase in the stability of the positive electrode.

[0185] Evaluation 2: Cycle life characteristics of all-solid-state batteries Table 2 lists the evaluation results of the cycle life characteristics of the full cells manufactured according to Example 1 and Comparative Example 3.

[0186] Each charge (0.33C constant current / constant voltage charging to 4.25V, 0.05C cut-off) and discharge (0.33C constant current discharging to 3.0V, cut-off) in the all-solid-state batteries according to Example 1 and Comparative Example 3 is considered as the first cycle. Starting from the second cycle, the all-solid-state batteries are charged (1.0C constant current / constant voltage charging to 4.25V, 0.05C cut-off) and discharged (0.5C constant current discharging to 3.0V, cut-off) while monitoring the cycles until the capacity retention reaches 80%. The capacity retention for the nth cycle is calculated according to Mathematical Equation 1.

[0187] Mathematical Equation 1: Capacity retention (%) = [Discharge capacity in the nth cycle / Discharge capacity in the first cycle] × 100 Table 2:

[0188] Referring to Table 2, it can be determined that, compared with the all-solid-state battery according to Comparative Example 3, the all-solid-state battery according to Example 1 exhibits the desired or improved capacity retention.

[0189] According to some exemplary embodiments of this disclosure, the positive electrode layer may include a first active material layer, a second active material layer, and an intermediate layer disposed between the first and second active material layers. The total amount of solid electrolyte, binder, and conductive material in the intermediate layer may be equal to or greater than about 50 wt% relative to the total weight of the intermediate layer. A large amount of binder in the intermediate layer can improve the adhesion between the first active material layer and the intermediate layer, and between the second active material layer and the intermediate layer. Therefore, the all-solid-state battery can have increased stability and desired or improved electrochemical characteristics.

[0190] Furthermore, the large amount of solid electrolyte in the intermediate layer can provide an all-solid-state battery with improved ionic conductivity.

[0191] Although some exemplary embodiments of the present disclosure have been discussed with reference to the accompanying drawings, it is understood that various changes in form and detail may be made therein without departing from the spirit and scope of the present disclosure. It will be apparent to those skilled in the art that various substitutions, modifications, and alterations may be made therein without departing from the scope and spirit of the present disclosure.

Claims

1. A positive electrode layer for an all-solid-state battery, the positive electrode layer comprising: Positive electrode current collector; as well as The positive electrode active material layer is located on the positive electrode current collector. The positive electrode active material layer includes: A first active material layer is formed on the positive electrode current collector; A second active material layer is disposed on the first active material layer; and The intermediate layer, located between the first active material layer and the second active material layer, The first active material layer includes a first positive electrode active material, a first solid electrolyte, a first binder, and a first conductive material. The second active material layer includes a second positive electrode active material, a second solid electrolyte, a second binder, and a second conductive material. The intermediate layer comprises a third solid electrolyte, a third binder, and a third conductive material, and Wherein, relative to the total weight of the intermediate layer, the total amount of the third solid electrolyte, the third binder and the third conductive material in the intermediate layer is equal to or greater than 50 wt%.

2. The positive electrode layer as described in claim 1, wherein, The intermediate layer also includes a third positive electrode active material. The amount of the third positive electrode active material in the intermediate layer is equal to or less than 50 wt% relative to the total weight of the intermediate layer.

3. The positive electrode layer as described in claim 1, wherein, The intermediate layer also includes a first porous membrane impregnated in the intermediate layer. The first porous membrane comprises one or more of polyester, polyolefin, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyethersulfone, polyphenylene ether, polyphenylene sulfide, and crystalline carbon.

4. The positive electrode layer as described in claim 1, wherein, The second active material layer also includes a second porous membrane impregnated in the second active material layer. The second porous membrane comprises one or more of polyester, polyolefin, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyethersulfone, polyphenylene ether, polyphenylene sulfide, and crystalline carbon.

5. The positive electrode layer as described in claim 1, wherein, The amount of the third adhesive in the intermediate layer is equal to or greater than 10 wt% relative to the total weight of the intermediate layer.

6. The positive electrode layer as claimed in claim 1, wherein, The amount of the first binder in the first active material layer is equal to or less than 5 wt% relative to the total weight of the first active material layer.

7. The positive electrode layer as claimed in claim 1, wherein, Based on the positive electrode active material layer on the positive electrode current collector side, the loading level of the positive electrode layer is equal to or less than 35 mg / cm³. 2 .

8. The positive electrode layer as claimed in claim 1, wherein, At least one of the first adhesive, the second adhesive, and the third adhesive comprises at least one of styrene-butadiene rubber, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polyvinyl alcohol, polyvinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, and polymethyl methacrylate.

9. The positive electrode layer as described in claim 2, wherein, The amount of the first positive electrode active material in the first active material layer is greater than the amount of the third positive electrode active material in the intermediate layer.

10. The positive electrode layer as claimed in claim 1, wherein, The intermediate layer has an ionic conductivity in the range of 0.83 mS / cm to 0.98 mS / cm at temperatures ranging from 25°C to 35°C.

11. An all-solid-state battery, the all-solid-state battery comprising: Positive electrode layer; Negative electrode layer; as well as A solid electrolyte layer is located between the positive electrode layer and the negative electrode layer. The positive electrode layer includes a positive electrode current collector and a positive electrode active material layer on the positive electrode current collector. The positive electrode active material layer includes a positive electrode active material, a solid electrolyte, a binder, and a conductive material. The positive electrode active material layer has the following characteristics: The first part is adjacent to the positive electrode current collector; The second part is located at the center of the positive electrode active material layer; and The third part is adjacent to the solid electrolyte layer. The second part is located between the first part and the third part. Wherein, the amount of positive electrode active material in the second part is less than the amount of positive electrode active material in the first part, and The amount of positive electrode active material in the second part is less than the amount of positive electrode active material in the third part.

12. The all-solid-state battery as claimed in claim 11, wherein, The amount of positive electrode active material in the second part is equal to or less than 50 wt% relative to the total weight of the second part.

13. The all-solid-state battery as described in claim 11, wherein, The amount of adhesive in the second part is equal to or greater than 10 wt% relative to the total weight of the second part.

14. The all-solid-state battery as claimed in claim 11, wherein: The amount of adhesive in the first part is equal to or less than 5 wt% relative to the total weight of the first part, and The amount of adhesive in the third part is equal to or less than 5 wt% relative to the total weight of the third part.

15. The all-solid-state battery as claimed in claim 11, wherein, The positive electrode active material layer includes at least one porous membrane.

16. The all-solid-state battery of claim 15, wherein, The porous membrane comprises one or more of polyester, polyolefin, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyethersulfone, polyphenylene ether, polyphenylene sulfide, and crystalline carbon.

17. A method for manufacturing a positive electrode layer for an all-solid-state battery, the method comprising the steps of: A first positive electrode slurry is coated onto the positive electrode current collector to form a first active material layer; An intermediate layer is formed on the first active material layer; as well as A first self-standing membrane is disposed on the intermediate layer to form a second active material layer. The first active material layer includes a first positive electrode active material, a first solid electrolyte, a first binder, and a first conductive material. The second active material layer includes a second positive electrode active material, a second solid electrolyte, a second binder, and a second conductive material. The intermediate layer comprises a third solid electrolyte, a third binder, and a third conductive material, and Wherein, relative to the total weight of the intermediate layer, the total amount of the third solid electrolyte, the third binder and the third conductive material in the intermediate layer is equal to or greater than 50 wt%.

18. The method of claim 17, wherein, The step of forming the intermediate layer includes coating a second positive electrode paste onto the release film.

19. The method of claim 17, wherein, The step of forming the intermediate layer includes setting a second self-standing membrane on the release film.

20. The method of claim 17, wherein, The amount of the first binder in the first active material layer is equal to or less than 5 wt% relative to the total weight of the first active material layer.

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