Positive electrode slurry for all-solid-state batteries and method for manufacturing the same, and all-solid-state batteries manufactured using the same

Abstract

The present invention provides a positive electrode slurry with improved adhesive properties and a method for producing the same. [Solution] The present invention relates to a positive electrode slurry for all-solid-state batteries, a method for manufacturing the same, and an all-solid-state battery manufactured using the same, and more specifically, comprises a positive electrode active material, a conductive material, a binder, a sulfide-based solid electrolyte, a phosphine-based additive represented by the above-mentioned chemical formula 1, and a solvent.

Description

[Technical Field]

[0001] This invention relates to a positive electrode slurry for all-solid-state batteries, a method for manufacturing the same, and an all-solid-state battery manufactured using the same. [Background technology]

[0002] Recently, industrial demands have led to active development of batteries with high energy density and safety. For example, lithium-ion batteries are being used not only in the fields of information-related equipment and communication equipment, but also in the automotive sector. In the automotive sector, safety is especially important because it is related to human life.

[0003] Recently, all-solid-state batteries, which replace the electrolyte with a solid electrolyte, have been proposed. By not using a flammable organic dispersion medium, all-solid-state batteries can significantly reduce the possibility of fire or explosion even if a short circuit occurs. Therefore, such all-solid-state batteries can be made much safer than lithium-ion batteries that use an electrolyte. [Overview of the project] [Problems that the invention aims to solve]

[0004] The problem that this invention aims to solve is to provide a positive electrode slurry with improved adhesive properties and a method for producing the same.

[0005] Another problem that the present invention aims to solve is to provide a positive electrode for a solid-state battery with excellent performance and a solid-state battery containing the same. [Means for solving the problem]

[0006] A positive electrode slurry for an all-solid-state battery according to one embodiment of the present invention may contain a positive electrode active material, a conductive material, a binder, a sulfide-based solid electrolyte, a phosphine-based additive represented by the following chemical formula 1, and a solvent.

[0007] [ka]

[0008] In the aforementioned chemical formula 1, Each of the aforementioned n1 to n3 is independently 0 to 5. Each of the above R1 to R3 can independently be a hydrogen atom, a halogen group, a nitrile group, a nitro group, an amine group, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C1 to C10 alkoxy group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted C5 to C14 heteroaryl group.

[0009] A method for producing a positive electrode slurry for an all-solid-state battery according to another embodiment of the present invention may include mixing a positive electrode active material, a conductive material, a binder, a sulfide-based solid electrolyte, a phosphine-based additive represented by the following chemical formula 1, and a solvent.

[0010] [ka]

[0011] In the aforementioned chemical formula 1, Each of the aforementioned n1 to n3 is independently 0 to 5. Each of the above R1 to R3 can independently be a hydrogen atom, a halogen group, a nitrile group, a nitro group, an amine group, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C1 to C10 alkoxy group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted C5 to C14 heteroaryl group.

[0012] A solid-state battery according to another embodiment of the present invention includes a positive electrode, a negative electrode, and a solid electrolyte layer between the positive and negative electrodes, wherein the positive electrode 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 can be formed using a positive electrode slurry produced by the manufacturing method described above. [Effects of the Invention]

[0013] A method for manufacturing a positive electrode slurry for all-solid-state batteries according to one embodiment of the present invention can provide a positive electrode slurry with improved adhesive properties.

[0014] The present invention can provide a positive electrode with excellent performance and an all-solid-state battery containing the same by applying the above-described positive electrode slurry. [Brief explanation of the drawing]

[0015] [Figure 1] This is a cross-sectional view of an all-solid-state battery according to one embodiment of the present invention. [Figure 2] This is a cross-sectional view of an all-solid-state battery according to another embodiment of the present invention. [Figure 3] This is a plan view of an all-solid-state battery according to another embodiment of the present invention. [Figure 4] This is a cross-sectional view of an all-solid-state battery according to another embodiment of the present invention. [Figure 5] This is a cross-sectional view of an all-solid-state battery according to another embodiment of the present invention. [Figure 6] This is a cross-sectional view of an all-solid-state battery including a gasket structure according to another embodiment of the present invention. [Figure 7] This is an enlarged view illustrating the positive electrode active material layer according to an embodiment of the present invention. [Figure 8] This shows the results of evaluating the bending strength of the positive electrode in the examples and comparative examples. [Figure 9A] This shows the results of evaluating the bending strength of the positive electrode in the examples and comparative examples. [Figure 9B] This shows the results of evaluating the bending strength of the positive electrode in the examples and comparative examples. [Figure 9C] This shows the results of evaluating the bending strength of the positive electrode in the examples and comparative examples. [Modes for carrying out the invention]

[0016] To fully understand the structure and effects of the present invention, preferred embodiments will be described with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and can be realized in various forms and modified in various ways. These embodiments are provided solely to ensure that the disclosure of the present invention is complete and to fully inform those with ordinary skill in the art of which the invention pertains.

[0017] In this specification, when a given component is referred to as being on another component, it means that it can be formed directly on the other component or that a third component may be interposed between them. Furthermore, in the drawings, the thickness of components is exaggerated for the sake of efficient illustration of the technical content. Parts represented by the same reference number throughout the specification indicate the same component.

[0018] The embodiments described herein are explained with reference to cross-sectional and / or plan views, which are ideal illustrative representations of the invention. In the drawings, the thicknesses of films and regions are exaggerated for the efficient explanation of the technical content. Therefore, the regions illustrated in the drawings have schematic attributes, and the shapes of the regions illustrated in the drawings are for illustrative purposes only of the specific shape of the region of the device and are not intended to limit the scope of the invention. In the various embodiments herein, terms such as first, second, third, etc., have been used to describe various components, but these components should not be limited by such terms. These terms are used merely to distinguish certain components from others. The embodiments described and illustrated herein also include complementary embodiments.

[0019] The terms used herein are for illustrative purposes only and are not intended to limit the invention. In this specification, the singular form includes the plural form unless otherwise specified. The secondary battery configurations referred to as “comprises” and / or “comprising” in this specification do not preclude the presence or addition of one or more other components.

[0020] In this specification, “these combinations” may mean mixtures, laminates, composites, copolymers, alloys, blends, and reaction products of the constituents.

[0021] Unless otherwise defined herein, particle size can be the average particle size. Also, particle size refers to the average particle size (D) where the cumulative volume of the particle is 50% by volume in the particle size distribution. 50 ) means average particle size (D 50 The measurement can be performed by methods widely known to those skilled in the art, for example, by measuring with a particle size analyzer, or by measuring with a transmission electron microscope or scanning electron microscope. Alternatively, the measurement can be performed using a measuring device that utilizes dynamic light scattering, and after performing data analysis to count the number of particles for each particle size range, the average particle size (D) can be calculated from this data. 50 The ) value can be obtained. Alternatively, it can be measured using the laser diffraction method. More specifically, when measuring by laser diffraction, the particles to be measured are dispersed in a dispersion medium, then introduced into a commercially available laser diffraction particle size analyzer (for example, Microtrac MT 3000), and ultrasonic waves of approximately 28 kHz are irradiated at an output of 60 W, and the average particle size (D) at the 50% reference of the particle size distribution in the measuring device is obtained. 50 It is possible to calculate ).

[0022] Figure 1 is a cross-sectional view of an all-solid-state battery 10 according to one embodiment of the present invention.

[0023] Referring to Figure 1, an all-solid-state battery 10 according to one embodiment may include a positive electrode layer 100, a negative electrode layer 200 facing the positive electrode layer 100, and a solid electrolyte layer 300 disposed between the positive electrode layer 100 and the negative electrode layer 200. However, it is not limited thereto, and the all-solid-state battery 10 may further include additional functional layers, such as adhesion-enhancing layers, disposed 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.

[0024] In one embodiment, the positive electrode layer 100 may include a positive electrode current collector 110 and a positive electrode active material layer 120 disposed on the positive electrode current collector 110. The positive electrode active material layer 120 may include a positive electrode active material, a sulfide-based solid electrolyte, a conductive material, a binder, and a phosphine-based additive.

[0025] The positive electrode current collector 110 can provide a reference surface on which the positive electrode active material layer 120 is placed. The positive electrode current collector 110 may include a plate or foil containing, for example, indium (In), copper (Cu), magnesium (Mg), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), zinc (Zn), aluminum (Al), germanium (Ge), lithium (Li), or alloys thereof.

[0026] On the other hand, unlike the one shown in Figure 1, the positive electrode current collector 110 can be omitted in one embodiment of the present invention. Although not shown, a carbon layer with a thickness of 0.1 μm to 4 μm may be further arranged between the positive electrode current collector 110 and the positive electrode active material layer 120 to increase the bonding force between the positive electrode current collector 110 and the positive electrode active material layer 120.

[0027] The positive electrode layer 100 of the all-solid-state battery 10 according to this embodiment can be manufactured using a positive electrode slurry described later. The positive electrode layer 100 can be manufactured using conventional techniques for manufacturing electrodes, and is not particularly limited. Specifically, the positive electrode slurry described later can be applied to the positive electrode current collector 110 using methods such as a doctor blade, spray, bar coating, or slot die coating, dried, and then pressed to manufacture the electrode. The positive electrode active material layer 120 can be formed from the positive electrode slurry.

[0028] The positive electrode active material layer 120 will be described in detail later with reference to Figure 7.

[0029] Referring to Figure 1, the negative electrode layer 200 may include a negative electrode current collector 210 and a coating layer 220 disposed on the negative electrode current collector 210. The coating layer 220 may include a negative electrode active material and a binder.

[0030] The negative electrode current collector 210 can provide a reference surface on which the coating layer 220 is placed. The negative electrode current collector 210 may include, for example, a material that does not react with lithium, i.e., does not form any alloys or compounds with lithium. Examples of materials constituting the negative electrode current collector 210 include copper (Cu), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), and nickel (Ni), but are not necessarily limited to these; any material that can be used as a current collector can be used. The thickness of the negative electrode current collector 210 may be 1 μm to 20 μm, for example 5 μm to 15 μm, or for example 7 μm to 10 μm.

[0031] The negative electrode current collector 210 may be composed of one of the above-mentioned metals, or may include an alloy or coating material of two or more metals. The negative electrode current collector 210 may be, for example, in the form of a plate or foil. On the other hand, in one embodiment, the negative electrode current collector 210 may be omitted.

[0032] The coating layer 220 allows lithium metal to grow between the all-solid-state battery 10 and the negative electrode current collector 210 during charging. The coating layer 220 acts as a protective layer for the lithium metal while simultaneously suppressing the deposition and growth of lithium dendrites.

[0033] The coating layer 220 may contain metals and carbon. For example, the coating layer 220 may contain at least one metal selected from the group consisting of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn). The coating layer 220 may contain at least one carbon selected from the group consisting of carbon black, acetylene black, furnace black, ketjen black, and graphene. In one embodiment, the coating layer 220 may contain a mixture of carbon black and silver (Ag).

[0034] The coating layer 220 may further contain other additives in addition to metal and carbon. The coating layer 220 may further contain at least one additive selected from the group consisting of, for example, binders, fillers, coating agents, dispersants, and ion conductivity enhancers.

[0035] The coating layer 220 may be thinner than the positive electrode active material layer 120. The thickness of the coating layer 220 may be, for example, 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, or 5% or less of the thickness of the positive electrode active material layer 120. The thickness of the coating layer 220 may be, for example, 1 μm to 20 μm, 2 μm to 10 μm, or 3 μm to 7 μm. If the thickness of the coating layer 220 is excessively thin, lithium dendrites formed between the coating layer 220 and the negative electrode current collector 210 may cause the coating layer 220 to break down, degrading the cycle characteristics of the all-solid-state battery 10. If the thickness of the coating layer 220 is excessively increased, the energy density of the all-solid-state battery 10 will decrease, the internal resistance of the all-solid-state battery 10 due to the coating layer 220 will increase, and the cycle characteristics of the all-solid-state battery 10 may deteriorate.

[0036] On the other hand, although not shown in the diagram, a carbon layer may be further included between the coating layer 220 and the solid electrolyte layer 300 to improve adhesion.

[0037] Referring to Figure 1, the solid electrolyte layer 300 is positioned between the positive electrode layer 100 and the negative electrode layer 200 and may contain a sulfide-based solid electrolyte with excellent lithium-ion conductivity characteristics. The solid electrolyte contained in the solid electrolyte layer 300 may be the same as, or different from, any of the materials that can be contained in the solid electrolyte contained in the positive electrode active material layer 120, which will be described later.

[0038] The solid electrolyte layer 300 of one embodiment may contain a solid electrolyte. The solid electrolyte can be manufactured by processing starting materials such as Li2S and P2S5 by methods such as melt-quenching or mechanical milling. After such processing, heat treatment can be performed. The solid electrolyte may be amorphous, crystalline, or a mixture of both. The solid electrolyte may also be, for example, one of the sulfide-based solid electrolyte materials described above that contains at least sulfur (S), phosphorus (P), and lithium (Li) as constituent elements. For example, a sulfide-based solid electrolyte may be a material containing Li2S-P2S5. When using a sulfide-based solid electrolyte material containing Li2S-P2S5 to form the solid electrolyte, the molar ratio of Li2S and P2S5 is, for example, in the range of Li2S:P2S5 = 50:50 to 90:10.

[0039] Sulfide-based solid electrolytes include Li 7-a M a PS 6-c X c The compound may be an argyrodite-type compound containing (0≦a≦2, 0≦c≦2), where X may be F, Br, Cl, I, or a combination thereof. M may be 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 It may be um (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), or a combination thereof.

[0040] Sulfide-based solid electrolytes include, for example, Li 7-x PS 6-x Cl x (0 ≦ x ≦ 2), Li 7-x PS 6-x Br x (0 ≦ x ≦ 2), and Li 7-x PS 6-x I x (0 ≦ x ≦ 2) and may be an Argyrodite-type compound containing one or more selected therefrom. In particular, the sulfide-based solid electrolyte may be an Argyrodite-type compound containing one or more selected from Li6PS5Cl, Li6PS5Br, and Li6PS5I.

[0041] The density of the Argyrodite-type solid electrolyte can be 1.5 g / cc to 2.0 g / cc. By having a density of 1.5 g / cc or more for the Argyrodite-type solid electrolyte, the internal resistance of the all-solid-state battery can be reduced, and it is possible to prevent defects such as penetration and short-circuiting of the solid electrolyte film due to the formation of lithium dendrites. The elastic modulus of the solid electrolyte can be, for example, 15 GPa to 35 GPa.

[0042] The solid electrolyte layer 300 can further contain a binder. The binder contained in the solid electrolyte layer 300 is, for example, styrene styrene rubber (SBR), polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, etc., but is not limited thereto. The binder of the solid electrolyte layer 300 can be the same as or different from the binder contained in the positive electrode active material layer 120 or the binder contained in the coating layer 220.

[0043] FIG. 2 is a cross-sectional view of an all-solid-state battery 10 according to another embodiment of the present invention.

[0044] Referring to FIG. 2, the solid electrolyte layer 300 can include a first solid electrolyte layer 310 and a second solid electrolyte layer 320. The first solid electrolyte layer 310 can be adjacent to the positive electrode layer 100, and the second solid electrolyte layer 320 can be adjacent to the negative electrode layer 200.

[0045] The first solid electrolyte layer 310 and the second solid electrolyte layer 320 may have different thicknesses. The first solid electrolyte layer 310 may have a first thickness TK1, and the second solid electrolyte layer 320 may have a second thickness TK2. The first thickness TK1 may be greater than the second thickness TK2. For example, the first thickness TK1 may be 2 to 100 times the second thickness TK2.

[0046] Figure 3 is a plan view of an all-solid-state battery 10 according to another embodiment of the present invention. Figure 4 is a cross-sectional view along the line A-A' in Figure 3. In this embodiment, detailed explanations of technical features that overlap with those previously described with reference to Figures 1 and 2 are omitted, and the differences are described in detail.

[0047] Referring to Figures 3 and 4, the areas of the positive electrode layer 100 and the negative electrode layer 200 can be different from each other. Specifically, the area of ​​the negative electrode layer 200 may be larger than the area of ​​the positive electrode layer 100. The positive electrode layer 100 can completely overlap the negative electrode layer 200.

[0048] In one embodiment of the present invention, the first solid electrolyte layer 310 may have substantially the same area as the positive electrode layer 100. The second solid electrolyte layer 320 may have substantially the same area as the negative electrode layer 200.

[0049] Specifically, the first solid electrolyte layer 310 may have a first width WI1 in the first direction D1. The second solid electrolyte layer 320 may have a second width WI2 in the first direction D1. The first width WI1 may be smaller than the second width WI2. The first solid electrolyte layer 310 may have a third width WI3 in the second direction D2. The second solid electrolyte layer 320 may have a fourth width WI4 in the second direction D2. The third width WI3 may be smaller than the fourth width WI4.

[0050] The all-solid-state battery 10 according to this embodiment can be manufactured by forming a first laminate of a positive electrode layer 100 and a first solid electrolyte layer 310, forming a second laminate of a negative electrode layer 200 and a second solid electrolyte layer 320, and then laminating the first and second laminates.

[0051] Figure 5 illustrates an all-solid-state battery according to another embodiment of the present invention and is a cross-sectional view along the line A-A' in Figure 3.

[0052] Referring to Figure 5, the negative electrode layer 200 of the all-solid-state battery 10 may further include a lithium metal layer 400 between the negative electrode current collector 210 and the coating layer 220. The thickness of the lithium metal layer 400 may further increase when the all-solid-state battery 10 is charged. The coating layer 220 performs a protective layer role for the lithium metal layer 400 and at the same time can suppress the growth of lithium dendrites from the lithium metal layer 400.

[0053] The lithium metal layer 400 may be a thin metal film containing lithium or a lithium alloy. Examples of lithium alloys include, but are not limited to, Li-Al alloys, Li-Sn alloys, Li-In alloys, Li-Ag alloys, Li-Au alloys, Li-Zn alloys, Li-Ge alloys, and Li-Si alloys; any alloy that can be used with lithium is acceptable. The lithium metal layer 400 may contain one of these alloys or lithium. Alternatively, the lithium metal layer 400 may contain various types of alloys.

[0054] The lithium metal layer 400 may have a fifth width WI5 in the first direction D1. The fifth width WI5 may be the same as or larger than the first width WI1. The fifth width WI5 may be the same as or smaller than the second width WI2. For example, the fifth width WI5 may be larger than the first width WI1 and smaller than the second width WI2.

[0055] Figure 6 is a cross-sectional view illustrating an all-solid-state battery 10 according to another embodiment of the present invention.

[0056] Referring to Figure 6, the all-solid-state battery 10 can include a gasket structure 500. The gasket structure 500 can fill the step difference on the side surface of the all-solid-state battery 10 caused by the area difference between the first and second layers.

[0057] Referring to Figure 3, the gasket structure 500 can surround the sides of the first stack of the all-solid-state battery 10 along the first and second directions D1 and D2. As an example, the thickness of the gasket structure 500 may be substantially the same as the thickness of the first stack. Therefore, even if the area of ​​the other first and second stacks is stacked and pressed, damage to the steps on the sides of the all-solid-state battery can be prevented. "Substantially the same thickness" can be defined as a thickness sufficient to prevent damage to the steps on the sides of the all-solid-state battery even if the area of ​​the other first and second stacks is stacked and pressed.

[0058] Cathode active material layer Figure 7 is an enlarged cross-sectional view of a portion of the positive electrode active material layer 120 (see Figure 1) according to an embodiment of the present invention. In Figure 7, the M region of Figure 1 is shown in an enlarged view.

[0059] Referring to Figure 7, the positive electrode active material layer 120 according to the present invention may include a positive electrode active material CAM, a conductive material CDM, a binder BID, a sulfide-based solid electrolyte SEL, a phosphine-based additive PHA, and a binder modifier BMD. The positive electrode active material layer 120 may be manufactured by coating a positive electrode slurry, described later, onto a positive electrode current collector 110.

[0060] The positive electrode active material CAM is a substance capable of reversibly absorbing and desorbing lithium ions. The positive electrode active material CAM may include, but is not limited to, lithium transition metal oxides such as 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, lithium iron phosphate, nickel sulfide, copper sulfide, lithium sulfide, iron oxide, or vanadium oxide. Each positive electrode active material may be a single material or a mixture of two or more materials.

[0061] Lithium transition metal oxides include, for example, Li a A 1-b B b D2(0.90≦a≦1, 0≦b≦0.5), Li a E 1-b B b O 2-c D c (0.90≦a≦1, 0≦b≦0.5, 0≦c≦0.05), LiE 2-b B b O 4-c D c (0≦b≦0.5, 0≦c≦0.05), Li a Ni 1-b-c Co b B c D α (0.90≦a≦1, 0≦b≦0.5, 0≦c≦0.05, 0<α<2), Li a Ni 1-b-c Co b B c O 2-α F α (0.90≦a≦1, 0≦b≦0.5, 0≦c≦0.05, 0<α<2), Li a Ni 1-b-c Mn b B c D α(0.90≦a≦1、0≦b≦0.5、0≦c≦0.05、0<α≦2)、Li a Nor 1-b-c Mn b B c O 2-α F α (0.90≦a≦1、0≦b≦0.5、0≦c≦0.05、0<α<2)、Li a Nor b E c G d O2(0.90≦a≦1、0≦b≦0.9、0≦c≦0.5、0.001≦d≦0.1)、Li a Nor b Co c Mn d GeO2(0.90≦a≦1、0≦b≦0.9、0≦c≦0.5、0≦d≦0.5、0.001≦e≦0.1)、Li a NiG b O2(0.9≦a≦1、0.001≦b≦0.1)、Li a CoG b O2(0.90≦a≦1、0.001≦b≦0.1)、Li a MnG b O2(0.90≦a≦1、0.001≦b≦0.1)、Li a Mn2GbO4(0.90≦a≦1、0.001≦b≦0.1),QO2、QS2、LiQS2、V2O5、LiV2O5、LiIO2、LiVO4、Li 3-f J2(PO4)3(0≦f≦2)、Li 3-fThis compound is represented by one of the following: Fe2(PO4)3 (0≦f≦2) or LiFePO4. In such a compound, capital letter "A" is Ni, Co, Mn, or a combination thereof; capital letter "B" is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof; capital letter "D" is O, F, S, P, or a combination thereof; capital letter "E" is Co, Mn, or a combination thereof; capital letter "F" is F, S, P, or a combination thereof; capital letter "G" is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; capital letter "Q" is Ti, Mo, Mn, or a combination thereof; capital letter "I" is Cr, V, Fe, Sc, Y, or a combination thereof; and capital letter "J" may be V, Cr, Mn, Co, Ni, Cu, or a combination thereof.

[0062] The positive electrode active material CAM may include, for example, lithium salts of transition metal oxides having a layered rock salt type structure among the lithium transition metal oxides mentioned above. "Layered rock salt type structure" refers to, for example, a cubic rock salt type structure. <111> The structure may consist of alternating, regular arrangements of oxygen and metal atomic layers in a directional pattern, where each atomic layer forms a two-dimensional plane. The "cubic rock salt type structure" exhibits a sodium chloride type (NaCl type) structure, a type of crystal structure, and specifically, it can represent a structure in which the face-centered cubic lattices (fcc) formed by the cations and anions are offset from each other by about half the ridge length of the unit lattice. Lithium transition metals and oxides having such a layered rock salt type structure include, for example, LiNi x Co y Al z O2(NCA) or LiNi x Co y Mn zIt can be a ternary lithium transition metal oxide such as O2(NCM) (0 < x < 1, 0 < y < 1, 0 < z < 1, x + y + z = 1). When the positive electrode active material CAM contains a ternary lithium transition metal oxide having a layered rock salt structure, the energy density of the all-solid-state battery 10 increases and the thermal stability can be improved.

[0063] The above-described compound contained in the positive electrode active material CAM may be covered by a coating layer (not shown). The positive electrode active material CAM can be used by mixing the above-described compound and the compound with the coating layer added. On the other hand, the coating layer added to the surface of the positive electrode active material CAM can contain, for example, oxides, hydroxides, oxyhydroxides, oxycarbonates, or hydroxycarbonates of the following coating elements. The compound forming such a coating layer can be amorphous or crystalline. The coating elements contained in the coating layer can include Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, or a mixture thereof. The coating layer can contain, for example, Li2O-ZrO2 (LZO) or the like. The coating layer forming method can be selected within a range that does not adversely affect the physical properties of the positive electrode active material CAM. The coating layer forming method can be, for example, spray coating, dipping method, or the like.

[0064] When the positive electrode active material CAM contains nickel (Ni) as a ternary lithium transition metal oxide such as NCA or NCM, for example, the capacity density of the all-solid-state battery 10 can be increased and the metal elution of the positive electrode active material CAM in the charged state can be reduced. As a result, the cycle characteristics of the all-solid-state battery 10 in the charged state can be improved. On the other hand, the "cycle characteristics" is a characteristic indicating the degree to which the all-solid-state battery 10 deteriorates due to charge / discharge of the all-solid-state battery 10. An all-solid-state battery 10 with high cycle characteristics has a small degree of deterioration of the all-solid-state battery 10 due to charge / discharge, and an all-solid-state battery 10 with low cycle characteristics may have a large degree of deterioration of the all-solid-state battery 10 due to charge / discharge.

[0065] The shape of the positive electrode active material CAM can include particle shapes such as spheres and ellipsoids. The particle size and content of the positive electrode active material CAM are not particularly limited.

[0066] The positive electrode active material layer 120 may contain 75 to 95 parts by weight of positive electrode active material CAM, based on 100 parts by weight of the total of positive electrode active material CAM, conductive material CDM, and binder BID.

[0067] The positive electrode active material layer 120 may include a conductive material CDM. The conductive material CDM may have conductivity without causing a chemical change in the all-solid-state battery 10 and may enhance the conductivity of the positive electrode active material CAM and the sulfide-based solid electrolyte SEL.

[0068] The conductive material CDM may contain carbon-based materials. The conductive material CDM may contain one or more selected from, for example, graphite, carbon black, acetylene black, carbon nanofibers, and carbon nanotubes.

[0069] The positive electrode active material layer 120 may contain 0.05 parts by weight or more and 5 parts by weight or less of conductive material CDM, based on 100 parts by weight of the total positive electrode active material CAM, conductive material CDM, and binder BID.

[0070] The positive electrode active material layer 120 may contain a sulfide-based solid electrolyte SEL.

[0071] Sulfide-based solid electrolytes (SELs) can have a particulate shape. Sulfide-based solid electrolytes (SELs) may also be dispersed between positive electrode active materials (CAMs). Examples of sulfide-based solid electrolytes (SELs) with excellent lithium-ion conductivity characteristics include Li2S-P2S5, Li2S-P2S5-LiX (where X is 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 Sn (m, n are positive numbers, and the capital letter "Z" is one of Ge, Zn, or Ga), Li2S - GeS2, Li2S - SiS2 - Li3PO4, Li2S - SiS2 - Li p MO q (p, q are positive numbers, and the capital letter "M" is one of P, Si, Ge, B, Al, GaIn), Li 7-x PS 6-x Cl x (0 ≤ x ≤ 2), Li 7-x PS 6-x Br x (0 ≤ x ≤ 2), and Li 7-x PS 6-x I x (0 ≤ x ≤ 2) can include at least one selected from the above.

[0072] The sulfide - based solid electrolyte SEL is, for example, Li 7-x PS 6-x Cl x (0 ≤ x ≤ 2), Li 7-x PS 6-x Br x (0 ≤ x ≤ 2), and Li 7-x PS 6-x I x (0 ≤ x ≤ 2) can be an Argyrodite - type compound containing one or more selected from the above. In particular, the sulfide - based solid electrolyte can be an Argyrodite - type compound containing one or more selected from Li6PS5Cl, Li6PS5Br, and Li6PS5I.

[0073] The sulfide - based solid electrolyte SEL is Li 7-a M a PS 6-c X cThe compound may be an argyrodite-type compound containing (0≦a≦2, (0≦c≦2)), where X may be F, Br, Cl, or a combination thereof. M may be 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 It may be um (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), or a combination thereof.

[0074] The density of the argyrodite-type solid electrolyte can be 1.5 g / cc to 2.0 g / cc. Having a density of 1.5 g / cc or higher for the argyrodite-type solid electrolyte reduces the internal resistance of the all-solid-state battery 10, preventing defects such as penetration and short circuits of the solid electrolyte membrane due to lithium dendrite formation.

[0075] The elastic modulus of the sulfide-based solid electrolyte SEL may be, for example, 15 GPa to 35 GPa. The sulfide-based solid electrolyte SEL may be the same as the solid electrolyte contained in the solid electrolyte layer 300 described above.

[0076] The sulfide-based solid electrolyte SEL contained in the positive electrode active material layer 120 has a medium average particle size (D) compared to the solid electrolyte contained in the solid electrolyte layer 300. 50 The intermediate particle size (D) of the sulfide-based solid electrolyte SEL contained in the positive electrode active material layer 120 may be small. 50 ) is the average particle size (D) of the solid electrolyte contained in the solid electrolyte layer 300. 50) may be 90% or less, 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, or 20% or less. On the other hand, the average particle size of the intermediate particle size (D 50 ) can be the median diameter measured using a laser particle size analyzer.

[0077] Average particle size (D) of sulfide-based solid electrolyte SEL 50 The average particle size (D) of the solid electrolyte SEL may be, for example, 1 μm or less, 0.9 μm or less, 0.5 μm or less, or 0.1 μm or less. 50 ) may be, for example, 10 nm to 1 μm, 10 nm to 0.9 μm, or 10 nm to 0.1 μm.

[0078] The positive electrode active material layer 120 may contain 5 to 25 parts by weight of a sulfide-based solid electrolyte SEL, relative to 100 parts by weight of the total positive electrode active material CAM, conductive material CDM, and binder BID.

[0079] The positive electrode active material layer 120 may contain a binder BID. The binder BID may contain a substance that binds the positive electrode active material CAM, sulfide-based solid electrolyte SEL, and conductive material CDM contained in the positive electrode active material layer 120, and improves the bonding strength with the positive electrode current collector 110.

[0080] Binder BID can contain fluoride-based binders.

[0081] The fluoride binder may include, for example, at least one of polyvinylidene fluoride, polyvinylidene fluoride-co-hexafluoropropylene (PVdF-HFP), polyvinylidene fluoride-co-trichloroethylene, polyvinylidene fluoride-co-tetrafluoroethylene, polyvinylidene fluoride-co-trifluoroethylene, polyvinylidene fluoride-co-trifluorochloroethylene, polyvinylidene fluoride-co-ethylene fluoride-hexafluoropropylene, and polyvinylidene fluoride-co-trichloroethylene.

[0082] The positive electrode active material layer 120 may contain 0.5 parts by weight or more and 5 parts by weight or less of binder BID, based on 100 parts by weight of the total positive electrode active material CAM, conductive material CDM, and binder BID. If the binder BID content is below the above range, the dispersion effect of the binder BID may decrease. If the binder content exceeds the above range, the stability of the slurry phase may decrease due to the aggregation of binder BID.

[0083] On the other hand, while fluoride binders are excellent as binders for integrating materials, they do not adhere well to current collector metals such as copper. As a result, in all-solid-state batteries 10 having electrodes using the aforementioned fluoride binder, repeated charging and discharging can cause the active material and other materials to detach from the current collector, leading to a decrease in battery capacity and thus a shortened cycle life.

[0084] To solve these problems, the positive electrode active material layer 120 according to the present invention may contain a phosphine-based additive PHA.

[0085] Phosphine-based additives (PHA) can improve the manufacturing processability, stability, and performance of all-solid-state batteries.

[0086] The phosphine-based additive PHA may contain the compound represented by the following chemical formula 1.

[0087] [ka]

[0088] In the aforementioned chemical formula 1, Each of the aforementioned n1 to n3 is independently 0 to 5. Each of the above R1 to R3 can independently be a hydrogen atom, a halogen group, a nitrile group, a nitro group, an amine group, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C1 to C10 alkoxy group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted C5 to C14 heteroaryl group.

[0089] For example, phosphine-based additives PHA include triphenyl phospine, tris(4-trifluoromethylphenyl) phosphine, tris(4-fluorophenyl) phosphine, tris[3,5-bis(trifluoromethyl)phenyl]phosphine, tris(4-chlorophenyl) phosphine, tris(2,4,6-trimethylphenyl) phosphine, tris(4-methoxyphenyl) phosphine, and tris(pentafluorophenyl) phosphine. It may include at least one selected from the group consisting of phosphine, tris(4-methoxy-3,5-dimethylphenyl)phosphine, tris(3,5-dimethylphenyl)phosphine, tri(o-tolyl)phosphine, diphenyl(p-tolyl)phosphine, or combinations thereof.

[0090] As an example, the phosphine-based additive PHA is polysulfide (S x Triphenyl phospine, which reacts favorably with ), can be used.

[0091] The positive electrode active material layer 120 may contain 0.01 parts by weight or more and 3 parts by weight or less of the phosphine-based additive PHA, based on 100 parts by weight of the total positive electrode active material CAM, conductive material CDM, and binder BID. If the amount of phosphine-based additive PHA is excessive, the resistance of the electrode plate may increase and performance may deteriorate. By satisfying the above numerical range, the manufacturing processability, stability, capacity, and other performance aspects of the positive electrode active material layer 120 can be comprehensively improved.

[0092] The weight ratio of the phosphine-based additive PHA to the sulfide-based solid electrolyte SEL can be 0.2 to 25. For example, the weight ratio of the phosphine-based additive PHA to the sulfide-based solid electrolyte SEL can be 0.3 to 24, 0.4 to 23, or 0.45 to 22.5. If the weight ratio is too low, deviating from the above range, it will be difficult to obtain the product formed by the reaction with the sulfide-based solid electrolyte SEL. If the weight ratio is too high, an excess of unreacted material may remain in the positive electrode active material layer 120. In addition, slurry gelation may occur, resulting in the generation of a large amount of electrode plate manufacturing spray.

[0093] By having the aforementioned weight ratio of the sulfide-based solid electrolyte SEL and the phosphine-based additive PHA, a sufficient amount of the binder modifier BMD, described later, can be secured within the positive electrode active material layer 120.

[0094] In one embodiment, the positive electrode active material layer 120 may contain a binder modifier BMD.

[0095] The binder modifier BMD may be a product obtained by reacting a phosphine-based additive PHA with an eluent from a sulfide-based solid electrolyte SEL.

[0096] By including the phosphine-based additive PHA within a specific content range in the positive electrode active material layer 120, it can optimally react with the eluted substances of the sulfide-based solid electrolyte SEL to obtain the binder modifier BMD.

[0097] Sulfide-based solid electrolytes (SELs) are dissolved in a polar solvent during a wet process, and alkali metals, sulfides, and other component elements contained in the sulfide-based solid electrolytes (SELs) can escape from the surface of the SEL as eluted substances. At this time, the phosphine-based additive PHA according to the present invention may react with sulfides that are unstable in the atmosphere and polar solvents among the sulfide-based eluted substances to produce a binder modifier BMD.

[0098] The binder modifier BMD, produced by the reaction of the phosphine-based additive PHA with a sulfide-based eluent, may be a sulfide-based substance.

[0099] As an example, the binder modifier BMD is triphenylphosphine sulfide (C18H 15 It may include at least one selected from the group consisting of PS), phosphate sulfide, lithium sulfide (Li2S), or combinations thereof.

[0100] The positive electrode active material layer 120 may contain 0.0001 parts by weight or more and 1 part by weight or less of a binder modifier BMD, based on 100 parts by weight of the total positive electrode active material CAM, conductive material CDM, and binder BID.

[0101] During the reaction of the phosphine-based additive PHA with the sulfide-based eluent to produce the binder modifier BMD, radicals are generated. These radicals interact with the binder BID to modify the structure of the fluoride-based binder, thereby improving its adhesive performance. Consequently, the modified fluoride-based binder exhibits strong adhesive force, allowing the positive electrode active material to be firmly bonded to the metal current collector.

[0102] In addition to the positive electrode active material CAM, conductive material CDM, binder BID, sulfide-based solid electrolyte SEL, phosphine-based additive PHA, and binder modifier BMD mentioned above, the positive electrode active material layer 120 may further contain additives such as fillers, coating agents, dispersants, and ion conductivity enhancers.

[0103] The positive electrode active material layer 120 can be manufactured, for example, by providing a mixture in which the materials constituting the positive electrode active material layer 120 are dispersed onto the positive electrode current collector 110. By including a binder BID and a phosphine-based additive PHA in the materials constituting the positive electrode active material layer 120, the adhesion strength of the positive electrode active material layer 120 can be improved while maintaining stable dispersibility.

[0104] According to one embodiment, the positive electrode active material layer 120 contains a phosphine-based additive PHA that can cause structural deformation of the binder BID, thereby increasing the adhesion characteristics between the positive electrode active material layer 120 and the positive electrode current collector 110, and improving the output characteristics and capacity of the all-solid-state battery 10.

[0105] The following describes a positive electrode slurry and a method for manufacturing the same according to one embodiment.

[0106] Positive electrode slurry and method for manufacturing the same The following describes a method for manufacturing a positive electrode slurry for all-solid-state batteries according to one embodiment.

[0107] A method for producing a positive electrode slurry for an all-solid-state battery according to one embodiment of the present invention may include mixing a positive electrode active material CAM, a conductive material CDM, a binder BID, a sulfide-based solid electrolyte SEL, a phosphine-based additive PHA, and a solvent.

[0108] A positive electrode slurry can be manufactured by placing the positive electrode active material CAM, conductive material CDM, binder BID, sulfide-based solid electrolyte SEL, phosphine-based additive PHA, and solvent into a container and mixing them.

[0109] In the aforementioned mixing method, any method that is accessible to those skilled in the art, such as wet or dry mixing, can be used, and is not limited to a specific method.

[0110] As an example, the mixing can be carried out using a mixer or kneader. In one embodiment of the present invention, mixing can be carried out using a PD mixer (Planetary Disperser mixer), a planetary mixer, a paddle mixer, a ribbon mixer, a dual shaft mixer, a high-speed impeller mixer, or a propeller mixer at 20°C to 60°C for 10 to 90 minutes.

[0111] In one embodiment of the present invention, the mixing can be performed using a PD mixer (Planetary Disperser mixer). When the mixing is performed using a PD mixer, the RPM speed may be 60 to 150.

[0112] In the method for producing a positive electrode slurry, the substances described above can be used for each of the positive electrode active material CAM, conductive material CDM, binder BID, sulfide-based solid electrolyte SEL, and phosphine-based additive PHA.

[0113] The positive electrode active material CAM according to one embodiment may be a positive electrode active material in powder form. The positive electrode active material may include, but is not limited to, lithium transition metal oxides such as 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, lithium iron phosphate, nickel sulfide, copper sulfide, lithium sulfide, iron oxide, or vanadium oxide. Each of the positive electrode active materials CAM may be a single material or a mixture of two or more.

[0114] The conductive material CDM may contain carbon-based materials. The conductive material CDM may contain one or more selected from, for example, graphite, carbon black, acetylene black, carbon nanofibers, and carbon nanotubes.

[0115] The binder BID may contain substances to improve the binding force and dispersibility between the positive electrode active material CAM and the sulfide-based solid electrolyte SEL.

[0116] A binder BID according to one embodiment may include a fluoride-based binder. The fluoride-based binder may be, for example, polyvinylidene fluoride, polyvinylidene fluoride-co-hexafluoropropylene (PVdF-HFP), polyvinylidene fluoride-co-trichloroethylene, polyvinylidene fluoride-co-tetrafluoroethylene, polyvinylidene fluoride-co-trifluoroethylene, polyvinylidene fluoride-co-trifluorochloroethylene, polyvinylidene fluoride-co-ethylene fluoride-hexafluoropropylene, or polyvinylidene fluoride-co-trichloroethylene.

[0117] A sulfide-based solid electrolyte (SEL) according to one embodiment may be in powder form. For example, a sulfide-based solid electrolyte (SEL) may contain Li 7-x PS 6-x Cl x (0≦x≦2), Li 7-x PS 6-x Br x (0≦x≦2), and Li 7-x PS 6-x I x The compound may be an argyrodite-type compound containing one or more values ​​selected from (0 ≤ x ≤ 2). In particular, the solid electrolyte may be an argyrodite-type compound containing one or more values ​​selected from Li6PS5Cl, Li6PS5Br, and Li6PS5I.

[0118] The content of the sulfide-based solid electrolyte SEL in the positive electrode slurry may be 5 to 25 parts by weight, based on 100 parts by weight of the total positive electrode active material CAM, conductive material CDM, and binder BID.

[0119] In one embodiment of the method for producing a positive electrode slurry, a phosphine-based additive PHA can be added. Since the phosphine-based additive PHA is the same as that described earlier, a detailed explanation of it will be omitted.

[0120] One embodiment of the phosphine-based additive PHA may be a compound represented by the following chemical formula 1.

[0121] [ka]

[0122] In the aforementioned chemical formula 1, Each of the aforementioned n1 to n3 is independently 0 to 5. Each of the above R1 to R3 can independently be a hydrogen atom, a halogen group, a nitrile group, a nitro group, an amine group, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C1 to C10 alkoxy group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted C5 to C14 heteroaryl group.

[0123] For example, phosphine-based additives PHA include triphenyl phospine, tris(4-trifluoromethylphenyl) phosphine, tris(4-fluorophenyl) phosphine, tris[3,5-bis(trifluoromethyl) phenyl]phosphine, tris(4-chlorophenyl) phosphine, tris(2,4,6-trimethylphenyl) phosphine, tris(4-methoxyphenyl) phosphine, and tris(pentafluorophenyl) phosphine. It may include at least one selected from the group consisting of phosphine, tris(4-methoxy-3,5-dimethylphenyl)phosphine, tri(3,5-dimethylphenyl)phosphine, tri(o-tolyl)phosphine, diphenyl(p-tolyl)phosphine, or combinations thereof.

[0124] The content of the phosphine-based additive PHA in the positive electrode slurry can be 0.01 to 3 parts by weight, based on 100 parts by weight of the total positive electrode active material CAM, conductive material CDM, and binder BID.

[0125] The solvent may include one or more solvents selected from the group consisting of ethyl acetate, hexyl butyrate, water (H2O), alcohol, formic acid, acetic acid, tetrahydrofuran, dimethylformamide, acetonitrile, dimethyl sulfoxide, acetone, ethyl acetate, dimethoxyethane, 1,3-dioxolane, N-methylpyrrolidinone, N-methylformamide, diethyl carbonate, ethylmethylcarbonate, and dimethyl carbonate.

[0126] The solvent content in the positive electrode slurry can be 15 to 50 parts by weight, based on 100 parts by weight of the total positive electrode active material CAM, conductive material CDM, and binder BID.

[0127] In one embodiment, the solvent may include ethyl acetate, which facilitates surface elution of sulfide-based solid electrolytes (SELs), or hexyl butyrate, which has a vapor pressure suitable for the slurry process.

[0128] The mixing ratio of the phosphine-based additive PHA to the sulfide-based solid electrolyte SEL in the positive electrode slurry can be 0.2 to 25 by weight. For example, the weight ratio of the phosphine-based additive PHA to the sulfide-based solid electrolyte SEL can be 0.3 to 24, 0.4 to 23, or 0.45 to 22.5.

[0129] The cathode slurry may further contain a product formed by the reaction of a phosphine-based additive PHA with an eluent from a sulfide-based solid electrolyte SEL. The product may include a binder modifier BMD.

[0130] The aforementioned "product" refers to the intermediate reaction product obtained between the solvent, the sulfide-based solid electrolyte SEL, and the phosphine-based additive PHA during the mixing process.

[0131] Binder modifier BMD can improve adhesive performance by modifying the structure of fluoride-based binders.

[0132] For example, the binder modifier BMD is triphenylphosphine sulfide (C). 18 H 15 It may include at least one selected from the group consisting of PS), phosphate sulfide, lithium sulfide (Li2S), or combinations thereof.

[0133] The content of the binder modifier BMD in the positive electrode slurry can be between 0.0001 parts by weight and 1 part by weight, based on 100 parts by weight of the total positive electrode active material CAM, conductive material CDM, and binder BID.

[0134] The positive electrode slurry produced by the above manufacturing method can be applied to the positive electrode current collector 110, dried, and then rolled to form the positive electrode active material layer 120. In one embodiment, the thickness of the positive electrode active material layer 120 may be 10 μm to 30 μm, 5 μm to 30 μm, 10 μm to 20 μm, 10 μm to 40 μm, 20 μm to 50 μm, or 40 μm to 50 μm.

[0135] In one embodiment, the positive electrode slurry can solve the problem of active material and other materials separating from the current collector during positive electrode manufacturing by adding a phosphine-based additive PHA.

[0136] As a result, the positive electrode slurry according to one embodiment can have improved electrical properties, including both dispersibility and adhesion. Therefore, an all-solid-state battery manufactured using the positive electrode slurry of the present invention can have excellent performance.

[0137] The present invention will be described in more detail below through embodiments. However, these embodiments are for illustrative purposes only, and the scope of the present invention is not limited to these embodiments.

[0138] Example 1: Production of positive electrode slurry A sulfide-based solid electrolyte (Li6PS5Cl) is added to the solvent (Octyl acetate). 0.5 Br 0.5 A mixture was prepared by adding ) and a phosphine-based additive (Triphenyl phospine, PPh3). In the prepared mixture, the content ratio of the phosphine-based additive to the sulfide-based solid electrolyte was 0.45.

[0139] Cathode active material (LiNi 0.94 Co 0.04 Al 0.02 The mixture was dispersed in 100 parts by weight of a total of O2, a binder (PVdF-HFP), and a conductive material (carbon nanotubes) to finally produce a positive electrode slurry.

[0140] The manufactured positive electrode slurry was coated onto aluminum foil and then dried at a temperature of 150°C for 2 hours to produce the positive electrode.

[0141] Example 2 The cathode slurry and cathode were manufactured in the same manner as in Example 1, except that the content ratio of the phosphine-based additive to the sulfide-based solid electrolyte was changed to 2.31.

[0142] Example 3 The cathode slurry and cathode were manufactured in the same manner as in Example 1, except that the content ratio of the phosphine-based additive to the sulfide-based solid electrolyte was changed to 6.92.

[0143] Example 4 The cathode slurry and cathode were manufactured in the same manner as in Example 1, except that the content ratio of the phosphine-based additive to the sulfide-based solid electrolyte was changed to 22.32.

[0144] Comparative Example 1 The cathode slurry and cathode were manufactured using the same method as in Example 1, except that a phosphine-based additive was not added.

[0145] Comparative Example 2 The cathode slurry and cathode were manufactured in the same manner as in Example 1, except that the content ratio of the phosphine-based additive to the sulfide-based solid electrolyte was changed to 37.20.

[0146] The compositions of the positive electrode slurries produced in the examples and comparative examples are specifically described in Table 1 below.

[0147] [Table 1]

[0148] Evaluation Example 1: Adhesion strength of the positive electrode The adhesive strength between the positive electrode active material layer and the positive electrode current collector was measured for the positive electrodes manufactured in the examples and comparative examples, and the results are shown in Table 2.

[0149] Specifically, the positive electrodes manufactured in the above-described examples and comparative examples were cut to a length of 150 mm and a width of 20 mm, and the surface of the positive electrode was attached to a glass slide measuring 75 mm in length and 25 mm in width using double-sided tape in the longitudinal direction. In other words, the glass slide was attached to an area corresponding to half the length of the positive electrode.

[0150] Next, the evaluation sample was prepared by rubbing the roller 10 times to ensure uniform adhesion of the double-sided tape. Then, the slide glass portion of the evaluation sample was fixed to the sample stage of a Universal Testing Machine (UTM) (product name: LS5, manufacturer: LLOYD), and the half of the positive electrode that could not be attached to the slide glass was connected to a load cell equipped with the UTM. The load applied to the load cell was measured while moving it 50 mm at a speed of 100 mm / min with a force applied at a 90° angle. At this time, the average value of the load measured in the 20 mm to 40 mm section of the travel distance was calculated, and this was repeated a total of 5 times. The average value was evaluated as the positive electrode adhesion strength (gf / mm) of each sample.

[0151] Evaluation Example 2: Peel Strength strength) The peel strength of the positive electrodes manufactured in the examples and comparative examples was confirmed. Specifically, the peel strength was measured by cutting the positive electrode with a blade using SAICAS (Surface And Interfacial Cutting Analysis System) equipment to separate the lower part (positive electrode current collector) and the upper part (positive electrode active material layer). The measured peel strength evaluation results are shown in Table 2 below.

[0152] Evaluation Example 3: Bending Strength strength) The bending strength (3-point bending test) of the positive electrode plates manufactured in the examples and comparative examples was measured according to the method of ASTM D790.

[0153] Specifically, the positive electrode plates manufactured in the examples and comparative examples were cut to a size of 15 mm x 20 mm to prepare test specimens. Using a three-point bending method, the test specimens were placed between the first and second points, which were 10 mm apart. A bending property test was performed by pressing the center of the specimen (third point) with a probe at a constant speed in the thickness direction of the specimen. The applied force was measured while moving the third point in the thickness direction at a speed of 5 mm / min. The measurement results are shown in Table 2 and Figure 8 below. The maximum bending force (maximum bending strength) is the maximum force applied to the specimen depending on the distance the probe was moved.

[0154] [Table 2]

[0155] As shown in Table 2, the adhesive strength and peel strength were increased in the positive electrode of the example compared to the positive electrode of the comparative example. The maximum bending strength of the positive electrode of the example was higher than that of the positive electrode of the comparative example.

[0156] Furthermore, as shown in Table 2 and Figure 8, the maximum bending strength of the positive electrode in the example is higher than that of the positive electrode in the comparative example.

[0157] Therefore, it was confirmed that the positive electrode of the example has significantly improved adhesive force between the positive electrode active material layer and the current collector compared to the positive electrode of the comparative example.

[0158] Evaluation Example 4: Cathode Loading Level (L / L, mg / cm²) 2 ) Loading level (mg / cm²) for the positive electrodes manufactured in Example 1 and Comparative Example 1 2 The following measurements were taken and the results are shown in Figures 9A and 9B.

[0159] Specifically, a circular punch with a diameter of 16 mm is used to punch out a positive electrode coated with positive electrode active material and a current collector that is not coated with active material, and then their weights are measured. The weight of the active material loaded onto the electrode is measured by subtracting the weight of the current collector that is not coated with active material from the weight of the positive electrode coated with active material, and the amount of positive electrode active material coated per unit area (loading level, mg / cm²) is calculated by dividing it by the area of ​​the coated active material. 2 ) was measured.

[0160] Next, the bending strength of the positive electrodes manufactured in Example 1 and Comparative Example 1 was gradually increased, and the resulting phenomena were observed. The results are shown in Figure 9C.

[0161] As shown in Figures 9A to 9C, the loading level of the positive electrode in this embodiment is 30 to 45 mg / cm². 2 This is possible. Furthermore, at the same bending strength, cracks occurred in the active material layer of the comparative positive electrode, but not in the example positive electrode.

[0162] Therefore, it was confirmed that the positive electrode of the embodiment has improved flexibility compared to the positive electrode of the comparative example.

[0163] Evaluation Example 5: Lifetime Characteristics of All-Solid-State Batteries The positive electrodes manufactured in the examples and comparative examples were applied to all-solid-state batteries. In this evaluation example, the cell life of the all-solid-state battery was investigated, and charging and discharging were performed using a constant current method with a charge / discharge tester.

[0164] The manufactured all-solid-state rechargeable battery was charged with a constant current at a 0.1C rate at 25°C until the voltage reached 3.63V (vs. Li-In). Subsequently, it was cut off with a current of 0.05C rate while maintaining 3.63V in constant voltage mode. Then, during discharge, it was discharged with a constant current at a 0.1C rate until the voltage reached 1.88V (vs. Li-In) (1st cycle). This cycle was repeated under the same conditions for 50 cycles.

[0165] A 10-minute downtime was observed after each charge / discharge cycle in all charge / discharge cycles. The results of the high-temperature charge / discharge experiments are shown in Table 3 below. The capacity retention rate is defined by Equation 1 below. [Formula 1] Capacity retention rate [%] = [Discharge capacity at 50th cycle / Discharge capacity at 1st cycle] × 100

[0166] [Table 3]

[0167] As shown in Table 3, it can be seen that the all-solid-state battery using the positive electrode according to the embodiment of the present invention exhibits improved cycle characteristics and lifespan compared to the comparative example.

[0168] Therefore, the all-solid-state battery to which the positive electrode slurry described in the claims of the present invention is applied shows improved discharge capacity compared to the comparative example due to improved adhesion between the positive electrode current collector and the positive electrode active material layer, and stable contact between the positive electrode current collector and the positive electrode active material layer is maintained without detachment of the positive electrode active material even when charging and discharging are repeated in the cycle, resulting in improved capacity retention.

[0169] Although embodiments of the present invention have been described above with reference to the attached drawings, the present invention may be implemented in other specific forms without changing its technical concept or essential features. Therefore, the embodiments described above should be understood to be illustrative and not limiting in all respects. [Explanation of Symbols]

[0170] BID Binder BMD Binder Modifier CAM positive electrode active material CDM conductive material PHA phosphine-based additives SEL Sulfide solid electrolyte

Claims

1. Positive electrode active material and, conductive material, Binder and, Sulfide-based solid electrolytes, A phosphine-based additive represented by the following chemical formula 1, Solvent and, A positive electrode slurry for all-solid-state batteries, including the above. 【Chemistry 1】 (In the above chemical formula 1, The aforementioned n 1 〜n 3 Each of them is independently between 0 and 5. The aforementioned R 1 ~R 3 Each of these is independently a hydrogen atom, a halogen group, a nitrile group, a nitro group, an amine group, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C1 to C10 alkoxy group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted C5 to C14 heteroaryl group.

2. The phosphine-based additives include triphenylphosphine, tris(4-trifluoromethylphenyl)phosphine, tris(4-fluorophenyl)phosphine, tris[3,5-bis(trifluoromethyl)phenyl]phosphine, and tris(4-chlorophenyl)phosphine. Tris(2,4,6-trimethylphenyl)phosphine, Tris(4-methoxyphenyl)phosphine, Tris(4-methoxyphenyl)phosphine, Tris(pentafluorophenyl)phosphine, Tris(4-methoxy-3,5-dimethylphenyl)phosphine, Tris(3,5-dimethylphenyl)phosphine It includes at least one selected from the group consisting of phosphine, tri(o-tolyl)phosphine, diphenyl(p-tolyl)phosphine, or combinations thereof. The positive electrode slurry for an all-solid-state battery according to claim 1.

3. The content of the phosphine-based additive is 0.01 to 3 parts by weight per 100 parts by weight of the total of the positive electrode active material, the conductive material, and the binder. The positive electrode slurry for an all-solid-state battery according to claim 1.

4. The content of the sulfide-based solid electrolyte is 5 to 25 parts by weight with respect to 100 parts by weight of the total of the positive electrode active material, the conductive material, and the binder. The positive electrode slurry for an all-solid-state battery according to claim 1.

5. The content of the solvent is 15 to 50 parts by weight with respect to 100 parts by weight of the total positive electrode active material, conductive material, and binder. The positive electrode slurry for an all-solid-state battery according to claim 1.

6. The weight ratio of the phosphine-based additive to the sulfide-based solid electrolyte is 0.2 to 25. The positive electrode slurry for an all-solid-state battery according to claim 1.

7. The positive electrode active material contains the compound of the following chemical formula 2: The positive electrode slurry for an all-solid-state battery according to claim 1. [Chemical formula 2] Li a Ni x Co y Mn z X c O 2-b (In the above chemical formula 2, 0.8 ≤ a ≤ 1.2, 0.8 ≤ x ≤ 1.0, 0 ≤ y ≤ 0.1, 0 ≤ z ≤ 0.1, 0 ≤ c ≤ 0.1, 0 ≤ b ≤ 0.05, and x + y + z + c = 1, where X is at least one element selected from the group consisting of Al, Ti, Mg, Zr, Mo, and Nb.)

8. The aforementioned binder includes a fluoride-based binder. The positive electrode slurry for an all-solid-state battery according to claim 1.

9. The conductive material includes at least one selected from the group consisting of natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, carbon nanotube, or a combination thereof. The positive electrode slurry for an all-solid-state battery according to claim 1.

10. The aforementioned sulfide-based solid electrolyte is Li 7-a M a PS 6-c X c It is an argyrodite-type compound containing (0 ≤ a ≤ 2, 0 ≤ c ≤ 2), The aforementioned X is F, Br, Cl, I, or a combination thereof. The aforementioned M is 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), i Lydium (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), or combinations thereof. The positive electrode slurry for an all-solid-state battery according to claim 1.

11. The process involves mixing a positive electrode active material, a conductive material, a binder, a sulfide-based solid electrolyte, a phosphine-based additive represented by the following chemical formula 1, and a solvent. A method for manufacturing a positive electrode slurry for all-solid-state batteries. 【Chemistry 2】 (In the above chemical formula 1, The aforementioned n 1 〜n 3 Each of them is independently between 0 and 5. The aforementioned R 1 ~R 3 Each of these is independently a hydrogen atom, a halogen group, a nitrile group, a nitro group, an amine group, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C1 to C10 alkoxy group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted C5 to C14 heteroaryl group.

12. The phosphine-based additives include triphenylphosphine, tris(4-trifluoromethylphenyl)phosphine, tris(4-fluorophenyl)phosphine, tris[3,5-bis(trifluoromethyl)phenyl]phosphine, and tris(4-chlorophenyl)phosphine. Tris(2,4,6-trimethylphenyl)phosphine, Tris(4-methoxyphenyl)phosphine, Tris(4-methoxyphenyl)phosphine, Tris(pentafluorophenyl)phosphine, Tris(4-methoxy-3,5-dimethylphenyl)phosphine, Tris(3,5-dimethylphenyl)phosphine It includes at least one selected from the group consisting of phosphine, tri(o-tolyl)phosphine, diphenyl(p-tolyl)phosphine, or combinations thereof. A method for producing a positive electrode slurry for an all-solid-state battery according to claim 11.

13. The aforementioned binder includes a fluoride-based binder. The aforementioned sulfide-based solid electrolyte is Li 7-a M a PS 6-c X c It is an argyrodite-type compound containing (0 ≤ a ≤ 2, 0 ≤ c ≤ 2), The aforementioned X is F, Br, Cl, I, or a combination thereof. The aforementioned M is 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), or combinations thereof. A method for producing a positive electrode slurry for an all-solid-state battery according to claim 11.

14. The content of the phosphine-based additive is 0.01 to 3 parts by weight per 100 parts by weight of the total positive electrode active material, conductive material, and binder. A method for producing a positive electrode slurry for an all-solid-state battery according to claim 11.

15. The content of the sulfide-based solid electrolyte is 5 to 25 parts by weight per 100 parts by weight of the total positive electrode active material, conductive material, and binder. A method for producing a positive electrode slurry for an all-solid-state battery according to claim 11.

16. The weight ratio of the phosphine-based additive to the sulfide-based solid electrolyte is 0.2 to 25. A method for producing a positive electrode slurry for an all-solid-state battery according to claim 11.

17. It includes a positive electrode, a negative electrode, and a solid electrolyte layer between the positive electrode and the negative electrode, The positive electrode 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 is formed using the positive electrode slurry described in claim 1. All-solid-state battery.

18. The positive electrode active material layer includes a binder modifier produced by the reaction of the sulfide-based solid electrolyte eluent with a phosphine-based additive. The all-solid-state battery according to claim 17.

19. The binder modifier comprises at least one selected from the group consisting of triphenylphosphine sulfide, phosphous sulfide, lithium sulfide, or combinations thereof. The all-solid-state battery according to claim 18.

20. The content of the binder modifying material in the positive electrode active material layer is 0.0001% by weight to 1% by weight. The all-solid-state battery according to claim 18.

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