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

Abstract

A positive electrode for an all-solid-state battery, an all-solid-state battery including the same, and a method of manufacturing a positive electrode for an all-solid-state battery are disclosed. The positive electrode includes a positive electrode current collector, a positive electrode active material layer on the positive electrode current collector, and a porous membrane in the positive electrode active material layer. The positive electrode active material layer includes positive electrode active material particles and solid electrolyte particles. The positive electrode active material layer has a first portion and a second portion that are different across the porous membrane. The first portion is between the positive electrode current collector and the porous membrane. An average particle diameter of the solid electrolyte particles in the first portion is different from an average particle diameter of the solid electrolyte particles in the second portion.

Description

[0001] This application claims priority to Korean Patent Application No. 10-2024-0110674, filed on August 19, 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. Background Technology

[0003] With the increasing use of battery-powered electronic devices (such as mobile phones, laptops, and electric vehicles), the demand for rechargeable batteries with high energy density and high capacity is increasing. Therefore, improving the performance of rechargeable lithium batteries would be beneficial.

[0004] All-solid-state batteries are batteries that replace the liquid electrolyte with a solid electrolyte. Because all-solid-state batteries do not use flammable organic dispersion media, the possibility of fire or explosion is significantly reduced, even in the event of a short circuit. Therefore, compared to lithium-ion batteries that use liquid electrolytes, all-solid-state batteries offer a significantly increased level of safety. Summary of the Invention

[0005] Example embodiments of this disclosure include a positive electrode having high capacity in a limited volume, desired or improved ionic conductivity, and high current density for all-solid-state batteries.

[0006] Exemplary embodiments of this disclosure include all-solid-state batteries with high capacity, uniform thickness and mass, increased cycle life, and high efficiency.

[0007] Example embodiments of this disclosure include a method for manufacturing a positive electrode for an all-solid-state battery, a method capable of producing and suitable for mass production.

[0008] According to an example embodiment of this disclosure, the positive electrode for an all-solid-state battery may include a positive electrode current collector, a positive electrode active material layer on the positive electrode current collector, and a porous membrane in the positive electrode active material layer. The positive electrode active material layer may include positive electrode active material particles and solid electrolyte particles. The positive electrode active material layer may have a first portion and a second portion that are different across the porous membrane. The first portion may be located between the positive electrode current collector and the porous membrane. The average particle size of the solid electrolyte particles in the first portion may be different from the average particle size of the solid electrolyte particles in the second portion.

[0009] According to an example embodiment of this disclosure, an all-solid-state battery may include the positive electrode discussed above, a negative electrode opposite to the positive electrode, and a solid electrolyte layer between the positive electrode and the negative electrode.

[0010] According to an example embodiment of this disclosure, a method for manufacturing a positive electrode for an all-solid-state battery may include the following steps: preparing a first positive electrode slurry comprising first solid electrolyte particles; preparing a second positive electrode slurry comprising second solid electrolyte particles; coating a positive electrode current collector with the first positive electrode slurry to form a first preliminary active material layer; placing a composite layer comprising a porous membrane on the first preliminary active material layer; and pressing the stacked (e.g., sequentially stacked) positive electrode current collector, the first preliminary active material layer, and the composite layer together. The step of forming the composite layer may include providing a preliminary porous membrane and coating the preliminary porous membrane with the second positive electrode slurry to form the composite layer. The average particle size of the first solid electrolyte particles may be different from the average particle size of the second solid electrolyte particles. Attached Figure Description

[0011] Figure 1 A cross-sectional view of an all-solid-state battery according to an example embodiment of the present disclosure is shown.

[0012] Figure 2 A cross-sectional view of an all-solid-state battery according to an example embodiment of the present disclosure is shown.

[0013] Figure 3 A plan view illustrating an all-solid-state battery according to an example embodiment of the present disclosure is shown.

[0014] Figure 4 A cross-sectional view of an all-solid-state battery according to an example embodiment of the present disclosure is shown.

[0015] Figure 5 A cross-sectional view of an all-solid-state battery according to an example embodiment of the present disclosure is shown.

[0016] Figure 6 A cross-sectional view of an all-solid-state battery including a pad structure, illustrating an example embodiment of the present disclosure, is shown.

[0017] Figure 7 A cross-sectional view of an all-solid-state battery according to an example embodiment of the present disclosure is shown.

[0018] Figure 8 The illustration shows an example embodiment of the present disclosure for use with Figure 7 A detailed cross-sectional view of the positive electrode of an all-solid-state battery.

[0019] Figure 9 and Figure 10 A cross-sectional view of a positive electrode for an all-solid-state battery is shown, illustrating the location of a porous membrane disposed in the positive electrode active material according to an example embodiment.

[0020] Figure 11A cross-sectional view is shown illustrating a positive electrode for an all-solid-state battery according to an example embodiment of the present disclosure.

[0021] Figure 12A and Figure 12B A cross-sectional view is shown illustrating a method for forming a composite layer according to an example embodiment of the present disclosure.

[0022] Figures 13 to 15 A cross-sectional view is shown illustrating a method for manufacturing a positive electrode for an all-solid-state battery according to an exemplary embodiment of the present disclosure.

[0023] Figure 16 The diagram shows Nyquist plots illustrating impedance measurement results based on the positive electrode according to some example embodiments and comparative examples.

[0024] Figure 17 This is a flowchart illustrating a method for manufacturing a positive electrode for an all-solid-state battery according to various example embodiments. Detailed Implementation

[0025] 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.

[0026] In this disclosure, it should be understood that when an element is referred to as being "on" another element, the element may be "directly on" said other element, or an intervening element may be present between them. In the accompanying drawings, the thickness of some components may be exaggerated for the purpose of effectively explaining the technical content. Throughout the specification, the same reference numerals refer to the same elements.

[0027] Some exemplary embodiments detailed in this specification are discussed with reference to cross-sectional views and / or plan views, which serve as ideal example diagrams of this disclosure. In the drawings, the thickness of layers and regions may be exaggerated for the purpose of effectively explaining the technical content. Therefore, the regions shown in the drawings have general properties, and the shapes of the regions shown in the drawings are used to disclose specific shapes, but are not limited to the scope of this disclosure. It should be understood that although the terms "first," "second," "third," etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. Some exemplary embodiments explained and illustrated herein include complementary embodiments thereof.

[0028] The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to limit this disclosure. As used herein, the singular form is intended to include the plural form as well. The term "comprising / including" and / or variations thereof as used in the specification does not exclude the presence or addition of one or more other components.

[0029] In this disclosure, the term "combination thereof" may refer to mixtures, stacks, complexes, copolymers, alloys, blends, or reaction products.

[0030] Unless otherwise specifically defined in this disclosure, particle size can be the average particle size. Additionally, particle size refers to the average particle size (D) that constitutes approximately 50% of the cumulative volume in the particle size distribution. 50 Average particle size (D) 50 The particle size can be measured using methods widely known to those skilled in the art (e.g., by a particle size analyzer, transmission electron microscopy (TEM) images, or scanning electron microscopy (SEM) images). Alternatively, data analysis can be performed using a dynamic light scattering measurement device to calculate the number of particles in each particle size range, from which the average particle size (D) can then be calculated. 50 The average particle size (D) can be measured using laser scattering, unlike other methods. 50 In the laser scattering method, target particles are distributed in a dispersion solvent and introduced into a laser scattering particle measuring device (e.g., the MT3000, commercially available from Microtrac). The particles are irradiated with ultrasound at 28 kHz at a power of 60 W. The average particle size (D) is then calculated in the measuring device using a 50% standard of particle size distribution. 50 ).

[0031] When the terms “about” or “substantially” are used in conjunction with numerical values ​​in this specification, it means that the relevant numerical value includes a tolerance of ±10% around the stated value. When a range is specified, the range includes all values ​​within that range (such as increments of 0.1%).

[0032] Figure 1 This is a cross-sectional view showing an all-solid-state battery 10 according to an exemplary embodiment of the present disclosure.

[0033] Reference Figure 1 The all-solid-state battery 10 may include a positive electrode 100, a negative electrode 200 opposite to the positive electrode 100, and a solid electrolyte layer 300 between the positive electrode 100 and the negative electrode 200. However, this disclosure is not limited thereto, and the all-solid-state battery 10 may also include additional functional layers (such as an adhesion enhancement layer, for example) between the positive electrode 100 and the solid electrolyte layer 300 or between the negative electrode 200 and the solid electrolyte layer 300.

[0034] The positive electrode 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 a positive electrode active material, a solid electrolyte, a conductive material, and a binder.

[0035] 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 can 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.

[0036] and Figure 1 As shown in the example embodiments 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.

[0037] The positive electrode active material may include materials capable of reversibly inserting and deintercalating 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.

[0038] 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 at least 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, and "J" can be or include at least one of V, Cr, Mn, Co, Ni, Cu, and combinations thereof.

[0039] 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, and 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 class of crystal structures, and for example, has a structure in which face-centered cubic lattices (FCCs) each formed by cations and anions are arranged with a shift of 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 all-solid-state battery 10 can improve energy density and thermal stability.

[0040] The compound included in the positive electrode active material may be covered by a coating layer (not shown). The positive electrode active material may be used as a mixture of the compound and the compound to which the coating layer is added. The coating layer added to the surface of the positive electrode active material may include at least one of oxides, hydroxides, hydroxyoxides, oxycarbonates, and bicarbonates of the coating elements discussed below. The compound forming the coating layer may be or may include amorphous or crystalline. The coating elements included in the coating layer 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 layer may include, for example, Li₂O-ZrO₂ (LZO). The method for forming the coating layer may be any method that does not adversely affect the physical properties of the positive electrode active material. The method for forming the coating layer may include, for example, spraying or dipping.

[0041] When the positive electrode active material includes nickel (Ni) as a ternary lithium transition metal oxide (such as NCA or NCM), the capacity density of the all-solid-state battery 10 can be increased to reduce metal leaching from the positive electrode active material during the charging state. Therefore, the all-solid-state battery 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 all-solid-state battery 10 due to charging and discharging. For example, an all-solid-state battery 10 with high cycle characteristics may degrade less due to charging and discharging, while an all-solid-state battery 10 with low cycle characteristics may degrade more due to charging and discharging.

[0042] The positive electrode active material can have, for example, a substantially spherical or substantially elliptical particle shape. There are no limitations on the particle size and amount of the positive electrode active material.

[0043] 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 both 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 both 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).

[0044] 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 At least one of the following (where 0 ≤ x ≤ 2). For example, the sulfide-based solid electrolyte can be or includes a sulfhydryl germanite-type compound, which includes at least one of Li6PS5Cl, Li6PS5Br, and Li6PS5I. The sulfhydryl germanite-type solid electrolyte can have a density in the range of about 1.5 g / cc to about 2.0 g / cc. Because the sulfhydryl germanite-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 the formation of lithium dendrites can be hindered or prevented. The solid electrolyte can have an elastic modulus in the range of, for example, about 15 GPa to about 35 GPa.

[0045] The solid electrolyte included in the positive electrode active material layer 120 can have a medium average particle size (D) smaller than the average particle size of the solid electrolyte included in the solid electrolyte layer 300. 50 For example, the average particle size (D) of the solid electrolyte in the positive electrode active material layer 120. 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 approximately equal to or less than approximately 90%, 80%, 70%, 60%, 50%, 40%, 30%, or 20%. 50 The median particle size can be measured using a laser particle size distribution analyzer.

[0046] The positive electrode active material layer 120 may include a conductive material. The conductive material can be conductive without causing chemical changes in the all-solid-state battery 10 to increase the conductivity of 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.

[0047] The positive electrode active material layer 120 may further include an adhesive. The adhesive may include materials that adhere the positive electrode active material, solid electrolyte, and conductive material included in the positive electrode active material layer 120 together and improve 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, vinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, and polymethyl methacrylate.

[0048] In the positive electrode active material layer 120, the amount of positive electrode active material included can range from about 85 parts by weight to about 92 parts by weight relative to the total of 100 parts by weight of positive electrode active material, solid electrolyte, conductive material and binder. The amount of binder included in the positive electrode active material layer 120 can range from about 0.5 parts by weight to about 1.5 parts by weight.

[0049] In the positive electrode active material layer 120, the amount of conductive material present relative to 100 parts by weight of solid electrolyte can range from about 1 part by weight to about 50 parts by weight. When the amount of conductive material present relative to 100 parts by weight of solid electrolyte is less than about 1 part by weight, the electrical conductivity of the positive electrode active material layer 120 may decrease. When the amount of conductive material present relative to 100 parts by weight of solid electrolyte is greater than about 50 parts by weight, the proportion of conductive material increases significantly, resulting in incomplete formation of the coating layer covering the surface of the solid electrolyte.

[0050] 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 ion conductor).

[0051] The solid electrolyte layer 300 may be located between the positive electrode 100 and the negative electrode 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.

[0052] The solid electrolyte layer 300 may also include a binder. The binder included in the solid electrolyte layer 300 may include at least one of, for example, 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 layer 220 discussed below.

[0053] The negative electrode 200 may include a negative electrode current collector 210 and a negative electrode coating layer 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 layer 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 (e.g., a material that does not form alloys or compounds with lithium). For example, the negative electrode current collector 210 may include 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 (e.g., from about 5 μm to about 15 μm or from about 7 μm to about 10 μm).

[0054] The negative electrode current collector 210 may be formed or comprise one of the metals discussed above, an alloy of two or more of the metals discussed above, or a coating material. The negative electrode current collector 210 may have, for example, the shape of a plate or foil. In the example embodiment, the negative electrode current collector 210 may be omitted.

[0055] When the all-solid-state battery 10 is charged, the negative electrode coating layer 220 can induce lithium metal to grow between the negative electrode coating layer 220 and the negative electrode current collector 210. The negative electrode coating layer 220 can be configured as a protective layer for lithium metal and can simultaneously reduce or suppress the precipitation and growth of lithium dendrites.

[0056] The negative electrode coating 220 may comprise a metal and carbon. For example, the negative electrode coating 220 may comprise 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 comprise at least one carbon-based material (such as or including at least one of carbon black, acetylene black, furnace black, Ketjen black, and graphene). In an example embodiment, the negative electrode coating 220 may comprise a mixture of carbon black and silver (Ag).

[0057] In addition to metals and carbon, the negative electrode coating layer 220 may also include additives. The negative electrode coating layer 220 may include at least one additive (such as or including at least one of binders, fillers, coating agents, dispersants and ion conductors).

[0058] The negative electrode coating layer 220 can have a thickness smaller than that of the positive electrode active material layer 120. For example, the negative electrode coating layer 220 can have a thickness 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 layer 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 layer 220 has a substantially small thickness, lithium dendrites formed between the negative electrode coating layer 220 and the negative electrode current collector 210 may cause the negative electrode coating layer 220 to collapse, thereby reducing the cycle characteristics of the all-solid-state battery 10. When the negative electrode coating layer 220 has a substantially large thickness, the all-solid-state battery 10 may have a reduced energy density and increased internal resistance caused by the negative electrode coating layer 220, thereby reducing the cycle characteristics of the all-solid-state battery 10.

[0059] Although not shown, a carbon layer may also be included to increase the adhesion between the negative electrode coating layer 220 and the solid electrolyte layer 300.

[0060] Figure 2 A cross-sectional view is shown, illustrating an all-solid-state battery 10 according to an example embodiment of the present disclosure.

[0061] Reference Figure 2 The solid electrolyte layer 300 may include a positive electrode solid electrolyte layer 310 and a negative electrode solid electrolyte layer 320. The positive electrode solid electrolyte layer 310 may be adjacent to the positive electrode 100, and the negative electrode solid electrolyte layer 320 may be adjacent to the negative electrode 200. Each of the positive electrode solid electrolyte layer 310 and the negative electrode solid electrolyte layer 320 may include the solid electrolyte discussed above.

[0062] The positive electrode solid electrolyte layer 310 and the negative electrode solid electrolyte layer 320 may have different thicknesses. The positive electrode solid electrolyte layer 310 may have a first thickness TK1, and the negative electrode 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 in the range of about 10 times to about 100 times the second thickness TK2.

[0063] Figure 3 A plan view of an all-solid-state battery 10 according to an example embodiment of the present disclosure is shown. Figure 4 It shows along Figure 3 A cross-sectional view taken along line A-A'. In the example embodiments below, the reference above is omitted. Figure 1 and Figure 2 The technical features discussed are redundant and described in detail, with their differences also discussed in detail.

[0064] Reference Figure 3 and Figure 4 The areas of the positive electrode 100 and the negative electrode 200 can be different from each other. For example, the area of ​​the negative electrode 200 can be larger than the area of ​​the positive electrode 100. The positive electrode 100 can be substantially completely superimposed on the negative electrode 200.

[0065] In an exemplary embodiment of this disclosure, the positive electrode solid electrolyte layer 310 may have an area substantially the same as that of the positive electrode 100. The negative electrode solid electrolyte layer 320 may have an area substantially the same as that of the negative electrode 200.

[0066] The positive electrode solid electrolyte layer 310 may have a first width WI1 in the first direction D1. The negative electrode 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 positive electrode solid electrolyte layer 310 may have a third width WI3 in the second direction D2. The negative electrode 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.

[0067] The all-solid-state battery 10 according to this example embodiment can be manufactured by forming a first stack of a positive electrode 100 and a positive electrode solid electrolyte layer 310, forming a second stack of a negative electrode 200 and a negative electrode solid electrolyte layer 320, and then laminating the first stack and the second stack together.

[0068] Figure 5 It shows along Figure 3 A cross-sectional view taken along line A-A', which shows an all-solid-state battery according to an exemplary embodiment of the present disclosure.

[0069] Reference Figure 5 The negative electrode 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 negative electrode coating layer 220. When the all-solid-state battery 10 is charged, the lithium metal layer 400 may have an increased thickness. The negative electrode coating layer 220 may be configured as a protective layer for the lithium metal layer 400, and may simultaneously or concurrently reduce or suppress the growth of lithium dendrites from the lithium metal layer 400.

[0070] The lithium metal layer 400 may be or include a thin metal layer comprising lithium or a lithium alloy. The lithium alloy may be or include at least one of, for example, 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, and any suitable lithium alloy may be used. The lithium metal layer 400 may include lithium or one of the aforementioned alloys. Optionally, the lithium metal layer 400 may include various types of alloys.

[0071] 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 greater than the first width WI1. The fifth width WI5 may be the same as or less than the second width WI2. For example, the fifth width WI5 may be greater than the first width WI1 and less than the second width WI2.

[0072] Figure 6 A cross-sectional view of an all-solid-state battery according to an example embodiment of the present disclosure is shown.

[0073] Reference Figure 6 The all-solid-state battery 10 may include a pad structure 500. The area difference between the first and second stacks discussed above creates a step difference on the lateral surface of the all-solid-state battery 10, and the pad structure 500 can substantially fill this step difference. The pad structure 500 may surround the lateral surfaces of the first stack of the all-solid-state battery 10 in a first direction D1 and a second direction D2. For example, the thickness of the pad structure 500 may be substantially the same as the thickness of the first stack. Therefore, even when first and second stacks with different areas are stacked and pressed together, the all-solid-state battery 10 can be substantially protected or substantially prevented from damage caused by the step difference on the lateral surface. The phrase "substantially the same thickness" can refer to a thickness sufficient to reduce or prevent damage caused by the step difference on the lateral surface of the all-solid-state battery 10, even when first and second stacks with different areas are stacked and pressed together.

[0074] The following description focuses on all-solid-state batteries according to some exemplary embodiments of the present disclosure and the positive electrode included in the all-solid-state battery. In the exemplary embodiments below, references to the above are omitted. Figures 1 to 6 The discussion provides a detailed description of the redundant technical features and explains their differences in detail.

[0075] Figure 7 A cross-sectional view of an all-solid-state battery according to an example embodiment of the present disclosure is shown.

[0076] Reference Figure 7The all-solid-state battery 10 may include a positive electrode 100, a solid electrolyte layer 300 on the positive electrode 100, and a negative electrode 200 on the solid electrolyte layer 300. The positive electrode 100 may include a positive electrode current collector 110, a positive electrode active material layer 120 on the positive electrode current collector 110, and a porous membrane PW in the positive electrode active material layer 120.

[0077] Still refer to Figure 7 The positive electrode active material layer 120 may include a first portion RG1 and a second portion RG2. The first portion RG1 and the second portion RG2 may be different along the porous membrane PW. The first portion RG1 may refer to the region between the positive electrode current collector 110 and the porous membrane PW. The second portion RG2 may refer to the region across the porous membrane PW that is spaced relative to the first portion RG1. For example, the second portion RG2 may refer to the region between the solid electrolyte layer 300 and the porous membrane PW.

[0078] The positive electrode active material layer 120 may include positive electrode active material particles (PPT) and solid electrolyte particles (SPT). The solid electrolyte layer 300 may include solid electrolyte particles (SPT). For example, the positive electrode active material layer 120 may include first solid electrolyte particles (SPT1) and second solid electrolyte particles (SPT2). The solid electrolyte layer 300 may include third solid electrolyte particles (SPT3). For example, a first portion RG1 may include first solid electrolyte particles (SPT1) and second solid electrolyte particles (SPT2). A second portion RG2 may include second solid electrolyte particles (SPT2).

[0079] Solid electrolyte particles (SPT) may include references Figure 1 Solid electrolytes are discussed. For example, solid electrolyte particles (SPTs) can include sulfide-based solid electrolytes.

[0080] The first solid electrolyte particle SPT1 can be disposed on the portion of the first part RG1 adjacent to the positive electrode current collector 110, and the second solid electrolyte particle SPT2 can be disposed on the portion of the first part RG1 adjacent to the porous membrane PW.

[0081] In the example embodiment, the average particle size (D) of the solid electrolyte particles SPT in the solid electrolyte layer 300 is... 50 The particle size of the solid electrolyte particles (SPT) in the positive electrode active material layer 120 can be larger than the average particle size of the solid electrolyte particles (SPT). For example, the average particle size of the first solid electrolyte particle (SPT1) (D...) 50 The average particle size (D) of the second solid electrolyte particle SPT2 can be smaller than that of the second solid electrolyte particle SPT2. 50 It can be smaller than the average particle size of the third solid electrolyte particle SPT3.

[0082] In the example embodiment, the average particle size (D) of the positive electrode active material particles PPT is... 50 The range of ) can be from about 2 μm to about 20 μm, for example, from about 2 μm to about 10 μm, from about 5 μm to about 15 μm or from about 10 μm to about 20 μm.

[0083] In the example embodiment, the average particle size (D) of the first solid electrolyte particle SPT1 is... 50 The size can be equal to or less than about 1.5 μm, for example, about 0.2 μm to about 1.0 μm or about 0.5 μm to about 1.5 μm.

[0084] In the example embodiment, the average particle size (D) of the second solid electrolyte particle SPT2 is... 50 The range of ) can be from about 1.5 μm to about 2.5 μm, for example, from about 1.5 μm to about 2.0 μm or from about 2.0 μm to about 2.5 μm.

[0085] In the example embodiment, the average particle size (D) of the third solid electrolyte particle SPT3 is... 50 The range of ) can be from about 2.5 μm to about 5 μm, for example, from about 3 μm to about 5 μm.

[0086] Average particle size (D) 50 () can refer to the diameter of particles that have a cumulative volume of 50 vol% in the particle size distribution.

[0087] Because the solid electrolyte particles (SPTs) in the positive electrode active material layer 120 have a relatively small average particle size, they can fill the gaps between the positive electrode active material particles (PPTs), thereby improving ionic conductivity. Conversely, the solid electrolyte particles (SPTs) in the solid electrolyte layer 300 can have a relatively large particle size, thus establishing robust ion migration pathways.

[0088] The average particle size of the solid electrolyte particles (SPT) can vary in different portions of the positive electrode active material layer 120. In an example embodiment, in the positive electrode active material layer 120, the average particle size (D) of the solid electrolyte particles (SPT) in the portion adjacent to the positive electrode current collector 110 is... 50 It can be smaller than the average particle size of the solid electrolyte particles SPT in the portion adjacent to the solid electrolyte layer 300.

[0089] In an example embodiment, the average particle size (D) of the solid electrolyte particles SPT included in the first portion RG1 of the positive electrode active material layer 120 is... 50The size of the solid electrolyte particles (SPT) can be smaller than the average particle size of the solid electrolyte particles (SPT) included in the second part RG2 of the positive electrode active material layer 120. As the size of the solid electrolyte particles (SPT) gradually increases in the direction from the positive electrode current collector 110 toward the solid electrolyte layer 300, lithium ions can be transferred efficiently, thereby improving ionic conductivity.

[0090] The positive electrode active material layer 120 may further include a binder and / or a conductive material. Each of the binder and conductive material may be referenced above. Figure 1 The adhesives and conductive materials discussed are the same.

[0091] A 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, and the porous membrane PW can accommodate an amount of active material sufficient to act as a self-standing membrane for the positive electrode.

[0092] Porous membranes (PWs) can have small thicknesses. The thickness of porous membranes (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 ranges, the loading level of the positive electrode 100 can be improved without substantially interrupting the movement of lithium ions in the positive electrode 100.

[0093] Porous membranes (PW) can have a density of approximately 2 g / m³. 2 Approximately 4g / m 2 The weight range is within a certain range. For example, the weight range of porous membrane PW can be from approximately 2.5 g / m³. 2 Approximately 3.5 g / m 2 .

[0094] 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 range from about 0.1 N / mm to about 0.13 N / mm.

[0095] The permeability per thickness of a porous membrane (PW) can range from about 0.1 sec / 100 ml to about 1 sec / 100 ml. For example, the permeability per thickness of a porous membrane (PW) can range from about 0.1 sec / 100 ml to about 0.5 sec / 100 ml.

[0096] The porous membrane PW may include at least one of polyester, polyolefin, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyethersulfone, polyphenylene ether, and polyphenylene sulfide. For example, polyester may include at least one of polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate.

[0097] For example, a porous membrane PW can be or includes a porous nonwoven fabric.

[0098] Figure 8 It shows the use of Figure 7 A detailed cross-sectional view of the positive electrode of an all-solid-state battery. In the example embodiments below, details consistent with those referenced above are omitted. Figure 7 The technical features discussed are redundant and described in detail, with their differences also discussed in detail.

[0099] Reference Figure 8 The positive electrode active material layer 120 can be divided into multiple sub-layers according to the structure of the porous membrane PW and the positive electrode current collector 110. For example, the positive electrode active material layer 120 may include a first sub-layer P1 disposed on the positive electrode current collector 110, a second sub-layer P2 disposed between the first sub-layer P1 and the porous membrane PW, and a third sub-layer P3 disposed on the porous membrane PW. The third sub-layer P3 may be spaced apart from the second sub-layer P2 across the porous membrane PW.

[0100] The first sublayer P1 and the second sublayer P2 can be positioned above for reference. Figure 7 In the first part of the discussion, RG1, the third sublayer P3 can be located above the reference. Figure 7 The second part of the discussion is RG2.

[0101] In an example embodiment, the first sublayer P1 may include positive electrode active material particles PPT and first solid electrolyte particles SPT1. The second sublayer P2 may include positive electrode active material particles PPT and second solid electrolyte particles SPT2. The third sublayer P3 may include positive electrode active material particles PPT and second solid electrolyte particles SPT2.

[0102] Figure 9 and Figure 10 A cross-sectional view of a positive electrode for an all-solid-state battery according to an example embodiment is shown, illustrating the location of a porous membrane disposed in the positive electrode active material.

[0103] Reference Figure 9 and Figure 10The second sublayer P2 and the third sublayer P3 may have different thicknesses than each other. In an example embodiment, the ratio of the thickness c of the second sublayer P2 in the third direction D3 to the thickness d of the third sublayer P3 in the third direction D3 can range from about 2 to about 10, from about 3 to about 10, or from about 4 to about 7. For example, the thickness c of the second sublayer P2 can range from about 5 μm to about 20 μm, from about 5 μm to about 15 μm, or from about 7 μm to about 10 μm. The thickness d of the third sublayer P3 can range from about 40 μm to about 80 μm, from about 40 μm to about 70 μm, or from about 50 μm to about 70 μm.

[0104] The first sublayer P1 and the second sublayer P2 can have a single, uniform shape. An interface may not be separately provided between the first sublayer P1 and the second sublayer P2, and the active material included in the first sublayer P1 and the active material included in the second sublayer P2 can be mixed with each other to provide a single mixed active material layer with a single, uniform shape. Although not shown in detail, the active material included in the second sublayer P2 can be mixed with the active material permeating into the pores of the porous membrane PW, thereby providing a mixed active material layer with a single, uniform shape. The active material included in the third sublayer P3 can be mixed with the active material permeating into the pores of the porous membrane PW, thereby providing a mixed active material layer with a single, uniform shape. For example, in the positive electrode active material layer 120, the active material included in the first sublayer P1, the active material included in the second sublayer P2, the active material included in the third sublayer P3, and the active material permeating into the pores of the porous membrane PW can be mixed with each other to provide a single mixed active material layer.

[0105] Still refer to Figure 9 and Figure 10 The positive electrode active material layer 120 may have a first thickness a, and the porous membrane PW may be located in the positive electrode active material layer 120 at a first distance b from the positive electrode current collector 110. The first thickness a and the first distance b may satisfy the relationship of Equation 1 below. The first thickness a and the first distance b may each have a unit of micrometer (μm).

[0106] Formula 1: 0.5 ​For example, the first distance b between the porous membrane PW and the positive electrode current collector 110 can be in the range of about 50% to about 80% of the first thickness a or the total thickness of the positive electrode active material layer 120. In an example embodiment, the first distance b between the porous membrane PW and the positive electrode current collector 110 can be in the range of about 55% to about 75% or about 55% to about 70% of the first thickness a of the positive electrode active material layer 120. When the first distance b between the porous membrane PW and the positive electrode current collector 110 and the first thickness a of the positive electrode active material layer 120 satisfy the relationship of Equation 1 above, the all-solid-state battery can achieve high current density while exhibiting desired or improved cycle life characteristics.

[0107] In an example embodiment, the first thickness 'a' of the positive electrode active material layer 120 can range from about 100 μm to about 200 μm, from about 120 μm to about 180 μm, or from about 140 μm to about 150 μm. In an example embodiment, the first distance 'b' between the porous membrane PW and the positive electrode current collector 110 can range from about 50 μm to about 160 μm, from about 70 μm to about 100 μm, or from about 80 μm to about 90 μm.

[0108] According to some exemplary embodiments of this disclosure, the positive electrode 100 for an all-solid-state battery may include a porous membrane PW located in a positive electrode active material layer 120, and the positive electrode active material layer 120 may include multiple sublayers 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 by taking into account the diffusion coefficient of lithium ions, conduction between particles, and the path to the current collector. In the positive electrode 100 for an all-solid-state battery according to the exemplary embodiments, based on the positive electrode active material layer 120 located on one side of the positive electrode current collector 110, the positive electrode active material particles may have a loading level 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 loading level. When the positive electrode active material layer 120 is coated on the opposite side of the positive electrode current collector 110, the positive electrode active material can have a loading level equal to or greater than about 70 mg / cm³. 2 Equal to or greater than approximately 80 mg / cm³ 2 or equal to or greater than approximately 90 mg / cm³ 2 The load level.

[0109] Figure 11 A cross-sectional view illustrating a positive electrode for an all-solid-state battery according to an embodiment of the present disclosure is shown. In the following embodiments, details referenced above are omitted. Figures 7 to 10The discussion provides a detailed description of the redundant technical features and explains their differences in detail.

[0110] Reference Figure 11 The positive electrode 100 for an all-solid-state battery according to an example embodiment may include a positive electrode current collector 110, a positive electrode active material layer 120 on the positive electrode current collector 110, and a porous membrane PW disposed in the positive electrode active material layer 120. The porous membrane PW may include a plurality of sub-porous membranes.

[0111] For example, the positive electrode 100 for an all-solid-state battery according to an example embodiment can be configured such that the positive electrode active material layer 120 can have a first subporous membrane PW-a and a second subporous membrane PW-b disposed therein. The second subporous membrane PW-b can be spaced apart from the positive electrode current collector 110 across the first subporous membrane PW-a.

[0112] Each or at least one of the plurality of subporous membranes PW-a and PW-b can be disposed in the positive electrode active material layer 120, and the positive electrode active material particles included in the positive electrode active material layer 120 can permeate into each of the subporous membranes PW-a and PW-b.

[0113] The first sublayer P1 and the second sublayer P2 can have a single, uniform shape. An interface may not be separately provided between the first sublayer P1 and the second sublayer P2, and the active substances included in the first sublayer P1 and the second sublayer P2 can be mixed with each other to provide a single layer of mixed active substances with a single, uniform shape. The third sublayer P3 and the fourth sublayer P4 can also have a single, uniform shape. An interface may not be separately provided between the third sublayer P3 and the fourth sublayer P4, and the active substances included in the third sublayer P3 and the fourth sublayer P4 can be mixed with each other to provide a single layer of mixed active substances with a single, uniform shape.

[0114] Although not shown in detail, the active materials included in the second sublayer P2 and the third sublayer P3 can be mixed with the active materials permeating into the pores of the first subporous membrane PW-a, thereby providing a single, uniformly shaped layer of mixed active materials. Similarly, the active materials included in the fourth sublayer P4 and the fifth sublayer P5 can be mixed with the active materials permeating into the pores of the second subporous membrane PW-b, thereby providing a single, uniformly shaped layer of mixed active materials. For example, in the positive electrode active material layer 120, the active materials included in each of the first to fifth sublayers P1 to P5 and the active materials permeating into the pores of each of the first and second subporous membranes PW-a and PW-b can be mixed together to provide a single, uniformly shaped layer of mixed active materials.

[0115] In an example embodiment, each or at least one of the first sublayers P1 to the fifth sublayer P5 may include positive electrode active material particles PPT and solid electrolyte particles SPT. The average particle size (D) of the solid electrolyte particles SPT is... 50 The particle size (D) of the solid electrolyte particles SPT in the first sublayer P1 can increase in the direction from the first sublayer P1 to the fifth sublayer P5. For example, the first sublayer P1 may include a first solid electrolyte particle SPT1. Each or at least one of the second sublayer P2 and the third sublayer P3 may include a second solid electrolyte particle SPT2. Each or at least one of the fourth sublayer P4 and the fifth sublayer P5 may include a second solid electrolyte particle SPT2 and a third solid electrolyte particle SPT3. The average particle size (D) of the solid electrolyte particles SPT in the first sublayer P1... 50 The particle size of the solid electrolyte particles (SPT) in the third sublayer P3 can be smaller than the average particle size of the SPT particles in the third sublayer P3. 50 It can be smaller than the average particle size of the solid electrolyte particles SPT in the fifth sublayer P5.

[0116] The following describes a method for manufacturing a positive electrode for an all-solid-state battery according to an example embodiment.

[0117] A method for manufacturing a positive electrode for an all-solid-state battery may include the following steps: preparing a first positive electrode slurry comprising first solid electrolyte particles; coating the first positive electrode slurry onto a positive electrode current collector to form a first preliminary active material layer; placing a composite layer comprising a porous membrane on the first preliminary active material layer; and pressing the positive electrode current collector, the first preliminary active material layer, and the composite layer together (e.g., sequentially stacked).

[0118] The steps of a method for manufacturing a positive electrode for an all-solid-state battery may further include forming a composite layer. The step of forming the composite layer may include preparing a second positive electrode slurry comprising second solid electrolyte particles and coating the second positive electrode slurry onto a preliminary porous membrane to form the composite layer.

[0119] The step of forming a first preliminary active material layer on the positive electrode current collector may include coating the positive electrode current collector with a first positive electrode slurry and drying it.

[0120] The first positive electrode slurry may include a positive electrode active material, first solid electrolyte particles, a conductive material, and a binder. The description of the positive electrode active material, conductive material, and binder included in the first positive electrode slurry can be found in the above reference. Figure 1 The description discussed is the same. The first solid electrolyte particle can be compared with the above reference. Figure 7 and Figure 8 The first solid electrolyte particles discussed are the same.

[0121] In an example embodiment, the first positive electrode paste may include at least one of styrene-butadiene rubber, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polyvinyl alcohol, vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, and polymethyl methacrylate as a binder.

[0122] Figure 12A and Figure 12B A cross-sectional view is shown illustrating a method for forming a composite layer according to an example embodiment of the present disclosure.

[0123] Reference Figure 12A and Figure 12B A preliminary porous membrane (PWA) can be formed on a release membrane RF. The 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 the first direction D1. The preliminary porous membrane PWA can be stacked on the release membrane RF along a third direction D3. The third direction D3 may intersect 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 nm to about 500 nm. 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 about 8 μm to about 12 μm. In an example embodiment, the preliminary porous membrane PWA may be or include a porous nonwoven fabric.

[0124] like Figure 12A As shown, 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 on a third direction D3 that is not laminated with the adhesive BD, and the first region A1 may be located on an opposite side or end side of the preliminary porous membrane (PWA). The second region A2 may be a region other than the first region A1.

[0125] The adhesive BD can be formed by coating and then curing a first region A1 of a preliminary porous membrane PWA. The adhesive BD may include at least one of a thermosetting resin and a UV-curable resin.

[0126] After the binder BD is formed, a second positive electrode slurry AM can be provided or coated on the preliminary porous membrane PWA. The second positive electrode slurry AM can be disposed on the second region A2 of the preliminary porous membrane PWA.

[0127] The second positive electrode slurry AM may include at least one of a positive electrode active material, a second solid electrolyte particles, a conductive material, and a binder. The description of the positive electrode active material, conductive material, and binder included in the second positive electrode slurry AM can be found in the above reference. Figure 2 The description in the discussion is the same. The second solid electrolyte particle can be compared with the reference. Figure 7 and Figure 8 The second solid electrolyte particles discussed are essentially the same. The average particle size (D) of the second solid electrolyte particles 50 The particle size can be larger than the average particle size of the first solid electrolyte particles.

[0128] In an example embodiment, the second positive electrode slurry AM may include at least one of styrene-butadiene rubber, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polyvinyl alcohol, vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, and polymethyl methacrylate as a binder.

[0129] After the second positive electrode paste AM is coated onto the preliminary porous membrane PWA, the second positive electrode paste AM can be cured.

[0130] A second positive electrode paste AM disposed on a 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 AM is provided or deposited on the second region A2, the second positive electrode paste AM can permeate into the pores of the preliminary porous membrane PWA. The second positive electrode paste AM can permeate into the pores of the preliminary porous membrane PWA to form a porous membrane PW, the pores of which are filled with the second positive electrode paste AM.

[0131] After coating the second positive electrode paste AM and allowing it to penetrate 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 AM 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 AM can not penetrate the porous membrane PW to form a third preliminary active material layer PA3 on the porous membrane PW.

[0132] The second preliminary active material layer PA2, which moves through the pores of the porous membrane PW, can have a smaller thickness than the third preliminary active material layer PA3, which does not pass through the porous membrane PW. In example embodiments, the thickness ratio of the third preliminary active material layer PA3 to the second preliminary active material layer PA2 can range from about 2 to about 10, from about 3 to about 10, or from about 4 to about 7.

[0133] Although not shown in detail, the positive electrode active material included in each of the second preliminary active material layer PA2 and the third preliminary active material layer PA3 can have a single, uniform shape and the active material is impregnated in a porous membrane PW. After the second positive electrode slurry AM is coated and cured, 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.

[0134] 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 capable of being 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.

[0135] 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 film that maintains a given shape without being supported by another substrate. In an example embodiment, the composite layer CMM can have a shape composed of… Figure 12B The shape depicted is formed by removing the release membrane RF, adhesive BD, and preliminary porous membrane PWA from the first region A1.

[0136] Composite layer CMMs can have a substantially uniform thickness. Composite layer CMMs can have a thickness ranging from about 50 μm to about 500 μm. For example, the thickness of a composite layer CMM can range from about 60 μm to about 300 μm, from about 80 μm to about 200 μm, or from about 100 μm to about 200 μm.

[0137] Figures 13 to 15 A cross-sectional view is shown illustrating a method for manufacturing a positive electrode for an all-solid-state battery according to an exemplary embodiment of the present disclosure.

[0138] Reference Figure 13 and Figure 14 A composite layer CMM can be formed on the first preliminary active material layer PA1 formed on the positive electrode current collector 110. For example, the composite layer CMM can be formed according to the bonding... Figure 12A and Figure 12B The composite layer CMM is formed according to the detailed description and can be disposed on a first preliminary active material layer PA1 located on one side of the positive electrode current collector 110. When the composite layer CMM is disposed on the first preliminary active material layer PA1, a second preliminary active material layer PA2 can be disposed adjacent to the first preliminary active material layer PA1.

[0139] Reference Figure 14 and Figure 15After forming the composite layer CMM, the stacked (e.g., sequentially stacked) positive electrode current collector 110, first preliminary active material layer PA1 and composite layer CMM can be integrally laminated together. The pressing unit PRU can press the stacked (e.g., sequentially stacked) positive electrode current collector 110, first preliminary active material layer PA1 and composite layer CMM.

[0140] The pressing unit PRU may include a pressing roller. The pressing unit PRU can press the positive electrode current collector 110, the first preliminary active material layer PA1 on the positive electrode current collector 110, and the composite layer CMM on the first preliminary active material layer PA1.

[0141] After the pressing process using the pressing unit PRU, a positive electrode active material layer 120 can be formed. The positive electrode active material layer 120 may include multiple sublayers P1, P2, and P3. The positive electrode active material layer 120 may include a first sublayer P1 located on one side of the positive electrode current collector 110, a second sublayer P2 between the first sublayer P1 and the porous membrane PW, and a third sublayer P3 located on the porous membrane PW. The third sublayer P3 may be spaced apart from the second sublayer P2 across the porous membrane PW. The first sublayer P1 may originate from a first preliminary active material layer PA1, the second sublayer P2 may originate from a second preliminary active material layer PA2, and the third sublayer P3 may originate from a third preliminary active material layer PA3.

[0142] The first sublayer P1 and the second sublayer P2 can have a single, uniform shape. An interface may not be separately provided between the first sublayer P1 and the second sublayer P2, and the active material included in the first sublayer P1 and the active material included in the second sublayer P2 can be mixed with each other to provide a single mixed active material layer with a single, uniform shape. Although the first sublayer P1 and the second sublayer P2 are derived from the first preliminary active material layer PA1 and the second preliminary active material layer PA2, respectively, the pressing process can force the first sublayer P1 and the second sublayer P2 to mix with each other to have a single, uniform shape.

[0143] Although not shown in detail, the active material included in the second sublayer P2 can be mixed with the active material permeating into the pores of the porous membrane PW, thereby providing a mixed active material layer with a single, uniform shape. Similarly, the active material included in the third sublayer P3 can be mixed with the active material permeating into the pores of the porous membrane PW, thereby providing a mixed active material layer with a single, uniform shape. For example, in the positive electrode active material layer 120, the active material included in the first sublayer P1, the active material included in the second sublayer P2, the active material included in the third sublayer P3, and the active material permeating into the pores of the porous membrane PW can be mixed with each other to produce a mixed active material layer.

[0144] Figure 17 This is a flowchart illustrating a method for manufacturing a positive electrode for an all-solid-state battery according to various example embodiments. In the example, method 1700 includes operations 1710, 1720, 1730, 1740, and 1750. Operation 1710 includes preparing a first positive electrode slurry comprising first solid electrolyte particles. Operation 1720 includes preparing a second positive electrode slurry comprising second solid electrolyte particles. For example, the average particle size of the first solid electrolyte particles differs from the average particle size of the second solid electrolyte particles. In another example, the average particle size of the second solid electrolyte particles is larger than the average particle size of the first solid electrolyte particles. Operation 1730 includes coating the first positive electrode slurry onto a positive electrode current collector to form a first preliminary active material layer.

[0145] Operation 1740 includes placing a composite layer comprising a porous membrane on a first preliminary active material layer. For example, the step of placing the composite layer includes forming the composite layer by providing a preliminary porous membrane and coating the preliminary porous membrane with a second positive electrode slurry to form the composite layer. In one example, the porous membrane is formed by permeating a positive electrode active material into the preliminary porous membrane. For example, the thickness of the preliminary porous membrane is in the range of about 5 μm to about 15 μm. In another example, the pore size in the preliminary porous membrane is in the range of about 50 nm to about 500 nm. In another example, the permeability of the preliminary porous membrane is in the range of about 50% to about 99%. In yet another example, the composite layer includes a second preliminary active material layer, a third preliminary active material layer, and a porous membrane between the second and third preliminary active material layers, and the positive electrode current collector, the first preliminary active material layer, and the composite layer are integrally pressed together such that the first, second, and third preliminary active material layers are formed into a single uniform shape to form a mixed active material layer. Operation 1750 includes pressing together a positive electrode current collector, a first preliminary active material layer, and a composite layer.

[0146] Some exemplary embodiments and comparative examples of this disclosure are described below. However, the embodiments below are merely examples, and this disclosure is not limited to the exemplary embodiments discussed below.

[0147] Example 1 Manufacturing the positive electrode: Preparing LiNi 0.8 Co 0.15 Mn 0.05 O2 (NCM) powder was used as the positive electrode active material. An average particle size (D) was prepared. 50 The first solid electrolyte particles of 1 μm sulfosilver germanite type (e.g., Li6PS5Cl) were used as the solid electrolyte, polyvinylidene fluoride (PVDF) was prepared as the binder, and carbon nanofibers (CNF) were prepared as the conductive material.

[0148] A first positive electrode slurry is prepared by mixing the positive electrode active material, solid electrolyte, conductive material, and binder in an N-methylpyrrolidone solvent at a weight ratio of approximately 85:13.5:0.5:1. The first positive electrode slurry is coated onto an aluminum positive electrode current collector and dried, and then pressed to manufacture a first positive electrode plate.

[0149] In addition, besides replacing the first solid electrolyte particles with an average particle size (D... 50 Apart from the difference of 2 μm sulfogermanium ore type second solid electrolyte particles (Li6PS5Cl), the second positive electrode slurry was prepared using the same method as the first positive electrode slurry.

[0150] The second positive electrode slurry was coated onto a 10 μm thick porous nonwoven fabric to prepare a positive electrode active material composite layer in the form of a self-standing membrane. The prepared positive electrode active material composite layer was stacked on the first positive electrode plate so that the porous nonwoven fabric was close to the presence of the positive electrode current collector, and then pressed and mixed to manufacture the positive electrode.

[0151] A pressing process is performed using pressure rollers at 25°C, where the linear pressure of the pressure rollers is controlled at 2.3 tons, and the gap between the upper and lower rollers is adjusted to zero to press the positive electrode. This results in a reduced thickness of the pressed positive electrode, achieving a high mixture density. The positive electrode is manufactured such that the positive electrode active material disposed on the positive electrode current collector side has a concentration of 45 mg / cm³. 2 The load level.

[0152] The total thickness of the manufactured positive electrode is 150 μm, and a distance of 90 μm is provided between the positive electrode current collector and the porous nonwoven fabric.

[0153] Preparation of solid electrolyte layer: Average particle size (D) 50 3 μm sterhenite-type third solid electrolyte particles (e.g., Li6PS5Cl) were 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.

[0154] Manufacturing the negative electrode: 90wt% silver (Ag) nanoparticles (D 50A negative electrode coating slurry was prepared by mixing 10 wt% carbon black (60 nm) and 10 wt% carbon black in an aqueous solvent. The carbon black was a mixture of single particles with a particle size of 38 nm and secondary particles with a particle size of 275 nm, wherein primary particles with a particle size of 76 nm were aggregated in the secondary particles. The slurry was coated onto a stainless steel foil current collector and then dried to produce a negative electrode comprising a negative electrode coating layer with a thickness of 12 μm and a current collector with a thickness of 10 μm.

[0155] All-solid-state batteries: A solid-state battery is fabricated by stacking a positive electrode, a solid electrolyte layer, and a negative electrode, and then subjecting the mixture to isostatic pressing at 85°C and 500 MPa for approximately 30 minutes.

[0156] Example 2 The positive electrode, solid electrolyte layer, negative electrode, and all-solid-state battery are each manufactured independently using the same method as in Example 1, except that: 1) when preparing the first positive electrode slurry, an average particle size (D) is used. 50 1) The first solid electrolyte particles are 1.5 μm in size; and 2) When preparing the second positive electrode slurry, the average particle size (D) is used. 50 The second solid electrolyte particles are 2.5 μm in size.

[0157] Comparison Example 1 The positive electrode, solid electrolyte layer, negative electrode, and all-solid-state battery were independently manufactured using the same method as in Example 1, except that when preparing the second positive electrode slurry, the average particle size (D) was used. 50 The first solid electrolyte particle with a diameter of 1.0 μm replaces the average particle size (D). 50 The second solid electrolyte particles are 2.0 μm in size (e.g., Li6PS5Cl).

[0158] For example, unlike Embodiment 1 where the first and second solid electrolyte particles are included in the positive electrode, only the first solid electrolyte particles are included in the positive electrode.

[0159] Comparison Example 2 The positive electrode was manufactured using the same method as in Example 1, except that: during the manufacture of the positive electrode, a self-standing film-like composite layer of positive electrode active material was stacked on the first positive electrode plate, the porous nonwoven fabric was kept away from the positive electrode current collector, and it was pressed to a loading level of 56 mg / cm². 2 .

[0160] The total thickness of the manufactured positive electrode is 150 μm, and a distance of 140 μm is provided between the positive electrode current collector and the porous nonwoven fabric.

[0161] Evaluation 1: Ionic conductivity of the positive electrode The ionic conductivity of each of the batteries according to the Examples and Comparative Examples was measured as follows. Positive electrodes from each of Examples 1 and Comparative Example 1 were sampled with a thickness of 150 μm and a diameter of 12 mm. A two-probe method was performed using an impedance analyzer (Solartron 1260A impedance / gain phase analyzer) to measure impedance and obtain a Nyquist plot (25°C, frequency range of 0.1 Hz to 1 MHz, and amplitude voltage of 10 mV). The bulk resistance was obtained from the arc of the Nyquist plot with respect to the impedance measurements, and the ionic resistance was calculated considering the area and thickness of the sample. The results are shown in Table 1 below. Figure 16 middle.

[0162] Table 1:

[0163] Referring to Table 1, it can be observed that the ionic conductivity of the positive electrode according to each of Examples 1 and 2 is less than that of the positive electrode according to each of Comparative Examples 1 and 2. For example, it can be observed that the positive electrode according to each of Examples 1 and 2 exhibits the desired or improved ionic conductivity. Therefore, it can be determined that the ionic conductivity increases when the average particle size of the solid electrolyte particles in the positive electrode active material composite layer is greater than the average particle size of the solid electrolyte particles in the first positive electrode plate.

[0164] Evaluation 2: Cycle life characteristics Each of the all-solid-state batteries according to Examples 1 and 2, and Comparative Examples 1 and 2, was charged and discharged. The first charge / discharge cycle was performed under the following conditions: charging (0.33C CC / CV charging at 4.25V, 0.05C cutoff) and discharging (0.33C CC discharging at 3.0V cutoff). The second charge / discharge cycle and subsequent charge / discharge cycles were performed under the following conditions: charging (1.0C CC / CV charging at 4.25V, 0.05C cutoff) and discharging (0.5C CC discharging at 3.0V cutoff). After continuous charge / discharge cycles, the number of cycles (cyc) at which 80% capacity retention was achieved was defined as the cycle life characteristic. The capacity retention of the nth cycle was calculated according to Formula 2 below.

[0165] Formula 2: Capacity retention rate (SOH) (%) = [Discharge capacity in the nth cycle / Discharge capacity in the 1st cycle] × 100 Table 2:

[0166] Referring to Table 2, it can be determined that, unlike Example 1, the all-solid-state battery of Comparative Example 2 (in which the self-standing film-type composite layer is flipped and stacked on the first positive electrode plate) has significantly reduced cycle life characteristics. Furthermore, it can be determined that, in the case of all-solid-state batteries of Examples 1 and 2 where the solid electrolyte particles in the positive electrode have different sizes, the cycle life characteristics are improved compared to the all-solid-state battery of Comparative Example 1 where the solid electrolyte particles in the positive electrode have the same size.

[0167] In the positive electrode for an all-solid-state battery conceived according to the present invention and in an all-solid-state battery comprising the positive electrode, a high loading level can be achieved due to a porous membrane disposed in the positive electrode active material layer and the active material impregnated in the porous membrane. Therefore, an all-solid-state battery comprising a positive electrode according to an exemplary embodiment can exhibit a high current density. Furthermore, the average particle size of the solid electrolyte particles can vary in different portions of the positive electrode active material layer, thus improving ionic conductivity.

[0168] The method for manufacturing a positive electrode for an all-solid-state battery according to an example of the present invention can be low-manufacturing-difficult and suitable for mass production.

Claims

1. A positive electrode for an all-solid-state battery, the positive electrode comprising: Positive electrode current collector; A positive electrode active material layer is disposed on the positive electrode current collector; as well as A porous membrane is present in the positive electrode active material layer. The positive electrode active material layer comprises positive electrode active material particles and solid electrolyte particles. The positive electrode active material layer has a first portion and a second portion that span different parts of the porous membrane. The first portion is located between the positive electrode current collector and the porous membrane, and The average particle size of the solid electrolyte particles in the first part is different from that in the second part.

2. The positive electrode according to claim 1, wherein: The solid electrolyte particles include a first solid electrolyte particle and a second solid electrolyte particle. The first part includes the first solid electrolyte particles. The second part includes the second solid electrolyte particles, and The average particle size of the second solid electrolyte particles is greater than the average particle size of the first solid electrolyte particles.

3. The positive electrode according to claim 2, wherein, The first part also includes the second solid electrolyte particles.

4. The positive electrode according to claim 2, wherein, The average particle size of the first solid electrolyte particles is equal to or less than 1.5 μm.

5. The positive electrode according to claim 2, wherein, The average particle size of the second solid electrolyte particles is in the range of 1.5 μm to 2.5 μm.

6. The positive electrode according to claim 1, wherein, The positive electrode active material layer includes: The first sublayer is on the positive electrode current collector; A second sublayer, located between the first sublayer and the porous membrane; and The third sublayer, on the porous membrane Wherein, the first sub-layer and the second sub-layer are in the first part, and The third sub-layer is located in the second part.

7. The positive electrode according to claim 6, wherein: The first sublayer includes first solid electrolyte particles. At least one of the second sublayer and the third sublayer comprises a second solid electrolyte particle, and The average particle size of the second solid electrolyte particles is greater than the average particle size of the first solid electrolyte particles.

8. The positive electrode according to claim 1, wherein, The porous membrane includes at least one of polyester, polypropylene, and polyethylene.

9. The positive electrode according to claim 1, wherein, The thickness of the porous membrane is in the range of 5 μm to 15 μm.

10. The positive electrode according to claim 1, wherein, The positive electrode active material layer also includes a binder. The adhesive includes at least one of styrene-butadiene rubber, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polyvinyl alcohol, vinylidene fluoride / hexafluoropropylene copolymer, polyvinylidene fluoride / hexafluoropropylene copolymer, polyacrylonitrile, and polymethyl methacrylate.

11. The positive electrode according to claim 1, wherein, Based on the positive electrode active material layer on one side of the positive electrode current collector, the loading level of the positive electrode active material particles is equal to or greater than 35 mg / cm³. 2 .

12. An all-solid-state battery, the all-solid-state battery comprising: The positive electrode according to any one of claims 1 to 11; The negative electrode is opposite to the positive electrode. as well as A solid electrolyte layer is located between the positive electrode and the negative electrode.

13. The all-solid-state battery according to claim 12, wherein, The solid electrolyte layer includes third solid electrolyte particles. The average particle size of the third solid electrolyte particles is in the range of 2.5 μm to 5 μm.

14. A method for manufacturing a positive electrode for an all-solid-state battery, the method comprising the steps of: Prepare a first positive electrode slurry comprising first solid electrolyte particles; Prepare a second positive electrode slurry comprising second solid electrolyte particles; The first positive electrode slurry is coated onto the positive electrode current collector to form a first preliminary active material layer; A composite layer including a porous membrane is placed on the first preliminary active material layer; as well as The positive electrode current collector, the first preliminary active material layer, and the composite layer are pressed and stacked together. The step of placing the composite layer includes forming the composite layer by the following steps: providing a preliminary porous membrane; and coating the preliminary porous membrane with a second positive electrode paste to form the composite layer. The average particle size of the first solid electrolyte particles is different from that of the second solid electrolyte particles.

15. The method according to claim 14, wherein, The average particle size of the second solid electrolyte particle is greater than the average particle size of the first solid electrolyte particle.

16. The method of claim 14, wherein: The composite layer includes a second preliminary active material layer, a third preliminary active material layer, and the porous membrane between the second preliminary active material layer and the third preliminary active material layer. The positive electrode current collector, the first preliminary active material layer, and the composite layer are pressed together as a whole, so that the first preliminary active material layer, the second preliminary active material layer, and the third preliminary active material layer are formed into a single uniform shape to form a mixed active material layer.

17. The method of claim 14, wherein, The porous membrane is formed by permeating the positive electrode active material into the preliminary porous membrane.

18. The method according to claim 14, wherein, The thickness of the initial porous membrane is in the range of 5 μm to 15 μm.

19. The method of claim 14, wherein, The pore size in the preliminary porous membrane is in the range of 50 nm to 500 nm.

20. The method of claim 14, wherein, The permeability of the preliminary porous membrane is in the range of 50% to 99%.

Images