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

Abstract

The present disclosure relates to a positive electrode for an all-solid-state battery. The present disclosure describes a positive electrode current collector and a positive electrode active material layer on the positive electrode current collector. The positive electrode current collector includes a body portion and a positive electrode tab protruding from the body portion in one direction. The positive electrode active material layer is disposed on the body portion, and the positive electrode active material layer includes a positive electrode active material and a solid electrolyte. The body portion includes a first end portion and a second end portion opposite each other in one direction. The first end portion straddles a boundary between the positive electrode tab and the body portion, and the body portion includes a tab-adjacent portion extending from the first end portion toward the second end portion.

Description

[0001] This application claims priority to Korean Patent Application No. 10-2025-0005348, filed on January 14, 2025, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates to all-solid-state batteries. Background Technology

[0003] With increasing industrial demand, there is a strong push for the development of batteries with high energy density and high safety. For example, lithium-ion batteries are widely commercialized and used not only in consumer electronics and communication devices but also in the automotive industry. In automotive applications, battery safety is paramount due to its direct impact on user safety.

[0004] All-solid-state batteries, which use solid electrolytes instead of liquid electrolytes, appear to be a promising alternative. Unlike conventional lithium-ion batteries that contain flammable organic solvents, all-solid-state batteries significantly reduce the risk of fire or explosion, even in the event of a short circuit. Therefore, all-solid-state batteries offer a substantial improvement in safety compared to lithium-ion batteries that use liquid electrolytes. Summary of the Invention

[0005] This disclosure can reduce or prevent localized irreversible deposition caused by bias current flow in the positive electrode. Furthermore, this disclosure can improve battery life by maintaining the electrical and chemical properties of the positive electrode.

[0006] Example embodiments of this disclosure may include a positive electrode for an all-solid-state battery, the positive electrode comprising a positive electrode current collector and a layer of positive electrode active material on the positive electrode current collector.

[0007] The positive electrode current collector may include a main body portion and a positive electrode terminal protruding from the main body portion in one direction. A positive electrode active material layer may be disposed on the main body portion, and the positive electrode active material layer may include a positive electrode active material and a solid electrolyte.

[0008] The main body portion may include a first end and a second end opposite to each other in one direction. The first end may span the boundary between the positive electrode tab and the main body portion. The main body portion may include adjacent portions of the tab extending from the first end to the second end.

[0009] The positive electrode active material layer may include a first region on the portion adjacent to the terminal block and a second region as the remaining portion other than the first region.

[0010] The content of solid electrolyte in the first region may be less than or equal to about 10 wt%, and the content of solid electrolyte in the second region may be greater than or equal to about 10 wt%. The content of solid electrolyte in the first region may be less than the content of solid electrolyte in the second region.

[0011] Example embodiments of this disclosure may include an all-solid-state battery, the all-solid-state battery including a positive electrode, a negative electrode and a solid electrolyte layer, the negative electrode including a negative electrode current collector and a negative electrode coating on the negative electrode current collector, and the solid electrolyte layer between the positive electrode and the negative electrode.

[0012] Example embodiments of this disclosure may include a method for manufacturing a positive electrode for an all-solid-state battery, the method comprising: forming a first active material region and a second active material region arranged side-by-side in the width direction of a metal substrate; forming a positive electrode sheet by drying the first active material region and the second active material region; and forming a positive electrode composite layer by dicing the positive electrode sheet.

[0013] Each of the first active material region and the second active material region may include a positive electrode active material and a solid electrolyte. The positive electrode sheet may include a first uncoated region formed on one side thereon, and the first active material region may be adjacent to the first uncoated region in the width direction.

[0014] The positive electrode composite layer may include an electrode tab formed by cutting a first uncoated region and a first positive electrode active material layer including a first active material region and a second active material region.

[0015] The content of solid electrolyte in the first active material region may be less than or equal to about 10 wt%, and the content of solid electrolyte in the second active material region may be greater than or equal to about 10 wt%. The content of solid electrolyte in the first region may be less than the content of solid electrolyte in the second region. Attached Figure Description

[0016] Figure 1 and Figure 2 This is a plan view of the positive electrode for an all-solid-state battery according to an exemplary embodiment of the present disclosure.

[0017] Figure 3 It is along Figure 1 or Figure 2 The sectional view taken by line A-A' in the middle.

[0018] Figure 4 yes Figure 3 An enlarged view of region "M" in the image.

[0019] Figure 5This is a cross-sectional view of the positive electrode for an all-solid-state battery according to an exemplary embodiment of the present disclosure.

[0020] Figure 6 This is a cross-sectional view of the positive electrode for an all-solid-state battery according to an exemplary embodiment of the present disclosure.

[0021] Figure 7 This is a cross-sectional view of the positive electrode for an all-solid-state battery according to an exemplary embodiment of the present disclosure.

[0022] Figure 8 and Figure 9 This is a cross-sectional view of an all-solid-state battery cell according to an exemplary embodiment of the present disclosure.

[0023] Figures 10 to 13 A method for manufacturing a positive electrode according to an example embodiment of the present disclosure is shown.

[0024] Figure 14A The appearance of an all-solid-state battery according to an example embodiment is shown.

[0025] Figure 14B This is a cross-sectional SEM image of an all-solid-state battery according to one embodiment.

[0026] Figure 15A The appearance of an all-solid-state battery, based on a comparative example, is shown.

[0027] Figure 15B It is a cross-sectional SEM image of an all-solid-state battery based on a comparative example.

[0028] Figure 16 This is a flowchart illustrating a method for manufacturing a positive electrode for an all-solid-state battery according to an example embodiment. Detailed Implementation

[0029] To provide a full understanding of the structure and effects of this disclosure, some exemplary embodiments have been described with reference to the accompanying drawings. However, this disclosure is not limited to the following exemplary embodiments and can be implemented in various forms. The exemplary embodiments are provided merely to illustrate this disclosure and to enable those skilled in the art to fully understand its scope.

[0030] In this specification, when an element is described as being "on" another element, the element may be "directly on" said other element, or one or more intervening elements may be present between them. In the accompanying drawings, certain thicknesses may be exaggerated to better illustrate technical details. Throughout the specification, the same reference numerals denote the same elements.

[0031] The exemplary embodiments described herein can be illustrated using sectional views and / or plan views presented as idealized examples of this disclosure. For clarity, the thickness of layers and regions in the figures may be exaggerated. The regions shown in the figures are for illustrative purposes and should not be construed as limiting the scope of this disclosure. Although terms such as “first,” “second,” and “third” may be used to describe various elements, these terms are used only to distinguish elements and do not imply any particular order or hierarchy. The exemplary embodiments described and illustrated herein include complementary variations.

[0032] The terminology used in this specification is for illustrative purposes only and is not intended to limit this disclosure. Unless otherwise expressly stated, the singular form may also include the plural form. The term "comprising / including" and its variations do not exclude the presence or addition of one or more other components.

[0033] In this specification, the phrase "combinations thereof" may refer to mixtures, stacks, complexes, copolymers, alloys, blends, or reaction products.

[0034] Unless otherwise specifically defined, the term "particle size" refers to the average particle size. Particle size can be expressed as the median particle size (D50) corresponding to the diameter of the 50% volume percent of particles in the cumulative particle size distribution. The average particle size (D50) can be measured using widely known methods, such as particle size analyzers, transmission electron microscopy (TEM) imaging, or scanning electron microscopy (SEM) imaging. Alternatively, dynamic light scattering can be used, in which particle counts within a size range are analyzed to calculate the average particle size (D50). Furthermore, laser scattering can be employed, in which target particles are dispersed in a solvent, introduced into a laser scattering particle measurement device (e.g., the MT3000 from Microtrac), irradiated with ultrasound at 28 kHz and 60 W, and subsequently analyzed to determine the D50 value based on the 50% cumulative particle size distribution.

[0035] The phrases “A or B”, “at least one of A and B (species / man)”, “at least one of A or B (species / man)”, “A, B or C”, “at least one of A, B and C (species / man)”, and “at least one of A, B or C (species / man)” include any one of the listed elements or all possible combinations thereof.

[0036] When the terms “about” or “substantially” are used in conjunction with numerical values ​​in this specification, it is intended that the relevant numerical values ​​include 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%.

[0037] All-solid-state batteries An all-solid-state battery according to an example embodiment of this disclosure may include a cell. A cell may refer to the smallest unit required to operate a battery system. A cell may include the basic components of an all-solid-state battery. For example, a cell may include a positive electrode, a negative electrode, and a solid electrolyte layer between the positive and negative electrodes. In some cases, a cell may also include additional functional layers, such as an adhesion enhancement layer, disposed between the positive electrode and the solid electrolyte layer or between the negative electrode and the solid electrolyte layer. An all-solid-state battery may include multiple cell units.

[0038] Figure 1 and Figure 2 This is a plan view of the positive electrode CSH according to an exemplary embodiment of the present disclosure. Figure 3 It is along Figure 1 or Figure 2 The cross-sectional view of the positive electrode CSH taken by line A-A'. Figure 4 yes Figure 3 An enlarged view of region "M" in the diagram. The positive electrode CSH according to an exemplary embodiment of this disclosure may include a positive electrode current collector COL1 and a positive electrode active material layer CML disposed on the positive electrode current collector COL1. The positive electrode active material layer CML may include a positive electrode active material CAC and a solid electrolyte SEP. Although not shown, the positive electrode active material layer CML may also include a binder and / or a conductive material.

[0039] The positive electrode current collector COL1 can provide a reference surface on which the positive electrode active material layer CML is disposed. The positive electrode current collector COL1 may include a plate or foil, which includes at least one of, 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), and alloys thereof.

[0040] To increase the adhesion between the positive electrode current collector COL1 and the positive electrode active material layer CML, a carbon-containing layer having a thickness in the range of about 0.1 μm to about 4 μm or about 1 μm to about 3 μm can be further disposed between the positive electrode current collector COL1 and the positive electrode active material layer CML. For example, the carbon-containing layer may include a relatively large amount of adhesive. The carbon-containing layer can improve the adhesion between the positive electrode current collector COL1 and the positive electrode active material layer CML. The carbon-containing layer can improve the conductivity of the positive electrode CSH.

[0041] The positive electrode active material CAC of the positive electrode active material layer CML may include materials capable of reversibly absorbing and desorbing lithium ions. The positive electrode active material CAC may include multiple particles. The positive electrode active material CAC may include, but is not limited to, 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. Each or at least one of the positive electrode active materials CAC may be or include a single material or a mixture of two or more materials.

[0042] 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), Lia 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-f The compound represents one of Fe2(PO4)3 (where 0≤f≤2) and LiFePO4. In the above compounds, "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.

[0043] The positive electrode active material CAC may 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" may refer to a structure in which oxygen atom layers and metal atom layers are alternately and regularly arranged in the <111> direction of the cubic rock salt-type structure, where each atom layer forms a two-dimensional plane. The term "cubic rock salt-type structure" may refer to the sodium chloride (NaCl)-type structure, which is a type of crystal structure. For example, it has a structure in which face-centered cubic lattices (FCCs) each formed by cations and anions are offset by 1 / 2 (half) of the edges of the unit lattice. The lithium transition metal oxide having a layered rock salt-type structure may 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 CAC includes a ternary lithium transition metal oxide having a layered rock salt-type structure, the unit cell may have an increased energy density and improved thermal stability.

[0044] The compounds included in the positive electrode active material CAC may be covered by a coating (not shown). The positive electrode active material CAC may be used as a mixture of the compound and the compound with the coating added. The coating added to the surface of the positive electrode active material may include, for example, at least one of oxides, hydroxides, hydroxyoxides, carbonate oxy salts, and bicarbonate salts of the coating elements discussed below. The compounds constituting the coating may be amorphous or crystalline. The coating elements included in the coating may include at least one of Mg, Al, Co, K, Na, Ca, Si, Ti, V, Sn, Ge, Ga, B, As, Zr, and mixtures thereof. The coating may include, for example, Li2O-ZrO2 (LZO). The method for forming the coating may be determined within any method that does not adversely affect the physical properties of the positive electrode active material. The method for forming the coating may include, for example, spraying or dipping.

[0045] In an exemplary embodiment, the coating may be present locally on the surface of the positive electrode active material CAC or exist in an aggregated state. In another exemplary embodiment, the coating may be formed with a uniform thickness on the entire surface of the positive electrode active material CAC. For example, the standard deviation of the coating thickness may be about 10% or less or about 5% or less with respect to the diameter of the positive electrode active material CAC.

[0046] Coatings can form buffer or protective layers. Coatings can facilitate the movement of lithium ions on the surface of the positive electrode active material (CAC) and improve interfacial resistance by reducing reactivity with the solid electrolyte. Coatings can improve the ionic conductivity of the positive electrode active material (CAC). Coatings can improve the electrochemical characteristics of the battery by effectively protecting the positive electrode active material (CAC). Coatings can mitigate the volume changes of the positive electrode active material (CAC) caused by charge / discharge and improve structural stability.

[0047] For example, when the positive electrode active material (CAC) includes a ternary lithium transition metal oxide containing nickel (Ni) (such as NCA or NCM), the capacity density of the cell can be increased, and metal dissolution of the positive electrode active material during the charging state can be reduced. As a result, the cycle characteristics of the cell under the charging state can be improved. "Cycling characteristics" can refer to properties indicating the degree of degradation of a cell due to charging and discharging. For example, a cell with high cycle characteristics degrades less due to charging and discharging, while a cell with low cycle characteristics degrades more due to charging and discharging.

[0048] Positive electrode active material CAC can, for example, have spherical or elliptical particle shapes. There are no limitations on the particle size and content of positive electrode active material CAC. For example, the average particle size of positive electrode active material CAC analyzed by scanning electron microscopy (SEM) images can range from about 200 nm to about 25 μm.

[0049] The solid electrolyte epoxide (SEP) of the positive electrode active material layer (CML) can have a particulate shape. The SEP can be dispersed between the positive electrode active materials (CAC). The SEP can include sulfide-based solid electrolytes with desired or improved lithium-ion conductivity. Sulfide-based solid electrolytes can include at least one of the following: Li₂S-P₂S₅; Li₂S-P₂S₅-Li x (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; Li2S-P2S5-Z m S n (Where m and n are each positive integers, and "Z" is or includes at least one of Ge, Zn, and Ga); Li2S-GeS2; Li2S-SiS2-Li3PO4; Li2S-SiS2-Li p MO q(Where p and q are each positive integers, and "M" is or includes at least 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 (where 0 ≤ x ≤ 2).

[0050] Sulfide solid electrolytes may be or include, for example, Li 7-x PS 6-x Cl x (0≤x≤2), Li 7-x SP 6-x Br x (0≤x≤2) and Li 7-x PS 6-x I x The sulfide solid electrolyte may include at least one of the following: (0≤x≤2) silver-germanium sulfide compounds. Specifically, the sulfide solid electrolyte may include at least one of the following: silver-germanium sulfide compounds: Li6PS5Cl, Li6PS5Br, and Li6PS5I.

[0051] Optionally, sulfide-based solid electrolytes may include Li 7-a-c M a PS 6-c X c A sulfide-germanium ore type compound (0≤a≤2, 0≤c≤2). In the above chemical formula, X can be or include at least one of F, Br, Cl, I and combinations thereof. M may include at least one of scandium (Sc), yttrium (Y), titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), technetium (Tc), rhenium (Re), iron (Fe), ruthenium (Ru), osmium (Os), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt), copper (Cu), silver (Ag), gold (Au), zinc (Zn), cadmium (Cd), mercury (Hg), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), arsenic (As), antimony (Sb), bismuth (Bi), and combinations thereof.

[0052] The density of the sulfide-germanium ore-type solid electrolyte (SEP) can range from about 1.5 g / cc to about 2.0 g / cc. Because the sulfide-germanium ore-type SEP has a density of about 1.5 g / cc or greater, the internal resistance of the all-solid-state battery can be reduced, and it can prevent or hinder the solid electrolyte membrane from being penetrated and short-circuited due to the formation of lithium dendrites. The elastic modulus of the solid electrolyte SEP can, for example, range from about 15 GPa to about 35 GPa.

[0053] The solid electrolyte epoxide (SEP) in the positive electrode active material layer (CML) can have a smaller average particle size than the solid electrolyte in the solid electrolyte layer, which will be described later. For example, the average particle size of the SEP in the positive electrode active material layer (CML) can be about 90% or less, about 80% or less, about 70% or less, about 60% or less, about 50% or less, about 40% or less, about 30% or less, or about 20% or less of the average particle size of the solid electrolyte in the solid electrolyte layer. The average particle size can be the median diameter measured using a laser particle size distribution analyzer.

[0054] The positive electrode active material layer (CML) may include a conductive material. The conductive material can be conductive without causing undesirable chemical changes within the cell, thereby increasing the conductivity of the positive electrode active material (CAC) and the solid electrolyte (SEP). The conductive material may include carbon-based materials. Specifically, the conductive material may include at least one of, for example, graphite, carbon black, acetylene black, carbon nanofibers, and carbon nanotubes.

[0055] The positive electrode active material layer CML may include an adhesive. The adhesive can bond the positive electrode active material CAC, the solid electrolyte SEP, and the conductive material within the positive electrode active material layer CML. The adhesive may include materials that improve the adhesion between the positive electrode active material layer CML and the positive electrode current collector COL1. 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.

[0056] In an example embodiment, the content of the positive electrode active material CAC relative to the total weight of the positive electrode active material layer CML can be in the range of about 10 wt% to about 99 wt%, about 30 wt% to about 80 wt%, about 40 wt% to about 70 wt%, about 40 wt% to about 50 wt%, about 60 wt% to about 90 wt%, or about 70 wt% to about 90 wt%.

[0057] In an example embodiment, the content of solid electrolyte (SEP) in the positive electrode active material layer (CML) can be in the range of about 5 wt% to about 70 wt%, about 10 wt% to about 70 wt%, about 10 wt% to about 60 wt%, about 5 wt% to about 30 wt%, about 5 wt% to about 25 wt%, or about 10 wt% to about 40 wt%, relative to the total weight of the positive electrode active material layer (CML).

[0058] In addition to the positive electrode active material CAC, solid electrolyte SEP, conductive material and binder mentioned above, the positive electrode active material layer CML may also include one or more additives, such as fillers, coating agents, dispersants and ionic conductive agents.

[0059] Return to reference Figures 1 to 3 The positive electrode according to an exemplary embodiment of this disclosure is described in more detail below. (Refer to...) Figure 1 The positive electrode current collector COL1 may include a main body portion MBD and a positive electrode terminal piece CTB. The main body portion MBD may provide an area where the positive electrode active material layer CML is disposed. The positive electrode terminal piece CTB may refer to an uncoated portion protruding from the main body portion MBD in one direction. That is, the positive electrode active material layer CML may be disposed on the main body portion MBD, but not on the positive electrode terminal piece CTB.

[0060] For reference Figure 1 In the example embodiment shown, the positive electrode contact CTB protrudes in the second direction D2. The main body portion MBD may include a first end ED1 and a second end ED2 opposite to each other in the second direction D2. Each of the first end ED1 and the second end ED2 may refer to one end of the main body portion MBD. The first end ED1 may span the boundary between the positive electrode contact CTB and the main body portion MBD. That is, based on the first end ED1, the positive electrode current collector COL1 can be divided into the main body portion MBD and the positive electrode contact CTB.

[0061] like Figure 2 As shown, even when the specific positions of the positive electrode connector CTB differ, the main body MBD and the positive electrode connector CTB can still be distinguished based on the first end ED1. Regardless of the position of the positive electrode connector CTB, the positive electrode connector CTB can protrude in the second direction D2 in the same manner.

[0062] The positive electrode tab (CTB) can be electrically connected to the lead tab, allowing the CTB to be connected to the outside of the cell. The CTB can transfer the current generated in the positive electrode to external circuitry. The CTB can stably provide current flow between the inside and outside of the cell. However, the region of the positive electrode active material layer (CML) adjacent to the CTB may experience a localized reduction in current density.

[0063] Due to the biased use of the positive electrode active material CAC in certain regions of the positive electrode active material layer CML, irreversible lithium deposition may occur. Irreversible lithium deposition may degrade the structural stability of the positive electrode CSH and potentially lead to short circuits. Furthermore, these problems may become more severe when increasing the electrode loading or thickness to enhance the capacity of the all-solid-state battery.

[0064] To address these issues, exemplary embodiments of this disclosure aim to uniformly maintain the overall electrochemical stability of the electrode by introducing an electrode structure comprising multiple regions with different compositions. The structural characteristics of the positive electrode according to exemplary embodiments of this disclosure are described in detail below.

[0065] The main body portion MBD may include a tab adjacent portion ADJ adjacent to the positive electrode tab CTB. For example, the main body portion MBD may include a tab adjacent portion ADJ extending from the first end ED1 toward the second end ED2. The tab adjacent portion ADJ may be a region adjacent to the first end ED1.

[0066] In an example embodiment, the adjacent portion ADJ of the terminal block can be defined as an area having an area of ​​approximately 20% of the total area of ​​the main portion MBD. That is, the adjacent portion ADJ of the terminal block extends from the first end ED1 toward the second end ED2 and can have an area of ​​approximately 20% of the area of ​​the main portion MBD.

[0067] In an example embodiment, the adjacent portion ADJ of the connector can be a region with a substantially constant width based on the second direction D2. For example, the adjacent portion ADJ of the connector can refer to a region extending a second length L2 from the first end ED1 toward the second end ED2. That is, the width of the adjacent portion ADJ of the connector relative to the second direction D2 can be the second length L2.

[0068] The area of ​​adjacent portions ADJ of the connector can be obtained by multiplying the width of the first end ED1 in the first direction D1 by the second length L2. The width of the main body portion MBD relative to the second direction D2 can be the first length L1. When the width of the main body portion MBD in the first direction D1 is substantially constant, the value of the second length relative to the first length, L2 / L1, can be approximately 0.2.

[0069] Return to reference Figure 3 The positive electrode active material layer CML may include a first region AR1 on the adjacent portion ADJ of the terminal block. The region of the positive electrode active material layer CML other than the first region AR1 may be defined as a second region AR2. The area of ​​the first region AR1 may correspond to the area of ​​the adjacent portion ADJ of the terminal block, but may also differ from the area of ​​the adjacent portion ADJ of the terminal block.

[0070] In an example embodiment, the solid electrolyte content in the first region AR1 may be less than the solid electrolyte content in the second region AR2. Solid electrolyte content can refer to the weight ratio of solid electrolyte to the total weight of the first region AR1. The solid electrolyte content in the first region AR1 may be about 10 wt% or less. The solid electrolyte content in the second region AR2 may be about 10 wt% or more. The first region AR1 and the second region AR2 can be distinguished based on their solid electrolyte content.

[0071] For example, the solid electrolyte content in the first region AR1 can range from about 5 wt% to about 10 wt%. The solid electrolyte content in the second region AR2 can range from about 10 wt% to about 25 wt%.

[0072] In an example embodiment, the content of the positive electrode active material in the first region AR1 can be greater than the content of the positive electrode active material in the second region AR2. For example, the content of the positive electrode active material in the first region AR1 can be in the range of about 85 wt% to about 95 wt% or about 90 wt% to about 95 wt%. The content of the positive electrode active material in the second region AR2 can be in the range of about 70 wt% to about 85 wt%.

[0073] As described above, by including a smaller amount of solid electrolyte, the first region AR1 located on the adjacent portion ADJ of the terminal block can include a relatively large amount of positive electrode active material CAC. By including a higher amount of positive electrode active material CAC, the first region AR1 can reduce or prevent excessive consumption of positive electrode active material CAC in the region adjacent to the positive electrode terminal block CTB. That is, the positive electrode active material layer CML can reduce or prevent the excessive use of positive electrode active material CAC on the adjacent portion ADJ of the terminal block.

[0074] In an example embodiment, the area of ​​the first region AR1 can be in the range of approximately 10% to approximately 40% of the total area of ​​the positive electrode active material layer CML. This area can be calculated based on the cross-sectional area of ​​a two-dimensional plane parallel to the positive electrode current collector COL1. For example, the area of ​​the first region AR1 can refer to the plane formed by the first direction D1 and the second direction D2 (see...). Figure 1 and Figure 2The area of ​​).

[0075] When the area of ​​the first region AR1 is less than approximately 10% of the total area of ​​the positive electrode active material layer CML, the effect becomes insignificant, making it practically impossible to perform the aforementioned function. When the area of ​​the first region AR1 is greater than approximately 40% of the total area of ​​the positive electrode active material layer CML, the solid electrolyte content in the positive electrode active material layer CML decreases, leading to a decrease in the ionic conductivity of the positive electrode, thus degrading the overall performance of the positive electrode. By having an area within the aforementioned range, the first region AR1 can solve the above problems while possessing appropriate physical properties as a positive electrode active material layer.

[0076] In the example embodiment, refer to Figure 5 The content of solid electrolyte (SEP) in the positive electrode active material layer (CML) gradually increases from the first end ED1 to the second end ED2. Furthermore, the content of positive electrode active material (CAC) in the positive electrode active material layer (CML) gradually increases from the second end ED2 to the first end ED1. That is, the higher the current density in a given region based on the positive electrode terminal block (CTB), the lower the content of solid electrolyte (SEP) can be, and the higher the content of positive electrode active material (CAC) can be. As a result, irreversible changes mainly occurring in regions where the consumption of positive electrode active material (CAC) is significant can be reduced or suppressed.

[0077] Reference Figure 6 and Figure 7 According to exemplary embodiments of this disclosure, the positive electrode may include a multilayer positive electrode active material layer CML. For example, the positive electrode active material layer CML may include a first positive electrode active material layer CML1 on the positive electrode current collector COL1 and a second positive electrode active material layer CML2 on the first positive electrode active material layer CML1. The thickness of the first positive electrode active material layer and the thickness of the second positive electrode active material layer may be different from each other. For example, the thickness of the first positive electrode active material layer CML1 may be less than the thickness of the second positive electrode active material layer CML2.

[0078] In an example embodiment, the solid electrolyte content of the first positive electrode active material layer CML1 can be less than the solid electrolyte content of the second positive electrode active material layer CML2. Furthermore, the positive electrode active material content of the first positive electrode active material layer CML1 can be greater than the positive electrode active material content of the second positive electrode active material layer CML2. For example, the solid electrolyte content of the first positive electrode active material layer CML1 can be about 10 wt% or less.

[0079] Reference Figure 7The second positive electrode active material layer CML2 may include the first region AR1 described above. The first region AR1 may be vertically stacked with the adjacent portion ADJ of the terminal block. By setting the solid electrolyte content in the adjacent portion ADJ of the second positive electrode active material layer CML2 to a low level, excessive consumption of the positive electrode active material in the region adjacent to the positive electrode terminal block CTB can be reduced or prevented. For example, the second positive electrode active material layer CML2 may include a first region AR1 and a second region, wherein the solid electrolyte content of the first region AR1 is about 10 wt% or less, and the solid electrolyte content of the second region AR2 is about 10 wt% or more. The solid electrolyte content of the first region AR1 may be less than the solid electrolyte content of the second region AR2.

[0080] By including a relatively large amount of positive electrode active material, the first positive electrode active material layer CML1 can improve electronic conductivity and promote electron exchange with the positive electrode current collector COL1. Furthermore, by reducing the solid electrolyte content in the first region AR1 on the adjacent portion ADJ of the second positive electrode active material layer CML2, the content of the positive electrode active material CAC in the region adjacent to the positive electrode terminal CTB can be increased. Therefore, the structural arrangement of the positive electrode active material layers CML can provide overall electrochemical stability for the positive electrode.

[0081] As described above, the positive electrode CSH according to the exemplary embodiments of this disclosure can improve or optimize its performance by adjusting the regions and composition within the positive electrode active material layer CML. For example, by controlling the solid electrolyte content of the first region AR1 and the second region AR2, the positive electrode active material content of the first region AR1 and the second region AR2, and the area ratio of the first region AR1 and the second region AR2, an overall balance in the electrode can be achieved and its performance enhanced. Furthermore, the multilayer structure of the positive electrode active material layer allows for electrode designs that meet various requirements of all-solid-state batteries. Therefore, by improving the stability and cycle life performance of the positive electrode, a high-performance all-solid-state battery can be provided.

[0082] In the following text, refer to Figure 8 and Figure 9 Other components of an all-solid-state battery according to an example embodiment of this disclosure are described. Figure 8 and Figure 9 This is a cross-sectional view of a cell cell (CEL) according to a disclosed example embodiment.

[0083] The cell cell (CEL) may include a positive electrode (CSH), a negative electrode (ASH), and a solid electrolyte layer (SEL) between the positive electrode (CSH) and the negative electrode (ASH). The positive electrode (CSH) may include a positive electrode current collector (COL1) and a positive electrode active material layer (CML) on the positive electrode current collector (COL1). The negative electrode (ASH) may include a negative electrode current collector (COL2) and a negative electrode coating (AML) on the negative electrode current collector (COL2). The negative electrode current collector (COL2) may include a negative electrode terminal block (ATB) protruding in one direction. The negative electrode terminal block (ATB) may be oriented in the same direction as the positive electrode terminal block (CTB), or it may be oriented in the opposite direction.

[0084] The negative electrode ASH may include a negative electrode current collector COL2 and a negative electrode coating AML on the negative electrode current collector COL2. The negative electrode current collector COL2 may provide a reference surface on which the negative electrode coating AML is disposed. The negative electrode current collector COL2 may include, for example, a material that does not react with lithium (i.e., does not form an alloy or compound with lithium). For example, the negative electrode current collector COL2 may include at least one metal, such as or comprising 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 COL2 may range from about 1 μm to about 20 μm, for example from about 5 μm to about 15 μm and for example from about 7 μm to about 10 μm.

[0085] The negative electrode current collector COL2 may be composed of or include a single metal (such as or including at least one of the aforementioned metals), or may include an alloy or coating material comprising two or more metals. The negative electrode current collector COL2 may be in the form of, for example, a plate or foil. In some example embodiments, the negative electrode current collector COL2 may be omitted.

[0086] Although not shown, the negative electrode current collector COL2 according to an exemplary embodiment of this disclosure may include a substrate film and a metal layer disposed on one or both surfaces of the substrate film. The substrate film may include, for example, a polymer. The polymer may be, or include, for example, a thermoplastic polymer. The polymer may include at least one of, for example, polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polybutylene terephthalate (PBT), polyimide (PI), and combinations thereof. The polymer may be, or include, an insulating polymer. By including an insulating thermoplastic polymer, the substrate film can soften or liquefy in the event of a short circuit, thereby interrupting battery operation and reducing or suppressing a rapid increase in current. The metal layer may include, for example, at least one of copper (Cu), stainless steel, titanium (Ti), iron (Fe), cobalt (Co), nickel (Ni), and alloys thereof. The negative electrode current collector COL2 may also include a metal sheet and / or lead terminals. For further details regarding the substrate film, metal layer, metal sheet, and lead terminals of the negative electrode current collector COL2, refer to the positive electrode current collector COL1 described above. With this structure, the negative electrode current collector COL2 can reduce the weight of the negative electrode ASH, thus increasing the energy density of the cell CEL.

[0087] The negative electrode coating AML can be configured to allow lithium metal to grow between the cell cell CEL and the negative electrode current collector COL2 during charging. The negative electrode coating AML can serve as a protective layer for the lithium metal and reduce or suppress the deposition and growth of lithium dendrites.

[0088] The negative electrode coating AML can include metals and carbon. For example, the negative electrode coating AML can include at least one metal, such as or including at least one of gold (Au), platinum (Pt), palladium (Pd), silicon (Si), silver (Ag), aluminum (Al), bismuth (Bi), tin (Sn), and zinc (Zn). The metal in the negative electrode coating AML can help lithium ions move towards the negative electrode current collector COL2 during charging and discharging of the all-solid-state battery.

[0089] The negative electrode coating AML may include at least one of amorphous carbon, crystalline carbon, and porous carbon. The negative electrode coating AML may include at least one type of carbon, such as or including at least one of carbon black, acetylene black, furnace black, Ketjen black, and graphene. The carbon in the negative electrode coating AML can reduce or minimize the volume change of the all-solid-state battery during charging and discharging, and can provide structural stability to the negative electrode coating AML.

[0090] In an example embodiment, the negative electrode coating AML may include a mixture (or composite) of carbon black and silver (Ag).

[0091] The negative electrode coating AML can have a thickness smaller than that of the positive electrode active material layer CML. For example, the negative electrode coating AML can have a thickness equal to or less than about 50%, about 40%, about 30%, about 20%, about 10%, or about 5% of the thickness of the positive electrode active material layer CML. The thickness of the negative electrode coating AML can, for example, be in the range of about 1 μm to about 20 μm, about 2 μm to about 10 μm, or about 3 μm to about 7 μm. When the thickness of the negative electrode coating AML is too thin (e.g., less than about 1 μm), lithium dendrites formed between the negative electrode coating AML and the negative electrode current collector COL2 may penetrate the negative electrode coating AML and cause the negative electrode coating AML to collapse, thereby degrading the cycle characteristics of the cell CEL. On the other hand, when the thickness of the negative electrode coating AML is excessively increased (e.g., greater than about 20 μm), the energy density of the cell CEL may decrease, and the internal resistance of the cell CEL may increase due to the negative electrode coating AML, thereby degrading the cycle characteristics of the cell CEL.

[0092] In addition to metals and carbon, the negative electrode coating AML may also include other additives. The negative electrode coating AML may also include, for example, at least one additive, such as or including at least one of binders, fillers, coating agents, dispersants, and ionic conductive agents.

[0093] Although not shown, a carbon layer may also be included between the negative electrode coating AML and the solid electrolyte layer SEL to improve adhesion.

[0094] In another example embodiment, the negative electrode ASH of the cell CEL may further include a lithium metal layer (not shown) between the negative electrode current collector COL2 and the negative electrode coating AML. When the cell CEL is charged, the lithium metal layer may have an increased thickness. The negative electrode coating AML may constitute a protective layer for the lithium metal layer and may simultaneously or concurrently reduce or suppress the growth of lithium dendrites from the lithium metal layer.

[0095] The lithium metal layer may be or include a thin film of metal comprising lithium or a lithium alloy. The lithium alloy may include, but is not limited to, at least one of 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 may include at least one of these alloys or lithium. The lithium metal layer may include a variety of alloys.

[0096] A lithium metal layer can constitute the negative electrode active material layer. For example, in the negative electrode according to an exemplary embodiment of this disclosure, lithium or a lithium alloy can be used as the negative electrode active material. The negative electrode active material can form a lithium metal layer or can be dispersed within the negative electrode coating AML. The negative electrode active material can be present between the negative electrode current collector COL2 and the negative electrode coating AML.

[0097] A solid electrolyte layer (SEL) can be disposed between the positive electrode (CSH) and the negative electrode (ASH). The SEL can comprise a sulfide-based solid electrolyte with desired or improved lithium-ion conductivity. The solid electrolyte in the SEL can be the same as or different from any of the materials included in the solid electrolyte layer (SEP) in the aforementioned positive electrode active material layer (CML).

[0098] Solid electrolytes can have a particulate shape, such as spherical or elliptical. For example, the average particle size of solid electrolytes can be in the range of about 1 μm to about 20 μm, about 1 μm to about 15 μm, or about 3 μm to about 10 μm.

[0099] Solid electrolytes can include sulfide-based solid electrolytes. Solid electrolytes can be amorphous, crystalline, or mixtures thereof. Furthermore, solid electrolytes can include, for example, sulfur (S), phosphorus (P), and lithium (Li) as at least constituent elements in the aforementioned sulfide-based solid electrolyte materials. For example, a solid electrolyte can be or includes materials comprising Li₂S-P₂S₅. When the sulfide-based solid electrolyte material forming the solid electrolyte includes Li₂S-P₂S₅, the molar mixing ratio of Li₂S to P₂S₅ can be in the range of about 50:50 to about 90:10.

[0100] In an example embodiment, the solid electrolyte may include 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 solid electrolyte may include at least one of the following silver-germanium sulfide compounds: Li6PS5Cl, Li6PS5Br, and Li6PS5I.

[0101] In another example embodiment, the solid electrolyte may include Li 7-a-c M a PS 6-c X cA sulfide-germanium ore-type compound. X can be or include Cl, Br, or combinations thereof. M can be or include at least one of Na, K, Fe, Mg, Ca, Ag, Cu, Zr, Zn, or combinations thereof. Each of a and c can be a real number in the range of 0 to 2.

[0102] The density of the argyrogermanium sulfide solid electrolyte (SEP) can range from about 1.5 g / cc to about 2.0 g / cc. Because the SEP has a density of about 1.5 g / cc or greater, the internal resistance of the all-solid-state battery can be reduced, and it is possible to prevent or avoid penetration and short circuits of the solid electrolyte membrane due to lithium dendrite formation. The elastic modulus of the SEP can, for example, range from about 15 GPa to about 35 GPa.

[0103] The solid electrolyte layer (SEL) may also include an adhesive. The adhesive included in the solid electrolyte layer (SEL) may be, but is not limited to, at least one of, for example, styrene-butadiene rubber (SBR), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyethylene, etc. For example, the adhesive included in the solid electrolyte layer (SEL) may include at least one of styrene-butadiene rubber (SBR), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyethylene, and polyacrylate. The adhesive of the solid electrolyte layer (SEL) may be the same as or different from the adhesive included in the positive electrode active material layer (CML) or the adhesive included in the negative electrode coating (AML).

[0104] Methods for manufacturing all-solid-state batteries Hereinafter, a method for manufacturing an all-solid-state battery according to an exemplary embodiment of the present disclosure will be described. Manufacturing an all-solid-state battery may include manufacturing a positive electrode, a negative electrode, and a solid electrolyte layer, respectively. However, in this specification, a method for manufacturing the positive electrode will be described.

[0105] For example, in addition to the method for manufacturing a positive electrode for an all-solid-state battery according to the exemplary embodiments of this disclosure, conventional manufacturing processes commonly used in the industry can be applied to other manufacturing steps of all-solid-state batteries.

[0106] A method for manufacturing a positive electrode according to an example embodiment of the present disclosure may include: forming an active material region on a metal substrate; forming a positive electrode sheet by drying the active material region; and forming a positive electrode composite layer by dicing the positive electrode sheet.

[0107] Reference Figure 10 and Figure 11A metal substrate MST can be conveyed in a first direction D1, and an active material composition can be coated on the conveyed metal substrate MST. A portion of the metal substrate MST can be defined as the coated region CTA, while the remaining region can be defined as the uncoated region NCA. The uncoated region NCA can be formed at one end of the metal substrate MST in the width direction (i.e., the second direction) D2. For example, as... Figure 10 As shown, the metal substrate MST may include an uncoated region NCA defined at a first side edge WED1 relative to the second direction D2. In another example, the metal substrate MST may include an uncoated region NCA defined at a second side edge WED2 opposite to the first side edge WED1.

[0108] The active material region may be formed only in the coated region CTA. That is, the uncoated region NCA can be defined as the region in which the active material region is omitted. By retaining a portion of the metal substrate MST as the uncoated region NCA, the ease of electrode fabrication can be improved. For example, the uncoated region NCA can be cut to form the electrode tab of the positive electrode according to an exemplary embodiment of the present disclosure. The coated region CTA can be cut to form the body portion of the positive electrode according to an exemplary embodiment of the present disclosure.

[0109] By continuously coating an active material composition onto a metal substrate MST conveyed along a first direction D1, the efficiency of electrode production can be improved. Furthermore, by coating with active material compositions of different compositions, the composition of the positive electrode active material layer can be easily designed during manufacturing. In an example embodiment, a first active material composition SD1 and a second active material composition SD2 can be coated together on the metal substrate. In this case, the composition and structure of the positive electrode to be manufactured can be considered when forming the active material region. Moreover, by adjusting the coating area of ​​the positive electrode active material region with different compositions, electrode design can be further facilitated. By considering the structure and composition of the electrode from the stage of coating the active material region on the metal substrate MST, the productivity and yield of electrode manufacturing can be improved.

[0110] Reference Figure 11 The active material region may include a first active material region AMR1 and a second active material region AMR2. Each of the first active material region AMR1 and the second active material region AMR2 may include a positive electrode active material and a solid electrolyte. For example, the first active material region AMR1 and the second active material region AMR2 may be formed side by side on a metal substrate MST in the width direction D2. The compositions of the first active material region AMR1 and the second active material region AMR2 may be different from each other.

[0111] Each of the first active material region AMR1 and the second active material region AMR2 can be formed on a metal substrate MST with a constant or substantially constant width. For example, the metal substrate MST can be conveyed in a first direction D1, and as the metal substrate MST is conveyed, the first active material composition SD1 can be coated with a constant or substantially constant width to form the first active material region AMR1. The second active material region AMR2 can be coated side-by-side with the first active material region AMR1 in the width direction D2 of the metal substrate MST. Through such a continuous process, it is easier to mass-produce positive electrode active material layers having the structure according to the exemplary embodiments of this disclosure.

[0112] Therefore, the first active material region AMR1 can have a first width W1. The second active material region AMR2 can have a second width W2. The first width W1 and the second width W2 can be adjusted to suit the structure of the electrode to be manufactured. For example, the first width W1 can be smaller than the second width W2.

[0113] In an example embodiment, the solid electrolyte content of the first active material region AMR1 may be less than the solid electrolyte content of the second active material region AMR2. The solid electrolyte content of the first active material region AMR1 may be less than or equal to about 10 wt%, and the solid electrolyte content of the second active material region AMR2 may be greater than or equal to about 10 wt%. For example, the solid electrolyte content of the first active material region AMR1 may be in the range of about 5 wt% to about 10 wt%. The solid electrolyte content of the second active material region AMR2 may be in the range of about 10 wt% to about 25 wt%.

[0114] As described above, a metal substrate MST may include uncoated regions in which the active material regions are omitted. These uncoated regions may be formed on one or both sides of the metal substrate MST. In an example embodiment, refer to... Figure 11 The metal substrate MST may include a first uncoated region NCA1 formed on one side thereon. Therefore, a first active material region AMR1 may be adjacent to the first uncoated region NCA1 in the width direction D2. That is, the first uncoated region NCA1, the first active material region AMR1, and the second active material region AMR2 may be arranged side-by-side in the width direction D2 of the metal substrate MST. In some cases, the metal substrate MST may also include a second uncoated region formed on the side opposite to the first uncoated region NCA1. For example, the second active material region AMR2 may be adjacent to the second uncoated region in the width direction D2.

[0115] A positive electrode sheet (CST) can be formed by drying the active material region on the metal substrate (MST). By drying the active material region, it can be used as a positive electrode active material layer with suitable thickness and physical properties.

[0116] The formed positive electrode sheet (CST) can be cut to form a positive electrode composite layer (CCL). The positive electrode composite layer (CCL) formed by cutting the positive electrode sheet (CST) can be used as the positive electrode in an all-solid-state battery. By cutting the positive electrode sheet (CST) into appropriate or desired sizes and shapes, a positive electrode for an all-solid-state battery can be provided.

[0117] For example, refer to Figure 12 A cutting line CTT can be set to match the shape of the positive electrode to be manufactured, and the positive electrode sheet CST can be cut along the cutting line CTT. At this time, the size and shape of the cutting line CTT can be adjusted according to the required capacity, size or shape of the positive electrode.

[0118] Figure 13 A positive electrode composite layer CCL, formed by cutting a positive electrode sheet CST, is shown as an example embodiment. A portion of a first uncoated region NCA1 can be cut by cutting the positive electrode sheet CST. By cutting a portion of the first uncoated region NCA1, a positive electrode terminal CTB can be formed from the positive electrode composite layer CCL. That is, the positive electrode terminal CTB of the positive electrode composite layer CCL can be formed by cutting the first uncoated region NCA1. By cutting the positive electrode sheet CST, only a portion of the active material region can be separated. That is, the positive electrode composite layer CCL may include a first positive electrode active material layer CML1 formed by cutting a portion of the active material region.

[0119] In an example embodiment, the positive electrode composite layer CCL may include a first active material region AMR1 and a second active material region AMR2. For example, the positive electrode composite layer CCL may include a positive electrode active material layer CML1 formed by cutting the first active material region AMR1 and the second active material region AMR2. In this case, the area of ​​the first active material region AMR1 and the area of ​​the second active material region AMR2 may be different from each other. The appropriate composition and structure of the positive electrode active material layer CML1 can be designed by adjusting the area of ​​the first active material region AMR1 and the area of ​​the second active material region AMR2.

[0120] Refer again Figure 12The area of ​​the active material region can be adjusted by the size and shape of the cutting line CTT. While the final area ratio of the positive electrode composite layer CCL can be adjusted by changing the area of ​​each of the first active material region AMR1 and the second active material region AMR2 during the coating step, the final area ratio of the positive electrode composite layer CCL can also be adjusted by cutting the positive electrode sheet CST. For example, as shown... Figure 12 The cutting line CTT of the form shown can keep the width of the first active material region AMR1 in the second direction D2 constant before and after cutting, but reduce the width of the second active material region AMR2 in the second direction D2.

[0121] In the example embodiment, the area of ​​the first active material region AMR1 can be adjusted during the step of forming the first active material region on the metal substrate, and the area of ​​the second active material region AMR2 can be adjusted by cutting the positive electrode sheet CST. In the positive electrode sheet CST, the width W1 of the first active material region can be relatively smaller than the width W2 of the second active material region.

[0122] That is, the area ratio of the active material region can be calculated based on the width of the active material region. For example, refer to... Figure 13 The area ratio of the active material regions can be calculated as the width W1 of the first active material region AMR1 and the width W3 of the positive electrode active material layer CML1 in the second direction D2.

[0123] In an example embodiment, the area of ​​the first active material region AMR1 can be in the range of approximately 10% to approximately 40% of the total area of ​​the positive electrode active material layer. Specifically, by adjusting the area of ​​the first active material region AMR1, which has a low content of solid electrolyte, to the above range, the performance of the positive electrode to be manufactured can be improved. By setting the content of solid electrolyte in the region of the positive electrode active material layer CML1 adjacent to the positive electrode terminal CTB to be low, the content of the positive electrode active material can be relatively high. This allows for the replenishment of the lithium source in the region where the current density is increased through the positive electrode terminal CTB.

[0124] Although the foregoing has primarily described the formation of a single positive electrode active material layer on a metal substrate (MST), the method for manufacturing a positive electrode according to exemplary embodiments of this disclosure may also include forming a double-layer positive electrode active material layer.

[0125] In an example embodiment, the positive electrode composite layer (CCL) may include a first positive electrode active material layer on a metal substrate (MST) and a second positive electrode active material layer on the first positive electrode active material layer. The second positive electrode active material layer may include the aforementioned first and second active material regions.

[0126] The positive electrode composite layer (CCL) may include a first positive electrode active material layer and a second positive electrode active material layer on the first positive electrode active material layer, the second positive electrode active material layer including active material regions of different compositions. The second positive electrode active material layer on the first positive electrode active material layer may include the first active material region having a relatively low solid electrolyte content, thereby increasing the active material content in the region adjacent to the positive electrode terminal block (CTB).

[0127] As described above, the method for manufacturing a positive electrode according to exemplary embodiments of this disclosure can improve or optimize the design and performance of the positive electrode by adjusting the area and composition of the active material regions on the metal substrate and by cutting the active material regions. For example, it is possible to adjust the solid electrolyte content, the positive electrode active material content, and the area ratio of the first active material region and the second active material region, taking into account factors such as the current density of the positive electrode, to achieve overall electrode balance and improve performance. Furthermore, according to the method of this disclosure, by realizing a positive electrode active material layer with a single-layer or double-layer structure, it is possible to facilitate the design of a positive electrode that meets various requirements of all-solid-state batteries. As a result, the productivity and yield of the positive electrode can be improved, and a high-performance all-solid-state battery can be provided.

[0128] Figure 16 This is a flowchart illustrating a method for manufacturing a positive electrode for an all-solid-state battery according to an example embodiment. Figure 16 In this method 1600, operations 1610, 1620, and 1630 are included. Operation 1610 includes forming a first active material region and a second active material region arranged side-by-side in the width direction of a metal substrate on a metal substrate. For example, at least one of the first and second active material regions includes a positive electrode active material and a solid electrolyte. In another example, the content of the solid electrolyte in the first active material region is less than or equal to about 10 wt%. In yet another example, the content of the solid electrolyte in the second active material region is greater than or equal to about 10 wt%. The content of the solid electrolyte in the first active material region may be less than the content of the solid electrolyte in the second active material region. In yet another example, based on the total weight of the first active material region, the content of the solid electrolyte in the first active material region is in the range of about 5 wt% to about 10 wt%, and based on the total weight of the second active material region, the content of the solid electrolyte in the second active material region is in the range of about 10 wt% to about 25 wt%.

[0129] Operation 1620 includes forming a positive electrode sheet by drying a first active material region and a second active material region. For example, the positive electrode sheet includes a first uncoated region formed on one side of the positive electrode sheet. In another example, the first active material region is adjacent to the first uncoated region in the width direction. Operation 1630 includes forming a positive electrode composite layer by dicing the positive electrode sheet. For example, the positive electrode composite layer includes an electrode tab formed by dicing the first uncoated region and a first positive electrode active material layer including the first active material region and the second active material region. In another example, the area of ​​the first active material region of the first positive electrode active material layer is in the range of about 10% to about 40% of the total area of ​​the first positive electrode active material layer. In other examples, the content of positive electrode active material in the first active material region is greater than the content of positive electrode active material in the second active material region. In yet another example, the positive electrode composite layer further includes a second positive electrode active material layer between a metal substrate and the first positive electrode active material layer.

[0130] In another example, the method further includes forming a carbon coating on a metal substrate. For example, a first active material region and a second active material region are formed on the carbon coating.

[0131] The present disclosure is described in more detail below with reference to examples. However, these embodiments are intended to illustrate examples of the present disclosure, and the scope of the present disclosure is not limited to these examples.

[0132] Preparation of the positive electrode: Prepare LiNi with an average particle size of approximately 15 μm 0.94 Co 0.04 Mn 0.02 O2 particles were used as the positive electrode active material. Li6PS5Cl, a sulfide-germanium ore type crystal with an average particle size of approximately 2.5 μm, was prepared as the solid electrolyte. PVdF-HFP was prepared as the binder. Carbon black (CB) was prepared as the conductive material. A mixture of the above-mentioned positive electrode active material, solid electrolyte, conductive material, and binder was used as the positive electrode slurry composition.

[0133] Preparation Example 1: First Positive Electrode Composition A first positive electrode composition was prepared by mixing a positive electrode active material, a solid electrolyte, a conductive material, and a binder in a weight ratio of 91.5:7:0.5:1.

[0134] Preparation Example 2: Second Positive Electrode Composition A second positive electrode composition was prepared by mixing positive electrode active material, solid electrolyte, conductive material and binder in a weight ratio of 85:13.5:0.5:1.

[0135] The positive electrode is described in detail below with reference to examples and comparative examples. The positive electrode is prepared by the following steps: dry coating a first positive electrode composition and / or a second positive electrode composition onto a surface of a positive electrode current collector made of an aluminum foil with a carbon-coated surface, and pressing the first positive electrode composition and / or the second positive electrode composition at about 10 MPa and 130°C for 10 minutes.

[0136] Preparation of the negative electrode: Silver (Ag) particles were prepared as the metal particles, and carbon black (CB) was prepared as the carbon material. After mixing the carbon black and silver particles at a weight ratio of 3:1, 4g of the mixed powder was placed in a container, and 4g of a methylpyrrolidone (NMP) solution containing 7wt% polyvinylidene fluoride (PVDF) binder (KUREHA #9300) was added to prepare the mixed solution.

[0137] A slurry was prepared by gradually adding NMP to the mixed solution while stirring. The prepared slurry was applied to a stainless steel (SUS) sheet using a bar coater, dried in air at 80°C for 10 minutes, and then vacuum-dried at 40°C for 10 hours to prepare a laminate. The prepared laminate was then cold-rolled to planarize the surface, thereby preparing a negative electrode with a negative electrode coating / negative electrode current collector structure. At this point, the thickness of the negative electrode coating was approximately 15 μm, and the area of ​​the negative electrode current collector was the same as the area of ​​the negative electrode coating.

[0138] Preparation of solid electrolyte layer: A mixture was prepared by mixing 98.5 parts by weight of Li6PS5Cl solid electrolyte as a sulforaphite-type crystal and 1.5 parts by weight of acrylic binder. Octyl acetate was added to the prepared mixture while stirring to prepare a slurry. The prepared slurry was applied to a 15 μm thick nonwoven fabric placed on a 75 μm thick PET substrate using a bar coater and dried in air at 80 °C for 10 minutes to prepare a laminate. The prepared laminate was then vacuum dried at 80 °C for 2 hours to prepare the solid electrolyte layer.

[0139] Assembly of all-solid-state batteries: A solid electrolyte layer was placed on the negative electrode, and the positive electrode was also placed on the solid electrolyte layer. The prepared laminate was pressed at approximately 85°C and 500 MPa for 30 minutes. Through this pressing process, the solid electrolyte layer was sintered, and the battery characteristics were improved. The thickness of the sintered solid electrolyte layer was approximately 45 μm.

[0140] The pressed laminate is placed in a bag and vacuum-sealed to manufacture an all-solid-state battery. A portion of the positive electrode current collector and a portion of the negative electrode current collector are each led out to the outside of the sealed battery and used as the positive electrode terminal and negative electrode terminal, respectively.

[0141] Example Example 1 The first positive electrode composition of Preparation Example 1 and the second positive electrode composition of Preparation Example 2 were coated side by side on a carbon-coated positive electrode current collector to form a positive electrode active material layer.

[0142] Specifically, a first positive electrode composition is coated onto the adjacent portions of the terminals of the main body, and a second positive electrode composition is coated side-by-side in the width direction. In this case, the width direction is based on the direction in which the positive electrode terminals protrude. That is, the first positive electrode composition and the second positive electrode composition are coated sequentially in the order adjacent to the positive electrode terminals.

[0143] The positive electrode is prepared in such a manner that the area of ​​the first region coated with the first positive electrode composition is about 15% relative to the total area of ​​the positive electrode active material layer, while the remaining second region coated with the second positive electrode composition has an area of ​​about 85%.

[0144] Example 2 The positive electrode was prepared with the same composition as in Example 1, except that the area of ​​the first region was about 35% and the area of ​​the second region was about 65% relative to the total area of ​​the positive electrode active material layer.

[0145] Example 3 A first positive electrode active material layer is formed on the carbon-coated positive electrode current collector, and a second positive electrode active material layer is further formed on the first positive electrode active material layer.

[0146] Specifically, a first positive electrode active material layer is formed by coating the first positive electrode composition of Preparation Example 1. A second positive electrode active material layer is formed on the first positive electrode active material layer, and the second positive electrode active material layer includes a first region and another second region on adjacent portions of the terminal block. In this case, the first region is formed by coating the first positive electrode composition of Preparation Example 1, and the second region is formed by coating the second positive electrode composition of Preparation Example 2.

[0147] The positive electrode is prepared in such a manner that the area of ​​the first region is approximately 15% relative to the total area of ​​the second positive electrode active material layer, while the area of ​​the second region is approximately 85%.

[0148] Comparison Example 1 The first positive electrode composition of Preparation Example 1 was coated onto a carbon-coated positive electrode current collector to form a positive electrode active material layer.

[0149] Comparison Example 2 The second positive electrode composition of Preparation Example 2 was coated onto a carbon-coated positive electrode current collector to form a positive electrode active material layer.

[0150] Compare Example 3 The positive electrode was prepared using the same composition as in Example 1, except that the area of ​​the first region was about 5% and the area of ​​the second region was about 95% relative to the total area of ​​the positive electrode active material layer.

[0151] Compare Example 4 The positive electrode was prepared using the same composition as in Example 1, except that the area of ​​the first region was approximately 50% of the total area of ​​the positive electrode active material layer, while the area of ​​the second region was approximately 50%.

[0152] As described above, all-solid-state batteries are manufactured in the same manner, except for changing the positive electrode. All-solid-state batteries based on the examples and comparative examples are summarized in Table 1 below.

[0153] In Examples 1 and 2, the positive electrode active material layer comprises a single layer and has a structure in which a first region and another second region on adjacent portions of the terminals are separated to have different compositions. In Example 3, a double-layer positive electrode active material layer is included, and the second positive electrode active material layer is divided into a first region and another second region on adjacent portions of the terminals.

[0154] In Comparative Examples 1 and 2, a monolayer is formed, and the regions are not separated. In Comparative Examples 3 and 4, the positive electrode active material layer is a monolayer, but it is divided into two regions with different compositions.

[0155] Table 1:

[0156] Evaluation Example 1: Battery Performance Evaluation The performance of the all-solid-state battery was evaluated based on the examples and comparative examples above. For example, the first cycle involved charging at a constant current of 0.05C for 20 hours until the battery voltage reached 4.2V. Then, it was discharged at a current of 0.05C for 20 hours until the battery voltage reached 3.0V.

[0157] The second cycle involves charging the battery at a constant current of 0.1C for 10 hours until the battery voltage reaches 4.2V. Then, the battery is discharged at a constant current of 0.1C for 10 hours until the battery voltage reaches 3.0V.

[0158] After the second cycle, charge and discharge were performed under the same conditions as the second cycle until 100 cycles were completed. Capacity retention was evaluated as shown in Equation 1 below.

[0159] Formula 1: Capacity retention rate (%) = [Discharge capacity in the nth cycle / Discharge capacity in the 1st cycle] × 100.

[0160] The capacity retention rates after 100 cycles are shown in Table 2 below. However, the evaluation was terminated at an early stage when the capacity retention rate was less than 80%.

[0161] Table 2:

[0162] Referring to the evaluation results above, it can be seen that the all-solid-state battery in the example exhibits a relatively high capacity retention rate. This indicates that the positive electrode of the example embodiment according to this disclosure has a region containing less solid electrolyte on the adjacent portion of the terminals, thereby improving or optimizing the electro / chemical balance of the positive electrode, and consequently, improving lifetime characteristics.

[0163] In the case of Comparative Example 1, the overall reduction in the solid electrolyte content in the positive electrode active material layer leads to a decrease in performance. This is presumably because, in all-solid-state batteries, a low solid electrolyte content hinders the smooth movement of lithium ions, reducing or preventing the electrode from exhibiting the desired performance.

[0164] In the case of comparison example 3, the first region is formed too small, indicating that its effect is not very significant.

[0165] Conversely, in comparative example 4 where the first region is too large, the total solid electrolyte content in the positive electrode decreases, leading to reduced performance.

[0166] Evaluation Example 2: Interface Analysis of All-Solid-State Batteries In the all-solid-state battery according to the above examples and comparative examples, the cross-section of the positive electrode active material layer after the charge / discharge process is analyzed. Figure 14A It is an image of the appearance of Example 1, and Figure 14B The image is an SEM image obtained by analyzing the cross-section of Example 1. Figure 15A This is an image comparing the appearance of Example 3. Figure 15B The SEM images were obtained by analyzing and comparing the profiles at the anomalous deposition sites in Example 3.

[0167] The superiority of the examples disclosed herein was confirmed by a comparative analysis of the initial appearance and the appearance after 100 cycles. Unlike the comparative examples, it was found that the positive electrode active material layer remained stable even after numerous charge / discharge processes.

[0168] For example, refer to Figure 15A The appearance of the all-solid-state battery confirmed abnormal precipitation at the upper end. This indicates that the precipitation mainly occurred in the area adjacent to the terminals. Figure 15B yes Figure 15A SEM image of the precipitated region profile. (Refer to...) Figure 15B As can be seen, unlike the example, the positive electrode in the comparative example does not retain its structure.

[0169] According to exemplary embodiments of this disclosure, by improving the uniformity of the electrodes, localized irreversible deposition and short circuits can be reduced or prevented. As a result, the stability and lifespan of the battery can be improved.

[0170] While this disclosure has been described with reference to exemplary embodiments, it should be understood that these exemplary embodiments are provided for illustrative purposes only and do not limit the scope of this disclosure. Various modifications and equivalent arrangements may be made without departing from the spirit and scope of the appended claims. Therefore, the described examples should be considered as examples and not as limitations on this disclosure.

Claims

1. A positive electrode for an all-solid-state battery, the positive electrode comprising: Positive electrode current collector; as well as The positive electrode active material layer is located on the positive electrode current collector. The positive electrode current collector includes a main body and a positive electrode terminal piece protruding from the main body in one direction. The positive electrode active material layer is disposed on the main body and includes the positive electrode active material and a solid electrolyte. The main body includes a first end and a second end that are opposite to each other in one direction. The first end portion spans the boundary between the positive electrode terminal and the main body. The main body includes adjacent portions of a connector extending from the first end to the second end. The positive electrode active material layer includes a first region and a second region. The first region is located on the adjacent portion of the terminal block, and the second region is the remaining portion excluding the first region. Wherein, the content of solid electrolyte in the first region is less than or equal to 10 wt%, and The content of solid electrolyte in the second region is greater than or equal to 10 wt%.

2. The positive electrode according to claim 1, wherein, The adjacent portion of the connector is defined as an area having 20% ​​of the total area of ​​the main body portion.

3. The positive electrode according to claim 1, wherein, The first region has an area ranging from 10% to 40% of the total area of ​​the positive electrode active material layer.

4. The positive electrode according to claim 1, wherein, Based on the total weight of the first region, the content of solid electrolyte in the first region is in the range of 5 wt% to 10 wt%.

5. The positive electrode according to claim 1, wherein, Based on the total weight of the second region, the content of solid electrolyte in the second region is in the range of 10 wt% to 25 wt%.

6. The positive electrode according to claim 1, wherein, The positive electrode active material layer includes a first positive electrode active material layer on the positive electrode current collector and a second positive electrode active material layer on the first positive electrode active material layer, and The second positive electrode active material layer includes the first region and the second region.

7. The positive electrode according to claim 6, wherein, The thickness of the first positive electrode active material layer is less than the thickness of the second positive electrode active material layer, and The content of solid electrolyte in the first positive electrode active material layer is less than or equal to 10 wt%.

8. The positive electrode according to claim 1, wherein, The content of the positive electrode active material in the first region is greater than the content of the positive electrode active material in the second region.

9. The positive electrode according to claim 1, wherein, The content of solid electrolyte in the positive electrode active material layer gradually increases from the first end to the second end.

10. The positive electrode according to claim 1, in, Solid electrolytes include those made of Li 7-a-c M a PS 6-c X c The term represents a sulfide solid electrolyte of the sulfide type, where 0 ≤ a ≤ 2 and 0 ≤ c ≤ 2. Wherein, X includes at least one of F, Br, Cl, and combinations thereof, and M includes at least one of scandium, yttrium, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, technetium, rhenium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, cadmium, mercury, aluminum, gallium, indium, thallium, silicon, germanium, tin, lead, arsenic, antimony, bismuth, and combinations thereof.

11. The positive electrode according to claim 1, wherein the positive electrode further comprises a carbon coating between the positive electrode current collector and the positive electrode active material layer.

12. An all-solid-state battery, the all-solid-state battery comprising: The positive electrode according to claim 1; The negative electrode includes a negative electrode current collector and a negative electrode coating on the negative electrode current collector; 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 negative electrode coating comprises carbon materials and metal particles. The metal particles include at least one selected from gold, platinum, palladium, silicon, silver, aluminum, bismuth, tin, and zinc. The carbon-based materials include at least one of amorphous carbon, crystalline carbon, and porous carbon.

14. The all-solid-state battery according to claim 12, further comprising a lithium metal layer between the negative electrode current collector and the negative electrode coating. in, The lithium metal layer comprises lithium metal or an alloy of lithium metal.

15. A method for manufacturing a positive electrode for an all-solid-state battery, the method comprising the steps of: A first active material region and a second active material region are formed side by side in the width direction of the metal substrate, wherein at least one of the first active material region and the second active material region includes a positive electrode active material and a solid electrolyte. A positive electrode sheet is formed by drying the first active material region and the second active material region; and A positive electrode composite layer is formed by cutting the positive electrode sheet. The positive electrode sheet includes a first uncoated region formed on one side of the positive electrode sheet. Wherein, the first active material region is adjacent to the first uncoated region in the width direction. The positive electrode composite layer includes an electrode tab formed by cutting the first uncoated area and a first positive electrode active material layer including the first active material region and the second active material region. Wherein, the content of solid electrolyte in the first active material region is less than or equal to 10 wt%, and The content of solid electrolyte in the second active material region is greater than or equal to 10 wt%.

16. The method according to claim 15, wherein, The first active material region of the first positive electrode active material layer has an area ranging from 10% to 40% of the total area of ​​the first positive electrode active material layer.

17. The method according to claim 15, wherein, Based on the total weight of the first active material region, the content of solid electrolyte in the first active material region is in the range of 5 wt% to 10 wt%, and Wherein, based on the total weight of the second active material region, the content of solid electrolyte in the second active material region is in the range of 10wt% to 25wt%.

18. The method according to claim 15, wherein, The content of positive electrode active material in the first active material region is greater than the content of positive electrode active material in the second active material region.

19. The method of claim 15, further comprising forming a carbon coating on the metal substrate, in, The first active material region and the second active material region are formed on the carbon coating.

20. The method of claim 15, wherein, The positive electrode composite layer further includes a second positive electrode active material layer located between the metal substrate and the first positive electrode active material layer.

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