battery

Abstract

This invention relates to batteries. The invention discloses the following technology: in batteries using sulfide-based positive electrode active materials, even when the volume of the sulfide-based positive electrode active material changes due to charging and discharging, it is possible to suppress the peeling of the positive electrode current collector from the positive electrode active material layer. The battery of this invention comprises a positive electrode current collector, a positive electrode active material layer, an electrolyte layer, and a negative electrode. The positive electrode active material layer contains a sulfide-based active material. The positive electrode current collector has a contact surface that contacts the positive electrode active material layer. The arithmetic mean roughness of the contact surface is 0.25 μm or more.

Description

Technical Field

[0001] This application discloses a battery. Background Technology

[0002] Patent document 1 discloses a battery using a sulfur-based positive electrode active material.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2022-158610 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] Batteries using sulfur-based positive electrode active materials are prone to separation of the positive electrode current collector from the positive electrode active material layer due to the volume change of the sulfur-based positive electrode active material during charging and discharging.

[0008] Methods for solving problems

[0009] As a method for solving the above problems, this application discloses the following multiple methods.

[0010] <Method 1>

[0011] A battery comprising a positive current collector, a positive active material layer, an electrolyte layer, and a negative electrode, wherein the positive active material layer comprises a sulfur-based active material, the positive current collector has a contact surface that contacts the positive active material layer, and the arithmetic mean roughness of the contact surface is 0.25 μm or more.

[0012] <Method 2>

[0013] According to the battery of method 1, the positive current collector mentioned above contains Al.

[0014] <Method 3>

[0015] According to method 1 or 2, the arithmetic mean roughness of the aforementioned contact surface is 0.32 μm or more.

[0016] <Method 4>

[0017] According to any one of methods 1 to 3, the arithmetic mean roughness of the contact surface is less than 0.57 μm.

[0018] <Method 5>

[0019] According to any one of methods 1 to 4, the arithmetic mean roughness of the contact surface is greater than 0.32 μm and less than 0.57 μm.

[0020] <Method 6>

[0021] According to any one of methods 1 to 5, the positive electrode active material layer contains P-containing sulfide and carbon.

[0022] <Method 7>

[0023] According to any one of methods 1 to 6, the electrolyte layer comprises a solid electrolyte.

[0024] <Method 8>

[0025] According to any one of the methods 1 to 7, the negative electrode is accompanied by the deposition of metallic lithium during charging and the dissolution of metallic lithium during discharging.

[0026] Invention Effects

[0027] According to the technology of the present invention, in a battery using a sulfur-based positive electrode active material, even when the volume of the sulfur-based positive electrode active material changes due to charging and discharging, the positive electrode current collector and the positive electrode active material layer are not easily separated. Attached Figure Description

[0028] Figure 1 This is a simplified illustration of an example of battery construction.

[0029] Figure 2 This is a SEM image showing the interface between the positive electrode active material layer and the positive electrode current collector in a cross-section of the battery cell of Example 2. Detailed Implementation

[0030] Hereinafter, one embodiment of the battery of the present invention will be described, but the battery of the present invention is not limited to the embodiment described below.

[0031] 1. Battery

[0032] like Figure 1 As shown, a battery 100 according to one embodiment includes a positive current collector 10, a positive active material layer 20, an electrolyte layer 30, and a negative electrode 40. The positive active material layer 20 contains a sulfur-based active material. The positive current collector 10 has a contact surface 11 that contacts the positive active material layer 20. The arithmetic mean roughness of the contact surface 11 is 0.25 μm or more.

[0033] 1.1 Positive current collector

[0034] like Figure 1As shown, the battery 100 includes a positive current collector 10. The positive current collector 10 has a contact surface 11 that contacts the positive active material layer 20. The positive current collector 10 is not particularly limited in its shape (material, shape, size, etc.) as long as the arithmetic mean roughness of the contact surface 11 is 0.25 μm or more. The positive current collector 10 can be, for example, foil or plate. The positive current collector 10 can be a metal foil. Alternatively, the positive current collector 10 may have a layer formed of a resin composition comprising a resin and a conductive material. Alternatively, the positive current collector 10 may comprise a combination of a metal foil and a layer formed of a resin composition. The positive current collector 10 can be composed of two or more foils or sheets. The metal constituting the metal foil serving as the positive current collector 10 can be selected from at least one of Cu, Ni, Cr, Au, Pt, Ag, Al, Fe, Ti, Zn, Co, V, Mg, Pb, Ge, In, Sn, Zr, and stainless steel. Particularly from the viewpoint of ensuring oxidation resistance, the positive current collector 10 may contain Al. As will be described later, when the positive current collector 10 contains Al, the surface of the positive current collector 10 can be chemically dissolved, its surface roughness can be precisely controlled, and it also has the advantage of easily controlling the arithmetic mean roughness of the contact surface 11 within a specified range. The positive current collector 10 can be a positive current collector on which the aforementioned metal is plated or vapor-deposited onto a metal foil or substrate. Furthermore, when the positive current collector 10 is composed of two or more metal foils, a certain layer can be formed between the two or more metal foils. The thickness of the positive current collector 10 is not particularly limited. The thickness of the positive current collector 10 can, for example, be 1 μm or more and 1 mm or less.

[0035] The contact surface 11 of the positive current collector 10 has an arithmetic mean roughness of 0.25 μm or more. With such an arithmetic mean roughness, even if the contact surface 11 is tightly bonded to the positive electrode active material layer 20 and the volume of the sulfide active material changes with charging and discharging, the positive current collector 10 is difficult to peel off from the positive electrode active material layer 20. Furthermore, with such an arithmetic mean roughness, the short-circuit withstand capacity of the battery is easily increased. The sulfide active material is flexible, so even if the size (particle size) of the sulfide active material is large, it can be deformed along the unevenness of the contact surface 11 of the positive current collector 10. According to the inventors, regardless of the size of the sulfide active material, by making the arithmetic mean roughness of the contact surface 11 0.25 μm or more, sufficient adhesion between the contact surface 11 and the positive electrode active material layer 20 can be ensured. In particular, when the arithmetic mean roughness of the contact surface 11 is 0.32 μm or more, the peel strength between the contact surface 11 and the positive electrode active material layer 20 is easily further improved. On the other hand, when the arithmetic mean roughness of the contact surface 11 is too large, the unevenness of the contact surface 11 becomes excessive, and sometimes the convex portion of the contact surface 11 breaks (front-end breakage) due to contact with the positive electrode active material layer 20 and the volume change of the positive electrode active material layer 20. Although the peel strength between the positive electrode current collector 10 and the positive electrode active material layer 20 is increased when the unevenness of the contact surface 11 is too large compared with the peel strength when the contact surface 11 is a smooth surface, the increase is smaller. In addition, excessively increasing the arithmetic mean roughness of the contact surface 11 can easily lead to a decrease in the mechanical strength of the positive electrode current collector 10, and can also easily lead to an increase in the manufacturing cost of the positive electrode current collector 10. According to the inventors' understanding, when the arithmetic mean roughness of the contact surface 11 is 0.57 μm or less, specifically when the arithmetic mean roughness of the contact surface 11 is greater than 0.32 μm and less than 0.57 μm, the peel strength between the positive current collector 10 and the positive active material layer 20 can be further improved, and the short-circuit withstand capacity of the battery can be further increased. The arithmetic mean roughness of the contact surface 11 can be 0.35 μm or more and 0.55 μm or less, 0.37 μm or more and 0.53 μm or less, or 0.40 μm or more and 0.50 μm or less.

[0036] The arithmetic mean roughness of the contact surface 11 of the positive current collector 10 can be adjusted by roughening a portion of the surface of the positive current collector 10 that forms the contact surface 11. Examples of roughening treatments include chemical dissolution (etching, etc.), machining, plating, and laser processing. For instance, when the positive current collector 10 contains Al, a portion of the surface of the positive current collector 10 can be easily chemically dissolved, and by precisely controlling the surface roughness through dissolution time, the arithmetic mean roughness of the contact surface 11 can be easily controlled within a specified range. The shape of the contact surface 11 is not particularly limited. In one embodiment, the contact surface 11 of the positive current collector 10 can be porous.

[0037] The arithmetic mean roughness of the contact surface 11 of the positive current collector 10 remains substantially unchanged before the positive active material layer 20 is formed on the surface of the positive current collector 10 and after it is assembled into the battery 100 as a positive electrode. In this regard, for example, by removing the positive current collector 10 from the battery 100 and examining the surface on the side of the positive active material layer 20 on the surface of the positive current collector 10, the arithmetic mean roughness of the contact surface 11 of the positive current collector 10 can be measured. The arithmetic mean roughness of the contact surface 11 of the positive current collector 10 is measured as follows: the positive electrode is removed from the battery, the positive active material is peeled off from the positive current collector, and the positive composite material is removed from the surface of the positive current collector, exposing the contact surface of the positive current collector. For the exposed contact surface, a non-contact surface roughness meter (e.g., Keyence VK-X3000 laser microscope) was used to measure the arithmetic mean roughness of any 10 locations within the 2067μm×2757μm measurement range, based on JIS B 0601:2013. The average value of this roughness was taken as "arithmetic mean roughness of the exposed surface of the positive current collector".

[0038] 1.2 Positive Electrode Active Material Layer

[0039] like Figure 1 As shown, the battery 100 includes a positive electrode active material layer 20 that contacts a contact surface 11, which is at least a portion of the surface of the positive electrode current collector 10. The positive electrode active material layer 20 comprises a sulfide-based active material. In addition to the sulfide-based active material, the positive electrode active material layer 20 may also contain one or more of other active materials, electrolytes, conductive materials, and binders. In one embodiment, the positive electrode active material layer 20 may comprise a sulfide-based active material, a phosphorus-containing sulfide, and carbon. By including a phosphorus-containing sulfide in the positive electrode active material layer 20, the ionic conductivity of the positive electrode active material layer 20 is easily improved. That is, the phosphorus-containing sulfide can function as an electrolyte. Furthermore, by including carbon in the positive electrode active material layer 20, the electronic conductivity of the positive electrode active material layer 20 is easily improved. That is, carbon can function as a conductive material.

[0040] 1.2.1 Sulfide-based active substances

[0041] The sulfur-based active material only needs to react with Li ions (which act as charge-compensating ions) during discharge to form a compound containing sulfur and lithium (such as sulfides like Li₂S) as a discharge product, and be able to release Li ions during charging. The sulfur-based active material can contain elemental sulfur or be composed entirely of elemental sulfur. Elemental sulfur can be octasulfide (S₈) or any other elemental sulfur. Octasulfide (S₈) can be α-sulfur, β-sulfur, γ-sulfur, or a combination thereof. The sulfur-based active material contained in the positive electrode active material layer 20 can be dissolved in P-containing sulfides (described later) or chemically bonded to P-containing sulfides. For example, the S in the sulfur-based active material can chemically bond with the S in the P-containing sulfides. The shape of the sulfur-based active material contained in the positive electrode active material layer 20 is not particularly limited; for example, it can be in particle form. As described above, in this embodiment, regardless of the size of the sulfur-based active material, by ensuring that the arithmetic mean roughness of the contact surface 11 of the positive electrode current collector 10 is 0.25 μm or more, sufficient adhesion between the contact surface 11 and the positive electrode active material layer 20 can be guaranteed. Whether the positive electrode active material layer 20 contains sulfur-based active materials can be determined by performing various analyses such as XAFS, XRD, and NMR on the composite material constituting the positive electrode active material layer 20. For example, when the positive electrode active material layer 20 is composed of a composite material containing elemental sulfur, when an X-ray diffraction pattern is obtained for the composite material using CuKα as the X-ray source, diffraction peaks originating from elemental sulfur are confirmed in the X-ray diffraction pattern. Diffraction peaks originating from elemental sulfur typically appear at 2θ = 23.05° ± 0.50°, 25.84° ± 0.50°, and 27.70° ± 0.50°. The amount of sulfur-based active material contained in the positive electrode active material layer 20 is not particularly limited, and can be appropriately determined according to the target battery performance. In one embodiment, the content of sulfur-based active material in the positive electrode active material layer 20 can be 10% by mass or more and 100% by mass or less, 20% by mass or more and 80% by mass or less, or 30% by mass or more and 60% by mass or less.

[0042] 1.2.2 P-containing sulfides

[0043] The P-containing sulfide contains at least P and S as constituent elements, and may further contain other elements M. Examples of other elements M include one or more of Ge, Sn, Si, B, and Al. In addition to P, S, and optional element M as constituent elements, the P-containing sulfide may or may not contain Li. As described above, the P-containing sulfide can function as an electrolyte in the positive electrode active material layer 20, improving the Li-ion conductivity of the positive electrode active material layer 20. The P-containing sulfide may have a positive structure of P (PS4 structure). Furthermore, the P-containing sulfide may contain sulfides that are compounds of P and S (e.g., P2S5). The shape of the P-containing sulfide contained in the positive electrode active material layer 20 is not particularly limited; for example, it may be particle-like. Whether the positive electrode active material layer 20 contains P-containing sulfides can be determined by performing various analyses such as XAFS, XRD, and NMR on the composite material constituting the positive electrode active material layer 20. For example, when the positive electrode active material layer 20 is composed of a composite material containing P2S5, when an X-ray diffraction pattern is obtained for this composite material using CuKα as the X-ray source, diffraction peaks originating from P2S5 are identified in the X-ray diffraction pattern. Typical P2S5 diffraction peaks appear at 2θ = 25.84° ± 0.50°, 30.35° ± 0.50°, and 31.32° ± 0.50°. Furthermore, when the composite material is measured using XAFS, peaks originating from P2S5 are identified. Additionally, when the P-containing sulfide contained in the composite material has a positive structure (PS4 structure), peaks originating from the positive structure are identified when the composite material is measured using XAFS. The amount of P-containing sulfide contained in the positive electrode active material layer 20 is not particularly limited and can be appropriately determined according to the target battery performance. In one embodiment, the content of P-containing sulfides in the positive electrode active material layer 20 can be 0% or more by mass and 90% or less by mass, 20% or more by mass and 80% or less by mass, or 30% or more by mass and 60% or less by mass. Furthermore, the molar ratio (P / S) of P to S in the positive electrode active material layer 20 is not particularly limited, and can be, for example, 0.03 or more by mass and 0.50 or less. Here, the denominator of the molar ratio (P / S) refers to the total amount of S contained in the positive electrode active material layer 20. When the positive electrode active material layer 20 contains sulfur-based active materials, P-containing sulfides, and other sulfides described later, all of which contain S, the total amount of these S elements is used as the denominator of the molar ratio (P / S).

[0044] 1.2.3 Carbon

[0045] Carbon may be elemental carbon, for example. Carbon can be one or more of carbon nanotubes, vapor-grown carbon fibers (VGCF), acetylene black, furnace black, Ketjen black, activated carbon, and graphene. Especially when the positive electrode active material layer 20 contains carbon nanotubes, high performance is easily ensured as a battery. The amount of carbon contained in the positive electrode active material layer 20 is not particularly limited and can be appropriately determined according to the target battery performance. In one embodiment, the carbon content in the positive electrode active material layer 20 can be 0% by mass or more and 50% by mass or less, 5% by mass or more and 40% by mass or less, or 10% by mass or more and 30% by mass or less.

[0046] 1.2.4 Other components

[0047] In addition to the components mentioned above, the positive electrode active material layer 20 may optionally contain other active materials, other sulfides, other conductive materials, and binders. The content of other components in the positive electrode active material layer 20 is not particularly limited.

[0048] Other active materials can be various lithium-containing compounds. These lithium-containing compounds can be lithium cobalt oxide, lithium nickel oxide, Li... 1±α Ni 1 / 3 Co 1 / 3 Mn 1 / 3 O 2±δ Lithium manganese oxide, spinel-based lithium compounds (Li 1+x Mn 2-x-y M y Various lithium oxides, such as lithium titanate and lithium metal phosphate (LiMPO4, etc., where M is selected from one or more of Al, Mg, Co, Fe, Ni and Zn), are used. It should be noted that the higher the proportion of sulfide active material in the overall positive electrode active material, the easier it is for the positive electrode active material layer 20 to expand and contract during charging and discharging, and the easier it is for the positive electrode current collector 10 to peel off from the positive electrode active material layer 20. However, according to this embodiment, as described above, by adjusting the arithmetic mean roughness of the contact surface 11 of the positive electrode current collector 10, such peeling is difficult to occur.

[0049] Other sulfides may contain at least element M (M being one or more of Ge, Sn, Si, B, and Al) and S as constituent elements. Other sulfides may also contain a normal structure of element M. Examples of normal structures of element M include one or more of GeS4, SnS4, SiS4, BS3, and AlS3 structures. Additionally, other sulfides may contain sulfides that are compounds of elements M and S (M... x S yHere, x and y are integers assigned electrical neutrality to S according to the kind of M. As M x S y For example, one or more of GeS2, SnS2, SiS2, B2S3 and Al2S3 can be listed.

[0050] Other conductive materials may include one or more conductive materials composed of various metallic materials. In one embodiment, the positive electrode active material layer 20 may also not contain conductive materials other than carbon.

[0051] The adhesive may be one or more selected from butadiene rubber (BR) based adhesives, butene rubber (IIR) based adhesives, acrylate butadiene rubber (ABR) based adhesives, styrene butadiene rubber (SBR) based adhesives, polyvinylidene fluoride (PVdF) based adhesives, polytetrafluoroethylene (PTFE) based adhesives, and polyimide (PI) based adhesives.

[0052] 1.3 Electrolyte layer

[0053] like Figure 1 As shown, the electrolyte layer 30 is disposed between the positive electrode active material layer 20 and the negative electrode 40. The electrolyte layer 30 contains at least an electrolyte. The electrolyte layer 30 may contain at least one of a solid electrolyte and a liquid electrolyte (electrolyte), and may optionally further contain a binder, etc. In particular, when the electrolyte layer 30 contains a solid electrolyte, it is easy to ensure higher performance. The electrolyte layer 30 may be a solid electrolyte layer without liquid electrolyte. According to the technology of the present invention, it is also less likely to cause the solid electrolyte layer to crack during the charging and discharging of the battery. Alternatively, the electrolyte layer 30 may also have a separator, etc., for holding the liquid electrolyte and preventing contact between the positive electrode active material layer 20 and the negative electrode 40. The thickness of the electrolyte layer 30 is not particularly limited, for example, it may be 0.1 μm or more or 1 μm or more, or 2 mm or less or 1 mm or less. The electrolyte layer 30 may be composed of one layer or two or more layers. For example, the electrolyte layer 30 may have a first layer disposed on the positive electrode active material layer 20 side and a second layer disposed on the negative electrode 40 side, or the first layer may contain a first electrolyte and the second layer may contain a second electrolyte. The first electrolyte and the second electrolyte can be different types of each other. The first electrolyte and the second electrolyte can each be at least one selected from oxide solid electrolytes, sulfide solid electrolytes, and ion-bound solid electrolytes, as described below. For example, the first layer may contain at least one of ion-bound solid electrolytes, and the second layer may contain at least one of ion-bound solid electrolytes and sulfide solid electrolytes.

[0054] 1.3.1 Solid Electrolytes

[0055] Solid electrolytes can be inorganic solid electrolytes or organic polymer electrolytes. In particular, inorganic solid electrolytes exhibit excellent ionic conductivity and heat resistance. Examples of inorganic solid electrolytes include oxide solid electrolytes, sulfide solid electrolytes, and ion-bound inorganic solid electrolytes. Among inorganic solid electrolytes, sulfide solid electrolytes, and especially those containing at least Li, S, and P as constituent elements, exhibit high performance. Alternatively, among inorganic solid electrolytes, ion-bound solid electrolytes, and especially those containing at least Li, Y, and a halogen (at least one of Cl, Br, I, and F) as constituent elements, exhibit high performance. Solid electrolytes can be amorphous or crystalline. Solid electrolytes can be in particulate form. The average particle size (D50) of solid electrolytes can, for example, be 10 nm or more and 10 μm or less.

[0056] The oxide solid electrolyte can be selected from lithium lanthanum zirconate, LiPON, Li 1+X Al X Ge 2-X One or more of the following: (PO4)3, Li-SiO glass, and Li-Al-SO glass. Furthermore, combining oxide solid electrolytes with liquid electrolytes can improve ionic conductivity.

[0057] Sulfide solid electrolytes can be glass-based (sulfide glass), glass-ceramic-based, or crystalline. Sulfide glass is amorphous. Sulfide glass can have a glass transition temperature (Tg). Furthermore, when the sulfide solid electrolyte has a crystalline phase, examples of such crystalline phases include the thio-lithium superionic conductor (Thio-LISICON) type, the LGPS type, and the sulfide-germanium ore type. Sulfide solid electrolytes can be in particulate form. The average particle size (D50) of the sulfide solid electrolyte can be, for example, 10 nm or more and 100 μm or less.

[0058] Sulfide solid electrolytes may contain, for example, Li, X (where X is at least one of P, As, Sb, Si, Ge, Sn, B, Al, Ga, and In), and S. Additionally, sulfide solid electrolytes may also contain at least one of O and a halogen. Furthermore, sulfide solid electrolytes may contain S as the main component of the anionic element.

[0059] Sulfide solid electrolytes can be selected from, for example, Li2S-P2S5, Li2S-P2S5-LiI, Li2S-P2S5-GeS2, Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-P2S5-LiI-LiBr, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-ZmSn (where m and n are positive numbers, and Z is any one of Ge, Zn, and Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, and Li2S-SiS2-Li x MO y (where x and y are positive numbers, and M is any one of P, Si, Ge, B, Al, Ga, and In).

[0060] The composition of sulfide solid electrolytes is not particularly limited; examples include xLi₂S·(100-x)P₂S₅ (70≤x≤80) and yLiI·zLiBr·(100-yz)(xLi₂S·(1-x)P₂S₅) (0.7≤x≤0.8, 0≤y≤30, 0≤z≤30). Alternatively, sulfide solid electrolytes can also have the general formula: Li 4-x Ge 1-x P x The composition shown in S4 (0 < x < 1) is as follows. In the above general formula, at least a portion of Ge can be substituted with at least one of Sb, Si, Sn, B, Al, Ga, In, Ti, Zr, V, and Nb. In the above general formula, at least a portion of P can be substituted with at least one of Sb, Si, Sn, B, Al, Ga, In, Ti, Zr, V, and Nb. In the above general formula, a portion of Li can be substituted with at least one of Na, K, Mg, Ca, and Zn. In the above general formula, a portion of S can be substituted with at least one halogen (F, Cl, Br, and I). Alternatively, the sulfide solid electrolyte can have Li 7- a PS 6-a X a The composition shown is as follows: (X is at least one of Cl, Br, and I, and a is a number greater than 0 and less than 2). a can be 0 or greater than 0. In the latter case, a can be greater than 0.1, greater than 0.5, or greater than 1. Additionally, a can be less than 1.8 or less than 1.5.

[0061] Ion-bound solid electrolytes may, for example, contain at least one element selected from the group consisting of Mg, Ca, Sr, Ba, Zn, Sn, Al, Sc, Ga, Bi, Sb, Zr, Hf, Ti, Ta, Nb, W, Y, Gd, Tb, and Sm. These elements can generate cations in water. Additionally, ion-bound solid electrolyte materials may also contain at least one halide element selected from the group consisting of Cl, Br, I, and F. These elements can generate anions in water. Ion-bound solid electrolytes may contain at least one element selected from the group consisting of Gd, Ca, Zr, and Y, at least one element selected from the group consisting of Cl, Br, I, and F, and Li. Furthermore, ion-bound solid electrolytes may contain Li and Y, and may contain at least one element selected from the group consisting of Cl, Br, I, and F. More specifically, ion-bound solid electrolytes may contain Li, Y, Cl, and Br, or Li, Ca, Y, Gd, Cl, and Br, or Li, Zr, Y, and Cl. More specifically, ion-bound solid electrolytes can be Li3YBr2Cl4, Li 2.8 Ca 0.1 Y 0.5 Gd 0.5 Br2Cl4 and Li 2.5 Y 0.5 Zr 0.5 At least one of Cl6.

[0062] Ion-bound solid electrolytes can be halide solid electrolytes. Halide solid electrolytes exhibit excellent ionic conductivity. Examples of halide solid electrolytes include, for instance, formula (A): Li α M β X γ …(A) shows the composition. Here, α, β, and γ are each independently a value greater than 0, M is at least one selected from the group consisting of metallic elements other than Li and half-metallic elements, and X is at least one selected from the group consisting of Cl, Br, and I. It should be noted that "half-metallic element" can be at least one selected from the group consisting of B, Si, Ge, As, Sb, and Te. In addition, "metallic element" can include (i) all elements contained in Groups 1 to 12 of the periodic table (except hydrogen) and (ii) all elements contained in Groups 13 to 16 of the periodic table (except B, Si, Ge, As, Sb, Te, C, N, P, O, S, and Se). Metallic elements can form inorganic compounds with halide ions, and can form cations.

[0063] In formula (A), M may contain Y (i.e., yttrium). Halide solid electrolytes containing Y can have Li a Me b Y cX6 (where a+mb+3c=6, c>0, Me is at least one selected from the group consisting of metallic and half-metallic elements other than Li and Y, and m is the valence of Me) is the composition shown. Me can, for example, be at least one selected from the group consisting of Mg, Ca, Sr, Ba, Zn, Sc, Al, Ga, Bi, Zr, Hf, Ti, Sn, Ta and Nb.

[0064] Halogenated solid electrolytes can have the formula (A1): Li 6-3d Y d The composition shown in X6. In formula (A1), X is one or more elements selected from the group consisting of Cl, Br, and I. d can satisfy 0 < d < 2, or d = 1. Halogen solid electrolytes can have the following composition: Li 3-3δ Y 1+δ The composition shown in Cl6. In formula (A2), 0 < δ ≤ 0.15. Halide solid electrolytes can have formula (A3): Li 3-3δ Y 1+δ The composition shown for Br6. In formula (A3), 0 < δ ≤ 0.25. Halide solid electrolytes can have formula (A4): Li 3-3δ+a Y 1+δ-a Me a Cl 6-x-y Br x I y The composition is shown. In formula (A4), Me can be at least one selected from the group consisting of Mg, Ca, Sr, Ba, and Zn. In formula (A4), for example, -1 < δ < 2, 0 < a < 3, 0 < (3 - 3δ + a), 0 < (1 + δ - a), 0 ≤ x ≤ 6, 0 ≤ y ≤ 6, and (x + y) ≤ 6 are satisfied. Halide solid electrolytes can have formula (A5): Li 3-3δ Y 1+δ-a Me a Cl 6-x-y Br x I y The composition is shown. In formula (A5), Me can be at least one selected from the group consisting of Al, Sc, Ga, and Bi. In formula (A5), it can be -1 < δ < 1, 0 < a < 2, 0 < (1 + δ - a), 0 ≤ x ≤ 6, 0 ≤ y ≤ 6, and (x + y) ≤ 6. The halide solid electrolyte can have formula (A6): Li 3-3δ-a Y 1+δ-a Me a Cl 6-x-y Br x I yThe composition is shown. In formula (A6), Me can be at least one selected from the group consisting of Zr, Hf, and Ti. In formula (A6), it can be -1 < δ < 1, 0 < a < 1.5, 0 < (3 - 3δ - a), 0 < (1 + δ - a), 0 ≤ x ≤ 6, 0 ≤ y ≤ 6 and (x + y) ≤ 6. The halide solid electrolyte can have formula (A7): Li 3-3δ-2a Y 1+δ-a Me a Cl 6-x-y Br x I y The composition is shown. In equation (A7), Me can be at least one of the groups consisting of Ta and Nb. In equation (A7), it can be -1 < δ < 1, 0 < a < 1.2, 0 < (3 - 3δ - 2a), 0 < (1 + δ - a), 0 ≤ x ≤ 6, 0 ≤ y ≤ 6 and (x + y) ≤ 6.

[0065] Ion-bound solid electrolytes can be complex hydride solid electrolytes. Complex hydride solid electrolytes can be composed of Li ions and a complex ion containing H. The H-containing complex ion can, for example, have an element M containing at least one of a nonmetallic element, a half-metallic element, and a metallic element, and H bound to that element M. Furthermore, in the H-containing complex ion, the element M as the central element and the H surrounding element M can be covalently bonded together. Alternatively, the H-containing complex ion can also be composed of (M... m H n ) α- This indicates that m is any positive number, and n and α can be any positive numbers depending on m, the valence of element M, etc. Element M can be any nonmetallic or metallic element capable of forming a complex ion. For example, element M can contain at least one of B, C, and N as a nonmetallic element, or it can contain B. Alternatively, element M can contain at least one of Al, Ni, and Fe as a metallic element. Especially when the complex ion contains B, or contains both C and B, it is easier to ensure higher ionic conductivity. A specific example of a complex ion containing H is (CB9H). 10 ) - (CB) 11 H 12 ) - (B) 10 H 10 ) 2- (B) 12 H 12 ) 2- (BH4) - (NH2) - (AlH4) - And their combinations. Especially when using (CB9H) 10 )- (CB) 11 H 12 ) - In the case of a combination of these, higher ionic conductivity can be easily ensured. That is, complexed hydride solid electrolytes can contain Li, C, B, and H.

[0066] 1.3.2 Liquid Electrolytes

[0067] The liquid electrolyte (electrolyte) is a liquid containing lithium ions as charge carrier ions. The electrolyte can be aqueous or non-aqueous. Its composition should be the same as that known for electrolytes used in lithium-ion batteries. The electrolyte can be an electrolyte in which lithium salts are dissolved in water or a non-aqueous solvent. Examples of non-aqueous solvents include various carbonate solvents. Examples of lithium salts include lithium amide and LiPF6. The separator holding the liquid electrolyte can be any separator commonly used in batteries, such as separators made of resins like polyethylene (PE), polypropylene (PP), polyester, and polyamide. The separator can be a single-layer or multi-layer structure. Examples of multi-layer separators include two-layer PE / PP separators, or three-layer PP / PE / PP or PE / PP / PE separators. The separator can also be made of non-woven fabrics such as cellulose non-woven fabric, resin non-woven fabric, or glass fiber non-woven fabric.

[0068] 1.3.3 Other ingredients

[0069] The binder that may be included in the electrolyte layer 30 may be appropriately selected from the binders exemplified above as binders that may be included in the positive electrode active material layer 20. A single binder may be used, or two or more may be used in combination. The electrolyte layer 30 may contain various additives.

[0070] 1.4 Negative electrode

[0071] like Figure 1 As shown, the battery 100 includes a negative electrode 40. The negative electrode 40 may, for example, include a negative current collector 41 and a negative active material layer 42 in contact with the negative current collector 41. In one embodiment, the negative electrode 40 may experience lithium metal deposition during charging and lithium metal dissolution during discharging. In this case, lithium metal is considered to constitute the negative active material layer 42. Furthermore, in this case, to homogenize the deposition and dissolution of lithium metal, an intermediate layer may exist between the electrolyte layer 30 and the negative electrode 40.

[0072] 1.4.1 Negative current collector

[0073] The negative electrode current collector 41 can be any of the materials capable of functioning as a negative electrode current collector in a battery. The negative electrode current collector 41 can be a metal foil or a metal mesh, or it can be a carbon sheet. Metal foils, in particular, offer excellent operability. The negative electrode current collector 41 can be composed of two or more metal foils or sheets. Examples of metals constituting the negative electrode current collector 41 include Cu, Ni, Cr, Au, Pt, Ag, Al, Fe, Ti, Zn, Co, and stainless steel. Specifically, from the viewpoint of ensuring reduction resistance and preventing alloying with lithium, the negative electrode current collector 41 can be a current collector containing at least one metal selected from Cu, Ni, and stainless steel, particularly a current collector containing at least one metal selected from Ni and stainless steel. The negative electrode current collector 41 can have a coating on its surface. For example, the negative electrode current collector 41 can have a protective layer on its surface. In one embodiment, the negative electrode current collector 41 can have a conductive substrate selected from the aforementioned metal foil, metal mesh, or carbon sheet, and a protective layer formed on the surface of the conductive substrate. The protective layer may, for example, contain Mg. It is believed that by having a Mg-containing protective layer on the negative electrode current collector 41, the diffusion of Li on the surface of the negative electrode current collector 41 is promoted, the affinity of metallic lithium for the negative electrode current collector 41 is increased, the voids between the negative electrode current collector 41 and metallic lithium are suppressed, and metallic lithium is deposited more uniformly on the surface of the negative electrode current collector 41. Furthermore, when the negative electrode current collector 41 is composed of two or more metal foils, a layer may be formed between the two or more metal foils. The thickness of the negative electrode current collector 41 is not particularly limited. For example, it may be 0.1 μm or more, or 1 μm or more, or less than 1 mm or less than 100 μm.

[0074] 1.4.2 Negative Electrode Active Material Layer

[0075] As described above, the negative electrode active material layer 42 can be accompanied by the deposition and dissolution of metallic lithium. That is, the battery 100 can be configured such that, during charging, metallic lithium is deposited between the electrolyte layer 30 and the negative electrode current collector 41, and during discharging, the metallic lithium between the electrolyte layer 30 and the negative electrode current collector 41 dissolves (ionizes) and returns to the positive electrode. In this case, "metallic lithium" refers to lithium alloys in addition to elemental lithium. That is, in the battery 100, metallic lithium can be deposited in the form of elemental lithium or in an alloy form with other metals. Examples of lithium alloys include Li-Mg, Li-Sn, Li-Al, Li-B, Li-C, Li-Si, Li-Ca, Li-Ga, Li-Ge, Li-As, Li-Se, Li-Ru, Li-Rh, Li-Pd, Li-Ag, Li-Au, Li-Cd, Li-In, Li-Sb, Li-Ir, Li-Pt, Li-Hg, Li-Pb, Li-Bi, Li-Zn, Li-Tl, Li-Te, and Li-At. A single lithium alloy or two or more alloys can be used. The amount of metallic lithium deposited between the electrolyte layer 30 and the negative electrode current collector 41 is not particularly limited and can be adjusted appropriately according to the target battery performance. However, excessive deposited metallic lithium may lead to pressure concentration, etc. In this regard, a target for the amount of metallic lithium deposited could be to achieve a charging capacity of the battery 100 of, for example, 1 mAh / cm³. 2 Above and 5mAh / cm 2 The following quantities.

[0076] Alternatively, the negative electrode active material layer 42 may contain negative electrode active material, and optionally may also contain electrolyte, conductive additives, binders, and various additives. The content of each component in the negative electrode active material layer 42 can be appropriately determined according to the target battery performance. For example, if the solid component of the negative electrode active material layer 42 is set to 100% by mass, the content of the negative electrode active material can be 40% by mass or more, 50% by mass or more, 60% by mass or more, or 70% by mass or more, or it can be less than 100% by mass, less than 100% by mass, less than 95% by mass, or less than 90% by mass. In this case, the shape of the negative electrode active material layer 42 is not particularly limited, for example, it can be a sheet with a generally planar surface. In this case, the thickness of the negative electrode active material layer 42 is not particularly limited, for example, it can be 0.1 μm or more, 1 μm or more, 10 μm or more, or 30 μm or more, or it can be less than 2 mm, less than 1 mm, less than 500 μm, or less than 100 μm. The negative electrode active material can be any of the materials known as negative electrode active materials for batteries. For example, silicon-based active materials such as Si, Si alloys, and silicon oxide; carbon-based active materials such as graphite and hard carbon; various oxide-based active materials such as lithium titanate; and the aforementioned metallic lithium and lithium alloys can be used. A single negative electrode active material can be used alone, or two or more can be used in combination. The shape of the negative electrode active material can be the general shape of a negative electrode active material used in a battery. For example, the negative electrode active material can be in particle form. These particles can be primary particles or secondary particles formed by the aggregation of multiple primary particles. The average particle size (D50) of the negative electrode active material particles can be, for example, 1 nm or more, 5 nm or more, or 10 nm or more; alternatively, it can be 500 μm or less, 100 μm or less, 50 μm or less, or 30 μm or less. Alternatively, as mentioned above, the negative electrode active material can also be foil-shaped or film-shaped metallic lithium. That is, the negative electrode active material layer 42 can be composed of sheets of negative electrode active material. The electrolyte that can be included in the negative electrode active material layer 42 can be, for example, the aforementioned solid electrolytes, electrolyte solutions, or combinations thereof. The conductive material that may be included in the negative electrode active material layer 42 may be appropriately selected from, for example, carbon and other metal materials, as exemplified above as conductive materials that may be included in the positive electrode active material layer 20. The binder that may be included in the negative electrode active material layer 42 may be appropriately selected from, for example, the binders exemplified above as binders that may be included in the positive electrode active material layer 20. The electrolyte, conductive additive, and binder may each be used individually, or two or more may be used in combination.

[0077] 1.5 Other components

[0078] In addition to the above-described configuration, the battery 100 may also have a general battery configuration, such as tabs and terminals. The battery 100 may be a battery in which the above-described configurations are housed within an outer casing. The outer casing may be any type of known battery casing. Furthermore, two or more batteries 100 may be arbitrarily electrically connected, or arbitrarily stacked to form a battery pack. In this case, the battery pack can be housed within a known battery casing. Examples of battery 100 shapes include coin-shaped, laminated, cylindrical, and square. The battery 100 may have a constraint member for constraining the above-described configurations along the thickness direction. By applying constraint pressure through the constraint member, the internal resistance of the battery can be easily reduced. There are no particular limitations on the constraint pressure based on the constraint member. The constraint pressure based on the constraint member may be 5 MPa or less, 3 MPa or less, or 1 MPa or less. The battery 100 may be a rechargeable battery. Alternatively, the battery 100 may be a lithium-sulfur battery (LiS battery). Furthermore, the battery 100 may be a completely solid-state battery that substantially does not contain a liquid electrolyte. In addition, battery 100 can be an all-solid-state lithium-sulfur battery.

[0079] 2. Battery manufacturing method

[0080] The battery 100 can be manufactured using known methods, except for combining the aforementioned positive current collector 10 and positive active material layer 20. One embodiment of the battery 100 manufacturing method may include: S1: preparing a positive current collector 10, wherein the positive current collector 10 has a contact surface 11 that contacts the positive active material layer 20 in a subsequent process, and the arithmetic mean roughness of the contact surface 11 is 0.25 μm or more; S2: forming the positive active material layer 20 on the contact surface 11 of the positive current collector 10 to obtain a positive electrode, wherein the positive active material layer 20 contains a sulfur-based active material; S3: obtaining a laminate having the aforementioned positive current collector 10, the aforementioned positive active material layer 20, an electrolyte layer 30, and a negative electrode 40 sequentially; and S4: housing the laminate in an outer casing. In one embodiment, the battery 100 may be manufactured as follows, for example. However, the manufacturing method of battery 100 is not limited to the following methods; for example, the layers can also be formed by dry forming or the like.

[0081] (1) The metal foil is roughened so that the arithmetic mean roughness of the surface of the metal foil (e.g., Al foil) which serves as the positive current collector is 0.25 μm or more. Specific examples of roughening treatment are as described above.

[0082] (2) A slurry for the positive electrode layer is obtained by dispersing sulfur-based active materials, such as those constituting the positive electrode active material layer, in a solvent. There are no particular limitations on the solvent used at this time, and various organic solvents can be used. The slurry for the positive electrode layer is applied to the roughened surface (contact surface) of the positive electrode current collector using a doctor blade or the like, and then dried, thereby forming a positive electrode active material layer on the roughened surface (contact surface) of the positive electrode current collector, and a positive electrode is produced.

[0083] (3) Prepare a lithium foil as the negative electrode active material and combine it with a negative electrode current collector to form a negative electrode. Alternatively, disperse the negative electrode active material constituting the negative electrode active material layer in a solvent to obtain a slurry for the negative electrode layer. There are no particular limitations on the solvent used at this time; water or various organic solvents can be used. Apply the slurry for the negative electrode layer to the surface of the negative electrode current collector using a doctor blade or the like, and then let it dry, thereby forming a negative electrode active material layer on the surface of the negative electrode current collector to form a negative electrode.

[0084] (4) The layers are stacked in such a way that the electrolyte layer (solid electrolyte layer or membrane) is sandwiched between the negative electrode and the positive electrode to obtain a laminate having a negative current collector, a negative active material layer, an electrolyte layer, a positive active material layer and a positive current collector in sequence. Other components such as terminals are installed on the laminate as needed.

[0085] (5) The laminate is housed in a battery casing. In the case of an electrolyte battery, electrolyte is filled into the battery casing, the laminate is immersed in the electrolyte, and the laminate is sealed in the battery casing to make a battery.

[0086] 3. Vehicles

[0087] As described above, the battery of the present invention exhibits excellent adhesion between the positive current collector and the positive active material layer, and possesses high short-circuit withstand capacity. Such a battery can be suitably used, for example, in at least one vehicle selected from hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs). Specifically, the technology of the present invention pertains to a vehicle equipped with a battery, characterized in that the battery comprises a positive active material layer, an electrolyte layer, and a negative electrode, wherein the positive active material layer contains a sulfide-based active material, and the positive current collector has a contact surface that contacts the positive active material layer, the arithmetic mean roughness of which is 0.25 μm or more. The battery's components are as described above.

[0088] [Example]

[0089] As described above, one embodiment of the battery, etc., has been explained; however, the technology of the present invention can be modified in various ways beyond the above-described embodiment without departing from its spirit. Hereinafter, embodiments are shown and the technology of the present invention is described in more detail, but the technology of the present invention is not limited to the following embodiments.

[0090] 1. Fabrication of laminated battery cells

[0091] 1.1 Preparation of the positive current collector

[0092] As the positive current collector, a smooth Al foil without roughening treatment and a roughened Al foil with adjusted surface roughness through roughening treatment were prepared. The roughening treatment was performed by chemically dissolving the surface of the Al foil. By controlling the dissolution conditions, three types of roughened Al foil with different surface roughness were prepared. The arithmetic mean surface roughness of the smooth Al foil was 0.21 μm. The arithmetic mean surface roughnesses of the three roughened Al foils were 0.32 μm, 0.46 μm, and 0.57 μm, respectively. It should be noted that the method for measuring the arithmetic mean roughness is as described in the embodiments of this specification.

[0093] 1.2 Production of the positive electrode

[0094] Elemental sulfur (vacuum-dried at 80°C), a sulfur-containing sulfide (P2S5), and monolayer carbon nanotubes (vacuum-dried at 120°C), used as a conductive material, were weighed in a mass ratio of elemental sulfur:P2S5:monolayer carbon nanotubes = 42:35:23. The mixture was then mixed using a mortar and pestle to obtain a final mixture. 1.7 g of this mixture was added to each ball mill jar. 80g of 4mm zirconia balls were mixed using a planetary ball mill at 400rpm for a total of 36 hours. After mixing using the planetary ball mill, the mixture was dry-graded using a 38μm sieve to obtain the cathode composite material. The cathode composite material and styrene-butadiene rubber (SBR) as a binder were weighed at a mass ratio of cathode composite material: binder = 99.7:0.3, and dispersed in mesitylene as a solvent to prepare a cathode slurry. This cathode slurry was coated onto the surfaces of the smooth and roughened Al foils with a coating gap of 220μm, pre-dried at 50°C, and then formally dried at 100°C for 30 minutes to obtain a laminate of the cathode current collector and the cathode active material layer. The obtained laminate was then... The positive electrode for evaluation is obtained by punching a diameter of 11.28 mm.

[0095] 1.3 Fabrication of the electrolyte layer

[0096] The sulfide solid electrolyte and amine-modified hydrogenated butadiene rubber (BR) as the binder were weighed according to a mass ratio of 90.9:9.1 and dispersed in heptane as a solvent to prepare a solid electrolyte slurry. This solid electrolyte slurry was coated onto a release film with a coating gap of 450 μm, pre-dried at room temperature for 3 hours, and then formally dried at 165°C for 1 hour, thereby obtaining a laminate of the release film and the solid electrolyte layer. The resulting laminate was then... Two sheets were punched out at 14.5mm, with the coated surfaces overlapping each other, and pressed at 6t at room temperature. After pressing, the release film was peeled off to obtain a self-supporting sulfide solid electrolyte layer.

[0097] 1.4 Fabrication of the negative electrode

[0098] by 13mm stamped Li-Mg alloy foil, with A 14.5mm Ni foil, used as the negative electrode current collector, is punched and pressed together with a 0.1t Li-Mg alloy foil and Ni foil to form a bond, thus obtaining the negative electrode.

[0099] 1.5 Stacking and Batteryization

[0100] The aforementioned solid electrolyte layer is disposed between the positive and negative electrodes to obtain a laminate containing, in sequence, an Al foil as the positive electrode current collector, a positive electrode active material layer, a sulfide solid electrolyte layer, a Li-Mg alloy layer as the negative electrode active material layer, and a Ni foil as the negative electrode current collector. An Al tab as the positive electrode and a Ni tab as the negative electrode are respectively attached to the laminate, and the laminate is then vacuum-sealed within a laminated film. The sealed battery cell is subjected to CIP (cold isostatic pressing) at 300 MPa to fabricate a laminated battery cell for evaluation.

[0101] 2. Peel strength test

[0102] For the positive electrode fabricated as described above, the peel strength between the positive electrode current collector and the positive electrode active material was measured according to the following steps. An RZE force gauge and a motorized support manufactured by Aikoh Engineering Co., Ltd. were used as the measuring apparatus.

[0103] (1) The positive electrode is punched into 11.28mm, pressed with 6 tons.

[0104] (2) Place double-sided tape between one side and the other side of the positive electrode and the measuring device.

[0105] (3) For the measuring device, press the positive electrode held by double-sided tape with 60N.

[0106] (4) Switch the direction of force application of the measuring device from the pressing direction to the peeling direction, and measure the strength when peeling occurs between the positive current collector and the positive active material.

[0107] 3. Electrochemical Measurement

[0108] For the laminated battery cell fabricated as described above, with a cutoff voltage range of 3.1V-1.2V, 1C = 5.84mA / cm 2 With 0.584 mA / cm 2 The "short-circuit withstand capacity" of the laminated battery cell is determined by conducting a constant current charge-discharge test at 60°C according to the following procedure at a current density of (equivalent to 0.1C).

[0109] • After the laminated battery cells have been discharged to reach the specified capacity, the process moves to the charging step.

[0110] • After reaching the specified capacity (cutoff upper voltage: 3.1V) during the charging step, proceed to the next discharging step.

[0111] • Increase the specified capacity from 1.0 mAh / cm³ 2 Each cycle increases by 1.0 mAh / cm³. 2 The "short-circuit withstand capacity" is evaluated based on the specified capacity in the cycle preceding the cycle in which the short circuit occurred during the repeated discharge and charge steps.

[0112] 4. Evaluation Results

[0113] The evaluation results are shown in Table 1 below.

[0114] [Table 1]

[0115] The results shown in Table 1 reveal the following: In cathodes using sulfide-based active materials, using roughened Al foil instead of smooth Al foil as the cathode current collector increases the peel strength between the cathode current collector and the cathode active material layer. Furthermore, in the case of fabricating an all-solid-state lithium-sulfur battery by combining a sulfide-based cathode using roughened Al foil, a solid electrolyte layer, and a metallic Li anode, the battery's short-circuit withstand capacity increases compared to the case using smooth Al foil. This is believed to be because roughening the surface of the cathode current collector increases the adhesion between the cathode current collector and the cathode active material layer due to the anchoring effect. Even when the volume of the sulfide-based active material in the cathode active material layer changes with charge and discharge, the cathode current collector is less likely to peel off from the cathode active material layer, and it also suppresses or reduces the rupture of the electrolyte layer caused by the expansion of the cathode active material layer. For reference, Figure 2 Example 2 shows a SEM image obtained by observing the interface between the positive current collector and the positive active material layer. Figure 2 As shown, in the positive electrode of Example 2, the positive electrode current collector is tightly bonded to the positive electrode active material layer.

[0116] It should be noted that, as shown in Table 1, while excessively roughening the surface of the positive current collector improves peel strength and short-circuit withstand capacity compared to a smooth surface, the improvement is less significant. Excessive roughness of the positive current collector surface can lead to concerns such as reduced electron conductivity in the electrode thickness direction, increased manufacturing costs, front-end breakage due to reduced mechanical strength of the protruding portion, and increased minimum thickness due to reduced mechanical strength of the current collector itself. Therefore, from the perspective of avoiding these issues, it is unnecessary to excessively increase the surface roughness of the positive current collector.

[0117] As can be seen from the above, a battery that has a positive current collector, a positive active material layer, an electrolyte layer and a negative electrode and satisfies the following (1) to (3) can be said to be easy to separate the positive current collector from the positive active material layer even when the volume of the sulfur-based positive active material changes due to charging and discharging.

[0118] (1) The positive electrode active material layer contains sulfur-based active materials; (2) The positive current collector has a contact surface that contacts the above-mentioned positive active material layer; (3) The arithmetic mean roughness of the contact surface is above 0.25 μm.

[0119] It should be noted that, in the above embodiments, examples illustrate the positive electrode active material layer comprising sulfur-based active materials and those containing P sulfides and carbon, but the composition of the positive electrode active material layer is not limited to these. It is believed that as long as the positive electrode active material layer contains sulfur-based active materials, the effect of controlling the arithmetic mean roughness of the positive electrode current collector as described above can be obtained.

[0120] Symbol Explanation

[0121] 100 batteries

[0122] 10 Positive current collector

[0123] 20 Positive electrode active material layer

[0124] 30 Electrolyte layer

[0125] 40 Negative electrode

[0126] 41 Negative current collector

[0127] 42 Negative electrode active material layer

Claims

1. A battery comprising a positive current collector, a positive active material layer, an electrolyte layer, and a negative electrode. The positive electrode active material layer contains sulfur-based active materials. The positive current collector has a contact surface that contacts the positive active material layer. The arithmetic mean roughness of the contact surface is greater than 0.25 μm.

2. The battery according to claim 1, wherein, The positive current collector contains Al.

3. The battery according to claim 1, wherein, The arithmetic mean roughness of the contact surface is greater than 0.32 μm.

4. The battery according to claim 1, wherein, The arithmetic mean roughness of the contact surface is below 0.57 μm.

5. The battery according to claim 1, wherein, The arithmetic mean roughness of the contact surface is greater than 0.32 μm and less than 0.57 μm.

6. The battery according to any one of claims 1 to 5, wherein, The positive electrode active material layer contains P-containing sulfides and carbon.

7. The battery according to any one of claims 1 to 5, wherein, The electrolyte layer contains a solid electrolyte.

8. The battery according to any one of claims 1 to 5, wherein, The negative electrode undergoes lithium metal deposition during charging and lithium metal dissolution during discharging.

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