Battery and battery system

Abstract

This invention relates to batteries and battery systems. Batteries using a positive electrode composite material comprising a sulfur-based positive electrode active material have potential for improvement in capacity and cycle characteristics. The battery of this invention comprises a positive electrode composite material layer, an electrolyte layer, and a negative electrode. The positive electrode composite material layer comprises a sulfur-based active material and a phosphorus-containing sulfide. The positive electrode composite material layer... 31 The solid-state NMR spectrum of p satisfies I1 / I2 ≤ 8.5 (I1: originating from PS4). 3‑ The relationship between the integrated intensity of the peak and I2: the integrated intensity of the peak originating from the reduction product.

Description

Technical Field

[0001] This application discloses batteries and battery systems. Background Technology

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

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-212615 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] Batteries using cathode composite materials containing sulfur-based cathode active materials have room for improvement in terms of capacity and cycle characteristics.

[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 electrode composite material layer, an electrolyte layer, and a negative electrode, wherein the positive electrode composite material layer includes a sulfur-based active material and a phosphorus-containing sulfide. 31 The solid NMR spectrum of P satisfies the following relationship (1).

[0012] I1 / I2≤8.5 …(1)

[0013] I1: From PS4 3- The integral intensity of the peak

[0014] I2: Integrated intensity of the peak derived from the reduction product

[0015] <Method 2>

[0016] According to the battery of method 1, the aforementioned positive electrode composite material layer contains carbon nanotubes.

[0017] <Method 3>

[0018] According to method 1 or 2 of the battery, the electrolyte layer mentioned above contains a solid electrolyte.

[0019] <Method 4>

[0020] According to any one of the methods 1 to 3, the negative electrode is accompanied by the deposition of metallic lithium during charging and the dissolution of metallic lithium during discharging.

[0021] <Method 5>

[0022] A battery system includes a battery and a control unit. The battery includes a positive electrode composite layer, an electrolyte layer, and a negative electrode. The positive electrode composite layer comprises a sulfur-based active material and a phosphorus-containing sulfide. The control unit sets the cutoff potential of the positive electrode composite layer of the battery to 1.0V vs Li. + / Li above and below 1.5V vs Li + The discharge of the battery can be controlled by any potential between / Li.

[0023] Invention Effects

[0024] According to the technology of the present invention, the capacity and cycle characteristics of batteries using sulfur-based positive electrode active materials are improved. Attached Figure Description

[0025] Figure 1 This is a simplified illustration of an example of battery construction.

[0026] Figure 2 This is a simplified illustration of an example of the structure of a battery system.

[0027] Figure 3 The configuration of the compressed battery cells in the comparative examples and embodiments is shown in a schematic manner.

[0028] Figure 4 The positive electrode composite material layers of the comparative examples and embodiments are shown. 31 P solid NMR spectrum.

[0029] Figure 5 The cycle characteristics of the respective compressed battery cells in the comparative examples and embodiments are shown.

[0030] Figure 6 The XAFS measurement results of the sulfur K-absorbing edge (S K-edge) of the cathode composite materials of the comparative examples and the examples are shown.

[0031] Figure 7 The XAFS measurement results of the phosphorus K-absorbing edge (P K-edge) of the respective cathode composite materials of the comparative examples and embodiments are shown. Detailed Implementation

[0032] Hereinafter, one embodiment of the battery and battery system of the present invention will be described, but the battery and battery system of the present invention are not limited to the embodiment described below.

[0033] 1. Battery

[0034] like Figure 1As shown, a battery 100 according to one embodiment includes a positive electrode composite material layer 11, an electrolyte layer 20, and a negative electrode 30. The positive electrode composite material layer 11 comprises a sulfur-based active material and a phosphorus-containing sulfide. The positive electrode composite material layer 11... 31 The solid NMR spectrum of P satisfies the following relationship (1).

[0035] I1 / I2≤8.5 …(1)

[0036] I1: From PS4 3- The integral intensity of the peak

[0037] I2: Integrated intensity of the peak derived from the reduction product

[0038] 1.1 Positive electrode

[0039] like Figure 1 As shown, the positive electrode 10 of the battery 100 may, for example, include a positive electrode composite material layer 11 and a positive electrode current collector 12 in contact with the positive electrode composite material layer 11. The positive electrode composite material layer 11 may be formed on the surface of the positive electrode current collector 12.

[0040] 1.1.1 Positive electrode composite material layer

[0041] The positive electrode composite layer 11 contains sulfur-based active materials and phosphorus-containing sulfides. In addition to sulfur-based active materials and phosphorus-containing sulfides, the positive electrode composite layer 11 may also contain one or more of other active materials, electrolytes, conductive materials, and binders. By including sulfur-based active materials and phosphorus-containing sulfides in the positive electrode composite layer 11, the ionic conductivity of the positive electrode composite layer 11 is easily improved.

[0042] The sulfur-based active material contained in the positive electrode composite layer 11 only needs to react with Li ions (which serve as charge compensation ions) during discharge to generate compounds containing sulfur and lithium (such as sulfides like Li₂S) as discharge products, 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 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 composite layer 11 can be solid-dissolved relative to the P-containing sulfides described later, or it can be chemically bonded to the P-containing sulfides. For example, the S in the sulfur-based active material can be chemically bonded to the S in the P-containing sulfides. The shape of the sulfur-based active material contained in the positive electrode composite layer 11 is not particularly limited; for example, it can be particulate or amorphous. Whether the cathode composite layer 11 contains sulfur-based active materials can be determined by performing various analyses such as XAFS, XRD, and NMR on the cathode composite material constituting the cathode composite layer 11. For example, when the cathode composite layer 11 is composed of a cathode composite material containing elemental sulfur, when an X-ray diffraction pattern is obtained for the cathode 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 materials contained in the cathode composite layer 11 is not particularly limited and can be appropriately determined according to the target battery performance. In one embodiment, the content of sulfur-based active materials in the cathode composite layer 11 can be 10% by mass or more and less than 100% by mass, 20% by mass or more and less than 80% by mass, or 30% by mass or more and less than 60% by mass.

[0043] The P-containing sulfide contained in the positive electrode composite layer 11 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. Alternatively, the P-containing sulfide may contain P, S, and optional element M as constituent elements, but not Li. The P-containing sulfide may contain sulfides that are compounds of P and S (e.g., P2S5). Furthermore, the P-containing sulfide may also have a positive P structure (PS4 structure). Additionally, the P-containing compound may be combined with the aforementioned sulfur-based active material and amorphized, for example, P2S6. 4- P2S7 4-The form of the P-containing sulfide contained in the cathode composite layer 11 is not particularly limited; for example, it can be particle-like or amorphous. Whether the cathode composite layer 11 contains P-containing sulfides can be determined by performing various analyses such as XAFS, XRD, and NMR on the cathode composite material constituting the cathode composite layer 11. For example, when the cathode composite layer 11 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. Diffraction peaks originating from P2S5 typically appear at 2θ = 25.84° ± 0.50°, 30.35° ± 0.50°, and 31.32° ± 0.50°. Furthermore, when the cathode composite material is measured based on XAFS, peaks originating from P2S5 are identified. Furthermore, when the cathode composite material is measured by NMR, peaks originating from P2S5 are identified. The amount of phosphorus-containing sulfides contained in the cathode composite layer 11 is not particularly limited, and can be appropriately determined according to the target battery performance. In one embodiment, the content of phosphorus-containing sulfides in the cathode composite layer 11 can be greater than 0% by mass and less than 90% by mass, more than 20% by mass and less than 80% by mass, or more than 30% by mass and less than 60% by mass. In addition, the molar ratio (P / S) of phosphorus to sulfur contained in the cathode composite layer 11 is not particularly limited, and can be, for example, more than 0.03 and less than 0.50. Here, the denominator of the molar ratio (P / S) refers to the total amount of sulfur contained in the cathode composite layer 11. When the cathode composite layer 11 contains sulfur-based active materials, phosphorus-containing sulfides, and other sulfides described later, they all contain sulfur, so the total amount of these sulfur elements is used as the denominator of the molar ratio (P / S).

[0044] The positive electrode composite layer 11 may contain a conductive material. The conductive material only needs to improve the conductivity of the positive electrode composite layer 11, and can be, for example, one or more of carbon and metallic materials. Especially when the positive electrode composite layer 11 contains carbon as a conductive material, high performance is easily ensured as a battery. In one embodiment, the positive electrode composite layer 11 may also not contain conductive materials other than carbon. Carbon is, for example, elemental carbon. 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 composite layer 11 contains carbon nanotubes, high performance is easily ensured as a battery. The amount of conductive material contained in the positive electrode composite layer 11 is not particularly limited, and can be appropriately determined according to the target battery performance. In one embodiment, the content of conductive material in the positive electrode composite layer 11 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.

[0045] The positive electrode composite layer 11 may contain other active materials, other sulfides, other conductive materials, binders, and other components. The content of these other components in the positive electrode composite layer 11 is not particularly limited. Other active materials may be, for example, various lithium-containing compounds. These lithium-containing compounds may be lithium cobalt oxide, lithium nickel oxide, or Lithium oxide. 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-containing 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 composite material layer 11 to expand and contract during charging and discharging, and the easier it is for the cycle characteristics to decrease. However, according to this embodiment, as described below, by making the positive electrode composite material layer 11... 31 The solid NMR spectrum of P satisfies a predetermined relationship (1), which easily improves the cycle characteristics of the battery. Other sulfides may contain at least element M (M is, for example, one or more of Ge, Sn, Si, B and Al) and S as constituent elements. Other sulfides may also contain the positive structure of element M. For example, the positive structure of element M can be one or more of GeS4 structure, SnS4 structure, SiS4 structure, BS3 structure and AlS3 structure. In addition, other sulfides may also contain sulfides that are compounds of elements M and S (M x S y Here, 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. The adhesive can be, for example, one or more selected from butadiene rubber (BR) adhesives, butene rubber (IIR) adhesives, acrylate butadiene rubber (ABR) adhesives, styrene butadiene rubber (SBR) adhesives, polyvinylidene fluoride (PVdF) adhesives, polytetrafluoroethylene (PTFE) adhesives, and polyimide (PI) adhesives.

[0046] Positive electrode composite layer 11 31 The P solid-state NMR spectrum satisfies the above relationship (1). That is, in the cathode composite material layer 11...31 In the P solid-state NMR spectrum, the integrated intensity relative to the peak originating from the reduction product is from PS4. - The integrated intensity of the peak is below a certain value. As described later, for a battery having a positive electrode composite material layer containing sulfide active materials and P-containing sulfides, by controlling the cutoff potential during discharge, an ion-conducting phase as a reduction product is formed in the positive electrode composite material layer 11, thereby improving the ion conductivity of the positive electrode composite material layer 11. As a result, the utilization rate of the sulfide active materials increases, and the battery capacity and cycle characteristics improve. In other words, the positive electrode composite material layer 11... 31 The solid-state NMR spectrum of P satisfies the above relationship (1), which means that the ion-conducting phase, which is a reduction product, is self-formed in the cathode composite material layer 11, that is, the ion conductivity of the cathode composite material layer 11 is improved, the utilization rate of chalcogenide compounds is increased, and it is easy to ensure excellent capacity and cycling characteristics. It should be noted that "reduction product" is considered to be formed through PS4 3- Substances formed by the reduction of (e.g., Li3PS4).

[0047] In the above relationship (1), the lower limit of I1 / I2 is not specifically limited. I1 / I2 can be 0 or higher, 0.5 or higher, 1.0 or higher, 1.5 or higher, 2.0 or higher, 2.5 or higher, 3.0 or higher, 3.5 or higher, or 4.0 or higher. The positive electrode composite material layer 11... 31 The solid-state NMR spectrum of p can satisfy any of the following relationships (1-1) to (1-22). In this case, it is easy to ensure better capacity and cycling characteristics.

[0048] 0.5≤I1 / I2≤8.0 …(1-1)

[0049] 0.5≤I1 / I2≤7.5 …(1-2)

[0050] 0.5≤I1 / I2≤7.0 …(1-3)

[0051] 0.5≤I1 / I2≤6.5 …(1-4)

[0052] 0.5≤I1 / I2≤6.0 …(1-5)

[0053] 0.5≤I1 / I2≤5.5 …(1-6)

[0054] 0.5≤I1 / I2≤5.0 …(1-7)

[0055] 0.5≤I1 / I2≤4.5 …(1-8)

[0056] 1.0≤I1 / I2≤8.0 …(1-9)

[0057] 1.5≤I1 / I2≤8.0 …(1-10)

[0058] 2.0≤I1 / I2≤8.0 …(1-11)

[0059] 2.5≤I1 / I2≤8.0 …(1-12)

[0060] 3.0≤I1 / I2≤8.0 …(1-13)

[0061] 3.5≤I1 / I2≤8.0 …(1-14)

[0062] 4.0≤I1 / I2≤8.0 …(1-15)

[0063] 1.0≤I1 / I2≤7.5 …(1-16)

[0064] 1.5≤I1 / I2≤7.0 …(1-17)

[0065] 2.0≤I1 / I2≤6.5 …(1-18)

[0066] 2.5≤I1 / I2≤6.0 …(1-19)

[0067] 3.0≤I1 / I2≤5.5 …(1-20)

[0068] 3.5≤I1 / I2≤5.0 …(1-21)

[0069] 4.0≤I1 / I2≤4.5 …(1-22)

[0070] Positive electrode composite layer 11 31 The conditions for obtaining P solid-state NMR spectra are as follows.

[0071] (I) Obtain the positive electrode composite material powder from the positive electrode composite material layer 11.

[0072] (II) Under an Ar atmosphere, add about 25 μL of the powder to a 3.2 mm solid NMR sample tube.

[0073] (III) Using the ECA-500 FT-NMR manufactured by NEC Corporation, the following conditions were met at room temperature. 31 P solid-state NMR determination.

[0074] Probe: 3.2mm CPMAS probe

[0075] Magnetic field strength: 11.747 T (202.4 MHz for the 31P core)

[0076] Observation frequency range: -450ppm to 550ppm

[0077] Data points: 2048

[0078] Measurement mode: Single pulse

[0079] Repeat time: 300 seconds

[0080] Total number of tests: 64 (measurement time: 5.5 hours)

[0081] Reference material: Ammonium dihydrogen phosphate (external reference: 1.33 ppm)

[0082] MAS speed: 18kHz

[0083] (IV) 31 After obtaining the spectrum by solid-state NMR measurement, and after baseline correction, I1 and I2 are obtained by waveform separation using Gaussian function and calculation of the integral intensity of each peak.

[0084] It should be noted that the results obtained under the above conditions 31 In the P solid NMR spectrum, the source is PS4 3- The peaks from the reduction product appeared in the range of 80–84 ppm, while those from the reduction product appeared in the range of 70–78 ppm. That is, the peaks from the reduction product were located at a higher concentration than those from the PS4 source. 3- The peak is at a slightly smaller chemical shift. Obtained under the above conditions. 31 In the P solid NMR spectrum, the source is PS4 3- The peaks from the reduction product and those from the PS4 can overlap. In this case, the larger the peak from the reduction product, the more pronounced the overlap. 3- The proportion of shoulder peaks on the side with smaller chemical shifts increases.

[0085] In one embodiment, the cathode composite material constituting the cathode composite material layer 11 showed a peak with a apex in the range of 2144 eV and below 2147 eV in the XAFS measurement results of the phosphorus K absorption edge (P K-edge).

[0086] The shape and thickness of the positive electrode composite layer 11 are not particularly limited, and can be appropriately determined by considering the target battery performance. The positive electrode composite layer 11 can be a sheet with a generally flat surface. The thickness of the positive electrode composite layer 11 can be, for example, 0.1 μm or more, 1 μm or more, 10 μm or more, or 30 μm or more, and can be less than 2 mm, less than 1 mm, less than 500 μm, or less than 100 μm.

[0087] 1.1.2 Positive Current Collector

[0088] like Figure 1As shown, the positive electrode 10 of the battery 100 may have a positive electrode current collector 12 in contact with the positive electrode composite material layer 11. The constituent material, shape, and size of the positive electrode current collector 12 are not particularly limited. The positive electrode current collector 12 may be, for example, foil or plate-shaped. The positive electrode current collector 12 may be a metal foil. Alternatively, the positive electrode current collector 12 may have a layer formed of a resin composition comprising a resin and a conductive material. Alternatively, the positive electrode current collector 12 may comprise a combination of a metal foil and a layer formed of a resin composition. The positive electrode current collector 12 may be composed of two or more foils or sheets. As the metal constituting the metal foil serving as the positive electrode current collector 12, at least one selected from Cu, Ni, Cr, Au, Pt, Ag, Al, Fe, Ti, Zn, Co, V, Mg, Pb, Ge, In, Sn, Zr, and stainless steel may be included. Particularly from the viewpoint of ensuring oxidation resistance, the positive electrode current collector 12 may contain Al. The positive current collector 12 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 12 is composed of two or more metal foils, a layer may be formed between the two or more metal foils. The thickness of the positive current collector 12 is not particularly limited. For example, the thickness of the positive current collector 12 can be 1 μm or more and 1 mm or less.

[0089] 1.2 Electrolyte Layer

[0090] like Figure 1As shown, the electrolyte layer 20 is disposed between the positive electrode composite layer 11 and the negative electrode 30. The electrolyte layer 20 contains at least an electrolyte. The electrolyte layer 20 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 20 contains a solid electrolyte, it is easy to ensure higher performance. The electrolyte layer 20 may be a solid electrolyte layer without liquid electrolyte. According to the technology of the present invention, it is not easy for the solid electrolyte layer to break during the charging and discharging of the battery. Alternatively, the electrolyte layer 20 may also have a separator, etc., for retaining the liquid electrolyte and preventing contact between the positive electrode composite layer 11 and the negative electrode 30. The thickness of the electrolyte layer 20 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 20 may be composed of one layer or two or more layers. For example, the electrolyte layer 20 may have a first layer disposed on the positive electrode composite layer 11 side and a second layer disposed on the negative electrode 30 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 may be different types from 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.

[0091] 1.2.1 Solid Electrolytes

[0092] 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 particle form. The average particle size (D50) of solid electrolytes can, for example, be 10 nm or more and 10 μm or less.

[0093] The oxide solid electrolyte can be selected from lithium lanthanum zirconate, LiPON, Li 1+X Al X Ge 2-XOne 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.

[0094] Sulfide solid electrolytes can be glassy sulfide solid electrolytes (sulfide glasses), glass-ceramic sulfide solid electrolytes, or crystalline sulfide solid electrolytes. Sulfide glasses are amorphous. Sulfide glasses can have a glass transition temperature (Tg). Furthermore, when the sulfide solid electrolyte has a crystalline phase, examples of 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.

[0095] 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.

[0096] 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).

[0097] 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.

[0098] 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 0.1Y 0.5 Gd 0.5 Br2Cl4 and Li 2.5 Y 0.5 Zr 0.5 At least one of Cl6.

[0099] 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 elements" can be at least one selected from the group consisting of B, Si, Ge, As, Sb, and Te. In addition, "metallic elements" can include (i) all elements contained in Groups 1 to 12 of the periodic table (except for hydrogen) and (ii) all elements contained in Groups 13 to 16 of the periodic table (except for B, Si, Ge, As, Sb, Te, C, N, P, O, S, and Se). Metallic elements can form inorganic compounds with halide ions, and can also form cations.

[0100] In formula (A), M may contain Y (i.e., yttrium). Halide solid electrolytes containing Y can have Li a Me b Y c X6 (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.

[0101] 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+δThe 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 y The 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.

[0102] 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.

[0103] 1.2.2 Liquid Electrolytes

[0104] 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 structures like PE / PP, or three-layer structures like PP / PE / PP or PE / PP / PE. 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.

[0105] 1.3.3 Other ingredients

[0106] The binder that may be included in the electrolyte layer 20 may be appropriately selected from the binders exemplified above as binders that may be included in the positive electrode composite layer 11. A single binder may be used, or two or more may be used in combination. The electrolyte layer 20 may contain various additives.

[0107] 1.3 Negative electrode

[0108] like Figure 1 As shown, the negative electrode 30 of the battery 100 may, for example, include a negative electrode active material layer 31 and a negative electrode current collector 32 in contact with the negative electrode active material layer 31. In one embodiment, the negative electrode 30 may be accompanied by the deposition of lithium metal during charging and the dissolution of lithium metal during discharging. In this case, lithium metal is considered to constitute the negative electrode active material layer 31. In addition, in this case, in order to homogenize the deposition and dissolution of lithium metal, an intermediate layer may exist between the electrolyte layer 20 and the negative electrode 30. There is no particular limitation on the type of intermediate layer, which may be a layer containing elements that can alloy with lithium metal.

[0109] 1.3.1 Negative Electrode Active Material Layer

[0110] As described above, the negative electrode active material layer 31 may 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 20 and the negative electrode current collector 32, and during discharging, the metallic lithium between the electrolyte layer 20 and the negative electrode current collector 32 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 20 and the negative electrode current collector 32 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.

[0111] Alternatively, the negative electrode active material layer 31 may contain a negative electrode active material, and optionally may also contain an electrolyte, conductive additives, binders, and various additives. The content of each component in the negative electrode active material layer 31 can be appropriately determined according to the target battery performance. For example, if the solid content of the negative electrode active material layer 31 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 31 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 31 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 31 can be composed of sheets of negative electrode active material. The electrolyte that can be included in the negative electrode active material layer 31 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 31 can be appropriately selected from carbon and other metal materials, as exemplified above as conductive materials that may be included in the positive electrode composite material layer 11. The binder that may be included in the negative electrode active material layer 31 can be appropriately selected from the binders exemplified above as binders that may be included in the positive electrode composite material layer 11. The electrolyte, conductive additive, and binder may each be used individually, or two or more may be used in combination.

[0112] 1.3.2 Negative current collector

[0113] The negative electrode current collector 32 can be any material capable of functioning as a negative electrode current collector in a battery. The negative electrode current collector 32 can be a metal foil or metal mesh, or it can be a carbon sheet. Metal foils, in particular, offer excellent operability. The negative electrode current collector 32 can be composed of two or more metal foils or sheets. Examples of metals constituting the negative electrode current collector 32 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 32 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 32 can have a coating on its surface. For example, the negative electrode current collector 32 can have a protective layer on its surface. In one embodiment, the negative electrode current collector 32 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 32, the diffusion of Li on the surface of the negative electrode current collector 32 is promoted, the affinity of metallic lithium for the negative electrode current collector 32 is increased, the voids between the negative electrode current collector 32 and metallic lithium are suppressed, and metallic lithium is deposited more uniformly on the surface of the negative electrode current collector 32. Furthermore, when the negative electrode current collector 32 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 32 is not particularly limited. For example, it may be 0.1 μm or more, or 1 μm or less, or 1 mm or less, or 100 μm or less.

[0114] 1.4 Other components

[0115] 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 solid-state battery that substantially does not contain a liquid electrolyte. In addition, battery 100 can be an all-solid-state lithium-sulfur battery.

[0116] 2. Battery manufacturing method

[0117] In addition to having the aforementioned positive electrode composite material layer, the battery 100 can be manufactured using known methods. In one embodiment, the battery 100 can be manufactured as follows. However, the manufacturing method of the battery 100 is not limited to the following methods; for example, the layers can also be formed by dry forming or the like.

[0118] (1) A slurry for the positive electrode layer is obtained by dispersing sulfur-based active materials, etc., constituting the positive electrode composite 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 composite material layer on the roughened surface (contact surface) of the positive electrode current collector, and a positive electrode is produced.

[0119] (2) Prepare a lithium metal 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.

[0120] (3) 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 electrode current collector, a negative electrode active material layer, an electrolyte layer, a positive electrode composite material layer and a positive electrode current collector in sequence. Other components such as terminals are installed on the laminate as needed.

[0121] (4) The laminate is housed in the 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.

[0122] (5) After sealing, discharge is performed while controlling the cutoff potential of the positive electrode composite material layer. An ion-conducting phase, which is a reduction product, is formed in the positive electrode composite material layer, thereby improving the ion conductivity of the positive electrode composite material layer and obtaining a battery with excellent capacity and cycle characteristics. The discharge conditions are described later.

[0123] 3. Battery System

[0124] In addition to its aspects as a battery as described above, the technology of this invention also has aspects as a battery system. For example... Figure 2 As shown, one embodiment of the battery system includes a battery 100 and a control unit 200. The battery 100 includes a positive electrode composite material layer 11, an electrolyte layer 20, and a negative electrode 30. The positive electrode composite material layer 11 comprises a sulfur-based active material and a P-containing sulfide. The control unit 200 sets the cutoff potential of the positive electrode composite material layer 11 of the battery 100 to 1.0V vs Li. + / Li above and below 1.5V vs Li + The discharge of the battery 100 is controlled by any potential between / Li.

[0125] The control unit 200 only needs to be able to control the minimum discharge of the battery 100. The control unit 200 may include, for example, an ECU (Electronic Control Unit) and a PCU (Power Control Unit). For example, the control unit 200 may measure the potential of the positive electrode 10 of the battery 100 sequentially during discharge, continuing discharge if the measured potential of the positive electrode 10 exceeds a threshold, and stopping discharge when the measured potential of the positive electrode 10 reaches the threshold. In addition to controlling the discharge of the battery 100, the control unit 200 can also control charging. When the battery 100 is charged by the control unit 200, the charging cutoff potential is not particularly limited; an appropriate cutoff potential can be adopted as long as the degradation and decomposition of the battery materials are taken into account.

[0126] By controlling the discharge cutoff potential of the battery 100 using the control unit 200 as described above, an ion-conducting phase, which is a reduction product, is formed in the positive electrode composite material layer 11. This improves the ion conductivity of the positive electrode composite material layer 11, resulting in increased utilization of the sulfide active material and a battery 100 with excellent capacity and cycle characteristics. If the cutoff potential is less than 1.5V vs Li + When the capacitance is 1.0V vs. Li, the discharge capacity tends to increase significantly, including the reduction reaction of the electrochemically formed ion-conducting phase. On the other hand, if the cutoff potential is 1.0V vs. Li... + With a capacitance of 1.0 V / Li, the self-decomposition of the electrochemically formed ion-conducting phase can be suppressed, easily achieving a balance between high discharge capacity and excellent cycle characteristics. In other words, by setting the cutoff potential to 1.0 V vs Li... + / Li above and below 1.5V vs Li + The discharge of battery 100 is controlled by any potential between / Li, and the ion-conducting phase, as a reduction product, exists in the positive electrode composite material layer 11 of battery 100 in an appropriate state. 31 The solid-state NMR spectrum of P satisfies the above relationship (1). In one embodiment, the control unit 200 can make the cutoff potential of the positive electrode composite material layer 11 of the battery 100 greater than 1.0V vs Li + / Li and 1.4V vs Li + Any potential between / Li, 1.1V vs Li + / Li and above 1.3V vs Li + Any potential between / Li and below, or 1.2V vs Li + The discharge of battery 100 is controlled by the / Li method.

[0127] 4. Vehicles

[0128] As described above, the battery of the present invention has excellent cycle characteristics. 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). That is, the technology of the present invention is a vehicle having a battery, characterized in that the battery has a positive electrode composite material layer, an electrolyte layer, and a negative electrode, wherein the positive electrode composite material layer comprises a sulfur-based active material and a P-containing sulfide, and the positive electrode composite material layer... 31The P solid-state NMR spectrum satisfies the above relationship (1). The battery components are as described above. Furthermore, the technology of the present invention pertains to a vehicle having a battery system, characterized in that the battery system includes a battery and a control unit, the battery includes a positive electrode composite material layer, an electrolyte layer, and a negative electrode, the positive electrode composite material layer comprises a sulfide-based active material and a P-containing sulfide, and the control unit sets the cutoff potential of the positive electrode composite material layer of the battery to 1.0V vs Li. + / Li above and less than 1.5V vsLi + The discharge of the battery is controlled by any potential between / Li. The components of the battery system are as described above.

[0129] [Example]

[0130] As described above, one embodiment of the battery and battery system has been explained, but 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.

[0131] 1. Fabrication of positive electrode composite materials

[0132] Elemental sulfur (vacuum-dried at 80°C), serving as a sulfur-based active substance, P2S5 (containing P-sulfides), and monolayer carbon nanotubes (vacuum-dried at 120°C), serving as a conductive material, were weighed in a mass ratio of elemental sulfur:P2S5:monolayer carbon nanotubes = 42:35:23. The mixture was then combined 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 36 hours. After mixing using the planetary ball mill, the mixture was dry-graded using a 38μm sieve to obtain the cathode composite material.

[0133] 2. Fabrication of pressed battery cell A

[0134] Using the positive electrode composite material prepared as described above, follow these steps to produce... The pressed battery cell A has a diameter of 11.28 mm. The structure of the pressed battery cell A is as follows: Figure 3 As shown.

[0135] (1) Add 100mg of sulfide solid electrolyte to the battery cell and press it with 1 ton.

[0136] (2) 7.6 mg of positive electrode composite material was added to the upper side of the sulfide solid electrolyte layer in the battery cell and pressed with 1 ton.

[0137] (3) Apply a solution to the upper side of the positive electrode composite material layer inside the battery cell. Al foil cut to 11.28mm is pressed with 6 tons.

[0138] (4) Add the following to the lower side of the sulfide solid electrolyte layer in the battery cell in sequence: Li-10 wt% Mg alloy foil (100μm thick) and Ni foil, cut from 11.28mm, are pressed at 1 ton.

[0139] (5) A fixed-size constraint was applied with a constraint pressure of 2 Nm (equivalent to about 30 MPa) to obtain the pressed battery cell A for evaluation.

[0140] 3. Fabrication of pressed battery cell B

[0141] Using the positive electrode composite material prepared as described above, follow these steps to produce... The pressed battery cell B has a diameter of 11.28 mm. The structure of the manufactured pressed battery cell B is similar to that of the pressed battery cell A, as follows: Figure 3 As shown.

[0142] (1) Add 120mg of sulfide solid electrolyte to the battery cell, press it with 1 ton, keep it for 1 minute, then press it with 4 tons without releasing the pressure, and keep it for 1 minute.

[0143] (2) Substituting into the lower side of the sulfide solid electrolyte layer in the battery cell in sequence... Li-10 wt% Mg alloy foil (100μm thick) and Ni foil, cut from 11.28mm, are pressed at 1 ton and held for 10 seconds.

[0144] (3) To 15.3 mg of positive electrode composite material was added into an 8 mm three-segment pressing fixture, pressed with 3 tons for 1 minute to obtain positive electrode composite material particles.

[0145] (4) Take out the obtained positive electrode composite material particles and scrape off the burrs.

[0146] (5) Add positive electrode composite material particles and... Al foil cut to 11.28mm.

[0147] (6) A fixed-size constraint of 2 Nm (equivalent to about 30 MPa) was applied to obtain the pressed battery cell B for evaluation.

[0148] 4. Evaluation Methods

[0149] 4.1 Electrochemical Measurement

[0150] For the pressed battery cell A fabricated as described above, the upper limit cutoff potential for charging is set to 3.1V, and the lower limit cutoff potential for discharging is set to 1.5V vs Li. + / Li (Comparative Example 1), 1.2V vs Li + / Li (Example 1) or 1.0V vs Li + / Li (Example 2), set as 1C = 5.84mA / cm 2 The constant current charge-discharge test shall be carried out at 60℃ in accordance with the following procedure.

[0151] (1) Adjustment (1.2V discharge) and cycles 1-3: Current density 0.584 mA / cm² 2 This is equivalent to 0.1C; (2) Cycles 4-22: Current density 1.168 mA / cm² 2 This is equivalent to 0.2C; (3) 23rd cycle: Current density 0.584 mA / cm² 2 This is equivalent to 0.1C; (4) Cycles 24–42: Current density 1.168 mA / cm² 2 This is equivalent to 0.2C; (5) 43rd cycle: Current density 0.584 mA / cm² 2 This is equivalent to 0.1C; (6) Cycles 44-50: Current density 1.168 mA / cm² 2 This is equivalent to 0.2C.

[0152] 4.2 31 P solid-state NMR determination

[0153] For the pressed battery cell B manufactured as described above, with a current density of 0.298 mA / cm² 2 This is equivalent to 0.025C (1C = 11.93 mA / cm). 2 A constant current discharge test was conducted at 60℃. The lower limit cutoff potential of the discharge was set to 1.5V vs Li. + / Li (Comparative Example 1), 1.2V vs Li + / Li (Example 1) or 1.0V vs Li + / Li (Example 2), after reaching the lower limit cutoff potential, it was maintained for 1 hour. Then, the positive electrode composite material particles were recovered from the pressed battery cell B, crushed and mixed using a mortar and pestle to obtain positive electrode composite material powder. The obtained positive electrode composite material powder was then subjected to... 31P solid-state NMR determination. Measurement conditions are as described in the embodiments of this specification.

[0154] 4.3 XAFS determination

[0155] For the pressed battery cell B manufactured as described above, with a current density of 0.298 mA / cm² 2 This is equivalent to 0.025C (1C = 11.93 mA / cm). 2 A constant current discharge test was conducted at 60℃. At this time, the lower cutoff potential was set to 2.1V vs Li. + / Li (Comparative Example 3), 1.8V vs Li + / Li (Comparative Example 2), 1.5V vs Li + / Li (Comparative Example 1), 1.4V vs Li + / Li (Example 3), 1.2V vs Li + / Li (Example 1) or 1.0V vs Li + / Li (Example 2), after reaching the lower limit cutoff potential, it was held for 1 hour. Then, the positive electrode composite material particles were recovered from the pressed battery cell B, crushed and mixed using a mortar, to obtain positive electrode composite material powder. For the obtained positive electrode composite material powder, XAFS measurements of the sulfur K absorption edge (S K-edge) and phosphorus K absorption edge (P K-edge) were performed under the following conditions. In addition, the same XAFS measurement was also performed on the positive electrode composite material particles of the pressed battery cell B before discharge (refer to Example 1).

[0156] Beam size: 1 mm (V) × 2 mm (H) at the sample position.

[0157] Spectroscopic crystal: InSb(111)

[0158] Measurement methods: Total electron yield (TEY; analytical depth tens of nm) / Partial fluorescence yield (PFY; analytical depth several μm)

[0159] Note: Using a vacuum chamber

[0160] 4. Evaluation Results

[0161] Figure 4 In the examples, the positive electrode composite materials of the pressed battery cell B in Comparative Example 1, Example 1, and Example 2 are shown. 31 P solid-state NMR spectra. Additionally, Table 1 below shows the respective NMR spectra of P. 31 The integrated intensity obtained from the P solid NMR spectrum, i.e., "derived from PS4" 3- The integrated intensity I1 of the peak and the integrated intensity I2 of the peak originating from the reduction product. Additionally, Figure 5The cycle characteristics of the pressed battery cell A in Comparative Examples 1, 1, and 2 are shown. Furthermore, Table 1 below shows the discharge capacity C0 at adjustment, the discharge capacity C1 in the first charge-discharge cycle, and the discharge capacity C50 in the 50th charge-discharge cycle for each pressed battery cell A. Figure 6 The XAFS measurement results of the sulfur K-absorbing edge (SK-edge) of the positive electrode composite material of the pressed battery cell B in Comparative Examples 1-3 and Examples 1-3 are shown. Figure 7 The results of XAFS measurements of the phosphorus K absorption edge (P K-edge) are shown.

[0162] [Table 1]

[0163] As shown in Table 1 and Figure 4 As shown, as the cutoff potential decreases, the ratio is considered to originate from PS4. 3- The peak of the reduction product originated from PS4. 3- The proportion of peaks (shoulder peaks) at slightly smaller chemical shifts increases, and the integrated intensity ratio I1 / I2 changes.

[0164] As shown in Table 1 and Figure 5 As shown, when discharging a battery having a positive electrode composite material layer containing sulfur-based active materials and P-sulfides, the lower the cutoff voltage, the greater the discharge capacity during the initial adjustment and the first cycle after adjustment (Examples 1 and 2).

[0165] like Figure 6 and 7 As shown, it can be seen that when the cutoff potential is less than 1.5V, vs Li + In the case of / Li, the decrease in the peak originating from Li3PS4 generated in the initial stage of discharge occurs simultaneously with the increase in the peak originating from Li2S and the peak originating from the reduction product of Li3PS4. That is, it is assumed that the discharge capacity increases due to the decrease in cutoff potential, including the reduction reaction of the electrochemically formed ion-conducting phase. More specifically, such as... Figure 7 As shown, in the XAFS measurements of the phosphorus K absorption edge (P K-edge), Examples 1-3 confirmed peaks with apexes in the range above 2144 eV and below 2147 eV. This peak only occurs at cutoff potentials less than 1.5 V vs Li. + The / Li case was observed and is considered to indicate that the PS4 3- The restoration.

[0166] On the other hand, regarding the discharge capacity in the adjusted 50th cycle, Example 1 (1.2V cutoff) was higher than Example 2 (1.0V cutoff). This is believed to be due to the self-decomposition of the electrochemically formed ion-conducting phase at low potential.

[0167] As described above, a battery that has a positive electrode composite layer, an electrolyte layer and a negative electrode and meets the following (I) and (III) can be said to have excellent capacity and cycle characteristics.

[0168] (I) The above-mentioned positive electrode composite material layer contains sulfur-based active materials and P-containing sulfides.

[0169] (II) The above-mentioned positive electrode composite material layer 31 The solid NMR spectrum of P satisfies the following relationship (1).

[0170] I1 / I2≤8.5 …(1)

[0171] I1: From PS4 3- The integral intensity of the peak

[0172] I2: Integrated intensity of the peak derived from the reduction product

[0173] It should be noted that, in the above embodiments, the cathode composite material layer is illustrated as containing sulfur-based active materials, P-containing sulfides, and carbon, but the composition of the cathode composite material layer is not limited to this. It is believed that as long as the cathode composite material layer contains sulfur-based active materials and P-containing compounds and satisfies the above relationship (1), excellent cycle characteristics can be ensured.

[0174] Symbol Explanation

[0175] 100 batteries

[0176] 10 Positive electrode

[0177] 11 Positive electrode composite material layer

[0178] 12 Positive current collector

[0179] 20 Electrolyte layer

[0180] 30 Negative electrode

[0181] 31 Negative Electrode Active Material Layer

[0182] 32 Negative current collector

[0183] 200 Control Department

Claims

1. A battery comprising a positive electrode composite material layer, an electrolyte layer, and a negative electrode. The positive electrode composite material layer contains sulfur-based active materials and phosphorus-containing sulfides. The positive electrode composite layer 31 The P solid NMR spectrum satisfies the following relationship (1), I1 / I2≤8.5 …(1) I1: the integrated intensity of the peak derived from PS4 3- I1 / I2: the ratio of the integrated intensity of the peak derived from PS4 to the integrated intensity of the peak I2: The integral intensity of the peak derived from the reduction product.

2. The battery according to claim 1, wherein, The positive electrode composite material layer contains carbon nanotubes.

3. The battery according to claim 1, wherein, The electrolyte layer contains a solid electrolyte.

4. The battery according to any one of claims 1 to 3, wherein, The negative electrode undergoes lithium metal deposition during charging and lithium metal dissolution during discharging.

5. A battery system comprising a battery and a control unit, The battery comprises a positive electrode composite material layer, an electrolyte layer, and a negative electrode. The positive electrode composite material layer contains sulfur-based active materials and phosphorus-containing sulfides. The control section controls discharge of the battery in such a manner that the cut-off potential of the positive electrode composite layer of the battery is 1.0 V vs Li + more than 1.5 V vs Li + any potential between 1.0 V vs Li and less than 1.5 V vs Li.

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