Battery

Abstract

To provide a battery with excellent cycle characteristics. [Solution] A battery having a positive electrode layer, an electrolyte layer, and a negative electrode layer, wherein the positive electrode layer contains a positive electrode active material and an additive, the positive electrode active material contains an S element, and the additive contains a Cl element and at least one metal element selected from the group consisting of an Mn element, an Y element, an Sn element, a V element, an Nb element, and a Ta element, and the proportion of the additive in the positive electrode layer is less than 10 mass%.

Description

[Technical Field]

[0001] The present disclosure relates to batteries. [Background technology]

[0002] Various technologies have been proposed for batteries such as those disclosed in Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-212615 [Non-patent literature]

[0004] [Non-Patent Document 1] Tatsuki Shigedomi et al., Chem. Mater. 2022, 34, 9745-9752 “Li2S-V2S3-LiI Bifunctional Material as the Positive Electrode in the All-Solid-State Li / S Battery” Summary of the Invention [Problem to be solved by the invention]

[0005] Batteries that use conventional sulfur-based positive electrode active materials containing elemental sulfur in the positive electrode layer have a low utilization rate of the positive electrode active material due to a lack of ion conduction paths to the sulfur-based positive electrode active material in the positive electrode layer, and there is room for improvement in the discharge capacity and cycle characteristics of the battery.

[0006] The present disclosure has been made in view of the above circumstances, and has as its main object to provide a battery with excellent cycle characteristics. [Means for solving the problem]

[0007] That is, the present disclosure includes the following aspects. <1> A battery having a positive electrode layer, an electrolyte layer, and a negative electrode layer, the positive electrode layer includes a positive electrode active material and an additive, The positive electrode active material contains an S element, the additive material contains a Cl element and at least one metal element selected from the group consisting of a Mn element, a Y element, a Sn element, a V element, a Nb element, and a Ta element; A battery in which the proportion of the additive in the positive electrode layer is less than 10 mass %.

[0008] <2> A battery having a positive electrode layer, an electrolyte layer, and a negative electrode layer, the positive electrode layer includes a positive electrode active material and an additive, The positive electrode active material contains an S element, the additive material contains a Cl element and at least one metal element selected from the group consisting of an Mg element and an In element, A battery in which the proportion of the additive in the positive electrode layer is 15 mass % or less.

[0009] <3> The proportion of the additive in the positive electrode layer is 1% by mass or more and 5% by mass or less. <1> or <2> The battery described in

[0010] <4> the negative electrode layer contains a negative electrode active material, The negative electrode active material is at least one of Li elemental material and a Li alloy. <1> or <2> The battery described in

[0011] <5> <1> or <2> wherein the electrolyte layer is a solid electrolyte layer containing a solid electrolyte. [Effects of the Invention]

[0012] The present disclosure has an effect of making it possible to obtain a battery with excellent cycle characteristics. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic cross-sectional view illustrating a battery according to the present disclosure. [Figure 2] FIG. 2 is a graph showing the relationship between the number of charge / discharge cycles and the discharge capacity based on the mass of the positive electrode layer excluding the mass of the additive, for an all-solid-state battery in which the additive is VCl 3 . [Figure 3] FIG. 3 is a graph showing the relationship between the number of charge / discharge cycles and the discharge capacity based on the mass of the positive electrode layer excluding the mass of the additive, for an all-solid-state battery in which the additive is NbCl 5 . [Figure 4] FIG. 4 is a graph showing the relationship between the number of charge / discharge cycles and the discharge capacity based on the mass of the positive electrode layer excluding the mass of the additive, for all-solid-state batteries in which the additive is TaCl5. [Figure 5] FIG. 5 is a graph showing the relationship between the number of charge / discharge cycles and the discharge capacity based on the mass of the positive electrode layer including the mass of the additive, for all-solid-state batteries in which the additive is VCl 3 . DETAILED DESCRIPTION OF THE INVENTION

[0014] Embodiments of the present disclosure are described below. Matters necessary for implementing the present disclosure other than those specifically mentioned in this specification (e.g., general battery configurations and manufacturing processes that do not characterize the present disclosure) can be understood as design matters for a person skilled in the art based on the prior art in the relevant field. The present disclosure can be implemented based on the content disclosed in this specification and the common general technical knowledge in the relevant field. Furthermore, in this specification, the symbol "to" indicating a numerical range is used to mean that the numerical values ​​before and after it are included as the lower and upper limits. Furthermore, in this specification, a lower limit of "A or more" and an upper limit of "B or less" (A and B represent arbitrary numerical values) can be combined to form any numerical range. In the present disclosure, unless otherwise specified, the average particle size of particles is the median diameter (D50) value, which is the particle size at 50% of the cumulative value in the volume-based particle size distribution measured by laser diffraction / scattering particle size distribution measurement.

[0015] (1) First embodiment The present disclosure provides a battery having a positive electrode layer, an electrolyte layer, and a negative electrode layer, the positive electrode layer includes a positive electrode active material and an additive, The positive electrode active material contains an S element, the additive material contains a Cl element and at least one metal element selected from the group consisting of a Mn element, a Y element, a Sn element, a V element, a Nb element, and a Ta element; The battery is provided, wherein the proportion of the additive in the positive electrode layer is less than 10 mass %.

[0016] (2) Second embodiment The present disclosure provides a battery having a positive electrode layer, an electrolyte layer, and a negative electrode layer, the positive electrode layer includes a positive electrode active material and an additive, The positive electrode active material contains an S element, the additive material contains a Cl element and at least one metal element selected from the group consisting of an Mg element and an In element, The battery is provided, wherein the proportion of the additive in the positive electrode layer is 15 mass % or less.

[0017] In the present disclosure, a predetermined amount of an additive containing Cl and a predetermined metal element is added to a positive electrode layer containing a sulfur-based positive electrode active material containing sulfur. This improves the ion transport capacity in the positive electrode layer and improves the cycle characteristics of the battery. Furthermore, in the present disclosure, the discharge capacity of the battery can be improved under certain conditions.

[0018] The battery of the present disclosure has a positive electrode layer, an electrolyte layer, and a negative electrode layer, and typically has a positive electrode, an electrolyte layer, and a negative electrode. Fig. 1 is a schematic cross-sectional view illustrating a battery according to the present disclosure. The battery 10 shown in Fig. 1 includes a positive electrode layer 1, a negative electrode layer 2, an electrolyte layer 3 disposed between the positive electrode layer 1 and the negative electrode layer 2, a positive electrode current collector 4 that collects current from the positive electrode layer 1, and a negative electrode current collector 5 that collects current from the negative electrode layer 2.

[0019] [Positive electrode] The positive electrode has a positive electrode layer, and optionally further has a positive electrode current collector.

[0020] The positive electrode layer contains a positive electrode active material and an additive, and may further contain a sulfur-containing compound, a conductive material, a binder, and the like, as necessary. The thickness of the positive electrode layer may be, for example, 0.1 μm or more, 1 μm or more, or 30 μm or more, or 1000 μm or less, 500 μm or less, or 100 μm or less.

[0021] The positive electrode active material contains elemental sulfur. The positive electrode active material may be elemental sulfur, Li3PS4, or the like. An example of elemental sulfur is S8 sulfur. S8 sulfur can have three crystal forms: α sulfur (orthorhombic sulfur), β sulfur (monoclinic sulfur), and γ sulfur (monoclinic sulfur), and any of these crystal forms may be used. The positive electrode active material may be in the form of particles, which may be primary particles or secondary particles formed by aggregation of primary particles. The average particle size (D50) of the positive electrode active material is not particularly limited, but may be, for example, 0.01 μm or more, 0.5 μm or more, 50 μm or less, or 30 μm or less. The proportion of the positive electrode active material in the positive electrode layer may be, for example, 20% by mass or more, 30% by mass or more, 40% by mass or more, or 50% by mass or more. If the proportion of the positive electrode active material is too low, sufficient energy density may not be obtained. On the other hand, the proportion of the positive electrode active material in the positive electrode layer may be, for example, 80% by mass or less, 70% by mass or less, or 60% by mass or less. If the proportion of the positive electrode active material is too high, the ionic conductivity and electronic conductivity of the positive electrode layer may relatively decrease.

[0022] The additive may contain Cl element and at least one metal element selected from the group consisting of Mg element, In element, Mn element, Y element, Sn element, V element, Nb element, and Ta element. In the first embodiment, the metal element contained in the additional material is at least one element selected from the group consisting of Mn element, Y element, Sn element, V element, Nb element, and Ta element. In the second embodiment, the metal element contained in the additional material is at least one of Mg element and In element. The additive may be at least one metal chloride selected from the group consisting of MgCl2, InCl3, MnCl2, YCl3, SnCl2, VCl3, NbCl5, and TaCl5. In the first embodiment, the additive may be at least one metal chloride selected from the group consisting of MnCl2, YCl3, SnCl2, VCl3, NbCl5, and TaCl5. In the second embodiment, the additive may be at least one of MgCl2 and InCl3. The proportion of the additive in the positive electrode layer may be 15% by mass or less, 10% by mass or less, less than 10% by mass, 5% by mass or less, 3.5% by mass or less, 1% by mass or more, 1.5% by mass or more, or 2.5% by mass or more. When the metal element contained in the additive is at least one selected from the group consisting of Mn, Y, Sn, V, Nb, and Ta, the proportion of the additive in the positive electrode layer may be less than 10% by mass, may be 5% by mass or less, may be 3.5% by mass or less, may be 1% by mass or more, may be 1.5% by mass or more, or may be 2.5% by mass or more. When the metal element contained in the additive is at least one of Mg element and In element, the proportion of the additive in the positive electrode layer may be 15% by mass or less, 10% by mass or less, 5% by mass or less, 3.5% by mass or less, 1% by mass or more, 1.5% by mass or more, or 2.5% by mass or more.

[0023] The positive electrode layer may contain a sulfur-containing compound (first sulfur-containing compound) having P and S elements as the sulfur-containing compound. The positive electrode layer may further contain a sulfur-containing compound (second sulfur-containing compound) having an element other than P, such as Ge, Sn, Si, B, or Al, and S element. When the positive electrode layer further contains the second sulfur-containing compound, the positive electrode layer may contain the first sulfur-containing compound as the main component of the sulfur-containing compound. In the present disclosure, the term "main component" means that the first sulfur-containing compound accounts for 50% by mass or more of the total amount of the sulfur-containing compounds, where the total amount of the sulfur-containing compounds is 100% by mass. The first sulfur-containing compound may contain an ortho structure of the P element. Specifically, the ortho structure of the P element is a PS4 structure. The first sulfur-containing compound may be Li3PS4. The second sulfur-containing compound may contain an ortho structure of the M element (M is, for example, Ge, Sn, Si, B, or Al). Examples of the ortho structure of the M element include a GeS4 structure, a SnS4 structure, a SiS4 structure, a BS3 structure, and an AlS3 structure. On the other hand, the first sulfur-containing compound may contain a sulfide of the P element (for example, P2S5). The second sulfur-containing compound may contain a sulfide of the M element (M x S y ) where x and y are integers that provide electroneutrality with S depending on the type of M. Sulfides of M element (Mx S y ) include, for example, GeS2, SnS2, SiS2, B2S3, and Al2S3. These sulfides are, for example, residues of the starting materials. The proportion of the sulfur-containing compound in the positive electrode layer may be, for example, 1% by mass or more, 10% by mass or more, 20% by mass or more, 50% by mass or less, 30% by mass or less, 25.2% by mass or less, or 25% by mass or less.

[0024] The positive electrode layer may contain a conductive material. The addition of the conductive material improves the electronic conductivity of the positive electrode layer. Examples of the conductive material include carbon materials, metal particles, and conductive polymers. Examples of the carbon material include particulate carbon materials such as acetylene black (AB) and ketjen black (KB), and fibrous carbon materials such as vapor-grown carbon fiber (VGCF), carbon nanotubes (CNT), and carbon nanofibers (CNF). The proportion of the conductive material in the positive electrode layer may be, for example, 0.1% by mass or more, 0.5% by mass or more, or 1.0% by mass or more. If the proportion of the conductive material is too low, the electron conduction path in the positive electrode layer may be insufficient. On the other hand, the proportion of the conductive material in the positive electrode layer may be, for example, 30% by mass or less, 21.6% by mass or less, 5% by mass or less, or 3% by mass or less. If the proportion of the conductive material is too high, the proportion of the positive electrode active material may be relatively low, and the energy density of the positive electrode layer may be low.

[0025] The positive electrode layer may contain a binder, such as styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), butadiene rubber (BR), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), styrene-isoprene-styrene block copolymer (SIS), and ethylene-propylene-diene copolymer (EPDM). The proportion of the binder in the positive electrode layer may be, for example, 0.5% by mass or more. If the proportion of the binder is too low, it may be difficult to sufficiently reduce the increase in resistance due to charging and discharging of the battery. On the other hand, the proportion of the binder in the positive electrode layer may be, for example, 5% by mass or less. If the proportion of the binder is too high, the proportion of the positive electrode active material will be relatively low, which may result in a low energy density of the positive electrode layer.

[0026] The method for producing the positive electrode layer is not particularly limited, and examples thereof include a method in which a raw material mixture containing a positive electrode active material, an additive, a conductive material, and the like is mechanically milled to obtain a positive electrode composite, and the obtained positive electrode composite is pressed. Mechanical milling is not particularly limited as long as it is a method of mixing a raw material mixture while applying mechanical energy, and examples thereof include a ball mill, a vibration mill, a turbo mill, a mechanofusion mill, and a disk mill, and mechanical milling may particularly be a planetary ball mill. The mechanical milling may be dry mechanical milling or wet mechanical milling. The liquid used in wet mechanical milling may be aprotic to the extent that hydrogen sulfide is not generated, and specific examples include aprotic liquids such as polar aprotic liquids and nonpolar aprotic liquids. The mechanical milling conditions are appropriately set to obtain the desired positive electrode composite. For example, when using a planetary ball mill, the raw material mixture and milling balls are placed in a container and milled at a predetermined table rotation speed and for a predetermined time. The table rotation speed may be, for example, 200 rpm or more, 300 rpm or more, or 510 rpm or more. On the other hand, the table rotation speed may be, for example, 800 rpm or less or 600 rpm or less. The treatment time of the planetary ball mill may be, for example, 30 minutes or more, 4 hours or more, or 5 hours or more. On the other hand, the treatment time of the planetary ball mill may be, for example, 100 hours or less or 60 hours or less. Examples of materials for the container and milling balls used in the planetary ball mill include ZrO2 and Al2O3. The diameter of the milling balls is, for example, 1 mm or more and 20 mm or less. Mechanical milling may be performed in an inert gas atmosphere (e.g., an Ar gas atmosphere). The pressure during pressing is, for example, 0.1 ton / cm 2 It may be more than 0.5 ton / cm 2 It may be more than 1 ton / cm 2 On the other hand, the pressure during pressing may be, for example, 10 ton / cm 2 May be less than 8 ton / cm 2 It may be less than 6 ton / cm 2 It may be the following:

[0027] Examples of materials for the positive electrode current collector include SUS, Cr, Au, Pt, Zn, aluminum, copper, nickel, iron, titanium, and carbon. The thickness of the positive electrode current collector may be, for example, 0.1 μm or more and 100 μm or less. The positive electrode current collector may be in the form of a foil or a plate. The positive electrode current collector may have a buffer layer, an elastic layer, or a PTC (Positive Temperature Coefficient) thermistor layer disposed on its surface.

[0028] [Negative electrode] The negative electrode has a negative electrode layer, and optionally further has a negative electrode current collector.

[0029] The negative electrode layer contains a negative electrode active material, and may contain a conductive material, a binder, and the like, as necessary. Examples of the negative electrode active material include Li-based active materials. Examples of Li-based active materials include elemental Li and Li alloys, etc. Examples of metal elements other than lithium contained in Li alloys include Mg, Ag, In, Sn, Si, Ga, Au, and Pt. The conductive material and binder used in the negative electrode layer may be the same as those that can be contained in the positive electrode layer described above.

[0030] Examples of materials for the negative electrode current collector include SUS, aluminum, copper, nickel, iron, titanium, and carbon. The thickness of the negative electrode current collector may be, for example, within a range of 1 μm to 50 μm. The shape of the negative electrode current collector may be, for example, a foil or a plate. The negative electrode current collector may have a buffer layer, an elastic layer, or a PTC thermistor layer disposed on its surface.

[0031] [Electrolyte layer] The electrolyte layer is a layer formed between the positive electrode layer and the negative electrode layer and contains at least an electrolyte. The electrolyte may be a solid electrolyte. The electrolyte layer may be a solid electrolyte layer composed of a solid component including the solid electrolyte.

[0032] The solid electrolyte may be an inorganic solid electrolyte such as a sulfide solid electrolyte, a halide solid electrolyte, an oxide solid electrolyte, or a complex hydride solid electrolyte, or may be an organic solid electrolyte such as a gel electrolyte. Among these, the solid electrolyte may be a sulfide solid electrolyte from the viewpoint of increasing ion conductivity.

[0033] A sulfide solid electrolyte is an electrolyte containing S element as the main component of the anion component. A sulfide solid electrolyte usually contains at least Li element and S element. The sulfide solid electrolyte may further contain a Me element (Me is at least one of P, As, Sb, Si, Ge, Sn, B, Al, Ga, and In). Also, the sulfide solid electrolyte may contain halogen elements such as F, Cl, Br, and I.

[0034] The sulfide solid electrolyte may be a glassy (amorphous) sulfide solid electrolyte, a glass-ceramic sulfide solid electrolyte, or a crystalline sulfide solid electrolyte. The sulfide solid electrolyte may have a crystalline phase. Examples of the crystalline phase include, for example, Thio-LISICON type crystalline phase, argyrodite type crystalline phase, and LGPS type crystalline phase.

[0035] The composition of the sulfide solid electrolyte is not particularly limited, and examples thereof include, for example, xLi2S·(1-x)P2S5 (0.5≦x<1), and yLiI·zLiBr·(100-y-z)(xLi2S·(1-x)P2S5) (0.5≦x<1, 0≦y≦30, 0≦z≦30). In these compositions, x may satisfy 0.7≦x≦0.8. Also, as other examples of the composition of the sulfide solid electrolyte, Li 7-x PS 6-x X x is mentioned. X is at least one selected from the group consisting of F, Cl, Br, and I, and x satisfies 0≦x<2. Also, as other examples of the composition of the sulfide solid electrolyte, Li 4-x Mq 1-x P x S4 (0<x<1) is mentioned. Mq is at least one of Al, Zn, In, Ge, Si, Sn, Sb, Ga, and Bi. Examples of the sulfide solid electrolyte include Li6PS5Cl, LiI-LiBr-Li2S-P2S5, LiI-Li2S-P2S5, LiI-Li2S-P2O5, and LiI-Li3PO4-P2S5.

[0036] Examples of oxide solid electrolytes include substances having a garnet-type crystal structure containing Li, La, A (A is at least one of Zr, Nb, Ta, and Al), and O. Examples of oxide solid electrolytes include Li2O-B2O3-P2O5, Li2O-SiO2, Li2O-B2O3, Li 1.3 Al 0.3 Ti 0.7 (PO4)3, Li5La3Ta2O 12 , Li7La3Zr2O 12 , Li6BaLa2Ta2O 12 , Li 3.6 Si 0.6 P 0.4 O4, Li4SiO4, Li3PO4, and Li 3+x PO 4-x N x (1≦x≦3) etc. may also be used.

[0037] The halide solid electrolyte may be, for example, a solid electrolyte containing Li, D, and X (D represents at least one of Ti, Al, and Y, and X represents F, Cl, or Br).

[0038] The solid electrolyte may be in the form of particles from the viewpoint of ease of handling. The average particle size (D50) of the solid electrolyte particles is not particularly limited and may be from 1 nm to 100 μm. The solid electrolyte may be used alone or in combination of two or more. When two or more solid electrolytes are used, the two or more solid electrolytes may be mixed, or two or more solid electrolyte layers may be formed to form a multilayer structure. The proportion of the solid electrolyte in the electrolyte layer is not particularly limited, but may be, for example, 50% by mass or more, 60% by mass or more, 70% by mass or more, or 100% by mass. The electrolyte layer may contain less than 10% by mass of electrolytic solution relative to the total amount of the electrolyte layer. The solid electrolyte may be a composite solid electrolyte containing an inorganic solid electrolyte and a polymer electrolyte. When the electrolyte layer is a solid electrolyte layer, the solid electrolyte layer contains a solid electrolyte and, if necessary, a binder and the like. Examples of the binder include the binders that can be contained in the positive electrode layer described above. When the solid electrolyte layer contains a binder, the content of the binder may be 0% by mass to 10% by mass with respect to the total amount of the solid electrolyte layer. The thickness of the electrolyte layer may be, for example, 0.1 μm or more, 1000 μm or less, 500 μm or less, or 100 μm or less.

[0039] The battery of the present disclosure may further include a constraining jig that applies a constraining pressure to the positive electrode layer, the electrolyte layer, and the negative electrode layer in the thickness direction. In particular, when the electrolyte layer is a solid electrolyte layer, the constraining pressure may be applied to form good ion conduction paths and electron conduction paths. The constraining pressure may be, for example, 0.1 MPa or more, 1 MPa or more, or 5 MPa or more. Meanwhile, the constraining pressure may be, for example, 100 MPa or less, 50 MPa or less, or 20 MPa or less.

[0040] The type of battery in the present disclosure is not particularly limited, but is typically a lithium-ion battery. Furthermore, the battery in the present disclosure may be a liquid battery whose electrolyte layer contains an electrolytic solution, or a solid battery whose electrolyte layer contains a solid electrolyte. The solid battery may be a semi-solid battery or an all-solid-state battery. In the present disclosure, a semi-solid battery is a battery whose electrolyte layer has a solid component such as a solid electrolyte and a liquid component (e.g., an ionic liquid). In the present disclosure, an all-solid-state battery is a battery whose electrolyte layer has only a solid component such as a solid electrolyte. Furthermore, the battery in the present disclosure may be a primary battery or a secondary battery, but a secondary battery is particularly preferred. This is because it can be repeatedly charged and discharged and is useful, for example, as an on-board battery. The shape of the battery is not particularly limited, and may be, for example, a coin type, a cylindrical type, a square type, a sheet type, a button type, a flat type, or a laminate type.

[0041] Examples of uses of the battery include power sources for vehicles such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), electric vehicles (BEVs), gasoline-powered vehicles, and diesel-powered vehicles. In particular, the battery may be used as a driving power source for hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), or electric vehicles (BEVs). The battery may also be used as a power source for mobile objects other than vehicles (e.g., trains, ships, and aircraft), and as a power source for electrical appliances such as information processing devices.

[0042] The present disclosure is not limited to the above-described embodiments. The above-described embodiments are merely examples, and any configuration that is substantially identical to the technical idea described in the claims of the present disclosure and that provides similar effects is included within the technical scope of the present disclosure. [Example]

[0043] [Examples 1 and 2, Comparative Examples 1 and 2] (Positive electrode composite production) Elemental sulfur (S) (positive electrode active material), Li3PS4 (sulfur-containing compound), and Ketjen black (conductive material; hereinafter sometimes referred to as C) were weighed out in a mass ratio of 53.2:25.2:21.6. The metal chloride VCl3 was then weighed out so that its content relative to the total mass of the positive electrode layer was 0% by mass (Comparative Example 1), 2.5% by mass (Example 1), 5% by mass (Example 2), or 10% by mass (Comparative Example 2). In each example, these were mixed to obtain a mixture of S-Li3PS4-C-VCl3. In each example, 0.2 g of the S-Li3PS4-C-VCl3 mixture and 30 g of φ5 mm zirconia balls were placed in a planetary ball mill pot, and mechanical milling was performed using the planetary ball mill at 600 rpm for a total of 4 hours to obtain a positive electrode composite. (Cell preparation) Using the prepared positive electrode composite, a φ10 mm cell was fabricated according to the following procedure. A sulfide solid electrolyte (Li6PS5Cl) was placed in a container and pressed at 100 MPa to create a solid electrolyte layer. The positive electrode composite was placed on one side of the solid electrolyte layer in the container and pressed at 300 MPa to create a positive electrode layer on one side of the solid electrolyte layer. Next, In foil (9 mm diameter) and Li foil (6 mm diameter) were placed in the container in this order as the raw materials for the negative electrode layer on the side of the solid electrolyte layer opposite the positive electrode layer. Then, SUS foil was placed on the positive electrode layer side as a positive electrode current collector, and SUS foil was placed on the negative electrode layer side as a negative electrode current collector, to obtain a laminate. A confining pressure of 10 N·m (equivalent to 60 MPa) was applied to the resulting laminate. 1C=2.55mA / cm 2 As a result, the current density is 0.255mA / cm 2 (equivalent to 0.1C), and as conditioning, a voltage of 0.8V vs Li-In (1.42V vs Li / Li + ) The In foil and Li foil were then alloyed to obtain a Li-In alloy as the anode layer, and an all-solid-state battery was fabricated comprising a cathode current collector, a cathode layer, a solid electrolyte layer, an anode layer, and an anode current collector.

[0044] [Examples 3 to 4, Comparative Example 3] All-solid-state batteries were produced in the same manner as in Example 1, except that in the above (preparation of positive electrode composite), NbCl was used as the metal chloride instead of VCl, and the metal chloride was weighed so that the content of NbCl was 2.5 mass % (Example 3), 5 mass % (Example 4), and 10 mass % (Comparative Example 3) relative to the total mass of the positive electrode layer.

[0045] [Examples 5 to 6, Comparative Example 4] All-solid-state batteries were produced in the same manner as in Example 1, except that in the above (preparation of positive electrode composite), TaCl was used instead of VCl as the metal chloride, and the metal chloride was weighed so that the content of TaCl was 2.5 mass % (Example 5), 5 mass % (Example 6), and 10 mass % (Comparative Example 4) relative to the total mass of the positive electrode layer.

[0046] [Examples 7 to 11] All-solid-state batteries were produced in the same manner as in Example 1, except that in the above (preparation of positive electrode composite), MgCl was used instead of VCl as the metal chloride, and the metal chloride was weighed out so that the content of MgCl was 1.5 mass % (Example 7), 2.5 mass % (Example 8), 3.5 mass % (Example 9), 5 mass % (Example 10), or 10 mass % (Example 11) relative to the total mass of the positive electrode layer.

[0047] Comparative Example 5 An all-solid-state battery was produced in the same manner as in Example 1, except that in the above (preparation of positive electrode composite), SiCl was used as the metal chloride instead of VCl, and the metal chloride was weighed so that the content of SiCl was 2.5 mass % (Comparative Example 5) relative to the total mass of the positive electrode layer.

[0048] [Example 12] An all-solid-state battery was produced in the same manner as in Example 1, except that in the above (preparation of positive electrode composite), MnCl was used as the metal chloride instead of VCl, and the metal chloride was weighed so that the content of MnCl was 2.5 mass % (Example 12) relative to the total mass of the positive electrode layer.

[0049] Comparative Example 6 An all-solid-state battery was produced in the same manner as in Example 1, except that in the above (preparation of positive electrode composite), FeCl was used as the metal chloride instead of VCl, and the metal chloride was weighed so that the content of FeCl was 2.5 mass% (Comparative Example 6) relative to the total mass of the positive electrode layer.

[0050] [Example 13] An all-solid-state battery was produced in the same manner as in Example 1, except that in the above (preparation of positive electrode composite), YCl was used instead of VCl as the metal chloride, and the metal chloride was weighed so that the content of YCl was 2.5 mass % (Example 13) relative to the total mass of the positive electrode layer.

[0051] [Examples 14 to 16] All-solid-state batteries were produced in the same manner as in Example 1, except that in the above (preparation of positive electrode composite), InCl was used instead of VCl as the metal chloride, and the metal chloride was weighed so that the content of InCl was 2.5 mass % (Example 14), 5 mass % (Example 15), or 10 mass % (Example 16) relative to the total mass of the positive electrode layer.

[0052] [Example 17] An all-solid-state battery was produced in the same manner as in Example 1, except that in the above (preparation of positive electrode composite), SnCl was used as the metal chloride instead of VCl, and the metal chloride was weighed so that the content of SnCl was 2.5 mass% (Example 17) relative to the total mass of the positive electrode layer.

[0053] (Electrochemical measurements) For the all-solid-state batteries prepared in Examples 1 to 17 and Comparative Examples 1 to 6, the cutoff voltage was 2.7 V - 0.8 V vs. Li-In (3.32 V - 1.42 V vs. Li / Li + ) and constant current charge / discharge tests were carried out at 25°C. Table 1 shows the measurement results of the discharge capacity (mAh / gS-Li3PS4-C) for the all-solid-state batteries fabricated in Examples 1 to 6 and Comparative Examples 1 to 4 at the initial time and after 20 cycles, based on the mass of the positive electrode layer excluding the mass of the additive. Table 2 shows the measurement results of the discharge capacity (mAh / g-cathode) for the first and after 20 cycles for the all-solid-state batteries fabricated in Examples 1 and 2 and Comparative Examples 1 and 2, based on the mass of the positive electrode layer including the mass of the additive (VCl3). Table 3 shows the measurement results of the discharge capacity (mAh / gS-Li3PS4-C) for the first time and after 10 cycles for the all-solid-state batteries fabricated in Examples 7 to 17 and Comparative Examples 1, 5, and 6, based on the mass of the positive electrode layer excluding the mass of the additive. The initial discharge capacity is the discharge capacity at the time of the initial discharge of the all-solid-state battery obtained after conditioning the laminate. The discharge capacity (mAh / gS-LiPS-C) of the all-solid-state battery based on the mass of the positive electrode layer excluding the mass of the additive is used to compare the utilization rate of the positive electrode active material in the positive electrode layer with that of Comparative Example 1, which does not contain the additive. The discharge capacity (mAh / g-cathode) of an all-solid-state battery based on the mass of the positive electrode layer, including the mass of additives, is the discharge capacity taking into account the energy density of the positive electrode layer.

[0054] [Table 1]

[0055] [Table 2]

[0056] [Table 3]

[0057] (Evaluation results) Fig. 2 is a graph showing the relationship between the number of charge / discharge cycles and the discharge capacity based on the mass of the positive electrode layer excluding the mass of the additive for an all-solid-state battery in which the additive is VCl3. Fig. 2 shows the results for the additive content of 0 mass%, 2.5 mass%, 5 mass%, and 10 mass%. Fig. 3 is a graph showing the relationship between the number of charge / discharge cycles and the discharge capacity based on the mass of the positive electrode layer excluding the mass of the additive for an all-solid-state battery in which the additive is NbCl5. Fig. 3 shows the results when the content of the additive is 0 mass%, 5 mass%, and 10 mass%. Fig. 4 is a graph showing the relationship between the number of charge / discharge cycles and the discharge capacity based on the mass of the positive electrode layer excluding the mass of the additive for an all-solid-state battery in which the additive is TaCl5. Fig. 4 shows the results when the content of the additive is 0 mass%, 5 mass%, 10 mass%, and 20 mass%. Fig. 5 is a graph showing the relationship between the number of charge / discharge cycles and the discharge capacity based on the mass of the positive electrode layer, including the mass of the additive, of an all-solid-state battery in which the additive is VCl3. Fig. 5 shows the results when the additive content is 0 mass%, 2.5 mass%, 5 mass%, and 10 mass%.

[0058] (Comparison of discharge capacity of all-solid-state batteries based on the mass of the positive electrode layer excluding the mass of additives) As shown in Examples 1 to 6 in Table 1, when the additives were VCl3, NbCl5, and TaCl5, the discharge capacities (mAh / gS-Li3PS4-C) at the initial stage and after 20 cycles, based on the mass of the positive electrode layer excluding the mass of the additives, were both higher than those of Comparative Example 1, which contained no additives, and the discharge capacity and cycle characteristics of the all-solid-state battery were excellent. This is thought to be because the addition of metal chlorides improves the Li-ion transport capacity in the positive electrode layer, increasing the utilization rate of the positive electrode active material. Furthermore, as shown in Examples 7 to 17 in Table 3, when the additives were MgCl2, InCl3, MnCl2, YCl3, and SnCl2, the discharge capacities (mAh / gS-Li3PS4-C) at the initial stage and after 10 cycles based on the mass of the positive electrode layer excluding the mass of the additives were both greater than those of Comparative Example 1, which did not contain any additives, and the discharge capacity and cycle characteristics of the all-solid-state battery were excellent. On the other hand, as shown in Comparative Examples 2 to 4 in Table 1, when the content of VCl3, NbCl5, and TaCl5 is 10 mass %, the discharge capacity after the first cycle and after 20 cycles is equal to or decreases compared to Comparative Example 1 with no additives added. This is thought to be because if the content of the additives is too high, the charge-discharge reaction of the positive electrode active material is inhibited. On the other hand, as shown in Examples 11 and 16 in Table 3, when the additives are MgCl2 and InCl3, even when the content of the additives is 10 mass%, the discharge capacities at the initial stage and after 10 cycles are both greater than those of Comparative Example 1 in which no additives are added, and the discharge capacity and cycle characteristics of the all-solid-state battery are excellent. Furthermore, as shown in Comparative Examples 5 and 6 in Table 3, when the additives are SiCl4 and FeCl2, even if the content of the additives is 2.5 mass%, the discharge capacity at the initial stage and after 10 cycles is both lower than that of Comparative Example 1, which does not contain any additives. From the above, it can be seen that when the additive is at least one metal chloride selected from the group consisting of MgCl2, InCl3, MnCl2, YCl3, SnCl2, VCl3, NbCl5, and TaCl5, as long as the content of the additive is at least less than 10 mass%, the discharge capacity (mAh / gS-Li3PS4-C) based on the mass of the positive electrode layer excluding the mass of the additive is increased compared to Comparative Example 1 where no additive is added. Also, it can be seen that when the additive is at least one of MgCl2 and InCl3, even if the content of the additive is 10 mass%, the discharge capacity (mAh / gS-Li3PS4-C) based on the mass of the positive electrode layer excluding the mass of the additive is increased compared to Comparative Example 1 where no additive is added.

[0059] (Comparison of discharge capacity of all-solid-state batteries based on the mass of the positive electrode layer, including the mass of additives) As shown in Examples 1 and 2 in Table 2, when the additive is VCl3 and the content of the additive is 2.5 mass % or 5 mass %, the discharge capacity after 20 cycles (mAh / g-cathode) of the all-solid-state battery based on the mass of the positive electrode layer including the mass of the additive is greater than that of Comparative Example 1 in which no additive is added, and the discharge capacity after 20 cycles and the cycle characteristics of the all-solid-state battery are excellent. This result is thought to be due to the fact that within the above range of additive content, the effect of increasing the utilization rate of the positive electrode active material by the additive outweighs the increase in mass of the positive electrode layer due to the increase in additive content. [Explanation of symbols]

[0060] 1...Positive electrode layer 2...Anode layer 3...electrolyte layer 4...Positive electrode current collector 5...Negative electrode current collector 10...battery

Claims

1. A battery having a positive electrode layer, an electrolyte layer, and a negative electrode layer, the positive electrode layer includes a positive electrode active material and an additive, The positive electrode active material contains an S element, the additive material includes Cl element and at least one metal element selected from the group consisting of Mn element, Y element, Sn element, V element, Nb element, and Ta element, and the proportion of the additive material in the positive electrode layer is less than 10 mass%.

2. A battery having a positive electrode layer, an electrolyte layer, and a negative electrode layer, the positive electrode layer includes a positive electrode active material and an additive, The positive electrode active material contains an S element, the additive material includes a Cl element and at least one metal element selected from the group consisting of an Mg element and an In element; The battery, wherein the proportion of the additive in the positive electrode layer is 15 mass % or less.

3. The battery according to claim 1 or 2, wherein the content of the additive in the positive electrode layer is 1% by mass or more and 5% by mass or less.

4. the negative electrode layer contains a negative electrode active material, 3. The battery according to claim 1, wherein the negative electrode active material is at least one of simple Li and a Li alloy.

5. 3. The all-solid-state battery according to claim 1, wherein the electrolyte layer is a solid electrolyte layer containing a solid electrolyte.

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