All-solid-state batteries

Abstract

To provide an all-solid battery capable of suppressing such a reaction that an inner surface of a metal container is reduced by a halide-based solid electrolyte, thereby preventing reduction in capacity retention caused by deterioration of the inner surface of the metal container.SOLUTION: In an all-solid battery 100, at least one of a positive electrode 10, a negative electrode 20, and a solid electrolyte layer 30 contains a halide-based solid electrolyte. An inner surface of a metal container 40 is at least partially coated with a coating layer 50. The coating layer 50 contains at least one or more kinds of metals selected from aluminum, nickel, titanium, and zirconium.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to an all-solid-state battery. [Background technology]

[0002] Traditionally, solid electrolytes used in all-solid-state batteries have included oxide-based, sulfide-based, and hydride-based types. In recent years, development of halide-based solid electrolytes such as Li2ZrCl6 and Li3ZrCl6 has been progressing.

[0003] Furthermore, some metal containers that house the power generation elements of all-solid-state batteries have a coating layer formed on their inner surface. For example, Patent Document 1 describes an all-solid-state battery in which a power generation element, including a positive electrode, a negative electrode, and a solid electrolyte layer interposed between the positive and negative electrodes, is housed inside a metal container. In the power generation element described in Patent Document 1, at least one of the positive electrode, negative electrode, and solid electrolyte layer contains a sulfide-based solid electrolyte. Patent Document 1 describes a metal container in which a gold or platinum coating layer is formed on the inner surface. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2021-012835 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] However, in all-solid-state batteries where the power generation element containing a halide-based solid electrolyte is housed in a metal container, a problem has arisen because the inner surface of the metal container comes into contact with the halide-based solid electrolyte, leading to a reduction and degradation of the inner surface of the metal container. This reduction and degradation of the inner surface of the metal container is an irreversible reaction, and as this reaction progresses, the halide-based solid electrolyte in the power generation element is oxidized, reducing the capacity of the all-solid-state battery.

[0006] The present invention has been made in view of the above problems, and aims to provide an all-solid-state battery that can suppress the reaction in which the inner surface of the metal container is reduced by a halide-based solid electrolyte, and can prevent a decrease in capacity retention rate due to deterioration of the inner surface of the metal container. [Means for solving the problem]

[0007] In order to solve the above problems, the inventors focused on metal materials that are less likely to be reduced even when in contact with halide-based solid electrolytes and conducted extensive research. As a result, we discovered that the inner surface of a metal container can be coated with a coating layer containing at least one metal selected from aluminum, nickel, titanium, and zirconium, an alloy containing the said metal, or an oxide containing the said metal, and thus conceived the present invention. In other words, the present invention relates to the following invention.

[0008] [1] A power generation element comprising a positive electrode, a negative electrode, and a solid electrolyte layer interposed between the positive electrode and the negative electrode, It has a metal container that houses the power generation element, At least one of the positive electrode, the negative electrode, and the solid electrolyte layer contains a halide-based solid electrolyte represented by the following formula (1): At least a portion of the inner surface of the metal container is covered with a coating layer. An all-solid-state battery characterized in that the coating layer comprises at least one metal selected from aluminum, nickel, titanium, and zirconium, an alloy containing the metal, and an oxide containing the metal. LiaEbGcXd···(1) (In formula (1), E is at least one element selected from the group consisting of Al, Sc, Y, Zr, Hf, and lanthanides. G is OH, BO2, BO3, BO4, B3O6, B4O7, CO3, NO3, AlO2, SiO3, SiO4, Si2O7, Si3O9, Si4O 11 Si6O 18, PO3, PO4, P2O7, P3O 10 , SO3, SO4, SO5, S2O3, S2O4, S2O5, S2O6, S2O7, S2O8, BF4, PF6, BOB, (COO)2, N, AlCl4, CF3SO3, CH3COO, CF3COO, O, and is at least one group selected from the group consisting of. X is at least one element selected from the group consisting of F, Cl, Br, and I. 0.5 ≦ a < 6, 0 < b < 2, 0 ≦ c ≦ 6, 0 < d ≦ 6.1.)

[0009] [2] The all-solid-state battery according to [1], wherein 90% or more of the surface area of the inner surface is covered with the coating layer. [3] The all-solid-state battery according to [1] or [2], wherein the thickness of the coating layer is 0.05 μm or more.

[0010] [4] The negative electrode is Li + / The all-solid-state battery according to any one of [1] to [3], including a negative electrode active material having an electrode potential in a range of 0.5 V or more based on the Li equilibrium potential. [5] The all-solid-state battery according to [4], wherein the negative electrode active material contains a titanium oxide. [6] The all-solid-state battery according to [5], wherein the titanium oxide is lithium titanate.

[0011] [7] The all-solid-state battery according to any one of [1] to [6], wherein a current collector layer is disposed between the inner surface of the metal container and the negative electrode. [Advantages of the Invention]

[0012] In the all-solid-state battery of the present invention, at least one of the positive electrode, negative electrode, and solid electrolyte layer contains a halide-based solid electrolyte represented by formula (1), at least a part of the inner surface of the metal container is covered with a coating layer, and the coating layer contains at least one selected from at least one metal selected from aluminum, nickel, titanium, and zirconium, an alloy containing the metal, and an oxide containing the metal. Therefore, it is possible to suppress the reaction in which the inner surface of the metal container is reduced by the halide-based solid electrolyte, and it becomes an all-solid-state battery that can prevent a decrease in the capacity retention rate due to deterioration of the inner surface of the metal container. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 is a schematic cross-sectional view showing an all-solid-state battery according to the first embodiment. [Figure 2] Figure 2 is a schematic cross-sectional view showing an all-solid-state battery according to the second embodiment. [Modes for carrying out the invention]

[0014] The all-solid-state battery of this embodiment will be described in detail below, with appropriate reference to the drawings. The drawings used in the following description may be enlarged for convenience in order to clearly illustrate the features of the present invention. Therefore, the dimensional ratios of each component may differ from those of the actual components. The materials, dimensions, etc., exemplified in the following description are examples only, and the present invention is not limited to them. It can be implemented with appropriate modifications without changing the essence of the invention.

[0015] <First Embodiment> [All-solid battery] Figure 1 is a schematic cross-sectional view showing a solid-state battery of the first embodiment. The solid-state battery 100 shown in Figure 1 has a power generation element 70 and a metal container 40 that houses the power generation element 70. The shape of the solid-state battery 100 is, for example, a flat shape such as a coin type or a button type.

[0016] (metal container) The metal container 40 is cylindrical. The planar shape of the metal container 40 may be polygonal (for example, triangular, quadrilateral, pentagonal, hexagonal, heptagonal, or octagonal), circular, or elliptical. The metal container 40 has a first container 41 and a second container 42. As shown in Figure 1, the first container 41 and the second container 42 are arranged with the power generation element 70 in the thickness direction of the power generation element 70 (the stacking direction of the positive electrode 10, the negative electrode 20, and the solid electrolyte layer 30), with the power generation element 70 in between.

[0017] The edges of the first container 41 and the second container 42 are fitted together via a gasket 60. The inside of the metal container 40 is sealed by the gasket 60, making it airtight. For example, the gasket 60 can be made of polypropylene, nylon, or the like. If heat resistance is required for the gasket 60 depending on the application of the all-solid-state battery 100, it is preferable to use a heat-resistant resin as the material for the gasket 60. Examples of heat-resistant resins that can be used as the material for the gasket 60 include fluororesins such as tetrafluoroethylene-perfluoroalkoxyethylene copolymer (PFA), polyphenylene ether (PEE), polysulfone (PSF), polyarylate (PAR), polyethersulfone (PES), polyphenylene sulfide (PPS), and polyetheretherketone (PEEK), and it is preferable to use a heat-resistant resin with a melting point exceeding 240°C. Furthermore, when the all-solid-state battery 100 is used in applications requiring heat resistance, known materials such as glass hermetic seals can be used as the material for the gasket 60.

[0018] The first container 41 and the second container 42 are conductors made of metal. The first container 41 also serves as the positive electrode terminal. As shown in Figure 1, the positive electrode 10 of the power generation element 70 is placed in contact with the inner surface of the first container 41, thereby electrically connecting the first container 41 and the positive electrode 10. The second container 42 also serves as the negative electrode terminal. As shown in Figure 1, the negative electrode 20 of the power generation element 70 is placed in contact with the inner surface of the second container 42, thereby electrically connecting the second container 42 and the negative electrode 20.

[0019] The metals forming the first container 41 and the second container 42 can be, for example, stainless steel, copper, nickel, or aluminum, but stainless steel is preferred because it is strong and inexpensive. The first container 41 and the second container 42 may be formed from the same material or from different materials.

[0020] The first container 41 and the second container 42 have at least a portion of their inner surface coated with a coating layer 50. The coating layer 50 contains at least one metal selected from aluminum, nickel, titanium, and zirconium, an alloy containing the said metal, and an oxide containing the said metal. Examples of alloys containing the said metal include AlCu, AlMn, AlZr, NiCu, NiCr, NiFe, TiAlSn, and TiPd. Examples of oxides containing the said metal include aluminum oxide and titanium oxide.

[0021] The coating layer 50 is less susceptible to reduction by the halide-based solid electrolyte and can more effectively prevent a decrease in capacity retention due to deterioration of the inner surface of the metal container 40. Therefore, it is preferable that the coating layer 50 be made of at least one metal selected from aluminum, nickel, titanium, and zirconium, and more preferably aluminum or nickel. It is particularly preferable that the coating layer 50 be made of aluminum, which has a low specific gravity and is a light material, because it can contribute to improving the energy density of the all-solid-state battery 100.

[0022] The coating layer 50 preferably consists of only at least one selected from the metal, the alloy containing the metal, and the oxide containing the metal. In addition to at least one selected from the metal, the alloy containing the metal, and the oxide containing the metal, the coating layer 50 may also contain, for example, gold, platinum, etc., to the extent that the effects of this embodiment can be obtained. Even when the coating layer 50 contains gold and / or platinum, the reaction in which the inner surface of the metal container 40 is reduced by the halide-based solid electrolyte can be suppressed. When the coating layer 50 contains gold and / or platinum, the amount of gold and / or platinum is preferably within a range that does not impair the energy density of the all-solid-state battery 100.

[0023] In order to more effectively prevent a decrease in capacity retention rate due to deterioration of the inner surface of the metal container 40, it is preferable that 50% or more of the inner surface area of ​​the first container 41 and the second container 42 is covered with the coating layer 50, more preferably 90% or more of the inner surface area is covered with the coating layer 50, and most preferably, as shown in Figure 1, the entire inner surface is covered with the coating layer 50. The proportion of the inner surface area covered with the coating layer 50 may be the same for the first container 41 and the second container 42, or it may be different for each.

[0024] When only a portion of the inner surface of the first container 41 is covered with the coating layer 50, it is preferable that the area covered with the coating layer 50 includes, for example, the area where the inner surface of the first container 41 and the positive electrode 10 of the power generation element 70 are in contact. When only a portion of the inner surface of the second container 42 is covered with the coating layer 50, it is preferable that the area covered with the coating layer 50 includes, for example, the area where the inner surface of the second container 42 and the negative electrode 20 of the power generation element 70 are in contact.

[0025] The coating layer 50 only needs to be formed on at least a portion of the inner surface of the metal container 40. As shown in Figure 1, it may be formed only on the inner surface of the metal container 40, or it may be formed not only on the inner surface of the metal container 40 but also on a portion or the entire outer surface.

[0026] The thickness of the coating layer 50 is preferably 0.05 μm or more. When the thickness of the coating layer 50 is 0.05 μm or more, the decrease in the capacity retention rate due to deterioration of the inner surface of the metal container 40 can be prevented more effectively. The thickness of the coating layer 50 is more preferably 0.07 μm or more, and even more preferably 0.08 μm or more. The effect of suppressing the decrease in the capacity retention rate due to deterioration of the inner surface of the metal container 40 does not improve even if the thickness of the coating layer 50 exceeds 0.10 μm. Therefore, the thickness of the coating layer 50 is preferably 0.10 μm or less.

[0027] The thickness of the coating layer 50 can be measured using an X-ray fluorescence analyzer by the following method. Specifically, the thickness can be measured using an X-ray fluorescence analyzer at five points: an arbitrary point on the inner surface of the first container 41 and the second container 42 coated with the coating layer 50, and four points on a line perpendicular to that point and equally spaced from that point. The average value of these measurements can then be calculated. The thickness of the coating layer 50 may be measured by cutting the first container 41 and the second container 42 and observing the cut surfaces using a microscope, or by using the beta-ray test method.

[0028] The coating layer 50 can be formed by known methods such as electroplating or sputtering. When forming the coating layer 50 on only a portion of the inner surface of the first container 41 and / or the second container 42, the coating layer 50 can be formed by, for example, using a known mask depending on the method of forming the coating layer 50. Specifically, a mask can be applied to the area of ​​the inner surface of the first container 41 and / or the second container 42 where the coating layer 50 is not to be formed, using a known method, before forming the coating layer 50, and then the mask can be removed.

[0029] (Power generation element) As shown in Figure 1, the power generation element 70 includes a positive electrode 10, a negative electrode 20, and a solid electrolyte layer 30 interposed between the positive electrode 10 and the negative electrode 20. The planar shape of the solid electrolyte layer 30 may be a polygon (for example, a triangle, square, pentagon, hexagon, heptagon, or octagon), or it may be circular or elliptical, and can be determined according to the planar shape of the metal container 40, and may be similar in shape to the planar shape of the metal container 40.

[0030] In the all-solid-state battery 100 of this embodiment, the positive electrode 10, the negative electrode 20, and the solid electrolyte layer 30 all contain a halide-based solid electrolyte represented by formula (1). The halide-based solid electrolyte represented by formula (1) contained in the power generation element 70 improves the ionic conductivity within the power generation element 70. The halide-based solid electrolytes represented by formula (1) contained in the positive electrode 10, the negative electrode 20, and the solid electrolyte layer 30 may each have different compositions, or they may have the same composition in part or in whole.

[0031] LiaEbGcXd···(1) (In formula (1), E is at least one element selected from the group consisting of Al, Sc, Y, Zr, Hf, and lanthanides. G is OH, BO2, BO3, BO4, B3O6, B4O7, CO3, NO3, AlO2, SiO3, SiO4, Si2O7, Si3O9, Si4O 11 Si6O 18 PO3, PO4, P2O7, P3O 10 , is at least one group selected from the group consisting of SO3, SO4, SO5, S2O3, S2O4, S2O5, S2O6, S2O7, S2O8, BF4, PF6, BOB, (COO)2, N, AlCl4, CF3SO3, CH3COO, CF3COO, O. X is at least one element selected from the group consisting of F, Cl, Br, I. 0.5≦a<6, 0 <b<2、0≦c≦6、0<d≦6.1である。)

[0032] The halide-based solid electrolyte represented by formula (1) has good ionic conductivity. Therefore, the all-solid-state battery 100 of this embodiment has a high discharge capacity. Furthermore, the halide-based solid electrolyte represented by formula (1) does not react with water or other substances to generate hydrogen sulfide gas, unlike sulfide-based solid electrolytes, for example, and hydrogen sulfide gas does not degrade the all-solid-state battery 100, thus providing excellent reliability.

[0033] In the halide solid electrolyte represented by formula (1), Li is an essential element. In formula (1), a is in the range of 0.5 or more and less than 6. In the halide-based solid electrolyte represented by formula (1), E is an essential element. E is at least one element selected from the group consisting of Al, Sc, Y, Zr, Hf, and lanthanoids. Among these, E is preferably Zr because it results in a halide-based solid electrolyte that can provide a all-solid-state battery 100 with even higher ionic conductivity. In formula (1), b is in the range greater than 0 and less than 2.

[0034] In the halide-based solid electrolyte represented by formula (1), G is an optionally contained element. G is at least one group selected from the group consisting of OH, BO2, BO3, BO4, B3O6, B4O7, CO3, NO3, AlO2, SiO3, SiO4, Si2O7, Si3O9, Si4O 11 , Si6O 18 , PO3, PO4, P2O7, P3O 10 , SO3, SO4, SO5, S2O3, S2O4, S2O5, S2O6, S2O7, S2O8, BF4, PF6, BOB, (COO)2, N, AlCl4, CF3SO3, CH3COO, CF3COO, O. Among these, G is preferably SO4 because it results in a halide-based solid electrolyte that can provide a all-solid-state battery 100 with good stability on the reduction potential side. In formula (1), c is in the range of 0 to 6.

[0035] In the halide-based solid electrolyte represented by formula (1), X is an essential element. X is at least one element selected from the group consisting of F, Cl, Br, and I. Among these, X is preferably Cl because it results in a halide-based solid electrolyte that can provide a all-solid-state battery 100 with even higher ionic conductivity. In formula (1), d is in the range greater than 0 and less than or equal to 6.1. a, b, c, and d in formula (1) are appropriately determined within the above ranges according to the types of elements represented by A, E, G, and X in formula (1).

[0036] Examples of halide-based solid electrolytes represented by formula (1) include Li2ZrCl6, Li2ZrSO4Cl4, Li2ZrF6, Li2ZrBr6, Li2ZrI6, Li2ZrSO4F4, Li2ZrSO4Br4, Li2ZrSO4I4, and Li2ZrCl5CH3COO. Among these, Li2ZrCl6 or Li2ZrSO4Cl4 are particularly preferred as the halide-based solid electrolyte. This is because it allows for the creation of an all-solid-state battery 100 with high ionic conductivity and good stability on the reduction potential side.

[0037] "Positive electrode" The positive electrode 10 includes a positive electrode active material and a halide-based solid electrolyte represented by formula (1). The positive electrode 10 may contain, as the solid electrolyte, not only the halide-based solid electrolyte represented by formula (1), but also a solid electrolyte other than the halide-based solid electrolyte represented by formula (1). Examples of other solid electrolytes include known solid electrolytes such as oxide-based solid electrolytes, sulfide-based solid electrolytes, and hydride-based solid electrolytes.

[0038] The content of the halide-based solid electrolyte represented by formula (1) in the positive electrode 10 can be, for example, 10% to 70% by mass, and preferably 10% to 40% by mass. When the content of the halide-based solid electrolyte represented by formula (1) is 10% by mass or more, the effect of improving the ionic conductivity within the positive electrode 10 due to the inclusion of the halide-based solid electrolyte represented by formula (1) becomes significant. When the content of the halide-based solid electrolyte represented by formula (1) is 70% by mass or less, a sufficient amount of positive electrode active material can be ensured.

[0039] As the positive electrode active material, any positive electrode active material capable of intercalating and releasing lithium ions is acceptable. For example, known positive electrode active materials used in lithium-ion secondary batteries can be used. For example, a composite metal oxide can be used as the positive electrode active material. Examples of composite metal oxides include lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), lithium manganese oxide (LiMnO2), lithium manganese spinel (LiMn2O4), and LiNix Co y Mn z M a Compound of O2 (in the general formula, x + y + z + a = 1, 0 ≤ x < 1, 0 ≤ y < 1, 0 ≤ z < 1, 0 ≤ a < 1, M is one or more elements selected from Al, Mg, Nb, Ti, Cu, Zn, Cr), lithium vanadium compound (LiV2O5), olivine-type LiMPO4 (where M represents one or more elements selected from Co, Ni, Mn, Fe, Mg, Nb, Ti, Al, Zr or VO), lithium titanate (Li4Ti5O 12 )、LiNi x Co y Al z O2 (0.9 < x + y + z < 1.1), etc. are mentioned. The positive electrode active material may be an organic substance. Examples of the organic substance include polyacetylene, polyaniline, polypyrrole, polythiophene, polyacene, etc.

[0040] The positive electrode active material may be a cation-free material. Examples of the cation-free material include FeF3, a conjugated polymer containing an organic conductive substance, Chevrel phase compound, transition metal chalcogenide, vanadium oxide, niobium oxide, etc. The cation-free material may use only one of the materials or may be used in combination of plural materials. When the positive electrode active material is a cation-free material, for example, discharge is first performed. By discharge, cations are inserted into the positive electrode active material. In addition, the cation-free material may be pre-doped with cations chemically or electrochemically.

[0041] The positive electrode 10 may contain a conductive assistant and / or a binder in addition to the positive electrode active material and the halide-based solid electrolyte represented by the formula (1). Conductive additives enhance the electronic conductivity between positive electrode active materials. Examples of conductive additives include carbon powder, carbon nanotubes, carbon materials, metal powders, mixtures of carbon materials and metal powders, and conductive oxides. Examples of carbon powders include carbon black, acetylene black, and Ketjen black. Examples of metal powders include fine powders made of copper, nickel, stainless steel, and iron.

[0042] The binder binds the positive electrode active materials together. Known binders can be used. Binders that are oxidation-resistant and adhesive are preferred. Examples of binders that can be used include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyamide (PA), polyimide (PI), polyamideimide (PAI), polybenzimidazole (PBI), polyethersulfone (PES), polyacrylic acid and its copolymers, metal ion crosslinked polyacrylic acid and its copolymers, polypropylene (PP) or polyethylene (PE) grafted with maleic anhydride, and mixtures thereof. Polyvinylidene fluoride (PVDF) is particularly preferred as the binder contained in the positive electrode 10.

[0043] "Negative electrode" The negative electrode 20 comprises a negative electrode active material and a halide-based solid electrolyte represented by formula (1). The negative electrode 20 may contain, as the solid electrolyte, not only the halide-based solid electrolyte represented by formula (1), but also a solid electrolyte other than the halide-based solid electrolyte represented by formula (1). Examples of other solid electrolytes include known solid electrolytes such as oxide-based solid electrolytes, sulfide-based solid electrolytes, and hydride-based solid electrolytes.

[0044] The content of the halide-based solid electrolyte represented by formula (1) in the negative electrode 20 can be, for example, 10% to 70% by mass, and preferably 10% to 30% by mass. When the content of the halide-based solid electrolyte represented by formula (1) is 10% by mass or more, the effect of improving the ionic conductivity within the negative electrode 20 due to the inclusion of the halide-based solid electrolyte represented by formula (1) becomes significant. When the content of the halide-based solid electrolyte represented by formula (1) is 70% by mass or less, a sufficient amount of negative electrode active material can be ensured.

[0045] As the negative electrode active material, any negative electrode active material capable of intercalating and releasing lithium ions is acceptable. For example, known negative electrode active materials used in lithium-ion secondary batteries can be used. Examples of negative electrode active materials include lithium titanate (LTO:Li 4-7 Ti5O 12 For example, Li4Ti5O 12 ), titanium dioxide (TiO2), Ni-TiO2, titanium niobium oxide (TNO:TiNb2O7), lithium oxide (LiO2), HTO (e.g., H2Ti 12 O 25 ), sulfur-modified polyacrylonitrile (SPAN), etc. can be used. The negative electrode active material is preferably a titanium oxide (a compound containing titanium and oxygen) because it is a stable negative electrode 20 with low reactivity with the solid electrolyte, and specifically lithium titanate (LTO: for example Li4Ti5O 12 Preferably, the material is titanium dioxide (TiO2), Ni-TiO2, or titanium niobium oxide (TNO:TiNb2O7), and lithium titanate (LTO:e.g., Li4Ti5O) 12 ) is the most preferable.

[0046] The negative electrode active material may be, for example, metallic lithium, metallic magnesium, lithium alloys, magnesium alloys, carbon materials, or materials that can alloy with cations. Examples of carbon materials include graphite (natural graphite, artificial graphite) capable of intercalating and releasing ions, carbon nanotubes, non-graphitizable carbon, easily graphitizable carbon, and low-temperature calcined carbon. Examples of materials that can alloy with cations include silicon, tin, zinc, lead, and antimony. The materials that can alloy with cations may be these elemental metals, or alloys or oxides containing these elements.

[0047] The negative electrode active material is, for example, Li + It is preferable that the electrode potential is in the range of 0.5V or higher relative to the Li equilibrium potential. + If the lithium ion potential is 1.0V(vs Li), even if the negative electrode 20 is positioned in contact with the inner surface of the second container 42, the reaction between the negative electrode active material and lithium ions is more likely to occur than the reaction between the coating layer 50 and lithium ions. Therefore, the reaction between the coating layer 50 and lithium ions can be suppressed, and good battery characteristics can be obtained. The electrode potential of the negative electrode active material is 1.0V(vs Li). + It is preferable that the value is 1 / Li or higher.

[0048] Of the negative electrode active materials mentioned above, Li + As a negative electrode active material having an electrode potential in the range of 0.5V or higher relative to the Li equilibrium potential, lithium titanate (LTO:Li4Ti5O) is a titanium oxide. 12 (1.55V(vs Li + / Li)),TiNb2O7(1.6V(vs Li + / Li)), sulfur-modified polyacrylonitrile (SPAN) (2.0V (vs Li) + Examples include / Li)).

[0049] The negative electrode 20 may contain a conductive additive and / or a binder in addition to the negative electrode active material and the halide-based solid electrolyte represented by formula (1). The conductive additive included in the negative electrode 20 can be the same as the conductive additive that may be included in the positive electrode 10. In addition to the binders that may be included in the positive electrode 10, the binder included in the negative electrode 20 can be, for example, cellulose, styrene-butadiene rubber, ethylene-propylene rubber, polyimide resin, polyamide-imide resin, acrylic resin, etc. As an example of cellulose, carboxymethylcellulose (CMC) can be used.

[0050] "Solid electrolyte layer" The solid electrolyte layer 30 consists of a halide-based solid electrolyte represented by formula (1). The solid electrolyte layer 30 may contain materials other than the halide-based solid electrolyte represented by formula (1), such as a solid electrolyte other than the halide-based solid electrolyte represented by formula (1). Examples of other solid electrolytes include known solid electrolytes such as oxide-based solid electrolytes, sulfide-based solid electrolytes, and hydride-based solid electrolytes.

[0051] If the solid electrolyte layer 30 contains a material other than the halide-based solid electrolyte represented by formula (1), the content of the halide-based solid electrolyte represented by formula (1) in the solid electrolyte layer 30 can be, for example, 50% to 100% by mass, and preferably 90% to 100% by mass. When the content of the halide-based solid electrolyte represented by formula (1) is 50% by mass or more, the effect of including the halide-based solid electrolyte represented by formula (1) becomes significant.

[0052] [Manufacturing method for all-solid-state batteries] The all-solid-state battery 100 of this embodiment can be manufactured, for example, by the method shown below. First, the power generation element 70 is manufactured, for example, by the method shown below. A solid electrolyte layer 30 is formed by placing a halide-based solid electrolyte powder represented by formula (1) into a cylindrical mold having a predetermined planar shape and height, and then press-molding it.

[0053] Next, the negative electrode active material, the halide-based solid electrolyte represented by formula (1), and the conductive additive are kneaded together to form a negative electrode mixture. Then, the negative electrode mixture is placed on the solid electrolyte layer 30 formed inside the cylindrical mold and pressure-molded. This forms a negative electrode 20 that is integrated with the solid electrolyte layer 30. Next, the positive electrode active material, the halide-based solid electrolyte represented by formula (1), and the conductive additive are kneaded together to form a positive electrode mixture. Then, the positive electrode mixture is placed on the solid electrolyte layer 30 opposite to the negative electrode 20 formed inside the cylindrical mold and pressure-molded. This forms a positive electrode 10 that is integrated with the solid electrolyte layer 30 and the negative electrode 20.

[0054] Subsequently, a pellet-shaped power generation element 70, in which the positive electrode 10, solid electrolyte layer 30, and negative electrode 20 are stacked in that order and integrated, is removed from the cylindrical shape. In this embodiment, the case in which the positive electrode 10 is formed after the negative electrode 20 has been formed has been described as an example, but the negative electrode 20 may be formed after the positive electrode 10 has been formed.

[0055] Next, the power generation element 70 is housed in the metal container 40. Specifically, a first container 41 and a second container 42 are prepared, both being metal containers 40 whose entire inner surface is covered with a coating layer 50. Next, a power generation element 70 is placed inside the first container 41 so that the positive electrode 10 is positioned in contact with the inner surface of the first container 41. Then, the second container 42 is placed on top of the first container 41, and a gasket 60 is placed between the edge of the first container 41 and the edge of the second container 42 and fitted together. This electrically connects the first container 41 and the positive electrode 10, and also electrically connects the second container 42 and the negative electrode 20. After that, the sides of the second container 42 are tightened, and the first container 41 and the second container 42 are sealed with the gasket 60. By following the above steps, the all-solid-state battery 100 of this embodiment can be obtained.

[0056] In this embodiment, the all-solid-state battery 100 contains a positive electrode 10, a negative electrode 20, and a solid electrolyte layer 30 that contain a halide-based solid electrolyte represented by formula (1), and at least a portion of the inner surface of the metal container 40 (first container 41 and second container 42) is covered with a coating layer 50. The coating layer 50 contains at least one metal selected from aluminum, nickel, titanium, and zirconium, an alloy containing the said metal, and an oxide containing the said metal. Therefore, in this embodiment, the all-solid-state battery 100 can suppress the reaction in which the inner surface of the metal container 40 is reduced by the halide-based solid electrolyte, and can prevent a decrease in capacity retention rate due to deterioration of the inner surface of the metal container 40.

[0057] <Second Embodiment> Figure 2 is a schematic cross-sectional view showing a solid-state battery of the second embodiment. The solid-state battery 200 shown in Figure 2 has a power generation element 71 and a metal container 40 that houses the power generation element 71. The only difference between the solid-state battery 200 shown in Figure 2 and the solid-state battery 100 shown in Figure 1 is that the power generation element 71 has a current collector layer 21 on the side of the negative electrode 20 facing the second container 42. Therefore, in the solid-state battery 200 shown in Figure 2, the same reference numerals are used for the same components as in the solid-state battery 100 shown in Figure 1, and their descriptions are omitted.

[0058] As shown in Figure 2, a current collector layer 21 is placed between the inner surface of the second container 42 of the metal container 40 and the negative electrode 20. The current collector layer 21 is made of a material with high conductivity. Preferably, the current collector layer 21 is made of a metal or alloy thereof such as silver, palladium, gold, platinum, aluminum, copper, nickel, stainless steel, or iron, or a conductive resin. The current collector layer 21 may also be in the form of powder, foil, punched, or expanded material.

[0059] The all-solid-state battery 200 of this embodiment can be manufactured, for example, by the method shown below. A pellet-shaped power generation element 70 is manufactured in the same manner as when manufacturing the all-solid-state battery 100 of the first embodiment. The power generation element 70 is then placed in the first container 41 such that the positive electrode 10 is in contact with the inner surface of the first container 41. Next, a current collector layer 21 is placed on the negative electrode 20 of the power generation element 70. After that, the second container 42 is placed on the first container 41, and a gasket 60 is placed between the edge of the first container 41 and the edge of the second container 42 and fitted together. This electrically connects the first container 41 and the positive electrode 10, and electrically connects the second container 42 and the negative electrode 20 via the current collector layer 21. After that, the sides of the second container 42 are tightened, and the first container 41 and the second container 42 are sealed with the gasket 60. By following the above steps, the all-solid-state battery 200 of this embodiment can be obtained.

[0060] In the all-solid-state battery 200 of this embodiment, similar to the all-solid-state battery 100 of the first embodiment, the positive electrode 10, the negative electrode 20, and the solid electrolyte layer 30 contain a halide-based solid electrolyte represented by formula (1), and at least a portion of the inner surface of the metal container 40 (first container 41 and second container 42) is covered with a coating layer 50. Therefore, the all-solid-state battery 200 of this embodiment, similar to the all-solid-state battery 100 of the first embodiment, can suppress the reaction in which the inner surface of the metal container 40 is reduced by the halide-based solid electrolyte, and can prevent a decrease in capacity retention rate due to deterioration of the inner surface of the metal container 40.

[0061] Furthermore, in the all-solid-state battery 200 of this embodiment, a current collector layer 21 is arranged between the inner surface of the second container 42 of the metal container 40 and the negative electrode 20. Therefore, the coating layer 50 covering the inner surface of the second container 42 and the negative electrode active material contained in the negative electrode 20 are less likely to come into contact. Consequently, even if the reaction between the coating layer 50 and lithium ions is more likely to occur than the reaction between the negative electrode active material and lithium ions, the reaction between the coating layer 50 and lithium ions is suppressed, and good battery characteristics can be obtained.

[0062] Although embodiments of the present invention have been described in detail above with reference to the drawings, the configurations and combinations thereof in each embodiment are merely examples, and additions, omissions, substitutions, and other modifications to the configurations are possible without departing from the spirit of the present invention.

[0063] For example, in the embodiments described above, the case in which the positive electrode 10, the negative electrode 20, and the solid electrolyte layer 30 all contain a halide-based solid electrolyte represented by formula (1) was used as an example. However, in the all-solid-state battery of the present invention, the power generation element only needs to have at least one of the positive electrode 10, the negative electrode 20, and the solid electrolyte layer 30 contain a halide-based solid electrolyte represented by formula (1). For example, only the solid electrolyte layer 30 may contain a halide-based solid electrolyte represented by formula (1), or only the solid electrolyte layer 30 and the negative electrode 20 may contain a halide-based solid electrolyte represented by formula (1).

[0064] Furthermore, the power generation element in the all-solid-state battery of the present invention may have a current collector layer on the side of the positive electrode 20 facing the first container 41. The current collector layer, which is disposed between the inner surface of the first container 41 of the metal container 40 and the positive electrode 10, is made of a material with high conductivity. As the material of the current collector layer, for example, metals such as silver, palladium, gold, platinum, aluminum, copper, nickel, titanium, stainless steel and their alloys, or conductive resins can be used. This current collector layer may be in the form of powder, foil, punched, or expanded.

[0065] Furthermore, although the above-described embodiment described an example in which the battery element has a stacked type in which only one layer each of the positive electrode 10, solid electrolyte layer 30, and negative electrode 20 are stacked, the power generation element in the all-solid-state battery of the present invention may be made up of multiple stacked structures in which the positive electrode 10, solid electrolyte layer 30, and negative electrode 20 are stacked. In this case, one end of each positive electrode 10 is electrically connected to the first container 41 via a known terminal. Also, one end of each negative electrode 20 is electrically connected to the second container 42 via a known terminal. Moreover, the power generation element in the all-solid-state battery of the present invention may be a wound type in which a sheet-like stack consisting of the positive electrode 10, solid electrolyte layer 30, and negative electrode 20 is wound. [Examples]

[0066] [ Reference example 1] The method shown below is used to obtain the result shown in Figure 1. Reference example We manufactured 100 all-solid-state batteries. First, the power generation element 70 was manufactured by the method shown below. A solid electrolyte layer 30 with a thickness of 600 μm was formed by placing 100 mg of solid electrolyte powder consisting of Li2ZrCl6 (LZC) into a cylindrical mold with a diameter of 10 mm and press-molding it with a force of 6 kN using a punch with a diameter of 10 mm.

[0067] Next, lithium titanate (Li4Ti5O 12 A negative electrode active material consisting of ), a solid electrolyte consisting of Li2ZrCl6 (LZC), and a conductive additive consisting of carbon (SuperP, trade name; manufactured by Imerys) were weighed and mixed in a mass ratio of 65:30:5. The mixture was kneaded in a mortar for 15 minutes to obtain a negative electrode mixture. Then, 10 mg of the negative electrode mixture was placed on the solid electrolyte layer 30 formed in a cylindrical mold and pressed and molded at 6 kN using a 10 mm diameter punch. This formed a negative electrode 20 with a thickness of 60 μm that was integrated with the solid electrolyte layer 30.

[0068] Next, a positive electrode active material consisting of lithium cobalt oxide (LiCoO2), a solid electrolyte consisting of Li2ZrCl6 (LZC), and a conductive additive consisting of carbon (SuperP, trade name; manufactured by Imerys) were weighed and mixed in a mass ratio of 65:32.5:2.5. The mixture was kneaded in a mortar for 15 minutes to obtain a positive electrode mixture. Then, 11 mg of the positive electrode mixture was placed on the solid electrolyte layer 30 opposite to the negative electrode 20 formed in the cylindrical mold, and it was pressure molded at 20 kN using a 10 mm diameter punch. This formed a positive electrode 10 with a thickness of 60 μm, which was integrated with the solid electrolyte layer 30 and the negative electrode 20. Subsequently, the cylindrical shape is transformed into a pellet-shaped structure in which the positive electrode 10, solid electrolyte layer 30, and negative electrode 20 are stacked in that order and integrated. Reference example The power generation element 70 was removed from unit 1.

[0069] Next, a first container 41 and a second container 42, both 20 mm in diameter, were prepared, made of stainless steel and coated with a coating layer 50 made of aluminum on their entire inner and outer surfaces. The coating layer 50 of the first container 41 was formed using an electroplating method. The plating was performed for 180 seconds using a toluene solution containing NaF-Al(C2H5)3 as the plating bath, with the current value fixed at 1 mA. The coating layer 50 of the second container 42 was formed separately from the coating layer 50 of the first container 41, using the same electroplating method under the same conditions as the coating layer 50 of the first container 41.

[0070] The thickness of the formed coating layer 50 was measured using a fluorescence X-ray analyzer (product name: Primus IV, manufactured by Rigaku Corporation) by the method described below. Specifically, the thickness was measured at five locations: the center of the inner surface of the first container 41 and the second container 42 covered with the coating layer 50, and four points on a line perpendicular to the center and 5 mm away from the center. The average value of these measurements was taken as the thickness of the coating layer 50. The results are shown in Table 1.

[0071] Next, in the first container 41, Reference exampleThe power generation element 70 was installed so that the positive electrode 10 was positioned in contact with the inner surface of the first container 41. Then, the second container 42 was placed on top of the first container 41, and a gasket 60 (product name: polypropylene gasket, manufactured by Hosen Co., Ltd.) was placed between the edge of the first container 41 and the edge of the second container 42 and fitted together. This electrically connected the first container 41 and the positive electrode 10, and also electrically connected the second container 42 and the negative electrode 20. After that, the sides of the second container 42 were tightened, and the first container 41 and the second container 42 were sealed with the gasket 60. Through the above process, a diameter of 20 mm and a height of 1.2 mm is produced. Reference example A solid-state battery 100 was obtained.

[0072] [ Reference example 2 Example 3 ~Example 5] Aside from changing the time for which the electric current was applied when forming the coating layer 50 on the first container 41 and the second container 42 using the electroplating method, Reference example In the same manner as in 1, Reference example 2 Example 3 ~An all-solid-state battery 100 was obtained in Example 5. Reference example 2 Example 3 ~The time for applying current in Example 5 is, Reference example 2 Example 3 ~The thickness of the coating layer 50 in Example 5 shall be as shown in Table 1. Reference example The thickness of the coating layer 50 was calculated in proportion to the relationship between the thickness of the coating layer 50 and the time the current was passed. The thickness of the coating layer 50 formed on the first container 41 and the second container 42 was calculated as follows: Reference example The measurements were taken in the same manner as in step 1. The results are shown in Table 1.

[0073] [ Reference example 6] Aside from the fact that when forming the coating layer 50 in the first container 41 and the second container 42 using an electroplating method, a mixed solution containing nickel sulfate, nickel chloride, and boric acid was used as the plating bath, Reference example In the same manner as in 1, Reference example A solid-state battery 100 was obtained. The thickness of the coating layer 50 formed on the first container 41 and the second container 42 was Reference example The measurements were taken in the same manner as in step 1. The results are shown in Table 1.

[0074] [ Reference example 7 Example 8 ~Example 10] Aside from changing the time for which the electric current was applied when forming the coating layer 50 on the first container 41 and the second container 42 using the electroplating method, Reference example In the same manner as in 6, Reference example 7 Example 8 ~An all-solid-state battery 100 was obtained in Example 10. Reference example 7 Example 8 ~The time for applying current in Example 10 is, Reference example 7 Example 8 ~The thickness of the coating layer 50 in Example 10 should be as shown in Table 1. Reference example The thickness of the coating layer 50 of container 6 was calculated in proportion to the relationship between the thickness of the coating layer 50 and the time the current was passed. The thickness of the coating layer 50 formed on the first container 41 and the second container 42 was calculated as follows: Reference example The measurements were taken in the same manner as in step 1. The results are shown in Table 1.

[0075] [ Reference example 11] Aside from using an electroplating method to form a coating layer 50 in the first container 41 and the second container 42, a titanium hydroxide-sodium hydroxide solution was used as the plating bath and the current was applied for 120 seconds, Reference example In the same manner as in 1, Reference example Eleven all-solid-state batteries 100 were obtained. The thickness of the coating layer 50 formed on the first container 41 and the second container 42 was Reference example The measurements were taken in the same manner as in step 1. The results are shown in Table 1.

[0076] [ Reference example 12 Example 13 ~Example 15] Aside from changing the time for which the electric current was applied when forming the coating layer 50 on the first container 41 and the second container 42 using the electroplating method, Reference example In the same manner as in 11, Reference example 12 Example 13 ~An all-solid-state battery 100 was obtained in Example 15. Reference example 12 Example 13 ~The time for applying current in Example 15 is, Reference example 12 Example 13~The thickness of the coating layer 50 in Example 15 should be as shown in Table 1. Reference example The thickness of the coating layer 50 was calculated in proportion to the relationship between the thickness of the 11 coating layer 50 and the time the current was passed. The thickness of the coating layer 50 formed on the first container 41 and the second container 42 was calculated as follows: Reference example The measurements were taken in the same manner as in step 1. The results are shown in Table 1.

[0077] [ Reference example 16] Aside from using an electroplating method to form a coating layer 50 in the first container 41 and the second container 42, an ammonium zirconate fluoride solution was used as the plating bath and the current was applied for 180 seconds, Reference example In the same manner as in 1, Reference example Sixteen all-solid-state batteries 100 were obtained. The thickness of the coating layer 50 formed on the first container 41 and the second container 42 was Reference example The measurements were taken in the same manner as in step 1. The results are shown in Table 1.

[0078] [ Reference example 17 Example 18 ~Example 20] Aside from changing the time for which the electric current was applied when forming the coating layer 50 on the first container 41 and the second container 42 using the electroplating method, Reference example In the same manner as in 16, Reference example 17 Example 18 ~An all-solid-state battery 100 was obtained in Example 20. Reference example 17 Example 18 ~The time for applying current in Example 20 is, Reference example 17 Example 18 ~The thickness of the coating layer 50 in Example 20 shall be as shown in Table 1. Reference example The thickness of the 16 coating layers 50 was calculated in proportion to the relationship between the thickness of the coating layer 50 and the time the current was applied. The thickness of the coating layer 50 formed on the first container 41 and the second container 42 was calculated as follows: Reference example The measurements were taken in the same manner as in step 1. The results are shown in Table 1.

[0079] [Example 21] Aside from the fact that, before forming the coating layer 50 on the first container 41 and the second container 42 using an electroplating method, a mask made of masking tape was applied to the areas on the inner surface of the first container 41 and the second container 42 where the coating layer 50 was not to be formed, and then the coating layer 50 was formed, and the mask was removed after the coating layer 50 was formed, Reference example In the same manner as in 1, Example 21 We obtained a total solid-state battery 100.

[0080] The mask was formed by applying masking tape to the inner surfaces of the first container 41 and the second container 42 in a shape that covered 50% of the inner surface area. The area where the mask was applied was limited to a circular area concentric with the first container 41 and the second container 42 in a plan view. The mask was removed by peeling off the masking tape. The thickness of the coating layer 50 formed on the first container 41 and the second container 42 was... Reference example The measurements were taken in the same manner as in step 1. The results are shown in Table 2.

[0081] [Examples 22-25] All-solid-state batteries 100 in Examples 22 to 25 were obtained in the same manner as in Example 21, except that the area of ​​the region where the mask was provided on the inner surfaces of the first container 41 and the second container 42 was changed. In Examples 22 to 25, the region where the mask was provided was limited to a circular area concentric with the first container 41 and the second container 42 in a plan view. The thickness of the coating layer 50 formed on the first container 41 and the second container 42 was changed. Reference example The measurements were taken in the same manner as in step 1. The results are shown in Table 2.

[0082] [ Reference example 26 Reference Example 27, Example 28 ~Example 30] Aside from the fact that Li2ZrSO4Cl4 (LZSOC) was used as the solid electrolyte when forming the positive electrode 10, the negative electrode 20, and the solid electrolyte layer 30, Reference example 1 , reference example 2 Example 3 ~In the same manner as in Example 5, Reference example 26 Reference Example 27, Example 28 ~An all-solid-state battery 100 was obtained in Example 30. Reference example 26 Reference Example 27, Example 28In the all-solid-state battery 100 of Example 30, the first container 41 and the second container 42 are, Reference example 1 , reference example 2 Example 3 The same materials used in Example 5 were employed.

[0083] [Example 31] Aside from installing a 10 μm thick copper current collector layer 21 on the negative electrode 20 of the power generation element 70, then installing the second container 42 on the first container 41, and installing a gasket 60 between the edge of the first container 41 and the edge of the second container 42 to fit them together, Reference example In the same manner as in 1, an all-solid-state battery 200 of Example 31 shown in Figure 2 was obtained. In the all-solid-state battery 200 of Example 31, the first container 41 and the second container 42 were: Reference example The same thing as in 1 was used.

[0084] [Example 32] Except for installing a 10 μm thick copper current collector layer 21 on the negative electrode 20 of the power generation element 70, then installing the second container 42 on the first container 41, and installing a gasket 60 between the edge of the first container 41 and the edge of the second container 42 to fit them together, the all-solid-state battery 200 of Example 32 shown in Figure 2 was obtained in the same manner as in Example 21. In the all-solid-state battery 200 of Example 32, the same first container 41 and second container 42 as in Example 21 were used.

[0085] [Example 33] Except for using Li2ZrSO4Cl4(LZSOC) as the solid electrolyte when forming the positive electrode 10, the negative electrode 20, and the solid electrolyte layer 30, an all-solid-state battery 200 of Example 33, shown in Figure 2, was obtained in the same manner as in Example 32. In the all-solid-state battery 200 of Example 33, the same first container 41 and second container 42 as in Example 21 were used.

[0086] [Comparative Example 1] Aside from not forming a coating layer 50 on the first container 41 and the second container 42, Reference example A solid-state battery for Comparative Example 1 was obtained in the same manner as in 1.

[0087] (Measurement of capacity retention rate after 100 cycles) Using an electrochemical testing apparatus (manufactured by Hokuto Denko Co., Ltd.), the following method is used: Reference Example 1, Reference Example 2, Examples 3-5, Reference Example 6, Reference Example 7, Examples 8-10, Reference Example 11, Reference Example 12, Examples 13-15, Reference Example 16, Reference Example 17, Examples 18-25, Reference Example 26, Reference Example 27, Example 28 Constant current charge-discharge (CC-CC) tests were performed on the all-solid-state batteries of Example 33 and Comparative Example 1. The battery was charged using a constant current charge rate of 0.1C (the current value at which charging is completed in 10 hours when charging at 1mA at 25℃) until the battery voltage reached 2.75V (CC charging), and then discharged using a constant current discharge rate of 0.1C until the battery voltage reached 1.3V (CC discharge). The discharge capacity (μAh) after the completion of charging and discharging was detected, and the discharge capacity Q1 of the first cycle was determined.

[0088] The solid-state battery whose battery capacity Q1 was determined was then charged again using a constant current charge rate of 0.1C until the battery voltage reached 2.75V (CC charging), and then discharged using a constant current discharge rate of 0.1C until the battery voltage reached 1.3V (CC discharge). Each of these charge and discharge cycles was counted as one cycle, and 100 charge and discharge cycles were performed. After that, the discharge capacity Q2 was determined after 100 charge and discharge cycles.

[0089] From the discharge capacities Q1 and Q2 obtained in this manner, the capacity retention rate E after 100 cycles was calculated using the following formula. The results are shown in Table 1 or Table 2. E(%) = (Q2 / Q1) × 100

[0090] [Table 1]

[0091] [Table 2]

[0092] As shown in Table 1 and Table 2, Reference Example 1, Reference Example 2, Examples 3-5, Reference Example 6, Reference Example 7, Examples 8-10, Reference Example 11, Reference Example 12, Examples 13-15, Reference Example 16, Reference Example 17, Examples 18-25, Reference Example 26, Reference Example 27, Example 28 The all-solid-state battery in Example 33 had a higher capacity retention rate compared to the all-solid-state battery in Comparative Example 1. This is because, Reference Example 1, Reference Example 2, Examples 3-5, Reference Example 6, Reference Example 7, Examples 8-10, Reference Example 11, Reference Example 12, Examples 13-15, Reference Example 16, Reference Example 17, Examples 18-25, Reference Example 26, Reference Example 27, Example 28In the all-solid-state battery of Example 33, a coating layer 50 is formed on at least a portion of the inner surfaces of the first container 41 and the second container 42, which is presumed to be due to the suppression of the reaction in which the inner surface of the metal container 40 is reduced by the halide-based solid electrolyte.

[0093] Furthermore, from the capacity retention rate results of the all-solid-state batteries in Examples 3 and 21 to 25 shown in Tables 1 and 2, it was confirmed that all-solid-state batteries in which 90% or more of the surface area of ​​the inner surfaces of the first container 41 and the second container 42 are covered with the coating layer 50 have particularly high capacity retention rates. Also, as shown in Tables 1 and 2 Reference Example 1, Reference Example 2, Examples 3-5, Reference Example 6, Reference Example 7, Examples 8-10, Reference Example 11, Reference Example 12, Examples 13-15, Reference Example 16, Reference Example 17, Example 18 ~Example 20, Reference Example 26, Reference Example 27, Example 28 From the capacity retention rate results of the all-solid-state battery in Example 30, it was confirmed that the capacity retention rate was particularly high in all-solid-state batteries with a coating layer thickness of 0.05 μm or more.

[0094] Furthermore, from the capacity retention rate results of the all-solid-state batteries in Examples 21 and 32 shown in Table 2, it was confirmed that when the area covered by the coating layer 50 was 50%, the all-solid-state battery in which the current collector layer 21 was installed on the negative electrode 20 had a high capacity retention rate. This is presumed to be because the installation of the current collector layer 21 suppressed the reaction between the portion of the inner surface of the metal container 40 that was not covered by the coating layer 50 and the gas generated from the halide-based solid electrolyte. [Explanation of Symbols]

[0095] 10...Positive electrode, 20...Negative electrode, 21...Current collector layer, 30...Solid electrolyte layer, 40...Metal container, 41...First container, 42...Second container, 50...Coating layer, 60...Gasket, 70, 71...Power generation element, 100, 200...All-solid-state battery.

Claims

1. A power generation element comprising a positive electrode, a negative electrode, and a solid electrolyte layer interposed between the positive electrode and the negative electrode, It has a metal container that houses the power generation element, At least one of the positive electrode, the negative electrode, and the solid electrolyte layer contains a halide-based solid electrolyte represented by the following formula (1): The metal container is made of a metal selected from stainless steel, copper, nickel, and aluminum, and at least a portion of the inner surface of the metal container is covered with a coating layer. The coating layer comprises at least one metal selected from aluminum, nickel, titanium, and zirconium, an alloy containing the said metal, and an oxide containing the said metal. An all-solid-state battery characterized in that the thickness of the coating layer is 0.05 μm or more and 0.10 μm or less. LiaEbGcXd...(1) (In formula (1), E is at least one element selected from the group consisting of Al, Sc, Y, Zr, Hf, and lanthanoids. G is OH, BO ２ 、BO ３ 、BO ４ 、B ３ O ６ 、B ４ O ７ 、CO ３ 、NO ３ 、AlO ２ 、SiO ３ 、SiO ４ 、Si ２ O ７ 、Si ３ O ９ 、Si ４ O １１ 、Si ６ O １８ 、PO ３ 、PO ４ 、P ２ O ７ 、P ３ O １０ 、SO ３ 、SO ４ 、SO ５ 、S ２ O ３ 、S ２ O ４ 、S ２ O ５ 、S ２ O ６ 、S ２ O ７ 、S ２ O ８ 、BF ４ 、PF ６ 、BOB, (COO) ２ 、N, AlCl ４ 、CF ３ SO ３ 、CH ３ COO, CF ３ COO, O is at least one group selected from the group consisting of. X is at least one element selected from the group consisting of F, Cl, Br, and I. 0.5 ≦ a < 6, 0 < b < 2, 0 ≦ c ≦ 6, 0 < d ≦ 6.1.)

2. The all-solid-state battery according to claim 1, wherein 90% or more of the surface area of ​​the inner surface is covered with the coating layer.

3. The aforementioned negative electrode is Li ＋ An all-solid-state battery according to claim 1 or claim 2, comprising a negative electrode active material having an electrode potential in the range of 0.5 V or higher with respect to the Li equilibrium potential.

4. The all-solid-state battery according to claim 3, wherein the negative electrode active material comprises titanium oxide.

5. The all-solid-state battery according to claim 4, wherein the titanium oxide is lithium titanate.

6. The all-solid-state battery according to any one of claims 1 to 5, wherein a current collector layer is disposed between the inner surface of the metal container and the negative electrode.

Images