Solid electrolyte material and all-solid-state battery

Abstract

To provide a solid electrolyte material that has high ionic conductivity, and a rate characteristic-improved all-solid-state battery that includes the same.SOLUTION: The solid electrolyte material has a pair of surfaces facing each other and contains one or more of a predetermined halide-based solid electrolyte or sulfide-based solid electrolyte, and at least one of the pair of surfaces has a surface ten-point average roughness RzJIS in the range of 20 nm or more and 1500 nm or less.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a solid electrolyte material and an all-solid-state battery.

Background Art

[0002] In recent years, the development of electronics technology has been remarkable, and mobile electronic devices have been made smaller, lighter, thinner, and more multifunctional. Along with this, there is a strong demand for batteries, which are the power sources of electronic devices, to be made smaller, lighter, and more reliable. For this reason, all-solid-state batteries using solid electrolytes as electrolytes have attracted attention. Known solid electrolytes include oxide-based solid electrolytes, sulfide-based solid electrolytes, halide-based solid electrolytes, complex hydride-based solid electrolytes (such as LiBH4), and the like.

[0003] Examples of oxide-based solid electrolytes include NASICON-type solid electrolytes such as Li 1.3 Al 0.3 Ti 1.7 (PO4)3 (LATP), perovskite-type solid electrolytes such as La 0.51 Li 0.34 TiO 2.94 and garnet-type solid electrolytes such as Li7La3Zr2O 12 .

[0004] Patent Document 1 discloses a battery having a positive electrode including a positive electrode layer containing a positive electrode active material containing an Li element and a positive electrode current collector, a negative electrode including a negative electrode layer containing a negative electrode active material and a negative electrode current collector, and a solid electrolyte composed of a compound represented by the following general formula, which is sandwiched between the positive electrode layer and the negative electrode layer. Li 3-2X M X In 1-Y M´ Y L 6-Z L´ Z (In the formula, M and M´ are metal elements, and L and L´ are halogen elements. Also, X, Y, and Z independently satisfy 0 ≦ X < 1.5, 0 ≦ Y < 1, and 0 ≦ Z ≦ 6.)

[0005] Patent Document 2 discloses a halide-based solid electrolyte material represented by the following compositional formula. Li 6-3Z Y Z X6 Here, 0 < Z < 2 is satisfied, and X is Cl or Br. Patent Document 2 also describes a battery in which at least one of the negative electrode and the positive electrode contains the solid electrolyte material.

[0006] Patent Document 3 discloses an all-solid-state battery using a sulfide-based solid electrolyte, which includes an active material, a first solid electrolyte material that is in contact with the active material and has an anion component different from the anion component of the active material and is a single-phase electron-ion mixed conductor, and a second solid electrolyte material that is in contact with the first solid electrolyte material and has the same anion component as the first solid electrolyte material and is an ion conductor having no electron conductivity. A battery including an electrode active material layer having the above is disclosed. Patent Document 3 also discloses that the first solid electrolyte material is Li2ZrS3, the first solid electrolyte material has a peak of Li2ZrS3 at a position of 2θ = 34.2° ± 0.5° in X-ray diffraction measurement using CuKα rays, and the diffraction intensity of the peak of Li2ZrS3 at 2θ = 34.2° ± 0.5° is I A Let it be, and the diffraction intensity of the peak of ZrO2 at 2θ = 31.4° ± 0.5° is I B When it is the case, I B / I A The value of is disclosed to be 0.1 or less.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0008] However, in conventional all-solid-state batteries, the ionic conductivity of the solid electrolyte was insufficient. For this reason, all-solid-state batteries using conventional solid electrolytes had problems such as low discharge capacity at high current density, that is, poor rate characteristics.

[0009] The present invention has been made in view of the above problems, and an object thereof is to provide a solid electrolyte material having high ionic conductivity and an all-solid-state battery having improved rate characteristics including the same.

Means for Solving the Problems

[0010] In order to solve the above problems, the present inventors have conducted intensive studies. As a result, an all-solid-state battery using a solid electrolyte material containing one or more of a halide-based solid electrolyte or a sulfide-based solid electrolyte and having a surface roughened so that the surface ten-point average roughness Rz JIS is in the range of 20 nm or more and 1500 nm or less has been found to have improved rate characteristics, leading to the present invention. That is, the present invention provides the following means in order to solve the above problems.

[0011] [1] A solid electrolyte material having a pair of mutually facing surfaces and containing one or more of a halide-based solid electrolyte or a sulfide-based solid electrolyte represented by the following formula (1), wherein at least one of the pair of surfaces has a surface ten-point average roughness Rz JIS in the range of 20 nm or more and 1.5 μm or less. Li 2+a E 1-b G b D c X d ···(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 at least one element selected from the group consisting of Na, K, Rb, Cs, Mg, Ca, Sr, Ba, B, Si, Ti, Cu, Nb, Ag, In, Sn, Sb, Ta, W, Au, and Bi; D is at least one group selected from the group consisting of CO3, SO4, BO3, PO4, NO3, SiO3, OH, and O2; X is at least one selected from the group consisting of F, Cl, Br, and I; 0 ≦ a < 1.5, 0 ≦ b < 0.5, 0 ≦ c ≦ 5, and 0 < d ≦ 6.1.)

[0012] [2] The solid electrolyte material according to [1] above, wherein the average thickness is 2.0 μm or more.

[0013] [3] An all-solid-state battery comprising the solid electrolyte material according to [1] or [2] above, a positive electrode mixture layer in contact with one of the pair of surfaces of the solid electrolyte material, and a negative electrode mixture layer in contact with the other of the pair of surfaces of the solid electrolyte material.

Advantages of the Invention

[0014] According to the present invention, it is possible to provide a solid electrolyte material with high ionic conductivity and an all-solid-state battery having improved rate characteristics including the same.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0016] Hereinafter, the solid electrolyte material and the all-solid-state battery according to an embodiment of the present invention will be described in detail.

[0017] [Solid Electrolyte Material] The solid electrolyte material of this embodiment has a pair of surfaces facing each other. The solid electrolyte material is used as the solid electrolyte layer of an all-solid-state battery. When used as the solid electrolyte layer of an all-solid-state battery, one of the pair of surfaces of the solid electrolyte material contacts the positive electrode mixture layer, and the other contacts the negative electrode mixture.

[0018] The solid electrolyte material may have any shape with a pair of surfaces. For example, it may be in the form of a film (layer) or a pellet. At least one of the pair of surfaces of the solid electrolyte material has a surface ten-point average roughness Rz JIS in the range of 20 nm or more and 1500 nm or less and has fine irregularities. The surface with fine irregularities of the solid electrolyte material may be the side that contacts the positive electrode mixture layer or the side that contacts the negative electrode mixture layer. It is preferable that both of the pair of surfaces of the solid electrolyte material have fine irregularities.

[0019] The surface ten-point average roughness Rz JIS is obtained by extracting a reference length from the roughness curve in the direction of its mean line, measuring in the direction of the vertical magnification from the mean line of this extracted portion, and calculating the average value of the absolute values of the elevations of the fifth to the highest peaks and the average value of the absolute values of the elevations of the fifth to the lowest valleys, and expressing this value in nanometers.

[0020] The solid electrolyte material may have an average thickness of 2.0 μm or more. The thickness of the solid electrolyte material is the distance between the pair of surfaces. The thickness of the solid electrolyte material can be measured by observing the cross-section of a cross-section polished sample using an SEM (scanning electron microscope). The average thickness is the average of the thicknesses measured at 10 locations. It is preferable that the average thickness of the solid electrolyte material is 2.0 μm or more, and particularly preferably 10 μm or more. The average thickness of the solid electrolyte material may be 1000 μm or less.

[0021] The solid electrolyte material contains one or more of a halide-based solid electrolyte or a sulfide-based solid electrolyte. The solid electrolyte material may be a single halide-based solid electrolyte, a single sulfide-based solid electrolyte, or a mixture of a halide-based solid electrolyte and a sulfide-based solid electrolyte. The solid electrolyte material may contain a binder.

[0022] As the halide-based solid electrolyte, a compound represented by the following formula (1) is used. Li 2+a E 1-b G b D c X d ···(1)

[0023] In the compound represented by formula (1), E is an essential component and is one of the elements forming the skeleton of the compound represented by formula (1). E is at least one element selected from the group consisting of Al, Sc, Y, Zr, Hf, and lanthanoids (La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu). By including E, a solid electrolyte having a wide potential window and high ionic conductivity is obtained. As E, in order to obtain a solid electrolyte with higher ionic conductivity, it is preferably included Al, Sc, Y, Zr, Hf, La, and particularly preferably included Zr and Y.

[0024] In the compound represented by formula (1), G is a component contained as needed. G is at least one element selected from the group consisting of Na, K, Rb, Cs, Mg, Ca, Sr, Ba, B, Si, Ti, Cu, Nb, Ag, In, Sn, Sb, Ta, W, Au, and Bi. In the compound represented by formula (1), G may be a monovalent element selected from Na, K, Rb, Cs, Ag, and Au among the above. In the compound represented by formula (1), G may be a divalent element selected from Mg, Ca, Sr, Ba, Cu, and Sn among the above. In the compound represented by formula (1), G may be trivalent selected from B, Si, Ti, Nb, In, Sb, Ta, W, and Bi among the above.

[0025] In the compound represented by formula (1), D is an optionally contained component. D is at least one group selected from the group consisting of CO3, SO4, BO3, PO4, NO3, SiO3, OH, and O2. By including D, the potential window on the reduction side becomes wide. D is preferably at least one group selected from the group consisting of SO4 and CO3, and particularly preferably SO4.

[0026] In the compound represented by formula (1), it is an essential component and one of the elements forming the skeleton of the compound represented by formula (1). X is at least one halogen element selected from the group consisting of F, Cl, Br, and I. X has a large ionic radius per valence. Therefore, when the compound represented by formula (1) contains X, the lithium ions can move easily, and the effect of increasing the ionic conductivity can be obtained. As X, it is preferable to contain Cl in order to obtain a solid electrolyte with high ionic conductivity.

[0027] In the compound represented by formula (1), a, b, c, and d are numbers satisfying 0 ≦ a < 1.5, 0 ≦ b < 0.5, 0 ≦ c ≦ 5, and 0 < d ≦ 6.1, respectively. It is preferable that 0 ≦ a < 1.0, 0 ≦ b < 0.35, 0 ≦ c ≦ 3, and 1.5 < d ≦ 6.1.

[0028] Examples of the compound represented by formula (1) include Li2ZrCl6, Li2ZrSO4Cl4, Li2ZrCO3Cl4, Li3YSO4Cl4, and Li3YCO3Cl4.

[0029] The compound represented by formula (1) can be produced, for example, by a method of mixing and reacting raw material powders containing predetermined elements in a predetermined molar ratio. 2. The compound represented by formula (1) can be produced, for example, by a mechanochemical method. In order to cause a mechanochemical reaction, as a mixing device for raw material powders, for example, a planetary ball mill device can be used. A planetary ball mill device is a device that puts media (balls for promoting pulverization or mechanochemical reaction) and raw material powders into a sealed container, rotates and revolves, applies kinetic energy to the raw material powders, and causes pulverization or mechanochemical reaction. For the sealed container and balls of the planetary ball mill device, for example, those made of zirconia can be used.

[0030] As the sulfide-based solid electrolyte, a compound containing Li, S, and Si and / or P can be used. The sulfide-based solid electrolyte may further contain Ge, Cl, Br, or I. The sulfide-based solid electrolyte may be amorphous, crystalline, or argyrodite-type. Examples of the sulfide-based solid electrolyte include Li2S-P2S5-based solid electrolytes (Li7P3S 11 , Li3PS4, Li8P2S9, etc.), Li2S-SiS2, LiI-Li2S-SiS2, LiI-Li2S-P2S5, LiI-LiBr-Li2S-P2S5, Li2S-P2S5-GeS2-based solid electrolytes (Li 13 GeP3S 16 , Li 10 GeP2S 12 , etc.), LiI-Li2S-P2O5, LiI-Li3PO4-P2S5, Li7-xPS6-xCl x (x is 1.0 to 1.9).

[0031] The sulfide-based solid electrolyte may be a compound represented by the following formula (2). Li q M r P s O t X u S v ···(2) In formula (2), Li is lithium, M is a tetravalent metal, P is phosphorus, O is oxygen, S is sulfur, X is at least one selected from the group consisting of F, Cl, Br, and I, and q, r, s, t, u, and v are numbers that satisfy 1 ≦ q ≦ 20, 0 ≦ r ≦ 2, 1 ≦ s ≦ 5, 0 ≦ t ≦ 5, 0 ≦ u ≦ 5, and v = q / 2 + 2×r + 2.5×s - t - u / 2, respectively. M is preferably Si or Ge.

[0032] The solid electrolyte material can be manufactured, for example, by producing a flat solid electrolyte material having a surface ten-point average roughness Rz JIS of less than 20 nm on a pair of surfaces, and then roughening the surface of the solid electrolyte material to form fine irregularities. As a method for producing the solid electrolyte material, a pressing method, a rolling method, or a coating method can be used.

[0033] The pressing method is a method for producing a pellet-shaped solid electrolyte material by pressing a solid electrolyte using a pellet production jig having a cylindrical holder (die), an upper punch, and a lower punch that can be inserted into the cylindrical holder. Specifically, the lower punch is inserted into the cylindrical holder, the solid electrolyte is charged onto the lower punch, and then the upper punch is inserted onto the solid electrolyte. Then, the pellet production jig is placed on a press, and by pressing the lower punch and the upper punch, a pellet-shaped solid electrolyte material can be produced.

[0034] The rolling method is a method for producing a film-shaped solid electrolyte material by rolling a solid electrolyte composition containing a solid electrolyte and a binder using a pressing roller. Specifically, the powder of the solid electrolyte and the binder are mixed dry to obtain a solid electrolyte composition. Then, the solid electrolyte composition can be rolled using a pressing roller to produce a film-shaped solid electrolyte material. As the binder, for example, a fluororesin (PTFE) can be used.

[0035] The coating method is a method of producing a film-shaped solid electrolyte material by applying a solid electrolyte coating solution containing a solid electrolyte, a binder, and a solvent to a substrate and drying it. Specifically, a solid electrolyte, a binder, and a solvent are mixed to obtain a solid electrolyte coating solution. Then, the solid electrolyte coating solution is applied using a coating device such as a bar coater and then dried to produce a film-shaped solid electrolyte material. As the binder, for example, carboxymethyl cellulose (CMC) can be used.

[0036] As a method for roughening the surface of the solid electrolyte material, an electron beam irradiation method can be used. The electron beam irradiation method is a method of forming fine irregularities on the surface of the solid electrolyte material by irradiating the surface of the solid electrolyte material with an electron beam. By using this electron beam irradiation method, at least one of the pair of surfaces has a surface ten-point average roughness Rz JIS in the range of 20 nm or more and 1500 nm or less, a solid electrolyte material can be obtained.

[0037] The solid electrolyte material of the present embodiment configured as described above has a pair of surfaces facing each other, and at least one of the pair of surfaces has a surface ten-point average roughness Rz JIS of 20 nm or more. Therefore, by using this solid electrolyte material as the solid electrolyte layer of an all-solid-state battery, the contact area with the electrode mixture layer (positive electrode mixture layer, negative electrode mixture layer) adjacent to the solid electrolyte material can be increased. Thereby, the contact resistance between the solid electrolyte material and the electrode mixture layer can be reduced, and the ion conductivity between the solid electrolyte material and the electrode mixture layer is improved. Further, since the surface of the solid electrolyte material has a surface ten-point average roughness Rz JIS of 1500 nm or less, it is considered that the potential distribution is uniform and electrical degradation is less likely to occur locally. Therefore, an all-solid-state battery using the solid electrolyte material of the present embodiment as the solid electrolyte layer has improved rate characteristics.

[0038] In addition, in the solid electrolyte material of the present embodiment, when the average thickness is 2.0 μm or more, since the thickness of the solid electrolyte material is larger than the surface unevenness, it is considered that local strength reduction and breakage due to the surface unevenness are less likely to occur.

[0039] [All-solid-state battery] FIG. 1 is a schematic cross-sectional view of an all-solid-state battery according to an embodiment of the present invention. The all-solid-state battery 10 shown in FIG. 1 includes a positive electrode 1, a negative electrode 2, and a solid electrolyte layer 3. The solid electrolyte layer 3 is sandwiched between the positive electrode 1 and the negative electrode 2. The solid electrolyte layer 3 is made of the above-described solid electrolyte material. External terminals (not shown) are connected to the positive electrode 1 and the negative electrode 2, and they are electrically connected to the outside.

[0040] The all-solid-state battery 10 is charged or discharged by the transfer of ions through the solid electrolyte layer 3 between the positive electrode 1 and the negative electrode 2 and the transfer of electrons through the external circuit. The all-solid-state battery 10 may be a laminate in which the positive electrode 1, the negative electrode 2, and the solid electrolyte layer 3 are laminated, or may be a wound body in which the laminate is wound. The all-solid-state battery can be, for example, a laminated battery, a rectangular battery, a cylindrical battery, a coin-type battery, or a button-type battery.

[0041] (Positive electrode) As shown in FIG. 1, the positive electrode 1 is provided with a positive electrode mixture layer 1B on a plate-shaped (foil-shaped) positive electrode current collector 1A. The positive electrode 1 is arranged such that the positive electrode mixture layer 1B is adjacent to the solid electrolyte layer 3.

[0042] (Positive electrode current collector) The positive electrode current collector 1A may be an electron-conductive material that can withstand oxidation during charging and is resistant to corrosion. As the positive electrode current collector 1A, for example, metals such as aluminum, stainless steel, nickel, and titanium, or conductive resins can be used. The positive electrode current collector 1A may be in the form of powder, foil, punching, or expansion.

[0043] (Positive electrode mixture layer) The positive electrode active material layer 1B contains a positive electrode active material and, if necessary, a solid electrolyte, a binder, and a conductive assistant.

[0044] (Positive electrode active material) The positive electrode active material may be any material that can reversibly proceed with the insertion and extraction (intercalation and deintercalation) of lithium ions, and is not particularly limited. As the positive electrode active material, those used in known lithium ion secondary batteries can be used. Examples of the positive electrode active material include lithium-containing metal oxides, lithium-containing metal phosphates, and the like.

[0045] Examples of the lithium-containing metal oxide include lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), lithium manganese spinel (LiMn2O4), and the general formula: LiNi x Co y Mn z Composite metal oxides represented by O2 (x + y + z = 1), lithium vanadium compounds (LiVOPO4, Li3V2(PO4)3), olivine-type LiMPO4 (where M represents at least one selected from Co, Ni, Mn, and Fe), lithium titanate (Li4Ti5O 12 ) and the like.

[0046] In addition, positive electrode active materials that do not contain lithium can also be used. Examples of such positive electrode active materials include lithium-free metal oxides (MnO2, V2O5, etc.), lithium-free metal sulfides (MoS2, etc.), lithium-free fluorides (FeF3, VF3, etc.). When using these positive electrode active materials that do not contain lithium, the negative electrode may be doped with lithium ions in advance, or a negative electrode containing lithium ions may be used.

[0047] (Solid electrolyte) The solid electrolyte may be the same as or different from the solid electrolyte contained in the solid electrolyte layer 3. When the solid electrolyte in the positive electrode mixture layer 1B is the same as the solid electrolyte in the solid electrolyte layer 3, the ionic conductivity between the positive electrode mixture layer 1B and the solid electrolyte layer 3 is improved.

[0048] The content of the solid electrolyte in the positive electrode mixture layer 1B is not particularly limited, but is preferably 1 to 50% by volume, more preferably 5 to 50% by volume, based on the total volume of the positive electrode active material, solid electrolyte, conductive assistant, and binder.

[0049] (Binder) The binder binds the positive electrode active material, solid electrolyte, and conductive assistant that constitute the positive electrode mixture layer 1B to each other. Further, the binder adheres the positive electrode mixture layer 1B and the positive electrode current collector 1A. The required properties of the binder include oxidation resistance and good adhesiveness.

[0050] Examples of the binder used in the positive electrode mixture layer 1B include polyvinylidene fluoride (PVDF) or its copolymer, polytetrafluoroethylene (PTFE), polyamide (PA), polyimide (PI), polyamideimide (PAI), polybenzimidazole (PBI), polyethersulfone (PES), polyacrylic acid (PA) and its copolymer, a metal ion cross-linked product of polyacrylic acid (PA) and its copolymer, polypropylene (PP) grafted with maleic anhydride, polyethylene (PE) grafted with maleic anhydride, or a mixture thereof. Among these, it is particularly preferable to use PVDF as the binder.

[0051] The content rate of the binder in the positive electrode mixture layer 1B is not particularly limited, but is preferably 1 to 15% by volume, more preferably 3 to 5% by volume, based on the total volume of the positive electrode active material, the solid electrolyte, the conductive assistant, and the binder. If the content rate of the binder is too low, there is a tendency that the positive electrode 1 having sufficient adhesive strength cannot be formed. Also, general binders are electrochemically inert and do not contribute to the discharge capacity. For this reason, if the content rate of the binder is too high, it tends to be difficult to obtain a sufficient volume energy density or mass energy density.

[0052] (Conductive assistant) The conductive assistant is not particularly limited as long as it improves the electron conductivity of the positive electrode mixture layer 1B, and known conductive assistants can be used. For example, carbon materials such as carbon black, graphite (black lead), carbon nanotubes, and graphene, metals such as aluminum, copper, nickel, stainless steel, iron, and amorphous metal, conductive oxides such as ITO, or mixtures thereof can be mentioned. The conductive assistant may be in the form of powder or fiber.

[0053] The content rate of the conductive assistant in the positive electrode mixture layer 1B is not particularly limited. When the positive electrode mixture layer 1B contains a conductive assistant, it is preferably 0.5 to 20% by volume, more preferably 1 to 10% by volume, based on the total volume of the positive electrode active material, the solid electrolyte, the conductive assistant, and the binder.

[0054] (Negative electrode) As shown in FIG. 1, the negative electrode 2 is provided with a negative electrode mixture layer 2B on a negative electrode current collector 2A. The negative electrode 2 is arranged such that the negative electrode mixture layer 2B is adjacent to the solid electrolyte layer 3.

[0055] (Negative electrode current collector) The negative electrode current collector 2A only needs to have electron conductivity. As the negative electrode current collector 2A, for example, metals such as copper, aluminum, nickel, stainless steel, and iron, or conductive resins can be used. The negative electrode current collector 2A may be in the form of powder, foil, punching, or expansion.

[0056] (Negative electrode mixture layer) The negative electrode mixture layer 2B contains a negative electrode active material and, if necessary, a solid electrolyte, a binder, and a conductive assistant.

[0057] (Negative electrode active material) The negative electrode active material only needs to be able to reversibly proceed with the occlusion and release of lithium ions, and the insertion and desorption of lithium ions, and is not particularly limited. As the negative electrode active material, a negative electrode active material used in a known lithium ion secondary battery can be used. As the negative electrode active material, for example, carbon materials such as natural graphite, artificial graphite, mesocarbon microbeads, mesocarbon fibers (MCF), cokes, glassy carbon, and fired organic compounds, Si, SiO x , metals that can combine with lithium such as Sn, aluminum, alloys thereof, composite materials of these metals and carbon materials, lithium titanate (Li4Ti5O 12 ), oxides such as SnO2, and metallic lithium, etc. can be mentioned.

[0058] (Solid electrolyte) The solid electrolyte may be the same as or different from the solid electrolyte contained in the solid electrolyte layer 3. When the solid electrolyte in the negative electrode mixture layer 2B is the same as the solid electrolyte in the solid electrolyte layer 3, the ionic conductivity between the negative electrode mixture layer 2B and the solid electrolyte layer 3 is improved.

[0059] The content rate of the solid electrolyte in the negative electrode mixture layer 2B is not particularly limited, but based on the total volume of the negative electrode active material, the solid electrolyte, the conductive assistant, and the binder, it is preferably 1 to 50% by volume, and more preferably 5 to 50% by volume.

[0060] (Binder) The binder binds the negative electrode active material, the solid electrolyte, and the conductive assistant that constitute the negative electrode binder layer 2B to each other. Further, the binder adheres the negative electrode binder layer 2B and the negative electrode current collector 2A. The required properties of the binder include being reducible-resistant and having good adhesiveness.

[0061] Examples of the binder used in the negative electrode binder layer 2B include polyvinylidene fluoride (PVDF) or its copolymer, polytetrafluoroethylene (PTFE), polyamide (PA), polyimide (PI), polyamideimide (PAI), polybenzimidazole (PBI), styrene butadiene rubber (SBR), carboxymethyl cellulose (CMC), polyacrylic acid (PA) and its copolymer, a metal ion cross-linked product of polyacrylic acid (PA) and its copolymer, polypropylene (PP) grafted with maleic anhydride, polyethylene (PE) grafted with maleic anhydride, or a mixture thereof. Among these, as the binder, it is preferable to use one or more selected from SBR, CMC, and PVDF.

[0062] The content of the binder in the negative electrode binder layer 2B is not particularly limited, but based on the total volume of the negative electrode active material, the conductive assistant, and the binder, it is preferably 1% by volume to 15% by volume, and more preferably 1.5% by volume to 10% by volume. If the content of the binder is too small, there is a tendency that the negative electrode 2 having sufficient adhesive strength cannot be formed. Also, a general binder is electrochemically inert and does not contribute to the discharge capacity. For this reason, if the content of the binder is too large, it tends to be difficult to obtain a sufficient volume energy density or mass energy density.

[0063] (Conductive assistant) As the conductive assistant that may be included in the negative electrode binder layer 2B, a carbon material, a metal, a conductive oxide, or a mixture thereof can be used. Examples of the carbon material, the metal, and the conductive oxide are the same as those of the conductive assistant that may be included in the positive electrode binder layer 1B described above. The content rate of the conductive assistant in the negative electrode mixture layer 2B is not particularly limited. When the negative electrode mixture layer 2B contains a conductive assistant, it is preferably 0.5% by volume to 20% by volume, more preferably 1% by volume to 10% by volume, based on the total volume of the negative electrode active material, the solid electrolyte, the conductive assistant, and the binder.

[0064] (Outer package) In the all-solid-state battery of this embodiment, the battery element composed of the positive electrode 1, the solid electrolyte layer 3, and the negative electrode 2 is housed and sealed in an outer package. The outer package may be any one that can prevent the intrusion of moisture and the like from the outside to the inside, and is not particularly limited. For example, as the outer package, a metal laminate film formed by coating both sides of a metal foil with a polymer film and formed in a bag shape can be used. Such an outer package is sealed by heat-sealing the opening.

[0065] As the metal foil forming the metal laminate film, for example, aluminum foil, stainless steel foil, etc. can be used. As the polymer film disposed on the outside of the outer package, it is preferable to use a polymer with a high melting point, for example, polyethylene terephthalate (PET), polyamide, etc. As the polymer film disposed on the inside of the outer package, for example, polyethylene (PE), polypropylene (PP), etc. are preferably used.

[0066] (External terminal) A positive electrode terminal is electrically connected to the positive electrode 1 of the battery element. Also, a negative electrode terminal is electrically connected to the negative electrode 2. In this embodiment, the positive electrode terminal is electrically connected to the positive electrode current collector 1A. Also, the negative electrode terminal is electrically connected to the negative electrode current collector 2A. The connection portion between the positive electrode current collector 1A or the negative electrode current collector 2A and the external terminals (the positive electrode terminal and the negative electrode terminal) is disposed inside the outer package. As the external terminals, for example, those formed of a conductive material such as aluminum or nickel can be used.

[0067] Between the outer package and the external terminal, it is preferable that a film made of PE grafted with maleic anhydride (hereinafter sometimes referred to as "acid-modified PE") or PP grafted with maleic anhydride (hereinafter sometimes referred to as "acid-modified PP") is disposed. By heat-sealing the portion where the film made of acid-modified PE or acid-modified PP is disposed, an all-solid-state battery with good adhesion between the outer package and the external terminal is obtained.

[0068] Next, a method for manufacturing the all-solid-state battery 10 will be described. First, a solid electrolyte material that will become the solid electrolyte layer 3 of the all-solid-state battery 10 is prepared. Next, a positive electrode mixture layer 1B is formed on one surface of the solid electrolyte material, and a negative electrode mixture layer 2B is formed on the other surface. As a method for forming the positive electrode mixture layer 1B and the negative electrode mixture layer 2B, a pressing method, a coating method, or a pressure bonding method can be used.

[0069] The pressing method is a method of forming the pellet-shaped positive electrode mixture layer 1B and negative electrode mixture layer 2B by pressing a positive electrode mixture disposed on one surface of the solid electrolyte material and a negative electrode mixture disposed on the other surface using a pellet manufacturing jig having a cylindrical holder (die), an upper punch, and a lower punch that can be inserted into the cylindrical holder. Specifically, the solid electrolyte material is inserted into the cylindrical holder. Next, after a negative electrode mixture is put on one surface of the solid electrolyte material, the lower punch is inserted on the negative electrode mixture. Next, the orientation of the solid electrolyte material is reversed, and after a positive electrode mixture is put on the other surface of the solid electrolyte material, the upper punch is inserted on the positive electrode mixture. Then, the pellet manufacturing jig is placed on a press, and by pressing the lower punch and the upper punch, the pellet-shaped positive electrode mixture layer 1B and negative electrode mixture layer 2B can be manufactured.

[0070] The coating method is a method of forming a film-like negative electrode mixture layer 2B by applying a negative electrode mixture coating liquid to one surface of a solid electrolyte material and drying it, and forming a film-like positive electrode mixture layer 1B by applying a positive electrode mixture coating liquid to the other surface of the solid electrolyte material and drying it. Specifically, a negative electrode mixture coating liquid is obtained by mixing a negative electrode mixture and a solvent, and a positive electrode mixture coating liquid is obtained by mixing a positive electrode mixture and a solvent. Next, the negative electrode mixture coating liquid is applied to one surface of the solid electrolyte material using a coating device such as a bar coater, and then dried to form a film-like negative electrode mixture layer 2B. Next, the orientation of the solid electrolyte material is reversed, and the positive electrode mixture coating liquid is similarly applied to the other surface of the solid electrolyte material, and then dried to form a film-like positive electrode mixture layer 1B.

[0071] The pressure bonding method is a method of preparing a solid electrolyte material, a film-like positive electrode mixture, and a film-like negative electrode mixture, respectively, laminating a film-like positive electrode mixture layer 1B on one surface of the solid electrolyte material and a film-like negative electrode mixture layer 2B on the other surface, and pressing and pressure bonding the obtained laminate.

[0072] In this way, a laminate in which the positive electrode mixture layer 1B, the solid electrolyte layer 3, and the negative electrode mixture layer 2B are laminated in this order is obtained. By pressure bonding a positive electrode current collector 1A to the surface of the positive electrode mixture layer 1B of the obtained laminate and a negative electrode current collector 2A to the surface of the negative electrode mixture layer 2B, respectively, a laminate in which the positive electrode 1, the solid electrolyte layer 3, and the negative electrode 2 are laminated in this order is obtained. Next, external terminals are welded to the positive electrode current collector 1A of the positive electrode 1 and the negative electrode current collector 2A of the negative electrode 2 that form the obtained laminate by known methods, respectively, to electrically connect the positive electrode current collector 1A or the negative electrode current collector 2A and the external terminals. Then, the laminate connected to the external terminals is housed in an outer package, and the opening of the outer package is heat-sealed to seal it. Through the above steps, the all-solid-state battery 10 of the present embodiment is obtained.

[0073] In the all-solid-state battery 10 of the present embodiment configured as described above, since the solid electrolyte layer 3 is the above solid electrolyte material, the rate characteristics are improved.

[0074] As described above, the embodiments of the present invention have been described in detail with reference to the drawings. However, each configuration and their combinations in each embodiment are examples, and additions, omissions, substitutions, and other changes to the configuration are possible without departing from the spirit of the present invention.

Example

[0075] [Example 1] (1) Preparation of solid electrolyte Lithium chloride (LiCl) and zirconium chloride (ZrCl4) were mixed at a molar ratio of 2:1 (= LiCl:ZrCl4) to obtain a raw material powder mixture. The raw material powder mixture was mixed and reacted for 24 hours using a planetary ball mill apparatus at a rotation speed of 500 rpm for self-rotation and 500 rpm for revolution, with the rotation directions of self-rotation and revolution being opposite to each other to produce a solid electrolyte (Li2ZrCl6). Note that a sealed container and balls for the planetary ball mill were made of zirconia.

[0076] (2) Preparation of negative electrode mixture Lithium titanate (Li4Ti5O 12 , LTO), the solid electrolyte (Li2ZrCl6) obtained in (1) above, and graphite (C) were weighed at a volume ratio of 4:5:1 (= LTO:Li2ZrCl6:C), and mixed for 15 minutes using an agate mortar and pestle to obtain a negative electrode mixture.

[0077] (3) Preparation of positive electrode mixture Lithium cobalt oxide (LiCoO2), the solid electrolyte (Li2ZrCl6) obtained in (1) above, and graphite (C) were weighed at a volume ratio of 4:5:1 (= LiCoO2:Li2ZrCl6:C), and mixed for 15 minutes using an agate mortar and pestle to obtain a positive electrode mixture.

[0078] (4) Preparation of solid electrolyte pellet The solid electrolyte (Li2ZrCl6) obtained in (1) above was used to fabricate a solid electrolyte pellet with a diameter of 10 mm as follows using a pellet manufacturing jig. The pellet manufacturing jig has a resin holder with a diameter of 10 mm, an upper punch and a lower punch with a diameter of 9.99 mm. The material of the upper and lower punches is die steel (SKD material). The lower punch was inserted into the resin holder of the pellet manufacturing jig, and the solid electrolyte was poured onto the lower punch. Next, the upper punch was inserted onto the solid electrolyte. This pellet manufacturing jig was placed on a press and pressurized at a molding pressure of 24 tons. The pellet manufacturing jig was taken out of the press, and the solid electrolyte pellet was taken out of the pellet manufacturing jig.

[0079] The solid electrolyte pellet was placed on an aluminum sample stage and introduced into an electron beam irradiation device. The electron beam irradiation device was evacuated, and when the degree of vacuum reached a predetermined value (5×10 -3 Pa), electron beam irradiation was performed under the conditions of a voltage of 5 kV, a current of 500 pA, and a processing time of 20 seconds to roughen one surface of the solid electrolyte pellet. After the roughening treatment, the solid electrolyte pellet was taken out of the electron beam irradiation device, inverted, placed on the aluminum sample stage, and the other surface of the solid electrolyte pellet was roughened.

[0080] (5) Fabrication of all-solid-state battery The solid electrolyte pellet obtained in (4) above was inserted into the resin holder of the pellet manufacturing jig. The negative electrode mixture obtained in (2) above was poured onto one surface of the solid electrolyte pellet. The resin holder was vibrated to level the surface of the negative electrode mixture, and then the lower punch was inserted onto the negative electrode mixture to smooth the surface of the negative electrode mixture. Next, the orientation of the solid electrolyte pellet was reversed, the positive electrode mixture obtained in (3) above was poured onto the other surface of the solid electrolyte pellet, and in the same manner as the above negative electrode mixture, after leveling the surface of the positive electrode mixture, the upper punch was inserted onto the positive electrode mixture to smooth the surface of the positive electrode mixture. This pellet manufacturing jig was placed on a press and pressurized at a molding pressure of 24 tons to obtain a laminate in which the negative electrode mixture pellet, the solid electrolyte pellet, and the positive electrode mixture pellet were laminated in this order. The obtained laminate had a diameter of 10 mm and a thickness of 450 μm.

[0081] An insulating resin sheet (20 mm in length × 30 mm in width × 300 μm in thickness) having a through-hole with a diameter of 11 mm at the center was prepared. A laminate was inserted into the through-hole of this insulating resin sheet such that the positive electrode mixture layer was exposed on one surface of the insulating resin sheet and the negative electrode mixture layer was exposed on the other surface. Next, an aluminum foil (positive electrode current collector) was placed on the surface of the positive electrode mixture layer of the laminate, and an aluminum foil (negative electrode current collector) was placed on the surface of the negative electrode mixture layer, respectively. The positive electrode current collector and the negative electrode current collector were fixed to the insulating resin sheet with an adhesive tape to fabricate a solid-state battery cell. Terminals were attached to the positive electrode current collector and the negative electrode current collector of the obtained solid-state battery cell, and the solid-state battery cell was housed in an aluminum laminate bag such that the terminals were exposed. The aluminum laminate bag was sealed to fabricate an all-solid-state battery. The fabrication of the all-solid-state battery was carried out in a glove box under an argon gas atmosphere with a dew point of -70°C.

[0082] (6) Evaluation For the solid electrolyte pellet, surface observation and the surface ten-point average roughness Rz JIS were carried out by the following method. Also, the rate characteristics of the all-solid-state battery were measured by the following method. The surface ten-point average roughness Rz JIS and the measurement results of the rate characteristics are shown in Table 1.

[0083] (Surface Observation) The surface of the solid electrolyte pellet was observed using an SEM (scanning electron microscope). Figure 2 shows the SEM photograph of the surface of the solid electrolyte pellet after the roughening treatment, and Figure 3 shows the SEM photograph of the surface of the solid electrolyte pellet before the roughening treatment.

[0084] (Surface Ten-Point Average Roughness Rz of the Solid Electrolyte Pellet JIS ) The solid electrolyte pellet was cut, the cut surface was polished, and then processed by argon ion milling to prepare a sample for cross-sectional observation. The obtained sample was observed using an SEM (scanning electron microscope) to obtain a roughness curve of the cross-section. From the obtained roughness curve, the average value of the absolute values of the elevations of the peaks from the highest peak to the fifth peak and the average value of the absolute values of the elevations of the valleys from the lowest valley to the fifth valley were calculated, and the obtained value was defined as the surface ten-point average roughness Rz JIS was used. The surface ten-point average roughness Rz JIS was measured six times, three times each for the upper punch side surface and the lower punch side surface of the solid electrolyte pellet. The surface ten-point average roughness Rz JIS described in Table 1 is the average value of the surface ten-point average roughness Rz JIS measured six times.

[0085] (Rate characteristics of all-solid-state battery) Charge and discharge were performed under the following conditions. The voltage range was from 2.8 V to 1.3 V. Charging was performed at a constant current of 0.1C, and after reaching the constant voltage, charging was terminated when the current reached 0.05C equivalent. Discharging was performed at 0.1C and 1.0C. The ratio of the discharge capacity at 1.0C to the discharge capacity at 0.1C was defined as the rate characteristic (%). Also, for the results of the rate characteristics, when the ratio of the discharge capacity at 1.0C to the discharge capacity at 0.1C (discharge capacity at 1.0C / discharge capacity at 0.1C) was 0.8 or more, it was judged as "◎", when it was 0.7 or more and less than 0.8, it was judged as "〇", and when it was less than 0.7, it was judged as "×". The charge and discharge test was performed in a constant temperature bath at 25°C.

[0086] [Examples 2, 3, Comparative Examples 1, 2] (4) In the production of the solid electrolyte pellet, except that the conditions of the voltage, current, and treatment time for the roughening treatment were the conditions described in Table 1 below, an all-solid-state battery was produced in the same manner as in Example 1, and the surface ten-point average roughness Rz JIS of the solid electrolyte pellet and the rate characteristics of the all-solid-state battery were measured. The results are shown in Table 1.

[0087] [Examples 4 - 6] (1) In the production of the solid electrolyte, lithium sulfate (Li2SO4) and zirconium chloride (ZrCl4) were mixed and reacted at a molar ratio of 1:1 (=Li2SO4:ZrCl4) to produce Li2ZrSO4Cl4. Then, (2) in the preparation of the negative electrode mixture and (3) in the preparation of the positive electrode mixture, Li2ZrSO4Cl4 was used as the solid electrolyte. Furthermore, (4) in the preparation of the solid electrolyte pellet, Li2ZrSO4Cl4 was used as the solid electrolyte, and the conditions of the voltage, current, and treatment time for the roughening treatment were set as the conditions described in Table 1 below. Except for the above, a all-solid-state battery was produced in the same manner as in Example 1, and the surface ten-point average roughness Rz of the solid electrolyte pellet JIS and the rate characteristics of the all-solid-state battery were measured. The results are shown in Table 1.

[0088] [Examples 7 to 9] (1) In the production of the solid electrolyte, lithium chloride (LiCl) and yttrium chloride (YCl3) were mixed and reacted at a molar ratio of 3:1 (=LiCl:YCl3) to produce Li3YCl6. Then, (2) in the preparation of the negative electrode mixture and (3) in the preparation of the positive electrode mixture, Li3YCl6 was used as the solid electrolyte. Furthermore, (4) in the preparation of the solid electrolyte pellet, Li3YCl6 was used as the solid electrolyte, and the conditions of the voltage, current, and treatment time for the roughening treatment were set as the conditions described in Table 1 below. Except for the above, a all-solid-state battery was produced in the same manner as in Example 1, and the surface ten-point average roughness Rz of the solid electrolyte pellet JIS and the rate characteristics of the all-solid-state battery were measured. The results are shown in Table 1.

[0089] [Examples 10 to 12] (1) In the production of the solid electrolyte, lithium chloride (LiCl), aluminum chloride (AlCl3), and zirconium chloride (ZrCl4) were mixed and reacted at a molar ratio of 2.3:0.3:0.7 (=LiCl:AlCl3:ZrCl4) to produce Li 2.3 Al 0.3 Zr 0.7 Cl6. Then, (2) in the preparation of the negative electrode mixture and (3) in the preparation of the positive electrode mixture, Li 2.3Al 0.3 Zr 0.7 Cl6 was used. Further, in the production of the solid electrolyte pellet, Li 2.3 Al 0.3 Zr 0.7 Cl6 was used, and the conditions of the voltage, current, and treatment time for the roughening treatment were set as the conditions described in Table 1 below. Except for the above, in the same manner as in Example 1, an all-solid-state battery was fabricated, and the surface ten-point average roughness Rz JIS of the solid electrolyte pellet and the rate characteristics of the all-solid-state battery were measured. The results are shown in Table 1.

[0090] [Examples 13 to 15] (1) In the production of the solid electrolyte, lithium chloride (LiCl), zirconium chloride (ZrCl4), and silicon dioxide (SiO2) were mixed and reacted at a molar ratio of 2:1:2 (=LiCl:ZrCl4:SiO2) to produce Li2Zr(SiO2)2Cl6. Then, (2) in the production of the negative electrode mixture and (3) in the production of the positive electrode mixture, Li2Zr(SiO2)2Cl6 was used as the solid electrolyte. Further, (4) in the production of the solid electrolyte pellet, Li2Zr(SiO2)2Cl6 was used as the solid electrolyte, and the conditions of the voltage, current, and treatment time for the roughening treatment were set as the conditions described in Table 1 below. Except for the above, in the same manner as in Example 1, an all-solid-state battery was fabricated, and the surface ten-point average roughness Rz JIS of the solid electrolyte pellet and the rate characteristics of the all-solid-state battery were measured. The results are shown in Table 1.

[0091] [Comparative Examples 3 to 5] (2) In the production of the negative electrode mixture and (3) in the production of the positive electrode mixture, Li 1.3 Al 0.3 Ti 1.7 (PO4)3 was used. Further, (4) in the production of the solid electrolyte pellet, Li 1.3 Al 0.3 Ti 1.7(PO4)3 was used, and the conditions of voltage, current, and treatment time for the roughening treatment were set as those described in Table 1 below. Except for the above, a all-solid-state battery was fabricated in the same manner as in Example 1, and the surface ten-point average roughness Rz of the solid electrolyte pellet JIS and the rate characteristics of the all-solid-state battery were measured. The results are shown in Table 1.

[0092]

Table 1

[0093] From the SEM photographs in FIGS. 2 and 3, it can be seen that a large number of irregularities are formed on the surface of the solid electrolyte pellet by roughening the solid electrolyte pellet.

[0094] From the results in Table 1, the surface ten-point average roughness Rz JIS For the all-solid-state batteries of Examples 1 to 3 using pellets of the halide-based solid electrolyte (Li2ZrCl6) within the scope of the present invention, the surface ten-point average roughness Rz JIS It can be seen that the rate characteristics are improved compared to the all-solid-state batteries of Comparative Examples 1 and 2 using solid electrolyte pellets outside the scope of the present invention. Also, from the results of Examples 4 to 6, it was confirmed that for Li2ZrSO4Cl4 as well, when the surface ten-point average roughness Rz JIS is within the scope of the present invention, the rate characteristics of the all-solid-state battery are improved. Furthermore, from the results of Comparative Examples 3 to 4, for the oxide-based solid electrolyte Li 1.3 Al 0.3 Ti 1.7 (PO4)3, it was confirmed that even when the surface ten-point average roughness Rz JIS is within the scope of the present invention, the rate characteristics of the all-solid-state battery are inferior.

[0095] [Examples 16 to 18, Comparative Examples 6, 7] (2) Preparation of the negative electrode composite and (3) preparation of the positive electrode composite used Li6PS5Cl as the solid electrolyte. Further, in (4) preparation of the solid electrolyte pellet, Li6PS5Cl was used as the solid electrolyte, and the voltage, current, and treatment time conditions for the roughening treatment were set to the conditions described in Table 2 below. Except for the above, a all-solid-state battery was fabricated in the same manner as in Example 1, and the surface ten-point average roughness Rz of the solid electrolyte pellet JIS and the rate characteristics of the all-solid-state battery were measured. The results are shown in Table 2.

[0096] [Examples 19 to 21] (2) Preparation of the negative electrode composite and (3) preparation of the positive electrode composite used Li7P3S 11 as the solid electrolyte. Further, in (4) preparation of the solid electrolyte pellet, Li7P3S 11 was used as the solid electrolyte, and the voltage, current, and treatment time conditions for the roughening treatment were set to the conditions described in Table 2 below. Except for the above, a all-solid-state battery was fabricated in the same manner as in Example 1, and the surface ten-point average roughness Rz of the solid electrolyte pellet JIS and the rate characteristics of the all-solid-state battery were measured. The results are shown in Table 2.

[0097] [Table 2]

[0098] From the results in Table 2, it can be seen that the all-solid-state batteries of Examples 7 to 9 using pellets of the sulfide-based solid electrolyte (Li6PS5Cl) with the surface ten-point average roughness Rz JIS within the scope of the present invention have improved rate characteristics compared to the all-solid-state batteries of Comparative Examples 6 and 7 using sulfide-based solid electrolyte pellets with the surface ten-point average roughness Rz JIS outside the scope of the present invention. Also, from the results of Examples 10 to 12, it was confirmed that for Li7P3S 11 as well, when the surface ten-point average roughness Rz JIS is within the scope of the present invention, the rate characteristics of the all-solid-state battery are improved. [Explanation of Reference Signs]

[0099] 1... positive electrode, 1A... positive electrode current collector, 1B... positive electrode mixture layer, 2... negative electrode, 2A... negative electrode current collector, 2B... negative electrode mixture layer, 3... solid electrolyte layer, 10... all-solid-state battery.

Claims

Claim 1 A solid electrolyte material having a pair of mutually facing surfaces and containing at least one of a halide-based solid electrolyte or a sulfide-based solid electrolyte represented by the following formula (1): At least one of the pair of surfaces has a surface ten-point average roughness Rz ＪＩＳ in the range of 20 nm or more and 1500 nm or less, The sulfide-based solid electrolyte is a compound containing Li, S, and Si, or a compound represented by the following formula (2). The solid electrolyte material. Li ２＋ａ E １－ｂ G ｂ D ｃ X ｄ ...(1) LiqMrPsOtXuSv... (2) (In formula (1), E is at least one element selected from the group consisting of Al, Sc, Y, Zr, Hf, and lanthanoids; G is at least one element selected from the group consisting of Na, K, Rb, Cs, Mg, Ca, Sr, Ba, B, Si, Ti, Cu, Nb, Ag, In, Sn, Sb, Ta, W, Au, and Bi; D is CO ３ , SO ４ , BO ３ , PO ４ , NO ３ , SiO ３ , OH, O ２ , and is at least one group selected from the group consisting of; X is at least one selected from the group consisting of F, Cl, Br, and I; 0 ≦ a < 1.5, 0 ≦ b < 0.5, 0 ≦ c ≦ 5, 0 < d ≦ 6.1.) In formula (2), M is a tetravalent metal, X is at least one element selected from the group consisting of F, Cl, Br, and I, 1 ≤ q ≤ 20, 0 ≤ r ≤ 2, 1 ≤ s ≤ 5, 0 ≤ t ≤ 5, 0 ≤ u ≤ 5, and v = q / 2 + 2×r + 2.5×s - t - u / 2.) Claim 2 The solid electrolyte material according to claim 1, wherein the solid electrolyte material has an average thickness of 2.0 μm or more. Claim 3 An all-solid-state battery comprising the solid electrolyte material according to claim 1 or 2, a positive electrode mixture layer in contact with one of the pair of surfaces of the solid electrolyte material, and a negative electrode mixture layer in contact with the other of the pair of surfaces of the solid electrolyte material.

Images