All-solid-state battery

Abstract

The purpose of the present invention is to provide a means capable of improving rate characteristics in a lithium deposition type all-solid-state battery. According to the present invention, an all-solid-state battery is provided with a power generation element having: a positive electrode having a positive electrode active material layer containing a positive electrode active material; a negative electrode which has a negative electrode current collector and on which lithium metal is deposited during charging; a solid electrolyte layer that is interposed between the positive electrode and the negative electrode and contains a first solid electrolyte; the all-solid-state battery is characterized in that a negative electrode intermediate layer is arranged between the solid-state electrolyte layer and the negative electrode, the negative electrode intermediate layer is composed of a negative electrode intermediate layer constituent material, the negative electrode intermediate layer constituent material contains at least one material selected from the group consisting of carbon materials into which lithium ions can be embedded, and the all-solid-state battery is also provided with a mixed layer, and a mixed layer that is adjacent to each of the main surface of the solid electrolyte layer facing the negative electrode intermediate layer and the main surface of the negative electrode intermediate layer facing the solid electrolyte layer, the mixed layer containing a mixed layer constituent material. The mixed layer constituent material contains at least one selected from the group consisting of a second solid electrolyte and a carbon material into which lithium ions can be embedded.

Description

Technical Field

[0001] This invention relates to all-solid-state batteries. Background Technology

[0002] In recent years, there has been a surge in research and development of all-solid-state batteries using oxide-based and sulfide-based solid electrolytes. Solid-state electrolytes are primarily composed of ion conductors capable of ion conduction in a solid state. Therefore, all-solid-state batteries, in principle, do not suffer from the various problems caused by flammable organic electrolytes that are present in traditional liquid-based secondary batteries using non-aqueous electrolytes. Furthermore, generally speaking, using high-potential, high-capacity positive electrode materials and high-capacity negative electrode materials can significantly improve the battery's output density and energy density.

[0003] In a typical all-solid-state battery, a positive electrode with a positive active material layer, a solid electrolyte layer containing a solid electrolyte, and a negative electrode with a negative active material layer are stacked sequentially. To obtain good battery characteristics, reducing the interfacial resistance between the positive and / or negative active material layers and the solid electrolyte layer is crucial.

[0004] For example, Japanese Patent Application Publication No. 2008-135287 discloses a method for disposing a thin film layer between the electrode active material layer and the solid electrolyte layer in an all-solid-state battery. This thin film layer is composed of a solid electrolyte contained in the solid electrolyte layer and an electrode active material contained in the electrode active material layer. This increases the contact and bonding area between the electrode active material layer and the solid electrolyte layer, thereby reducing the interfacial resistance and resulting in excellent battery characteristics. Summary of the Invention

[0005] As a type of all-solid-state lithium secondary battery (all-solid-state battery) that uses lithium metal as the negative electrode active material, there is a known lithium deposition type battery in which lithium metal is deposited on the negative electrode current collector during charging. In the charging process of such a lithium deposition type all-solid-state battery, lithium metal is deposited between the solid electrolyte layer and the negative electrode current collector.

[0006] However, according to the inventors' research based on the present invention, it has been determined that if the technology described in Japanese Patent Application Publication No. 2008-135287 is applied to lithium deposition type all-solid-state batteries, there is a problem that sufficient rate performance cannot be obtained.

[0007] Therefore, the object of the present invention is to provide a means to improve rate performance in lithium deposition type all-solid-state batteries.

[0008] The inventors of this invention conducted in-depth research to solve the aforementioned technical problems. As a result, they discovered that by configuring a negative electrode intermediate layer containing carbon material between the solid electrolyte layer and the negative electrode active material layer, and by providing a mixed layer in contact with these layers between the solid electrolyte layer and the negative electrode intermediate layer, and by making this mixed layer simultaneously contain both solid electrolyte and carbon material, the aforementioned technical problems can be solved, thus completing this invention.

[0009] That is, one embodiment of the present invention is an all-solid-state battery comprising a power generation element having: a positive electrode having a positive electrode active material layer containing a positive electrode active material; a negative electrode having a negative electrode current collector on which lithium metal is deposited during charging; a solid electrolyte layer between the positive electrode and the negative electrode, containing a first solid electrolyte; and a negative electrode intermediate layer disposed between the solid electrolyte layer and the negative electrode, the negative electrode intermediate layer being composed of a negative electrode intermediate layer constituent material containing at least one selected from the group consisting of carbon materials capable of lithium-ion intercalation. The all-solid-state battery further comprises a hybrid layer adjacent to the main surface of the solid electrolyte layer opposite to the negative electrode intermediate layer and the main surface of the negative electrode intermediate layer opposite to the solid electrolyte layer, respectively. The hybrid layer comprises a hybrid layer constituent material containing at least one selected from the group consisting of a second solid electrolyte and carbon materials capable of lithium-ion intercalation. Attached Figure Description

[0010] Figure 1 This is a cross-sectional view schematically illustrating the overall structure of a stacked (internal parallel connection type) all-solid-state lithium secondary battery (stacked secondary battery) according to an embodiment of the present invention. Detailed Implementation

[0011] One embodiment of the present invention is an all-solid-state battery comprising a power generation element having: a positive electrode having a positive active material layer containing a positive active material; a negative electrode having a negative current collector on which lithium metal is deposited during charging; a solid electrolyte layer disposed between the positive electrode and the negative electrode, containing a first solid electrolyte; and a negative electrode intermediate layer disposed between the solid electrolyte layer and the negative electrode, the negative electrode intermediate layer being composed of a negative electrode intermediate layer constituent material containing at least one selected from the group consisting of carbon materials suitable for lithium-ion intercalation. The all-solid-state battery further comprises a hybrid layer adjacent to the main surface of the solid electrolyte layer opposite the negative electrode intermediate layer and the main surface of the negative electrode intermediate layer opposite the solid electrolyte layer, respectively. The hybrid layer comprises a hybrid layer constituent material containing at least one selected from the group consisting of a second solid electrolyte and carbon materials suitable for lithium-ion intercalation. According to this embodiment of the all-solid-state battery, in a lithium deposition type all-solid-state battery, rate performance can be improved.

[0012] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that in the description of the drawings, the same reference numerals are used to denote the same elements, and repeated descriptions are omitted. Furthermore, the dimensions in the drawings may be exaggerated for ease of explanation and differ from the actual proportions.

[0013] Figure 1 This is a schematic cross-sectional view illustrating the overall structure of a stacked (internal parallel connection type) all-solid-state lithium secondary battery (hereinafter also simply referred to as "stacked secondary battery") according to an embodiment of the present invention. It should be noted that... Figure 1 This shows a cross-section of a stacked secondary battery during charging. Figure 1 The stacked secondary battery 10a shown has a structure in which a generally rectangular power generation element 21, which actually performs the charge and discharge reaction, is sealed inside the battery casing, i.e., the laminate 29. Here, the power generation element 21 has a structure in which a negative electrode, a solid electrolyte layer 17, and a positive electrode are stacked. The negative electrode has a structure in which a negative electrode current collector 11' and a negative electrode active material layer 13 composed of lithium metal deposited on the surface of the negative electrode current collector 11' are stacked. Moreover, a negative electrode intermediate layer 14 is disposed on the surface of the negative electrode active material layer 13, and a mixed layer 16 is disposed in contact with the negative electrode intermediate layer 14 and the solid electrolyte layer 17, respectively. The positive electrode has a structure in which a positive electrode active material layer 15 is disposed on the surface of the positive electrode current collector 11'. Thus, the negative electrode current collector 11', the negative electrode active material layer 13, the negative electrode intermediate layer 14, the mixed layer 16, the solid electrolyte layer 17, the positive electrode active material layer 15, and the positive electrode current collector 11' constitute a single cell layer 19. Therefore, Figure 1The stacked secondary battery 10a shown can be described as having a structure in which multiple single cell layers 19 are connected in parallel. A negative current collector 25 and a positive current collector 27, respectively connected to the respective electrodes (negative and positive), are mounted on the negative current collector 11' and the positive current collector 11" and are led out of the laminated film 29 in a manner sandwiched between the ends of the laminated film 29. A pressure (not shown) is applied to the stacked secondary battery 10a in the stacking direction of the power generation element 21 by a pressure-applying component. Therefore, the volume of the power generation element 21 remains constant.

[0014] The main components of the all-solid-state battery of this embodiment will be described below.

[0015] [Current Collector] The current collector (negative electrode current collector, positive electrode current collector) serves as the medium for electron movement from the electrode active material layers (negative electrode active material layer, positive electrode active material layer). There are no particular limitations on the materials constituting the current collector. For example, metals such as aluminum, nickel, iron, stainless steel, titanium, and copper, or conductive resins can be used as constituent materials. There are also no particular limitations on the thickness of the current collector; as an example, it ranges from 10 μm to 100 μm.

[0016] [Negative electrode active material layer] The all-solid-state battery of this embodiment is a so-called lithium deposition type battery in which lithium metal is deposited on the negative electrode current collector during charging. The layer composed of lithium metal deposited on the negative electrode current collector during this charging process is the negative electrode active material layer of the all-solid-state battery of this embodiment. Therefore, the thickness of the negative electrode active material layer increases as the charging process progresses and decreases as the discharging process progresses. The negative electrode active material layer may not exist during complete discharge, but depending on the circumstances, a negative electrode active material layer composed of a certain amount of lithium metal may be provided during complete discharge. Furthermore, the thickness of the negative electrode active material layer (lithium metal layer) during complete charging is not particularly limited, and is typically 0.1 to 1000 μm. In one embodiment, the all-solid-state battery is a fully deposited type battery in which no negative electrode active material layer exists during complete discharge.

[0017] [Solid electrolyte layer] The solid electrolyte layer is located between the positive electrode active material layer and the negative electrode active material layer, and contains a solid electrolyte (usually as the main component). It should be noted that in this specification, the solid electrolyte contained in the solid electrolyte layer is referred to as the "first solid electrolyte," and the solid electrolyte contained in the mixed layer (described later) is referred to as the "second solid electrolyte." Therefore, the designations "first" and "second" are meaningless in themselves; these terms are merely used to distinguish the location where the solid electrolyte exists. There are no particular limitations on the solid electrolyte (first solid electrolyte) contained in the solid electrolyte layer, and materials known in the art can be appropriately used. Examples of solid electrolytes include sulfide solid electrolytes and oxide solid electrolytes. It should be noted that in this specification, a solid electrolyte refers to a material mainly composed of an ion conductor capable of ion conduction in a solid state, specifically one with a lithium-ion conductivity of 1×10⁻⁶ at room temperature (25°C). －5 For materials with a S / cm or higher, the lithium-ion conductivity is preferably 1×10⁻⁶. －4 S / cm or higher. Here, the ionic conductivity value can be determined by electrochemical impedance spectroscopy.

[0018] From the viewpoint of exhibiting excellent lithium-ion conductivity and being able to further track the volume change of the electrode active material during charging and discharging, the solid electrolyte is preferably a sulfide solid electrolyte containing sulfur (S), more preferably a sulfide solid electrolyte containing lithium (Li), methyl sulfide (M), and sulfur (S), wherein the M element is a sulfide solid electrolyte containing at least one element selected from the group consisting of p, niobium (Si), ge, sn, ti, zirconium (Zr), nb, al, sb, br, chlorine (Cl), and i, and even more preferably a sulfide solid electrolyte containing sulfur (S), limonium (Li), and p, or a sulfide solid electrolyte containing sulfur (S), limonium (Li), ge, and p. In lithium deposition type all-solid-state batteries, higher performance batteries can be obtained by using sulfide solid electrolytes containing sulfur (S), limonium (Li), and p, or sulfide solid electrolytes containing sulfur (S), limonium (Li), ge, and p.

[0019] Sulfide solid electrolytes can have a Li3PS4 framework, a Li4P2S7 framework, or a Li4P2S6 framework. Examples of sulfide solid electrolytes with a Li3PS4 framework include LiI-Li3PS4, LiI-LiBr-Li3PS4, and Li3PS4. Examples of sulfide solid electrolytes with a Li4P2S7 framework include Li-P-S based solid electrolytes known as LPS. Furthermore, sulfide solid electrolytes can be made from Li... （4－x） Ge （1－x） P xS4 (where x satisfies 0 < x < 1) represents LGPS, etc. More specifically, examples include LPS (Li2S-P2S5), Li7P3S, etc. 11 Li 3.2 P 0.96 S, Li 3.25 Ge 0.25 P 0.75 S4, Li 10 GeP2S 12 Or Li6PS5X (here, X is Cl, Br, or I), etc. It should be noted that the description of "Li2S-P2S5" refers to a sulfide solid electrolyte constructed using a raw material composition containing Li2S and P2S5, and the same applies to other descriptions. Sulfide solid electrolytes have high ionic conductivity and low bulk modulus; therefore, from the viewpoint of being able to track the volume change of the electrode active material accompanying charge and discharge, LPS (Li2S-P2S5), Li6PS5X (here, X is Cl, Br, or I), and Li7P3S are preferred. 11 Li 3.2 P 0.96 The group consists of S and Li3PS4.

[0020] Examples of solid electrolyte shapes include spherical, ellipsoidal, and other particulate or thin-film forms. When the solid electrolyte is in particulate form, its average particle size (D50) is not particularly limited, but is preferably 0.01 μm or more and 40 μm or less, more preferably 0.1 μm or more and 20 μm or less, and even more preferably 0.1 μm or more and 10 μm or less.

[0021] The content of solid electrolyte (first solid electrolyte) in the solid electrolyte layer is preferably 50-100% by mass, more preferably 90-100% by mass.

[0022] In addition to the solid electrolyte (first solid electrolyte), the solid electrolyte layer may also contain a binder. There are no particular limitations on the binder, and known binders may be used appropriately. Examples of binders include polyvinylidene fluoride (PVDF), compounds in which the hydrogen atoms of PVDF are replaced by other halogen elements, polytetrafluoroethylene (PTFE), styrene-butadiene rubber (SBR), and carboxymethyl cellulose (CMC). Preferably, the binder contains polyvinylidene fluoride (PVDF), and more preferably, polyvinylidene fluoride (PVDF).

[0023] The thickness of the solid electrolyte layer varies depending on the structure of the target all-solid-state battery, and is typically 0.1 to 1000 μm, preferably 10 to 100 μm.

[0024] [Negative electrode intermediate layer] In the all-solid-state battery of this embodiment, a negative electrode interlayer containing a carbon material suitable for lithium-ion intercalation is provided on the surface of the negative electrode current collector side of the hybrid layer (described later). This suppresses dendrite growth from the lithium metal layer during charging when lithium metal is deposited between the negative electrode interlayer and the negative electrode current collector, preventing short circuits and the resulting capacity reduction. Furthermore, it does not hinder the battery reaction, preventing degradation of the solid electrolyte and capacity reduction caused by the reaction of deposited lithium metal with the solid electrolyte.

[0025] It should be noted that the negative electrode intermediate layer preferably has conductivity as a whole. The volume resistivity of the negative electrode intermediate layer is not particularly limited, but is preferably 10. 2 The volume resistivity is less than Ω·cm, and more preferably less than 10 Ω·cm. In this specification, the volume resistivity of the negative electrode intermediate layer is the value measured using an electrode resistance measurement system (manufactured by Hioki Electric Co., Ltd., product name: RM2610).

[0026] The negative electrode interlayer is composed of a negative electrode interlayer material containing at least one carbon material selected from the group consisting of materials suitable for lithium-ion intercalation. By containing a carbon material suitable for lithium-ion intercalation in the negative electrode interlayer, the precipitation and growth of lithium dendrites can be suppressed. Specific examples of carbon materials suitable for lithium-ion intercalation include carbon black (specifically, acetylene black, Ketjen black, furnace black, channel black, pyrolytic carbon black, etc.), carbon nanotubes (CNTs), graphite, hard carbon, etc. Preferably, the carbon material contains at least one material selected from the group consisting of carbon black, and more preferably, it contains at least one material selected from the group consisting of acetylene black, Ketjen black, furnace black, channel black, and pyrolytic carbon black.

[0027] According to a preferred embodiment, the negative electrode intermediate layer includes at least one carbon particle as a constituent material of the negative electrode intermediate layer, and the carbon particle comprises the aforementioned carbon material available for lithium ion intercalation. Therefore, the effects of the present invention can be obtained more significantly.

[0028] The average particle size (average primary particle size) of the carbon particles is not particularly limited, for example, it is 200 nm or less, preferably 150 nm or less, and more preferably 100 nm or less. The lower limit of the average particle size of the carbon particles is not particularly limited, for example, it is 10 nm or more, preferably 15 nm or more, and more preferably 20 nm or more. It should be noted that, in this specification, the average particle size refers to the cumulative diameter (D50) of 50% of the particle size (the maximum distance between any two points on the observed particle outline) observed in several to dozens of fields of view when observing a cross-section of a particle-containing layer using a scanning electron microscope (SEM).

[0029] In the negative electrode interlayer, the material constituting the negative electrode interlayer preferably contains at least one metallic material in addition to at least one material selected from the group consisting of carbon materials suitable for lithium-ion intercalation. By further containing a metallic material in the negative electrode interlayer, lithium metal can be deposited more uniformly on the current collector surface. Specific examples of metallic materials include indium (In), aluminum (Al), silicon (Si), tin (Sn), magnesium (Mg), gold (Au), silver (Ag), zinc (Zn), nickel (Ni), copper (Cu), and alloys containing at least one of these. Preferably, the metallic material contains at least one material selected from the group consisting of In, Al, Si, Sn, Mg, Au, Ag, and Zn; more preferably, it contains at least one material selected from the group consisting of Ag, Mg, Zn, and Al; even more preferably, it contains at least one material selected from the group consisting of Ag, Mg, and Zn; and particularly preferably, it contains Ag.

[0030] According to a preferred embodiment, the negative electrode intermediate layer comprises: at least one carbon particle containing the aforementioned carbon material suitable for lithium-ion intercalation, and at least one metal particle containing the aforementioned metallic material. By using both carbon particles and metal particles to form the negative electrode intermediate layer, an all-solid-state battery with superior rate characteristics can be obtained.

[0031] When using both carbon particles and metal particles, the average particle size of the carbon particles is preferably within the range described above. The average particle size of the metal particles is, for example, 10–500 nm, preferably 20–300 nm, more preferably 30–200 nm, and even more preferably 40–100 nm. If the particle size is within the range described above, an all-solid-state battery with superior rate performance can be obtained.

[0032] When using both carbon particles and metal particles, the mass ratio of carbon particles to metal particles (carbon particles:metal particles) is not particularly limited, but is preferably 10:1 to 1:1, more preferably 5:1 to 2:1, and even more preferably 4:1 to 2.5:1. The volume ratio of carbon particles to metal particles (carbon particles:metal particles) is preferably 99:1 to 70:30, more preferably 95:5 to 75:25. When the mixing ratio (mass ratio or volume ratio) of carbon particles to metal particles is within the above range, an all-solid-state battery with superior rate characteristics can be obtained.

[0033] The negative electrode interlayer may further include a binder. There are no particular limitations on the type of binder; binders known in the art can be used, for example, the same binder exemplified as that used as a binder in a solid electrolyte layer. There are also no particular limitations on the amount of binder in the negative electrode interlayer.

[0034] The total amount of carbon and metal materials available for lithium-ion intercalation in the negative electrode intermediate layer is not particularly limited, but is preferably in the range of 80-100% by mass relative to 100% of the total solid components contained in the negative electrode intermediate layer, more preferably in the range of 90-100% by mass, even more preferably in the range of 95-100% by mass, and particularly preferably in the range of 98-100% by mass. This allows for a more significant attainment of the effects of the present invention.

[0035] It should be noted that the negative electrode intermediate layer preferably does not contain a solid electrolyte. In one embodiment, the negative electrode intermediate layer does not contain the solid electrolyte layer, the solid electrolyte contained in the mixed layer, or any other solid electrolyte. Because it does not contain a solid electrolyte, it is possible to suppress the deposited lithium metal from penetrating through the negative electrode intermediate layer to the solid electrolyte layer side, thereby further significantly preventing short circuits. In one embodiment, the content of the solid electrolyte in the negative electrode intermediate layer, converted from solid content, is, for example, 1% by mass or less, preferably 0.5% by mass or less, more preferably 0.1% by mass or less, even more preferably 0.05% by mass or less, and most preferably 0% by mass.

[0036] The thickness of the negative electrode interlayer is not particularly limited, but is preferably 1–20 μm, more preferably 2–18 μm, and even more preferably 5–15 μm. When the thickness of the negative electrode interlayer is within the above range, the precipitation and growth of lithium dendrites can be suppressed, and the decrease in energy density can be suppressed.

[0037] There are no particular restrictions on the method for manufacturing the negative electrode intermediate layer. For example, methods such as wet coating of the negative electrode intermediate layer constituent material or pressing the negative electrode intermediate layer constituent material into powder can be used.

[0038] [Hybrid Layer] In the all-solid-state battery of this embodiment, a hybrid layer is further provided, which is adjacent to the main surface of the solid electrolyte layer opposite to the negative electrode intermediate layer and the main surface of the negative electrode intermediate layer opposite to the solid electrolyte layer. The hybrid layer comprises a hybrid layer constituting material containing at least one selected from the group consisting of a solid electrolyte (second solid electrolyte) and a carbon material capable of lithium-ion intercalation. In one embodiment, the hybrid layer is composed of a hybrid layer constituting material containing at least one selected from the group consisting of a solid electrolyte (second solid electrolyte) and a carbon material capable of lithium-ion intercalation.

[0039] In lithium deposition-type all-solid-state batteries, lithium ions are supplied from the positive electrode side through a solid electrolyte layer during charging, and lithium metal is deposited on the surface of the negative electrode current collector to form a negative electrode active material layer. As described above, in the all-solid-state battery of this embodiment, a negative electrode interlayer is provided between the solid electrolyte layer and the negative electrode current collector. This negative electrode interlayer is composed of a negative electrode interlayer constituent material containing carbon material that can be used for lithium ion intercalation, thereby preventing short circuits in the battery and the resulting capacity reduction. However, it is known that if such a negative electrode interlayer is provided, the rate capability of the battery will decrease. This is believed to be because the layer interface created by providing the negative electrode interlayer tends to increase the resistance, and the reaction interface between the solid electrolyte and the negative electrode interlayer constituent material is mainly limited to the layer interface between the solid electrolyte layer and the negative electrode interlayer.

[0040] In contrast, in the all-solid-state battery of this embodiment, a hybrid layer comprising a hybrid layer material is disposed between the solid electrolyte layer and the negative electrode intermediate layer. This hybrid layer material includes both the solid electrolyte and a carbon material suitable for lithium-ion intercalation. This allows for the formation of a large number of reaction interfaces between the solid electrolyte and the carbon material in three dimensions, not only at the layer interface but also within the hybrid layer. It is believed that by increasing the contact area between the solid electrolyte and the carbon material per unit volume, the apparent current density decreases, and the rate characteristics improve. Furthermore, even if lithium deposition occurs within the hybrid layer, dendrite growth into the solid electrolyte layer can be suppressed by remaining within the hybrid layer, preventing short circuits and the resulting capacity reduction.

[0041] The solid electrolyte (second solid electrolyte) contained in the mixed layer can be the same as the first solid electrolyte and its preferred embodiment illustrated in the section on solid electrolyte layers described above. From the viewpoint of exhibiting excellent lithium-ion conductivity and being able to further track the volume change of the electrode active material during charging and discharging, a sulfide solid electrolyte containing sulfur (S), lithium (Li), and phosphorus (P) or a sulfide solid electrolyte containing sulfur (S), lithium (Li), ge (Ge), and phosphorus (P) is preferred. The solid electrolyte (second solid electrolyte) contained in the mixed layer can be the same type of material as the solid electrolyte (first solid electrolyte) contained in the solid electrolyte layer, or it can be a different material, but it is preferably the same type of material.

[0042] The carbon material contained in the hybrid layer that can be used for lithium-ion intercalation can also be the material and its preferred embodiment exemplified in the section on negative electrode intermediate layer. The carbon material contained in the hybrid layer that can be used for lithium-ion intercalation can be the same type of material as the carbon material contained in the negative electrode intermediate layer, or it can be a different material, but it is preferred to be the same type of material.

[0043] In the hybrid layer, as a constituent material, it is preferable to contain at least one metallic material in addition to at least one material selected from the group consisting of carbon materials suitable for lithium-ion intercalation. The metallic material contained in the hybrid layer can be the same material and preferred embodiment exemplified in the section on the negative electrode intermediate layer described above. The metallic material contained in the hybrid layer can be of the same type as the metallic material contained in the negative electrode intermediate layer, or it can be a different material; preferably, it is of the same type.

[0044] Preferably, at least one carbon particle containing a carbon material that can be intercalated into lithium ions, as described in the section on the negative electrode intermediate layer, and at least one metal particle containing a metallic material are used. When using both carbon particles and metal particles, the preferred embodiment exemplified in the section on the negative electrode intermediate layer can be adopted as a specific approach.

[0045] The hybrid layer may further include a binder. There are no particular limitations on the type of binder; binders known in the art can be used, for example, the same binder exemplified as that used in the solid electrolyte layer. There are also no particular limitations on the amount of binder in the hybrid layer. Furthermore, when a binder is included, the binder in the hybrid layer can be the same type of binder as that in the solid electrolyte layer or the negative electrode intermediate layer, or it can be a different binder.

[0046] The components of the hybrid layer constituting material, excluding the second solid electrolyte, can be made of the same type of material as the negative electrode intermediate layer constituting material, or they can be made of different materials, but it is preferred that they are made of the same type of material. In addition, the mixing ratio of the components other than the second solid electrolyte in the hybrid layer constituting material can be the same as or different from the mixing ratio of the components in the negative electrode intermediate layer constituting material.

[0047] The mass ratio of the second solid-state electrolyte to the total amount of carbon and metal materials available for lithium-ion intercalation in the hybrid layer material is not particularly limited, but is preferably 40:60 to 60:40, and more preferably 45:55 to 55:45. If the mass ratio of the second solid-state electrolyte to the total amount of carbon and metal materials is within the above range, the reaction interface between the second solid-state electrolyte and the carbon and metal materials can be increased more effectively. Therefore, an all-solid-state battery with superior rate characteristics can be obtained.

[0048] The concentration (mass%) of the second solid electrolyte in the mixed layer is not particularly limited, but it is preferably constant in the stacking direction of the power generation element, or decreases from the solid electrolyte layer side towards the negative electrode intermediate layer side in the stacking direction of the power generation element. This further increases the contact interface between the solid electrolyte and the carbon material (or carbon material and metal material), and further improves the rate characteristics.

[0049] More preferably, the concentration (mass%) of the second solid electrolyte in the hybrid layer decreases from the solid electrolyte layer side toward the negative electrode intermediate layer side in the stacking direction of the power generation element. In the hybrid layer, solid electrolyte particles or carbon material (or carbon material and metal material) particles can more easily achieve conductivity with each other. Therefore, when the concentration of the second solid electrolyte is high on the solid electrolyte layer side, the movement of lithium ions and electrons is easier, and the rate characteristics can be further improved.

[0050] Similarly, the total concentration (mass%) of carbon and metal materials available for lithium-ion intercalation in the hybrid layer is preferably constant in the stacking direction of the power generation element, or increases from the solid electrolyte layer side to the negative electrode intermediate layer side in the stacking direction of the power generation element, and more preferably increases from the solid electrolyte layer side to the negative electrode intermediate layer side in the stacking direction of the power generation element.

[0051] When the concentration (mass%) of the second solid electrolyte in the hybrid layer decreases from the solid electrolyte layer side toward the negative electrode intermediate layer side in the stacking direction of the power generation element, there is no particular limitation on the ratio of the concentration change to the thickness of the hybrid layer. In a preferred embodiment, the thickness of the hybrid layer is set as d, and the concentration of the second solid electrolyte in the hybrid layer is 70% by mass or more in the region from the interface with the solid electrolyte layer to 0.2d in the stacking direction of the power generation element, and 30% by mass or less in the region from the interface with the negative electrode intermediate layer to 0.2d. As a result, more solid electrolytes are in contact with each other at the interface with the solid electrolyte layer, and more carbon material (or carbon material and metal material) are in contact with each other at the interface with the negative electrode intermediate layer. Therefore, the resistance between the solid electrolyte layer and the hybrid layer, and between the hybrid layer and the negative electrode intermediate layer, can be further reduced, and the rate characteristics can be further improved. Furthermore, the concentration of the second solid electrolyte in the region from the interface with the solid electrolyte layer to 0.2d in the stacking direction of the power generation element is not particularly limited, for example, it is 99% by mass or less, preferably 95% by mass or less. Furthermore, in the stacking direction of the power generation element, the concentration of the second solid electrolyte in the region from the interface with the negative electrode intermediate layer to 0.2d is not particularly limited, for example, it is 1% by mass or more, preferably 5% by mass or more.

[0052] The hybrid layer can be composed of a single layer with uniform composition or a stack of multiple layers with different compositions. In a preferred embodiment, the concentration (mass%) of the second solid electrolyte decreases from the solid electrolyte layer side toward the negative electrode intermediate layer side in the stacking direction of the power generation element. Examples of such a hybrid layer include stacking multiple sub-hybrid layers with different mass ratios of the second solid electrolyte to carbon material and metal material. In this case, the sub-hybrid layers are configured such that the proportion (mass%) of the second solid electrolyte decreases from the solid electrolyte layer side toward the negative electrode intermediate layer side. The number of sub-hybrid layers is not particularly limited, for example, 2 to 5 layers.

[0053] When the mixing layer is formed by multiple sub-mixing layers, the concentration of the second solid electrolyte in each sub-mixing layer is not particularly limited as long as it is configured to be a value that decreases from the solid electrolyte layer side towards the negative electrode intermediate layer side. Preferably, it is 70% by mass or more in the sub-mixing layer closest to the solid electrolyte layer and 30% by mass or less in the sub-mixing layer closest to the negative electrode intermediate layer. This results in more solid electrolytes in contact with each other at the interface with the solid electrolyte layer and more carbon material (or carbon material and metal material) in contact with each other at the interface with the negative electrode intermediate layer. Therefore, the resistance between the solid electrolyte layer and the mixing layer, and between the mixing layer and the negative electrode intermediate layer, can be further reduced, and the rate characteristics can be further improved. It should be noted that the concentration of the second solid electrolyte in the sub-mixing layer closest to the solid electrolyte layer is not particularly limited, for example, it is 99% by mass or less, preferably 95% by mass or less. Similarly, the concentration of the second solid electrolyte in the sub-mixing layer closest to the negative electrode intermediate layer is not particularly limited, for example, it is 1% by mass or more, preferably 5% by mass or more.

[0054] In a preferred embodiment, the mixing layer is formed by stacking three sub-mixing layers. The concentrations of the second solid electrolyte in each sub-mixing layer, from the solid electrolyte layer side in the stacking direction of the power generation element, are 70–95% by mass, 40–60% by mass, and 5–30% by mass, respectively. This provides a sufficient concentration gradient, thus further improving the rate characteristics. Preferably, the total concentrations of carbon and metal materials in each sub-mixing layer are 5–30% by mass, 40–60% by mass, and 70–95% by mass, respectively, from the solid electrolyte layer side in the stacking direction of the power generation element.

[0055] It should be noted that the concentration of the second solid electrolyte in the hybrid layer can be confirmed by analyzing the composition of the hybrid layer in cross-section along the stacking direction of the battery using scanning electron microscopy (SEM), energy dispersive X-ray diffraction (EDX), and X-ray photoelectron spectroscopy (XPS). The same applies to the concentration of carbon and metallic materials in the hybrid layer.

[0056] In a preferred embodiment of the present invention, the concentration (mass %) of the second solid electrolyte in the hybrid layer decreases from the solid electrolyte layer side toward the negative electrode intermediate layer side in the stacking direction of the power generation element, and the mass ratio (second solid electrolyte: total amount of carbon material and metal material) of the second solid electrolyte as a whole to the total amount of carbon material and metal material available for lithium ion intercalation is 40:60 to 60:40. This allows for the easy assurance of a sufficient amount of solid electrolyte near the interface with the solid electrolyte layer, and a sufficient amount of carbon material (or carbon material and metal material) near the interface with the negative electrode intermediate layer. Therefore, the rate characteristics are further improved. It should be noted that when the hybrid layer is constructed by stacking multiple sub-hybrid layers with different mass ratios of the second solid electrolyte to the total amount of carbon material and metal material, the above values ​​are values ​​for the hybrid layer as a whole of the stack.

[0057] The total amount of the second solid electrolyte, carbon material, and metal material in the mixed layer is not particularly limited, but is preferably in the range of 80-100% by mass relative to 100% of the total solid components contained in the mixed layer, more preferably in the range of 90-100% by mass, even more preferably in the range of 95-100% by mass, and particularly preferably in the range of 98-100% by mass. This allows for a more significant achievement of the effects of the present invention. It should be noted that when the mixed layer is constructed by stacking multiple sub-mixed layers with different mass ratios of the total amount of the second solid electrolyte, carbon material, and metal material, the above values ​​are the values ​​for the mixed layer as a whole of the stacked body.

[0058] The thickness of the mixing layer is not particularly limited, for example, it is 1 to 200 μm, for example, more than 1 μm but less than 200 μm, preferably 2 to 100 μm, more preferably 2 to 50 μm, further preferably 3 to 50 μm, even more preferably 5 to 50 μm, even more preferably 10 to 30 μm, even more preferably 10 to 20 μm, even more preferably more than 10 μm but less than 20 μm, and particularly preferably 11 to 20 μm. When the thickness of the mixing layer is within the above range, a large number of reaction interfaces can be formed, which can further improve the rate characteristics. Furthermore, the decrease in energy density can be suppressed. It should be noted that when the mixing layer is constructed by stacking multiple sub-mixing layers with different mass ratios of the second solid electrolyte, carbon material, and metal material, the above values ​​are the values ​​of the mixing layer as a whole of the stacked body.

[0059] The ratio of the thickness of the mixing layer to the thickness of the negative electrode intermediate layer (thickness of the mixing layer / thickness of the negative electrode intermediate layer) is not particularly limited, but is preferably 1 or more, more preferably more than 1, and even more preferably 1.1 or more. This design ensures a sufficient thickness of the mixing layer, thus enabling the formation of a large number of reaction interfaces and further improving rate characteristics. Furthermore, it suppresses the decrease in energy density. The upper limit of the ratio of the thickness of the mixing layer to the thickness of the negative electrode intermediate layer is not particularly limited, but from the viewpoint of suppressing the decrease in energy density, it is, for example, 10 or less, preferably 5 or less, and more preferably 2 or less.

[0060] There are no particular limitations on the method for producing the hybrid layer. For example, methods such as wet coating of the hybrid layer constituent material or pressing the hybrid layer constituent material into powder can be used.

[0061] [Positive electrode active material layer] The positive electrode active material layer must contain positive electrode active material, and may contain solid electrolyte, binder, and conductive additive as needed.

[0062] There are no particular restrictions on the types of positive electrode active materials included in the positive electrode active material layer. Examples include layered rock salt type active materials such as LiCoO2, LiMnO2, LiNiO2, LiVO2, and Li(Ni-Mn-Co)O2; and LiMn2O4 and LiNiO2. 0.5 Mn 1.5 Spinel-type active materials such as O4; olivine-type active materials such as LiFePO4 and LiMnPO4; and Si-containing active materials such as Li2FeSiO4 and Li2MnSiO4. In addition, as oxide active materials other than those mentioned above, examples include Li4Ti5O4. 12 Among them, Li(Ni-Mn-Co)O2 and substances in which a portion of these transition metals are replaced by other elements (hereinafter also referred to as "NMC composite oxides") are preferably used as positive electrode active materials.

[0063] In addition, using sulfur-based positive electrode active materials is also a preferred embodiment. Examples of sulfur-based positive electrode active materials include particles or films of organic or inorganic sulfur compounds, as long as they are materials that can release lithium ions during charging and provide lithium ion insertion during discharging by utilizing the redox reaction of sulfur.

[0064] There is no particular limitation on the average particle size of the positive electrode active material, but from the viewpoint of high output, it is preferably 1 to 100 μm, and more preferably 1 to 20 μm.

[0065] The content of the positive electrode active material in the positive electrode active material layer is not particularly limited, but is preferably 30-99% by mass, more preferably 40-90% by mass, and even more preferably 45-80% by mass.

[0066] The positive electrode active material layer preferably further comprises a solid electrolyte. The specific form of the solid electrolyte included in the positive electrode active material layer can also be the form described in the solid electrolyte layer section. Because it has excellent lithium-ion conductivity and a low bulk modulus, it can follow the volume change of the positive electrode active material during charging and discharging; therefore, a sulfide solid electrolyte is preferred. There are no particular limitations on the content of the solid electrolyte in the positive electrode active material layer; for example, it is 1 to 70% by mass, preferably 10 to 60% by mass, and more preferably 20 to 55% by mass.

[0067] When a binder is used in the positive electrode active material layer, there are no particular limitations on the binder used, and any known binder may be used appropriately. There are also no particular restrictions on the amount of binder in the positive electrode active material layer.

[0068] There are no particular restrictions on the conductive additives used in the positive electrode active material layer. For example, carbon fibers (specifically, vapor-grown carbon fibers (VGCF), polyacrylonitrile-based carbon fibers, pitch-based carbon fibers, rayon-based carbon fibers, activated carbon fibers, etc.), carbon nanotubes (CNTs), carbon nanofibers (CNFs), and carbon black (specifically, acetylene black, Ketjen black (registered trademark), furnace black, channel black, pyrolytic carbon black, etc.) can be used. The content of the conductive additives in the positive electrode active material layer is not particularly limited, for example, it can be 1–10% by mass.

[0069] The thickness of the positive electrode active material layer varies depending on the structure of the target all-solid-state battery, typically ranging from 0.1 to 1000 μm, preferably from 10 to 300 μm, and more preferably from 40 to 150 μm.

[0070] The above describes one embodiment of the all-solid-state battery of the present invention. However, the present invention is not limited to the solution described in the above embodiment, and appropriate modifications can be made based on the claims.

[0071] For example, as a type of battery for which the all-solid-state lithium secondary battery of the present invention is applied, a bipolar battery comprising a bipolar electrode is also mentioned, wherein the bipolar electrode has a positive electrode active material layer electrically bonded to one side of the current collector and a negative electrode active material layer electrically bonded to the opposite side of the current collector.

[0072] It should be noted that the following embodiments are also included within the scope of the present invention: the all-solid-state battery of the first embodiment having the features of the second embodiment of the present invention; the all-solid-state battery of the second embodiment having the features of the third embodiment of the present invention; the all-solid-state battery of any one of the first to third embodiments having the features of the fourth embodiment of the present invention; the all-solid-state battery of any one of the first to fourth embodiments having the features of the fifth embodiment of the present invention; and the all-solid-state battery of any one of the first to fifth aspects having the features of the sixth embodiment of the present invention.

[0073] Example

[0074] The present invention will now be described in more detail through examples. However, the scope of the present invention is not limited to the following examples. It should be noted that the following operations are performed inside a glove box. In addition, the utensils and devices used inside the glove box are thoroughly dried beforehand.

[0075] <Example of battery cell manufacturing for evaluation> [Example 1] (Fabrication of the solid electrolyte layer) In a glove box with an argon atmosphere at a dew point below -68°C, a sulfide solid electrolyte (Li6PS5Cl, average particle size (D50): 0.8μm) of silver sulfide-germanium ore was fed into a powder pressing machine and pressed at 400MPa to form a solid electrolyte layer with a diameter of φ20mm. The thickness of the solid electrolyte layer was 40μm.

[0076] (Fabrication of the positive electrode active material layer) In a glove box under an argon atmosphere with a dew point below -68°C, the NMC composite oxide (LiNi) used as the positive electrode active material was weighed. 0.8 Mn 0.1 Co 0.1 O2), carbon fiber as a conductive additive, and silver sulfide-germanium sulfide solid electrolyte (Li6PS5Cl) as a solid electrolyte are mixed in a mass ratio of 60:6:34. The mixture is then fed into a powder pressing machine and pressed at 200 MPa to form a positive electrode active material layer on one side of the prepared solid electrolyte layer. The thickness of the positive electrode active material layer is 100 μm.

[0077] (Creating the hybrid layer) Silver nanoparticles (Ag, average particle size (D50): 60 nm) and carbon black (C, average particle size (D50): 35 nm) were weighed and mixed at a mass ratio of Ag:C = 1:3 to obtain an Ag / C mixed powder. Next, using a sulfide-type solid electrolyte (Li6PS5Cl) as the solid electrolyte, the Ag / C mixed powder and the solid electrolyte were mixed at a mass ratio of 25:75. The resulting mixture was fed into the powder pressing machine from the side opposite to the side where the positive electrode active material layer was disposed, and pressed at 200 MPa to form a 2.7 μm thick sub-mixed layer 1 (solid electrolyte layer side) on the side of the solid electrolyte layer opposite to the side where the positive electrode active material layer was disposed.

[0078] Then, Ag / C mixed powder and solid electrolyte are mixed at a mass ratio of 50:50, and the resulting mixture is fed into the above-mentioned powder pressing machine and pressed at 200MPa to form a sub-mixed layer 2 (middle) with a thickness of 2.7μm on the above-mentioned sub-mixed layer 1.

[0079] Next, Ag / C mixed powder and solid electrolyte are mixed at a mass ratio of 75:25. The resulting mixture is fed into the aforementioned powder pressing machine and pressed at 200 MPa to form a sub-mixed layer 3 (negative electrode intermediate layer side) with a thickness of 2.7 μm on the aforementioned sub-mixed layer 2. The overall thickness of the mixed layer consisting of sub-mixed layer 1, sub-mixed layer 2, and sub-mixed layer 3 is 8 μm.

[0080] (Fabrication of the negative electrode intermediate layer) The Ag / C mixed powder is fed into the powder pressing machine and pressed at 200 MPa to form a negative electrode intermediate layer with a thickness of 10 μm on the mixed layer 3.

[0081] (Evaluation of battery cell manufacturing) An aluminum foil serving as a positive current collector is disposed on the surface of the positive active material layer of the aforementioned laminated structure consisting of a positive active material layer, a solid electrolyte layer, a sub-mixing layer 1, a sub-mixing layer 2, a sub-mixing layer 3, and a negative intermediate layer. A stainless steel foil serving as a negative current collector is disposed on the surface of the negative intermediate layer. Next, a positive electrode lead and a negative electrode lead are connected to the positive and negative current collectors, respectively, to obtain an evaluation cell for the lithium deposition type all-solid-state lithium secondary battery of this embodiment.

[0082] [Example 2] In the above (fabrication of the hybrid layer), by adjusting the amount of material input, the thicknesses of sub-hybrid layer 1, sub-hybrid layer 2, and sub-hybrid layer 3 are each 3.3 μm. Otherwise, the evaluation cell of this embodiment is fabricated using the same method as in Example 1. The overall thickness of the hybrid layer, which combines sub-hybrid layer 1, sub-hybrid layer 2, and sub-hybrid layer 3, is 10 μm.

[0083] [Example 3] In the above (fabrication of the hybrid layer), by adjusting the amount of material input, the thicknesses of sub-hybrid layer 1, sub-hybrid layer 2, and sub-hybrid layer 3 are each 4 μm. Otherwise, the evaluation cell of this embodiment is fabricated using the same method as in Example 1. The overall thickness of the hybrid layer, which combines sub-hybrid layer 1, sub-hybrid layer 2, and sub-hybrid layer 3, is 12 μm.

[0084] [Example 4] In the above (fabrication of the mixed layer), the mixture of Ag / C mixed powder and solid electrolyte at a mass ratio of 50:50 was fed into a powder pressing machine and pressed at 200MPa. A mixed layer consisting of only one layer with a thickness of 10μm was formed on the side opposite to the side of the solid electrolyte layer where the positive electrode active material layer is disposed. Otherwise, the evaluation cell of this embodiment was made by the same method as in Example 1.

[0085] [Example 5] In the above (fabrication of the mixed layer), sub-mixed layer 1 (solid electrolyte layer side) is prepared by mixing Ag / C mixed powder and solid electrolyte at a mass ratio of 5:95, sub-mixed layer 2 (middle) is prepared by mixing Ag / C mixed powder and solid electrolyte at a mass ratio of 30:70, and sub-mixed layer 3 (negative electrode middle layer side) is prepared by mixing Ag / C mixed powder and solid electrolyte at a mass ratio of 55:45. Otherwise, the evaluation cell of this embodiment is prepared by the same method as in Example 2.

[0086] [Example 6] In the above (fabrication of the mixed layer), sub-mixed layer 1 (solid electrolyte layer side) is prepared by mixing Ag / C mixed powder and solid electrolyte in a mass ratio of 45:55, sub-mixed layer 2 (middle) is prepared by mixing Ag / C mixed powder and solid electrolyte in a mass ratio of 70:30, and mixed layer 3 (negative electrode middle layer side) is prepared by mixing Ag / C mixed powder and solid electrolyte in a mass ratio of 95:5. Otherwise, the evaluation cell of this embodiment is prepared by the same method as in Example 2.

[0087] [Comparative Example 1] In Example 2, the negative electrode intermediate layer was not fabricated, and the sub-mixing layer 3 was made to directly contact the stainless steel foil, which serves as the negative electrode current collector. Otherwise, the evaluation cell of this comparative example was fabricated using the same method as in Example 2.

[0088] [Comparative Example 2] In the above (fabrication of the hybrid layer), by adjusting the amount of material input, the thicknesses of sub-hybrid layer 1, sub-hybrid layer 2, and sub-hybrid layer 3 were each 6.7 μm. Otherwise, the evaluation cell of this comparative example was fabricated using the same method as Comparative Example 1. The overall thickness of the hybrid layer, which combines sub-hybrid layer 1, sub-hybrid layer 2, and sub-hybrid layer 3, is 20 μm.

[0089] [Comparative Example 3] In Example 1, no mixing layer was made. Instead, a negative electrode intermediate layer with a thickness of 20 μm was formed on the side of the solid electrolyte layer opposite to the side where the positive electrode active material layer was disposed. Otherwise, the evaluation cell of this comparative example was made by the same method as in Example 1.

[0090] <Charge and Discharge Test> The evaluation cells (before initial charging) fabricated above were subjected to a constraint pressure of 3 MPa in the stacking direction using a pressurizing component, and charge-discharge tests were conducted under the following conditions. Then, the rate performance was evaluated under the following conditions: (Charge and discharge test conditions) Evaluation temperature: 333K (60℃) Voltage range: 2.5~4.3V Charging process: CCCV (0.02C cutoff) Charging rate: 0.1C Discharge process: CC Discharge rate: 0.1C After charging and discharging, let stand for 30 minutes each time.

[0091] The battery cells were evaluated using a charge-discharge test chamber. In a thermostatic bath set to the aforementioned evaluation temperature, during the charging process (lithium metal deposition onto the negative electrode current collector), the chamber was set to constant current / constant voltage (CCCV) mode, charging at 0.1C to 4.3V (0.02C cutoff). Then, during the discharging process (lithium metal dissolution on the negative electrode current collector), the chamber was set to constant current (CC) mode, discharging at 0.1C to 2.5V. Here, 1C refers to the current value at which the battery reaches a fully charged (100% charged) state after charging for 1 hour.

[0092] (Rate characteristics) Evaluation temperature: 333K (60℃) Voltage range: 2.5~4.3V Charging process: CCCV (0.02C cutoff) Charging rate: 3.5C Discharge process: CC Discharge rate: 0.1C After charging and discharging, let stand for 30 minutes each time.

[0093] The battery cells were evaluated using a charge-discharge tester. In a thermostatic bath set to the aforementioned evaluation temperature, during the charging process (lithium metal deposition onto the negative electrode current collector), a constant current / constant voltage (CCCV) mode was used, charging at 3.5C to 4.3V (0.02C cutoff). Then, during the discharging process (lithium metal dissolution on the negative electrode current collector), a constant current (CC) mode was used, discharging at 0.1C to 2.5V. Here, the rate characteristic was evaluated based on the ratio of the charging capacity at 3.5C to the charging capacity at 0.1C (charging capacity at 3.5C / charging capacity at 0.1C). The results are shown in Table 1 below. It should be noted that in Table 1, the SE mass ratio is the ratio of the mass of the solid electrolyte to the total mass in each layer. Furthermore, in sub-mixed layers 1 to 3, the value calculated as SE mass ratio × 100 corresponds to the concentration (mass %) of the solid electrolyte in these sub-mixed layers.

[0094] [Table 1] Table 1

[0095] As shown in Table 1, the cells of Examples 1-6, which have the specified hybrid layer and negative electrode intermediate layer, exhibit high-speed characteristics. In contrast, short circuits occurred in the cells of Comparative Examples 1 and 2, which do not have a negative electrode intermediate layer, making it impossible to evaluate their speed characteristics. Furthermore, it is evident that the battery of Comparative Example 3, which does not have a hybrid layer, cannot achieve high-speed characteristics.

[0096] Explanation of reference numerals in the attached figures

[0097] 10a: Stacked secondary battery; 11': Negative current collector; 11”: Positive current collector; 13: Negative electrode active material layer; 14: Negative electrode intermediate layer; 15: Positive electrode active material layer; 16: Hybrid layer; 17: Solid electrolyte layer; 19: Single cell layer; 21: Power generation components; 25: Negative current collector; 27: Positive current collector; 29: Laminated film.

Claims

1. An all-solid-state battery, characterized in that, It has a power generation element, which has: A positive electrode having a positive electrode active material layer containing a positive electrode active material; The negative electrode has a negative current collector, on which lithium metal is deposited during charging; A solid electrolyte layer, which is located between the positive electrode and the negative electrode, contains a first solid electrolyte; A negative electrode intermediate layer is disposed between the solid electrolyte layer and the negative electrode. This negative electrode intermediate layer is composed of a negative electrode intermediate layer constituent material, which contains at least one material selected from the group consisting of carbon materials suitable for lithium-ion intercalation. The all-solid-state battery also has a hybrid layer, which is adjacent to the main surface of the solid electrolyte layer opposite to the negative electrode intermediate layer and the main surface of the negative electrode intermediate layer opposite to the solid electrolyte layer, respectively. The hybrid layer comprises a hybrid layer constitutive material containing at least one selected from the group consisting of a second solid electrolyte and a carbon material available for lithium-ion intercalation.

2. The all-solid-state battery according to claim 1, The concentration, i.e., mass % of the second solid electrolyte in the mixed layer is constant in the stacking direction of the power generation element, or decreases from the solid electrolyte layer side toward the negative electrode intermediate layer side in the stacking direction of the power generation element.

3. The all-solid-state battery according to claim 2, The concentration, i.e., mass % of the second solid electrolyte in the hybrid layer decreases from the solid electrolyte layer side toward the negative electrode intermediate layer side in the stacking direction of the power generation element. The thickness of the hybrid layer is set as d, and is 70% or more in the region from the interface with the solid electrolyte layer to 0.2d in the stacking direction of the power generation element, and is 30% or less in the region from the interface with the negative electrode intermediate layer to 0.2d.

4. The all-solid-state battery according to claim 1 or 2, The ratio of the thickness of the hybrid layer to the thickness of the negative electrode intermediate layer, i.e., the ratio of the thickness of the hybrid layer to the thickness of the negative electrode intermediate layer, is 1 or more.

5. The all-solid-state battery according to claim 1 or 2, The mass ratio of the second solid electrolyte to the total amount of carbon material and metal material in the mixed layer material, i.e., the total amount of second solid electrolyte: carbon material and metal material, is 40:60 to 60:

40.

6. The all-solid-state battery according to claim 1 or 2, The first solid electrolyte and / or the second solid electrolyte are sulfide solid electrolytes containing S, Li and P elements or sulfide solid electrolytes containing S, Li, Ge and P elements.

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