JP2014035812A - Sulfide solid state battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sulfide solid state battery capable of suppressing deterioration in after-endurance battery characteristics.SOLUTION: In a sulfide solid state battery, a negative electrode layer comprises a particulate metal or a metal compound and a particulate sulfide solid electrolyte material, and a ratio (D/D) between the average particle size (D) of the metal or metal compound and the average particle size (D) of the sulfide solid electrolyte material is 2 or more and less than 7.

Description

  The present invention relates to a sulfide solid-state battery, and more particularly to a sulfide solid-state battery that can suppress deterioration of battery characteristics after durability by making a negative electrode layer into a specific configuration.

In recent years, lithium batteries have been put into practical use as batteries having high voltage and high energy density. Due to the expansion of the use of lithium batteries in a wide range of fields and the demand for high performance, various studies have been conducted to further improve the performance of lithium batteries.
Among them, since the electrolyte is not used compared to the conventional non-aqueous electrolyte lithium battery, the system required for improving the safety when using the non-aqueous electrolyte can be simplified. Therefore, the practical use of a solid battery is expected.

However, in order to realize the practical application of solid state batteries, various improvements such as the creation of a solid electrolyte capable of providing high capacity and high output and / or the creation of electrodes capable of realizing high electrode utilization efficiency are required. is there.
A sulfide solid electrolyte material such as Li ₂ S—P ₂ S ₅ has been proposed as one of the technologies capable of realizing the high capacity and high output of this solid battery.
However, it is known that a sulfide solid battery using a sulfide solid electrolyte material such as Li ₂ S—P ₂ S ₅ described above deteriorates battery characteristics after durability. One possible cause of the deterioration in battery characteristics after endurance is that the active material and the sulfide solid electrolyte material are directly connected to each other at the interface between the active material constituting at least a part of the electrode and the sulfide solid electrolyte material. It is considered that the reaction occurs by contact and an insulating layer is formed, the charge conductivity of lithium ions is lowered, and the reaction resistance of the sulfide solid state battery is increased.

Various studies have been made to suppress reaction resistance in a sulfide solid state battery using the sulfide solid electrolyte material.
For example, in a sulfide solid state battery, in order to prevent a reaction from occurring at the interface between the positive electrode active material and the sulfide solid electrolyte material layer and forming a high resistance reaction layer at the interface, Attempts have been made to form a reaction suppression layer on the surface of the sulfide solid electrolyte material. For example, in order to form a reaction suppression layer, attempts have been made to use lithium niobate, lithium titanate, lithium phosphate, etc., but although the initial reaction suppression is effective, it is inferior in durability. there were.

  Furthermore, Patent Document 1 describes a lithium battery including a positive electrode mixture obtained by mechanically milling a positive electrode active material and a sulfide-based solid electrolyte, an electrolyte layer composed of a sulfide-based solid electrolyte, and a negative electrode. As a specific example, the positive electrode active material is a mixture of two positive electrode active material powders having different average particle diameters, the particle size ratio of which is 0.08 to 1, and the negative electrode is graphite and a sulfide-based solid electrolyte. A lithium battery, which is a negative electrode mixture obtained by mixing the above, is shown.

  Patent Document 2 discloses a mixed substance having two electrode layers, a positive electrode and a negative electrode, sandwiching a solid electrolyte, and at least one electrode layer including at least one kind of electrode active material particles and solid electrolyte particles. An all-solid battery comprising a sintered body and having a coating layer with a thickness of 1 to 200 nm in at least 30 area% of a grain boundary surrounding the electrode active material particles is described. As a specific example, a non-sulfide solid electrolyte is described. An example in which an all-solid battery is obtained by firing an electrode layer precursor containing benzene is shown, and the average particle size of the electrode active material powder is preferably 0.1 to 10 μm in order to increase the electrode reaction area, 3 μm is more preferable, 0.1 to 1 μm is most preferable, and the average particle size of the solid electrolyte powder included in the electrode layer precursor is preferably 0.1 to 10 μm, more preferably 0.1 to 1 μm, in order to increase the reaction area, 0.1-0. 6 μm is shown to be most preferred.

JP 2010-67499 A JP 2011-86610 A

However, even when these known techniques are applied, the obtained sulfide solid state battery has a large deterioration in battery characteristics after durability.
Accordingly, an object of the present invention is to provide a sulfide solid state battery capable of suppressing deterioration of battery characteristics after durability.

The present invention is a sulfide solid state battery, wherein the negative electrode layer is composed of a particulate metal or metal compound and a particulate sulfide solid electrolyte material, and the average particle diameter (D _M ) of the metal or metal compound and the above the average particle size of the sulfide solid electrolyte material _{(D SE)} the ratio of _(D M _/ D _SE) is less than 2 to 7, regarding the solid-state battery.
In addition, each average particle diameter (D _M , D _SE ) of the metal or the metal compound and the sulfide solid electrolyte material is an average particle diameter D50 obtained by a measurement method described in detail in the column of Examples described later.

  ADVANTAGE OF THE INVENTION According to this invention, the sulfide solid state battery which can prevent thru | or suppress the fall of the battery characteristic after durability can be obtained.

FIG. 1 shows the average particle size (D _M ) of particulate metal and the average particle size of particulate sulfide solid electrolyte material in the sulfide solid state battery of the embodiment of the present invention and the sulfide solid state battery outside the scope of the present invention. It is a graph which compares and shows the relationship between the ratio (D _M / D _SE ) with the diameter (D _SE ) and the discharge capacity retention rate after 100 cycles of the sulfide solid state battery.

In particular, in the present invention, the following embodiments can be mentioned.
1) The sulfide solid state battery wherein the negative electrode layer further contains a carbon material.
2) The sulfide solid state battery in which the negative electrode layer includes a particulate carbon material, a particulate metal, and a particulate sulfide solid electrolyte material.
3) The sulfide solid state battery wherein the metal is Al.
4) The said sulfide solid battery whose ratio of the said sulfide solid electrolyte material in the said negative electrode layer is 25-75 mass%.
5) The sulfide solid state battery wherein the sulfide electrolyte material contains Li ₂ S and P ₂ S ₅ .
6) The sulfide solid state battery wherein an average particle diameter (D _M ) of the particulate metal or metal compound is 2 to 10 μm.
7) The sulfide solid state battery wherein an average particle diameter (D _SE ) of the sulfide solid electrolyte material is 0.5 to 5 μm.
8) wherein the sulfide-based solid battery average particle size of the carbon material _{(D SE)} is 5 to 20 [mu] m.
9) The said sulfide solid battery whose ratio of the said carbon material and a metal or a metal compound is 20: 1-5: 1 (mass ratio).

A sulfide solid state battery according to an embodiment of the present invention is a sulfide solid state battery in which a positive electrode layer, a sulfide solid electrolyte material layer, and a negative electrode layer are laminated, and the negative electrode layer includes a carbon material and particulate metal or It consists of a negative electrode mixture of a negative electrode active material composed of a metal compound and a particulate sulfide solid electrolyte material, and an average particle diameter (D _M ) of the metal or metal compound and an average particle diameter of the sulfide solid electrolyte material ( D _SE) ratio of _(D M _/ D _SE) is required to be a sulfide solid battery is less than 2 or 7, whereby the deterioration of the reaction resistance in the expansion and contraction and solid state battery of the negative electrode active material It can suppress and the battery characteristic fall after durability of a sulfide solid state battery can be suppressed.

According to the sulfide solid state battery of the embodiment of the present invention, as shown in FIG. 1, the average particle diameter (D _M ) of the particulate metal or metal compound and the average particle diameter of the particulate sulfide solid electrolyte material ( D _SE) ratio between the substantially equal average particle sizes (D _M) and particulate sulfide solid electrolyte material when and particulate metal or metal compound _{(D SE) (D M /} D SE ) Is higher than 7, the discharge capacity retention rate after 100 cycles showing the durability characteristics of the sulfide solid state battery is high.

  The sulfide solid state battery according to the embodiment of the present invention has not been sufficiently theoretically elucidated as the discharge capacity retention rate after 100 cycles is higher than that of the sulfide solid state battery outside the scope of the present invention. Can be considered. That is, the active material of particulate metal or metal compound has a large volume expansion associated with charging / discharging, and therefore, the periphery of the metal active material is likely to be cracked due to the volume expansion. Further, when the metal or metal compound itself is excessively large, the absolute value of volume expansion (absolute value of the amount of change of one particle) accompanying charging / discharging is large, which may lead to destruction of the electrode layer. Furthermore, when the particles of the sulfide solid electrolyte material become too small, there are many interfaces between the particles of the sulfide solid electrolyte material, and the resistance can be increased. On the other hand, in the sulfide solid state battery according to the embodiment of the present invention, cracks due to volume expansion around these metal active materials, destruction of the electrode layer, and the particle interface of the sulfide solid electrolyte material It is considered that the increase in resistance is prevented or suppressed, and further, the contact failure between the sulfide solid electrolyte material and the negative electrode active material is suppressed by relaxation of expansion and contraction due to mixing with the carbon material.

In the sulfide solid state battery of the embodiment of the present invention, the negative electrode layer is composed of a negative electrode mixture of a carbon material and a negative active material of a particulate metal or metal compound and a particulate sulfide solid electrolyte material, When the ratio of the average particle diameter (D _M ) of the particulate metal or metal compound and the average particle diameter (D _SE ) of the sulfide solid electrolyte material is within the above range, the particulate metal or metal The battery energy density can be improved by the compound.

In the embodiment of the present invention, a particulate metal or metal compound is used as the negative electrode active material.
Examples of the particulate metal or metal compound include a particulate metal or alloy such as Al, Sn, Si, In, Cu ₆ Sn ₅ or the like, or a particulate metal compound such as an oxide, sulfide, or the like of the metal. Phosphorus compounds or alloys with other metals, oxides of alloys, sulfides or phosphorus compounds, such as SiO, SnO, SnS, SnP, Ti ₂ SnO _{6 and the} like, preferably metals such as Al. The particulate metal or metal compound may preferably have an average particle size (D _M ) of 2 to 10 μm.

By including the particulate metal or metal compound, the volume capacity of the negative electrode layer, that is, the battery energy density (energy that can be taken out per unit volume of the battery, that is, the amount of electricity) can be improved. By controlling the ratio (D _M / D _SE ) to the average particle diameter (D _SE ) of the material in the range of 2 or more and less than 7, the cycle characteristics of the battery can be improved.
In the embodiment of the present invention, the ratio of the carbon material to the metal or metal compound is preferably 20: 1 to 5: 1 (mass ratio).

The sulfide solid electrolyte material in the present invention is not particularly limited as long as it is a particulate sulfide solid electrolyte. For example, a material containing Li ₂ S and SiS ₂ , for example, Li ₂ S—SiS ₂ , LiI—Li _{2. S-SiS 2, liI-li} 2 S-P 2 S 5, LiI-Li 2 S-B 2 S 3, Li 3 PO 4 -Li 2 S-Si 2 S, Li 3 PO 4 -Li 2 S-SiS ₂ , sulfides such as LiPO ₄ —Li ₂ S—SiS, LiI—Li ₂ S—P ₂ O ₅ , LiI—Li ₃ PO ₄ —P ₂ S ₅ , Li ₃ PS ₄ , Li ₂ S—P ₂ S ₅ A physical amorphous solid electrolyte, preferably Li ₂ S—P ₂ S ₅ is used.

The Li ₂ S—P ₂ S ₅ can be obtained from lithium sulfide and diphosphorus pentasulfide and / or simple phosphorus and simple sulfur. For example, these raw materials are melt-reacted and then rapidly cooled or the raw materials are used. It can be obtained by heat-treating sulfide glass obtained by processing by a mechanical milling method. The mixing molar ratio of lithium sulfide to diphosphorus pentasulfide or simple phosphorus and simple sulfur is usually 50:50 to 80:20, preferably 60:40 to 75:25, and preferably Li ₂ S: P _2. S ₅ = 70: 30~75: is about 25 (mole ratio).
In the sulfide solid state battery of the present invention, the sulfide solid electrolyte material preferably has an average particle radius (D _SE ) of 0.5 to 5 μm, particularly 0.5 to 3 μm. The average particle diameter (D _SE ) of the sulfide solid electrolyte material can be adjusted by changing the mechanical milling conditions (milling time, ball diameter) by the planetary ball mill at the time of manufacture.

The carbon material used in the negative electrode mixture of the embodiment of the present invention is not particularly limited, but particulate carbon materials such as graphite, such as natural graphite, artificial graphite, or carbon, such as soft carbon, hard carbon, etc. Can be mentioned. The average particle diameter (D _CB ) of the carbon material is preferably 5 to 20 μm.

The negative electrode mixture constituting the negative electrode layer in the sulfide solid state battery of the embodiment of the present invention is obtained by mixing the carbon material, the particulate metal or metal compound, and the particulate sulfide solid electrolyte material. Can do. The mixing is preferably performed by a method in which the particle diameters of the carbon material, the particulate metal or metal compound, and the particulate sulfide solid electrolyte material, and thus the particle diameter ratio, do not change substantially.
As the above-mentioned method, for example, particles of both components are superposed using an ultrasonic homogenizer in the presence of a hydrocarbon solvent, for example, a chain alkane such as hexane, heptane, and octane or a cyclic alkane such as cyclohexane, cycloheptane, and cyclooctane. A method of obtaining a mixed powder by sonicating and then drying and evaporating the hydrocarbon solvent may be mentioned.
In the embodiment of the present invention, the ratio of the sulfide solid electrolyte material in the negative electrode layer (in the negative electrode mixture) is preferably 25 to 75% by mass.

In the sulfide solid state battery of the embodiment of the present invention, the negative electrode mixture constituting the negative electrode layer, the positive electrode layer which is another constituent material, and the sulfide solid electrolyte material layer are arranged on one side of the sulfide solid electrolyte material layer. The positive electrode layer can be obtained by laminating the negative electrode layer on the other side.
Examples of the sulfide solid electrolyte material in the sulfide solid electrolyte material layer include those shown in the negative electrode layer or other sulfide solid electrolyte materials, preferably the same sulfide solid electrolyte material.

The positive electrode layer can be formed of, for example, a positive electrode mixture containing a positive electrode active material and a sulfide solid electrolyte material.
The positive electrode active material is not particularly limited as long as it is an active material that can be used for a Li-ion battery. For example, lithium cobaltate (Li _x CoO ₂ ), lithium nickelate (Li _x NiO ₂ ), nickel manganese lithium cobaltate (Li _{1 + x} Ni _1/3 Mn _1/3 Co _1/3 O ₂ ), nickel nickel cobaltate (LiCo _0.3 Ni _0.7 O ₂ ), lithium manganate (Li _x Mn ₂ O ₄ ), titanic acid Lithium (Li _4/3 Ti _5/3 O ₄ ), lithium manganate compound (Li _{1 + x} M _y Mn _2−xy O ₄ ; M = Al, Mg, Fe, Cr, Co, Ni, Zn), titanium lithium acid _(Li x _TiO y), phosphate metal lithium _{(LiMPO 4, M = Fe,} Mn, Co, Ni), vanadium oxide _{(V 2 O} 5), Molybdenum (MoO3), titanium sulfide _(TiS 2), lithium cobalt nitride (LiCoN), lithium silicon nitride (LiCoN), lithium metal, lithium alloy (LiM, M = Sn, Si , Al, Ge, Sb, P ), Lithium-storable intermetallic compounds (MgxM, M = Sn, Ge, Sb, or XySb, X = In, Cu, Mn) and derivatives thereof.
In particular, Li _x CoO ₂ , Li _x NiO ₂ , Li _x Mn ₂ O ₄ , Li _x Ni _1/2 Mn _1/2 O ₂ , Li _x Ni _1/3 Co _1/3 Mn _1/3 O ₂ , Li _x [Ni _y Li _{1 / 3-2y / 3} ] O ₃ (0 ≦ x ≦ 1, 0 <y <1/2) and lithium or transition metal of these lithium transition metal oxides were substituted with other elements Examples include lithium transition metal compounds, particularly layered layers such as LiCoO ₂ and LiNiO ₂ , olivine or spinel.

The positive electrode mixture constituting the positive electrode layer may include the positive electrode active material and the sulfide solid electrolyte material, and may further include other components such as a conductive additive.
As the conductive aid, carbon materials such as VGCF (Vapor Grown Carbon Fiber), carbon black, carbon nanotube, and carbon nanofiber, and metal materials can be used.
The proportion of each constituent material in the positive electrode mixture constituting the positive electrode layer is preferably 30 to 80% by mass, particularly 50 to 80% by mass of the positive electrode active material in 100% by mass of the positive electrode mixture, and sulfide. The solid electrolyte material may be 10 to 50% by mass, particularly 15 to 50% by mass, and the conductive additive may be 10% by mass or less, and particularly 1 to 10% by mass.

The sulfide solid state battery of the present invention is, for example, placed in a cell containing a sulfide solid electrolyte material in a mold and pressed to form a sulfide solid electrolyte material layer, and a positive electrode mixture is placed on one side and pressed. It can be manufactured by forming a positive electrode layer, then putting a negative electrode mixture on the opposite side, pressing to form a negative electrode layer, and attaching a current collector to each of the positive electrode layer and the negative electrode layer.
A metal foil, such as an Al foil, can be used as the current collector for the positive electrode layer, and a metal foil, such as a Cu foil, can be used as the current collector for the negative electrode layer.

Examples of the present invention will be described below.
The following examples are for illustrative purposes only and do not limit the invention.
Note that the measurement methods shown below are merely examples, and measurement methods considered equivalent to those skilled in the art can be used as well.
In each of the following examples, the average particle size of each material is determined by measuring the particle size distribution by the laser diffraction scattering method according to the following method, and the average particle size (cumulative from the fine particle side in the obtained particle size distribution is 50% by mass ( D _M , D _SE ) were determined.

Example 1
1) Synthesis of sulfide solid electrolyte material 0.7656 g of Li ₂ S (manufactured by Nippon Chemical Industry Co., Ltd.) and 1.2344 g of P ₂ S ₅ (Aldrich) are weighed and mixed for 5 minutes in an agate mortar, and then heptane 4 g was added, and mechanical milling was performed for 40 hours using a planetary ball mill. Subsequently, a sulfide solid electrolyte material having an average particle diameter of 1.5 μm was obtained by mechanical milling at 150 rpm in a heptane and butyl ether solvent using a ZrO ₂ ball having a ball diameter of 1 mm.

2) Preparation of sulfide solid-state battery LiNi _1/3 Co _1/3 Mn _1/3 O ₂ (Nichia Corporation) as positive electrode active material 12.03 mg and VGCF (Showa Denko) 0.51 mg Then, 5.03 mg of the above-mentioned sulfide solid electrolyte material was weighed, put into a heptane solvent, ultrasonically dispersed with an ultrasonic homogenizer, and then dried to obtain a positive electrode mixture.
A sulfide solid electrolyte material having an average particle diameter of 1.5 μm obtained from graphite (Mitsubishi Chemical Corporation) having an average particle diameter of 10 μm and 0.68 mg of aluminum having an average particle diameter of 3 μm (High Purity Research Institute Co., Ltd.) and 1) above. 8.24 mg was weighed, put into a heptane solvent, subjected to ultrasonic dispersion with an ultrasonic homogenizer, and then dried to obtain a negative electrode mixture [D _M / D _SE = 2.0].
The sulfide solid electrolyte material into a mold of 1 cm ² to 18mg weighed and pressed to form a sulfide solid electrolyte material layer with 1 ton / cm ^2, placed the positive electrode mixture 17.57mg one side thereof, The positive electrode layer was formed by pressing at 1 ton / cm ² . On the opposite side, 16.16 mg of the negative electrode mixture was put and pressed at 4 ton / cm ² to form a negative electrode layer. Further, as a current collector, a sulfide solid battery was produced using a 15 μm Al foil (Nihon Foil Co., Ltd.) on the positive electrode side and a 10 μm Cu foil (Nihon Foil Co., Ltd.) on the negative electrode side.

3) Battery evaluation The obtained sulfide solid state battery was evaluated under the following conditions.
1) After charging cccv (constant current constant voltage) to 4.2 V at 0.3 mA, the initial capacity was confirmed by discharging at 3 V and 0.3 mA.
2) After cc charging to 4.2 V at 3 mA at 60 ° C., discharging was performed 100 cycles at 3 V and 0.3 mA.
3) After cccv charging to 4.2 V at 3 mA, discharging was performed at 3 V and 0.3 mA to confirm the capacity after endurance.
The ratio (%) of the obtained discharge capacity after 100 cycles to the initial capacity is taken as the discharge capacity retention rate after 100 cycles, and is shown together with other results in FIG.

Example 2
In place of the sulfide solid electrolyte material having an average particle diameter of 1.5 μm, the conditions for the synthesis of the sulfide solid electrolyte material were changed (the ball diameter was changed to 0.3 mm). A negative electrode composed of particulate graphite, particulate aluminum, and particulate sulfide solid electrolyte material in the same manner as in Example 1 except that a sulfide solid electrolyte material of 0.8 μm was synthesized and this sulfide solid electrolyte material was used. A mixture [D _M / D _SE = 3.75] was produced, and a sulfide solid state battery was produced in the same manner as in Example 1 except that this negative electrode mixture was used.
About the obtained battery, it carried out similarly to Example 1, and obtained the discharge capacity maintenance factor after 100 cycles. FIG. 1 shows the results together with other results.

Example 3
Instead of aluminum having an average particle diameter of 3 μm (High Purity Research Institute Co., Ltd.), it was replaced by aluminum having an average particle diameter of 10 μm (High Purity Research Institute Co., Ltd.) and a sulfide solid electrolyte material having an average particle diameter of 1.5 μm. Other than using the sulfide solid electrolyte material having an average particle diameter of 2.5 μm synthesized in the same manner as in Example 1 except that the conditions for the synthesis of the solid electrolyte material were changed (the mechanical milling time was changed to 5 hours). In the same manner as in Example 1, a negative electrode mixture [D _M / D _SE = 4.0] composed of particulate graphite, particulate aluminum, and a particulate sulfide solid electrolyte material was prepared, and this negative electrode mixture was used. Produced a sulfide solid state battery in the same manner as in Example 1.
About the obtained battery, it carried out similarly to Example 1, and obtained the discharge capacity maintenance factor after 100 cycles. FIG. 1 shows the results together with other results.

Example 4
Particulate graphite and particulate aluminum were used in the same manner as in Example 1 except that aluminum having an average particle size of 3 μm (high purity research institute) was used instead of aluminum having an average particle size of 10 μm (high purity research institute). A negative electrode mixture [D _M / D _SE = 6.7] composed of a particulate sulfide solid electrolyte material and a negative electrode mixture was used in the same manner as in Example 1 except that this negative electrode mixture was used. Produced.
About the obtained battery, it carried out similarly to Example 1, and obtained the discharge capacity maintenance factor after 100 cycles. FIG. 1 shows the results together with other results.

Comparative Example 1
A negative electrode mixture [D _M / D _SE = 1] in the same manner as in Example 1 except that a sulfide solid electrolyte material having an average particle diameter of 2.5 μm was used instead of the sulfide solid electrolyte material having an average particle diameter of 1.5 μm. .2], a sulfide solid state battery was produced.
About the obtained battery, it carried out similarly to Example 1, and obtained the discharge capacity maintenance factor after 100 cycles. FIG. 1 shows the results together with other results.

Comparative Example 2
Instead of aluminum having an average particle size of 3 μm (High Purity Research Institute Co., Ltd.), using aluminum having an average particle size of 20 μm (High Purity Research Institute Co., Ltd.) and replacing the sulfide solid electrolyte material having an average particle size of 1.5 μm with an average A negative electrode mixture [D _M / D _SE = 8.0] and a sulfide solid state battery were produced in the same manner as in Example 1 except that a sulfide solid electrolyte material having a particle size of 2.5 μm was used.
About the obtained battery, it carried out similarly to Example 1, and obtained the discharge capacity maintenance factor after 100 cycles. FIG. 1 shows the results together with other results.

Comparative Example 3
A negative electrode mixture [D _M /] in the same manner as in Example 1 except that aluminum having an average particle diameter of 3 μm (high purity research institute) was used instead of aluminum having an average particle diameter of 20 μm (high purity research institute). D _SE = 13.3], a sulfide solid state battery was fabricated.
About the obtained battery, it carried out similarly to Example 1, and obtained the discharge capacity maintenance factor after 100 cycles. FIG. 1 shows the results together with other results.

From FIG. 1, the sulfide solid state battery in which the ratio (D _M / D _SE ) between the particulate aluminum average particle size and the average particle size of the particulate sulfide solid electrolyte material is in the range of 2 to less than 7, The ratio (D _M / D _SE ) of the average particle diameter of the aluminum particles and the average particle diameter of the particulate sulfide solid electrolyte material is 100 cycles compared to a sulfide solid battery containing a negative electrode mixture outside the above range. It is understood that the post-discharge capacity retention rate is high.

  According to the present invention, it is possible to obtain a sulfide solid state battery capable of suppressing deterioration of battery characteristics after endurance.

Claims (10)

A sulfide solid-state battery, wherein the negative electrode layer is made of a particulate metal or metal compound and a particulate sulfide solid electrolyte material, and the average particle diameter (D _M ) of the metal or metal compound and the sulfide solid electrolyte The solid battery, wherein the ratio (D _M / D _SE ) to the average particle diameter (D _SE ) of the material is 2 or more and less than 7.   The sulfide solid state battery according to claim 1, wherein the negative electrode layer further contains a carbon material.   The sulfide solid state battery according to claim 2, wherein the negative electrode layer includes a particulate carbon material, a particulate metal, and a particulate sulfide solid electrolyte material.   The sulfide solid state battery according to claim 3, wherein the metal is Al.   The sulfide solid state battery according to any one of claims 1 to 4, wherein a ratio of the sulfide solid electrolyte material in the negative electrode layer is 25 to 75 mass%. The sulfide electrolyte material, sulfide-solid-state cell according to any one of claims 1 to 5 containing Li ₂ S and _P 2 _{S 5.} The sulfide solid state battery according to any one of claims 1 to 6, wherein an average particle diameter (D _M ) of the particulate metal or metal compound is 2 to 10 µm. Sulfide-solid-state cell according to any one of claims 1 to 7 mean particle size of the sulfide solid electrolyte material _{(D SE)} is 0.5 to 5 [mu] m. 9. The sulfide solid state battery according to claim 3, wherein the carbon material has an average particle diameter (D _SE ) of 5 to 20 μm.   The sulfide solid state battery according to claim 2, wherein a ratio of the carbon material to the metal or metal compound is 20: 1 to 5: 1 (mass ratio).

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