JP6067511B2 - Sulfide solid electrolyte material, positive electrode body and lithium solid state battery - Google Patents

Description

  The present invention relates to a sulfide solid electrolyte material that achieves both suppression of increase in interface resistance and suppression of increase in bulk resistance.

  With the rapid spread of information-related equipment and communication equipment such as personal computers, video cameras, and mobile phones in recent years, development of batteries that are used as power sources has been regarded as important. Also in the automobile industry and the like, development of high-power and high-capacity batteries for electric vehicles or hybrid vehicles is being promoted. Currently, lithium batteries are attracting attention among various batteries from the viewpoint of high energy density.

  Since lithium batteries currently on the market use an electrolyte containing a flammable organic solvent, it is possible to install safety devices that suppress the temperature rise during short circuits and to improve the structure and materials to prevent short circuits. Necessary. In contrast, a lithium battery in which the electrolyte is changed to a solid electrolyte layer to make the battery completely solid does not use a flammable organic solvent in the battery, so the safety device can be simplified, and manufacturing costs and productivity can be reduced. It is considered excellent. Furthermore, a sulfide solid electrolyte material is known as a solid electrolyte material used for such a solid electrolyte layer.

Since the sulfide solid electrolyte material has high Li ion conductivity, it is useful for increasing the output of the battery, and various studies have been made heretofore. For example, in Patent Document 1, and Li 2 _{S-P 2} S ₅ based lithium ion conductor crystal glass, battery using the same as a solid electrolyte is disclosed. Non-Patent Document 1 discloses a sulfide solid electrolyte material having a ratio of Li ₂ S / P ₂ S ₅ = 2 and containing LiI. Further, in Non-Patent Document _{2, LiI-Li 2 S-} P 2 S 5 based amorphous material obtained by mechanical milling method is disclosed. Patent Document 2 discloses a nonaqueous electrolyte battery in which a combination of solid electrolytes is selected as a specific combination in order to suppress a reaction between a positive electrode active material and a solid electrolyte.

JP 2005-228570 A JP 2003-217663 A

Rene Mercier et al., “SUPERIONIC CONDUCTION IN Li2S-P2S5-LiI -GLASSES”, Solid State Ionics 5 (1981), 663-666 Naoko Torui and two others, “Synthesis of LiI-Li2S-P2S5 Amorphous Material by Mechanical Milling Method and Its Lithium Ion Conduction Properties”, Abstracts of Solid State Ionics Conference, Vol. 23, p. Issued 26-27, 2003

  The sulfide solid electrolyte material has a problem that it reacts with an electrode active material (especially a positive electrode active material), a high resistance layer is formed at the interface between the two, and the interface resistance increases. On the other hand, the present inventors have obtained the knowledge that an increase in interfacial resistance can be suppressed by including fluorine in the sulfide solid electrolyte material. However, although the sulfide solid electrolyte material containing fluorine can suppress an increase in interfacial resistance, there is a problem that the bulk resistance increases (the ionic conductivity decreases). The present invention has been made in view of the above problems, and a main object of the present invention is to provide a sulfide solid electrolyte material that achieves both suppression of increase in interface resistance and suppression of increase in bulk resistance.

  In order to solve the above problems, the present invention provides a sulfide solid electrolyte material characterized by containing at least one of Cl and Br.

  According to the present invention, since it contains at least one of Cl and Br, it is possible to obtain a sulfide solid electrolyte material that achieves both suppression of increase in interface resistance and suppression of increase in bulk resistance.

  In the above invention, it is preferable that at least one of Cl and Br is dispersed. This is because it is easy to produce a sulfide solid electrolyte material.

  In the said invention, it is preferable to have a core part which has ion conductivity, and the coating | coated part which coat | covers the surface of the said core part, and the said coating | coated part contains at least one of the said Cl and Br. This is because an increase in interface resistance can be effectively suppressed.

  In the present invention, a sulfide solid electrolyte material having a core part having ion conductivity and a coating part covering the surface of the core part, wherein the coating part contains I I will provide a.

  According to the present invention, since the covering portion contains I, it is possible to provide a sulfide solid electrolyte material that achieves both suppression of increase in interface resistance and suppression of increase in bulk resistance.

  In the said invention, it is preferable to contain Li, X (X is P, Si, Ge, Al, or B) and S. It is because it can be set as the sulfide solid electrolyte material with high Li ion conductivity.

In the above-mentioned invention, the sulfide-based solid electrolyte material preferably contains a PS ₄ ^3- structure mainly. It is because it can be set as the sulfide solid electrolyte material with little hydrogen sulfide generation amount.

  Further, in the present invention, a positive electrode body containing a positive electrode active material and a sulfide solid electrolyte material that reacts with the positive electrode active material to form a high resistance layer, wherein the sulfide solid electrolyte material is Cl, A positive electrode body comprising at least one of Br and I is provided.

  According to the present invention, since the sulfide solid electrolyte material contains at least one of Cl, Br, and I, a positive electrode body that achieves both suppression of increase in interface resistance and suppression of increase in bulk resistance, can do.

  In the said invention, it is preferable that the said positive electrode active material is an oxide positive electrode active material. This is because it easily reacts with the sulfide solid electrolyte material to form a high resistance layer. The oxide positive electrode active material also has an advantage of high energy density.

  In the said invention, it is preferable that the said oxide positive electrode active material is a rock salt layered type active material.

  In the said invention, it is preferable that the oxide coating layer is formed in the surface of the said positive electrode active material. It is because it can further suppress that a positive electrode active material and a sulfide solid electrolyte material react, and a high resistance layer is formed.

  In the said invention, it is preferable that the said sulfide solid electrolyte material contains Li, X (X is P, Si, Ge, Al, or B), and S. It is because it can be set as the sulfide solid electrolyte material with high Li ion conductivity.

In the above-mentioned invention, the sulfide-based solid electrolyte material preferably contains a PS ₄ ^3- structure mainly. It is because it can be set as the sulfide solid electrolyte material with little hydrogen sulfide generation amount.

  The present invention also provides a lithium solid state battery having a positive electrode active material layer, a negative electrode active material layer, and a solid electrolyte layer formed between the positive electrode active material layer and the negative electrode active material layer, A positive electrode active material layer is the above-described positive electrode body.

  According to the present invention, by using the positive electrode body described above as the positive electrode active material layer, it is possible to provide a lithium solid state battery that achieves both suppression of increase in interface resistance and suppression of increase in bulk resistance.

  In this invention, there exists an effect that the sulfide solid electrolyte material which made compatible suppression of the increase in interface resistance and suppression of the increase in bulk resistance can be obtained.

It is a schematic sectional drawing explaining the interface of a sulfide solid electrolyte material and an electrode active material. It is a schematic diagram explaining the effect of this invention. It is a schematic sectional drawing which shows the sulfide solid electrolyte material of this invention. It is a schematic diagram which shows an example of the positive electrode body of this invention. It is a schematic sectional drawing explaining the positive electrode body of this invention. It is a schematic sectional drawing which shows an example of the lithium solid battery of this invention. It is the result of the impedance measurement with respect to the lithium solid battery obtained in Examples 1-4 and Comparative Examples 1-3. It is a result of evaluation of charging / discharging cycle characteristics with respect to the lithium solid state battery obtained in Example 5 and Comparative Example 1. It is a result of Li ion conductivity measurement with respect to the sulfide solid electrolyte material synthesize | combined in Comparative Examples 1-3.

  Hereinafter, the sulfide solid electrolyte material, the positive electrode body and the lithium solid battery of the present invention will be described in detail.

A. First, the sulfide solid electrolyte material of the present invention will be described. The sulfide solid electrolyte material of the present invention can be roughly divided into two embodiments. Hereinafter, the sulfide solid electrolyte material of the present invention will be described separately for the first embodiment and the second embodiment.

1. First Embodiment The sulfide solid electrolyte material of the first embodiment is characterized by containing at least one of Cl and Br.

According to the first embodiment, since it contains at least one of Cl and Br, it is possible to obtain a sulfide solid electrolyte material that achieves both suppression of increase in interface resistance and suppression of increase in bulk resistance. Here, as shown in FIG. 1A, conventionally, at the interface between the sulfide solid electrolyte material 1 and the electrode active material 2, the high resistance layer X is formed by the reaction of both, and the interface resistance is reduced. There was a problem that the increase became large. As one means for solving this problem, it is known to provide a coating layer such as LiNbO _{3 on} the surface of the electrode active material 2. However, even when a coat layer is provided on the surface of the electrode active material, it is difficult to completely cover the surface of the electrode active material with the desired thickness with the coat layer, and the electrode active material and the coat It was difficult to prevent the formation of the high resistance layer because the adhesion to the layer was weak and the coat layer was easily peeled off due to shear stress or the like.

  On the other hand, as shown in FIG. 1 (b), the present inventors suppress increase in interfacial resistance due to formation of a high resistance layer by introducing fluorine (F) into the sulfide solid electrolyte material 1. I confirmed that I can do it. The reason why the increase in the interfacial resistance can be suppressed is that the fluorine contained in the sulfide solid electrolyte material 1 reacts with the metal contained in the electrode active material 2 to react at the interface between the sulfide solid electrolyte material 1 and the electrode active material 2. This is probably because a stable fluoride Y is formed. However, although the sulfide solid electrolyte material containing fluorine can suppress an increase in interfacial resistance, there is a problem that the bulk resistance increases (the ionic conductivity decreases).

The reason why the bulk resistance is increased is probably that sulfur (S) of the structural unit (unit) responsible for ionic conduction is replaced with fluorine (F) by introducing fluorine having high electronegativity and high reactivity. This is probably because ionic conduction is inhibited. For example, as shown in FIG. 2A, a sulfide solid electrolyte material (Li ₃ PS ₄ ) having a composition of 75Li ₂ S · 25P ₂ S ₅ has a PS ₄ ³⁻ structure, and this PS ₄ ^{3 -} structure greatly contributes to Li ion conductivity. When fluorine is introduced into such a sulfide solid electrolyte material, as shown in FIG. 2 (b), the sulfur (S) of PS ₄ ^3- structure is replaced with fluorine (F), and Li ion conduction is inhibited. It is thought. On the other hand, in the first embodiment, as shown in FIG. 2 (c), by introducing chlorine or bromine which is the same halogen as fluorine and is less reactive than fluorine, No replacement occurs. As a result, it is possible to obtain a sulfide solid electrolyte material that achieves both suppression of increase in interface resistance and suppression of increase in bulk resistance.

(1) Sulfide solid electrolyte material The sulfide solid electrolyte material of the first embodiment usually reacts with an electrode active material to form a high resistance layer. Formation of the high resistance layer can be confirmed by a transmission electron microscope (TEM) and energy dispersive X-ray spectroscopy (EDX). The sulfide solid electrolyte material has ionic conductivity. Although it does not specifically limit as a metal ion to conduct, For example, Li ion, Na ion, K ion, Mg ion, Ca ion etc. can be mentioned, Especially, Li ion is preferable. It is because it can be set as the sulfide solid electrolyte material useful for a lithium solid battery.

  The composition of the sulfide solid electrolyte material of the first embodiment is not particularly limited as long as it is a composition containing at least one of Cl and Br. Among them, the sulfide solid electrolyte material of the first embodiment contains Li, X (X is P, Si, Ge, Al, or B), and S in addition to at least one of Cl and Br. It is preferable. It is because it can be set as the sulfide solid electrolyte material with high Li ion conductivity. X is particularly preferably P. X may contain two or more of the above elements.

When X is P, the sulfide solid electrolyte material preferably contains a PS ₄ ^3- structure as a main component. It is because it can be set as the sulfide solid electrolyte material with little hydrogen sulfide generation amount. “Mainly composed of PS ₄ ^3- structure” means that the ratio of PS ₄ ^3- structure in the total anion structure is 50 mol% or more, and the ratio of PS ₄ ^3- structure is 60 mol% or more. It is preferably 70 mol% or more, more preferably 80 mol% or more, and particularly preferably 90 mol% or more. In particular, the sulfide solid electrolyte material preferably has only a PS ₄ ^3- structure. Note that the ratio of the PS ₄ ^3- structure can be determined by Raman spectroscopy, NMR (for example, ³¹ P MAS NMR), XPS, and the like.

When X is Si, Ge, Al, or B, the sulfide solid electrolyte materials are SiS ₄ ^4- structure, GeS ₄ ^4- structure, AlS ₃ ^3- structure, and BS ₃ ^3- structure, respectively. It is preferable that it contains as a main component. The definition of the main body and the method for measuring the ratio of each structure are the same as described above.

The sulfide solid electrolyte material of the first embodiment is Li ₂ S, a sulfide of X (X is P, Si, Ge, Al, or B), at least one of a Cl-containing compound and a Br-containing compound. It is preferable that it is what uses the raw material composition containing these.

Li ₂ S contained in the raw material composition preferably has few impurities. This is because side reactions can be suppressed. Examples of the method for synthesizing Li ₂ S include the method described in JP-A-7-330312. Furthermore, Li ₂ S is preferably purified using the method described in WO2005 / 040039. On the other hand, examples of the sulfide of X contained in the raw material composition include P ₂ S ₃ , P ₂ S ₅ , SiS ₂ , GeS ₂ , Al ₂ S ₃ , B ₂ S _{3 and the} like.

  The Cl-containing compound contained in the raw material composition is not particularly limited as long as it contains chlorine, and examples thereof include LiCl. Moreover, as a Br containing compound contained in a raw material composition, if it contains a bromine, it will not specifically limit, For example, LiBr etc. can be mentioned.

Also, the sulfide solid electrolyte material is preferably substantially free of Li 2 _S. It is because it can be set as the sulfide solid electrolyte material with little hydrogen sulfide generation amount. Li ₂ S reacts with water to generate hydrogen sulfide. For example, when the proportion of Li ₂ S contained in the raw material composition is large, Li ₂ S tends to remain. “Substantially free of Li ₂ S” can be confirmed by X-ray diffraction. Specifically, when it does not have a Li ₂ S peak (2θ = 27.0 °, 31.2 °, 44.8 °, 53.1 °), it is determined that it does not substantially contain Li ₂ S. can do.

Moreover, it is preferable that the said sulfide solid electrolyte material does not contain bridge | crosslinking sulfur substantially. It is because it can be set as the sulfide solid electrolyte material with little hydrogen sulfide generation amount. “Bridged sulfur” refers to bridged sulfur in a compound obtained by reacting Li ₂ S with the sulfide of X described above. For example, Li ₂ S and _P 2 _{S 5} is bridging sulfur reactions to become _{S 3} PS-PS 3 structure corresponds. Such bridging sulfur easily reacts with water and easily generates hydrogen sulfide. Furthermore, “substantially free of bridging sulfur” can be confirmed by measurement of a Raman spectrum. For example, in the case of a Li ₂ S—P ₂ S ₅ sulfide solid electrolyte material, the peak of the S ₃ P—S—PS ₃ structure usually appears at 402 cm ⁻¹ . Therefore, it is preferable that this peak is not detected. Moreover, the peak of PS ₄ ³⁻ structure usually appears at 417 cm ⁻¹ . In a first embodiment, the intensity _{I 402} at 402 cm ^-1 is preferably smaller than the intensity _{I 417} at 417 cm ^-1. More specifically, the strength I ₄₀₂ is preferably 70% or less, more preferably 50% or less, and even more preferably 35% or less with respect to the strength I ₄₁₇ . As for the sulfide solid electrolyte material other than Li 2 _{S-P 2} S ₅ based, to identify the unit containing the crosslinking sulfur, by measuring the peak of the unit, are substantially free of bridging sulfur It can be judged that there is no.

Also, the sulfide solid electrolyte material, if substantially free of Li 2 _S and bridging sulfur, usually sulfide solid electrolyte material has a composition of ortho-composition or the vicinity thereof. Here, ortho generally refers to one having the highest degree of hydration among oxo acids obtained by hydrating the same oxide. In the first embodiment, the crystal composition in which Li ₂ S is added most in the sulfide is referred to as an ortho composition. For example, Li ₃ PS ₄ corresponds to the ortho composition in the Li ₂ S—P ₂ S ₅ system, Li ₃ AlS ₃ corresponds to the ortho composition in the Li ₂ S—Al ₂ S ₃ system, and Li ₂ S—B _2. In the S ₃ system, Li ₃ BS ₃ corresponds to the ortho composition, in the Li ₂ S—SiS ₂ system, Li ₄ SiS ₄ corresponds to the ortho composition, and in the Li ₂ S—GeS ₂ system, Li ₄ GeS _{4 corresponds} to the ortho composition. Applicable.

For example, in the case of a Li ₂ S—P ₂ S ₅ based sulfide solid electrolyte material, the ratio of Li ₂ S and P ₂ S ₅ to obtain the ortho composition is Li ₂ S: P ₂ S ₅ = 75 on a molar basis. : 25. The same applies to the Li ₂ S—Al ₂ S ₃ -based sulfide solid electrolyte material and the Li ₂ S—B ₂ S ₃ -based sulfide solid electrolyte material. On the other hand, in the case of a Li ₂ S—SiS ₂ -based sulfide solid electrolyte material, the ratio of Li ₂ S and SiS ₂ to obtain the ortho composition is Li ₂ S: SiS ₂ = 66.7: 33.3 on a molar basis. It is. The same applies to the case of a Li ₂ S—GeS ₂ -based sulfide solid electrolyte material.

The raw material composition is, when containing Li ₂ S and _P 2 _{S 5,} the proportion of Li ₂ S to the total of Li ₂ S and _P 2 _{S 5} is preferably in the range of 70 mol% 80 mol% 72 mol% to 78 mol% is more preferable, and 74 mol% to 76 mol% is more preferable. Incidentally, the raw material composition is, when containing Li ₂ S and _Al 2 _{S 3,} which is the same when containing Li ₂ S and _B 2 _{S 3.}

On the other hand, the raw material composition is, when containing Li ₂ S and SiS _2, the ratio of Li ₂ S to the total of Li ₂ S and SiS ₂ is in the range of 62.5mol% ~70.9mol% Is preferable, it is more preferable that it is in the range of 63 mol% to 70 mol%, and it is more preferable that it is in the range of 64 mol% to 68 mol%. The same applies when the raw material composition contains Li ₂ S and GeS ₂ .

Further, the Cl content in the sulfide solid electrolyte material of the first embodiment is not particularly limited, but is 0.4 mol% to 50 mol% with respect to 1 mol of the sulfide solid electrolyte material before addition of Cl. It is preferable to be within the range. If the Cl content is too small, the increase in interfacial resistance may not be sufficiently suppressed, and if the Cl content is too large, the Li ion conductivity of the sulfide solid electrolyte material may be reduced. It is. Since Cl ⁻ has a smaller polarizability than S ^{2 −} , it is considered that the Li ion conductivity of the sulfide solid electrolyte material is lowered. The polarizabilities of Cl ⁻ , Br ⁻ and I ⁻ are 2.96, 4.16 and 6.43, respectively, and the polarizability of S ²⁻ is 5.90. The same applies to the Br content in the sulfide solid electrolyte material of the first embodiment.

  As an example of the form of the sulfide solid electrolyte material of the first embodiment, as shown in FIG. 3A, at least one of Cl and Br is dispersed in the sulfide solid electrolyte material 1 (dispersed sulfide). Solid electrolyte material). On the other hand, as another example of the form of the sulfide solid electrolyte material, as shown in FIG. 3B, the core part 3 having ion conductivity and the surface of the core part 3 are coated, and Cl and Br Examples thereof include a sulfide solid electrolyte material 1 (covered sulfide solid electrolyte material) having a coating portion 4 containing at least one. The dispersion-type sulfide solid electrolyte material has an advantage that it is easy to produce compared to the coating-type sulfide solid electrolyte material. On the other hand, the coated sulfide solid electrolyte material has an advantage that the increase in the interface resistance can be effectively suppressed as compared with the dispersion type sulfide solid electrolyte material.

In addition, the covering-type sulfide solid electrolyte material may have a covering portion formed on at least a part of the surface of the core portion, but the covering portion is preferably formed on a larger area of the surface of the core portion. More preferably, the covering portion is formed on the entire surface of the core portion. Moreover, in FIG.3 (b), it is preferable that the average thickness of the coating | coated part 4 is in the range of 3 nm-100 nm, for example, and it is more preferable that it is in the range of 3 nm-20 nm. Moreover, as said coating | coated part, what is comprised from the Cl containing compound or Br containing compound mentioned above, and what carried out the chlorination process or the bromination process of the said nucleus part, etc. can be mentioned. In addition, the core part may or may not contain Cl and Br as long as it has ion conductivity. In the former case, a dispersion-type sulfide solid electrolyte material can be used as the core, and in the latter case, a conventional sulfide solid electrolyte material (for example, Li ₂ S—P ₂ S ₅ or the like) is used as the core. Can be used.

  The sulfide solid electrolyte material of the first embodiment may be amorphous or crystalline, but is preferably amorphous. When the sulfide solid electrolyte material has a core part and a covering part, the core part may be amorphous or crystalline, but is preferably amorphous. . The amorphous sulfide solid electrolyte material can be obtained, for example, by a mechanical milling method as described later. On the other hand, a crystalline sulfide solid electrolyte material can be obtained, for example, by subjecting an amorphous sulfide solid electrolyte material to a heat treatment.

Examples of the shape of the sulfide solid electrolyte material of the first embodiment include particles. The average particle diameter of the particulate sulfide solid electrolyte material is preferably in the range of 0.1 μm to 50 μm, for example. The sulfide solid electrolyte material preferably has high Li ion conductivity, and the Li ion conductivity at room temperature is preferably 1 × 10 ⁻⁴ S / cm or more, for example, 1 × 10 ⁻³ S. / Cm or more is more preferable.

  The sulfide solid electrolyte material of the first embodiment can be used for any application that requires ionic conductivity. Especially, it is preferable that the said sulfide solid electrolyte material is what is used for a battery. Furthermore, when using the said sulfide solid electrolyte material for a battery, you may use for a positive electrode active material layer (positive electrode body), may be used for a negative electrode active material layer (negative electrode body), and may be used for an electrolyte layer.

(2) Manufacturing method of sulfide solid electrolyte material Next, the manufacturing method of the sulfide solid electrolyte material of 1st embodiment is demonstrated. The method for producing the sulfide solid electrolyte material of the first embodiment is not particularly limited as long as it is a method capable of obtaining the sulfide solid electrolyte material described above. Examples of a method for producing a dispersion-type sulfide solid electrolyte material include Li ₂ S, sulfides of X (X is P, Si, Ge, Al, or B), Cl-containing compounds, and Br-containing compounds. The manufacturing method which has the synthetic | combination process which amorphizes the raw material composition containing at least one can be mentioned.

  Examples of the amorphization method include mechanical milling and melt quenching, and mechanical milling is preferable among them. This is because processing at room temperature is possible, and the manufacturing process can be simplified.

  Mechanical milling is not particularly limited as long as the raw material composition is mixed while applying mechanical energy, and examples thereof include a ball mill, a vibration mill, a turbo mill, a mechanofusion, and a disk mill. Among these, a ball mill is preferable, and a planetary ball mill is particularly preferable. This is because a desired sulfide solid electrolyte material can be obtained efficiently.

  Various conditions of mechanical milling are set so that a desired sulfide solid electrolyte material can be obtained. For example, when a planetary ball mill is used, a raw material composition and grinding balls are added, and the treatment is performed at a predetermined number of revolutions and time. In general, the higher the number of rotations, the faster the production rate of the sulfide solid electrolyte material, and the longer the treatment time, the higher the conversion rate from the raw material composition to the sulfide solid electrolyte material. The rotation speed of the base plate when performing the planetary ball mill is preferably in the range of, for example, 200 rpm to 500 rpm, and more preferably in the range of 250 rpm to 400 rpm. Further, the treatment time when performing the planetary ball mill is preferably in the range of 1 hour to 100 hours, and more preferably in the range of 1 hour to 50 hours.

  The mechanical milling may be dry mechanical milling or wet mechanical milling, but the latter is preferred. This is because the raw material composition can be prevented from adhering to the wall surface of a container or the like, and a sulfide solid electrolyte material with higher amorphousness can be obtained. The liquid used for wet mechanical milling preferably has a property of not generating hydrogen sulfide by the reaction with the raw material composition. Hydrogen sulfide is generated when protons dissociated from liquid molecules react with a raw material composition or a sulfide solid electrolyte material. Therefore, it is preferable that the liquid has an aprotic property that does not generate hydrogen sulfide. In addition, aprotic liquids can be broadly classified into polar aprotic liquids and nonpolar aprotic liquids.

  Although it does not specifically limit as a polar aprotic liquid, For example, Ketones, such as acetone; Nitriles, such as acetonitrile; Amides, such as N, N- dimethylformamide (DMF); Dimethyl sulfoxide (DMSO) And the like.

  An example of a nonpolar aprotic liquid is alkane that is liquid at room temperature (25 ° C.). The alkane may be a chain alkane or a cyclic alkane. The chain alkane preferably has, for example, 5 or more carbon atoms. On the other hand, the upper limit of the carbon number of the chain alkane is not particularly limited as long as it is liquid at room temperature. Specific examples of the chain alkane include pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane, and paraffin. The chain alkane may have a branch. Specific examples of the cyclic alkane include cyclopentane, cyclohexane, cycloheptane, cyclooctane, and cycloparaffin.

  Other examples of nonpolar aprotic liquids include aromatic hydrocarbons such as benzene, toluene and xylene; chain ethers such as diethyl ether and dimethyl ether; cyclic ethers such as tetrohydrofuran; chloroform Alkyl halides such as methyl chloride and methylene chloride; esters such as ethyl acetate; fluorinated benzene, heptane fluoride, 2,3-dihydroperfluoropentane, 1,1,2,2,3,3 Fluorine compounds such as 4-heptafluorocyclopentane can be exemplified. In addition, the addition amount of the said liquid is not specifically limited, What is necessary is just a quantity which can obtain a desired sulfide solid electrolyte material.

  Moreover, in said manufacturing method, you may perform the heat processing process which heat-processes with respect to the sulfide solid electrolyte material obtained at the synthesis | combination process. This is because a crystalline sulfide solid electrolyte material can be obtained. The heating temperature is preferably a temperature equal to or higher than the crystallization temperature.

  On the other hand, as a method for producing a covering-type sulfide solid electrolyte material, there is a production method having a coating step of covering at least one of a Cl-containing compound and a Br-containing compound on the surface of a sulfide solid electrolyte material that becomes a core. be able to. In addition, by injecting Cl-containing gas (for example, chlorine gas) or Br-containing gas (for example, bromine gas) onto the surface of the sulfide solid electrolyte material that becomes the core, the surface of the core is chlorinated or brominated, A coated sulfide solid electrolyte material can also be obtained.

2. Second Embodiment Next, a second embodiment of the sulfide solid electrolyte material of the present invention will be described. The sulfide solid electrolyte material of the second embodiment has a core part having ion conductivity and a coating part covering the surface of the core part, and the coating part contains I. Is.

  According to the second embodiment, since the covering portion contains I, a sulfide solid electrolyte material in which suppression of increase in interface resistance and suppression of increase in bulk resistance are compatible can be obtained. Here, Non-Patent Documents 1 and 2 described above disclose sulfide solid electrolyte materials containing iodine (I). However, these documents describe a configuration in which the covering portion covering the core portion has iodine, and that iodine is effective for coexistence of suppression of increase in interface resistance and suppression of increase in bulk resistance. Absent.

In addition, the sulfide solid electrolyte material of the second embodiment covers the core 3 having ion conductivity and the surface of the core 3 in the same manner as the sulfide solid electrolyte material 1 shown in FIG. , I containing the coating portion 4. As long as the core part 3 has ionic conductivity, the core part 3 may or may not have I. In the former case, a dispersed sulfide solid electrolyte material in which I is dispersed can be used as the core portion. In the latter case, a conventional sulfide solid electrolyte material (for example, Li ₂ S—P ₂₎ can be used as the core portion. can be used S _5, etc.).

  The dispersion-type sulfide solid electrolyte material in which I is dispersed is the same as the matter described in “1. First embodiment” except that I is used instead of Cl and Br. Examples of the I-containing compound include LiI. The covering-type sulfide solid electrolyte material is the same as that described in “1. First embodiment” except that I is used instead of Cl and Br. The sulfide solid electrolyte material of the second embodiment may have the characteristics of the sulfide solid electrolyte material of the first embodiment.

B. Next, the positive electrode body of the present invention will be described. The positive electrode body of the present invention is a positive electrode body containing a positive electrode active material and a sulfide solid electrolyte material that reacts with the positive electrode active material to form a high resistance layer, wherein the sulfide solid electrolyte material is Cl, It contains at least one of Br and I.

  According to the present invention, since the sulfide solid electrolyte material contains at least one of Cl, Br, and I, a positive electrode body that achieves both suppression of increase in interface resistance and suppression of increase in bulk resistance, can do.

FIG. 4 is a schematic view showing an example of the positive electrode body of the present invention. A positive electrode body 11 shown in FIG. 4 contains a positive electrode active material 2a and a sulfide solid electrolyte material 1 that reacts with the positive electrode active material 2a to form a high resistance layer (not shown). The positive electrode body of the present invention is characterized in that the sulfide solid electrolyte material 1 contains at least one of Cl, Br, and I.
Hereinafter, the positive electrode body of the present invention will be described for each configuration.

1. Sulfide solid electrolyte material The sulfide solid electrolyte material in the present invention reacts with a positive electrode active material to form a high resistance layer. Formation of the high resistance layer can be confirmed by a transmission electron microscope (TEM) and energy dispersive X-ray spectroscopy (EDX).

  The sulfide solid electrolyte material in the present invention may be a dispersion-type sulfide solid electrolyte material as long as it contains at least one of Cl, Br, and I, and may be a coated sulfide solid electrolyte material. There may be. The sulfide solid electrolyte material is the same as that described in “A. Sulfide solid electrolyte material”. Here, in “A. Sulfide Solid Electrolyte Material 2. Second Embodiment”, a covering type sulfide solid electrolyte material containing I will be described, and a dispersion type sulfide solid electrolyte material containing I will be described. However, the sulfide solid electrolyte material in the present invention may be a dispersion-type sulfide solid electrolyte material containing I. The reason is as follows.

  That is, conventionally, it is not known to use a dispersion-type sulfide solid electrolyte material containing I for the positive electrode body. Non-Patent Documents 1 and 2 disclose a dispersion-type sulfide solid electrolyte material using LiI as a starting material, but LiI has a low potential at which an oxidation reaction occurs ([0028], [0028] of [Patent Document 2] [0029] (Refer to paragraph), it has never been used for a positive electrode body. However, in the present invention, focusing on achieving both suppression of increase in interface resistance and suppression of increase in bulk resistance, even if some decomposition of LiI or the like occurs, it is determined that the obtained effect is greater. The configuration as described above is adopted. Further, in the case of a dispersion-type sulfide solid electrolyte material containing I, even when LiI is used as a starting material, there is a case where I is dispersed and, as a result, is not decomposed at a normal oxidation potential of LiI. . Further, from the viewpoint of reducing the influence of decomposition of LiI or the like, the positive electrode active material preferably has a coating layer described later.

  The content of the sulfide solid electrolyte material in the positive electrode body is, for example, in the range of 0.1% by volume to 80% by volume, especially in the range of 1% by volume to 60% by volume, in particular, 10% by volume to 50%. It is preferable to be within the range of volume%.

2. Next, the positive electrode active material in the present invention will be described. The positive electrode active material in the present invention is not particularly limited as long as it reacts with the above-described sulfide solid electrolyte material to form a high resistance layer, but an oxide positive electrode active material is particularly preferable. Since the metal element in the oxide positive electrode active material reacts more easily with sulfur than oxygen, it reacts with sulfur in the sulfide solid electrolyte material to form sulfur metal. It is considered that the sulfur metal itself becomes a high resistance layer, and metal ions and sulfur ions are deficient (decomposed) near the interface between the oxide positive electrode active material and the sulfide solid electrolyte material. Moreover, it can be set as a positive electrode body with a high energy density by using an oxide positive electrode active material.

As an oxide positive electrode active material used for a lithium solid state battery, for example, a general formula Li _x M _y O _z (M is a transition metal element, x = 0.02 to 2.2, y = 1 to 2, z = 1.4-4) can be mentioned as the positive electrode active material. In the above general formula, M is preferably at least one selected from the group consisting of Co, Mn, Ni, V, Fe and Si, and is at least one selected from the group consisting of Co, Ni and Mn. It is more preferable. Examples of the oxide positive electrode active material include rock salt layered active materials such as LiCoO ₂ , LiMnO ₂ , LiNiO ₂ , LiVO ₂ , LiNi _1/3 Co _1/3 Mn _1/3 O ₂ , LiMn ₂ O ₄ , Li Examples thereof include spinel active materials such as (Ni _0.5 Mn _1.5 ) O ₄ . As the oxide positive electrode active _material, it may be used _{Li 2 FeSiO 4, Li 2 MnSiO} 4 , _{etc., LiFePO 4, LiMnPO 4, LiNiPO} 4, may be used an olivine active material LiCuPO ₄ or the like.

The positive electrode active material in the present invention is preferably an active material having a potential of 2.8 V (vs Li) or higher. In paragraph [0028] of Patent Document 2, it is described that LiI has an oxidation reaction potential of about 3 V, but according to the Nernst equation, an oxidation reaction occurs at 2.8 V.
E = ΔU _elec /γF=270.29×10 ³ /1×96450=2.8 V (vs Li)
Therefore, combining an active material having a potential of 2.8 V (vs Li) or higher with a sulfide solid electrolyte material using LiI as a starting material has not been conventionally performed. In particular, the potential of the positive electrode active material is preferably 3.0 V (vs Li) or more.

Moreover, as shown in FIG. 5, it is preferable that the oxide coating layer 5 is formed on the surface of the positive electrode active material 2a. It is because it can further suppress that a positive electrode active material and a sulfide solid electrolyte material react, and a high resistance layer is formed. In the present invention, the oxide is preferably an ion conductive oxide. It is because the resistance at the surface of the positive electrode active material can be lowered by ions conducting inside the ion conductive oxide. Thereby, a positive electrode body with low interface resistance can be obtained. When the positive electrode body of the present invention is used for a lithium solid state battery, the ion conductive oxide preferably contains an Li element, an M element (M is a metal element), and an O element. The M is not particularly limited, and examples thereof include Nb, Ti, and Zr. Furthermore, specific examples of such an ion conductive oxide include LiNbO ₃ , Li ₄ Ti ₅ O ₁₂ , LiTiO ₃ , Li ₂ ZrO _{3 and the} like. On the other hand, the oxide may not have ionic conductivity. When such an oxide is used, the initial characteristic of the interface resistance cannot be improved, but the formation of the high resistance layer can be suppressed. Examples of the oxide having no ion conductivity include TiO ₂ and ZrO ₂ .

  The thickness of the coat layer is, for example, preferably in the range of 1 nm to 500 nm, and more preferably in the range of 2 nm to 100 nm. This is because the reaction between the positive electrode active material and the sulfide solid electrolyte material can be sufficiently suppressed within the above range. The coating layer preferably covers most of the surface of the positive electrode active material. Specifically, the coverage is preferably 40% or more, more preferably 70% or more, and 90% or more. More preferably. Examples of the method for forming the coat layer on the surface of the positive electrode active material include a rolling fluid coating method (sol-gel method), a mechanofusion method, a CVD method, and a PVD method.

  Examples of the shape of the positive electrode active material include a particle shape, and among them, a spherical shape or an elliptical shape is preferable. Moreover, when a positive electrode active material is a particle shape, it is preferable that the average particle diameter exists in the range of 0.1 micrometer-50 micrometers, for example. Moreover, it is preferable that the content of the positive electrode active material in the positive electrode body is, for example, in the range of 10% by volume to 99% by volume, and more preferably in the range of 20% by volume to 99% by volume.

3. Positive electrode body The positive electrode body of the present invention may further contain at least one of a conductive material and a binder in addition to the positive electrode active material and the sulfide solid electrolyte material. Examples of the conductive material include acetylene black, ketjen black, and carbon fiber. Examples of the binder include fluorine-containing binders such as PTFE and PVDF. The thickness of the positive electrode body is preferably in the range of 0.1 μm to 1000 μm, for example. Moreover, as a formation method of a positive electrode body, the method etc. which compression-mold the material which comprises a positive electrode body can be mentioned, for example. In addition, the positive electrode body is usually used for a battery, and is preferably used for a solid battery.

C. Next, the lithium solid state battery of the present invention will be described. The lithium solid state battery of the present invention is a lithium solid state battery having a positive electrode active material layer, a negative electrode active material layer, and a solid electrolyte layer formed between the positive electrode active material layer and the negative electrode active material layer, The positive electrode active material layer is the positive electrode body described above.

  According to the present invention, by using the positive electrode body described above as the positive electrode active material layer, it is possible to provide a lithium solid state battery that achieves both suppression of increase in interface resistance and suppression of increase in bulk resistance.

FIG. 6 is a schematic cross-sectional view showing an example of the lithium solid state battery of the present invention. 6 includes a positive electrode active material layer 11 containing a positive electrode active material, a negative electrode active material layer 12 containing a negative electrode active material, and between the positive electrode active material layer 11 and the negative electrode active material layer 12. The solid electrolyte layer 13 formed on the positive electrode, the positive electrode current collector 14 for collecting current of the positive electrode active material layer 11, the negative electrode current collector 15 for collecting current of the negative electrode active material layer 12, and these members are housed. The battery case 16 is included. In the present invention, the positive electrode active material layer 11 is characterized by using the positive electrode body described in “B.
Hereinafter, the lithium solid state battery of the present invention will be described for each configuration.

1. Positive Electrode Active Material Layer The positive electrode active material layer in the present invention is the same as the content described in “B.

2. Next, the negative electrode active material layer in the present invention will be described. The negative electrode active material layer in the present invention is a layer containing at least a negative electrode active material, and may further contain at least one of a solid electrolyte material, a conductive material, and a binder as necessary.

  In the present invention, the solid electrolyte material contained in the negative electrode active material layer is preferably the sulfide solid electrolyte material described in the above “A. Sulfide solid electrolyte material”. The content of the sulfide solid electrolyte material in the negative electrode active material layer is, for example, in the range of 0.1% by volume to 80% by volume, especially in the range of 1% by volume to 60% by volume, in particular, 10% by volume to It is preferably within the range of 50% by volume.

  Examples of the negative electrode active material include a metal active material and a carbon active material. Examples of the metal active material include In, Al, Si, and Sn. On the other hand, examples of the carbon active material include mesocarbon microbeads (MCMB), highly oriented graphite (HOPG), hard carbon, and soft carbon. Further, the content of the negative electrode active material in the negative electrode active material layer is, for example, preferably in the range of 10% by volume to 99% by volume, and more preferably in the range of 20% by volume to 99% by volume.

  Examples of the conductive material include acetylene black, ketjen black, and carbon fiber. Examples of the binder include fluorine-containing binders such as PTFE and PVDF. The thickness of the negative electrode active material layer is preferably in the range of 0.1 μm to 1000 μm, for example.

3. Next, the solid electrolyte layer in the present invention will be described. The solid electrolyte layer in the present invention is a layer formed between the positive electrode active material layer and the negative electrode active material layer, and is a layer composed of a solid electrolyte material. The solid electrolyte material contained in the solid electrolyte layer is not particularly limited as long as it has Li ion conductivity.

  In the present invention, the solid electrolyte material contained in the solid electrolyte layer is preferably the sulfide solid electrolyte material described in the above “A. Sulfide solid electrolyte material”. This is because a high resistance layer can be prevented from being formed at the interface with the positive electrode active material layer. The content of the sulfide solid electrolyte material in the solid electrolyte layer is not particularly limited as long as a desired insulating property can be obtained. For example, within the range of 10% by volume to 100% by volume, It is preferably within the range of 50% to 100% by volume. In particular, in the present invention, it is preferable that the solid electrolyte layer is composed only of the sulfide solid electrolyte material.

  The solid electrolyte layer may contain a binder. This is because a solid electrolyte layer having flexibility can be obtained by containing a binder. Examples of the binder include fluorine-containing binders such as PTFE and PVDF. The thickness of the solid electrolyte layer is, for example, preferably in the range of 0.1 μm to 1000 μm, and more preferably in the range of 0.1 μm to 300 μm.

4). Other Configurations The lithium solid state battery of the present invention has at least the positive electrode active material layer, the negative electrode active material layer, and the solid electrolyte layer described above. Furthermore, it usually has a positive electrode current collector for collecting current of the positive electrode active material layer and a negative electrode current collector for collecting current of the negative electrode active material layer. Examples of the material for the positive electrode current collector include SUS, aluminum, nickel, iron, titanium, and carbon. Among them, SUS is preferable. On the other hand, examples of the material for the negative electrode current collector include SUS, copper, nickel, and carbon. Among them, SUS is preferable. In addition, the thickness and shape of the positive electrode current collector and the negative electrode current collector are preferably appropriately selected according to the use of the lithium solid state battery. Moreover, the battery case of a general lithium solid battery can be used for the battery case used for this invention. Examples of the battery case include a SUS battery case.

5. Lithium solid battery The lithium solid battery of the present invention may be a primary battery or a secondary battery, and among these, a secondary battery is preferable. This is because it can be repeatedly charged and discharged and is useful, for example, as a vehicle-mounted battery. Examples of the shape of the lithium solid state battery of the present invention include a coin type, a laminate type, a cylindrical type, and a square type.

  Moreover, the manufacturing method of the lithium solid state battery of the present invention is not particularly limited as long as it is a method capable of obtaining the above-described lithium solid state battery, and the same method as a general lithium solid state battery manufacturing method is used. be able to. As an example of a method for producing a lithium solid state battery, a power generation element is manufactured by sequentially pressing a material constituting the positive electrode active material layer, a material constituting the solid electrolyte layer, and a material constituting the negative electrode active material layer, A method of storing the power generation element in the battery case and caulking the battery case can be exemplified. The present invention also provides a negative electrode active material layer (negative electrode body) and a solid electrolyte layer each containing the sulfide solid electrolyte material described in “A. Sulfide solid electrolyte material”. You can also.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

  Hereinafter, the present invention will be described in more detail with reference to examples.

[Example 1]
(1) Synthesis of sulfide solid electrolyte material Lithium sulfide (Li ₂ S), diphosphorus pentasulfide (P ₂ S ₅ ) and lithium chloride (LiCl) were used as starting materials. Next, in a glove box under an Ar atmosphere (dew point −70 ° C.), Li ₂ S and P ₂ S ₅ have a molar ratio of 75Li ₂ S · 25P ₂ S ₅ (Li ₃ PS ₄ , ortho composition). Weighed as follows. Next, LiCl was weighed so that a molar ratio of Li ₃ PS ₄ : LiCl = 100: 0.43 was obtained. 2 g of this mixture is charged into a planetary ball mill container (45 cc, made of ZrO ₂ ), dehydrated heptane (moisture content of 30 ppm or less, 4 g) is charged, and ZrO ₂ balls (φ = 5 mm, 53 g) are charged. The container was completely sealed (Ar atmosphere). This container was attached to a planetary ball mill (P7 made by Fritsch), and mechanical milling was performed at a base plate rotation speed of 370 rpm for 40 hours. Thereafter, the obtained sample was vacuum-dried to obtain a glassy sulfide solid electrolyte material.

(2) Production of Lithium Solid Battery First, the obtained sulfide solid electrolyte material and LiCoO ₂ (positive electrode active material) coated with LiNbO ₃ having a thickness of 7 nm are mixed with the positive electrode active material: sulfide solid electrolyte material = 7. : The weight ratio of 3 was mixed, and the positive electrode compound material was obtained. _Next, a 75Li 2 _S · _25P 2 S ₅ amorphous form (sulfide solid electrolyte material), and graphite (negative electrode active material), the negative electrode active material: sulfide solid electrolyte material = 5: in a weight ratio of 5 By mixing, a negative electrode mixture was obtained. A lithium solid state battery was obtained by using the obtained positive electrode mixture and negative electrode mixture and the 75Li ₂ S · 25P ₂ S ₅ amorphous material prepared as the solid electrolyte layer forming material.

[Example 2]
A lithium solid state battery was obtained in the same manner as in Example 1 except that the ratio of Li ₃ PS ₄ and LiCl was changed to a molar ratio of Li ₃ PS ₄ : LiCl = 100: 4.3.

[Example 3]
A lithium solid state battery was obtained in the same manner as in Example 1 except that LiI was used instead of LiCl.

[Example 4]
A lithium solid state battery was obtained in the same manner as in Example 2 except that LiI was used instead of LiCl.

[Example 5]
A lithium solid state battery was obtained in the same manner as in Example 1 except that LiI was used instead of LiCl and the molar ratio was changed to Li ₃ PS ₄ : LiI = 100: 43.

[Comparative Example 1]
A lithium solid state battery was obtained in the same manner as in Example 1 except that LiCl was not used.

[Comparative Example 2]
Instead of LiCl, LiPF ₆ was used, and the ratio of Li ₃ PS ₄ and LiPF ₆ was changed to a molar ratio of Li ₃ PS ₄ : LiPF ₆ = 100: 0.7. Thus, a lithium solid state battery was obtained.

[Comparative Example 3]
A lithium solid state battery was obtained in the same manner as in Comparative Example 2 except that the ratio of Li ₃ PS ₄ and LiPF ₆ was changed to a molar ratio of Li ₃ PS ₄ : LiPF ₆ = 100: 6.

[Evaluation]
(Impedance measurement)
Impedance measurement was performed using the lithium solid state batteries obtained in Examples 1 to 4 and Comparative Examples 1 to 3. First, the lithium solid battery was charged. The charging condition was a condition of charging up to 3.7 V with CCCV. After charging, the interface resistance (initial) and the bulk resistance (initial) were determined by impedance measurement using the AC impedance method. Solartron 1260 was used for the measurement, and the measurement conditions were a voltage amplitude of ± 10 mV, a measurement frequency of 1 MHz to 0.1 Hz, and 25 ° C. Thereafter, the lithium solid state battery after the impedance measurement was stored in an environment at 60 ° C. for 20 days. After storage, it was placed in an environment at 25 ° C. for 2 hours, and subsequently, interface resistance (after high temperature storage) and bulk resistance (after high temperature storage) were determined by impedance measurement under the same conditions as described above. The results are shown in FIG.

  In FIG. 7 and Table 1, when Comparative Examples 1 to 3 were compared, it was confirmed that the addition of F suppresses an increase in interface resistance after high-temperature storage. On the other hand, the increase of bulk resistance became remarkable by adding F. In contrast, in Examples 1 to 4, it was confirmed that an increase in interface resistance after high-temperature storage was suppressed, and that an increase in bulk resistance after high-temperature storage could be suppressed.

(Evaluation of charge / discharge cycle characteristics)
Using the lithium solid state batteries obtained in Example 5 and Comparative Example 1, the charge / discharge cycle characteristics were evaluated. The charge / discharge conditions were 0.1 C, CC charge to 4.1 V, and CC discharge to 3.0 V. The result is shown in FIG. As shown in FIG. 8, Example 5 was confirmed to have a higher capacity retention rate and better cycle characteristics than Comparative Example 1.

(Effect of Li ion conductivity by fluorine addition)
Using the sulfide solid electrolyte material synthesized in Comparative Examples 1 to 3, the influence of Li ion conductivity due to the addition of fluorine was examined. Specifically, the Li ion conductivity of the sulfide solid electrolyte material synthesized in Comparative Examples 1 to 3 was measured by the AC impedance method. Solartron 1260 was used for the measurement, and the measurement conditions were a voltage amplitude of ± 5 mV, a measurement frequency of 1 MHz to 0.1 Hz, and 25 ° C. The result is shown in FIG. As shown in FIG. 9, it was confirmed that the Li ion conductivity decreases as the fluorine addition amount increases.

[Reference Example 1]
The structural stability of the structure in which S in Li ₃ PS ₄ was replaced with F was calculated by the molecular orbital method (Gaussian03: Mp2 / 6-311G (d, p)). Specifically, the structural stability was calculated for Li ₃ PS ₃ F, Li ₂ PS ₃ F, Li ₂ PS ₂ F ₂ , LiPS ₂ F ₂ , LiPSF ₃ , and PSF ₃ . As a result, it was found that Li ₃ PS ₃ F can exist stably, suggesting that PS destroys the PS ₄ ^3- structure.

[Reference Examples 2 to 4]
Structural stability was calculated for a structure in which S of Li ₃ PS ₄ was substituted with Cl, Br, and I, respectively, by the molecular orbital method (Gaussian03: Mp2 / 6-311G (d, p)). The target substitution structure is the same as in Reference Example 1. As a result, it was found that none of the structures could exist stably, suggesting that the PS ₄ ³⁻ structure was not destroyed by Cl, Br, and I.

DESCRIPTION OF SYMBOLS 1 ... Sulfide solid electrolyte material 2 ... Electrode active material 2a ... Positive electrode active material 3 ... Core part 4 ... Covering part 11 ... Positive electrode active material layer 12 ... Negative electrode active material layer 13 ... Solid electrolyte layer 14 ... Positive electrode collector 15 ... Negative electrode current collector 16 ... Battery case 20 ... Lithium solid state battery

Claims (4)

A sulfide solid electrolyte material for a lithium solid state battery containing Li, Si , a halogen element which is at least one of Cl, Br and I, and S ,
Containing SiS ₄ ⁴⁻ structure as the main component, Li ₂ S and no bridging sulfur,
The halogen element are distributed around the SiS ₄ ^4-structure,
Content of the halogen element is in a range of 0.4 mol% to 50 mol% with respect to 1 mol of the sulfide solid electrolyte material for lithium solid battery before addition of the halogen element, for lithium solid battery Sulfide solid electrolyte material. A sulfide solid electrolyte material for a lithium solid state battery containing Li, Ge , a halogen element which is at least one of Cl, Br and I, and S ,
Containing GeS ₄ ^4- structure as the main component, Li ₂ S and no bridging sulfur,
The halogen element are distributed around the GeS ₄ ^4-structure,
Content of the halogen element is in a range of 0.4 mol% to 50 mol% with respect to 1 mol of the sulfide solid electrolyte material for lithium solid battery before addition of the halogen element, for lithium solid battery Sulfide solid electrolyte material. A positive electrode body for a lithium solid battery containing an oxide positive electrode active material and a sulfide solid electrolyte material,
The positive electrode body for a lithium solid battery, wherein the sulfide solid electrolyte material is the sulfide solid electrolyte material for a lithium solid battery according to claim 1 or 2. A lithium solid state battery having a positive electrode active material layer, a negative electrode active material layer, and a solid electrolyte layer formed between the positive electrode active material layer and the negative electrode active material layer,
The lithium solid battery, wherein the positive electrode active material layer is the positive electrode body for a lithium solid battery according to claim 3.

Images