JP2019071210A - Method for manufacturing inorganic material - Google Patents

Abstract

To provide a method for manufacturing an inorganic material, which allows the vitrification of an inorganic composition to be conducted in a shorter time, and which can shorten a manufacturing time.SOLUTION: A method for manufacturing an inorganic material according to the present invention is one for manufacturing an inorganic material (A) which can be obtained from two or more kinds of inorganic compounds (A1). The method comprises: a preparation step of preparing a raw material inorganic composition (A2) including the two or more kinds of inorganic compounds (A1); an intermediate production step of heating the raw material inorganic composition (A2) at a temperature lower than a crystallization temperature of the inorganic material (A), thereby causing a reaction of the two or more kinds of inorganic compounds (A1) to obtain an intermediate inorganic composition (A3); and a vitrification step of performing a mechanical treatment on the intermediate inorganic composition (A3) thus obtained, thereby causing a reaction of the intermediate inorganic composition (A3) and the vitrification thereof to obtain the inorganic material (A).SELECTED DRAWING: None

Description

  The present invention relates to a method of producing an inorganic material.

  Lithium ion batteries are generally used as a power source for small portable devices such as mobile phones and notebook computers. Also, recently, in addition to small portable devices, lithium ion batteries have also begun to be used as power sources for electric vehicles and power storage.

  Currently commercially available lithium ion batteries use an electrolyte containing a flammable organic solvent. On the other hand, a lithium ion battery (hereinafter, also referred to as an all solid lithium ion battery) in which the battery is completely solidified by changing the electrolyte solution to a solid electrolyte does not use a flammable organic solvent in the battery. Can be simplified, and is considered to be excellent in manufacturing cost and productivity.

  As a solid electrolyte material used for such a solid electrolyte, for example, a sulfide-based solid electrolyte material is known.

Patent Document 1 (Japanese Patent Laid-Open No. 2016-27545) has a peak at a position of 2θ = 29.86 ° ± 1.00 ° in X-ray diffraction measurement using a CuKα ray, Li 2 _{y + 3} PS ₄ (0 A sulfide-based solid electrolyte material is described which is characterized by having a composition of 1 ≦ y ≦ 0.175).

JP, 2016-27545, A

A sulfide-based inorganic solid electrolyte material as described in Patent Document 1 generally includes an inorganic composition containing two or more inorganic compounds as raw materials of the inorganic solid electrolyte material, such as a mechanical milling method or the like. It is obtained through the process of vitrification by mechanical processing using a method.
However, according to the study of the present inventors, it has been revealed that the step of vitrifying the inorganic composition by mechanical treatment is very time-consuming and the productivity is poor. That is, the method for producing an inorganic material including the step of vitrifying the above-mentioned inorganic composition by mechanical treatment is not suitable for industrial production.

  The present invention has been made in view of the above circumstances, and provides a method of producing an inorganic material capable of vitrifying an inorganic composition in a shorter time and shortening the production time. .

  The present inventors diligently studied to achieve the above object. As a result, the raw inorganic composition is heated at a temperature lower than the crystallization temperature of the target inorganic material to obtain an intermediate inorganic composition and then the vitrification process is performed to shorten the vitrification process of the inorganic composition. It has been found that it is possible to complete the present invention.

According to the invention
It is a manufacturing method for manufacturing an inorganic material (A) obtained by two or more kinds of inorganic compounds (A1),
A preparation step of preparing a raw material inorganic composition (A2) containing the two or more types of inorganic compounds (A1),
By heating the above raw material inorganic composition (A2) at a temperature lower than the crystallization temperature of the above inorganic material (A), the above two or more kinds of inorganic compounds (A1) are reacted to produce an intermediate inorganic composition (A3) Obtaining intermediates,
Vitrifying the obtained intermediate inorganic composition (A3) by mechanical treatment to cause the intermediate inorganic composition (A3) to react and vitrify to obtain the inorganic material (A);
A method of producing an inorganic material comprising the

  ADVANTAGE OF THE INVENTION According to this invention, vitrification of an inorganic composition can be performed in a short time, and the manufacturing method of the inorganic material which can shorten manufacturing time can be provided.

It is a figure which shows the X-ray-diffraction spectrum of the inorganic composition before a mechanochemical process in an Example and a comparative example. It is a figure which shows the X-ray-diffraction spectrum of the inorganic composition after performing a mechanochemical process for 100 hours in an Example and a comparative example. It is a figure which shows the X-ray-diffraction spectrum of the inorganic composition after performing a mechanochemical process for 200 hours in an Example and a comparative example. It is a figure which shows the X-ray-diffraction spectrum of the inorganic composition after performing mechanochemical processing for a predetermined period in an Example. It is a figure which shows the X-ray-diffraction spectrum of the inorganic composition in Example 9 (a) and Example 10 (b). It is a figure which shows the X-ray-diffraction spectrum of the inorganic composition in the comparative example 2. FIG. It is a figure which shows the X-ray-diffraction spectrum of the intermediate | middle inorganic composition in a reference example.

  Hereinafter, embodiments of the present invention will be described using the drawings. In all the drawings, the same components are denoted by the same reference numerals, and the description thereof is appropriately omitted. Unless otherwise noted, “A to B” in the numerical range represents A or more and B or less.

First, a method of manufacturing the inorganic material according to the present embodiment will be described.
The method for producing an inorganic material according to the present embodiment is a method for producing an inorganic material (A) obtained by two or more types of inorganic compounds (A1), and the method for producing two or more types of inorganic compounds (A1) A preparation step of preparing a raw material inorganic composition (A2) containing the raw material inorganic composition (A2), and heating the raw material inorganic composition (A2) at a temperature lower than the crystallization temperature of the inorganic material (A) The intermediate inorganic composition (A3) is reacted and vitrified by mechanically treating the intermediate inorganic composition (A3) by mechanically treating the intermediate inorganic composition (A3) with the intermediate formation step of obtaining the intermediate inorganic composition (A3). And vitrifying to obtain the inorganic material (A).

According to the method of producing an inorganic material according to the present embodiment, the step of vitrifying the inorganic composition can be significantly shortened as compared with the conventional method of production, and as a result, the production time of the inorganic material (A) Can be shortened. Although the reason for this is not clear, the following reason is inferred.
First, when the raw material inorganic composition (A2) containing two or more kinds of inorganic compounds (A1) is heated at a temperature lower than the crystallization temperature of the target inorganic material (A), energy more than activation energy is easily given. As a result, the intermediate inorganic composition (A3), which is in a low energy state with the release of energy, can be obtained in a short time. And since the free energy of the intermediate inorganic composition (A3) and the free energy of the inorganic material (A) in the glassy state which is metastable state are close, the intermediate inorganic composition (A3) is metastable state with smaller energy It can be made into an inorganic material (A) in a glass state.
From the above reasons, before the vitrification step, the raw inorganic composition (A2) is heated at a temperature lower than the crystallization temperature of the target inorganic material (A), and the intermediate inorganic composition ( By setting it as A3), it is considered that the metastable glass state can be obtained with less energy, and the step of vitrifying the inorganic composition can be significantly shortened compared to the conventional manufacturing method. .

  Each step will be described in detail below.

(Preparation step of preparing the raw material inorganic composition (A2))
First, a raw material inorganic composition (A2) containing two or more kinds of inorganic compounds (A1) is prepared.
As the inorganic compound (A1), two or more compounds that chemically react with each other by mechanical treatment to form a new inorganic material are used. These inorganic compounds (A1) can be suitably selected according to the target inorganic material (A).
In the present embodiment, “to generate a new inorganic material by causing a chemical reaction with each other by mechanical treatment” means that a chemical reaction between two or more kinds of coexisting inorganic compounds is caused by a mechanical treatment, and thereby a new inorganic material is generated. It means that the material is formed.

The raw material inorganic composition (A2) is obtained, for example, by mixing two or more inorganic compounds (A1) as raw materials at a predetermined molar ratio so that the target inorganic material (A) has a desired composition ratio. You can get it. Here, the mixing ratio of each inorganic compound (A1) in the raw material inorganic composition (A2) is adjusted so that the target inorganic material (A) to be obtained has a desired composition ratio.
The method for mixing two or more inorganic compounds (A1) is not particularly limited as long as it is a mixing method capable of uniformly mixing each inorganic compound (A1), but, for example, a ball mill, bead mill, vibration mill, impact pulverizer, mixer (Pug mixer, ribbon mixer, tumbler mixer, drum mixer, V-type mixer etc.), kneader, twin-screw kneader, air stream crusher etc. can be used for mixing.
The mixing conditions such as stirring speed, processing time, temperature, reaction pressure, gravity acceleration applied to the mixture when mixing each inorganic compound (A1) can be appropriately determined depending on the amount of the mixture to be processed.

Although it does not specifically limit as an inorganic material (A) which concerns on this embodiment, For example, an inorganic solid electrolyte material, a positive electrode active material, a negative electrode active material etc. are mentioned.
The inorganic solid electrolyte material is not particularly limited, and examples thereof include a sulfide-based inorganic solid electrolyte material, an oxide-based inorganic solid electrolyte material, and other lithium-based inorganic solid electrolyte materials. Among these, sulfide-based inorganic solid electrolyte materials are preferable.
Further, the inorganic solid electrolyte material is not particularly limited, and examples thereof include those used for a solid electrolyte layer constituting an all solid lithium ion battery.

Examples of the sulfide-based inorganic solid electrolyte material include Li ₂ S-P ₂ S ₅ material, Li ₂ S-SiS ₂ material, Li ₂ S-GeS ₂ material, Li ₂ S-Al ₂ S ₃ material, Li _{2 S-SiS 2 -Li 3 PO} 4 _{material, Li 2 S-P 2 S} 5 -GeS 2 _{material, Li 2 S-Li 2 O} -P 2 S 5 -SiS 2 _material, Li 2 _S-GeS 2 -P ₂ S ₅ -SiS _{2 material, Li 2 S-SnS 2 -P} 2 S 5 -SiS 2 _{material, Li 2 S-P 2 S} 5 -Li 3 N _{materials, Li 2 S 2 + X -P} 4 S 3 material, Li ₂ SP ₂ S ₅ -P ₄ S ₃ materials and the like can be mentioned.
Among these, a Li ₂ S—P ₂ S ₅ material is preferable from the viewpoint of excellent lithium ion conductivity and stability that does not cause decomposition or the like in a wide voltage range. Here, for example, with the Li ₂ S—P ₂ S ₅ material, an inorganic composition containing at least Li ₂ S (lithium sulfide) and P ₂ S ₅ (phosphorus sulfide) is chemically reacted with each other by mechanical processing. Means the inorganic material obtained by
Here, in the present embodiment, lithium sulfide is also included in lithium sulfide.

Examples of the oxide-based inorganic solid electrolyte material, for _{example, LiTi 2 (PO 4) 3} , LiZr 2 (PO 4) 3, LiGe 2 (PO 4) 3 , etc. NASICON _{type, (La 0.5} + _{x Li} 0.5 _-3X) TiO ₃ or the like _{perovskite, Li 2 O-P 2 O} 5 _{material, Li 2 O-P 2 O} 5 -Li 3 N material, and the like.
Examples of other lithium-based inorganic solid electrolyte materials include LiPON, LiNbO ₃ , LiTaO ₃ , Li ₃ PO ₄ , LiPO _4-x N _x (x is 0 <x ≦ 1), LiN, LiI, LISICON, etc. Be
Furthermore, glass ceramics obtained by depositing crystals of these inorganic solid electrolytes can also be used as the inorganic solid electrolyte material.

The sulfide-based inorganic solid electrolyte material according to the present embodiment preferably has lithium ion conductivity and contains Li, P and S as constituent elements.
Here, when the target inorganic material (A) contains a sulfide-based inorganic solid electrolyte material, it is preferable that at least lithium sulfide and phosphorus sulfide be contained as the two or more inorganic compounds (A1) as the raw materials.

The lithium sulfide used as the raw material is not particularly limited, and commercially available lithium sulfide may be used. For example, lithium sulfide obtained by the reaction of lithium hydroxide and hydrogen sulfide may be used. From the viewpoint of obtaining a high purity sulfide-based inorganic solid electrolyte material and from the viewpoint of suppressing side reactions, it is preferable to use lithium sulfide with few impurities.
Here, in the present embodiment, lithium sulfide is also included in lithium sulfide.

The phosphorus sulfide used as the raw material is not particularly limited, and commercially available phosphorus sulfide (for example, P ₂ S ₅ , P ₄ S ₃ , P ₄ S ₇ , P ₄ S _{5 and the} like) can be used. From the viewpoint of obtaining a high-purity sulfide-based inorganic solid electrolyte material and from the viewpoint of suppressing side reactions, it is preferable to use phosphorus sulfide with few impurities. Also, instead of phosphorus sulfide, it is also possible to use elemental phosphorus (P) and elemental sulfur (S) in a corresponding molar ratio. Single phosphorus (P) and single sulfur (S) can be used without particular limitation as long as they are industrially produced and sold.

Lithium nitride may be used as a raw material. Here, since nitrogen in lithium nitride is discharged into the system as N ₂ , a sulfide-based inorganic solid containing Li, P, and S as constituent elements by using lithium nitride as an inorganic compound as a raw material It is possible to increase only the Li composition to the electrolyte material.
The lithium nitride according to this embodiment is not particularly limited, and commercially available lithium nitride (for example, Li ₃ N) may be used. For example, metallic lithium (for example, Li foil) and nitrogen gas may be used. Lithium nitride obtained by the reaction of From the viewpoint of obtaining a high purity solid electrolyte material and from the viewpoint of suppressing side reaction, it is preferable to use lithium nitride with few impurities.

In addition, the sulfide-based inorganic solid electrolyte material according to the present embodiment can be contained in the sulfide-based inorganic solid electrolyte material from the viewpoint of improving the electrochemical stability, the stability in water and air, the handleability, and the like. The molar ratio Li / P of the content of the Li to the content of the P is preferably 1.0 or more and 10.0 or less, more preferably 1.0 or more and 5.0 or less, and still more preferably 2. It is 0 or more and 4.0 or less, more preferably 2.5 or more and 3.5 or less, and particularly preferably 2.8 or more and 3.2 or less. Moreover, molar ratio S / P of content of said S with respect to content of said P becomes like this. Preferably it is 1.0 or more and 10.0 or less, More preferably, it is 2.0 or more and 6.0 or less, More preferably, It is 3.0 or more and 5.0 or less, still more preferably 3.5 or more and 4.5 or less, and particularly preferably 3.8 or more and 4.2 or less.
Here, the content of Li, P and S in the sulfide-based inorganic solid electrolyte material according to the present embodiment can be determined, for example, by ICP emission spectroscopy or X-ray photoelectron spectroscopy.

In addition, the sulfide-based inorganic solid electrolyte material according to the present embodiment is excellent in electrochemical stability, stability in water and air, handleability, and the like, and can further suppress the generation of hydrogen sulfide. From the viewpoint, the ortho composition Li ₃ PS ₄ is preferable.
Here, Li ₃ PS ₄ corresponds to the ortho composition in the Li ₂ S—P ₂ S ₅ based sulfide-based inorganic solid electrolyte material. In addition, since Li ₂ S theoretically does not remain in the sulfide-based inorganic solid electrolyte material having the ortho composition, generation of hydrogen sulfide derived from Li ₂ S can be further prevented.

As a shape of the inorganic solid electrolyte material which concerns on this embodiment, a particulate form can be mentioned, for example. The particulate inorganic solid electrolyte material of the present embodiment is not particularly limited, but the average particle diameter d ₅₀ in weight-based particle size distribution by laser diffraction / scattering type particle size distribution measurement method is preferably 1 μm to 50 μm, more preferably It is 2 micrometers or more and 40 micrometers or less, More preferably, they are 3 micrometers or more and 35 micrometers or less.
By setting the average particle diameter d ₅₀ of the inorganic solid electrolyte material in the above range, it is possible to maintain good handling properties and to further improve lithium ion conductivity of the obtained solid electrolyte membrane.

It does not specifically limit as said positive electrode active material, For example, the positive electrode active material which can be used for the positive electrode layer of a lithium ion battery is mentioned. For example, lithium cobalt oxide (LiCoO ₂ ), lithium nickel oxide (LiNiO ₂ ), lithium manganese oxide (LiMn ₂ O ₄ ), solid solution oxide (Li ₂ MnO ₃ -LiMO ₂ (M = Co, Ni, etc.) Complex oxides such as lithium-manganese-nickel oxide (LiNi _1/3 Mn _1/3 Co _1/3 O ₂ ), olivine type lithium phosphorus oxide (LiFePO ₄ ), etc .; CuS, Li-Cu-S compound Sulfide-based positive electrode active materials such as TiS ₂ , FeS, MoS ₂ , V ₂ S ₅ , Li-Mo-S compounds, Li-Ti-S compounds, Li-V-S compounds, Li-Fe-S compounds, etc. Can be mentioned.
Among these, from the viewpoint of having higher discharge capacity density and being excellent in cycle characteristics, a sulfide-based positive electrode active material is preferable, and a Li-Mo-S compound, a Li-Ti-S compound, a Li-V-S compound Compounds are more preferred.

Here, the Li-Mo-S compound contains Li, Mo, and S as constituent elements, and the inorganic composition containing molybdenum sulfide and lithium sulfide, which are the raw materials, is usually chemically treated with each other by mechanical processing. It can be obtained by reaction.
In addition, the Li-Ti-S compound contains Li, Ti, and S as constituent elements, and usually chemically reacts with each other by mechanical processing of an inorganic composition containing titanium sulfide and lithium sulfide as raw materials. It can be obtained by
The Li-V-S compound contains Li, V, and S as constituent elements, and usually chemically reacts with each other by mechanical processing an inorganic composition containing vanadium sulfide and lithium sulfide as raw materials. It can be obtained by

It does not specifically limit as said negative electrode active material, For example, the negative electrode active material which can be used for the negative electrode layer of a lithium ion battery is mentioned. For example, metal materials mainly composed of lithium alloy, tin alloy, silicon alloy, gallium alloy, indium alloy, aluminum alloy and the like; lithium titanium composite oxide (for example, Li ₄ Ti ₅ O ₁₂ ) and the like can be mentioned.

(Step of Forming Intermediate to Obtain Intermediate Inorganic Composition (A3))
Subsequently, by heating the raw material inorganic composition (A2) at a temperature lower than the crystallization temperature of the inorganic material (A), two or more kinds of inorganic compounds (A1) are reacted to produce an intermediate inorganic composition (A3). obtain. Here, when heating is performed at a temperature equal to or higher than the crystallization temperature of the inorganic material (A), the crystallization of the raw material inorganic composition (A2) proceeds to become a more stable state. As a result, the time of the vitrification process is significantly increased, which is not preferable.
The temperature when heating the raw material inorganic composition (A2) can be appropriately set according to the crystallization temperature of the target inorganic material (A).
Here, the crystallization temperature of the inorganic material (A) can be measured, for example, by differential thermal analysis. For example, when the temperature of the inorganic material (A) is slowly raised using a differential thermal analyzer, an endothermic peak appears at the glass transition temperature, and then an exothermic peak appears when the crystallization temperature is reached. The peak temperature can be measured and the peak temperature can be taken as the crystallization temperature.

  For example, when the target inorganic material (A) contains a sulfide-based inorganic solid electrolyte material, the raw material inorganic composition (from the viewpoint of effectively advancing the reaction while suppressing the thermal decomposition and the like of the raw material inorganic composition (A2) The heat treatment temperature of A2) is preferably in the range of 180 ° C. to less than 260 ° C., more preferably in the range of 200 ° C. to 255 ° C., and in the range of 220 ° C. to 250 ° C. Is more preferred.

  Although the time to heat a raw material inorganic composition (A2) is not specifically limited, For example, it exists in the range of 1 minute or more and 24 hours or less, Preferably it is 0.1 hours or more and 10 hours or less. Although the method of heating is not specifically limited, For example, the method of using a kiln can be mentioned. In addition, conditions, such as temperature at the time of such heating, time, can be suitably adjusted, in order to optimize the characteristic of the inorganic material (A) which concerns on this embodiment.

  In addition, whether or not two or more inorganic compounds (A1) react to obtain an intermediate inorganic composition (A3) is, for example, new in a spectrum obtained by X-ray diffraction using CuKα radiation as a radiation source. It can be judged whether or not a crystal peak is generated.

If the purpose of the inorganic material (A) is a sulfide-based inorganic solid electrolyte material, an intermediate inorganic composition (A3) preferably contains a _{Li 4 P 2 S 6, Li} 4 P 2 S 6 and _Li 3 PS ₄ It is more preferable to include Li ₄ P ₂ S ₆ , Li ₃ PS ₄ and Li ₂ S.
Here, for identification of the inorganic compound contained in the intermediate inorganic composition (A3), for example, the X-ray diffraction pattern of the intermediate inorganic composition (A3) is measured, and the obtained X-ray diffraction pattern, JCPDS (Joint Committee It can be identified by comparing known XRD data bases such as on Powder Diffraction Standards) cards.

(Vitrification process to obtain inorganic material (A))
Subsequently, the resulting intermediate inorganic composition (A3) is mechanically treated to react the intermediate inorganic composition (A3) and to vitrify to obtain an inorganic material (A).
Here, the mechanical treatment can vitrify the chemical reaction of the intermediate inorganic composition (A3) by causing the inorganic compounds constituting the intermediate inorganic composition (A3) to mechanically collide with each other. For example, mechanochemical processing etc. are mentioned.

  Here, the mechanochemical treatment is a method of vitrifying while applying mechanical energy such as shear force, impact force or centrifugal force to the target composition. The apparatus for performing vitrification by mechanochemical treatment includes grinding and dispersing machines such as ball mill, bead mill, vibration mill, turbo mill, mechano fusion, disc mill, roll mill, etc .; rotary machines represented by rock drilling machine, vibration drill, impact driver etc. A rotary / impact pulverizer comprising a mechanism combining (shear stress) and impact (compressive stress); high pressure type gliding rolls etc. may be mentioned. Among these, a ball mill and a bead mill are preferable, and a ball mill is particularly preferable, from the viewpoint of being able to efficiently generate very high impact energy. In addition, from the viewpoint of excellent continuous productivity, a roll mill; a rotary / impact pulverizer comprising a mechanism combining rotation (shear stress) and impact (compressive stress) represented by a rock drilling machine, vibration drill, impact driver, etc. High pressure type gliding rolls are preferred.

In addition, the mechanochemical treatment is preferably performed in a non-active atmosphere. Thereby, the reaction of the intermediate inorganic composition (A3) or the inorganic material (A) with water vapor or oxygen can be suppressed.
Moreover, under the said inactive atmosphere is under vacuum atmosphere or inert gas atmosphere. Under the non-active atmosphere, the dew point is preferably −50 ° C. or less, more preferably −60 ° C. or less, in order to avoid contact with water. The inert gas atmosphere is an atmosphere of an inert gas such as argon gas, helium gas, nitrogen gas and the like. These inert gases are preferably as high in purity as possible to prevent contamination of the product with impurities. The method of introducing the inert gas into the mixed system is not particularly limited as long as the mixed system is filled with an inert gas atmosphere, but a method of purging the inert gas, the constant amount of the inert gas is continued to be introduced Methods etc.

  In addition, when the intermediate inorganic composition (A3) is vitrified, an aprotic organic solvent such as hexane, toluene or xylene may be added to vitrify the respective raw materials dispersed in the solvent.

The mixing conditions such as the rotational speed, processing time, temperature, reaction pressure, and gravity acceleration applied to the intermediate inorganic composition (A3) when vitrifying the intermediate inorganic composition (A3) are the kind and throughput of the inorganic composition. It can be determined as appropriate. Generally, the higher the rotational speed, the faster the rate of glass formation, and the longer the treatment time, the higher the conversion to glass.
Usually, when X-ray diffraction analysis is performed using CuKα radiation as a radiation source, the intermediate inorganic composition (A3) is vitrified if the diffraction peak of the intermediate inorganic composition (A3) disappears or decreases. It can be determined that the inorganic material (A) is obtained.

Here, when the target inorganic material (A) is a sulfide-based inorganic solid electrolyte material, it can be obtained by X-ray diffraction using CuKα rays as a radiation source in the step of vitrifying the intermediate inorganic composition (A3) the maximum diffraction intensity at the position of the diffraction angle 2θ = 15.7 ± 0.3 ° in the spectrum by the background intensity _{I a,} the diffraction peak at the position of the diffraction angle 2θ = 26.9 ± 0.9 ° The mechanical processing is preferably performed until the value of I _B / I _A is preferably 12.2 or less, more preferably 12.0 or less, when the diffraction intensity is I _B.
By setting I _B / I _A to the above upper limit value or less, lithium ion conductivity of the sulfide-based inorganic solid electrolyte material can be improved. Furthermore, when such a sulfide-based inorganic solid electrolyte material is used, an all-solid-state lithium ion battery excellent in input / output characteristics can be obtained.
Here, the maximum diffraction intensity existing at the position of the diffraction angle 2θ = 15.7 ± 0.3 ° is the reference diffraction intensity, and the diffraction angle existing at the position of the diffraction angle 2θ = 26.9 ± 0.9 ° The peaks are diffraction peaks derived from lithium sulfide.
Therefore, I _B / I _A represents an index of the content of lithium sulfide in the sulfide-based inorganic solid electrolyte material. The smaller I _B / I _A means that the amount of lithium sulfide contained in the sulfide-based inorganic solid electrolyte material is smaller.
Since lithium sulfide has low lithium ion conductivity, it is considered that lithium ion conductivity of the sulfide-based inorganic solid electrolyte material improves as the content of lithium sulfide decreases.

When the target inorganic material (A) is a sulfide-based inorganic solid electrolyte material, in the step of vitrifying the intermediate inorganic composition (A3), 27.0 ° C., applied voltage 10 mV, measurement frequency range 0.1 Hz Mechanical treatment until lithium ion conductivity by AC impedance method under measurement conditions of ~ 7 MHz becomes 0.5 10 ⁴ S cm ^-1 or more, preferably 1.0 10 ⁴ S cm ¹ or more It is preferable to Thus, a sulfide-based inorganic solid electrolyte material can be obtained which is further excellent in lithium ion conductivity.

(Crystallization step of crystallizing at least a part of the inorganic material (A))
Subsequently, after the vitrification process, the obtained inorganic material (A) may be heated to further perform a crystallization process of crystallizing at least a part of the inorganic material (A). By heating the obtained inorganic material (A) in the glass state, at least a part of the inorganic material (A) is crystallized to obtain the inorganic material (A) in the glass ceramic state (also called crystallized glass). be able to. By doing this, it is possible to obtain, for example, an inorganic solid electrolyte material having even more excellent lithium ion conductivity.

The temperature at which the glassy inorganic material (A) is heated is not particularly limited as long as crystallization can be sufficiently advanced. For example, while suppressing the thermal decomposition of the inorganic material (A) It is preferable to be in the range of 260 ° C. or more and 500 ° C. or less, more preferably in the range of 270 ° C. or more and 350 ° C. or less, and in the range of 280 ° C. or more and 350 ° C. or less. It is further preferred that
The time for heating the glassy inorganic material (A) is not particularly limited as long as the desired inorganic material (A) can be obtained, but is, for example, in the range of 1 minute to 24 hours. Preferably, they are 0.5 hours or more and 3 hours or less. Although the method of heating is not specifically limited, For example, the method of using a kiln can be mentioned. In addition, conditions, such as temperature at the time of such heating, time, can be suitably adjusted, in order to optimize the characteristic of an inorganic material (A).

Moreover, it is preferable to perform heating of the inorganic material (A) of a glass state, for example under inert gas atmosphere. Thereby, deterioration (for example, oxidation) of the inorganic material (A) can be prevented.
As an inert gas at the time of heating the inorganic material (A) of a glass state, argon gas, helium gas, nitrogen gas etc. are mentioned, for example. These inert gases are preferably as high in purity as possible to prevent the contamination of impurities into the product, and preferably have a dew point of −50 ° C. or less to avoid contact with moisture, −60 It is particularly preferable that the temperature is not higher than ° C. The method of introducing the inert gas into the mixed system is not particularly limited as long as the mixed system is filled with an inert gas atmosphere, but a method of purging the inert gas, the constant amount of the inert gas is continued to be introduced Methods etc.

(Step of crushing, classification or granulation)
In the method of producing the inorganic material (A) according to the present embodiment, the step of pulverizing, classifying, or granulating the obtained inorganic material (A) may be further performed, as necessary. For example, it is possible to obtain an inorganic material (A) having a desired particle size by pulverizing it into fine particles and then adjusting the particle size by classification operation or granulation operation. The above-mentioned pulverizing method is not particularly limited, and a known pulverizing method such as a mixer, pneumatic pulverizing, a mortar, a rotary mill, a coffee mill or the like can be used. Moreover, it does not specifically limit as said classification method, Well-known methods, such as a sieve, can be used.
It is preferable to carry out such pulverization or classification under an inert gas atmosphere or a vacuum atmosphere in that it can prevent contact with moisture in the air.

As mentioned above, although embodiment of this invention was described, these are the illustrations of this invention, and various structures other than the above can also be employ | adopted.
Note that the present invention is not limited to the above-described embodiment, and modifications, improvements, and the like as long as the object of the present invention can be achieved are included in the present invention.

  Hereinafter, the present invention will be described by way of Examples and Comparative Examples, but the present invention is not limited thereto.

<Evaluation method>
First, evaluation methods in the following examples and comparative examples will be described.

(1) X-ray Diffraction Analysis Diffraction spectra of the sulfide-based inorganic solid electrolyte materials obtained in Examples and Comparative Examples were each obtained by X-ray diffraction analysis using an X-ray diffractometer (RINT 2000, manufactured by Rigaku Corporation) I asked. In addition, CuK alpha ray was used as a radiation source. Here, the diffraction peak of maximum diffraction intensity at the position of the diffraction angle 2θ = 15.7 ± 0.3 ° and background intensity _{I A,} at the position of the diffraction angle 2θ = 26.9 ± 0.9 ° I _B / I _A was determined by setting I _{B as} the diffraction intensity of The obtained results are shown in Tables 1 to 4.

(2) Measurement of Lithium Ion Conductivity The lithium ion conductivity of the sulfide-based inorganic solid electrolyte material obtained in Examples and Comparative Examples was measured by an AC impedance method.
The measurement of lithium ion conductivity used the biologic company make and potentiostat / galvanostat SP-300. The sample had a diameter of 9.5 mm, a thickness of about 1.3 mm, measurement conditions were an applied voltage of 10 mV, a measurement temperature of 27.0 ° C., a measurement frequency range of 0.1 Hz to 7 MHz, and an electrode of Li foil.
Here, as a sample for lithium ion conductivity measurement, it can be obtained by pressing 150 mg of the powdery sulfide-based inorganic solid electrolyte material obtained in Examples and Comparative Examples at 270 MPa for 10 minutes using a press device. A plate-like sulfide-based inorganic solid electrolyte material having a diameter of 9.5 mm and a thickness of about 1.3 mm was used.

Example 1
The Li 2 _{S-P 2} S ₅ material is a sulfide-based inorganic solid electrolyte material was prepared by the following procedure.
As raw materials, Li ₂ S (manufactured by Sigma Aldrich Japan, purity 99.9%) and P ₂ S ₅ (reagent manufactured by Kanto Chemical Co., Ltd.) were used.
A total of 30 g of Li ₂ S powder and P ₂ S ₅ powder (Li ₂ S: P ₂ S ₅ = 80: 20 (mol%)) was mixed in a ball mill (400 mL pot, using 10 g ball of φ 10 mm) at 120 rpm for 1 hour .
Subsequently, 5.0 g of the obtained mixture (raw material inorganic composition) is put in an alumina crucible, and heated at 240 ° C. for 1 hour in a heating furnace in a glove box to react Li ₂ S and P ₂ S ₅ to obtain an intermediate inorganic The composition was obtained.
Next, 2.5 g of the obtained intermediate inorganic composition was mechanochemically treated with a ball mill (400 mL pot, using 10 g balls 500 g) at 120 rpm for 200 hours to obtain a sulfide-based inorganic solid electrolyte material.
Here, sampling was performed every 100 hours, and X-ray diffraction analysis and measurement of lithium ion conductivity were performed.
Moreover, the crystallization temperature of the obtained sulfide type inorganic solid electrolyte material was 265 degreeC. Note that 4.5 mg of the sulfide-based inorganic solid electrolyte material was heated from room temperature to 450 ° C. at a rate of 10 ° C./min in an environment where high purity argon gas was introduced at 400 ml / min using a differential thermal analyzer. The peak temperature of the obtained exothermic peak was measured, and the peak temperature was taken as the crystallization temperature.
The obtained results are shown in FIGS.

Examples 2 to 4 and Comparative Example 1
A sulfide-based inorganic solid electrolyte material was prepared in the same manner as in Example 1 except that the heating time in the heating furnace was changed as shown in Table 1, and each evaluation was performed on the obtained sulfide-based inorganic solid electrolyte material. The The obtained results are shown in FIGS.

Examples 5 to 8
A sulfide-based inorganic solid electrolyte material was prepared in the same manner as in Example 1 except that the time of mechanochemical treatment was changed as shown in Table 2, and each of the obtained sulfide-based inorganic solid electrolyte materials was evaluated. . The obtained results are shown in FIG. 4 and Table 2.

Examples 9 and 10
The Li 2 _{S-P 2} S ₅ material is a sulfide-based inorganic solid electrolyte material was prepared by the following procedure.
As raw materials, Li ₂ S (manufactured by Sigma Aldrich Japan, purity 99.9%) and P ₂ S ₅ (reagent manufactured by Kanto Chemical Co., Ltd.) were used.
A total of 30 g of Li ₂ S powder and P ₂ S ₅ powder (Li ₂ S: P ₂ S ₅ = 75: 25 (mol%)) were mixed in a ball mill (400 mL pot, using 10 g ball of φ10 mm) at 120 rpm for 1 hour .
Subsequently, 5.0 g of the obtained mixture (raw material inorganic composition) is put in an alumina crucible, and heated at 240 ° C. for 1 hour in a heating furnace in a glove box to react Li ₂ S and P ₂ S ₅ to obtain an intermediate inorganic The composition was obtained.
Here, two methods were implemented for heating the raw material inorganic composition.
(A) The raw material inorganic composition was put into an alumina crucible as it was in powder form and heated (Example 9).
(B) The raw material inorganic composition was compacted (diameter 25 mm, 89 MPa, 10 minutes), placed in an alumina crucible and heated (Example 10).
Next, 2.5 g of the intermediate inorganic composition obtained in (a) and (b) is mechanochemically treated at 120 rpm for 200 hours in a ball mill (400 mL pot, using φ 10 mm ball 500 g) for 200 hours to obtain a sulfide inorganic solid electrolyte material I got each. However, for the intermediate inorganic composition obtained in (b), the green compact was crushed in a mortar and then placed in a ball mill.
Here, sampling was performed every six hours, and X-ray diffraction analysis and measurement of lithium ion conductivity were performed.
Moreover, the crystallization temperature of the obtained sulfide type inorganic solid electrolyte material was 260 degreeC. Note that 4.5 mg of the sulfide-based inorganic solid electrolyte material was heated from room temperature to 450 ° C. at a rate of 10 ° C./min in an environment where high purity argon gas was introduced at 400 ml / min using a differential thermal analyzer. The peak temperature of the obtained exothermic peak was measured, and the peak temperature was taken as the crystallization temperature.
The obtained results are shown in FIG. 5 and Table 3.

Comparative Example 1
A sulfide-based inorganic solid electrolyte material was produced in the same manner as in Example 9 except that the mixture (raw material inorganic composition) was not heated and the raw material inorganic composition was treated by mechanochemical treatment as it is, and the obtained sulfide-based inorganic solid material was obtained. Each evaluation was performed about solid electrolyte material. The obtained results are shown in FIG. 6 and Table 4.

It was found from FIG. 1 that a new crystal peak was generated by heating the raw material inorganic composition (Li ₂ S: P ₂ S ₅ = 80: 20 (mol%)). That is, by heating the raw inorganic composition, Li ₂ S and P ₂ S ₅ react to form an intermediate inorganic composition containing Li ₄ P ₂ S ₆ , Li ₃ PS ₄ and Li ₂ S That was confirmed.
Moreover, it turned out that a crystal | crystallization peak lose | disappears or declines by carrying out a mechanochemical process of the intermediate | middle inorganic composition from FIG. 2 and 3. FIG. That is, it could be confirmed that the intermediate inorganic composition could be vitrified. Here, according to FIG. 2, in Examples 1 to 4 in which the intermediate inorganic composition was formed and then vitrified, crystals were obtained in a shorter time than in Comparative Example 1 in which the intermediate inorganic composition was not generated. It can be understood that vitrification can be performed in a shorter time since the peak is eliminated or reduced. This can also be understood from the lithium ion conductivity in Table 1.
Moreover, according to the manufacturing method of the inorganic material which concerns on this embodiment which performs an intermediate formation process before a vitrification process from FIG. 4 and Table 2, even visceral mechanochemical processing for 6 hours is fully vitrified, and lithium ion is high. It can be seen that the conductivity can be realized.
On the other hand, Table 1 shows that 200 hours of mechanochemical treatment is required to obtain sufficiently high lithium ion conductivity when the intermediate formation step is not performed before the vitrification step as in Comparative Example 1 Recognize.

It was found from FIG. 5 that a new crystal peak was generated by heating the raw material inorganic composition (Li ₂ S: P ₂ S ₅ = 75: 25 (mol%)). That is, by heating the raw inorganic composition, Li ₂ S and P ₂ S ₅ react to form an intermediate inorganic composition containing Li ₄ P ₂ S ₆ , Li ₃ PS ₄ and Li ₂ S That was confirmed.
In addition, it is understood from FIG. 5 that the mechanochemical treatment of the intermediate inorganic composition causes the crystal peak to disappear or decrease. That is, it could be confirmed that the intermediate inorganic composition could be vitrified. Here, from FIGS. 5 and 6, Examples 9 and 10 in which the intermediate inorganic composition was formed and then vitrified were shorter in time than in Comparative Example 2 in which the intermediate inorganic composition was not generated. It can be understood that vitrification can be achieved in a shorter time, since the crystal peak has disappeared or decreased. This can also be understood from the lithium ion conductivity in Tables 3 and 4.

(Reference example)
The purpose of the inorganic material (A) _{is, Li 9.3 P 3 S 12 (} 27Li 2 S-9P 2 S 5 -0.6Li 3 N), Li 9.6 P 3 S 12 (27Li 2 S-9P 2 S ₅ -1.2Li ₃ N) and _Li 10 _P 3 for the case where a _{S 12 (27Li 2 S-9P} 2 S 5 -2Li 3 N), 1 hour heating each raw material inorganic composition (A2) at 220 ° C., respectively It was confirmed by X-ray diffraction analysis that an intermediate inorganic composition (A3) containing Li ₂ S, Li ₄ P ₂ S ₆ , and Li ₃ PS ₄ was formed when the reaction was conducted (see FIG. 7).

  As mentioned above, according to the manufacturing method of the inorganic material which concerns on this embodiment, it can be understood that vitrification of an inorganic composition can be performed in a short time, and it is possible to shorten manufacturing time.

Claims (14)

It is a manufacturing method for manufacturing an inorganic material (A) obtained by two or more kinds of inorganic compounds (A1),
A step of preparing a raw material inorganic composition (A2) containing the two or more types of inorganic compounds (A1);
By heating the raw material inorganic composition (A2) at a temperature lower than the crystallization temperature of the inorganic material (A), the two or more kinds of inorganic compounds (A1) are reacted to produce an intermediate inorganic composition (A3). Obtaining intermediates,
Vitrifying the obtained intermediate inorganic composition (A3) by mechanical treatment to cause the intermediate inorganic composition (A3) to react and vitrify to obtain the inorganic material (A);
A method of producing an inorganic material comprising In the method of producing an inorganic material according to claim 1,
The method of manufacturing an inorganic material, wherein the mechanical treatment includes mechanochemical treatment. In the method of producing an inorganic material according to claim 1 or 2,
The manufacturing method of the inorganic material whose said inorganic material (A) is an inorganic solid electrolyte material, a positive electrode active material, or a negative electrode active material. In the method of producing an inorganic material according to claim 1 or 2,
The manufacturing method of the inorganic material in which the said inorganic material (A) contains a sulfide type inorganic solid electrolyte material. In the method of producing an inorganic material according to claim 4,
The method for producing an inorganic material wherein the sulfide-based inorganic solid electrolyte material has lithium ion conductivity and contains Li, P and S as constituent elements. In the method of producing an inorganic material according to claim 4 or 5,
The manufacturing method of the inorganic material in which said 2 or more types of inorganic compounds (A1) contain lithium sulfide and phosphorus sulfide at least. In the method for producing an inorganic material according to claim 5 or 6,
The molar ratio Li / P of the content of the Li to the content of the P in the sulfide-based inorganic solid electrolyte material is 1.0 or more and 10.0 or less, and the content of the S relative to the content of the P The manufacturing method of the inorganic material which is molar ratio S / P of 1.0 or more and 10.0 or less. In the method for producing an inorganic material according to claim 5 or 6,
Method of producing an inorganic material the sulfide-based inorganic solid electrolyte material comprises Li ₃ PS _4. A method of producing an inorganic material according to any one of claims 4 to 8,
Production method of the inorganic material intermediate inorganic composition (A3) contains a _Li 4 _P 2 _{S 6.} In the method of producing an inorganic material according to any one of claims 4 to 9,
The manufacturing method of the inorganic material whose heat processing temperature of the said raw material inorganic composition (A2) in the said intermediate | middle production | generation process is 180 degreeC or more and less than 260 degreeC. A method of producing an inorganic material according to any one of claims 4 to 10,
The manufacturing method of the inorganic material which is an inorganic solid electrolyte material in which the said sulfide type inorganic solid electrolyte material is used for the solid electrolyte layer which comprises an all-solid-type lithium ion battery. In the method for producing an inorganic material according to any one of claims 4 to 11,
In the vitrification process,
Maximum diffraction intensity and background intensity I _A, a diffraction angle 2 [Theta] = 26 at the position of the diffraction angle 2θ = 15.7 ± 0.3 ° in the spectrum obtained by X-ray diffraction using a CuKα ray as a radiation source. 9 when the diffraction intensity of the diffraction peak at the position of ± 0.9 ° was I _B, the production method of the inorganic material to perform the mechanical processing until the value of I B _/ I _a is 12.2 or less. A method of producing an inorganic material according to any one of claims 4 to 12,
In the vitrification process,
The lithium ion conductivity of the inorganic material (A) is 0.5 × 10 ⁻⁴ S · cm ⁻¹ by an alternating current impedance method under measurement conditions of 27.0 ° C., an applied voltage of 10 mV and a measurement frequency range of 0.1 Hz to 7 MHz. The manufacturing method of the inorganic material which performs the said mechanical processing until it becomes above. In the method for producing an inorganic material according to any one of claims 1 to 13,
The manufacturing method of the inorganic material which further includes the crystallization process which crystallizes at least one part of the said inorganic material (A) by heating the obtained said inorganic material (A) after the said vitrification process.

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