JP5806621B2 - Solid electrolyte glass and lithium ion battery using the same - Google Patents

Description

  The present invention relates to a solid electrolyte glass, glass ceramic, a positive electrode using the same, and a lithium ion battery.

In recent years, development of lithium ion batteries with high safety and high capacity has been actively conducted.
Lithium ion batteries currently in practical use have the drawback of low safety because the electrolyte is liquid. Therefore, an inorganic solid electrolyte has been developed (see, for example, Patent Document 1).

  Among solid electrolytes, sulfide-based solid electrolytes are actively studied because they have high ionic conductivity. One of the problems with sulfide-based solid electrolytes is that hydrogen sulfide gas is generated by moisture contact. Therefore, safety measures are required.

  In order to suppress the generation of hydrogen sulfide gas, Patent Document 2 discloses a sulfide-based solid electrolyte that does not contain bridging sulfur and lithium sulfide. However, since the material of the sulfide-based solid electrolyte is lithium sulfide, it is necessary to completely react the raw materials. Therefore, the manufacturing cost is very high because a long-time mechanical milling process is required.

Japanese Patent Laid-Open No. 11-134937 JP 2010-199033 A

  An object of the present invention is to provide a solid electrolyte (glass or glass ceramic) in which generation of hydrogen sulfide gas due to moisture contact is suppressed.

The present inventors have found that even if lithium sulfide is present in the solid electrolyte, it may not necessarily be a source for generating hydrogen sulfide gas.
Conventionally, it has been necessary to increase the reaction time (treatment time) so that lithium sulfide as a raw material does not remain in the solid electrolyte. However, in the present invention, since lithium sulfide may remain, the reaction time is reduced. A shortened manufacturing method can be employed.

According to the present invention, the following glasses and the like are provided.
1. A glass containing lithium element (Li) and sulfur element (S),
The glass containing lithium sulfide, and the residual ratio of the lithium sulfide by X-ray diffraction analysis is 30% or less.
2. A glass containing lithium element (Li), phosphorus element (P) and sulfur element (S), wherein the Raman spectrum of the glass is measured five times or more, and a peak at 330 to 450 cm ^{−1 in} the Raman spectrum is separated into waveforms. The standard deviation of the area ratio separated into each component is 3.0 or less, and the PS ₄ ^3- component peak area obtained by waveform separation is 10 to 95% of the total, The area of the peak of the same P ₂ S ₇ ^4- component is 5 to 45% of the whole, and the area of the peak of the PS ₄ ^3- component is wider than the area of the peak of the P ₂ S ₇ ^4- component. The glass contains a solvent, the residual amount of the solvent is 5% by mass or less, and the ionic conductivity is 1.0 × 10 ⁻⁴ S / cm or more.
3. The glass according to 1, which contains a solvent after heat drying at 150 ° C. for 2 hours, and the residual amount of the solvent is 5% by mass or less.
4). Glass in any one of 1-3 whose average particle diameter is 20 micrometers or less and whose content rate of the particle | grains whose particle diameter is 50 micrometers or more is 3 mass% or less.
5. Glass in any one of 1-4 obtained by making a raw material react in an organic solvent.
6). 6. The glass according to 5, wherein the raw material contains atomized lithium sulfide.
7). 7. The glass according to 6, wherein the atomized lithium sulfide has a surface area of 1 m ² / g or more.
8). The glass ceramic obtained by heat-processing the glass in any one of said 1-7.
9. A positive electrode comprising at least one of the glass according to any one of 1 to 7 and the glass ceramic according to 8.
10. A lithium ion battery provided with the layer containing at least one of the glass in any one of said 1-7, and the glass ceramic of 8.

ADVANTAGE OF THE INVENTION According to this invention, the sulfide type solid electrolyte which suppressed generation | occurrence | production of the hydrogen sulfide gas by moisture contact can be provided.
Since the solid electrolyte of the present invention can be produced by a production method by a slurry method using a solvent, it is not necessary to employ a production method with high energy consumption such as a mechanical milling method. Therefore, the manufacturing cost of the solid electrolyte can be reduced.

It is an example of a Raman spectrum. This is an example in which a Raman spectrum is separated into each peak using waveform separation software. It is a figure which shows one Embodiment of the manufacturing apparatus of the glass of this invention. It is a figure which shows other embodiment of the manufacturing apparatus of the glass of this invention. 2 is a particle size distribution of the solid electrolyte glass produced in Example 1. 2 is an X-ray diffraction spectrum of the solid electrolyte glass produced in Comparative Example 1. FIG.

1. 1st aspect of the glass of this invention The 1st aspect of the glass of this invention is glass (solid electrolyte) containing a lithium element (Li) and a sulfur element (S). The glass contains lithium sulfide, and the residual ratio of lithium sulfide by XRD analysis is 30% or less. When the residual ratio of lithium sulfide exceeds 30%, the amount of hydrogen sulfide generated increases. Moreover, lithium ion conductivity falls.
The residual ratio of lithium sulfide is preferably 15% or less. The lower the rate of remaining lithium sulfide, the more preferable it is from the viewpoint of suppressing the amount of hydrogen sulfide generated, but it is preferably 0.1% or more, more preferably 1% or more in view of the production time. More preferably, it is 2% or more.

The residual rate of lithium sulfide is determined by relatively quantifying from the X-ray diffraction (XRD) spectrum of the glass. Specifically, for example, when lithium sulfide and phosphorus sulfide are used as raw materials, the lithium sulfide-phosphorus sulfide mixture before the reaction has the strongest peak intensity around 2θ = 27 °. By reacting, this peak intensity decreases. In the present application, baseline correction is performed, and the residual ratio is determined from the ratio of peak heights.
In addition, since the intensity | strength of a XRD spectrum changes with measuring instruments, the conditions at the time of a measurement, etc., it is necessary to measure the lithium sulfide-phosphorus sulfide mixture (standard sample) before reaction every time.
Moreover, since glass is easily affected by moisture, it is necessary to prepare a measurement sample by sealing it under an inert gas.

  In the glass of this embodiment, it is preferable that the solvent is contained after the heat drying treatment at 150 ° C. for 2 hours, and the residual amount of the solvent is 5% by mass or less. Here, it is preferable that the residual amount of the solvent is small, but from the viewpoint of reducing the heat drying temperature and shortening the heat drying time, the lower limit of the residual amount may be 0.2% by mass or more, 0.5 mass% or more may be sufficient, and also 1 mass% or more may be sufficient.

If the glass contains a solvent even after sufficient drying by heating, it means that the solvent was used during the production of the glass. When a solvent is used during production, the solvent remains slightly even after the drying step. On the other hand, when the sufficiently dried glass does not detect the solvent, it can be presumed that the glass was obtained by a solvent-free process. Specifically, after removing the solvent, the solvent remains in the glass even when dried at 150 ° C. for 2 hours under vacuum. Even if a solvent is added to a glass produced by a solvent-free production method, the glass is immersed in a solvent, or mixed, when the solvent is dried by heating as described above, the solvent does not fly and no solvent is detected.
The amount of solvent is determined by gas chromatography after dissolving glass in methanol to make a homogeneous solution.

2. Second Aspect of Glass of the Present Invention A second aspect of the glass of the present invention is a glass containing lithium element (Li), phosphorus element (P) and sulfur element (S). And the Raman spectrum of glass is measured 5 times or more, the peak of 330-450 cm < ^-1 > in this Raman spectrum is waveform-separated, and the standard deviation of the area ratio isolate | separated into each component is all 3.0 or less. Moreover, the area of the peak of PS ₄ ^3- component obtained by waveform separation is 10 to 95% of the whole, and the area of the peak of the same P ₂ S ₇ ^4- component is 5 to 45% of the whole. , PS ₄ ^3- component peak area is wider than P ₂ S ₇ ^4- component peak area.
Further, the glass contains a solvent, the residual amount of the solvent is 5% by mass or less, and the ionic conductivity is 1.0 × 10 ⁻⁴ S / cm or more.

In the glass of this embodiment, the Raman spectrum is measured five times or more per sample, the peaks of 330 to 450 cm ⁻¹ in the Raman spectrum are separated into waveforms, and the standard deviation of the area ratio separated into each component is 3.0 or less in all cases. The area of the peak of PS ₄ ^3- component obtained by waveform separation is 10 to 95% of the whole, and the area of the peak of P ₂ S ₇ ^4- component is 5 to 45% of the whole. Yes, the PS ₄ ^3- component peak area is larger than the P ₂ S ₇ ^4- component peak area.

  The Raman spectrum is used to grasp the state of a solid, powder, etc., and is used as a numerical value for defining the properties of the solid material by grasping the characteristics of the spectrum (Japanese Patent Laid-Open No. 2005-336000, JP-A-10-326611, JP-A-2001-19450).

The Raman spectrum is suitable for analyzing the surface state of a solid. Even if particles of the same lot are measured, different spectra can be obtained if the composition of the particle surface is inhomogeneous.
For example, when mechanically milling a solid material, if a sufficiently pulverized part and a part adhering to the wall part and insufficiently pulverized are mixed, the homogeneity of the particles decreases, and the spectrum changes. As a result, when the measurement is repeated, the reproducibility of the spectrum decreases. Therefore, the surface state of the measurement particle can be evaluated by comparing the spectrum of the measurement particle with the reference based on the spectrum of the homogeneous material. In the present invention, the surface condition of the particles is evaluated using the spectral reproducibility, particularly the dispersion value as an index.

FIG. 1 shows an example of a Raman spectrum.
In the glass particles of the present invention, a characteristic peak is detected in the vicinity of 400 cm ⁻¹ . Since this peak is asymmetric, it is a mixed peak of a plurality of components. This peak has been identified as a mixed peak of PS ₄ ³⁻ , P ₂ S ₇ ⁴⁻ and P ₂ S ₆ ⁴⁻ (M. Tachez, J.-P. Malugani, R. Mercier, and G Robert, Solid State Ionics, 14, 181 (1984)).

It is desirable to detect the above-mentioned peaks for each component using a high-resolution device. However, even if peak separation is insufficient, the peak can be separated into individual peaks using general or device-specific waveform analysis software. Is possible. As the waveform analysis software, for example, GRAMS AI manufactured by Thermo SCIENTIFIC can be used.
FIG. 2 shows an example in which waveform separation software is used to separate each peak. From the separated peaks, the area value of each component can be obtained.
The standard deviation can be calculated from the above area value using a general calculation method. The measurement is desirably performed five times (five places) or more for one measurement target (particle aggregate). In addition, the same location of 1 measurement object is not measured repeatedly, but the location where a measurement object differs is measured 5 times or more.

In the present invention, when the standard deviation of the area ratio of each component (PS ₄ ^3- , P ₂ S ₇ ^4- and P ₂ S ₆ ^4- ) is 3.0 or less, the surface of each glass particle is homogeneous, Battery performance is stabilized when used in batteries. The standard deviations are preferably 2.7 or less, more preferably 2.5 or less, and particularly preferably 2.0 or less.

In the present invention, the PS ₄ ^3- component peak area obtained by waveform separation is 10 to 95% of the whole, and the P ₂ S ₇ ^4- component peak area is 5 to 45% of the whole. And the PS ₄ ^3- component peak area is wider than the P ₂ S ₇ ^4- component peak area. Thereby, a stable electrolyte is obtained.

Moreover, the glass of this aspect contains a solvent and the residual amount of a solvent is 5 mass% or less.
The lower limit of the residual amount is 0.2% by mass or more, may be 0.5% by mass or more, and may be 1% by mass or more.
The amount of solvent is determined by gas chromatography after dissolving glass in methanol to make a homogeneous solution.

Furthermore, the ionic conductivity of the glass is 1.0 × 10 ⁻⁴ S / cm or more. Thus, the glass of this aspect shows high ionic conductivity.
The ion conductivity is measured by the AC impedance method.

  In the glass of this embodiment, it is preferable that the glass contains lithium sulfide, and the residual ratio of lithium sulfide by XRD analysis is 30% or less. When the residual ratio of lithium sulfide exceeds 30%, the amount of hydrogen sulfide generated increases. Moreover, lithium ion conductivity falls. The residual ratio of lithium sulfide is preferably 15% or less. The lower the rate of remaining lithium sulfide, the more preferable it is from the viewpoint of suppressing the amount of hydrogen sulfide generated, but it is preferably 0.1% or more, more preferably 1% or more in view of the production time. More preferably, it is 2% or more.

About the glass which concerns on the 1st aspect and 2nd aspect mentioned above, it is preferable that an average particle diameter is 20 micrometers or less. More preferably, they are 0.10 micrometer or more and 15 micrometers or less, More preferably, they are 0.15 micrometers or more and 12 micrometers or less.
When the average particle size is larger than 20 μm, it may be difficult to make a thin film such as an electrolyte layer when manufacturing a battery.
In addition, when coarse particles are present, the thickness of the electrolyte layer is affected when a battery is manufactured, and the risk of a short circuit is increased. Therefore, the content of the solid electrolyte having a particle size of 50 μm or more is preferably 3% by mass or less. Especially preferably, it is 1 mass% or less.
In addition, the average particle diameter of glass means the volume reference | standard average particle diameter (MeanVolumeDiameter) measured with the laser diffraction type particle size distribution measuring apparatus. The particle size is preferably measured directly in the slurry state without passing through the dry state. Once dried, the particles may agglomerate during drying, resulting in an apparent increase in particle size.

Hereafter, the manufacturing method of the glass of this invention is demonstrated.
The raw material is not particularly limited, but lithium sulfide (Li ₂ S) and diphosphorus pentasulfide (P ₂ S ₅ ), or lithium sulfide and simple phosphorus and simple sulfur, as well as lithium sulfide, diphosphorus pentasulfide, simple phosphorus And / or elemental sulfur is preferred.
The ratio of Li element to P element (Li: P, molar ratio) in the raw material mixture preferably satisfies the following formula.
60:40 <Li: P ≦ 85: 15 (molar ratio)
If the above ratio is not satisfied, the ionic conductivity of the glass is lowered, which is not preferable.
Preferably, Li element is 70 to 83 mol%, P element is 17 to 30 mol%, and more preferably, Li element is 74 to 81 mol%, and P element is 19 to 26 mol%.

The molar ratio of Li, P and S elements in the glass can be adjusted by the element ratio of the raw materials. The element ratio of the raw material and the element ratio of the glass are almost the same.
The glass of the present invention may consist only of the above-described Li, P and S, and may contain a substance containing Al, B, Si, Ge or the like in addition to these elements.

Hereinafter, an example using lithium sulfide (Li ₂ S) and diphosphorus pentasulfide (P ₂ S ₅ ) as raw materials will be described.
As lithium sulfide, those commercially available without particular limitation can be used, but those having high purity are preferred.
Preferably, the lithium sulfide has a total content of lithium salts of sulfur oxides of 3.0% by mass or less, more preferably 2.5% by mass or less, and a content of lithium N-methylaminobutyrate of 0.1%. 15% by mass or less, more preferably 0.1% by mass or less, lithium hydroxide content is 4.0% by mass or less, more preferably 3.0% by mass or less, and lithium carbonate content is 2.0% by mass. % Or less, more preferably 1.0% by mass or less, lithium hydrosulfide content is 2.0% by mass or less, more preferably 1.0% by mass or less, metals other than lithium, sodium, potassium, magnesium, iron, etc. The total content of is 1.0% by mass or less, more preferably 0.1% by mass or less.
The purity of lithium sulfide is measured by potentiometric titration.

The method for producing lithium sulfide is not particularly limited as long as it can reduce at least the above impurities. For example, it can be obtained by purifying lithium sulfide produced by the following methods ac.
a. A method in which lithium hydroxide and hydrogen sulfide are reacted at 0 to 150 ° C. in an aprotic organic solvent to produce lithium hydrosulfide, and then this reaction solution is dehydrosulfurized at 150 to 200 ° C. 7-330312 gazette).
b. A method in which lithium hydroxide and hydrogen sulfide are reacted at 150 to 200 ° C. in an aprotic organic solvent to directly produce lithium sulfide (see JP-A-7-330312).
c. A method of reacting lithium hydroxide and a gaseous sulfur source at a temperature of 130 to 445 ° C. (see JP-A-9-283156).

There is no restriction | limiting in particular as a purification method of the lithium sulfide obtained as mentioned above. As a preferable purification method, for example, a purification method described in International Publication No. WO2005 / 40039 and the like can be mentioned. Specifically, the lithium sulfide obtained as described above is washed at a temperature of 100 ° C. or higher using an organic solvent.
The organic solvent used for washing is preferably an aprotic polar solvent, and more preferably, the aprotic organic solvent used for lithium sulfide production and the aprotic polar organic solvent used for washing are the same. .

  Examples of the aprotic polar organic solvent preferably used for washing include aprotic polar organic compounds such as amide compounds, lactam compounds, urea compounds, organic sulfur compounds, cyclic organophosphorus compounds, Or it can use suitably as a mixed solvent. In particular, N-methyl-2-pyrrolidone (NMP) is selected as a good solvent.

  The amount of the organic solvent used for washing is not particularly limited, and the number of times of washing is not particularly limited, but is preferably 2 or more. Cleaning is preferably performed under an inert gas such as nitrogen or argon.

  The washed lithium sulfide is dried at a temperature equal to or higher than the boiling point of the organic solvent used for washing for 5 minutes or more, preferably about 2 to 3 hours or more under an inert gas stream such as nitrogen under normal pressure or reduced pressure. Thus, lithium sulfide used in the present invention can be obtained.

Further, hydrogen sulfide gas is blown into a slurry composed of lithium hydroxide and a hydrocarbon-based organic solvent, the lithium hydroxide and hydrogen sulfide are reacted, and the reaction is continued while removing water generated by the reaction from the slurry. Then, after the water in the system has substantially disappeared, lithium sulfide can be produced by stopping the blowing of hydrogen sulfide and blowing an inert gas (Japanese Patent Laid-Open No. 2010-163356).
The lithium sulfide prepared by the above method may be once dried and then used for the next step, but may be used in the next step as a slurry.

Lithium sulfide is preferably atomized. Atomization of lithium sulfide can be performed by a physical method using a mill device or the like, a method of adding a polar solvent having one or more polar groups to lithium sulfide, and the like.
The physical method using a mill apparatus can be performed dry or wet. In the case of the dry type, a ball mill, a planetary ball mill, a jet mill device, or the like can be used.
In the case of a wet type, a solvent that can be used is a non-aqueous solvent such as hexane, heptane, octane, toluene, xylene, ethylbenzene, cyclohexane, methylcyclohexane, and petroleum ether. The same mill apparatus as the dry type can be used.
Moreover, the method of making slurry solution and supplying or circulating to a mill apparatus is also possible.

The technique performed by adding a polar solvent having one or more polar groups to lithium sulfide can be performed as follows.
Although it is possible to carry out only with a polar solvent, it is desirable to use a nonpolar solvent together to form a slurry.
Nonaqueous solvents at this time include hexane, heptane, octane, toluene, xylene, ethylbenzene, cyclohexane, methylcyclohexane, and petroleum ether.

The polar group of the polar solvent includes hydroxyl group, carboxy group, nitrile group, amino group, amide bond, nitro group, -C (= S) -bond, ether (-O-) bond, -Si-O- bond, ketone. (—C (═O) —) bond, ester (—C (═O) —O—) bond, carbonate (—O—C (═O) —O—) bond, —S (═O) — bond, A solvent having at least one polar group selected from chloro and fluoro is preferred.
Examples of polar solvents containing one kind of polar group include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, n-pentanol, water, ethylene glycol, formic acid, acetic acid, acetonitrile, propionitrile, malononitrile, Succinonitrile, fumaronitrile, trimethylsilyl cyanide, N-methylpyrrolidone, triethylamine, pyridine, dimethylformamide, dimethylacetamide, nitromethane, carbon disulfide, diethyl ether, diisopropyl ether, t-butyl methyl ether, phenylmethyl ether, dimethoxymethane, Diethoxyethane, tetrahydrofuran, dioxane, trimethylmethoxysilane, dimethyldimethoxysilane, tetramethoxysilane, tetraethoxysila , Cyclohexylmethyldimethoxysilane, acetone, methyl ethyl ketone, acetaldehyde, ethyl acetate, acetic anhydride, methylene carbonate, propylene carbonate, dimethyl sulfoxide, methylene chloride, chloroform, dichloroethane, dichlorobenzene, hexafluorobenzene, trifluoromethylbenzene, etc. Can be mentioned.
Examples of polar solvents containing two types of polar groups include 2,2,2-trifluoroethanol, hexafluoroisopropanol, 2-aminoethanol, chloroacetic acid, trifluoroacetic acid, methoxypropionitrile, 3-ethoxypropionitrile, Examples include methyl cyanoacetate and difluoroacetonitrile.

  The above polar solvent and non-polar solvent do not need to be dehydrated, but the amount of water may affect the amount of alkali metal hydroxide in the micronized product by-produced, so the amount of water is preferably 50 ppm or less. Preferably it is 30 ppm or less.

The concentration of the polar solvent in the solvent is preferably 0.1% by mass or more and 100% by mass or less. More preferably, it is 0.2 mass% or more, Most preferably, it is 0.5 mass% or more.
The solvent may be only a polar solvent.

  The boiling point of the polar solvent is preferably 40 ° C to 300 ° C, more preferably 45 ° C to 280 ° C under normal pressure. This range is preferable from the viewpoint of easy drying by removing the solvent under heating vacuum.

In atomization, it is desirable that the lithium sulfide be 0.5 to 1000 parts by mass with respect to 100 parts by mass of the solvent.
The treatment temperature varies depending on the boiling point and freezing point of the solvent used, but is preferably -100 ° C or higher and 100 ° C or lower, more preferably -80 ° C or higher and 80 ° C or lower. High temperature processing may not provide desirable results.
Although it is not necessary to pay particular attention to the influence of moisture, the above treatment is preferably performed in a sealed state or under an inert gas for stable synthesis of the product.
The treatment time is preferably 5 minutes to 1 week, more preferably 1 hour to 5 days.

  The atomization treatment can be performed in either the continuous phase or the batch phase. In the case of a batch reaction, a general blade can be used for stirring, and an anchor blade, a fiddler blade, a helical blade, and a Max blend blade are preferable. In the laboratory scale, a stirrer with a stirrer is generally used. In the batch reaction, a reaction vessel using a ball mill can be used.

  If necessary, the solvent is removed after the atomization treatment. When removing a polar solvent, it can carry out by heating under a vacuum, or by nonpolar solvent substitution, for example. Moreover, it can also substitute for a nonpolar solvent. When the step after the modification requires a slurry state, it can be stored in the slurry state after the solvent replacement.

The obtained atomized product is dried as necessary to remove the residual solvent. The drying treatment is preferably performed under a nitrogen stream or under vacuum. The drying temperature is preferably room temperature to 300 ° C.
Depending on the type of polar solvent, an alkali metal hydroxide may be produced as a by-product during the treatment. This hydroxide can be converted back to sulfide by introducing hydrogen sulfide gas into the atomized slurry solution.
This blowing of hydrogen sulfide can be performed in the non-aqueous solvent described above.

The surface area of the atomized lithium sulfide is preferably 1 m ² / g or more. This improves the reactivity and facilitates application to various reactions. The surface area of lithium sulfide is preferably 5~400m ² / g, particularly preferably in 10 to 300 m ² / g.
The surface area of lithium sulfide is a value measured by the BET method using nitrogen.

As long as diphosphorus pentasulfide (P ₂ S ₅ ) is industrially manufactured and sold, it can be used without particular limitation. The purity is preferably 95% or more, and more preferably 99% or more. In place of P ₂ S ₅ , elemental phosphorus (P) and elemental sulfur (S) in a corresponding molar ratio can also be used. Simple phosphorus (P) and simple sulfur (S) can be used without particular limitation as long as they are industrially produced and sold.

The glass of the present invention can be synthesized from the above lithium sulfide and phosphorous pentasulfide. The reaction is preferably performed in an organic solvent. Thereby, energy required for manufacture of glass can be reduced.
The ratio (molar ratio) of lithium sulfide to diphosphorus pentasulfide is usually 50:50 to 80:20, preferably 60:40 to 75:25.
The reaction solvent is preferably a non-aqueous solvent used in the above-described atomization treatment.
The reaction temperature is 50 to 210 ° C, preferably 60 to 180 ° C. When the temperature is high, the reaction and crystallization proceed at the same time, so the reaction does not proceed, and as a result, the residual lithium sulfide may increase. On the other hand, when the temperature is low, the reaction may not proceed.

  The reaction time is in the range of 1 to 200 hours, preferably 4 to 180 hours. If the reaction time is short, the reaction may not proceed. When the reaction time is long, crystallization may partially progress and ionic conductivity may decrease.

  The reaction concentration is preferably 0.1 to 70% by mass as the amount of the solid component that is the reaction substrate with respect to the reaction solvent. More preferably, it is 0.5-50 mass%. When it is higher than 70% by mass, uniform stirring may be difficult with a normal stirring blade. On the other hand, when it is less than 0.1% by mass, the productivity may be lowered.

The reaction can be performed in either a continuous phase or a batch phase.
As a batch type reaction vessel (reactor), a layer having a general stirring blade can be used. A reaction vessel provided with an anchor wing, a fiddler wing, a helical wing, and a max blend wing is preferable. In test studies, a stirrer with a stirrer is generally used.
In the case of a continuous phase, it is desirable to use a plug flow type reactor. A plurality of batches may be installed and used in series.

The obtained reaction product (solid electrolyte glass) may be used in the form of a slurry, or may be dried and used as a powder.
When used as a slurry, the supernatant can be removed after the reaction, or a non-aqueous solvent can be added and transferred to another container for use.
When used as a dry powder, it is necessary to remove the non-aqueous solvent. The removal of the solvent can be performed at room temperature or in a heating treatment under vacuum or under a nitrogen flow. The heating condition is preferably 50 to 160 ° C. When the temperature is higher than this, crystallization of the solid electrolyte proceeds, and the conductivity may decrease. On the other hand, when the temperature is low, the removal of the residual solvent may be insufficient.

  The residual solvent amount of the solid electrolyte obtained by the drying treatment is 5% by mass or less, and preferably 3% by mass or less. When the residual solvent is large, non-conductor (resistive component) is present in the electrolyte, so that the battery performance is lowered.

The suitable example of the manufacturing apparatus of the glass of this invention is demonstrated.
FIG. 3 is a diagram showing an embodiment of the glass manufacturing apparatus of the present invention.
The manufacturing apparatus 1 includes a pulverizer (crushing and synthesizing means) 10 that synthesizes an ion conductive substance that is glass by reacting while pulverizing the raw material, and a reaction tank (synthetic means) that synthesizes the ion conductive substance by reacting the raw material. ) 20. In this apparatus, the reaction tank 20 includes a container 22 and a stirring blade 24. The stirring blade 24 is driven by a motor (M).

  The pulverizer 10 is provided with a heater 30 (first temperature stabilizing means) through which hot water can be passed around the pulverizer 10 in order to keep the interior of the pulverizer 10 at 20 ° C. or higher and 80 ° C. or lower. The reaction tank 20 is in an oil bath 40 (second temperature stabilization means) in order to keep the inside of the reaction tank 20 at 40 ° C. or higher and 200 ° C. or lower. The oil bath 40 heats the raw material and solvent in the container 22 to a predetermined temperature. The reaction tank 20 is provided with a cooling pipe 26 that cools and vaporizes the evaporated solvent.

  The pulverizer 10 and the reaction tank 20 are connected by a first connecting pipe 50 and a second connecting pipe 52 (connecting means). The first connecting pipe 50 moves the raw material and solvent in the pulverizer 10 to the reaction tank 20, and the second connecting part 52 moves the raw material and solvent in the reaction tank 20 into the pulverizer 10. A pump 54 (for example, a diaphragm pump) (circulation means) is provided in the second connection pipe 52 in order to circulate the raw materials and the like through the connection pipes 50 and 52.

  When glass is produced using this apparatus 1, a hydrocarbon solvent and raw materials are supplied to the pulverizer 10 and the reaction tank 20, respectively. Hot water (HW) enters and exits the heater 30 (RHW). While maintaining the temperature in the pulverizer 10 at 20 ° C. or higher and 80 ° C. or lower by the heater 30, the raw materials are reacted while being pulverized in a hydrocarbon solvent to synthesize an ion conductive substance. While keeping the temperature in the reaction tank 20 at 40 ° C. or higher and 200 ° C. or lower by the oil bath 40, the raw materials are reacted in a hydrocarbon solvent to synthesize an ion conductive material. The temperature in the reaction vessel 20 is measured with a thermometer (Th). At this time, the stirring blade 24 is rotated by the motor (M) to stir the reaction system so that the slurry composed of the raw material and the solvent does not precipitate. Cooling water (CW) enters and exits the cooling pipe 26 (RCW). The cooling pipe 26 cools and liquefies the vaporized solvent in the container 22 and returns it to the container 22. While the ion conductive material is synthesized in the pulverizer 10 and the reaction tank 20, the raw material being reacted is circulated between the pulverizer 10 and the reaction tank 20 through the connecting pipes 50 and 52 by the pump 54. The temperature of the raw material and the solvent fed into the pulverizer 10 is measured by a thermometer (Th) provided in the second connecting pipe before the pulverizer 10.

  The crusher 10 may be any crusher as long as it can produce the glass by crushing and mixing the raw materials. For example, a rotary mill (rolling mill), a rocking mill, a vibration mill, and a bead mill can be used. A bead mill is preferable in that the raw material can be finely pulverized. The finer the raw material, the higher the reactivity, and the glass can be produced in a short time.

  When the pulverizer includes a ball, the ball is preferably made of zirconium, reinforced alumina, or alumina in order to prevent contamination of the glass due to wear of the ball and the container.

  Moreover, in order to prevent mixing of the balls from the pulverizer 10 to the reaction tank 20, a filter for separating the balls, the raw material, and the solvent may be provided in the pulverizer 10 or the first connecting pipe 50 as necessary.

  The pulverization temperature in the pulverizer is 20 ° C. or higher and 80 ° C. or lower, preferably 20 ° C. or higher and 70 ° C. or lower. When the processing temperature in the pulverizer is less than 20 ° C., the effect of shortening the reaction time required for production is small, and when it exceeds 80 ° C., the strength of zirconia, reinforced alumina, and alumina, which are the materials of containers and balls, is significantly reduced. For this reason, there is a possibility that the container and ball are worn and deteriorated, and foreign matter is mixed into the glass.

  The reaction tank 20 may be any reaction tank as long as the raw materials can be reacted to produce glass. Usually, the reaction tank has a container, mixing means such as a stirrer, and cooling means. The mixing means mixes the slurry composed of the raw material and the solvent in the container so that the slurry does not precipitate. The cooling means cools the evaporated solvent and returns it to the container.

  The container 22 is preferably made of metal or glass. When reacting at a reaction temperature equal to or higher than the boiling point of the solvent, it is preferable to use a pressure resistant container.

  The reaction temperature in the container 22 is 40 ° C. or higher and 200 ° C. or lower. 80 degreeC or more and 150 degrees C or less are preferable. If it is less than 60 degreeC, it takes time for vitrification reaction and production efficiency is not enough. If it exceeds 200 ° C., undesirable crystals may be precipitated.

  The reaction is preferably carried out at a high temperature because the region where the temperature is high is fast. However, when the pulverizer is heated to a temperature exceeding 80 ° C., mechanical problems such as wear occur. Therefore, it is necessary to set the reaction tank to a high reaction temperature and to keep the pulverizer at a relatively low temperature.

  The ratio between the capacity of the reaction tank 20 and the capacity of the pulverizer 10 may be arbitrary, but the capacity of the reaction tank 20 is usually about 1 to 100 times the capacity of the pulverizer 10.

FIG. 4 is a diagram showing another embodiment of the manufacturing apparatus.
The manufacturing apparatus 2 is the same as the manufacturing apparatus 1 described above except that a heat exchanger 60 (heat exchange means) is provided in the second connecting portion 52. The same members as those of the manufacturing apparatus 1 are denoted by the same reference numerals and description thereof is omitted.
The heat exchanger 60 cools the high-temperature raw material and solvent sent out from the reaction tank 20 and sends them to the stirrer 10. For example, when the reaction is performed at a temperature exceeding 80 ° C. in the reaction tank 20, the temperature of the raw material or the like is cooled to 80 ° C. or less and sent to the stirrer 10.

A glass ceramic is obtained by heat-treating the glass of the present invention at 200 ° C. or more and 400 ° C. or less, more preferably 230 to 350 ° C. By making it into glass ceramic, ion conductivity may be improved. Note that the glass may be partially crystallized.
The heat treatment time is preferably from 0.1 to 24 hours, particularly preferably from 0.5 to 12 hours.

  The heat treatment is preferably performed in an inert gas atmosphere such as nitrogen or argon. The dew point of the inert gas is preferably −20 ° C. or less, particularly preferably −40 ° C. or less. The pressure is usually from reduced pressure to 20 MPa, and it is preferable to dry under reduced pressure or to pass an inert gas at normal pressure.

Further, crystallization (ceramicization) treatment is possible even in a slurry form.
A hydrocarbon solvent can be used as a solvent in the crystallization step. As hydrocarbon solvents, saturated hydrocarbons such as hexane, pentane, 2-ethylhexane, heptane, decane, cyclohexane, etc., unsaturated hydrocarbons such as hexene, heptene, cyclohexene, toluene, xylene, decalin, ethylbenzene, 1,2, And aromatic hydrocarbons such as 3,4-tetrahydronaphthalene.

From the simplification of the process, it is preferable that the solvent for the crystallization step is the same as the solvent for the production of the solid electrolyte glass.
The hydrocarbon solvent is preferably dehydrated, and the water content is preferably 100 ppm or less, more preferably 30 ppm or less.

The amount of the solid electrolyte glass added to 1 L of solvent is about 0.001 to 1 kg. Preferably it is 0.005-0.5 Kg, More preferably, it is 0.01-0.3 Kg.
The temperature for crystallization of the glass is usually 150 to 400 ° C, preferably 200 to 350 ° C. If it is lower than 150 ° C, crystallization may not proceed, and if it is higher than 400 ° C, the ionic conductivity may decrease.
The crystallization time is preferably 5 minutes to 50 hours, more preferably 10 minutes to 40 hours. If the contact time is less than 5 minutes, crystallization may be insufficient, and if it exceeds 50 hours, production efficiency and ionic conductivity may be reduced.
The crystallization temperature and crystallization time may be combined with several conditions.

  When it is necessary to separate the produced solid electrolyte glass ceramic and the solvent, a known method such as decantation, filtration, centrifugation, or a combination thereof can be employed. The cake-like product obtained by separation can be dried under a flow of an inert gas such as nitrogen or argon, dry air, or under reduced pressure. Although there is no restriction | limiting in particular about the temperature in this case, Usually, it is 0 to 400 degreeC.

  The solid portion and the solvent may be separated and further washed with a suitable solvent. The washing solvent is not particularly limited as long as it can be used for crystallization, and may be the same as or different from the solvent used for crystallization. Moreover, a mixture may be sufficient.

Examples of the crystal structure of the glass ceramic include a Li ₇ PS ₆ structure, a Li ₄ P ₂ S ₆ structure, a Li ₃ PS ₄ structure, a Li ₄ SiS ₄ structure, and a Li ₂ SiS ₃ structure disclosed in JP-A-2002-109955. The Li ₇ P ₃ S ₁₁ structure disclosed in Japanese Patent Application Laid-Open No. 2005-228570 and WO 2007/065539 is preferable. The Li ₃ PS ₄ structure is particularly preferable as the crystal structure of the glass ceramic.

  Note that the crystallized portion of the sulfide-based solid electrolyte may be composed of only one crystal structure or may have a plurality of crystal structures.

The degree of crystallinity of the sulfide-based solid electrolyte (the degree of crystallinity of the crystal structure having higher ionic conductivity than that of the amorphous body) is preferably 50% or more, and more preferably 60% or more.
This is because when the crystallinity of the sulfide-based solid electrolyte is less than 50%, the effect of increasing the ionic conductivity by crystallization is reduced.
The degree of crystallinity can be measured by using an NMR spectrum apparatus. Specifically, a solid ³¹ P-NMR spectrum of a sulfide-based solid electrolyte was measured, and the resonance line observed at 70-120 ppm was separated into a Gaussian curve using a nonlinear least square method. It can be measured by determining the area ratio of each curve.

  The “glass” of the present invention means a state before the above-mentioned glass ceramicization, and may contain a small amount of crystal structure generated during glass production. Being glass can be confirmed by the fact that the peak due to the crystal is not observed by X-ray diffraction measurement or is small even if observed.

The glass and glass ceramic of the present invention (hereinafter, the glass and glass ceramic may be collectively referred to as the solid electrolyte of the present invention) are used in battery constituent layers, for example, a positive electrode, a solid electrolyte layer, and a negative electrode of a lithium ion battery. It can be suitably used as a solid electrolyte to be used. Particularly, it is suitable for the positive electrode and the solid electrolyte layer.
The positive electrode of this invention should just contain the solid electrolyte of this invention mentioned above, and can use a well-known member about other structural materials.
Examples of members other than the solid electrolyte of the present invention include a binder, a conductive additive, and other solid electrolytes.

  Examples of the binder include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), fluorine-containing resins such as fluorine rubber, thermoplastic resins such as polypropylene and polyethylene, ethylene-propylene-dienemer (EPDM), sulfonated EPDM, Natural butyl rubber (NBR) or the like can be used alone or as a mixture of two or more. In addition, an aqueous dispersion of cellulose or styrene butadiene rubber (SBR), which is an aqueous binder, can also be used.

As the conductive assistant, a conductive substance having an electric conductivity of 1.0 × 10 ³ S / m or more can be used. The substance is preferably 1.0 × 10 ⁴ S / m or more, and more preferably 1.0 × 10 ⁵ S / m or more.
The shape of the conductive material is not particularly limited, and may be a particulate conductive material, a plate-shaped conductive material, or a rod-shaped conductive material. For example, the plate-like conductive material may be graphene, the rod-like conductive material may be, for example, carbon nanotubes, etc., and the particulate conductive material may have a large surface area, a large pore volume, and an electronic conductivity. Examples include ketjen black and activated carbon, which have high properties.

Examples of the conductive substance include a carbon material, a metal powder, a metal compound, and the like, and preferably a carbon material. Since carbon has a high conductivity and is light, a battery having a high energy density per mass can be obtained.
More preferably, the conductive material is porous carbon having pores.
Examples of the porous carbon that is a conductive substance include carbon blacks such as ketjen black, acetylene black, denka black, thermal black, and channel black; and carbons such as graphite, carbon fiber, and activated carbon. These may be used alone or in combination of two or more.

When a positive electrode contains a conductive support agent, content of the conductive support agent in an electrode becomes like this. Preferably it is 0.01 to 90 mass%, More preferably, it is 0.01 to 50 mass% is there.
If the content of the conductive auxiliary is too large, the electric capacity may be reduced, and if the amount of the conductive auxiliary is small (or not included), the electric resistance may be increased.

When a positive electrode contains a binder, content of the binder in an electrode becomes like this. Preferably it is 0.01 to 90 mass%, More preferably, it is 0.01 to 10 mass%.
If the content of the binder is too large, the electric capacity may be reduced, and if the amount of the binder is small (or not included), the binding may be weakened.

The positive electrode of the present invention can be formed by, for example, a method in which the above material is press-molded by a usual method to form a sheet-like electrode. For example, when the solid electrolyte is glass, it may be pressed while heating at a temperature equal to or higher than the glass transition temperature, and some or all of the glassy solid electrolyte may be fused together, and heated above the crystallization temperature. A part or all of the glassy solid electrolyte may be converted to glass ceramic.
In addition, a method of forming a positive electrode material in a film shape on a current collector to form a positive electrode can be mentioned. Examples of the film forming method include an aerosol deposition method, a screen printing method, and a cold spray method. Furthermore, the method of apply | coating in a slurry form by disperse | distributing or partly dissolving in a solvent is mentioned. You may mix a binder as needed.

As the current collector, a plate-like body, a foil-like body, a mesh-like body, or the like made of stainless steel, gold, platinum, copper, zinc, nickel, tin, aluminum, or an alloy thereof can be used.
When used as the positive electrode layer, the layer thickness may be appropriately selected according to the battery design.

The lithium ion battery of this invention should just use the solid electrolyte of this invention mentioned above, and can use a well-known thing about other structures, such as a positive electrode, an electrolyte layer, and a negative electrode.
The solid electrolyte layer is a layer made of the solid electrolyte of the present invention or a known solid electrolyte, and is preferably a layer in which solid electrolyte particles are fused together. Here, fusion means that a part of the solid electrolyte particles is dissolved, and the dissolved part is integrated with other solid electrolyte particles. Further, the solid electrolyte layer may be a solid electrolyte plate, and the plate solid electrolyte layer is formed by dissolving a part or all of the solid electrolyte particles and bonding them together to form a plate. Including the case.
The thickness of the solid electrolyte layer is preferably 0.001 mm or more and 1 mm or less.

It is preferable that a negative electrode layer contains a negative electrode active material, an electrolyte, and a conductive support agent. Moreover, the binder may be included. The formation method and thickness are the same as in the case of the positive electrode.
As the negative electrode active material, a material capable of inserting and desorbing lithium ions, and a material known as a negative electrode active material in the battery field can be used.
For example, carbon materials, specifically artificial graphite, graphite carbon fiber, resin-fired carbon, pyrolytic vapor-grown carbon, coke, mesocarbon microbeads (MCMB), furfuryl alcohol resin-fired carbon, polyacene, pitch-based carbon Examples thereof include fibers, vapor-grown carbon fibers, natural graphite, and non-graphitizable carbon. Or it may be a mixture thereof. Preferably, it is artificial graphite.

Also, an alloy in combination with a metal itself such as metallic lithium, metallic indium, metallic aluminum, metallic silicon, or another element or compound can be used as the negative electrode material. Among these, silicon, tin, and lithium metal having a high theoretical capacity are preferable.
As the electrolyte and the conductive additive, the same electrode materials as described above can be used.

  The lithium ion battery of the present invention can be produced by a known method, for example, by a coating method or an electrostatic method (an electrostatic spray method, an electrostatic screen method, etc.).

[Production of lithium sulfide]
Production Example 1
(1) Production of lithium sulfide 270 g of toluene as a nonpolar solvent under a nitrogen stream was added to a 600 ml separable flask, 30 g of lithium hydroxide (Honjo Chemical Co., Ltd.) was added, and the mixture was stirred at 300 rpm with a full zone stirring blade. Held at 0C. The temperature was raised to 104 ° C. while blowing hydrogen sulfide into the slurry at a supply rate of 300 ml / min. From the separable flask, an azeotropic gas of water and toluene was continuously discharged. This azeotropic gas was dehydrated by condensing with a condenser outside the system. During this time, the same amount of toluene as the distilled toluene was continuously supplied to keep the reaction liquid level constant.

  The amount of water in the condensate gradually decreased, and no distillation of water was observed 6 hours after the introduction of hydrogen sulfide (the total amount of water was 22 ml). During the reaction, the solid was dispersed and stirred in toluene, and there was no moisture separated from toluene. Thereafter, the hydrogen sulfide was switched to nitrogen and circulated at 300 ml / min for 1 hour. The solid content was filtered and dried to obtain white powder of lithium sulfide.

When the obtained powder was analyzed by hydrochloric acid titration and silver nitrate titration, the purity of lithium sulfide was 99.0% by mass. Further, X-ray diffraction measurement confirmed that no peaks other than the crystal pattern of lithium sulfide were detected.
It was 14.8 m < ² > / g when the specific surface area of the obtained lithium sulfide was measured using AUTOSORB6 by the BET method by nitrogen gas.

The average particle diameter of lithium sulfide was measured using a laser diffraction particle size distribution analyzer (Mastersizer 2000 manufactured by Malvern Instruments Ltd). The average particle size was 450 μm (measured with slurry).
A specific measurement method is as follows.
First, 110 ml of dehydrated toluene (Wako Pure Chemicals, product name: special grade) was placed in the dispersion tank of the apparatus, and 6% of dehydrated tertiary butyl alcohol (Wako Pure Chemicals, special grade) was added as a dispersant. Added. After mixing well, a solid electrolyte is added and the particle size is measured.
Here, the addition amount of the solid electrolyte is adjusted so that the laser scattering intensity corresponding to the particle concentration falls within the specified range (10 to 20%) on the operation screen specified by the above apparatus. If this range is exceeded, multiple scattering may occur, and an accurate particle size distribution may not be obtained. On the other hand, when the amount is less than this range, the SN ratio is deteriorated, and there is a possibility that accurate measurement cannot be performed. In the above apparatus, since the laser scattering intensity is displayed based on the addition amount of the solid electrolyte-containing composition, the addition amount falling within the laser scattering intensity range is found.
As described above, the amount of solid electrolyte added varies depending on the concentration, but is generally about 10 μL to 200 μL.

The ionic component of the obtained aqueous solution of lithium sulfide was analyzed. Specifically, about 1 g of lithium sulfide was dissolved in 20 ml of water, and a part of the aqueous solution was collected and measured.
Measuring device: Dionex DX-120 manufactured by Dionex
Measurement column: cation chromatography CS12A; anion chromatography AS12A
The results are shown in Table 1.
As can be seen from the table, lithium sulfide is separated into ionic components and no other components are by-produced. Components other than Li ⁺ and S ²⁻ are impurity components.

(2) Atomization treatment A
(A) Atomization treatment 26.0 g of lithium sulfide produced in (1) above was weighed in a glove box and placed in a Schlenk bottle. In a Schlenk bottle, 507 ml of dehydrated toluene (manufactured by Wako Pure Chemical Industries) and 252 ml of dehydrated ethanol (manufactured by Wako Pure Chemical Industries) were added in this order, and the mixture was stirred with a stirrer at room temperature for 24 hours to obtain atomized lithium sulfide.

(B) Treatment with hydrogen sulfide gas After the above treatment, the bath temperature was raised to 120 ° C., and hydrogen sulfide gas was further circulated for 90 minutes while flowing hydrogen sulfide gas at 100 ml / min. While toluene was distilled, dehydrated toluene was added to maintain the slurry state. After flowing the hydrogen sulfide gas, the solvent was distilled off under a nitrogen stream at room temperature, and further treated at 200 ° C. for 2 hours under vacuum to recover atomized lithium sulfide.

Lithium sulfide atomized in the same manner as in (1) above was evaluated. As a result, the lithium sulfide had a purity of 97.5% by mass, an amount of lithium hydroxide of 0.5% by mass, an average particle size of 11.9 μm (slurry), a specific surface area of 46 m ² / g, and a pore volume of 0.53 ml / g. It was. Purity and lithium hydroxide content were each determined by titration. The total analysis value does not become 100% because, like Table 1, it contains impurities such as lithium carbonate, other ionic salts, and residual solvents.

(3) Atomization treatment B
In the above (2), atomization was performed in the same manner except that 6.9 ml of methanol was used instead of ethanol.
As a result, the obtained lithium sulfide had a purity of 95.5% by mass, an amount of lithium hydroxide of 1.2% by mass, an average particle size of 13.7 μm, a specific surface area of 24.6 m ² / g, and a pore volume of 0.36 ml / g. Met.

Production Example 2
(1) Production of lithium sulfide Lithium sulfide was produced according to the method of the first aspect (two-step method) in JP-A-7-330312. Specifically, N-methyl-2-pyrrolidone (NMP) 3326.4 g (33.6 mol) and lithium hydroxide 287.4 g (12 mol) were charged into a 10 liter autoclave equipped with a stirring blade, and 300 rpm, 130 ° C. The temperature was raised to. After the temperature rise, hydrogen sulfide was blown into the liquid at a supply rate of 3 liters / minute for 2 hours. Subsequently, the temperature of the reaction solution was raised under a nitrogen stream (200 cc / min), and the reacted lithium hydrosulfide was dehydrogenated to obtain lithium sulfide. As the temperature increased, water produced as a by-product due to the reaction between hydrogen sulfide and lithium hydroxide started to evaporate, but this water was condensed by the condenser and extracted out of the system. While water was distilled out of the system, the temperature of the reaction solution rose, but when the temperature reached 180 ° C., the temperature increase was stopped and the temperature was kept constant. The reaction was completed after the dehydrosulfurization reaction of lithium hydrosulfide (about 80 minutes) to obtain lithium sulfide.

(2) Purification of lithium sulfide After decanting NMP in the 500 mL slurry reaction solution (NMP-lithium sulfide slurry) obtained in (1) above, 100 mL of dehydrated NMP was added and stirred at 105 ° C. for about 1 hour. . NMP was decanted at that temperature. Further, 100 mL of NMP was added, stirred at 105 ° C. for about 1 hour, NMP was decanted at that temperature, and the same operation was repeated a total of 4 times. After completion of the decantation, lithium sulfide was dried at 230 ° C. (temperature higher than the boiling point of NMP) under a nitrogen stream for 3 hours under normal pressure. The impurity content in the obtained lithium sulfide was measured.

Incidentally, lithium sulfite _(Li 2 _SO 3), the content of each sulfur oxide lithium sulfate _(Li 2 SO ₄₎ and lithium thiosulfate _{(Li 2 S 2 O 3)} , and N- methylamino acid lithium (LMAB) Was quantified by ion chromatography. As a result, the total content of sulfur oxides was 0.13% by mass, and lithium N-methylaminobutyrate (LMAB) was 0.07% by mass. The average particle size was 190 μm (slurry solution).

Example 1 (solid electrolyte glass)
The autoclave containing the stirrer chip was replaced with nitrogen, and 1.2 g (75 mol%) of atomized Li ₂ S produced in Production Example 1 (2), 1.88 g of diphosphorus pentasulfide (manufactured by Aldrich, 25 mol%), moisture 30 ml of toluene (manufactured by Wako Pure Chemical Industries, Ltd.) dehydrated to a content of 10 ppm was charged and reacted at 150 ° C. for 72 hours to obtain a solid electrolyte glass (slurry).
By placing the solid electrolyte glass slurry under vacuum at room temperature, the toluene was volatilized to form a powdery glass. The powdery glass was further vacuum dried at 150 ° C. for 2 hours.
This glass was in the form of powder, and its ionic conductivity was measured and found to be 1.25 × 10 ⁻⁴ S / cm. The ionic conductivity was measured by the AC impedance method.

The glass is mainly composed of an amorphous component, and the raw material lithium sulfide remains. Although the amorphous component shows only a broad peak as shown in FIG. 6 described later, since the raw material lithium sulfide is crystallized, a peak due to lithium sulfide is observed.
As a result of selecting about 27 ° as the largest peak due to lithium sulfide and evaluating its strength, it was 1850. The baseline was set by performing straight line correction from the lowest value of 2 ° in the front and rear direction.
As a standard sample, a sample obtained by mixing 1.2 g of lithium sulfide and 1.88 g of diphosphorus pentasulfide was used. The intensity of the peak at about 27 ° was about 15500.
From the intensity ratio of the peak at about 27 °, the residual ratio of lithium sulfide is 11.9%.

From the measurement by gas chromatography, the residual solvent amount of the glass was 2.2% by mass.
The particle size distribution of the glass was measured with a laser diffraction particle size distribution analyzer. The results are shown in FIG. It can be seen that the average particle diameter is 17.8 μm, and there are no particles of 50 μm or more.

The hydrogen sulfide concentration, which is an index of hydrolysis resistance, was measured by the following method.
The measurement sample was well pulverized with a mortar in a nitrogen glow box in an environment with a dew point of −60 ° C. or lower. The measurement sample was sealed in a 0.1 g, 100 ml Schlenk bottle.
Next, the air (wet air) humidified by passing the water tank through the Schlenk bottle is circulated at 500 ml / min. The temperature of the wet air is about 25 ° C., and the humidity is 80 to 90%. In addition, the air supply amount is controlled by a flow meter.
From 1 minute to 1 minute 45 seconds after the start of distribution, the gas after distribution is collected and used as a sample gas for measurement.

  Using TS-100 manufactured by Mitsubishi Chemical Analytech, the sulfur content is quantified by the ultraviolet fluorescence method, and the hydrogen sulfide concentration of the sample gas is calculated. When the sample gas was qualitatively analyzed with a gas chromatograph using an Agilent 6890 (with a sulfur selective detector (SIEVERS 355)), it was confirmed that the sulfur content was 99% or more of hydrogen sulfide gas.

Between 5 minutes and 5 minutes and 45 seconds after the start of distribution, between 10 minutes and 10 minutes and 45 seconds after the start of distribution, between 20 minutes and 20 minutes and 45 seconds after the start of distribution, and between 60 minutes and 60 minutes after the start of distribution The gas discharged from the Schlenk bottle after 45 seconds is similarly measured. From this measurement result, the maximum hydrogen sulfide gas amount (maximum concentration) was evaluated.
As a result, the maximum concentration was 86 ppm (gas collected 5 minutes to 5 minutes 45 seconds after the start of distribution).
In addition, the maximum concentration of hydrogen sulfide gas is 1440 ppm (gas collected from 5 minutes to 5 minutes and 45 seconds after the start of distribution) for a standard sample (sample obtained by mixing 1.2 g of lithium sulfide and 1.88 g of diphosphorus pentasulfide). there were.

Example 2
The solid electrolyte glass obtained in Example 1 was heat treated under vacuum at 300 ° C. for 2 hours to form a glass ceramic. The obtained glass ceramic was in the form of powder, and its ionic conductivity was measured and found to be 1.26 × 10 ⁻⁴ S / cm.
Thus, it can be seen that even if the solid electrolyte glass in which lithium sulfide remains is crystallized, ion conductivity equivalent to that in the solid electrolyte glass in which lithium sulfide remains can be obtained.
The residual solvent amount of the glass ceramic was 0.1% by mass or less (below the detection lower limit).
The maximum concentration of hydrogen sulfide gas was 5 ppm (the gas collected at 5 minutes to 5 minutes and 45 seconds from the same time as the gas collected from 1 minute to 1 minute and 45 seconds after the start of flow).

Example 3
A solid electrolyte glass was produced and evaluated in the same manner as in Example 1 except that the atomized Li ₂ S produced in Production Example 1 (3) was used.
The ionic conductivity was 1.12 × 10 ⁻⁴ S / cm. The residual ratio of lithium sulfide was 12.8%. The amount of residual solvent was 2.3% by mass.
The maximum concentration of the hydrogen sulfide gas was 97 ppm (gas collected from 5 minutes to 5 minutes and 45 seconds after the start of distribution).

Example 4
The lithium sulfide prepared in Production Example 1 (1) was pulverized using a jet mill apparatus (manufactured by Aisin Nano Technology) in a nitrogen atmosphere. The recovered lithium sulfide had a surface area of 20 m ² / g and a particle size of 2.1 μm.
An electrolyte glass was prepared in the same manner as in Example 1 using 1 g of lithium sulfide pulverized by a jet mill apparatus and 1.61 g of diphosphorus pentasulfide.
The residual peak intensity of lithium sulfide in the electrolyte glass was 2050, the residual amount of lithium sulfide was 13.2%, and the ionic conductivity was 1.2 × 10 ⁻⁴ S / cm.

Example 5
The apparatus shown in FIG. 3 was used. As a stirrer, 450 g of 0.5 mmφ zirconia balls were charged using a star mill mini-zea (0.15 L) (bead mill) manufactured by Ashizawa Finetech. A 1.5 L glass reactor with a stirrer was used as a reaction vessel.
The above weighing, addition and sealing operations were all carried out in the glove box, and all the instruments used were water removed beforehand by a dryer. In addition, dehydrated toluene was 8.4 ppm as measured by the Karl Fischer method.

Reaction of a mixture obtained by adding 1248 ml of dehydrated toluene (moisture content: 8.4 ppm) manufactured by Hiroshima Wako Pure Chemical Industries, Ltd. to 42.0 g of lithium sulfide (not refined) in Production Example 2 and 67.8 g of diphosphorus pentasulfide Filled tank and mill.
The contents were circulated at a flow rate of 400 mL / min by a pump, and the temperature of the reaction vessel was increased to 80 ° C.
The mill body was run for 8 hours under conditions of a peripheral speed of 8 m / s by passing warm water through external circulation so that the liquid temperature could be maintained at 70 ° C.
The obtained slurry was filtered and air-dried, and then dried with a tube heater at 150 ° C. for 2 hours to obtain a solid electrolyte glass powder. The recovery rate at this time was 95%, and no adhesion was observed in the reactor.
As a result of X-ray diffraction measurement (CuKα: λ = 1.5418４) of the obtained powder, it was a halo pattern resulting from the solid electrolyte glass, and the remaining lithium sulfide could be observed.
The ionic conductivity of this electrolyte glass was 2.0 × 10 ⁻⁴ S / cm.
The Li ₂ S residual peak intensity in X-ray diffraction measurement was 950, and the Li ₂ S residual amount was calculated to be 6.1%.

Comparative Example 1
Using the lithium sulfide produced in Production Example 2, a sulfide-based glass was produced by a method in accordance with Example 1 of International Publication No. WO07 / 0666539. Specifically, it was performed as follows.
0.383 g (0.00833 mol, 75 mol%) of lithium sulfide produced in Production Example 2 and 0.618 g (0.00278 mol, 25 mol%) of diphosphorus pentasulfide (Aldrich) were mixed well. Then, the mixed powder, 10 zirconia balls having a diameter of 10 mm, and a planetary ball mill (manufactured by Fritsch Co., Ltd .: Model No. P-7) are put into an alumina pot and completely sealed, and the alumina pot is filled with nitrogen, The atmosphere was nitrogen.
Then, for the first few minutes, the planetary ball mill was rotated at a low speed (85 rpm) to sufficiently mix lithium sulfide and diphosphorus pentasulfide. Thereafter, the rotational speed of the planetary ball mill was gradually increased to 370 rpm. Mechanical milling was performed for 20 hours at a rotational speed of the planetary ball mill at 370 rpm to obtain glass. As a result of evaluating the mechanically milled white yellow powder by X-ray measurement, it was confirmed that the powder was vitrified (sulfide glass). FIG. 6 shows an X-ray diffraction spectrum of the solid electrolyte glass produced in Comparative Example 1.

When the ionic conductivity of the obtained solid electrolyte glass was measured, it was 1.3 × 10 ⁻⁴ S / cm. Moreover, the maximum concentration of hydrogen sulfide gas was 66 ppm (gas collected from 5 minutes to 5 minutes 45 seconds after the start of distribution).
Further, the residual ratio of lithium sulfide was 0%.
When each example and Comparative Example 1 are compared, there is no difference in the maximum concentration (generation amount) of hydrogen sulfide gas, and there is no difference in the generation amount of hydrogen sulfide even if a predetermined amount of lithium sulfide remains in the solid electrolyte. I was able to confirm.

The Raman spectra of the glasses obtained in Examples 1, 3 to 5 and Comparative Example 1 were measured under the following conditions.
・ Laser Raman measurement conditions Measurement device: Almega manufactured by Thermo Fisher Scientific Co., Ltd.
Laser wavelength: 532 nm
Laser power: 10%
Aperture: 25μmφ
Exposure time: 10 seconds Number of exposures: 10 Objective lens: x100
Resolution: High (2400 lines / mm)

The Raman spectrum was measured 5 times after the same lot sample was sealed in a Raman tube and the measurement position was changed.
About the measured spectrum, it separated into each peak using waveform analysis software (Thermo SCIENTIFIC make: GRAMS AI).
Table 2 shows the average value and standard deviation of the area ratios of the separated peaks.

The glass and glass ceramic of the present invention can be suitably used as an electrolyte or electrode material for an all-solid battery.
The lithium ion battery of the present invention can be used as a battery for a portable information terminal, a portable electronic device, a small electric power storage device for home use, a motorcycle using a motor as a power source, an electric vehicle, a hybrid electric vehicle, or the like.

1, 2 Production equipment 10 Crusher (Mechanical energy supply means)
20 Reaction tank (contact means)
22 container 24 stirring blade 26 cooling pipe 30 heater 40 oil bath 50 first connection pipe (connection means)
52 Second connecting pipe (connecting means)
54 Pump (circulation means)
60 heat exchanger

Claims (8)

A glass containing lithium element (Li), phosphorus element (P) and sulfur element (S),
The Raman spectrum of the glass was measured 5 times or more, the peaks of 330 to 450 cm ^{−1 in} the Raman spectrum were separated into waveforms, and the standard deviation of the area ratio separated into each component was 3.0 or less,
The area of the peak of PS ₄ ^3- component obtained by the waveform separation is 10 to 95% of the whole, the area of the peak of the same P ₂ S ₇ ^4- component is 5 to 45% of the whole,
The PS ₄ ^3- component peak area is wider than the P ₂ S ₇ ^4- component peak area,
The glass contains a solvent, and the residual amount of the solvent is 5% by mass or less;
Glass whose ionic conductivity is 1.0 × 10 ⁻⁴ S / cm or more. The glass according to claim 1, wherein the residual amount of lithium sulfide by X-ray diffraction analysis is 0.1% or more and 30% or less. The glass according to claim 1 or 2, wherein both of the standard deviations are 2.5 or less. The glass according to claim 1, wherein the solvent is an organic solvent. The glass according to any one of claims 1 to 4, wherein an element ratio (Li: P, molar ratio) between the Li element and the P element is 70: 30 ≦ Li: P ≦ 83: 17. The glass according to any one of claims 1 to 5 , wherein the average particle size is 20 µm or less and the content of particles having a particle size of 50 µm or more is 3 mass% or less. The positive electrode containing the glass according to any one of claims 1-6. Lithium-ion battery comprising a layer containing a glass as claimed in any one of claims 1-6.

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