JP2018170184A - Lithium-phosphorus-oxygen-nitrogen based inorganic solid electrolytic material, solid electrolyte, solid electrolyte film, lithium ion battery and method for manufacturing lithium-phosphorus-oxygen-nitrogen based inorganic solid electrolytic material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a particulate oxide-based inorganic solid electrolytic material which is superior in balance between electrochemical stability and lithium ion conductivity.SOLUTION: A Li-P-O-N based inorganic solid electrolytic material of the present invention is a particulate Li-P-O-N based inorganic solid electrolytic material having lithium ion conductivity and comprising as constituent elements, Li, P, O and N. In the Li-P-O-N based inorganic solid electrolytic material, a mole ratio (Li/P) of a Li content to a P content is 3.5 or more and 100.0 or less; a mole ratio (O/P) of an O content to the P content is 2.0 or more and 6.0 or less; and a mole ratio (N/P) of a N content to the P content is 0.1 or more and 31.0 or less.SELECTED DRAWING: None

Description

  The present invention relates to a Li—P—O—N inorganic solid electrolyte material, a solid electrolyte, a solid electrolyte membrane, a lithium ion battery, and a method for producing a Li—P—O—N inorganic solid electrolyte material.

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

  An electrolyte solution containing a flammable organic solvent is used in a lithium ion battery currently on the market. On the other hand, a lithium ion battery (hereinafter also referred to as an all-solid-state lithium ion battery) in which the electrolyte is changed to a solid electrolyte to make the battery completely solid does not use a flammable organic solvent in the battery. It is considered that the manufacturing cost and productivity are excellent.

  As solid electrolyte materials used for such solid electrolytes, for example, sulfide-based inorganic solid electrolyte materials and oxide-based inorganic solid electrolyte materials are 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 CuKα rays, and Li _{2y + 3} PS ₄ (0 .1 ≦ y ≦ 0.175), a sulfide-based solid electrolyte material is described.

  Patent Document 2 (Japanese Patent Application Laid-Open No. 2011-171248) discloses an oxidation made of lithium nitride phosphate having an atomic ratio (Li / P) of a lithium atom to a phosphorus atom contained of 3.0 or more and 6.0 or less. Physical inorganic solid electrolyte materials are described.

  Patent Document 3 (Japanese Patent Application Laid-Open No. 2011-171247) discloses an oxidation comprising lithium nitride phosphate having an atomic ratio (Li / P) of lithium atoms to phosphorus atoms of 1.0 or more and 2.3 or less. Physical inorganic solid electrolyte materials are described.

JP 2016-27545 A JP 2011-171248 A JP 2011-171247 A

The oxide-based inorganic solid electrolyte material has the advantages that the raw material is inexpensive and is easier to handle than the sulfide-based inorganic solid electrolyte material. However, the oxide-based inorganic solid electrolyte material is harder than the sulfide-based inorganic solid electrolyte material and has low adhesion between particles. Therefore, it has a defect that the grain boundary resistance is high and the lithium ion conductivity is inferior to that of the sulfide-based inorganic solid electrolyte material.
From the above, oxide-based inorganic solid electrolyte materials used for lithium ion batteries are required to further improve lithium ion conductivity while having electrochemical stability.
Here, although the oxide-based inorganic solid electrolyte material composed of lithium lithium phosphate described in Patent Documents 2 and 3 is excellent in lithium ion conductivity, it is a dense material manufactured using a high-frequency sputtering method in a nitrogen atmosphere. Because it is a thin-film solid electrolyte, its productivity, versatility, and handleability are inferior, making it impractical.

  The present invention has been made in view of the above circumstances, and provides a particulate oxide-based inorganic solid electrolyte material having an excellent balance between electrochemical stability and lithium ion conductivity.

  In order to provide a particulate oxide-based inorganic solid electrolyte material having an excellent balance between electrochemical stability and lithium ion conductivity, the present inventors have prepared the types of raw materials used in the production of the solid electrolyte material, and the blending ratio thereof. And so on. As a result, the particulate Li—P—O—N inorganic solid electrolyte material containing Li, P, O, and N in specific proportions as constituent elements is excellent in the balance between electrochemical stability and lithium ion conductivity. As a result, they have reached the present invention.

That is, according to the present invention,
A particulate Li—P—O—N inorganic solid electrolyte material having lithium ion conductivity and containing Li, P, O and N as constituent elements,
The molar ratio (Li / P) of the content of Li to the content of P in the Li-P-O-N-based inorganic solid electrolyte material is 3.5 or more and 100.0 or less, and the content of P The molar ratio (O / P) of the content of O to the amount is 2.0 or more and 6.0 or less, and the molar ratio (N / P) of the content of N to the content of P is 0.1. A Li—P—O—N-based inorganic solid electrolyte material that is 31.0 or less is provided.

Furthermore, according to the present invention,
A solid electrolyte containing the Li—P—O—N-based inorganic solid electrolyte material is provided.

Furthermore, according to the present invention,
There is provided a solid electrolyte membrane containing the solid electrolyte as a main component.

Furthermore, according to the present invention,
A lithium ion battery comprising a positive electrode including a positive electrode active material layer, an electrolyte layer, and a negative electrode including a negative electrode active material layer,
Provided is a lithium ion battery in which at least one of the positive electrode active material layer, the electrolyte layer, and the negative electrode active material layer contains the Li-P-O-N inorganic solid electrolyte material.

Furthermore, according to the present invention,
A manufacturing method for manufacturing the Li-P-O-N-based inorganic solid electrolyte material,
A method for producing a Li—P—O—N-based inorganic solid electrolyte material including a step of vitrifying the mixture A containing lithium phosphate and lithium nitride is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the particulate oxide type inorganic solid electrolyte material excellent in the balance of electrochemical stability and lithium ion conductivity can be provided.

It is sectional drawing which shows an example of the structure of the lithium ion battery of embodiment which concerns on this invention. It is a figure which shows the X-ray-diffraction spectrum of the oxide type inorganic solid electrolyte material obtained in Examples 1-12 and Comparative Example 1. FIG. 6 is a diagram showing an X-ray diffraction spectrum of an oxide-based inorganic solid electrolyte material obtained in Comparative Example 2. FIG.

  Embodiments of the present invention will be described below with reference to the drawings. In all the drawings, similar constituent elements are denoted by common reference numerals, and description thereof is omitted as appropriate. Moreover, the figure is a schematic diagram and does not match the actual dimensional ratio. “A to B” in the numerical range represents A or more and B or less unless otherwise specified.

[Li-P-O-N inorganic solid electrolyte material]
First, the Li—P—O—N inorganic solid electrolyte material according to the present embodiment will be described.
The Li—P—O—N-based inorganic solid electrolyte material according to the present embodiment has lithium ion conductivity and contains Li, P, O, and N as constituent elements. And the Li-P-ON-based inorganic solid electrolyte material according to this embodiment is a molar ratio of the content of Li to the content of P in the Li-P-ON-based inorganic solid electrolyte material. (Li / P) is 3.5 or more and 100.0 or less, and the molar ratio (O / P) of the content of O to the content of P is 2.0 or more and 6.0 or less. The molar ratio (N / P) of the N content to the N content is from 0.1 to 31.0.
Here, the contents of Li, P, O, and N in the Li—P—O—N inorganic solid electrolyte material according to the present embodiment can be determined by, for example, ICP emission spectroscopic analysis or X-ray analysis.

  The Li—P—O—N-based inorganic solid electrolyte material according to the present embodiment may not use sulfide as a raw material in order to improve the advantages of the oxide-based inorganic solid electrolyte material, that is, the raw material cost and handleability. preferable. That is, it is preferable that the Li—P—O—N inorganic solid electrolyte material according to the present embodiment does not contain S as a constituent element.

By setting the molar ratio of Li / P, the molar ratio of O / P, and the molar ratio of N / P within the above ranges, excellent lithium ion conductivity can be obtained. Although the reason for this is not necessarily clear, the following reason is presumed.
First, in order to improve the ionic conductivity of the solid electrolyte material, it is important to soften the solid electrolyte material while maintaining the stability of the compound and improve the adhesion between the particulate solid electrolyte materials. It is considered that when the adhesion between the particles is improved, the grain boundary resistance is lowered and the lithium ion conductivity can be improved.
For example, by increasing the Li composition and the N composition relative to the stable compound Li ₃ PO _{4, the} average molecular weight is increased and the ion filling rate is decreased. As a result, the Young's modulus of the solid electrolyte material is reduced and softened, and the adhesion between the particles can be improved.
That is, the Li—P—O—N inorganic solid electrolyte material according to this embodiment in which the molar ratio of Li / P, the molar ratio of O / P, and the molar ratio of N / P are within the above ranges is a stable compound. with Li composition and N composition compared to the _Li 3 PO ₄ is increased, considered Young's modulus becomes softer lower than _Li 3 PO _4.
Therefore, when the molar ratio of Li / P, the molar ratio of O / P, and the molar ratio of N / P are within the above ranges, the stability of the compound, the Li composition, and the adhesion between particles are highly balanced, As a result, it is thought that it led to the expression of high ionic conductivity.

Here, in the Li—P—O—N based inorganic solid electrolyte material according to the present embodiment, the Li / P is 3.5 or more, but from the viewpoint of further improving the lithium ion conductivity, 4.0 or more. Is preferably 4.5 or more, more preferably 5.5 or more, still more preferably 6.0 or more, still more preferably 7.5 or more, still more preferably 9.0 or more, and even more preferably 10.0 or more More preferably, 12.0 or more is particularly preferable.
Further, in the Li—P—O—N based inorganic solid electrolyte material according to the present embodiment, the Li / P is 100.0 or less, but preferably 90. From the viewpoint of further improving the electrochemical stability. It is 0 or less, More preferably, it is 80.0 or less, More preferably, it is 70.0 or less, Especially preferably, it is 65.0 or less.

  In the Li—P—O—N-based inorganic solid electrolyte material according to the present embodiment, the O / P is 2.0 or more and 6.0 or less, preferably 3.0 or more and 5.0 or less. More preferably, it is 3.5 or more and 4.5 or less, More preferably, it is 3.6 or more and 4.4 or less, More preferably, it is 3.8 or more and 4.2 or less, Especially preferably, it is 4.0. It is.

Further, in the Li—P—O—N based inorganic solid electrolyte material according to the present embodiment, the N / P is 0.1 or more, but from the viewpoint of further improving the lithium ion conductivity, 0.3 or more Preferably, 0.5 or more is more preferable, 0.8 or more is further preferable, 1.0 or more is further more preferable, 1.5 or more is further more preferable, 2.0 or more is further more preferable, and 3.0 or more is Particularly preferred.
Further, in the Li—P—O—N based inorganic solid electrolyte material according to the present embodiment, the N / P is 31.0 or less, but from the viewpoint of further improving the electrochemical stability, preferably 28. It is 0 or less, More preferably, it is 25.0 or less, More preferably, it is 22.0 or less, Most preferably, it is 20.0 or less.

In the Li—P—O—N-based inorganic solid electrolyte material according to the present embodiment, in a spectrum obtained by X-ray diffraction using CuKα rays as a radiation source, at a diffraction angle 2θ = 15.0 ± 0.1 °. the maximum diffraction intensity and background intensity _{I a,} when a diffraction intensity of a diffraction peak at the position of the diffraction angle 2θ = 33.0 ± 0.5 ° was _{I B,} the value of I B / _{I a} is preferably 50 or less, more preferably 30 or less, still more preferably 20 or less, and particularly preferably 15 or less.
The I B _/ I _A With more than the above upper limit, it is possible to further improve the lithium ion conductivity of the Li-P-O-N-based inorganic solid electrolyte material. Furthermore, when such a Li—P—O—N-based inorganic solid electrolyte material is used, a lithium ion battery more excellent in input / output characteristics can be obtained.

Here, the maximum diffraction intensity _{I A} at the position of the diffraction angle 2θ = 15.0 ± 0.1 °, a diffraction intensity of the reference, at the position of the diffraction angle 2θ = 33.0 ± 0.5 ° diffraction The peak is a diffraction peak derived from lithium phosphate.
_Therefore, I B / _{I A} represents an indication of the Li-P-O-N-based content of the lithium phosphate inorganic solid electrolyte material. As I B _/ I _A is small, the process proceeds vitrification, means that less amount of lithium phosphate is a raw material.
Since lithium phosphate has low lithium ion conductivity, it is considered that the lithium ion conductivity of the Li—P—O—N inorganic solid electrolyte material is improved as the lithium phosphate content is reduced.
Although the lower limit is not particularly limited because preferably as the I B _/ I _A small as possible, for example, 0.01 or more.

In the Li—P—O—N-based inorganic solid electrolyte material according to the present embodiment, a diffraction angle 2θ = 32.0 ± 0.4 ° in a spectrum obtained by X-ray diffraction using CuKα rays as a radiation source. It preferably has a diffraction peak.
The Li—P—O—N-based inorganic solid electrolyte material having such a diffraction peak is more excellent in lithium ion conductivity, and a lithium ion battery more excellent in input / output characteristics can be obtained.
Further, in the Li—P—O—N inorganic solid electrolyte material according to the present embodiment, the diffraction angle 2θ = 15.0 ± 0.1 ° in the spectrum obtained by X-ray diffraction using CuKα ray as the radiation source. maximum diffraction intensity and background intensity _{I a} at the position, when the diffraction intensity of the diffraction peak at the position of the diffraction angle 2θ = 32.0 ± 0.4 ° was _{I C,} the values of I C / _{I a} Preferably it is 2.0 or more, More preferably, it is 3.0 or more, More preferably, it is 5.0 or more, Most preferably, it is 6.0 or more.
By the values of I C _/ I _A is not less than the above lower limit, it is possible to further improve the lithium ion conductivity of the Li-P-O-N-based inorganic solid electrolyte material. Furthermore, when such a Li—P—O—N-based inorganic solid electrolyte material is used, a lithium ion battery more excellent in input / output characteristics can be obtained.
Here, it has a diffraction peak at a diffraction angle 2θ = 32.0 ± 0.4 °, or the value of _I C / _{I A} With than the above lower limit, Li-P-O-N-based The reason why the lithium ion conductivity of the inorganic solid electrolyte material can be further improved is not clear, but the following reasons are conceivable.
First, Li ₃ N used as a raw material of the Li—P—O—N-based inorganic solid electrolyte material according to the present embodiment is usually a mixture of α-type Li ₃ N and β-type Li ₃ N. The diffraction peak present at the diffraction angle 2θ = 32.0 ± 0.4 ° is considered to be a diffraction peak derived from β-type Li ₃ N. This β-type Li ₃ N has a honeycomb structure formed by stacking LiN layers, and this honeycomb structure is considered to affect the improvement of lithium ion conductivity.
That is, having a diffraction peak at a diffraction angle 2θ = 32.0 ± 0.4 °, or the value of _I C / _{I A} is not less than the lower limit Li-P-O-N type inorganic solid electrolyte material This is considered to mean that a honeycomb structure derived from β-type Li ₃ N exists, and it is considered that a higher lithium ion conductivity is expressed by such a honeycomb structure.
Here, the value of the I _{C /} I _A is, for example, be increased by increasing the molar ratio of Li-P-O-N-based inorganic solid the molar ratio and N / P of Li / P in the electrolyte material Is possible.

In the Li—P—O—N-based inorganic solid electrolyte material according to the present embodiment, Li—P—O— by the AC 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 lithium ion conductivity of the N-based inorganic solid electrolyte material is preferably 1.5 × 10 ⁻¹⁰ S · cm ⁻¹ or more, more preferably 1.0 × 10 ⁻⁹ S · cm ⁻¹ or more, and further preferably 1 0.0 × 10 ⁻⁸ S · cm ⁻¹ or more, even more preferably 1.0 × 10 ⁻⁷ S · cm ⁻¹ or more, and even more preferably 1.0 × 10 ⁻⁶ S · cm ⁻¹ or more, further More preferably, it is 2.0 × 10 ⁻⁶ S · cm ⁻¹ or more, and particularly preferably 1.0 × 10 ⁻⁵ S · cm ⁻¹ or more.
When the lithium ion conductivity of the Li—P—O—N-based inorganic solid electrolyte material according to this embodiment is equal to or higher than the lower limit, a lithium ion battery that is more excellent in battery characteristics can be obtained.

The shape of the Li—P—O—N inorganic solid electrolyte material according to the present embodiment is particulate.
The Li—P—O—N-based inorganic solid electrolyte material according to the present embodiment is not particularly limited, but the average particle size d ₅₀ in the weight-based particle size distribution by the laser diffraction scattering type particle size distribution measurement method is preferably 1 μm or more and 50 μm or less. More preferably, they are 2 micrometers or more and 40 micrometers or less, More preferably, they are 3 micrometers or more and 35 micrometers or less.
The Li-P-O-N-based inorganic solid electrolyte average particle size d ₅₀ of the material to be in the above range, while maintaining good handling properties, further improve the lithium ion conductivity of the resulting solid electrolyte film Can be made.

The Li—P—O—N inorganic solid electrolyte material according to the present embodiment is preferably excellent in electrochemical stability. More specifically, in the Li—P—O—N-based inorganic solid electrolyte material according to the present embodiment, Li— measured at a temperature of 25 ° C., a sweep voltage range of 0 to 5 V, and a voltage sweep rate of 5 mV / sec. The maximum value of the oxidative decomposition current of the P—O—N-based inorganic solid electrolyte material is preferably 0.50 μA or less, more preferably 0.20 μA or less, and further preferably 0.10 μA or less, It is particularly preferable that it is 0.05 μA or less.
When the maximum value of the oxidative decomposition current of the Li—P—O—N inorganic solid electrolyte material is not more than the above upper limit value, the oxidative decomposition of the Li—P—O—N inorganic solid electrolyte material in the lithium ion battery is performed. Since it can suppress, it is preferable.
The lower limit value of the maximum value of the oxidative decomposition current of the Li—P—O—N inorganic solid electrolyte material is not particularly limited, and is, for example, 0.0001 μA or more.

In the Li—P—O—N inorganic solid electrolyte material according to the present embodiment, 150 mg of particulate Li—P—O—N inorganic solid electrolyte material is pressure-molded into a pellet having a diameter of 9.5 mm at a pressure of 270 MPa. when, it is preferable that the density of the pellets consisting of Li-P-O-N-based inorganic solid electrolyte material is less than 1.00 g / cm ³ exceeds 1.70 g / cm ³ according to the present embodiment, 1.01 g / more preferably cm ³ or more 1.55 g / cm ³ or less, and more preferably not more than 1.02 g / cm ³ or more 1.45 g / cm ^3.
It is preferable for the density to be in the above range because the adhesion between Li—P—O—N-based inorganic solid electrolyte materials is improved and the lithium ion conductivity is improved.
As for the density of the pellet made of the Li—P—O—N-based inorganic solid electrolyte material according to the present embodiment, for example, the molar ratio of Li / P, the molar ratio of O / P, the molar ratio of N / P, etc. are appropriate. By controlling to, it can be controlled within the above range.
Here, the density can be calculated by dividing the mass (g) of the pellet by the volume (cm ³ ) obtained from the external dimensions of the pellet.

The Li—P—O—N-based inorganic solid electrolyte material according to this embodiment can be used for any application that requires lithium ion conductivity. Among these, the Li—P—O—N inorganic solid electrolyte material according to the present embodiment is preferably used for a lithium ion battery. More specifically, it is used for a positive electrode active material layer, a negative electrode active material layer, an electrolyte layer and the like in a lithium ion battery. Furthermore, the Li—P—O—N-based inorganic solid electrolyte material according to the present embodiment is suitably used for a positive electrode active material layer, a negative electrode active material layer, a solid electrolyte layer, and the like constituting an all solid-state lithium ion battery, It is particularly preferably used for a solid electrolyte layer constituting an all solid-state lithium ion battery.
As an example of the all solid-state type lithium ion battery to which the Li—P—O—N inorganic solid electrolyte material according to the present embodiment is applied, a positive electrode, a solid electrolyte layer, and a negative electrode are stacked in this order. Can be mentioned.

[Method for producing Li-P-O-N-based inorganic solid electrolyte material]
It continues and demonstrates the manufacturing method of the Li-P-O-N type inorganic solid electrolyte material which concerns on this embodiment.
The Li—P—O—N inorganic solid electrolyte material according to the present embodiment can be obtained, for example, by vitrifying the mixture A containing lithium phosphate and lithium nitride as raw materials. Further, as a raw material, a combination of lithium oxide, phosphorus oxide and lithium nitride can be used.
The manufacturing method of the Li—P—O—N based inorganic solid electrolyte material according to the present embodiment does not require a process such as a sputtering method or melting and casting of raw materials, so that it is excellent in manufacturing cost and productivity and practical. Therefore, it is preferable.

First, a mixture A containing raw materials such as lithium phosphate and lithium nitride at a specific ratio is prepared. Here, the mixing ratio of the raw materials in the mixture A is adjusted so that the obtained Li—P—O—N-based inorganic solid electrolyte material has a desired composition ratio.
The method of mixing each raw material is not particularly limited as long as each raw material can be mixed uniformly. For example, a ball mill, a bead mill, a vibration mill, a blow mill, a mixer (pug mixer, ribbon mixer, tumbler mixer, drum) Mixer, V-type mixer, etc.), kneader, biaxial kneader, airflow pulverizer and the like.
Mixing conditions such as agitation speed, processing time, temperature, reaction pressure, and gravitational acceleration applied to the mixture can be appropriately determined depending on the amount of the mixture processed.

Next, the mixture A is vitrified.
The method for vitrifying the mixture A is not particularly limited as long as it is a method capable of vitrifying the mixture A. For example, it can be performed by mechanochemical treatment, a melt quenching method, or the like.
Among these, it is preferable to carry out by mechanochemical treatment. This is because processing at room temperature is possible, and the manufacturing process can be simplified. The mechanochemical treatment may be a dry mechanochemical treatment or a wet mechanochemical treatment.
When mechanochemical treatment is used, each raw material can be mixed while being pulverized into fine particles, so that the contact area of each raw material can be increased. Thereby, since reaction of each raw material can be accelerated | stimulated, the Li-P-ON-type inorganic solid electrolyte material which concerns on this embodiment can be obtained still more efficiently.

  Here, the mechanochemical treatment is a method of vitrification while applying mechanical energy such as shearing force, collision force or centrifugal force to the object to be mixed. Vitrification by mechanochemical treatment includes ball mills, bead mills, vibration mills, turbo mills, mechano-fusions, disk mills, roll mills, and other grinding / dispersing machines; Rotating / striking pulverizers composed of a combination of (shear stress) and impact (compressive stress); high-pressure type grinding rolls; and the like. Among these, a ball mill and a bead mill are preferable, and a ball mill is particularly preferable from the viewpoint that very high impact energy can be efficiently generated. In addition, from the viewpoint of excellent continuous productivity, a roll mill; a rotary and impact crushing device consisting of a combination of rotation (shear stress) and impact (compression stress) represented by rock drills, vibratory drills, impact drivers, etc. A high-pressure type grinding roll;

  Further, when the mixture A is vitrified, an aprotic organic solvent such as hexane, toluene, or xylene may be added, and the raw materials may be dispersed in the solvent.

The mechanochemical treatment is preferably performed in an inert atmosphere. Thereby, reaction with the mixture A, water vapor | steam, oxygen, etc. can be suppressed.
In addition, the inactive atmosphere is a vacuum atmosphere or an inert gas atmosphere. In the non-active atmosphere, the dew point is preferably −50 ° C. or lower, and more preferably −60 ° C. or lower in order to avoid contact with moisture. The “inert gas atmosphere” means an atmosphere of an inert gas such as argon gas, helium gas, nitrogen gas or the like. These inert gases are preferably as high as possible in order to prevent impurities from entering the product. 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. However, the inert gas is purged, and a constant amount of inert gas is continuously introduced. Methods and the like.

The mixing conditions such as the rotational speed, processing time, temperature, reaction pressure, and gravitational acceleration applied to the mixture A when the mixture A is vitrified can be appropriately determined depending on the type of the mixture A and the processing amount. In general, the faster the rotation speed, the faster the glass production rate, and the longer the treatment time, the higher the conversion to glass.
Normally, when X-ray diffraction analysis using CuKα rays as a radiation source is performed, if the diffraction peak derived from the raw material in the mixture A disappears or decreases, the mixture A is vitrified, and the desired Li—P— It can be determined that an O—N-based inorganic solid electrolyte material is obtained.

Here, in the step of vitrifying the mixture A, the maximum diffraction intensity at the diffraction angle 2θ = 15.0 ± 0.1 ° in the spectrum obtained by X-ray diffraction using CuKα rays as the radiation source is determined as the background intensity. and I _a, when a diffraction intensity of a diffraction peak at the position of the diffraction angle 2θ = 33.0 ± 0.5 ° was _{I B,} preferably the value of _I B / I _a 50 or less, more preferably 30 Hereinafter, it is preferable to perform vitrification until it becomes more preferably 20 or less, and particularly preferably 15 or less.
The I B _/ I _A With more than the above upper limit, it is possible to further improve the lithium ion conductivity of the Li-P-O-N-based inorganic solid electrolyte material. Furthermore, when such a Li—P—O—N-based inorganic solid electrolyte material is used, a lithium ion battery more excellent in input / output characteristics can be obtained.
Here, the maximum diffraction intensity _{I A} at the position of the diffraction angle 2θ = 15.0 ± 0.1 °, a diffraction intensity of the reference, at the position of the diffraction angle 2θ = 33.0 ± 0.5 ° diffraction The peak is a diffraction peak derived from lithium phosphate.
_Therefore, I B / _{I A} represents an indication of the Li-P-O-N-based content of the lithium phosphate inorganic solid electrolyte material. As I B _/ I _A is small, the process proceeds vitrification, means that less amount of lithium phosphate is a raw material.
Since lithium phosphate has low lithium ion conductivity, it is considered that the lithium ion conductivity of the Li—P—O—N inorganic solid electrolyte material is improved as the lithium phosphate content is reduced.
Although the lower limit is not particularly limited because preferably as the I B _/ I _A small as possible, for example, 0.01 or more.

Further, in the step of vitrifying the mixture A, the lithium of the Li—P—O—N-based inorganic solid electrolyte material by the AC impedance method under the measurement conditions of 27.0 ° C., the applied voltage of 10 mV, and the measurement frequency range of 0.1 Hz to 7 MHz. The ionic conductivity is preferably 1.5 × 10 ⁻¹⁰ S · cm ⁻¹ or more, more preferably 1.0 × 10 ⁻⁹ S · cm ⁻¹ or more, further preferably 1.0 × 10 ⁻⁸ S · cm. cm ⁻¹ or more, even more preferably 1.0 × 10 ⁻⁷ S · cm ⁻¹ or more, even more preferably 1.0 × 10 ⁻⁶ S · cm ⁻¹ or more, and even more preferably 2.0 × 10 It is preferable to perform vitrification treatment until ⁻⁶ S · cm ⁻¹ or more, particularly preferably 1.0 × 10 ⁻⁵ S · cm ⁻¹ or more. Thereby, a Li—P—O—N-based inorganic solid electrolyte material more excellent in lithium ion conductivity can be obtained.

Moreover, in the manufacturing method of the Li—P—O—N-based inorganic solid electrolyte material according to the present embodiment, before the step of vitrifying the mixture A, the step of crystallizing the mixture A by heating the mixture A It is preferable to do further.
That is, it is preferable to perform the vitrification step on the crystallized mixture A.
By performing the crystallization process of the mixture A before the vitrification process of the mixture A, the vitrification process of the mixture A can be greatly shortened. As a result, the Li—P—O—N-based inorganic solid electrolyte material It is possible to further reduce the manufacturing time.

It does not specifically limit as temperature at the time of heating the said mixture A, According to the Li-P-O-N type inorganic solid electrolyte material to produce | generate, it can set suitably.
For example, the heating temperature is preferably in the range of 200 ° C. or higher and 400 ° C. or lower, and more preferably in the range of 220 ° C. or higher and 300 ° C. or lower.

  The time for heating the mixture A is not particularly limited as long as the mixture A can be crystallized, but is, for example, in the range of 1 minute to 24 hours, preferably 0.1 hours or more. 10 hours or less. The heating method is not particularly limited, and examples thereof include a method using a firing furnace. In addition, conditions, such as temperature and time at the time of such a heating, can be suitably adjusted in order to optimize the characteristic of the Li-P-O-N type inorganic solid electrolyte material which concerns on this embodiment.

  Whether or not the mixture A has crystallized can be determined by whether or not a new crystal peak has been generated in a spectrum obtained by X-ray diffraction using CuKα rays as a radiation source, for example.

Moreover, by heating the obtained glass state Li—P—O—N inorganic solid electrolyte material, at least a part of the Li—P—O—N inorganic solid electrolyte material is crystallized to form a glass ceramic state. It is good also as a Li-P-O-N type inorganic solid electrolyte material.
The temperature for heating the Li-P-O-N inorganic solid electrolyte material in the glass state is preferably in the range of 200 ° C. or higher and 500 ° C. or lower, and in the range of 220 ° C. or higher and 350 ° C. or lower. It is more preferable.
The time for heating the Li-P-O-N inorganic solid electrolyte material in the glass state is not particularly limited as long as the desired Li-P-O-N inorganic solid electrolyte material is obtained. For example, it is in the range of 1 minute to 24 hours, preferably 0.5 hours to 3 hours. The heating method is not particularly limited, and examples thereof include a method using a firing furnace. In addition, conditions, such as temperature and time at the time of such a heating, can be suitably adjusted in order to optimize the characteristic of the Li-P-O-N type inorganic solid electrolyte material which concerns on this embodiment.

The heating of the Li-P-O-N inorganic solid electrolyte material in the glass state is preferably performed, for example, in an inert gas atmosphere. Thereby, deterioration of a Li-P-O-N type inorganic solid electrolyte material can be prevented.
Examples of the inert gas when heating the glass-like Li—P—O—N inorganic solid electrolyte material include argon gas, helium gas, nitrogen gas, and the like. These inert gases are preferably higher in purity in order to prevent impurities from entering the product, and in order to avoid contact with moisture, the dew point is preferably −50 ° C. or lower, and −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. However, the inert gas is purged, and a constant amount of inert gas is continuously introduced. Methods and the like.

In the method for producing the Li—P—O—N based inorganic solid electrolyte material according to the present embodiment, the obtained Li—P—O—N based inorganic solid electrolyte material is pulverized, classified, or granulated as necessary. You may perform further the process to do. For example, a Li—P—O—N-based inorganic solid electrolyte material having a desired particle size can be obtained by making fine particles by pulverization and then adjusting the particle size by classification or granulation. It does not specifically limit as said grinding | pulverization method, Well-known grinding | pulverization methods, such as a mixer, airflow grinding | pulverization, a mortar, a rotary mill, a coffee mill, can be used. Moreover, it does not specifically limit as said classification method, Well-known methods, such as a sieve, can be used.
These pulverization or classification are preferably performed in an inert gas atmosphere or a vacuum atmosphere from the viewpoint that contact with moisture in the air can be prevented.

  In order to obtain the Li—P—O—N based inorganic solid electrolyte material according to the present embodiment, it is important to appropriately adjust each of the above steps. However, the manufacturing method of the Li—P—O—N-based inorganic solid electrolyte material according to the present embodiment is not limited to the above method, and by appropriately adjusting various conditions, the present embodiment can be used. Such a Li—P—O—N inorganic solid electrolyte material can be obtained.

[Solid electrolyte]
Next, the solid electrolyte according to the present embodiment will be described. The solid electrolyte according to the present embodiment includes the Li—P—O—N based inorganic solid electrolyte material according to the present embodiment.
And although the solid electrolyte which concerns on this embodiment is not specifically limited, As a component other than the Li-P-O-N type inorganic solid electrolyte material which concerns on this embodiment, for example in the range which does not impair the objective of this invention, A solid electrolyte material of a type different from the Li—P—O—N based inorganic solid electrolyte material according to the present embodiment described above may be included.

  The solid electrolyte according to the present embodiment may include a different type of solid electrolyte material from the Li—P—O—N inorganic solid electrolyte material according to the present embodiment described above. The type of solid electrolyte material different from the Li—P—O—N-based inorganic solid electrolyte material according to the present embodiment is not particularly limited as long as it has ion conductivity and insulating properties. What is used for a battery can be used. Examples thereof include inorganic solid electrolyte materials such as sulfide-based inorganic solid electrolyte materials, oxide-based inorganic solid electrolyte materials, and other lithium-based inorganic solid electrolyte materials; organic solid electrolyte materials such as polymer electrolytes.

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, and 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 Examples include S—P ₂ S ₅ —P ₄ S ₃ material. These may be used individually by 1 type and may be used in combination of 2 or more type.
Among these, Li ₂ S—P ₂ S ₅ material is preferable because it is excellent in lithium ion conductivity and has stability that does not cause decomposition in a wide voltage range. Here, for example, the Li ₂ S—P ₂ S ₅ material is an inorganic material obtained by chemically reacting an inorganic composition containing at least Li ₂ S (lithium sulfide) and P ₂ S ₅ with each other by mechanical treatment. Means material.
Here, in this embodiment, lithium polysulfide is also included in lithium sulfide.

Examples of the oxide-based inorganic solid electrolyte material include NASICON types such as LiTi ₂ (PO ₄ ) ₃ , LiZr ₂ (PO ₄ ) ₃ , LiGe ₂ (PO ₄ ) ₃ , and (La _{0.5 + x} Li _{0.5 −3x} ) TiO _{3 and} other perovskite types, Li ₂ O—P ₂ O ₅ materials, Li ₂ O—P ₂ O ₅ —Li ₃ N materials, 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, and the like. It is done.
Furthermore, glass ceramics obtained by precipitating these inorganic solid electrolyte crystals can also be used as the inorganic solid electrolyte material.

As the organic solid electrolyte material, for example, a polymer electrolyte such as a dry polymer electrolyte or a gel electrolyte can be used.
As a polymer electrolyte, what is generally used for a lithium ion battery can be used.

[Solid electrolyte membrane]
Next, the solid electrolyte membrane according to the present embodiment will be described.
The solid electrolyte membrane according to the present embodiment includes a solid electrolyte including the Li—P—O—N-based inorganic solid electrolyte material according to the present embodiment as a main component.

The solid electrolyte membrane according to the present embodiment is used for, for example, a solid electrolyte layer constituting an all solid-state lithium ion battery.
As an example of the all-solid-state lithium ion battery to which the solid electrolyte membrane according to the present embodiment is applied, a battery in which a positive electrode, a solid electrolyte layer, and a negative electrode are stacked in this order can be given. In this case, the solid electrolyte layer is constituted by a solid electrolyte membrane.

  The average thickness of the solid electrolyte membrane according to this embodiment is preferably 5 μm or more and 500 μm or less, more preferably 10 μm or more and 200 μm or less, and further preferably 20 μm or more and 100 μm or less. When the average thickness of the solid electrolyte membrane is equal to or more than the lower limit value, it is possible to further suppress the occurrence of a lack of solid electrolyte and the occurrence of cracks on the surface of the solid electrolyte membrane. Moreover, the impedance of a solid electrolyte membrane can be further reduced as the average thickness of the said solid electrolyte membrane is below the said upper limit. As a result, the battery characteristics of the obtained all solid-state lithium ion battery can be further improved.

The solid electrolyte membrane according to the present embodiment is preferably a particulate solid electrolyte pressure-molded body containing the Li—P—O—N inorganic solid electrolyte material according to the present embodiment described above. That is, it is preferable to pressurize the particulate solid electrolyte to obtain a solid electrolyte membrane having a certain strength due to the anchor effect between the solid electrolyte materials.
By using a pressure-molded body, the solid electrolytes are bonded to each other, and the strength of the obtained solid electrolyte membrane is further increased. As a result, it is possible to further suppress the occurrence of solid electrolyte loss and cracks on the surface of the solid electrolyte membrane.

The content of the Li—P—O—N-based inorganic solid electrolyte material according to this embodiment in the solid electrolyte membrane according to this embodiment is preferably 50% when the entire solid electrolyte membrane is 100% by mass. It is at least 60% by mass, more preferably at least 60% by mass, even more preferably at least 70% by mass, even more preferably at least 80% by mass, particularly preferably at least 90% by mass. Thereby, the contact property between solid electrolytes is improved and the interfacial contact resistance of a solid electrolyte membrane can be reduced. As a result, the lithium ion conductivity of the solid electrolyte membrane can be further improved. And the battery characteristic of the all-solid-state type lithium ion battery obtained can be further improved by using such a solid electrolyte membrane excellent in lithium ion conductivity.
The upper limit of the content of the Li—P—O—N-based inorganic solid electrolyte material according to the present embodiment in the solid electrolyte membrane according to the present embodiment is not particularly limited, and is, for example, 100% by mass or less.

  The planar shape of the solid electrolyte membrane is not particularly limited, and can be appropriately selected according to the shape of the electrode and the current collector. For example, the solid electrolyte membrane can be rectangular.

Further, the solid electrolyte membrane according to this embodiment may contain a binder resin, but the content of the binder resin is preferably less than 0.5% by mass when the entire solid electrolyte membrane is 100% by mass. More preferably, it is 0.1 mass% or less, More preferably, it is 0.05 mass% or less, More preferably, it is 0.01 mass% or less. Further, the solid electrolyte membrane according to this embodiment is still more preferably substantially free of binder resin, and most preferably free of binder resin.
Thereby, the contact property between solid electrolytes is improved and the interfacial contact resistance of a solid electrolyte membrane can be reduced. As a result, the lithium ion conductivity of the solid electrolyte membrane can be further improved. And the battery characteristic of the obtained all-solid-type lithium ion battery can be improved by using the solid electrolyte membrane excellent in such lithium ion conductivity.
Note that “substantially free of binder resin” means that it may be contained to the extent that the effects of the present embodiment are not impaired. Further, when an adhesive resin layer is provided between the solid electrolyte layer and the positive electrode or the negative electrode, the adhesive resin derived from the adhesive resin layer present in the vicinity of the interface between the solid electrolyte layer and the adhesive resin layer is expressed as “solid electrolyte It is removed from the “binder resin in the film”.

  The binder resin refers to a binder generally used for lithium ion batteries in order to bind between inorganic solid electrolyte materials. For example, polyvinyl alcohol, polyacrylic acid, carboxymethyl cellulose, polytetrafluoro Examples include ethylene, polyvinylidene fluoride, styrene / butadiene rubber, and polyimide.

The solid electrolyte membrane according to the present embodiment is obtained by, for example, depositing a particulate solid electrolyte in a film shape on the cavity surface of a mold or on a substrate surface, and then pressurizing the solid electrolyte deposited in the film shape. Can be obtained.
The method of pressurizing the solid electrolyte is not particularly limited. For example, when a particulate solid electrolyte is deposited on the cavity surface of the mold, pressing with a mold and a pressing mold, the particulate solid electrolyte is applied to the substrate surface. In the case of depositing on the top, a press using a die and a pressing die, a roll press, a flat plate press or the like can be used.
The pressure for pressurizing the solid electrolyte is, for example, 10 MPa or more and 500 MPa or less.

If necessary, the inorganic solid electrolyte deposited in a film shape may be pressurized and heated. If heating and pressurization are performed, the solid electrolytes are fused and bonded, and the strength of the obtained solid electrolyte membrane is further increased. As a result, it is possible to further suppress the occurrence of solid electrolyte loss and cracks on the surface of the solid electrolyte membrane.
The temperature which heats a solid electrolyte is 40 degreeC or more and 500 degrees C or less, for example.

[Lithium ion battery]
FIG. 1 is a cross-sectional view showing an example of the structure of a lithium ion battery 100 according to an embodiment of the present invention.
The lithium ion battery 100 according to the present embodiment includes, for example, a positive electrode 110 including a positive electrode active material layer 101, an electrolyte layer 120, and a negative electrode 130 including a negative electrode active material layer 103. At least one of the positive electrode active material layer 101, the negative electrode active material layer 103, and the electrolyte layer 120 contains the Li—P—O—N inorganic solid electrolyte material according to the present embodiment. Moreover, it is preferable that all of the positive electrode active material layer 101, the negative electrode active material layer 103, and the electrolyte layer 120 contain the Li—P—O—N-based inorganic solid electrolyte material according to the present embodiment. Note that in this embodiment, a layer containing a positive electrode active material is referred to as a positive electrode active material layer 101, and a positive electrode active material layer 101 formed on a current collector 105 is referred to as a positive electrode 110 unless otherwise specified. A layer including the negative electrode active material is referred to as a negative electrode active material layer 103, and a layer in which the negative electrode active material layer 103 is formed over the current collector 105 is referred to as a negative electrode 130. Note that the positive electrode 110 and the negative electrode 130 may include the current collector 105 or may not include the current collector 105 as necessary.
The shape of the lithium ion battery 100 according to the present embodiment is not particularly limited, and examples thereof include a cylindrical shape, a coin shape, a square shape, a film shape, and other arbitrary shapes.

  The lithium ion battery 100 according to the present embodiment is generally manufactured according to a known method. For example, by stacking the positive electrode 110, the electrolyte layer 120, and the negative electrode 130 into a cylindrical shape, a coin shape, a square shape, a film shape, or any other shape, and encapsulating a non-aqueous electrolyte as necessary Produced.

(Positive electrode)
The positive electrode 110 is not particularly limited, and those commonly used for lithium ion batteries can be used. The positive electrode 110 is not particularly limited, but can be generally manufactured according to a known method. For example, it can be obtained by forming a positive electrode active material layer 101 containing a positive electrode active material on the surface of a current collector 105 such as an aluminum foil.
The thickness and density of the positive electrode active material layer 101 are not particularly limited because they are appropriately determined according to the intended use of the battery, and can be generally set according to known information.

The positive electrode active material layer 101 includes a positive electrode active material.
The positive electrode active material is not particularly limited, and generally known materials can be used. 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.)) ), Lithium-manganese-nickel oxide (LiNi _1/3 Mn _1/3 Co _1/3 O ₂ ), olivine-type lithium phosphorus oxide (LiFePO ₄ ) and other complex oxides; polyaniline, polypyrrole and other highly conductive materials _{molecule; Li 2 S, CuS, Li} -CuS _{compounds, TiS 2, FeS, MoS 2} , Li-MoS compounds, Li-TiS compounds, Li-V-S compounds, Li-FeS compound Sulfide-based positive electrode active materials such as acetylene black impregnated with sulfur, porous carbon impregnated with sulfur, sulfur and carbon mixed powder, etc. And materials; and the like can be used. These positive electrode active materials may be used individually by 1 type, and may be used in combination of 2 or more type.
Among these, from the viewpoint of having a higher discharge capacity density and more excellent 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 is preferable. One or more selected from compounds are more preferred.

Here, the Li—Mo—S compound contains Li, Mo, and S as constituent elements, and an inorganic composition containing molybdenum sulfide and lithium sulfide, which are usually raw materials, is chemically treated by mechanical treatment. It can be obtained by reacting.
Further, the Li—Ti—S compound contains Li, Ti, and S as constituent elements, and an inorganic composition containing titanium sulfide and lithium sulfide, which are usually raw materials, is chemically reacted with each other by mechanical treatment. Can be obtained.
The Li-VS compound contains Li, V, and S as constituent elements, and an inorganic composition containing vanadium sulfide and lithium sulfide, which are usually raw materials, is chemically reacted with each other by mechanical treatment. Can be obtained.

  Although the positive electrode active material layer 101 is not particularly limited, the component other than the positive electrode active material may include, for example, one or more materials selected from a binder resin, a thickener, a conductive additive, a solid electrolyte material, and the like. . Hereinafter, each material will be described.

The positive electrode active material layer 101 may include a binder resin having a role of binding the positive electrode active materials to each other and the positive electrode active material and the current collector 105.
The binder resin of the present embodiment is not particularly limited as long as it is a normal binder resin that can be used in a lithium ion battery. For example, polyvinyl alcohol, polyacrylic acid, carboxymethyl cellulose, polytetrafluoroethylene, polyvinylidene fluoride, styrene / butadiene System rubber, polyimide and the like. These binders may be used alone or in combination of two or more.

  The positive electrode active material layer 101 may contain a thickener from the viewpoint of ensuring the fluidity of the slurry suitable for application. The thickener is not particularly limited as long as it is a normal thickener usable for lithium ion batteries. For example, cellulose polymers such as carboxymethylcellulose, methylcellulose, hydroxypropylcellulose, and ammonium salts and alkali metal salts thereof. Examples thereof include water-soluble polymers such as polycarboxylic acid, polyethylene oxide, polyvinyl pyrrolidone, polyacrylate, and polyvinyl alcohol. These thickeners may be used individually by 1 type, and may be used in combination of 2 or more types.

  From the viewpoint of improving the conductivity of the positive electrode 110, the positive electrode active material layer 101 may include a conductive additive. The conductive auxiliary agent is not particularly limited as long as it is a normal conductive auxiliary agent that can be used for a lithium ion battery, and examples thereof include carbon blacks such as acetylene black and ketjen black, and carbon materials such as vapor grown carbon fibers. .

  The positive electrode according to the present embodiment may include a solid electrolyte including the Li—P—O—N-based inorganic solid electrolyte material according to the present embodiment described above, or the Li—P—O—N according to the present embodiment. A solid electrolyte containing a different type of solid electrolyte material from the inorganic inorganic solid electrolyte material may be included. The type of solid electrolyte material different from the Li—P—O—N-based inorganic solid electrolyte material according to the present embodiment is not particularly limited as long as it has ion conductivity and insulating properties. What is used for a battery can be used. Examples thereof include inorganic solid electrolyte materials such as sulfide-based inorganic solid electrolyte materials, oxide-based inorganic solid electrolyte materials, and other lithium-based inorganic solid electrolyte materials; organic solid electrolyte materials such as polymer electrolytes. More specifically, the inorganic solid electrolyte materials mentioned in the description of the solid electrolyte according to this embodiment can be used.

  The mixing ratio of various materials in the positive electrode active material layer 101 is not particularly limited because it is appropriately determined according to the intended use of the battery and the like, and can be generally set according to known information.

(Negative electrode)
The negative electrode 130 is not specifically limited, What is generally used for the lithium ion battery can be used. The negative electrode 130 is not particularly limited, but can be generally manufactured according to a known method. For example, it can be obtained by forming a negative electrode active material layer 103 containing a negative electrode active material on the surface of a current collector 105 such as copper.
The thickness and density of the negative electrode active material layer 103 are not particularly limited because they are appropriately determined according to the intended use of the battery and the like, and can generally be set according to known information.

The negative electrode active material layer 103 includes a negative electrode active material.
The negative electrode active material is not particularly limited as long as it is a normal negative electrode active material that can be used for a negative electrode of a lithium ion battery. For example, natural graphite, artificial graphite, resin charcoal, carbon fiber, activated carbon, hard carbon, soft carbon Carbonaceous materials such as lithium, lithium alloys, tin, tin alloys, silicon, silicon alloys, gallium, gallium alloys, indium, indium alloys, aluminum, aluminum alloys, etc .; polyacene, polyacetylene, polypyrrole, etc. A conductive polymer of lithium titanium composite oxide (for example, Li ₄ Ti ₅ O ₁₂ ) and the like. These negative electrode active materials may be used individually by 1 type, and may be used in combination of 2 or more type.

Although the negative electrode active material layer 103 is not particularly limited, the component other than the negative electrode active material may include, for example, one or more materials selected from a binder resin, a thickener, a conductive additive, a solid electrolyte material, and the like. . These materials are not particularly limited, and examples thereof include the same materials as those used for the positive electrode 110 described above.
The mixing ratio of various materials in the negative electrode active material layer 103 is not particularly limited because it is appropriately determined according to the intended use of the battery and the like, and can generally be set according to known information.

(Electrolyte layer)
Next, the electrolyte layer 120 will be described. The electrolyte layer 120 is a layer formed between the positive electrode active material layer 101 and the negative electrode active material layer 103.
Examples of the electrolyte layer 120 include those in which a separator is impregnated with a nonaqueous electrolytic solution, and solid electrolyte layers containing a solid electrolyte.

  The separator of the present embodiment is not particularly limited as long as it has a function of electrically insulating the positive electrode 110 and the negative electrode 130 and transmitting lithium ions. For example, a porous film can be used.

  A microporous polymer film is preferably used as the porous film, and examples of the material include polyolefin, polyimide, polyvinylidene fluoride, and polyester. In particular, a porous polyolefin film is preferable, and specific examples include a porous polyethylene film and a porous polypropylene film.

The non-aqueous electrolyte is obtained by dissolving an electrolyte in a solvent.
As the electrolyte, any known lithium salt can be used, and may be selected according to the type of active material. For _{example, LiClO 4, LiBF 6, LiPF} 6, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF 6, LiSbF 6, LiB 10 Cl 10, LiAlCl 4, LiCl, LiBr, LiB (C 2 H 5) 4, CF 3 Examples include SO ₃ Li, CH ₃ SO ₃ Li, LiCF ₃ SO ₃ , LiC ₄ F ₉ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, and lower fatty acid carboxylate lithium.

  The solvent for dissolving the electrolyte is not particularly limited as long as it is usually used as a liquid for dissolving the electrolyte. Ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), dimethyl carbonate (DMC) Carbonates such as diethyl carbonate (DEC), methyl ethyl carbonate (MEC), vinylene carbonate (VC); lactones such as γ-butyrolactone and γ-valerolactone; trimethoxymethane, 1,2-dimethoxyethane, diethyl ether , Ethers such as 2-ethoxyethane, tetrahydrofuran and 2-methyltetrahydrofuran; sulfoxides such as dimethyl sulfoxide; oxolanes such as 1,3-dioxolane and 4-methyl-1,3-dioxolane; Nitrogens such as ril, nitromethane, formamide, dimethylformamide; organic acid esters such as methyl formate, methyl acetate, ethyl acetate, butyl acetate, methyl propionate, ethyl propionate; phosphate triesters and diglymes; Sulfolanes such as sulfolane and methylsulfolane; oxazolidinones such as 3-methyl-2-oxazolidinone; sultones such as 1,3-propane sultone, 1,4-butane sultone and naphtha sultone; These may be used individually by 1 type and may be used in combination of 2 or more type.

The solid electrolyte layer according to the present embodiment is a layer formed between the positive electrode active material layer 101 and the negative electrode active material layer 103, and is a layer formed of a solid electrolyte containing a solid electrolyte material. The solid electrolyte contained in the solid electrolyte layer is not particularly limited as long as it has lithium ion conductivity. In the present embodiment, the Li—P—O—N inorganic solid according to the present embodiment is used. A solid electrolyte containing an electrolyte material is preferable.
The content of the solid electrolyte in the solid electrolyte layer of the present embodiment is not particularly limited as long as a desired insulating property is obtained. For example, the content is in the range of 10% by volume to 100% by volume, In the range of 50% by volume to 100% by volume. In particular, in the present embodiment, it is preferable that the solid electrolyte layer is composed only of a solid electrolyte containing the Li—P—O—N based inorganic solid electrolyte material according to the present embodiment.

  Moreover, the solid electrolyte layer of the present embodiment may contain a binder resin. By containing the binder resin, a flexible solid electrolyte layer can be obtained. Examples of the binder resin include fluorine-containing binders such as polytetrafluoroethylene and polyvinylidene fluoride. The thickness of the solid electrolyte layer is, for example, preferably in the range of 0.1 μm to 1000 μm, and more preferably in the range of 0.1 μm to 300 μm.

As mentioned above, although embodiment of this invention was described, these are illustrations of this invention and various structures other than the above are also employable.
It should be noted that the present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.

  Hereinafter, although an example and a comparative example explain the present invention, the present invention is not limited to these.

[1] Measuring Method First, measuring methods in the following examples and comparative examples will be described.

(1) Particle size distribution The particle size distribution of the inorganic solid electrolyte materials used in Examples and Comparative Examples was measured by a laser diffraction method using a laser diffraction / scattering particle size distribution measuring apparatus (manufactured by Malvern, Mastersizer 3000). From the measurement results, the particle size (D ₅₀ , average particle size) at 50% accumulation in the weight-based cumulative distribution was determined for the inorganic solid electrolyte material.

(2) Measurement of composition ratio Using an ICP emission spectroscopic analyzer (manufactured by Seiko Instruments Inc., SPS3000), it was measured by ICP emission spectroscopic analysis, and in the inorganic solid electrolyte materials obtained in Examples and Comparative Examples The mass% of Li, P, and O was calculated | required, respectively, and the molar ratio of each element was calculated based on it, respectively. Moreover, since the amount of N was confirmed from the semi-quantitative analysis using energy dispersive X-ray analysis (EDX), almost all of the charged N remained in the material. Therefore, the charged amount was used.

(3) X-ray diffraction analysis Diffraction spectra of the inorganic solid electrolyte materials obtained in Examples and Comparative Examples were obtained by X-ray diffraction analysis using an X-ray diffraction apparatus (RINT2000, manufactured by Rigaku Corporation). Note that CuKα rays were used as the radiation source. Here, the maximum diffraction intensity at the position of the diffraction angle 2θ = 15.0 ± 0.1 ° and background intensity _{I A,} the diffraction of the diffraction peak at the position of the diffraction angle 2θ = 33.0 ± 0.5 ° the intensity and _{I B,} the diffraction intensity of the diffraction peak at the position of the diffraction angle 2θ = 32.0 ± 0.4 ° and _{I C,} respectively obtained with I B / _{I a} and _I C / _{I a.}

(4) Measurement of lithium ion conductivity Lithium ion conductivity was measured by an alternating current impedance method for the inorganic solid electrolyte materials obtained in the examples and comparative examples.
Lithium ion conductivity was measured using a potentiostat / galvanostat SP-300 manufactured by Biologic. The size of the sample is 9.5 mm in diameter, 1.2 to 2.0 mm in thickness, the measurement conditions are applied voltage 10 mV, measurement temperature 27.0 ° C., measurement frequency range 0.1 Hz to 7 MHz, and the electrode is Li foil. .
Here, as a sample for measuring lithium ion conductivity, a pressing apparatus was used to press 150 mg of the powdered inorganic solid electrolyte material obtained in Examples and Comparative Examples at 270 MPa for 10 minutes, and a diameter of 9. A plate-like inorganic solid electrolyte material having a thickness of 5 mm and a thickness of 1.2 to 2.0 mm was used.

(5) Measurement of maximum value of oxidative decomposition current Using a pressing device, 120 to 150 mg of powdered inorganic solid electrolyte material obtained in Examples and Comparative Examples was pressed at 270 MPa for 10 minutes, diameter 9.5 mm, thickness A plate-like inorganic solid electrolyte material (pellet) having a thickness of 1.3 mm was obtained. Subsequently, Li foil as a reference electrode / counter electrode was press-pressed under a condition of 18 MPa for 10 minutes on one surface of the obtained pellet, and SUS314 foil was adhered as a working electrode to the other surface.
Next, using the potentiostat / galvanostat SP-300 manufactured by Biologic Co., Ltd., the maximum oxidative decomposition current of the inorganic solid electrolyte material under the conditions of a temperature of 25 ° C., a sweep voltage range of 0 to 5 V, and a voltage sweep rate of 5 mV / second The value was determined.

(6) Measurement of density Using a pressing device, 150 mg of the powdered inorganic solid electrolyte material obtained in the examples and comparative examples was pressed at 270 MPa for 10 minutes, a diameter of 9.5 mm, and a thickness of 1.2 to 2. A 0 mm plate-like inorganic solid electrolyte material (pellet) was obtained. Next, the density was calculated by dividing the mass (g) of the obtained pellet by the volume (cm ³ ) determined from the external dimensions of the pellet.

[2] Production of inorganic solid electrolyte material <Example 1>
A Li—P—O—N-based inorganic solid electrolyte material was prepared by the following procedure.
Li ₃ PO ₄ (manufactured by Wako Pure Chemical Industries) and Li ₃ N were used as raw materials. Li ₃ N (mixture of α-type and β-type) was prepared by the following procedure.
First, in a nitrogen atmosphere glove box, a stainless steel sword mountain was used for Li foil (manufactured by Honjo Metal Co., Ltd., purity 99.8%, thickness 0.5 mm), and a number of holes having a diameter of 1 mm or less were formed. The Li foil began to turn black-purple from the hole, and all the Li foil changed to black-purple Li ₃ N by leaving it at room temperature for 24 hours. Li ₃ N was pulverized with an agate mortar and then sieved with a stainless steel sieve, and a powder of 75 μm or less was recovered and used as a raw material for the solid electrolyte material.
Subsequently, each raw material (Li ₃ PO ₄ and Li ₃ N) was precisely weighed so that Li / P, O / P and N / P had the values shown in Table 1 in an argon glove box. Mix in agate mortar for minutes. Next, 2 g of the mixed powder was weighed, put into an alumina pot (inner volume 45 mL) together with 18 φ10 mm zirconia balls, and pulverized and mixed for 15 hours in a planetary ball mill (rotation 800 rpm, revolution 400 rpm). Next, after the powder after grinding and mixing on the inner wall of the pot and the ball is scraped off, the powder is again put in the same pot together with the ball and ground and mixed for 15 hours by a planetary ball mill (rotation 800 rpm, revolution 400 rpm), and Li—PO— An N-based inorganic solid electrolyte material was obtained.
Each evaluation was performed about the obtained Li-P-O-N type inorganic solid electrolyte material. The obtained results are shown in Table 1.

<Examples 2 to 12>
Li-P in the same manner as in Example 1 except that the ratio of each raw material (Li ₃ PO ₄ and Li ₃ N) was changed so that Li / P, O / P, and N / P had the values shown in Table 1. Each of —O—N-based inorganic solid electrolyte materials was prepared and evaluated. The obtained results are shown in Table 1, respectively.

<Comparative Example 1>
An inorganic solid electrolyte material was produced in the same manner as in Example 1 except that Li ₃ N was not used as a raw material, and each evaluation was performed. The obtained results are shown in Table 1.

<Comparative example 2>
An inorganic solid electrolyte material was prepared and evaluated in the same manner as in Example 1 except that Li ₃ PO ₄ was not used as a raw material. The obtained results are shown in Table 1.

The Li—P—O—N inorganic solid electrolyte materials of Examples 1 to 12 were excellent in lithium ion conductivity and electrochemical stability. In addition, the Li—P—O—N inorganic solid electrolyte materials of Examples 1 to 12 have diffraction peaks derived from Li ₃ PO ₄ and Li ₃ N as raw materials as shown in the X-ray diffraction spectrum (FIG. 2). From the decrease or disappearance, it was confirmed that vitrification was progressing.
Here, in FIG. 2 and FIG. 3, as reference data, an X-ray diffraction spectrum of Li ₃ N (α-type and β-type) and Li ₃ PO ₄ before vitrification (extracted from the International Center for Diffraction Data database) ) And an X-ray diffraction spectrum of Li _2.88 PO _3.73 N _0.14 sputtering film (extracted from the International Center for Diffraction Data database).
On the other hand, the inorganic solid electrolyte material of Comparative Example 1 was inferior in lithium ion conductivity. In addition, although the inorganic solid electrolyte material of Comparative Example 2 was excellent in lithium ion conductivity, the maximum value of the oxidative decomposition current was high, the decomposition start temperature was as low as 0.75 V, and the electrochemical stability was inferior. There wasn't.

DESCRIPTION OF SYMBOLS 100 Lithium ion battery 101 Positive electrode active material layer 103 Negative electrode active material layer 105 Current collector 110 Positive electrode 120 Electrolyte layer 130 Negative electrode

Claims (18)

A particulate Li—P—O—N inorganic solid electrolyte material having lithium ion conductivity and containing Li, P, O and N as constituent elements,
The molar ratio (Li / P) of the content of Li to the content of P in the Li-P-O-N-based inorganic solid electrolyte material is 3.5 or more and 100.0 or less, and the content of P The molar ratio (O / P) of the content of O to the amount is 2.0 or more and 6.0 or less, and the molar ratio (N / P) of the content of N to the content of P is 0.1. A Li—P—O—N-based inorganic solid electrolyte material of 31.0 or less. In the Li-P-ON-based inorganic solid electrolyte material according to claim 1,
In the spectrum obtained by X-ray diffraction using a CuKα ray the highest diffraction intensity at the position of the diffraction angle 2θ = 15.0 ± 0.1 ° and background intensity _{I A} as a radiation source, a diffraction angle 2 [Theta] = 33.0 ± _A Li—P—O—N-based inorganic solid electrolyte material having a value of I _B / IA of 50 or less, where I _B is the diffraction intensity of a diffraction peak present at a position of 0.5 °. In the Li-P-O-N-based inorganic solid electrolyte material according to claim 1 or 2,
A Li—P—O—N inorganic solid electrolyte material having a diffraction peak at a diffraction angle 2θ = 32.0 ± 0.4 ° in a spectrum obtained by X-ray diffraction using CuKα rays as a radiation source. In the Li-P-ON-based inorganic solid electrolyte material according to claim 3,
In the spectrum obtained by X-ray diffraction using a CuKα ray the highest diffraction intensity at the position of the diffraction angle 2θ = 15.0 ± 0.1 ° and background intensity _{I A} as a radiation source, a diffraction angle 2 [Theta] = 32.0 ± _A Li—P—O—N-based inorganic solid electrolyte material having a value of I _C / IA of 2.0 or more, where I _C is the diffraction intensity of the diffraction peak present at a position of 0.4 °. In the Li-P-O-N-based inorganic solid electrolyte material according to any one of claims 1 to 4,
Li-P-ON-based inorganic solid electrolyte material containing no S as a constituent element. In the Li-P-O-N-based inorganic solid electrolyte material according to any one of claims 1 to 5,
The maximum value of the oxidative decomposition current of the Li—P—O—N-based inorganic solid electrolyte material measured at a temperature of 25 ° C., a sweep voltage range of 0 to 5 V, and a voltage sweep rate of 5 mV / sec is 0.50 μA or less. A certain Li—P—O—N inorganic solid electrolyte material. In the Li-P-O-N-based inorganic solid electrolyte material according to any one of claims 1 to 6,
In weight particle size distribution by a laser diffraction scattering particle size distribution measurement method, the Li-P-O-N-based inorganic solid electrolyte average particle size _{d 50} of material is 1μm or more 50μm or less Li-P-O-N-based inorganic Solid electrolyte material. In the Li-P-O-N-based inorganic solid electrolyte material according to any one of claims 1 to 7,
Li-P-O-N based inorganic solid electrolyte material used for lithium ion batteries. In the Li-P-O-N-based inorganic solid electrolyte material according to any one of claims 1 to 8,
27.0 ° C., the applied voltage 10 mV, a measurement frequency range wherein by the AC impedance method in the measurement conditions 0.1Hz~7MHz Li-P-O-N-based inorganic solid electrolyte material Li ion conductivity 1.5 × 10 the ^- Li-P-O-N-based inorganic solid electrolyte material of ¹⁰ S · cm ⁻¹ or more. In the Li-P-O-N-based inorganic solid electrolyte material according to any one of claims 1 to 9,
When 150 mg of the particulate Li—P—O—N-based inorganic solid electrolyte material was pressed into a pellet having a diameter of 9.5 mm at a pressure of 270 MPa,
The Li-P-O-N-based inorganic solid density of the pellets made of the electrolyte material is 1.00 g / cm ³ exceeds 1.70 g / cm ³ or less Li-P-O-N-based inorganic solid electrolyte material.   The solid electrolyte containing the Li-P-O-N type inorganic solid electrolyte material as described in any one of Claims 1 thru | or 10.   A solid electrolyte membrane comprising the solid electrolyte according to claim 11 as a main component. The solid electrolyte membrane according to claim 12,
A solid electrolyte membrane which is a pressure-formed body of the particulate solid electrolyte. The solid electrolyte membrane according to claim 12 or 13,
A solid electrolyte membrane in which the content of the binder resin in the solid electrolyte membrane is less than 0.5 mass% when the entire solid electrolyte membrane is 100 mass%. The solid electrolyte membrane according to any one of claims 12 to 14,
A solid electrolyte membrane in which the content of the Li—P—O—N-based inorganic solid electrolyte material in the solid electrolyte membrane is 50% by mass or more when the entire solid electrolyte membrane is 100% by mass. A lithium ion battery comprising a positive electrode including a positive electrode active material layer, an electrolyte layer, and a negative electrode including a negative electrode active material layer,
11. The lithium ion in which at least one of the positive electrode active material layer, the electrolyte layer, and the negative electrode active material layer contains the Li—P—O—N-based inorganic solid electrolyte material according to claim 1. battery. A manufacturing method for manufacturing the Li-P-O-N-based inorganic solid electrolyte material according to any one of claims 1 to 10,
The manufacturing method of the Li-P-ON-type inorganic solid electrolyte material including the process of vitrifying the mixture A containing lithium phosphate and lithium nitride. In the manufacturing method of the Li-P-O-N type inorganic solid electrolyte material according to claim 17,
In the step of vitrifying the mixture A,
The manufacturing method of the Li-P-ON-type inorganic solid electrolyte material which vitrifies the said mixture A by carrying out mechanical milling process.

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