JP7563373B2 - Solid electrolyte, method for producing solid electrolyte, and all-solid-state battery - Google Patents

Description

This disclosure relates to a solid electrolyte, a method for producing a solid electrolyte, and an all-solid-state battery.

All-solid-state batteries are batteries that have a solid electrolyte layer between a positive electrode layer and a negative electrode layer, and have the advantage that safety devices can be simplified more easily than liquid batteries that have an electrolyte solution that contains a flammable organic solvent. Organic solid electrolytes and inorganic solid electrolytes are known as solid electrolytes used in the solid electrolyte layer.

For example, Patent Document 1 discloses an electrolyte composition that contains, as a solid electrolyte, a matrix that contains an organic cation and a boron cluster anion, and a metal salt that contains a metal cation and an anion.

JP 2020-194777 A

The battery performance of an all-solid-state battery is greatly affected by the ionic conductivity of the solid electrolyte. Therefore, a solid electrolyte with good ionic conductivity is desired. This disclosure has been made in consideration of the above-mentioned circumstances, and has as its main object to provide a solid electrolyte with good ionic conductivity.

In order to solve the above problems, the present disclosure provides a solid electrolyte having a matrix containing a pyrrolidinium-based organic cation and a boron cluster anion, and a metal salt containing a metal cation and an anion, the solid electrolyte having peak A appearing at 2θ=15.7°±0.5° and peak B appearing at 2θ=18.2°±0.5° in an X-ray diffraction measurement using CuKα radiation, and the intensity of peak A or peak B is the greatest among all peaks observed in the X-ray diffraction measurement.

The present disclosure also provides a solid electrolyte having a matrix containing a pyrrolidinium-based organic cation and a boron cluster anion, and a metal salt containing a metal cation and an _anion , the solid electrolyte having peak A appearing at a position of 2θ=15.7°±0.5° and peak B appearing at a position of 2θ=18.2°±0.5° in an X-ray diffraction measurement using CuKα radiation, the solid electrolyte satisfying at least one of the following conditions (i ₎ and ( _ii ):
Condition (i): (I _A -I _S )/I _S is greater than 2.69.
Condition (ii): (I _B −I _S )/I _S is greater than 0.73.

According to the present disclosure, the solid electrolyte has good ionic conductivity because it has the specified peak A and peak B.

In the above disclosure, the intensity of the peak A or the intensity of the peak B may be the greatest among all peaks observed in the above X-ray diffraction measurement.

In the above disclosure, the (I _A -I _S )/I _S may be 7.74 or greater.

In the above disclosure, the (I _B −I _S )/I _S may be 3.16 or greater.

In the above disclosure, the anion in the metal salt may be a boron cluster anion.

The present disclosure also provides a method for producing the above-mentioned solid electrolyte, the method comprising the steps of: preparing a precursor containing the matrix containing the pyrrolidinium-based organic cation and the boron cluster anion, and the metal salt containing the metal cation and the anion; heating the precursor at a temperature equal to or higher than the melting temperature of the matrix to obtain a molten precursor; and quenching the molten precursor to obtain the solid electrolyte by quenching and solidifying it.

According to the present disclosure, by including a rapid cooling process, a solid electrolyte with good ionic conductivity can be produced.

The present disclosure also provides an all-solid-state battery having a positive electrode active material layer, a negative electrode active material layer, and a solid electrolyte layer disposed between the positive electrode active material layer and the negative electrode active material layer, in which at least one of the positive electrode active material layer, the negative electrode active material layer, and the solid electrolyte layer contains the above-mentioned solid electrolyte.

According to the present disclosure, at least one of the positive electrode active material layer, the negative electrode active material layer, and the solid electrolyte layer contains the above-mentioned solid electrolyte, resulting in an all-solid-state battery with good input and output characteristics.

The present disclosure has the effect of providing a solid electrolyte with good ionic conductivity.

FIG. 2 is a flow diagram showing an example of a method for producing a solid electrolyte according to the present disclosure. FIG. 1 is a schematic cross-sectional view showing an example of an all-solid-state battery according to the present disclosure. 1 shows the results of X-ray diffraction measurement in Example 1 and Comparative Example 1.

The solid electrolyte, the method for producing the solid electrolyte, and the all-solid-state battery in this disclosure are described in detail below.

A. Solid electrolyte The solid electrolyte of the present disclosure is a solid electrolyte having a matrix containing a pyrrolidinium-based organic cation and a boron cluster anion, and a metal salt containing a metal cation and an anion, and the solid electrolyte has a peak A appearing at 2θ=15.7°±0.5° and a peak B appearing at 2θ=18.2°±0.5° in an X-ray diffraction measurement using CuKα radiation. In addition, the solid electrolyte of the present disclosure preferably has the largest intensity of the peak A or the peak B among all peaks observed in the X-ray diffraction measurement. In addition, the solid electrolyte of the present disclosure preferably satisfies a predetermined condition when the intensity of the peak A is I _A , the intensity of the peak B is I _B , and the intensity at the reference position is I _S.

According to the present disclosure, the solid electrolyte has good ionic conductivity because it has the specified peak A and peak B.

As described above, a solid electrolyte with good ionic conductivity is desired. The present inventors have conducted extensive research into an electrolyte composition (solid electrolyte) containing a matrix containing an organic cation and a boron cluster anion, and a metal salt containing a metal cation and an anion, and have found that a solid electrolyte with a novel crystal phase can be obtained by a specified manufacturing method, and that this solid electrolyte has good ionic conductivity.

In an X-ray diffraction measurement using CuKα radiation, the solid electrolyte in the present disclosure has peak A appearing at 2θ=15.7°±0.5° and peak B appearing at 2θ=18.2°±0.5°. The positions of peak A and peak B may vary within a range of ±0.3°, or within a range of ±0.1°.

In the present disclosure, it is preferable that the intensity of peak A or the intensity of peak B is the greatest among all peaks observed in the X-ray diffraction measurement.

In addition, in the present disclosure, when the intensity of peak A is I _A , the intensity of peak B is I _B , and the intensity at the reference position is I _S , it is preferable to satisfy at least one of the following conditions (i) and (ii):
Condition (i): (I _A -I _S )/I _S is greater than 2.69.
Condition (ii): (I _B −I _S )/I _S is greater than 0.73.
In this disclosure, the value calculated by (I _A −I _S )/I _S may be referred to as standard value 1, and the value calculated by (I _B −I _S )/I _S may be referred to as standard value 2.

In this disclosure, the "reference position" refers to a position where no peak is observed in X-ray diffraction measurement. The reference position is preferably a position that is -2° or more away from the position of the peak observed at the lowest angle side, or a position that is +2° or more away from the position of the peak observed at the highest angle side. A specific example of the reference position is 2θ = 12.0°.

(I _A -I _S )/I _S may be 3.00 or more, 5.00 or more, 7.00 or more, or 7.74 or more. On the other hand, the upper limit of (I _A -I _S )/I _S is not particularly limited, but is, for example, 13.00 or less. Also, (I _B -I _S )/I _S may be 1.00 or more, 2.00 or more, 3.00 or more, or 3.16 or more. On the other hand, the upper limit of (I _B -I _S )/I _S is not particularly limited, but is, for example, 8.00 or less.

Furthermore, I _A and I _B may be the same or different. I _A and I _B being "the same" refers to the case where the ratio of I _B to I _A (I _B /I _A ) is 0.95 or more and 1.05 or less. When I _A and I _B are different, I _B /I _A is, for example, 0.5 or more, may be 0.7 or more, or may be 0.9 or more. On the other hand, I _B /I _A is, for example, 1.5 or less, may be 1.3 or less, or may be 1.1 or less.

In addition, the solid electrolyte in the present disclosure may have only peak A and peak B in an X-ray diffraction measurement using CuKα radiation, or may have peaks other than peak A and peak B. In the latter case, the position of the peak other than peak A and peak B may be, for example, at least one of 2θ = 15.0 ± 0.5°, 16.8° ± 0.5°, and 17.4° ± 0.5°. These peak positions may each vary within a range of ± 0.3°. In the present disclosure, the peak obtained at the above position may be referred to as peak X.

In addition, the solid electrolyte of the present disclosure preferably does not have a peak Y at 2θ=16.1±0.5° in X-ray diffraction measurement. Peak Y is a peak other than the above-mentioned peaks A, B, and X. "Does not have a peak Y" means that, when the intensity of a peak other than peaks A, B, and X at 2θ=16.1±0.5° is _IY , _IY / _IA is 0.1 or less, or _IY / _IB is 0.1 or less.

1. Matrix The matrix in the present disclosure contains a pyrrolidinium-based organic cation and a boron cluster anion. The solid electrolyte may contain one type of matrix or may contain two or more types of matrices.

The pyrrolidinium-based organic cation is typically an organic cation having a pyrrolidinium skeleton, and is preferably represented by the following structure.

In the formula, R and R′ each independently represent a substituent belonging to any one of the following groups:
Group (i): linear, branched or cyclic alkyl or fluoroalkyl groups having 1 to 8 carbon atoms.
Group (ii): an aryl group or a fluoroaryl group having 6 to 9 carbon atoms.
Group (iii): linear, branched or cyclic alkoxy or fluoroalkoxy groups having 1 to 8 carbon atoms.
Group (iv): an aryloxy group or a fluoroaryloxy group having 6 to 9 carbon atoms.
Group (v): amino group.
Group (vi): Substituents having two or more moieties defined by any two or more of groups (i) to (v).

Specific examples of pyrrolidinium-based organic cations include N-methyl-N-propylpyrrolidinium (Pyr13), N-methyl-N-(2-methoxyethyl)-pyrrolidinium (Pyr12ol), N-methyl-N-ethylpyrrolidinium (Pyr12), and N-methyl-N-butylpyrrolidinium (Pyr14).

Boron cluster anion refers to any of the following anionic forms: borane, which has 6 to 12 boron atoms and a net charge of -2; carborane, which has one carbon atom and 5 to 11 boron atoms in the cluster structure and a net charge of -1; and carborane, which has two carbon atoms and 4 to 10 boron atoms in the cluster structure and a net charge of -1 or -2.

The boron cluster anion may be unsubstituted, and may have only hydrogen atoms in addition to boron atoms and carbon atoms. The boron cluster anion may also have hydrogen atoms substituted. In this case, the hydrogen atoms may be replaced with at least one of a halogen atom and an organic substituent. The number of substituted hydrogen atoms may be one or more. The type of halogen atom and the type of organic substituent may each be one or more.

The boron cluster anion can be represented, for example, by any one of the following general formulas (i) to (v).
General formula (i): [B _y H _(y-z-i) R ¹ _z X _i ] ^2-
General formula (ii): [CB _(y-1) H _(y-zi) R ¹ _z X _i ] ^-
General formula (iii): [C ₂ B _(y-2) H _(y-t-j-1) R ¹ _t X _j ] ^-
General formula (iv): [C ₂ B _(y-3) H _(y-t-j) R ¹ _t X _j ] ^-
General formula (v): [C ₂ B _(y-3) H _(y-t-j-1) R ¹ _t X _j ] ^2-
In the formula, y is an integer satisfying 6≦y≦12, z+i is an integer satisfying 0≦z+i≦y, t+j is an integer satisfying 0≦t+j≦y−1, and X is at least one of F, Cl, Br, and I. In addition, R ¹ is an organic substituent or hydrogen.

Examples of boron cluster anions include [B ₆ H ₆ ] ²⁻ , [B ₁₂ H ₁₂ ] ²⁻ , [CB ₉ H ₁₀ ] ⁻ , [CB ₁₁ H ₁₂ ] ⁻ , and [C ₂ B ₁₀ H ₁₁ ] ⁻ . The boron cluster anion may have a so-called closo structure.

2. Metal Salt The metal salt in the present disclosure contains a metal cation and an anion. The solid electrolyte may contain one type of metal salt or may contain two or more types of metal salts.

Metal cations include, for example, alkali metal cations such as Li ⁺ and Na ⁺ , and alkaline earth metal cations such as Mg2 ⁺ and Ca2 ⁺ .

The anion in the metal salt may or may not be a boron cluster anion as described above, such as (fluorosulfonyl)imide (FSI), bis(trifluoromethanesulfonyl)imide (TFSI), hexafluorophosphate (PF ₆ ), and tetrafluoroborate (BF ₄ ).

3. Solid Electrolyte The solid electrolyte in the present disclosure has a matrix containing a pyrrolidinium-based organic cation and a boron cluster anion, and a metal salt containing a metal cation and an anion.

The solid electrolyte has a pyrrolidinium-based organic cation and a boron cluster anion as cations. The ratio of the pyrrolidinium-based organic cation to the total of the pyrrolidinium-based organic cation and the metal cation is, for example, 1 mol% to 50 mol%, and may be 5 mol% to 30 mol%. The solid electrolyte preferably contains at least N-methyl-N-butylpyrrolidinium (Pyr14) and Li as cations. That is, it is preferable to use a combination of a matrix containing Pyr14 as the pyrrolidinium-based organic cation and a metal salt containing Li as the metal cation.

The solid electrolyte has at least a boron cluster anion as an anion. The anion in the solid electrolyte may be only a boron cluster anion. The solid electrolyte may have one, two or more kinds of boron cluster anions as an anion. The solid electrolyte preferably contains at least one of [B ₆ H ₆ ] ^2- , [B ₁₂ H ₁₂ ] ^2- , [CB ₉ H ₁₀ ] ^- , [CB ₁₁ H ₁₂ ] ^- and [C ₂ B ₁₀ H ₁₁ ] ^- as an anion. Among them, the solid electrolyte preferably contains at least [CB ₉ H ₁₀ ] ^- and [CB ₁₁ H ₁₂ ] ^- as an anion. For example, when the solid electrolyte contains [CB ₉ H ₁₀ ] ^- and [CB ₁₁ H ₁₂ ] ^- as anions, the ratio of [CB ₉ H ₁₀ ] - to the total of [CB ₉ H ₁₀ ] ^- and [CB ₁₁ H ₁₂ ^{] -} is, for example, 30 mol % or more and 90 mol % or less, or may be 40 mol % or more and 80 mol % or less, or may be 50 mol % or more and 70 mol % or less.

The solid electrolyte of the present disclosure preferably has high ionic conductivity. The ionic conductivity at 25°C is, for example, 0.3 mS/cm or more, may be 0.6 mS/cm or more, or may be 0.9 mS/cm or more. On the other hand, the ionic conductivity at 25°C is, for example, 7 mS/cm or less, may be 5 mS/cm or less, 3 mS/cm or less, 2 mS/cm or less, or may be 1.2 mS/cm or less.

The shape of the solid electrolyte may be, for example, particulate. The particle diameter (D50) of the solid electrolyte is, for example, 0.1 μm or more and 50 μm or less. The particle diameter D50 refers to the cumulative 50% particle diameter in the volume-based particle diameter distribution measured by a laser diffraction particle size distribution measuring device. In addition, it is preferable that the elastic modulus of the solid electrolyte is low. The elastic modulus is, for example, less than 10 GPa, may be less than 1 GPa, or may be less than 0.5 GPa. In addition, the solid electrolyte may be a single-phase material having a single crystal phase, or may be a multi-phase material having multiple crystal phases.

B. Manufacturing method of solid electrolyte Fig. 1 is a flow diagram showing an example of a manufacturing method of a solid electrolyte in the present disclosure. As shown in Fig. 1, the manufacturing method of a solid electrolyte in the present disclosure includes a preparation step of preparing a precursor containing a matrix containing a pyrrolidinium-based organic cation and a boron cluster anion, and a metal salt containing a metal cation and an anion, a heating step of heating the precursor at a temperature equal to or higher than the melting temperature of the matrix to obtain a melt of the precursor, and a quenching step of quenching and solidifying the melt to obtain the solid electrolyte.

According to the present disclosure, by including a rapid cooling process, a solid electrolyte with good ionic conductivity can be produced.

1. Preparation Step The preparation step is a step of preparing a precursor containing a matrix containing a pyrrolidinium-based organic cation and a boron cluster anion, and a metal salt containing a metal cation and an anion.

In the preparation step, the precursors may be purchased or prepared by oneself. In the latter case, for example, the above-mentioned matrix material and metal salt material can be mixed to prepare the material. It is preferable to appropriately adjust the ratio of each material in consideration of the composition of the desired solid electrolyte.

2. Heating Step The heating step is a step of heating the precursor to a temperature equal to or higher than the melting temperature of the matrix to obtain a molten precursor.

The heating temperature in the heating step is not limited as long as it is equal to or higher than the melting point of the matrix, but can be, for example, 150°C or higher and 200°C or lower. In addition, it is preferable that the time of the heating step (heating time) is short. The heating time is, for example, 12 hours or less, may be 9 hours or less, or may be 6 hours or less. On the other hand, the heating time is, for example, 2 hours or more, and may be 4 hours or more.

3. Quenching Step The quenching step is a step of rapidly cooling the molten material to solidify it, thereby obtaining the above-mentioned solid electrolyte.

In the rapid cooling method, a method is usually used in which the molten material is directly or indirectly brought into contact with a refrigerant. The difference between the temperature of the molten material and the temperature of the refrigerant is, for example, 80°C or more, or may be 100°C or more, or may be 120°C or more. For example, when the temperature of the molten material is 160°C and the molten material is exposed to room temperature (refrigerant temperature 25°C), the temperature difference between the two is 135°C.

The cooling rate in the quenching step is, for example, 3°C/min or more, may be 10°C/min or more, or may be 100°C/min or more. Here, the cooling rate refers to the average cooling rate obtained by dividing the difference between the temperature of the molten material before quenching and the temperature of the solid electrolyte after quenching (for example, 50°C) by the quenching time (for example, the time until 50°C is reached). If the cooling rate is too slow, it is presumed that a crystalline phase that cannot contribute to ion conduction will be formed. In addition, the quenching may be performed to a temperature at which the molten material solidifies, but may be, for example, cooled to 50°C or less, or may be cooled to room temperature (25°C). The quenching time in the quenching step is, for example, 1 second or more and 45 minutes or less. Specific quenching methods include, for example, a method of exposing the molten material to room temperature, a method of contacting a container containing the molten material with a liquid such as water or ice water, and a method of contacting the molten material with a rotating metal roll.

C. All-solid-state battery Fig. 2 is a schematic cross-sectional view showing an example of an all-solid-state battery in the present disclosure. The all-solid-state battery 10 shown in Fig. 2 has a positive electrode active material layer 1, a negative electrode active material layer 2, and a solid electrolyte layer 3 arranged between the positive electrode active material layer 1 and the negative electrode active material layer 2, and at least one of the positive electrode active material layer 1, the negative electrode active material layer 2, and the solid electrolyte layer 3 contains the above-mentioned solid electrolyte. In addition, the all-solid-state battery 10 has a positive electrode current collector 4 that collects current from the positive electrode active material layer 1, and a negative electrode current collector 5 that collects current from the negative electrode active material layer 2.

According to the present disclosure, at least one of the positive electrode active material layer, the negative electrode active material layer, and the solid electrolyte layer contains the above-mentioned solid electrolyte, resulting in an all-solid-state battery with good input and output characteristics.

1. Positive Electrode Active Material Layer The positive electrode active material layer in the present disclosure contains at least a positive electrode active material, and may contain at least one of a solid electrolyte, a conductive material, and a binder, as necessary.

Examples of the positive electrode active material include oxide active materials, such as rock salt layered active materials such as LiCoO ₂ and LiNi _1/3 Co _1/3 Mn _1/3 O ₂ , spinel active materials such as LiMn ₂ O ₄ , and olivine active materials such as LiFePO ₄ .

As the solid electrolyte, a conventional solid electrolyte used in an all-solid-state battery may be used, but the solid electrolyte in the present disclosure described above is preferable. As the conductive material, for example, a carbon material such as acetylene black (AB) may be used. As the binder, for example, a rubber-based binder or a fluoride-based binder may be used. The thickness of the positive electrode active material layer is, for example, 0.1 μm or more and 1000 μm or less.

2. Negative Electrode Active Material Layer The negative electrode active material layer contains at least a negative electrode active material, and may contain at least one of a solid electrolyte, a conductive material, and a binder, as necessary.

Examples of negative electrode active materials include metal active materials (simple or alloys) such as Si, Sn, Li, In, and Al, carbon active materials such as graphite, and oxide active materials such as lithium titanate.

As the solid electrolyte, a conventional solid electrolyte used in an all-solid-state battery may be used, but the solid electrolyte in the present disclosure described above is preferable. The conductive material and binder are the same as those described in "1. Positive electrode active material layer", so the description here is omitted. The thickness of the negative electrode active material layer is, for example, 0.1 μm or more and 1000 μm or less.

3. Solid Electrolyte Layer The solid electrolyte layer contains at least a solid electrolyte, and may contain a binder as necessary.

As the solid electrolyte, a conventional solid electrolyte used in an all-solid-state battery may be used, but the solid electrolyte in the present disclosure described above is preferable. The binder is the same as that described in "1. Positive electrode active material layer", so the description here is omitted. The thickness of the solid electrolyte layer is, for example, 0.1 μm or more and 1000 μm or less.

4. Positive electrode current collector and negative electrode current collector The all-solid-state battery in the present disclosure usually has a positive electrode current collector that collects the positive electrode active material layer and a negative electrode current collector that collects the negative electrode active material layer. The positive electrode current collector and the negative electrode current collector are not particularly limited, and may be conventionally known positive electrode current collectors and negative electrode current collectors used in all-solid-state batteries. Examples of the positive electrode current collector include Al and SUS. Examples of the negative electrode current collector include Cu and Ni. The thickness and shape of the positive electrode current collector and the negative electrode current collector can be appropriately selected depending on the application of the all-solid-state battery.

5. All-solid-state battery The all-solid-state battery in the present disclosure is typically an all-solid-state lithium-ion secondary battery. The use of the all-solid-state battery is not particularly limited, but examples thereof include power sources for vehicles such as hybrid electric vehicles (HEVs), electric vehicles (BEVs), gasoline-powered vehicles, and diesel-powered vehicles. In particular, it is preferable to use the all-solid-state battery as a driving power source for hybrid electric vehicles or electric vehicles. In addition, the all-solid-state battery in the present disclosure may be used as a power source for moving objects other than vehicles (e.g., railways, ships, and aircraft), and may be used as a power source for electrical products such as information processing devices.

This disclosure is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and anything that has substantially the same configuration as the technical ideas described in the claims of this disclosure and has similar effects is included within the technical scope of this disclosure.

[Example 1]
(Synthesis of solid electrolyte)
Pyr14CB ₉ H ₁₀ was prepared as a matrix containing an organic cation and a boron cluster anion. LiCB ₉ H ₁₀ and LiCB ₁₁ H ₁₂ were prepared as metal salts. These were weighed and mixed so that the molar ratio of Pyr14CB ₉ H ₁₀ : LiCB ₉ H ₁₀ : LiCB ₁₁ H ₁₂ = 2: 4: 4 was obtained. Next, the mixture was heated and mixed at 160 ° C. for 6 hours. After 30 minutes, the melt was removed from the heating device and rapidly cooled to room temperature. This resulted in the synthesis of a solid electrolyte.

(Preparation of evaluation cells)
The synthesized solid electrolyte was formed into a pellet at a pressure of 20 kN, which was then sandwiched between Al foils to prepare an evaluation cell.

[Comparative Example 1]
A solid electrolyte and an evaluation cell were prepared in the same manner as in Example 1, except that the heating and mixing time was 15 hours, after which the heating device was turned off and the mixture was gradually cooled to room temperature on the heating device over a period of 2 hours.

[evaluation]
(X-ray diffraction measurement)
X-ray diffraction (XRD) measurement using CuKα radiation was performed on the solid electrolytes obtained in Example 1 and Comparative Example 1. The results of the XRD measurement are shown in FIG. 3. From the results of the XRD measurement, standard value 1 ((I _A -I _S )/I _S ) and standard value 2 ((I _B -I _S )/I _S ) were calculated. The results are shown in Table 1. As I _S , the intensity at 2θ=12.0° was used.

(Ionic Conductivity Measurement)
The ionic conductivity at 25° C. was calculated by an AC impedance method for the evaluation cells obtained in Example 1 and Comparative Example 1. The results are shown in Table 1.

As shown in Table 1, the ionic conductivity of Example 1 was higher than that of Comparative Example 1. Also, as shown in Table 1 and FIG. 3, in Example 1, both standard value 1 and standard value 2 were higher than those of Comparative Example 1. Also, as shown in FIG. 3, in Example 1, the intensity of peak A obtained at 2θ = 15.7° was the highest, and the intensity of peak B obtained at 2θ = 18.2° was the next highest. On the other hand, in Comparative Example 1, the intensity of the peak obtained at 2θ = 17.4° was the highest. Also, in Comparative Example 1, a peak that was not observed in Example 1 was observed near 2θ = 16.1°. From this result, it was confirmed that the solid electrolyte of Example 1 has a different crystal phase from the solid electrolyte of Comparative Example 1.

1...Positive electrode active material layer 2...Negative electrode active material layer 3...Solid electrolyte layer 4...Positive electrode current collector 5...Negative electrode current collector 10...All-solid-state battery

Claims (8)

a matrix containing a pyrrolidinium-based organic cation and a boron cluster anion;
and a metal salt containing a metal cation and an anion,
In an X-ray diffraction measurement using CuKα radiation, the solid electrolyte has a peak A appearing at 2θ=15.7°±0.5° and a peak B appearing at 2θ=18.2°±0.5°,
A solid electrolyte, wherein, among all peaks observed in the X-ray diffraction measurement, the intensity of the peak A is the largest and the intensity of the peak B is the second largest . a matrix containing a pyrrolidinium-based organic cation and a boron cluster anion;
and a metal salt containing a metal cation and an anion,
In an X-ray diffraction measurement using CuKα radiation, the solid electrolyte has a peak A appearing at 2θ=15.7°±0.5° and a peak B appearing at 2θ=18.2°±0.5°,
A solid electrolyte, which satisfies the following conditions (i) and (ii), where the intensity of the peak A is I _A , the intensity of the peak B is I _B , and the intensity at a reference position is I _S :
Condition (i): (I _A -I _S )/I _S is greater than 2.69.
Condition (ii): (I _B −I _S )/I _S is greater than 0.73. 3. The solid electrolyte according to claim 2, wherein, among all peaks observed in the X-ray diffraction measurement, the intensity of the peak A is the largest and the intensity of the peak B is the second largest . 4. The solid electrolyte according to claim 2, wherein the (I _A -I _S )/I _S is 7.74 or more. The solid electrolyte according to any one of claims 2 to 4, wherein the (I _B -I _S )/I _S is 3.16 or more. The solid electrolyte according to any one of claims 1 to 5, wherein the anion in the metal salt is a boron cluster anion. A method for producing a solid electrolyte according to any one of claims 1 to 6, comprising the steps of:
a preparation step of preparing a precursor containing the matrix containing the pyrrolidinium-based organic cation and the boron cluster anion, and the metal salt containing the metal cation and the anion;
a heating step of heating the precursor at a temperature equal to or higher than the melting temperature of the matrix to obtain a melt of the precursor;
and a quenching step of quenching the molten material to solidify it, thereby obtaining the solid electrolyte. An all-solid-state battery having a positive electrode active material layer, a negative electrode active material layer, and a solid electrolyte layer disposed between the positive electrode active material layer and the negative electrode active material layer,
An all-solid-state battery, wherein at least one of the positive electrode active material layer, the negative electrode active material layer and the solid electrolyte layer contains the solid electrolyte according to any one of claims 1 to 6.