Compound, method for producing same, solid electrolyte, and power storage device

Abstract

A compound that satisfies formula (1). D α M β X 6‑γ A γ …(1) In equation (1), α and β Each is an independent value greater than 0. gamma Values ​​greater than 0 and less than 6, where D is an alkali metal element, M contains elements other than alkali metal elements that become metal cations, X is a halogen element, and A is a group of atoms containing two or more elements that become polyatomic anions.

Description

Technical Field

[0001] [Cross-reference to related applications] This application claims priority based on Japanese Patent Application No. 2024-057325, filed March 29, 2024, and Japanese Patent Application No. 2024-117673, filed July 23, 2024, the entirety of which is incorporated herein by reference.

[0002] This invention relates to compounds and their manufacturing methods, solid electrolytes, and energy storage devices. Background Technology

[0003] As energy storage devices, various secondary batteries such as nickel-metal hydride batteries and lithium-ion batteries, as well as double-layer capacitors, have been put into practical use. Among them, lithium-ion batteries (LIBs) are widely used due to their high energy density and battery capacity.

[0004] Lithium-ion secondary batteries, widely used as energy storage devices, have a negative electrode, a positive electrode, and an electrolyte. They are charged and discharged by moving lithium ions between the two electrodes via the electrolyte. Previously, non-aqueous electrolytes were primarily used. However, because non-aqueous electrolytes contain flammable organic solvents, there are concerns about electrolyte leakage and internal short circuits caused by overcharging or over-discharging. In view of these considerations, research has been conducted on all-solid-state (all-solid-state) lithium-ion secondary batteries that use solid electrolytes with lithium-ion conductivity to replace non-aqueous electrolytes (see, for example, Patent Document 1).

[0005] On the other hand, there are concerns that lithium, which is the raw material for all-solid-state lithium-ion secondary batteries, faces problems such as soaring raw material prices and resource depletion. Therefore, in recent years, research on sodium-ion secondary batteries (SIBs), which use abundant and inexpensive sodium and charge and discharge through the movement of sodium ions, as a post-lithium-ion secondary battery to replace the rare metal lithium, has been advancing in various fields (for example, see Patent Document 2).

[0006] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2023-49975 Patent Document 2: International Publication No. 2019 / 003846 Summary of the Invention

[0007] The technical problem that the invention aims to solve Solid electrolytes with ionic conductivity include sulfide-based, oxide-based, and halogen-based solid electrolytes. Among them, halogen-based solid electrolytes exhibit high ionic conductivity and plastic deformation properties, making them promising candidates for use as electrolyte materials in all-solid-state batteries. However, from the perspective of practical application of all-solid-state batteries, the ionic conductivity of conventional halogen-based solid electrolytes is still insufficient and has room for further improvement. In particular, to achieve high capacity and high output in secondary batteries such as LIBs and SIBs, new solid electrolyte materials exhibiting high ionic conductivity are needed.

[0008] The present invention was made in view of the following circumstances, and one of its objectives is to provide novel halogen compounds exhibiting high ionic conductivity.

[0009] Technical solutions for solving technical problems In order to solve the above-mentioned problems, the inventors conducted in-depth research and discovered that by replacing part of the halogen element in a specific compound having a halogen element as a constituent with an atomic group that is a polyatomic anion containing two or more elements, it is possible to obtain a halogen-based compound exhibiting good ionic conductivity. Specifically, the present invention provides the following compounds, methods for manufacturing the same, solid electrolytes, and energy storage devices.

[0010] [1] A compound that satisfies the following formula (1).

[0011] D α M β X 6-γ A γ …(1) (In formula (1), α and β Each is an independent value greater than 0. c Values ​​greater than 0 and less than 6, where D is an alkali metal element, M contains elements other than alkali metals that become metal cations, X is a halogen element, and A is a group containing two or more elements that become polyatomic anions. [2] According to the compound described in [1], wherein D in the above formula (1) is Na.

[0012] [3] According to the compound described in [1] or [2], wherein the ionic radius of the element other than the alkali metal that becomes a metal cation is set as r. M When [Å], 0.4≤r is satisfied. M ≤0.9.

[0013] [4] The compound according to any one of [1] to [3], wherein M in the above formula (1) contains at least one element selected from Ta, Zr, Hf, Ge, Ga, Sn and Sc.

[0014] [5] The compound according to any one of [1] to [4], wherein A in the above formula (1) has an oxygen atom.

[0015] [6] The compound according to any one of [1] to [5], wherein A in the above formula (1) contains an atomic group that is an inorganic polyatomic anion.

[0016] [7] The compound according to any one of [1] to [6], wherein the ionic radius of A in the above formula (1) is set to r. A When [Å], 0.9≤r is satisfied. A ≤2.7.

[0017] [8] The compound according to any one of [1] to [7], wherein X in the above formula (1) is Cl (chlorine).

[0018] [9] The compound according to any one of [1] to [8], wherein the compound satisfies the following formula (2).

[0019] Na 1+y1+2×(y2)+3×(y3)+z1+2×(z2)+3×(z3) Ta 1-y1-y2-y3 M1 y1 M2 y2 M3 y3 Cl 6-z1-z2-z3 A1 z1 A2 z2 A3 z3 …(2) (In formula (2), y1, y2, y3, z1, z2 and z3 are each independently a value greater than or equal to 0, M1 is an element that becomes a tetravalent metal cation, M2 is an element that becomes a trivalent metal cation, M3 is an element that becomes a divalent metal cation, A1 is a group of atoms containing two or more elements that becomes a divalent polyatomic anion, A2 is a group of atoms containing two or more elements that becomes a trivalent polyatomic anion, and A3 is a group of atoms containing two or more elements that becomes a tetravalent polyatomic anion, satisfying 0 < y1 + y2 + y3 < 1 and 0 < z1 + z2 + z3 < 6.)

[10] The compound according to any one of [1] to [9], wherein the mass fraction of the amorphous phase of the compound is 10% or more.

[0020]

[11] A method for manufacturing a compound, which is a method for manufacturing the compound described in any one of [1] to

[10] , wherein the method for manufacturing the compound comprises: A process of weighing multiple supply components containing one or more of the elements D, M, X and A in the above formula (1) in a manner that satisfies the stoichiometric ratio of the composition shown in the above formula (1); and a process of pulverizing the weighed multiple supply components under cooling based on a cooling medium.

[0021]

[12] A solid electrolyte comprising any one of the compounds described in [1] to

[10] .

[0022]

[13] An energy storage device comprising the solid electrolyte described in

[12] .

[0023] Invention Effects According to the present invention, novel halogen compounds exhibiting high ionic conductivity can be obtained. Furthermore, by using the compounds of the present invention as electrolytes in energy storage devices such as secondary batteries and capacitors, energy storage devices that combine the safety guarantees provided by solidified electrolytes with high ionic conductivity can be obtained. Attached Figure Description

[0024] Figure 1 This is a schematic structural diagram of a grinding processing device equipped with a cooling mechanism based on a cooling medium.

[0025] Figure 2 This is a schematic diagram of the stamping die used in the preparation of sample particles.

[0026] Figure 3 This is a graph showing the LSV evaluation results for compounds SE-4 and SE-10. Detailed Implementation

[0027] The compounds, solid electrolytes, and energy storage devices of the present invention will be described in detail below.

[0028] Compounds The compounds of the present invention are halogen compounds that satisfy the following formula (1).

[0029] D α M β X 6-γ A γ …(1) (In formula (1), α and β Each is an independent value greater than 0. c Values ​​greater than 0 and less than 6, where D is an alkali metal element, M contains elements other than alkali metals that become metal cations, X is a halogen element, and A is a group containing two or more elements that become polyatomic anions. In formula (1) above, D is an alkali metal element. Examples of D include at least one of Li, Na, and K. From the perspective of exhibiting high ionic conductivity, D preferably contains at least one of Li and Na, more preferably Li or Na. When D is Li, the compound satisfying formula (1) above is suitable as a solid electrolyte material for energy storage devices where the ion carrier is lithium ions. When D is Na, the compound satisfying formula (1) above is suitable as a solid electrolyte material for energy storage devices where the ion carrier is sodium ions. In particular, because Na is abundant and inexpensive, it is useful as a solid electrolyte material for realizing the practical application of energy storage devices.

[0030] M includes elements other than alkali metals that become metal cations. Examples of elements other than alkali metals that become metal cations include those from Groups 2 to 17. Specifically, examples include Ta, Y, Ce, Ti, Ni, Zr, Ga, Ge, Hf, Ca, Te, Sr, Mg, Al, V, Cr, Mn, Fe, Co, Cu, Zn, Nb, Mo, Tc, Ru, Rh, Pd, Cd, Sn, Sb, Ba, La, In, W, Pb, Sm, Eu, Tb, Dy, Tl, Bi, Sc, and Ag. It should be noted that M may contain only one element other than alkali metal that becomes a metal cation, or it may contain two or more.

[0031] From the perspective of obtaining compounds with higher ionic conductivity, elements other than alkali metals contained in M ​​that become metal cations, with the ionic radius of that element set as r... M When [Å], it is preferable to satisfy 0.3≤r M ≤1.0, more preferably 0.4≤r M ≤0.9. Regarding the elements in M ​​that become metal cations other than alkali metals, their valence is not particularly limited, but preferably valence 5 or lower. Furthermore, M preferably contains elements with a valence of 4 or lower, and more preferably elements with a valence of 3 or lower. It is speculated that by further reducing the valence of the elements that become metal cations other than alkali metals, the amount of alkali metal ions moving within the compound increases through charge compensation, thereby achieving a balance between good antioxidant properties and high ion conductivity.

[0032] It should be noted that when M contains elements with a valence of 4 or less that act as metal cations other than alkali metals, these metal cations can further include elements with a valence of 5 or more in addition to elements with a valence of 4 or less. Similarly, when M contains elements with a valence of 3 or less that act as metal cations other than alkali metals, these metal cations can further include elements with a valence of 4 or more in addition to elements with a valence of 3 or less.

[0033] In particular, elements other than alkali metals included in M ​​that become metal cations satisfy 0.3 ≤ r M In the case of elements with a valence of ≤1.0 and containing elements with a valence of 5 or less, it is preferable from the viewpoint of being able to further improve the ionic conductivity of the compound satisfying the above formula (1), and even more preferably, satisfying 0.4≤r M ≤0.9. Specifically, M preferably contains at least one element selected from Ta, Y(3+), Ce(4+), Ti(2+), Ni(4+), Zr, Ga, Ge, Hf, Ca, Te, In, Bi, Sn and Sc, more preferably contains at least one element selected from Ta, Y(3+), Ce(4+), Ti(2+), Ni(4+), In, Zr, Ga, Ge, Hf, Sn and Sc, and particularly preferably contains at least one element selected from Ta, Zr, Hf, Ge, Ga, Sn and Sc.

[0034] M may include elements that are metal cations (other than alkali metals) as well as elements that are non-metal cations. Examples of elements that are non-metal cations include at least one selected from Si, P, and B. From the viewpoint of obtaining compounds with superior ionic conductivity, M is preferably an element that is a metal cation (other than alkali metals).

[0035] X is a halogen element. X can be selected from at least one of F (fluorine), Cl (chlorine), Br (bromine), and I (iodine). From the viewpoint of obtaining a compound that possesses both good antioxidant properties and high ionic conductivity, X preferably contains Cl, and more preferably Cl.

[0036] A is a group of atoms containing two or more elements, known as a polyatomic anion (hereinafter simply referred to as a "polyatomic anion"). There are no particular restrictions on the types of elements constituting a polyatomic anion; they can be typical elements, transition elements, or combinations thereof. As a specific example of a polyatomic anion providing the group A, OH can be cited. - NO3 - CH3COO - (SO4) 2- (CO3) 2-(PO4) 3- (BO3) 3- (MnO) 4- (ZnCl4) 2- (AlCl4) - (BCl4) - (CoF6) 2- (BeF4) 2- (NiF6) 2- (SiO4) 4- It should be noted that A may contain only one type of atomic group that can be a polyatomic anion, or it may contain two or more types.

[0037] In the above, A preferably contains an oxygen atom. Furthermore, from the viewpoint of ionic conductivity, A preferably contains an inorganic polyatomic anion. Halogen compounds in which a portion of the halogen element is replaced by a polyatomic anion exhibit high ionic conductivity and have the advantage of being easily synthesized.

[0038] It should be noted that the possibility of using, for example, metal oxide crystals or metal peroxides as raw materials for halogen-based solid electrolytes has also been considered. However, metal oxide crystals are generally hard and have poor plasticity. Therefore, there is a concern that the reduced plasticity of the solid electrolyte due to the presence of metal oxide crystal residues may hinder the formation of a good interface with the electrode active material and the current collector. In addition, metal peroxides generally react easily with flammable or easily oxidized substances when mixed with them, due to heating, impact, or friction, resulting in poor processability. In contrast, by replacing part of the halogen element with a polyatomic anion, it is possible to obtain a solid electrolyte with good processability and high ionic conductivity while fully maintaining the plasticity characteristic of halogen-based solid electrolytes.

[0039] From the perspective of obtaining compounds with higher ionic conductivity, let the ionic radius of A in the above equation (1) be r. A When [Å], it is preferable to satisfy 0.8≤r A ≤2.9, more preferably 0.9≤r A ≤2.7, further optimization satisfies 1.0≤r A ≤2.6, and further preferred to satisfy 1.1≤r A≤2.5. Furthermore, the valence of the polyatomic anions constituting A is not particularly limited, but it is preferable to include polyatomic anions with a valence of 2 or higher, and more preferably polyatomic anions with a valence of 3 or higher. It is speculated that by further increasing the valence of the polyatomic anions, the amount of alkali metal ions moving within the compound increases through charge compensation, thereby exhibiting good antioxidant properties and achieving high ionic conductivity.

[0040] It should be noted that when A contains a group of atoms that are polyatomic anions with a valence of 2 or higher, A may, in addition to containing a group of atoms that are polyatomic anions with a valence of 2 or higher, further contain a group of atoms that are polyatomic anions with a valence of 1. Similarly, when A contains a group of atoms that are polyatomic anions with a valence of 3 or higher, A may, in addition to containing a group of atoms that are polyatomic anions with a valence of 3 or higher, further contain a group of atoms that are polyatomic anions with a valence of 1 or 2.

[0041] From the perspective of further improving the ionic conductivity of compounds that satisfy the above formula (1), A is preferably a polyatomic anion group with a valence of 2 or higher, and satisfies 0.8 ≤ r A ≤2.9. Furthermore, more preferably, A is a polyatomic anion with a valence of 2 or higher, and satisfies 0.9≤r A ≤2.7, further optimization satisfies 1.0≤r A ≤2.6, and further preferred to satisfy 1.1≤r A ≤2.5. Specifically, A is preferably selected from (SO4). 2- (CO3) 2- (PO4) 3- (BO3) 3- (MnO) 4- And (SiO4) 4- At least one of the following, more preferably selected from (CO3). 2- (BO3) 3- (PO4) 3- (SO4) 2- And (SiO4) 4- At least one of the following, more preferably selected from (CO3). 2- (BO3) 3- And (PO4) 3- At least one of them. In addition, if A contains a group of atoms that are polyatomic anions with a valence of 3 or higher, it is particularly preferred in terms of improving the ionic conductivity of the compound that satisfies the above formula (1) and ensuring good antioxidant properties.

[0042] In the above formula (1)α and β These are values ​​greater than 0. α and β than ( α / β )express α and β In the case of 1.0 < α / β ≤3.0, more preferably 1.1≤ α / β ≤2.5, further optimization satisfies 1.2≤ α / β ≤2.4, and further preferred to satisfy 1.4≤ α / β ≤2.1. By making α / β By satisfying the above range, the ratio of alkali metal elements that can serve as ion carriers can be optimized, resulting in compounds with significantly improved ion conductivity.

[0043] c Values ​​greater than 0 and less than 6. From the perspective of obtaining compounds with excellent ionic conductivity, c Preferably, it is 0.05 or higher; more preferably, 0.10 or higher; even more preferably, 0.15 or higher; and still even more preferably, 0.20 or higher. Additionally, c Preferably 5 or less, more preferably 3 or less, further preferably 1 or less, and even more preferably 0.50 or less. Regarding c In use c and β than ( c / β In the case of (), it is preferable to satisfy 0.10≤ c / β ≤0.50, more preferably 0.15≤ c / β ≤0.45, further optimized to satisfy 0.20≤ c / β ≤0.40.

[0044] The halogen compounds of the present invention need to satisfy the above formula (1). Among them, the halogen compounds of the present invention are particularly preferably satisfied with the following formula (2).

[0045] Na 1+y1+2×(y2)+3×(y3)+z1+2×(z2)+3×(z3) Ta 1-y1-y2-y3 M1 y1 M2 y2 M3 y3 Cl 6-z1-z2-z3 A1 z1 A2 z2 A3 z3 …(2) (In formula (2), y1, y2, y3, z1, z2 and z3 are each independently a value greater than or equal to 0, M1 is an element that becomes a tetravalent metal cation, M2 is an element that becomes a trivalent metal cation, M3 is an element that becomes a divalent metal cation, A1 is a group of atoms containing two or more elements that becomes a divalent polyatomic anion, A2 is a group of atoms containing two or more elements that becomes a trivalent polyatomic anion, and A3 is a group of atoms containing two or more elements that becomes a tetravalent polyatomic anion, satisfying 0 < y1 + y2 + y3 < 1 and 0 < z1 + z2 + z3 < 6.) In the above formula (2), M1, M2, and M3 can be represented as elements that are tetravalent metal cations, trivalent metal cations, and divalent metal cations, respectively, in specific examples of M. Similarly, A1, A2, and A3 can be represented as atomic groups that are divalent polyatomic anions, trivalent polyatomic anions, and tetravalent polyatomic anions, respectively, in specific examples of A.

[0046] Regarding y1, y2, and y3, in order to obtain compounds exhibiting higher Na ion conductivity, it is preferable that y1 > 0.10, more preferably that y1 > 0.12, and even more preferably that y1 > 0.15. Furthermore, it is preferable that y1 < 0.40, more preferably that y1 < 0.35, and even more preferably that y1 < 0.30.

[0047] y2 and y3 can be y2+y3=0, preferably y2+y3>0, more preferably y2+y3>0.05, and even more preferably y2+y3>0.10. In addition, it is preferable that y2+y3<0.30, more preferably y2+y3<0.25, and even more preferably y2+y3<0.20.

[0048] Furthermore, it is preferable to satisfy y1+y2+y3>0.10, more preferably to satisfy y1+y2+y3>0.15, and even more preferably to satisfy y1+y2+y3>0.20. In addition, it is preferable to satisfy y1+y2+y3<0.70, more preferably to satisfy y1+y2+y3<0.65, and even more preferably to satisfy y1+y2+y3<0.60.

[0049] Regarding z1, z2, and z3, in order to obtain compounds exhibiting higher Na ion conductivity, it is preferable that z1 > 0.10, more preferably that z1 > 0.12, and even more preferably that z1 > 0.15. Furthermore, it is preferable that z1 < 0.40, more preferably that z1 < 0.35, and even more preferably that z1 < 0.30.

[0050] z2 and z3 can be z2+z3=0, preferably z2+z3>0, more preferably z2+z3>0.05, and even more preferably z2+z3>0.10. In addition, it is preferable that z2+z3<0.30, more preferably z2+z3<0.25, and even more preferably z2+z3<0.20.

[0051] Furthermore, it is preferable to satisfy z1+z2+z3>0.10, more preferably z1+z2+z3>0.15, and even more preferably z1+z2+z3>0.20. In addition, it is preferable to satisfy z1+z2+z3<5, more preferably z1+z2+z3<3, even more preferably z1+z2+z3<1, and even more preferably z1+z2+z3≤0.5.

[0052] It should be noted that in the above general formula representing the halogen compounds of the present invention, the sum of the stoichiometric ratios of X (halogen element) and A (atomic group that becomes a polyatomic anion) is set to 6. However, as long as the overall charge of the halogen compound is kept neutral, the sum of the stoichiometric ratios of X and A in the halogen compound does not have to be strictly 6. That is, as long as the overall charge of the halogen compound is kept neutral, the sum of the stoichiometric ratios of X and A in the halogen compound can be less than 6 or greater than 6. For example, regarding satisfying D... α M β X 6-(γ±δ) A γ±δ The compound (here, satisfying 0≤ d ≤1, D, M, X, A, α , β as well as c With respect to D, M, X, A, and in the above formula (1), α , β as well as c (For the same meaning), as long as the overall charge of the compound remains neutral, it is also included in the halogen compounds of the present invention.

[0053] The halogen compounds of the present invention are solid at room temperature (25°C). The halogen compounds of the present invention can be crystalline or amorphous. From the viewpoint of exhibiting higher ionic conductivity, the halogen compounds of the present invention preferably have an amorphous phase. Specifically, the mass fraction of the amorphous phase (hereinafter also referred to as "amorphous mass fraction") of the halogen compounds of the present invention is preferably 3% or more, more preferably 10% or more, further preferably 30% or more, even more preferably 50% or more, even more preferably 70% or more, and even more preferably 85% or more. There is no particular upper limit to the amorphous mass fraction, for example, it is 99% or less, preferably 95% or less. It should be noted that in this specification, the amorphous mass fraction is a value obtained by X-ray diffraction (XRD) using a reference intensity ratio (RIR) as a reference. Details of the determination method are as described in the examples below.

[0054] It should be noted that the amorphous mass fraction of the halogen compound satisfying equation (1) above can be arbitrarily adjusted by modifying the grinding time and temperature of the raw materials during the manufacture of the halogen compound, or by adjusting the type and doping amount of A. For example, the amorphous mass fraction can be increased by making the grinding time of the raw materials close to a specified time. This is believed to be because although extending the grinding time of the raw materials can promote amorphization, if the grinding time is too long, the heat generated during grinding will lead to thermal relaxation, thereby promoting crystallization. In addition, for example, the amorphous mass fraction can be increased by increasing the type of A to achieve diversification.

[0055] The composition of halogen compounds satisfying equation (1) above can be determined using known analytical methods. Specifically, the compositions of D, M, and X can be determined by energy-dispersive X-ray spectroscopy or X-ray photoelectron spectroscopy. In addition, the composition of A can be determined by combining the above-mentioned spectroscopic methods with Raman spectroscopy or infrared spectroscopy.

[0056] <Method for manufacturing compounds that satisfy formula (1)> Compounds that satisfy the above formula (1) are typically those with D α M β In a halide with X6 as the basic framework, a compound is formed by replacing a portion of the halogen element (X) with a polyatomic anion group (A) containing two or more elements. The method for manufacturing the compound satisfying formula (1) above is not particularly limited. For example, the compound satisfying formula (1) above can be manufactured by a method including the weighing and pulverizing steps shown below.

[0057] Weighing process: A process of weighing multiple supplied components that contain one or more of the elements D, M, X and A in one component, in a manner that satisfies the stoichiometric ratio of the composition shown in formula (1) above. Grinding process: A process of grinding multiple feed ingredients that have been weighed in the weighing process. The following is a detailed explanation of each process.

[0058] (Weighing process) As raw materials for compounds that satisfy the above formula (1), the supply components corresponding to the elements used to obtain the target halogen compound can be used for D supply component (alkali metal element supply component), M supply component (supply component of elements other than alkali metal elements that become metal cations), X supply component (halogen element supply component) and A supply component (supply component of atomic groups that become polyatomic anions).

[0059] As the supply components D, M, X, and A for obtaining the compound satisfying formula (1) above, for example, carbonates, bicarbonates, sulfates, sulfites, nitrates, nitrites, phosphates, acetates, citrates, borates, silicates, oxides, hydroxides, halides (e.g., chlorides), sulfides, etc., containing these elements can be used. The supply component can be a compound containing two or more of the elements D, M, X, and A. From the viewpoint of being able to efficiently manufacture the compound satisfying formula (1) above, alkali metal salts and / or halides can preferably be used as supply components. In the case of obtaining a halogen-based compound having an amorphous phase as the compound satisfying formula (1) above, it does not matter whether the supply component is amorphous. That is, the supply component can have a crystalline phase or an amorphous phase. In addition, the supply component can be any of solid, liquid, and gas.

[0060] The weighing of the supplied components can be carried out in a conventional manner to satisfy the stoichiometric ratio of the composition shown in equation (1) above. When weighing the supplied components, it is preferable to carry out the weighing under an inert gas atmosphere (e.g., argon atmosphere, nitrogen atmosphere). It should be noted that if some of the halogen elements volatilize during the mixing process in the subsequent mixing step while mechanical energy is applied to the supplied components, it is preferable to weigh the supplied components taking into account the amount of volatilization.

[0061] (Grinding process) In the pulverization process, it is preferable to pulverize multiple feed components weighed in the weighing process while applying mechanical energy. Based on this method, it is deduced that amorphization occurs in the mixture through the mechanochemical reaction of multiple feed components, resulting in a compound exhibiting high ionic conductivity. There is no particular limitation on the method of pulverizing while applying mechanical energy (i.e., mechanochemically) to the feed components. For example, various equipment such as ball mills (planetary ball mills, etc.), bead mills, mixers, homogenizers, pulverizers, homogenizing mixers, and dispersant-type mixers can be used. In addition, in the case of manufacturing compounds satisfying the above formula (1) on a small scale, it is also possible to mix multiple feed components placed in a mortar with a pestle.

[0062] The pulverization of the supplied components can be carried out in a dry or wet manner. In particular, when manufacturing a compound that satisfies the above formula (1), the dry pulverization process eliminates the need for a solvent removal step and can produce a halogen compound exhibiting high ionic conductivity, which is therefore industrially advantageous.

[0063] The temperature of the feed component during pulverization is not particularly limited. In the pulverization process, the pulverization of the feed component can be carried out at room temperature or under cooling. Furthermore, multiple pulverization processes of the feed component can be performed. When multiple pulverization processes of the feed component are performed, the processing conditions (pulverization method, temperature, time, etc.) in each pulverization process can be the same or different. For example, a pretreatment can be performed by gently mixing and pulverizing multiple feed components at room temperature, followed by the present treatment where the mixture obtained from the pretreatment is pulverized at room temperature or under cooling, thereby obtaining the halogen compound of the present invention.

[0064] From the perspective of obtaining halogen compounds exhibiting higher ionic conductivity, it is preferable to pulverize multiple feed components weighed in the weighing process under cooling during the pulverization step. According to this method, cooling at low temperatures (e.g., below 0°C) can be continuously achieved during the pulverization of the feed components. This suppresses thermal relaxation during pulverization, inhibiting crystallization of the product (specifically, the synthesized product based on mechanochemical reactions), thus presumably leading to the acquisition of halogen compounds with a higher amorphous mass fraction. Furthermore, it is presumed that the compound's brittleness increases at low temperatures, thereby resulting in compounds with smaller particle sizes compared to pulverization at room temperature.

[0065] The method for cooling the multiple supply components is not particularly limited, but from the perspective of simplifying the pulverization process, the use of a cooling medium is preferred. The cooling medium can be any of solid, liquid, and gas, or a combination of two or more of them. Examples of cooling media include ice, dry ice, chilled water, liquid nitrogen, liquid argon, and liquid helium. The cooling temperature is preferably below -20°C, more preferably below -40°C, further preferably below -60°C, even more preferably below -80°C, and particularly preferably below -90°C. By pulverizing the supply components at such low temperatures, halogen compounds exhibiting higher ion conductivity can be obtained. Furthermore, from the perspective of easily achieving cooling at temperatures below -80°C, preferably below -90°C, liquid nitrogen is particularly preferred as the cooling medium.

[0066] Figure 1 This describes an example of a grinding processing apparatus 10 equipped with a cooling mechanism based on a cooling medium. Figure 1 The grinding and processing device 10 constitutes a planetary ball mill device.

[0067] exist Figure 1 The grinding processing apparatus 10 includes: a main body 11 with a bottom and an opening at the top; and a cover 12 that covers and seals the opening of the main body 11. The main body 11 is an insulated container that is large enough to house the grinding jar 13 inside. When the grinding jar 13 is housed inside, a gap 14 is formed between the grinding jar 13 and the inner wall of the main body 11.

[0068] The grinding jar 13 is a sealed container comprising a main body 13a and a lid 13b, which houses the sample M to be ground and the grinding balls 15 during grinding. The main body 13a is made of, for example, metal or ceramic. The grinding balls 15 are appropriately made of known grinding balls formed from materials such as metal, ceramic, or natural minerals. The grinding processing apparatus 10 includes a support 16 that supports the grinding jar 13 when it is housed inside the main body 11, and a rotation mechanism 17 that causes the grinding jar 13 supported by the support 16 to rotate and revolve. The support 16 supports the grinding jar 13 by clamping its side portion from above.

[0069] The grinding processing apparatus 10 is equipped with a cooling mechanism 18 that uses a cooling medium L to cool the grinding jar 13 housed in the main body 11. Specifically, the grinding processing apparatus 10 has a supply port 18a formed at the opening of the main body 11, through which the cooling medium L can be supplied from the outside to the gap 14. In addition, a flow port 18b is formed on the upper part of the support 16, which communicates the gap 14 with the space above the grinding jar 13 disposed in the main body 11, through which the cooling medium L can be supplied to the upper part of the grinding jar 13. Liquid nitrogen is preferably used as the cooling medium L.

[0070] When grinding the sample M using the grinding processing device 10, firstly, the sample M and the grinding balls 15 are placed inside the main body 13a of the jar. After sealing with the cover 13b, the grinding jar 13 is held in place by the support 16 and positioned inside the main body 11. Then, the cooling medium L is introduced through the supply port 18a, filling the area around (sides and top) of the grinding jar 13 with the cooling medium L. After sealing with the cover 12, the rotating mechanism 17 is operated. Thus, while the grinding jar 13 remains in contact with the cooling medium L, it rotates and revolves, grinding the sample M under the cooling of the cooling medium L.

[0071] When multiple supplied components are pulverized under cooling medium L, the grinding time is, for example, 10 minutes to 180 minutes, preferably 20 minutes to 150 minutes. The rotational and revolution speed of the grinding jar 13 is, for example, 50 rpm to 500 rpm, preferably 100 rpm to 450 rpm.

[0072] Furthermore, when the pulverization process of the supplied components is carried out at room temperature, in order to suppress the promotion of crystallization of the product due to the heat generated during pulverization, it is preferable to alternately perform pulverization and cooling processes. In this case, the cooling process can be natural cooling by placing the product at room temperature, or cooling using a cooling unit (e.g., cooling using a refrigerator, dry ice, air supply device, etc.). From the viewpoint of suppressing the promotion of crystallization of the product and obtaining halogen compounds with better ion conductivity, in the pulverization process at room temperature, it is preferable to set the total pulverization time to 100 hours or less, more preferably 75 hours or less, and even more preferably 60 hours or less.

[0073] As described above, a compound satisfying formula (1) can be obtained. Since the compound satisfying formula (1) has high conductivity of alkali metal ions, it can be used as a solid electrolyte material for energy storage devices, thus enabling the production of energy storage devices with high ion conductivity.

[0074] Solid Electrolytes The solid electrolyte of the present invention (hereinafter also referred to as "this electrolyte") comprises a compound satisfying the above formula (1). Furthermore, this electrolyte may further comprise components different from the compound satisfying the above formula (1) (hereinafter also referred to as "other components"). Other components are not particularly limited. Examples of other components include organic solid electrolytes, inorganic solid electrolytes other than the compound satisfying the above formula (1) (e.g., ceramic electrolytes, glass electrolytes, etc.), binders, conductive additives (carbon, etc.). The content of other components in this electrolyte can be appropriately set within a range that does not impair the effects of the present invention.

[0075] When using a compound satisfying equation (1) as a solid electrolyte material, the average particle size of the compound satisfying equation (1) is, for example, 0.01, determined by analyzing particle images observed using a scanning electron microscope. m m or more and 20 m Below m. From the viewpoint of material processability, the number-average particle size of the compound satisfying the above formula (1) is preferably 0.05. m m or more, preferably 0.1 m The particle size of the compound satisfying formula (1) is considered to be greater than m. It is believed that when a compound satisfying formula (1) is used as a solid electrolyte in combination with a positive or negative electrode active material, the smaller the particle size of the compound satisfying formula (1), the easier it is to enter the gaps between the active materials, thereby reducing voids in the positive or negative electrode layer and improving the performance of the energy storage device. From this perspective, the number-average particle size of the compound satisfying formula (1) is preferably 10 μm. m m or less, preferably 5 m For m and below, further optimization is preferred. m For m and below, 0.5 is further preferred. m Below m.

[0076] To achieve high ionic conductivity, inorganic solid electrolytes are typically produced by pressing powder into shape and then sintering it at high temperatures. This improves the bonding between particles and between the electrode and the electrolyte, thereby reducing interfacial resistance. However, sintering is an energy-intensive process, necessitating the introduction of large-area sintering equipment for industrial applications. In this regard, compounds satisfying equation (1) are useful for exhibiting high ionic conductivity even without sintering.

[0077] For compounds satisfying formula (1) above, the ionic conductivity measured by AC impedance spectroscopy at 25°C is preferably 0.30 mS / cm or higher. From the viewpoint of obtaining a high-performance energy storage device, the ionic conductivity under the same conditions is more preferably 0.35 mS / cm or higher, even more preferably 0.40 mS / cm or higher, even more preferably 0.60 mS / cm or higher, and still even more preferably 1.0 mS / cm or higher. It should be noted that the details of the method for measuring ionic conductivity are as described in the examples described later.

[0078] Energy Storage Equipment The energy storage device of the present invention (hereinafter also referred to as "the device") comprises a solid electrolyte containing a compound satisfying the above formula (1). Examples of the device include secondary batteries and capacitors. In the case of the device being a secondary battery, one possible configuration is an all-solid-state battery. In this case, considering the excellent conductivity of Na ions, compounds where D in the above formula (1) is Na are preferably used in sodium-ion secondary batteries. Furthermore, considering the excellent conductivity of Li ions, compounds where D in the above formula (1) is Li are preferably used in lithium-ion secondary batteries.

[0079] In secondary batteries, if stored while charged, the higher the electronic conductivity of the solid electrolyte, the faster the self-discharge rate and the greater the energy loss. From this perspective, when using a compound satisfying formula (1) as the solid electrolyte, a compound with low electronic conductivity is preferred. Specifically, the electronic conductivity of the compound satisfying formula (1) is preferably 1.0 × 10⁻⁶. -9 S / cm or less, preferably 7.0×10 -10 Below S / cm, 4.0×10 is further preferred. -10 Below S / cm, 2.0×10 is even more preferred. -10 Below S / cm, 1.0×10 is even more preferred. -10 Below S / cm, a further preferred value is 9.0×10. -11 Below S / cm.

[0080] An all-solid-state sodium-ion secondary battery, which is one embodiment of this device, will be described. The sodium-ion secondary battery is a laminate comprising an electrode layer and a solid electrolyte layer. The electrode layer includes a positive electrode layer and a negative electrode layer, and a solid electrolyte layer is disposed between the positive and negative electrode layers, such that the solid electrolyte layer is in contact with the electrode layer.

[0081] The materials constituting the positive and negative electrode layers are not particularly limited, and can be appropriately selected from materials known as electrode materials for sodium-ion secondary batteries. For example, the positive electrode layer can be composed of a positive current collector and a positive electrode flux layer. As the positive current collector, metal foils such as aluminum, titanium, and stainless steel can be used. The positive electrode flux layer is a layer containing the positive electrode active material and is disposed on the surface of the positive current collector. The positive electrode active material only needs to be able to absorb and release sodium, and there are no particular restrictions. Examples of positive electrode active materials include Na2FeP2O7, NaFePO4, Na3V2(PO4)3, and NaNi. 0.5 Mn0 .5 O2 and other transition metal oxides. In addition, the positive electrode mixture layer may contain solid electrolyte powder, conductive additives (e.g., carbon), binders, etc., as needed. It is preferable to use a compound that satisfies the above formula (1) as the solid electrolyte powder.

[0082] In particular, when the compound satisfying formula (1) is light-colored (preferably white), and a mixture layer is made by combining a dark-colored active substance with the compound, the operator can easily visually confirm that the active substance or the mixture of active substances is combined with the compound satisfying formula (1). Such a compound satisfying formula (1) is convenient and easy to use as a solid electrolyte material in the manufacture of energy storage devices.

[0083] The negative electrode layer can be composed of a negative electrode current collector and a negative electrode binder layer. Copper, aluminum, stainless steel, or other metal foils can be used as the negative electrode current collector. The negative electrode binder layer is a layer containing the negative electrode active material and is disposed on the surface of the negative electrode current collector. Examples of negative electrode active materials include hard carbon and Na-Ti-O compounds. Furthermore, the negative electrode binder layer may contain, as needed, solid electrolyte powder, conductive additives, binders, etc. A compound satisfying the above formula (1) can be used as the solid electrolyte powder.

[0084] The solid electrolyte layer is preferably formed of a solid electrolyte containing a compound satisfying formula (1) above. It should be noted that, in cases where the positive electrode mixture layer and / or the negative electrode mixture layer contain a compound satisfying formula (1) above, the solid electrolyte layer of this device is not limited to containing a compound satisfying formula (1) above. The thickness of the solid electrolyte layer is not particularly limited and can be appropriately set according to the application of the secondary battery, etc. For example, the thickness of the solid electrolyte layer is 5 mm. m m~5000 m From the perspective of miniaturizing, lightening, and increasing the capacity of all-solid-state secondary batteries by making the solid electrolyte layer as thin as possible, the thickness of the solid electrolyte layer is preferably 50 μm. m m or less, preferably 20 m For m and below, 10 is further preferred. m Below m.

[0085] There are no particular limitations on the method for manufacturing the solid electrolyte layer and the sodium-ion secondary battery; known methods can be appropriately adopted depending on the battery structure, etc. For example, a molded body of the electrolyte, which serves as the solid electrolyte layer, can be sandwiched between a positive electrode layer and a negative electrode layer, and preferably subjected to a pressure treatment for bonding, thereby manufacturing a laminate having a positive electrode layer, a solid electrolyte layer, and a negative electrode layer. Alternatively, the electrolyte before molding can be sandwiched between a positive electrode layer and a negative electrode layer and housed in a container, and the housed body can preferably be subjected to a pressure treatment for bonding, thereby manufacturing a laminate having a positive electrode layer, a solid electrolyte layer, and a negative electrode layer. The laminate having a positive electrode layer, a solid electrolyte layer, and a negative electrode layer is usually housed in a casing for use as a secondary battery.

[0086] This device is not limited to the above-described configuration where the charge carriers for ion conduction are sodium ions. For example, it could also be a secondary battery using other alkali metal ions such as lithium ions or potassium ions as charge carriers. Alternatively, this device could also be a capacitor. One example of a capacitor is a configuration comprising an anode, a cathode, and a solid electrolyte, with a solid electrolyte layer disposed between the anode and cathode in connection with the electrodes.

[0087] Energy storage devices containing this electrolyte can be used for a variety of applications. Specifically, they can be used as power sources for various mobile devices such as mobile phones, personal computers, smartphones, game consoles, and wearable devices; various mobile vehicles such as electric vehicles, hybrid vehicles, robots, and drones; and various electrical and electronic devices such as digital cameras, camcorders, music players, power tools, and home appliances.

[0088] Example The following is a detailed description based on embodiments. It should be noted that the present invention is not limited to these embodiments. Unless otherwise specified, "parts" and "%" refer to "parts by mass" and "% by mass," respectively.

[0089] 1. Preparation of compounds In each embodiment and comparative example, the compound was manufactured by either method A or method B.

[0090] (1-1) Method A The raw materials were weighed separately in a glove box under an argon atmosphere and mixed using an agate mortar. The resulting mixture was then placed into a container containing 30g of... f The zirconia balls (5 mm in diameter) were sealed in a 45 mL zirconia container. The container containing the mixture was then sealed inside an overpot and milled using a planetary ball mill (FRITSCH, Pulverisette 7 Classic Line) at room temperature (25°C). Milling was performed at a rotational speed of 300 rpm for 15 minutes, followed by a 10-minute resting period, as one cycle. The number of cycles and operations shown in Table 1 for Examples 1, 3-5, 7-9, and Comparative Example 1 were repeated. It should be noted that the 10-minute resting period was for cooling the mixture. Then, the overpot and zirconia container were opened in a glove box under an argon atmosphere, and the zirconia balls were separated from the powder, thus obtaining a powdered compound.

[0091] (1-2) Method B The raw materials were weighed separately in a glove box under an argon atmosphere and mixed using an agate mortar. Then, using... Figure 1 The grinding apparatus 10 shown grinds the obtained mixture. First, the mixture is fed into a container containing 30g of... f The 5mm zirconia balls were placed in a 45mL zirconia container (grinding jar 13) and sealed. The zirconia container containing the mixture was placed in an insulated container (main body 11) and secured. The insulated container was then filled with liquid nitrogen, and planetary ball milling was performed for 88 minutes at a rotation / revolution speed of 320 rpm. During this process, rotation was stopped every 24 minutes, liquid nitrogen was added to the insulated container, and the rotation was restarted. It should be noted that the temperature of the zirconia container during grinding was maintained within the range of -100℃ to -196℃. Then, the zirconia container was opened in a glove box under an argon atmosphere, and the zirconia balls were separated from the powder, thereby obtaining a powdered compound.

[0092] (2-1) Example 1 To ensure that the molar ratio of each element in the final product is as shown in Example 1 of Table 1 (Na:Ta:Zr:Cl:CO3 = 1.5:0.75:0.25:5.75:0.25), 0.178 g of sodium chloride (manufactured by Fujifilm and Koko Pure Chemicals Co., Ltd., purity 99.5%), 0.652 g of tantalum chloride (V) (manufactured by Acros Organics Co., Ltd., purity 99.99%), 0.142 g of zirconium chloride (IV) (manufactured by Strem Chemicals Co., Ltd., purity 99.5%), and 0.032 g of sodium carbonate (manufactured by Fujifilm and Koko Pure Chemicals Co., Ltd., purity 99.8%) were used as feed components. Each feed component was weighed in a glove box under an argon atmosphere, and the compound SE-1, a white powder, was obtained by the preparation method shown in Example 1 of Table 1 (Preparation Method A).

[0093] (2-2) Examples 2 to 9 and Comparative Example 1 Similar to Example 1, to ensure that the molar ratios of the elements in the final product were as shown in Table 1, each supplied component was weighed in a glove box under an argon atmosphere, and compounds SE-2 to SE-10, which are white powders, were obtained by the methods (method A or method B) shown in Examples 2 to 9 and Comparative Example 1 in Table 1. It should be noted that gallium(III) chloride (manufactured by Thermo Scientific, 99.999% purity) was used as the supplied component for Ga, Na3BO3 as the supplied component for BO3, Na3PO4 (manufactured by Sigma-Aldrich, ≥97.0% purity) as the supplied component for PO4, and tin(IV) chloride (manufactured by Sigma-Aldrich, 99.995% purity) as the supplied component for Sn.

[0094] 2. Evaluation For the compounds SE-1 to SE-10 of Examples 1 to 9 and Comparative Example 1, the amorphous mass fraction and ionic conductivity were measured. In addition, the electronic conductivity of the compound SE-4 of Example 4 was measured. Furthermore, the oxidation resistance of the compound SE-4 of Example 4 and the compound SE-10 of Comparative Example 1 was evaluated.

[0095] [Measurement and Results of Amorphous Mass Fraction and Ionic Conductivity] The details of the method for measuring the amorphous mass fraction and ionic conductivity are described below.

[0096] (1) Amorphous mass fraction Quantification of the amorphous mass fraction of compounds SE-1 to SE-10 was performed by the reference intensity ratio (RIR) method. In a glove box under an argon atmosphere, compounds SE-1 to SE-10 and α alumina (manufactured by FUJIFILM Wako Pure Chemical Corporation) were weighed to a mass ratio of 1:1 and mixed with an agate mortar. The obtained mixture was subjected to XRD measurement under the conditions shown below. Using the integral intensity of the strongest line of each of the compound and α alumina obtained from XRD measurement and the RIR value of NaTaCl₆, the amorphous mass fraction in each of the compounds SE-1 to SE-10 of Examples 1 to 9 and Comparative Example 1 was calculated and shown in Table 1. It should be noted that, from the XRD measurement results, no diffraction peak of Ta₂O₅ was detected in any of the compounds SE-1 to SE-10 of Examples 1 to 9 and Comparative Example 1.

[0097] <X-ray Diffraction (XRD) Measurement> XRD measurement of the compound was performed under the following conditions. In addition, the compound was placed in an airtight sample stage and sealed in a glove box under an argon atmosphere, and the measurement was performed under an atmospheric atmosphere.

[0098] X-ray diffractometer: MiniFlex 600 (manufactured by Rigaku Corporation) Characteristic X-ray: CuK α Measurement voltage: 40kV Measurement current: 15mA Measurement method: Continuous scanning Measurement range: 10°≤2 i θ≤60° Step size: 0.01° Scanning speed: 10° / min (2) Ionic conductivity Molded bodies of each of the compounds SE-1 to SE-10 were produced, alternating current impedance was measured, and the ionic conductivity was calculated using the measurement results.

[0099] (2-1) Production of the molded body A stamping die 20 (see reference) is used, which includes a module 21, an upper punch 22, and a lower punch 23. Figure 2 The molded body was fabricated in a glove box under an argon atmosphere. A module 21 containing 0.060 g of the compound obtained in step 1 above was placed on a lower punch 23, and an upper punch 22 was placed on the module 21. Then, the compound was compressed for 1 minute under a pressure of 382 MPa using a hydraulic press to obtain… f A 10mm round molded body.

[0100] (2-2) Measurement of AC impedance The AC impedance of the molded body obtained in (2-1) above was measured, and a complex impedance plot was generated. The measurement was performed using a multichannel potentiostat / galvanostat (Biologic, VSP) at a frequency of 10 Hz to 1 MHz, a voltage of 10 mV, and a temperature of 25 °C. It should be noted that during the measurement, the stamping die 20 containing the molded body was fixed in a glove box under an argon atmosphere and subjected to a constraint of 50 MPa.

[0101] (2-3) Calculation of ionic conductivity Using the terminal value of the right end of the arc in the complex impedance diagram obtained in (2-2) above as the resistance R of each molded body, the ionic conductivity is calculated using the following formula. s (Na ion conductivity). For each embodiment and comparative example, the ion conductivity is... s The values ​​are shown in Table 1.

[0102] s = (t / A) × (1 / R) s Ion conductivity t: Thickness of the molded body A: Area of ​​the current collector layer R: Resistance of the molded body [Table 1]

[0103] As shown in Table 1, compounds SE-1 to SE-9 from Examples 1 to 9 exhibit excellent Na-ion conductivity. Specifically, compounds SE-4 and SE-6 (Examples 4 and 6), which are doped with Zr, Ga, CO3, and BO3 in NaTaCl6, demonstrate even higher Na-ion conductivity compared to Examples 1, 7-9 with Example 4, and Examples 2 with Example 6. Furthermore, comparisons between Examples 1 and 2, and Examples 3 and 4, indicate that a higher amorphous mass fraction results in higher Na-ion conductivity.

[0104] Furthermore, comparing Examples 3-5 using Preparation Method A, Example 4, with 192 cycles, exhibited the highest Na ion conductivity. Regarding this result, it is believed that Example 3, with 20 cycles, could not achieve sufficient synthesis due to insufficient grinding, and the presence of unreacted substances hindered ion conduction, resulting in a decreased ion conductivity. Additionally, it is believed that Example 5, with 382 cycles, promoted crystallization and impurity formation due to thermal relaxation caused by excessive grinding, and the resulting crystals and impurities hindered ion conduction, resulting in a decreased ion conductivity. Furthermore, there is a correlation between the number of cycles and the amorphous mass fraction; a sufficiently high number of cycles results in a high amorphous mass fraction, and consequently, a tendency for increased Na ion conductivity. Conversely, both excessive and insufficient cycle numbers decrease the amorphous mass fraction, leading to a decreasing trend in Na ion conductivity.

[0105] In contrast, the Na ion conductivity of the undoped compound SE-10 (Comparative Example 1) was lower than that of the compounds SE-1 to SE-9 in Examples 1 to 9, resulting in poor practicality.

[0106] [Determination and Results of Electron Conductivity] (1) Construction of the measuring cell A stamping die 20 (see reference) is used, in which the upper punch 22 and lower punch 23 have been pre-plated with gold. Figure 2 The measuring cell was prepared in a glove box under an argon atmosphere. A module 21 containing 0.060 g of compound (SE-4) from Example 4 was placed on a lower punch 23, and an upper punch 22 was placed on the module 21. The measuring cell was then compressed for 1 minute using a hydraulic press at 382 MPa to obtain the measuring cell.

[0107] (2) Calculation of electronic conductivity Electronic conductivity was evaluated by DC polarization measurement. Measurements were performed using a multichannel potentiostat / galvanostat (Biologic, VSP) at voltages of 0.1V, 0.2V, 0.3V, 0.4V, and 0.5V, and a temperature of 25°C. It should be noted that the measurement cell was fixed in a glove box under an argon atmosphere and constrained at 50 MPa.

[0108] Read the steady current obtained by measurement, calculate the resistance (Re) using Ohm's law, and calculate the electronic conductivity (i) using the following mathematical formula (i). s e).

[0109] The electronic conductivity of compound (SE-4) in Example 4 ( s The value of e) is 8.2 × 10 -11 The S / cm ratio confirms that the electron conductivity is sufficiently low.

[0110] s e=(t / A)×(1 / Re)…(i) s e: Electron conductivity t: thickness of the sample A: Area of ​​the current collector layer Re: Resistance [Evaluation and Results of Antioxidant Properties] The antioxidant properties of compound SE-4 from Example 4 and compound SE-10 from Comparative Example 1 were evaluated by linear sweep voltammetry (LSV).

[0111] (1) Fabrication of LSV measurement cell A stamping die 20 (see reference) is used, in which the upper punch 22 and lower punch 23 have been pre-plated with gold. Figure 2 The LSV determination cell was prepared in a glove box under an argon atmosphere. A module 21 containing 0.030 g of Na3PS4 glass-ceramic was placed on the lower punch 23, and an upper punch 22 was placed on the module 21. The sample was then compressed for 1 minute using a hydraulic press at a pressure of 63 MPa.

[0112] After compression, remove the upper punch 22 and insert Na. 10 0.100g of Sn4 alloy was placed in module 21, and the upper punch 22 was placed on module 21. Then, the sample was compressed for 1 minute using a hydraulic press at a pressure of 63MPa.

[0113] After compression, the stamping die is reversed, the lower punch 23 is removed, and 0.030 g of compound SE-10 (an intermediate layer used to inhibit the oxidation reaction of Na3PS4 derived from LSV determination) is placed into module 21. The lower punch 23 is then placed in module 21. The sample is then compressed for 1 minute using a hydraulic press at a pressure of 63 MPa.

[0114] After compression, the lower punch 23 was removed, and 0.010 g of powder, pre-mixed in an agate mortar with compound SE-4 (Example 4) and Ketjen Black (manufactured by Lion Special Chemicals Co., Ltd.) at a mass ratio of 85:15, was placed into module 21. The lower punch 23 was then placed in module 21. The sample was then compressed for 1 minute using a hydraulic press at a pressure of 382 MPa, thereby obtaining Na. 10 A laminate of Sn4 alloy / Na3PS4 glass ceramic / SE-10 / (a mixture of SE-4 and Ketjen black).

[0115] The obtained stamping die 20 containing the laminate was fixed with a clamp and constrained at 50 MPa, thereby producing an LSV determination cell for compound SE-4 (Example 4).

[0116] In addition, the LSV assay cell for compound SE-10 (Comparative Example 1) was prepared as follows: Compound SE-10 was used instead of compound SE-4, and a laminate (Na) was prepared using the same method as the laminate of compound SE-4. 10 Sn4 alloy / Na3PS4 glass ceramic / SE-10 / (a mixture of SE-10 and Ketjen black)), a stamping die 20 containing the obtained laminate is fixed with a fixture and constrained at 50 MPa.

[0117] (2) LSV determination Connect the LSV measurement cell prepared in (1) to a multichannel potentiostatic / galvanostatic instrument (manufactured by Biologic, VSP) so that Na 10 The Sn4 alloy layer serves as both the reference and counter electrode, while the mixture of compound SE-4 and Ketjenblack (or a mixture of compound SE-10 and Ketjenblack) forms the working electrode. LSV measurements are performed under an argon atmosphere at 25°C. The scan rate is set to 0.5 mV / s, starting from the open-circuit voltage and scanning the potential up to 6 V (vs. Na / Na). + The LSV evaluation results of compounds SE-4 and SE-10 are shown in the figure. Figure 3 .

[0118] Depend on Figure 3 The results showed that the compound SE-4 (Example 4) doped with Zr, Ga, CO3 and BO3 in NaTaCl6 had the same antioxidant properties as the undoped compound SE-10 (Comparative Example 1).

[0119] The results above show that compounds satisfying equation (1) exhibit high ionic conductivity. Furthermore, compounds satisfying equation (1) have very low electronic conductivity, thus possessing both good antioxidant properties and high ionic conductivity.

[0120] This invention is not limited to the embodiments described above, and includes various modifications and variations within the same scope without departing from the spirit of the invention. Therefore, it should be understood that various combinations, forms, and other combinations and forms including only one element, its superordinate concept, or its subordinate concept also fall within the scope and spirit of this invention, in accordance with the above teachings.

[0121] Explanation of reference numerals in the attached figures 10… Grinding Processing Device 13…Grinding jar 20… Stamping dies.

Claims

1. A compound, characterized in that, It satisfies the following equation (1). D α M β X 6-γ A γ (1) In equation (1), α and β Each is an independent value greater than 0. γ Values ​​greater than 0 and less than 6, where D is an alkali metal element, M contains elements other than alkali metal elements that become metal cations, X is a halogen element, and A is a group of atoms containing two or more elements that become polyatomic anions.

2. The compound according to claim 1, wherein, In the formula (1), D is Na.

3. The compound according to claim 1, wherein, The compound has an ionic radius of r for elements other than the alkali metal that become metal cations. M When [Å], 0.4≤r is satisfied. M ≤0.

9.

4. The compound according to claim 1, wherein, M in the formula (1) contains at least one element selected from Ta, Zr, Hf, Ge, Ga, Sn and Sc.

5. The compound according to claim 1, wherein, In the formula (1), A has an oxygen atom.

6. The compound according to claim 1, wherein, In the formula (1), A contains atomic groups that can become inorganic polyatomic anions.

7. The compound according to claim 1, wherein, The compound has an ionic radius of A in formula (1) set to r. A When [Å], 0.9 ≤ r A ≤2.

7.

8. The compound according to claim 1, wherein, In the formula (1), X is Cl, i.e., chlorine.

9. The compound according to claim 1, wherein, The compound satisfies the following formula (2). Na 1+y1+2×(y2)+3×(y3)+z1+2×(z2)+3×(z3) Ta 1-y1-y2-y3 M1 y1 M2 y2 M3 y3 Cl 6-z1-z2-z3 A1 z1 A2 z2 A3 z3 (2) In equation (2), y1, y2, y3, z1, z2 and z3 are each independently a value greater than or equal to 0. M1 is an element that becomes a tetravalent metal cation, M2 is an element that becomes a trivalent metal cation, M3 is an element that becomes a divalent metal cation, A1 is a group of atoms containing two or more elements that becomes a divalent polyatomic anion, A2 is a group of atoms containing two or more elements that becomes a trivalent polyatomic anion, and A3 is a group of atoms containing two or more elements that becomes a tetravalent polyatomic anion, satisfying 0 < y1 + y2 + y3 < 1 and 0 < z1 + z2 + z3 < 6.

10. The compound according to claim 1, wherein, The mass fraction of the amorphous phase in the compound is 10% or more.

11. A method for producing the compound according to any one of claims 1 to 10, characterized in that, Include: A process of weighing multiple supplied components containing one or more elements of D, M, X and A from formula (1) in a manner that satisfies the stoichiometric ratio of the composition shown in formula (1); and The process of pulverizing the weighed multiple feed components under cooling with a cooling medium.

12. A solid electrolyte, characterized in that, The compound comprising any one of claims 1 to 10.

13. An energy storage device, characterized in that, It possesses the solid electrolyte as described in claim 12.

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