Solid electrolyte materials and batteries using solid electrolyte materials

Abstract

The solid electrolyte material disclosed herein contains Li, M, Al, O and X, wherein M is selected from at least one of Ta and Nb, and X is selected from at least one of F, Cl and Br.

Description

Technical Field

[0001] This disclosure relates to solid electrolyte materials and batteries using the solid electrolyte material. Background Technology

[0002] Patent document 1 discloses an all-solid-state battery using sulfide solid electrolyte material.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2011-129312 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] The purpose of this disclosure is to provide a novel solid electrolyte material with high utility.

[0008] Methods for solving problems

[0009] The solid electrolyte material disclosed herein contains Li, M, Al, O and X, wherein M is selected from at least one of Ta and Nb, and X is selected from at least one of F, Cl and Br.

[0010] The effects of the invention

[0011] This disclosure provides a novel solid electrolyte material with high utility. Attached Figure Description

[0012] Figure 1 A cross-sectional view showing the battery 1000 of the second embodiment.

[0013] Figure 2 A cross-sectional view showing the electrode material 1100 of the second embodiment.

[0014] Figure 3 A schematic diagram of a pressure forming mold 300 used to evaluate the ionic conductivity of solid electrolyte materials.

[0015] Figure 4A This is a diagram showing the X-ray diffraction patterns of the solid electrolyte materials in Examples 1 to 7.

[0016] Figure 4B This is a diagram showing the X-ray diffraction patterns of the solid electrolyte materials of Examples 8 and 9.

[0017] Figure 5 This is a diagram showing the X-ray diffraction patterns of the solid electrolyte materials of Comparative Examples 1 and 2.

[0018] Figure 6This is a graph showing the initial discharge characteristics of the battery in Example 1. Detailed Implementation

[0019] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. The present disclosure is not limited to the following embodiments.

[0020] (First Embodiment)

[0021] The solid electrolyte material of the first embodiment contains Li, M, Al, O and X, where M is selected from at least one of Ta and Nb, and X is selected from at least one of F, Cl and Br.

[0022] The solid electrolyte material of the first embodiment can, for example, have practical lithium-ion conductivity, and for example, can have high lithium-ion conductivity. Here, high lithium-ion conductivity is, for example, 1 × 10⁻⁶. -3 mS / cm or higher. That is, the solid electrolyte material of the first embodiment may, for example, have a density of 1×10⁻⁶ mS / cm. -3 Ionic conductivity above mS / cm.

[0023] The solid electrolyte material of the first embodiment can be used to obtain a battery with excellent charge-discharge characteristics. An example of this battery is an all-solid-state battery. An all-solid-state battery can be a primary battery or a secondary battery.

[0024] The solid electrolyte material of the first embodiment can maintain a high lithium-ion conductivity within the envisioned battery operating temperature range. Therefore, the battery using the solid electrolyte material of the first embodiment can operate stably even in environments with temperature variations. The battery operating temperature range is, for example, -30°C to 80°C.

[0025] Preferably, the solid electrolyte material of the first embodiment is substantially sulfur-free. "Substantially sulfur-free" means that the solid electrolyte material contains no sulfur as a constituent element, except for sulfur that inevitably mixes in as an impurity. In this case, the sulfur mixed in as an impurity in the solid electrolyte material is, for example, 1 mol% or less. It is preferable that the solid electrolyte material of the first embodiment is sulfur-free. Sulfur-free solid electrolyte materials do not produce hydrogen sulfide even when exposed to the atmosphere, thus exhibiting excellent safety. The sulfide solid electrolyte material disclosed in Patent Document 1 can produce hydrogen sulfide when exposed to the atmosphere.

[0026] To improve the ionic conductivity of the solid electrolyte material, the solid electrolyte material of the first embodiment may substantially be composed of Li, M, Al, O, and X. Here, "the solid electrolyte material of the first embodiment is substantially composed of Li, M, Al, O, and X" means that the ratio (i.e., mole fraction) of the total mass of Li, M, Al, O, and X to the total mass of all elements constituting the solid electrolyte material of the first embodiment is 90% or more. As an example, this ratio may also be 95% or more. The solid electrolyte material of the first embodiment may also be composed solely of Li, M, Al, O, and X.

[0027] The solid electrolyte material of the first embodiment also exhibits diffraction peaks in the X-ray diffraction pattern within a diffraction angle range of 2θ (hereinafter referred to as the first range) of 11.08° to 15.63°. With such a solid electrolyte material, pathways for lithium-ion diffusion are easily formed. As a result, the solid electrolyte material of the first embodiment has high lithium-ion conductivity.

[0028] The diffraction peaks in X-ray diffraction patterns are also simply referred to as "peaks".

[0029] The X-ray diffraction pattern of the solid electrolyte material in the first embodiment can be obtained using Cu-Kα rays (wavelength... and The wavelengths (0.15405 nm and 0.15444 nm) were obtained by X-ray diffraction based on the θ-2θ method.

[0030] The angle of a peak refers to the angle of maximum intensity of the mountain-like portion where the SN ratio is 3 or higher and the half-width (HW) is 10° or less. The HW refers to the angle of maximum intensity when the maximum intensity of the peak is set to I. MAX When, strength becomes I MAX The width is represented by the difference between the two diffraction angles, which is half the value of the signal. The S / N ratio is the ratio of the signal S to the background noise N.

[0031] To improve the ionic conductivity of solid electrolyte materials, X can also be at least one selected from Cl and Br.

[0032] To improve the ionic conductivity of solid electrolytes, M can also be Ta.

[0033] To improve the ionic conductivity of solid electrolyte materials, the ratio of the mass of Al to the total mass of M and Al can be between 5% and 70%. This ratio can be calculated using the mathematical formula: {(mass of Al) / (mass of M + mass of Al)} × 100. Hereinafter, this ratio will also be referred to as the Al / (M+Al) molar ratio.

[0034] To improve the ionic conductivity of solid electrolyte materials, the Al / (M+Al) molar ratio can be above 10% and below 70%.

[0035] To improve the ionic conductivity of solid electrolyte materials, the Al / (M+Al) molar ratio can be above 10% and below 60%.

[0036] To further improve the ionic conductivity of solid electrolyte materials, the Al / (M+Al) molar ratio can also be above 10% and below 40%.

[0037] The shape of the solid electrolyte material in the first embodiment is not limited. Examples of this shape include needle-like, spherical, and ellipsoidal shapes. The solid electrolyte material in the first embodiment may also be particles. The solid electrolyte material in the first embodiment may also be formed in the form of granules or plates.

[0038] When the solid electrolyte material of the first embodiment is in the form of particles (e.g., spheres), it can have a median particle size of 0.1 μm or more and 100 μm or less, or a median particle size of 0.5 μm or more and 10 μm or less. Therefore, the solid electrolyte material of the first embodiment and other materials can be well dispersed. The median particle size means the particle size (d50) that corresponds to the 50% volumetric cumulative distribution in a volumetric particle size distribution. The volumetric particle size distribution can be measured using a laser diffraction apparatus or an image analysis apparatus.

[0039] <Manufacturing Methods of Solid Electrolyte Materials>

[0040] The solid electrolyte material of the first embodiment can be manufactured by the following method.

[0041] Prepare and mix the raw material powder in a manner that yields the desired composition. Examples of raw material powders include oxides, hydroxides, halides, or acid halides.

[0042] As an example, when the solid electrolyte material is composed of Li, Ta, Al, O, and Cl, and the Al / (M+Al) molar ratio of the raw materials is 10%, that is, when M is Ta, X is Cl, and the Al / (M+Al) molar ratio of the raw materials is 10%, the raw material powders are mixed in a Li₂O₂:TaCl₅:AlCl₃ molar ratio of 1:1.8:0.2. M and X can be determined by selecting the raw material powders. The Al / (M+Al) molar ratio can be determined by selecting the molar ratio of the raw material powders. Alternatively, the raw material powders can be mixed in a pre-adjusted molar ratio to offset possible compositional changes during the synthesis process.

[0043] Reactants can be obtained by subjecting a mixture of raw material powders to a mechanochemical reaction within a mixing apparatus such as a planetary ball mill. This method is often referred to as mechanochemical milling. The reactants can also be calcined in a vacuum or an inert atmosphere. Alternatively, reactants can be obtained by calcining the mixture in a vacuum or an inert gas atmosphere. These methods yield the solid electrolyte material of the first embodiment. An inert atmosphere is, for example, argon or nitrogen.

[0044] By selecting the raw material powder, the mixing ratio of the raw material powder, and the reaction conditions, the position of the peak of the solid electrolyte material of the first embodiment, i.e. the composition of the crystalline phase, can be adjusted to the target composition.

[0045] The composition of solid electrolyte materials can be determined, for example, by inductively coupled plasma atomic emission spectrometry (ICP-AES) or ion chromatography. For instance, the compositions of Li, M, and Al can be determined by ICP-AES, while the composition of X can be determined by ion chromatography.

[0046] (Second Implementation)

[0047] The second embodiment will be described below. Matters described in the first embodiment will be omitted as appropriate.

[0048] The battery of the second embodiment includes a positive electrode, an electrolyte layer, and a negative electrode. The electrolyte layer is disposed between the positive electrode and the negative electrode. At least one solid electrolyte material selected from the positive electrode, the electrolyte layer, and the negative electrode is used, which contains the solid electrolyte material of the first embodiment.

[0049] The battery of the second embodiment has excellent charge and discharge characteristics because it contains the solid electrolyte material of the first embodiment.

[0050] Figure 1 A cross-sectional view showing the battery 1000 of the second embodiment.

[0051] The battery 1000 has a positive electrode 201, an electrolyte layer 202, and a negative electrode 203. The electrolyte layer 202 is disposed between the positive electrode 201 and the negative electrode 203.

[0052] The positive electrode 201 contains positive electrode active material particles 204 and solid electrolyte particles 100.

[0053] Electrolyte layer 202 contains an electrolyte material. The electrolyte material may be, for example, a solid electrolyte material.

[0054] The negative electrode 203 contains negative electrode active material particles 205 and solid electrolyte particles 100.

[0055] The solid electrolyte particles 100 are particles containing the solid electrolyte material of the first embodiment. The solid electrolyte particles 100 may also be particles containing the solid electrolyte material of the first embodiment as a main component. The term "particles containing the solid electrolyte material of the first embodiment as a main component" means particles containing, at most, the solid electrolyte material of the first embodiment in a molar ratio. The solid electrolyte particles 100 may also be particles composed of the solid electrolyte material of the first embodiment.

[0056] The positive electrode 201 contains a material that can insert and extract metal ions such as lithium ions. This material is, for example, a positive electrode active material (e.g., positive electrode active material particle 204).

[0057] Examples of positive electrode active materials include lithium-containing transition metal oxides, transition metal fluorides, polyanionic materials, fluorinated polyanionic materials, transition metal sulfides, transition metal sulfides, or transition metal nitrides. Examples of lithium-containing transition metal oxides include Li(Ni, Co, Al)O2, Li(Ni, Co, Mn)O2, or LiCoO2. From the perspective of battery cost and safety, lithium phosphate can also be used as a positive electrode active material.

[0058] In this disclosure, “(A, B, C)” means “selected from at least one of A, B and C”.

[0059] The positive electrode 201 may contain not only the solid electrolyte material of the first embodiment, but also transition metal fluoride oxides as the positive electrode active material. Even when the solid electrolyte material of the first embodiment is fluorinated with transition metal fluorides, it is difficult to form a resistive layer. As a result, the battery has high charge and discharge efficiency.

[0060] Transition metal fluorides contain both oxygen and fluorine. As an example, transition metal fluorides can also be composed of the formula Li. p Me q O m F nThe compound is represented by Me. Here, Me is selected from at least one of Mn, Co, Ni, Fe, Al, Cu, V, Nb, Mo, Ti, Cr, Zr, Zn, Na, K, Ca, Mg, Pt, Au, Ag, Ru, W, B, Si, and P, and satisfies the following mathematical formulas: 0.5 ≤ p ≤ 1.5, 0.5 ≤ q ≤ 1.0, 1 ≤ m < 2, and 0 < n ≤ 1. An example of such a transition metal fluoride oxide is Li. 1.05 (Ni 0.35 Co 0.35 Mn 0.3 ) 0.95 O 1.9 F 0.1 .

[0061] The positive electrode active material particles 204 can also have a median particle size of 0.1 μm or larger and 100 μm or smaller. When the positive electrode active material particles 204 have a median particle size of 0.1 μm or larger, the positive electrode active material particles 204 and the solid electrolyte particles 100 can be well dispersed in the positive electrode 201. As a result, the charge and discharge characteristics of the battery are improved. When the positive electrode active material particles 204 have a median particle size of 100 μm or smaller, the lithium diffusion rate within the positive electrode active material particles 204 is increased. As a result, the battery can operate at high output power.

[0062] The positive electrode active material particles 204 can also have a larger median particle size than the solid electrolyte particles 100. Therefore, the positive electrode active material particles 204 and the solid electrolyte particles 100 can be well dispersed.

[0063] In order to improve the energy density and output power of the battery, in the positive electrode 201, the ratio of the volume of the positive electrode active material particles 204 to the total volume of the positive electrode active material particles 204 and the solid electrolyte particles 100 can also be 0.30 or higher and 0.95 or lower.

[0064] Figure 2 This is a cross-sectional view showing the electrode material 1100 according to the second embodiment. The electrode material 1100 may, for example, be contained in the positive electrode 201. To prevent the electrode active material particles 206 (i.e., the positive electrode active material) from reacting with the solid electrolyte particles 100, a coating layer 216 may be formed on the surface of the electrode active material particles 206. This suppresses the rise of the battery's reactive overvoltage. Examples of coating materials contained in the coating layer 216 include sulfide solid electrolytes, oxide solid electrolytes, or halide solid electrolytes.

[0065] When the solid electrolyte particles 100 are sulfide solid electrolytes, the coating material can also be the solid electrolyte material of the first embodiment. The solid electrolyte material of the first embodiment is less prone to oxidation than sulfide solid electrolytes, thus suppressing the rise of the battery's reaction overvoltage.

[0066] To improve the energy density and output power of the battery, the positive electrode 201 can also have a thickness of more than 10 μm and less than 500 μm.

[0067] Electrolyte layer 202 contains an electrolyte material. This electrolyte material may be, for example, a solid electrolyte material. Electrolyte layer 202 may also be a solid electrolyte layer.

[0068] The electrolyte layer 202 may also contain the solid electrolyte material of the first embodiment. The electrolyte layer 202 may also be composed solely of the solid electrolyte material of the first embodiment.

[0069] The solid electrolyte material contained in the electrolyte layer 202 may also be composed of a solid electrolyte material different from that of the first embodiment. Examples of solid electrolyte materials different from those of the first embodiment are Li2MgX'4, Li2FeX'4, Li(Al, Ga, In)X'4, Li3(Al, Ga, In)X'6, or LiI. Here, X' is at least one selected from F, Cl, Br, and I.

[0070] Hereinafter, the solid electrolyte material of the first embodiment will be referred to as the first solid electrolyte material. Solid electrolyte materials that are different from the solid electrolyte material of the first embodiment will be referred to as the second solid electrolyte material.

[0071] The electrolyte layer 202 may contain not only a first solid electrolyte material but also a second solid electrolyte material. The first and second solid electrolyte materials may also be uniformly dispersed. The layers formed by the first and second solid electrolyte materials may also be stacked along the stacking direction of the battery 1000.

[0072] The electrolyte layer 202 can also have a thickness of more than 1 μm and less than 100 μm. When the electrolyte layer 202 has a thickness of more than 1 μm, short circuits are less likely to occur between the positive electrode 201 and the negative electrode 203. When the electrolyte layer 202 has a thickness of less than 100 μm, the battery can operate with high output power.

[0073] Other electrolyte layers can also be further disposed between the electrolyte layer 202 and the negative electrode 203. That is, a second electrolyte layer can also be further disposed between the electrolyte layer 202 and the negative electrode 203. For example, when the electrolyte layer 202 contains a first solid electrolyte material, the second electrolyte layer can also be composed of another solid electrolyte material that is electrochemically more stable than the first solid electrolyte material. Specifically, the reduction potential of the solid electrolyte material constituting the second electrolyte layer can also be lower than the reduction potential of the first solid electrolyte material. Therefore, the first solid electrolyte material can be used without reducing it, and the high ionic conductivity of the first solid electrolyte material can be maintained more stably. As a result, the charge and discharge efficiency of the battery can be improved.

[0074] The negative electrode 203 contains a material capable of inserting and deintercalating metal ions (e.g., lithium ions). This material is, for example, a negative electrode active material (e.g., negative electrode active material particles 205).

[0075] Examples of negative electrode active materials include metallic materials, carbon materials, oxides, nitrides, tin compounds, or silicon compounds. Metallic materials can be elemental metals or alloys. Examples of metallic materials include lithium metal or lithium alloys. Examples of carbon materials include natural graphite, coke, graphitizable carbon, carbon fibers, spherical carbon, artificial graphite, or amorphous carbon. From a capacity density perspective, suitable examples of negative electrode active materials are silicon (Si), tin (Sn), silicon compounds, or tin compounds.

[0076] The negative electrode active material can also be selected based on the reduction resistance of the solid electrolyte material contained in the negative electrode 203. When the negative electrode 203 contains a first solid electrolyte material, a material that can insert and extract lithium ions at a voltage above 0.27V relative to lithium can also be used as the negative electrode active material. As long as the negative electrode active material is such a material, the reduction of the first solid electrolyte material contained in the negative electrode 203 can be suppressed. As a result, the battery has high charge and discharge efficiency. Examples of such negative electrode active materials are titanium oxide, indium metal, or lithium alloys. An example of titanium oxide is Li4Ti5O. 12 LiTi2O4 or TiO2.

[0077] The negative electrode active material particles 205 can also have a median particle size of 0.1 μm or larger and 100 μm or smaller. When the negative electrode active material particles 205 have a median particle size of 0.1 μm or larger, the negative electrode active material particles 205 and the solid electrolyte particles 100 can be well dispersed in the negative electrode 203. As a result, the charge and discharge characteristics of the battery are improved. When the negative electrode active material particles 205 have a median particle size of 100 μm or smaller, the lithium diffusion rate within the negative electrode active material particles 205 is increased. As a result, the battery can operate at high output power.

[0078] The negative electrode active material particles 205 can also have a larger median particle size than the solid electrolyte particles 100. Therefore, the negative electrode active material particles 205 and the solid electrolyte particles 100 can be well dispersed.

[0079] In order to improve the energy density and output power of the battery, in the negative electrode 203, the ratio of the volume of the negative electrode active material particles 205 to the total volume of the negative electrode active material particles 205 and the solid electrolyte particles 100 can also be 0.30 or higher and 0.95 or lower.

[0080] Figure 2 The electrode material 1100 shown may, for example, be contained in the negative electrode 203. To prevent the electrode active material particles 206 (i.e., the negative electrode active material) from reacting with the solid electrolyte particles 100, a coating layer 216 may also be formed on the surface of the electrode active material particles 206. As a result, the battery has high charge and discharge efficiency. Examples of coating materials contained in the coating layer 216 include sulfide solid electrolytes, oxide solid electrolytes, polymer solid electrolytes, or halide solid electrolytes.

[0081] When the solid electrolyte particle 100 is the first solid electrolyte material, the coating material may also contain sulfide solid electrolytes, oxide solid electrolytes, or polymeric solid electrolytes. An example of a sulfide solid electrolyte is Li₂S-P₂S₅. An example of an oxide solid electrolyte is lithium triphosphate. An example of a polymeric solid electrolyte is a composite compound of polyethylene oxide and lithium salt. An example of such a polymeric solid electrolyte is lithium bis(trifluoromethanesulfonyl)imide.

[0082] To improve the energy density and output power of the battery, the negative electrode 203 can also have a thickness of more than 10 μm and less than 500 μm.

[0083] At least one of the cathode 201, electrolyte layer 202, and anode 203 may also contain a second solid electrolyte material for the purpose of improving ion conductivity. Examples of the second solid electrolyte material are sulfide solid electrolytes, oxide solid electrolytes, halide solid electrolytes, or organic polymer solid electrolytes.

[0084] In this disclosure, "sulfide solid electrolyte" means a solid electrolyte containing sulfur. "Oxide solid electrolyte" means a solid electrolyte containing oxygen. Oxide solid electrolytes may also contain anions other than oxygen (however, sulfide anions and halide anions are excluded). "Halide solid electrolyte" means a solid electrolyte containing halogens and substantially free of sulfur. Halide solid electrolytes may contain not only halogens but also oxygen.

[0085] Examples of sulfide solid electrolytes include Li₂S-P₂S₅, Li₂S-SiS₂, Li₂S-B₂S₃, Li₂S-GeS₂, and Li₂S-P₂S₅. 3.25 Ge 0.25 P 0.75 S4 or Li 10 GeP2S 12 .

[0086] Examples of oxide solid electrolytes are:

[0087] (i) NASICON-type solid electrolytes such as LiTi2(PO4)3 or its elemental substitutes;

[0088] (ii) Perovskite-type solid electrolytes such as (LaLi)TiO3,

[0089] (iii)Li 14 ZnGe4O 16 LISICON-type solid electrolytes such as Li4SiO4, LiGeO4, or their elemental substitutes.

[0090] (iv)Li7La3Zr2O 12 Garnet-type solid electrolytes such as or elemental substitutes thereof, or (v)Li3PO4 or its N-substitutes thereof.

[0091] An example of a halide solid electrolyte is the use of Li a Me' b Y c Z6 represents the compound. Here, it satisfies the mathematical formula: a + mb + 3c = 6 and c > 0. Me' is at least one metallic element and half-metallic element selected from those other than Li and Y. Z is at least one selected from F, Cl, Br, and I. The value of m represents the valence of Me'.

[0092] The “semi-metallic elements” are B, Si, Ge, As, Sb, and Te.

[0093] "Metallic elements" refers to all elements contained in Groups 1 to 12 of the periodic table (except hydrogen) and all elements contained in Groups 13 to 16 of the periodic table (except B, Si, Ge, As, Sb, Te, C, N, P, O, S and Se).

[0094] To improve the ionic conductivity of halide solid electrolytes, Me' may also be at least one selected from Mg, Ca, Sr, Ba, Zn, Sc, Al, Ga, Bi, Zr, Hf, Ti, Sn, Ta, and Nb.

[0095] Examples of halide solid electrolytes are Li3YCl6 or Li3YBr6.

[0096] When the electrolyte layer 202 contains the first solid electrolyte material, the negative electrode 203 can also contain a sulfide solid electrolyte. Thus, the sulfide solid electrolyte, which is electrochemically stable relative to the negative electrode active material, can suppress the mutual contact between the first solid electrolyte material and the negative electrode active material. As a result, the battery has low internal resistance.

[0097] Examples of organic polymer solid electrolytes include polymeric compounds and lithium salt compounds. Polymers can also have an ethylene oxide structure. Polymers with an ethylene oxide structure exhibit higher ionic conductivity because they can contain more lithium salts.

[0098] Examples of lithium salts include LiPF6, LiBF4, LiSbF6, LiAsF6, LiSO3CF3, LiN(SO2CF3)2, LiN(SO2C2F5)2, LiN(SO2CF3)(SO2C4F9), or LiC(SO2CF3)3. A single lithium salt selected from these can be used. Alternatively, a mixture of two or more lithium salts selected from these can be used.

[0099] The electrolyte may be selected from at least one of the positive electrode 201, electrolyte layer 202 and negative electrode 203, and may also contain a non-aqueous electrolyte, gel electrolyte or ionic liquid for the purpose of facilitating the acceptance of lithium ions and improving the output power characteristics of the battery.

[0100] The non-aqueous electrolyte contains a non-aqueous solvent and a lithium salt dissolved in that non-aqueous solvent. Examples of non-aqueous solvents include cyclic carbonate solvents, chain carbonate solvents, cyclic ether solvents, chain ether solvents, cyclic ester solvents, chain ester solvents, or fluorinated solvents. Examples of cyclic carbonate solvents include ethylene carbonate, propylene carbonate, or butyl carbonate. Examples of chain carbonate solvents include dimethyl carbonate, methyl ethyl carbonate, or diethyl carbonate. Examples of cyclic ether solvents include tetrahydrofuran, 1,4-dioxane, or 1,3-dioxapentane. Examples of chain ether solvents include 1,2-dimethoxyethane or 1,2-diethoxyethane. Examples of cyclic ester solvents include γ-butyrolactone. Examples of chain ester solvents include methyl acetate. Examples of fluorinated solvents include fluoroethylene carbonate, methyl fluoropropionate, fluorobenzene, methyl ethyl fluorocarbonate, or dimethyl fluorocarbonate. One of these non-aqueous solvents may also be used alone. Alternatively, a mixture of two or more non-aqueous solvents can be used.

[0101] Examples of lithium salts include LiPF6, LiBF4, LiSbF6, LiAsF6, LiSO3CF3, LiN(SO2CF3)2, LiN(SO2C2F5)2, LiN(SO2CF3)(SO2C4F9), or LiC(SO2CF3)3. A single lithium salt selected from these can be used. Alternatively, a mixture of two or more lithium salts selected from these can be used. The concentration of the lithium salt is, for example, in the range of 0.5 mol / L or more and 2 mol / L or less.

[0102] As a gel electrolyte, a polymeric material impregnated with a non-aqueous electrolyte can be used. Examples of polymeric materials include polyethylene oxide, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, or polymers containing ethylene oxide bonds.

[0103] Examples of cations contained in ionic liquids are:

[0104] (i) Aliphatic chain quaternary salts such as tetraalkylammonium or tetraalkylphosphonium;

[0105] (ii) Aliphatic cyclic ammonium compounds such as pyrrolidinemonium, morpholinium, imidazolinemonium, tetrahydropyrimidinemonium, piperazinemonium, or piperidinemonium, or

[0106] (iii) Nitrogen-containing heterocyclic aromatic cations such as pyridinium or imidazoline.

[0107] An example of anion contained in ionic liquids is PF6. - BF4 - SbF6 - AsF6 - SO3CF3 - N(SO2CF3)2 - N(SO2C2F5)2 - N(SO2CF3)(SO2C4F9) - Or C(SO2CF3)3 - .

[0108] Ionic liquids can also contain lithium salts.

[0109] The electrode is selected from at least one of the positive electrode 201, electrolyte layer 202 and negative electrode 203, and may also contain a binder to improve the adhesion between particles.

[0110] Examples of adhesives include polyvinylidene fluoride, polytetrafluoroethylene, polyethylene, polypropylene, aromatic polyamide resins, polyamides, polyimides, polyamide-imides, polyacrylonitrile, polyacrylic acid, polymethyl methacrylate, polyethyl methacrylate, polyhexyl methacrylate, polymethacrylic acid, polymethyl methacrylate, polyethyl methacrylate, polyhexyl methacrylate, polyvinyl acetate, polyvinylpyrrolidone, polyether, polyethersulfone, polyhexafluoropropylene, styrene-butadiene rubber, or carboxymethyl cellulose. Copolymers may also be used as adhesives. Examples of such adhesives are copolymers selected from two or more materials chosen from tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, perfluoroalkyl vinyl ethers, vinylidene fluoride, trifluorochloroethylene, ethylene, propylene, pentafluoropropylene, fluoromethyl vinyl ether, acrylic acid, and hexadiene. Mixtures of two or more materials selected from the above materials may also be used.

[0111] At least one of the positive electrode 201 and the negative electrode 203 may also contain a conductive additive to improve electronic conductivity.

[0112] Examples of conductive additives are:

[0113] (i) Graphite, such as natural or artificial graphite;

[0114] (ii) Carbon blacks such as acetylene black or Ketjen black;

[0115] (iii) Conductive fibers such as carbon fiber or metal fiber;

[0116] (iv) Fluorocarbon,

[0117] (v) Metal powders such as aluminum

[0118] (vi) Conductive whiskers such as zinc oxide or potassium titanate;

[0119] (vii) Conductive metal oxides such as titanium dioxide, or

[0120] (viii) Conductive polymers such as polyaniline, polypyrrole, or polythiophene. For cost reduction, conductive additives described in (i) or (ii) above may also be used.

[0121] Examples of the battery shape in the second embodiment include coin shape, cylindrical shape, square shape, sheet shape, button shape, flat shape, or stacked shape.

[0122] The battery of the second embodiment can also be manufactured by preparing materials for forming a positive electrode, materials for forming an electrolyte layer, and materials for forming a negative electrode, and then using known methods to create a laminate in which a positive electrode, an electrolyte layer, and a negative electrode are sequentially arranged.

[0123] Example

[0124] The present disclosure will now be described in more detail using examples.

[0125] (Example 1)

[0126] [Preparation of Solid Electrolyte Materials]

[0127] In a dry atmosphere with a dew point below -30°C (hereinafter referred to as "dry atmosphere"), Li₂O₂, TaCl₅, and AlCl₃ were prepared as raw material powders in a molar ratio of 1:1.8:0.2 of Li₂O₂:TaCl₅:AlCl₃. These materials were pulverized and mixed in a mortar to obtain a mixture. The resulting mixture was then ground at 600 rpm for 24 hours using a planetary ball mill (Fritsch P-7 model). This yielded the powder of the solid electrolyte material of Example 1.

[0128] [Evaluation of Ion Conductivity]

[0129] Figure 3 A schematic diagram of a pressure forming mold 300 used to evaluate the ionic conductivity of solid electrolyte materials.

[0130] The pressure forming die 300 includes an upper punch 301, a frame die 302, and a lower punch 303. The frame die 302 is formed of insulating polycarbonate. The upper punch 301 and the lower punch 303 are both formed of electronically conductive stainless steel.

[0131] use Figure 3 The ionic conductivity of the solid electrolyte material of Example 1 was measured using the pressure molding die 300 shown in the following method.

[0132] In a dry atmosphere, the powder of the solid electrolyte material of Example 1 is filled into the interior of the pressure forming mold 300. Inside the pressure forming mold 300, the upper part 301 and the lower part 303 of the punch are used to press the solid electrolyte material of Example 1 (i.e., Figure 3 The powder 101 of the solid electrolyte material in the middle is subjected to a pressure of 300 MPa.

[0133] While maintaining the applied pressure, the upper part 301 and the lower part 303 of the punch were connected to a potentiostat (Versa STAT4 manufactured by Princeton Applied Research) equipped with a frequency response analyzer. The upper part 301 of the punch was connected to the working electrode and the potential measurement terminal. The lower part 303 of the punch was connected to the counter electrode and the reference electrode. The ionic conductivity of the solid electrolyte material of Example 1 was measured at room temperature by electrochemical impedance spectroscopy. The result showed that the ionic conductivity measured at 22°C was 4.2 mS / cm.

[0134] X-ray diffraction measurement

[0135] Figure 4A These are X-ray diffraction patterns of the solid electrolyte materials of Examples 1-7. The X-ray diffraction patterns were determined using the methods described below.

[0136] The X-ray diffraction pattern of the solid electrolyte material of Example 1 was determined using an X-ray diffraction apparatus (RIGAKU MiniFlex600) in a dry atmosphere with a dew point below -45°C. Cu-Kα rays (wavelength...) were used as the X-ray source. and ).

[0137] The solid electrolyte material of Example 1 has a peak at 12.50°.

[0138] [Battery Manufacturing]

[0139] The solid electrolyte material and the positive electrode active material, LiCoO2, of Example 1 were prepared in an argon atmosphere with a dew point below -60°C at a volume ratio of 50:50. These materials were mixed in a mortar to obtain a positive electrode mixture.

[0140] In an insulating cylinder with an inner diameter of 9.5 mm, the solid electrolyte material (120 mg) of Example 1 and the above-described positive electrode mixture (10.6 mg) are stacked to obtain a laminate. A pressure of 360 MPa is applied to the laminate to form a solid electrolyte layer and a positive electrode. The solid electrolyte layer has a thickness of 500 μm.

[0141] Next, a Li-In alloy with a thickness of 200 μm is stacked on the solid electrolyte layer. A pressure of 80 MPa is applied to the stack to form the negative electrode.

[0142] A current collector made of stainless steel is installed on the positive and negative terminals, and current collection leads are installed on the current collector.

[0143] Finally, an insulating hoop is used to isolate the inside of the insulating cylinder from the external atmosphere, thus sealing the inside of the cylinder.

[0144] This yields the battery of Example 1.

[0145] [Charge / Discharge Test]

[0146] Figure 6 This is a graph representing the initial discharge characteristics of the battery in Example 1. The initial discharge characteristics were measured using the following method.

[0147] The battery in Example 1 was placed in a constant temperature bath at 25°C.

[0148] The battery of Example 1 was charged to a voltage of 3.6V at a current of 56μA. This current density corresponds to a rate of 0.05C.

[0149] Next, the battery was discharged at a current of 56μA until it reached a voltage of 1.9V.

[0150] The battery in Example 1 was charged and discharged at room temperature.

[0151] The results of the charge-discharge test showed that the battery in Example 1 had an initial discharge capacity of 1.06 mAh.

[0152] (Examples 2-9 and Comparative Examples 1-2)

[0153] [Preparation of Solid Electrolyte Materials]

[0154] In Example 2, Li2O2, TaCl5, and AlCl3 were prepared as raw material powders in a molar ratio of 1:1.8:0.2 (Li2O2:TaCl5:AlCl3). After grinding the mixture, it was calcined at 200°C for 3 hours.

[0155] In Example 3, Li2O2, TaCl5 and AlCl3 were prepared as raw material powders in a molar ratio of Li2O2:TaCl5:AlCl3 of 1:1.2:0.8.

[0156] In Example 4, Li2O2, TaCl5, and AlCl3 were prepared as raw material powders in a molar ratio of 1:1.2:0.8 of Li2O2:TaCl5:AlCl3. After grinding the mixture, it was calcined at 200°C for 3 hours.

[0157] In Example 5, Li2O2, TaCl5 and AlCl3 were prepared as raw material powders in a molar ratio of Li2O2:TaCl5:AlCl3 of 1:0.8:1.2.

[0158] In Example 6, Li2O2, TaCl5, and AlCl3 were prepared as raw material powders in a molar ratio of 1:0.8:1.2 of Li2O2:TaCl5:AlCl3. After grinding the mixture, it was calcined at 200°C for 3 hours.

[0159] In Example 7, Li2O2, TaCl5, AlCl3, and TaF5 were prepared as raw material powders in a molar ratio of 1:1.7:0.2:0.1 of Li2O2:TaCl5:AlCl3:TaF5. After grinding the mixture, it was calcined at 200°C for 3 hours.

[0160] In Example 8, Li2O2, NbCl5 and AlCl3 were prepared as raw material powders in a molar ratio of Li2O2:NbCl5:AlCl3 of 1:1.2:0.8.

[0161] In Example 9, Li2O2, NbCl5, and AlCl3 were prepared as raw material powders in a molar ratio of 1:1.2:0.8 of Li2O2:NbCl5:AlCl3. After grinding the mixture, it was calcined at 80°C for 3 hours.

[0162] In Comparative Example 1, Li2O2 and LiCl were prepared as raw material powders in a manner that achieved a Li2O2:LiCl molar ratio of 1:1.

[0163] In Comparative Example 2, LiCl and TaCl5 were prepared as raw material powders in a 1:1 molar ratio of LiCl to TaCl5.

[0164] Except as described above, the solid electrolyte materials of Examples 2 to 9, Comparative Example 1 and Comparative Example 2 were obtained in the same manner as in Example 1.

[0165] [Evaluation of Ion Conductivity]

[0166] The ionic conductivity of the solid electrolyte materials of Examples 2-9, Comparative Examples 1 and 2 was measured in the same manner as in Example 1. The measurement results are shown in Table 1.

[0167] X-ray diffraction

[0168] The X-ray diffraction patterns of the solid electrolyte materials of Examples 2-9, Comparative Example 1 and Comparative Example 2 were measured in the same manner as in Example 1. Figure 4A This is a diagram showing the X-ray diffraction patterns of the solid electrolyte materials in Examples 1 to 7. Figure 4B This is a diagram showing the X-ray diffraction patterns of the solid electrolyte materials of Examples 8 and 9. Figure 5 This is a diagram showing the X-ray diffraction patterns of the solid electrolyte materials of Comparative Examples 1 and 2.

[0169] The solid electrolyte material of Example 2 has a peak at 11.13°.

[0170] The solid electrolyte material of Example 3 has a peak at 12.52°.

[0171] The solid electrolyte material of Example 4 has a peak at 15.53°.

[0172] The solid electrolyte material of Example 5 does not have a peak in the first range.

[0173] The solid electrolyte material of Example 6 has a peak at 15.55°.

[0174] The solid electrolyte material of Example 7 has a peak at 11.15°.

[0175] The solid electrolyte material of Example 8 has a peak at 14.29°.

[0176] The solid electrolyte material of Example 9 has a peak at 13.84°.

[0177] Comparative Example 1 and Comparative Example 2 do not have peaks in the first range.

[0178] Table 1

[0179]

[0180] (Inspection)

[0181] Table 1 shows that the solid electrolyte materials of Examples 1-9 have a temperature range of 1×10⁻⁶ at around room temperature. 3 High ionic conductivity exceeding mS / cm. Additionally, it possesses a conductivity of 1×10⁻⁶ mS / cm. 2 High ionic conductivity above mS / cm.

[0182] The comparison between Examples 1-4 and Examples 5 and 6 shows that as long as the ratio of the amount of Al to the total amount of M and Al is 10% or more and 40% or less, the ionic conductivity of the solid electrolyte material is further improved.

[0183] The comparison between Examples 3 and 4 and Examples 8 and 9 shows that when M is Nb, the ionic conductivity of the solid electrolyte material is further improved when M is Ta.

[0184] The solid electrolyte materials in Examples 1-9 did not produce hydrogen sulfide because they did not contain sulfur.

[0185] As described above, the solid electrolyte material of this disclosure is suitable for providing batteries with excellent charge-discharge characteristics due to its practical lithium-ion conductivity.

[0186] Industrial availability

[0187] The battery disclosed herein can be used, for example, in all-solid-state lithium-ion secondary batteries.

Claims

1. A solid electrolyte material, which is substantially composed of Li, M, Al, O and X. M is selected from at least one of Ta and Nb. X is selected from at least one of F, Cl and Br. The crystalline phase containing peaks in the X-ray diffraction pattern obtained by using Cu-Kα rays, within a diffraction angle range of 2θ above 11.08° and below 15.63°. Here, the phrase "substantially composed of Li, M, Al, O and X" means that the total amount of Li, M, Al, O and X is greater than or equal to the total amount of all elements constituting the solid electrolyte material.

2. The solid electrolyte material according to claim 1, wherein, X is selected from at least one of Cl and Br.

3. The solid electrolyte material according to claim 1, wherein, M represents Ta.

4. The solid electrolyte material of claim 1, wherein, The ratio of the amount of Al to the total amount of M and Al is more than 5 mol% and less than 70 mol%.

5. The solid electrolyte material according to claim 4, wherein, The ratio of the amount of Al to the total amount of M and Al is 10 mol% or more and 70 mol% or less.

6. The solid electrolyte material according to claim 5, wherein, The ratio of the amount of Al to the total amount of M and Al is 10 mol% or more and 60 mol% or less.

7. A battery, wherein, have: positive electrode, Negative electrode, and An electrolyte layer disposed between the positive electrode and the negative electrode; The material is selected from at least one of the solid electrolyte materials contained in any one of claims 1 to 6, including the positive electrode, the negative electrode, and the electrolyte layer.

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