阅读说明：本技术 电解质材料及使用它的电池 (Electrolyte material and battery using the same ) 是由 西尾勇祐 酒井章裕 浅野哲也 境田真志 宫崎晃畅 于 2020-02-14 设计创作，主要内容包括：本公开提供一种具有高的锂离子传导率的电解质材料。本公开的电解质材料由Li-(4-3a-)-(cb)Al-aM-bF-xCl-yBr-(4-x-y)表示。在此,M是选自Mg、Ca和Zr中的至少1种,c表示M的价数,且满足以下的5个数学式：0<a<1.33、0≤b<2、0<x<4、0≤y<4、和(x+y)≤4。(The present disclosure provides aAn electrolyte material having high lithium ion conductivity. The electrolyte material of the present disclosure is made of Li 4‑3a‑cb Al a M b F x Cl y Br 4‑x‑y And (4) showing. Here, M is at least 1 selected from Mg, Ca and Zr, c represents the valence of M and satisfies the following 5 formulae: 0<a<1.33、0≤b<2、0<x<4、0≤y<4. And (x + y) is less than or equal to 4.)

1. An electrolyte material represented by the following composition formula (1),

Li_4-3a-cbAl_aM_bF_xCl_yBr_4-x-y(1)

here, M is at least 1 selected from Mg, Ca and Zr, c represents the valence of M and satisfies the following 5 numerical formulae:

0<a<1.33、

0≤b<2、

0<x<4、

0< y <4, and

(x+y)≤4。

2. the electrolyte material of claim 1 wherein,

x is more than or equal to 0.4 and less than or equal to 2.0.

3. The electrolyte material of claim 2 wherein,

x is more than or equal to 0.8 and less than or equal to 1.8.

4. The electrolyte material according to any one of claims 1 to 3, wherein,

a is more than or equal to 1 and less than or equal to 1.25.

5. The electrolyte material of claim 4 wherein,

a is more than or equal to 1 and less than or equal to 1.2.

6. A battery comprising a positive electrode, a negative electrode and an electrolyte layer,

the electrolyte layer is disposed between the positive electrode and the negative electrode,

at least 1 selected from the group consisting of the positive electrode, the negative electrode and the electrolyte layer contains the electrolyte material according to any one of claims 1 to 5.

7. The battery according to claim 6, wherein,

the electrolyte layer contains a nonaqueous electrolyte solution and the electrolyte material according to any one of claims 1 to 5.

Technical Field

The present disclosure relates to an electrolyte material and a battery using the same.

Background

Patent document 1 discloses an all-solid battery using a sulfide solid electrolyte. Non-patent documents 1 and 2 disclose the use of LiAlCl₄The battery of (1).

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2011-129312

Non-patent document

Non-patent document 1: J.electrochem.SOC.35, 124, (1977)

Non-patent document 2: J.electrochem.SOC.1509, 139, (1992)

Disclosure of Invention

Problems to be solved by the invention

An object of the present disclosure is to provide an electrolyte material having high lithium ion conductivity.

Means for solving the problems

The electrolyte material of the present disclosure is a material represented by the following composition formula (1).

Li_4-3a-cbAl_aM_bF_xCl_yBr_4-x-y (1)

Here, M is at least one element selected from Mg, Ca and Zr, c represents the valence of M and satisfies the following 5 numerical formulae: 0< a <1.33, 0< b <2, 0< x <4, 0< y <4, and (x + y) < 4.

Effects of the invention

The present disclosure provides an electrolyte material having high lithium ion conductivity.

Drawings

Fig. 1 shows a cross-sectional view of a battery 1000 of embodiment 2.

Fig. 2 shows a schematic view of a press-forming die 300 used for evaluating the ionic conductivity of an electrolyte material.

Fig. 3 is a diagram of a Cole-Cole line graph showing the AC impedance measurement result of the electrolyte material of example 1.

Fig. 4 is a graph showing initial discharge characteristics of the batteries of example 1 and comparative example 1.

Detailed Description

Embodiments of the present disclosure will be described below with reference to the drawings.

(embodiment 1)

The electrolyte material of embodiment 1 is a material represented by the following composition formula (1).

Li_4-3a-cbAl_aM_bF_xCl_yBr_4-x-y…(1)

Here, M is at least 1 selected from Mg, Ca and Zr, c represents the valence of M and satisfies the following 5 formulae: 0< a <1.33, 0< b <2, 0< x <4, 0< y <4, and (x + y) < 4.

The electrolyte material of embodiment 1 has high lithium ion conductivity.

The electrolyte material according to embodiment 1 can be used to obtain a battery having excellent charge and discharge characteristics. An example of the battery is an all-solid secondary battery.

Since the electrolyte material according to embodiment 1 does not contain sulfur, hydrogen sulfide is not generated even when exposed to the atmosphere. Therefore, the electrolyte material of embodiment 1 is excellent in safety. Note that the sulfide solid electrolyte disclosed in patent document 1 generates hydrogen sulfide if exposed to the atmosphere.

In order to improve the ionic conductivity of the electrolyte material, 0.4. ltoreq. x.ltoreq.2.0 may be satisfied in formula (1). In order to further improve the ionic conductivity, 0.8. ltoreq. x.ltoreq.1.8 may be satisfied.

In order to improve the ionic conductivity of the electrolyte material, 1. ltoreq. a.ltoreq.1.25 may be satisfied in formula (1). In order to further improve the ionic conductivity, 1. ltoreq. a.ltoreq.1.2 may be satisfied.

To improve the ionic conductivity of the electrolyte material, M may be Zr.

In order to improve the ion conductivity of the electrolyte material, b ═ 0 may be satisfied. That is, the electrolyte material may be a material represented by the following composition formula (2).

Li_4-3aAl_aF_xCl_yBr_4-x-y…(2)

Here, the following 4 numerical expressions are satisfied: 0< a <1.33, 0< x <4, 0< y <4, and (x + y) < 4.

The electrolyte material of embodiment 1 may be crystalline or may be amorphous.

The shape of the electrolyte material of embodiment 1 is not limited. Examples of the shape of the electrolyte material of embodiment 1 are needle-like, spherical, or oval spherical. For example, the electrolyte material of embodiment 1 may be particles. The electrolyte material of embodiment 1 may be formed in a pellet or plate shape.

For example, in the case where the electrolyte material of embodiment 1 is in the form of particles (for example, spheres), the electrolyte material may have a median particle diameter of 0.1 μm or more and 100 μm or less. The electrolyte material of embodiment 1 may have a median particle diameter of 0.5 μm or more and 10 μm or less. Thus, the electrolyte material has higher ion conductivity. Further, the electrolyte material can be formed in a good dispersion state with other materials such as an active material.

< method for producing electrolyte Material >

The electrolyte material of embodiment 1 is produced, for example, by the following method.

The raw powder of the halide is mixed in a manner having the target composition. For example, the target composition is LiAlF_1.6Cl_2.4In the case of (1), LiCl or AlCl is added₃And AlF₃Mixing the raw materials in a ratio of 1.0: 0.47: about 0.53 LiCl: AlCl₃：AlF₃Mixing the components according to the molar ratio. Or LiF, AlCl₃And AlF₃The ratio of 1.0: 0.8: about 0.2 LiF: AlCl₃：AlF₃Mixing the components according to the molar ratio. The raw powder may be mixed in a molar ratio adjusted in advance in such a manner as to offset a change in composition that may occur during synthesis.

The raw material powders are subjected to mechanochemical (i.e., a method using mechanochemical grinding) mutual reaction in a mixing apparatus such as a planetary ball mill to obtain a reactant. Alternatively, the reaction product can be obtained by firing a mixture of raw material powders in vacuum or in an inert atmosphere (for example, an argon atmosphere or a nitrogen atmosphere).

The electrolyte material of embodiment 1 is obtained by these methods.

(embodiment 2)

Embodiment 2 of the present disclosure will be described below. The matters already described in embodiment 1 are appropriately omitted.

The battery of embodiment 2 has 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 1 selected from the positive electrode, the electrolyte layer, and the negative electrode contains the electrolyte material of embodiment 1.

The battery of embodiment 2 contains the electrolyte material of embodiment 1, and therefore has excellent charge and discharge characteristics.

Fig. 1 shows a cross-sectional view of a battery 1000 of embodiment 2.

The battery 1000 of embodiment 2 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.

The positive electrode 201 includes positive electrode active material particles 204 and electrolyte particles 100.

The electrolyte layer 202 contains an electrolyte material (e.g., a solid electrolyte material).

The negative electrode 203 contains negative electrode active material particles 205 and electrolyte particles 100.

The electrolyte particles 100 are particles composed of the electrolyte material of embodiment 1 or particles containing the electrolyte material of embodiment 1 as a main component. The particles containing the electrolyte material of embodiment 1 as a main component mean particles whose content is the largest as the electrolyte material of embodiment 1.

The positive electrode 201 contains a material that can occlude or release metal ions (e.g., lithium ions). The positive electrode 201 contains, for example, a positive electrode active material (for example, positive electrode active material particles 204).

Examples of the positive electrode active material are lithium-containing transition metal oxides, transition metal fluorides, polyanionic materials, fluorinated polyanionic materials, transition metal sulfides, transition metal oxyfluorides, transition metal oxysulfides, or transition metal oxynitrides. Examples of lithium-containing transition metal oxides are Li (NiCoAl) O₂Or LiCoO₂。

The positive electrode active material particles 204 may have a median particle diameter of 0.1 μm or more and 100 μm or less. When the positive electrode active material particles 204 have a median particle diameter of 0.1 μm or more, the positive electrode active material particles 204 and the electrolyte particles 100 can be dispersed well in the positive electrode. This improves the charge/discharge characteristics of the battery. When the positive electrode active material particles 204 have a median particle diameter of 100 μm or less, the lithium diffusion rate in the positive electrode active material particles 204 increases. Thereby, the battery can be operated with high output power.

The positive electrode active material particles 204 may have a larger median particle diameter than the electrolyte particles 100. This enables the positive electrode active material particles 204 and the electrolyte particles 100 to be dispersed well.

In the positive electrode 201, the ratio of the volume of the positive electrode active material particles 204 to the total of the volume of the positive electrode active material particles 204 and the volume of the electrolyte particles 100 may be 0.30 or more and 0.95 or less from the viewpoint of the energy density and the output of the battery.

The positive electrode 201 may have a thickness of 10 μm or more and 500 μm or less from the viewpoint of energy density and output of the battery.

The electrolyte material contained in the electrolyte layer 202 may be the electrolyte material of embodiment 1.

The electrolyte layer 202 may be a solid electrolyte layer.

The electrolyte layer 202 may be composed of only the electrolyte material of embodiment 1.

The electrolyte layer 202 may be composed of only an electrolyte material (for example, a solid electrolyte material) different from the electrolyte material of embodiment 1. An example of an electrolyte material different from that of embodiment 1 is Li₂MgX₄、Li₂FeX₄、Li(Ga，In)X₄、Li₃(Y，Gd，Sm，Al，Ga，In)X₆、Li₂ZrX₆Or LiI. Here, X is at least 1 element selected from F, Cl, Br and I.

The electrolyte material of embodiment 1 will be referred to as the 1 st electrolyte material hereinafter. An electrolyte material different from the electrolyte material of embodiment 1 is referred to as a 2 nd electrolyte material.

The electrolyte layer 202 may contain not only the 1 st electrolyte material but also the 2 nd electrolyte material. In the electrolyte layer 202, the 1 st electrolyte material and the 2 nd electrolyte material may be uniformly dispersed.

The layer composed of the 1 st electrolyte material and the layer composed of the 2 nd electrolyte material may be laminated in the lamination direction of the battery 1000.

The electrolyte layer 202 may have a thickness of 1 μm or more and 100 μm or less. When the electrolyte layer 202 has a thickness of 1 μm or more, the positive electrode 201 and the negative electrode 203 are less likely to be short-circuited. In the case where the electrolyte layer 202 has a thickness of 100 μm or less, the battery can operate at high output.

The negative electrode 203 contains a material that can occlude and release metal ions (e.g., lithium ions). The negative electrode 203 contains, for example, a negative electrode active material (for example, negative electrode active material particles 205).

Examples of the negative electrode active material are a metal material, a carbon material, an oxide, a nitride, a tin compound, or a silicon compound. The metallic material may be only one metal or may be an alloy. Examples of the metallic material are lithium metal or lithium alloy. Examples of carbon materials are natural graphite, coke, incompletely graphitized carbon, carbon fibers, spherical carbon, artificial graphite, or amorphous carbon. From the viewpoint of capacity density, preferable examples of the negative electrode active material are silicon (i.e., Si), tin (i.e., Sn), a silicon compound, or a tin compound.

The negative electrode active material particles 205 may have a median particle diameter of 0.1 μm or more and 100 μm or less. In the case where the negative electrode active material particles 205 have a median particle diameter of 0.1 μm or more, the negative electrode active material particles 205 and the electrolyte particles 100 can be well dispersed in the negative electrode 203. This improves the charge/discharge characteristics of the battery. When the negative electrode active material particles 205 have a median particle diameter of 100 μm or less, the lithium diffusion rate in the negative electrode active material particles 205 increases. Thereby, the battery can operate with high output.

The negative electrode active material particles 205 may have a larger median particle diameter than the electrolyte particles 100. This allows the negative electrode active material particles 205 and the electrolyte particles 100 to be dispersed well.

In the negative electrode 203, the ratio of the volume of the negative electrode active material particles 205 to the total of the volume of the negative electrode active material particles 205 and the volume of the electrolyte particles 100 may be 0.30 or more and 0.95 or less from the viewpoint of the energy density and the output of the battery.

The negative electrode 203 may have a thickness of 10 μm or more and 500 μm or less from the viewpoint of energy density and output of the battery.

At least 1 selected from the positive electrode 201, the electrolyte layer 202, and the negative electrode 203 may contain a 2 nd electrolyte material (e.g., a solid electrolyte material) for the purpose of improving ion conductivity, chemical stability, and electrochemical stability.

The 2 nd electrolyte material may be a sulfide solid electrolyte.

An example of a sulfide solid electrolyte is Li₂S-P₂S₅、Li₂S-SiS₂、Li₂S-B₂S₃、Li₂S-GeS₂、Li_3.25Ge_0.25P_0.75S₄Or Li₁₀GeP₂S₁₂。

The 2 nd electrolyte material may be an oxide solid electrolyte.

Examples of oxide solid electrolytes are:

(i)LiTi₂(PO₄)₃or an element-substituted form thereof, and a solid electrolyte of NASICON type,

(ii)(LaLi)TiO₃Perovskite-type solid electrolytes,

(iii)Li₁₄ZnGe₄O₁₆、Li₄SiO₄、LiGeO₄Or an element-substituted form thereof,

(iv)Li₇La₃Zr₂O₁₂Or an elemental substitution thereof, or

(v)Li₃PO₄Or its N-configured.

The 2 nd electrolyte material may be a halide solid electrolyte as described above.

An example of a halide solid electrolyte is Li₂MgX₄、Li₂FeX₄、Li(Ga，In)X₄、Li₃(Y，Gd，Sm，Al，Ga，In)X₆、Li₂ZrX₆Or LiI. Here, X is at least 1 element selected from F, Cl, Br, and I.

Other examples of halide solid electrolytes are made of Li_pMe_qY_rX’₆The compound shown in the specification. Here, p + mq +3r ═ 6, and c are satisfied>0. Me is at least 1 selected from metal elements and semimetal elements other than Li and Y. m represents the valence of Me. "half-metallic elements" are B, Si, Ge, As, Sb and Te. Metal element"is an element contained in all of groups 1 to 12 of the periodic table (wherein hydrogen is not included) and an element contained in all of groups 13 to 16 of the periodic table (wherein B, Si, Ge, As, Sb, Te, C, N, P, O, S, and Se are excluded).

From the viewpoint of ionic conductivity, Me is at least 1 element selected from the group consisting of Mg, Ca, Sr, Ba, Zn, Sc, Al, Ga, Bi, Zr, Hf, Ti, Sn, Ta and Nb. The halide solid electrolyte may be, for example, Li₃YCl₆Or Li₃YBr₆。

The 2 nd electrolyte material may be an organic polymer solid electrolyte.

Examples of the organic polymer solid electrolyte are a high molecular compound and a lithium salt compound. The polymer compound may have an ethylene oxide structure. Since the polymer compound having an ethylene oxide structure can contain a large amount of lithium salt, the ionic conductivity can be further improved.

An example of the lithium salt is LiPF₆、LiBF₄、LiSbF₆、LiAsF₆、LiSO₃CF₃、LiN(SO₂CF₃)₂、LiN(SO₂C₂F₅)₂、LiN(SO₂CF₃)(SO₂C₄F₉) Or LiC (SO)₂CF₃)₃. As the lithium salt, the electrolyte material of embodiment 1 may be used. 1 lithium salt selected from the exemplified lithium salts may be used alone. Alternatively, a mixture of 2 or more lithium salts selected from the exemplified lithium salts may be used.

At least 1 selected from the positive electrode 201, the electrolyte layer 202, and the negative electrode 203 may contain a nonaqueous electrolyte liquid, a gel electrolyte, or an ionic liquid for the purpose of facilitating the acceptance and administration of lithium ions and improving the output characteristics of the battery.

The nonaqueous electrolytic solution contains a nonaqueous solvent and a lithium salt dissolved in the nonaqueous solvent.

Examples of the nonaqueous solvent include a cyclic carbonate solvent, a chain carbonate solvent, a cyclic ether solvent, a chain ether solvent, a cyclic ester solvent, a chain ester solvent, or a fluorine solvent. Examples of the cyclic carbonate solvent are ethylene carbonate, propylene carbonate, or butylene carbonate. Examples of the chain carbonate solvent are dimethyl carbonate, ethyl methyl carbonate, or diethyl carbonate. Examples of cyclic ether solvents are tetrahydrofuran, 1, 4-dioxane, or 1, 3-dioxolane. Examples of the chain ether solvent are 1, 2-dimethoxyethane or 1, 2-diethoxyethane. An example of a cyclic ester solvent is gamma-butyrolactone. An example of the chain ester solvent is methyl acetate. Examples of fluorosolvents are fluoroethylene carbonate, methyl fluoropropionate, fluorobenzene, ethylmethyl fluorocarbonate, or fluorodimethylene carbonate. 1 kind of nonaqueous solvent selected from them can be used alone. Alternatively, a combination of 2 or more kinds of nonaqueous solvents selected from them may be used.

An example of the lithium salt is LiPF₆、LiBF₄、LiSbF₆、LiAsF₆、LiSO₃CF₃、LiN(SO₂CF₃)₂、LiN(SO₂C₂F₅)₂、LiN(SO₂CF₃)(SO₂C₄F₉) Or LiC (SO)₂CF₃)₃. The electrolyte material of embodiment 1 may be used as the lithium salt. 1 lithium salt selected from the exemplified lithium salts may be used alone. Alternatively, a mixture of 2 or more lithium salts selected from the exemplified lithium salts may be used. The concentration of the lithium salt is, for example, 0.5 mol/liter or more and 2 mol/liter or less.

In the battery of embodiment 2, the electrolyte layer 202 may contain a nonaqueous electrolytic solution containing the electrolyte material of embodiment 1. That is, the nonaqueous electrolytic solution contained in the electrolyte layer 202 may contain a nonaqueous solvent and the electrolyte material of embodiment 1 dissolved in the nonaqueous solvent. Such a battery has high oxidation resistance.

As the gel electrolyte, a polymer material impregnated with a nonaqueous electrolytic solution can be used. Examples of polymer materials are polyethylene oxide, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, or polymers having ethylene oxide bonds.

Examples of anions contained in ionic liquids are:

(i) aliphatic linear quaternary salts such as tetraalkylammonium and tetraalkylphosphonium,

(ii) Aliphatic cyclic ammonium such as pyrrolidinium, morpholinium, imidazolinium, tetrahydropyrimidinium, piperazinium or piperidinium, or

(iii) Nitrogen-containing heterocyclic aromatic cations such as pyridinium or imidazolium.

Examples of anions contained in ionic liquids are PF₆ ^-、BF₄ ^-、SbF_6- ^-、AsF₆ ^-、SO₃CF₃ ^-、N(SO₂CF₃)₂ ^-、N(SO₂C₂F₅)₂ ^-、N(SO₂CF₃)(SO₂C₄F₉)^-Or C (SO)₂CF₃)₃ ^-。

The ionic liquid may contain a lithium salt. As the lithium salt, the electrolyte material of embodiment 1 may be used.

At least 1 selected from the positive electrode 201, the electrolyte layer 202, and the negative electrode 203 may contain a binder for the purpose of improving adhesion between particles.

Examples of binders are polyvinylidene fluoride, polytetrafluoroethylene, polyethylene, polypropylene, aramid resins, polyamides, polyimides, polyamideimides, polyacrylonitrile, polyacrylic acid, polymethyl acrylate, polyethyl acrylate, polyhexamethylene acrylate, polymethacrylic acid, polymethyl methacrylate, polyethyl methacrylate, polyhexamethylene methacrylate, polyvinyl acetate, polyvinylpyrrolidone, polyethers, polyether sulfones, hexafluoropropylene, styrene-butadiene rubber or carboxymethylcellulose. The copolymers can also be used as binders. Examples of such binders include copolymers of 2 or more materials selected from tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, perfluoroalkyl vinyl ether, vinylidene fluoride, chlorotrifluoroethylene, ethylene, propylene, pentafluoropropylene, fluoromethyl vinyl ether, acrylic acid, and hexadiene. A mixture of 2 or more selected from the above materials may be used.

At least 1 selected from the positive electrode 201 and the negative electrode 203 may contain a conductive assistant for the purpose of improving electron conductivity.

Examples of the conductive assistant are:

(i) graphite such as natural graphite or artificial graphite,

(ii) Carbon blacks such as acetylene black and ketjen black,

(iii) Conductive fibers such as carbon fibers or metal fibers,

(iv) Carbon fluoride,

(v) Metal powders such as aluminum,

(vi) Conductive whiskers such as zinc oxide and potassium titanate,

(vii) A conductive metal oxide such as titanium oxide, or

(viii) And conductive polymer compounds such as polyaniline, polypyrrole, and polythiophene.

For cost reduction, the conductive auxiliary agent (i) or (ii) may be used.

Examples of the shape of the battery according to embodiment 2 include a coin shape, a cylindrical shape, a square shape, a sheet shape, a button shape, a flat shape, and a laminated shape.

(examples)

The present disclosure is described in more detail below with reference to examples and comparative examples.

(example 1)

[ preparation of electrolyte Material ]

In an argon atmosphere having a dew point of-60 ℃ or lower (hereinafter referred to as "under a dry argon atmosphere"), as a raw powder, a powder having a dew point of LiCl: AlCl₃：AlF₃The molar ratio is 1.0: 0.87: preparation of LiCl and AlCl in 0.13 manner₃And AlF₃. These raw material powders were pulverized and mixed in a mortar. The resulting mixture was subjected to a milling treatment using a planetary ball mill at 15 hours and 500 rpm. In this way, a powder of the electrolyte material of example 1 was obtained. The electrolyte material of example 1 has LiAlF_0.4Cl_3.6The composition shown.

The contents of Li, Al, F, and Cl per unit weight in the entire electrolyte material of example 1 were measured. The Li and Al contents were measured by inductively coupled plasma atomic emission spectrometry (ICP-AES). The contents of F and Cl were determined by ion chromatography. Based on the obtained Li, Al, F, and Cl contents, Li: al: f: cl molar ratio. As a result, the electrolyte material of example 1 had a mass ratio of 1.0: 1.0: 0.4: 3.6 Li: al: f: cl molar ratio.

[ evaluation of ion conductivity ]

Fig. 2 shows a schematic view of a press-forming die 300 used for evaluating the ionic conductivity of an electrolyte material.

The press-molding die 300 includes a frame die 301, a lower punch 302, and an upper punch 303. The frame mold 301 is made of insulating polycarbonate. The lower punch 302 and the upper punch 303 are each made of an electrically conductive stainless steel.

The ion conductivity of the electrolyte material of example 1 was measured by the following method using a press molding die 300 shown in fig. 3.

In a dry argon atmosphere, the powder 101 of the electrolyte material of example 1 was filled into the inside of the press molding die 300. A pressure of 400MPa was applied to the electrolyte material of example 1 using the lower punch 302 and the upper punch 303.

The lower punch 302 and the upper punch 303 are connected to a potentiostat (Princeton Applied Research, VersaSTAT4) equipped with a frequency response analyzer in a state where pressure is Applied. The upper punch 303 is connected to the working electrode and the potential measuring terminal. The lower punch 302 is connected to a counter electrode and a reference electrode. The impedance of the electrolyte material of example 1 was measured at room temperature using an electrochemical impedance measurement method.

Fig. 3 is a diagram of a Cole-Cole line graph showing the AC impedance measurement result of the electrolyte material of example 1.

The real value of the impedance at the measurement point at which the absolute value of the phase of the complex impedance is the smallest in fig. 3 is regarded as the value of the impedance with respect to the ion conduction of the electrolyte material. The real value is referred to the arrow R shown in FIG. 3_SEUsing the impedance value, based onThe ion conductivity is calculated by equation (2).

σ＝(R_SE×S/t)^-1 (2)

Here, σ represents ion conductivity. S represents a contact area with the upper punch 303 of the electrolyte material (equal to a cross-sectional area of the hollow portion of the frame die 301 in fig. 2). R_SERepresents the impedance value of the electrolyte material in the impedance measurement. t represents the thickness of the electrolyte material (i.e., the thickness of the layer formed by the powder 101 of the electrolyte material in fig. 2).

The ionic conductivity of the electrolyte material of example 1, measured at 25 ℃, was 2.5 x 10^-5S/cm。

[ production of Battery ]

The electrolyte material of example 1 and LiCoO as a positive electrode active material were mixed in a dry argon atmosphere₂And (3) adding 50: a volume ratio of about 50 was prepared. These materials were mixed in an agate mortar. Thus, a mixture was obtained.

The electrolyte material of example 1, the mixture (9.6mg) described above, and aluminum powder (14.7mg) were stacked in this order in an insulating cylinder having an inner diameter of 9.5 mm. A pressure of 300MPa was applied to the laminate to form a solid electrolyte layer and a 1 st electrode. The solid electrolyte layer has a thickness of 700 μm.

Next, metal In (thickness 200 μm) was laminated on the solid electrolyte layer. A pressure of 80MPa was applied to the laminate to form a 2 nd electrode. The 1 st electrode is a positive electrode, and the 2 nd electrode is a negative electrode.

Next, current collectors made of stainless steel were attached to the 1 st electrode and the 2 nd electrode, and current collecting leads were attached to the current collectors.

Finally, the inside of the insulating tube is sealed by isolating the outside atmosphere from the inside of the insulating tube with an insulating ferrule. The battery of example 1 was obtained by such an operation.

[ Charge/discharge test ]

Fig. 4 is a graph showing the initial discharge characteristics of the battery of example 1. The initial charge-discharge characteristics were measured by the following methods.

The cell of example 1 was placed in a thermostatic bath at 25 ℃.

The battery of example 1 was charged to a voltage of 3.6V at a current value of 0.05C-rate.

Next, the battery of example 1 was discharged to a voltage of 1.9V at the same current value of 0.05C magnification.

The result of the charge and discharge test was that the battery of example 1 had an initial discharge capacity of 290 μ Ah.

(examples 2 to 32)

In examples 2 to 24, as a raw material powder, LiCl: AlCl₃：AlF₃The molar ratio is (4-3 a): (a-x/3): x/3 method prepares LiCl and AlCl₃And AlF₃。

In examples 25 to 29, as a raw material powder, LiBr: AlBr₃：AlF₃The molar ratio is (4-3 a): (a-x/3): preparation of LiBr and AlBr in the x/3 System₃And AlF₃。

In examples 30 to 32, as a raw material powder, a powder of LiCl: AlCl₃：AlBr₃：AlF₃The molar ratio is (4-3 a): { a + (y-4)/3 }: (4-x-y)/3: x/3 method prepares LiCl and AlCl₃、AlBr₃And AlF₃。

In examples 4, 6, 8, 15, 16, 18, 20, and 23, the mixture of raw material powders was ground using a planetary ball mill and then heat-treated at 150 ℃ for 30 minutes in a dry argon atmosphere.

Except for the above, electrolyte materials of examples 2 to 32 were obtained in the same manner as in example 1.

The values of a, b, x, and y for the electrolyte materials of examples 2 to 32 are shown in table 1.

The ion conductivity of the electrolyte materials of examples 2 to 32 was measured in the same manner as in example 1. The measurement results are shown in Table 1.

Batteries of examples 2 to 32 were obtained in the same manner as in example 1 using the electrolyte materials of examples 2 to 32. The batteries of examples 2 to 32 were used to perform a charge and discharge test in the same manner as in example 1. As a result, the batteries of examples 2 to 32 were charged and discharged well as in example 1.

Examples 33 to 50

In examples 33 to 40, as a raw material powder, LiCl: AlCl₃：MgCl₂：AlF₃The molar ratio is (4-3 a-cb): (a-x/3): b: x/3 method prepares LiCl and AlCl₃、MgCl₂And AlF₃。

In examples 41 to 46, as a raw material powder, LiCl: AlCl₃：CaCl₂：AlF₃The molar ratio is (4-3 a-cb): (a-x/3): b: x/3 method prepares LiCl and AlCl₃、CaCl₂And AlF₃。

In examples 47 to 50, as a raw material powder, LiCl: AlCl₃：ZrCl₄：AlF₃The molar ratio is (4-3 a-cb): (a-x/3): b: x/3 method prepares LiCl and AlCl₃、ZrCl₄And AlF₃。

Except for the above, electrolyte materials of examples 33 to 50 were obtained in the same manner as in example 1.

The values of a, b, c, x, and y for the electrolyte materials of examples 33 to 50 are shown in Table 2.

The ion conductivity of the electrolyte materials of examples 33 to 50 was measured in the same manner as in example 1. The measurement results are shown in table 2.

Comparative examples 1 to 3

In comparative example 1, as a raw material powder, LiCl: AlCl₃The molar ratio is 1: 1 LiCl and AlCl were prepared₃。

In comparative example 2, as a raw material powder, LiBr: AlBr₃The molar ratio is 1: mode 1 LiBr and AlBr₃。

In comparative example 3, as a raw material powder, LiF: AlF₃The molar ratio is 1: 1 manner LiF and AlF were prepared₃。

Except for the above, electrolyte materials of comparative examples 1 to 3 were obtained in the same manner as in example 1.

The values of a, b, x, and y for the electrolyte materials of comparative examples 1 to 3 are shown in table 3.

The ion conductivity of the electrolyte materials of comparative examples 1 to 3 was measured in the same manner as in example 1. The measurement results are shown in table 3.

Batteries of comparative examples 1 to 3 were obtained in the same manner as in example 1, using the electrolyte materials of comparative examples 1 to 3. The battery of comparative examples 1 to 3 was used to perform a charge and discharge test in the same manner as in example 1. As a result, the batteries of comparative examples 1 to 3 had initial discharge capacities of 1. mu. Ah or less. The batteries of comparative examples 1 to 3 were neither charged nor discharged.

TABLE 1

TABLE 2

TABLE 3

(examination)

As is clear from tables 1 and 2, the electrolyte materials of examples 1 to 50 had a thickness of 1X 10 at around room temperature^-5High ion conductivity of S/cm or more. On the other hand, as is clear from Table 3, the electrolyte materials of comparative examples 1 to 3 had a composition of less than 1X 10 at around room temperature^-5Ion conductivity of S/cm.

In general, when a part of chlorine or bromine is replaced with fluorine in an electrolyte material, the electrochemical stability is improved, but the ionic conductivity is lowered. This is because fluorine has a very large electronegativity, and therefore fluorine tends to strongly pull a cation, and tends to inhibit lithium ion conduction. However, in the electrolyte material of the present disclosure, the ion conductivity is improved by introducing fluorine.

As is clear from tables 1 and 2, in the formula (1), when x is 0.4. ltoreq. x.ltoreq.2.0, the electrolyte material has high ion conductivity. As is clear from comparison of examples 2 to 12 with example 1, the ion conductivity is further improved when x is 0.8. ltoreq. x.ltoreq.1.8.

As is apparent from table 2, even when M is at least 1 selected from Mg, Ca, and Zr (i.e., 0< b <2 is satisfied in formula (1)), the electrolyte material has high ion conductivity.

From examples 47 to 50, it is understood that when M is Zr, the electrolyte material has a 1X 10^-4High ion conductivity of S/cm or more.

As is clear from tables 1 and 2, in the formula (1), when a.ltoreq.1.0. ltoreq.1.25 is satisfied, the electrolyte material has high ion conductivity.

The batteries of examples 1-32 were all charged and discharged at room temperature. On the other hand, the batteries of comparative examples 1 to 3 were not charged and also were not discharged. Further, the electrolyte materials of examples 1 to 32 did not contain sulfur, and therefore, hydrogen sulfide was not generated.

In summary, the electrolyte material of the present disclosure is a material that is free from hydrogen sulfide generation and has high lithium ion conductivity. The electrolyte material of the present disclosure is suitable for providing a battery capable of being charged and discharged well.

Industrial applicability of the invention

The electrolyte material of the present disclosure is used in, for example, an all-solid lithium ion secondary battery.

Description of the reference numerals

100 electrolytic plasmid

101 powder of electrolyte material

201 positive electrode

202 electrolyte layer

203 negative electrode

204 positive electrode active material particle

205 negative electrode active material particle

300 pressure forming die

301 frame mould

302 lower punch

303 upper punch

1000 cell