Solid electrolyte material and battery using the same

Abstract

A solid electrolyte material according to the present disclosure comprises Li, Yb, M, and X. M is at least one element selected from the group consisting of Mg, Ca, Sr, Ba, Zn, Y, Tb, Gd, Sm, In, Zr, and Hf. X is at least one element selected from the group consisting of F, Cl, Br, and I. A battery 1000 according to the present disclosure comprises a positive electrode 201, a negative electrode 203, and an electrolyte layer 202 provided between the positive electrode 201 and the negative electrode 203. At least one member selected from the group consisting of the positive electrode 201, the negative electrode 203, and the electrolyte layer 202 contains the solid electrolyte material.

Description

[Technical Field]

[0001] The present disclosure relates to a solid electrolyte material and a battery using the same. [Background technology]

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

[0003] Non-Patent Documents 1 and 2 disclose solid electrolyte materials represented by the composition formulae Li3YbCl6 and Li3YbBr6, respectively. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-129312 [Non-Patent Document 1] Z. anorg. allg. Chem., 623,1067-1073(1997) [Non-patent document 2] Z. anorg. allg. Chem., 623,1352-1356(1997) Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present disclosure is to provide a new, highly useful solid electrolyte material. [Means for solving the problem]

[0006] The solid electrolyte material of the present disclosure comprises Li, Yb, M, and X, M is at least one selected from the group consisting of Mg, Ca, Sr, Ba, Zn, Y, Tb, Gd, Sm, In, Zr, and Hf; X is at least one selected from the group consisting of F, Cl, Br, and I. [Effects of the Invention]

[0007] The present disclosure provides a new, highly useful solid electrolyte material. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 shows a cross-sectional view of a battery 1000 according to a second embodiment. [Figure 2] FIG. 2 shows a schematic diagram of a pressing die 300 used to evaluate the ionic conductivity of a solid electrolyte material. [Figure 3] FIG. 3 is a graph showing a Cole-Cole plot obtained by alternating current (AC) impedance measurement of the solid electrolyte material according to Example 1. [Figure 4] FIG. 4 is a graph showing X-ray diffraction patterns of the solid electrolyte materials according to Examples 1, 3 to 14, and 16 to 24, and Comparative Example 2. [Figure 5] FIG. 5 is a graph showing the X-ray diffraction patterns of the solid electrolyte materials according to Examples 2, 3, and 15 and Comparative Example 1. [Figure 6] FIG. 6 is a graph showing the X-ray diffraction patterns of the solid electrolyte materials according to Examples 8 to 17. [Figure 7] FIG. 7 is a graph showing the initial discharge characteristics of the battery according to Example 1. [Figure 8] FIG. 8 is a graph showing a Cole-Cole plot obtained by alternating current (AC) impedance measurement of the solid electrolyte material according to Example B1. [Figure 9] FIG. 9 is a graph showing the X-ray diffraction patterns of the solid electrolyte materials according to Examples B1 to B5, B8 to B10, B12 to B22, and B24 to B33, and Comparative Examples B1 and B2. [Figure 10] FIG. 10 is a graph showing the X-ray diffraction patterns of the solid electrolyte materials according to Examples B6, B7, B9 to B11, B19, B20, and B23, and Comparative Examples B1 and B2. [Figure 11]FIG. 11 is a graph showing the initial discharge characteristics of the battery according to Example B1. [Figure 12] FIG. 12 is a graph showing a Cole-Cole plot obtained by alternating current (AC) impedance measurement of the solid electrolyte material according to Example C1. [Figure 13] FIG. 13 is a graph showing the X-ray diffraction patterns of the solid electrolyte materials according to Examples C1 to C4 and C11 to C13. [Figure 14] FIG. 14 is a graph showing the X-ray diffraction patterns of the solid electrolyte materials according to Examples C5 to C10, C14, and C15. [Figure 15] FIG. 15 is a graph showing the initial discharge characteristics of the battery according to Example C1. [Figure 16] FIG. 16 is a graph showing a Cole-Cole plot obtained by alternating current (AC) impedance measurement of the solid electrolyte material according to Example D1. [Figure 17] FIG. 17 is a graph showing X-ray diffraction patterns of solid electrolyte materials according to Examples D1, D2, D4, D5, D7 to D19, D22 to D24, and D26, and Comparative Examples D1 and D2. [Figure 18] FIG. 18 is a graph showing the X-ray diffraction patterns of the solid electrolyte materials according to Examples D3, D6, D20 to D22, and D25 to D27, and Comparative Examples D1 and D2. [Figure 19] FIG. 19 is a graph showing the initial discharge characteristics of the battery according to Example D1. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The present disclosure is not limited to the following embodiments.

[0010] (First embodiment) The solid electrolyte material according to the first embodiment is composed of Li, Yb, M, and X. M is at least one selected from the group consisting of Mg, Ca, Sr, Ba, Zn, Y, Tb, Gd, Sm, In, Zr, and Hf. X is at least one selected from the group consisting of F, Cl, Br, and I.

[0011] The solid electrolyte material according to the first embodiment is a novel, highly useful solid electrolyte material. The solid electrolyte material according to the first embodiment can have, for example, a practical lithium ion conductivity, for example, a high lithium ion conductivity. Here, the high lithium ion conductivity is, for example, 5.0 × 10 at around room temperature (for example, 25°C). -5 That is, the solid electrolyte material according to the first embodiment has a specific resistance of, for example, 5.0×10 -5 It may have an ionic conductivity of 5 S / cm or more.

[0012] The solid electrolyte material according to the first embodiment can be used to obtain a battery with excellent charge / discharge characteristics. An example of such a battery is an all-solid-state battery. The all-solid-state battery may be a primary battery or a secondary battery.

[0013] The solid electrolyte material according to the first embodiment is substantially free of sulfur. The fact that the solid electrolyte material according to the first embodiment is substantially free of sulfur means that the solid electrolyte material does not contain sulfur as a constituent element, except for sulfur inevitably mixed in as an impurity. In this case, the amount of sulfur mixed in the solid electrolyte material as an impurity is, for example, 1 mol % or less. The solid electrolyte material according to the first embodiment is sulfur-free. A sulfur-free solid electrolyte material does not generate hydrogen sulfide even when exposed to the atmosphere, and is therefore highly safe. The sulfide solid electrolyte disclosed in Patent Document 1 may generate hydrogen sulfide when exposed to the atmosphere.

[0014] The solid electrolyte material according to the first embodiment may contain elements that are inevitably mixed in. Examples of such elements are hydrogen, oxygen, or nitrogen. Such elements may be present in the raw material powder of the solid electrolyte material or in the atmosphere used for producing or storing the solid electrolyte material. In the solid electrolyte material according to the first embodiment, the amount of such elements that are inevitably mixed in is, for example, 1 mol % or less.

[0015] In order to enhance the ionic conductivity of the solid electrolyte material, in the solid electrolyte material according to the first embodiment, M may be at least one selected from the group consisting of Mg, Ca, Sr, Ba, and Zn. M may be at least one selected from the group consisting of Mg, Ca, Sr, and Zn.

[0016] In order to enhance the ionic conductivity of the solid electrolyte material, X may be at least one selected from the group consisting of Cl, Br, and I in the solid electrolyte material according to the first embodiment.

[0017] The solid electrolyte material according to the first embodiment may be a material represented by the following composition formula (1).

[0018] Li 6-3a-2b Yb a M b Cl 6-x-y Br x I y ···(1) Here are the five formulas: 0.2≦a<1.4, 0 <b<0.9、 0≦x≦6, 0 ≤ y ≤ 3, and 0≦x+y≦6 The material represented by composition formula (1) has high ionic conductivity.

[0019] The upper and lower limits of the range of a in composition formula (1) may be defined by any combination selected from the following numerical values: 0.5, 0.6, 0.7, 0.75, 0.8, 0.85, 0.9, 1, and 1.1.

[0020] In order to increase the ionic conductivity of the solid electrolyte material, in the composition formula (1), 0.5 ≦ a ≦ 1.1 may be satisfied.

[0021] The upper and lower limit values of the range of b in the composition formula (1) may be defined by any combination selected from the numerical values of more than 0 (that is, 0 < b), 0.05, 0.1, 0.15, 0.2, 0.3, 0.4, 0.5, and 0.6.

[0022] In order to increase the ionic conductivity of the solid electrolyte material, in the composition formula (1), 0 < b ≦ 0.6 may be satisfied.

[0023] The upper and lower limit values of the range of x in the composition formula (1) may be defined by any combination selected from the numerical values of 0, 2, 3, and 6.

[0024] In order to increase the ionic conductivity of the solid electrolyte material, in the composition formula (1), 0 ≦ y ≦ 2 may be satisfied.

[0025] In order to increase the ionic conductivity of the solid electrolyte material, in the above composition formula (1), the following five mathematical formulas may be satisfied.

[0026] 0.5 ≦ a ≦ 1.1, 0 < b ≦ 0.6, 0 ≦ x ≦ 6, 0 ≦ y ≦ 2, and 0 ≦ x + y ≦ 6 In the composition formula (1), 0 < b ≦ 0.4 and a + b = 1 may be satisfied. According to the above configuration, the solid electrolyte material according to the first embodiment has a higher lithium ion conductivity.

[0027] In order to increase the ionic conductivity of the solid electrolyte material, X may be at least two selected from the group consisting of F, Cl, Br, and I.

[0028] In order to increase the ionic conductivity of the solid electrolyte material, M may contain Zn. M may be Zn.

[0029] The X-ray diffraction pattern of the solid electrolyte material according to the first embodiment can be obtained by X-ray diffraction measurement using the θ-2θ method with Cu-Kα radiation (wavelengths of 1.5405 Å and 1.5444 Å, i.e., wavelengths of 0.15405 nm and 0.15444 nm). The obtained X-ray diffraction pattern may have at least one peak in the diffraction angle 2θ range of 13.0° to 15.0°, and may also have at least two peaks in the diffraction angle 2θ range of 26.0° to 35.0°. A crystalline phase having such peaks is called a first crystalline phase. In a solid electrolyte material containing the first crystalline phase, paths for lithium ion diffusion within the crystal are easily formed. Therefore, when the solid electrolyte material according to the first embodiment contains the first crystalline phase, the solid electrolyte material according to the first embodiment has high ionic conductivity.

[0030] The crystal system of the first crystal phase belongs to the monoclinic system. In this disclosure, "monoclinic" refers to a crystal phase having a crystal structure similar to that of Li3InCl6 disclosed in ICSD (Inorganic Crystal Structure Database) Collection Code 89617 and having an X-ray diffraction pattern specific to this structure. In this disclosure, "having a similar crystal structure" means being classified into the same space group and having a similar atomic arrangement structure, but does not limit the lattice constant. Furthermore, the relative intensity ratio and diffraction angle of the diffraction peaks in the X-ray diffraction pattern of the solid electrolyte material according to the first embodiment may vary from the diffraction pattern of Li3InCl6.

[0031] In the X-ray diffraction pattern of the solid electrolyte material according to the first embodiment obtained by X-ray diffraction measurement using Cu-Kα radiation, at least one peak may be present in a diffraction angle 2θ range of 22.0° to 23.5°, at least two peaks may be present in a diffraction angle 2θ range of 31.0° to 35.0°, and at least one peak may be present in a diffraction angle 2θ range of 40.0° to 42.0°. A crystalline phase having these peaks is called a second crystalline phase. A solid electrolyte material containing the second crystalline phase is likely to form a path for lithium ion diffusion within the crystal. Therefore, when the solid electrolyte material according to the first embodiment contains the second crystalline phase, the solid electrolyte material according to the first embodiment has high ionic conductivity.

[0032] The crystal system of the second crystal phase belongs to the orthorhombic system. In this disclosure, "orthorhombic" refers to a crystal phase having a crystal structure similar to that of Li3YbCl6 disclosed in ICSD Collection Code 50152 and having an X-ray diffraction pattern specific to this structure. The relative intensity ratios and diffraction angles of the diffraction peaks in the X-ray diffraction pattern of the solid electrolyte material according to the first embodiment may vary from the diffraction pattern of Li3YbCl6.

[0033] In the X-ray diffraction pattern of the solid electrolyte material according to the first embodiment obtained by X-ray diffraction measurement using Cu-Kα radiation, at least two peaks may be present in a diffraction angle 2θ range of 21.0° to 24.0°, at least two peaks may be present in a diffraction angle 2θ range of 31.0° to 35.0°, and at least one peak may be present in a diffraction angle 2θ range of 40.0° to 42.0°. A crystalline phase having these peaks is called a third crystalline phase. A solid electrolyte material containing the third crystalline phase is likely to form a path for lithium ion diffusion within the crystal. Therefore, when the solid electrolyte material according to the first embodiment contains the third crystalline phase, the solid electrolyte material according to the first embodiment has high ionic conductivity.

[0034] The crystal system of the third crystal phase belongs to the trigonal system. In this disclosure, "trigonal" refers to a crystal phase having a crystal structure similar to that of Li3ErCl6 disclosed in ICSD Collection Code 50151 and having an X-ray diffraction pattern specific to this structure. The relative intensity ratios and diffraction angles of the diffraction peaks in the X-ray diffraction pattern of the solid electrolyte material according to the first embodiment may vary from the diffraction pattern of Li3ErCl6.

[0035] The solid electrolyte material according to the first embodiment may further contain a fourth crystalline phase different from the first, second, and third crystalline phases. That is, the solid electrolyte material according to the first embodiment may further contain a fourth crystalline phase having a clear peak outside the range of the diffraction angle 2θ described above. The fourth crystalline phase may be, for example, one that is attributed to a spinel structure. The spinel structure may be, for example, a structure similar to Li2ZnCl4 disclosed in ICSD Collection Code 202743.

[0036] In order to increase the ionic conductivity of the solid electrolyte material, in the solid electrolyte material according to the first embodiment, M may be at least one selected from the group consisting of Y, Tb, Gd, Sm, and In. In order to further increase the ionic conductivity of the solid electrolyte material, in the solid electrolyte material according to the first embodiment, M may be at least one selected from the group consisting of Y, Tb, Gd, and Sm.

[0037] In order to enhance the ionic conductivity of the solid electrolyte material, in the solid electrolyte material according to the first embodiment, X may be at least one selected from the group consisting of Cl, Br, and I.

[0038] The solid electrolyte material according to the first embodiment may be a material represented by the following composition formula (2).

[0039] Li 6-3a (Yb 1-b M b ) a Cl 6-x-y Br xI y ···(2) Here, the following five mathematical formulas: 0.5 ≤ a ≤ 1.5, 0 < b < 1, 0 ≤ x ≤ 6, 0 ≤ y ≤ 3, and 0 ≤ x + y ≤ 6 are satisfied. The material represented by the compositional formula (2) has high ionic conductivity.

[0040] In order to increase the ionic conductivity of the solid electrolyte material, in the above compositional formula (2), the following five mathematical formulas may be satisfied.

[0041] 1 ≤ a ≤ 1.1, 0 < b < 1, 0 ≤ x ≤ 6, 0 ≤ y ≤ 2, and 0 ≤ x + y ≤ 6 In order to increase the ionic conductivity of the solid electrolyte material, in the compositional formula (2), 1 ≤ a ≤ 1.1 may be satisfied. In order to further increase the ionic conductivity of the solid electrolyte material, in the compositional formula (2), a = 1 may be satisfied.

[0042] The upper and lower limit values of the range of b in the compositional formula (2) may be defined by any combination selected from numerical values greater than 0 (i.e., 0 < b), 0.1, 0.2, 0.3, 0.4, 0.5, 0.7, 0.9, and less than 1 (i.e., b < 1).

[0043] The upper and lower limit values of the range of x in the compositional formula (2) may be defined by any combination selected from the numerical values 0, 1, 1.5, 2, 3, and 6.

[0044] In order to increase the ionic conductivity of the solid electrolyte material, in the compositional formula (2), 0 < x < 6 may be satisfied.

[0045] The upper and lower limit values of the range of y in the compositional formula (2) may be defined by any combination selected from the numerical values 0, 0.5, 1, and 2.

[0046] In order to increase the ionic conductivity of the solid electrolyte material, the formula (1) may satisfy 0≦y≦2. In order to further increase the ionic conductivity of the solid electrolyte material, the formula (1) may satisfy y=1.

[0047] The X-ray diffraction pattern of the solid electrolyte material according to the first embodiment can be obtained by X-ray diffraction measurement using the θ-2θ method with Cu-Kα radiation (wavelengths of 1.5405 Å and 1.5444 Å, i.e., wavelengths of 0.15405 nm and 0.15444 nm). The obtained X-ray diffraction pattern may have at least one peak in the diffraction angle 2θ range of 13.0° to 15.0°, and may also have at least two peaks in the diffraction angle 2θ range of 26.0° to 35.0°. A crystalline phase having such peaks is called a fifth crystalline phase. In a solid electrolyte material containing the fifth crystalline phase, paths for lithium ion diffusion within the crystal are easily formed. Therefore, when the solid electrolyte material according to the first embodiment contains the fifth crystalline phase, the solid electrolyte material according to the first embodiment has high ionic conductivity.

[0048] The crystal system of the fifth crystal phase belongs to the monoclinic system.

[0049] In the X-ray diffraction pattern of the solid electrolyte material according to the first embodiment obtained by X-ray diffraction measurement using Cu-Kα radiation, at least two peaks may be present in a diffraction angle 2θ range of 20.5° to 24.0°, at least two peaks may be present in a diffraction angle 2θ range of 30.0° to 35.0°, and at least one peak may be present in a diffraction angle 2θ range of 39.0° to 42.0°. The crystalline phase having these peaks is called a sixth crystalline phase. In a solid electrolyte material containing the sixth crystalline phase, paths for lithium ion diffusion within the crystal are easily formed. Therefore, when the solid electrolyte material according to the first embodiment contains the sixth crystalline phase, the solid electrolyte material according to the first embodiment has high ionic conductivity.

[0050] The crystal system of the sixth crystal phase belongs to the trigonal system.

[0051] The solid electrolyte material according to the first embodiment may further contain a seventh crystal phase different from the fifth and sixth crystal phases. That is, the solid electrolyte material according to the first embodiment may further contain a seventh crystal phase having a clear peak outside the above-mentioned range of diffraction angle 2θ. The seventh crystal phase may be, for example, one that is attributed to a crystal structure similar to Li3YbCl6 disclosed in ICSD Collection Code 50152 or a crystal structure similar to LiGdCl4 disclosed in ICSD Collection Code 38326.

[0052] In order to enhance the ionic conductivity of the solid electrolyte material, in the solid electrolyte material according to the first embodiment, M may be at least one selected from the group consisting of Zr and Hf.

[0053] In order to enhance the ionic conductivity of the solid electrolyte material, in the solid electrolyte material according to the first embodiment, X may be at least one selected from the group consisting of Cl, Br, and I.

[0054] The solid electrolyte material according to the first embodiment may be a material represented by the following composition formula (3).

[0055] Li 6-3a-4b Yb a M b Cl 6-x-y Br x I y ···(3) Here are the six formulas: 0 <a<1.5、 0 <b<1.5、 0<3a+4b<6 0≦x≦6, 0 ≤ y ≤ 3, and 0≦x+y≦6 The material represented by composition formula (3) has high ionic conductivity.

[0056] The upper and lower limit values of the range of a in the compositional formula (3) may be defined by any combination selected from values greater than 0 (i.e., 0 < a), 0.1, 0.3, 0.4, 0.5, 0.55, 0.6, 0.7, 0.8, 0.9, and less than 1 (i.e., a < 1).

[0057] In order to increase the ionic conductivity of the solid electrolyte material, in the compositional formula (3), 0 < a < 1 may be satisfied.

[0058] The upper and lower limit values of the range of b in the compositional formula (3) may be defined by any combination selected from values greater than 0 (i.e., 0 < b), 0.1, 0.3, 0.35, 0.4, 0.45, 0.5, 0.6, 0.9, and less than 1 (i.e., b < 1).

[0059] In order to increase the ionic conductivity of the solid electrolyte material, in the compositional formula (3), 0 < b < 1 may be satisfied.

[0060] The upper and lower limit values of the range of x in the compositional formula (3) may be defined by any combination selected from the values 0, 1, 2, 3, 4, and 6.

[0061] In order to increase the ionic conductivity of the solid electrolyte material, in the compositional formula (3), 0 ≤ x ≤ 3 may be satisfied.

[0062] The upper and lower limit values of the range of y in the compositional formula (3) may be defined by any combination selected from the values 0, 1, and 2.

[0063] In order to increase the ionic conductivity of the solid electrolyte material, in the compositional formula (3), 0 ≤ y ≤ 2 may be satisfied. In order to increase the ionic conductivity of the solid electrolyte material, in the compositional formula (3), y > 0 may be satisfied.

[0064] In order to increase the ionic conductivity of the solid electrolyte material, in the compositional formula (3), a ≤ 0.7 and b ≥ 0.3 may be satisfied.

[0065] In order to enhance the ionic conductivity of the solid electrolyte material, the formula (3) may satisfy a=0.5 and b=0.5.

[0066] In order to enhance the ionic conductivity of the solid electrolyte material, the above composition formula (3) may satisfy the following six formulas:

[0067] 0 <a<1.5、 0 <b<1.5、 0<3a+4b<6 0≦x≦6, 0 ≤ y ≤ 3, and 0≦x+y≦6 The X-ray diffraction pattern of the solid electrolyte material according to the first embodiment can be obtained by X-ray diffraction measurement using the θ-2θ method with Cu-Kα radiation (wavelengths of 1.5405 Å and 1.5444 Å, i.e., wavelengths of 0.15405 nm and 0.15444 nm). The obtained X-ray diffraction pattern may have at least one peak in each of the diffraction angle 2θ ranges of 14.0° to 18.0°, 29.0° to 35.0°, and 48.0° to 52.0°. A crystalline phase having such a peak is called the eighth crystalline phase. A solid electrolyte material containing the eighth crystalline phase is likely to have a path for lithium ion diffusion within the crystal. Therefore, when the solid electrolyte material according to the first embodiment contains the first crystalline phase, the solid electrolyte material according to the first embodiment has high ionic conductivity.

[0068] In the X-ray diffraction pattern of the solid electrolyte material according to the first embodiment obtained by X-ray diffraction measurement using Cu-Kα radiation, at least two peaks may be present in the diffraction angle 2θ range of 26.0° or more and 35.0° or less, and at least one peak may be present in the diffraction angle 2θ range of 13.0° or more and 17.0° or less. The crystalline phase having these peaks is called the ninth crystalline phase. In a solid electrolyte material containing the second crystalline phase, paths for lithium ion diffusion within the crystal are easily formed. Therefore, when the solid electrolyte material according to the first embodiment contains the ninth crystalline phase, the solid electrolyte material according to the first embodiment has high ionic conductivity.

[0069] The solid electrolyte material according to the first embodiment may further contain a tenth crystal phase different from the eighth and ninth crystal phases. That is, the solid electrolyte material according to the first embodiment may further contain a tenth crystal phase having a clear peak outside the above-mentioned range of diffraction angle 2θ.

[0070] In order to enhance the ionic conductivity of the solid electrolyte material, in the solid electrolyte material according to the first embodiment, M may consist of M1 and M2, where M1 is at least one selected from the group consisting of Y, Tb, Gd, Sm, and In, and M2 may be at least one selected from the group consisting of Mg, Ca, Sr, Ba, and Zn.

[0071] In order to enhance the ionic conductivity of the solid electrolyte material, in the solid electrolyte material according to the first embodiment, M1 may be one selected from the group consisting of Y, Tb, Gd, and Sm.

[0072] In order to enhance the ionic conductivity of the solid electrolyte material, in the solid electrolyte material according to the first embodiment, M2 may be at least one selected from the group consisting of Mg, Ca, Sr, and Zn. M2 may be at least one selected from the group consisting of Mg, Sr, and Zn.

[0073] In order to increase the ionic conductivity of the solid electrolyte material, in the solid electrolyte material according to the first embodiment, X may be at least one selected from the group consisting of Cl and Br.

[0074] The solid electrolyte material according to the first embodiment may be a material represented by the following compositional formula (4). Li 6-3a-3b-2c Yb a M1 b M2 c Cl 6-x Br x ···(4) Here, the following four mathematical formulas: 0.3 ≦ a ≦ 1.2, 0 < b ≦ 0.5, 0 < c ≦ 0.4, and, 0 ≦ x ≦ 6, are satisfied. The material represented by the compositional formula (4) has high ionic conductivity.

[0075] In order to increase the ionic conductivity of the solid electrolyte material, in the above compositional formula (4), the following four mathematical formulas may be satisfied.

[0076] 0.65 ≦ a < 1, 0 < b ≦ 0.3, 0 < c ≦ 0.2, and, 0 ≦ x ≦ 6 The upper and lower limit values of the range of a in the compositional formula (4) may be defined by any combination selected from the numerical values of 0.65, 0.7, 0.8, and less than 1 (i.e., a < 1).

[0077] In order to increase the ionic conductivity of the solid electrolyte material, in the compositional formula (4), 0.65 ≦ a < 1 may be satisfied.

[0078] The upper and lower limit values of the range of b in the compositional formula (4) may be defined by any combination selected from the numerical values greater than 0 (i.e., 0 < b), 0.1, 0.2, 0.25, and 0.3.

[0079] In order to increase the ionic conductivity of the solid electrolyte material, in Composition Formula (4), 0 < b ≤ 0.3 may be satisfied.

[0080] The upper and lower limit values of the range of c in Composition Formula (4) may be defined by any combination selected from the numerical values of more than 0 (i.e., 0 < c), 0.05, 0.1, 0.15, and 0.2.

[0081] In order to increase the ionic conductivity of the solid electrolyte material, in Composition Formula (4), 0 < c ≤ 0.2 may be satisfied. In order to further increase the ionic conductivity of the solid electrolyte material, in Composition Formula (4), 0 < c ≤ 0.1 may be satisfied.

[0082] The upper and lower limit values of the range of x in Composition Formula (4) may be defined by any combination selected from the numerical values of 0, 1, 3, and 6.

[0083] In order to increase the ionic conductivity of the solid electrolyte material, in Composition Formula (4), 0 ≤ x ≤ 3 may be satisfied.

[0084] The X-ray diffraction pattern of the solid electrolyte material according to the first embodiment can be obtained by X-ray diffraction measurement using the θ-2θ method with Cu-Kα rays (wavelengths 1.5405 Å and 1.5444 Å, i.e., wavelengths 0.15405 nm and 0.15444 nm). In the obtained X-ray diffraction pattern, at least one peak may exist in the range of diffraction angle 2θ of 13.0° or more and 15.0° or less, and at least two peaks may exist in the range of diffraction angle 2θ of 26.0° or more and 35.0° or less. The crystal phase having such peaks is called the 11th crystal phase. In the solid electrolyte material containing the 11th crystal phase, a path for lithium ions to diffuse in the crystal is likely to be formed. Therefore, when the solid electrolyte material according to the first embodiment contains the 11th crystal phase, the solid electrolyte material according to the first embodiment has high ionic conductivity.

[0085] The crystal system of the 11th crystal phase belongs to the monoclinic system.

[0086] In an X-ray diffraction pattern of the solid electrolyte material according to the first embodiment obtained by X-ray diffraction measurement using Cu-Kα radiation, at least two peaks may be present in a diffraction angle 2θ range of 20.5° to 24.0°, at least two peaks may be present in a diffraction angle 2θ range of 30.0° to 35.0°, and at least one peak may be present in a diffraction angle 2θ range of 39.0° to 42.0°. A crystalline phase having these peaks is called a 12th crystalline phase. A solid electrolyte material containing the 12th crystalline phase is likely to form a path for lithium ion diffusion within the crystal. Therefore, when the solid electrolyte material according to the first embodiment contains the 12th crystalline phase, the solid electrolyte material according to the first embodiment has high ionic conductivity.

[0087] The crystal system of the 12th crystal phase belongs to the trigonal system.

[0088] The solid electrolyte material according to the first embodiment may further contain a 13th crystal phase different from the 11th and 12th crystal phases. That is, the solid electrolyte material according to the first embodiment may further contain a 13th crystal phase having a clear peak outside the above-mentioned range of diffraction angle 2θ. The 13th crystal phase may be, for example, a crystal structure similar to that of Li3YbCl6 disclosed in ICSD Collection Code 50152 or a crystal structure similar to that of LiGdCl4 disclosed in ICSD Collection Code 38326.

[0089] The solid electrolyte material according to the first embodiment may be crystalline or amorphous. Furthermore, the solid electrolyte material according to the first embodiment may be a mixture of crystalline and amorphous. Here, crystalline refers to the presence of a peak in the X-ray diffraction pattern. Amorphous refers to the presence of a broad peak (i.e., a halo) in the X-ray diffraction pattern. When amorphous and crystalline are mixed, a peak and a halo are present in the X-ray diffraction pattern.

[0090] The shape of the solid electrolyte material according to the first embodiment is not limited. Examples of the shape include a needle shape, a sphere shape, or an oval sphere shape. The solid electrolyte material according to the first embodiment may be in the form of particles. The solid electrolyte material according to the first embodiment may be formed into the shape of a pellet or a plate.

[0091] When the solid electrolyte material according to the first embodiment has a particulate (e.g., spherical) shape, the solid electrolyte material may have a median diameter of 0.1 μm or more and 100 μm or less. The median diameter refers to the particle size when the cumulative volume in the volume-based particle size distribution is equal to 50%. The volume-based particle size distribution is measured, for example, by a laser diffraction measurement device or an image analysis device.

[0092] The solid electrolyte material according to the first embodiment may have a median diameter of 0.5 μm or more and 10 μm or less. This allows the solid electrolyte material according to the first embodiment to have higher ionic conductivity. Furthermore, when the solid electrolyte material according to the first embodiment is mixed with other materials such as active materials, the solid electrolyte material according to the first embodiment and the other materials are well dispersed.

[0093] <Method of manufacturing solid electrolyte material> The solid electrolyte material according to the first embodiment is produced, for example, by the following method.

[0094] Two or more kinds of halide raw material powders are mixed together to obtain a desired composition.

[0095] As an example, if the desired composition is Li 3.15 Yb 0.85 Mg 0.15 In the case of Cl6, LiCl raw material powder, YbCl3 raw material powder, and MgCl2 raw material powder (i.e., raw material powders of three halides) are mixed to a molar ratio of approximately 3.15:0.85:0.15. The raw material powders may be mixed in a pre-adjusted molar ratio to offset compositional changes that may occur during the synthesis process.

[0096] The mixture of raw material powders is fired in an inert gas atmosphere to react with each other and obtain a reactant. Examples of the inert gas include helium, nitrogen, and argon. The firing process may be performed in a vacuum. In the firing process, the powder of the mixed material may be placed in a container (e.g., a crucible or a sealed tube) and fired in a heating furnace.

[0097] Alternatively, the raw material powders may be reacted with each other mechanochemically (i.e., by using a mechanochemical milling method) in a mixing device such as a planetary ball mill to obtain a reactant, which may then be calcined in an inert gas atmosphere or in vacuum.

[0098] By these methods, the solid electrolyte material according to the first embodiment can be obtained.

[0099] (Second embodiment) A second embodiment of the present disclosure will be described below. The matters described in the first embodiment may be omitted.

[0100] In the second embodiment, a battery using the solid electrolyte material according to the first embodiment will be described.

[0101] The battery according to the second embodiment includes 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 one selected from the group consisting of the positive electrode, the electrolyte layer, and the negative electrode contains the solid electrolyte material according to the first embodiment.

[0102] The battery according to the second embodiment has excellent charge / discharge characteristics because it contains the solid electrolyte material according to the first embodiment. The battery may be an all-solid-state battery.

[0103] FIG. 1 shows a cross-sectional view of a battery 1000 according to a second embodiment.

[0104] The battery 1000 according to the second embodiment includes a positive electrode 201, an electrolyte layer 202, and a negative electrode 203. The electrolyte layer 202 is provided between the positive electrode 201 and the negative electrode 203.

[0105] The positive electrode 201 contains positive electrode active material particles 204 and solid electrolyte particles 100 .

[0106] The electrolyte layer 202 contains an electrolyte material, such as a solid electrolyte material.

[0107] The negative electrode 203 contains negative electrode active material particles 205 and solid electrolyte particles 100 .

[0108] The solid electrolyte particles 100 are particles containing the solid electrolyte material according to the first embodiment. The solid electrolyte particles 100 may be particles made of the solid electrolyte material according to the first embodiment, or particles containing the solid electrolyte material according to the first embodiment as a main component. Here, particles containing the solid electrolyte material according to the first embodiment as a main component refer to particles in which the component contained most abundantly in terms of molar ratio is the solid electrolyte material according to the first embodiment.

[0109] The solid electrolyte particles 100 may have a median diameter of 0.1 μm or more and 100 μm or less, or may have a median diameter of 0.5 μm or more and 10 μm or less, in which case the solid electrolyte particles 100 have higher ionic conductivity.

[0110] The positive electrode 201 contains a material capable of absorbing and releasing metal ions (for example, lithium ions). The material is, for example, a positive electrode active material (for example, positive electrode active material particles 204).

[0111] Examples of the positive electrode active material include a lithium-containing transition metal oxide, a transition metal fluoride, a polyanionic material, a fluorinated polyanionic material, a transition metal sulfide, a transition metal oxyfluoride, a transition metal oxysulfide, or a transition metal oxynitride. Examples of the lithium-containing transition metal oxide include Li(Ni,Co,Al)O2 and LiCoO2.

[0112] In the present disclosure, the notation "(A, B, C)" in a chemical formula means "at least one selected from the group consisting of A, B, and C." For example, "(Ni, Co, Al)" is synonymous with "at least one selected from the group consisting of Ni, Co, and Al."

[0113] The positive electrode active material particles 204 may have a median diameter of 0.1 μm or more and 100 μm or less. When the positive electrode active material particles 204 have a median diameter of 0.1 μm or more, the positive electrode active material particles 204 and the solid electrolyte particles 100 are well dispersed in the positive electrode 201. This improves the charge / discharge characteristics of the battery. When the positive electrode active material particles 204 have a median diameter of 100 μm or less, the lithium diffusion rate within the positive electrode active material particles 204 improves. This allows the battery to operate at high power.

[0114] The positive electrode active material particles 204 may have a larger median diameter than the solid electrolyte particles 100. This improves the dispersion state of the positive electrode active material particles 204 and the solid electrolyte particles 100 in the positive electrode 201.

[0115] In order to increase the energy density and output of the battery, in the positive electrode 201, the ratio of the volume of the positive electrode active material particles 204 to the sum of the volume of the positive electrode active material particles 204 and the volume of the solid electrolyte particles 100 may be 0.30 or more and 0.95 or less.

[0116] To increase the energy density and power output of the battery, the positive electrode 201 may have a thickness of 10 μm or more and 500 μm or less.

[0117] The electrolyte layer 202 contains an electrolyte material. The electrolyte material is, for example, the solid electrolyte material according to the first embodiment. The electrolyte layer 202 may be a solid electrolyte layer.

[0118] The electrolyte layer 202 may be made of only the solid electrolyte material according to the first embodiment, or may be made of only a solid electrolyte material different from the solid electrolyte material according to the first embodiment.

[0119] Examples of solid electrolyte materials different from the solid electrolyte material according to the first embodiment include Li2MgX'4, Li2FeX'4, Li(Al,Ga,In)X'4, Li3(Al,Ga,In)X'6, or LiI, where X' is at least one selected from the group consisting of F, Cl, Br, and I. Thus, the solid electrolyte material different from the solid electrolyte material according to the first embodiment may be a solid electrolyte containing a halogen element, i.e., a halide solid electrolyte.

[0120] Hereinafter, the solid electrolyte material according to the first embodiment will be referred to as a first solid electrolyte material, and a solid electrolyte material different from the solid electrolyte material according to the first embodiment will be referred to as a second solid electrolyte material.

[0121] The electrolyte layer 202 may contain not only the first solid electrolyte material but also the second solid electrolyte material. The first solid electrolyte material and the second solid electrolyte material may be uniformly dispersed in the electrolyte layer 202. A layer made of the first solid electrolyte material and a layer made of the second solid electrolyte material may be stacked along the stacking direction of the battery 1000.

[0122] The electrolyte layer 202 may have a thickness of 1 μm or more and 1000 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 short-circuit. When the electrolyte layer 202 has a thickness of 1000 μm or less, the battery can operate at high power.

[0123] The negative electrode 203 contains a material capable of absorbing and releasing metal ions such as lithium ions. The material is, for example, a negative electrode active material (for example, negative electrode active material particles 205).

[0124] Examples of the negative electrode active material include a metal material, a carbon material, an oxide, a nitride, a tin compound, or a silicon compound. The metal material may be a simple metal or an alloy. An example of the metal material is lithium metal or a lithium alloy. Examples of the carbon material are natural graphite, coke, partially graphitized carbon, carbon fiber, spherical carbon, artificial graphite, or amorphous carbon. From the viewpoint of capacity density, suitable examples of the negative electrode active material are silicon (i.e., Si), tin (i.e., Sn), a silicon compound, or a tin compound.

[0125] The negative electrode active material particles 205 may have a median diameter of 0.1 μm or more and 100 μm or less. When the negative electrode active material particles 205 have a median diameter of 0.1 μm or more, the negative electrode active material particles 205 and the solid electrolyte particles 100 are 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 diameter of 100 μm or less, the lithium diffusion rate within the negative electrode active material particles 205 improves. This allows the battery to operate at high power.

[0126] The negative electrode active material particles 205 may have a larger median diameter than the solid electrolyte particles 100. This improves the dispersion state of the negative electrode active material particles 205 and the solid electrolyte particles 100 in the negative electrode 203.

[0127] In order to increase the energy density and output of the battery, in the negative electrode 203, the ratio of the volume of the negative electrode active material particles 205 to the sum of the volume of the negative electrode active material particles 205 and the volume of the solid electrolyte particles 100 may be 0.30 or more and 0.95 or less.

[0128] To increase the energy density and power output of the battery, the negative electrode 203 may have a thickness of 10 μm or more and 500 μm or less.

[0129] At least one selected from the group consisting of the positive electrode 201, the electrolyte layer 202, and the negative electrode 203 may contain a second solid electrolyte material for the purpose of increasing ionic conductivity, chemical stability, and electrochemical stability.

[0130] As mentioned above, the second solid electrolyte material may be a halide solid electrolyte.

[0131] Examples of halide solid electrolytes are Li2MgX'4, Li2FeX'4, Li(Al,Ga,In)X'4, Li3(Al,Ga,In)X'6, or LiI, where X' is at least one selected from the group consisting of F, Cl, Br, and I.

[0132] Other examples of halide solid electrolytes are Li p Me q Y r Z6, where p + m'q + 3r = 6 and r > 0. Me is at least one element selected from the group consisting of metal elements and metalloid elements other than Li and Y. The value of m' represents the valence of Me. Z is at least one element selected from the group consisting of F, Cl, Br, and I. "Metalloid elements" are B, Si, Ge, As, Sb, and Te. "Metal elements" are all elements in Groups 1 to 12 of the Periodic Table (excluding hydrogen) and all elements in Groups 13 to 16 of the Periodic Table (excluding B, Si, Ge, As, Sb, Te, C, N, P, O, S, and Se). To increase the ionic conductivity of the halide solid electrolyte, Me may be at least one element selected from the group consisting of Mg, Ca, Sr, Ba, Zn, Sc, Al, Ga, Bi, Zr, Hf, Ti, Sn, Ta, and Nb.

[0133] The second solid electrolyte material may be a sulfide solid electrolyte.

[0134] Examples of sulfide solid electrolytes are Li2S-P2S5, Li2S-SiS2, Li2S-B2S3, Li2S-GeS2, Li 3.25 Ge 0.25 P 0.75 S4, or Li 10 GeP2S 12 is.

[0135] The second solid electrolyte material may be an oxide solid electrolyte.

[0136] Examples of oxide solid electrolytes include: (i) NASICON-type solid electrolytes such as LiTi2(PO4)3 or its elemental substitutes; (ii) Perovskite-type solid electrolytes such as (LaLi)TiO3; (iii) Li 14 ZnGeO 16 LISICON-type solid electrolytes such as Li4SiO4, LiGeO4 or elemental substitutions thereof; (iv) Li7La3Zr2O 12 or a garnet-type solid electrolyte such as an elemental substitution product thereof, or (v) Li3PO4 or its N-substituted derivatives is.

[0137] The second solid electrolyte material may be an organic polymer solid electrolyte.

[0138] An example of the organic polymer solid electrolyte is a compound of a polymer compound and a lithium salt.

[0139] The polymer compound may have an ethylene oxide structure. A polymer compound having an ethylene oxide structure can contain a large amount of lithium salt, and therefore can further increase ionic conductivity.

[0140] Examples of lithium salts include LiPF, LiBF, LiSbF, LiAsF, LiSOCF, LiN(SOCF), LiN(SOCF) , LiN(SOCF)(SOCF), or LiC(SOCF). One lithium salt selected from these may be used alone. Alternatively, a mixture of two or more lithium salts selected from these may be used.

[0141] At least one selected from the group consisting of the positive electrode 201, the electrolyte layer 202, and the negative electrode 203 may contain a non-aqueous electrolyte solution, a gel electrolyte, or an ionic liquid in order to facilitate the exchange of lithium ions and improve the output characteristics of the battery.

[0142] The non-aqueous electrolyte contains a non-aqueous solvent and a lithium salt dissolved in the non-aqueous solvent.

[0143] Examples of non-aqueous solvents include cyclic carbonate ester solvents, chain carbonate ester solvents, cyclic ether solvents, chain ether solvents, cyclic ester solvents, chain ester solvents, and fluorine-containing solvents. Examples of cyclic carbonate ester solvents include ethylene carbonate, propylene carbonate, and butylene carbonate. Examples of chain carbonate ester solvents include dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate. Examples of cyclic ether solvents include tetrahydrofuran, 1,4-dioxane, and 1,3-dioxolane. Examples of chain ether solvents include 1,2-dimethoxyethane and 1,2-diethoxyethane. Examples of cyclic ester solvents include γ-butyrolactone. Examples of chain ester solvents include methyl acetate. Examples of fluorine-containing solvents include fluoroethylene carbonate, methyl fluoropropionate, fluorobenzene, fluoroethyl methyl carbonate, and fluorodimethylene carbonate. One non-aqueous solvent selected from these may be used alone, or a mixture of two or more non-aqueous solvents selected from these may be used.

[0144] Examples of lithium salts are LiPF6, LiBF4, LiSbF6, LiAsF6, LiSO3CF3, LiN(SO2CF3)2, LiN(SO2C2F5)2, LiN(SO2CF3)(SO2C4F9), or LiC(SO2CF3)3. One lithium salt selected from these may be used alone. Alternatively, a mixture of two or more lithium salts selected from these may be used. The concentration of the lithium salt is, for example, 0.5 mol / L or more and 2 mol / L or less.

[0145] The gel electrolyte may be a polymer material impregnated with a non-aqueous electrolyte, such as polyethylene oxide, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, or a polymer having an ethylene oxide bond.

[0146] Examples of cations contained in ionic liquids are: (i) Aliphatic chain quaternary salts such as tetraalkylammonium or tetraalkylphosphonium; (ii) aliphatic cyclic ammoniums such as pyrrolidiniums, morpholiniums, imidazoliniums, tetrahydropyrimidiniums, piperaziniums, or piperidiniums, or (iii) nitrogen-containing heterocyclic aromatic cations such as pyridiniums or imidazoliums is.

[0147] An example of an anion found in ionic liquids is PF6 - , BF4 - , SbF6 - , AsF6 - , SO3CF3 - , N(SO2CF3)2 - , N(SO2C2F5)2 - , N(SO2CF3)(SO2C4F9) - , or C(SO2CF3)3 - is.

[0148] The ionic liquid may contain a lithium salt.

[0149] At least one selected from the group consisting of 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.

[0150] Examples of binders include polyvinylidene fluoride, polytetrafluoroethylene, polyethylene, polypropylene, aramid resin, polyamide, polyimide, polyamideimide, polyacrylonitrile, polyacrylic acid, polymethyl ester of acrylic acid, polyethyl ester of acrylic acid, polyhexyl ester of acrylic acid, polymethacrylic acid, polymethyl ester of methacrylic acid, polyethyl ester of methacrylic acid, polyhexyl ester of methacrylic acid, polyvinyl acetate, polyvinylpyrrolidone, polyether, polyethersulfone, hexafluoropolypropylene, styrene-butadiene rubber, and carboxymethyl cellulose. Copolymers can also be used as binders. Examples of such binders include copolymers of two or more materials selected from the group consisting of tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, perfluoroalkyl vinyl ether, vinylidene fluoride, chlorotrifluoroethylene, ethylene, propylene, pentafluoropropylene, fluoromethyl vinyl ether, acrylic acid, and hexadiene. Mixtures of two or more of the above materials may also be used as binders.

[0151] At least one selected from the positive electrode 201 and the negative electrode 203 may contain a conductive additive for the purpose of increasing electronic conductivity.

[0152] Examples of the conductive additive include: (i) graphites such as natural or synthetic graphite; (ii) carbon blacks such as acetylene black or ketjen black; (iii) conductive fibers such as carbon or metal fibers; (iv) fluorocarbons; (v) Metal powders such as aluminum; (vi) conductive whiskers such as zinc oxide or potassium titanate; (vii) a conductive metal oxide, such as titanium oxide; or (viii) Conductive polymers such as polyaniline, polypyrrole, or polythiophene To reduce costs, the above-mentioned conductive additive (i) or (ii) may be used.

[0153] Examples of the shape of the battery according to the second embodiment include a coin type, a cylindrical type, a square type, a sheet type, a button type, a flat type, and a laminate type.

[0154] The battery according to the second embodiment may be manufactured, for example, by preparing a material for forming a positive electrode, a material for forming an electrolyte layer, and a material for forming a negative electrode, and by using a known method to fabricate a laminate in which the positive electrode, the electrolyte layer, and the negative electrode are arranged in this order. [Example]

[0155] The present disclosure will now be described in more detail with reference to Examples A, B, C and D.

[0156] The solid electrolyte material according to Example A can be represented by the above-mentioned composition formula (1).

[0157] Example A1 (Preparation of solid electrolyte materials) In an argon atmosphere having a dew point of -60°C or less (hereinafter referred to as "dry argon atmosphere"), raw material powders of LiCl, YbCl3, and MgCl2 were prepared in a molar ratio of LiCl:YbCl3:MgCl2 = 3.15:0.85:0.15. These raw material powders were ground and mixed in an agate mortar. The resulting mixed powder was placed in an alumina crucible and fired at 600°C for 1 hour in a dry argon atmosphere. The resulting fired product was ground in the agate mortar. In this way, a powder of the solid electrolyte material according to Example A1 was obtained. The solid electrolyte material according to Example A1 contained Li 3.15 Yb 0.85 Mg 0.15 It had a composition represented by Cl6.

[0158] (Evaluation of ionic conductivity) FIG. 2 shows a schematic diagram of a pressing die 300 used to evaluate the ionic conductivity of the solid electrolyte material.

[0159] The pressure molding die 300 had an upper punch 301, a frame 302, and a lower punch 303. The upper punch 301 and the lower punch 303 were both made of electronically conductive stainless steel. The frame 302 was made of insulating polycarbonate.

[0160] The ionic conductivity of the solid electrolyte material of Example A1 was evaluated by the following method using the pressure molding die 300 shown in FIG.

[0161] In a dry argon atmosphere, the powder of the solid electrolyte material according to Example A1 was filled into the inside of a pressure molding die 300. Inside the pressure molding die 300, a pressure of 360 MPa was applied to the powder 101 of the solid electrolyte material according to Example A1 using an upper punch 301 and a lower punch 303.

[0162] While pressure was still applied, the upper punch 301 and the lower punch 303 were connected to a potentiostat (Princeton Applied Research, VersaSTAT4) equipped with a frequency response analyzer. The upper punch 301 was connected to a working electrode and a potential measurement terminal. The lower punch 303 was connected to a counter electrode and a reference electrode. The impedance of the solid electrolyte material was measured at room temperature by electrochemical impedance measurement.

[0163] FIG. 3 is a graph showing a Cole-Cole plot obtained by AC impedance measurement of the solid electrolyte material according to Example A1.

[0164] In Figure 3, the real value of the impedance at the measurement point where the absolute value of the phase of the complex impedance is smallest was considered to be the resistance value for ionic conduction of the solid electrolyte material. The real value is indicated by the arrow R in Figure 3. SE Using the resistance value, the ionic conductivity was calculated based on the following formula (5).

[0165] σ=(R SE ×S / t) -1 ···(5) Here, σ represents ionic conductivity. S represents the contact area of ​​the solid electrolyte material with the punch upper portion 301. In other words, S is equal to the cross-sectional area of ​​the hollow portion of the frame mold 302 in FIG. 2. R SE represents the resistance value of the solid electrolyte material in impedance measurement. t represents the thickness of the solid electrolyte material. That is, t is equal to the thickness of the layer formed from the powder 101 of the solid electrolyte material in FIG. 2.

[0166] The ionic conductivity of the solid electrolyte material according to Example A1 measured at 25°C was 1.24 × 10 -4 It was S / cm.

[0167] (X-ray diffraction measurement) 4 is a graph showing the X-ray diffraction pattern of the solid electrolyte material according to Example A1. The results shown in FIG. 4 were measured by the following method.

[0168] The X-ray diffraction pattern of the solid electrolyte material of Example A1 was measured using an X-ray diffractometer (Rigaku, MiniFlex600) in a dry environment with a dew point of −50° C. Cu-Kα radiation (wavelengths 1.5405 Å and 1.5444 Å) was used as the X-ray source, and the X-ray diffraction pattern was measured by the θ-2θ method.

[0169] In the X-ray diffraction pattern of the solid electrolyte material of Example A1, one peak was present in the range of 13.0° or more and 15.0° or less, and three peaks were present in the range of 26.0° or more and 35.0° or less. Therefore, the solid electrolyte material of Example A1 contained a first crystalline phase (i.e., monoclinic). The observed clear X-ray diffraction peak angles derived from the first crystalline phase are shown in Table 2.

[0170] (Battery construction) In a dry argon atmosphere, the solid electrolyte material according to Example A1 and LiCoO2 were prepared in a volume ratio of 30:70. These materials were mixed in a mortar to obtain a mixture.

[0171] In an insulating tube having an inner diameter of 9.5 mm, the solid electrolyte material of Example A1 (80 mg) and the above mixture (10 mg) were stacked in this order. A pressure of 720 MPa was applied to the resulting stack, forming a solid electrolyte layer made of the solid electrolyte material of Example A1 and a positive electrode made of the above mixture. The solid electrolyte layer had a thickness of 400 μm.

[0172] Next, metal In (thickness 200 μm), metal Li (thickness 200 μm), and metal In (thickness 200 μm) were laminated in this order on the solid electrolyte layer, and a pressure of 80 MPa was applied to the resulting laminate to form a negative electrode.

[0173] Next, current collectors made of stainless steel were attached to the positive and negative electrodes, and current collecting leads were attached to the current collectors.

[0174] Finally, the inside of the insulating cylinder was isolated from the outside atmosphere using an insulating ferrule, and the inside of the cylinder was sealed. In this way, the battery according to Example A1 was obtained.

[0175] (Charge / discharge test) 5 is a graph showing the initial charge / discharge characteristics of the battery according to Example A1. The initial charge / discharge characteristics were measured by the following method.

[0176] The battery according to Example A1 was placed in a thermostatic chamber at 25°C.

[0177] 54μA / cm 2 The battery according to Example A1 was charged until a voltage of 3.68 V was reached at a current density of 0.05 C, which corresponds to a 0.05 C rate.

[0178] Next, 54 μA / cm 2The battery according to Example A1 was discharged at a current density of 0.1 V until a voltage of 1.88 V was reached.

[0179] As a result of the charge-discharge test, the battery according to Example A1 had an initial discharge capacity of 0.97 mAh.

[0180] <Examples A2 to A24> (Preparation of solid electrolyte materials) In Example A2, LiCl, YbCl3, and MgCl2 were prepared as raw material powders in a molar ratio of LiCl:YbCl3:MgCl2=3.1:0.9:0.1.

[0181] In Example A3, LiCl, YbCl3, and ZnCl2 were prepared as raw material powders in a molar ratio of LiCl:YbCl3:ZnCl2=3.1:0.9:0.1.

[0182] In Example A4, LiCl, YbCl3, and ZnCl2 were prepared as raw material powders in a molar ratio of LiCl:YbCl3:ZnCl2=3.2:0.8:0.2.

[0183] In Example A5, LiCl, YbCl3, and ZnCl2 were prepared as raw material powders in a molar ratio of LiCl:YbCl3:ZnCl2=3.3:0.7:0.3.

[0184] In Example A6, LiCl, YbCl3, and ZnCl2 were prepared as raw material powders in a molar ratio of LiCl:YbCl3:ZnCl2=3.4:0.6:0.4.

[0185] In Example A7, LiCl, YbCl3, and ZnCl2 were prepared as raw material powders in a molar ratio of LiCl:YbCl3:ZnCl2=3.5:0.5:0.5.

[0186] In Example A8, LiCl, YbCl3, and ZnCl2 were prepared as raw material powders in a molar ratio of LiCl:YbCl3:ZnCl2=3.2:0.6:0.5.

[0187] In Example A9, LiCl, YbCl3, and ZnCl2 were prepared as raw material powders in a molar ratio of LiCl:YbCl3:ZnCl2=3:0.6:0.6.

[0188] In Example A10, LiCl, YbCl3, and ZnCl2 were prepared as raw material powders in a molar ratio of LiCl:YbCl3:ZnCl2=2.9:0.9:0.2.

[0189] In Example A11, LiCl, YbCl3, and ZnCl2 were prepared as raw material powders in a molar ratio of LiCl:YbCl3:ZnCl2=2.6:1:0.2.

[0190] In Example A12, LiCl, YbCl3, and ZnCl2 were prepared as raw material powders in a molar ratio of LiCl:YbCl3:ZnCl2=2.3:1.1:0.2.

[0191] In Example A13, LiCl, YbCl3, and ZnCl2 were prepared as raw material powders in a molar ratio of LiCl:YbCl3:ZnCl2=2.7:1:0.15.

[0192] In Example A14, LiCl, YbCl3, and ZnCl2 were prepared as raw material powders in a molar ratio of LiCl:YbCl3:ZnCl2=2.8:1:0.1.

[0193] In Example A15, LiCl, YbCl3, and ZnCl2 were prepared as raw material powders in a molar ratio of LiCl:YbCl3:ZnCl2=2.9:1:0.05.

[0194] In Example A16, LiCl, YbCl3, and ZnCl2 were prepared as raw material powders in a molar ratio of LiCl:YbCl3:ZnCl2=3.35:0.75:0.2.

[0195] In Example A17, LiCl, YbCl3, and ZnCl2 were prepared as raw material powders in a molar ratio of LiCl:YbCl3:ZnCl2=3.5:0.7:0.2.

[0196] In Example A18, LiBr, YbCl3, and ZnBr2 were prepared as raw material powders in a molar ratio of LiBr:YbCl3:ZnBr2=2.8:1:0.1.

[0197] In Example A19, LiBr, YbBr3, and ZnBr2 were prepared as raw material powders in a molar ratio of LiBr:YbBr3:ZnBr2=2.8:1:0.1.

[0198] In Example A20, LiBr, LiI, YbCl3, YbI3, and ZnBr2 were prepared as raw material powders in a molar ratio of LiBr:LiI:YbCl3:YbBr3:ZnBr2=0.8:2:0.67:0.33:0.1.

[0199] In Example A21, LiBr, LiCl, YbCl3, and ZnCl2 were prepared as raw material powders in a molar ratio of LiBr:LiCl:YbCl3:ZnCl2=2:0.8:1:0.1.

[0200] In Example A22, LiBr, LiCl, YbCl3, and MgCl2 were prepared as raw material powders in a molar ratio of LiBr:LiCl:YbCl3:MgCl2=2:0.8:1:0.1.

[0201] In Example A23, LiBr, LiCl, YbCl3, and CaCl2 were prepared as raw material powders in a molar ratio of LiBr:LiCl:YbCl3:CaCl2=2:0.8:1:0.1.

[0202] In Example A24, LiBr, LiCl, YbCl3, and SrCl2 were prepared as raw material powders in a molar ratio of LiBr:LiCl:YbCl3:SrCl2=2:0.8:1:0.1.

[0203] In Examples A2 to A17, the mixture of raw powders was fired at 600° C. for 1 hour in a dry argon atmosphere.

[0204] In Examples A18, A19, and A21 to A24, the mixture of raw powders was calcined at 550° C. for 1 hour in a dry argon atmosphere.

[0205] In Example A20, the mixture of raw powders was fired at 480° C. for 1 hour in a dry argon atmosphere.

[0206] Except for the above, the solid electrolyte materials of Examples A2 to A24 were obtained in the same manner as in Example A1.

[0207] (Evaluation of ionic conductivity) The ionic conductivities of the solid electrolyte materials according to Examples A2 to A24 were measured in the same manner as in Example A1. The measurement results are shown in Table 1.

[0208] (X-ray diffraction measurement) The X-ray diffraction patterns of the solid electrolyte materials according to Examples A2 to A24 were measured in the same manner as in Example A1.

[0209] 4 to 6 are graphs showing the X-ray diffraction patterns of the solid electrolyte materials according to Examples A2 to A24. Specifically, FIG. 4 is a graph showing the X-ray diffraction patterns of the solid electrolyte materials according to Examples A3 to A14 and A16 to A24. FIG. 5 is a graph showing the X-ray diffraction patterns of the solid electrolyte materials according to Examples A2, A3, and A15. FIG. 6 is a graph showing the X-ray diffraction patterns of the solid electrolyte materials according to Examples A8 to A17. Examples A4 to A7 and A18 to A24 contained a first crystalline phase. Example A2 had a second crystalline phase. Example A3 contained a first crystalline phase and a second crystalline phase. Examples A8 to A14, A16, and A17 contained a first crystalline phase and a third crystalline phase. Example A15 contained a second crystalline phase and a third crystalline phase. The observed peak angles from the first, second, and third crystalline phases are shown in Tables 2 to 4, respectively.

[0210] (Charge / discharge test) Using the solid electrolyte materials of Examples A2 to A24, batteries of Examples A2 to A24 were obtained in the same manner as in Example 1. Using the batteries of Examples A2 to A24, charge / discharge tests were carried out in the same manner as in Example A1. As a result, the batteries of Examples A2 to A24 were successfully charged and discharged, similar to the battery of Example A1.

[0211] <Comparative Examples A1 and A2> (Preparation of solid electrolyte materials) In Comparative Example A1, LiCl and YbCl3 were prepared as raw material powders in a molar ratio of LiCl:YbCl3 = 3: 1. The raw material powder mixture was fired at 600°C for 1 hour in a dry argon atmosphere.

[0212] In Comparative Example A2, LiBr and YbBr3 were prepared as raw material powders in a molar ratio of LiBr:YbBr3 = 3: 1. The raw material powder mixture was fired at 550°C for 1 hour in a dry argon atmosphere.

[0213] Except for the above, the solid electrolyte materials according to Comparative Examples A1 and A2 were obtained in the same manner as in Example A1.

[0214] (Evaluation of ionic conductivity) The ionic conductivities of the solid electrolyte materials according to Comparative Examples A1 and A2 were measured in the same manner as in Example A1. The measurement results are shown in Table 1.

[0215] (X-ray diffraction measurement) The X-ray diffraction patterns of the solid electrolyte materials according to Comparative Examples A1 and A2 were measured in the same manner as in Example A1.

[0216] FIG. 5 is a graph showing the X-ray diffraction pattern of the solid electrolyte material according to Comparative Example A1. FIG. A4 is a graph showing the X-ray diffraction pattern of the solid electrolyte material according to Comparative Example A2. The solid electrolyte material according to Comparative Example A1 contained a second crystalline phase. The solid electrolyte material according to Comparative Example A2 contained a first crystalline phase. The observed X-ray diffraction peak angles from the first and second crystalline phases are shown in Tables 2 and 3.

[0217] The compositions of the solid electrolyte materials of Example A and Comparative Example A are shown in Table 1. The values ​​corresponding to a, b, x, and y in composition formula (1), as well as the element type of M, are also shown in Table 1.

[0218] [Table 1]

[0219] [Table 2]

[0220] [Table 3]

[0221] [Table 4]

[0222] <Investigation> The solid electrolyte materials according to Examples A1 to A24 have a high lithium ion conductivity of 5.0×10 -5 S / cm or more near room temperature.

[0223] As is clear from comparing Examples A1 to A24 with Comparative Examples A1 and A2, when the solid electrolyte material is represented by the composition formula (1) and contains M in addition to Li, Yb, and X, the solid electrolyte has significantly higher ionic conductivity compared to the case where M is not contained. This is presumably because when the solid electrolyte material contains M, it becomes easier to form a path for lithium ions to diffuse within the crystal lattice.

[0224] As is clear from comparing Examples A1 to A6 with Example A7, when 0 < b and a + b = 1 (i.e., Yb is partially substituted by M), and b ≤ 0.4 is satisfied, the solid electrolyte material has even higher ionic conductivity. This is presumably because when the value of b increases, a crystal phase different from the first, second, and third crystal phases, which tend to have high lithium ion conductivity, precipitates. In the X-ray diffraction pattern of the solid electrolyte material according to Example 7, diffraction peaks derived from Li2ZnCl4 were observed.

[0225] As is clear from comparing Examples A4, A10, and A11 with Examples A12, A16, and A17, when b = 0.2 is satisfied, the solid electrolyte material has higher ionic conductivity when 0.8 ≤ a ≤ 1. This is presumably because Li, which is an ion conduction carrier, and Yb and M, which form the framework of the crystal lattice (i.e., the ion conduction path), are in an optimal quantitative relationship.

[0226] As is clear from a comparison of Example A11 with Examples A13, A14, and A15, when a = 1 is satisfied, the solid electrolyte material has higher ionic conductivity when b = 0.2, which is thought to be due to the formation of lithium ion vacancies, which facilitate the diffusion of lithium ions.

[0227] As is clear from a comparison of Examples A18, A20, and A21 with Examples A14 and A19, when X contains two or more elements, the solid electrolyte material has significantly higher ionic conductivity. This is thought to be because the size of the YbX6 octahedron in the crystal lattice is optimized, making it easier to form lithium ion conduction paths.

[0228] As is clear from a comparison of Examples A2, A3, and A21 to A24, the solid electrolyte material has higher ionic conductivity when M is Zn. This is thought to be because, among Mg, Ca, Sr, and Zn, Zn has the closest ionic radius to Yb, and therefore strain that inhibits lithium ion conduction is less likely to be introduced into the crystal lattice.

[0229] The batteries according to Examples A1 to A24 were charged and discharged at room temperature.

[0230] The solid electrolyte materials of Examples A1 to A24 did not contain sulfur and therefore did not generate hydrogen sulfide.

[0231] The solid electrolyte material according to Example B can be represented by the above-mentioned composition formula (2).

[0232] Example B1 (Preparation of solid electrolyte materials) In a dry argon atmosphere, raw material powders of LiCl, LiBr, YbCl3, and YCl3 were prepared in a molar ratio of LiCl:LiBr:YbCl3:YCl3 = 2:1:0.9:0.1. These raw material powders were ground and mixed in an agate mortar. The resulting mixed powder was placed in an alumina crucible and fired at 550°C for 1 hour in a dry argon atmosphere. The resulting fired product was ground in the agate mortar. In this way, a powder of the solid electrolyte material according to Example 1 was obtained. The solid electrolyte material according to Example B1 was composed of Li3Yb 0.9 Y 0.1 It had a composition represented by Br1Cl5.

[0233] (Evaluation of ionic conductivity) The ionic conductivity of the solid electrolyte material of Example B1 was evaluated in the same manner as in Example A1.

[0234] FIG. 8 is a graph showing a Cole-Cole plot obtained by AC impedance measurement of the solid electrolyte material according to Example B1.

[0235] The ionic conductivity of the solid electrolyte material according to Example B1 measured at 25°C was 1.20 × 10 -3 It was S / cm.

[0236] (X-ray diffraction measurement) 9 is a graph showing the X-ray diffraction pattern of the solid electrolyte material according to Example B1. The results shown in FIG. 9 were measured in the same manner as in Example A1.

[0237] In the X-ray diffraction pattern of the solid electrolyte material according to Example B1, one peak was present in the range of 13.0° or more and 15.0° or less, and two peaks were present in the range of 26.0° or more and 35.0° or less. Therefore, the solid electrolyte material according to Example B1 contained a fifth crystalline phase (i.e., monoclinic crystals). The distinct X-ray diffraction peak angles from the fifth crystalline phase observed are shown in Table 6.

[0238] (Battery construction) A battery according to Example B1 was obtained in the same manner as in Example A1, except that the solid electrolyte material according to Example B1 was used instead of the solid electrolyte material according to Example A1.

[0239] (Charge / discharge test) 11 is a graph showing the initial charge-discharge characteristics of the battery according to Example B1. The initial charge-discharge characteristics were measured in the same manner as in Example A1.

[0240] As a result of the charge-discharge test, the battery according to Example B1 had an initial discharge capacity of 0.84 mAh.

[0241] <Examples B2 to B33> (Preparation of solid electrolyte materials) In Example B2, LiCl, LiBr, YbCl3, and YCl3 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:YCl3=2:1:0.8:0.2.

[0242] In Example B3, LiCl, LiBr, YbCl3, and YCl3 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:YCl3=2:1:0.7:0.3.

[0243] In Example B4, LiCl, LiBr, YbCl3, and YCl3 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:YCl3=2:1:0.6:0.4.

[0244] In Example B5, LiCl, LiBr, YbCl3, and YCl3 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:YCl3=2:1:0.5:0.5.

[0245] In Example B6, LiCl, LiBr, YbCl3, and YCl3 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:YCl3=2:1:0.3:0.7.

[0246] In Example B7, LiCl, LiBr, YbCl3, and YCl3 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:YCl3=2:1:0.1:0.9.

[0247] In Example B8, LiCl, LiBr, YbCl3, and GdCl3 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:GdCl3=2:1:0.9:0.1.

[0248] In Example B9, LiCl, LiBr, YbCl3, and GdCl3 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:GdCl3=2:1:0.7:0.3.

[0249] In Example B10, LiCl, LiBr, YbCl3, and GdCl3 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:GdCl3=2:1:0.5:0.5.

[0250] In Example B11, LiCl, LiBr, YbCl3, and GdCl3 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:GdCl3=2:1:0.3:0.7.

[0251] In Example B12, LiCl, LiBr, YbCl3, and YCl3 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:YCl3=1:2:0.9:0.1.

[0252] In Example B13, LiCl, LiBr, YbCl3, and YCl3 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:YCl3=1:2:0.7:0.3.

[0253] In Example B14, LiCl, LiBr, YbCl3, and YCl3 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:YCl3=1:2:0.5:0.5.

[0254] In Example B15, LiCl, LiBr, YbCl3, and YCl3 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:YCl3=1:2:0.3:0.7.

[0255] In Example B16, LiCl, LiBr, YbCl3, and YCl3 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:YCl3=1:2:0.1:0.9.

[0256] In Example B17, LiCl, LiBr, YbCl3, and GdCl3 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:GdCl3=1:2:0.9:0.1.

[0257] In Example B18, LiCl, LiBr, YbCl3, and GdCl3 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:GdCl3=1:2:0.7:0.3.

[0258] In Example B19, raw material powders of LiCl, LiBr, YbCl3, and GdCl3 were prepared in a molar ratio of LiCl:LiBr:YbCl3:GdCl3=1:2:0.5:0.5.

[0259] In Example B20, LiCl, LiBr, YbCl3, and GdCl3 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:GdCl3=1:2:0.3:0.7.

[0260] In Example B21, LiCl, LiBr, YbCl3, and YCl3 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:YCl3=1.7:1:0.8:0.3.

[0261] In Example B22, LiCl, LiBr, YbCl3, and YCl3 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:YCl3=1.7:1:0.7:0.4.

[0262] In Example B23, LiCl, YbCl3, and YCl3 were prepared as raw material powders in a molar ratio of LiCl:YbCl3:YCl3=3:0.7:0.3.

[0263] In Example B24, LiBr, YbBr3, and YBr3 were prepared as raw material powders in a molar ratio of LiCl:YbCl3:YCl3=3:0.7:0.3.

[0264] In Example B25, LiCl, LiBr, LiI, YbCl3, and YCl3 were prepared as raw material powders in a molar ratio of LiCl:LiBr:LiI:YbCl3:YCl3=1:1.5:0.5:0.7:0.3.

[0265] In Example B26, LiCl, LiBr, LiI, YbCl3, and YCl3 were prepared as raw material powders in a molar ratio of LiCl:LiBr:LiI:YbCl3:YCl3=1:1.5:0.5:0.5:0.5.

[0266] In Example B27, LiCl, LiBr, LiI, YbCl3, and YCl3 were prepared as raw material powders in a molar ratio of LiCl:LiBr:LiI:YbCl3:YCl3=1:1.5:0.5:0.3:0.7.

[0267] In Example B28, LiCl, LiBr, LiI, YbCl3, and YCl3 were prepared as raw material powders in a molar ratio of LiCl:LiBr:LiI:YbCl3:YCl3=0.5:1.5:1:0.5:0.5.

[0268] In Example B29, LiCl, LiI, YbBr3, and YBr3 were prepared as raw material powders in a molar ratio of LiCl:LiI:YbBr3:YBr3=2:1:0.5:0.5.

[0269] In Example B30, raw material powders of LiCl, LiBr, LiI, YbCl3, and YBr3 were prepared in a molar ratio of LiCl:LiBr:LiI:YbCl3:YBr3=0.5:0.5:2:0.5:0.5.

[0270] In Example B31, raw material powders of LiCl, LiBr, YbCl3, and InCl3 were prepared in a molar ratio of LiCl:LiBr:YbCl3:InCl3=1:2:0.9:0.1.

[0271] In Example B32, LiCl, LiBr, YbCl3, and TbCl3 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:TbCl3=1:2:0.9:0.1.

[0272] In Example B33, LiCl, LiBr, YbCl3, and SmCl3 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:SmCl3=1:2:0.9:0.1.

[0273] In Examples B2 to B22, B24, B32, and B33, the mixture of raw powders was fired at 550° C. for 1 hour in a dry argon atmosphere.

[0274] In Example B23, the mixture of raw material powders was fired at 600° C. for 1 hour in a dry argon atmosphere.

[0275] In Examples B25 to B30, the mixture of raw powders was fired at 480° C. for 1 hour in a dry argon atmosphere.

[0276] In Example B31, the mixture of raw material powders was calcined at 350° C. for 5 hours in a dry argon atmosphere.

[0277] Except for the above, the solid electrolyte materials of Examples B2 to B33 were obtained in the same manner as in Example B1.

[0278] (Evaluation of ionic conductivity) The ionic conductivities of the solid electrolyte materials according to Examples B2 to B33 were measured in the same manner as in Example A1. The measurement results are shown in Table 5.

[0279] (X-ray diffraction measurement) The X-ray diffraction patterns of the solid electrolyte materials according to Examples B2 to B33 were measured in the same manner as in Example A1.

[0280] 9 and 10 are graphs showing the X-ray diffraction patterns of the solid electrolyte materials according to Examples B2 to B33. Specifically, FIG. 9 is a graph showing the X-ray diffraction patterns of the solid electrolyte materials according to Examples B2 to B5, B8 to B10, B12 to B22, and B24 to B33. FIG. 10 is a graph showing the X-ray diffraction patterns of the solid electrolyte materials according to Examples B6, B7, B9 to B11, B19, B20, and B23. Examples B2 to B5, B8, B12 to B18, B21, B22, and B24 to B33 contained the fifth crystalline phase. Examples B6, B7, B11, and B23 contained the sixth crystalline phase. Examples B9, B10, B19, and B20 contained both the fifth and sixth crystalline phases. The observed peak angles from the fifth and sixth crystal phases are shown in Tables 6 and 7, respectively.

[0281] (Charge / discharge test) Using the solid electrolyte materials of Examples B2 to B33, batteries of Examples B2 to B33 were obtained in the same manner as in Example A1. Using the batteries of Examples B2 to B33, charge / discharge tests were carried out in the same manner as in Example A1. As a result, the batteries of Examples B2 to B33 were successfully charged and discharged, similar to the battery of Example B1.

[0282] Comparative Examples B1 and B2 As the solid electrolyte materials according to Comparative Examples B1 and B2, the solid electrolyte materials according to the above-mentioned Comparative Examples A1 and A2 were used, respectively.

[0283] 9 and 10 are graphs showing the X-ray diffraction patterns of the solid electrolyte materials of Comparative Examples B1 and B2. The solid electrolyte material of Comparative Example B2 contained a fifth crystalline phase. The solid electrolyte material of Comparative Example B1 had a structure similar to that of Li3YbCl6 disclosed in ICSD Collection Code 50152. The X-ray diffraction peak angles attributed to the fifth crystalline phase observed in Comparative Example B2 are shown in Table 6.

[0284] The compositions of the solid electrolyte materials according to Example B and Comparative Example B are shown in Table 5. The values ​​corresponding to a, b, x, and y in composition formula (2), as well as the element type of M, are also shown in Table 5.

[0285] [Table 5]

[0286] [Table 6]

[0287] [Table 7]

[0288] <Consideration> The solid electrolyte materials according to Examples B1 to B33 exhibited a thermal conductivity of 5.0×10-5 It has high lithium ion conductivity of over S / cm.

[0289] As is clear from a comparison of Examples B1 to B33 with Comparative Examples B1 and B2, when the solid electrolyte material is represented by composition formula (2) and contains M in addition to Li, Yb, and X, the solid electrolyte has significantly higher ionic conductivity than when it does not contain M. This is thought to be because the inclusion of M in the solid electrolyte material makes it easier to form paths for lithium ions to diffuse within the crystal lattice.

[0290] As is clear from a comparison of Examples B1 to B5 and B8 with Examples B6, B7, B9, and B11, when a = 1, x = 1, and y = 0 are satisfied, the solid electrolyte material has higher ionic conductivity when it is made of the fifth crystalline phase (i.e., when it does not contain the sixth crystalline phase), regardless of the type of element contained in M. This is thought to be because, in the anion sublattice when x ≦ 1 and y = 0 are satisfied, the fifth crystalline phase is more likely to form an appropriate conduction path for lithium ion diffusion than the sixth crystalline phase.

[0291] As is clear from a comparison of Examples B12 to B18 with Examples B19 and B20, when a = 1, x = 2, and y = 0 are satisfied, the solid electrolyte material has high ionic conductivity even when it contains the sixth crystalline phase in addition to the fifth crystalline phase. This is thought to be because, in the anion sublattice when x = 2 and y = 0 are satisfied, the sixth crystalline phase, like the fifth crystalline phase, is likely to form an appropriate conduction path for the diffusion of lithium ions.

[0292] As is clear from a comparison of Examples B2 to B4 with Examples B21 and B22, the solid electrolyte material has higher ionic conductivity when the value of a is 1. This is thought to be because the ionic conductive carrier Li and the Yb and M that form the crystal lattice framework (i.e., the ionic conductive path) are in an optimal relationship in terms of the amount ratio.

[0293] As is clear from comparing Example B3 and B13 with Example B23 and B24, when 0 < x < 6 is satisfied, the solid electrolyte material has higher ionic conductivity. This is presumably because when X contains two or more types of elements, it becomes easier to form a path for lithium ions to diffuse within the crystal lattice.

[0294] As is clear from Examples B25 to B30, even when the value of y is greater than 0, the solid electrolyte material has high ionic conductivity. Also, as is clear from comparing Examples B28 and B29 with Examples B14, B26, and B30, particularly when the value of y is 1, the solid electrolyte material has higher ionic conductivity. This is presumably because when the amount of I is 1 mole, the path for lithium ions to diffuse within the crystal lattice is optimized.

[0295] As is clear from comparing Examples B12, B17, B31, B32, and B33 with each other, when M is Y, Gd, Tb, or Sm, the solid electrolyte material has higher ionic conductivity. When M is Y, Gd, or Tb, the solid electrolyte material has even higher ionic conductivity.

[0296] The batteries according to Examples B1 to B33 were charged and discharged at room temperature.

[0297] Since the solid electrolyte materials according to Examples B1 to B33 do not contain sulfur, hydrogen sulfide was not generated.

[0298] The solid electrolyte material according to Example C can be represented by the above composition formula (3).

[0299] <Example C1> (Production of Solid Electrolyte Material) In a dry argon atmosphere, raw material powders of LiCl, YbCl3, and ZrCl4 were prepared in a molar ratio of LiCl:YbCl3:ZrCl4 = 2.9:0.9:0.1. These raw material powders were pulverized and mixed in an agate mortar. The resulting mixed powder was milled at 500 rpm for 12 hours using a planetary ball mill. In this way, powder of the solid electrolyte material according to Example 1 was obtained. The solid electrolyte material according to Example C1 contained Li 2.9 Yb 0.9 Zr 0.1 It had a composition represented by Cl6.

[0300] (Evaluation of ionic conductivity) The ionic conductivity of the solid electrolyte material of Example C1 was evaluated in the same manner as in Example A1.

[0301] The ionic conductivity of the solid electrolyte material according to Example C1 measured at 25°C was 3.76 x 10 -4 It was S / cm.

[0302] (X-ray diffraction measurement) 13 is a graph showing the X-ray diffraction pattern of the solid electrolyte material according to Example C1. The results shown in FIG. 13 were measured in the same manner as in Example A1.

[0303] The solid electrolyte material of Example C1 had at least one peak in the X-ray diffraction pattern in the diffraction angle 2θ ranges of 14.0° to 18.0°, 29.0° to 35.0°, and 48.0° to 52.0°. Therefore, the solid electrolyte material of Example C1 contained the 8th crystalline phase. The observed X-ray diffraction peak angles derived from the 8th crystalline phase are shown in Table 9.

[0304] (Battery construction) A battery according to Example C1 was obtained in the same manner as in Example A1, except that the solid electrolyte material according to Example C1 was used instead of the solid electrolyte material according to Example A1.

[0305] (Charge / discharge test) 15 is a graph showing the initial charge-discharge characteristics of the battery according to Example C1. The initial charge-discharge characteristics were measured in the same manner as in Example A1.

[0306] As a result of the charge-discharge test, the battery according to Example C1 had an initial discharge capacity of 0.86 mAh.

[0307] <Examples C2 to C24> (Preparation of solid electrolyte materials) In Example C2, LiCl, YbCl3, and ZrCl4 were prepared as raw material powders in a molar ratio of LiCl:YbCl3:ZrCl4=2.7:0.7:0.3.

[0308] In Example C3, LiCl, YbCl3, and ZrCl4 were prepared as raw material powders in a molar ratio of LiCl:YbCl3:ZrCl4=2.5:0.5:0.5.

[0309] In Example C4, LiCl, YbCl3, and ZrCl4 were prepared as raw material powders in a molar ratio of LiCl:YbCl3:ZrCl4=2.1:0.1:0.9.

[0310] In Example C5, LiCl, LiBr, YbCl3, and ZrCl4 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:ZrCl4=0.5:2:0.5:0.5.

[0311] In Example C6, LiBr, YbCl3, YbBr3, and ZrCl4 were prepared as raw material powders in a molar ratio of LiBr:YbCl3:YbBr3:ZrCl4=2.5:0.33:0.17:0.5.

[0312] In Example C7, LiBr, YbBr3, and ZrCl4 were prepared as raw material powders in a molar ratio of LiBr:YbBr3:ZrCl4=2.5:0.5:0.5.

[0313] In Example C8, LiBr, YbBr3, and ZrBr4 were prepared as raw material powders in a molar ratio of LiBr:YbBr3:ZrBr4=2.5:0.5:0.5.

[0314] In Example C9, raw material powders of LiCl, LiBr, LiI, YbCl3, and ZrCl4 were prepared in a molar ratio of LiCl:LiBr:LiI:YbCl3:ZrCl4=0.5:1:1:0.5:0.5.

[0315] In Example C10, LiBr, LiI, YbCl3, YbBr3, and ZrCl4 were prepared as raw material powders in a molar ratio of LiBr:LiI:YbCl3:YbBr3:ZrCl4=0.5:2:0.33:0.17:0.5.

[0316] In Example C11, LiCl, YbCl3, and HfCl4 were prepared as raw material powders in a molar ratio of LiCl:YbCl3:HfCl4=2.9:0.9:0.1.

[0317] In Example C12, LiCl, YbCl3, and HfCl4 were prepared as raw material powders in a molar ratio of LiCl:YbCl3:HfCl4=2.5:0.5:0.5.

[0318] In Example C13, LiCl, YbCl3, and HfCl4 were prepared as raw material powders in a molar ratio of LiCl:YbCl3:HfCl4=2.1:0.1:0.9.

[0319] In Example C14, LiCl, LiBr, YbCl3, and HfCl4 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:HfCl4=0.5:2:0.5:0.5.

[0320] In Example C15, LiBr, YbCl3, YbBr3, and HfCl4 were prepared as raw material powders in a molar ratio of LiBr:YbCl3:YbBr3:HfCl4=2.5:0.33:0.17:0.5.

[0321] In Example C16, LiCl, YbCl3, and ZrCl4 were prepared as raw material powders in a molar ratio of LiCl:YbCl3:ZrCl4=2.4:0.8:0.3.

[0322] In Example C17, LiCl, YbCl3, and ZrCl4 were prepared as raw material powders in a molar ratio of LiCl:YbCl3:ZrCl4=2.3:0.7:0.4.

[0323] In Example C18, LiCl, YbCl3, and ZrCl4 were prepared as raw material powders in a molar ratio of LiCl:YbCl3:ZrCl4=2.2:0.6:0.5.

[0324] In Example C19, LiCl, YbCl3, and ZrCl4 were prepared as raw material powders in a molar ratio of LiCl:YbCl3:ZrCl4=2.9:0.5:0.4.

[0325] In Example C20, LiCl, YbCl3, and ZrCl4 were prepared as raw material powders in a molar ratio of LiCl:YbCl3:ZrCl4=2.8:0.4:0.5.

[0326] In Example C21, LiCl, YbCl3, and ZrCl4 were prepared as raw material powders in a molar ratio of LiCl:YbCl3:ZrCl4=2.7:0.3:0.6.

[0327] In Example C22, LiCl, YbCl3, and ZrCl4 were prepared as raw material powders in a molar ratio of LiCl:YbCl3:ZrCl4=2.5:0.7:0.35.

[0328] In Example C23, LiCl, YbCl3, and ZrCl4 were prepared as raw material powders in a molar ratio of LiCl:YbCl3:ZrCl4=2.4:0.6:0.45.

[0329] In Example C24, LiCl, YbCl3, and ZrCl4 were prepared as raw material powders in a molar ratio of LiCl:YbCl3:ZrCl4=2.45:0.55:0.5.

[0330] Except for the above, the solid electrolyte materials of Examples C2 to C24 were obtained in the same manner as in Example C1.

[0331] (Evaluation of ionic conductivity) The ionic conductivities of the solid electrolyte materials according to Examples C2 to C24 were measured in the same manner as in Example A1. The measurement results are shown in Table 8.

[0332] (X-ray diffraction measurement) The X-ray diffraction patterns of the solid electrolyte materials according to Examples C2 to C15 were measured in the same manner as in Example A1.

[0333] Figure 13 is a graph showing the X-ray diffraction patterns of the solid electrolyte materials of Examples C2 to C4 and C11 to C13. Figure 14 is a graph showing the X-ray diffraction patterns of the solid electrolyte materials of Examples C5 to C10, C14, and C15. Examples C2 to C4 and C11 to C13 contained the 8th crystalline phase. Examples C5 to C10, C14, and C15 contained the 9th crystalline phase. The peak angles observed from the 8th and 9th crystalline phases are shown in Tables 9 and 10, respectively.

[0334] (Charge / discharge test) Using the solid electrolyte materials of Examples C2 to C24, batteries of Examples C2 to C24 were obtained in the same manner as in Example A1. Using the batteries of Examples C2 to C24, charge / discharge tests were carried out in the same manner as in Example A1. As a result, the batteries of Examples C2 to C24 were successfully charged and discharged, similar to the battery of Example C1.

[0335] Comparative Examples C1 and C2 The solid electrolyte materials according to the above-mentioned comparative examples A1 and A2 were used as the solid electrolyte materials according to comparative examples C1 and C2, respectively.

[0336] The compositions of the solid electrolyte materials according to Example C and Comparative Example C are shown in Table 8. The values ​​corresponding to a, b, x, and y in composition formula (3), as well as the element type of M, are also shown in Table 8.

[0337] [Table 8]

[0338] [Table 9]

[0339] [Table 10]

[0340] <Consideration> The solid electrolyte materials according to Examples C1 to C24 exhibited a thermal conductivity of 5.0 × 10 -5 It has high lithium ion conductivity of over S / cm.

[0341] As is clear from a comparison of Examples C1 to C24 with Comparative Examples C1 and C2, when the solid electrolyte material is represented by composition formula (3) and contains M in addition to Li, Yb, and X, the solid electrolyte material has significantly higher ionic conductivity than when it does not contain M. This is thought to be because the inclusion of M in the solid electrolyte material makes it easier to form paths for the diffusion of lithium ions. In the examples, Zr or Hf was included as M.

[0342] Comparing Examples C2 to C4, C12, and C13 with Examples C1 and C11, it is clear that when Yb is substituted with M by 30% or more (i.e., a≦0.7 and b≧0.3), the solid electrolyte material has higher ionic conductivity, which is believed to be due to the formation of a significant amount of lithium ion vacancies in the crystal lattice, which facilitates the diffusion of lithium ions.

[0343] Comparing Example C3 with Examples C2 and C4, and Example C12 with Example C13, it is clear that when Yb is substituted with M by 50% (i.e., a=0.5 and b=0.5), the solid electrolyte material has significantly higher ionic conductivity. This is thought to be due to the optimization of the ratio of the amount of lithium ions to the amount of lithium ion vacancies in the crystal lattice.

[0344] As is clear from a comparison of Examples C3, C5 to C8, C12, C14, and C15, when y = 0 is satisfied, the smaller the value of x, the higher the ionic conductivity of the solid electrolyte material. This is thought to be because the width of the lithium ion conduction path in the crystal lattice becomes narrower as Br, which has a larger ionic radius than Cl, increases, making it difficult for lithium ions to diffuse.

[0345] As is clear from a comparison of Examples C9 and C10 with Examples C5 and C6, when y > 0 is satisfied, the solid electrolyte material has higher ionic conductivity. This is thought to be because the introduction of I, which has high polarizability, into the crystal lattice makes it easier for lithium ions to diffuse.

[0346] As is clear from Examples C16 to C24, even when M does not substitute at the same site as Yb in the crystal lattice (i.e., a+b>1) or when Li occupies the same site as Yb (i.e., a+b<1), the solid electrolyte material has high ionic conductivity.

[0347] As is clear from a comparison of Examples C16 to C18 and C22 to C24 with Examples C19 to C21, when a + b > 1 is satisfied, the solid electrolyte material has higher ionic conductivity than when a + b < 1 is satisfied. This is thought to be because when a + b > 1 is satisfied, paths for lithium ions to diffuse are more easily formed within the crystal lattice.

[0348] As is clear from a comparison of Examples C22 to C24 with Examples C16 to C18, when a+b=1.05 is satisfied, the solid electrolyte material has higher ionic conductivity than when a+b=1.1 is satisfied, which is thought to be due to the optimization of the amount of lithium ions in the crystal lattice.

[0349] The batteries according to Examples C1 to C24 were charged and discharged at room temperature.

[0350] The solid electrolyte materials of Examples C1 to C24 did not contain sulfur and therefore did not generate hydrogen sulfide.

[0351] The solid electrolyte material according to Example D can be represented by the above-mentioned composition formula (4).

[0352] Example D1 (Preparation of solid electrolyte materials) In a dry argon atmosphere, raw material powders of LiCl, LiBr, YbCl3, YCl3, and ZnCl2 were prepared in a molar ratio of LiCl:LiBr:YbCl3:YCl3:ZnCl2 = 2.15:1:0.65:0.2:0.15. These raw material powders were ground and mixed in an agate mortar. The resulting mixed powder was placed in an alumina crucible and fired at 550°C for 1 hour in a dry argon atmosphere. The resulting fired product was ground in the agate mortar. In this way, a powder of the solid electrolyte material according to Example D1 was obtained. The solid electrolyte material according to Example 1 contained Li 3.15 Yb 0.65 Y 0.2 Zn 0.15 It had a composition represented by Br1Cl5.

[0353] (Evaluation of ionic conductivity) The ionic conductivity of the solid electrolyte material of Example D1 was evaluated in the same manner as in Example A1.

[0354] FIG. 16 is a graph showing a Cole-Cole plot obtained by AC impedance measurement of the solid electrolyte material according to Example D1.

[0355] The ionic conductivity of the solid electrolyte material according to Example D1 measured at 25°C was 6.25 × 10 -4 It was S / cm.

[0356] (X-ray diffraction measurement) 17 is a graph showing the X-ray diffraction pattern of the solid electrolyte material according to Example D1. The results shown in FIG. 17 were measured in the same manner as in Example A1.

[0357] In the X-ray diffraction pattern of the solid electrolyte material of Example D1, one peak was present in the range of 13.0° or more and 15.0° or less, and two peaks were present in the range of 26.0° or more and 35.0° or less. Therefore, the solid electrolyte material of Example D1 contained the 11th crystalline phase (i.e., monoclinic). The observed distinct X-ray diffraction peak angles from the 11th crystalline phase are shown in Table 12.

[0358] (Battery construction) A battery according to Example D1 was obtained in the same manner as in Example A1, except that the solid electrolyte material according to Example D1 was used instead of the solid electrolyte material according to Example A1.

[0359] (Charge / discharge test) 19 is a graph showing the initial charge-discharge characteristics of the battery according to Example D1. The initial charge-discharge characteristics were measured in the same manner as in Example A1.

[0360] As a result of the charge-discharge test, the battery according to Example D1 had an initial discharge capacity of 0.93 mAh.

[0361] <Examples D2 to D27> (Preparation of solid electrolyte materials) In Example D2, raw material powders of LiCl, LiBr, YbCl3, YCl3, and MgCl2 were prepared in a molar ratio of LiCl:LiBr:YbCl3:YCl3:MgCl2=2.15:1:0.65:0.2:0.15.

[0362] In Example D3, raw material powders of LiCl, LiBr, YbCl3, YCl3, and CaCl2 were prepared in a molar ratio of LiCl:LiBr:YbCl3:YCl3:CaCl2=2.15:1:0.65:0.2:0.15.

[0363] In Example D4, LiCl, LiBr, YbCl3, YCl3, and ZnCl2 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:YCl3:ZnCl2=1.8:1:0.7:0.3:0.1.

[0364] In Example D5, LiCl, LiBr, YbCl3, YCl3, and MgCl2 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:YCl3:MgCl2=1.8:1:0.7:0.3:0.1.

[0365] In Example D6, LiCl, LiBr, YbCl3, YCl3, and CaCl2 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:YCl3:CaCl2=1.8:1:0.7:0.3:0.1.

[0366] In Example D7, LiCl, LiBr, YbCl3, YCl3, and SrCl2 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:YCl3:SrCl2=1.8:1:0.7:0.3:0.1.

[0367] In Example D8, LiCl, LiBr, YbCl3, YCl3, and ZnCl2 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:YCl3:ZnCl2=0.2:3:0.7:0.1:0.2.

[0368] In Example D9, LiCl, LiBr, YbCl3, InCl3, and ZnCl2 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:InCl3:ZnCl2=0.2:3:0.7:0.1:0.2.

[0369] In Example D10, raw material powders of LiCl, LiBr, YbCl3, TbCl3, and ZnCl2 were prepared in a molar ratio of LiCl:LiBr:YbCl3:TbCl3:ZnCl2=0.2:3:0.7:0.1:0.2.

[0370] In Example D11, LiCl, LiBr, YbCl3, GdCl3, and ZnCl2 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:GdCl3:ZnCl2=0.2:3:0.7:0.1:0.2.

[0371] In Example D12, raw material powders of LiCl, LiBr, YbCl3, SmCl3, and ZnCl2 were prepared in a molar ratio of LiCl:LiBr:YbCl3:SmCl3:ZnCl2=0.2:3:0.7:0.1:0.2.

[0372] In Example D13, raw material powders of LiCl, YbCl3, YCl3, and ZnCl2 were prepared in a molar ratio of LiCl:YbCl3:YCl3:ZnCl2=3.2:0.7:0.1:0.2.

[0373] In Example D14, LiBr, YbBr3, YBr3, and ZnBr2 were prepared as raw material powders in a molar ratio of LiBr:YbBr3:YBr3:ZnBr2=3.2:0.7:0.1:0.2.

[0374] In Example D15, LiCl, LiBr, YbCl3, YCl3, and ZnCl2 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:YCl3:ZnCl2=2.2:1:0.7:0.1:0.2.

[0375] In Example D16, LiCl, LiBr, YbCl3, YCl3, and ZnCl2 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:YCl3:ZnCl2=2.1:1:0.65:0.25:0.1.

[0376] In Example D17, LiCl, LiBr, YbCl3, YCl3, and ZnCl2 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:YCl3:ZnCl2=2.1:1:0.8:0.1:0.1.

[0377] In Example D18, LiCl, LiBr, YbCl3, YCl3, and ZnCl2 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:YCl3:ZnCl2=2.1:1:0.7:0.2:0.1.

[0378] In Example D19, raw material powders of LiCl, LiBr, YbCl3, YCl3, and ZnCl2 were prepared in a molar ratio of LiCl:LiBr:YbCl3:YCl3:ZnCl2=2.05:1:0.7:0.25:0.05.

[0379] In Example D20, LiCl, LiBr, YbCl3, YCl3, and ZnCl2 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:YCl3:ZnCl2=1.6:1:0.7:0.3:0.2.

[0380] In Example D21, raw material powders of LiCl, LiBr, YbCl3, YCl3, and ZnCl2 were prepared in a molar ratio of LiCl:LiBr:YbCl3:YCl3:ZnCl2=1.7:1:0.7:0.3:0.15.

[0381] In Example D22, LiCl, LiBr, YbCl3, YCl3, and ZnCl2 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:YCl3:ZnCl2=1.9:1:0.7:0.3:0.05.

[0382] In Example D23, LiCl, LiBr, YbCl3, YCl3, and MgCl2 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:YCl3:MgCl2=2.1:1:0.65:0.25:0.1.

[0383] In Example D24, LiCl, LiBr, YbCl3, YCl3, and MgCl2 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:YCl3:MgCl2=1.7:1:0.7:0.3:0.15.

[0384] In Example D25, raw material powders of LiCl, LiBr, YbCl3, YCl3, and CaCl2 were prepared in a molar ratio of LiCl:LiBr:YbCl3:YCl3:CaCl2=2.1:1:0.65:0.25:0.1.

[0385] In Example D26, LiCl, LiBr, YbCl3, YCl3, and CaCl2 were prepared as raw material powders in a molar ratio of LiCl:LiBr:YbCl3:YCl3:CaCl2=1.9:1:0.7:0.3:0.05.

[0386] In Example D27, raw material powders of LiCl, LiBr, YbCl3, YCl3, and CaCl2 were prepared in a molar ratio of LiCl:LiBr:YbCl3:YCl3:CaCl2=1.7:1:0.7:0.3:0.15.

[0387] In Examples D2 to D8, D10 to D12, and D14 to D27, the mixture of raw powders was fired at 550° C. for 1 hour in a dry argon atmosphere.

[0388] In Example D9, the mixture of raw powders was calcined at 350° C. for 5 hours in a dry argon atmosphere.

[0389] In Example D13, the mixture of raw powders was fired at 600° C. for 1 hour in a dry argon atmosphere.

[0390] Except for the above, the solid electrolyte materials of Examples D2 to D27 were obtained in the same manner as in Example D1.

[0391] (Evaluation of ionic conductivity) The ionic conductivities of the solid electrolyte materials according to Examples D2 to D27 were measured in the same manner as in Example A1. The measurement results are shown in Table 11.

[0392] (X-ray diffraction measurement) The X-ray diffraction patterns of the solid electrolyte materials according to Examples D2 to D27 were measured in the same manner as in Example A1.

[0393] 17 and 18 are graphs showing the X-ray diffraction patterns of the solid electrolyte materials of Examples D2 to D27. Specifically, FIG. 17 is a graph showing the X-ray diffraction patterns of the solid electrolyte materials of Examples D2, D4, D5, D7 to D19, D22 to D24, and D26. FIG. 18 is a graph showing the X-ray diffraction patterns of the solid electrolyte materials of Examples D3, D6, D20 to D22, and D25 to D27. Examples D2, D4, D5, D7 to D19, D23, and D24 contained the 11th crystalline phase. Examples D3, D6, D20, D21, and D25 contained the 12th crystalline phase. Examples D22 and D26 contained the 11th and 12th crystalline phases. The peak angles observed from the 11th and 12th crystalline phases are shown in Tables 12 and 13, respectively.

[0394] (Charge / discharge test) The solid electrolyte materials according to the above-described comparative examples A1 and A2 were used as the solid electrolyte materials according to comparative examples D1 and D2, respectively.

[0395] 17 and 18 are graphs showing the X-ray diffraction patterns of the solid electrolyte materials of Comparative Examples D1 and D2. The solid electrolyte material of Comparative Example D2 contained the 11th crystalline phase. The solid electrolyte material of Comparative Example D1 had a structure similar to that of Li3YbCl6 disclosed in ICSD Collection Code 50152. The X-ray diffraction peak angles attributed to the 11th crystalline phase observed in Comparative Example D2 are shown in Table 12.

[0396] The compositions of the solid electrolyte materials according to Example D and Comparative Example D are shown in Table 11. The values ​​corresponding to a, b, c, x, and y in composition formula (4), as well as the elemental species of M1 and M2, are also shown in Table 11.

[0397] [Table 11]

[0398] [Table 2]

[0399] [Table 3]

[0400] <Consideration> The solid electrolyte materials according to Examples D1 to D27 exhibited a thermal conductivity of 5.0×10 -5 It has high lithium ion conductivity of over S / cm.

[0401] As is clear from a comparison of Examples D1 to D27 with Comparative Examples D1 and D2, when the solid electrolyte material is represented by composition formula (1) and contains M1 and M2 in addition to Li, Yb, and X, the solid electrolyte has significantly higher ionic conductivity than when it does not contain M1 and M2. This is thought to be because the inclusion of M1 and M2 in the solid electrolyte material makes it easier to form paths for lithium ions to diffuse within the crystal lattice.

[0402] As is clear from a comparison of Examples D1, D2, D4, D5, and D7 with Examples D3 and D6, when the solid electrolyte material contains Mg, Sr, or Zn as M2, the solid electrolyte material has particularly high ionic conductivity. This is thought to be because when M2 is Mg, Sr, or Zn, the solid electrolyte material is more likely to form the 11th crystal phase. In the material represented by composition formula (4), the 11th crystal phase is more likely to properly form a conduction path for lithium ion diffusion than the 12th crystal phase.

[0403] As is clear from a comparison of Examples D8 and D10 to D12 with Example D9, when the solid electrolyte material contains Y, Tb, Gd, or Sm as M1, the solid electrolyte material has particularly high ionic conductivity. This is thought to be because when M1 is Y, Tb, Gd, or Sm, which is an element having a larger ionic radius than Yb, paths for lithium ions to diffuse within the crystal lattice are more easily formed.

[0404] As is clear from a comparison of Examples D8 and D13 with Example D14, the solid electrolyte material has higher ionic conductivity when the value of x is 3 or less. This is thought to be because the size of the anion skeleton when the value of x is 3 or less is suitable for lithium ion conduction.

[0405] As is clear from comparing Examples D16 to D19 and D22 with Examples D15, D20, and D21, when M2 is Zn, the solid electrolyte material has higher ionic conductivity when the value of c is 0.1 or less. Furthermore, as is clear from comparing Examples D5 and D23 with Examples D2 and D24, when M2 is Mg, the solid electrolyte material also has higher ionic conductivity when the value of c is 0.1 or less. Furthermore, as is clear from comparing Examples D6, D25, and D26 with Examples D3 and D27, when M2 is Ca, the solid electrolyte material also has higher ionic conductivity when the value of c is 0.1 or less. This is thought to be because divalent cations tend to inhibit the diffusion of lithium ion conduction within the crystal lattice.

[0406] The batteries according to Examples D1 to D27 were charged and discharged at room temperature.

[0407] The solid electrolyte materials according to Examples D1 to D27 did not contain sulfur and therefore did not generate hydrogen sulfide.

[0408] As described above, the solid electrolyte material according to the present disclosure is suitable for providing a battery that has high lithium ion conductivity near room temperature and can be charged and discharged well. [Industrial Applicability]

[0409] The solid electrolyte material and the method for producing the same according to the present disclosure are used, for example, in batteries (for example, all-solid-state lithium-ion secondary batteries). [Explanation of symbols]

[0410] 100 solid electrolyte particles 101 Solid electrolyte material powder 201 Positive electrode 202 Electrolyte layer 203 Negative electrode 204 Positive electrode active material particles 205 Negative electrode active material particles 300 pressure forming die 301 Punch top 302 Frame type 303 Punch bottom 1000 batteries

Claims

1. consisting of Li, Yb, M, and X; M is at least one selected from the group consisting of Mg, Ca, Sr, Ba, Zn, Y, Tb, Gd, Sm, In, Zr, and Hf; X is at least one selected from the group consisting of Cl, Br, and I; Represented by the following composition formula (1): Li6-3a-2bYb aM bCl6-xyBr xI y ... (1) where the following five formulas: 0.2≦a<1.4, 0<b<0.9, 0≦x≦6, 0≦y≦3, and 0≦x+y≦6 is satisfied; Solid electrolyte material.

2. M is at least one selected from the group consisting of Mg, Ca, Sr, Ba, and Zn; The solid electrolyte material according to claim 1 .

3. M is at least one selected from the group consisting of Mg, Ca, Sr, and Zn; The solid electrolyte material according to claim 1 or 2.

4. M contains Zn; The solid electrolyte material according to claim 1 .

5. The formula: 0.5≦a≦1.1 is satisfied; The solid electrolyte material according to claim 1 .

6. The formula: 0<b≦0.6 is satisfied; The solid electrolyte material according to claim 1 .

7. The formula: 0≦y≦2 is satisfied. The solid electrolyte material according to claim 1 .

8. In the X-ray diffraction pattern obtained by X-ray diffraction measurement of the solid electrolyte material using Cu-Kα radiation, At least one peak exists in the diffraction angle 2θ range of 13.0° or more and 15.0° or less, and At least two peaks are present in the diffraction angle 2θ range of 26.0° or more and 35.0° or less. The solid electrolyte material according to claim 1 .

9. In the X-ray diffraction pattern obtained by X-ray diffraction measurement of the solid electrolyte material using Cu-Kα radiation, At least one peak is present in the diffraction angle 2θ range of 22.0° or more and 23.5° or less, At least two peaks are present in the diffraction angle 2θ range of 31.0° or more and 35.0° or less, and At least one peak exists in the diffraction angle 2θ range of 40.0° or more and 42.0° or less. The solid electrolyte material according to claim 1 .

10. In the X-ray diffraction pattern obtained by X-ray diffraction measurement of the solid electrolyte material using Cu-Kα radiation, At least two peaks are present in the diffraction angle 2θ range of 21.0° or more and 24.0° or less, At least two peaks are present in the diffraction angle 2θ range of 31.0° or more and 35.0° or less, and At least one peak exists in the diffraction angle 2θ range of 40.0° or more and 42.0° or less. The solid electrolyte material according to claim 1 .

11. A compound semiconductor comprising Li, Yb, M, and X; M is at least one selected from the group consisting of Y, Tb, Gd, Sm, and In; X is at least one selected from the group consisting of Cl, Br, and I; Represented by the following composition formula (2): Li 6-3a (Yb 1-b M b ) a Cl 6-xy Br x I y ... (2) Here, the following five formulas are satisfied: 0.5≦a≦1.5, 0<b<1, 0≦x≦6, 0≦y≦3, and 0≦x+y≦6 is satisfied; Solid electrolyte material.

12. 12. The solid electrolyte material according to claim 11, wherein M is at least one selected from the group consisting of Y, Tb, Gd, and Sm.

13. The formula: 1≦a≦1.1 is satisfied; The solid electrolyte material according to claim 11 or 12.

14. The formula: 0≦y≦2 is satisfied. The solid electrolyte material according to any one of claims 11 to 13.

15. In the X-ray diffraction pattern obtained by X-ray diffraction measurement of the solid electrolyte material using Cu-Kα radiation, At least one peak exists in the diffraction angle 2θ range of 13.0° or more and 15.0° or less, and At least two peaks are present in the diffraction angle 2θ range of 26.0° or more and 35.0° or less. The solid electrolyte material according to any one of claims 11 to 14.

16. In the X-ray diffraction pattern obtained by X-ray diffraction measurement of the solid electrolyte material using Cu-Kα radiation, At least two peaks are present in the diffraction angle 2θ range of 20.5° or more and 24.0° or less, At least two peaks are present in the diffraction angle 2θ range of 30.0° or more and 35.0° or less, and At least one peak exists in the diffraction angle 2θ range of 39.0° or more and 42.0° or less. The solid electrolyte material according to any one of claims 11 to 14.

17. A compound semiconductor comprising Li, Yb, M, and X; M is at least one selected from the group consisting of Zr and Hf; X is at least one selected from the group consisting of Cl, Br, and I; Represented by the following composition formula (3): Li 6-3a-4b Yb a M b Cl 6-xy Br x I y ... (3) Here, the following six equations: 0<a<1.5, 0<b<1.5, 0<3a+4b<6 0≦x≦6, 0≦y≦3, and 0≦x+y≦6 is satisfied; Solid electrolyte material.

18. The formula: 0<a<1 is satisfied. The solid electrolyte material according to claim 17.

19. The formula: 0<b<1 is satisfied. The solid electrolyte material according to claim 17 or 18.

20. The formula: 0≦x≦3 is satisfied; The solid electrolyte material according to any one of claims 17 to 19.

21. The formula: 0≦y≦2 is satisfied. The solid electrolyte material according to any one of claims 17 to 20.

22. In the X-ray diffraction pattern obtained by X-ray diffraction measurement of the solid electrolyte material using Cu-Kα radiation, At least one peak is present in each of the diffraction angle 2θ ranges of 14.0° or more and 18.0° or less, 29.0° or more and 35.0° or less, and 48.0° or more and 52.0° or less. The solid electrolyte material according to any one of claims 17 to 21.

23. In the X-ray diffraction pattern obtained by X-ray diffraction measurement of the solid electrolyte material using Cu-Kα radiation, At least two peaks are present in the diffraction angle 2θ range of 26.0° or more and 35.0° or less, and At least one peak exists in the diffraction angle 2θ range of 13.0° or more and 17.0° or less. The solid electrolyte material according to any one of claims 17 to 21.

24. A compound semiconductor comprising: Li, Yb, M, and X; M consists of M1 and M2, M1 is at least one selected from the group consisting of Y, Tb, Gd, Sm, and In; M2 is at least one selected from the group consisting of Mg, Ca, Sr, Ba, and Zn; X is at least one selected from the group consisting of F, Cl, Br, and I; Solid electrolyte material.

25. M1 is one selected from the group consisting of Y, Tb, Gd, and Sm; The solid electrolyte material according to claim 24.

26. M2 is at least one selected from the group consisting of Mg, Ca, Sr, and Zn; The solid electrolyte material according to claim 24 or 25.

27. X is at least one selected from the group consisting of Cl and Br; The solid electrolyte material according to any one of claims 24 to 26.

28. Represented by the following composition formula (4): Li 6-3a-3b-2c Yb a M1 b M2 c Cl 6-x Br x ・・・(4) Here, the following four equations: 0.3≦a≦1.2, 0<b≦0.5, 0<c≦0.4, and 0≦x≦6 is satisfied; The solid electrolyte material according to any one of claims 24 to 27.

29. The formula: 0.65≦a<1 is satisfied; The solid electrolyte material according to claim 28.

30. The formula: 0<b≦0.3 is satisfied; The solid electrolyte material according to claim 28 or 29.

31. The formula: 0<c≦0.2 is satisfied; The solid electrolyte material according to any one of claims 28 to 30.

32. In the X-ray diffraction pattern obtained by X-ray diffraction measurement of the solid electrolyte material using Cu-Kα radiation, At least one peak exists in the diffraction angle 2θ range of 13.0° or more and 15.0° or less, and 32. The solid electrolyte material according to any one of claims 24 to 31, wherein at least two peaks are present in a diffraction angle 2θ range of 26.0° or more and 35.0° or less.

33. In the X-ray diffraction pattern obtained by X-ray diffraction measurement of the solid electrolyte material using Cu-Kα radiation, At least two peaks are present in the diffraction angle 2θ range of 20.5° or more and 24.0° or less, At least two peaks are present in the diffraction angle 2θ range of 30.0° or more and 35.0° or less, and At least one peak exists in the diffraction angle 2θ range of 39.0° or more and 42.0° or less. The solid electrolyte material according to any one of claims 24 to 31.

34. positive electrode, a negative electrode, and an electrolyte layer disposed between the positive electrode and the negative electrode; Equipped with At least one selected from the group consisting of the positive electrode, the negative electrode, and the electrolyte layer contains the solid electrolyte material according to any one of claims 1 to 33. battery.

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