Method for producing halide

Abstract

The production method according to the present disclosure comprises a firing step for firing a mixed material comprising (NH4)aYα3+a, (NH4)bGdβ3+b, Liγ and Caδ2 under an inert gas atmosphere, in which α, β, γ and δ independently represent at least one atom selected from the group consisting of F, Cl, Br and I and the formulae: 0 ≦ a ≦ 3, 0 ≦ b ≦ 3 and 0 < a+b ≦ 6 are satisfied.

Description

Technical Field

[0001] The present disclosure relates to a method for producing a halide.

Background Art

[0002] Patent Document 1 discloses a method for producing a halide solid electrolyte.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present disclosure is to provide a method for producing a halide with high industrial productivity.

Means for Solving the Problems

[0005] The production method of the present disclosure includes a firing step of firing a mixed material containing (NH4) a Yα 3+a , (NH4) b Gdβ 3+b , Liγ, and Caδ2 in an inert gas atmosphere. Here, α, β, γ, and δ are each independently at least one selected from the group consisting of F, Cl, Br, and I, and further, 0 ≦ a ≦ 3, 0 ≦ b ≦ 3, and 0 < a + b ≦ 6 are satisfied.

Effects of the Invention

[0006] The present disclosure provides a method for producing a halide with high industrial productivity.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments will be described with reference to the drawings.

[0009] (First Embodiment) FIG. 1 is a flowchart showing an example of a manufacturing method according to the first embodiment.

[0010] The manufacturing method according to the first embodiment includes a firing step S1000. In the firing step S1000, the mixed material is fired in an inert gas atmosphere.

[0011] The mixed material fired in the firing step S1000 is a material containing (NH4) a Yα 3+a , (NH4) b Gdβ 3+b , Liγ, and Caδ2. Here, α, β, γ, and δ are each independently at least one selected from the group consisting of F, Cl, Br, and I. Further, the mathematical formulas: 0 ≦ a ≦ 3, 0 ≦ b ≦ 3, and 0 < a + b ≦ 6 are satisfied.

[0012] The manufacturing method according to the first embodiment is an industrially highly productive method for manufacturing a halide. An industrially highly productive method is, for example, a method that can be produced in large quantities at low cost. That is, a halide containing Li (i.e., lithium), Y (i.e., yttrium), Gd (i.e., gadolinium), and Ca (i.e., calcium) can be manufactured by a simple manufacturing method (i.e., firing in an inert gas atmosphere).

[0013] The manufacturing method according to the first embodiment does not have to use a vacuum sealed tube and a planetary ball mill.

[0014] (NH4) a Yα 3+a included in the mixed material can be easily synthesized from inexpensive Y2O3 and NH4α, so the manufacturing cost can be further reduced.

[0015] (NH4) b Gdβ 3+b included in the mixed material can be easily synthesized from inexpensive Gd2O3 and NH4β, so the manufacturing cost can be further reduced.

[0016] In order to increase the ionic conductivity of the halide, the mathematical formulas: 0.5 ≦ a ≦ 3 and 0.5 ≦ b ≦ 3 may be satisfied.

[0017] In order to increase the ionic conductivity of the halide, the mathematical formulas: a = 3 and b = 3 may be satisfied.

[0018] In order to further increase the ionic conductivity of the halide, α, β, γ, and δ may each independently be at least one selected from the group consisting of Cl and Br.

[0019] For example, when the mixed material fired in the firing step S1000 contains (NH4)3YCl6, (NH4)3GdCl6, LiCl, and CaCl2, it is considered that the reaction represented by the following formula (1) proceeds.

[0020] 0.5(NH4)3YCl6 + 0.5(NH4)3GdCl6 + 2.8LiCl + 0.1CaCl2 → Li 2.8 Ca 0.1 Y 0.5 Gd 0.5 Cl6 + 3NH3 + 3HCl ···(1)

[0021] By the reaction shown in formula (1), Li 2.8 Ca 0.1 Y 0.5 Gd 0.5 Cl6 is obtained.

[0022] In the firing step S1000, for example, the powder of the mixed material may be placed in a container (e.g., a crucible) and fired in a heating furnace. At this time, the state in which the mixed material is heated to a predetermined temperature in an inert gas atmosphere may be maintained for a predetermined time or longer. The firing time may be a length of time that does not cause a compositional shift of the fired product due to, for example, the volatilization of the halide. Not causing a compositional shift of the fired product means not impairing the ionic conductivity of the fired product. According to the manufacturing method according to the first embodiment, for example, a halide having an ionic conductivity of 2.6×10 -10 S / cm or more can be manufactured near room temperature.

[0023] The inert gas atmosphere means, for example, an atmosphere in which the total concentration of gases other than the inert gas is 1% by volume or less. Examples of the inert gas are helium, nitrogen, or argon.

[0024] After the firing step S1000, the fired product may be pulverized. At this time, a pulverizing device (e.g., a mortar or a mixer) may be used.

[0025] The mixed material may be a material in which (NH4) a Yα 3+a , (NH4) b Gdβ 3+b , Liγ, and Caδ2 are mixed.

[0026] The mixed material is (NH4) a Yα3+a 、 (NH4) b Gdβ 3+b 、 Liγ, and Caδ2 not only, (NH4) a Yα 3+a 、 (NH4) b Gdβ 3+b 、 Liγ, and other materials different from Caδ2 may be further mixed materials.

[0027] (NH4) contained in the mixed material a Yα 3+a 、 (NH4) b Gdβ 3+b 、 At least one selected from the group consisting of Liγ, and Caδ2 may have a part of the metal cation replaced by another metal cation. That is, a part of Y, Gd, Li, and Ca may be replaced by another metal cation. That is, the mixed material is (NH4) a Yα 3+a A compound in which a part of Y is replaced by another metal cation, (NH4) b Gdβ 3+b A compound in which a part of Gd is replaced by another metal cation, a compound in which a part of Li is replaced by another metal cation in Liγ, or a compound in which a part of Ca is replaced by another metal cation in Caδ2 may be further included. Thereby, the properties (for example, ionic conductivity) of the produced halide can be improved. The cation substitution rate of Y, Gd, Li, and Ca by another metal cation may be less than 50 mol%. Thereby, a halide having a more stable structure can be obtained.

[0028] (NH4) contained in the mixed material a Yα 3+a 、 (NH4) b Gdβ 3+bAt least one selected from the group consisting of Liγ and Caδ2 may have a part of the metal cation substituted with at least one cation selected from the group consisting of, for example, Na, K, Mg, Sr, Ba, Zn, In, Sn, Bi, La, Ce, Pr, Nd, Pm, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb, and Lu.

[0029] In the firing step S1000, the mixed material may be fired at 300 °C or higher. Thereby, a halide having high ionic conductivity can be produced by an industrially highly productive method. By setting the firing temperature to 300 °C or higher, the mixed material can be sufficiently reacted. That is, (NH4) a Yα 3+a , (NH4) b Gdβ 3+b , Liγ, and Caδ2 can be sufficiently reacted. Here, the firing temperature is the ambient temperature. When the mixed material is fired at 300 °C or higher, for example, a halide having an ionic conductivity of 7.6×10 -7 S / cm or more can be produced at around room temperature.

[0030] In order to produce a halide having higher ionic conductivity by an industrially highly productive method, the mixed material may be fired at 700 °C or lower. The mixed material may be fired, for example, at 300 °C or higher and 700 °C or lower. By setting the firing temperature to 700 °C or lower, thermal decomposition of the halide produced by the solid-phase reaction can be suppressed. As a result, the ionic conductivity of the fired halide can be increased. That is, a high-quality halide solid electrolyte material can be obtained.

[0031] In order to produce a halide having higher ionic conductivity by an industrially highly productive method, the mixed material may be fired at 350° C. or higher. The mixed material may be fired, for example, at 350° C. or higher and 700° C. or lower. Thereby, the fired halide has higher crystallinity. As a result, the ionic conductivity of the fired halide can be further increased. That is, a higher-quality halide solid electrolyte material can be obtained.

[0032] In order to produce a halide having higher ionic conductivity by an industrially highly productive method, the mixed material may be fired at 650° C. or lower. The mixed material may be fired, for example, at 300° C. or higher and 650° C. or lower, or at 350° C. or higher and 650° C. or lower. Thereby, thermal decomposition of the halide generated by the solid-phase reaction can be suppressed. As a result, the ionic conductivity of the fired halide can be increased. That is, a high-quality halide solid electrolyte material can be obtained.

[0033] In order to produce a halide having higher ionic conductivity by an industrially highly productive method, the mixed material may be fired for 1 hour or more and 72 hours or less. By setting the firing time to 1 hour or more, the mixed material can be sufficiently reacted. That is, (NH4) a Yα 3+a , (NH4) b Gdβ 3+b , Liγ, and Caδ2 can be sufficiently reacted. By setting the firing time to 72 hours or less, volatilization of the fired halide can be suppressed. That is, a halide having the target composition ratio can be obtained. As a result, a decrease in the ionic conductivity of the halide due to compositional deviation can be suppressed. That is, a higher-quality halide solid electrolyte material can be obtained.

[0034] FIG. 2 is a flowchart showing an example of the manufacturing method according to the first embodiment.

[0035] As shown in FIG. 2, the manufacturing method according to the first embodiment may further include a mixing step S1100.

[0036] The mixing step S1100 is performed before the firing step S1000.

[0037] In the mixing step S1100, the raw materials (NH4) a Yα 3+a , (NH4) b Gdβ 3+b , Liγ, and Caδ2 are mixed. Thereby, a mixed material is obtained. That is, the material to be fired in the firing step S1000 is obtained.

[0038] For mixing the raw materials, known mixing instruments (for example, a mortar, a blender, or a ball mill) may be used.

[0039] For example, in the mixing step S1100, powders of the respective raw materials may be prepared and mixed. At this time, in the firing step S1000, the powdered mixed material may be fired. The powdered mixed material obtained in the mixing step S1100 may be formed into pellets by pressing. Alternatively, in the firing step S1000, the pelletized mixed material may be fired.

[0040] In the mixing step S1100, not only (NH4) a Yα 3+a , (NH4) b Gdβ 3+b , Liγ, and Caδ2, but also other raw materials different from (NH4) a Yα 3+a , (NH4) b Gdβ 3+b , Liγ, and Caδ2 may be further mixed to obtain a mixed material.

[0041] In the mixing step S1100, the raw material mainly composed of (NH4) a Yα 3+a , the raw material (NH4) b Gdβ 3+bRaw materials mainly composed of , raw materials mainly composed of Liγ, and raw materials mainly composed of Caδ2 may be mixed. The main component refers to the component contained in the largest amount in terms of molar ratio.

[0042] In the mixing step S1100, (NH4) a Yα 3+a , (NH4) b Gdβ 3+b , Liγ, and Caδ2 may be prepared and mixed so as to have the target composition.

[0043] (NH4)3YCl6, (NH4)3GdCl6, LiCl, and CaCl2 may be mixed, for example, in a molar ratio of (NH4)3YCl6:(NH4)3GdCl6:LiCl:CaCl2 = 0.5:0.5:2.8:0.1. Thereby, a halide having a composition represented by Li 2.8 Ca 0.1 Y 0.5 Gd 0.5 Cl6 can be produced.

[0044] So as to offset the compositional changes that may occur in the firing step S1000, the molar ratios of (NH4) a Yα 3+a , (NH4) b Gdβ 3+b , Liγ, and Caδ2 may be adjusted in advance.

[0045] In the mixing step S1100, (NH4) a Yα 3+a , (NH4) b Gdβ 3+b , at least one selected from the group consisting of Liγ and Caδ2 may have a part of the metal cations substituted by another metal cation. That is, a part of Y, Gd, Li, and Ca may be substituted by another metal cation. That is, in (NH4) a Yα 3+a a compound in which a part of Y is substituted by another metal cation, (NH4) b Gdβ 3+bA compound in which a part of Gd is substituted by another metal cation, a compound in which a part of Li in Liγ is substituted by another metal cation, or a compound in which a part of Ca in Caδ2 is substituted by another metal cation may be further mixed to obtain a mixed material. The cation substitution rate by another metal cation of Y, Gd, Li, and Ca may be less than 50 mol%.

[0046] Figure 3 is a flowchart showing an example of the manufacturing method according to the first embodiment.

[0047] As shown in Figure 3, the manufacturing method according to the first embodiment may further include a preparation step S1200.

[0048] The preparation step S1200 is executed before the mixing step S1100.

[0049] In the preparation step S1200, (NH4) a Yα 3+a and (NH4) b Gdβ 3+b are prepared. In the preparation step S1200, Liγ and Caδ2 may be further prepared. That is, the materials to be mixed in the mixing step S1100 may be prepared.

[0050] In the preparation step S1200, (NH4) a Yα 3+a , (NH4) b Gdβ 3+b , Liγ, or raw materials such as Caδ2 may be synthesized. Alternatively, in the preparation step S1200, known commercially available products (for example, materials with a purity of 99% or more) may be used.

[0051] The prepared material may be dry.

[0052] Examples of the shape of the material to be prepared are crystalline, massive, flaky, or powdery. In the preparation step S1200, a powdery raw material may be obtained by pulverizing a crystalline or massive or flaky raw material.

[0053] To reduce the manufacturing cost, in the preparation step S1200, (NH4) a Yα 3+a may be synthesized from inexpensive Y2O3 and NH4α.

[0054] To reduce the manufacturing cost, in the preparation step S1200, (NH4) a Gdβ 3+a may be synthesized from inexpensive Gd2O3 and NH4β.

[0055] (NH4) a Yα 3+a is synthesized, for example, as follows.

[0056] Y2O3 and NH4α are mixed as raw materials so as to have a Y2O3:NH4α molar ratio of, for example, 1:12 to obtain a mixture. The mixture is fired at, for example, 150 °C or higher and 350 °C or lower. The value of a above may vary depending on the firing temperature.

[0057] For example, when α is Cl, that is, when Y2O3 and NH4Cl are mixed and fired, the reactions shown in the following formulas (2) and (3) proceed.

[0058] Y2O3 + 12NH4Cl → 2(NH4)3YCl6 + 6NH3 + 3H2O ···(2) 2(NH4)3YCl6 → 2(NH4) 0.5 YCl 3.5 + 5NH4Cl ···(3)

[0059] When a mixture containing Y2O3 and NH4Cl is calcined at about 200 °C, for example, the reaction represented by formula (2) occurs. As a result, (NH4)3YCl6 is obtained as the main product. When the above mixture is calcined at about 350 °C, for example, the reaction represented by formula (3) occurs. As a result, (NH4) 0.5 YCl 3.5 is obtained as the main product. Thus, when the calcination temperature changes, the value of a can also change.

[0060] In addition, in order for this reaction to proceed smoothly, NH4α may be prepared in excess of Y2O3. For example, NH4α is prepared in an excess of 5 to 15 mol% over Y2O3.

[0061] The calcination may be carried out in an inert gas atmosphere or under reduced pressure.

[0062] (NH4) b Gdβ 3+b is synthesized, for example, as follows.

[0063] As raw materials, Gd2O3 and NH4β are mixed so as to have a Gd2O3:NH4β molar ratio of, for example, 1:12 to obtain a mixture. The mixture is calcined at, for example, 150 °C or higher and 350 °C or lower. The value of b can vary depending on the calcination temperature.

[0064] For example, when β is Cl, that is, when Gd2O3 and NH4Cl are mixed and calcined, the reactions represented by the following formulas (4) and (5) proceed.

[0065] Gd2O3 + 12NH4Cl → 2(NH4)3GdCl6 + 6NH3 + 3H2O ···(4) 2(NH4)3GdCl6 → 2(NH4) 0.5 GdCl 3.5 + 5NH4Cl ···(5)

[0066] When a mixture containing Gd2O3 and NH4Cl is calcined at about 200 °C, for example, the reaction represented by Equation (4) occurs. As a result, (NH4)3GdCl6 is obtained as the main product. When the above mixture is calcined at about 350 °C, for example, the reaction represented by Equation (5) occurs. As a result, 0.5 GdCl 3.5 is obtained as the main product. Thus, when the calcination temperature changes, the value of b can also change.

[0067] Note that in order for this reaction to proceed smoothly, NH4Cl may be prepared in excess of Gd2O3. For example, NH4β is prepared in an amount 5 to 15 mol% in excess of Gd2O3.

[0068] The calcination may be carried out in an inert gas atmosphere or under reduced pressure.

[0069] In the preparation step S1200, at least one selected from the group consisting of (NH4) a Yα 3+a and (NH4) b Gdβ 3+b may have a part of the metal cations substituted by other metal cations. That is, a part of Y and Gd may be substituted by other metal cations. That is, in (NH4) a Yα 3+a a compound in which a part of Y is substituted by other metal cations, or in (NH4) b Gdβ 3+b a compound in which a part of Gd is substituted by other metal cations may be further prepared. The cation substitution rate by other metal cations for Y and Gd may be less than 50 mol%.

[0070] The halide produced by the production method according to the first embodiment can be used as a solid electrolyte material. The solid electrolyte material is, for example, a solid electrolyte material having lithium ion conductivity. The solid electrolyte material is used, for example, in an all-solid-state lithium ion secondary battery.

Examples

[0071] The present disclosure will be described in more detail below.

[0072] The halide produced by the production method of the present disclosure was evaluated as a solid electrolyte material below.

[0073] <Sample 1> (Preparation of solid electrolyte material) First, (NH4)3YCl6 and (NH4)3GdCl6 were synthesized.

[0074] As raw materials for (NH4)3YCl6, Y2O3 and NH4Cl were prepared so that the molar ratio of Y2O3:NH4Cl was 1:13.2. That is, NH4Cl was prepared to be 10 mol% in excess of Y2O3. These materials were ground and mixed in an agate mortar. The obtained mixture was placed in an alumina crucible and fired at 200 °C for 15 hours in a nitrogen atmosphere. Thus, (NH4)3YCl6 was obtained.

[0075] As raw materials for (NH4)3GdCl6, Gd2O3 and NH4Cl were prepared so that the molar ratio of Gd2O3:NH4Cl was 1:13.2. That is, NH4Cl was prepared to be 10 mol% in excess of Gd2O3. These materials were ground and mixed in an agate mortar. The obtained mixture was placed in an alumina crucible and fired at 150 °C for 15 hours in a nitrogen atmosphere. Thus, (NH4)3GdCl6 was obtained.

[0076] Next, in an argon atmosphere having a dew point of -60°C or lower and an oxygen concentration of 0.0001% by volume or lower (hereinafter referred to as "dry argon atmosphere"), (NH4)3YCl6, (NH4)3GdCl6, LiCl, LiBr, and CaBr2 were prepared so that the molar ratio was (NH4)3YCl6:(NH4)3GdCl6:LiCl:LiBr:CaBr2 = 0.6:0.4:0.5:2.3:0.1. These materials were ground and mixed in an agate mortar. The obtained mixture was placed in an alumina crucible and fired at 500°C for 1 hour in a dry argon atmosphere. The obtained fired product was ground in an agate mortar. In this way, a solid electrolyte material composed of Sample 1 containing Li, Ca, Y, Gd, Br, and Cl was obtained.

[0077] (Composition analysis of solid electrolyte material) The contents of Li, Y, Ca, and Gd per unit weight of the solid electrolyte material by Sample 1 were measured by high-frequency inductively coupled plasma optical emission spectrometry using a high-frequency inductively coupled plasma optical emission spectrometer (Thermo Fisher Scientific, iCAP7400). Based on the contents of Li, Ca, Y, and Gd obtained from this measurement result, the Li:Ca:Y:Gd molar ratio was calculated. As a result, the solid electrolyte material by Sample 1 had a Li:Ca:Y:Gd molar ratio of 2.8:0.1:0.6:0.4.

[0078] (Evaluation of ionic conductivity) Figure 4 shows a schematic diagram of the pressure molding die 200 used to evaluate the ionic conductivity of the solid electrolyte material.

[0079] The pressure molding die 200 included a punch upper part 201, a frame type 202, and a punch lower part 203. The frame type 202 was formed of insulating polycarbonate. The punch upper part 201 and the punch lower part 203 were formed of electronically conductive stainless steel.

[0080] Using the pressure forming die 200 shown in Fig. 4, the impedance of the solid electrolyte material by Sample 1 was measured by the following method.

[0081] In a dry argon atmosphere, the powder of the solid electrolyte material by Sample 1 was filled inside the pressure forming die 200. Inside the pressure forming die 200, a pressure of 300 MPa was applied to the solid electrolyte material by Sample 1 using the upper punch 201 and the lower punch 203.

[0082] While the pressure was applied, the upper punch 201 and the lower punch 203 were connected to a potentiostat (Princeton Applied Research, VersaSTAT4) equipped with a frequency response analyzer. The upper punch 201 was connected to the working electrode and the terminal for potential measurement. The lower punch 203 was connected to the counter electrode and the reference electrode. The impedance of the solid electrolyte material was measured at room temperature by the electrochemical impedance measurement method.

[0083] Fig. 5 is a graph showing the Cole-Cole plot obtained by measuring the impedance of the solid electrolyte material by Sample 1.

[0084] In Fig. 5, the real value of the impedance at the measurement point where the absolute value of the phase of the complex impedance is the smallest was regarded as the resistance value for the ion conduction of the solid electrolyte material. For the real value, refer to the arrow R shown in Fig. 5. SE The ionic conductivity was calculated based on the following formula (6) using the resistance value. σ=(R SE ×S / t) -1 ··· (6) Here, σ represents the ionic conductivity. S represents the contact area of the solid electrolyte material with the upper punch 201 (equal to the cross-sectional area of the hollow part of the frame type 202 in Fig. 4). R represents the resistance value of the solid electrolyte material in the impedance measurement. t represents the thickness of the solid electrolyte material (i.e., the thickness of the layer formed from the powder 101 of the solid electrolyte material in Fig. 4).

[0085] The ionic conductivity of the solid electrolyte material by Sample 1, measured at 25 °C, was 3.9×10 -4 S / cm.

[0086] <Sample 2 to 33> (Preparation of solid electrolyte material) For Samples 2 to 20 and 33, a solid electrolyte material by Sample 2 to 20 was obtained in the same manner as Sample 1, except for the firing temperature and firing time. The firing temperature and firing time are shown in Tables 1 and 2.

[0087] For Sample 21, (NH4)3YCl6, (NH4)3GdCl6, LiCl, LiBr, and CaBr2 were prepared as raw material powders so as to have a molar ratio of (NH4)3YCl6:(NH4)3GdCl6:LiCl:LiBr:CaBr2 = 0.4:0.6:0.5:2.3:0.1.

[0088] For Sample 22, (NH4)3YCl6, (NH4)3GdCl6, LiCl, LiBr, and CaBr2 were prepared as raw material powders so as to have a molar ratio of (NH4)3YCl6:(NH4)3GdCl6:LiCl:LiBr:CaBr2 = 0.5:0.5:0.5:2.3:0.1.

[0089] For Sample 23, (NH4)3YCl6, (NH4)3GdCl6, LiCl, LiBr, and CaBr2 were prepared as raw material powders so as to have a molar ratio of (NH4)3YCl6:(NH4)3GdCl6:LiCl:LiBr:CaBr2 = 0.7:0.3:0.5:2.3:0.1.

[0090] For Sample 24, (NH4)3YCl6, (NH4)3GdCl6, LiCl, LiBr, and CaBr2 were prepared as raw material powders so as to have a molar ratio of (NH4)3YCl6:(NH4)3GdCl6:LiCl:LiBr:CaBr2 = 0.9:0.1:0.5:2.3:0.1.

[0091] In Sample 25, (NH4)3YCl6, (NH4)3GdCl6, LiBr, and CaBr2 were prepared as raw material powders so that the molar ratio was (NH4)3YCl6:(NH4)3GdCl6:LiBr:CaBr2 = 0.4:0.6:2.8:0.1.

[0092] In Sample 26, (NH4)3YCl6, (NH4)3GdCl6, LiCl, LiBr, and CaBr2 were prepared as raw material powders so that the molar ratio was (NH4)3YCl6:(NH4)3GdCl6:LiCl:LiBr:CaBr2 = 0.4:0.6:1.0:1.8:0.1.

[0093] Except for the above matters, solid electrolyte materials from Samples 21 to 26 were obtained in the same manner as in Sample 1.

[0094] In Sample 27, first, (NH4) 0.5 GdCl 3.5 was synthesized.

[0095] (NH4) 0.5 GdCl 3.5 As raw materials for, Gd2O3 and NH4Cl were weighed so that the molar ratio was Gd2O3:NH4Cl = 1:13.2. That is, NH4Cl was prepared to be 10 mol% in excess of Gd2O3. These materials were ground and mixed in an agate mortar. The obtained mixture was put into an alumina crucible and fired at 350 °C for 15 hours in a nitrogen atmosphere. In this way, (NH4) 0.5 GdCl 3.5 was obtained.

[0096] Next, in a dry argon atmosphere, as raw material powders, (NH4)3YCl6, (NH4) 0.5 GdCl 3.5 , LiCl, LiBr, and CaBr2, where (NH4)3YCl6:(NH4) 0.5 GdCl 3.5:It was prepared so that the molar ratio was LiCl:LiBr:CaBr2 = 0.6:0.4:0.5:2.3:0.1. Except for the above matters, a solid electrolyte material was obtained with Sample 27 in the same manner as Sample 1.

[0097] In Sample 28, first, GdCl3, which is a raw material of the solid electrolyte material, was synthesized.

[0098] As raw materials for GdCl3, Gd2O3 and NH4Cl were prepared so that the molar ratio was Gd2O3:NH4Cl = 1:13.2. That is, NH4Cl was prepared to be 10 mol% in excess with respect to Gd2O3. These materials were pulverized and mixed in an agate mortar. The obtained mixture was put into an alumina crucible and fired at 450 °C for 15 hours in a nitrogen atmosphere. In this way, GdCl3 was obtained.

[0099] Next, in a dry argon atmosphere, as raw material powders, (NH4)3YCl6, GdCl3, LiCl, LiBr, and CaBr2 were prepared so that the molar ratio was (NH4)3YCl6:GdCl3:LiCl:LiBr:CaBr2 = 0.6:0.4:0.5:2.3:0.1. Except for the above matters, a solid electrolyte material was obtained with Sample 28 in the same manner as Sample 1.

[0100] In Sample 29, first, (NH4) 0.5 YCl 3.5 was synthesized.

[0101] (NH4) 0.5 YCl 3.5 As raw materials for, Y2O3 and NH4Cl were prepared so that the molar ratio was Y2O3:NH4Cl = 1:13.2. That is, NH4Cl was prepared to be 10 mol% in excess with respect to Y2O3. These materials were pulverized and mixed in an agate mortar. The obtained mixture was put into an alumina crucible and fired at 350 °C for 15 hours in a nitrogen atmosphere. In this way, (NH4) 0.5 YCl 3.5 was obtained.

[0102] Next, in a dry argon atmosphere, as raw material powder, (NH4) 0.5 YCl 3.5 , (NH4)3GdCl6, LiCl, LiBr, and CaBr2 were prepared so that the molar ratio was (NH4) 0.5 YCl 3.5 : (NH4)3GdCl6: LiCl: LiBr: CaBr2 = 0.6: 0.4: 0.5: 2.3: 0.1. Except for the above matters, in the same manner as Sample 1, a solid electrolyte material according to Sample 29 was obtained.

[0103] In Sample 30, first, YCl3, which is a raw material of the solid electrolyte material, was synthesized.

[0104] As raw materials for YCl3, Y2O3 and NH4Cl were prepared so that the molar ratio was Y2O3: NH4Cl = 1: 13.2. That is, NH4Cl was prepared to be 10 mol% in excess with respect to Y2O3. These materials were ground and mixed in an agate mortar. The obtained mixture was put into an alumina crucible and fired at 450 °C for 15 hours in a nitrogen atmosphere. Thus, YCl3 was obtained.

[0105] Next, in a dry argon atmosphere, as raw material powder, YCl3, (NH4)3GdCl6, LiCl, LiBr, and CaBr2 were prepared so that the molar ratio was YCl3: (NH4)3GdCl6: LiCl: LiBr: CaBr2 = 0.6: 0.4: 0.5: 2.3: 0.1. Except for the above matters, in the same manner as Sample 1, a solid electrolyte material according to Sample 30 was obtained.

[0106] In Sample 31, first, (NH4)3YBr6, which is a raw material of the solid electrolyte material, was synthesized.

[0107] As raw materials for (NH4)3YBr6, Y2O3 and NH4Br were prepared so as to have a molar ratio of Y2O3:NH4Br = 1:13.2 (that is, NH4Br was prepared to be 10 mol% in excess relative to Y2O3). These materials were pulverized and mixed in an agate mortar. The obtained mixture was placed in an alumina crucible and calcined at 200 °C for 15 hours in a nitrogen atmosphere. In this way, (NH4)3YBr6 was obtained.

[0108] Next, in a dry argon atmosphere, (NH4)3YBr6, (NH4)3GdCl6, LiCl, LiBr, and CaCl2 as raw material powders were prepared so as to have a molar ratio of (NH4)3YBr6:(NH4)3GdCl6:LiCl:LiBr:CaCl2 = 0.6:0.4:0.5:2.3:0.1. Except for the above matters, in the same manner as in Sample 1, a solid electrolyte material according to Sample 31 was obtained.

[0109] In Sample 32, first, (NH4)3GdBr6 serving as a raw material for the solid electrolyte material was synthesized.

[0110] As raw materials for (NH4)3GdBr6, Gd2O3 and NH4Br were prepared so as to have a molar ratio of Gd2O3:NH4Br = 1:13.2 (that is, NH4Br was prepared to be 10 mol% in excess relative to Gd2O3). These materials were pulverized and mixed in an agate mortar. The obtained mixture was placed in an alumina crucible and calcined at 200 °C for 15 hours in a nitrogen atmosphere. In this way, (NH4)3GdBr6 was obtained.

[0111] Next, in a dry argon atmosphere, (NH4)3YCl6, (NH4)3GdBr6, LiCl, LiBr, and CaCl2 as raw material powders were prepared so as to have a molar ratio of (NH4)3YCl6:(NH4)3GdBr6:LiCl:LiBr:CaCl2 = 0.5:0.5:1.0:1.85:0.075. Except for the above matters, in the same manner as in Sample 1, a solid electrolyte material according to Sample 32 was obtained.

[0112] (Evaluation of Ionic Conductivity) The ionic conductivities of the solid electrolyte materials from Samples 2 to 33 were measured in the same manner as Sample 1. The measurement results are shown in Tables 1 and 2.

[0113] In Tables 1 and 2, Raw Material 1 is a halide containing Y. Raw Material 2 is a halide containing Gd. Raw Material 3 is LiCl. Raw Material 4 is LiBr. Raw Material 5 is a halide containing Ca.

[0114] [Table 1]

[0115] [Table 2]

[0116] [Discussion] As is clear from Samples 1 to 33, the obtained solid electrolyte materials have an ionic conductivity of 2.6×10 -10 S / cm or more at room temperature. As is clear when comparing Samples 1 to 32 with Sample 33, if the firing temperature is 300°C or higher and 700°C or lower, the obtained solid electrolyte materials have an even higher ionic conductivity of 7.6×10 -7 S / cm or more at room temperature. This is considered to be because the obtained solid electrolyte materials have high crystallinity.

[0117] As is clear when comparing Samples 1, 5, 8 to 12, and 16 to 20 with Sample 2, if the firing temperature is 350°C or higher and 700°C or lower, the ionic conductivity of the solid electrolyte material becomes higher. As is clear when comparing Samples 1, 8 to 12, and 16 to 20 with Sample 5, if the firing temperature is 400°C or higher and 700°C or lower, the ionic conductivity of the solid electrolyte material becomes even higher. As is clear when comparing Samples 1, 9 to 12, and 16 to 20 with Sample 8, if the firing temperature is 420°C or higher and 700°C or lower, the ionic conductivity of the solid electrolyte material becomes even higher. This is presumably because the solid electrolyte material has higher crystallinity.

[0118] As is clear when comparing Samples 3, 4, 6, and 7 with Samples 2 and 5, when the firing temperature is less than 500°C, if the firing time is 24 hours or more and 60 hours or less, the solid electrolyte material has higher ionic conductivity.

[0119] As described above, the solid electrolyte material produced by the manufacturing method of the present disclosure has high lithium ion conductivity. Furthermore, the manufacturing method of the present disclosure is a simple method and an industrially highly productive method. An industrially highly productive method is, for example, a method that can be mass-produced at low cost.

Industrial Applicability

[0120] The manufacturing method of the present disclosure is used, for example, as a manufacturing method of a solid electrolyte material. The solid electrolyte material produced by the manufacturing method of the present disclosure is used, for example, in all-solid-state lithium ion secondary batteries.

Explanation of Signs

[0121] 101 Powder of solid electrolyte material 200 Pressing die 201 Upper punch 202 Frame type 203 Lower punch

Claims

**Claim 1**: A method for producing a halide, wherein (NH 4 ) a Yα 3+a (NH 4 ) b Gdβ 3+b , Liγ, and Caδ 2 including a firing step of firing a mixed material containing them in an inert gas atmosphere α, β, γ, and δ are each independently at least one selected from the group consisting of Cl and Br, and the following three formulas: 0.5 ≤ a ≤ 3, 0.5 ≤ b ≤ 3, and 1.0 ≤ a + b ≤ 6, are satisfied, when the molar ratios of (NH₄)ₐYα₃₊ₐ, (NH₄)bGdβ₃₊b, Liγ, and Caδ₂ in the mixed material are (NH₄)ₐYα₃₊ₐ : (NH₄)bGdβ₃₊b : Liγ : Caδ₂ = A : B : C : D, 0.4 ≤ A ≤ 0.9, 0.1 ≤ B ≤ 0.6, 2.8 ≤ C ≤ 2.85, and 0.075 ≤ D ≤ 0.1 are satisfied, the produced halide contains at least one selected from the group consisting of Cl and Br, in the firing step, the mixed material is fired at 300 °C or higher and 700 °C or lower for 1 hour or longer and 72 hours or shorter, A method for producing a halide. **Claim 2**: In the firing step, the mixed material is fired at 350 °C or higher, The production method according to claim 1. **Claim 3**: In the firing step, the mixed material is fired at 650 °C or lower, The production method according to claim 1 or 2. **Claim 4**: The following two formulas: a = 3, and b = 3, are satisfied, The production method according to any one of claims 1 to 3. **Claim 5**: The above (NH 4 ) a Yα 3+a and (NH 4 ) b Gdβ 3+b further includes a preparation step of preparing them, In the preparation step, the (NH 4 ), a Yα 3+a is synthesized from Y 2 O 3 and NH 4 α, and the (NH 4 ), b Gdβ 3+b is synthesized from Gd 2 O 3 and NH 4 β. The production method according to any one of claims 1 to 4.

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