Method for producing halides

Abstract

A method for producing a halide according to the present disclosure comprises baking, in a vacuum or in an inert gas atmosphere, a mixture material containing a powder of MOx and a powder of NH4X. M represents at least one element selected from rare earth elements, X represents at least one element selected from F, Cl, Br, and I, x is 1-2, and, when the average particle diameter of the powder of MOx is defined as D1 and the average particle diameter of the powder of NH4X is defined as D2, requirement (a) or (b) is satisfied.　(a): D1≤D2 and D2-D1≤0.5×D2 (b): D2<D1 and D1-D2≤0.5×D1

Description

[Technical Field]

[0001] The present disclosure relates to a method for producing halides. [Background technology]

[0002] Non-Patent Document 1 discloses solid electrolytes such as Li3YCl6 and Li3YBr6, which are synthesized by firing in a vacuum sealed tube.

[0003] Patent Document 1 discloses a method for synthesizing a halide solid electrolyte by a mechanochemical milling reaction using a planetary ball mill.

[0004] Patent Document 2 discloses a method for producing a halide using an oxide as a raw material. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2018 / 025582 [Patent Document 2] International Publication No. 2020 / 136956 [Non-patent literature]

[0006] [Non-Patent Document 1] Z. Anorg. Allg. Chem., 623(1997), 1352-1356. Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present disclosure is to provide a production method suitable for reducing impurities contained in halides. [Means for solving the problem]

[0008] The present disclosure provides: MO x and NH4X powder, and firing the mixed material in an inert gas atmosphere or in vacuum; M is at least one element selected from rare earth elements, X is at least one element selected from F, Cl, Br, and I; x is greater than or equal to 1 and less than or equal to 2, The MO x When the average particle size of the powder of (I) is defined as D1 and the average particle size of the powder of NH4X is defined as D2, the following requirement (a) or (b) is satisfied: A method for producing a halide is provided. D1≦D2 and D2-D1≦0.5×D2 (a) D2 <D1、かつ、D1-D2≦0.5×D1 ···(b) [Effects of the Invention]

[0009] According to the present disclosure, a manufacturing method suitable for reducing impurities contained in halides can be provided. [Brief explanation of the drawings]

[0010] [Figure 1A] FIG. 1A is a flowchart showing an example of a manufacturing method according to the first embodiment. [Figure 1B] FIG. 1B is a flowchart showing another example of the manufacturing method according to the first embodiment. [Figure 1C] FIG. 1C is a flowchart showing yet another example of the manufacturing method according to the first embodiment. [Figure 1D] FIG. 1D is a flowchart showing yet another example of the manufacturing method according to the first embodiment. [Figure 2A] Figure 2A is an SEM image of the NH4Cl raw material powder before the milling process. [Figure 2B] Figure 2B is an SEM image of the Y2O3 raw material powder. [Figure 2C] Figure 2C is an SEM image of the NH4Cl raw material powder after grinding. [Figure 3] FIG. 3 is a schematic diagram showing a pressure forming die 300 used to evaluate the ionic conductivity of the solid electrolyte. [Figure 4] FIG. 4 is a graph showing a Cole-Cole plot obtained by measuring the impedance of the halide solid electrolyte according to Example 3. DETAILED DESCRIPTION OF THE INVENTION

[0011] (Findings that formed the basis of this disclosure) Non-Patent Document 1 discloses halide solid electrolytes such as Li3YCl6 and Li3YBr6. However, these solid electrolytes are synthesized by sintering in a vacuum sealed tube. The ionic conductivity of the synthesized solid electrolytes is low, and ionic conductivity has not been confirmed at room temperature. Furthermore, sintering in a vacuum sealed tube is not suitable for mass production.

[0012] Patent Document 1 discloses a method for synthesizing a halide solid electrolyte by mechanochemical milling using a planetary ball mill. This method is unsuitable for mass production and has a low yield.

[0013] Patent Document 2 discloses a method for synthesizing a halide solid electrolyte using oxides as raw materials. This method is applicable to mass production, but the raw materials are used in amounts that deviate from the stoichiometric composition in order to ensure sufficient reaction between the raw materials. As a result, raw materials tend to remain, and the ionic conductivity that is inherent to a halide solid electrolyte cannot be obtained.

[0014] In view of the above circumstances, the present inventors have investigated a production method suitable for reducing impurities contained in halides.

[0015] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The following embodiments are merely examples, and the present disclosure is not limited to the following embodiments.

[0016] (First embodiment) FIG. 1A is a flowchart showing an example of a manufacturing method according to the first embodiment.

[0017] The manufacturing method according to the first embodiment includes a first firing step S10.

[0018] In the first firing step S10, MO x The mixed material containing powder of M and powder of NH4X is fired in an inert gas atmosphere or in vacuum. Here, M is at least one element selected from rare earth elements. X is at least one element selected from F, Cl, Br, and I. x is 1 or more and 2 or less.

[0019] MO x When the average particle size of the powder of (I) is defined as D1 and the average particle size of the powder of NH4X is defined as D2, the following requirement (a) or (b) is satisfied. D1≦D2 and D2-D1≦0.5×D2 (a) D2 <D1、かつ、D1-D2≦0.5×D1 ···(b)

[0020] According to the above configuration, the average particle diameters are close to each other, so the materials react easily with each other, which reduces the impurities contained in the target halide. Furthermore, the manufacturing method of the present disclosure employs a so-called calcination method, which is suitable for mass production. However, the calcination method may be used in combination with other synthesis methods such as mechanochemical milling.

[0021] The mixed material is MO x It is obtained by mixing raw material powders such as powder of NH4X and powder of NH4X.

[0022] In the first firing step S10, MO x (i.e., rare earth oxides) react with NH4X (i.e., ammonium halide).

[0023] For example, when M is Y and X is Cl, that is, when Y2O3 reacts with NH4Cl, the reaction shown in the following formula (1) proceeds.

[0024] Y2O3+12NH4Cl→2(NH4)3YCl6+6NH3+3H2O ···(1)

[0025] MO x The average particle size D1 of the powder and the average particle size D2 of the powder of NH4X can be 100 μm or less. x and NH4X react easily. x The lower limit of each of the average particle size D1 of the powder and the average particle size D2 of the NH4X powder is not particularly limited, and the lower limit of each is, for example, 0.05 μm.

[0026] A mixed material is a material that contains two or more MOs with different Ms. x The mixed material may contain two or more types of NH4X having different X's.

[0027] The mixed material is MO x The mixed material may contain materials other than NH4X and NH4X. In this case, all of the materials contained in the mixed material may have average particle sizes similar to each other. For example, the average particle size of the material with the largest average particle size among the materials contained in the mixed material is defined as Dmax, and the average particle size of the material with the smallest average particle size among the materials contained in the mixed material is defined as Dmin. In this case, the difference in average particle size (Dmax - Dmin) may be (0.5 x Dmax) or less. With this configuration, the materials contained in the mixed material are likely to react with each other.

[0028] The mixed material is MO x and NH4X. "MO x and NH4X" means that no other components, except for unavoidable impurities, have been intentionally added.

[0029] To further increase the reactivity of the mixed material, the difference in average particle size (Dmax-Dmin) may be (0.3 x Dmax) or less, or may be (0.1 x Dmax) or less, or may be (0.05 x Dmax) or less.

[0030] All of the materials contained in the mixed material may have an average particle size of 100 μm or less. This configuration allows the materials contained in the mixed material to easily react with each other. The lower limit of the average particle size is, for example, 0.05 μm.

[0031] All of the materials contained in the mixed material may have an average particle size of 50 μm or less. With this configuration, the materials contained in the mixed material are more likely to react with each other.

[0032] MO x The average particle size of materials such as NH4X means the particle size corresponding to 50% cumulative volume in the particle size distribution measured by a laser diffraction / scattering particle size distribution analyzer, i.e., the median diameter (D50).

[0033] The manufacturing method of this embodiment may include a step of pulverizing the materials contained in the mixed material.

[0034] FIG. 1B is a flowchart showing another example of the manufacturing method according to the first embodiment.

[0035] The manufacturing method according to the first embodiment may include a pulverization step S11.

[0036] The materials contained in the mixed material are pulverized before the first firing step S10. That is, the pulverization step S11 is carried out before the first firing step S10.

[0037] In the pulverization step S11, at least one of the materials to be included in the mixed material is pulverized. x , the average particle size of materials such as NH4X can be adjusted.

[0038] For example, assume that the multiple materials to be included in the mixed material include a first material and a second material, and the average particle size of the first material is larger than the average particle size of the second material. In this case, the first material is pre-pulverized to make the average particle size of the first material closer to the average particle size of the second material. Then, the pulverized first material and the second material are mixed to prepare the mixed material. Not only the first material but also the second material may be pulverized. In one example, if the first material is MO x and the second material is NH4X. In another example, the first material is NH4X and the second material is MO x is.

[0039] The pulverization method is not particularly limited, and may be mechanical pulverization. As the pulverization method, a method using a pulverization device such as a ball mill, a pot mill, a speed mill, or a jet mill may be adopted. Pulverization may be performed by a single method or by a combination of multiple methods.

[0040] Solvent-soluble materials can also have their average particle size reduced by dissolution and reprecipitation.

[0041] FIG. 1C is a flowchart showing yet another example of the manufacturing method according to the first embodiment.

[0042] The manufacturing method according to the first embodiment may include a dissolving step S12 and a removing step S13.

[0043] Dissolving the materials contained in the mixed material in a solvent to obtain a solution and removing the solvent from the solution are performed before firing the mixed material, i.e., the dissolving step S12 and the removing step S13 are performed before the first firing step S10.

[0044] In the dissolving step S12, at least one of the materials to be included in the mixed material is dissolved in a solvent. Then, in the removing step S13, the solvent is removed from the solution. x , the average particle size of materials such as NH4X can be adjusted.

[0045] For example, assume that the multiple materials to be included in the mixed material include a first material and a second material, and the average particle size of the first material is larger than the average particle size of the second material. In this case, the first material is dissolved in a solvent to prepare a solution. The solvent is then removed from the solution to re-precipitate the first material. This brings the average particle size of the first material closer to the average particle size of the second material. The first material and the second material are then mixed. The second material may be dissolved and re-precipitated separately from the first material. Alternatively, the dissolving step S12 and the removing step S13 may be performed after all materials to be included in the mixed material are mixed.

[0046] In one example, the first material is NH4X and the second material is MO x In another example, the first material is MO x and the second material is NH4X. In particular, NH4X is an ionic compound and can be sufficiently dissolved in various solvents.

[0047] The solvent may be an inorganic solvent or an organic solvent.

[0048] The dissolving step S12 and the removing step S13 may be performed before the pulverizing step S11, or the dissolving step S12 and the removing step S13 may be performed after the pulverizing step S11.

[0049] The materials with adjusted average particle diameters are precisely weighed and then mixed so as to have a stoichiometric composition in accordance with a chemical reaction formula for obtaining a desired composition.

[0050] To obtain a uniformly mixed material, the manufacturing method of this embodiment may include a mixing step. The mixing method is not limited, and mixing devices such as a ball mill, a pot mill, a V-type mixer, a double-cone mixer, and an automatic mortar can be used.

[0051] In the first firing step S10, the mixed material is fired to obtain a rare earth ammonium halide salt.

[0052] The first baking step S10 is performed in an inert gas atmosphere or in a vacuum. Examples of the inert gas atmosphere include an atmosphere containing helium gas, argon gas, nitrogen gas, or a mixture thereof. When the first baking step S10 is performed in a vacuum, the degree of vacuum is, for example, 10 -1 Pa to 10 -8 It is Pa.

[0053] In the first baking step S10, the baking temperature (ambient temperature) may be 200°C to 250°C.

[0054] In the first firing step S10, the firing time may be from 1 hour to 36 hours.

[0055] The firing temperature and firing time can be appropriately changed depending on the materials used and the type of rare earth ammonium halide salt desired.

[0056] Whether the reaction of the mixed materials is complete, i.e., whether the desired composition has been obtained, can be confirmed by identifying the product phase using an X-ray diffractometer or by measuring the mass change based on the chemical reaction formula. The composition can be identified using methods such as ICP optical emission spectroscopy, ICP mass spectroscopy, and X-ray fluorescence spectroscopy.

[0057] The rare earth ammonium halide salt obtained in the first firing step S10 is reacted with lithium halide to obtain a halide, such as a halide solid electrolyte.

[0058] For example, when a rare earth ammonium halide salt (NH4)3YCl6 reacts with a lithium halide LiBr, the reaction shown in the following formula (2) proceeds.

[0059] (NH4)3YCl6+3LiBr→Li3YBr3Cl3+3NH4Cl ···(2)

[0060] The above reaction yields Li3YBr3Cl3, a compound consisting of lithium, a rare earth element, and a halogen.

[0061] When the average particle size of the rare earth ammonium halide salt powder is defined as D3 and the average particle size of the lithium halide powder is defined as D4, the following requirement (c1) or (d1) may be satisfied. With this configuration, the reaction of formula (2) is likely to proceed. D3≦D4 and D4-D3≦0.5×D4 (c1) D4 <D3、かつ、D3-D4≦0.5×D3 ···(d1)

[0062] To further promote the reaction of formula (2), the following requirement (c2) or (d2) may be satisfied: D3≦D4 and D4-D3≦0.3×D4 (c2) D4 <D3、かつ、D3-D4≦0.3×D3 ···(d2)

[0063] To further promote the reaction of formula (2), the following requirement (c3) or (d3) may be satisfied: D3≦D4 and D4-D3≦0.1×D4 (c3) D4 <D3、かつ、D3-D4≦0.1×D3 ···(d3)

[0064] To further promote the reaction of formula (2), the following requirement (c4) or (d4) may be satisfied: D3≦D4 and D4-D3≦0.05×D4 (c4) D4 <D3、かつ、D3-D4≦0.05×D3 ···(d4)

[0065] The average particle size of each of the rare earth ammonium halide salt and the lithium halide may be 100 μm or less, or may be 50 μm or less. This facilitates the above reaction. The average particle size of each of the rare earth ammonium halide salt and the lithium halide may be 0.05 μm or more.

[0066] The method for adjusting the average particle size of the material, the method for evaluating the average particle size, and the method for mixing the material are as described above.

[0067] The reaction between the rare earth ammonium halide salt obtained in the first calcination step S10 and the lithium halide may be carried out by calcination, for example, the reaction according to formula (2) may be carried out by calcination.

[0068] FIG. 1D is a flowchart showing yet another example of the manufacturing method according to the first embodiment.

[0069] The manufacturing method according to the first embodiment may include a second firing step S20.

[0070] The second baking step S20 is performed before the first baking step S10.

[0071] In the second firing step S20, a material containing a halide and LiZ obtained by firing the mixed material in the first firing step S10 is fired, where Z is at least one element selected from F, Cl, Br, and I.

[0072] The second baking step S20 may be performed in an inert gas atmosphere or in vacuum. Examples of the inert gas atmosphere include an atmosphere containing helium gas, argon gas, nitrogen gas, or a mixture thereof. When the first baking step S10 is performed in vacuum, the degree of vacuum is, for example, 10 -1 Pa to 10 -8 It is Pa.

[0073] In the second firing step S20, the firing temperature (atmospheric temperature) may be 400°C to 700°C.

[0074] In the second firing step S20, the firing time may be from 1 hour to 36 hours.

[0075] The firing temperature and firing time can be appropriately changed depending on the materials used and the type of desired halide.

[0076] Whether the firing reaction is complete or not can be confirmed in the same manner as in the first firing step.

[0077] The reaction of a rare earth ammonium halide salt with a lithium halide provides a compound containing lithium, a rare earth element, and a halogen. This compound can be a solid electrolyte. Specifically, this compound can be a halide solid electrolyte.

[0078] The average particle size of the halide solid electrolyte may be 100 μm or less, preferably 10 μm or less, and more preferably 1 μm or less. The lower limit of the average particle size of the halide solid electrolyte is not particularly limited. The lower limit is, for example, 0.05 μm. The pulverization method for achieving such an average particle size is not limited. As the pulverization method, a method using a pulverizer such as a ball mill, a pot mill, a speed mill, or a jet mill can be used. Pulverization may be performed by a single method or by a combination of multiple methods. [Example]

[0079] The present disclosure will now be described in more detail with reference to examples and comparative examples, in which the halides produced by the methods of the present disclosure are produced and evaluated as solid electrolytes.

[0080] Example 1 (Preparation of (NH4)3YCl6) (NH4)3YCl6 was synthesized as a raw material for the halide solid electrolyte.

[0081] First, commercially available Y2O3 and NH4Cl were prepared as raw material powders.

[0082] Figure 2A is an SEM image of the NH4Cl raw material powder before milling. Figure 2B is an SEM image of the Y2O3 raw material powder. As shown in Figures 2A and 2B, the average particle sizes of the NH4Cl and Y2O3 raw material powders were 1 mm and 0.5 μm, respectively.

[0083] In order to keep the difference in average particle size within 50%, that is, to satisfy the requirement (a) or (b) described above, the NH4Cl raw material powder was pulverized using a hammer mill.

[0084] Figure 2C is an SEM image of the NH4Cl raw powder after grinding. The average particle size of the ground NH4Cl raw powder was 0.8 μm. Therefore, the difference between the average particle size of the NH4Cl raw powder and the average particle size of the Y2O3 raw powder was 0.3 μm. This value was within 50% of the average particle size of the NH4Cl raw powder.

[0085] The Y2O3 raw material powder and the crushed NH4Cl raw material powder were weighed to a molar ratio of Y2O3:NH4Cl = 1:12. These raw material powders were dry mixed using a tumbler mixer. In this way, a mixed material was obtained. The obtained mixed material was placed in an alumina crucible and kept at 200 °C for 15 hours in a nitrogen atmosphere. In this way, (NH4)3YCl6 according to Example 1 was obtained. The mass of (NH4)3YCl6 obtained by firing was divided by the total mass of the mixed material measured before firing to calculate the mass loss rate.

[0086] <Example 2> (Preparation of (NH4)3YCl6) (NH4)3YCl6 of Example 2 was obtained in the same manner as in Example 1 except for the molar ratio of the raw material powders contained in the mixed material.

[0087] In Example 2, the Y2O3 raw material powder and the ground NH4Cl raw material powder were weighed to a molar ratio of Y2O3:NH4Cl = 1:12.6. These raw material powders were dry mixed using a tumbler mixer. In this way, a mixed material was obtained. The molar ratio of Y2O3:NH4Cl = 1:12.6 is a molar ratio in which NH4Cl is 5% in excess of the stoichiometric ratio.

[0088] In Example 2, the mass reduction rate was calculated in the same manner as in Example 1.

[0089] Example 3 (Preparation of halide solid electrolytes) A halide solid electrolyte was synthesized using (NH4)3YCl6 according to Example 1.

[0090] In an argon atmosphere having a dew point of -60°C or less, (NH4)3YCl6 and LiBr from Example 1 were prepared in a molar ratio of (NH4)3YCl6:LiBr = 1:3. These materials were mixed using a tumbler mixer. The resulting mixed material was placed in an alumina crucible. Two crucibles filled with the mixed material were prepared and maintained at 500°C for 1 hour in an electric furnace filled with an argon atmosphere. The two crucibles were placed in positions 1 and 2, respectively, in the electric furnace.

[0091] To confirm reproducibility, the above-described firing was carried out four times. In Table 2, the nth firing is indicated as "Firing n."

[0092] The obtained fired product was pulverized in an agate mortar, and thus a halide solid electrolyte according to Example 3 was obtained.

[0093] The Li content per unit mass of the halide solid electrolyte of Example 3 was measured by atomic absorption spectrometry. The Y content of the halide solid electrolyte of Example 3 was measured by ICP atomic emission spectrometry. Based on the Li and Y contents obtained by these measurements, the Li:Y molar ratio was calculated. As a result, the Li:Y molar ratio was 3:1. This value was consistent with the value calculated from the charging ratio of the raw material powders.

[0094] (Evaluation of ionic conductivity) FIG. 3 is a schematic diagram showing a pressure forming die 200 used to evaluate the ionic conductivity of the solid electrolyte.

[0095] The pressure molding die 200 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.

[0096] The ionic conductivity of the halide solid electrolyte of Example 3 was measured by the following method using the pressure molding die 300 shown in FIG.

[0097] In a dry atmosphere having a dew point of −60° C. or less, the halide solid electrolyte powder according to Example 3 (i.e., solid electrolyte powder 101 in FIG. 3 ) was filled into a pressure molding die 200. A pressure of 400 MPa was applied to the halide solid electrolyte powder 101 according to Example 3 using upper punch 301 and lower punch 303.

[0098] 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 was measured by electrochemical impedance measurement at room temperature.

[0099] FIG. 4 is a graph showing a Cole-Cole plot obtained by measuring the impedance of the halide solid electrolyte according to Example 3.

[0100] In Fig. 4, 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 ion conduction in the halide solid electrolyte. SE Using the resistance value, the ionic conductivity was calculated based on the following formula (3).

[0101] σ=(RSE ×S / t) -1 ···(3)

[0102] Here, σ represents ionic conductivity. S represents the contact area of ​​the solid electrolyte with the punch upper portion 301. S is equal to the cross-sectional area of ​​the hollow portion of the frame mold 302 in FIG. 3. R SE represents the resistance value of the solid electrolyte in impedance measurement. t represents the thickness of the solid electrolyte. t represents the thickness of the layer formed from the solid electrolyte powder 101 in FIG.

[0103] <Comparative Example 1> (Preparation of (NH4)3YCl6) In Comparative Example 1, the NH4Cl raw material powder was not subjected to a pulverization treatment. Other than this, (NH4)3YCl6 according to Comparative Example 1 was obtained in the same manner as in Example 1.

[0104] In Comparative Example 1, the mass reduction rate was calculated in the same manner as in Example 1.

[0105] <Comparative Example 2> (Preparation of (NH4)3YCl6) In Comparative Example 2, the NH4Cl raw material powder was not subjected to a pulverization treatment. Other than this, (NH4)3YCl6 according to Comparative Example 2 was obtained in the same manner as in Example 2.

[0106] In Comparative Example 2, the mass reduction rate was calculated in the same manner as in Example 1.

[0107] <Comparative Example 3> (Preparation of halide solid electrolytes) A halide solid electrolyte according to Comparative Example 3 was prepared in the same manner as in Example 3, except that (NH)YCl according to Comparative Example 1 was used instead of (NH)YCl according to Example 1. A mixed material containing (NH)YCl and LiBr was placed in two alumina crucibles. The two crucibles were placed adjacent to the two alumina crucibles placed in the electric furnace in Example 3. In this manner, the mixed material was fired.

[0108] (Evaluation of ionic conductivity) In the same manner as in Example 3, the ionic conductivity of the halide solid electrolyte of Comparative Example 3 was measured.

[0109] The mass reduction rates in Example 1, Example 2, Comparative Example 1 and Comparative Example 2 are shown in Table 1.

[0110] [Table 1]

[0111] <Consideration> As is clear from Table 1, by pre-pulverizing the NH4Cl raw material powder to reduce the difference in average particle size between the NH4Cl raw material powder and the Y2O3 raw material powder, the mass change rate nearly matched the theoretical value. In other words, impurities were successfully reduced.

[0112] The theoretical value of the mass change rate was calculated based on the following chemical reaction formula: NH3 and H2O correspond to the masses lost.

[0113] Y2O3+12NH4Cl+xNH4Cl → 2(NH4)3YCl6 + xNH4Cl + 6NH3 + 3H2O (x: excess NH4Cl)

[0114] On the other hand, in Comparative Examples 1 and 2, in which no prior crushing treatment was carried out, it is presumed that the reaction did not proceed sufficiently, and therefore some of the raw materials remained.

[0115] The ionic conductivities of the solid electrolytes according to Example 3 and Comparative Example 3 are shown in Table 2.

[0116] [Table 2]

[0117] <Consideration> As is clear from Table 2, the halide solid electrolyte of Example 3 had higher ionic conductivity than the halide solid electrolyte of Comparative Example 3. Furthermore, this result was independent of the firing location. It is presumed that the comparative example had low ionic conductivity due to the influence of unreacted materials remaining in the raw material (NH4)3YCl6. The halide solid electrolyte of the Example contained few impurities, and exhibited the inherent ionic conductivity of the halide solid electrolyte.

[0118] The above results demonstrate that the solid electrolyte synthesized by the production method of the present disclosure exhibits high lithium ion conductivity.

[0119] In addition, MO x It is expected that the same effects as in Examples 1 to 3 will be obtained when M in is a rare earth element other than Y, when X in NH4X is a halogen element other than Cl, or when Z in LiZ is a halogen element other than Cl. This is because compounds composed of elements of the same group generally have similar physical properties, and the same effects can be expected even if the element type is changed. In fact, it was confirmed that the desired compound can be obtained even when NH4Br is used. [Industrial Applicability]

[0120] The manufacturing method of the present disclosure can be used, for example, as a method for manufacturing a solid electrolyte. Furthermore, the solid electrolyte manufactured by the manufacturing method of the present disclosure can be used, for example, in a battery (e.g., an all-solid-state secondary battery). [Explanation of symbols]

[0121] 101 Solid electrolyte powder 300 pressure forming die 301 Punch top 302 Frame type 303 Punch bottom

Claims

1. MO x powder and NH 4 and a powder of X, and firing the mixed material in an inert gas atmosphere or in vacuum; M is at least one element selected from rare earth elements, X is at least one element selected from F, Cl, Br, and I; x is greater than or equal to 1 and less than or equal to 2; The MO x The average particle size of the powder is defined as D1, and the NH 4 When the average particle size of the powder of X is defined as D2, the following requirement (a) or (b) is satisfied: D1≦D2, and D2−D1≦0.5×D2 (a) D2<D1, and D1-D2≦0.5×D1 (b) the difference between the average particle size D1 of the MO x powder and the average particle size D2 of the NH 4 X powder is 0.3 μm or less; Methods for producing halides.

2. The MO x The average particle size D1 of the powder and the NH 4 The average particle size D2 of the powder X is 100 μm or less. The method of claim 1.

3. further comprising grinding at least one material of a plurality of materials to be included in the mixed material; The grinding of the at least one material is performed prior to providing the mixed material and firing the mixed material. The method according to claim 1 or 2.

4. dissolving at least one material among the plurality of materials to be contained in the mixed material in a solvent to obtain a solution; removing the solvent from the solution; further comprising obtaining the solution and removing the solvent are performed prior to firing the mixed material; The method according to claim 1 or 2.

5. The method further comprises calcining a material containing a halide and LiZ obtained by calcining the mixed material; Z is at least one element selected from F, Cl, Br, and I; The method of any one of claims 1 to 4.

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