Method for producing an oxyhalide

Abstract

The production method according to the present disclosure comprises a baking step for baking a material mixture at 150-450°C. The material mixture contains MX5 and at least one selected from the group consisting of Li2O2, Li2O, and LiOH. M represents at least one element selected from the group consisting of Ta and Nb. X represents at least one element selected from the group consisting of Cl and Br.

Description

Technical Field

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

Background Art

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

Prior Art Documents

Patent Documents

[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 an oxyhalide with high industrial productivity.

Means for Solving the Problems

[0005] The production method of the present disclosure includes a firing step in which a mixed material is fired at 150°C or higher and 450°C or lower, the mixed material including at least one selected from the group consisting of Li2O2, Li2O, and LiOH and MX5, M being at least one selected from the group consisting of Ta and Nb, and X being at least one selected from the group consisting of Cl and Br.

Effects of the Invention

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

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out 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 the 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 at 150°C or higher and 450°C or lower. Here, the firing temperature is the ambient temperature.

[0011] The mixed material fired in the firing step S1000 includes at least one selected from the group consisting of Li2O2, Li2O, and LiOH and MX5. M is at least one selected from the group consisting of Ta and Nb. X is at least one selected from the group consisting of Cl and Br.

[0012] The manufacturing method according to the first embodiment is an industrially highly productive method for producing an oxyhalide. An industrially highly productive method is a method that can be produced in large quantities at low cost. That is, an oxyhalide containing Li (lithium) and Ta (tantalum) or Nb (niobium) can be produced by a simple manufacturing method.

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

[0014] In the firing step S1000, for example, the powder of the mixed material may be placed in an airtight container and fired in a heating furnace. At this time, the state in which the temperature of the mixed material is raised to 150°C or higher and 450°C or lower 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 in the fired product due to, for example, the volatilization of the oxyhalide. The firing time that does not cause a compositional shift in the fired product means the firing time that does not impair the ionic conductivity of the fired product. The airtight container is, for example, a container made of quartz glass or borosilicate glass. The inside of the airtight container may be vacuum, or may be filled with an inert gas or dry air. Examples of the inert gas are helium, nitrogen, or argon. According to the manufacturing method according to the first embodiment, for example, an oxyhalide having an ionic conductivity of 0.14 mS / cm or higher in the vicinity of room temperature can be manufactured.

[0015] In order to manufacture an oxyhalide having a higher ionic conductivity by an industrially highly productive method, in the firing step S1000, the mixed material may be fired at 200°C or higher. For example, it may be fired at 200°C or higher and 450°C or lower. When the firing temperature is 200°C or higher, the oxyhalide as the fired product has higher crystallinity. As a result, the ionic conductivity of the oxyhalide as the fired product can be further increased. That is, a higher-quality oxyhalide solid electrolyte material can be obtained.

[0016] In order to manufacture an oxyhalide having a higher ionic conductivity by an industrially highly productive method, in the firing step S1000, the mixed material may be fired at 400°C or lower. For example, it may be fired at 150°C or higher and 400°C or lower, or at 200°C or higher and 400°C or lower. When the firing temperature is 400°C or lower, decomposition of the oxyhalide can be suppressed. As a result, the ionic conductivity of the oxyhalide as the fired product can be further increased. That is, a higher-quality oxyhalide solid electrolyte material can be obtained.

[0017] In order to produce an oxyhalide having higher ionic conductivity by an industrially highly productive method, in the firing step S1000, the mixed material may be fired at 350 °C or lower. For example, it may be fired at 150 °C or higher and 350 °C or lower, or 200 °C or higher and 350 °C or lower. When the firing temperature is 350 °C or lower, decomposition of the oxyhalide can be suppressed. As a result, the ionic conductivity of the fired oxyhalide can be further increased. That is, a higher quality oxyhalide solid electrolyte material can be obtained.

[0018] In order to produce an oxyhalide having higher ionic conductivity by an industrially highly productive method, in the firing step S1000, the mixed material may be fired for 30 minutes or more and 12 hours or less. When the firing time is 30 minutes or more, the mixed material can react sufficiently. That is, at least one selected from the group consisting of Li2O2, Li2O, and LiOH and MX5 can react sufficiently. When the firing time is 12 hours or less, decomposition of the fired oxyhalide can be suppressed. As a result, the ionic conductivity of the fired oxyhalide can be further increased. That is, a higher quality oxyhalide solid electrolyte material can be obtained.

[0019] In order to produce an oxyhalide having higher ionic conductivity by an industrially highly productive method, in the firing step S1000, the mixed material may be fired for 3 hours or more and 12 hours or less. When the firing time is 3 hours or more, the mixed material can react more sufficiently. That is, at least one selected from the group consisting of Li2O2, Li2O, and LiOH and MX5 can react sufficiently. As a result, the ionic conductivity of the fired oxyhalide can be further increased. That is, a higher quality oxyhalide solid electrolyte material can be obtained.

[0020] After the firing step S1000, the fired product may be pulverized. At this time, a pulverizing device may be used. The pulverizing device is, for example, a mortar or a mixer.

[0021] To enhance the properties of the oxyhalide (e.g., ionic conductivity), the mixed material may contain Li2O2 or LiOH. Desirably, the mixed material may contain Li2O2.

[0022] To enhance the properties of the oxyhalide (e.g., ionic conductivity), the mixed material may further contain NbOCl3.

[0023] To enhance the properties of the oxyhalide (e.g., ionic conductivity), the mixed material may further contain at least one selected from the group consisting of LiF and MeF5. Here, Me is at least one selected from the group consisting of Ta and Nb.

[0024] To enhance the ionic conductivity of the oxyhalide, in the mixed material, the total molar ratio of the raw materials containing Li to MX5 may be 0.4 or more and 1 or less. Also, the molar ratio may be 0.6 or more and 1 or less. Desirably, the molar ratio may be 0.6 or more and 0.8 or less. The raw materials containing Li are, for example, Li2O2, Li2O, LiOH, or LiF.

[0025] To enhance the ionic conductivity of the oxyhalide, X may contain Cl. Desirably, X may be Cl.

[0026] That is, the mixed material fired in the firing step S1000 may contain at least one selected from the group consisting of Li2O2, Li2O, and LiOH, and MCl5.

[0027] In an industrially highly productive method for producing an oxy-chloride, the mixed material fired in the firing step S1000 may be at least one selected from the group consisting of Li2O2, Li2O, and LiOH, and at least one selected from the group consisting of TaCl5 (tantalum chloride) and NbCl5 (niobium chloride). By a simple production method, an oxy-chloride containing Li and at least one selected from the group consisting of Ta and Nb can be produced.

[0028] FIG. 2 is a flowchart showing an example of the production method according to the first embodiment.

[0029] As shown in FIG. 2, the production method according to the first embodiment may further include a mixing step S1100. The mixing step S1100 is executed before the firing step S1000.

[0030] In the mixing step S1100, at least one selected from the group consisting of Li2O2, Li2O, and LiOH, which is a raw material of an oxy-halide, and MX5 are mixed. As a result, a mixed material is obtained. That is, the material to be fired in the firing step S1000 is obtained.

[0031] In the mixing step S1100, at least one selected from the group consisting of Li2O2, Li2O, and LiOH and MX5 may be prepared and mixed so as to have a target molar ratio.

[0032] In the mixing step S1100, Li2O2 and TaCl5 may be mixed. Here, the molar ratio of Li2O2 to TaCl5 may be 0.4 or more and 1.0 or less.

[0033] For mixing the raw materials, known mixing devices may be used. The mixing device is, for example, a mortar, a blender, or a ball mill.

[0034] In the firing step S1000, the powdery mixed material may be fired. The powdery mixed material obtained in the mixing step S1100 may be formed into pellets. In the firing step S1000, the pelletized mixed material may be fired.

[0035] In the mixing step S1100, a mixed material may be obtained by further mixing not only at least one selected from the group consisting of Li2O2, Li2O, and LiOH and MX5, but also another material. For example, a mixed material may be obtained by further mixing at least one selected from the group consisting of NbOCl3, LiF, and MeF5. Here, Me is at least one selected from the group consisting of Ta and Nb.

[0036] In the mixing step S1100, a mixed material may be obtained by mixing a raw material mainly composed of at least one selected from the group consisting of Li2O2, Li2O, and LiOH and a raw material mainly composed of MX5. The main component means the component contained in the largest amount in terms of molar ratio.

[0037] FIG. 3 is a flowchart showing an example of the manufacturing method according to the first embodiment.

[0038] As shown in FIG. 3, the manufacturing method according to the first embodiment may further include a preparation step S1200. The preparation step S1200 is executed before the mixing step S1100.

[0039] In the preparation step S1200, raw materials such as Li2O2, Li2O, LiOH, or MX5 are prepared. That is, the materials to be mixed in the mixing step S1100 are prepared.

[0040] In the preparation step S1200, raw materials such as Li2O2, Li2O, LiOH, or MX5 may be synthesized. The purity of the raw material may be 99% by mass or more. In the preparation step S1200, known commercially available products may be used.

[0041] The raw materials to be prepared may be dried.

[0042] Examples of the shape of the raw materials to be prepared are crystalline, massive, flaky, or powdery. In the preparation step S1200, powdery raw materials may be obtained by pulverizing crystalline, massive, or flaky raw materials.

[0043] In order to enhance the properties (e.g., ionic conductivity) of the oxyhalide, at least one selected from the group consisting of NbOCl3, LiF, and MeF5 may be added in the preparation step S1200. Here, Me is at least one selected from the group consisting of Ta and Nb.

[0044] The oxyhalide produced by the manufacturing method of the present disclosure can be used as a solid electrolyte material. The solid electrolyte material may be, for example, a solid electrolyte with lithium ion conductivity. The solid electrolyte material is used, for example, in all-solid-state lithium ion secondary batteries.

Examples

[0045] Hereinafter, the present disclosure will be described in more detail with reference to examples.

[0046] Hereinafter, the oxyhalide produced by the manufacturing method of the present disclosure was evaluated as a solid electrolyte material.

[0047] <Example 1> (Preparation of solid electrolyte material) In an argon atmosphere (hereinafter referred to as "dry argon atmosphere") having a dew point of -60°C or lower and an oxygen concentration of 0.0001% by volume or lower, Li2O2 and TaCl5 were prepared as raw material powders so that the molar ratio of Li2O2:TaCl5 was 0.8:1. These materials were pulverized and mixed in an agate mortar. The obtained mixture was placed in a quartz glass filled with argon gas and fired at 320°C for 3 hours. The obtained fired product was pulverized in an agate mortar. In this way, the solid electrolyte material according to Example 1 was obtained.

[0048] (Evaluation of ionic conductivity) Figure 4 shows a schematic diagram of the pressure molding die 200 used for evaluating the ionic conductivity of the solid electrolyte material.

[0049] The pressure molding die 200 included a punch upper part 201, a frame mold 202, and a punch lower part 203. The frame mold 202 was formed of insulating polycarbonate. Both the punch upper part 201 and the punch lower part 203 were formed of electronically conductive stainless steel.

[0050] Using the pressure molding die 200 shown in Figure 4, the ionic conductivity of the solid electrolyte material according to Example 1 was measured by the following method.

[0051] In a dry atmosphere having a dew point of -60°C or lower, the solid electrolyte material according to Example 1 was filled inside the pressure molding die 200. Using the punch upper part 201 and the punch lower part 203, a pressure of 300 MPa was applied to the solid electrolyte material according to Example 1 (that is, the powder 101 of the solid electrolyte material in Figure 4).

[0052] With pressure 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 potential measurement terminal. The lower punch 203 was connected to the counter electrode and the reference electrode. The ionic conductivity of the solid electrolyte material was measured at room temperature by the electrochemical impedance measurement method. As a result, the ionic conductivity measured at 24 °C was 6.60 mS / cm.

[0053] <Examples 2 to 18 and Comparative Example 1> (Preparation of Solid Electrolyte Material) In Examples 2 to 9, Li2O2 and TaCl5 were prepared as raw material powders so as to have a molar ratio of Li2O2:TaCl5 = 0.8:1.

[0054] In Example 10, Li2O2 and TaCl5 were prepared as raw material powders so as to have a molar ratio of Li2O2:TaCl5 = 0.6:1.

[0055] In Example 11, Li2O2 and TaCl5 were prepared as raw material powders so as to have a molar ratio of Li2O2:TaCl5 = 0.4:1.

[0056] In Example 12, Li2O2 and TaCl5 were prepared as raw material powders so as to have a molar ratio of Li2O2:TaCl5 = 1:1.

[0057] In Example 13, LiOH and TaCl5 were prepared as raw material powders so as to have a molar ratio of LiOH:TaCl5 = 1:1.

[0058] In Example 14, Li2O and TaCl5 were prepared as raw material powders so as to have a molar ratio of Li2O:TaCl5 = 1:1.

[0059] In Example 15, Li2O2, TaCl5, and NbCl5 were prepared as raw material powders so that the molar ratio was Li2O2:TaCl5:NbCl5 = 0.8:0.5:0.5.

[0060] In Example 16, Li2O2, TaCl5, and NbCl5 were prepared as raw material powders so that the molar ratio was Li2O2:TaCl5:NbCl5 = 0.8:0.3:0.7.

[0061] In Example 17, Li2O2, TaCl5, and NbOCl3 were prepared as raw material powders so that the molar ratio was Li2O2:TaCl5:NbOCl3 = 0.5:0.8:0.2.

[0062] In Example 18, Li2O2, TaCl5, and TaF5 were prepared as raw material powders so that the molar ratio was Li2O2:TaCl5:TaF5 = 0.6:0.9:0.1.

[0063] In Comparative Example 1, Li2O2 and TaCl5 were prepared as raw material powders so that the molar ratio was Li2O2:TaCl5 = 0.8:1.

[0064] Solid electrolyte materials according to Examples 2 to 18 and Comparative Example 1 were obtained in the same manner as in Example 1, except for the above matters, firing temperature, and firing time. The firing temperature and firing time are shown in Table 1.

[0065] (Evaluation of ionic conductivity) The ionic conductivities of the solid electrolyte materials according to Examples 2 to 18 and Comparative Example 1 were measured in the same manner as in Example 1. The measurement results are shown in Table 1.

[0066] [Table 1]

[0067] <Consideration> As is clear from Examples 1 to 18, when the firing temperature is 150°C or higher and 450°C or lower, the obtained oxyhalide has a high ionic conductivity of 0.14 mS / cm or higher near room temperature. On the other hand, as is clear from Comparative Example 1, when the firing temperature is 100°C, the oxyhalide has a low ionic conductivity of 0.067 mS / cm near room temperature. When the firing temperature is 100°C, it is considered that the solid-phase reaction does not proceed sufficiently.

[0068] As is clear from comparing Examples 1 and 3 to 5 with Examples 2, 6, and 7, when the firing temperature is 200°C or higher and 350°C or lower, the oxyhalide has higher ionic conductivity. As is clear from comparing Examples 1, 4, and 5 with Example 3, when the firing temperature is 250°C or higher and 350°C or lower, the ionic conductivity of the oxyhalide becomes even higher. Firing at such a firing temperature is considered to result in the oxyhalide having high crystallinity.

[0069] As is clear from comparing Examples 5 and 9 with Example 8, when the firing time is 3 hours or longer and 12 hours or shorter, the ionic conductivity of the oxyhalide becomes even higher.

[0070] As is clear from comparing Examples 12 and 13 with Example 14, the raw material containing Li results in a higher ionic conductivity of the oxyhalide when it is Li₂O₂ or LiOH rather than Li₂O. As is clear from comparing Example 12 with Example 13, the raw material containing Li results in an even higher ionic conductivity of the oxyhalide when it is Li₂O₂ rather than LiOH.

[0071] As is clear from comparing Examples 5, 10, and 12 with Example 11, when the material to be fired is Li2O2 and TaCl5, if the molar ratio of Li2O2 to TaCl5 is 0.6 or more and 1 or less, the ionic conductivity of the oxyhalide becomes higher. As is clear from comparing Examples 5 and 10 with Example 12, if the molar ratio of Li2O2 to TaCl5 is 0.6 or more and 0.8 or less, the ionic conductivity of the oxyhalide becomes even higher.

[0072] As is clear from comparing Example 15 with Example 16, when the oxyhalide contains Ta and Nb, if the molar ratio of Nb to Ta is greater than 1, the ionic conductivity of the oxyhalide becomes higher.

[0073] As is clear from Example 18, the oxyhalide has high ionic conductivity even when it contains F.

[0074] As described above, the oxyhalide produced by the production method of the present disclosure has high lithium ion conductivity. Furthermore, the production method of the present disclosure is a simple method and an industrially highly productive method.

Industrial Applicability

[0075] The production method of the present disclosure is used, for example, as a production method of a solid electrolyte material. The solid electrolyte material produced by the production method of the present disclosure is used, for example, in an all-solid-state lithium ion secondary battery.

Explanation of Signs

[0076] 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 an oxyhalide, comprising: a firing step in which the mixed material is fired at 150°C or higher and 450°C or lower; The mixed material is Li 2 O 2 、Li 2 O, and at least one selected from the group consisting of LiOH, and MX 5 and includes wherein the oxyhalide to be produced contains Li, M, X, and O, M is at least one selected from the group consisting of Ta and Nb, X is Cl, and satisfies one selected from the group consisting of the following (A) to (C): (A) When the molar ratio of Li₂O₂ to MX₅ is Li₂O₂:MX₅ = α:β, 0.4 ≤ α ≤ 1 and 0.8 ≤ β ≤ 1 are satisfied. (B) The molar ratio of LiOH to MX₅ is 1:

1. (C) The molar ratio of Li₂O to MX₅ is 1:

1. A method for producing an oxyhalide. Claim 2: In the firing step, the mixed material is fired at 200°C or higher. The production method according to claim 1. Claim 3: In the firing step, the mixed material is fired at 400°C or lower. The production method according to any one of claims 1 or 2. Claim 4: In the firing step, the mixed material is fired for 30 minutes or longer and 12 hours or shorter. The production method according to any one of claims 1 to 3. Claim 5: The mixed material further contains NbOCl 3 and The production method according to any one of claims 1 to 4. Claim 6: The mixed material further contains at least one selected from the group consisting of LiF and MeF 5 and Me is at least one selected from the group consisting of Ta and Nb. The production method according to any one of claims 1 to 5.

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