Material for producing metal ion-containing non-aqueous solvent and method for producing metal ion-containing non-aqueous solvent

Abstract

To provide a material for producing a nonaqueous solvent containing a metal ion and a method for producing the nonaqueous solvent containing a metal ion, in which the nonaqueous solvent containing a metal ion having reduced water content can be produced while suppressing the contamination of a residual cation such as a sodium ion.SOLUTION: A material for producing a nonaqueous solvent containing a metal ion comprises zeolite in which cations corresponding to 88 eq% or more of all the ion-exchangeable cations are ion-exchanged by calcium ions. A method for producing a nonaqueous solvent containing a metal ion brings the material for producing nonaqueous solvent containing a metal ion that comprises zeolite in which cations corresponding to 88 eq% or more of all the ion-exchangeable cations are ion-exchanged by calcium ions, into contact with something having the nonaqueous solvent containing a metal ion.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a material for producing a metal ion-containing nonaqueous solvent and a method for producing a metal ion-containing nonaqueous solvent. [Background technology]

[0002] In lithium ion batteries, a non-aqueous electrolyte solution in which a lithium-based electrolyte such as lithium hexafluorophosphate (LiPF6) is dissolved in an organic non-aqueous solvent is used as the electrolyte solution.

[0003] However, trace amounts of water remain in the solvent and lithium-based electrolyte constituting the electrolytic solution. This water reacts with the lithium-based electrolyte such as LiPF6 to produce hydrogen fluoride (HF) and the like, for example, as shown in the following reaction formulas (1) to (3). TIFF0007644654000001.tif28153

[0004] If acidic impurities such as hydrogen fluoride (hydrofluoric acid) are present in the non-aqueous electrolyte, they can reduce the battery capacity and charge / discharge cycle characteristics of the lithium-ion battery and can make the battery more susceptible to corrosion. This has led to a demand for reducing the amount of water in the non-aqueous electrolyte, and with the improvement in the performance of lithium-ion batteries, there is currently a demand for the water content in the non-aqueous electrolyte to be less than 5 ppm by mass.

[0005] As a method for reducing the water content in a non-aqueous electrolyte solution, a method in which water is adsorbed and removed from the non-aqueous electrolyte solution using zeolite is known. However, when a non-aqueous electrolyte solution is treated with zeolite, sodium ions and the like in the zeolite are eluted into the non-aqueous electrolyte solution as impurities. Therefore, a method is required for reducing the water content in the non-aqueous electrolyte solution while suppressing the sodium ion concentration to, for example, less than 2 ppm by mass, preferably less than 1 ppm by mass.

[0006] For this reason, for example, a method has been proposed in which moisture in a non-aqueous electrolyte solution is removed using zeolite in which 97.5 mol % to 99.5 mol % of exchangeable cations have been exchanged with lithium ions (see Patent Document 1 (JP 2011-71111 A)). According to this method, most of the cations in the zeolite have been exchanged with lithium ions in advance, and it is believed that this method makes it possible to remove moisture from the non-aqueous electrolyte solution while suppressing the incorporation of sodium ions into the non-aqueous electrolyte solution. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2011-71111 A DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0008] However, the inventors of the present invention have found through their investigations that in the method described in Patent Document 1, residual cations such as ion-exchangeable sodium ions, which are present in zeolite in small amounts, are mixed into the non-aqueous electrolyte solution, and further improvements are required.

[0009] Under these circumstances, an object of the present invention is to provide a material for producing a metal ion-containing nonaqueous solvent that can produce a metal ion-containing nonaqueous solvent having a reduced water content while suppressing the inclusion of residual cations such as sodium ions, and a method for producing a metal ion-containing nonaqueous solvent. [Means for solving the problem]

[0010] As a result of intensive research into achieving the above-mentioned object, the present inventors have found that the above-mentioned technical problems can be solved by using a material for producing a metal ion-containing nonaqueous solvent comprising zeolite in which cations equivalent to 88 eq% or more of all ion-exchangeable cations have been ion-exchanged with calcium ions, and have completed the present invention based on this finding.

[0011] That is, the present invention provides (1) A material for producing a metal ion-containing nonaqueous solvent, comprising a zeolite in which cations corresponding to 88 eq.% or more of all ion-exchangeable cations are ion-exchanged with calcium ions; (2) A method for producing a metal ion-containing nonaqueous solvent, comprising contacting a liquid to be treated containing the metal ion-containing nonaqueous solvent with a material for producing a metal ion-containing nonaqueous solvent, the material being made of zeolite in which cations corresponding to 88 eq% or more of all ion-exchangeable cations have been ion-exchanged with calcium ions; (3) The method for producing a non-aqueous solvent containing metal ions according to the above (2), wherein the non-aqueous solvent containing metal ions is a non-aqueous electrolyte solution in which 0.01 eq / L or more of a metal salt electrolyte is dissolved in the non-aqueous solvent. (4) The method for producing a metal ion-containing nonaqueous solvent according to the above (2) or (3), in which a liquid to be treated containing the metal ion-containing nonaqueous solvent is passed through a material for producing the metal ion-containing nonaqueous solvent comprising the zeolite in an upward flow manner. This provides: Effect of the Invention

[0012] According to the present invention, it is possible to provide a material for producing a metal ion-containing nonaqueous solvent, which can produce a metal ion-containing nonaqueous solvent having a reduced water content while suppressing the inclusion of residual cations such as sodium ions, and a method for producing a metal ion-containing nonaqueous solvent. [Brief description of the drawings]

[0013] [Figure 1] 1 is a schematic diagram showing an embodiment of a method for producing a metal ion-containing nonaqueous solvent according to the present invention. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The material for producing a metal ion-containing nonaqueous solvent according to the present invention will be described below. The material for producing a metal ion-containing nonaqueous solvent according to the present invention is characterized in that it comprises a zeolite in which cations equivalent to 88 eq% or more of all ion-exchangeable cations have been ion-exchanged with calcium ions.

[0015] The zeolite constituting the metal ion-containing nonaqueous solvent manufacturing material of the present invention is one in which cations equivalent to 88 eq% or more of all ion-exchangeable cations have been ion-exchanged with calcium ions, preferably one in which cations equivalent to 91 eq% or more of all ion-exchangeable cations have been ion-exchanged with calcium ions, and more preferably one in which cations equivalent to 94 eq% or more of all ion-exchangeable cations have been ion-exchanged with calcium ions. In the above zeolite, there is no particular upper limit to the amount of calcium ions that are ion-exchanged. Generally, however, it is appropriate that an amount equivalent to 100 eq% or less of all ion-exchangeable cations is ion-exchanged with calcium ions, more appropriate that an amount equivalent to 99.8 eq% or less of all ion-exchangeable cations is ion-exchanged with calcium ions, and even more appropriate that an amount equivalent to 99.5 eq% or less of all ion-exchangeable cations is ion-exchanged with calcium ions.

[0016] The metal ion-containing nonaqueous solvent manufacturing material of the present invention is composed of zeolite in which cations equivalent to 88 eq% or more of all ion-exchangeable cations are ion-exchanged with calcium ions, and therefore, when contacted with a liquid to be treated that contains a metal ion-containing nonaqueous solvent, the water content can be suitably reduced while suppressing the elution and contamination of residual cations such as not only calcium ions but also sodium ions.

[0017] In the present application, the ratio of ion-exchanged calcium ions is expressed as a ratio when the molar equivalent of all ion-exchangeable cations in the zeolite is taken as 100 eq %. That is, in the present application, the ratio of ion-exchanged calcium ions means the ratio of the molar equivalents (eq) of calcium ions in the zeolite to the total molar equivalents (eq) of all ion-exchangeable cations in the zeolite, as shown in the following formula (I).

[0018] Percentage of ion-exchanged calcium ions (eq%) = {molar equivalent of calcium ions in zeolite (eq) / total molar equivalent of all ion-exchangeable cations in zeolite (eq)} x 100 (I)

[0019] In the above formula (I), the sum (eq) of the molar equivalents of all ion-exchangeable cations in the zeolite means the sum (eq) of the molar equivalents of calcium ions and sodium ions measured by the method for quantifying cationic species in a zeolite described below. In addition, in the above formula (I), the molar equivalent (eq) of calcium ions in the zeolite means the molar equivalent (eq) of calcium ions measured by the method for quantifying cationic species in the zeolite described below. <Quantitative method for determining cationic species in zeolite> 0.1 g of zeolite is dissolved by heating with 5 ml of 47% hydrofluoric acid and 20 ml of 60% nitric acid, and then 1N nitric acid is added to make a 50 ml solution. The concentration of each cationic species in this solution is measured using an inductively coupled plasma (ICP) emission spectrometer (PerkinElmer OPTIMA3000DV), and the molar equivalent (eq) is calculated from the content of each cationic species in the zeolite.

[0020] In this application, the ratio of calcium ions to the ion-exchangeable cations in the zeolite, calculated by the above formula (I), will be referred to as the "calcium ion exchange rate" as appropriate.

[0021] In the zeolite ion-exchanged with calcium ions, the cations remaining in the zeolite are not particularly limited, and may be one or more selected from alkali metal cations such as sodium ions, lithium ions, and potassium ions; alkaline earth metal cations such as beryllium ions, magnesium ions, and strontium ions; and protons. Generally, most zeolites are synthesized using sodium hydroxide, and therefore most of the cations exchanged with calcium ions and those remaining in the zeolite are usually sodium ions.

[0022] The metal ion-containing nonaqueous solvent manufacturing material of the present invention is made of zeolite having a calcium ion exchange rate of 88 eq% or more, and therefore when contacted with a liquid to be treated that contains a metal ion-containing nonaqueous solvent, not only can it remove a high proportion of water from the liquid to be treated while suppressing the elution of remaining cations such as sodium from the zeolite, but it can also remove some of the free acids.

[0023] The free acid is not particularly limited, but examples thereof include acids such as hydrogen fluoride that are generated by decomposition of the electrolyte in the nonaqueous electrolyte when the nonaqueous electrolyte is treated as a metal ion-containing nonaqueous solvent.

[0024] The zeolite constituting the material for producing a metal ion-containing nonaqueous solvent according to the present invention is preferably at least one zeolite having a crystal type selected from the group consisting of A-type, chabazite, ferrierite, ZSM-5 and clinoptilolite, and more preferably A-type zeolite. Although it is not clear why these zeolites are particularly suitable for treating non-aqueous solvents containing metal ions, it is believed that this is because these zeolites have small pore diameters of approximately 6 Å or less, and among these, type A zeolites have an eight-membered ring pore structure and a smaller pore diameter of 5 Å, and when a non-aqueous electrolyte is treated as a non-aqueous solvent containing metal ions, the non-aqueous solvent of the non-aqueous electrolyte that is solvated with lithium ions does not enter the zeolite pores, making it difficult for the non-aqueous solvent to undergo chemical changes.

[0025] The zeolite constituting the material for producing a metal ion-containing nonaqueous solvent according to the present invention may be in any form such as a powder or a molded body, and is preferably in the form of a molded body which is easy to handle.

[0026] When the zeolite constituting the material for producing a metal ion-containing nonaqueous solvent according to the present invention is in the form of a molded body, such a molded body is preferably one obtained by adding a binder to zeolite and molding it.

[0027] The binder used in the molding may be one or more selected from silica, alumina, clay, etc., and preferably has a low sodium content. Examples of such binders include one or more selected from clays such as kaolin, bentonite, talc, bilophyllite, molysite, verculolite, montmorillonite, chlorite, and halloysite.

[0028] The amount of binder in the molded body is not particularly limited, but in order to obtain excellent processability, it is preferably 10 parts by weight or more and 50 parts by weight or less per 100 parts by weight of powdered zeolite (hereinafter, zeolite powder).

[0029] When zeolite is molded using a binder, it is preferable to convert the binder in the molded body to zeolite (binderless) by immersion in an alkali. By making the molded body binderless, the content of zeolite in the zeolite molded body can be increased, and ultimately, the entire zeolite molded body can be made of zeolite.

[0030] In the molded body in which the binder is partially or entirely rendered binderless, the zeolite content in the molded body is preferably 95% by mass or more, and more preferably 100% by mass. A high zeolite content in the molded body can easily improve the dehydration efficiency of the liquid to be treated, which contains a metal ion-containing nonaqueous solvent.

[0031] The shape of the zeolite molded body is not particularly limited, and may be one or more selected from a spherical, cylindrical, trefoil, elliptical, hollow, etc. The size of the molded body is also not particularly limited, and examples thereof include a spherical or cylindrical body having a diameter of about 0.1 mm to 5 mm.

[0032] There are no particular limitations on the method for preparing the zeolite constituting the material for producing a metal ion-containing nonaqueous solvent according to the present invention, in which cations equivalent to 88 eq% or more of all ion-exchangeable cations are ion-exchanged with calcium ions.

[0033] The method for efficiently exchanging ion-exchangeable cations in zeolite with calcium ions is not particularly limited, but may be, for example, a flow-type ion exchange method in which an aqueous calcium ion solution is passed through zeolite, and cations such as sodium ions in the zeolite are ion-exchanged with calcium ions in the aqueous solution and continuously discharged outside the system. In order to make the calcium ion exchange rate of the entire zeolite uniform, it is preferable to perform the ion exchange treatment while circulating the aqueous calcium ion solution.

[0034] The calcium ion concentration in the aqueous calcium ion solution is not particularly limited, but is preferably 0.1 mol / L or more.

[0035] It is preferable that the zeolite ion-exchanged with calcium ions, which constitutes the material for producing a metal ion-containing nonaqueous solvent according to the present invention, has moisture removed in advance (the zeolite is dehydrated) before contacting the liquid to be treated, which contains the metal ion-containing nonaqueous solvent. The method of dehydrating zeolite is not particularly limited as long as the method and conditions are such that moisture can be removed from the zeolite. Considering the heat resistance of the zeolite itself, it is preferable to remove moisture at as low a temperature as possible, and it is preferable to perform a heat treatment at a temperature of 600°C or less for about 1 to 20 hours in a dry or reduced pressure atmosphere.

[0036] Next, examples of the use of the material for producing a metal ion-containing nonaqueous solvent according to the present invention will be described. Zeolite ion-exchanged with calcium ions (including a molded body of such zeolite), which constitutes the material for producing a metal ion-containing nonaqueous solvent according to the present invention, can be brought into contact with a liquid to be treated that contains a metal ion-containing nonaqueous solvent, as described below, to be highly dehydrated, and a metal ion-containing nonaqueous solvent from which free acids have been sufficiently removed can be easily produced.

[0037] Furthermore, by disposing the zeolite (including a molded body of such zeolite) ion-exchanged with calcium ions, which constitutes the material for producing a metal ion-containing nonaqueous solvent according to the present invention, in, for example, a lithium ion battery, it is possible to adsorb and remove not only moisture mixed in the nonaqueous electrolyte, but also moisture attached to the positive electrode, negative electrode, or separator. In this case, the above-mentioned zeolite can be dispersed in the nonaqueous electrolyte that constitutes the lithium ion battery, or used as a constituent material or an attachment component of the positive electrode, negative electrode, or separator that constitutes the lithium ion battery, thereby making it possible to remove moisture from within the battery.

[0038] According to the present invention, it is possible to provide a material for producing a metal ion-containing nonaqueous solvent that can produce a metal ion-containing nonaqueous solvent having a reduced water content while suppressing the inclusion of residual cations such as sodium ions.

[0039] Next, the method for producing the metal ion-containing nonaqueous solvent according to the present invention will be described. The method for producing a metal ion-containing non-aqueous solvent according to the present invention is characterized in that it comprises contacting a liquid to be treated, which contains a metal ion-containing non-aqueous solvent, with a material for producing a metal ion-containing non-aqueous solvent comprising zeolite in which cations corresponding to 88 eq% or more of all ion-exchangeable cations have been ion-exchanged with calcium ions.

[0040] The zeolite constituting the material for producing a metal ion-containing nonaqueous solvent used in the method for producing a metal ion-containing nonaqueous solvent according to the present invention is as described in detail in the description of the material for producing a metal ion-containing nonaqueous solvent according to the present invention.

[0041] In the method for producing a metal ion-containing nonaqueous solvent according to the present invention, the metal ion-containing nonaqueous solvent is not particularly limited, but is preferably a nonaqueous electrolyte solution in which an electrolyte containing metal ions is dissolved in a nonaqueous solvent.

[0042] The nonaqueous solvent constituting the nonaqueous electrolyte is preferably an organic nonaqueous solvent. Examples of the organic non-aqueous solvent include one or more selected from ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, fluoroethylene carbonate, vinylene carbonate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, γ-butyrolactone, sulfolanes such as sulfolane and dimethyl sulfoxide, 1,2-dimethoxyethane, 1,2-diethoxyethane, 1,2-dibutoxyethane, ethoxymethoxyethane, and the like.

[0043] An example of the electrolyte containing metal ions that constitutes the non-aqueous electrolyte solution is an alkali metal salt electrolyte. The alkali metal salt electrolyte may be a lithium-based electrolyte, and the lithium-based electrolyte may be one or more selected from LiPF6, LiClO4, LiBF4, LiAsF6, LiSbF6, LiAlCl4, LiCF3SO3, LiN(SO2F)2, LiN(SO2CF3)2, etc., and LiPF6 is preferred in terms of battery performance. In the method for producing a non-aqueous electrolyte according to the present invention, the non-aqueous electrolyte is preferably an electrolyte for lithium ion batteries.

[0044] In the method for producing a metal ion-containing nonaqueous solvent according to the present invention, the metal ion-containing nonaqueous solvent (liquid to be treated) is preferably a nonaqueous electrolyte solution in which 0.01 eq / L or more of a metal salt electrolyte is dissolved in the nonaqueous solvent, more preferably a nonaqueous electrolyte solution in which 0.05 to 5.0 eq / L of a metal salt electrolyte is dissolved in the nonaqueous solvent, and even more preferably a nonaqueous electrolyte solution in which 0.2 to 2.0 eq / L of a metal salt electrolyte is dissolved in the nonaqueous solvent.

[0045] In the method for producing a metal ion-containing nonaqueous solvent according to the present invention, when the nonaqueous electrolyte in the metal ion-containing nonaqueous solvent (liquid to be treated) contains a lithium-based electrolyte, the concentration of the lithium-based electrolyte in the liquid to be treated is preferably 0.01 to 10.0 mol / L, more preferably 0.05 to 5.0 mol / L, and even more preferably 0.2 to 2.0 mol / L.

[0046] In this application, the concentration of an alkali metal salt electrolyte such as a lithium-based electrolyte in a metal ion-containing non-aqueous solvent (liquid to be treated) means a value determined from the lithium metal concentration measured by atomic absorption spectrometry using an atomic absorption spectrometer (polarized Zeeman atomic absorption spectrometer ZA3000, manufactured by Hitachi High-Tech Science Corporation).

[0047] In the method for producing a metal ion-containing nonaqueous solvent according to the present invention, the method for contacting a metal ion-containing nonaqueous solvent producing material made of zeolite ion-exchanged with calcium ions with a liquid to be treated that contains a metal ion-containing nonaqueous solvent is not particularly limited. Examples of the method include a method in which a liquid to be treated containing a metal ion-containing non-aqueous solvent is passed through a column or tank packed with a material for producing a metal ion-containing non-aqueous solvent made of zeolite ion-exchanged with calcium ions, or a method in which a material for producing a metal ion-containing non-aqueous solvent made of zeolite ion-exchanged with calcium ions is immersed in a tank containing a liquid to be treated containing a metal ion-containing non-aqueous solvent and allowed to stand or stir. When the liquid to be treated, which contains the metal ion-containing nonaqueous solvent, is passed through a column or tank packed with a metal ion-containing nonaqueous solvent producing material consisting of zeolite ion-exchanged with calcium ions, the speed at which the metal ion-containing nonaqueous solvent is passed (liquid hourly space velocity) may be appropriately selected from the speed at which water in the metal ion-containing nonaqueous solvent can be removed.

[0048] In the method for producing a metal ion-containing nonaqueous solvent according to the present invention, it is preferable to pass a liquid to be treated, which contains the metal ion-containing nonaqueous solvent, in an upward flow manner through a metal ion-containing nonaqueous solvent production material comprising the zeolite ion-exchanged with calcium ions.

[0049] For example, as illustrated in FIG. 1, in the method for producing a metal ion-containing nonaqueous solvent according to the present invention, it is preferable to use a metal ion-containing nonaqueous solvent production apparatus 1, and pass a treatment liquid S containing a metal ion-containing nonaqueous solvent stored in a raw liquid tank 2 in an upward flow manner through a container 3 containing a metal ion-containing nonaqueous solvent production material consisting of zeolite ion-exchanged with calcium ions.

[0050] In this way, by passing the liquid to be treated, which contains the metal ion-containing nonaqueous solvent, in an upward direction through a metal ion-containing nonaqueous solvent manufacturing material consisting of zeolite ion-exchanged with calcium ions contained in a container, even if air bubbles or the like become mixed in the zeolite contained in the container, the air bubbles in the zeolite can be degassed and removed as the liquid to be treated flows upward through the container. Therefore, even if air bubbles or the like are mixed into the zeolite contained in the container, the contact between the liquid to be treated and the zeolite is suitably maintained while the air bubbles or the like are mixed into the liquid to be treated. Moisture can be removed or reduced.

[0051] According to the present invention, it is possible to provide a method for producing a metal ion-containing nonaqueous solvent in which the water content is reduced while preventing contamination with residual cations such as sodium ions. EXAMPLES

[0052] The present invention will now be described in more detail with reference to examples, but these are merely illustrative and do not limit the present invention.

[0053] In the following examples and comparative examples, the water concentration, sodium ion concentration and calcium ion concentration in the electrolyte solution are values ​​measured by the following methods. <Water concentration in electrolyte> Measured by the Karl Fischer method. <Sodium ion concentration and calcium ion concentration in the electrolyte> The measurement was performed by atomic absorption spectrometry using an atomic absorption spectrophotometer (Hitachi, Ltd., ZA3000).

[0054] In the following examples and comparative examples, the sodium content (mass%), calcium content (mass%) and lithium content (mass%) of the zeolite are ) and the lithium ion exchange rate are values ​​measured by the following methods.

[0055] <Sodium content, calcium content and lithium content of zeolite> The sodium content, calcium content and lithium content of the zeolite respectively refer to values ​​determined by the method for measuring the concentration of cationic species in zeolite described below. (Method for measuring the concentration of cationic species in zeolite) 0.1 g of zeolite is dissolved by heating with 5 ml of 47% hydrofluoric acid and 20 ml of 60% nitric acid, and then 1N nitric acid is added to make a 50 ml solution. The concentration (mass%) of each cationic species in this solution is measured using an inductively coupled plasma (ICP) emission spectrometer (PerkinElmer OPTIMA3000DV).

[0056] <Calcium ion exchange rate> The calcium ion exchange rate means a value calculated by the following formula (I). Calcium ion exchange rate (eq%) = {molar equivalent of calcium ions in zeolite (eq) / total molar equivalent of all ion-exchangeable cations in zeolite (eq)} x 100 (I) In the above formula (I), the sum (eq) of the molar equivalents of all ion-exchangeable cations in the zeolite means the sum (eq) of the molar equivalents of calcium ions and sodium ions, which is determined by calculating the content of each cationic species from the concentration of cationic species in the zeolite measured by the above method (method for measuring the concentration of cationic species in zeolite). In addition, in the above formula (I), the molar equivalent (eq) of calcium ions in the zeolite means the molar equivalent (eq) of calcium ions obtained by calculating the content of each cationic species from the concentration of the cationic species in the zeolite measured by the above method.

[0057] <Lithium ion exchange rate> The lithium ion exchange rate means a value calculated by the following formula (II). Lithium ion exchange rate (eq%) = {molar equivalent of lithium ion in zeolite (eq) / total molar equivalent of all ion-exchangeable cations in zeolite (eq)} x 100 (II) In the above formula (II), the sum (eq) of the molar equivalents of all ion-exchangeable cations in the zeolite means the sum (eq) of the molar equivalents of lithium ions and sodium ions, which is determined by calculating the content of each cationic species from the concentration of cationic species in the zeolite measured by the above method (method for measuring the concentration of cationic species in zeolite). In addition, in the above formula (II), the molar equivalent (eq) of lithium ions in the zeolite means the molar equivalent (eq) of lithium ions obtained by calculating the content of each cationic species from the concentration of the cationic species in the zeolite measured by the above method.

[0058] Example 1 <Preparation of zeolite ion-exchanged with calcium ions> 100 parts by weight of sodium A-type zeolite was mixed with 25 parts by weight of kaolin clay, 4 parts by weight of CMC (carboxymethyl cellulose), and water, and then molded into spherical bodies of 1.0 to 2.0 mm. The molded bodies were dried and then fired at 600°C for 3 hours in a box furnace. The fired compact was packed into a column and a 6% aqueous solution of sodium hydroxide was passed through it at 80°C to convert the clay into A-type zeolite (binderless conversion). The binderless compact was more than 95% zeolite. Subsequently, the aqueous sodium hydroxide solution in the column was removed by washing with water, and then the zeolite molded body was subjected to calcium ion exchange. In the calcium ion exchange, a 0.2N aqueous calcium chloride solution was passed through the column at 60°C in one pass to bring the zeolite into contact with the aqueous calcium chloride solution, and the aqueous calcium chloride solution was finally circulated to homogenize the calcium ion exchange rate in the zeolite molded body, thereby preparing an A-type zeolite (a material for manufacturing a metal ion-containing nonaqueous solvent according to the present invention) with a calcium ion exchange rate of 94 eq%. After calcium ion exchange, the zeolite molded body was washed with water, dried, and then calcined at 500° C. for 3 hours to dehydrate the zeolite.

[0059] Example 2 <Preparation of zeolite ion-exchanged with calcium ions> 100 parts by weight of sodium A-type zeolite was mixed with 25 parts by weight of kaolin clay, 4 parts by weight of CMC (carboxymethyl cellulose), and water, and then molded into spherical bodies of 1.0 to 2.0 mm. The molded bodies were dried and then fired at 600°C for 3 hours in a box furnace. The fired compact was packed into a column and a 6% aqueous solution of sodium hydroxide was passed through it at 80°C to convert the clay into A-type zeolite (binderless conversion). The binderless compact was more than 95% zeolite. Subsequently, the aqueous sodium hydroxide solution in the column was removed by washing with water, and then the zeolite molded body was subjected to calcium ion exchange. In the calcium ion exchange, a 0.2N aqueous calcium chloride solution was passed through the column at 60°C in one pass to bring the zeolite into contact with the aqueous calcium chloride solution, and the aqueous calcium chloride solution was finally circulated to homogenize the calcium ion exchange rate in the zeolite molded body, thereby preparing an A-type zeolite (a material for manufacturing a metal ion-containing nonaqueous solvent according to the present invention) with a calcium ion exchange rate of 91 eq%. After calcium ion exchange, the zeolite molded body was washed with water, dried, and then calcined at 500° C. for 3 hours to dehydrate the zeolite.

[0060] (Production Example 1) <Preparation of zeolite ion-exchanged with lithium ions> 100 parts by weight of sodium A-type zeolite was mixed and kneaded with 25 parts by weight of kaolin clay, 4 parts by weight of CMC (carboxymethyl cellulose), and water to form spherical bodies of 1.0 to 2.0 mm. After drying, the bodies were fired at 600°C for 3 hours in a box furnace. The fired compact was packed into a column and a 6% aqueous solution of sodium hydroxide was passed through it at 80°C to convert the clay into A-type zeolite (binderless conversion). The binderless compact was more than 95% zeolite. Subsequently, the aqueous sodium hydroxide solution in the column was washed with water to remove it, and then the zeolite molded body was subjected to lithium ion exchange. For the lithium ion exchange, a 15-fold equivalent amount of 4 mol / L aqueous lithium chloride solution was passed through the column at 80°C in one pass to bring the zeolite into contact with the aqueous lithium chloride solution. This homogenized the lithium ion exchange rate in the zeolite molded body. After the lithium ion exchange, the zeolite molded body was washed with water, dried at 70°C, and then calcined at 500°C for 3 hours to dehydrate the zeolite. The lithium ion exchange rate of the obtained lithium ion-exchanged A-type zeolite shaped body was 99 eq%.

[0061] (Production Example 2) <Preparation of zeolite ion-exchanged with calcium ions> 100 parts by weight of sodium A-type zeolite was mixed with 25 parts by weight of kaolin clay, 4 parts by weight of CMC (carboxymethyl cellulose), and water, and then molded into spherical bodies of 1.0 to 2.0 mm. The molded bodies were dried and then fired at 600°C for 3 hours in a box furnace. The fired compact was packed into a column and a 6% aqueous solution of sodium hydroxide was passed through it at 80°C to convert the clay into A-type zeolite (binderless conversion). The binderless compact was more than 95% zeolite. The aqueous sodium hydroxide solution in the column was then washed away, and the zeolite molded body was then subjected to calcium ion exchange. In the calcium ion exchange, a 0.2N aqueous calcium chloride solution was passed through the column at 60°C in one pass to bring the zeolite into contact with the aqueous calcium chloride solution, and the aqueous calcium chloride solution was finally circulated to homogenize the calcium ion exchange rate in the zeolite molded body, thereby preparing an A-type zeolite with a calcium ion exchange rate of 86 eq%. After calcium ion exchange, the zeolite molded body was washed with water, dried, and then calcined at 500° C. for 3 hours to dehydrate the zeolite.

[0062] Example 3 An electrolyte solution for lithium ion batteries was prepared using a production apparatus 1 for a metal ion-containing nonaqueous solvent shown in FIG. That is, first, as shown in FIG. 1, in a metal ion-containing nonaqueous solvent manufacturing apparatus (lithium ion battery electrolyte manufacturing apparatus) 1, the A-type zeolite (metal ion-containing nonaqueous solvent manufacturing material) having a calcium ion exchange rate of 94 eq% obtained in Example 1 was placed in a container 3. The liquid to be treated S was 1 kg (0.8 L) of liquid to be treated, which was a mixed solvent of ethylene carbonate (EC) and dimethyl carbonate (DMC) mixed in a volume ratio of 1:1 and in which LiPF6 was dissolved to a concentration of 1 mol / L, and which had a water concentration of 40 ppm by mass and a sodium ion concentration of less than 1 ppm by mass. The liquid was passed through 20 ml of zeolite in the container 3 in an upward flow rate of 5 (L / L-zeolite) / h using pump P, and the treated liquid (electrolyte) after the liquid passing was stored in the recovery tank 4. One hour after the start of the flow of the electrolyte, the treated liquid (electrolyte) was sampled, and the water concentration, sodium ion concentration, and calcium ion concentration in the obtained electrolyte were measured. The results are shown in Table 1.

[0063] Example 4 An electrolyte for lithium ion batteries was obtained in the same manner as in Example 3, except that the A-type zeolite having a calcium ion exchange rate of 91 eq% obtained in Example 2 was used instead of the A-type zeolite having a calcium ion exchange rate of 94 eq%. The water concentration, sodium ion concentration, and calcium ion concentration in the obtained electrolyte were measured. The results are shown in Table 1.

[0064] Comparative Example 1 Instead of the A-type zeolite with a calcium ion exchange rate of 94 eq%, the lithium ion exchange rate was 94 eq%. A lithium ion battery electrolyte solution was obtained in the same manner as in Example 3, except that an A-type zeolite having a molecular weight of 99 eq% (a zeolite in which cations equivalent to 99 eq% of the molar equivalents of all ion-exchangeable cations are ion-exchanged with lithium ions) was used. The water concentration, sodium ion concentration, and calcium ion concentration in the obtained electrolyte were measured. The results are shown in Table 1.

[0065] Comparative Example 2 An electrolyte for lithium ion batteries was obtained in the same manner as in Example 3, except that the A-type zeolite having a calcium ion exchange rate of 86 eq% obtained in Production Example 2 was used instead of the A-type zeolite having a calcium ion exchange rate of 94 eq%. The water concentration, sodium ion concentration, and calcium ion concentration in the obtained electrolyte were measured. The results are shown in Table 1.

[0066] [Table 1]

[0067] As can be seen from Table 1, in Examples 3 and 4, the liquid to be treated was treated using zeolite in which cations equivalent to 88 eq% or more of all ion-exchangeable cations were ion-exchanged with calcium ions, and therefore it was possible to produce an electrolyte for lithium-ion batteries in which the water concentration was reduced from 40 ppm by mass to less than 10 ppm by mass while suppressing the elution of not only sodium ions remaining in the zeolite but also calcium ions.

[0068] On the other hand, in Comparative Example 1 and Comparative Example 2, zeolite exchanged with lithium ions instead of calcium ions (Comparative Example 1) and zeolite with a calcium ion exchange rate of 86 eq% (Comparative Example 2) are used, and therefore it is found that the elution of sodium ions remaining in the zeolite cannot be sufficiently suppressed.

[0069] Furthermore, when Example 3 and Comparative Example 1 are compared, it is found that the zeolite ion-exchanged with calcium ions (Example 1) has a higher sodium content than the zeolite ion-exchanged with lithium ions (Comparative Example 1), yet has a lower amount of eluted sodium ions, and therefore the zeolite ion-exchanged with calcium ions (Example 3) has a unique effect of suppressing the elution of sodium ions. For this reason, it is understood that a zeolite ion-exchanged with calcium ions can be used to produce an electrolyte solution for lithium ion batteries having a lower sodium ion content than a zeolite ion-exchanged with lithium ions. [Industrial Applicability]

[0070] According to the present invention, it is possible to provide a material for producing a metal ion-containing nonaqueous solvent, which can produce a metal ion-containing nonaqueous solvent having a reduced water content while suppressing the inclusion of residual cations such as sodium ions, and a method for producing a metal ion-containing nonaqueous solvent. [Explanation of symbols]

[0071] 1. Apparatus for producing metal ion-containing non-aqueous solvent 2. Stock solution tank 3 containers 4. Recovery Tank S Liquid to be treated P-Pump

Claims

1. A material for producing a metal ion-containing non-aqueous solvent, comprising a zeolite in which cations corresponding to 88 eq % or more of all ion-exchangeable cations are ion-exchanged with calcium ions.

2. A method for producing a metal ion-containing non-aqueous solvent, comprising contacting a liquid to be treated, the liquid containing the metal ion-containing non-aqueous solvent, with a material for producing a metal ion-containing non-aqueous solvent, the material being made of zeolite in which cations corresponding to 88 eq% or more of all ion-exchangeable cations have been ion-exchanged with calcium ions.

3. 3. The method for producing a non-aqueous solvent containing metal ions according to claim 2, wherein the non-aqueous solvent containing metal ions is a non-aqueous electrolyte solution in which 0.01 eq / L or more of a metal salt electrolyte is dissolved in the non-aqueous solvent.

4. 4. The method for producing a metal ion-containing nonaqueous solvent according to claim 2, wherein a liquid to be treated containing the metal ion-containing nonaqueous solvent is passed through the metal ion-containing nonaqueous solvent producing material made of zeolite in an upward flow manner.

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