JP6721861B2 - Amorphous aluminosilicate particle powder containing lithium and method for producing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a highly pure lithium-containing amorphous aluminosilicate particle powder having a water adsorption property and a method for producing the same.

In recent years, due to various problems related to energy resources, efforts have been focused on sustainable energy use and development. Among them, the lithium ion battery has a higher energy density than other batteries, so that it has been developed from a drive power source for portable devices to a power source for large-scale applications.

Conventionally, a water-based electrolytic solution has been mainly used for a chemical battery, but since a lithium ion battery has a high voltage of 3 V or more, an organic solvent-based electrolytic solution having a stable potential window is used. Since an electrolyte containing fluorine is used in the electrolytic solution, it is indispensable to remove water from the constituent members from the manufacturing process to the time of use. Although the doctor blade method of the electrode paint is used for the production of the electrode sheet, the paint solvent is mainly organic and the water content management is very important.

As is well known, an organic solvent having a high affinity with water is easy to take water into the system although it is a trace amount from the atmosphere. The taken-in water reacts with the electrolyte containing fluorine in the electrolytic solution to generate hydrofluoric acid, destroys the constituent materials of the lithium ion battery, and shortens the life of the battery. Therefore, the organic solvent used for producing the lithium-ion battery requires extreme water management and dehydration treatment.

In addition, a lithium ion battery causes an electrochemical reaction of desorption and insertion of Li ⁺ ions at the electrode/electrolyte interface during use, but there are side reactions that adversely affect the life of the battery due to the influence of temperature and impurity ions. It is also known to wake up. Therefore, it is desired to reduce foreign elements inside the lithium-ion battery as much as possible.

Examples of the dehydration treatment include distillation using a difference in boiling points and addition of a water adsorbent, and zeolite and amorphous aluminosilicate particle powder have been studied as the water adsorbent (Patent Documents 1 and 2). ..

JP, 2008-179533, A JP, 2011-71111, A

In the production of lithium ion batteries, a water adsorbent having high purity and high adsorption capacity is currently most demanded, but a sufficient water adsorbent has not yet been obtained.

That is, in the technique described in Patent Document 1, amorphous aluminosilicate particles are presented as a water adsorbent, but it is unclear whether they are effective in the dehydration treatment of the solvent used in the production of lithium ion batteries, and ion exchange As a result, the elution of sodium ions into the electrolytic solution becomes a problem.

Further, in the technique described in Patent Document 2, considering the long-term use of the lithium-ion battery, sodium that is not ion-exchanged and remains in the zeolite becomes a problem.

Therefore, the technical problem of the present invention is to provide a highly pure lithium-containing amorphous aluminosilicate particle powder having a high water adsorption performance and a method for producing the same.

The above technical problems can be achieved by the present invention as described below.

That is, in the present invention, the Si/Al molar ratio is 1.5 to 5.0, the lithium concentration is 1.0 to 5.0 wt %, and the impurity sodium and sulfur concentrations are each 0.1 wt% or less. It is an amorphous aluminosilicate particle powder containing certain lithium. (Invention 1).

Further, the present invention provides a lithium-containing amorphous aluminosilicate particle powder according to the present invention 1, wherein the molar ratio Li/(Si+Al) of Li to the total amount of Si and Al is 0.15 to 0.60. Is. (Invention 2).

Further, the present invention is the lithium-containing amorphous aluminosilicate particle powder according to the present invention 1 or 2, which has a BET specific surface area of 10 to 150 m ² /g. (Invention 3)

Further, the present invention comprises a lithium according to any one of the present invention 1 to 3, wherein the water-soluble lithium concentration is 500 to 6000 ppm, and the water-soluble sodium concentration and the water-soluble sulfur concentration are each 10 ppm or less. It is a crystalline aluminosilicate particle powder. (Invention 4)

Further, the present invention is a spherical or columnar tablet formed product using the amorphous aluminosilicate particles containing lithium according to any one of the first to fourth inventions. (Invention 5)

Further, the present invention is a moisture adsorbent using the lithium-containing amorphous aluminosilicate particles according to any one of the present inventions 1 to 4 or the tablet molding according to claim 5. (Invention 6)

Further, according to the present invention, a water-soluble silicon raw material containing lithium whose sodium concentration is 1 wt% or less and a water-soluble aluminum raw material whose sodium concentration is 1 wt% or less have a Si/Al molar ratio of 2.0 to 10.0. Then, the present invention is characterized in that an aging reaction is carried out at 20 to 105° C. after adding an alkaline raw material having a sodium concentration of 1 wt% or less so that the pH of the reaction solution becomes 8.0 to 13.0. The method for producing a lithium-containing amorphous aluminosilicate particle powder according to any one of 1 to 4. (Invention 7)

The lithium-containing amorphous aluminosilicate particle powder according to the present invention (hereinafter referred to as aluminosilicate particle powder) is suitable as a water adsorbent in an organic solvent because it has a high purity and an excellent water adsorbing ability. .. In particular, it is possible to adsorb and remove water from the lithium ion electrolytic solution and the organic solvent used in the manufacturing process thereof. Furthermore, since the aluminosilicate particle powder according to the present invention does not contain sodium as a main component raw material of the reaction, the amount of sodium contained is extremely small, and the obtained lithium ion battery can be used for a long period of time.

3 is an X-ray diffraction pattern of the particle powder obtained in Example 1. 3 is a transmission electron microscope photograph of the particle powder obtained in Example 1. 3 is an X-ray diffraction pattern of the particle powder obtained in Comparative Example 2.

The structure of the present invention will be described in more detail below.

The aluminosilicate particle powder according to the present invention is an aluminosilicate particle powder containing lithium and is amorphous. The chemical structure is represented by the general formula x Li ₂ O.y SiO ₂ .z Al ₂ O ₃ .n H ₂ O. Since Si ⁴⁺ and ^{Al 3+} is that there are places to share ^{O 2-} one another, ^{Si 4+} surrounding be electrically neutral, ^{Al 3+} peripheral is charged as a minus monovalent. Therefore, the periphery of Al ³⁺ is supplemented with Li ⁺ so as to be electrically neutral. The Li ⁺ ions are ion-exchanged by the atmosphere and may be discharged out of the system of the particle powder.

The aluminosilicate particle powder according to the present invention has a Si/Al molar ratio of 1.5 to 5.0. If the Si/Al molar ratio is less than 1.5, the concentration of anions such as sulfate ions in impurities in the resulting particle powder increases, and the impurities elute into the organic solvent as ions during actual use. Not preferable. When the Si/Al molar ratio exceeds 5.0, the particle powder is reacted at the composition ratio to synthesize the powder, resulting in a very low yield, which is not preferable from an industrial viewpoint. The Si/Al molar ratio is preferably 1.8 to 4.5, and more preferably 2.0 to 4.0. The anion is an anion derived from a raw material, and is NO ₃ ⁻ ion, Cl ⁻ ion, CO ₃ ²⁻ ion or the like.

The lithium concentration of the aluminosilicate particle powder according to the present invention is 1.0 to 5.0 wt% (wt %). When the lithium concentration is less than 1.0 wt %, the water adsorption performance tends to be extremely reduced. If it exceeds 5.0 wt %, the form cannot be sufficiently washed with water, and the residual sodium and sulfur concentrations increase. It is preferably 1.2 to 4.8 wt%, more preferably 1.5 to 4.5 wt%.

The sulfur concentration of the aluminosilicate particle powder according to the present invention is 0.1 wt% or less. When it exceeds 0.1 wt %, the amount of sulfur eluted from the particle powder cannot be ignored when used as an adsorbent. It is preferably 0.09 wt %. The lower limit of the sulfur concentration is usually 0.01 wt %.

The sodium concentration of the aluminosilicate particle powder according to the present invention is 0.1 wt% or less. When it exceeds 0.1 wt %, the elution amount of sodium from the particle powder cannot be ignored when it is used as an adsorbent. It is preferably 0.09 wt %. The lower limit of sodium concentration is usually 0.01 wt %.

The molar ratio Li/(Si+Al) of the lithium content to the total amount of Si and Al of the aluminosilicate particle powder according to the present invention is preferably 0.15 to 0.60. When it is less than 0.15, the content of lithium is small and the water adsorption capacity is lowered, which is not preferable. When it is 0.60 or more, washing with water becomes difficult, and a large amount of impurities sulfur and sodium are also held, which is not preferable. The molar ratio is more preferably 0.16 to 0.58, still more preferably 0.18 to 0.55.

The BET specific surface area of the aluminosilicate particle powder according to the present invention is preferably 10 to 150 m ² /g. If it is less than 10 m ² /g, the water adsorption capacity will decrease, which is not preferable. When it exceeds 150 m ² /g, the filtration efficiency at the time of synthesis is deteriorated and the productivity is lowered, which is not preferable. It is more preferably 15 to 120 m ² /g, and even more preferably 20 to 100 m ² /g.

The water-soluble lithium concentration of the aluminosilicate particle powder according to the present invention is preferably 500 to 6000 ppm. When it is less than 500 ppm, the amount of lithium that can be provided outside the amorphous aluminosilicate particles is small, which is not preferable. When it exceeds 6000 ppm, it is not preferable because the washing with water is insufficient, and impurities such as sodium and sulfur also remain at a high concentration. It is more preferably 600 to 5800 ppm, and even more preferably 700 to 5500 ppm.

The aluminosilicate particle powder according to the present invention preferably has a water-soluble sulfur concentration of 10 ppm or less and a water-soluble Na concentration of 10 ppm or less. The lower limits of the water-soluble sulfur concentration and the water-soluble sodium concentration are usually 0.01 ppm.

The shape of the aluminosilicate particle powder in the present invention is preferably granular or plate-like.

The aluminosilicate particle powder according to the present invention can also be formed into a tablet-shaped product having a spherical shape, a cylindrical shape, or the like. This is because, unlike the powder, by molding, the handling becomes easier and the applications as a cation exchanger and a gas molecule adsorbent are expanded. A resin may be used in combination as the binder of the molded body. The resin component is not particularly limited to polyurethane resin, vinylidene chloride resin, acrylic resin, etc., and a copolymer obtained by copolymerizing urethane, vinylidene chloride, etc. with acrylate, acrylonitrile, etc. is also a resin component of the present invention. Is effective as. Further, if necessary, an epoxy-based or melamine-based cross-linking agent and other additives can be added. It is also possible to reduce the amount of the adsorbent component used by adding a third component that serves as a nucleus for granulation and forming a complex of the adsorbent and the resin component around the nucleus.

The aluminosilicate particle powder according to the present invention is preferably used as a moisture adsorbent. The form of use as the adsorbent is not particularly limited, but addition to an organic solvent or contact with a gas from which water is desired to be removed may be used.

As the organic solvent, N-methylpyrrolidone, ethyl acetate, butyl acetate, methyl ethyl ketone, acetone, isopropyl alcohol, methanol, ethanol, toluene, xylene, cyclohexane, n-hexane and the like are preferable, and the addition amount to the organic solvent is 0.1 wt%. It is preferably 10 wt%.

Next, a method for producing the aluminosilicate particle powder according to the present invention will be described.

In the present invention, the water-soluble silicon raw material containing lithium having a sodium concentration of 1 wt% or less and the water-soluble aluminum raw material having a sodium concentration of 1 wt% or less have a Si/Al molar ratio of 2.0 to 10.0. Then, after adding an alkaline raw material having a sodium concentration of 1 wt% or less so that the pH of the reaction solution becomes 8.0 to 13.0, an aging reaction is performed at 20 to 105° C. to obtain lithium-containing aluminosilicate. A salt particle powder can be obtained.

The sodium concentration of each raw material of the aluminosilicate particle powder according to the present invention is preferably 1 wt% or less. When it exceeds 1 wt %, the concentration of sodium impurities in the obtained aluminosilicate particle powder becomes remarkable. It can be synthesized from a raw material in a solution reaction by a method in which sodium is reduced to 1 wt% or less. The lower limit of the sodium concentration of the raw material is usually 0.01 wt %.

The raw material of the aluminosilicate particle powder according to the present invention is preferably a water-soluble silicon raw material containing lithium, a water-soluble aluminum raw material, and an alkali raw material. By using a water-soluble raw material, it is possible to prepare a uniform particle powder by dissolving the raw material in water in advance and mixing the raw materials in a uniform state. As the water-soluble silicon raw material, lithium silicate, lithium orthosilicate, or the like can be used. As the water-soluble aluminum raw material, aluminum sulfate, aluminum nitrate, aluminum chloride or the like can be used. Examples of the alkaline raw material include lithium carbonate aqueous solution, ammonium carbonate aqueous solution, and potassium carbonate aqueous solution as the alkali carbonate aqueous solution, and lithium hydroxide aqueous solution, potassium hydroxide aqueous solution, and the like can be used as the alkali hydroxide aqueous solution.

In the method for producing aluminosilicate particle powder according to the present invention, the Si/Al molar ratio mixing condition is preferably 2.0 to 10.0. When it is less than 2.0, the amount of anions derived from the raw materials remaining as impurities increases, which is not preferable. When it exceeds 10.0, the yield obtained as the above-mentioned particle powder is significantly reduced, which is not preferable. The more preferable Si/Al molar ratio is 2.2 to 8.0, and even more preferably 2.5 to 6.0.

In the method for producing aluminosilicate particle powder according to the present invention, the pH immediately after mixing the alkali raw materials is preferably 8.0 to 13.0. If the pH is less than 8.0, the lithium content in the aluminosilicate particles will be low, which is not preferable. When the pH exceeds 13.0, the aluminosilicate particle powder is dissolved and the yield is reduced, which is not preferable. A more preferable range is pH 9.0 to 12.5, and an even more preferable range is pH 10.0 to 12.0.

In the method for producing aluminosilicate particle powder according to the present invention, the aging reaction temperature is preferably 20 to 105°C. If the temperature is lower than 20° C., the viscosity of the reaction mother liquor becomes high and uniform mixing becomes difficult, which is not preferable. If the temperature exceeds 105°C, an expensive closed reaction vessel is required, and further, the obtained particle powder is agglomerated, the specific surface area is reduced, and as a result, the water adsorption capacity is reduced, which is not preferable. A more preferred range is 30 to 95°C, and an even more preferred range is 50 to 95°C.

The compatibility of the aluminosilicate particle powder of the present invention with the resin can be controlled by subjecting the particle powder to a dry surface treatment with an organic substance or the like. Examples of the surface treatment agent include rosin compounds, silane coupling agents, and higher fatty acids. The amount of the aluminosilicate particle powder coated with the surface treatment agent is preferably 0.1 to 5% by weight in terms of carbon amount. As the dry type surface treatment machine, a raker machine, a vibration mill, a roller type mixer or the like can be used.

<Action>
The high water adsorption capacity of the aluminosilicate particle powder according to the present invention is obtained by optimizing the Si/Al composition ratio of the aluminosilicate and the lithium concentration, thereby increasing the number of hydrophilic -OH groups on the particle powder surface. The present inventors presume that the presence of the cation-exchangeable -OLi group of

A typical embodiment of the present invention is as follows.

The crystal phase/amorphous phase of the aluminosilicate particle powder according to the present invention is determined by "X-ray diffractometer RINT2500 (manufactured by Rigaku Denki Co., Ltd.)" (tube: Cu, tube voltage: 40 kV, tube current: 300 mA, goniometer: wide-angle goniometer, sampling width: 0.010°, scanning speed: 4.00°/min, divergence slit: 1/2°, scattering slit: 1/2°, light receiving slit: 0.15 mm) Was done using. In addition, the primary particle size was estimated by observation with a transmission microscope (100 kV).

The analysis of the content of light elements such as Li of the aluminosilicate particle powder according to the present invention is performed by melting the powder with a melting agent of sodium carbonate:boric acid=4:1, and then measuring “plasma emission spectroscopy analyzer SPS4000 (Seiko Denshi). Industrial Co., Ltd.”. The contents of Na, Si, Al, and S of the adsorbent according to the present invention were determined using a fluorescence X-ray analyzer Rigaku RIX2100.

The BET specific surface area of the aluminosilicate particle powder according to the present invention is a value measured by the BET method.

The water content in the solvent was measured using a "trace water content measuring device AQ-2200A (manufactured by Hiranuma Sangyo Co., Ltd.)".

The concentration of the water-soluble salt in the aluminosilicate particle powder according to the present invention is 20 parts after adding 100 parts by weight of water to 5 parts by weight of amorphous aluminosilicate particles and boiling for 15 minutes while stirring with a stirrer. It was measured by using a filtrate obtained by cooling under reduced pressure for 15 minutes in a constant temperature bath at 0° C. with a 0.2 μm membrane filter as an eluent. The evaluation of the concentrations of lithium ion, sodium ion and sulfate ion in the eluate was measured by "plasma emission spectroscopic analyzer SPS4000 (Seiko Denshi Kogyo KK)". The concentration of the obtained ion was multiplied by 20 to obtain the water-soluble salt concentration. The pH of the eluate at 20° C. was defined as the powder pH.

Example 1: Production of amorphous aluminosilicate particle powder In a reaction vessel having an internal volume of 100 l, 20 l of a 2.0 mol/l lithium silicate solution as Si was charged, and then Al ³⁺ 0.5 mol/l sulfuric acid. 40 l of an aluminum solution was added and mixed, then a 3N LiOH solution was added dropwise until the pH reached 12.0, and water was further added to adjust the solution amount to 85 l and the temperature to 35°C.

The above suspension was stirred at a temperature of 35° C. for 1 hour to carry out an aging reaction. The pH of the obtained white suspension solution was 11.5. Next, it was filtered, washed with water, dried and pulverized.

The obtained white particle powder was amorphous as a result of X-ray diffraction shown in FIG. Incidentally, since the X-ray diffraction patterns of the other examples also had the same peak pattern, it was presumed that a halo peak derived from an amorphous substance was merely obtained instead of a broad crystalline peak. There is. As a result of composition analysis, the Si/Al molar ratio was 1.77, the Li/(Si+Al) molar ratio was 0.309, the Li concentration was 2.81 wt %, the Na concentration was 0.085 wt %, and the S concentration was 0.077 wt %. there were. From the transmission electron microscope photograph shown in FIG. 2, primary particles of about 10 to 30 nm were observed.

The white powder obtained had a water-soluble salt Li concentration of 2026 ppm, a water-soluble salt Na concentration of 8 ppm, and a water-soluble salt sulfur concentration of less than 0.01 ppm.

Examples 2-10, Comparative Examples 1-4
Same as Example 1 except that the alkaline aqueous solution, the water-soluble silicon aqueous solution, the type of the water-soluble aluminum, the type, the concentration, the amount of the additive element raw material, and the aging reaction temperature/time in the adsorbent formation reaction were changed. To produce hydrous aluminosilicate particles.

Table 1 shows the production conditions at this time, and Table 2 shows various characteristics of the obtained aluminosilicate particles.

The white particle powder obtained in Comparative Example 2 was eucryptite having crystallinity as a result of X-ray diffraction shown in FIG.

To 100 ml of N-methylpyrrolidone adjusted to have a water content of 2000 ppm by dropping water, 1 g of each powder of Example 1 and Comparative Example 1 was individually added, and then the container was closed for 1 hour. The water content in the organic solvent that was allowed to stand was measured.

The initial water content was 2000 ppm, the content of the powder of Example 1 was 260 ppm, and the content of the powder of Comparative Example 1 was 180 ppm.

After 50 ml of N-methylpyrrolidone to which the powder was added was filtered under reduced pressure with a filter having a mesh width of 0.45 μm, the residue after evaporation of N-methylpyrrolidone was dissolved in 50 ml of water to adjust the Na and S concentrations to “plasma emission spectroscopy analyzer SPS4000( Seiko Denshi Kogyo Co., Ltd.”. Although neither Na nor S was detected (less than 0.01 ppm) from the residue of N-methylpyrrolidone to which the powder of Example 1 was added, Na was detected from the residue of N-methylpyrrolidone to which the powder of Comparative Example 1 was added. 14 ppm and 160 ppm of S were detected.

Since the amorphous aluminosilicate particles containing Li according to the present invention can adsorb water from a solvent and have a very small amount of sodium impurity, adsorption of water from a solvent used in a lithium ion battery or an electrolytic solution It is suitable as an agent.

Claims (7)

A Si/Al molar ratio of 1.5 to 5.0, a lithium concentration of 1.0 to 5.0 wt%, and a lithium-containing non-concentration of impurities of sodium and sulfur of 0.1 wt% or less, respectively. Crystalline aluminosilicate particle powder. The lithium-containing amorphous aluminosilicate particle powder according to claim 1, wherein a molar ratio Li/(Si+Al) of Li to the total amount of Si and Al is 0.15 to 0.60. The lithium-containing amorphous aluminosilicate particle powder according to claim 1, which has a BET specific surface area of 10 to 150 m ² /g. The lithium-containing amorphous aluminosilicate particles according to claim 1, wherein the water-soluble lithium concentration is 500 to 6000 ppm, and the water-soluble sodium concentration and the water-soluble sulfur concentration are each 10 ppm or less. Powder. A spherical or columnar tablet compact using the amorphous aluminosilicate particles containing lithium according to any one of claims 1 to 4. A moisture adsorbent using the lithium-containing amorphous aluminosilicate particles according to any one of claims 1 to 4 or the tablet molding according to claim 5. The water-soluble silicon raw material containing lithium having a sodium concentration of 1 wt% or less and the water-soluble aluminum raw material having a sodium concentration of 1 wt% or less have a Si/Al molar ratio of 2.0 to 10.0. 5. The aging reaction is carried out at 20 to 105[deg.] C. after adding an alkaline raw material having a sodium concentration of 1 wt% or less so that the pH of the solution becomes 8.0 to 13.0. 5. A method for producing a lithium-containing amorphous aluminosilicate particle powder according to [4].