JP2019071290A - Electroconductive material for lithium ion secondary battery, composition for forming lithium ion secondary battery negative electrode, composition for forming lithium ion secondary battery positive electrode, negative electrode for lithium ion secondary battery, positive electrode for lithium ion secondary battery, and lithium ion secondary battery - Google Patents

Abstract

To provide: an electroconductive material for a lithium ion secondary battery, which can impart superior electrical characteristics and lifetime characteristics to a lithium ion secondary battery; a composition for forming a lithium ion secondary battery negative electrode, a composition for forming a lithium ion secondary battery positive electrode, a negative electrode for a lithium ion secondary battery, and a positive electrode for a lithium ion secondary battery, in which the electroconductive material for a lithium ion secondary battery is used; and a lithium ion secondary battery.SOLUTION: An electroconductive material for a lithium ion secondary battery contains an aluminum silicate complex that comprises an aluminum silicate and carbon that is disposed on a surface of the aluminum silicate.SELECTED DRAWING: None

Description

  The present invention relates to a conductive material for lithium ion secondary batteries, a composition for forming a lithium ion secondary battery negative electrode, a composition for forming a lithium ion secondary battery positive electrode, a negative electrode for lithium ion secondary batteries, a positive electrode for lithium ion secondary batteries The present invention relates to a lithium ion secondary battery.

  Lithium ion secondary batteries are lighter in weight than other secondary batteries such as nickel hydrogen batteries and lead storage batteries, and have high input / output characteristics. Therefore, lithium ion secondary batteries are highly used in electric vehicles, hybrid electric vehicles, etc. in recent years. It attracts attention as an output power supply.

  As an electrode of a lithium ion secondary battery, a positive electrode having a lithium compound containing Fe or Mn as a metal element as a positive electrode active material, and a negative electrode having a carbon material capable of absorbing and desorbing lithium ions as a negative electrode active material , Is used. Adding a carbon material such as carbon black (for example, acetylene black) as a conductive aid to the positive electrode material or the negative electrode material in order to improve the conductivity of the positive electrode active material in the positive electrode or the charge / discharge characteristics of the negative electrode Are known (see, for example, Patent Document 1).

On the other hand, if impurities (magnetic impurities such as Fe, Ni, Cu, etc.) are present in the constituent material of the battery, the impurities may be precipitated on the negative electrode during charge and discharge. Impurities deposited on the negative electrode can cause a short circuit by breaking the separator and reaching the positive electrode. In addition, lithium ion secondary batteries may be used in vehicles during summer. In this case, the operating temperature of the lithium ion secondary battery may be 40 ° C to 80 ° C. At this time, the metal in the Li-containing metal oxide that constitutes the positive electrode may elute from the positive electrode, and the characteristics of the battery may be degraded.
For this reason, studies of impurity scavengers or adsorbents (hereinafter simply referred to as adsorbents) and studies of stabilization of the positive electrode have been made (see, for example, Patent Document 2).

JP, 2011-181229, A JP 2000-77103 A

  With the increasing demand for the characteristics of lithium ion secondary batteries, the demand for both the electrical characteristics and the life characteristics of lithium ion secondary batteries is increasing. Therefore, the present invention provides a conductive material for a lithium ion secondary battery capable of imparting excellent electric characteristics and life characteristics of the lithium ion secondary battery, and a lithium ion secondary battery negative electrode using the conductive material for a lithium ion secondary battery. It is an object of the present invention to provide a composition for forming a lithium ion secondary battery positive electrode, a lithium ion secondary battery negative electrode, a lithium ion secondary battery positive electrode, and a lithium ion secondary battery.

The present invention is as follows.
<1> aluminum silicate,
Carbon disposed on the surface of the aluminum silicate,
An electrically conductive material for a lithium ion secondary battery, comprising an aluminum silicate composite having:

<2> The conductive material for a lithium ion secondary battery according to <1>, wherein a carbon content ratio in the aluminum silicate composite is 0.1% by mass to 50% by mass.

The electroconductive material for lithium ion secondary batteries as described in said <1> or <2> whose R value obtained from the Raman spectrum analysis of <3> said aluminum silicate complex is 0.1-5.0.

<4> For the lithium ion secondary battery according to any one of <1> to <3>, wherein the powder resistivity of the aluminum silicate complex is 0.001 Ω · cm to 100 Ω · cm. Conductive material.

The element molar ratio Si / Al of the silicon (Si) with respect to aluminum (Al) in the <5> said aluminum silicate complex is 0.1-500 in any one of said <1>-<4> The electroconductive material for lithium ion secondary batteries as described.

<6> For forming a lithium ion secondary battery negative electrode, containing the conductive material for a lithium ion secondary battery according to any one of <1> to <5>, a negative electrode active material, and a binder. Composition.

<7> For forming a lithium ion secondary battery positive electrode, containing the conductive material for a lithium ion secondary battery according to any one of <1> to <5>, a positive electrode active material, and a binder. Composition.

<8> current collector,
A negative electrode layer provided on the current collector and containing the conductive material for a lithium ion secondary battery according to any one of <1> to <5> and a negative electrode active material;
A negative electrode for a lithium ion secondary battery having the

<9> current collector,
A positive electrode layer provided on the current collector and containing the conductive material for a lithium ion secondary battery according to any one of <1> to <5> and a positive electrode active material;
The positive electrode for lithium ion secondary batteries which has.

<10> A lithium ion secondary battery comprising at least one of the negative electrode for a lithium ion secondary battery according to <8> and the positive electrode for a lithium ion secondary battery according to <9>.

  According to the present invention, a conductive material for a lithium ion secondary battery capable of imparting excellent electric characteristics and life characteristics of the lithium ion secondary battery, and a lithium ion secondary battery negative electrode using the conductive material for a lithium ion secondary battery The composition for formation, the composition for lithium ion secondary battery positive electrode formation, the negative electrode for lithium ion secondary batteries, the positive electrode for lithium ion secondary batteries, and a lithium ion secondary battery can be provided.

It is a ²⁷ Al-NMR spectrum of the aluminum silicate which concerns on manufacture example 1 and preparation example 2. FIG. It is a ²⁹ Si-NMR spectrum of the aluminum silicate which concerns on manufacture example 1 and preparation example 2. FIG. It is a powder X-ray-diffraction spectrum of the aluminum silicate which concerns on manufacture example 1 and manufacture example 2. FIG. It is a transmission electron microscope (TEM) photograph of the aluminum silicate which concerns on manufacture example 1. FIG. It is a transmission electron microscope (TEM) photograph of the aluminum silicate which concerns on manufacture example 2. FIG. It is a figure which shows typically tubular imogolite which is an example of aluminum silicate. It is a schematic sectional drawing which shows an example of a structure of an aluminum silicate complex. It is a schematic sectional drawing which shows the other example of a structure of aluminum silicate complex. It is a schematic sectional drawing which shows the other example of a structure of aluminum silicate complex. It is a schematic sectional drawing which shows the other example of a structure of aluminum silicate complex. It is a schematic sectional drawing which shows the other example of a structure of aluminum silicate complex. It is a powder X-ray-diffraction spectrum of each sample in an Example. It is a graph which shows the evaluation result of the metal (Mn) ion adsorption capability in the electrolyte solution of each sample in an Example. It is a graph which shows the evaluation result of the charge / discharge characteristic of the sample A in the Example, and the baked product A. It is a graph which shows the evaluation result of the charge / discharge characteristic of imogolite complex A, imogolite complex B, and acetylene black in an Example.

  In the present specification, the term "step" is included in the term if the intended purpose of the step is achieved, even if it can not be distinguished clearly from the other steps, not only an independent step. . Moreover, the numerical range shown using "-" in this specification shows the range which includes the numerical value described before and after "-" as minimum value and the maximum value, respectively. Furthermore, in the present specification, the amount of each component in the composition refers to the total amount of the plurality of substances present in the composition unless a plurality of substances corresponding to each component are present in the composition. means.

  The conductive material for a lithium ion secondary battery of the present invention comprises an aluminum silicate composite having aluminum silicate and carbon disposed on the surface of the aluminum silicate. The conductive material for a lithium ion secondary battery of the present invention can improve the electrical characteristics and the life characteristics of the lithium ion secondary battery by adopting the above configuration.

  The aluminum silicate contained in the conductive material for lithium ion secondary batteries is an oxide salt containing aluminum (Al) and silicon (Si). Since Si and Al have different valences, a large number of OH groups exist in the oxide salts of Si and Al, which have ion exchange ability. Thus, aluminum silicate has many metal ion adsorption sites per unit mass, and highly selectively adsorbs metal ions with a high specific surface area. The aluminum silicate complex is unique in that it is particularly easy to adsorb transition metal ions such as nickel ions, manganese ions, cobalt ions, copper ions and iron ions than alkali metal ions such as lithium ions and sodium ions. It tends to show the nature.

  Among the aluminum silicate complexes as described above, the element molar ratio Si / of silicon (Si) to aluminum (Al) in the aluminum silicate complex in view of the metal ion adsorption ability and the metal ion selectivity. Al is preferably 0.1 to 500, more preferably 0.3 to 100, and still more preferably 0.3 to 50.

Furthermore, in the aluminum silicate composite in the present invention, carbon is disposed on the surface of such an aluminum silicate, and the carbon disposed on the surface provides conductivity. Moreover, since aluminum silicate is an inorganic oxide, it is excellent in thermal stability and stability in a solvent.
Therefore, the conductive material for a lithium ion secondary battery of the present invention has the electrical characteristics and the life characteristics of a lithium ion secondary battery due to the ion exchange ability by Si and Al by the aluminum silicate complex and the conductivity by carbon. And improve together.

  In the present invention, unnecessary metal ions refer to nickel ions, manganese ions, cobalt ions, copper ions, iron ions and the like. These unnecessary metal ions are derived, for example, from impurity ions present in the constituent material of the lithium ion secondary battery or ions eluted from the positive electrode under high temperature.

<Aluminum silicate complex>
[Aluminum silicate]
The aluminum silicate in the present invention is an oxide salt containing aluminum and silicon. By using an oxide salt containing aluminum and silicon, the above-described ion exchange capacity can be exhibited. The aluminum silicate in the present invention is not particularly limited as long as it is an oxide salt containing aluminum and silicon, and may contain other metal elements. Examples of the aluminum silicate in the present invention include allophane, kaolin, zeolite, saponite, montmorillonite, attapulgite and imogolite.

  The volume-based average particle size of the aluminum silicate is preferably 0.1 μm to 100 μm according to the size of the final desired aluminum silicate complex, and is 0.5 μm to 50 μm. Is more preferable, and 1 μm to 30 μm is more preferable. The volume average particle size of aluminum silicate is measured using a laser diffraction method. The laser diffraction method can be performed using a laser diffraction type particle size distribution measuring apparatus (for example, SALD 3000J, manufactured by Shimadzu Corporation). Specifically, aluminum silicate is dispersed in a dispersion medium such as water to prepare a dispersion. With respect to this dispersion, when a volume cumulative distribution curve is drawn from the small diameter side using a laser diffraction type particle size distribution measuring device, a particle diameter (D50) which is 50% cumulative is determined as a volume average particle diameter.

The aluminum silicate preferably has a BET specific surface area of 250 m ² / g or more, and more preferably 280 m ² / g or more, from the viewpoint of improvement in metal ion adsorption capacity. When the BET specific surface area is 250 m ² / g or more, the amount of adsorption of unnecessary metal ions per unit mass is large, the efficiency is good, and a small amount of aluminum silicate tends to obtain a high effect.

Although the upper limit value of the BET specific surface area of aluminum silicate is not particularly limited, part of Si and Al in the aluminum silicate is bonded in the form of Si-O-Al, which improves the metal ion adsorption ability From the viewpoint of contributing to the above, the BET specific surface area is preferably 1500 m ² / g or less, more preferably 1200 m ² / g or less, and still more preferably 1000 m ² / g or less.

  The BET specific surface area of aluminum silicate is measured from the nitrogen adsorption capacity according to JIS Z 8830 (2001). As an evaluation device, a nitrogen adsorption measurement device (AUTOSORB-1, QUANTACHROME) or the like can be used. When measuring the BET specific surface area, it is considered that water adsorbed in the sample surface and structure has an influence on the gas adsorption ability, so first, pretreatment for water removal by heating is performed.

  In the pretreatment, the measurement cell into which 0.05 g of the measurement sample is charged is depressurized to 10 Pa or less with a vacuum pump, heated at 110 ° C., held for 3 hours or longer, and then kept at room temperature while maintaining the depressurized state. Allow to cool naturally (25 ° C). After this pretreatment, the evaluation temperature is set to 77 K, and the evaluation pressure range is measured as a relative pressure (equilibrium pressure to saturated vapor pressure) less than 1.

Aluminum silicates, from the viewpoint of improving the adsorption capacity of the metal ion is preferably the total pore volume is 0.1 cm ³ / g or more, more preferably 0.12 cm ³ / g or more, 0 More preferably, it is at least 15 cm ³ / g. In addition, the upper limit of the total pore volume is not particularly limited. From the viewpoint of suppressing the amount of adsorbed water in air per unit mass, the total pore volume is preferably 1.5 cm ² / g or less, more preferably 1.2 cm ² / g or less, and 1. More preferably, it is 0 cm ² / g or less.

  Based on the BET specific surface area, the total pore volume of the aluminum silicate is converted to the liquid by the amount of gas adsorbed closest to the relative pressure 1 among the data obtained in the relative pressure range of 0.95 or more and less than 1. Ask.

  From the viewpoint that the ion radius of unnecessary metal ions is 0.01 nm to 0.1 nm, the average pore diameter of the aluminum silicate is preferably 1.5 nm or more, and more preferably 2.0 nm or more. When the average pore diameter is in the above-mentioned range, unnecessary metal ions can be efficiently adsorbed even when unnecessary metal ions move to the adsorption site in the state accompanied by the ligand. Further, the upper limit value of the average pore diameter is not particularly limited. Since the specific surface area tends to increase as the average pore diameter decreases, the average pore diameter is preferably 50 nm or less, more preferably 20 nm or less, and still more preferably 5.0 nm or less. The average pore diameter of the aluminum silicate is determined based on the BET specific surface area and the total pore volume, assuming that all the pores are composed of one cylindrical pore.

  When using aluminum silicate as a raw material of a conductive material, it is preferable that the water content rate is 10 mass% or less, and it is more preferable that it is 5 mass% or less. When the water content is 10% by mass or less, the generation of gas that may occur when electrolysis occurs can be further suppressed, and the expansion of the battery can be further suppressed. The water content can be measured by the Karl Fischer method. As a method of setting the water content of aluminum silicate to 10% by mass or less, a heat treatment method which is usually used can be used without particular limitation. As a method of setting the water content of allophane to 10% by mass or less, for example, a method of heat-treating aluminum silicate at about 100 ° C. to 300 ° C. for about 6 hours to 24 hours under atmospheric pressure can be mentioned.

(Allophane)
The allophane in the present invention is an amorphous aluminum silicate having an element molar ratio Si / Al of silicon (Si) to aluminum (Al) of 0.1 to 1.0, and is a hollow sphere structure Means aluminum silicate which is said to form. As such allophane, for example, one having a composition represented by nSiO ₂ · Al ₂ O ₃ · mH ₂ O [n = 1 to 2, m = 2.5 to 3] can be mentioned.

  The element molar ratio Si / Al of allophane is preferably 0.2 to 1.0, and more preferably 0.5 to 1.0. By setting the element molar ratio Si / Al in this range, the ion exchange capacity described above is further enhanced. The element molar ratio Si / Al can be obtained by determining the atomic concentration of each of Si and Al by an ordinary method using ICP emission spectrometry (for example, ICP emission spectrometer: Hitachi Ltd., ICP emission spectrometer: P-4010). It is calculated from the atomic concentration. Hereinafter, the method of measuring the element molar ratio is the same.

  The allophane preferably has a water content of 10% by mass or less, more preferably 5% by mass or less. When the water content is 10% by mass or less, generation of gas that may occur when electrolysis occurs can be further suppressed, and expansion of the lithium ion secondary battery tends to be further suppressed. The water content can be measured by the Karl Fischer method. As a method of setting the water content of allophane to 10% by mass or less, a commonly used heat treatment method can be used without particular limitation. As a method of setting the water content of allophane to 10% by mass or less, for example, a method of heat treating allophane at about 100 ° C. to 300 ° C. for about 6 hours to 24 hours under atmospheric pressure can be mentioned.

  Allophane in the present invention may be a synthetic one, or a commercially available product may be purchased and used. A commercial product of Allophane includes, for example, product name Cecard (Shinagawa Chemical Co., Ltd.).

(Kaolin)
Kaolin in the present invention is an aluminum silicate having a layered structure and means an aluminum silicate formed from one or more of kaolinite, nacrite, dickite, halloysite, hydrohalite and the like. Such kaolin, for _example, include those having a composition represented by _{Al 2 SiO 5 · (H 2} O) 4 · nH 2 O [n = 0~5].

  The element molar ratio Si / Al of silicon (Si) to aluminum (Al) in kaolin is preferably 0.1 to 2.0, and more preferably 0.5 to 1.5. By setting the element molar ratio Si / Al in this range, the ion exchange capacity described above is further enhanced.

  The water content of kaolin is preferably 10% by mass or less, more preferably 5% by mass or less. When the water content is 10% by mass or less, the generation of gas that may occur when electrolysis occurs can be further suppressed, and the expansion of the lithium ion secondary battery can be further suppressed. The water content can be measured by the Karl Fischer method. As a method of setting the water content of kaolin to 10% by mass or less, a commonly used heat treatment method can be used without particular limitation. As a method of setting the water content of kaolin to 10% by mass or less, for example, a method of heat-treating kaolin at 100 ° C. to 300 ° C. for about 6 hours to 24 hours under atmospheric pressure may be mentioned.

  The kaolin in the present invention may be a synthetic one, or a commercially available product may be purchased and used. As a commercial item of kaolin, product name ASP-200 (Hayashi Kasei Co., Ltd.) etc. are mentioned.

(Zeolite)
The zeolite in the present invention is an aluminum silicate having an element molar ratio Si / Al of silicon (Si) to aluminum (Al) of 1 to 500, contains an alkali metal or an alkaline earth metal as a salt, It means the substance to be called. As such a zeolite, for example, metal cations such as X _{2 / n} O.Al ₂ O ₃ .ySiO ₂ .zH ₂ O [X = Na, K, Li, etc., n = valence of metal X, y = 2 What has a composition shown by -200, z = 0 or more] is mentioned.

  The element molar ratio Si / Al of the zeolite is preferably 1 to 100, and more preferably 1 to 50. By setting the element molar ratio Si / Al in this range, the ion exchange capacity described above is further enhanced.

  The zeolite preferably has a water content of 10% by mass or less, more preferably 5% by mass or less. When the water content is 10% by mass or less, the generation of gas that may occur when electrolysis occurs can be further suppressed, and the expansion of the lithium ion secondary battery can be further suppressed. The water content can be measured by the Karl Fischer method. As a method of setting the water content of the zeolite to 10% by mass or less, a heat treatment method which is usually used can be used without particular limitation. As a method of setting the water content of the zeolite to 10% by mass or less, for example, a method of heat-treating the zeolite at 100 ° C. to 300 ° C. for 6 hours to 24 hours under atmospheric pressure can be mentioned.

  The zeolite in the present invention may be a synthetic one, or a commercially available product may be purchased and used. Examples of commercially available products of zeolite include product name SP # 600 (Nitto Powder Chemical Industry Co., Ltd.), Molecular Sieves 4A (Wako Pure Chemical Industries, Ltd.), Molecular Sieves 13X (Wako Pure Chemical Industries, Ltd.), and the like.

(Saponite)
Saponite in the present invention means an aluminum silicate which is a layered clay compound of a smectite group (trioctahedral smectite) containing a metal cation such as Mg or Ca in the structure. As such a saponite, for example, X _0.33 (Mg ₃ ) (Al _0.33 Si _3.67 ) O ₁₀ (OH) ₂ · nH ₂ O [X = Mg, Ca, Na, K, Li, etc. And the metal cation of, n = 0 or more].

  The element molar ratio Si / Al of silicon (Si) to aluminum (Al) in saponite is preferably 2 to 50, and more preferably 5 to 30. By setting the element molar ratio Si / Al in this range, the ion exchange capacity described above is further enhanced.

  The water content of the saponite is preferably 10% by mass or less, more preferably 5% by mass or less. When the water content is 10% by mass or less, the generation of gas that may occur when electrolysis occurs can be further suppressed, and the expansion of the lithium ion secondary battery can be further suppressed. The water content can be measured by the Karl Fischer method. As a method of setting the water content of saponite to 10% by mass or less, a heat treatment method that is usually used can be used without particular limitation. As a method of setting the water content of saponite to 10% by mass or less, for example, a method of heat-treating saponite at 100 ° C. to 300 ° C. for about 6 hours to 24 hours under atmospheric pressure may be mentioned.

  The saponite in the present invention may be a synthetic one, or a commercially available product may be purchased and used. As a commercially available product of saponite, the product name smecton (Kunimine Kogyo Co., Ltd.) and the like can be mentioned.

(Montmorillonite Night)
Montmorillonite in the present invention means an aluminum silicate which is a layered clay compound of a smectite group (dioctahedral smectite) containing metal cations such as Mg and Ca in the structure. As such montmorillonite, for example, those having a composition represented by (Na, Ca) _0.33 (Al _1.67 , Mg _0.33 ) SiO ₄ O ₁₀ (OH) ₂ : nH ₂ O are listed. Be

  The element molar ratio Si / Al of silicon (Si) to aluminum (Al) in montmorillonite is preferably 2 to 50, and more preferably 5 to 30. By setting the element molar ratio Si / Al in this range, the ion exchange capacity described above is further enhanced.

  The water content of montmorillonite is preferably 10% by mass or less, more preferably 5% by mass or less. When the water content is 10% by mass or less, the generation of gas that may occur when electrolysis occurs can be further suppressed, and the expansion of the lithium ion secondary battery can be further suppressed. The water content can be measured by the Karl Fischer method. As a method of setting the water content of montmorillonite to 10% by mass or less, a heat treatment method which is usually used can be used without particular limitation. As a method of setting the water content of montmorillonite to 10% by mass or less, for example, a method of heat-treating montmorillonite at 100 ° C. to 300 ° C. for about 6 hours to 24 hours under atmospheric pressure may be mentioned.

  The montmorillonite in the present invention may be a synthetic one, or a commercially available product may be purchased and used. As a commercial item of montmorillonite, product name Kunipia (Kunimine Industrial Co., Ltd.) etc. are mentioned.

(Attapulgite)
Attapulgite in the present invention means an aluminum silicate having a fibrous crystal structure, also called palygorskite. As such attapulgite, for example, one having a composition represented by Mg (Al _0.5-1 Fe _0-0.5 ) Si ₄ O ₁₀ (OH) .4H ₂ O can be mentioned.

  The element molar ratio Si / Al of silicon (Si) to aluminum (Al) in attapulgite is preferably 2 to 50, and more preferably 5 to 30. By setting the element molar ratio Si / Al in this range, the ion exchange capacity described above is further enhanced.

  The water content of the attapulgite is preferably 10% by mass or less, more preferably 5% by mass or less. When the water content is 10% by mass or less, the generation of gas that may occur when electrolysis occurs can be further suppressed, and the expansion of the lithium ion secondary battery can be further suppressed. The water content can be measured by the Karl Fischer method. As a method of setting the water content of attapulgite to 10% by mass or less, a heat treatment method which is usually used can be used without particular limitation. As a method of setting the water content of attapulgite to 10% by mass or less, for example, a method of heat-treating attapulgite at 100 ° C. to 300 ° C. for about 6 hours to 24 hours under atmospheric pressure can be mentioned.

  The attapulgite in the present invention may be a synthetic one, or a commercially available product may be purchased and used. As a commercial product of attapulgite, product name ATAGEL (Hayashi Kasei Co., Ltd.) etc. are mentioned.

(Imogolite)
The imogolite in the present invention is an aluminum silicate having an element molar ratio Si / Al of silicon (Si) to aluminum (Al) of 0.3 to 1.0, and means other than the above. As such imogolite, for example, one having a composition represented by nSiO ₂ · Al ₂ O ₃ · mH ₂ O [n = 0.6 to 2.0, m = 0 or more] can be mentioned.

  In addition, from the viewpoint of the metal ion adsorption ability, as the imogolite, it is preferable that the element molar ratio Si / Al be 0.3 or more and less than 1.0. By setting the element molar ratio within this range, imogolite is superior in adsorption ability of unnecessary metal ions such as manganese ion, nickel ion, cobalt ion, copper ion, iron ion, etc., while having a lower adsorption ability to lithium ion Tend to be

  Further, by setting the element molar ratio Si / Al to 0.3 or more, it becomes easy to avoid that the amount of Al which does not contribute to the improvement of the metal ion adsorption ability becomes excessive, and the ion adsorption ability per unit mass is more It tends to be difficult to decrease. Further, by setting the element molar ratio Si / Al to less than 1.0, it becomes easy to avoid that the amount of Si not contributing to the improvement of the metal ion adsorption ability becomes excessive, and the ion adsorption ability per unit mass is further lowered. It tends to be difficult. Further, by setting the element molar ratio Si / Al to less than 1.0, it tends to be easier to avoid the decrease in the selectivity of the metal ion to be adsorbed. By using imogolite in this manner, it is possible to particularly selectively suppress the increase in the concentration of unnecessary metal ions in the lithium secondary battery.

  The element molar ratio Si / Al of imogolite is more preferably 0.4 to 0.6, and still more preferably 0.45 to 0.55. The above tendency is further enhanced by setting the imogolite to the element molar ratio Si / Al in this range.

The imogolite preferably has a peak at around 3 ppm in a ²⁷ Al-NMR spectrum. ^As a <27> Al-NMR measuring apparatus, a Bruker-Biospin company, AV400WB type | mold can be used, for example. The specific measurement conditions of < ²⁷ > Al-NMR are as follows.

Resonance frequency: 104 MHz
Measurement method: MAS (single pulse)
MAS rotation speed: 10 kHz
Measurement area: 52 kHz
Number of data points: 4096
resolution (measurement area / number of data points): 12.7 Hz
Pulse width: 3.0 μsec
Delay time: 2 seconds
Chemical shift value standard: 3.94 ppm of α-alumina
window function: Exponential function Line Broadening coefficient: 10 Hz

FIG. 1 shows a ²⁷ Al-NMR spectrum of imogolite according to Production Example 1 and Production Example 2 described later as an example of imogolite.

As shown in FIG. 1, imogolite preferably has a peak at around 3 ppm in a ²⁷ Al-NMR spectrum. The peak around 3 ppm is estimated to be a peak derived from six-coordinated Al. Furthermore, a peak may be present around 55 ppm. The peak around 55 ppm is estimated to be a peak derived from tetracoordinate Al.

Imogolite has a peak area ratio of around 55 ppm to a peak around 3 ppm (peak around 55 ppm / peak around 3 ppm) in the ²⁷ Al-NMR spectrum from the viewpoint of metal ion adsorption ability and metal ion selectivity. It is preferable that it is the following, It is more preferable that it is 20% or less, It is still more preferable that it is 15% or less.
Further, from the viewpoint of metal ion adsorption ability and metal ion selectivity, imogolite preferably has an area ratio of peak around 55 ppm with respect to a peak around 3 ppm in the ²⁷ Al-NMR spectrum preferably 1% or more, and 5% or more Is more preferably 10% or more.

The imogolite preferably has peaks at around -78 ppm and around -85 ppm in the ²⁹ Si-NMR spectrum. By being imogolite showing such a specific ²⁹ Si-NMR spectrum, the metal ion adsorption ability and the metal ion selectivity are further improved.

^As a <29> Si-NMR measurement apparatus, a Bruker-Biospin company, AV400WB type | mold can be used, for example. The specific measurement conditions of < ²⁹ > Si-NMR are as follows.

Resonant frequency: 79.5 MHz
Measurement method: MAS (single pulse)
MAS speed: 6 kHz
Measurement area: 24 kHz
Number of data points: 2048
resolution (measurement area / number of data points): 5.8 Hz
Pulse width: 4.7 μsec
Delay time: 600 sec
Chemical shift value criteria: _TMSP-d 4 (3- (trimethylsilyl) (2,2,3,3- ² H ₄₎ propionate) 1.52Ppm the
window function: Exponential function Line Broadening coefficient: 50 Hz

The ²⁹ Si-NMR spectrum of the imogolite which concerns on the below-mentioned manufacture example 1 and the manufacture example 2 as an example of imogolite in FIG. 2 is shown.

As shown in FIG. 2, it is preferable that imogolite has peaks in the vicinity of −78 ppm and in the vicinity of −85 ppm in the ²⁹ Si-NMR spectrum. The peak A appearing around −78 ppm is derived from an aluminum silicate having a crystal structure such as imogolite and allophane, and is considered to be derived from a structure of HO—Si— (OAl) ₃ .
Moreover, peak B appearing near -85 ppm is considered to be aluminum silicate having a clay structure or aluminum silicate having an amorphous structure. Therefore, imogolite having peaks at around -78 ppm and around -85 ppm is estimated to be a mixture or a complex of imogolite having a crystalline structure and imogolite having a clay structure or an amorphous structure.

  In particular, imogolite having a peak A appearing around -78 ppm has a large amount of OH groups per unit mass. Imogolite, which has a peak A appearing around -78 ppm, is excellent in ion adsorption ability in addition to excellent in water adsorption ability, and in particular, selectivity in adsorption of unnecessary metal ions adversely affecting lithium ion secondary batteries Noticeably high. For this reason, in a lithium ion secondary battery containing a conductive material for a lithium ion secondary battery including this imogolite, the occurrence of a short circuit with time is further suppressed, and as a result, a lithium ion secondary battery with more excellent life characteristics is provided. Can be thought of as

  In addition, imogolite does not need to have a peak around -85 ppm originating in a layered clay mineral. Here, having no peak means that the displacement from the baseline at around -85 ppm is equal to or less than the noise level, specifically, the displacement from the baseline is 100% or less of the noise width. means.

Imogolite has an area ratio (peak B / peak A) of peak A in the vicinity of −78 ppm and peak B in the vicinity of −85 ppm in the ²⁹ Si-NMR spectrum, from the viewpoint of improving metal ion adsorption ability and metal ion selectivity. It is preferable that it is 0.4-9.0, It is more preferable that it is 1.5-9.0, It is still more preferable that it is 2.0-9.0, It is 2.0-7.0 Very particularly preferably 2.0 to 5.0, and most preferably 2.0 to 4.0.

When obtaining the area ratio of the peaks in ²⁹ Si-NMR spectrum, subtract baseline in first ²⁹ Si-NMR spectra. In FIG. 2, a straight line connecting −55 ppm and −140 ppm is used as a baseline.

Next, the curve of the ²⁹ Si-NMR spectrum is separated by a chemical shift value (around -81 ppm in FIG. 2) corresponding to a valley between a peak appearing around -78 ppm and a peak appearing around -85 ppm.

The area of peak A in the vicinity of -78 ppm is the area of the region surrounded by the straight line passing through -81 ppm orthogonal to the chemical shift axis, the above baseline, and the curve of the ²⁹ Si-NMR spectrum in FIG. The area of peak B near -85 ppm is the area of the region enclosed by the straight line perpendicular to the chemical shift axis and passing -81 ppm, the above baseline, and the curve of the ²⁹ Si-NMR spectrum.
The area of each peak may be determined by analysis software incorporated in an NMR measurement apparatus.

  Imogolite preferably has peaks in the vicinity of 2θ = 26.9 ° and 40.3 ° in a powder X-ray diffraction spectrum using CuKα radiation as an X-ray source. For example, Rigaku Corporation Geigerflex RAD-2X (product name) can be used as an X-ray-diffraction apparatus.

The powder X-ray-diffraction spectrum of the imogolite which concerns on the below-mentioned manufacture example 1 and the manufacture example 2 as an example of imogolite in FIG. 3 is shown.
As shown in FIG. 3, imogolite has peaks at 2θ = 26.9 ° and 40.3 ° in the powder X-ray diffraction spectrum. The peaks around 2θ = 26.9 ° and 40.3 ° are estimated to be those derived from imogolite.

Imogolite may not have broad peaks near 2θ = 20 ° and 35 ° in the powder X-ray diffraction spectrum. The peaks around 2θ = 20 ° and 35 ° are considered to be peaks due to the reflection of the hk0 face of the low crystalline layered clay mineral.
Here, not having peaks at 2θ = 20 ° and 35 ° means that the displacement from the baseline at around 2θ = 20 ° and 35 ° is equal to or less than the noise level, specifically, the baseline Means that the displacement from is less than 100% of the noise width.

  Furthermore, like imogolite according to Preparation Example 1, imogolite may have peaks at 2θ = 18.8 °, 20.3 °, 27.8 °, 40.6 °, and 53.3 °. . The peaks around 2θ = 18.8 °, 20.3 °, 27.8 °, 40.6 ° and 53.3 ° are estimated to be peaks derived from by-product aluminum hydroxide. In the imogolite manufacturing method described later, precipitation of aluminum hydroxide can be further suppressed by setting the temperature at the heat treatment to 160 ° C. or less. Moreover, content of aluminum hydroxide can be adjusted by adjusting pH at the time of the desalting process by centrifugation.

  Moreover, like imogolite which concerns on manufacture example 2, imogolite may have a peak in 2 (theta) = 4.8 degrees, 9.7 degrees, and 14.0 degrees vicinity. Furthermore, it may have a peak around 2θ = 18.3 °. The peaks around 2θ = 4.8 °, 9.7 °, 14.0 ° and 18.3 ° are derived from the fact that single fibers of tubular imogolite aggregate along each other to form a bundle-like structure It is estimated to be a peak.

  4 and 5 show an example of a transmission electron microscope (TEM) photograph of imogolite. Imogolite shown in FIG. 4 is imogolite according to Production Example 1 described later. Imogolite shown in FIG. 5 is imogolite according to Production Example 2 described later.

As shown in FIG. 4, in the imogolite according to Production Example 1, when observed at 100,000 magnifications in a transmission electron microscope (TEM), no tubular member having a length of 50 nm or more is present. The imogolite according to Production Example 2 is a tubular so-called imogolite as shown in FIG.
From the viewpoint of metal ion adsorption ability and metal ion selectivity, it is preferable that imogolite has no tubular member having a length of 50 nm or more when observed at 100,000 times in a transmission electron microscope (TEM). .

  The observation of the imogolite transmission electron microscope (TEM) is performed at an acceleration voltage of 100 kV. Further, as an observation sample, the solution after heating before the second washing step (desalting and solid separation) in the manufacturing method described later is dropped onto a support for preparing a TEM observation sample, and then the solution after heating is dropped. Use dried thin film. In addition, when the contrast of the TEM image can not be obtained sufficiently, an observation sample is prepared using a properly diluted solution after heating so that the contrast can be sufficiently obtained.

  The tubular material as shown in FIG. 5 is manufactured by performing heat treatment when the silicate ion and the aluminum ion are below a specific concentration in the method of manufacturing imogolite described later. On the other hand, imogolite, in which no tubular as shown in FIG. 4 is observed, is produced by performing heat treatment when the concentration of silicate ions and aluminum ions is above a specific concentration.

  FIG. 6 is a drawing schematically showing tubular imogolite which is an example of imogolite. As shown in FIG. 6, this imogolite 10 has a structure in which a plurality of (three in FIG. 6) tubulars 10a are assembled. A gap 30 defined by the outer wall of the tubular member 10a is formed between the plurality of tubular members 10a. The imogolite 10 tends to form a fiber structure by the tubular members 10a, and the outer wall of the tubular member 10a forming the gap 30 between the inner wall 20 in the tubular member of the tubular member 10a and the plurality of tubular members 10a Surface) can be used as an adsorption site for metal ions. The length of the tubular portion 10 a in the tube length direction is, for example, 10 nm to 10 μm. The tubular member 10a has, for example, a circular tubular shape, and the outer diameter is, for example, 1.5 nm to 3.0 nm, and the inner diameter is, for example, 0.7 nm to 1.4 nm.

In the case where fibers of imogolite tubular is observed with a transmission electron microscope (TEM) photograph, in ^{29 Si-NMR} spectrum, there is a tendency that the area of the peak B is small.

The imogolite preferably has a BET specific surface area of 250 m ² / g or more, and more preferably 280 m ² / g or more, from the viewpoint of improving metal ion adsorption capacity. When the BET specific surface area is 250 m ² / g or more, the amount of adsorption of unnecessary metal ions per unit mass is large, so that the efficiency is good, and a higher effect tends to be obtained with a small amount of imogolite.

Further, the upper limit value of the BET specific surface area is not particularly limited, but from the viewpoint that Si and Al in imogolite are partially bound in the form of Si-O-Al, which contributes to the improvement of metal ion adsorption ability. The BET specific surface area is preferably 1500 m ² / g or less, more preferably 1200 m ² / g or less, and still more preferably 1000 m ² / g or less.

  The BET specific surface area of imogolite is measured from the nitrogen adsorption capacity according to JIS Z 8830 (2001). As an evaluation device, a nitrogen adsorption measurement device (AUTOSORB-1, QUANTACHROME) or the like can be used. When measuring the BET specific surface area, it is considered that water adsorbed in the sample surface and structure has an influence on the gas adsorption ability, so first, pretreatment for water removal by heating is performed.

  In the pretreatment, the measurement cell into which 0.05 g of the measurement sample is charged is depressurized to 10 Pa or less with a vacuum pump, heated at 110 ° C., held for 3 hours or longer, and then kept at room temperature while maintaining the depressurized state. Allow to cool naturally (25 ° C). After this pretreatment, the evaluation temperature is set to 77 K, and the evaluation pressure range is measured as a relative pressure (equilibrium pressure to saturated vapor pressure) less than 1.

Imogolite preferably has a total pore volume of 0.10 cm ³ / g or more, more preferably 0.12 cm ³ / g or more, and more preferably 0.15 cm ³ , from the viewpoint of improving the adsorption ability of metal ions. It is more preferable that it is / g or more. In addition, the upper limit of the total pore volume is not particularly limited. From the viewpoint of suppressing the amount of adsorbed water in air per unit mass, the total pore volume is preferably 1.5 cm ³ / g or less, more preferably 1.2 cm ³ / g or less, and 1. More preferably, it is 0 cm ³ / g or less.

  The total pore volume of the imogolite is obtained by converting the gas adsorption amount closest to the relative pressure 1 into liquid among the data obtained in the relative pressure range of 0.95 or more and less than 1 based on the BET specific surface area.

  From the viewpoint that the ion radius of unnecessary metal ions is 0.01 nm to 0.1 nm, the average pore diameter of imogolite is preferably 1.5 nm or more, and more preferably 2.0 nm or more. If the average pore diameter is in the above-mentioned range, the unnecessary metal ions tend to be able to be efficiently adsorbed even when the unnecessary metal ions move to the adsorption site with the ligand. In addition, the upper limit of the average pore diameter is not particularly limited, and the specific surface area tends to increase when the average pore diameter decreases, so the average pore diameter is preferably 50 nm or less, and more preferably 20 nm or less. More preferably, it is 5.0 nm or less. The average pore diameter of imogolite is determined based on the BET specific surface area and the total pore volume, assuming that all the pores are composed of one cylindrical pore.

  The water content of imogolite is preferably 10% by mass or less, more preferably 5% by mass or less. When the water content is 10% by mass or less, generation of gas that may occur when electrolysis occurs can be further suppressed, and expansion of the lithium ion secondary battery tends to be further suppressed. The water content can be measured by the Karl Fischer method.

  As a method of setting the water content of imogolite to 10% by mass or less, a heat treatment method which is usually used can be used without particular limitation. As a method of setting the water content of imogolite to 10% by mass or less, for example, a method of heat treating imogolite at about 100 ° C. to 300 ° C. for about 6 hours to 24 hours under atmospheric pressure may be mentioned.

The imogolite in the present invention may be synthesized or a commercially available product may be purchased and used.
When imogolite is synthesized, the method of producing imogolite according to the present invention comprises the steps of mixing a solution containing a silicate ion and a solution containing an aluminum ion to obtain a reaction product, the reaction product as an acid in an aqueous medium, Heat-treating in the presence of and, if necessary, may have other steps. From the viewpoint of the yield of the obtained imogolite, formation of a structure, etc., it is preferable to have a washing step of performing desalting and solid separation, preferably before and after the heat treatment step, at least after the heat treatment step.
After desalting coexistence ions from a solution containing imogolite which is a reaction product, heat treatment in the presence of an acid tends to enable efficient production of imogolite having excellent metal ion adsorption ability. Here, examples of the coexisting ions include sodium ion, chloride ion, perchlorate ion, nitrate ion, sulfate ion and the like.
This can be considered, for example, as follows. By heat treating imogolite from which coexisting ions that inhibit formation of a regular structure are removed in the presence of an acid, imogolite having a regular structure is formed. By having an ordered structure, it can be considered that the affinity to metal ions is improved and metal ions can be efficiently adsorbed.

  It is more preferable that the method for producing imogolite includes steps of desalting and solid separation before and after the heat treatment step. That is, an example of a preferred method for producing imogolite comprises the steps of: (a) mixing a solution containing a silicate ion and a solution containing an aluminum ion to obtain a reaction product; (b) desalting the reaction product; Solid separation step (first washing step), (c) heat treatment of the solid separated in the step (b) in an aqueous medium in the presence of an acid (synthesis step), (d) the step (C) a step of desalting and solid separation (a second washing step) of the product obtained by the heat treatment in (c), and, if necessary, another method. Hereinafter, a method of producing imogolite will be described according to this preferred method of production.

(A) Step of obtaining a reaction product In the step of obtaining a reaction product, a solution containing silicate ion and a solution containing aluminum ion are mixed to obtain a mixed solution containing a reaction product containing imogolite and coexistent ions. Get

(A-1) Silicate ion and aluminum ion When producing imogolite, silicate ion and aluminum ion are required as raw materials. As a silicic acid source which comprises the solution (henceforth a "silicic acid solution") containing a silicate ion, it will not restrict | limit, especially if it will produce a silicate ion when it solvates. Examples of the silicic acid source include, but are not limited to, tetraalkoxysilanes such as sodium orthosilicate, sodium metasilicate and tetraethoxysilane.
Moreover, the aluminum source which comprises the solution (Hereafter, it is also called "aluminum solution") containing aluminum ion will not be restrict | limited especially if it produces | generates an aluminum ion when it solvates. The aluminum source includes, but is not limited to, aluminum chloride, aluminum perchlorate, aluminum nitrate, aluminum sulfate, aluminum sec-butoxide and the like.

  As the solvent, a solvent which is easily solvated with the raw material silicic acid source and aluminum source can be appropriately selected and used. Specifically, water, ethanol or the like can be used as the solvent. It is preferable to use water as the solvent from the viewpoint of reduction of coexisting ions in the solution at the time of heat treatment and ease of handling.

(A-2) Mixing ratio and solution concentration These raw materials are respectively dissolved in a solvent to prepare a raw material solution (a silicic acid solution and an aluminum solution), and then the raw material solutions are mixed with each other to obtain a mixed solution. At this time, in order to obtain imogolite having a specific element molar ratio Si / Al, the elemental molar ratio Si / Al of Si and Al in the mixed solution is set to the element molar ratio Si / Al of Si and Al in the obtained imogolite It may be adjusted to be 0.3 to 1.0, preferably 0.3 to less than 1.0, and more preferably 0.4 to 0. It is adjusted to be 6 and more preferably adjusted to be 0.45 to 0.55. By setting the element molar ratio Si / Al to 0.3 to 1.0, it becomes easy to synthesize imogolite having a desired regular structure.

  In addition, when mixing the raw material solutions, it is preferable to gradually add the silicic acid solution to the aluminum solution. In this way, the polymerization of silicic acid, which can be a factor that inhibits the formation of the desired imogolite, can be further suppressed.

The silicon atom concentration in the silicic acid solution is not particularly limited, and is preferably 1 mmol / L to 1000 mmol / L.
When the silicon atom concentration of the silicic acid solution is 1 mmol / L or more, the productivity is further improved, and the desired imogolite can be efficiently produced. When the silicon atom concentration is 1000 mmol / L or less, the productivity is further improved according to the silicon atom concentration.

The aluminum atom concentration of the aluminum solution is not particularly limited, and is preferably 100 mmol / L to 1000 mmol / L.
When the aluminum atom concentration of the aluminum solution is 100 mmol / L or more, productivity is further improved, and imogolite can be efficiently produced. When the aluminum atom concentration is 1000 mmol / L or less, the productivity is further improved according to the aluminum atom concentration.

(B) First washing step (desalting and solid separation)
A solution containing silicate ions and a solution containing aluminum ions are mixed, and imogolite containing coexistent ions is produced as a reaction product in the resulting mixed solution, and then the imogolite containing the coexistent ions is desalted and The first washing step of solid separation is performed. In the first washing step, at least a part of the coexisting ions is removed from the mixed solution to reduce the coexisting ion concentration in the mixed solution. By performing the first washing step, it becomes easy to form desired imogolite in the synthesis step.

  In the first washing step, the method for desalting and solid separation is an anion other than the silicate ion derived from the silicic acid source and the aluminum source (chloride ion, nitrate ion etc.) and a cation other than the aluminum ion (sodium ion etc.) The solid separation may be performed by removing (desalting) at least a part of Examples of the first washing step include a method using centrifugation, a method using a dialysis membrane, and a method using an ion exchange resin.

The first washing step is preferably performed such that the concentration of coexisting ions in the mixed solution is equal to or less than a predetermined concentration. Here, the concentration of the coexisting ions may be, for example, 500 mmol / L or less when the solid separated product obtained in the first washing step is dispersed in pure water so that the concentration is 60 g / L. preferable. In order to achieve such coexistence ion concentration, for example, when the solid separated product obtained in the first washing step is dispersed in pure water so as to have a concentration of 60 g / L, the electric power of the dispersion is obtained. Washing is preferably carried out so that the conductivity is 4.0 S / m or less, more preferably 1.0 mS / m to 3.0 S / m, 1.0 mS / m to 2 More preferably, the washing is carried out so as to have a density of 0.1 S / m.
When the electrical conductivity of the dispersion is 4.0 S / m or less, the desired aluminum silicate tends to be more easily formed in the synthesis process.
In addition, an electrical conductivity is measured at normal temperature (25 degreeC) using Horiba, Ltd .: F-55 and its common electrical conductivity cell: 9382-10D.

The first washing step preferably includes the steps of dispersing imogolite in a solvent to obtain a dispersion, adjusting the pH of the dispersion to 5 to 8, and precipitating imogolite.
For example, when the first washing step is performed using centrifugation, it can be performed as follows. The pH is adjusted to 5 to 8 by adding alkali or the like to the dispersion. After centrifuging the dispersion after adjusting the pH, the supernatant solution is drained and the solid is separated as a gel-like precipitate. The solid separated is redispersed in a solvent. At that time, it is preferable to return the volume of the dispersion to the volume before centrifugation using, for example, a solvent. The concentration of coexisting ions can be reduced to a predetermined concentration or less by repeating the operation of similarly centrifuging the redispersed dispersion and desalting and solid separation.

  In the first washing step, the pH of the dispersion is adjusted to, for example, 5-8. The pH of the dispersion is preferably 5.5 to 6.8, and more preferably 5.8 to 6.5. The alkali used for pH adjustment is not particularly limited. As an alkali used for adjustment of pH, sodium hydroxide and ammonia are preferable, for example.

The conditions for centrifugation are appropriately selected according to, for example, the production scale, the type of container used, and the size of the container used. The conditions for centrifugation may be, for example, 1200 G or more and 1 minute to 30 minutes at room temperature (25 ° C.). Specifically, as conditions for centrifugation, for example, when using Tomy Seiko Co., Ltd .: Suprema 23 as a centrifugal separator and Standard Rotor NA-16 manufactured by the same company, 3000 min ⁻¹ (rotation / hour at room temperature (25 ° C.) Minutes) (1450 G) or more can be 5 minutes to 10 minutes.

  As the solvent in the first washing step, a solvent which is easily solvated with the raw material can be appropriately selected and used, and specifically, water, ethanol or the like can be used as the solvent. It is preferable to use water as the solvent from the viewpoint of reduction of coexisting ions in the solution in the synthesis step and easiness of handling, and it is more preferable to use pure water. When the washing is repeated several times, it is preferable to omit the adjustment of the pH of the mixed solution.

  The number of times of desalting and solid separation processing in the first washing step may be appropriately set according to the remaining amount of coexistent ions. For example, the number of times of processing can be 1 to 6 times. When the washing is repeated about three times, the remaining amount of coexisting ions is reduced to such an extent that the desired synthesis of imogolite is not affected.

  The pH measurement at the time of adjusting pH can be measured by a pH meter using a common glass electrode. Specifically, for example, product name: MODEL (F-51) of Horiba, Ltd. can be used.

(C) Synthesis step In the synthesis step, the heat treatment of the solid separated matter obtained in the first washing step is performed in the presence of an acid in an aqueous medium.
Forming a desired imogolite having a regular structure by heat treating a solution (dispersion liquid) obtained by the first washing step and containing imogolite having a reduced concentration of coexistent ions in the presence of an acid Can.

In the synthesis step, the solid separated material obtained in the first washing step may be appropriately diluted to perform synthesis as a dilute solution, or the solid separated material obtained in the first washing step may be synthesized as a high concentration solution May be
By performing the synthesis step in a dilute solution, it is possible to obtain imogolite (hereinafter also referred to as "first imogolite") having a regular structure that is tubularly elongated. Further, by performing the synthesis step in a high concentration solution, it is possible to obtain imogolite having a clay structure and an amorphous structure (hereinafter, also referred to as “second imogolite”) in addition to the regular structure. The second imogolite is presumed to have increased formation of a clay structure and an amorphous structure instead of growing into a tubular having a length of 50 nm or more.
Both the first and second imogolites exhibit excellent metal ion adsorption ability by having a specific regular structure.

As a dilution condition of the solution for obtaining the first imogolite in the synthesis step, for example, the silicon atom concentration can be 20 mmol / L or less and the aluminum atom concentration can be 60 mmol / L or less. Among them, from the viewpoint of metal ion adsorption ability, as dilution conditions, it is preferable that silicon atom concentration is 0.1 mmol / L to 10 mmol / L and aluminum atom concentration is 0.1 mmol / L to 34 mmol / L, and silicon atom concentration Is more preferably 0.1 mmol / L to 2 mmol / L and the aluminum atom concentration is 0.1 mmol / L to 7 mmol / L.
By setting the silicon atom concentration to 20 mmol / L or less and the aluminum atom concentration to 60 mmol / L or less as the dilution conditions, it is possible to more efficiently produce the first imogolite.
In addition, in the synthesis of the first imogolite, the reaction may be difficult to proceed because the reaction is performed with a dilute solution, and the Si / Al ratio of the preparation amount may be different from the Si / Al ratio of the obtained imogolite. In such a case, imogolite having a desired Si / Al ratio tends to be obtained by charging the silicon atomic weight of the raw material to a smaller amount than the desired ratio.

In addition, as a concentration condition of the solution for obtaining the second imogolite in the synthesis step, for example, the silicon atom concentration can be 100 mmol / L or more and the aluminum atom concentration can be 100 mmol / L or more. Among them, from the viewpoint of metal ion adsorption ability, as concentration conditions, silicon atom concentration is preferably 120 mmol / L to 2000 mmol / L and aluminum atom concentration is preferably 120 mmol / L to 2000 mmol / L, and silicon atom concentration is 150 mmol / L It is more preferable that it is -1500 mmol / L and an aluminum atom concentration is 150 mmol / L-1500 mmol / L.
By setting the silicon atom concentration to 100 mmol / L or more and the aluminum atom concentration to 100 mmol / L or more as the concentration conditions, the second imogolite can be produced more efficiently, and the productivity of the aluminum silicate is further increased. It tends to improve.

The silicon atom concentration and the aluminum atom concentration are the silicon atom concentration and the aluminum atom concentration in the solution after adjusting the pH to a predetermined range by adding an acidic compound described later.
In addition, the silicon atom concentration and the aluminum atom concentration are measured by an ordinary method using an ICP emission spectrometer (for example, ICP emission spectrometer: Hitachi, Ltd., P-4010).

  When adjusting the silicon atom concentration and the aluminum atom concentration to a predetermined concentration, a solvent may be added to the solution. As the solvent, those easily solvated with the raw materials can be appropriately selected and used. Specifically, water, ethanol, etc. can be used as the solvent, and it is preferable to use water from the viewpoint of reduction of coexistent ions in the solution at the time of heat treatment and ease of handling, and use pure water. Is more preferred.

  In the synthesis step, at least one of the acidic compounds is added to the solution prior to the heat treatment. The pH of the solution after addition of the acidic compound is not particularly limited. From the viewpoint of obtaining desired imogolite efficiently, the solution preferably has a pH of 3 or more and less than 7, and more preferably 3 to 5.

  The acidic compound to be added in the synthesis step is not particularly limited, and may be an organic acid or an inorganic acid. Among them, it is preferable to use an inorganic acid. Specific examples of the inorganic acid include hydrochloric acid, perchloric acid and nitric acid. In consideration of the reduction of coexisting ion species in the solution in the subsequent heat treatment, it is preferable to use an acidic compound that produces an anion similar to the anion contained in the used aluminum source.

By adding an acidic compound to the solution and performing heat treatment, imogolite having a desired structure can be obtained.
The temperature of the heat treatment is not particularly limited. From the viewpoint of obtaining desired imogolite efficiently, the temperature of the heat treatment is preferably 80 ° C to 160 ° C.
When the temperature of the heat treatment is 160 ° C. or less, precipitation of boehmite (aluminum hydroxide) tends to be further suppressed. When the temperature of the heat treatment is 80 ° C. or higher, the synthesis rate of the desired aluminum silicate tends to be improved, and the desired imogolite tends to be able to be produced more efficiently.

  The time of the heat treatment is not particularly limited. When imogolite having a desired structure is more efficiently obtained, the heat treatment time is preferably within 96 hours (4 days). When the heat treatment time is 96 hours or less, the desired imogolite tends to be able to be produced more efficiently.

(D) Second washing step (desalting and solid separation)
The product obtained by heat treatment in the synthesis step is subjected to desalting and solid separation in the second washing step. This tends to make it possible to obtain imogolite having excellent metal ion adsorption ability. This can be considered, for example, as follows. That is, in the product obtained by heat treatment in the synthesis step, the imogolite adsorption site may be blocked by the coexistent ions, and the metal ion adsorption capacity as expected may not be obtained. Therefore, it is desirable to have excellent metal ion adsorption ability by performing a second washing step of removing at least a part of coexisting ions from imogolite as a product obtained in the synthesis step by desalting and solid separation. It can be considered that imogolite can be obtained.

In the second washing step, at least a part of the anion other than the silicate ion and the cation other than the aluminum ion may be removed by the washing (desalting and solid separation) treatment. The washing process applied in the second washing step may be the same as or different from the first washing step before the synthesis step.
The second washing step is preferably performed such that the concentration of the coexisting ions is equal to or less than a predetermined concentration. Here, the concentration of the coexisting ions may be, for example, 500 mmol / L or less when the solid separated in the second washing step is dispersed in pure water so as to have a concentration of 60 g / L. it can. Specifically, for example, when the solid separated product obtained in the second washing step is dispersed in pure water so as to have a concentration of 60 g / L, such coexistence ion concentration can be obtained. The washing is preferably carried out so that the electric conductivity of the dispersion is 4.0 S / m or less, more preferably 1.0 mS / m to 3.0 S / m, more preferably 1.0 mS. It is further preferable to perform washing so as to be / m to 2.0 S / m.
When the electric conductivity of the dispersion is 4.0 S / m or less, there is a tendency that an imogolite having more excellent metal ion adsorption ability can be easily obtained.

  When performing a 2nd washing process using centrifugation, it can carry out as follows, for example. A solvent is added to the product obtained after the heat treatment to obtain a mixed solution. The pH is adjusted to 5 to 10 by adding alkali or the like to the mixed solution. After centrifuging the pH-adjusted mixed solution, the supernatant solution is drained and the solid is separated as a gel-like precipitate. The solid separated is then redispersed in the solvent. At that time, it is preferable to return the volume of the dispersion to the same volume as that before centrifugation. The concentration of the coexisting ions can be reduced to a predetermined concentration or less, for example, 3% by mass or less by repeating the operations of similarly centrifuging the redispersed dispersion to desalt and separate the solid.

  In the second washing step, the pH of the mixed solution is preferably adjusted to, for example, 5 to 10, and more preferably to 8 to 10. The alkali used for adjusting the pH is not particularly limited. The alkali used to adjust the pH preferably includes sodium hydroxide and ammonia.

The conditions for centrifugation are appropriately selected according to, for example, the production scale, the type of container to be used, and the size of the container to be used. The conditions for centrifugation may be, for example, 1200 G or more and 1 minute to 30 minutes at room temperature (25 ° C.). As the conditions for centrifugation, specifically, for example, when using Tomy Seiko Co., Ltd .: Suprema 23 as a centrifugal separator and its standard rotor NA-16, 3000 min ⁻¹ (rotation / minute at room temperature (25 ° C.) ) (1450 G) or higher can be 5 minutes to 10 minutes.

  As the solvent in the second washing step, one which can be easily solvated with the product after heat treatment can be appropriately selected and used, and specifically, water, ethanol or the like can be used as the solvent . As the solvent, water is preferably used, and pure water is more preferably used, from the viewpoint of reduction of coexisting ions and ease of handling. When the washing is repeated several times, it is preferable to omit the adjustment of the pH of the mixed solution.

  The number of times of desalting and solid separation in the second washing step may be set according to the remaining amount of coexisting ions. The number of desalting and solid separation processes is preferably once to six times, and more preferably about three times. If the washing is repeated about three times, the residual amount of coexisting ions in imogolite tends to be sufficiently reduced.

In the dispersion after the second washing step, among the remaining coexisting ions, it is preferable that the concentrations of chloride ion and sodium ion which particularly affect the adsorptivity of imogolite be reduced. That is, when the imogolite after the washing in the second washing step disperses the imogolite in water to prepare an aqueous dispersion having a concentration of 400 mg / L, the chloride ion concentration is 100 mg / L or less and the sodium ion in the aqueous dispersion. It is preferable that the concentration be 100 mg / L or less. When the chloride ion concentration is 100 mg / L or less and the sodium ion concentration is 100 mg / L or less, the imogolite adsorption capacity can be further improved. The chloride ion concentration is more preferably 50 mg / L or less, still more preferably 10 mg / L or less. The sodium ion concentration is more preferably 50 mg / L or less, still more preferably 10 mg / L or less. The chloride ion concentration and the sodium ion concentration can be adjusted according to the number of treatments in the washing step or the type of alkali used to adjust the pH.
The chloride ion concentration and the sodium ion concentration are measured by ion chromatography (for example, Nippon Dionex Co., Ltd., DX-320 and DX-100) under ordinary conditions.
The concentration of the imogolite dispersion is based on the mass of the solid obtained by drying the solid separated at 110 ° C. for 24 hours.

  The term "dispersion after the second washing step" as used herein means a dispersion obtained by adding a solvent after completion of the second washing step and returning it to the same volume as the volume before the second washing step. Do. The solvent to be used can be appropriately selected and used from those easily solvated with the raw material, and specifically, water, ethanol or the like can be used, but the residual amount of coexisting ions in imogolite is reduced, and For ease of handling, it is preferable to use water, and it is more preferable to use pure water.

  The BET specific surface area of imogolite is determined by the treatment conditions of the second washing step (for example, after adding an alkali to the synthesis solution to adjust the pH to 5 to 10, centrifuging and discharging the supernatant solution, it remains as a gel-like precipitate The imogolite can be redispersed in a solvent, and the conditions of the method of repeating the process of returning to the same volume as the volume before centrifugation one or more times can be adjusted.

  In addition, the total pore volume of imogolite is treated under the conditions of the second washing step (for example, alkali is added to the synthesis solution to adjust the pH to 5 to 10, centrifuged, and then the supernatant solution is discharged to form a gel-like precipitate The remaining imogolite can be re-dispersed in a solvent, and the conditions of the method of repeating the process of returning to the same volume as the volume before centrifugation one or more times can be adjusted.

  In addition, the average pore diameter of imogolite is determined according to the processing conditions of the second washing step (for example, after adding alkali to the synthesis solution to adjust the pH to 5 to 10, centrifuging and discharging the supernatant solution, gelled precipitate The remaining imogolite can be re-dispersed in a solvent, and the conditions of the method of repeating the process of returning to the same volume as the volume before centrifugation one or more times can be adjusted.

  The solid separated material (precipitate containing imogolite) obtained in the second washing step (d) is heat-treated and dried to obtain imogolite powder. The heat treatment temperature is preferably 30 ° C. to 180 ° C., more preferably 40 ° C. to 150 ° C., and still more preferably 50 ° C. to 120 ° C.

[Carbon coating]
In the aluminum silicate composite according to the present invention, carbon is disposed on the surface of the aluminum silicate. The carbon to be disposed is disposed on at least a part or all of the surface of the aluminum silicate complex.

Carbon may be disposed on the surface of aluminum silicate. 7 to 11 are schematic cross-sectional views showing an example of the configuration of the aluminum silicate composite according to the present invention.
In FIG. 7, carbon 40 covers the entire surface of aluminum silicate 50. In FIG. 8, carbon 40 covers the entire surface of aluminum silicate 50, but the thickness of carbon 40 varies. Also, in FIG. 9, carbon 40 is partially present on the surface of aluminum silicate 50, and the surface of aluminum silicate 50 has a portion not covered with carbon 40. In FIG. 10, on the surface of aluminum silicate 50, particles of carbon 40 having a particle size smaller than that of aluminum silicate 50 are present. FIG. 11 is a modification of FIG. 10, and the particle shape of carbon 40 is scaly. In FIGS. 7 to 11, the shape of the aluminum silicate 50 is schematically represented by a spherical shape (circle as a cross sectional shape), but the shape is spherical, block shape, scaly shape, or polygonal in cross sectional shape. It may be any shape (shape with corners) or the like.

In addition, when aluminum silicate is comprised by several tubulars, carbon should just be arrange | positioned microscopically in at least one part or all part of the outer wall of a tubular thing, and at least one part or all of the inner wall Carbon may be arranged.
Also, in the case where fine aluminum silicates are aggregated, bound or aggregated to form particles, carbon may be disposed on at least a part or all of the particle surface, and the inside of the particles may be formed by aggregation, binding or aggregation. When there are pores in the carbon, carbon may be disposed in part or all of the pores.

Inside of aluminum silicate (In the case where the inner wall of a tubular body when aluminum silicate is composed of a plurality of tubes, in the case of having pores inside particles formed by aggregation, bonding or aggregation of aluminum silicate It can be confirmed by the following method whether carbon is arrange | positioned to the part which does not appear in the appearance of aluminum silicate, such as in the pore of (1).
That is, after the sample is embedded in a thermosetting resin (epoxy resin), cured, molded, and processed, the inside of the aluminum silicate is mechanically polished to expose the inside of the aluminum silicate, thereby It can confirm by observing the part which corresponds with a scanning electron microscope (SEM). Whether or not carbon is disposed inside the aluminum silicate can be confirmed by energy dispersive X-ray spectroscopy (EDX) from the above-mentioned SEM.

[Characteristics of aluminum silicate complex]
The carbon content in the aluminum silicate composite is preferably 0.1% by mass to 50% by mass. If the carbon content ratio is 0.1% by mass or more, the conductivity of the aluminum silicate complex tends to be further improved, and if 50% by mass or less, the metal ion adsorbing ability of the aluminum silicate complex Tend to be able to make more effective use of The carbon content in the aluminum silicate composite is more preferably 0.5% by mass to 40% by mass, and still more preferably 1% by mass to 30% by mass.
The carbon content ratio in the aluminum silicate complex is a mass reduction rate at 800 ° C. for 20 minutes holding at a temperature rising rate of 20 ° C./min using a differential thermal-thermogravimetric analyzer (TG-DTA) It is measured.

Among the Raman spectrum obtained by laser Raman spectroscopy of the excitation wavelength 532nm Aluminum silicate complex, the intensity of the peak appearing in the vicinity of 1360 cm ^-1 Id, the intensity of the peak appearing in the vicinity of 1580 cm ^-1 and Ig, its When intensity ratio Id / Ig (D / G) of both peaks is R value, the R value is preferably 0.1 to 5.0, and more preferably 0.3 to 3.0. Preferably, it is more preferably 0.5 to 1.5. If the R value is 0.1 or more, the surface coating effect by amorphous carbon tends to be excellent, and if it is 5.0 or less, the amount of surface coating carbon tends to be prevented from becoming excessive.

Here, the peak appearing in the vicinity of 1360 cm ⁻¹ is usually a peak identified as corresponding to the amorphous structure of carbon, and means, for example, a peak observed at 1300 cm ^{−1 to} 1400 cm ⁻¹ . Further a peak appearing near 1580 cm ^-1, generally a peak identified as corresponding to the crystal structure of the carbon, for ^example, refers to peaks observed at 1530cm ^-1 ~1630cm -1.
The R value is a Raman spectrum analysis using a Raman spectrum measuring apparatus (for example, Nippon Bunko Co., Ltd., NSR-1000, excitation wavelength 532 nm) with the entire measurement range (830 cm ^{-1 to} 1940 cm ^-1 ) as a baseline. It can be obtained from

The powder resistivity of the aluminum silicate composite is preferably 0.001 Ω · cm to 100 Ω · cm, more preferably 0.001 Ω · cm to 50 Ω · cm, 0.001 Ω · cm to 30 Ω · cm is more preferable, and 0.001 Ω · cm to 10 Ω · cm is particularly preferable. When the powder resistivity of the aluminum silicate complex is 0.001 Ω · cm or more, the metal ion adsorption ability of the aluminum silicate complex tends to be more able to be maintained, and when it is 100 Ω · cm or less, the aluminum silicate complex There is a tendency that the body does not inhibit the electrical characteristics of the lithium ion secondary battery.
The powder resistivity is a value of volume resistivity measured at a pressure of 3842 N / cm ² (382 Kgf / cm ² ) using a powder resistance measurement system (for example, Mitsubishi Chemical Analytech Co., Ltd., Lorester GP). Do.

  The volume average particle diameter of the aluminum silicate complex is preferably 0.1 μm to 100 μm, more preferably 0.5 μm to 50 μm, and still more preferably 1 μm to 30 μm. When the volume average particle diameter of the aluminum silicate composite is 0.1 μm or more, the powder handling property tends to be further improved, and when it is 100 μm or less, a dispersion containing the aluminum silicate composite is obtained. When used to form a coating film, etc., a more homogeneous film tends to be obtained.

The volume average particle size of the aluminum silicate complex is measured using a laser diffraction method. The laser diffraction method can be performed using a laser diffraction type particle size distribution measuring apparatus (for example, SALD 3000J, manufactured by Shimadzu Corporation).
Specifically, the aluminum silicate complex is dispersed in a dispersion medium such as water to prepare a dispersion. With respect to this dispersion, when a volume cumulative distribution curve is drawn from the small diameter side using a laser diffraction type particle size distribution measuring device, a particle diameter (D50) which is 50% cumulative is determined as a volume average particle diameter.
In addition, about the "volume average particle diameter" in this specification, all use the value measured according to the said method.

  The aluminum silicate in the aluminum silicate complex is selected from the group consisting of imogolite, zeolite, allophane, kaolin, saponite, montmorillonite and attapulgite from the viewpoint of metal ion adsorption ability, metal ion selectivity and electrical properties. It is preferable that there is at least one.

Among the above, as an imogolite, from the viewpoint of metal ion adsorption ability, metal ion selectivity and electrical properties, the element molar ratio Si / Al is 0.3 to 1.0 (preferably 0.3 to less than 1.0). And more preferably any one of the following (1) to (6) or two or more of these properties.
(1) It has a peak in the vicinity of 3 ppm in the ²⁷ Al-NMR spectrum.
(2) It has a peak in the vicinity of -78 ppm and in the vicinity of -85 ppm in the ²⁹ Si-NMR spectrum.
(3) It has peaks at 2θ = 26.9 ° and 40.3 ° and no peaks at 2θ = 20 ° and 35 ° in the powder X-ray diffraction spectrum using a CuKα ray as an X-ray source.
(4) The area ratio (peak B / peak A) of peak B in the vicinity of -85 ppm to peak A in the vicinity of -78 ppm in the ²⁹ Si-NMR spectrum is 2.0 to 9.0.
(5) The BET specific surface area is 250 m ² / g or more.
(6) The water content is 10% by mass or less.

[Method for producing aluminum silicate complex]
The method for producing an aluminum silicate composite includes a step of obtaining an aluminum silicate, and a carbon applying step of applying carbon to the surface of the obtained aluminum silicate, and optionally includes other steps. .

(Step of obtaining aluminum silicate)
The step of obtaining the aluminum silicate may be any step as long as it is possible to obtain the aluminum silicate to which the carbon is to be applied, and may be a step including the preparation of the aluminum silicate. And the step of producing an aluminum silicate from it. For the method of producing aluminum silicate, the methods described above for various aluminum silicates can be applied. As preparation of aluminum silicate, obtaining a commercial item etc. and using it as it is mentioned is mentioned.

(Carbon application process)
In the carbon application step, carbon is applied to the surface of the aluminum silicate. Thereby, carbon is disposed on the surface of the aluminum silicate. There is no restriction | limiting in particular as a method of providing carbon to the surface of aluminum silicate, Methods, such as a wet mixing method, a dry mixing method, a chemical vapor deposition method, are mentioned. The wet mixing method (the “wet method” is referred to as being easy to equalize the thickness of carbon deposited on the surface of aluminum silicate, easy to control the reaction system, and capable of processing under atmospheric pressure. Or dry mixing (sometimes referred to as "gas phase") is preferred.

In the case of the wet mixing method, for example, aluminum silicate and a solution in which a carbon source is dissolved in a solvent are mixed, a solution of the carbon source is attached to the surface of the aluminum silicate, and the solvent is used if necessary. Can be carbonized to apply carbon to the surface of the aluminum silicate by heat treatment under an inert atmosphere. In the case where the carbon source is not dissolved in the solvent, for example, the carbon source may be dispersed in a dispersion medium.
The content of the carbon source in the solution or dispersion liquid of the carbon source is preferably 0.01% by mass to 30% by mass and 0.05% by mass to 20% by mass from the viewpoint of easiness of dispersion. Is more preferably 0.1% by mass to 10% by mass. The mixing ratio of aluminum silicate to carbon source (aluminum silicate: carbon source) is 100: 1 to 100: 500 in mass ratio from the viewpoint of coexistence of metal ion adsorption ability and conductivity. Is preferable, and 100: 5 to 100: 300 is more preferable.

In the case of the dry mixing method, for example, the aluminum silicate and the carbon source are mixed with each other to form a mixture, and the mixture is heat-treated under an inert atmosphere to carbonize the carbon source to obtain an aluminum silicate The surface of the salt can be provided with carbon. In addition, when mixing aluminum silicate and a carbon source, you may perform the process (for example, mechanochemical process) which adds mechanical energy.
As a mixing ratio of aluminum silicate and carbon source when mixing aluminum silicate and carbon source with each other as solid (aluminum silicate: carbon source), a viewpoint of coexistence of metal ion adsorption ability and conductivity Therefore, the mass ratio is preferably 100: 1 to 100: 500, and more preferably 100: 5 to 100: 300.

  When carbon is applied to the surface of aluminum silicate by a wet mixing method or a dry mixing method, the carbon source is not particularly limited as long as it is a compound which can leave carbon by heat treatment, specifically, , High molecular compounds such as phenolic resin, styrene resin, polyvinyl alcohol, polyvinyl chloride, polyvinyl acetate, and polybutyral; ethylene heavy end pitch, coal pitch, petroleum pitch, coal tar pitch, asphalt decomposition pitch, polyvinyl chloride (PVC (PVC) And the like. Pitches such as naphthalene pitch prepared by polymerizing in the presence of super acid, such as PVC pitch which is generated by thermal decomposition of etc .; naphthalene pitch etc .; polysaccharides such as starch, cellulose etc .; You may use these carbon sources individually by 1 type or in combination of 2 or more types.

  In the case of a chemical vapor deposition method, known methods can be applied, for example, applying carbon to the surface of aluminum silicate by heat treating aluminum silicate in an atmosphere containing a gas that has vaporized a carbon source. Can.

  When carbon is applied to the surface of aluminum silicate by chemical vapor deposition, as the carbon source, aliphatic hydrocarbons, aromatic hydrocarbons, alicyclic hydrocarbons, derivatives thereof, etc., among them, gaseous or easy It is preferable to use a gasifiable compound. Specific examples thereof include hydrocarbons such as methane, ethane, propane, toluene, benzene, xylene, styrene, naphthalene and anthracene, and derivatives thereof such as cresol. These carbon sources may be used alone or in combination of two or more.

  The heat treatment temperature for carbonizing the carbon source is not particularly limited as long as the carbon source carbonizes, and is preferably 500 ° C. or more, more preferably 600 ° C. or more, and 700 ° C. or more It is further preferred that Moreover, from the viewpoint of making carbon low in crystallinity, the temperature is preferably 1300 ° C. or less, more preferably 1200 ° C. or less, and still more preferably 1100 ° C. or less.

  The heat treatment time is appropriately selected depending on the type of carbon source to be used or the application amount thereof, and is preferably 0.1 hour to 10 hours, and more preferably 0.5 hour to 5 hours.

  The heat treatment is preferably performed in an inert atmosphere such as nitrogen or argon. The heat treatment apparatus is not particularly limited as long as it is a reaction apparatus having a heating mechanism, and examples thereof include a heating apparatus capable of processing by a continuous method, a batch method, and the like. Specifically, a fluidized bed reactor, a rotary furnace, a vertical moving bed reactor, a tunnel furnace, a batch furnace and the like can be appropriately selected according to the purpose.

  The heat-treated product obtained by the heat treatment may preferably be crushed because individual particles may be agglomerated. Further, when adjustment to a desired average particle size is required, further pulverization may be performed.

  Further, as another method of applying carbon to the surface of aluminum silicate, for example, as carbon to be applied to the surface of aluminum silicate, amorphous carbon such as soft carbon, hard carbon, etc. Carbon such as graphite The method of using a substance is mentioned. According to this method, as shown in FIGS. 10 and 11, it is also possible to produce an aluminum silicate composite in which carbon 40 is present as particles on the surface of aluminum silicate 50. As a method of using a carbonaceous material, the above-mentioned wet mixing method or dry mixing method can be applied.

  When the wet mixing method is applied, particles of the carbonaceous material and a dispersion medium are mixed to form a dispersion, and the dispersion and the aluminum silicate are further mixed to form a surface of the aluminum silicate. It is prepared by depositing the dispersion and drying it followed by heat treatment. When a binder is used, particles of a carbonaceous substance, an organic compound serving as a binder (a compound capable of leaving carbon by heat treatment), and a dispersion medium are mixed to form a mixture, and this mixture and aluminum silica Carbon can also be applied to the surface of aluminum silicate by depositing the mixture on the surface of aluminum silicate by further mixing with an acid salt, and heat treating it after drying. The organic compound is not particularly limited as long as it is a compound which can leave carbon by heat treatment. Moreover, the heat treatment condition in the case of applying a wet mixing method can apply the heat treatment condition for carbonizing the said carbon source.

  In the case of applying the dry mixing method, a process of mixing particles of a carbonaceous material and an aluminum silicate with each other to form a mixture and applying mechanical energy to this mixture as required (for example, mechanochemical treatment) It is produced by performing. Incidentally, even in the case of applying the dry mixing method, it is preferable to carry out a heat treatment in order to form crystallites of silicon in aluminum silicate. As heat treatment conditions in the case of applying the dry mixing method, heat treatment conditions for carbonizing the carbon source can be applied.

  In the case where the aluminum silicate is obtained by production, the method of producing an aluminum silicate complex comprises supplying a carbon source at any stage of the step of obtaining the aluminum silicate to obtain the aluminum silicate. The carbon may be disposed on the surface of the substrate to obtain an aluminum silicate complex. In this production method, a carbon source is supplied to a dispersion of aluminum silicate after synthesis or desalting, and the resulting aluminum silicate dispersion containing the carbon source is heat-treated to carbonize the carbon source. Can be By heat-treating the carbon source-containing dispersion, an aluminum silicate composite having carbon on the surface can be obtained.

  When supplying a carbon source to the dispersion of aluminum silicate, the content of the carbon source in the dispersion is preferably 0.005% by mass to 5% by mass, and 0.01% by mass to 3% by mass Is more preferably 0.05% by mass to 1.5% by mass. By setting the content of the carbon source to 0.005% by mass or more, the conductivity of the aluminum silicate complex tends to be further improved, and by setting the content to 5% by mass or less, the aluminum silicate complex There is a tendency that the metal ion adsorption capacity can be used more effectively.

<Other ingredients>
The conductive material for a lithium ion secondary battery of the present invention can contain any component in addition to the aluminum silicate complex. The other components that can be contained in the conductive material for lithium ion secondary batteries are not particularly limited as long as they can be generally contained in the conductive material for lithium ion secondary batteries. Examples of other components that can be contained in the conductive material for lithium ion secondary batteries include carbon black, graphite, acetylene black, oxides exhibiting conductivity, nitrides exhibiting conductivity, and the like. Among them, the conductive material for a lithium ion secondary battery of the present invention preferably contains acetylene black from the viewpoint of ease of use when made into a slurry.

<Composition for forming lithium ion secondary battery negative electrode>
The composition for lithium ion secondary battery negative electrode formation of this invention contains the above-mentioned electrically conductive material for lithium ion secondary batteries, a negative electrode active material, and a binder. The composition for forming a lithium ion secondary battery negative electrode of the present invention may further contain a solvent, a thickener, a conductive additive and the like.

  The content of the aluminum silicate complex in the composition for forming a lithium ion secondary battery negative electrode is not particularly limited, and, for example, the composition for forming a lithium ion secondary battery anode excluding a solvent used as necessary 0.1% by mass to 30% by mass, preferably 0.3% by mass to 20% by mass, and more preferably 0.5% by mass to 10% by mass with respect to the total amount of preferable.

  As a negative electrode active material, the normal thing used for the negative electrode for lithium ion secondary batteries can be applied. Examples of the negative electrode active material include carbon materials which can be doped or intercalated with lithium ions, metal compounds, metal oxides, metal sulfides, conductive polymer materials, etc. Natural graphite, artificial graphite, silicon, Lithium titanate etc. are mentioned. These negative electrode active materials can be used singly or in combination of two or more.

  The binder is not particularly limited. Examples thereof include styrene-butadiene copolymer; methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, (meth) acrylonitrile, hydroxyethyl (meth) acrylate and the like (Meth) acrylic copolymer obtained by copolymerizing ethylenic unsaturated carboxylic acid ester of the present invention with an ethylenically unsaturated carboxylic acid such as acrylic acid, methacrylic acid, itaconic acid, fumaric acid and maleic acid; Polymer compounds such as vinylidene, polyethylene oxide, polyepichlorohydrin, polyphosphazene, polyacrylonitrile, polyimide, polyamideimide and the like can be mentioned. In addition, "(meth) acrylate" means "acrylate" and the corresponding "methacrylate." The same applies to other similar expressions such as "(meth) acrylic copolymer".

  The solvent is not particularly limited, and N-methylpyrrolidone, dimethylacetamide, dimethylformamide, γ-butyrolactone and the like can be used.

  The thickener is not particularly limited, and carboxymethylcellulose, methylcellulose, hydroxymethylcellulose, ethylcellulose, polyvinyl alcohol, polyacrylic acid (salt), oxidized starch, phosphorylated starch, casein and the like can be used.

  There is no restriction | limiting in particular as a conductive support agent, Carbon black, acetylene black, the oxide which shows electroconductivity, the nitride which shows electroconductivity, etc. can be used. You may use these conductive support agents individually by 1 type or in combination of 2 or more types.

<Composition for forming lithium ion secondary battery positive electrode>
The composition for lithium ion secondary battery positive electrode formation of this invention contains the above-mentioned electrically conductive material for lithium ion secondary batteries, a positive electrode active material, and a binder. The composition for forming a lithium ion secondary battery positive electrode of the present invention may further contain a solvent, a thickener, a conductive additive and the like.

  The content of the aluminum silicate complex in the composition for forming a lithium ion secondary battery positive electrode is not particularly limited, and, for example, the composition for forming a lithium ion secondary battery positive electrode excluding a solvent used as necessary 0.1% by mass to 30% by mass, preferably 0.3% by mass to 20% by mass, and more preferably 0.5% by mass to 10% by mass with respect to the total amount of preferable.

As a positive electrode active material, the normal thing used for the positive electrode for lithium ion secondary batteries can be applied. The positive electrode active material may be a compound capable of doping or intercalating lithium ions, for example, lithium cobaltate (LiCoO ₂ ), lithium nickelate (LiNiO ₂ ), lithium manganate (LiMnO ₂ ), and nickel manganese cobalt And lithium oxide (Li (NiMnCo) O ₂ ).

  As a binder in the composition for lithium ion secondary battery positive electrode formation, the binder demonstrated by the composition for lithium ion secondary battery negative electrodes can be mentioned. As the solvent, the thickener and the conductive additive optionally contained in the composition for forming a lithium ion secondary battery positive electrode, those described in the composition for forming a lithium ion secondary battery negative electrode can be mentioned.

<Anode for lithium ion secondary battery>
The negative electrode for a lithium ion secondary battery of the present invention (hereinafter sometimes referred to as “negative electrode”) comprises a current collector, the conductive material for a lithium ion secondary battery described above provided on the current collector, and the negative electrode active. And a negative electrode layer containing a substance.
For example, the negative electrode for a lithium ion secondary battery of the present invention is prepared after preparing the composition for forming a lithium ion secondary battery negative electrode described above and applying the composition for forming a lithium ion secondary battery negative electrode to a current collector, It is obtained by removing the solvent contained optionally and press-forming to form a negative electrode layer. In general, the composition for forming a lithium ion secondary battery negative electrode is formed into a sheet shape, a pellet shape or the like after kneading.
In addition, when the negative electrode for lithium ion secondary batteries of this invention is manufactured using the composition for lithium ion secondary battery negative electrodes, a binder is contained in a negative electrode layer.

  The material of the current collector is not particularly limited, and examples thereof include aluminum, copper, nickel, titanium, stainless steel, porous metal (foam metal) and carbon paper. The shape of the current collector is not particularly limited, and examples thereof include foil, pierced foil and mesh.

  It does not specifically limit as a method to apply the composition for lithium ion secondary battery negative electrode formation to a collector, For example, a metal mask printing method, an electrostatic coating method, a dip coating method, a spray coating method, a roll coating method, The doctor blade method, the gravure coat method and the screen printing method can be mentioned. After application, it is preferable to carry out pressure treatment with a flat press, a calender roll, etc., as necessary. Moreover, integration of the composition for lithium ion secondary battery negative electrode formation shape | molded in the shape of a sheet form, pellet form, etc., and a collector is integration by roll, integration by a press, and these combination, for example It can be done by integration.

  The negative electrode layer formed on the current collector or the negative electrode layer integrated with the current collector is preferably heat-treated in accordance with the used binder. For example, when using a binder containing polyacrylonitrile as a main skeleton, heat treatment is preferably performed at 100 ° C. to 180 ° C. When using a binder containing polyimide or polyamideimide as a main skeleton, 150 ° C. to Heat treatment at 450 ° C. is preferred. This heat treatment promotes the removal of the solvent used and the hardening of the binder to increase the strength as needed, and the adhesion between the negative electrode material and the adhesion between the negative electrode material and the current collector tend to be enhanced. Note that these heat treatments are preferably performed in an inert atmosphere such as helium, argon, or nitrogen, or in a vacuum atmosphere, in order to prevent oxidation of the current collector during processing.

Moreover, it is preferable to press (pressurize) the negative electrode before heat treatment. The electrode density can be adjusted by pressure treatment. It The negative electrode for a lithium ion secondary battery of the present invention, it is preferable that the electrode density of ^{1.4g / cm 3 ~1.9g / cm 3} , a 1.5g / cm ³ ~1.85g / cm 3 it is more ^preferable, and further preferably from ^{1.6g / cm 3 ~1.8g / cm 3} . As for the electrode density, the higher the value, the more the volume capacity of the negative electrode tends to be improved, and the more the adhesion between the negative electrode materials and the adhesion between the negative electrode material and the current collector tend to be improved.

<Positive electrode for lithium ion secondary battery>
The positive electrode for a lithium ion secondary battery of the present invention (hereinafter sometimes referred to as “positive electrode”) comprises a current collector, the conductive material for a lithium ion secondary battery described above provided on the current collector, and a positive electrode active. And a positive electrode layer containing a substance.
As a collector in the positive electrode for lithium ion secondary batteries, the collector demonstrated by the negative electrode for lithium ion secondary batteries can be mentioned. The positive electrode for a lithium ion secondary battery is the same as in the method for producing a negative electrode for a lithium ion secondary battery described above, except that the composition for forming a lithium ion secondary battery negative electrode is replaced with the composition for forming a lithium ion secondary battery positive electrode. It can be manufactured by the method of

<Lithium ion secondary battery>
The lithium ion secondary battery of the present invention includes at least one of the above-described negative electrode for a lithium ion secondary battery and the above-described positive electrode for a lithium ion secondary battery. When using negative electrodes other than the above-mentioned negative electrode for lithium ion secondary batteries, the normal negative electrode used for a lithium ion secondary battery is applicable. Moreover, when using positive electrodes other than the above-mentioned positive electrode for lithium ion secondary batteries, the normal positive electrode used for a lithium ion secondary battery is applicable.
The negative electrode and the positive electrode are disposed to face each other, for example, via a separator, and a lithium ion secondary battery can be formed by injecting an electrolytic solution containing an electrolyte.

  The electrolyte is not particularly limited, and a known one can be used. For example, a non-aqueous lithium ion secondary battery can be manufactured by using, as the electrolytic solution, a solution in which an electrolyte is dissolved in an organic solvent.

As the electrolyte, for _{example, LiPF 6, LiClO 4, LiBF} 4, LiClF 4, LiAsF 6, LiSbF 6, LiAlO 4, LiAlCl 4, LiN (CF 3 SO 2) 2, LiN (C 2 F 5 SO 2) 2 , LiC (CF ₃ SO ₂ ) ₃ , LiCl and LiI.

  Various known separators can be used as the separator. Specifically, paper separators, polypropylene separators, polyethylene separators, glass fiber separators and the like can be mentioned.

  As a method of manufacturing a lithium ion secondary battery, for example, first, two electrodes of a positive electrode and a negative electrode are wound via a separator. The obtained spiral wound group is inserted into the battery can, and the tab terminal previously welded to the current collector of the negative electrode is welded to the bottom of the battery can. An electrolytic solution is injected into the obtained battery can, and a tab terminal previously welded to the current collector of the positive electrode is welded to the lid of the battery, and the lid is disposed on the upper portion of the battery can via the insulating gasket. The battery is obtained by caulking and sealing a portion where the lid and the battery can are in contact with each other.

  Although the form of the lithium ion secondary battery of the present invention is not particularly limited, lithium ion secondary batteries such as paper type battery, button type battery, coin type battery, laminated type battery, cylindrical type battery, square type battery and the like can be mentioned. .

  EXAMPLES The present invention will next be described by way of examples, but the scope of the present invention is not limited to these examples.

-Manufacture of aluminum silicate 1-
Production Example 1
Concentration: An aqueous solution of aluminum chloride (500 mL) at a concentration of 700 mmol / L was added with an aqueous solution of sodium orthosilicate (500 mL) at a concentration of 350 mmol / L and stirred for 30 minutes. To this solution was added 330 mL of a 1 mol / L aqueous solution of sodium hydroxide to adjust the pH to 6.1.

After stirring the pH-adjusted solution for 30 minutes, centrifugation was performed for 5 minutes at a rotational speed of 3,000 revolutions / minute using Tommy Seiko Co., Ltd .: Suprema 23 and Standard Rotor NA-16 as centrifuges. After centrifugation, the supernatant solution was drained, and the gel-like precipitate was redispersed in pure water and returned to the volume before centrifugation. Such desalting treatment by centrifugation was performed three times.
The gelled precipitate obtained after the third desalting treatment supernatant discharge is dispersed in pure water so that the concentration becomes 60 g / L, and the Horiba, Ltd .: F-55 and conductivity cell: 9382-10D. It was 1.3 S / m, when the electrical conductivity was measured at normal temperature (25 degreeC) using it.

The gelled precipitate obtained after the third desalting treatment supernatant discharge was adjusted to pH 3.5 by adding 135 mL of hydrochloric acid at a concentration of 1 mol / L, and stirred for 30 minutes. The silicon atom concentration and the aluminum atom concentration in the solution at this time are measured by an ordinary method using an ICP emission spectrometer (P-4010, Hitachi, Ltd.), and the concentration of the silicon atom is 213 mmol / L, aluminum The concentration of atoms was 426 mmol / L.
The solution was then placed in an oven and heated to 98 ° C. for 48 hours (2 days).

To the solution after heating (aluminum silicate concentration: 47 g / L), 188 mL of a 1 mol / L aqueous solution of sodium hydroxide was added to adjust the pH to 9.1. The aluminum silicate in the solution was flocculated by adjusting the pH, this flocculate was precipitated by centrifugation as above, and then the supernatant was drained. The precipitate after draining the supernatant was subjected to desalting treatment three times by adding pure water and restoring the same volume as before centrifugation.
The gelled precipitate obtained after the third desalting treatment supernatant discharge is dispersed in pure water so that the concentration becomes 60 g / L, and the Horiba, Ltd .: F-55 and conductivity cell: 9382-10D. It was 0.6 S / m, when the electrical conductivity was measured at normal temperature (25 degreeC) using it.

The gelled precipitate obtained after the third desalting treatment supernatant discharge was dried at 60 ° C. for 16 hours to obtain 30 g of powder. This powder was named sample A. The sample A was confirmed to be imogolite as a result of confirmation by ²⁷ Al-NMR, ²⁹ Si-NMR, ICP emission spectral analysis, and powder X-ray diffraction described later.

<BET specific surface area, total pore volume, average pore diameter>
The BET specific surface area, the total pore volume, and the average pore diameter of sample A were measured based on the nitrogen adsorption capacity. A nitrogen adsorption measuring device (AUTOSORB-1, QUANTACHROME) was used as an evaluation device. When performing these measurements, the evaluation temperature is set to 77 K after the pretreatment of the sample described later, and the evaluation pressure range is set to less than 1 in relative pressure (equilibrium pressure relative to saturated vapor pressure).

  As a pretreatment, deaeration and heating were automatically performed by a vacuum pump on the measurement cell into which 0.05 g of the sample A was charged. The detailed conditions of this treatment were set such that after reducing the pressure to 10 Pa or less, heating at 110 ° C. and holding for 3 hours or more, natural cooling to normal temperature (25 ° C.) was performed while maintaining the reduced pressure.

As a result of the evaluation, the BET specific surface area of sample A was 363 m ² / g, the volume average particle diameter was 5 μm, the total pore volume was 0.22 cm ³ / g, and the average pore diameter was 2.4 nm.

<Volume average particle diameter>
When the volume average particle diameter of the sample A was measured by the following method, the volume average particle diameter was 5.0 μm.
A measurement sample (5 mg) was placed in a 0.01% by mass aqueous solution of surfactant (Esomin T / 15, Lion Corporation) and dispersed with a vibrating stirrer. The obtained dispersion was placed in a sample water tank of a laser diffraction type particle size distribution measuring apparatus (SALD 3000J, Shimadzu Corporation), circulated by a pump while applying ultrasonic waves, and measured by a laser diffraction type. The measurement conditions were as follows. The volume-accumulated 50% particle size (D 50%) of the obtained particle size distribution was taken as the volume average particle size. Hereinafter, in Examples, the measurement of the volume average particle size was performed in the same manner.
Light source: red semiconductor laser (690 nm)
Absorbance: 0.10 to 0.15
-Refractive index: 2.00-0.20i

< ²⁷ Al-NMR>
^As a measurement apparatus of <27> Al-NMR spectrum, it measured on condition of the following using nuclear magnetic resonance spectroscopy apparatus (AV400WB type | mold, Bruker biospin corporation | Co., Ltd. | KK).

Resonance frequency: 104 MHz
Measurement method: MAS (single pulse)
MAS rotation speed: 10 kHz
Measurement area: 52 kHz
Number of data points: 4096
resolution (measurement area / number of data points): 12.7 Hz
Pulse width: 3.0 μsec
Delay time: 2 seconds
Chemical shift value standard: 3.94 ppm of α-alumina
window function: Exponential function Line Broadening coefficient: 10 Hz

The spectrum of ²⁷ Al-NMR of sample A is shown in FIG. As shown in FIG. 1, it had a peak around 3 ppm. Also, a slight peak was observed around 55 ppm. The area ratio of the peak around 55 ppm (the peak around 55 ppm / the peak around 3 ppm) to the peak around 3 ppm was 15%.

< ²⁹ Si-NMR>
^{As a} <29> Si-NMR spectrum measuring apparatus, it measured on condition of the following using nuclear-magnetic-resonance-spectroscopy apparatus (AV400WB type | mold, Bruker biospin corporation | Co., Ltd. | KK).

Resonant frequency: 79.5 MHz
Measurement method: MAS (single pulse)
MAS speed: 6 kHz
Measurement area: 24 kHz
Number of data points: 2048
resolution (measurement area / number of data points): 5.8 Hz
Pulse width: 4.7 μsec
Delay time: 600 sec
Chemical shift value criteria: _TMSP-d 4 (3- (trimethylsilyl) (2,2,3,3- ² H ₄₎ propionate) 1.52Ppm the
window function: Exponential function Line Broadening coefficient: 50 Hz

The spectrum of ²⁹ Si-NMR of sample A is shown in FIG. As shown in FIG. 2, it had peaks at around -78 ppm and around -85 ppm. The areas of peaks around -78 ppm and -85 ppm were measured by the above method. As a result, when the area of peak A at −78 ppm was 1.00, the area of peak B at −85 ppm was 2.61.

<Element molar ratio Si / Al>
The elemental molar ratio Si / Al of Si and Al determined from conventional ICP emission spectrometry (ICP emission spectrometer: P-4010, Hitachi, Ltd.) was 0.5.

<Powder X-ray diffraction>
Powder X-ray diffraction was performed using Rigaku Corporation Geigerflex RAD-2X (product name) using CuKα radiation of wavelength 0.15418 nm as an X-ray source. The spectrum of powder X-ray diffraction of sample A is shown in FIG. Broad peaks were observed around 2θ = 26.9 ° and around 40.3 °. In addition, sharp peaks were observed around 2θ = 18.8 °, 20.3 °, 27.8 °, 40.6 ° and 53.3 °. In addition, broad peaks were not observed around 2θ = 20 ° and 35 °.

<Transmission electron microscope (TEM) photo observation>
FIG. 4 shows a transmission electron microscope (TEM) photograph of the sample A observed at 100,000 ×. In addition, TEM observation was performed at an acceleration voltage of 100 kV using a transmission electron microscope (Hitachi High-Technologies Corporation H-7100 FA type). The sample A to be subjected to TEM observation was prepared as follows. That is, the solution after heating (aluminum silicate concentration 47 g / L) before the final desalting treatment step was diluted 10 times with pure water and subjected to ultrasonic irradiation treatment for 5 minutes for TEM observation sample preparation The solution was dropped onto a support for use and then air-dried to form a thin film.
As shown in FIG. 4, in the sample A, there was no tubular having a length of 50 nm or more.

<Water content rate>
The moisture content of the sample A was heated at 120 ° C. under atmospheric pressure, held for 6 hours, and measured by the Karl-Fisher method. As a result, it was 3% by mass.

<Metal ion adsorption capacity in water 1>
The metal ion adsorption ability of the sample A was evaluated by ICP emission spectrometry (ICP emission spectrometer: P-4010, Hitachi, Ltd.).
In the evaluation of the metal ion adsorption ability, first, 100 ppm metal ion solution was prepared using each metal sulfate and pure water for Ni ²⁺ , Mn ²⁺ or Li ⁺ . Sample A was added to the metal ion solution to a final concentration of 1.0% by mass, mixed thoroughly, and allowed to stand. And each metal ion concentration before and behind addition of the sample A was measured by ICP emission spectral analysis. The results are shown in Table 1.

Regarding the metal ion adsorption capacity, the concentration after the addition of sample A was less than 5 ppm for Ni ²⁺ and 10 ppm for Mn ²⁺ . On the other hand, Li ⁺ was hardly adsorbed at 90 ppm. Therefore, the sample A adsorbs Ni ²⁺ and Mn ²⁺ but hardly adsorbs Li ^+, so that a short circuit can be further suppressed in a lithium ion secondary battery in which nickel ions and manganese ions can be unnecessary metal ions. .

Moreover, the following sample B and sample C were prepared as a reference, and metal ion adsorption capacity was evaluated, respectively.
A commercially available activated carbon (Wako Pure Chemical Industries, Ltd., activated carbon, crushed, particle size 2 mm to 5 mm) was used as Sample B. Regarding the metal ion adsorption ability in water, the concentration after addition of sample B was 50 ppm of Ni ²⁺ , 60 ppm of Mn ²⁺ , and 100 ppm of Li ⁺ . The results are shown in Table 1.

A commercially available silica gel (Wako Pure Chemical Industries, Ltd., small granular (white)) was used as Sample C. Regarding the metal ion adsorption ability in water, the concentration after adding sample C was 100 ppm of Ni ²⁺ , 100 ppm of Mn ²⁺ , and 80 ppm of Li ⁺ . The results are shown in Table 1.

<Metal ion adsorption capacity 2 in water>
Using the sample A prepared in Production Example 1, and changing the addition amount of the sample A as shown in Table 2, the metal ion adsorbing ability in water is the method described in "Metal ion adsorbing ability 1 in water" Was evaluated. The results are shown in Table 2.

  As shown in Table 2, when 0.5% by mass of sample A was added, the manganese ion concentration was halved. Then, when 2.0% by mass of sample A was added, 95% of manganese ions were captured.

<Metal ion adsorption capacity 3 in water>
Using the sample A prepared in Production Example 1, except that the metal ion species is changed to Cu ²⁺ and the metal ion adjustment concentration is changed to 400 ppm, the method described in “metal ion adsorption ability 1 in water” is described in water The metal ion adsorption capacity was evaluated. The pH at this time was 5.1. The concentration after addition of sample A was 160 ppm of Cu ²⁺ .

Production Example 2
Concentration: An aqueous solution of aluminum chloride (500 mL) having a concentration of 180 mmol / L was added with an aqueous solution of sodium orthosilicate having a concentration of 74 mmol / L (500 mL) and stirred for 30 minutes. To this solution was added 93 mL of a 1 mol / L aqueous solution of sodium hydroxide to adjust the pH to 7.0.

  After stirring the pH-adjusted solution for 30 minutes, centrifugation was performed for 5 minutes at a rotational speed of 3,000 revolutions / minute using Tommy Seiko Co., Ltd .: Suprema 23 and Standard Rotor NA-16 as centrifuges. After centrifugation, the supernatant solution was drained, and the gel-like precipitate was redispersed in pure water and returned to the same volume as that before centrifugation. Such desalting treatment by centrifugation was performed three times.

  The gel-like precipitate obtained after the third desalting treatment supernatant discharge was adjusted to a concentration of 60 g / L, and using Horiba, Ltd .: F-55 and conductivity cell: 9382-10D, It was 1.3 S / m when the electrical conductivity was measured at normal temperature (25 degreeC).

Pure water was added to the gel-like precipitate obtained after the third desalting treatment, and the volume was adjusted to 12 liters. The pH was adjusted to 4.0 by adding 60 mL of hydrochloric acid at a concentration of 1 mol / L to the solution and stirred for 30 minutes. When the silicon atom concentration and the aluminum atom concentration in the solution at this time were measured using an ICP emission spectrometer: P-4010 (Hitachi, Ltd.), the silicon atom concentration was 2 mmol / L and the aluminum atom concentration was 4 mmol. It was / L.
The solution was then placed in an oven and heated to 98 ° C. for 96 hours (4 days).

  To the solution after heating (aluminum silicate concentration: 0.4 g / L), 60 mL of a 1 mol / L aqueous solution of sodium hydroxide was added to adjust the pH to 9.0. The solution was coagulated by adjusting the pH, and the aggregate was precipitated by centrifugation similar to the first washing step, and the supernatant was discharged. Pure water was added to this, and the desalting process of returning to the same volume as before centrifugation was performed three times.

  The gel-like precipitate obtained after the third desalting treatment supernatant discharge was adjusted to a concentration of 60 g / L, and using Horiba, Ltd .: F-55 and conductivity cell: 9382-10D, It was 0.6 S / m when the electrical conductivity was measured at normal temperature (25 degreeC).

  The gelled precipitate obtained after the desalting treatment was dried at 60 ° C. for 72 hours (3 days) to obtain 4.8 g of powder. This powder was used as sample D.

< ²⁷ Al-NMR>
The spectrum of ²⁷ Al-NMR of sample D is shown in FIG. As shown in FIG. 1, it had a peak around 3 ppm. Also, a slight peak was observed around 55 ppm. The area ratio of the peak around 55 ppm to the peak around 3 ppm was 4%.

< ²⁹ Si-NMR>
The spectrum of ²⁹ Si-NMR of sample D is shown in FIG. As shown in FIG. 2, it had peaks at around -78 ppm and -85 ppm. The areas of peaks around -78 ppm and -85 ppm were measured by the above method. As a result, when the area of peak A near -78 ppm was 1.00, the area of peak B near -85 ppm was 0.44.

<Element molar ratio Si / Al>
The element molar ratio Si / Al of Si and Al of the sample D determined from conventional ICP emission spectrometry (ICP emission spectrometer: P-4010 (Hitachi, Ltd.)) was 0.5.

<Powder X-ray diffraction>
The powder X-ray diffraction of Sample D was performed in the same manner as in Production Example 1. The spectrum of powder X-ray diffraction of sample D is shown in FIG. It had broad peaks around 2θ = 4.8 °, 9.7 °, 14.0 °, 18.3 °, 27.3 ° and 40.8 °. In addition, broad peaks were not observed around 2θ = 20 ° and 35 °.

<BET Specific Surface Area, Total Pore Volume, and Average Pore Diameter>
The BET specific surface area, the total pore volume, and the average pore diameter of Sample D were measured based on the nitrogen adsorption capacity in the same manner as in Production Example 1.
As a result of the evaluation, the BET specific surface area of sample D was 323 m ² / g, the total pore volume was 0.22 cm ³ / g, and the average pore diameter was 2.7 nm.

<Volume average particle diameter>
The volume average particle size of Sample D was measured in the same manner as in Production Example 1. As a result, the volume average particle size was 5.0 μm.

<Transmission electron microscope (TEM) photo observation>
FIG. 5 shows a transmission electron microscope (TEM) photograph of the sample D observed at 100,000 × in the same manner as in Production Example 1. As shown in FIG. As shown in FIG. 5, a tubular is formed, the length in the longitudinal direction of the tubular portion 10a is about 10 nm to 10 μm, the outer diameter is about 1.5 nm to 3.0 nm, and the inner diameter is Was about 0.7 nm to 1.4 nm.

<Water content rate>
The moisture content of the sample D was heated at 120 ° C. under atmospheric pressure and held for 6 hours, and then measured by the Karl Fischer method. As a result, it was 3% by mass.

<Metal ion adsorption ability in water>
When the Mn ²⁺ ion adsorption ability in water of Sample D was evaluated in the same manner as in Production Example 1, Sample D showed the same metal ion adsorption ability as Sample A.

Example 1
Imogolite complex A as an aluminum silicate complex was manufactured as follows using sample A described above.
Sample A and polyvinyl alcohol powder (Wako Pure Chemical Industries, Ltd.) were mixed at a mass ratio of 100: 70, and fired at 850 ° C. for 1 hour in a nitrogen atmosphere. This was designated as imogolite complex A.
The carbon content ratio of the obtained imogolite complex A was measured using a differential thermal-thermogravimetric analyzer (TG-DTA) at a temperature rising rate of 20 ° C./min, to a mass reduction rate at 800 ° C. for 20 minutes. It was 10 mass% when it measured.
Moreover, it was 1.0 when R value of the obtained imogolite complex A was measured on condition of the following. When the mapping state by the Raman spectroscopy was conducted and the covering state of the surface of the imogolite complex A was confirmed, the carbon which is not covered with carbon is very few and most of the surface is covered with carbon. The coating was confirmed.

A Raman spectrum measuring apparatus (Nippon Bunko Co., Ltd., NSR-1000 type) was used for the measurement of R value, and the spectrum obtained made the following range a baseline. The measurement conditions were as follows.
・ Laser wavelength: 532 nm
Irradiation intensity: 1.5mW (measured value with laser power monitor)
Irradiation time: 60 seconds Irradiation area: 4 μm ²
・ Measurement range: 830 cm ^{-1 to} 1940 cm ^-1
・ Baseline: 1050 cm ^{−1 to} 1750 cm ⁻¹

The wave number of the spectrum obtained is the wave number of each peak obtained by measuring the reference substance Indene (Wako Pure Chemical Industries, Ltd., Wako Class 1) under the same conditions as described above, and the wave number theoretical value of each peak of Indene It corrected using the calibration curve calculated | required from the difference of.
Among the Raman spectrum obtained after the correction, the intensity of the peak appearing the intensity of the peak appearing in the vicinity of 1360 cm ^-1 Id, in the vicinity of 1580 cm ^-1 and Ig, its both peak intensity ratio Id / Ig (D / G) Was determined as the R value.

  Mapping was performed under the same conditions using the same Raman spectrum measuring apparatus as that used in the measurement of the R value.

The BET specific surface area of the imogolite complex A was measured based on the nitrogen adsorption capacity in the same manner as in Production Example 1. As a result, the BET specific surface area of the imogolite complex A was 10 m ² / g. Further, the volume average particle diameter of the imogolite complex A was measured in the same manner as in Production Example 1. As a result, the volume average particle size was 5.0 μm.

Example 2
Imogolite complex B as an aluminum silicate complex was manufactured as follows using sample A described above.
The sample A was dispersed in a 1% by mass polyvinyl alcohol aqueous solution and dried at 120 ° C. such that the mixing mass ratio of the aluminum silicate and the carbon source was 100: 70. The dried solid was pulverized and calcined at 850 ° C. for 1 hour under a nitrogen atmosphere. This was designated as imogolite complex B. The carbon content ratio of the obtained imogolite complex B was measured by using a differential thermal-thermogravimetric analyzer (TG-DTA) at a temperature rising rate of 20 ° C./min, at a temperature decrease rate of 800 ° C. for 20 minutes. It was 10 mass% when measured by.
Moreover, it was 1.0 when R value of the obtained imogolite complex B was measured on the conditions same as the above. Mapping by Raman spectroscopy was performed and the coating state of the surface of the imogolite complex B was confirmed. As a result, there were very few parts not covered with carbon and most parts of the surface were covered with carbon. The coating was confirmed.

The BET specific surface area of the imogolite complex B was measured based on the nitrogen adsorption capacity in the same manner as in Production Example 1. As a result, the BET specific surface area of the imogolite complex B was 10 m ² / g. Further, the volume average particle diameter of the imogolite complex B was measured in the same manner as in Production Example 1. As a result, the volume average particle size was 30.0 μm.

  The obtained imogolite composite B is embedded in an epoxy resin, cured and molded, and then mechanically polished to expose the inside of the imogolite composite B, and the portion corresponding to the inside is observed with a scanning electron microscope (SEM) The presence or absence of carbon was examined by energy dispersive X-ray spectroscopy (EDX). As a result, it was confirmed that carbon was present inside the particles of imogolite complex B. In addition, high resolution analysis scanning electron microscope (product name: SU-70, Hitachi High-Technologies Corporation) was used as a scanning electron microscope (SEM) which can also analyze energy dispersive X-ray spectroscopy (EDX).

[Evaluation 1]
The following evaluation was performed on imogolite complexes A and B. As comparative controls, sample A before carbon coating and fired product A obtained by subjecting sample A to a heat treatment at 850 ° C. for 1 hour in a nitrogen atmosphere were used. The BET specific surface area of the calcined product A was measured based on the nitrogen adsorption capacity in the same manner as in Production Example 1. As a result, the BET specific surface area of the baked product A was 5 m ² / g. Moreover, the volume average particle diameter of the baked product A was measured in the same manner as in Production Example 1. As a result, the volume average particle size was 5.0 μm.
In addition, with respect to powder resistivity, conductivity, metal adsorption ability, and charge / discharge characteristics, acetylene black (HS-100, Denki Kagaku Kogyo Co., Ltd.) was further used as a control for comparison. The volume average particle size and the BET specific surface area of this acetylene black were measured by the above-mentioned method and found to be 2.0 μm and 38 m ² / g, respectively.

(1) Powder X-ray Diffraction Powder X-ray diffraction was carried out for the imogolite composites A and B, the sample A before carbon coating, and the fired product A under the same conditions as described for Production Example 1 . The results are shown in FIG. In FIG. 12, black circles indicate peaks indicating amorphous aluminum silicate, black triangles indicate peaks indicating bayerite structure, and black squares indicate peaks indicating mullite structure.
As shown in FIG. 12, it was found that neither of the imogolite complexes A and B showed a peak showing a mullite structure, and the structure derived from the amorphous aluminum silicate was maintained.
On the other hand, in the fired product A, no peak showing the structure of the bayerite structure and the structure of the amorphous aluminum silicate can not be confirmed, and it has the mullite structure and the structure derived from the amorphous aluminum silicate is It turned out that it did not have.

(2) Powder resistivity and conductivity For powder resistivity and conductivity, 3 g of each sample shown in Table 3 is weighed, and a powder resistance measurement system (Lorestar GP, Mitsubishi Chemical Analytech Co., Ltd.) is used. The pressure was measured at 3842 N / cm ² (382 kgf / cm ² ). Zeolite, allophane, kaolin, saponite, montmorillonite and attapulgite used as samples indicate the raw materials used in Examples 3 to 8 described later, and the zeolite complex, allophane complex, kaolin complex, saponite complex, montmorillonite The complex and the attapulgite complex show those prepared in Examples 3 to 8 described later.
The respective results are shown in Table 3.

As shown in Table 3, when compared with the sample A having no carbon on the surface, it can be seen that both imogolite composites A and B have relatively high conductivity.
Also, in zeolite, allophane, kaolin and saponite, respectively, the zeolite complex having carbon on the surface, allophane complex, kaolin complex, saponite complex, montmorillonite complex and attapulgite complex all have powder resistance. It can be seen that the rate is low and the conductivity is high.

(3) Metal (Mn) ion adsorption capacity in electrolyte solution Imogolite complexes A and B, sample A before carbon coating, calcined product A, and acetylene black, as described below, metals in electrolyte solution ( Mn) Ion adsorption capacity was evaluated.
An electrolyte containing 1 M of LiPF ₆ and ethylene carbonate (EC): dimethyl carbonate (DMC): diethyl carbonate (DEC) in a volume ratio of 1: 1: 1 was prepared, and this was prepared with Mn (BF ₄ ) ₂ Dissolve to prepare a 500 ppm Mn solution. After adding 0.05 g of each sample to this Mn solution and stirring for 30 minutes, it was allowed to stand overnight at room temperature (25 ° C.). Thereafter, the supernatant was filtered using a 0.45 μm filter, and the adsorption amount of Mn ions was measured using an ICP emission spectrometer (ICP-AES). The results are shown in FIG.
As shown in FIG. 13, it was found that both imogolite composites A and B have good metal ion adsorption ability compared to acetylene black and calcined product A.

(4) Charge / discharge characteristics 10 parts by mass of polyvinylidene fluoride (PVDF) is added to 90 parts by mass of each of sample A, calcined product A, imogolite complex A, imogolite complex B or acetylene black -It knead | mixed using methyl 2- pyrrolidone (NMP), and obtained the slurry. The obtained slurry was applied onto a copper foil, dried at 105 ° C. for 30 minutes, and pressed to obtain an electrode. The obtained electrode was used as a negative electrode, metal lithium which is a counter electrode was made to face via a 20-μm polypropylene separator, and an electrolytic solution was injected to produce a coin cell (half cell). The electrolytic solution was prepared by dissolving LiPF ₆ in a concentration of 1 mol / L and vinylene carbonate in a mixed solvent of ethyl carbonate and methyl ethyl carbonate (volume ratio: 3 to 7) to a concentration of 0.5 mass%.

  Each cell was placed in a thermostat at 25 ° C., and a charge / discharge test was performed. Charging was performed by charging Li to a working electrode at a voltage of 0.005 V until the current value became 0.01 mA after charging to 0.005 V with a current of 0.1 mA. The discharge was performed by releasing Li to the working electrode at a current value of 0.1 mA to a voltage value of 1.5V. The discharge capacity and the charge and discharge efficiency were taken as the result of the first charge and discharge test.

The results are shown in FIG. 14 and FIG. In FIG. 14, the solid line indicates sample A, the dotted line indicates calcined product A, the solid line indicates imogolite complex A, the broken line indicates imogolite complex B, and the dotted line indicates acetylene black.
As shown in FIG. 14 and FIG. 15, while the initial discharge capacities of the sample A and the fired product A were 0.3 mAh / g to 0.4 mAh / g, carbon was coated by the vapor phase method or the wet method. It was found that the imogolite complex A and the imogolite complex B have an initial discharge capacity of 220 mAh / g to 280 mAh / g, and have performance equal to or more than 205 mAh / g of acetylene black.

(5) Storage test (addition to the negative electrode)
1 part by mass of acetylene black, 3 parts by mass of polyvinylidene fluoride (PVDF) and 91 parts by mass of graphite are added to 5 parts by mass of imogolite complex A, and N-methyl-2-pyrrolidone (NMP) The mixture was kneaded to obtain a slurry. It apply | coated on copper foil using the obtained slurry, after pressing for 30 minutes at 105 degreeC, the press was performed and the negative electrode A was obtained. As a comparison, 1 part by mass of acetylene black, 3 parts by mass of polyvinylidene fluoride (PVDF), and 96 parts by mass of graphite were added and kneaded using N-methyl-2-pyrrolidone (NMP) to obtain The negative electrode X was obtained in the same manner using the slurry.

  8 parts by mass of acetylene black, 6 parts by mass of polyvinylidene fluoride (PVDF), 86 parts by mass of spinel manganese (lithium manganate), mixed, and kneaded using N-methyl-2-pyrrolidone (NMP) , I got a slurry. It apply | coated on aluminum foil using the obtained slurry, after pressing for 30 minutes at 105 degreeC, the press was performed and the positive electrode X was obtained.

The negative electrode A or the negative electrode X and the positive electrode X were each vacuum dried at 130 ° C. for 6 hours, and then the negative electrode and the positive electrode were made to face each other through a 20 μm polypropylene separator to inject an electrolytic solution to produce a coin cell. The electrolytic solution was prepared by dissolving LiPF ₆ in a concentration of 1 mol / L and vinylene carbonate in a mixed solvent of ethyl carbonate and methyl ethyl carbonate (volume ratio: 3 to 7) to a concentration of 0.5 mass%. The coin cell produced using the negative electrode A and the positive electrode X was made into cell A-1. Further, in the same manner as the above method, however, a standard cell was produced using the negative electrode X and the positive electrode X.

(Addition to positive electrode)
To 3 parts by mass of imogolite composite A, 5 parts by mass of acetylene black, 6 parts by mass of polyvinylidene fluoride (PVDF), and 86 parts by mass of spinel manganese (lithium manganate) are added to obtain N-methyl The slurry was obtained by kneading using -2-pyrrolidone (NMP). It apply | coated on aluminum foil using the obtained slurry, after pressing for 30 minutes at 105 degreeC, the press was performed and the positive electrode A was obtained. As a comparison, the positive electrode X was used. The negative electrode X was used as the negative electrode.
Each of the negative electrode and the positive electrode was vacuum dried at 130 ° C. for 6 hours, and made to face each other through a 20 μm polypropylene separator, and an electrolytic solution was injected to produce a coin cell. The electrolytic solution was prepared by dissolving LiPF ₆ in a concentration of 1 mol / L and vinylene carbonate in a mixed solvent of ethyl carbonate and methyl ethyl carbonate (volume ratio: 3 to 7) to a concentration of 0.5 mass%. A coin cell manufactured using the positive electrode A and the negative electrode X was referred to as a cell C-1.

(Storage condition)
For each of cell A-1, cell C-1 and standard cell, after being placed in a thermostatic chamber at 25 ° C., the voltage is 4.2 V and the current is 0.46 mA. It was charged to 0046 V and then discharged at a current of 0.46 mA to 2.7 V. Next, each cell was charged to 0.0046 V by constant current, constant voltage charging at a voltage of 4.2 V and a current of 0.46 mA to obtain a charging capacity (first charge capacity before leaving). Each charged cell was placed in a 60 ° C. thermostat and allowed to stand for 7 days. Each cell after standing was discharged with a current of 0.46 mA to 2.7 V to obtain a discharge capacity (first discharge capacity after leaving for 7 days). (First discharge capacity after leaving for 7 days) / (initial charge capacity before leaving) was taken as the capacity retention rate. As a result of comparing the capacity retention rate of each cell, the cell A-1 has an improvement in the capacity retention rate of 0.5% as compared with the standard cell. In addition, in the cell C-1, the capacity retention rate was improved by 5% as compared to the standard cell.
From this, it was found that by adding the imogolite complex to the negative electrode or the positive electrode of the lithium ion secondary battery, the capacity retention rate is improved as compared with the case where the imogolite complex is not added.

  Furthermore, cells A-2 and C-2 were manufactured in the same manner as the method for manufacturing cell A-1 and cell C-1, except that imogolite complex A was changed to imogolite complex B. For cell A-2 and cell C-2, charge capacity (initial charge capacity before leaving), discharge capacity (initial discharge capacity after leaving for 7 days), capacity retention rate (after leaving for 7 days) according to the method described above Initial discharge capacity) / (initial charge capacity before leaving) was measured. As a result of comparing the capacity retention rate of each cell, the capacity retention rate of the cell A-2 was improved by 0.5% as compared to the standard cell. In addition, in the cell C-2, the capacity retention rate was improved by 5.0% as compared to the standard cell.

[Example 3]
A zeolite complex as an aluminum silicate complex was prepared as follows.
Product name: SP # 600 (Nitto Powder Co., Ltd.) was used as zeolite. The various physical properties of this zeolite were as follows. The BET specific surface area and the element molar ratio Si / Al were measured under the same conditions as in Production Example 1 above.
BET specific surface area: 250 m ² / g
Element molar ratio Si / Al: 2.8
Volume average particle diameter: 10.0 μm

Sample E was produced as follows using the above zeolite.
The zeolite and polyvinyl alcohol powder (Wako Pure Chemical Industries, Ltd.) were mixed at a mass ratio of 100: 70, and calcined at 850 ° C. for 1 hour in a nitrogen atmosphere. This was used as a zeolite complex.
The carbon content ratio of the obtained zeolite complex is measured using a differential thermal-thermogravimetric analyzer (TG-DTA) at a rate of temperature decrease of 20 ° C./min, at a mass reduction rate at 800 ° C. for 20 minutes. It was 10 mass% when measured.
Moreover, it was 1.0 when R value of the obtained zeolite complex was measured on the same conditions as the above. A mapping by Raman spectroscopy was carried out to confirm the coating state of the surface of the zeolite complex, and it was found that the carbon coating in a state in which the portion not covered by carbon was very few and most of the surface was covered by carbon Was confirmed.

The BET specific surface area of the zeolite complex was measured based on the nitrogen adsorption capacity in the same manner as in Production Example 1. As a result, the BET specific surface area of the zeolite complex was 50 m ² / g. Further, the volume average particle diameter of the zeolite complex was measured in the same manner as in Production Example 1. As a result, the volume average particle diameter was 10.0 μm.

  The obtained zeolite complex is embedded in an epoxy resin, cured and molded, and then mechanically polished to expose the inside of the zeolite complex, and the portion corresponding to the inside is observed with a scanning electron microscope (SEM), The presence or absence of carbon was examined by energy dispersive X-ray spectroscopy (EDX). As a result, it was confirmed that carbon was present inside the particles of the zeolite complex. In addition, high resolution analysis scanning electron microscope (product name: SU-70, Hitachi High-Technologies Corporation) was used as a scanning electron microscope (SEM) which can also analyze energy dispersive X-ray spectroscopy (EDX).

Example 4
The allophane complex as an aluminum silicate complex was produced as follows. Product name: Secard (Shinagawa Chemical Co., Ltd.) was used as allophane. The various physical properties of this allophane were as follows. The BET specific surface area and the element molar ratio Si / Al were measured under the same conditions as in Production Example 1 above.
BET specific surface area: 345 m ² / g
Element molar ratio Si / Al: 0.6
Volume average particle diameter: 13.0 μm

Sample F was prepared as follows using allophane as described above.
Allophane and polyvinyl alcohol powder (Wako Pure Chemical Industries, Ltd.) were mixed at a mass ratio of 100: 70, and baked at 850 ° C. for 1 hour in a nitrogen atmosphere. This was an allophane complex.
The carbon content ratio of the obtained allophane complex was determined using the differential thermal-thermogravimetric analyzer (TG-DTA) at a rate of temperature increase of 20 ° C./min, with the mass loss at 20 ° C. for 20 minutes. It was 10 mass% when it measured.
The R value of the obtained allophane complex was 1.0 under the same conditions as described above. A mapping by Raman spectroscopy was carried out to confirm the coverage of the surface of the allophane complex. As a result, there were very few parts not covered by carbon, and most parts of the surface were covered by carbon. Was confirmed.

The BET specific surface area of the allophane complex was measured based on the nitrogen adsorption capacity in the same manner as in Production Example 1. As a result, the BET specific surface area of the allophane complex was 50 m ² / g. Further, the volume average particle diameter of the allophane complex was measured by the same method as in Production Example 1. As a result, the volume average particle size was 13.0 μm.

[Example 5]
The kaolin complex as an aluminum silicate complex was produced as follows.
Product name: ASP-200 (Hayashi Kasei Co., Ltd.) was used as kaolin. The various physical properties of this kaolin were as follows. The BET specific surface area and the element molar ratio Si / Al were measured under the same conditions as in Production Example 1 above.
BET specific surface area: 20 m ² / g
Element molar ratio Si / Al: 0.6
Volume average particle diameter: 4.0 μm

The sample G was manufactured as follows using the above-mentioned kaolin.
Kaolin and polyvinyl alcohol powder (Wako Pure Chemical Industries, Ltd.) were mixed at a mass ratio of 100: 70, and baked at 850 ° C. for 1 hour in a nitrogen atmosphere. This was made a kaolin complex.
The carbon content ratio of the obtained kaolin complex is measured using a differential thermal-thermogravimetric analyzer (TG-DTA) at a rate of temperature decrease of 20 ° C./min, at a mass reduction rate at 800 ° C. for 20 minutes. It was 10 mass% when measured.
In addition, the R value of the obtained kaolin complex was 1.0 under the same conditions as described above. When the mapping state by the Raman spectroscopy was conducted and the covering state of the surface of the kaolin complex was confirmed, the carbon covering in a state in which the portion not covered with carbon is very few and most part of the surface is covered by carbon Was confirmed.

In the same manner as in Production Example 1, the BET specific surface area of the kaolin complex was measured based on the nitrogen adsorption capacity. As a result, the BET specific surface area of the kaolin complex was 5 m ² / g. Further, the volume average particle diameter of the kaolin complex was measured by the same method as in Production Example 1. As a result, the volume average particle size was 4.0 μm.

[Example 6]
The saponite complex as an aluminum silicate complex was produced as follows.
Product name: Smecton SA (Kunimine Industries, Ltd.) was used as the saponite. The various physical properties of this saponite were as follows. The BET specific surface area and the element molar ratio Si / Al were measured under the same conditions as in Production Example 1 above.
BET specific surface area: 256 m ² / g
Element molar ratio Si / Al: 11
Volume average particle diameter: 38.0 μm

The sample H was manufactured as follows using the above saponite.
Saponite and polyvinyl alcohol powder (Wako Pure Chemical Industries, Ltd.) were mixed at a mass ratio of 100: 70, and fired at 850 ° C. for 1 hour in a nitrogen atmosphere. This was used as a saponite complex.
The carbon content ratio of the obtained saponite complex is measured using a differential thermal-thermogravimetric analyzer (TG-DTA) at a rate of temperature decrease of 800 ° C. for 20 minutes at a temperature rising rate of 20 ° C./min. It was 10 mass% when measured.
Moreover, it was 1.0 when R value of the obtained saponite complex was measured on the same conditions as the above. When the mapping state by the Raman spectroscopy was conducted and the covering state of the surface of the saponite composite was confirmed, the carbon covering state in which the portion not covered with carbon is very few and most part of the surface is covered by carbon Was confirmed.

The BET specific surface area of the saponite complex was measured based on the nitrogen adsorption capacity in the same manner as in Production Example 1. As a result, the BET specific surface area of the saponite complex was 38 m ² / g. Further, the volume average particle diameter of the saponite complex was measured in the same manner as in Production Example 1. As a result, the volume average particle size was 38.0 μm.

  The resulting saponite composite is embedded in an epoxy resin, cured and molded, and then mechanically polished to expose the inside of the saponite composite, and the portion corresponding to the inside is observed with a scanning electron microscope (SEM), The presence or absence of carbon was examined by energy dispersive X-ray spectroscopy (EDX). As a result, it was confirmed that carbon was present inside the particles of the saponite complex. In addition, high resolution analysis scanning electron microscope (product name: SU-70, Hitachi High-Technologies Corporation) was used as a scanning electron microscope (SEM) which can also analyze energy dispersive X-ray spectroscopy (EDX).

[Example 7]
Montmorillonite complex as an aluminum silicate complex was prepared as follows.
As montmorillonite, product name: Kunipia (Kunimine Industrial Co., Ltd.) was used. The various physical properties of this montmorillonite were as follows. The BET specific surface area and the element molar ratio Si / Al were measured under the same conditions as in Production Example 1 above.
BET specific surface area: 20 m ² / g
Element molar ratio Si / Al: 2.4
Volume average particle diameter: 3.0 μm

Sample I was prepared as follows using the montmorillonite described above.
Montmorillonite and polyvinyl alcohol powder (Wako Pure Chemical Industries, Ltd.) were mixed at a mass ratio of 100: 70, and fired at 850 ° C. for 1 hour in a nitrogen atmosphere. This was used as a montmorillonite complex.
The carbon content ratio of the obtained montmorillonite complex is measured using a differential thermal-thermogravimetric analyzer (TG-DTA) at a temperature rising rate of 20 ° C./min, at a mass reduction rate at 800 ° C. for 20 minutes. It was 10 mass% when measured.
The R value of the obtained montmorillonite complex was 1.0 under the same conditions as described above. When the mapping state by the Raman spectroscopy was conducted and the covering state of the surface of the montmorillonite complex was confirmed, the carbon covering state in which the portion not covered with carbon was very few and most part of the surface was covered by carbon Was confirmed.

The BET specific surface area of the montmorillonite complex was measured based on the nitrogen adsorption capacity in the same manner as in Production Example 1. As a result, the BET specific surface area of the montmorillonite complex was 10 m ² / g. Further, the volume average particle diameter of the montmorillonite complex was measured in the same manner as in Production Example 1. As a result, the volume average particle diameter was 3.0 μm.

[Example 8]
The attapulgite complex as an aluminum silicate complex was produced as follows.
Product name: Atagel 50 (Hayashi Kasei Co., Ltd.) was used as attapulgite. The various physical properties of this attapulgite were as follows. The BET specific surface area and the element molar ratio Si / Al were measured under the same conditions as in Production Example 1 above.
BET specific surface area: 150 m ² / g
Element molar ratio Si / Al: 2.7
Volume average particle diameter: 3.0 μm

Sample J was manufactured as follows using the above attapulgite.
Attapulgite and polyvinyl alcohol powder (Wako Pure Chemical Industries, Ltd.) were mixed at a mass ratio of 100: 70, and fired at 850 ° C. for 1 hour in a nitrogen atmosphere. This was used as an attapulgite complex.
The carbon content ratio of the obtained attapulgite complex is measured using a differential thermal-thermogravimetric analyzer (TG-DTA) at a temperature rising rate of 20 ° C./min, at a mass reduction rate at 800 ° C. for 20 minutes. It was 10 mass% when measured.
The R value of the obtained attapulgite complex was 1.0 under the same conditions as described above. A mapping by Raman spectroscopy was carried out to confirm the coverage of the surface of the attapulgite complex. It was found that the carbon coverage was very small in the portion not covered by carbon and most of the surface was covered by carbon. Was confirmed.

The BET specific surface area of the attapulgite complex was measured based on the nitrogen adsorption capacity in the same manner as in Production Example 1. As a result, the BET specific surface area of the attapulgite complex was 30 m ² / g. Further, the volume average particle diameter of the attapulgite complex was measured in the same manner as in Production Example 1. As a result, the volume average particle diameter was 3.0 μm.

[Evaluation 2]
The metal ion adsorption capacity of the zeolite complex, allophane complex, kaolin complex, saponite complex, montmorillonite complex and attapulgite complex obtained in Example 3 to Example 8 was evaluated as follows. For comparison, synthetic imogolite before carbon coating (sample A), zeolite, allophane, kaolin, saponite, montmorillonite, attapulgite, the above-mentioned calcined product A and acetylene black (HS-100, electric chemical industry corporation) are used. It was.

An electrolyte containing 1 M of LiPF ₆ and ethylene carbonate (EC): dimethyl carbonate (DMC): diethyl carbonate (DEC) in a volume ratio of 1: 1: 1 was prepared, and this was prepared with Mn (BF ₄ ) ₂ Dissolve to prepare a 500 ppm Mn solution. After adding 0.05 g of each sample to this Mn solution and stirring for 30 minutes, it was allowed to stand at room temperature overnight. Thereafter, the supernatant was filtered using a filter with a pore size of 0.45 μm, and the adsorption amount of Mn ions was measured using an ICP emission spectrometer (ICP-AES). The results are shown in Table 4. In Table 4, the results for imogolite complex A and imogolite complex B obtained in Example 1 and Example 2 are also listed.

As can be seen from Table 4, not only imogolite complex A and imogolite complex B, but also zeolite complex, allophane complex, kaolin complex, saponite complex, montmorillonite complex and attapulgite complex, metal ion adsorption ability It has been shown.

Thus, the metal ion adsorption ability of imogolite complex A and imogolite complex B was maintained similarly to imogolite before carbon provision. In addition, the metal ion adsorption ability was maintained in the complex after the carbon application also for the zeolite complex, the kaolin complex, the allophane complex, the saponite complex, the montmorillonite complex and the attapulgite complex. The fact that the conductivity is imparted by carbon deposition is the result of Evaluation 1 on imogolite complex A, imogolite complex B, zeolite complex, kaolin complex, allophane complex, saponite complex, montmorillonite complex and attapulgite complex. It is clear from (see Table 3).
From these facts, all of the imogolite complex A, the imogolite complex B, the zeolite complex, the allophane complex, the kaolin complex, the saponite complex, the montmorillonite complex and the attapulgite complex can be used as a conductive material by using lithium. It has been found that the electrical characteristics and life characteristics of the ion secondary battery can be improved.

  Therefore, the aluminum silicate complex in the present invention exhibits both the ion exchange ability by Si and Al and the conductivity by carbon, and the conductive material containing aluminum silicate is a lithium ion secondary battery. It can be seen that the electrical characteristics and the life characteristics of the The present invention can provide a conductive material capable of improving the electrical characteristics and the life characteristics of a lithium ion secondary battery.

[Evaluation 3]
Charge-discharge characteristics and storage of the zeolite complex, allophane complex, kaolin complex, saponite complex, montmorillonite complex and attapulgite complex obtained in Examples 3 to 8 in the same manner as in the above [Evaluation 1] The trial was evaluated.

  The initial discharge capacity of zeolite, allophane, kaolin, saponite, montmorillonite or attapulgite is 0.3 mAh / g to 0.4 mAh / g, whereas carbon-coated zeolite complex, allophane complex, kaolin complex The first discharge capacity of the saponite complex, montmorillonite complex or attapulgite complex was 220 mAh / g to 280 mAh / g, and it was found to have equal or higher performance compared to 205 mAh / g of acetylene black .

  Regarding the capacity retention rate, cells C-3, C-4, C-5, C-6, in which a zeolite complex, allophane complex, kaolin complex, saponite complex, montmorillonite complex or attapulgite complex is used as a positive electrode. C-7 or C-8 was produced and evaluated, respectively. The capacity retention rate is improved by 5% in cell C-3, 5% in cell C-4, 3% in cell C-5, and 3% in cell C-6 with respect to the standard cell described above. The cell C-7 improved 5%, and the cell C-8 improved 5%.

  In addition, cells A-3, A-4, A-5, A-6, A-7 in which a zeolite complex, an allophane complex, a kaolin complex, a saponite complex, a montmorillonite complex or an attapulgite complex is used as a negative electrode. Or A-8 was each produced and evaluated. The capacity retention rate is improved by 0.5% in the cell A-3, 0.5% in the cell A-4, and 0.3% in the cell A-5, as compared with the standard cell described above. In -6, it improved 0.3%, in cell A-7 it improved 0.5%, and in cell A-8 it improved 0.5%.

  From this, it was found that adding various aluminum silicate composites to the negative electrode or positive electrode of the lithium ion secondary battery improves the capacity retention rate as compared to the case where the aluminum silicate composite is not added. .

  Therefore, the aluminum silicate complex in the present invention shows both the ion exchange ability by Si and Al and the conductivity by carbon, and the aluminum silicate complex in the present invention is a lithium ion secondary battery. It is understood that the electrical characteristics and the life characteristics of the lithium ion secondary battery can be improved by adding to the electrode (at least one of the positive electrode and the negative electrode).

10 Imogolite 10a Tubular 20 Inner Wall 30 Clearance 40 Carbon 50 Aluminum Silicate

Claims (10)

With aluminum silicate,
Carbon disposed on the surface of the aluminum silicate,
An electrically conductive material for a lithium ion secondary battery, comprising an aluminum silicate composite having:   The conductive material for a lithium ion secondary battery according to claim 1, wherein a carbon content ratio in the aluminum silicate composite is 0.1% by mass to 50% by mass.   The conductive material for a lithium ion secondary battery according to claim 1 or 2, wherein an R value obtained from Raman spectrum analysis of the aluminum silicate complex is 0.1 to 5.0.   The powder resistivity of the said aluminum silicate complex is 0.001 ohm * cm-100 ohm * cm, The electrically-conductive material for lithium ion secondary batteries of any one of Claims 1-3.   The lithium ion according to any one of claims 1 to 4, wherein the element molar ratio Si / Al of silicon (Si) to aluminum (Al) in the aluminum silicate composite is 0.1 to 500. Conductive material for secondary batteries.   The composition for lithium ion secondary battery negative electrode formation containing the electrically conductive material for lithium ion secondary batteries of any one of Claims 1-5, a negative electrode active material, and a binder.   The composition for lithium ion secondary battery positive electrode formation containing the electrically conductive material for lithium ion secondary batteries of any one of Claims 1-5, a positive electrode active material, and a binder. Current collector,
A negative electrode layer provided on the current collector and containing the conductive material for a lithium ion secondary battery according to any one of claims 1 to 5 and a negative electrode active material,
A negative electrode for a lithium ion secondary battery having the Current collector,
A positive electrode layer provided on the current collector and containing the conductive material for a lithium ion secondary battery according to any one of claims 1 to 5 and a positive electrode active material,
The positive electrode for lithium ion secondary batteries which has.   A lithium ion secondary battery comprising at least one of the negative electrode for a lithium ion secondary battery according to claim 8 and the positive electrode for a lithium ion secondary battery according to claim 9.