WO2012057341A1 - Silicate compound, secondary-battery positive electrode, secondary battery, and manufacturing methods therefor - Google Patents

Silicate compound, secondary-battery positive electrode, secondary battery, and manufacturing methods therefor Download PDF

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WO2012057341A1
WO2012057341A1 PCT/JP2011/075000 JP2011075000W WO2012057341A1 WO 2012057341 A1 WO2012057341 A1 WO 2012057341A1 JP 2011075000 W JP2011075000 W JP 2011075000W WO 2012057341 A1 WO2012057341 A1 WO 2012057341A1
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formula
compound
silicic acid
composition represented
group
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PCT/JP2011/075000
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French (fr)
Japanese (ja)
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義久 別府
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旭硝子株式会社
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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B33/00—Silicon; Compounds thereof
    • C01B33/20—Silicates
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H01M4/1391—Processes of manufacture of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a silicate compound, a positive electrode for a secondary battery, a secondary battery, and a method for producing them.
  • Patent Document 1 includes k Li in the unit formula, and [SiO 4 ], [SO 4 ], [PO 4 ], [GeO 4 ], [VO 4 ], [AlO 4 ], [BO]. 4 ] and the like, and compounds having an orthosilicate structure, which have a wide general formula, have been proposed as electrode materials.
  • Li 2 FeSiO 4 described in Non-Patent Document 1 is manufactured by a solid-phase reaction, the manufacturing process is complicated and the manufacturing cost increases.
  • Li 1.7 Mn 0.7 Fe 0.3 Si 0.7 P 0.3 O 4 that is actually disclosed as an electrode material in Patent Document 1 as a compound containing Si.
  • Li 2 MnSiO 4 and LiFePO 4 are mixed and pulverized, sealed in a tube, and heated to produce the solid phase reaction.
  • the solid-phase reaction has a complicated manufacturing process, is expensive to manufacture, is difficult to mass-produce, and composition control is not easy.
  • the object of the present invention is to control the composition and particle size of silicic acid compounds capable of increasing the capacity per unit mass, more specifically silicic acid-boric acid compounds and silicic acid-boric acid-phosphoric acid compounds. It is in providing a manufacturing method that is easy to do.
  • the compound is useful as an active material used for a positive electrode for a secondary battery and a positive electrode for a secondary battery.
  • the present invention also provides a positive electrode for a secondary battery having excellent characteristics and reliability and a method for producing the secondary battery.
  • a 2-d + a M b Si 1-d D d O 4-d + c1 (In the formula, element A is at least one element selected from the group consisting of Li, Na and K, and element M is at least one element selected from the group consisting of Fe, Mn, Co and Ni, D is B, or B and P, a is ⁇ 0.1 ⁇ a ⁇ 0.4, b is 0.7 ⁇ b ⁇ 1.3, and d is 0 ⁇ d ⁇ 0. 7 and c1 is a number that depends on the valence N of a, b, and M, and is a number that becomes c2 after the heating step.) D may be 0 ⁇ d ⁇ 0.7.
  • a 2-d + a M b Si 1-d D d O 4-d + c2 (B) (In the formula, A, M, D, a, b, and d have the same meanings as described above, but are independent values, and c2 is a number that depends on the valence N of a, b, and M. .)
  • the melt having the composition represented by the formula (A) is a melt having the composition represented by the following formula (1)
  • the silicic acid having the composition represented by the formula (B) The method for producing a silicic acid compound according to [1], wherein the compound is a silicic acid-boric acid compound having a composition represented by the following formula (2).
  • a 2-x + a M b Si 1-x B x O 4-x + c11 (1)
  • x is 0 ⁇ x ⁇ 0.7
  • c11 is a number that depends on the valence N of a, b, and M.
  • c12 is a number that depends on the valence N of a, b, and M.
  • the melting step includes The compound containing element A is A carbonate, A bicarbonate, A hydroxide, A silicate, A phosphate, A hydrogen phosphate, A borate, A Nitrate, A chloride, A sulfate, A acetate, and A oxalate, wherein at least one or all of the one or more are hydrated.
  • a salt may be formed.
  • the compound containing element M is M oxide, M oxyhydroxide, M silicate, M borate, M metal, M phosphate, M chloride, M nitrate, Included as at least one selected from the group consisting of M sulfate and M organic salt;
  • a compound containing Si is included as at least one selected from the group consisting of silicon oxide, A silicate, M silicate, and silicon alkoxide,
  • the compound containing B is included as at least one selected from the group consisting of boron oxide, boric acid, A borate and M borate.
  • the melt having the composition represented by the formula (A) is a melt having the composition represented by the following formula (3), and the silicic acid having the composition represented by the formula (B)
  • a 2-x-y + a M b Si 1- (x + y) B x P y O 4-x + c21 (3)
  • A, M, a, and b each have the same meaning as described above, x is 0 ⁇ x ⁇ 0.7, y is 0 ⁇ y ⁇ 0.7, and 0 ⁇ (x + y ) ⁇ 0.7
  • c21 is a number that depends on the valence N of a, b, and M, and is
  • the melting step includes The compound containing element A is A carbonate, A bicarbonate, A hydroxide, A silicate, A phosphate, A hydrogen phosphate, A borate, A Nitrate, A chloride, A sulfate, A acetate, and A oxalate, wherein at least one or all of the one or more are hydrated.
  • a salt may be formed.
  • the compound containing element M is M oxide, M oxyhydroxide, M silicate, M borate, M metal, M phosphate, M chloride, M nitrate, Included as at least one selected from the group consisting of M sulfate and M organic salt;
  • a compound containing Si is included as at least one selected from the group consisting of silicon oxide, A silicate, M silicate, and silicon alkoxide,
  • a compound containing B is included as at least one selected from the group consisting of boron oxide, boric acid, A borate, M borate and boron phosphate;
  • the compound containing P consists of phosphorus oxide, ammonium phosphate, ammonium hydrogen phosphate, boron phosphate, phosphoric acid, polyphosphoric acid, phosphorous acid, hypophosphorous acid, A phosphate and M phosphate Included as at least one selected from the group, [4] The method for producing a silicic acid compound according to [4], where
  • the melt having the composition represented by the formula (1) is a melt having the composition represented by the following formula (5A), and the silicic acid having the composition represented by the formula (2)
  • the melt having the composition represented by the formula (3) is a melt having the composition represented by the following formula (6A), and the silicic acid having the composition represented by the formula (4)
  • the solidified product includes at least one carbon source selected from the group consisting of an organic compound and carbon powder, and a ratio of a carbon conversion amount (mass) in the carbon source is
  • a ratio of a carbon conversion amount (mass) in the carbon source is The method for producing a silicic acid compound according to [1] to [10], wherein the mass is 0.1 to 20% by mass relative to the total mass of the mass of the solidified product and the carbon conversion amount (mass) in the carbon source.
  • the method for producing a silicate compound according to [1] to [11] wherein the heating step is performed by heating to 500 to 1,000 ° C.
  • element A is at least one element selected from the group consisting of Li, Na and K
  • element M is at least one element selected from the group consisting of Fe, Mn, Co and Ni
  • a is ⁇ 0.1 ⁇ a ⁇ 0.4
  • b is 0.7 ⁇ b ⁇ 1.3
  • x is 0 ⁇ x ⁇ 0.7
  • c12 is a, b, and M
  • element A is at least one element selected from the group consisting of Li, Na and K
  • element M is
  • the production method of the present invention is useful as an electrode material because it is easy to control the composition, particle size and uniformity of the silicate compound, and can efficiently produce silicate compounds having various compositions.
  • the silicic acid compound of the present invention is a compound showing a multi-electron type reaction. Therefore, by using the silicate compound of the present invention, a positive electrode material for a secondary battery and a secondary battery that are excellent in characteristics and reliability can be manufactured. Furthermore, the present invention provides a silicate compound.
  • FIG. 3 is a diagram showing X-ray diffraction patterns of silicic acid-boric acid compounds produced in Examples 1, 2, 3, and 4.
  • FIG. 4 is a diagram showing an X-ray diffraction pattern of silicic acid-boric acid compounds produced in Examples 5, 6, and 7.
  • FIG. 6 is a view showing an X-ray diffraction pattern of silicic acid-boric acid compounds produced in Examples 8, 9, and 10.
  • FIG. 3 is a diagram showing an X-ray diffraction pattern of silicic acid-boric acid-phosphoric acid compounds produced in Examples 18, 19, 20, and 21.
  • FIG. 3 is a diagram showing an X-ray diffraction pattern of silicic acid-boric acid-phosphoric acid compounds produced in Examples 22, 23, 24, and 25.
  • FIG. 1 is a diagram showing X-ray diffraction patterns of silicic acid-boric acid compounds produced in Examples 1, 2, 3, and 4.
  • FIG. 4 is a diagram showing an X-ray diffraction pattern of
  • FIG. 3 is a diagram showing an X-ray diffraction pattern of silicic acid-boric acid-phosphoric acid compounds produced in Examples 30, 31, and 33.
  • FIG. 4 is a diagram showing an X-ray diffraction pattern of silicic acid-boric acid compounds produced in Examples 36, 37, 38, and 39.
  • ⁇ Method for producing silicic acid compound> In the method for producing a silicate compound of the present invention, the following steps of the melting step (P1), the cooling step (P2), the pulverizing step (P3), and the heating step (P4) are performed in this order. Other steps may be performed before, between, and after the steps (P1) to (P4) as long as each step is not affected.
  • Melting step (P1) a step of obtaining a melt having a composition represented by the formula A 2-d + a M b Si 1-d D d O 4-d + c1 (wherein the symbols have the same meaning as described above), Cooling step (P2): a step of cooling the melt to obtain a solidified product, Crushing step (P3): crushing the solidified product to obtain a pulverized product, and heating step (P4): heating the pulverized product to obtain the formula A 2-d + a Mb Si 1-d D d O 4-d + c2 (The symbol in a formula shows the same meaning as the above.)
  • the process of obtaining the silicic acid which has a composition represented.
  • the method for producing a silicic acid compound of the present invention is specifically represented as the following methods for producing a silicic acid-boric acid compound and methods for producing a silicic acid-boric acid-phosphoric acid compound.
  • the following steps of the melting step (P11), the cooling step (P12), the pulverizing step (P13), and the heating step (P14) are performed in this order. Other steps may be performed before, between, and after the steps (P11) to (P14) as long as each step is not affected.
  • Melting step (P11) a step of obtaining a melt having a composition represented by the formula A 2-x + a M b Si 1-x B x O 4-x + c11 (wherein the symbols have the same meanings as described above), Cooling step (P12): a step of cooling the melt to obtain a solidified product, Milling step (P13): obtaining a ground product was pulverized said solidified product, and the heating step (P14): by heating the ground product of the formula A 2-x + a M b Si 1-x B x O 4-x + c12 A step of obtaining a silicic acid-boric acid compound having a composition represented by the formula:
  • the method for producing a silicic acid-boric acid-phosphoric acid compound of the present invention comprises the following steps in this order: a melting step (P21), a cooling step (P22), a pulverizing step (P23), and a heating step (P24). Do. Other steps may be performed before, between, and after the steps (P21) to (P24) as long as each step is not affected.
  • each step will be specifically described.
  • the melting step (P11) in the method for producing a silicic acid-boric acid compound of the present invention is a step of obtaining a melt represented by the following formula (1).
  • a 2-x + a M b Si 1-x B x O 4-x + c11 (1) (The symbols in the formula have the same meaning as described above.)
  • a raw material formulation prepared by adjusting raw materials including element sources (element A, element M, Si, and B) to have a composition represented by formula (1) is prepared first. preferable.
  • a is in the range of ⁇ 0.1 ⁇ a ⁇ 0.4 and b is in the range of 0.7 ⁇ b ⁇ 1.3.
  • a silicic acid-boric acid compound having a target composition can be produced by setting a and b in the raw material formulation within the above ranges. In addition, the raw material formulation can be melted well, and a uniform melt can be obtained. In addition, by setting x to 0 ⁇ x ⁇ 0.7, silicic acid that causes a multi-electron type reaction (reaction that pulls out more than 1 mol per unit mole) when used as a positive electrode material for a secondary battery A boric acid compound can be produced and the theoretical electric capacity of the secondary battery can be increased.
  • x may be 0 ⁇ x ⁇ 0.7.
  • a and b can cause a multi-electron type reaction more easily, so that ⁇ 0.1 ⁇ a ⁇ 0.3 and 0.8 ⁇ b ⁇ 1.3 are more preferable. preferable.
  • 0 ⁇ a ⁇ 0.3 and 1.0 ⁇ b ⁇ 1.3 there is a great effect of increasing the theoretical electric capacity within a range in which the structural change of the silicic acid-boric acid compound due to charge / discharge does not occur. There is.
  • the value of c11 is a number that depends on the valence N of a, b, and M. Since the valence of the element in the composition formula can be changed in the subsequent pulverization step and / or heating step, c11 is adjusted to a value that becomes c12 after the heating step. For example, when the value of c11 increases / decreases due to oxidation / reduction or volatilization of components in the heating process, it is preferable to set the value taking into account the increase / decrease. In the production method of the present invention, c11 is preferably 0.9 to 1.2 times the value of c12 of the target product.
  • the element A in the formula (1) is at least one element selected from the group consisting of Li, Na, and K. Since the element A is suitable as a positive electrode material for a secondary battery, it is preferable to make Li essential, and it is particularly preferable to use only Li.
  • the silicic acid-boric acid compound containing Li increases the capacity per unit volume (mass) of the secondary battery.
  • the element M in the formula (1) is at least one element selected from the group consisting of Fe, Mn, Co, and Ni.
  • the element M is preferably composed of only one kind or two kinds.
  • the element M consists of only Fe, Mn alone, or Fe and Mn. This is preferable in terms of cost.
  • the valence N of the element M is a numerical value that can change in each step of the production method of the present invention, and is in the range of +2 to +4.
  • the valence N is +2, +8/3 or +3 when the element M is Fe, +2, +3 or +4 when Mn, +2, +8/3 or +3 when Co and +2 or when Ni +4 is preferred.
  • the valence N is more preferably +2 in order to simplify the melting process.
  • the melting step (P21) in the method for producing a silicic acid-boric acid-phosphoric acid compound of the present invention is a step of obtaining a melt represented by the following formula (3).
  • a raw material formulation prepared by adjusting a raw material containing an element source (element A, element M, Si, B, and P) to have a composition represented by formula (3) is prepared. Is preferred.
  • a is in the range of ⁇ 0.1 ⁇ a ⁇ 0.4
  • b is in the range of 0.7 ⁇ b ⁇ 1.3.
  • x and y within this range, a silicic acid-boric acid-phosphoric acid compound that causes a multi-electron type reaction (reaction that pulls out more than 1 mol per mol) used as a positive electrode material for a secondary battery
  • the theoretical electric capacity of the secondary battery can be increased.
  • x may be 0 ⁇ x ⁇ 0.7
  • y may be 0 ⁇ y ⁇ 0.7
  • a and b can easily cause a multi-electron type reaction, so that ⁇ 0.1 ⁇ a ⁇ 0.3 and 0.8 ⁇ b ⁇ 1.3 are more preferable. preferable. Further, when 0 ⁇ a ⁇ 0.3 and 1.0 ⁇ b ⁇ 1.3, the effect of increasing the theoretical electric capacity within a range in which the structural change of the silicic acid-boric acid-phosphoric acid compound due to charge / discharge does not occur. There are great advantages.
  • the value of c21 is a number that depends on the valence N of a, b, and M. Since the valence of the element in the composition formula can be changed in the subsequent pulverization step and / or the heating step, c21 is adjusted to a value that becomes c22 after the heating step. For example, when the value of c21 increases or decreases due to oxidation / reduction or volatilization of the components in the heating step, it is preferable to set the value in consideration of the increase / decrease. In the production method of the present invention, c21 is preferably set to a value 0.9 to 1.2 times the target c22.
  • the preferable range of the element A in the formula (3) is the same as the preferable range of the element A in the formula (1).
  • the preferable range of the element M in the formula (3) is the same as the preferable range of the element M in the formula (1).
  • melting in the melting step can be facilitated by setting the composition of the raw material formulation to a specific range.
  • the formula (1) in the melting step (P11) and the formula (3) in the melting step (P21) have been described, the same applies to the formula (A) in the melting step (P1). That is, the preferable ranges of a and b in the formula (A) are the same as the preferable ranges of a and b in the formula (1) or a and b in the formula (3), and the preferable range of c1 in the formula (A) is , C11 in formula (1) or c21 in formula (3) is the same as the preferred range, and d in formula (A) is preferably x in formula (1) or x + y in formula (3). It is the same.
  • the preferable range of the element A of Formula (A) is the same as the preferable range of the element A of Formula (1).
  • the preferable range of the element M of the formula (A) is the same as the preferable range of the element M of the formula (1).
  • the compound containing element A in the raw material formulation includes A carbonate (A 2 CO 3 ), A hydrogen carbonate (AHCO 3 ), A hydroxide (AOH), and A silicate (A 2 O ⁇ 2SiO 2 , A 2 O ⁇ SiO 2 , 2A 2 O ⁇ SiO 2, etc., A phosphate (A 3 PO 4 ), A hydrogen phosphate (A 2 HPO 4 , AH 2 PO 4 etc.) ), A borate (A 2 O ⁇ B 2 O 3 , A 2 O ⁇ 2B 2 O 3 , A 2 O ⁇ 4B 2 O 3, etc.), A nitrate (ANO 3 ), A chloride ( ACl), sulfate of A (A 2 SO 4 ), organic acid salt of A (acetate (CH 3 COOA) and oxalate ((COOA) 2 ), etc.) are preferred. .
  • the element A is preferably Li. Furthermore, these compounds may be hydrates. Of these compounds may be hydrates. Of these compounds may
  • the compound containing the element M is at least selected from the group consisting of Fe 3 O 4 , Fe 2 O 3 , MnO, Mn 2 O 3 , MnO 2 , Co 3 O 4 , and NiO because of availability and cost.
  • One type is more preferable, and at least one selected from the group consisting of Fe 3 O 4 , Fe 2 O 3 , and MnO 2 is particularly preferable.
  • Fe 3 O 4 , Fe 2 O 3 , and MnO 2 may be used alone or in combination of two or more.
  • the compound containing Si in the raw material preparation includes silicon oxide (SiO 2 ), A silicate, M silicate, and silicon alkoxide (Si (OCH 3 ) 4 , Si (OC 2 H 5 ) 4. Etc.) is preferred, and silicon oxide is particularly preferred because it is inexpensive.
  • the compound containing Si may be crystalline or amorphous.
  • Compounds containing B in the raw material formulation include boron oxide (B 2 O 3 ), boric acid (H 3 BO 3 ), A borate, M borate, and boron phosphate (B 2 O 3). • At least one selected from the group consisting of P 2 O 5 ) is preferable, and at least one selected from the group consisting of boron oxide and boric acid is particularly preferable because it is inexpensive.
  • At least one selected from the group consisting of ammonium hydrogen phosphate and boron phosphate is more preferable.
  • the phosphate of A is preferably Li 3 PO 4
  • the phosphate of M is at least 1 selected from the group consisting of Fe 3 (PO 4 ) 2 , FePO 4 , and Mn 3 (PO 4 ) 2. Species are preferred.
  • the raw material preparation includes a carbonate or hydrogen carbonate of A; an oxide of M or an oxyhydroxide of element M; a silicon oxide; and a combination of boron oxide or boric acid Is preferred.
  • Still raw material formulation Li 2 CO 3 or LiHCO 3; combination of and B 2 O 3; Fe 3 O 4, Fe 2 O 3, and one or more compounds selected from the group consisting of MnO 2; SiO 2 Is particularly preferred.
  • raw material preparations include A carbonate or hydrogen carbonate; M oxide or element M oxyhydroxide; silicon oxide; boron oxide, boron A combination of acid or boron phosphate; and ammonium hydrogen phosphate or boron phosphate is preferred.
  • Still raw material formulation Li 2 CO 3 or LiHCO 3; Fe 3 O 4, Fe 2 O 3, and one or more compounds selected from the group consisting of MnO 2; SiO 2; B 2 O 3; NH 4 A combination of H 2 PO 4 is particularly preferred.
  • the composition of the raw material formulation corresponds to the composition of the melt in the production of the silicic acid-boric acid compound and the silicic acid-boric acid-phosphoric acid compound.
  • the composition of the obtained melt is the same as the composition of the raw material formulation. There may be differences. In such a case, it is preferable to appropriately change the composition of the raw material formulation in consideration of the amount lost due to volatilization or the like.
  • the purity of each raw material included in the raw material preparation is not particularly limited. Considering reactivity, characteristics of the positive electrode material for secondary batteries, and the like, the purity excluding hydrated water is preferably 99% by mass or more.
  • the melting step in the present invention is a step of obtaining a melt having a composition represented by formula (B), a composition represented by formula (1), or a composition represented by formula (3).
  • This step is preferably carried out by heating and melting the raw material formulation.
  • each raw material or raw material preparation Prior to melting, each raw material or raw material preparation is preferably pulverized and / or mixed dry or wet using a mixer, ball mill, jet mill, planetary mill or the like.
  • the particle size of the raw material in each raw material preparation is not limited as long as it does not adversely affect the mixing operation, the filling operation of the raw material preparation into the melting container, the meltability of the raw material preparation, and the like.
  • the container is preferably made of alumina, carbon, silicon carbide, zirconium boride, titanium boride, boron nitride, carbon, platinum, or a platinum alloy containing rhodium.
  • a container made of a refractory-based brick and a reducing material (eg, graphite) can also be employed.
  • a lid to the container and melt it.
  • the heating furnace is preferably a resistance heating furnace, a high frequency induction furnace, or a plasma arc furnace.
  • the resistance heating furnace is preferably an electric furnace provided with a heating element made of an alloy such as a nichrome alloy, silicon carbide, or molybdenum silicide.
  • the melting step is preferably performed in air, in an inert gas, or in a reducing gas. Melting conditions can be changed as appropriate depending on conditions such as the type of container or heating furnace and the heating method such as a heat source.
  • the pressure may be any of normal pressure, pressurization, and reduced pressure (0.9 ⁇ 10 5 Pa or less). Although it is preferably in reducing gas, it may be in oxidizing gas. If it is in the oxidizing gas, reduction (for example, change from M 3+ to M 2+ ) can be performed in the heating step of the next step.
  • the inert gas is a gas containing 99% by volume or more of at least one inert gas selected from the group consisting of nitrogen gas (N 2 ) and rare gases such as helium gas (He) and argon gas (Ar). It is a condition.
  • the term “in the reducing gas” refers to a gas condition in which a reducing gas is added to the inert gas and substantially does not contain oxygen. Examples of the reducing gas include hydrogen gas (H 2 ), carbon monoxide gas (CO), and ammonia gas (NH 3 ).
  • the amount of the reducing gas in the inert gas is preferably 0.1% by volume or more, and particularly preferably 1 to 10% by volume of the reducing gas in the total gas.
  • the oxygen content in the gas is preferably 1% by volume or less, particularly preferably 0.1% by volume or less.
  • the heating temperature in the melting step is preferably 1,300 to 1,600 ° C., particularly preferably 1,400 to 1,550 ° C.
  • melting means that each raw material is melted and is in a transparent state visually.
  • the heating time is preferably 0.2 to 2 hours, particularly preferably 0.5 to 2 hours. By setting the time, the homogeneity of the melt is sufficient, and the raw material is difficult to volatilize.
  • stirring may be performed to increase the uniformity of the melt.
  • the melt may be clarified at a temperature lower than the heating temperature until the next cooling step is performed. Further, the melt obtained in the melting step may be subjected to other steps before the cooling step as long as it does not adversely affect the next cooling step.
  • the cooling step is a step of obtaining a solidified product by cooling the melt obtained in the melting step to near room temperature.
  • the solidified product is preferably an amorphous material, but a part of the solidified product may be a crystallized product.
  • the next pulverization step can be easily performed, and the composition and particle size of the silicate compound can be easily controlled. Furthermore, there is an advantage that the product can be prevented from being agglomerated in the subsequent heating step, and the particle size of the product can be easily controlled.
  • the crystallized product becomes a crystal nucleus in the heating step in the subsequent step, and crystallization is facilitated.
  • the amount of crystallized product in the solidified product is preferably 0 to 30% by mass with respect to the total mass of the solidified product.
  • the cooling step is preferably performed in air from the viewpoint of equipment and the like.
  • the cooling step may be performed in an inert gas or a reducing gas.
  • the cooling rate of the melt is preferably not less than -1 ⁇ 10 3 °C / sec, -1 ⁇ 10 4 °C / sec or more is particularly preferable.
  • a temperature change per unit time (ie, cooling rate) in the case of cooling is indicated by a negative value
  • a temperature change per unit time in case of heating ie, the heating rate
  • the cooling rate is higher than this value, an amorphous material is easily obtained.
  • the upper limit of the cooling rate is preferably about ⁇ 1 ⁇ 10 10 ° C./second from the viewpoint of manufacturing equipment and mass productivity, and is particularly preferably ⁇ 1 ⁇ 10 8 ° C./second from the viewpoint of practicality.
  • the cooling rate of the melt is particularly preferably from -10 3 ° C / second to -10 10 ° C / second from 1000 ° C to 50 ° C.
  • the method of cooling the melt is, for example, a method in which a melt is dropped between twin rollers rotating at high speed to obtain a flake-like solidified product, or a melt is dropped on a rotating single roller to form a flake-like or plate-like solidified product. It is preferable that the method is obtained by sweeping an object, or a method in which a melt is pressed on a cooled carbon plate or metal plate to obtain a lump solidified product. Among these, a cooling method using twin rollers is more preferable because the cooling rate is high and a large amount of processing can be performed. As the double roller, it is preferable to use one made of metal, carbon, or ceramic.
  • a cooling method there is a method in which the melt is directly poured into water, but this method is difficult to control, and the cooling rate is about ⁇ 1 ⁇ 10 ° C./second to ⁇ 1 ⁇ 10 2 ° C./second. Difficult to obtain crystalline material. Further, the solidified product becomes a lump and requires a lot of labor for pulverization.
  • a cooling method there is also a method in which a melt is directly charged into liquid nitrogen, and the cooling rate can be made faster than in the case of water.
  • problems similar to the method using water and the cost is high.
  • the solidified product obtained in the cooling step is preferably flaky or fibrous.
  • the flaky solidified product preferably has an average thickness of 200 ⁇ m or less, particularly preferably 100 ⁇ m or less.
  • the average diameter of the plane perpendicular to the average thickness as the flaky solidified product is not particularly limited.
  • the fibrous solidified product preferably has an average diameter of 50 ⁇ m or less, particularly preferably 30 ⁇ m or less.
  • the average thickness and average diameter can be measured with a caliper or a micrometer. The average diameter can also be measured by microscopic observation.
  • the solidified product obtained in the cooling step may be subjected to another step before the pulverization step as long as it does not adversely affect the next pulverization step.
  • the pulverization step is a step of pulverizing the solidified product obtained in the cooling step to obtain a pulverized product. Since the solidified product usually contains a large amount of amorphous material or consists of an amorphous material, there is an advantage that it is easy to grind. Further, there is an advantage that grinding can be performed without imposing a burden on an apparatus used for grinding and the particle size can be easily controlled. On the other hand, in the conventional solid phase reaction, pulverization is performed after the heating step, but the present inventor has noticed that there is a problem that residual stress is generated by the pulverization and battery characteristics are deteriorated. Therefore, in the manufacturing method of the present invention, a method is adopted in which the residual stress generated by pulverization before the heating step is reduced or removed in the heating step in the subsequent step.
  • the pulverization is preferably performed using a jaw crusher, a hammer mill, a ball mill, a jet mill, a planetary mill or the like.
  • the method of pulverization may be either dry or wet. It is preferable to preliminarily make the solidified material fine by hitting it with a hammer or a hammer before the pulverization step, since the burden on the pulverization step is reduced.
  • the pulverization is performed in a wet manner, it is preferable to carry out the heating step after removing the dispersion medium by sedimentation, filtration, drying under reduced pressure, drying by heating, or the like.
  • the heating step may be carried out with the pulverized product containing the dispersion medium as it is.
  • the silicic acid compound in the present invention is an insulating material, when used as a positive electrode material for a secondary battery, it is preferable to include a conductive material in the solidified product. Moreover, when using as a positive electrode material for secondary batteries, it is preferable that it is a fine particle form.
  • the average particle diameter of the pulverized product is preferably 10 nm to 10 ⁇ m, and particularly preferably 10 nm to 5 ⁇ m, in terms of volume-based median diameter.
  • the particle size can be measured by a sedimentation method or a laser diffraction / scattering particle size measuring device. When the particle size of the pulverized product is small, the reduction reaction is promoted, and the heating temperature and time of the heating step can be reduced, which is preferable.
  • the conductive material is preferably at least one carbon source selected from the group consisting of organic compounds and carbon powder.
  • the amount of at least one carbon source selected from the group consisting of an organic compound and carbon powder is such that the carbon equivalent amount (mass) in the carbon source is the mass of the solidified product and the carbon equivalent amount (mass in the carbon source). ) In an amount of 0.1 to 20% by mass, particularly preferably 2 to 10% by mass.
  • the organic compound at least one selected from the group consisting of saccharides, amino acids, peptides, aldehydes, ketones, glycols, polyvinyl alcohol, and fatty acids is preferable, and saccharides, glycols, or polyvinyl alcohol is particularly preferable.
  • the saccharide include monosaccharides such as glucose, fructose, and galactose, oligosaccharides such as sucrose, maltose, cellobiose, and trehalose, invert sugar, polysaccharides such as dextrin, amylose, amylopectin, and cellulose, and ascorbic acid. It is done.
  • amino acids examples include amino acids such as alanine and glycine.
  • Peptides include low molecular weight peptides having a molecular weight of 1,000 or less.
  • carbon powder carbon black, graphite, acetylene black and the like are preferable.
  • the carbon powder may be fibrous carbon or plate-like carbon.
  • the pulverization step when the solidified product is pulverized with an organic compound or carbon powder, there is an advantage that the step of mixing the conductive material after the heating step can be omitted. Moreover, the organic compound and carbon powder can suppress the grain growth of the solidified product.
  • wet pulverization is preferably employed in order to uniformly disperse the pulverized product on the surface.
  • a dispersion medium for pulverization water or an organic solvent such as ethanol, isopropyl alcohol, acetone, hexane, or toluene can be used. Of these, water is preferable because it is inexpensive.
  • a dry method is preferable for the pulverization step when the solidified product contains carbon powder.
  • the pulverized product obtained in the pulverization step may be subjected to another step before the heating step as long as it does not adversely affect the next heating step.
  • the heating step is a step of heating the pulverized product obtained in the pulverization step.
  • a silicic acid-boric acid compound having a composition represented by the following formula (B) is obtained.
  • a 2-d + a M b Si 1-d D d O 4-d + c2 (B) (In the formula, A, M, D, a, b, and d have the same meaning as described above, but take an independent value from the value in formula (A), and c12 is the valence of a, b, and M. The number depends on N.)
  • a silicic acid-boric acid compound having a composition represented by the following formula (2) is obtained.
  • a 2-x + a M b Si 1-x B x O 4-x + c12 (2) (In the formula, A, M, a, b, and x have the same meaning as described above, but take a value independent of the value in the formula (1), and c12 represents the valence N of a, b, and M. Depends on the number.)
  • a silicic acid-boric acid-phosphoric acid compound having a composition represented by the following formula (4) is obtained.
  • A, M, a, b, x, and y have the same meaning as described above, but take an independent value from the value in formula (3), and c22 is the valence of a, b, and M. The number depends on N.
  • the product of the heating step is preferably crystal particles, and more preferably olivine type crystal particles. Since the heating step in the present invention heats the pulverized product, relaxation of residual stress is promoted. In addition, since the formation of crystal nuclei and grain growth are performed by heating, the composition, grain size, and distribution thereof are easier to control than those in the temperature lowering process.
  • the heating step when the organic compound and / or carbon powder is included in the solidified product in the pulverization step can be a step of bonding a conductive material to the surface of the product, preferably the crystal grains of the product.
  • the organic compound is thermally decomposed in the heating process, becomes a carbide, and can function as a conductive material.
  • the heating temperature in the heating step is preferably 500 to 1,000 ° C. When the heating temperature is 500 ° C. or higher, crystals are easily generated. When the heating temperature is 1,000 ° C. or less, melting of the pulverized product can be prevented.
  • the heating temperature is more preferably 600 to 900 ° C. When the heating temperature is used, crystal particles having appropriate crystallinity, particle diameter, particle size distribution, and the like are easily obtained, and olivine-type crystal particles are preferably obtained.
  • the pulverization process is performed in a wet manner, when the heating process is performed while the dispersion medium is included, the heating process can be a process of removing the dispersion medium.
  • the heating in the heating step may be performed at a constant temperature after the temperature is increased at once, or may be performed by changing the temperature in multiple stages. Since the particle diameter to be generated tends to increase as the heating temperature increases, the heating temperature is preferably set according to the desired particle diameter.
  • the heating time (holding time depending on the heating temperature) is preferably 1 to 72 hours in consideration of a desired particle size. Heating is preferably performed in a box furnace, tunnel kiln furnace, roller hearth furnace, rotary kiln furnace, microwave heating furnace, or the like that uses electricity, oil, gas, or the like as a heat source.
  • the heating step can be carried out in air, in an inert gas or in a reducing gas, and is preferably carried out in an inert gas or in a reducing gas.
  • the conditions in the inert gas and the reducing gas are the same as those in the melting step.
  • the heating step may be carried out under reduced pressure (0.9 ⁇ 10 5 Pa or less) in an inert gas or a reducing gas.
  • a reducing agent eg, graphite
  • pulverized material eg, change from M 3+ to M 2+
  • the cooling step after the heating step, it is usually cooled to room temperature.
  • the cooling rate in the cooling is preferably ⁇ 30 ° C./hour to ⁇ 300 ° C./hour. By setting the cooling rate within this range, distortion due to heating can be removed, and when the product is a crystal, the target product can be obtained while maintaining the crystal structure. Moreover, it can cool without using a cooling means.
  • the cooling is preferably allowed to cool to room temperature. Cooling is preferably performed in an inert gas or a reducing gas.
  • the silicic acid compound obtained by the production method of the present invention is a novel compound useful as a positive electrode material for secondary batteries.
  • the silicic acid compound in the present invention has a number of atoms of the element A of 1.2 or more, and therefore has a multi-electron type as compared with a case of less than 1.2, and is a unit when used as a positive electrode material for a secondary battery.
  • the capacity per mass increases. That is, when the element A is Li, the silicic acid-boric acid compound in the present invention has a structure containing more than one and not more than two Li per unit ([SiO 4 ] + [BO 4 ]) tetrahedron. Since this is a silicic acid-boric acid compound, the number of Li atoms can be 1.2 or more.
  • a silicic acid-boric acid compound in which [SiO 4 ] tetrahedron, [BO 4 ] tetrahedron, [LiO 4 ] tetrahedron and [MO 4 ] tetrahedron are uniformly distributed can be obtained.
  • the element A is Li
  • the silicic acid-boric acid-phosphoric acid compound has more than one and not more than two per unit ([SiO 4 ] + [BO 4 ] + [PO 4 ]) tetrahedron. Since a silicic acid-boric acid-phosphoric acid compound having a structure containing Li can be obtained, the number of Li atoms can be 1.2 or more.
  • [SiO 4 ] tetrahedron, [BO 4 ] tetrahedron, [PO 4 ] tetrahedron, [LiO 4 ] tetrahedron and [MO 4 ] tetrahedron are uniformly distributed.
  • a boric acid-phosphoric acid compound can be obtained.
  • the silicic acid-boric acid compound or silicic acid-boric acid-phosphoric acid compound preferably contains olivine type crystal particles.
  • the olivine type crystal particle is a material that exhibits a multi-electron type theoretical electric capacity.
  • the crystal particles include both primary particles and secondary particles. When secondary particles are present in the product, they may be crushed and pulverized as long as the primary particles are not destroyed.
  • a conductive material composed of carbon derived from the organic compound or carbon powder is uniformly formed on the surface of the silicic acid compound. And can be firmly bonded.
  • the silicic acid compound to which the conductive material is bonded can be used as it is for a positive electrode material for a secondary battery.
  • the composition of the silicic acid-boric acid compound produced by the production method of the present invention is a composition in which A is Li and M is at least one selected from the group consisting of Fe and Mn.
  • the compound represented by these is preferable.
  • m is particularly preferably 0 ⁇ m ⁇ 1.
  • Li 2-x + a (Fe m Mn 1-m ) b Si 1-x B x O 4-x + c12 (5) (The symbols in the formula have the same meaning as described above, and m is 0 ⁇ m ⁇ 1.)
  • composition of the silicic acid-boric acid-phosphoric acid compound produced by the production method of the present invention is a composition using at least one selected from the group consisting of A being Li and M being Fe and Mn.
  • the compound represented by Formula (6) is preferable.
  • m is particularly preferably 0 ⁇ m ⁇ 1.
  • the silicic acid-boric acid compound having the composition represented by the formula (2) is a crystal, it is preferably a solid solution crystal or a eutectic crystal.
  • a solid solution crystal is likely to be formed. The reason is considered that a part of Si is substituted with B by the formula represented by formula (7).
  • the silicic acid-boric acid compound in the present invention contains a silicic acid-boric acid compound in solid solution crystal
  • the silicic acid-boric acid compound contains olivine type crystal particles which are solid solution crystals in which a part of Si is substituted with B. Is preferred.
  • the silicic acid-boric acid compound is a solid solution crystal
  • Li ions easily move in the crystal, resulting in high capacity and increased electrical conductivity. To do. Therefore, when used as a positive electrode material for a secondary battery, a theoretical capacity is easily obtained, and it is considered that the charge / discharge cycleability is improved.
  • silicic acid-boric acid compound eutectic when x is 0.2 ⁇ x ⁇ 0.7, eutectic is likely to occur. It is preferable that 0.2 ⁇ x ⁇ 0.7.
  • the eutectic silicic acid-boric acid compound (hereinafter referred to as “silicic acid-boric acid compound eutectic”, or simply “eutectic”) includes a crystal containing a silicon atom, a crystal containing a boron atom, , A crystal in which crystals containing boron atoms and silicon atoms coexist.
  • a eutectic containing at least one selected from the group consisting of The eutectic is considered to be produced by the reaction mechanism represented by the following formula (8).
  • x and z are 0.2 ⁇ x ⁇ 0.7 and 0.2 ⁇ z ⁇ 0.8
  • the silicic acid-boric acid compound of the present invention is preferably a eutectic because the electric conductivity tends to increase.
  • the reason is that, due to the generation of crystallites having a plurality of crystal structures and different electrical conductivities, a potential difference is generated between the crystallites when a potential is applied. This is thought to be due to the rise.
  • a structure having a grain boundary is formed between the crystallites in the primary particle, and this grain boundary is extremely thin as compared with the inside of the primary particle, which is considered to be because the electrical conductivity of the primary particle itself is increased.
  • the silicic acid-boric acid compound of the present invention is particularly preferably an eutectic because it easily obtains high electrical conductivity and improves charge / discharge cycleability.
  • the silicic acid-boric acid compound of the present invention has a high capacity when the silicic acid-boric acid compound is applied to a positive electrode for a secondary battery, and solid solution crystals are particularly preferable in that good cycle characteristics are easily obtained.
  • eutectic is particularly preferable from the viewpoint that high electrical conductivity is easily obtained when applied to a positive electrode for a secondary battery.
  • the silicic acid-boric acid-phosphoric acid compound having the composition represented by the formula (4) is a crystal, it is preferably a solid solution crystal or a eutectic crystal.
  • x and y are 0 ⁇ (x + y) ⁇ 0.2, a solid solution crystal is likely to be formed.
  • the reason is considered that a part of Si is replaced by B and P by the formula represented by formula (9).
  • the silicic acid-boric acid-phosphoric acid compound in the present invention contains a solid solution crystalline silicic acid-boric acid-phosphoric acid compound, olivine type crystal particles which are solid solution crystals in which a part of Si is substituted with B and P
  • a silicic acid-boric acid-phosphoric acid compound containing When the silicic acid-boric acid-phosphoric acid compound is a solid solution crystal, when it is used as a positive electrode material for a secondary battery, Li ions easily move in the crystal, resulting in a high capacity and electrical conductivity. The degree rises. Therefore, when used as a positive electrode material for a secondary battery, a theoretical capacity is easily obtained, and it is considered that the charge / discharge cycleability is improved.
  • the eutectic silicic acid-boric acid-phosphoric acid compound includes a crystal containing a silicon atom, A crystal containing a boron atom, a crystal containing a phosphorus atom, and a crystal containing a phosphorus atom, a boron atom, and a silicon atom coexist.
  • a 2-p-q M b Si 1-p-q P p B q O 4-q (a and b are as defined above, p is 0.2 ⁇ p ⁇ 0.8 And q is 0.2 ⁇ q ⁇ 0.8, and p + q is 0.2 ⁇ p + q ⁇ 0.8.)
  • an olivine of A 2 MSiO 4 A eutectic containing at least one selected from the group consisting of a type crystal, an olivine type crystal of AMBO 3 and an olivine type crystal of AMPO 4 is preferable.
  • the silicic acid-boric acid-phosphoric acid compound is considered to be produced by the reaction mechanism represented by the following formula (10).
  • silicic acid-boric acid-phosphoric acid compound of the present invention is preferably an eutectic is the same as that of the silicic acid-boric acid compound.
  • the silicic acid-boric acid-phosphoric acid compound of the present invention is particularly preferably an eutectic because it is easy to obtain high electrical conductivity and charge / discharge cycleability is improved.
  • a silicic acid-boric acid-phosphoric acid compound of the present invention when the silicic acid-boric acid-phosphoric acid compound is applied to a positive electrode for a secondary battery, it has a high capacity and obtains good cycle characteristics.
  • a solid solution crystal is particularly preferable from the viewpoint of easiness, and a eutectic is particularly preferable from the viewpoint that high electrical conductivity is easily obtained when applied to a positive electrode for a secondary battery.
  • the average particle diameter of the silicate compound of the present invention is preferably an average particle diameter of 10 nm to 10 ⁇ m, more preferably 10 nm to 6 ⁇ m, and particularly preferably 10 nm to 2 ⁇ m in terms of volume median diameter.
  • the lower limit value may be 100 nm. By making the average particle diameter within this range, the conductivity becomes higher.
  • the average particle diameter can be determined by, for example, observation with an electron microscope or measurement with a laser diffraction particle size distribution meter.
  • the specific surface area of the silicate compound is preferably 0.2 ⁇ 200m 2 / g, preferably 0.5 ⁇ 200m 2 / g, 1 ⁇ 200m 2 / g is particularly preferred.
  • the upper limit value may be 100 m 2 / g or 10 m 2 / g.
  • the specific surface area can be measured by, for example, a specific surface area measuring apparatus using a nitrogen adsorption method.
  • the silicic acid compound obtained by the method for producing a silicic acid compound of the present invention is useful as a positive electrode material for a secondary battery. Therefore, the positive electrode for secondary batteries and a secondary battery can be manufactured using this silicate compound.
  • the secondary battery include a metal lithium secondary battery, a lithium ion secondary battery, and a lithium polymer secondary battery, and a lithium ion secondary battery is preferable.
  • the battery shape is not limited, and various shapes and sizes such as a cylindrical shape, a square shape, and a coin shape can be appropriately employed.
  • the production of the positive electrode for the secondary battery may be performed in accordance with a known electrode production method, except that the silicate compound obtained by the production method of the present invention is used.
  • the silicic acid compound of the present invention is added to a known binder (polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl chloride, ethylene propylene diene polymer, styrene-butadiene rubber, acrylonitrile-butadiene rubber, fluororubber, Obtained by mixing with polyvinyl acetate, polymethyl methacrylate, polyethylene, nitrocellulose, etc.) and, if necessary, known conductive materials (acetylene black, carbon, graphite, natural graphite, artificial graphite, needle coke, etc.).
  • the mixed powder may be pressure-formed on a support made of stainless steel or filled in a metal container.
  • the mixed powder is mixed with an organic solvent (N-methylpyrrolidone, toluene, cyclohexane, dimethylformamide, dimethylacetamide, methyl ethyl ketone, methyl acetate, methyl acrylate, diethyltriamine, NN-dimethylaminopropylamine, ethylene oxide, tetrahydrofuran.
  • the electrode can also be produced by a method such as applying a slurry obtained by mixing with a metal substrate such as aluminum, nickel, stainless steel or copper.
  • the positive electrode for a secondary battery obtained by the production method of the present invention is used as an electrode.
  • the negative electrode a known negative electrode active material can be used as the active material, but it is preferable to use at least one selected from the group consisting of a carbon material, an alkali metal material, and an alkaline earth metal material.
  • the electrolyte solution is preferably non-aqueous. That is, as the secondary battery obtained by the production method of the present invention, a nonaqueous electrolyte lithium ion secondary battery is preferable.
  • Lithium (Li 2 CO 3 ), sodium carbonate (Na 2 CO 3 ), triiron tetroxide (Fe 3 O 4 ), manganese dioxide (MnO 2 ), tricobalt tetroxide (Co 3 O 4 ), nickel oxide (NiO ), Silicon dioxide (SiO 2 ), and boron oxide (B 2 O 3 ) were weighed, mixed and pulverized by a dry method to obtain a raw material formulation.
  • Each raw material formulation was filled in a platinum alloy crucible containing 20% by mass of rhodium.
  • the crucible was placed in an electric furnace (manufactured by Motoyama, apparatus name: NH-3035) equipped with a heating element made of molybdenum silicide.
  • the temperature was raised at a rate of + 300 ° C./hour and heated at 1,400 to 1,500 ° C. for 0.5 hour.
  • Each melt was obtained after confirming that it became transparent visually.
  • the composition formula of the obtained melt is shown in the right column of Table 1.
  • the pulverized product obtained in the pulverization step was placed in a 3% by volume H 2 —Ar atmosphere, and each example was heated for 8 hours at four temperature conditions of 600 ° C., 700 ° C., 800 ° C., and 900 ° C.
  • the mixture was cooled (air cooled) at a rate of -200 ° C./hour to precipitate silicic acid-boric acid compound particles.
  • X-ray diffraction, particle size distribution, and composition analysis were performed on particles obtained by carrying out the heating step at 700 ° C.
  • the mineral phase of the obtained silicic acid-boric acid compound particles was measured using an X-ray diffraction apparatus (manufactured by Rigaku Corporation, apparatus name: RINT TTRIII).
  • the particles obtained in Examples 1 to 4 and Examples 8 to 17 are all orthorhombic olivine type Li 2 MSiO 4 (K. Zaghib et al., Journal of Power Sources, 160, 1381-1386, 2006 and R. Dominko et al., Electrochemistry Communications, 8, 217-222 (2006)). From the results, it was confirmed that the silicic acid-boric acid compound particles were crystals and a solid solution crystal in which a part of Si in the Li 2 MSiO 4 crystal was substituted with B.
  • Examples 5 to 7 diffraction patterns considered to be eutectics containing Li 2 MSiO 4 , LiMBO 3 , and solid solutions thereof were shown. From the results, it was confirmed that when x is 0.2 ⁇ x ⁇ 0.7, a eutectic containing Li 2 MSiO 4 , LiMBO 3 , and a solid solution thereof can be obtained.
  • the X-ray diffraction patterns of the crystals obtained in Examples 1, 2, 3, and 4 are respectively shown in (a), (b), (c), and (d) of FIG.
  • the X-ray diffraction patterns of the crystals obtained in Example 7 are shown in FIGS. 2 (a), (b), and (c), respectively. These are shown in FIGS. 3A, 3B, and 3C, respectively.
  • the particle size distribution of the silicic acid-boric acid compound obtained in Examples 2 and 9 was measured with a laser diffraction / scattering particle size distribution analyzer (manufactured by Horiba, Ltd., apparatus name: LA-920). The volume-converted median diameters were 2.5 ⁇ m (Example 2) and 2.8 ⁇ m (Example 9), respectively. Furthermore, when the specific surface area of the silicic acid-boric acid compound was measured with a specific surface area measuring apparatus (manufactured by Shimadzu Corporation, apparatus name: ASAP2020), all were 1.2 m 2 / g.
  • composition analysis The chemical composition of the resulting silicic acid-boric acid compound particles was measured. First, silicic acid-boric acid compound particles were decomposed by heating and sealing with a 2.5 mol / L KOH solution at 120 ° C., and the decomposition solution was dried under hydrochloric acid acidity. Next, after filtration as a hydrochloric acid acidic solution, a filtrate and a residue were obtained. The amounts of Si, B, Fe, Mn, Co, and Ni in the filtrate were quantified using an inductively coupled emission spectroscopic analyzer (manufactured by Seiko Instruments Inc., apparatus name: SPS3100).
  • the amounts of Li and Na in the filtrate were quantified using an atomic absorption photometer (manufactured by Hitachi High-Technologies Corporation, apparatus name: Z-2310).
  • the amounts of SiO 2 , B 2 O 5 , FeO, MnO, CoO, NiO, Li 2 O, and Na 2 O are calculated from the quantitative values of Si, B, Fe, Mn, Co, Ni, Li, and Na, respectively. did. Further, the residue was incinerated and then decomposed with hydrofluoric acid-sulfuric acid, and the weight loss due to this treatment was changed to SiO 2 .
  • the total amount of SiO 2 was the sum of the amount calculated from the weight loss and the amount of SiO 2 in the filtrate.
  • Table 2 shows quantitative values of the chemical composition of the silicic acid-boric acid compound particles obtained in Examples 1 to 10.
  • the composition of the melt is Li 2 O, Na 2 O, FeO, MnO, CoO, NiO, SiO 2 , P 2 O 5 and B 2 O 3 equivalent (unit: mol%), respectively, and the ratios shown in Table 3 Lithium carbonate (Li 2 CO 3 ), sodium carbonate (Na 2 CO 3 ), triiron tetroxide (Fe 3 O 4 ), manganese dioxide (MnO 2 ), tricobalt tetroxide (Co 3 O 4 ) , Nickel oxide (NiO), silicon dioxide (SiO 2 ), ammonium dihydrogen phosphate (NH 4 H 2 PO 4 ), and boron oxide (B 2 O 3 ) are weighed, mixed and pulverized in a dry process, A formulation was obtained.
  • Example 2 In the same manner as in Example 1, a melt was obtained using each raw material formulation, and a flaky solidified product was obtained through a cooling step.
  • the composition formula of the obtained melt is shown in the right column of Table 3.
  • the flake solidified product obtained in the cooling step was lightly kneaded and finely ground, and then coarsely pulverized using a pestle and mortar. Further, the coarsely pulverized solidified product was pulverized in a dry manner using a planetary mill using zirconia balls as a pulverizing medium to obtain a pulverized product.
  • the particle diameter of the pulverized product of Example 20 was measured using a laser diffraction / scattering particle size analyzer (manufactured by Horiba, Ltd., apparatus name: LA-950), the median diameter in terms of volume was 1.8 ⁇ m. .
  • the pulverized product obtained in the pulverization step was placed in a 3% by volume H 2 —Ar atmosphere, and each example was heated for 8 hours at four temperature conditions of 600 ° C., 700 ° C., 800 ° C., and 900 ° C., The mixture was cooled (air cooled) at a rate of ⁇ 200 ° C./hour to precipitate silicic acid-boric acid-phosphoric acid compound particles.
  • X-ray diffraction, particle size distribution, and composition analysis were performed on particles obtained by carrying out the heating step at 700 ° C.
  • the silicic acid-boric acid-phosphoric acid compound particles were crystals and a part of Si of the A 2 MSiO 4 crystal was a solid solution crystal in which P and B were substituted. Further, the particles obtained in Examples 22 to 25 exhibited diffraction patterns considered to be eutectics containing Li 2 MSiO 4 , LiMBO 3 , LiMPO 4 and their solid solutions. From the results, it was confirmed that when x and y were 0.2 ⁇ x + y ⁇ 0.7, a eutectic containing Li 2 MSiO 4 , LiMBO 3 , LiMPO 4 and a solid solution thereof was obtained.
  • the X-ray diffraction patterns of the crystals obtained in Examples 18, 19, 20, and 21 are shown in FIGS. 4 (a), (b), (c), and (d), respectively, in Examples 22, 23, and 24.
  • the X-ray diffraction patterns of the crystals obtained in, and 25 are shown in FIGS. 5 (a), (b), (c), and (d) for the crystals obtained in Examples 30, 31, and 33, respectively.
  • X-ray diffraction patterns are shown in FIGS. 6 (a), 6 (b) and 6 (c), respectively.
  • the particle size distribution of the silicic acid-boric acid-phosphoric acid compound obtained in Example 19 was measured with a laser diffraction / scattering particle size distribution analyzer (manufactured by Horiba, Ltd., apparatus name: LA-920). The median diameter in terms of volume was 2.5 ⁇ m. Furthermore, when the specific surface area of the silicic acid-boric acid-phosphoric acid compound was measured with a specific surface area measuring device (manufactured by Shimadzu Corporation, device name: ASAP2020), it was 1.4 m 2 / g.
  • composition analysis The chemical composition of the resulting silicic acid-boric acid-phosphoric acid compound particles was measured. First, silicic acid-boric acid-phosphoric acid compound particles were decomposed by heating and sealing with a 2.5 mol / L KOH solution at 120 ° C., and the decomposition solution was dried under hydrochloric acid acidity and filtered again as hydrochloric acid acidic solution. The filtrate and residue were obtained.
  • the amounts of Si, B, P, Fe, Mn, Co, and Ni in the filtrate are quantified using an inductively coupled emission spectroscopic analyzer (manufactured by Seiko Instruments Inc., apparatus name: SPS3100), and Li, Na was quantified using an atomic absorption photometer (manufactured by Hitachi High-Technologies Corporation, apparatus name: Z-2310). From the quantitative values of Si, B, P, Fe, Mn, Co, Ni, Li, and Na, SiO 2 , B 2 O 3 , P 2 O 5 , FeO, MnO, CoO, NiO, Li 2 O, and Na The amount of 2 O was calculated respectively.
  • the residue was ashed and then decomposed with hydrofluoric acid-sulfuric acid, and the weight loss due to this treatment was defined as the amount of SiO 2 .
  • the total amount of SiO 2 was the sum of the amount calculated from the weight loss and the amount of SiO 2 in the filtrate.
  • Table 4 shows quantitative values of the chemical composition of the silicic acid-boric acid-phosphoric acid compound particles obtained in Examples 18 to 25.
  • Example 36 to 47 The mass ratio of the coarsely pulverized product obtained by melting, cooling and coarsely pulverizing in Examples 1 to 4 and 18 to 25 and carbon black to the mass of carbon in the pulverized product and carbon black was 9: 1.
  • the carbon-containing pulverized product in each example was heated in Ar gas at two temperatures of 600 ° C. or 700 ° C. for 8 hours and cooled (air-cooled) at a rate of ⁇ 200 ° C./hour to obtain silicate compound particles. Obtained.
  • the X-ray diffraction pattern of the particles was consistent with that of olivine-type lithium iron silicate.
  • Example 36 an X-ray diffraction pattern of the obtained silicic acid-boric acid compound was obtained by heating at 700 ° C. for 8 hours and cooling (air cooling) at a rate of ⁇ 200 ° C./hour. These are shown in (a), (b), (c), and (d) of FIG.
  • Example 37 heating was performed at 700 ° C. for 8 hours, and cooling (air cooling) was performed at a rate of ⁇ 200 ° C./hour, and the carbon content of the obtained silicic acid-boric acid compound was measured using a carbon analyzer (Horiba, Ltd.). Manufactured, device name: EMIA-920V), it was 9.8% by mass.
  • Example 48 and 49 The coarsely pulverized product obtained by melting, quenching, and coarsely pulverizing in Examples 3 and 19, the carbon black and the sucrose aqueous solution were mixed in a mass ratio of the pulverized product, the carbon amount in the carbon black, and the carbon in the sucrose. 0.90: 0.05: 0.05, and pulverized and heated in the same manner as in Example 36 to obtain silicate compound particles.
  • the X-ray diffraction pattern of the particles coincided with that of olivine type lithium iron silicate as in Examples 3 and 19, respectively. In Examples 48 and 49, heating was performed at 700 ° C.
  • the composition of the melt is 23.7%, 52.6%, 21.1%, and 2.6% in terms of Li 2 O, FeO, SiO 2 , and B 2 O 3 (unit: mol%).
  • Lithium carbonate (Li 2 CO 3 ), triiron tetroxide (Fe 3 O 4 ), silicon dioxide (SiO 2 ), and boron oxide (B 2 O 3 ) were weighed, mixed and pulverized in a dry manner.
  • a raw material formulation was obtained.
  • the raw material formulation was melted in the same manner as in Example 1, but could not be melted.
  • the composition of the melt was 26.2%, 47.6%, 4.8%, and 21.4% in terms of Li 2 O, FeO, SiO 2 , and B 2 O 3 (unit: mol%).
  • Lithium carbonate (Li 2 CO 3 ), triiron tetroxide (Fe 3 O 4 ), silicon dioxide (SiO 2 ), and boron oxide (B 2 O 3 ) were weighed, mixed and pulverized in a dry manner.
  • a raw material formulation was obtained.
  • the raw material formulation was melted in the same manner as in Example 1, but could not be melted.
  • the composition of the melt is 26.2%, 47.6%, 4.8%, 14 in terms of Li 2 O, FeO, SiO 2 , B 2 O 3 , and P 2 O 5 (unit: mol%).
  • Lithium carbonate (Li 2 CO 3 ), triiron tetroxide (Fe 3 O 4 ), silicon dioxide (SiO 2 ), boron oxide (B 2 O 3 ), And ammonium dihydrogen phosphate (NH 4 H 2 PO 4 ) were weighed, mixed and pulverized in a dry manner to obtain a raw material formulation.
  • the raw material formulation was melted in the same manner as in Example 1, but could not be completely melted.
  • the composition of the melt is 32.8%, 34.5%, 31.0%, and 1.7% in terms of Li 2 O, FeO, SiO 2 , and B 2 O 3 (unit: mol%) Lithium carbonate (Li 2 CO 3 ), triiron tetroxide (Fe 3 O 4 ), silicon dioxide (SiO 2 ), and boron oxide (B 2 O 3 ) were weighed, mixed and pulverized in a dry manner. Thus, a raw material formulation was obtained. In the same manner as in Example 1, the raw material formulation was melted at 1,450 ° C. and then cooled at ⁇ 300 ° C./hour to obtain a crystallized product.
  • the mineral phase of the obtained crystallized product was identified using XRD, it was mainly composed of Li 2 SiO 3 and Fe 3 O 4 . That is, the target compound cannot be obtained unless the cooling step, the pulverizing step and the heating step are performed.
  • Examples 50 to 54 Production Examples of Positive Electrode for Li-ion Secondary Battery and Evaluation Battery
  • a pulverized product of silicate compound particles obtained by heating at 700 ° C. for 8 hours and cooling (air cooling) at a rate of ⁇ 200 ° C./hour, and 20 mass % Sucrose solution was mixed and pulverized so that the mass ratio of the pulverized product to the amount of carbon in the sucrose was 95: 5, heated in N 2 gas at 600 ° C. for 2 hours, and after cooling
  • the active material was obtained by grinding.
  • the active material, polyvinylidene fluoride resin (binder) and acetylene black (conductive material) are weighed so that the mass ratio is 85: 5: 10, and uniform in N-methylpyrrolidone (solvent)
  • the slurry was mixed until Next, the slurry was applied to an aluminum foil having a thickness of 30 ⁇ m with a bar coater. After drying this at 120 degreeC in the air and removing a solvent, after consolidating the coating layer with the roll press, it cut out to the strip shape of width 10mm * length 40mm.
  • the coating layer was peeled off leaving a 10 ⁇ 10 mm tip of strip-shaped aluminum foil, which was used as an electrode.
  • the coating thickness of the obtained electrode after roll pressing was 20 ⁇ m.
  • the obtained electrode was vacuum-dried at 150 ° C., then carried into a glove box filled with purified Ar gas, and opposed to a counter electrode in which a lithium foil was pressure-bonded to a nickel mesh with a porous polyethylene film separator. Both sides were fixed with a polyethylene plate.
  • the discharge capacities at the fifth cycle were 157 mAh / g (Example 50), 158 mAh / g (Example 51), 158 mAh / g (Example 52), 210 mAh / g (Example 53), and 171 mAh / g ( Example 54).
  • Examples 55 to 56 Using the silicic acid compound particles obtained in Examples 48 and 49 as an active material, a polyvinylidene fluoride resin as a binder and acetylene black as a conductive material in a mass ratio of 90: 5: 5 Except that, an electrode was produced in the same manner as in Example 50, and its charge / discharge characteristics were evaluated in the same manner as in Example 50.
  • the discharge capacities at the 10th cycle were 155 mAh / g (Example 55) and 168 mAh / g (Example 56), respectively.
  • Examples 1 to 49 a silicic acid-boric acid compound and a silicic acid-boric acid-phosphoric acid compound having a desired composition could be easily produced.
  • the produced silicic acid-boric acid compound and silicic acid-boric acid-phosphoric acid compound had excellent characteristics as a positive electrode material for a secondary battery and further as a secondary battery (Examples 50 to 56).
  • the method for producing a silicic acid compound of the present invention is useful because the composition of the silicic acid compound can be easily controlled and produced.
  • the obtained silicic acid compound is useful for a positive electrode material for a secondary battery and further for a secondary battery.
  • a secondary battery using the silicate compound of the present invention as a positive electrode material is useful as a secondary battery mounted in a plug-in hybrid vehicle or an electric vehicle, or as a storage battery for storing power.

Abstract

A method for manufacturing a silicate compound is provided, said method providing increased control over composition and particle size. After a solidified material is obtained by cooling a molten material represented by A2− d + a M b Si1− d D d O4− d + c1 (wherein A represents at least one element selected from the group consisting of lithium, sodium, and potassium; M represents at least one element selected from the group consisting of iron, manganese, cobalt, and nickel; D represents either boron or both boron and phosphorus; a satisfies −0.1 ≤ a ≤ 0.4; b satisfies 0.7 ≤ b ≤ 1.3; d satisfies 0 < d ≤ 0.7; and c1 is a number that depends on a, b, and the valence (N) of M and becomes c2 after a heating step), a pulverized material is obtained by pulverizing said solidified material. A silicate compound having a composition represented by A2− d + a M b Si1− d D d O4− d + c2 (wherein A, M, D, a, b, and d have the same meanings as above, and c2 is a number that depends on a, b, and the valence (N) of M) is manufactured by heating the pulverized material.

Description

ケイ酸化合物、二次電池用正極、二次電池、およびそれらの製造方法Silicic acid compound, positive electrode for secondary battery, secondary battery, and production method thereof
　本発明は、ケイ酸化合物、二次電池用正極、二次電池、およびそれらの製造方法に関する。 The present invention relates to a silicate compound, a positive electrode for a secondary battery, a secondary battery, and a method for producing them.
　近年、世界的なＣＯ２排出規制や省エネルギーの観点から、プラグインハイブリッド自動車や電気自動車の開発が進められている。また、スマートシティやスマートコミュニティの構想の実現のために、電力貯蔵用の蓄電池の開発が望まれている。これらの実現には、使用される二次電池が、安全性を維持しつつ、高容量化、高エネルギー化、大型化することが課題とされている。そして、次世代のリチウムイオン二次電池の正極材料等として、資源面、安全面、コスト面、安定性等の点での優位性から、オリビン型の正極材料が注目されている。 In recent years, plug-in hybrid vehicles and electric vehicles have been developed from the viewpoint of global CO 2 emission regulations and energy saving. In addition, in order to realize the concept of a smart city and a smart community, development of a storage battery for power storage is desired. In order to realize these, it is a problem that the secondary battery to be used is increased in capacity, energy, and size while maintaining safety. As the positive electrode material for the next generation lithium ion secondary battery, an olivine type positive electrode material has attracted attention because of advantages in terms of resources, safety, cost, stability, and the like.
　二次電池の正極の候補材料として、単位式中に２個のＬｉを含み、多電子反応による高容量化が可能なオリビン型ケイ酸化合物（Ｌｉ２ＦｅＳｉＯ４）が提案されている（非特許文献１参照）。 As a candidate material for a positive electrode of a secondary battery, an olivine-type silicic acid compound (Li 2 FeSiO 4 ) containing two Li in a unit formula and capable of increasing the capacity by a multi-electron reaction has been proposed (non-patent) Reference 1).
　特許文献１には、単位式中にｋ個のＬｉを含み、かつ[ＳｉＯ４]、[ＳＯ４]、[ＰＯ４]、[ＧｅＯ４]、[ＶＯ４]、[ＡｌＯ４]、[ＢＯ４]などを含む広い一般式の化合物であってオルトシリケート構造を有する化合物が電極材料として提案されている。 Patent Document 1 includes k Li in the unit formula, and [SiO 4 ], [SO 4 ], [PO 4 ], [GeO 4 ], [VO 4 ], [AlO 4 ], [BO]. 4 ] and the like, and compounds having an orthosilicate structure, which have a wide general formula, have been proposed as electrode materials.
特開２００１－２６６８８２号公報JP 2001-266882 A
　非特許文献１に記載されたＬｉ２ＦｅＳｉＯ４は、固相反応により製造されるため、製造工程が複雑で、製造コストがかさむ。 Since Li 2 FeSiO 4 described in Non-Patent Document 1 is manufactured by a solid-phase reaction, the manufacturing process is complicated and the manufacturing cost increases.
　特許文献１に電極材料として、Ｓｉを含む化合物として実際に開示されているのはＬｉ１．７Ｍｎ０．７Ｆｅ０．３Ｓｉ０．７Ｐ０．３Ｏ４であり、該化合物は、Ｌｉ２ＭｎＳｉＯ４およびＬｉＦｅＰＯ４を混合・粉砕し、管に封入し、加熱して製造する固相反応で製造している。固相反応は製造工程が複雑で、製造コストがかさみ、大量生産することが困難であり、組成制御も容易でない。 It is Li 1.7 Mn 0.7 Fe 0.3 Si 0.7 P 0.3 O 4 that is actually disclosed as an electrode material in Patent Document 1 as a compound containing Si. Li 2 MnSiO 4 and LiFePO 4 are mixed and pulverized, sealed in a tube, and heated to produce the solid phase reaction. The solid-phase reaction has a complicated manufacturing process, is expensive to manufacture, is difficult to mass-produce, and composition control is not easy.
　本発明の目的は、単位質量当たりの高容量化が可能なケイ酸化合物、より具体的にはケイ酸－ホウ酸化合物およびケイ酸－ホウ酸－リン酸化合物の、組成および粒径の制御がしやすい製造方法の提供にある。該化合物は、二次電池用正極および二次電池の正極に用いる活物質として有用である。本発明は、特性や信頼性に優れる二次電池用正極および二次電池を製造する方法をも提供する。 The object of the present invention is to control the composition and particle size of silicic acid compounds capable of increasing the capacity per unit mass, more specifically silicic acid-boric acid compounds and silicic acid-boric acid-phosphoric acid compounds. It is in providing a manufacturing method that is easy to do. The compound is useful as an active material used for a positive electrode for a secondary battery and a positive electrode for a secondary battery. The present invention also provides a positive electrode for a secondary battery having excellent characteristics and reliability and a method for producing the secondary battery.
　本発明は、以下の［１］～［１６］の発明である。
［１］下式（Ａ）で表される組成を有する溶融物を得る溶融工程、
　前記溶融物を冷却し固化物を得る冷却工程、
　前記固化物を粉砕し粉砕物を得る粉砕工程、および
　前記粉砕物を加熱して下式（Ｂ）で表される組成を有するケイ酸化合物を得る加熱工程、
をこの順に具備することを特徴とするケイ酸化合物の製造方法。
　Ａ２－ｄ＋ａＭｂＳｉ１－ｄＤｄＯ４－ｄ＋ｃ１　　　　　（Ａ）
（式中、元素ＡはＬｉ、ＮａおよびＫからなる群より選ばれる少なくとも１種の元素であり、元素ＭはＦｅ、Ｍｎ、ＣｏおよびＮｉからなる群より選ばれる少なくとも１種の元素であり、Ｄは、Ｂ、または、ＢおよびＰであり、ａは－０．１≦ａ≦０．４であり、ｂは０．７≦ｂ≦１．３であり、ｄは０＜ｄ≦０．７であり、ｃ１はａ、ｂ、およびＭの価数Ｎに依存する数であり、加熱工程後にｃ２となる数である。）ｄは０＜ｄ＜０．７であってもよい。
　　Ａ２－ｄ＋ａＭｂＳｉ１－ｄＤｄＯ４－ｄ＋ｃ２　　　　（Ｂ）
（式中、Ａ、Ｍ、Ｄ、ａ、ｂ、およびｄは前記と同じ意味を示すが、前記とは独立した値であり、ｃ２はａ、ｂ、およびＭの価数Ｎに依存する数である。）
［２］前記式（Ａ）で表される組成を有する溶融物が、下式（１）で表される組成を有する溶融物であり、前記式（Ｂ）で表される組成を有するケイ酸化合物が、下式（２）で表される組成を有するケイ酸－ホウ酸化合物である、［１］のケイ酸化合物の製造方法。
　Ａ２－ｘ＋ａＭｂＳｉ１－ｘＢｘＯ４－ｘ＋ｃ１１　　　　（１）
　Ａ２－ｘ＋ａＭｂＳｉ１－ｘＢｘＯ４－ｘ＋ｃ１２　　　　（２）
（式中、Ａ、Ｍ、ａ、およびｂは、それぞれ前記と同じ意味を示し、ｘは０＜ｘ≦０．７であり、ｃ１１はａ、ｂ、およびＭの価数Ｎに依存する数であり、加熱工程後にｃ１２となる数であり、ｃ１２はａ、ｂ、およびＭの価数Ｎに依存する数である。ただし、式（１）と式（２）において、ａ、ｂ、およびｘは独立した値を示す。）
［３］前記溶融工程が、
　元素Ａを含む化合物が、Ａの炭酸塩、Ａの炭酸水素塩、Ａの水酸化物、Ａのケイ酸塩、Ａのリン酸塩、Ａのリン酸水素塩、Ａのホウ酸塩、Ａの硝酸塩、Ａの塩化物、Ａの硫酸塩、Ａの酢酸塩およびＡのシュウ酸塩からなる群より選ばれる少なくとも１種（ただし、該１種以上の一部または全部は、それぞれ、水和塩を形成していてもよい。）として含まれ、
　元素Ｍを含む化合物が、Ｍの酸化物、Ｍのオキシ水酸化物、Ｍのケイ酸塩、Ｍのホウ酸塩、Ｍの金属、Ｍのリン酸塩、Ｍの塩化物、Ｍの硝酸塩、Ｍの硫酸塩およびＭの有機塩からなる群より選ばれる少なくとも１種として含まれ、
　Ｓｉを含む化合物が、酸化ケイ素、Ａのケイ酸塩、Ｍのケイ酸塩およびケイ素のアルコキシドからなる群より選ばれる少なくとも１種として含まれ、
　Ｂを含む化合物が、酸化ホウ素、ホウ酸、Ａのホウ酸塩およびＭのホウ酸塩からなる群より選ばれる少なくとも１種として含まれる、
原料調合物を加熱して、前記式（１）で表される組成を有する溶融物を得る工程である、［２］のケイ酸化合物の製造方法。
［４］前記式（Ａ）で表される組成を有する溶融物が、下式（３）で表される組成を有する溶融物であり、前記式（Ｂ）で表される組成を有するケイ酸化合物が、下式（４）で表される組成を有するケイ酸－ホウ酸－リン酸化合物である、［１］のケイ酸化合物の製造方法。
　Ａ２－ｘ－ｙ＋ａＭｂＳｉ１－（ｘ＋ｙ）ＢｘＰｙＯ４－ｘ＋ｃ２１　　　　　（３）
　Ａ２－ｘ－ｙ＋ａＭｂＳｉ１－（ｘ＋ｙ）ＢｘＰｙＯ４－ｘ＋ｃ２２　　　　　（４）
（式中、Ａ、Ｍ、ａ、およびｂは、それぞれ前記と同じ意味を示し、ｘは０＜ｘ≦０．７であり、ｙは０＜ｙ≦０．７であり、０＜（ｘ＋ｙ）≦０．７を満たし、ｃ２１はａ、ｂ、およびＭの価数Ｎに依存する数であり、加熱工程後にｃ２２となる数であり、ｃ２２はａ、ｂ、およびＭの価数Ｎに依存する数である。ただし、式（３）と式（４）において、ａ、ｂ、ｘ、およびｙは独立した値を示す。）
［５］前記溶融工程が、
　元素Ａを含む化合物が、Ａの炭酸塩、Ａの炭酸水素塩、Ａの水酸化物、Ａのケイ酸塩、Ａのリン酸塩、Ａのリン酸水素塩、Ａのホウ酸塩、Ａの硝酸塩、Ａの塩化物、Ａの硫酸塩、Ａの酢酸塩およびＡのシュウ酸塩からなる群より選ばれる少なくとも１種（ただし、該１種以上の一部または全部は、それぞれ、水和塩を形成していてもよい。）として含まれ、
　元素Ｍを含む化合物が、Ｍの酸化物、Ｍのオキシ水酸化物、Ｍのケイ酸塩、Ｍのホウ酸塩、Ｍの金属、Ｍのリン酸塩、Ｍの塩化物、Ｍの硝酸塩、Ｍの硫酸塩およびＭの有機塩からなる群より選ばれる少なくとも１種として含まれ、
　Ｓｉを含む化合物が、酸化ケイ素、Ａのケイ酸塩、Ｍのケイ酸塩およびケイ素のアルコキシドからなる群より選ばれる少なくとも１種として含まれ、
　Ｂを含む化合物が、酸化ホウ素、ホウ酸、Ａのホウ酸塩、Ｍのホウ酸塩およびリン酸ホウ素からなる群より選ばれる少なくとも１種として含まれ、
　Ｐを含む化合物が、酸化リン、リン酸アンモニウム、リン酸水素アンモニウム、リン酸ホウ素、リン酸、ポリリン酸、亜リン酸、次亜リン酸、Ａのリン酸塩およびＭのリン酸塩からなる群より選ばれる少なくとも１種として含まれる、
原料調合物を加熱して、前記式（３）で表される組成を有する溶融物を得る工程である、［４］のケイ酸化合物の製造方法。
［６］前記元素ＡがＬｉである、［１］～［５］のケイ酸化合物の製造方法。
［７］前記元素ＭがＦｅおよびＭｎからなる群より選ばれる少なくとも１種である、［１］～［６］のケイ酸化合物の製造方法。
［８］前記式（１）で表される組成を有する溶融物が、下式（５Ａ）で表される組成を有する溶融物であり、前記式（２）で表される組成を有するケイ酸－ホウ酸化合物が、下式（５）で表される組成を有するオリビン型結晶粒子を含む化合物である、［２］のケイ酸化合物の製造方法。
　Ｌｉ２－ｘ＋ａ（ＦｅｍＭｎ１－ｍ）ｂＳｉ１－ｘＢｘＯ４－ｘ＋ｃ１１　（５Ａ）
　Ｌｉ２－ｘ＋ａ（ＦｅｍＭｎ１－ｍ）ｂＳｉ１－ｘＢｘＯ４－ｘ＋ｃ１２　（５）
（式中、ａ、ｂ、ｃ１１、ｃ１２、およびｘは前記と同じ意味を示し、ｍは０≦ｍ≦１である。ただし、式（５Ａ）と式（５）において、ａ、ｂ、ｘ、およびｍは独立した値を示す。）
［９］前記式（３）で表される組成を有する溶融物が、下式（６Ａ）で表される組成を有する溶融物であり、前記式（４）で表される組成を有するケイ酸－ホウ酸－リン酸化合物が、下式（６）で表される組成を有するオリビン型結晶粒子を含む化合物である、［４］のケイ酸化合物の製造方法。
　Ｌｉ２－ｘ－ｙ＋ａ（ＦｅｍＭｎ１－ｍ）ｂＳｉ１－（ｘ＋ｙ）ＢｘＰｙＯ４－ｘ＋ｃ２１　　（６Ａ）
　Ｌｉ２－ｘ－ｙ＋ａ（ＦｅｍＭｎ１－ｍ）ｂＳｉ１－（ｘ＋ｙ）ＢｘＰｙＯ４－ｘ＋ｃ２２　（６）
（式中、ａ、ｂ、ｃ２１、ｃ２２、ｘ、およびｙは前記と同じ意味を示し、ｍは０≦ｍ≦１である。ただし、式（６Ａ）と式（６）において、ａ、ｂ、ｘ、ｙ、およびｍは独立した値を示す。）
［１０］前記冷却工程において、冷却速度を－１０３℃／秒～－１０１０℃／秒とする、［１］～［９］のケイ酸化合物の製造方法。
［１１］前記粉砕工程において、前記固化物に、有機化合物および炭素粉末からなる群より選択される少なくとも１種の炭素源を含ませ、かつ該炭素源中の炭素換算量（質量）の割合が、固化物の質量と、該炭素源中の炭素換算量（質量）との合計質量に対して０．１～２０質量％である、［１］～［１０］のケイ酸化合物の製造方法。
［１２］前記加熱工程を５００～１，０００℃に加熱することにより行う、［１］～［１１］のケイ酸化合物の製造方法。 The present invention is the following [1] to [16].
[1] A melting step for obtaining a melt having a composition represented by the following formula (A):
A cooling step of cooling the melt to obtain a solidified product,
A pulverization step of pulverizing the solidified product to obtain a pulverized product, and a heating step of heating the pulverized product to obtain a silicate compound having a composition represented by the following formula (B):
In this order. A method for producing a silicic acid compound.
A 2-d + a M b Si 1-d D d O 4-d + c1 (A)
(In the formula, element A is at least one element selected from the group consisting of Li, Na and K, and element M is at least one element selected from the group consisting of Fe, Mn, Co and Ni, D is B, or B and P, a is −0.1 ≦ a ≦ 0.4, b is 0.7 ≦ b ≦ 1.3, and d is 0 <d ≦ 0. 7 and c1 is a number that depends on the valence N of a, b, and M, and is a number that becomes c2 after the heating step.) D may be 0 <d <0.7.
A 2-d + a M b Si 1-d D d O 4-d + c2 (B)
(In the formula, A, M, D, a, b, and d have the same meanings as described above, but are independent values, and c2 is a number that depends on the valence N of a, b, and M. .)
[2] The melt having the composition represented by the formula (A) is a melt having the composition represented by the following formula (1), and the silicic acid having the composition represented by the formula (B) The method for producing a silicic acid compound according to [1], wherein the compound is a silicic acid-boric acid compound having a composition represented by the following formula (2).
A 2-x + a M b Si 1-x B x O 4-x + c11 (1)
A 2-x + a M b Si 1-x B x O 4-x + c12 (2)
(In the formula, A, M, a, and b each have the same meaning as described above, x is 0 <x ≦ 0.7, and c11 is a number that depends on the valence N of a, b, and M. And c12 is a number that depends on the valence N of a, b, and M. In Formula (1) and Formula (2), a, b, and x represents an independent value.)
[3] The melting step includes
The compound containing element A is A carbonate, A bicarbonate, A hydroxide, A silicate, A phosphate, A hydrogen phosphate, A borate, A Nitrate, A chloride, A sulfate, A acetate, and A oxalate, wherein at least one or all of the one or more are hydrated. A salt may be formed.)
The compound containing element M is M oxide, M oxyhydroxide, M silicate, M borate, M metal, M phosphate, M chloride, M nitrate, Included as at least one selected from the group consisting of M sulfate and M organic salt;
A compound containing Si is included as at least one selected from the group consisting of silicon oxide, A silicate, M silicate, and silicon alkoxide,
The compound containing B is included as at least one selected from the group consisting of boron oxide, boric acid, A borate and M borate.
The method for producing a silicic acid compound according to [2], which is a step of heating a raw material formulation to obtain a melt having a composition represented by the formula (1).
[4] The melt having the composition represented by the formula (A) is a melt having the composition represented by the following formula (3), and the silicic acid having the composition represented by the formula (B) The method for producing a silicic acid compound according to [1], wherein the compound is a silicic acid-boric acid-phosphoric acid compound having a composition represented by the following formula (4):
A 2-x-y + a M b Si 1- (x + y) B x P y O 4-x + c21 (3)
A 2-x-y + a M b Si 1- (x + y) B x P y O 4-x + c22 (4)
(Wherein A, M, a, and b each have the same meaning as described above, x is 0 <x ≦ 0.7, y is 0 <y ≦ 0.7, and 0 <(x + y ) ≦ 0.7, c21 is a number that depends on the valence N of a, b, and M, and is a number that becomes c22 after the heating step, and c22 is the valence N of a, b, and M. (In formulas (3) and (4), a, b, x, and y represent independent values.)
[5] The melting step includes
The compound containing element A is A carbonate, A bicarbonate, A hydroxide, A silicate, A phosphate, A hydrogen phosphate, A borate, A Nitrate, A chloride, A sulfate, A acetate, and A oxalate, wherein at least one or all of the one or more are hydrated. A salt may be formed.)
The compound containing element M is M oxide, M oxyhydroxide, M silicate, M borate, M metal, M phosphate, M chloride, M nitrate, Included as at least one selected from the group consisting of M sulfate and M organic salt;
A compound containing Si is included as at least one selected from the group consisting of silicon oxide, A silicate, M silicate, and silicon alkoxide,
A compound containing B is included as at least one selected from the group consisting of boron oxide, boric acid, A borate, M borate and boron phosphate;
The compound containing P consists of phosphorus oxide, ammonium phosphate, ammonium hydrogen phosphate, boron phosphate, phosphoric acid, polyphosphoric acid, phosphorous acid, hypophosphorous acid, A phosphate and M phosphate Included as at least one selected from the group,
[4] The method for producing a silicic acid compound according to [4], wherein the raw material preparation is heated to obtain a melt having a composition represented by the formula (3).
[6] The method for producing a silicate compound according to [1] to [5], wherein the element A is Li.
[7] The method for producing a silicate compound according to any one of [1] to [6], wherein the element M is at least one selected from the group consisting of Fe and Mn.
[8] The melt having the composition represented by the formula (1) is a melt having the composition represented by the following formula (5A), and the silicic acid having the composition represented by the formula (2) The method for producing a silicic acid compound according to [2], wherein the boric acid compound is a compound containing olivine type crystal particles having a composition represented by the following formula (5).
Li 2-x + a (Fe m Mn 1-m) b Si 1-x B x O 4-x + c11 (5A)
Li 2-x + a (Fe m Mn 1-m ) b Si 1-x B x O 4-x + c12 (5)
(Wherein a, b, c11, c12, and x have the same meaning as described above, and m is 0 ≦ m ≦ 1, provided that in formulas (5A) and (5), a, b, x , And m are independent values.)
[9] The melt having the composition represented by the formula (3) is a melt having the composition represented by the following formula (6A), and the silicic acid having the composition represented by the formula (4) The method for producing a silicic acid compound according to [4], wherein the boric acid-phosphoric acid compound is a compound containing olivine type crystal particles having a composition represented by the following formula (6).
Li 2-x-y + a (Fe m Mn 1-m) b Si 1- (x + y) B x P y O 4-x + c21 (6A)
Li 2-x-y + a (Fe m Mn 1-m) b Si 1- (x + y) B x P y O 4-x + c22 (6)
(Wherein, a, b, c21, c22, x, and y have the same meanings as described above, and m is 0 ≦ m ≦ 1, provided that in formulas (6A) and (6), a, b , X, y, and m are independent values.)
[10] The method for producing a silicic acid compound according to [1] to [9], wherein, in the cooling step, the cooling rate is −10 3 ° C./second to −10 10 ° C./second.
[11] In the pulverization step, the solidified product includes at least one carbon source selected from the group consisting of an organic compound and carbon powder, and a ratio of a carbon conversion amount (mass) in the carbon source is The method for producing a silicic acid compound according to [1] to [10], wherein the mass is 0.1 to 20% by mass relative to the total mass of the mass of the solidified product and the carbon conversion amount (mass) in the carbon source.
[12] The method for producing a silicate compound according to [1] to [11], wherein the heating step is performed by heating to 500 to 1,000 ° C.
［１３］［１］～［１２］の製造方法によってケイ酸化合物を得て、次に該ケイ酸化合物を二次電池用正極材料に用いて二次電池用正極を製造することを特徴とする二次電池用正極の製造方法。
［１４］［１３］の製造方法で二次電池用正極を得て、次に、該二次電池用正極を用いて二次電池を製造することを特徴とする二次電池の製造方法。
［１５］下式（２）で表される組成を有することを特徴とするケイ酸－ホウ酸化合物。
　Ａ２－ｘ＋ａＭｂＳｉ１－ｘＢｘＯ４－ｘ＋ｃ１２　　　　（２）
（式中、元素ＡはＬｉ、ＮａおよびＫからなる群より選ばれる少なくとも１種の元素であり、元素ＭはＦｅ、Ｍｎ、ＣｏおよびＮｉからなる群より選ばれる少なくとも１種の元素であり、ａは－０．１≦ａ≦０．４であり、ｂは０．７≦ｂ≦１．３であり、ｘは０＜ｘ≦０．７であり、ｃ１２はａ、ｂ、およびＭの価数Ｎに依存する数である。）
［１６］下式（４）で表される組成を有することを特徴とするケイ酸－ホウ酸－リン酸化合物。
　Ａ２－ｘ－ｙ＋ａＭｂＳｉ１－（ｘ＋ｙ）ＢｘＰｙＯ４－ｘ＋ｃ２２　　　　　（４）
（式中、元素ＡはＬｉ、ＮａおよびＫからなる群より選ばれる少なくとも１種の元素であり、元素ＭはＦｅ、Ｍｎ、ＣｏおよびＮｉからなる群より選ばれる少なくとも１種の元素であり、ａは－０．１≦ａ≦０．４であり、ｂは０．７≦ｂ≦１．３であり、ｘは０＜ｘ≦０．７であり、ｙは０＜ｙ≦０．７であり、０＜（ｘ＋ｙ）≦０．７を満たし、ｃ２２はａ、ｂ、およびＭの価数Ｎに依存する数である。） [13] A method for producing a positive electrode for a secondary battery by obtaining a silicate compound by the production method of [1] to [12] and then using the silicate compound as a positive electrode material for a secondary battery. A method for producing a positive electrode for a secondary battery.
[14] A method for producing a secondary battery, comprising obtaining a positive electrode for a secondary battery by the production method of [13], and then producing a secondary battery using the positive electrode for a secondary battery.
[15] A silicic acid-boric acid compound having a composition represented by the following formula (2):
A 2-x + a M b Si 1-x B x O 4-x + c12 (2)
(In the formula, element A is at least one element selected from the group consisting of Li, Na and K, and element M is at least one element selected from the group consisting of Fe, Mn, Co and Ni, a is −0.1 ≦ a ≦ 0.4, b is 0.7 ≦ b ≦ 1.3, x is 0 <x ≦ 0.7, and c12 is a, b, and M (The number depends on the valence N.)
[16] A silicic acid-boric acid-phosphoric acid compound having a composition represented by the following formula (4):
A 2-x-y + a M b Si 1- (x + y) B x P y O 4-x + c22 (4)
(In the formula, element A is at least one element selected from the group consisting of Li, Na and K, and element M is at least one element selected from the group consisting of Fe, Mn, Co and Ni, a is −0.1 ≦ a ≦ 0.4, b is 0.7 ≦ b ≦ 1.3, x is 0 <x ≦ 0.7, and y is 0 <y ≦ 0.7. And 0 <(x + y) ≦ 0.7, and c22 is a number depending on the valence N of a, b, and M.)
　本発明の製造方法は、ケイ酸化合物の組成、粒径およびこれらの均一性を制御しやすいため、電極材料として有用であり、種々の組成を有するケイ酸化合物を効率的に製造できる。本発明のケイ酸化合物は多電子型の反応を示す化合物である。よって、本発明のケイ酸化合物を用いることにより、特性や信頼性に優れる二次電池用正極材料、および二次電池が製造できる。さらに、本発明は、ケイ酸化合物を提供する。 The production method of the present invention is useful as an electrode material because it is easy to control the composition, particle size and uniformity of the silicate compound, and can efficiently produce silicate compounds having various compositions. The silicic acid compound of the present invention is a compound showing a multi-electron type reaction. Therefore, by using the silicate compound of the present invention, a positive electrode material for a secondary battery and a secondary battery that are excellent in characteristics and reliability can be manufactured. Furthermore, the present invention provides a silicate compound.
実施例１、２、３、および４で製造したケイ酸－ホウ酸化合物のＸ線回折パターンを示す図である。FIG. 3 is a diagram showing X-ray diffraction patterns of silicic acid-boric acid compounds produced in Examples 1, 2, 3, and 4. 実施例５、６、および７で製造したケイ酸－ホウ酸化合物のＸ線回折パターンを示す図である。FIG. 4 is a diagram showing an X-ray diffraction pattern of silicic acid-boric acid compounds produced in Examples 5, 6, and 7. 実施例８、９、および１０で製造したケイ酸－ホウ酸化合物のＸ線回折パターンを示す図である。FIG. 6 is a view showing an X-ray diffraction pattern of silicic acid-boric acid compounds produced in Examples 8, 9, and 10. 実施例１８、１９、２０、および２１で製造したケイ酸－ホウ酸－リン酸化合物のＸ線回折パターンを示す図である。FIG. 3 is a diagram showing an X-ray diffraction pattern of silicic acid-boric acid-phosphoric acid compounds produced in Examples 18, 19, 20, and 21. 実施例２２、２３、２４、および２５で製造したケイ酸－ホウ酸－リン酸化合物のＸ線回折パターンを示す図である。FIG. 3 is a diagram showing an X-ray diffraction pattern of silicic acid-boric acid-phosphoric acid compounds produced in Examples 22, 23, 24, and 25. 実施例３０、３１、および３３で製造したケイ酸－ホウ酸－リン酸化合物のＸ線回折パターンを示す図である。FIG. 3 is a diagram showing an X-ray diffraction pattern of silicic acid-boric acid-phosphoric acid compounds produced in Examples 30, 31, and 33. 実施例３６、３７、３８、および３９で製造したケイ酸－ホウ酸化合物のＸ線回折パターンを示す図である。FIG. 4 is a diagram showing an X-ray diffraction pattern of silicic acid-boric acid compounds produced in Examples 36, 37, 38, and 39.
＜ケイ酸化合物の製造方法＞
　本発明のケイ酸化合物の製造方法は、以下の溶融工程（Ｐ１）、冷却工程（Ｐ２）、粉砕工程（Ｐ３）、および加熱工程（Ｐ４）の各工程を、この順に行う。（Ｐ１）～（Ｐ４）の工程前、工程間、および工程後には、各工程に影響を及ぼさない限り、他の工程を行ってもよい。
溶融工程（Ｐ１）：式Ａ２－ｄ＋ａＭｂＳｉ１－ｄＤｄＯ４－ｄ＋ｃ１（式中の記号は前記と同じ意味を示す。）で表される組成を有する溶融物を得る工程、
冷却工程（Ｐ２）：前記溶融物を冷却し固化物を得る工程、
粉砕工程（Ｐ３）：前記固化物を粉砕し粉砕物を得る工程、および
加熱工程（Ｐ４）：前記粉砕物を加熱して、式Ａ２－ｄ＋ａＭｂＳｉ１－ｄＤｄＯ４－ｄ＋ｃ２（式中の記号は前記と同じ意味を示す。）で表される組成を有するケイ酸を得る工程。
　本発明のケイ酸化合物の製造方法は、具体的には、以下のケイ酸－ホウ酸化合物の製造方法、ケイ酸－ホウ酸－リン酸化合物の製造方法として表わされる。 <Method for producing silicic acid compound>
In the method for producing a silicate compound of the present invention, the following steps of the melting step (P1), the cooling step (P2), the pulverizing step (P3), and the heating step (P4) are performed in this order. Other steps may be performed before, between, and after the steps (P1) to (P4) as long as each step is not affected.
Melting step (P1): a step of obtaining a melt having a composition represented by the formula A 2-d + a M b Si 1-d D d O 4-d + c1 (wherein the symbols have the same meaning as described above),
Cooling step (P2): a step of cooling the melt to obtain a solidified product,
Crushing step (P3): crushing the solidified product to obtain a pulverized product, and heating step (P4): heating the pulverized product to obtain the formula A 2-d + a Mb Si 1-d D d O 4-d + c2 (The symbol in a formula shows the same meaning as the above.) The process of obtaining the silicic acid which has a composition represented.
The method for producing a silicic acid compound of the present invention is specifically represented as the following methods for producing a silicic acid-boric acid compound and methods for producing a silicic acid-boric acid-phosphoric acid compound.
　本発明のケイ酸－ホウ酸化合物の製造方法は、以下の溶融工程（Ｐ１１）、冷却工程（Ｐ１２）、粉砕工程（Ｐ１３）、および加熱工程（Ｐ１４）の各工程を、この順に行う。（Ｐ１１）～（Ｐ１４）の工程前、工程間、および工程後には、各工程に影響を及ぼさない限り、他の工程を行ってもよい。 In the method for producing a silicic acid-boric acid compound of the present invention, the following steps of the melting step (P11), the cooling step (P12), the pulverizing step (P13), and the heating step (P14) are performed in this order. Other steps may be performed before, between, and after the steps (P11) to (P14) as long as each step is not affected.
溶融工程（Ｐ１１）：式Ａ２－ｘ＋ａＭｂＳｉ１－ｘＢｘＯ４－ｘ＋ｃ１１（式中の記号は前記と同じ意味を示す。）で表される組成を有する溶融物を得る工程、
冷却工程（Ｐ１２）：前記溶融物を冷却し固化物を得る工程、
粉砕工程（Ｐ１３）：前記固化物を粉砕し粉砕物を得る工程、および
加熱工程（Ｐ１４）：前記粉砕物を加熱して、式Ａ２－ｘ＋ａＭｂＳｉ１－ｘＢｘＯ４－ｘ＋ｃ１２（式中の記号は前記と同じ意味を示す。）で表される組成を有するケイ酸－ホウ酸化合物を得る工程。 Melting step (P11): a step of obtaining a melt having a composition represented by the formula A 2-x + a M b Si 1-x B x O 4-x + c11 (wherein the symbols have the same meanings as described above),
Cooling step (P12): a step of cooling the melt to obtain a solidified product,
Milling step (P13): obtaining a ground product was pulverized said solidified product, and the heating step (P14): by heating the ground product of the formula A 2-x + a M b Si 1-x B x O 4-x + c12 A step of obtaining a silicic acid-boric acid compound having a composition represented by the formula:
　本発明のケイ酸－ホウ酸－リン酸化合物の製造方法は、以下の溶融工程（Ｐ２１）、冷却工程（Ｐ２２）、粉砕工程（Ｐ２３）、および加熱工程（Ｐ２４）の各工程を、この順に行う。（Ｐ２１）～（Ｐ２４）の工程前、工程間、および工程後には、各工程に影響を及ぼさない限り、他の工程を行ってもよい。 The method for producing a silicic acid-boric acid-phosphoric acid compound of the present invention comprises the following steps in this order: a melting step (P21), a cooling step (P22), a pulverizing step (P23), and a heating step (P24). Do. Other steps may be performed before, between, and after the steps (P21) to (P24) as long as each step is not affected.
　溶融工程（Ｐ２１）：式Ａ２－ｘ－ｙ＋ａＭｂＳｉ１－（ｘ＋ｙ）ＢｘＰｙＯ４－ｘ＋ｃ２１（式中の記号は前記と同じ意味を示す。）で表される組成を有する溶融物を得る工程、
冷却工程（Ｐ２２）：前記溶融物を冷却し固化物を得る工程、
粉砕工程（Ｐ２３）：前記固化物を粉砕し粉砕物を得る工程、および
加熱工程（Ｐ２４）：前記粉砕物を加熱して式Ａ２－ｘ－ｙ＋ａＭｂＳｉ１－（ｘ＋ｙ）ＢｘＰｙＯ４－ｘ＋ｃ２２（式中の記号は前記と同じ意味を示す。）で表される組成を有するケイ酸－ホウ酸－リン酸化合物を得る工程。
　以下、各工程について具体的に説明する。 Melting step (P21): wherein A 2-x-y + a M b Si 1- (x + y) B x P y O 4-x + c21 ( symbols in the formula are as defined above.) Having a composition represented by Obtaining a melt,
Cooling step (P22): a step of cooling the melt to obtain a solidified product,
Crushing step (P23): crushing the solidified product to obtain a pulverized product, and heating step (P24): heating the pulverized product to obtain a formula A 2-xy + a Mb Si 1- (x + y) B x P A step of obtaining a silicic acid-boric acid-phosphoric acid compound having a composition represented by y O 4-x + c22 (wherein the symbols have the same meaning as described above).
Hereinafter, each step will be specifically described.
［溶融工程（Ｐ１）、（Ｐ１１）、（Ｐ２１）］
　本発明のケイ酸－ホウ酸化合物の製造方法における溶融工程（Ｐ１１）は、下式（１）で表される溶融物を得る工程である。
　Ａ２－ｘ＋ａＭｂＳｉ１－ｘＢｘＯ４－ｘ＋ｃ１１　　　　　（１）
（式中の記号は前記と同じ意味を示す。） [Melting Steps (P1), (P11), (P21)]
The melting step (P11) in the method for producing a silicic acid-boric acid compound of the present invention is a step of obtaining a melt represented by the following formula (1).
A 2-x + a M b Si 1-x B x O 4-x + c11 (1)
(The symbols in the formula have the same meaning as described above.)
　溶融工程においては、元素源（元素Ａ、元素Ｍ、Ｓｉ、およびＢ）を含む原料を、式（１）で表される組成となるように調整してなる原料調合物をまず準備するのが好ましい。 In the melting step, a raw material formulation prepared by adjusting raw materials including element sources (element A, element M, Si, and B) to have a composition represented by formula (1) is prepared first. preferable.
　式（１）において、ａは－０．１≦ａ≦０．４、ｂは０．７≦ｂ≦１．３の範囲である。原料調合物におけるａおよびｂを該範囲にすることによって、目的とする組成を有するケイ酸－ホウ酸化合物を製造できる。加えて、原料調合物を良好に溶融でき、均一な溶融物が得られる。また、ｘを０＜ｘ≦０．７にすることによって、二次電池用正極材料として用いた場合に多電子型の反応（単位モル数当たり１ｍｏｌを超えるＡを引き抜く反応）を起こすケイ酸－ホウ酸化合物を製造することができ、二次電池の理論電気容量を高めることができる。ｘは０＜ｘ＜０．７であってもよい。 In the formula (1), a is in the range of −0.1 ≦ a ≦ 0.4 and b is in the range of 0.7 ≦ b ≦ 1.3. A silicic acid-boric acid compound having a target composition can be produced by setting a and b in the raw material formulation within the above ranges. In addition, the raw material formulation can be melted well, and a uniform melt can be obtained. In addition, by setting x to 0 <x ≦ 0.7, silicic acid that causes a multi-electron type reaction (reaction that pulls out more than 1 mol per unit mole) when used as a positive electrode material for a secondary battery A boric acid compound can be produced and the theoretical electric capacity of the secondary battery can be increased. x may be 0 <x <0.7.
　式（１）中、ａおよびｂは、多電子型の反応をより容易に起こさせうることから－０．１≦ａ≦０．３、０．８≦ｂ≦１．３にすることがより好ましい。また、０≦ａ≦０．３、１．０≦ｂ≦１．３にすると、充放電によるケイ酸－ホウ酸化合物の構造変化が生じない範囲内で、理論電気容量を高める効果が大きい利点がある。 In formula (1), a and b can cause a multi-electron type reaction more easily, so that −0.1 ≦ a ≦ 0.3 and 0.8 ≦ b ≦ 1.3 are more preferable. preferable. In addition, when 0 ≦ a ≦ 0.3 and 1.0 ≦ b ≦ 1.3, there is a great effect of increasing the theoretical electric capacity within a range in which the structural change of the silicic acid-boric acid compound due to charge / discharge does not occur. There is.
　式（１）中、ｃ１１の値は、ａ、ｂ、およびＭの価数Ｎに依存する数である。組成式中の元素の価数は、後の粉砕工程および／または加熱工程で変化しうることから、加熱工程後にｃ１２となる値にｃ１１を調節する。例えば、加熱工程で成分の酸化還元、揮発等によりｃ１１の値が増減する場合には、該増減を考慮に入れた値とするのが好ましい。本発明の製造方法においては、ｃ１１を目的物のｃ１２に対して０．９～１．２倍値としておくのが好ましい。 In the formula (1), the value of c11 is a number that depends on the valence N of a, b, and M. Since the valence of the element in the composition formula can be changed in the subsequent pulverization step and / or heating step, c11 is adjusted to a value that becomes c12 after the heating step. For example, when the value of c11 increases / decreases due to oxidation / reduction or volatilization of components in the heating process, it is preferable to set the value taking into account the increase / decrease. In the production method of the present invention, c11 is preferably 0.9 to 1.2 times the value of c12 of the target product.
　式（１）の元素Ａは、Ｌｉ、ＮａおよびＫからなる群より選ばれる少なくとも１種の元素である。元素Ａは二次電池用正極材料として適しているため、Ｌｉを必須とするのが好ましく、Ｌｉのみであることが特に好ましい。Ｌｉを含むケイ酸－ホウ酸化合物は、二次電池の単位体積（質量）当たりの容量を高くする。 The element A in the formula (1) is at least one element selected from the group consisting of Li, Na, and K. Since the element A is suitable as a positive electrode material for a secondary battery, it is preferable to make Li essential, and it is particularly preferable to use only Li. The silicic acid-boric acid compound containing Li increases the capacity per unit volume (mass) of the secondary battery.
　式（１）の元素ＭはＦｅ、Ｍｎ、ＣｏおよびＮｉからなる群より選ばれる少なくとも１種の元素である。元素Ｍは１種のみ、または、２種からなるのが好ましい。特に本発明の製造方法で製造するケイ酸－ホウ酸化合物を二次電池用正極材料に使用する場合には、元素ＭはＦｅのみ、Ｍｎのみ、またはＦｅとＭｎとの２種からなるのが、コストの点で好ましい。元素Ｍの価数Ｎは本発明の製造方法の各工程で変化しうる数値であり、＋２～＋４の範囲である。該価数Ｎは、元素ＭがＦｅの場合は＋２、＋８／３または＋３、Ｍｎの場合は＋２、＋３または＋４、Ｃｏの場合は＋２、＋８／３または＋３、およびＮｉの場合は＋２または＋４が好ましい。また、該価数Ｎは、溶融工程が単純化するために、＋２であることがより好ましい。 The element M in the formula (1) is at least one element selected from the group consisting of Fe, Mn, Co, and Ni. The element M is preferably composed of only one kind or two kinds. In particular, when the silicic acid-boric acid compound produced by the production method of the present invention is used for a positive electrode material for a secondary battery, the element M consists of only Fe, Mn alone, or Fe and Mn. This is preferable in terms of cost. The valence N of the element M is a numerical value that can change in each step of the production method of the present invention, and is in the range of +2 to +4. The valence N is +2, +8/3 or +3 when the element M is Fe, +2, +3 or +4 when Mn, +2, +8/3 or +3 when Co and +2 or when Ni +4 is preferred. The valence N is more preferably +2 in order to simplify the melting process.
　本発明のケイ酸－ホウ酸－リン酸化合物の製造方法における溶融工程（Ｐ２１）は、下式（３）で表される溶融物を得る工程である。
　Ａ２－ｘ－ｙ＋ａＭｂＳｉ１－（ｘ＋ｙ）ＢｘＰｙＯ４－ｘ＋ｃ２１　　　　　（３）
（式中の記号は前記と同じ意味を示す。） The melting step (P21) in the method for producing a silicic acid-boric acid-phosphoric acid compound of the present invention is a step of obtaining a melt represented by the following formula (3).
A 2-x-y + a M b Si 1- (x + y) B x P y O 4-x + c21 (3)
(The symbols in the formula have the same meaning as described above.)
　溶融工程においては、元素源（元素Ａ、元素Ｍ、Ｓｉ、Ｂ、およびＰ）を含む原料を、式（３）で表される組成となるように調整してなる原料調合物をまず準備するのが好ましい。 In the melting step, first, a raw material formulation prepared by adjusting a raw material containing an element source (element A, element M, Si, B, and P) to have a composition represented by formula (3) is prepared. Is preferred.
　式（３）において、ａは－０．１≦ａ≦０．４、ｂは０．７≦ｂ≦１．３の範囲である。原料調合物におけるａおよびｂを該範囲にすることによって、目的とする組成を有するケイ酸－ホウ酸－リン酸化合物を製造できる。加えて、原料調合物を良好に溶融でき、均一な溶融物が得られる。また、ｘは０＜ｘ≦０．７、ｙは０＜ｙ≦０．７、０＜（ｘ＋ｙ）≦０．７である。ｘおよびｙを該範囲にすることによって、二次電池用正極材料として用いた多電子型の反応（単位モル数当たり１ｍｏｌを超えるＡを引き抜く反応）を起こすケイ酸－ホウ酸－リン酸化合物を製造することができ、二次電池の理論電気容量を高めることができる。ｘは０＜ｘ＜０．７、ｙは０＜ｙ＜０．７、０＜（ｘ＋ｙ）＜０．７であってもよい。 In the formula (3), a is in the range of −0.1 ≦ a ≦ 0.4, and b is in the range of 0.7 ≦ b ≦ 1.3. By setting a and b in the raw material formulation within this range, a silicic acid-boric acid-phosphoric acid compound having a target composition can be produced. In addition, the raw material formulation can be melted well, and a uniform melt can be obtained. Further, x is 0 <x ≦ 0.7, y is 0 <y ≦ 0.7, and 0 <(x + y) ≦ 0.7. By making x and y within this range, a silicic acid-boric acid-phosphoric acid compound that causes a multi-electron type reaction (reaction that pulls out more than 1 mol per mol) used as a positive electrode material for a secondary battery The theoretical electric capacity of the secondary battery can be increased. x may be 0 <x <0.7, y may be 0 <y <0.7, and 0 <(x + y) <0.7.
　式（３）中、ａおよびｂは、多電子型の反応をより容易に起こさせうることから－０．１≦ａ≦０．３、０．８≦ｂ≦１．３にすることがより好ましい。また、０≦ａ≦０．３、１．０≦ｂ≦１．３にすると、充放電によるケイ酸－ホウ酸－リン酸化合物の構造変化が生じない範囲内で、理論電気容量を高める効果が大きい利点がある。ｘ＝ｙであると、ＰおよびＢの平均価電数が＋４となり、Ｓｉの価電数と等しくなり、価電数の差異による構造の歪みがなくなり、充放電のサイクル特性を向上させうる利点がある。 In the formula (3), a and b can easily cause a multi-electron type reaction, so that −0.1 ≦ a ≦ 0.3 and 0.8 ≦ b ≦ 1.3 are more preferable. preferable. Further, when 0 ≦ a ≦ 0.3 and 1.0 ≦ b ≦ 1.3, the effect of increasing the theoretical electric capacity within a range in which the structural change of the silicic acid-boric acid-phosphoric acid compound due to charge / discharge does not occur. There are great advantages. When x = y, the average valence valence of P and B is +4, which is equal to the valence valence of Si, and there is no distortion of the structure due to the difference in valence number, which can improve the charge / discharge cycle characteristics There is.
　式（３）中、ｃ２１の値は、ａ、ｂ、およびＭの価数Ｎに依存する数である。組成式中の元素の価数は、後の粉砕工程および／または加熱工程で変化しうることから、加熱工程後にｃ２２となる値にｃ２１を調節する。例えば、加熱工程で成分の酸化還元、揮発等によりｃ２１の値が増減する場合には、該増減を考慮に入れた値とするのが好ましい。本発明の製造方法においては、ｃ２１を目的物のｃ２２に対して０．９～１．２倍値としておくのが好ましい。 In formula (3), the value of c21 is a number that depends on the valence N of a, b, and M. Since the valence of the element in the composition formula can be changed in the subsequent pulverization step and / or the heating step, c21 is adjusted to a value that becomes c22 after the heating step. For example, when the value of c21 increases or decreases due to oxidation / reduction or volatilization of the components in the heating step, it is preferable to set the value in consideration of the increase / decrease. In the production method of the present invention, c21 is preferably set to a value 0.9 to 1.2 times the target c22.
　式（３）の元素Ａの好ましい範囲は、式（１）の元素Ａの好ましい範囲と同様である。式（３）の元素Ｍの好ましい範囲は、式（１）の元素Ｍの好ましい範囲と同様である。
　本発明においては、原料調合物の組成を特定の範囲にすることによって溶融工程における溶融を容易にすることができる。 The preferable range of the element A in the formula (3) is the same as the preferable range of the element A in the formula (1). The preferable range of the element M in the formula (3) is the same as the preferable range of the element M in the formula (1).
In the present invention, melting in the melting step can be facilitated by setting the composition of the raw material formulation to a specific range.
　以上、溶融工程（Ｐ１１）における式（１）、および、溶融工程（Ｐ２１）における式（３）について説明したが、溶融工程（Ｐ１）における式（Ａ）についても上記と同様である。すなわち、式（Ａ）のａ、ｂの好ましい範囲は、式（１）のａ、ｂまたは式（３）のａ、ｂの好ましい範囲と同様であり、式（Ａ）のｃ１の好ましい範囲は、式（１）のｃ１１または式（３）のｃ２１の好ましい範囲と同様であり、式（Ａ）のｄの好ましい範囲は、式（１）のｘまたは式（３）のｘ＋ｙの好ましい範囲と同様である。また、式（Ａ）の元素Ａの好ましい範囲は、式（１）の元素Ａの好ましい範囲と同様である。式（Ａ）の元素Ｍの好ましい範囲は、式（１）の元素Ｍの好ましい範囲と同様である。
　溶融工程（Ｐ１）における式（Ａ）のｃ１、溶融工程（Ｐ１１）における式（１）のｃ１１、および、溶融工程（Ｐ２１）における式（３）のｃ２１は、それぞれ、一般には、
　ｃ１＝０．５ａ＋０．５Ｎｂ－１、
　ｃ１１＝０．５ａ＋０．５Ｎｂ－１、
　および
　ｃ２１＝０．５ａ＋０．５Ｎｂ－１
　で表される。また、Ｎは+２価であるのが好ましい。 As mentioned above, although the formula (1) in the melting step (P11) and the formula (3) in the melting step (P21) have been described, the same applies to the formula (A) in the melting step (P1). That is, the preferable ranges of a and b in the formula (A) are the same as the preferable ranges of a and b in the formula (1) or a and b in the formula (3), and the preferable range of c1 in the formula (A) is , C11 in formula (1) or c21 in formula (3) is the same as the preferred range, and d in formula (A) is preferably x in formula (1) or x + y in formula (3). It is the same. Moreover, the preferable range of the element A of Formula (A) is the same as the preferable range of the element A of Formula (1). The preferable range of the element M of the formula (A) is the same as the preferable range of the element M of the formula (1).
In general, c1 of the formula (A) in the melting step (P1), c11 of the formula (1) in the melting step (P11), and c21 of the formula (3) in the melting step (P21) are respectively
c1 = 0.5a + 0.5Nb-1,
c11 = 0.5a + 0.5Nb-1,
And c21 = 0.5a + 0.5Nb-1
It is represented by N is preferably +2 valent.
（原料調合物：元素Ａを含む化合物）
　原料調合物における元素Ａを含む化合物としては、Ａの炭酸塩（Ａ２ＣＯ３）、Ａの炭酸水素塩（ＡＨＣＯ３）、Ａの水酸化物（ＡＯＨ）、Ａのケイ酸塩（Ａ２Ｏ・２ＳｉＯ２、Ａ２Ｏ・ＳｉＯ２、２Ａ２Ｏ・ＳｉＯ２等）、Ａのリン酸塩（Ａ３ＰＯ４）、Ａのリン酸水素塩（Ａ２ＨＰＯ４、ＡＨ２ＰＯ４等）、Ａのホウ酸塩（Ａ２Ｏ・Ｂ２Ｏ３、Ａ２Ｏ・２Ｂ２Ｏ３、Ａ２Ｏ・４Ｂ２Ｏ３等）、Ａの硝酸塩（ＡＮＯ３）、Ａの塩化物（ＡＣｌ）、Ａの硫酸塩（Ａ２ＳＯ４）、Ａの有機酸塩（酢酸塩（ＣＨ３ＣＯＯＡ）およびシュウ酸塩（（ＣＯＯＡ）２）等）からなる群より選ばれる少なくとも１種が好ましい。元素ＡはＬｉが好ましい。さらに、これらの化合物は水和物であってもよい。これらのうち、Ａの炭酸塩や炭酸水素塩は安価であり、また取扱いが容易であるのでより好ましい。 (Raw material formulation: Compound containing element A)
The compound containing element A in the raw material formulation includes A carbonate (A 2 CO 3 ), A hydrogen carbonate (AHCO 3 ), A hydroxide (AOH), and A silicate (A 2 O · 2SiO 2 , A 2 O · SiO 2 , 2A 2 O · SiO 2, etc., A phosphate (A 3 PO 4 ), A hydrogen phosphate (A 2 HPO 4 , AH 2 PO 4 etc.) ), A borate (A 2 O · B 2 O 3 , A 2 O · 2B 2 O 3 , A 2 O · 4B 2 O 3, etc.), A nitrate (ANO 3 ), A chloride ( ACl), sulfate of A (A 2 SO 4 ), organic acid salt of A (acetate (CH 3 COOA) and oxalate ((COOA) 2 ), etc.) are preferred. . The element A is preferably Li. Furthermore, these compounds may be hydrates. Of these, carbonates and bicarbonates of A are more preferred because they are inexpensive and easy to handle.
（原料調合物：元素Ｍを含む化合物）
　原料調合物における元素Ｍを含む化合物としては、Ｍの酸化物（ＦｅＯ、Ｆｅ３Ｏ４、Ｆｅ２Ｏ３、ＭｎＯ、Ｍｎ２Ｏ３、ＭｎＯ２、ＣｏＯ、Ｃｏ３Ｏ４、Ｃｏ２Ｏ３、ＮｉＯ等）、Ｍのオキシ水酸化物（ＭＯ（ＯＨ）等）、Ｍのケイ酸塩（ＭＯ・ＳｉＯ２、２ＭＯ・ＳｉＯ２等）、Ｍのリン酸塩（ＭＰＯ４、Ｍ２Ｐ２Ｏ７等）、Ｍのホウ酸塩（ＭＢＯ３、Ｍ２Ｂ２Ｏ５等）、金属Ｍ、Ｍの塩化物（ＭＣｌ２、ＭＣｌ３）、Ｍの硝酸塩（Ｍ（ＮＯ３）２、Ｍ（ＮＯ３）３）、Ｍの硫酸塩（ＭＳＯ４、Ｍ２（ＳＯ４）３）、Ｍの有機酸塩（酢酸塩（Ｍ（ＣＨ３ＣＯＯ）２）およびシュウ酸塩（Ｍ（ＣＯＯ）２）等）からなる群より選ばれる少なくとも１種が好ましい。元素Ｍを含む化合物としては、入手のしやすさやコストから、Ｆｅ３Ｏ４、Ｆｅ２Ｏ３、ＭｎＯ、Ｍｎ２Ｏ３、ＭｎＯ２、Ｃｏ３Ｏ４、およびＮｉＯからなる群より選ばれる少なくとも１種がより好ましく、Ｆｅ３Ｏ４、Ｆｅ２Ｏ３、およびＭｎＯ２からなる群より選ばれる少なくとも１種が特に好ましい。Ｆｅ３Ｏ４、Ｆｅ２Ｏ３、およびＭｎＯ２は１種のみを用いても、２種以上を用いてもよい。 (Raw material formulation: Compound containing element M)
As the compound containing the element M in the raw material preparation, oxides of M (FeO, Fe 3 O 4 , Fe 2 O 3 , MnO, Mn 2 O 3 , MnO 2 , CoO, Co 3 O 4 , Co 2 O 3 , NiO, etc.), M oxyhydroxide (MO (OH), etc.), M silicate (MO · SiO 2 , 2MO · SiO 2 etc.), M phosphate (MPO 4 , M 2 P 2) O 7 etc.), M borate (MBO 3 , M 2 B 2 O 5 etc.), metal M, M chloride (MCl 2 , MCl 3 ), M nitrate (M (NO 3 ) 2 , M (NO 3 ) 3 ), M sulfate (MSO 4 , M 2 (SO 4 ) 3 ), M organic acid salt (acetate (M (CH 3 COO) 2 ) and oxalate (M (COO) 2 ) etc.) is preferably selected from the group consisting of. The compound containing the element M is at least selected from the group consisting of Fe 3 O 4 , Fe 2 O 3 , MnO, Mn 2 O 3 , MnO 2 , Co 3 O 4 , and NiO because of availability and cost. One type is more preferable, and at least one selected from the group consisting of Fe 3 O 4 , Fe 2 O 3 , and MnO 2 is particularly preferable. Fe 3 O 4 , Fe 2 O 3 , and MnO 2 may be used alone or in combination of two or more.
（原料調合物：Ｓｉ（ケイ素）を含む化合物）
　原料調合物におけるＳｉを含む化合物としては、酸化ケイ素（ＳｉＯ２）、Ａのケイ酸塩、Ｍのケイ酸塩、およびケイ素のアルコキシド（Ｓｉ（ＯＣＨ３）４、Ｓｉ（ＯＣ２Ｈ５）４等）からなる群より選ばれる少なくとも１種が好ましく、酸化ケイ素が安価であるので特に好ましい。Ｓｉを含む化合物は、結晶質であっても、非晶質であってもよい。 (Raw material preparation: Compound containing Si (silicon))
The compound containing Si in the raw material preparation includes silicon oxide (SiO 2 ), A silicate, M silicate, and silicon alkoxide (Si (OCH 3 ) 4 , Si (OC 2 H 5 ) 4. Etc.) is preferred, and silicon oxide is particularly preferred because it is inexpensive. The compound containing Si may be crystalline or amorphous.
（原料調合物：Ｂ（ホウ素）を含む化合物）
　原料調合物におけるＢを含む化合物としては、酸化ホウ素（Ｂ２Ｏ３）、ホウ酸（Ｈ３ＢＯ３）、Ａのホウ酸塩、Ｍのホウ酸塩、およびリン酸ホウ素（Ｂ２Ｏ３・Ｐ２Ｏ５）からなる群より選ばれる少なくとも１種が好ましく、酸化ホウ素およびホウ酸からなる群より選ばれる少なくとも１種が安価であるため特に好ましい。 (Raw material formulation: Compound containing B (boron))
Compounds containing B in the raw material formulation include boron oxide (B 2 O 3 ), boric acid (H 3 BO 3 ), A borate, M borate, and boron phosphate (B 2 O 3). • At least one selected from the group consisting of P 2 O 5 ) is preferable, and at least one selected from the group consisting of boron oxide and boric acid is particularly preferable because it is inexpensive.
（原料調合物：Ｐ（リン）を含む化合物）
　原料調合物におけるＰを含む化合物としては、酸化リン（Ｐ２Ｏ５）、リン酸アンモニウム（（ＮＨ４）３ＰＯ４）、リン酸水素アンモニウム（（ＮＨ４）２ＨＰＯ４、ＮＨ４Ｈ２ＰＯ４）、Ａのリン酸塩、Ｍのリン酸塩、リン酸ホウ素（Ｂ２Ｏ３・Ｐ２Ｏ５）、リン酸（Ｈ３ＰＯ４）、ポリリン酸（Ｈ（ｎ＋２）ＰｎＯ（３ｎ＋１））、亜リン酸（Ｈ３ＰＯ３）および次亜リン酸（Ｈ３ＰＯ２）等からなる群より選ばれる少なくとも１種が好ましい。安価かつ取扱いが容易な点で、リン酸水素アンモニウムおよびリン酸ホウ素からなる群より選ばれる少なくとも１種がより好ましい。Ａのリン酸塩としては、Ｌｉ３ＰＯ４が好ましく、Ｍのリン酸塩としては、Ｆｅ３（ＰＯ４）２、ＦｅＰＯ４、およびＭｎ３（ＰＯ４）２からなる群より選ばれる少なくとも１種が好ましい。 (Raw material formulation: Compound containing P (phosphorus))
As the compound containing P in the raw material preparation, phosphorus oxide (P 2 O 5 ), ammonium phosphate ((NH 4 ) 3 PO 4 ), ammonium hydrogen phosphate ((NH 4 ) 2 HPO 4 , NH 4 H 2 PO 4 ), A phosphate, M phosphate, boron phosphate (B 2 O 3 .P 2 O 5 ), phosphoric acid (H 3 PO 4 ), polyphosphoric acid (H (n + 2) P n O (3n + 1) ), phosphorous acid (H 3 PO 3 ), hypophosphorous acid (H 3 PO 2 ) and the like are preferred. In view of being inexpensive and easy to handle, at least one selected from the group consisting of ammonium hydrogen phosphate and boron phosphate is more preferable. The phosphate of A is preferably Li 3 PO 4 , and the phosphate of M is at least 1 selected from the group consisting of Fe 3 (PO 4 ) 2 , FePO 4 , and Mn 3 (PO 4 ) 2. Species are preferred.
（原料調合物の好適な組み合わせ）
　ケイ酸－ホウ酸化合物の製造方法において、原料調合物としては、Ａの炭酸塩または炭酸水素塩；Ｍの酸化物または元素Ｍのオキシ水酸化物；酸化ケイ素；および酸化ホウ素またはホウ酸の組み合わせが好ましい。
　さらに原料調合物としては、Ｌｉ２ＣＯ３またはＬｉＨＣＯ３；Ｆｅ３Ｏ４、Ｆｅ２Ｏ３、およびＭｎＯ２からなる群より選ばれる１種以上の化合物；ＳｉＯ２；およびＢ２Ｏ３の組み合わせが特に好ましい。 (Preferred combination of raw material formulations)
In the method for producing a silicic acid-boric acid compound, the raw material preparation includes a carbonate or hydrogen carbonate of A; an oxide of M or an oxyhydroxide of element M; a silicon oxide; and a combination of boron oxide or boric acid Is preferred.
Still raw material formulation, Li 2 CO 3 or LiHCO 3; combination of and B 2 O 3; Fe 3 O 4, Fe 2 O 3, and one or more compounds selected from the group consisting of MnO 2; SiO 2 Is particularly preferred.
　ケイ酸－ホウ酸化合物－リン酸化合物の製造方法において、原料調合物としては、Ａの炭酸塩または炭酸水素塩；Ｍの酸化物または元素Ｍのオキシ水酸化物；酸化ケイ素；酸化ホウ素、ホウ酸またはリン酸ホウ素；およびリン酸水素アンモニウムまたはリン酸ホウ素の組み合わせが好ましい。
　さらに原料調合物としては、Ｌｉ２ＣＯ３またはＬｉＨＣＯ３；Ｆｅ３Ｏ４、Ｆｅ２Ｏ３、およびＭｎＯ２からなる群より選ばれる１種以上の化合物；ＳｉＯ２；Ｂ２Ｏ３；ＮＨ４Ｈ２ＰＯ４の組み合わせが特に好ましい。 In the method for producing a silicic acid-boric acid compound-phosphoric acid compound, raw material preparations include A carbonate or hydrogen carbonate; M oxide or element M oxyhydroxide; silicon oxide; boron oxide, boron A combination of acid or boron phosphate; and ammonium hydrogen phosphate or boron phosphate is preferred.
Still raw material formulation, Li 2 CO 3 or LiHCO 3; Fe 3 O 4, Fe 2 O 3, and one or more compounds selected from the group consisting of MnO 2; SiO 2; B 2 O 3; NH 4 A combination of H 2 PO 4 is particularly preferred.
　原料調合物の組成は、ケイ酸－ホウ酸化合物の製造およびケイ酸－ホウ酸－リン酸化合物の製造において、原則として、溶融物の組成と対応させる。ただし、該原料調合物中に、溶融工程中に揮発等により失われやすい成分、例えばＬｉ、Ｐ、Ｂ等、を存在させた場合には、得られる溶融物の組成は原料調合物の組成と相違する場合がある。そのような場合には、揮発等により失われる量を考慮して、原料調合物の組成を適宜変更するのが好ましい。 In principle, the composition of the raw material formulation corresponds to the composition of the melt in the production of the silicic acid-boric acid compound and the silicic acid-boric acid-phosphoric acid compound. However, in the raw material formulation, when a component that is easily lost due to volatilization or the like during the melting step, such as Li, P, B, etc., is present, the composition of the obtained melt is the same as the composition of the raw material formulation. There may be differences. In such a case, it is preferable to appropriately change the composition of the raw material formulation in consideration of the amount lost due to volatilization or the like.
　原料調合物に含ませる各原料の純度は特に限定されない。反応性や二次電池用正極材料の特性等を考慮すると、水和水を除く純度が９９質量％以上であることが好ましい。 The purity of each raw material included in the raw material preparation is not particularly limited. Considering reactivity, characteristics of the positive electrode material for secondary batteries, and the like, the purity excluding hydrated water is preferably 99% by mass or more.
（溶融工程の実施条件）
　本発明における溶融工程は、式（Ｂ）で表される組成、式（１）で表される組成、または式（３）で表される組成、を有する溶融物を得る工程である。該工程は、前記の原料調合物を加熱して溶融させることにより実施するのが好ましい。溶融を行う前に、各原料、または、原料調合物を、ミキサー、ボールミル、ジェットミル、または遊星ミル等を用いて、乾式または湿式で粉砕および／または混合することが好ましい。各原料調合物中の原料の粒度は、混合操作、原料調合物の溶融容器への充填操作、原料調合物の溶融性等に悪影響を及ぼさない範囲であれば、限定されない。 (Conditions for melting process)
The melting step in the present invention is a step of obtaining a melt having a composition represented by formula (B), a composition represented by formula (1), or a composition represented by formula (3). This step is preferably carried out by heating and melting the raw material formulation. Prior to melting, each raw material or raw material preparation is preferably pulverized and / or mixed dry or wet using a mixer, ball mill, jet mill, planetary mill or the like. The particle size of the raw material in each raw material preparation is not limited as long as it does not adversely affect the mixing operation, the filling operation of the raw material preparation into the melting container, the meltability of the raw material preparation, and the like.
　次に、原料調合物は容器等に入れて加熱することが好ましい。加熱は該容器を加熱炉に入れて行うことが好ましい。容器は、アルミナ製、カーボン製、炭化ケイ素製、ホウ化ジルコニウム製、ホウ化チタン製、窒化ホウ素製、炭素製、白金製、またはロジウムを含む白金合金製等が好ましい。耐火物系練瓦、還元材料（例えばグラファイト）からなる容器も採用できる。さらに、加熱炉内に揮発および蒸発防止のために、容器に蓋を装着して溶融することが好ましい。加熱炉は、抵抗加熱炉、高周波誘導炉、またはプラズマアーク炉が好ましい。抵抗加熱炉はニクロム合金等の合金製、炭化ケイ素製、またはケイ化モリブデン製の発熱体を備えた電気炉であることが好ましい。 Next, it is preferable to heat the raw material mixture in a container or the like. Heating is preferably performed by placing the container in a heating furnace. The container is preferably made of alumina, carbon, silicon carbide, zirconium boride, titanium boride, boron nitride, carbon, platinum, or a platinum alloy containing rhodium. A container made of a refractory-based brick and a reducing material (eg, graphite) can also be employed. Furthermore, in order to prevent volatilization and evaporation in the heating furnace, it is preferable to attach a lid to the container and melt it. The heating furnace is preferably a resistance heating furnace, a high frequency induction furnace, or a plasma arc furnace. The resistance heating furnace is preferably an electric furnace provided with a heating element made of an alloy such as a nichrome alloy, silicon carbide, or molybdenum silicide.
　溶融工程は、空気中、不活性ガス中または還元ガス中で実施することが好ましい。溶融の条件は、容器または加熱炉の種類や熱源等の加熱方法等の条件により、適宜変更できる。圧力は、常圧、加圧、減圧（０．９×１０５Ｐａ以下）のいずれであってもよい。還元ガス中が好ましいが、酸化ガス中であってもよい。酸化ガス中であった場合には、次工程の加熱工程において還元（例えばＭ３＋からＭ２＋への変化）を行うことができる。
　不活性ガス中とは、窒素ガス（Ｎ２）、およびヘリウムガス（Ｈｅ）およびアルゴンガス（Ａｒ）等の希ガスからなる群より選ばれる少なくとも１種の不活性ガスを９９体積％以上含む気体条件であることをいう。還元ガス中とは、上記した不活性ガスに、還元性を有する気体を添加し、実質に酸素を含まない気体条件であることをいう。還元性を有する気体としては、水素ガス（Ｈ２）、一酸化炭素ガス（ＣＯ）およびアンモニアガス（ＮＨ３）等が挙げられる。不活性ガス中の還元性を有する気体の量は、全気体中に還元性を有する気体が０．１体積％以上であるのが好ましく、１～１０体積％が特に好ましい。酸素の含有量は、該気体中に１体積％以下が好ましく、０．１体積％以下が特に好ましい。 The melting step is preferably performed in air, in an inert gas, or in a reducing gas. Melting conditions can be changed as appropriate depending on conditions such as the type of container or heating furnace and the heating method such as a heat source. The pressure may be any of normal pressure, pressurization, and reduced pressure (0.9 × 10 5 Pa or less). Although it is preferably in reducing gas, it may be in oxidizing gas. If it is in the oxidizing gas, reduction (for example, change from M 3+ to M 2+ ) can be performed in the heating step of the next step.
In the inert gas is a gas containing 99% by volume or more of at least one inert gas selected from the group consisting of nitrogen gas (N 2 ) and rare gases such as helium gas (He) and argon gas (Ar). It is a condition. The term “in the reducing gas” refers to a gas condition in which a reducing gas is added to the inert gas and substantially does not contain oxygen. Examples of the reducing gas include hydrogen gas (H 2 ), carbon monoxide gas (CO), and ammonia gas (NH 3 ). The amount of the reducing gas in the inert gas is preferably 0.1% by volume or more, and particularly preferably 1 to 10% by volume of the reducing gas in the total gas. The oxygen content in the gas is preferably 1% by volume or less, particularly preferably 0.1% by volume or less.
　溶融工程における加熱温度は、１，３００～１，６００℃が好ましく、１，４００～１，５５０℃が特に好ましい。ここで、溶融とは各原料が融解し、目視で透明な状態となることをいう。加熱温度が上記範囲の下限値以上であると溶融が容易になり、上記範囲の上限値以下であると原料の揮発がしにくくなる。加熱時間は０．２～２時間が好ましく、０．５～２時間が特に好ましい。該時間とすることにより溶融物の均一性が充分になり、また原料が揮発しにくい。
　溶融工程においては、溶融物の均一性を上げるために撹拌してもよい。また、次の冷却工程を行うまで、加熱温度より低い温度で溶融物を清澄させてもよい。さらに、溶融工程で得た溶融物は、次の冷却工程に悪影響を与えない限り、該冷却工程前に他の工程を行ってもよい。 The heating temperature in the melting step is preferably 1,300 to 1,600 ° C., particularly preferably 1,400 to 1,550 ° C. Here, melting means that each raw material is melted and is in a transparent state visually. When the heating temperature is equal to or higher than the lower limit value of the above range, melting becomes easy, and when the heating temperature is equal to or lower than the upper limit value of the above range, the raw material is hardly volatilized. The heating time is preferably 0.2 to 2 hours, particularly preferably 0.5 to 2 hours. By setting the time, the homogeneity of the melt is sufficient, and the raw material is difficult to volatilize.
In the melting step, stirring may be performed to increase the uniformity of the melt. Further, the melt may be clarified at a temperature lower than the heating temperature until the next cooling step is performed. Further, the melt obtained in the melting step may be subjected to other steps before the cooling step as long as it does not adversely affect the next cooling step.
［冷却工程（Ｐ２）、（Ｐ１２）、（Ｐ２２）］
　冷却工程は、溶融工程で得た溶融物を室温付近まで冷却して固化物を得る工程である。固化物は非晶質物であることが好ましいが、固化物の一部は結晶化物であってもよい。固化物が非晶質物を含むことにより、次工程の粉砕工程が実施しやすくなり、ケイ酸化合物の組成および粒度を制御しやすくなる。さらに、後工程の加熱工程において、生成物が塊状になるのを防ぐことができ、かつ、生成物の粒度が制御しやすくなる利点がある。
　固化物が結晶化物を含む場合、後工程の加熱工程で結晶化物が結晶核となり、結晶化しやすくなる。固化物中の結晶化物量は固化物の全質量に対して０～３０質量％であることが好ましい。結晶化物を多く含むと粒状やフレーク状の固化物を得ることが困難となる。また、冷却機器の損耗を早め、その後の粉砕工程の負担が大きくなる。 [Cooling step (P2), (P12), (P22)]
The cooling step is a step of obtaining a solidified product by cooling the melt obtained in the melting step to near room temperature. The solidified product is preferably an amorphous material, but a part of the solidified product may be a crystallized product. When the solidified product contains an amorphous material, the next pulverization step can be easily performed, and the composition and particle size of the silicate compound can be easily controlled. Furthermore, there is an advantage that the product can be prevented from being agglomerated in the subsequent heating step, and the particle size of the product can be easily controlled.
In the case where the solidified product contains a crystallized product, the crystallized product becomes a crystal nucleus in the heating step in the subsequent step, and crystallization is facilitated. The amount of crystallized product in the solidified product is preferably 0 to 30% by mass with respect to the total mass of the solidified product. When a large amount of crystallized material is contained, it becomes difficult to obtain a granular or flaky solidified material. Further, the wear of the cooling device is accelerated, and the burden of the subsequent pulverization process is increased.
　冷却工程は設備等の点から空気中で行うことが好ましい。また冷却工程を不活性ガス中または還元ガス中で行ってもよい。溶融物の冷却速度は－１×１０３℃／秒以上が好ましく、－１×１０４℃／秒以上が特に好ましい。本明細書では、冷却する場合の単位時間当たりの温度変化（すなわち冷却速度）を負の値で示し、加熱する場合の単位時間当たりの温度変化（すなわち加熱速度）を正の値で示す。冷却速度を該値以上にすると非晶質物が得られやすい。冷却速度の上限値は製造設備や大量生産性の点からは－１×１０１０℃／秒程度が好ましく、実用性の点からは－１×１０８℃／秒が特に好ましい。溶融物の冷却速度は１０００℃から５０℃までの冷却速度を－１０３℃／秒～－１０１０℃／秒とすることが特に好ましい。 The cooling step is preferably performed in air from the viewpoint of equipment and the like. The cooling step may be performed in an inert gas or a reducing gas. The cooling rate of the melt is preferably not less than -1 × 10 3 ℃ / sec, -1 × 10 4 ℃ / sec or more is particularly preferable. In the present specification, a temperature change per unit time (ie, cooling rate) in the case of cooling is indicated by a negative value, and a temperature change per unit time in case of heating (ie, the heating rate) is indicated by a positive value. When the cooling rate is higher than this value, an amorphous material is easily obtained. The upper limit of the cooling rate is preferably about −1 × 10 10 ° C./second from the viewpoint of manufacturing equipment and mass productivity, and is particularly preferably −1 × 10 8 ° C./second from the viewpoint of practicality. The cooling rate of the melt is particularly preferably from -10 3 ° C / second to -10 10 ° C / second from 1000 ° C to 50 ° C.
　溶融物の冷却方法は、例えば高速で回転する双ローラの間に溶融物を滴下してフレーク状の固化物を得る方法、回転する単ローラに溶融物を滴下してフレーク状もしくは板状の固化物を掃引して得る方法、または溶融物を冷却したカーボン板や金属板にプレスして塊状の固化物を得る方法であることが好ましい。なかでも、双ローラを用いた冷却方法が、冷却速度が速く、大量に処理できるのでより好ましい。双ローラとしては、金属製、カーボン製、またはセラミックス製のものを用いることが好ましい。 The method of cooling the melt is, for example, a method in which a melt is dropped between twin rollers rotating at high speed to obtain a flake-like solidified product, or a melt is dropped on a rotating single roller to form a flake-like or plate-like solidified product. It is preferable that the method is obtained by sweeping an object, or a method in which a melt is pressed on a cooled carbon plate or metal plate to obtain a lump solidified product. Among these, a cooling method using twin rollers is more preferable because the cooling rate is high and a large amount of processing can be performed. As the double roller, it is preferable to use one made of metal, carbon, or ceramic.
　冷却方法としては、溶融物を水に直接投入する方法もあるが、該方法は、制御が難しく、冷却速度は－１×１０℃／秒～－１×１０２℃／秒程度であり、非晶質物質を得るのが難しい。また固化物が塊状となり、粉砕に多くの労力を要する。冷却方法として、液体窒素に溶融物を直接投入する方法もあり、水の場合よりも冷却速度を速くできるが、水を使用する方法と同様の問題があり、また、高コストである。 As a cooling method, there is a method in which the melt is directly poured into water, but this method is difficult to control, and the cooling rate is about −1 × 10 ° C./second to −1 × 10 2 ° C./second. Difficult to obtain crystalline material. Further, the solidified product becomes a lump and requires a lot of labor for pulverization. As a cooling method, there is also a method in which a melt is directly charged into liquid nitrogen, and the cooling rate can be made faster than in the case of water. However, there are problems similar to the method using water, and the cost is high.
　冷却工程で得られる固化物は、フレーク状または繊維状が好ましい。フレーク状の固化物としては、平均厚さが２００μｍ以下が好ましく、１００μｍ以下が特に好ましい。フレーク状の固化物としての、平均厚さに垂直の面の平均直径は、特に限定されない。繊維状の固化物としては、平均直径が５０μｍ以下が好ましく、３０μｍ以下が特に好ましい。平均厚さや平均直径の上限値以下であると、次工程の粉砕工程の手間を軽減することができ、結晶化効率を高くすることができる。平均厚さおよび平均直径は、ノギスやマイクロメータにより測定することができる。また、平均直径は、顕微鏡観察により測定することもできる。
　冷却工程で得た固化物は、次の粉砕工程に悪影響を与えない限り、該粉砕工程前に他の工程を行ってもよい。 The solidified product obtained in the cooling step is preferably flaky or fibrous. The flaky solidified product preferably has an average thickness of 200 μm or less, particularly preferably 100 μm or less. The average diameter of the plane perpendicular to the average thickness as the flaky solidified product is not particularly limited. The fibrous solidified product preferably has an average diameter of 50 μm or less, particularly preferably 30 μm or less. When the average thickness or the average diameter is not more than the upper limit of the average diameter, labor of the next pulverization step can be reduced and crystallization efficiency can be increased. The average thickness and average diameter can be measured with a caliper or a micrometer. The average diameter can also be measured by microscopic observation.
The solidified product obtained in the cooling step may be subjected to another step before the pulverization step as long as it does not adversely affect the next pulverization step.
［粉砕工程（Ｐ３）、（Ｐ１３）、（Ｐ２３）］
　粉砕工程とは、冷却工程で得た固化物を粉砕して粉砕物を得る工程である。固化物は通常の場合、非晶質物を多く含む、または、非晶質物からなるため、粉砕がしやすい利点がある。また粉砕に使用する装置に負担をかけずに粉砕ができかつ粒径の制御がしやすい利点がある。一方、従来の固相反応は、加熱工程の後で粉砕を行うが、粉砕によって残留応力が生じ、電池特性を悪化させる問題があることに本発明者は気づいた。よって、本発明の製造方法では、加熱工程の前に粉砕し、生じた残留応力は、後工程の加熱工程で低減または除去する方法を採用する。 [Crushing step (P3), (P13), (P23)]
The pulverization step is a step of pulverizing the solidified product obtained in the cooling step to obtain a pulverized product. Since the solidified product usually contains a large amount of amorphous material or consists of an amorphous material, there is an advantage that it is easy to grind. Further, there is an advantage that grinding can be performed without imposing a burden on an apparatus used for grinding and the particle size can be easily controlled. On the other hand, in the conventional solid phase reaction, pulverization is performed after the heating step, but the present inventor has noticed that there is a problem that residual stress is generated by the pulverization and battery characteristics are deteriorated. Therefore, in the manufacturing method of the present invention, a method is adopted in which the residual stress generated by pulverization before the heating step is reduced or removed in the heating step in the subsequent step.
　粉砕は、ジョークラッシャー、ハンマーミル、ボールミル、ジェットミル、遊星ミル等を用いて行うことが好ましい。粉砕の方式は、乾式または湿式のいずれであってもよい。粉砕工程の前に固化物を手揉みやハンマー等で叩いて予備的に細かくすると、粉砕工程の負担が軽減するので好ましい。粉砕を湿式で行った場合、分散媒を沈降、濾過、減圧乾燥、加熱乾燥等で除去した後に、加熱工程を実施するのが好ましい。ただし、分散媒が少ない場合、特に粉砕物の質量に占める固形分の質量の割合が３０％以上の場合、分散媒を含んだ粉砕物のままで加熱工程を行ってもよい。 The pulverization is preferably performed using a jaw crusher, a hammer mill, a ball mill, a jet mill, a planetary mill or the like. The method of pulverization may be either dry or wet. It is preferable to preliminarily make the solidified material fine by hitting it with a hammer or a hammer before the pulverization step, since the burden on the pulverization step is reduced. When the pulverization is performed in a wet manner, it is preferable to carry out the heating step after removing the dispersion medium by sedimentation, filtration, drying under reduced pressure, drying by heating, or the like. However, when there are few dispersion media, especially when the ratio of the mass of solid content to the mass of the pulverized product is 30% or more, the heating step may be carried out with the pulverized product containing the dispersion medium as it is.
　本発明におけるケイ酸化合物は絶縁物質であることから、二次電池用正極材料として用いる場合には、固化物に導電材を含ませるのが好ましい。また、二次電池用正極材料として用いる場合には、微粒子状であるのが好ましい。粉砕物の平均粒径は、体積換算のメディアン径で１０ｎｍ～１０μｍが好ましく、１０ｎｍ～５μｍが特に好ましい。粒径の測定は、沈降法やレーザ回折／散乱式粒子径測定装置で測定できる。粉砕物の粒径が小さい場合には、還元反応が促進され、加熱工程の加熱温度や時間を低減できるため好ましい。粉砕物の平均粒径を上記範囲とすることにより、粉砕工程および加熱工程の作業性を向上させ、加熱工程の生成物の平均粒径を制御しやすくなる利点がある。 Since the silicic acid compound in the present invention is an insulating material, when used as a positive electrode material for a secondary battery, it is preferable to include a conductive material in the solidified product. Moreover, when using as a positive electrode material for secondary batteries, it is preferable that it is a fine particle form. The average particle diameter of the pulverized product is preferably 10 nm to 10 μm, and particularly preferably 10 nm to 5 μm, in terms of volume-based median diameter. The particle size can be measured by a sedimentation method or a laser diffraction / scattering particle size measuring device. When the particle size of the pulverized product is small, the reduction reaction is promoted, and the heating temperature and time of the heating step can be reduced, which is preferable. By setting the average particle size of the pulverized product in the above range, there is an advantage that the workability of the pulverization step and the heating step is improved and the average particle size of the product of the heating step can be easily controlled.
　導電材としては、有機化合物および炭素粉末からなる群より選ばれる少なくとも１種の炭素源が好ましい。有機化合物および炭素粉末からなる群より選ばれる少なくとも１種の炭素源の量は、該炭素源中の炭素換算量（質量）が、固化物の質量と、該炭素源中の炭素換算量（質量）との合計質量に対して、０．１～２０質量％となる量が好ましく、２～１０質量％となる量が特に好ましい。炭素量を上記範囲とすることにより、二次電池用正極材料としての導電性を充分に高めることができる。
　固化物に含ませた有機化合物および炭素粉末は、粉砕工程や加熱工程における酸化を防止し、さらに還元を促進する。また、有機化合物および炭素粉末は、加熱工程後に残り、導電材として機能する。よって、二次電池用正極材料の導電性を高めることができる。 The conductive material is preferably at least one carbon source selected from the group consisting of organic compounds and carbon powder. The amount of at least one carbon source selected from the group consisting of an organic compound and carbon powder is such that the carbon equivalent amount (mass) in the carbon source is the mass of the solidified product and the carbon equivalent amount (mass in the carbon source). ) In an amount of 0.1 to 20% by mass, particularly preferably 2 to 10% by mass. By setting the amount of carbon in the above range, the conductivity as the positive electrode material for secondary batteries can be sufficiently increased.
The organic compound and carbon powder contained in the solidified product prevent oxidation in the pulverization step and heating step, and further promote reduction. The organic compound and carbon powder remain after the heating step and function as a conductive material. Therefore, the conductivity of the positive electrode material for secondary batteries can be increased.
　有機化合物としては、糖類、アミノ酸類、ペプチド類、アルデヒド類、ケトン類、グリコール類、ポリビニルアルコール、および脂肪酸からなる群より選ばれる少なくとも１種が好ましく、糖類、グリコール類、またはポリビニルアルコールが特に好ましい。糖類としては、グルコース、フラクトース、およびガラクトース等の単糖類、スクロース、マルトース、セロビオース、およびトレハロース等のオリゴ糖、転化糖、デキストリン、アミロース、アミロペクチン、およびセルロース等の多糖類、ならびにアスコルビン酸等が挙げられる。アミノ酸類としては、アラニン、グリシン等のアミノ酸が挙げられる。ペプチド類としては、分子量が１，０００以下の低分子ペプチドが挙げられる。
　炭素粉末としては、カーボンブラック、グラファイト、アセチレンブラック等が好ましい。また、炭素粉末は繊維状炭素または板状炭素であってもよい。 As the organic compound, at least one selected from the group consisting of saccharides, amino acids, peptides, aldehydes, ketones, glycols, polyvinyl alcohol, and fatty acids is preferable, and saccharides, glycols, or polyvinyl alcohol is particularly preferable. . Examples of the saccharide include monosaccharides such as glucose, fructose, and galactose, oligosaccharides such as sucrose, maltose, cellobiose, and trehalose, invert sugar, polysaccharides such as dextrin, amylose, amylopectin, and cellulose, and ascorbic acid. It is done. Examples of amino acids include amino acids such as alanine and glycine. Peptides include low molecular weight peptides having a molecular weight of 1,000 or less.
As the carbon powder, carbon black, graphite, acetylene black and the like are preferable. The carbon powder may be fibrous carbon or plate-like carbon.
　粉砕工程において、固化物に有機化合物や炭素粉末を含ませて粉砕した場合には、加熱工程後に、導電材を混合する工程を省略できる利点がある。また、有機化合物や炭素粉末は、固化物の粒成長を抑制しうる。固化物に有機化合物を含ませる場合の粉砕工程には、粉砕物の表面に均一に分散させるために、湿式粉砕を採用するのが好ましい。粉砕する際の分散媒としては、水、または、エタノール、イソプロピルアルコール、アセトン、ヘキサン、トルエン等の有機溶媒を用いることができる。なかでも、水は安価であるために好ましい。固化物に炭素粉末を含ませる場合の粉砕工程には、乾式が好ましい。 In the pulverization step, when the solidified product is pulverized with an organic compound or carbon powder, there is an advantage that the step of mixing the conductive material after the heating step can be omitted. Moreover, the organic compound and carbon powder can suppress the grain growth of the solidified product. In the pulverization step in the case where the organic compound is included in the solidified product, wet pulverization is preferably employed in order to uniformly disperse the pulverized product on the surface. As a dispersion medium for pulverization, water or an organic solvent such as ethanol, isopropyl alcohol, acetone, hexane, or toluene can be used. Of these, water is preferable because it is inexpensive. A dry method is preferable for the pulverization step when the solidified product contains carbon powder.
　さらに、粉砕工程で得た粉砕物は、次の加熱工程に悪影響を与えない限り、該加熱工程前に他の工程を行ってもよい。 Furthermore, the pulverized product obtained in the pulverization step may be subjected to another step before the heating step as long as it does not adversely affect the next heating step.
　［加熱工程（Ｐ４）、（Ｐ１４）、（Ｐ２４）］
　加熱工程は、粉砕工程で得た粉砕物を加熱する工程である。
　加熱工程（Ｐ４）では、下式（Ｂ）で表される組成を有するケイ酸－ホウ酸化合物を得る。
　Ａ２－ｄ＋ａＭｂＳｉ１－ｄＤｄＯ４－ｄ＋ｃ２　　　　（Ｂ）
（式中、Ａ、Ｍ、Ｄ，ａ、ｂ、およびｄは前記と同じ意味を示すが、式（Ａ）における値とは独立した値をとり、ｃ１２はａ、ｂ、およびＭの価数Ｎに依存する数である。） [Heating Steps (P4), (P14), (P24)]
The heating step is a step of heating the pulverized product obtained in the pulverization step.
In the heating step (P4), a silicic acid-boric acid compound having a composition represented by the following formula (B) is obtained.
A 2-d + a M b Si 1-d D d O 4-d + c2 (B)
(In the formula, A, M, D, a, b, and d have the same meaning as described above, but take an independent value from the value in formula (A), and c12 is the valence of a, b, and M. The number depends on N.)
　式（Ｂ）のｃ２の値は、ａ、ｂ、およびＭの価数Ｎに依存する数であり、一般にはｃ２＝０．５ａ＋０．５Ｎｂ－１で表される。また、Ｎは+２価であるのが好ましい。 The value of c2 in the formula (B) is a number that depends on the valence N of a, b, and M, and is generally represented by c2 = 0.5a + 0.5Nb-1. N is preferably +2 valent.
　加熱工程（Ｐ１４）では、下式（２）で表される組成を有するケイ酸－ホウ酸化合物を得る。
　Ａ２－ｘ＋ａＭｂＳｉ１－ｘＢｘＯ４－ｘ＋ｃ１２　　　　　（２）
（式中、Ａ、Ｍ、ａ、ｂ、およびｘは前記と同じ意味を示すが、式（１）における値とは独立した値をとり、ｃ１２はａ、ｂ、およびＭの価数Ｎに依存する数である。） In the heating step (P14), a silicic acid-boric acid compound having a composition represented by the following formula (2) is obtained.
A 2-x + a M b Si 1-x B x O 4-x + c12 (2)
(In the formula, A, M, a, b, and x have the same meaning as described above, but take a value independent of the value in the formula (1), and c12 represents the valence N of a, b, and M. Depends on the number.)
　式（２）のｃ１２の値は、ａ、ｂ、およびＭの価数Ｎに依存する数であり、例えばａ＝０、ｂ＝１およびＮ＝＋２であればｃ１２＝０であり、一般にはｃ１２＝０．５ａ＋０．５Ｎｂ－１で表される。また、Ｎは+２価であるのが好ましい。 The value of c12 in equation (2) is a number that depends on the valence N of a, b, and M. For example, if a = 0, b = 1, and N = + 2, c12 = 0. c12 = 0.5a + 0.5Nb−1. N is preferably +2 valent.
　加熱工程（Ｐ２４）では、下式（４）で表される組成を有するケイ酸－ホウ酸－リン酸化合物を得る。
　Ａ２－ｘ－ｙ＋ａＭｂＳｉ１－（ｘ＋ｙ）ＢｘＰｙＯ４－ｘ＋ｃ２２　　　　　（４）
（式中、Ａ、Ｍ、ａ、ｂ、ｘ、およびｙは前記と同じ意味を示すが、式（３）における値とは独立した値をとり、ｃ２２はａ、ｂ、およびＭの価数Ｎに依存する数である。） In the heating step (P24), a silicic acid-boric acid-phosphoric acid compound having a composition represented by the following formula (4) is obtained.
A 2-x-y + a M b Si 1- (x + y) B x P y O 4-x + c22 (4)
(In the formula, A, M, a, b, x, and y have the same meaning as described above, but take an independent value from the value in formula (3), and c22 is the valence of a, b, and M. The number depends on N.)
　式（４）のｃ２２の値は、ａ、ｂ、およびＭの価数Ｎに依存する数であり、例えばａ＝０、ｂ＝１およびＮ＝＋２であればｃ２２＝０であり、一般にはｃ２２＝０．５ａ＋０．５Ｎｂ－１で表される。また、Ｎは+２価であるのが好ましい。 The value of c22 in equation (4) is a number that depends on the valence N of a, b, and M. For example, if a = 0, b = 1, and N = + 2, c22 = 0. c22 = 0.5a + 0.5Nb−1. N is preferably +2 valent.
　加熱工程の生成物は、結晶粒子が好ましく、さらにオリビン型の結晶粒子がより好ましい。本発明における加熱工程は、粉砕物を加熱することから、残留応力の緩和が促進される。また、加熱により結晶核の生成および粒成長を行うことから、降温過程で行うものに比べて、組成、粒径およびその分布の制御が容易である。 The product of the heating step is preferably crystal particles, and more preferably olivine type crystal particles. Since the heating step in the present invention heats the pulverized product, relaxation of residual stress is promoted. In addition, since the formation of crystal nuclei and grain growth are performed by heating, the composition, grain size, and distribution thereof are easier to control than those in the temperature lowering process.
　さらに、粉砕工程で有機化合物および／または炭素粉末を固化物に含ませた場合の加熱工程は、生成物、好ましくは生成物の結晶粒子の表面に、導電材を結合させる工程となりうる。有機化合物は加熱工程で熱分解され、炭化物となって導電材として機能しうる。 Furthermore, the heating step when the organic compound and / or carbon powder is included in the solidified product in the pulverization step can be a step of bonding a conductive material to the surface of the product, preferably the crystal grains of the product. The organic compound is thermally decomposed in the heating process, becomes a carbide, and can function as a conductive material.
　加熱工程における加熱温度は、５００～１，０００℃が好ましい。加熱温度が５００℃以上であると、結晶を生成しやすい。加熱温度が１，０００℃以下であると、粉砕物の融解を防ぐことができる。加熱温度は６００～９００℃がより好ましい。該加熱温度である場合には、適度な結晶性、粒子径、粒度分布等を有する結晶粒子が得られやすく、好ましくはオリビン型の結晶粒子が得られやすくなる。
　粉砕工程を湿式で行った場合には、分散媒を含むまま加熱工程を行った場合、加熱工程は分散媒を除く工程になりうる。 The heating temperature in the heating step is preferably 500 to 1,000 ° C. When the heating temperature is 500 ° C. or higher, crystals are easily generated. When the heating temperature is 1,000 ° C. or less, melting of the pulverized product can be prevented. The heating temperature is more preferably 600 to 900 ° C. When the heating temperature is used, crystal particles having appropriate crystallinity, particle diameter, particle size distribution, and the like are easily obtained, and olivine-type crystal particles are preferably obtained.
When the pulverization process is performed in a wet manner, when the heating process is performed while the dispersion medium is included, the heating process can be a process of removing the dispersion medium.
　加熱工程における加熱は、一気に温度を上げた後に一定温度で保持してもよいし、また多段階に温度を変化させて行ってもよい。加熱温度が高くなると、生成する粒子径が大きくなる傾向があるため、所望の粒子径に応じて加熱温度を設定することが好ましい。また、加熱時間（加熱温度による保持時間）は所望の粒子径を考慮して１～７２時間が好ましい。加熱は、電気、石油、ガス等を熱源とする、ボックス炉、トンネルキルン炉、ローラーハース炉、ロータリーキルン炉、マイクロウェーブ加熱炉等で行うことが好ましい。 The heating in the heating step may be performed at a constant temperature after the temperature is increased at once, or may be performed by changing the temperature in multiple stages. Since the particle diameter to be generated tends to increase as the heating temperature increases, the heating temperature is preferably set according to the desired particle diameter. The heating time (holding time depending on the heating temperature) is preferably 1 to 72 hours in consideration of a desired particle size. Heating is preferably performed in a box furnace, tunnel kiln furnace, roller hearth furnace, rotary kiln furnace, microwave heating furnace, or the like that uses electricity, oil, gas, or the like as a heat source.
　加熱工程は、溶融工程における加熱と同様に、空気中、不活性ガス中または還元ガス中で実施でき、不活性ガス中または還元ガス中で実施することが好ましい。不活性ガス中および還元ガス中の条件は、溶融工程における条件と同じである。加熱工程は不活性ガス中や還元ガス中で減圧（０．９×１０５Ｐａ以下）して実施してもよい。また、加熱炉内に、還元剤（例えばグラファイト）と粉砕物とを入れた容器を装填して加熱を実施した場合には、粉砕物中のＭの還元（例えばＭ３＋からＭ２＋への変化）を促進することができる。 Similar to the heating in the melting step, the heating step can be carried out in air, in an inert gas or in a reducing gas, and is preferably carried out in an inert gas or in a reducing gas. The conditions in the inert gas and the reducing gas are the same as those in the melting step. The heating step may be carried out under reduced pressure (0.9 × 10 5 Pa or less) in an inert gas or a reducing gas. In addition, when heating is performed by charging a container containing a reducing agent (eg, graphite) and pulverized material in a heating furnace, reduction of M in the pulverized material (eg, change from M 3+ to M 2+) . ) Can be promoted.
　本発明において、加熱工程の後は、通常は常温まで冷却する。該冷却における冷却速度は－３０℃／時間～－３００℃／時間が好ましい。冷却速度を該範囲にすることにより、加熱による歪みを除去でき、生成物が結晶体である場合は、結晶構造を保ったまま目的物を得ることができる。また、冷却手段を用いずに冷却ができる。冷却は、放置して常温まで冷却させるのが好ましい。冷却は不活性ガス中または還元ガス中で行うのが好ましい。 In the present invention, after the heating step, it is usually cooled to room temperature. The cooling rate in the cooling is preferably −30 ° C./hour to −300 ° C./hour. By setting the cooling rate within this range, distortion due to heating can be removed, and when the product is a crystal, the target product can be obtained while maintaining the crystal structure. Moreover, it can cool without using a cooling means. The cooling is preferably allowed to cool to room temperature. Cooling is preferably performed in an inert gas or a reducing gas.
＜ケイ酸化合物＞
　本発明の製造方法により得られるケイ酸化合物は、二次電池用正極材料として有用な新規化合物である。 <Silic acid compound>
The silicic acid compound obtained by the production method of the present invention is a novel compound useful as a positive electrode material for secondary batteries.
　本発明におけるケイ酸化合物は、元素Ａの原子数が１．２以上であるため、１．２未満である場合に比べて多電子型になり、二次電池用正極材料に用いたときに単位質量当たりの容量が大きくなる。
　すなわち、本発明におけるケイ酸－ホウ酸化合物は、元素ＡがＬｉである場合、単位（[ＳｉＯ４]＋[ＢＯ４]）四面体中に対し１個超２個以下のＬｉを含む構造を有するケイ酸－ホウ酸化合物であるため、Ｌｉの原子数を１．２以上にすることができる。本発明の製造方法によれば、[ＳｉＯ４]四面体、[ＢＯ４]四面体、[ＬｉＯ４]四面体および[ＭＯ４]四面体が均一に分布するケイ酸－ホウ酸化合物を得ることができる。
　本発明におけるケイ酸－ホウ酸－リン酸化合物は、元素ＡがＬｉである場合、単位（[ＳｉＯ４]＋[ＢＯ４]＋[ＰＯ４]）四面体に対し１個超２個以下のＬｉを含む構造を有するケイ酸－ホウ酸－リン酸化合物を得ることができるため、Ｌｉの原子数を１．２以上にすることができる。本発明の製造方法によれば、[ＳｉＯ４]四面体、[ＢＯ４]四面体、[ＰＯ４]四面体、[ＬｉＯ４]四面体および[ＭＯ４]四面体が均一に分布するケイ酸－ホウ酸－リン酸化合物を得ることができる。 The silicic acid compound in the present invention has a number of atoms of the element A of 1.2 or more, and therefore has a multi-electron type as compared with a case of less than 1.2, and is a unit when used as a positive electrode material for a secondary battery. The capacity per mass increases.
That is, when the element A is Li, the silicic acid-boric acid compound in the present invention has a structure containing more than one and not more than two Li per unit ([SiO 4 ] + [BO 4 ]) tetrahedron. Since this is a silicic acid-boric acid compound, the number of Li atoms can be 1.2 or more. According to the production method of the present invention, a silicic acid-boric acid compound in which [SiO 4 ] tetrahedron, [BO 4 ] tetrahedron, [LiO 4 ] tetrahedron and [MO 4 ] tetrahedron are uniformly distributed can be obtained. Can do.
In the present invention, when the element A is Li, the silicic acid-boric acid-phosphoric acid compound has more than one and not more than two per unit ([SiO 4 ] + [BO 4 ] + [PO 4 ]) tetrahedron. Since a silicic acid-boric acid-phosphoric acid compound having a structure containing Li can be obtained, the number of Li atoms can be 1.2 or more. According to the production method of the present invention, [SiO 4 ] tetrahedron, [BO 4 ] tetrahedron, [PO 4 ] tetrahedron, [LiO 4 ] tetrahedron and [MO 4 ] tetrahedron are uniformly distributed. A boric acid-phosphoric acid compound can be obtained.
　該ケイ酸－ホウ酸化合物またはケイ酸－ホウ酸－リン酸化合物は、オリビン型結晶粒子を含むものであることが好ましい。オリビン型結晶粒子は、多電子型の理論電気容量を発揮する材料である。該結晶粒子としては、一次粒子および二次粒子の双方を含む。生成物中に二次粒子が存在する場合、一次粒子が破壊されない程度の範囲で解砕および粉砕してもよい。
　本発明の製造方法において、有機化合物および炭素粉末からなる群より選ばれる少なくとも１種を添加した場合には、ケイ酸化合物の表面に有機化合物や炭素粉末に由来する炭素からなる導電材を均一にかつ強固に結合させうる。導電材が結合したケイ酸化合物は、そのまま二次電池用正極材料に用いうる。 The silicic acid-boric acid compound or silicic acid-boric acid-phosphoric acid compound preferably contains olivine type crystal particles. The olivine type crystal particle is a material that exhibits a multi-electron type theoretical electric capacity. The crystal particles include both primary particles and secondary particles. When secondary particles are present in the product, they may be crushed and pulverized as long as the primary particles are not destroyed.
In the production method of the present invention, when at least one selected from the group consisting of an organic compound and carbon powder is added, a conductive material composed of carbon derived from the organic compound or carbon powder is uniformly formed on the surface of the silicic acid compound. And can be firmly bonded. The silicic acid compound to which the conductive material is bonded can be used as it is for a positive electrode material for a secondary battery.
　本発明の製造方法で製造されるケイ酸－ホウ酸化合物の組成は、ＡがＬｉであり、ＭがＦｅおよびＭｎからなる群より選ばれる少なくとも１種を使用した組成である、式（５）で表される化合物が好ましい。ｍは０＜ｍ＜１が特に好ましい。
　Ｌｉ２－ｘ＋ａ（ＦｅｍＭｎ１－ｍ）ｂＳｉ１－ｘＢｘＯ４－ｘ＋ｃ１２　　（５）
（式中の記号は前記と同じ意味を示し、ｍは０≦ｍ≦１である。）
　式（５）の組成のケイ酸－ホウ酸化合物を得るために、溶融工程において式（５Ａ）で表される組成を有する溶融物を得ることが好ましい。
　Ｌｉ２－ｘ＋ａ（ＦｅｍＭｎ１－ｍ）ｂＳｉ１－ｘＢｘＯ４－ｘ＋ｃ１１　　（５Ａ）
（式中の記号は前記と同じ意味を示し、ｍは０≦ｍ≦１である。ただし、式（５Ａ）と式（５）において、ａ、ｂ、ｘ、およびｍは独立した値を示す。） The composition of the silicic acid-boric acid compound produced by the production method of the present invention is a composition in which A is Li and M is at least one selected from the group consisting of Fe and Mn. The compound represented by these is preferable. m is particularly preferably 0 <m <1.
Li 2-x + a (Fe m Mn 1-m ) b Si 1-x B x O 4-x + c12 (5)
(The symbols in the formula have the same meaning as described above, and m is 0 ≦ m ≦ 1.)
In order to obtain the silicic acid-boric acid compound having the composition of the formula (5), it is preferable to obtain a melt having the composition represented by the formula (5A) in the melting step.
Li 2-x + a (Fe m Mn 1-m) b Si 1-x B x O 4-x + c11 (5A)
(The symbols in the formula have the same meaning as described above, and m is 0 ≦ m ≦ 1. However, in formula (5A) and formula (5), a, b, x, and m represent independent values. .)
　また、本発明の製造方法で製造されるケイ酸－ホウ酸－リン酸化合物の組成は、ＡがＬｉであり、ＭがＦｅおよびＭｎからなる群より選ばれる少なくとも１種を使用した組成である、式（６）で表される化合物が好ましい。ｍは０＜ｍ＜１が特に好ましい。
　Ｌｉ２－ｘ－ｙ＋ａ（ＦｅｍＭｎ１－ｍ）ｂＳｉ１－（ｘ＋ｙ）ＢｘＰｙＯ４－ｘ＋ｃ２２　（６）
（式中の記号は前記と同じ意味を示し、ｍは０≦ｍ≦１である。）
　式（６）の組成のケイ酸－ホウ酸－リン酸化合物を得るためは、溶融工程において式（６Ａ）で表される組成を有する溶融物を得ることが好ましい。
　Ｌｉ２－ｘ－ｙ＋ａ（ＦｅｍＭｎ１－ｍ）ｂＳｉ１－（ｘ＋ｙ）ＢｘＰｙＯ４－ｘ＋ｃ２１　　　　（６Ａ）
（式中の記号は前記と同じ意味を示し、ｍは０≦ｍ≦１である。ただし、式（６Ａ）と式（６）において、ａ、ｂ、ｘ、ｙ、およびｍは独立した値を示す。） The composition of the silicic acid-boric acid-phosphoric acid compound produced by the production method of the present invention is a composition using at least one selected from the group consisting of A being Li and M being Fe and Mn. The compound represented by Formula (6) is preferable. m is particularly preferably 0 <m <1.
Li 2-x-y + a (Fe m Mn 1-m) b Si 1- (x + y) B x P y O 4-x + c22 (6)
(The symbols in the formula have the same meaning as described above, and m is 0 ≦ m ≦ 1.)
In order to obtain the silicic acid-boric acid-phosphoric acid compound having the composition of formula (6), it is preferable to obtain a melt having the composition represented by formula (6A) in the melting step.
Li 2-x-y + a (Fe m Mn 1-m) b Si 1- (x + y) B x P y O 4-x + c21 (6A)
(The symbols in the formula have the same meaning as described above, and m is 0 ≦ m ≦ 1. However, in formula (6A) and formula (6), a, b, x, y, and m are independent values. Is shown.)
　式（２）で表される組成を有するケイ酸－ホウ酸化合物が結晶である場合、固溶体結晶または共晶であるのが好ましい。
　このうち、式（２）中、ｘが０＜ｘ≦０．２である場合には、固溶体結晶になりやすい。その理由は、式（７）で表される式によって、Ｓｉの一部がＢで置換されるためと考えられる。
（１－ｘ）Ａ２ＭＳｉＯ４　＋　ｘＡＭＢＯ３　→　Ａ２－ｘＭ[Ｓｉ１－ｘＢｘ]Ｏ４－ｘ　　　　　（７）
（式中、ｘは０＜ｘ≦０．２であり、[　]は固溶体であることを表す。）
　該固溶体結晶は、Ｓｉのみからなる結晶に比べ、結晶構造が疎になり、Ｌｉイオンが結晶内で移動しやすくなる。よって高い容量が得られ、かつ電気伝導度が上昇するため、二次電池用正極材料に用いた場合に充放電のサイクル性が向上しうる。 When the silicic acid-boric acid compound having the composition represented by the formula (2) is a crystal, it is preferably a solid solution crystal or a eutectic crystal.
Among these, in the formula (2), when x is 0 <x ≦ 0.2, a solid solution crystal is likely to be formed. The reason is considered that a part of Si is substituted with B by the formula represented by formula (7).
(1-x) A 2 MSiO 4 + xAMBO 3 → A 2-x M [Si 1-x B x ] O 4-x (7)
(In the formula, x represents 0 <x ≦ 0.2, and [] represents a solid solution.)
The solid solution crystal has a sparse crystal structure and a Li ion easily moves in the crystal as compared with a crystal made of only Si. Therefore, a high capacity can be obtained and the electrical conductivity can be increased. Therefore, when used as a positive electrode material for a secondary battery, charge / discharge cycleability can be improved.
　本発明におけるケイ酸－ホウ酸化合物は、固溶体結晶のケイ酸－ホウ酸化合物を含む場合は、Ｓｉの一部をＢで置換した固溶体結晶であるオリビン型結晶粒子を含むケイ酸－ホウ酸化合物であるのが好ましい。
　ケイ酸－ホウ酸化合物が、固溶体結晶であると、二次電池用正極材料に用いた場合に、Ｌｉイオンが結晶内で移動しやすくなるために高容量になり、かつ、電気伝導度が上昇する。よって、二次電池用正極材料に使用する場合には、理論容量が得られやすく、充放電のサイクル性が向上すると考えられる。 When the silicic acid-boric acid compound in the present invention contains a silicic acid-boric acid compound in solid solution crystal, the silicic acid-boric acid compound contains olivine type crystal particles which are solid solution crystals in which a part of Si is substituted with B. Is preferred.
When the silicic acid-boric acid compound is a solid solution crystal, when it is used as a positive electrode material for a secondary battery, Li ions easily move in the crystal, resulting in high capacity and increased electrical conductivity. To do. Therefore, when used as a positive electrode material for a secondary battery, a theoretical capacity is easily obtained, and it is considered that the charge / discharge cycleability is improved.
　また、式（２）中、ｘが０．２＜ｘ≦０．７である場合には、共晶になりやすい。０．２＜ｘ＜０．７であることが好ましい。共晶であるケイ酸－ホウ酸化合物（以下、「ケイ酸－ホウ酸化合物の共晶体」、または単に「共晶体」という。）とは、ケイ素原子を含む結晶と、ホウ原子を含む結晶と、ホウ素原子およびケイ素原子を含む結晶が、共存している結晶体、をいう。本発明においては、
　Ａ２－ｚＭＳｉ１－ｚＢｚＯ４（ｚは０．２＜ｚ＜０．８である。）のオリビン型結晶とともに、Ａ２ＭＳｉＯ４のオリビン型結晶およびＡＭＢＯ３のオリビン型結晶からなる群より選ばれる少なくとも１種とを含む共晶体が好ましい。
　該共晶体は、下式（８）で表される反応メカニズムにより生成すると考えられる。
（１－ｘ）Ａ２ＭＳｉＯ４　＋　ｘＡＭＢＯ３　→　（１－ｘ－ｗ１）Ａ２ＭＳｉＯ４　＋　（ｘ－ｗ２）ＡＭＢＯ３　＋　ｗＡ２－ｚＭＳｉ１－ｚＢｚＯ４－ｚ　（８）
（式中、Ａ、Ｍは前記と同じ意味を示し、ｘおよびｚは、０．２＜ｘ≦０．７および０．２＜ｚ＜０．８であり、ｗ１、ｗ２、ｗはそれぞれ０～１の数であり、かつ、ｗ１＋ｗ２＝ｗである。）
　本発明のケイ酸－ホウ酸化合物が共晶体であると、電気伝導度が上昇する傾向があり好ましい。その理由は、複数の結晶構造を有し、電気導電度が異なる結晶子が生成することにより、電位が負荷されたときに結晶子間に電位差が生じることから、一次粒子自体の電気伝導度が上昇するため、と考えられる。また、一次粒子内の各結晶子間に、粒界を有する構造をなし、この粒界は一次粒子内に比べ極めて薄いので、一次粒子自体の電気伝導度が上昇するためとも考えられる。
　本発明のケイ酸－ホウ酸化合物としては、高い電気伝導度を得やすく、充放電サイクル性が向上するため、共晶体であるのが特に好ましい。 Further, in the formula (2), when x is 0.2 <x ≦ 0.7, eutectic is likely to occur. It is preferable that 0.2 <x <0.7. The eutectic silicic acid-boric acid compound (hereinafter referred to as “silicic acid-boric acid compound eutectic”, or simply “eutectic”) includes a crystal containing a silicon atom, a crystal containing a boron atom, , A crystal in which crystals containing boron atoms and silicon atoms coexist. In the present invention,
From the olivine type crystal of A 2 MSiO 4 and the olivine type crystal of AMBO 3 together with the olivine type crystal of A 2−z MSi 1−z B z O 4 (z is 0.2 <z <0.8). A eutectic containing at least one selected from the group consisting of
The eutectic is considered to be produced by the reaction mechanism represented by the following formula (8).
(1-x) A 2 MSiO 4 + xAMBO 3 → (1-xw 1 ) A 2 MSiO 4 + (xw 2 ) AMBO 3 + wA 2-z MSi 1-z B z O 4-z ( 8)
(In the formula, A and M have the same meaning as described above, x and z are 0.2 <x ≦ 0.7 and 0.2 <z <0.8, and w 1 , w 2 and w are Each is a number between 0 and 1 and w 1 + w 2 = w.)
The silicic acid-boric acid compound of the present invention is preferably a eutectic because the electric conductivity tends to increase. The reason is that, due to the generation of crystallites having a plurality of crystal structures and different electrical conductivities, a potential difference is generated between the crystallites when a potential is applied. This is thought to be due to the rise. In addition, a structure having a grain boundary is formed between the crystallites in the primary particle, and this grain boundary is extremely thin as compared with the inside of the primary particle, which is considered to be because the electrical conductivity of the primary particle itself is increased.
The silicic acid-boric acid compound of the present invention is particularly preferably an eutectic because it easily obtains high electrical conductivity and improves charge / discharge cycleability.
　本発明のケイ酸－ホウ酸化合物は、ケイ酸－ホウ酸化合物を二次電池用正極に適用した場合に高い容量を有し、良好なサイクル特性を得やすいという点からは、固溶体結晶が特に好ましく、二次電池用正極に適用した場合に高い電気伝導度を得やすいという点からは、共晶が特に好ましい。 The silicic acid-boric acid compound of the present invention has a high capacity when the silicic acid-boric acid compound is applied to a positive electrode for a secondary battery, and solid solution crystals are particularly preferable in that good cycle characteristics are easily obtained. Preferably, eutectic is particularly preferable from the viewpoint that high electrical conductivity is easily obtained when applied to a positive electrode for a secondary battery.
　式（４）で表される組成を有するケイ酸－ホウ酸－リン酸化合物が結晶である場合、固溶体結晶または共晶であるのが好ましい。
　このうち、式（４）中、ｘおよびｙが、０＜（ｘ＋ｙ）≦０．２である場合には、固溶体結晶になりやすい。その理由は、式（９）で表される式によって、Ｓｉの一部がＢおよびＰで置換されるためと考えられる。
（１－ｘ－ｙ）Ａ２ＭＳｉＯ４　＋　ｘＡＭＰＯ４　＋　ｙＡＭＢＯ３　
→　Ａ２－ｘ－ｙＭ[Ｓｉ１－ｘ－ｙＰｘＢｙ]Ｏ４－ｙ　　　　　　（９）
（式中、ｘおよびｙは０＜（ｘ＋ｙ）≦０．２を満たし、[　]は固溶体であることを表す。）
　該固溶体結晶は、Ｓｉのみからなる結晶に比べ、結晶構造が疎になり、Ｌｉイオンが結晶内で移動しやすくなる。よって高い容量が得られ、かつ電気伝導度が上昇するため、二次電池用正極材料に用いた場合に充放電のサイクル性が向上しうる。また、特に式（４）中、ａがａ＝０、ｘ＝ｙであると、ＰおよびＢの平均価電数が＋４となり、Ｓｉの価電数と等しくなり、化学量論比および電気的中性が維持され、構造の歪みがなくなり、充放電のサイクル特性が向上すると考えられる。 When the silicic acid-boric acid-phosphoric acid compound having the composition represented by the formula (4) is a crystal, it is preferably a solid solution crystal or a eutectic crystal.
Among these, in Formula (4), when x and y are 0 <(x + y) ≦ 0.2, a solid solution crystal is likely to be formed. The reason is considered that a part of Si is replaced by B and P by the formula represented by formula (9).
(1-xy) A 2 MSiO 4 + xAMPO 4 + yAMBO 3
→ A 2-x-y M [Si 1-x-y P x B y] O 4-y (9)
(In the formula, x and y satisfy 0 <(x + y) ≦ 0.2, and [] represents a solid solution.)
The solid solution crystal has a sparse crystal structure and a Li ion easily moves in the crystal as compared with a crystal made of only Si. Therefore, a high capacity can be obtained and the electrical conductivity can be increased. Therefore, when used as a positive electrode material for a secondary battery, charge / discharge cycleability can be improved. In particular, in formula (4), when a is a = 0 and x = y, the average valence number of P and B is +4, which is equal to the valence number of Si, and the stoichiometric ratio and electrical It is considered that neutrality is maintained, structural distortion is eliminated, and cycle characteristics of charge / discharge are improved.
　本発明におけるケイ酸－ホウ酸－リン酸化合物は、固溶体結晶のケイ酸－ホウ酸－リン酸化合物を含む場合は、Ｓｉの一部をＢおよびＰで置換した固溶体結晶であるオリビン型結晶粒子を含むケイ酸－ホウ酸－リン酸化合物であるのが好ましい。
　ケイ酸－ホウ酸－リン酸化合物が、固溶体結晶であると、二次電池用正極材料に用いた場合に、Ｌｉイオンが結晶内で移動しやすくなるために高容量になり、かつ、電気伝導度が上昇する。よって、二次電池用正極材料に使用する場合には、理論容量が得られやすく、充放電のサイクル性が向上すると考えられる。 When the silicic acid-boric acid-phosphoric acid compound in the present invention contains a solid solution crystalline silicic acid-boric acid-phosphoric acid compound, olivine type crystal particles which are solid solution crystals in which a part of Si is substituted with B and P A silicic acid-boric acid-phosphoric acid compound containing
When the silicic acid-boric acid-phosphoric acid compound is a solid solution crystal, when it is used as a positive electrode material for a secondary battery, Li ions easily move in the crystal, resulting in a high capacity and electrical conductivity. The degree rises. Therefore, when used as a positive electrode material for a secondary battery, a theoretical capacity is easily obtained, and it is considered that the charge / discharge cycleability is improved.
　また、式（４）中、ｘおよびｙが０．２＜（ｘ＋ｙ）≦０．７である場合には、共晶になりやすい。０．２＜（ｘ＋ｙ）＜０．７であることが好ましい。共晶であるケイ酸－ホウ酸－リン酸化合物（以下、「ケイ酸－ホウ酸－リン酸化合物の共晶体」、または単に「共晶体」という。）とは、ケイ素原子を含む結晶と、ホウ素原子を含む結晶と、リン原子を含む結晶と、リン原子とホウ素原子とケイ素原子とを含む結晶が、共存している結晶体、をいう。本発明においては、Ａ２－ｐ－ｑＭｂＳｉ１－ｐ－ｑＰｐＢｑＯ４－ｑ（ａおよびｂは前記と同じ意味を示し、ｐは０．２＜ｐ＜０．８であり、ｑは０．２＜ｑ＜０．８であり、ｐ＋ｑは０．２＜ｐ＋ｑ＜０．８である。）で表される組成を有するオリビン型結晶とともに、Ａ２ＭＳｉＯ４のオリビン型結晶、ＡＭＢＯ３のオリビン型結晶およびＡＭＰＯ４のオリビン型結晶からなる群より選ばれる少なくとも１種とを含む共晶体が好ましい。
　ケイ酸－ホウ酸－リン酸化合物は、下式（１０）で表される反応メカニズムにより生成すると考えられる。
　（１－ｘ－ｙ）Ａ２ＭＳｉＯ４　＋　ｘＡＭＢＯ４　＋　ｙＡＭＰＯ４　→　（１－ｘ－ｙ－ｗ１）Ａ２ＭＳｉＯ４　＋　（ｘ－ｗ２）ＡＭＢＯ３　＋　（ｙ－ｗ３）ＡＭＰＯ４　＋　（ｘ＋ｙ－ｗ４）ＬｉＭ（Ｂ，Ｐ）Ｏｒ　＋　ｗ５Ａ２－ｐ－ｑＭｂＳｉ１－ｐ－ｑＰｐＢｑＯ４－ｑ　　　　　（１０）
（式中、Ａ、Ｍは前記と同じ意味を示し、ｘ、ｙ、およびｘ＋ｙは、０．２＜ｘ≦０．７、０．２＜ｙ≦０．７、および０．２＜ｘ＋ｙ≦０．７であり、ｐ、ｑおよびｐ＋ｑは、０．２＜ｐ＜０．８、０．２＜ｑ＜０．８、および０．２＜（ｐ＋ｑ）＜０．８であり、ｗ１～ｗ５はそれぞれ０～１の数であり、かつ、ｗ１＋ｗ２＋ｗ３＋ｗ４＋ｗ５＝１である。）
　本発明のケイ酸－ホウ酸－リン酸化合物が共晶体であると好ましい理由は、ケイ酸－ホウ酸化合物と同様である。
　本発明のケイ酸－ホウ酸－リン酸化合物としては、高い電気伝導度を得やすく、充放電サイクル性が向上するため、共晶体であるのが特に好ましい Further, in the formula (4), when x and y are 0.2 <(x + y) ≦ 0.7, eutectic is likely to occur. It is preferable that 0.2 <(x + y) <0.7. The eutectic silicic acid-boric acid-phosphoric acid compound (hereinafter referred to as “silicic acid-boric acid-phosphoric acid compound eutectic”, or simply “eutectic”) includes a crystal containing a silicon atom, A crystal containing a boron atom, a crystal containing a phosphorus atom, and a crystal containing a phosphorus atom, a boron atom, and a silicon atom coexist. In the present invention, A 2-p-q M b Si 1-p-q P p B q O 4-q (a and b are as defined above, p is 0.2 <p <0.8 And q is 0.2 <q <0.8, and p + q is 0.2 <p + q <0.8.) And an olivine of A 2 MSiO 4 A eutectic containing at least one selected from the group consisting of a type crystal, an olivine type crystal of AMBO 3 and an olivine type crystal of AMPO 4 is preferable.
The silicic acid-boric acid-phosphoric acid compound is considered to be produced by the reaction mechanism represented by the following formula (10).
(1-xy) A 2 MSiO 4 + xAMBO 4 + yAMPO 4 → (1-xy-w 1 ) A 2 MSiO 4 + (xw 2 ) AMBO 3 + (yw 3 ) AMPO 4 + (x + y-w 4 ) LiM (B, P) O r + w 5 A 2-p-q M b Si 1-p-q P p B q O 4-q (10)
(In the formula, A and M have the same meaning as described above, and x, y, and x + y are 0.2 <x ≦ 0.7, 0.2 <y ≦ 0.7, and 0.2 <x + y ≦, respectively. 0.7, p, q, and p + q are 0.2 <p <0.8, 0.2 <q <0.8, and 0.2 <(p + q) <0.8, and w 1 ˜w 5 is a number from 0 to 1, respectively, and w 1 + w 2 + w 3 + w 4 + w 5 = 1.)
The reason why the silicic acid-boric acid-phosphoric acid compound of the present invention is preferably an eutectic is the same as that of the silicic acid-boric acid compound.
The silicic acid-boric acid-phosphoric acid compound of the present invention is particularly preferably an eutectic because it is easy to obtain high electrical conductivity and charge / discharge cycleability is improved.
　本発明のケイ酸－ホウ酸－リン酸化合物の製造方法においては、ケイ酸－ホウ酸－リン酸化合物を二次電池用正極に適用した場合に高い容量を有し、良好なサイクル特性を得やすいという点からは、固溶体結晶が特に好ましく、二次電池用正極に適用した場合に高い電気伝導度を得やすいという点からは、共晶が特に好ましい。 In the method for producing a silicic acid-boric acid-phosphoric acid compound of the present invention, when the silicic acid-boric acid-phosphoric acid compound is applied to a positive electrode for a secondary battery, it has a high capacity and obtains good cycle characteristics. A solid solution crystal is particularly preferable from the viewpoint of easiness, and a eutectic is particularly preferable from the viewpoint that high electrical conductivity is easily obtained when applied to a positive electrode for a secondary battery.
　本発明のケイ酸化合物の平均粒径は、体積換算のメディアン径で１０ｎｍ～１０μｍの平均粒径が好ましく、１０ｎｍ～６μｍがより好ましく、１０ｎｍ～２μｍが特に好ましい。下限の値は１００ｎｍであってもよい。平均粒径を該範囲とすることにより、より導電性が高くなる。平均粒径は、例えば電子顕微鏡による観察やレーザ回折式粒度分布計による測定等によって求められる。
　ケイ酸化合物の比表面積は、０．２～２００ｍ２／ｇが好ましく、０．５～２００ｍ２／ｇが好ましく、１～２００ｍ２／ｇが特に好ましい。上限の値は１００ｍ２／ｇであってもよく１０ｍ２／ｇであってもよい。比表面積を該範囲とすることにより、導電性が高くなる。比表面積は、例えば窒素吸着法による比表面積測定装置で測定できる。 The average particle diameter of the silicate compound of the present invention is preferably an average particle diameter of 10 nm to 10 μm, more preferably 10 nm to 6 μm, and particularly preferably 10 nm to 2 μm in terms of volume median diameter. The lower limit value may be 100 nm. By making the average particle diameter within this range, the conductivity becomes higher. The average particle diameter can be determined by, for example, observation with an electron microscope or measurement with a laser diffraction particle size distribution meter.
The specific surface area of the silicate compound is preferably 0.2 ~ 200m 2 / g, preferably 0.5 ~ 200m 2 / g, 1 ~ 200m 2 / g is particularly preferred. The upper limit value may be 100 m 2 / g or 10 m 2 / g. By setting the specific surface area within this range, the conductivity is increased. The specific surface area can be measured by, for example, a specific surface area measuring apparatus using a nitrogen adsorption method.
＜二次電池用正極および二次電池の製造方法＞
　本発明のケイ酸化合物の製造方法によって得られたケイ酸化合物は、二次電池用正極材料として有用である。よって、該ケイ酸化合物を用いて、二次電池用正極および二次電池を製造できる。
　二次電池としては、金属リチウム二次電池、リチウムイオン二次電池、リチウムポリマー二次電池等が挙げられるが、リチウムイオン二次電池が好ましい。電池形状は制限されることはなく、例えば円筒状、角型、コイン型等、種々の形状、サイズを適宜採用することができる。 <Positive electrode for secondary battery and method for producing secondary battery>
The silicic acid compound obtained by the method for producing a silicic acid compound of the present invention is useful as a positive electrode material for a secondary battery. Therefore, the positive electrode for secondary batteries and a secondary battery can be manufactured using this silicate compound.
Examples of the secondary battery include a metal lithium secondary battery, a lithium ion secondary battery, and a lithium polymer secondary battery, and a lithium ion secondary battery is preferable. The battery shape is not limited, and various shapes and sizes such as a cylindrical shape, a square shape, and a coin shape can be appropriately employed.
　二次電池用正極の製造は、本発明の製造方法で得られるケイ酸化合物を用いるほかは公知の電極の製造方法に従えばよい。例えば、本発明のケイ酸化合物を必要に応じて公知の結着材（ポリテトラフルオロエチレン、ポリビニリデンフルオライド、ポリビニルクロライド、エチレンプロピレンジエンポリマー、スチレン－ブタジエンゴム、アクリロニトリル－ブタジエンゴム、フッ素ゴム、ポリ酢酸ビニル、ポリメチルメタクリレート、ポリエチレン、ニトロセルロース等）、さらに必要に応じて公知の導電材（アセチレンブラック、カーボン、グラファイト、天然黒鉛、人造黒鉛、ニードルコークス等）と混合した後、得られた混合粉末をステンレス鋼製等の支持体上に圧着成形したり、金属製容器に充填すればよい。あるいは、例えば、該混合粉末を有機溶剤（Ｎ－メチルピロリドン、トルエン、シクロヘキサン、ジメチルホルムアミド、ジメチルアセトアミド、メチルエチルケトン、酢酸メチル、アクリル酸メチル、ジエチルトリアミン、Ｎ－Ｎ－ジメチルアミノプロピルアミン、エチレンオキシド、テトラヒドロフラン等）と混合して得られたスラリーをアルミニウム、ニッケル、ステンレス、銅等の金属基板上に塗布する等の方法によっても電極を製造できる。 The production of the positive electrode for the secondary battery may be performed in accordance with a known electrode production method, except that the silicate compound obtained by the production method of the present invention is used. For example, if necessary, the silicic acid compound of the present invention is added to a known binder (polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl chloride, ethylene propylene diene polymer, styrene-butadiene rubber, acrylonitrile-butadiene rubber, fluororubber, Obtained by mixing with polyvinyl acetate, polymethyl methacrylate, polyethylene, nitrocellulose, etc.) and, if necessary, known conductive materials (acetylene black, carbon, graphite, natural graphite, artificial graphite, needle coke, etc.). The mixed powder may be pressure-formed on a support made of stainless steel or filled in a metal container. Alternatively, for example, the mixed powder is mixed with an organic solvent (N-methylpyrrolidone, toluene, cyclohexane, dimethylformamide, dimethylacetamide, methyl ethyl ketone, methyl acetate, methyl acrylate, diethyltriamine, NN-dimethylaminopropylamine, ethylene oxide, tetrahydrofuran. The electrode can also be produced by a method such as applying a slurry obtained by mixing with a metal substrate such as aluminum, nickel, stainless steel or copper.
　二次電池の製造は、本発明の製造方法で得られる二次電池用正極を電極として用いる以外は、公知の二次電池における構成要素を採用することができる。セパレータ、電池ケース等の要素についても同様である。負極としては、活物質として公知の負極用活物質を使用することが可能であるが、炭素材料、アルカリ金属材料およびアルカリ土類金属材料からなる群から選ばれる少なくとも１種を用いることが好ましい。電解液としては、非水系が好ましい。すなわち、本発明の製造方法で得られる二次電池としては、非水電解質リチウムイオン二次電池が好ましい。 For the production of the secondary battery, components in a known secondary battery can be adopted except that the positive electrode for a secondary battery obtained by the production method of the present invention is used as an electrode. The same applies to elements such as a separator and a battery case. As the negative electrode, a known negative electrode active material can be used as the active material, but it is preferable to use at least one selected from the group consisting of a carbon material, an alkali metal material, and an alkaline earth metal material. The electrolyte solution is preferably non-aqueous. That is, as the secondary battery obtained by the production method of the present invention, a nonaqueous electrolyte lithium ion secondary battery is preferable.
　本発明を、実施例を挙げて具体的に説明するが、本発明は以下の説明に限定されない。
［実施例１～１７］
（溶融工程）
　溶融物の組成がＬｉ２Ｏ、Ｎａ２Ｏ、ＦｅＯ、ＭｎＯ、ＣｏＯ、ＮｉＯ、ＳｉＯ２、Ｂ２Ｏ３換算量（単位：モル％）で、それぞれ表１に示す割合となるように、炭酸リチウム（Ｌｉ２ＣＯ３）、炭酸ナトリウム（Ｎａ２ＣＯ３）、四酸化三鉄（Ｆｅ３Ｏ４）、二酸化マンガン（ＭｎＯ２）、四酸化三コバルト（Ｃｏ３Ｏ４）、酸化ニッケル（ＮｉＯ）、二酸化ケイ素（ＳｉＯ２）、および酸化ホウ素（Ｂ２Ｏ３）を秤量し、乾式で混合・粉砕して、原料調合物を得た。 The present invention will be specifically described with reference to examples, but the present invention is not limited to the following description.
[Examples 1 to 17]
(Melting process)
Carbonic acid so that the composition of the melt is Li 2 O, Na 2 O, FeO, MnO, CoO, NiO, SiO 2 , B 2 O 3 equivalent (unit: mol%) and the ratio shown in Table 1 respectively. Lithium (Li 2 CO 3 ), sodium carbonate (Na 2 CO 3 ), triiron tetroxide (Fe 3 O 4 ), manganese dioxide (MnO 2 ), tricobalt tetroxide (Co 3 O 4 ), nickel oxide (NiO ), Silicon dioxide (SiO 2 ), and boron oxide (B 2 O 3 ) were weighed, mixed and pulverized by a dry method to obtain a raw material formulation.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　各原料調合物を、ロジウムを２０質量％含む白金合金製のるつぼにそれぞれ充填した。次に、るつぼをケイ化モリブデン製の発熱体を備える電気炉（モトヤマ社製、装置名：ＮＨ－３０３５）の中に入れた。該電気炉内を２Ｌ／分でＮ２ガスを流通しつつ、＋３００℃／時間の速度で昇温し、１，４００～１，５００℃で０．５時間加熱した。目視で透明になったことを確認して、それぞれの溶融物を得た。得られた溶融物の組成式を表１の右欄に示す。 Each raw material formulation was filled in a platinum alloy crucible containing 20% by mass of rhodium. Next, the crucible was placed in an electric furnace (manufactured by Motoyama, apparatus name: NH-3035) equipped with a heating element made of molybdenum silicide. While flowing N 2 gas at a rate of 2 L / min in the electric furnace, the temperature was raised at a rate of + 300 ° C./hour and heated at 1,400 to 1,500 ° C. for 0.5 hour. Each melt was obtained after confirming that it became transparent visually. The composition formula of the obtained melt is shown in the right column of Table 1.
（冷却工程）
　溶融工程で得たるつぼ中の溶融物を、毎分４００回転で回転する直径約１５ｃｍの双ローラを通すことにより、－１×１０５ ℃／秒で冷却し、フレーク状の固化物を得た。 (Cooling process)
The melt in the crucible obtained in the melting step was cooled at −1 × 10 5 ° C./second by passing through a twin roller having a diameter of about 15 cm rotating at 400 revolutions per minute to obtain a flaky solidified product. .
（粉砕工程）
　冷却工程で得たフレーク状固化物を軽く手で揉んで細かくした後、乳棒と乳鉢とを用いて粗粉砕した。さらに、粉砕媒体としてジルコニア製ボールを用いた遊星ミルで、粗粉砕後の固化物を乾式で粉砕して粉砕物を得た。実施例１および４の粉砕物をレーザ回折／散乱式粒度分析計（堀場製作所製、装置名：ＬＡ－９５０）を用いて粒子径を測定したところ、体積換算のメディアン径は２．０μｍ（実施例１）および２．１μｍ（実施例４）であった。 (Crushing process)
The flake solidified product obtained in the cooling step was lightly kneaded and finely ground, and then coarsely pulverized using a pestle and mortar. Further, the coarsely pulverized solidified product was pulverized in a dry manner using a planetary mill using zirconia balls as a pulverizing medium to obtain a pulverized product. When the particle size of the pulverized product of Examples 1 and 4 was measured using a laser diffraction / scattering particle size analyzer (manufactured by Horiba, Ltd., apparatus name: LA-950), the volume-converted median diameter was 2.0 μm (implemented) Example 1) and 2.1 μm (Example 4).
（加熱工程）
　粉砕工程で得た粉砕物を３体積％Ｈ２－Ａｒ雰囲気におき、それぞれの実施例について、６００℃、７００℃、８００℃、および９００℃の４種類の温度条件で８時間加熱し、次に－２００℃／時間の速度で冷却（空冷）し、ケイ酸－ホウ酸化合物粒子を析出させた。各実施例のうち、加熱工程を７００℃で実施して得た粒子について、Ｘ線回折、粒度分布、組成分析を行った。 (Heating process)
The pulverized product obtained in the pulverization step was placed in a 3% by volume H 2 —Ar atmosphere, and each example was heated for 8 hours at four temperature conditions of 600 ° C., 700 ° C., 800 ° C., and 900 ° C. The mixture was cooled (air cooled) at a rate of -200 ° C./hour to precipitate silicic acid-boric acid compound particles. Among the examples, X-ray diffraction, particle size distribution, and composition analysis were performed on particles obtained by carrying out the heating step at 700 ° C.
（Ｘ線回折）
　得られたケイ酸－ホウ酸化合物粒子の鉱物相を、Ｘ線回折装置（リガク社製、装置名：ＲＩＮＴ　ＴＴＲIII）を用いて測定した。
　実施例１～４、実施例８～１７で得た粒子は、いずれも斜方晶のオリビン型Ｌｉ２ＭＳｉＯ４（Ｋ．Ｚａｇｈｉｂ　ｅｔ　ａｌ．，　Ｊｏｕｒｎａｌ　ｏｆ　Ｐｏｗｅｒ　Ｓｏｕｒｃｅｓ，　１６０，　１３８１－１３８６，　２００６　および　Ｒ．Ｄｏｍｉｎｋｏ　ｅｔ　ａｌ．，　Ｅｌｅｃｔｒｏｃｈｅｍｉｓｔｒｙ　Ｃｏｍｍｕｎｉｃａｔｉｏｎｓ，　８，　２１７－２２２　（２００６）参照）に類似した回折パターンを示した。該結果から、ケイ酸－ホウ酸化合物粒子が結晶であり、かつ、Ｌｉ２ＭＳｉＯ４結晶のＳｉの一部がＢに置換された固溶体結晶からなることが確認できた。
　また、実施例５～７においては、Ｌｉ２ＭＳｉＯ４、ＬｉＭＢＯ３、及びこれらの固溶体を含む共晶と考えられる回折パターンを示した。該結果から、ｘが０．２＜ｘ≦０．７である場合には、Ｌｉ２ＭＳｉＯ４、ＬｉＭＢＯ３、およびこれらの固溶体を含む共晶が得られることが確認できた。
　実施例１、２、３、および４で得た各結晶のＸ線回折パターンを、それぞれ図１の（ａ）、（ｂ）、（ｃ）、（ｄ）に、実施例５、６、および７で得た各結晶のＸ線回折パターンを、それぞれ図２の（ａ）、（ｂ）、（ｃ）に、実施例８、９、および１０で得た各結晶のＸ線回折パターンを、それぞれ図３の（ａ）、（ｂ）、（ｃ）に、示す。 (X-ray diffraction)
The mineral phase of the obtained silicic acid-boric acid compound particles was measured using an X-ray diffraction apparatus (manufactured by Rigaku Corporation, apparatus name: RINT TTRIII).
The particles obtained in Examples 1 to 4 and Examples 8 to 17 are all orthorhombic olivine type Li 2 MSiO 4 (K. Zaghib et al., Journal of Power Sources, 160, 1381-1386, 2006 and R. Dominko et al., Electrochemistry Communications, 8, 217-222 (2006)). From the results, it was confirmed that the silicic acid-boric acid compound particles were crystals and a solid solution crystal in which a part of Si in the Li 2 MSiO 4 crystal was substituted with B.
In Examples 5 to 7, diffraction patterns considered to be eutectics containing Li 2 MSiO 4 , LiMBO 3 , and solid solutions thereof were shown. From the results, it was confirmed that when x is 0.2 <x ≦ 0.7, a eutectic containing Li 2 MSiO 4 , LiMBO 3 , and a solid solution thereof can be obtained.
The X-ray diffraction patterns of the crystals obtained in Examples 1, 2, 3, and 4 are respectively shown in (a), (b), (c), and (d) of FIG. The X-ray diffraction patterns of the crystals obtained in Example 7 are shown in FIGS. 2 (a), (b), and (c), respectively. These are shown in FIGS. 3A, 3B, and 3C, respectively.
（粒度分布）
　実施例２および９で得たケイ酸－ホウ酸化合物の粒径分布をレーザ回折／散乱式粒度分布測定装置（堀場製作所製、装置名：ＬＡ－９２０）で測定した。体積換算のメディアン径はそれぞれ２．５μｍ（実施例２）および２．８μｍ（実施例９）であった。さらに、ケイ酸－ホウ酸化合物の比表面積を比表面積測定装置（島津製作所製、装置名：ＡＳＡＰ２０２０）で測定したところ、いずれも１．２ｍ２／ｇであった。 (Particle size distribution)
The particle size distribution of the silicic acid-boric acid compound obtained in Examples 2 and 9 was measured with a laser diffraction / scattering particle size distribution analyzer (manufactured by Horiba, Ltd., apparatus name: LA-920). The volume-converted median diameters were 2.5 μm (Example 2) and 2.8 μm (Example 9), respectively. Furthermore, when the specific surface area of the silicic acid-boric acid compound was measured with a specific surface area measuring apparatus (manufactured by Shimadzu Corporation, apparatus name: ASAP2020), all were 1.2 m 2 / g.
（組成分析）
　得られたケイ酸－ホウ酸化合物粒子の化学組成を測定した。まず、ケイ酸－ホウ酸化合物粒子を２．５ｍｏｌ／ＬのＫＯＨ溶液で１２０℃にて加熱密閉分解し、分解液を塩酸酸性下で乾固した。次に塩酸酸性溶液として濾過した後、濾液および残渣を得た。濾液中のＳｉ、Ｂ、Ｆｅ、Ｍｎ、Ｃｏ、およびＮｉ量は、誘導結合発光分光分析装置（セイコーインスツル社製、装置名：ＳＰＳ３１００）を用いて定量した。濾液中のＬｉ、およびＮａ量は原子吸光光度計（日立ハイテクノロジーズ社製、装置名：Ｚ－２３１０）を用いて定量した。Ｓｉ、Ｂ、Ｆｅ、Ｍｎ、Ｃｏ、Ｎｉ、Ｌｉ、およびＮａの定量値から、ＳｉＯ２、Ｂ２Ｏ５、ＦｅＯ、ＭｎＯ、ＣｏＯ、ＮｉＯ、Ｌｉ２Ｏ、およびＮａ２Ｏの量をそれぞれ算出した。さらに、残渣は灰化した後、フッ酸－硫酸で分解処理し、この処理による重量減少をＳｉＯ２とした。全ＳｉＯ２量は、重量減少量から算出される量と濾液中のＳｉＯ２量の合量とした。実施例１～１０で得たケイ酸－ホウ酸化合物粒子の化学組成の定量値を、表２に示す。 (Composition analysis)
The chemical composition of the resulting silicic acid-boric acid compound particles was measured. First, silicic acid-boric acid compound particles were decomposed by heating and sealing with a 2.5 mol / L KOH solution at 120 ° C., and the decomposition solution was dried under hydrochloric acid acidity. Next, after filtration as a hydrochloric acid acidic solution, a filtrate and a residue were obtained. The amounts of Si, B, Fe, Mn, Co, and Ni in the filtrate were quantified using an inductively coupled emission spectroscopic analyzer (manufactured by Seiko Instruments Inc., apparatus name: SPS3100). The amounts of Li and Na in the filtrate were quantified using an atomic absorption photometer (manufactured by Hitachi High-Technologies Corporation, apparatus name: Z-2310). The amounts of SiO 2 , B 2 O 5 , FeO, MnO, CoO, NiO, Li 2 O, and Na 2 O are calculated from the quantitative values of Si, B, Fe, Mn, Co, Ni, Li, and Na, respectively. did. Further, the residue was incinerated and then decomposed with hydrofluoric acid-sulfuric acid, and the weight loss due to this treatment was changed to SiO 2 . The total amount of SiO 2 was the sum of the amount calculated from the weight loss and the amount of SiO 2 in the filtrate. Table 2 shows quantitative values of the chemical composition of the silicic acid-boric acid compound particles obtained in Examples 1 to 10.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
［実施例１８～３５］
（溶融工程）
　溶融物の組成がＬｉ２Ｏ、Ｎａ２Ｏ、ＦｅＯ、ＭｎＯ、ＣｏＯ、ＮｉＯ、ＳｉＯ２、Ｐ２Ｏ５およびＢ２Ｏ３換算量（単位：モル％）で、それぞれ表３に示す割合となるように、炭酸リチウム（Ｌｉ２ＣＯ３）、炭酸ナトリウム（Ｎａ２ＣＯ３）、四酸化三鉄（Ｆｅ３Ｏ４）、二酸化マンガン（ＭｎＯ２）、四酸化三コバルト（Ｃｏ３Ｏ４）、酸化ニッケル（ＮｉＯ）、二酸化ケイ素（ＳｉＯ２）、リン酸二水素アンモニウム（ＮＨ４Ｈ２ＰＯ４）、および酸化ホウ素（Ｂ２Ｏ３）を秤量し、乾式で混合・粉砕して、原料調合物を得た。 [Examples 18 to 35]
(Melting process)
The composition of the melt is Li 2 O, Na 2 O, FeO, MnO, CoO, NiO, SiO 2 , P 2 O 5 and B 2 O 3 equivalent (unit: mol%), respectively, and the ratios shown in Table 3 Lithium carbonate (Li 2 CO 3 ), sodium carbonate (Na 2 CO 3 ), triiron tetroxide (Fe 3 O 4 ), manganese dioxide (MnO 2 ), tricobalt tetroxide (Co 3 O 4 ) , Nickel oxide (NiO), silicon dioxide (SiO 2 ), ammonium dihydrogen phosphate (NH 4 H 2 PO 4 ), and boron oxide (B 2 O 3 ) are weighed, mixed and pulverized in a dry process, A formulation was obtained.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　実施例１と同様に各原料調合物を用いて溶融物を得て、冷却工程を経てフレーク状の固化物を得た。得られた溶融物の組成式を表３の右欄に示す。 In the same manner as in Example 1, a melt was obtained using each raw material formulation, and a flaky solidified product was obtained through a cooling step. The composition formula of the obtained melt is shown in the right column of Table 3.
（粉砕工程）
　冷却工程で得たフレーク状固化物を軽く手で揉んで細かくした後、乳棒と乳鉢とを用いて粗粉砕した。さらに、粉砕媒体としてジルコニア製ボールを用いた遊星ミルで、粗粉砕後の固化物を乾式で粉砕して粉砕物を得た。実施例２０の粉砕物をレーザ回折／散乱式粒度分析計（堀場製作所社製、装置名：ＬＡ－９５０）を用いて粒子径を測定したところ、体積換算のメディアン径は１．８μｍであった。 (Crushing process)
The flake solidified product obtained in the cooling step was lightly kneaded and finely ground, and then coarsely pulverized using a pestle and mortar. Further, the coarsely pulverized solidified product was pulverized in a dry manner using a planetary mill using zirconia balls as a pulverizing medium to obtain a pulverized product. When the particle diameter of the pulverized product of Example 20 was measured using a laser diffraction / scattering particle size analyzer (manufactured by Horiba, Ltd., apparatus name: LA-950), the median diameter in terms of volume was 1.8 μm. .
（加熱工程）
　粉砕工程で得た粉砕物を３体積％Ｈ２－Ａｒ雰囲気におき、それぞれの実施例について、６００℃、７００℃、８００℃、および９００℃の４種類の温度条件で８時間加熱して、－２００℃／時間の速度で冷却（空冷）し、ケイ酸－ホウ酸－リン酸化合物粒子を析出させた。各実施例のうち、加熱工程を７００℃で実施して得た粒子について、Ｘ線回折、粒度分布、組成分析を行った。 (Heating process)
The pulverized product obtained in the pulverization step was placed in a 3% by volume H 2 —Ar atmosphere, and each example was heated for 8 hours at four temperature conditions of 600 ° C., 700 ° C., 800 ° C., and 900 ° C., The mixture was cooled (air cooled) at a rate of −200 ° C./hour to precipitate silicic acid-boric acid-phosphoric acid compound particles. Among the examples, X-ray diffraction, particle size distribution, and composition analysis were performed on particles obtained by carrying out the heating step at 700 ° C.
（Ｘ線回折）
　得られたケイ酸－ホウ酸－リン酸化合物粒子の鉱物相を、Ｘ線回折装置（リガク社製、装置名：ＲＩＮＴ　ＴＴＲIII）を用いて調べた。
　実施１８～２１、２６～３５で得た粒子は、いずれも斜方晶のオリビン型Ｌｉ２ＭＳｉＯ４（Ｋ．Ｚａｇｈｉｂ　ｅｔ　ａｌ．，　Ｊｏｕｒｎａｌ　ｏｆ　Ｐｏｗｅｒ　Ｓｏｕｒｃｅｓ，　１６０，　１３８１－１３８６，　２００６　及び　Ｒ．Ｄｏｍｉｎｋｏ　ｅｔ　ａｌ．，　Ｅｌｅｃｔｒｏｃｈｅｍｉｓｔｒｙ　Ｃｏｍｍｕｎｉｃａｔｉｏｎｓ，　８，　２１７－２２２　（２００６）参照）に類似した回折パターンを示した。該結果から、ケイ酸－ホウ酸－リン酸化合物粒子が結晶であり、かつ、Ａ２ＭＳｉＯ４結晶のＳｉの一部がＰおよびＢが置換された固溶体結晶からなることが確認できた。また、実施例２２～２５で得た粒子は、Ｌｉ２ＭＳｉＯ４、ＬｉＭＢＯ３、ＬｉＭＰＯ４及びこれらの固溶体を含む共晶と考えられる回折パターンを示した。該結果から、ｘおよびｙが０．２＜ｘ＋ｙ≦０．７である場合には、Ｌｉ２ＭＳｉＯ４、ＬｉＭＢＯ３、ＬｉＭＰＯ４およびこれらの固溶体を含む共晶が得られることが確認できた。
　実施例１８、１９、２０、および２１で得た各結晶のＸ線回折パターンを、それぞれ図４の（ａ）、（ｂ）、（ｃ）、（ｄ）に、実施例２２、２３、２４、および２５で得た各結晶のＸ線回折パターンを、それぞれ図５の（ａ）、（ｂ）、（ｃ）、（ｄ）に、実施例３０、３１、および３３で得た各結晶のＸ線回折パターンを、それぞれ図６の（ａ）、（ｂ）、（ｃ）に示す。 (X-ray diffraction)
The mineral phase of the obtained silicic acid-boric acid-phosphoric acid compound particles was examined using an X-ray diffraction apparatus (manufactured by Rigaku Corporation, apparatus name: RINT TTRIII).
The particles obtained in Examples 18 to 21 and 26 to 35 are all orthorhombic olivine type Li 2 MSiO 4 (K. Zaghib et al., Journal of Power Sources, 160, 1381-1386, 2006, and R. Dominko). et al., Electrochemistry Communications, 8, 217-222 (2006)). From the results, it was confirmed that the silicic acid-boric acid-phosphoric acid compound particles were crystals and a part of Si of the A 2 MSiO 4 crystal was a solid solution crystal in which P and B were substituted. Further, the particles obtained in Examples 22 to 25 exhibited diffraction patterns considered to be eutectics containing Li 2 MSiO 4 , LiMBO 3 , LiMPO 4 and their solid solutions. From the results, it was confirmed that when x and y were 0.2 <x + y ≦ 0.7, a eutectic containing Li 2 MSiO 4 , LiMBO 3 , LiMPO 4 and a solid solution thereof was obtained.
The X-ray diffraction patterns of the crystals obtained in Examples 18, 19, 20, and 21 are shown in FIGS. 4 (a), (b), (c), and (d), respectively, in Examples 22, 23, and 24. The X-ray diffraction patterns of the crystals obtained in, and 25 are shown in FIGS. 5 (a), (b), (c), and (d) for the crystals obtained in Examples 30, 31, and 33, respectively. X-ray diffraction patterns are shown in FIGS. 6 (a), 6 (b) and 6 (c), respectively.
（粒度分布）
　実施例１９で得たケイ酸－ホウ酸－リン酸化合物の粒径分布をレーザ回折／散乱式粒度分布測定装置（堀場製作所社製、装置名：ＬＡ－９２０）で測定した。体積換算のメディアン径は２．５μｍであった。さらに、ケイ酸－ホウ酸－リン酸化合物の比表面積を比表面積測定装置（島津製作所社製、装置名：ＡＳＡＰ２０２０）で測定したところ、１．４ｍ２／ｇであった。 (Particle size distribution)
The particle size distribution of the silicic acid-boric acid-phosphoric acid compound obtained in Example 19 was measured with a laser diffraction / scattering particle size distribution analyzer (manufactured by Horiba, Ltd., apparatus name: LA-920). The median diameter in terms of volume was 2.5 μm. Furthermore, when the specific surface area of the silicic acid-boric acid-phosphoric acid compound was measured with a specific surface area measuring device (manufactured by Shimadzu Corporation, device name: ASAP2020), it was 1.4 m 2 / g.
（組成分析）
　得られたケイ酸－ホウ酸－リン酸化合物粒子の化学組成を測定した。まず、ケイ酸－ホウ酸－リン酸化合物粒子を２．５ｍｏｌ／ＬのＫＯＨ溶液で１２０℃にて加熱密閉分解し、分解液を塩酸酸性下で乾固し、再び塩酸酸性溶液として濾過した後、濾液および残渣を得た。濾液中のＳｉ、Ｂ、Ｐ、Ｆｅ、Ｍｎ、Ｃｏ、およびＮｉ量は、誘導結合発光分光分析装置（セイコーインスツル社製、装置名：ＳＰＳ３１００）を用いて定量し、また濾液中のＬｉ、Ｎａは原子吸光光度計（日立ハイテクノロジーズ社製、装置名：Ｚ－２３１０）を用いて定量した。Ｓｉ、Ｂ、Ｐ、Ｆｅ、Ｍｎ、Ｃｏ、Ｎｉ、Ｌｉ、およびＮａの定量値から、ＳｉＯ２、Ｂ２Ｏ３、Ｐ２Ｏ５、ＦｅＯ、ＭｎＯ、ＣｏＯ、ＮｉＯ、Ｌｉ２Ｏ、およびＮａ２Ｏの量をそれぞれ算出した。さらに、残渣は灰化した後、フッ酸－硫酸で分解処理し、この処理による重量減少をＳｉＯ２量とした。全ＳｉＯ２量は、重量減少量から算出される量と濾液中のＳｉＯ２量の合量とした。実施例１８～２５で得たケイ酸－ホウ酸－リン酸化合物粒子の化学組成の定量値を、表４に示す。 (Composition analysis)
The chemical composition of the resulting silicic acid-boric acid-phosphoric acid compound particles was measured. First, silicic acid-boric acid-phosphoric acid compound particles were decomposed by heating and sealing with a 2.5 mol / L KOH solution at 120 ° C., and the decomposition solution was dried under hydrochloric acid acidity and filtered again as hydrochloric acid acidic solution. The filtrate and residue were obtained. The amounts of Si, B, P, Fe, Mn, Co, and Ni in the filtrate are quantified using an inductively coupled emission spectroscopic analyzer (manufactured by Seiko Instruments Inc., apparatus name: SPS3100), and Li, Na was quantified using an atomic absorption photometer (manufactured by Hitachi High-Technologies Corporation, apparatus name: Z-2310). From the quantitative values of Si, B, P, Fe, Mn, Co, Ni, Li, and Na, SiO 2 , B 2 O 3 , P 2 O 5 , FeO, MnO, CoO, NiO, Li 2 O, and Na The amount of 2 O was calculated respectively. Further, the residue was ashed and then decomposed with hydrofluoric acid-sulfuric acid, and the weight loss due to this treatment was defined as the amount of SiO 2 . The total amount of SiO 2 was the sum of the amount calculated from the weight loss and the amount of SiO 2 in the filtrate. Table 4 shows quantitative values of the chemical composition of the silicic acid-boric acid-phosphoric acid compound particles obtained in Examples 18 to 25.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
（実施例３６～４７）
　実施例１～４、１８～２５で溶融、冷却、粗粉砕して得られた粗粉砕物とカーボンブラックとを、粉砕物とカーボンブラック中の炭素量との質量比が９：１となるようにそれぞれ混合し、実施例１と同様に遊星ミルを用いて粉砕した。各実施例における炭素含有粉砕物をＡｒガス中にて６００℃または７００℃の２種類の温度で８時間加熱し、－２００℃／時間の速度で冷却（空冷）して、ケイ酸化合物粒子を得た。該粒子のＸ線回折パターンは、オリビン型ケイ酸鉄リチウムのそれと一致した。実施例３６、３７、３８、および３９において、７００℃で８時間加熱し、－２００℃／時間の速度で冷却（空冷）して、得られたケイ酸－ホウ酸化合物のＸ線回折パターンをそれぞれ図７の（ａ）、（ｂ）、（ｃ）、（ｄ）に示す。実施例３７において、７００℃で８時間加熱して、－２００℃／時間の速度で冷却（空冷）して、得られたケイ酸－ホウ酸化合物の炭素含有量を炭素分析装置（堀場製作所社製、装置名：ＥＭＩＡ－９２０Ｖ）で測定したところ、９．８質量％であった。 (Examples 36 to 47)
The mass ratio of the coarsely pulverized product obtained by melting, cooling and coarsely pulverizing in Examples 1 to 4 and 18 to 25 and carbon black to the mass of carbon in the pulverized product and carbon black was 9: 1. Were mixed with each other and ground using a planetary mill in the same manner as in Example 1. The carbon-containing pulverized product in each example was heated in Ar gas at two temperatures of 600 ° C. or 700 ° C. for 8 hours and cooled (air-cooled) at a rate of −200 ° C./hour to obtain silicate compound particles. Obtained. The X-ray diffraction pattern of the particles was consistent with that of olivine-type lithium iron silicate. In Examples 36, 37, 38, and 39, an X-ray diffraction pattern of the obtained silicic acid-boric acid compound was obtained by heating at 700 ° C. for 8 hours and cooling (air cooling) at a rate of −200 ° C./hour. These are shown in (a), (b), (c), and (d) of FIG. In Example 37, heating was performed at 700 ° C. for 8 hours, and cooling (air cooling) was performed at a rate of −200 ° C./hour, and the carbon content of the obtained silicic acid-boric acid compound was measured using a carbon analyzer (Horiba, Ltd.). Manufactured, device name: EMIA-920V), it was 9.8% by mass.
（実施例４８、４９）
　実施例３および１９で溶融、急冷、粗粉砕して得られた粗粉砕物とカーボンブラックとシュークロース水溶液とを、粉砕物とカーボンブラック中の炭素量とシュークロース中の炭素との質量比で、０．９０：０．０５：０．０５となるように混合し、実施例３６と同様にして、粉砕、加熱してケイ酸化合物粒子を得た。該粒子のＸ線回折パターンは、それぞれ実施例３、および１９と同様にオリビン型ケイ酸鉄リチウムのそれと一致した。実施例４８および４９において、７００℃で８時間加熱し、－２００℃／時間の速度で冷却（空冷）して、得られたケイ酸化合物の炭素含有量を炭素分析装置（堀場製作所社製、装置名：ＥＭＩＡ－９２０Ｖ）で測定したところ、それぞれ７．５質量％（実施例４８）、７．２質量％（実施例４９）であった。また、該粒子の比表面積を測定したところ、それぞれ２５ｍ２／ｇ（実施例４８）、２８ｍ２／ｇ（実施例４９）であった。 (Examples 48 and 49)
The coarsely pulverized product obtained by melting, quenching, and coarsely pulverizing in Examples 3 and 19, the carbon black and the sucrose aqueous solution were mixed in a mass ratio of the pulverized product, the carbon amount in the carbon black, and the carbon in the sucrose. 0.90: 0.05: 0.05, and pulverized and heated in the same manner as in Example 36 to obtain silicate compound particles. The X-ray diffraction pattern of the particles coincided with that of olivine type lithium iron silicate as in Examples 3 and 19, respectively. In Examples 48 and 49, heating was performed at 700 ° C. for 8 hours, and cooling (air cooling) was performed at a rate of −200 ° C./hour, and the carbon content of the obtained silicate compound was measured using a carbon analyzer (manufactured by Horiba, Ltd. (Measurement name: EMIA-920V) was 7.5% by mass (Example 48) and 7.2% by mass (Example 49), respectively. Moreover, when the specific surface area of this particle | grain was measured, they were 25 m < 2 > / g (Example 48) and 28 m < 2 > / g (Example 49), respectively.
［参考例１］
　溶融物の組成がＬｉ２Ｏ、ＦｅＯ、ＳｉＯ２、およびＢ２Ｏ３換算量（単位：モル％）で、２３．７％、５２．６％、２１．１％、および２．６％となるように、炭酸リチウム（Ｌｉ２ＣＯ３）、四酸化三鉄（Ｆｅ３Ｏ４）、二酸化ケイ素（ＳｉＯ２）、および酸化ホウ素（Ｂ２Ｏ３）をそれぞれ秤量し、乾式で混合・粉砕して原料調合物を得た。原料調合物を実施例１と同様に溶融したが、溶融できなかった。該原料調合物の組成は、本発明の式（１）においてａ＝０、ｂ＝２、ｘ＝０．２に相当する。 [Reference Example 1]
The composition of the melt is 23.7%, 52.6%, 21.1%, and 2.6% in terms of Li 2 O, FeO, SiO 2 , and B 2 O 3 (unit: mol%). Lithium carbonate (Li 2 CO 3 ), triiron tetroxide (Fe 3 O 4 ), silicon dioxide (SiO 2 ), and boron oxide (B 2 O 3 ) were weighed, mixed and pulverized in a dry manner. Thus, a raw material formulation was obtained. The raw material formulation was melted in the same manner as in Example 1, but could not be melted. The composition of the raw material formulation corresponds to a = 0, b = 2, and x = 0.2 in the formula (1) of the present invention.
［参考例２］
　溶融物の組成がＬｉ２Ｏ、ＦｅＯ、ＳｉＯ２、およびＢ２Ｏ３換算量（単位：モル％）で、２６．２％、４７．６％、４．８％、および２１．４％となるように、炭酸リチウム（Ｌｉ２ＣＯ３）、四酸化三鉄（Ｆｅ３Ｏ４）、二酸化ケイ素（ＳｉＯ２）、および酸化ホウ素（Ｂ２Ｏ３）をそれぞれ秤量し、乾式で混合・粉砕し、原料調合物を得た。原料調合物を実施例１と同様に溶融したが、溶融できなかった。該原料調合物の組成は、本発明の式（１）においてａ＝０、ｂ＝１、ｘ＝０．９に相当する。 [Reference Example 2]
The composition of the melt was 26.2%, 47.6%, 4.8%, and 21.4% in terms of Li 2 O, FeO, SiO 2 , and B 2 O 3 (unit: mol%). Lithium carbonate (Li 2 CO 3 ), triiron tetroxide (Fe 3 O 4 ), silicon dioxide (SiO 2 ), and boron oxide (B 2 O 3 ) were weighed, mixed and pulverized in a dry manner. Thus, a raw material formulation was obtained. The raw material formulation was melted in the same manner as in Example 1, but could not be melted. The composition of the raw material formulation corresponds to a = 0, b = 1, and x = 0.9 in the formula (1) of the present invention.
［参考例３］
　溶融物の組成がＬｉ２Ｏ、ＦｅＯ、ＳｉＯ２、Ｂ２Ｏ３、およびＰ２Ｏ５換算量（単位：モル％）で、２６．２％、４７．６％、４．８％、１４．２％、および７．１％となるように、炭酸リチウム（Ｌｉ２ＣＯ３）、四酸化三鉄（Ｆｅ３Ｏ４）、二酸化ケイ素（ＳｉＯ２）、酸化ホウ素（Ｂ２Ｏ３）、およびリン酸二水素アンモニウム（ＮＨ４Ｈ２ＰＯ４）をそれぞれ秤量し、乾式で混合・粉砕して原料調合物を得た。原料調合物を実施例１と同様に溶融したが、完全には溶融できなかった。該原料調合物の組成は、本発明の式（３）においてａ＝０、ｂ＝１、ｘ＝０．６、ｘ＝０．３、ｘ＋ｙ＝０．９に相当する。 [Reference Example 3]
The composition of the melt is 26.2%, 47.6%, 4.8%, 14 in terms of Li 2 O, FeO, SiO 2 , B 2 O 3 , and P 2 O 5 (unit: mol%). Lithium carbonate (Li 2 CO 3 ), triiron tetroxide (Fe 3 O 4 ), silicon dioxide (SiO 2 ), boron oxide (B 2 O 3 ), And ammonium dihydrogen phosphate (NH 4 H 2 PO 4 ) were weighed, mixed and pulverized in a dry manner to obtain a raw material formulation. The raw material formulation was melted in the same manner as in Example 1, but could not be completely melted. The composition of the raw material formulation corresponds to a = 0, b = 1, x = 0.6, x = 0.3, and x + y = 0.9 in the formula (3) of the present invention.
［参考例４］
　溶融物の組成がＬｉ２Ｏ、ＦｅＯ、ＳｉＯ２、およびＢ２Ｏ３換算量（単位：モル％）で、３２．８％、３４．５％、３１．０％、および１．７％となるように、炭酸リチウム（Ｌｉ２ＣＯ３）、四酸化三鉄（Ｆｅ３Ｏ４）、二酸化ケイ素（ＳｉＯ２）、および酸化ホウ素（Ｂ２Ｏ３）をそれぞれ秤量し、乾式で混合・粉砕し、原料調合物を得た。該原料調合物を実施例１と同様に、１，４５０℃で溶融した後、－３００℃／時間で冷却し、結晶化物を得た。得られた結晶化物の鉱物相を、ＸＲＤを用いて同定したところ、Ｌｉ２ＳｉＯ３およびＦｅ３Ｏ４を主成分とするものであった。すなわち、冷却工程、粉砕工程および加熱工程を行わない場合には、目的化合物を得ることができない。 [Reference Example 4]
The composition of the melt is 32.8%, 34.5%, 31.0%, and 1.7% in terms of Li 2 O, FeO, SiO 2 , and B 2 O 3 (unit: mol%) Lithium carbonate (Li 2 CO 3 ), triiron tetroxide (Fe 3 O 4 ), silicon dioxide (SiO 2 ), and boron oxide (B 2 O 3 ) were weighed, mixed and pulverized in a dry manner. Thus, a raw material formulation was obtained. In the same manner as in Example 1, the raw material formulation was melted at 1,450 ° C. and then cooled at −300 ° C./hour to obtain a crystallized product. When the mineral phase of the obtained crystallized product was identified using XRD, it was mainly composed of Li 2 SiO 3 and Fe 3 O 4 . That is, the target compound cannot be obtained unless the cooling step, the pulverizing step and the heating step are performed.
［実施例５０～５４：Ｌｉイオン二次電池用正極および評価用電池の製造例］
　実施例１、２、３、１３、および１９において、７００℃で８時間加熱し、－２００℃／時間の速度で冷却（空冷）して得られたケイ酸化合物粒子の粉砕物と、２０質量％ショ糖溶液とを、粉砕物とショ糖中の炭素量との質量比が９５：５となるようにそれぞれ混合、粉砕し、Ｎ２ガス中で、６００℃で２時間加熱し、冷却後粉砕して活物質を得た。該活物質とポリフッ化ビニリデン樹脂（結着剤）とアセチレンブラック（導電材）とを、質量比が８５：５：１０の比率となるように秤量し、Ｎ－メチルピロリドン（溶媒）中で均一になるまで混合してスラリーを製造した。
　次いで、該スラリーをバーコーターで厚さ３０μｍのアルミニウム箔に塗布した。これを空気中にて１２０℃で乾燥させて溶媒を除去した後、ロールプレスで塗工層を圧密化した後、幅１０ｍｍ×長さ４０ｍｍの短冊状に切り出した。 [Examples 50 to 54: Production Examples of Positive Electrode for Li-ion Secondary Battery and Evaluation Battery]
In Examples 1, 2, 3, 13, and 19, a pulverized product of silicate compound particles obtained by heating at 700 ° C. for 8 hours and cooling (air cooling) at a rate of −200 ° C./hour, and 20 mass % Sucrose solution was mixed and pulverized so that the mass ratio of the pulverized product to the amount of carbon in the sucrose was 95: 5, heated in N 2 gas at 600 ° C. for 2 hours, and after cooling The active material was obtained by grinding. The active material, polyvinylidene fluoride resin (binder) and acetylene black (conductive material) are weighed so that the mass ratio is 85: 5: 10, and uniform in N-methylpyrrolidone (solvent) The slurry was mixed until
Next, the slurry was applied to an aluminum foil having a thickness of 30 μm with a bar coater. After drying this at 120 degreeC in the air and removing a solvent, after consolidating the coating layer with the roll press, it cut out to the strip shape of width 10mm * length 40mm.
　塗工層は短冊状アルミニウム箔の先端１０×１０ｍｍの部分を残して剥離し、これを電極とした。得られた電極のロールプレス後の塗工層厚は２０μｍであった。得られた電極は１５０℃で真空乾燥した後、精製Ａｒガスが満たされたグローブボックス中に搬入し、ニッケルメッシュにリチウム箔を圧着した対極と多孔質ポリエチレンフィルム製セパレータを介して対向させ、さらに両側をポリエチレン板で挟んで固定した。 The coating layer was peeled off leaving a 10 × 10 mm tip of strip-shaped aluminum foil, which was used as an electrode. The coating thickness of the obtained electrode after roll pressing was 20 μm. The obtained electrode was vacuum-dried at 150 ° C., then carried into a glove box filled with purified Ar gas, and opposed to a counter electrode in which a lithium foil was pressure-bonded to a nickel mesh with a porous polyethylene film separator. Both sides were fixed with a polyethylene plate.
　対向電極をポリエチレン製ビーカに入れ、六フッ化リン酸リチウムをエチレンカーボネートとエチルメチルカーボネートの混合溶媒（１：１体積比）に１ｍｏｌ／Ｌの濃度で溶解した非水電解液を注入して充分に含浸させた。電解液含浸後の電極をビーカから取り出し、アルミニウムラミネートフィルム袋に入れ、リード線部を取り出して封止して半電池を構成した。この半電池の特性を以下のようにして測定した。 Put the counter electrode in a polyethylene beaker and inject a non-aqueous electrolyte solution of lithium hexafluorophosphate dissolved in a mixed solvent of ethylene carbonate and ethyl methyl carbonate (1: 1 volume ratio) at a concentration of 1 mol / L. Was impregnated. The electrode after impregnation with the electrolytic solution was taken out from the beaker, put in an aluminum laminate film bag, the lead wire part was taken out and sealed to form a half battery. The characteristics of this half-cell were measured as follows.
（Ｌｉイオン二次電池用正極の充放電特性評価）
　得られた半電池を６０℃の恒温槽に入れ、定電流充放電試験機（北斗電工社製、装置名：ＨＪ２０１Ｂ）に接続して充放電試験を行った。電流密度は電極活物質の質量（導電材と結着剤とを除いた質量）当たりの電流値を１５ｍＡ／ｇとして充放電を行った。充電終止電位はＬｉ対極基準で４．３Ｖとし、終止電圧に到達後即座に放電を開始した。放電終止電圧はＬｉ対極基準で１．５Ｖとした。この充放電サイクルを５サイクル繰り返した。５サイクル目の放電容量は、それぞれ１５７ｍＡｈ／ｇ（実施例５０）、１５８ｍＡｈ／ｇ（実施例５１）、１５８ｍＡｈ／ｇ（実施例５２）、２１０ｍＡｈ／ｇ（実施例５３）、および１７１ｍＡｈ／ｇ（実施例５４）であった。 (Charge / discharge characteristic evaluation of positive electrode for Li ion secondary battery)
The obtained half-cell was placed in a constant temperature bath at 60 ° C. and connected to a constant current charge / discharge tester (manufactured by Hokuto Denko Co., Ltd., device name: HJ201B) to conduct a charge / discharge test. The current density was charged / discharged with the current value per mass of the electrode active material (the mass excluding the conductive material and the binder) being 15 mA / g. The charge end potential was 4.3 V with respect to the Li counter electrode, and discharge was started immediately after reaching the end voltage. The end-of-discharge voltage was 1.5 V with respect to the Li counter electrode. This charge / discharge cycle was repeated 5 times. The discharge capacities at the fifth cycle were 157 mAh / g (Example 50), 158 mAh / g (Example 51), 158 mAh / g (Example 52), 210 mAh / g (Example 53), and 171 mAh / g ( Example 54).
［実施例５５～５６］
　実施例４８および４９で得られたケイ酸化合物粒子を活物質として用いて、これと結着剤としてポリフッ化ビニリデン樹脂と導電材としてアセチレンブラックとを、質量比で９０：５：５の比率にする以外は実施例５０と同様にして電極を製造し、その充放電特性を実施例５０と同様にして評価した。１０サイクル目の放電容量は、それぞれ１５５ｍＡｈ／ｇ（実施例５５）、１６８ｍＡｈ／ｇ（実施例５６）であった。 [Examples 55 to 56]
Using the silicic acid compound particles obtained in Examples 48 and 49 as an active material, a polyvinylidene fluoride resin as a binder and acetylene black as a conductive material in a mass ratio of 90: 5: 5 Except that, an electrode was produced in the same manner as in Example 50, and its charge / discharge characteristics were evaluated in the same manner as in Example 50. The discharge capacities at the 10th cycle were 155 mAh / g (Example 55) and 168 mAh / g (Example 56), respectively.
［参考例５］
　参考例４で溶融、冷却、粉砕して得られた結晶化物とカーボンブラックとを溶融物の組成が実施例５０と同様になるようにして電極を製造し、その充放電特性を実施例５０と同様にして評価した。１サイクル目の放電容量は、７ｍＡｈ／ｇであった。 [Reference Example 5]
An electrode was produced from the crystallized product obtained by melting, cooling and pulverizing in Reference Example 4 and carbon black so that the composition of the melt was the same as in Example 50, and the charge / discharge characteristics thereof were as in Example 50. Evaluation was performed in the same manner. The discharge capacity at the first cycle was 7 mAh / g.
　実施例１～４９では、所望の組成のケイ酸－ホウ酸化合物およびケイ酸－ホウ酸－リン酸化合物を簡便に製造することができた。また、製造されたケイ酸－ホウ酸化合物およびケイ酸－ホウ酸－リン酸化合物は、二次電池用正極材料、さらには二次電池として優れた特性を有することを確認した（実施例５０～５６）。 In Examples 1 to 49, a silicic acid-boric acid compound and a silicic acid-boric acid-phosphoric acid compound having a desired composition could be easily produced. In addition, it was confirmed that the produced silicic acid-boric acid compound and silicic acid-boric acid-phosphoric acid compound had excellent characteristics as a positive electrode material for a secondary battery and further as a secondary battery (Examples 50 to 56).
　本発明のケイ酸化合物の製造方法は、ケイ酸化合物の組成制御がしやすく、製造しやすいので有用である。得られたケイ酸化合物は、二次電池用正極材料さらには二次電池に有用である。本発明のケイ酸化合物を正極材料として用いた二次電池は、プラグインハイブリッド自動車や電気自動車に搭載する二次電池として、また、電力貯蔵用の蓄電池として有用である。
　なお、２０１０年１０月２９日に出願された日本特許出願２０１０－２４４７６４号の明細書、特許請求の範囲、図面及び要約書の全内容をここに引用し、本発明の明細書の開示として、取り入れるものである。 The method for producing a silicic acid compound of the present invention is useful because the composition of the silicic acid compound can be easily controlled and produced. The obtained silicic acid compound is useful for a positive electrode material for a secondary battery and further for a secondary battery. A secondary battery using the silicate compound of the present invention as a positive electrode material is useful as a secondary battery mounted in a plug-in hybrid vehicle or an electric vehicle, or as a storage battery for storing power.
It should be noted that the entire contents of the specification, claims, drawings and abstract of Japanese Patent Application No. 2010-244762 filed on October 29, 2010 are cited herein as disclosure of the specification of the present invention. Incorporated.

Claims (16)

  1. 　下式（Ａ）で表される組成を有する溶融物を得る溶融工程、
    　前記溶融物を冷却し固化物を得る冷却工程、
    　前記固化物を粉砕し粉砕物を得る粉砕工程、および
    　前記粉砕物を加熱して下式（Ｂ）で表される組成を有するケイ酸化合物を得る加熱工程、
    をこの順に具備することを特徴とするケイ酸化合物の製造方法。
    　Ａ２－ｄ＋ａＭｂＳｉ１－ｄＤｄＯ４－ｄ＋ｃ１　　　　　（Ａ）
    （式中、元素ＡはＬｉ、ＮａおよびＫからなる群より選ばれる少なくとも１種の元素であり、元素ＭはＦｅ、Ｍｎ、ＣｏおよびＮｉからなる群より選ばれる少なくとも１種の元素であり、Ｄは、Ｂ、または、ＢおよびＰであり、ａは－０．１≦ａ≦０．４であり、ｂは０．７≦ｂ≦１．３であり、ｄは０＜ｄ≦０．７であり、ｃ１はａ、ｂ、およびＭの価数Ｎに依存する数であり、加熱工程後にｃ２となる数である。）
    　　Ａ２－ｄ＋ａＭｂＳｉ１－ｄＤｄＯ４－ｄ＋ｃ２　　　　（Ｂ）
    （式中、Ａ、Ｍ、Ｄ、ａ、ｂ、およびｄは前記と同じ意味を示すが、前記とは独立した値であり、ｃ２はａ、ｂ、およびＭの価数Ｎに依存する数である。）     A melting step for obtaining a melt having a composition represented by the following formula (A):
    A cooling step of cooling the melt to obtain a solidified product,
    A pulverization step of pulverizing the solidified product to obtain a pulverized product, and a heating step of heating the pulverized product to obtain a silicate compound having a composition represented by the following formula (B):
    In this order. A method for producing a silicic acid compound.
    A 2-d + a M b Si 1-d D d O 4-d + c1 (A)
    (In the formula, element A is at least one element selected from the group consisting of Li, Na and K, and element M is at least one element selected from the group consisting of Fe, Mn, Co and Ni, D is B, or B and P, a is −0.1 ≦ a ≦ 0.4, b is 0.7 ≦ b ≦ 1.3, and d is 0 <d ≦ 0. 7 and c1 is a number that depends on the valence N of a, b, and M, and is a number that becomes c2 after the heating step.)
    A 2-d + a M b Si 1-d D d O 4-d + c2 (B)
    (In the formula, A, M, D, a, b, and d have the same meanings as described above, but are independent values, and c2 is a number that depends on the valence N of a, b, and M. .)
  2. 　前記式（Ａ）で表される組成を有する溶融物が、下式（１）で表される組成を有する溶融物であり、前記式（Ｂ）で表される組成を有するケイ酸化合物が、下式（２）で表される組成を有するケイ酸－ホウ酸化合物である、請求項１に記載のケイ酸化合物の製造方法。
    　Ａ２－ｘ＋ａＭｂＳｉ１－ｘＢｘＯ４－ｘ＋ｃ１１　　　　（１）
    　Ａ２－ｘ＋ａＭｂＳｉ１－ｘＢｘＯ４－ｘ＋ｃ１２　　　　（２）
    （式中、Ａ、Ｍ、ａ、およびｂは、それぞれ前記と同じ意味を示し、ｘは０＜ｘ≦０．７であり、ｃ１１はａ、ｂ、およびＭの価数Ｎに依存する数であり、加熱工程後にｃ１２となる数であり、ｃ１２はａ、ｂ、およびＭの価数Ｎに依存する数である。ただし、式（１）と式（２）において、ａ、ｂ、およびｘは独立した値を示す。）     The melt having the composition represented by the formula (A) is a melt having the composition represented by the following formula (1), and the silicate compound having the composition represented by the formula (B) is: The method for producing a silicic acid compound according to claim 1, which is a silicic acid-boric acid compound having a composition represented by the following formula (2).
    A 2-x + a M b Si 1-x B x O 4-x + c11 (1)
    A 2-x + a M b Si 1-x B x O 4-x + c12 (2)
    (In the formula, A, M, a, and b each have the same meaning as described above, x is 0 <x ≦ 0.7, and c11 is a number that depends on the valence N of a, b, and M. And c12 is a number that depends on the valence N of a, b, and M. In Formula (1) and Formula (2), a, b, and x represents an independent value.)
  3. 　前記溶融工程が、
    　元素Ａを含む化合物が、Ａの炭酸塩、Ａの炭酸水素塩、Ａの水酸化物、Ａのケイ酸塩、Ａのリン酸塩、Ａのリン酸水素塩、Ａのホウ酸塩、Ａの硝酸塩、Ａの塩化物、Ａの硫酸塩、Ａの酢酸塩およびＡのシュウ酸塩からなる群より選ばれる少なくとも１種（ただし、該１種以上の一部または全部は、それぞれ、水和塩を形成していてもよい。）として含まれ、
    　元素Ｍを含む化合物が、Ｍの酸化物、Ｍのオキシ水酸化物、Ｍのケイ酸塩、Ｍのホウ酸塩、Ｍの金属、Ｍのリン酸塩、Ｍの塩化物、Ｍの硝酸塩、Ｍの硫酸塩およびＭの有機塩からなる群より選ばれる少なくとも１種として含まれ、
    　Ｓｉを含む化合物が、酸化ケイ素、Ａのケイ酸塩、Ｍのケイ酸塩およびケイ素のアルコキシドからなる群より選ばれる少なくとも１種として含まれ、
    　Ｂを含む化合物が、酸化ホウ素、ホウ酸、Ａのホウ酸塩およびＭのホウ酸塩からなる群より選ばれる少なくとも１種として含まれる、
    原料調合物を加熱して、前記式（１）で表される組成を有する溶融物を得る工程である、請求項２に記載のケイ酸化合物の製造方法。     The melting step is
    The compound containing element A is A carbonate, A bicarbonate, A hydroxide, A silicate, A phosphate, A hydrogen phosphate, A borate, A At least one selected from the group consisting of nitrates of A, chlorides of A, sulfates of A, acetates of A and oxalates of A (provided that some or all of the one or more are hydrated, respectively) A salt may be formed.)
    The compound containing element M is M oxide, M oxyhydroxide, M silicate, M borate, M metal, M phosphate, M chloride, M nitrate, Included as at least one selected from the group consisting of M sulfate and M organic salt;
    A compound containing Si is included as at least one selected from the group consisting of silicon oxide, A silicate, M silicate, and silicon alkoxide,
    The compound containing B is included as at least one selected from the group consisting of boron oxide, boric acid, A borate and M borate.
    The manufacturing method of the silicic acid compound of Claim 2 which is a process of heating a raw material formulation and obtaining the melt which has a composition represented by said Formula (1).
  4. 　前記式（Ａ）で表される組成を有する溶融物が、下式（３）で表される組成を有する溶融物であり、前記式（Ｂ）で表される組成を有するケイ酸化合物が、下式（４）で表される組成を有するケイ酸－ホウ酸－リン酸化合物である、請求項１に記載のケイ酸化合物の製造方法。
    　Ａ２－ｘ－ｙ＋ａＭｂＳｉ１－（ｘ＋ｙ）ＢｘＰｙＯ４－ｘ＋ｃ２１　　　　　（３）
    　Ａ２－ｘ－ｙ＋ａＭｂＳｉ１－（ｘ＋ｙ）ＢｘＰｙＯ４－ｘ＋ｃ２２　　　　　（４）
    （式中、Ａ、Ｍ、ａ、およびｂは、それぞれ前記と同じ意味を示し、ｘは０＜ｘ≦０．７であり、ｙは０＜ｙ≦０．７であり、０＜（ｘ＋ｙ）≦０．７を満たし、ｃ２１はａ、ｂ、およびＭの価数Ｎに依存する数であり、加熱工程後にｃ２２となる数であり、ｃ２２はａ、ｂ、およびＭの価数Ｎに依存する数である。ただし、式（３）と式（４）において、ａ、ｂ、ｘ、およびｙは独立した値を示す。）     The melt having the composition represented by the formula (A) is a melt having the composition represented by the following formula (3), and the silicic acid compound having the composition represented by the formula (B) is: The method for producing a silicic acid compound according to claim 1, which is a silicic acid-boric acid-phosphoric acid compound having a composition represented by the following formula (4):
    A 2-x-y + a M b Si 1- (x + y) B x P y O 4-x + c21 (3)
    A 2-x-y + a M b Si 1- (x + y) B x P y O 4-x + c22 (4)
    (Wherein A, M, a, and b each have the same meaning as described above, x is 0 <x ≦ 0.7, y is 0 <y ≦ 0.7, and 0 <(x + y ) ≦ 0.7, c21 is a number that depends on the valence N of a, b, and M, and is a number that becomes c22 after the heating step, and c22 is the valence N of a, b, and M. (In formulas (3) and (4), a, b, x, and y represent independent values.)
  5. 　前記溶融工程が、
    　元素Ａを含む化合物が、Ａの炭酸塩、Ａの炭酸水素塩、Ａの水酸化物、Ａのケイ酸塩、Ａのリン酸塩、Ａのリン酸水素塩、Ａのホウ酸塩、Ａの硝酸塩、Ａの塩化物、Ａの硫酸塩、Ａの酢酸塩およびＡのシュウ酸塩からなる群より選ばれる少なくとも１種（ただし、該１種以上の一部または全部は、それぞれ、水和塩を形成していてもよい。）として含まれ、
    　元素Ｍを含む化合物が、Ｍの酸化物、Ｍのオキシ水酸化物、Ｍのケイ酸塩、Ｍのホウ酸塩、Ｍの金属、Ｍのリン酸塩、Ｍの塩化物、Ｍの硝酸塩、Ｍの硫酸塩およびＭの有機塩からなる群より選ばれる少なくとも１種として含まれ、
    　Ｓｉを含む化合物が、酸化ケイ素、Ａのケイ酸塩、Ｍのケイ酸塩およびケイ素のアルコキシドからなる群より選ばれる少なくとも１種として含まれ、
    　Ｂを含む化合物が、酸化ホウ素、ホウ酸、Ａのホウ酸塩、Ｍのホウ酸塩およびリン酸ホウ素からなる群より選ばれる少なくとも１種として含まれ、
    　Ｐを含む化合物が、酸化リン、リン酸アンモニウム、リン酸水素アンモニウム、リン酸ホウ素、リン酸、ポリリン酸、亜リン酸、次亜リン酸、Ａのリン酸塩およびＭのリン酸塩からなる群より選ばれる少なくとも１種として含まれる、
    原料調合物を加熱して、前記式（３）で表される組成を有する溶融物を得る工程である、請求項４に記載のケイ酸化合物の製造方法。     The melting step is
    The compound containing element A is A carbonate, A bicarbonate, A hydroxide, A silicate, A phosphate, A hydrogen phosphate, A borate, A At least one selected from the group consisting of nitrates of A, chlorides of A, sulfates of A, acetates of A and oxalates of A (provided that some or all of the one or more are hydrated, respectively) A salt may be formed.)
    The compound containing element M is M oxide, M oxyhydroxide, M silicate, M borate, M metal, M phosphate, M chloride, M nitrate, Included as at least one selected from the group consisting of M sulfate and M organic salt;
    A compound containing Si is included as at least one selected from the group consisting of silicon oxide, A silicate, M silicate, and silicon alkoxide,
    A compound containing B is included as at least one selected from the group consisting of boron oxide, boric acid, A borate, M borate and boron phosphate;
    The compound containing P consists of phosphorus oxide, ammonium phosphate, ammonium hydrogen phosphate, boron phosphate, phosphoric acid, polyphosphoric acid, phosphorous acid, hypophosphorous acid, A phosphate and M phosphate Included as at least one selected from the group,
    The manufacturing method of the silicic acid compound of Claim 4 which is a process of heating a raw material formulation and obtaining the melt which has a composition represented by said Formula (3).
  6. 　前記元素ＡがＬｉである、請求項１～５のいずれか一項に記載のケイ酸化合物の製造方法。 The method for producing a silicate compound according to any one of claims 1 to 5, wherein the element A is Li.
  7. 　前記元素ＭがＦｅおよびＭｎからなる群より選ばれる少なくとも１種である、請求項１～６のいずれか一項に記載のケイ酸化合物の製造方法。 The method for producing a silicate compound according to any one of claims 1 to 6, wherein the element M is at least one selected from the group consisting of Fe and Mn.
  8. 　前記式（１）で表される組成を有する溶融物が、下式（５Ａ）で表される組成を有する溶融物であり、前記式（２）で表される組成を有するケイ酸－ホウ酸化合物が、下式（５）で表される組成を有するオリビン型結晶粒子を含む化合物である、請求項２に記載のケイ酸化合物の製造方法。
    　Ｌｉ２－ｘ＋ａ（ＦｅｍＭｎ１－ｍ）ｂＳｉ１－ｘＢｘＯ４－ｘ＋ｃ１１　（５Ａ）
    　Ｌｉ２－ｘ＋ａ（ＦｅｍＭｎ１－ｍ）ｂＳｉ１－ｘＢｘＯ４－ｘ＋ｃ１２　（５）
    （式中、ａ、ｂ、ｃ１１、ｃ１２、およびｘは前記と同じ意味を示し、ｍは０≦ｍ≦１である。ただし、式（５Ａ）と式（５）において、ａ、ｂ、ｘ、およびｍは独立した値を示す。）     The melt having the composition represented by the formula (1) is a melt having the composition represented by the following formula (5A), and the silicic acid-boric acid having the composition represented by the formula (2) The manufacturing method of the silicic acid compound of Claim 2 whose compound is a compound containing the olivine type | mold crystal particle which has a composition represented by the following Formula (5).
    Li 2-x + a (Fe m Mn 1-m) b Si 1-x B x O 4-x + c11 (5A)
    Li 2-x + a (Fe m Mn 1-m ) b Si 1-x B x O 4-x + c12 (5)
    (Wherein a, b, c11, c12, and x have the same meaning as described above, and m is 0 ≦ m ≦ 1, provided that in formulas (5A) and (5), a, b, x , And m are independent values.)
  9. 　前記式（３）で表される組成を有する溶融物が、下式（６Ａ）で表される組成を有する溶融物であり、前記式（４）で表される組成を有するケイ酸－ホウ酸－リン酸化合物が、下式（６）で表される組成を有するオリビン型結晶粒子を含む化合物である、請求項４に記載のケイ酸化合物の製造方法。
    　Ｌｉ２－ｘ－ｙ＋ａ（ＦｅｍＭｎ１－ｍ）ｂＳｉ１－（ｘ＋ｙ）ＢｘＰｙＯ４－ｘ＋ｃ２１　　（６Ａ）
    　Ｌｉ２－ｘ－ｙ＋ａ（ＦｅｍＭｎ１－ｍ）ｂＳｉ１－（ｘ＋ｙ）ＢｘＰｙＯ４－ｘ＋ｃ２２　（６）
    （式中、ａ、ｂ、ｃ２１、ｃ２２、ｘおよびｙは前記と同じ意味を示し、ｍは０≦ｍ≦１である。ただし、式（６Ａ）と式（６）において、ａ、ｂ、ｘ、ｙ、およびｍは独立した値を示す。）     The melt having the composition represented by the formula (3) is a melt having the composition represented by the following formula (6A), and the silicic acid-boric acid having the composition represented by the formula (4) The method for producing a silicic acid compound according to claim 4, wherein the phosphoric acid compound is a compound containing olivine type crystal particles having a composition represented by the following formula (6).
    Li 2-x-y + a (Fe m Mn 1-m) b Si 1- (x + y) B x P y O 4-x + c21 (6A)
    Li 2-x-y + a (Fe m Mn 1-m) b Si 1- (x + y) B x P y O 4-x + c22 (6)
    (Wherein a, b, c21, c22, x and y have the same meaning as described above, and m is 0 ≦ m ≦ 1, provided that in formula (6A) and formula (6), a, b, x, y, and m are independent values.)
  10. 　前記冷却工程において、冷却速度を－１０３℃／秒～－１０１０℃／秒とする、請求項１～９のいずれか一項に記載のケイ酸化合物の製造方法。 The method for producing a silicate compound according to any one of claims 1 to 9, wherein in the cooling step, a cooling rate is set to -10 3 ° C / second to -10 10 ° C / second.
  11. 　前記粉砕工程において、前記固化物に、有機化合物および炭素粉末からなる群より選択される少なくとも１種の炭素源を含ませ、かつ該炭素源中の炭素換算量（質量）の割合が、固化物の質量と、該炭素源中の炭素換算量（質量）との合計質量に対して０．１～２０質量％である、請求項１～１０のいずれか一項に記載のケイ酸化合物の製造方法。 In the pulverization step, the solidified product contains at least one carbon source selected from the group consisting of an organic compound and a carbon powder, and a ratio of a carbon conversion amount (mass) in the carbon source is a solidified product. The production of a silicic acid compound according to any one of claims 1 to 10, which is 0.1 to 20% by mass relative to the total mass of the mass of the carbon and the carbon equivalent amount (mass) in the carbon source. Method.
  12. 　前記加熱工程を５００～１，０００℃に加熱することにより行う、請求項１～１１のいずれか一項に記載のケイ酸化合物の製造方法。 The method for producing a silicate compound according to any one of claims 1 to 11, wherein the heating step is performed by heating to 500 to 1,000 ° C.
  13. 　請求項１～１２のいずれか一項に記載の製造方法によってケイ酸化合物を得て、次に該ケイ酸化合物を二次電池用正極材料に用いて二次電池用正極を製造することを特徴とする二次電池用正極の製造方法。 A silicate compound is obtained by the production method according to any one of claims 1 to 12, and then a positive electrode for a secondary battery is produced using the silicate compound as a positive electrode material for a secondary battery. A method for producing a positive electrode for a secondary battery.
  14. 　請求項１３に記載の製造方法で二次電池用正極を得て、次に、該二次電池用正極を用いて二次電池を製造することを特徴とする二次電池の製造方法。 A method for producing a secondary battery, comprising: obtaining a positive electrode for a secondary battery by the production method according to claim 13, and then producing a secondary battery using the positive electrode for the secondary battery.
  15. 　下式（２）で表される組成を有することを特徴とするケイ酸－ホウ酸化合物。
    　Ａ２－ｘ＋ａＭｂＳｉ１－ｘＢｘＯ４－ｘ＋ｃ１２　　　　（２）
    （式中、元素ＡはＬｉ、ＮａおよびＫからなる群より選ばれる少なくとも１種の元素であり、元素ＭはＦｅ、Ｍｎ、ＣｏおよびＮｉからなる群より選ばれる少なくとも１種の元素であり、ａは－０．１≦ａ≦０．４であり、ｂは０．７≦ｂ≦１．３であり、ｘは０＜ｘ≦０．７であり、ｃ１２はａ、ｂ、およびＭの価数Ｎに依存する数である。）     A silicic acid-boric acid compound having a composition represented by the following formula (2):
    A 2-x + a M b Si 1-x B x O 4-x + c12 (2)
    (In the formula, element A is at least one element selected from the group consisting of Li, Na and K, and element M is at least one element selected from the group consisting of Fe, Mn, Co and Ni, a is −0.1 ≦ a ≦ 0.4, b is 0.7 ≦ b ≦ 1.3, x is 0 <x ≦ 0.7, and c12 is a, b, and M (The number depends on the valence N.)
  16. 　下式（４）で表される組成を有することを特徴とするケイ酸－ホウ酸－リン酸化合物。
    　Ａ２－ｘ－ｙ＋ａＭｂＳｉ１－（ｘ＋ｙ）ＢｘＰｙＯ４－ｘ＋ｃ２２　　　　　（４）
    （式中、元素ＡはＬｉ、ＮａおよびＫからなる群より選ばれる少なくとも１種の元素であり、元素ＭはＦｅ、Ｍｎ、ＣｏおよびＮｉからなる群より選ばれる少なくとも１種の元素であり、ａは－０．１≦ａ≦０．４であり、ｂは０．７≦ｂ≦１．３であり、ｘは０＜ｘ≦０．７であり、ｙは０＜ｙ≦０．７であり、０＜（ｘ＋ｙ）≦０．７を満たし、ｃ２２はａ、ｂ、およびＭの価数Ｎに依存する数である。）     A silicic acid-boric acid-phosphoric acid compound having a composition represented by the following formula (4):
    A 2-x-y + a M b Si 1- (x + y) B x P y O 4-x + c22 (4)
    (In the formula, element A is at least one element selected from the group consisting of Li, Na and K, and element M is at least one element selected from the group consisting of Fe, Mn, Co and Ni, a is −0.1 ≦ a ≦ 0.4, b is 0.7 ≦ b ≦ 1.3, x is 0 <x ≦ 0.7, and y is 0 <y ≦ 0.7. And 0 <(x + y) ≦ 0.7, and c22 is a number depending on the valence N of a, b, and M.)
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JP2013008483A (en) * 2011-06-23 2013-01-10 Taiheiyo Cement Corp Method for producing cathode active material for lithium-ion battery
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CN113403644A (en) * 2021-06-25 2021-09-17 北京航空航天大学 Catalyst for electrocatalytic carbon dioxide reduction reaction and preparation method and application thereof
CN113430540A (en) * 2021-06-25 2021-09-24 北京航空航天大学 Monoatomic catalyst, preparation method and application thereof
CN114171806A (en) * 2021-12-01 2022-03-11 国网河北省电力有限公司电力科学研究院 Lead-acid storage battery active catalyst, lead-acid storage battery activator and preparation method thereof
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