WO2016151891A1 - 二次電池用正極活物質及びその製造方法 - Google Patents
二次電池用正極活物質及びその製造方法 Download PDFInfo
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- 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
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- 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
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- H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
- H01M4/624—Electric conductive fillers
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- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
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- H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
- H01M2004/028—Positive electrodes
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- 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 positive electrode active material for a secondary battery in which one or two kinds selected from carbon obtained by carbonizing an oxide with a water-insoluble conductive carbon material and a water-soluble carbon material, and a metal fluoride are supported together. Concerning substances.
- lithium ion secondary batteries are widely known as the most excellent secondary batteries that operate near room temperature.
- lithium-containing olivine-type phosphate metal salts such as Li (Fe, Mn) PO 4 and Li 2 (Fe, Mn) SiO 4 are more resource-constrained than lithium transition metal oxides such as LiCoO 2. Therefore, it is possible to exhibit high safety, and therefore, it is an optimum positive electrode material for obtaining a high-output and large-capacity lithium ion secondary battery.
- these compounds have the property that it is difficult to sufficiently increase the conductivity due to the crystal structure, and there is room for improvement in the diffusibility of lithium ions. Has been made.
- Patent Document 2 discloses that after the firing treatment of the raw material mixture containing the carbonaceous material precursor, the water content is reduced to a certain value or less by performing pulverization treatment and classification treatment in a dry atmosphere.
- Technology is disclosed.
- a predetermined lithium phosphate compound, lithium silicate compound, and the like and a conductive carbon material are mixed by a wet ball mill, and then a mechanochemical treatment is performed so that the conductive carbon material is uniformly applied to the surface.
- a technique for obtaining a composite oxide deposited is disclosed.
- Patent Document 4 discloses a sodium ion secondary battery active material using marisite-type NaMnPO 4
- Patent Document 5 discloses a positive electrode containing sodium phosphate transition metal having an olivine structure. An active material is disclosed, and any literature indicates that a high-performance sodium ion secondary battery can be obtained.
- the surface of the lithium phosphate compound or the like is not sufficiently covered with the carbon source, and a part of the surface is exposed. It has been found that it is difficult to obtain a positive electrode active material for a secondary battery in which the moisture content is increased and the battery properties such as cycle characteristics are sufficiently high.
- an object of the present invention is to provide a positive electrode active material for a secondary battery that can effectively suppress moisture adsorption and a method for manufacturing the same, in order to obtain a high-performance lithium ion secondary battery or a sodium ion secondary battery. It is to provide.
- specific oxides include one or more selected from carbon obtained by carbonizing a water-insoluble conductive carbon material and a water-soluble carbon material, and a specific amount of metal.
- carbon obtained by carbonizing a water-insoluble conductive carbon material and / or a water-soluble carbon material, and a metal fluoride both have an oxide surface. Since it is possible to effectively coat and effectively suppress moisture adsorption, lithium ion or sodium ion has been found to be extremely useful as a positive electrode active material for a secondary battery that can effectively carry electric conduction, and the present invention. It came to complete.
- the present invention includes at least the following formula (A), (B) or (C) containing iron or manganese: LiFe a Mn b M c PO 4 (A) (In the formula (A), M represents Mg, Ca, Sr, Y, Zr, Mo, Ba, Pb, Bi, La, Ce, Nd, or Gd.
- Li 2 Fe d Mn e N f SiO 4 (B) (In the formula (B), N represents Ni, Co, Al, Zn, V, or Zr.
- D, e, and f are 0 ⁇ d ⁇ 1, 0 ⁇ e ⁇ 1, and 0 ⁇ f ⁇ 1, 2d + 2e +.
- the present invention also provides an oxide X by subjecting a slurry water a containing a lithium compound or sodium compound, a phosphoric acid compound or a silicic acid compound, and a metal salt containing at least an iron compound or a manganese compound to a hydrothermal reaction.
- Step (I-1) A step (II-1) of obtaining a composite A by adding a water-insoluble conductive carbon material to the obtained oxide X and dry-mixing, and the obtained composite A to 100 parts by mass of the composite
- a step of adding 0.1 to 40 parts by mass of a metal fluoride precursor, wet mixing and firing III-1)
- the manufacturing method of the said positive electrode active material for secondary batteries provided with these is provided.
- the present invention provides a hydrothermal reaction of slurry water b containing a lithium compound or sodium compound, a phosphoric acid compound or silicic acid compound, and a metal salt containing at least an iron compound or a manganese compound and containing a water-soluble carbon material.
- Step (I-2) for obtaining composite D by attaching to 0.1 to 40 parts by weight of metal fluoride metal fluoride precursor to 100 parts by weight of composite in the obtained composite D Adding, wet-mixing and firing (II-2)
- the manufacturing method of the positive electrode active material for secondary batteries provided with these is provided.
- the carbon obtained by carbonizing the water-insoluble conductive carbon material and / or the water-soluble carbon material and the specific amount of metal fluoride are effectively supported on the predetermined oxide while complementing each other.
- lithium ions or sodium ions effectively carry electric conduction, and various Excellent battery characteristics such as cycle characteristics can be stably exhibited even in a different use environment.
- the oxide used in the present invention contains at least iron or manganese and has the following formula (A), (B) or (C): LiFe a Mn b M c PO 4 (A) (In the formula (A), M represents Mg, Ca, Sr, Y, Zr, Mo, Ba, Pb, Bi, La, Ce, Nd, or Gd.
- Li 2 Fe d Mn e N f SiO 4 (B) (In the formula (B), N represents Ni, Co, Al, Zn, V, or Zr.
- D, e, and f are 0 ⁇ d ⁇ 1, 0 ⁇ e ⁇ 1, 0 ⁇ f ⁇ 1, and 2d + 2e +.
- oxides all have an olivine structure and contain at least iron or manganese.
- oxide represented by the above formula (A) or (B) a positive electrode active material for a lithium ion battery is obtained, and when the oxide represented by the above formula (C) is used.
- a positive electrode active material for a sodium ion battery is obtained.
- the oxide represented by the above formula (A) is an olivine-type transition metal lithium compound containing at least iron (Fe) and manganese (Mn) as so-called transition metals.
- M represents Mg, Ca, Sr, Y, Zr, Mo, Ba, Pb, Bi, La, Ce, Nd, or Gd, and is preferably Mg, Zr, Mo, or Co.
- a is 0 ⁇ a ⁇ 1, preferably 0.01 ⁇ a ⁇ 0.99, and more preferably 0.1 ⁇ a ⁇ 0.9.
- b is 0 ⁇ b ⁇ 1, preferably 0.01 ⁇ b ⁇ 0.99, and more preferably 0.1 ⁇ b ⁇ 0.9.
- olivine-type transition metal lithium compound represented by the above formula (A) include LiFe 0.2 Mn 0.8 PO 4 , LiFe 0.9 Mn 0.1 PO 4 , LiFe 0.15 Mn 0.75 Mg 0.1 PO 4 , LiFe Examples include 0.19 Mn 0.75 Zr 0.03 PO 4 , and among them, LiFe 0.2 Mn 0.8 PO 4 is preferable.
- the oxide represented by the above formula (B) is a so-called olivine-type transition metal lithium compound containing at least iron (Fe) and manganese (Mn) as transition metals.
- N represents Ni, Co, Al, Zn, V, or Zr, and is preferably Co, Al, Zn, V, or Zr.
- d is 0 ⁇ d ⁇ 1, preferably 0 ⁇ d ⁇ 1, and more preferably 0.1 ⁇ d ⁇ 0.6.
- e is 0 ⁇ d ⁇ 1, preferably 0 ⁇ e ⁇ 1, and more preferably 0.1 ⁇ e ⁇ 0.6.
- f is 0 ⁇ f ⁇ 1, preferably 0 ⁇ f ⁇ 1, and more preferably 0.05 ⁇ f ⁇ 0.4.
- olivine-type transition metal lithium compound represented by the above formula (B) include, for example, Li 2 Fe 0.45 Mn 0.45 Co 0.1 SiO 4 , Li 2 Fe 0.36 Mn 0.54 Al 0.066 SiO 4 , Li 2 Fe 0.45 Mn 0.45 Zn 0.1 SiO 4 , Li 2 Fe 0.36 Mn 0.54 V 0.066 SiO 4 , Li 2 Fe 0.282 Mn 0.658 Zr 0.02 SiO 4 and the like can be mentioned, among which Li 2 Fe 0.282 Mn 0.658 Zr 0.02 SiO 4 is preferable.
- the oxide represented by the formula (C) is an olivine-type transition metal sodium phosphate compound containing iron (Fe) and manganese (Mn) as at least transition metals.
- Q represents Mg, Ca, Co, Sr, Y, Zr, Mo, Ba, Pb, Bi, La, Ce, Nd, or Gd, and is preferably Mg, Zr, Mo, or Co.
- g is 0 ⁇ g ⁇ 1, and preferably 0 ⁇ g ⁇ 1.
- h is 0 ⁇ h ⁇ 1, and preferably 0.5 ⁇ h ⁇ 1.
- i is 0 ⁇ i ⁇ 1, preferably 0 ⁇ i ⁇ 0.5, and more preferably 0 ⁇ i ⁇ 0.3.
- olivine-type transition metal sodium phosphate compound represented by the above formula (C) include, for example, NaFe 0.2 Mn 0.8 PO 4 , NaFe 0.9 Mn 0.1 PO 4 , NaFe 0.15 Mn 0.7 Mg 0.15 PO 4 , NaFe Examples include 0.19 Mn 0.75 Zr 0.03 PO 4 , NaFe 0.19 Mn 0.75 Mo 0.03 PO 4 , NaFe 0.15 Mn 0.7 Co 0.15 PO 4 , and NaFe 0.2 Mn 0.8 PO 4 is preferred.
- the positive electrode active material for a secondary battery according to the present invention is carbon obtained by carbonizing an oxide represented by the above formula (A), (B) or (C) with a water-insoluble conductive carbon material and a water-soluble carbon material.
- a water-insoluble conductive carbon material and a water-soluble carbon material.
- One or two selected from (carbon derived from a water-soluble carbon material) and 0.1 to 5% by mass of a metal fluoride are supported.
- the oxide is made to carry one or two kinds selected from carbon obtained by carbonizing a water-insoluble conductive carbon material and a water-soluble carbon material and a specific amount of metal fluoride, One or two selected from the water-insoluble conductive carbon material and the carbon obtained by carbonizing the water-soluble carbon material, or one of the metal fluorides is coated on the oxide surface, and the oxidation is performed without the presence of one of them.
- One or two kinds selected from carbon obtained by carbonizing a water-insoluble conductive carbon material and a water-soluble carbon material, or the other of metal fluorides, is effectively supported on a portion where the object surface is exposed.
- the positive electrode active material for a secondary battery of the present invention specifically, for example, a water-insoluble conductive carbon material and 0.1 to 5% by mass of a metal fluoride are supported on the oxide.
- the secondary battery positive electrode active material (P-1) and the above oxide are loaded with carbon obtained by carbonizing a water-soluble carbon material and 0.1 to 5% by mass of a metal fluoride.
- the secondary battery positive electrode active material (P-1) may be formed by further supporting carbon obtained by carbonizing a water-soluble carbon material on the oxide as necessary.
- the water-insoluble conductive carbon material supported on the oxide represented by the above formula (A), (B) or (C) means that the amount dissolved in 100 g of water at 25 ° C. is carbon of the water-insoluble conductive carbon material.
- the water-insoluble conductive carbon material include one or more selected from graphite, acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black. Among these, ketjen black or graphite is preferable from the viewpoint of reducing the amount of adsorbed moisture.
- the graphite may be any of artificial graphite (scale-like, lump-like, earthy, graphene) or natural graphite.
- the BET specific surface area of the water-insoluble conductive carbon material that can be used is preferably 1 to 750 m 2 / g, more preferably 3 to 500 m 2 / g, from the viewpoint of effectively reducing the amount of adsorbed water. Further, from the same viewpoint, the average particle size of the water-insoluble conductive carbon material is preferably 0.5 to 20 ⁇ m, more preferably 1.0 to 15 ⁇ m.
- the water-insoluble conductive carbon material is present in the positive electrode active material for a secondary battery of the present invention as carbon supported on the oxide.
- the carbon atom equivalent amount of the water-insoluble conductive carbon material is preferably 0.5 to 7% by mass, more preferably 0.7 to 6% by mass in the positive electrode active material for a secondary battery of the present invention. More preferably 0.85 to 5.5% by mass.
- the amount in terms of carbon atoms of the water-insoluble conductive carbon material present in the positive electrode active material for secondary batteries can be confirmed by the amount of carbon measured using a carbon / sulfur analyzer.
- the carbon atom equivalent amount of the water-insoluble conductive carbon material present in the positive electrode active material for the secondary battery is determined from the carbon amount measured using a carbon / sulfur analyzer. This can be confirmed by subtracting the amount of water-soluble carbon material added in terms of carbon atoms.
- the water-soluble carbon material supported as carbon carbonized by the oxide represented by the above formula (A), (B) or (C) is equivalent to carbon atom of the water-soluble carbon material in 100 g of water at 25 ° C.
- the water-soluble carbon material include one or more selected from saccharides, polyols, polyethers, and organic acids.
- monosaccharides such as glucose, fructose, galactose and mannose
- disaccharides such as maltose, sucrose and cellobiose
- polysaccharides such as starch and dextrin
- polyols and polyethers such as diol, propanediol, polyvinyl alcohol, and glycerin
- organic acids such as citric acid, tartaric acid, and ascorbic acid.
- glucose, fructose, sucrose, and dextrin are preferable, and glucose is more preferable from the viewpoint of improving the solubility and dispersibility in a solvent and effectively functioning as a carbon material.
- the carbon atom equivalent of the water-soluble carbon material is present in the positive electrode active material for the secondary battery of the present invention as carbon supported by the oxide by carbonization of the water-soluble carbon material.
- the carbon atom equivalent amount of the water-soluble carbon material is preferably 0.1 to 4% by mass, more preferably 0.2 to 3.5% by mass in the positive electrode active material for a secondary battery of the present invention. More preferably, it is 0.3 to 3% by mass.
- the amount in terms of carbon atoms of the water-soluble carbon material present in the positive electrode active material for secondary battery can be confirmed by the amount of carbon measured using a carbon / sulfur analyzer.
- the carbon atom equivalent amount of the water-soluble carbon material present in the positive electrode active material for secondary batteries is calculated from the carbon amount measured using a carbon / sulfur analyzer. This can be confirmed by subtracting the added amount of the water-insoluble conductive carbon material.
- Examples of the metal fluoride metal supported on the oxide include lithium (Li), sodium (Na), magnesium (Mg), calcium (Ca), aluminum (Al), titanium (Ti), vanadium (V), Chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), zirconium (Zr), niobium (Nb), molybdenum (Mo), Examples include tantalum (Ta), tin (Sn), tungsten (W), potassium (K), barium (Ba), and strontium (Sr).
- it is a metal chosen from lithium, sodium, magnesium, calcium, and aluminum from a viewpoint of improving the hydrophobicity of metal fluoride, and improving ion conductivity, and is chosen from lithium and magnesium. More preferably, it is a metal.
- the amount of the metal fluoride supported is determined from the viewpoint of effectively supporting the metal fluoride on the surface of the oxide in which carbon obtained by carbonization of the water-insoluble conductive carbon material and the water-soluble carbon material does not exist.
- the positive electrode active material for a battery it is 0.1 to 5% by mass, preferably 0.2 to 4.5% by mass, more preferably 0.3 to 4% by mass. If the supported amount of the metal fluoride is less than 0.1% by mass, the amount of adsorbed water cannot be sufficiently suppressed, and if the supported amount of the metal fluoride exceeds 5% by mass, details are unknown, Even if the amount of adsorbed moisture is suppressed, the cycle characteristics of the secondary battery may be deteriorated.
- the amount of fluorine present in the positive electrode active material for secondary batteries can be confirmed by an ion analyzer using a solution obtained by acid-dissolving the positive electrode active material for secondary batteries.
- the positive electrode active material for a secondary battery according to the present invention is the above-described efficient while supplementing one or two kinds selected from carbon obtained by carbonizing a water-insoluble conductive carbon material and a water-soluble carbon material with a metal fluoride.
- a metal fluoride represented by (A), (B) or (C)
- an oxide, a water-insoluble conductive carbon material, and a water-soluble carbon material are used.
- 0.1 to 5% by mass of a metal fluoride is supported on a composite containing one or two selected from carbon obtained by carbonizing carbon. Further, from the viewpoint of effectively supporting the metal fluoride on the exposed portion of the oxide surface without the presence of carbon obtained by carbonizing the water-insoluble conductive carbon material and the water-soluble carbon material in the composite, It is preferable that 0.1 to 40 parts by mass of a metal fluoride precursor is added to the composite with respect to 100 parts by mass of the composite and wet mixed to be carried on the composite.
- the positive electrode active material for a secondary battery of the present invention comprises a composite containing an oxide, one or two selected from carbon obtained by carbonizing a water-insoluble conductive carbon material and a water-soluble carbon material, and a composite
- a fired product of a wet mixture of 0.1 to 40 parts by weight of a metal fluoride precursor with respect to 100 parts by weight of the body is preferable.
- the precursor of the metal fluoride is then fired and supported as a metal fluoride, and is present in the positive electrode active material for a secondary battery of the present invention.
- the positive electrode active material for a secondary battery according to the present invention is a positive electrode active material for a secondary battery in which a water-insoluble conductive carbon material and 0.1 to 5% by mass of a metal fluoride are supported on the above oxide (In the case of P-1), specifically, the water-insoluble conductive carbon material is dry-mixed with an oxide obtained by a hydrothermal reaction and then supported on the oxide. More preferably, after being premixed with the oxide, it is mixed while applying a compressive force and a shearing force, and is supported on the oxide.
- the composite containing the oxide and the water-insoluble conductive carbon material includes a lithium compound or a sodium compound, a phosphate compound or a silicate compound, and at least iron.
- a dry mixture of an oxide which is a hydrothermal reaction product of slurry water containing a compound or a manganese compound and a water-insoluble conductive carbon material is preferable.
- supported by the oxide by baking a water-insoluble conductive carbon material is obtained as a composite_body
- a water-soluble carbon material may be added to the composite containing the oxide and the water-insoluble conductive carbon material.
- a water-soluble carbon material may be added to the oxide to obtain a complex with the oxide and then dry-mixed, or a water-soluble carbon material may be added during the dry-mixing.
- the composite obtained at this time contains a water-soluble carbon material together with an oxide and a water-insoluble conductive carbon material.
- the water-soluble carbon material to be supported as carbonized carbon on the composite containing the oxide and the water-insoluble conductive carbon material is such that the water-insoluble conductive carbon material exists in the composite.
- the oxide is supported on the oxide as carbon that is carbonized by being wet-mixed with the composite and then calcined.
- the water-soluble carbon material By firing for carbonizing the water-soluble carbon material, the crystallinity of both the oxide and the water-insoluble conductive carbon material, which have been reduced by dry mixing, can be more effectively recovered. Sexually can be enhanced effectively.
- the water-soluble carbon material the same water-soluble carbon material as that used in the positive electrode active material for secondary battery (P-2) can be used.
- the positive electrode active material (P-1) for a secondary battery of the present invention contains a lithium compound or a sodium compound, a phosphoric acid compound or a silicic acid compound, and a metal salt containing at least an iron compound or a manganese compound.
- a step of adding 0.1 to 40 parts by mass of a metal fluoride precursor, wet mixing and firing (III-1) It is preferable that it is obtained by a manufacturing method provided with.
- a slurry water a containing a lithium compound or sodium compound, a phosphoric acid compound or a silicic acid compound, and a metal salt containing at least an iron compound or a manganese compound is subjected to a hydrothermal reaction to form an oxide X It is the process of obtaining.
- the lithium compound or sodium compound that can be used include hydroxides (for example, LiOH.H 2 O, NaOH), carbonates, sulfates, and acetates. Of these, hydroxide is preferable.
- the content of the lithium compound or silicic acid compound in the slurry water a is preferably 5 to 50 parts by mass, more preferably 7 to 45 parts by mass with respect to 100 parts by mass of water.
- the content of the lithium compound or sodium compound in the slurry water a is preferably 5 to 50 parts by mass with respect to 100 parts by mass of water. More preferably, it is 10 to 45 parts by mass.
- the content of the silicate compound in the slurry water a is preferably 5 to 40 parts by mass, more preferably 7 to 35 parts by mass with respect to 100 parts by mass of water.
- Step (I-1) a lithium compound or a sodium compound is added from the viewpoint of improving the physical properties of the battery by increasing the dispersibility of each component contained in the slurry water a while miniaturizing the obtained positive electrode active material particles.
- the slurry water a obtained in this manner is preferably subjected to a hydrothermal reaction to obtain the oxide X (Ib-1).
- step (I-1) or (Ia-1) it is preferable to stir the mixture A in advance before mixing the phosphoric acid compound or the silicic acid compound with the mixture A.
- the stirring time of the mixture A is preferably 1 to 15 minutes, more preferably 3 to 10 minutes.
- the temperature of the mixture A is preferably 20 to 90 ° C, more preferably 20 to 70 ° C.
- Examples of the phosphoric acid compound used in the step (I-1) or (Ia-1) include orthophosphoric acid (H 3 PO 4 , phosphoric acid), metaphosphoric acid, pyrophosphoric acid, triphosphoric acid, tetraphosphoric acid, ammonium phosphate, Examples include ammonium hydrogen phosphate. Of these, phosphoric acid is preferably used, and an aqueous solution having a concentration of 70 to 90% by mass is preferably used. In the step (I-1) or (Ia-1), when mixing the phosphoric acid into the mixture A, it is preferable to add the phosphoric acid dropwise while stirring the mixture A.
- the dropping rate of phosphoric acid into the mixture A is preferably 15 to 50 mL / min, more preferably 20 to 45 mL / min, and further preferably 28 to 40 mL / min.
- the stirring time of the mixture A while dropping phosphoric acid is preferably 0.5 to 24 hours, and more preferably 3 to 12 hours.
- the stirring speed of the mixture A while dropping phosphoric acid is preferably 200 to 700 rpm, more preferably 250 to 600 rpm, and further preferably 300 to 500 rpm.
- the silicic acid compound used in the step (I-1) or (Ia-1) is not particularly limited as long as it is a reactive silica compound, and amorphous silica, Na 4 SiO 4 (for example, Na 4 SiO 4. H 2 O) and the like.
- the mixture B after mixing the phosphoric acid compound or silicic acid compound preferably contains 2.0 to 4.0 moles of lithium or sodium with respect to 1 mole of phosphoric acid or silicic acid. It is more preferable to contain 1 mol, and the lithium compound or sodium compound and the phosphoric acid compound or silicic acid compound may be used so as to obtain such an amount. More specifically, when a phosphoric acid compound is used in the step (I-1) or (Ia-1), the mixture B after mixing the phosphoric acid compound contains lithium or sodium with respect to 1 mol of phosphoric acid.
- the content is preferably 2.7 to 3.3 mol, more preferably 2.8 to 3.1 mol, and when the silicate compound is used in step (I-1) or (Ia-1),
- the mixture B after mixing the silicic acid compound preferably contains 2.0 to 4.0 moles of lithium, more preferably 2.0 to 3.0 moles per mole of silicic acid. What is necessary is just to use the said lithium compound or sodium compound, and a phosphoric acid compound or a silicic acid compound so that it may become such quantity.
- the reaction in the mixture B is completed, and the oxides represented by the above (A) to (C) A precursor of X is produced in mixture B.
- the precursor of the oxide X represented by the above (A) to (C) exists as fine dispersed particles.
- the precursor of the oxide X is obtained as trilithium phosphate (Li 3 PO 4 ).
- the pressure for purging nitrogen is preferably 0.1 to 0.2 MPa, more preferably 0.1 to 0.15 MPa.
- the temperature of the mixture B after mixing the phosphoric acid compound or silicic acid compound is preferably 20 to 80 ° C., more preferably 20 to 60 ° C.
- the reaction time is preferably 5 to 60 minutes, more preferably 15 to 45 minutes.
- the stirring speed at this time is preferably 200 to 700 rpm, more preferably 250 to 600 rpm.
- the concentration is preferably 0.5 mg / L or less, and more preferably 0.2 mg / L or less.
- a slurry water a containing a precursor of the obtained oxide X and a metal salt containing at least an iron compound or a manganese compound is subjected to a hydrothermal reaction, Oxide X is obtained.
- a metal salt containing at least an iron compound or a manganese compound is added thereto, and a water-soluble carbon material is added if necessary, and the slurry water a and It is preferable to do this. Accordingly, the oxide X represented by the above (A) to (C) can be obtained while simplifying the process, and it is possible to obtain extremely fine particles, which is a very useful secondary battery.
- a positive electrode active material can be obtained.
- iron compounds examples include iron acetate, iron nitrate, and iron sulfate. These may be used alone or in combination of two or more. Among these, iron sulfate is preferable from the viewpoint of improving battery characteristics.
- manganese compounds examples include manganese acetate, manganese nitrate, and manganese sulfate. These may be used alone or in combination of two or more. Among these, manganese sulfate is preferable from the viewpoint of improving battery characteristics.
- the use molar ratio of these manganese compound and iron compound is preferably 99: 1 to 1:99, more preferably 90. : 10 to 10:90.
- the total addition amount of these iron compound and manganese compound is preferably 0.99 to 1.01 mol, more preferably 0.995 with respect to 1 mol of Li 3 PO 4 contained in the slurry water a. ⁇ 1.005 mol.
- metal (M, N, or Q) salts other than an iron compound and a manganese compound as a metal salt as needed.
- M, N, and Q in the metal (M, N, or Q) salt have the same meanings as M, N, and Q in the above formulas (A) to (C), and as the metal salt, sulfate, halogen compound, organic Acid salts and hydrates thereof can be used. These may be used alone or in combination of two or more. Among them, it is more preferable to use a sulfate from the viewpoint of improving battery physical properties.
- the total amount of iron compound, manganese compound, and metal (M, N, or Q) salt is added to the mixture B obtained in the above step (I-1).
- the amount is preferably 0.99 to 1.01 mol, more preferably 0.995 to 1.005 mol, per mol of phosphoric acid or silicic acid.
- the amount of water used for the hydrothermal reaction is phosphoric acid or silicate ions contained in the slurry water a from the viewpoints of solubility of the metal salt used, ease of stirring, synthesis efficiency, and the like.
- the amount is preferably 10 to 50 mol, more preferably 12.5 to 45 mol, relative to 1 mol. More specifically, when the ions contained in the slurry water a are phosphate ions, the amount of water used for the hydrothermal reaction is preferably 10 to 30 mol, more preferably 12 .5 to 25 moles.
- the amount of water used for the hydrothermal reaction is preferably 10 to 50 mol, more preferably 12.5 to 45. Is a mole.
- the order of adding the iron compound, manganese compound and metal (M, N or Q) salt is not particularly limited. Moreover, while adding these metal salts, you may add antioxidant as needed. As such an antioxidant, sodium sulfite (Na 2 SO 3 ), hydrosulfite sodium (Na 2 S 2 O 4 ), aqueous ammonia and the like can be used. From the viewpoint of preventing the formation of the oxide X represented by the above formulas (A) to (C) from being excessively added, the antioxidant is added in an iron compound, a manganese compound. In addition, it is preferably 0.01 to 1 mol, more preferably 0.03 to 0.5 mol, relative to a total of 1 mol of the metal (M, N or Q) salt used as necessary.
- the content of the precursor of the oxide X in the slurry water a obtained by adding an iron compound, a manganese compound, and a metal (M, N or Q) salt or an antioxidant used as necessary is preferably 10. -50% by mass, more preferably 15-45% by mass, and still more preferably 20-40% by mass.
- the hydrothermal reaction in the step (I-1) or (Ib-1) may be 100 ° C. or higher, and preferably 130 to 180 ° C.
- the hydrothermal reaction is preferably carried out in a pressure-resistant vessel.
- the pressure at this time is preferably 0.3 to 0.9 MPa, and the reaction is carried out at 140 to 160 ° C.
- the pressure is preferably 0.3 to 0.6 MPa.
- the hydrothermal reaction time is preferably 0.1 to 48 hours, more preferably 0.2 to 24 hours.
- the obtained oxide X is an oxide represented by the above formulas (A) to (C), which can be isolated by filtration, washing with water, and drying. As the drying means, freeze drying or vacuum drying is used.
- the BET specific surface area of the obtained oxide X is preferably 5 to 40 m 2 / g from the viewpoint of efficiently supporting the water-insoluble conductive carbon material and the metal fluoride and effectively reducing the amount of adsorbed water. More preferably, it is 5 to 20 m 2 / g.
- the BET specific surface area of the oxide X is less than 5 m 2 / g, the primary particles of the positive electrode active material for the secondary battery become too large, and the battery characteristics may be deteriorated.
- the BET specific surface area exceeds 40 m 2 / g, the amount of adsorbed moisture of the positive electrode active material for the secondary battery may increase and affect the battery characteristics.
- Step (II-1) is a step of obtaining the composite A by adding a water-insoluble conductive carbon material to the oxide X obtained in the step (I-1) and dry-mixing.
- a water-insoluble conductive carbon material may be set to the carbon atom equivalent amount of the water-insoluble conductive carbon material in the positive electrode active material for the secondary battery of the present invention.
- the amount is 0.3 to 6.5 parts by mass, more preferably 0.5 to 5.5 parts by mass, and still more preferably 0.6 to 5 parts by mass.
- a water-soluble carbon material may be added and dry-mixed.
- the dry mixing in the step (II-1) is preferably mixing with a normal ball mill, and more preferably, the composite A is obtained by mixing with a planetary ball mill capable of revolving. Further, a water-insoluble conductive carbon material and a water-soluble carbon material used in combination as needed are densely and uniformly dispersed on the surface of the oxide X represented by the above formulas (A) to (C). From the viewpoint of effective loading, it is more preferable to mix the composite A while applying a compressive force and a shearing force to obtain the composite B.
- the process of mixing while applying a compressive force and a shearing force is preferably performed in a closed container equipped with an impeller.
- the peripheral speed of the impeller is preferably 25 to 40 m / s, more preferably 27 from the viewpoint of increasing the tap density of the obtained positive electrode active material and reducing the BET specific surface area to effectively reduce the amount of adsorbed water. ⁇ 40 m / s.
- the mixing time is preferably 5 to 90 minutes, more preferably 10 to 80 minutes.
- the peripheral speed of the impeller means the speed of the outermost end of the rotary stirring blade (impeller), which can be expressed by the following formula (1), and is mixed while applying compressive force and shearing force.
- the processing time and / or the impeller peripheral speed when performing the mixing process while applying the compressive force and the shearing force are appropriately adjusted according to the amount of the composite A charged into the container.
- the container By operating the container, it is possible to perform a process of mixing the mixture while applying a compressive force and a shearing force between the impeller and the inner wall of the container, and the above formulas (A) to (C )
- the water-insoluble conductive carbon material and the water-soluble carbon material used together as necessary are finely and uniformly dispersed on the surface of the oxide X represented by It is possible to obtain a positive electrode active material for a secondary battery that can be reduced significantly.
- a container corresponding to a part capable of accommodating the complex A is preferably 0.1 to 0.7 g, more preferably 0.15 to 0.4 g per 1 cm 3 .
- the apparatus equipped with a closed container that can easily perform mixing while applying compressive force and shear force examples include a high-speed shear mill, a blade-type kneader, and the like. Fine particle composite apparatus Nobilta (manufactured by Hosokawa Micron Corporation) can be suitably used.
- the treatment temperature is preferably 5 to 80 ° C., more preferably 10 to 50 ° C.
- the treatment atmosphere is not particularly limited, but is preferably an inert gas atmosphere or a reducing gas atmosphere.
- step (III-1) 100 parts by mass of the complex is added to the complex A obtained in the step (I-1) (or the complex B when the complex B is obtained in the step (II-1)).
- step (0.1 to 40 parts by mass of a metal fluoride precursor is added and wet-mixed to obtain the composite C, followed by firing.
- the amount of the metal fluoride precursor added is from the viewpoint of effectively supporting the metal fluoride in an amount of 0.1 to 5% by mass on the surface of the oxide X where no water-insoluble conductive carbon material is present.
- the total amount is 0.1 to 40 parts by weight, preferably 0.2 to 36 parts by weight, and more preferably 0.3 to 32 parts by weight with respect to 100 parts by weight.
- water it is preferable to add water together with the metal fluoride precursor.
- the amount of water added is preferably 30 to 300 parts by weight, more preferably 50 to 250 parts by weight, and even more preferably 75 to 200 parts by weight with respect to 100 parts by weight of the complex A (or complex B). It is.
- the metal fluoride precursor may be any compound that can be subsequently fired to form a metal fluoride to be supported on an oxide.
- the metal fluoride precursor is a metal fluoride precursor.
- a fluorine compound and a metal compound which are compounds other than the metal fluoride in combination examples include hydrofluoric acid, ammonium fluoride, and hypofluoric acid. Among them, ammonium fluoride is preferably used.
- metal compound which is a compound other than the metal fluoride examples include metal acetate, metal nitrate, metal lactate, metal oxalate, metal hydroxide, metal ethoxide, metal isopropoxide, metal butoxide and the like. Of these, metal hydroxides are preferred.
- the metal of a metal compound is synonymous with the metal of the said metal fluoride.
- the wet mixing means in step (III-1) is not particularly limited, and can be performed by a conventional method.
- the mixing temperature is preferably 5 to 80 ° C., more preferably 10 to 60 ° C.
- the obtained composite C is preferably dried before firing. Examples of the drying means include spray drying, vacuum drying, freeze drying and the like.
- step (III-1) the composite C obtained by the wet mixing is fired. Firing is preferably performed in a reducing atmosphere or an inert atmosphere.
- the firing temperature is preferably 500 to 800 ° C., more preferably 600 to 770 ° C., from the viewpoint of improving the conductivity by improving the crystallinity of the oxide X and the water-insoluble conductive carbon material that have been lowered by dry mixing or the like. More preferably, it is 650 to 750 ° C.
- the firing time is preferably 10 minutes to 3 hours, more preferably 30 minutes to 1.5 hours.
- the positive electrode active material for a secondary battery according to the present invention is for a secondary battery in which carbon obtained by carbonizing a water-soluble carbon material and 0.1 to 5% by mass of a metal fluoride is supported on the oxide.
- the composite D containing the oxide and the water-soluble carbon material specifically includes a lithium compound or a sodium compound, a phosphate compound or a silicate compound, and at least iron. It is preferably obtained by subjecting slurry water containing a compound or a manganese compound and water-soluble carbon material to a hydrothermal reaction.
- the composite D containing the oxide and the water-soluble carbon material includes a lithium compound or a sodium compound, a phosphoric acid compound or a silicate compound, and at least an iron compound. Or it is preferable that it is a hydrothermal reaction material of the slurry water containing a manganese compound and containing a water-soluble carbon material.
- the positive electrode active material (P-2) for the secondary battery of the present invention contains a lithium compound or a sodium compound, a phosphoric acid compound or a silicic acid compound, and a metal salt containing at least an iron compound or a manganese compound. And subjecting the slurry water b containing the water-soluble carbon material to a hydrothermal reaction to obtain the composite D (I-2), and the obtained composite D to 100 parts by mass of the composite A step of adding 0.1 to 40 parts by mass of a metal fluoride precursor, wet-mixing and firing (II-2) It is preferable that it is obtained by a manufacturing method provided with.
- step (I-2) slurry water b containing a lithium compound or sodium compound, a phosphoric acid compound or a silicic acid compound, and a metal salt containing at least an iron compound or a manganese compound and containing a water-soluble carbon material is treated with water.
- the composite D is obtained by a thermal reaction.
- the lithium compound and sodium compound that can be used, and the content of these in the slurry water b are the same as in step (I-1) in the method for producing the positive electrode active material for secondary battery (P-1).
- the content of the water-soluble carbon material in the slurry water b may be an amount such that the supported amount of the water-soluble carbon material as carbon obtained by carbonization falls within the above range in terms of carbon atoms, as described above.
- the supported amount of the water-soluble carbon material as carbon obtained by carbonization falls within the above range in terms of carbon atoms, as described above.
- the viewpoint of effectively supporting carbon formed by carbonizing a water-soluble carbon material on the surface of the oxide in an amount of 0.1 to 4% by mass, preferably 0.03 with respect to 100 parts by mass of water in the slurry water. To 3.5 parts by mass, more preferably 0.03 to 2.5 parts by mass.
- Step (I-2) from the viewpoint of improving the physical properties of the battery by improving the dispersibility of each component contained in the slurry water b and reducing the particles of the obtained positive electrode active material to improve the battery properties, Step (Ia-2) for obtaining mixture B by mixing phosphoric acid compound or silicic acid compound with mixture A containing, and metal salt and water-soluble carbon material containing at least iron compound or manganese compound in obtained mixture B It is preferable to include the step (Ib-2) of adding the slurry and subjecting the resulting slurry water b to a hydrothermal reaction to obtain the composite D.
- the water-soluble carbon material only needs to be contained in the slurry water b finally subjected to the hydrothermal reaction, and before mixing the phosphate compound or the silicate compound in the step (Ia-2).
- it may be added at the time of mixing, or may be added to the slurry water b by adding it together with a metal salt containing at least an iron compound or a manganese compound in the step (Ib-2).
- a water-soluble carbon material is added together with a metal salt containing an iron compound or a manganese compound in the step (Ib-2). Is preferred.
- step (I-2) or (Ia-2) it is preferable to stir the mixture A in advance before mixing the phosphoric acid compound or the silicic acid compound with the mixture A.
- the stirring time of the mixture A is preferably 1 to 15 minutes, more preferably 3 to 10 minutes.
- the temperature of the mixture A is preferably 20 to 90 ° C, more preferably 20 to 70 ° C.
- the phosphoric acid compound and the silicic acid compound that can be used are the same as those in the step (I-1) or (Ia-1) in the method for producing the positive electrode active material for secondary battery (P-1).
- the mixing method with the mixture A when using phosphoric acid is also the same as in the above step (I-1) or (Ia-1).
- the content of lithium or sodium in the mixture B after mixing the phosphoric acid compound or silicic acid compound is determined by the step (I-1) in the method for producing the positive electrode active material for secondary battery (P-1). Alternatively, it is the same as the mixture B in (Ia-1), and the lithium compound or sodium compound and the phosphoric acid compound or silicic acid compound may be used so as to obtain such an amount.
- the reaction in the mixture B is completed, and the oxides represented by the above (A) to (C) A precursor of X is produced in mixture B.
- nitrogen is purged, the reaction can proceed in a state where the dissolved oxygen concentration in the mixture B is reduced, and the dissolved oxygen concentration in the mixture B containing the precursor of the resulting oxide X is also effective. Therefore, oxidation of iron compounds, manganese compounds, etc. added in the next step can be suppressed.
- the precursor of the oxide X represented by the above (A) to (C) exists as fine dispersed particles.
- the precursor of the oxide X is obtained as trilithium phosphate (Li 3 PO 4 ).
- the pressure at the time of purging nitrogen, the temperature of the mixture B, the reaction time, the stirring speed of the mixture B, and the dissolved oxygen concentration are the same as those in the method for producing the positive electrode active material (P-1) for secondary battery (I- In 1) or (Ia-1), the same applies as the pressure at the time of purging nitrogen, the temperature of the mixture B, the reaction time, the stirring speed of the mixture B, and the dissolved oxygen concentration.
- the obtained mixture B and slurry water b containing a metal salt containing at least an iron compound or a manganese compound and containing a water-soluble carbon material are subjected to a hydrothermal reaction.
- complex D The obtained mixture B was used as a precursor of the oxide X represented by the above (A) to (C), and a metal salt containing at least an iron compound or a manganese compound and a water-soluble carbon material were added thereto.
- the slurry water b is preferably used.
- the use molar ratio of these manganese compound and iron compound is preferably 99: 1 to 1:99, more preferably 90:10 to 10:90.
- the total addition amount of these iron compound and manganese compound is preferably 0.99 to 1.01 mol, more preferably 0.995 with respect to 1 mol of Li 3 PO 4 contained in the slurry water b. ⁇ 1.005 mol.
- the total amount of iron compound, manganese compound and metal (M, N or Q) salt is obtained in the above step (I-2).
- the amount is preferably 0.99 to 1.01 mol, more preferably 0.995 to 1.005 mol, based on 1 mol of phosphoric acid or silicic acid in the resulting mixture.
- the water-soluble carbon material in the slurry water b is preferably 0.03 to 3.4% by mass, and more preferably 0.03 to 2.4% by mass.
- the amount of water used in the hydrothermal reaction, the antioxidant that may be added if necessary, and the amount added are the same as those in the method for producing the positive electrode active material for secondary batteries (P-1). This is similar to the case of obtaining the oxide X in the step (I-1) or (Ib-1).
- the order of addition of the iron compound, manganese compound, metal (M, N or Q) salt, and water-soluble carbon material is not particularly limited.
- the content of the mixture B in the slurry b obtained by adding an iron compound, a manganese compound and a metal (M, N or Q) salt used as required, and a water-soluble carbon material or an antioxidant is preferably It is 10 to 50% by mass, more preferably 15 to 45% by mass, and further preferably 20 to 40% by mass.
- the temperature, pressure, and hydrothermal reaction time of the hydrothermal reaction in the step (I-2) or (Ib-2) are the same as those in the step (I-1) in the method for producing the positive electrode active material for secondary battery (P-1).
- Or (Ib-1) is the same as in the case of obtaining the oxide X.
- the obtained composite D is a composite containing the oxide X represented by the above formulas (A) to (C) and a water-soluble carbon material. After filtration, the composite D is washed with water and dried. It can be isolated as a composite particle. As the drying means, freeze drying or vacuum drying is used.
- the BET specific surface area of the composite D obtained is also the same as that of the oxide X obtained in the step (I-1) or (Ib-1) in the method for producing the positive electrode active material for secondary battery (P-1). It is.
- Step (II-2) is a step in which a metal fluoride precursor is added to the composite D obtained in step (I-2), wet-mixed, and fired.
- a metal fluoride precursor is added to the composite D obtained in step (I-2), wet-mixed, and fired.
- the addition amount of the metal fluoride precursor and the addition amount of water with respect to 100 parts by mass of the composite D are the composite A in the step (III-1) in the method for producing the positive electrode active material for secondary battery (P-1).
- (Or Composite B) The same as the addition amount of the metal fluoride precursor and the addition amount of water with respect to 100 parts by mass.
- the wet mixing means in the step (II-2) and the firing conditions of the mixture obtained by the wet mixing are also described in the step (III-) in the method for producing the positive electrode active material for secondary battery (P-1).
- the wet mixing means in 1) and the firing conditions of the mixture obtained by such wet mixing are the same.
- the positive electrode active material for a secondary battery of the present invention one or two kinds selected from carbon obtained by carbonizing the water-insoluble conductive carbon material and the water-soluble carbon material and the metal fluoride are both converted into the oxide. It is supported and acts synergistically, and the amount of adsorbed moisture in the positive electrode active material for the secondary battery can be effectively reduced. Specifically, the amount of adsorbed moisture of the positive electrode active material for secondary battery of the present invention is the same for the secondary battery in the case of the positive electrode active material for secondary battery in which the oxide is represented by the above formula (A) or (C).
- the positive electrode active material preferably it is 1200 ppm or less, more preferably 1000 ppm or less, and in the positive electrode active material for a secondary battery in which the oxide is represented by the above formula (B), preferably 2500 ppm or less, and more Preferably it is 2000 ppm or less.
- the amount of adsorbed moisture is such that moisture is adsorbed until equilibrium is reached at a temperature of 20 ° C. and a relative humidity of 50%, the temperature is raised to 150 ° C. and held for 20 minutes, and further raised to a temperature of 250 ° C. Measured as the amount of water volatilized from the start point to the end point, starting from when the temperature rise is resumed from 150 ° C.
- the amount of adsorbed moisture of the positive electrode active material for a secondary battery and the amount of moisture volatilized from the start point to the end point are the same, and the measured value of the volatilized moisture amount is This is the amount of moisture adsorbed on the positive electrode active material for the secondary battery.
- the positive electrode active material for a secondary battery of the present invention hardly adsorbs moisture, the amount of adsorbed moisture can be effectively reduced without requiring strong drying conditions as a production environment, and the resulting lithium In both the ion secondary battery and the sodium ion secondary battery, it is possible to stably exhibit excellent battery characteristics even under various usage environments.
- the tap density of the positive electrode active material for a secondary battery of the present invention is preferably 0.5 to 1.6 g / cm 3 , more preferably 0.8 from the viewpoint of effectively reducing the amount of adsorbed moisture. ⁇ 1.6 g / cm 3 .
- the BET specific surface area of the positive electrode active material for a secondary battery of the present invention is preferably 5 to 21 m 2 / g, more preferably 7 to 20 m 2 / g, from the viewpoint of effectively reducing the amount of adsorbed moisture. It is.
- the secondary battery to which the positive electrode for the secondary battery including the positive electrode active material for the secondary battery of the present invention can be applied is not particularly limited as long as the positive electrode, the negative electrode, the electrolytic solution, and the separator are essential components.
- the material configuration is not particularly limited, and those having a known material configuration can be used.
- a carbon material such as lithium metal, sodium metal, graphite, or amorphous carbon. It is preferable to use an electrode formed of an intercalating material capable of electrochemically inserting and extracting lithium ions or sodium ions, particularly a carbon material.
- the electrolytic solution is obtained by dissolving a supporting salt in an organic solvent.
- the organic solvent is not particularly limited as long as it is an organic solvent that is usually used for an electrolyte solution of a lithium ion secondary battery or a sodium ion secondary battery.
- carbonates, halogenated hydrocarbons, ethers, ketones Nitriles, lactones, oxolane compounds and the like can be used.
- the type of the supporting salt is not particularly limited, but in the case of a lithium ion secondary battery, an inorganic salt selected from LiPF 6 , LiBF 4 , LiClO 4 , LiAsF 6 , a derivative of the inorganic salt, LiSO 3 CF 3 , an organic material selected from LiC (SO 3 CF 3 ) 2 , LiN (SO 3 CF 3 ) 2 , LiN (SO 2 C 2 F 5 ) 2 and LiN (SO 2 CF 3 ) (SO 2 C 4 F 9 ) It is preferably at least one of a salt and a derivative of the organic salt.
- an inorganic salt selected from NaPF 6 , NaBF 4 , NaClO 4 and NaAsF 6 a derivative of the inorganic salt, NaSO 3 CF 3 , NaC (SO 3 CF 3 ) 2 and NaN (SO 3 CF 3 ) 2 , NaN (SO 2 C 2 F 5 ) 2, and an organic salt selected from NaN (SO 2 CF 3 ) (SO 2 C 4 F 9 ), and at least one derivative of the organic salt It is preferable.
- the separator plays a role of electrically insulating the positive electrode and the negative electrode and holding the electrolytic solution.
- a porous synthetic resin film particularly a polyolefin polymer (polyethylene, polypropylene) porous film may be used.
- Example 1-1 4.9 kg of LiOH.H 2 O and 11.7 L of ultrapure water were mixed to obtain slurry water. Then, with stirring for 30 minutes at speed 400rpm while maintaining the resulting slurry water temperature of 25 ° C., a 70% aqueous solution of phosphoric acid 5.09kg was added dropwise at 35 mL / min, to obtain a mixture A 11 .
- the pH of the mixed slurry was 10.0 and contained 0.33 mol of phosphoric acid with respect to 1 mol of lithium.
- the obtained mixture A 11 was purged with nitrogen while stirring at a speed of 400 pm for 30 minutes to complete the reaction with the mixture A 11 (dissolved oxygen concentration 0.5 mg / L).
- 1.63 kg of FeSO 4 .7H 2 O and 5.60 kg of MnSO 4 .H 2 O were added to 21.7 kg of the mixture A 11, and 46.8 g of Na 2 SO 3 was further added to the mixture at a speed of 400 rpm. stirring and mixing to at obtain a slurry water a 11.
- the added FeSO 4 ⁇ 7H 2 O and MnSO 4 ⁇ H 2 O molar ratio of (FeSO 4 ⁇ 7H 2 O: MnSO 4 ⁇ H 2 O) is 20: was 80.
- the slurry water a 11 poured into the synthesis vessel installed in a steam-heated autoclave.
- the mixture was heated with stirring at 170 ° C. for 1 hour using saturated steam obtained by heating water (dissolved oxygen concentration less than 0.5 mg / L) with a membrane separator.
- the pressure in the autoclave was 0.8 MPa.
- the produced crystal was filtered, and then washed with 12 parts by mass of water with respect to 1 part by mass of the crystal.
- the washed crystal was vacuum-dried under the conditions of 60 ° C. and 1 Torr, oxide (powder, chemical composition represented by the formula (A): LiFe 0.2 Mn 0.8 PO 4 , BET specific surface area 21 m 2 / g, average particle size 60 nm. )
- Example 1-2 0.59 g of ammonium fluoride to be added to the composite B 11 (corresponding to 1.0% by mass in terms of LiF in the positive electrode active material for a lithium ion secondary battery), and LiOH.H for adjusting the solution B
- Example 1-3 1.47 g of ammonium fluoride added to the composite B 11 (corresponding to 2.5% by mass in terms of LiF in the positive electrode active material for a lithium ion secondary battery), and LiOH.H for adjusting the solution B
- Example 1-4 0.59 g of ammonium fluoride to be added to the composite B 11 (corresponding to 0.5% by mass in terms of MgF 2 in the positive electrode active material for a lithium ion secondary battery), and LiOH • for adjusting the solution B
- a positive electrode active material for a lithium ion secondary battery LiFe 0.2 Mn 0.8 PO 4 , carbonic acid
- 0.69 g of magnesium acetate tetrahydrate was used instead of H 2 O.
- Amount 1.6% by mass
- MgF 2 amount 0.5% by mass).
- Example 1-5 1.18 g of ammonium fluoride to be added to the composite B 11 (corresponding to 1.0% by mass in terms of MgF 2 in the positive electrode active material for a lithium ion secondary battery), and LiOH for adjusting the solution B
- a positive electrode active material for a lithium ion secondary battery LiFe 0.2 Mn 0.8 PO 4 , carbonic acid
- Amount 1.6% by mass
- amount of MgF 2 1.0% by mass).
- Example 1-1 A lithium ion secondary was prepared in the same manner as in Example 1-1 except that 50 mL of water was added to the obtained composite B 11 and solution B was prepared without using ammonium fluoride and LiOH ⁇ H 2 O.
- Example 2-1 3.75 L of ultrapure water was mixed with 0.428 kg of LiOH.H 2 O and 1.40 kg of Na 4 SiO 4 .nH 2 O to obtain slurry water. Next, 0.39 kg of FeSO 4 .7H 2 O, 0.79 kg of MnSO 4 .5H 2 O and 53 g of Zr (SO 4 ) 2 .4H 2 O were added to the obtained slurry water, and the temperature was adjusted to 25 ° C. It was stirred for 30 minutes at speed 400rpm while maintaining, to obtain a slurry water a 21.
- the molar ratio of FeSO 4 .7H 2 O, MnSO 4 .5H 2 O and Zr (SO 4 ) 2 .4H 2 O added was 28: 66: 3.
- the obtained slurry water a 21 was charged into a synthesis container installed in a steam heating autoclave. After the addition, the mixture was heated with stirring at 150 ° C. for 12 hours using saturated steam obtained by heating water (dissolved oxygen concentration less than 0.5 mg / L) with a membrane separator. The pressure in the autoclave was 0.4 MPa.
- the produced crystal was filtered, and then washed with 12 parts by mass of water with respect to 1 part by mass of the crystal.
- the washed crystals were freeze-dried at ⁇ 50 ° C. for 12 hours to obtain oxides (powder, chemical composition represented by the formula (B): Li 2 Fe 0.28 Mn 0.66 Zr 0.03 SiO 4 , BET specific surface area 35 m 2 / g, average A particle size of 50 nm) was obtained.
- Example 2-3 0.132 g of LiOH and 0.118 g of ammonium fluoride to be added to the composite B 21 (corresponding to 2.0% by mass in terms of the amount of LiF supported in 100% by mass of the positive electrode active material for a lithium ion secondary battery)
- the amount of AlF 3 2.0 mass%).
- Example 2-5 Instead of LiOH added to the composite B 21 , 0.277 g of Mg (CH 3 COO) 2 .4H 2 O and 0.236 g of ammonium fluoride (in terms of the amount of MgF 2 supported in the positive electrode active material for a lithium ion secondary battery)
- Example 3-1 A solution was obtained by mixing 0.60 kg of NaOH and 9.0 L of water. Next, the obtained solution is stirred for 5 minutes while maintaining the temperature at 25 ° C., and 0.577 kg of 85% phosphoric acid aqueous solution is dropped at 35 mL / min, followed by stirring at a speed of 400 rpm for 12 hours. gave a slurry containing a mixture B 31. Such a slurry contained 3.00 moles of sodium per mole of phosphorus. The obtained slurry was purged with nitrogen gas to adjust the dissolved oxygen concentration to 0.5 mg / L, then 0.139 kg of FeSO 4 .7H 2 O, 0.964 kg of MnSO 4 .5H 2 O, MgSO 4.
- oxide X 31 (powder, chemical composition represented by the formula (C): NaFe 0.1 Mn 0.8 Mg 0.1 PO 4 , BET specific surface area 15 m 2 / g, average A particle size of 100 nm) was obtained.
- Example 3-4 Instead of LiOH to be added to the composite B 31 , 0.078 g of Al (OH) 3 and 0.353 g of ammonium fluoride (2.0 mass in terms of the amount of AlF 3 supported in the positive electrode active material for sodium ion secondary battery)
- Example 3-5 Instead of LiOH added to the composite B 31 , 0.277 g of Mg (CH 3 COO) 2 .4H 2 O and 0.236 g of ammonium fluoride (in terms of supported amount of MgF 3 in the positive electrode active material for sodium ion secondary battery)
- the amount of MgF 3 2.0 mass%).
- Example 4-1 12.72 g of LiOH.H 2 O and 90 mL of water were mixed to obtain a mixture A 41 (slurry water). Next, 11.53 g of 85% aqueous phosphoric acid solution was added dropwise at 35 mL / min while stirring the resulting mixture A 41 at a temperature of 25 ° C. for 5 minutes, followed by 12 hours at 400 rpm under a nitrogen gas purge. To obtain a mixture B 41 (slurry water, dissolved oxygen concentration 0.5 mg / L). Such mixtures B 41, compared per mole of phosphorus and contained lithium 2.97 mol.
- the resulting slurry water b 41 were placed in a synthetic vessel installed in a steam-heated autoclave. After the addition, the mixture was heated with stirring at 170 ° C. for 1 hour using saturated steam obtained by heating water (dissolved oxygen concentration less than 0.5 mg / L) with a membrane separator. The pressure in the autoclave was 0.8 MPa. The produced crystal was filtered, and then washed with 12 parts by mass of water with respect to 1 part by mass of the crystal. The washed crystals were freeze-dried at ⁇ 50 ° C.
- Example 4-4 Instead of LiOH added to the composite D 41 , 0.078 g of Al (OH) 3 and 0.353 g of ammonium fluoride (2.0 in terms of the amount of AlF 3 supported in the positive electrode active material for a lithium ion secondary battery)
- Example 5-1 LiOH ⁇ H 2 O 4.28g, was obtained Na 4 SiO 4 ⁇ nH 2 O 13.97g in a mixture of ultra-pure water 37.5mL mixture B 51 (slurry water, dissolved oxygen concentration 0.5 mg / L) of .
- B 51 slurry water, dissolved oxygen concentration 0.5 mg / L
- To this mixture B 51 3.92 g of FeSO 4 .7H 2 O, 7.93 g of MnSO 4 .5H 2 O, and 0.53 g of Zr (SO 4 ) 2 .4H 2 O are added and maintained at a temperature of 25 ° C. It was stirred for 30 minutes at speed 400rpm while to obtain a slurry water b 51.
- the molar ratio of FeSO 4 .7H 2 O, MnSO 4 .5H 2 O and Zr (SO 4 ) 2 .4H 2 O added was 28: 66: 3.
- the resulting slurry water b 51 were placed in a synthetic vessel installed in a steam-heated autoclave. After the addition, the mixture was heated with stirring at 150 ° C. for 12 hours using saturated steam obtained by heating water (dissolved oxygen concentration less than 0.5 mg / L) with a membrane separator. The pressure in the autoclave was 0.4 MPa.
- the produced crystal was filtered, and then washed with 12 parts by mass of water with respect to 1 part by mass of the crystal.
- the washed crystals were freeze-dried at ⁇ 50 ° C. for 12 hours to give a composite D 51 (powder, chemical composition of the oxide represented by the formula (B): Li 2 Fe 0.28 Mn 0.66 Zr 0.03 SiO 4 , BET specific surface area of 35 m. 2 / g, average particle size 50 nm).
- Li 2 Fe 0.28 Mn 0.66 Zr 0.03 SiO 4 positive electrode active material for a lithium ion secondary battery
- Example 6-1 A solution was obtained by mixing 6.00 g of NaOH and 90 mL of water. The resulting solution is then stirred for 5 minutes while maintaining the temperature at 25 ° C., and 5.77 g of 85% aqueous phosphoric acid solution is added dropwise at 35 mL / min, followed by stirring at a speed of 400 rpm for 12 hours. As a result, a mixture B 61 (slurry water) was obtained. Such mixtures B 61, compared per mole of phosphorus and contained sodium 3.00 mol.
- the obtained mixture B 61 was purged with nitrogen gas to adjust the dissolved oxygen concentration to 0.5 mg / L, then 1.39 g of FeSO 4 .7H 2 O, 9.64 g of MnSO 4 .5H 2 O, MgSO 4 ⁇ 7H 2 O 1.24g, and glucose 0.59 g (corresponding to 1.4 wt% in terms of carbon atoms content in the sodium ion secondary battery positive electrode active material in) was added to obtain a slurry water b 61 .
- the molar ratio of added FeSO 4 .7H 2 O, MnSO 4 .5H 2 O and MgSO 4 .7H 2 O is 10:80:10.
- the obtained slurry water b 61 was put into a synthesis vessel purged with nitrogen gas installed in a steam heating autoclave. After the addition, the mixture was heated with stirring at 200 ° C. for 3 hours using saturated steam obtained by heating water (dissolved oxygen concentration less than 0.5 mg / L) with a membrane separator. The pressure in the autoclave was 1.4 MPa.
- the produced crystal was filtered, and then washed with 12 parts by mass of water with respect to 1 part by mass of the crystal.
- the washed crystal was freeze-dried at ⁇ 50 ° C. for 12 hours to give a composite D 61 (chemical composition of an oxide represented by the formula (C): NaFe 0.1 Mn 0.8 Mg 0.1 PO 4 , BET specific surface area 15 m 2 / g, An average particle size of 100 nm) was obtained.
- Example 6-4 Instead of LiOH added to the composite D 61 , 0.078 g of Al (OH) 3 and 0.353 g of ammonium fluoride (2.0 in terms of the amount of AlF 3 supported in the positive electrode active material for a sodium ion secondary battery)
- the amount of adsorbed moisture of each positive electrode active material obtained in Examples 1-1 to 6-5 and Comparative Examples 1-1 to 6-2 was measured according to the following method.
- About the positive electrode active material (composite particle) after allowing it to stand for 1 day in an environment of a temperature of 20 ° C. and a relative humidity of 50% and adsorbing moisture until reaching equilibrium, raising the temperature to 150 ° C. and holding for 20 minutes, Furthermore, when the temperature is raised to 250 ° C. and held for 20 minutes, the start point is when the temperature rise is resumed from 150 ° C., and the end point is when the constant temperature state at 250 ° C. is finished.
- the amount of water that volatilized was measured with a Karl Fischer moisture meter (MKC-610, manufactured by Kyoto Electronics Industry Co., Ltd.) and determined as the amount of water adsorbed on the positive electrode active material. The results are shown in Tables 1 and 2.
- LiPF 6 in the case of a lithium ion secondary battery
- NaPF 6 in the case of a sodium ion secondary battery
- a known one such as a polymer porous film such as polypropylene was used.
- These battery components were assembled and housed in a conventional manner in an atmosphere having a dew point of ⁇ 50 ° C. or lower to produce a coin-type secondary battery (CR-2032).
- a charge / discharge test was performed using the manufactured coin-type secondary battery.
- the charging condition is a constant current and constant voltage charge with a current of 1 CA (330 mA / g) and a voltage of 4.5 V
- the discharge condition is 1 CA (330 mA / g)
- a constant current discharge with a final voltage of 1.5 V As a result, the discharge capacity at 1 CA was obtained.
- the charging conditions are a constant current and constant voltage charging with a current of 1 CA (154 mA / g) and a voltage of 4.5 V
- the discharging conditions are a constant current discharge of 1 CA (154 mA / g) and a final voltage of 2.0 V.
- the discharge capacity at 1 CA was obtained.
- the positive electrode active material of the example can surely reduce the amount of adsorbed moisture as compared with the positive electrode active material of the comparative example, and can also exhibit excellent performance in the obtained battery.
Abstract
Description
例えば、特許文献4には、マリサイト型NaMnPO4を用いたナトリウムイオン二次電池用活物質が開示されており、また特許文献5には、オリビン型構造を有するリン酸遷移金属ナトリウムを含む正極活物質が開示されており、いずれの文献においても高性能なナトリウムイオン二次電池が得られることを示している。
LiFeaMnbMcPO4・・・(A)
(式(A)中、MはMg、Ca、Sr、Y、Zr、Mo、Ba、Pb、Bi、La、Ce、Nd又はGdを示す。a、b及びcは、0≦a≦1、0≦b≦1、0≦c≦0.2、及び2a+2b+(Mの価数)×c=2を満たし、かつa+b≠0を満たす数を示す。)
Li2FedMneNfSiO4・・・(B)
(式(B)中、NはNi、Co、Al、Zn、V又はZrを示す。d、e及びfは、0≦d≦1、0≦e≦1、及び0≦f<1、2d+2e+(Nの価数)×f=2を満たし、かつd+e≠0を満たす数を示す。)
NaFegMnhQiPO4・・・(C)
(式(C)中、QはMg、Ca、Co、Sr、Y、Zr、Mo、Ba、Pb、Bi、La、Ce、Nd又はGdを示す。g、h及びiは、0≦g≦1、0≦h≦1、0≦i<1、及び2g+2h+(Qの価数)×i=2を満たし、かつg+h≠0を満たす数を示す。)
で表される酸化物に、水不溶性導電性炭素材料及び水溶性炭素材料が炭化されてなる炭素から選ばれる1種又は2種と、0.1~5質量%の金属フッ化物とが担持されてなる二次電池用正極活物質を提供するものである。
得られた酸化物Xに水不溶性導電性炭素材料を添加して乾式混合し、複合体Aを得る工程(II-1)、並びに
得られた複合体Aに、複合体100質量部に対して0.1~40質量部の金属フッ化物の前駆体を添加して湿式混合し、焼成する工程(III-1)
を備える、上記二次電池用正極活物質の製造方法を提供するものである。
得られた複合体Dに、複合体100質量部に対して0.1~40質量部の金属フッ化物金属フッ化物の前駆体を添加して湿式混合し、焼成する工程(II-2)
を備える、二次電池用正極活物質の製造方法を提供するものである。
本発明で用いる酸化物は、少なくとも鉄又はマンガンを含み、かつ下記式(A)、(B)又は(C):
LiFeaMnbMcPO4・・・(A)
(式(A)中、MはMg、Ca、Sr、Y、Zr、Mo、Ba、Pb、Bi、La、Ce、Nd又はGdを示す。a、b及びcは、0≦a≦1、0≦b≦1、0≦c≦0.2、及び2a+2b+(Mの価数)×c=2を満たし、かつa+b≠0を満たす数を示す。)
Li2FedMneNfSiO4・・・(B)
(式(B)中、NはNi、Co、Al、Zn、V又はZrを示す。d、e及びfは、0≦d≦1、0≦e≦1、0≦f<1、及び2d+2e+(Nの価数)×f=2を満たし、かつd+e≠0を満たす数を示す。)
NaFegMnhQiPO4・・・(C)
(式(C)中、QはMg、Ca、Co、Sr、Y、Zr、Mo、Ba、Pb、Bi、La、Ce、Nd又はGdを示す。g、h及びiは、0≦g≦1、0≦h≦1、0≦i<1、及び2g+2h+(Qの価数)×i=2を満たし、かつg+h≠0を満たす数を示す。)
のいずれかの式で表される。
これらの酸化物は、いずれもオリビン型構造を有しており、少なくとも鉄又はマンガンを含む。上記式(A)又は式(B)で表される酸化物を用いた場合には、リチウムイオン電池用正極活物質が得られ、上記式(C)で表される酸化物を用いた場合には、ナトリウムイオン電池用正極活物質が得られる。
すなわち、本発明の二次電池用正極活物質としては、具体的には、例えば、上記酸化物に、水不溶性導電性炭素材料と、0.1~5質量%の金属フッ化物とが担持されてなる二次電池用正極活物質(P-1)、及び上記酸化物に、水溶性炭素材料が炭化されてなる炭素と、0.1~5質量%の金属フッ化物とが担持されてなる二次電池用正極活物質(P-2)が挙げられる。なお、上記二次電池用正極活物質(P-1)は、必要に応じて、さらに上記酸化物に水溶性炭素材料が炭化されてなる炭素が担持されてなるものであってもよい。
また、金属フッ化物は、上記複合体において、水不溶性導電性炭素材料及び水溶性炭素材料が炭化されてなる炭素が存在することなく酸化物表面が露出した部位に有効に担持させる観点から、上記複合体に、複合体100質量部に対して0.1~40質量部の金属フッ化物の前駆体を添加して湿式混合されて複合体に担持されてなるのが好ましい。すなわち、本発明の二次電池用正極活物質は、酸化物と水不溶性導電性炭素材料及び水溶性炭素材料が炭化されてなる炭素から選ばれる1種又は2種とを含む複合体と、複合体100質量部に対して0.1~40質量部の金属フッ化物の前駆体との湿式混合物の焼成物であるのが好ましい。具体的には、かかる金属フッ化物の前駆体は、その後焼成されて、金属フッ化物として担持され、本発明の二次電池用正極活物質に存在することとなる。
上記酸化物と水不溶性導電性炭素材料とを含む複合体に、炭化された炭素として担持されてなることとなる水溶性炭素材料は、かかる複合体において、水不溶性導電性炭素材料が存在することなく酸化物表面が露出した部位に、さらに炭素を有効に担持させる観点から、上記複合体と湿式混合された後、焼成されることにより炭化されてなる炭素として酸化物に担持されてなるものであるのが好ましい。この水溶性炭素材料を炭化するための焼成により、乾式混合等により低下した酸化物及び水不溶性導電性炭素材料双方の結晶性をさらに有効に回復させることができるため、得られる正極活物質における導電性を有効に高めることができる。
なお、ここで水溶性炭素材料としては、二次電池用正極活物質(P-2)において用い得る上記水溶性炭素材料と同様のものを用いることができる。
得られた酸化物Xに水不溶性導電性炭素材料を添加して乾式混合し、複合体Aを得る工程(II-1)、並びに
得られた複合体Aに、複合体100質量部に対して0.1~40質量部の金属フッ化物の前駆体を添加して湿式混合し、焼成する工程(III-1)
を備える製造方法により得られるものであるのが好ましい。
用い得るリチウム化合物又はナトリウム化合物としては、水酸化物(例えばLiOH・H2O、NaOH)、炭酸化物、硫酸化物、酢酸化物が挙げられる。なかでも、水酸化物が好ましい。
スラリー水aにおけるリチウム化合物又はケイ酸化合物の含有量は、水100質量部に対し、好ましくは5~50質量部であり、より好ましくは7~45質量部である。より具体的には、工程(I-1)においてリン酸化合物を用いた場合、スラリー水aにおけるリチウム化合物又はナトリウム化合物の含有量は、水100質量部に対し、好ましくは5~50質量部であり、より好ましくは10~45質量部である。また、ケイ酸化合物を用いた場合、スラリー水aにおけるケイ酸化合物の含有量は、水100質量部に対し、好ましくは5~40質量部であり、より好ましくは7~35質量部である。
なお、混合物Aを撹拌する際、さらに混合物Aの沸点温度以下に冷却するのが好ましい。具体的には、80℃以下に冷却するのが好ましく、20~60℃に冷却するのがより好ましい。
このような量となるよう、上記リチウム化合物又はナトリウム化合物と、リン酸化合物又はケイ酸化合物を用いればよい。
また、窒素をパージする際、反応を良好に進行させる観点から、リン酸化合物又はケイ酸化合物を混合した後の混合物Bを撹拌するのが好ましい。このときの撹拌速度は、好ましくは200~700rpmであり、より好ましくは250~600rpmである。
得られた酸化物Xの前駆体を混合物のまま用い、これに少なくとも鉄化合物又はマンガン化合物を含む金属塩を添加して、また必要に応じて水溶性炭素材料を添加して、スラリー水aとするのが好ましい。これにより、工程を簡略化させつつ、上記(A)~(C)で表される酸化物Xを得ることができるとともに、極めて微細な粒子とすることが可能となり、非常に有用な二次電池用正極活物質を得ることができる。
これら金属(M、N又はQ)塩を用いる場合、鉄化合物、マンガン化合物、及び金属(M、N又はQ)塩の合計添加量は、上記工程(I-1)において得られた混合物B中のリン酸又はケイ酸1モルに対し、好ましくは0.99~1.01モルであり、より好ましくは0.995~1.005モルである。
得られた酸化物Xは、上記式(A)~(C)で表される酸化物であり、ろ過後、水で洗浄し、乾燥することによりこれを単離できる。なお、乾燥手段は、凍結乾燥、真空乾燥が用いられる。
なお、インペラの周速度とは、回転式攪拌翼(インペラ)の最外端部の速度を意味し、下記式(1)により表すことができ、また圧縮力及びせん断力を付加しながら混合する処理を行う時間は、インペラの周速度が遅いほど長くなるように、インペラの周速度によっても変動し得る。
インペラの周速度(m/s)=
インペラの半径(m)×2×π×回転数(rpm)÷60・・・(1)
例えば、上記混合する処理を、周速度25~40m/sで回転するインペラを備える密閉容器内で6~90分間行う場合、容器に投入する複合体Aの量は、有効容器(インペラを備える密閉容器のうち、複合体Aを収容可能な部位に相当する容器)1cm3当たり、好ましくは0.1~0.7gであり、より好ましくは0.15~0.4gである。
上記混合の処理条件としては、処理温度が、好ましくは5~80℃、より好ましくは10~50℃である。処理雰囲気としては、特に限定されないが、不活性ガス雰囲気下、又は還元ガス雰囲気下が好ましい。
得られた複合体Dに、複合体100質量部に対して0.1~40質量部の金属フッ化物の前駆体を添加して湿式混合し、焼成する工程(II-2)
を備える製造方法により得られるものであるのが好ましい。
用い得るリチウム化合物及びナトリウム化合物、並びにこれらのスラリー水bにおける含有量は、上記二次電池用正極活物質(P-1)の製造方法での工程(I-1)と同様である。
この際、水溶性炭素材料は、最終的に水熱反応に付されるスラリー水b中に含まれていればよく、工程(Ia-2)において、リン酸化合物又はケイ酸化合物を混合する前又は混合時に添加してもよく、或いは工程(Ib-2)において少なくとも鉄化合物又はマンガン化合物を含む金属塩とともに添加することによりスラリー水bとしてもよい。なかでも、上記酸化物に水溶性炭素材料が炭化されてなる炭素を効率的に担持させる観点から、工程(Ib-2)において鉄化合物又はマンガン化合物を含む金属塩とともに水溶性炭素材料を添加するのが好ましい。
用い得るリン酸化合物及びケイ酸化合物は、上記二次電池用正極活物質(P-1)の製造方法での工程(I-1)又は(Ia-1)と同様であり、リン酸化合物としてリン酸を用いる際の混合物Aとの混合方法についても、上記工程(I-1)又は(Ia-1)と同様である。
また、リン酸化合物又はケイ酸化合物を混合した後の混合物B中におけるリチウム又はナトリウムの含有量は、上記二次電池用正極活物質(P-1)の製造方法での工程(I-1)又は(Ia-1)における混合物Bと同様であり、そのような量となるよう、上記リチウム化合物又はナトリウム化合物と、リン酸化合物又はケイ酸化合物を用いればよい。
窒素をパージする際における圧力、混合物Bの温度、反応時間、混合物Bの撹拌速度、及び溶存酸素濃度は、上記二次電池用正極活物質(P-1)の製造方法での工程(I-1)又は(Ia-1)における、窒素をパージする際における圧力、混合物Bの温度、反応時間、混合物Bの撹拌速度、及び溶存酸素濃度と同様である。
得られた混合物Bを、上記(A)~(C)で表される酸化物Xの前駆体として用い、これに少なくとも鉄化合物又はマンガン化合物を含む金属塩、及び水溶性炭素材料を添加して、スラリー水bとして用いるのが好ましい。これにより、工程を簡略化させつつ、上記(A)~(C)で表される酸化物Xに効率的に水溶性炭素材料が炭化してなる炭素を担持させることができるとともに、極めて微細な粒子とすることが可能となり、非常に有用な二次電池用正極活物質を得ることができる。
用い得る鉄化合物、マンガン化合物、並びに鉄化合物及びマンガン化合物以外の金属(M、N又はQ)塩は、上記二次電池用正極活物質(P-1)の製造方法での工程(I-1)又は(Ib-1)において酸化物Xを得る場合と同様である。
また、必要に応じて金属(M、N又はQ)塩を用いる場合、鉄化合物、マンガン化合物、及び金属(M、N又はQ)塩の合計添加量は、上記工程(I-2)において得られた混合物中のリン酸又はケイ酸1モルに対し、好ましくは0.99~1.01モルであり、より好ましくは0.995~1.005モルである。
このように、本発明の二次電池用正極活物質は、水分を吸着しにくいため、製造環境として強い乾燥条件を必要とすることなく吸着水分量を有効に低減することができ、得られるリチウムイオン二次電池及びナトリウムイオン二次電池の双方において、様々な使用環境下でも優れた電池特性を安定して発現することが可能となる。
なお、温度20℃及び相対湿度50%にて平衡に達するまで水分を吸着させ、温度150℃まで昇温して20分間保持した後、さらに温度250℃まで昇温して20分間保持したときの、150℃から昇温を再開するときを始点、及び250℃での恒温状態を終えたときを終点とする、始点から終点までの間に揮発した水分量は、例えばカールフィッシャー水分計を用いて測定することができる。
LiOH・H2O 4.9kg、及び超純水11.7Lを混合してスラリー水を得た。次いで、得られたスラリー水を25℃の温度に保持しながら速度400rpmにて30分間撹拌しつつ、70%のリン酸水溶液 5.09kgを35mL/minで滴下して、混合物A11を得た。かかる混合スラリー液のpHは10.0であり、リチウム1モルに対し、0.33モルのリン酸を含有していた。
次いで、スラリー水a11を蒸気加熱式オートクレーブ内に設置した合成容器に投入した。投入後、隔膜分離装置により水(溶存酸素濃度0.5mg/L未満)を加熱して得た飽和蒸気を用いて、170℃で1時間攪拌しながら加熱した。オートクレーブ内の圧力は、0.8MPaであった。生成した結晶をろ過し、次いで結晶1質量部に対し、12質量部の水により洗浄した。洗浄した結晶を60℃、1Torrの条件で真空乾燥し、酸化物(粉末、式(A)で表される化学組成:LiFe0.2Mn0.8PO4、BET比表面積21m2/g、平均粒径60nm)を得た。
複合体B11に添加するフッ化アンモニウムを0.59g(リチウムイオン二次電池用正極活物質中におけるLiF換算量で1.0質量%に相当)、及び溶液Bを調整するためのLiOH・H2Oを0.66gとした以外、実施例1-1と同様の方法でリチウムイオン二次電池用正極活物質(LiFe0.2Mn0.8PO4、炭素の量=1.6質量%、LiFの量=1.0質量%)を得た。
複合体B11に添加するフッ化アンモニウムを1.47g(リチウムイオン二次電池用正極活物質中におけるLiF換算量で2.5質量%に相当)、及び溶液Bを調整するためのLiOH・H2Oを1.65gとした以外、実施例1-1と同様の方法でリチウムイオン二次電池用正極活物質(LiFe0.2Mn0.8PO4、炭素の量=1.6質量%、LiFの量=2.5質量%)を得た。
複合体B11に添加するフッ化アンモニウムを0.59g(リチウムイオン二次電池用正極活物質中におけるMgF2換算量で0.5質量%に相当)、及び溶液Bを調整するためのLiOH・H2Oの代わりに、酢酸マグネシウム四水和物 0.69gを用いた以外、実施例1-1と同様の方法でリチウムイオン二次電池用正極活物質(LiFe0.2Mn0.8PO4、炭素の量=1.6質量%、MgF2の量=0.5質量%)を得た。
複合体B11に添加するフッ化アンモニウムを1.18g(リチウムイオン二次電池用正極活物質中におけるMgF2換算量で1.0質量%に相当)、及び溶液Bを調整するためのLiOH・H2Oの代わりに、酢酸マグネシウム四水和物 1.39gを用いた以外、実施例1-1と同様の方法でリチウムイオン二次電池用正極活物質(LiFe0.2Mn0.8PO4、炭素の量=1.6質量%、MgF2の量=1.0質量%)を得た。
得られた複合体B11に水50mLを添加して、フッ化アンモニウム及びLiOH・H2Oを用いることなく、溶液Bを調製した以外、実施例1-1と同様にして、リチウムイオン二次電池用正極活物質(LiFe0.2Mn0.8PO4、炭素の量=1.6質量%、金属フッ化物担持なし)を得た。
LiOH・H2O 0.428kg、Na4SiO4・nH2O 1.40kgに超純水3.75Lを混合してスラリー水を得た。次いで、得られたスラリー水に、FeSO4・7H2O 0.39kg、MnSO4・5H2O 0.79kg、及びZr(SO4)2・4H2O 53gを添加し、25℃の温度に保持しながら速度400rpmにて30分間撹拌して、スラリー水a21を得た。このとき、添加したFeSO4・7H2O、MnSO4・5H2O及びZr(SO4)2・4H2Oのモル比(FeSO4・7H2O:MnSO4・5H2O:Zr(SO4)2・4H2O)は、28:66:3であった。
次いで、得られたスラリー水a21を蒸気加熱式オートクレーブ内に設置した合成容器に投入した。投入後、隔膜分離装置により水(溶存酸素濃度0.5mg/L未満)を加熱して得た飽和蒸気を用いて、150℃で12時間攪拌しながら加熱した。オートクレーブの圧力は0.4MPaであった。生成した結晶をろ過し、次いで結晶1質量部に対し、12質量部の水により洗浄した。洗浄した結晶を-50℃で12時間凍結乾燥して酸化物(粉末、式(B)で表される化学組成:Li2Fe0.28Mn0.66Zr0.03SiO4、BET比表面積35m2/g、平均粒径50nm)を得た。
複合体B21に添加するLiOHを0.066g、フッ化アンモニウムを0.059g(リチウムイオン二次電池用正極活物質中におけるLiFの担持量換算で1.0質量%に相当)とした以外、実施例2-1と同様の方法でリチウムイオン二次電池用正極活物質(Li2Fe0.28Mn0.66Zr0.03SiO4、炭素の量=7.0質量%、LiFの量=1.0質量%)を得た。
複合体B21に添加するLiOHを0.132g、フッ化アンモニウムを0.118g(リチウムイオン二次電池用正極活物質100質量%中におけるLiFの担持量換算で2.0質量%に相当)とした以外、実施例2-1と同様の方法でリチウムイオン二次電池用正極活物質(Li2Fe0.28Mn0.66Zr0.03SiO4、炭素の量=7.0質量%、LiFの量=2.0質量%)を得た。
複合体B21に添加するLiOHの代わりにAl(OH)30.078g、フッ化アンモニウムを0.353g(リチウムイオン二次電池用正極活物質100質量%中におけるAlF2の担持量換算で2.0質量%に相当)とした以外、実施例2-1と同様の方法でリチウムイオン二次電池用正極活物質(Li2Fe0.28Mn0.66Zr0.03SiO4、炭素の量=7.0質量%、AlF3の量=2.0質量%)を得た。
複合体B21に添加するLiOHの代わりにMg(CH3COO)2・4H2O0.277g、フッ化アンモニウムを0.236g(リチウムイオン二次電池用正極活物質中におけるMgF2の担持量換算で2.0質量%に相当)とした以外、実施例2-1と同様の方法でリチウムイオン二次電池用正極活物質(Li2Fe0.28Mn0.66Zr0.03SiO4、炭素の量=7.0質量%、MgF2の量=2.0質量%)を得た。
複合体B21に添加するLiOHを0.396g、フッ化アンモニウムを0.353g(リチウムイオン二次電池用正極活物質中におけるLiFの担持量換算で6.0質量%に相当)とした以外、実施例2-1と同様の方法でリチウムイオン二次電池用正極活物質(Li2Fe0.28Mn0.66Zr0.03SiO4、炭素の量=7.0質量%、LiFの量=6.0質量%)を得た。
金属フッ化物を添加しなかった以外、実施例2-1と同様の方法でリチウムイオン二次電池用正極活物質(Li2Fe0.28Mn0.66Zr0.03SiO4、炭素の量=7.0質量%、金属フッ化物担持なし)を得た。
NaOH 0.60kgと水 9.0Lを混合して溶液を得た。次いで、得られた溶液を、25℃の温度に保持しながら5分間撹拌しつつ85%のリン酸水溶液0.577kgを35mL/分で滴下し、続いて12時間、400rpmの速度で撹拌することにより、混合物B31を含有するスラリーを得た。かかるスラリーは、リン1モルに対し、3.00モルのナトリウムを含有していた。得られたスラリーに対し、窒素ガスをパージして溶存酸素濃度を0.5mg/Lに調整した後、FeSO4・7H2O 0.139kg、MnSO4・5H2O 0.964kg、MgSO4・7H2O 0.124kgを添加した。このとき、添加したFeSO4・7H2O、MnSO4・5H2O及びMgSO4・7H2Oのモル比(FeSO4・7H2O:MnSO4・5H2O:MgSO4・7H2Oは、10:80:10であった。
次いで、得られたスラリー水a31を窒素ガスでパージしたオートクレーブに投入し、200℃で3時間水熱反応を行った。オートクレーブ内の圧力は、1.4MPaであった。生成した結晶をろ過し、次いで結晶1質量部に対し、12質量部の水により洗浄した。洗浄した結晶を-50℃で12時間凍結乾燥して酸化物X31(粉末、式(C)で表される化学組成:NaFe0.1Mn0.8Mg0.1PO4、BET比表面積15m2/g、平均粒径100nm)を得た。
複合体B31に添加するLiOHを0.066g、フッ化アンモニウムを0.059g(ナトリウムイオン二次電池用正極活物質中におけるLiFの担持量換算で1.0質量%に相当)とした以外、実施例3-1と同様の方法でナトリウムイオン二次電池用正極活物質(NaFe0.1Mn0.8Mg0.1PO4、炭素の量=4.0質量%、LiFの量=1.0質量%)を得た。
複合体B31に添加するLiOHを0.132g、フッ化アンモニウムを0.118g(ナトリウムイオン二次電池用正極活物質中におけるLiFの担持量換算で2.0質量%に相当)とした以外、実施例3-1と同様の方法でナトリウムイオン二次電池用正極活物質(NaFe0.1Mn0.8Mg0.1PO4、炭素の量=4.0質量%、LiFの量=2.0質量%)を得た。
複合体B31に添加するLiOHの代わりにAl(OH)30.078g、フッ化アンモニウムを0.353g(ナトリウムイオン二次電池用正極活物質中におけるAlF3の担持量換算で2.0質量%に相当)とした以外、実施例3-1と同様の方法でナトリウムイオン二次電池用正極活物質(NaFe0.1Mn0.8Mg0.1PO4、炭素の量=4.0質量%、AlF3の量=2.0質量%)を得た。
複合体B31に添加するLiOHの代わりにMg(CH3COO)2・4H2O0.277g、フッ化アンモニウムを0.236g(ナトリウムイオン二次電池用正極活物質中におけるMgF3の担持量換算で2.0質量%に相当)とした以外、実施例3-1と同様の方法でナトリウムイオン二次電池用正極活物質(NaFe0.1Mn0.8Mg0.1PO4、炭素の量=4.0質量%、MgF3の量=2.0質量%)を得た。
複合体B31に添加するLiOHを0.396g、フッ化アンモニウムを0.353g(ナトリウムイオン二次電池用正極活物質中におけるLiFの担持量換算で6.0質量%に相当)とした以外、実施例3-1と同様の方法でナトリウムイオン二次電池用正極活物質(NaFe0.1Mn0.8Mg0.1PO4、炭素の量=4.0質量%、LiFの量=6.0質量%)を得た。
金属フッ化物を添加しなかった以外、実施例3-1と同様の方法でナトリウムイオン二次電池用正極活物質(NaFe0.1Mn0.8Mg0.1PO4、炭素の量=4.0質量%、金属フッ化物担持なし)を得た。
LiOH・H2O 12.72g、及び水 90mLを混合して混合物A41(スラリー水)を得た。次いで、得られた混合物A41を、25℃の温度に保持しながら5分間撹拌しつつ85%のリン酸水溶液 11.53gを35mL/分で滴下し、続いて窒素ガスパージ下で12時間、400rpmの速度で撹拌することにより、混合物B41(スラリー水、溶存酸素濃度0.5mg/L)を得た。かかる混合物B41は、リン1モルに対し、2.97モルのリチウムを含有していた。
次いで、得られたスラリー水b41を蒸気加熱式オートクレーブ内に設置した合成容器に投入した。投入後、隔膜分離装置により水(溶存酸素濃度0.5mg/L未満)を加熱して得た飽和蒸気を用いて、170℃で1時間攪拌しながら加熱した。オートクレーブ内の圧力は、0.8MPaであった。生成した結晶をろ過し、次いで結晶1質量部に対し、12質量部の水により洗浄した。洗浄した結晶を-50℃で12時間凍結乾燥して複合体D41(粉末、式(A)で表される酸化物の化学組成:LiFe0.2Mn0.8PO4、BET比表面積21m2/g、平均粒径60nm)を得た。
複合体D41に添加するLiOHを0.066g、フッ化アンモニウムを0.059g(リチウムイオン二次電池用正極活物質中におけるLiFの担持量換算で1.0質量%に相当)とした以外、実施例4-1と同様の方法でリチウムイオン二次電池用正極活物質(LiFe0.2Mn0.8PO4、炭素の量=3.0質量%、LiFの量=1.0質量%)を得た。
複合体D41に添加するLiOHを0.132g、フッ化アンモニウムを0.118g(リチウムイオン二次電池用正極活物質中におけるLiFの担持量換算で2.0質量%に相当)とした以外、実施例4-1と同様の方法でリチウムイオン二次電池用正極活物質(LiFe0.2Mn0.8PO4、炭素の量=3.0質量%、LiFの量=2.0質量%)を得た。
複合体D41に添加するLiOHの代わりにAl(OH)3を0.078g、フッ化アンモニウムを0.353g(リチウムイオン二次電池用正極活物質中におけるAlF3の担持量換算で2.0質量%に相当)とした以外、実施例4-1と同様の方法でリチウムイオン二次電池用正極活物質(LiFe0.2Mn0.8PO4、炭素の量=3.0質量%、AlF3の量=2.0質量%)を得た。
複合体D41に添加するLiOHの代わりにMg(CH3COO)2・4H2Oを0.277g、フッ化アンモニウムを0.236g(リチウムイオン二次電池用正極活物質中におけるMgF2の担持量換算で2.0質量%に相当)とした以外、実施例4-1と同様の方法でリチウムイオン二次電池用正極活物質(LiFe0.2Mn0.8PO4、炭素の量=3.0質量%、MgF2の量=2.0質量%)を得た。
複合体D41に添加するLiOHを0.396g、フッ化アンモニウムを0.353g(リチウムイオン二次電池用正極活物質中におけるLiFの担持量換算で5.7質量%に相当)とした以外、実施例4-1と同様の方法でリチウムイオン二次電池用正極活物質(LiFe0.2Mn0.8PO4、炭素の量=3.0質量%、LiFの量=5.7質量%)を得た。
金属フッ化物を添加しなかった以外、実施例4-1と同様の方法でリチウムイオン二次電池用正極活物質(LiFe0.2Mn0.8PO4、炭素の量=3.0質量%、金属フッ化物担持なし)を得た。
LiOH・H2O 4.28g、Na4SiO4・nH2O 13.97gに超純水37.5mLを混合して混合物B51(スラリー水、溶存酸素濃度0.5mg/L)を得た。この混合物B51に、FeSO4・7H2O 3.92g、MnSO4・5H2O 7.93g、及びZr(SO4)2・4H2O 0.53gを添加し、25℃の温度に保持しながら速度400rpmにて30分間撹拌して、スラリー水b51を得た。このとき、添加したFeSO4・7H2O、MnSO4・5H2O及びZr(SO4)2・4H2Oのモル比(FeSO4・7H2O:MnSO4・5H2O:Zr(SO4)2・4H2O)は、28:66:3であった。
次いで、得られたスラリー水b51を蒸気加熱式オートクレーブ内に設置した合成容器に投入した。投入後、隔膜分離装置により水(溶存酸素濃度0.5mg/L未満)を加熱して得た飽和蒸気を用いて、150℃で12時間攪拌しながら加熱した。オートクレーブの圧力は0.4MPaであった。生成した結晶をろ過し、次いで結晶1質量部に対し、12質量部の水により洗浄した。洗浄した結晶を-50℃で12時間凍結乾燥して複合体D51(粉末、式(B)で表される酸化物の化学組成:Li2Fe0.28Mn0.66Zr0.03SiO4、BET比表面積35m2/g、平均粒径50nm)を得た。
複合体D51に添加するLiOHを0.066g、フッ化アンモニウムを0.059g(リチウムイオン二次電池用正極活物質中におけるLiFの担持量換算で1.0質量%に相当)とした以外、実施例5-1と同様の方法でリチウムイオン二次電池用正極活物質(Li2Fe0.28Mn0.66Zr0.03SiO4、炭素の量=10.0質量%、LiFの量=1.0質量%)を得た。
複合体D51に添加するLiOHを0.132g、フッ化アンモニウムを0.118g(リチウムイオン二次電池用正極活物質中におけるLiFの担持量換算で2.0質量%に相当)とした以外、実施例5-1と同様の方法でリチウムイオン二次電池用正極活物質(Li2Fe0.28Mn0.66Zr0.03SiO4、炭素の量=10.0質量%、LiFの量=2.0質量%)を得た。
複合体D51に添加するLiOHの代わりにAl(OH)3を0.078g、フッ化アンモニウムを0.353g(リチウムイオン二次電池用正極活物質中におけるAlF2の担持量換算で2.0質量%に相当)とした以外、実施例5-1と同様の方法でリチウムイオン二次電池用正極活物質(Li2Fe0.28Mn0.66Zr0.03SiO4、炭素の量=10.0質量%、AlF2の量=2.0質量%)を得た。
複合体D51に添加するLiOHの代わりにMg(CH3COO)2・4H2Oを0.277g、フッ化アンモニウムを0.236g(リチウムイオン二次電池用正極活物質中におけるMgF2の担持量換算で2.0質量%に相当)とした以外、実施例5-1と同様の方法でリチウムイオン二次電池用正極活物質(Li2Fe0.28Mn0.66Zr0.03SiO4、炭素の量=10.0質量%、MgF2の量=2.0質量%)を得た。
複合体D51に添加するLiOHを0.396g、フッ化アンモニウムを0.353g(リチウムイオン二次電池用正極活物質中におけるLiFの担持量換算で6.0質量%に相当)とした以外、実施例5-1と同様の方法でリチウムイオン二次電池用正極活物質(Li2Fe0.28Mn0.66Zr0.03SiO4、炭素の量=10.0質量%、LiFの量=6.0質量%)を得た。
金属フッ化物を添加しなかった以外、実施例5-1と同様の方法でリチウムイオン二次電池用正極活物質(Li2Fe0.28Mn0.66Zr0.03SiO4、炭素の量=10.0質量%、金属フッ化物担持なし)を得た。
NaOH 6.00g、水 90mLを混合して溶液を得た。次いで、得られた溶液を、25℃の温度に保持しながら5分間撹拌しつつ85%のリン酸水溶液 5.77gを35mL/分で滴下し、続いて12時間、400rpmの速度で撹拌することにより、混合物B61(スラリー水)を得た。かかる混合物B61は、リン1モルに対し、3.00モルのナトリウムを含有していた。得られた混合物B61に対し、窒素ガスをパージして溶存酸素濃度を0.5mg/Lに調整した後、FeSO4・7H2O 1.39g、MnSO4・5H2O 9.64g、MgSO4・7H2O 1.24g、及びグルコース0.59g(ナトリウムイオン二次電池用正極活物質中における炭素原子換算量で1.4質量%に相当)を添加してスラリー水b61を得た。このとき、添加したFeSO4・7H2O、MnSO4・5H2O及びMgSO4・7H2Oのモル比(FeSO4・7H2O:MnSO4・5H2O:MgSO4・7H2Oは、10:80:10であった。
次いで、得られたスラリー水b61を蒸気加熱式オートクレーブ内に設置した、窒素ガスでパージした合成容器に投入した。投入後、隔膜分離装置により水(溶存酸素濃度0.5mg/L未満)を加熱して得た飽和蒸気を用いて、200℃で3時間攪拌しながら加熱した。オートクレーブ内の圧力は、1.4MPaであった。生成した結晶をろ過し、次いで結晶1質量部に対し、12質量部の水により洗浄した。洗浄した結晶を-50℃で12時間凍結乾燥して複合体D61(式(C)で表される酸化物の化学組成:NaFe0.1Mn0.8Mg0.1PO4、BET比表面積15m2/g、平均粒径100nm)を得た。
複合体D61に添加するLiOHを0.066g、フッ化アンモニウムを0.059g(ナトリウムイオン二次電池用正極活物質中におけるLiFの担持量換算で1.0質量%に相当)とした以外、実施例6-1と同様の方法でナトリウムイオン二次電池用正極活物質(NaFe0.1Mn0.8Mg0.1PO4、炭素の量=1.4質量%、LiFの量=1.0質量%)を得た。
複合体D61に添加するLiOHを0.132g、フッ化アンモニウムを0.118g(ナトリウムイオン二次電池用正極活物質中におけるLiFの担持量換算で2.0質量%に相当)とした以外、実施例6-1と同様の方法でナトリウムイオン二次電池用正極活物質(NaFe0.1Mn0.8Mg0.1PO4、炭素の量=1.4質量%、LiFの量=2.0質量%)を得た。
複合体D61に添加するLiOHの代わりにAl(OH)3を0.078g、フッ化アンモニウムを0.353g(ナトリウムイオン二次電池用正極活物質中におけるAlF3の担持量換算で2.0質量%に相当)とした以外、実施例6-1と同様の方法でナトリウムイオン二次電池用正極活物質(NaFe0.1Mn0.8Mg0.1PO4、炭素の量=1.4質量%、AlF3の量=2.0質量%)を得た。
複合体D61に添加するLiOHの代わりにMg(CH3COO)2・4H2Oを0.277g、フッ化アンモニウムを0.236g(ナトリウムイオン二次電池用正極活物質中におけるMgF3の担持量換算で2.0質量%に相当)とした以外、実施例6-1と同様の方法でナトリウムイオン二次電池用正極活物質(NaFe0.1Mn0.8Mg0.1PO4、炭素の量=1.4質量%、MgF3の量=2.0質量%)を得た。
複合体D61に添加するLiOHを0.396g、フッ化アンモニウムを0.353g(ナトリウムイオン二次電池用正極活物質中におけるLiFの担持量換算で6.0質量%に相当)とした以外、実施例6-1と同様の方法でナトリウムイオン二次電池用正極活物質(NaFe0.1Mn0.8Mg0.1PO4、炭素の量=1.4質量%、LiFの量=6.0質量%)を得た。
金属フッ化物を添加しなかった以外、実施例6-1と同様の方法でナトリウムイオン二次電池用正極活物質(NaFe0.1Mn0.8Mg0.1PO4、炭素の量=1.4質量%、金属フッ化物担持なし)を得た。
実施例1-1~6-5及び比較例1-1~6-2で得られた各正極活物質の吸着水分量は、下記方法にしたがって測定した。
正極活物質(複合体粒子)について、温度20℃、相対湿度50%の環境に1日間静置して平衡に達するまで水分を吸着させ、温度150℃まで昇温して20分間保持した後、さらに温度250℃まで昇温して20分間保持したときの、150℃から昇温を再開するときを始点、及び250℃での恒温状態を終えたときを終点とし、始点から終点までの間に揮発した水分量を、カールフィッシャー水分計(MKC-610、京都電子工業(株)製)で測定し、正極活物質における吸着水分量として求めた。
結果を表1及び表2に示す。
実施例1-1~6-5及び比較例1-1~6-2で得られた正極活物質を用い、リチウムイオン二次電池又はナトリウムイオン二次電池の正極を作製した。具体的には、得られた正極活物質、ケッチェンブラック、ポリフッ化ビニリデンを質量比75:20:5の配合割合で混合し、これにN-メチル-2-ピロリドンを加えて充分混練し、正極スラリーを調製した。正極スラリーを厚さ20μmのアルミニウム箔からなる集電体に塗工機を用いて塗布し、80℃で12時間の真空乾燥を行った。
その後、φ14mmの円盤状に打ち抜いてハンドプレスを用いて16MPaで2分間プレスし、正極とした。
次いで、上記の正極を用いてコイン型二次電池を構築した。負極には、φ15mmに打ち抜いたリチウム箔を用いた。電解液には、エチレンカーボネート及びエチルメチルカーボネートを体積比1:1の割合で混合した混合溶媒に、LiPF6(リチウムイオン二次電池の場合)又はNaPF6(ナトリウムイオン二次電池の場合)を1mol/Lの濃度で溶解したものを用いた。セパレータには、ポリプロピレンなどの高分子多孔フィルムなど、公知のものを用いた。これらの電池部品を露点が-50℃以下の雰囲気で常法により組み込み収容し、コイン型二次電池(CR-2032)を製造した。
容量保持率(%)=(50サイクル後の放電容量)/(1サイクル後の放
電容量)×100 ・・・(2)
結果を表1及び表2に示す。
Claims (10)
- 少なくとも鉄又はマンガンを含む下記式(A)、(B)又は(C):
LiFeaMnbMcPO4・・・(A)
(式(A)中、MはMg、Ca、Sr、Y、Zr、Mo、Ba、Pb、Bi、La、Ce、Nd又はGdを示す。a、b及びcは、0≦a≦1、0≦b≦1、0≦c≦0.2、及び2a+2b+(Mの価数)×c=2を満たし、かつa+b≠0を満たす数を示す。)
Li2FedMneNfSiO4・・・(B)
(式(B)中、NはNi、Co、Al、Zn、V又はZrを示す。d、e及びfは、0≦d≦1、0≦e≦1、及び0≦f<1、2d+2e+(Nの価数)×f=2を満たし、かつd+e≠0を満たす数を示す。)
NaFegMnhQiPO4・・・(C)
(式(C)中、QはMg、Ca、Co、Sr、Y、Zr、Mo、Ba、Pb、Bi、La、Ce、Nd又はGdを示す。g、h及びiは、0≦g≦1、0≦h≦1、0≦i<1、及び2g+2h+(Qの価数)×i=2を満たし、かつg+h≠0を満たす数を示す。)
で表される酸化物に、水不溶性導電性炭素材料及び水溶性炭素材料が炭化されてなる炭素から選ばれる1種又は2種と、0.1~5質量%の金属フッ化物とが担持されてなる二次電池用正極活物質。 - 酸化物と、水不溶性導電性炭素材料及び水溶性炭素材料が炭化されてなる炭素から選ばれる1種又は2種とを含む複合体に、金属フッ化物が担持されてなる請求項1に記載の二次電池用正極活物質。
- 水不溶性導電性炭素材料が、ケッチェンブラック、又はグラファイトである請求項1又は2に記載の二次電池用正極活物質。
- 水溶性炭素材料が、糖類、ポリオール、ポリエーテル、及び有機酸から選ばれる1種又は2種以上である請求項1~3のいずれか1項に記載の二次電池用正極活物質。
- 金属フッ化物の金属が、リチウム、ナトリウム、マグネシウム、カルシウム、及びアルミニウムから選ばれる請求項1~4のいずれか1項に記載の二次電池用正極活物質。
- 金属フッ化物が、酸化物と、水不溶性導電性炭素材料及び水溶性炭素材料が炭化されてなる炭素から選ばれる1種又は2種とを含む複合体、並びに金属フッ化物の前駆体が湿式混合され、焼成されて酸化物に担持されてなる請求項2~5のいずれか1項に記載の二次電池用正極活物質。
- 金属フッ化物の前駆体が、フッ化アンモニウム、フッ化水素酸、及び次亜フッ素酸から選ばれるフッ素化合物、並びに酢酸金属塩、硝酸金属塩、乳酸金属塩、シュウ酸金属塩、金属水酸化物、金属エトキシド、金属イソプロポキシド、及び金属ブトキシドから選ばれる金属化合物である請求項6に記載の二次電池用正極活物質。
- リチウム化合物又はナトリウム化合物、リン酸化合物又はケイ酸化合物、並びに少なくとも鉄化合物又はマンガン化合物を含む金属塩を含有するスラリー水aを水熱反応に付して酸化物Xを得る工程(I-1)、
得られた酸化物Xに水不溶性導電性炭素材料を添加して乾式混合し、複合体Aを得る工程(II-1)、並びに
得られた複合体Aに、複合体100質量部に対して0.1~40質量部の金属フッ化物の前駆体を添加して湿式混合し、焼成する工程(III-1)
を備える、請求項1~7のいずれか1項に記載の二次電池用正極活物質の製造方法。 - 工程(II-1)における乾式混合が、酸化物と水不溶性導電性炭素材料とを予備混合し、次いで圧縮力及びせん断力を付加しながら混合する混合である請求項8に記載の二次電池用正極活物質の製造方法。
- リチウム化合物又はナトリウム化合物、リン酸化合物又はケイ酸化合物、並びに少なくとも鉄化合物又はマンガン化合物を含む金属塩を含有し、かつ水溶性炭素材料を含有するスラリー水bを水熱反応に付して複合体Dを得る工程(I-2)、並びに
得られた複合体Dに、複合体100質量部に対して0.1~40質量部の金属フッ化物金属フッ化物の前駆体を添加して湿式混合し、焼成する工程(II-2)
を備える、請求項1~7のいずれか1項に記載の二次電池用正極活物質の製造方法。
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JP6322730B1 (ja) * | 2017-01-06 | 2018-05-09 | 太平洋セメント株式会社 | リチウムイオン二次電池用正極活物質及びその製造方法 |
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CN109461932A (zh) * | 2018-09-20 | 2019-03-12 | 浙江大学 | 一种高容量钠离子电池正极材料及其制备方法 |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2005041327A1 (ja) * | 2003-10-27 | 2005-05-06 | Mitsui Engineering & Shipbuilding Co.,Ltd. | 二次電池用正極材料、二次電池用正極材料の製造方法、および二次電池 |
JP2011210693A (ja) * | 2010-03-12 | 2011-10-20 | Equos Research Co Ltd | 二次電池用正極 |
JP2013524440A (ja) * | 2010-04-02 | 2013-06-17 | エンビア・システムズ・インコーポレイテッド | ドープされた正極活物質、およびそれより構成されるリチウムイオン二次電池 |
WO2013128936A1 (ja) * | 2012-02-28 | 2013-09-06 | 株式会社豊田自動織機 | 活物質複合体及びその製造方法、非水電解質二次電池用正極活物質、並びに非水電解質二次電池 |
WO2014063244A1 (en) * | 2012-10-22 | 2014-05-01 | HYDRO-QUéBEC | Method of producing electrode material for lithium-ion secondary battery and lithium-ion battery using such electrode material |
JP2014143032A (ja) * | 2013-01-23 | 2014-08-07 | Hitachi Ltd | リチウムイオン二次電池用正極活物質及びリチウムイオン二次電池 |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CA2270771A1 (fr) | 1999-04-30 | 2000-10-30 | Hydro-Quebec | Nouveaux materiaux d'electrode presentant une conductivite de surface elevee |
JP4187524B2 (ja) | 2002-01-31 | 2008-11-26 | 日本化学工業株式会社 | リチウム鉄リン系複合酸化物炭素複合体、その製造方法、リチウム二次電池正極活物質及びリチウム二次電池 |
JP2008260666A (ja) | 2007-04-13 | 2008-10-30 | Kyushu Univ | ナトリウム二次電池用活物質およびその製造方法 |
US20110008233A1 (en) | 2009-07-10 | 2011-01-13 | Semiconductor Energy Laboratory Co., Ltd. | Positive electrode active material |
CN108767206A (zh) * | 2011-11-15 | 2018-11-06 | 电化株式会社 | 复合粒子及其制造方法、二次电池用电极材料及二次电池 |
JP6292739B2 (ja) | 2012-01-26 | 2018-03-14 | Jx金属株式会社 | リチウムイオン電池用正極活物質、リチウムイオン電池用正極、及び、リチウムイオン電池 |
JP5478693B2 (ja) * | 2012-03-23 | 2014-04-23 | 太平洋セメント株式会社 | 二次電池用正極活物質及びその製造方法 |
-
2015
- 2015-09-17 KR KR1020177025727A patent/KR102385969B1/ko active IP Right Grant
- 2015-09-17 WO PCT/JP2015/076386 patent/WO2016151891A1/ja active Application Filing
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2005041327A1 (ja) * | 2003-10-27 | 2005-05-06 | Mitsui Engineering & Shipbuilding Co.,Ltd. | 二次電池用正極材料、二次電池用正極材料の製造方法、および二次電池 |
JP2011210693A (ja) * | 2010-03-12 | 2011-10-20 | Equos Research Co Ltd | 二次電池用正極 |
JP2013524440A (ja) * | 2010-04-02 | 2013-06-17 | エンビア・システムズ・インコーポレイテッド | ドープされた正極活物質、およびそれより構成されるリチウムイオン二次電池 |
WO2013128936A1 (ja) * | 2012-02-28 | 2013-09-06 | 株式会社豊田自動織機 | 活物質複合体及びその製造方法、非水電解質二次電池用正極活物質、並びに非水電解質二次電池 |
WO2014063244A1 (en) * | 2012-10-22 | 2014-05-01 | HYDRO-QUéBEC | Method of producing electrode material for lithium-ion secondary battery and lithium-ion battery using such electrode material |
JP2014143032A (ja) * | 2013-01-23 | 2014-08-07 | Hitachi Ltd | リチウムイオン二次電池用正極活物質及びリチウムイオン二次電池 |
Cited By (5)
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---|---|---|---|---|
JP6322730B1 (ja) * | 2017-01-06 | 2018-05-09 | 太平洋セメント株式会社 | リチウムイオン二次電池用正極活物質及びその製造方法 |
JP6322729B1 (ja) * | 2017-01-06 | 2018-05-09 | 太平洋セメント株式会社 | リチウムイオン二次電池用正極活物質及びその製造方法 |
JP2018113101A (ja) * | 2017-01-06 | 2018-07-19 | 太平洋セメント株式会社 | リチウムイオン二次電池用正極活物質及びその製造方法 |
JP2018113102A (ja) * | 2017-01-06 | 2018-07-19 | 太平洋セメント株式会社 | リチウムイオン二次電池用正極活物質及びその製造方法 |
CN109461932A (zh) * | 2018-09-20 | 2019-03-12 | 浙江大学 | 一种高容量钠离子电池正极材料及其制备方法 |
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