Positive electrode active material particle mixture for lithium ion secondary battery and method for producing the same

Abstract

To provide a positive electrode active material particle mixture for a lithium ion secondary battery, which enables the satisfactory enhancement in capacity and storability as to a lithium ion secondary battery while using lithium manganese iron phosphate-based particles.SOLUTION: A positive electrode active material particle mixture for a lithium ion secondary battery comprises: 10 mass% or more of particles (A) including a substance represented by the formula (A), LiaMnbFecM1xPO4 (A) (in the formula (A), M1 represents Mg, Al, Ti, Cu, Zn, Nb, Co, Ni, Ca, Sr, Y, Zr, Mo, Ba, Pb, Bi, La, Ce, Nd or Gd; a, b, c and x are numbers that satisfy 0<a≤1.2, 0≤b≤1.2, 0≤c≤1.2, 0≤x≤0.3 and b+c≠0 and a+(Valence number of Mn)×b+(Valence number of Fe)×c+(Valence number of M1)×x=3), and having a tap density of 0.3-1.2 g / cm3, of which the volume of pores of 10-3000 nm in pore diameter is 0.2-0.7 mL / g.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a positive electrode active material particle mixture for a lithium ion secondary battery and a method for producing the same, for obtaining a lithium ion secondary battery having a high capacity and excellent storage characteristics.

Background Art

[0002] Secondary batteries such as lithium ion secondary batteries are used in a wide range of fields such as mobile phones, digital cameras, notebook PCs, hybrid vehicles, and electric vehicles. As a positive electrode material for such lithium ion secondary batteries, lithium manganese x Fe 1-x lithium manganese iron phosphate-based particles such as PO4 are regarded as promising. On the other hand, lithium manganese iron phosphate-based particles have low conductivity, and there is still room for improvement in order to sufficiently improve the battery characteristics in the obtained lithium ion secondary battery. Therefore, various developments have been made conventionally.

[0003] For example, Patent Document 1 discloses a positive electrode for a secondary battery containing a lithium nickel cobalt manganese composite oxide together with lithium manganese iron phosphate in order to obtain a secondary battery having excellent energy density, and is more effective in improving the initial Coulomb efficiency in a lithium ion secondary battery than when containing lithium manganese iron phosphate alone.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the technology described in the above patent document, in the obtained lithium-ion secondary battery, in order to improve the storage characteristics while increasing the capacity, there is still a situation that requires improvement.

[0006] Therefore, an object of the present invention is to provide a positive electrode active material particle mixture for a lithium-ion secondary battery that can sufficiently enhance the storage characteristics together with the capacity in a lithium-ion secondary battery while using lithium iron manganese phosphate-based particles.

Means for Solving the Problems

[0007] Therefore, as a result of intensive studies to solve the above problems, the present inventor has found that by using specific lithium iron manganese phosphate-based particles having many voids inside the particles, a particle mixture as a positive electrode material capable of realizing a lithium-ion secondary battery exhibiting excellent storage characteristics while having a high capacity can be obtained.

[0008] That is, the present invention provides the following formula (A): Li a Mn b Fe c M 1 x PO4···(A) (In formula (A), M 1 represents Mg, Al, Ti, Cu, Zn, Nb, Co, Ni, Ca, Sr, Y, Zr, Mo, Ba, Pb, Bi, La, Ce, Nd or Gd. a, b, c, and x satisfy 0 < a ≤ 1.2, 0 ≤ b ≤ 1.2, 0 ≤ c ≤ 1.2, 0 ≤ x ≤ 0.3, and b + c ≠ 0, and a + (valence of Mn) × b + (valence of Fe) × c + (valence of M 1 ) × x = 3. ) represented by, and having a tap density of 0.3 g / cm 3 ~1.2 g / cm 3 and a pore volume in a pore diameter of 10 nm to 3000 nm of 0.2 mL / g to 0.7 mL / g, and provides a positive electrode active material particle mixture for a lithium-ion secondary battery containing 10% by mass or more of particles (A).

[0009] Further, the present invention includes the following steps (I) to (III): (I) A step of subjecting slurry water i obtained by mixing a metal compound containing a lithium compound, a manganese compound and / or an iron compound, a phosphoric acid compound, and water, or slurry water i' obtained by mixing lithium phosphate particles, a metal compound containing a manganese compound and / or an iron compound, and water to a hydrothermal reaction to obtain powder a; (II) A step of spray-drying slurry water ii obtained by adding and mixing the obtained powder a, a foaming agent, and water to obtain granulated body b; (III) A step of firing the obtained granulated body b provided, and a method for producing a positive electrode active material particle mixture for a lithium ion secondary battery, which comprises mixing particles (A) obtained by the production method.

Advantages of the Invention

[0010] According to the positive electrode active material particle mixture for a lithium ion secondary battery of the present invention, since it contains particles (A) which are lithium manganese iron phosphate-based particles having many voids inside the particles and showing good disintegrability during the pressing step in the battery manufacturing process, it can be closely and effectively intertwined with other particles, and in the obtained lithium ion secondary battery, the capacity can be effectively increased while improving the storage characteristics.

Embodiments for Carrying Out the Invention

[0011] Hereinafter, the present invention will be described in detail. The positive electrode active material particle mixture for a lithium ion secondary battery of the present invention has the following formula (A): Li a Mn b Fe c M 1 x PO4···(A) (In formula (A), M 1represents Mg, Al, Ti, Cu, Zn, Nb, Co, Ni, Ca, Sr, Y, Zr, Mo, Ba, Pb, Bi, La, Ce, Nd or Gd. a, b, c, and x satisfy 0 < a ≤ 1.2, 0 ≤ b ≤ 1.2, 0 ≤ c ≤ 1.2, 0 ≤ x ≤ 0.3, and b + c ≠ 0, and a + (valence of Mn) × b + (valence of Fe) × c + (valence of M 1 represents a number that satisfies) × x = 3.) is represented by, and the tap density is 0.3 g / cm 3 ~1.2 g / cm 3 and the pore volume in the pore diameter range of 10 nm to 3000 nm is 0.2 mL / g to 0.7 mL / g. The particles (A) contain 10% by mass or more.)

[0012] Thus, the positive electrode active material particle mixture for a lithium ion secondary battery of the present invention contains particles (A) which are so-called lithium manganese iron phosphate-based particles represented by the above formula (A). Such particles (A) have many voids inside the particles so that the tap density and the pore volume show values within the above specific ranges. Therefore, during the pressing process in the battery manufacturing process, they moderately collapse and are well and uniformly mixed with other particles contained in the positive electrode active material particle mixture for a lithium ion secondary battery, and the particles are closely and effectively intertwined. In the obtained lithium ion secondary battery, while effectively increasing the capacity, it is possible to effectively suppress the decrease in capacity when stored at a high temperature in a charged state, and it is possible to have excellent storage characteristics.)

[0013] The positive electrode active material particle mixture for a lithium ion secondary battery of the present invention uses, as the particles (A), the following formula (A): Li a Mn b Fe c M 1 x PO4 ··· (A) (In the formula (A), M 1represents Mg, Al, Ti, Cu, Zn, Nb, Co, Ni, Ca, Sr, Y, Zr, Mo, Ba, Pb, Bi, La, Ce, Nd or Gd. a, b, c, and x satisfy 0 < a ≤ 1.2, 0 ≤ b ≤ 1.2, 0 ≤ c ≤ 1.2, 0 ≤ x ≤ 0.3, and b + c ≠ 0, and satisfy a + (valence of Mn) × b + (valence of Fe) × c + (valence of M 1 × x = 3. ) contains particles represented by

[0014] The particles (A) represented by the above formula (A) are olivine-type lithium manganese iron phosphate particles containing at least manganese (Mn) or iron (Fe), and are secondary particles formed by aggregation of primary particles. In formula (A), M 1 represents Mg, Al, Ti, Cu, Zn, Nb, Co, Ni, Ca, Sr, Y, Zr, Mo, Ba, Pb, Bi, La, Ce, Nd or Gd, preferably Mg or Zr. a satisfies 0 < a ≤ 1.2, preferably 0.6 ≤ a ≤ 1.2, more preferably 0.65 ≤ a ≤ 1.15, and still more preferably 0.7 ≤ a ≤ 1.1. b satisfies 0 ≤ b ≤ 1.2, preferably 0.25 ≤ b ≤ 0.8, more preferably 0.35 ≤ b ≤ 0.8. c satisfies 0 ≤ c ≤ 1.2, preferably 0.2 ≤ c ≤ 0.75, more preferably 0.2 ≤ c ≤ 0.65. And these b and c satisfy b + c ≠ 0. x satisfies 0 ≤ x ≤ 0.3, preferably 0 ≤ x ≤ 0.15, more preferably 0 ≤ x ≤ 0.1. And these a, b, c and x are numbers that satisfy a + (valence of Mn) × b + (valence of Fe) × c + (valence of M) × x = 3. More specifically, examples of such particles (A) include, for example, LiMnPO4, LiFePO4, LiMn 0.8 Fe 0.2 PO4, LiMn 0.1 Fe 0.9 PO4, LiMn 0.8 Fe 0.1 Mg 0.1 PO4, LiMn 0.8 Fe 0.1 Zr 0.05 PO4, etc.

[0015] The tap density of the particles (A) is 0.3 g / cm 3 ~1.2 g / cm 3 from the viewpoint of effectively suppressing unnecessary elution of metals and exhibiting good disintegrability, preferably 0.3 g / cm 3 ~1.0 g / cm 3 and more preferably 0.3 g / cm 3 ~0.8 g / cm 3 . Note that the tap density means the "tapped bulk density" measured by the method defined in JIS R 1628, "Method for Measuring the Bulk Density of Fine Ceramic Powders", as described below.

[0016] The pore volume of the particles (A) at pore diameters of 10 nm to 3000 nm, in combination with the above tap density, is 0.2 mL / g to 0.7 mL / g from the viewpoint of causing the particles (A) to exhibit good disintegrability and effectively enhancing the storage characteristics in the resulting battery, preferably 0.3 mL / g to 0.7 mL / g, and more preferably 0.4 mL / g to 0.7 mL / g. Note that the pore volume means the value measured by a mercury intrusion porosimeter.

[0017] The average particle diameter of the particles (A) is preferably 6 μm to 20 μm, more preferably 8 μm to 20 μm, and even more preferably 10 μm to 20 μm from the viewpoint of moderately disintegrating during the pressing step in the battery manufacturing process and being well and uniformly mixed with other particles contained in the positive electrode active material particle mixture for the lithium-ion secondary battery. Note that the average particle diameter means the D 50 value (particle diameter at cumulative 50% (median diameter)) obtained from the volume-based particle size distribution based on the laser diffraction / scattering method.

[0018] Note that the particles (A) may also be particles having carbon derived from cellulose nanofibers and / or carbon derived from a water-soluble carbon material supported on the surface of the particles from the viewpoint of ensuring excellent capacity. The fiber diameter of the cellulose nanofiber is 1 nm to 1000 nm, and it also has good dispersibility in water, which can effectively suppress the reduction of the electron conduction path and ensure the expression of excellent capacity in the obtained battery. Examples of the water-soluble carbon material include one or more selected from saccharides, polyols, polyethers, and organic acids. More specifically, for example, monosaccharides such as glucose, fructose, galactose, mannose; disaccharides such as maltose, sucrose, cellobiose; polysaccharides such as starch, dextrin; polyols and polyethers such as ethylene glycol, propylene glycol, diethylene glycol, polyethylene glycol, butanediol, propanediol, polyvinyl alcohol, glycerin; and organic acids such as citric acid, tartaric acid, ascorbic acid.

[0019] When carbon derived from cellulose nanofibers and carbon derived from a water-soluble carbon material are supported on the surface of the particle (A), the total amount in terms of atoms of carbon derived from cellulose nanofibers and the amount in terms of atoms of carbon derived from the water-soluble carbon material, that is, the total amount of the supported amount of carbon derived from cellulose nanofibers and the supported amount of carbon derived from the water-soluble carbon material, is preferably 0.8% by mass to 10.0% by mass, more preferably 1.0% by mass to 7.0% by mass, and still more preferably 1.2% by mass to 5.0% by mass in 100% by mass of the particle (A). In addition, the amount in terms of atoms (supported amount) of carbon derived from cellulose nanofibers and the amount in terms of atoms (supported amount) of carbon derived from the water-soluble carbon material present in the particle (A) mean the values obtained by measurement using a carbon-sulfur analyzer.

[0020] From the viewpoint of exhibiting high capacity and excellent storage characteristics in the obtained battery, the content of the particle (A) is 10% by mass or more, preferably 10% by mass to 40% by mass, more preferably 15% by mass to 40% by mass, and still more preferably 20% by mass to 40% by mass in the positive electrode active material particle mixture for a lithium ion secondary battery of the present invention.

[0021] In addition, when the particles (A) carry carbon derived from cellulose nanofibers and / or carbon derived from a water-soluble carbon material on their surfaces, the content of the particles (A) shall also include the amount of carbon carried thereon.

[0022] From the viewpoint of exhibiting high capacity and excellent storage characteristics in the resulting battery, particularly for effectively increasing the capacity, the positive electrode active material particle mixture for a lithium-ion secondary battery of the present invention, together with the above particles (A), further contains the following formula (B): LiNi d Co e Al f M 2 y O2···(B) (In formula (B), M 2 represents one or more elements selected from Mg, Ti, Nb, Fe, Cr, Si, Ga, V, Zn, Cu, Sr, Mo, Zr, Sn, Ta, W, La, Ce, Pb, Bi, and Ge. d, e, f, y are numbers satisfying 0.4 ≦ d < 1, 0 < e ≦ 0.6, 0 < f ≦ 0.3, 0 ≦ y ≦ 0.3, and 3d + 3e + 3f + (valence of M 2 ) × y = 3.) Preferably, it contains particles (B) represented by the formula. Such particles (B) are lithium nickel composite oxide particles having a layered rock salt structure containing at least nickel (Ni), cobalt (Co), and aluminum (Al), and are secondary particles formed by aggregation of primary particles. They have excellent electron conductivity and can greatly contribute to increasing the capacity in the resulting battery by uniformly mixing with fine particles (A) that moderately disintegrate during the pressing process in the battery manufacturing process.

[0023] In formula (B), M 2 represents one or more elements selected from Mg, Ti, Nb, Fe, Cr, Si, Ga, V, Zn, Cu, Sr, Mo, Zr, Sn, Ta, W, La, Ce, Pb, Bi, and Ge, and is preferably Mg or Zn. More specifically, such particles (B) include, for example, LiNi 0.95 Co 0.04 Al 0.01 O2, LiNi0.88 Co 0.10 Al 0.02 O2, LiNi 0.88 Co 0.09 Al 0.03 O2, LiNi 0.85 Co 0.14 Al 0.01 O2, LiNi 0.8 Co 0.15 Al 0.05 O2, LiNi 0.8 Co 0.16 Al 0.04 O2, LiNi 0.8 Co 0.1 Al 0.1 O2, LiNi 0.8 Co 0.15 Al 0.03 Mg 0.03 O2, LiNi 0.8 Co 0.15 Al 0.03 Zn 0.03 Particles composed of O2, etc. are exemplified. Among them, LiNi 0.8 Co 0.15 Al 0.05 Particles composed of O2 are preferred.

[0024] From the viewpoint of effectively increasing the capacity in the resulting battery by being mixed well and uniformly with the particles (A) that disintegrated appropriately during the pressing process in the battery manufacturing process, the average particle diameter of the particles (B) is preferably 4 μm to 13 μm, more preferably 4 μm to 11 μm, and still more preferably 4 μm to 9 μm. Note that the average particle diameter, similar to the particles (A), is the D value (particle diameter at cumulative 50% (median diameter)) obtained from the volume-based particle size distribution based on the laser diffraction / scattering method. 50 It means the value.

[0025] From the viewpoint of exhibiting high capacity and excellent storage characteristics in the resulting battery, the content of the particles (B) in the positive electrode active material particle mixture for the lithium ion secondary battery of the present invention is preferably 50% by mass to 80% by mass, more preferably 50% by mass to 70% by mass, and still more preferably 50% by mass to 60% by mass.

[0026] The positive electrode active material particle mixture for a lithium ion secondary battery of the present invention, from the viewpoint of exhibiting high capacity and excellent storage characteristics in the resulting battery, particularly effectively increasing the capacity, in addition to the above particles (A) and particles (B), further has the following formula (C): LiNi g Co h Mn i M 3 z O2···(C) (In formula (C), M 3 represents one or more elements selected from Mg, Ti, Nb, Fe, Cr, Si, Al, Ga, V, Zn, Cu, Sr, Mo, Zr, Sn, Ta, W, La, Ce, Pb, Bi, and Ge. g, h, i, z are numbers satisfying 0.3 ≦ g < 1, 0 < h ≦ 0.7, 0 < i ≦ 0.7, 0 ≦ z ≦ 0.3, and 3g + 3h + 3i + (valence of M 3 ) × z = 3.) Preferably, it contains particles (C) represented by. Such particles (C) are lithium nickel composite oxide particles having a layered rock salt structure containing at least nickel (Ni), cobalt (Co), and manganese (Mn), and are secondary particles formed by aggregation of primary particles. They have excellent electron conductivity and can contribute greatly to increasing the capacity in the resulting battery by uniformly mixing with particles (B) and fine particles (A) that collapse moderately during the pressing process in the battery manufacturing process.)

[0027] In formula (C), M 3 represents one or more elements selected from Mg, Ti, Nb, Fe, Cr, Si, Al, Ga, V, Zn, Cu, Sr, Mo, Zr, Sn, Ta, W, La, Ce, Pb, Bi, and Ge, and is preferably Mg or Zn.) More specifically, such particles (C) include, for example, LiNi 0.94 Co 0.03 Mn 0.03 O2, LiNi 0.9 Co 0.05 Mn 0.05 O2, LiNi 0.4 Co 0.3 Mn 0.3 O2, LiNi 0.5Co 0.2 Mn 0.3 O2, LiNi 0.33 Co 0.33 Mn 0.34 O2, LiNi 0.8 Co 0.1 Mn 0.1 O2, LiNi 0.6 Co 0.2 Mn 0.2 O2, LiNi 0.33 Co 0.31 Mn 0.33 Mg 0.045 O2, or LiNi 0.33 Co 0.31 Mn 0.33 Zn 0.045 O2 and the like can be mentioned. Among them, LiNi 0.8 Co 0.1 Mn 0.1 O2, LiNi 0.6 Co 0.2 Mn 0.2 Particles composed of a composition with a large Ni content such as O2 are preferred.

[0028] From the viewpoint of effectively increasing the capacity in the resulting battery by being well and uniformly mixed with particles (A) that moderately disintegrated during the pressing process in the battery manufacturing process, the average particle size of particles (C) is preferably 4 μm to 13 μm, more preferably 6 μm to 13 μm, and even more preferably 8 μm to 13 μm. Note that the average particle size, similar to particles (A) and particles (B), means the D 50 value (particle size at cumulative 50% (median diameter)) obtained from the volume-based particle size distribution based on the laser diffraction / scattering method.

[0029] From the viewpoint of exhibiting high capacity and excellent storage characteristics in the resulting battery, the content of particles (C) in the positive electrode active material particle mixture for a lithium ion secondary battery of the present invention is preferably 10% by mass to 40% by mass, more preferably 10% by mass to 35% by mass, and even more preferably 10% by mass to 30% by mass.

[0030] The positive electrode active material particle mixture for a lithium ion secondary battery of the present invention, in addition to the above particles, has the following formula (D): LiM 4 w Co j O2···(D) (In formula (D), M 4 represents one or more elements selected from Ni, Mn, Al, Mg, Ti, V, Cr, Fe, Zr, Ga, and Si. w and j are numbers satisfying 0 ≦ w ≦ 0.1, 0 < j ≦ 1, and (valence of M 4 ) × w + 3j = 3.) It can also contain particles (D) represented by

[0031] In formula (D), M 4 is preferably Ni or Mn, and more preferably 50 mol% or more of M 4 is Ni.) More specifically, examples of such particles (D) include, for example, LiCoO2, LiMn 0.05 Co 0.95 O2, LiAl 0.05 Co 0.95 O2, LiMg 0.03 Co 0.98 O2, LiSi 0.03 Co 0.96 O2, etc. Among them, LiCoO2 is preferred.)

[0032] In addition, the above particles (B), particles (C), and particles (D) may all be particles having carbon derived from cellulose nanofibers and / or carbon derived from a water-soluble carbon material supported on the surface of the particles, similar to the above particles (A).

[0033] The positive electrode active material particle mixture for a lithium ion secondary battery of the present invention comprises the following steps (I) to (III): (I) A step of subjecting slurry water i obtained by mixing a lithium compound, a manganese compound and / or an iron compound-containing metal compound, a phosphoric acid compound, and water, or slurry water i' obtained by mixing lithium phosphate particles, a manganese compound and / or an iron compound-containing metal compound, and water to a hydrothermal reaction to obtain powder a, (II) The step of spray-drying the obtained powder a, the foaming agent, and the slurry water ii obtained by adding and mixing water to obtain granulated particles b. (III) The step of firing the obtained granulated particles b It can be obtained by a production method of mixing particles (A) obtained by a production method comprising: That is, the positive electrode active material particle mixture for a lithium ion secondary battery of the present invention is obtained by a production method in which particles (A) are obtained in advance by a production method comprising the above steps (I) to (III), and then, if necessary, the above particles (B), and particles (C), or other particles are appropriately mixed.

[0034] Step (I) is a step of subjecting slurry water i obtained by mixing a metal compound containing a lithium compound, a manganese compound and / or an iron compound, a phosphoric acid compound, and water, or slurry water i' obtained by mixing lithium phosphate particles, a manganese compound and / or an iron compound, and water to a hydrothermal reaction to obtain powder a, that is, a step of subjecting slurry water i or slurry water i' to a hydrothermal reaction to obtain powder a.

[0035] When slurry water i is used in step (I), examples of the lithium compound include hydroxides (e.g., LiOH·H2O, LiOH), carbonates, sulfates, and acetates. Among them, carbonates are preferred. Examples of the metal compound containing a manganese compound and / or an iron compound include, in addition to manganese compounds and iron compounds, metal (M 1 ) compounds can be used. Examples of the manganese compound include manganese acetate, manganese nitrate, manganese sulfate, etc. These may be used alone or in combination of two or more. Among them, from the viewpoint of enhancing battery characteristics, manganese sulfate is preferred. Examples of the iron compound include iron acetate, iron nitrate, iron sulfate, etc. These may be used alone or in combination of two or more. Among them, from the viewpoint of enhancing battery characteristics, iron sulfate is preferred. Metal (M 1 ) compounds are the M in the above formula (A) 1Sulfates, nitrates, etc. containing metals synonymous with those can be mentioned. Examples of the phosphoric acid compound include orthophosphoric acid (H3PO4, phosphoric acid), metaphosphoric acid, pyrophosphoric acid, tripolyphosphoric acid, tetrapolyphosphoric acid, ammonium phosphate, ammonium hydrogen phosphate, etc. Among these, it is preferable to use phosphoric acid, and it is preferably used as an aqueous solution with a concentration of 70% by mass to 90% by mass.

[0036] In preparing slurry water i in step (I), the order of adding the metal compound containing a lithium compound, a manganese compound and / or an iron compound, the phosphoric acid compound, and water is not particularly limited. After adding the lithium compound, the phosphoric acid compound, and water, the manganese compound and / or the iron compound may be added, or these metal compounds containing the lithium compound, the manganese compound and / or the iron compound, the phosphoric acid compound, and water may be added all at once. The content of the lithium compound in slurry water i obtained by mixing the metal compound containing a lithium compound, a manganese compound and / or an iron compound, the phosphoric acid compound, and water is preferably 5 parts by mass to 50 parts by mass, more preferably 7 parts by mass to 45 parts by mass, per 100 parts by mass of water.

[0037] For example, in step (I), when phosphoric acid is used as the phosphoric acid compound, it is preferable to add phosphoric acid to the slurry water obtained by adding the lithium compound and water, and then add the manganese compound and / or the iron compound to obtain slurry water i. At this time, it is preferable to stir the slurry water in advance before adding the phosphoric acid compound. The stirring time of such slurry water is preferably 1 minute to 15 minutes, more preferably 3 minutes to 10 minutes. Also, the temperature of the slurry water is preferably 20°C to 90°C, more preferably 20°C to 70°C.

[0038] When adding phosphoric acid further, it is preferable to dropwise add phosphoric acid while stirring the slurry water. The dropping rate of phosphoric acid into the slurry water is preferably 15 mL / min to 50 mL / min, more preferably 20 mL / min to 45 mL / min, and even more preferably 28 mL / min to 40 mL / min. Also, the stirring time of the slurry water while dropping phosphoric acid is preferably 0.5 hour to 24 hours, more preferably 3 hours to 12 hours. Further, the stirring speed of the slurry water while dropping phosphoric acid is preferably 200 rpm to 700 rpm, more preferably 250 rpm to 600 rpm, and even more preferably 300 rpm to 500 rpm. When stirring the slurry water, it is further preferable to cool it to a temperature below the boiling point temperature of the slurry water. Specifically, it is preferably cooled to 80°C or lower, and more preferably cooled to 20°C to 60°C.

[0039] The slurry water after mixing the phosphoric acid compound preferably contains 2.0 moles to 4.0 moles of lithium per 1 mole of phosphoric acid, and more preferably contains 2.0 moles to 3.1 moles of lithium. The above lithium compound and phosphoric acid compound may be used so as to obtain such an amount. More specifically, the slurry water after mixing the phosphoric acid compound preferably contains 2.7 moles to 3.3 moles of lithium per 1 mole of phosphoric acid, and more preferably contains 2.8 moles to 3.1 moles of lithium.

[0040] By purging nitrogen into the slurry water after mixing the phosphoric acid compound, the reaction in such slurry water is completed, and powder a', which is a precursor of particle (A), is obtained as a slurry. When nitrogen is purged, the reaction can proceed in a state where the dissolved oxygen concentration in the slurry water is reduced, and the dissolved oxygen concentration of the slurry water containing the obtained powder a' is also effectively reduced. Therefore, the oxidation of the metal compound to be added next can be suppressed. In the slurry water containing such powder a', the precursor of particle (A) exists as fine dispersed particles of lithium phosphate (Li3PO4).

[0041] Next, a manganese compound and an iron compound may be added to the slurry water. The molar ratio of the manganese compound and the iron compound used (manganese compound: iron compound) is preferably 90:10 to 50:50, more preferably 85:15 to 55:45, and even more preferably 80:20 to 60:40. Further, the total addition amount of these metal compounds is preferably 0.99 mol to 1.01 mol, more preferably 0.995 mol to 1.005 mol, per 1 mol of phosphate ions contained in the slurry water.

[0042] In addition, when preparing the slurry water i, when a metal compound containing a lithium compound, a manganese compound and / or an iron compound, a phosphoric acid compound, and water are added together, these lithium compound, manganese compound and / or iron compound-containing metal compound, phosphoric acid compound, and water may have the above-mentioned quantitative relationship, and lithium phosphate (Li3PO4) as a precursor of the particles (A) does not necessarily have to be present in the slurry water i.

[0043] When using the slurry water i' in the step (I), a metal compound containing a manganese compound and an iron compound may be added to the slurry water obtained by mixing lithium phosphate particles and water. The content of lithium phosphate particles in the slurry water i' is preferably 7% by mass to 60% by mass, more preferably 9% by mass to 50% by mass. The molar ratio of the manganese compound and the iron compound used, and the total addition amount of the metal compound are the same as above.

[0044] The addition order of the manganese compound, the iron compound, and the metal (M 1 ) compound is not particularly limited. Further, when adding these metal compounds, an antioxidant may be added as necessary. As such an antioxidant, sodium sulfite (Na2SO3), sodium hydrosulfite (Na2S2O4), aqueous ammonia, etc. can be used. The addition amount of the antioxidant is based on the manganese compound, the iron compound, and the metal (M 1Preferably, it is 0.01 mol to 1 mol, more preferably 0.03 mol to 0.5 mol, per 1 mol of the total amount of the compounds.

[0045] When using the slurry water i', the content of the powder a' in the slurry water i obtained by adding a manganese compound, an iron compound, and a metal (M 1 ) compound and adding an antioxidant or the like as necessary is preferably 10% by mass to 50% by mass, more preferably 15% by mass to 45% by mass, and even more preferably 20% by mass to 40% by mass.

[0046] Next, in step (I), the obtained powder a' and the slurry water i or slurry water i' containing a metal compound containing at least a manganese compound and an iron compound are subjected to a hydrothermal reaction to obtain the powder a.

[0047] The amount of water used when subjecting to the hydrothermal reaction is preferably 10 mol to 50 mol, more preferably 12.5 mol to 45 mol, per 1 mol of phosphate ions contained in the slurry water i (or slurry water i'), from the viewpoints of the solubility of the metal compound, the ease of stirring, and the synthesis efficiency.

[0048] The hydrothermal reaction may be at 100°C or higher, preferably 130°C to 200°C. The hydrothermal reaction is preferably carried out in a pressure-resistant container. When the reaction is carried out at 130°C to 200°C, the pressure at this time is preferably 0.3 MPa to 1.6 MPa, and when the reaction is carried out at 140°C to 160°C, the pressure is preferably 0.3 MPa to 0.6 MPa. The hydrothermal reaction time is preferably 0.1 hour to 48 hours, more preferably 0.2 hour to 24 hours. The obtained powder a is isolated by filtration, washing with water, and drying. As the drying means, freeze drying and vacuum drying are used.

[0049] Step (II) is a step of spray-drying slurry water ii obtained by adding and mixing the powder a obtained in Step (I), a foaming agent, and water to obtain granulated particles b. By using a foaming agent here, gas is generated, and such gas will be present inside the granulated particles b. The gas present inside the granulated particles b is burned out through Step (III) described later, and can be present as voids inside the obtained particles (A).

[0050] Specific examples of the foaming agent include one or more selected from ammonium hydrogen carbonate, ammonium carbonate, sodium carbonate, lithium carbonate, and potassium carbonate. Among them, ammonium hydrogen carbonate and ammonium carbonate are preferred from the viewpoint of effectively introducing many voids inside the particles (A). From the viewpoint of effectively introducing many voids inside the particles (A), the addition amount of the foaming agent is preferably 0.005 parts by mass to 1.25 parts by mass, more preferably 0.006 parts by mass to 0.6 parts by mass, and still more preferably 0.01 parts by mass to 0.3 parts by mass with respect to 100 parts by mass of the powder a.

[0051] From the viewpoint of effectively introducing many voids inside the particles (A) by the foaming agent so that the tap density and pore volume show values within the above specific ranges, the solid content concentration of the slurry water ii is preferably 35% by mass to 65% by mass, more preferably 40% by mass to 65% by mass, and still more preferably 45% by mass to 65% by mass.

[0052] It is preferable to stir the slurry water ii in advance after adding water and before subjecting it to spray drying. The stirring time of such slurry water ii is preferably 3 minutes to 60 minutes, more preferably 5 minutes to 30 minutes. Also, the temperature of the slurry water ii is preferably 10°C to 60°C, more preferably 20°C to 40°C. From the perspective of ensuring excellent capacity, when carbon derived from cellulose nanofibers and / or carbon derived from a water-soluble carbon material is supported on the surface of the particles of particle (A), cellulose nanofibers and / or a water-soluble carbon material may be added to slurry water i (or slurry water i') and / or slurry water ii in an amount such that the supported amount of the above carbon is achieved.

[0053] Next, the obtained slurry water ii is subjected to spray drying to obtain granulated product b. In spray drying, the operating conditions may be appropriately set according to the apparatus used. For example, as the processing conditions in a micro mist dryer (MDL-050M manufactured by Fujisaki Electric Co., Ltd.) equipped with a four-fluid nozzle, the hot air temperature is preferably 110°C to 300°C, more preferably 110°C to 180°C. Also, the volume ratio of the supply amount of hot air to the supply amount of slurry water (supply amount of hot air / supply amount of slurry water) is preferably 500 to 10,000, more preferably 1,000 to 9,000.

[0054] Step (III) is a step of firing the granulated product b obtained in step (II). The firing conditions of such step (III) are preferably in a reducing atmosphere or an inert atmosphere, the firing temperature is preferably 500°C to 1000°C, more preferably 550°C to 900°C, the firing time is preferably 0.5 hours to 12 hours, more preferably 1 hour to 6 hours.

[0055] The positive electrode active material particle mixture for a lithium ion secondary battery of the present invention is obtained by adjusting the particle (A) obtained through the above steps (I) to (III) to a predetermined content, and mixing such particle (A) with the above particle (B), particle (C), or other particles appropriately adjusted to a predetermined content according to a conventional method. Note that the above particle (B), particle (C), or other particles may be produced by a known method, for example, by the method described in the examples.

[0056] The positive electrode active material particle mixture for a lithium-ion secondary battery of the present invention can be applied as a positive electrode material to construct a lithium-ion secondary battery having a positive electrode, a negative electrode, an electrolytic solution, and a separator, or a positive electrode, a negative electrode, and a solid electrolyte as essential components. Specifically, for example, after preparing a positive electrode slurry by kneading a positive electrode active material particle mixture for a lithium-ion secondary battery with acetylene black, ketjen black, polyvinylidene fluoride, N-methyl-2-pyrrolidone, etc., it is applied to a current collector and then press-molded to produce a positive electrode. In the case of the positive electrode active material particle mixture for a lithium-ion secondary battery of the present invention, the above-mentioned particles (A) are appropriately disintegrated and are closely and effectively intertwined with other particles contained in the positive electrode active material particle mixture for a lithium-ion secondary battery and are mixed well and uniformly. For example, when the above-mentioned particles (B) or particles (C) are used as other particles, the disintegrated and refined particles (A) that coat these particles are scattered, and a positive electrode with high capacity and excellent storage characteristics and high usefulness can be obtained.

[0057] Here, regarding the negative electrode, as long as it can occlude lithium ions during charging and release them during discharging, its material composition is not particularly limited, and a material composition known in the art can be used. For example, carbon materials such as lithium metal, graphite, silicon-based (Si, SiOx), lithium titanate, or amorphous carbon can be used. And it is particularly preferable to use an electrode formed of an intercalation material that can electrochemically occlude and release lithium ions, especially a carbon material. Furthermore, two or more of the above-mentioned negative electrode materials may be used in combination. For example, a combination of graphite and silicon-based can be used.

[0058] The electrolytic solution is a solution in which a supporting salt is dissolved in an organic solvent. The organic solvent is not particularly limited as long as it is an organic solvent usually used in the electrolytic solution of a lithium-ion secondary battery. For example, carbonates, halogenated hydrocarbons, ethers, ketones, nitriles, lactones, oxolane compounds, etc. can be used.

[0059] The supporting salt is not particularly limited in terms of its type, but is preferably at least one selected from inorganic salts such as LiPF6, LiBF4, LiClO4, and LiAsF6, derivatives of the inorganic salts, organic salts such as LiSO3CF3, LiC(SO3CF3)2, and LiN(SO3CF3)2, LiN(SO2C2F5)2, and LiN(SO2CF3)(SO2C4F9), and derivatives of the organic salts.

[0060] The separator serves to electrically insulate the positive electrode and the negative electrode and hold the electrolytic solution. For example, a porous synthetic resin film, particularly a porous film of a polyolefin-based polymer (polyethylene, polypropylene), may be used.

[0061] The solid electrolyte serves to electrically insulate the positive electrode and the negative electrode and exhibits high lithium ion conductivity. For example, La 0.51 Li 0.34 TiO 2.94 、Li 1.3 Al 0.3 Ti 1.7 (PO4)3, Li7La3Zr2O 12 、50Li4SiO4·50Li3BO3, Li 2.9 PO 3.3 N 0.46 、Li 3.6 Si 0.6 P 0.4 O4, Li 1.07 Al 0.69 Ti 1.46 (PO4)3, Li 1.5 Al 0.5 Ge 1.5 (PO4)3, Li 10 GeP2S 12 、Li 3.25 Ge 0.25 P 0.75 S4, 30Li2S·26B2S3·44LiI, 63Li2S·36SiS2·1Li3PO4, 57Li2S·38SiS2·5Li4SiO4, 70Li2S·30P2S5, 50Li2S·50GeS2, Li7P3S 11 、Li 3.25 P 0.95 S4 may be used.

[0062] The shape of the lithium-ion secondary battery having the above configuration is not particularly limited, and it may be various shapes such as coin type, cylindrical type, square type, or an irregular shape enclosed in a laminate exterior body.

Examples

[0063] Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to these examples.

[0064] 《Measurement of average particle size of particles (secondary particles)》 The particle size distribution of the particles was measured using a laser diffraction apparatus (Microtrac MT3000II, manufactured by MicrotracBEL). The measurement conditions were as follows: particle permeability: transmission, particle shape: non-spherical, particle refractive index: 1.52. Ethanol was used as the solvent, and the solvent refractive index was 1.36.

[0065] 《Measurement of tap density (g / cm 3 )》 The tap bulk density was measured according to the method specified in JIS R 1628 "Method for Measuring Bulk Density of Fine Ceramics Powder", and this was taken as the tap density (g / cm 3 ).

[0066] 《Measurement of pore volume (mL / g)》 The pore volume of the particles was measured by mercury intrusion porosimetry using a mercury intrusion porosimeter (AutoPoreIV9520, manufactured by micrometritics). A sample cell for powder was used, and the measurement pressure range was from atmospheric pressure to 414 MPa. The pore volume in the pore diameter range of 10 nm to 3000 nm was determined from the obtained pore size distribution.

[0067] [Production Example 1: Production of Particles (A-1)] 1272 g of LiOH·H2O and 4 L of water were mixed to obtain slurry water xi. Next, while maintaining the temperature of the obtained slurry water xi at 25°C, 1153 g of an 85% phosphoric acid aqueous solution was dropped at a rate of 35 mL / min while stirring for 3 minutes, and then 1650 g of cellulose nanofiber (Cellish KY-100G, manufactured by Daicel Finechem Ltd., fiber diameter 4 nm to 100 nm) was added, and the mixture was stirred at a speed of 400 rpm for 12 hours to obtain slurry water yi containing Li3PO4. The obtained slurry water yi was purged with nitrogen to make the dissolved oxygen concentration of the slurry water yi 0.5 mg / L, and then 1610 g of MnSO4·5H2O and 834 g of FeSO4·7H2O were added to the entire amount of the slurry water yi to obtain slurry water zi. The molar ratio of the added MnSO4 to FeSO4 (manganese compound: iron compound) was 70:30.

[0068] Next, the obtained slurry water zi was put into an autoclave and subjected to a hydrothermal reaction at 180°C for 1 hour. The pressure inside the autoclave was 1.0 MPa. After the hydrothermal reaction, the generated crystals were filtered and then washed with 12 parts by mass of water with respect to 1 part by mass of the crystals. The washed crystals were freeze-dried at -50°C for 12 hours to obtain powder a1. 1000 g of the obtained powder a1 was taken, 12.2 g of ammonium carbonate (1.22 parts by mass with respect to 100 parts by mass of the powder a1) and 800 mL of water were added thereto to obtain slurry water zii. The obtained slurry zii was dispersed for 1 minute with an ultrasonic stirrer (T25, manufactured by IKA) to make the whole uniformly colored, and then spray-dried (nozzle air flow rate 40 L / min, supply air temperature 160°C) using a spray dryer (MDL-050M, manufactured by Fujisaki Electric Co., Ltd.) to obtain granule b1. The obtained granule b1 was fired at 700°C for 1 hour in an argon-hydrogen atmosphere (hydrogen concentration 3%) to obtain particles (A-1) (LiMn 0.7 Fe 0.3 PO4). The tap density of the obtained particles (A-1) was 0.3 g / cm 3 , the pore volume was 0.7 mL / g, the average particle diameter was 15 μm, and the carbon loading was 4.5% by mass.

[0069] [Production Example 2: Production of Particles (A-2)] Except that 15.2 g of ammonium carbonate added to powder a1 was used (1.52 parts by mass with respect to 100 parts by mass of powder a1), in the same manner as in Production Example 1, particles (A-2) (LiMn 0.7 Fe 0.3 PO4) were obtained. The tap density of the obtained particles (A-2) was 0.2 g / cm 3 , the pore volume was 0.8 mL / g, the average particle diameter was 15 μm, and the carbon loading was 4.5% by mass.

[0070] [Production Example 3: Production of Particles (A-3)] Except that 0.3 g of ammonium carbonate added to powder a1 was used (0.03 parts by mass with respect to 100 parts by mass of powder a1), in the same manner as in Production Example 1, particles (A-3) (LiMn 0.7 Fe 0.3 PO4) were obtained. The tap density of the obtained particles (A-3) was 1.0 g / cm 3 , the pore volume was 0.3 mL / g, the average particle diameter was 14 μm, and the carbon loading was 4.5% by mass.

[0071] [Production Example 4: Production of Particles (A-4)] Except that 0.06 g of ammonium carbonate added to powder a1 was used (0.006 parts by mass with respect to 100 parts by mass of powder a1), in the same manner as in Production Example 1, particles (A-4) (LiMn 0.7 Fe 0.3 PO4) were obtained. The tap density of the obtained particles (A-4) was 1.2 g / cm 3 , the pore volume was 0.2 mL / g, the average particle diameter was 13 μm, and the carbon loading was 4.5% by mass.

[0072] [Production Example 5: Production of Particles (A-5)] Except that 0.03 g of ammonium carbonate added to powder a1 was used (0.003 parts by mass with respect to 100 parts by mass of powder a1), in the same manner as in Production Example 1, particles (A-5) (LiMn 0.7 Fe 0.3 PO4) were obtained. The tap density of the obtained particles (A-5) was 1.4 g / cm 3The pore volume was 0.1 mL / g, the average particle size was 13 μm, and the carbon loading was 4.5 mass%.

[0073] [Production Example 6: Production of Particles (B-1)] 631 g of nickel sulfate hexahydrate, 126 g of cobalt sulfate heptahydrate, 51 g of aluminum sulfate, and 3 L of water were mixed so that the molar ratio of Ni:Co:Al became 80:15:5, and after heating to 60°C, a 20% aqueous sodium hydroxide solution heated to 60°C was added dropwise to such a mixed solution at a dropping rate of 300 mL / min to obtain a slurry containing a metal composite hydroxide with a pH of 10. Next, the obtained slurry was filtered and dried to obtain a mixture of metal composite hydroxides. Then, 132 g of lithium hydroxide monohydrate was mixed with such a mixture by a ball mill to obtain a powder mixture. The obtained powder mixture was calcined temporarily at 450°C for 6 hours in an air atmosphere and then crushed, and then calcined at 800°C for 12 hours in an air atmosphere as the main firing to obtain particles (B-1) (LiNi 0.8 Co 0.1 Al 0.1 O2, average particle size: 9 μm).

[0074] [Production Example 7: Production of Particles (C-1)] 473 g of nickel sulfate hexahydrate, 169 g of cobalt sulfate heptahydrate, 145 g of manganese sulfate pentahydrate, and 3 L of water were mixed so that the molar ratio of Ni:Co:Mn became 6:2:2. Then, 25% aqueous ammonia was added dropwise to such a mixed solution at a dropping rate of 300 mL / min to obtain a slurry containing a metal composite hydroxide with a pH of 11. Next, the obtained slurry was filtered and dried to obtain a mixture of metal composite hydroxides. Then, 111 g of lithium carbonate was mixed with such a mixture by a ball mill to obtain a powder mixture. The obtained powder mixture was calcined temporarily at 800°C for 4 hours in an air atmosphere and then crushed, and then calcined at 800°C for 11 hours in an air atmosphere as the main firing to obtain particles (C-1) (LiNi 0.6 Co 0.2 Mn 0.2 O2, average particle size: 10 μm).

[0075] [Production Example 8: Production of Particles (D-1)] Powders of 222 g of lithium carbonate and 482 g of cobalt oxide were mixed with a ball mill so that the molar ratio of Li:Co became 1:1, and a powder mixture was prepared. The obtained powder mixture was compacted at a molding pressure of 500 kg / cm 3 and calcined at 700 °C for 5 hours in an air atmosphere. Next, this molded body was pulverized and mixed again, and after being compacted at a molding pressure of 1000 kg / cm 3 it was fired at 900 °C for 10 hours in an air atmosphere to obtain particles (D-1) (LiCoO2, average particle size: 8 μm).

[0076] [Examples 1 to 7, Comparative Examples 1 to 4] According to the formulations shown in Tables 1 to 3, predetermined particles were mixed using a pestle and mortar to obtain a positive electrode active material particle mixture. Next, a lithium-ion battery was fabricated according to the following method, and the battery characteristics were measured and evaluated. The results are shown in Tables 1 to 3.

[0077] 《Battery Characteristics of Lithium-Ion Batteries》 Each of the obtained positive electrode active material particle mixtures was used as a positive electrode material to fabricate a positive electrode of a lithium-ion secondary battery. Specifically, each of the obtained positive electrode active material particle mixtures, Ketjen black, and polyvinylidene fluoride were mixed at a mixing ratio of 90:5:5 by mass, and N-methyl-2-pyrrolidone was added thereto and kneaded thoroughly to prepare a positive electrode slurry. The positive electrode slurry was applied to a current collector made of an aluminum foil with a thickness of 20 μm using a coater, and vacuum dried at 80 °C for 12 hours. Then, it was pressed at 20 kN using a roll press and punched into a disk shape with a diameter of 14 mm to obtain a positive electrode.

[0078] Next, a coin-type secondary battery was constructed using the above positive electrode. As the negative electrode, a lithium foil punched out to φ15 mm was used. As the electrolytic solution, a solution in which LiPF6 was dissolved at a concentration of 1 mol / L in a mixed solvent obtained by mixing ethylene carbonate and ethyl methyl carbonate at a volume ratio of 3:7 was used. As the separator, a polymer porous film was used. These battery components were incorporated and housed by a conventional method in an atmosphere with a dew point of -50°C or lower to obtain a coin-type secondary battery (CR-2032).

[0079] Using the obtained coin-type secondary battery, the discharge capacity at 0.2C (34 mAh / g) in an environment with an air temperature of 30°C was measured with a discharge capacity measuring device (HJ-1001SD8, manufactured by Hokuto Denko Corporation). Also, the electrode density was calculated by the following formula (x). Electrode density (g / cm 3 ) = Mass of the positive electrode active material particle mixture in the positive electrode (mg) / Electrode volume (φ14 mm × thickness (μm)) ···(x) Furthermore, the obtained coin-type secondary battery was charged at a constant current of 0.2C (34 mA / g) and an upper limit voltage of 4.3V in an environment with an air temperature of 30°C, and then the discharge capacity after storage at 55°C for 7 days was measured in the same manner as above, and the capacity retention rate (%) was determined with the discharge capacity at 0.2C (34 mAh / g) in the measured environment with an air temperature of 30°C taken as 100%.

[0080]

Table 1

[0081]

Table 2

[0082]

Table 3

Claims

1. The following formula (A): LiaMnbFecM1xPO4...(A) (In formula (A), M1 represents Mg, Al, Ti, Cu, Zn, Nb, Co, Ni, Ca, Sr, Y, Zr, Mo, Ba, Pb, Bi, La, Ce, Nd or Gd. a, b, c, and x satisfy 0 < a ≤ 1.2, 0 ≤ b ≤ 1.2, 0 ≤ c ≤ 1.2, 0 ≤ x ≤ 0.3, and b + c ≠ 0, and represent numbers that satisfy a + (valence of Mn)×b + (valence of Fe)×c + (valence of M1)×x = 3.) Particles (A) represented by the formula, having a tap density of 0.3 g / cm3 to 1.2 g / cm3, and having a pore volume of 0.2 mL / g to 0.7 mL / g in a pore diameter of 10 nm to 3000 nm A method for producing a positive electrode active material particle mixture for a lithium-ion secondary battery, containing 10% by mass or more of the above, comprising the following steps (I) to (III): (I) A step of subjecting slurry water i obtained by mixing a lithium compound, a metal compound containing a manganese compound and / or an iron compound, a phosphoric acid compound, and water, or slurry water i' obtained by mixing lithium phosphate particles, a metal compound containing a manganese compound and / or an iron compound, and water to a hydrothermal reaction to obtain powder a (II) A step of spray-drying slurry water ii obtained by adding and mixing the obtained powder a, 0.01 part by mass to 0.3 part by mass of ammonium carbonate with respect to 100 parts by mass of powder a, and water to obtain granulated body b (III) A step of firing the obtained granulated body b A method for producing a positive electrode active material particle mixture for a lithium-ion secondary battery, which comprises mixing particles (A) obtained by a production method in which slurry water i or slurry water i' in step (I), or slurry water ii in step (II) further contains cellulose nanofibers and / or a water-soluble carbon material

2. Furthermore, the method for producing a positive electrode active material particle mixture for a lithium-ion secondary battery according to claim 1, further comprising mixing particles (B) represented by the following formula (B): LiNi d Co e Al f M 2 y O 2 ... (B) (In formula (B), M 2 represents one or more elements selected from Mg, Ti, Nb, Fe, Cr, Si, Ga, V, Zn, Cu, Sr, Mo, Zr, Sn, Ta, W, La, Ce, Pb, Bi, and Ge. d, e, f, y satisfy 0.4 ≦ d < 1, 0 < e ≦ 0.6, 0 < f ≦ 0.3, 0 ≦ y ≦ 0.3, and 3d + 3e + 3f + (the valence of M 2 ) × y = 3.) (No specific formula (B) content is provided in the original text, so it remains untranslated here)

3. The method for producing a positive electrode active material particle mixture for a lithium-ion secondary battery according to claim 2, wherein the content of particles (B) in the positive electrode active material particle mixture for a lithium-ion secondary battery is 50% by mass to 80% by mass

4. The method for producing a positive electrode active material particle mixture for a lithium ion secondary battery according to claim 2 or 3, wherein the average particle diameter of the particles (A) is 6 μm to 20 μm and the average particle diameter of the particles (B) is 4 μm to 13 μm.

5. Furthermore, the following formula (C): LiNi g Co h Mn i M 3 z O 2 ... (C) (In formula (C), M 3 represents one or more elements selected from Mg, Ti, Nb, Fe, Cr, Si, Al, Ga, V, Zn, Cu, Sr, Mo, Zr, Sn, Ta, W, La, Ce, Pb, Bi, and Ge. g, h, i, and z are numbers satisfying 0.3 ≤ g < 1, 0 < h ≤ 0.7, 0 < i ≤ 0.7, 0 ≤ z ≤ 0.3, and 3g + 3h + 3i + (the valence of M 3 ) × z = 3.) The method for producing a positive electrode active material particle mixture for a lithium ion secondary battery according to any one of claims 2 to 4, wherein particles (C) represented by are mixed.

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