JP5634828B2 - Manufacturing method and use of spinel type lithium manganese composite oxide particles - Google Patents

Description

  The present invention provides a spinel type lithium manganese having a small specific surface area, a high particle density and a high packing density of particles, a uniform lattice constant, a high compressive elastic modulus, and a small fluctuation range of the compressive elastic modulus for each particle. The composite oxide particles and the production method thereof, and the above-mentioned particle characteristics do not damage the current collector substrate during the formation of the electrode film. The present invention relates to a lithium ion secondary battery having little elution of Mn when used, high charge / discharge capacity, and excellent cycle characteristics.

  As a positive electrode material for lithium ion batteries, lithium cobaltate, lithium nickelate, lithium manganate, etc. have been put into practical use, and research and development are being promoted aiming at high performance.

  Among these, lithium cobaltate has a problem that the raw material cobalt is expensive and the effective storage amount is only about 50% of the theoretical amount. Lithium nickelate is also attracting attention because it is inexpensive and has an effective storage capacity that is about 1.4 times that of lithium cobaltate. However, it is difficult to synthesize and has a problem with safety. On the other hand, lithium manganate is slightly inferior to lithium cobaltate in effective storage capacity, but it is expected to be a positive electrode material for lithium ion batteries because the raw material manganese is cheap and its storage and safety are equivalent to lithium cobaltate. Has been.

  These positive electrode materials are mixed in an organic solvent together with a carbon-based conductive agent such as graphite and a binder into a paste mixture, and this is applied to a 15 to 20 μm aluminum foil with a uniform thickness. Next, after drying, the density of the mixture is increased and the electrode is compressed with a press to make the electrode thickness uniform, whereby a positive electrode for a battery is produced. This positive electrode is loaded into a battery container together with a negative electrode, a separator, etc., and the battery is configured. However, filling as much positive electrode material as possible into a certain volume of battery improves battery performance such as charge capacity or discharge capacity. Preferred in terms. For this purpose, the amount of the positive electrode material in the mixture may be increased, but the amount of the positive electrode material that can be blended in the mixture is also limited. Therefore, if a positive electrode material with fine particles as fine as possible is used, the packing density is large, so that the weight of the positive electrode material filled per unit volume increases and a battery with a high discharge capacity can be obtained. That is, as a positive electrode material, a high discharge capacity per unit volume (discharge capacity per unit weight x packing density of positive electrode material fine particles) is also an important factor of the positive electrode material.

  However, the lithium manganate fine particles conventionally used as the positive electrode material have a smaller packing density when compared with the lithium cobalt oxide fine particles having the same particle diameter. Therefore, when comparing positive electrode materials of the same volume, the discharge capacity per weight can be expected to be about 80% of lithium cobalt oxide, but there is a problem that the discharge capacity per volume is as low as about 50 to 60%. Furthermore, in a battery using conventional lithium manganate as a positive electrode material, there is a problem of deterioration in cycle characteristics in that the discharge capacity gradually decreases as charging and discharging are repeated.

  In order to solve these problems, a lithium-manganese composite oxide in which a third component such as B is added to lithium manganate has been proposed (JP-A-4-237970: Patent Document 1). JP-A-5-290846: Patent Document 2, JP-A-8-195200: Patent Document 3).

  JP-A-11-71115 (Patent Document 4) contains at least one other element other than Li and Mn, and consists of a spinel structure lithium / manganese oxide with little Mn elution in an organic solvent. A positive electrode active material (hereinafter sometimes referred to as a positive electrode material) is disclosed.

  As a manufacturing method of the positive electrode material at this time, manganese dioxide particles having an average agglomerated particle diameter of 0.5 to 50 μm are used as manganese compounds, and after mixing and granulating other kinds of elemental compounds at 500 to 1000 ° C. A method of firing is disclosed. At this time, it is recommended to use a rotary kiln as a method of mixing raw materials uniformly and performing granulation and firing.

  However, in the method of mixing and firing manganese dioxide particles having an average agglomerated particle diameter of 0.5 to 50 μm and other kinds of element compounds in a rotary kiln, the mixing is not microscopically uniform, and the composition of the resulting particles, the lattice constant, Fluctuations in particle density, etc. are large and non-uniform. In addition, it is difficult to make the firing temperature uniform regardless of the continuous type or batch type, and the density, specific surface area, and crystal of the resulting spinel lithium manganese oxide particles When the primary particle diameter and the like of the child system fluctuate and are used as the positive electrode material, it is difficult to maintain high performance or the performance may fluctuate, and further improvement has been demanded.

  Furthermore, the applicant of the present application disclosed in Japanese Patent Application Laid-Open No. 11-171551 (Patent Document 5) includes an oxide containing B (boron) or V (vanadium) and having a melting point of 800 ° C. or less, and has a crystal grain size of about Disclosed are lithium-manganese composite oxide particles that are in the range of 0.1 to 5.0 μm, sintered and have an average particle diameter of 2 to 30 μm, and a method for producing the same.

  As a production method, specifically, a water suspension in which a lithium compound, manganese dioxide particles, and an oxide having a melting point of 800 ° C. or less are mixed so as to have a predetermined composition range is dried by spray drying or the like, and then a rotary kiln or the like. Baking at 650-900 ° C. At this time, it is described that the raw material manganese dioxide particles are preferably adjusted in advance by wet pulverization or the like so that the average particle diameter is in the range of 0.1 to 5 μm. Patent Document 5 describes that the solid content concentration of the aqueous suspension (mixed slurry) is preferably 10 to 30% by weight.

JP-A-4-237970 Japanese Patent Laid-Open No. 5-290846 JP-A-8-195200 JP-A-11-71115 JP-A-11-171551

  In the batteries described in Patent Documents 1 to 3, however, batteries using these lithium / manganese composite oxides as the positive electrode material still have the problem of low cycle characteristics when used at a temperature higher than room temperature. Yes.

  Further, in the method described in Patent Document 4, in the method in which manganese dioxide particles having an average aggregated particle size of 0.5 to 50 μm and other kinds of element compounds are mixed and fired in a rotary kiln, the mixing is not microscopically uniform. Fluctuations in the composition, lattice constant, particle density, etc. of the resulting particles are greatly non-uniform, and in addition, it is difficult to make the firing temperature uniform regardless of the continuous type or batch type, and the resulting spinel structure lithium manganese oxide Particle density, specific surface area, crystallite system The primary particle diameter, etc. fluctuate. When used as a positive electrode material, it may be difficult to maintain high performance, and performance may fluctuate, further improving. It was requested.

  Further, according to the method of Cited Document 5, the water suspension has coarse particles, or fine particles aggregate to become coarse particles, or there are particles that settle due to changes over time, and spray-dried and fired. The composition, density, specific surface area, lattice constant, etc. of the particles obtained in this way change over time and become non-uniform, resulting in insufficient discharge capacity and cycle characteristics when used as a positive electrode material.

  Further, due to the change over time of the aqueous suspension, there are concave portions in the particles obtained by spray drying, or bowl-like particles are present, and the particle density of the particles obtained by firing this at high temperature However, when used as a positive electrode material, there is a problem that discharge capacity, cycle characteristics and the like are insufficient.

  Under such circumstances, the present inventors diligently studied the above problems, and as a result, mixed lithium compound, manganese dioxide particles, alumina sol and boric acid so as to be within a predetermined composition range, and adjusted pH to a predetermined range. Then, the yield stress value of the aqueous suspension falls within a predetermined range, that is, the manganese dioxide particles are loosely aggregated together with other components in the aqueous suspension to form an overall three-dimensional gel structure. Can suppress aggregation, particle coarsening, and particle sedimentation due to the above-mentioned change over time, and there is no change over time, the particle density is high, the fluctuation range of the lattice constant is small, and the change in compression modulus The inventors have found that lithium-manganese composite oxide particles having a small coefficient can be obtained, and have completed the present invention.

That is, the gist of the present invention is as follows.
[1] A process for producing spinel-type lithium / manganese composite oxide particles comprising the following steps (a) to (c);
(A) Lithium compound (lithium hydroxide), manganese dioxide particles (A) having an average primary particle diameter (D ₁ ) in the range of 0.1 to ₁ μm, alumina sol, and boron compound, Li: Mn: Al: B The atomic ratio is (x + y) :( 2-y−z): z1: z2 (where x = 1.0 to 1.2, 0 <y ≦ 0.2, 1 <x + y ≦ 1.2, z1 (Al ) = 0.01 to 0.2, z2 (B) = 0.005 to 0.05, z = z1 + z2), and the solid content concentration is in the range of 5 to 50% by weight. A step of preparing a spray dispersion mixture dispersion having a yield stress value of 5 to 500 Pa and a pH of 9 to 14.
(B) A step of spray drying.
(C) A step of firing.

[2] The method for producing spinel-type lithium / manganese composite oxide particles according to [1], wherein the following step (d) is further performed following the step (c);
(D) A step of crushing so that the average particle size (D ₃ ) is in the range of 10 to 20 μm and the particle size distribution is 2 to 40 μm.
[3] The method for producing spinel type lithium / manganese composite oxide particles according to [1] or [2], wherein the manganese dioxide particles (A) in the step (a) have a zeta potential in the range of −60 to −5 mV.
[4] The ratio of CBD to ABD is such that the filling bulk density (ABD) is in the range of 1.0 to 1.6 g / ml and the compressed packing density (CBD) is in the range of 1.5 to 2.1 g / ml. A process for producing spinel type lithium / manganese composite oxide particles according to [1] to [3], wherein CBD / ABD is in the range of 1.1 to 1.8.

[5] Spinel of [1] to [4] having a 10% compression modulus in the range of ²⁰ to 200 kgf / mm ² and a coefficient of variation (CV value) of the 10% compression modulus in the range of 5 to 30% Method of manufacturing type lithium / manganese composite oxide particles.
[6] Spinel-type lithium / manganese composite oxide particles represented by the following general formula, having a specific surface area of 0.1 to 2.0 m ² / g and an average particle diameter (D ₃ ) of 10 In the range of ˜20 μm, particle size distribution in the range of 2 to 40 μm, packing bulk density (ABD) in the range of 1.0 to 1.6 g / ml, and compression packing density (CBD) of 1.5. in the range of ~2.1g / ml, in the range of the ratio CBD / ABD between CBD and ABD is 1.1 to 1.8, the lattice constants are in the range of 8.15000 to 8.25000 Å, the The standard deviation of the lattice constant is 0.00092 angstrom or less, the 10% compression modulus is in the range of ²⁰ to 200 kgf / mm ² , and the coefficient of variation (CV value) of the 10% compression modulus is in the range of 5 to 30%. Lithium Ma characterized by Cancer composite oxide particles.
Li _{(x + y)} Mn _(2-yz) M _z O ₄
(However, x = 1.0 to 1.2, 0 <y ≦ 0.2, 1 <x + y ≦ 1.2, M is Al and B, z1 (Al) = 0.01 to 0.2, z2 (B) = 0.005 to 0.05)
[7] The lithium / manganese composite oxide particles according to [6] produced by the method for producing spinel-type lithium / manganese composite oxide particles according to [1] to [5].
[8] A lithium ion secondary battery using spinel-type lithium / manganese composite oxide particles produced by the production method of [1] to [5] as a positive electrode material.

  According to the present invention, spherical lithium / manganese composite oxide fine particles can be obtained. When such particles are used as a positive electrode material, the aluminum foil is not damaged when applied, and when used as a positive electrode material, a current collector substrate containing a metal foil such as an aluminum foil is damaged. Also, at this time, there is no destruction of the particles even if pressure bonding is performed. As a result, a lithium ion secondary battery having a high discharge capacity per volume and excellent cycle characteristics when used at high temperatures can be provided.

First, a method for producing spinel-type lithium / manganese composite oxide particles according to the present invention will be described.
Method for Producing Spinel Type Lithium / Manganese Composite Oxide Particles The method for producing spinel type lithium / manganese composite oxide particles according to the present invention comprises the following steps (a) to (c).

[(A) Dispersion preparation step]
First, (a) a lithium compound (lithium hydroxide), manganese dioxide particles having an average primary particle diameter (D ₁ ) in the range of 0.1 to ₁ μm, an alumina sol, and a boron compound are converted into atoms of Li: Mn: Al: B. The ratio is (x + y) :( 2-y−z): z1: z2 (where x = 1.0 to 1.2, 0 <y ≦ 0.2, 1 <x + y ≦ 1.2, z1 (Al) = 0.01 to 0.2, z2 (B) = 0.0005 to 0.05, z = z1 + z2), and the solid content concentration is in the range of 5 to 50 wt%. A mixture dispersion for spray drying having a yield stress value in the range of 5 to 500 Pa and a pH in the range of 9 to 14 is prepared.

Manganese dioxide particles As the manganese dioxide particles used in the present invention, electrolytic manganese dioxide powder and chemically synthesized manganese dioxide powder are usually used. Further, manganese compounds such as manganese hydroxide, manganese carbonate, manganese nitrate, etc. which are thermally decomposed to become manganese dioxide, or a mixture thereof can be used.

  In the present invention, electrolytic manganese dioxide powder is preferably used, but if used as it is, the particle size is large, spinel crystallization is not efficiently performed even when heat-treated at high temperature, and may remain as manganese dioxide. The charge / discharge capacity and cycle characteristics may be insufficient.

Usually, the electrolytic manganese dioxide powder is used after being pulverized, but the average primary particle diameter (D ₁ ) of the pulverized manganese dioxide particles (A) is in the range of 0.1 to ₁ μm, more preferably 0.2 to 0.8 μm. It is preferable.

Here, the average primary particle diameter of the manganese dioxide particles (A) means a particle diameter measured in a state without aggregation immediately after irradiation with ultrasonic waves in the measurement of the particle diameter.
In addition, said average primary particle diameter is the value measured using the ultrasonic irradiation apparatus (Horiba Seisakusho: LA-950v2).

When the average primary particle diameter (D ₁ ) of the manganese dioxide particles is small, in the mixture mixture for spray drying composed of lithium compound (lithium hydroxide), alumina sol, boron compound and manganese dioxide particles (A), manganese dioxide particles (A ) (Described later) may be lower than −60 mV (that is, the negative charge increases), and the yield stress value may be higher than 500 Pa. In this case, the spray-drying mixture dispersion may be a hard pudding. In this state, spray drying becomes difficult, and even if spray drying is possible, it is difficult to uniformly dry, and it is difficult to obtain dense and spherical spinel type lithium / manganese composite oxide particles.

  In addition, the density of the spinel-type lithium / manganese composite oxide particles tends to fluctuate and tend to decrease, and the fluctuation range of the lattice constant may increase. When such particles are used as a positive electrode material, The strength, density, etc. of the electrode may decrease, and the discharge capacity, cycle characteristics, etc. may be insufficient.

If the average primary particle diameter (D ₁ ) of the manganese dioxide particles (A) is too large, the manganese dioxide primary particles in the spray dispersion mixture dispersion comprising lithium hydroxide, alumina sol, boric acid and manganese dioxide particles (A) The zeta potential (surface charge amount) exceeds -5 mV. As a result, the colloidal properties are insufficient and the repulsive force between the particles is reduced, so that the manganese dioxide primary particles easily aggregate and become coarse agglomerated particles over time. When such a spray-drying mixture dispersion is spray-dried, Further, firing at a higher temperature is required, and when firing at a higher temperature, the elution of Mn may increase due to an increase in lattice defects. In addition, the obtained spinel type lithium / manganese composite oxide particles have a low particle density, a large fluctuation range of the lattice constant, a low compressive modulus, and a large coefficient of variation of the compressive modulus. The secondary battery may have insufficient charge / discharge capacity and cycle characteristics.

Lithium compound Examples of the lithium compound used in the present invention include lithium hydroxide, lithium carbonate, lithium nitrate, lithium acetate, and lithium oxide. Among these, lithium hydroxide and lithium carbonate can be preferably used.

Alumina sol In the present invention, Al is used as the first element other than Li and Mn. In the preparation process of the present invention, alumina sol (Al ₂ O ₃ .nH ₂ O) is used as the Al compound.

The alumina (hydrate) particles in the alumina sol are generally fibrous primary particles or secondary particles in which they are bundled.
The average primary particle diameter of the alumina particles is preferably in the range of 5 to 50 nm, more preferably 10 to 30 nm.

  If the average primary particle size is in the above range, a large amount of alumina (hydrate) particles adhere to or adsorb to the manganese dioxide primary particles (A), and the zeta potential of the manganese dioxide particles (A) decreases, resulting in an aqueous suspension. The manganese dioxide particles are loosely agglomerated together with other components to take a three-dimensional gel structure as a whole, and the yield stress value is within a predetermined range. Aggregation due to aging, coarsening of the particles, and further Settling can be suppressed.

  If the average primary particle size of the alumina (hydrate) particles is small, the alumina (hydrate) particles are aggregated and the composition distribution of the spinel-type lithium / manganese composite oxide particles finally obtained becomes non-uniform. There is a case.

  If the average primary particle size of the alumina (hydrate) particles is too large, the zeta potential will increase because the amount of adhesion to the manganese dioxide particles (A) will decrease (that is, the negative charge is small, and in some cases it becomes a positive charge). ) And the colloidal properties become insufficient, the repulsive force between the particles becomes small, and the yield stress value of the dispersion becomes small. For this reason, the primary particles of manganese dioxide aggregate easily and become coarse aggregated particles with time, and if the mixture dispersion for spray drying is spray dried and baked at a high temperature, the lattice defects may increase. Elution may increase, and the resulting spinel-type lithium-manganese composite oxide particles have a low particle density, a large variation in lattice constant, a low compression modulus, and a large coefficient of variation in compression modulus. Secondary batteries using such particles may have insufficient charge / discharge capacity and cycle characteristics.

  For the average primary particle size, a transmission electron micrograph (TEM) of alumina hydrate fine particles was taken, the width and length of 100 particles were measured, and ½ of the sum of the width and length was the primary particle. And the average value.

The average secondary particle diameter of the alumina (hydrate) secondary particles is preferably 1,000 nm or less, more preferably 800 nm or less.
If the average secondary particle size of the alumina (hydrate) secondary particles is too large, the dispersibility of the alumina particles will be insufficient, and in addition, the mixed state with the manganese dioxide primary particles (A) will become non-uniform, resulting in a final The composition distribution of the spinel-type lithium-manganese composite oxide particles obtained is uneven, and in this case, the doping of Al may be insufficient, and the effects of using Al, that is, the suppression of crystal structure transition, lattice defects Insufficient suppression of the production of Mn, thus increasing the elution of Mn, resulting in insufficient discharge and charge capacity and cycle characteristics.

  The average secondary particle size of the alumina (hydrate) secondary particles is diluted by adding ion exchange water to alumina sol (alumina hydrate fine particle dispersion) to prepare a dispersion having a solid content concentration of 0.5% by mass. The particle size distribution was measured by a dynamic scattering method (Otsuka Electronics Co., Ltd .: PAR-III).

Boron Compound In the present invention, B is used as the second element other than Li and Mn. As the compound of B, boric acid, borate, boron oxide or the like can be used.

When such a boron compound is used, it becomes an oxide (B ₂ O ₃ ) at a relatively low temperature when fired in the step (c) described later, and since the melting point is low, B ₂ O ₃ is formed in the spinel crystal formation process. Acts as a flux, promotes the formation and growth of spinel crystals, further promotes the sintering of the spinel crystal particles, and can provide spinel-type lithium / manganese composite oxide particles having a low specific surface area. It is possible to suppress side reactions such as decomposition of the electrolyte on the particle surface that occur when used as a catalyst. At the same time, spinel-type lithium / manganese composite oxide particles having a high particle density can be obtained, and when used as a positive electrode active material, the charge / discharge capacity per unit volume is high and the cycle characteristics are excellent.

Compounds of Elements Other than Al and B In the present invention, Na, Be, Mg, Ca, Sr, Ba, Sc, Y, Ti, Zr, V, Nb, Ta, Cr, Mo are used as the elements other than Al and B described above. , W, Fe, Co, Ni, Cu, Ag, Zn, Ga, In, Si, Ge, Sn, Pb, P, As, Sb, Bi, La, and the like may be included. (A) Step Then, such elemental compounds can be used in combination. As the compound, inorganic acid salts, organic acid salts, chelates and the like are used.

    In the step (a), the manganese dioxide particles (A), the lithium compound, the alumina sol, and the boron compound are mixed with a Li: Mn: Al: B atomic ratio of (x + y) :( 2-yz): z1: z2. (However, x = 1.0 to 1.2, 0 <y ≦ 0.2, 1 <x + y ≦ 1.2, z1 = 0.01 to 0.2, z2 = 0.005 to 0.05, z = Z1 + z2) to prepare a spray-drying mixture dispersion having a solid content in the range of 5 to 50% by weight.

When the amount of the above elements is expressed by the general formula Li _{(x + y)} Mn _(2-yz) M _{(z1 + z2)} O ₄ , z1 is 0.01 to 0.2, preferably 0.02 to 0. .18, and z2 is selected from the range of 0.0005 to 0.05, preferably 0.001 to 0.04.

  If the atomic ratio z1 of Al is within the above range, the generation of lattice defects can be suppressed, and the elution of Mn can be suppressed. Therefore, the spinel-type lithium / manganese composite oxide particles having excellent discharge capacity and cycle characteristics Can be obtained.

  When the atomic ratio z1 of Al is smaller than the lower limit, the suppression of crystal structure transition, the generation of lattice defects, and the suppression of elution of Mn are insufficient, and such spinel type lithium / manganese composite oxide particles were used. In some cases, the charge / discharge capacity and cycle characteristics may be insufficient.

If the atomic ratio z1 of Al exceeds the above upper limit, the Mn content decreases, so that when used as a positive electrode material, the charge / discharge capacity per unit weight tends to decrease.
If the atomic ratio z2 of B is in the above range, the generation and growth of spinel-type lithium / manganese composite oxide particles are promoted, and further, the sintering of the spinel-type lithium / manganese composite oxide particles is promoted. Spinel-type lithium / manganese composite oxide particles having a low surface area can be obtained, and side reactions such as decomposition of the electrolyte on the particle surface when used as a positive electrode active material can be suppressed. At the same time, spinel-type lithium / manganese composite oxide particles having a high particle density can be obtained, and when used as a positive electrode active material, the charge / discharge capacity per unit volume is high and the cycle characteristics are excellent.

  The amount of Li (x + y) in the spinel type lithium / manganese composite oxide particles according to the present invention is selected from the range of 1.0 to 1.2 in the above general formula. The theoretical amount of Li in the spinel-type lithium-manganese composite oxide used as the positive electrode material of the lithium ion battery is 1, that is, (x + y) = 1 (y = 0). At this time, it is considered that Mn is substituted only for the element (M). When Li exceeds the theoretical amount of 1 [(x + y)> 1], if the amount of Mn is reduced by an amount corresponding to a part or all of the excess amount (y), a part or all of the excess Li is elemental (M ) And the like, and is considered to have a structure substituted with Mn. The substitution amount at this time is 0 <y ≦ 0.2.

The solvent used in the dispersion is not particularly limited as long as it is volatile, but usually water, lower alcohols and the like are used, preferably water.
The concentration of the spray-drying mixture dispersion having such a composition is preferably in the range of 5 to 50% by weight, more preferably 10 to 40% by weight as the solid content.

 If the concentration of the mixture dispersion for spray drying is too low, the production efficiency will be low, and even if the concentration of the mixture dispersion for spray drying is too high, the particles obtained by spray drying may have recesses, Particles are present, and the particle density of the particles obtained by firing at high temperature is likely to fluctuate, and when used as a positive electrode material, the strength, density, etc. of the electrode may decrease, and the discharge capacity, In some cases, the cycle characteristics were insufficient.

In the present invention, the yield stress value of the spray-drying mixture dispersion is adjusted to a range of 5 to 500 Pa, preferably 10 to 400 Pa.
In the present invention, manganese dioxide particles having a particle diameter in a predetermined range have a predetermined amount of surface charge on the surface due to the presence of alumina sol, and as a result, the manganese dioxide particles (A) loosely aggregate and disperse. It is considered that the liquid forms a three-dimensional gel structure.

  When a shear stress is applied to a dispersion having such a three-dimensional gel structure at a constant frequency, initially the elastic modulus (storage elastic modulus and loss elastic modulus) is maintained at a substantially constant value, and the properties as an elastic body are maintained. As shown, when the stress is increased, the elastic modulus rapidly decreases at a certain stress. That is, there is a yield stress value.

  In the present invention, paying attention to the yield stress value of the dispersion having a three-dimensional gel structure, if this value is adjusted to a predetermined range, the change over time of the dispersion over time from preparation of the dispersion to spray drying, that is, Aggregation, coarsening of particles, and sedimentation of particles can be suppressed, and spray drying can be performed under the same conditions as in preparation. As a result, it is possible to obtain a lithium-manganese composite oxide having a high particle density, a small variation range of the lattice constant of the crystal, and a small coefficient of variation of the compressive modulus.

  Usually, it is considered that the particles are not easily settled if the particles are interacting with each other, and the present invention adopts the yield value as one measure. Usually, the dispersion has a large change over time due to the influence of sedimentation and the like. In order to reduce this change over time, spray drying may be considered immediately after preparation, but this only has a solution to increase spray drying capacity or repeat dispersion preparation on a small scale. It is difficult to control the particle diameter, and the latter has poor production efficiency, and also has various variations in properties from preparation to preparation. In such a method, the lattice constant of the obtained spinel-type lithium / manganese composite oxide particles is likely to be affected, and fluctuations in the lattice constant also have a large effect on battery performance, which increases non-standard products. There is also. However, the present inventors have found a problem associated with such a change with time, and according to the present invention, such a problem can be solved without dealing with such a change with time.

  If the yield stress value is low, the particle components in the dispersion mixture for spray drying easily settle, and the physical properties such as the particle components obtained by spray drying, the distribution of the components, the lattice constant and the particle diameter may vary. is there. If the yield stress value is too high, spray drying may be difficult.

The yield stress value can be measured under the condition of f (frequency) = 1.0 Hz using a viscosity / viscoelasticity measuring apparatus (manufactured by Eiko Seiki Co. , Ltd .: trade name, Rheo Stress RS600).
The pH of the spray-drying mixture dispersion is preferably in the range of 9 to 14, more preferably 11 to 13.

  When the pH of the mixture dispersion for spray drying is less than 9, the alumina sol and boron compound may be present as poorly soluble compounds, and the component distribution of particles obtained by spray drying may become non-uniform. When adjusting the pH as necessary, it is preferable to use a basic compound such as ammonia or amines that does not finally remain in the particles.

  If the pH of the spray-drying mixture dispersion is within the above range, the yield stress value of the spray-drying mixture dispersion is approximately within the above range, and the dispersibility of the components present in the spray-drying mixture dispersion is sufficient, Aggregation, sedimentation, etc. are suppressed, compositional change over time is suppressed, the component distribution of particles obtained by spray drying is uniform, and the specific surface area of the spinel-type lithium / manganese composite oxide particles finally obtained, Quality fluctuations such as particle density are suppressed, and a lithium ion secondary battery having excellent performance such as manganese elution amount, charge / discharge capacity, cycle characteristics and the like and small fluctuations can be obtained.

The zeta potential of the manganese dioxide particles (A) in the mixture dispersion for spray drying is preferably in the range of −60 to −5 mV, more preferably −40 to −10 mV.
When the zeta potential of the manganese dioxide particles (A) is lower than -60 mV (the negative charge becomes stronger), the surface potential difference from the alumina hydrate particles becomes large, and the alumina hydrate on the surface of the manganese dioxide particles (A). The particles are completely separated without adhering or adsorbing, and the component distribution of the particles obtained by spray drying becomes non-uniform.
In the present invention, the zeta potential was measured using an ultrasonic particle size distribution analyzer (manufactured by Dispersion Technology: DT-1200).

  The mixture dispersion for spray drying may be prepared by mixing lithium compound, alumina sol and boron compound with manganese dioxide particle dispersion whose particle size distribution has been adjusted in advance. Preferably, manganese dioxide particles, lithium compound, alumina sol and boron are mixed. It is desirable to prepare by mixing and then grinding the compound.

  The pulverization can be performed without any particular limitation using a pulverizer using a medium such as beads, and the bead diameter is preferably 0.05 to 5 mmφ, more preferably 0.1 to 45 mmφ. If the bead diameter is within this range, the above-mentioned range average particle diameter (primary, secondary) and particle diameter distribution can be adjusted.

  The treatment time is preferably in the range of 5 minutes to 5 hours, more preferably 10 minutes to 3 hours. When the treatment time is in the above range, manganese dioxide particles (A) having a predetermined average particle size and particle size distribution of the present invention can be obtained.

Further, for example, first, after pulverizing with large-diameter beads, pulverizing with small-diameter beads sequentially, a more uniform particle size distribution can be obtained.
Such a spray-drying mixture dispersion is spray-dried. In addition, if it is less than 10 hours after preparation, the said dispersion liquid physical property will not change a lot. More preferably, it is desirable to perform spray drying within 8 hours. In addition, since the properties of conventional dispersions change in a short time, it was necessary to perform spray drying in a short time after preparation. In the present invention, as described above, a specific yield stress value is required. Therefore, it looks like a gel and there is little such change with time.

The concentration of the spray-drying mixture dispersion having such a composition is preferably in the range of 5 to 50% by weight, more preferably 10 to 40% by weight as the solid content.
When the solid content concentration of the spray dispersion mixture dispersion is low, the production efficiency is low, and when the solid content concentration of the spray drying mixture dispersion is too high, the particles obtained by spray drying have concave portions, There are bowl-shaped particles, and the particle density of the particles obtained by firing this at high temperature is likely to fluctuate. When used as a positive electrode material, the strength, density, etc. of the electrode may decrease. Capacity, cycle characteristics, etc. may be insufficient.

[(B) Spraying process]
Subsequently, the spray dispersion mixture dispersion is sprayed into a hot air stream and dried.
The spray drying method is not particularly limited as long as the fine spherical particles of the mixture for spray drying can be obtained, but it is preferable to employ the spray drying method, and the rotating disk method, the pressurized nozzle method, the two-fluid nozzle method. A conventionally known method such as a four-fluid nozzle method can be employed. Here, spray-drying means that fine droplets can be formed and dried to form desired particles, and includes spraying and the like. The inlet temperature of the hot air stream is preferably 180 to 350 ° C, more preferably 190 to 320 ° C. When supplying the spray-drying mixture dispersion to the spray-drying apparatus, the mixture is heated as necessary, but it is desirable to set the pressure constant.

  If the inlet temperature of the hot air stream is too low, drying may be insufficient. If a large amount of moisture remains in the particles, it will cause fine voids in the particles during high-temperature firing, resulting in a spinel-type lithium-manganese composite. In some cases, the particle density of the oxide particles decreases, and the charge / discharge capacity and cycle characteristics become insufficient.

  Even if the inlet temperature of the hot air stream is too high, there are particles with cavities inside or non-spherical particles that do not maintain the particle shape, and spinel-type lithium-manganese composite oxidation obtained by firing this particle In some cases, the density of the product particles decreases, and the charge / discharge capacity and cycle characteristics become insufficient.

  Moreover, it is preferable that the exit temperature of a hot air stream exists in the range of 80-150 degreeC, Furthermore, 90-130 degreeC. The average particle size of the particles obtained by spray drying is generally in the range of 1 to 30 μm.

[(c) Firing step]
Next, the particles obtained by spray drying are fired.
The firing method is not particularly limited as long as spinel type lithium / manganese composite oxide particles having a composition in a predetermined range and excellent crystallinity can be obtained. Conventionally known methods such as a tunnel furnace, a muffle furnace, and a rotary kiln are used. Can be adopted. In the present invention, spinel-type lithium / manganese composite oxide particles having a high density, a lattice constant, a specific surface area within a predetermined range, and a small fluctuation range can be obtained, and further, no fused particles are generated. The firing method is preferred, and the fluctuation range of particle density, lattice constant, and specific surface area is small, and lithium batteries using such spinel-type lithium-manganese composite oxide particles as the cathode material have excellent charge / discharge capacity and cycle characteristics. ing.

The firing temperature is preferably in the range of 650 to 900 ° C, more preferably 700 to 850 ° C.
If the firing temperature is low, the solid phase reaction of spinel crystallization is slow, manganese dioxide may remain, and charge / discharge capacity and cycle characteristics may be insufficient.

  If the firing temperature is too high, lattice defects (particularly oxygen defects) tend to increase, and when used as a positive electrode material, the elution of Mn increases, and the charge / discharge capacity and cycle characteristics may be insufficient. The spinel-type lithium-manganese composite oxide obtained by firing is composed of sufficiently grown crystal particles, and the size of the crystal particles is in the range of about 0.1 to 5.0 μm. The particles are aggregated and sintered to form spherical fine particles having an average particle diameter of 1 to 30 μm.

[(d) Disintegration process]
About the said process (c), it is preferable to perform a crushing process (d).
The particles obtained in the step (c) may have slightly fused particles, and when used in the production of the electrode as they are, the positive electrode current collector is damaged to cause a malfunction or the density of the positive electrode is reduced. There is a case.

The crushing method is not particularly limited as long as spinel-type lithium / manganese composite oxide particles having an average particle diameter (D ₃ ) within a predetermined range can be obtained without impairing crystallinity, and a conventionally known method is adopted. Can do.

After crushing, classification treatment such as sieving may be performed as necessary.
The average particle diameter (D ₃ ) of the spinel-type lithium / manganese composite oxide particles obtained by pulverization is 10 to 20 μm, preferably 13 to 18 μm.

If the average particle size (D ₃ ) of the particles obtained by pulverization is too small, the viscosity of the electrode mixture for preparing the positive electrode film may be increased, and the electrode film forming property may be lowered. The discharge capacity per volume of the type lithium / manganese composite oxide particles may be insufficient. Moreover, the strength (compressive strength) of the electrode film may be insufficient. On the other hand, if the average particle diameter (D ₃ ) is too large, the contact with the conductive agent and the electrolytic solution may be insufficient, and the charge / discharge capacity may be insufficient.

Further, the particle size distribution of the obtained spinel type lithium / manganese composite oxide particles is preferably 2 to 40 μm, more preferably 3 to 25 μm.
When particles having a particle size of less than 2 μm are present in the spinel type lithium / manganese composite oxide particles, the viscosity of the electrode mixture for preparing the positive electrode film may be remarkably increased, and the electrode film formability is lowered. Further, the discharge capacity per volume of the spinel type lithium / manganese composite oxide particles may be insufficient.

  The presence of particles of spinel type lithium / manganese composite oxide particles having a particle diameter exceeding 40 μm may damage the positive electrode current collector, resulting in insufficient contact with the conductive agent and the electrolytic solution, and the charge / discharge capacity is reduced. It may be insufficient.

  To adjust the particle size and particle size distribution, adjust the supply rate of the dispersion, supply pressure, spray drying conditions such as the rotational speed and drying temperature when using a disc, the concentration of the dispersion, the yield stress value, etc. Is possible.

  The spinel-type lithium / manganese composite oxide particles obtained by the above-described method of the present invention are roughly spherical. If such spherical fine particles are used as a positive electrode material, an electrode mixture containing the positive electrode material is applied to an aluminum foil or the like. There is no such thing as damaging the aluminum foil.

  The average particle size and particle size distribution of the spinel type lithium / manganese composite oxide particles were measured using a laser diffraction / scattering type particle size distribution measuring apparatus (Horiba, Ltd .: LA-950v2).

  The lattice constant (Lc) of the obtained spinel-type lithium / manganese composite oxide particles is preferably in the range of 8.15000 to 8.25000 angstroms, preferably 8.16000 to 8.24000 angstroms.

  When the lattice constant (Lc) is small, the charge / discharge capacity may be insufficient. This is considered to be consistent with the fact that the proportion of Li in the spinel-type lithium / manganese composite oxide particles is high and the proportion of Mn is low. When the lattice constant (Lc) is high, the elution amount of Mn increases and the cycle characteristics tend to deteriorate. This is because the ratio of Li in the spinel type lithium / manganese composite oxide particles is low and the ratio of Mn. Is considered to be consistent with the high price. In the present invention, since the dispersion having a specific yield value is used as described above, the fluctuation range of the lattice constant is stabilized, and thereby the fluctuation of the battery performance can be reduced.

  The standard deviation of the lattice constant (Lc) is preferably in the range of 0.00001 to 0.00100 angstrom, more preferably 0.00001 to 0.00095 angstrom.

  It is difficult to obtain a material having a standard deviation of the lattice constant (Lc) of less than 0.00001 angstrom, and if it exceeds 0.00100 angstrom, the discharge capacity and cycle characteristics fluctuate or the performance becomes insufficient. There is a case.

For the lattice constant, a diffraction pattern was measured in the range of 2θ = 15 to 90 ° with a powder X-ray diffractometer (manufactured by Rigaku Corporation: MultiFlex), and the lattice constant was determined by the least square method.
Further, the standard deviation of the lattice constant was calculated by the following formula using the above-mentioned lattice constant.

得られるスピネル型リチウム・マンガン複合酸化物粒子の比表面積が０．１〜２．０ｍ²/ｇ、さらには０．１〜１．５ｍ²/ｇの範囲にあることが好ましい。

The specific surface area of the resulting spinel-type lithium-manganese composite oxide particles 0.1~2.0m ² / g, more preferably in the range of 0.1~1.5m ² / g.

If the specific surface area is less than 0.1 m ² / g, when used as a positive electrode material, contact between the spinel-type lithium-manganese composite oxide particles and conductive agent and the electrolyte is insufficient, the specific surface area of 2.0 m ² / If it exceeds g, the charge / discharge capacity per volume of fine particles is not improved.

The specific surface area was measured by an automatic surface area measuring device (Mounttech's Macsorb HM model-1220).
The filling bulk density (ABD: apparent specific gravity) of the lithium-manganese composite oxide particles obtained in the present invention is 1.0 to 1.6 g / ml, more preferably 1.1 to 1.6 g / ml. ml, and in the range of 1.3 to 1.5 g / ml.

Here, the filling bulk density (ABD) is the volume (V ₁ ) when the lithium-manganese composite oxide particles 25g are dropped by their own weight from the 50 ml graduated cylinder upper opening and filled, and the powder upper part is made horizontal. Was obtained by the following equation.

Filled bulk density (ABD) (g / ml) = 25 / V ₁
If the ABD is too small, the strength of the resulting positive electrode film may be insufficient, and the active material density per unit volume may be insufficient.

  If the ABD is too large, the contact with the conductive material used for the positive electrode formation may be insufficient, and the contact with the electrolyte or the electrolyte may be insufficient, resulting in insufficient charge / discharge capacity. There is a case.

  The compression packing density (CBD: sometimes referred to as true specific gravity) of the lithium-manganese composite oxide particles is 1.5 to 2.1 g / ml, more preferably 1.8 to 2.1 g / ml, and even 1 It is in the range of .9 to 2.1 g / ml.

Here, the compression packing density (CBD) is measured by measuring the volume (V ₂ ) after filling a 50 ml graduated cylinder with 25 g of lithium-manganese composite oxide particles and tapping on a wooden table for 3 minutes. Asked.
Compressed packing density (CBD) (g / ml) = 25 / V ₂

  If the CBD is small, the strength of the obtained positive electrode film may be insufficient, and the active material density per unit volume may be insufficient. Even if the CBD is too large, the contact with the conductive material used for the formation of the positive electrode film may be insufficient, and the contact with the electrolyte or the electrolyte may be insufficient, resulting in insufficient charge / discharge capacity. It may become.

  The CBD / ABD ratio CBD / ABD is preferably in the range of 1.1 to 1.8, more preferably 1.1 to 1.7. When CBD / ABD is less than the above ratio, dispersibility in an organic solvent may be insufficient. When CBD / ABD exceeds the above ratio, when preparing a paste for a positive electrode mixture, a large amount of organic solvent may be required, the viscosity may not be stable, and the positive electrode film formability may be reduced.

The 10% compression modulus of the lithium / manganese composite oxide particles is preferably in the range of ^{20 to} 200 kgf / mm ² , more preferably 40 to 180 kgf / mm ² .
When the 10% compression elastic modulus is less than 20 kgf / mm ² , the lithium-manganese composite oxide particles may be crushed when the positive electrode film is formed, and the film thickness of the positive electrode film may become uneven. . On the other hand, if the 10% compression modulus exceeds 200 kgf / mm ² , the electrode plate may be damaged when forming the positive electrode film.

  The variation in the 10% compression modulus, that is, the coefficient of variation (CV value) is preferably in the range of 5 to 30%, more preferably 5 to 20%. It is difficult to obtain a material with a coefficient of variation (CV value) of 10% compressive modulus exceeding the lower limit of this range, and if it exceeds the upper limit, it is difficult to obtain a particle that is destroyed or damages the electrode plate. There may be places to do. The measurement of the coefficient of variation (CV value) of such 10% compression modulus and 10% compression modulus can be performed by the following method.

10% compressive elastic modulus 10% compressive elastic modulus is fixed to a sample using a micro compression tester (manufactured by Shimadzu Corporation: MCTM-200) as a measuring instrument, and using one particle having a particle diameter of D as a sample. A load is applied at a load speed, the particles are deformed until the compression displacement becomes 10% of the particle diameter, the load and the compression displacement (mm) at the time of 10% displacement are obtained, and the particle diameter and the obtained compression load and displacement are determined. Substituting into the following formula and calculating.
K = (3 / √2) × F × S ^−3/2 × D ^−1/2
here,
K: 10% compression elastic modulus (kgf / mm ² )
F: Compression load (kg)
S: Compression displacement (mm)
D: Particle diameter (mm).
In this specification, 10% compression elastic modulus was measured for each of the 10 particles, and the average value of these particles evaluated the 10% compression elastic modulus of the particles.

Coefficient of variation of 10% compression modulus (CV value)
CV (%) = [10% compression modulus standard deviation (σ) / average 10% compression modulus (K _n )] × 100

つぎに、本発明に係るリチウム・マンガン複合酸化物粒子について説明する。

Next, the lithium-manganese composite oxide particles according to the present invention will be described.

[Lithium / manganese composite oxide particles]
The lithium-manganese composite oxide particles according to the present invention are spinel type lithium-manganese composite oxide particles represented by the following general formula, and the specific surface area is in the range of 0.1 to 2.0 m ² / g. The average particle size (D ₃ ) is in the range of 10-20 μm, the particle size distribution is in the range of 2-40 μm, and the bulk density (ABD) is in the range of 1.0-1.6 g / ml, a range compression packing density (CBD) of 1.5~2.1g / ml, in the range of the ratio CBD / ABD between CBD and ABD is 1.1 to 1.8, the lattice constants are 8.15000～ It is in the range of 8.25000 angstroms, the standard deviation of the lattice constant is in the range of 0.00092 angstroms or less, the 10% compression modulus is in the range of ²⁰ to 200 kgf / mm ² , and the 10% compression modulus is Coefficient of variation (CV value There has been characterized to be in the range of 5-30%.
Li _{(x + y)} Mn _(2-yz) M _z O ₄
(However, x = 1.0 to 1.2, 0 <y ≦ 0.2, 1 <x + y ≦ 1.2, M is Al and B, z1 (Al composition) = 0.01 to 0.2, z2 (B composition) = 0.005 to 0.05, z1 + z2 = Z)

  The lithium-manganese composite oxide particles according to the present invention contain Al and B as elements M other than Li and Mn. The atomic ratio z1 of Al is preferably in the range of 0.01 to 0.2, more preferably 0.02 to 0.18. The atomic ratio z2 of boron is preferably in the range of 0.0005 to 0.05, preferably 0.001 to 0.04.

The amount (x + y) of Li in the spinel type lithium / manganese composite oxide particles is selected from the range of 1.0 to 1.2 in the above general formula.
The average particle size (D ₃ ) of the spinel type lithium / manganese composite oxide particles is preferably in the range of 10 to 20 μm, more preferably 13 to 18 μm.

The particle size distribution of the spinel type lithium / manganese composite oxide particles is preferably in the range of 2 to 40 μm, more preferably 3 to 30 μm.
The spinel-type lithium / manganese composite oxide particles obtained by the method of the present invention are spherical, and if such spherical fine particles are used as a positive electrode material, an electrode mixture containing the positive electrode material is applied to an aluminum foil or the like. There will be no damage to the aluminum foil.

  Next, the lattice constant (Lc) of the spinel type lithium / manganese composite oxide particles is preferably in the range of 8.15000 to 8.25000 angstroms, and preferably in the range of 8.16000 to 8.24000 angstroms.

  The standard deviation of the lattice constant (Lc) is preferably in the range of 0.00001 to 0.00100 angstrom, more preferably 0.00001 to 0.00095 angstrom.

  It is difficult to obtain a material having a standard deviation of the lattice constant (Lc) of less than 0.00001 angstrom, and if it exceeds 0.00100 angstrom, the discharge capacity and cycle characteristics fluctuate or the performance becomes insufficient. There is a case.

Next, the specific surface area of the spinel-type lithium-manganese composite oxide particles 0.1~2.0m ² / g, more preferably in the range of 0.1~1.5m ² / g.
The bulk density (ABD) of the lithium-manganese composite oxide particles is preferably 1.1 to 1.6 g / ml, more preferably 1.3 to 1.5 g / ml.

The compression packing density (CBD) of the lithium-manganese composite oxide particles is preferably in the range of 1.8 to 2.1 g / ml, more preferably 1.9 to 2.1 g / ml.
The CBD / ABD ratio CBD / ABD is preferably 1.1 to 1.8, more preferably 1.1 to 1.5.

The 10% compression modulus of the lithium / manganese composite oxide particles is preferably in the range of ^{20 to} 200 kgf / mm ² , more preferably 40 to 180 kgf / mm ² .
The variation in the 10% compression modulus, that is, the coefficient of variation (CV value) is preferably in the range of 5 to 30%, more preferably 5 to 20%.

The spinel type lithium / manganese composite oxide particles according to the present invention are spinel type lithium / manganese composite oxide particles obtained by the method for producing the spinel type lithium / manganese composite oxide particles according to the present invention. preferable.
Next, the lithium ion secondary battery according to the present invention will be described.

[Lithium ion secondary battery]
The lithium ion secondary battery according to the present invention includes an electrolyte layer, a positive electrode composed of a positive electrode active material layer formed on the positive electrode current collector (1), and a negative electrode current collector (2) laminated in the electrolyte layer. A lithium ion secondary battery comprising a negative electrode comprising a negative electrode active material layer formed on the electrode and a separator separating the positive electrode from the negative electrode, wherein the positive electrode comprises a spinel-type lithium / manganese composite oxide according to the present invention. The particles are used as a positive electrode material (positive electrode active material).

  A conventionally well-known thing can be especially used for a negative electrode active material used with the lithium secondary battery of this invention without a restriction | limiting. For example, metallic lithium and a substance capable of occluding and releasing lithium or lithium ions can be used. Examples include lithium metal, lithium / aluminum alloy, lithium / tin alloy, lithium / lead alloy, and carbon-based materials that electrochemically insert and desorb lithium ions, and electrochemically insert and desorb lithium ions. The carbon-based material to be used is particularly suitable from the viewpoints of safety and battery characteristics. The electrolyte used in the lithium secondary battery of the present invention is not particularly limited. For example, an electrolyte obtained by dissolving a lithium salt in an organic solvent such as carbonates, sulfolanes, lactones, and ethers, or lithium ions A conductive solid electrolyte can be used.

In the present invention, a stable high-performance lithium secondary battery can be obtained using the above positive electrode material (positive electrode active material), negative electrode active material, and lithium salt-containing nonaqueous electrolyte.
EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to the following Example.

[Example]
EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples.

[Example 1]
Preparation of spinel type lithium / manganese composite oxide particles (1) Electrolytic manganese dioxide powder (γ-MnO ₂ , purity 60.64%), alumina sol (manufactured by JGC Catalysts & Chemicals Co., Ltd .: AS-3, average primary particle size 8 nm) , Average secondary particle size 250 nm, Al ₂ O ₃ concentration 7.1 wt%), lithium hydroxide (manufactured by Nippon Chemical Industry Co., Ltd .: LiOH, purity 58.6 wt%), boric acid (Wako Pure Chemical Industries, Ltd.) ): H ₃ BO ₃ , purity 99.0% by weight) at a ratio of Li: Mn: Al: B = 1.07: 1.82: 0.1: 0.01 (atomic ratio) And charged with pure water to a slurry solids concentration of 33% by weight, treated with 1.0 mmΦ beads at a rotational speed of 2500 rpm for 1 hour, and pure water was added to the solid content. A spray-drying mixture dispersion (1) having a concentration of 20% by weight was prepared. The pH of the mixture dispersion (1) for spray drying was 12.7. The yield stress value was 22 Pa.

The average primary particle diameter (D ₁ ) of the manganese dioxide particles (A) was measured with a particle size distribution analyzer (manufactured by HORIBA Ltd .: LA-950v2), and the results are shown in the table. Further, the zeta potential of the manganese dioxide particles (A) in the mixture dispersion (1) for spray drying was measured, and the results are shown in the table.

Subsequently, the spray dispersion mixture dispersion (1) was spray-dried with a spray dryer. The conditions of the spray dryer were a hot air inlet temperature of 200 ° C. and an outlet temperature of 100 ° C.
The obtained dry powder is fired at 830 ° C. for 6 hours under air flow to have a composition of Li: Mn: Al: B = 1.07: 1.82: 0.1: 0.01 (atomic ratio). Spinel-type lithium-manganese composite oxide particles were obtained.

Next, it is charged in a mixer for cooking and pulverized for 30 seconds. Then, classification is performed for 1 minute using a magnetic sieve shaker under conditions of a sieve opening of 45 μm and an amplitude of 3.0 mm. Spinel-type lithium-manganese composite oxide particles (1) were prepared.
The average particle size (D ₃ ), particle size distribution, specific surface area, ABD, CBD, lattice constant and 10% compression modulus of the spinel type lithium / manganese composite oxide particles (1) were measured, and the results are shown in the table.

Performance Evaluation A lithium ion battery (1) was prepared using a positive electrode containing spinel type lithium / manganese composite oxide particles (1) as a positive electrode active material, and the battery performance was evaluated.

  First, spinel-type lithium / manganese composite oxide particles (1), acetylene black as a conductive material, and polytetrafluoroethylene powder as a binder are mixed at a weight ratio of 75: 20: 5 and kneaded in a mortar. A positive electrode mixture was prepared. This mixture was made into a sheet having a thickness of 0.1 mm with a spreading roller, die-cut to 16 mmφ, and dried in a glove box to prepare a test positive electrode (1).

A positive electrode (1) and a metal lithium foil (thickness: 0.2 mm) are stacked on a coin-type battery case via a separator (trade name: Celgard), and 1 mol of ethylene carbonate and dimethyl carbonate mixed solvent with a volume ratio of 1: 1. A test battery (1) was prepared by injecting an electrolytic solution in which 1 / L LiPF ₆ was dissolved.
The test battery (1) was subjected to discharge capacity, high temperature cycle characteristics, and high temperature deterioration test.

(1) Discharge capacity First, after measuring the discharge capacity per weight under the conditions of a constant current of 0.5 mA / cm ² , a charge potential of 4.3 V, and a potential regulation of 3.0 V, the next The discharge capacity per volume was calculated from the equation.
Discharge capacity per volume = discharge capacity per weight × packing density (2) High-temperature cycle characteristics The test battery is placed in a constant temperature bath at 60 ° C., and 30 charge / discharge tests are performed under the same conditions as described above. The characteristics were evaluated by the capacity retention rate of the following equation.
Capacity retention rate (%) = (discharge capacity per first weight / discharge capacity per 30th weight) × 100

[Example 2]
Preparation of Spinel Type Lithium Manganese Composite Oxide Particles (2) A slurry with a solid content concentration of 33% by weight was prepared in the same manner as in Example 1 and 0.5 mmΦ beads were used for 1 hour under the conditions of 2500 rpm. After the treatment, pure water was added thereto to prepare a spray-drying mixture dispersion (2) having a solid content of 20% by weight. The pH of the mixture dispersion (2) for spray drying was 12.6 ". The yield stress value was 320 Pa.

Further, the average primary particle diameter (D ₁ ) of the manganese dioxide particles (A) and the zeta potential of the manganese dioxide particles (A) were measured, and the results are shown in the table.
Subsequently, the mixture dispersion (2) for spray drying was spray dried with a spray dryer, calcined, crushed and classified in the same manner as in Example 1, and Li: Mn: Al: B = 1.07: 1. Spinel type lithium / manganese composite oxide particles (2) having a composition of 82: 0.1: 0.01 (atomic ratio) were prepared.
The average particle size (D ₃ ), particle size distribution, specific surface area, ABD, CBD, lattice constant and 10% compression modulus of the spinel type lithium / manganese composite oxide particles (2) were measured, and the results are shown in the table.

  In addition, a test battery (2) using spinel type lithium / manganese composite oxide particles (2) was prepared, performance evaluation was performed, and the results are shown in the table.

[Example 3]
Preparation of Spinel Type Lithium Manganese Composite Oxide Particles (3) A slurry having a solid content concentration of 33% by weight was prepared in the same manner as in Example 1 and 3.0 mmΦ beads were used for 1 hour at a rotation speed of 2500 rpm. After the treatment, pure water was added thereto to prepare a spray-drying mixture dispersion (3) having a solid concentration of 20% by weight. The pH of the mixture dispersion (3) for spray drying was 12.8. Moreover, the yield stress value was 13 Pa.

Further, the average primary particle diameter (D ₁ ) of the manganese dioxide particles (A) and the zeta potential of the manganese dioxide particles (A) were measured, and the results are shown in the table.
Subsequently, the mixture dispersion (3) for spray drying was spray dried with a spray dryer, calcined, crushed, classified in the same manner as in Example 1, and Li: Mn: Al: B = 1.07: 1. Spinel type lithium / manganese composite oxide particles (3) having a composition of 82: 0.1: 0.01 (atomic ratio) were prepared.
The average particle size (D ₃ ), particle size distribution, specific surface area, ABD, CBD, lattice constant and 10% compression modulus of the spinel type lithium / manganese composite oxide particles (3) were measured, and the results are shown in the table.

  In addition, a test battery (3) using spinel type lithium / manganese composite oxide particles (3) was prepared, performance evaluation was performed, and the results are shown in the table.

[Example 4]
Preparation of spinel type lithium / manganese composite oxide particles (4) Electrolytic manganese dioxide powder (γ-MnO ₂ , purity 60.64%), alumina sol (manufactured by JGC Catalysts & Chemicals Co., Ltd .: AS-3, average primary particle size 8 nm) , Average secondary particle size 250 nm, Al ₂ O ₃ concentration 7.1 wt%), lithium hydroxide (manufactured by Nippon Chemical Industry Co., Ltd .: LiOH, purity 58.6 wt%), boric acid (Wako Pure Chemical Industries, Ltd.) ): H ₃ BO ₃ , purity 99.0% by weight) at a ratio of Li: Mn: Al: B = 1.07: 1.77: 0.15: 0.01 (atomic ratio) And charged with pure water to a slurry solids concentration of 33% by weight, treated with 1.0 mmΦ beads at a rotational speed of 2500 rpm for 1 hour, and pure water was added to the solid content. A spray dispersion mixture dispersion (4) having a concentration of 20% by weight was prepared. The pH of the mixture dispersion (4) for spray drying was 12.5. The yield stress value was 52 Pa.

Further, the average primary particle diameter (D ₁ ) of the manganese dioxide particles (A) and the zeta potential of the manganese dioxide particles (A) were measured, and the results are shown in the table.
Subsequently, the mixture dispersion (4) for spray drying was spray dried with a spray dryer, calcined, crushed, classified in the same manner as in Example 1, and Li: Mn: Al: B = 1.07: 1. Spinel type lithium / manganese composite oxide particles (4) having a composition of 77: 0.15: 0.01 (atomic ratio) were prepared.
The average particle size (D ₃ ), particle size distribution, specific surface area, ABD, CBD, lattice constant and 10% compression modulus of the spinel type lithium / manganese composite oxide particles (4) were measured, and the results are shown in the table.

  In addition, a test battery (4) using spinel type lithium / manganese composite oxide particles (4) was prepared, performance evaluation was performed, and the results are shown in the table.

[Example 5]
Preparation of spinel type lithium / manganese composite oxide particles (5) Electrolytic manganese dioxide powder (γ-MnO ₂ , purity 60.64%), alumina sol (manufactured by JGC Catalysts & Chemicals Co., Ltd .: AS-3, average primary particle size 8 nm) , Average secondary particle size 250 nm, Al ₂ O ₃ concentration 7.1 wt%), lithium hydroxide (manufactured by Nippon Chemical Industry Co., Ltd .: LiOH, purity 58.6 wt%), boric acid (Wako Pure Chemical Industries, Ltd.) ): H ₃ BO ₃ , purity 99.0% by weight) at a ratio of Li: Mn: Al: B = 1.07: 1.74: 0.18: 0.01 (atomic ratio) And charged with pure water to a slurry solids concentration of 33% by weight, treated with 1.0 mmΦ beads at a rotational speed of 2500 rpm for 1 hour, and pure water was added to the solid content. A mixture dispersion (5) for spray drying having a concentration of 20% by weight was prepared. The pH of the mixture dispersion (5) for spray drying was 12.3. The yield stress value was 104 Pa.

Further, the average primary particle diameter (D ₁ ) of the manganese dioxide particles (A) and the zeta potential of the manganese dioxide particles (A) were measured, and the results are shown in the table.
Subsequently, the mixture dispersion (5) for spray drying was spray dried with a spray dryer, calcined, crushed, classified in the same manner as in Example 1, and Li: Mn: Al: B = 1.07: 1. Spinel type lithium-manganese composite oxide particles (5) having a composition of 74: 0.18: 0.01 (atomic ratio) were prepared.
The average particle size (D ₃ ), particle size distribution, specific surface area, ABD, CBD, lattice constant and 10% compression modulus of the spinel type lithium / manganese composite oxide particles (5) were measured, and the results are shown in the table.

In addition, a test battery (5) using spinel type lithium / manganese composite oxide particles (5) was prepared, performance evaluation was performed, and the results are shown in the table.

[Comparative Example 1]
Preparation of Spinel Type Lithium Manganese Composite Oxide Particles (R1) A slurry with a solid content concentration of 33% by weight was prepared in the same manner as in Example 1, and 0.1 mmΦ beads were used for 1 hour under the condition of 2500 rpm. After the treatment, pure water was added thereto to prepare a spray-drying mixture dispersion (R1) having a solid content of 20% by weight. The pH of the mixture dispersion (R1) for spray drying was 12.5. The yield stress value was 570 Pa.

Further, the average primary particle diameter (D ₁ ) of the manganese dioxide particles (A) and the zeta potential of the manganese dioxide particles (A) were measured, and the results are shown in the table.
Subsequently, the mixture dispersion (R1) for spray drying was spray dried with a spray dryer, calcined, crushed, classified in the same manner as in Example 1, and Li: Mn: Al: B = 1.07: 1. Spinel type lithium / manganese composite oxide particles (R1) having a composition of 82: 0.1: 0.01 (atomic ratio) were prepared.
The average particle size (D ₃ ), particle size distribution, specific surface area, ABD, CBD, lattice constant and 10% compression modulus of the spinel type lithium / manganese composite oxide particles (R1) were measured, and the results are shown in the table.

  In addition, a test battery (R1) using spinel type lithium / manganese composite oxide particles (R1) was prepared, performance evaluation was performed, and the results are shown in the table.

[Comparative Example 2]
Preparation of Spinel Type Lithium / Manganese Composite Oxide Particles (R2) A slurry having a solid content concentration of 33% by weight was prepared in the same manner as in Example 1 and 5.0 mmΦ beads were used for 1 hour under the conditions of 2500 rpm. This was treated, and pure water was added thereto to prepare a spray-drying mixture dispersion (R2) having a solid concentration of 20% by weight. The pH of the mixture dispersion (R2) for spray drying was 12.8. The yield stress value was 4 Pa.

Further, the average primary particle diameter (D ₁ ) of the manganese dioxide particles (A) and the zeta potential of the manganese dioxide particles (A) were measured, and the results are shown in the table.
Subsequently, the mixture dispersion (R2) for spray-drying was spray-dried with a spray dryer, calcined, crushed, classified in the same manner as in Example 1, and Li: Mn: Al: B = 1.07: 1. Spinel type lithium / manganese composite oxide particles (R2) having a composition of 82: 0.1: 0.01 (atomic ratio) were prepared.
The average particle size (D ₃ ), particle size distribution, specific surface area, ABD, CBD, lattice constant and 10% compression modulus of the spinel type lithium / manganese composite oxide particles (R2) were measured, and the results are shown in the table.

  Also, a test battery (R2) using spinel type lithium / manganese composite oxide particles (R2) was prepared, performance evaluation was performed, and the results are shown in the table.

[Comparative Example 3]
Preparation of spinel type lithium / manganese composite oxide particles (R3) Electrolytic manganese dioxide powder (γ-MnO ₂ , purity 60.64%), alumina sol (manufactured by JGC Catalysts & Chemicals Co., Ltd .: AS-3, average primary particle size 8 nm) , Average secondary particle size 250 nm, Al ₂ O ₃ concentration 7.1 wt%), lithium hydroxide (manufactured by Nippon Chemical Industry Co., Ltd .: LiOH, purity 58.6 wt%), boric acid (Wako Pure Chemical Industries, Ltd.) ): H ₃ BO ₃ , purity 99.0% by weight) at a ratio of Li: Mn: Al: B = 1.07: 1.912: 0.008: 0.01 (atomic ratio) And charged with pure water to a slurry solids concentration of 33% by weight, treated with 1.0 mmΦ beads at a rotational speed of 2500 rpm for 1 hour, and pure water was added to the solid content. Prepare a spray dispersion mixture dispersion (R3) with a concentration of 20% by weight. . The pH of the mixture dispersion (R3) for spray drying was 12.9. The yield stress value was 3 Pa.

Further, the average primary particle diameter (D ₁ ) of the manganese dioxide particles (A) and the zeta potential of the manganese dioxide particles (A) were measured, and the results are shown in the table.
Subsequently, the mixture dispersion (R3) for spray drying was spray dried with a spray dryer, calcined, crushed and classified in the same manner as in Example 1, and Li: Mn: Al: B = 1.07: 1. Spinel-type lithium / manganese composite oxide particles (R3) having a composition of 912: 0.008: 0.01 (atomic ratio) were prepared.
The average particle size (D ₃ ), particle size distribution, specific surface area, ABD, CBD, lattice constant and 10% compression modulus of the spinel type lithium / manganese composite oxide particles (R3) were measured, and the results are shown in the table.

  Further, a test battery (R3) using spinel type lithium / manganese composite oxide particles (R3) was prepared, performance evaluation was performed, and the results are shown in the table.

[Comparative Example 4]
Preparation of spinel type lithium / manganese composite oxide particles (R4) Electrolytic manganese dioxide powder (γ-MnO ₂ , purity 60.64%), alumina sol (manufactured by JGC Catalysts & Chemicals Co., Ltd .: AS-3, average primary particle size 8 nm) , Average secondary particle size 250 nm, Al ₂ O ₃ concentration 7.1 wt%), lithium hydroxide (manufactured by Nippon Chemical Industry Co., Ltd .: LiOH, purity 58.6 wt%), boric acid (Wako Pure Chemical Industries, Ltd.) ): H ₃ BO ₃ , purity 99.0% by weight) at a ratio of Li: Mn: Al: B = 1.07: 1.42: 0.5: 0.01 (atomic ratio) And charged with pure water to a slurry solids concentration of 33% by weight, treated with 1.0 mmΦ beads at a rotational speed of 2500 rpm for 1 hour, and pure water was added to the solid content. A spray-drying mixture dispersion (R4) having a concentration of 20% by weight was prepared. The pH of the spray-drying mixture dispersion (R4) was 12.5. The yield stress value was 620 Pa.

Further, the average primary particle diameter (D ₁ ) of the manganese dioxide particles (A) and the zeta potential of the manganese dioxide particles (A) were measured, and the results are shown in the table.
Subsequently, the mixture dispersion (R4) for spray drying was spray dried with a spray dryer, calcined, crushed, classified in the same manner as in Example 1, and Li: Mn: Al: B = 1.07: 1. Spinel type lithium / manganese composite oxide particles (R4) having a composition of 42: 0.5: 0.01 (atomic ratio) were prepared.
The average particle size (D ₃ ), particle size distribution, specific surface area, ABD, CBD, lattice constant and 10% compression modulus of the spinel type lithium / manganese composite oxide particles (R4) were measured, and the results are shown in the table.

  In addition, a test battery (R4) using spinel type lithium / manganese composite oxide particles (R4) was prepared, performance evaluation was performed, and the results are shown in the table.

[Comparative Example 5]
Preparation of Spinel Type Lithium-Manganese Composite Oxide Particles (R5) Electrolytic manganese dioxide powder (γ-MnO ₂ , purity 60.64%), alumina powder obtained by spray drying alumina sol used in Example 1 (JGC Catalyst) Kasei Co., Ltd .: AP-3, average primary particle diameter 8 nm, average secondary particle diameter 5500 nm, Al ₂ O ₃ concentration 99.0 wt%, lithium hydroxide (Nippon Chemical Industry Co., Ltd .: LiOH, purity 58.6% by weight), boric acid (Wako Pure Chemical Industries, Ltd .: H ₃ BO ₃ , purity 99.0% by weight), Li: Mn: Al: B = 1.07: 1.82: 0. Filled into a wet pulverizer at a ratio of 1: 0.01 (atomic ratio), charged with pure water to a slurry solids concentration of 33% by weight, using 1.0 mmΦ beads, and rotating at 2500 rpm For 1 hour, and then add pure water to add solid content 0 wt% of the spray-drying mixture dispersion (R5) was prepared. The pH of the mixture dispersion (R5) for spray drying was 12,8. The yield stress value was 4 Pa.

Further, the average primary particle diameter (D ₁ ) of the manganese dioxide particles (A) and the zeta potential of the manganese dioxide particles (A) were measured, and the results are shown in the table.
Subsequently, the mixture dispersion (R5) for spray drying was spray dried with a spray dryer, calcined, crushed and classified in the same manner as in Example 1, and Li: Mn: Al: B = 1.07: 1. Spinel type lithium-manganese composite oxide particles (R5) having a composition of 82: 0.1: 0.01 (atomic ratio) were prepared.
The average particle size (D ₃ ), particle size distribution, specific surface area, ABD, CBD, lattice constant and 10% compression modulus of the spinel type lithium / manganese composite oxide particles (R5) were measured, and the results are shown in the table.

  In addition, a test battery (R5) using spinel type lithium / manganese composite oxide particles (R5) was prepared, performance evaluation was performed, and the results are shown in the table.

Claims (8)

A process for producing spinel-type lithium-manganese composite oxide particles comprising the following steps (a) to (c);
(A) Lithium compound, manganese dioxide particles (A) having an average primary particle diameter (D ₁ ) in the range of 0.1 μm ≦ (D ₁ ) ≦ 1 μm, alumina sol, and boron compound, Li: Mn: Al: B The atomic ratio of (x + y) :( 2-yz): z1: z2 (where 1.0 ≦ x ≦ 1.2, 0 <y ≦ 0.2, 1 <x + y ≦ 1.2, 0. 01 ≦ z1 (Al) ≦ 0.2, 0.0005 ≦ z2 (B) ≦ 0.05, z = z1 + z2), and the solid content concentration is in the range of 5 ≦ solid content concentration ≦ 50% by weight. to Yes, the yield stress value of the partial dispersion liquid is in the range of 5 Pa ≦ yield stress value ≦ 500 Pa,
preparing a spray-drying mixture dispersion having a pH in a range of 9 ≦ pH ≦ 14 .
(B) A step of spray drying.
(C) A step of firing. The method for producing spinel-type lithium / manganese composite oxide particles according to claim 1, wherein the following step (d) is further performed following the step (c).
(D) A step of crushing so that the average particle size (D ₃ ) is in the range of 10 μm ≦ (D ₃ ) ≦ 20 μm, and the particle size distribution is 2 μm ≦ particle size distribution ≦ 40 μm. The spinel-type lithium-manganese composite oxide according to claim 1 or 2, wherein the zeta potential of the manganese dioxide particles (A) in the step (a) is in the range of -60 mV ≤ zeta potential ≤ -5 mV . Particle production method. The filling bulk density (ABD) is in the range of 1.0 g / ml ≦ (ABD) ≦ 1.6 g / ml, and the compression packing density (CBD) is 1.5 g / ml ≦ (CBD) ≦ 2.1 g / The spinel-type lithium-ion according to any one of claims 1 to 3, wherein a ratio CBD / ABD of CBD to ABD is in a range of 1.1 ≦ CBD / ABD ≦ 1.8 in a range of ml. A method for producing manganese composite oxide particles. 10% compressive elasticity modulus is in the range of 20 kgf / mm ² ≦ 10% compressive elasticity modulus ≦ 200kgf / mm ^2, coefficient of variation of 10% compressive elasticity modulus (CV value) is 5% ≦ (CV value) ≦ 30% The method for producing spinel-type lithium-manganese composite oxide particles according to any one of claims 1 to 4, wherein: Spinel-type lithium / manganese composite oxide particles represented by the following general formula:
The specific surface area is in the range of 0.1 m ² / g ≦ specific surface area ≦ 2.0 m ² / g,
The average particle diameter (D ₃ ) is in the range of 10 μm ≦ (D ₃ ) ≦ 20 μm,
The particle size distribution is in the range of 2 μm ≦ particle size distribution ≦ 40 μm,
The filling bulk density (ABD) is in the range of 1.0 g / ml ≦ (ABD) ≦ 1.6 g / ml,
The compression packing density (CBD) is in the range of 1.5 g / ml ≦ (CBD) ≦ 2.1 g / ml,
The ratio CBD / ABD between CBD and ABD is in the range 1.1 ≦ CBD / ABD ≦ 1.8,
The lattice constant is in the range of 8.15000 ≦ lattice constant ≦ 8.25000 angstroms;
The standard deviation of the lattice constant is 0.00092 angstrom or less,
10% compressive elasticity modulus is in the range of 20 kgf / mm ² ≦ 10% compressive elasticity modulus ≦ 200kgf / mm ^2,
Lithium-manganese composite oxide particles, wherein the coefficient of variation (CV value) of 10% compression modulus is in the range of 5 % ≦ (CV value) ≦ 30%.
Li _{(x + y)} Mn _(2-yz) M _z O ₄
(However, 1.0 ≦ x ≦ 1.2, 0 <y ≦ 0.2, 1 <x + y ≦ 1.2, M is Al and B, 0.01 ≦ z1 (Al) ≦ 0.2, 0 .0005 ≦ z2 (B) ≦ 0.05, z = z1 + z2 )   The lithium-manganese composite oxide particles according to claim 6, wherein the lithium-manganese composite oxide particles are produced by the method for producing spinel-type lithium / manganese composite oxide particles according to claim 1.   6. A lithium ion secondary battery using spinel-type lithium / manganese composite oxide particles produced by the production method according to claim 1 as a positive electrode material.