JP2002321920A - Element substitution lithium manganese compound oxide granulated composition, its manufacturing method and its utilization for secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lithium manganese compound oxide granulated composition and its manufacturing method which has a high energy density and a high charge and discharge capacity, and excels in cycle characteristics when used for a positive electrode active material of a lithium ion secondary battery. SOLUTION: The lithium manganese compound oxide granulated composition is characterized in that general formula (1) is a compound oxide represented by Lix Mn1-a-b Cra Mb Oy (1) (wherein, M is B, Mg, Al, Si, Sc, Ti, V, Fe, Co, Ni, Cu, Zn, Ga, Y, Zr, Nb, Mo, Ru, Sn, Sb, Hf, Ta, Pb and at least one kind of elements selected from the group consisting of a rare earth element), a crystal system comprises a compound oxide in which the crystal system is monoclinic crystal or a mixture of the compound oxide in which the crystal system is monoclinic crystal and orthohombic crystal and an intensity ratio R defined by I (orthohombic crystal)/I (monoclinic crystal) in X-ray diffraction is within the range of 0 to 0.3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lithium manganese composite oxide particulate composition useful as a positive electrode active material of a lithium ion secondary battery and a method for producing the same, and further relates to this lithium manganese composite oxide particulate composition. The present invention relates to a lithium ion secondary battery using as a positive electrode active material.

[0002]

2. Description of the Related Art As a positive electrode active material of a lithium ion secondary battery, a lithium cobalt composite oxide (LiCoO ₂ ) having a theoretical capacity of 274 mAh / g has been conventionally used. However, since lithium cobalt composite oxide uses cobalt as a raw material, its production cost is high, and its resources are limited.
Thus, as a lithium manganese composite oxide using manganese as a raw material, which is abundant in resources, 4V-class LiMn ₂ O ₄ having a spinel structure has been proposed as a positive electrode active material. However, this composite oxide has a drawback that the theoretical capacity is as low as 148 mAh / g and the charge / discharge cycle performance is inferior.

Under these circumstances, tetragonal Li ₂ Mn ₂ O ₄ and orthorhombic or monoclinic LiMnO ₄ having the same theoretical capacity (285 mAh / g) as lithium cobaltate are used.
₂ has attracted attention as an alternative material to lithium cobalt oxide, and is expected as a positive electrode material for lithium ion secondary batteries.

LiMnO ₂ having a monoclinic structure has already been described in JP-A-11-21128. Also,
A composite oxide in which part of the manganese atom of LiMnO ₂ having a monoclinic structure is substituted with a substitution element is disclosed in, for example,
No. 00-294242. Further, a composite oxide in which a lithium atom of LiMnO ₂ having a monoclinic structure is partially substituted with a substitution element is disclosed in, for example,
No. 317225. Further, composite oxides in which lithium atoms and a part of manganese atoms are each substituted by a substitution element are also disclosed in, for example, JP-A-11-317226.
And JP-A-2000-133266.

In a lithium ion secondary battery using such a lithium manganese composite oxide as a positive electrode active material, capacity and cycle characteristics are higher than those of a conventional manganese-based positive electrode active material containing spinel type LiMn ₂ O _4. However, there is a strong demand for further improvement in characteristics and cost reduction.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in a lithium manganese composite oxide as a positive electrode active material of a lithium ion secondary battery. It is intended to provide a lithium manganese composite oxide particulate composition having a high energy density, a high charge / discharge capacity, and excellent cycle characteristics when used as a positive electrode active material, and a method for producing the same. I do.

Another object of the present invention is to provide a high-performance and inexpensive lithium ion secondary battery using such a lithium manganese composite oxide particulate composition as a positive electrode active material.

[0008]

According to the present invention, there is provided a compound represented by the general formula (I): Li _x Mn _1-ab C _a M _b O _y (where M is B, Mg, Al, Si, Sc, Ti, V,
Fe, Co, Ni, Cu, Zn, Ga, Y, Zr, N
b, Mo, Ru, Sn, Sb, Hf, Ta, Pb and at least one element selected from the group consisting of rare earth elements, wherein x, y, a and b are respectively 0.8 ≦ x ≦ 1. 2, 1.8 ≦ y ≦ 2.4, 0 <a ≦ 0.2, and 0 ≦ b ≦ 0.2. A) a composite oxide represented by
A composite oxide having a monoclinic crystal system or a mixture of a composite oxide having a monoclinic crystal system and a composite oxide having an orthorhombic crystal system. (Orthorhombic)
/ I (monoclinic), wherein the lithium-manganese composite oxide particulate composition is characterized in that the intensity ratio R is in the range of 0 to 0.3. Hereinafter, this is referred to as a first lithium manganese composite oxide particulate composition according to the present invention.

Further, according to the present invention, the general formula (II) (where M is B, Mg, Al, Si, Sc, Ti, V, F
e, Co, Ni, Cu, Zn, Ga, Y, Zr, Nb,
Mo represents at least one element selected from the group consisting of Mo, Ru, Sn, Sb, Hf, Ta, Pb and a rare earth element; N represents at least one element selected from the group consisting of In and W; , Y, a, b and c are
It is a number that satisfies 0.8 ≦ x ≦ 1.2, 1.8 ≦ y ≦ 2.7, 0 <a ≦ 0.2, 0 ≦ b ≦ 0.2, and 0 <c ≦ 0.2. A) a composite oxide represented by
A composite oxide having a monoclinic crystal system or a mixture of a composite oxide having a monoclinic crystal system and a composite oxide having an orthorhombic crystal system. (Orthorhombic)
/ I (monoclinic), wherein the lithium-manganese composite oxide particulate composition is characterized in that the intensity ratio R is in the range of 0 to 0.3. Hereinafter, this is referred to as a second lithium manganese composite oxide particulate composition according to the present invention.

Further, according to the present invention, a compound of a lithium compound, a trivalent manganese compound, a chromium compound and an element M (a compound of two or more elements among compounds of three elements of manganese, chromium and element M) May be a solid solution compound), and a second step of firing the mixture in an inert gas atmosphere to obtain a mixture. A method for producing a composite oxide particulate composition is provided.

Further, a lithium compound, a trivalent manganese compound, a chromium compound, a compound of the element M, and a compound of the element N (two or more of the compounds of the four elements of manganese, chromium, the element M, and the element N) A compound may be a solid solution compound) to obtain a mixture;
A second step of firing the mixture in an inert gas atmosphere. The method for producing the second lithium manganese composite oxide particulate composition, comprising:

In addition to the above, according to the present invention, there is further provided a lithium ion secondary battery comprising a positive electrode, a negative electrode and an electrolyte, wherein the lithium manganese composite oxide particulate composition described above is used as a positive electrode active material. An ion secondary battery is provided.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The first lithium manganese composite oxide particulate composition according to the present invention has the general formula (I) Li _x Mn _{1 -ab} C _a M _b O _y (where M is B, Mg , Al, Si, Sc, Ti, V,
Fe, Co, Ni, Cu, Zn, Ga, Y, Zr, N
b, Mo, Ru, Sn, Sb, Hf, Ta, Pb and at least one element selected from the group consisting of rare earth elements, wherein x, y, a and b are respectively 0.8 ≦ x ≦ 1. 2, 1.8 ≦ y ≦ 2.4, 0 <a ≦ 0.2, and 0 ≦ b ≦ 0.2. A) a composite oxide represented by
A composite oxide having a monoclinic crystal system or a mixture of a composite oxide having a monoclinic crystal system and a composite oxide having an orthorhombic crystal system. (Orthorhombic)
/ I (monoclinic) is in the range of 0 to 0.3.

That is, the first lithium manganese composite oxide particulate composition according to the present invention is obtained by substituting a part of manganese atoms of the lithium manganese composite oxide with chromium (and the element M).

The second lithium manganese composite oxide particulate composition according to the present invention has a general formula (II) Li _x Mn _{1 -ab C a} M _b N _c O _y (where M is B, Mg, Al , Si, Sc, Ti, V,
Fe, Co, Ni, Cu, Zn, Ga, Y, Zr, N
b, Mo, Ru, Sn, Sb, Hf, Ta, Pb and at least one element selected from the group consisting of rare earth elements; N represents at least one element selected from the group consisting of In and W; , X, y, a, b and c are respectively 0.8 ≦ x ≦ 1.2, 1.8 ≦ y ≦ 2.7, 0 <a ≦ 0.2, 0 ≦ b ≦ 0.2, 0 <C ≦ 0.2. A) a composite oxide represented by
A composite oxide having a monoclinic crystal system or a mixture of a composite oxide having a monoclinic crystal system and a composite oxide having an orthorhombic crystal system. (Orthorhombic)
/ I (monoclinic) is in the range of 0 to 0.3.

That is, the second lithium manganese composite oxide particulate composition according to the present invention is obtained by further substituting a part of the manganese atoms of the first lithium manganese composite oxide particulate composition with the element N. Things.

According to the present invention, the first and second lithium
When the manganese composite oxide particulate composition is “monoclinic in the crystal system,
Composites consisting of composite oxides or monoclinic crystals
From a mixture of oxide and complex oxide whose crystal system is orthorhombic
`` Naru '' means that the lithium manganese composite oxide particles
The X-ray diffraction chart of the product
CPDS (Joint Committee Powder Diffraction Stand
ard) Although not listed on the card, for example,
No. 1-21128 and M. Tabuchi et al., J. Electr
ochem. Soc., Vol. 145, L49)
LiMnO_TwoWith the same peak pattern as
Consisting of a particulate manganese composite oxide
L, which is a lithium manganese composite oxide having an orthorhombic structure
iMnO _TwoConsisting of a mixture of

Further, according to the present invention, the first and second lithium manganese composite oxide particulate compositions are defined by "I (orthorhombic) / I (monoclinic) in X-ray diffraction". "The intensity ratio R is in the range of 0 to 0.3." (01
The ratio R (that is, R = I (orthorhombic) / I (monoclinic)) of the diffraction intensity (hereinafter, referred to as I (orthorhombic)) of the diffraction peak of the 0) plane is 0 to 0.3. Means in range.

As described above, the strength ratio R is defined as I (orthogonal) / I (monoclinic), and the lithium manganese composite oxide particulate composition according to the present invention also has the first composition. ,
The second one also has the intensity ratio R in the range of 0 to 0.3. The greater the strength ratio R, the higher the ratio of orthorhombic in a mixture of a composite oxide having a monoclinic crystal system and a composite oxide having a crystal system orthorhombic. A lithium ion secondary battery used as an active material tends to have poor cycle characteristics and charge / discharge capacity. When the strength ratio R exceeds 0.3, the obtained lithium ion secondary battery does not have practically sufficient cycle characteristics. According to the invention, the intensity ratio R preferably ranges from 0 to 0.2.

In the present invention, the first lithium manganese composite oxide particulate composition represented by the general formula (I) and the second lithium manganese composite oxide particulate composition represented by the general formula (II) In the composition, chromium, the element M, and the element N are elements that substitute a part of manganese atoms (hereinafter, referred to as substitution elements).

That is, chromium is the first and the second according to the present invention.
In the lithium manganese composite oxide particulate composition of,
A first substitution element for substituting a part of a manganese atom,
The element M is a second substitution element that substitutes a part of manganese atoms in the first and second lithium manganese composite oxide particulate compositions according to the present invention, and includes B, Mg, Al,
Si, Sc, Ti, V, Fe, Co, Ni, Cu, Z
n, Ga, Y, Zr, Nb, Mo, Ru, Sn, Sb,
It is at least one selected from the group consisting of Hf, Ta, Pb and rare earth elements. In the present invention, the rare earth element is preferably Ce, Pr, Nd and / or Eu.
It is.

The third substituting element N is a third substituting element for substituting a part of manganese atoms in the second lithium manganese composite oxide particulate composition according to the present invention,
At least one selected from the group consisting of In and W.

According to the present invention, in the first lithium-manganese composite oxide particulate composition, the ratio x of lithium atoms, the ratio y of oxygen atoms, and the first and second substitution elements are manganese atoms. The replacement ratios a and b are in the ranges satisfying 0.8 ≦ x ≦ 1.2, 1.8 ≦ y ≦ 2.4, 0 <a ≦ 0.2, and 0 ≦ b ≦ 0.2, respectively.

Further, according to the present invention, in the second lithium manganese composite oxide particulate composition, the ratio x of lithium atoms, the ratio y of oxygen atoms, and the first, second and third substitutions The ratios a, b and c at which the element replaces the manganese atom are respectively 0.8 ≦ x ≦ 1.2, 1.8 ≦ y ≦ 2.7, 0 <a ≦ 0.2, 0 ≦ b ≦ 0. It is a range that satisfies 20 <c ≦ 0.2.

In the first and second lithium manganese composite oxide particulate compositions according to the present invention, the first substitution element chromium is an element for controlling the intensity ratio R, and is mainly a monoclinic lithium manganese composite. It is an essential element for obtaining an oxide particulate composition. Although the reason is not necessarily clear, in the LiMnO ₂ crystal, a part of the position occupied by the manganese atom is occupied by the chromium atom. It is expected that the predominant crystal system will dominate the orthoclinic system and the unstable orthorhombic system will occupy the rest.

According to the present invention, the substitution amount a (molar fraction) of manganese atoms by chromium is 0.2 or less in 1 mol of manganese atoms in the lithium manganese composite oxide composition. That is, the amount of substitution of manganese atoms by chromium a
Is a range satisfying 0 <a ≦ 0.2, and preferably
The range is 0.03 ≦ a ≦ 0.1. If the amount of replacement of manganese atoms by chromium is too small, the cycle characteristics and charge / discharge capacity of a lithium ion secondary battery using the obtained lithium manganese composite oxide composition as a positive electrode active material will deteriorate. On the other hand, when the replacement amount of manganese atoms by chromium is too large, the lithium ion secondary battery exceeding the solid solubility limit and using such a composite oxide as a positive electrode active material is
The discharge capacity decreases.

According to the present invention, as described above, lithium mainly composed of a monoclinic crystal in which a part of manganese atoms is replaced by chromium (the intensity ratio R is in the range of 0 to 0.3). In the manganese composite oxide particulate composition, the cycle characteristics and capacity can be further improved by further substituting a part of the manganese atoms with the second substituting element M. Therefore, the second substituting element M, like the first substituting element chromium, is considered to contribute to stabilization of the crystal structure of the obtained lithium manganese composite oxide and contribute to improvement of characteristics.

According to the present invention, among the second substitution elements M, in particular, a lithium manganese composite oxide particulate composition using molybdenum is used as a positive electrode active material in a lithium ion secondary battery. This has the effect of stabilizing the discharge capacity of the battery in a high voltage region. That is, generally, in most cases, the discharge curve of a lithium ion secondary battery using lithium manganate as a positive electrode active material is a curve having two levels of flat portions in a region showing a voltage of 4 V and a region showing a voltage of 3 V. However, according to the present invention, a lithium manganese composite oxide particulate composition mainly composed of monoclinic crystals in which a part of manganese atoms is replaced by chromium and molybdenum is used as a positive electrode in a lithium ion secondary battery. When used as an active material, there is a characteristic that the discharge capacity in the 4 V region hardly changes even when charge and discharge are repeated.

According to the present invention, the substitution amount b (molar fraction) of the second substitution element M is in the range of 0 to 0.2 out of 1 mol of manganese atoms in the lithium manganese composite oxide composition. is there. That is, the substitution amount b of the manganese atom by the second substitution element M is in the range of 0 ≦ b ≦ 0.2, and preferably,
The range is 0.01 ≦ b ≦ 0.1. Second substitution element M
Is too large, the charge / discharge capacity of a lithium ion secondary battery using this as a positive electrode active material is reduced.

The second lithium manganese composite oxide particulate composition according to the present invention has a part of manganese atoms selected from the group consisting of In and W in addition to chromium and the second substitution element M. It is one that is substituted by at least one third substitution element N. This third substitution element N
Is a lithium-manganese composite oxide particulate composition mainly composed of a monoclinic crystal in which a part of manganese atoms is replaced by chromium (the intensity ratio R is in the range of 0 to 0.3).
This has the effect of stabilizing the initial discharge capacity of a lithium ion secondary battery using it as a positive electrode active material. That is, for example, the cycle characteristics of the lithium ion secondary battery using the lithium manganese composite oxide particulate composition not containing the third substitution element N as the positive electrode active material show a tendency that the capacity is initially decreased, By substituting a part of the manganese atoms with the third substitution element, such a decrease in capacity can be suppressed, and thus the second lithium manganese composite oxide particulate composition according to the present invention is used as a positive electrode active material. Thus, a lithium ion secondary battery having stable cycle characteristics from the beginning of the battery can be obtained.

According to the present invention, in the second lithium manganese composite oxide particulate composition, the substitution amount c (molar fraction) of manganese atoms by the third substituting element N is determined by the lithium manganese composite oxide composition. It is 0.2 or less in 1 mol of manganese atoms in the composition. That is, the substitution amount c of the manganese atom by the third substitution element N is in the range of 0 <c ≦ 0.2, and preferably in the range of 0.01 ≦ c ≦ 0.05. When the amount of manganese atoms replaced by the third replacement element N is too large, the solid solubility limit is exceeded, and the discharge capacity of a lithium ion secondary battery using such a composite oxide as a positive electrode active material is reduced.

The general formula (I) and the general formula (I
In the first and second lithium manganese composite oxide compositions according to the present invention represented by I), x is stoichiometrically 1, but some may deviate from the stoichiometric amount. In the lithium manganese composite oxide particulate composition according to the present invention, x can be in the range of 0.8 ≦ x ≦ 1.2. Whether lithium is more or less than the stoichiometric amount,
It can be suitably used as a positive electrode active material of a lithium ion secondary battery.

On the other hand, in the first lithium manganese composite oxide composition according to the present invention represented by the general formula (I), y is the above-mentioned values of x and b and the valence of the second substitution element M. The minimum value and the maximum value are determined as follows. That is, when x = 0.8, the valence of the second substitution element M is 2, and b = 0.2, the minimum value is obtained at y = 1.8, x = 1.2, the second substitution When the valence of the element M is 6, and b = 0.2, the maximum value is obtained at y = 2.4.

In the second lithium manganese composite oxide composition according to the present invention represented by the general formula (II), y is the above-mentioned values of x, b and c and the second substitution element M
And the valence of the third substitution element N. The minimum value and the maximum value are determined as follows.
That is, x = 0.8, the valence of the second substitution element M is 2, b =
0.2, the valence of the third substitution element N is 3, and when c is arbitrary, the minimum value is obtained at y = 1.8, x = 1.2, and the valence of the second substitution element M is 6, b = 0.2, third substitution element N
Takes the maximum value at y = 2.7 when the valence of is 6, and c = 0.2.

Next, the first and second lithium manganese composite oxide particulate compositions according to the present invention have a specific surface area of 0.5.
It is preferably in the range of 1 to 6.0 m ² / g,
It is particularly preferred that it is in the range of 1 to 2.0 m ² / g.
Here, in the present invention, the specific surface area means an automatic surface area measuring device (MONOSORBMS manufactured by Yuasa Ionics Inc.)
-15) indicates the value obtained by the BET one-point method.

When the specific surface area of the lithium manganese composite oxide particulate composition is smaller than 0.1 m ² / g, when the composition is used as a positive electrode active material of a lithium ion secondary battery,
There is a possibility that a large amount of electricity cannot be taken out rapidly. On the other hand, when the specific surface area exceeds 6.0 m ² / g, the amount of manganese eluted into the electrolyte in the lithium ion secondary battery increases, which may cause a problem of a decrease in charge / discharge capacity (cycling). There is.

The particulate lithium manganese oxide composition according to the present invention has a tap density of 1.4 to 2.4 g.
/ Cc. Here, in the present invention, the tap density means that 10 g of powder is collected in a measuring cylinder having a capacity of 50 mL and dropped 50 times vertically from a height of 50 mm on a horizontal and flat hard rubber plate. The volume V (cc) of the
V (g / cc).

As the tap density of the lithium manganese composite oxide particulate composition increases, the amount of the positive electrode active material occupying the volume of the lithium ion secondary battery increases, and there is an advantage that the charge / discharge capacity per volume can be increased. However, if only the tap density is to be increased, the reactivity of inserting and removing lithium ions into and from the positive electrode active material may be sacrificed.
In particular, according to the invention, the tap density is between 1.6 and 2.2.
It is preferably in the range of g / cc.

Further, the lithium manganese composite oxide particulate composition according to the present invention has a secondary particle having a particle diameter of 2 to 50 μm as observed by SEM (scanning electron micrograph) and a spherical particle shape. It is preferred that In the present invention, the particle diameter of one particle refers to the average value of the major axis and the minor axis, and the average particle diameter is the average of the particle diameters of 200 arbitrary particles in the SEM image.

When the particle diameter of the lithium manganese composite oxide particulate composition is smaller than 2 μm, the tap density decreases, and when used as a positive electrode active material of a lithium ion secondary battery, the filling amount per volume. And the charge / discharge capacity decreases. Conversely, if the particle size exceeds 50 μm, such particles may penetrate the separator between the positive and negative electrodes made of a polymer film such as polypropylene in a lithium ion secondary battery, causing a short circuit. In particular, according to the present invention, the particle diameter of the lithium manganese composite oxide particulate composition is preferably in the range of 2 to 50 µm, and most preferably in the range of 2 to 30 µm.

In the present invention, the shape of the particulate composition is not necessarily "spherical" when it is "spherical".
What is necessary is just to be "spherical" generally.

The first lithium manganese composite oxide particulate composition according to the present invention as described above comprises, as a first step, a lithium compound, a trivalent manganese compound, a chromium compound, and a compound of element M (manganese and chromium). Element M3
Of the compounds of one element, the compounds of two or more elements may be solid solution compounds. ) To obtain a mixture,
Next, as a second step, the mixture can be obtained by firing the mixture in an inert gas atmosphere.

Similarly, the second lithium manganese composite oxide particulate composition according to the present invention comprises, as a first step, a lithium compound, a trivalent manganese compound, a chromium compound, a compound of the element M, and a compound of the element N ( Among the compounds of the four elements of manganese, chromium, element M, and element N, compounds of two or more elements may be solid solution compounds) to obtain a mixture, and then, as a second step, This mixture can be obtained by firing in an inert gas atmosphere.

In the present invention, as described above, the reaction of firing the above mixture under an inert gas atmosphere to obtain a lithium manganese composite oxide particulate composition is hereinafter referred to as a lithiation reaction.

In the present invention, in the first step for producing the first and second lithium manganese composite oxide particulate compositions, the lithium compound may be a lithium manganese composite oxide finally intended. It is not particularly limited as long as it provides the composition, and for example, lithium acetate, an organic acid lithium such as lithium oxalate, lithium hydroxide, lithium carbonate, and an inorganic lithium salt such as lithium nitrate are used. . However,
From the viewpoint of price, operability, etc., as the lithium compound,
Lithium hydroxide, lithium carbonate or lithium nitrate is preferably used.

In the first step, the trivalent manganese compound is not particularly limited as long as it finally gives the intended lithium manganese composite oxide composition. Manganese (particularly, electrolytic manganese dioxide), manganese trioxide, manganese oxyhydroxide and the like are used. However, among these, manganese trioxide or manganese oxyhydroxide is preferably used from the viewpoints of cost and availability.

As is well known, the above manganese trioxide heats a manganese compound such as manganese dioxide, manganese carbonate, manganese sulfate or the like at a temperature of about 600 to 900 ° C. in the air or in an oxidizing atmosphere. Can be obtained by: Commercially available manganese trioxide can also be used.

The above manganese oxyhydroxide generally comprises
Although represented by MnOOH, more precisely, Mn ₂ O ₃ .H ₂
O. That is, manganese oxyhydroxide generally contains 1
It means manganese trioxide (Mn ₂ O ₃ ) having molecular water, but in the present invention, manganese trioxide may have less than one water molecule,
May be more than a molecule.

The above-mentioned manganese oxyhydroxide can be obtained by various methods as already known. For example, it can be obtained by neutralizing a compound having divalent manganese such as manganese nitrate, manganese chloride, and manganese sulfate with an alkali, and then oxidizing the compound with an oxidizing agent such as air, oxygen, and hydrogen peroxide. Further, for example, it can also be obtained by carbonating the aqueous solution of the above-mentioned divalent manganese compound, performing an alkali treatment, and finally performing an oxidation treatment. Commercially available manganese oxyhydroxide can also be used.

In the production of the lithium manganese composite oxide particulate composition according to the present invention, the chromium compound, the compound of the element M and the element N are also used as long as they finally give the desired lithium manganese composite oxide composition. There is no particular limitation, and appropriate ones are used.

Accordingly, specific examples of the chromium compound include, for example, chromium oxide, chromium hydroxide, chromium nitrate,
Specific examples of the compound of the element M include chromium sulfate and chromium acetate, for example, aluminum hydroxide, aluminum nitrate, aluminum sulfate, aluminum acetate, boric acid, magnesium hydroxide, magnesium carbonate, magnesium chloride, magnesium acetate, pentoxide Vanadium, ammonium metavanadate, iron hydroxide, iron nitrate, iron sulfate, iron chloride, cobalt hydroxide, cobalt nitrate, cobalt sulfate, cobalt chloride, nickel hydroxide, nickel nitrate, nickel sulfate, yttrium oxide, yttrium nitrate, molybdenum oxide Element N, ruthenium chloride, tin oxide, tin chloride, antimony chloride, cerium oxide, cerium nitrate, praseodymium nitrate, neodymium chloride, europium acetate, hafnium chloride, tantalum chloride, lead sulfate, lead acetate, lead chloride, etc. Compound As the body example, indium oxide,
Indium sulfate, indium chloride, tungsten oxide,
Examples thereof include oxides such as tungsten chloride, hydroxides, inorganic salts, and organic salts.

As described above, according to the present invention, in the production of the first lithium manganese composite oxide particulate composition, in the first step, the lithium compound, the trivalent manganese compound, the chromium compound and the element M Compounds (mixtures of two or more of the three compounds of manganese, chromium, and element M may be solid solution compounds) are mixed to obtain a mixture. In the production of the second lithium manganese composite oxide particulate composition, in the first step, a lithium compound, a trivalent manganese compound, a chromium compound, a compound of the element M, and a compound of the element N (manganese and chromium Among the compounds of the four elements, element M and element N,
The compound of two or more elements may be a solid solution compound. ) To obtain a mixture.

Therefore, the first and second lithium manganese
In the production of the composite oxide particulate composition, the first step
When mixing each of the above compounds,
Is possible. However, according to the present invention, the first
In the production of lithium manganese composite oxide particulate composition
Especially trivalent manganese compounds and chromium compounds
And a compound of the element M, and then fired in the atmosphere,
A solid solution oxide, which is mixed with a lithium compound,
Preferably, a mixture is obtained. According to this aspect, trivalent
Homogeneous solution of manganese atom, element Cr and element M
Compound can be obtained. Such a solid solution oxide
For example, (Mn_1-abCr_aM_b) _TwoO_yExamples
can do. Where y is a solid solution oxide
And the valence of element M together with the value of b so that
It is a value determined.

Similarly, in the production of the second lithium manganese composite oxide particulate composition, the trivalent manganese compound, the chromium compound, the compound of the element M, and the element N
After the above compound is mixed, it is preferable that the mixture is fired in the air to form a solid solution oxide, which is mixed with a lithium compound to obtain a mixture. According to this aspect, a uniform solid solution oxide of trivalent manganese atom, element Cr, element M, and element N can be obtained. As such a solid solution oxide, for example, (Mn _{1 -abc C a} M _b N _c ) ₂ O _y can be exemplified. Here, y is an element M together with the values of b and c so as to make the solid solution oxide electrically neutral.
And the valence of the element N.

Hereinafter, the production of the first and second lithium manganese composite oxide particulate compositions will be described in common.
The description in parentheses shows the case where the second lithium manganese composite oxide particulate composition is produced.

The method of obtaining such a solid solution oxide of trivalent manganese atom, chromium, and element M (and element N) is not particularly limited. For example, a chromium compound (eg, nitrate, acetic acid) An aqueous solution of a compound of element M (eg, nitrate, acetate, hydroxide, etc.) and a compound of element N (eg, sulfate, chloride, oxide, etc.) with manganese carbonate The chromium compound and the compound of the element M (and the compound of the element N) are adhered to the surface of the manganese carbonate particles while stirring, and the mixture is baked in the air. Obtainable.

As another method, for example, a compound of manganese carbonate particles, a chromium compound and an element M (and an element N
And the compound of the above) is mixed, and a compound of these elements is applied to the surface of the manganese carbonate particles.
The particles can also be obtained by producing excessively advanced sintering particles and subsequently firing them again in an oxidizing atmosphere.

As described above, after the first step is carried out to obtain a mixture, the second step is such that the mixture is calcined in an inert gas atmosphere to carry out a lithiation reaction, thereby obtaining a mixture according to the present invention. The first or second lithium manganese composite oxide particulate composition can be obtained.

According to the present invention, in the second step, the mixture is calcined in an inert gas atmosphere so that the valence of trivalent manganese does not change by an oxidation or reduction reaction. In the second step, if the valence of trivalent manganese changes by an oxidation or reduction reaction, the lithium manganese composite oxide particulate composition according to the present invention cannot be obtained.

As the above-mentioned inert gas, for example, helium, nitrogen, argon and the like are used, and nitrogen gas is preferably used from an economic viewpoint. However, any inert gas can be used as long as it forms an atmosphere that does not cause a change in the valence of trivalent manganese.

In the second step, the firing temperature of the mixture is
In the range of 300 ° C. to 1000 ° C., preferably 4 ° C.
It is in the range of 70 ° C to 900 ° C. Sintering temperature is 300 ℃
If lower, the lithiation reaction will be incomplete. On the other hand, when the firing temperature is higher than 1000 ° C., the primary particles of the obtained composite oxide particulate composition grow excessively,
When used as a positive electrode active material of a lithium ion secondary battery, it is difficult for lithium to enter and exit the positive electrode, and it is difficult to obtain a battery having satisfactory characteristics.

In the second step, the optimum value of the sintering temperature and the product, ie, the crystal phase of the lithium manganese composite oxide composition, vary depending on the type of the substitution element used. For example, when no substitution element is used, 470 ° C. to 900 ° C.
An orthorhombic composite oxide composition is produced in the entire temperature range of. When a part of the manganese atom is replaced with a chromium atom, only a monoclinic composite oxide composition is generated, or a monoclinic and orthorhombic composite oxide composition is generated, and the firing temperature is reduced. The higher is the higher the percentage of monoclinic.

The lithium ion secondary battery according to the present invention
The lithium manganese composite oxide particulate composition thus obtained is used as a positive electrode active material.

FIG. 1 shows an example of a lithium ion secondary battery using a non-aqueous electrolyte (organic electrolyte). Positive electrode 1 and negative electrode 2
Are housed in a battery container 4 so as to face each other via a separator 3 impregnated with a non-aqueous electrolyte, and the positive electrode 1 is connected to a positive electrode lead wire 6 via a positive electrode current collector 5. ,
The negative electrode 2 is connected to a negative electrode lead wire 8 through a negative electrode current collector 7.
, So that the chemical energy generated inside the battery can be extracted to the outside as electric energy from the lead wires 6 and 8.

The lithium manganese composite oxide particulate composition according to the present invention is mixed with a conductive agent, a binder, a filler, and the like, and kneaded to form a mixture (paste). Is applied to the positive electrode current collector, pressure-bonded, and dried by heating under reduced pressure to obtain a positive electrode. However, if necessary, the above mixture may be press-molded into an appropriate shape such as a disc shape, and if necessary, heat-treated under vacuum to form a positive electrode.

The conductive agent is not particularly limited as long as it does not cause a chemical change in a lithium ion secondary battery. Therefore, examples of the conductive agent include conductive polymer substances such as natural graphite, artificial graphite, carbon black, Ketjen black, carbon fiber, metal powder, metal fiber, and polyphenylene. These may be used alone or in combination of two or more. The amount of the conductive agent is not particularly limited, but is usually in the range of 1 to 50% by weight in the above mixture.
Preferably, it is in the range of 2 to 30% by weight.

The binder is not particularly limited either.
Starch, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, regenerated cellulose, diacetyl cellulose, polyvinyl chloride, polyvinyl pyrrolidone, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, ethylene-propylene-diene rubber (EPDM), sulfonated EPDM Styrene-butadiene rubber, polybutadiene, fluorine rubber, polyethylene oxide and the like. These may be used alone or in combination of two or more. The blending amount of the binder is also not particularly limited, but is usually preferably in the range of 1 to 50% by weight, particularly preferably in the range of 2 to 30% by weight in the above mixture.

The above-mentioned filler is mixed with the mixture as required. The filler is not particularly limited as long as it is a fibrous material that does not cause a chemical change in a lithium ion secondary battery, and a conventionally known filler is appropriately used. Accordingly, examples of such a filler include polyolefin resin fibers such as polypropylene resin and polyethylene resin, glass fibers, carbon fibers, and the like. The amount of the filler is not particularly limited, but is usually in the range of 0 to 30% by weight in the above mixture.

In the lithium ion secondary battery according to the present invention, the negative electrode material is not particularly limited as long as it is conventionally used for lithium ion secondary batteries. An alloy or a carbon material capable of occluding and releasing lithium ions is used.

The positive electrode and the negative electrode are usually formed on a current collector. The current collector is not particularly limited, but usually, stainless steel or its mesh is used.

The non-aqueous electrolyte may be any known one as long as it is conventionally known. Examples thereof include ethylene carbonate (EC), propylene carbonate, dimethyl carbonate (DMC), and diethyl carbonate. Carbonates, sulfolanes, lactones,
In an organic solvent such as ethers such as 1,2-dimethoxyethane, 1,2-diethoxyethane, ethoxymethoxyethane and the like, lithium perchlorate (LiClO ₄ ) and lithium hexafluorophosphate (LiPF ₆ ) Examples thereof include those in which dissociable lithium salts are dissolved. As the separator, for example, a porous film made of a polyolefin resin such as polyethylene or polypropylene is used, but it is not limited thereto.

The lithium ion secondary battery according to the present invention
For example, it can be suitably used for portable electronic devices such as a notebook computer, a mobile phone, and a video movie.
It can also be applied as a large-sized battery such as a battery mounted on a moving body and an auxiliary power source for home use.

[0073]

EXAMPLES The present invention will be described below with reference to examples.
The present invention is not limited by these examples.

Example 1 Manganese carbonate (spherical, average particle size 10 μm) 105.75
g, chromium nitrate nonahydrate 20.01 g and cobalt sulfate heptahydrate 8.43 g (molar ratio Cr / (Mn + Cr + Co)
= 0.05, molar ratio Co / (Mn + Cr + Co) = 0.
03) into a 500 mL beaker, 250 m
L of water was added and stirred, uniformly mixed and dispersed to obtain a slurry. While stirring, heat this slurry,
The water was evaporated to dryness and then dried overnight in an electric dryer. The obtained mass was pulverized to obtain manganese carbonate particles having chromium nitrate and cobalt sulfate adhered to the surface.
Next, manganese carbonate particles having chromium nitrate and cobalt sulfate adhered to the surface in this way are put into an alumina crucible,
After calcination in air at 1150 ° C for 4 hours, it is cooled and pulverized, and further baked in an oxygen atmosphere at 800 ° C for 10 hours to replace 5 mol% of chromium and 3 mol% of cobalt with respect to manganese atoms. A solid solution manganese oxide powder was obtained. X
As a result of X-ray diffraction measurement, manganese trioxide Mn ₂ O ₃ (JC
PDS card No. 41-1442).

Next, the chromium and cobalt solid solution
7.89 g of manganese dioxide powder and lithium hydroxide monohydrate
In a mortar (molar ratio Li / (Mn + Cr)
+ Co) = 1.00) and mixed uniformly. The resulting mixture
The product is placed in an alumina crucible and placed in a nitrogen atmosphere at 575 ° C.
Firing for 15 hours, chromium 5
Lithium and manganese complex substituted with 3 mol% of cobalt
Compound oxide (LiMn_{0. 92}Cr_0.05Co_0.03O_TwoGet)
Was. This product is ground in a sample mill for about 20 seconds,
Dissolve the cohesion between the secondary particles to form the lithium man
A gun composite oxide particulate composition was obtained.

Example 2 Manganese carbonate (spherical, average particle size 10 μm) 105.75
g, 20.01 g of chromium nitrate nonahydrate and 8.72 g of nickel nitrate hexahydrate (molar ratio: Cr / (Mn + Cr + Ni)
= 0.05, molar ratio Ni / (Mn + Cr + Ni) = 0.
03) in the same manner as in Example 1 to obtain a solid manganese dioxide powder in which 5 mol% of chromium and 3 mol% of nickel were substituted and dissolved in manganese atoms. 7.89 g of this manganese sesquioxide powder in which chromium and nickel were dissolved, and 4.20 g of lithium hydroxide monohydrate were placed in a mortar (molar ratio Li / (Mn + Cr + Ni) = 1.00) and uniformly mixed. The resulting mixture is placed under a nitrogen atmosphere at 575 ° C. for 15 minutes.
After firing for 5 hours, 5 mol% of chromium based on manganese atoms
And a lithium-manganese composite oxide (LiMn _0.92 Cr _0.05 Ni _0.03 O ₂ ) substituted with 3 mol% of nickel. This product was pulverized with a sample mill for about 20 seconds to disperse the secondary particles from each other to obtain a lithium manganese composite oxide particulate composition according to the present invention.

FIG. 2 shows an X-ray diffraction chart of the lithium manganese composite oxide particulate composition (the X-ray source was CuK
α ray).

Example 3 Manganese carbonate (spherical, average particle size 10 μm) 105.75
g, chromium nitrate nonahydrate 20.01 g and ammonium molybdate tetrahydrate 5.30 g (molar ratio Cr / (Mn +
Cr + Mo) = 0.05, molar ratio Mo / (Mn + Cr +)
Mo) = 0.03), and manganese trioxide powder was obtained in the same manner as in Example 1 by substituting 5 mol% of chromium and 3 mol% of molybdenum with manganese atoms for solid solution. 8.00 g of this manganese trioxide powder in which chromium and molybdenum are dissolved and 4.20 g of lithium hydroxide monohydrate
(Molar ratio Li / ((Mn + Cr + Mo) = 1.00) was placed in a mortar and mixed uniformly. The resulting mixture was calcined at 610 ° C. for 15 hours under a nitrogen atmosphere, and chromium 5 Lithium-manganese composite oxide (LiMn _0.92 Cr _0.05
Mo _0.03 O ₂ ) was obtained. This product was pulverized with a sample mill for about 20 seconds to disperse the secondary particles from each other to obtain a lithium manganese composite oxide particulate composition according to the present invention.

Example 4 Manganese carbonate (spherical, average particle size 10 μm) 105.75
g, chromium nitrate nonahydrate 20.01 g and europium acetate 11.49 g (molar ratio Cr / (Mn + Cr + Eu) =
0.05, molar ratio Eu / (Mn + Cr + Eu) = 0.0
In the same manner as in Example 1, using 3), manganese trioxide powder was obtained in which 5 mol% of chromium and 3 mol% of europium were substituted and dissolved in manganese atoms. 8.17 powder of manganese sesquioxide in which chromium and europium are dissolved.
g and lithium hydroxide monohydrate 4.20 g (molar ratio Li /
(Mn + Cr + Eu) = 1.00) was placed in a mortar and mixed uniformly. The obtained mixture is heated at 610 ° C. under a nitrogen atmosphere.
And baked for 15 hours.
Lithium manganese composite oxide (LiMn _0.92 Cr _0.05 Eu _0.03 O ₂ ) substituted with 3 mol% of europium by mol%
I got This product was pulverized with a sample mill for about 20 seconds to disperse the secondary particles from each other to obtain a lithium manganese composite oxide particulate composition according to the present invention.

Example 5 Manganese carbonate (spherical, average particle size 10 μm) 105.75
g, chromium nitrate nonahydrate 20.01 g, and tungsten oxide 4.64 g (molar ratio Cr / (Mn + Cr + W) = 0.
05, using the molar ratio W / (Mn + Cr + W) = 0.02), in the same manner as in Example 1,
A manganese trioxide powder obtained by displacing 5 mol% of chromium and 2 mol% of tungsten in a solid solution was obtained. 8.14 g of this manganese sesquioxide powder having a solid solution of chromium and tungsten and 4.20 g of lithium hydroxide monohydrate (molar ratio Li / ((Mn +
(Cr + W) = 1.00) was placed in a mortar and mixed uniformly. The obtained mixture was calcined at 610 ° C. for 15 hours under a nitrogen atmosphere, and lithium manganese composite oxide (LiMn _0.93 Cr _0.05 W _0.02 O _{2) in which} 5 mol% of chromium and 2 mol% of tungsten were substituted for manganese atoms. ) Got. This product was pulverized with a sample mill for about 20 seconds to disperse the secondary particles from each other to obtain a lithium manganese composite oxide particulate composition according to the present invention.

FIG. 2 shows an X-ray diffraction chart of the lithium manganese composite oxide particulate composition (the X-ray source was CuK
α ray).

Example 6 105.75 g of manganese carbonate (spherical, particle size: 10 μm), 20.01 g of chromium nitrate nonahydrate, 4.64 g of tungsten oxide and 3.75 g of aluminum nitrate nonahydrate (molar ratio: Cr / ( (Mn + Cr + W + Al) = 0.05, molar ratio W / (Mn + Cr + W + Al) = 0.02, molar ratio A
1 / (Mn + Cr + W + Al) = 0.01)
In the same manner as in Example 1, a manganese trioxide powder in which 5 mol% of chromium, 2 mol% of tungsten, and 1 mol% of aluminum were substituted with manganese atoms for solid solution was obtained. 3.11 g of manganese sesquioxide powder obtained by dissolving chromium, tungsten and aluminum and lithium hydroxide monohydrate
20 g (molar ratio Li / (Mn + Cr + W + Al) = 1.
00) was placed in a mortar and mixed homogeneously. The obtained mixture was calcined at 610 ° C. for 15 hours under a nitrogen atmosphere, and a lithium manganese composite oxide (LiMn _0.92 Cr) in which 5 mol% of chromium, 2 mol% of tungsten and 1 mol% of aluminum were substituted for manganese atoms. _0.05 W _0.02 Al
_0.01 O ₂ ). This product is put in a sample mill for about 20
The mixture was pulverized for 2 seconds to disperse the secondary particles from each other to obtain a lithium manganese composite oxide particulate composition according to the present invention.

Example 7 Manganese carbonate (spherical, average particle size 10 μm) 105.75
g, chromium nitrate nonahydrate 20.01 g, tungsten oxide 4.64 g, and yttrium acetate tetrahydrate 3.38 g
(Molar ratio Cr / (Mn + Cr + W + Y) = 0.05, molar ratio W / (Mn + Cr + W + Y) = 0.02, molar ratio Y
/(Mn+Cr+W+Y)=0.01) in the same manner as in Example 1 by replacing 5 mol% of chromium, 2 mol% of tungsten and 1 mol% of yttrium with manganese atoms and forming a solid solution. I got a body. 8.17 g of manganese trioxide powder obtained by dissolving chromium, tungsten and yttrium and lithium hydroxide monohydrate 4.20
g (molar ratio Li / (Mn + Cr + W + Y) = 1.00)
Was placed in a mortar and mixed evenly. The obtained mixture was calcined at 610 ° C. for 15 hours under a nitrogen atmosphere, and a lithium manganese composite oxide (LiMn _0.92 Cr) in which 5 mol% of chromium, 2 mol% of tungsten and 1 mol% of yttrium were substituted for manganese atoms. _0.05 W _0.02 Y _0.01 O ₂ ). This product was pulverized with a sample mill for about 20 seconds to disperse the secondary particles from each other to obtain a lithium manganese composite oxide particulate composition according to the present invention.

Example 8 Manganese carbonate (spherical, average particle size 10 μm) 105.75
g of chromium nitrate nonahydrate, 4.64 g of tungsten oxide and ammonium molybdate tetrahydrate.
77 g (molar ratio Cr / (Mn + Cr + W + Mo) = 0.
05, molar ratio W / (Mn + Cr + W + Mo) = 0.0
2, molar ratio Mo / (Mn + Cr + W + Mo) = 0.0
Using 1), a manganese trioxide powder was obtained in the same manner as in Example 1 except that 5 mol% of chromium, 2 mol% of tungsten, and 1 mol% of molybdenum were substituted and dissolved in manganese atoms. 8.18 g of this manganese trioxide powder in which chromium, tungsten, and molybdenum are dissolved and 4.20 g of lithium hydroxide monohydrate (molar ratio Li / (Mn + Cr + W + M)
o) = 1.00) was placed in a mortar and mixed homogeneously. The obtained mixture was calcined at 610 ° C. for 15 hours under a nitrogen atmosphere, and lithium manganese composite oxide (LiMn _0.92 Cr) in which chromium 5 mol%, tungsten 2 mol% and molybdenum 1 mol% were substituted for manganese atoms. _0.05 W _0.02 Mo
_0.01 O ₂ ). This product is put in a sample mill for about 20
The mixture was pulverized for 2 seconds to disperse the secondary particles from each other to obtain a lithium manganese composite oxide particulate composition according to the present invention.

Example 9 Manganese carbonate (spherical, average particle size 10 μm) 105.75
g of chromium nitrate nonahydrate and 2.78 g of indium oxide (molar ratio: Cr / (Mn + Cr + In) = 0.
05, molar ratio In / (Mn + Cr + In) = 0.02)
In the same manner as in Example 1, manganese trioxide powder was obtained in which 5 mol% of chromium and 2 mol% of indium were substituted and dissolved in manganese atoms. 8.00 g of this manganese sesquioxide powder in which chromium and indium were dissolved, and 4.20 g of lithium hydroxide monohydrate (molar ratio Li / (Mn + C)
(r + In) = 1.00) was placed in a mortar and mixed uniformly. The obtained mixture was calcined at 610 ° C. for 15 hours under a nitrogen atmosphere, and lithium manganese composite oxide (LiMn _0.93 Cr _0.05 In _0.02 O _{2) in which} 5 mol% of chromium and 2 mol% of indium were substituted for manganese atoms. ) Got. This product was pulverized with a sample mill for about 20 seconds to disperse the secondary particles from each other to obtain a lithium manganese composite oxide particulate composition according to the present invention.

Example 10 Manganese carbonate (spherical, average particle size 10 μm) 105.75
g, chromium nitrate nonahydrate, 20.01 g, indium oxide, 2.78 g, and ammonium vanadate 1.17 g (molar ratio Cr / (Mn + Cr + In + V) = 0.05, molar ratio In / (Mn + Cr + In + V) = 0.02, mol) Ratio V
/(Mn+Cr+In+V)=0.01) in the same manner as in Example 1 with respect to the manganese atom.
Thus, a manganese sesquioxide powder was obtained in which a solid solution was prepared by substituting mol%, indium 2 mol% and vanadium 1 mol%. 8.00 g of this manganese trioxide powder having a solid solution of chromium, indium and vanadium and 4.20 g of lithium hydroxide monohydrate
(Molar ratio Li / (Mn + Cr + In + V) = 1.00)
Was placed in a mortar and mixed evenly. The obtained mixture was calcined at 610 ° C. for 15 hours under a nitrogen atmosphere, and a lithium manganese composite oxide (LiMn _0.92 Cr) in which 5 mol% of chromium, 2 mol% of indium and 1 mol% of vanadium were substituted for manganese atoms. _0.05 In _0.02 V _0.01 O ₂ ).
This product was pulverized with a sample mill for about 20 seconds to disperse the secondary particles from each other to obtain a lithium manganese composite oxide particulate composition according to the present invention.

Example 11 Manganese carbonate (spherical, average particle size 10 μm) 105.75
g, 20.01 g of chromium nitrate nonahydrate, 2.78 g of indium oxide, and 2.91 g of nickel nitrate hexahydrate (molar ratio: Cr / (Mn + Cr + In + Ni) = 0.05, molar ratio: In / (Mn + Cr + In + Ni) = 0. 02, a molar ratio of Ni / (Mn + Cr + In + Ni) = 0.01) and 5 mol% of chromium, 2 mol% of indium and 1 mol% of nickel with respect to manganese atoms in the same manner as in Example 1.
Was obtained as a solid solution. 7. Manganese sesquioxide in which chromium, indium and nickel are dissolved 8.
00 g and lithium hydroxide monohydrate 4.20 g (molar ratio L
i / (Mn + Cr + In + Ni) = 1.00) was placed in a mortar and mixed uniformly. The obtained mixture was calcined at 610 ° C. for 15 hours under a nitrogen atmosphere to obtain 5 mol% of chromium, 2 mol% of indium, and 1 mol of nickel based on manganese atoms.
Mol% substituted lithium manganese composite oxide (LiM
n _0.92 Cr _0.05 In _0.02 Ni _0.01 O ₂ ). This product was pulverized with a sample mill for about 20 seconds to disperse the secondary particles from each other to obtain a lithium manganese composite oxide particulate composition according to the present invention.

Example 12 Manganese carbonate (spherical, average particle size 10 μm) 105.75
g, chromium nitrate nonahydrate 20.01 g, indium oxide 2.78 g, and ammonium molybdate tetrahydrate 1.7
8 g (molar ratio: Cr / (Mn + Cr + In + Mo) = 0.
05, molar ratio In / (Mn + Cr + In + Mo) = 0.
02, molar ratio Mo / (Mn + Cr + In + Mo) = 0.
01), a manganese trioxide powder was obtained in the same manner as in Example 1 except that 5 mol% of chromium, 2 mol% of indium, and 1 mol% of molybdenum were substituted and dissolved in manganese atoms. 8.04 g of this manganese trioxide powder in which chromium, indium and molybdenum are dissolved, and 4.20 g of lithium hydroxide monohydrate (molar ratio Li / (Mn + Cr + In + M)
o) = 1.00) was placed in a mortar and mixed homogeneously. The obtained mixture was calcined at 610 ° C. for 15 hours under a nitrogen atmosphere, and lithium manganese composite oxide (LiMn _0.92 Cr) in which 5 mol% of chromium, 2 mol% of indium and 1 mol% of molybdenum were substituted for manganese atoms. _0.05 In _0.02 Mo
_0.01 O ₂ ). This product is put in a sample mill for about 20
The mixture was pulverized for 2 seconds to disperse the secondary particles from each other to obtain a lithium manganese composite oxide particulate composition according to the present invention.

Example 13 Manganese carbonate (spherical, average particle size 10 μm) 105.75
g, chromium nitrate nonahydrate 20.01 g, indium oxide 2.78 g, and tungsten oxide 2.32 g (molar ratio Cr
/(Mn+Cr+In+W)=0.05, molar ratio In /
(Mn + Cr + In + W) = 0.02, molar ratio W / (M
Example 1 using (n + Cr + In + W) = 0.01)
In the same manner as above, chromium is 5 mol% based on manganese atoms.
And 2 mol% of indium and 1 mol% of tungsten were substituted to obtain a solid solution of manganese trioxide. 8.13 g of this manganese sesquioxide powder in which chromium, indium and tungsten are dissolved, and 4.20 g of lithium hydroxide monohydrate (molar ratio Li / (Mn + Cr + In + W) = 1.00) are placed in a mortar and mixed uniformly. did. The obtained mixture was calcined at 610 ° C. for 15 hours under a nitrogen atmosphere, and a lithium manganese composite oxide (L) in which 5 mol% of chromium, 2 mol% of indium and 1 mol% of tungsten were substituted for manganese atoms.
iMn _0.92 Cr _0.05 In _0.02 W _0.01 O ₂ ) was obtained. This product was pulverized with a sample mill for about 20 seconds to disperse the secondary particles from each other to obtain a lithium manganese composite oxide particulate composition according to the present invention.

Comparative Example 1 Manganese carbonate (spherical, average particle size 10 μm) 114.95
g in an alumina crucible and fired in the air at 1150 ° C. for 4 hours, then cooled, pulverized the obtained lump, and further fired in an oxygen atmosphere at 800 ° C. for 10 hours to obtain manganese trioxide A powder was obtained. 7.89 g of this manganese trioxide powder and 4.20 g of lithium hydroxide monohydrate (molar ratio Li / Mn = 1.00) were placed in a mortar, mixed uniformly, and then mixed at 575 ° C. in a nitrogen atmosphere at 575 ° C. After calcination for a time, a lithium manganese composite oxide (LiMnO ₂ ) was obtained. This product was pulverized with a sample mill for about 20 seconds to disperse the secondary particles from each other to obtain a lithium manganese composite oxide particulate composition according to a comparative example.

FIG. 2 shows an X-ray diffraction chart of the lithium-manganese composite oxide (the X-ray source is CuKα ray).

Comparative Example 2 Manganese carbonate (spherical, average particle size 10 μm) 111.50
g and nickel nitrate hexahydrate 8.72 g (molar ratio Ni /
Using (Mn + Ni) = 0.03), a manganese trioxide powder in which 3 mol% of nickel was substituted and dissolved in manganese atoms was obtained in the same manner as in Example 1. 7.91 g of this manganese trioxide powder having nickel dissolved therein and 4.20 g of lithium hydroxide monohydrate (molar ratio Li / (Mn + N
i) = 1.00) was placed in a mortar, mixed uniformly, and then calcined at 575 ° C. for 15 hours under a nitrogen atmosphere to replace lithium manganese composite oxide (3 mol% of nickel with respect to manganese atoms). LiMn _0.97 Ni _0.03 O ₂ ) was obtained.
This product was pulverized with a sample mill for about 20 seconds to disperse the secondary particles from each other to obtain a lithium manganese composite oxide particulate composition according to a comparative example.

Comparative Example 3 Manganese carbonate (spherical, average particle size 10 μm) 111.50
g and 5.30 g of ammonium molybdate tetrahydrate (molar ratio Mo / (Mn + Mo) = 0.03), 3% by mole of molybdenum was substituted with manganese atom in the same manner as in Example 1. A dissolved manganese trioxide powder was obtained.
This molybdenum solid solution of manganese trioxide powder 8.0
2 g and lithium hydroxide monohydrate 4.20 g (molar ratio Li
/(Mn+Mo)=1.00) is placed in a mortar, mixed uniformly, and then calcined at 610 ° C. for 15 hours in a nitrogen atmosphere to replace lithium manganese with 3 mol% of molybdenum with respect to manganese atoms. (LiMn _0.97 Mo
_0.03 O ₂ ). This product is put in a sample mill for about 20
The mixture was crushed for 2 seconds to disperse the secondary particles from each other to obtain a lithium manganese composite oxide particulate composition according to a comparative example.

The substitution element species in each lithium manganese composite oxide composition according to Examples 1 to 13 and Comparative Examples 1 to 3, the substitution amount thereof, the stoichiometric ratio of lithium and the firing temperature are shown in Table 1. Table 2 shows the crystal phase, strength ratio R, tap density, specific surface area, and SEM average particle size of each lithium manganese composite oxide composition. Here, the intensity ratio R
Is the intensity ratio I (rhombic) / I in the X-ray diffraction chart.
(Monoclinic), that is, LiMnO ₂ (JCPDS card N
o. 35-0749) (010) plane and LiMnO
₂ (M. Tabuchi et al., J. Electrochem. Soc., Vol.
145, L49) of the (001) plane. The identification of the crystal phase is performed using a powder X-ray diffractometer (Rigaku Denki Co., Ltd. R
AD2C, X-ray source CuKα ray).

[0095]

[Table 1]

[0096]

[Table 2]

Example 14 A lithium ion secondary battery for testing using each of the lithium manganese composite oxide particulate compositions obtained in Example 2, Example 5, Example 9 and Comparative Example 1 as a positive electrode active material. Was prepared, and the battery characteristics were evaluated.

That is, each active material was uniformly mixed in a mortar with acetylene black (conductive agent) and polytetrafluoroethylene resin (binder) to prepare a mixture. This was punched out into a disk having a diameter of 16 mm by a pressure press, and vacuum-dried to obtain a positive electrode. A metal lithium foil was used as the negative electrode, and a polypropylene resin film (Certgard) was used as the separator. Electrolyte is EC / DM
Lithium perchlorate was dissolved and dissolved in a C (1/1) mixture at a concentration of 1 mol / L, and this was impregnated into a separator. These components were assembled into a lithium ion secondary battery for a charge / discharge test as shown in FIG.

A charge / discharge test was performed on each of the batteries assembled as described above. The charge and discharge conditions were a current density of 0.2 mA / cm ² , a cutoff voltage of an upper limit of 4.3 V,
The lower limit was 2.0V. FIG. 3 shows the transition of the discharge capacity, that is, the cycle characteristics.

In the lithium ion secondary battery using the lithium manganese composite oxide particulate composition according to the present invention as a positive electrode active material, any of the discharge capacities was almost the same as the initial capacity even after 20 cycles, and a high discharge capacity was obtained. Holding capacity. In particular, the lithium ion secondary battery using the lithium manganese composite oxide particulate composition according to Example 5 as a positive electrode active material has a stable initial discharge capacity.

[0101]

As described above, according to the lithium ion secondary battery using the lithium manganese composite oxide particulate composition according to the present invention as a positive electrode active material, a high discharge capacity can be obtained, and moreover, each cycle can be obtained. Discharge capacity is stable.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a lithium ion secondary battery.

FIG. 2 is an X-ray diffraction chart of a lithium manganese composite oxide particulate composition according to Example 2, Example 5, and Comparative Example 1.

FIG. 3 is a graph showing a discharge capacity per cycle of a lithium ion secondary battery using a lithium manganese composite oxide particulate composition according to the present invention as a positive electrode active material,
7 shows the discharge capacity of each cycle of a lithium ion secondary battery using a lithium manganese composite oxide particulate composition according to a comparative example as a positive electrode active material.

[Explanation of symbols]

 1: Positive electrode 2: Negative electrode 3: Separator 4: Battery container 5: Positive current collector 6: Positive lead wire 7: Negative current collector 8: Negative lead wire

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H01M 10/40 H01M 10/40 Z (72) Inventor Seiichi Yano 5-1-1 Ebisshima-cho, Sakai-shi, Osaka Sakai Chemical Co., Ltd. In-house F-term (reference) 4G048 AA04 AA05 AB01 AB05 AC06 AD04 AD06 AE05 5H029 AJ03 AJ05 AK03 AL06 AL12 AM02 AM03 AM04 AM07 CJ02 CJ08 CJ28 DJ16 DJ17 EJ04 EJ12 HJ02 HJ05 HJ07 HJ08 HJ13 5H050 AA07 FAB07A17A07A17A GA10 GA27 HA02 HA05 HA07 HA08 HA13

Claims (10)

[Claims] 1. A compound of the general formula (I) Li _x Mn _1-ab C _a M _b O _{y wherein} M is B, Mg, Al, Si, Sc, Ti, V,
Fe, Co, Ni, Cu, Zn, Ga, Y, Zr, N
b, Mo, Ru, Sn, Sb, Hf, Ta, Pb and at least one element selected from the group consisting of rare earth elements, wherein x, y, a and b are respectively 0.8 ≦ x ≦ 1. 2, 1.8 ≦ y ≦ 2.4, 0 <a ≦ 0.2, and 0 ≦ b ≦ 0.2. A) a composite oxide represented by
A composite oxide having a monoclinic crystal system or a mixture of a composite oxide having a monoclinic crystal system and a composite oxide having an orthorhombic crystal system. (Orthorhombic)
/ I (monoclinic) wherein the intensity ratio R is in the range of 0 to 0.3. 2. The general formula (II): Li _x Mn _{1-ab C a} M _b N _c O _y (where M is B, Mg, Al, Si, Sc, Ti, V,
Fe, Co, Ni, Cu, Zn, Ga, Y, Zr, N
b, Mo, Ru, Sn, Sb, Hf, Ta, Pb and at least one element selected from the group consisting of rare earth elements; N represents at least one element selected from the group consisting of In and W; , X, y, a, b and c are respectively 0.8 ≦ x ≦ 1.2, 1.8 ≦ y ≦ 2.7, 0 <a ≦ 0.2, 0 ≦ b ≦ 0.2, 0 <C ≦ 0.2. A) a composite oxide represented by
A composite oxide having a monoclinic crystal system or a mixture of a composite oxide having a monoclinic crystal system and a composite oxide having an orthorhombic crystal system. (Orthorhombic)
/ I (monoclinic), wherein the intensity ratio R defined in the range of 0 to 0.3 is a lithium manganese composite oxide particulate composition. 3. The lithium manganese composite oxide particulate composition according to claim 1, wherein M is at least one element selected from the group consisting of Al, V, Co, Ni, Y, Mo and Eu. . 4. The lithium manganese composite oxide particulate composition according to claim 1, which has a specific surface area of 0.1 to 6.0 m ² / g. 5. The lithium manganese composite oxide particulate composition according to claim 1, having a tap density of 1.4 to 2.4 g / cc. 6. A secondary particle having a particle size of 2 to 2 as observed by SEM observation.
The lithium manganese composite oxide particulate composition according to any one of claims 1 to 3, wherein the composition is in a range of 50 µm and the shape of the particles is spherical. 7. A compound of a lithium compound, a trivalent manganese compound, a chromium compound and an element M (a compound of two or more elements of a compound of three elements of manganese, chromium and an element M is a solid solution compound). 7. The method according to claim 1, comprising a first step of obtaining a mixture by mixing the mixture and a second step of firing the mixture in an inert gas atmosphere. Production method of the lithium manganese composite oxide particulate composition. 8. A compound of a lithium compound, a trivalent manganese compound, a chromium compound, a compound of an element M, and a compound of an element N (two or more of the compounds of the four elements of manganese, chromium, the element M, and the element N) Wherein said compound may be a solid solution compound), and a second step of firing said mixture under an inert gas atmosphere to obtain a mixture. 7. The method for producing a lithium manganese composite oxide particulate composition according to any one of 6. 9. The lithium compound is at least one selected from the group consisting of lithium hydroxide, lithium carbonate and lithium nitrate, the trivalent manganese compound is manganese trioxide or manganese oxyhydroxide, and the solid solution compound is oxidized. The method for producing a lithium manganese composite oxide particulate composition according to claim 7 or 8, which is a product. 10. A lithium ion secondary battery comprising a positive electrode, a negative electrode and an electrolyte, wherein the lithium manganese composite oxide particulate composition according to any one of claims 1 to 6 is used as a positive electrode active material. Rechargeable battery.