JP2001328815A - Lithium-manganese composite oxide, method for producing the same and secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a (modified) lithium-manganese composite oxide suitable for a positive electrode material of a nonaqueous lithium secondary battery, and further to provide a method for producing the composite material, and the nonaqueous lithium secondary battery using the composite oxide as the positive electrode material. SOLUTION: This method for producing the (modified) lithium-manganese composite oxide comprises wet-mixing a (modified) manganese oxide obtained by heat-treating a (modified) manganese carbonate compound, with a lithium compound, drying the resultant slurry or paste, cracking the dried product, firing the cracked product at 350-600 deg.C, cooling the fired product to <=45 deg.C, cracking the cooled product, firing the cracked product at 600-800 deg.C. The (modified) lithium-manganese composite oxide can constitute the nonaqueous lithium secondary battery having an improved initial capacity and an improved capacity retention by using the composite oxide as the material for the positive electrode. The secondary battery is also provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lithium manganese-based double oxide, a method for producing the same, and a secondary battery. More specifically, the present invention uses a positive electrode material of a non-aqueous lithium secondary battery to reduce the initial capacity and capacity retention. Improved lithium manganese-based composite oxide capable of constituting a non-aqueous lithium secondary battery having improved charge / discharge cycle characteristics, a method for producing the same, and a method using such a lithium manganese-based composite oxide as a cathode material It relates to a water lithium secondary battery.

[0002]

2. Description of the Related Art As a positive electrode material of a nonaqueous lithium secondary battery, sulfides and oxides of titanium and molybdenum,
In addition, oxides of vanadium and phosphorus have been proposed, but these have not yet been put to practical use because they have poor storage stability as a battery and are expensive.

On the other hand, manganese dioxide has already been put into practical use as a positive electrode active material for non-aqueous primary batteries, and manganese dioxide is typically used in non-aqueous primary batteries.
Manganese dioxide is abundant and inexpensive in terms of resources, and is also chemically stable, so that it has excellent storage stability as a battery. However, manganese dioxide is not suitable as a positive electrode active material of a non-aqueous secondary battery because manganese dioxide has difficulty in reversibility of a secondary battery, and various manganese oxides modified therewith have been proposed.

For example, as disclosed in JP-A-63-114064, JP-A-63-187569, and JP-A-1-235158, a mixture of manganese dioxide and a lithium compound is subjected to heat treatment. Manganese oxides obtained and containing lithium in the crystal structure have been proposed.

[0005] These lithium-containing manganese oxides have different compositions and crystal structures of the lithium-containing manganese oxide produced due to the difference in heat treatment temperature during the production. For example, when the heat treatment temperature is 250 to 300 ° C. Has X
In the diffraction pattern, 2θ = 22 °, 31.7 °, 37
°, a manganese oxide having a crystal structure having peaks near 42 ° and 55 °, and a manganese oxide containing Li ₂ MnO ₃ when the temperature is 300 to 430 ° C.,
When the temperature is 800 to 900 ° C., the manganese oxide has a spinel structure. Further, when fired at a high temperature of 900 ° C. or more, high crystallinity is obtained, but LiMnO ₂
Are generated, and the charge-discharge cycle characteristics are deteriorated.

In these reforming methods, manganese dioxide and a lithium compound are reacted with each other in a solid phase, so that the modification does not reach the inside of the manganese dioxide particles.
Therefore, there is a disadvantage that deterioration is rapid in a charge / discharge cycle at a high current density. Then, for example, Japanese Patent Laid-Open No.
As disclosed in Japanese Patent No. 63, a method of immersing manganese dioxide in an aqueous solution in which a lithium compound is dissolved, evaporating it to dryness, and then heat-treating the manganese dioxide particles to advance the modification reaction to the inside of the pores of the manganese dioxide particles. Proposed.

However, the lithium-containing manganese dioxide which has been proposed so far has insufficient electrochemical activity for secondary battery applications, and is therefore constituted by using such lithium-containing manganese dioxide for the positive electrode. Non-aqueous lithium secondary batteries have insufficient initial capacity and capacity retention, and have insufficient charge / discharge cycle characteristics.

Further, JP-A-6-203834, JP-A-7-245106, JP-A-7-307155 and the like disclose lithium obtained by heat-treating a mixture of manganese dioxide or a manganese salt and a lithium compound. It has been proposed to use a double oxide with manganese as a positive electrode material of a lithium secondary battery. However, the lithium manganese double oxide obtained by any of the techniques cannot provide a secondary battery having high initial capacity and long-term capacity retention.

[0009]

Accordingly, the present invention provides a non-aqueous lithium secondary battery having improved initial capacity and capacity retention by using it as a cathode material of a non-aqueous lithium secondary battery, and having excellent charge-discharge cycle characteristics. A lithium manganese compound oxide or a modified lithium manganese compound oxide capable of forming a battery, a method for producing the same, and such a lithium manganese compound oxide or a modified lithium manganese compound oxide are used as a positive electrode material, and an excellent initial An object of the present invention is to provide a nonaqueous lithium secondary battery having a capacity and a capacity retention rate, and particularly having excellent charge / discharge cycle characteristics at high temperatures.

[0010]

Means for Solving the Problems The present inventors have conducted intensive studies in order to achieve the above-mentioned object, and have conducted various experiments. As a result, manganese oxide or Li obtained by heat-treating a manganese carbonate compound was obtained. , B, Mg, Al, V, Cr, Co,
A modified manganese oxide obtained by heat-treating a modified manganese carbonate compound containing at least one selected from the group consisting of Ni, Zn and Ga has a uniform particle size, a uniform composition, and decarboxylation by heat treatment. It has been found that the penetration of lithium into the manganese oxide or modified manganese oxide is easy due to the formation of pores in the manganese oxide, and that such manganese oxide or modified manganese oxide and the lithium compound are wet-mixed. However, the composition, crystal structure, etc. of the lithium manganese double oxide obtained by repeating the disintegration of the dried product, firing under specific conditions, and cooling to a specific temperature are not necessarily clear, but such Lithium manganese-based composite oxide obtained as a positive electrode material is used to improve the initial capacity and capacity retention of non-aqueous lithium secondary batteries. It found that can be configured, and have completed the present invention.

That is, the lithium manganese double oxide of the present invention is obtained by wet-mixing a manganese oxide obtained by heat-treating a manganese carbonate compound with a lithium compound, drying the obtained slurry or paste, and drying the dried product. Primary crushing,
The crushed material is primarily baked at 350 to 600 ° C., cooled to 45 ° C. or less, secondary crushed, and then secondary baked at 600 to 8000 ° C., which is a lithium manganese double oxide, It is characterized in that a non-aqueous lithium secondary battery having improved initial capacity and capacity retention can be formed by using it as a material.

Further, the modified lithium manganese double oxide of the present invention comprises Li, B, Mg, Al, V, Cr, Co, N
at least one selected from the group consisting of i, Zn and Ga
Wet-mixing the modified manganese oxide and lithium compound obtained by heat-treating the modified manganese carbonate compound containing seeds,
The obtained slurry or paste is dried, the dried product is subjected to primary crushing, the crushed product is primarily baked at 350 to 600 ° C., cooled to 45 ° C. or less, and subjected to secondary crushing, and
It is a modified lithium manganese double oxide obtained by secondary firing at 000 ° C., whereby a non-aqueous lithium secondary battery having an improved initial capacity and capacity retention can be constituted by using it as a cathode material. Features.

The method for producing a lithium manganese double oxide according to the present invention comprises the steps of: wet-mixing a manganese oxide obtained by heat-treating a manganese carbonate compound with a lithium compound; drying the obtained slurry or paste; Is primarily crushed, and the crushed material is primarily baked at 350 to 600 ° C.
After cooling to below ℃ and secondary crushing, 600-8000 ℃
And secondary firing.

The method for producing the modified lithium manganese double oxide of the present invention comprises the steps of Li, B, Mg, Al, V, Cr, C
o, a modified manganese oxide compound obtained by heat-treating a modified manganese carbonate compound containing at least one selected from the group consisting of Ni, Zn and Ga is wet-mixed with a lithium compound, and the obtained slurry or paste is dried. The dried product is subjected to primary crushing, the crushed product is primarily baked at 350 to 600 ° C., cooled to 45 ° C. or less, and subjected to secondary crushing,
It is characterized by secondary firing at 0 to 8000 ° C.

The non-aqueous lithium secondary battery of the present invention uses the above-mentioned lithium manganese double oxide or the above-mentioned modified lithium manganese double oxide as a positive electrode material, and uses a metal lithium, a lithium alloy, or a lithium alloy as a negative electrode material. It is characterized by using a carbon material or a metal oxide that can be released.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. LiOH, LiF, Li ₂ CO 3 as a lithium compound that can be used as a starting material in the present invention
₃ , LiNO ₃ , Li ₂ SO _{4, and the} like, but are not limited thereto.

The manganese oxide which can be used as a starting material in the present invention is obtained by heat-treating a manganese carbonate compound, and the modified manganese oxide is Li,
B, Mg, Al, V, Cr, Co, Ni, Zn and Ga
And a heat treatment of a modified manganese carbonate compound containing at least one selected from the group consisting of: These manganese oxides or modified manganese oxides can be used in combination with ordinary manganese dioxide.

The manganese carbonate compound is preferably an aqueous solution of a manganese compound, an aqueous basic carbonate solution,
It is a wet compound prepared by mixing at least one selected from the group consisting of a basic bicarbonate aqueous solution, a gas containing carbon dioxide, and an aqueous solution containing carbon dioxide.

Further, the above modified manganese carbonate compound is
Preferably, an aqueous solution of a manganese compound, at least one selected from the group consisting of an aqueous solution of a basic carbonate, an aqueous solution of a basic bicarbonate, a gas containing carbon dioxide and an aqueous solution containing carbon dioxide, and Li, B, Mg, Al,
It is a wet compound prepared by mixing an aqueous solution containing at least one selected from the group consisting of water-soluble compounds of V, Cr, Co, Ni, Zn and Ga.

As the aqueous solution of the manganese compound, aqueous solutions of various manganese compounds can be used. For example, aqueous solutions of manganese chloride, manganese nitrate, manganese sulfate, manganese borate, manganese formate, manganese citrate, manganese oxalate, manganese acetate and the like can be used. Preferably, aqueous solutions of manganese chloride, manganese nitrate, manganese sulfate, manganese oxalate, and manganese acetate can be used.

As the above-mentioned basic carbonate aqueous solution and basic bicarbonate aqueous solution, various basic carbonate and basic bicarbonate aqueous solutions can be used. Such basic carbonates include Na ₂ CO ₃ , K ₂ CO ₃ , KNaCO
₃ , (NH ₄ ) ₂ CO _{3 and the} like, and as the basic bicarbonate, NaHCO ₃ , KHCO ₃ , N
H ₄ HCO ₃ or the like can be used. Further, the gas containing carbon dioxide and the aqueous solution containing carbon dioxide are not particularly limited as long as they are gas or aqueous solution containing carbon dioxide. When a gas containing carbon dioxide (including carbon dioxide itself) is used, mixing is performed by bubbling.

The above Li, B, Mg, Al, V, Cr,
Various kinds of aqueous solutions containing at least one selected from the group consisting of water-soluble compounds of Co, Ni, Zn and Ga can be used. Li, B, Mg, Al, V, Cr, Co, N
Among the sulfates, nitrates, acetates, oxalates, carbonates, halides, hydroxides, oxides and the like of each of i, Zn and Ga, water-soluble ones can be used. For example, magnesium sulfate, magnesium nitrate, magnesium acetate,
Magnesium chloride, aluminum sulfate, aluminum nitrate, basic aluminum acetate, aluminum chloride, aluminum iodide, sodium aluminate and the like can be used.

The method for preparing the manganese carbonate compound using the above-mentioned various raw materials is not particularly limited.
In this preparation, carbonate ion and / or carbon dioxide are preferably mixed in a relative amount ratio of 1 to 2.5 mol, preferably 1.2 to 2 mol per 1 mol of the manganese compound, and The method for preparing the above-mentioned modified manganese carbonate compound is not particularly limited. For example, in this preparation, 1 to 2.5 moles, preferably 1. moles of carbonate ion and / or carbon dioxide per mole of the manganese compound. 2
~ 2 mol, Li, B, Mg, Al, V, Cr, Co, N
at least one selected from the group consisting of i, Zn and Ga
0.005 to 0.15 mol of seed, preferably 0.02 to
It is preferable to mix at a relative amount ratio of 0.09 mol.

The above-mentioned preparation is preferably selected from the group consisting of a basic carbonate aqueous solution, a basic bicarbonate aqueous solution, a gas containing carbon dioxide and an aqueous solution containing carbon dioxide in an aqueous solution of a manganese compound. At least one kind is continuously or intermittently dropped slowly (bubbling in the case of gas), or contains a basic carbonate aqueous solution, a basic bicarbonate aqueous solution, a gas containing carbon dioxide, and carbon dioxide. At least one selected from the group consisting of aqueous solutions
Seeds and Li, B, Mg, Al, V, Cr, Co, Ni,
An aqueous solution containing at least one selected from the group consisting of water-soluble compounds of Zn and Ga is continuously or intermittently gradually dropped (bubbled in the case of gas), and the reaction temperature is set to, for example, room temperature to 95%. C., preferably at 45 to 90 ° C., and the reaction is carried out with stirring at a rotation speed of, for example, 50 to 1000 rpm, preferably 100 to 700 rpm. Then the product is filtered off,
The filtrate is washed with deionized water until the pH becomes neutral, and dried to obtain a manganese carbonate compound or a modified manganese carbonate compound. The particle size of the manganese carbonate compound or the modified manganese carbonate compound can be controlled in the range of 0.1 to 50 μm by controlling the concentration of the aqueous solution, the reaction temperature, and the like.

A manganese oxide or a modified manganese oxide can be obtained by subjecting the manganese carbonate compound or the modified manganese carbonate compound obtained as described above to a heat treatment in an air stream or an oxygen stream at a temperature of 500 ° C. or less. .
Since the manganese oxide or modified manganese oxide thus obtained has pores formed by decarboxylation by heat treatment, it is easy to infiltrate lithium into the manganese oxide or modified manganese oxide in a later step. Becomes

In the present invention, a slurry or a paste is formed by mixing a lithium compound and a manganese oxide or a modified manganese oxide in a wet manner. Whether a slurry or a paste is formed during the wet mixing is a state in which the lithium compound is dissolved in the water constituting the slurry or the paste in the wet mixing, and the dissolved lithium compound is manganese oxide or Use a sufficient amount of water to be highly dispersed in the modified manganese oxide,
However, since it is preferable to use as little water as possible in consideration of the cost of subsequent drying, the amount varies depending on the amount of water used. With such a state, the lithium manganese compound oxide or the modified lithium manganese compound oxide obtained through the steps described later becomes very uniform in composition, and therefore has a high discharge capacity. In addition, the manganese oxide or modified manganese oxide used in the present invention has a large number of pores in the crystal structure as described above, and these pores greatly contribute to the penetration of lithium into the crystal. I think that the. On the other hand, if these compounds are dry-mixed, the mixing will be insufficient.
The composition of lithium manganate in the obtained lithium manganese composite oxide or modified lithium manganese composite oxide becomes uneven, and a lithium manganese composite oxide or modified lithium manganese composite oxide having a high discharge capacity cannot be obtained.

In the above wet mixing, for example, lithium hydroxide (LiOH.H ₂ O) and manganese oxide or modified manganese oxide are usually mixed at a molar ratio of Li: Mn of 0.7: 2 to 1.3: 2, preferably 1: 2
1.1: 2, water is added and mixed in a pot mill to form a slurry or paste. The amount of water to be added is, for example, 10 to 40, based on the total amount of lithium hydroxide and manganese oxide or modified manganese oxide.
%, Preferably 15 to 25% by mass. If the amount of water added is less than 10% by mass, the resulting aqueous mixture tends to have an insufficient amount of dissolved lithium hydroxide and a high viscosity, making dispersion difficult.
On the other hand, when the addition amount of water exceeds 40% by mass, it takes a relatively long time to dry the obtained water-containing mixture (the drying speed becomes slow), and solid-liquid separation that occurs during drying becomes large, Therefore, the uniform dispersion of lithium tends to be greatly hindered.

The slurry or paste thus obtained is then dried at a temperature of preferably from 70 to 180 ° C, more preferably from 130 to 160 ° C. Drying temperature is 70 ° C
If it is lower than this, the drying rate becomes slow, and the production efficiency decreases, which is not preferable. On the other hand, when the drying temperature exceeds 180 ° C., it is necessary to improve the performance of the dryer itself,
This is economically unfavorable because of the cost of equipment and equipment, and hence the cost of operation.
The contact time between Mn and Mn becomes relatively short, and Li
This is not preferred because the permeation reaction time of the solution becomes short.

The obtained dried product is then crushed. The degree of crushing is such that the average particle size of the crushed material is 0.5 to 50 μm, preferably 5 to 30 μm. If the average particle size of the pulverized product exceeds 50 μm, it is difficult to sufficiently mix uniformly. If the average particle size of the crushed material is smaller than 0.5 μm, there is a concern that excessive crushing may destroy the crystal structure of the product compound, and further increases the possibility that the worker may be at risk of inhaling the dust. I do.

The crushed product (granular material) thus obtained
At 350-600 ° C., preferably 400-5
The firing is performed at a temperature of 00C, more preferably 450 to 500C. Since the melting point of lithium hydroxide is 445 ° C., firing at a temperature of 450 to 500 ° C. in particular allows lithium ions to penetrate into the pores of the manganese oxide or the modified manganese oxide to form a uniform lithium manganate. can get.

The fired product thus obtained is temporarily
45 ° C. or less, preferably 25 ° C. or less, more preferably 2 ° C.
After cooling to 0 ° C. or lower, secondary crushing is performed. As a lower limit of the cooling temperature, 0 ° C. or more is appropriate for practical operation. By this cooling operation, a more uniform lithium manganese double oxide or modified lithium manganese double oxide can be obtained. The conditions for this secondary crushing are the same as those for crushing before primary firing.

The secondary crushed material thus obtained is then subjected to secondary firing. This secondary firing is performed at 600 to 800
° C, preferably 650-750 ° C, particularly preferably 68 ° C.
Perform at 0-720 ° C. By this secondary firing, the uniformity of the composition and the promotion of the reaction of unreacted substances can be efficiently achieved and the reaction can be completed, so that the lithium manganese composite which can be used for forming a high capacity secondary battery can be obtained. An oxide or a modified lithium manganese double oxide can be obtained.
When the secondary firing temperature is less than 600 ° C., not only the crystallinity of the lithium manganese double oxide or the modified lithium manganese double oxide becomes insufficient because the reaction is insufficient, but also
Unreacted substances remain and by-products are generated, and sufficient characteristics as a positive electrode active material cannot be achieved.

On the other hand, if the calcination temperature exceeds 800 ° C., the crystallinity of the lithium manganese double oxide or the modified lithium manganese double oxide becomes too high, so that crystal collapse due to intrusion and desorption of lithium ions tends to occur, In a secondary battery using such a lithium manganese double oxide or a modified lithium manganese double oxide as a positive electrode material, charge / discharge cycle characteristics deteriorate.

The lithium manganese double oxide or modified lithium manganese double oxide obtained as described above is used as a positive electrode material in the same manner as in the prior art to improve the initial capacity and capacity retention of a non-aqueous lithium secondary oxide. A battery can be configured. The reason why the lithium manganese composite oxide or the modified lithium manganese composite oxide of the present invention exhibits properties superior to those of the conventionally known lithium manganese composite oxide is unknown, but two pulverizations, two firings, It is considered that the composition and the crystal structure differ from those of the conventionally known lithium manganese double oxide by one cooling.

The non-aqueous lithium secondary battery of the present invention uses the above-mentioned lithium manganese double oxide or modified lithium manganese double oxide as the positive electrode material, and uses the conventionally used metal lithium or lithium alloy as the negative electrode material. Or a carbon material or metal oxide capable of inserting and extracting lithium. Of course, a separator such as a woven fabric, a glass fiber, or a porous synthetic resin film is used, but the material is not particularly limited. For example, a polypropylene or polyethylene porous film can be made thin and large in area, and is suitable in terms of film strength and film resistance.

The solvent of the non-aqueous electrolyte used in the non-aqueous lithium secondary battery of the present invention may be a commonly used solvent, for example, carbonates, chlorinated hydrocarbons, ethers, ketones, nitriles and the like. Can be used. At least one selected from the group consisting of ethylene carbonate (EC), propylene carbonate (PC), and γ-butyl lactone (GBL) that are high dielectric constant solvents, and diethyl carbonate (DEC), dimethyl carbonate (DMC), and esters that are low viscosity solvents It is preferable to select at least one kind from among the above-mentioned kinds and use a mixed solution thereof. As supporting salts, LiClO ₄ , LiI, LiPF ₆ , LiAlC
l ₄ , LiBF ₄ , CF ₃ SO ₃ Li, etc.
Use the type. The electrolyte and the supporting salt may be appropriately selected and adjusted in consideration of the environment in which the battery is used and the optimization for the battery application, but 0.8 to 1.5 M of LiPF ₆ , LiBF ₄ , L
EC + DEC, PC + using iClO ₄ as a supporting salt
It is desirable to use at least one of DMC and PC + EMC as a solvent. As the structure of the battery, various shapes such as a square shape, a paper type, a laminated type, a cylindrical type, and a coin type can be adopted. Other components include a current collector band, an insulating plate, and the like, but these are not particularly limited, and may be appropriately selected according to the shape described above.

[0037]

The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. <Example 1> An aqueous solution containing 142.3 g of ammonium bicarbonate in 1 L (1 mol / L) of an aqueous solution containing 151.1 g of manganese sulfate while maintaining the temperature of the reaction system at 50 ° C and stirring at 300 rpm. 1 L (1.8 mol /
L) and 1 L of an aqueous solution containing 8.4 g of sodium aluminate (0.06 mol / L) were simultaneously added dropwise over 1 hour to react. Five hours after the completion of the addition, the reaction was terminated and allowed to stand. Thereafter, the mixture was filtered, washed with deionized water until the pH became neutral, and dried at 150 ° C. to obtain a modified manganese carbonate compound. The resulting modified manganese carbonate compound was heat-treated at 300 ° C. for 24 hours in an oxygen stream to obtain a modified manganese oxide.

Lithium hydroxide (LiOH.H20);
The modified manganese oxide has a molar ratio of Li to Mn of 1.
1: 2, 20 of the total amount of the mixture
Deionized water in an amount corresponding to the mass% was added and mixed in a pot mill to prepare a slurry or paste. The slurry or paste was dried at 150 ° C., and the dried product was first pulverized. The average particle size of the crushed product was 10 μm. This crushed material was primarily fired at 470 ° C. for 12 hours in an air atmosphere. Next, the fired product was cooled to room temperature (20 ° C.) and then crushed so that the average particle size became 10 μm, and the crushed material was subjected to secondary firing in an air atmosphere at 700 ° C. for 12 hours.

X-ray diffraction and chemical analysis of the obtained calcined product
As a result, the composition is LiAl_0.1Mn _1.9O_FourIs a degeneration
It was confirmed that it was lithium manganate. Positive electrode active material
Using 82 parts by mass of this calcined material as the quality,
Using 10 parts by mass of polyblack as a binder.
8 parts by mass of vinylidene chloride was previously charged with N-methyl-2-pyrrolide
And dissolved in 58 parts by mass.
A paste was obtained.

This paste is applied to an aluminum rope,
A positive electrode plate was prepared by pressing and drying. For the counter electrode, use a metal lithium plate of the same size as the positive electrode,
A metal lithium reference electrode was used for positive electrode potential measurement. A test battery was prepared by using a 1: 1 mixed solvent of ethylene carbonate and diethyl carbonate in which LiPF ₆ was dissolved at a concentration of 1 mol / dm ³ as an electrolytic solution.

Example 2 Ammonium hydrogen carbonate was added to 14
Instead of 1 L of an aqueous solution containing 2.3 g, 1 L of an aqueous solution containing 190.8 g of sodium carbonate (1.8 mol /
A test battery was prepared in the same manner as in Example 1 except that L) was used. <Example 3> A test battery was prepared in the same manner as in Example 1, except that 41 L of carbon dioxide was reacted while bubbling for 1 hour instead of 1 L of an aqueous solution containing 142.3 g of ammonium hydrogencarbonate.

Example 4 Ammonium hydrogen carbonate was added to 14
In the same manner as in Example 1 except that an aqueous solution obtained by saturating carbon dioxide into 1 L of an aqueous solution containing 118.5 g of ammonium hydrogen carbonate (1.5 mol / L) was used instead of 1 L of an aqueous solution containing 2.3 g. A test battery was prepared.

Example 5 Lithium hydroxide (LiOH.
H2O) and the modified manganese oxide obtained in Example 1 were converted to Li
, And the molar ratio of Mn in the modified manganese oxide obtained in Example 1 to Mn in ordinary manganese dioxide is 1 instead of the molar ratio of Mn of 1.1: 2. .
A test battery was prepared in the same manner as in Example 1, except that the ratio was 1: 1.6: 0.4.

Example 6 Sodium aluminate was added to 8.
Instead of 1 L of an aqueous solution containing 4 g, 1 L of an aqueous solution containing 4.2 g of sodium aluminate (0.03 mol /
A test battery was prepared in the same manner as in Example 1 except that L) was used. <Example 7> Instead of 1 L of an aqueous solution containing 8.4 g of sodium aluminate, 11. alumina was used.
A test battery was prepared in the same manner as in Example 1, except that 1 L of an aqueous solution containing 2 g (0.08 mol / L) was used.

<Example 8>
Instead of 1 liter of an aqueous solution containing 4 g, 1
A test battery was prepared in the same manner as in Example 1 except that 1 L of an aqueous solution containing 1 g (0.06 mol / L) was used. Example 9 A test was performed in the same manner as in Example 1 except that 1 L of an aqueous solution containing 11 g of nickel nitrate (0.06 mol / L) was used instead of 1 L of an aqueous solution containing 8.4 g of sodium aluminate. Battery was created.

Comparative Example 1 Lithium hydroxide (LiOH.
H ₂ O) and the modified manganese oxide obtained in Example 1
blended so that the molar ratio between i and Mn is 1.1: 2,
A test battery was prepared in the same manner as in Example 1 except that the mixture was dry-mixed in a pot mill without adding deionized water, and then crushed. The crushed product was used as a positive electrode active material.

Comparative Example 2 Lithium hydroxide (LiOH.
H2O) and electrolytic manganese dioxide were blended so that the molar ratio of Li to Mn was 1.1: 2, and 20% by weight of the total amount of the blended deionized water was added, followed by wet mixing in a pot mill. Then, a test battery was prepared in the same manner as in Example 1 except that the slurry was adjusted.

Comparative Example 3 Lithium hydroxide (LiOH.
H ₂ O) and the modified manganese oxide obtained in Example 1
blended so that the molar ratio between i and Mn is 1.1: 2,
Deionized water in an amount corresponding to 20% by mass of the total amount of the blend was added and wet-mixed in a pot mill to prepare a slurry or paste. Apply this slurry or paste to 15
Dried at 0 ° C. and then crushed. The crushed material was primarily fired at 700 ° C. for 12 hours in an air atmosphere. A test battery was prepared in the same manner as in Example 1, except that this fired product was used as a positive electrode active material.

Comparative Example 4 Lithium hydroxide (LiOH.
H ₂ O) and the modified manganese oxide obtained in Example 1
blended so that the molar ratio between i and Mn is 1.1: 2,
Deionized water in an amount corresponding to 20% by mass of the total amount of the blend was added and wet-mixed in a pot mill to prepare a slurry or paste. Apply this slurry or paste to 15
Dried at 0 ° C. and then primary crushed. The average particle size of the crushed product was 10 μm. In the atmosphere,
The primary baking was performed at 470 ° C. for 12 hours, and the secondary baking was further performed at 700 ° C. for 12 hours. A test battery was prepared in the same manner as in Example 1, except that this fired product was used as a positive electrode active material.

Comparative Example 5 Lithium acetate and manganese acetate tetrahydrate were blended in a molar ratio of 1: 2.
The mixture was heated and dissolved in 200% by weight of ethylene glycol based on the total amount of the formulation, and heating was continued until the odor of acetic acid disappeared and ethylene glycol was removed to assimilate the mixture. Next, the obtained mixture is heat-treated at 400 ° C. for 3 hours, and is heated in air at 700 ° C.
, And the obtained fired product was made into a paste in the same manner as in Example 1 to prepare a test battery.

<Characteristic Test> The test batteries of Examples 1 to 9 and Comparative Examples 1 to 5 prepared as described above were subjected to a constant current of 0.5 mA / cm ^{2 at} a constant current of 0.5 mA / cm ^{2 in} an atmosphere of 60 ° C. .
The discharge characteristics were evaluated by repeating a charge / discharge cycle in which the battery was charged to 3 V and then discharged to 3.0 V. At this time, the discharge capacity in the first charge / discharge cycle was set to the initial capacity (mAh).
/ G), and the discharge capacity at the 10th charge / discharge cycle and the 50th cycle with respect to the initial capacity was determined as the capacity retention rate (%). The results are shown in Table 1.

[0052]

As shown in Table 1, in the test batteries of the present invention obtained in Examples 1 to 9, a high initial capacity and a high capacity retention were obtained under predetermined charge / discharge conditions. On the other hand, Comparative Example 1 (implemented by dry mixing), Comparative Example 2 (using electrolytic manganese dioxide as a manganese oxide), Comparative Example 3 (implemented only in the first firing at 700 ° C.), Comparative Example 4 out of the scope of the present invention (After the primary firing, the secondary firing was carried out without cooling to room temperature) and in the test batteries obtained in Comparative Example 5 (known technology), the initial capacity and the capacity retention were low, or the capacity retention was low. And the charge / discharge cycle characteristics were poor.

[0054]

The lithium manganese double oxide or modified lithium manganese double oxide of the present invention obtained by the production method of the present invention can be used as a positive electrode material of a non-aqueous lithium secondary battery to have an initial capacity and a capacity retention. A nonaqueous lithium secondary battery having improved and excellent charge / discharge cycle characteristics can be constituted. In addition, the nonaqueous lithium secondary battery of the present invention using such a lithium manganese double oxide or a modified lithium manganese double oxide as a positive electrode material has excellent initial capacity and capacity retention, particularly at high temperatures. Excellent charge / discharge cycle characteristics.

 ────────────────────────────────────────────────── ─── Continued on front page (72) Inventor Yutaka Umezu 2-18-14 Imazato, Nagaoka-shi, Kyoto F-term (reference) 4G048 AA04 AA05 AB01 AB05 AC06 AE05 5H029 AJ03 AJ05 AK03 AL02 AL06 AL12 AM03 AM04 AM05 AM07 BJ02 BJ03 BJ04 CJ02 CJ08 HJ14 5H050 AA07 AA08 BA16 BA17 CA09 CB02 CB07 CB12 EA10 EA24 FA17 GA02 GA05 GA10 GA26 HA14

Claims (8)

[Claims] A manganese oxide obtained by heat-treating a manganese carbonate compound and a lithium compound are wet-mixed, the obtained slurry or paste is dried, and the dried product is firstly pulverized. Primary firing at ~ 600 ° C,
After cooling to 45 ° C or less and secondary crushing, 600-800
A lithium-manganese double oxide obtained by secondary firing at 0 ° C., characterized in that a non-aqueous lithium secondary battery having improved initial capacity and capacity retention can be constituted by using it as a positive electrode material. Lithium manganese compound oxide. 2. Li, B, Mg, Al, V, Cr, Co,
A modified manganese oxide obtained by heat-treating a modified manganese carbonate compound containing at least one selected from the group consisting of Ni, Zn and Ga is wet-mixed with a lithium compound, and the obtained slurry or paste is dried. The dried product is subjected to primary crushing, the crushed product is primarily baked at 350 to 600 ° C., cooled to 45 ° C. or lower, and subjected to secondary crushing,
A modified lithium manganese double oxide obtained by secondary firing at ８8000 ° C., whereby a non-aqueous lithium secondary battery having improved initial capacity and capacity retention can be constituted by using it as a positive electrode material. A modified lithium manganese double oxide characterized by the following. 3. A manganese oxide compound obtained by heat-treating a manganese carbonate compound is wet-mixed with a lithium compound, the obtained slurry or paste is dried, and the dried product is firstly pulverized. Primary firing at ~ 600 ° C,
After cooling to 45 ° C or less and secondary crushing, 600-800
A method for producing a lithium manganese double oxide, which is carried out at 0 ° C. 4. The manganese carbonate compound is at least one selected from the group consisting of an aqueous solution of a manganese compound, an aqueous solution of a basic carbonate, an aqueous solution of a basic bicarbonate, a gas containing carbon dioxide and an aqueous solution containing carbon dioxide. The method for producing a lithium manganese double oxide according to claim 3, wherein the method is a wet compound obtained by mixing a seed with a seed. 5. Li, B, Mg, Al, V, Cr, Co,
A modified manganese oxide obtained by heat-treating a modified manganese carbonate compound containing at least one selected from the group consisting of Ni, Zn and Ga is wet-mixed with a lithium compound, and the obtained slurry or paste is dried. The dried product is subjected to primary crushing, the crushed product is primarily baked at 350 to 600 ° C., cooled to 45 ° C. or lower, and subjected to secondary crushing,
A method for producing a modified lithium manganese double oxide, comprising performing a secondary firing at a temperature of from 8000 ° C to 8000 ° C. 6. The modified manganese carbonate compound is at least selected from the group consisting of an aqueous solution of a manganese compound, an aqueous solution of a basic carbonate, an aqueous solution of a basic bicarbonate, a gas containing carbon dioxide and an aqueous solution containing carbon dioxide. One, Li, B, Mg, Al, V, Cr, Co, Ni, Z
6. The modified lithium manganese double oxide according to claim 5, which is a wet compound obtained by mixing an aqueous solution containing at least one selected from the group consisting of water-soluble compounds of n and Ga. Manufacturing method. 7. The lithium manganese double oxide according to claim 1 as a positive electrode material, metallic lithium as a negative electrode material,
A nonaqueous lithium secondary battery comprising a lithium alloy, a carbon material or a metal oxide capable of inserting and extracting lithium. 8. A cathode material comprising the modified lithium manganese double oxide according to claim 2 and a negative electrode material comprising lithium metal, a lithium alloy, or a carbon material or a metal oxide capable of inserting and extracting lithium. A non-aqueous lithium secondary battery characterized in that: