JP2001106534A - Multiple metallic hydroxide as raw material of active material for nonaqueous electrolyte liquid battery and lithium multiple metallic oxide for the active material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To synthesize a multiple metallic hydroxide as a raw material of an active material for a nonaqueous electrolyte liquid battery and a lithium multiple metallic oxide for the active material which have high tap density and scarcely have remaining anionic impurities. SOLUTION: Instead of solid-soluted and coprecipitating all metals to nickel hydroxide, the metals which extremely lessen the tap density and the metals having the valence of trivalence or more are applied over the surface of the nickel hydroxide without being solid-soluted and coprecipitated thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a lithium composite metal oxide for a positive electrode active material of a non-aqueous electrolyte battery and a composite metal hydroxide used as a raw material for the synthesis.

[0002]

2. Description of the Related Art In recent years, portable electronic devices have become more portable.
Cordless and miniaturization are rapidly advancing. Accordingly, there is a strong demand for batteries used in these electronic devices to be smaller and lighter, have a higher energy density, and have a longer life.

Under such circumstances, a lithium composite metal oxide exhibiting a high charge / discharge voltage, for example, LiCoO2 (Japanese Patent Laid-Open No. 63-59507), and a lithium metal oxide having a higher capacity have been developed.
iNiO2 (US Pat. No. 4,302,518) has been reported. In particular, LiNiO2 is expected to have a higher energy density than LiCoO2, but tends to cause defects in the crystal and has poor stability as an active material. In addition, the polarization at the time of charging is large, and reaches the oxidative decomposition voltage of the electrolytic solution before Li is sufficiently extracted, so that a capacity as large as expected could not be obtained. Another problem is that the thermal stability during charging is poor. In particular, the exothermic behavior resulting from the reaction between the positive electrode active material and the non-aqueous electrolyte is a major safety issue.

[0004] In order to solve such a problem, non-aqueous electrolysis using insertion and desorption of lithium ions is used by using a material in which part of Ni is replaced by another element such as Al, Mn, or Co as a positive electrode active material. Liquid secondary batteries have been proposed.

A method for producing a lithium composite metal oxide in which a part of Ni is replaced by another element such as Al, Mn, or Co is described as follows. A method of mixing and firing lithium oxide is known. However, according to this method, the dispersion state of each element is not uniform and unevenness is easily generated, and defects are easily generated in a crystal. Therefore, an active material for a non-aqueous electrolyte battery having good discharge characteristics has not been obtained.

To solve this, other elements such as Al, Mn and Co are dissolved / coprecipitated to obtain a solid solution / coprecipitated nickel hydroxide or oxide in which the mixed / dispersed state of each element is made uniform. Mixed with lithium hydroxide
A method of manufacturing by firing is proposed.

[0007]

In the case of a nickel hydroxide raw material in which other elements such as Al, Mn, and Co are dissolved / coprecipitated, the tap density of the raw material is remarkably reduced, which is caused by the lithium composite metal oxide after firing. Affects tap density of objects. In addition, in nickel hydroxide in which an element having a valence of 3 or more is dissolved / coprecipitated, anions serving as impurities such as SO 4 2− and NO 3− are added to the crystal layer to compensate for excess positive charge. Easy to be taken into. SO42- is likely to remain as an impurity even after firing on the lithium composite oxide,
The discharge characteristics are affected, and NO3- is not preferable because NOx is generated during firing.

[0008]

Means for Solving the Problems The present inventors have proposed Mg, A
As a result of intensive studies on nickel hydroxide in which other elements such as l, Mn, Fe, and Co were solid-dissolved / coprecipitated,
The magnitude of the contribution of the coprecipitation element to the decrease in tap density is A
It was found that l> Mn ≧ Fe ≧ Co> Mg.

Further, in nickel hydroxide in which other elements such as Mg, Al, Mn, Fe, and Co are dissolved / coprecipitated,
It has also been found that the magnitude of the contribution of the solid solution / coprecipitation element to the increase in the residual amount of anions is in the order of Al> Mn ≧ Fe ≧ Co ≧ Mg. This means that among Mg, Al, Mn, Fe, and Co, Mg, Mn, Fe, and Co can be dissolved / coprecipitated in a divalent state. It is considered impossible.

Therefore, in order to solve these problems, an element which significantly lowers the tap density when solid-dissolved / coprecipitated in nickel hydroxide or an element which easily takes a valence of three or more and increases the residual amount of anions is required. The present invention has been completed in which the surface of the nickel hydroxide particles is coated without performing solid solution / coprecipitation. It is considered that the state of mixing each element is better when the surface is coated than when mixed with powder. In addition, the contribution to the decrease in tap density and the increase in the residual amount of anions varies depending on the type and proportion of the elements to be blended. Appropriate selection of elements suppresses a significant decrease in tap density and an increase in the residual amount of anions.

That is, according to the present invention, Al, Ti, V are added to the surface of nickel hydroxide particles or the surface of nickel hydroxide particles in which at least one element selected from Mg, Mn, Fe, and Co is dissolved / coprecipitated. , Cr, Mn, Fe, Co, Y,
A composite metal hydroxide coated with a hydroxide or oxide of at least one element selected from Zr and Mo, which is a raw material for synthesizing a lithium composite metal oxide for a non-aqueous electrolyte battery;
And an active material lithium composite metal oxide for a non-aqueous electrolyte battery synthesized using the same as a raw material.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of a composite metal hydroxide for a non-aqueous electrolyte battery active material according to the present invention will be described. The composite metal hydroxide according to the present invention has Al, Ti on the surface of nickel hydroxide particles or on the surface of nickel hydroxide particles in which at least one element selected from Mg, Mn, Fe, and Co is dissolved / coprecipitated. , V, Cr, Mn, Fe, C
It is coated with a hydroxide or oxide of at least one element selected from o, Y, Zr, and Mo.

In the present embodiment, the method for producing a composite metal hydroxide is composed of two steps.
Spherical or oval spherical heterogeneous elements whose physical properties are controlled by controlling H and continuously supplying and collecting an aqueous solution of a metal salt, an aqueous solution of an alkali metal hydroxide, an aqueous solution of a complexing agent, and an aqueous solution of a reducing agent to the reaction tank. Solid solution / coprecipitated nickel hydroxide mother particles are obtained. Then, in the second stage, the mother particles obtained in the first stage are dispersed in water to form a slurry, and while controlling the temperature and pH, an aqueous solution of a metal salt, an aqueous solution of a complexing agent, and an aqueous solution of an alkali metal hydroxide to be coated are supplied. Then, a composite metal hydroxide in which the base particles are coated with a metal hydroxide or an oxide is obtained.

There is no particular limitation on the mixing ratio of the different elements in the different element solid solution / coprecipitated nickel hydroxide of the first stage. Ni-based, Ni-Co-based, Ni-Mn-based, Ni-C
The basic composition is an o-Mn system, and the content of Mg and Fe is preferably 0.1 to 5 mol% based on the metal content in the composite metal hydroxide.

The proportion of metal in the coating layer in the composite metal hydroxide obtained in the second step is preferably 0.1 to 30 mol%, more preferably 1 to 30 mol%, based on the metal in the composite metal hydroxide.
10 mol% is preferred.

The average particle size of the composite metal hydroxide of the present invention determined by a laser method is not particularly limited, but is in the range of 0.1 to 50 μm, preferably 5 to 20 μm.

The metal salt used in the present invention is not particularly limited as long as it is water-soluble. The inorganic salt includes sulfate, nitrate, chloride and the like, and the organic salt includes acetate, oxalic acid and the like. Salts, citrates and the like. It is preferable to use the metal salt aqueous solution at a metal content of about 0.5 to 3.5 mol / L.

Examples of the complexing agent include ammonium ion donors such as ammonium sulfate, ammonium nitrate, ammonia water, and ammonia gas; aminocarboxylic acids such as glycine, glutamic acid, and ethylenediaminetetraacetic acid, and salts thereof; oxalic acid, malic acid, and citric acid. Examples thereof include oxycarboxylic acids such as acid and salicylic acid and salts thereof, and are preferably ammonium ion donors. The method of supplying the complexing agent is not particularly limited, and the complexing agent may be supplied alone, may be mixed in advance with the aqueous metal salt solution, or may be used in combination.

When a reducing agent is used for solid solution / coprecipitation of an element having a plurality of valences other than divalent such as Co and Mn in nickel hydroxide, the reducing agent is used for solid solution / coprecipitation in a divalent state. Sulfites such as sodium sulfite,
Nitrite such as sodium nitrite; hypophosphite such as sodium hypophosphite; hydrazine;
The method of supplying the reducing agent is not particularly limited either, and the reducing agent may be supplied alone, preliminarily mixed with the aqueous metal salt solution, or may be used in combination.

Examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide and potassium hydroxide.

[0021]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, which are merely illustrative and do not limit the present invention.

Example 1 As a metal salt aqueous solution, a mixed aqueous solution of nickel sulfate and cobalt sulfate, an ammonium sulfate aqueous solution as a complexing agent, a hydrazine aqueous solution as a reducing agent, a sodium hydroxide aqueous solution as an alkali metal aqueous solution, a coated metal salt aqueous solution Was performed as follows using an aqueous solution of aluminum nitrate.

That is, a molar ratio N
i: Co = 80: 15 1.9 mol / L nickel cobalt sulfate mixed aqueous solution of 300 mol / min, 6 mol / L
L of ammonium sulfate aqueous solution at 150 mL / min, 1
A wt% hydrazine aqueous solution was simultaneously and continuously supplied at a rate of 20 mL / min. Further, a 10 mol / L aqueous sodium hydroxide solution was automatically supplied so that the pH in the reaction tank was maintained at 12.5. The temperature in the reactor was maintained at 45 ° C,
The mixture was constantly stirred by a stirrer. The produced cobalt solid solution / coprecipitated nickel hydroxide was taken out of the overflow tube by overflowing, washed with water, dehydrated and dried. Next, the cobalt solid solution / coprecipitated nickel hydroxide base particles were dispersed in water in another reaction vessel to form a slurry. Reactor temperature 3
At 0 ° C, the pH was maintained at 8 to 9 and 1 mol /
L aluminum nitrate aqueous solution was supplied at 100 mL / min, and aluminum hydroxide was coated on the surface of the cobalt solid solution / coprecipitated nickel hydroxide particles, washed with water, dehydrated, and dried.
An Al-coated composite metal hydroxide of i: Co: Al = 80: 15: 5 was obtained.

Example 2 The procedure of Example 1 was repeated, except that the aqueous solution of the raw material metal salt for obtaining the nickel hydroxide mother particles was changed to Ni: Co: Mn = 65: 20: 10. Al = 6
An Al-coated composite metal hydroxide of 5: 20: 10: 5 was obtained.

Example 3 Ni: Co: Mg = 78: 15: 2
In the same manner as in Example 1 except that the coated metal salt aqueous solution was changed to a 1 mol / L aqueous solution of iron sulfate, Ni: Co: M
g: Fe = 78: 15: 2: 5 Fe-coated composite metal hydroxide was obtained.

Example 4 The raw material metal salt aqueous solution was 1.9 mol / L nickel sulfate alone, and the same procedure as in Example 1 was carried out without supplying the reducing agent aqueous solution. An Al-coated composite metal hydroxide was obtained.

COMPARATIVE EXAMPLE 1 A raw material metal salt aqueous solution was prepared by using Ni: Co: Al = 80: 15: 5.
, Nickel sulfate, cobalt sulfate, and aluminum nitrate were mixed at a ratio of 2 to make a raw material liquid having a metal content of 2 mol / L.
00mL / min, 1% hydrazine aqueous solution 20mL / m
in and supplied continuously at the same time. A 10 mol / L aqueous sodium hydroxide solution was automatically supplied so that the pH in the reaction vessel was maintained at 10.3. The temperature in the reaction vessel was maintained at 45 ° C., and was constantly stirred with a stirrer. The obtained Co, Al solid solution / coprecipitated nickel hydroxide is taken out by overflowing, washed with water,
After dehydration and drying, a total solid solution / coprecipitated hydroxide of Ni: Co: Al = 80: 15: 5 was obtained.

Comparative Example 2 Ni: Co: Mn: Al = 65: 2
The ratio was set to 0: 10: 5, and the rest was carried out in the same manner as in Comparative Example 1 to obtain an all solid solution / coprecipitated hydroxide.

COMPARATIVE EXAMPLE 3 Ni: Co: Mg: Fe = 78: 1
5: 2: 5, 300 mL / min, 6 mol / min
L-ammonium sulfate aqueous solution at 150 mL / min and 1% hydrazine aqueous solution at 20 mL / min were simultaneously and continuously supplied. A 10 mol / L aqueous sodium hydroxide solution was automatically supplied so that the pH in the reaction vessel was maintained at 12.5. The rest was carried out in the same manner as in Comparative Example 1 to obtain a total solid solution / coprecipitated hydroxide.

Comparative Example 4 The raw metal salt aqueous solution was set to Ni: Al = 75: 25, the reducing agent aqueous solution was not supplied, and the rest was carried out in the same manner as in Comparative Example 1 to obtain a total solid solution / coprecipitated hydroxide. Was.

The average particle diameter, tap density, and total metal solid solution / coprecipitated hydroxide of the composite metal hydroxide and a part of the metal obtained on Examples 1 to 4 and Comparative Examples 1 to 4 were coated on the surface. Table 1 shows the remaining amount of anions. The average particle size is a volume-based average particle size obtained by a laser method. The tap density was set to 40 cm3 in a container filled with powder,
It was determined by dividing the weight of the filled powder by the volume of the powder after tapping 200 times with a mm stroke. In addition, SO42 + was determined by barium salt weight method, and NO3- was determined by ion chromatography method.

[0032]

[Table 1]

The composite metal hydroxide and the all-metal solid solution / coprecipitated hydroxide obtained in Examples 1 to 4 and Comparative Examples 1 to 4 having a part of the metal coated on the surface thereof were mixed with lithium hydroxide monohydrate. Mixing (Li: metal content = 1: 1.03) and firing in an oxygen stream (preheating at 650 ° C. for 5 hours and then firing at 750 ° C. for 10 hours) were performed to obtain a lithium composite metal oxide. Characteristic X-ray element distribution analysis on the particle cross section of lithium composite metal oxide synthesized from partially element-coated composite metal hydroxide changed the element distribution state to that synthesized from all metal solid solution / coprecipitated hydroxide raw material I was able to confirm that there was no such thing. Table 2 shows the average particle size, tap density, and remaining amount of anions of these lithium composite oxides.

[Table 2]

The lithium composite metal oxides shown in Table 2 were evaluated for charge and discharge using a coin cell. The negative electrode was made of metal Li, and the electrolyte was a mixture of PC and DME of the same volume,
What dissolved LiClO4 so that it might become mol / L was used. Table 3 shows the obtained discharge capacities.

[0035]

[Table 3]

From the above results, the composite metal hydroxide according to the present invention, whose surface is coated without partially dissolving / coprecipitating some of the constituent elements, is a solid solution / coprecipitated water which dissolves / coprecipitates all the constituent elements. It is a raw material for synthesizing an active material lithium composite metal oxide for a non-aqueous electrolyte battery, which is characterized by having a higher tap density and a smaller amount of residual anions than oxides. In addition, the lithium composite metal oxide synthesized using this as a raw material is compared with a lithium composite metal oxide synthesized using a solid solution / coprecipitated hydroxide, which dissolves / coprecipitates all the constituent elements, as a raw material. Thus, the active material for a non-aqueous electrolyte battery has a feature that the tap density is large, the amount of remaining anions is small, and the discharge capacity is excellent.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Mamoru Shimakawa 5-50, Sunahawa-cho, 45, Shirakata-cho, Fukui City, Fukui Prefecture Inside Tanaka Chemical Research Institute Co., Ltd. Town No. 45, Sunahari 5-10 Co., Ltd. Tanaka Chemical Laboratory F-term (reference) 4G048 AA02 AA03 AA04 AA05 AB02 AB04 AC06 AD04 AE05 AE08 5H003 AA01 BB05 BC01 BC05

Claims (3)

[Claims] 1. A metal hydroxide used as a raw material for synthesizing a lithium composite metal oxide, wherein at least one element selected from the group consisting of nickel hydroxide particles, and Mg, Mn, Fe, and Co is dissolved. Al, Ti, V, Cr, Mn, Fe, Co,
A raw material composite metal hydroxide for a non-aqueous electrolyte battery active material, which is coated with a hydroxide or oxide of at least one element selected from Y, Zr, and Mo. 2. The composite metal hydroxide for a non-aqueous electrolyte battery active material according to claim 1, wherein the composite metal hydroxide is spherical or elliptical spherical. 3. An active material lithium composite metal oxide for a non-aqueous electrolyte battery synthesized using the raw material composite metal hydroxide for a non-aqueous electrolyte battery according to claim 1 or 2 as a raw material.