WO2001066468A1

WO2001066468A1 - Method for producing lithium manganese composite oxide and lithium cell using said lithium manganese composite oxide

Info

Publication number: WO2001066468A1
Application number: PCT/JP2001/001814
Authority: WO
Inventors: Tokuo Suita; Kenji Kataoka
Original assignee: Ishihara Sangyo Kaisha, Ltd.
Priority date: 2000-03-09
Filing date: 2001-03-08
Publication date: 2001-09-13
Also published as: AU4106501A

Abstract

A method for producing a lithium manganese composite oxide containing another type of metal, characterized in that it comprises providing a lithium manganese composite oxide precursor containing at least one metal element selected from the group consisting of Fe, Cr, Co, Ni, Al, Mg, Ca, Zn, V, Nb, Mo, Ti, Zr, Ga and In, and heating and burning the precursor. The method allows the production of a lithium manganese composite oxide containing another type of metal which contains the above metal with uniformity and has excellent crystallinity.

Description

Description Method for producing lithium-manganese composite oxide and lithium battery using said lithium composite oxide

The present invention provides a method for producing a lithium-manganese composite oxide containing a heterogeneous metal element, which is a compound useful for a positive electrode material of a lithium battery, and a lithium-manganese composite oxide containing a heterogeneous metal element obtained by the production method. Related to a lithium battery. Height

Lithium secondary batteries have been rapidly spreading in recent years because of their high voltage, excellent charge / discharge cycle characteristics, light weight, and small size. In particular, batteries with a high electromotive force of 4 V class are required. As such a lithium secondary battery, one using cobalt or a composite oxide of nickel and lithium as a positive electrode active material is known. However, cobalt and nickel are expensive, and future resources are depleted.渴 is considered a problem.

Lithium manganate having a composite oxide formula L i M n ₂ 0 ₄ spinel type crystal structure which you express the like of manganese and lithium, useful as a positive electrode active material of a lithium secondary battery of 4 V class In addition, since manganese as a raw material is inexpensive and abundant in resources, it is a promising alternative to lithium cobaltate and lithium nickelate.

The lithium manganate represented by the above chemical formula has a stoichiometric composition, and a lithium battery using this as a positive electrode active material has a theoretical capacity of 148 mAhZg. However, such lithium batteries as secondary batteries have poor cycle characteristics, especially at high temperatures of 50 ° C or higher, and the battery capacity decreases when charging and discharging are repeated, and the life of the positive electrode also decreases. Therefore, lithium manganate having excellent cycle characteristics is required.

Conventionally, a method of improving the cycle characteristics by mixing and firing a manganese acid compound and a lithium compound so that lithium is greater than the stoichiometric composition, or by adjusting firing conditions so that oxygen is increased. It has been known. However, manganese oxides and Since the reactivity of the titanium compound is poor, it is difficult to obtain a homogeneous composition unless prolonged firing or mechanical pulverization is repeated many times.Oxygen desorbed when fired at high temperature to increase the reactivity It becomes lithium manganate with many lattice defects. In addition, since non-uniform sintering between particles occurs in the heating and firing step, it is difficult to control the size and shape of the particles. It is also known to improve the cycling characteristics by dissolving different metal elements in lithium manganate crystals to form a lithium-manganese complex oxide. No. 68 discloses a method of mixing a manganese oxide, a lithium compound, and a compound containing a divalent or trivalent metal element as a third component, followed by heating and baking. However, this method also has a poor reactivity between the starting materials, and thus requires long-time heating and sintering at a high temperature, has problems with crystallinity and interparticle sintering, and additionally requires a sufficient amount of metal elements. The desired performance cannot be obtained because it cannot be dissolved in lithium manganate and is locally non-uniformly dissolved.

Japanese Patent Application Laid-Open No. 10-116615 discloses a method in which a transition metal compound is precipitated on lithium manganate, and then dried and dehydrated at 150 ° C. or lower. In this method, the transition metal compound can be uniformly present on the surface of the lithium manganate, but the improvement effect is insufficient because the transition metal compound is not incorporated into the lithium manganate crystals.

Disclosure of the invention

The present invention overcomes the above-mentioned problems of the prior art and provides a lithium-manganese composite oxide containing a dissimilar metal element having excellent cycle characteristics and high charge / discharge capacity suitable for a lithium battery industrially and economically. The present invention provides a method for producing the composition in an advantageous manner.

The present inventors have conducted intensive studies and found that the lithium-manganese composite oxide precursor contained a specific heterogeneous metal element having the property of being easily replaced by the manganese ion or lithium ion of the precursor. By heating and firing, it is possible to industrially and economically produce a homogeneous composition of lithium-manganese composite oxide containing a heterogeneous metal with excellent cycle characteristics, low lattice defects, and excellent crystallinity not only at room temperature but also at high temperature. It has been found that it can be manufactured advantageously.

That is, the present invention comprises Fe, Cr, Co, Ni, Al, Mg, Ca, Zn, V, Nb, Mo, Ti, Zr, Ga and In. At least one selected from the group For producing a lithium-manganese composite oxide containing a different metal element, characterized by heating and calcining a lithium-manganese composite oxide precursor containing the same metal element, and a heterogeneous metal element obtained by the production method The present invention relates to a lithium battery using a lithium-manganese composite oxide.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1 shows the charge and discharge characteristics of Sample B.

Figure 2 shows the charge and discharge characteristics of Sample J.

FIG. 3 is an X-ray diffraction chart of Sample i.

Figure 4 shows the X-ray diffraction chart of sample ii.

FIG. 5 is an X-ray diffraction chart of Sample B.

Figure 6 shows the X-ray diffraction chart of Sample J.

BEST MODE FOR CARRYING OUT THE INVENTION

In the present invention, first, from Fe, Cr, Co, Ni, Al, Mg, Ca, Zn, V, Nb, Mo, Ti, Zr, Ga and In A lithium-manganese composite oxide precursor containing at least one metal element selected from the group consisting of: The lithium / manganese composite oxide precursor referred to in the present invention is not simply a mixture of a manganese oxide and a lithium compound, but one in which lithium ion is incorporated in the crystal structure of a manganese oxide. It may be a mixture of a suitable precursor and lithium manganate. In addition, the phrase “containing the metal element” means that a metal element or a compound containing a metal element is present inside or on a surface of an inclusion such as a precursor or a manganese oxide described below.

In order to synthesize such a lithium-manganese composite oxide precursor containing a dissimilar metal element, one of manganese oxide, manganese oxide or manganese acid reacted with an acid, and a lithium compound are mixed in a medium solution such as water. To produce a lithium-manganese composite oxide precursor, and the compound containing the metal element may be applied to the surface of the precursor. Alternatively, after the compound containing the metal element is contained on the surface of the manganese-based starting material by, for example, being applied thereto, the lithium compound is reacted with the medium in a medium such as water. Further, the lithium-manganese composite oxide precursor may be reacted with a compound containing a metal element in a medium to incorporate metal ions into the precursor. At the time of synthesis, a compound containing a metal element may be allowed to react in a medium solution to incorporate metal ions into a precursor, and there is no particular limitation.

The reaction temperature of the lithium compound with at least one selected from the group consisting of manganese oxide, manganese oxide reacted with an acid, and manganic acid is preferably 60 to 100 ° C. in a medium solution. Is 70 to 100 ° C. If the reaction is difficult to proceed, use a pressure-resistant container such as an autoclave, and maintain the temperature at 100 ° C or higher, preferably 200 ° C or lower under saturated steam pressure or under pressure. May be subjected to a hydrothermal treatment at 180 ° C. or lower. It is preferable to supply an oxidizing agent such as air, oxygen, ozone, aqueous hydrogen peroxide, or peroxodisulfate, since the reaction proceeds even under normal pressure.

Examples of the lithium compound used in the present invention include lithium hydroxide, lithium nitrate, lithium carbonate, lithium hydrogen carbonate, lithium chloride, lithium sulfate, and the like. Are preferred because they are excellent.

Manganese oxide reacted with an acid, or because the manganese oxide such as H ₂ M n 0 ₄ and H ₂ M N_〇 ₃ (Aman Gansan) are easier to react with the metal element of the lithium compound or heterologous, It is preferable to use this in the present invention. Although the reason is not clear, it is presumed that manganic acid has hydrogen ion activity and is not easily exchanged with other cations. Manganese oxide that has been reacted with an acid is similar to manganese acid because part of the manganese ions in the crystal structure of the manganese oxide is replaced with hydrogen ions, and the substituted hydrogen ions are active. It is presumed that the exchangeability with other cations is high.

The acid to be reacted with the manganese oxide is not particularly limited, such as an inorganic acid such as hydrochloric acid, sulfuric acid, nitric acid, and hydrofluoric acid, and an organic acid such as acetic acid and formic acid. However, an inorganic acid is preferable because its effect is large. Alternatively, hydrochloric acid is more preferable because it can be carried out industrially advantageously. The concentration of the acid to be added is preferably in the range of 0.05 to 10N.If the acid concentration is lower than the above range, the required amount of addition increases and the slurry concentration also decreases, so it is not industrial. . In addition, a high acid concentration is not preferable because manganese oxide is easily decomposed. As the manganese oxide to be reacted with the oxide or acid, there can be used manganese oxide, manganese oxide, manganese oxide, and the like. The manganese oxide may be synthesized by oxidizing manganese, and the crystal structure of the manganese oxide is not particularly limited, such as a spinel type, a rutile type, or a scandium oxide type. If the manganese composite oxide has a crystal structure mainly composed of a spinel type, the battery characteristics are excellent as a positive electrode material. Therefore, it is preferable to use a spinel type manganese oxide. As such a manganese oxide manga, tetramanganese manganese is mentioned.

In the present invention, a manganese oxide is prepared by reacting a manganese compound with a basic compound in a medium such as water to synthesize a manganese hydroxide and then oxidizing the manganese oxide. It is particularly preferable because the size-particle size distribution is uniform. Furthermore, if the manganese oxide is used as a seed (nucleus or seed crystal, hereinafter referred to as a seed) and the manganese oxide is grown in a medium, particles having a large particle diameter can be synthesized, and the particle diameter divided by the particle It is more preferable because the shape can be easily controlled. Manganese compounds include manganese sulphate, manganese chloride, manganese nitrate, manganese acetate, manganese carbonate and the like. Can be used.

When synthesizing manganese hydroxide, manganese oxide or manganese oxide seed by the above method, or when growing particles of manganese oxide seed described below, a compound containing a metal element is allowed to react and react. When a metal element is contained in a manganese oxide and this is reacted with a lithium compound in a medium, a lithium-manganese composite acid precursor containing the metal element used in the present invention is obtained. Alternatively, a manganese oxide having a compound containing a metal element adhered to the surface is used as a seed, and particles are grown in the same manner as described above. And then reacting with a lithium compound to obtain a lithium-manganese composite oxide precursor containing a metal element. Furthermore, the manganese oxide containing a metal element obtained by the above-described method may be reacted with an acid in advance and then with the lithium compound in order to increase the reactivity with the lithium compound. The production method of growing particles of manganese oxide in a medium using the above-mentioned manganese oxide as a seed, that is, the synthesis of manganese oxide by a seed method, involves reacting a manganese compound and a basic compound in a medium. A first step of obtaining a manganese hydroxide, a second step of obtaining a manganese oxide seed by oxidizing the manganese hydroxide, and a manganese compound in the presence of the manganese oxide seed. The reaction can be carried out by a third step in which the manganese acid seed is grown while the acid is reacted while reacting with the basic compound in a medium solution. In the first step, if the manganese compound is reacted with the basic compound to partially neutralize the manganese compound, the manganese oxide seed can be greatly grown, which is advantageous. In particular, in order to obtain a manganese oxide having a large particle diameter, the concentration of manganese ions remaining in the medium after partial neutralization is adjusted to 5 to 60 (gZl), preferably 10 to 40 (g / 1). Partially neutralized.

Various methods are used to incorporate a compound containing a metal element, such as a lithium-manganese composite oxide precursor or manganese oxide, and the desired Fe, Cr, Co, and Ni. , Al, Mg, Ca, Zn, V, Nb, Mo, Ti, Zr, force to dry-mix with a compound containing at least one metal element selected from the group consisting of Ga and In, These can be dried after mixing in a medium. Alternatively, the content is suspended in a medium such as water, and the metal salt is reacted with a basic compound in the slurry to form a hardly soluble sediment on the surface of the content. It may be formed. In this method, the compound containing the metal element is deposited as a uniform layer, and not only the yield is good, but also at this stage, a part of the metal element is incorporated into the inclusion, and the reactivity in the heating and firing step is reduced. I like it because it improves.

For example, to perform the deposition treatment in an aqueous slurry, a water-soluble compound containing a metal element or an aqueous solution thereof, or a solution obtained by dissolving a poorly water-soluble compound with an acidic or basic compound is used. And the basic compound are added to the slurry and allowed to react, and a sparingly soluble precipitate such as an oxide, hydrated oxide, or hydroxide of the metal element is formed on the surface of the substance to be contained. It can be applied as a laminate. The addition order of the metal salt solution and the basic compound or the addition thereof at the same time can be appropriately selected depending on the reaction conditions.However, depending on the basic compound, the concentration of the free hydroxyl group in the slurry is set to 0.001 in advance. to 2. '0 (mole Z 1), was preferably in 0.0 1 to 1.0 (mol / ^/ 1), a reaction by adding a metal compound Is desirable. The reaction temperature is 25 to 95 ° C, preferably 25 to 75 ° C.

As the metal compound, sulfates, nitrates, acetates, carbonates, chlorides, oxides and hydroxides of these metals can be used. There is no limitation on the basic compound, and an alkali metal compound such as hydroxide or carbonate, or an ammonia compound such as ammonia, ammonium carbonate, ammonium sulfate, or ammonium nitrate may be used. The ammonium compound is not decomposed and volatilized during the calcination and does not remain. However, it is preferable to use a lithium compound such as thiium hydroxide, because it does not become an impurity even if it remains in the final product lithium-manganese composite oxide.

The lithium / manganese composite oxide precursor containing the specific metal element obtained as described above is heated and calcined to produce a lithium / manganese composite oxide containing a different metal element. In the present invention, the reactivity between the lithium-manganese composite oxide precursor and these metal elements is good, and the metal element is easily incorporated into the precursor by replacing with manganese ions or lithium ions by heating and firing. A low-temperature sintering not only provides a uniform composition, but also allows a relatively large amount of the metal element to form a solid solution in the lithium manganate crystal. The lithium-manganese composite oxide containing a different metal element after the heating and sintering may be appropriately pulverized or crushed according to the sintering or aggregation state.

The heating and sintering temperature varies depending on the composition, particle size, sintering atmosphere, etc. of the lithium / manganese composite oxide precursor containing the heterogeneous metal element. The temperature should be at least the temperature at which the manganese composite oxide changes its phase, generally at least 400 ° C, preferably at least 500 ° C, and preferably at 850 ° C or less to prevent sintering, and at least 500 ° C and 800 It is more preferable that the temperature be not higher than ° C. The firing atmosphere is not particularly limited as long as it is an oxygen-containing atmosphere such as in the air, and the oxygen partial pressure can be appropriately set.

Different metal elements containing lithium-manganese composite oxide obtained by the method of the present invention have the general formula _{_{L i 1 + x M y Mn}} 2 - x - a compound represented by _y 0 _4, x in the formula, There range of 0.3 to 1.5 is preferred composition expressed by the value of y is (1 + x) / (2 -xy), in particular or general formula L iMn ₂ 0 _4, etc. L i _4/3 Mn _{_5/3} 0 Represented by Those having a spinel type crystal structure are preferable, and may be a single phase of lithium-manganese composite oxide or a mixture of lithium-manganese composite oxide and manganese oxide.

Further, the different metal element-containing lithium-manganese composite oxide obtained by the present invention includes Fe, Cr, Co, Ni, Al, Mg, Ca, Zn, V, Nb, Mo, Ti, Zr, It contains at least one metal element selected from the group consisting of Ga and In. As described above, since the reactivity between the compound containing these metal elements and the lithium-manganese composite oxide precursor is excellent, even if the treatment amount is relatively large, most of the metal elements are crystals of lithium manganate. It is presumed that they are dissolved in solid solution, and the effect of improving cycle characteristics, especially at high temperatures, is high. Further, since the crystallinity is excellent and the composition is uniform, a lithium battery using this has excellent various battery characteristics such as initial discharge capacity. For example, even if a compound containing these metal elements is applied to a manganese oxide and then mixed with a lithium compound and heated and fired, a product having a uniform composition as in the present invention cannot be obtained. The content is represented by MZMn atomic ratio, where M is the above-mentioned metal element, and the total amount of the different metals is 0.01 to 0.4. If the content of the metal element is less than this range, the desired charge / discharge cycle characteristics cannot be obtained, and if the content is too large, the charge / discharge capacity decreases. Therefore, for use in a so-called 4 V class lithium battery having a charge / discharge potential of about 3.5 to 4.5 V, the metal element content is preferably from 0.025 to 0.15 in terms of MZMn atomic ratio. When the charge / discharge potential is in the 5 V class of about 5 V, the content of the metal element is preferably 0.1 to 0.4 in terms of MZMn atomic ratio.

Generally, the battery capacity of a lithium battery decreases when charge and discharge are repeated, because lithium ions are desorbed and imported from the positive and negative electrode active materials every time charge and discharge are performed, and the lattice crystal shrinks and expands. It is said that this is because the crystal collapse proceeds. In addition, lithium manganate usually contains trivalent and tetravalent manganese. For example, stoichiometric lithium manganate contains the same amount of trivalent and tetravalent manganese. This trivalent manganese originally has an instability called the Jan-Teller effect, and one of the causes is that the more trivalent manganese, the more unstable the crystal structure and the easier the decay. It is said to be one.

It is not always clear why these metal compounds are effective, but In a lithium-manganese composite oxide with a composition incorporating a metallic element, the lattice constant of the crystal becomes smaller, approaches the lattice constant of the crystal from which lithium has been desorbed, and the lattice volume changes due to desorption and incorporation of lithium ions. It is presumed that the width is reduced. Alternatively, it is presumed that when a dissimilar metal element as in the present invention forms a solid solution, it is replaced with trivalent manganese to reduce its content, and the Jahn-Teller effect is not reduced.

Furthermore, the lithium-manganese composite oxide containing a different metal element obtained by the present invention has a uniform particle size distribution and particle shape, has few lattice defects, has excellent crystallinity, and has a homogeneous composition. In particular, those using the manganese oxide synthesized by the seed method described above are lithium metal composite oxides containing different metal elements containing large particles having an average particle diameter of 0 :! to 50 ^ m. Lithium containing foreign metal elements with large particle size

Since the composite oxide has excellent filling properties and can be filled in a large amount into a compact or paste as a positive electrode active material, a lithium battery using this has a high energy density. In addition, since this is grown into a desired large particle at the stage of synthesizing manganese oxide, it is not necessary to sinter by heating and sintering to grow the particle. If the particle size is smaller than the above range, desired filling properties cannot be obtained, and the cycle characteristics of a lithium battery using the same are poor. If the particle size is large, various characteristics desired for the lithium battery cannot be obtained. Here, the average particle diameter is measured by a laser scattering method.

Next, the present invention is a lithium battery using the above-described lithium / manganese composite oxide containing a different metal element as a positive electrode active material. As used herein, a lithium battery refers to a primary battery using lithium metal for the negative electrode, a rechargeable secondary battery using lithium metal for the negative electrode, a carbon material, a tin compound, lithium titanate, or the like for the negative electrode. Is a rechargeable lithium ion secondary battery. The lithium-manganese composite oxide containing a heterogeneous metal element of the present invention has few lattice defects and excellent crystallinity, and contains a specific heterogeneous metal compound uniformly. When used as an active material, crystal collapse is unlikely to occur during charge / discharge, and battery characteristics are also excellent. Furthermore, if a material having a crystal structure mainly composed of a spinel is used, it can be charged or discharged in a potential region of about 2 to 3.5 V, or a voltage of about 3.5 to 4.5 V. Certain 4 V class, and 5 V class positive electrode active material of around 5 V can be obtained. Useful for things.

When the positive electrode for a lithium battery is used for a coin-type battery, the lithium-manganese composite oxide powder of the present invention may be added to a carbon-based conductive agent such as acetylene black, carbon, or graphite powder, or polytetrafluoroethylene. It can be obtained by adding, kneading, and molding a binder such as a chemical modified polyethylene resin or a polyvinylidene fluoride resin. Further, in the case of a cylindrical or prismatic battery, an organic solvent such as N-methylpyrrolidone is added to the lithium-manganese composite oxide powder of the present invention in addition to these additives, and the mixture is kneaded. Into a paste, applied to a metal current collector such as an aluminum foil, and dried.

Lithium ion is dissolved in the electrolyte of a lithium battery in a polar organic solvent that is electrochemically stable, that is, is not oxidized or reduced in a wider range than the potential range that operates as a lithium ion battery. Things can be used. As the polar organic solvent, propylene carbonate, ethylene carbonate, getyl carbonate, dimethoxetane, tetrahydrofuran, butyl lactone, or a mixture thereof can be used. As a solute serving as a lithium ion source, lithium perchlorate, lithium hexafluorophosphate, lithium tetrafluoroborate, or the like can be used. Also between the electrodes? A flexible polypropylene film / polyethylene film is arranged as a separator.

Battery types include a separator between the positive and negative electrodes in the form of pellets, pressure bonding to a sealed can with a polypropylene gasket, injection of electrolyte, and a sealed coin-type battery. The negative electrode material is coated on a metal current collector, the separator is sandwiched and wound, inserted into a battery can with a gasket, injected with an electrolyte, and sealed. There are also three-electrode batteries specifically for measuring electrochemical properties. This battery evaluates the electrochemical characteristics of each electrode by arranging a reference electrode in addition to the positive electrode and the negative electrode, and controlling the potential of other electrodes with respect to the reference electrode.

The performance of the lithium-manganese composite oxide containing dissimilar metal elements as a positive electrode material is determined by configuring a secondary battery using metallic lithium or the like for the negative electrode, and charging and discharging an appropriate voltage range with a constant current. Its capacity can be measured. Also charge and discharge By repeating, the quality of the cycle characteristics can be determined from the change in the capacity.

Example

Examples of the present invention will be described below, but the present invention is not limited to these examples.

Example 1

1. Synthesis of manganese hydroxide

8.37 (mol / 1) 1.305 (1) sodium hydroxide solution and 0.883 (1) water were charged into a stainless steel reaction vessel. While blowing nitrogen gas therein in 5 (1 / min), rapid added with stirring a solution of (88.06% containing as MnS0 ₄₎ 1. 873 kg of manganese sulfate in water 7. 500 kg The mixture was neutralized at 70 ° C. Then, it was aged at 70 for 3 hours to obtain a manganese hydroxide. The concentration of manganese ions remaining in the solution after neutralization was 30 (gXl).

2. Synthesis of manganese oxide seed

While stirring the obtained solution containing manganese hydroxide, air was blown in at 5 (1 min) and oxidized at a temperature of 70 ° C. When the pH reached 6.4, the oxidation was terminated. A manganese oxide seed was obtained.

3. Manganese oxide seed growth

Keep the above solution containing manganese oxide seed at 70 ° C,

After a 5. 618 kg (MnS_〇 88.06% containing as ₄₎ was added an aqueous solution prepared by dissolve in water 21. 28 kg, while blowing a mixed gas of air / nitrogen at 5 (1 / min) under stirring And 8.37 (mol // 1) of sodium hydroxide 9.133 (1) were added over 64 hours, neutralized and oxidized to grow manganese oxidized seeds. When the pH reached 8.0, the growth reaction was terminated, followed by filtration and washing with water to obtain manganese oxide.

4. Reaction between manganese oxide and acid

A slurry in which manganese oxide (2400 g in terms of Mn) was dispersed in water was charged into a stainless steel reaction vessel, and the temperature was raised to 60 ° C. To this slurry, 1 (mol Z1) of sulfuric acid 6.99 (1) was added with stirring over 1 hour, and then reacted for 2 hours. Then, the mixture was filtered and washed with water to obtain a manganese oxide reacted with an acid.

5. Synthesis of lithium'manganese composite oxide precursor

5.373 mol of lithium hydroxide monohydrate was added to a slurry of manganese oxide (500 g in Mn), which had been reacted with an acid, dispersed in water and dissolved. (1) Nishi was charged into a glass reaction vessel. Air was blown into the slurry at 2 (1Z minute), the temperature was raised to 90 ° C with stirring, and the reaction was allowed to proceed for 10 hours. Then, the temperature was cooled to 60 ° C, and the lithium-manganese composite oxide precursor was cooled. The resulting slurry was obtained. The slurry was separated, filtered, washed with a 0.05 (molar Z1) lithium hydroxide solution, and dried. (Sample i)

6. Inclusion of chromium compound

The temperature of the slurry 1 (1) was raised to 60 ° C while blowing nitrogen (1 UZ for 1 UZ) with stirring, and a 4.5 (mol / 1) aqueous solution of lithium hydroxide 0.273 (1) was added. Then, 0.426 (1) of a chromium chloride aqueous solution having a concentration of 50 (g / 1) in terms of Cr was added over 1 hour, and the mixture was reacted for 5 days. After the reaction, the reaction solution was cooled, filtered, and washed with a 0.05 (mol / 1) aqueous solution of lithium hydroxide to obtain a lithium-manganese composite oxide precursor containing Cr.

7. Calcination of lithium 'manganese composite oxide precursor containing different metal elements'

The Cr-containing lithium manganese composite oxide precursor was dried at 110 ° C for 12 hours and then 750 in air. For 3 hours to obtain a lithium-manganese composite oxide.

8. Disintegration of lithium-manganese composite oxide containing different metal elements

After firing, 200 g of the lithium-manganese composite oxide was ground with a small fret mill (Yoshida Seisakusho) for 5 minutes. (Sample A) [Li (Mn + Cr) = 0.525, Cr / Mn = 0.05]

Example 2

Example 1 was repeated except that the addition amount of the lithium hydroxide monohydrate in the fifth step was 5.500 mol and the addition amount of the salt solution in the sixth step was 0.639 (1). A lithium / manganese composite oxide containing a different metal element was obtained in the same manner. (Sample B) [Li / (Mn + Cr) = 0.525, Cr / Mn = 0.075] Sample ii is the Cr-containing lithium-manganese composite oxide before thermal firing.

Example 3

In the same manner as in Example 1, except that 0.457 (1) of an aqueous solution of iron sulfate having a concentration of 50 (g / 1) in terms of Fe was added instead of the aqueous solution of salted chromium in the sixth step, An element-containing lithium-manganese composite oxide was obtained. (Sample C) [L iZ (Mn + Fe) = 0.525, Fe / Mn = 0.05]

Example 4

1 · Synthesis of lithium'manganese composite oxide precursor

4.959 mol of lithium hydroxide monohydrate was added to a slurry in which manganese oxide (450 g in terms of Mn) reacted with the acid obtained in the fourth step of Example 1 was dispersed in water. Then, water was added to make 1 (1), and the mixture was charged into a glass reaction vessel. Air was blown into the slurry at 2 (1 minute), the temperature was raised to 90 ° C with stirring, and the reaction was allowed to proceed for 14 hours. Then, the temperature was cooled to 60 ° C, and the lithium-manganese composite oxide precursor was cooled. Obtained a slurry containing the body.

2. Inclusion of chromium compound

The above slurry 1 (1) was heated to 60 while stirring with nitrogen (1 / min) while blowing nitrogen at a rate of 4.5 (mol / 1) aqueous lithium hydroxide solution 0.236 (1) and water. 0.138 (1) was added, and then an aqueous solution of chromium chloride at a concentration of 50 (g / 1) in terms of Cr, 0.426 (1), was added over 1 hour, followed by a reaction for 3 hours. After the reaction, the reaction solution was cooled, filtered, and washed with a 0.05 (molar Z1) aqueous solution of lithium hydroxide to obtain a Cr-containing lithium-manganese composite oxide precursor.

3. Firing of precursors of lithium and manganese composite oxides containing different metal elements

The lithium-manganese composite oxide precursor containing Cr was heated and calcined in the same manner as in the seventh step of Example 1, and then 20 g of the sample was disintegrated in an agate mortar to contain the dissimilar metal element of the present invention. A lithium-manganese composite oxide was obtained. (Sample D) [Li /

(Mn + Cr) = 0.54, Cr / Mn = 0.05]

Example 5

In the second step, the addition amount of water was set to 0.107 (1), and an aqueous solution of iron sulfate having a concentration of 50 (g / 1) in terms of Fe was replaced with 0.458 A lithium / manganese composite oxide containing a different metal element of the present application was obtained in the same manner as in Example 4 except that (1) was used. (Sample E) [Li / (Mn + Fe) = 0.54, Fe / Mn = 0.05]

Example 6

In the first step, the addition amount of lithium hydroxide monohydrate was 5.063 mol, and in the second step, the addition amount of lithium hydroxide aqueous solution was 0.454 (1). Example 1 except that water was not added, and that an aqueous solution of iron sulfate having a concentration of 50 (g / 1) in terms of Fe was used instead of an aqueous solution of chlorinated chloride and 0.823 (1). In the same manner as in 4, a lithium / manganese composite oxide containing a dissimilar metal element of the present application was obtained. (Sample F) [L i (Mn + Fe) = 0.53, Fe / Mn = 0.09] Example 7

In the first step, the amount of addition of hydrithium hydroxide monohydrate was set to 4.671, and in the second step, the amount of addition of water was set to 0.673 (1). The amount of aqueous solution added was 0.0356 (1), and an aqueous solution of iron sulfate with a concentration of 50 (g / 1) in terms of Fe was added instead of the aqueous solution of potassium chloride. The same operation as in Example 4 was carried out except that heat was applied, to obtain a lithium-manganese composite oxide containing a different metal element. (Sample G) [Li / (Mn + Fe) = 0.535, Fe / Mn = 0.01]

Example 8

In the second step, the amount of water added was set to 0.082 (1), and an aqueous solution of cobalt sulfate having a concentration of 50 (g / 1) 0.

483 (1) In the same manner as in Example 4 except that the compound was used, a lithium / manganese composite oxide containing a different metal element of the present application was obtained. (Sample H) [L x / (Mn + Co) = 0.

54, CoZMn = 0, 05] ·. '

Example 9

In the second step, the amount of water added was set to 0.456 (1), the amount of the aqueous solution of sodium hydroxide was set to 0.145 (1), and Mg In the same manner as in Example 4 except that an aqueous solution of magnesium sulfate having a concentration of 50 (g / 1) in terms of 0.1 (99) was used, the lithium metal containing the different metal element of the present application was Manganese composite oxide was obtained. (Sample I) [L i / (Mn + Mg) = 0.54, Mg / Mn = 0.05]

Comparative Example 1

The slurry containing the lithium manganese composite oxide precursor obtained in the fifth step of Example 1 was filtered, and then washed with 0.1 (mol Z1) of lithium hydroxide solution 2 (1), Dried at 10 ° C for 12 hours. The dried product was further heated and fired in air at 750 ° C. for 3 hours, and then pulverized with a small frit mill in the same manner as in Example 1 to obtain lithium manganate. (Sample)

Comparative Example 2

After 40 g of manganese diacid, 8.72 g of lithium carbonate and 1.79 g of iron oxide were mixed well in a mortar, they were calcined at 450 ° C. for 15 hours. After cooling, the mixture was mixed in a mortar, baked at 800 for 15 hours, and then crushed in an agate mortar in the same manner as in Example 4 to obtain a lithium-manganese composite oxide containing a different metal element. (Sample K) [L i / (Mn + Fe) = 0.525, Fe / Mn = 0.05]

Rating 1

The specific surface areas of the lithium-manganese composite oxides and lithium manganates (samples A to K) containing different metal elements obtained in Examples 1 to 9 and Comparative Examples 1 and 2 were measured using a specific surface area measuring device (monosoap: (Manufactured by Asaionitas) using the BET method. Rating 2

The aqueous slurries of lithium-manganese composite oxide and lithium manganate (samples A to K) containing different metal elements obtained in Examples 1 to 9 and Comparative Examples 1 and 2 were sufficiently ultrasonically dispersed, and the laser was used. After adjusting the transmittance by light to 85 ± 1%, the average particle diameter was measured on a volume basis using a laser-diffraction, Z-scattering particle size distribution analyzer (LA-90: manufactured by HORIBA, Ltd.).

Rating 3

Lithium containing different metal elements obtained in Examples 1 to 9 and Comparative Examples 1 and 2 Manganese composite oxide and lithium manganate (Samples A to K)

(ml), and the tap density was measured by tapping 100 times. Table 1 shows the specific surface area, average particle size, and tap density of sample AK. The lithium-manganese composite oxide containing CrFeCo and Mg obtained by the present invention has powder properties equivalent to those of lithium manganate not containing a different kind of metal element. Power.

【table 1】

Rating 4

The charge / discharge characteristics of a lithium secondary battery using the lithium-containing manganese composite oxide and lithium manganate (sample AK) obtained in Example 19 and Comparative Example 12 as the positive electrode active material, and The cycle characteristics were evaluated. The battery configuration and measurement conditions will be described.

Each of the above samples, graphite powder as a conductive agent, and polytetrafluoroethylene resin as a binder were mixed at a weight ratio of 70: 24: 6, and kneaded in a mortar to form a circle having a diameter of 10 mm. It was molded into a pellet. The pellet weighed 4 Omg. A titanium metal mesh cut into a circle having a diameter of 1 Omm was overlapped on the pellet, and pressed at 14.7 MPa to obtain a positive electrode.

The positive electrode was vacuum-dried for 120 T for 4 hours, and then incorporated in a sealable coin-type evaluation cell in a glove pot having a dew point of 170 ° C or lower. The evaluation cell used was a stainless steel (SUS316) material with an outer diameter of 2 Omm and a height of 1.6 mm. The negative electrode used was 0.5 mm thick metallic lithium molded into a 14 mm diameter circular shape. As a non-aqueous electrolyte, L i PF 6 at a concentration of 1 mol Z liter Was used, and a mixed solution of ethylene carbonate and dimethyl carbonate (mixed at a volume ratio of 1: 2) was used.

The positive electrode was placed in the lower can of the cell for evaluation, a porous polypropylene film was placed as a separator on the positive electrode, and seven drops of a nonaqueous electrolyte were dropped from above on the porous polypropylene film. The negative electrode was placed on top of it, and an upper can with a gasket made of polypropylene was covered, and the outer peripheral edge was crimped and sealed. In order to adjust the thickness, a hydrophilic non-woven polypropylene nonwoven fabric was placed above and below the separator as necessary.

The coin-type evaluation cell thus prepared was set in a dedicated battery holder, and the battery characteristics were measured with a load of 5 kg applied. The charge / discharge capacity was measured at a constant current with the voltage range set from 4.3 V to 3.5 V and the charge / discharge current set at 0.84 mA (about 3 cycles / day). The value measured in the second cycle at 25 ° C was defined as the initial charge-discharge characteristics. The cycle characteristics were measured at 25 ° C. and 50 ° C., and represented by the respective capacity retention ratios {{(30th discharge capacity Z5th discharge capacity) × 100}}.

Table 2 shows the initial charge / discharge characteristics and cycle characteristics of samples A to K. Figures 1 and 2 show the charge and discharge characteristics of Samples B and J. The lithium-manganese composite oxide containing Cr, Fe, Co and Mg obtained by the present invention has an initial charge / discharge characteristic equivalent to that of conventional lithium manganate not containing a different kind of metal element, In particular, the cycle characteristics at high temperatures are excellent.

[Table 2]

Rating 5

Lithium-manganese composite acid precursor obtained in Example, Cr-containing lithium manganese composite oxide precursor before heating and calcination, Cr-containing lithium manganese composite oxide and lithium manganate (sample ii, A, B, J) were subjected to powder X-ray diffraction analysis. In addition, CuK _ai ray was used as an X-ray source. For samples A, B, and J, the surface index (hk1) = (311), (222), (400), (331), (333), (440), and (531) surface spacing d was obtained from the diffraction peak angle, and the lattice constant a was calculated as an average value using the following equations. Table 3 shows the results. Samples A and B have smaller lattice constants than Sample J, and Sample B, which has a high Cr content, has a smaller lattice constant than Sample A, which has a low Cr content. It turns out that it is forming a solid solution.

2 1/2

a = d (h "+ k one

X-ray diffraction charts of samples i, ii, B, and J are shown in Figs. Although the sample i is the diffraction pattern similar to _{_{Mn 3 0 4, 18~ 1 9}} . Separation of peaks is observed. The high angle side is a peak due to a reaction product with Li, which indicates that a precursor is generated. Sample ii has more peak intensity on the high angle side of 18 to 19 ° than sample i, and peak intensity around 32.5 ° and 44.5 ° also increases. It is presumed that the reaction has progressed at this stage. Sample A, Diffraction pattern of B, only the peak attributable to the spinel having the same pattern as L i Mn ₂ 0 ₄ is observed. Therefore, it can be seen that in Sample B, Cr in the crystal structure was uniformly dissolved to form a single phase.

[Table 3]

Industrial applicability

The present invention provides a method for preparing a lithium manganese composite oxide precursor containing Fe, Cr, Co, Ni, Al, Mg, Ca, Zn, V, Nb, Mo, Ti, Zr, Ga and I. n and at least one metallizing element selected from the group consisting of n, and by heating and calcining, a lithium-manganese composite oxide containing a heterogeneous metal element containing the above-described metal element and having excellent crystallinity. It is a manufacturing method. A lithium battery using the lithium-manganese composite oxide containing a dissimilar metal element obtained according to the present invention as a positive electrode active material has excellent cycle characteristics particularly at ordinary temperatures and high temperatures.

Claims

The scope of the claims

1. Fe, Cr, Co, Ni, Al, Mg, Ca, Zn, V, Nb, Mo,

A heterometallic element containing a lithium manganese composite oxide precursor containing at least one metal element selected from the group consisting of Ti, Zr, Ga and In Method for producing lithium-manganese composite oxide.

2. The lithium manganese composite oxide precursor containing the metal element comprises: (1) at least one selected from the group consisting of manganese oxide, manganese oxide reacted with an acid, and manganic acid; Reacting to obtain a lithium-manganese composite oxide precursor; and (2) obtaining the lithium-manganese composite oxide precursor by containing the metal element. A method for producing an element-containing lithium-manganese composite oxide.

3. The lithium manganese composite oxide precursor containing the metal element contains at least one selected from the group consisting of (1) manganese oxide, manganese oxide reacted with an acid, and manganic acid. 2. The method for producing a lithium-manganese composite oxide containing a different metal element according to claim 1, wherein the method is obtained by a step of containing an element, and (2) a step of reacting with a lithium compound.

4. In the second step according to claim 2, in the presence of the lithium-manganese composite oxide precursor, (a) Fe, Cr, Co, Ni, Al, Mg, Ca, Zn, V, (B) reacting a compound containing at least one metal element selected from the group consisting of Nb, Mo, Ti, Zr, G a and In and (b) a basic compound to obtain the gold; A method for producing a lithium-manganese composite oxide containing a dissimilar metal element, characterized by containing a group element.

5. In the first step according to claim 3, in the presence of at least one selected from the group consisting of a manganese oxide, a manganese oxide reacted with an acid, and a manganic acid,

(a) at least one metal selected from the group consisting of Fe, Cr, Co, Ni, Al, Mg, Ca, Zn, V, Nb, Mo, Ti, Zr, Ga and In Producing a lithium-manganese composite oxide containing a heterogeneous metal element, characterized in that the metal-element-containing compound is reacted with a compound containing the element and (b) a basic compound. Construction method.

6. The production of a lithium-manganese composite oxide containing a different metal element according to claim 4 or 5, wherein the metal element is contained as at least one of an oxide, a hydrated oxide, and a hydroxide. Method.

7. The method for producing a lithium-manganese composite oxide containing a different metal element according to claim 4, wherein the basic compound is a lithium compound.

8. Manganese oxide is obtained by (1) a step of reacting a manganese compound with a basic compound to obtain a manganese hydroxide, and (2) a step of acidifying a manganese hydroxide. 4. The method for producing a lithium-manganese composite oxide containing a different metal element according to claim 2 or 3.

9. Manganese oxide (1) Step of reacting manganese compound and basic compound to obtain manganese hydroxide, (2) Oxidizing manganese hydroxide to obtain manganese oxide seed (3) a step of causing a manganese compound and a basic compound to react with each other in the presence of a manganese oxide seed to cause the manganese oxide seed to grow particles of the manganese oxide seed. Item 4. The method for producing a lithium-manganese composite oxide containing a dissimilar metal element according to Item 2 or 3.

10. At least one metal element selected from the group consisting of Fe, Cr, Co, Ni, Al, Mg, Ca, Zn, V, Nb, Mo, Ti, Zr, Ga and In The production of a lithium-manganese composite oxide containing a heterogeneous metal element according to claim 1, wherein the total amount of the heterogeneous metal element is 0.01 to 0.4, expressed as an atomic ratio MZMn, where M Method.

11. The method for producing a lithium-manganese composite oxide containing a different metal element according to claim 10, wherein the composite oxide has an average particle diameter of 0.1 to 50 μιη.

12. A lithium battery, comprising using the lithium-manganese composite oxide containing a dissimilar metal element according to claim 1 as a positive electrode active material.