KR20110044936A - Process for the production of lithium-manganese double oxide for lithium ion batteries and lithium-manganese double oxide for lithium ion batteries made by the same, and lithium ion batteries cotaining the same - Google Patents

Abstract

PURPOSE: A process for producing lithium-manganese composite oxide for lithium ion batteries is provided to enhance packing density, to facilitate the control of particle size and tab density, and to ensure excellent energy capacity characteristic per unit volume, electrochemical characteristics and crystallinity. CONSTITUTION: A process for producing lithium-manganese composite oxide represented by Li_(1+a)[Mn_(2-b)M_b]O_(4-c)A_c of a spinel structure comprises the steps of: (i) mixing a lithium compound, manganese compound, M-containing compound and A-containing compound; (ii) dispersing the compound of step (i) in a solvent, and wet-pulverizing the compound in order to contain particles having an average particle diameter less than about 0.3 micron to prepare slurry; (iii) spray drying the slurry of step (ii); and (iv) plasticizing the spray-dried slurry.

Description

TECHNICAL FOR THE PRODUCTION OF LITHIUM-MANGANESE DOUBLE OXIDE FOR LITHIUM ION BATTERIES AND LITHIUM-MANGANESE DOUBLE OXIDE FOR LITHIUM ION BATTERIES MADE BY THE SAME, AND LITHIUM ION BATTERIES COTAINING THE SAME}

The present invention relates to a method for producing a lithium manganese composite oxide for a lithium ion battery, a lithium manganese composite oxide for a lithium ion battery manufactured by the method, and a lithium ion secondary battery comprising the same.

LiCoO ₂ is the most widely used positive electrode active material for lithium or lithium ion secondary batteries with a potential of 4 V (voltage). Compound. However, since this material is expensive and disadvantages in terms of stability, many studies on other active materials have recently been conducted. Among them, the Li _{1 + x} Mn _{2 - x} O ₄ (0≤x≤0.12) compound having a spinel structure as a lithium manganese composite oxide is excellent in safety, rich in resources, inexpensive, and due to the environmentally friendly nature of the material. It is one of the most actively studied materials in recent years.

The conventional method for synthesizing a lithium manganese composite oxide having a spinel structure is obtained by mixing a manganese compound and a lithium compound according to a chemical composition and then performing heat treatment at a high temperature. Solid State Ionics, compounds having a spinel structure 69, 59 (1994), such as the United States, and the patent the heat treatment process in the invention of 5,718,877 number to obtain a uniform spinel than chemically described, literature (RJ Gummow is LiMn ₂ O ₄ It is not limited to the stoichiometric composition of, and in Li _{1 + x} Mn _{2 - x} O ₄ , even if the value of x varies from 0 to 0.33, it forms a spinel structure. As the value of x increases, the valence of Mn approaches 4 It is said that the crystal structure is stabilized.

On the other hand, after the report that the deterioration of the electrochemical properties of the spinel structure lithium manganese composite compound is encouraged by the non-uniformity of the spinel composition, various studies have been attempted to synthesize a spinel with a more uniform chemical composition using the liquid phase method. come. However, the size of a suitable secondary particle for use as a positive electrode active material is 10 to 25 ㎛, whereas the spinel compound synthesized by the liquid phase method is mostly obtained fine particles having a particle size of less than a few micrometers (㎛). Although these fine particles have excellent electrochemical properties of each particle, they have many problems in the actual electrode manufacturing process due to poor characteristics such as particle flowability, filling density, tap density, and wettability to a solvent. There is a problem in that it is difficult to be used as the positive electrode active material of the actual battery.

However, these spinel-structured composite oxides have a lower capacity per active material and contain more voids in the secondary particles than lithium cobalt composite oxides (referred to as Li-Co composite oxides). The active material mass mixed in the battery whose size is limited becomes small. As a result, there is a problem that the electric capacity per unit cell is small.

As a measure for improvement, recently, a mixture of a manganese compound and a lithium compound is pressed under a pressure of 500 kg / cm < 2 > There is a proposal to obtain a Li-Mn composite oxide of 1.7 g / ml or more (US Pat. No. 5805646, Japanese Patent Laid-Open No. 9 (1997) -86933). However, the specific tap density disclosed was only 1.9 g / ml, which was not satisfactory. In addition, the publication discloses an average particle diameter of secondary particles in which primary particles of a Li-Mn-based composite oxide are aggregated. However, secondary particles may be formed by using interaction between primary particles. Even if it improves, in the step of coating (electrode paste) the coating material at the time of the electrode material combination process, the cohesion disappears and it is not an intrinsic improvement measure.

Moreover, as a manufacturing method of the Li-Mn type | system | group composite oxide which has a spinel structure, the method of manufacturing by baking a mixture of manganese oxide and a lithium compound at high temperature (for example, at the temperature of 250 degreeC-850 degreeC) (Japan special characteristic) Korean Patent Publication No. 9 (1997) -86933) or a Li-Mn-B system in which a manganese compound and a lithium compound are mixed with an oxide of boron element, which can be substituted with manganese, and fired at high temperature to partially replace Mn with B. A method for producing a positive electrode active material of an oxide (Japanese Patent Laid-Open No. 4 (1992) -237970) is disclosed. However, when these raw materials are fired at high temperature in the air or in an oxygen gas flow, the secondary particles after crushing have a large average porosity (15% or more) and low tap density (1.9 g / ml or less). Higher capacity cannot be achieved by increasing the mass of the positive electrode active material mixed in the electrode.

Japanese Unexamined Patent Application Publication No. 4 (1992) -14752 discloses the use of a spinel-type lithium manganese oxide in which titanium oxide is mixed and sintered as a positive electrode active material, but titanium oxide is 950 ° C to 1000. If the temperature is not higher than or equal to 0 ° C, there is a problem that the tap density can be obtained only by 1.60 g / ml without reacting with lithium and manganese to form a melt and adding 10% by mass of titanium oxide.

LiMn ₂ O ₄ has excellent cycle life at room temperature, but has a problem in that capacity decreases rapidly during continuous charge and discharge at high temperatures. The valence of Mn in LiMn ₂ O ₄ is as 3.5, and Mn is present substantially in the form of Mn ^{+ 3} and Mn ^{+ 4.} At this time, when the temperature is increased, Mn ^{4 +} is stable, but Mn ^{3 +} is unstable, disproportionation reaction occurs in which Mn ^{3 +} becomes Mn ^{4 +} and Mn ^{2 +} during high temperature charge and discharge, and thus, high temperature charge and discharge It is known that the dose decreases rapidly. In addition, a battery using LiMn ₂ O ₄ has a problem in that a phenomenon in which capacity decreases rapidly within an initial 10 cycle occurs.

In addition, when the battery using the manganese-based positive electrode active material of LiMn ₂ O ₄ is continuously charged and discharged for a long time, particularly at high temperature, side reactions with the electrolyte occur on the surface of LiMn ₂ O ₄ . This is known to be due to the phenomenon that H 2 O and LiPF 6 in the electrolyte react to form HF, which is a strong acid, and that HF attacks Mn present on the surface of the manganese positive electrode active material and Mn elutes into the electrolyte. As a result of this side reaction, the manganese (Mn) constituting the LiMn ₂ O ₄ active material is dissolved in the electrolyte, and the active material is collapsed.

Precipitation of such manganese components is more severe when stored at high temperature, which leads to an increase in resistance of the battery. When a manganese-based lithium secondary battery is used as a power source for an electric vehicle, the above problems cause a serious decrease in output, which acts as a major cause of impeding the development of a high performance (high output) manganese-based lithium secondary battery.

Previous studies to prevent the deterioration of the manganese-based lithium secondary battery has a method of suppressing the dissolution of the spinel structure (dissolution) and a method using an electrolyte additive. However, it still does not completely suppress dissolution, and electrolytes deteriorate themselves due to high temperature storage, resulting in deterioration of performance.

Accordingly, there is a high need for a manganese-based lithium secondary battery capable of exhibiting excellent storage characteristics in long-term storage even at high temperatures by solving the above problems.

An object of the present invention is to solve the problems of the prior art as described above and to provide a method for producing a lithium manganese composite oxide for a lithium ion battery having a suitable particle size and tap density for use as a positive electrode active material.

In addition, an object of the present invention is to provide a lithium manganese composite oxide for a lithium ion battery prepared by the manufacturing method, and a lithium ion secondary battery comprising the same.

The object according to the present invention

i) lithium compounds, manganese compounds, M-containing compounds and A-containing compounds, where M is Al, Mg, Ni, Co, Zn, Ca, Sr, Cu, Zr, P, Fe, Ga, In, Cr, Ge, and Sn One element selected from the group consisting of: A is any one element selected from the group consisting of F, S and P);

ii) preparing a slurry by dispersing the compound of i) in a solvent and wet grinding until it contains particles having an average particle diameter of less than about 0.3 μm;

iii) spray drying the slurry of ii): and

iv) a spinel structure of Li _{1 + a} [Mn _{2 - b} M _b ] O _{4- c} A _c (where 0≤a≤0.3, 0.01 By a method for producing a lithium manganese composite oxide represented by? B? 0.2, 0? C? 0.02).

Wherein said lithium compound is _{Li 2 CO 3, LiNO 3,} LiNO 2, LiOH, LiOH and _{H 2 O, LiH, LiF,} LiCl, LiBr, LiI, CH 3 COOLi, Li 2 O, Li 2 SO 4, acetic acid Li, Lithium carbonate is preferred because it is selected from the group consisting of dicarboxylic acid Li, citric acid Li, fatty acid Li, alkyllithium, and lithium halide, and is easy to handle and inexpensive.

The manganese compounds include manganese oxides such as Mn ₂ O ₃ , MnO ₂ , Mn ₃ O ₄ , MnCO ₃ , Mn (NO ₃ ) ₂ , MnSO ₄ , manganese acetate, manganese dicarboxylic acid, manganese citrate, and manganese fatty acid. And halides such as oxyhydroxide and manganese chloride. Among these manganese compounds, MnO ₂ , Mn ₂ O ₃ , Mn ₃ O ₄ are preferable because they can be obtained at low cost as industrial raw materials without generating gases such as NO _x , SO _x , and CO ₂ during firing. . These manganese compounds may be used individually by 1 type, and may use 2 or more types together.

In the present invention, it contains one of the above M elements selected from the group consisting of Al, Mg, Ni, Co, Zn, Ca, Sr, Cu, Zr, P, Fe, Ga, In, Cr, Ge and Sn. Compounds of carbonates, nitrates, hydroxides, chlorides, and oxides may be included in the lithium manganese composite oxide. Such a compound can improve the stability of a lithium manganese complex oxide and the diffusibility of lithium ions. In the present invention, it is possible to employ aluminum as the M element, in which case the aluminum alloy compound may be selected from the group consisting of aluminum oxide, aluminum nitrate, aluminum carbonate, aluminum hydroxide, aluminum chloride.

The lithium manganese composite oxide produced by the production method of the present invention has a particle diameter of 5 to 50 µm and a tap density of 1.5 to 2.5 g / cm 2.

In the production method of the present invention, in the wet grinding step, water is used as a solvent, and wet grinding is performed at 3000 to 4000 rpm using zirconia beads. In the firing step, the spray drying body is subjected to oxygen-containing gas atmosphere. Firing at 920 ° C. to 940 ° C. for 5 to 10 hours.

The present invention also provides a spinel-based positive electrode active material for a lithium secondary battery prepared by the manufacturing method of the present invention and a lithium secondary battery comprising the same. .

Hereinafter, the present invention will be described in more detail.

In the production method of the present invention, the wet grinding and spray drying methods are used in the production of lithium manganese composite oxides, unlike the dry method.

In the manufacturing method of this invention, it is preferable to use the method of wet-pulverizing using a medium stirring grinder etc. after disperse | distributing a raw material compound to a dispersion medium. Although various organic solvents and aqueous solvents can be used as a dispersion medium used for the wet grinding of a slurry, water is preferable. The total weight ratio of the raw material compound to the weight of the entire slurry is 50% by weight or more, preferably 60% by weight or less. When the weight ratio is less than the above range, since the slurry concentration is extremely lean, the spherical particles produced by spray drying become smaller than necessary or easily break. If this weight ratio exceeds the above range, it is difficult to maintain uniformity of the slurry.

It is preferable to wet grind at 3000 to 4000 rpm so that the average particle diameter of the solids in the slurry is usually 2 m or less, especially 1 m or less, especially 0.3 m or less. If the average particle diameter of the solids in the slurry is too large, the reactivity in the firing step is lowered as well as the sphericity decreases, and the final powder packing density tends to be lowered. However, since the small particle size more than necessary leads to the increase of the cost of grinding | pulverization, the average particle diameter of a grinding | pulverization thing shall be 0.3 micrometer or less normally.

The method for producing a lithium manganese composite oxide according to the present invention can use a granulated powder obtained by dispersing a lithium compound, a manganese compound and a M-containing compound in a liquid medium, and spray-drying a slurry produced by wet grinding by a known method. .

Although air, nitrogen, etc. can be used as a gas supplied at the time of spray-drying of a slurry, Usually, air is used. It is preferable to use these by pressurizing. The particle size (D50) of the particles produced by spray drying of the lithium manganese composite oxide powder of the present invention is 5 to 30 µm, and the tap density is 1.7 to 2.5 g / cm 2.

Means for atomizing are not particularly important and are not limited to pressurizing nozzles with specified pore sizes; In fact, any known spray-drying apparatus can be used. Atomizers are generally classified into rotary disks and nozzles, which are divided into pressure nozzles and two-fluid nozzles. In addition, any means well known in the art may be used, such as a rotary atomizer, a pressure nozzle, a pneumatic nozzle, a sonic nozzle, and the like. Feed rate, feed viscosity, desired particle size of the spray-dried product, dispersion, droplet size of water-in-oil emulsion or water-in-oil microemulsion, and the like are typically factors considered in the selection of the spraying means.

The mixed powder thus obtained is then calcined. The firing conditions at this time depend on the raw material composition, but when the firing temperature is too high, the primary particles grow excessively. On the contrary, when the firing temperature is too low, the bulk density becomes small and the specific surface area becomes excessively large. The firing temperature is also different depending on the type of lithium compound or other metal compound used as the raw material, but is usually 900 ° C or higher, preferably 920 ° C or higher, and usually 1000 ° C or lower, preferably 940 ° C or lower. .

Although baking time also changes with temperature, it is 30 minutes or more normally in the above-mentioned temperature range, Preferably it is 5 hours or more, More preferably, it is 5 hours or more, and also usually 20 hours or less. If the firing time is too short, it is difficult to obtain lithium composite oxide powder having good crystallinity, and too long is not practical. If the firing time is too long and then pulverization is required or pulverization becomes difficult after that, it is preferably 20 hours or less.

The atmosphere at the time of baking can be made into oxygen-containing gas atmosphere, such as air, and inert gas atmosphere, such as nitrogen and argon, according to the composition and structure of the compound to manufacture.

Lithium manganese composite oxide prepared by the production method of the present invention is a spinel structure of Li _{1 + a} [Mn _{2 - b} M _b ] O _{4- c} A _c (where 0≤a≤0.3, 0.01≤b≤0.2, 0? C? 0.02), and not only pure lithium manganate (LiMn 2 O 4) but also a composition in which a part of Mn is substituted with the metal element M.

Al, Mg, Ni, Co, Zn, Ca, Sr, Cu, Zr, P, Fe, Ga, In, Cr, Ge, and Sn, which are selected as M, have a large oxygen bond energy and oxygen as a defect of spinel manganese oxide. It is possible to prevent deterioration of battery performance resulting from the defect and to prevent magnesium from eluting. As M, Al is especially preferable for manufacturing reasons (easiness of substitution).

In formula, b represents the extent to which Mn is substituted by M. FIG. If b is less than 0.01, the effect of improving the high temperature characteristic is not sufficient, and if b is greater than 0.2, a sufficient initial capacity is not obtained. Therefore, 0.06 ≦ b ≦ 0.3. The adjustment of b can be done by adjusting the amount of the mixture.

In the case of employing aluminum as the M element, although not particularly limited, aluminum oxide, aluminum nitrate, aluminum carbonate, aluminum hydroxide and aluminum chloride may be mentioned. Among them, aluminum oxide and aluminum chloride are preferable for reasons of easy mixing. In the case where Mg, Si, Ca, Ti, Cu, Ba, W or Pb is employed as the M element, those carbonates, nitrates, hydroxides, chlorides, oxides and the like can be used in the same manner.

The composition of a lithium manganese composite oxide can be adjusted by the addition (mixing ratio) of each compound at the time of mixing. In addition, the particle size distribution, BET specific surface area, tap density, and green compact density which are powder characteristics can be adjusted by a mixing method and an oxidation process.

In the lithium manganese composite oxide according to the present invention, the tap density is set to 1.5 g / cm 3 or more and less than 2.5 g / cm 3. The tap density is closely correlated with the specific surface area, and in general, particles having a high specific surface area have low porosity due to the presence of voids between the particles. The positive electrode material for lithium ion batteries needs to consider the balance of both. If it is less than 1.5 g / cm 3, the film density does not increase and high capacity cannot be achieved. Moreover, when it is 2.5 g / cm <3> or more, there exists a tendency for the permeability of electrolyte solution to worsen.

In addition, the present invention provides a lithium manganese composite oxide prepared according to this manufacturing method and a lithium secondary battery comprising the same. When manufacturing the positive electrode for lithium secondary batteries from the lithium manganese composite oxide for lithium secondary batteries of this invention, it forms by mixing carbonaceous conductive materials, such as acetylene black, graphite, Ketjen black, and a binder with the powder of such a composite oxide. As the binder, polyvinylidene fluoride, polytetrafluoroethylene, polyamide, carboxymethyl cellulose, acrylic resin, or the like is preferably used. The lithium-containing composite oxide powder, the conductive material and the binder of the present invention are used as a slurry or a kneaded product using a solvent or a dispersion medium. The positive electrode for lithium secondary batteries of the present invention is produced by supporting this on a positive electrode current collector such as aluminum foil or stainless steel foil by coating or the like.

In the lithium secondary battery using the lithium manganese composite oxide powder for lithium secondary batteries of the present invention for a positive electrode active material, a porous polyethylene, a film of porous polypropylene, or the like is used as the separator. Moreover, although various solvent can be used as a solvent of the electrolyte solution of a battery, carbonate ester is especially preferable. Carbonic acid ester can use both a cyclic and a chain form. As cyclic carbonate, propylene carbonate, ethylene carbonate (EC), etc. are illustrated. Examples of the chain carbonate include dimethyl carbonate, diethyl carbonate (DEC), ethyl methyl carbonate (EMC), methyl propyl carbonate and methyl isopropyl carbonate.

In a lithium secondary battery using the lithium manganese composite oxide powder of the present invention as a positive electrode active material, a material capable of occluding and releasing lithium ions is used as the negative electrode active material. Although the material which forms this negative electrode active material is not specifically limited, For example, a lithium metal, a lithium alloy, a carbon material, an oxide, a carbon compound, a silicon carbide compound, a silicon oxide compound mainly having a metal of periodic table 14, or a group 15, Titanium sulfide, a boron carbide compound, etc. are mentioned. As the carbon material, those obtained by pyrolysing organic substances under various pyrolysis conditions, artificial graphite, natural graphite, soil graphite, expanded graphite, flaky graphite, and the like can be used. As the oxide, a compound mainly composed of tin oxide can be used. Copper foil, nickel foil, etc. are used as a negative electrode electrical power collector. Such a negative electrode is preferably prepared by kneading the active material with an organic solvent to form a slurry, and applying the slurry to a metal foil current collector to obtain a slurry.

The lithium manganese composite oxide obtained according to the manufacturing method of the present invention has a large particle size, excellent crystallinity, and significantly improved manganese elution phenomena by aluminum, resulting in excellent battery characteristics at high temperatures, that is, cycles due to charge and discharge. Characteristics and capacity retention characteristics.

<Production of Anode Active Material>

Preparation of _{- [b M b Mn 2]} O 4- c A c (b = c = 0) < Example _1> Li 1 _{+ a}

Li ₂ CO ₃ and MnO ₂ as starting materials were determined so that the ratio of each starting material and ultrapure water to ultrapure water was 5: 5 according to the stoichiometry of the composition ratios of Examples 1-1 to 1-3 of Table 1 below. Input.

a b c Example 1-1 0 0 0 Example 1-2 0.05 0 0 Example 1-3 0.1 0 0

After stirring for 10 minutes at 400rpm in a stirrer to be uniformly mixed, the slurry was pulverized and dispersed at a high speed with a wet grinding device (Mincer, manufactured by Netzsch) until the particle size (D50) in the slurry became 0.3 μm or less. It was made. The wet mill used zirconia beads having a diameter of 0.65 mm and the milling time was fixed at 30 minutes. The viscosity of the slurry was 500 cps or less.

The drying and molding of the prepared slurry was carried out using a spray drying apparatus (product of AIN SYSTEM), and the input hot air temperature was 250 to 300 ° C, the exhaust hot air temperature was 100 to 150 ° C, and the spraying was performed using an atomizer wheel type. Anode active material precursor particles were prepared.

Thus dried and molded precursors were put in an alumina crucible and heated at a rate of 2 to 5 ° C. per minute, calcined at 800 to 900 ° C. for 5 to 10 hours, and then cooled at a rate of 2 to 5 ° C. At this time, the firing atmosphere was injected into the oxidizing atmosphere at a rate of 1L per minute. After firing, disintegration and coarse particles and impurities were removed using a 325mesh standard mesh.

Preparation of _{- [b M b Mn 2]} O 4- c A c (M = Al, b ≠ 0, c = 0) < Example 2> Li _{1 + a}

Li ₂ CO ₃ , MnO ₂ as starting materials In addition to Al ₂ O ₃ was prepared in the same manner as in Example 1, except that Al ₂ O ₃ was used according to the stoichiometric ratios of the composition ratios of Examples 2-1 to 2-3 of Table 2 below.

a b c Example 2-1 0.15 0.04 0 Example 2-2 0.15 0.08 0 Example 2-3 0.15 0.1 0

Comparative Example 1

Using the same starting material as in Example 1, a spinel positive electrode active material for a lithium secondary battery was manufactured according to a dry mixing method, which is a conventional method for preparing a spinel positive electrode active material for a general lithium secondary battery. That is, the raw materials were weighed in a stoichiometric ratio without using a wet grinding and spray drying apparatus, and mixed in a dry manner using a dry mixer, and then fired in the same manner as in Example 1.

Evaluation Example SEM Photo Measurement

The positive electrode active material prepared in Examples 1 and 2 and the positive electrode active material prepared in Comparative Example 1 were observed with a scanning electron microscope (Vega, Tescan).

The positive electrode active material scanning electron micrographs of Example 1-1 are shown in Figs. 1 (a) and 1 (b) , and the positive electrode active material scanning electron micrographs of Comparative Example 1 are shown in Figs . 2 (a) and 2 ( b) .

In the case of the lithium manganese composite oxide prepared by the wet grinding and spray drying method of the present invention, as shown in FIGS. 1 (a) and 1 (b) , the particles have spherical particles and the primary particles have a size of 3 to 4 μm. It can be observed that the size of the secondary particles is about 15 ~ 25㎛.

On the other hand, the comparative example manufactured by the conventional general dry mixing method has a crushed shape as shown in FIGS . 2 (a) and 2 (b) and it can be seen that the size of the primary particles is not even.

Evaluation Example XRD Peak Measurement

It was confirmed that the cathode active material prepared in Example 1-1 and Comparative Example was LiMn ₂ O ₄ as a chemical analysis, and the results of X-ray diffraction analysis are shown in FIGS. 3 (a) and 3 (b), respectively. As a result of X-ray diffraction analysis, it could be confirmed that the cathode active materials prepared in Examples and Comparative Examples had a spinel structure.

<Production of Anode and Lithium Battery>

Electrochemical evaluation was performed by constructing a lithium secondary battery using the spinel cathode active material obtained in Examples 1 to 2 and Comparative Example 1 as a material.

As the positive electrode active material, the spinel type positive electrode active material obtained in Examples 1 to 2 and Comparative Example 1, Super-P as the conductive agent, and polyvinylidene fluoride (PVdF) as the binder were 94: 3: The mixture was mixed uniformly to 3. The mixture was evenly applied to the aluminum foil with a coating loading level of 18 ml / cm ² and pressurized by 1 ton with a roll press to give a compact plate density of 2.8 g / cm ³ and 12 hours in a 100 ℃ vacuum oven. Vacuum drying to prepare a cathode for a lithium secondary battery. As an electrolyte, 1 mole of LiPF ₆ in a mixed solvent of EC / EMC = 1/3 of Techno Semichem A solution was used as an electrolyte and a lithium metal was used as a negative electrode to produce a 2016 standard halfcoin battery.

<Charge / Discharge Characteristics Evaluation of Battery>

In order to evaluate the electrochemical characteristics of the manufactured test cell, an electrochemical analyzer (TOSCAT 3100, manufactured by Toyo) was used, and cut-off was performed at a range of 4.3 to 3 V.

The results of charge and discharge characteristics of the battery using the cathode active materials of Examples 1-3, Example 2-3, and Comparative Example 1 are shown in FIGS. 4 (a), 4 (b), and 4 (c) , respectively.

Table 3 shows the initial charge and discharge results at 0.1 C of the batteries using the cathode active materials of Examples 1 to 2 and Comparative Example 1.

Initial charge capacity Initial discharge capacity Example 1-1 106.7 mAh / g 98.0 mAh / g Example 1-2 111.4 mAh / g 101.0 mAh / g Example 1-3 112.8 mAh / g 109.4 mAh / g Example 2-1 103.6 mAh / g 101.8 mAh / g Example 2-2 94.6 mAh / g 93.5 mAh / g Example 2-3 111.1 mAh / g 101.4 mAh / g Comparative Example 1 101.7 mAh / g 99.9 mAh / g

4 and Table 3, it can be seen that the initial discharge capacity of the battery using the positive electrode active material of Example 1-3 and Example 2-3 is about 10% improved than the capacity of the battery using the positive electrode active material of Comparative Example 1 Can be. In addition, as shown in Examples 1-1 to 1-3, it was shown that the electrochemical properties increased as the lithium content increased.

<High temperature dissolution characteristic evaluation>

In order to evaluate the effect of inhibiting the high temperature dissolution by doped or coated Al, the high temperature dissolution characteristics of the spinel cathode active material obtained in Example 2-3 and Comparative Example 1 were evaluated.

In the evaluation procedure, 0.5 g of each cathode active material was added to Teflon ruler, 13 ml of electrolyte solution was sealed, and stored in an oven at 60 ° C. for 1 day, 3 days, 5 days, and 7 days for aging. After the aging sample was filtered through a 0.2 ㎛ filter of the electrolyte and sealed in a new Teflon jar and then analyzed the components through the chemical analysis shown in Table 4 and FIG .

Aging Time Mn elution amount [ppm] Example 6 Comparative Example 1 1 day 0.085 0.089 3 days 0.243 0.259 5 days 0.375 0.486 7 days 0.413 0.717

Referring to Table 4 and FIG. 5, it can be seen that after 7 days, about 70% more Mn was eluted from the cathode active material of Comparative Example 1 than the cathode active material of Example 2-3.

It can be seen that the elution of Mn is remarkably suppressed when the metal Al is doped into the lithium manganese composite oxide according to the production method of the present invention.

1 shows a scanning electron micrograph of the lithium manganese composite oxide of Example 1-1.

2 shows a scanning electron micrograph of a lithium manganese composite oxide of Comparative Example 1. FIG.

3 is an XRD analysis graph of the lithium manganese composite oxide prepared in Example 1-1 and Comparative Example.

4 shows evaluation results of charge and discharge characteristics of a battery using lithium manganese composite oxides of Examples 1-3, Example 2-3, and Comparative Example 1. FIG.

5 shows the results of evaluating the high temperature elution characteristics of the lithium manganese composite oxide obtained in Example 2-3 and Comparative Example 1. FIG.

Claims (9)

i) lithium compounds, manganese compounds, M-containing compounds and A-containing compounds, where M is Al, Mg, Ni, Co, Zn, Ca, Sr, Cu, Zr, P, Fe, Ga, In, Cr, Ge, and Sn One element selected from the group consisting of: A is any one element selected from the group consisting of F, S and P); ii) preparing a slurry by dispersing the compound of i) in a solvent and wet grinding until it contains particles having an average particle diameter of less than about 0.3 μm; iii) spray drying the slurry of ii): and iv) Spinning of the spray-dried slurry of iii) Li _{1 + a} [Mn _{2 - b} M _b ] O _{4- c} A _c (where 0≤a≤0.3, 0.01 The manufacturing method of the lithium manganese complex oxide for lithium secondary batteries represented by <= b <0.2, 0 <= c <0.02). The method of claim 1, The lithium compound is _{Li 2 CO 3, LiNO 3,} LiNO 2, LiOH, LiOH and _{H 2 O, LiH, LiF,} LiCl, LiBr, LiI, CH 3 COOLi, Li 2 O, Li 2 SO 4, acetic acid Li, dicarboxylic Is selected from the group consisting of Li carboxylic acid, Li citrate, fatty acid Li, alkyllithium, and lithium halides, The manganese compounds include manganese oxides such as Mn ₂ O ₃ , MnO ₂ , Mn ₃ O ₄ , MnCO ₃ , Mn (NO ₃ ) ₂ , MnSO ₄ , manganese acetate, manganese dicarboxylic acid, manganese citrate, and manganese fatty acid. A method for producing a lithium manganese composite oxide for a lithium secondary battery which is selected from the group consisting of halides such as oxyhydroxide and manganese chloride. The method of claim 1, The M-containing compound is a carbonate, nitrate of one element selected from the group consisting of Al, Mg, Ni, Co, Zn, Ca, Sr, Cu, Zr, P, Fe, Ga, In, Cr, Ge and Sn , A hydroxide, a chloride, an oxide, a method for producing a lithium manganese composite oxide for a lithium secondary battery. The method of claim 3, M is aluminum, and the aluminum-containing compound is selected from the group consisting of aluminum oxide, aluminum nitrate, aluminum carbonate, aluminum hydroxide and aluminum chloride. The method of claim 1, The particle size of the spinel-based positive electrode active material for a lithium secondary battery is 5 to 50 ㎛, tap density is 1.5 to 2.5 g / ㎠ method for producing a lithium manganese composite oxide for a lithium secondary battery. The method of claim 1, The wet grinding is a method of manufacturing a lithium manganese composite oxide for a lithium secondary battery comprising using water as a solvent and wet grinding at 3000 to 4000 rpm using zirconia beads. The method of claim 1, In the firing step, the spray dried body is fired for 5 hours to 10 hours at 920 ℃ to 940 ℃ under an oxygen-containing gas atmosphere, the method for producing a lithium manganese composite oxide for a lithium secondary battery. A lithium manganese composite oxide for a lithium secondary battery manufactured by the method of claim 1. A lithium secondary battery comprising a lithium manganese composite oxide for a lithium secondary battery produced by the manufacturing method of claim 1.

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