KR101520634B1 - Lithium Manganese-Based Oxide of High Capacity and Lithium Secondary Battery Comprising the Same - Google Patents

Abstract

The present invention provides a cathode active material comprising a lithium manganese-based oxide, wherein the lithium manganese-based oxide has a composition represented by the following formula (1).
_{Li 1 + 3w + x M y} Mn 1-wy O 2-z Q z * Li 1 + a M 'b Mn 2-b O 4-c Q' c (1)
Wherein w, x, y, z, a, b, c, M, M ', Q and Q' are as defined in the specification.
The lithium manganese-based oxide according to the present invention contains excessive lithium, and thus can utilize the 3V region, thereby exhibiting excellent capacity and cycle characteristics.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-capacity lithium manganese-based oxide and a lithium secondary battery comprising the same. 2. Description of the Related Art Lithium manganese-

The present invention relates to a positive electrode active material containing a lithium manganese-based oxide, wherein the lithium manganese-based oxide is capable of operating in a 3 V range to exhibit a high capacity and a lithium secondary battery comprising such a lithium manganese-based oxide.

Recently, as the interest in environmental problems grows, researches on electric vehicles and hybrid electric vehicles that can replace fossil fuel-based vehicles such as gasoline vehicles and diesel vehicles, which are one of the main causes of air pollution, are being conducted. Although a nickel metal hydride secondary battery is mainly used as a power source for such electric vehicles and hybrid electric vehicles, researches using a lithium secondary battery having a high energy density and a discharge voltage, a long cycle life and a low self-discharge rate are actively conducted And is in the process of commercialization.

As a negative electrode active material of such a lithium secondary battery, a carbon material is mainly used, and the use of lithium metal, a sulfur compound and the like are also considered. In addition, lithium-containing cobalt oxide (LiCoO ₂ ) is mainly used as the positive electrode active material, and a lithium-containing manganese oxide such as LiMnO _{2 having a} layered crystal structure and LiMn ₂ O _{4 having a} spinel crystal structure and a lithium- ₂ ) is also considered.

Among the above cathode active materials, LiCoO ₂ is most widely used because it has excellent lifetime characteristics and charge / discharge efficiency, but it has a disadvantage that its structural stability is poor and its cost competitiveness is limited due to resource limitations of cobalt used as a raw material Electric vehicles and the like.

The LiNiO ₂ cathode active material exhibits a relatively low cost and high discharge capacity, but exhibits a rapid phase transition of the crystal structure in accordance with the volume change accompanying the charging / discharging cycle, and the safety is significantly lowered when exposed to air and moisture There is a problem.

In addition, lithium manganese oxides such as LiMnO ₂ and LiMn ₂ O ₄ have an advantage that they are excellent in thermal stability and low in cost, but have a small capacity, poor cycle characteristics, and poor high temperature characteristics.

Among these lithium manganese oxides, spinel-type LiMn ₂ O ₄ exhibits a relatively flat potential in the 4V region (3.7 to 4.3 V) and the 3V region (2.7 to 3.1 V), and when both the regions are used, A large capacity can be obtained. However, the spinel-based LiMn ₂ O ₄ contains only Li for the 4V region, and extra Li ions are required to utilize the 3V region. However, currently used cathodes are basically not able to supply Li ions with graphite or carbon. Therefore, despite the relatively safe and low price, only the 4V region with a capacity of 120 mAh / g or less can be utilized, and thus the spinel type LiMn ₂ O ₄ has a limitation with a high capacity material.

In addition, the amount of lithium that can be reversibly charged and discharged by consuming a large amount of lithium ions discharged from the anode through a reaction such as formation of a solid electrolyte interface layer (SEI layer) on the surface of the cathode at the time of initial charging And the actual use charge (SOC) is lowered.

For the above reasons, it has been sought to utilize the 3V region by using a material having a spinel structure containing excess lithium. However, there is a problem that lithium excess spinel having a stable structure is not easily produced.

Therefore, there is a high need for a method capable of producing a spinel-type lithium manganese oxide having a stable structure capable of exhibiting a high capacity by using all 3V / 4V regions.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art and the technical problems required from the past.

The inventors of the present application have conducted intensive research and various experiments and have confirmed that lithium manganese oxide based on a predetermined composition can exhibit excellent charge and discharge characteristics even in a 3 V range and have completed the present invention .

Accordingly, the present invention provides a positive electrode active material comprising a lithium manganese-based oxide, wherein the lithium manganese-based oxide has a composition represented by the following formula (1).

_{Li 1 + 3w + x M y} Mn 1-wy O 2-z Q z * Li 1 + a M 'b Mn 2-b O 4-c Q' c (1)

In this formula,

0? W? 0.05, 0 <x? 1, 0? Y? 0.3, 0? Z? 0.5, -0.3? A? 0.3, 0? B? 0.5,

M and M 'are independently selected from the group consisting of Al, Mg, Ni, Co, Fe, Cr, V, Ti, Cu, B, Ca, Zn, Zr, Nb, Mo, Sr, Sb, Lt; / RTI &gt;;

Q and Q 'are, independently of each other, one or more elements selected from the group consisting of N, F, S and Cl.

When the oxidation number of Q and Q 'is not -2, the values of z and c may be changed according to the oxidation number.

When a lithium source is added to the cathode of a lithium secondary battery or a lithium manganese oxide having a spinel crystal structure represented by Li ₂ Mn ₂ O ₄ is used as a cathode active material, a maximum capacity of about 260 mAh / g in the 4 V and 3 V regions Lt; / RTI &gt;

However, when a lithium source is added to the negative electrode, lithium ions desorbed from the positive electrode are hardly inserted into the negative electrode, and precipitate into crystals on the electrolyte to form a dendritic phase. In this case, internal short-circuiting may occur due to damage to the separator and contact with the anode, which may cause a problem in the safety of the lithium secondary battery.

In addition, it is difficult to synthesize a lithium manganese oxide having a stable spinel crystal structure represented by Li ₂ Mn ₂ O ₄ .

In the case of a lithium secondary battery, since lithium reacts with a part of components constituting the electrolyte to form a solid electrolyte interface (SEI) film on the surface of the cathode and is consumed in an inactive portion of the cathode during the initial charging process, Only the anode returns to the anode, resulting in a decrease in charge / discharge efficiency. That is, a portion of lithium is used to consume the irreversible portion of the cathode during the initial charge.

On the other hand, the lithium manganese-based oxide of Formula 1 of the present invention has a layered structure containing excess lithium, so that the irreversible capacity of the negative electrode can be offset in the charge and discharge process of the excess lithium. It can also be used as a lithium source for operation in the 3V region and can operate in the 3V to 4V region. As a result, the charge / discharge capacity of the secondary battery can be increased.

That is, when a material having a composition as shown in Formula 1 is used as a cathode active material, it can be used not only in a 4V region but also in a 3V region. Thus, a cathode active material having a higher capacity than a lithium manganese oxide having a general spinel crystal structure can be obtained.

In the above formula (1), in order to consume the irreversible portion of the negative electrode and to use the 3V region, the larger the amount of Li, the better. However, due to the oxidation problem, it is not preferable that the amount (x) of excess Li exceeds 0.6. For the above reason, it is preferable that 0.2? X? 0.6.

The material of Formula 1 may be in the form of a mixture or a composite. As the mixture, the layered structure and the spinel structure may be involved in charge / discharge of lithium, respectively, or the layered structure and the spinel structure may be formed of a composite. Preferably, the layered structure and the spinel structure form a composite at a level having a grain boundary.

The cathode active material may further include at least one material selected from the group consisting of a lithium metal oxide having a layered structure and a lithium-containing phosphorous having an olivine structure in addition to the lithium manganese oxide represented by the general formula (1).

The lithium metal oxide of the layered structure is not limited in its kind but preferable examples thereof include lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium cobalt-nickel oxide, lithium cobalt-manganese oxide, lithium manganese- Lithium-cobalt-nickel-manganese oxide, and materials in which these elements are substituted or doped with other elements.

The lithium-containing phosphate of the olivine structure is not limited in its kind, but a preferable example thereof is one or two or more selected from the group consisting of a lithium iron phosphate and a substance substituted or doped with the other element.

The other element may be one or two or more elements selected from the group consisting of Al, Mg, Mn, Ni, Co, Cr, V and Fe.

The material other than the lithium manganese oxide of the spinel structure is preferably contained in an amount of 50 wt% or less based on the weight of the total cathode active material.

The present invention also provides a process for producing a lithium manganese-based oxide represented by the formula (1) by reacting a lithium manganese-based oxide having a spinel crystal structure in a reducing atmosphere with a lithium compound do.

The inventors of the present application have conducted various experiments and in-depth studies to find that when a lithium manganese-based oxide having a spinel crystal structure is reacted with a lithium compound in a reducing atmosphere, the crystal grain of the lithium manganese- It is possible to synthesize a lithium manganese-based oxide such as that shown in formula (1).

In the production process of the present invention, the lithium compound may be, for example, one or more selected from the group consisting of lithium acetate, lithium hydroxide, lithium carbonate, lithium oxide and lithium nitrate, preferably lithium acetate or Lithium hydroxide.

The reaction may be carried out by one or more methods selected from the group consisting of polyhydric alcohol method, hydrothermal synthesis method, supercritical system method, and high energy milling method, preferably by polyhydric alcohol method.

The polyhydric alcohol method may include a step of adding a lithium manganese-based oxide having a spinel crystal structure and a lithium compound as a solvent into a polyhydric alcohol and refluxing in a reducing atmosphere.

In the above method, the polyhydric alcohol may be any polyhydric alcohol having two or more hydroxy groups in the carbon chain, and one or more hydrogen atoms connected to the carbon chain may be substituted with another atom, atomic group or carbon chain It can also be used. Non-limiting examples of the polyhydric alcohol may be one or more selected from the group consisting of diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, hexylene glycol, butylene glycol and glycerol. And preferably one or more selected from the group consisting of tetraethylene glycol, triethylene glycol and diethylene glycol.

The temperature of the reflux may vary depending on the type of polyhydric alcohol used, but may range from 180 to 350 ° C. The reflux causes a reaction at the vaporization temperature of the solvent, and a condenser through which the cooling water passes is provided at the upper part so that the reaction is continuously performed. Therefore, the temperature of the reaction may vary depending on the boiling point of the solvent.

However, if the temperature is too high, an unwanted reaction may occur. If the temperature is too low, the reaction time may be too long. Thus, for example, when tetraethylene glycol is used as the polyhydric alcohol, a range of 200 to 350 ° C is preferable, and a range of 220 to 330 ° C is more preferable. In the case of diethylene glycol or triethylene glycol, the temperature is preferably in the range of 180 to 310 ° C, more preferably 200 to 300 ° C.

The present invention also provides a positive electrode material mixture comprising the above-described positive electrode active material.

In addition to the positive electrode active material, the positive electrode material mixture may optionally include a conductive material, a binder, a filler, and the like.

The conductive material is usually added in an amount of 1 to 30% by weight based on the total weight of the mixture including the cathode active material. Such a conductive material is not particularly limited as long as it has electrical conductivity without causing chemical changes in the battery, for example, graphite such as natural graphite or artificial graphite; Carbon black such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, and summer black; Conductive fibers such as carbon fiber and metal fiber; Metal powders such as carbon fluoride, aluminum, and nickel powder; Conductive whiskey such as zinc oxide and potassium titanate; Conductive metal oxides such as titanium oxide; Conductive materials such as polyphenylene derivatives and the like can be used.

The binder is added to the binder in an amount of 1 to 30% by weight, based on the total weight of the mixture containing the cathode active material, as a component that assists in bonding between the active material and the conductive agent and bonding to the current collector. Examples of such binders include polyvinylidene fluoride, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene , Polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butylene rubber, fluorine rubber, and various copolymers.

The filler is optionally used as a component for suppressing expansion of the anode, and is not particularly limited as long as it is a fibrous material without causing a chemical change in the battery. Examples of the filler include olefin-based polymerizers such as polyethylene and polypropylene; Fibrous materials such as glass fibers and carbon fibers are used.

The present invention also provides a positive electrode for a secondary battery in which the positive electrode material mixture is applied on a current collector.

The positive electrode for a secondary battery can be produced, for example, by applying a slurry prepared by mixing the positive electrode mixture to a solvent such as NMP, coating the negative electrode collector, followed by drying and rolling.

The cathode current collector is generally made to have a thickness of 3 to 500 mu m. Such a positive electrode collector is not particularly limited as long as it has conductivity without causing chemical change to the battery, and may be formed on the surface of stainless steel, aluminum, nickel, titanium, sintered carbon or aluminum or stainless steel Carbon, nickel, titanium, silver, or the like may be used. The current collector may have fine irregularities on the surface thereof to increase the adhesive force of the cathode active material, and various forms such as a film, a sheet, a foil, a net, a porous body, a foam, and a nonwoven fabric are possible.

The present invention also provides a lithium secondary battery comprising the positive electrode, the negative electrode, the separator, and a non-aqueous electrolyte containing a lithium salt.

The negative electrode is prepared, for example, by coating a negative electrode mixture containing a negative electrode active material on a negative electrode collector and then drying the mixture. The negative electrode mixture may contain the above-described components as required.

The negative electrode collector is generally made to have a thickness of 3 to 500 mu m. The negative electrode current collector is not particularly limited as long as it has high conductivity without causing chemical change in the battery. Examples of the negative electrode current collector include copper, stainless steel, aluminum, nickel, titanium, sintered carbon, copper or stainless steel Surface-treated with carbon, nickel, titanium, silver or the like, aluminum-cadmium alloy, or the like can be used. In addition, like the positive electrode collector, fine unevenness can be formed on the surface to enhance the bonding force of the negative electrode active material, and it can be used in various forms such as films, sheets, foils, nets, porous bodies, foams and nonwoven fabrics.

The separation membrane is interposed between the anode and the cathode, and an insulating thin film having high ion permeability and mechanical strength is used. The pore diameter of the separator is generally 0.01 to 10 mu m and the thickness is generally 5 to 300 mu m. Such separation membranes include, for example, olefinic polymers such as polypropylene, which are chemically resistant and hydrophobic; A sheet or nonwoven fabric made of glass fiber, polyethylene or the like is used. When a solid electrolyte such as a polymer is used as an electrolyte, the solid electrolyte may also serve as a separation membrane.

The lithium salt-containing nonaqueous electrolyte solution is composed of an electrolyte solution and a lithium salt. As the electrolyte solution, a nonaqueous organic solvent, an organic solid electrolyte, and an inorganic solid electrolyte may be used.

Examples of the non-aqueous organic solvent include N-methyl-2-pyrrolidinone, propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, gamma -Butyrolactone, 1,2-dimethoxyethane, tetrahydroxyfuran, 2-methyltetrahydrofuran, dimethylsulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane , Acetonitrile, nitromethane, methyl formate, methyl acetate, triester phosphate, trimethoxymethane, dioxolane derivatives, sulfolane, methylsulfolane, 1,3-dimethyl-2-imidazolidinone, propylene carbonate Nonionic organic solvents such as tetrahydrofuran derivatives, ethers, methyl pyrophosphate, ethyl propionate and the like can be used.

Examples of the organic solid electrolyte include a polymer electrolyte such as a polyethylene derivative, a polyethylene oxide derivative, a polypropylene oxide derivative, a phosphate ester polymer, an agitation lysine, a polyester sulfide, a polyvinyl alcohol, a polyvinylidene fluoride, A polymer containing an ionic dissociation group and the like may be used.

Examples of the inorganic solid electrolyte include Li ₃ N, LiI, Li ₅ NI ₂ , Li ₃ N-LiI-LiOH, LiSiO ₄ , LiSiO ₄ -LiI-LiOH, Li ₂ SiS ₃ , Li ₄ SiO ₄ , Nitrides, halides and sulfates of Li such as Li ₄ SiO ₄ -LiI-LiOH and Li ₃ PO ₄ -Li ₂ S-SiS ₂ can be used.

The lithium salt is a material that is readily soluble in the non-aqueous electrolyte, for example, LiCl, LiBr, LiI, LiClO 4, LiBF 4, LiB 10 Cl 10, LiPF 6, LiCF 3 SO 3, LiCF 3 CO 2, LiAsF _{6, LiSbF 6, LiAlCl 4,} CH 3 SO 3 Li, CF 3 SO 3 Li, (CF 3 SO 2) 2 NLi, chloroborane lithium, lower aliphatic carboxylic acid lithium, lithium tetraphenyl borate and imide have.

For the purpose of improving the charge / discharge characteristics and the flame retardancy, the electrolytic solution is preferably mixed with an organic solvent such as pyridine, triethylphosphite, triethanolamine, cyclic ether, ethylenediamine, glyme, Benzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinones, N, N-substituted imidazolidines, ethylene glycol dialkyl ethers, ammonium salts, pyrrole, 2-methoxyethanol, . In some cases, halogen-containing solvents such as carbon tetrachloride and ethylene trifluoride may be further added to impart nonflammability. In order to improve the high-temperature storage characteristics, carbon dioxide gas may be further added. FEC (Fluoro-Ethylene carbonate, PRS (propene sultone), FEC (fluoro-ethylene carbonate), and the like.

The secondary battery according to the present invention can be used not only in a battery cell used as a power source for a small device but also as a unit cell in a middle or large battery module including a plurality of battery cells.

Preferable examples of the above medium and large-sized devices include, but are not limited to, electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric power storage systems, and the like.

As described above, the lithium manganese-based oxide of the present invention can be used as a cathode active material to compensate for lithium loss due to the initial irreversible reaction of the negative electrode and / or to exhibit excellent charge / discharge characteristics by adding additional lithium that can be utilized in the 3V range These lithium manganese based oxides can be used for the production of lithium secondary batteries having better capacity and cycle characteristics than the conventional lithium manganese oxide.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a graph showing a voltage-current profile of a lithium ion battery using a cathode mix according to Example 1; FIG.
2 is a graph showing a voltage-current profile of a lithium-ion battery using a cathode mix according to Comparative Example 1;
3 is a graph showing a voltage-current profile of a lithium ion battery using a cathode mix according to Comparative Example 2;
4 is a graph showing a voltage-current profile of a lithium pull cell using the positive electrode material mixture according to Example 1. FIG.

Hereinafter, the present invention will be described in further detail with reference to the following examples. However, the following examples are for illustrative purposes only and are not intended to limit the scope of the present invention.

&Lt; Example 1 >

18.1 g of LiMn ₂ O ₄ and 13.2 g of Li acetate were charged into tetraethylene glycol and refluxed at 260 ° C for 10 minutes to prepare Li _{1 .95} Mn _{0 .97} O ₂ * LiMn ₂ O ₄ . A cathode mixture was prepared by adding 7 wt% of Dinka black as a conductive material and 6 wt% of PVDF as a binder to 87 wt% of the thus prepared cathode active material.

&Lt; Comparative Example 1 &

A positive electrode mixture was prepared in the same manner as in Example 1, except that the mixture was added into tetraethylene glycol and refluxed at 190 占 폚 for 10 minutes.

&Lt; Comparative Example 2 &

A positive electrode material mixture was prepared in the same manner as in Example 1, except that LiMn ₂ O ₄ was used as the positive electrode active material.

<Experimental Example 1>

The positive electrode mixture prepared in Example 1 and Comparative Examples 1 and 2 was added to NMP to prepare a slurry, which was applied to a positive electrode current collector, followed by rolling and drying to prepare a positive electrode for a secondary battery. A porous lithium polyethylene separator was interposed between the positive electrode and a negative electrode based on lithium metal, and a lithium electrolyte was injected thereinto to prepare a coin type lithium secondary battery.

The voltage-current profiles of the coin-type lithium reversal paper are shown in FIGS. FIG. 1 shows a voltage-current profile of a lithium ion battery using a cathode mix according to Example 1, and FIG. 2 shows a voltage-current profile of a lithium ion battery using a cathode mixture according to Comparative Example 1. FIG. Shows a voltage-current profile of a lithium reversed-phase paper using the positive electrode mixture according to Comparative Example 2. Fig.

Referring to these figures, the inverting cells of Comparative Examples 1 and 2 exhibited a capacity of about 120 mAh / g at 4.0 V on the first charge. However, the reversed phase of Example 1 began to exhibit a capacity at 3.75 V during the first charge, indicating a capacity of 225 mAh / g. In the case of the first charge, a capacity increase of about 2 times as compared with Comparative Examples 1 and 2 was confirmed by the process in which lithium in the positive electrode was removed and entered into the negative electrode. This is evidence that lithium-excess lithium manganese oxide was formed.

<Experimental Example 2>

The positive electrode mixture prepared in Example 1 and Comparative Examples 1 and 2 was added to NMP to prepare a slurry, which was applied to a positive electrode current collector, followed by rolling and drying to prepare a positive electrode for a secondary battery. A coin-type lithium secondary battery was fabricated by interposing a porous polyethylene separator between the positive electrode and the graphite-based negative electrode, and injecting a lithium electrolyte.

The voltage-current profile of the lithium secondary battery using the positive electrode material mixture according to Example 1 is shown in Fig.

Since the discharge profile of Experimental Example 1 uses Li metal as the negative electrode, it can not be confirmed whether the flat section in the 3V range is caused by lithium-excess lithium manganese oxide or lithium negative electrode. Therefore, if the interval of the 3V region appears in the discharge profile of the full cell using graphite as the cathode, it can be confirmed that lithium-excess lithium manganese-based oxide is used as the cathode active material.

Referring to FIG. 4, the capacity of the pull cell of Example 1 begins to be expressed at 3.5 V during the first charge, and the capacity is 225 mAh / g. In addition, a period of 2.6 V to 3 V appears at the time of discharging. The region of the 3V region that is not flat is a phenomenon that the potential of the black cathode is raised at the end of the discharge.

In the charge / discharge profiles of the full cells of Comparative Examples 1 and 2, the 3V region section did not appear. This is because in the case of the half-cell, the 3V region appears by the lithium ion generated from the lithium anode. In the case of the full cell, the cathode is graphite, so no additional lithium is supplied.

Those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims (21)

1. A cathode active material comprising a lithium manganese-based oxide, wherein the lithium manganese-based oxide has a composition represented by the following Formula 1:
_{Li 1 + 3w + x M y} Mn 1-wy O 2-z Q z * Li 1 + a M 'b Mn 2-b O 4-c Q' c (1)
In this formula,
0? W? 0.05, 0 <x? 1, 0? Y? 0.3, 0? Z? 0.5, -0.3? A? 0.3, 0? B? 0.5,
M and M 'are independently selected from the group consisting of Al, Mg, Ni, Co, Fe, Cr, V, Ti, Cu, B, Ca, Zn, Zr, Nb, Mo, Sr, Sb, Lt; / RTI &gt;;
Q and Q 'are, independently of each other, one or more elements selected from the group consisting of N, F, S and Cl. The positive electrode active material according to claim 1, wherein the positive electrode active material operates in a range of 3V to 4V. The positive electrode active material according to claim 1, wherein the positive electrode active material offsets the irreversible capacity of the negative electrode. The positive electrode active material according to claim 1, wherein the positive electrode lithium manganese oxide is a mixture or a composite. 5. The cathode active material according to claim 4, wherein the composite is a complex having a grain boundary. 5. The cathode active material according to claim 4, wherein the mixture is a mixture of a layered lithium manganese oxide and a spinel structure lithium manganese oxide. 1. A method for producing a lithium manganese-based oxide represented by the following formula (1)
A process for producing a lithium manganese-based oxide characterized by reacting a lithium manganese-based oxide having a spinel crystal structure with a lithium compound in a reducing atmosphere to synthesize a lithium manganese-
_{Li 1 + 3w + x M y} Mn 1-wy O 2-z Q z * Li 1 + a M 'b Mn 2-b O 4-c Q' c (1)
In this formula,
0? W? 0.05, 0 <x? 1, 0? Y? 0.3, 0? Z? 0.5, -0.3? A? 0.3, 0? B? 0.5,
M and M 'are independently selected from the group consisting of Al, Mg, Ni, Co, Fe, Cr, V, Ti, Cu, B, Ca, Zn, Zr, Nb, Mo, Sr, Sb, Lt; / RTI &gt;;
Q and Q 'are, independently of each other, one or more elements selected from the group consisting of N, F, S and Cl. The method according to claim 7, wherein the lithium compound is at least one selected from the group consisting of lithium acetate, lithium hydroxide, lithium carbonate, lithium oxide, and lithium nitrate. The method for producing a lithium manganese based oxide according to claim 8, wherein the lithium compound is lithium acetate or lithium hydroxide. The method according to claim 7, wherein the reaction is carried out by one or more methods selected from the group consisting of polyhydric alcohol method, hydrothermal synthesis method, supercritical system method and high energy milling method. The method for producing a lithium manganese-based oxide according to claim 10, wherein the reaction is achieved by a polyhydric alcohol method. 12. The method for producing a lithium manganese-based oxide according to claim 11, wherein the polyhydric alcohol method comprises the step of refluxing a lithium manganese oxide having a spinel crystal structure and a lithium compound as a solvent in a polyhydric alcohol. 13. The method according to claim 12, wherein the polyhydric alcohol is one or two or more selected from the group consisting of diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, hexylene glycol, butylene glycol and glycerol By weight based on the total weight of the lithium manganese-based oxide. 14. The method according to claim 13, wherein the polyhydric alcohol is at least one selected from the group consisting of tetraethylene glycol, triethylene glycol and diethylene glycol. 13. The method according to claim 12, wherein the reflux is performed at a temperature of 180 to 350 &lt; 0 &gt; C. A positive electrode material mixture comprising the positive electrode active material according to any one of claims 1 to 6. A positive electrode for a secondary battery, characterized in that the positive electrode mixture according to claim 16 is applied on a current collector. A lithium secondary battery comprising a positive electrode for a secondary battery according to claim 17. A battery module comprising the lithium secondary battery according to claim 18 as a unit cell. 20. A device comprising a battery module according to claim 19 as a power source. 21. The device of claim 20, wherein the device is an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle or a system for power storage.

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