KR101693711B1 - Preparation method of lithium titanium oxide particles coated with carbon and nitrogen, electrode active material and lithium secondary batteries - Google Patents

Abstract

The present invention relates to a method for preparing lithium titanium oxide, which comprises mixing lithium titanium oxide and an aliphatic amine and refluxing at 80 to 120 캜 to coat an aliphatic amine on the surface of lithium titanium oxide; Centrifuging the mixture to obtain a solid fraction; Drying said solid matter; And carbonizing the dried solid material to prepare a lithium titanium oxide-carbon-nitrogen composite material containing a carbon coating layer derived from an aliphatic amine and a nitrogen doped layer on the surface of lithium titanium oxide (Li ₄ Ti ₅ O ₁₂ ) And a composite material produced by the method.

Description

[0001] The present invention relates to a method for preparing lithium-titanium oxide particles coated with carbon and nitrogen, an electrode active material and a lithium secondary battery,

TECHNICAL FIELD The present invention relates to a lithium titanium oxide particle used as a cathode material of a lithium ion secondary battery, and more particularly, to a lithium titanium oxide particle having improved conductivity by carbon coating and nitrogen doping, an electrode active material, Lithium secondary battery.

Currently, lithium secondary batteries can realize a lightweight, compact, and high energy density battery and are utilized in various fields such as portable electronic devices, electric vehicles, and energy storage devices. Generally, lithium metal oxides such as carbon, alloy-based, or Li ₄ Ti ₅ O ₁₂ are used as an anode active material, which is one of important constituent materials of lithium secondary batteries. However, the negative electrode material using the carbon material has a problem that the irreversible capacity is large, the initial charge / discharge efficiency is low, and the capacity decreases as the charge / discharge progresses. The alloy cathode material has a high capacity, but the active material is cracked and eventually broken due to a large volume change depending on charge and discharge. As a result, the irreversible capacity increases, the charge / discharge efficiency decreases, and the capacity of the battery decreases as the charge / discharge progresses.

Lithium titanium oxide has a spinel structure with a capacity of about 175 mAh / g and a potential of 1.5 V (Li ⁺ / Li) higher than that of carbon. Li ₄ Ti ₅ O ₁₂ having such a high operating voltage has an almost 100% efficiency of the initial charge and discharge cycles due to the formation of the surface coating of the cathode due to the decomposition reaction of the electrolyte, and the difference in the crystal lattice upon insertion / Zero-strain material. Compared with carbon materials, it has high structural stability, and it has advantages of low cost and easy synthesis compared with alloy system.

As mentioned above, the lithium titanium oxide is a spinel structure in which lithium and titanium form an octahedral with oxygen at the 16d position and the remaining lithium forms a tetrahedral at the 8a position. The diffusion path through which lithium is inserted is moved in the order of 8a-16c-8a, because when lithium is inserted, it occupies the 8a position. The distance between positions 8a and 16c is very close to 1.81 Å, which causes Coulomb repulsion, which causes the lithium at position 8a to slowly move to position 16c, which changes the lithium-titanium oxide into a rock salt structure. Thereafter, when lithium is continuously inserted, lithium is gradually filled in the empty space 8a. Except for the beginning and the end of the reaction the reaction by this reason _{Li 4 Ti 5 O 12, Li} 7 Ti 5 O _12, there is to the co-existence prior to reaction Li ₄ Ti ₅ O ₁₂ is very low and the electric conductivity of about 10-8 S / cm, After the reaction, Li ₇ Ti ₅ O ₁₂ transfers lithium from position 8a to position 16c, ensuring the electron conduction path and increasing the electrical conductivity to 10-2 S / cm or more. The reason why Li ₄ Ti ₅ O ₁₂ has a low electric conductivity is because Ti ^{4 +} has an electronic arrangement of [Ar] 3dO, which hinders high output characteristics and adversely affects charging and discharging at high current density do.

Patent Document 1. Korean Patent No. 1244417 Patent Document 2. Korean Patent No. 1323780 Patent Document 3. Korean Patent No. 1278832

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and it is an object of the present invention to provide a method for manufacturing a lithium titanium oxide-carbon-nitrogen composite material, which can be used as a negative electrode material of a secondary battery or a capacitor and has improved electrochemical properties.

The present invention provides a lithium titanium oxide-carbon-nitrogen composite material containing a carbon coating layer and nitrogen doping on the surface of lithium titanium oxide.

According to the present invention, the lithium titanium oxide may be Li ₄ Ti ₅ O ₁₂ and the particle size may be 0.01 to 50 μm.

According to the present invention, the carbon coating layer and the nitrogen doping may be derived from a single-molecule source containing nitrogen and carbon in the molecule, and may preferably be derived from an aliphatic amine.

According to the present invention, the total thickness of the carbon coating layer and the nitrogen doping layer may be 1 to 50 nm,

The carbon coating layer and the nitrogen doping can be contained in an amount of 70 to 99.5 atomic% of carbon and 0.5 to 30 atomic% of nitrogen, based on the total 100 atomic mass%.

According to the present invention, the sum of the carbon coating layer and nitrogen doping may be 1 to 20% by weight based on the entire lithium-titanium oxide-carbon-nitrogen composite material.

The lithium titanium oxide-carbon-nitrogen composite material containing the carbon coating layer and the nitrogen doping on the surface of the lithium titanium oxide according to the present invention can be produced by a method including the following steps.

(1) supplying carbon source and nitrogen source to lithium titanium oxide and refluxing at 80 to 120 캜 to form a carbon coating layer and nitrogen doping on the surface of lithium titanium oxide; And

(2) Carburizing step.

According to the present invention, the carbon source and the nitrogen source may be the same.

If the carbon source and the nitrogen source are identical to each other, the carbon source and the nitrogen source may be aliphatic amines or aromatic amines containing nitrogen and carbon in the molecule.

The aliphatic amine may be selected from ethylenediamine, hexamethylenediamine, diethylenetriamine, and mixtures of two or more thereof,

The aromatic amine may be selected from aniline, benzene diamine, and mixtures thereof, but is not limited thereto.

Further, according to the present invention, the carbon source and the nitrogen source may be different from each other.

If the carbon source and the nitrogen source are different from each other, the carbon source may be selected from agarose, sucrose, glucose, pitch, and a mixture of two or more thereof, and the nitrogen source may be ammonia.

According to the present invention, the step (1) may be performed by supplying 30 to 200 parts by weight of a carbon source and 10 to 50 parts by weight of a nitrogen source to 1 part by weight of lithium titanium oxide,

The carbonization in the step (2) may be carried out at 450 to 600 ° C for 3 to 6 hours to carbonize the carbon component coated on the surface of the lithium titanium oxide so as not to burn.

On the other hand, the lithium titanium oxide according to the present invention may be one produced by a manufacturing method comprising the following steps.

Dispersing lithium hydroxide, titanium oxide and a dispersant in a solvent to prepare a slurry;

Spray-drying the slurry at 200 to 300 ° C and 2 to 4 kg / cm ² ;

Calcining the spray-dried mixture at 700 to 1200 占 폚.

According to the present invention, the lithium titanium oxide may have a particle size of 0.01 to 50 탆.

According to the present invention, the lithium titanium oxide particles may be contained in 5 moles of titanium oxide with respect to 4 moles of lithium hydroxide.

According to the present invention, the dispersing agent is at least one selected from the group consisting of ethanol, a high-molecular surfactant (KD-6), N-methylpyrrolidone and polyvinylpyrrolidone, The dispersant may be contained in an amount of 2 to 10 parts by weight.

According to the present invention, the lithium titanium oxide may be Li ₄ Ti ₅ O ₁₂ .

According to the present invention, the solvent may be water.

Further, the lithium titanium oxide-carbon-nitrogen composite material containing a carbon coating layer and nitrogen doping on the surface of lithium titanium oxide (Li ₄ Ti ₅ O ₁₂ ) according to the present invention may be used as a lithium ion secondary electrode material for a lithium ion secondary battery or a capacitor Can be used.

The lithium titanium oxide-carbon-nitrogen composite material according to the present invention is manufactured by forming a carbon coating layer and nitrogen doping on lithium titanium oxide prepared by a spray drying method using a reflux method, Discharge cycle lifetime characteristics and high-rate characteristics even at a high current density, and exhibits high energy, and thus can be effectively used as a negative electrode material for a lithium secondary battery and a capacitor.

1 is a transmission electron microscope (TEM) photograph of a lithium titanium oxide-carbon-nitrogen composite material according to Example 1 of the present invention.
2 is a graph showing X-ray photoelectron spectroscopy (XPS) of a lithium titanium oxide-carbon-nitrogen composite material according to Example 1 of the present invention.
FIG. 3 is a graph of X-ray diffraction of lithium titanium oxide-carbon-nitrogen composite material according to Example 1 of the present invention to determine whether there is a structural change during carbonization a) Example 1; b) Comparative Example 1; c) Li ₄ Ti ₅ O ₁₂ ].
4 is a graph showing the rate characteristics at room temperature of a lithium secondary battery manufactured from Example 2 and Comparative Examples 1 and 2 of the present invention.

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

The present invention relates to a negative electrode active material for use as a negative electrode material of a secondary battery or a capacitor, and relates to a new negative electrode material which solves the problem of low electrical conductivity of a conventional lithium titanium oxide (Li ₄ Ti ₅ O ₁₂ ).

The present invention provides a lithium titanium oxide-carbon-nitrogen composite material containing a carbon coating layer and nitrogen doping on the surface of lithium titanium oxide.

According to the present invention, the carbon coating layer and the nitrogen doping may be coated and doped using a carbon source and a nitrogen source,

The carbon source and the nitrogen source may be the same compound each containing both nitrogen and carbon in the molecule, but the carbon source and the nitrogen source may be different from each other.

Specifically, when the carbon source and the nitrogen source are the same, the carbon source and the nitrogen source may be an aliphatic amine or an aromatic amine containing nitrogen and carbon in the molecule, and the aliphatic amine may be ethylenediamine, hexamethylenediamine, Diethylene triamine, and mixtures of two or more thereof, and the aromatic amine may be selected from aniline, benzene diamine, and mixtures thereof.

On the other hand, when the carbon source and the nitrogen source are different from each other, the carbon source may be selected from agarose, sucrose, glucose, pitch, and a mixture of two or more thereof. The nitrogen source may be ammonia, It is not.

According to the present invention, the carbon coating layer and nitrogen doping may be derived from a single-molecule source which preferably contains both carbon and nitrogen in the molecule, and more preferably may be derived from an aliphatic amine.

The carbon coating layer and the nitrogen doping are superior to the two-molecule source (source when the carbon source and the nitrogen source are different from each other) when derived from a single-molecule source containing both carbon and nitrogen in the molecule, . In particular, when the one-molecular source is an aliphatic amine, not only the aromatic amine has better conductivity but also the durability of the electrode can be improved.

According to the present invention, the lithium titanium oxide may be Li ₄ Ti ₅ O ₁₂ , and the particle size may be 0.01 to 50 μm.

The carbon coating layer and nitrogen doping formed on the surface of the lithium titanium oxide may have a thickness of 1 to 50 nm. If the thickness is less than the lower limit, it is difficult to increase the ion conductivity. If the upper limit of the range is exceeded, the specific surface area becomes small, The area is reduced and the movement of lithium ions can be prevented.

The carbon coating layer and the nitrogen doping may contain carbon in an amount of 70 to 99.5 atomic% and nitrogen in an amount of 0.5 to 30 atomic% based on 100 atomic% of the total.

The coating of carbon is preferable because it improves the current capacity of the electrode containing lithium-titanium oxide and the stability of the charge-discharge cycle.

On the other hand, the lithium titanium oxide Li ₄ Ti ₅ O ₁₂ denotes a low electrical conductivity because the Ti ^{4 +} have the electron configuration of the [Ar] 3d ^0. The nitrogen doping in accordance with the invention is to have an electron configuration of the [Ar] 3d ¹ replacing the Ti ^{4 +} to Ti ^3+, and to have a free electron. Li ₄ Ti ₅ O ₁₂ in which one free electron is generated by nitrogen doping is preferable because it exhibits high conductivity. If the content of nitrogen is out of the above range, it is difficult to expect improvement of conductivity of lithium titanium oxide by nitrogen doping.

In addition, the total amount of the carbon coating layer and the nitrogen doping may be 1 to 20 wt% based on the total amount of the lithium titanium oxide-carbon-nitrogen composite material,

The carbon coating layer and the nitrogen doping layer may contain 70 to 99.5 atom% of carbon and 0.5 to 30 atom% of nitrogen relative to 100 atom% of the total amount of the carbon coating layer and the nitrogen doping layer.

According to the present invention, when the sum of the carbon coating layer and the nitrogen doping is less than the above range based on the entire lithium-titanium oxide-carbon-nitrogen composite material, it is difficult to expect the improvement of the current capacity of the electrode and the stability of the charge- If it is contained in an amount exceeding the above range, the path through which the ions can move is lost, and the electric conductivity and the current capacity are lowered, and the life of the charge and discharge cycle is shortened and the efficiency is lowered. When the sum of the carbon coating layer and the nitrogen doping is within the above range, electrons and ions can move together, which is preferable because the electrical conductivity is greatly improved, the current capacity is increased, and the characteristics can be maintained even in repeated charge and discharge.

Next, the lithium titanium oxide-carbon-nitrogen composite material can be produced by carrying out the following steps.

(1) supplying carbon source and nitrogen source to lithium titanium oxide and refluxing at 80 to 120 캜 to form a carbon coating layer and nitrogen doping on the surface of lithium titanium oxide; And

(2) Carburizing step.

According to the present invention, for the carbonization in the step (2), the reaction mixture of the step (1) may be centrifuged to obtain a solid component, and then the obtained solid component may be dried.

According to the present invention, the carbon source and the nitrogen source are the same or different from each other,

When the carbon source and the nitrogen source are the same, the carbon source and the nitrogen source may be an aliphatic amine or an aromatic amine containing nitrogen and carbon in the molecule. Specifically, the aliphatic amine may be ethylenediamine, hexamethylenediamine , Diethylenetriamine, and mixtures of two or more thereof, and the aromatic amine may be selected from aniline, benzene diamine, and mixtures thereof.

If the carbon source and the nitrogen source are different from each other, the carbon source may be selected from agarose, sucrose, glucose, pitch, and a mixture of two or more thereof, and the nitrogen source may be ammonia.

According to the present invention, the carbon source and the nitrogen source are identical to each other, and the process is simpler than the case where the carbon source and the nitrogen source are different from each other, and the yield is excellent. In addition, since nitrogen is not biased to the carbon coating layer and can be dispersed well, the lithium titanium oxide-carbon-nitrogen composite material finally produced is excellent in conductivity. Particularly, an aliphatic amine is more preferable because the durability of the electrode is improved and the conductivity is more excellent.

According to the present invention, 30 to 200 parts by weight of a carbon source and 10 to 50 parts by weight of a nitrogen source may be supplied to 1 part by weight of lithium titanium oxide,

Or an aliphatic amine or an aromatic amine may be mixed with 40 to 200 parts by weight of an aliphatic amine per 1 part by weight of the lithium titanium oxide. If the amount is less than the above range, the aliphatic amine or aromatic amine coating layer formed on the lithium titanium oxide surface is too thin, If it exceeds the above range, the coating layer becomes too thick, the thickness of the carbon coating and the nitrogen doping layer becomes thick, the movement of lithium ions may be disturbed, and the conductivity may be deteriorated.

According to the present invention, the reflux can be performed in an air atmosphere for 12 to 24 hours. When refluxing in the same manner as described above, the aliphatic amine or the aromatic amine is concentrated and can be easily attached to the surface of the lithium titanium oxide.

On the other hand, when the carbon source and the nitrogen source are different from each other, it is preferable to block the outside air because the nitrogen source is not lost to the air.

According to the present invention, the centrifugation may be performed at 4000 to 6000 rpm for 5 to 30 minutes. The solid content thus obtained is dried in an air atmosphere at 60 to 80 占 폚 for 12 to 24 hours and then calcined by calcination taking care not to burn carbon components at 450 to 600 占 폚 for 3 to 6 hours after drying is completed.

Unlike the conventional solid phase method or sol-gel synthesis method, the 'reflux' according to the present invention can form carbon coating and nitrogen doping on the surface of lithium titanium oxide at low temperatures at one time, so that the process is simple and economical.

Next, the lithium titanium oxide can be produced by carrying out the following steps.

Dispersing lithium hydroxide, titanium oxide and a dispersant in a solvent to prepare a slurry;

Spray-drying the slurry at 200 to 300 ° C and 2 to 4 kg / cm ² ;

Calcining the spray-dried mixture at 700 to 1200 占 폚.

According to the present invention, the lithium titanium oxide may be contained in an amount of 5 moles of titanium oxide (TiO ₂ ) relative to 4 moles of lithium hydroxide (LiOH), and the dispersant may be ethanol, a polymer type surfactant (KD-6) Methylpyrrolidone, and polyvinylpyrrolidone, and may be contained in an amount of 2 to 10 parts by weight based on 100 parts by weight of the titanium oxide, and the solvent may be water.

The dispersion is not particularly limited as long as it is a dispersion method used in the process of producing lithium titanium oxide. For example, the dispersion may be performed by ball milling at 150 to 500 rpm for 3 to 12 hours.

Next, the slurry can be dried at 200 to 300 ° C and 2 to 4 kg / cm ² using a spray drying method. The dried powder can be produced by carbonization at 700 to 1200 ° C under an air atmosphere for 6 to 12 hours.

Hereinafter, the present invention will be described in more detail with reference to preferred embodiments. It will be apparent to those skilled in the art, however, that these examples are provided to further illustrate the present invention, and the scope of the present invention is not limited thereto.

Production Example 1. Preparation of Lithium Titanium Oxide

A mixture of lithium hydroxide (LiOH) and titanium oxide (TiO ₂ ) in a 4: 5 molar ratio and dispersing agent (5% by weight of the amount of TiO ₂ ) (Ball mill) for 12 hours to prepare a slurry. The prepared slurry was dried at 250 ° C. at 3 kg · cm ^-2 using a spray drying method and then carbonized at 900 ° C. for 12 hours in an air atmosphere to prepare lithium titanium oxide.

Example 1. Preparation of Lithium Titanium Oxide-Carbon-Nitride Composite Material

1 part by weight of the lithium titanium oxide prepared in Preparation Example 1 was mixed with 100 parts by weight of aliphatic amine and refluxed at 100 ° C for 12 hours in an air atmosphere. The reaction mixture was concentrated to coat an aliphatic amine on the surface of the lithium titanium oxide. The reaction mixture was centrifuged to separate an aliphatic amine-coated lithium titanium oxide. The separated material was dried at 70 DEG C for 12 hours in an air atmosphere and carbonized at 450 to 800 DEG C for 3 to 12 hours after the completion of drying, taking care not to burn the carbon material, thereby obtaining a lithium titanium oxide- .

In the lithium titanium oxide - carbon - nitrogen composite material, the carbon content was 5.9 wt% and the nitrogen content was 1.7 wt%.

Example 2. Preparation of Lithium Battery Using Lithium Titanium Oxide-Carbon-Nitride Composite Material

The lithium titanium oxide-carbon-nitrogen composite material, the conductive agent (Acetylene Black) and the binder (Polyvinylidene Fluoride) (PVDF) were mixed at a weight ratio of 80:10:10 prepared in Example 1, N-methylpyrrolidone (NMP) as a dispersant, and the mixture was uniformly stirred using a stirrer to prepare a slurry.

The slurry was applied to a copper foil, dried at 60 DEG C for 12 hours, and compressed using a rolling press to produce an electrode. The squeezed electrode was punched to 12 Ø, and mass was measured using a microbalance, and only the mass of the lithium titanium oxide-carbon-nitrogen composite excluding conductive agent, binder and foil was determined. The compressed electrode was dried in a vacuum oven at 80 캜 for 12 hours to prepare a composite electrode. A button cell (coin cell) was fabricated using the electrode thus prepared, and a lithium battery was manufactured using lithium metal as a counter electrode.

Comparative Example 1

A lithium battery was prepared in the same manner as in Example 1 except that the lithium titanium oxide prepared in Preparation Example 1 was used instead of the lithium titanium oxide-carbon-nitrogen composite material prepared in Example 1.

Comparative Example 2

Instead of the lithium titanium oxide-carbon-nitrogen composite material finally produced in Example 1, carbon-coated lithium titanium oxide was prepared using the pitch in the lithium titanium oxide prepared in the step (a) of Example 1 , And a lithium battery was produced by the method of Example 2 using the same. The content of carbon was 5.9 wt%.

Test Example 1

The lithium titanium oxide-carbon-nitrogen composite material prepared according to Example 1 of the present invention was photographed with a transmission electron microscope (TEM), which is shown in FIG.

Referring to FIG. 1, it can be confirmed that carbon is uniformly coated on the lithium titanium oxide (Li ₄ Ti ₅ O ₁₂ ) anode active material to a thickness of about 2 nm.

Test Example 2

Nitrogen doping was confirmed by measuring the lithium titanium oxide-carbon-nitrogen composite material prepared according to Example 1 of the present invention using an X-ray photoelectron spectroscopy (XPS) apparatus. .

Referring to FIG. 2, it can be seen that nitrogen was detected in the lithium-titanium oxide-carbon-nitrogen composite material of Example 1 which is the upper graph, but nitrogen was not detected in the lithium-titanium oxide of Comparative Example 1 in the lower graph.

Test Example 3.

The carbon coating and nitrogen-doped lithium titanium oxide prepared by the reflux method according to Example 1 were analyzed by X-ray diffractometry to confirm that the structure of the material was deformed through a high heat treatment as compared with the lithium titanium oxide of the comparative example, This is shown in FIG.

Referring to FIG. 3, it can be seen that the structure of the material of the lithium-titanium oxide-carbon-nitrogen composite material according to Example 1 was not deformed.

The carbon coating and the nitrogen-doped lithium titanium oxide show that the crystal structure of the uncoated lithium titanium oxide is maintained despite the high reflux temperature and that carbon or nitrogen does not form another crystal structure by chemical bonding with lithium titanium oxide Can be confirmed. As a result, it can be confirmed that the lithium ion can form a structure that can be de-intercalated in the crystal structure like the lithium-titanium oxide not coated.

Test Example 4.

In order to evaluate the characteristics of the electrode according to the voltage, the discharge capacity according to the number of charging / discharging cycles was measured. The electrode prepared in Example 2 and Comparative Examples 1 and 2 was used as a working electrode of a half cell and a lithium metal was used as a counter electrode and as a separator, Polypropylene (PP), in which the electrolyte was wetted, was used. As the electrolyte, a mixed solution in which 1.2 M LiPF 6 salt was dissolved in ethylene carbonate (EC) and diethyl carbonate (DEC) in a volume ratio of 1: 1 was used. The fabricated half cell was fabricated with Coin 2032 type. All processes in the cell assembly proceeded in a glove box where relative humidity and oxygen were always kept below 0.1 ppm.

The electrode using the carbon coating and the nitrogen-doped lithium titanium oxide according to Example 2 exhibited a discharge capacity as high as about 180 mAh / g under the condition of 1 C current due to the improved electric conductivity, Capacity was maintained above 95%. On the other hand, the electrode of Comparative Example 1 exhibited a discharge capacity of about 153 mAh / g at a current of 1 C, the discharge capacity of the electrode of Comparative Example 2 was about 167 mAh / g, The discharge capacity was maintained at less than 90%.

Test Example 5

A half cell was prepared in the same manner as in Test Example 4. The cut-off voltage was set to 1.0 V to 3.0 V, and the rate characteristics were measured. The charging and discharging currents were measured using the same current intensity and were measured at 0.2 C (35 mAh / g), 0.5 C (87.5 mAh / g), 1 C ), 5 C (875 mAh / g), 10 C (1750 mAh / g) and 20 C (3500 mAh / g) mAh / g).

Referring to FIG. 4, the electrode of Example 1 showed an excellent discharge capacity of 180 mAh / g at 1 C or lower, and a discharge capacity of about 150 mAh / g even at 10 C. On the other hand, the discharge capacity of the electrode of Comparative Example 1 was about 150 mAh / g at 1 C, and it was greatly reduced to 80 mAh / g at 20 C. On the other hand, the electrode of Comparative Example 2 exhibited a discharge capacity of about 167 mAh / g at 1 C, about 155 mAh / g at 5 C, and about 120 mAh / g at 20 C and the lithium-titanium oxide- Showed improved electrochemical properties such as conductivity by carbon coating and nitrogen doping.

Claims (19)

delete delete delete delete delete (1) A method for producing a lithium battery, comprising the steps of: (1) mixing a lithium titanium oxide and an aliphatic amine selected from ethylenediamine, hexamethylenediamine, diethylenetriamine, and a mixture of two or more thereof and refluxing at 80 to 120 ° C to form a carbon coating layer and a nitrogen Forming doping; And
And (2) carbonizing the lithium titanium oxide-carbon-nitrogen composite material. delete delete delete delete The method according to claim 6,
Wherein the lithium titanium oxide is mixed with 100 parts by weight of the aliphatic amine per 1 part by weight of the lithium titanium oxide. The method according to claim 6,
Wherein the carbonization in the step (2) is performed at 450 to 600 ° C for 3 to 6 hours. The method according to claim 6,
Wherein the lithium titanium oxide is prepared by dispersing lithium hydroxide, titanium oxide and a dispersant in a solvent to prepare a slurry; Spray-drying the slurry at 200 to 300 ° C and 2 to 4 kg / cm ² ; And calcining the spray-dried mixture at 700 to 1200 ° C. [Claim 6] The method according to claim 1, wherein the lithium-titanium oxide-carbon-nitrogen composite material is calcined at 700 to 1200 ° C. 14. The method of claim 13,
Wherein the lithium titanium oxide is contained in 5 moles of titanium oxide per 4 moles of lithium hydroxide. 14. The method of claim 13,
The dispersant may be at least one selected from the group consisting of ethanol, a high-molecular surfactant (KD-6), N-methylpyrrolidone and polyvinylpyrrolidone, and the dispersant is contained in an amount of 2 to 10 parts by weight per 100 parts by weight of the titanium oxide. Wherein the lithium titanium oxide-carbon-nitrogen composite material is a lithium titanium oxide-carbon composite material. The method according to claim 6,
Wherein the carbon coating layer and nitrogen doping are 1 to 20 wt% based on the total amount of the lithium titanium oxide-carbon-nitrogen composite material,
Carbon composite material according to claim 1, wherein carbon is contained in an amount of 70 to 99.5 atomic% and nitrogen is contained in an amount of 0.5 to 30 atomic% with respect to 100 atomic% of the total amount of the carbon coating layer and nitrogen doping. delete A lithium ion secondary battery comprising the lithium titanium oxide-carbon-nitrogen composite material produced by the manufacturing method according to any one of claims 6 and 11 to 16. 16. A capacitor comprising a lithium titanium oxide-carbon-nitrogen composite material produced by the process according to any one of claims 6 to 11.

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