KR100613260B1 - Negative active material for lithium secondary battery, method of preparing same, and lithium secondary battery comprising same - Google Patents

Abstract

The present invention relates to a negative electrode active material for a lithium secondary battery, a method of manufacturing the same, and a lithium secondary battery including the same, and more particularly, through a heat treatment by mixing a carbonaceous precursor and a precursor containing a metal-containing carbon modifying element, The present invention relates to a negative electrode active material for a lithium secondary battery in which a carbon element and a metal-containing carbon modifying element are dispersed, and micropores are formed, and a method of manufacturing the same.

The negative electrode active material is one of transition metals, alkali metals, alkaline earth metals, group 3A, 3B, 4A and 4B semimetals, 5A, 5B, lanthanum-based or actinium-based elements, which are elements capable of modifying the surrounding carbon structure. Including the above, it exhibits the high capacity characteristics of the metal and non-metallic elements and the high output characteristics of carbon derived from the carbonaceous precursor, and due to the expansion of the electrode during the occlusion reaction of lithium ions due to the fine pores present in the negative electrode active material The crack can be prevented, effectively increasing the charge and discharge cycle and life of the lithium secondary battery.

Lithium secondary batteries, carbonaceous precursors, metal-containing carbon modifiers, high capacity, high efficiency, charge and discharge cycles, lifetime

Description

A negative active material for a lithium secondary battery, a method of manufacturing the same, and a lithium secondary battery including the same TECHNICAL FIELD

Figure 1a is a scanning electron microscope (SEM) photograph showing the surface state of the negative electrode active material prepared in Example 1.

Figure 1b is a scanning electron microscope (SEM) photograph showing the surface state of the negative electrode active material prepared in Comparative Example 1.

Figure 2a is an energy dispersive X-ray spectrophotometer (EDX) photograph showing the dispersion state of the silicon particles of the negative electrode active material prepared in Example 1.

Figure 2b is an energy dispersive X-ray spectroscopy (EDX) photograph showing the dispersion state of the silicon particles of the negative electrode active material prepared in Comparative Example 1.

[Industrial use]

The present invention relates to a negative electrode active material for a lithium secondary battery, which exhibits a high capacity and a high output, and to which the charge and discharge characteristics and life of the battery are increased, a method of manufacturing the same, and a lithium secondary battery including the same.

[Private Technology]

The negative electrode active material for a lithium secondary battery requires high efficiency and excellent cycle characteristics, and carbonaceous negative electrode active materials such as natural graphite and artificial graphite are mainly used as such materials. However, the carbonaceous negative electrode active material described above cannot be discharged beyond the theoretical capacity of 372 mAh / g, which is not suitable for the next generation high capacity and / or high output lithium secondary battery.

Accordingly, metal anode active materials such as silicon (Si), tin (Sn), and lithium (Li) as negative electrode active materials of lithium secondary batteries since the 1990s; Tin-antimony (Sn-Sb), silicon-tin (Si-Sn), tin-copper (Sn-Cu), lithium-silicon (Li-Si), lithium-tin (Li-Sn), and lithium-antimony (Li Alloy negative electrode active materials such as -Sb); And research on the nitride-based negative active material of Li-Co-N is in progress. However, although the lithium secondary battery prepared with the metal-based negative electrode active material has a high initial capacity of 600 mAh / g or more and some of 1000 mAh / g or more, it is reported that it is difficult to apply to practical use due to the inferior charge / discharge cycle characteristics. (Sato et al .; automotive high-capacity rechargeable batteries, published by CMC , 2003).

As described above, the metal-based negative active material has an irreversible chemical component among the components participating in the chemical reaction, and thus the charge / discharge cycle is inferior. In addition, during the intercalation reaction of lithium ions due to charging, the expansion of the metal is so large that the volume of the electrode expands to about several hundred times, resulting in the expansion or contraction of the electrode due to the high expansion / contraction. It may be destroyed.

In order to prevent the deterioration of the charge / discharge cycle characteristics of the lithium secondary battery employing the metal-based negative electrode active material, studies have been conducted such as nano-size metal negative electrode active materials, but have not yet reached practical use.

On the other hand, a carbon-metal composite material is proposed in which the surface of a carbon-based material as a negative electrode active material is coated with silicon by chemical vapor deposition (CVD) (cell technology, 14 3-13, 2002). However, such a method also has a nonuniform coating reaction and is limited in application in a continuous process, and thus it is difficult to reach practical use.

An object of the present invention for solving the above problems is to provide a negative electrode active material for a lithium secondary battery excellent in high capacity, high output characteristics and charge and discharge cycle characteristics and a method of manufacturing the same.

In addition, another object of the present invention to provide a lithium secondary battery comprising the negative electrode active material.

In order to achieve the above object, the present invention is a lithium containing a composite comprising a carbon element and a metal-containing carbon modified element capable of modifying the carbon structure and the surrounding carbon structure is dispersed, micropores formed Provided is a negative active material for a secondary battery.

In addition, the present invention is a carbon-based material; And

A composite comprising a carbon-element-containing carbon-modified element on which the metal-containing carbon-modified element, which is present on the surface of the carbon-based material and capable of modifying the carbon element and the surrounding carbon structure, is dispersed and micropores are formed.

It provides a negative electrode active material for a lithium secondary battery comprising a.

The metal-containing carbon modifying element may be one or more of transition metals, alkali metals, alkaline earth metals, Group 3A, Group 3B, Group 4A and Group 4B semimetals, Group 5A, Group 5B, lanthanum series or actinium series elements.

In this case, the negative electrode active material further includes one negative electrode active material selected from amorphous carbon or crystalline carbon which is a conventional negative electrode active material.

In addition, the present invention

Iii) mixing a precursor comprising a carbon precursor and a metal containing carbon modifying element;

Ii) first heat treating the obtained precursor mixture; And

Iii) a second heat treatment of the heat treated mixture in a non-oxidizing atmosphere

It provides a method for producing a negative electrode active material for a lithium secondary battery comprising a carbon-metal-containing carbon modifying element comprising a.

In addition, the present invention

Iii) mixing a precursor comprising a carbon precursor and a metal containing carbon modifying element;

Ii) applying the carbonaceous material to the precursor mixture obtained above so that the precursor mixture is coated on the surface of the carbonaceous material;

Iii) first heat treatment of the precursor mixture obtained above; And

Iii) a second heat treatment of the mixture heat treated in a non-oxidizing atmosphere

Including a, it provides a method for producing a negative electrode active material for a lithium secondary battery coated with a composite comprising a carbon-based material and a carbon-metal-containing carbon modifying element on the surface of the carbon-based material.

At this time, the first heat treatment is performed at 150 to 200 ℃, the second heat treatment is performed at 500 to 1300 ℃.

Preferably, the carbonaceous precursor is used solid carbon or liquid carbon.

The precursor containing the metal-containing carbon modifying element has one form selected from the group consisting of alkoxides, salts, oxides, sulfides, hydroxides and hydrides containing the elements as described above.

The present invention also includes a negative electrode comprising the negative electrode active material;

A positive electrode including a positive electrode active material capable of reversible intercalation / deintercalation of lithium; And

An electrolyte located between the cathode and the anode;

It provides a lithium secondary battery comprising a.

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

In the negative electrode active material of the present invention, a carbon-metal-containing carbon-modified element composite including a carbon element and a carbon-modified element is used as it is, or is applied to the surface of a conventional carbon-based material. In this case, the carbon-metal composite has a structure in which carbon elements and metal-containing carbon modifying elements are uniformly dispersed and fine pores are formed.

The carbon element has a high structural stability during charge and discharge and a relatively good charge and discharge cycle efficiency, but has a small capacity, and thus has a disadvantage in that the carbon element uses a carbon-containing carbon modifier to improve the problem of the carbon element. To form a modified element complex.

The carbon element is obtained by heat treatment of the carbonaceous precursor, the carbonaceous precursor is converted to a crystalline or semi-crystalline state after the heat treatment, some carbon is converted to carbon monoxide or carbon dioxide by an oxide containing a metal-containing carbon modifying element, the cathode Fine pores of the active material are formed.

When used as a negative electrode active material, the fine pores are used as an expansion space of the active material by occlusion of lithium, thereby preventing cracking in the negative electrode. Accordingly, the negative electrode active material according to the present invention is composed of a carbon-metal composite to have high capacity characteristics of carbon and high efficiency of metal at the same time, thereby effectively improving the charge / discharge cycle characteristics of the lithium secondary battery and the battery life.

The carbonaceous precursor according to the present invention may be solid carbon or liquid carbon which is commonly used, and is not particularly limited in the present invention. Typically, the solid carbon may be obtained by heat-treating a phenol resin, naphthalene resin, polyvinyl alcohol resin, urethane resin, polyimide resin, furan resin, furfuryl alcohol, cellulose resin, epoxy resin, polystyrene resin, and the like at about 1000 ° C. have. In addition, the mesophase pitch of raw petroleum, coal-based carbon raw material or resin-based carbon heat treated at 300 to 600 ° C., raw cokes and raw carbon after heat treatment at 600 to 1500 ° C. after infusible treatment or without infusible treatment. Amorphous carbons such as mesophase pitch carbide, calcined coke and the like are possible. The liquid carbon may be one selected from the group consisting of coal-based pitch, petroleum-based pitch, tar, tar and low molecular weight heavy oil at a temperature of about 1000 ° C.

On the other hand, the "metal-containing carbon modifying element" referred to throughout this specification is converted to an oxide after the first heat treatment, reduced after the second heat treatment to exist as the element itself, and oxygen in the oxide is a carbonaceous precursor around By means of reacting with the carbon derived from the carbon dioxide or carbon monoxide is converted to a gas means an element capable of forming fine pores in the carbon-metal-containing carbon modified element structure.

Preferably, the metal-containing carbon modifying element is one or more of transition metals, alkali metals, alkaline earth metals, Group 3A, Group 3B, Group 4A and Group 4B semimetals, Group 5A, Group 5B, Lanthanum-based or Actinium-based elements It is possible. More preferably transition metals of Mn, Ni, Fe, Cr, Co, Cu, Mo, W, Te, Re, Ru, Os, Rh, Ir, Pd or Pt, alkali metals of Li, Na or K, Be, Alkaline earth metal of Sr, Ba, Ca or Mg, group 3A semimetal of Sc, Y, La or Ac, group 3B semimetal of B, Al or Ga, group 4A semimetal of Ti, Zr or Hf, Si, Ge or Group 4B semimetals of Sn, Group 5A elements of V, Nb or Ta, Group 5B elements of P, Sb or Bi, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm Or at least one of lanthanum-based elements of Yb or Lu, or actinium-based elements of Th, U, Nb or Pu. Most preferably one or more elements selected from the group consisting of Si, Sb, Sn and Li are possible.

The metal-containing carbon modifying element is preferably present in a liquid state to facilitate mixing with the carbonaceous precursor, and includes one type selected from the group consisting of alkoxides, salts, oxides, sulfides, hydroxides and hydrides. Applied as precursor.

The content of the metal-containing carbon-modified element is a composite including the entire carbon-metal-containing carbon-modified element such that carbon remains after some carbons derived from the carbonaceous precursor are destroyed by the generation of carbon dioxide in the final heat treatment step. When the content of the metal-containing carbon-modifying element is less than 1% by weight, the formation of fine pores is insufficient, and the modification of carbon occurs less, so that the initial charge and discharge efficiency is insignificant. Become. In addition, as the content of the metal-containing carbon-modifying element increases, the carbon-modifying effect increases, but when the content exceeds 90% by weight, the effect increase is insignificant.

In addition, the present invention increases the self-filling capacity by coating the composite including the carbon element-metal containing carbon modifying element on a conventional negative electrode active material as described above. The negative electrode active material is applied to the surface of the composite including the carbon element-metal-containing carbon modifying element, to prepare a negative electrode active material of the core-shell type (core-shell type).

The negative electrode active material used in the present invention is preferably a carbon-based material, crystalline carbon such as natural graphite, artificial graphite, graphite carbon fiber, and the like, and solid carbon, petroleum, and the like as known in the art. Amorphous carbon obtained by treating coal-based carbon raw materials, resin-based carbon, or the like is possible, and preferably crystalline carbon in a powder state is used. In this case, the solid carbon may be obtained by heat-treating a phenol resin, naphthalene resin, polyvinyl alcohol resin, urethane resin, polyimide resin, furan resin, fufuryl alcohol, cellulose resin, epoxy resin, polystyrene resin and the like at about 1000 ° C. . In addition, the mesophase pitch of raw petroleum, coal-based carbon raw material or resin-based carbon heat treated at 300 to 600 ° C., raw cokes and raw carbon after heat treatment at 600 to 1500 ° C. after infusible treatment or without infusible treatment. Amorphous carbons such as mesophase pitch carbide, calcined coke and the like are possible. The liquid carbon may be one selected from the group consisting of coal-based pitch, petroleum-based pitch, tar, tar and low molecular weight heavy oil at a temperature of about 1000 ° C.

In this case, the carbonaceous material is a carbonaceous precursor and a carbon modified element precursor mixture in order to sufficiently coat the surface of the carbon element-metal-containing carbon modified element composite to obtain an effect according to the metal-containing carbon modified element It is preferable to use the carbon-based material at least 1 part by weight or more with respect to 100 parts by weight, and may be used in an excessive amount with respect to the content of the mixture, and may be used up to 1000 parts by weight with respect to 100 parts by weight of the mixture. .

The negative electrode active material of the present invention having such a composition

Iii) mixing a precursor comprising a carbonaceous precursor and a metal containing carbon modifying element;

Ii) first heat treating the obtained precursor mixture; And

V) The heat-treated mixture is prepared by a second heat treatment in a non-oxidizing atmosphere.

Hereinafter, each step will be described in more detail.

Iii) preparing the precursor mixture

In this step, a carbon-metal composite precursor is prepared by mixing a precursor including a carbon precursor and a metal-containing carbon modifying element in a predetermined ratio. At this time, the type and content of the precursor including each carbonaceous precursor and the metal-containing carbon modifying element are as described above.

In the mixing method, the carbonaceous precursor may vary depending on a solid phase or a liquid phase, and the carbonaceous precursor may be diluted with a solvent to facilitate mixing. The dilution solvent may be at least one selected from the group consisting of organic solvents such as water, ethanol, isopropyl alcohol, toluene, benzene, hexane and tetrahydrofuran and mixtures thereof, wherein the dilution concentration may be uniformly mixed. Degree of concentration is preferred and can be appropriately adjusted by one of ordinary skill in the art.

Ii) first heat treatment step

In this step, the precursor mixture prepared in step iii) is subjected to a heat treatment under an oxidizing atmosphere of less than 300 ° C, preferably 150 to 300 ° C.

During the first heat treatment process, the precursor containing the carbonaceous precursor and the metal-containing carbon modifying element undergoes a polycondensation reaction.

Iii) second heat treatment step

In this step, the first heat-treated mixture in step ii) is heat-treated under a reducing atmosphere of 500 to 1300 ° C. to prepare a negative electrode active material including a composite including a carbon-metal-containing carbon modifying element.

In this case, the compound containing the metal-containing carbon-modified element polycondensed through the first heat treatment is converted into an oxide containing the metal-containing carbon-modified element at about 500 ℃ or less at the temperature rise for the second heat treatment, such an oxide Is reacted with carbon derived from a carbon precursor surrounding the oxide at 500 ° C. or higher to be reduced to metal, and the carbon is oxidized to carbon dioxide (or carbon monoxide) (see (1) in Scheme 1 below). The carbon dioxide (or carbon monoxide) is present in a gaseous state and released during heat treatment to form fine pores (or voids) corresponding to the carbon dioxide (or carbon monoxide). As an example, the chemical reaction in the second heat treatment step using silicon is shown in Scheme 1 below.

According to Scheme 1, the second heat treatment is performed at 500 to 1300 ° C., and if the heat treatment temperature is less than 500 ° C., the carbonization reaction of the carbonaceous precursor in the carbon-metal composite precursor is not terminated, thereby polymerizing the carbonaceous precursor May remain and is undesirable. In addition, when it exceeds 1300 ℃, the metal precursor is not reduced to the metal, and may react with the carbon derived from the carbonaceous precursor to transition to carbides, the presence of carbide in the negative electrode active material reduces the electrical conductivity of the negative electrode active material This eventually lowers the performance of the negative electrode active material.

Particularly, although the formation of carbides such as SiC mentioned above may occur at 1000 ° C. or above, as shown in the above reaction formula (2), such carbides are produced when heat-treated for a very long time. This is not a concern.

At this time, the heat treatment is carried out under a reducing atmosphere to facilitate the reduction reaction of the metal, preferably by injecting hydrogen, nitrogen and argon alone and a mixed gas thereof.

The composite containing the carbon element-metal-containing carbon modified element prepared by the above method is a carbon element and a metal-containing carbon modified element capable of modifying the surrounding carbon structure is dispersed, and has a structure containing fine pores, lithium It is preferably applicable as a negative electrode active material for secondary batteries.

In addition, the present invention is a carbon-based material; And a metal-containing carbon-modified element present on the surface of the carbon-based material and capable of modifying the carbon element and the surrounding carbon structure, wherein the carbon-containing metal-modified carbon-modified element is formed with fine pores.

The core-shell type negative electrode active material is

Iii) mixing a precursor comprising a carbon precursor and a metal containing carbon modifying element;

Ii) applying the carbonaceous material to the precursor mixture obtained above so that the precursor mixture is coated on the surface of the carbonaceous material;

Iii) first heat treatment of the precursor mixture obtained above; And

Iii) the mixture is heat-treated in the above non-oxidizing atmosphere is prepared through a second heat treatment step.

In the case where the carbon-based material is further mixed with the precursor mixture obtained in step iii), after mixing the respective precursors, the carbon-based material is mixed at a predetermined ratio. Preferably, the composition and content of the carbonaceous material is as described above.

When the carbon-based material is a solid phase, the coating process may be mainly performed by a mechanical mixing method. As an example of the mechanical mixing method, a kneading method and a shear stress may occur during mixing. Or a mechanical mixing method that changes the wing structure of the blade) or mechanically applies a shear force between particles to induce fusion between particle surfaces.

In the case of mixing in a liquid phase, as in the case of mixing in a solid phase, mechanical mixing, spray drying, spray pyrolysis, or freeze drying may be performed. In the case of liquid phase mixing, it is diluted with a solvent and used as said carbonaceous precursor added.

The first and second heat treatment processes thereafter are performed in the same manner as described above.

The lithium secondary battery according to the present invention includes a negative electrode active material comprising a carbon-metal composite according to the present invention, a negative electrode including a conductive material and a binder, a normal positive electrode active material, a positive electrode including a conductive material and a binder, and An electrolyte located between the positive and negative electrodes. In this case, the separator may be further included or not included depending on the electrolyte.

The conductive material includes nickel powder, cobalt oxide, titanium oxide, ketjen black, acetylene black, furnace black, graphite, carbon fiber, and fullerene which are commonly used, and the positive electrode active material is also known in the art, and reversibly intercalates lithium. LiMn ₂ O ₄ , LiCoO ₂ , LiNiO ₂ , LiFeO ₂ , V ₂ O ₅ , TiS, and MoS, which are compounds capable of being calcinated / deintercalated, can be used. At this time, the separator may be a polyolefin-based polymer membrane such as polyethylene or polypropylene, or a known membrane such as a multilayer, microporous film, woven fabric, or nonwoven fabric.

Examples of the electrolyte include carbonates; Tetrahydrofuran system; LiPF ₆ , LiBF ₄ , LiSbF ₆ , LiAsF ₆ , LiClO ₄ , LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, LiC ₄ F ₉ SO ₃ , LiSbF ₆ , LiAlO ₄ , LiAlCl ₄ , LiN (CxF _{2x + 1} SO ₂ ) (CyF _{2y + 1} SO ₂ ) (where x and y are natural numbers), What melt | dissolved what mixed 1 type (s) or 2 or more types of electrolytes which consist of lithium salts, such as LiCl and LiI, can be used.

In addition, a polymer solid electrolyte may be used instead of the electrolyte solution. In this case, it is preferable to use a polymer having high ion conductivity with respect to lithium ions, and polyethylene oxide, polypropylene oxide, polyethyleneimine and the like can be used. It is also possible to use a gel in which the solvent and the solute are added to the polymer of.

The lithium secondary battery may have a cylindrical shape, but may have various shapes such as a cylindrical shape, a square shape, a coin shape or a sheet shape.

As described above, the lithium secondary battery according to the present invention employs a negative electrode active material capable of exhibiting high capacity and high power, thereby allowing small batteries such as mobile phones and laptops, electric vehicles, hybrid electric vehicles (HEVs), and fuel cell vehicles (Fuel). It can be preferably applied to large batteries used in transportation devices such as Cell Electric Vehicles (FCEV) and battery scooters.

The present invention will be described in more detail with reference to the following examples. However, the following examples are only preferred embodiments of the present invention, and the present invention is not limited to the following examples.

Example 1

To prepare a carbon-silicon composite as a negative electrode active material, first, a liquid phenolic resin is used as a carbonaceous precursor, and tetraethyl ortho silicate (TEOS, Si (OH) ₄ ) is used as a metal precursor. Dilute to 1: 2 in furan (THF) to prepare a composite precursor.

The prepared composite precursor was mixed with a graphite-based negative electrode active material (capacity 360mAh / g, efficiency 85%) in a ratio of C: Si = 5: 1 to coat the negative electrode active material with the composite precursor.

After the obtained mixture was subjected to polycondensation by heat treatment at 200 ° C. for 24 hours, and then heat treatment at mixed gas atmosphere (hydrogen / nitrogen = 9/1) for 10 hours at 700 ° C. to modify the carbon-silicon composite. A negative electrode active material was prepared.

Comparative Example 1

A high purity (99%, 325 mesh) silicon metal was mixed with the same graphite powder as in Example 1 to prepare an anode active material in which silicon metal and graphite powder were dispersed.

Experimental Example 1

In order to determine the surface state of the negative electrode active material prepared in Example 1 and Comparative Example 1 was measured using SEM / EDX, the results obtained are shown in Figures 1a to 2b.

1A and 1B are scanning electron micrographs showing negative electrode active materials prepared in Example 1 and Comparative Example 1, respectively, and FIGS. 2A and 2B are energy dispersive X-ray spectroscopy photographs showing the degree of silicon distribution in each.

Referring to FIGS. 1A and 1B, the negative active material (FIG. 1A) prepared by the present invention may exist in a state of particles having a uniform size, and it may be predicted that silicon is uniformly formed on a surface thereof. In contrast, in the case of the negative electrode active material prepared in Comparative Example 1 shown in FIG. 1B, the graphite powder and the silicon particles are separated from each other.

In addition, in the energy dispersive x-ray analyzer (EDX) analysis, the negative electrode active material of Example 1 according to the present invention was compared with that in which silicon was uniformly dispersed (FIG. 2A), and Comparative Example 1 It can be seen that (Fig. 2b) is a silicon metal is distributed separately from the graphite powder.

These results can be seen more clearly in the charge and discharge cycle characteristics measured below.

Experimental Example 2 Characteristics of Charge and Discharge Cycles

A: battery manufacturing

Using the negative electrode active material prepared in Example 1 and Comparative Example 1, a negative electrode was prepared by a conventional method and a charge and discharge test was performed.

First, the negative electrode active material and the polyvinylidene fluoride (PVdF, Aldrich, weight average molecular weight (Mw.): 534,000) binders prepared in Example 1 and Comparative Example 1 were 1-methyl- in a ratio of 90:10. After mixing in 2-pyrrolidone (1-Methyl-2-Pyrrolidinone (NMP, Aldrich), stirring to have an appropriate viscosity, and coating the copper foil (Cu foil), the current collector to the thickness of about 50 ㎛ by the doctor blade method It was.

After drying the copper foil having the negative electrode active material layer was pressed using a roll roll (roll press), it was cut in a circular shape, cut to fit the size of the cell was used as a negative electrode.

The negative electrode was dried again in a vacuum dryer to prepare a cell in the form of a coin cell (coin cell) in a glove box. In this case, the manufactured electrode was used as a working electrode, a Li hoil was used as a counter and a reference electrode, and a polyethylene material was used as a separator. In this case, 1 M LiPF ₆ salt was dissolved in an ethylene carbonate / diethyl carbonate (Ethylene carbonate; EC) / (diethyl carbonate; DEC) electrolyte in a volume ratio of 1: 1.

B: charge and discharge test

Charge and discharge tests were measured using a constant current constant voltage test method using a charge and discharge tester (Toscat 3100, Toyo.).

First, the battery was charged with a current density of 0.1 C, and then constant voltage charged at 10 mV, and cut-off at a current of 5% of 1 C. The discharge was galvanostatic and cut-off at 2.0 V with a current density of 0.1 C.

As a result, the negative electrode active material of Example 1 according to the present invention had a capacity of 372 mAh / g and had an efficiency of 90%, compared with graphite powder (capacity 360 mAh / g, 85% efficiency) used as a core. And efficiency.

On the other hand, the negative electrode active material of Comparative Example 1 had a capacity of 560 mAh / g and an efficiency of 60%, which greatly increased the capacity compared with the graphite powder of the core (capacity 360 mAh / g, efficiency of 85%), but the efficiency decreased significantly. The results are shown.

As described above, the manufacturing method according to the present invention may produce a negative active material for a lithium secondary battery coated with a carbon-based powder with a carbon-metal composite. The obtained negative electrode active material has high capacity characteristics of carbon and high efficiency characteristics of metal at the same time, thereby effectively improving the charge / discharge cycle characteristics of the lithium secondary battery and the battery life.

Claims (25)

A negative electrode active material for a lithium secondary battery, comprising a composite comprising a carbon element and a metal-containing carbon modifying element capable of modifying the surrounding carbon structure, wherein the carbon element-metal-containing carbon modifying element has fine pores formed therein. The method of claim 1, wherein the metal-containing carbon-modified element is a transition metal, alkali metal, alkaline earth metal, Group 3A, Group 3B, Group 4A and Group 4B semimetals, Group 5A, Group 5B, Lanthanum-based, Actinium-based elements, and An anode active material comprising an element selected from the group consisting of a combination of these. The method of claim 2, wherein the transition metal is selected from the group consisting of Mn, Ni, Fe, Cr, Co, Cu, Mo, W, Te, Re, Ru, Os, Rh, Ir, Pd and Pt, the alkali The metal is selected from the group consisting of Li, Na and K, the alkaline earth metal is selected from the group consisting of Be, Sr, Ba, Ca and Mg, the Group 3A semimetal is the group consisting of Sc, Y, La and Ac Group 3B semimetal is selected from the group consisting of B, Al and Ga, the Group 4A semimetal is selected from the group consisting of Ti, Zr and Hf, the Group 4B semimetal is Si, Ge and It is selected from the group consisting of Sn, the Group 5A element is selected from the group consisting of V, Nb and Ta, the Group 5B element is selected from the group consisting of P, Sb and Bi, the lanthanum-based element is Ce, Pr , Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, wherein the actinium-based elements are Th, U, Nb, Pu, and their groups An anode active material comprising an element selected from the group consisting of a sum. The negative electrode active material of claim 1, wherein the metal-containing carbon modifying element is contained in an amount of 1 to 90% by weight based on the composite including the entire carbon element-metal-containing carbon modifying element. Carbon-based materials; And A composite comprising a carbon-element-containing carbon-modified element on which the metal-containing carbon-modified element, which is present on the surface of the carbon-based material and capable of modifying the carbon element and the surrounding carbon structure, is dispersed and micropores are formed. A negative electrode active material for a lithium secondary battery comprising a. The method of claim 5, wherein the metal-containing carbon-modified element is a transition metal, alkali metal, alkaline earth metal, Group 3A, Group 3B, Group 4A and Group 4B semimetals, Group 5A, Group 5B, lanthanum series, actinium-based elements, and An anode active material comprising an element selected from the group consisting of a combination of these. The method of claim 6, wherein the transition metal is selected from the group consisting of Mn, Ni, Fe, Cr, Co, Cu, Mo, W, Te, Re, Ru, Os, Rh, Ir, Pd and Pt, the alkali The metal is selected from the group consisting of Li, Na and K, the alkaline earth metal is selected from the group consisting of Be, Sr, Ba, Ca and Mg, the Group 3A semimetal is the group consisting of Sc, Y, La and Ac Group 3B semimetal is selected from the group consisting of B, Al and Ga, the Group 4A semimetal is selected from the group consisting of Ti, Zr and Hf, the Group 4B semimetal is Si, Ge and It is selected from the group consisting of Sn, the Group 5A element is selected from the group consisting of V, Nb and Ta, the Group 5B element is selected from the group consisting of P, Sb and Bi, the lanthanum-based element is Ce, Pr , Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, wherein the actinium-based elements are Th, U, Nb, Pu, and their groups An anode active material comprising an element selected from the group consisting of a sum. The anode active material according to claim 5, wherein the metal-containing carbon modifying element is contained in an amount of 1 to 90% by weight based on the composite including the entire carbon element-metal-containing carbon modifying element. The method of claim 5, wherein the carbonaceous material is natural graphite, artificial graphite, crystalline carbon of graphite carbon fiber; Amorphous carbon obtained by treating a carbon raw material selected from the group consisting of solid carbon, petroleum, coal based carbon raw materials, resin based carbon, and combinations thereof; And a combination selected from the group consisting of a negative electrode active material. The mixture of claim 5, wherein the carbonaceous material is a carbonaceous precursor and a carbon modified element precursor mixture. An anode active material, characterized in that it is used in 1 to 1000 parts by weight based on 100 parts by weight. Iii) mixing a precursor comprising a carbon precursor and a metal containing carbon modifying element; Ii) first heat treating the obtained precursor mixture; And Iii) a second heat treatment of the heat treated mixture in a non-oxidizing atmosphere Method for producing a negative electrode active material for a lithium secondary battery comprising a carbon-metal-containing carbon modifying element comprising a. 12. The method of claim 11, wherein the carbon precursor is any one selected from solid carbon or liquid carbon. The method of claim 11, wherein the precursor containing the metal-containing carbon-modifying element is a transition metal, alkali metal, alkaline earth metal, Group 3A, 3B, 4A and 4B semimetals, Group 5A, 5B, lanthanum series or actinium A method for producing a negative electrode active material, characterized in that it is one type selected from the group consisting of alkoxides, salts, oxides, sulfides, hydroxides and hydrides containing at least one of the series elements. The method of claim 11, wherein the first heat treatment is performed at 150 to 300 ℃. The method of claim 11, wherein the first heat treatment is performed under an oxidizing atmosphere. 12. The method of claim 11, wherein the second heat treatment is performed at 500 to 1300 ° C. 12. The method of claim 11, wherein the second heat treatment is performed under a reducing atmosphere. Iii) mixing a precursor comprising a carbon precursor and a metal containing carbon modifying element; Ii) applying the carbonaceous material to the precursor mixture obtained above so that the precursor mixture is coated on the surface of the carbonaceous material; Iii) first heat treatment of the precursor mixture obtained above; And Iii) a second heat treatment of the mixture heat treated in a non-oxidizing atmosphere Including, a method of manufacturing a negative electrode active material for a lithium secondary battery coated with a composite comprising a carbon-based material and a carbon-containing carbon modifying element on the surface of the carbon-based material. 19. The method of claim 18, wherein the carbon precursor is any one selected from solid carbon or liquid carbon. 19. The method of claim 18, wherein the precursor containing the metal-containing carbon modifying element is a transition metal, an alkali metal, an alkaline earth metal, a Group 3A, 3B, 4A and 4B semimetal, Group 5A, 5B, lanthanide series or actinium. A method for producing a negative electrode active material, characterized in that it is one type selected from the group consisting of alkoxides, salts, oxides, sulfides, hydroxides and hydrides containing at least one of the series elements. The method of claim 18, wherein the first heat treatment is performed at 150 to 300 ℃. The method of claim 18, wherein the first heat treatment is performed under an oxidizing atmosphere. The method of claim 18, wherein the second heat treatment is performed at 500 to 1300 ℃. The method of claim 18, wherein the second heat treatment is performed under a reducing atmosphere. A negative electrode comprising the negative electrode active material according to any one of claims 1 to 10; A positive electrode including a positive electrode active material capable of reversible intercalation / deintercalation of lithium; And Lithium secondary battery comprising an electrolyte existing between the negative electrode and the positive electrode.

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