KR20160028192A - Method for manufacturing Co-Sb intermetallic compound/carbon nanocomposite using disproportionation reaction, nanocomposite manufactured thereby, and lithium secondary battery including the nanocomposite - Google Patents

Abstract

The present invention relates to a method for producing a cobalt-stibium intermetallic compound/carbon nanocomplex by using disproportionation reaction, a nanocomplex produced by the same, and a lithium secondary battery including the same. The method for producing a cobalt (Co)-stibium (Sb) intermetallic compound/carbon nanocomplex by using disproportionation reaction includes the following steps: (a) producing a Co-Sb intermetallic compound by using Co powder and Sb powder; and (b) producing the Co-Sb intermetallic compound/carbon nanocomplex including the Co-Sb intermetallic compound, amorphous Sb (a-Sb), and carbon by making the Co-Sb intermetallic compound react with carbon (C). The nanocomplex is used as a negative electrode material for a secondary battery, particularly a lithium secondary battery to provide high capacity compared to an existing negative material and can have excellent cycle properties and enhance high rate properties.

Description

TECHNICAL FIELD The present invention relates to a method for producing a cobalt-antimony intermetallic compound / carbon nanocomposite using a disproportionation reaction, a nanocomposite prepared thereby, and a lithium secondary battery comprising the same , and lithium secondary battery including the nanocomposite}

More particularly, the present invention relates to a method for producing a cobalt-antimony intermetallic compound / carbon nanocomposite using a disproportionation reaction, a nanocomposite prepared thereby, To a lithium secondary battery.

The depletion of fossil fuels and the development of alternative energy sources due to environmental pollution are urgent and important. In addition, with the advent of hybrid vehicles and the rapid development of portable wireless information communication devices such as mobile phones and notebook computers, the importance of secondary batteries as portable power sources has been highlighted.

Particularly, the lithium secondary battery has advantages of high output and high energy compared to other secondary batteries, and can be used not only as a small power source for portable electronic devices such as a cell phone, a notebook, a digital camera, a camcorder, but also a hybrid car, -bike) and the like, and has been attracting much attention as a portable power source having a high energy density.

In order to improve the capacity and the operating voltage of the lithium secondary battery, research and development on the design of the electrode and the battery have been progressing actively. Particularly, in order to improve the performance of the lithium secondary battery, Is being actively studied.

In this regard, lithium metal (3860 mAh / g) was initially used as the negative electrode active material constituting the negative electrode of the lithium secondary battery. However, since lithium has a problem of low reversibility and low safety, carbon materials are mainly used as an anode active material of a lithium secondary battery.

The carbon anode material has a smaller capacity (372 mAh / g) than lithium metal, but has less volume change, excellent reversibility, and advantageous in terms of price. However, as the use of lithium secondary batteries increases, the demand for high capacity lithium secondary batteries is gradually increasing. Accordingly, researches on high capacity negative electrode active materials that can replace carbon materials are required.

 For example, silicon (Si, 4197 mAh / g), tin (Sn, 993 mAh / g), and tantalum Antimony (Sb, 660 mAh / g) and the like as an anode active material.

However, the lithium alloy material is subject to a volume change due to a phase change at the time of charging and discharging, and thus the generated stress causes a breakdown of the active material, thereby causing a great reduction in the capacity depending on the cycle.

Therefore, in order to improve the cycle characteristics, a technique of suppressing the expansion of the alloy by forming an alloy containing Si, Sn and Sb has been considered. However, when the alloy is used in this manner, the life characteristics and the effect of preventing the bulge expansion are somewhat improved as compared with the case where only the metal itself is used as the negative active material. However, due to the stress caused by the volume expansion occurring when alloying with lithium, There is a problem in that it is not enough to use it.

It has also been proposed to use nano-sized powders as an alternative to minimize volume changes. However, conventionally, nano-sized powders have been produced by using complex chemical methods such as reduction method and coprecipitation method, and the initial efficiency is very low due to irreversible side reactions caused by the salts left in the chemical process .

Furthermore, the nano powders thus produced also undergo coagulation phenomenon during charging and discharging, resulting in coarsening of the particles, resulting in a volume change, which is accompanied by a disadvantage that rapid capacity reduction is caused by the cycle .

 C.-M. Park, J.-H. Kim, H. Kim and H.-J. Sohn, Chem. Soc. Rev., 2010, 39, 3115.  J. Wang, I. D. Raistrick and R. A. Huggins, J. Electrochem. Soc., 1986, 133, 457.  M.-S. Park, S. A. Needham, G.-X. Wang, Y.-M. Kang, J.-S. Park, S.-X. Dou and H.-K. Liu, Chem. Mater., 2007, 19, 2406.

In order to solve the above problems, the present invention provides a method for manufacturing a nanocomposite, which can be used as a negative electrode material of a lithium secondary battery and can greatly improve a high rate characteristic and a cycle life while maintaining a high capacity, And a lithium secondary battery comprising the nanocomposite.

It is another object of the present invention to provide a method for producing nanocomposite easily and efficiently without using complicated and ineffective processes such as chemical methods by applying a new synthesis method of an alloy and a disproportionation reaction method.

According to an aspect of the present invention, there is provided a method of manufacturing a Co-Sb intermetallic compound, comprising: (a) preparing a cobalt-antimony intermetallic compound using cobalt powder (Co) and antimony (Sb) powder; And (b) reacting the cobalt-antimony intermetallic compound with carbon (C) to form a cobalt-antimony intermetallic compound, an amorphous antimony (a-Sb) Antimony intermetallic compounds / carbon nanocomposites using a disproportionation reaction, which comprises the step of preparing an intermediate compound / carbon nanocomposite.

Further, in the step (a), the cobalt-antimony intermetallic compound is prepared by mixing cobalt powder (Co) and antimony (Sb) powder, followed by high energy mechanical milling (HEMM) Antimony intermetallic compound / carbon nanocomposite using a disproportionation reaction.

The high energy mechanical milling is also carried out by attrition milling, shaker milling or planetary ball milling. The cobalt-antimony metal using a disproportionation reaction is characterized in that the high energy mechanical milling is carried out by attrition milling, shaker milling or planetary ball milling. Intercalation compound / carbon nanocomposite.

Also, the present invention proposes a method for producing a cobalt-antimony intermetallic compound / carbon nanocomposite using disproportionation, wherein the cobalt-antimony intermetallic compound produced in step (a) is CoSb ₂ or CoSb ₃ .

In addition, in the step (b), the nanocomposite is prepared by mixing the cobalt-antimony intermetallic compound with carbon and then performing high energy mechanical milling (HEMM) Cobalt-antimony intermetallic compounds / carbon nanocomposites.

The high energy mechanical milling is also carried out by attrition milling, shaker milling or planetary ball milling. The cobalt-antimony metal using a disproportionation reaction is characterized in that the high energy mechanical milling is carried out by attrition milling, shaker milling or planetary ball milling. Intercalation compound / carbon nanocomposite.

Further, it is characterized in that the nanocomposite is produced by mixing 30 wt% or more and less than 100 wt% of cobalt-antimony intermetallic compound and 0 wt% or more of carbon, and then performing high energy mechanical milling (HEMM) Antimony intermetallic compound / carbon nanocomposite using a disproportionation reaction.

Antimony intermetallic compound / carbon nanocomposite using a disproportionation reaction characterized in that a disproportionation reaction takes place in the step (b) according to the following reaction formula:

[Reaction Scheme]

CoSb _X + C? CoSb _X-1 + Sb (amorphous) + C

(Wherein X is 2 or 3).

The carbon may be one selected from the group consisting of acetylene black, Super P black, carbon black, Denka black, activated carbon, graphite, hard carbon and soft carbon Antimony intermetallic compound / carbon nanocomposite using a disproportionation reaction, wherein the cobalt-antimony intermetallic compound / carbon nanocomposite is prepared by a disproportionation reaction.

The present invention also provides a process for producing a cobalt-antimony intermetallic compound / carbon nanocomposite using a disproportionation reaction, wherein the cobalt-antimony intermetallic compound / carbon nanocomposite is a powder having an average diameter of 1 nm or more and less than 500 μm do.

Also, the present invention proposes a method for producing a cobalt-antimony intermetallic compound / carbon nanocomposite using a disproportionation reaction, wherein the cobalt-antimony intermetallic compound grains contained in the nanocomposite have an average diameter of less than 50 nm.

The present invention also provides a secondary battery comprising the cobalt-antimony intermetallic compound / carbon nanocomposite prepared by the above production method as a negative electrode active material.

Further, the secondary battery is a secondary battery characterized in that lithium is a secondary battery.

According to the present invention, a nano-sized composite can be produced simply and efficiently without a complicated and ineffective process such as a chemical method by a new method of alloying and disproportionation reaction. In addition, the nanocomposite is used as a negative electrode material of a lithium secondary battery, and unlike conventional negative electrode materials, the nanocomposite does not have a problem of volumetric change due to grain coarsening while maintaining a high capacity, and the lithium secondary battery using the composite has a high Characteristics can be achieved, and the cycle life can be greatly improved.

Figure 1 is a schematic diagram of a nanoscale composite material comprising a cobalt-antimony intermetallic compound (CoSb _x x = 1 or 2), amorphous antimony (a-Sb) and carbon (C) through alloying and disproportionation processes in accordance with the present invention (CoSb _x / Sb / C).
Figure 2a is a cobalt-antimony phase diagram of a binary system (CoSb), the Figure 2b, Figure 2c and 2d, respectively CoSb, CoSb _2, and Fig. ₃ is a graph showing the results of x-ray diffraction analysis for CoSb ₃ .
3A and 3B are graphs showing X-ray diffraction analysis results of the nanocomposite (CoSb ₂ / C) prepared in Example 1 and the nanocomposite (CoSb ₃ / C) prepared in Example 2, respectively.
4A and 4B are transmission electron micrographs of the nanocomposite (CoSb ₂ / C) prepared in Example 1 and the nanocomposite (CoSb ₃ / C) prepared in Example 2, respectively.
FIG. 5 is a graph showing cycle characteristic data for CoSb, CoSb ₂ , CoSb ₃ cobalt antimony intermetallic compounds and a secondary battery using antimony (Sb) as a negative electrode material as a comparative example.
Figure 6a and 6b claim 1, 2, 5, 10 in the case of using the nanocomposite (CoSb ₃ / C) produced in each embodiment the nanocomposite prepared in 1 (CoSb ₂ / C) and Example 2, 50, and 100 cycles, respectively.
7 is for a secondary battery using the tin (Sb), as a comparative example and the first embodiment of the nanocomposite (CoSb ₂ / C) and carrying out the nanocomposite (CoSb ₃ / C) prepared in Example 2 produced in the cathode material Cycle characteristic data.
8 is a graph showing high-rate characteristic data for a secondary battery using a nanocomposite (CoSb ₂ / C) prepared in Example 1 and a commercially available graphite (MCMB: Meso carbon Micro Beads) Graph.

In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

Embodiments in accordance with the concepts of the present invention can make various changes and have various forms, so that specific embodiments are illustrated in the drawings and described in detail in this specification or application. It should be understood, however, that the embodiments according to the concepts of the present invention are not intended to be limited to any particular mode of disclosure, but rather all variations, equivalents, and alternatives falling within the spirit and scope of the present invention.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms "comprises ",or" having ", or the like, specify that there is a stated feature, number, step, operation, , Steps, operations, components, parts, or combinations thereof, as a matter of principle.

Hereinafter, a method for producing a cobalt-antimony intermetallic compound / carbon nanocomposite using a disproportionation reaction according to the present invention, a nanocomposite prepared thereby, and a lithium secondary battery comprising the same will be described in detail.

The method for producing a cobalt-antimony intermetallic compound / carbon nanocomposite according to the present invention comprises the steps of: (a) preparing a cobalt-antimony intermetallic compound using cobalt powder (Co) and antimony (Sb) step; And (b) reacting the cobalt-antimony intermetallic compound with carbon (C) to form a cobalt-antimony intermetallic compound, an amorphous antimony (a-Sb) To produce an intercalated compound / carbon nanocomposite.

The step (a) is a step of preparing a cobalt-antimony intermetallic compound by using cobalt and antimony as a starting material, and a cobalt-antimony intermetallic compound such as CoSb ₂ or CoSb ₃ is produced through this step, antimony intermetallic compound / carbon nanocomposite through a disproportionation reaction in step (b).

The specific method for carrying out this step is not particularly limited, but a high-energy mechanical milling (high-energy mechanical milling) capable of atomizing the powder by maximizing the diffusing power between powders as well as atomizing the powder by adding high- high energy mechanical milling (HEMM) to produce cobalt-antimony intermetallic compounds.

When high energy mechanical milling, such as attrition milling, shaker milling or planetary ball milling, is used, the mixed powder may be repeated between the milling balls or between the milling balls and the milling vessel Alloying takes place through a process in which cold pressure welding takes place after fractured and deformed by impact.

 The milling process conditions such as the milling speed and the milling time depend on the kind and amount of the raw material powder. However, those skilled in the art can sufficiently induce the plastic deformation and diffusion of the powder to achieve the desired reaction, It is possible to easily adopt appropriate process conditions that do not cause problems such as contamination of the powder and economical efficiency without excessive trial and error. For example, in the present invention, according to the milling speed of 500 rpm or more and the milling time of 1 to 24 hours This step can be carried out.

The high-energy mechanical milling in this step is preferably performed in an inert gas atmosphere such as argon (Ar) in order to prevent oxidation or contamination of the powder.

On the other hand, after performing the high-energy mechanical milling, heat treatment may be performed at 800 to 1000 ° C, if necessary.

Next, in step (b), the nanocomposite is prepared by reacting the cobalt-antimony intermetallic compound prepared in the previous step with carbon.

Specifically, in this step, a cobalt-antimony intermetallic compound such as CoSb ₂ or CoSb _{3 is} mixed with carbon, followed by attrition milling, shaker milling, planetary ball milling, To produce a cobalt-antimony intermetallic compound / carbon nanocomposite comprising a cobalt-antimony intermetallic compound, amorphous antimony (a-Sb) and carbon.

Notably, in the present step, the cobalt, as schematically shown in Figure 1 - antimony intermetallic compound (CoSb _X) and the carbon in the course of the reaction, an amorphous antimony (Sb-a) as shown in Scheme 1 below and CoSb _X- disproportionation reaction to produce ₁ (disproportionation reaction) is that it takes place.

[Reaction Scheme 1]

CoSb _X + C? CoSb _X-1 + Sb (amorphous) + C

For example, CoSb ₂ through the disproportionation reaction may include CoSb and amorphous antimony (a-Sb) as shown in the following reaction formula 2, CoSb ₃ and CoSb ₂ and amorphous antimony (a-Sb) .

[Reaction Scheme 2]

CoSb ₂ + C? CoSb + Sb (amorphous) + C

[Reaction Scheme 3]

CoSb ₃ + C? CoSb ₂ + Sb (amorphous) + C

As described above, when a binary alloy is reacted with carbon through high-energy mechanical milling to generate a disproportionation reaction, a simple and efficient cobalt-antimony intermetallic compound, an amorphous antimony (a-Sb ) And carbon can be prepared. For reference, amorphous antimony that reacts with lithium is generally known to exhibit excellent capacity and cycle characteristics as a lithium secondary battery cathode material.

Meanwhile, in carrying out this step, it is preferable to carry out high-energy mechanical milling after mixing 30 wt% to less than 100 wt% of the cobalt-antimony intermetallic compound and 0 wt% to 70 wt% or less of carbon, -Antimony intermetallic compound powder is contained in an amount less than 30 wt%, that is, when the carbon component powder is contained in an amount exceeding 70 wt%, the carbon component is excessively ball milled. In this case, the secondary battery And the discharge capacity and efficiency are deteriorated, resulting in a decrease in the overall capacity and efficiency.

The milling process conditions such as the milling speed and the milling time depend on the kind and amount of the raw material powder, but those skilled in the art can sufficiently effect plastic deformation and diffusion of the powder to achieve the desired reaction, It is possible to easily adopt appropriate process conditions that do not cause problems such as contamination, powder contamination and economical deterioration without undue trial and error. For example, in the present invention, a milling time of 1 to 20 hours This step can be carried out in accordance with

The high-energy mechanical milling in this step is preferably performed in an inert gas atmosphere such as argon (Ar) in order to prevent oxidation or contamination of the powder.

On the other hand, as the carbon component provided in this step, any one of acetylene black, super P black, carbon black, Denka black, activated carbon, graphite, hard carbon or soft carbon is used Among them, it is more preferable to use a carbon component having a nano-size such as super P black. These carbon components are not reactive with metals, increasing the conductivity and preventing aggregation.

The cobalt-antimony intermetallic compound / carbon nanocomposite produced through this step may be a powder having an average diameter of 1 nm or more and less than 500 μm, and the cobalt-antimony intermetallic compound grains contained in the nanocomposite may have an average diameter Lt; / RTI >

Next, a secondary battery comprising the nanocomposite prepared by the method of manufacturing a cobalt-antimony intermetallic compound / carbon nanocomposite using the disproportionation as described above as a negative electrode active material, particularly a lithium secondary battery, Will be described in detail.

The lithium secondary battery including the nanocomposite according to the present invention as a negative electrode active material includes a cathode, a cathode, a separator, and an electrolyte, wherein the cathode includes the above-described cobalt-antimony intermetallic compound / carbon nanocomposite as an active material do.

At this time, the lithium secondary battery can be suitably used without any limitations in configurations known in the art except for the negative electrode active material.

For example, the anode may be reversibly doped with lithium, such as LiCoO ₂ , LiMn ₂ O ₄ , LiNi _1/3 Co _1/3 Mn _1/3 O ₂ , LiFeO ₄ , LiNiVO ₄ , LiNi _1/2 Mn _1/2 O ₂ , A positive electrode active material, a conductive material, and a binder, which are compounds capable of intercalating and deintercalating lithium ions.

As the separator, a polyolefin-based porous film such as polyethylene (PE) or polypropylene (PP) can be used.

Examples of the electrolyte include propylene carbonate (PC), ethylene carbonate (EC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), butylene carbonate, benzonitrile, acetonitrile, tetrahydrofuran, , Dioxolane, 4-methyldioxolane, N, N-dimethylformamide, dimethylacetoamide, dimethylsulfoxide, dioxane, 1,2-dimethoxyethane, sulfolane, dichloroethane, chlorobenzene, nitrobenzene, di A solvent in which two or more solvents selected from ethyl carbonate, methyl propyl carbonate, methyl isopropyl carbonate, ethyl butyl carbonate, dipropyl carbonate, diisopropyl carbonate, dibutyl carbonate, diethyleneglycol, _{6, LiCF 3 SO 3, Li} (CF 3 SO 2) 2, LiBF 4, LiClO 4, LiN (SO 2 C 2 F 5) using the electrolytic solution having a lithium salt dissolved in the _second place, or Polyethylene oxide, polypropylene oxide, was impregnated to the electrolyte to a solid electrolyte made of a high ionic conductivity for the lithium ion polymer such as polyethyleneimine can be used in a gel form.

Furthermore, it is needless to say that the lithium secondary battery according to the present invention may have various shapes depending on its use such as a cylindrical shape, a square shape, a coin shape, or a pouch shape.

Hereinafter, the present invention will be described in detail on the basis of embodiments. The presented embodiments are illustrative and are not intended to limit the scope of the invention.

Example 1 Manufacture of Nanocomposite Containing Cobalt-Antimony Intermetallic Compound (CoSb), Amorphous Antimony (a-Sb) and Carbon

Antimony intermetallic compound (CoSb) is produced by causing a disproportionation reaction to a cobalt-antimony intermetallic compound by reacting it with carbon after preparing a cobalt-antimony intermetallic compound as described below, Antimony intermetallic compound / carbon nanocomposite comprising amorphous antimony (a-Sb) and carbon was prepared.

(1) Preparation of cobalt-antimony intermetallic compound

Cobalt (Co) powders having a particle size of 100 mesh or less and commercially available antimony (Sb) powders having an average particle size of 100 mesh were mixed at a molar ratio of 1: 2, and then a diameter of 5.5 cm and a height of 9 cm Was loaded into a cylindrical vial of SKD11 material with a 3/8 inch ball, mounted on a vibrating mill, and then subjected to mechanical synthesis for 1 hour at 700 revolutions per minute.

At this time, the weight ratio of the balls to the powder was maintained at 20: 1, and mechanical synthesis was prepared in a glove box of argon gas atmosphere in order to suppress the influence of oxygen and water as much as possible.

The mechanical synthesis is performed for 1 hour, and then the ball milled powder is heat-treated at 800 to 1000 ° C. It proceeds in an argon gas atmosphere to minimize oxygen and moisture effects.

After the mechanical synthesis and the heat treatment, cobalt-antimony intermetallic compound (CoSb ₂ ) was formed.

(2) Production of nanocomposite comprising cobalt-antimony intermetallic compound (CoSb), amorphous antimony (a-Sb) and carbon

The cobalt-antimony intermetallic compound (CoSb ₂ ) and the super P powder synthesized in the above (1) were mixed at a mass ratio of 60:40. Then, a cylindrical vial having a diameter of 5.5 cm and a height of 9 cm was inserted into a cylindrical vial / 8 inch size balls, mounted on a vibrating mill, and then subjected to mechanical synthesis at a rotation speed of 700 revolutions per minute.

At this time, the weight ratio between balls and powder was maintained at 20: 1, and mechanical synthesis was prepared in a glove box of argon gas atmosphere in order to suppress the influence of oxygen and moisture as much as possible.

The mechanical synthesis was performed for 12 hours to form a nanoscale complex containing a cobalt-antimony intermetallic compound (CoSb), amorphous antimony (a-Sb) and carbon components.

Example 2 Cobalt-antimony intermetallic compound (CoSb ₂ ), Amorphous antimony (a-Sb), and carbon.

In this embodiment, CoSb ₃ is formed as a cobalt-antimony intermetallic compound by using cobalt powder and antimony powder at a molar ratio of 1: 3 in the preparation of a cobalt-antimony intermetallic compound in step (1) (CoSb ₂ ), amorphous antimony (a-Sb), and carbon components were prepared through the same processes as in Example 1-1 except that the cobalt-antimony intermetallic compound (CoSb ₂ ), amorphous antimony

<Experimental Examples> Characteristic analysis of the nanocomposite prepared in Examples 1 and 2 and observation of characteristics of the lithium secondary battery including the nanocomposite as a negative electrode active material

FIG. 2A is a binary phase diagram of cobalt and antimony, showing that there are three types of cobalt antimony intermetallic compounds: CoSb, CoSb ₂ and CoSb ₃ .

FIGS. 2B, 2C and 2D are graphs showing the results of x-ray diffraction analysis for CoSb, CoSb ₂ and CoSb ₃ , respectively.

3A and 3B are graphs showing X-ray diffraction analysis results of the nanocomposite (CoSb ₂ / C) prepared in Example 1 and the nanocomposite (CoSb ₃ / C) prepared in Example 2, respectively. 3A and 3B, it can be seen that CoSb ₂ becomes CoSb and amorphous antimony (a-Sb) by the disproportionation reaction in FIG. Amorphous antimony (a-Sb) does not appear in X-ray diffraction analysis. Also, in FIG. 3B, it can be seen that CoSb ₃ is changed into CoSb ₂ and amorphous Sb due to the disproportionation reaction.

4A and 4B are transmission electron micrographs of the nanocomposite (CoSb ₂ / C) prepared in Example 1 and the nanocomposite (CoSb ₃ / C) prepared in Example 2, respectively.

Referring to (1) of FIG. 4A, it can be seen that a nanocomposite having a size of about 100 to 300 nm is formed. Referring to (2) and (3), the nanocomposite has a cobalt-antimony as an amorphous antimony (a-Sb) this can be seen by the amorphous carbon (C) to that becomes mixed with the matrix well HR-TEM and FT patterns pictures, the nanocomposite prepared in example 1 of Fig. 3a (CoSb ₂ / C). The results of the X-ray diffraction analysis are shown in Fig. In (4), it can be confirmed that cobalt-antimony (CoSb), amorphous antimony (a-Sb) and amorphous carbon (C) are well dispersed.

Referring to (1) of FIG. 4, it can be seen that a nanocomposite having a size of about 100 to 300 nm is formed. Referring to (2) and (3), the nanocomposite has a cobalt-antimony ₂ ) It can be seen from the HR-TEM and FT patterns that the amorphous carbon (C) and the amorphous antimony (a-Sb) are mixed well as a matrix. (4), it can be confirmed that cobalt-antimony (CoSb ₂ ), amorphous antimony (a-Sb) and amorphous carbon (C) are well dispersed.

FIG. 5 is a graph showing cycle characteristic data for CoSb, CoSb ₂ , CoSb ₃ cobalt antimony intermetallic compounds and a secondary battery using antimony (Sb) as a negative electrode material as a comparative example.

CoSb, CoSb ₂ , CoSb _{3 The} above alloy has some improvement in life characteristics and prevention of volume expansion, as compared with the case of using only antimony (Sb) metal itself. However, it can be seen that the capacity decreases due to charging and discharging due to the stress caused by the volume expansion occurring when alloying with lithium.

Figure 6a and 6b claim 1, 2, 5, 10 in the case of using the nanocomposite (CoSb ₃ / C) produced in each embodiment the nanocomposite prepared in 1 (CoSb ₂ / C) and Example 2, 50, and 100 cycles, respectively.

7 is for a secondary battery using the tin (Sb), as a comparative example and the first embodiment of the nanocomposite (CoSb ₂ / C) and carrying out the nanocomposite (CoSb ₃ / C) prepared in Example 2 produced in the cathode material Cycle characteristic data.

In case of CoSb ₃ / C, the capacity gradually decreases due to the volume expansion due to charging and discharging. However, in case of CoSb ₂ / C, the capacity of 500 mAh / g or more is maintained up to 100 cycles.

8 is a graph showing high-rate characteristic data for a secondary battery using a nanocomposite (CoSb ₂ / C) prepared in Example 1 and a commercially available graphite (MCMB: Meso carbon Micro Beads) Graph.

Claims (13)

(a) preparing a cobalt-antimony intermetallic compound using cobalt powder (Co) and antimony (Sb) powder; And
(b) reacting the cobalt-antimony intermetallic compound with carbon to form a cobalt-antimony intermetallic compound comprising a cobalt-antimony intermetallic compound, an amorphous antimony (a-Sb) Antimony intermetallic compound / carbon nanocomposite using a disproportionation reaction, comprising the step of preparing a compound / carbon nanocomposite. The method according to claim 1,
The cobalt-antimony intermetallic compound is prepared by mixing cobalt powder (Co) and antimony (Sb) powder in the step (a), followed by high energy mechanical milling (HEMM) and heat treatment Antimony intermetallic compound / carbon nanocomposite using a disproportionation reaction. 3. The method of claim 2,
Characterized in that the high energy mechanical milling is carried out by attrition milling, shaker milling or planetary ball milling, characterized in that the cobalt-antimony intermetallic compound (Method for producing carbon nanocomposite). The method according to claim 1,
Wherein the cobalt-antimony intermetallic compound produced in the step (a) is CoSb ₂ or CoSb ₃ , wherein the cobalt-antimony intermetallic compound is CoSb ₂ or CoSb ₃ . The method according to claim 1,
Wherein the cobalt-antimony intermetallic compound is mixed with carbon and the nanocomposite is prepared by high energy mechanical milling (HEMM) in the step (b) Antimony intermetallic compound / carbon nanocomposite. 6. The method of claim 5,
Characterized in that the high energy mechanical milling is carried out by attrition milling, shaker milling or planetary ball milling, characterized in that the cobalt-antimony intermetallic compound (Method for producing carbon nanocomposite). 6. The method of claim 5,
Characterized in that the nanocomposite is produced by mixing 30 wt% to less than 100 wt% of cobalt-antimony intermetallic compound and 0 wt% to 70 wt% or less of carbon and then through high energy mechanical milling (HEMM) , A method for producing a cobalt-antimony intermetallic compound / carbon nanocomposite using a disproportionation reaction. The method according to claim 1,
Antimony intermetallic compound / carbon nanocomposite using a disproportionation reaction, wherein a disproportionation reaction takes place in the step (b) according to the following reaction formula.
[Reaction Scheme]
CoSb _X + C? CoSb _X-1 + Sb (amorphous) + C
(Wherein X is 2 or 3). The method according to claim 1,
The carbon may be at least one selected from the group consisting of acetylene black, Super P black, carbon black, Denka black, activated carbon, graphite, hard carbon and soft carbon. Antimony intermetallic compound / carbon nanocomposite using a disproportionation reaction. The method according to claim 1,
Wherein the cobalt-antimony intermetallic compound / carbon nanocomposite is a powder having an average diameter of 1 nm or more and less than 500 占 퐉, wherein the cobalt-antimony intermetallic compound / carbon nanocomposite is a powder having an average diameter of 1 nm or more and less than 500 占 퐉. 11. The method of claim 10,
Wherein the cobalt-antimony intermetallic compound grains contained in the nanocomposite have an average diameter of less than 50 nm. The method of claim 1, wherein the cobalt-antimony intermetallic compound grains have an average diameter of less than 50 nm. A secondary battery comprising a cobalt-antimony intermetallic compound / carbon nanocomposite prepared by the method of any one of claims 1 to 10 as an anode active material. 13. The method of claim 12,
Wherein the secondary battery is lithium secondary battery.

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