KR20120045684A - Development of the Ultrahigh Power Lithium Ion Battery Anode Material Using Dynamically Size Transformable Metal Oxides-Carbon Nanostructure Composites - Google Patents

Abstract

The present invention comprises the steps of adding an ultra-high power lithium-ion secondary battery negative electrode composition and (a) carbon nanostructure to the ethylene glycol solution using an oxide carbon nanocomposite capable of size dynamic transition and then dispersing by ultrasonic wave; (b) adding an Ethylene Glycol solution in which a transition metal precursor is dissolved, and adding 1M aqueous NaOH solution as a reducing agent; (c) reducing the metal salt by heating in a microwave oven for 60 to 120 seconds, and then centrifuging the dispersion at 6000 to 8000 rpm for 10 to 20 minutes; (d) after the centrifugation and vacuum-dried at 50 ~ 70 ℃, heat treatment in a 250 ~ 350 ℃ hydrogen atmosphere, heat treatment in 200 ℃ air atmosphere to prepare an oxide-carbon nanocomposite hybrid material; oxide comprising a (Oxide) Carbon (Carbon) relates to a method for producing a lithium ion secondary battery negative electrode composition, characterized in that using the nanocomposite.
The present invention reduced the size of the nano-sized particles during the adsorption / desorption of lithium, which can demonstrate the phenomenon of increased capacity and reaction rate, higher capacity than when only pure transition metal oxides or carbon nanostructures are present. Since it exists as a small metal, it is possible to implement a high power cathode, so that the industrial applicability is very high.

Description

Development of the Ultrahigh Power Lithium Ion Battery Anode Material Using Dynamically Size Transformable Metal Oxides-Carbon Nanostructure Composites}

The present invention relates to a lithium ion secondary battery negative electrode composition. More particularly, the present invention relates to a lithium ion secondary battery negative electrode composition and a method of manufacturing the same, characterized in that the oxide (Carbon) nanocomposite is used.

As the weight reduction and high functionality of portable wireless devices such as video cameras, portable telephones, and portable PCs have progressed, much research has been conducted on secondary batteries used as driving power sources. The secondary batteries that have been developed so far are about 10 types, but the most used ones are nickel cadmium batteries, nickel hydrogen batteries, nickel zinc batteries, and lithium ion secondary batteries. Among them, lithium secondary batteries are attracting the most attention as next generation power sources due to their excellent characteristics such as long life and high capacity.

The research and development of lithium secondary batteries began in the early 1970s, and research institutes around the world are fiercely competing for development. Sony Energy Tech Co., Ltd. has developed a lithium ion secondary battery composed of a lithium positive electrode using a cobalt oxide active material and a carbon material negative electrode, and Molly Energy has commercialized a lithium metal secondary battery using lithium metal as a negative electrode using a nickel oxide active material.

In general, controlling the size of particles is a very important technique for various industrial aspects. Metal oxide is used as a negative electrode material in lithium ion battery, but its capacity is high but its reaction rate is not high so it is not suitable for high output battery. Therefore, it is an object of the present invention to overcome this problem and develop an ultra-high power lithium ion secondary battery negative electrode material using an oxide carbon nanocomposite capable of size dynamic transition.

In order to solve the above problems, the present invention provides a lithium ion secondary battery negative electrode composition, wherein an oxide (carbon) nanocomposite is used in a lithium ion secondary battery negative electrode composition.

The oxide carbon nanocomposite may be characterized in that size dynamic transition is possible.

In addition, the present invention (a) adding a carbon nanostructure to the Etylene Glycol solution and then dispersing by using ultrasonic waves; (b) adding an Ethylene Glycol solution in which a transition metal precursor is dissolved, and adding 1M aqueous NaOH solution as a reducing agent; (c) reducing the metal salt by heating in a microwave oven for 60 to 120 seconds, and then centrifuging the dispersion at 6000 to 8000 rpm for 10 to 20 minutes; (d) after vacuum drying at 50-70 ° C. after the centrifugation, heat-treating at 250-350 ° C. hydrogen atmosphere, and heat-treating at 200 ° C. in an air atmosphere. It provides a method for producing an ion secondary battery negative electrode composition.

The carbon nanostructure may be any one selected from the group consisting of nanotubes (CNT), graphene (Graphene) and carbon nanoribbon (carbon nanoribbon).

The transition metal is Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Lr, Rf, Db, Sg, Bh, Hs, Mt, Ds, Rg and Cn may be any one selected from the group consisting of.

Preferably, the oxide-carbon nanocomposite hybrid material is mixed with polyvinylidene fluoride (PVDF) in a weight ratio of 9: 1, and then placed in an N-Methyl-2-pyrrolidone (NMP) solution, followed by sonication and stirring to repeat the oxide-carbon nanocomposite paste. It may further comprise the step of preparing.

The present invention relates to the development of a structure in which a metal oxide is dispersed in a carbon nanostructure, and the carbon nanostructure can be used as carbon nanotubes, graphene, carbon nanoribbons, etc .; Nitrogen is added as N ₂ Plasma, NH ₃ High temperature heat treatment of plasma, nitrogen atmosphere, etc. may be used; The oxide may be one or more of SnO ₂ , TiO ₂ , Fe ₃ O ₄ , Co ₃ O ₄ , NiO, MnO ₂ , MoO ₃ , WO _3, and the like.

The present invention reduced the size of the nano-sized particles during the adsorption / desorption of lithium, which can demonstrate the phenomenon of increased capacity and reaction rate, higher capacity than when only pure transition metal oxides or carbon nanostructures are present. Showed. Therefore, the presence of small metals made it possible to implement a high-output cathode.

Since the carbon nanostructure has a high electrical conductivity and a large specific surface area, the carbon nanostructure can serve as a support for forming nanoparticles and is electrochemically stable. Therefore, the advantageous effect that the technology of manufacturing a nano-sized metal oxide on the carbon nanostructure has a great advantage in producing a high-output negative electrode material. Furthermore, there is an advantageous effect that the electron transfer rate can be increased, and the reaction rate can be increased more efficiently by increasing the diffusion rate of lithium ions.

In addition, the metal oxide has an advantageous effect that the lithium ion is separated into a smaller size metal oxide through the adsorption / desorption process, the electrochemical properties are much better.

1 relates to x-ray photoelectron spectroscopy (XPS).
Figure 2 compares the capacity of NiO-CNT, CNT and NiO.
3 shows the results of experiments with the NiO-CNT electrode at a very high charge / discharge rate (? 500C).
4 is analyzed using a Transmission Electron Microscope (TEM).

The present invention relates to a lithium ion secondary battery negative electrode composition, wherein an oxide (carbon) nanocomposite is used in a lithium ion secondary battery negative electrode composition.

The oxide carbon nanocomposite may be characterized in that size dynamic transition is possible.

In another aspect, the present invention (a) adding the carbon nanostructure to the Etylene Glycol solution and dispersed using ultrasonic waves; (b) adding an Ethylene Glycol solution in which a transition metal precursor is dissolved, and adding 1M aqueous NaOH solution as a reducing agent; (c) reducing the metal salt by heating in a microwave oven for 60 to 120 seconds, and then centrifuging the dispersion at 6000 to 8000 rpm for 10 to 20 minutes; (d) after the vacuum drying at 50 ~ 70 ℃ after the centrifugation, heat treatment in a 250 ~ 350 ℃ hydrogen atmosphere, heat treatment in an air atmosphere of 200 ℃; lithium characterized in that using the oxide carbon nanocomposite comprising It relates to a method for producing an ion secondary battery negative electrode composition.

The carbon nanostructure may be any one selected from the group consisting of nanotubes (CNT), graphene (Graphene) and carbon nanoribbon (carbon nanoribbon).

The transition metal is Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Lr, Rf, Db, Sg, Bh, Hs, Mt, Ds, Rg and Cn may be any one selected from the group consisting of.

Preferably, the NiO-CNT hybrid material is mixed with PVDF (Polyvinylidene fluoride) in a weight ratio of 9: 1, and then placed in an N-Methyl-2-pyrrolidone (NMP) solution to repeat sonication and stirring to prepare a NiO-CNT paste. It may further include.

It will be described in detail based on the embodiment with reference to the drawings. However, these are for the purpose of illustrating the present invention in more detail, and the scope of the present invention is not limited thereto.

Example 1 Preparation of CNT

A catalyst for CNT growth was prepared by magnetron RF sputtering.

In this case, a SiO ₂ / Si substrate was used, and the deposition temperature was 200 ° C., and the pressure was deposited with cobalt (Co) at 15 Torr in an argon (Ar) atmosphere. During deposition, RF power was 100W and the thickness of iron deposition on the substrate was 10 nm.

In order to form the iron deposited on the substrate as catalyst particles, plasma treatment was performed for 1 minute at 600 W microwave power in a microwave enhanced CVD apparatus. It was.

When the cobalt particles are formed on the substrate, the substrate on which the cobalt particles are formed is placed in the chamber, and 20 sccm of methane (CH ₄ ) and 100 sccm of nitrogen (N ₂ ) are respectively supplied into the chamber, and a plasma reaction is performed to carry out a nitrogen reaction. Nanotubes were prepared.

At this time, the temperature in the chamber was maintained at 700 ℃, the pressure was 21 Torr (Torr) and the microwave power during the plasma reaction was carried out for 20 minutes at 600W.

As a result of analyzing the nitrogen content of the prepared carbon nanotubes using XPS was 2.98at% as shown in FIG. The concentration of nitrogen produced can be adjusted to 0-10 at%.

Example 2 Preparation of Graphene

Graphene oxide (GO) was first prepared by chemical oxidation. The oxidants used were sodium permanganate (KMnO ₄ ) and sodium nitrite (NaNO ₃ ), and concentrated sulfuric acid (95%) was used as a solvent. Add 2 g of Graphite, 1 g of sodium nitrite, and 46 ml of sulfuric acid into the flask, and slowly add 6 g of sodium permanganate. At this time, the whole container is in an ice bath and the temperature does not rise more than 10 degree during reaction. When all the sodium permanganate is injected, the solution is maintained for 2 hours in the temperature range of 32-38 ° C. Then slowly pour 90 ml of water so that the temperature does not exceed 95 ° C. The solution is allowed to react for 15 minutes while maintaining the temperature of 95 ° C. After the reaction, 280 ml of excess water was slowly poured again and 280 ml of warm 3% hydrogen peroxide solution was added.

Neutralize through the filtering process several times to neutralize the finished GO solution again. At this time, the filter is washed 5 times with 10% hydrochloric acid to remove excess metal particles. Neutral GO is again dissolved in water and ultrasonically dispersed. Put the GO solution dispersed by ultrasonic wave more than 30 minutes into Sentryfuge and run it for more than 15 minutes under the gravity of 10000g. After that, discard the unclean GO and choose a well-dispersed GO. The purified GO is dried again in a vacuum oven at 80 ℃.

Chemically synthesized GO was again reduced to prepare Graphene. Reagents used were hydrazine (H ₂ N ₂ ) and ammonia water (NH ₄ OH) to be used as reducing agents.

Purified GO is dispersed in water at a certain concentration. At this time, the dispersion concentration is 0.5mg / ml. To disperse the GO, add water and sonicate for 30 minutes to disperse the GO. 28 μl of ammonia water at a concentration of 28% is added to the GO thus dispersed. At this time, the pH of the solution is about 11. Hydrazine is added to the pH adjusted solution. The amount of hydrazine is 1/8 of GO. The solution is then heated to 100 ° C. while mixing with a magnetic spin bar and allowed to react for 1 hour. The graphene is filtered again to make it into a midline and then dried in a vacuum oven.

Example 3 Preparation of NiO-CNT Electrode

In this embodiment, carbon nanotubes (CNTs) were used as the carbon nanostructures.

5 mg of CNT was added to 50 ml of Etylene Glycol solution and dispersed using ultrasonic waves.

In this embodiment, Ni was used as an example of the transition metal, and 1 ml of 10 mM Ni (CH ₃ COO) ₂ / 4H ₂ O Ethylene Glycol solution was used. As a reducing agent, 0.5 ml of 1M NaOH aqueous solution was used.

After adding the metal salt and the reducing agent, the metal salt was reduced by heating in a microwave oven for 90 seconds, and then the dispersion was centrifuged at 7000 rpm for 15 minutes, dried in vacuo at 60 ° C., and then heat treated at 300 ° C. in a hydrogen atmosphere, at 200 ° C. in an air atmosphere. NiO-CNT hybrid materials were prepared by heat treatment.

Mix about 10 mg of NiO-CNT hybrid material with about 1.1 mg of Polyvinylidene fluoride (PVDF) (Weight 9: 1), add 15 drops of N-Methyl-2-pyrrolidone (NMP) solution, and repeat sonication and stirring. CNT paste was prepared.

Pellets were prepared to a thickness of 200 um on 18 um copper foil and dried overnight in an oven at 80 ° C.

The prepared electrode is placed in a glove box for half cell test to produce a half cell in which one electrode is a lithium foil.

Case-made electrode-membrane-gasket-electrolyte-lithium foil-spacer-spring-cap was prepared in the order of pressing with a presser.

The separator was a porous polypropylene membrane, and the electrolyte was LiPF ₆ in DC / EDC (1: 1).

For the half-cell test, the characteristics of the electrode were examined up to 0.001V / 3V while maintaining the current value on the jig.

After one half cell test, remove the half cell in the glove box, wash the electrode in acetonitrile for more than 2 hours, put it in acetone, remove it from the copper foil through sonication, and visually check the particle change by placing it on a TEM grid. (See FIG. 4).

Although the present invention has been described in connection with the specific embodiments of the present invention, it is to be understood that the present invention is not limited thereto. Those skilled in the art can change or modify the described embodiments without departing from the scope of the present invention, and such changes or modifications are within the scope of the present invention. In addition, the materials of each component described herein can be readily selected and substituted for various materials known to those skilled in the art. Those skilled in the art will also appreciate that some of the components described herein can be omitted without degrading performance or adding components to improve performance. In addition, those skilled in the art may change the order of the method steps described herein depending on the process environment or equipment. Therefore, the scope of the present invention should be determined by the appended claims and equivalents thereof, not by the embodiments described.

Since the carbon nanostructure has a high electrical conductivity and a large specific surface area, the carbon nanostructure can serve as a support for forming nanoparticles, and is electrochemically stable, and a technique of manufacturing nano-sized metal oxide on the carbon nanostructure has a high-output cathode. There is a great advantage in producing the material.

Furthermore, the electron transfer rate can be increased, and the reaction rate can be increased more efficiently by increasing the diffusion rate of lithium ions. These metal oxides are separated into smaller metal oxides as the lithium ions are subjected to adsorption / desorption. The chemical properties are much better.

The present invention reduced the size of the nano-sized particles during the adsorption / desorption of lithium, which can demonstrate the phenomenon of increased capacity and reaction rate, higher capacity than when only pure transition metal oxides or carbon nanostructures are present. Since it exists as a small metal, it is possible to implement a high power cathode, so that the industrial applicability is very high.

Claims (6)

In the lithium ion secondary battery negative electrode composition, a lithium ion secondary battery negative electrode composition comprising an oxide (Carbon) nanocomposite.
The negative ion composition of claim 1, wherein the oxide carbon nanocomposite is capable of size dynamic transition.
(a) adding carbon nanostructures to an ethylene glycol solution and dispersing the mixture using ultrasonic waves; (b) adding an Ethylene Glycol solution in which a transition metal precursor is dissolved, and adding 1M aqueous NaOH solution as a reducing agent; (c) reducing the metal salt by heating in a microwave oven for 60 to 120 seconds, and then centrifuging the dispersion at 6000 to 8000 rpm for 10 to 20 minutes; (d) after vacuum drying at 50-70 ° C. after the centrifugation, heat-treating at 250-350 ° C. hydrogen atmosphere, and heat-treating at 200 ° C. in an air atmosphere. Method for producing an ion secondary battery negative electrode composition.
The method of claim 3, wherein the carbon nanostructure is a lithium ion secondary battery negative electrode composition, characterized in that any one selected from the group consisting of nanotubes (CNT), graphene (Graphene) and carbon nanoribbon (carbon nanoribbon) Way.
The method of claim 3, wherein the transition metal is Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, Lu, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Lr, Rf, Db, Sg, Bh, Hs, Mt, Ds, Rg and Cn is any one selected from the group consisting of Method for producing a lithium ion secondary battery negative electrode composition.
The method of claim 3, wherein (e) the oxide-carbon nanocomposite is mixed with polyvinylidene fluoride (PVDF) 9: 1 by weight, and then placed in an N-Methyl-2-pyrrolidone (NMP) solution, and sonication and stirring are repeated. Method for producing a lithium ion secondary battery negative electrode composition, characterized in that it further comprises the step of preparing a carbon nanocomposite paste.

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